![[credit: NASA]](https://tallbloke.wordpress.com/wp-content/uploads/2015/06/air_cloud1.gif)
[credit: NASA]
A few weeks ago we put up a post to discuss the role of convection in the Earth’s atmosphere:
Beginner’s guide to convection cells
The introduction, linked to a short video, said:
‘When you warm air, it rises. Cool air will sink. This process of convection can lead to flows in the atmosphere, in a manner that we can illustrate [see video] on a small scale. Warm and cool air in a fish tank rise and fall; this motion is made visible by adding fog. Ultimately, the motion leads to a convection cell, with air rising, moving to the side, falling, and moving back. This heat-driven motion of air moves heat around in the atmosphere. It is also responsible for making the wind blow.’
That may have seemed straightforward to some, but a few hundred comments later controversy continues, so we’re starting a new post using this website for reference : Lapse Rate, Moisture, Clouds and Thunderstorms
This doesn’t imply endorsement of every statement it makes, but gives us a background to further discussion.
In its introduction it says:
‘One of the key factors to understand in this context is the vertical motion of air parcels, a process referred to as convection.’
That’s probably enough to get the discussion, which is in effect a continuation from the earlier post, started.
[Note: comments on the earlier post (Beginner’s guide – link above) are now closed]
Tallbloke's Talkshop 
Roger C: I think planet gravity causes the gas pressure gradient in an atmosphere.
Good. That means you accept that gravity is one of the causes of the pressure the atmosphere exhibits at differing altitudes.
Let me refer you again to how much difference temperature makes to pressure at surface and altitude:
According to this online calculator At 1km altitude, a change in temperature of 100K from -50C to +50C would alter the air pressure by around 5%. Whereas the effect of gravity on the mass of the atmosphere alters the air pressure by around 13% (at a steady 10C) from surface to 1km.
tallbloke says: February 16, 2016 at 1:03 pm
“Let me refer you again to how much difference temperature makes to pressure at surface and altitude:”
Temperature makes NO difference on the surface pressure at all.
Assuming same gravity and column mass the surface pressure will be exactly the same, whether the surface temperature is -50C or + 50C.
The ‘warm’ column will expand upwards much more than the cold one, so at the same altitude (meters above surface) you’ll find very different numbers for temperature, pressure and density.
H Y D R O S T A T I C E Q U I L I B R I U M.
Ben, you are not correct (but in a manner, you are, if ignoring ‘h’) countering TB, he is speaking of a point at a given altitude, at 1km above the surface, not at the surface, not at a given altitude where the masses above and below are known.
Ben, you did correctly pointed out that if ignoring the forces from all vertical winds, pressure at some vertical altitude depends ONLY on two parameters when dealing with atmospheres, the mass located above that point and the strength of the gravity acceleration, P = F/A = (m/A)*g or more simply P = m/(1 m²)*g when dealing in a unit area of the column for the A is then assumed to be ‘1’ in that case and very so shortly P = m*g though you then KNOW why the units are not correct even though the answer is always correct.
The volume it takes to contain the mass lying above that given altitude in question is completely irrelevant to the pressure found there but that volume does depend on temperature! The warmer the column, the more volume it takes to contain that mass lying above and the opposite if cooler.
But… all said above does not consider ‘h’. The unit column mass lying below that 1km altitude when warmer contains less mass, and the total mass of the atmosphere is conserved, so more mass then lies above that 1 kilometer altitude so pressure will rise. See your slip when ignoring ‘h’? It kind of makes you right but wrong.
“The unit column mass lying below that 1km altitude when warmer contains less mass, and the total mass of the atmosphere is conserved, so more mass then lies above that 1 kilometer altitude so pressure will rise.”
Warm, rising air causes lower pressure at the surface and cold, descending air causes higher pressure at the surface.
How does that fit with the above quote?
Note that I checked the online model at 1km altitude. Someone who has the time could test it at other altitudes too.
I think the answer is that air at the top of the warmer, rising column is displaced sideways to the top of the adjoining colder, descending column such that total mass is NOT conserved between rising and falling columns.
Rising columns contain less mass and falling columns contain more mass but they average out across the globe so that average surface pressure globally is unchanged.
Roger Clague says: February 16, 2016 at 10:40 am
“You accept the cause of this upward force is caused by molecular motion. But a fluid dynamics parcel has no internal properties”.
http://www.merriam-webster.com/dictionary/parcel
[“a volume of a fluid (as air) considered as a single entity within a greater volume of the same fluid”]
In fluid dynamics, or continuum mechanics, such parcel is always the smallest such to have at most two coherent vector momentums (momenta) one linear one angular. Always locatable, no Heisenberg at these scales. In a compressible fluid that ‘volume’ need not be constant, but mass contributing to momenta is fixed. Such is still fully compatible with all gas laws.
RC: “Gas has 10 ^23 molecules in 30cm cube. The motion of the molecules is random and therefore regular and can be predicted by Maxwell-Boltzmann statistical mechanics.”
Agreed ‘lotza!’; but that’s 27 liters, 54 pints!!! At STP, is that not close to 10^24 molecules?
18,000 atmospheric parcels of 10^18 molecules (billion billion) each, still randomly cavorting about in my empty glass, last time I counted 🙂 The atmosphere has no beer glass 😦
All the best! -will
Stephen: “I think the answer is that air at the top of the warmer, rising column is displaced sideways to the top of the adjoining colder, descending column such that total mass is NOT conserved between rising and falling columns.”
Sorry, but in my note to TB and Ben I was not addressing rising warm columns of air when surrounded by cooler air… your packets… remember, convection depends only on density DIFFERENTIALS. If all of the air is warmer evenly, as I was speaking of, there is no automatic rising by convection, no packets. Warmth does no necessarily dictate rising, that only occurs if the surrounding air does not also warm at the same rate so is cooler so more dense.
Stephen: “Rising columns contain less mass and falling columns contain more mass but they average out across the globe so that average surface pressure globally is unchanged.”
Rising columns contain less mass and falling columns contain more mass? Why do you think that?
Please give proof. This is not true if the warmer areas are just taller but contain the same or even greater mass and cooler columns are not as tall, denser. Generally, high pressure areas have MORE mass so higher pressure… did you not read and understand what was written above? I explicitly ruled out movement of the air.
“Rising columns contain less mass and falling columns contain more mass? Why do you think that? ”
How else would you explain lower pressure (less weight/mass) beneath rising columns and higher pressure (more weight/mass) beneath descending columns?
Notwithstanding all of this semi-interesting, continued chatter about convection, it is indisputable that the up-down nature of convection cannot explain the lateral and highly focused flow of the jet streams. Thus there must be some other source of flow in the atmosphere that is independent of convection. Given the jet streams magnitude–supporting wind speeds upward of 300 mph–it is undeniable that this unnamed alternate source of flow is much more energetic than is that of convection. Moreover, there is no reason not to speculate that this unnamed form of flow might on occasion be oriented vertically to explain some, or even most all, of the observations that have been attributed to convection.
tallbloke says: February 16, 2016 at 1:03 pm
(Roger C: “I think planet gravity causes the gas pressure gradient in an atmosphere.”)
“Good. That means you accept that gravity is one of the causes of the pressure the atmosphere exhibits at differing altitudes. Let me refer you again to how much difference temperature makes to pressure at surface and altitude:”
Good some progress. To clarify about temperature! Consider a hollow sphere of radius 6000km with Earth’s atmosphere contained is an elastic balloon providing a compressive force at an additional radius of 100km the same as current 100km pressure. With no gravitational force whole thing may be at just the low but isothermal temperature sufficient to cause that now isobaric pressure of Earth’s 100km altitude. Now we start up the gravity machine by adding the mass of all climatastrophists to the interior of the sphere! By by!!
This part may clarify or confuse the following. Please delete/ignore if confusing; It is not necessary! Add some sensible heat to the isobaric gas. Temperature increases yet molarity/mass remained constant but whether density decreases or pressure increases depends on the elastic function of the balloon! If near elastic limit (rigidity) volume remains constant and the Cv specific heat is used. If still limp pressure remains constant and Cp specific heat is used!
As climatastrophist mass (planetary-kg) is added to the sphere gravity develops an attractive force in Newtons ∝ (local-kg x planetary-kg)/(distance²)! Earth norm is 9.8 N/(local-kg) at (6400km)²!! Local airmass 34.5 atmospheric moles/kg.
As this force develops the moles are compressed toward the surface via ‘work’ done on the moles compressed, and sensible heat increases as indicated by rising surface temperature, pressure,density. However as the compression work is done, there are fewer of the moles to compress left at higher altitude, less work less temperature, pressure, density, increase result and the observed gradients are established. Balloon stress is replaced gravitational force and balloon removed.
This is precisely the way gravity may add to atmospheric mass if such gas is accumulated from space. If accumulated from the surface or planet such gas must already be at the correct temperature, pressure, density.
The only other effect gravity has on the atmosphere is to accelerate downward mass motion and decelerate upward mass motion. This greatly assists the creation and operation of the Hadley, Ferrel, and Polar circulation cells but does nothing at all in the meteorological fantasy of convection. Lateral mass motion at constant pressure is not affected. Notice the different structure of the free atmosphere from that of an isobaric container. Both have increasing density downward. However: Free atmosphere in gravitational field has increasing pressure and temperature downward, while isobaric structure in gravitational field has increasing temperature upward!
This lets the climatastrophist believe that increasing power to airmass creates buoyancy from his fantasy hydrostatic equilibrium! All the additional power does is expand the gas at constant pressure, under the careful supervision of gravity!! What is left to do is to determine the actual atmospheric mass avoiding the error of Blaise Pascal,
A compressive fluid does not stack like bricks!!
All the best! -will-
Stephen Wilde says: February 16, 2016 at 9:18 pm
“Rising columns contain less mass and falling columns contain more mass? Why do you think that? ”
“How else would you explain lower pressure (less weight/mass) beneath rising columns and higher pressure (more weight/mass) beneath descending columns?”
The opposite is true! All clearly explained via fluid dynamics and the required continuum mechanics! The opposition of surface pressure to vertical motion is because the continuum diverts mass flow from/to such regions creating static highs and lows instead!
Roger Clague says: February 15, 2016 at 6:45 am
“I see your point. The Earth’s field is a mono-directional isotropic field. It is in one direction at each point on its isotropic surface, UK or NZ.”
Well yes, but it doesn’t have a “surface”. Its a ‘~spherical field’ that encompasses a central focus.
The term ‘Barry center (special case)’ may well cause confusion in the discipline of Astronomy, thus, as an Engineer, I’ll use the term ‘focus of the gravity field’ in future if this helps. It may also aid a better understanding of ‘anomalies’ within the ‘gravity field strength’ category.
“The gas molecular force fields and the gas pressure are different.”
??? That should be obvious RC. No atom on the Atomic Scale is equal, and no molecule in the spectra of compounds is equal. The ‘obvious’ difference is in the ‘mass’ property, but a more ‘hidden’ difference is in the ‘isotope’ inclusion (I’ll not go into ‘isotope inclusion’ here).
To keep it simple, the mass properties of variant molecules differs and the electrostatic properties of variant molecules differs. Thus, there are ‘two’ ‘fields/degrees of freedom’ extant here.
For the ‘electrostatic property’ every individual molecule possesses its own ‘electrostatic field’. This ‘field’ ensures that no other molecule make a ‘contact/collision interaction’ with other molecules. A ‘contact/collision interaction’ would flag a ‘recombination event’ and generate an inquiry about a ‘chemistry event’. This requires either a high energy ‘outside’ force and is my best approximation to ‘hydrostatic equilibrium’ where the “‘outside’ force” is quiescent and no chemical activity exists, but this doesn’t have much to do with convection.
This is ~seen as ‘microscopic pressure’.
OTOH (the ‘gravity’ POV), the ‘gravity field’ generates a ‘force’ that pushes ‘everything’ (mass entities) towards the ‘focus of the gravity field’. This is where the ‘fields/degrees of freedom’ become blurred.
Molecular repulsion from static potential explains the gaseous state of an atmosphere and pressure, but the ‘inertia value’ also explains the relevant mass involved within the observation. Molecules at the the same ‘state of excitation’ that posses a ‘greater mass’ share the same ‘kinetic energy’ with molecules that posses a ‘lesser mass’. Logic suggests that molecules with a ‘greater mass’ travel ‘slower’ than molecules with a ‘lesser mass’ to conserve the local energy constant.
_______________________________________________________
RC, I’ve already been too slow to respond properly to your post (this thread has ‘lurched’ forwards), but I’ll leave you with this thought for your closing POV.
“My point of reference is a gas molecule.”
Which one??? Why??? This may well give you insight into the way that gasses ‘stratify’ or ‘mix’, but the ‘gravity field’ is missing.
‘Containment by gravity’ is worlds away from the ‘fixed barrier containment’ employed by chemists.
IMHO you need to make your “reference frame” the “center of focus” for “Earth’s gravity field”. 🙂
Don’t be a stranger, ask what you want to know. If I don’t know, there’s always another poster’s POV. 🙂
Best regards, Ray.
Stephen Wilde says: February 16, 2016 at 9:18 pm
“How else would you explain lower pressure (less weight/mass) beneath rising columns and higher pressure (more weight/mass) beneath descending columns?”
It’s complicated, but if we ever get into the realm of ‘inertia’ the/your questions may be answered. ‘Coriolis effect’ is the ‘culprit’ 😉 .
Best regards, Ray.
Stephen Wilde says:
How else would you explain lower pressure (less weight/mass) beneath rising columns and higher pressure (more weight/mass) beneath descending columns?
Jet streams
wayne says: February 16, 2016 at 5:38 pm
“Ben, you are not correct (but in a manner, you are, if ignoring ‘h’) countering TB, he is speaking of a point at a given altitude, at 1km above the surface, not at the surface, not at a given altitude where the masses above and below are known.”
tallbloke says: February 16, 2016 at 1:03 pm
“Let me refer you again to how much difference temperature makes to pressure AT SURFACE and altitude:”
Notice ‘AT SURFACE’.
“Ben, you did correctly pointed out that if ignoring the forces from all vertical winds, pressure at some vertical altitude depends ONLY on two parameters when dealing with atmospheres, the mass located above that point and the strength of the gravity acceleration”
I would expect this to be ready knowledge for everybody discussing atmospheres.
I’m not aware of any way to calculate the pressure / temperature at a certain height above the surface given a surface pressure and temperature
You can make a general statement like I did, that in a much warmer column the varies pressure levels will be higher above the surface than in a colder column.
For details you need to MEASURE temperature, relative humidity etc.etc.
James McGinn says: February 16, 2016 at 10:43 pm
“Thus there must be some other source of flow in the atmosphere that is independent of convection. Given the jet streams magnitude–supporting wind speeds upward of 300 mph–it is undeniable that this unnamed alternate source of flow is much more energetic than is that of convection. ”
This unnamed source is called ‘thermal wind’.
Well understood mechanism, and closely related to hydrostatic equilibrium.
Thermal wind is the DRIVING force behind Global Circulation Cells, jetstreams etc.
Ben Wouters says: February 17, 2016 at 10:10 am
This unnamed source is called ‘thermal wind’.
Well understood mechanism, and closely related to hydrostatic equilibrium.
Thermal wind is the DRIVING force behind Global Circulation Cells, jetstreams etc.
How is it that your highly entropized “thermal;wind” somehow reverses entropy to produce, tight, high velocity stream flows? You label it as, “well understood.” Yet you offer no explanation whatsoever. It seems to me you are pretending to explain what you have not.
Stephen Wilde says: February 16, 2016 at 6:31 pm
“…”
Is this a ‘light bulb’ moment. Do you finally realise that ‘inertial momentum’ alters ‘surface pressure’? I’m unsure.
‘Inertial momentum’ is generated by both ‘convection’ and ‘advection’. Any distinction between the two atractors requires a ‘back-track tracing’ provenance to ‘the source’ of the ‘energy input’ (KE) for a ‘full’ analysis.
Your recognised ‘energy input’ for ‘KE’ is ‘global’, ‘regional’ and ‘local’. How would you rationalise the distinction of these ‘levels’ of observation to distinguish between them?
Best regards, Ray.
Ben Wouters says, February 17, 2016 at 10:10 am:
“Thermal wind is the DRIVING force behind Global Circulation Cells, jetstreams etc.”
Ben, again, uneven surface warming and deep moist convection constitute the DRIVING force behind the Hadley Cells. This is common knowledge.
Kristian says: February 18, 2016 at 6:26 am
Ben, again, uneven surface warming and deep moist convection constitute the DRIVING force behind the Hadley Cells. This is common knowledge.
Kristian, I think it plainly obvious that moist air is heavier than dry air. I say this not only because it is physically impossible to produce gaseous H2O at ambient temperatures and only if H2O was gaseous could it possibly be lighter [Snip]
[Reply] We’ve already been round this straw man. Evaporation occurs because individual H2O molecules can be knocked free from liquid water by high energy incident photons (sunlight). You then claimed that 100 singleton H2O molecules dispersed in 10,000 N2 and O2 molecules had a very strong attraction to each other. Still waiting for some evidence relating to that.
Ben Wouters says:
February 16, 2016 at 3:06 pm
tallbloke says: February 16, 2016 at 1:03 pm
“Let me refer you again to how much difference temperature makes to pressure at surface and altitude:”
BW: Temperature makes NO difference on the surface pressure at all.
Assuming same gravity and column mass the surface pressure will be exactly the same, whether the surface temperature is -50C or + 5
BW is correct. According to HE (which I don’t agree with) pressure is caused by weight. Weight does not change with T. The temperature of water a fluid) does not change pressure of water. Also Derivation of HE (e.g. Feynmann) assumes T constant.
T/h is linear; p/h is a step upward curve. T does not cause p and p does not cause T in the atmosphere.
suricat says:
February 17, 2016 at 2:21 am
Molecular repulsion from static potential explains the gaseous state of an atmosphere and pressure, but the ‘inertia value’ also explains the relevant mass involved within the observation. Molecules at the the same ‘state of excitation’ that posses a ‘greater mass’ share the same ‘kinetic energy’ with molecules that posses a ‘lesser mass’t.
I agree air pressured caused by Inertia and repulsion from static potential (charge?)
Pressure, inertia and charge repulsion are each equal in all directions.isotropic.
It is surprising that pressure does not depend on mass of gas molecules
P = momentum= Mass(m) x number of collisions(n) x velocity of each collision(v).
Increasing m of a molecule decreases v and n by m^-1/2
So m cancels
Leaving p = n x v
Logic suggests that molecules with a ‘greater mass’ travel ‘slower’ than molecules with a ‘lesser mass’ to conserve the local energy constant
According to Kinetic theory of gas v is proportional to m^-1/2
Kristian says:
February 18, 2016 at 6:26 am
Ben Wouters says, February 17, 2016 at 10:10 am:
“Thermal wind is the DRIVING force behind Global Circulation Cells, jetstreams etc.”
K: Ben, again, uneven surface warming and deep moist convection constitute the DRIVING force behind the Hadley Cells.
RC: Convection is vertical, wind and Jetstreams are horizontal, Hadley cells are vertical and horizontal.
Wind is caused by pressure difference not temperature difference
Vertical and horizontal movements of air have different properties and causes and needs a different theory.
Vertical, molecular Kinetic theory, horizontal non-molecular continuum mechanics
Roger Clague says, February 18, 2016 at 2:55 pm:
Well, sure. But then again, I’m not saying thermal wind isn’t an integral part of the circulation. It is indeed. However, the bone of contention here is what sets the movement in motion to begin with; what is the ultimate originator of what ends up a large-scale tropospheric circulation cell?
And there’s no question that the answer to this is uneven surface heating and deep moist convection.
What happens is simply that the Sun heats the surface and it does so most intensely at the equator. A mean zonal gradient naturally develops both in temperature and evaporation rates from higher to lower latitudes. Air starts rising from the solar-heated surface wherever and whenever the Sun beats down, but the closer you get to the equator, the more powerful this effect becomes on average, and so this is where the upward motion will ultimately centre, because the air masses further away from the equator will preferentially be drawn in horizontally to this region of fastest-rising air. At this point, though, the thermal wind has already started working, because as soon as the air lifts more and heats more at the equator than away from it, the air column will also stretch more in the vertical direction at the equator than away from it, and so there will be an altitudinal pressure gradient from the equator out to the sides.
However, the thermal wind would never develop unless the surface weren’t unevenly heated in the first place, so that the tropospheric column above could also be unevenly heated, generating the necessary altitudinal pressure gradient in the process.
But yes, both vertical and horizontal mechanisms are of course important, even necessary, to maintain the overall circulation.
Wikipedia says the thermal wind is really a wind shear – but admits its ‘article has multiple issues’ and ‘needs attention from an expert in Meteorology.’ (September 2012)
http://en.wikipedia.org/wiki/Thermal_wind
“Kristian says: February 18, 2016 at 5:43 pm”
“”Roger Clague says, February 18, 2016 at 2:55 pm:””
“”RC: Convection is vertical, wind and Jetstreams are horizontal, Hadley cells are vertical and horizontal.
Wind is caused by pressure difference not temperature difference””
“Well, sure. But then again, I’m not saying thermal wind isn’t an integral part of the circulation. It is indeed. However, the bone of contention here is what sets the movement in motion to begin with; what is the ultimate originator of what ends up a large-scale tropospheric circulation cell?
And there’s no question that the answer to this is uneven surface heating and deep moist convection.”
I disagree Kristian. ‘Deep moist convection’ is truly a part of this phenomenon by way of a natural ‘diffusion pump’;
https://en.wikipedia.org/wiki/Diffusion_pump
which caries molecules of gas with this forced direction of a controlled and unmixable medium.
When I was introduced to this type of ‘pump’ the analogy made was “imagine that you’re trying to get into a football stadium when the match is over and every one else is trying to get out”. This ‘is’ the case for ‘WV’ (Water Vapour)!
WV is ~three fifths the density of the average density of other atmospheric components, thus ‘rises’ through the ‘other’ atmospheric components presenting as a ‘medium’ that can convey ‘other’ molecules (by WV diffusion) ‘vertically’ by way of its ‘convection’ property!
However, if you want to imply that solar heating causes “a large-scale tropospheric circulation cell” you are correct, but ‘temperature’ isn’t the means of the forcing. Its the energy absorbed by ‘phase change of H2O’! Temperature change from insolation is always ‘nullified’ by the ‘nocturnal phase environment’ of a nocturnal/diurnal day. The atmosphere ‘cools’ again at night to ‘~the same temperature’ it started at on the previous day. The low ‘specific gravity’ of WV in the atmosphere generates a ‘dissimilar density convection’ (please note that all low pressure regions are ‘wet’, and that all high pressure regions are dry on a ‘weather chart’), and that’s besides the fact that WV gas is continually produced at Earth’s surface.
“But yes, both vertical and horizontal mechanisms are of course important, even necessary, to maintain the overall circulation.”
The ‘counterpoise’ to Earth’s gravity field, generated by Earth’s rotational moment, is a phenomenon that includes “both vertical and horizontal mechanisms” in ‘one phenomenon’, commonly understood to be the ‘Coriolis effect’. This ‘effect’ is ‘vertical’ at the equator and ‘horizontal’ at each pole. In ‘engineer speak’, we have a ‘planar turbine’ at each pole with a ‘radial turbine’ at the equator. Small wonder that we get the Polar and Hadley cells, with the Ferrel cells ‘idling’ between them.
‘The Jets’ are composed of ‘high velocity’ gasses that are unable to mix with the dynamic of the Ferrel cell in each hemisphere. IOW, the ‘blow off valve’ for the ‘turbines’. 😉
Where’s the ‘thermal’ here?
Clear as mud, eh. 🙂
Best regards, Ray.
suricat says:
February 20, 2016 at 1:21 am
WV is ~three fifths the density of the average density of other atmospheric components, thus ‘rises’ through the ‘other’ atmospheric components presenting as a ‘medium’ that can convey ‘other’ molecules (by WV diffusion) ‘vertically’ by way of its ‘convection’ property!
I agree. The Hadley Convection cell is caused by WV buoyancy.
The Hadley Convection cell is the water cycle. That is, similar to storm formation on a larger scale.
The water cycle is not caused by temperature difference.It is a diffusion pump pushed by the buoyancy of water vapor (WV) and pulled by the reduced pressure caused by WV condensing.
Atmospheric convection is not like convection in a liquid. In a liquid a convection cell is caused by vertical temperature difference and called Rayleigh-Bernard convection.
oldbrew says: February 18, 2016 at 9:36 pm
“…”
IMHO that subject can’t be rationalised by ‘temperature’ and ‘heat’ (thermal) in isolation. More understanding is demanded from disciplines that encompass ‘moments and inertia’ studies with rudimentary introductions to ‘Earth’s centrifuge’ and a more advanced study of the ‘behavior of Earth’s atmospheric hydrological cycle’. There are ‘many’ atractors at work here, but ‘thermal’?
Perhaps if the thermal ‘source’ is immediately ‘sunk’ (‘sink’-ed) into another atractor we would hardly be able to observe it.
Best regards, Ray.
suricat says: February 21, 2016 at 1:02 am
oldbrew says: February 18, 2016 at 9:36 pm
(“…””
“IMHO that subject can’t be rationalised by ‘temperature’ and ‘heat’ (thermal) in isolation.”
This is where Roger Clague’s interpretation becomes important!! Without mass per se, only moles of atmosphere, the instantaneous can be interpreted as local power in (solar flux); work in progress, accelerations, expansions, state of matter, interesting weather; and local waste power out (generally EMR exitance to space), and can be considered as determining local temperature, pressure, density. The resultant dQ/dt = (is) power that needs not be conserved, but accounted!
“More understanding is demanded from disciplines that encompass ‘moments and inertia’ studies with rudimentary introductions to ‘Earth’s centrifuge’ and a more advanced study of the ‘behavior of Earth’s atmospheric hydrological cycle’. There are ‘many’ atractors at work here, but ‘thermal’?
Indeed! Once you have a language (communication) for instantaneous state, power, and work in progress; we can start to develop a discussion, of the atmospheric dynamic Convection, the relocation of atmospheric moles about the atmosphere via ‘work’. In this atmosphere the instantaneous of, admittedly remains a fantasy, just begging for better fantasy of. Believers need not apply!!
Such ‘work involves the temporary accumulation of power ‘as energy’ in such concepts as sensible heat, latent heat, linear and angular momentum; and of course single malt scotch! The massless atmosphere in moles (only Avogadro’s number of thingys, perhaps countable, but with no inertia) easily converts to inertial mass when needed, as each atmospheric mol exhibits 29-30 grams of mass depending number of local insects in flight! Unfortunately the location of ‘each’ your brand of atmospheric thingys or the COM all such, must remain unknown.
The mass of anything is of consideration only for relative motion to some inertial reference. If you wish this to be easy; go pray to the SKS site!!
“Perhaps if the thermal ‘source’ is immediately ‘sunk’ (‘sink’-ed) into another atractor we would hardly be able to observe it. Best regards, Ray.”
Is that the wimp version of “beats the shit outta me!”?
All the best! -will-
suricat says:
February 20, 2016 at 1:21 am
WV is ~three fifths the density of the average density of other atmospheric components, thus ‘rises’ through the ‘other’ atmospheric components presenting as a ‘medium’ that can convey ‘other’ molecules (by WV diffusion) ‘vertically’ by way of its ‘convection’ property!
I agree.
The Hadley Convection Cell is (HCC) the water cycle caused by the buoyancy of water vapor (WV).
The evaporation and condensation of WV causes vertical movement by diffusion.
The HCC is not caused by temperature difference at top and bottom as in the Rayleigh-Bernard Convection Cell (RBCC). The RBCC occurs in liquid water not the gas atmosphere.
No all convection cells have the same cause.
Sorry for the delay Roger C, it’s been a busy weekend on the politics front.
James McGinn says: February 17, 2016 at 7:53 pm
“How is it that your highly entropized “thermal;wind” somehow reverses entropy to produce, tight, high velocity stream flows? You label it as, “well understood.” Yet you offer no explanation whatsoever. It seems to me you are pretending to explain what you have not.”
see http://www.recreationalflying.com/tutorials/meteorology/section1b.html#thermal_wind
for an explanation at beginners level.
Kristian says: February 18, 2016 at 6:26 am
“Ben, again, uneven surface warming and deep moist convection constitute the DRIVING force behind the Hadley Cells. This is common knowledge.”
Uneven surface heating yes, obviously, since it is responsible for the uneven expansion of atmospheric columns creating increasing horizontal pressure differences with increasing altitude.
Deep moist convection obviously not, since convection is a very localized phenomenon (few 10s of kilometers, not thousands like in the Hadley circulation..
James McGinn says: February 18, 2016 at 7:06 am
“Kristian, I think it plainly obvious that moist air is heavier than dry air. I say this not only because it is physically impossible to produce gaseous H2O at ambient temperatures and only if H2O was gaseous could it possibly be lighter”
see http://www.recreationalflying.com/tutorials/meteorology/section1a.html#atmospheric_moisture
for another explanation at the beginners level.
Kristian says: February 18, 2016 at 5:43 pm
Finally beginning to understand Hydrostatic Equilibrium?
Roger Clague says: February 18, 2016 at 2:55 pm
Apologies for missing/overlooking your embedded response RC.
“I agree air pressured caused by Inertia and repulsion from static potential (charge?)”
Yes, ‘charge’. The ‘static electrical potential’ of a molecule determines the ‘compressibility factor’ for the entity IMHO.
“Pressure, inertia and charge repulsion are each equal in all directions.isotropic.”
I concur.
“It is surprising that pressure does not depend on mass of gas molecules”
That’s because each molecule possesses its own electrostatic ‘signature’ within the ‘gas mix’. ‘Pressure’ is an ‘accepted approximation’ of the ‘mix’ that doesn’t reflect on the potential of the individual components of the ‘mix’.
“P = momentum= Mass(m) x number of collisions(n) x velocity of each collision(v).
Increasing m of a molecule decreases v and n by m^-1/2
So m cancels
Leaving p = n x v”
Honestly, this is ‘nonsensical’ to me RC. 😦
All I understand is that for any ‘massive object’ ‘1/2 mass x velocity^2 = the inertia value encompassed/encountered within a given “reference frame”‘. Your ‘formulae’ may well transpose correctly, but without the ‘inertial reference frame’, I can’t follow it.
Your statement of “m^-1/2” (mass to the power of -0.5) also has me ‘miffed’.
“According to Kinetic theory of gas v is proportional to m^-1/2”
There’s something ‘odd’ here. ‘Velocity’ is the ‘speed in a given direction’ that an object moves WRT the ‘observer’. ‘Where’ is the ‘observer’ in this demonstration? Knowing this would give us our ‘reference frame’ that can distinguish ‘potential from kinetic’ energy in the ever changing focus of our modern world of science.
Again, apologies for missing this embedded post.
Best regards, Ray.
suricat says: February 22, 2016 at 2:36 am.
“Yes, ‘charge’. The ‘static electrical potential’ of a molecule determines the ‘compressibility factor’ for the entity IMHO.”
Kinda sorta! kT/t is the electrical statistical ‘noise power’ associated with electric charge potential of any known substance. A linear function of temperature according to Luddy Boltzmann, and now measurable over now 4.5 orders of magnitude. Likely more linear than any other known measurement of temperature. The ktb(w) noise of a resistor is exactly this as limited by the frequency response of some environment variable say capacitance. But capacitance exhibits the same noise variance known as kTC (charge variance) or kT/C (voltage variance) noise that is independent of voltage potential or actual difference in charge across the dielectric. This noise exists even as the potential and charge go through zero and reverse in polarity. Mostly undetectable except at temperatures below 40 Kelvin. No one can yet demonstrate if this is dimensional variance in the dielectric or just wiggles in the surrounding electric field ‘cloud’ very very active at higher temperatures.
The repulsive nature of like charge is demonstrated by ‘pith’ balls or the ancient electroscope. At STP atmospheric intermolecular distances average 30 Angstroms and exhibit repulsive force eight orders of magnitude greater than the gravitational attractive force between the same molecules. It is this noise power as measured by temperature that provides all measurable gas pressure.
At some Pressure-Temperature-Density this intermolecular repulsive force equals the compressive force of Earth’s gravity on each molecule. No further spontaneous atmospheric expansion into outer regions of lesser repulsive force will occur . Here is where your inertia comes into play. Any molecule with velocity relative to any equilibrium point between such repulsive/compressive forces can use its own vector momentum to sail on through. No need for, STOP, papers please, or even stopping to take a pith!
“All I understand is that for any ‘massive object’ ‘1/2 mass x velocity^2 = the inertia value encompassed/encountered within a given “reference frame”‘. Your ‘formulae’ may well transpose correctly, but without the ‘inertial reference frame’, I can’t follow it.”
Ray,
That is Kepler’s KE that must be conserved with gravitational force x distance PE, according to some clueless folk.
Inertia OTOH, “resistance to change in momentum”, requires no velocity relative to anything. Inertia may well be the only definition of mass! Folk like to poke at mass; inertia always pokes back! . This poking at is called ‘applying force’!
‘There’s something ‘odd’ here. ‘Velocity’ is the ‘speed in a given direction’ that an object moves WRT the ‘observer’. ‘Where’ is the ‘observer’ in this demonstration? Knowing this would give us our ‘reference frame’ that can distinguish ‘potential from kinetic’ energy in the ever changing focus of our modern world of science. Again, apologies for missing this embedded post. Best regards, Ray.”
To gather any understanding of this atmosphere multiple reference frames or POV’s are required. Your focus of Earth’s gravity is new to me but quite valid. Roger Clague’s each molecule POV clearly explains buoyancy, “Dese guys are crowding me, I’m getten the hell outa here if I can!”.
I use “from each pole”, to explain young Eötvös dancing with fetching Coriolis. I use a POV from L1, L2 to explain effects of insolation, a stationary directional source of power that expands the local absorbing atmosphere. A POV from the Moon returns me to my comfortable “beats the shit outta me!”.
The POV of flat Earth astrologers on their moving, rotating, reference frame, and calling their fantasy Meteorology or Climatology science I refuse to accept. All is Neptune going into the house of Leo!
All the best! -will-
Will Janoschka says: February 22, 2016 at 7:21 am
“Kinda sorta! kT/t is the electrical statistical ‘noise power’ associated with electric charge potential of any known substance. A linear function of temperature according to Luddy Boltzmann, and now measurable over now 4.5 orders of magnitude. Likely more linear than any other known measurement of temperature. The ktb(w) noise of a resistor is exactly this as limited by the frequency response of some environment variable say capacitance. But capacitance exhibits the same noise variance known as kTC (charge variance) or kT/C (voltage variance) noise that is independent of voltage potential or actual difference in charge across the dielectric. This noise exists even as the potential and charge go through zero and reverse in polarity. Mostly undetectable except at temperatures below 40 Kelvin. No one can yet demonstrate if this is dimensional variance in the dielectric or just wiggles in the surrounding electric field ‘cloud’ very very active at higher temperatures.”
What you describe sounds like either ‘white or ‘pink’ ‘noise’ introduced into an electrical circuit by either or both the ‘environment’ and the ‘substance’ of the circuit. Perhaps a distinction between ‘white’ and ‘pink’ can differentiate the action for the ‘circuit’ or/and its ‘environs’. 🙂
“The repulsive nature of like charge is demonstrated by ‘pith’ balls or the ancient electroscope. At STP atmospheric intermolecular distances average 30 Angstroms and exhibit repulsive force eight orders of magnitude greater than the gravitational attractive force between the same molecules. It is this noise power as measured by temperature that provides all measurable gas pressure.”
I concur. STP is the standard used, but ‘STP’, per se, hardly exists in Earth’s atmosphere. However, ‘static charge’ trumps ‘gravity’ at Earth’s surface and ‘uncharted regions’ display other ‘standards’. IMHO we need another ‘standard’, and IMHO this should be ‘electrostatic stress’.
‘Electrostatic stress’ directly represents ‘pressure’, but also indicates the atractor that causes the phenomenon. Thus, “hydrostatic equilibrium” becomes the “electrostatic equilibrium” that can differentiate between the ‘liquid’ and ‘gas’ phases of mass in a ‘fluid state’.
“At some Pressure-Temperature-Density this intermolecular repulsive force equals the compressive force of Earth’s gravity on each molecule. No further spontaneous atmospheric expansion into outer regions of lesser repulsive force will occur . Here is where your inertia comes into play. Any molecule with velocity relative to any equilibrium point between such repulsive/compressive forces can use its own vector momentum to sail on through. No need for, STOP, papers please, or even stopping to take a pith!”
This is the ‘fluid state’ that Ben Wouters refers to as “Hydro-static Equilibrium”! Yes, ‘every point in the atmosphere’ is ‘floating’ with ‘~no change’ to inertial values other than the ‘viscosity’ of the mass under observation.
suricat said:“All I understand is that for any ‘massive object’ ‘1/2 mass x velocity^2 = the inertia value encompassed/encountered within a given “reference frame”‘. Your ‘formulae’ may well transpose correctly, but without the ‘inertial reference frame’, I can’t follow it.”
“Ray,
That is Kepler’s KE that must be conserved with gravitational force x distance PE, according to some clueless folk.
Inertia OTOH, “resistance to change in momentum”, requires no velocity relative to anything. Inertia may well be the only definition of mass! Folk like to poke at mass; inertia always pokes back! . This poking at is called ‘applying force’!”
I realise that Will. Look to ‘inefficiency’ to discover the ‘sinks’ of energy! These ‘sinks’ show where the ‘energy’ went/goes.
suricat said:”There’s something ‘odd’ here. ‘Velocity’ is the ‘speed in a given direction’ that an object moves WRT the ‘observer’. ‘Where’ is the ‘observer’ in this demonstration? Knowing this would give us our ‘reference frame’ that can distinguish ‘potential from kinetic’ energy in the ever changing focus of our modern world of science. Again, apologies for missing this embedded post. Best regards, Ray.”
“To gather any understanding of this atmosphere multiple reference frames or POV’s are required. Your focus of Earth’s gravity is new to me but quite valid. Roger Clague’s each molecule POV clearly explains buoyancy, “Dese guys are crowding me, I’m getten the hell outa here if I can!”.
I use “from each pole”, to explain young Eötvös dancing with fetching Coriolis. I use a POV from L1, L2 to explain effects of insolation, a stationary directional source of power that expands the local absorbing atmosphere. A POV from the Moon returns me to my comfortable “beats the shit outta me!”.
The POV of flat Earth astrologers on their moving, rotating, reference frame, and calling their fantasy Meteorology or Climatology science I refuse to accept. All is Neptune going into the house of Leo!
All the best! -will-”
No Will. A singular POV is required to make any sense of Earth’s atmosphere.
IMHO this should be Earth’s ‘centric gravity point’ (Barycentre) and a better way to describe/explain ‘hydrostatic equilibrium’.
Best regards, Ray.
suricat says:
February 25, 2016 at 3:32 am
A singular POV is required to make any sense of Earth’s atmosphere.
IMHO this should be Earth’s ‘centric gravity point’ (Barycentre) and a better way to describe/explain ‘hydrostatic equilibrium’.
When I say the point of view (POV) of each molecule is critical, I mean:
1. The motion of each molecule in a gas is random, independent, statistical, inertial and isotropic.
2. Intermolecular gravity and charge forces are 10^8 x Earth’s gravity force.
3. Earth’s gravity field causes the vertical pressure gradient.
You appear to be inconsistent.
You say previously that inertial mass (independent of Earth’s gravity) is important.
Above you say Earth’s gravity field is the correct POV.
Roger Clague says: February 25, 2016 at 10:37 am
“When I say the point of view (POV) of each molecule is critical, I mean:”
“1. The motion of each molecule in a gas is random, independent, statistical, inertial and isotropic.”
I concur, but you’ve left out ‘penetration’ by ‘diffusion’ (yet another statistical assumption). Each molecule that alters its position within a gas mix does so by ‘diffusion’.
The energy requirement for this process can only be supplied by the local environment, thus, the ‘distance’ a molecule can be ‘diffused’ is limited by the energy available within the vicinity of the molecule to be ‘diffused’.
Hence, the ‘radius’ of ‘diffusion’ is limited by the local energy surplus and the local population/volume of the locality under observation (even with a ‘double kick’ to a local ‘heavy’ pollutant molecule).
“2. Intermolecular gravity and charge forces are 10^8 x Earth’s gravity force.”
I suspect that this is a ‘near surface’ observation, so concur. Its at the ‘bottom of the heap’!
“3. Earth’s gravity field causes the vertical pressure gradient.”
Only ‘indirectly’. The “vertical pressure gradient” is generated by the ‘mass’ in ‘Earth’s atmosphere’ within Earth’s gravity field.
“You appear to be inconsistent.
You say previously that inertial mass (independent of Earth’s gravity) is important.
Above you say Earth’s gravity field is the correct POV.”
This ‘is’ consistent RC. The ‘value/weight’ of a mass/massive ‘object’ is disclosed by the continued application of a ‘given’ force to the object. This (given) ‘force application’ discloses the ‘weight/mass’ of the ‘object under investigation’ by way of the rate of acceleration of the object. This also ‘transposes’ as local ‘gravity constraints’ on the subject under consideration (which is compromised by ‘pressure’ [electrostatic equilibrium]). Earth’s gravity obfuscates a ‘clean’ observation IMHO by generating ‘an atmosphere’ in the first place.
Best regards, Ray.
Suricat says: February 25, 2016 at 3:32 am
…
Thank you Ray, Always nice to be straitened out about what I think I know! More belief #2 🙂
Roger Clague says: February 25, 2016 at 10:37 am
……
Thank you Roger, Nice to hear from one with sufficient experience to declare “steady on the rudder, forget the heel of the keel, I can get us through this mess, again!!!” 🙂 Much more belief #2!
suricat says: February 26, 2016 at 1:23 am
Roger Clague says: February 25, 2016 at 10:37 am
(“When I say the point of view (POV) of each molecule is critical, I mean: 1. The motion of each molecule in a gas is random, independent, statistical, inertial and isotropic.”)
“I concur, but you’ve left out ‘penetration’ by ‘diffusion’ (yet another statistical assumption). Each molecule that alters its position within a gas mix does so by ‘diffusion’.”
Ray, Why such pedantic-acy? Is that a word?, you get the idea. We have recorded measurements of:
1. Same sea level atmospheric pressure, 101.3kPa ±34Pa, independent of temperature at almost all surface locations day and night! Why?
2. Almost linear decrease in atmospheric temperature with increasing altitude at any location independent of local surface temperature! Why?
3. While surface pressure remains constant and lapse rate remains constant, the altitude of 15 kPa atmospheric pressure varies 2:1 from equator to poles, and 1:3 from before dawn to mid afternoon at summertime latitudes. Why?
You claim a single POV is sufficient. Why? I treat each POV as a non-orthogonal partial differential equation. I can handle 5 with beer! By 6 partials, I must go to Glenfiddich. Gets kinda spendy!!
My point I wish to express again, is that no one or group has the slightest clue as to how this atmosphere may work. Any claim of such must be an attempt at deliberate scam!
All the best! -will-
Will, you have no clue! I agree.
————————————————————————————–
“1. Same sea level atmospheric pressure, 101.3kPa ±34Pa, independent of temperature at almost all surface locations day and night! Why?”
Due to the fact that pressure does not depend on temperature, at all. P = m·g and that has been proven true long ago.
————————————————————————————–
“2. Almost linear decrease in atmospheric temperature with increasing altitude at any location independent of local surface temperature! Why?”
This is due to the fact that, for some reason, and I personally have had a problem answering the exactly why, that the exponent used in the thermo equations which allows you to calculate the pressure, density and temperature at any location within a troposphere up to the tropopause in any thick enough atmosphere have a difference of exactly one. Why exactly exactly “one” is the harder question that explains why the “Almost linear decrease in atmospheric temperature with increasing altitude”.
The suffix ‘0’ is at the reference point vertically, usually taken to be at the surface.
P = P0 * (T / T0) ^ (exponent)
D = D0 * (T / T0) ^ (exponent minus 1)
This value for the “exponent” which varies from different atmospheres to other atmospheres comes from the fact that:
exponent = log(P/P0) / log(T/T0) = a constant for a given atmosphere.
These hold true for the temperature, pressure and density data for the probes (or radiosondes) dropped into various atmospheres, venus, saturn, titan, etc, and of course earths’.
Why physically is it “minus one”?? A better question to answer.
An example using oldbrew’s standard atmosphere for the initial values:
————————————————
setprec(6)
————————————————
// Two data points within some troposphere
// at 0 km above surface
T0 = 288.15‹K›
P0 = 101325‹Pa›
D0 = 1.225‹kg/m³›
————————————————
// at 11 km
T11 = 216.65‹K›
P11 = 22632.1‹Pa›
D11 = 0.363918‹kg/m³›
————————————————
TG = 0.0065‹K/m› // temperature gradient
————————————————
// some calculated constants
RS = P0/T0/D0 // specific gas constant
287.053
————————————————
// calculate various combinations of the exponent values used below
PT = log(P11/P0) / log(T11/T0) // pressure to temperature
5.25587
————————————————
TP = log(T11/T0) / log(P11/P0) // the inverse
0.190263
————————————————
DT = log(D11/D0) / log(T11/T0) // density to temp or just PT-1
4.25588
————————————————
TD = log(T11/T0) / log(D11/D0) // the inverse or PT/DT-1
0.234969
————————————————
PD = log(P11/P0) / log(D11/D0) // press to density or just 1+TD
1.23497
————————————————
DP = log(D11/D0) / log(P11/P0) // or just 1-TP
0.809738
NOTE: DT is PT-1
NOTE: TD is PD-1
The others are inverses:
TP = 1/PT
TD = 1/DT
and DP is just 1-TD
All are exponents in polytropic closed-form solutions.
————————————————
// test that calculating some point returns correct values
P = P0 * (T11/T0) ^ PT
22632.1
————————————————
P = P0 * (D11/D0) ^ PD
22632.1
————————————————
D = D0 * (T11/T0) ^ DT
0.363918
————————————————
D = D0 * (P11/P0) ^ DP
0.363918
————————————————
T = T0 * (P11/P0) ^ TP
216.65
————————————————
T = T0 * (D11/D0) ^ TD
216.65
————————————————
// test at 5000‹m›
T5 = T0 – 5000*TG
255.65
————————————————
P5 = P0 * (T5/T0) ^ PT
54019.9
————————————————
D5 = D0 * (P5/P0) ^ DP
0.736116
————————————————
// test at 9000‹m›
T9 = T0 – 9000*TG
229.65
————————————————
P9 = P0 * (T9/T0) ^ PT
30742.5
————————————————
D9 = D0 * (P9/P0) ^ DP
0.466348
And you will find that all of these closed-form differential and integral of the polytropic relationships holds true for any atmosphere that we have so far been able to measure with current technology of probes and radiosondes ignoring any small noise differences due to instantaneous weather in the process of seeking equilibrium (the small wiggles in plots).
————————————————————————————–
“3. While surface pressure remains constant and lapse rate remains constant, the altitude of 15 kPa atmospheric pressure varies 2:1 from equator to poles, and 1:3 from before dawn to mid afternoon at summertime latitudes. Why?”
I don’t blindly agree with your ratios Will without some reference or example but all you really need to do is see above with a calculator and some real data measurements in hand from other atmospheres at various vertical points.
If you start out with a backwards understanding of the nature of atmospheric flow you are going to spend all your energy trying to model it. Once you have a model you will have something that will appear to have predictive power. And, thus, you will have created an obstacle that you will never be able to overcome. Never.
For example, if you build a model of planetary motion starting with the assumptions that the earth is the center of the universe . . .
. . . it won’t be until a guy like Copernicus or Galileo comes along . . .
I am that guy.
James McGinn
Solving Tornadoes
[Reply] Copernicus and Galileo showed their maths. Where’s yours?
suricat says: February 26, 2016 at 1:23 am
“This ‘is’ consistent RC. The ‘value/weight’ of a mass/massive ‘object’ is disclosed by the continued application of a ‘given’ force to the object. This (given) ‘force application’ discloses the ‘weight/mass’ of the ‘object under investigation’ by way of the rate of acceleration of the object.”
I disagree; The acceleration of mass by Earth’s gravity is independent of the value of that mass (within limits) A mass balance can indicate ratios of amounts of mass but is independent of the force of Earth’s gravity (within limits). Only a stress indicator (spring compression/elongation), with zero acceleration, can indicate Weight ∝ the product of local mass and Earth’s gravitational force.
This atmosphere can exhibit no measurable weight, as the relationship between atmosphere and Earth’s gravity is never local!
“This also ‘transposes’ as local ‘gravity constraints’ on the subject under consideration (which is compromised by ‘pressure’ [electrostatic equilibrium]). Earth’s gravity obfuscates a ‘clean’ observation IMHO by generating ‘an atmosphere’ in the first place. Best regards, Ray.”
Indeed! The all of Navier-Stokes partial differential equations, packaged neatly within 20km of the Earth,s surface for easy observation. A test to see if humans have intelligence, or must remain as stupid as they appear! The Earth’s actual atmospheric surface pressure has a measurable component (partial) ∝ to ω², the square of the Earth’s angular velocity. Tallbloke wants me to provide both calculations and the results. I have not yet discovered but a small part of the required partials, to evaluate their significance. I prefer to appear as stupid as I am!
oldbrew says: February 18, 2016 at 9:36 pm
“Wikipedia says the thermal wind is really a wind shear – but admits its ‘article has multiple issues’ and ‘needs attention from an expert in Meteorology.’ (September 2012)”
Thermal Wind is an abstraction of the illusionary “Geostrophic Wind” Both are fantasy phrases invented by academic “teachers” of meteorology so as to give the impression that the failed astrologers have understanding of how this atmosphere may work!
Stewart; you opened this can of worms, perhaps it needed to be opened! Do not expect those worms to fit back into the can. 🙂
All the best! -will-
Will Janoschka says: February 26, 2016 at 6:15 am
(Roger Clague says: February 25, 2016 at 10:37 am)
suricat says: February 26, 2016 at 1:23 am
(“When I say the point of view (POV) of each molecule is critical, I mean: 1. The motion of each molecule in a gas is random, independent, statistical, inertial and isotropic.”)
“I concur, but you’ve left out ‘penetration’ by ‘diffusion’ (yet another statistical assumption). Each molecule that alters its position within a gas mix does so by ‘diffusion’.”
Will asks: “Ray, Why such pedantic-acy? Is that a word?”
The word you’re looking for is ‘pedantry’ Will. I’m pedantic about this point because Roger Clague used the term ‘POV’ (Point Of View), which isn’t anything to do with a ‘reference frame’ other than an ‘opinion’ for/against it. 😦
Hmm. Let’s take the ‘reference frame’ to be that of a ‘given’ molecule as an example. Our molecule gets ‘kicked’ into another environment by diffusive migration. What happens to the ‘reference frame’? Its in another ‘universe’! Nothing relates to what the environment was before the molecule was ‘diffused’ elsewhere. This is nothing less than ‘chaos’ IMHO.
“You claim a single POV is sufficient. Why?”
I don’t! I say a single ‘reference frame’ is essential! From there you can take whichever ‘point of observation’ within the ‘reference frame’ that you wish to take and the ‘outcome’ can be synchronized with other observations at other points of observation within the ‘reference frame’.
A ‘Whole Earth’ gravity field, inclusive of ‘other body off-sets’, is the only ‘reference frame’ that can possibly reveal the true nature of ‘some’ of Earth’s atmospheric activity.
“My point I wish to express again, is that no one or group has the slightest clue as to how this atmosphere may work. Any claim of such must be an attempt at deliberate scam!”
That’s a ‘conspiracy theory’ in the making Will, but we have the numbers on our side. 😉
Best regards, Ray.
James McGinn says: February 26, 2016 at 7:46 pm
“If you start out with a backwards understanding of the nature of atmospheric flow you are going to spend all your energy trying to model it. Once you have a model you will have something that will appear to have predictive power. And, thus, you will have created an obstacle that you will never be able to overcome. Never.”
I concur. The ‘direction of understanding’ must be ‘forwards’ to improve any possible ‘model’ that ‘someone’ may want to construct!
However, why construct a ‘model’ for chaos? Perhaps because a ‘link’ can be achieved/understood that reveals the interaction between ‘atractor systems’ which may show the ‘deterministic’ inevitability for the/an outcome. 🙂
“For example, if you build a model of planetary motion starting with the assumptions that the earth is the center of the universe . . .
. . . it won’t be until a guy like Copernicus or Galileo comes along . . .
I am that guy.”
That’s ‘strong’ language James! Please explain yourself.
“James McGinn
Solving Tornadoes”
Your ‘sig’ suggests that you have a presence on ‘the web’. I’d appreciate a ‘link’ to this site for a better appreciation of your POV.
Best regards, Ray.
suricat says: February 29, 2016 at 3:05:
Ray: I concur. The ‘direction of understanding’ must be ‘forwards’ to improve any possible ‘model’ that ‘someone’ may want to construct!
Jim: The jet streams concentrate and conserve momentum. The energy thereof is what pulls the rest of the atmosphere along, by way of storms, which are themselves the result of down-reaching extensions of the jet streams–vortices. Moisture is intrinsic to the process because of H2O’s high surface tension which becomes maximized along wind shear boundaries. That is why storms are wet. Convection plays no role at all.
Ray: Your ‘sig’ suggests that you have a presence on ‘the web’. I’d appreciate a ‘link’ to this site for a better appreciation of your POV.
Jim: My website is currently dark until its grand re-opening in June. I’m in negotiations with a documentary film company about all of this, currently working on the script. However, you can view some of my recent web activity, and three videos, at the following site. I think my friend Mike will appreciate the traffic. Be sure to check out some of his other content:
http://scottishsceptic.co.uk/2011/08/26/how-to-get-off-the-ground-with-nothing-but-water-almost/#comment-39080
Cheers,
James McGinn
Solving Tornadoes
James McGinn says: February 29, 2016 at 5:02 am
“The jet streams concentrate and conserve momentum.”
I disagree. The ‘conservation of momentum’ is supplied by the ‘global cell’ per se. The ‘jet streams’ are the product of ‘overly energetic’ entities that can’t integrate into a ‘global cell’ (into either of the ‘polar’ cells, or [the ‘two faced/bi-hemispherical’ energy loss] of the ‘Hadley’ cell).
The ‘jets’ are ‘overspill’ IMHO.
“The energy thereof is what pulls the rest of the atmosphere along, by way of storms, which are themselves the result of down-reaching extensions of the jet streams–vortices.”
‘Jet streams-vortices’???
AFAIK the direction of the ‘jet stream’ is defined by the ‘forcing’ within the appropriate ‘global cell’. Are you putting the ‘cart before the horse’ here or are you posing an alternative solution?
“Moisture is intrinsic to the process because of H2O’s high surface tension which becomes maximized along wind shear boundaries. That is why storms are wet. Convection plays no role at all.”
Let’s get at least one thing straight! ‘Surface tension’ is only apparent in the ‘liquid’ phase of H2O!
I’ll not comment further.
Ray.
We’ve seen weightless anything nutters. Now someone who claims the atmosphere contains no watervapour.
The number of idiotic ideas that are discussed on this site is unbelievable.
And all this in what should have been a short discussion about something simple as atmospheric convection.
Perhaps better change the sites name into Tallbloke’s Madhouse?
Ben Wouters says: March 1, 2016 at 2:01 pm
“We’ve seen weightless anything nutters. Now someone who claims the atmosphere contains no watervapour.
The number of idiotic ideas that are discussed on this site is unbelievable.”
I guess you watched ‘the video’ that Jim McGinn linked to here. 😦
Yea! Some are pretty ‘far out’, but ‘plasma’, in the tropo?
Electrolytic action perhaps, but temperatures are ‘nowhere near’ high enough here, unless you consider ballistic particle physics. The energy levels are just not there! A ‘compound’ doesn’t change its ‘atomic identity’ when it undergoes a ‘change of phase/state’.
“And all this in what should have been a short discussion about something simple as atmospheric convection.”
I disagree Ben. There are so many ‘odd ball’ concepts out there that need to be formally addressed.
“Perhaps better change the sites name into Tallbloke’s Madhouse?”
No. I’ve a better name. ‘Tallbloke’s Correctional Center’ 🙂
Best regards, Ray.
suricat says:
February 28, 2016 at 12:18 am
Let’s take the ‘reference frame’ to be that of a ‘given’ molecule as an example. Our molecule gets ‘kicked’ into another environment by diffusive migration. What happens to the ‘reference frame’? Its in another ‘universe’! Nothing relates to what the environment was before the molecule was ‘diffused’ elsewhere. This is nothing less than ‘chaos’ IMHO.
The environment is isotropic in a gas. Chaos but randomly ordered chaos.
However the Earth’s atmospheric gravity environment changes by 0.3% from bottom to tropopause.
Diffusion is slow only 30cm/hr. This is enough given time to set the pressure gradient.
suricat: A ‘Whole Earth’ gravity field, inclusive of ‘other body off-sets’, is the only ‘reference frame’ that can possibly reveal the true nature of ‘some’ of Earth’s atmospheric activity.
The mass of an air molecule is gravitational and inertial. The molecule is attracted by the Earth and surrounding molecules. We agree both the Earth’s gravity and the surrounding gas gravity have an effect. The question is how to combine these effects.
The conventional way is the say Earth’s gravity causes weight and the gas itself has motion. That is 2 reference frames. The 2 balance each other in Hydrostatic equilibrium.
Kinetic theory of Gas.
The separate effect of Earth and other gas molecules can be combined by considering the effect of each on velocity of molecules, which is 1 reference frame.
Inertial mass and Earth’s gravity affect the velocity of molecules in different way
1. Gas pressure is caused by inertial mass and velocity of molecules, which causes changing momentum at collisions
2. Atmosphere pressure gradient caused by Earth’s gravity acceleration gradient changing velocity with height.
http://www.britannica.com/science/gas-state-of-matter
Excellent on what Kinetic theory of gas can calculate out of chaos.
Kinetic theory calculation of the atmospheric thermal enhancement (ATE).
v^2 = 2gs Newton’s equations of motion
g is the change in Earth’s gravity =0.003 x 10m/s
v^2 = 2 x 0.003 x 10m/s x10 000m
change in v caused by change in g= 50m/s
v at surface, 300K, = 500m/s
v1/v2 = (T1/T2)^1/2 Kinetic theory
v at 240K = 450m/s
The change in g from surface to 10 000m of 0.003g causes the change in T of 60K
Roger Clague: “The change in g from surface to 10 000m of 0.003g causes the change in T of 60K”
For you conjecture to hold any water [so to speak] you must take that thought and equation and apply it to other atmospheres, other places within some atmosphere, with different compositions, different gravitational accelerations, different radii for which we have good measurements and probe data and see if that same equation using delta gravity match their height/temperature profiles very close. On first sight. I am afraid yours fails. This is a case of classic numerology, where you have pieced and hammered together some values and equations that match, in one particular case, of values and seems to match the answer you were looking for in the first place and you plant your claim, but it fails in all other applications.
Also, your 0.003g factor depends on the delta of radii squared does it not, and temperatures do not follow that power curve within tropospheres, it is linear. That is yet one other example of why your conjecture seems to fail Roger.
I gave you, and all other commenters here, all of the equations not too far above this comment that do agree with all known tropospheres at any altitudes so it seems for you to come up with some new physics or new thermodynamics your conjectures must also conform to those relationships. Test them, just plug in the data [g, m, and the two end point T and P at the end of some (any) linear segment within some other body’s tropospheres], it holds true.
What those equations above do seem to prove is that the AGW conjecture is impossible except within one particular case. The temperature/pressure profiles for various tropospheres depends on the molecular degrees of freedom of the component gas molecules AND if the surface temperature were to ever globally rise on the average then the temperatures globally at the tropopause must also rise by the same ratio, that is, the observed mean lapse must always stay constant, and that change in lapse or warming of the tropopause is not occurring here on Earth during these time periods. AGW is not occurring. It is the sun influx or albedo, stupid [not you, but those who are the AGW proponents]. Q.E.D.
Wayne. We’ll have to do a post on your equations soon. Have a think about fleshing it all out with some plots of planetary atmospheres.
O.K., all for it! My time at the moment is a bit limited, so might take a week or two, but I’d love to put that all together in one long post for all to consider what all of the other atmospheres as a group seem to be telling us, what is and what is not. As for the exact why, physically… I am still myself at a loss for a satisfactory explanation but that is what the data from the probes is telling us or that seems so.
wayne says:
March 2, 2016 at 4:29 pm
For you conjecture to hold any water [so to speak] you must take that thought and equation and apply it to other atmospheres
Good point.
g for Earth and Venus is similar. The Venus atmosphere tropopause is 90Km that is 9 x Earth.
So I expect x9 ATE of Earth for Venus.
That is 9 x 60K = 540K.
ATE Venus = 750K surface – 200K tropopause = 550K
Wayne: Also, your 0.003g factor depends on the delta of radii squared does it not, and temperatures do not follow that power curve within tropospheres, it is linear.
g/h is almost linear up to 100km.
wayne says:
February 26, 2016 at 7:10 pm
Please give a reference to the atmosphere equations you use and how they are produced.
suricat says: March 2, 2016 at 1:20 am
“Electrolytic action perhaps, but temperatures are ‘nowhere near’ high enough here, unless you consider ballistic particle physics.”
To me ballistic particle physics is the underlying mechanism to explain the hydrostatic equlibrium in an atmosphere. (without claiming any deep knowledge of the subject).
Between collisions all particles are on a ballistic trajectory. The ones that move straight up decelerate with ~9,81 m/s^2, the ones going straight down accelerate with the same rate.
The ones moving away horizontally will see their trajectory turn towards the surface, exactly like a bullet or similar would.
So the average molecule in the atmosphere has a downward component in its trajectory, accelerating towards the surface with 9,8 m/s^2 before being ‘kicked’ into the next trajectory, thus creating the downward pressure equal to the weight of the column above.
Idiotic ideas about the atmosphere being “in orbit” are far away from reality. Orbital speed near the surface would be ~7900 m/s. Average molecular speed for air at surface temps ~500 m/s.
Roger Clague says: March 2, 2016 at 12:12 pm
“http://www.britannica.com/science/gas-state-of-matter
Excellent on what Kinetic theory of gas can calculate out of chaos.”
In that article:
Assuming the environment to be ~ a vacuum, the piston moving without friction and no air escaping along the piston, the weight to contain the pressure below the piston for a 1 m^2 area piston would be ~ 10.000 kgf for normal atmospheric surface pressure.
How do you expect the atmosphere to be held on the surface with only weightless air between the surface and the deep vacuum of space?
Roger Clague says: March 2, 2016 at 12:12 pm
“The environment is isotropic in a gas. Chaos but randomly ordered chaos.”
Only ‘isotropic’ in a ‘perfect gas’ RC. A ‘gas mix’ usually contains many anomalies when observing Earth’s atmosphere.
“However the Earth’s atmospheric gravity environment changes by 0.3% from bottom to tropopause.”
No, that’s the differential to ‘gravity forcing’ for that altitude change. The ‘force of gravity’ is altered ‘more’ by the ‘change in latitude’ for ‘Earth’s centrifuge’ (Coriolis effect) than this altitude measurement (~3 ins/sec^2 in counterpoise to gravity at equatorial observation).
“Diffusion is slow only 30cm/hr. This is enough given time to set the pressure gradient.”
This is an ‘approximation’ for an ‘average molecule’ in an ‘average gas’ (perfect gas). The ‘energetic’ and ‘inertia value’ determine the ‘depth of penetration’ for each and every molecule.
If an individual poured petroleum spirit on the floor of a garage twenty feet away from me, it wouldn’t take an hour before I could smell it!
“The mass of an air molecule is gravitational and inertial. The molecule is attracted by the Earth and surrounding molecules. We agree both the Earth’s gravity and the surrounding gas gravity have an effect. The question is how to combine these effects.”
Whilst I concur that the ‘atmospheric gravitational forcing between molecules’ is ~negligible. The main thrust of ‘gravity’ is towards the ‘Earth centric’ ‘Barry center’ for Earth. There is just ‘so much more mass’ there!
Its OK to take a ‘molecular’ ‘reference frame’ for a ‘well mixed gas’ within a ‘solid confinement’ region, but this doesn’t work well for an ‘atmosphere’ where a ‘well mixed gas’ can’t be expected. 🙂
“The conventional way is the say Earth’s gravity causes weight and the gas itself has motion. That is 2 reference frames. The 2 balance each other in Hydrostatic equilibrium.”
No RC. These are degrees of freedom!
We ‘need’ a ‘reference frame’ to ‘relate’ the ‘degrees of freedom’ to!
I’ll not post more just now. 😦
best regards, Ray.
Roger Clague says: March 2, 2016 at 12:12 pm
I’ll take another shot at this, though I write in ‘the small hours’ as I can’t see a window in the near future.
“Kinetic theory of Gas.
The separate effect of Earth and other gas molecules can be combined by considering the effect of each on velocity of molecules, which is 1 reference frame.”
Disagree. The ‘kinetic’ property consists of ‘other’ variant energetics for an atmosphere. Latitudinal definition is the ‘first’ objection that comes to mind.
“Inertial mass and Earth’s gravity affect the velocity of molecules in different way”
As does the ‘advection’ component mentioned in my ‘first objection’ above.
“1. Gas pressure is caused by inertial mass and velocity of molecules, which causes changing momentum at collisions”
I don’t know where to start here. I’ll try this.
‘Pressure’ is a ‘construct’ that arises from the ‘compression’ of the electrical ‘static repulsion’ that exists between molecules and is due to the ‘forced confinement’ of molecules that have been ‘energised’ into a ‘~gaseous state’.
Thus, ‘pressure’ (WRT an atmosphere/gas [which also contains some liquids]) has the freedom of ‘compressibility’ as a variant to alter its volumetric measurement for ‘compressibility’.
Moreover, there’s no mention of ‘advection’ by ‘Earth rotation’ that ‘varies’ the effective application of Earth’s ‘gravity field’.
Enough.
“2. Atmosphere pressure gradient caused by Earth’s gravity acceleration gradient changing velocity with height.”
NO WAY! The ‘overburden’ of the atmosphere’s ‘apparent weight’ generates this phenomenon, but its modified by the level/type of insolation received.
I’ve little/no interest in what ‘britannica.com’ has to say, so I’ll leave this now.
I’m off to bed. 🙂
Ray.
Ben Wouters says:
March 3, 2016 at 2:25 pm
So the average molecule in the atmosphere has a downward component in its trajectory, accelerating towards the surface with 9,8 m/s^2
The average molecule is accelerating upwards as often as downwards.
before being ‘kicked’ into the next trajectory, thus creating the downward pressure equal to the weight of the column above.
Yes the downward component of air pressure causes a downward force equal to the downward force created by the weight of a column of, for example, Hg. That does not prove the air pressure is also caused by weight mg.
All the forces on the molecules in a gas are caused by velocity which acts on mass to cause momentum mv.
BW: the weight to contain the pressure below the piston for a 1 m^2 area piston would be ~ 10.000 kgf for normal atmospheric surface pressure.
This is the Bernoulli model 1738 and now called hydrostatic equilibrium.
This model was replaced by Kinetic Statistical Mechanics of Gas inn late19C.
The diagram shows 1m^3 of air at normal T and p, STP. Mass of 1m^3 of air at STP is 1kg.
According to you pressure is caused by weight. At the bottom of the vessel pressure will be 11kgf.
That is 10% more at the bottom of the vessel than 1 m higher up. This does not happen. The pressure will be the same anywhere in the 1m^3 volume.
The model shown in the diagram, the Hydrostatic Equilibrium model is wrong.
BW: How do you expect the atmosphere to be held on the surface with only weightless air between the surface and the deep vacuum of space?
The atmosphere is
1. not held
2. not on the surface
The atmosphere gains gas from the Earth and plants and loses gas to space. The mass of an atmosphere changes. For example, there was more CO2 in dinosaur age. The atmosphere is many km. thick
The atmosphere is retained by Earth’s gravity. Earth’s gravity acts by slowing molecules and reducing their tendency to escape to space.
Because pressure depends on v, and v depends on sqrt T the p/h curve is exponential.
N2 velocity is 500m/s^2 at surface 290K and 450m/s^2 at 10km 220K.
[Reply] “Caused by velocity”. Velocity is a measurement of position with respect to time within a reference frame. It does not “cause” anything.
suricat says: March 4, 2016 at 3:05 am
“The ‘force of gravity’ is altered ‘more’ by the ‘change in latitude’ for ‘Earth’s centrifuge’ (Coriolis effect) than this altitude measurement (~3 ins/sec^2 in counterpoise to gravity at equatorial observation).”
This comment plus re-reading https://tallbloke.wordpress.com/2015/06/11/atmospheric-convection-what-does-it-mean/comment-page-1/#comment-102759
makes it abundantly clear that you have no idea what the Coriolis effect actually is.
Try ttp://www.recreationalflying.com/tutorials/meteorology/section1b.html#atmospheric_momentum
for a simple explanation and
https://en.wikipedia.org/wiki/Coriolis_force#Meteorology for a more comprehensive version.
Roger Clague says: March 7, 2016 at 10:18 am
“The average molecule is accelerating upwards as often as downwards.”
ACCELERATING upwards???
What accelerates these molecules up against gravity? Little jet engines or rocket motors perhaps?
“The model shown in the diagram, the Hydrostatic Equilibrium model is wrong.”
The model does NOT show hydrostatic equlibrium. It just shows the weight required to CONTAIN normal surface pressure in a closed box with a movable piston.
Or are you now claiming that pressure (caused by the collisions of molecules/atoms) does NOT cause a force on the walls of a container?
“The diagram shows 1m^3 of air at normal T and p, STP. Mass of 1m^3 of air at STP is 1kg.
According to you pressure is caused by weight. At the bottom of the vessel pressure will be 11kgf.”
In this example the pressure against the top of the container (1 m^2) is ~10.000 kgf. On the bottom it will be ~10.000 +1 kgf.
“The atmosphere is
1. not held
2. not on the surface”
Where do we find a vacuum on the surface in the absence of atmosphere?
Ben, thanks for taking over for a while. Roger C repetitively returning to the same fallacies even after being forced to admit them has made me step away before I ban him for this continual groundhog day nonsense..
Ben Wouters says:
March 7, 2016 at 2:54 pm
RC: “The average molecule is accelerating upwards as often as downwards.”
BW: ACCELERATING upwards???
What accelerates these molecules up against gravity?
RC:The weight in the diagram is being supported by the force caused by the change of momentum of the molecules hitting the piston. Change of momentum needs acceleration and deceleration.
[Reply] Upwardly moving air molecules are already decelerating due to gravity. That’s Ben’s point. A point you try to evade with twisty argument. The fact they are decelerating doesn’t prevent them having momentum, but that momentum is decreasing with altitude, which is how Earth’s gravity retains Earth’s atmosphere. TB
Change of momentum is also caused by close approach of molecules causing electrostatic repulsion
RC: “The model shown in the diagram, the Hydrostatic Equilibrium model is wrong.”
BW: It just shows the weight required to CONTAIN normal surface pressure in a closed box with a movable piston.
RC: The diagram shows air pressure caused by weight and motion of molecules.
The Hydrostatic Equilibrium Theory says weight of air balances molecular motion of air.
BW: “The diagram shows 1m^3 of air at normal T and p, STP. Mass of 1m^3 of air at STP is 1kg.
According to you pressure is caused by weight. At the bottom of the vessel pressure will be 11kgf.”
In this example the pressure against the top of the container (1 m^2) is ~10.000 kgf. On the bottom it will be ~10.000 +1 kgf.
The pressure inside the box at the top is 10Kgf. The pressure inside the box at the bottom is 11Kgf.
This will not happen as the pressure in a sealed box would be equal at top and bottom.
So the model is wrong.
BW: Where do we find a vacuum on the surface in the absence of atmosphere?
Absence of an atmosphere is a vacuum.
tallbloke says:
March 7, 2016 at 11:32 pm
Roger C’c repetitive returning to the same fallacies
I say air has no weight. Therefore weight of air does not cause air pressure.
By “has weight” I mean does what solid and liquids do. That is cause an observable effect on a vertically arranged force meter.
I have asked for evidence of weight of air.
The evidence suggested is:
1. Increase in weight when more mass of air is pumped into a ball.
2. The increase in weight when air fills a vacuum in a glass flask.
In both there is an increase in pressure which I say causes the increased down force.
3. Air pressure in an Hg barometer can supports the weight of a column of Hg.
The barometer only measures the downward component of air pressure.
My opinion is not popular but what is false and why?
[Reply]” there is an increase in pressure which I say causes the increased down force.”
You’ve already agreed this is due to gravity acting on the mass of the air molecules. Gravity acts on mass. “Weight” is a secondary property involving other factors such as buoyancy. Scientists don’t use “weight”, they talk about mass. Come back when you are ready to talk about science.
Ben Wouters says: March 7, 2016 at 2:42 pm
Incomplete link:
Try http://www.recreationalflying.com/tutorials/meteorology/section1b.html#atmospheric_momentum
for a simple explanation and
https://en.wikipedia.org/wiki/Coriolis_force#Meteorology for a more comprehensive version.
tallbloke says: March 7, 2016 at 11:32 pm
Well, as long as you allow every idiotic idea to be promoted and discussed ad nauseam understanding of something simple and basic as atmospheric convection will never be reached.
Let alone a useful discussion of how this atmosphere really works.
Roger Clague says: March 8, 2016 at 3:24 pm
“The pressure inside the box at the top is 10Kgf. The pressure inside the box at the bottom is 11Kgf.
This will not happen as the pressure in a sealed box would be equal at top and bottom.”
Are you aware that normal atmospheric surface pressure is around 1 kgf/cm^2?
Are you aware that 1 m^2 is 10000 cm^2?
So where does this 10 kgf pressure inside the box come from, given that I specified normal atmospheric surface pressure?
Quote: An illustration of the Barometric Law is the sea-breeze circulation commonly observed at the beach on summer days.
See: 2.5 THE SEA-BREEZE CIRCULATION
http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap2.html#27009
Circulation cell (c)
Figure 2-4 The sea-breeze circulation
Ben Wouters says: March 7, 2016 at 2:42 pm
“suricat says: March 4, 2016 at 3:05 am
“The ‘force of gravity’ is altered ‘more’ by the ‘change in latitude’ for ‘Earth’s centrifuge’ (Coriolis effect) than this altitude measurement (~3 ins/sec^2 in counterpoise to gravity at equatorial observation).”
This comment plus re-reading https://tallbloke.wordpress.com/2015/06/11/atmospheric-convection-what-does-it-mean/comment-page-1/#comment-102759
makes it abundantly clear that you have no idea what the Coriolis effect actually is.”
Why do you say this Ben? My understanding of the ‘Coriolis effect’ isn’t ‘absolute’, but I think its good!
“Try ttp://www.recreationalflying.com/tutorials/meteorology/section1b.html#atmospheric_momentum
for a simple explanation and
https://en.wikipedia.org/wiki/Coriolis_force#Meteorology for a more comprehensive version.”
I’ve visited your first link on more than one occasion, but your second link is suspicious by way of its ‘editable’ content. Perhaps the ‘page’ is under construction. Its ‘content’ is ‘inaccurate’.
‘Coriolis’, per se, ‘isn’t’ a ‘force’. Its an ‘effect’ produced by ‘other forces’ that act in a ‘given configuration’.
Do you understand the difference between ‘planar’ and ‘radial’ turbines yet? If not, let me expound.
A ‘turbine’ is a ‘mechanical construct’ that converts the ‘energy’ of a ‘natural construct’ into the ‘energy’ of another ‘energetic field’, or vice versa.
The ‘field’ under observation should be ‘inertia’.
Yes, I’m still ‘there for you’, but you need to ‘rationalise your objectivity’ between the ‘macroscopic’ and ‘microscopic’ POV. These ‘variant’ POVs are confusing between one-another.
Please forgive me if my response is slow. A ‘close friend’ has problems with lung cancer and ‘other’ issues.
Best regards, Ray.
oldbrew says: March 9, 2016 at 2:17 pm
“Figure 2-4 The sea-breeze circulation”
Well known mechanism, exactly the same as that drives the Hadley circulation etc.
No convection involved nor required.
suricat says: March 11, 2016 at 1:54 am
“Why do you say this Ben?”
Because you continuously speak of the Coriolis effect as if it is relevant in the vertical axis.
It isn’t. The centrifugal force due earths rotation, Eötvös effect etc. cause a TINY reduction in the local gravity, and can be neglected in most situations because hydrostatic equlibrium takes care of these tiny differences.
The Coriolis effect works on any mass that MOVES over the rotating earth.
An air mass, water mass, train etc. that MOVE from eg the equator northbound will turn to the right due to the conservation of momentum. At the equator they move with the surface at ~465 m/s. Further north the rotational speed of the surface is lower, and the masses APPEAR to be forced to turn to the right. THIS is the Coriolis effect.
Ben Wouters says: March 11, 2016 at 1:57 pm
““Figure 2-4 The sea-breeze circulation”
Well known mechanism, exactly the same as that drives the Hadley circulation etc.
No convection involved nor required.”
??? Surely, this ‘is’ temperature change and density disparity at its best?
Best regards, Ray.
Ben Wouters says: March 11, 2016 at 2:09 pm
No Ben, that’s the ‘effect’ at the ‘surface’! The ‘Coriolis effect’ to ‘the atmosphere’ is more profound. I’ll search for a good graphic that can visually show this and add comment in an attempt to explain it.
However, its nice to know that you comprehend the laws of ‘conservation of momentum’.
Best regards, Ray.
oldbrew says:
March 9, 2016 at 2:17 pm
Quote: An illustration of the Barometric Law is the sea-breeze circulation commonly observed at the beach on summer days.
See: 2.5 THE SEA-BREEZE CIRCULATION
http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap2.html#27009
This is a strange explanation of sea-breeze circulation. It is normally seen as differential heating at the surface causing pressure differences. This phenomenon in no way illustrates or supports the theory which leads to the derivation of the so-called Barometric Law.
The reference is a concise derivation of the Barometric Formula
I find it unconvincing because of
1. Lack of a physical theory,
2. Unjustified assumptions
3. Dodgy algebra
2.1 MEASURING ATMOSPHERIC PRESSURE
The atmospheric pressure is the weight exerted by the overhead atmosphere on a unit area of surface.
The atmosphere has no weight. I am not aware of the evidence of the weight of any amount of any gas
As a chemist I find the amount of a gas from p,v and T
Air pressure is exerted in all directions not only downwards as does weight.
The pressure PA at point A is that of the mercury column overhead, while the pressure PB at point B is that of the atmosphere overhead.
Torricelli 1644 started this idea of air pressure caused by weight. He wrote about living under a sea of air.
Pressure at A is caused by weight of a liquid that is only downwards. The pressure at B is the downward component of gas pressure which acts in all directions. The conclusion that gas pressure is caused by weight is not justified.
2.2 MASS OF THE ATMOSPHERE
I notice there is no claim to calculate the weight of the atmosphere
2.3 VERTICAL PROFILES OF PRESSURE AND TEMPERATURE
The P/h has been made into a straight line. This conveniently obscures the fact that P/h and T/h are different in shape. They would be the same if the gas Law applied to the atmosphere.
2.4 BAROMETRIC LAW
“the pressure-gradient force is directed upwards.”
No physical cause of this force is suggested. No reason is suggested why is directed upward.
In my opinion is assumed only upwards to balance the downwards weight
If the pressure-gradient force is caused by molecular motion then any forces will be in all directions.
“We now make the simplifying assumption that T is constant with altitude; as shown in Figure 2-2 , T varies by only 20% below 80 km. “
From Fig. 2.2 I see a 90K variation.
Taking this to mean variation of the original 210K. That is 90/210 = 43%, not 20%
Being generous and taking variation of the average 255K that is 90 /255 = 36%.
We are asked to ignore a 36% variation In T and not explain it. As John McEnroe used to say, “You cannot be serious”.
According to the gas law, which is used, T should be directly proportional to p that is exponential and not constant.
And another thing why is dp an infinitesimal used and not simply p1 and p2? Gas is made of molecules which are not infinitely thin.
Why is integration called “is equivalent to”?
I did however approve of this:
“Gravitational separation of the air mixture takes place by molecular diffusion”
Because I think gravity acts on molecules in other ways than via weight.
suricat says: March 12, 2016 at 1:22 am
“??? Surely, this ‘is’ temperature change and density disparity at its best?”
See
What do you not agree with / understand about the formula under (b)?
P land (z) > P sea (z) => high-altitude flow from land to sea
suricat says: March 12, 2016 at 1:37 am
“No Ben, that’s the ‘effect’ at the ‘surface’!”
Do you actually believe that jet streams are a surface phenomenon???
The Coriolis effect is the reason that the large jet stream bands flow from west to east,
eg AHEAD of the rotation of the surface!!!!!!
suricat says: March 12, 2016 at 1:37 am
Vis:
https://climate.ncsu.edu/edu/k12/.coriolis
This may help, as there are links to other aspects.
Best regards, Ray.
Roger Clague says: March 12, 2016 at 10:46 am
“This is a strange explanation of sea-breeze circulation. It is normally seen as differential heating at the surface causing pressure differences. This phenomenon in no way illustrates or supports the theory which leads to the derivation of the so-called Barometric Law.”
I concur.
“2.1 MEASURING ATMOSPHERIC PRESSURE
The atmospheric pressure is the weight exerted by the overhead atmosphere on a unit area of surface.
The atmosphere has no weight. I am not aware of the evidence of the weight of any amount of any gas
As a chemist I find the amount of a gas from p,v and T
Air pressure is exerted in all directions not only downwards as does weight.
The pressure PA at point A is that of the mercury column overhead, while the pressure PB at point B is that of the atmosphere overhead.”
Again, I concur (I’ll skip a bit because ‘PV=N Rt’ is for an impenetrable boundary).
“According to the gas law, which is used, T should be directly proportional to p that is exponential and not constant.
And another thing why is dp an infinitesimal used and not simply p1 and p2? Gas is made of molecules which are not infinitely thin.
Why is integration called “is equivalent to”?
I did however approve of this:
“Gravitational separation of the air mixture takes place by molecular diffusion”
Because I think gravity acts on molecules in other ways than via weight.”
Yet again I find myself in concurrence with this concern for ‘definition’ Roger. Perhaps ‘pressure’ per se should be held to account?
Gas molecules are attracted by ‘gravity’, but this is a ‘weak force’ with a great distance of ‘teleconnection’. However, ‘electrostatic repulsion’ is a ‘strong force’ with a short distance of ‘teleconnection’.
To me this would imply that molecules will/shall ‘cluster’ under the ‘force of gravity’, but are repelled by their ‘close proximity’ from/by the ‘electrostatic force’ that the ‘particular molecule type’ possesses (unfortunately this ‘widens the field’ of/for ‘definition’).
The ‘mass of the molecule’ and the ‘strength of electrostatic field’ determines the ‘density’ of the gas IMHO.
IOW, the ‘gas law’ is derived from a ‘standard atmosphere’ constrained by an ‘impenetrable boundary’ and doesn’t fit well with an atmosphere.
Best regards, Ray
Ben Wouters says: March 13, 2016 at 2:48 pm
“What do you not agree with / understand about the formula under (b)?
P land (z) > P sea (z) => high-altitude flow from land to sea”
Nothing, other than the point of observation!
Day time ‘on shore breeze’ and night time ‘off shore breeze’ is well documented for surface observation. However, the ‘inertia’ generated by this ‘must’ evoke an ‘opposite wind direction’ elsewhere (at altitude).
Please realise that the ‘formula’ at “(c)” is ‘regional’ to a ‘land/sea’ interface.
Best regards, Ray.
Ben Wouters says: March 13, 2016 at 2:52 pm
“Do you actually believe that jet streams are a surface phenomenon???”
No. However, the ‘surface interaction’ with the atmosphere is what ‘drives’ the ‘west to east inertia’ which gives rise to the energetic molecules that ‘can’t mix’ with the Ferrel, or Polar, cells because of their ‘energetic vector’.
“The Coriolis effect is the reason that the large jet stream bands flow from west to east,
eg AHEAD of the rotation of the surface!!!!!!”
Yes! Just like an ice-skater that ‘pirouettes’ using their arms to control their ‘rate of spin’!
Google ‘centrifuge’!
Best regards, Ray.
suricat says:
March 16, 2016 at 3:28 am
the ‘gas law’ is derived from a ‘standard atmosphere’ constrained by an ‘impenetrable boundary’ and doesn’t fit well with an atmosphere.
My objection to applying the gas law to the atmosphere is not lack of an impenetrable boundary. Gas pressure is mainly caused by other gas molecules not the boundary.
My objection is that pressure and temperature vary vertically within the atmosphere. The gas law can only be applied where there is one pressure and one temperature at any one time. At another time there may be a different pressure and temperature. P1/T1 = P2/T2
T varies vertically to the tropopause by 36%. In the theory of hydrostatic equilibrium the gas law is used and T is assumed to be constant.
Also the problem of the stable vertical variation of T in the atmosphere cannot be avoided by considering it as separate layers, with the law applied to a layer with average temperature. . The gas law must be applied to the whole thermodynamic system, the whole atmosphere at any one time.
Roger C: Gas pressure is mainly caused by other gas molecules not the boundary.
You’ve already agreed the variation in pressure with height is caused in part by the effect of gravity on the mass of the atmosphere.
T varies vertically to the tropopause by 36%
And the amount of atmospheric mass above the tropopause compared to the amount of atmospheric mass above the surface varies by considerably more than 36%
suricat says: March 17, 2016 at 2:39 am
“Day time ‘on shore breeze’ and night time ‘off shore breeze’ is well documented for surface observation. However, the ‘inertia’ generated by this ‘must’ evoke an ‘opposite wind direction’ elsewhere (at altitude).”
This clearly shows you are absolutely clueless about what Hydrostatic Equilibrium is all about.
You even have cause and effect completely backwards.
see https://tallbloke.wordpress.com/2015/06/11/atmospheric-convection-what-does-it-mean/comment-page-8/#comment-113834
“Ben Wouters says:
February 16, 2016 at 3:06 pm
tallbloke says: February 16, 2016 at 1:03 pm
“Let me refer you again to how much difference temperature makes to pressure at surface and altitude:”
BW: Temperature makes NO difference on the surface pressure at all.
Assuming same gravity and column mass the surface pressure will be exactly the same, whether the surface temperature is -50C or + 50”
suricat says: March 17, 2016 at 3:07 am
No use having a discussion on the Coriolis effect as long as you don not understand what Hydrostatic Equilibrium is all about.
Tallbloke says:
March 17, 2016 at 1:40 pm
Roger C: Gas pressure is mainly caused by other gas molecules not the boundary.
TB: You’ve already agreed the variation in pressure with height is caused in part by the effect of gravity on the mass of the atmosphere.
RogerC: _Gas pressure is caused by other molecules.
Gas pressure varies in the 10km thick troposphere because of the variation in Earth attraction
Roger C: T varies vertically to the tropopause by 36%
TB: And the amount of atmospheric mass above the tropopause compared to the amount of atmospheric mass above the surface varies by considerably more than 36%
Roger C: Not sure what you mean.
mass above the surface I take to be total mass of atmos, m(total)
mass above tropopause I assume m(total)- m( troposphere)
Comparing them = m (total)/m (total) – m (troposphere)
This is constant because m (total) and m (troposphere) are both constant.
Roger Clague says: March 17, 2016 at 12:58 pm
“My objection to applying the gas law to the atmosphere is not lack of an impenetrable boundary. Gas pressure is mainly caused by other gas molecules not the boundary.”
I disagree. The ‘gas law’ (I assume ‘the kinetic theory of gasses’) deals with the ‘inertial properties’ of ‘gaseous fluids’ and doesn’t deal with the ‘space’ in between the ‘molecules’. Thus, ‘P’ and ‘T’ are ‘set’ and unchanging. If we make a ‘deep space’ observation we find that ‘P’ = +infinitely small and ‘T’ = molecular inertia.
We need a ‘workaround’ for this problem between ‘macroscopic’ and ‘microscopic’ observation.
“Also the problem of the stable vertical variation of T in the atmosphere cannot be avoided by considering it as separate layers, with the law applied to a layer with average temperature. . The gas law must be applied to the whole thermodynamic system, the whole atmosphere at any one time.”
I concur (see the above). We need a ‘microscopic’ representation for/of ‘pressure’ to leave only ‘one’ variable for a recognisable definition of ‘temperature’. Why? Because ‘temperature’ can always be observed by, if not a ‘thermal monitor’, the ‘molecular kinetic’.
Should this ‘pressure’ proxy be the ‘atmospheric dielectric field’? What else could disclose the ‘molecular spacing’ of the/an atmosphere? This has ionisation problems.
Best regards, Ray.
Rog (tallbloke), sorry, but after following the recent comments here I must currently reject your offer to post what I seem to have discovered applying to the probe data of all linear lapse tropospheres. To adhere to proper science, I must refrain from stepping into this pseudo-science mire evident here. Will be instead contacting you soon via e-mail for some better venue, possibly one with stricter moderation.
Ben Wouters says: March 17, 2016 at 6:07 pm
“suricat says: March 17, 2016 at 2:39 am
“Day time ‘on shore breeze’ and night time ‘off shore breeze’ is well documented for surface observation. However, the ‘inertia’ generated by this ‘must’ evoke an ‘opposite wind direction’ elsewhere (at altitude).”
This clearly shows you are absolutely clueless about what Hydrostatic Equilibrium is all about.
You even have cause and effect completely backwards.
see https://tallbloke.wordpress.com/2015/06/11/atmospheric-convection-what-does-it-mean/comment-page-8/#comment-113834 ”
Ben. Its hard to rationalise the low columnar mass at the ‘eye’ of a hurricane against the columnar mass 20 miles away from it without involving much more data representing inertia and vortexes. However, if we do go through this we may be able to add weight to the argument for a macroscopic observation of HE, but I doubt this would aid the microscopic POV.
HE becomes hard to defend when an atmosphere is always in motion, even if you accept the ‘dynamics’ as ‘constant’ (when they’re not).
Best regards, Ray.
Ben Wouters says: March 17, 2016 at 6:09 pm
“suricat says: March 17, 2016 at 3:07 am
No use having a discussion on the Coriolis effect as long as you don not understand what Hydrostatic Equilibrium is all about.”
Not so Ben. HE is an idealised ‘equilibrium’ towards which a planetary atmosphere’s energetics have a tendency to fall towards. Its an ‘atractor’, by definition, that ‘sinks’ all dynamical aberrations towards an ‘equilibria’ constant.
Coriolis is the ‘effect’ and ‘inertia’ is the ‘force’.
Best regards, Ray.
suricat says: March 20, 2016 at 2:06 am
“HE becomes hard to defend when an atmosphere is always in motion, even if you accept the ‘dynamics’ as ‘constant’ (when they’re not).”
Shows you still have no idea what HE actually is all about.
The total atmospheric column above each square meter on this planet is in HE almost all of the time. Some surface heating may warm the lowest part of the column, which will expand a little and HE is restored. Some cooling and the column will contract a little, but still in HE.
The balance (HE) is between the upward pressure gradient force and downward gravitational force.
Wind (~horizontally moving air) is a compensation between areas with different HE’s.
” Its hard to rationalise the low columnar mass at the ‘eye’ of a hurricane against the columnar mass 20 miles away from it without involving much more data representing inertia and vortexes.”
Trying to run before you can walk. First understand the simple sea breeze as shown above.
Next high and low pressure areas where the Coriolis effect plays its role.
Hurricanes are in a class of their own.
Ben Wouters says:
March 23, 2016 at 3:03 pm
Some surface heating may warm the lowest part of the column, which will expand a little and HE is restored. Some cooling and the column will contract a little, but still in HE.
The balance (HE) is between the upward pressure gradient force and downward gravitational force.
I understand that you say: downward gravitational force is caused by weight.
What causes the upward pressure gradient force?
BW: Wind (~horizontally moving air) is a compensation between areas with different HE’s.
https://en.m.wikipedia.org/wiki/Wind#Causes_of_wind
“Wind is caused by differences in the atmospheric pressure.”
RogerC: You have replaced atmospheric pressure with Hydrostatic Equilibrium (HE).
That is you are assuming HE causes air pressure.
The existence of wind (including sea breezes) does not support or prove the theory that air pressure is caused by Hydrostatic Equilibrium.
Ben Wouters says: March 23, 2016 at 3:03 pm
“suricat says: March 20, 2016 at 2:06 am
“HE becomes hard to defend when an atmosphere is always in motion, even if you accept the ‘dynamics’ as ‘constant’ (when they’re not).”
Shows you still have no idea what HE actually is all about.”
I prepared a post, but lost it when I ‘shut down’ my notebook instead of selecting ‘sleep’. Here’s a precis of what I can remember.
1) HE defines the ‘equilibrium’ for a ‘physically/impenetrably bounded’ system. The ‘atmosphere’ is bounded by a ‘flexible’ force that shares atractors that lead to ‘other’ sinks of the applied energy (KE follows the ‘route of least resistance’ towards entropy).
2) For an ‘open system’ (an atmosphere) the boundary is only ‘vertical’.
If ‘HE’ was a ‘main programme’, the ‘sub routines’ would be multifarious.
“The total atmospheric column above each square meter on this planet is in HE almost all of the time. Some surface heating may warm the lowest part of the column, which will expand a little and HE is restored. Some cooling and the column will contract a little, but still in HE.”
You describe a ‘conventional convection’, but ‘other’ forcings are at work above the ‘boundary level’.
“The balance (HE) is between the upward pressure gradient force and downward gravitational force.”
No! Inertia is involved.
“Wind (~horizontally moving air) is a compensation between areas with different HE’s.”
Only from a ‘surface’ POV!
That’s all for now.
Best regards, Ray.
suricat says: March 27, 2016 at 4:59 am
“You describe a ‘conventional convection’”
Outside the UK this is called Thermal Expansion.
https://en.wikipedia.org/wiki/Thermal_expansion
““ (BW) The balance (HE) is between the upward pressure gradient force and downward gravitational force.”
No! Inertia is involved.”
We have been through this long ago. Here we go again:
Outward centrifugal effect due inertia at the equator opposes the downward effect of gravity.
(this is for air that is static relative to the surface)
Combined forces result in an Effective (apparent) gravity that is 0,3% lower at the equator than at the poles. This tiny difference has long ago been equalized by a little more column mass near the equator relative to the poles. The effect can safely be ignored for everyday use.
https://en.wikipedia.org/wiki/Gravity_of_Earth#Latitude
Inertia for air that MOVES relative to the surface results in the Coriolis effect.
Ben Wouters says:
March 29, 2016 at 10:14 am
Combined forces result in an Effective (apparent) gravity that is 0,3% lower at the equator than at the poles. This tiny difference has long ago been equalized by a little more column mass near the equator relative to the poles
Gravity is 0.3% lower at the equator than the poles because the equator is further from the center of gravity. This difference is not equalized by the atmosphere mass or anything else.
Most mass of the atmosphere in the troposphere. The height of troposphere and hence the column mass is two times more at the equator than the poles. The difference in column mass at the equator and poles is x2 not 0.03%.
Troposphere height and column mass is caused by the different distance to the tropopause which has a constant temperature
Ben Wouters says: March 29, 2016 at 10:14 am
“suricat says: March 27, 2016 at 4:59 am
“You describe a ‘conventional convection’”
Outside the UK this is called Thermal Expansion.”
No it isn’t when you speak of ‘atmospheric activity’ for the, all encompassing, Hadley cells. Your description reads as an expansion of gas within a region of a ‘fixed enclosure’. Data (and datum’s [not to mention atractors]) are missing (did I just say ‘atractors’?)!
“““ (BW) The balance (HE) is between the upward pressure gradient force and downward gravitational force.”
No! Inertia is involved.”
We have been through this long ago. Here we go again:
Outward centrifugal effect due inertia at the equator opposes the downward effect of gravity.
(this is for air that is static relative to the surface)
Combined forces result in an Effective (apparent) gravity that is 0,3% lower at the equator than at the poles. This tiny difference has long ago been equalized by a little more column mass near the equator relative to the poles. The effect can safely be ignored for everyday use.”
“Everyday use” ‘for a weather forecast’ isn’t being discussed here Ben, but ‘atmospheric convection’ is. Please be mindful of this.
Yes we’ve been through the ‘centrifugal effect’, the ‘diffusion effect’ and the ‘delta T effect’ before. What is it that troubles you the most with atmospheric convection?
You’ve been a bit mean with your “0,3% lower at the equator than at the poles” figure. 32 ft/sec^2 (gravity constant) – ~3 in/sec^2 (gravity ‘counterpoise’) is a lot closer to 1% than your estimation. However, that isn’t the issue. Its only an ‘aside’ that reinforces the principle of ‘other than temperature mediated convection’. Diffusion by H2O is a greater influence, but Earth’s ‘centrifuge’ should be recognised for its effect.
H2O always ‘evaporates’, even at the frozen polar regions (this leads into ‘diffusion’). This ‘phase change’ generates a ‘lighter than air’ gas, WV (Water Vapour)! However, the ‘rate’ that WV is generated is ~dependant on the regional average temperature for that region (~when/where water is evident).
‘Elevated temperature’ reads, or can read, as ‘elevated ‘SH’ (specific humidity) WRT ‘RH’ (relative humidity).IOW, a ‘constant global RH’ leads to a divergent regional ‘SH’ globally dependant on the temperature of the ‘region/latitude’.
WV ‘diffuses’ the atmosphere to a ‘greater altitude’ near the ITCZ more than it does at regions away from this latitude.
Both Earth’s centrifuge and H2O’s diffusion influence lead to the establishment of a/the ‘Hadley cell/s’.
“Inertia for air that MOVES relative to the surface results in the Coriolis effect.”
Yes, and this ‘effect’ is generated by the atmospheric behaviour ‘above’ the surface!
Best regards, Ray.
RC: “The height of troposphere and hence the column mass is two times more at the equator than the poles.”
… hence the column mass is two times more at the equator than the poles?? No Roger, but at least you got it halfway right.
The columnar mass is not double at the equator or the surface pressure would be double there also. You are forgetting to consider what the density is at the two extremes, which by itself proves why you are off by about 100% for the comparative columnar masses that you speak of, they are nearly identical. Do the math.
Have you ever considered opening a good atmospheric physics book, or better, maybe reading of why density is so important for pilots and how they do calculate the necessary densities at various altitudes in these two extreme examples which shows why the surface pressure is directly dependent on the columnar mass above the surface? Think of the integrated densities from the surface upward to correct your thinking on this topic.
wayne says: April 3, 2016 at 7:45 am
“or better, maybe reading of why density is so important for pilots and how they do calculate the necessary densities at various altitudes in these two extreme examples which shows why the surface pressure is directly dependent on the columnar mass above the surface?”
This may not be a good example wayne. The ‘principle mandate’ is for ‘take off’ safety/surety IMHO.
The aerodynamic of an aerofoil relies on ‘inertia’ to the top side of the wing. Density is an ‘issue’, but only for the ‘cord’ of the wing. The ‘angle of attack’ can enable ‘take off’ for an aircraft with the same aerofoil, or ‘cord’ section of wing, that couldn’t do so without an/the ‘angle of attack’ that produces the undesired effect of ‘drag’.
However, this is a pertinent point.
Best regards, Ray.
wayne says:
April 3, 2016 at 7:45 am
The columnar mass is not double at the equator or the surface pressure would be double there also.
I agree that the area under the density /height graph at poles and equator is a way to compare the mass of a column at each place.
Please let me see your calculation of the relative mass of a column of air at the poles and at the equator.
Roger Clague says: March 31, 2016 at 5:15 pm
“The difference in column mass at the equator and poles is x2 not 0.03%.”
Clueless nonsense.
suricat says: April 3, 2016 at 2:51 am
“Your description reads as an expansion of gas within a region of a ‘fixed enclosure’. Data (and datum’s [not to mention atractors]) are missing ”
http://www.esrl.noaa.gov/psd/map/clim/glbcir.anim.shtml
Try to understand why eg the 200 mb level or the 500 mb one is so much higher in the tropics than near the poles.
If you heat a gas it EXPANDS unless its volume is fixed.
“What is it that troubles you the most with atmospheric convection?”
The incredible amount of nonsense that is repeated over and over again on this blog about a simple subject as HE and convection.
“You’ve been a bit mean with your “0,3% lower at the equator than at the poles” figure. 32 ft/sec^2 (gravity constant) – ~3 in/sec^2 (gravity ‘counterpoise’) is a lot closer to 1% than your estimation.”
https://en.wikipedia.org/wiki/Gravity_of_Earth#Latitude
This one and other sources give the EFFECTIVE gravity at the equator as ~9,780 m/s^2 and near the poles ~9,832 m/s^2.
Difference 9,832-9,780= 0,052 m/s^2 which is ~0,51 % of 9,832 m/s^2.
Of this 0,51% ~0,3% is caused by the centrifugal (inertial) effect and the remaining 0,21% by the equatorial bulge. For atmospheric consideration these two effects are totally irrelevant against the much larger effect of gravity itself.
“Both Earth’s centrifuge and H2O’s diffusion influence lead to the establishment of a/the ‘Hadley cell/s’.”
Complete and utter nonsense.
Ben Wouters says:
April 4, 2016 at 1:01 pm
Do you have a calculation of relative mass of a troposphere air column at equator and poles?
Ben Wouters says:
April 4, 2016 at 1:21 pm
Try to understand why eg the 200 mb level or the 500 mb one is so much higher in the tropics than near the poles.
If you heat a gas it EXPANDS unless its volume is fixed.
RogerC: Troposphere height at equator is x2 height at poles
It seems you are saying the troposphere is higher in the tropics than the poles because of heat and the gas law. As here:
http://www.met.tamu.edu/class/atmo203/tut/pres/answer62.html#d
He also uses heat and gas law and gets only 0.1 x difference in air column height between equator and poles (30K difference).
Ben Wouters says: April 4, 2016 at 1:21 pm
“Try to understand why eg the 200 mb level or the 500 mb one is so much higher in the tropics than near the poles.
If you heat a gas it EXPANDS unless its volume is fixed.”
I’m not ‘thick’ Ben! Please try to understand that you don’t need to “heat a gas” to make/force its ‘apparent expansion’! Just ‘add’ water vapour to Earth’s atmosphere and see what happens (it becomes ‘less dense’, thus, ‘expanded’).
IMHO you may take benefit from a ‘~basic course’ for Chemistry (the non-bio discipline).
“suricat says: April 3, 2016 at 2:51 am
Ben Wouters says: April 4, 2016 at 1:21 pm
“What is it that troubles you the most with atmospheric convection?”
The incredible amount of nonsense that is repeated over and over again on this blog about a simple subject as HE and convection.”
This thread isn’t about “HE” AFAIK. Its about the meaning behind the convecting circulations that an atmosphere may exhibit. Thus, ‘HE’ is a ‘part’ of this discussion, but the discussion field is wider than this singular subject. I’ll help where I’m able to do so.
“suricat says: April 3, 2016 at 2:51 am
Ben Wouters says: April 4, 2016 at 1:21 pm
“You’ve been a bit mean with your “0,3% lower at the equator than at the poles” figure. 32 ft/sec^2 (gravity constant) – ~3 in/sec^2 (gravity ‘counterpoise’) is a lot closer to 1% than your estimation.”
https://en.wikipedia.org/wiki/Gravity_of_Earth#Latitude
This one and other sources give the EFFECTIVE gravity at the equator as ~9,780 m/s^2 and near the poles ~9,832 m/s^2.
Difference 9,832-9,780= 0,052 m/s^2 which is ~0,51 % of 9,832 m/s^2.
Of this 0,51% ~0,3% is caused by the centrifugal (inertial) effect and the remaining 0,21% by the equatorial bulge. For atmospheric consideration these two effects are totally irrelevant against the much larger effect of gravity itself.”
Ben. Beware of ‘unfinished web pages’ on Wikipedia! If ‘other sites’ concur with the ‘status quo’ for the/a ‘consensus’ there may well be ‘new science’ being disclosed as we speak, or ‘old science’ being ‘re-invented’.
I’ve too many criticisms to write here, but consider myself a ‘critic’ to your ‘current’ dialogue.
“Complete and utter nonsense.”
Your loss Ben! You need to encompass an understanding of ‘convection’ without the ‘need’ for a ‘change of temperature’.
Whilst I would invoke a ‘label’ of ‘convection/advection’, many here would ‘label’ this as ‘convection’.
I’m at a disadvantage here. Please disclose your understanding of the differentiation between ‘convection’ and ‘advection’.
Best regards, Ray.
suricat says: April 5, 2016 at 1:26 am
“I’m not ‘thick’ Ben! Please try to understand that you don’t need to “heat a gas” to make/force its ‘apparent expansion’!”
I need to expand this argument.
Your link made no connection, or refference, to a ‘tidal influence’. Both Solar and Lunar gravity influence ‘negates/alters’ the influence of an ‘Earth centric’ gravity field per se. ‘Tidal forcings’ need to be addressed!
Best regards, Ray.
suricat says: April 5, 2016 at 1:26 am
“IMHO you may take benefit from a ‘~basic course’ for Chemistry (the non-bio discipline).”
To be able to come up with the same nonsense Roger Clague is promoting here?
No thanks.
“You need to encompass an understanding of ‘convection’ without the ‘need’ for a ‘change of temperature’.”
Are we still discussing earths atmosphere???
“Please disclose your understanding of the differentiation between ‘convection’ and ‘advection’.”
I lost count of how many times I explained this.
Again:
http://glossary.ametsoc.org/wiki/Advection
Convection is the vertical movement of air due to buoyancy (disturbance in the HE).
suricat says: April 7, 2016 at 2:15 am
“Your link made no connection, or refference, to a ‘tidal influence’. Both Solar and Lunar gravity influence ‘negates/alters’ the influence of an ‘Earth centric’ gravity field per se. ‘Tidal forcings’ need to be addressed!”
Yet another negligible effect.
Back in june 2015! I posted:
with this pdf http://www.space-electronics.com/Literature/Precise_Measurement_of_Mass.PDF
which you didn’t bother to read.
On page 8 Tidal variations are discussed.
Ben Wouters says: April 7, 2016 at 2:44 pm
“suricat says: April 5, 2016 at 1:26 am
“IMHO you may take benefit from a ‘~basic course’ for Chemistry (the non-bio discipline).”
To be able to come up with the same nonsense Roger Clague is promoting here?
No thanks.”
RC is also into ‘quantum mechanics’. I wouldn’t put this in the class of “nonsense” Ben.
““You need to encompass an understanding of ‘convection’ without the ‘need’ for a ‘change of temperature’.”
Are we still discussing earths atmosphere???”
Yes we are, but many other planets exhibit the ‘phase change’ behaviour that exhibits on Earth (with ‘other’ compounds).
““Please disclose your understanding of the differentiation between ‘convection’ and ‘advection’.”
I lost count of how many times I explained this.
Again:
http://glossary.ametsoc.org/wiki/Advection”
You can’t hope to establish an understanding of ‘global circulation’ from ‘surface observation’ alone. On reading your link, “where u, v, and w are the wind components in the eastward, northward, and vertically upward directions, respectively. The first two terms compose the horizontal advection and the last term is the vertical advection.”, leads me to believe that the ‘overspill’ from equatorial latitudes is/becomes a ‘positive’ quality for “u”.
The ‘description’ seems ‘odd’. At ~equatorial latitudes this is always a, as described, ‘negative’ quality (surface forcing ‘wind’, thus, atmospheric boundary layer lagging surface speed [east to west wind at ‘~the surface’]).
“Convection is the vertical movement of air due to buoyancy (disturbance in the HE).”
Yes, whilst I would concur, ‘HE’ is almost never met in the field of observation.
I’ve no time to answer your next posting just now, I’ll do this when time permits.
Best regards, Ray.
Ben Wouters says:
April 7, 2016 at 2:44 pm
http://glossary.ametsoc.org/wiki/Advection
1. Horizontal motion is large-scale and vertical motion is local.
2. Motion in the atmosphere is like in a liquid
3. Motion in the atmosphere is similar in all directions and called advection
I disagree with each of these claims.
Convection is not local and not like in a liquid
Convection is world-wide and mainly due to molecular diffusion not mass motion. Molecular diffusion is a chemical concept and known act vertically in the atmosphere.
.
You say: Convection is the vertical movement of air due to buoyancy (disturbance in the HE).
How does a disturbance in HE cause buoyancy?
Buoyancy is world-wide and not a disturbance. Buoyancy is caused by the permanent large and stable vertical p/h gradient. Horizontal winds are caused varying and small horizontal pressure differences
Convection is not wind.
You seem accept this by referring to HE. You say air pressure is caused by weight of air. You don’t say wind is caused by weight of air.
suricat says: April 9, 2016 at 2:56 am
“RC is also into ‘quantum mechanics’.”
Obviously doesn’t come with an understanding of atmospheres.
“You can’t hope to establish an understanding of ‘global circulation’ from ‘surface observation’ alone.”
Let’s stick to HE and simple convection, the subject of this thread.
Seems complicated enough to understand.
“Yes, whilst I would concur, ‘HE’ is almost never met in the field of observation.”
Where on planet earth do you see denser air above less dense air continuously??????
Roger Clague says: April 9, 2016 at 3:38 pm
“Convection is world-wide and mainly due to molecular diffusion not mass motion.”
Must be the reason why gliders have to circle often steeply to stay in the rising air and not enter the surrounding sinking air.
“How does a disturbance in HE cause buoyancy?”
Air that is less dense than surrounding air will rise, while denser air will sink, until HE is re-established.
“Convection is not wind.”
Wow. And a car is not a bicycle, a dog not a cat…..
Amazing observations.
Ben Wouters says: April 10, 2016 at 8:41 pm
“suricat says: April 9, 2016 at 2:56 am
“RC is also into ‘quantum mechanics’.”
Obviously doesn’t come with an understanding of atmospheres.”
No, it comes with an understanding of what constitutes an atmosphere.
“”suricat says: April 9, 2016 at 2:56 am”
“You can’t hope to establish an understanding of ‘global circulation’ from ‘surface observation’ alone.”
Let’s stick to HE and simple convection, the subject of this thread.
Seems complicated enough to understand.”
Now you’re taking the piss. ‘HE’ is a ‘superimposed construct’ for a ‘stable atmosphere’. It doesn’t exist, but is ‘presumed’ for the sake of a valid observation for an ‘anomalous convective’ event.
The problem with this is that ‘other advective’ components aren’t recognised in/within the scenario.
“”suricat says: April 9, 2016 at 2:56 am”
“Yes, whilst I would concur, ‘HE’ is almost never met in the field of observation.”
Where on planet earth do you see denser air above less dense air continuously??????”
Anywhere outside of a convective cell.
I’d like to address the main reason for my post/response Ben.
“Ben Wouters says: April 7, 2016 at 2:59 pm”
“Your link made no connection, or reference, to a ‘tidal influence’. Both Solar and Lunar gravity influence ‘negates/alters’ the influence of an ‘Earth centric’ gravity field per se. ‘Tidal forcings’ need to be addressed!”
Yet another negligible effect.””
So the high and low tide levels that are observed are of “negligible effect”???
“Back in June 2015! I posted:
with this pdf http://www.space-electronics.com/Literature/Precise_Measurement_of_Mass.PDF
which you didn’t bother to read.
On page 8 Tidal variations are discussed.”
Your comment here is unobtainable, but the paper is extant. I’ll read it when I can.
Ben. The ‘three body scenario’ is evident for the Earth Sol Lunar system for the energetic center of/for gravity for each proponent. Take care!
Best regards, Ray.
suricat says: April 11, 2016 at 2:57 am
“”suricat says: April 9, 2016 at 2:56 am”
“Yes, whilst I would concur, ‘HE’ is almost never met in the field of observation.”
(BW) Where on planet earth do you see denser air above less dense air continuously??????”
Anywhere outside of a convective cell.”
Increasing density with altitude?????????????????
A convective cell LESS DENSE air that rises to re-establish HE.
Exactly the other way around to what you claim !!!!!!!!!!!!
“So the high and low tide levels that are observed are of “negligible effect”???”
Where discussing our ATMOSPHERE, not the oceans.
see https://en.wikipedia.org/wiki/Atmospheric_tide
especially https://en.wikipedia.org/wiki/Atmospheric_tide#Lunar_atmospheric_tides
Roger C: Convection is not wind
BenW: Amazing observations.
But here they say convection is wind.
http://glossary.ametsoc.org/wiki/Advection
“Regarding the general distinction (in meteorology) between advection and convection, the former describes the predominantly horizontal, large-scale motions of the atmosphere, while convection describes the predominantly vertical, locally induced motions.”
The only difference mentioned is scale, large-scale or locally induced. Also in the equation all directions are the same. So they say convection is a form of advection, a form of mass motion that is wind. There is no mention of diffusion.
There are small-scale winds that go up, called Fohn winds. There is also vertical motion of air by diffusion. Diffusion is caused by molecular motion, not mass motion.
Is all convection a form of advection?
Is convection only caused by mass motion of air?
Roger Clague says: April 12, 2016 at 2:46 pm
“But here they say convection is wind.
http://glossary.ametsoc.org/wiki/Advection”
Where??
“The only difference mentioned is scale, large-scale or locally induced. ”
Perhaps in quantum mechanics HORIZONTAL and VERTICAL are the same, but not so in meteorology.
“There is no mention of diffusion.”
And why should there be one??
“There are small-scale winds that go up, called Fohn winds.”
Not even close.
see https://en.wikipedia.org/wiki/Foehn_wind
“Is all convection a form of advection?”
Yes.
“Is convection only caused by mass motion of air?”
Convection IS (vertical) mass motion of air caused by density differences..
Ben Wouters says: April 11, 2016 at 10:30 am
“Increasing density with altitude?????????????????
A convective cell LESS DENSE air that rises to re-establish HE.
Exactly the other way around to what you claim !!!!!!!!!!!!”
Your response to the answer that I gave for the question that you asked has ‘no relationship’ to this comment! Why did you make it?
‘Atmospheric convection’ is a ‘continual process’, ‘less dense’ air at a ‘low altitude’ is always ‘replacing’ ‘more dense’ air at a ‘high altitude’.
I reiterate my response to your query “Where on planet earth do you see denser air above less dense air continuously??????” as “Anywhere outside of a convective cell.”.
Please think on this, or have your logic cells ‘advected elsewhere’?
““So the high and low tide levels that are observed are of “negligible effect”???”
Where discussing our ATMOSPHERE, not the oceans.”
Our host thinks that the two are difficult to differentiate between, and with good reason. Its easy to observe and recognise ‘tidal influence’ at the atmosphere/ocean interface, but its difficult to observe a ‘tidal influence’ within the atmosphere per se. Too much ‘static’ from ‘day/night temperature change’ influence, Sol’s ‘wind’ and the lack of a ‘convenient observable marker’ in the atmosphere (as your links show).
Perhaps we should consider that ‘tidal influence’ is equally as proportional for ‘the atmosphere’ as it is for the ‘atmosphere/ocean’ interface. ‘The two’ are subjected to the ‘same gravitational forcing’, but some ‘correctional factor’ may need to be applied to validate this.
Best regards, Ray.
Roger Clague says: April 12, 2016 at 2:46 pm
RC. IMHO ‘advection’ describes a ‘forced’ movement of mass (an ‘entrainment’), but ‘convection’ describes the ‘natural’ movement of mass that’s ‘forced’ by its own ‘state/structure/density’ where no other ‘mass influence forcing’ is involved.
This definition doesn’t bode well for ‘diffusion’ as a source of convection. When WV ‘percolates’ through the atmosphere to a higher altitude it also ‘detrained’ the atmosphere to follow its course to a ‘higher altitude’. This is ‘advection’.
With regard to your link, I think its bull. I’ll deffer to your latter remarks.
“Is all convection a form of advection?”
No! Convection is initialised only by the state of the mass per se.
“Is convection only caused by mass motion of air?”
No! ‘Advection’ is also a ‘causal effect’ for the “mass motion of air”. The “mass motion of air” is ‘asymptotic’, not ‘causal’ RC.
Best regards, Ray.
Roger Clague says: April 12, 2016 at 2:46 pm
“Roger C: Convection is not wind
BenW: Amazing observations.
But here they say convection is wind.
http://glossary.ametsoc.org/wiki/Advection
“Regarding the general distinction (in meteorology) between advection and convection, the former describes the predominantly horizontal, large-scale motions of the atmosphere, while convection describes the predominantly vertical, locally induced motions.”
The only difference mentioned is scale, large-scale or locally induced. Also in the equation all directions are the same. So they say convection is a form of advection, a form of mass motion that is wind. There is no mention of diffusion.”
I support your query RC. Not so much for the unmentioned diffusion that has an inertia value, but for the changing configuration between gravity and Earth’s centrifuge with latitudinal change (the ‘Coriolis’ effect). The big question is ‘how did we get there’!
I know this thread is long, but there is so much more to discuss here (diffusion should have its say/place here).
Best regards, Ray.
Ben Wouters says:
April 12, 2016 at 8:51 pm
Roger Clague says: April 12, 2016 at 2:46 pm
“But here they say convection is wind.
http://glossary.ametsoc.org/wiki/Advection”
BenW: Where??
RogerC: “The only difference mentioned is scale, large-scale or locally induced. ”
BenW: Perhaps in quantum mechanics HORIZONTAL and VERTICAL are the same, but not so in meteorology.
RogerC: Quantum mechanics is for matter at the atomic scale. The Schrodinger Equation has only the x direction. That is all directions are equivalent. That is no horizontal and vertical.
Ametsoc have two definitions.
Regarding the general distinction (in meteorology) between advection and convection, the former describes the predominantly horizontal, large-scale motions of the atmosphere, while convection describes the predominantly vertical, locally induced motions.
One for synoptic metrology and one for Meteorology
The difference seems to be synoptic metrology is the practice of weather forecasting and Meteorology is the theory that it used
The practice of metrology, weather forecasting, is to consider only horizontal movement as advection. Vertical movement, convection is considered differently.
The Theoretical metrology definition does not distinguish between horizontal and vertical movement. In the equation x,y and z are equivalent.
In science definitions in theory and those used practice must be the same.
Roger Clague says: April 16, 2016 at 6:36 pm
“The practice of metrology, weather forecasting, is to consider only horizontal movement as advection. Vertical movement, convection is considered differently.
The Theoretical metrology definition does not distinguish between horizontal and vertical movement. In the equation x,y and z are equivalent.
In science definitions in theory and those used practice must be the same.”
Fine. Now explain to the atmosphere that from now on wind is only allowed to flow strictly horizontal, and thermals, rain showers etc. (CONVECTION) are only allowed to rise strictly vertical.
Ben Wouters says: April 17, 2016 at 1:17 pm
“Fine. Now explain to the atmosphere that from now on wind is only allowed to flow strictly horizontal, and thermals, rain showers etc. (CONVECTION) are only allowed to rise strictly vertical.”
That isn’t necessary Ben, the atmosphere does what it does and we need to observe it accurately.
“(CONVECTION)” is always ‘mediated’ by ‘gravity’ and a ‘density differential’ who’s ‘x,y,z, orientation’ has its ‘z’ axis as ‘perpendicular’ to the local surface (the ‘z’ axis may be modified by the local topography)!
Advection, or ‘wind’, is generated by forces ‘other than “(CONVECTION)”‘ (when we ignore the surface wind induced by a local convection cell)! Let’s take a look at a ‘Polar cell’, as this is easier to comprehend.
Question. Why do you always end up ‘nearer’ the ‘pole’ when you move/walk ‘into the wind’ at either ‘polar’ near latitude?
RSPV.
Best regards, Ray.
Roger Clague says: April 16, 2016 at 6:36 pm
“In science definitions in theory and those used practice must be the same.”
I concur RC. However, these “definitions” seem to ‘diverge’ more than ‘come together’.
How to ‘interpolate’ this is difficult. Any suggestion?
Best regards, Ray.
suricat says:
April 18, 2016 at 2:32 am
“(CONVECTION)” is always ‘mediated’ by ‘gravity’ and a ‘density differential’ who’s ‘x,y,z, orientation’ has its ‘z’ axis as ‘perpendicular’ to the local surface (the ‘z’ axis may be modified by the local topography)!
and
Advection, or ‘wind’, is generated by forces ‘other than “(CONVECTION)”
I agree and add:
Thermals are caused by heat. Rain is caused by gravity and condensation.
Wind is an equalizing of pressure and is not caused by heat, gravity or condensation.
It is not helpful to consider wind, thermals and rain together as mass movement by advection as ametsoc does.
The horizontal and vertical directions in the atmosphere have different physics.
suricat says:
April 18, 2016 at 3:08 am
However, these “definitions” seem to ‘diverge’ more than ‘come together’.
There are 2 definitions in
http://glossary.ametsoc.org/wiki/Advection
The result is meteorologists know convection is not wind but theorists claim they are the same.
and diffusion is not relevant.
Another view of diffusion and advection in the atmosphere:
Click to access paper.pdf
The Gaussian plume model is a standard approach for studying the transport of airborne contaminants due to turbulent diffusionand advection by the wind.
See especially fig. 1.
suricat says: April 18, 2016 at 2:32 am
“Question. Why do you always end up ‘nearer’ the ‘pole’ when you move/walk ‘into the wind’ at either ‘polar’ near latitude?”
You don’t. Only when a high pressure area happens to be present exactly over the pole your statement is true. Which way the wind blows has been known since 1857.
http://www.britannica.com/science/Buys-Ballots-Law
Roger Clague says: April 18, 2016 at 11:32 am
In the main I concur RC.
Best regards, Ray.
Roger Clague says: April 18, 2016 at 2:48 pm
“There are 2 definitions in”
Aye, and Ben can’t get to grips with this.
“Another view of diffusion and advection in the atmosphere:
http://people.math.sfu.ca/~stockie/atmos/paper.pdf”
Disagree! This paper seems to be about ‘fallout’ from the atmosphere.
Best regards, Ray.
Ben Wouters says: April 18, 2016 at 8:05 pm
“You don’t. Only when a high pressure area happens to be present exactly over the pole your statement is true.”
I’ll savour this response later. Good night all.
Best regards, Ray.
suricat says: April 19, 2016 at 3:20 am
“Roger Clague says: April 18, 2016 at 2:48 pm
“There are 2 definitions in”
Aye, and Ben can’t get to grips with this.”
definition:
“The process of transport of an atmospheric property solely by the mass motion (velocity field) of the atmosphere; also, the rate of change of the value of the advected property at a given point.”
And the second definition would be ??
suricat says: April 19, 2016 at 3:33 am
“I’ll savour this response later. Good night all.”
Apologies Ben! This wasn’t intended to be a ‘trite’ remark, it was late, I was knackered and its late again now (for me).
I’ll get back when I can. 🙂
Best regards, Ray.
BenW quotes from
http://glossary.ametsoc.org/wiki/Advection
The process of transport of an atmospheric property solely by the mass motion (velocity field) of the atmosphere
as a definition.
This is not a definition it is an assumption. The assumption that all transport in the atmosphere, including vertically, is by mass motion.
Diffusion, molecular motion, is also mass motion but is specifically excluded from fluid mechanics, the theory of meteorology.
http://glossary.ametsoc.org/wiki/Wind_vector
The two- or three-dimensional vector describing the instantaneous wind magnitude and direction at a point.
Advection is a wind vector.
2-D is horizontal used in weather forecasting
3-D is horizontal + vertical as in the theory of fluid dynamics.
Advection has 2 meanings in this American Meteorology Society glossary
Roger Clague says: April 21, 2016 at 3:21 pm
“This is not a definition it is an assumption. The assumption that all transport in the atmosphere, including vertically, is by mass motion.”
????????????????
“Diffusion, molecular motion, is also mass motion but is specifically excluded from fluid mechanics, the theory of meteorology.”
And with good reason:
http://glossary.ametsoc.org/wiki/Diffusion
“The transport of matter solely by the random motions of individual molecules not moving together in coherent groups.”
Notice “not moving together in coherent groups” !!
So let’s call advection advection, convection convection, diffusion diffusion, conduction conduction, radiation radiation etc.etc.
suricat says: April 20, 2016 at 2:32 am
“I’ll get back when I can.:) ”
Its again ‘late’ for me, but here goes.
“suricat says: April 18, 2016 at 2:32 am
“Question. Why do you always end up ‘nearer’ the ‘pole’ when you move/walk ‘into the wind’ at either ‘polar’ near latitude?”
You don’t. Only when a high pressure area happens to be present exactly over the pole your statement is true. Which way the wind blows has been known since 1857.
http://www.britannica.com/science/Buys-Ballots-Law”
Think again. Your ‘link’ relates to ‘how to determine the direction to the center of a vortex’ and proposes a ‘reverse logic’ to my affirmation. Again, walk ‘into the wind’ near a pole and you’ll get ~to the pole (I could expand on how/why the N/H pole vortex splits, but don’t want to add to complexity here).
Ben Wouters says: April 19, 2016 at 2:21 pm
“suricat says: April 19, 2016 at 3:20 am
“Roger Clague says: April 18, 2016 at 2:48 pm
“There are 2 definitions in”
Aye, and Ben can’t get to grips with this.”
definition:
“The process of transport of an atmospheric property solely by the mass motion (velocity field) of the atmosphere; also, the rate of change of the value of the advected property at a given point.”
And the second definition would be ??”
The ‘convective property’ of a ‘lighter than air’ gas at Earth’s surface.
WV production at Earth’s surface is constant! Notwithstanding that the WV molecule ‘permeates’ (diffuses) to a greater depth than most other atmospheric molecules its ‘behaviour’ is considered to be one of a ‘diffusive’ property (probably wrong).
The ‘lighter than air’ property of WV establishes WV as a ‘convective’ proponent, but its continual production at Earth’s surface places it in the category of an ‘advective agent’!
Which is it in ‘weather speak’?
Ben Wouters says: April 23, 2016 at 11:15 am
““Diffusion, molecular motion, is also mass motion but is specifically excluded from fluid mechanics, the theory of meteorology.”
And with good reason:
http://glossary.ametsoc.org/wiki/Diffusion
“The transport of matter solely by the random motions of individual molecules not moving together in coherent groups.”
Notice “not moving together in coherent groups” !!
So let’s call advection advection, convection convection, diffusion diffusion, conduction conduction, radiation radiation etc.etc.”
So what do we call a ‘hybrid’ for ‘convection and advection’???
Best regards, Ray.
Roger Clague says: April 21, 2016 at 3:21 pm
Hi Roger. I particularly noticed the statement of ‘atmospheric property’ in your quoted link (this phrase didn’t posses a hyperlink on the page), so I made an ‘on site’ search for it. You may want to do the same because it seems to relate to differing atmospheric ‘states'(?) and doesn’t make full sense to me.
“as a definition.
This is not a definition it is an assumption. The assumption that all transport in the atmosphere, including vertically, is by mass motion.”
I’d like a better definition for ‘transport’ per se. Is this the ‘transport’ for/of ‘energy’, ‘mass’, or ‘radiation’? I realise that ‘radiation’ per se has little place for consideration in a thread on the subject of ‘convection’, but it would be nice to ‘exclude’ the possibility of its consideration.
“Diffusion, molecular motion, is also mass motion but is specifically excluded from fluid mechanics, the theory of meteorology.”
Disagree. ‘Fluid mechanics’ includes ‘mixing ratios’ that depend on the ‘diffusion property’ of the gasses observed. However, this is not to be considered as a ‘mass movement’, but solely relates to the ‘mixing property’ for a particular ‘species’ within a ‘gaseous environment’ of variant species.
As for “the theory of meteorology”. Isn’t this about ‘bar graphs’ and ‘pressure change’?
“Advection is a wind vector.
2-D is horizontal used in weather forecasting
3-D is horizontal + vertical as in the theory of fluid dynamics.
Advection has 2 meanings in this American Meteorology Society glossary”
Now I’m totally confused! 🙂
Best regards, Ray.
Ben Wouters says:
April 23, 2016 at 11:15 am
http://glossary.ametsoc.org/wiki/Diffusion
“The transport of matter solely by the random motions of individual molecules not moving together in coherent groups.”
Notice “not moving together in coherent groups” !
By coherent groups I assume you mean groups of molecules that keep the same relative positions.
In diffusion the molecules of different mass and therefore velocity change their relative positions,
Transport of matter vertically is not only by coherent groups, that is advection. Water vapor (H2O) rises relative to air by moving faster than air (N2 and O2), moving between air molecules not with them.
The important role of diffusion in convection is ignored by meteorology
Ben W says: ‘Convection IS (vertical) mass motion of air caused by density differences.’
What relationship do you see between weight and density, if any?
If a ‘parcel’ of warming air expands it becomes less dense, but the parcel still weighs the same – unless it sheds some of its mass somehow.
suricat says: April 24, 2016 at 2:46 am
“Think again. ”
No need to. The buys Ballot LAW has been proven over and over again.
It is called a LAW for a reason.
If a low pressure area sits directly over the North pole, the surface wind will spiral TOWARDS the pole. https://en.wikipedia.org/wiki/Polar_vortex
If you walk into the wind, you will spiral AWAY from the pole.
“The ‘convective property’ of a ‘lighter than air’ gas at Earth’s surface.”
Nonsense.
We’ve been through this before.
Read up at the end of the comments to this post:
WV is well mixed and moves with the other gasses. This is high school physics:
http://www.recreationalflying.com/tutorials/meteorology/section1a.html#atmospheric_moisture
“So what do we call a ‘hybrid’ for ‘convection and advection’???”
Which hybrid ???
suricat says: April 25, 2016 at 2:14 am
“I’d like a better definition for ‘transport’ per se. Is this the ‘transport’ for/of ‘energy’, ‘mass’, or ‘radiation’?”
Not sure if you have access to television in your part of the world, but on the daily weather talk the meteorologist often shows warm fronts, cold fronts, occlusions etc.etc.
They are all at the front of moving air masses…………………
Roger Clague says: April 26, 2016 at 7:25 am
“By coherent groups I assume you mean groups of molecules that keep the same relative positions.”
If you believe that molecules in a moving air mass stretching 10s or even hundreds of kilometers will maintain their relative positions, you’re even more clueless than I already gathered.
oldbrew says: April 27, 2016 at 4:35 pm
“What relationship do you see between weight and density, if any?”
Density is mass per unit volume. Increase the volume for a given mass, and the density will drop.
Assuming constant gravity the weight of that mass of air will also drop. (specific weight).
So in a nutshell we should believe that when a given volume of air expands, it loses weight without losing any mass?
oldbrew says: April 27, 2016 at 7:45 pm
“So in a nutshell we should believe that when a given volume of air expands, it loses weight without losing any mass?”
No, it looses SPECIFIC weight, weight per unit volume. https://en.wikipedia.org/wiki/Specific_weight
When expansion occurs there is then less mass and less weight within the original volume.
As a consequence, the upward pressure gradient force can lift that reduced mass within the original volume to a greater height than that of the more compact / denser surrounding gases.
The upward pressure gradient force is derived from the ‘excess’ kinetic energy at the surface over and above that which is lost from surface to space via radiation.
That ‘excess’ kinetic energy is that which needs to remain permanently present at the surface to maintain constant convective overturning so that atmospheric height can be stable in accordance with hydrostatic equilibrium.
That kinetic energy is constantly being recycled from KE to PE and back again within convective uplift and descent and therefore cannot be radiated to space.
Stephen Wilde says:
April 27, 2016 at 8:11 pm
The upward pressure gradient force is derived from the ‘excess’ kinetic energy at the surface over and above that which is lost from surface to space via radiation.
The pressure gradient force is derived from kinetic energy
Kinetic energy of air molecules is equal in all directions.
Why is the pressure gradient force upwards?
Ben Wouters says:
April 27, 2016 at 8:10 pm
No, it[air] looses SPECIFIC weight, weight per unit volume. https://en.wikipedia.org/wiki/Specific_weight
At this well-known site
http://www.engineeringtoolbox.com/density-specific-weight-gravity-d_290.html
There is no specific weight of air, or any other gas listed. This is because the weight of a gas cannot be measured. Weight of gas is only ever calculated using an wrongly assumed equation.
Specific gravity of air, N2 and O2 is listed. This is because specific gravity is relative density. Density is a function of mass not weight.
Gas has mass not weight.
‘Here’s an odd-seeming question. Does air weigh anything?’ [demo with 2 balloons]
http://indianapublicmedia.org/amomentofscience/heavy-air/
If air is at a point where it is in hydrostatic equilibrium then it has no apparent weight but nonetheless it still has weight which is being offset by the upward pressure gradient force.
If it is not at a point of hydrostatic equilibrium then it will either have positive weight (falling) or negative weight (rising) depending on its relationship with the upward pressure gradient force.
WHAT IS THE PRESSURE GRADIENT FORCE?
‘The pressure gradient force is the force produced when air with different pressures are placed next to each other.’
http://www.theweatherprediction.com/habyhints2/475/
There seems to be a word missing after ‘air’, because ‘air…are’ is not correct English.
Roger Clague says: April 26, 2016 at 7:25 am
“Ben Wouters says:
April 23, 2016 at 11:15 am
http://glossary.ametsoc.org/wiki/Diffusion
“The transport of matter solely by the random motions of individual molecules not moving together in coherent groups.”
Notice “not moving together in coherent groups” !
By coherent groups I assume you mean groups of molecules that keep the same relative positions.”
My assumption was the same RC. However, this observation fails any ‘test’ for a ‘parcel’ analysis of ‘atmospheric behaviour’.
“In diffusion the molecules of different mass and therefore velocity change their relative positions,”
NB. This quote should have ended with a ‘period’ (with ‘other/another’ syntax correction) IMHO!
However, the ‘inertia’ value of a molecule is defined by its ‘mass’ value WR to its velocity. The ‘total kinetic’ of a molecule within the environment of a ‘mixed gas’ is ~equal for each molecule (Avogadro constant: https://en.wikipedia.org/wiki/Avogadro_constant ).
Thus, molecules with a lesser mass travel at a greater velocity than those molecules with a greater mass to maintain the regional ‘electrostatic compression’ average!
“Transport of matter vertically is not only by coherent groups, that is advection. Water vapor (H2O) rises relative to air by moving faster than air (N2 and O2), moving between air molecules not with them.”
I concur with reservation RC.
“The important role of diffusion in convection is ignored by meteorology”
I concur without reservation RC!
Best regards, Ray.
Roger Clague says: April 28, 2016 at 2:53 pm
“Why is the pressure gradient force upwards?”
The VERTICAL pressure gradient force is upwards because it opposes gravity, which is downwards. (=> Hydrostatic Equilibrium……)
The HORIZONTAL pressure gradient force is horizontal…..
Causes movement of air masses.
Roger Clague says: April 28, 2016 at 3:05 pm
“At this well-known site
http://www.engineeringtoolbox.com/density-specific-weight-gravity-d_290.html
There is no specific weight of air, or any other gas listed. This is because the weight of a gas cannot be measured. Weight of gas is only ever calculated using an wrongly assumed equation.”
At this well-known site
https://en.wikipedia.org/wiki/Specific_weight#Specific_weight_of_air
the specific weight is given for a range of temperatures.
Comes from Finnemore, J. E. (2002). Fluid Mechanics with Engineering Applications. New York: McGraw-Hill. ISBN 0-07-243202-0.
At that other well-known site they probably assume that their visitors are able to multiply density with gravity to calculate specific weight.
oldbrew says: April 28, 2016 at 8:36 pm
“‘Here’s an odd-seeming question. Does air weigh anything?’ [demo with 2 balloons]
http://indianapublicmedia.org/amomentofscience/heavy-air/”
Doesn’t take the effect of buoyancy for the blown up balloon into consideration.
Use two identical steel diving cylinders (fixed volume) and the effect is obvious to any non-engineer.
suricat says: April 29, 2016 at 3:24 am
““The important role of diffusion in convection is ignored by meteorology”
I concur without reservation RC!”
And that important role in convection is ??
Ben Wouters says: April 29, 2016 at 4:21 pm
(I’ve skipped postings to respond to your query Ben)
“suricat says: April 29, 2016 at 3:24 am
““The important role of diffusion in convection is ignored by meteorology”
I concur without reservation RC!”
And that important role in convection is ??”
ADVECTION Ben!
‘WV’ (water vapour) is a ‘lighter than air’ gas that possesses less mass per molecule than most other atmospheric constituents. Its effect is threefold.
1. It’s the first gas to penetrate to greatest depth by way of its greater velocity due to its low molecular mass within the atmospheric gas mix.
2. Its low molecular mass provides ‘buoyancy’ WRT ‘other’ atmospheric components.
3. Its continual production at the ‘surface’ provides a means of ‘advection’ towards ‘greater altitudes’.
What are your thoughts on ‘detrainment’ Ben??
Best regards, Ray.
suricat says: April 30, 2016 at 2:25 am
“What are your thoughts on ‘detrainment’ Ben??”
No response yet.
To ‘detrain’ you first need to ‘en-train’ Ben. The term relates to a ‘piggy back’ scenario/simile for a situation/configuration where a subject is ‘moved’ by another subject. IOW ‘atractors meet’.
WV ‘detrains’ at the tropopause, but ‘entrains’ at all altitudes below this, resulting in ‘vertical to the surface advection’ of the atmosphere, which enhances convection at these altitudes.
Thus, ‘convection’ per se is obfuscated by the inclusion of WV (or a/any compound that exhibits ‘phase change’ in the ‘natural’ atmosphere of any other planet)!
Best regards, Ray.
suricat says: April 30, 2016 at 2:25 am
“And that important role in convection is ??”
ADVECTION Ben!”
I’m not going to repeat previous responses to this nonsense.
I provided a link: http://www.recreationalflying.com/tutorials/meteorology/section1a.html#atmospheric_moisture
The idea is that you read the linked article, agree or disagree and respond.
This is knowledge developed somewhere in the 19th century, and beyond dispute.
Perhaps time to catch up?
Suggest to study the whole tutorial on basic meteorology:
http://www.recreationalflying.com/tutorials/meteorology/index.html
Might prevent you from posting nonsense like this:
“WV ‘detrains’ at the tropopause, but ‘entrains’ at all altitudes below this, resulting in ‘vertical to the surface advection’ of the atmosphere, which enhances convection at these altitudes.”
Shows no clue about what convection actually is.
Do you have any idea what temperatures the air at the tropopause has?
And what the maximum WV part of the gas mix is at those temperatures?
(WV is the GAS water vapour, not droplets of water or ice particles!!!!)
Ben Wouters says: May 5, 2016 at 9:04 am
“I’m not going to repeat previous responses to this nonsense.”
You should Ben, and try to understand it!
“I provided a link: http://www.recreationalflying.com/tutorials/meteorology/section1a.html#atmospheric_moisture
The idea is that you read the linked article, agree or disagree and respond.
This is knowledge developed somewhere in the 19th century, and beyond dispute.
Perhaps time to catch up?”
I’ve already done that! Atmospheric science wasn’t as ‘cutting edge’ it is at present day. ‘Advection’ plays a significant part of what was understood to be convection ‘in the day’.
“Suggest to study the whole tutorial on basic meteorology:
http://www.recreationalflying.com/tutorials/meteorology/index.html”
Why?
“Might prevent you from posting nonsense like this:
“WV ‘detrains’ at the tropopause, but ‘entrains’ at all altitudes below this, resulting in ‘vertical to the surface advection’ of the atmosphere, which enhances convection at these altitudes.”
Shows no clue about what convection actually is.”
No. This shows that ‘convection’ per se is ‘duplicitous’ in its action.
“Do you have any idea what temperatures the air at the tropopause has?
And what the maximum WV part of the gas mix is at those temperatures?”
I do.
“(WV is the GAS water vapour, not droplets of water or ice particles!!!!)”
This is my point, however I’ll remind you that both ‘water’ and ‘ice’ ‘sublimate’ to the ‘WV’ (the ‘gaseous’ Water Vapour) of which I speak!
Do you understand this?
Best regards, Ray.
Ben Wouters says:
May 5, 2016 at 9:04 am
Suggest to study the whole tutorial on basic meteorology:
http://www.recreationalflying.com/tutorials/meteorology/index.html
In sections 1.3 and 1.4 there are two different explanations of buoyancy.
In 1.3 buoyancy is caused by an in-balance in the hydrostatic equilibrium. An in-balance between weight and the upward vertical component of the pressure gradient force ( whatever that is).
In 1.4. weight is not part of the explanation. That is apart from the incorrect term relative weight, w2hich should be called relative mass.
A moist atmosphere that includes water vapour is slightly less dense than a dry atmosphere at the same temperature and pressure; because the vapour displaces a corresponding amount of the other gases per unit volume and the molecular weight ratio of water vapour to dry air is 0.62:1*. Thus a parcel of moister air is slightly more buoyant than surrounding drier air.
I agree with this molecular explanation of buoyancy.
The water vapour molecules displace a corresponding amount of the other gases, N2 and O2 The corresponding amount is the number of molecules, not the mass of molecules. As a result the density becomes less and buoyancy is created by this molecular property of gas.
A parcels of air is a fluid dynamics concept that has no molecular properties. Meteorology theory is not consistent. Meteorology is not science. Meteorology as weather forecasting is a useful application of statistics.
The atmosphere can be studied by applying the theories of physics, chemistry and biology. Physics has the concept of energy, chemistry the concept of molecules and biology the concept of organisms. There is no unique and general concept in meteorology.
Roger Clague says: May 7, 2016 at 6:42 pm
“The water vapour molecules displace a corresponding amount of the other gases, N2 and O2 The corresponding amount is the number of molecules, not the mass of molecules. As a result the density becomes less and buoyancy is created by this molecular property of gas.”
I think you just ‘hit the nail on the head’ here Roger (I assume you intend that “The corresponding amount is the number of molecules, not the mass of molecules.” should read that ‘The corresponding amount for a volume is the number of molecules within that volume, not the mass of molecules for that same volume.). There are differences between ‘HE’ (Hydrostatic Equilibrium for liquids) and ‘EE’ (Electrostatic Equilibrium for gasses).
This looks a likely place to improve understanding, though I’ve not seen the entire site:
http://www.physicsclassroom.com/class/estatics/Lesson-4/Electric-Fields-and-Conductors
A molecule with a ‘lesser mass’ occupies the same ‘space/volume’ as a molecule with a ‘greater mass’ for gasses. This isn’t so for liquids which still have extant covalent electrons. The ‘extra space’ for the ‘lighter molecule’ within a ‘gaseous medium’ is generated by the ‘inertia value’ of each component molecule, their ‘inertia value’ is always ‘constant’ for ‘EE’ to exist. This implies that the ‘lighter molecules’ possess/exhibit ‘greater velocity/speed’ than the ‘heavier molecules’ (feel free to superimpose ‘mass comparison’ for ‘weight comparison’ in my prose 😉 ).
This poses more questions for kinetics and temperature change. IMHO, the temperature is set/governed by the more massive molecules (simply because of ‘size’ being more ‘energy concentrated’), but I may well be wrong. ‘Average molecular inertia’ is the ‘average’ that dictates a recorded temperature at a given pressure, but this is a ‘far cry’ from the ‘great circulations’ that we’re supposed to be discussing here. However, it’s of importance for a better understanding of our/Earth’s atmosphere. 🙂
Best regards, Ray.
suricat says: May 6, 2016 at 2:17 am
What! No response to my post yet!
I expected a plethora of insults that, in effect, didn’t follow my posting.
Where are you guys?
Best regards, Ray.
suricat says: May 16, 2016 at 2:18 am
“Where are you guys?”
If after almost one year and over 2250 posts you’re not even aware of the subject of this thread it is pointless to continue any discussion.
“but this is a ‘far cry’ from the ‘great circulations’ that we’re supposed to be discussing here.”
The thread subject is “Atmospheric convection – what does it mean?”,
not Global Circulation Cells.
Roger Clague says: May 7, 2016 at 6:42 pm
“In sections 1.3 and 1.4 there are two different explanations of buoyancy.”
1.3 When the two forces do not quite balance, the difference is the buoyancy force. This is the upward or downward force exerted on a parcel of air arising from the density difference between the parcel and the surrounding air.
1.4 A moist atmosphere that includes water vapour is slightly less dense than a dry atmosphere at the same temperature and pressure; because the vapour displaces a corresponding amount of the other gases per unit volume and the molecular weight ratio of water vapour to dry air is 0.62:1*. Thus a parcel of moister air is slightly more buoyant than surrounding drier air.
In both parts density difference is the deciding factor for buoyancy.
So your point is??
Ben Wouters says:
May 18, 2016 at 4:09 pm
In both parts density difference is the deciding factor for buoyancy.
Yes, but they are different kinds of density.
In 1.3 density is mass/volume and in 1.4 density is number of molecules/volume
For gas 1.4 is correct because as 1.4 goes on to say:
As the water vapour molecule occupies about the same space as the dry air molecules it displaces, so air density (mass per unit volume) decreases a little
Gas pressure is caused by number density not mass density.
I agree with
suricat says:
May 8, 2016 at 1:10 am
There are differences between ‘HE’ (Hydrostatic Equilibrium for liquids) and ‘EE’ (Electrostatic Equilibrium for gasses).
A molecule with a ‘lesser mass’ occupies the same ‘space/volume’ as a molecule with a ‘greater mass’ for gasses. This isn’t so for liquids which still have extant covalent electrons.
Ben Wouters says: May 18, 2016 at 4:03 pm
“If after almost one year and over 2250 posts you’re not even aware of the subject of this thread it is pointless to continue any discussion.
“but this is a ‘far cry’ from the ‘great circulations’ that we’re supposed to be discussing here.”
The thread subject is “Atmospheric convection – what does it mean?”,
not Global Circulation Cells.”
I concur, but if you retrace your steps to the start of ‘this’ current thread you may realise that OB proffered a ‘conundrum’. Your ‘thermals’ don’t ‘convect’ by ‘convection alone’ (unless you permit ‘advection’ to wear the label of ‘convection’ as well)!
My ‘aim’ here is to ‘show you’ how and why ‘convection, per se’ is only a ‘small’ part of the influence for atmospheric circulation. ‘Convection’ works fine in a ‘liquid fluid’, or even a ‘specific gas fluid’, but a ‘mixed gas’ with a ‘partial latent potential’ is another beast. Why wouldn’t I question your arrogance on understanding such a complex configuration?
‘Temperature change’ doesn’t even cover it Ben!
Ray.
Roger Clague says: May 19, 2016 at 11:50 am
I both concur and appreciate your participation in this thread Roger.
To quote both yourself and Ben:
“”In both parts density difference is the deciding factor for buoyancy.”
Yes, but they are different kinds of density.””
I’d say that there are ‘different kinds of buoyancy’ for gasses, but because their/this mutual ‘atractor’ (buoyancy) provides a similar outcome for an ‘opposing density aspect’ isn’t the same as saying that ‘density per se’ provides/initialises ‘convection’.
However, this is true for an atmosphere that’s in electrostatic equilibrium, but Earth’s atmosphere is far from that. ‘WV’ (Water Vapour [H2O]) molecules possess less mass than other molecules that make up Earth’s atmosphere, but occupy ~the same volume as other molecules! This poses the question of ‘how does WV behave within the atmospheric gas mix’?
IMHO WV ‘advects’ other atmospheric gasses towards a ‘greater altitude’ with its presence in the ‘gas mix’, moreover, the continual production of WV at Earth’s ‘surface’ is a ‘positive forcing’ for the ‘advection’ of Earth’s atmosphere towards a greater altitude.
This isn’t ‘convection, per se’, but a ‘negative’ to its generally understood behavioural effect. A ‘positive’ to this aspect would be the ‘downdraft’ created by ‘falling rain’ from aspects usually not discussed for these scenarios on ‘convection’ (circulations generated by ‘falling rain’ are concluded to be ‘advective’ [Huh? Isn’t this part of the returning atmosphere from a ‘convective cell’?]).
I’ll leave you with these ‘thoughts/considerations’. There are many ‘discrepancies’ between ‘macro’ and ‘micro’ observations. 🙂
Ray.
suricat says:
May 23, 2016 at 4:05 am
I’d say that there are ‘different kinds of buoyancy’ for gasses,
There are different causes of buoyancy. Heat or mass density. Both causes should be explained with one physical mechanism.
How does Hydrostatic equilibrium theory(HE) explain buoyancy?
http://www.recreationalflying.com/tutorials/meteorology/index.html
section1.3
As the pressure decreases with height so, in any parcel of air, the downwards pressure over the top of the parcel must be less than the upwards pressure under the bottom. Thus within the parcel there is a vertical component of the pressure gradient force acting upward. Generally this force is balanced by the gravitational force, so the net sum of forces is zero and the parcel floats in equilibrium. This balance of forces is called the hydrostatic balance. When the two forces do not quite balance, the difference is the buoyancy force.
These forces are outside the parcel. They are caused by the weight and p/h gradient of the whole column of air.
The density of the parcel will not change the forces on it. It will still float in equilibrium. HE theory cannot explain buoyancy.
This is the upward or downward force exerted on a parcel of air arising from the density difference between the parcel and the surrounding air.
But the previous sentence says buoyancy is caused by the weight and p/h gradient of the air column.
I agree buoyancy is caused by relative density of the parcel and surrounding air. But this is very different from weight and p/h gradient of the column of air.
Relative density is caused by the molecular properties of the gas.
HE theory using weight and non-molecular parcels fails to explain buoyancy
Molecular theory using mass, number and velocity does explain buoyancy.
Roger Clague says: May 29, 2016 at 7:58 am
I concur with what you say, but disagree. There is a/an ‘inertia’ moment that isn’t addressed, together with an anomaly that I’m currently experiencing with ‘Note Pad’ in ‘win 10’.
I’ll get back later when I can respond with accuracy.
Ray.
Roger Clague says: May 29, 2016 at 7:58 am
“suricat says:
May 23, 2016 at 4:05 am
I’d say that there are ‘different kinds of buoyancy’ for gasses,
There are different causes of buoyancy. Heat or mass density. Both causes should be explained with one physical mechanism.”
IMHO they can’t. ‘Mass density’ is both subject to the ‘gas mix’ for the region and ‘advection’ is confounded with this property, and ‘thermal reactance’ is subject ‘solely’ to the local temperature. Much ‘energy’ and ‘density change’ is tied to the ‘phase change’ of H2O.
This is a ‘test’ for an old version of Lotus Word Pro! If this ‘works’, I’ll use it in future and complete my response.
Ray.
suricat says:June 3, 2016 at 2:30 am
The ‘line-space’ is bad, but the post got through without the problem of no ‘line-wrap’ that I experienced with ‘Note Pad’.
I’ll get back later with my full response Roger.
Ray.
suricat says: May 30, 2016 at 1:35 am
“Roger Clague says: May 29, 2016 at 7:58 am
I concur with what you say, but disagree. There is a/an ‘inertia’ moment that isn’t addressed,”.
We need to work through the atractors that are involved to realise this.
Let’s take this from the minimal aspect of energy to a gas/atmosphere.
At ‘absolute zero’ we have ‘no observation’ of events for ‘any’ compounds (an Eigenstate exists). However, at temperatures above this state of mass, observation is possible.
Above this/that ‘state’ we observe that ‘EM radiation’ (‘electro-magnetic radiation’ [not to be confused with ‘particle radiation’]) causes motion to any ‘molecular collections of atoms’ (compounds) in accordance with their individual ‘electrostatic potential’ (this is the birth of ‘The Kinetic Theory of Gasses). This ‘motion’ is generated/initialised by the ‘electrostatic-magnetic potential’ generated by the ‘EM’ (electro-magnetic) ‘insolation’ from Sol (our Sun)!
This is an introduction into the world of “kinetics” for those who have an interest. Switch off if you want to.
Others need to be patient, I’ve problems/obligations elsewhere.
Ray.