Interesting correlation: Sunspots vs Specific Humidity

Posted: August 8, 2010 by tallbloke in solar system dynamics

I graphed specific humidity since 1940 against sunspot number averaged over the solar cycle, and got this surprising result:

Specific Humidity vs Sunspot number

Since sunspot numbers don’t correlate so well as this with temperature, it raises the question of what it is which controls specific humidity in the atmosphere. How might the solar flux be affecting humidity?

Wikipedia says this about specific humidity:
Specific humidity is the ratio of water vapor to air (including water vapor and dry air) in a particular mass. Specific humidity ratio is expressed as a ratio of kilograms of water vapor, mw, per kilogram of total moist air mt .

That ratio can be shown as:

SH = mw / mt

Specific humidity is related to mixing ratio (and vice versa) by:

SH = omega / 1+omega

omega = SH / 1 – SH

Update: The correlation looks even stronger with the sunspot numbers smoothed at the length of the Earth-Venus cycle, 96 months. It also looks strong at around 82 months, half the length of the Jupiter-Uranus synodic period which coincides with flooding events, as noted by Ulric Lyons in comments.
Specific Humidity vs Sunspot numbers 96 month

Divergences coincide with el nino events and the rebound la nina aftermath.

Update 2: The Specific Humidity data on the above graphs is for the atmosphere at around 30,000 feet. Just a bit higher than Mt Everest, and around the height airliners fly at. It is also around the height of the tropopause: the troposhere – stratosphere interface, at the poles.  The curves look different at other altitudes, so our solar correlation seems to be specific to this level in the atmosphere. This might give us a clue as to the ways energy is propogated in the climate system.

  1. Stephen Wilde says:

    An active sun seems to be associated with a poleward movement of the jet streams. That allows an expansion of the equatorial air masses with a reduction in the size of the polar air masses and an increase in evaporation from the oceans resulting in higher global humidity.

    A quiet sun seems to be associated with an equatorward movement of the jet stream which forces a contraction of the equatorial air masses with an expansion of the polar air masses and a decrease in evaporation from the oceans reulting in lower global humidity.

    The effect is supplemented by the albedo changes as the cloud banks along the jet streams and ITCZ shift latitudinally and clouds cover larger or smaller areas of ocean.

    However that is only half the story because oceanic effects are more powerful in the short term than solar effects.

    The periods when the correlation fails to work are times when ocean cycles are forcing changes in the size of the equatorial air masses against the weaker solar effect.

  2. tallbloke says:

    Hi Stephen,
    yes, that seems like a very plausible explanation. More support for your hypothesis! It also seems to support my hypothesis that at times of high solar activity (1955, 1985), the forcing of heat down into the ocean suppresses the surface temperature and lowers the rate of evaporation – fewer el ninos near solar max. And when the solar activity is low (1965-1975), heat-energy resurfaces and raises SST, increasing evaporation and raising humidity So we get an anticorrelation in the short term, but a positive correlation in the longer term. These conflicting tendencies being due to two different effects of the incoming solar radiation on the oceans and atmosphere.

    Good stuff!

  3. Tenuc says:

    Good graph TB.

    Extra water vapour = more clouds = less insolation = lower SST = reduction in humidity.

    Seems some sort of feed-back mechanism at work?

    What does it look like if you over-lay SST on the same graph?

  4. tallbloke says:

    Hi Tenuc,
    it’s not that simple, because it seems high solar activity reduces cloud too (Svensmark effect?), hence the amplification of the solar signal observed by Nir Shaviv. Here comes the graph you requested, but with solar cycles (blue) averaged over 12 months rather than 11 years, and with global temp (red) thrown in with southern hemisphere SST’s (green). SPecific humidity still in purple.

    Interesting to see the individual solar cycles correlating with the rises in specific humidity quite well, yet when the sunspot number is high over longer term, there is a fall in specific humidity. This needs thinking about, there is an important control mechanism at work here.

  5. tallbloke says:

    I just got a much better correlation smoothing the sunspot data at 100 months:

    And even better at 96 months, the Earth Venus cycle length. Hmmmmm 🙂

  6. Ulric Lyons says:

    Most of the big floods in the last 1500yrs of written UK and Chinese records happened at Jupiter/Uranus syzygies, that`s the 6.9yr signal in your last graph. If it`s Saturn opposite Jupter and Uranus, well that marks some of the very largest, including written dates from Babylon. The J/U syzygies work positive with cyclone activity too.

  7. tallbloke says:

    Thanks Ulric, There are major floods right now in Pakistan, at this conjunction of Jupiter and Uranus.
    The Sunspot numbers averaged over 6.9 years looks pretty good compared to specific humidity too. Probably a bit too good for NOAA’s liking, because their graph looks completely different from the same reanalysis data:
    NOAA specific humidity

    It doesn’t look like it’s just a different smoothing value either.
    H/T Araucan on WUWT for that observation

    Update: Mystery solved, the above graph is for a different pressure. The labelling from NOAA is misleading.

  8. “Elementary my dear Watson!”. That shining ball up there, big chief says, heats the seas, and when seas are hot big vapor ascends to the heavens….LOL
    This is a fact, used to be taught in the third grade, now denied by global warmers when they say global warming melts glaciers 5000 meters above the sea level-where temperatures are always below freezing point-and all that is needed for them to grow is humidity.

  9. tallbloke says:

    It’s worth noting that 1951-’52 & ’53-’54 were el nino years. So was 1998, followed by a couple of colder winters and a big la nina.

    Also worth noting is Roy Clark’s observation that drier soil means higher surface temp readings, due to less evaporation.

    We are onto something interesting here.

  10. Tenuc says:

    Thanks for the graph combining specific humidity and SST. Seems to be a change in the correlation after 1990, I wonder why? Perhaps wind-strength is also a factor?

    The enthalpy of evaporation removes energy from the surface and transports it into the atmosphere. where it can radiate away to space more easily. Good observation from Roy Clark that the absence of this energy transport mechanism results in high surface land temperatures.

    Plenty going on here to ponder about.

  11. From the above quoted article:
    As the earth passes any of the outer planets heliocentricly, the increase in magnetic flux felt by the Earth due to the outer planet(s) increases the charge gradient from poles to equator, and adds to the displacement volume of air mass from equator to mid-latitudes and the total ion charge gradient across frontal boundaries, and the moisture content in the air masses to carry positive ions, which requires molecules missing valance electrons

  12. tallbloke says:

    Hi Adolfo,
    as you know, Richard Holle is a regular contributor to this site. Hopefully he’ll come along and explain more about this in relation to the ongoing discussion. Thanks for pointing it up.

  13. tallbloke says:

    Tenuc, there is wind strength graph on the Roy Clark thread. Take a look.

  14. Tenuc says:

    Thanks TB. I missed the update to Roy’s thread. Looks like variation in wind speed has a large effect on rate of evaporation and subsequent energy transport.

    A further thought; how much cooling do tornadoes cause and could these be part of the link to changes in weather regime caused by solar activity?

    My thought is that twisters are a form of ultimate safety valve which kicks in when the earth has too much energy (not necessarily just heat), and rapidly vent the excess high into the stratosphere. Both tornadoes and sun spots (vortices) display EM effects and perhaps provide the same function of energy dispersal?

  15. tallbloke says:

    Tenuc, short answer is, I dunno. Twisters are the small high velocity photogenic counterparts of big cyclonic and anticyclonic weather systems. Much weaker in energy terms than big storms, but maybe more of them make up for that?

    Would the EM effects be weak manifestations of a dynamo effect? Surely an effect of the wind supplied energy rather than a driving force? I didn’t hear of anyone being electrically burned by a twister.

  16. DirkH says:

    If specific humidity controls the H20 Greenhouse effect, periods of high humidity could lead to an accumulation of heat – if this is so, there should be a correlation of the integral of the humidity with the “global temperature”. The higher parts of the two curves happen during the warming intervals of the 20th century.

  17. tallbloke says:

    Just like humans keep warm by several different methods; hairs go up on arms, shivering stimulates muscle heat production, withdrawal of heat to body core etc, the planet has various mechanisms for maintaining a steady temperature too. Energy storage and release from oceans, changing cloud albedo, varying amounts of water vapour, storm seasons, flora colouration, snow cover etc etc.

    You don’t need to subscribe to a ‘Gaia hypothesis’ to appreciate the various mostly negative feedback mechanisms which come into play. Specific humidity is just one among many such mechanisms. If it correlated well with global temperature in the 40’s and 80’s, it isn’t doing so well now. At the moment, it is high ocean heat content which is keeping Earth warm while the sun sulks.

  18. DirkH: periods of high humidity could lead to an accumulation of heat
    Unless you include in that “humidity” the seas’ water nothing would change. The volumetric heat capacity of air is 3227 times less than water. There is no “heat piggy bank” possible in the atmosphere.
    BTW, this I am writing it from a high humid SH place where to read about such a phenomenon is, to say the least, a sadistic idea. The more hummid the atmosphere the fastest the cooling of your body. It is like being inmersed in a bathtub filled with cold water.

  19. DirkH says:

    Adolfo, i thought about storage of heat in the oceans but that would introduce a rather long lag time i suppose – or maybe surface waters can act as short term storage.

    I think this correlation discovered by tallbloke is much too good to be spurious. As H2O is the dominant player, it makes all sense in the world to pursue this further. We’d need to have a good causal chain to link it to temperatures, still. That’s why i think integrating could be a possible way to get there.

  20. DirkH says:

    ….but while i say “surface waters”… El Ninos and La Ninas are phenomena of upwelling of deeper waters – and the El Ninos disturb tallbloke’s correlation. So the SST must play an important role. The surface waters must be the short term storage; an El Nino disturbs the balance temporarily.

  21. tallbloke says:

    Hi Dirk, good idea with integrating the data, if we can find the right numerics since NOAA seem to have ‘adjusted’ everything.
    It works for me with sunspot numbers on my post
    The result from the humidity data should be similar, since the correlation is good.

    The El nino’s release heat-energy which is either in the pacific warm pool, a subsurface body of warm water which is up to 100m deep, or in a ‘modoki’ el nino, when heat leaves the ocean worldwide but in less extreme temps. It’s a somewhat mysterious process but the layers of sun warmed water are stratified and so el nino is followed by La Nina as cold water upwells up the Chilean side of south America and head out with the Humboldt Current.

    Full blown PWP el nino releases and enourmous amount of heat from a relatively small area, sending humidity levels soaringthe nino 3.4 locality. The water vapour traps the heat and the atmospheric currents spread it far and wide. Modoki El nino like th one we just had can also raise temp, but the ocean loses a lot of it’s heat content in the process, as the cooler air alows more heat to space.

  22. Cement a friend says:

    Tallbloke, interesting stuff. Comment by Stephen Wilde also appreciated.
    I hope you do not mind me (possibly) using one or two of your graphs in a talk I am preparing to present to a group at the local U3A (university of the third age). Older people have lots of experience but still want to learn.
    Keep strong

    [reply:] Sure. Please mention this blog and let us know if your presentation goes online so we can link to it. Cheers.

  23. The sun / earth relationship is electromagnetic in nature the homopolar generator effects as the magnetic coupling increases into the Earth increases the pole to equator charge gradient,
    Negative at the pole and positive on the equator / ITCZ. This drives positive ions into the atmosphere along the ITCZ yielding the increased relative humidity, because the additional positive ionic charge increases the mutual static charge based repulsion between fine water droplets, stopping further condensation, thus loading the moisture content higher than the temperature alone could maintain.

    Tornadoes form when the lunar declinational tidal meridional flows move these areas of positive ionization, poleward as the peak of the positive component of the charging cycle starts to shift back toward the equator. The +ions are not free electrons like Negative ions are, so the dense moisture laden positive charged air masses close to the ground have to be physically pulled into the rapidly condensing precipitation on the funnel and wall cloud surfaces.

    That is why the peak production of tornadoes forms just past maximum culmination lunar declination for about three days both primary and secondary bulges, and around summer solstice as the moon crosses the equator. When the earth is having a heliocentric conjunction with other planets the additional charge builds up to the point of closest alignment, then discharges for the next 7 to 10 days. If these separate cycles interact in a cumulative way the process is enhanced and the number and intensity of the tornadoes increases, and decreases the net effects when out of phase.

    Tornadoes are the atmospheric storm process for the spring / summer charge process, hurricanes and tropical storms are the discharge process from July to November, the same charge gradient forces still apply but it is a general discharging pattern overall.

    So in answer to your original proposal the same applies to long term charge shifts, long term slow gains in charge gradient will increase the total moisture content of the atmosphere that cannot rain out until the gradient shifts the other way, short or long term hence derechieos, and flash floods (rapid sudden discharges) after long droughts that look like it could rain any time but don’t (Charging at a good steady pace).

    The production of TS Bonnie and Colin have been effected by the lack of decrease in the homopolar fields because the coupling coming up on Neptune August 20, Uranus and Jupiter on the 21st-24th conjunction of both to each other then Venus in early(?) October, is balancing the normal annual discharge post summer solstice. To where they, Bonnie and Colin just effected the transport of positive ions in the form of moisture into the mid-latitudes for later release during the post heliocentric conjunction discharge phases, in steps as the Earth passes the outer planets.

    I will be plotting graphs of the relationship between the lunar declination and Hurricane production by ACE numbers as soon as I get a high speed connection, It should be illuminating to see the past annual patterns, referenced to the lunar declination with the Synod conjunctions shown as a vertical line on the day of each, plotted for the years of record. You might find it interesting to look at the relative humidity numbers in the same format

    I think the relationship between the compounding of the solar strength, lunar declination, and heliocentric conjunctions, should be easily viewable.

    So currently you should see an increasing background level of global humidity that is stuck not being able to get back to the ground, because the ionic charge gradient is up and stable at this time. The same should apply with long term solar cycle period length, levels of sustained background charges, due to those long term effects as well.

    By the way I have noticed the solar flare / spots seen in the image Lief mentioned;

    follow the lunar declination, North solar hemisphere when Moon Maximum North, Southern solar hemisphere when moon Max South, with weak spots spread across the solar equator as the moon crosses the Earth’s equator. (NO connection my a$$!)

  24. tallbloke says:

    Richard, great post.
    So what is happening in your opinion? Is the Moon acting as a focal point for energy travalling back from the Earth towards the Sun, directing the energy onto the Solar surface to produce effects?

  25. Richard Holle says:
    August 10, 2010 at 4:37 am
    Surprising assertion. Perhaps it would seem too esoteric for you, but if you read the chapter 9 of:
    You’ll see the octave of worlds ending in the moon.

  26. tallbloke says:

    Adolfo, there is a reason the chapter number is 9. Ouspensky is making a reference to the numbering system used for the planets by alchemists and astrologers. If you look at the symbols used for the planets, they start with a 3 for saturn, a 4 for Jupiter, a 5 for Mars. These are the slow moving planets outside the Sun, which is 6. Then comes Venus – 7 and mercury – 8, and finally the swiftest moving body from a geocentric perspective, the Moon -9.

    While I have an interest in these earlier knowledge systems as a historian of science and believe that some nuggets of valuable information lurk in there, I keep that seperate from my quantitative work on this blog. If there is a specific reference which you find relevant, by all means put it forward, but I’d be grateful if we can seperate vague alliterations from testable hypotheses as far as possible.


  27. DirkH says:

    Richard Holle: Interesting ideas. Recently i wondered about the electric charge of cloud droplets and googled around. Some experiments with femtosecond laser pulses are underway to sense the (tiny) charge. IOW, they are charged, we only don’t know by how much yet or what rules apply. And we also know about the vertical voltage gradient in the atmosphere, i think about 250,000 V from the ground to the stratosphere. So it looks to me like electrical fields definitely play a role in cloud formation, cloud height and shape.

  28. I was in the middle of this post and the power went out due to a series of thunder storms passing through, back on line and hope to remember what I said the first time…

    The Earth / moon system is magnetically coupled to the sun, only the changes are apparent, because the background levels are stable they are not detectable as a result of the way we long term average out measurements of magnetic fields strength. So only the shifts are viewable, much as when at the beach we only see the tidal movement if there all day, if less than a hour just the waves breaking on shore.

    Or notice the hum due to the ripple noise on top of the voltage, from the DC power supply for the radio, the larger the ripple the louder the hum.

    In plasma discharges the focus of the bulk current, follows the paths of least resistance, as the North / South movement of the moon acts as a focal point (moon is outside of the earth’s magnetosphere most of the time) for the solar wind interface the point of highest current follows the path of least resistance, I think the sun’s magnetic fields extend the flares, spots, CMEs, along these paths of least resistance, which drives the lunar declinational movement of the Earth Moon system.

    So it follows that shifts in lunar declinational tides in the atmosphere are in phase with the surges in currents seen inducted into the geomagnetic fields, and this is just an easy way of viewing the ongoing background process. The surges are more easily seen as the rapid flux changes in CMEs, where as the background fields just stay centered on the earth’s position, and shift solar departing point to the most active area closest to the path it will follow.

  29. DirkH; years ago I looked at the research on the relationship of static charge on nebulized moisture droplets relative to the vapor pressure, and size of droplet, there was a body of research on this back in the 80’s, the jist was that the higher the charge the smaller the resultant droplet size, because of a surface area to volume ratio the larger drops would fragment to keep the charge per unit area of surface consistent, when increasing the charge, and allowed them to condensate into larger droplets more easily when the charge was dropping Negative going neutral.

    As seen when lightning strikes, there is most often a sudden uptick in rain drop size, and total rainfall for short periods of time.

  30. Paul Vaughan says:

    Anyone have the links to the 2 specific humidity data sets?

  31. Ulric Lyons says:

    @Richard Holle says:
    August 10, 2010 at 4:37 am

    “follow the lunar declination, North solar hemisphere when Moon Maximum North, Southern solar hemisphere when moon Max South, with weak spots spread across the solar equator as the moon crosses the Earth’s equator. (NO connection my a$$!)”

    I`ll keep an eye on that.

  32. tallbloke says:

    “As seen when lightning strikes, there is most often a sudden uptick in rain drop size, and total rainfall for short periods of time.”

    Brilliant observation! I’d noticed it myself, but never made the electrical ‘connection’. I suppose I should be thankful I’ve never been electrically connected to lightning. 🙂

    What you are saying about path of least resistance makes sense. I’ve been thinking along similar ‘field lines’ myself about the pathways solar magnetic ‘ropes’ might follow in the IMF.

    Do you think the Earthward ropes might use the Moon as a ‘staging post’ when the Moon is between Earth and Sun?

  33. tallbloke says:

    Paul, I found the NCEP re-analysis site with a plot making facility for world maps with SH overlaid. I’m still hunting for the time series. More soon.

    Update: Here you go:

  34. Verity Jones says:

    Great thread. I saw this when you first posted it but haven’t had time to comment. Humidity seems to be one of the most interesting parameters in the whole warming story and one of the most complex also. I’ve been thinking about this for some time although haven’t managed to do much analsysis or anything concrete yet

  35. tallbloke says:

    Hi Verity and welcome back.
    There are a couple of previous WUWT posts which touch on the same subject, which I came across while tracking down the data:

    One of the interesting aspects is that the NCEP re-analysis uses a model to assist it’s untangling of radiosonde data. They must have got something right to get a match this good to solar activity without intending to. It would be interesting to know more about the model parameters…

    Relative humidity has varied little, so specific humidity has to fall as temperatures rises. The 300mb level is within the tropical upper troposphere, so this may indicate some small amount of increased greenhouse effect there. I need to make time to do some analysis of the higher latitudes in comparison to the tropical latitudes to get a better handle of the differences caused by the crossing of the tropopause by the 300mb pressure level. This should be possible with the link I provided to Paul above.

    The rise in specific humidity at low altitude in recent years indicates to me that the surface temperature dataset is wonky…

  36. Tenuc says:

    Richard Holle says:
    August 10, 2010 at 4:37 am
    “The sun / earth relationship is electromagnetic in nature…”

    Good post Richard, some great stuff here!

    I have always been puzzled about how charge separation can occur inside a cloud prior to a thunderstorm, without an internal short circuit happening before sufficient charge builds up to allow lightening to occur, standard explanation of how lightning works here:-

    However, I’m not convinced by the NOAA explanation – any ideas?

  37. tallbloke says:

    This paper might interest Stephen Wilde particularly:

    Hadley Circulation as a Modulator of the Extratropical Climate
    Arthur Y. Hou
    Data Assimilation Office, Laboratory for Atmospheres, NASA/Goddard Space Flight Center, Greenbelt, Maryland

  38. Paul Vaughan says:

    tallbloke, thanks for the link to Lucia’s article on these patterns at The Blackboard. I’ll dig through the pile of links from there to try to locate the data (delays, delays, & more delays, … & so little free time…)

    One thought on your graphs: Do you remember some recent articles on solar cycle UV-related troposphere volume variations? That correlation was clear & unchallenged.

  39. Paul Vaughan says:

    The data is in an obstructionist format. Anyone know of any plain-text alternates?

  40. Paul Vaughan says:

    Sorry, that should have been thermosphere, not troposphere (if I remember correctly).

  41. DirkH says:

    Re electric charge and droplet size; some things i found:
    In 1882, Lord Rayleigh theoretically estimated the maximum amount of charge a liquid droplet could carry;[2] this is now known as the “Rayleigh limit”.
    His prediction that a droplet reaching this limit would throw out fine jets of liquid was confirmed experimentally more than 100 years later

    Evaporation can make a droplet shrink until its charge requires it to explode; a Coulomb explosion.,_3rd_Baron_Rayleigh

  42. More good reading to do I can barely get around to the several blogs i read daily and still read new things like this, [curse you, may you live in interesting times].

    Some days it is hard to be expansive thinking and stay on track.

  43. JKrob says:

    “As seen when lightning strikes, there is most often a sudden uptick in rain drop size, and total rainfall for short periods of time.”

    I hope you are not implying that the lightning strike influences the raindrop size/volume. I’ve seen that ‘lightning causes raindrops’ line put out before at other places but with no real hypothysis (sp?) to go along with it. Think about it – any droplets formed by a thunderclap shockwave or anything like that would only be a mist-like as seen in typical explosive shockwave clouds recorded on videos. Also, no shockclouds have ever been recorded on the many vidoes of close-by lightning strikes.

    I think it is the other way around – the rainshaft falling from the cloud acts as a conductive channel for the lightning strike. The rainshaft (which, by observation, is of a heavier volume than the surrounding area) is falling from the cloud causing a more conductive channel reaching closer to the ground. Once it reaches a specific point close enough to the ground, the lightning step leader is close enough to make the final ‘leap’ and contacts the ground, completeing the circuit and the lightning strike is seen & the thunder heard. The raindrops are still falling at their terminal velocity (which is much slower than the lightning strike speed) and after a few seconds following the lightning strike, the raindrops are observed at the surface.

    Now, doesn’t that make better sense? 😉


  44. JKrob says:

    Stephen Wilde says:

    “An active sun seems to be associated with a poleward movement of the jet streams. That allows an expansion of the equatorial air masses with a reduction in the size of the polar air masses and an increase in evaporation from the oceans resulting in higher global humidity.

    “A quiet sun seems to be associated with an equatorward movement of the jet stream which forces a contraction of the equatorial air masses with an expansion of the polar air masses and a decrease in evaporation from the oceans reulting in lower global humidity.”

    That connection may be through the AO (Arctic Oscillation)…in the northern hemisphere anyways. The normal global pressure distribution favors high pressure at the equator and low pressure at the poles with the jet stream in between progressing west-to-east. With the AO in a positive mode, the upper-atmospheric pressure at the north pole is below average which favors the lower pressure however, with the AO in it’s negative mode, the same area at the north pole has above average pressure which shifts the jet stream southward and enhances jet stream blocking patterns (which has been seen this past winter *and* this summer over the Asian continent (persistant heat/drought over western Russia & cool weather/flooding over Pakistan & eastern Russia).

    Upper atmospheric procceses (heating/cooling) are known to be modulated by the solar wind (active Sun – warmer stratosphere, inactive Sun – cooler stratosphere). This may modulate the QBO (Quasi-Bianual Oscillation) around the mid-latitudes which may propogate up toward the polar region & modulate the AO/AAO.

    Just some thoughts,

  45. Stephen Wilde says:

    JKrob says:
    August 19, 2010 at 7:01 pm

    Thanks Jeff, you are on the right track I’m sure. Elsewhere I have explained why I see the polar oscillations to be a response to solar induced changes in stratospheric temperatures.

    However, an important point, it seems that the stratosphere must cool when the sun is more active and warm when the sun is less active to achieve the observed outcome.

    I know that is heretical but it must be so because I cannot see how a strengthening of the inversion at the tropopause (warming stratosphere) could do otherwise than increase atmospheric pressure below the tropopause at the poles yet we see that when the sun is less active. A stronger inversion must oppose upward energy transmission whereas a weaker inversion must facilitate it, obvious really.

    Sio, I think something is wrong with the standard assumptions about the net effect of more solar activity on ozone quantities.

    That opens a can of worms about CFCs too but, hey, don’t shoot the messenger.

  46. DirkH says:

    JKrob says:
    August 19, 2010 at 6:35 pm
    “[…]I hope you are not implying that the lightning strike influences the raindrop size/volume. I’ve seen that ‘lightning causes raindrops’ line put out before at other places but with no real hypothysis (sp?) to go along with it. ”

    Okay, i’ll explain once more: The lightning discharge leads to a drop of negative charge in the lower layer of the cloud. Less charge means that big drops don’t have to undergo a Coulomb explosion and can stay stable. Collisions of drops can lead to the formation of bigger drops now. Before the lighting discharge, the large drops would have had too much negative charge; this would have forced them to undergo a Coulomb explosion. Also, smaller droplets would repel each other so larger drops can’t even form in the presence of a lot of negative charge.

    For very small droplets, the viscosity of air is relatively high and they can stay airbound; big drops can overcome this viscosity and fall. So after a lightning discharge, big drops can form and a downpour occurs.

    Here is a nice experiment that demonstrates the electrostatic force on water droplets:

  47. tallbloke says:

    Stephen, another heretical thought for you which might confirm what you are saying. As you can see from the updated graph at the top the green specific humidity curve goes up with the sunspot number. This is at the 300mb level, right up around the tropopause. That means more water vapour trapping outgoing heat at solar max. That will cool the stratosphere more than the extra watt/m^2 solar cycle variation will warm it.

  48. JKrob says:

    DirkH says:

    “… Less charge means that big drops don’t have to undergo a Coulomb explosion and can stay stable. Collisions of drops can lead to the formation of bigger drops now. Before the lighting discharge, the large drops would have had too much negative charge; this would have forced them to undergo a Coulomb explosion. Also, smaller droplets would repel each other so larger drops can’t even form in the presence of a lot of negative charge.”

    OK…interesting…however, (I’ll try to put this respectfully) I don’t think you have the correct grasp of cumulo-electrodynamics (neat word, eh? I just made it up for lack of any other proper way to describe what we are talking about).

    First off – as to “Coulomb explosions”, for Wikipedia:
    “A Coulomb explosion is a mechanism for coupling electronic excitation energy from intense electromagnetic fields into atomic motion. The atomic motion can break the bonds that hold solids together. When done with a narrow laser beam, a small amount of solid explodes into a plasma of charged atomic particles.”

    There are *NO* intense electromagnetic fields in cumulus clouds. There are intense electrostatic fields but even these are spread over a fairly large area of the height of the cloud & in pockets within the cloud.

    Second, the electrostatic charges built up within the cloud are mainly from the *solid* particle collisions (snow, grapule, hail, etc.) between the updrafts & downdrafts within the cloud above the freezing level & not from the liquid drops. There is no rubbing between drops of water to create the charge separation like with what happens with solid particles. That is why warm but heavy showers do not have much if any lightning but snow squalls can. If the freezing level is high & the majority of the precipitation process collisions are below the freezing level, even with a good bit of turbukence, there will be little or no lightning. However, low-toped snow squalls which develop over the Great Lakes, being composed completely of frozen particles (snow flakes) can have lightning in them (thunder snows). Also, the dry thunderstorms over the desert areas have lightning even though the cloud depth is fairly shallow but it is above the freezing level, it’s moisture volume is mainly ice so the turbulence within can create the charge buildup and produce lightning.

    The same thing applies to lightning seen in volcano eruptions. The ash blown out of the volcano is a solid particle & fairly dry so with the turbulence of the gasses, it builds up an electrostatic charge & you get lightning but you would not get the same effect from a steam only explosion of the same size because they are only liquid water drops.

    There for, with what I have presented, unless you can present evidence of cumulus static charge buildup which actually pertain to cumulus dynamics, with all due respect, I’ll stick to my hypothesis.


  49. Stephen Wilde says:

    Thanks tallbloke.

    That would indeed fit because all along I have said that the issue is differential variability in energy flows over time in different layers.

    I even suggested to Leif Svalgaard that a cooling stratosphere at a time of more active sun could be caused either by energy leaving the stratosphere faster from above or entering it more slowly from below but either way the net effect was greater than the anticipated warming effect of more incoming solar energy on ozone molecules.

    However despite your point the issue is not quite resolved because the increase in water vapour at the tropopause could just as well be a consequence of a faster hydrological cycle as a cause of the cooler stratosphere so we still have a chicken and egg problem.

    At the moment I favour chemical processes whereby a more active sun alters the balance of reactions in the stratosphere so that the cooling effect of more ozone destruction by increased solar activity outweighs the effect of warming from solar particles hitting ozone molecules. The balance of ozone creation/destruction seems to be a largely unknown feature despite the historical assumption that more solar input leads to net warming. The observation that ozone quantities fell during the warmer period and are now recovering fits with that proposition.

    So on balance I think more solar activity leads to faster ozone destruction leading to less ozone and a cooling stratosphere as energy escapes to space faster. That weakens the inversion at the tropopause to increase upward energy flow from the troposphere. The hydrological cycle gets faster with more water vapour dumped just below or at a slightly higher tropopause.

    That sequence fits all the observations but is clearly heretical because it reverses the generally accepted sign of the effect of a more active sun on the stratospheric temperature and on ozone quantities.

    Interesting times.

  50. tallbloke says:

    This is a very interesting line of thought Stephen. I don’t know enough about high altitude atmospheric physics. Does the tropopause rise and fall during the solar cycle? The 300mb level is above the tropopause at the poles, but below it at the equator. Is it possible the point where they cross coincides with the changing jet stream locations? Or some other important feature like the Hadley cell northern boundary? That would be an exciting discovery to make if so, because it would introduce yet another important solar controlled feature of the climate system.

    Despit the fact the absolute amplitude of the solar cycles was faling after the late 50’s peak, the short minima, short cycle length and high cycles up to 2003 mean the average sunspot number was well above the long term average.

    I don’t believe CFC’s from man made objects made much difference to the ozone level. Once again, it’s a matter of scale. So if excess UV destroys ozone, it was “the Sun wot done it.” Stratospheric temp and ozone fell for many years during the warming period up to 2003, and has started to increase again, soon after the sunspot number fell below the long term average in 2003.

  51. Stephen Wilde says:


    The solar effect on air circulation system latitude does not seem to come through on single cycle timescales. I think it is swamped by chaotic variability and the interannual ENSO effects.

    It becomes noticeable from 3 cycles or longer and correlates well with the 30 year phase shifts of the Pacific Ocean region.

    It becomes blatantly obvious however on the 500/1000 year timescales from MWP to LIA to date.

    The tropopause rises with poleward jets and a warming troposphere but falls with equatorward jets and a cooling troposphere.

    The height of the tropopause is undoubtedly linked to the positions of the air circulation systems. That would include the Hadley cells and the jet streams.

    It all fits. I’m just waiting for the penny to drop more widely.

  52. DirkH says:

    JKrob says:
    August 20, 2010 at 12:56 am
    “[…]First off – as to “Coulomb explosions”, for Wikipedia:
    “A Coulomb explosion is a mechanism for coupling electronic excitation energy from intense electromagnetic fields into atomic motion. The atomic motion can break ”

    Okay, don’t know where i read “Coulomb Explosion” in connection with charged water drops, looks like it describes something entirely different from what i mean. I apologize.

    But what actually lets me believe that there is an electric charge in cloud droplets is the fact that researchers are proposing to measure it:

  53. tallbloke says:

    Spector says:
    September 15, 2010 at 1:36 am (Edit)

    As I have stated earlier, I personally suspect that role played by earthshine emitting/absorbing (greenhouse) gases at the tropopause level may be being underestimated as a mechanism for removing convected heat from the atmosphere. I would think that the most important spectra may be those lines that have a 50 percent chance of getting out from that level at the typical temperature of 220 K as I believe these should have the highest relative emissivity.

    The important parameter for measuring how effective convection is as a thermal regulator of surface temperatures would be a determination of how the effective surface temperature, as controlled by the adiabatic lapse rate from the tropopause temperature, would change as a function of the total energy being convected upward. This would account both for tropopause altitude changes and temperature changes with increasing upward convected thermal energy. I do not know if anyone has ever attempted to estimate or determine this.

  54. Ian W says:

    A point I have not seen raised is that the enthalpy of air with a high RH is significantly higher than for dry air. This means that for a given amount of heat dry air will have a higher temperature. The heat content of the a volume of dry air can be 50 times less than that for the same volume of humid air but both volumes would have the same temperature.
    You are showing a significant drop in RH at the tropopause so the air temperature could be high even if the actual atmospheric heat content is lower. This could explain the UAH temperatures being high (hence claim for record hot year) while on the ground cattle are dying in the cold.

    The metric for ‘global warming’ should be atmospheric heat content not temperature.

  55. tallbloke says:

    Hi Ian,
    I have to admit I don’t know how UAH go about combining the data from different heights in the atmosphere to produce their metric, but it does appear as ‘Lower Tropospheric Temperature’, so I’m not sure the action at the tropopause will be relevant to UAH indices.

    Note that my graph is for Specific humidity not Relative humidity.

    Specific humidity is the ratio of water vapor to air (including water vapor and dry air) in a particular mass. Specific humidity ratio is expressed as a ratio of kilograms of water vapor, mw, per kilogram of total moist air mt .

    That ratio can be shown as:

    SH = mw / mt

    Whereas Relative humidity is about volumes, as you show in your comment. Nonetheless, the two are linked, and as you state, moist air will show a lower temperature while containing more energy.

  56. Ian W says:

    One of my concerns about satellite measurements is that they may be using ‘average’ vertical distance for the tropopause rather than the actual tropopause. In the tropics the tropopause may be as high as 70,000ft whereas closer to the poles it will be less than 30,000ft. So a standard vertical distance of say 35,000ft will be mid-troposphere in the tropics but stratosphere close to the poles. Do you know if this is corrected for in the satellite metrics?

  57. E.M.Smith says:

    Nice. Very nice…. I think we’re looking at the same process for opposite ends. I’m looking at the clouds and seeing heat sucked out of the ground and dumped at the tropopause as cloud formation, you are looking at the humidity there and seeing it coupled to solar cycle.

    Put them together, you get “sun driving hydro cycle” and moving heat.

  58. […] years ago I made an interesting discovery. Specific Humidity at the 300mb level (near the tropopause where most radiation to space occurs), […]