First Measurements in Polar Regions

Posted: December 21, 2012 by tchannon in atmosphere, climate, Clouds, general circulation, Measurement, methodology, weather

Image

Atmospheric temperature profile and structure from Antarctica, figure 8 daytime, figure 9 nighttime showing a severe temperature inversion which is misrepresented in radiosonde data, is too coarse. I point out this implies surface cooling failure and is to be expected from a radiative regime which is contrary to the convective, scoured dayside. This also fits with the Leroux MPH which are more prevalent during polar night.

2003 paper

A New Microwave Temperature Profiler – First Measurements in Polar Regions

E. N. Kadygrov, A. V. Koldaev, and A. S. Viazankin
Central Aerological Observatory, Moscow, Russia

A. Argentini, and A. Conidi
Institute of Atmospheric Physics, CNR, Italy

“Temperature inversions are a ubiquitous feature of the high latitude atmospheric boundary layer (ABL). In Polar Regions, the temperature inversion is a complicated phenomenon involving interactions between surface radiative cooling, subsidence and warm air advection. …”
PDF here

The paper discusses the known shortcomings of radiosonde, the infrequent flights, lack of resolution, with polar region data severely affected.

Existing instruments were coarse so a much narrower beam is used 0.5 degree instead of 5.0 degree.

Previously Low Level Noctural Jets have been discussed, poor understood features of nightside. An excellent website was indicated

http://www.windwisdom.net/nllj.htm

Post by Tim Channon

Comments
  1. suricat says:

    tchannon.

    I’m a bit ‘miffed’ by your connection between the linked paper and the linked web site.

    At first sight I thought you were introducing the subject of the ‘Arctic Oscillation’ (AO) by way of ‘mobile polar highs’ (MPHs), but this doesn’t seem to be your ‘modis operandi’. Do you aim to include diurnally generated ‘jets’ (LLJs) as a like phenomenon to MPHs?

    If so, I’m ‘all ears’ because both these phenomena seem to be generated by boundary conditions.

    Best regards, Ray.

  2. tchannon says:

    If I mislead (other than humour) there is never an intent. Perhaps all too often my wording does not connect with others.

    Arctic Oscillation? Nothing to do with that.

    My intent. I am particularly interested in the little researched or data gathered night conditions where a frequent feature are near ground temperature inversions, meaning temperature rises with altitude before then folding over to the usual fall with altitude. Inversions are a very interesting subject anytime anyway.

    The effect I am after in this instance includes in the polar regions literal surface radiative cooling overwhelming heat flow capability from the warmer atmosphere downwards, hence inversion. This is a thin layer. (as in stays a good way below the tropopause)

    Radiosonde typically are only sent up daytime, read out slowly and drift. This is known to give poor results. I am aware of other work but here I can across what looks like a good new tool for giving a fixed location profile at high altitude resolution from close to the ground upwards.

    The MPH forms over polar regions as a thin lens of temperature inversion… nuff said.

    Part of MPH formation is warm air flowing in aloft, air has to come from somewhere for MPH to exit. What is going in in toto, would like to know.

    I pulled in llnj because there are similarities outside of polar regions which add more to the post, is whole large area of great importance when folks fixate on static sunside.

    Actually surcat I have plenty of important material which is not happening because I do not know how to write it. I tend to do information but this rarely connects with others.

  3. michael hart says:

    I think it’s good for the reader to occasionally read things they find abstruse, and have to put in a bit more effort to understand. You won’t always get credit for it, Tim, but it is an important educational tool.

    And no slight or insult is intended to suricat or other commenters.

  4. wayne says:

    I like that tchannon. That’s quite impressive, a full 8 degC inversion at those temperatures and if you want to just take a look using the old SB raw there is at a max of 22 wm-2 leaving that surface. Now if the entire tropics by the cells can send a mere 2.2 wm-2 north to the pole, with 1/10th the area, that completely zeros out that night loss.

    Just look at the various hooks and bends at 50-100 meters. Seems radiation cooling of the surface on low warming, or vice versa, TD from there upward usually. Oklahoma radiosondes show the same pattern, very low hooks.

    Nice info.

  5. Happy Christmas from Fen Beagle…..’We See Things’…
    .http://fenbeagleblog.wordpress.com/2012/12/22/we-see-things/

  6. adolfogiurfa says:

    the temperature inversion is a complicated phenomenon…..My hunch is that there are simple explanations for complicated phenomena,…..but that is neither cool nor “intelligent”.
    So, let us leave complicated matters for complicated souls.

  7. Carl Brehmer says:

    It has been observed that nighttime, near-the-ground temperature inversions are rather common. I have, for example, been doing a study of nighttime temperature inversions using Tallahassee, Fl radiosonde data and near-the-ground temperature inversions are present most nights and vary from 1 – 8C with the max varying from 150 – 750 meters.

    Since, in such inversions, the air near the ground is cooler than the air higher up it is a common belief that the ground itself is cooler still–that the ground is cooling radiatively and drawing heat from the air near the ground creating the inversion. What’s missing from the above study are actual ground temperatures.

    To test this common belief I did a 34 night study of near the ground temperature inversions along with actual topsoil temperatures where I live in Northern Arizona and, indeed, the air about 10 cm off of the ground was on average cooler by 2C than the air at 1.5 meters up, but to my surprise the actual surface-of-the-ground temperature was warmer than both of these air temperatures. Ergo, this near-the-ground temperature inversion could not have been caused by the ground drawing heat from the bottom of the atmosphere since the ground temperature was about 5C warmer than the air only centimeters above it.

    Beyond that, the air temperature cooled at a faster rate than did the ground. What I postulate is that upper troposphere cooling is a 24 hour a day phenomenon and cool air from aloft is gravitating towards the earth 24/7. At night this cool dense air builds up at ground level because the sun is not feeding the ground enough thermal energy to reverse the temperature inversions that was caused by cool dense air descended to the earth from some higher, cooler altitude. Naturally such temperature inversions will be the largest when and where the sun is the weakest–at night, during the winter, at the poles.

    This also explains why cloudy nights are warmer than clear nights since clouds act a false “floor” and prevent this cool, dense, descending air from reaching the ground unimpeded. This is an actual “greenhouse effect” since the glass roof and walls of a greenhouses do the same thing; they keep cool air from aloft from replacing the warm air within the greenhouse.

    Carl

  8. wayne says:

    Carl Brehmer, that’s some very good investigating there. Way to go, but I’m not sure if your impression of upper air being the cause of the bottom 1 cm or so being so cold but maybe you might consider this.

    Have you ever looked very deeply into radiation cooling? That is one of the process they use to produce temperatures nearing absolute zero, Bose-Einstein condensates and such. It has everything to do with what is called stimulated emissions, the same used to create laser radiation but it can and does also occur right in the air of the room you are sitting in.

    See if this makes sense to you. I am going to speak of GHGs only that they have the ability to vibrate at about room absolute temperatures. When ever an excited GHG molecule is hit with a photon of the same frequency that excited it in the first place, that incoming photon causes the molecule to instantly release its energy as a matching photon and both of the photons continue in the same direction as that incoming photon causing the stimulated emission.

    Now look at the radiation coming from the surface of the Earth, it is all going upward to some degree, in all directions in a hemisphere. Even though radiation from the surface is rather net weak those up pointing photons if at a matching frequency of all GHGs (h2o & co2) will keep the molecules stripped from being excited sitting in the ground energy level. If a random photon of let’s say 15 µm is absorbed by a co2 molecule from above, it is a warming of one photon, right?, but that excitation is immediately stripped of that added energy by stimulation cooling from the gray body radiation from below and it is now back to where it was in the first place.

    This leaves the bottom centimeter of so very rarely in excited states so any warmth from anywhere above is immediately sent back upward by the stimulation. If photons from the surface get absorbed in that centimeter or so then the same thing happens to it also. The air right next to the surface stays as a mini cooler.

    Those stimulated dual photons will be absorbed on further upward in the atmosphere, let’s say within a few hundred meters due too the absorption length and there most radiation is basically the same and in all directions so this stimulated effect cancels in all directions, it becomes not directional upward but isotropic and all cancel buy symmetry.

    Did you know that at 15 µm there are 8.5 billion times more stimulated emissions than spontaneous emissions? Surprised me when I became aware. The equation to calculate this is simply γ^3/(2hc) with the wavelength (γ) in microns. If you look this up under the topic of Einstein coefficients or radiative transfers that equation will usually be stated as A21 = B21•2hυ^3/c^2 or A21/B21 = 2hυ^3/c^2, ‘υ’ being the photon’s frequency, the later giving the probabilistic ratio, but it does reduce down to the same given above for wavelength.

    If all radiation from the ground was parallel and always exactly zenith we would have a very, very weak infrared laser effect just near the surface. ;) This effect you never notice or cam measure of course for in normal diffuse radiation they are randomized on a photon by photon basis, but this does occur, it’s in the physics books though some of this explanation is from me reading between the lines.

    See if that doesn’t seem how this mysterious bottom one inch or so is colder than either the surface it lies against OR the air just above. Seems that way to me, but then, I am just becoming aware of such effects myself.

    If anyone else reading here knows this to be blatantly incorrect, please comment on it with some references, everyone wants to know exactly how our atmosphere operates right down to the last itty-bit.
    [typo fixed, million to billion --mod]

  9. tchannon says:

    Carl is correctly pointing out the ground cooling appears to be an assumption, no support was given.

    However, this is a conflict of measured information…

    Carl mentions North Arizona, and finding details which look interesting.

    Maybe Hans Jelbring has additional information about night conditions measuring in a desert region. Wonder how far that went?

    Looks like we are reaching back one year on the Talkshop.

    “Hans says:
    March 20, 2012 at 10:19 am (Edit)

    As far as can understand the expression “observed back radiation” means measured IR electromagnetic radiation at levels of +300 W/m^2. Here is a source showing that there is little scintific basis for such claims. The data set is from the Koorin expedition 1974 at Daly Waters, Australia.
    much real data was collected every hour during 30 days. Just to restrict the information to radiation data the following variables were measured. Global radiation (IR + light), Net radiation (IR + light), ground flux soil (at 25 mm depth), ground flux (probably at 100 mm depth). Here I will just recapulate global and net flux and the differenc between them for each hour during day 10. Similar values are found all the other days with little difference. All numbers in W/m^2.”

    { Plot and data follows on link }

    https://tallbloke.wordpress.com/2012/03/16/hans-jelbring-back-radiation-and-observational-meteorologial-evidence/#comment-20475

  10. tchannon says:

    Given the immediately above I would like to know more about ground/surface humidity since water phase transition might be involved leading to close surface detail processes.

    In broad terms I do not accept cold air sinking unless the air is cooled higher in the atmosphere and merely pooling at ground level. I point out this is similar to the effect at work topographically with frost hollows but is not general.

  11. donald penman says:

    It seems that vegetation has a large effect on air temperatures but air temperatures do seem to follow surface temperatures in general.I would think that weather patterns would also effect air temperatures and ground temperatures as well as there being no sunlight.
    http://www.agu.org/pubs/crossref/2011/2010JG001486.shtml
    http://journals.ametsoc.org/doi/full/10.1175/1520-0450(2000)039%3C1570:RBSTAA%3E2.0.CO%3B2

  12. Arfur Bryant says:

    Carl makes an interesting point. I would want to know the actual surface (ice/snow in this case?) temperature before making any assumptions about the type of cooling.

  13. tchannon says:

    Very much a case of need to know more, devil in the (missing) details.