Guest Post by Willis Eschenbach
Despite doing lots of research and investigations over the last few weeks, I’ve written little. Well, actually, I’ve published little, although I’ve written a lot. But I didn’t publish what I’d done, there was no wonder in it, no awe. So I tossed it all out and started “simply messing about”, as the Toad had it. For no apparent reason, I got to looking at the various methods for estimating the downwelling longwave radiation (DLR) based on surface conditions. DLR is the radiation emitted by the atmosphere which is directed downwards towards the earth. There’s a good summary of the various DLR estimation methods here.
In any case, I wanted to compare the estimated DLR to the DLR from the CERES satellite observations. I used the “Brunt” method, which calculates an “effective emissivity” from the vapor pressure. The vapor pressure in turn is calculated from the surface temperature. I subtracted the satellite observations from the Brunt estimate. Figure 1 shows the result.
Figure 1. Difference between the downwelling longwave radiation (DLR) as calculated by Brunt, and the downwelling longwave radiation dataset from the CERES satellite data.
I busted out laughing when I saw that graphic come up on the silver screen. I do my science visually, by painting the transformations and relationships in color. And in general, I have only the vaguest idea of what any given graphic will look like before it is displayed. So watching the graphics appear onscreen is like opening a line of scientific presents. Each one is unexpected, each one reveals new things.
This one was funny to me because it was such an excellent and detailed map of the desert and arid areas of the planet. From the Sahara to the Atacama Desert, the Gobi, the American Southwest, the Arabian Peninsula, the Namib Desert, it’s all laid out in precise detail. Heck, you can even see the green areas of Australia as a thin strip along the east and north coasts.
This is a curious result because the CERES satellite doesn’t measure water vapor … but what we have in Figure 1 is a map of water vapor. Over the desert areas we get less downwelling radiation than the estimate suggests, because water vapor is the main greenhouse gas. In the desert the air is so dry that more radiation escapes to space, and less is absorbed and radiated downwards (and upwards) by the atmosphere. It also shows the moistest areas of the planet (dark green and blue). These are in the equatorial tropical forests, where transpiration combines with evaporation. This leads to lots of water vapor, and a concomitant increase in DLR above what the estimate suggests.
This is the first time I’ve looked at the difference between a variable in the CERES dataset and an estimate of that variable. They say that all models are wrong, but some are useful. This model of downwelling longwave radiation is obviously wrong … but it’s useful because of exactly where and how much it is wrong.
Which leads to the final surprise for me, which was the size of the deviations from the expected DLR. From very dry regions to very wet regions is a range on the order of 100 W/m2 of downwelling LW radiation … I didn’t think it would be that big.
Anyhow, that’s the kind of thing I like to write about—the unexpected. For me, the adventure of science is never knowing which bush might be the one that hides the rabbit …
Regards to everyone,
w.
As Always: If you disagree with someone, please quote their exact words so we can all understand your objection.
A note on the Brunt Method: The Brunt method estimates the “effective emission” as a function of the form
a1 + a2 * sqrt( vapor_pressure )
Per the above citation, the canonical values for a1 and a2 are 0.51 and 0.066.
When I fitted the values, I got a1 and a2 as 0.65 and 0.029. I thought this might be a result of including the ocean. So I looked at just land, which gave a1 and a2 as 0.65 and 0.024. And looking at just the ocean I got 0.66 and 0.030. None of these are near the values given in the reference. However, they work quite well, and the canonical figures give much larger errors. Go figure.
I too am interested in the dataset you used. It seems to me that the poles should show up as more arid. I wonder if the long dark polar winters and midnight sun summers affect the data. Is an annual average or just several days near June 21 like in the paper you linked? — John M Reynolds
Note that the error is given as total DLR, not a percentage. The low temperatures at the poles means that DLR is quite lows there. Even so much of East Antarctica is “borderline desert”. It would be very interesting to see a map that shows percentage discrepancies rather than absolute figures.
“This one was funny to me because it was such an excellent and detailed map of the desert and arid areas of the planet.”
The yellow regions look more extensive than the actual desert regions. Reduced atmospheric water vapour in the horse latitudes is not solely dependent on dry land regions.
The yellow region matches the North American Deserts pretty well.
Using surface temperature to estimate absolute humidity of the atmosphere is just an approximation, and will of course be too humid in desert regions and too dry in the ITCZ, Amazonia, and the Congo basin. An interesting factoid about major deserts is that they are net radiative sinks, that is, they absorb less radiation from the sun than they lose to space in the infrared. They are part of the Earth’s radiative exhaust ports.
I don’t know if Kirchoff would agree with you. His stuff is a law and not a theory. High absorber , high emitter. Low absorber, low emitter. Based on wavelengths, of course. Broad spectrum readings and albedo are a bunch of crock. All the SB , planck theories were based on individual wavelengths or narrow bands of wavelengths. The earth is not a blackbody. It is covered in regions of non grey bodies.
If you choose to , you can turn your head to the side and squint your eyes and pretend the average of earth is a sort of grey body.
I hope I misunderstood your comment.
apparently you did misunderstand. The deserts absorb an average amount of sunlight, and (along with the overlying atmosphere) give off an average amount of IR to space. The latter is somewhat larger than the former. The difference is made up by atmospheric energy transport from other regions, which warms the desert airmass from subsidence-induced heating, driven by latent heat release in rain systems elsewhere. Not a controversial subject that I know of.
Roy Spencer said:
“The deserts absorb an average amount of sunlight, and (along with the overlying atmosphere) give off an average amount of IR to space. The latter is somewhat larger than the former. The difference is made up by atmospheric energy transport from other regions, which warms the desert airmass from subsidence-induced heating, driven by latent heat release in rain systems elsewhere. Not a controversial subject that I know of.”
SUBSIDENCE INDUCED HEATING
That is what makes the desert surfaces rise above the S-B temperature and NOT DLR which is why the deserts get hottest when they have least DLR.
The only point I disagree with Roy about is that he thinks that a non GHG atmosphere would become isothermal but it would not because uneven surface heating still causes density differentials in the horizontal plane so we would still see a similar air circulation pattern even if there were no GHGs at all.
Convective overturning warms the surface above S-B via adiabatic cooling on ascent and adiabatic warming on the descent and the radiation fluxes within the atmosphere are a consequence rather than a cause.
Alex, I do believe you have that backwards. Planck and S-B are based on broadband radiation following the curve that Planck figured out from Kirchoff’s work on black bodies and the relationship between wavelength and temperature… what we call a black body curve. (The good absorber, good emitter thing was already known, Kirchoff built on that and Stewart’s work.) Line emitters and absorbers do NOT follow those rules and therefore have extremely small emissivity numbers (CO2’s is 0.0017 at NTP.) That’s one of the larger failings of the AGW crowd is they treat line emitters as black bodies. Emissivity varies by material so deserts of soil or sand are going to have emissivities between 0.38 and 0.76 based on the materials they contain.
nielszoo March 28, 2015 at 7:14 am
I beg to differ. They use lambda in their equations. Cant type Lambda figure , but you know what I mean. They always included lambda.
Roy Spencer March 28, 2015 at 6:57 am
‘they are net radiative sinks’
your following sentence :
‘they absorb less radiation from the sun than they lose to space in the infrared’
I saw this as a contradiction.
I wasn’t contradicting the obvious situation of airflow from other regions.
nielszoo March 28, 2015 at 7:14 am
‘Line emitters and absorbers do NOT follow those rules and therefore have extremely small emissivity numbers (CO2’s is 0.0017 at NTP’.
A total contradiction within one sentence.
Kirchoff’s LAW has not been found wrong. That’s why its a LAW in physics. You don’t get to be a law if there is reasonable doubt like a theory.
Please point out to me where I can find information to corroborate the first part of your sentence.
Alex, I don’t think arguing with Roy is a good idea.
jorgekafkazar March 28, 2015 at 1:16 pm
I am not arguing with Dr Roy. Just seeking clarification. I think I was quite polite.
Roy Spencer said:
“An interesting factoid about major deserts is that they are net radiative sinks, that is, they absorb less radiation from the sun than they lose to space in the infrared. They are part of the Earth’s radiative exhaust ports.”
But the horse latitudes have less atmospheric water vapour, so they don’t absorb so much solar near infra-red, so regionally there would be higher than average surface irradiance. That’s why the deserts are there in the first place. I assumed you meant average solar radiation?
–An interesting factoid about major deserts is that they are net radiative sinks, that is, they absorb less radiation from the sun than they lose to space in the infrared. They are part of the Earth’s radiative exhaust ports.–
It is kind of interesting.
Are they exhaust ports? Or places where warmed air is expelled. Or a idea like a heat sink does not really work, not even radiate fins.
Anyhow opposite of exhaust ports are inlet ports, and that doesn’t help much other than bring to mind, tornadoes.
One could say deserts are the furthest extreme of a water world- or bodies of water are a contrast to deserts. And oceans seem more like heat sinks- at least in terms radiant energy from the Sun.
Generally I would tend to think of the poles as exhaust ports though inverted exhaust ports or inlets could be as descriptive. And poles get the spinning or vortex stuff.
Now are deserts air pumps/air fans? Do they blow in daylight and suck at night?
Anyways deserts are most like a world which didn’t have 70% of it’s surface being water.
It’s my general assumption that if add water to deserts one increase global temperature [though granted deserts are small area of the global]. Or I have long assumed that if large scale efforts were made to green the Sahara desert, the net result would be an increase in average temperature. Maybe that’s wrong. But in terms of exhaust ports how would greening of the Sahara
desert affect the exhaust port of the Sahara desert?
Or does it increase or decrease the exhaust of this exhaust port?
Deserts have the highest temperatures and the as good an optical path to space as anywhere, and since radiation is the only way off the planet they would probably have the highest W/m2 on the planet.
–Deserts have the highest temperatures and the as good an optical path to space as anywhere, and since radiation is the only way off the planet they would probably have the highest W/m2 on the planet.–
Deserts close to tropics would be better places to harvest solar energy.
One also has the “Horse latitudes or subtropical highs are subtropical latitudes between 30 and 35 degrees both north and south. This region, under a ridge of high pressure called the subtropical high, is an area which receives little precipitation and has variable winds mixed with calm.” -wiki
And I assume one has Horse latitudes condition even in middle of an ocean.
I also assume despite the large amount of solar energy that deserts absorb the smallest fraction of the incoming solar energy, in contrast an ocean absorbs the high fraction of the incoming solar energy.
I would think they absorb less, yes, but I think the bigger difference is that warm water moves.
“It’s my general assumption that if add water to deserts one increase global temperature..”
It will cool the desert, so how will that increase global temperature?
Possibly daily min temp would go up more than max temps go down, so the average would be higher.
Most continental interiors cool with increased rainfall, typically in a cold AMO mode, and during La Nina episodes.
—micro6500
March 28, 2015 at 3:17 pm
Possibly daily min temp would go up more than max temps go down, so the average would be higher.–
Yes it mostly about raising the average min temp.
But actually that is also true as far as theory of Earth’s Greenhouse Effect.
Or all that the greenhouse effect can possibly do is raise the average min lowest temp. And the only way one can imagine the Earth greenhouse effect making it warmer is by increasing the min temperature so that in the morning
of a day one starting from a warmer temperature, and thereby requiring less heating to get to highest daytime temperature. Or said differently if one has weather in summer which causes cool temperature, it generally takes a couple days to warm back up again.
Or the greenhouse effect would need to prevent cooler nights in order to give you warmer days.
But it should noted, that I don’t believe greenhouse gas are adding +33 C to Earth average temperature, so perhaps a believer in the theory would like to correct me, as far as the correct interpretation of their faith.
And far as know the only thing which could raise max air temperature [other than starting with a warmer min temperature] would be wind blowing across a heated ground surface bring warming air to another area. Or UHI effect or lower elevation.
Now I wondering whether anyone found that golf course should add to UHI effect [in terms of increasing night time lows] but a quick search didn’t find this, instead this article said golf courses [regions of greenery] lower UHI effects:
http://transitiontownpayson.net/2014/04/06/adaptation-volume-10-battling-the-urban-heat-island-effect/
And tend to agree that a park will not warm as much as asphalt parking lot.
But also a sandy desert is somewhat like a asphalt parking lot, and likewise
if replace a desert with greenery and waterworks it should also have cooling effect, And the large area of Sahara desert might adding considerable warmth
to a larger region. So therefore my doubt about it.
But just the Sahara desert region itself should be warmer due to it having warmer nights.
I can tell you for certain that when you look at surface station data, the annual average of yesterday’ s rising temps to last night’s falling temps, if you round to 1 decimal they are both 0.0F, if you go out to 3 (?) Falling temps are slightly larger than rising temps. Now this confused me for a long time, until I realized the excess heat was coming from air heated in the tropics. ren’s water vapor map shows large amounts of water spinning out of the tropics.
That makes sense. Sand and rocks reflect energy as well as absorbs energy only to released that energy later . When plant life absorbs energy some of it converted and not released.
Welcome back. Whether or not I always understand what you’re writing (my limitations – not yours), your writing style is always a joy to read.
“SOFIA is based on a Boeing 747SP wide-body aircraft that has been modified to include a large door in the aft fuselage that can be opened in flight to allow a 2.5 meter diameter reflecting telescope access to the sky. This telescope is designed for infrared astronomy observations in the stratosphere at altitudes of about 41,000 feet (12 km). SOFIA’s flight capability allows it to rise above almost all of the water vapor in the Earth’s atmosphere, which blocks some infrared wavelengths from reaching the ground. At the aircraft’s cruising altitude, 85% of the full infrared range will be available.”
The deserts occur where the dry Hadley cell downwelling touches down. Just as the tropical rain forests occur where the wet Hadley cell upwelling begins.
You’re looking at the effects of atmospheric circulation: the water vapor distribution is a consequence of that circulation. Your satellite imagery probably doesn’t show much of the polar areas, but they are deserts, too, because of downwelling of dry air. It should show the temperate rainforest regions (US NW and BC) where there is also an upwelling of wet air.
One of the methods is right (and the other is wrong) or it might be a blend of the two.
Nevertheless, DLR is a process that underlies the very nature of global warming theory. It is one of its key foundations. If they are doing DLR wrong or the water vapor component of it wrong, then there is a big problem.
From what I’ve read, DLR is a theory promoted by some. It seems to be promoted by warmists because it’s convenient. DLR comes back to downwelling radiation. CO2 heating the surface etc. If you subscribe to the idea that the atmosphere heats the earth then DLR is a ‘thing’. If you don’t subscribe to that thinking, then DLR is just a distraction from the truth.
I think of DLR as coming from all of the air around you. DLR could be coming from water vapor or CO2 or solid surfaces which are just metres away from you. It is being emitted side-ways, up and down and all around by every excited molecule in your/or the instruments vicinity. It is the very nature of a gas and there are billions of photons of LW hitting you every second from everything. If you are in a room right now, there are billions of photons being emitted by every solid surface in that room. It still bugs me than noone will say O2 and N2 also emit blackbody radiation but that is for another thread and another day.
That sounds like kinetic energy rather than radiation. The photons you are referring to are incredibly low in energy. I am not denying that they are there. Most molecules lose their “absorbed’ energy by impact with other molecules. What would be left over for radiation purposes would be negligible. I suggest doing some planck calculations. You will find that the number of photons increases, the lower down the scale you go. Essentially more photons but with a subsequent lower energy per photon until you can practically walk on a sea of photons at 3 K. The energy of a visible light photon is millions time stronger than a photon emitted at 14 micron
I agree that photons from GHG will strike the earth, But I wouldn’t write mother about it.
O2 and N2 do emit radiation, But only in the wavelengths that they absorb (Kirchoffs Law). They don’t emit broad spectrum.
I’ve been measuring Tsky with a IR thermometer, most of the winter it was below ~-60F, the really cold days and nights it was near -80F.
But even this cold, when rel humidity gets up over 80% cooling slows down.
And at the same time if you measure surface vegetation it’s colder than air temp, while concrete and dirt at warmer than air temps after a night of cooling at 10F.
micro6500 March 28, 2015 at 7:38 am
I’m into instrumentation. Just be careful how you use this IR thermometer. You could take your eye out. Sorry, just kidding. Even though they say that they operate over a certain range , you have to be careful.
If you buy one of those things its like signing a contract with the devil. You really have to look closely at what the specific thermometer is designed for. Using it outside that range can give you strange readings.
Ir thermometers are designed for specific ranges. Hi temp, cryogenic or ‘General purpose’. They are purpose built for specific applications.
Point it at the next full moon and let us know what the temperature is. Just for fun
Think of it as a 8-14u signal strength meter calibrated to a blackbody. So the moon will measure the same as the rest of the sky, except in the general direction of the Sun.
But only because there isn’t a lot of 8-14u photons, which is sort of the point.
The caveat is you have to add the Co2 flux to the BBQ flux
Well the BBQ has a fine flux, but you have to add the Co2 flux to the blackbody flux to get the correct total flux.
Alex,
the number of photons is the intensity, the energy level of the photon is the frequency, so yes lower frequencies have less energy, but that does not mean there must be more of them.
eg moonlight has few photons at visible wavelengths and sunlight has many photons at visible wavelength.
warmer surfaces will have more IR emission than cooler surfaces.
the lower atmosphere in general has a lot of water vapour , so yes the dominant transfer of heat is kinetic and convection until at the top of the troposphere there is so little water vapour that radiation becomes the primary form of energy transfer. to add an extra absorber in the mix means that the surface at first loses more heat to the atmosphere, but the capacity of the atmosphere has increased, so once capacity is reached (not completely), there will be a warmer atmosphere than before. the surface can no longer lose as much warmth as it did before.
the way the ipcc presented this was that the top of the troposphere should increase in height. it means that because the surface warmed and evaporation would increase, they predicted that the water vapour levels would increase at the top of the troposphere and due to the fact that the air is very cold there (concentrations low) there should be a very visible sign of extra warming (log up there to little on the surface).
so, what happened? it did not warm, water vapour did not increase there. this means there is NO water vapour feedback in the radiative zone, only in the lower troposphere where there is now a bit more water vapour. warmer? yes, but how much warmer?
well the models that the ipcc use (using those same calculations that are obviously not correct) place the feedback from water vapour at a very large percentage. the last 18 years have shown that both the upper and lower troposphere have not increased in temperature, yet the specific water vapour has increased(by as small a fraction as before). this really is proof that the feedback expected from water vapour should be in the form of rain/clouds and negative in nature, not positive. and co2, well it is just being drowned out by water vapour/clouds/whatever else.
Mobihci,
This very close to what I think the data we have shows, Co2 might flavor the mix, but without water there is no soup.
Why is it that we can see things if photons are criss crossing and bouncing all over the place? Is it only LWR that does this? Even then, we can see infra red images with the right optical gear. When I read a book, the light from ‘abc’ doesn’t interfere with that of ‘def’ by criss crossing or the light from distant stars.
The driest places on earth are the polar deserts.
“In the desert the air is so dry that more radiation escapes to space, and less is absorbed and radiated downwards (and upwards) by the atmosphere.”
It would seem then that the major (and perhaps only) temperature moderator/sink on Earth is water/water vapour. I understand what you are saying but is there not also an effect on temperature as a consequence of the ground being open and dry (again lack of moisture) and that sandy deserts are poor heat reservoirs? I read that sand is a good heat sink and will release heat slowly in which case why do sandy desert areas lose heat at night so rapidly? Is it really just the open dry skies allowing radiation out or is it not compounded by the fact that the surface reservoir of heat is not that much or deep? When I’m at the beach after sunset it is the sand that seems to cool off much quicker that surrounding roads and walls.
” I read that sand is a good heat sink and will release heat slowly in which case why do sandy desert areas lose heat at night so rapidly?”
Years ago I used to do some stargazing as night in the desert. The top of the sand would cool rapidly. I would dig a shallow trench in the sand to lie in. The sand a few inches down was always warmer. I’ve also noted nearby rocks splitting off a shard from the surface with a sharp crack. On checking I found that the inner volume of the rock was much warmer than the surface. The splitting off was due to shrinkage. An example of how heat is stored in the desert rocks and doesn’t take long to warm up again during the next days sunshine.
Product shows the Outgoing Longwave Radiation (OLR) from the Advanced Very High Resolution Radiometer (AVHRR) and High Resolution Infrared Sounder (HIRS). The AVHRR and HIRS OLR products are divided into day and night (ascending and descending) products.
Monthly Mean
— Day
http://www.ospo.noaa.gov/data/atmosphere/radbud/gd19_prd.gif
Monthly Mean
— Night
http://www.ospo.noaa.gov/data/atmosphere/radbud/gn19_prd.gif
Kind of annoying they shifted the scales between day and night. Gives the impression more OLR at night, which is not the case.
Good observation on your part
Thanks, other than that those are excellent graphics.
Please still see steam in the tropopause.
http://www.ospo.noaa.gov/data/mirs/mirs_images/n19_wv_200mb_des.png
Product shows the average solar radiation absorbed (W/m2) in the earth-atmosphere system. It is derived from AVHRR Channels 1 and 2. The mean is displayed on a one degree equal area map on a seasonal basis. This product is also referred to as Shortwave Absorbed Radiation (SWAR). Absorbed solar radiation is the difference between the incoming solar radiation at the top of the atmosphere and the outgoing reflected flux at the top of the atmosphere.
Monthly Mean:
http://www.ospo.noaa.gov/data/atmosphere/radbud/swar19_prd.gif
Product shows the incoming solar radiation at the top of the atmosphere. It is derived from the AVHRR instrument. The available solar energy only varies with the solar zenith angle.
Monthly Mean, 2/2015
Willis … you’ve struck a possible gold mine!!
Given that you have a map here of water vapor and DLR, you should be able to calculate:
1) a curve of the contribution of water vapor and CO2 [representative of all other GHGs] on DLR in a real time scenario, vs a model.
2) an extrapolation of the true impact of CO2 on DLR in the atmosphere with water vapor set to ZERO.
3) the real contribution of water vapor feedback in the atmosphere according to lat/long., thus putting to rest the assumptions about water vapor in the GCMs.
DUDE … truly, you could define the Greenhouse Effect across the globe more accurrately than any model, and from that actually approach a true attribution of Natural Forcings, Anthropogenic Forcings, as well as Feedback magnitude as data sets, and compare those to the temperature trends!! You could even do this according to Lat/Long, teasing out a differential effect of the Green House Effect at different places on the earth.
You could be on the verge of blowing the “quantification” question regarding Global Warming wide open!!
Just Sayin’
BTW … just contact Anthony for name and info, so you can put my name on the paper!! 🙂
Am i understanding you? Willis could use satellite data somehow to see if there is a change in the daily/seasonal timing of the overturning of heat/moisture from the tropics to the desert areas? If there is a change over X years, and if follows CO2 increases, one has hard data as to the effect of the added CO2?
not
It would be a calculated proxy no matter how you use it, and have no forward predictive use in terms of future increased CO2/water vapor amplification. You would only have scenarios if I am getting this method correctly. Given natural variability, any scenario might be swamped in noise.
However, to narrow/refine Dr. Deanster’s comment (and please Dr. Deanster tell me if I have this wrong) if the data used in this proxy exists for the past, you might also add to it by calculating the affects of just the increasing anthropogenic portion of CO2 along with the calculated proposed increase in water vapor, then by comparison with Willis’ work, would justify AGW or not. IE you would have to subtract the amount of CO2 increase that is a natural consequence of “greening” during a warming cycle, leaving only the anthropogenic portion related to fossil fuel use, in order to see whether or not anthropogenic fossil fuel CO2 emission derived water vapor increased along with DLR. Because this part is a calculation, not an observation, you would only be able to suggest the validity or not of the AGW theory. By mind experiment, the pause could very well be explained in terms of whether or not AGW was involved at all.
I still haven’t consumed the required amount of coffee after a Friday night so I could be just confused.
Pamela … essentially what I’m saying is … CO2 is estimated to be a well mixed atmospheric gas, and as such, its DLR effect should be constant within a definable parameter based on long/lat data. Desert DLR should be somewhat representative of the DLR of CO2 [and other non water vapor GHGs] with minimal contribution from water vapor … while the Tropics should be representative of the DLR of CO2 and higher water vapor. … and points in between give us middle values. Given that CO2 is constant [a well mixed gas], we should be able to fit a curve to the DLR data and draw it up on a curve relative to water vapor content. Where the line crosses the Y axis, will be representative of the raw CO2 signal at ZERO water vapor. The shape of the curve will give us a picture of how water vapor contributes to DLR with rising concentrations.
THEN … as you say … after determining the real value of DLR contribution from CO2 in the atmosphere, we can then calculate the contribution from the anthropogenic contribution. … not in terms of ppm, but in terms of DLR!
I’m just thinking out loud here.
I’m definitely not sold on the CAGW or even the AGW theories .. I”m not sure CO2 or the greenhouse gas has anything to do with “rising temperature trends” .. and frankly, given the testimony of Dr. Collins at the APS debate, and confirmed by the panel … there is no first principle evidence to illustrate just WHAT caused the increase in temp. As such, I don’t think anyone knows SQUAT about climate, outside of a lot of unproven theories and hypotheses…. and mathmatical equations on radiation.
The Brunt method comes in for corrections based on surface radiation, which could very well be influenced by lots of factors, but, if I’m not mistaken, must have some impact on the DLR, as the surface radiation is the source of the LR. It seems to me Willis comparison hints at this.
Granted, before you slap me down, know that I do NOT view Climate from any conventional perspective. What people claim is “known” is obviously not! It’s just accepted.
Wasn’t even considering a slap down. I think the mind experiment is very interesting. These various proxies of intrinsic energy absorption and re-radiation is fascinating and like you, I think Willis is on to something here.
There seems to be an odd hemispheric bias in the data. In the northern hemisphere the yellow areas are indeed true desert, while in the southern hemisphere much of the yellow areas are “only” steppe/savannah, e. g. much of Patagonia, Eastern Namibia, Botswana, Zimbabwe and the Murray/Darling basin of Australia.
In the northern hemisphere the match is indeed impressive, it even “catches” the small Turkana/Didi Galgala desert of NW Kenya that most people have never even heard of.
It is also the case that those dry areas with most DLR getting to space directly from the surface are beneath columns of adiabatically warming descending air within semi-permanent high pressure cells.
That perfectly illustrates my contentions that:
i) The ‘extra’ warmth at the surface (above S-B) is caused not by downward radiation but the reconversion of PE to KE as descending air compresses beneath the increasing weight of the atmosphere above as it descends. If that extra surface warmth were caused by downward radiation from GHGs then the colours would be reversed and the warmest surfaces would be beneath the more humid regions (more GHGs).
ii) The kinetic energy available to be extracted at the surface from descending adiabatically warming air is more readily lost directly to space from those desert surfaces due to the lack of GHGs above (dry air) and so as per my previous comments here and elsewhere it is the adiabatic convective overturning cycle that varies so as to readjust the energy escaping to space directly from the surface as compared to that escaping to space from within the atmosphere.
Willis has kindly proved my case with this article and for readers who still don’t understand what I am saying I can only recommend some meteorology studies.
The truth is that GHGs merely reapportion radiation escaping to space between that leaving from the surface and that leaving from within the atmosphere and the mechanism effecting that reapportionment is the adiabatic convective overturning cycle. Both before and after any such reapportionment radiation out to space matches radiation in from space and surface temperatures remain the same despite small variations about the long term average which is set by atmospheric mass and density.
GHGs thus have zero effect on surface temperatures but would have a miniscule effect on atmospheric circulation and the positioning of the climate zones but any such effect is magnitudes smaller than similar effects from solar and oceanic variations.
I sympathise Stephen
Most people don’t realise that kinetic energy transfers more than radiation. They think that radiation is all powerful (because radiation from some substances can kill you). They don’t realise we live in an ocean of radiation and we need highly specialised equipment to find it. I can find kinetic energy effects with a glass thermometer, but that’s too boring
this kind of argument is a huge reason why “skeptics” lack credibility. The idea that “because ACC isn’t real, the mechanisms that they use to describe it must also not be real.” This is what most people in the den**r crowd latch onto, and a good reason for ridicule.
The greenhouse effect is well documented and well understood. Trying to redefine it as a “redistribution” of energy is absolutely false.
Is it because the mis-named “greenhouse” effect conjures up wrong understandings about the real “outgoing-partially-reabsorbed-then-reradiated-in-all-directions-including-down”, Earth-warming longwave infrared radiation issue? A real greenhouse warms the inside by a different process. I prefer to say it this way: The warming effect of re-radiated LWIR.
A real greenhouse roof allows solar radiation in through the transparent roof and subsiding warming dry air mimics that effect to dissipate clouds and allow more solar energy to reach the surface.
A real greenhouse roofs prevents convection and subsiding warming dry air mimics that effect by preventing warmed surface air from convecting upwards as fast as it otherwise would have done.
The so called greenhouse effect is correctly and accurately so described but it is to do with atmospheric mass and not radiation.
The observed radiative fluxes are then a consequence of the variable vertical temperature profile along the lapse rate slope and not a cause of anything.
There is no radiative greenhouse effect but there is a mass induced greenhouse effect.
+1
This is why over a few days clear sky day time temps can change 20-30F, cause it’s not solar or Co2.
And as best I can tell it’s the water content that matters.
Gee we skeptics make up only 3%, everybody including elected government, its enforcers and useful idiots are castigating, investigating, insulting, and even threatening bodily harm, imprisonment, etc. and one of their numbers (something else) tells us we lack credibility! I have to admit, even I’m surprised that the handful of serious skeptics (a proportion of the 3% ARE unthinking contrarians and politically motivated who not only don’t contribute, but detract from the skeptic’s efforts and give the masses ugly labels to stick on all skeptics) have struck so much fear into the hearts of the enormous throngs of the settled science folks who will be turning their lights out for an hour tonight and want to turn them out for all of humanity for all time.
“The lady doth protest too much, methinks”
Don’t you think?
That’s funny, one comment that illicits a number of responses and I’m the one the protests to much? Seems more like I struck a nerve.
Yeah, but (someone else) you clones out number us over 30 to one! I call that bullying although I have a principle – I never engage in a battle of wits with unarmed opponents. Old joke: There we were 2 against 100, boy did we ever kick the spit out of those 2 guys!
Someone else,
How exactly is the ‘greenhouse effect’ well documented? What precisely is it that is well documented? The fact that CO2 and H2O absorb IR at certain wavelengths? Or the assumption that this property somehow warms the surface of the Earth?
The sun provides three basic types of solar energy waves: ultraviolet (UV) waves, visible light waves, and shortwave infrared light waves. Each of these light waves has a relatively short wavelength compared to longwave infrared, and will pass easily through most types of relatively clear greenhouse coverings. Once inside the greenhouse, the waves are absorbed by plants and the ground and are used for photosynthesis as well as generally warming things up, which also produces humidity through evaporation. That energy is then transformed into thermal, or heat energy. Moist air can hold more heat than dry air and a greenhouse is notorious for producing humid air. Because thermal energy has a much longer wavelength than light waves, it cannot pass back through the greenhouse covering, and remains trapped inside. Venting is used as needed to relieve built up heat. You can even buy motorized openers that include an internal thermostat you can set so you don’t have to vent manually. The combination of trapped longwave thermal energy and humidity requires the use of fans and/or venting.
The Earth is not like a greenhouse in that the Earth leaks thermal energy far more readily and far more inconsistently compared to a real greenhouse, as can be seen when measuring outgoing longwave radiation. It is far more complicated than that of a greenhouse and I think the use of that term confuses many skeptics.
Pamela,
None of that discredits the similarities that I pointed out between the way a greenhouse works and the effect of subsidence warmed descending air (half the atmosphere at any given moment).
As for humidity that comes from the ground and vegetation and builds up when convection is restrained whether inside a greenhouse or beneath a descending column of air.
I know I have it right from long established meteorological principles.
“Each of these light waves has a relatively short wavelength compared to longwave infrared, and will pass easily through most types of relatively clear greenhouse coverings.”
But not water vapour, it has considerable absorption bands in the solar near infra-red.
“But not water vapour, it has considerable absorption bands in the solar near infra-red.”
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yes indeed. I forget the amount of TSI water vapor, clear sky absorbs, but it prevents a great deal of energy from even reaching the surface. I am not certain the residence time of this energy, failing to reach the surface, including the oceans, is properly considered.
“I am not certain the residence time of this energy, failing to reach the surface, including the oceans, is properly considered.”
The average probably is. But the distribution is most likely being overlooked. In the horse latitudes there would more than average solar NIR warming the oceans, because of less water vapour.
Let’s not forget about other forcings. I live in central North Carolina and wind direction means a whole lot about temperatures and air masses regardless of season.
A northeast wind brings air from the North Atlantic. North and northwest winds come in from central Canada. West are maritime all the way from the Pacific. Southwest are generally dry from Texas and beyond. South is from the Gulf of Mexico and Southeast is off the Gulf Stream.
Depending on the prevailing pattern we can be tropical-like, polar-like or desert-like and at our latitude of 35N and the season, it can switch fairly rapidly from one to the other.
An instructive paper (as usual) from Willis, coupled with instructive discussion. This is what WUWT is all about. Thanks everyone!
+1
+1 from another (simi?) old’un
Thanks, Willis. It is fun to read you messing about.
And yes, of course, water vapor is the most important atmospheric content, weather/climate wise. It is amazing to watch WV in the GOES pictures.
Another way to find the deserts is to map the diurnal temperature range. Berkley Earth used to have a map, but the link appears broken. Here’s another link:
http://www.esapubs.org/archive//ecol/E093/041/AppDImages/FigD1.jpg
Not very good at all. It turns large areas with continental climate into desert (e. g. Siberia around lake Baikal, parts of Canada). It also misses one of the world’s most extreme deserts Rub al’Khali because of the moderating effect of the Indian Ocean. Incidentally I know from personal experience of the area that the effect does not extend nearly as far inland as on the map, presumably this due to “smearing” of coastal weather station and the absence of inland stations.
Willis,
Since you say “based on surface conditions” I see two issues that cripple the Brunt model. First, in wet atmosphere there is a continuum spectrum from water vapor dimer, which has little effect in dry atmosphere; so, a better model would have two sets of constants, a1 and a2, or parameters dependent on vapor pressure. The second issue is that infra-red emission is a function of local temperature (if local thermodynamic equilibrium is a reasonable model) and so a better model would have to include lapse rate. I’ll bet one could construct a greatly improved model not much more complicated than the Brunt model. I have little familiarity with the literature here, so what are other models you might have considered?
The other side of the DLW radiation is here [click on ‘Global Temperatures’ on the left sidebar, then click on ‘Outgoing longwave radiation Global’].
They have to balance, or the planet will tend to either warm or cool.
Thanks Willis – very good evidence disproving the Brunt method.
Your results are very similar to Direct Normal Irradiance (DNI) used to identify solar CSP locations.
See the free DNI maps by SolarGIS. e.g. Global DNI
From the DNI global map it looks like we only need to get rid of China and global warming is solved !
According to that map Takla Makan, one of the World’s driest deserts has a lower DNI than Labrador. Must be due to the dust storms for which Takla Makan is notorious. Even so it’s odd.
tty Most SW USA appears to have higher DNI than the Sahara – with some interesting pros/cons to put it politely.
That story is similar to Bullwinkle in that it is rife with political/social commentary of the day.
Willis, something is precise in the combination of errors of the two methods. Note even the tiny desert on the South Island of New Zealand. Otago is a dry area in the middle of the island. During the 1800s gold rush days they cut runnels in the rock and dug ditches to bring water into the interior for gold sluicing.
http://www.naturespic.com/i/32571XA00_w.jpg
Ah, yes, Christopher, it was Ratty … teach me to trust my memory rather than go to the source …
w.
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