Guest Post by Willis Eschenbach
I took another ramble through the Tropical Rainfall Measurement Mission (TRMM) satellite-measured rainfall data. Figure 1 shows a Pacific-centered and an Atlantic-centered view of the average rainfall from the end of 1997 to the start of 2015 as measured by the TRMM satellite.
There’s lots of interesting stuff in those two graphs. I was surprised by how much of the planet in general, and the ocean in particular, are bright red, meaning they get less than half a meter (20″) of rain per year.
I was also intrigued by how narrowly the rainfall is concentrated at the average Inter-Tropical Convergence Zone (ITCZ). The ITCZ is where the two great global hemispheres of the atmospheric circulation meet near the Equator. In the Pacific and Atlantic on average the ITCZ is just above the Equator and in the Indian Ocean, it’s just below the Equator. However, that’s just on average. Sometimes in the Pacific, the ITCZ is below the Equator. You can see kind of a mirror image as a light orange horizontal area just below the Equator.
Here’s an idealized view of the global circulation. On the left-hand edge of the globe, I’ve drawn a cross section through the atmosphere, showing the circulation of the great atmospheric cells.
The ITCZ is shown in cross-section at the left edge of the globe in Figure 2. You can see the general tropical circulation. Surface air in both hemispheres moves towards the Equator. It is warmed there and rises. This thermal circulation is greatly sped up by air driven vertically at high rates of speed through the tall thunderstorm towers. These thunderstorms form all along the ITCZ. These thunderstorms provide much of the mechanical energy that drives the atmospheric circulation of the Hadley cells.
With all of that as prologue, here’s what I looked at. I got to thinking, was there a trend in the rainfall? Is it getting wetter or drier? So I looked at that using the TRMM data. Figure 3 shows the annual change in rainfall, in millimeters per year, on a 1° latitude by 1° longitude basis.
I note that the increase in rain is greater on the ocean vs land, is greatest at the ITCZ, and is generally greater in the tropics.
Why is this overall trend in rainfall of interest? It gives us a way to calculate how much this cools the surface. Remember the old saying, what comes down must go up … or perhaps it’s the other way around, same thing. If it rains an extra millimeter of water, somewhere it must have evaporated an extra millimeter of water.
And in the same way that our bodies are cooled by evaporation, the surface of the planet is also cooled by evaporation.
Now, we note above that on average, the increase is 1.33 millimeters of water per year. Metric is nice because volume and size are related. Here’s a great example.
One millimeter of rain falling on one square meter of the surface is one liter of water which is one kilo of water. Nice, huh?
So the extra 1.33 millimeters of rain per year is equal to 1.33 extra liters of water evaporated per square meter of surface area.
Next, how much energy does it take to evaporate that extra 1.33 liters of water per square meter so it can come down as rain? The calculations are in the endnotes. It turns out that this 1.33 extra liters per year represents an additional cooling of a tenth of a watt per square meter (0.10 W/m2).
And how does this compare to the warming from increased longwave radiation due to the additional CO2? Well, again, the calculations are in the endnotes. The answer is, per the IPCC calculations, CO2 alone over the period gave a yearly increase in downwelling radiation of ~ 0.03 W/m2. Generally, they double that number to allow for other greenhouse gases (GHGs), so for purposes of discussion, we’ll call it 0.06 W/m2 per year.
So over the period of this record, we have increased evaporative cooling of 0.10 W/m2 per year, and we have increased radiative warming from GHGs of 0.06 W/m2 per year.
Which means that over that period and that area at least, the calculated increase in warming radiation from GHGs was more than counterbalanced by the observed increase in surface cooling from increased evaporation.
Regards to all,
As usual: please quote the exact words you are discussing so we can all understand exactly what and who you are replying to.
Finally, note that this calculation is only evaporative cooling. There are other cooling mechanisms at work that are related to rainstorms. These include:
• Increased cloud albedo reflecting hundreds of watts/square meter of sunshine back to space
• Moving surface air to the upper troposphere where it is above most GHGs and freer to cool to space.
• Increased ocean surface albedo from whitecaps, foam, and spume.
• Cold rain falling from a layer of the troposphere that is much cooler than the surface.
• Rain re-evaporating as it falls to cool the atmosphere
• Cold wind entrained by the rain blowing outwards at surface level to cool surrounding areas
• Dry descending air between rain cells and thunderstorms allowing increased longwave radiation to space.
Between all of these, they form a very strong temperature regulating mechanism that prevents overheating of the planet.
Calculation of energy required to evaporate 1.33 liters of water.
#latent heat evaporation joules/kg @ salinity 35 psu, temperature 24°C
> latevap = gsw_latentheat_evap_t( 35, 24 ) ; latevap
# joules/yr/m2 required to evaporate 1.33 liters/yr/m2
> evapj = latevap * 1.33 ; evapj
# convert joules/yr/m2 to W/m2
> evapwm2 = evapj / secsperyear ; evapwm2
Note: the exact answer varies dependent on seawater temperature, salinity, and density. These only make a difference of a couple percent (say 0.1043 vs 0.1028941). I’ve used average values.
Calculation of downwelling radiation change from CO2 increase.
#starting CO2 ppmv Dec 1997
> thestart = as.double( coshort ) ; thestart
#ending CO2 ppmv Mar 2015
> theend = as.double( last( coshort )) ; theend
# longwave increase, W/m2 per year over 17 years 4 months
> 3.7 * log( theend / thestart, 2)/17.33
Perhaps Mother Nature has indeed turned down the thermostat to end a 200 year warming period!
Thanks for this interesting qualitative and quantitative insight! You never stop learning!
Indeed. Very simple and clear. It looks like Willis has found Trenberth’s “missing heat”.
I guess N. Africa will be glad of the extra 6mm/y. BTW what do the colour bands represent, is that green band 0-6mm/y or 3-9mm/y ?
It would be interesting if the same kind of analysis could be done for CMIP models. Do they get anyway close to displaying this kind of pattern, even in the most general terms?
Willis: Bravo. Clear, concise, well illustrated, and quite convincing. The planet equilibrates without human intervention.
It’s basic physics. At the skin interface between air and water or ice the, air will be saturated (100% relative humidity, air temperature equals dew or frost point), Evaporation is an endothermic process so the skin surface temperature will be at or near the dew point temperature. So the skin surface temperature is being controlled by the amount of moisture in the air, Not CO2. Check it out using NOAA’s CEOP derived parameter equations and the hourly average met and CO2 data at BRW, MLO, SMO, and SPO.
The other interesting feature is that the Pacific ITCZ appears to be increasing in it’s stable location over the time period.
The strong band of blue increased precipitation just north of the equator, is mirrored by an orange band of decreased precipitation just south of the equator (starting in the middle of the Pacific and heading eastwards).
I was expecting to see a symmetrical change on either side of the equator. An increase north of the equator matched by a decrease south of the equator surprised me. I wonder if anyone has an explanation for that?
The extra low level, heightwise, CO2 from the highly, heavily populated, highly industrialised SH? 😉
You don’t say why you were expecting that but the “atmospheric” equator is the ITCZ. You will see in fig.3 that the drying zone south of ITCZ is more diffuse yet lesser in magnitude than the drying zone to the north.
There may be an explanation for that difference is geometric symmetry of insolation centred on the equator.
A look at how the position of the ITCZ changes over this period may enlighten us about the origins of the “polar see-saw” and why , until 2012 the Arctic sea ice was retreating while the Antarctic was retreating. That seem to be reversing in the last few years.
“A look at how the position of the ITCZ changes over this period may enlighten us about the origins of the “polar see-saw” and why , until 2012 the Arctic sea ice was retreating while the Antarctic was retreating. That seem to be reversing in the last few years.”
Arctic sea ice was retreating while the Antarctic was retreating. –> Arctic sea ice was retreating while the Antarctic was growing:
Interesting post, as always, Willis! Even more so for me because, coincidentally, I was just discussing with a friend a few hours ago how my swimming pool is kept cool due to evaporation! The world has a very well regulated thermostat and water is that thermostat! Cheers!
I just like the word “spume”.
Oh, and another proof that climate modelers are full of beans.
I like that too.
Thank you Willis.
If there is an increase in evaporation/rainfall does that mean there is a corresponding increase in water vapor? And therefore an increase in the greenhouse effect of that gas?
Not necessarily. It depends on the speed of the hydrological cycle. If this is unchanged, yes there is an increase in water vapor.
But also note that an increase in water vapor necessarily means a flatter lapse rate and a tropical “hot-spot” in the upper troposphere. Which isn’t happening, suggesting that the hydrological cycle has indeed speeded up.
Yup, exactly what was predicted by Dr. William Gray.
tty, can you give your comments on the AMSU-data that Roy Spencer presents on his site, in his newest post. It looks like a hot spot there, what do you think about this? Why does the AMSU show this while AIRS is not?
Sorry, I mean the other way around. It looks like a hot spot in AIRS but not in AMSU.
Theoretically there should be no increase in water vapor. Adding heat to a closed circuit Rankine Cycle results in an acceleration in the cycle rate with no increase in working fluid mass involved. The Hydro cycle being in effect a Rankine cycle.
Interesting work and a nice comparison to IPCC also.
It gives perspective on the eventual “admission of model shortcomings” by IPCC in a few decades, or generations if following in the Vatican timescale of exoneration and admission.
Surely in the atmosphere the calculation is reversed. There is an additional 0.10 W/m^2 of heating from
the condensation of the water vapour plus 0.06 W/m^2 of heating from the additional green house effect
of the CO2 making an extra 0.16 W/m^2 of heat entering the atmosphere.
I was also wondering about the heat liberated during condensation….for the precip to fall again. Although perhaps this thought experiment is only considering processes that take place at or near the surface (?)
Condensation heat is liberated into the atmosphere at high altitudes where it is more readily radiated into space…actually assisted by CO2.
What Doc said …
It is not radiated into space. If it was then there wouldn’t be a radiative imbalance
at the top of the atmosphere. But as you pointed out there is a radiative imbalance of
0.06 W/m^2 and hence the earth is warming. It is this additional energy that then gets
circulated throughout the atmosphere by evaporation and condensation.
Not all of it, but most of it is radiated into space.
Is some of that heat/energy transferred to the nearby air molecules via conduction?
There must be a formula that tells how much of the energy liberated during condensation goes to conduction, radiation and convection/advection.
At the tropopause the ice crystals in the cirrus clouds grow dendritically so thus are losing energy by radiation into space.
At that temperature (approx -50C) it is a reverse sublimation process, so the change in energy released will be 1.33 mm/yr. x the latent heat of fusion (93.024 Watthr/sq.m) = 123 Watthr/yr. sq.m which resolved to 0.0141Watts/sq.m average radiation over the period.
( Hope I have got that right!!)
Also there is very little CO2 up there.
Heat, as we measure it, is the kinetic energy of molecules. The phase transition from liquid water to gas absorbs a lot of energy without any apparent increase in the “heat” of the water. This energy is supplied at the air/ocean interface by both the air and the ocean, cooling both with the greater amount coming from the ocean as it is almost always warmer than the air.
Now you have evaporated this water and its molecules join the molecules in the air, increasing the density and total kinetic energy of the air. Since we measure temperature (heat) and pressure as the number of molecules banging into our sensors, we see this result as an increase in atmospheric heat.
Entropy wants to dissipate any concentration of energy or molecules. The result is that gravity is defied and our dense kinetic parcel of water vapor infused air rises. Atmospheric temperature decreases (lapses) with altitude in the troposphere because fewer molecules are banging against our sensors, and they are doing so with less kinetic energy.
Our kinetic parcel of water infused air loses energy from radiation and conduction as it rises. It spreads out as pressure decreases and fewer kinetic interactions take place. We see that as cooling. When our parcel cools the dew point, all the energy of the phase change our thermometers didn’t see at evaporation is released.
Well, maybe I should have just quoted Roy Spencer and said clouds are complicated. Much more complicated than “heat” heading to the poles, banging on CO2 molecules, and radiating to space.
Gordon: I believe you have just described how hot air balloons work!
Water vapor decreases specific air density. N2 = 28, H2O = 18, 02 = 32. This is why moist air rises.
I should think that half of the heat released by condensation (cloud formation) goes up, and half goes down. Much or perhaps nearly all of the up-going heat would be lost to space since it is released at high altitude where there is little water vapor or CO2 to redirect it. All in all, it seems that water, water vapor and cloud formation balance out impacts from CO2 at surface level quite completely.
More than half goes out to space at the altitude of the phase change. Most of the CO2 in the atmosphere lies below it.
Most of the CO2, and almost all of the H2O.
Izaak, you are correct but it happens at altitude where the re-emitted heat easily radiates ou to space. It is not a closed system
You are correct that it is not a closed system. The 0.6 W/m^2 that Willis mentions is the
net energy gain at the top of the atmosphere due to the increased green house gases. Thus
satellite measurements provide direct evidence of the greenhouse effect and how we are causing the
earth to store more energy. That energy has to go somewhere and the satellite measurements
that Willis discusses shows that a probable consequence of that increased in energy is an increase
in the evaporation of water at the surface due to an increased in temperature. Increased rains are not cooling the earth but rather evidence that the temperature is increasing as expected.
Izaak, Willis’s calculations cover only the sea areas and between 40N and 40S. There is another “third” which is land area plus excluded latitudes. Now on average, the effect will be lower in these areas. If it is, say 1/4, then that accounts for a slice of the difference. The earth was already warming from the Little Ice Age before there was significant possibility for any manmade warming so yeah, a small imbalance may currently be there and it is thought there is likely some error in these small energy quantities – 1 degree squares are much larger than a thunder storm. In reality, warming has definitely slowed since the 90s.
I am pretty sure that the rain-cycle cools the Earth. I have after all, stood in the nice fresh COOL air after a rain shower. That heat isn’t permanently stored, it goes up, and then up, and then up some more until there are not enough atoms to make any difference.
Here is a analogy: Say I have an air conditioner connected to solar cells, but today it partially cloudy so the air conditioner is not running well. Then the sun breaks out and my air conditioner is suddenly running better. More energy and yet I cool down. If you consider the water cycle to essentially be a heat-engine driven cooling mechanism for the Earth, then you get the same effect. It may or may not completely counter-balance incoming energy, but it will certainly offset some of it. Assuming of course that CO2 is modeled at all correctly in the first place (a BIG assumption).
Are copying and pasting?
Ya he owned goaled
Have another drink Steven.
And get one of the breathalyzer interlocks on your computer like courts make DWI offenders put on their car ignition interlocks.
Friends don’t let friends post while intoxicated (PWI).
Not even close to being right Stephen.
Will you ever grow tired of be-clowning yourself for pay?
First off, even you should be able to figure out that every drop that condenses had to have first evaporated. So there’s no way increased condensation would cause increased heating.
Secondly, as Willis pointed out, evaporation occurs at the surface, (which as the acolytes like to point out, is where we all live) while the condensation occurs 10’s of thousands of meters up. Where it is high above most (perhaps even almost all) of the green house gases, so it’s very easy for that energy to escape directly to space.
The condensation occurs in an updraft column that rises between 10 and 20 km above the surface. The heat is radiated into the stratosphere where there is little of anything to absorb it as it exits the the atmosphere. The water that falls back is much colder than the vapor that went up. The rising vapor also entrains warm air that expands as it rises and radiates heat. The cooled air contracts and falls down. It too is colder than the air that rose. Where did the heat go? Same place. Space.
Read up on heat engines.
“Between all of these, they form a very strong temperature regulating mechanism that prevents overheating of the planet.”
The effect, if not the purpose, of the mechanisms that result in global weather/climate processes, is not to “prevent overheating of the planet”. If solar irradiance increases or atmospheric heat losses to space decrease, the earth will heat up to a new equilibrium that is neither “over” nor “under” heated. The result then is a system that is, or at least attempts to be, at equilibrium with respect to all its energy inputs and losses.
The effect of these wind circulation processes (along with oceanic current processes) is to dissipate heat generated in the tropics (which naturally have the greatest solar heating) throughout the other portions of the planet that receive less solar energy input. These processes don’t act as some sort of thermal relief valve, as suggested by the author. Rather they are just the second law of thermodynamics in action, i.e., the constant search for a state of energy equilibrium.
Izaak. Yes there is transfer of heat to the upper atmosphere, but this rapidly risen water has bypassed most of the CO2 in the atmosphere and can be rapidly irradiated to space.
Willis has emphasized elsewhere that STORMS (which are INCRESSING in response to warming in the equatorial bands per this article) rapidly elevate lighter humid air within vertical storm columns to higher altitudes by CONVECTION …thereby avoiding mixing of this moist air with lower altitude cooler air…so lots of the heat escapes lower altitudes where it is more subject to CO2 entrapment.
Then at the higher altitudes the heat from the connected warmer “moister” air is radiated more readily into space…actually assisted by elevated CO2 levels.
Most of the energy absorbed by air and oceans in the tropics is NOT taken out of the atmosphere to space, but rather is transported northwards at high altitudes, where it gradually cools and then drops back down in altitude, creating an energy and moisture conveyor system that rises at the equator, then drops at the northern boundary of the northeasterly trade winds (northern hemisphere), at which that boundary area is referred to as the northern hemispheric “doldrums” that tend to experience relatively light and variable winds.
The “doldrums” occur near the Tropic of Cancer at about 23.5 deg N latitude.
North of the doldrums in the “middle latitudes” (30 deg N to about 50 deg N), the westerlies (actually southwesterlies) kick in and continue transferring heat energy northward and eastward. So yet another conveyor belt system is created, with the cooled air at around 50 deg N latitude dropping back down toward the sea or ground surface and the winds gradually reducing as one goes northward towards the pole where a third polar conveyor belt is formed.
In the southern hemisphere the same three conveyor belts and intermodal “doldrums” occur.
All of this, of course, has been known for thousands of years, especially by mariners and by farmers who pay very close attention to weather patterns.
You purposely highlighted the word “NOT” – as in “most of the energy absorbed” “in the tropics is NOT taken out of the atmosphere to space”. Yet, massive amounts of solar energy is imparted to our planet every single day. If the majority of it was not radiated to space we could melt aluminum cans on our sidewalks and trees would spontaneously burst into flames.
You then state most of the incoming energy is “transported northwards at high altitudes” “where it gradually cools”. How does it cool? Where does the heat go?
Multiple research efforts have proven that storms are not increasing.
Nor are the storms more violent.
“lighter humid air”?
“avoiding mixing of this moist air with lower altitude cooler air”?
Nonsense; except for sort of describing occasional thunderstorms.
Claiming that thunderstorms are not mixing moist convected and cooler air is daft.
CO₂ is 0.04% of the atmosphere.
CO₂ is infrared active over a very small band of infrared frequencies.
Water vapor, especially in humid air is far more pervasive and is active over a large portion of the infrared frequencies; in all three physical states, solid, liquid, gaseous.
Water vapor, as you tried to claim is a very active heat transport, via convection, physical state changes and infrared lapse rates.
CO₂ is a flea in the atmosphere compared to water vapor’s whale.
Willis just presented data that demonstrates that precipitation is increasing. There might even be fewer storms, but more water is evaporating (heck that is a major tenant of global warming theory…more heat = more evaporation…no argument from me on that basic physics) so it is either raining more or that water escaped into space.. (hint: it’s not the space thing).
There is of course some warm moist/dry cool air mixing in storms, but it is standard knowledge that storms deliver large REGIONS of downdrafting cool dry air around the storm…and large columns of convected warm moist air are carried aloft…THATS WHAT THE HELL CONVECTION IS. Aircraft flying through storm cells frequently hit UPDRAFT cells that are miles across…the plane is a accelerated RAPIDLY upward for many seconds WHILE TRAVELING AT 600 MPH.
You are wrong on both counts. There is more rain, and storms transport heat from the ocean surface to high altitudes Zby convection where it radiates much more freely into space.
This isn’t remotely contestable.
Exactly. We are living on one big heat pipe transferring heat from tropics to arctic/antarctic.
This heat pipe has two warm ends. High potential, local, when temperature with water source reaches around 28-29C, in this moment local water vapors have enough energy create local cloud/storm and precipitation. This is process described by Willis going on in tropics and middle latitudes during warm times.
Second warm end is low potential, where local water vapors doesn’t have enough energy to condense on place and they are traveling around globe to colder places where condensation will occur. This is typical cold rain condensation on Iceland or UK. Or snow in Arctic/Antarctic.
First process is responsible for keeping local temperature at 28-29C maximum. This is basic Earth thermostat.
Second process is responsible for averaging global temperature and keeping places with less solar irradiation from freezing.
I think a lot of very large places on this planet with less solar irradiation are, in fact, frozen.
Is this the source of the supposed tropospheric hot spot? The more evaporation and precipitation, the more heat that should be transferred to the cooler upper atmosphere from the surface.
The hot spot isn’t there so the heat must have gone somewhere else, either into space or spread more evenly throughout the rest of the atmosphere. If it spread throughout the atmosphere, is that the source of the reduced rainfall in those areas that get less than 20 inches of rain per year? The air would have to go higher in the atmosphere to reach the height at which the temperature is lower than the dew point for that air.
You are considering only a half of the cycle: evaporation, not condensation. I am afraid that any heat removed from the surface by evaporation re-emerges high in the atmosphere as a condensation heat. A total heat should be conserved, but distributed from the surface elsewhere, wherever winds blow it.
It’s actually the heat distribution causing the winds, not the other way around.
How can heat be conserved at the surface or even in the atmosphere if it heads out to space?
By condensing high up it has been moved closer to space.
Yes, but the heat is released above some appreciable fraction (depending on the altitude at which condensation begins) of the CO2 which is assumed to trap it, which is calculated using the entire thickness of the atmosphere.
And that heat then induces further convection, which lofts the heat very high (at the top of thunderstorm clouds, 40-50+ thousand feet) where it is even more easily radiated to space
Is is not then assumed that this heat is lost to space?
Yes indeed, condensation is a heat transfer from the surface where water evaporates, to the atmosphere where water vapor condensates, releasing its latent heat.
But there is also the other half of the radiative story :
– active gases do not only absorb or emit backward (mainly in the lower troposphere),
– from the mid upper troposphere (say 7 km) and beyond, heat is radiated into space (see [NASA 2009], Earth’s Energy budget) :
– the atmosphere radiates into space 170 W/m² in the infrared spectrum, much more than the 17W/m² it absorbs from the upward infrared radiative flux emitted by the surface.
Radiating heat into space is the only way for the atmosphere to cool down (since the surface is warmer, the atmosphere can’t transfer heat towards it) and this is done by active gases in the infrared spectrum (mainly CO2, H2O vapor and O3).
Cooler bodies certainly radiate toward warmer bodies. It is the *net* radiation that results in what we see.
From “Introduction to Heat Transfer”, Brown & Marco, pg 65:
“In general, the net radiant-heat interchange between a gas and a solid surface may be found from an equation of the type:
q = Ap(Ig-Is)
A is the area of the solid surface, p is the emissivity of the solid surface
Ig,Is is an intensity factro related to temperatures, partial pressures, and the length of the radiant beam path
Sorry but I never said that cooler bodies do not radiate towards warmer bodies.
I know indeed that in radiative heat transfer [Modest 2003], only the net radiative flux between two bodies has to be accounted for, and this is exactly what I was talking about in our case (see NASA 2009 Earth’s energy budget) :
– the net radiative flux between surface and atmosphere (12 W/m² is the atmospheric window) is 340 * (117 – 12 – 100)/100 = 340 * 5 /100= 17W/m² and it’s upward (from the surface to the atmosphere).
Furthermore, thermodinamics says that a cooler body can’t warm a yet warmer body (all heat transfer processes being taken to account) :
– heat can’t go from a cooler to a warmer body : see Landau reference below.
[Modest 2003] : Radiative heat transfer,
[Landau] : Landau & Lifchitz – Physical Statistics
“Sorry but I never said that cooler bodies do not radiate towards warmer bodies.”
“Furthermore, thermodinamics says that a cooler body can’t warm a yet warmer body (all heat transfer processes being taken to account) :
– heat can’t go from a cooler to a warmer body : see Landau reference below.”
If radiation from a cooler body is absorbed by the warmer body then heat *has* been transferred to a warmer body by a cooler body.
You won’t get a net heat transfer overall from cold to warm because sooner or later the cooler body will warm to equilibrium with the warmer body. But even in equilibrium there is a heat transfer between the two bodies.
Using the sea level guys method of extrapolating trends, this net cooling will mean the Earth will become a giant snowball in exactly 127.34 years (well ok, I made up that number but so do they).
Pretty cool Willis.
I followed a hunch that the TRMM data as shown in your figure 1 may not correspond well to actual land measurements. For example, the fig. 1 rainfall range for east Texas looks on the low side. Texas annual rainfall by county shows three dozen or so counties above 47 inches (1.2 meters), going up to about 60 inches (1.54m) for Jasper County. Your fig. 1 Texas rainfall is far lower than 1.2m in most locations. It would take about 5 Texas counties to equal a one degree grid cell, so the eastern Texas counties with higher rainfall concentrations should indicate more rainfall than your TRMM analysis shows.
Perhaps the TRMM data could be calibrated better to actual measurements over land, in a similar manner that satellite data is calibrated to weather balloon radiosonde data. Just a thought.
This paper may interest you.
Their Method of Analysis outlines the many steps to best match a model to TRMM model data. Further searches indicate great learning and work opportunities in model downscaling for aspiring number crunchers and forecasters, which can include ground precip measurements.
The key to better forecasts as they point out is to heavily rely on real world dense data collection networks and integration of that data to training the forecast model.
A lesson woefully lost on the GCM community.
I recognise the same thing. North Queensland Australia have an average rainfall of 2.5m. It should be coloured light blue.
One major question.
Who was measuring the rainfall out in the ocean and how accurate was it?
I suppose question #2 would be is it honest measurement. but we can leave that for now.
My understanding is that even Temperature is provided only by very sparse measurements and I would think true measurement of Rainfall would be much more difficult.
John – Please re-read the first sentence of the post, which explains that these are satellite measurements. A bit of follow-up googling can tell you a lot more.
“• Dry descending air between rain cells and thunderstorms allowing increased longwave radiation to space.”
I’m glad you finally mention this as an important mechanism in the atmosphere. It returns energy to the surface via gravitational potential energy and allows more solar radiation to the surface by preventing cloud formation, yet in general still allows more energy in the form of LWR to escape into space than the energy these areas receive directly from the sun.
There’s an offsetting warming that you’re not accounting for. When water evaporates from the surface, it cools the nearby water it evaporated from whuch in turn cools what that water is in contact with, which is mostly other water. When water condenses in the atmosphere, the latent heat is returned to the drop of water it condenses upon making that drop of water warmer than it would be otherwise. While some of this warmth may be radiated away or transferred by collisions with air molecules, the drop of water is also absorbing radiant energy, which in the steady state must be equal to the radiation it emits as warmer air molecules and/or friction transfer energy to the drop of water as if falls through the cloud. The difference between the temperature of falling rain and the temperature it would be if it returned all of the latent heat is representative of the energy driving weather.
The importance of this is that latent heat plays no role in the energy balance. All that enters the atmosphere is returned as either rain or weather which are otherwise improperly represented by Trentberth as ‘back radiation’ contributing to the RADIANT balance.
Latent heat plays a HUGE role in the energy balance. It is the main mechanism for transporting heat away from the surface.
Latent heat plays no role in the energy balance of the planet. Moving heat from point A to point B does not remove the heat from the planet. The only way heat can escape the planet is by means of radiation.
Wrong. Its not a closed system
Absolutely! But the oceans provide negative feedback, as Willis points out.
Gary Pearse posts: “can be rapidly irradiated to space.”
Thank you Gary, you’ve merely repeated what I said: ” The only way heat can escape the planet is by means of radiation.”
The Earth is a thermodynamic closed system: https://en.wikipedia.org/wiki/Closed_system#In_thermodynamics
Not withstanding rocket ships leaving the planet, the Earth is a closed system relative to the transport of energy by matter. Latent heat and thermals transport energy by moving matter around. Radiation is the transfer of energy by photons. As Coeur de Lion implied, latent heat only redistributes existing energy and represents neither a source or sink of radiant energy (photons).
“The only way heat can escape the planet is by means of radiation.”
Which is easier the higher you get in the atmosphere. Because this condensation occurs high in the atmosphere, (The bigger the storm, the higher the altitude) it is much, much easier for the energy to escape to space than when that energy is at the surface.
“Easier” isn’t the problem. The higher up you go, the colder it gets. The colder it gets, the less it radiates.
But it still radiates. If it didn’t radiate, there would be no falling air to balance out the rising air.
Air emitting photons does not cause it to fall. Ever hear of PV=nRT?
Re: Latent heat of evaporation.
Yes, the energy absorbed to make a raindrop’s worth of evaporated water is equal to the amount of energy released when that raindrop’s worth of water condenses.
WHERE that energy is absorbed and WHERE that energy is released makes all the difference.
Tropical storm cells transport warm moist air (from direct solar driven surface evaporation) almost straight UPWARD via CONVECTION in columns of air within storm cells… without losing much energy from mixing with cooler air on the way up. This transports bodies of air with relatively high radiative IR flux (heated in part by condensation) ABOVE most of the trapping CO2 (and other misnamed greenhouse gases) in the atmosphere…where it radiates vast amounts of IR into space. (CO2 actually assists this high altitude net-spaceward radiation).
The temperature of the rainwater is on the order of 20-25 degrees C cooler when it returns to the surface than the average surface water temperature was when it evaporated.
Ocean surface water temperatures end up some 5 degrees cooler than before the ocean surface temperature that triggered the storm to begin with.
The emergence of the LOCAL storm is (primarily) a function of surface temperature:
– cooler waters => less storminess
– warmer waters => more storminess
This is a global temperature regulation system that responds MOSTLY to Local water temperatures (other factors relating to evaporation are also involved like wind speed and sea froth…etc.) REGARDLESS of how the water got warmer.
Is this the only “emergent type” global temperature regulator? Maybe not…but Willis’ back of the envelope estimate in this article indicates that this phenomenon alone could result in a ECS below zero.
So, if you want to attribute all of the observed increase in oceanic evaporation to CO2 (which is very very unlikely) it may be causing a net cooling.
Did you notice the “away from the surface”?
To a higher altitude where it radiates away to space…
The problem with the higher altitude is that up there it is a lot colder. We all know that the surface radiates much more than the upper atmosphere because of the temperature differences.
Do you realize that a parcel of air/atmosphere is radiating as it ascends and that will account for a significant portion of its cooling as it reaches altitude?
“significant portion ”
You must not know about PV=nRT
Congrats Alastair Bicknell
You have actually understood how of GHG:s work. They warm the surface by moving radiation in their absorption bands to a higher altitude where temperature is lower, and radiation therefore weaker.
The main mechanism for transporting heat away from the surface is radiation and even Trenberth agrees on this according to his energy balance diagram. The average surface emissions are about 390 W/m^2, while the energy transported from the surface into the atmosphere and back via latent heat and rain/weather is only about 90 W/m^2, where most is ultimately returned to the surface as liquid or solid water and the rest powers the weather.
To the extent that some of these 90 W/m^2 were radiated away from the planet, it just offsets the required radiant emissions originating from surface photons, but has no influence on what those radiant emissions must be which is a consequence of COE.
Since only the liquid and solid water in clouds is capable of radiating latent heat energy away and cloud water is tightly coupled to surface water by the hydro cycle, we can consider the absorption and emission of energy by cloud water as proxies for the required absorption and emission by the surface. This approximation is particularly useful when considering averages integrated over a period of time longer than the nominal period of the hydro cycle. Also consider that In LTE, the liquid and solid water in clouds must be emitting the same amount of energy that it’s absorbing, moreover; half of what it emits is directed back to the surface.
No notEvil, you misinterpret Trenberth’s diagram, as is common. Total IR to the sky is fore-radiation minus back-radiation which is 396-333 = 63 W/sq.m. Which is only 2/3 of evaporation, triple that of convection, 1/6 of sunshine during daytime. Go outside and “feel it” on your face.
No. It’s improper to consider the return of latent heat and thermals or the redirection of solar energy absorbed by clouds as a radiant return to the surface. By your logic, the total radiation into the sky would be zero, as in the steady state, all of the energy leaving the surface must be offset by energy entering the surface. Radiant energy is radiant energy independent of its wavelength and the radiant balance establishes a balance that includes LWIR photons and visible light photons.
Trenberth incorrectly assumes that a large fraction of the 240 W/m^2 arriving from the SUN is intercepted by the atmosphere and redirected to the surface as LWIR. To the extent that this occurs, only the water in clouds can do this, and it’s still solar forcing as far as the surface is concerned. Moreover; the water in clouds is tightly coupled to the water in oceans and for averages longer than the period of the hydro cycle, absorption and emission by the water in clouds is a proxy for absorption and emission by the water in the oceans.
Not evil: I’ve only once been in a tropical rainstorm, but what I can recall most vividly is that the rain was cold – a lot colder than the sea water that I was standing in. So on the basis of that one observation (how’s that for rigorous, robust scientific data collection?) I would submit that there is a net cooling at the surface, which is the key point of Willis’s observations. And which must be balanced by a net warming in the upper atmosphere where condensation is occurring.
To amplify this a bit, freshly condensed raindrops up aloft will be warmed by the latent heat of the phase change, but they can give up some of this heat to the surrounding air by simple conduction. Plus, on their 10-kilometre trip back to the surface, they will presumably be further cooled by re-evaporation. Raindrops falling through a column of air are going to evaporate more readily, just as my soup undergoes enhanced evaporative cooling when I blow on it.
Net surface cooling is what you need to stop a tropical thunderstorm. If there was no net surface cooling, I would conjecture that thunderstorms would just keep on thundering away for ever.
Some of that temperature difference is the source of energy driving the weather. The point is that the drop of water is warmer than it would be otherwise. As I said before, some may also end up be emitted into space or back to the surface as the emissions of a condensed rain drop. In this case, this radiant energy is in lieu of radiant surface emissions that otherwise must eventually be emitted into space or returned to the surface. This results in surface emissions absorbed by the atmosphere and returned to the surface that are otherwise not needed for radiant balance and instead applied to offset latent heat.
The question this raises is what effect do latent heat and thermals, plus the return of their energy to the surface (incorrectly referred to as ‘back radiation’) have on the sensitivity, average temperature and the corresponding average emissions other than the effect they are already having?
As an aside, consider that raindrops falling to the ground convert some of the potential energy of water lifted against gravity into friction as the drop falls. The terminal velocity of a raindrop is rather low and the friction warms it. One thing that’s often ignored is the source and disposition of this potential gravitational energy which is the same order of magnitude as the latent heat retained in cloud water. This energy is tangible as the source of hydroelectric power.
co2isnotevil: you have fallen for one of the oldest tricks in the book, confusing gross and net energy flows.
The radiative flows are given as gross, the convective as net.
For those 90 W/m2 to be the total convective heat flow from the surface would require the rain/snow to be at 0 K when returning to the surface. They are not, not even in inland Antarctica.
There’s no confusion here. It should be clear that most of the energy fluxes I’m considering arise from separating radiant from non radiant energy per direction in/out of the planet and in/out of the surface where there’s no offsetting assumed between in and out. It’s a given that their average differences across a Gaussian surface dividing the planet’s emitting surface from space must be zero in the steady state. Otherwise, the points along that Gaussian surface will heat or cool without bound. The virtual surface of Earth whose temperature we care about is an example of a Gaussian surface defining the ocean surface and bits of land that poke through. The spheres defining TOT or TOA are also instances of a Gaussian surface.
The issue seems to be whether or not there’s any net conversion of radiant energy to non radiant energy or visa versa within the steady state LTE atmosphere. It’s convenient to distinguish them as energy transported by photons and energy transported by matter. For matter to be in LTE, it must be absorbing the same as it’s emitting, so the definition of a steady state LTE combined with Kirchoff’s Law indicates that there’s no net conversion either way.
The 90 W/m^2 of latent heat ‘flux’ corresponds to the latent heat from the average rate of evaporation of about 1 m per m^2 per year. It’s neither convection or radiant and just potential energy entering the atmosphere by matter rising against gravity. It’s return to the surface is largely by friction and conduction and not by the transfer of photons or by convection. This isn’t to say that some of the energy carried by matter into the atmosphere couldn’t be returned by radiation, only that it doesn’t matter since any one Joule is no different than any other.
The only confusion arises from Trenberth incorrectly conflating the energy transported by matter with the energy transported by photons.
CINE – As several people have already pointed out above, the fact that you “lose” the latent heat of evaporation at the surface, below the entire atmosphere, and “get back” the latent heat of condensation at several kilometers of altitude, above much of the atmosphere, makes a big difference overall.
If you wanted to cool a hot space in a cold ambient, you would want to maximize the thermal contact of warm substance with the cold ambient. Having the condensation occur high up, where it can readily radiate to deep space, accomplishes this.
Nope. Convection transports the warm moist air (from evaporation) to high altitudes – without much mixing of cooler air on the way up where the latent heat of evaporation is released during condensation. And, as is mentioned in a dozen other comments here, that very high altitude warmed air radiates vast amounts of IR net-spaceward (actually assisted by CO2)…never to return to earth.
The water that comes back down to the surface is WAY colder (it is cold) than the average ocean surface temperature from which the water evaporated.
This is pretty basic stuff.
Thank you so much for the education. So many of you regular posters do great works and I really do appreciate it.
I would suggest though you say the way or skin is cooled and not our body. The regulation of body temperature is highly dependent upon physiological response in us mammals.
It’s surprising how the Atlantic tropical cyclone basin does not show up in the precipitation data at all, suggesting no regular pattern to cyclone paths in the 18 year period.
There has been no increase in total cyclone energy over this timespan.
Exactly. In fact there is no CO2 or warming SST signature that I can see in Global ACE.
The TRMM data should be informing the model community how to improve their models. I doubt any of them are serious about trying to get their models to fit observation though.
The hilarious thing is many of the so-called “State-of-the-Art” modern AOGCMs still predict (or “create”) two ITCZs for the Pacific, one north and one south of the equator. Modellers that “correct” that problem have models that run far too hot for their comfort.
Anthony highlighted one such research paper lamenting that problem in CMIP5 models here at WUWT in 2015.
That tells you right there that their rainfall patterns and total precip estimates are garbage, and simply manipulations of tunable parameters without a clear idea of what’s going on. And if their rainfall estimates are thus garbage so too are the models’ estimations of latent heat transport through the lower troposphere to the tropopause. Yet all these Don Quixote’s of the Climate Simulation community model ever onward and say Screw the satellites and their inscrutable data. All of this of course is intimately related to observationally absent, but CMIP3/5 model-predicted tropical hotspot in the mid-troposhere as a unique fingerprint of GHGE amplification by water vapor.
Giddy-up Rocinante!! CMIP6 gravy train and sweet Dulcinea Awaits!
It is always interesting to read your articles Willis, you are good at finding an original twist on things.
However, I think you have a big error here. If I understand correctly, the greenhouse gas increase is 0.03 to 0.06W/m2 per year, right? But the 1.33 mm extra rain was 2015 vs 1997, right? Then the cooling for the entire period is 0.1 W/m2, not per year.
Jan, good to hear from you. The rainfall (on average) increased by 1.33 mm per year. So we need to compare that to CO2 forcing per year.
Over the period 1997 to 2015, rainfall increased by an amount equal to 1.33 mm per year.
Willis; love your money quote “the calculated increase in warming radiation from GHGs was more than counterbalanced by the observed increase”
Reality trumps the models, yet again.
I notice with my “calibrated Mark VII eyeball” that the atmospheric demarcation doesn’t align with the equator by a large difference biased northward. Perhaps land area v ocean area makes the difference. If so and we are looking at climate and not geography what do you think about studying a Northern PseudoHemisphere versus Southern PseudoHemisphere actually set at 5-8° N latitude?
By the same wild thinking we might explore similar pseudohemispheres for equal ocean area and also equal land area.
Owing to the alignment of perihelion with the seasons, the solar energy received by the Southern tropics is a quite a bit larger than the solar energy received by the Northern tropics, especially relative to the forcing said to arise from doubling CO2. This could potentially push the ITCZ northward by distributing the larger amount of energy over a larger amount of surface, given that ocean surface temperatures tend to saturate at about 300K limiting the maximum emissions from ocean covered surface.
co2isnotevil April 29, 2019 at 3:43 pm
While this is widely believed it is not true. You are correct that when the earth is closest to the sun, the strength of the sun is at a maximum. And when the earth is furthest from the sun, the sun is the weakest.
However, when the earth is closest to the sun it is moving the fastest. And when the earth is furthest from the sun it is moving the slowest.
This means that it spends less time in the hot zone, and more time in the cool zone. And the net result is that the solar energy received by the Southern hemisphere is exactly the same as the energy received by the Northern hemisphere.
While your point about orbital velocity is correct, when I integrate un-nornalized solar data over a year, the S gets an average of 10 W/m^2 more than the N before accounting for reflection which is half of the average 20 W/m^2 difference between perihelion and aphelion. Interestingly enough, after reflection, the average incident energy per hemisphere integrated over a year are within 1 W/m^2 of each other owing to more clouds in the S, while the emissions per hemisphere are about 7 W/m^2 more in the N owing to a higher average temperature. The point that seems to be missing is that that a faster orbit at perihelion and a slower orbit at aphelion do not exactly cancel. The reason is that the orbital velocity is proportional to 1/r, while the solar energy is proportional to 1/r^2.
Your point has also been used to justify the use of AU normalized solar data for climate modelling. This ignores the dramatic asymmetries in the two hemispheres response to incident solar energy. In the winter, more N land means more N ice and more reflection, while in the S, more water means a lower reflection without clouds. In the S, the snow belt is over water where snow is harder to accumulate, while in the N, the snow belt is predominately over land and snow accumulates readily. Owing to more land in the N, the seasonal temperature range at the surface is about twice as large then in the S while the N average temperature is about 2C warmer since land has no upper temperature limit like the oceans have (about 300K). I’m not exactly sure what ModelE uses for its solar input, but I’ve been unable to find anything but AU normalized solar data from NASA or NOAA. The raw TSI data I use comes from the University of Colorado (SORCE TSI data set).
My point is that there’s a complex interaction of between asymmetric seasonal solar input and an asymmetric seasonal response per hemisphere, the consequences of which are widely unacknowledged yet they are crucial relative to entering and exiting ice ages.
Rob_Dawg April 29, 2019 at 1:14 pm
This is actually done for some studies, using the meteorological hemispheres rather than the physical hemispheres.
It would be interesting to see how this and the cloud cover (from https://isccp.giss.nasa.gov/analysis/climanal1.html ) correlate and how they have over recent times.
The interesting point in the cloud cover is that it declined from around 1987 to about 2000 and since then has been gradually increasing.
Thanks, Willis. Heat engines rule. And govern (as in governor mechanism.)
For those who commented above with the sense that precipitation heating only moves heat from one place to another, consider that NASA as an institution knows perfectly well how heat engines work and how this concept applies. Here are two quotes from a NASA Earthobservatory website article “Climate and Earth’s Energy Budget” from January 14, 2009, authored by Rebecca Lindsey (this article can still be found by searching):
“The climate’s heat engine must not only redistribute solar heat from the equator toward the poles, but also from the Earth’s surface and lower atmosphere back to space. Otherwise, Earth would endlessly heat up.
Earth’s temperature doesn’t infinitely rise because the surface and the atmosphere are simultaneously radiating heat to space.”
And “At an altitude of roughly 5-6 kilometers, the concentration of greenhouse gases in the overlying atmosphere is so small that heat can radiate freely to space.”
So the greenhouse effect diminishes with altitude, and the heat engine delivers it there, as high as necessary, to supply the variable emitter. The precipitation rate indicates the performance of the heat engine.
I’m replying to my own comment here to add a screenshot of the WSI Radar Summary image, which is freely available on the web. This is from a short while ago. Altitudes are given in three-digit flight levels, e.g. 500 = 50,000 feet, which is about 15 km. Springtime in the U.S. brings convective weather, illustrating the powerful localized heat-engine nature of the atmosphere’s response to temperature and water vapor at and near the surface. This response is promoted by the strong greenhouse effect at low altitudes. The radar returns include some orange, which corresponds to a rain intensity of about 1 inch per hour, which implies upward heat delivery of 16,000 W/m^2. My point: Willis gets it exactly right to emphasize how precipitation should be understood. Cooling by evaporation at and near the surface, heating by condensation and freezing at high altitudes where heat can more easily escape to space. Watch it happen yourself, and lose the fear of greenhouse gases.
Picked this up from a commentator on JoNova blog. Graphs of temperatures around the world, quick summary the sky is not falling.
It is revealing to compare the 2 Watts/sq.M. (from 280 pre-industrial to 400 ppm today) that the CO2 radiative forcing equation yields, to what is shown from an image search on “Uncertainty in Global Energy Balance”…
Good stuff, Willis. I wish ‘official’ climate scientists produced straightforward illustrations of phenomena from the superb data that is actually available without sticking their fingers and homemade statistics into the process.
Question. Is the 1/3 missing from the balance simply supplied by the effect of the land masses?
Willis, surface cooling from increased evaporation is balanced equally by atmospheric condensation. The net is zero. Moving heat from point A on the surface to point B in the atmosphere does nothing to cool the planet. The ONLY way for heat to escape our planet is via radiation.
Lionheart, the heat is removed from the surface and released up high in the atmosphere. Per NASA, from a comment above:
So moving the heat from the surface to the upper troposphere assuredly cools the planet.
It can only be ‘released’ after it condenses which means it can only be released by clouds. But, when emissions from cloud tops reaching space are measured by weather satellites, they are consistently less than emissions by the same surface under clear skies. It seems that the net result of water vaoir is to reduce the emissions by the planet.
Obviously. Cloud tops are far cooler than the surface underneath. You would have a much different Planck spectrum. The other difference is that cloud radiation is diffuse.
The design of a spectrophotometer is such that it ‘looks at’ a narrow cone. It just doesn’t see as much light from a diffuse surface. To correct for this you need an algorithm of some kind. Clouds have different densities of droplets and sizes so you would need a variable algorithm depending on the situation. Results could be way out at times. Not my job or headache to fix it.
Once you get a few meters above the cloud tops, cloud emissions are no more diffuse than surface emissions a few meters above it, whose emitted photons also leave in all directions. Cloud emissions originate from different depths, but from above the cloud, the depth where a photon was emitted is irrelevant.
Satellite sensors are tuned to the transparent parts of the spectrum, so it’s relatively easy to infer the relative emitted surface or cloud power by the relative strength of emissions in the transparent bands and convert to a temperature using SB. Of course, you need to make adjustments for varying water vapor and ozone concentrations which are not as well mixed as CO2.
A significant difference is that there’s little or no water vapor between cloud tops and space, thus the GHG effect from water vapor has little effect on cloud emissions into space.
A complication is that clouds are not completely opaque to surface emissions and if we consider that the average cloud coverage is about 66% which includes partly cloudy skies and thin clouds, on average about 20% of the surface emissions will pass through the cloud layer without being intercepted by cloud water and whose radiant emissions must be accounted for in order to establish actual cloud top temperatures. This is a more complex calculation and requires knowing more about specific cloud properties.
The wavelength where the Plank emissions are maximum is proportional to 1/T, where the average surface T is about 288K and the average cloud T is about 260K, so the peak average wavelengths of the resulting emissions varies by only about 1.5 microns.
I disagree with your definition of diffuse radiation. I am separating diffuse from lambertian. The ‘diffuse’ I am talking about is like the blue sky. Also the appearance of things through frosted glass. These are both not limited to a few meters. Clouds act in the same way. I remember some years ago, noting on an overcast day, that there were no shadows on any of the walls of a quadrangle 4 stories high and about 100 metres per side. I was there from early morning till late in the afternoon. There is no reason to think that the bottom of clouds would act differently to the top. It’s worthwhile googling ‘why are clouds white’. Specular reflection of visible light and IR are the same but transmittance will be different.
SB applies to a blackbody only. Throwing in a factor for emissivity is a joke. The emissivity of a non-gray body varies from wavelength to wavelength. the result is that the temperature/ energy function is non linear. Some people like to use albedo for reflectance, which shows a straight horizontal line between 0.3 and 3 microns. Nothing could be further from the truth. As far as I’m concerned, these people are either ignorant( lack of knowledge) or just plain lazy. Information on reflectance is available free online and the calculation for emission is straightforward on a spreadsheet program. Maybe the results doing things the easy way are similar. I just prefer to use better methodology.
You’re referring to a shadow from visible light and not an LWIR shadow, the difference being that visible light is sunlight filtered and diffused by clouds, while the water in clouds is the actual emitting source of LWIR returning to the surface.
The SB Law applies to ALL matter absorbing and emitting energy. If you think otherwise, what law(s) of physics do you propose quantifies a different relationship between W/m^2 of planet emissions and the EQUIVALENT surface temperature? Keep in mind that the EQUIVALENT average surface temperature based on a BB analysis and the actual average surface temperature are virtually indistinguishable from each other. Even Trenberth acknowledges that this approximation is good enough.
The SB law relating the equivalent temperature to emissions is independence of a Planck distribution. Even a laser beam has an equivalent temperature based on its W/m^2. Relative to Earth, the planets emission temperature based on Wein’s displacement (which does depend on a Planck distribution) is close to the average surface temperature while the equivalent temperature of these emissions is only 255K because some of the energy in absorption bands is absent. This temperature matches the 255K temperature of the solar input which is very close to an ideal Planck spectrum where Wein’s displacement and SB get about the same temperature.
How can you explain this plot of the Earth’s behavior without acknowledging the relevance of the SB Law? The green line is the expected behavior based on the SB law for a gray body whose emissivity is 0.62 and the red dots are 3 decades of gridded monthly measurements of the planet’s emissions vs. the surface temperature aggregated into 2.5 degree slices of latitude. The larger dots are the averages per slice across 3 decades of satellite measurements. Repeatable tests of the prediction of SB are what convince me that SB must apply as the laws of physics require.
I frequently see both sides of the debate deny the relevance of the SB Law and this couldn’t be more wrong given how the planet actually behaves. Of primary importance is the T^4 dependence between W/m^2 and temperature which is ignored by the IPCC so approximate linearity between T and W/m^2 can be incorrectly presumed to represent the actual linearity required by Bode’s feedback model.
Of the terabytes of data I’ve studied from many sources, the relationship between the surface temperature and planet emissions as it conforms to a gray body whose emissivity is 0.62 is the most tightly regulated relationship there is. A consequence is that the 62% of the surface emissions that are emitted by the planet is nearly constant from pole to pole and land to sea and mostly independent of either temperature or insolation. Without clouds, the fraction is higher, with clouds it’s lower and the average clearly converges to 0.62.
A constant surface power gain of 1.62 (1/0.62) is the very definition of a linearity and confirms that superposition in the power domain is an undeniable truth.
You seem to forget Willis that the “upper atmosphere” is part of our planet. So moving the heat from one part of the planet to another part of the planet isn’t really cooling the PLANET.
The only way the planet can cool is via radiation.
Radiation is a lot easier when the heat is transported high up into the atmosphere.
The more rapidly heat is moved from the surface to the upper atmosphere, the more rapidly this radiation will take place.
You’re being silly. If the heat didn’t get moved from the surface to the upper atmosphere there would be far less heat to radiate away. If the heat remained at lower altitudes less would radiate away.
Hence, the movement of the energy so that it has a higher chance of radiating away certainly can be called cooling the planet.
The heat which is moved upward is in the form of water vapor. When it condenses to liquid water at high altitudes, it releases the heat of vaporization which was added at the earth’s surface by evaporation. This is mass transfer of material with potential energy (the heat of vaporization).
This relates to my question – ‘Moving surface air to the upper troposphere where it is above most GHGs and freer to cool to space.’ It is said to leave most of the GHG behind.
I thought that CO2 and air are a mechanical mixture with a small (approx 500ppm) concentration of CO2. What mechanism would cause the CO2 to separate so that it, as a greenhouse gas, would be left behind and NOT go with the rest of the air as it rises to the stratosphere and spreads?
I don’t recall hearing of a mechanism that would do this on a world wide scale (and I’m not talking about plants/animals metabolizing the CO2 and sequestering the carbon).
Willis, you cite:
“At an altitude of roughly 5-6 kilometers, the concentration of greenhouse gases in the overlying atmosphere is so small that heat can radiate freely to space”
I used to think like this, but after second thoughts, at that altitude it can also radiate DOWNWARDS.
A drop of water in the ocean surface will radiate upwards only, then some of it will be re-radiated by GHGs downwards. A drop of water high in the atmosphere, on the other hand, will freely radiate upwards to space (no GHGs to stop that) HALF of what it radiates AND will radiate downwards to surface the other half. Which in the end may be a similar situation than what we had at the ocean surface in terms of net emissions to outer space. Or am I mistaken?
Nylo: What do you think happens to the IR radiation that travels back to the surface? Does it warm the surface? If the surface is warmed what does that cause to happen?
From the height we are talking about, less than half of the radiation is back toward the surface. Calculate the angle the earth subtends at that height.
What’s blithely overlooked here is that heat escapes our planet much more readily from point B than from point A.
Don’t forget that half of the heat released in the upper atmosphere does not escape to space but goes in the opposite direction and strikes the surface.
Very little if any of the heat released in the upper atmosphere strikes the surface. Almost all, if not indeed all, of this down-welling radiation is re-absorbed by greenhouse gases and “Thermalized,” converting to heat absorbed by the atmosphere far far above the surface. The average Mean Free Path of 15-micron radiation is around 30 meters at the surface, gradually lengthening as altitude is raised, but radiation released at 5 kilometers has little chance of reaching even 1 kilometer altitude.
This non-controversial factoid completely invalidates the farcical Trenberth cartoon. The atmosphere cannot heat the surface, nor can it heat itself.
“he atmosphere cannot heat the surface”
WRONG…..happens all the time in the Northern Hemisphere.
When the wind is coming in from the South, it warms things up. This usually happens after a snow storm, when a southerly breeze warms the surface and melts the snow.
Now Michael, Trenberth did a good job. Willis has a more explanatory one he once published here on WUWT, and Judith Curry has one with the ranges. All very useful to those of us “in the audience”….
Mike Borgelt April 29, 2019 at 5:38 pm yes it warms the Surface, but via Radiation.
Sorry should sat NOT by LW Radiation.
No one needs to explain this to ME. Professor Wang could explain it to YOU, if he is still with us.
Michael Moon: Why is the heat not “thermalized” to begin with? Why is it first radiated and *then* thermalized? A molecule that has absorbed heat radiation can do one of two basic things. It can re-radiate it or it can vibrate faster. In the first case some of the downward radiation will be sent back toward space. In the second case it raises the probability of a collision with another molecule thus transferring some of the heat energy to a molecule that can re-radiate it or pass it on.
Radiation, once absorbed, can either be re-radiated or “thermalized.” At lower altitudes the atmosphere is denser, and thermalization is much more likely.
Actually, your question seems to confuse “heat,” which is the average kinetic energy of the molecules in a quantity of matter, with “radiation,” in this case long-wave Infrared.
What you mean by “thermalized” is not obvious. Are you saying that the increased “energy” of the molecule is passed on to a different molecule? If so then what keeps that other molecule from radiating away the increase in energy?
I’m not confusing anything. Energy is energy. A molecule that has absorbed energy can either pass it on through a collision with a less energetic molecule or it can radiate it away. It’s not any different than heating the air in a hot air balloon.
CDL –> Even assuming that 1/2 goes up, some percentage of that going “down” doesn’t reach the earth because it is a sphere. At 50,000 feet what is the percent that reaches back to the earth?
That would be true if clouds had zero thickness (or nearly so). Only then could the upward and downward radiation be equal.
As it is, the condensation occurs throughout a thick region of atmosphere. Radiation from the very top of the clouds to space is roughly half of the emitted radiation. The downward component, however, is fully absorbed by the clouds below it, warming them, and causing further vertical convection to the very top, where the reabsorbed heat is once again radiated.
This is a much more complex phenomenon than the discussion here reflects, IMHO.
Radiation travelling down is blocked, radiation travelling up isn’t.
CdL, you are looking at this too simply. You need to look at the total flow of energy instead of the direction of radiation. Once you get very high in the troposphere most of the energy directed downward gets reabsorbed quickly. It never makes it to the surface. Same is also true of much of the energy radiated upwards but it travels farther on average.
When you average this out you get most of the energy going into space.
CdL – As I and several other commenters have pointed out upthread, the fact that condensation occurs above most of the atmosphere makes a significant difference. See for example:
but read thru the other comments as well.
I think few people understand just how vast the ocean is. I am in in Cabo San Lucas, out of San Francisco on a sailboat bound for Panama.
The depths, a few miles off shore, are 2-4 kilometers and it gets deeper as you go out. That is a lot of water.
A lot of water that buffers heat, CO2 and all manner of stuff we dump into it. Where did all that stuff come from. Well, the ocean and from land.
Anthropogenic? Maybe a little bit, but the ocean laughs at our hubris. Insignificant compared with natural processes.
Not very scientific, I admit. But common sense for mariners.
Keep up the good work!
Thanks, Jim. Indeed, the size of the ocean, and its buffering value, is almost unimaginable.
As a sailor, you might enjoy some of the sea stories over at my blog, Skating Under The Ice.
Stay safe on the ocean, one hand for the ship, one hand for you …
R.I.P. “positive water-vapor feedback.”
So …. there ya have it. Trentberths missing heat is wrapped up in an increase in kinetic energy driving the increased rate of circulation of the tropics resulting in an increase in an extra 1.3 L of rainfall per meter.
Can we go home now?
Willis, I love your work and the idea that increasing rainfall will cool the earth is certainly worthy of investigation, but I think you may have gotten your units mixed up. You stated that “Figure 3 shows the annual change in rainfall, in millimeters per year, on a 1° latitude by 1° longitude basis” which was reported to be 1.33 mm per year from 1997 to 2015. But, then you do your calculations for the cooling caused by 1.33 mm of rain per square meter, not per 1° latitude by 1° longitude?
James, the increase in rainfall is 1.33 mm/year. Not 1.33 mm per year per 1°x1° of lat/lon. Not 1.33 mm per year per square metre. Just plain old 1.33 mm/yer.
To calculate the energy involved, it’s calculated in watts/square meter. So we have to look at how much energy is involved on a per square meter basis. This is equivalent to the amount of water evaporated (or condensed) per square meter, which is 1.33 liters per square meter.
The math to get 1.33mm was done based on the 1-degree grids.
It isn’t a total of 1.33mm for the grid. It is across the entire grid. Think of it as water 1.33mm deep across the grid…it is still 1.33mm deep on a square meter area as well.
Just watching this Youtube video that just surfaced on Facebook https://www.youtube.com/watch?v=oYhCQv5tNsQ&feature=youtu.be&fbclid=IwAR2ey8K5n9MG3yXp2vHc-6kKiAL_cYlC-x5kLmH8jQDu9rmb15b49G9wu3E
Before wondering what it does to Earth’s average surface temperature, we should wonder what it does to the temperature record. Can you really treat the mean of min/max temperatures as an intensive property like concentration and calculate for areas with missing data?
Looking at those charts led me to observe that more rain falls where there are large mountain ranges. No surprise, as with prevailing westerlies the clouds rise and can’t hold as much water vapor. For example, Australia lacks a western mountain range, resulting in a very dry continent.
Well yes and no
There are no significant mountains along the West Australia coast but there is a warm current so the rainfall in SW Western Australia is anomalously high.
Equivalent locations in Africa and South America are desert. Southern California is semi-desert; San Diego has an average annual rainfall of less than 300mm.
Northern Australian rainfall is dominated by the summer Monsoon
Much of Pilbara is actually rather high. But it is the latitude, not the mountains that matter. Compare Australia with similar latitudes in South America which has a very high western mountain chain
Pilbara = Atacama desert. Atacama is actually a lot drier
Perth = Santiago. Both have similar mediterranean climate, good wine-growing areas.
Tasmania = Chiloe. Both very wet, temperate rain-forest
You wrote, “I was also intrigued by how narrowly the rainfall is concentrated at the average Inter-Tropical Conversion Zone (ITCZ).”
Typo: ITCZ = Inter-Tropical Convergence Zone?
Thanks, Boulder, fixed.
I hate typos.
Well something must be wrong…I think I have got 2 meters of rain in my backyard this Spring! LOL
This is the wettest Spring I can remember here at this house. (about 20 years). It may be skipping the rest of Texas, but I think I could fill a lake with the runoff I have watched going past my house.
It must be global warming – after all they predicted this! (and ever other possibility)
April showers bring May flowers. I can remember very wet spring weather back in the 60’s.
Excellent article. Easy to see how your conclusion was reached.
Why do we not see more climate scientists dealing with real world measurements? It seems 99.99% of climate scientists concentrate on models and “tuning” them to meet some “global temperature”, however ephemeral that is. This just demonstrates how clueless the modelers are when it comes to writing equations that describe real world atmospheric conditions.
Climate scientists are basically only trained on models. Very little training on meteorological stuff. I do believe that is intentional.
Since CO2 is well mixed in the atmosphere, if you are above 90% of the atmosphere you are naturally also above 90% of the CO2.
The same goes for water, with the additional factor that cold air can hold less water, and the air at 50K feet is very cold.
I have no idea how this got down here, it was supposed to be a response to “nw sage April 29, 2019 at 6:31 pm”
The effect is much stronger for water since it condenses. Liquid or frozen water are not GHG:s, they are black-body radiators.
Just an off the wall conjecture. I wonder if this explains why they can’t find that “tropical tropospheric hotspot” . In other words the models are “right” but “wrong” because they don”t account for the cooling you just showed which obliterates the hotspot they were so sure must exist.
Willis: another fine piece of thought-provoking analysis.
I’m fascinated by the increased rainfall over the 17-year life of the project, and I’m particularly fascinated by the fact that so much of the increase is concentrated in the equatorial Pacific. Very little in the Atlantic or Indian Oceans.
I wonder whether that increase was steady over the life of the project, or did it accelerate during El Niño years? Possibly even reverse itself a bit during the La Niña years? If you have the data handy, it would be interesting see if there was a correlation.
Hi Willis and Smartrock:
It would be very interesting to see how that extra precipitation varied over the time period 1997-2015, and indeed it would also be very interesting to see that precipitation plotted against the Nino3.4 index or SOI, as the period of this study had a large El Nino close to the start and a large La Nina two thirds of the way to the end (with some other ups and downs).
Also, UAH shows TLT in very wet years is warmer relative to surface temperatures (which are cooler during wet years), and the reverse in very dry years- at least over land area of Australia. Moisture carries heat high into the atmosphere where condensation releases it where a proportion is radiated to space- more in wet years than dry years. Am I right or am I left?
My location on the map of annual change of rainfall is coloured green: annual change + 6mm a year. I thought – that can’t be right, we’ve been in drought most of that time. So I went to the rainfall data for the nearest weather station. I live in Australia, in far western NSW, and the nearest station is Mildura in Victoria, about 30km away. In this area there is usually just one weather station, or less, within each 1 degree lat/long grid.
So, here is Mildura’s annual rainfall from Jan 1998 to Dec 2014 (easier than including partial years). The long-term average rainfall (1949-2019) is 286.6 mm.
A dry year (also 96/97): 1998: 162.8mm.
Above average: 1999: 339.0, 2000: 330.2.
The Millenium Drought – nine years, with just two at or above average: 2001: 186.8, 2002: 192.2, 2003: 303.8, 2004: 173.2; 2005: 277.8; 2006: 123.0; 2007: 223.0, 2009: 232.8; 2008: 201.4;
The drought breaks, and how – twice the average: 2010: 597.0; 2011: 658.
Back to below average: 2012: 214.4; 2013: 213.6; 2014: 256.8.
So, how do you get an annual increase of up to +6mm? That would be an increase of up to 102mm over those 17 years. But the trend over 1998-2014 is average, way below, way above, then below. The average of these years is 275.6 mm, not much below the long-term average. I can’t find the average 1949-1997 to see if that differs.
Mildura’s high rainfall of 2011 was exceptional; 155mm (6 inches) fell in one day, 5 February, actually in just a couple of hours in the early morning – part of my roof collapsed, and there was major damage to roads and buildings. This was a genuine tropical downpour, the remains of Cyclone Yazi, which had hit Cairns nearly 3000km northeast. It moved inland, turned into a storm depression, was captured in the NW-SE trough across the continent and dropped its bundle on us.
Since 2014, the rainfall has been: 2015:240; 2016: 358.6; 2017: 269.6; 2018: 135mm. We are back in drought: in the first four months of 2019, there has been just 9.8mm (2004 was comparable with very low rainfall for the first four months).
This is just one location, but I am fairly sure that if I crunched the numbers for all that green area in Australia, the result would be the same, extremely variable rainfall, with no real evidence of an overall increasing trend.
Does Satellite IR sensing have enough resolution to detect this proposed “up to” 1 Watt/m^2 increase in net outgoing IR over the last decade from increasing ITCZ “storminess”?
If it does, we would have heard about it…No?
If it doesn’t, then the satellite measurements of reduced outgoing IR on the order of 0.6 Watts/m^2 from increasong CO2 over the last decade would also not be detectable.
Is that data available?
Perth coastal ranges get a metre a year and more. Not shown in your first maps.
Very localized as you will know if you are familiar with the area, once over the escarpment the precipitation drops very sharply. A hundred miles inland and you find salt flats.
The warmistas will not like:
**Which means that over that period and that area at least, the calculated increase in warming radiation from GHGs was more than counterbalanced by the observed increase in surface cooling from increased evaporation.**
Delighted that, at last we are discussing the influence of water on the environment. My long standing hypothesis being that the earth sweats to keep cool, just like we humans do, with the thermodynamics giving a great deal of support to this.
Delighted also that we have now, thanks to you Willis, a value for the increase in evaporation at some 1.33 mm/yr. over the period. The calculated upwelling of energy thus being correct at 0.104 Watts/sq.m.
I would, however be grateful for details of the IPCC calculation on the equivalent figure for downwelling change due CO2. This, for me has been lost in time and appears somewhat dubious. The calculation you give being somewhat sparse.
Back on earth we have good experience on what happens in this sort of situation as seen in the behaviour of our steam generating plants. These operate at constant temperature and pressure (generally as our climate?) and respond to an increase in energy input by an equivalent output of energy; all in balance. Similarly, I suggest with the climate in the presence of water.
Thus, back engineering this proposal we can suggest that the downwelling change (+ other) energy must be in balance at some 0.104 Watts/sq.m, or thereabouts subject to leads/lags etc.
This then leads to the question: If the IPCC reckon CO2 is responsible for a mere 0.06 Watts/sq.m, where does the OTHER 0.044 Watts/sq.m come from.?
Difficult to answer; but with many possibilities of which Albedo is one with solar and volcanic activity also on the list – all basic natural processes in which water itself also plays a part as a known greenhouse gas.
On a side issue: You say “This thermal circulation is greatly sped up by air driven vertically at high rates through tall thunderstorm towers.”
IMO a good proportion of this is due to the buoyancy of water vapor wrt dry air in conjunction with the thermal differential.
I have attempted to get a handle on this aspect by calculating the forces and potential velocities involved here; but am floundering a bit ! Any ideas on this.?
Generally I find that these buoyancy/thermal aspects get conflated in many papers and lead to incorrect assumptions in my view.
Enough for now. Very much appreciate your contribution.
PS: There is a not very good paper on this on my htp:// cognog2.com site; but I am not good at computer presentations., although it does give the basics.
Willis:Re your concluding paragraph.You make no mention of the water-air interface temperature change with increasing LWR due to CO2. The evaporative flux is controlled by the interface temperature, which must be calculated from a surface energy balance–which shows that an increase in LWR goes mainly to reduce.the heat loss from the ocean,not to increase evaporation.Your “analysis” simply ignores the role played by ocean heating.
For a relevant tutorial you can try http://www.temporalpublishing.com Click on STORE,Choose the text “Basic Heat and Mass Transfer”. Then click on Instructor and choose Supplementary Material,and then Supplements for Heat and Mass Transfer from the drop down sub-menu.See Supplement 8,in particular Section 8,pages 68-72.
Ocean evaporation is nearly 100% solar energy driven. ITCZ water temperatures rise on the order of 5 to 8 degrees every morning FROM NEARLY A KILOWATT OF DIRECT SOLAR RADIATION per m^2. A fraction of a watt/m^2 of LWIR back radiation is totally lost in the noise…even if LWIR were efficient in raising surface temperatures.
super cell thunderstorm height max at 20.7km
air pressure at 20.7km is 3.7kPa
co2 dia 0.7*10^-10m
this gives a mfp of .34*10^-4m
The time between collisions is 340ns
giving 2.9e6 collisions per second
time from the absorption of a photon by co2 to emission as another photon is microseconds (around 2us).
So it is 10 times more likely that the excited co2 molecule will transfer energy to other molecules by collision. even at 20km.
GHG concentration is low so the energy will likely be passed on to non-ghgs and will not be radiated until the energy is passed back to a GHG molecule (note that water vapour will be very low at this altitude and temperature). This leaves CO2 as the major radiator.
Note that there is still a vertical way to go before a ghg can radiate to space without encountering other ghg molecules.