By Richard Willoughby
May 2021
(The author appreciates the availability NASA’s Earth Observations satellite data sets used in this analysis.)
Now a four part series that analyses the role of atmospheric water in regulating Earth’s thermal balance.
Part 4: The Atmospheric Gear Change
Total Precipitable Water & Level of Free Convection
In Part 2 of this analysis it was briefly mentioned that the atmosphere cannot form a Level of Free Convection (LFC) unless the Total Precipitable Water (TPW) exceeds 30mm. The listed conditions below all create an LFC at 500m:
- Surface temperature 298K, relative humidity 52% and TPW 3.1cm
- Surface temperature 293K, relative humidity 71% and TPW 3.1cm
- Surface temperature 288K, saturated and TPW 3.2cm
This demonstrates that an LFC can form under widely varying surface temperature and relative humidity but TPW remains consistent close to 3.1cm for an LFC 500m above surface level.
Part 2 also quantified the rate of condensation at 7.3mm/day if all OLR exists via the atmospheric column. This condition certainly holds once the TPW reaches 3.1cm due to the high long-wave absorption of water vapour, water condensate and ice. With the LFC at 500m and TPW of 3.1cm, there is 2.3cm (23mm) of water above the LFC. It would therefore take 75 hours for the column to develop full CAPE. It is likely that divergence or other disturbance disrupts the full development such that any cloudburst is weak.
It is observed that cloudburst cycles become more frequent once the TPW reaches 4.5cm. Typical surface conditions for occasional cloudburst are 296K and 80% humidity. This results in the LFC at 2000m with 10mm of water vapour above the LFC and 7mm of water above the level of freezing if the relative humidity is constant. The full CAPE can be recharged in 33 hours and the cirrus cloud persistency is nominally 70% of the full CAPE development phase.
Atmosphere in Overdrive
An interesting observation results when combining an understanding of deep convection as discussed in Part 2 and above with the actual ToA outgoing EMR data analysed in Part 3. Here in Figure 17, the twelve monthly regression lines for the EMR versus TPW are replotted on a single chart.
Figure 17: Regression lines for twelve monthly plots of ToA outgoing EMR flux versus TPW
With reference to Figure 17, there is a vertical line shown at 4.5cm, termed “Threshold” that gives the least squares error to the points of intersection. This is the TPW where the atmosphere goes into overdrive and deep convection sets in. Above the Threshold, the atmospheric water provides cooling principally by regular cloudbursts catapulting water vapour above the LFC to form highly reflective cumulus cloud and then persistent cirrus cloud while the CAPE is recharging. Once deep convection sets in, the increased reflection of ToA insulation trumps the reduction in OLR so ToA radiating power increases.
Below the Threshold, the water vapour acts as a warming agent by reducing the radiating temperature of the atmospheric column thereby reducing ToA OLR without producing high level reflective cloud.
When the surface temperature is cooling, the slope of the regression lines or Atmospheric Water Cooling Coefficient (AWCC), introduced in Part 3, is negative. It is evident that there is a reduction in the radiating power of the atmosphere above the Threshold compared with the months where the surface was warming and the AWCC is positive.
Atmospheric water imbues the atmosphere with the ability to change gear in response to changes in the surface temperature. The ordinary gear and overdrive conditions are distinct around the Threshold TPW of 4.5cm. In ordinary gear, the atmospheric water is a warming agent and in overdrive it is a cooling agent. It is certainly not causing a “Greenhouse Effect” that is solely warming the planet. Atmospheric water is able to stabilise the surface temperature by allowing more surface insolation and reducing OLR power when the ocean surface is cool and restricting surface insolation more than reduction in OLR with reflective cloud when the surface is warm. Deep convection provides a precise regulating temperature of 30C annual average over open ocean warm pools.
Current climate models parameterise clouds and atmospheric water is treated as a “Greenhouse Gas” when it exists in the atmosphere as gas, liquid and solid. The solid phase is a key factor in the formation of reflective clouds. These phases are all responsive to surface temperature at the base of the atmospheric column and surface pressure to a much lesser degree in the observed range. The atmospheric gear change around 45mm TPW is not a simple process that can be emulated with a few cloud parameters.
Date Links for the Referenced Data
https://neo.sci.gsfc.nasa.gov/view.php?datasetId=CERES_LWFLUX_M
https://neo.sci.gsfc.nasa.gov/view.php?datasetId=CERES_SWFLUX_M
https://neo.sci.gsfc.nasa.gov/view.php?datasetId=MYD28M
https://neo.sci.gsfc.nasa.gov/view.php?datasetId=MYDAL2_M_SKY_WV&date=2021-04-01
https://www.pmel.noaa.gov/tao/drupal/disdel/
Note that the data was sourced for various time intervals, usually monthly, from these locations.
The Author
Richard Willoughby is a retired electrical engineer having thirty years experience in the Australian mining and mineral processing industry with roles in large scale operations, corporate R&D and mine development. A further ten years was spent in the global insurance industry as an engineering risk consultant where he developed an enduring interest in natural catastrophes and changing climate.
The primary thermal regulatory mechanism is the average global rate of convective overturning.
Water vapour being lighter than air and providing a radiating and reflecting condensate is more effective at moving energy up and down than is simple dry convection.
Thus for a water planet the effect of water in all its forms is to reduce the rate of dry convective overturning that would otherwise be required to maintain hydrostatic equilibrium.
kind of ‘Gain of Function’ more research required
Yes bring on the Chinese lab.
More important to me is how do you compare objectively the “greenhouse gas” impact when one is noncondensing.
The evidence is clear from this series and WE at some point the condensing gas is not a warming gas but a cooling gas the full mechanism is still disputed or debated but the impact is empirically observed.
A huge hole in the conversion of the AGW to CAGW that is such a current focus.
A gentle correction. Water vapor, unlike CO2, is a condensing gas. But it only cools AFTER it condenses (mechanism, releasing latent heat of evaporation to space closer to the ERL) and all of it never does. The rest still warms.
Net net, even after WE emergent Tstorm phenomena, humidity still warms. The issue is by how much. In several previous comments, plus posts over at CE concerning Monckton, have argued about half of modeled, and gave the observational and mathematical supports for that estimate.
The earth absorbs the sun’s radiation mostly from visible and short infrared wavelengths. It emits radiation at long infrared wavelengths.
Clouds have low absorption/emission at visible and short infrared wavelengths. They are close to black bodies at long infrared wavelengths. link
So, what happens when the bottom of a thick cloud absorbs energy radiated by the earth? Somehow the heat is transmitted to the top where it can be radiated to space. How that happens depends on they type of cloud. A quick web search doesn’t find a lot of research on that topic.
Read essay Cloudy Clouds in ebook Blowing Smoke. AR5 said clouds are the main feedback uncertainty (two ways: cloud feedback, and impact on water vapor feedback via precipitation), and cannot be modeled because of the scales involved. Clouds are parameterized.
The physical cloud feedbacks depend on cloud type, altitude, optical depth, and entrained water. For example, even tho high cirrus has almost no optical depth and very little ‘water’, it warms. The high wispy cirrus are ice, not liquid water. So transparent to solar, but opaque to IR.
WE idea of emergent thermoregulation is the essence of Lindzen’s adaptive iris (via cirrus) hypothesis from 2000. You can read about it at Climate Etc in companion essays by Judith (who interviewed Lindzen) and myself (who linked to his paper, simplified an explaintion of the hypothesis, and noted the impact (significantly reduced ECS) when newly incorporated into a climate model.
Willis is expanding on Lindzen’s Iris theory, detailing at least two emergent phenomena.
Smirnov in Journal of Atmospheric Science Research 2020, Atmospheric Carbon Dioxide and Climate, using Hitran got these number for IR downwelling:
Water molecules 166 W
Water droplets (clouds) 96 W
CO2 molecules. 58 W
CH4 molecules. 4 W
N2O molecules. 3
His methodology appears to be correct. Unfortunately there are some translation errors, which can result in one reading that doubling of CO2 results in 3C increase, when he actually calculated 0.6 C….
Water ice is the major player that gets forgotten. Without accounting for that, HITRAN results are meaningless.
I have seen measured monthly average OLR data oover the tropical oceans as low as 180W/sq.m with a surface temperature of 303K. Try to adjust HITRAN to get a figure like that.
CommieBob, do you know how much incoming TSI is absorbed by water vapor ( even in clear sky conditions) and does that absorbed energy then leave the earth more quickly then if it had reached the surface, earth or water?
Notice the values on the y-axis and their difference.
This doesn’t seem to show that water has little absorbance at short (near) infrared directly from the sun.
Richard Willoughby. Compliments, on your detailing the different trends causing a thermostatic stabilization of and limitation on ocean temperatures. You note about a month’s delay between insolation and temperature. See David R. B. Stockwell his theoretical discussions. He shows temperature varies as the integral of insolation. That causes about a Pi/2 (90 degree) nominal lag. (Different feedbacks lags between land and ocean.) Best David
Stockwell, David R.B. 2011. On the Dynamics of Global Temperature. August 2, 2011a. URL, 186, p.55. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.397.4553&rep=rep1&type=pdf
Stockwell David RB. Accumulation of Solar Irradiance Anomaly as a Mechanism for Global Temperature Dynamics August 9, 2011
https://www.researchgate.net/profile/David-Stockwell-2/publication/228521066_Accumulation_of_Solar_Irradiance_Anomaly_as_a_Mechanism_for_Global_Temperature_Dynamics/links/0a85e532e35ddb1e01000000/Accumulation-of-Solar-Irradiance-Anomaly-as-a-Mechanism-for-Global-Temperature-Dynamics.pdf
Stockwell David RB. Key evidence for the accumulative model of high solar influence on Global Temperature. 2011, Aug. 23
https://www.researchgate.net/profile/David-Stockwell-2/publication/228517399_Key_Evidence_for_the_Accumulative_Model_of_High_Solar_Influence_on_Global_Temperature/links/0a85e532e35de53d8a000000/Key-Evidence-for-the-Accumulative-Model-of-High-Solar-Influence-on-Global-Temperature.pdf
The best alignment of the AWCC and surface temperature is achieved by shifting the temperature 25 days. So it takes 25 days to get the atmospheric water response to the surface temperature.
And yes the heat uptake and hence temperature are out of phase with the insolation. Minimum warm pool area occurs in January when the insolation is at its peak and ocean surface has greatest exposure to the sun. This is simply a result of the high thermal inertia of the ocean mixing layer.
Outstanding work. A breath of fresh air seeing calculus used instead of simple linear algebra and simple averages to try and tweak trends out of non-linear continuous time series. The explanations are easy to follow and I see no apparent contradictions.
Jim – Not clear if you are making the comment to David Hagan or me as it is in reply to him but I will assume it to be directed at the topic of the blog rather than David’s links.
The corrected version of the entire analysis is accessible as a pdf document at this link:
https://1drv.ms/b/s!Aq1iAj8Yo7jNhEJT4abluzwqa5PD
I appreciate all the comments that got the document to where it is now.
Thanks.
“The concept of the “Greenhouse Effect” demonstrates a misunderstanding of how Earth’s average surface temperature is achieved. The energy balance of the oceans, and consequently the entire earth, are related primarily to the upper and lower thermostatic limits on ocean surface temperature. The area of 30C warm pools expand and contract in response to variation in the top of atmosphere insolation due to the orbital eccentricity combined with the extent of water surface exposed more directly to the sun. Sea ice expands and contracts in reverse to the warm pools but to reduce heat loss from water below the ice due to the low thermal conductivity of the sea ice. The temperature of the ocean water surface ranges from minus 2C (271K) to 30C (303K). It should be no surprise that the average surface temperature of the globe is 14C (574/2=287K) given the distribution of water having equatorial dominance over polar extent causing average ocean surface temperature higher than 14C and average elevation of land at 800m with more land at higher latitudes than equatorial resulting in average land temperature being slightly less than 14C.
Climate models are based on a flawed assumption. Until they can replicate the actual physics of deep convection tightly linked to surface temperature rather than the naive parameterisation of clouds they will remain nothing more than extended weather models with useful predictive ability of a few days.”
Unfortunately, AWCC is not a valid metric for assessing the heating or cooling effect of atmospheric water.
The problem is that it relies on TOA Total Radiated Power Flux, and TRPF will rise in any of the following situations:
Items #1 and #2 would reflect TRPF increasing because atmospheric water is cooling the surface.
Item #3 would reflect TRPF increasing because atmospheric water is heating the surface (or perhaps having no effect, in a context where other factors are changing the temperature).
You are interpreting increasing TRPF as always meaning cooling. However, when item #3 is in involved, increasing TRPF could actually be the result of a heating effect.
In summary, TRPF muddles together heating and cooling effects in a way that renders these indistinguishable via your current mode of analysis.
Because TRPF is a muddled metric for assessing heating and cooling, AWCC is also a muddled metric which conflates heating and cooling effects.