Guest Post by Willis Eschenbach
I have theorized that the reflective nature of the tropical clouds, in particular those of the inter-tropical convergence zone (ITCZ) just above the equator, functions as the “throttle” on the global climate engine. We’re all familiar with what a throttle does, because the gas pedal on your car controls the throttle. The throttle on any heat engine controls the running conditions by limiting (throttling) the amount of incoming energy.
Similarly, in the climate heat engine, the throttle is the tropical albedo (reflectivity). The tropical albedo controls how much incoming solar energy is rejected back to space at the hot end of the heat engine. In other words, the albedo throttles the incoming energy to control the entire system.
I have further said that the tropical albedo is a threshold-based and extremely non-linear function of the temperature. So I thought I’d use the CERES satellite data to take a look at how strong this climate throttle is in watts per square metre (W/m2), and exactly where the throttle is located. If such a throttle exists, one of its characteristic features would be that the amount of solar energy reflected must increase with increasing temperature. Figure 1 shows the results of that analysis.
Figure 1. Average change in reflected solar from a 1° increase in surface temperature. Red areas show greater reflection with increasing temperature. The change in reflected energy is calculated on a per-gridcell basis as the change in albedo per 1° temperature increase for that gridcell, times the average solar radiation for that gridcell. Gray line shows zero change in albedo with temperature. Dotted lines show the tropics (23.45°N/S) and the Arctic/Antarctic circles (66.55°N/S).
Clearly, then, such a throttle mechanism exists. It is also where we would expect to find it, located near the Equator where the maximum energy is entering the system. On average, the throttle operates in the areas enclosed by the gray line. I was surprised by the strength of the mechanism, however. There are large areas (red) where a one degree C warming in temperature increases the solar reflection by 10 W/m2 or more. Obviously, this thermostatically controlled throttle would be a factor in explaining the observations of a hard upper open ocean temperature of about 30°C.
The throttle mechanism is operating over much of the tropical oceans and even some parts of the tropical land. It is strongest in the ITCZ, which runs below the Equator in the Indian Ocean and over Africa, and above the Equator in the Pacific and Atlantic.
Next, it is worth noting that overall the effect of temperature on solar reflections is about zero (global area-weighted average is -1.5 W/m2 per degree, which is smaller than the uncertainty in the data). In addition, large areas of both the land and the ocean in the extra-tropics are quite similar, in that they are all just slightly negative (light orange). This is another indication that we have a thermoregulatory system at work. Since over much of the planetary surface the albedo is relatively insensitive to changes in temperature, small changes in temperature in the tropics can have a large effect on the amount of energy that is entering the system. Figure 2 shows the relationship (land only) between absolute temperature in °C, and the change in reflected energy per degree of warming.
Figure 2. Change in reflected solar (W/m2 per °C) versus absolute surface temperature (°C) over the land. Note that where the annual temperature averages below freezing (0°C), there is little variation in surface reflection with temperature. From freezing to about 20°C, the amount reflected is generally dropping as temperatures increase. Above about 20°C, there are two kinds of responses—sizeable increases or sizeable decreases in reflected solar with temperature.
Next, over the oceans the areas near the poles show the reverse of the behavior in the tropics. While the tropical albedo changes cool the tropics, near the poles as the surface warms, the albedo and the reflected sunshine decreases with increasing temperatures.
Figure 3. Change in reflected solar (W/m2 per °C) versus absolute surface temperature (°C) over the ocean, annual averages. Where the annual temperature averages near freezing, there is strong negative variation in surface reflection with temperature. From freezing to about 20°C, the variation is stable and slightly negative. Above about 20°C, there are two kinds of responses—sizeable increases or sizeable decreases in reflected solar with temperature, up to the hard limit at 30°C
What this means is that in addition to limiting overall energy input to the entire system, the temperature-related albedo-mediated changes in reflected sunlight tend to make the tropics cooler, and the poles warmer, than they would be otherwise. Clearly this would tend to limit the overall temperature swings of the planet.
Finally, the use of monthly averages obscures an important point, which is that the changes in tropical albedo occur on the time scale of minutes, not months. And on a daily scale, there is no overall 10 W/m2 per degree of temperature change. Instead, up to a certain time of day there are no clouds, and the full energy of the sun is entering the system. During that time, there is basically no change in tropical albedo with increasing temperature.
Then, on average around 11 am, within a half hour or so the albedo takes a huge jump as the cumulus clouds emerge and form a fully-developed cumulus regime. This makes a step change in the albedo, and can even drive the temperature down despite increasing solar forcing, as I showed here, here, here, here, and here
From this we see that the thermal regulation of tropical albedo is occurring via changes in the time of the daily onset and the strength of the cumulus/cumulonimbus regime. The hotter the surface on that day, the earlier the cumulus and cumulonimbus clouds will form, and the more of them there will be. This reduces the amount of energy entering the system by hundreds of watts per square metre. And on the other hand, during cooler days, cumulus form later in the day, cumulonimbus may not form at all, and there are fewer clouds. This increases the energy entering the system by hundreds of W/m2.
I bring this up to emphasize that the system is not applying an average throttle of e.g. 10 W/m2 over the average area where the throttle operates.
Instead, it is applying a much larger throttle, of a couple hundred watts/square metre, but it is only applying the throttle as and where it is needed in order to cool down local hot-spots, or to warm up local cold spots. As a result, the averages are misleading.
The final reason that it is important to understand that the albedo changes are HOURLY changes, not monthly average changes, is that what rules the system are instantaneous conditions controlling cloud emergence, not average conditions. Clouds do not form based on how much forcing there is, whether the forcing is from solar or CO2 or volcanoes. They form only when the temperatures are high enough.
And this means that things won’t change much if the forcing changes … because the cloud emergence thresholds are temperature-based, and not forcing-based.
I hold that this immediate response is the main reason that it is so hard to find e.g. a solar signal in the temperature record—because the thermoregulation is temperature based, not forcing based, and thus operates regardless of changes in forcing.
This is also the reason that volcanoes make so little difference in the global temperature—because the system responds immediately to cooling temperatures by reducing albedo, opening the thermostatically controlled-throttle to allow the entry of hundreds of extra W/m2 to counteract the drop in temperature.
There is plenty more to mine from the CERES dataset, and although I’ve mined some of it, I still haven’t done lots of things with it—an analysis of the efficiency of the climate heat engine, for example. However, I think this clear demonstration of the existence of a temperature-regulated throttle controlling the amount of energy entering the climate system is important enough to merit a post on its own.
Best regards to all on a sunny December day,
w.
Gerald Kelleher says: @ur momisugly December 29, 2013 at 12:55 pm
>>>>>>>
My dear Gail
http://www.newgrange.com/winter_solstice.htm
The neolithic alignments of Stonehenge and Newgrange which are over 5200 years old are 20% through a precessional cycle yet still happen on the Dec/June Solstice so it should give you an indication of how flawed axial precession is as a conception.It is time to revisit all the conceptual astronomical inputs which define climate and explain the seasons otherwise all these assertions come off as pretension and bluffing like the following graphics are and on which you base your assertions
https://upload.wikimedia.org/wikipedia/commons/6/64/Earth_axial_precession.svg
If the fact that the ancient alignments are still valid and not enough for you to actually look at a climate spectrum which relies heavily on using axial inclination then good luck to you.Forget Milankovitch cycles,it belongs to a different era along with wishful thinking of summer/winter climate when the generalized rules extend specifically to an equatorial of polar climate – global terms and not hemispherical ones.
Of course it happens that when things like ‘no tilt/no seasons’ or axial precession as it is presently understood is so fixed in your head from your schooldays that no argument ,everything from the neolithic alignments to actually imaging, can alter your point of view but perhaps some others will catch a glimpse of something new and much better for terrestrial sciences including climate research.
This is probably going to expose my abysmal ignorance of climate but: Did the southern hemisphere go through an ice age with sheets of ice or was the ice age a northern hemisphere phenomenon?
Bill H says:
December 29, 2013 at 12:39 pm
So are there not *two* – 2 ways to throttling devices or negative feedback loops
1) cloud formation in the tropics.
2) heat rejection at the poles
???
Excellent summary observation and links. Thanks muchly.
BTW, you can save words and eliminate an awkward redundancy by just using “most” instead of “most amount of”. If you prefer the extra wordcount, try “largest amount of”.
A little OT but about ocean circulation and heat…
Eels and the AMO
http://www.bbc.co.uk/news/science-environment-25505612
Apparently the low eel numbers in Europe in recent years are due to disruption of the gulf stream currents carrying the elvers from the Sargasso sea.
Is this a sign that the AMO i.e. the gulf stream is changing, to the cyclic AMO downswing?
I like Willis’ masterful use of phase space. Finding pairs of carefully chosen climate parameters and plotting them against eachother portrays a phase space, an illuminating technique.
Phase spaces are good for showing chaotic-nonlinear attractors. If a phase space reveals a cool unexpected shape its likely there is some kind of attractor involved.
Apply for a grant, to do an exhaustive exhaust analysis. Call it “Banana in my Tailpipe”.
Throttle is not an incorrect term. But I still think regulator is more descriptive.
Nag-dabbit. Stonehenge. One of those things that skritched in the back of the mind, but never got brought forward. Every time I saw a clip of the solstice line-up of the sunlight on the exact right gap in the stones, I sorta wondered, “Still?”, but never worked back to the (obviously flawed) assumptions that were causing my surprise.
So. Precession is disproved by Stonehenge!! Glorious. Love it. A neolithic Davidic slingshot stone to the forehead of the modern Science Goliath!
What say you, Leif?
sophocles (December 28, 2013 at 11:30 pm) “The `throttle’ being over the tropical oceans is no big surprise. Is there any correlation with ocean currents? ie; could they assist with sensitivity, forcing, etc?”
Here’s a paper about that: http://www.esrl.noaa.gov/psd/people/dezheng.sun/dspapers/science96/science-f.pdf “In this article we propose an alternative thermostat for the SST in the tropical Pacific Ocean: the dynamic coupling between the atmosphere and the ocean.”
Basically the SST difference creates a surface wind which creates a current which limits the SST. The apply it to two large areas, the east and west Pacific so it is a large scale throttle not small scale like the thread is about. But it also helps explain why the strong positive feedbacks and momentum that characterize the El Nino (see http://bobtisdale.wordpress.com/2013/10/22/enso-basics-westerly-wind-bursts-initiate-an-el-nino/ ) could also override the thermostat suggested in the Sun/Liu paper.
Box of Rocks says:
December 29, 2013 at 3:23 pm
Both of the throttles (one throttle and one choke) are controlled by an outside influence, the sun. Both involve water in its various forms. One controls inflow and the other out flow. Pressure and temperature differential are what appear to make them work.
It would not surprise me if the old two cylinder engine that my grandfather relied on for decades because it was reliable and constant are much like what WIllis is describing. The input is controlled by clouds and water vapor. The oceanic flows are the constant and their speeds regulate how fast the energy is transferred from the equator to the poles. The Ice is a buffer slowing LWIR out flow. As sea ice increases the LWIR decreases. As sea ice Decreases LWIR increases. Open sea water and wind should drive this fairly well.
SO basically put, water is most certainly the controlling factor in it various forms. CO2 not so much as this trace gas can not overwhelm the thermostats discussed and from the geological record of very high CO2 levels in earths history when both glaciation and warm periods were present it would lend credence to the hypothesis.
— Peter Miller says:
December 29, 2013 at 1:41 am
Perhaps what is so amazing is the stability of the Earth’s climate over the past 500 million years with the occasional near extinction event obviously excluded.
There obviously has to be some kind of self-regulation mechanism for our planet’s temperature and climate.
After all:
1. We have been steadily moving further away from the Sun.–
It’s been measured to be 15 cm per year.
So 1.5 meters decade. 1.5 million meter in 10 million- or 1500 km.
And in 500 million that’s is 75,000 km.
Assuming measured accurately and a constant rate over 500 million years.
“The current value stands at 149,597,870.696 kilometres.
Having such a precise yardstick allowed Russian dynamicists Gregoriy A. Krasinsky and Victor A. Brumberg to calculate, in 2004, that the sun and Earth are gradually moving apart. It’s not much – just 15 cm per year – but since that’s 100 times greater than the measurement error, something must really be pushing Earth outward.”
http://www.newscientist.com/article/dn17228-why-is-the-earth-moving-away-from-the-sun.html#.UsDcZPtFbzY
And if extend 5 billion years [which due many forces from large impactors over such
time period] is probably a bad idea. But anyhow: 750,000 km
So 149.5 million distance vs change of .75 million over 5 billion.
Let’s go to: 4. Our planet has an elliptical orbit.
Which varies by 147.1 million km to 152.1
http://nssdc.gsfc.nasa.gov/planetary/factsheet/
So each we changing the distance to by 3.75 times more distance
than earth *may* have move outwards in duration of 5 billion years.
So this variation of 5 million km does have significant effect upon
the amount energy reaching earth. According wiki:
“The actual direct solar irradiance at the top of the atmosphere fluctuates by about 6.9% during a year (from 1.412 kW/m² in early January to 1.321 kW/m² in early July) due to the Earth’s varying distance from the Sun”
http://en.wikipedia.org/wiki/Solar_constant
So have average of 1361 watts, then due to distance it varies from 1321 to 1412 watts
per square meter.
And sun’s output and perhaps more important different amounts of say, it’s UV spectrum,
effects this average of 1361 watts.
-2. The Sun has been steadily increasing its energy output. Also, we can measure the change in energy output over the known 11 year cycle, but we do not know if there are more much longer cycles.-
According to wiki, same article:
“Solar output is nearly, but not quite, constant. Variations in total solar irradiance were too small to detect with technology available before the satellite era. Total solar output is now measured as varying (over the last three 11-year sunspot cycles) by approximately 0.1%; see solar variation for details”
So 0.1% of 1000 watts is 1 watt per square meter. But according pseudoscience of AGW,
1 watts per square meter is important. And if one has 1000 median, 0.1% variation is 999 to 1001 watts. Or if at closest of 1412 watts, it’s 1410.5 to 1413.4.
So averaged swing of 1413.4 to 1319.68. A 93.7 watts per square range of variation of the sun
light reaching top of Earth’s atmosphere.
So a 90 watts per square meter range should large amount to the religious believers overly concerned about tenths of degrees in average temperatures.
But I am sure whether sun has warmed significantly in last, oh say 500 million years. So I don’t know for example whether there has 1% increase or decrease in solar flux during this period.
I seems plausible that there has been such levels of variation, but from indirect historical proxy records measuring the sun to accuracy better than 10 watts plus or minus doesn’t seem possible.
I don’t even have confident that present satellite measurement is within error of 1 watt plus or minus.
If we to do some exploration of the Moon, then I think more accurate proxies could achieved.
One because moon isn’t filter through atmosphere with level of dust, that not sure we have yet measured accurately. Plus knowing Earth dust levels accurately over last 500 million years seems highly implausible. Someone please give the reference to such a important and laborious work.
Second the Moon surface could describe as very static compared Earth- the 1960’s footprints
are probably still fairly pristine- whether they will last 10 times longer than age of the Pyramids
is debatable, though it seems their chance of them being discernible in 100,000 years, very much unlike anything exposed on the surface of Earth for such time periods. Or Lucy’s footprints were buried by volcanic ash within a short period of time.
So given enough study, utilization of science, of the kind which are employed on Earth, were to be done on the Moon, it seem one could get a fairly accurate record of the Sun from the Moon over periods of hundreds of millions or billions of years.
-3. The continents move around the face of our planet having a long term impact on climate.-
Yes. There are why we has been in a Ice Box climate for 10+ millions years. The absurdity of thinking Earth is warmest it’s ever been is pathetic. In this ice box climate, we are about 10 C cooler in terms of average global temperature. Or having permanent polar ice caps is not been Earth’s “normal” climatic conditions. And idea this could change within a thousand years
is indication of no understanding of Earth’s climate.
Rhoda R says: December 29, 2013 at 3:02 pm
Did the southern hemisphere go through an ice age with sheets of ice or was the ice age a northern hemisphere phenomenon?
Mainly northern hemisphere … map here …. some in South America (wiki below)
http://earth.rice.edu/mtpe/cryo/cryosphere/topics/ice_age.html
http://en.wikipedia.org/wiki/Last_Glacial_Maximum
Seems plausible but what is the explanation for the 500 year drop in temperature and 400mm drop in sea level from 1100AD?
Gerald Kelleher
I understand that one orbit of the earth around sun is equivilent to another rotation of the Earth on its axis this is important if we are calculating the days of the year, the fact is though I think that the earth is still inclined with respect to the sun and the axis of this inclination is at the equator when the earth completes one orbit of the sun.
You really have very, very little “land” in the Southern Hemisphere compared to equal latitudes up in the north. Chicago = 42 north, New York = 40.6, Toronto = 43.7, Cleveland = 41.4, Pittsburgh = 40.4, Albany = 42.6. Those cities, and all of the land between there extents, were covered with thousands of feet of solid ice for thousands of years. But little ice went much further south – about the bottom of Illinois (Cairo) at latitude 37 north.
Contrast this with the Cape Horn (latitude 56 south) -> That’s the closest piece of land to the Antarctica. The very first piece that could be ice-covered. South of there – there is nothing but water (and the ice shelves of Antarctica, the sea ice around Antarctica, and the 14.0 million km^2 ice-covered rock of Antarctica). So, glacier ice covering anything in the south could only come down from the Andes mountains (like the Alpine glaciers extend down those mountains). They’d cover areas down from the Andes, but much less than the continent wide masses found up north. 40 south latitude cuts Argentina about in half, so the south half of that country might become ice-covered if the southern hemisphere were a mirror image of the north glaciers.
Africa (Cape of Good Hope = 34 south) is another example of geography preventing massive glaciers from “creeping up” onto land. The African land masses start at 34 south, but up north, the glacier masses have ended at 37 north! You’d likely to have only glaciers coming from the very few south African mountains over there.
If a “glacier mass” could extend north from Antarctica, there would be little evidence (compared to millions of years of debris dropping from icebergs sheared off of Antarctica, so we’d see no evidence even with sub-sea drilling cores. If you found glacier-dropped residue, how do you tell what dropped it? When it dropped maybe, but where did it come from?
Re Gerald Kelleher says: December 29, 2013 at 2:52 pm
This is re Newgrange, not Stonehenge, but there is similar information available for it, including how precession calculations helped pinpoint its dating to about 4200 BP.
Once a year, at the winter solstice, the rising sun shines directly along the long passage into the chamber for about 17 minutes and illuminates the chamber floor.[5] Professor M. J. O’Kelly was the first person in modern times to observe this event on 21 December 1967.[28] The sun enters the passage through a specially contrived opening, known as a roofbox, directly above the main entrance. Although solar alignments are not uncommon among passage graves, Newgrange is one of few to contain the additional roofbox feature; (Cairn G at Carrowkeel Megalithic Cemetery is another, and it has been suggested that one can be found at Bryn Celli Ddu.[29]). The alignment is such that although the roofbox is above the passage entrance, the light hits the floor of the inner chamber. Today the first light enters about four minutes after sunrise, but calculations based on the precession of the Earth show that 5,000 years ago first light would have entered exactly at sunrise.
http://en.wikipedia.org/wiki/Newgrange
StoneHenge details: http://www.scribd.com/doc/38554228/Gordon-R-Freeman-and-Phyllis-J-Freeman-Stonehenge-Archeology
“Maybe I’m just to simplistic but a plugged exhaust on my car sure makes it overheat.”
Bill
Ignorant , not simplistic. A car has an internal combustion engine, not a Carnot heat engine.
“Add to this the fact the molecular weight of CO2 does not allow for it to be well mixed and thus at earths surface it is greater. ”
Read up on how gas diffusion works before make such bold statements. Even in a closed container with no air currents CO2 will be well mixed in under 24h.
phlogiston says:
I like Willis’ masterful use of phase space. Finding pairs of carefully chosen climate parameters and plotting them against each other portrays a phase space, an illuminating technique.
===
You cannot (usually) see the phase relationship if you remove the time element from a time series. You need to link the points in order not just throw up a scatter plot of dust.
A scatter plot can reveal certain things but looses most of the phase relationship information.
You are correct that phase is key to understanding how a system behaves. It is almost contradictory to remove the time element when investigating time series data. You certainly risk missing much of the information contained in the data if you remove a key part of it.
Brian H
You are truly unfortunate,precession goes from a long term axial trait to a long term orbital feature so your response that I am ‘disproving’ precession is the usual dismaying one.What you see as East to West precession of Uranus is actually the surface rotation of the planet to the central Sun just as the Earth,traveling around its orbital circumference,turns all locations of the Earth once to the Sun where the polar coordinates act like a beacon for that surface rotation.It is the only way to even discuss the polar day/night cycle and the seasons at lower latitudes where the two surface rotations combine.
http://londonastronomer.files.wordpress.com/2013/01/uranus_2001-2007.jpg
I am mindful that this is modifying the original proposals of ‘no tilt/no seasons’ for contemporary purposes as well as the explanation for the precession of the equinoxes along with appreciation of the exquisite astronomical monuments which still retain their alignments. In this era where people are screaming the sky is falling,it is so,so difficult to get people to widen their perspectives even when they have these amazing images in front of them which should draw attention to the necessary modifications and then draw new conclusions .
Markx
Have you any understanding of those images of Uranus and what looks like axial precession but really isn’t ?.
Newgrange and Stonehenge are separated by 1000 years or roughly 5% of a precessional cycle yet both maintain a fix on the June/December Solstices. If axial precession was valid,either one or the other monuments would lose its alignment as the 5% difference translates into an 18 degree difference however these points are truly secondary to actual images of the single surface rotation to the central Sun aside from and in addition to daily rotation that the Earth has and clearly visible in those sequence of images of Uranus. I truly admire what our ancestors did in antiquity so these monuments are quite important astronomically but what can be said for this era who simply will look for an escape rather than take a wider view of the matter thereby arrive at the same conclusions.
Axial inclination is required to define a climate spectrum between 0 degrees and 90 degrees rather than a dynamic to explain the seasons.The tendency is to explain the seasons by way of the Earth tilting towards and away from the Sun or some variant of that instead of looking at the polar day/night cycle and concentrating on what causes an observer at the South pole to experience one single night cycle of roughly 6 months of daylight followed by another 6 months of darkness. It is this and this alone which draws attention to the motion of the polar coordinates over the year and why axial precession as it is presently understood has to give.
Some thoughts on albedo
Great effort Willis!
Of the 0.3 albedo or reflectivity, about 0.22 is due to clouds and 0.08 is due to the surface. Oceans and water tend to be under 0.04 so there is a massive increase where clouds are present. Clouds tend to run 0.4 to 0.8 albedo when present, some more some less. Fresh snow tends to have similar albedo but drops as it ages and as it turns to ice it gets lower. Dirty snow is also lower.
Most land mass is in the NH but the difference in incoming solar insolation due to orbit occurs in the SH. The presence of much more snow during glaciation provides a short circuit to cloud effects -if it happens in a region where there is a thermostat effect.
Another factor is that cloud albedo varies. Some clouds have higher albedo than others and that seems to be associated with particulate size. How clouds are formed seems to be a factor – enter the cosmic ray influence possibility. Hence, not only the surface area of clouds affect albedo but also the reflectivity has an effect.
Finally, clouds do have a warming effect factor. If one does not take into account that the tropics clouds are daily cyclical beasts powered by sunlight, one can be lead to the error that increases in cloud cover will also lead to blocking of more radiated energy from the surface and tend to cancel out. Of course clouds formed and dissipated during times of insolation that are not around for night time surface radiation blocking have far less of this. Actual changes to the cloud’s albedo doesn’t factor in to this either.
Marx – Thanks for the information. I appreciate it.