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.
Throwing a high-five attcha, Willis! Fantastic stuff.
Living in South Carolina for many years, the summer cloud behavior was just as Willis describes. Clouds progressively gathered, and rain came just as we got off work every day. It is also noteworthy that the hottest times are when there is a drought because not enough water to make those clouds (or cooling rain).
There is an interesting paper by a high school student Meredith Croke at
http://journals.ametsoc.org/doi/full/10.1175/1520-0442(1999)012%3C2128%3ARCCCAW%3E2.0.CO%3B2
that might be relevant to these discussions.
Bernie
Gerald Kelleher says: December 30, 2013 at 12:11 am
Markx…..Have you any understanding of those images of Uranus and what looks like axial precession but really isn’t ?.
Frankly, Gerald, I must admit, I’m baffled, and the more I read and re-read the above posts on this, the less I understand.
I now have no idea whatsoever in regard to the point here. I’d ask you to enlighten me, but I fear the above-mentioned trend will only continue, and we are going way off topic.
I think I will leave it at this point.
Thanks and best regards,
Mark
Naw,I am going to leave it for somebody else to work out the details as the first reading would be plain enough. The use of Newgrange and Stonehenge Solstice alignments across their 1000 year separation would translate into an 18 degree difference if axial precession was valid so Newgrange would have lost its alignment by the time Stonehenge was being built if the following graphical description were true –
https://upload.wikimedia.org/wikipedia/commons/4/43/Earth_precession.svg
As Newgrange is already through 20% of a precessional cycle ,the alignment would be off by roughly 73 day from the original solstice 5200 years ago at this stage but it isn’t hence it is worthwhile to revisit planetary dynamics behind the daily and annual temperature fluctuations.
The real value of this approach is explaining the polar day/night cycle where it is not possible to rely on the inadequate ’tilt towards and away from the Sun’ explanations that have survived from the original work of Copernicus but it is not often people are focused on the orbital cause where a person standing on the South pole turns once to the central Sun as a component of the orbital behavior of the planet.
A parting note – the only satisfaction I get is the attempt to raise the standard of discussion rather than disproving ideas and I take no joy in watching people who made poor predictions get caught in the very weather conditions they said would cease.I was not disproving precession,the actual cause of that features is a hugely arduous task which is devoid of any company but as presently understood is highly disruptive to climate studies.
Feedback loops upon feedback loops …
So, a cooling globe begat an intense Negative PDO. The PDO begat a Rex of a Block. The Block begat a “hot spot” over CA. The “hot spot” begat Warmistas to call for the heads of “Denialists” (see today’s SJ Mercury page, the article about the drought).
I’m very looped now and have not had a single drop to drink!
Happy New Year.
Gerald Kelleher says:
December 29, 2013 at 12:35 pm
My friend, I fear that is totally incomprehensible. The Equator doesn’t even have a surface area, it is an imaginary line.
The maximum solar energy hitting the planet is at the perigee, and has nothing to do with the ecliptic path.
And as to whether the poles point away or towards the sun, why does it make no sense to say something so obviously true as that?
Sorry, but I can’t follow your thoughts.
w.
So Willis, if I tilt my head over at 23 1/2 degrees, a near sphere will look different ?? Dang ! They always look the same to me. Maybe Gerald has discovered something new.
george e. smith says:
December 30, 2013 at 11:35 pm
Thanks, george. What I said was that if you tilt your head over at 23 1/2 degrees, the crown of your head will be pointing either towards or away from the sun … but I said nothing about whether a “near sphere will look different”, whatever that might mean.
w.
Willis:
The temperature is reading from space. The satellite measures the actual temperature of the surface without that temperature also being blocked by the clouds that also reflect the incoming solar irradiance from getting to the surface? I think the answer is yes they can, but how do the satellites read the surface temperature through the clouds, and how do we know that they are not also reading the reflected energy too? I assume that the warm areas have increased albedo, and so the satellites perform some math to subtract the amount that’s being blocked by the albedo increase. It’d be interesting to know the surface temperature readings vs the reflected energy –and perhaps that is what indeed is being measured.
I hope this above comment by me was a softball question. Tuthfully I do not actually know how the satellites calculate the surface temperature through the clouds.
Willis
The Equator represents not only a line on the Earth,it represents the maximum circumference in tandem with the maximum rotational speed of the Earth – there is nothing imaginary about it. The polar coordinates represent points on the Earth where daily rotational influences are zero hence the issue comes up as to what causes a person standing on the poles to experience 6 months of daylight followed by 6 months of darkness -there is nothing imaginary about these points either.
The maximum energy entering the Earth regardless of its orbital position is always along the line of the ecliptic and at right angles to the circle of illumination like so –
http://www.msss.com/mars_images/moc/2003/05/22/earth_americas250.jpg
The Earth doesn’t tilt towards and away from the Sun as a means to explain annual temperature fluctuations at different latitudes insofar as this is loading daily rotation with an action it does have,however.It has a motion than looks like axial precession when seen from a distance just as those images of Uranus demonstrate but what it is really happening is that all locations on Earth turn once to the central Sun and the polar coordinates are merely a window or beacon into that single surface rotation which runs East to West on Uranus –
http://londonastronomer.files.wordpress.com/2013/01/uranus_2001-2007.jpg
Go ahead,try the same motion with the Earth and you will get a better idea why temperatures fluctuate across an orbital period as opposed to the Equator tilting towards and away from the Sun even though people should know that the planet maintains the same daily orientation in space just as Uranus does. –
http://www.msss.com/mars_images/moc/2003/05/22/earth_americas250.jpg
Oops bad typo –
“The Earth doesn’t tilt towards and away from the Sun as a means to explain annual temperature fluctuations at different latitudes insofar as this is loading daily rotation with an action it does have”
That should read,the Earth doesn’t tilt towards and away from the Sun as the tilting action doesn’t happen,what happens is that all locations on Earth turn once to the central Sun along the line of the ecliptic where the axis is defined running North to South and in line with the circle of illumination –
http://www.msss.com/mars_images/moc/2003/05/22/earth_americas250.jpg
Of course unfortunate people can manage to get the circle of illumination to tilt as demonstrated by the Wikipedia article but it should strike the eyes and the mind as hideous –
Expecting students to swallow that rubbish is dismaying when relatively simply motions seen in those images of Uranus where the planet turn South to North due to daily rotation and East to West as a component of orbital motion do the job right .
Sorry for the poor proofreading.
Mario Lento says:
December 31, 2013 at 12:43 am
If you mean the temperatures I’m using in this analysis, no, these are from surface measurements. The satellite is measuring up- and down-welling long- and short-wave radiation.
w.
George Smith
Want to teach students how this works then take a broom handle to represent the constant axial orientation of the Earth as it travels around the Sun and any object to represent the Sun.
Point the broom handle at any external point and walk/orbit around the central object Sun where the line of your body represents the ecliptic axis .The broom handle represents the Lat/Long system at 23 1/2 degrees to the ecliptic axis in the actual image while the line of your body represents the North/South axis of the ecliptic axis while walking/orbiting along the plane of the Earth’s motion through space and around the Sun.
http://www.msss.com/mars_images/moc/2003/05/22/earth_americas250.jpg
In order to keep the broom handle fixed to the same external point (representing fixed orientation towards Polaris),the student discovers that as they walk/orbit the central object,all points in their body face the central object/Sun once across an orbital circuit and this is what you see in those images of Uranus –
http://londonastronomer.files.wordpress.com/2013/01/uranus_2001-2007.jpg
I am in danger of overselling this but the ’tilting’ Earth is a hard indoctrination to break.
Gerald Kelleher says:
December 31, 2013 at 12:48 am
Gerald, if the Equator’s not imaginary, then it must be real. Do you have any photographs of it?
Seriously, though, I’m not at all clear what your point is. Yes, the axis of the earth doesn’t tilt back and forth … so what? And what does it have to do with the thermostatic throttle?
At present, you seem to be fighting a fight against someone other than myself. I don’t care whether you use a geostationary frame of reference, or a heliocentric frame of reference. Based on one, the earth’s has no tilt and that never changes (except for precession). Based on the other frame of reference, the poles tilt so that the north pole is alternately visible and not visible from the sun. Both frames of reference have their uses, you can pick one or the other based on your needs.
But so what? What does this have to do with the subject under discussion?
Sorry to be so blunt, but truly … what does this have to do with me or my post?
Thanks,
w.
Gerald Kelleher says:
December 31, 2013 at 12:48 am
Gerald, that is totally unclear. Your link doesn’t help. You say the maximum energy is “along the line” of the ecliptic … but the ecliptic is a circle. And you say the max energy is “at right angles to the circle of illumination” … what does that mean? It sounds like it means that the energy is at a maximum where the sun is shining … but if so, while true, that means nothing.
In any case, the problem with your underlying assertion is that the total energy entering the Earth depends, not on the ecliptic, but on the distance from the earth to the sun. This is at a minimum in January and a maximum in July, with a difference (from memory) of about 28 W m-2 from max to min. The maximum energy enters the earth in January, at perigee (closest approach to the sun).
And perigee has nothing at all to do with either the ecliptic or the “circle of illumination”
w.
PS—Once again … what does this have to do with a tropical thermostat?
Your statement is this –
“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.”
This is incorrect,the stable maximum energy input ,regardless of where the Earth is in its orbit, is along the line of the ecliptic and this is why we have the seasonal temperature fluctuations across latitudes. This is literally explaining the seasons in a new and non aggressive way,whether it is accepted or not is a different matter.
If people wish to be experts in climate,a good start would be to revisit the cause of temperature fluctuations at different latitudes as the Earth orbits the Sun otherwise known as the seasons.
Willis
The total energy budget from solar radiation may have a minor fluctuation due to the variation in orbital distance from the Sun as a side issue however the maximum energy received on the surface is always dictated by the area of the surface which is turned to the Sun as a component of its orbital motion.
You can tell where the Earth is in its orbital position by the location of the polar coordinates to the circle of illumination and ecliptic axis as the North/South poles are turned to the Sun each year hence 6 months of darkness followed by 6 months of daylight –
http://www.msss.com/mars_images/moc/2003/05/22/earth_americas250.jpg
No point walking on eggshells here,if this community doesn’t wish to focus on the orbital day/night cycle and its cause,including the annual temperature fluctuations caused by that component of orbital motion then there is little I can do about that. The major factor for the seasonal fluctuations in temperatures is not the inclination to solar radiation but the length of time any given latitudes spends in solar radiation or the orbital shadow of the planet..
Gerald Kelleher says:
December 31, 2013 at 1:41 am
I think I see the problem. My statement referred to the annual average energy, while your statement refers to the instantaneous maximum energy. Your claim, which is true, is that the most energy at any instant is absorbed directly under the sun. This is true, but not material to the question of where to locate a regulatory mechanism.
My claim, however, relates to the long-term location of a regulatory mechanism. It is located somewhere around where the long-term average incoming energy is near the maximum.
w.
Gerald Kelleher says:
December 31, 2013 at 2:03 am
The cause of the day-night cycle? You think I should focus on the cause of the day-night cycle?
My friend, I have navigated across the Pacific using celestial navigation with a sextant. There is little you can teach me about the day-night cycle, or about how the sun moves through the sky.
Let me simplify your statement. Both the height of the sun above the horizon ( what you call “ inclination to solar radiation“) and the length of day (what you call “time any given latitudes spends in solar radiation”) affect the seasonal fluctuations in temperature.
However, both quantities are mathematically related, one can be calculated from the other, and both can be calculated for any given date and location on the planet.
So it is not correct to say that one is a “major factor” and the other is not. They are two facets of the same thing. Both are caused by the fact that the axis of the earth is not perpendicular to the plane of the ecliptic, which gives us seasons with varying solar elevations and day lengths … but again …
So what? What is it that you think we don’t understand about seasons with varying day lengths? And how does that affect the climate in other than the ways we all know about?
w.
Willis
The maximum solar energy received by a specific area of the Earth’s surface is defined by a line that runs at right angles to the North/South line which runs parallel to the circle of illumination in that image –
http://www.msss.com/mars_images/moc/2003/05/22/earth_americas250.jpg
As the Earth moves along the ecliptic plane it also turns once to the central Sun thereby changing the relationship between the length of time any given latitude spends in solar radiation or orbital darkness.The Earth does not tilt toward and away from the Sun or any variant on that theme,it has a separate surface rotation that is best understood in isolation at the North/South poles as the single day/night cycle experienced over a year.The guys stuck in the sea ice don’t have to worry about darkness setting in because the orbital position of the Earth has orientated the surface to the central Sun in such a way that their latitudes receive constant radiation from the Sun until around the Equinox when that polar latitude turns through the circle of illumination and into orbital night.
The idea of ‘axial precession’ is gone as it is disruptive to the perspective which recognizes two surface rotations to the central Sun instead of the single daily rotation that is presently recognized.The introduction of a second orbital surface rotation relieves the stress in loading daily rotation and its traits with so many causes and effects and especially what the degree of planetary inclination actually does. Precession exists of course but its 25900 year cycle goes to being a long term orbital trait rather than a long term axial one.
There is no need to taunt or insist that unless the polar day/night cycle and its cause is explained properly,all bets on climate research are off.
Willis
I am talking about the motions of the Earth,while you are giving geocentric descriptions of the motion of the Sun above the horizon and I am not going to be dragged into a discussion on putting words in my mouth.
A navigator would know that the 24 hour AM/PM system in tandem with the Lat/Long system assigns a maximum Equatorial speed of 1037.5 miles per hour so that the Earth turns once in a 24 hour cycle with all its effects such as daily temperature rises and falls which keep instep day in and day out.
The jokers in the late 17th century decided to model the motions of the Earth based on a rotating celestial sphere framework and insist that the Earth doesn’t turn once in 24 hours,ignore all the effects and experiences of one rotation in 24 hours and rig everything to suit the model for the Earth’s rotation in 23 hours 56 minutes 04 seconds.As a human being you should be appalled at the attempt to create an imbalance between rotations and 24 hour cycles insofar as even the cause of the daily temperature fluctuations are compromised as a fact but the fact is you are not and won’t be. So students have to suffer through mindnumbing ‘facts’ that belong in an asylum because people do not want to get their act straight in respect to the motions of the Earth –
” Multiplying the value in rad/s by Earth’s equatorial radius of 6,378,137 m (WGS84 ellipsoid) (factors of 2π radians needed by both cancel) yields an equatorial speed of 465.1 m/s, 1,674.4 km/h or 1,040.4 mi/h. Some sources state that Earth’s equatorial speed is slightly less, or 1,669.8 km/h. This is obtained by dividing Earth’s equatorial circumference by 24 hours. However, the use of only one circumference unwittingly implies only one rotation in inertial space,”
Some sources indeed !,the sprawling history of the Longitude problem and how watches and the 24 hour system mesh with the Lat/Long system dictate an Equatorial speed of 1669.8 km /h so giving the Earth’s Equator “two circumferences” can only come from the same type of people who can just as easily turn ‘global warming’ into ‘climate change’ when it suits.
The question still stands – the people on that stranded ship are close to the South pole where they experience a single day/night cycle over the course of a year.Before people mock their predicament perhaps they should look at our own where not even the lockstep between one rotation and all the effects within a 24 hour cycle are rejected and that is more than sad.
Gerald Kelleher said:
December 31, 2013 at 1:41 am
“If people wish to be experts in climate,a good start would be to revisit the cause of temperature fluctuations at different latitudes as the Earth orbits the Sun otherwise known as the seasons.”
At the extremes there is only one season, bloody cold(Dark or Light) at the poles and bloody hot(wet or dry) at the equator. The tropics have two seasons hot/wet and warm/dry. Only the middle of the temperate zones can claim to have four seasons! Where I live at 42% South we have three, freezing(damp), cold(wet) and warm (dry)! 😉
Out of interest, my town broke its cold temperature record and nearby the coldest temperature ever recorded for the State was equalled this year!
Willis writes “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.”
Had you thought about looking for a trend in the times of onset? There may not be enough satellite data for that though…
Scott Bennett
You got it backwards – at the Equator they experience no appreciable difference in daylight/darkness throughout the year while the poles the difference are extreme and from a separate cause to daily rotation,either way,the Earth’s surface must turn to the central Sun to cause the experience of the day/night cycle in both cases . Had the Earth a zero degree inclination,the surface conditions of the entire planet would be the same as experienced at the Equator presently in terms of no seasonal variations in daylight or darkness. It this respect an Equatorial climate can be considered to have one season or no season as it makes no difference in terms of daylight/darkness when you live on the Equator.
We use the term ‘climate’ in all sorts of ways from maritime climate to tropical climate to micro climate and no objections to that however for astronomical purposes the terms become more definite and only exist as an Equatorial climate (0 degree inclination) or a polar climate (90 degree inclination).
There is a bit of a mess going on with planetary dynamics ,although there is nothing exceptionally difficult in assigning cause and effect to each individual motion,there is no real move in that direction to clear up the mess up to and including what causes the temperatures to rise and fall within a 24 hour period.
I have said what I came to say and can’t bear having people put words in my mouth,after all,the dispute is as much about integrity in dealing with common material than scoring points of right and wrong.