A short primer on global energy flows, for the twitter deniers

Energy balancing when no forcing

There have been two or three people on the climate denial conversation on Twitter who cannot conceptualise global energy flows. Remember, almost all the deniers in this particular conversation are greenhouse effect deniers who don't "believe" physics and chemistry. Nonetheless they've discovered a wonky diagram in the deniosphere somewhere and have asked how it works. The short answer is, it doesn't. Not the way it's portrayed in their diagram.

Dr Kevin Trenberth has kindly allowed me to publish this updated global energy flow schematic, which is about to be published. (I'll post the doi when it is available.) Here it is, with an explanation below:

Willis Eschenbach wonders about CERES

Ceres circa 235 - 250 CE
Louvre: Borghese Collection; 
purchase, 1807

Wondering Willis Eschenbach is wondering about CERES (archived here, latest update here).  He's written quite a few articles about CERES data at WUWT lately.  I'm wondering if he's bothered to read anything about the data before wondering.  (I'm guessing he hasn't read too many scientific papers on the subject either, because it's not his way.)

For example, the CERES website has data quality summaries, such as this one for top of atmosphere data.  The paper states it "represents the minimum information needed by scientists for appropriate and successful use of the data product".



Today Willis wonders about outgoing longwave and reflected shortwave irradiance:

Now, there are several very curious aspects to this figure. The first and most surprising issue is that the hemispheric values for shortwave, and also the hemispheric values for longwave, are nearly identical from hemisphere to hemisphere. Why should that be so? There is much more ocean in the southern hemisphere, for example. There is solid land at the South Pole rather than ocean. In addition, the underlying surface albedos of the two hemispheres are quite different, by about 4 watts per square metre. Also, the southern hemisphere gets more sunlight than the northern hemisphere, because the earth’s orbit is elliptical.

So given all these differences … why should the longwave and shortwave in the two hemispheres be the same?

Willis answers his own question by writing this:

Given the myriad differences between the northern and southern hemispheres, my explanation of this amazing stability is that a) the temperature of the planet is regulated by a variety of threshold-based processes, and b) the set-point of that regulation is controlled by globally consistent values for the physics of wind, water, and cloud formation.

Now, there certainly may be some other explanation for this amazing stability and symmetry of the climate despite the large differences in the geometry and composition of the two hemispheres. That’s my explanation. If you have a better one … bring it on.

One can only guess what Willis means in his first paragraph above.  He's probably talking about his thunderstorm thermostat hypothesis, but it's pretty well gobbledegook. Especially his bit about "the set-point of that regulation is controlled by globally consistent values for the physics of wind, water, and cloud formation".  Never mind his silly "set point" notion - which is contradicted by paleo records (glacials and interglacials). What about his "Globally consistent values for the physics"? Does he mean that the behaviour of wind, water and cloud formation is consistent with known physics? That's a bit trite, surely.  Or is he trying to say something else. Who knows.

Anyway, I'm not so daft as to try to analyse or even interpret the TOA data from CERES.  One look at the data quality summary and I know I'm quite out of my depth.  It would take me longer than the time I have to start to come to grips with it all.  However, I did take a peek at the charts on the CERES website.  Below, for example, is an animation of the change in TOA net flux (all sky) over a climate year by latitude.

I've got to say there look to be differences between the net flux at different latitudes over the year.  However that's not broken down into longwave and shortwave fluxes.  Even so, if there is a difference then at least one of shortwave or longwave (or incoming solar) must also be different.  You can see the shortwave and longwave variations by latitude here. Click on one of the charts to view month by month as a slide show.

Before I get to Willis' specific question, here are a couple more diagrams, showing the TOA net flux (all sky) on a regional basis. First for February (click to enlarge):

Next for July:

There's another NASA web page that has an animation of the net radiation over the globe from July 2006 to October 2013. It's mesmerising.  As stated on the website, "averaged over the year, there is a net energy surplus at the equator and a net energy deficit at the poles. This equator-versus-pole energy imbalance is the fundamental driver of atmospheric and oceanic circulation."

Here is a chart showing the annual solar insolation over the year by latitude.

The total energy received each day at the top of the atmosphere depends on latitude. The highest daily amounts of incoming energy (pale pink) occur at high latitudes in summer, when days are long, rather than at the equator. In winter, some polar latitudes receive no light at all (black). The Southern Hemisphere receives more energy during December (southern summer) than the Northern Hemisphere does in June (northern summer) because Earth’s orbit is not a perfect circle and Earth is slightly closer to the Sun during that part of its orbit. Total energy received ranges from 0 (during polar winter) to about 50 (during polar summer) megajoules per square meter per day.
Source: NASA

The page from which the above diagram came discusses the radiation budget in terms of incoming, reflected and net radiation.  It also uses one of Willis' favourite analogies (which I think he thinks he invented), the heat engine.  It's part of a series of articles at NASA's Earth Observatory website, on the topic of Climate and Earth’s Energy Budget.  It would pay for anyone taken in by Wondering Willis to read it.  Willis might learn something himself, if he chose to.

How Wondering Willis mucked up somewhere

Now back to Willis' question.  He asked why longwave and shortwave are the same for each hemisphere.

I came across a paper by Voigt et al (2013), which says that both hemispheres reflect nearly the same amount of short wave irradiance but that the long wave irradiance is quite different between the two hemispheres.  So it looks as if Willis has done something wrong in his analysis.  He got the shortwave bit right (at least insofar as the two hemispheres are almost identical), but didn't pick up the difference in longwave irradiance.  Here is the abstract from Voigt13, which probably raises more questions than it answers (my paras):

While the concentration of landmasses and atmospheric aerosols on the Northern Hemisphere suggests that the Northern Hemisphere is brighter than the Southern Hemisphere, satellite measurements of top-of-atmosphere irradiances found that both hemispheres reflect nearly the same amount of shortwave irradiance.

Here, the authors document that the most precise and accurate observation, the energy balanced and filled dataset of the Clouds and the Earth’s Radiant Energy System covering the period 2000–10, measures an absolute hemispheric difference in reflected shortwave irradiance of 0.1 W m−2.

In contrast, the longwave irradiance of the two hemispheres differs by more than 1 W m−2, indicating that the observed climate system exhibits hemispheric symmetry in reflected shortwave irradiance but not in longwave irradiance.

The authors devise a variety of methods to estimate the spatial degrees of freedom of the time-mean reflected shortwave irradiance. These are used to show that the hemispheric symmetry in reflected shortwave irradiance is a nontrivial property of the Earth system in the sense that most partitionings of Earth into two random halves do not exhibit hemispheric symmetry in reflected shortwave irradiance.

Climate models generally do not reproduce the observed hemispheric symmetry, which the authors interpret as further evidence that the symmetry is nontrivial. While the authors cannot rule out that the observed hemispheric symmetry in reflected shortwave irradiance is accidental, their results motivate a search for mechanisms that minimize hemispheric differences in reflected shortwave irradiance and planetary albedo.

Below is Figure 1 from Voigt13 showing the hemispheric difference for the 12 month running mean of reflected short wave and outgoing long wave radiation.  Notice the different y axis on each. (Click to enlarge.)

Voigt, Aiko, Bjorn Stevens, Jürgen Bader, Thorsten Mauritsen, 2013: The Observed Hemispheric Symmetry in Reflected Shortwave Irradiance. J. Climate, 26, 468–477.
doi: http://dx.doi.org/10.1175/JCLI-D-12-00132.1

From the WUWT comments

There are quite a lot of comments. I haven't read them all but so far all but one seem to assume that Willis is correct and there is something "wrong" with the data or there is an explanation for Willis' contention that there is no difference in outgoing longwave or reflected shortwave irradiance between the two hemispheres. (Archived here, latest update here.)

AlecM talks about CO2 as a "working fluid" and says:

January 7, 2014 at 12:04 am
A remarkable study. The explanation s that there is a very stable set of control systems in the atmosphere which use CO2 as the working fluid thus reducing CO2-AGW to near zero.

The other issue is that the ‘forcing’, black body real surface energy flux and ‘back radiation’ ideas in Climate Alchemy are bad physics and must to be junked before the theory can advance.

AndyG55 refers to Willis' notion of a "regulator" of his thunderstorm thermostat hypothesis says:

January 7, 2014 at 1:46 am
Willis, could it be something to do with atmospheric pressure being the regulator?

AndyG55 says earth needs more incoming than outgoing energy for it to function (my bold italics):

January 7, 2014 at 2:04 am
I have to say I would be amazed if there was a balance of zero.

Plant life consumes energy, and the biosphere is growing.

Every movement of any tree or structure by wind causes changes within that tree or structure that are locked there for its life. The whole of Earth is constantly being eroded by energy changes, rocks crack, metals corrode. How much energy is dissipated in a large wave? Where does it go to?

No, here MUST be more energy coming in than going out for the Earth to function.

tty says the opposite to AndyG55, that there's more energy leaving than entering:

January 7, 2014 at 3:09 am
Actually slightly more energy must be going out than coming in, since geothermal heat is continuously being created by radioactivity. There may also be some residual heat from the early stage of planet formation, plus a little bit being liberated by tidal braking of the Earth’s rotation. In all about 0.1 wm-2.

There was someone posting stuff that no-one could follow (me included), which probably prompted this comment by jaffa, who says:

January 7, 2014 at 5:31 am
It’s like I’m stuck inside David Icke’s head.

Ross McKitrick says:

January 7, 2014 at 5:49 am
Willis says: “Now, there certainly may be some other explanation for this amazing stability and symmetry of the climate despite the large differences in the geometry and composition of the two hemispheres. That’s my explanation. If you have a better one … bring it on.”

Shouldn’t be too hard. All anybody has to do is solve the equations of motion of two nonlinear fluid systems coupled on a rotating sphere and subject to differential heating, turbulent mixing, random phase changes, low frequency inputs on unknown time scales and radiative transfer processes across the spectrum. I keep hearing that this is “simple physics”.

Andres Valencia is the only person I've come across in the discussion, who questions Willis' conclusions and says:

January 7, 2014 at 7:18 am
Thanks Willis. Good questions.
Why should the longwave and shortwave in the two hemispheres be the same?
Are they the same?
I’ll keep tuned to your inquire.

Willis Eschenbach himself gets more and more irate with a particular commenter over the course of the discussion, at one point writing (excerpt)

January 7, 2014 at 9:01 am
...EITHER PROVIDE PROOF OF YOUR FALSE CLAIMS, OR STAND CONVICTED OF BEING A HILARIOUSLY CHILDISH LYING SACK OF PORCINE EXCREMENT!
Is that clear enough for you, you libelous scumbag?

w.

That's not very nice, Willis, is it.