Guest Post by Willis Eschenbach
I’ve been investigating one of my favorite datasets in the last few days, the CERES satellite-based top-of-atmosphere (TOA) radiation dataset. In particular, I’ve taken month-by-month global and hemispheric averages of the data. The dataset consists of observations of three variables—downwelling solar radiation, upwelling longwave (infrared) radiation, and upwelling shortwave radiation (reflected sunlight). From these I derive a further dataset. This is the top-of-atmosphere (TOA) imbalance. It is calculated as downwelling solar minus upwelling (reflected) solar minus upwelling longwave. That gives a fascinating look at the overall radiation picture.
I got to thinking about this because of a curious claim in a recent paper published in Nature Climate Change entitled Model-based evidence of deep-ocean heat uptake during surface-temperature hiatus periods (paywalled). I did love the whole concept of “model-based evidence”, but that wasn’t what caught my eye. It was this statement (emphasis mine):
There have been decades, such as 2000–2009, when the observed globally averaged surface-temperature time series shows little increase or even a slightly negative trend (a hiatus period). However, the observed energy imbalance at the top-of-atmosphere for this recent decade indicates that a net energy flux into the climate system of about 1 W m−2 (refs 2, 3) should be producing warming somewhere in the system (refs 4, 5). Here we analyse twenty-first-century climate-model simulations that maintain a consistent radiative imbalance at the top-of-atmosphere of about 1 W m−2 as observed for the past decade. [References are listed at the bottom of this post.]
Anyhow, here’s some news regarding that claim of a consistent TOA imbalance, from the CERES satellite dataset:
Figure 1. CERES satellite-measured top-of-atmosphere (TOA) radiation levels, starting in January 2001. Numbers on the horizontal axis are months. Shown are the solar energy entering the system (red line), solar energy leaving the system (dark blue line) and longwave (infrared) energy leaving the system (light blue line). The overall monthly imbalance at the TOA is shown at the bottom in purple. The 12-month running average for each variable is shown as a thin line. Curiously, the variations in upwelling longwave are about 6 months out of phase with the downwelling radiation. All radiation values are positive. TOA Imbalance is solar less reflected solar less outgoing longwave, i.e. inflow less outflow. Twelve-month averages vary too little for the changes to be visible at this scale.
Now, there are a number of things of interest in this chart. The first is the fact that while the seasonal variations are fairly large, tens of watts per square metre, the annual variations are so small. At this scale we can hardly see them. So let’s expand the scale, and take a more close-up look at just the variations in the overall TOA energy imbalance (purple line at bottom of Figure 1). Figure 2 shows that result.
Figure 2. Closeup of the overall energy imbalance. Horizontal scale is months. Narrow line shows running centered 12-month averages of the TOA imbalance data. All radiation values are positive. TOA Imbalance is solar less reflected solar less outgoing longwave, i.e. inflow less outflow.
Here, we can begin to see the small variations in the 12-month running average. However, the average itself is around five watts per square metre … not good. That much out of balance is not credible.
This shows the difference between precision and accuracy. You see that the measurements are obviously quite precise—the 12-month running average only varies by about three-quarters of a degree over the whole period.
However, in absolute terms they’re not that accurate, we know that because they don’t balance … and it’s very doubtful that the earth is out of balance by five watts per square metre. That’s a very large amount, it would be noticed.
Now, I’ve previously discussed how James Hansen deals with this problem. He says:
The precision achieved by the most advanced generation of radiation budget satellites is indicated by the planetary energy imbalance measured by the ongoing CERES (Clouds and the Earth’s Radiant Energy System) instrument (Loeb et al., 2009), which finds a measured 5-year-mean imbalance of 6.5 W/m2 (Loeb et al., 2009). Because this result is implausible, instrumentation calibration factors were introduced to reduce the imbalance to the imbalance suggested by climate models, 0.85 W/m2 (Loeb et al., 2009).
As a result, Hansen used the Levitus data rather than the CERES data to support the claims of a ~ one watt per square metre radiation imbalance. However, all is not lost. The precision of the CERES data very good. In Figure 2 we can see, for example, how one year’s TOA radiation imbalance is different from another. So let’s expand the scale once again, and take an even closer look at just the 12-month running averages, for all four of the radiation measurements shown in Figure 1.
Figure 3. An even closer look, this time at just the tiny variations in the 12-month running averages of the CERES data as shown in Figure 1. All radiation values are positive. TOA Imbalance is solar less reflected solar less outgoing longwave.
Now we’re getting somewhere.
The first thing I noticed is the precision of the measurements of the downwelling solar radiation (red line). As you might expect, the sun is quite stable, it doesn’t vary much compared to the variations in reflected solar and upwelling longwave radiation. And the observations reflect that faithfully. So it seems clear that their instruments for measuring radiation are quite precise.
Next, I noticed that the change in the imbalance (purple) is more related to the change in reflected solar (dark blue) than to the variations in upwelling longwave. I’ve highlighted the reflected solar (dark blue) in the graph above. This is confirmed by the correlation. The R^2 between TOA imbalance and reflected solar is 0.67; but between TOA imbalance and upwelling longwave, R^2 is only 0.07.
This seems like an important finding, that the imbalance is mostly albedo related, and that because of variation in the albedo, the variations in the reflected solar energy were on the order of ± three tenths of a watt within a few years.
Finally, I am once again surprised by the overall stability of the system. Twelve-month averages of all three of the variables (the TOA balance, reflected solar, and upwelling longwave) are all stable to within about ± 0.3 watts per square metre. Out of a total of 340 watts per square metre going each way, that’s plus or minus a tenth of one percent … I call that extremely stable. Yes, with a longer sample size we’d likely see greater swings, but still, that’s very stable.
And that brings me back to the quotation from the paper where I started this post. They say that there is
… a consistent radiative imbalance at the top-of-atmosphere of about 1 W m−2 as observed for the past decade …
Now, according to their references [2] and [3], this claim is based on the idea that the excess energy is being soaked up by the ocean. And this claim has been repeated widely. I’ve discussed these claims here. The claims are all based on the Levitus ocean temperature data, which shows increasing heat in the ocean. Here’s my graph of the annual forcing needed to give the changes shown by Levitus in ocean heat content:
Figure 4. Annual forcing in watts per square metre needed to account for the energy going into or coming out of the ocean in the Levitus data. Data is for the top 2,000 metres of water. Note that despite average values being used, both by Hansen and also in the study under discussion, neither the mean nor the trend are statistically significant. Further discussion here.
For current purposes, let me point out that Figure 4 shows that in order for the ocean to gain or lose the energy that is shown in the Levitus data, it requires a very large year to year change in the amount of energy entering the ocean. That energy has to come from somewhere, and it has to go to somewhere when it leaves the ocean. Since the solar input is about constant over the period, that energy has to be coming from a change in either the upwelling longwave or the reflected solar … and we have precise (although perhaps inaccurate) data from CERES on those. Fortunately, the lack of accuracy doesn’t matter in this case, because we’re interested in the year to year changes. For that all we need is precision, and the CERES data is very precise.
So … let me compare the forcing shown by the Levitus ocean heat content in Figure 4, with the CERES data. Figure 5 shows the difference.
Figure 5. Forcing given by the Levitus ocean heat content data, compared to the CERES data shown in Figure 3.
As you can see, they have a couple of big problems with their claims of a consistent 1 W/m2 imbalance over the last decade.
First, it is contradicted by the very data that they claim establishes it. There is nothing “consistent” about what is shown by the Levitus data, unless you take a long-term average.
The second problem is with the Levitus data itself … where is the energy coming from or going to? While the CERES TOA imbalance is not accurate, it is very precise, and it would certainly show a fluctuation of the magnitude shown in the Levitus data. If that much energy were actually entering or leaving the ocean, the CERES satellite would surely have picked it up … so where is it?
I’ve discussed what I see as unrealistic error bars in the Levitus data here. My current comparison of Levitus with the CERES data does nothing to change my previous conclusion—the precision of the Levitus data is greatly overestimated.
Finally, the idea that we have sufficiently accurate, precise, and complete observations to determine the TOA imbalance to be e.g. 0.85 watts per square meter is … well, I’ll call it premature and mathematically optimistic. We simply do not have the data to determine the Earth’s energy balance to an accuracy of ± one watt per square metre, either from the ocean or from the satellites.
Best regards to all,
w.
MY OTHER POSTS ON THE CERES DATA:
Observations on CERES TOA forcing versus temperature
Time Lags In The Climate System
A Demonstration of Negative Climate Sensitivity
DATA:
CERES data: Unfortunately, when I go to verify it’s still available, I get:
The Atmospheric Science Data Center recently completed a site wide redesign.
It is possible that the page you are looking for is being transitioned. Please try back later.
If the page you have requested is still not available, it may have been renamed or deleted.
It is recommended that you use the Search interface on the ASDC Web Site to find the information you were looking for.
Since I got there via the aforementioned “Search interface on the ASDC Web Site”, I fear we’re temporarily out of luck.
[UPDATED TO ADD] I’ve collated the global and hemispheric monthly averages from R into a “.csv” (comma separated values) Excel file available here.
REFERENCES FOR THE NATURE CLIMATE CHANGE ARTICLE:
2. Hansen, J. et al. Earth’s energy imbalance: Confirmation and implications.
Science 308, 14311435 (2005).
3. Trenberth, K. E., Fasullo, J. T. & Kiehl, J. Earth’s global energy budget.
Bull. Am. Meteorol. Soc. 90, 311323 (2009).
4. Trenberth, K. E. An imperative for climate change planning: Tracking Earth’s
global energy. Curr. Opin. Environ. Sustain. 1, 1927 (2009).
5. Trenberth, K. E. & Fasullo, J. T. Tracking Earth’s energy. Science 328,
316317 (2010).
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Nice study ,but over too short a time period.
[REPLY—I’d like a longer period as well. But sadly, that’s the longest consistent measurement of the three crucial variables (upwelling and downwelling solar, and upwelling longwave) from the same platform that I can find. If you know of a longer one, I’d love to see it. -w.]
Willis, will you please stop doing sciency stuff and get with the program? It is because they say it is, not because the numbers add up!
All we can hope is that (a) nature refuses to play along – which will mean lots of people suffering – or (b) some of the up-coming generation of scientists aren’t already so brainwashed that they’ll pick up on the holes you keep poking!
another fantastic piece of forensic work.it is disturbing that the climate “scientists” themselves either do not analyse the data as thoroughly as yourself,or just plain ignore it.
The solar and reflected solar would be greatest when the Earth is closest to the sun in the NH winter. The upwelling longwave would be greatest when the land is warmest, in the NH summer. So it’s not surprising the two are 6 months apart.
BTW, nice refutation of the Levitus error bars.
I am not sure why, over the long term, we’d expect this energy imbalance to be anything other than zero. Even the physics of CO2 absorption spectra merely dictates that the energy is just trapped in the atmosphere for a bit more time, but over the long term, as much must leave as came in.
What would the findings be if solar irradiance were to drop by .2% and albedo were to increase by just 1%.
The answer would be different from what is shown in the sample presented in this article.
Still this is a good article.
As always you have an eye for spotting this kind of inconsistency. Nice work.
As always I have to rail against the use of simple running means , especially when looking for correlations on a comparable timescale.
See examples of distortion here:
http://climategrog.wordpress.com/2013/05/19/triple-running-mean-filters/
In the past you’ve used a gaussian filter which would be better, though I would recommend the triple running mean here to better remove the 12m cycle.
This is not pedantic when comparing signals like your figure 3. I’m not saying it is distorted since I have not done it with a different filter but choosing a better filter would be preferable than wondering whether it is doing something silly.
Best. Greg.
Game… set… match. Nice job.
If, as Hansen says, “instrumentation calibration factors were introduced to reduce the imbalance to the imbalance suggested by climate models” then of course no one must ever quote this data as evidence that validates the climate models. The quoted average imbalance is meaningless; seasonal variations may be useful.
This “high precision, low accuracy” observation is tantalizing – I’m sure the scientific team would love to figure out what the root cause is and have thus audited the original instrument calibration records in great detail.
Even if the CERES hardware is extremely accurate, how much confidence is there that it is capturing all energies at all wavelenghts? For example, if it was missing part of the UV spectrum the reflective figures could be low by about the 4-5 W/m2 mark.
In the last few days I’ve been wanting to see what the cropped off cosine that is the input to Artic region looks like when convoluted with linear feedback’s impulse response (decaying exponential) looks like.
A mental estimation was something very similar to the upwelling longwave line in figure 1.
Now as to why there is a residue of 5W before they start introducing fiddle factors derived from what the “knew” the answer was before looking at the data…
Reflected measured by satellite must be basically specular reflection. What happens when the satellite is looking into the rising sun reflected on open water or areas of melt-water? Does the radiometer get its protective flap closed to prevent it getting ‘blinded’ ?
I’ve had the idea for a while, that I have not had the opportunity to investigate, that direct reflection at low incidence is not being correctly measured (not modelled).
The time that this affects the satellite will be small but it is happening 24/7 during long periods in polar regions.
Could this explain the 5W paradox?
Willis, can’t we stop dicking around with all these models and statistics and just find the missing heat already! How hard can that be?
Seriously, nice work!
“Since I got there via the aforementioned “Search interface on the ASDC Web Site”, I fear we’re temporarily out of luck.”
Damn. Since you have a copy, maybe you could make it available somewhere (WUWT for example).
[Done. I’ve collated it from R into an Excel spreadsheet, available here as a .csv (comma separated values) file. -w]
Another great article. Thanks!
One little typo: the caption for figure 1 has the wrong colors listed for the various lines.
[Fixed, thanks. -w.]
joshv says:
August 30, 2013 at 10:16 am
No one, including myself, expects the long term to be anything other than zero. Basic considerations of physics require that.
The question has always been, how much does it vary in the short run? For me, the surprise was not just that the TOA balance doesn’t vary on an annual basis by more than ± 0.1%.
The additional surprise was that neither upwelling solar nor upwelling longwave varied by more than ± 0.1% year-to-year. Remember that the variable portion of the albedo is controlled by things as ephemeral as ice and clouds and wind, all of which are changing daily … and yet every year, they average out to within a tenth of a percent.
Amazing.
w.
JoshV
“I am not sure why, over the long term, we’d expect this energy imbalance to be anything other than zero. Even the physics of CO2 absorption spectra merely dictates that the energy is just trapped in the atmosphere for a bit more time, but over the long term, as much must leave as came in.”
People who know how physics work understand that. But the general public probably doesn’t, and I believe some scientists are banking on the public’s stupidity. They just keep pretending to conduct experiments that somehow prove that heat/energy is building up on this planet to the point where it will eventually throw the earth into chaos and cook us all.
They tell the public that the atmosphere of this planet is a “blanket” that acts more like a plastic film of Saran Wrap and holds in all the energy, or vents very little of it back into space. Since the earth’s atmosphere does NOT work that way, and the “missing heat” is sending up red flags, they must now find a way to claim that it is staying HERE on the planet somewhere…anywhere…it’s just hiding. And the ocean is the perfect fall guy.
There must be a third form of energy being emitted by the earth for which we have not taken into account. Someone needs to find this mysterious radiated form of energy. 😉
Wow. Uh, WOW. Just WOW.
The satellite measurements suggest trapping 5 W/m^2, this is regarded as implausible. SO MODELS ARE USED TO CALIBRATE THE MEASUREMENTS!?!
Complete and utter baloney. That’s not science. That’s fudge factors. The CERES data should be thrown out. It is very precisely measuring something that is completely useless.
Willis, can I ask you a possibly stupid question?
Why is it, that in all the discussions/studies/comments I’ve read about ocean heat, there NEVER, EVER seems to be even a mention of the fact that the core of this planet is HOT….FREAKING HOT…and that any “heat” in layers of the ocean below what can be heated by the sun/surface air temps, MIGHT actually be coming from BELOW the ocean’s floor?
It’s a basic scientific principle that heat RISES. Right? It doesn’t “sink” does it? It can be dragged deeper into the oceans by colder currents, but it cannot “hover” in some kind of magical Tupperware layer at a certain, mostly static layer. If it CAN, please tell me how! 🙂
Why is it that I NEVER, EVER hear any of the “leading oceanic experts” even remotely suggest that the undersea volcanic/thermal vents (the ones we DO know about-not to mention the staggering number of them we most likely DO NOT know about yet) spew the exact same amounts of CO2 into the water (and methane and debris and energy) that surface volcanoes do into the AIR? Is it not the most obvious question/theory (thank you Occam) that the OCEAN’S internal factors ARE MOST LIKELY raising the acidity, and heat, and CO2 levels in the OCEANS themselves? And that since CO2 and methane are gaseous, they RiSE to the surface of the ocean, and are then added to the ATMOSPHERE??
WHY….please explain to me, a humble, simple, uneducated fool what the scientific method is/was that determined that “volcanic output” as applied in scientific models does NOT include or factor in or even suggest underwater volcanic output at all? Are scientists so oblivious that it only counts as being “added to the atmosphere/Earth system” if they can SEE it happening on land or explain it coming from ABOVE the surface?
Randall-I know! Right?
Nice work in the right direction.
Is the data consistent with more reflection since 2000?
If so I suggest it is due to more global cloudiness from those more loopy jets with longer lines of air mass mixing. The Svensmark hypothesis would not be necessary on that basis though it may have some effect.
Hence oceans cooling and the recharge phase of ENSO being apparently a somewhat weak affair compared to the late 20th century period of active sun and reduced cloudiness.
Willis, something is not right, unless I’m losing my mind (always possible). The Earth’s orbit is quite eccentric. Aphelion is 152,000,000 km, perihelion is 147,000,000 km. The relative variation of TOA insolation must therefore by \Delta I = (P_s/4\pi R_p^2 – P_s/4\pi R_a^2 ). The Luminosity of the sun P_s = 3.85 x 10^26 Watts. Hence, 1418 W/m^2 at perihelion, 1326 W/m^2 at aphelion, \Delta I = 92 W/m^2. This is a roughly 7% annual variation. This is perhaps consistent with your top curve IF one does a whole lot of processing that is not described in your article. Is this just dividing by 4, the ratio between \pi R_e^2 and 4 \pi R_e^2? If so, precisely how are the other numbers measured/computed? In particular, how do they measure the reflected component compared to the LWIR fraction, given overlap in the spectra and a substantial geometric component to the former? How do they manage to measure this all over the globe? What are the error bars? Finally, there is a very interesting asymmetry between the TOA (averaged) reflected fraction, the TOA (averaged) insolation, and the TOA (averaged) LWIR that I’m trying to make sense of but failing.
It has the counterphase oscillation of outgoing LWIR compared to TOA insolation that in and of itself makes little sense since the TOA insolation is 7% higher at perihelion but outgoing LWIR is perhaps 3% lower, with the opposite true at aphelion. This SHOULD be related to albedo variations — it is difficult to imagine it being anything else — and hence should show up in the total reflection, but the reflection curve is phase lagged to be the same general (inverse) shape but IN phase with insolation. That strikes me as being almost impossible — it makes no sense. Reflection should produce an immediate, matching (or only slightly lagged) variation of outgoing LWIR, not an inverted variation shifted by six months!
I have a hard time seeing how there can be a reflection peak in phase with the insolation that doesn’t produce a similar shaped trough in the LWIR. This is one of the things I find very puzzling about the entire radiative balance issue. TOA insolation is varying by 7%. Albedo is varying far less (assuming that they are even getting this right, where I have my doubts as the Earthlight project was not finding mean albedo to be flat over 60 month stretches when it was running and I’m very skeptical that it is flat now). Outgoing LWIR is varying far less. The phases make no sense, and the amplitudes don’t add up in a way that I can explain offhand. This is the entire “Earth is warmest in aphelion” problem all over again, but the graphs above show the Earth as “warming” (in radiative imbalance) during perihelion, which just plain makes no sense. How can it be cooling with a positive radiation imbalance? Insolation is peaking, albedo is also peaking, global average temperature (reflected in LWIR) is at a minimum (already senseless, note well) but this senselessness is interpreted as “missing heat”? How about “numerical or computational error” instead?
I’m far from convinced that CERES has the precision or coverage to resolve missing heat, and would very much like to see some sort of quantitative explanation for the counterphase oscillations (as opposed to heuristic ones asserting different fractions of land vs ocean, which in the end have to add up in the imbalance as well).
rgb
What about the radiant energy that is converted to chemical energy by photosynthesis. If that
exceeds the heat energy released by both burning fuels and the slow oxidation of decaying plant life, couldn’t that be responsible for at least part of hidden energy?
Albedo, surface albedo, high angle ocean albedo, low angle ocean albedo, high cloud albedo, low cloud albedo, ice albedo, biological albedo, etc, etc, etc.
Changes in albedo over monthly, decadal, century, millenial and longer time scales. Yes, albedo overwhelms all other energy balance variables on any time scale, including diurnal.
You are starting to see the importance of the choice of Y-scale ranges on your charts. It is tempting to “zoom in” to “better see” what you are trying to see, but Figure 1 is the best view for telling the “big picture” on a global basis. Now add realistic error estimates and everyone can see and judge for themselves the microscopic influence of the CO2 variable compared to albedo.
Fig 2 has a good Y-scale range, or +/- 50 watts would be better.
The following charts should be held at Y-scales that are about 10 times the error estimate, or about +/- 10 watts. Holding Y-scale ranges at fixed values allow easier magnitude comparisons.
Humlum also has plots of OLR over longer time scales.
This report deserves commendation, and is the basis for a more comprehensive story, along with the earlier research on variable sensitivity with latitude.