More AGU: Tropical atmosphere radiative budget 1985-2005

This is not a topic that I follow, but I was intrigued by some comments in a poster by Penner and Andronova, both leaders in their field, and spent some time at this poster. The abstract stated:

A transient change in the balance between the incoming and outgoing radiation is an important indicator of the changing Earth’s climate. In this paper we use available data from satellites (1980 to present) and ground measurements (1995 to present) to reconstruct the long-term evolution of the energy budget of the tropical atmosphere (20S-20N). We compare the estimate of the radiative budget with the corresponding estimates obtained from model simulations from the AR4 database. We show that in spite of the dramatic increase in the model’s ability to simulate past and recent temperature change, the models show different sensitivities to the Mt. Pinatubo eruption and do not agree with observations of the overall radiative balance tendencies over 1980-2000.

First, they spliced and interpolated the available instrumental records for outgoing longwave radiation and shortwave radiation at the TOA in the tropiocs (20S-20N) (ERBE, CERES).

They then examined trends at TOA reporting:

  • “over 25 years, starting from 1985, the Earth’s system gained about ~2 wm-2, due primarily to the decrease in SW (~3 wm-2) in comparison with a smaller increase in the outgoing LW (~1 wm-2), thus defining an overall brightening of the Earth system as seen from space;
  • N_TOA preserves the signature of the Mt Pinatubo eruption as well as the signatures of El Nino-La Nina events – both phenomena resulting ina N_TOA redution (less energy “retained” by the Earth’s system) but most likely due to different causes: volcanic aerosols and clouds”
  • They reported that Pinatubo is represented well in “some” models, but that the El Nino-La Nina effect is poorly represented, as they miss the decrease in reflected radiation.

    They report that the total (diffused plus direct) solar radiation 1994-2006 from the World Radiation Data Center shows an overall positive trend of ~1.5 wm-2, which they say is consistent with the small negative trend in outgoing SW at the TOA, since less reflection would mean that more radiation would reach the surface, noting in particular that the total increase can be attributed to the Australia-Fiji area.

    Their conclusions are that:

  • the tropical atmosphere has absorbed less energy and the Earth’s surface has gained energy which is consistent with the temperature increase in the tropics;
  • the tropical atmosphere has recently become less reflective and more absorbing while the Earth’s surface gained radiative energy; thus, the tropical atmosphere had recently become more transparent to the incoming radiation and there is an overall brightening of the Earth’s system;
  • none of the AR4 models simulates the overall brightening of the Earth system. The majority of the models show a loss of radiative energy by the tropical energy in the post-Pinatubo period, suggesting that the models have still not properly captured the feedbacks between temperature change and clouds.
  • While I noted at the top that I’m not familiar with the issues in this area in detail, these results seemed interesting in that they seem to reconcile the failure of the tropical troposphere to warm at a greater pace than the tropical surface. I presume that the decreased reflectiveness of the tropical atmosphere is unrelated to GHGs but might have something to do with aerosols or clouds or both. This also doesn’t contradict prior masking of GHG effects by aerosol effects.

    However, the changes described here by Penner and Andronova are large ones and they seem like the sort of thing that should be got right by models being used for policy.

    39 Comments

    1. kim
      Posted Dec 18, 2007 at 9:00 AM | Permalink

      The Pinatubo Perturbation is a fine test, indeed. Not in the budget, though.
      ===========================

    2. Kenneth Fritsch
      Posted Dec 18, 2007 at 9:49 AM | Permalink

      none of the AR4 models simulates the overall brightening of the Earth system. The majority of the models show a loss of radiative energy by the tropical energy in the post-Pinatubo period, suggesting that the models have still not properly captured the feedbacks between temperature change and clouds.

      Is not the cloud feedback the well known and advertised weak link of all climate models and relates to the limited spatial resolution of the models compared to the cloud dimensions? From a layperson’s perspective, I would think that the models could plug in some kind of parameterization for clouds that would give a one time adjustment for some general cloud condition, but might not be easily adjustable for changes in cloud cover.

    3. tpguydk
      Posted Dec 18, 2007 at 10:05 AM | Permalink

      I am so glad that this stuff is coming out. This is how science should be done. Keep publicizing this.

    4. MattN
      Posted Dec 18, 2007 at 10:40 AM | Permalink

      http://www.uah.edu/News/pdf/climatemodel.pdf

    5. Peter D. Tillman
      Posted Dec 18, 2007 at 11:10 AM | Permalink

      Re Pinatubo: Steve, Kim

      Do either of you have a sensitivity estimate from the Pinatubo natural experiment? I have some notes on this from Bill Hyde (then at Duke; now Toronto) but they’re not accessible at present.

      Kim, are you JEG & J. Curry’s colleague at GA Tech?

      Steve, sounds like lotsa fun at AGU. Been a long time sinc I made that scene…

      Cheers — Pete Tillman, a bit envious

      “When confronted by a difficult problem, you can solve it more easily
      by reducing it to the question, “How would the Lone Ranger handle this?” –Dilbert

    6. kim
      Posted Dec 18, 2007 at 11:48 AM | Permalink

      No, P, I am double underline, lowercase, kim, among the ignorant and foolish laity.
      JEG deigned to allow me to comment anon at his blog about human frailty.
      ========================================

    7. Murray Duffin
      Posted Dec 18, 2007 at 11:50 AM | Permalink

      “over 25 years, starting from 1985, the Earth’s system gained about ~2 wm-2, due primarily to the decrease in SD (~3 wm-2) in comparison with a smaller increase in the outgoing LW (~1 wm-2), thus defining an overall brightening of the Earth system as seen from space;
      What is SD?

      Steve: SW

    8. kim
      Posted Dec 18, 2007 at 12:03 PM | Permalink

      MattN, if the gloves don’t fit, you must acquit.
      ============================

    9. jae
      Posted Dec 18, 2007 at 12:15 PM | Permalink

      Do either of you have a sensitivity estimate from the Pinatubo natural experiment? I have some notes on this from Bill Hyde (then at Duke; now Toronto) but they’re not accessible at present.

      Here.

    10. Posted Dec 18, 2007 at 12:41 PM | Permalink

      # 5 :
      Kim, are you JEG & J. Curry’s colleague at GA Tech?

      [Steve: snip – a simple no will suffice]

      Steve : i wonder if the models that got closer to the observed post-Pinatubo sensitivity are those that simulate the most realistic ENSO. Do you remember which ones they were from the poster ? Though it is taboo in an IPCC context to say that some models are better than others, it’s an open secret that a few of them fly consistently above the rest (particularly for tropical dynamics).

    11. Steve McIntyre
      Posted Dec 18, 2007 at 12:55 PM | Permalink

      #10. There was no information. They had a hand-out that I kept, but it doesn’t say which models did well or poorly at individual details.

      It did say, as noted above, that none of the models simulated the overall brightening of the Earth system. Again, I am not claiming knowledge of the details, merely trying to report. What would account for the failure of the models to simulate the brightening? (and the effect is not small – 2 wm-2 is more than half of doubled CO2 and showed up in only 20 years, a 20 year period of increased temperatures.

    12. lgl
      Posted Dec 18, 2007 at 12:55 PM | Permalink

      If this is correct;

      http://isccp.giss.nasa.gov/projects/browse_fc.html

      there must be quite a lot the models have not captured.
      Just about 0 W/m2 gained after 1984 (NET TOA).

    13. Posted Dec 18, 2007 at 1:17 PM | Permalink

      I’m having a little trouble following some of the text:

      the tropical atmosphere has recently become … more absorbing …thus, the tropical atmosphere had recently become more transparent

      In the context of an AGW fingerprint (or non-AGW fingerprint), I’m looking to see whether their conclusions suggest that the models under/over estimate cloud feedback, or whether the models under/over estimate convection.

    14. Papertiger
      Posted Dec 18, 2007 at 2:04 PM | Permalink

      I am confused by your terminology. Generally if the atmosphere is more transparent that would mean the Earth is less reflective, less bright, more absorbing of solar energy., higher temperature, higher albedo…

    15. Steve McIntyre
      Posted Dec 18, 2007 at 2:12 PM | Permalink

      It’s not “my” terminology. I’m quoting from the paper. The authors are at U of Michigan.

    16. Dennis Wingo
      Posted Dec 18, 2007 at 2:22 PM | Permalink

      It did say, as noted above, that none of the models simulated the overall brightening of the Earth system. Again, I am not claiming knowledge of the details, merely trying to report. What would account for the failure of the models to simulate the brightening? (and the effect is not small – 2 wm-2 is more than half of doubled CO2 and showed up in only 20 years, a 20 year period of increased temperatures.

      An interesting related paper

      http://www.sciencemag.org/cgi/content/abstract/304/5675/1299

      Steve, here is a link to an article about how the Earth’s albedo has varied over the last couple of decades. It would be interesting to see if there is a correlation between the albedo data, as taken from measuring the variation in reflected earth shine to the presentation that you talk about here.

      http://wattsupwiththat.wordpress.com/2007/10/17/earths-albedo-tells-a-interesting-story/

    17. steven mosher
      Posted Dec 18, 2007 at 3:23 PM | Permalink

      RE 10. JEG, you’re a tom waits fan?

      Someday a bum could break into song ( i liked your tale about SF bums)

      With a wacky visual twist. the melody that puts me up a tree.

    18. Posted Dec 18, 2007 at 4:55 PM | Permalink

      #17 :
      Yes Steven, i happen to think Mr Waits is the greatest songwriter of his generation. Are you a fan too ? Hey, may be we can agree on something…

      Regarding the tale of SF bums with surprising knowledge of dendroclimatology at breakfast, i told it to a friend and he said : “Are you sure it wasn’t [name] after a long night of drinking ?”

      [name] = insert name of long-bearded dendroclimatologist here.

      One for the dendros…. I’m sure some readers will appreciate.

    19. steven mosher
      Posted Dec 18, 2007 at 5:51 PM | Permalink

      RE 18. Yes JEG, I’ve been a huge Waits fan since 1980. I post Wait’s stuff here ocassionally
      for STAFFAN our friend in Sweden who doesnt get out of the house much ( just kidding STAFFAN)

      Glad you enjoyed your time in SF with our dendro enlightened bums.

      I had my ass handed to me in a speed chess game on market street one day by a guy
      who made Waits look like a princton preppy.

    20. Pat Frank
      Posted Dec 18, 2007 at 6:27 PM | Permalink

      If you look at Figures S8.5 and S8.7 in the Chapter 8 Supplemental Information of the WG1 section of the AR4, you’ll see that the GCMs used by the IPCC to make its predictions are many W/m^2 wrong in both reflected SW and outgoing LW TOA predictions.

      The information about the lack of consilience between the observations and the predictions made by the models is present in the AR4, but the IPCC officially ignores that in the SPM and even in the WG1 Technical Summary. In those sections, the IPCC claims >90% certainty that GHGs are responsible for warming global climate, whereas the discussion of error in WG1 Chapter 8 makes it very clear there is no such certainty to be had.

    21. Geoff Sherrington
      Posted Dec 18, 2007 at 6:49 PM | Permalink

      Re $ 4 MattN Australia wins

      I lifted the Table IIa from you reference

      A comparison of tropical temperature trends with model
      predictions
      David H. Douglass,a* John R. Christy,b Benjamin D. Pearsona† and S. Fred Singer

      This compares the results from 22 models of the temperature change with altitude to the tropopause. I wanted to see how well the Australian CSIRO performed.

      Here is the Table -

      Table II. (a). Temperature trends for 22 CGCM Models with 20CEN forcing. The numbered models are fully identified in
      Table II(b).
      Pressure (hPa)–>
      Surface 1000 925 850 700 600 500 400 300 250 200 150 100
      Model Sims.∗ Trends (milli °C/decade)
      1 9 128 303 121 177 161 172 190 216 247 263 268 243 40
      2 5 125 1507 113 112 123 126 138 148 140 105 2 −114 −161
      3 5 311 318 336 346 376 422 484 596 672 673 642 594 253
      4 5 95 92 99 99 131 179 158 184 212 224 182 169 −3
      5 5 210 302 224 215 249 264 293 343 391 408 400 319 75
      6 4 119 118 148 175 189 214 238 283 365 406 425 393 −33
      7 4 112 460 107 123 122 130 155 183 213 228 225 211 0
      8 3 86 62 57 58 82 95 108 134 160 163 155 137 100
      9 3 142 143 148 150 149 162 200 234 273 284 282 258 163
      10 3 189 114 200 210 225 238 269 316 345 348 347 308 53
      11 3 244 403 270 278 309 331 377 449 503 481 461 405 75
      12 3 80 173 114 115 102 98 124 150 161 164 166 142 4
      13 2 162 155 170∗∗ 182 225 218 221 282 352 360 340 277 −39
      14 2 171 293 190 197 252 245 268 328 376 367 326 278 69
      15 2 163 213 174 181 199 204 226 271 307 299 255 166 53
      16 2 119 128 124 140 151 176 197 228 271 289 306 260 120
      17 2 219 −1268 199 223 259 283 321 373 427 454 479 465 280
      18 1 117 117 126 148 163 159 180 207 227 225 203 200 163
      19 1 230 220 267 283 313 346 410 506 561 554 526 521 244
      20 1 191 151 176 194 212 237 254 304 387 410 400 367 314
      21 1 191 328 241 222 193 187 215 255 300 316 327 304 90
      22 1 28 24 46 73 27 −26 −26 −1 20 24 32 −1 −136
      Total simulations: 67
      Average 156 198 166 177 191 203 227 272 314 320 307 268 78
      Std. Dev. (σ) 64 443 72 70 82 96 109 131 148 149 154 160 124

      Australia’s results are remarkably close to the mean. Australia is number 15 of the stations. Starting from lowest altitude and going upwards in altitude, with results in millidegrees centigrade per decade, Australia VS mean is

      Aust Mean

      163 156
      213 198
      174 166
      181 177
      199 191
      204 203
      226 227
      271 272
      Then the figures start to diverge a little more.
      307 314
      200 320
      255 307
      166 268
      53 78

      The last digit in these columns is one part in a million of a degree C/decade.

      As a person with a general understanding of measurements and of climate model variability (see standard deviation given in the table), I would suspect that others would find this ppm correspondence fascinating. Indeed, if I were an examiner, I would ask for the raw data and the calculations to be explained in detail. Then, if all checked out, I’d say “Well done, chaps, you are as good as the ROW”.

    22. Steve H
      Posted Dec 18, 2007 at 6:57 PM | Permalink

      Apparently, NASA shutdown their Earthshine program after 2004 for the measurement of the Earth’s albedo. I have the scientific quality equipment needed, so I am stepping in, to continue this important program.

      From my location in Minnesota, I am able to measure the albedo over the Pacific ocean between America and Australia. For full global coverage, other dedicated volunteers in Australia and Europe will need to be organized.

      With my 10 inch diameter telescope, a astronomy quality DSLR (Canon 350D) camera and a spectrometer, I already have what is needed for scientific measurements. Over the last two months, I have been obtaining outstanding images of the Moon’s Earthshine, which is now being archived for future analysis.

      Currently, I am in the process of calibrating my telescope and camera against known stars, to measure the spectral response of the system. Using the known magitude of many stars, I am also insuring that I can accurately calibrate the intensity of the light being measured.

      Why NASA quit monitoring the albeto of the Earth after 2004 is beyond me, but this is an important measurement.

    23. Posted Dec 18, 2007 at 7:10 PM | Permalink

      Mosh #19: I’ve been following Waits since the late 70s. At one time I could do a pretty good impression:

      “Small Change got rained on by his own .38,
      And nobody flinched down by the arcade . . .”

      I read an interview with him once. He was asked who had influenced him, whose music he liked. He said, “Everyone I like is either dead or not feeling very well.”

    24. Dennis Wingo
      Posted Dec 18, 2007 at 7:14 PM | Permalink

      Steve

      Do you have any links to the closing of this program?

      Thanks

    25. Steve H
      Posted Dec 18, 2007 at 7:40 PM | Permalink

      #24 and 25:

      This is a subject that I am very interested in and I have been trying to obtain every source of information about this topic of research that I can find.

      From the Big Bear observatory, where NASA’s Earthshine program was being conducted, all data seems to end after 2004. If they are still doing this research, then it has not been updated recently.

      http://www.bbso.njit.edu/Research/EarthShine/espaper/earthshine_proposal.html

      I hope to use everything that they have learned in an effort to calibrate my own data. If anyone has more information about this subject, please let me know.

      However, if an amateur astronomer with scientific quality equipment can continue this research, then I am more than happy to step in and do my part.

    26. Paul Penrose
      Posted Dec 18, 2007 at 10:26 PM | Permalink

      Steve H.
      Thank you.

    27. George M
      Posted Dec 18, 2007 at 10:32 PM | Permalink

      Steve H:

      I’m not sure why Anthony Watts hasn’t checked in here, but he had a mention of more recent work at Big Bear on his blog last month or Oct. My memory is rotten, but I *think* some is still going on, or perhaps it is going to be resumed. Drop Anthony an email at surfacestations.org/ and see what he knows.

    28. steven mosher
      Posted Dec 19, 2007 at 8:36 AM | Permalink

      re 23 theduke

    29. henry
      Posted Dec 19, 2007 at 3:27 PM | Permalink

      Here’s the post from Anthony’s site about “earthshine” at BSSO

      He had emailed the PI, not sure what he got back.

    30. Geoff Sherrington
      Posted Dec 19, 2007 at 4:38 PM | Permalink

      Re # 21 Sherrington

      Correcting a mistake. WRONG

      The last digit in these columns is one part in a million of a degree C/decade.

      Corrected (et seq) The last digit in these columns approaches one part in a million of a degree ABSOLUTE/decade.

    31. Posted Dec 19, 2007 at 5:08 PM | Permalink

      Re 11 :

      “What would account for the failure of the models to simulate the brightening? ”

      I wish i knew. I’m really not the person to ask, have stayed away from GCMs for a long time..

      ” (and the effect is not small – 2 wm-2 is more than half of doubled CO2 and showed up in only 20 years, a 20 year period of increased temperatures).”

      The number is have in head for 2xCO2 is around 4 W.m-2.
      2 W.m-2 is close to the current climate forcing (1.8 W.m-2 i saw on one of Jim Hansen’s graph in 2005, mas o menos), with aerosols partially offsetting GHG. So yes, that would be a very big signal…

    32. steven mosher
      Posted Dec 19, 2007 at 6:07 PM | Permalink

      Estimating clouds make me think if this: cloud busting

      free yourself! Bingo.

      Seriously, does anyone have clear theory of cloud formation and the attentant brightening or
      lack thereof? I suspect it’s a big unknown. That’s ok as long as the uncertainity is reflected in the
      projections.

    33. bender
      Posted Dec 19, 2007 at 6:57 PM | Permalink

      That’s ok as long as the uncertainity is reflected in the projections.

      GCM uncertainty is brought out only when it is essential to refute papers by denialists like Christy et al. After that, it goes back in Pandora’s black box.

    34. steven mosher
      Posted Dec 19, 2007 at 7:48 PM | Permalink

      RE 33. that was an astounding wasnt it. Now gavin wants to use GCM runs to counter
      Ross’s paper.. See that thread on RC ( I’m out of the penalty box again)

      Get this: Look at a bunch of GCM runs to see if Ross is right. He didnt even think
      of the inplications of doing multiple tests, didnt think what it meant that GCMs runs did not match
      reality, doesnt even consider the fact that Ross’ theory ( UHI infection is true) is the most easily
      maintained theory…

      Arrgg. Dumb fat and stupid is no way to go through life.

    35. maksimovich
      Posted Dec 19, 2007 at 11:31 PM | Permalink

      DMS

    36. MJW
      Posted Dec 21, 2007 at 3:30 AM | Permalink

      Now gavin wants to use GCM runs to counter Ross’s paper…

      I think it’s almost undeniable that the GCMs are tuned to match the global temperature record; if not by explicitly adjusting the parameters, then implicitly, by rejecting models that fail to match the record. A recent thread discussed the inverse relation in different models between total 20th century anthropogenic forcing and climate sensitivity, which is evidence of such tuning.

      If, as Ross McKitrick’s paper claims, the temperature record is faulty, then the GCMs are tuned to produce incorrect results. That undermines whatever value the model output might otherwise have in deciding the issue. It also suggests that the reliability of the GCMs projections is limited by the accuracy of the surface temperature record. (The GCMs might also be tuned to the satellite record, but that seems inconsistent with the poor match discussed in Christy’s recent paper, and with the insistent claim by climate scientists that the surface record is more reliable.)

    37. yorick
      Posted Dec 21, 2007 at 6:15 AM | Permalink

      Noted straw man vandal Eli Rabbet has no response for it. Got into a long argument with him over on Motl’s blog. I think McKitrick’s paper has struck a chord even among the group thinkers over at RC.

    38. Pierre Gosselin
      Posted Dec 21, 2007 at 7:32 AM | Permalink

      Concerning Raypierre’s comment:
      “…as Tom would happily tell you, the Middle Ages were not as generally warm as the present.”

      One observant RC reader remarked:
      “Why would he be “happy” about such a fact, and is he really? Where does this kind of emotional involvement in paleoclimate reconstructions come from? I mean, one could also be happy about the Middle Ages having been warmer than the present, couldn’t one? Maybe even happier than Tom?”

      The folks at RC just don’t want to believe that we may not have a serious problem after all. I mean, who wants to be suddenly unneeded and unemployed?

    39. SteveSadlov
      Posted Dec 21, 2007 at 10:59 AM | Permalink

      RE: #36 – “When did China start pumping out large quantities of sulphuric acid?”

      Although there was low level industry prior to WW2, the real surge began after. Mao was somewhat mimicking Stalin and focussed on heavy industrial development, steel mills, etc. By the 70s, the basic infrastructure for an East Asian Ruhr (or actually, a set of Ruhr’s) was essentially in place. Then came the more advanced industries, starting at the component level and working higher and higher in the food chain. It is now essentially at a 21st century Euro American level, albeit, with far fewer environmental controls (if any). Still huge piles of coal everywhere – powering everything from small furnaces and on site generation plants of mom an pop sub sub sub tier suppliers to 20 stack major power plants and brand new steel mills. A necklace of Ruhrs, with Puget Sounds, (old) Detroits, and Silicon Valleys layered on top.

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