An interesting new paper has been published:
Spencer, Roy W.; Braswell, William D.; Christy, John R.; Hnilo, Justin (2007)
Cloud and radiation budget changes associated with tropical intraseasonal oscillations
Geophys. Res. Lett., Vol. 34, No. 15, L15707
Abstract
We explore the daily evolution of tropical intraseasonal oscillations in satellite-observed tropospheric temperature, precipitation, radiative fluxes, and cloud properties. The warm/rainy phase of a composited average of fifteen oscillations is accompanied by a net reduction in radiative input into the ocean-atmosphere system, with longwave heating anomalies transitioning to longwave cooling during the rainy phase. The increase in longwave cooling is traced to decreasing coverage by ice clouds, potentially supporting Lindzen’s “infrared iris” hypothesis of climate stabilization. These observations should be considered in the testing of cloud parameterizations in climate models, which remain sources of substantial uncertainty in global warming prediction.
Received 15 February 2007; accepted 16 July 2007; published 9 August 2007.
The UAH press release is here.
Cirrus disappearance: Warming might thin heat-trapping clouds
The widely accepted (albeit unproven) theory that manmade global warming will accelerate itself by creating more heat-trapping clouds is challenged this month in new research from The University of Alabama in Huntsville.
Instead of creating more clouds, individual tropical warming cycles that served as proxies for global warming saw a decrease in the coverage of heat-trapping cirrus clouds, says Dr. Roy Spencer, a principal research scientist in UAHuntsville’s Earth System Science Center.
That was not what he expected to find.
“All leading climate models forecast that as the atmosphere warms there should be an increase in high altitude cirrus clouds, which would amplify any warming caused by manmade greenhouse gases,” he said. “That amplification is a positive feedback. What we found in month-to-month fluctuations of the tropical climate system was a strongly negative feedback. As the tropical atmosphere warms, cirrus clouds decrease. That allows more infrared heat to escape from the atmosphere to outer space.”
The results of this research were published today in the American Geophysical Union’s “Geophysical Research Letters” on-line edition. The paper was co-authored by UAHuntsville’s Dr. John R. Christy and Dr. W. Danny Braswell, and Dr. Justin Hnilo of Lawrence Livermore National Laboratory, Livermore, CA.
“While low clouds have a predominantly cooling effect due to their shading of sunlight, most cirrus clouds have a net warming effect on the Earth,” Spencer said. With high altitude ice clouds their infrared heat trapping exceeds their solar shading effect.
In the tropics most cirrus-type clouds flow out of the upper reaches of thunderstorm clouds. As the Earth’s surface warms – due to either manmade greenhouse gases or natural fluctuations in the climate system – more water evaporates from the surface. Since more evaporation leads to more precipitation, most climate researchers expected increased cirrus cloudiness to follow warming.
“To give an idea of how strong this enhanced cooling mechanism is, if it was operating on global warming, it would reduce estimates of future warming by over 75 percent,” Spencer said. “The big question that no one can answer right now is whether this enhanced cooling mechanism applies to global warming.”
The only way to see how these new findings impact global warming forecasts is to include them in computerized climate models.
“The role of clouds in global warming is widely agreed to be pretty uncertain,” Spencer said. “Right now, all climate models predict that clouds will amplify warming. I’m betting that if the climate models’ ‘clouds’ were made to behave the way we see these clouds behave in nature, it would substantially reduce the amount of climate change the models predict for the coming decades.”
The UAHuntsville research team used 30- to 60-day tropical temperature fluctuations – known as “intraseasonal oscillations” – as proxies for global warming.
“Fifteen years ago, when we first started monitoring global temperatures with satellites, we noticed these big temperature fluctuations in the tropics,” Spencer said. “What amounts to a decade of global warming routinely occurs in just a few weeks in the tropical atmosphere. Then, as if by flipping a switch, the rapid warming is replaced by strong cooling. It now looks like the change in cirrus cloud coverage is the major reason for this switch from warming to cooling.”
The team analyzed six years of data from four instruments aboard three NASA and NOAA satellites. The researchers tracked precipitation amounts, air and sea surface temperatures, high and low altitude cloud cover, reflected sunlight, and infrared energy escaping out to space.
When they tracked the daily evolution of a composite of fifteen of the strongest intraseasonal oscillations they found that although rainfall and air temperatures would be rising, the amount of infrared energy being trapped by the cloudy areas would start to decrease rapidly as the air warmed. This unexpected behavior was traced to the decrease in cirrus cloud cover.
The new results raise questions about some current theories regarding precipitation, clouds and the efficiency with which weather systems convert water vapor into rainfall. These are significant issues in the global warming debate.
“Global warming theory says warming will generally be accompanied by more rainfall,” Spencer said. “Everyone just assumed that more rainfall means more high altitude clouds. That would be your first guess and, since we didn’t have any data to suggest otherwise …”
There are significant gaps in the scientific understanding of precipitation systems and their interactions with the climate, he said. “At least 80 percent of the Earth’s natural greenhouse effect is due to water vapor and clouds, and those are largely under the control of precipitation systems.
“Until we understand how precipitation systems change with warming, I don’t believe we can know how much of our current warming is manmade. Without that knowledge, we can’t predict future climate change with any degree of certainty.”
Spencer and his colleagues expect these new findings to be controversial.
“I know some climate modelers will say that these results are interesting but that they probably don’t apply to long-term global warming,” he said. “But this represents a fundamental natural cooling process in the atmosphere. Let’s see if climate models can get this part right before we rely on their long term projections.”
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Hey these guys just discovered due piont is a tricky biz.
Paul: This is a very thin argument against continued AGW. see the Doug Smith PR this week
There is also this lot. See top of the list for watervapour feedback
http://www.nerc-essc.ac.uk/~rpa/publications.html
It’s well known that clouds defeat climate models.
Alarmism relies on overall feedback being positive. The large negative feedback suggested here comes as no surprise to some of us, and is in keeping with empirical evidence from earth’s long history suggesting climate sensitivity to CO2 is low.
I noticed the Doug Smith stuff today in Science, and on the BBC website – I haven’t had chance to read it yet. The media seem to be selective in the papers that they report!
Gavin says the argument is thin, then points to a sea of references. This is not a counter argument, it is slight of hand, a diversion. Gavin, please provide a paper or book we can access that explains how the Spencer et al article is weak. Hint: most of IPCC is infinitely recursive opinion, so most of it is not convincing.
Gavin calls the argument weak, then cites another sea of references. I consider this slight of hand, not argument. Please, Gavin, provide us with a paper or book we can get our hands on that shows how the Lindzen iris cannot possibly exist.
http://www.realclimate.org/index.php/archives/2006/04/lindzen-point-by-point/
is not very convincing.
Allan Ames: I’m neither scientist nor engineer so I depend on others doing the hard yards
That sea of information includes “Climate Models and Their Evaluation”
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_Ch08.pdf
See 8.6.3.2.4 “Conclusion on cloud feedbacks” for a neat summary of our model science.
IMHO Morano’s lot hardly dents the sphere as we know it today. When Spencer & Co summed their work this way –
“I know some climate modelers will say that these results are interesting but that they probably don’t apply to long-term global warming,” he said. “But this represents a fundamental natural cooling process in the atmosphere. Let’s see if climate models can get this part right before we rely on their long term projections.”
I reckoned they expected a hiding over time. We should ask Smith at the UK met if it makes any difference to their new model hey
For a dozen years or so I used to monitor vast industrial hot houses that were largely closed to the sun. Part of my job was to make certain it did not rain as our atmosphere approached 100 % saturation because of the accumulated rubbish related to slime that only grows in clouds. We generally produced a bright white product but we mostly burnt fossils to produce huge amounts of heat. Evaporation techniques vas also my bread and butter.
I think I understand how climate science is catching up to Greenhouse better than most
BTW Allan; what’s your interest and background in this? It could help others answer your questions for papers etc.
Gavin: Thank you for the answer. I am all for models, but they are not experiments, merely expressions of ideas in the form of numbers.
Could it be that the distribution of nucleii are related to convection history in such a way as to create an iris effect?
Upstream from all this large scale industrial evaporation was a boiler house containing several furnaces. Obtaining fuel efficiency in our heat engines requires a fair understanding of atomization and mixing in turbulent environments. Feedback in automation of these environments needs to be always negative. Monitoring outputs doesn’t help when the phase response is wrong. Positive feedback is often the result of system response. Knowing system sensitivity is only part of the problem and I guess that supposes we can control it in the first place.
All this practical modeling came before computers Allan.
Gavin: After years chasing photons through solids and liquids, I built first DDC then multivariate chemical process control systems. Maybe we should set up a blog for industrial horror stories.
No question, GCM’s are some of the most complicated things humans have ever attempted, to which effort you have contributed. But they model an even more complicated and nonlinear process. It would be great fun if it weren’t so important. As long as any significant phenomenon remains unaddressed, I consider all long term predictions as tentative. I know clouds are a problem, and because of ice nucleation, I expect high altitude clouds are even more so.
There are several iris possibilities which could be tested statistically. Maybe the data even exists. Is it possible to peruse satellite data?
Thank you
Allan
Allan: Although it would be great to reminisce and perhaps go on a bit after years in haz chem. Industries, I know I can’t do the math or write well enough to save myself. But there is one more yarn I hope worth repeating.
Years ago it seems now I was granted an hour with the technician driving Australia’s first electron microscope. She was previously an expert in producing ultra thin slices of metal for analysis and had just graduated to producing high res crystal photos on the new instrument. I wondered then what those poster sized pics told us about the top secret Avon Saber being built next door or the crashed DH Sea Venom wing in the destruction test rig outside.
It took me years to get some proper perspective for evaluating the various post war industry operated R&D projects with out resorting to math. In the end it all comes down to our ability to run the show with out the aid of accurate instruments. On a big boiler we need only a WG u tube manometer on the fire box and a bourdon tube pressure gauge on the steam drum. If we were totally blind our fall back position is the furnace explosion door and the steam pressure relief valve. Critical calibration checks is simply by puff and dead weights.
Tig Duigan flew before the electron microscope, so did his dad.
http://www.abc.net.au/7.30/content/2007/s2001209.htm
First; we must believe in our ability to make do in the absence of perfection. I flew with several pilots who regularly landed on some wild beach when they could.
The thing about Lindzen’s “infrared iris” is it must work both ways and what about UV?
Why do we have to wait before taking positive action? We are taking action either way, since our current course is to keep pumping CO2 into the atmosphere at an increasing rate. We have no, “I’ll just sit back and wait till we are 100% positive” option.
We shouldn’t be funding the global warming alarmism industry or trying to control the weather/climate – we should be putting all the effort/funds into finding VIABLE new energy resources – but we aren’t.
Of course, ‘WE’ includes China etc – unilateral ‘action’ is futile.
Gavin: On the first acceptance test of our new DDC control system – a chemical reaction with three fluids, two electrodes, and cascade temperature control – on startup the system was limit locked, and had to be rebooted to restart. This start up behavior was a problem for weeks. After long weekends studying logs, it turned out some technicians would start the control system before the response system, and the digital integrators would fill up with hours of 100% error signal. With real, imperfect capacitors in the analog control systems no one even knew such a problem could exist. Now, I enjoy computers. I sometimes practice masochism writing Fortran under Windows. I have published papers with math in them. And I know as an absolute fact of life that computer programs can only be trusted to the extent they can be tested.
Admittedly, there is never total knowledge, and there can never be. Those who are not willing to pore through the math are forced to accept that the programmers have properly rendered the balance between physics and the statistics (which seems to be in predominance). I would like the option of going trough the math and the statistics.
The Model E F90 browser is neat. Thank you. I have spend a bit of time with it. In some ways figuring out what GCM code is doing is like figuring out how the US economy works by watching trailer trucks go by; you don’t know if they are empty or full or where they are ultimately going, just that they went.
Somewhere in NASA there have to be stacks of working reports that were the instruction given to the programmers. These documents would much better convey what was intended for the program(s) than the actual code can. I expect that there will be validation studies in this file as well. Is there any chance that the working reports could be made available?
Yes, Lindzen’s effect could go two ways, and possibly capture NLTE radiation as well. We need to find the effect to quantify its impact.
Thanks,
Allan
Paul
it is the scientists investigating AGW who have been calling for new energy sources to be developed from the start. It is the deniers who keep on insisting they do more research. When they do, they are told off for wasting money that could have been put into developing new energy sources. It’s a neat double bind you have put these people in.
Allan: After reading your response I tickled google foe a bit more on Fortran and found this lot on ‘FORTRAN Codes for the Computation of the Bidirectional Reflection Function for Flat Particulate Layers and Rough Surfaces’
http://www.giss.nasa.gov/~crmim/brf/
-“The code brf.f solves the Ambartsumian’s nonlinear integral equation for the reflection function using a simple iterative method. Since this technique bypasses the computation of the internal field, it is by far the fastest and most accurate numerical approach available”-
If “F. whatever” exists for surfaces, oceans, ocean shadows etc, why not clouds, even cirrus clouds?
Let clouds opened up like a Venetian blind be bidirectional F.’iris’
Now I’m right out of my depth hey
Gavin: Thanks for the scattering code. I had not thought of NASA as a source of code, but it is, of course. Now if I can just get that little bit about the ice heteronucleation fixed, and the other 130000 lines of code to compile, we should have it working.
Allan