Guilyardi et al (2009) “Understanding El Niño in Ocean-Atmosphere General Circulation Models: progress and challenges”
Guest post by Bob Tisdale
The preliminary Reynolds OI.v2 sea surface temperature data for July 2012 won’t be available until next Monday July 30th, and there haven’t been any changes in weekly NINO3.4 region or global sea surface temperature anomalies since the update last week that are worth a separate post. So I’ve decided to give readers a heads-up about a paper I’m using as a primary reference for Chapter 5.8 Scientific Studies of the IPCC’s Climate Models Reveal How Poorly the Models Simulate ENSO Processes of my upcoming book Who Turned On The Heat?: El Niño-Southern Oscillation, the Unsuspected Global Warming Culprit.
The paper is Guilyardi et al (2009) Understanding El Niño in Ocean-Atmosphere General Circulation Models: progress and challenges. It is basically an overview of the many problems experienced by climate models in their attempts to simulate ENSO, and as such they cite more than 100 other papers. Many of the cited papers discuss individual climate model problems, while others look at many models, while still other papers are detailed discussions of ENSO processes. If you’re not extremely familiar with ENSO, some of the topics may be overly technical. On the other hand, some of the problems discussed may even seem nitpicky, but Guilyardi et al do explain why these model errors are, in fact, problems.
The “sidebar” discussions, highlighted in burnt orange, are about how wellpoorly climate models capture the mean state and annual cycle of the tropical Pacific. The models have such severe problems with their portrayal of the mean state and annual cycle that you’re left asking yourself one question: With all of those problems, how could the modelers think that the El Niño and La Niña events they place atop the mean state have any chance at capturing reality?
During their discussion of the model portrayal of El Niño and La Niña events, Guilyardi et al (2009) use the term “skewness”. With skewness, they’re referring to the fact that since 1976, El Niño events have been stronger than La Niña events. ENSO has been skewed toward the El Niño phase. But as Guilyardi et al (2009) discuss, they’re not in the climate models. Modeled La Niña events tend to be the same strength as El Niño events. Let’s take that further. If the models also produce the same number of La Niña events as El Niño events, then modeled ENSO would become a nonentity. Is this the reason why models show the equatorial Pacific warming nearly as fast as, or faster than, the mid latitudes, depending on model vintage? (See Figure 1, which is Figure 5-37 from my upcoming book.) When in reality, the equatorial Pacific has cooled over the past 30 years, while the mid latitudes have warmed. This indicates to me that in the real world, ENSO-related processes are distributing warm water from the tropics toward the mid latitudes in the Pacific—something that’s not captured by the models. And that’s a big problem.
Figure 1
In the upcoming book Who Turned On The Heat?: El Niño-Southern Oscillation, the Unsuspected Global Warming Culprit, I discuss and illustrate the major problems with climate models presented by Guilyardi et al to make them easier to understand. But there is a sentence in that paper that needs no further explanation. They write:
Because ENSO is the dominant mode of climate variability at interannual time scales, the lack of consistency in the model predictions of the response of ENSO to global warming currently limits our confidence in using these predictions to address adaptive societal concerns, such as regional impacts or extremes (Joseph and Nigam 2006; Power et al. 2006).
Do you think that sentence will make it to the IPCC’s 5th Assessment Report? It should.
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Very fine paper. I note at line 789, it is suggested that BEST apply the new classification rules to their stations outside the US.
I didn’t know about the new rules, but I did suggest to Elizabeth Muller that BEST undertake something like the surface stations project. Here is our email correspondence.
________________________________________
From: lance wallace [mailto:lwallace73@verizon.net]
Sent: Sunday, February 20, 2011 4:23 PM
To: info@berkeleyearth.org
Subject: Comment on BEST methodology
Dear Dr. Muller:
Having read over your methdology, I believe you are missing a crucial element–on-site awareness of the station attributes (does it meet NOAA criteria), and even more difficult, knowledge of the history of the station, its relocations if any, population change of the nearest town, and so on.
I recognize this is a tall order for 38000 stations around the world. However, interest in this topic is at such a high point that perhaps you could multiply your efforts by a factor of thousands, as was done by Anthony Watts in the Surface Stations project. That effort, as you know, resulted in photographic proof that something like 90% of the U.S. stations were sited in non-accordance with the written criteria. It is a mystery to me that NOAA/NASA did not immediately begin to set up stations that do meet the criteria. (Or possibly they are doing something in a small way now). Would it not be possible for you to provide your list of 38000 station locations and call for volunteers to investigate those closest to their homes? This would unleash a tremendous creative and energetic potential from all those who feel somewhat helpless now.
Lance Wallace
Dear Lance,
Thank you very much for your inquiry. We met with Anthony Watts several weeks ago, and will be working with him and using his data regarding the US station attributes to compare stations that do and do not meet the criteria. I think a similar effort around the world would be very interesting, and we will provide the list of our station locations when we release our data (which should be within a few months). Like you, we would love to see the results of such a global effort.
Best regards,
Elizabeth
________________________________________
From: lance wallace [mailto:lwallace73@verizon.net]
Sent: Tuesday, March 15, 2011 3:08 PM
To: Elizabeth Muller
Subject: Re: Comment on BEST methodology
Dear Dr. Muller–
Thank you for responding to my suggestion. I am, of course, pleased that you would view a global “Surface Stations” effort favorably. However, I am also disappointed that the BEST team appears not be grasping the nettle. Surely the time to look at the quality of the stations is before, or at least as nearly as possible simultaneously with, the release of the results. The best group to undertake this effort is precisely yourselves! You have raised hopes in those who view the present temperature measurements as flawed. I think you could harness the energy of hundreds of persons worldwide to look at the quality of the stations. It would be a cruel letdown if your approach suffers from the same reliance on poor quality stations as the present system.
Is there any reason why you could not release the list of station locations now rather than waiting until the data has been analyzed? If the release were accompanied with a request for help in understanding the history of the stations, I see no real down side, and the possibility of an outpouring of effort to help us understand your results.
Lance Wallace
Dear Lance,
All of the data we are using is already available on the web, but from many different sources and using different formats. It is an enormous amount of work putting the data in a format that other people can easily access and use, which is what we’ve been doing. This is not a trivial task and we are working as quickly as we can. We will make the full data set available to the public as soon as possible; we ourselves have not yet analyzed the full 100% sample.
Regards
Elizabeth
It appears that my fear of a “cruel letdown” was unfortunately correct.