| From | Ben Santer | Date | Fri, 25 Apr 2008 13:19:18 -0700 |
|---|---|---|---|
| To | Peter Thorne, Leopold Haimberger, Karl E.Taylor, Tom Wigley, John Lanzante, Susan Solomon, Melissa Free, peter gleckler, Phil Jones, Karl E.Taylor, Steve Klein, carl mears, Doug Nychka, Gavin Schmidt, Steven Sherwood, Frank Wentz | ||
| Subject | [Fwd: Re: JOC-08-0098 - International Journal of Climatology] | ||
Dear folks, On April 11th, I received an email from Prof. Glenn McGregor at IJoC. I am now forwarding that email, together with my response to Prof. McGregor. Prof. McGregor's email asks for my opinion of an "Addendum" to the original DCPS07 IJoC paper. The addendum is authored by Douglass, Christy, Pearson, and Singer. As you can see from my reply to Prof. McGregor, I do not think that the Addendum is worthy of publication. Since one part of the Addendum deals with issues related to the RAOBCORE data used by DCPS07 (and by us), Leo responded to Prof. McGregor on this point. I will forward Leo's response in a separate email. The Addendum does not reference our IJoC paper. As far as I can tell, the Addendum represents a response to discussions of the original IJoC paper on RealClimate.org. Curiously, Douglass et al. do not give a specific source for the criticism of their original paper. This is rather bizarre. Crucially, the Addendum does not recognize or admit ANY ERRORS in the original DCPS07 paper. I have not yet heard whether IJoC intends to publish the Addendum. I'll update you as soon as I have any further information from Prof. McGregor. With best regards, Ben ---------------------------------------------------------------------------- Benjamin D. Santer Program for Climate Model Diagnosis and Intercomparison Lawrence Livermore National Laboratory P.O. Box 808, Mail Stop L-103 Livermore, CA 94550, U.S.A. Tel: (925) 422-2486 FAX: (925) 422-7675 email: santer1@llnl.gov ---------------------------------------------------------------------------- Attachment Converted: "c:\eudora\attach\[Fwd Re JOC-08-0098 - Interna.pdf" X-Account-Key: account1 Return-Path: Received: from mail-1.llnl.gov ([unix socket]) by mail-1.llnl.gov (Cyrus v2.2.12) with LMTPA; Fri, 11 Apr 2008 11:19:24 -0700 Received: from smtp.llnl.gov (nspiron-3.llnl.gov [128.115.41.83]) by mail-1.llnl.gov (8.13.1/8.12.3/LLNL evision: 1.6 $) with ESMTP id m3BIJN5F012995 for X-Attachments: None X-IronPort-AV: E=McAfee;i="5200,2160,5272"; a="31695223" X-IronPort-AV: E=Sophos;i="4.25,642,1199692800"; d="scan'208";a="31695223" Received: from dione.llnl.gov (HELO [128.115.57.29]) ([128.115.57.29]) by smtp.llnl.gov with ESMTP; 11 Apr 2008 11:14:37 -0700 Message-ID: <47FFAA8D.8040308@llnl.gov> Date: Fri, 11 Apr 2008 11:14:37 -0700 From: Ben Santer Reply-To: santer1@llnl.gov Organization: LLNL User-Agent: Thunderbird 1.5.0.12 (X11/20070529) MIME-Version: 1.0 To: g.mcgregor@auckland.ac.nz CC: Leopold Haimberger "Thorne, Peter" Subject: Re: JOC-08-0098 - International Journal of Climatology References: <363780847.1207875178234.JavaMail.wladmin@tss1be0004> In-Reply-To: <363780847.1207875178234.JavaMail.wladmin@tss1be0004> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Dear Prof. McGregor, Thank you for your email, and for your efforts to ensure rapid review of our paper. Leo Haimberger (who has led the development of the RAOBCORE* datasets) and Peter Thorne would be best placed to comment on the first issue raised by the Douglass et al. "Addendum". As we show in Figure 6 of our IJoC paper, recently-developed radiosonde datasets which do not rely on reanalysis data for correction of inhomogeneities (such as the Sherwood et al. IUK product and the Haimberger et al. "RICH" dataset) yield vertical profiles of atmospheric temperature change that are in better agreement with model results, and quite different from the profiles shown by Douglass et al. The second issue raised in the Douglass et al. "Addendum" is completely spurious. Douglass et al. argue that their "experimental design" involves involves "comparing like to like", and satisfying "the critical condition that the model surface temperatures match the observations". If this was indeed their experimental design, Douglass et al. should have have examined "AMIP" (Atmospheric Model Intercomparison Project) simulations, in which an atmospheric model is run with prescribed changes in observed time-varying sea-surface temperatures (SSTs) and sea-ice distributions. Use of AMIP simulations would allow an analyst to compare simulated and observed tropospheric temperature changes given the same underlying changes in SSTs. But Douglass et al. did NOT consider results from AMIP simulations, even though AMIP data were freely available to them (AMIP data were in the same "CMIP-3" archive that Douglass et al. accessed in order to obtain the model results analyzed in their original IJoC paper). Instead, Douglass et al. examined results from coupled model simulations. As we discuss at length in Section 3 of our paper, coupled model simulations are fundamentally different from AMIP runs. A coupled model is NOT driven by observed changes in SSTs, and therefore would not have (except by chance) the same SST changes as the real world over a specific period of time. Stratifying the coupled model results by the observed surface temperature changes is not a meaningful or useful thing to do, particularly given the small ensemble sizes available here. Again, if Douglass et al. were truly interested in imposing "the critical condition that the model surface temperatures match the observations", they should have examined AMIP runs, not coupled model results. I also note that, although Douglass et al. stipulate their "critical condition that the model surface temperatures match the observations", they do not actually perform any stratification of the model trend results! In other words, Douglass et al. do NOT discard simulations with surface trends that differ from the observed trend. They simply note that the MODEL AVERAGE surface trend is close to the observed surface trend, and state that this agreement in surface trends allows them to evaluate whether the model average upper air trend is consistent with observed upper air trends. The Douglass et al. "Addendum" does nothing to clarify the serious statistical flaws in their paper. Their conclusion - that modelled and observed upper air trends are inconsistent - is simply wrong. As we point out in our paper, Douglass et al. reach this incorrect conclusion by ignoring uncertainties in observed and modelled upper air trends arising from interannual variability, and by applying a completely inappropriate "consistency test". Our Figure 5 clearly shows that the Douglass et al. "consistency test" yields incorrect results. The "Addendum" does not suggest that the authors are capable of recognizing or understanding the errors inherent in either their "experimental method" or their "consistency test". The Douglass et al. IJoC paper reached a radically different conclusion from the conclusions reached by Santer et al. (2005), the 2006 CCSP report, the 2007 IPCC report, and Thorne et al. (2007). It did so on the basis of essentially the same data used in previous work. Most scientists would have asked whether the "consistency test" which yielded such startlingly different conclusions was appropriate. They would have applied this test to synthetic data, to understand its behaviour in a controlled setting. They would have applied alternative tests. They would have done everything they possibly could to examine the robustness of their findings. Douglass et al. did none of these things. I will ask Leo Haimberger and Peter Thorne to respond to you regarding the first issue raised in the Douglass et al. "Addendum". Best regards, Ben Santer (* In their addendum, Douglass et al. erroneously refer to "ROABCORE" datasets. One would hope that they would at least be able to get the name of the dataset right.) g.mcgregor@auckland.ac.nz wrote: > 10-Apr-2008 > > JOC-08-0098 - Consistency of Modelled and Observed Temperature Trends in the Tropical Troposphere > > Dear Dr Santer > > Just to let you know that I am trying to secure reviews of your paper asap. > > I have attached an addendum for the Douglass et al. paper recently sent to me by David Douglass. I would be interested to learn of your views on this > > > Best, > > Prof. Glenn McGregor -- ---------------------------------------------------------------------------- Benjamin D. Santer Program for Climate Model Diagnosis and Intercomparison Lawrence Livermore National Laboratory P.O. Box 808, Mail Stop L-103 Livermore, CA 94550, U.S.A. Tel: (925) 422-2486 FAX: (925) 422-7675 email: santer1@llnl.gov ---------------------------------------------------------------------------- | |||