Guest post by Bob Tisdale
For years, Tamino (aka Grant Foster) has complained about the placement of the GISS model projection at the start of the ARGO-era OHC data. Well, Gavin just discovered an error in his presentation of the GISS model simulations. And he’s corrected them. Funny how, if we only looked at the ARGO era, the new GISS model-data comparisons would now resemble mine. So I acknowledged, and thanked Gavin–and then showed his graphs.
NOW Will Tamino Correct his Posts?
Tamino has complained about my model-data presentation of ARGO-era Global Ocean Heat Content in numerous posts. See here and here, and my replies here and here. My replies were also cross posted at WattsUpWithThat here and here. Tamino didn’t like the point where I showed the model projections intersecting with the Ocean Heat Content data. Refer to Figure 1.
A few months ago, Gavin Schmidt of GISS also suggested that my presentations were wrong in his 2011 Updates to model-data comparisons. There he wrote [my boldface]:
As an aside, there are a number of comparisons floating around using only the post 2003 data to compare to the models. These are often baselined in such a way as to exaggerate the model data discrepancy (basically by picking a near-maximum and then drawing the linear trend in the models from that peak). This falls into the common trap of assuming that short term trends are predictive of long-term trends – they just aren’t (There is a nice explanation of the error here).
(That language, by the way, still exists in his updated post even though he has corrected his data.)
Gavin missed the point that I wasn’t interested in presenting long-term trends in that graph. That aside, today, Gavin Schmidt issued a correction to his presentations of Ocean Heat Content in his model-data comparisons. Gavin writes:
This is just a brief note to point out that a few graphs that I have put together showing Ocean Heat Content changes in recent decades had an incorrect scaling for the GISS model data. My error was in assuming that the model output (which were in units W yr/m2) were scaled for the ocean area only, when in fact they were scaled for the entire global surface area (see fig. 2 in Hansen et al, 2005). Therefore, in converting to units of 1022 Joules for the absolute ocean heat content change, I had used a factor of 1.1 (0.7 x 5.1 x 365 x 3600 x 24 x 10-8), instead of the correct value of 1.61 (5.1 x 365 x 3600 x 24 x 10-8). This problem came to light while we were redoing this analysis for the CMIP5 models and from conversations with dana1981 at skepticalscience.com.
That error was similar one Roger Pielke Sr. had made in one of his Ocean Heat Content posts, an error that Roger corrected almost a year ago.
Gavin went back and corrected the graphs in his earlier model-data comparisons at RealClimate. Thanks for the corrections, Gavin. I’ve been suggesting that your presentations were wrongfor a while now.
So what do the new RealClimate model-data comparison graphs look like for Ocean Heat Content?
From today’s post:
From the update for 2011:
From the update for 2010:
And from the 2009 update:
If we were to look at only the data since 2004, the RealClimate graphs would look very similar to mine shown in Figure 1. In fact, I may have to shift the model projection a little to the left in my graphs.
I wonder if Tamino will continue his nonsensical claims about my ARGO-era presentations and whether he will correct the posts at his blog. If history repeats itself, Tamino won’t.
Thanks to Bill Illis for notifying me of the RealClimate corrections.
MY FIRST BOOK
The IPCC claims that only the rise in anthropogenic greenhouse gases can explain the warming over the past 30 years. Satellite-based sea surface temperature disagrees with the IPCC’s claims. Most, if not all, of the rise in global sea surface temperature is shown to be the result of a natural process called the El Niño-Southern Oscillation, or ENSO. This is discussed in detail in my first book, If the IPCC was Selling Manmade Global Warming as a Product, Would the FTC Stop their deceptive Ads?, which is available in pdf and Kindle editions. An overview of my book is provided in the above-linked post. Amazon also provides a Kindle preview that runs from the introduction through a good portion of Section 2. That’s about the first 15% of the book. Refer also to the introduction, table of contents, and closing in pdf form here.