Guest post by Bob Tisdale
My blog post October to December 2011 NODC Ocean Heat Content Anomalies (0-700Meters) Update and Comments was cross posted by at WattsUpWithThat here. (As always, thanks, Anthony.) Starting at the January 27, 2012 at 8:44 am comment by J Bowers, I was informed of a critique of my ARGO-era model-data comparison graph by the Tamino titled Fake Predictions for Fake Skeptics. Oddly, Tamino does not provide a link to my post or the cross post at WattsUpWithThat, nor does Tamino’s post refer to me by name. But I believe it would be safe to say that Tamino was once again commenting on my graph that compares ARGO-era NODC Ocean Heat Content data to the climate model projection from Hansen et al (2005), “Earth’s energy imbalance: Confirmation and implications”. If he wasn’t, then Tamino fooled three persons who provided the initial comments about Tamino’s post on the WUWT thread and the few more who referred to Tamino’s post afterwards. The ARGO-era graph in question is shown again here as Figure 1. Thanks for the opportunity to post it once again up front in this post, Tamino.
Take a few seconds to read Tamino’s post, it’s not very long, and look at the graphs he presented in it.
My graph in Figure 1 is clearly labeled “ARGO-Era Global Ocean Heat Content Model-Data Comparison”. The title block lists the two datasets as NODC/Levitus et al (2009) and Hansen et al (2005) Model Mean Trend. It states that the Model Mean Trend and Observations had been Zeroed At Jan 2003. Last, the title block lists the time period of the monthly data as January 2003 to December 2011.
In other words, my graph in Figure 1 pertains to the ARGO-based OHC data and the GISS model projection starting in 2003. It does not represent the OHC data or the GISS model hindcast for the periods of 1993-2011 or 1955-2011, which are the periods Tamino chose to discuss.
Do any of the graphs in Tamino’s post list the same information in their title blocks? No. Do any of Tamino’s graphs compare the climate model projection from Hansen et al (2005) to the NODC OHC observations? No. Does Tamino refer to Hansen et al (2005) in his post? No. Do any of Tamino’s graphs present the NODC OHC data or the Hansen et al model projection during the ARGO-era, starting in January 2003 and ending in December 2011? No.
In other words, Tamino redirected the discussion from the ARGO-era period of 2003-2011 to other periods starting in 1955 and 1993. ARGO floats were not in use in 1955 and they were still not in use in 1993. He also redirected the discussion from the projection of the GISS model mean to the linear trend of the data itself. Yet Tamino’s followers fail to grasp the obvious differences between his post and my ARGO-era graph.
In my post, I explained quite clearly why I presented the ARGO-era model-data comparison with the data zeroed at 2003. Refer to the discussion under the heading of STANDARD DISCUSSION ABOUT ARGO-ERA MODEL-DATA COMPARISON. Basically, Hansen et al (2005) apparently zeroed their model mean and the NODC OHC data in 1993 to show how well their model matched the OHC data from 1993 to 2003. Hansen et al explained why they excluded the almost 40 years of OHC and hindcast data. The primary reason was their model could not reproduce the hump in the older version of the Levitus et al OHC data. Refer to Figure 2, which is a graph from a 2008 presentation by Gavin Schmidt of GISS. (See page 8 of GISS ModelE: MAP Objectives and Results.) I presented that same graph graph by Gavin in my post GISS OHC Model Trends: One Question Answered, Another Uncovered, which was linked in my OHC update from a few days ago.
I zeroed the data for my graph in 2003, which is the end year of the Hansen et al (2005) graph, to show how poorly the model projection matched the data during the ARGO-era, from 2003 to present. In other words, to show that the ARGO-era OHC data was diverging from the model projection. Hansen et al (2005), as the authors of their paper, chose the year they apparently zeroed the data for one reason; I, as the author of my post, chose another year for another reason. I’m not sure why that’s so hard for Tamino to understand.
And then there’s Tamino’s post, which does not present the same comparison. He did, however, present data the way he wanted to present it. It’s pretty simple when you think about it. We all presented data the way we wanted to present it.
Some of the readers might wonder why Tamino failed to provide a similar ARGO-era comparison in his post. Could it be because he was steering clear of the fact that it doesn’t make any difference where the model projection intersects with the data when the trends are compared for the ARGO-era period of 2003 to 2011? See Figure 3. The trend of the model projection is still 3.5 times higher than the ARGO-era OHC trend. Note that I provided a similar graph to Figure 3 in my first response to his complaints about that ARGO-era OHC model-data comparison. See Figure 8 in my May 13, 2011 post On Tamino’s Post “Favorite Denier Tricks Or How To Hide The Incline”.
Figure 3 shows the ARGO-era OHC data diverging from the model projection. But the visual effect of that divergence is not a clear as it is in Figure 1. I presented the data in Figure 1 so that it provided the clearest picture of what I wanted to show, the divergence. That really should be obvious to anyone who looks at Figure 1.
Some might think Figure 1 is misleading. The reality is, those illustrating data present it so that it provides the best visual expression of the statement they are trying to make. The climate model-based paper Hansen et al (2005) deleted almost 40 years of data and appear to have zeroed their data at 1993 so that they could present their models in the best possible light. Base years are also chosen for other visual effects. The IPCC’s Figure 9.5 from AR4 (presented here as Figure 4) is a prime example. Refer to the IPCC’s discussion of it here.
The Hadley Centre presents their anomalies with the base years of 1961-1990. Why did the IPCC use 1901-1950? The answer is obvious. The earlier years were cooler and using 1901-1950 instead of 1961-1990 shifts the HADCRUT3 data up more than 0.2 deg C. In other words, the early base years make the HADCRUT anomaly data APPEAR warmer. It also brings the first HADCRUT3 data point close to a zero deg C anomaly, and that provides another visual effect: the normalcy of the early data.
Base years for anomalies are the choice of the person or organization presenting the data. Climate modelers choose to present their models in the best light; I do not.
Those familiar with the history of Tamino’s complaints about my posts understand they are simply attempts by him to mislead or misdirect his readers. And sometimes he makes blatantly obvious errors like using the wrong sea surface temperature dataset in a comparison with GISS LOTI data. His post Fake Predictions for Fake Skepticsis just another failed critique to add to the list.
The NODC OHC data used in this post is available through the KNMI Climate Explorer: