Sunday, January 24, 2010

The usual Warmist love of partial data

A recent Warmist paper in the Journal of Geophysical Research purports to disprove claims that U.S. temperature-measuring sites are poorly located and thus lead to a "warm bias" in their measurements:
On the reliability of the U.S. Surface Temperature Record

By Matthew J. Menne, Claude N. Williams, Jr., and Michael A. Palecki

Abstract

Recent photographic documentation of poor siting conditions at stations in the U.S. Historical Climatology Network (USHCN) has led to questions regarding the reliability of surface temperature trends over the conterminous U.S. (CONUS). To evaluate the potential impact of poor siting/instrument exposure on CONUS temperatures, trends derived from poor and well-sited USHCN stations were compared.

Results indicate that there is a mean bias associated with poor exposure sites relative to good exposure sites; however, this bias is consistent with previously documented changes associated with the widespread conversion to electronic sensors in the USHCN during the last 25 years. Moreover, the sign of the bias is counterintuitive to photographic documentation of poor exposure because associated instrument changes have led to an artificial negative ("cool") bias in maximum temperatures and only a slight positive ("warm") bias in minimum temperatures.

These results underscore the need to consider all changes in observation practice when determining the impacts of siting irregularities. Further, the influence of non-standard siting on temperature trends can only be quantified through an analysis of the data. Adjustments applied to USHCN Version 2 data largely account for the impact of instrument and siting changes, although a small overall residual negative ("cool") bias appears to remain in the adjusted maximum temperature series.

Nevertheless, the adjusted USHCN temperatures are extremely well aligned with recent measurements from instruments whose exposure characteristics meet the highest standards for climate monitoring. In summary, we find no evidence that the CONUS temperature trends are inflated due to poor station siting.

So how do they arrive at that conclusion? Anybody who has seen pictures of the temperature-measuring sites located right beside artificial heat sources would have to be amazed.

Easy, Peasy! The old warmist trick of using only part of the data. They took their data from a preliminary list of sites published by the skeptical blog SurfaceStations.org. But that list included less than 50% of the actual temperature-measuring sites. The list is presently up to 82% but the authors of the blog are waiting for it to reach 100% so that they can publish a full analysis. Some temperature stations are easier to get at than others so there is no reason to believe that the preliminary list is representative of the whole. Another problem with the preliminary list is that the categorization of stations as "good" or "bad" was also preliminary and hence wrong in some instances. The number of temperature-measuring sites that conform to official guidelines about where they should be located is actually quite small so the preliminary list was too optimistic about that. I hear informally that the nearly-complete data is showing a very different picture from that described above.

Amusing, though, that scientific journals are now accepting skeptical blogs as a source of data. The worm certainly is turning. I might also mention something that only academics would know: The publication of the above paper gives the skeptical scientists an excellent "hook" to hang their own paper on and more or less ensures that their paper will be accepted for publication in the same journal. Given the general resistance to publishing skeptical papers, that is very handy. It is a rare case of the crooks making it easier for honest men.

And when I say "crooks" I mean it quite literally. It is generally regarded in scientific circles as highly unethical to "jump the gun" -- i.e. to publish analyses of someone else's data before they have had a chance to publish it themselves. But who expects ethics of Warmists?

Posted by John Ray (M.A.; Ph.D.).

No comments:

Home

eXTReMe Tracker