In case you missed it, on Sunday Dr. Roger Pielke Sr.wrote a statement of support for Watts et al 2012. See: Comments On The Game Changer New Paper “An Area And Distance Weighted Analysis Of The Impacts Of Station Exposure On The U.S. Historical Climatology Network Temperatures And Temperature Trends” By Watts Et Al 2012
Today he has written another essay, showing that Watts et al 2012 and another recent paper, McNider et al 2012 have shown
“…evidence of major systematic warm biases in the analysis of multi-decadal land surface temperature anomalies by NCDC, GISS, CRU and BEST.”
- One paper [Watts et al 2012] show that siting quality does matter. A warm bias results in the continental USA when poorly sited locations are used to construct a gridded analysis of land surface temperature anomalies.
- The other paper [McNider et al 2012] (pdf here) shows that not only does the height at which minimum temperature observations are made matter, but even slight changes in vertical mixing (such as from adding a small shed near the observation site, even in an otherwise pristine location) can increase the measured temperature at the height of the observation. This can occur when there is little or no layer averaged warming.
Read the entire essay here