There is a new paper out in Geophysical Research Letters: Wen, H. Q., X. Zhang, Y. Xu, and B. Wang (2013), Detecting human influence on extreme temperatures in China, Geophys. Res. Letters, 40, doi:10.1002/grl.50285.
Heat Extremes in ChinaAn excerpt from the news release:
WASHINGTON – Humans are responsible for increasingly warm daily minimum and maximum temperatures in China, new research suggests. The study is the first to directly link greenhouse gas emissions with warmer temperature extremes in a single country, rather than on a global scale, according to the paper's authors.
"There is a warming in extreme temperatures over China, and this warming cannot be explained by natural variation," said Qiuzi Han Wen, an author on this paper and a researcher at the Institute of Atmospheric Physics in Beijing, China. "It can only be explained by the anthropogenic external forcings. These findings indicate very clearly that climate change is not just an abstract number for the globe; it is evident at regional scale."
Watts' UHI FixationAnthony Watts writes - you guessed it:
But the only forcing they considered was GHG’s. Nary a word exists in the paper about UHI, urban heat island, station siting, of heat sync (sic) effects.It's true that the paper doesn't mention UHI. It's likely that is already taken into account as part of the quality control to which the paper refers:
China’s National Climate Center has recently compiled and quality controlled an extensive daily temperature data set [Wu and Gao, 2012]. Records of daily maximum, daily minimum, and daily mean temperatures were collected from 2416 observation stations from 1961 to 2007.Thing is, if Anthony was correct and the quality control process for some reason omitted to allow for UHI, would one expect the greatest increase in extreme temperatures to be in areas of greatest population growth?
Compare the MapsNow the maps I've come across don't show population growth but they do show population density. Let's just look at the maps and compare them to the charts showing trends in the maxima (Tx) and minima (Tn) temperatures in the paper (click images to enlarge).
Should we let Anthony know that the population maps of China must be wrong?