While reading the Climategate emails, I chanced upon a message to Phil Jones from a Chinese researcher, Yan ZhongWei inquiring if the great man would like to be a co-author on a forthcoming paper.
Hi, Phil,
Attached please find a draft paper about site-changes and urbanization at Beijing. It may be regarded as an extension of our early work (Yan et al 2001 AAS) and therefore I would be happy to ask you to join as a co-author.
Regarding your recent paper about UHI effect in China (no doubt upon a large-scale warming in the region), I hope the Beijing case may serve as a helpful rather than a contradictory (as it may appear so) reference.
The urbanization-bias at BJ was considerable but could hardly be quantified. I suspect it was somehow overestimated by a recent work (Ren et al 2007). Please feel free to comment and revise.
I'll check and complete the reference list, while you may also add in new references
Cheers
Zhongwei
Well if the paper appeared contradictory, showing a substantial UHI, then I wanted to know about it. This appears to be it. Here's the abstract:
During 1977-1981 the Beijing (BJ) meteorological station was at a suburban location. In 1981 it was moved to a more urban location, but in 1997 it was subsequently moved back to the same suburban location. The daily BJ temperature series, together with those from 18 nearby stations, form a unique database for studying how site-change and possible urbanisation influences affect climate changes at a local scale. The site-change-induced biases were quantified, between 0.43 and 0.95°C, based on comparisons between multi-year-mean seasonal temperature anomalies at BJ and the mean of those from a cluster of nearby stations. The annual mean urban-suburban difference was 0.81°C around 1981 and 0.69°C around 1997, indicating a growing urbanisation effect in the suburban compared to the downtown area. The linear warming trend in the adjusted (for site moves only) BJ temperature series during 1977-2006 was 0.78 °C/decade. Comparing with several rural and less-urban sites, we suggest that the BJ records include an urbanisation-related warming bias between 0.20 and 0.54°C/decade, likely about 0.30°C/decade, for the recent few decades. The climatic warming at BJ between 1977 and 2006 is likely, therefore, to be about 0.48°C/decade. Caveats for using these estimates were discussed.