Bishop Hill A climategate snippet on urban heat islands
Jan 3, 2010 Climate: CRU Climate: Jones Climate: Surface 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.
Reader Comments (7)
BH! You are a legend. You have found the Mother Lode. Keep digging into delta UHI issues. There is a very big story here.
And what did Phil Jones answer?
This is what Phil Jones wrote in response:
Zhongwei,
Will read soon !
Attached is what I finally submitted to JGR.
Don't pass on to anyone else.
I have also received a paper from Li, Q, but have yet to
read that. He only sent it yesterday.
Cheers
Phil
Dear "Bishop"
Are you aware that the full version of the paper appears to be available as a pdf file?
"Effects of site change and urbanisation
in the Beijing temperature series 1977–2006"
Zhongwei Yan,* Zhen Li, Qingxiang li and Phil Jones
INTERNATIONAL JOURNAL OF CLIMATOLOGY
Int. J. Climatol. (2009)
Published online in Wiley InterScience
(www.interscience.wiley.com) DOI: 10.1002/joc.1971
http://nzc.iap.ac.cn/ewea/images/stories/reference/2009/1/102_yan_lizhen_2009_ijoc_online.pdf
When I "preview post" the url gets cut off. In case you need it, the last half is:
2009/1/102_yan_lizhen_2009_ijoc_online.pdf
Alan
No I wasn't. Thanks for that.
Well done, Bishop! We await more drips of information eagerly!
Fellow Sceptics and Alarmists alike:
Am I the only one to note that, even with the correction, Bejing's temperature rise is 5C* per century? I recognize that the last 40 years is more extreme than previously, and a correction from the cooling episode that had "us" worrying about a new ice age in the 70s. Still, it is a substantial rise, beyond the 1.5C*/century that others have suggested is the natural rebound from the Little Ice Age. Since a 5C* increase is not uniform to the entire year, portions of the year must be significantly hotter than that. From my Canadian praire perspective, such a temperature rise in the growing seasons could hammer agricultural productivity, for wheat in particular. I recall coming back from a weekend trip at harvest to see yellow-headed crop for miles around that resulted from such a spike. This translated into a 20% crop loss to the farmer I was with.