Here are a few plots of Jones et al 1990 China urban vs rural sites. Maybe one of our more computer-oriented people could make a little applet to yield 42 comparisons from the small data set which is now collated. For now, here are some very quick and non-prettied up comparisons. I started with a couple of sites in western China because of the recent discussion of Dulan junipers. This is also useful because the leverage on these remote sites is very great because there are few observations and they affect large areas through the Jones gridcell methodology. (One thing to keep in mind with the Jones et al 1990 comparison is that it is only from 1954-1983, when there was much turmoil in China and that there is little trend in many stations. Chinese station temperatures took off more recently.)
First here is Xining (on the road from Lanzhou to Dulan) versus unidentified “rural” WMO station 53161. In this case, there is a pronounced trend in the urban centre while the rural centre is unchanged. Does this mean that there is a UHI trend in Xining? Note that the rural station is warmer than the urban station here.
Next here is a comparison of the two most remote western sites in the J90 comparison. There is somewhat of a trend in the urban site; whether the “rural” site has a trend or merely multidecadal volatility cannot be determined on the graph, but there is a difference between the two.
Steve Sadlov mentioned Guangzhou. Here’s a plot of the Guangzhou comparison to Heyuan. In this case, the “rural” location increased while Guangzhou remained relatively unchanged. Is Heyuan an example of exurban development?
Some of the comparisons look like there must have been some site change that is unaccounted for. For example, consider this graph where two series cross over. In this case, the “rural” station appears to warm while the city cools. Does this make sense?
Here’s another comparison where the urban center shows cooling, while the rural comparandum remains unchanged. It looks as though there might be some non-homogeneity in the urban series in the early part, where it moved to a cooler location without being adjustment. In this particular case, this results in a reduction of the urban-rural UHI differential.
Having looked at all these series, my overall impression is one that this is very thin gruel to be using in big reports. This is supposed to be the best and the brightest?