Extreme Temperature Occurrences in China: 1961-2008
Zhou, Y. and Ren, G. 2011. Change in extreme temperature event frequency over mainland China, 1961-2008. Climate Research 50: 125-139.
In discussing their fingings, Zhou and Ren say that "urbanization intensified the downward trend in cold index series and the upward trend in warm indices related to minimum temperature." More specifically, they report that "the urbanization effect on the series of extreme temperature indices was statistically significant for the downward trends in frost days, daily temperature range, cool nights, and cool days," as well as for "the upward trends in summer days, tropical nights, daily maximum temperature, daily minimum temperature, and warm nights." And for these indices, they say that "the contributions of the urbanization effect to the overall trends ranged from 10 to 100%, with the largest contributions coming from tropical nights, daily temperature range, daily maximum temperature and daily minimum temperature," adding that "the decrease in daily temperature range at the national stations in North China was caused entirely by urbanization."
Speaking of urbanization or the urban heat island phenomenon, the two researchers concluded their paper by stating that "more attention needs to be given to the issue in future studies," which is something that IPCC contributors and reviewers have refused to do.
Zhou, Y.Q. and Ren, G.Y. 2009. The effect of urbanization on maximum and minimum temperatures and daily temperature range in North China. Plateau Meteorology 28: 1158-1166.