The change and urbanization effect on extreme temperature trends in the Yangtze River Basin

This article examines the impact of urbanization on extreme temperature trends as estimated from 658 national ground meteorological observation stations in the Yangtze River Basin over the past 60 years. The main findings include: ①The annual mean, maximum, and minimum temperatures all display a significant upward trend, accompanied by a decline in diurnal temperature range (DTR) and corresponding changes in extreme warm/cold indices. ② Urbanization had a substantial impact on trends of the extreme temperatures in the Yangtze River Basin, particularly evident in the two decades after 2000. Apart from the maximum temperature and DTR, urbanization contribution to the trends of most extreme indices are around 10–30%. ③ Large urbanization effect predominantly occurs in the middle-lower reaches, while the upper Yangtze River area witnesses a compressed urbanization effect, which may have been related to altitude-dependent warming and the relatively slow urbanization around the stations.