城市化对长三角地区极端气温影响的时空分异研究

Effect of Urbanization on Spatial and Temporal Variation of Extreme Temperature Events in the Yangtze River Delta

论文利用长三角地区65个气象站1960—2014年日最高、最低气温资料,分析并比较了大城市站、一般城市站和乡村站极端气温指数变化趋势以及城市化对大城市站和一般城市站各极端气温指数趋势变化的影响。结果表明:极端气温暖指日数明显增加,冷指日数明显减少,极值指数呈微弱上升趋势。暖指数城市站比乡村站增加趋势明显,冷指数城市站比乡村站减少趋势明显。除月最低气温极小值外,其他极值指数变化趋势在城市、乡村间差异较小。大城市站冰冻日数、霜冻日数、冷(暖)昼日数和月最低气温极小(大)值城市化影响显著,一般城市站冰冻日数、霜冻日数和月最低气温极小值城市化影响显著,城市化对极端气温影响明显的是长三角北部、江苏南部和浙东南的部分城市站点。冷昼日数城市化效应在冬季较明显,暖昼(夜)日数城市化效应在夏季较明显,春季、夏季、冬季城市化对极值指数的影响显著。

The research analyzes the urbanization effect on spatial and temporal trends of indices of extreme temperature using daily maximum and minimum temperature at meteorological stations in big cities, general cities and villages in the Yangtze River Delta region from 1960 to 2014. The results show that the extreme warm indices increased, while the extreme cold indices decreased. There are slight increasing trends of extreme temperature indices. The warm indices increased more distinctly at urban stations than at rural stations, and the cold indices decreased more apparently at urban stations than at rural stations. The tendencies of other extreme value indices have little difference between urban stations and rural stations except for the minimum value of monthly minimum temperature. Urbanization caused significant decreases of ice days （-0.37 d/10 a）, frost days （-1.53 d/10 a） and cold days （-1.05 d/10 a） and significant increases of warm days （1.26 d/10 a）, the minimum value of monthly minimum temperature （0.15 ℃/10 a） and the maximum value of monthly minimum temperature （0.06 ℃/10 a） in big cities. The urbanization effect on the trends of ice days （-0.29 d/10 a）, frost days （-1.27 d/10 a） and the minimum value of monthly minimum temperature （0.12 ℃/10 a） is significant in general cities. The effect of urbanization on extreme temperature indices is evident in the northern Yangtze River Delta, the southern Jiangsu and southeast Zhejiang. The effect of urbanization on the trend of cold days is more significant in winter, and on the trend of warm days （nights） is more significant in summer. The effect of urbanization on the trends of extreme value indices are significant in spring, summer and winter.