快速城市化对上海代表站降水的影响

Impacts of rapid urbanization on precipitation at two representative rain gauges in Shanghai City

通过比较上海城区代表站洋泾和乡村代表站夏字圩1979—2014年日降水记录,对各降水要素进行对比分析,辨识2000年前后2个站降水阶段性变化规律及其差异,揭示城市化对局地降水的影响特征。结果发现:2000年之后上海城市化进程明显加速,且2000年前后洋泾和夏字圩2个站的降水关系发生了系统变异,降水差异明显扩大。由于洋泾和夏字圩均位于太湖东部平原地区,且台风性降水的阶段变化特征基本一致,因此剥离区域降水变异的影响后,将1979—2014年洋泾站降水表现出异于夏字圩站的阶段性特征主要归因于城市化局地增雨效应,且2000年以来上海快速城市化总体上对城区代表站的降水产生了显著的强化作用,增加了强降水事件发生的概率。

The daily rainfall records for the period of 1979 -2014 from two urban and rural representative rain gauges （ i. e. , Yangjing and Xiaziwei） in Shanghai City were compared, and factors of precipitation at the two rain gauges were analyzed. The influences of urbanization on local precipitation were revealed based on the investigation of the time variability of precipitation at the two rain gauges before and after the year of 2000 and the difference between the two rainfall series. Results show that, with the acceleration of urbanization in Shanghai City since 2000, the relationship between the precipitation at the two rain gauges presents systematic variation before and after 2000, and their differences have become more significant. Considering that the two rain gauges are both located in the eastern plain of the Taihu Basin, with the similar time variability of typhoon precipitation, the differences between the precipitation at the two rain gauges from 1979 to 2014 are mainly attributed to the urbanization-induced local precipitation enhancement without consideration of the regional differences. The rapid urbanization in Shanghai City since 2000 has significantly enhanced the local precipitation at the urban rain gauge and increased the probability of heavy rainfall events.