近51 a甘肃夏季气温和降水极端事件变化

利用1960-2010年甘肃35站夏季（6-8月）逐日观测资料，分析暴雨、干燥和异常温度事件的变化特征。结果表明：近51 a甘肃河西区暴雨基本稳定在0.1次/a左右,而河东区在20世纪70年代中期前为显著下降趋势，之后其变化趋势不显著。两区暴雨事件的强度变化均不显著,但在时间上分布比较分散，80年代中期之后暴雨事件发生的时段较之前提前了约2候；河东、河西区的严重干燥事件频次均在1991年发生突变，突变后的显著增加主要是受降水日数在同期突变后显著减少的影响；异常高、低温频次均在90年代中期发生突变，突变后异常高温频次显著增加，异常低温频次显著减少。

Change of Extreme Temperature and Precipitation Events in Gansu Province in Summer in Recent 51 Years

In this paper, the characteristics and trends of rainstorm events, severe drought events and anomalous maximum and minimum temperature events were investigated based on the daily data observed by 35 meteorological stations in Gansu Province and the reanalysis monthly data in summer (from June to August) during the period from 1960 to 2010, and the data were derived from National Climate Center and National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). The main results show that the absolute intensity of rainstorm was lower than the relative intensity. The frequency of rainstorm events in summer was about 0.1 time a year in the Hexi Corridor in recent 51 years. In the Hedong region, however, the rainstorm frequency was in a decrease trend before the mid-1970s, and then the change trend was not significant. The variation of rainstorm intensity in these two areas was not significant, and the seasonal distribution was relatively dispersed. Rainstorm events occurred 10 days earlier compared with that after the mid 1980s. Severe drought events were sharply increased from 1991. The frequency of extremely high temperature was significantly increased but that of extremely low temperature decreased from the mid-1990s.