陇东塬区不同量级降水的气候变化特征

Climatic Changes of Different Level Precipitation in the East of Gansu Province

利用西峰站1951～2010年逐日降水观测资料，根据划分的雨量级别分析了近60a来陇东塬区西峰年降水量及分级降水雨量谱的气候变化特点，并利用累积距平法和Mann—Kendall方法对气候突变进行分析检测。结果表明，近60a西峰的年降水量有明显的下降趋势，其中小雨、中雨、大雨均为正贡献，暴雨为负贡献。而1986—2010年期间年降水有弱的上升，主要是大雨级的雨量增大、雨日增多和雨强增强所致；进一步分析得出，上述变化仍属于年际变化范畴，因此不能说突变已经发生，但有上升迹象。

Using the daily precipitation observational data at Xifeng meteorological station located in the east of Gansu Province from 1951 to 2010, the climate change characteristics of the precipitation and its spectrum in recent 60 years were analyzed, and the climate mutation of precipitation was detected by using cumulative anomaly and Mann - Kendall test. The results show that the annual precipi- tation presented an obviously decreasing trend, and light, moderate and heavy rain had positive contribution to the total rainfall, while rainstorm had negative contribution in recent 60 years. The annual precipitation displayed a weak increasing trend during 1986 -2010 due to the increasing rainfall, increasing rain days and enhancing rainfall intensity of heavy rain. These changes still belong to the cate- gory of annual variation. Therefore, it is believed that the mutation of precipitation hadn＇ t occurred yet, but the precipitation since 1986 showed increasing signs.