青藏高原中东部夏季极端降水年代际变化特征

基于中国国家级地面气象站基本气象要素日值数据集得到的均一化降水序列,计算了夏季极端降水指数,分析青藏高原中东部1961—2014年夏季极端降水年代际变化趋势。结果表明:青藏高原中东部地区夏季降水量占全年总降水的50%以上,且夏季降水的变化趋势存在区域性差异,北部站点主要为增加趋势,南部增加和减少趋势的站点相当。夏季极端降水除西藏东部主要为减少趋势外,其他地区主要为增加趋势,且极强降水量的年代际变化趋势显著。大部分夏季极端降水指数的变化趋势在1970s发生转折,在此之前表现为减少的趋势,之后为增加趋势。通过Mann-Kendall趋势检验,在2000年之后强降水量和极强降水量出现突变。

Interdecadal characteristics of the summer extreme precipitation in the central and eastern Tibetan Plateau

Based on the homogenized basic meteorology historical precipitation dataset in the eastern and central Tibetan Plateau (TP) and the summer extreme precipitation indices, the interdecadal characteristics of the temporal and spatial distribution and variation tendencies of summer extreme precipitation were analyzed during 1961 to 2014. The results showedthat summer precipitation contributed more than 50% to annual total precipitation with a regional difference and an increase tendency is in the northern TP and half stations have increased in the southern TP. Summer extreme precipitation indices showed an increase tendency except for the eastern TP, and extremely wet day precipitation (R99) had a significant increase tendency. Majority of summer extreme precipitation indices reduced before the 1970s, and turn to increase afterward. Furthermore, the turning point years detected by the Mann-Kendal method of very wet day precipitation (R95) and R99 appeared after 2000.