1960-2009年青海省极端降水事件的变化特征

Changes of Extreme Precipitation Events in Qinghai Province During 1960-2009

利用1960-2009年青海省26个气象台站的降水资料,采用线性倾向估计法、反距离加权法、M—K突变检测等方法,研究了青海省50a来极端降水事件变化的空间分布以及时间变化特征。结果发现,近50a来,青海省极端降水天数、最大的1d和5d降水总量、中雨天数和逐年平均降水强度均表现为增加(强)趋势,只有极端降水天数通过了0.05的置信度检验;各极端降水指数变化趋势存在空间差异,祁连山地区极端降水天数、最大的1d和5d降水总量、中雨天数和逐年平均降水强度增加趋势明显,青海省东部地区增加不明显或呈微弱减少趋势;青海省极端降水事件在0.05的置信度下发生了明显的突变现象,且各极端降水指标与年降水总量有很好的相关性。

Based on daily and annual precipitation recorded at twenty-six meteorological stations in Qinghai Province from 1960 to 2009, regression analysis, inverse distance weighted method and Mann--Kendall method were employed to analyze the spatial and temporal variability in extreme precipitation events. The re- suits indicated that extreme precipitation days, annual maximum 1 d precipitation, annual maximum consecu- tive 5 d precipitation, very heavy precipitation days and daily rainfall intensity showed increasing trends in the recent 50 years, and only the extreme precipitation days were significant at the 0.05 level. The spatial change of precipitation extreme events in the study area showed that extreme precipitation days, annual max- imum 1 d precipitation, annual maximum consecutive 5 d precipitation, very heavy precipitation days and dai- ly rainfall intensity in Qilian Mountains had statistically increasing trends while they increased or decreased insignificantly in eastern region. In addition, it was also found that abrupt changes presented in precipitation extreme events at the 0.05 level. At the same time, there were significant correlations between annual total precipitation and different precipitation indices.