近50a西北干旱区极端降水的时空变化特征

Spatial and Temporal Variability of the Extreme Precipitation in the Arid Region of Northwest China during Recent 50 Years

利用西北干旱区1961—2010年76个测站的逐日降水量,采用线性趋势,MannKendall(M-K)突变检验等现代统计诊断方法,研究我国西北干旱区极端降水的时空变化特征。结果表明:(1)过去50 a北疆地区和天山山区极端降水量总体上呈增加趋势,河西—阿拉善地区变化不明显;(2)除南疆地区外,北疆、天山山区、河西—阿拉善地区极端降水量分别于1982年、1990年、1987年发生显著的上升突变;(3)极端降水量空间分布的区域差异性显著,在研究区西部表现为以天山山区大值为中心,呈现北高南低的特点;研究区的东部主要是自东南向西北递减的特点;(4)极端降水频率与极端降水量的空间分布基本一致。

In this study, we analyzed the spatial and temporal characteristics of the extreme precipitation and their variability in the arid area of northwest China by using daily precipitation data from 76 stations from 1961 to 2010 and applying linear regression, Mann-Kendall（MK）method. The results showed as follows.（1）The extreme precipitation in the northern Xinjiang and Tianshan Mountains over the past 50 years generally showed an increasing trend while Hexi-Alashan region did not change significantly.（2）Extreme precipitation in the region of the northern Xinjiang, Tianshan Mountains and Hexi-Alashan has significant increase mutation in 1982, 1990,1987 respectively while the southern Xinjiang region does not show significant increasing;（3）Regional distribution difference of extreme precipitation is remarkable. The largest value of extreme precipitation was located in the center of the Tianshan Mountains and northern Xinjiang is higher than that in the southern Xinjiang. In Hexi-Alashan region, there is a decreasing trend dominated from southeast to northwest.（4）The frequency of extreme precipitation has the same spatial distribution.