近53年黄河流域降水时空分布特征

利用黄河流域76个气象台站近53 a（1960-2012）的逐日降水资料，采用国际上通用的极端降水事件指数，应用一元线性回归法、移动平均法和径向基函数空间插值法，研究了黄河流域极端降水指数时空变化特征。结果表明：（1）时间上，黄河流域年平均降水量在过去53 a下降趋势较为显著，降水倾向率为-7.2 mm/10a；极端降水量变化趋势表现较为稳定，极端降水倾向率为-0.64 mm/10a，呈不断降低趋势；极端降水强度倾向率为-0.078 mm/10a，呈不断下降趋势；极端降水比率总体表现为微弱增长趋势，倾向率为0.49 mm/10a。（2）空间上，降水量空间分布具有明显的差异性，由北至南呈阶梯式逐渐增多趋势，其中降水量最少的地区是以银川为代表的周边区域，最多的地区为黄河流域南部区域；极端降水量从北至南也具有逐渐增多态势，与降水量具有相似的空间分布特点，且极端降水量越多的地区降水总量也相对较多；极端降水强度表现出由流域西部向东部逐渐增多的趋势，西部最低值为不到20 mm/d，逐渐向东过渡到最大值为76 mm/d；极端降水比率的分布呈由北向南逐渐递减的特点，并且出现了以银川为中心的极大值和以西安为中心的极小值分布格局。

Spatio-temporal characteristics of extreme precipitation event in Yellow River basin in recent 53 a

Based on daily precipitation data of 76 meteorological stations in Yellow River basin from 1960 to 2012,four precipitation indices were calculated, the inter-annual change trends were studied by methods of regression analysis and five years moving average, and spatial distribution characteristics of the precipitation indices were analyzed by radial base interpolation. The results show：（1） In time, In the period of 1960~2012, average annual rainfall were significant descend with the rate of-7.2/10a, extreme precipitation was the same descend trend with the rate of-0.64/10a as intensity of extreme precipitation with the rate of-0.07827/10a, extreme precipitation concentration ratio has increased weakly by the rate of 0.49/10a. （2） In space, the spatial distribution of extreme precipitation indices exhibited notable spatial disparity. Rainfall increased significantly from north to south, and the area with the least rainfall is located in the peripheral region of Yinchuan, the most rainfall in the southern Yellow River Basin. Extreme precipitation showed an increasing trend and the same spatial distribution characteristics as rainfall, and the more extreme precipitation, the more rainfall. Intensity of extreme precipitation had an increasing trend from west to east, and the minimum value of less than 20mm/d in west, maximum value of more than 76mm/d in the east. Extreme precipitation concentration ratio has a decreasing trend from north to south with a maximum value centering on Yinchuan, a minimum value centering on Xi’an city.