中国西北东部降水量变化的空间分布及突变特征分析

摘 要：为了解西北东部降水变化特征，为应对气候贫困实施扶贫战略提供理论依据，利用1961—2010年中国西北东部81站降水资料，采用气候趋势、相关系数、相对变率、Mann-Kendall等方法，对西北东部降水的变化特征进行分析。结果表明：近50年来，年降水量显著减少区在陕西东部边界附近、甘肃岷县—临洮—华家岭、宁夏固原一带，增加区在德令哈—都兰—托勒区域；春季降水量显著减少区在陕西中东部、南部，增加区在青海中东部、西南部；夏季降水量显著减少区在河西走廊西端，增加区在青海中西部、北部、陕西南部；秋季降水量显著减少区在陕西南部、宁夏中南部、甘肃东南部，增加区在青海西北部、甘肃西部；冬季降水量（除个别站点外）均为增加趋势。季节降水量的相对变率与年的分布类似，高值区在青海西北部、河西走廊西端，低值区在祁连山区及青海南部、陕西南部。近50年秋、冬季降水量发生突变，判断可能的突变点分别是1975年、1986年。

Precipitation Change in Eastern Part of Northwest China: Spatial Distribution and Mutation Characteristics

To understand the variation characteristics of precipitation in the eastern part of northwest China, and to provide a theoretical basis for the implementation of poverty alleviation strategies in response to climate poverty, based on the precipitation data of 81 stations in eastern part of northwest China from 1961 to 2010, the authors analyzed the variation characteristics of precipitation in the area by using the climate trends, correlation coefficient, relative variability, Mann- Kendall and other methods. The results showed that: in recent 50 years, the annual precipitation significantly reduced in the eastern border of Shaanxi, Minxian- Lintao-Huajialing in Gansu and Guyuan in Ningxia, and the increased area was located in Delingha-Dulan- Tuole; the precipitation in spring significantly reduced in the middle, east and south of Shaanxi, the increasedarea was located in the middle, west and southwest of Qinghai; the precipitation in summer significantly reduced in western Hexi corridor, the increased area was located in the middle, west and north of Qinghai and southern Shaanxi; the precipitation in autumn significantly reduced in southern Shaanxi, the middle and south of Ningxia, southeastern Gansu, the increased area was located in northwestern Qinghai and western Gansu; the precipitation in winter was increasing (excepted for individual sites); the relative variability of seasonal precipitation was similar to that of the annual precipitation, the high value area was in northwestern Qinghai, the western Hexi corridor, and the low value area was in Qilian Mountains, southern Qinghai and southern Shaanxi; the precipitation in autumn and winter had mutations in the 50 years, the possible points of mutation were determined in 1975 and 1986.