西南地区可降水量时空分布和变化特征

利用NCEP 1980-2009年可降水量的逐月再分析资料,分析了30年来西南地区可降水量的时空分布特征和变化趋势.结果表明：受地形等地理环境和气候的影响,西南地区年、季节可降水量分布均有显著的地区性差异,东南多,西北少；可降水量的季节变化明显,夏季远大于冬季,秋季略高于春季；可降水量的年内分配不均,7月最大,8月次之,1月最少；30年来,西南地区年可降水量呈波动变化,略有增加,偏多和偏少年交替出现,春季和冬季可降水量呈线性增多.西南地区可降水量空间分布既有整体一致型,也存在反向型.

Distribution and Variation of Precipitable Water in Southwest China

The spatial and temporal distributive characteristics and variation trends of precipitable water in the southwest area are analyzed by using NCEP monthly precipitable water data from 1980 to 2009. The results show that influenced by geographical environment and climate, the distribution of annual and seasonal precipitable water in Southwest China has obvious regional difference, greater in the southeast and less in the northwest. Precipitable water varies with season obviously, with the value in summer being visibly higher than that in winter, and that in autumn slightly higher than that in spring. The annual distribution of precipitable water is uneven： the greatest precipitable water appearing in July, the secondary in August, and the least in January. Around the recent 30 years, the annual precipitable water in the southwest fluctuates alternately. There is an upward trend in annual precipitable water, as well as in spring and winter. The spatial distribution of annual precipitable water exhibits not only consistency in the whole area, but also reverse patterns.