金沙江流域中上游近10年降水时空分布特征分析

Spatial and Temporal Distribution Characteristics of Precipitation over the Past 10 Years in the Middle and Upper of Reaches of Jinsha River Basin

摘要: 对金沙江流域中上游地区进行近10年降水量EOF分析中，年降水量前3个载荷量的累计方差贡献已经达到83.47%，且第一模态的方差贡献率就已经达到68.86%；干湿季降水量前3个载荷量的累计方差贡献已经达到95.77%，且第一模态的方差贡献率就已经高达92.2%，四季降水量前3个模态的方差贡献率其载荷量的累计方差贡献已经达到93.77%，第一个模态的方差贡献率高达89.91%。所以近10年，年、干湿季及四季降水的第一模态已经能较好的表征该变量场的空间分布及时间分布特征。年、干湿季、四季降水量第一模态空间分布场均为全区均为正值，说明降水量变化一致性为金沙江流域中上游地区年、干湿季、四季降水量变化的主要特征，其中迪庆州南部，丽江市东部地区一带特征值最大，在最具代表性的变化中这些地区降水量变化最敏感，即降水量增加最多或减小最少。金沙江流域中上游地区年、干湿季、四季降水量四季降水量具有一致性，即整个流域中上游段降水量变化是一致的。

Abstract: In the EOF analysis of precipitation in the middle and upper reaches of the Jinsha River Basin over the past 10 years, the ratio of the front 3 eigenvectors with total square error is 83.47% and the variance contribution rate of the first mode has reached 68.86%. The cumulative variance contri- bution of the first three modes of precipitation in the dry and wet seasons has reached 95.77%, and the variance contribution rate of the first mode has been as high as 92.2%. The cumulative variance contribution of the first mode of precipitation of four seasons has reached 93.77%, and the variance contribution rate of the first mode is as high as 89.91%. Therefore, the first mode in the past 10 years, the dry and wet seasons, and the four seasons of precipitation can characterize the spatial and temporal distribution characteristics of the variable field well. The spatial distribu- tion of the first mode of precipitation in the first mode of yearly, dry and wet seasons and four seasons is positive in the whole region, indicating that the consistency of precipitation change is the main characteristic of the change of precipitation in the middle and upper reaches of the Jinsha River Basin, among which the characteristic values of the southern part of Diqing and the eastern part of Lijiang are the largest, and the precipitation variation in these areas is the most sensitive among the most representative changes, that is, the precipitation increases the most or decreases the least. The precipitation in the middle and upper reaches of the Jinsha River Basin is consistent of yearly, dry and wet seasons and four seasons, that is, the precipitation changes in the middle and upper reaches of the basin are consistent.