青海高原夏季降水异常及其水汽输送特征分析

Analysis of Summer Precipitation Anomaly and Water Vapor Transport in Qinghai Plateau

通过对青海高原夏季降水异常及其水汽输送特征的分析表明：（1）青海高原夏季降水的年代际变化总体呈先增后减的抛物线型变化，80年代中期以前没有明显的变化周期，80年代末以后存在较稳定的3年周期，目前正处于一相对多雨时期。（2）青海高原夏季整层水汽通量在50-150kg·m^-1·s^-1之间，自西界向东界增加，近43年空中水汽收支整体上呈增加趋势。（3）旱年青海高原空中水汽偏少10-40kg·m^-1·s^-1，水汽通量散度场除北部呈辐合加强外，其余地区均为水汽通量辐散加强区。涝年青海高原水汽输送偏强10-20kg·m^-1·s^-1，水汽通量散度场表现为整个区域的辐合加强。（4）旱年青海高原空中水汽收支呈“盈余”状态，但比平均状况少2923．3kg·s^-1，减幅为21．88%；涝年空中净水汽通量也呈“盈余”状态，但比平均状况多7253．6kg·s^-1，增幅达53．99％。

The analysis of summer precipitation anomaly and the feature of water vapor transport in Qinghai Plateau for the last 43 years is made. It shows that （1） The summer precipitation increased at first and then decreased. After the end of 1980＇s, precipitation has a steady cycle of three-year, and is in a rainy period now. （2） The content of water vapor flux in Qinghai plateau varies from 50 to 150kg · m^-1 · s^-1, and it increases from west to east boundary. The net vapor flux has an increasing tendency in the last 43 years. （3） In a dry year, water vapor flux decreases about 10-40kg · m^-1 · s^- 1, and there is a increasing vapor flux divergence field. In a moist year, the water vapor flux increases about 10-20kg · m^-1 · s^-1 , and there is a increasing vapor flux convergence. （4） In a dry year, the net water vapor flux is positive always, but the content is low about 21.88% than average state, and it is high about 53.99% in a moist year.