Based on the daily precipitation data from the meteorological stations in Sichuan and the monthly average ERA-Interim reanalysis data from 1979 to 2016, the variation characteristics of summer water vapor budget in the Sichuan Basin and its relationship with precipitation are discussed in this study. The results show that, in summer, the water vapor in the Sichuan Basin and its four sub-basins flows in from the southern and western boundaries and flows out through the eastern and northern boundaries, and the basin is obviously a water vapor sink. From 1979 to 2016, the water vapor inflow from the southern and western boundaries significantly decreased, as well as the water vapor outflow through the eastern boundary. The summer precipitation in the Sichuan Basin is significantly positively correlated with the water vapor inflow at the southern boundary and net water vapor budget of the basin in the same period, and it is negatively correlated with the water vapor outflow at the northern boundary. The southern and northern boundaries are the two most important boundaries for the summer precipitation in the Sichuan Basin. Additionally, this study reveals that, under the multi-scale topography on the east side of the Tibet Plateau, the spatio-temporal distribution of precipitation in the Sichuan Basin results from the interactions between the unique topography of the Sichuan Basin and the different modes of water-vapor transport from low latitudes. The atmospheric circulation over the key area of air–sea interaction in the tropical region and its accompanying systems, as well as the anomalies of regional circulations and water vapor transport over the eastern China and Sichuan Basin, are the main reasons for the variation in summer precipitation in the Sichuan Basin.

中文翻译：

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四川盆地夏季水汽收支变化特征及其与降水的关系

基于四川省气象台站日降水资料和1979-2016年月均ERA-Interim再分析资料，探讨了四川盆地夏季水汽收支变化特征及其与降水的关系。结果表明，夏季，四川盆地及其四个子盆地的水汽由南、西边界流入，经东、北边界流出，盆地为明显的水汽汇。1979年至2016年，南、西界水汽流入量明显减少，东界水汽流出量明显减少。四川盆地夏季降水与同期流域南界水汽流入量和净水汽收支显着正相关，与北界水汽流出量呈显着负相关。南界和北界是四川盆地夏季降水最重要的两条界线。此外，本研究还揭示，在青藏高原东侧多尺度地形下，四川盆地降水的时空分布是四川盆地独特的地形与不同模式相互作用的结果。来自低纬度的水汽输送。