青藏高原热力对四川盆地西部一次持续性暴雨影响的数值模拟

通过对四川盆地西部一次持续性暴雨过程的半理想数值模拟，研究了青藏高原热力作用对四川盆地持续性暴雨过程的影响。研究表明，高原的热力作用对于下游地区有着显著的影响，主要表现为:（1）关闭高原地面感热和潜热后，高原地区和四川盆地西部的降水明显减弱，而盆地中东部降水却有所加强，且四川盆地降水的日变化特征稍有减弱；（2）500 hPa青藏高原上的短波槽减弱，位于四川盆地中西部的背风槽强度、范围有所减弱，但低层盆地东部的气旋性涡旋加强；（3）涡度收支的定量分析发现，关闭高原热力作用后，盆地东部对流层低层垂直风切变的增强使得夜间倾斜项的正贡献增强，从而使该区域涡旋发展加强，盆地东部降水增强。

Numerical Simulation of Impacts of the Tibetan Plateau Heating on a Persistent Heavy Rainfall in Western Sichuan Basin

The influence of sensible and latent heat anomalies over the Tibetan Plateau (TP) on a persistent rainfall in western Sichuan Basin is investigated via a semi-idealized mesoscale numerical model WRF (Weather Research and Forecasting) simulation. Analyses of the simulation show that when the heating on the TP is turned off, rainfall decreases in the TP and western Sichuan Basin but increases in central and eastern Sichuan Basin, while the diurnal variation of precipitation weakens; the trough over the TP on 500 hPa disappears, the strength and scope of the westerly trough reduces slightly, but the meso-cyclone at low levels in eastern Sichuan Basin enhances; quantitative analysis of vorticity budget during the heavy rain period indicates that the intensification of vertical wind shear in the lower troposphere makes positive contribution to strengthening the TILT (tilting term) in eastern Sichuan Basin, and thus facilitates vortex development in the key area of Sichuan Basin, which also leads to increases in precipitation in eastern Sichuan Basin.