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.