Numerical Prediction of the Heavy Rainfall Vortex Over Eastern Asia Monsoon Region

Abstract

A series of numerical forecasts were carried out to investigate a heavy rainfall event over the monsoon region of Eastern Asia which was caused by a vortex formed over the Tibet Plateau during Summer. The ECMWF global grid point model was capable of predicting the vortex four days in advance. The importance of the moist processes in the development of the vortex was investigated by comparing the results from a moist and a dry (without latent heat) versions of the model. It was found that the low level jet associated with the vortex and the upper level easterlies are more active when the latent heat is included in the model.
The ECMWF limited area model with resolution 0.5° of latitude and longitude (-37km at 45°N) was used in order to obtain a more accurate and detailed forecast. Some intermediate scale disturbances were predicted over the Tibet Plateau and verified with satellite pictures and observations. This result is significant for the problem of numerical weather prediction over the Asian Continent.