A STUDY OF THE TIBETAN PLATEAU EFFECTS ON COLD SURGE BY USING NUMERICAL MODEL

The effects of the Tibetan Plateau orography on East Asian cold surge in Dec.1982 is studied by using the P-σ incorporated coordinate 5 layer primitive equation numerical model.The results show that tLe thermal effects of the Tibetan Plateau and the latent heat as well as the humidity have no importance on the cold surge,but it mainly depend on the dynamic effect of the topography.The dynamic effects force cold air southward around the plateau,stimulate the Kelvin wave behind cold front and cause the max.NE wind.Otherwise,there is a gravity wave before the cold front while it moves southward.The gravity wave has no relation with the topography,but may be caused by the cold front itself.Cold Sure propagates southward only under the Hadley cell.It intenseifies Hadley Cell and forces the cell to move southward simultaneously.