青藏高原大地形对冷涌作用的数值模拟研究

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

中文摘要:

      本文利用一个有限区域P-σ5层原始方程模式,用欧州中心5°×5°网格资料较好地模拟出1982年12月下旬一次冷涌的大尺度过程.结果表明:青藏高原大地形的热力作用对东亚冬季风无明显影响,而青藏高原大地形对东亚冬季风的动力作用非常显著,它强迫冷空气绕高原东侧南下,激发出冷锋后的开尔文波从而产生东北大风区.另外,冷锋南下时在其前部还产生出一种与大地形无关的重力波,它可能是冷锋本身的激发而形成的.冷涌在Hadley环流之下向南传播,在加强Hadley环流的同时使它南移.

英文摘要:

      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.