地形对中期天气过程的动力和热力作用的初步探讨

A PRELIMINARY INVESTIGATION OF THE DYNAMIC AND THERMODYNAMIC IMPACT OF THE TOPOGRAPHY ON THE MEDIUM RANGE WEATHER PROCESSES

本文利用一个中期天气预报谱模式,以1979年1月23日典型的中国寒潮天气和6月14日梅雨天气为例,通过在有、无地形和热力作用下的预报高度场与实况的倾向相关系数检验和500hPa高度场及海平面气压场的变化分析,讨论了地形对中期天气过程的动力和热力作用。我们发现地形的纯动力作用对冬季中期天气过程的影响十分明显,但在夏季其影响较弱。而热力作用对冬、夏季大气的影响都具有十分重要的意义。

This paper uses a spectral model for medium range weather forecast. It is discussed that the dynamic and thermodynamic impact of the topography acts on the medium range weather processes. In the discussion, two typical cases of the summer mei-yu weather and the winter cold-wave weather in China are used. The tendency correlation coefficient of predicted height field with observed one is tested. The variation of 500 hPa height field and sea-level pressure field is analysed. It is found that the pure dynamic impact of the topography on the winter medium range weather processes is very clear. But for the summer case, this impact is weaker. It is also found that the thermodynamic impact is significant on both the winter and summer cases.