地形效应影响数值预报结果的试验研究

本文利用P-σ混合坐标系的有限区域嵌套细网格原始方程模式，选取Wayne台风天气形势演变过程为个例，试验讨论了地形效应对数值预报结果的影响。 试验方案分三类，一是真实地形，二是部分真实地形，三是均匀地形。文中着重比较了不同地形方案对Wayne台风天气形势演变过程的影响。结果指出，对西太平洋副热带高压进退及高空西风槽的活动，地形的影响极为显著，真实的地形有助于改善预报质量，使得形势预报结果更为接近实际。地形对温度场的影响局地性较强，模式地形过矮和过于平滑将使得地面温度的预报偏高。对降水场的预报，数值模式普遍存在的降水区域过于分散的问题，可能是由于模式地形影响的缘故。但对大范围雨带的分布来说，地形不具有决定性的因素。模式地形对降水的影响，主要表现在其增幅效应和降水区分布的结构上，即模式地形增高，降水量将适度增大，雨区结构将更为复杂。地形的影响在风场环流预报中体现得也极为明显。最后作者指出，在数值模式中引入合理的模式地形，是改善预报质量的有效途径之一。

An Experimental Study on the Effects of Topography on Numerical Prediction

Numerical prediction experiments are made by using an one-way nested fine-mesh limited area primitive equation model and a case study of Wayne Typhoon is analysed in some details about theeffeCts of topography on numerical prediction in thes paper. There are three kinds of experimentalSChemes. The first is real model topography, the second is partly real topography and the third is uniform topography. The focus of this paper is the comparisons and discussion of the effeCts of toPOgraphyon the synoptic situation of typhoon. The results show that the effects of topography on the Pacificsubtropical high pressure zone and the structure of westerly trough are very evident, and better resultScould be obtained by using more realistic topography . The variation of topography leads to the localvariation of temperature field. Topography not only contributes to the precipitation amount evidentlybut also affects the distribution of rainfall in some extent, but it is not the main factor controlling thedistribution of rainfall, at least in this case. The effeCts of topography can also be seen in the wind profile. At last, the authors point out that more realistic configuration of topography can improve the forecast quality and give more reliable results.