中尺度风场客观分析方法的比较研究

COMPARATIVE STUDY OF OBJECTIVE ANALYSIS METHODS FOR MESOSCALE WIND FIELD

本文采用数值试验研究了直接差分法,变分法以及辐散直接调整法在中尺度风场客观分析方法应用中的优缺点。直接差分法得到的整层辐散值最小,所用机时最短,但计算区域上部的垂直速度值偏大。变分法可以克服直接差分法垂直速度值偏大的缺陷,但所用的机时多几十倍。辐散直接调整法具有上述两种方法的优点,调整后的散度场和垂直速度场较合理,机时饺变分法少几倍。

The strong and weak points of direct-difference,variational calculus and direct-adjusting di-vergence methods for mesoscale wind field have been evaluated by numerical experiments.Themajor results of experiments are as follows:(1)As shown in other experiments,the direct-differ-ence method can get a wind field of minimum integral divergence with a short computer time,butthe vertical motion obtained in the upper calculation area is overestimated.(2)The variationalcalculus method is able to overcome the above disadvantage,but the computer time needed is toomuch.(3)The direct-adjusting divergence method possesses the advantages of the former twomethods and can get a reasonable divergence wind field with a compromising computer time.