场相似在汛期暴雨预报中的应用

采用相似原理，利用车贝雪夫多项式对暴雨发生前期高空三层的高度场展开，突出与历史暴雨过程场相似特点。在高度场相似的基础上，又对和暴雨关系密切的Ｑ矢量散度，水汽通量及其散度，潜在不稳定度等物理量进行诊断分析，也取场的主要分布特点来进一步逼近，进行最佳相似预报和相似分析预报。通过试报和业务使用，效果较好。

The Application of Field similarity to Rainstorm Forecast in Flood Season

Using similarity principle and Chebashev Polynomial, the altitude field for three layers at high altitude in the earlier stage of rainstorm was expanded and the field similarity characteristics of altitude field came into prominence.The Q vector divergence, water vapour flux and flux divergence, potential unstability and other physical quantities closely related to rainstorm were analysed. Also, by futher approximating the main characteristics in field distribution, the optimum analogue forecast and analogue analasis forcast were given.