SWCWARMS模式对四川盆地强降水预报的检验分析

The Validation of Heavy Rain Forecast over the Sichuan Basin by SWCWARMS Model

利用SWCWARMS模式产品、常规观测等资料,对2017年7月27~28日和2018年7月26~27日四川盆地两次强降水过程中的环境场、降水量和物理量场等进行了12h、24h预报时效的天气学检验分析。得出SWCWARMS模式产品在强降水预报中的3大优势:(1)SWCWARMS模式对两次强降水过程的降水强度、范围等预报效果较好,尤其是降水强度更为突出,参考价值高。(2)SWCWARMS模式对中高纬大尺度环流背景和强降水主要影响系统预报效果较好,对高原低值系统也有较好的描述。(3)SWCWARMS模式对物理量场中水汽条件(比湿场)和不稳定能量CAPE值预报效果较好。同时,还需要注意的有2方面:500hPa风速和高原上空天气系统存在系统性偏弱现象;对低层风速预报偏弱,加之风向预报偏差,直接影响了强降水分布及大暴雨中心位置的正确预报。

In this study, the model ability in predicting two heavy rain events over Sichuan basin on 27 July 2017 and 26 July 2018 were verifies with the products of SWCWARMS Model, the performance of SWCWARMS Model for 12hr, 24hr numerical forecasting and conventional observation data. Three advantages of SWCWARMS model products in heavy rainfall forecast are obtained. SWCWARMS model has a good prediction effect on the precipitation intensity and range of two heavy precipitation processes, especially the precipitation intensity is more prominent. The model has a good performance for evolvement and major adjustment of circulation pattern in Asia middle and high latitude area, therefore, they can forecast the severe disaster weathers ahead. In addition, SWCWARMS model has a good prediction effect on specific humidity and unstable energy CAPE. At the same time, need to pay attention to two aspects. On the one hand, the weather system over the plateau are systematically weak, on the another hand, low-level wind speed forecast is weak and the deviation of wind direction forecast directly leads to the forecast deviation of heavy precipitation.