低频图在贵州汛期延伸期强降水预测中的应用

Application of Low-Frequency Synoptic Map in Forecasting Heavy Rainfall in Guizhou Province

本文基于低频图方法对贵州省2011—2015年59次区域性强降水过程对应的500hPa低频流场进行EOF统计分析,建立贵州省强降水过程的统计预测模型,通过外推试验开展贵州2016年汛期延伸期强降水过程预测,利用回算试验的预测准确率评估该方法的本地适用性。结果表明:影响贵州强降水的6个低频关键区分别为贝加尔湖以西地区(40°~70°N,80°~110°E,1区)、贝加尔湖以东地区(40°~70°N,110°~150°E,2区)、中国西南地区东部至华中地区(25°~40°N,100°~120°E,3区)、西太平洋地区(10°~40°N,120°~140°E,4区)、孟加拉湾地区(0°~25°N,70°~100°E,5区)和中国南海地区(0°~25°N,100°~120°E,6区)。当1、4区出现低频反气旋,3、5区出现低频气旋,2、6区有配合其它关键区的低频系统活动的环流配置为贵州省强降水过程预测模型。2016年汛期强降水过程进行预测试验的预测准确率为39.2%,表明低频图方法在贵州省强降水过程预测中的应用效果较好。

Applying the low-frequency synoptic map,the statistical prediction model of heavy rainfall in Guizhou Province is established based on the EOF analysis and statistical analysis of 500 hPa low frequency flow field corresponding to 59 regional precipitation processes from 2011 to 2015.The local applicability of the method is assessed by means of the accuracy rate of the 2016 forecast results applying extrapolation.The results indicate that the six key regions of the low frequency systems for Guizhou heavy rainfall are：west of Lake Baikal（Region 1,40°to 70°N,80°to 110°E）,east of Lake Baikal（Region 2,40°to 70°N,110°to 150°E）,east of Southwest China to central China（Region 3,25°to 40°N,100°to 120°E）,western Pacific（Region 4,10°to 40°N,120°to 140°E）,Bay of Bengal（Region 5,0°to 25°N,70°to 100°E）,southern of China（Region 6,0°to 25°N,100°to 120°E）.The prediction model of the heavy rainfall in Guizhou is：the low frequency anti-cyclone appeared in the Region 1 and the low frequency cyclone in Regions 3 and 5 and the low frequency system activity in Regions 2 and 6.According to the cycle of the low frequency system in each key area,the forecasting experiment was carried out in 2016 flood season.The prediction accuracy was 39.2%,which indicates that the application of low frequency map method is well in predicting the heavy rainfall process in Guizhou.