Forecasting the Quasi-stationary Front Rainstorm in Southeast China Using the Synthetically Multilevel Analog Forecast Technology  

作　　者：Li Bo Zhao Si-Xiong Yao Zhi-Gang 

机构地区：[1]Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Atmospheric and Oceanic Science Letters》2009年第1期68-72,共5页大气和海洋科学快报(英文版)

基　　金：financially supported by the National Basic Research Program of China (Grant No. 2009CB421 401)

摘　　要：The authors use numerical model integral products in a third level forecast of synthetically multi-level analog forecast technology.This is one of the strongest points of this study,which also includes the re-ducing mean vacant-forecast rate method,which pos-sesses many advantages with regard to filtering the analog term.Moreover,the similitude degree between samples is assessed using a combination of meteorological elements,which works better than that described using a single element in earlier analog forecast studies.Based on these techniques,the authors apply the model output,air sounding,surface observation and weather map data from 1990 to 2002 to perform an analog experiment of the quasi-stationary front rainstorm.The most important re-sults are as follows:(1) The forecast successful index is 0.36,and was improved after the forecast model was re-vised.(2) The forecast precise rate (0.59) and the lost-forecast rate (0.33) are also better than those of other methods.(3) Based on the model output data,the syn-thetically multilevel analog forecast technology can pro-duce more accurate forecasts of a quasi-stationary front rainstorm.(4) Optimal analog elements reveal that trig-gering mechanisms are located in the lower troposphere while upper level systems are more important in main-taining the phase of the rainstorm.These variables should be first taken into account in operational forecasts of the quasi-stationary front rainstorm.(5) In addition,experi-ments reveal that the position of the key zone is mainly decided by the position of the system causing the heavy rainfall.The authors use numerical model integral products in a third level forecast of synthetically multilevel analog forecast technology. This is one of the strongest points of this study, which also includes the reducing mean vacant-forecast rate method, which possesses many advantages with regard to filtering the analog term. Moreover, the similitude degree between samples is assessed using a combination of meteorological elements, which works better than that described using a single element in earlier analog forecast studies. Based on these techniques, the authors apply the model output, air sounding, surface observation and weather map data from 1990 to 2002 to perform an analog experiment of the quasi-stationary front rainstorm. The most important results are as follows: (1) The forecast successful index is 0.36, and was improved after the forecast model was revised. (2) The forecast precise rate (0.59) and the lost-forecast rate (0.33) are also better than those of other methods. (3) Based on the model output data, the synthetically multilevel analog forecast technology can produce more accurate forecasts of a quasi-stationary front rainstorm. (4) Optimal analog elements reveal that triggering mechanisms are located in the lower troposphere while upper level systems are more important in maintaining the phase of the rainstorm. These variables should be first taken into account in operational forecasts of the quasi-stationary front rainstorm. (5) In addition, experiments reveal that the position of the key zone is mainly decided by the position of the system causing the heavy rainfall.

关 键 词：synthetically multilevel analog forecast technology quasi-stationary front rainstorm analog forecast experiment test of model capability forecast range 

分 类 号：P458.121.1[天文地球—大气科学及气象学]