对云南2011年冬季降水的延伸期天气预测试验

Extended range weather forecast experiment to winter precipitation over Yunnan in 2011

在前期对MJO研究基础上于2011年11月8日根据MJO的活动情况及发展趋势,作出"云南延伸期天气预测第3次试验(11月12日—12月15日)".通过对天气形势及云南省天气实况的具体对比分析,就该实验进行了认真检验:在干窗口期云南日降水距平百分率几乎维持在-100%,基本无有效降水,与试验结论 1基本一致;在湿窗口期有2次合适的环流形势引导赤道地区的水汽进入云南,分别造成云南南部及云南东部的降水和雨雪天气过程,与试验结论 2和3一致;在干窗口后期滇中以南、以东地区出现一次小雨降水过程,预报试验对MJO的传播速度估计偏慢;本次在西南地区极端干旱背景下的延伸期预测实验是成功的,为云南省气象台提高冬季延伸期干湿预报和雨雪天气预报的水平提供了实用的理论依据,对提前准备人工降雨等工作以缓解西南地区的旱情有很好的贡献.

On base of preceding research to MJO, in accordance with activities and developing trend of MJO, the Third Experiment to Extended Range Weather Forecast over Yunnan（ 12th of Nov - 15th of Dee） ＇in 8th of Nov in 2011 ;By way of contrast and analysis to real weather situation in Yunnan, this paper tests above experi- ment： In Dry Window Phase, Yunnan daily precipitation anomaly percentage was almost -100% and lack of ef- fective precipitation, which is concordant with experiment result 1 nearly;In Wet Window Phase, there was two times appropriate circulation leading tropical water vapor entering Yunnan,which caused rainy and snowy weather in south and east of Yunnan, that is concordant with experiment result 2 and 3 ; In late of Dry Window Phase, a light rainy process appeared in area of south and east to middle Yunnan, which shows the estimate to MJO propa- gation is slower in experiment resuh;This extended range forecast experiment on background of extreme dry in southwest area of China is successful, and provides practical theoretical foundation for Yunnan province weather station to advance the abilities of extended range forecast to wet/dry and rainy and snowy weather in winter,and contributes to preceding prepare artificial rainfall works to disease dry situation in southwest area in China.