东亚季风的时间变化及其预报探讨

利用全球降水气候学计划(Global Precipitation Climato1ogyt rlBpercdi tion.NCEP-2).结合东和美国环境预报中心再分析资料(National Centers for Environmental PTedic1on, 水-和年后亦亚季风指数、多变量经验正交函数展开分析(MV-EOF)等方法探讨了东亚季F风的李卫父化个手你记化。结果表明:东亚季风存在明显年周期变化,夏季风盛行于5-9月,在8月达到最大值,冬季风则在1月最强;东亚夏季风指数的年际变化与东亚地区夏季降雨有着密切关系。最后运用基于MV-EOF分析方法的Markov统计预报模型预报了1998年夏季降水异常,其结果与观测值较符,说明其具有较好的实用价值。

Discussion on the temporal variation and forecast of the East Asian monsoon

East Asian monsoon is an important component of the Asian monsoon system.To understand itscharacteristics is crucial for improving the forecast of rain and drought in China and other Asian areas.Basedon the monthly precipitation data from the Global Precipitation Climatology Project(GPCP) and reanalysis data from the National Centers for Environmental Prediction (NCEP-2),seasonal and interannual varia1onsof the East Asian monsoon were discussed with the East Asian Monsoon Index (EAMI) and Multivariable Empirical Orthogonal Function analysis method(MV-EOF). The result shows that East Asian monsoon hasan evident annual cycle,that is,the summer monsoon prevails from May to September with its peak inAugust,while the winter monsoon reaches the maximum in January. The interannual variation of East Asian Summer Monsoon Index(EASMI)is closely related to the precipitation of the East ASian area.A staiSUcalforecast based on Markov Model to forecast the East Asian Monsoon was made and it successfully forecasted the precipitation anomaly in the summer of 1998 three months ahead of time.