我国东部冬季水汽输送年代际变化

Inter-decadal Variation of Water Vapor Transport over Eastern China in Winter

利用NCEP／NCAR提供的1948～2011年全球逐月分析资料，对月平均资料进行整层积分并通过EOF方法，研究我国东部冬季水汽输送的特征。结果表明，我国东部12、1、2月份水汽输送在纬向上均为西风方向的水汽输送，异常大值区位于太平洋一带；在经向上12、1、2月份水汽输送均为南风方向的水汽输送，异常大值区位于云南一带。第1空间模态，12、1月份在105°E以东水汽输送的方向分别为东南风、东北风方向的平流输送，2月份在120°E以东水汽输送的方向为东南风方向的平流输送；第2空间模态，12月份在110°E以东、1月份在90°E以东的水汽输送的方向均为偏南风方向的平流输送，2月份在105°E以东水汽输送的方向为西南风方向的平流输送；第3空间模态，12月份在105°E以东水汽输送的方向为西南风方向的平流输送，1月水汽输送在东南地区是西南风方向的平流输送，2月份在95°E以东水汽输送的方向为偏南风方向的平流输送。前3个模态时间序列表明我国东部水汽输送存在明显年际年代际变化。

Using global monthly data during 1948 -2011 provided by NCEP -NCAR, monthly average data was accumulated, through EOF method, characteristics of water vapor transport over eastern China in winter were studied.The results showed that water vapor transport in Dec., Jan., Feb.is always west wind , abnormal large value area is located in the Pacific Area;The meridional water vapor transport in eastern China in winter is always south wind , abnormal large value area is located in Yunnan .In the first space mode , water vapor transfer is always southeast wind and northeast wind in Dec.and Jan.respectively in east of 105°E, water vapor transfer is always southeast wind in Feb.in east of 120°E;in the second space mode, water vapor transfer in east of 110°E in Dec.and east of 90°E in Jan.is always south wind, water vapor transfer in east of 105°E in Feb.is always southwest wind;in the third space mode, water vapor transfer in east of 105°E in Dec.is southwest wind, water vapor transfer in Jan.in southeast region is southwest wind, water vapor transfer in east of 95°E in Feb.is south wind.The first 3 modal time se-ries showed that the water vapor transport over Eastern China has obvious inter -decadall and inter-annual variation.