Interdecadal Variation of Water Vapor Transport over East Asia and Its Impacts on Rainfall over Eastern China in Summer
Interdecadal Variation of Water Vapor Transport over East Asia and Its Impacts on Rainfall over Eastern China in Summer
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发表时间：
2009
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通讯作者：
Ma Jiafu
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作者：
Ma Jiafu
本文利用时间序列分析方法，分析了东亚地区夏季水汽输送的年代际变化及其对中国东部降水的影响，利用1951 ~ 2004年NCEP/NCAR月再分析资料和中国160个测站的月降水资料，分析了中国东部地区夏季降水的分布特征，结果表明：中国东部地区夏季降水的主要分布型是南涝北涝，南涝北涝是中国东部地区夏季降水的主要分布型，南涝北涝是中国东部地区夏季降水的主要分布型。20世纪70年代中后期至90年代初的中旱，并出现了南方洪水，20世纪90年代以来，我国东部地区夏季降水的年代际变化十分显著，雨带明显南移。我国东部地区夏季降水的主导模态及其时间序列系数揭示了我国东部地区夏季降水的年代际变化特征。1974年以来，东亚大陆东部纬向水汽输送存在由强变弱的转折点和年代际减弱趋势。印度大陆、孟加拉湾北方、长江中下游、南海和热带太平洋地区自1973年以来具有由弱到强的转折点和年代际增强趋势。东亚地区夏季水汽输送的空间演变是导致东亚地区由南涝/北旱向南涝/北旱转变的关键因素之一，从而导致东亚地区雨带南移。
This paper analyzes the interdecadal variation of water vapor transport over East Asia and its impacts on rainfall over eastern China in summer by using EOF analysis method,NCEP/NCAR monthly reanalysis data and monthly rainfall data covering 160 stations over China from 1951 to 2004 in summer.The results show that the main distribution mode of summer rainfall over eastern China is south and north flooding/middle drought from the mid-and late of the 1970s to the beginning of the 1990s and presents a south flooding/north drought pattern since the beginning of the 1990s.The interdecadal variation of summer rainfall over eastern China is very significant and rain belt shifts southward obviously since the 1990s.The leading mode of EOF and its time series coefficients reveal that the meridional water vapor transport over east of East Asia Mainland is characterized by a turning point from strong to weak and a decadal weakening trend since 1974.The zonal water vapor transport over India Mainland and northern part of Bay of Bengal,middle and lower reaches of Yangtze River Valley,South China Sea and tropical Pacific region is characterized by a turning point from weak to strong and a decadal enforcing trend since 1973.The temporal-spatial evolution in summer water vapor transport over East Asia is one of key factors that trigger a shift from south and north flooding/middle drought to south flooding/north drought,which leads to the induction of the rain belt shifting southward.