东亚夏季风系统与青藏高原冬季植被的关系

Study on the relationship between summer monsoon of east Asia and winter NDVI variability in Tibetan Plateau

用1982年1月—2001年12月NDVI资料、台站日降水资料和NCEPⅠ/NCAR再分析资料,首先利用SVD方法分析了青藏高原冬季NDVI与我国降水的关系,指出青藏高原冬季NDVI与我国夏季降水相关系数从南到北呈"+-+-"相间分布,高原冬季NDVI增大(减小),随后夏季降水在华南和华北地区增加(减少),而长江流域和东北地区降水减少(增加)。然后通过合成法,分析了高原冬季NDVI大、小值年东亚夏季风系统的变化,得到在青藏高原冬季NDVI大值年时,夏季马斯克林高压偏弱,而澳大利亚高压偏强。赤道辐合带强度偏强,有利于越赤道气流的加强,使南海夏季风爆发偏早。同时南亚高压偏弱位置偏西,副热带高压位置偏东偏北。副热带西风急流的位置也偏西偏北。

By using normalized difference vegetation index（NDVI）,the daily rainfall data and the NCEP/NCAR reanalyzed data during January 1982—December 2001,the relationship between winter NDVI over T-P and summer precipitation in China is analyzed by SVD,it suggests that the distribution of correlation coefficient shows ＂＋-＋-＂ from south to north.When the winter NDVI is high（low）,the summer precipitation in the region of Yangtze River and northeast China is decreased（increased）,but the summer precipitation in Huanan and Huabei is increased（decreased）.The variation of the summer monsoon of east Asia in winter NDVI high and low years is analyzed by using composite analysis.The result indicates that when the winter NDVI of T-P is high,Mascarene high tends to be weak,but Australia high tends to be strong,and the intensity of equatorial convergence belt（ITCZ） is inclinable to being strong,it makes the cross-equatorial flow strong and the South China Sea monsoon outbreak early.At the same time,the South Asia High is weaker and its position is more westward,but the location of western Pacific subtropical high is close to east and north,and the position of subtropical westerly jet is close to west and north.