夏季风北推和强度对我国北方夏季降水影响的年代际特征  

Interdecadal Characteristics of the Influence of Northward Shift and Intensity of Summer Monsoon on Precipitation over Northern China in Summer

作　　者：吴长刚[1] 刘鸿升[1] 谢安[1] 

机构地区：[1]北京大学物理学院大气科学系,北京100871

出　　处：《高原气象》2005年第5期656-665,共10页Plateau Meteorology

基　　金：国家重点基础研究发展规划项目(G1999043405)资助

摘　　要：利用近50年NCEP/NCAR的候平均风场和比湿场资料,计算了东亚夏季风北界的位置,发现季风北界存在着明显的年代际变化,季风北界偏北的年份集中于1950年代和1960年代,而偏南的年份则集中于1980年代和1990年代,并且各个季风区的季风北界的年代际变化比较一致.利用这些资料定义了'区域夏季风指数',更好地反映东亚夏季风的强弱和北方各地区旱涝之间的关系;用合成分析方法比较了夏季风强度与北方各干旱半干旱区域旱涝变化的关系,说明华北地区最为敏感,区域季风指数与7,8月降水量的关系最好.最后用小波分析方法,讨论了这些区域的夏季风强度和夏季降水量在不同时间尺度上的关系,发现区域季风强度指数和各季风区降水量的关系在15年左右的年代际尺度上关系最好,在3～5年的年际尺度上也有比较好的相关.这些结果对于北方地区的气候趋势预测有一定参考价值.The location of northward shift of East Asian Summer Monsoon is calculated by using NCEP/NCAR air temperature and specific humidity reanalysis data in recent 50 years. It is found that there is obvious interdecadal change in the north boundary of monsoon region, and the years with the far north boundary centralize in 1950＇s and 1960＇s, with the far south, in 1980＇s and 1990＇s, the interdecadal change of north boundary of summer monsoon in each monsoon region is consistent. The regional monsoon index is defined by using these data, in order to reflect the relationship between the intensity of East Asian summer monsoon and drought/flood in Northern China and improve the low correlation between the situation of northward shift of summer monsoon and drought/flood in Northern China, and the arid and semiarid regions where is sensitive to the intensity of summer monsoon is compared by composite analysis. In the last, the relationships between the regional summer monsoon index and the precipitation on different time scales in July and August is discussed by wavelet analysis. The correlation between regional summer monsoon index and precipitation in summer is high on interdecadal scale about 15 years and on interannual scale of 3-5 years.

关 键 词：东亚夏季风 季风北界 年代际变化 区域夏季风指数 北方旱涝 小波分析 

分 类 号：P425.42[天文地球—大气科学及气象学]