摘要
由850hPa的风场资料和海平面气压资料计算两个东亚冬季风强度指数,结合月平均降水资料,分析我国南方冬季降水对冬季风响应的空间分布型及其在冬季各月的差异。结果表明:12月东亚冬季风强度比1、2月的弱,同期的降水对其响应不明显;1月冬季风比2月强,同期降水对季风的响应比2月更强些。在1、2月,强(弱)东亚冬季风易造成南方冬季降水偏少(多),但这种响应是时间和空间的函数,随时间变化且有明显的区域特征。1月的强响应区基本上连成一片,强响应中心散布于其中;最明显的中心区在淮河以南附近,区域中心值<-0.5;响应强度由此中心向南变弱,但依然分别在湖南东北部、江西东北部以及四川东北部都出现了较强中心区,区域中心值都为-0.35左右;2月的响应区相对1月作了总体的顺时针偏转和稍微的北缩。分析发现,响应区的空间分布可以从地形和地势分布解释,响应区的时间变化与850hPa的风场有关。
Based on the 850 hPa wind field and sea level pressure （SLP） data,the East-Asian Winter Monsoon Index （EAWI） were calculated and its annual change in the past 60 years were analyzed.The relationship of EAWI and precipitation in Southern China are further studied.The results indicate that rainfall in Southern China is associated with the East Asian winter monsoon.This kind of relationship of EAWI and precipitation in Southern China is relatively notable in January and February,and weak in December.Note that the precipitation reacts in different ways in January and February,respectively： In January,high response zone appears in a single stretch within which there are response centers;the most marked responses locates to the south of Haihe River,the response strength reaches-0.5;dispite the strength weaken when it goes lower latitude,northeast of Hunan,Jiangxi,and Sichuan occur relatively weaker response centers.In February,the response zone makes a slight clockwise rotation and a withdrawal to north.The spatial pattern of response of rainfall to winter monsoon can be interpreted by topography and its temporal variation is correlated to 850 hPa wind field.
出处
《高原气象》
CSCD
北大核心
2010年第4期975-981,共7页
Plateau Meteorology
基金
国家自然科学基金重点项目"黄土高原陆面过程观测与试验研究"(40830957)资助
关键词
中国南方
冬季降水
冬季风强度
响应的时空分布
Southern China
Winter precipitation
Winter monsoon intensity
Temporal and Spatial distributions of response
