首页 | 本学科首页   官方微博 | 高级检索  
     检索      

华北夏季降水减少与北半球大气环流异常的关系
引用本文:郝立生,闵锦忠,顾光芹.华北夏季降水减少与北半球大气环流异常的关系[J].南京气象学院学报,2010,33(4):420-426.
作者姓名:郝立生  闵锦忠  顾光芹
作者单位:1. 南京信息工程大学,江苏,南京,210044;河北省气候中心,河北,石家庄,050021;河北省气象与生态环境实验室,河北,石家庄,050021
2. 南京信息工程大学,江苏,南京,210044
3. 河北省气候中心,河北,石家庄,050021;河北省气象与生态环境实验室,河北,石家庄,050021
基金项目:河北省重大基础研究项目 
摘    要:利用华北地区20站夏季降水资料和NCEP/NCAR再分析资料,采用趋势分析、合成分析等方法,对华北夏季降水减少与北半球大气环流异常进行对比分析。结果表明,华北夏季降水量1951—2008年呈显著减少趋势,平均每10 a减少13.4 mm,1965年发生了气候突变,之后降水量减少更加明显。北半球大气环流在1965年前后有明显不同:1)1951—1965年夏季500 hPa高度场欧洲大槽、贝加尔湖槽较深,乌拉尔山高压脊较强,经向环流表现突出;而1966—2008年夏季欧洲大槽、贝加尔湖槽较浅,乌拉尔山高压脊较弱,纬向环流表现突出。2)1951—1965年夏季500 hPa蒙古冷槽位置偏北偏西,冷空气活动经常影响华北地区;而1966—2008年夏季蒙古冷槽位置东移南压到河套附近,冷空气经常影响华北以南以东地区。3)1951—1965年夏季海平面气压场蒙古低压异常强大,而1966—2008年蒙古低压明显减弱。4)1951—1965年夏季850 hPa东亚夏季风一直伸展到华北、东北地区,蒙古地区存在明显的气旋性环流,在河套附近产生风向辐合;而1966—2008年东亚夏季风在到达30°N附近风速显著减小,很少越过长江到达华北地区,在长江流域形成了风速辐合,同时蒙古地区的气旋性环流消失,河套附近的风向辐合变的很弱。1951—1965年华北多雨是由于东亚夏季风水汽的有效输送和河套附近的风向辐合造成的,而1966—2008年长江流域多雨是由于东亚夏季风在这里产生了风速辐合造成的。华北夏季降水减少与北半球大气环流异常有很好的联系。

关 键 词:华北  夏季降水  减少  大气环流  异常

Relationship between Summer Precipitation Reduction in North China and Atmospheric Circulation Anomalies in Northern Hemisphere
HAO Li-sheng,MIN Jin-zhong,GU Guang-qin.Relationship between Summer Precipitation Reduction in North China and Atmospheric Circulation Anomalies in Northern Hemisphere[J].Journal of Nanjing Institute of Meteorology,2010,33(4):420-426.
Authors:HAO Li-sheng  MIN Jin-zhong  GU Guang-qin
Institution:1.Nanjing University of Information Science & Technology,Nanjing 210044,China;2.Hebei Climate Center,Shijiazhuang 050021,China;3.Hebei Meteorological and Ecological Environment Laboratory,Shijiazhuang 050021,China)
Abstract:Based on NCEP/NCAR reanalysis data and summer rainfall data from the 20 stations in North China,by using trend analysis and composite analysis methods,the relationship between the summer rainfall reduction in North China and northern hemisphere's circulation anomalies was investigated.The results show that summer rainfall in North China presents a significant decreasing tendency from 1951 to 2008 with an average reduction of 13.4 mm in every 10 years.This trend has been even more significant since 1965.There are obvious differences in northern hemisphere atmospheric circulation before and after 1965.Firstly,at 500 hPa height field in the summer during the period of 1951—1965,there were a shallower polar vortex and deeper trough over the European and Lake Baikal and a strong high-pressure ridge over the Ural mountain,which formed a "-+-" Eurasian teleconnection pattern resulting in outstanding meridional circulation;however,in 1966—2008,there were a deeper polar vortex and shallower trough over Europe and Lake Baikal and a weaker high-pressure ridge over the Ural mountain,which formed a "+-+" Eurasian teleconnection pattern resulting in outstanding zonal circulation.Secondly,at 500 hPa temperature field in the summer during the period of 1951—1965,the Mongolian cold trough located northerly and westerly with cold air often affecting North China region while in 1966—2008,the Mongolian cold trough location moved southeastward to the Yellow River Loop area with cold air often affecting eastern and southern regions of North China.Thirdly,at sea level pressure field in the summer during the period of 1951—1965,Mongolia low pressure was unusually large and strong but obviously weakened in the summer of 1966—2008.Fourthly,at 850 hPa wind field in the summer of 1951—1965,the East Asian summer monsoon extended to Northeast China.Meanwhile,there was an obvious cyclonic circulation in Mongolia area,which resulted in a wind direction convergence near the Yellow River Loop;in the summer of 1966—2008,the East Asian summer monsoon in the subtropical areas significantly weakened and rarely went over the Yangtze River to arrive in North China.It produced a convergence of wind speed in the Yangtze River Basin.At the same time,Mongolia cyclonic circulation disappeared and the convergence of the wind direction near the Yellow River Loop area became very weak.The rainy season in North China in the summer of 1951—1965 was a result of the effective water vapor transmission through East Asian summer monsoon and the wind direction convergence near the Yellow River Loop area.The rainy season in the Yangtze River Basin in the summer of 1966—2008 was caused by the wind speed convergence of the East Asian summer monsoon.There is a significantly obvious relationship between the summer precipitation reduction in North China and the circulation anomalies in northern hemisphere.
Keywords:North China  summer precipitation  reduction  atmospheric circulation  anomaly
本文献已被 维普 万方数据 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号