摘要
利用NCAR/NCEP再分析资料和中国气象局整编的中国 1 60站气温、降水月平均资料 ,计算并分析了 1 951年 1月— 2 0 0 0年 1 0月中国华北地区Palmerdroughtseverityindex(PDSI)。研究表明 :近 50年来华北干旱有显著的年际和年代际变化。从 2 0世纪 80年代以来 ,华北出现了持续性严重干旱现象 ;另外 ,华北地区干旱持续时间一般都在两年以上。华北夏季典型干旱年的前期 (冬季和春季 )及同期环流特征是 :北半球中高纬度 50 0hPa高度距平场出现EU型遥相关分布 ,华北地区长期处于大陆暖高压控制下。
The persistent droughts during the last two decades in North China are studied. The main results are as follows: (1) The Palmer Drought Severity Index (PDSI) shows that there is inter annual variation in droughts in North China. The inter decadal variation is even more remarkable. Before the mid 1970s, there was wet summer climate, while since 1970, there were more drought years in North China. Moreover, the most severe droughts happened after the 1980s. (2) Summer droughts in North China are the consequence of persistent anomalous circulation over the Eurasia. The main features of the anomalous circulation include that there is height anomaly in the region of 55°to 65°N , 60°to 135°E and that there was EU teleconnection and it is the main type of atmospheric circulation anomalies that causes the persistent summer droughts in North China. (3) During the summer drought years, there is continuity in the distribution of the 500 hPa height anomaly field from winter to summer. (4) The anomalies of the general atmospheric circulation during droughts in North China are not local phenomena, but the responses to the Northern Hemisphere general atmospheric circulation anomaly.
出处
《应用气象学报》
CSCD
北大核心
2003年第2期140-151,共12页
Journal of Applied Meteorological Science
基金
中国科学院资源环境领域知识创新工程重要方向项目 (编号KZCX2 2 0 3)
"国家重点基础研究发展规划"项目 (编号G19980 4 90 0 )第一部分的资助
