Palmer干旱指数在华北干旱分析中的应用

Analysis of Drought in Northern China Based on the Palmer Severity Drought Index

利用中国气象局整编的1951年1月～2000年10月中国160站气温、降水月平均资料,计算了1951年1月～2000年10月我国160站修正的Palmer drought severity index(PDSI).PDSI指数对我国的干旱和洪涝过程都有很好的指示意义.华北地区干旱持续性非常强,持续时间一般都在两年以上.华北地区干旱不但年际变化大,年代际变化也显著,近50年来华北干旱主要发生在20世纪70年代以后,且干旱强度有所增加.夏季伴随干旱过程常常出现高温酷暑天气.

Drought during the period 1999-2000 in North China is studied by using monthly mean temperature and precipitation data from 160 stations covering January 1951 to October 2000. The revised Palmer drought severity index (PDSI) of the 160 stations covering the same period was also calculated. It is found that the protracted drought was a manifestation of an abnormal form of general circulation. The PDSI can characterize the temporal and spatial distributions of remarkable droughts and floods in China. During 1999-2000 there was a persistent negative PDSI in North China, the PDSI also shows that there is a marked interannual and interdecadal variation of drought in North China. From 1950-1970 there is a wet summer climate, while since 1970 there have been more drought years in North China.