我国华北地区汛期降水变化趋势的初步预测

Primary Forecast for Precipitation Trend in Rainy Season in North China

根据华北地区 18个代表站 195 1- 1999年月降水资料 ,利用回归分析法研究了华北地区汛期降水的长期变化特征 ,并从海洋对气候的影响角度出发 ,运用基于均生函数的主成分建模方案对华北地区汛期降水的长期变化趋势进行了初步预测。结果表明 :华北地区汛期降水的长期变化具有明显的地域性 ;在 195 1- 1999年的 49a间 ,华北I区汛期降水量减少了近 6 4mm ,而华北II区则减少了 119mm ;华北I区汛期降水从偏多 (少 )到偏少 (多 )的转换期约为 17a,而华北II区约为 2 0a。预测结果指出 :在 1999- 2 0 0 8年的 10a间 ,华北地区汛期降水基本处于其多年平均状态 。

Based on the monthly rainfall data of 18 stations in North China from 1951 to 1999, the long term variation of the precipitation in the rainy season in North China are simply analyzed by using regress analysis method. On the view of the influence of the ocean on the climate, the primary forecast for long term trends of the precipitation in the region are carried out by using the empirical orthogonal function (EOF) model based mean generating function. The results show that the rainfall reduced by nearly 64 mm in Region I and 119 mm in Region II during 49 years (from 1951 to 1999). The transition period from the more (or less) rainfall to the less (or more) is about 17 years in Region I and 20 years in Region II. The preliminary forecast results show that during the next 10 years (1999-2008), summer rainfall in North China is basically in its multi year mean state, that is, no obvious drought phenomena.