我国地表水资源近期变化趋势

分析全国及 9大流域片 1997～ 2 0 0 0年逐年降水量、天然径流量的变化趋势及降水量年内变化情况 ,研究近期我国地表水资源变化趋势及近年旱涝特点 .研究表明 :自 1997年以来 ,我国降水量除 1998年比多年平均值偏多 11.6 % ,长江、嫩江等河流发生了特大洪水 ,是丰水年外 ,其余的1997,1999,2 0 0 0年 3年均比多年平均值偏少 0 .9%～ 4 % ,属平水年 ,为南丰北枯型

Trend of short-term variation of surface water resources in China

An analysis was made of the trend of variation of annual precipitation and natural runoff in China and 9 large river basins for 1997～2000 and the variation of precipitation in each year, and a study was performed on the trend of variation of surface water resources and characteristics of droughts and floods in China for resent years. The results show that, in 1998, extraordinary floods occurred in the Yangtze River and the Nenjiang River Basins, and the precipitation in 1998 was 11.6% larger than the long term annual mean value, so the year of 1998 was a high flow year, that the precipitation of other three years (1997,1999, and 2000) was 0.9%～4% smaller than the annual mean value, and those years were mean flow years, and that water resources are abundant in South China and scarce in North China.