关键词: 江淮流域, 可利用降水量, EOF, 变化趋势

Abstract:

Based on the monthly mean temperature and precipitation grid data with 0.5°×0.5° spatial resolution over the Yangtze-Huaihe river basin in spring during 1961-2013 from the National Meteorological Information Center, the variation characteristics of spring utilizable precipitation over the Yangtze-Huaihe river basin were analyzed by using the statistical methods including the trend analysis and EOF, etc. The results showed that the precipitation, evaporation, utilizable precipitation and the proportion of utilizable precipitation to total precipitation in spring gradually decreased from the south to the north of the Yangtze-Huaihe river basin, and the spatial difference of utilizable precipitation was more obvious than precipitation and evaporation. Spatially, the precipitation and utilizable precipitation in spring during 1961-2013 showed a consistent decreasing tendency over the whole basin, while the evaporation showed a declining tendency in the north and increasing tendency in the south. The spring precipitation, evaporation and utilizable precipitation mainly presented same anomaly in whole area and opposite anomalies in the south and the north of Yangtze-Huaihe river basin, and the spatial distribution of utilizable precipitation was mainly affected by the abnormal distribution of precipitation. Further analysis showed that the increase of evaporation was more significant in more precipitation areas of Yangtze-Huaihe river basin with the rising of temperature.

Key words: Yangtze-Huaihe river basin, utilizable precipitation, EOF, variation trend