摘要

Based on observational monthly precipitation and temperature datasets of 60 stations in China, the characteristics of the precipitation, evapotranspiration, potential evapotranspirtation and their relationship with regional warming have been analyzed, especially for three sub-regions in North China. The results indicate that there are significant characteristics of historical variations of surface hydrologic processes and regional differences in the and - regions of North China. And there is a stage correlationship between evapotranspiration and surface air temperature. It means there is a positive correlationship between them in one period and negative correlation in another one. The results also indicate that the regional warming in North China is a main reason for the intensifying drying trend.