A STUDY OF THE VARIATION AND TENDENCY OF SURFACE DRY-AND-WET STATE OF NORTHEAST AREA IN CHINA

Based on the 80 observation station's data of monthly precipitation and mean monthly temperature over the northeast area in China from 1961 to 2000, the maximum potential evaporation, the aridity index and the water budget in the surface are computed. The spatial and temporal distribution and the variation and tendency of the surface dry-and-wet status over the northeast China are analyzed, and the relationship between the dry-wet status and precipitation and temperature is examined. The results show that not only the surface aridity index have a large interannual and decadal variation, but also have an obvious phasic change and low frequency variation characteristics. Since the mid of the 1990s, the northeast area in China shows the arid tendency obviously, and it is mainly controlled by the higher temperature which caused the potential evaporation increasing greatly.