Abstract:

Under the background of climate change in the world,arid and humid conditions play an important role in keeping desertification area ecosystem stable.Based on the data of nearly 15 years of Geostationary Meteorological Satellite and the ground meteorological data,using the China Energy Water Balance Monitoring System (CEWBMS),this study obtains the changes of arid and humid conditions and vegetation growth situation in 15 desertification zones.Since 2002,the average soil moisture index (SMI) showed a trend of increase in desertification regions,and vegetation growth environment is good.Among them,in 2002—2006 and 2012—2016,the SMI is higher than average at 0.7% and 2% respectively,which illustrates the two periods of partial wetting,and positive to desertification;During the period from 2007 to 2011,the SMI is lower than average at 2.6%,partial dryness during this period,aggravating the desertification.The zones which have a positive vegetation growth environment are northern Xinjiang,southern Xinjiang,Hexi area,Qaidam basin,Hetao area,Mu Us sand land and three river source area,and the zones of negative environment are the mountains behind the Urat in Inner Mongolia,Uzhumchin and Khorchin sand land.

Key words: Soil Moisture Index (SMI), desertification regions, arid and humid conditions, trends