Study on dynamic changes of land desertification in the circum-lake zone of the Qinghai Lake in the past 30 years supported by Remote Sensing and Geographical Information System

The circum-lake zone of the Qinghai Lake is one of the most serious regions of desertification on the Qinghai-Tibetan Plateau. Based on Remote Sensing (RS) and Geographical Information System (GIS) techniques, the four sets of remote sensing images acquired in 1976, 1987, 1995, and 2006 were selected to conduct thematic information extraction in 14,300 km² of land in the circum-lake zone using the Earth Resource Data Analysis System (ERDAS) image and information processing function. In the meantime the off-site interpretation and filed check-correction methods were used to reconstruct the temporal-spatial dynamic changes and differentiation patterns of land desertification in the circum-lake zone in the past 30 years, and based on this, the developmental trend of land desertification in the next 20 years was predicted. The results of the study show that in the past 30 years land desertification in the region experienced a continuous fluctuation between rapid- and slow-development processes in time, while in space it exhibited a few small patchy distributions or sporadic distributions in many places while at the same time, four large sand-dominated distributions stood out and evolved into a circum-lake belt differentiation pattern with a lakeside dike as the connecting line. Due to the integrated effects of climate changes, human activities and artificial rehabilitation, land desertification area in the region in the next 20 years will exhibit an increasing trend in the first 15 years and then increase at a slower rate, and afterward occur in a reverse, decreasing trend.