Interannual variations of the Gobi Desert area from 1982-1999

摘要

There continues to be controversies among scientists whether humans are contributing to land degradation (desertification) in arid and semi-arid regions of the world. One area of considerable interest is the Gobi desert of central Asia, which is one of the largest deserts on Earth. The Gobi Desert is of particular value for addressing this question because it is divided by two countries that employ vastly different land management practices. Land use in China is high intensity and in Mongolia land use is of low intensity. In this study, climate and satellite remotely sensed data from 1982-1999 were used to investigate interannual variations in the areal extent the Gobi Desert boundary. Our results show substantial year-to-year variations in the size of the Gobi desert which was strongly correlated with annual precipitation (R~2 = 0.81, P<0.000). Based on results of logistical analysis of the climatic and remotely sensed data, an actual evapotransporation threshold of 180 mm per year was identified as the factor for discriminating between areas of desert and steppes within the study area. Correlation values between the areal extend of the desert and climate data were highly significant for study areas in both Mongolia and Inner Mongolia, suggesting that at the scale of our study, human activities contributed little to interannual desert boundary fluctuation. Due to data availability constraints, we were only able to examine satellite imagery over an 18-year period which did not include both a wet and dry cycle for this region. Therefore, a more complete understanding of Gobi Desert boundary response to interannual climatic variation will require studies extended over a longer time period.