Abstract:

The soil-plant-atmosphere continuum （SPAC） in arid and semi-arid regions converts water rapidly， while the conversion time of surface water and groundwater is short. The change of water body area plays an important role in indicating shallow groundwater in arid and semi-arid regions. A total of 29 periods of Landsat remote sensing images from 1990 to 2018 were processed through the Google Earth Engine platform， which obtain the variation characteristics of the subsurface water bodies in the Mu Us Sandy Land in a short-term sequence. The results show： The variation of water bodies in the Mu Us Sandy Land has strong seasonal characteristics. The two peaks occurred in April and August during the year， respectively. The monthly area increased by 44.867 km² （28.60%） and 55.477 km² （34.39%） respectively. From 1990 to 2018， the surface water body fluctuated greatly， and the total area of the water body in the study area was reduced from 379.771 km² to 275.492 km²， a total reduction of 104.278 km² （27.46%）. The change of water body area in the study area is mainly affected by precipitation， vegetation coverage and human activities. The correlation coefficient between precipitation and water body area within 29 years is 0.57， while the correlation coefficients between 1991-2008 and 2009-2017 are 0.59 and 0.77. Vegetation coverage and water body area were negatively correlated within 29 years， but the correlation was not significant. It shows that human activities in the Mu Us Sandy Land have a greater impact. In order to control the sandy land， human activities should be reduced.

Key words: Mu Us Sandy Land, water body area, vegetation coverage, water resources