关键词: 沙质草地, 植被覆盖, 模拟, 风沙运动, 水分补给

Abstract: A mechanism model is set up based on the characteristics of vegetation cover change on sandy grassland in arid region. The study on the sandy grassland in the lower reaches of the Manas River in Xinjiang Autonomous Region was made by using this model. The simulation included changes of soil water supply and vegetation cover in the term from July, 1999 to July, 2000. The results are verified by NOAA/AVHRR satellite data and GIS technology. The average vegetation coverage of the study area varies from 10% to 35%. The lowest value appears in April with the value lower than 10%, and the highest value appears in July with an average above 30%. Areas with high vegetation coverage are mostly distributed in south and east part of the study area as well as the low edge of the desert. The most of the study area, with a portion of 63.73 percent, has the vegetation coverage value between 10%~30%, and other classes of vegetation coverage value have a portion of around one tenth of the study area. Compared with the remote sensing data, the model is proved to be practical. The simulation results can reflect the real change of vegetation coverage.

Key words: sandy grassland, vegetation coverage, simulation, wind-sand movement, water replenishment