Abstract:

In this paper,Landsat MSS/TM/ETM+ images taken on 46 different dates were used to pick up the emersed grassland of Poyang Lake in 1983~2009.We suggested the emersed grassland which appeared in one date was the grassland,got the potential grassland map，and analyzed the distribution of the emersed grassland.The correlation between the emersed grassland and the water level indicated the distribution range was significantly affected by water level:high water level,the majority of grassland flooded;low water level,the majority of grassland exposed.Furthermore,it also was affected by meteorological factors,the water level change process and etc.The area of the emersed grassland had obvious seasonal change:in spring and summer when the vegetation grows,the area dropped off,but in autumn and winter,the area increased.The maximum area was in January,the minimum was in July.The total area of potential grassland reached 2 441 km2,mainly distributed in the west bank,accounted 695% of the whole lake.The distribution feature of the increasing in the emersed grassland area was from the lakeshore to the middle with the flood to the low water