RESEARCH ON DYNAMIC CHANGE OF GRASSLAND IN WEST JILIN PROVINCE BASED ON 3S TECHNOLOGY

摘要

Grassland had been interpreted with the method that combined supervised and non-supervised classifications using Landsat data in autumns 1986, 1996 and 2000. The amelioration of algorithm promoted the accuracy. With the support of RS and GIS, spatial information of grassland landscape in west Jilin province from 1986 to 2000 was extracted, spatio-temporal dynamics of grassland and change of grassland landscape patterns were analyzed. The results show: 1) The grassland environment in the west Jilin is exacerbating and the area of grassland is decreasing by an average of 4.5×10~4 hectares a year, moreover, the grassland degeneration is severe and the area of degeneration is 81.1% of the total. 2) The degeneration of the grassland is heavier and the proportions of moderate and heavy degenerated grassland are heightening obviously, so their evaluative trends are remarkable. 3) The degenerated grassland is mainly converted into cropland and saline-alkalized land, converted area reaches 992351.4hm~2 and 563031.1hm~2. 4) The total dynamic degree of grassland is a minus value. During 1986-1996, high coverage grassland has a strong effect on change of whole grassland. The fastest degraded area is low coverage grassland from 1996 to 2000.