Dynamic Analysis of Vegetation Fraction Change in Wuhan Region from 1988 to 2002
武汉地区1988~2002年植被覆盖度变化动态分析

Vegetation includes all plant communities that cover the earth surface.And vegetation fraction is the most important index to scale the status of the vegetation of the region so the vegetation is the composition and the function body of ecological system.Vegetation fractions in different districts of Wuhan were calculated based on remote sensing images (TM images and ETM+ images) in 1988,1991,1996 and 2002 by employing method for dimidiate pixel model,and the vegetation fraction maps of different periods were generated to analysis the temporal change of vegetation fraction of Wuhan area.The results showed that,the vegetation fraction changed much from 1988 to 2002; the average vegetation fraction of the whole area was decreased from 58.41% to 50.45%,especially in Jiangxia district and the central district.From 1996 to 2002 is the period which vegetation fraction decreased the most sharply in this period.From 1991 to 1996 the vegetation fraction was lightly increased in the whole study area.Analyzing spatial changing characteristics in the whole study area we can see that,the whole area was in the decreasing moment,especially in Jiangxia district and the central district,this was the result of urban development,and led to the malign development of the environment,worthy of all aspects of attention.