1988-2009年安县山区植被覆盖度变化动态分析

利用像元二分模型对1988年、1995年、2000年、2007年和2009年5期安县山区的影像数据进行植被覆盖度估算.通过植被覆盖度变化转移矩阵总体评价21年间安县山区植被覆盖度的变化情况,并定量分析1988-1995年、1995-2000年、2000-2007年、2007-2009年四个时段的植被覆盖度变化趋势.结果表明:(1)21年间安县山区的植被覆盖改善的面积为34706 hm2,退化部分的面积为36920hm2;(2) 1988-1995年间、1995-2000年、2000-2007年及2007-2009年间安县山区整体植被覆盖度等级提高的面积为39205、51014、54316和38813hm2,退化部分的面积分别为39563、45650、55422及44271 hm2.2007-2009年此时段受汶川地震影响,地表植被结构严重破坏.利用本文的方法可达到对植被覆盖度进行反演及对该县山区生态环境的保护和可持续发展做出贡献,从而达到创建和谐社会的目的.

Dynamic analysis of the fractional vegetation coverage in the mountainous area of Anxian from 1988 to 2009

In this paper, five image data were studied for estimating the fractional vegetation coverage in the mountainous area of Anxian using dimidiate pixel model for 1988, 1995, 2000, 2007 and 2009. The fractional vegetation coverage in the mountainous area of Anxian during the 21 years was completely evaluated through analyzing the change of the transfer matrix of the vegetation coverage. The change trends of the vegetation coverage during four periods, 1988-1995, 1995-2000, 2000 -2007, and 2007-2009, were analyzed individually. The results showed: 1) The mountainous area in Anxian with an improved fractional vegetation coverage during the past 21 years was 34706 hm², while the degraded part covered an area of 36920 hm². 2) During the periods of 1988-1995, 1995 - 2000, 2000-2007, and 2007-2009, the mountainous area in Anxian with an improved fractional vegetation coverage was 39205, 51014, 54316 and 38813 hm², respectively, while the degraded part covered an area of 39563, 45650, 55422, and 44271 hm², correspondingly. During the period of 2007-2009, the vegetation structure in this region was severely damaged due to the Wenchuan earthquake. With the method used in this paper, we achieved the vegetation coverage inversion, which could protect the mountainous ecological environment and contribute to the sustainable development in the region.