基于TM影像的川西北理塘草地沙化的时空特征

Temporal and spatial distribution of Litang rangeland's desertification on North-western plateau of Sichuan using TM image

本文基于TM影像,采用植被盖度作为草地沙化的遥感监测指标,分析了川西北理塘草地沙化的时空特征。研究结果表明:①研究区草地沙化比较严重,沙化草地面积占研究区总面积的34%;中度沙化与重度沙化占监测草地面积的12.3%与5.1%,轻度沙化占16.6%。②从空间上看,中度沙化与轻度沙化分布区域普遍,重度沙化区集中分布在东南部与西北部。从时间上看,1989年至2005年以来,沙化草地面积年增加为42.87km2,年增加率为2.1%,草地沙化不断增加的趋势明显。③采用遥感技术,通过提取植被指数转为植被盖度来监测草地沙化,是一种的简单、快捷、切实可行的方法。

Based on the TM image,using vegetation cover as the main evaluation index of the remote sense monitoring,temporal and spatial distribution of Litang rangeland＇ s desertification was analysed, The result indicated that grassland desertification was serious. The areas of rangeland＇ s desertification occupied 34 % of the total grassland area. Seriously desertificated and moderately desertificated respectively occupied 12.3 % and 5.1% of the study area, and the hghtly occupied 16.6 %. According to spatial distribution, the moderately desertificated and lightly desertificated had a very wide distribution ,and seriously distributed in the northwest and southeast of the study area. From 1989 to 2005 ,the area of rangeland＇ s desertification had an significant increase of 42.87 square kilometers with an average rate of 2.1 every year. The remote sense monitoring through abstracting vegetation index and converting it into vegetation cover was a easy, convenient and practicable method to monitor for grassland desertification.