珠江上游喀斯特地区土地石漠化现状遥感分析

Analysis on Karst rocky desertification in upper reaches of Pearl River based on remote sensing

以2002年前后的Landsat7 ETM+遥感影像为主要数据源,采用人机交互解译的方法,对珠江上游喀斯特地区土地石漠化强度现状进行遥感解译,解译精度高达87%。对遥感解译分析和研究的结果表明:整个珠江上游的土地石漠化已十分严重,石漠化、半石漠化土地面积3万9900 km2,占总面积的16.4%;石漠化、半石漠化比率大于15%的石漠化县有52个,其中贵州省土地石漠化最严重,石漠化、半石漠化比率高达21.9%,有23个石漠化县(区),广西和云南相对较轻,石漠化、半石漠化比率分别为14.7%和14.4%,分别有21和8个石漠化县。珠江上游19个市(州)中就有12个市(州)的石漠化、半石漠化面积超过1000 km2,集中分布于贵州黔南州—广西河池市、贵州黔西南州—云南曲靖市和云南文山州—广西百色市3个石漠化条带上。

The status of Karst rocky desertification in upper reaches of Pearl River was analyzed based on Landsat7 ETM ＋ satellite images of 2002 in this paper, and accuracy of remote sensing classification of rocky desertification intensity was above 87 %. Analyses of remote sensing classification of rocky desertification show that the status of Karst rocky desertification intensity in upper reaches of Pearl River is very serious, and the land area of rocky desertification is about 39 900 km^2, accounts for 16.4% of total land area, and the number of counties whose rocky desertification ratio bigger than 15% is 52, which accounts for nearly 50% of all counties in the upper reaches. Among three provinces in upper reaches of Pearl River, the intensity status of Karst rocky desertification of Guizhou province is highest, whose rocky desertification ratio is about 21.9% and the number of rocky desertification counties in Guizhou is 23, while the intensity status of Guangxi and Yunnan are lighter than that of Guizhou, whose rocky desertification ratio are 14.7% and 14.4% respective- ly, and the numbers of rocky desertification counties are 21 and 8 respectively. Among the 19 cities, there are 12 cities whose land area of rocky desertification is bigger than 1 000 km^2, and they are located mainly along three belts-one from Qiannan in Guizhou to Hechi in Guangxi, another from Qianxinan in Guizhou to Qujing in Yunnan, the last from Wenshan in Yunnan to Baise in Guangxi.