东北平原西部沙地近10年的沙质荒漠化

Sandy Desertification in West of Northeast China Plain in the Past 10 Years

东北平原西部沙地位于欧亚大陆中纬度巨型沙带的东部边缘 ,为我国沙质荒漠化土地的东缘 ,是我国自然环境最好的沙区。随着经济的发展 ,生态环境遭到严重破坏 ,沙质荒漠化景观日益明显 ,尤其是南部的科尔沁沙地 ,沙质荒漠化已十分严重 ,已经超过与其相邻的西部环境条件更差的沙区。利用 RS和 GIS,根据 NOAA/ AVHRR数据建立的沙质荒漠化监测指标 ,对东北平原西部沙地沙质荒漠化现代过程进行了动态监测 ,在此基础上利用 TM数据对沙质荒漠化的发展方式与成因进行了深入的探讨 。

Sandy land of the Northeast China Plain lies in the eastern fringe of huge sandy belt of mid latitude in Eurasia. Using RS and GIS, the index of desertification degree is established to detect the dynamic change of desertification based on NOAA/AVHRR data, and the modern modes of desertification are studied based on TM data According to the statistics, the light desertified land decreased from 38 216 3 km 2 in 1990 to 26 452 2 km 2 in 1997, and severe and very severe desertified land increased from 3 268 2 km 2 and 3 511 9 km 2 in 1990 to 4 887 3 km 2 and 5 966 4 km 2 in 1997 respectively. The ratio of reversion desertified land, the ratio of development and the ratio of steadiness accounted for 7 7%, 39 9% and 53 4% respectively The modes of desertification include the moving accroachment of the quicksand to the farmland or grassland, sheet like enlargement of quicksand in grassland and farmland, patch like enlargement of quicksands on sand ridges around residential areas, wind erosion in farmland and grassland and sand covering on the ground Sandy lands for combating desertification can be divided into sub regions including where people removing out to abate the pressure of population, adjusting the distribution of residential areas, restricting the overgrazing, restricting the cultivation and developing fine agriculture