鄂尔多斯高原西部土地荒漠化动态分析——以鄂托克旗为例

DYNAMIC ANALYSIS OF DESERTIFICATION IN THE WESTEM OF ORDOS PLATEAU-The case of etoke banner

荒漠化作为1个全球性的重大环境问题,引起了世界各国的高度重视。本文以研究区1989年、2000年和2005年的TM影像作为基本数据源,在野外实地考察建立荒漠化遥感解译标志的基础上,通过人机交互判读提取土地荒漠化信息,建立土地荒漠化空间数据库。结果表明,研究期内研究区荒漠化形势十分严峻并呈逐渐恶化态势,平均荒漠化率近80%,风蚀荒漠化、水蚀荒漠化和盐渍化面积比大致为65:10:5。风蚀荒漠化以轻度和中度为主,水蚀荒漠化以中度和重度为主,盐渍化以极重度为主。20世纪80年代末荒漠化程度最轻,2005年最重。监测期内,研究区荒漠化面积年平均增长率为0.35%。其中,风蚀荒漠化和盐渍化均呈增加趋势,水蚀荒漠化呈减少趋势,年均变化率分别为0.36%、0.97%和-0.06%。未荒漠化和荒漠化土地之间、不同程度荒漠化土地之间转化比较普遍,导致荒漠化程度不断加重。荒漠化程度由1989年的0.308升高为2005年的0.324;以极重度荒漠化面积计,年均荒漠化变化速率为0.103%,年均扩展面积2 088.62hm2。

Desertification,as a major global environmental problems,has aroused the world attention.This paper takes the TM images in 1989,2000 and 2005 of the study area as the basic data,studies on the basis of remote sensing interpretation signs in the field of desertification,extracts information through human-computer interaction,establishes spatial database of desertification.The results showed that,in the study period,the desertification of the study area was very serious and deteriorating.The average rate of desertification is nearly 80%.The ratio of wind erosion desertification,water erosion desertification and salinization area is roughly 65：10：5.Most of wind erosion desertification is mild and moderate,the one of water erosion desertification is moderate and the one of salinization desertification is mainly severe.In the late 1980s,the degree of desertification was the lightest,and it was severest in 2005.In monitoring period,the average annual growth rate of desertification in the study area is 0.35%.Among them,the wind erosion and salinization water erosion desertification showed an increasing trend,while the water decreasing showed decreasing trend.The average annual rate of change was 0.36%,0.97% and-0.06% respectively.The conversion of non-desertification land and desertification land,among lands of different levels desertification is relatively common,resulting in the increasing of desertification.The desertification grade rose from 0.308 in 1989 to 0.324 in 2005.Calculated by extreme-desertification area,the average annual rate of desertification process was 0.103% and the average annual expansion area was 2088.62 hm2.