近40a海西蒙古族藏族自治州沙漠化时空变化及驱动力分析

通过对海西蒙古族藏族自治州1975—2015年Landsat卫星遥感影像进行解译,获取了该州近40 a沙漠化土地动态变化特征。结果表明:(1)研究区近40 a沙漠化土地面积先增加后减少,1975—1995年为沙漠化发展时期,1995—2015年为沙漠化逆转时期,1995年沙漠化程度最高,沙漠化土地面积17 1591.42 km~2;(2)沙漠化变化集中在研究区高海拔地区,柴达木盆地内部一直以重度沙漠化为主;沙漠化明显发展和明显逆转分别集中在1985—1995年和1995—2005年;(3)各类型沙漠化土地重心迁移总体表现为1975—1995年向东迁移,1995—2015年向西折返。通过对海西蒙古族藏族自治州沙漠化时空变化的驱动因素进行分析,表明人为因素是造成20世纪90年代之前研究区沙漠化显著发展的主导因素,而气候因素和人为因素共同促进了之后的沙漠化逆转。

Spatial-Temporal Evolution and Driving Force Analysis of Desertification of Haixi Mongolian and Tibetan Autonomous Prefecture in Recent 40 Years

Based on the interpretation of Landsat satellite remote sensing images of Haixi Mongolian and Tibetan Autonomous Prefecture from 1975 to 2015 ,and the dynamic changes of desertification land in recent 40 years were collected. The results showed that: (1) Desert land in study area increased at the beginning and decreased finally in lastest 40 years. Desertification developed significantly of 1975-1995 while as reversal during 1995 and 2015. It had reached the highest level for desertification in 1995, and the area was 171591.42 km2; (2) Desertification changes concentrated in high altitude of study area and occurred seriously in the interior of Qaidam basin; Additionally, desertification significantly developed and retreated on 1985-1995 and 1995-2005, respectively; (3) the main part of various types desertification land shifted eastward in 1975-1995 while westward turned during 1995-2015. According to the driving factors analysis on the temporal and spatial changes of desertification in Haixi Mongolian Tibetan Autonomous Prefecture, it showed that human activities was the dominant factor on the remarkable development of desertification before1990s, while the climate and human factors promoted the reversal of desertification after that.