2000-2010年鄂尔多斯地区沙漠化动态及其气候变化和人类活动驱动影响的辨识

以2000-2010年近10 a来鄂尔多斯地区沙漠化过程为研究对象, 在利用MODIS数据对沙漠化动态进行监测的基础上, 综合分析沙漠化逆转和发展地区气候变化和人类活动引起的NPP变化趋势, 定量评估近10 a来鄂尔多斯地区沙漠化动态及其与气候变化和人类活动间的关系. 结果表明: 2000-2010年间, 尽管鄂尔多斯地区沙漠化面积没有明显变化, 但是沙漠化程度呈现整体逆转的态势, 其中逆转的沙漠化土地面积达47 057 km²(占鄂尔多斯地区土地总面积的54.2%), 比发展的沙漠化土地面积高出近3倍. 气候变化是近10 a来鄂尔多斯地区沙漠化逆转的主导因素, 主要归因于2006年来降雨量的增加以及近10 a来春季风速的减小, 围封禁牧、 退耕还林(草)等政策的实施及其与有利气候条件的耦合进一步加快了区域沙漠化的逆转. 人类活动是导致近10 a来鄂尔多斯地区沙漠化发展的主要因素, 主要归因于部分地区生态保护政策的落实不力以及区域资源开发引起的环境破坏, 完全由人类活动引起的沙漠化发展主要分布鄂尔多斯的北部地区.

The Desertification Dynamics in Ordos from 2000 to 2010 and Their Relationship with Climate Change and Human Activities

Ordos is one of the regions that seriously suffered from desertification in China. Carrying out the research on the desertification dynamics monitoring and its relationship with driving forces in Ordos has significance for understanding the process of desertification, making and evaluating the policies for desertification rehabilitation. In this paper, based on using the MODIS data to monitor the desertification dynamics in Ordos from 2000 to 2010, the changing trends of net primary productivity due to climate change and human activities for the lands experienced desertification reversion and expansion is analyzed, and the desertification dynamics in Ordos from 2000 to 2010 and their relationship with climate change and human activities are quantitatively assessed. It is found that the area of desertification land in Ordos did not changed obviously from 2000 to 2010, but the degree of desertification reversed significantly, and area of lands experienced desertification reversion reached 47 057 km² (accounting for 54.2% of the total area of Ordos), which was almost three times higher than that of desertification expansion. Climate change was the dominated factor that induced the desertification reversion from 2000 to 2010, which almost could be attributed to the increasing precipitation and the decreasing of wind speed in spring from 2000 to 2010. Also the implement of ecological protection policies, such as rangeland enclosure and grain for green and its' coupling with good climate condition, accelerated the desertification reversion. Human activities was the dominant factor that induced the desertification expansion from 2000 to 2010, which mainly attributed to the implementation of those ecological protection policies ineffective and the environment damage due to development of energy and mining industries, and the lands with desertification expansion totally induced by human activities mainly distributed in the north of Ordos.