基于NDVI的藏北地区草地退化时空分布特征分析

发布时间：2018-08-27 13:11

【摘要】：本文以藏北地区为研究区域,基于归一化植被指数(NDVI)反演草地植被盖度,以植被盖度作为判断草地退化的标准,综合计算藏北地区2000-2010年逐年草地退化指数(grassland degradation index),定量揭示藏北地区草地退化的时空分布规律。结果表明,截至2010年,藏北地区草地退化现状仍然较为严重,退化草地的面积占全区面积的58.2%。其中,重度退化和极重度退化草地面积的比例分别为19.0%和6.5%,区域草地退化指数为1.97,接近中等退化水平。分区结果显示,藏北地区中部、东部、北部草地退化情况较为严重,均处于中等退化等级,西部地区的退化情况最轻,处于轻度退化等级。分析2000-2010年藏北地区全区及各个分区的草地退化趋势表明,只有北部地区有减缓趋势;2000-2010年间与1981-1985年间对比结果显示,重度退化及极重度退化草地面积比例上升幅度较大。2000-2010年间藏北地区平均草地退化指数为1.84,草地退化等级在轻度退化到中度退化之间波动。
[Abstract]:In this paper, based on the normalized vegetation index (NDVI), the grassland vegetation coverage is inversed, and the vegetation coverage is taken as the criterion to judge grassland degradation. The temporal and spatial distribution of grassland degradation in northern Tibet is revealed by synthetically calculating the annual grassland degradation index (grassland degradation index),) from 2000 to 2010. The results showed that the present situation of grassland degradation in northern Tibet was still serious up to 2010, and the area of degraded grassland accounted for 58.2% of the whole area. Among them, the proportion of degraded grassland area was 19.0% and 6.5%, respectively, and the regional grassland degradation index was 1.97, which was close to the moderate degradation level. The results showed that the degradation of grassland in the central, eastern and northern regions of northern Tibet was more serious, all of them were in the moderate degradation grade, and the degradation in the western region was the least, which was in the mild degradation grade. According to the analysis of grassland degradation trend in the whole region and various subzones of northern Tibet from 2000 to 2010, the results show that only the northern region has the tendency to slow down, and the comparison between 2000-2010 and 1981-1985 shows that, From 2000 to 2010, the average grassland degradation index in northern Tibet was 1.84, and the grassland degradation grade fluctuated from mild to moderate degradation.
【作者单位】：中国农业科学院农业环境与可持续发展研究所;农业部农业环境与气候变化重点实验室;北京师范大学环境学院;西藏自治区那曲地区草原站;
【基金】：国家科技支撑课题(2012BAC01B02) 国家自然科学基金项目(31170460) 西藏那曲地区与中国农业科学院合作项目资助
【分类号】：S812.6

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