Abstract:

Based on the MODIS remote sensing inversion data from 2001-2013, this paper studied the desertification and characteristics of its seasonal variation in Hetao area through analyzing the land cover types, leaf area index (LAI), normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). The results showed that from 2001 to 2013, the overall land cover of vegetation in Hetao area was getting better with cultivated land area increasing from 4218 km² in 2001 to 20470 km² in 2013, the average LAI increasing from 0.130-0.335 in 2003 to 0.182-0.405 in 2013, and the overall trend of average NDVI and EVI were increasing year by year, from 0.142 and 0.095 in 2001 to 0.193 and 0.116 in 2013 respectively. Moreover, the quality of vegetation growth per unit area was increasing as well. In addition, according to the characteristics of the seasonal distribution of NDVI, food crops with two harvests a year began to be largely planted in Bayannur League, northern Hetao area around the year of 2013. However, the study also found that the vegetation cover index in Hetao area was still low and the desertification in northern and southwestern Hetao area had deteriorated. Therefore, the ecological environment problems will easily appear without effective measures.

Key words: Hetao area, desertification, land cover types, LAI, NDVI, EVI

摘要：

基于2001—2013年MODIS遥感反演数据, 通过对土地覆盖类型、叶面积指数(LAI)、归一化植被指数(NDVI)和增强植被指数(EVI)4个方面的分析, 研究河套地区的荒漠化情况及其季节变化特点。结果表明, 2001—2013年, 河套地区整体植被覆盖转好, 其中, 耕地面积从2001年的4218 km² 增大到2013年的20470 km², LAI平均值从2003年的0.130~0.335增大到2013年的0.182~0.405, 平均NDVI和EVI逐年总体增大, 分别从2001年的0.142和0.095增大到2013年的0.193和0.116, 而且, 单位面积上的植被生长质量也在加强。此外, 归一化植被指数季节分布特点显示, 河套地区北部巴彦淖尔盟2013 年左右开始大面积种植一年两季粮食作物。但是, 研究结果表明河套地区植被覆盖指数仍较低, 北部和西南部荒漠化情况加剧, 若不采取有效措施, 极易出现“沙进人退”的生态环境问题。

关键词: 河套地区, 荒漠化, 土地覆盖类型, 叶面积指数(LAI), 归一化植被指数(NDVI), 增强植被指数(EVI)