由于科尔沁沙地的生态文明建设和城镇化的快速推进,及时的对生态环境质量进行监测显得尤为重要。利用2000年、2006年、2012年、2018年奈曼旗的Landsat-5 TM\〈 OLI数据,计算绿度(NDVI)、湿度(WET)、干度(NDSI)和热度(LST)4个生态指数,基于主成分分析方法构建RSEI生态指数模型,对奈曼旗18年来生态环境质量变化进行了动态监测与评价。结果 表明:绿度和湿度对奈曼旗生态环境质量起正面作用,干度和热度起负面作用; 2000—2018年RSEI均值增长0.232 6,涨幅76.49%; 生态环境质量差和较差的区域面积共减少了1 654.06 km2,优等级的区域面积增长高达1 048.17 km2,其中差和较差区域主要分布在中部沙区; 研究期间生态环境质量改善区域面积均大于退化区域,改善面积在2000—2006年达到峰值,面积高达5 327.6 km2,占总面积的65.77%,退化区域主要集中在中部沙区; 奈曼旗生态环境整体呈逆转趋势,并趋于稳定,但局部仍会出现退化现象。
Due to ecological civilization construction and rapid urbanization in Horqin Sandy land,timely monitoring of ecological environment quality is particularly important. Normalized difference vegetation index(NDVI), wetness index(WET), build-up and soil index(NDSI)and land surface temperature(LST)in Naiman Banner were calculated by using Landsat 5/TM and Landsat 8/OLI images in 2000, 2006, 2012 and 2017. Principal component analysis was used to construct RSEI ecological index model to dynamically monitored and evaluated the environmental quality changes in Naiman Banner from 2000 to 2018. The results show that NDVI and WET played the positive roles in the eco-environment quality of Naiman Banner, while NDSI and LST had the negative effect; the RSEI mean value increased 0.232 6 from 2000 to 2018, and the increase rate was 76.49%; the area of the poor and the relatively poorer co-environment quality reduced by 1 654.06 km2, the excellent grade increased by as much as 1 048.72 km2 and the poor and the relatively poorer areas mainly distributed in the middle sand area; during the study period, the improvement area of the eco-environment quality was larger than that of degradation area, the improvement area reached its peak during the period from 2000 to 2006, reaching 5 327.6 km2 and accounting for 65.77% of the total area, the degradation area mainly concentrated in the middle sand area; the overall eco-environment of Naiman Banner showed the reversed trend and tended to be stable, but local degradation still occurred.
