基于RSEI的黄河流域生态环境质量监测与驱动因素分析

RSEI-based analysis on eco-environment quality monitoring and driving factors of Yellow River Basin

生态环境质量评价是开展黄河流域生态环境保护和生态文明建设的重要基础。针对现有研究多利用统计数据或者单一指标探讨黄河流域生态环境状况难以揭示黄河流域内部生态系统的复杂性和整体性这一问题,为了快速、系统地监测黄河流域的生态环境质量,利用谷歌地球引擎(Google Earth Engine,GEE)遥感大数据处理平台提供的MODIS产品反演得到了2001—2021年黄河流域遥感生态指数(Remote sensing ecological index,RSEI),并基于Theil-Sen斜率估计和Mann-Kendall(MK)趋势分析探究了黄河流域生态质量演变趋势,并探究了21 a间黄河流域土地利用变化情况和温度、降水和风速对RSEI影响情况。结果表明:(1)绿度、热度、湿度、干度的第一主成分贡献率均高于75%,即基于第一主成分提取的RSEI能较好地表征黄河流域生态环境状况。(2)黄河流域生态环境空间分布异质性较大,整体表现为改善、变差和改善的过程。其中,2001—2010年间黄河流域3.09%区域为退化趋势,50.01%区域变化不明显,46.79%区域为轻微改善趋势。2011—2021年黄河源区、河套平原、壶口和三门峡地区均呈轻微改善趋势,黄土高原中部地区为轻微退化趋势。(3)2000—2005年耕地面积减少主要归结于草地、建设用地和未利用地的增加;2005—2015年间草地面积减少,林地和耕地面积分别增加;2015—2020年草地、林地和建设用地面积增加,耕地和未利用地面积减少。(4)RSEI与风速为正相关区域集中在海拔较高的刘家峡以西地区,为负相关性的区域在黄土高原地带。气温与RSEI主要以正相关为主,但在黄河流域的内蒙古地区和陕西以负相关为主。降水与RSEI主要以正相关为主,仅在约古宗列渠和龙羊峡部分区域为负相关。研究成果可为黄河流域生态环境质量的评估和改善提供实践参考和理论支撑。

Ecological environment quality assessment is an important foundation for ecological environment protection and ecological civilization construction in the Yellow River Basin. Aiming at the problem that the discussions on the eco-environment situation of the Yellower River Basin made by the existing studies are mostly relied on the relevant statistical data or single index, and then the complexity and integrity of the inner ecosystem of the Yellow River Basin are difficult to be revealed, the remote sensing ecological index(RSEI) of the Yellow River Basin from 2001 to 2021 is obtained by the inversion with MODIS products provided by Google Earth engine(GEE) remote sensing big data processing platform, so as to quickly and systematically monitor the eco-environment quality of the Yellow River Basin, and then the evolution trend of ecological quality within the Yellow River Basin is explored based on Theil-Sen slope estimation and Mann Kendall(MK) trend analysis, while the influences from land use change as well as temperature, precipitation and wind speed on RSEI within the Yellow River Basin in the period of the 21 years are explored as well. The results show that:(1) the contribution rates of the first principal components of greenness, heat, humidity and dryness are all higher than 75%, that is, the RSEI extracted based on the first principal component can better represent the eco-environment situation of the Yellow River Basin;(2) the spatial distribution of the eco-environment in the Yellow River Basin is quite heterogeneous with the overall performance of the process of improvement, deterioration and improvement, in which 3.09% of the area exhibits a degradation trend, the regional change of 50.01% of the area is not so obvious and 46.79% of the area shows a trend of slight improvement. The Yellow River source area, Hetao Plain, Hukou and Sanmenxia areas all present the trends of slight improvement from 2011 to 2021, while the central part of the Loess Plateau exhibits a trend of slight degradation;(3) the decrease of cultivated land from 2000 to 2005 is mainly due to the increases of grassland, construction land and unused land. From 2005 to 2015, the area of grassland is decreased with the respective increases of the areas of forest land and cultivated land, while the areas of grassland, forest land and construction land are increased with the decreases of the areas of cultivated land and unused land from 2005 to 2015;(4) the areas with positive correlation between RSEI and wind speed are concentrated in the west regions of Liujiaxia Gorge with higher altitude, while the areas with negative correlation are within the zone of Loess Plateau, but the areas of the Inner Mongolia and Shaanxi Province in the Yellow River Basin are mainly negatively correlated. Precipitation is mainly positively correlated with RSEI and is only negatively correlated in some areas of Yoguzonglie Canal and Longyangxia Gorge. The study results can provide practical reference and theoretical support for the assessment and improvement of eco-environment quality in the Yellow River Basin.