基于Google Earth Engine的三峡库区土地利用与陆表参数变化研究

Variation in Land Use and Land Surface Parameters in the Three Gorges Reservoir Catchment Based on Google Earth Engine

土地利用/覆盖变化(Land Use and Land Cover Change,LUCC)对全球有着重要影响,其已对植被覆盖、地表温度(Land Surface Temperature,LST)、反照率以及其它陆表参数产生显著影响。三峡工程自建设以来,库区的土地利用变化逐渐受到外界关注。利用欧空局300 m的土地覆盖分类数据分析三峡库区2000~2015年的土地利用变化;依托先进的Google Earth Engine(GEE)平台,获取MODIS(Moderate Resolution Imaging Spectroradiometer,MODIS)NDVI(Normalized Difference Vegetation Index,NDVI)、LST和反照率数据,并分析三者的时空变化趋势;此外,探究季节性归一化植被指数(Seasonally Integrated Normalized Difference Vegetation Index,SINDVI)与LST和反照率的关系;并分析土地利用变化对SINDVI、LST和反照率的影响。结果表明:2000~2015年,三峡库区土地利用变化显著,耕地、草地、灌木地分别减少2.4%,0.05%和0.62%;林地、水域和人造地表分别增加1.98%,0.04%和1.06%。研究期间SINDVI增加2.89,LST下降0.224℃,反照率减少0.002。总体来看,三峡库区SINDVI的空间分布格局与LST和反照率的相反,且库区大部分区域SINDVI与LST和反照率呈负相关。另外,不同土地类型对SINDVI、LST和反照率影响不同。该文系统地研究了LUCC与上述关键陆表参数的定量关系,可为更好地管理该地区自然环境和土地资源提供科学的依据。

Land use and land cover change(LUCC)has been a force of global importance,affecting the spatiotemporal variations of vegetation coverage,land surface temperature(LST),albedo and other land surface parameters.Since the construction of the Three Gorges Project(TGP)was commenced,LUCC in the Three Gorges Reservoir Catchment(TGRC)has received increasing attention.In this study,the land cover classification data with a spatial resolution of 300 m acquired from the European Space Agency(ESA)were used to analyze the land use change in the TGRC from 2000 to 2015.The Moderate Resolution Imaging Spectroradiometer(MODIS)Normalized Difference Vegetation Index(NDVI),LST and albedo data were obtained through the advanced Google Earth Engine(GEE)platform,and then their spatiotemporal patterns were analyzed.The relationships between seasonally integrated NDVI(i.e.,SINDVI),LST,and albedo were investigated,respectively.The influences of land use change on SINDVI,LST,and albedo were analyzed.Our results show that the remarkable land use change has appeared in the TGRC from 2000 to 2015.The cultivated land,grassland,and shrubland decreased by 2.4%,0.05%,and 0.62%,respectively,while the forest,waterbody,and artificial surface increased by 1.98%,0.04%,and 1.06%,respectively.During the research period,SINDVI increased by 2.89,LST decreased by 0.224℃,and albedo decreased by 0.002.The spatial distribution of SINDVI showed an increasing trend,while the LST and albedo showed declining trends.There was a negative relationship between SINDVI and LST,as well as a negative relationship between SINDVI and albedo in most areas of the TGRC.Different land use types present various effects on SINDVI,LST,and albedo.The quantitative relationships between LUCC and the key land surface parameters in the TGRC were analyzed systematically from 2000 to 2015,and the results will provide guidelines for the evidence-based policy for better management of the natural environment and land resources in the TGRC region.