Fusion of historical survey data and remote sensing to analyze the spatiotemporal variation of altitudinal belts in the Kunlun Mountains during 2000-2020

基于遥感和历史调查数据的昆仑山地垂直带谱时空变化研究

The spatiotemporal variation in the altitudinal belts in the Kunlun Mountains reflects the natural geographical environment of the arid areas and is essential for constructing a dynamic change system of altitudinal belts in central and western China.In this study,we compiled the altitudinal belt spectra for three typical peaks(Amne Machin Mountain,Muztag Mountain,and Kongur Peak from east to west)using the Google Earth Engine(GEE),Landsat,and NASADEM.Considering historical vegetation surveys,we analyzed spatiotemporal patterns in the Kunlun Mountains for 2000,2010,and 2020.The results reveal that 1)the altitudinal belt spectra of the Kunlun Mountains exhibited a trend of complexity,simplicity,and complexity,with the number of altitudinal belts decreasing from six to three and then increasing to four from east to west.The dominant belt transitions from an alpine meadow belt to alpine desert steppe and montane desert steppe belts,excluding the nival belt.2)The upper limits of altitudinal belts are higher on sunny slopes than on shady slopes in the Kunlun Mountains,with an average altitudinal difference of 77.90 m.3)From 2000 to 2020,there was a widening trend in vegetation and desert belts,accompanied by glacier shrinkage.The range of glacier belts(nival and subnival)decreased by an average of 64 m,resulting in a 64 m rise in the upper limit of the alpine desert steppe belt in the Kunlun Mountains.This suggests drying and warming trends at high altitudes in the Kunlun Mountains in the study period.