Snow Cover Change In Valley Topography And Its Response To Climate In West Kunlun Mountains From 2002 To 2018

Snow cover is an important part of the Cryosphere and one of the most active surface cover types in the world,which is of great significance to the global water cycle.In the arid area of Northwest China,snow cover is not only an important solid fresh water resource,but also an important material basis for the development of mountain glaciers.Therefore,it is of scientific significance to study the relationship between snow cover and climate change in northwest arid area.The West Kunlun Mountains are located in the inland area of Northwest China.There are many ice and snow water supply rivers in the region.The snow storage in winter is an important source of fresh water supply for Hotan City,Yutian County,Yecheng county and Pishan County in spring and summer.Previous studies on the response of snow cover change to climate in the West Kunlun Mountains are mostly regional integration analysis or basin based analysis,lacking quantitative analysis and significance evaluation of the relationship between snow cover change and temperature and precipitation in different regions.Therefore,it is helpful to understand the response of snow cover change to climate change by analyzing the temporal and spatial variation of snow cover and its climatic factors in the West Kunlun Mountains.In addition,the West Kunlun Mountains is an area where glaciers are developed in the polar continental type.There are a lot of valley glaciers in the area due to the good ice and snow storage in the valley topography.However,there are still great differences between the remote sensing interpretation results of glacier area change and the calculation results of glacier mass balance so far,The amount of snow cover in winter is an important factor affecting the development and material balance of glaciers in the West Kunlun Mountains.Therefore,studying the temporal and spatial variation trend of snow cover in winter in the West Kunlun Mountains can provide more information for the study of glacier development and change in the West Kunlun Mountains.Therefore,this paper takes the West Kunlun Mountain as the research area,takes alos elevation data as the basic analysis data,uses MATLAB software to extract the valley geomorphic units in the research area,and uses Google Earth software to test the extraction results,and finally extracts 1303 Valley geomorphic units.Secondly,combined with MODIS Snow Cover data(MOD10A1 and MYD10A1 V6 version of global daily snow cover data),the monthly variation trend of snow cover index of Valley geomorphic units in the study area is calculated,and the snow increase season is determined from September to April of the next year.The temporal and spatial variation trends of snow index mean value,maximum value of snow index and proportion of snow days in snow season in the valley during 17 years were analyzed.Finally,combined with the monthly mean temperature and monthly total precipitation data of era5 meteorological data(the fifth generation of global climate reanalysis monthly data set),the influence and significance of temperature and precipitation on snow change in snow season Valley in different regions are quantitatively calculated,and the response of snow change in valley geomorphology area of West Kunlun Mountains to climate change in snow season is discussed,This paper attempts to explore the corresponding relationship between the temporal and spatial changes of snow cover and the regional Glacier Mass Balance in snow season.The main conclusions are as follows(1)In winter,there is a large spatial-temporal heterogeneity of snow cover change in the West Kunlun Mountains.In the snow season,the overall snow cover in the Valley shows a weak downward trend.In terms of spatial differences,the snow cover in the West and central regions shows a downward trend,while that in the East and southwest regions shows an upward trend.(2)The winter precipitation in the West Kunlun Mountain area shows a decreasing trend,with the spatial distribution characteristics of high in the West and low in the East,high in the north and low in the south.The overall temperature showed an upward trend,with the spatial distribution characteristics of high in the East and low in the west,high in the north and low in the south.MK mutation test found that the average temperature increased abruptly in 2011,the maximum temperature increased abruptly in 2010,and the minimum temperature increased abruptly in 2012.(3)The response of snow cover change to climate change in the West Kunlun Mountains in winter shows four stages in time and gradually increases from southeast to northwest in space.In the significance analysis,the temperature has a significant effect on snow cover in the valley in almost all the research areas,and the precipitation only shows a high significance in the northern low-altitude mountainous areas.In this paper,the temporal and spatial variation characteristics of snow cover in West Kunlun Mountain valley in winter from 2002 to 2018 were studied,and the temporal and spatial distribution and variation trend of winter temperature and precipitation were analyzed.The results show that the response of snow cover change to climate change is different in different regions,which provides new data for the study of snow cover change in West Kunlun Mountains.