Spatio-temporal Variation Of Snow Cover In Northern Xinjiang Based On Active And Passive Satellite Remote Sensing Technology

Snow cover is the most widely distributed element in the frozen circle,and its existence and change have important influence on energy exchange and hydrological cycle.In semi-arid and arid areas,snow melt water plays an important role in regional ecological environment,and promotes the development of agriculture and animal husbandry to a certain extent.Real time and accurate monitoring of snow area distribution and regional snow depth is of great significance to climate change,hydrological application,disaster prevention and mitigation.Therefore,in this paper,taking Northern Xinjiang as the research area,using GIS spatial analysis technology,combined with MOD10A2,the snow area parameters of Northern Xinjiang from 2016 to 2020 were extracted,and the temporal and spatial variation of snow area and snow days were analyzed.Secondly,using D-InSAR technology and sentinel-1A,the inversion method of snow depth change in Jun Tang Hu basin in Northern Xinjiang from January 30 to February 11,2017 is studied,and the temporal and spatial variation law and influencing factors of snow depth are analyzed.Through the above research,the following conclusions are drawn:1.There are obvious inter annual and intra annual seasonal differences in the snow cover change trend in Northern Xinjiang.The snow cover area presents a "U" shaped bimodal change,and the inter annual accumulation and ablation have obvious periodicity,which is greatly affected by altitude;The proportion of snow cover in winter(83.5%)> autumn(29.4%)> spring(21.1%)> summer(3.4%);The change of snow cover area is mainly determined by temperature,and there is a significant negative correlation between them.2.The distribution of snow days in Northern Xinjiang is greatly affected by the terrain,showing a north-south distribution surrounded by the middle,which is very consistent with the terrain distribution of Northern Xinjiang;The results show that the snow cover area of the snow cover days division is short-term snow cover area(53.18%),medium day snow cover area(32.39%),unstable snow cover area(7.23%),long day snow cover area(4.53%)and permanent snow cover area(2.14%);Under the background of global warming,the proportion of shortterm snow area has an increasing trend,which will lead to the increase of snow melt runoff.3.The variation of snow depth in Jun Tang Hu basin from January 30 to February 11,2017 is mainly between-3cm and 8cm;Without considering the unwrapping error,the spatial distribution of snow depth increases with the decrease of elevation,and increases from around the watershed to the mainstream domain,with the increase of 0 ? 3cm in the upstream,3 ? 8cm in the middle and lower reaches,and the increase of 6 ? 8cm near the mainstream domain in the middle and lower reaches;In addition,the results of snow depth retrieved by D-InSAR are mainly affected by decoherence and input parameters(incidence angle,snow density).