Fusion Of GPS And Optical Remote Sensing To Detect Greenland Study On The Status Of Island Snow Cover

As an important fresh water resource on the earth,snow cover is also one of the key components of the hydrological system.It affects the water cycle and the atmospheric circulation,and its spatial and temporal variations play a key role in the atmospheric circulation.Relevant data show that nearly 10% of the entire surface of the globe is covered by permanent snow or thick glaciers,33% of the region has seasonal snow,and the distribution of transient snow is relatively scattered and random.In semi-arid and arid regions,the water generated by melting snow plays an important role in local ecological resources and promotes the development of agriculture and animal husbandry to some extent.In this paper,Greenland island is taken as the research area.With the help of research results of scholars from various countries,the snow depth of three typical GPS stations on Greenland island is obtained based on the principle of GNSS-MR technology to extract snow depth.The feasibility of ground-based GNSS technology for polar ice and snow environment monitoring is mainly studied.At the same time,the interannual variation and seasonal variation of the Greenland on snow cover were studied and analyzed based on the product data of Landsat and MODIS.The major contents and consequence of my paper are as follows:1.At first,starting from the multi-path effect of GNSS,the basic principle of snow cover parameter extraction by GNSS-MR technology is expounded.Taking the GPS monitoring station on Greenland island as the research object,three stations with large spacing and long data span were selected,and the snow cover depth of the three GPS stations was extracted based on the GNSS-MR technology.Due to the influence of the island's special climate and terrain,the GNSS-MR results are quite different from the measured snow depth.By analyzing the GPS velocity field distribution on Greenland island and the time series of the U direction component of the three stations,the snow depth value of GNSS-MR was corrected,which was significantly improved compared with the previous results.The experimental results show that the ground-based GPS can be used for the environmental monitoring of polar ice and snow in Greenland and has a great application prospect.2.Using Landsat data to analyze the inter annual change of snow distribution area of Greenland island,the results show that the snow area of Greenland island is decreasing,and the change of snow at different altitudes is different.The snow change trend of low mountain area is faster,while that of plain area and high mountain area is slower.3.The seasonal change of snow area distribution in Greenland island is obtained by MODIS product data.In terms of seasonal change,the snow change in Greenland island shows a bimodal pattern,i.e.the law of increase decrease increase.The snow cover area in autumn is the smallest,the snow cover area in spring is the largest,and the temperature is the main factor affecting the bimodal pattern of snow area change in low mountain and high mountain areas.