| The Antarctic ice sheet is the world's largest ice sheet,covering an area of 13.98 million square kilometers,with an average thickness of 2000-2500 m,a maximum thickness of 4800 m,and a total volume of about 28 million cubic kilometers,but the Antarctic ice sheet material is accelerating in recent years Loss,the environment on which human beings depend is facing a severe test.Ice shelf surface melting is one of the main causes of ice shelf material loss.Ice surface melting has an important impact on ice sheet material balance and ice shelf stability.Therefore,the research of Antarctic ice surface melt water has important scientific significance and practical application value.Based on the Landsat series of remote sensing data,this paper takes the Larsen ice shelf and the Emory ice shelf as the research area,carries out the research on the remote sensing extraction method of ice surface melt water,analyzes the differences in the spectral characteristics of the ice surface melt water,and analyzes the three water body index methods.A comparative analysis was carried out,and the extraction results based on Landsat data were verified using Sentinel 2 optical image data with a resolution of 10 meters,and a remote sensing extraction method of Antarctic ice surface meltwater information based on the normalized water body index method was constructed.Finally The data on the temporal and spatial distribution of the melting ice in the Antarctic Larsen Ice Shelf and the Emory Ice Shelf in summer from 2010 to 2019 were extracted,and the weather data of the two meteorological stations were used to analyze the impact of the dynamic changes of the melting ice on the ice surface.Based on the BEDMAP2 ice surface elevation data,the spatial distribution of the melt water on the Larsen ice shelf and the Emery ice shelf was analyzed.The main research conclusions are as follows:(1)Analyze the difference in the spectral characteristics of ice surface melt water,compare the experiments with several commonly used water body index methods,and establish a remote sensing extraction method for the ice surface melt water of the typical Antarctic ice shelf based on the normalized water body index.Using the 2017 Sentinel-2 data with a resolution of 10 meters,the Lassen ice shelf was verified based on the Landsat data.The relative error of the extraction area of the two was 3.82%,ensuring the proposed remote sensing extraction of the ice surface melt water.The method meets the accuracy requirements.(2)Based on the extraction of Landsat series of remote sensing images,the temporal and spatial distribution vector data of the ice surface melt water of the Larsen Ice Shelf and the Emery Ice Shelf from 2010 to 2019 were obtained,and the thematic map of ice surface melt water distribution was produced.The interannual variation curves of the melting surface area of two typical ice shelves are drawn,and the reasons for the changes in the melting surface of the ice surface are analyzed.(3)Combined with meteorological data,the interannual climate change trends of the Larsen Ice Shelf and the Emery Ice Shelf were discussed,and the dynamic changes of ice surface melt water and the interaction with meteorological factors were analyzed.Air temperature is the main factor affecting the change of ice surface melt water area,and wind speed has little effect on ice surface melt water.(4)Combined with the elevation data,the distribution of the melt water of the Larsen ice shelf and the Emery ice shelf with the elevation is analyzed.The ice surface at high altitude melts to form ice surface melt water.When the ice surface melt water overflows,it flows along the high terrain to the low terrain area,accelerating the convergence of the ice surface melt water at the low altitude,so the ice surface Melt water mainly gathers in low-altitude areas,but ice-melt water in middle-altitude areas tends to increase. |
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