Multi-source Remote Sensing Monitoring And Analysis Of The Interannual Variation Of Hailuogou Glacier Tongue

Mountain glaciers are the product of the joint action of climate and terrain,which can not only provide a large amount of fresh water resources,but also benefit my country’s economic construction and development.However,with the impact of global warming,the movement of most mountain glaciers in my country has become more active,causing a series of sudden natural hazards such as ice avalanches,glacier leaps,and ice lake collapses.This has brought a huge impact on my country’s economic construction and people’s lives.Therefore,using multi-source remote sensing data to monitor glaciers and explore the response between interannual changes of glaciers and climate change can provide guarantees for the normal operation of various important fields such as the ecological environment and social economy in our country.In this paper,Hailuogou glacier tongue is taken as the research area,based on Landsat,Sentinel-1A,digital elevation model and UAV images and other multi-source remote sensing data,combined with GIS technology,the glacier area,length,surface elevation and glacier area of Hailuogou glacier tongue are analyzed.Monitoring changes in surface velocity and exploring the interannual variability of glaciers in response to climate change.The main contents and achievements of the paper are as follows:(1)The boundary,area and length of the Hailuogou glacier tongue area were extracted.The boundary of Hailuogou glacier tongue was extracted by visual interpretation,and the boundary was corrected by UAV images and Google Earth to obtain the boundary,area and length of the glacier in five periods in 2000,2005,2010,2015 and 2022.The results show that the total area of the Hailuogou glacier tongue in 2022 will be 1.57 km2,and the length will be 4330 m.From2000 to 2022,the Hailuogou glacier tongue showed a shrinking trend,with a total decrease of0.58 km~2 in area,with an average annual change rate of-1.23%,and a decrease of 392 m in length,with an average annual change rate of-0.38%.The average annual change rates of area in the four time periods are-0.28%,-0.94%,-1.39%,-2.36%,respectively.The length change rates are-0.21%,-0.35%,-0.43%,and 0.52%,respectively,and the glacier tongue is in a state of accelerating ablation as a whole.The area of the Hailuogou Glacier Tongue is mainly distributed between 3400-3500 m above sea level,the south and east oriented glaciers have the largest area,but the northwest oriented glacier area has the largest change rate.(2)The surface elevation change of the Hailuogou glacier tongue was estimated.Based on the registration of SRTM-X and Tan DEM data,the surface elevation change of the Hailuogou glacier tongue area during 2000-2015 was estimated.The results show that the average elevation of the ice tongue was 3404.35 m in 2000 and 3384.46 m in 2015.The average elevation change is-15.26 m,and the rate of change is-1.02 m/a.Therefore,the Hailuogou glacier tongue area is in a thinning state as a whole.(3)Obtained the surface velocity of the Hailuogou glacier tongue area.Based on the Sentinel-1A data,the surface velocity of the Hailuogou glacier tongue from 2018 to 2021 and the impact of the 9?5 Luding Earthquake on the Hailuogou glacier tongue were obtained using pixel offset tracking technology and interferometry.The results show that the surface flow velocity of glaciers in this area is 0.0019 mm/d in spring,0.0299 mm/d in summer,-0.0238 mm/d in autumn,and 0.0019 mm/d in winter in 2021,and the surface flow velocity during the ablation period is greater than that in other periods.The annual surface velocity in 2018-2021 is 0.1486mm/d,-0.0021 mm/d,0.0028 mm/d and 0.0116 mm/d,respectively.The surface velocity of the Hailuogou Glacier Tongue as a whole is not fast.In addition,the 9?5 Luding Earthquake had a certain impact on the Hailuogou glacier tongue area,but the overall impact was not significant.(4)Combined with the data of meteorological stations,discuss the response relationship of glacier changes to temperature and precipitation changes.From 2000 to 2022,the temperature in the Hailuogou glacier tongue area increased significantly,while the precipitation decreased slightly.In 2021,the temperature and precipitation during the ablation period are higher than other periods.Therefore,the analysis suggests that the rise in temperature is likely to be the main climatic factor leading to changes in the area,length,and surface elevation of the Hailuogou Glacier Tongue.In addition,the glacier surface velocity in this area has no direct relationship with the temperature and precipitation changes.