Research On Mountain Glacier Mass Balance Based On Remote Sensing Data

Glaciers are a natural indicator of climate change.Glacier mass balance is a key factor linking glacier fluctuations and climate change,and is a direct response of glaciers to climate change.Therefore,the observation and simulation of the glacier mass balance and the research on the relationship between the mass balance and the climatic factors are carried out to reveal the melting mechanism of glaciers and the law of the water cycle,which can provide a scientific basis for the investigation and assessment of water resources in the area where it is located.In the study of glaciers/snow cover,remote sensing technology is widely used by scientists to monitor the global changes of the cryosphere because of its macroscopic,comprehensive,dynamic,and fast advantages.Monitoring provides a useful research tool.This article takes Urumqi Glacier No.1(hereinafter referred to as Urumqi Glacier No.1),Laohugou Glacier No.12,and Qiyi Glacier as examples,based on the SNOWMAP algorithm and accumulation area area ratio method,using Landsat and sentry remote sensing data,and digital elevation model(DEM)and field observation data(mass balance,equilibrium line altitude,and accumulation area ratio)and other data systems completed the monitoring of glacier equilibrium line altitude,accumulation area ratio,and mass balance during the study period.Based on this,combined with data such as temperature and precipitation,the response of glacier mass balance changes to climate was analyzed,and the feasibility and applicability of the remote sensing method and the area ratio method of accumulation area were analyzed and demonstrated in this area.explore.Studies have shown that the area ratio of the accumulation area at the end of the ablation period has a good indication of the mass balance.Based on this,using the field measured glaciers data of the Urumqi Glacier No.1 from 1960 to 2015,the relationship between the area ratio of the accumulation area and the mass balance was established.The empirical model obtained is used to estimate the mass balance of Tianshan Glacier No.1.And under the same climate model,this empirical model is also suitable for estimating the mass balance of Qiyi Glacier and Laohugou Glacier No.12.The main conclusions are as follows:(1)Taking Glacier No.1 as an example,based on the results of field observations of the equilibrium line altitude,the accumulation area ratio,and the equilibrium line altitude and the accumulation area ratio estimated by remote sensing,a regression analysis was performed on the two.Above,the correlation between the two is good,indicating that the snow line altitude estimated by remote sensing can indicate the change of the equilibrium line altitude.(2)Taking Glacier No.1 as an example,the mass balance simulated based on the area ratio method of the accumulation area can reflect its interannual change characteristics and has good consistency.Statistical analysis shows that the correlation coefficient is 0.88,and the determination coefficient(R~2)is approximately 0.77,the root mean square error(RMSE)is about 165.44 mm w.e..(3)During the study period,the mass balance of Glacier No.1 showed a downward trend and a negative balance.The cumulative mass balance reached-8290.7 mm w.e.,and the average annual mass balance was between-267~-1034mm w.e..From 2002 to 2012,the melting rate of Glacier No.1 was relatively slow,and the melting rate accelerated in 2012-2018;the cumulative mass balance reached-5840 mm w.e.,and the average annual mass balance was between 105.8 to-1147.1mm we;Laohugou The mass balance of Glacier No.12 showed a downward trend during the study period from 2013 to 2018.The glacier was in a receding state.The cumulative mass balance reached-1616.1 mm w.e.,and the average mass balance was between 206 and-480.7 mm w.e.(4)Taking Glacier No.1 as an example,it can be seen from the sensitivity of mass balance to summer temperature and annual precipitation that summer temperature is the main climatic factor affecting the change of mass balance.If the annual precipitation is constant,and the summer temperature rises(or decreases)by1?,the mass balance will decrease(rise)by about 144.9 mm w.e.;if the summer temperature is constant,the annual precipitation increases(or decreases)by 100 mm,then the mass balance will increase(or decrease)about 35 mm w.e..