15:00 〜 15:15
[ACC28-05] Glacier albedo analysis in Altai mountains, 2000-2020
キーワード：氷河、アルベド
Introduction
Mountain glaciers have been shrinking in recent years due to global warming in the world. In the Altai Mountains, glacial meltwater is essential for the livelihood of the surrounding people as a source of water for irrigation and grazing. Therefore, it is important to understand the mechanism of the fluctuations of glaciers.
Albedo is focused on as a cause of glacier melting, since surface albedo controls incoming shortwave radiation which is one of the main factors of absorbed heat for glacier ice melt. In this study, we will investigate the impact of albedo on glacier melting in addition to temperature and precipitation.
Data and Method
We used spatially and temporally continuous reanalysis products (ERA5 Land) to investigate the 2000-2020 change in precipitation and temperature. We also calculated the albedo using satellite images (Landsat 5,7,8) [1].
Surface level change in this study region was extracted from Huggonet et al., (2021), which was based on ASTER-DEM covering the entire world [2].
Result
Surface lowering rates have a decreasing trend in the study area between 2000 and 2020. Annual precipitation shows a significant increasing trend, while annual temperature shows no significant trend, on a five-year average. Then, the increasing trend of snowfall might contribute to the declining trend of surface lowering rate. However, even if all precipitation contributes to glacier accumulation, the decline of the surface lowering rate cannot be quantitatively explained. We have to consider about process of decrease in ablation as another process of the declining trend of surface lowering rate. Glacier melting would be suppressed due to higher albedo caused by frequent snow cover. We will show the detail of the analysis on albedo in the presentation.
References
[1] Liang S, 2001: Narrowband to broadband conversions of land surface albedo I algorithms. Remote Sensing of Environment,76(2000), 213–238.
[2] Hugonnet, R., et al, 2021: Accelerated global glacier mass loss in the early twenty-first century. Nature, 592(7856), 726- 731.
Mountain glaciers have been shrinking in recent years due to global warming in the world. In the Altai Mountains, glacial meltwater is essential for the livelihood of the surrounding people as a source of water for irrigation and grazing. Therefore, it is important to understand the mechanism of the fluctuations of glaciers.
Albedo is focused on as a cause of glacier melting, since surface albedo controls incoming shortwave radiation which is one of the main factors of absorbed heat for glacier ice melt. In this study, we will investigate the impact of albedo on glacier melting in addition to temperature and precipitation.
Data and Method
We used spatially and temporally continuous reanalysis products (ERA5 Land) to investigate the 2000-2020 change in precipitation and temperature. We also calculated the albedo using satellite images (Landsat 5,7,8) [1].
Surface level change in this study region was extracted from Huggonet et al., (2021), which was based on ASTER-DEM covering the entire world [2].
Result
Surface lowering rates have a decreasing trend in the study area between 2000 and 2020. Annual precipitation shows a significant increasing trend, while annual temperature shows no significant trend, on a five-year average. Then, the increasing trend of snowfall might contribute to the declining trend of surface lowering rate. However, even if all precipitation contributes to glacier accumulation, the decline of the surface lowering rate cannot be quantitatively explained. We have to consider about process of decrease in ablation as another process of the declining trend of surface lowering rate. Glacier melting would be suppressed due to higher albedo caused by frequent snow cover. We will show the detail of the analysis on albedo in the presentation.
References
[1] Liang S, 2001: Narrowband to broadband conversions of land surface albedo I algorithms. Remote Sensing of Environment,76(2000), 213–238.
[2] Hugonnet, R., et al, 2021: Accelerated global glacier mass loss in the early twenty-first century. Nature, 592(7856), 726- 731.