5:15 PM - 6:45 PM
[ACC26-P02] Estimation of Glacier Terminus Mass Loss Using Satellite Data
In recent years, the number and surface area of glacial lakes in the Himalayas have been rapidly increasing, prompting numerous studies utilizing satellite data to assess these changes. While research has progressed in determining mass loss due to surface melting and flow dynamics in the ablation zones of glaciers, there has been limited quantification of mass loss at glacier termini. Understanding terminus mass loss is crucial, as it often constitutes a significant portion of total glacier mass loss and directly contributes to lake expansion, thereby increasing the risk of glacial lake outburst floods (GLOFs).
This study focuses on the terminus of the Trakarding Glacier in the Nepalese Himalayas, where terminus mass loss has been quantified from 1989 to 2015. Therefore, the objective of this study is to calculate the terminus mass loss from 2016 to 2023. Initially, annual Sentinel-2 satellite images from 2016 onwards were obtained to confirm the terminus position each year. Additionally, data on flow velocity and ice thickness for 2017-2018 were acquired from Millan et al. (2022) and assumed constant over time. These datasets were used to calculate both terminus retreat-induced mass loss and mass loss due to flow dynamics, thereby estimating the total terminus mass loss.
Retreat-induced mass loss refers to the volume of the retreated area at the terminus, while mass loss due to flow represents the volume of the glacier passing through the terminus cross-section per unit time. Millan et al. (2022) estimated flow velocity using image pairs from Landsat 8, Sentinel-2, and Sentinel-1, totaling approximately 135,000, 670,000, and 6,684 pairs, respectively. Ice thickness was derived using an assumed relationship based on the movement and gradient of ice surface obtained from satellite data, assuming simple shear deformation.
The analysis revealed an increasing trend in terminus mass loss since 2016, with most of the loss attributed to retreat-induced mass loss. Future efforts aim to derive annual flow velocities from satellite images and correct ice thickness data using bathymetric data to obtain more accurate terminus mass loss estimates.
This study focuses on the terminus of the Trakarding Glacier in the Nepalese Himalayas, where terminus mass loss has been quantified from 1989 to 2015. Therefore, the objective of this study is to calculate the terminus mass loss from 2016 to 2023. Initially, annual Sentinel-2 satellite images from 2016 onwards were obtained to confirm the terminus position each year. Additionally, data on flow velocity and ice thickness for 2017-2018 were acquired from Millan et al. (2022) and assumed constant over time. These datasets were used to calculate both terminus retreat-induced mass loss and mass loss due to flow dynamics, thereby estimating the total terminus mass loss.
Retreat-induced mass loss refers to the volume of the retreated area at the terminus, while mass loss due to flow represents the volume of the glacier passing through the terminus cross-section per unit time. Millan et al. (2022) estimated flow velocity using image pairs from Landsat 8, Sentinel-2, and Sentinel-1, totaling approximately 135,000, 670,000, and 6,684 pairs, respectively. Ice thickness was derived using an assumed relationship based on the movement and gradient of ice surface obtained from satellite data, assuming simple shear deformation.
The analysis revealed an increasing trend in terminus mass loss since 2016, with most of the loss attributed to retreat-induced mass loss. Future efforts aim to derive annual flow velocities from satellite images and correct ice thickness data using bathymetric data to obtain more accurate terminus mass loss estimates.