C042-07
Ice flow velocity and elevation change measurement Shirase Glacier and Totten Glacier using remote sensing data

Friday, 11 December 2020: 20:54
Virtual
Shotaro Ohkawa1, Koichiro Doi2, Kazuki Nakamura3 and Hiroto Nagai1, (1)Waseda University, Tokyo, Japan, (2)NIPR National Institute of Polar Research, Tokyo, Japan, (3)Nihon University, Tokyo, Japan
Recorded Presentation
Abstract:
The purpose of this study is to develop a higher spatial-resolution and optimized method to measure flow dynamics and ice elevation changes based on remote sensing techniques.

This study focuses on two glaciers, Totten Glacier and Shirase Glacier both in East Antarctica. A previous study found that Totten Glacier had been melted rapidly in two decades. On the other hand, the surrounding accumulation area for Shirase Glacier increased in its mass per unit area, observed by GRACE satellite gravimetry. Shirase Glacier is also known for one of the fastest ice streams in Antarctica.

In this study, ice flow velocities on Totten Glacier and Shirase Glacier were estimated an offset tracking method applied to Synthetic Aperture Radar (SAR) images using Sentinel-1 data and the Phased Array L-band SAR-2 (PALSAR-2) onboard Advanced Land Observing Satellite-2 (ALOS-2) of ScanSAR mode data. Sentinel-1 data acquired from 2018 to 2020, PALSAR-2 data acquired in 2017.

Ice sheets and glaciers elevation change were measured by satellite-based LiDAR altimetry. This study calculated the difference between several cycles of ICESat-2 elevation data and TanDEM-X elevation data as a standard surface for estimating ice elevation change of Shirase Glacier and Totten Glacier. On the same tracks of ICESat-2, repeat observations have distant footprints, therefore acquired data are difficult to be compared directly.

As a result, the flowing rate of Shirase Glacier was at steady rates near the grounding line of the glacier from 1996 to 2019 which was suggested the annual flow velocity did not show significant changes that period. Those of Totten Glacier from grounding line to carving front using PALSAR-2 data were only observable near the carving front using Sentinel-1.

In the next step, we will analyze the elevation change using ICESat-2 data collected by 2018 to 2019. We also try to perform offset tracking of Totten Glacier using Sentinel-1 for acquired flow velocity from the grounding line to the carving front.

This study was partially supported by JSPS KAKENHI Grant No. 17H06321.

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