10:00 AM - 10:15 AM
[STT36-05] Short-term glacier velocity changes in the Southern Patagonian Ice Field detected by the Sentinel-1 satellite
Keywords:The Southern Patagonian Ice Field, Flow rate
The glaciers of the Southern Patagonian Ice Field are the second largest group of glaciers
in the Southern Hemisphere after Antarctica. Like the glaciers and ice sheet in Northern
Hemisphere, they are retreating and losing their mass. Although the flow rate of glaciers in
the Southern Patagonian Ice Field is known to change on a semi-annual to multi-year time-
scale, their changes in flow rate within a year are uncertain. In order to investigate the
detailed changes in the flow velocity, we obtained radar images acquired by the Sentinel-
1B satellite with a recurrent period of 12 days between 2019 and 2020, and estimated the
flow velocity at the relatively larger six glaciers using the pixel offset method on the
assumption of parallel flow approximation. Of the six glaciers (Occidental Glacier, Pio XI
Glacier, Asia Glacier, Tyndall Glacier, Viedma Glacier, O'Higgins Glacier), four (Pio XI
Glacier, Asia Glacier, Viedma Glacier, O'Higgins Glacier) exhibit winter speed-up signals
(Abe and Furuya, 2015), accelerating in winter and decelerating in summer. Pio XI Glacier,
Asia Glacier, and Viedma Glacier showed significant changes in their downstream areas
and accelerated by about 450%, 20%, and 30%, respectively, in winter. O'Higgins Glacier
showed significant changes in the upstream, accelerating by 30% in winter. However,
unlike the winter speed-up glaciers reported by Abe and Furuya (2015), the four glaciers
except Pio XI glacier have not been known as surge-type glaciers. Moreover, it is not clear
if any portion of those glaciers indicate so-called spring/summer speed-up signals like a
number of mountain glaciers in Northern Hemisphere. We will extend the analysis period to
confirm if the inferred short-term velocity changes are persistent every year.
in the Southern Hemisphere after Antarctica. Like the glaciers and ice sheet in Northern
Hemisphere, they are retreating and losing their mass. Although the flow rate of glaciers in
the Southern Patagonian Ice Field is known to change on a semi-annual to multi-year time-
scale, their changes in flow rate within a year are uncertain. In order to investigate the
detailed changes in the flow velocity, we obtained radar images acquired by the Sentinel-
1B satellite with a recurrent period of 12 days between 2019 and 2020, and estimated the
flow velocity at the relatively larger six glaciers using the pixel offset method on the
assumption of parallel flow approximation. Of the six glaciers (Occidental Glacier, Pio XI
Glacier, Asia Glacier, Tyndall Glacier, Viedma Glacier, O'Higgins Glacier), four (Pio XI
Glacier, Asia Glacier, Viedma Glacier, O'Higgins Glacier) exhibit winter speed-up signals
(Abe and Furuya, 2015), accelerating in winter and decelerating in summer. Pio XI Glacier,
Asia Glacier, and Viedma Glacier showed significant changes in their downstream areas
and accelerated by about 450%, 20%, and 30%, respectively, in winter. O'Higgins Glacier
showed significant changes in the upstream, accelerating by 30% in winter. However,
unlike the winter speed-up glaciers reported by Abe and Furuya (2015), the four glaciers
except Pio XI glacier have not been known as surge-type glaciers. Moreover, it is not clear
if any portion of those glaciers indicate so-called spring/summer speed-up signals like a
number of mountain glaciers in Northern Hemisphere. We will extend the analysis period to
confirm if the inferred short-term velocity changes are persistent every year.