Calving event size measurements and statistics of Eqip Sermia, Greenland, from terrestrial radar interferometry
Calving is a crucial process for the recently observed dynamic mass loss changes of the Greenland ice sheet. Despite its importance for global sea level change, major limitations in understanding the process of calving remain. This study presents high-resolution calving event data and statistics rec...
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Veröffentlicht in: | The cryosphere 2020-03, Vol.14 (3), p.1051-1066 |
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Zusammenfassung: | Calving is a crucial process for the recently observed
dynamic mass loss changes of the Greenland ice sheet. Despite its importance
for global sea level change, major limitations in understanding the process
of calving remain. This study presents high-resolution calving event data
and statistics recorded with a terrestrial radar interferometer at the front
of Eqip Sermia, a marine-terminating outlet glacier in Greenland. The
derived digital elevation models with a spatial resolution of several metres
recorded at 1 min intervals were processed to provide source areas and
volumes of 906 individual calving events during a 6 d period. The calving
front can be divided into sectors ending in shallow and deep water with
different calving statistics and styles. For the shallow sector,
characterized by an inclined and very high front, calving events are more
frequent and larger than for the vertical ice cliff of the deep sector. We
suggest that the calving volume deficiency of 90 % relative to the
estimated ice flux in our observations of the deep sector is removed by
oceanic melt, subaquatic calving, and small aerial calving events. Assuming a
similar ice thickness for both sectors implies that subaqueous mass loss
must be substantial for this sector with a contribution of up to 65 % to
the frontal mass loss. The size distribution of the shallow sector is
represented by a log-normal model, while for the deep sector the log-normal
and power-law model fit well, but none of them are significantly better.
Variations in calving activity and style between the sectors seem to be
controlled by the bed topography and the front geometry. Within the short
observation period no simple relationship between environmental forcings and
calving frequency or event volume could be detected. |
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ISSN: | 1994-0424 1994-0416 1994-0424 1994-0416 |
DOI: | 10.5194/tc-14-1051-2020 |