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| Titel |
Basal melt, seasonal water mass transformation, ocean current variability, and deep convection processes along the Amery Ice Shelf calving front, East Antarctica |
| VerfasserIn |
Laura Herraiz Borreguero, John A. Church, Ian Alison, Beatriz Peña Molino, Richard Coleman, Mathias Tomczak, Mike Craven |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147734
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| Publikation (Nr.) |
 EGU/EGU2017-11938.pdf |
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| Zusammenfassung |
| Despite the Amery Ice Shelf (AIS) being the third largest ice shelf in Antarctica, the
seasonal variability of the physical processes involved in the AIS-ocean interaction
remains undocumented and a robust observational, oceanographic-based basal melt
rate estimate has been lacking. Here we use year-long time series of water column
temperature, salinity, and horizontal velocities measured along the ice shelf front
from 2001 to 2002. Our results show strong zonal variations in the distribution of
water masses along the ice shelf front: modified Circumpolar Deep Water (mCDW)
arrives in the east, while in the west, Ice Shelf Water (ISW) and Dense Shelf Water
(DSW) formed in the Mackenzie polynya dominate the water column. Baroclinic
eddies, formed during winter deep convection (down to 1100 m), drive the inflow of
DSW into the ice shelf cavity. Our net basal melt rate estimate is 57.4±25.3 Gt
yr?1 (1±0.4 m yr?1), larger than previous modeling-based and glaciological-based
estimates, and results from the inflow of DSW (0.52±0.38 Sv; 1 Sv=106 m3 s?1)
and mCDW (0.22±0.06 Sv) into the cavity. Our results highlight the role of the
Mackenzie polynya in the seasonal exchange of water masses across the ice shelf
front, and the role of the ISW in controlling the formation rate and thermohaline
properties of DSW. These two processes directly impact on the ice shelf mass balance,
and on the contribution of DSW/ISW to the formation of Antarctic Bottom Water. |
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