Oceanic erosion of a floating Antarctic glacier in the Amundsen Sea


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hhellmer [ at ] awi-bremerhaven.de

Abstract

A survey of the southern Amundsen and Bellingshausen seas in early 1994 included the first deepoceanographic measurements along the calving front of Pine Island Glacier, which drains~2x10^5 km^2 of the marine-based West Antarctic Ice Sheet. The measurements reveal a cycloniccirculation in Pine Island Bay and >1 degC Circumpolar Deep Water flowing beneath and rapidlymelting the floating base of this deep-rooted glacier. Dissolved oxygen measurements show asubsurface oxygenation of the water column resulting from air bubbles in the melting ice. Seawateroxygen isotope analyses imply average delta18O values of -29 permil for precipitation on thecatchment basin that subsequently melts at the glacier base. Application of a two-dimensionalthermohaline circulation model to the sub-ice shelf cavity supports average basal melt rates inexcess of 10 m/a calculated by two other methods. This melt rate is more than 5 times the averagereported for any Antarctic ice shelf, drives Circumploar Deep Water upwelling on the continentalshelf, and generates melt-laden outflows that are well above surface freezing temperature.



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Peer-reviewed
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Published
Eprint ID
1254
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Hellmer, H. , Jacobs, S. S. and Jenkins, A. (1998): Oceanic erosion of a floating Antarctic glacier in the Amundsen Sea , Ocean, Ice, and Atmosphere: Interactions at the Antarctic continental margin (S Jacobs, R Weiss, eds ) Antarctic Research Series, AGU, Washington DC, USA, 75 , pp. 319-339 .


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