Upper Ocean Variability in West
Antarctic Peninsula Continental
Shelf Waters as Measured Using Instrumented Seals
Daniel P. Costa1, John M. Klinck2, Eileen
E. Hofmann2, Michael S. Dinniman2, and Jennifer M. Burns3
1Department of Ecology and Evolutionary Biology
100 Shaffer Rd
University of California, Santa Cruz
Santa Cruz, CA 95060
2Center for Coastal Physical Oceanography
Old Dominion University
Norfolk, VA 23529
3Department of Biological Sciences, EBL 123
University of Alaska Anchorage
3211 Providence Dr.
Anchorage, AK 99508
Abstract
Temperature profile data for the
western Antarctic Peninsula (WAP) continental shelf waters, collected from
freely ranging instrumented crabeater seals (Lobodon carcinophagus),
were used to demonstrate that
these platforms can be used to supplement traditional oceanographic sampling
methods. The seal-derived profiles were
combined with temperature profiles obtained from ship-based CTD measurements
and from a numerical circulation model developed for the WAP to describe
changes in temperature structure, heat content, and heat flux in the upper
ocean waters of the WAP continental shelf.
We provide the first description of the seasonal cycle of erosion and
development of the Antarctic Surface Water (AASW) and Winter Water (WW) layers
for the WAP continental shelf. Further the seal-derived data documented the shelf-wide presence
of modified Circumpolar Deep Water (CDW) that is found below 150-200 m on the
WAP continental shelf. The heat content
of the upper 200 m calculated from the seal-derived temperature profiles ranged
between 1000 and 1500 J m-3; similar estimates were obtained from
the simulated temperature distributions and hydrographic measurements. Seal-derived measurements provide
broader space and time resolution than could be obtained using any other
currently available oceanographic sampling method.
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