Abstract

Impacts of bottom corrugations on a dense Antarctic outflow: The NW Ross Sea

Robin Muench
Earth & Space Research, 2101 Fourth Ave., Suite 1310, Seattle, WA 98121, USA

Anna Wåhlin
Göteborg University, Sweden

Tamay Özgömen
RSMAS, University of Miami, FL, USA

Bob Hallberg
NOAA/GFDL, Princeton, NJ, USA

Laurie Padman
Earth & Space Research, 3350 SW Cascade Ave., Corvallis, OR 97333-1536, USA



Prominent seabed corrugations, axially oriented roughly down-slope, are present along the Antarctic continental slope.  We use analytical and numerical model results to assess the potential impact of these corrugations on outflows of dense shelf water that contribute to Antarctic Bottom Water. Down-slope flow increases with increasing corrugation height and varies with along-slope wavelength. For parameters appropriate to the northwest Ross Sea, where heights and wavelengths are ~10-20 m and ~1.5 km, respectively, we estimate that the corrugations increase the down-slope transport of dense water, relative to the smooth bottom case, by ~13%. Corrugations enhance entrainment and reduce along-slope speed of the dense outflow.  Larger amplitude corrugations (~100 m) observed in other regions may impact outflows elsewhere around the poorly mapped Antarctic continental margin. Our results emphasize the need to consider small-scale local topography when modeling dense outflows.