Tomographic Observations of Deep Convection and the Thermal Evolution of the Greenland Sea Gyre 1988-1989.

• Main Author: Pawlowicz, Ryszard A.
• Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
• Format: Text
• Language: English
• Published: 1994
• Subjects: Physical and Dynamic Oceanography; Snow; Ice and Permafrost; Meteorology; *OCEANOGRAPHIC DATA; *TOMOGRAPHY; *SEA ICE; *GREENLAND SEA; EXPERIMENTAL DATA; OCEAN CURRENTS; OCEAN SURFACE; COMPARISON; THESES; ICE FORMATION; SEASONAL VARIATIONS; SURFACE WATERS; CLIMATE; CONVECTION(HEAT TRANSFER); MIXED LAYER(MARINE); SALINITY; HEAT FLUX; SURFACE TEMPERATURE; UNDERWATER ACOUSTICS; STRATIFICATION; MARINE METEOROLOGY; WATER MASSES; DEEP WATER; OPEN WATER; ARCTIC REGIONS; 14; Arctic; Greenland; South Ice; Greenland Sea; Ice; permafrost; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA289104; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA289104

The Greenland Sea Gyre is studied using results from the 1988-89 Greenland Sea Tomography Experiment. Thermal evolution of the gyre center divides into three periods: a preconditioning phase, a deep mixing phase, and a restratification phase. During preconditioning, ice forms and rejects brine into the surface waters, enabling destabilization of the water column. The onset of the deep mixing phase occurs after ice formation in the gyre center stops, resulting in an area of open water where large heat fluxes can occur. In surrounding regions, including the odden region to the south, ice is still being formed, and the mixed layer does not deepen significantly. The effects of advection are deduced from heat and salt budgets, and appear to be important only during the restratification phase for intermediate depths, and only during the summer for the surface waters. Dynamical processes for bringing the Arctic Intermediate Water (AIW) to the surface in order to form deep water are not needed in this scenario, rather the surface waters are modified until they match the density of the AIW after which surface cooling drives convection. Also supported by grant N00014-87-K-0017. Prepared in cooperation wth Massachusetts Institute of Technology, Cambridge.