FINE-STRUCTURE, MICROSTRUCTURE, AND VERTICAL MIXING PROCESSES IN THE UPPER OCEAN IN THE WESTERN WEDDELL SEA

Citation
R. Robertson et al., FINE-STRUCTURE, MICROSTRUCTURE, AND VERTICAL MIXING PROCESSES IN THE UPPER OCEAN IN THE WESTERN WEDDELL SEA, J GEO RES-O, 100(C9), 1995, pp. 18517-18535
Citations number
49
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oceanografhy
Journal title
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
ISSN journal
2169-9275 → ACNP
Volume
100
Issue
C9
Year of publication
1995
Pages
18517 - 18535
Database
ISI
SICI code
2169-9275(1995)100:C9<18517:FMAVMP>2.0.ZU;2-3
Abstract
The upward flux of heat from the subsurface core of Warm Deep Water (W DW) to the perennially ice-covered sea surface over the continental sl ope in the western Weddell Sea is estimated using data obtained during February-June 1992 from a drifting ice station. Through the permanent pycnocline the diapycnal heat flux is estimated to be about 3 W m(-2) , predominantly because of double-diffusive convection. There is no ev idence that shear-driven mixing is important in the pycnocline. The es timated mean rate of heat transfer from the mixed layer to the ice is 1.7 W m(-2), although peak heat fluxes of up to 15 W m(-2) are found d uring storms. It is hypothesized that isopycnal mixing along sloping i ntrusions also contributes to the loss of heat from the WDW in this re gion; however, we are unable to quantify the fluxes associated with th is process. Intrusions occur intermittently throughout this experiment but are most commonly found near the boundary of the warm-core curren t and the shelf-modified water to the east. These heat fluxes are sign ificantly lower than the basin-averaged value of 19 W m(-2) (Fahrbach et al., 1994) that is required to balance the heat budget of the Wedde ll Gyre. Other studies suggest that shelf processes to the west of the ice station drift track and more energetic double-diffusive convectio n in the midgyre to the east could account for the difference between our flux estimates for this region and those based on the basin-scale heat budget.