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Extratropical sources of Equatorial Pacific upwelling in an OGCM
Author(s) -
Rodgers Keith B.,
Blanke Bruno,
Madec Gurvan,
Aumont Olivier,
Ciais Philippe,
Dutay JeanClaude
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl016003
Subject(s) - ocean gyre , advection , upwelling , oceanography , geology , extratropical cyclone , water mass , boundary current , equator , atlantic hurricane , climatology , ocean general circulation model , structural basin , oceanic basin , stratification (seeds) , downwelling , ocean current , latitude , subtropics , general circulation model , climate change , geomorphology , seed dormancy , biology , tropical cyclone , germination , geodesy , thermodynamics , physics , botany , dormancy , fishery
The extratropical sources of equatorial undercurrent (EUC) water have been identified for an ocean circulation model using Lagrangian trajectory analysis. It has been found that the EUC waters emenate from a wide range of latitudes in the Pacific basin, with its densest constituent watermass being Subantarctic Mode Water (SAMW) from 50°S. Further analysis of the basin‐scale circulation fields has revealed significant advective diapycnal mass fluxes associated with intergyre exchange. As a result of these diapycnal mass fluxes, the EUC transport as a function of density at 151°W (an Eulerian diagnostic) looks quite different from the original subduction rate as a function of density for the same collection of water particles. This implicates diapycnal vertical mixing as an important player in determining the preferred density horizon of maximum EUC transport along the equator. In summary, these results illustrate an important interdependence between advective and diapycnal mixing processes associated with basin‐scale inter‐gyre and inter‐basin exchange in determining the mean equatorial stratification and EUC structure.