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Diapycnal mixing in the Banda Sea: Results of the first microstructure measurements in the Indonesian Throughflow
Author(s) -
Alford Matthew H.,
Gregg Michael C.,
Ilyas Muhammed
Publication year - 1999
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 - 10.1029/1999gl002337
Subject(s) - throughflow , barotropic fluid , geology , baroclinity , thermal diffusivity , mixing (physics) , oceanography , dissipation , climatology , physics , thermodynamics , quantum mechanics , soil science
Models involving basin‐averaged T/S properties [ Ffield and Gordon , 1992; Hautala et al. , 1996] and barotropic/baroclinic tidal energy conversion [ Sjöberg and Stigebrandt , 1992] suggest that the Indonesian archipelago is a site of active mixing. This paper describes the first microstructure measurements made in the region. Aboard the R/V Baruna Jaya IV, we repeated 18 km legs centered on (6.5°S, 128°E), in the central Banda Sea, for two weeks during Oct/Nov 1998. With the Modular Microstructure Profiler, we gathered 519 profiles of potential temperature, salinity, potential density, pressure and kinetic energy dissipation rate. The cruise‐mean diapycnal diffusivity from 20–300 m isK ρ ¯ = ( 9.2 ± 0.55 ) × 10 −6 m 2 s −1 , similar to “open ocean” [ Garrett and Munk , 1975] values ( K ρ = 5.1 × 10 −6 m²s −1 ), and an order of magnitude below basin‐ and time‐averaged values obtained from the Ffield and Gordon [1992] and Hautala et al. [1996] models ( K ρ ≥ 1 × 10 −4 m²s −1 ). Sea‐surface temperature displays some evidence of a fortnightly modulation, interpreted by Ffield and Gordon [1996] as evidence for tidal mixing, but is uncorrelated with the dissipation rate just below the mixed layer.