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Microstructure turbulence and diffusivity parameterization in the tropical and subtropical Atlantic, Pacific and Indian Oceans during the Malaspina 2010 expedition

Microstructure turbulence and diffusivity parameterization in the tropical and subtropical Atlantic, Pacific and Indian Oceans during the Malaspina 2010 expedition
Microstructure turbulence and diffusivity parameterization in the tropical and subtropical Atlantic, Pacific and Indian Oceans during the Malaspina 2010 expedition
Measurements of microstructure turbulence were carried out, in the upper 300m, in the tropical and subtropical Atlantic and Pacific oceans during the Malaspina 2010 expedition, by using a microstructure turbulence (MSS) profiler. Diapycnal diffusivity (Kρ) was estimated from dissipation rates of turbulent kinetic energy (ε) measured by the MSS profiler, and also from hydrographic and meteorological data by using the K-profile parameterization (KPP). In the mixing layer, averaged Kρ (169×10-4m2s-1) and ε(16.8×10-8Wkg-1) were three and one orders of magnitude higher, respectively, compared to the ocean interior (0.59×10-4m2s-1 and 1.0×10-8Wkg-1). In general, the KPP showed a good agreement with diffusivity estimates derived from microstructure observations, both in the mixing layer and in the ocean interior. The KPP also reproduced the main regional patterns observed in the ocean interior. The analysis of turbulence generation mechanisms below the mixing layer showed that shear-induced mixing was more important in those regions influenced by the equatorial undercurrent, where averaged diffusivity was 2.27-3.62×10-4m2s-1. Favorable conditions for salt fingers formation were more frequently observed in the Atlantic, where, as a consequence of this process, diffusivity could increase up to 20%. This result could have important implications for the transport of heat and dissolved substances in these regions.
Diffusivity, K-profile parameterization, Microstructure turbulence, Salt fingers, Tropical and subtropical oceans
0967-0637
15-30
Fernández-Castro, B.
8017e93c-d5ee-4bba-b443-9c72ca512d61
Mouriño-Carballido, B.
c1dbf004-40db-4dbb-ac0c-2fe2c96d40b3
Benítez-Barrios, V. M.
eeccb60b-d621-42b6-990e-7330f934a088
Chouciño, P.
b0ebda43-f5f6-4c1a-a710-520be10023cd
Fraile-Nuez, E.
43c344c4-6f7c-4444-bc4a-fe4cf850e338
Graña, R.
1bfbf101-18c1-49e7-a08d-5e3e3d4299aa
Piedeleu, M.
aa71fbc2-f2a3-496f-b49d-faeeafc2e2a0
Rodríguez-Santana, A.
f10cbef7-c115-47b7-894f-7e86cbe3e2b7
Fernández-Castro, B.
8017e93c-d5ee-4bba-b443-9c72ca512d61
Mouriño-Carballido, B.
c1dbf004-40db-4dbb-ac0c-2fe2c96d40b3
Benítez-Barrios, V. M.
eeccb60b-d621-42b6-990e-7330f934a088
Chouciño, P.
b0ebda43-f5f6-4c1a-a710-520be10023cd
Fraile-Nuez, E.
43c344c4-6f7c-4444-bc4a-fe4cf850e338
Graña, R.
1bfbf101-18c1-49e7-a08d-5e3e3d4299aa
Piedeleu, M.
aa71fbc2-f2a3-496f-b49d-faeeafc2e2a0
Rodríguez-Santana, A.
f10cbef7-c115-47b7-894f-7e86cbe3e2b7

Fernández-Castro, B., Mouriño-Carballido, B., Benítez-Barrios, V. M., Chouciño, P., Fraile-Nuez, E., Graña, R., Piedeleu, M. and Rodríguez-Santana, A. (2014) Microstructure turbulence and diffusivity parameterization in the tropical and subtropical Atlantic, Pacific and Indian Oceans during the Malaspina 2010 expedition. Deep-Sea Research Part I: Oceanographic Research Papers, 94, 15-30. (doi:10.1016/j.dsr.2014.08.006).

Record type: Article

Abstract

Measurements of microstructure turbulence were carried out, in the upper 300m, in the tropical and subtropical Atlantic and Pacific oceans during the Malaspina 2010 expedition, by using a microstructure turbulence (MSS) profiler. Diapycnal diffusivity (Kρ) was estimated from dissipation rates of turbulent kinetic energy (ε) measured by the MSS profiler, and also from hydrographic and meteorological data by using the K-profile parameterization (KPP). In the mixing layer, averaged Kρ (169×10-4m2s-1) and ε(16.8×10-8Wkg-1) were three and one orders of magnitude higher, respectively, compared to the ocean interior (0.59×10-4m2s-1 and 1.0×10-8Wkg-1). In general, the KPP showed a good agreement with diffusivity estimates derived from microstructure observations, both in the mixing layer and in the ocean interior. The KPP also reproduced the main regional patterns observed in the ocean interior. The analysis of turbulence generation mechanisms below the mixing layer showed that shear-induced mixing was more important in those regions influenced by the equatorial undercurrent, where averaged diffusivity was 2.27-3.62×10-4m2s-1. Favorable conditions for salt fingers formation were more frequently observed in the Atlantic, where, as a consequence of this process, diffusivity could increase up to 20%. This result could have important implications for the transport of heat and dissolved substances in these regions.

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More information

Published date: 1 December 2014
Keywords: Diffusivity, K-profile parameterization, Microstructure turbulence, Salt fingers, Tropical and subtropical oceans

Identifiers

Local EPrints ID: 453582
URI: http://eprints.soton.ac.uk/id/eprint/453582
ISSN: 0967-0637
PURE UUID: 30b3f571-149a-4fbc-a402-c9b977fcd292
ORCID for B. Fernández-Castro: ORCID iD orcid.org/0000-0001-7797-854X

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Date deposited: 20 Jan 2022 17:31
Last modified: 21 Jan 2022 02:54

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Contributors

Author: B. Mouriño-Carballido
Author: V. M. Benítez-Barrios
Author: P. Chouciño
Author: E. Fraile-Nuez
Author: R. Graña
Author: M. Piedeleu
Author: A. Rodríguez-Santana

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