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Advanced insights into sources of vertical velocity in the ocean
- Source :
- Ocean Dynamics, Ocean Dynamics, 2006, 56 (5-6), pp.513-524. ⟨10.1007/s10236-005-0050-1⟩
- Publication Year :
- 2006
- Publisher :
- Springer Science and Business Media LLC, 2006.
-
Abstract
- Estimating vertical velocity in the oceanic upper layers is a key issue for understanding ocean dynamics and the transport of biogeochemical elements. This paper aims to identify the physical sources of vertical velocity associated with sub-mesoscale dynamics (fronts, eddies) and mixed-layer depth (MLD) structures, using (a) an ocean adaptation of the generalized Q-vector form of the omega-equation deduced from a primitive equation system which takes into account the turbulent buoyancy and momentum fluxes and (b) an application of this diagnostic method for an ocean simulation of the Programme Ocean Multidisciplinaire Meso Echelle (POMME) field experiment in the North-Eastern Atlantic. The approach indicates that w-sources can play a significant role in the ocean dynamics and strongly depend on the dynamical structure (anticyclonic eddy, front, MLD, etc.). Our results stress the important contribution of the ageostrophic forcing, even under quasi-geostrophic conditions. The turbulent w-forcing was split into two components associated with the spatial variability of (a) the buoyancy and momentum (Ekman pumping) surface fluxes and (b) the MLD. Process (b) represents the trapping of the buoyancy and momentum surface energy into the MLD structure and is identified as an atmosphere/oceanic mixed-layer coupling. The momentum-trapping process is 10 to 100 times stronger than the Ekman pumping and is at least 1,000 times stronger than the buoyancy w-sources. When this decomposition is applied to a filamentary mixed-layer structure simulated during the POMME experiment, we find that the associated vertical velocity is created by trapping the surface wind-stress energy into this structure and not by Ekman pumping.
- Subjects :
- Physics
Momentum (technical analysis)
Buoyancy
010504 meteorology & atmospheric sciences
010505 oceanography
Turbulence
Front (oceanography)
Forcing (mathematics)
Geophysics
engineering.material
Oceanography
01 natural sciences
Physics::Geophysics
Physics::Fluid Dynamics
Ocean dynamics
Eddy
13. Climate action
Ekman transport
engineering
14. Life underwater
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Physics::Atmospheric and Oceanic Physics
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 16167228 and 16167341
- Volume :
- 56
- Database :
- OpenAIRE
- Journal :
- Ocean Dynamics
- Accession number :
- edsair.doi.dedup.....a41e9aecc5ce3982daa6363aabf9196d