Mediterranean Overflow Water (MOW) Simulation Using a Coupled Multiple-Grid Mediterranean Sea/North Atlantic Ocean Model

A z-level, 4th-order-accurate ocean model is applied in six two-way-coupled grids spanning the Mediterranean Sea and North Atlantic Ocean (MEDiNA). Resolutions vary from 1/4 deg in central North Atlantic to 1/24 deg in Strait of Gibraltar region. This allows the MEDiNA model to efficiently resolve s...

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Bibliographic Details
Main Authors: Dietrich, David E., Tseng, Yu-Heng, Medina, Raul, Piacsek, Steve A., Liste, Maria, Olabarrieta, Maitane, Bowman, Malcolm J., Mehra, Avichal
Other Authors: NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
Format: Text
Language:English
Published: 2008
Subjects:
Physical and Dynamic Oceanography
*MEDITERRANEAN SEA
*NORTH ATLANTIC OCEAN
*OCEAN MODELS
*OCEAN CURRENTS
MIXING
GIBRALTAR STRAIT
SALINITY
ENTRAINMENT
DENSITY
REPRINTS
COUPLING(INTERACTION)
*MOW(MEDITERRANEAN OVERFLOW WATER)
MEDINA OCEAN MODEL
DOME(DYNAMICS OF OVERFLOW MIXING AND ENTRAINMENT)
COUPLED MODELS
DENSITY CURRENTS
PE0602435N
WU73-6631-C6-5
Medina
North Atlantic
Online Access:http://www.dtic.mil/docs/citations/ADA488862
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA488862
Description
Summary:A z-level, 4th-order-accurate ocean model is applied in six two-way-coupled grids spanning the Mediterranean Sea and North Atlantic Ocean (MEDiNA). Resolutions vary from 1/4 deg in central North Atlantic to 1/24 deg in Strait of Gibraltar region. This allows the MEDiNA model to efficiently resolve small features (e.g., Strait of Gibraltar) in a multibasin, multiscale model. Such small features affect all scales because of nonlinearity and low dissipation. The grid coupling using one coarse grid overlap is nearly seamless without intergrid sponge layers. No instant convective adjustment or other highly diffusive process is used. The deep water in the 1/8 deg Mediterranean Sea grid is formed by the resolved flows that emulate subgrid-scale processes directly. Downslope migration of Mediterranean Overflow Water (MOW) water involves dense water flowing away from the bottom laterally over bottom stairsteps in the z-level model, thus flowing over less dense underlying water. Without excessively water mass-diluting process, the advection dominates the downs lope migration of thin, dense MOW in the simulation. The model results show realistic MOW migration to the observed equilibrium depth, followed by lateral spreading near that depth. The results are also consistent with the climatology along 43 deg N, where the MOW hugs a steep shelfslope centered at 1 km depth and then spreads westward, with the salinity core (S > 35.7) reaching 18 deg W. This study clearly restores z-level models to a competitive status doing density current simulations. Published in Journal of Geophysical Research, v113 nC07027, 2008. The original document contains color images. All DTIC reproductions will be in black and white.

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