The Relationship between Water Mass Formation and the Surface Buoyancy Flux, with Application to Phillips’ Red Sea Model

Abstract A new formulation is proposed for the evaluation of the dianeutral transport in the ocean. The method represents an extension of the classical diagnostic approach for estimating the water-mass formation from the buoyancy balance. The inclusion of internal sources such as the penetrative solar shortwave radiation (i.e., depth-dependent heat transfer) in the estimate of surface buoyancy fluxes has a significant impact in several oceanic regions, and the former simplified formulation can lead to a 100% error in the estimate of water-mass formation due to surface buoyancy fluxes. Furthermore, internal mixing can also be overestimated in inversions of in situ data when the shortwave radiation is not allowed to be penetrative. The method examines the evolution equation of neutral density via the tendencies of potential temperature and salinity. The neutral density framework does not require the choice of a reference pressure and thus, unlike previous approaches that consider potential density, it is well suited for examining the whole open-ocean water column. The methodology is easy to implement, particularly for ocean numerical models. The authors present here its application to a long simulation made with an ice–ocean global model, which allowed the method to be validated.

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Water Mass Formation, Overturning Circulation, and the Exchange of the Red Sea with the Adjacent Basins

The Red Sea - Springer Earth System Sciences ◽

10.1007/978-3-662-45201-1_20 ◽

2015 ◽

pp. 343-353 ◽

Cited By ~ 12

Author(s):

Sarantis Sofianos ◽

William E. Johns

Keyword(s):

Red Sea ◽

Water Mass ◽

Overturning Circulation ◽

Water Mass Formation ◽

Mass Formation

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Eddy-Driven Exchange between the Open Ocean and a Sub–Ice Shelf Cavity

Journal of Physical Oceanography ◽

10.1175/jpo-d-13-0137.1 ◽

2013 ◽

Vol 43 (11) ◽

pp. 2372-2387 ◽

Cited By ~ 24

Author(s):

Marius Årthun ◽

Paul R. Holland ◽

Keith W. Nicholls ◽

Daniel L. Feltham

Keyword(s):

Water Mass ◽

High Salinity ◽

Open Ocean ◽

Weddell Sea ◽

Buoyancy Flux ◽

Ice Shelf ◽

Ice Production ◽

Surface Buoyancy ◽

Frontal Instability ◽

Surface Buoyancy Flux

Abstract The exchange between the open ocean and sub–ice shelf cavities is important to both water mass transformations and ice shelf melting. Here, the authors use a high-resolution (500 m) numerical model to investigate to which degree eddies produced by frontal instability at the edge of a polynya are capable of transporting dense high-salinity shelf water (HSSW) underneath an ice shelf. The applied surface buoyancy flux and ice shelf geometry is based on Ronne Ice Shelf in the southern Weddell Sea, an area of intense wintertime sea ice production where a flow of HSSW into the cavity has been observed. Results show that eddies are able to enter the cavity at the southwestern corner of the polynya where an anticyclonic rim current intersects the ice shelf front. The size and time scale of simulated eddies are in agreement with observations close to the Ronne Ice Front. The properties and strength of the inflow are sensitive to the prescribed total ice production, flushing the ice shelf cavity at a rate of 0.2–0.4 × 106 m3 s−1 depending on polynya size and magnitude of surface buoyancy flux. Eddy-driven HSSW transport into the cavity is reduced by about 50% if the model grid resolution is decreased to 2–5 km and eddies are not properly resolved.

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