Dense water formation around islands
Spall, Michael A.
MetadataShow full item record
Basic constraints on the dense water formation rate and circulation resulting from cooling around an island are discussed. The domain under consideration consists of an island surrounded by a shelf, a continental slope, and a stratified ocean. Atmospheric cooling over the shelf forms a dense water that penetrates down the sloping bottom into the stratified basin. Strong azimuthal flows are generated over the sloping bottom as a result of thermal wind. Thermally direct and indirect mean overturning cells are also forced over the slope as a result of bands of convergent and divergent Reynolds stresses associated with the jets. The Coriolis force associated with the net mass flux into the downwelling region over the slope is balanced by these nonlinear terms, giving rise to a fundamentally different momentum budget than arises in semienclosed marginal seas subject to cooling. A similar momentum balance is found for cases with canyons and ridges around the island provided that the terms are considered in a coordinate system that follows the topography. Both eddy fluxes and the mean overturning cells are important for the radial heat flux, although the eddy fluxes typically dominate. The properties of the dense water formed over the shelf (temperature, diapycnal mass flux) are predicted well by application of baroclinic instability theory and simple heat and mass budgets. It is shown that each of these quantities depends only on a nondimensional number derived from environmental parameters such as the shelf depth, Coriolis parameter, offshore temperature field, and atmospheric forcing.
Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 2507–2519, doi:10.1002/jgrc.20185.
Showing items related by title, author, creator and subject.
Hein, Christopher J.; FitzGerald, Duncan M.; Carruthers, Emily A.; Stone, Byron D.; Barnhardt, Walter A.; Gontz, Allen M. (2012-02-24)Details of the internal architecture and local geochronology of Plum Island, the longest barrier in the Gulf of Maine, has refined our understanding of barrier island formation in paraglacial settings. Ground-penetrating ...
Inundation of a barrier island (Chandeleur Islands, Louisiana, USA) during a hurricane : observed water-level gradients and modeled seaward sand transport Sherwood, Christopher R.; Long, Joseph W.; Dickhudt, Patrick J.; Dalyander, P. Soupy; Thompson, David M.; Plant, Nathaniel G. (John Wiley & Sons, 2014-07-15)Large geomorphic changes to barrier islands may occur during inundation, when storm surge exceeds island elevation. Inundation occurs episodically and under energetic conditions that make quantitative observations difficult. ...
On the connection between dense water formation, overturning, and poleward heat transport in a convective basin Straneo, Fiamma (American Meteorological Society, 2006-09)An isopycnal, two-layer, idealized model for a convective basin is proposed, consisting of a convecting, interior region and a surrounding boundary current (buoyancy and wind-driven). Parameterized eddy fluxes govern the ...