Entrainment, detrainment, and large-scale horizontal gradients in oceanic deep convection
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Authors
Stone, Rebecca E.
Subjects
CONVECTION
OCEANS
GRADIENTS
ENTRAINMENT
SIMULATION
SPATIAL DISTRIBUTION
DENSITY
ENVIRONMENTS
MODELS
THEORY
INTENSITY
TURBULENCE
EDDIES(FLUID MECHANICS)
REGIONS
VARIATIONS
WINTER
SCALE
STRATIFICATION
INSTABILITY
HORIZONTAL ORIENTATION
OCEANS
GRADIENTS
ENTRAINMENT
SIMULATION
SPATIAL DISTRIBUTION
DENSITY
ENVIRONMENTS
MODELS
THEORY
INTENSITY
TURBULENCE
EDDIES(FLUID MECHANICS)
REGIONS
VARIATIONS
WINTER
SCALE
STRATIFICATION
INSTABILITY
HORIZONTAL ORIENTATION
Advisors
Guest, Peter S.
Harcourt, Ramsey R.
Maslowski, Wieslaw
Semtner, Albert J.
Garwood, Roland W., Jr.
Date of Issue
1999-06
Date
June 1999
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
The theory of oceanic convection and entrainment has been developed mainly in horizontally homogeneous regimes, yet large-scale spatial variability is known to control the sites and intensity of deep convection. Wintertime Greenland Sea conditions were selected to simulate convection and quantify the interplay between local forcing and large-scale gradients. Here circulation and preconditioning produce horizontal gradients in the stratification; some of the resulting stratification conducive to the formation of thermobaric convective instabilities. A large eddy simulation (LES) model modified to include large- scale horizontal density gradients was used to study the effects of the gradients on turbulence. Horizontal turbulent kinetic energy (IKE) and scalar variances increased compared to simulations with no large-scale gradient. The additional horizontal IKE is created at scales larger than the convective plume scale. A mean horizontal circulation develops in response to the large-scale overturning. The balance between convection and overturning increases stratification in the lower region of the mixed layer, and plumes may undergo slantwise convection.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Identifiers
NPS Report Number
Sponsors
Funding
Format
xvi, 123 p. ; 28 cm.
Citation
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.