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Carl Wunsch. Federiuk, Joyce Marie Woods Hole Oceanographic Institution. Joint Program in Oceanography Woods Hole Oceanographic Institution Massachusetts Institute of Technology. Department of Ocean Engineering 2010-04-07T13:37:35Z 2010-04-07T13:37:35Z 1988 http://hdl.handle.net/1721.1/53530 18613317 Thesis (M.S.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), February 1988. "October 1987." Includes bibliographical references (leaves 87-89). Thermohaline staircases consisting of a series of well mixed layers approximately 30 m thick are found at depths of 300-500 m in a region of the tropical North Atlantic spanning 48° to 58°W, 8° to 17° N. Density ratios ( ... ) with values near 1 indicate a double diffusive origin for the structure (Schmitt, 1981,1986). Determining the importance of double-diffusive mixing to the regional advection - diffusion balance is the subject of this study. Using hydrographic and current meter data collected in the C-SALT program of 1985 (Schmitt, 1987), we construct inverse models in both cartesian and density coordinates and seek bounds on the cross isopycnal mixing in the staircase region. In cartesian coordinates, the role of diffusion was not well resolved, probably due to inadequacy of the steady state model in the presence of eddies. By reformulating the problem in boxes bounded by isopycnals which more closely follow the layers, and solving directly for cross isopycnal fluxes of salt and heat, the resolution of the diffusivities was improved. Inversions were done on data from the spring and fall CTD surveys. The average salt diffusivity in the step region was estimated from the isopycnal inversions to be ks = (2.8 + 1.3)cm2 /s in spring and ks = (3.9 ± 2.2)cm2 /s in fall. by Joyce Marie Federiuk. M.S. 90 leaves eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Joint Program in Oceanography. Earth, Atmospheric, and Planetary Sciences. Woods Hole Oceanographic Institution. Determination of advection and diffusion in a thermohaline staircase region Thesis application/pdf Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="4428b52c-89a4-4037-8763-1c4f00e4e5e7"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Determination of advection and diffusion in a thermohaline staircase region</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>1988</PublicationDate> <Authors> <Author> <DisplayName>Federiuk, Joyce Marie</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Joint Program in Oceanography.</Keyword> <Keyword>Earth, Atmospheric, and Planetary Sciences.</Keyword> <Keyword>Woods Hole Oceanographic Institution.</Keyword> <Abstract>Thermohaline staircases consisting of a series of well mixed layers approximately 30 m thick are found at depths of 300-500 m in a region of the tropical North Atlantic spanning 48° to 58°W, 8° to 17° N. Density ratios ( ... ) with values near 1 indicate a double diffusive origin for the structure (Schmitt, 1981,1986). Determining the importance of double-diffusive mixing to the regional advection - diffusion balance is the subject of this study. Using hydrographic and current meter data collected in the C-SALT program of 1985 (Schmitt, 1987), we construct inverse models in both cartesian and density coordinates and seek bounds on the cross isopycnal mixing in the staircase region. In cartesian coordinates, the role of diffusion was not well resolved, probably due to inadequacy of the steady state model in the presence of eddies. By reformulating the problem in boxes bounded by isopycnals which more closely follow the layers, and solving directly for cross isopycnal fluxes of salt and heat, the resolution of the diffusivities was improved. Inversions were done on data from the spring and fall CTD surveys. The average salt diffusivity in the step region was estimated from the isopycnal inversions to be ks = (2.8 + 1.3)cm2 /s in spring and ks = (3.9 ± 2.2)cm2 /s in fall.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>