Kinematics and energetics of the mesoscale mid-ocean circulation : MODE


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dc.contributor.author Richman, James G.
dc.coverage.spatial Hatteras Abyssal Plain
dc.date.accessioned 2006-12-01T16:57:02Z
dc.date.available 2006-12-01T16:57:02Z
dc.date.issued 1976-09
dc.identifier.uri http://hdl.handle.net/1912/1356
dc.description Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September, 1976 en
dc.description.abstract The temporal and spatial variability of low frequency moored temperature and velocity observations, obtained as part of the Mid-Ocean Dynamics Experiment (MODE), are analyzed to study the kinematics and energetics of mesoscale eddies in the ocean. The temporal variability of the low frequency motions is characterized by three regimes: very low frequencies with periods greater than 200 days, an eddy energy containing band of 80 to 120 day periods, and high frequencies wìth periods less than 30 days. At very low frequencies, the zonal kinetic energy exceeds the meridional at all depths. In the thermocline, the very low frequency zonal flow dominates the total kinetic energy. The greatest contribution to the kinetic and potential energy in the MODE region, except for the thermocline zonal flow, is from an eddy energy containing band of 80 to 120 day periods. Eddy scale kinetic energy spatial variations are confined to this band. At high frequencies, the kinetic and potential energy scale with frequency as ω-2.5 and with depth in the WKB sense. Energy at high frequencies is partitioned evenly between zonal kinetic, meridional kinetic and potential energy and is homogeneous over 100 km. Using the technique of empirical orthogonal expansion, the vertical structure of the energetically dominant eddies is described by a few modes. The displacement is dominated by a mode with a thermocline maximum and in phase displacements with depth, while the kinetic energy is dominated by an equivalent barotropic mode. A smaller portion of the kinetic and potential energy is associated with out of phase thermocline and deep water currents and displacements. The dynamics of the mesoscale eddies are very nonlinear. Using the vertical veering of the current at MODE Center, the estimated horizontal advection of heat contributes significantly to the low frequency thermal balance. The observed very low frequency anisotropic flow is consistent with the nonlinear eddy spindown models, dominated by cascades of vorticity and energy. At high frequencies, the spectral similarity is consistent with advected geostrophic turbulence. en
dc.description.sponsorship The National Science Foundation supported the work through grants GX29034 and IDO-75-03998 and a graduate fellowship. en
dc.format.extent 7112504 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher Massachusetts Institute of Technology and Woods Hole Oceanographic Institution en
dc.relation.ispartofseries WHOI Theses en
dc.subject Ocean currents en
dc.subject Ocean circulation en
dc.subject Ocean temperature en
dc.title Kinematics and energetics of the mesoscale mid-ocean circulation : MODE en
dc.type Thesis en
dc.identifier.doi 10.1575/1912/1356

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