Accession Number : ADA331708

Title :   Radiating Instability of Nonzonal Ocean Currents

Descriptive Note : Doctoral thesis

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s) : Kamenkovich, Igor V.

PDF Url : ADA331708

Report Date : FEB 1997

Pagination or Media Count : 199

Abstract : This thesis addresses the question of how a highly energetic eddy field could be generated in the interior of the ocean away from the swift boundary currents. The energy radiation due to the temporal growth of non-trapped (radiating) disturbances in such a boundary current is thought to be one of the main sources for the described variability. The problem of stability of an energetic current, such as the Gulf Stream, is formulated. The study then focuses on the ability of the current to support radiating instabilities capable of significant penetration into the far-field and their development with time. The conventional model of the Gulf Stream as a zonal current is extended to allow the jet axis to make an angle to a latitude circle. The linear stability of such a nonzonal flow, uniform in the along-jet direction on a beta-plane, is first studied. The stability computations are performed for piece-wise constant and continuous velocity profiles. New stability properties of nonzonal jets are discussed. In particular, the destabilizing effect of the meridional tilt of the jet axis is demonstrated. The radiating properties of nonzonal currents are found to be very different from those of zonal currents. In particular, purely zonal flows do not support radiating instabilities, whereas flows with a meridional component are capable of radiating long and slowly growing waves. The nonlinear terms are then included in the consideration and the effects of the nonlinear interactions on the radiating properties of the solution are studied in detail.

Descriptors :   *OCEAN CURRENTS, RADIATION, STABILITY, INTERACTIONS, THESES, KINETIC ENERGY, PERTURBATIONS, GULF STREAM.

Subject Categories : Physical and Dynamic Oceanography
      Statistics and Probability

Distribution Statement : APPROVED FOR PUBLIC RELEASE