Accession Number : ADA624445


Title :   Coastal Trapped Waves, Alongshore Pressure Gradients, and the California Undercurrent


Descriptive Note : Journal article


Corporate Author : NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV


Personal Author(s) : Connolly, Thomas P ; Hickey, Barbara M ; Shulman, Igor ; Thomson, Richard E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a624445.pdf


Report Date : Jan 2014


Pagination or Media Count : 25


Abstract : The California Undercurrent (CUC), a poleward-flowing feature over the continental slope, is a key transport pathway along the west coast of North America and an important component of regional upwelling dynamics. This study examines the poleward undercurrent and alongshore pressure gradients in the northern California Current System (CCS), where local wind stress forcing is relatively weak. The dynamics of the undercurrent are compared in the primitive equation Navy Coastal Ocean Model and a linear coastal trapped wave model. Both models are validated using hydrographic data and current-meter observations in the core of the undercurrent in the northern CCS. In the linear model, variability in the predominantly equatorward wind stress along the U.S. West Coast produces episodic reversals to poleward flow over the northern CCS slope during summer. However, reproducing the persistence of the undercurrent during late summer requires additional incoming energy from sea level variability applied south of the region of the strongest wind forcing. The relative importance of the barotropic and baroclinic components of the modeled alongshore pressure gradient changes with latitude. In contrast to the southern and central portions of the CCS, the baroclinic component of the alongshore pressure gradient provides the primary poleward force at CUC depths over the northern CCS slope. At time scales from weeks to months, the alongshore pressure gradient force is primarily balanced by the Coriolis force associated with onshore flow.


Descriptors :   *OCEAN MODELS , CONTINENTAL SLOPES , CURRENTS , FLOW , MATHEMATICAL MODELS , PRESSURE GRADIENTS , UPWELLING , WIND STRESS


Subject Categories : Physical and Dynamic Oceanography


Distribution Statement : APPROVED FOR PUBLIC RELEASE