Coastal trapped waves, alongshore pressure gradients, and the California Undercurrent

View/ Open
Date
2014-01Author
Connolly, Thomas P.
Concept link
Hickey, Barbara M.
Concept link
Shulman, Igor
Concept link
Thomson, Richard E.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/6702As published
https://doi.org/10.1175/JPO-D-13-095.1DOI
10.1175/JPO-D-13-095.1Keyword
Geographic location/entity; Continental shelf/slope; Circulation/ Dynamics; Baroclinic flows; Coastal flows; Models and modeling; Model evaluation/performance; Variability; Intraseasonal variability; Seasonal variabilityAbstract
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.
Description
Author Posting. © American Meteorological Society, 2014. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 44 (2014): 319–342, doi:10.1175/JPO-D-13-095.1.
Collections
Suggested Citation
Journal of Physical Oceanography 44 (2014): 319–342Related items
Showing items related by title, author, creator and subject.
-
Air-sea CO2 fluxes and the controls on ocean surface pCO2 seasonal variability in the coastal and open-ocean southwestern Atlantic Ocean : a modeling study
Arruda, R.; Calil, Paulo H. R.; Bianchi, A. A.; Doney, Scott C.; Gruber, Nicolas; Lima, Ivan D.; Turi, G. (Copernicus Publications on behalf of the European Geosciences Union, 2015-10-12)We use an eddy-resolving, regional ocean biogeochemical model to investigate the main variables and processes responsible for the climatological spatio-temporal variability of pCO2 and the air-sea CO2 fluxes in the ... -
Trend and interannual variability in southeast Greenland Sea Ice : impacts on coastal Greenland climate variability
Moore, G. W. K.; Straneo, Fiamma; Oltmanns, Marilena (John Wiley & Sons, 2014-12-02)We describe the recent occurrence of a region of diminished sea ice cover or “notch” offshore of the Kangerdlugssuaq Fiord, the site of the largest tidewater glacier along Greenland's southeast coast. The notch's location ... -
U.S. IOOS coastal and ocean modeling testbed : inter-model evaluation of tides, waves, and hurricane surge in the Gulf of Mexico
Kerr, Patrick C.; Donahue, Aaron S.; Westerink, Joannes J.; Luettich, Richard A.; Zheng, L. Y.; Weisberg, Robert H.; Huang, Y.; Wang, H. V.; Teng, Y.; Forrest, D. R.; Roland, Aron; Haase, A. T.; Kramer, A. W.; Taylor, A. A.; Rhome, J. R.; Feyen, J. C.; Signell, Richard P.; Hanson, J. L.; Hope, M. E.; Estes, R. M.; Dominguez, R. A.; Dunbar, R. P.; Semeraro, L. N.; Westerink, H. J.; Kennedy, A. B.; Smith, J. M.; Powell, M. D.; Cardone, V. J.; Cox, A. T. (John Wiley & Sons, 2013-10-08)A Gulf of Mexico performance evaluation and comparison of coastal circulation and wave models was executed through harmonic analyses of tidal simulations, hindcasts of Hurricane Ike (2008) and Rita (2005), and a benchmarking ...