Complex mean circulation over the inner shelf south of Martha's Vineyard revealed by observations and a high-resolution model
Ganju, Neil K.
Lentz, Steven J.
Kirincich, Anthony R.
Farrar, J. Thomas
MetadataShow full item record
KeywordCoastal and nearshore circulation; Grid resolution; Nesting; Numerical modeling; Tidal rectification
Inner-shelf circulation is governed by the interaction between tides, baroclinic forcing, winds, waves, and frictional losses; the mean circulation ultimately governs exchange between the coast and ocean. In some cases, oscillatory tidal currents interact with bathymetric features to generate a tidally rectified flow. Recent observational and modeling efforts in an overlapping domain centered on the Martha's Vineyard Coastal Observatory (MVCO) provided an opportunity to investigate the spatial and temporal complexity of circulation on the inner shelf. ADCP and surface radar observations revealed a mean circulation pattern that was highly variable in the alongshore and cross-shore directions. Nested modeling incrementally improved representation of the mean circulation as grid resolution increased and indicated tidal rectification as the generation mechanism of a counter-clockwise gyre near the MVCO. The loss of model skill with decreasing resolution is attributed to insufficient representation of the bathymetric gradients (Δh/h), which is important for representing nonlinear interactions between currents and bathymetry. The modeled momentum balance was characterized by large spatial variability of the pressure gradient and horizontal advection terms over short distances, suggesting that observed inner-shelf momentum balances may be confounded. Given the available observational and modeling data, this work defines the spatially variable mean circulation and its formation mechanism—tidal rectification—and illustrates the importance of model resolution for resolving circulation and constituent exchange near the coast. The results of this study have implications for future observational and modeling studies near the MVCO and other inner-shelf locations with alongshore bathymetric variability.
Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): C10036, doi:10.1029/2011JC007035.
Showing items related by title, author, creator and subject.
Eulerian and Lagrangian correspondence of high-frequency radar and surface drifter data : effects of radar resolution and flow components Rypina, Irina I.; Kirincich, Anthony R.; Limeburner, Richard; Udovydchenkov, Ilya A. (American Meteorological Society, 2014-04)This study investigated the correspondence between the near-surface drifters from a mass drifter deployment near Martha’s Vineyard, Massachusetts, and the surface current observations from a network of three high-resolution, ...
Solovev, Mikhail A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1999-09)Climate simulation with numerical oceanic models requires a proper parameterization scheme in order to represent the effects of unresolved mesoscale eddies. Even though a munber of schemes have been proposed and some ...
Hsu, Tian-Jian; Ozdemir, Celalettin E.; Traykovski, Peter A. (American Geophysical Union, 2009-05-14)Wave-supported gravity-driven mudflow has been identified as a major offshore fine sediment transport mechanism of terrestrial sediment into the coastal ocean. This transport process essentially occurs within the wave ...