Upwelling rebound, ephemeral secondary pycnoclines, and the creation of a near‐bottom wave guide over the Monterey Bay continental shelf. Issue 23 (5th December 2014)

• Record Type: Journal Article
• Authors: Cheriton, Olivia M.; McPhee‐Shaw, Erika E.; Storlazzi, Curt D.; Rosenberger, Kurt J.; Shaw, William J.; Raanan, Ben Y.
• Is Part Of: Geophysical research letters. Volume 41:Issue 23(2014:Dec.)
• Page Start: 8503
• Page End: 8511
• Publication Date: 2014-12-05
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2014GL061897
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Several sequential upwelling events were observed in fall 2012, using measurements from the outer half of the continental shelf in Monterey Bay, during which the infiltration of dense water onto the shelf created a secondary, near‐bottom pycnocline. This deep pycnocline existed in concert with the near‐surface pycnocline and enabled the propagation of near‐bottom, cold, semidiurnal internal tidal bores, as well as energetic, high‐frequency, nonlinear internal waves of elevation (IWOE). The IWOE occurred within 20 m of the bottom, had amplitudes of 8–24 m, periods of 6–45 min, and depth‐integrated energy fluxes up to 200 W m −1 . Iribarren numbers (<0.03) indicate that these IWOE were nonbreaking in this region of the shelf. These observations further demonstrate how regional upwelling dynamics and the resulting bulk, cross‐margin hydrography is a first‐order control on the ability of internal waves, at tidal and higher frequencies, to propagate through continental shelf waters. Key Points: Under upwelling, a near‐bed pycnocline appeared on outer Monterey Bay shelf High‐frequency nonlinear internal waves of elevation propagated near seabed Regional upwelling dynamics control propagation of internal waves over the shelf