Observation of Shelfwater Overrunning the Southern Slope Sea

<p>Analyses of two years (1992 and 1993) of high resolution (1.47 km²) sea surface temperature satellite images of the southern Mid-Atlantic Bight (MAB), showed that unusually extensive overhang of shelf water occurs episodically, and coherently over along shelf distances of several hundred kilometers. These episodes are dubbed overrunning of the Slope Sea by shelf water. The overrunning volume has a "face" and a "back" (southern and northern limit). It transports substantial quantities of shelf water southward, and does not retreat onto the shelf, but eventually joins the western edge of the Gulf Stream in the vicinity of Chesapeake Bay.</p> <p>The correlation between satellite and <em>in situ</em> surface temperature, the location of shelf-slope front, and the relation of surface temperature to the deeper water mass were explored in order to quantify the overrunning episodes. The satellite extracted temperature profile agreed well with<em> in situ</em> surface temperature and coincident Expendable Bathythermographs (XBT) transects. The combined analyses of satellite imagery and various i<em>n situ</em> data further demonstrated that the shelf water that over-run the Slope Sea are not mere surface features but can reach depths between 40 ∼ 60 m.</p> <p>Results confirm previous concepts on shelf circulation, shelf-slope exchange, fate of shelf water. They also sheds new light on shelfwater budget: overrunning of Slope Sea and southwest transport by upper slope current constitutes an important conduit for shelf water transport.</p> <p>Further analyses of potential causes for the overrunning events showed that wind stress due to winter storms moved the shelf-slope front and with it shelf water offshore to distances ∼10 to 40 km. The offshore displacement of shelf water also appeared to be related to the onshore veering of the Gulf Stream near Cape Hatteras. This veering of the Stream caused sea level to rise near Cape Hatteras producing a blocking effect on the shelf circulation. Such a blocking effect of the southwestward flow of shelf water in the MAB appeared to be the reason for the overruning of shelf water off New Jersey. In addition, the excess fresh water discharge from the St. Lawerence is also observed to be related to the flooding of shelf water off New Jersey.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Ocean & Earth Sciences

Year dc:date.available

1996

Author dc:creator

• Kumar, Ajoy

Contributors dc:contributor

• G. T. Csanady
• Larry P. Atkinson
• William C. Boicourt
• Arnoldo Valle-Levinson

• Remote sensing
• Slope Sea
• Shelfwater
• Geophysics and Seismology
• Oceanography

Statement dc:rights

• <p>In Copyright. URI: <a href="http://rightsstatements.org/vocab/InC/1.0/">http://rightsstatements.org/vocab/InC/1.0/</a> This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).</p>

Identifier

9780591048643

OAI identifier oai:identifier

oai:digitalcommons.odu.edu:oeas_etds-1052