Intrusions of Gulf Stream waters onto the South Atlantic Bight shelf

Abstract

Intrusions of Gulf Stream waters onto the South Atlantic Bight continental shelf are analyzed using historical observations spanning several decades. Intrusions of dense water near the bottom occur predominantly during summer, when they are observed 30% of the time at the middle and outer shelf, but less frequently (<10%) inshore of the 20 m isobath, where they are found predominantly following periods of strong upwelling favorable winds. Bottom intrusions can have an important effect on stratification, especially on the outer shelf, where the average near-bottom temperature is 2C lower when bottom intrusions are present. Surface intrusions, on the other hand, occur more evenly distributed throughout the year, although they are more frequent during summer, when they also tend to reach farther onshore. Surface intrusions occur slightly more frequently during times when winds are downwelling favorable. Both surface and bottom intrusions are more frequently observed in the northern and southern South Atlantic Bight, where the shelf is narrowest, and less frequently in the wider central region. Copyright 2011 by the American Geophysical Union.