Observations of Coastal Upwellings along the Northern Beaches of the
North Carolina Outer Banks
Observations of coastal upwelling of cold, nutrient rich, oceanic water have been reported along the Mid Atlantic Bight, specifically the coastlines of New Jersey, and Long Island (Neuman, 1996, & Glenn et al. 1996). If seasonally persistent, these events, and their associated blooms of microorganisms can ultimately lead to a transient enrichment of local marine life, but also have the potential to produce subsequent depressed levels of dissolved oxygen due to increased rates of organic consumption and decay. The anoxic conditions thus created can be very harmful to indigenous benthic biota.
Analysis has indicated that the upwelling along the coast of NJ and other coastal regions, wherein cold bottom water displaces warmer surface water, occur on the down-slope side of topographic “highs” or shallow ocean bottom ridge-lines (Glenn et al, 1996). The events themselves are apparently triggered by persistent strong surface winds blowing out of the South with a component parallel to the local shoreline. In the case of the southwest to northeast running of the New Jersey coast, this is most typically seen during periods of southwesterly winds. In the case of the East to West oriented Long Island bight, upwelling seems to accompany winds out of the West.
The portion of the North Carolina Bight south of the Chesapeake Bay entrance and northward of Cape Hatteras, is oriented slightly northwest to southeast so coastal upwelling might be expected to be driven by seasonal winds out of the South-southeast. If such events do occur, they might also occur downwind of topographic highs in similar to the upwelling events seen further north. Another geographic similarity between the Jersey Shore and Northeast North Carolina coastline that may impact upwelling phenomena is the proximity to the large drainage plumes of the Hudson River and the Chesapeake Bay that flow into continental shelf waters and may influence coastal upwelling dynamics.
The URE-OMS Remote Sensing Team students are examining historical AVHRR derived, level-three sea surface temperature image data (obtained from the Rutgers University Coastal Ocean Observation Laboratory, RU-COOL) to determine the presence of local upwelling events and attempting to establish their possible correlation with archived wind data recorded at the Hatteras National weather service station and at the U.S. Army’s Duck Field Research Facility obtained from the North Carolina online Climate Data Center at http://www.nc-climate.ncsu.edu
The search for seasonal upwelling events includes image data from June 1st through August 15th, of 2000 and their possible correlation with topographic highs as revealed by the most current NOAA Hydrographic charts of the region.
If a strong correlation with persistent wind direction can be shown to exist then current wind data from local and satellite sources such as NOAA buoys and the NASA QuickScat sensor provided on a public web site could be a means to alert marine authorities, marine agricultural interests and the public to the possible risk of anoxic events which might do considerable harm to the local shell or sport fishing industry.