Summer and Winter Hydrography of the U.S. South Atlantic Bight (1973-1979)

Abstract

Hydrographic data from winter and summer cruises during the period 1973 to 1979 were used to illustrate oceanographic conditions in the South Atlantic Bight (SAB).During this period meteorological conditions resulted in unusually low water temperatures in near shore regimes (<6°C in South Carolina coastal waters in January 1977). During other winter cruises surface waters were cooler off Georgia than off South Carolina. Zones of upwelling were observed regularly near Cape Canaveral and off Charleston, while Gulf Stream intrusions were detected at many outer shelf locations. Low salinities indicative of runoff (< 35 ‰) occurred near the coast from South Carolina to Florida during both winter and summer cruises with a surface salinity of 27 ‰ off the Georgia coast during the winter 1973 cruise. High salinity water (36 ‰) was also present during the winter cruises in some coastal areas, indicating Gulf Stream intrusions. Surface salinities 35 ‰ near river mouths during summer cruises corresponded to drought conditions in the coastal states. Surface circulation, as derived from density distributions, indicated both typical and atypical patterns during this study. The cyclonic eddy normally in Long Bay (south of Cape Fear) was not well-defined during most of our cruises or was simply outside of our sampling area. During all cruises the coastal countercurrent was present, but was continuous from Long Bay to Cape Canaveral only during the summer except for winter 1977.