Accession Number : ADP001040

Title :   A Seasonal Comparison of Gulf Stream Fluctuations off North Carolina,


Personal Author(s) : Brooks,David A. ; Bane,John M. , Jr

Report Date : APR 1982

Pagination or Media Count : 31

Abstract : The Gulf Stream Meanders Experiment (GSME) was conducted off North Carolina in 1979. Instruments were moored in the Stream over the 200 m and 400 m isoabaths on the continental slope for two 4-month periods, one in the winter and one in the summer. In both seasons, the downstream current speed typically fluctuated between -50 cm/s and +100cm/s about a 30 cm/s mean. The velocity, temperature, and salinity fluctuations had a prominent 7- to 10-day period in the winter, and a less prominent 5- to 7-day period in the summer. The fluctuations, which were nearly in-phase vertically and propagated down-stream at approx. 40 km/d, apparently resulted from lateral, wavelike excursions or meanders of the Gulf Stream front, as first described by Webster (1961a). The observed structure is complicated along the shoreward edge of the Stream, where shallow surface filaments of warm water often trail southwestward from meander crests. The warm filaments are usually separated from the Stream by a band of cool surface water, which is a manifestation of deeper uplifting or upwelling associated with the meander process. Strong cyclonic circulation around the uplifted cool water pool is a characteristic feature of meanders. In both seasons, the leading term in the energy equation indicated that part of the fluctuation kinetic energy was converted to mean Stream kinetic energy, with an implied doubling time of a few weeks. Direct forcing by the wind was found to be ineffective during the GSME. The seasonal persistence of meanders in the GSME area thus indicates an upstream source of their kinetic energy. (Author)

Descriptors :   *Ocean currents, Gulf Stream, North Carolina, Continental slopes, Velocity, Temperature, Salinity, Seasonal variations, Statistical analysis

Distribution Statement : APPROVED FOR PUBLIC RELEASE