Gulf stream meanders off North Carolina during winter and summer 1979

Journal Article · Mon May 30 04:00:00 EDT 1983 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JC088iC08p04633· OSTI ID:6050863

Brooks, D A; Bane, Jr, J M

Meanders produced most of the subtidal variability in the Gulf Stream off North Carolina during 1979. Recording instruments were moored in the lower half of the water column over the 200-m and 400-m isobaths for two periods of 4 months, one of the later winter and one of the late summer. In both seasons, the middepth current speed typically fluctuated between -50 cm s/sup -1/ and +100 cm s/sup -1/ about a 30 cm s/sup -1/ downstream mean. The velocity, temperature, and salinity fluctuations had a prominent weekly time scale in the winter, caused by the meandering stream. In the summer the weekly time scale was less prominent within a generally energetic 3- to 10-day period band. In both seasons, the meandering currents were nearly in phase vertically, and the meanders propagated downstream at approx.40 km d/sup -1/. Shallow in-shore filaments of warm water, separated from the main stream by bands of cooler surface water, are often extruded from the Gulf Stream front during the shoreward-most phase (crest) of meanders. Countercurrents, or upstream flow reversals, often occur under the filaments, forming the shoreward limb of cyclonic frontal eddies which are associated with uplifted cool water found upstream of meander crests. The energy source of the meanders off North Carolina remains obscure. The meandering currents locally transferred their kinetic energy to the mean stream, at about the same rate in each season. The loss of energy is consistent with an asymmetry or skewness of the meander process, often seen in satellite images of the surface temperature. The meandering currents were unrelated to the local wind, or to its curl or divergence, in either season. These results collectively point to an upstream of meander energy, most probably made available by an instability of the Gulf Stream.

• Research Organization: Department of Oceanography, Texas A and M University, College Station, Texas 77843
• OSTI ID: 6050863
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 88:C1; ISSN JGREA
• Country of Publication: United States
• Language: English

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