Seasonal and low frequency variations in dynamic height anomaly and transport of the Gulf Stream

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One hundred and thirty pairs of hydrographic stations bracketing the Gulf Stream between Cape Hatteras and the New England Seamounts are used to study seasonal and low frequency changes in dynamic height and baroclinic transport. The data span a 56-year period from 1932 to 1988. The stations were selected from hydrographic sections as representative of conditions immediately outside the current on the Slope Water and Sargasso Sea sides. It is found that the dynamic height anomaly is maximum in the fall and it is almost entirely governed by the annual heating and cooling cycle. The baroclinic transport is calculated from the potential energy anomaly difference between stations located just outside of the northern and southern edges of the Gulf Stream. The annual cycle in the 0-2000 dbar baroclinic transport is maximum in early summer, with a peak to peak range of (8 ± 3) Sv. Low frequency changes in transport, after removing the annual cycle, arc difficult to discern with confidence due to eddy variability. However, there is evidence of a 6 Sv decrease in transport between the late 1950s and early 1970s. © 1995.

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Deep-Sea Research Part I