Interannual and Seasonal Along-Shelf Current Variability and Dynamics: Seventeen Years of Observations from the Southern New England Inner Shelf

Abstract The characteristics and dynamics of depth-average along-shelf currents at monthly longer time scales are examined using 17 years observations from the Martha’s Vineyard Coastal Observatory on southern New England inner shelf. Monthly averages depth-averaged current almost always westward, with largest interannual variability in winter. There is a consistent annual cycle westward 5 cm s −1 summer decreasing to 1–2 Both predominantly driven by wind stress. In absence forcing, there flow ∼5 throughout year. At scales, momentum balance primarily between stress, surface gravity wave–enhanced bottom an opposing pressure gradient that sets up along shelf response wind. Surface wave enhancement stress substantial over essential accurately estimating variation across Significance Statement Seventeen continental reveal stronger than variations around opposed less 30 m water determining