Semidiurnal bottom pressure and tidal currents on Georges Bank and in the Mid-Atlantic Bight

Abstract

Observations of the semidiurnal (M 2 ) tidal current, bottom pressure, and coastal sea level from Nova Scotia to Cape May, New Jersey) show that: 1) the surface pressure at the edge of the Continental Shelf in the study area has a relatively uniform amplitude (40 cm) and phase (12 hr Greenwich); 2) in the Mid-Atlantic Bight, the semidiurnal M 2 tide is co-oscillating, and the onshore M 2 tidal current reaches a maximum 2 approximately 90° or 3.1 hr before high water; 3) in the Georges Bank region of the shelf, the M tide is more progressive than it is in the 2 Mid-Atlantic Bight, and the onshore M 2 tidal current in the Georges Bank 2 region of the shelf reaches a maximum about 7 ° or 14 min before high water; 4) the strongest M 2 tidal currents observed in the study area are 2 near the crest of Georges Bank (typical amplitudes are 74 cm/s near the surface); 5) the M 2 tidal currents are weaker in the Mid-Atlantic Bight 2 (typical amplitudes are 16 cm/s near the surface) than on Georges Bank; and 6) the tidal currents are weakest near the bottom south of Cape Cod in a region of transition between progressive and co-oscillating tides.