Wind Stress on the Ocean over the Eastern Continental Shelf of North America

Abstract

Abstract Employing one million ship reports gathered in the years 1941–72 seasonal averages of the wind stress and its standard deviation have been computed for the shelf region of the eastern North American continent (out to a depth of 200 m). A drag coefficient is assumed which increases with wind speed, from 1.0×10−3 at 5 m s−1 to 2.3×10−3 at 25 m s−1. Atmospheric stratification is taken into account but its effect is shown to be small. In the summer season the 32-year climatological wind stress is toward the northeast, having a magnitude close to 0.25 dyn cm−2 throughout the entire shelf region. In the three other seasons the stress is directed toward the south and east being strongest in winter (1–1.5 dyn cm−2) and weakest in fall (0.25–0.5 dyn cm−2). In addition to the expected increase in magnitude with increasing latitude remarkable small-scale variability occurs. An offshore increase in stress is widespread and dominates the mid-Atlantic Bight; in winter the stress there increases from 0.5 to 1.0...