Low-Frequency Current Regimes over the Bering Sea Shelf

Using direct current measurements made during the period 1975-81, the authors describe the general circulation over the southeastern Bering Sea and differentiate it by regimes related to depth and forcing mechanisms. Three regimes are present, delineated by water depth (z): the coastal (z less than or equal to 50 m), the middle shelf (50 < z < 100 m), and the outer shelf (z greater than or equal to 100 m). These are nearly coincident with previously described hydrographic domains. Statistically significant mean flow ( similar to 1 to 10 cm s super(-1)) exists over the outer shelf, generally directed toward the northwest, but with a cross-isobath component. Flow of similar magnitude (1-6 cm s super(-1)) occurs in the coastal regime, paralleling the 50 m isobath in a counterclockwise sense around the shelf. Mean flow in the middle shelf is insignificant. Kinetic energy at frequencies < 0.5 cycle per day (cpd) is greater over the outer shelf than in the other two regimes, suggesting that oceanic forcing is important there but does not affect the remainder of the shelf. Kinetic energy in the band from 0.5 to 0.1 cpd follows a similar spatial pattern, reflecting the greater number of storms over the outer shelf.