FY 1983

Winter currents on the eastern Bering Sea shelf

Salo, S.A., J.D. Schumacher, and L.K. Coachman

NOAA Tech. Memo. ERL PMEL-45, NTIS: PB83-248823, 53 pp (1983)

An analysis of fifteen current records from thirteen locations over the central and northern Bering Sea shelf is presented. Four moorings were deployed over the 1976/77 and 1977/78 winters and five over winter 1980/81. Comparison of current and kinetic energy characteristics showed a difference between records from north and south of St. Lawrence Island. To the north, circulation was dominated by northward mean flow (4–15 cm/s), and tides accounted for only 24 ± 13% of the total kinetic energy of fluctuations. In contrast, mean currents south of St. Lawrence Island exhibited greater variation in direction, were generally 1 to 4 cm/s in magnitude and tides accounted for about 55 ± 31% of the fluctuating kinetic energy. Although vector-mean currents in both regions were in general northward, and approximately parallel to local bathymetry, frequent reversals occurred. One reversal, coincident with northerly winds, occurred at all sites and persisted for more than two weeks; such current reversals affect the flow over thousands of square kilometers. The presence of ice appears to affect the flow by reducing the impact of direct wind stress as driving force.