ON THE FLOW FIELD IN THE CHIRIKOV BASIN

Current measurements from moorings in the Anadyr, Shpanberg and Bering straits and the Chirikov Basin each year from 1985 to 1988 over the summer production period (June-September) shed new light on the regional flow regime. Analyses focus on water conservation and residence times in the Chirikov Basin and the relationships between flows and regional wind field. The primary finding is the existence of two flow modes, a ''Summer'' mode lasting for 2-4 months each year, then a sharp transition about the middle of August each year to a ''Fall'' mode which prevails until the following April, May or June; periods of low flow variability as long as one month at other times of the year do not establish Summer flow conditions. All aspects of the flow field differ depending on which mode is active: north transport, coupling of flow to local winds, flow energy, incidence of flow reversals, and residence times. The cause for the modal behavior is marked differences in both the speed and direction of local winds and the degree of north-south wind divergence-convergence over the Bering Strait region. Analyses of flow reversals in one or more of the straits (there are four patterns) show how they are related to the regional winds.