Summertime synoptic variability of frontal systems in the northern Bering Sea

Hydrographic observations in the northern Bering Sea during August and September 1987 indicate the presence of a front dividing relatively warm, fresh Bering Shelf Water from relatively cool, saline Anadyr Water along the western and northern coasts of St. Lawrence Island near Anadyr Strait. A buoyant layer 20 m thick with surface salinities as low as 29.5 practical salinity units and a maximum temperature of 10°C was present adjacent to the island. The surface outcrop of the front migrated 80 km north during the nine‐day time period of the hydrographic observations. Surface thermal patterns suggest that this front may extend the length of the northern coastline of St. Lawrence Island during the summer. The front veers north and passes through the Bering Strait, where temperature differences as large as 6°C exist across the strait. An examination of the water mass properties of the Bering Sea suggests that the buoyant water north of St. Lawrence Island is Bering Shelf Water which has been carried northward through Anadyr Strait. The baroclinic transport (assuming no flow at the bottom) associated with the front is 0.07 Sv, which is roughly a third of the seasonal increase in transport through the Bering Strait in the summer.