On the physical oceanography of Bristol Bay 1969-1970

Abstract

The examination of hydrographic data obtained in Bristol Bay 1969-1970 allowed oceanographic conditions in this region to be described for shorter time periods (several weeks) than previous studies (several months). This data revealed that during early spring Bristol Bay was homogeneous both vertically and horizontally in temperature and vertically in salinity. During late spring, a steep thermocline developed in the offshore regions and was present throughout summer, while the salinity structure remained vertically homogeneous. Salinity and bottom temperature contours tended to follow isobaths and indicated a cyclonic circulation in the bay. Summer surface temperature distributions are characterized by regions of cold water. These regions are believed to be maintained by upwelling of cold bottom water due to a subsurface convergence in the bottom Ekman layer. Data from 1970 showed that low temperature and high salinity water was much more extensive in that year than in 1969. This is attributed to deeper water from outer Bristol Bay surfacing in central Bristol Bay.