CIRCULATION OF PRINCE WILLIAM SOUND, ALASKA

The circulation of Prince William Sound, Alaska, is described using hy drographic (1974-1989), current meter (1977-1979), and acoustic Dopple r current profiler (1986-1990) observations from both the sound and th e adjacent Gulf of Alaska. Ancillary data include data for winds, fres hwater runoff, and satellite-tracked drifters. Prince William Sound is a small inland sea in that it is wide enough to have appreciable hori zontal cyclonic circulation. It is also a fjord in that it has basin d epths to 700 m but is stilled at 180 m to the open ocean. The general circulation pattern is defined by a portion of the westward flowing Al aska Coastal Current on the Gulf of Alaska shelf that enters Prince Wi lliam Sound through Hinchinbrook Entrance and transits the sound from east to west before exiting through Montague Strait and rejoining the coastal current. However, there is much variability in this circulatio n, especially in the transport through Hinchinbrook Entrance. In addit ion, some of the water entering the sound becomes involved in the cycl onic circulation in the northern sound and so has a longer residence t ime. The circulation is strongly mediated by seasonal and interannual variations in winds and freshwater runoff as well as by local topograp hy both inside and outside the sound. In winter, the strong cyclonic w inds over the Gulf of Alaska cause coastal downwelling and strong flow in the upper layers into Prince William Sound through Hinchinbrook En trance and out through Montague Strait. In summer, the downwelling cea ses, allowing subsurface denser water to rise above the sill and flow into the sound through the bottom layers of Hinchinbrook Entrance. We conclude that the best transport data came from Montague Strait, from which we estimate that approximately 40% of the volume of Prince Willi am Sound is flushed in summer (May-September). This estimated volume r ises to about 200% in winter (October-April).