FY 1987

Water properties and circulation in Shelikof Strait, Alaska during 1985

Reed, R.K., J.D. Schumacher, and L.S. Incze

NOAA Tech. Memo. ERL PMEL-68, NTIS: PB87-143053, 35 pp (1986)

Data from cruises in March, July, and October 1985 are used to describe circulation and property distributions, and their changes, in Shelikof Strait. The Alaska Coastal Current flows to the southwest throughout the year, but greatest baroclinic, geostrophic speeds occur in fall when the upper waters are least saline because of a maximum in freshwater discharge. The deep water in the central part of the Strait has its source to the south, and the properties seem to result from vertical mixing of this southern water. Thus Shelikof Strait has an estuarine-like circulation, but the intensity of the northward inflow varies appreciably. Property distributions showed isolines were nearly always deepest on the right side of the channel (looking downstream); greatest baroclinic speeds were often there also. It is believed that differential Ekman pumping may be important to the development of this structure and its changes, at least in some locations. Volume transport estimates for the upper 150 db varied greatly in space and time, with maximum values >10 m s. At times the southwest flow bifurcated, with part continuing along the Alaska Peninsula and the rest exiting the main channel to the south.