ON THE IMPLEMENTATION OF A 3-DIMENSIONAL CIRCULATION MODEL FOR PRINCE-WILLIAM-SOUND, ALASKA

The POM (Princeton Ocean Model), a three-dimensional, primitive equati on ocean circulation model, is applied to Prince William Sound, Alaska . A 3-D concentration equation for passive tracers is added to POM to explore transport pathways and rates, plus retention zones and residen ce times. The 3-D structures of the current, density, and passive trac er concentration are examined for realistic bottom topography, idealiz ed Alaskan coastal water inflow/outflow and idealized wind-forcing. Ba sed on observational evidence and ecological concerns, the 'lake/river hypothesis' (i.e, the effect of weak versus strong throughflow on the ecology of the Sound) is explored to determine its influence on the c irculation and transport patterns of passive tracers. Strong inflow th rough Hinchinbrook Entrance (river-like case) is crucial to the vigoro us cyclonic circulation in the Sound and strong coupling to offshore i nfluences, while with a weak inflow (lake-like case), the circulation in the Sound is much weaker and weakly coupled to offshore influences. The strength of the inflow and the wind direction are particularly im portant for determining the nature of the secondary branches of the th roughflow in the northwestern Sound and the position, strength, and nu mber of cyclonic and anticyclonic gyres, Mesoscale eddies are induced in the deep basins that have not yet been studied observationally. The advection of buoyant (relatively fresh) coastal water into the Sound significantly influences the circulation pattern and upper-layer densi ty stratification. Idealized winter and summer wind-forcing generate d istinctive surface circulation patterns that are important to the tran sport pathways, residence times, and retention zones of passive tracer s; for example, northward and westward winds increase the northernmost penetration of passive tracers entering the Sound from offshore and t he residence time substantially. (C) 1998 Elsevier Science Ltd, All ri ghts reserved