Seasonal and axial variations of net water circulation and turnover in the estuary of Bilbao.

摘要: Abstract A two-layer box model based on salinity and freshwater inflow data was developed used to estimate net water circulation, contributions of gravitational circulation exchange tide-driven exchange, turnover times for the estuary Bilbao, a small Basque coast (Bay Biscay). Average monthly estimations 2001–2010 period were made related river discharge saltwater inflow. Seasonal variations surface-layer outflows strongly regime, even in lower (inner Abra harbour). Bottom-layer salt-water from outer main driver bottom landward flow, vertical advection outflow inner Abra, but not channelized zone that extends limit harbour tidal limit. Gravitational dominated entire over annual cycle. Tide-driven proportionately increased summer showed highest contribution (42%) August. Flushing residence relation with decrease discharge, although innermost they also high winter due retention at under extremely conditions. time maxima 21.5 28.6 days respectively obtained studied It is note differed largely between upper (flushing 0.4–2.4 days) 2–10 layers zone. Results supported intuitive conclusions drawn previous studies about spatio-temporal dynamics dissolved oxygen, chlorophyll zooplankton populations effect turnover.