1. The estuarine parameterization problem: sensitivity of ROMS to the specifics of line source buoyancy input in the Coastal Gulf of Alaska A. J. Hermann and E. L. Dobbins JISAO-UW/PMEL

2. Nested model Sea Surface Salinity

4. Observed cross-shelf hydrography

5. A simple salt-wedge estuary Diagrams courtesy of Pritchard

6. Two-layer estuary balances Q/R = Si/(Si-Sq) I small, Sq~0 -> Q~R I big, Sq~Si -> Q>R BUT in either case Q-I=R R Q I Q*Sq I*Si Hq Hi Water Balance: Q = R + I Q - I = R Salt Balance: I*Si = Q*Sq

7. Partially mixed deep estuary -> brackish Q Hi >> Hq; Net outflow = Q at the surface with S=Sq I/Hi small; maybe can ignore? RQ Hq Hi I ROMS

8. Totally mixed shallow estuary -> brackish R! Hi, Hq -> 0 ; Net outflow = R at the surface with S > 0 Nothing happening further down RQ-I=R Hq Hi ROMS

9. 4 tests Near-surface river Dambreak river Partially mixed deep estuary Totally mixed shallow estuary

10. SchemePROCON Near-surface river (tip of salt wedge) S=0, Q=R Maximal at surface (linear ramp) Model caculates mixing Model caculates mixing simple simple Get thin bore in deep waters Get thin bore in deep waters Push estuary offshore Push estuary offshore Dambreak river (far upstream of salt wedge) S=0, Q=R vertically uniform Model calculates mixing Model calculates mixing simple simple Get thin bore in deep waters Get thin bore in deep waters Push estuary offshore Push estuary offshore Partially mixed deep estuary S>0, Q>R all at surface More like a typical estuary More like a typical estuary Uncertain parameters Uncertain parameters We ignore return flow at depth We ignore return flow at depth Huge flows at surface! Huge flows at surface! Totally mixed shallow estuary S>0, Q=R all at surface Simple Simple Assimilates data Assimilates data Highly idealized Highly idealized Assimilates data Assimilates data

11. Modeled Surface Salinity

12. Modeled cross-shelf salinity

13. Models vs data early March 2001 Model Data Model Data

14. Models vs data late July 2001 Model Data Model Data

15. Mid-shelf salinity profile: near-surface river vs. data

16. Mid-shelf salinity profile: tot mixed shallow estuary vs. data Model Data Model Data

17. Partially-mixed estuary (yellow, green) yield excess transport compared to data (black). Tot mixed shallow estuary (pink) is better Near-surface river (blue) yields too much stratification compared to data (black). Tot mixed shallow estuary (pink) is better

18. Conclusions so far None of the solutions is ideal; there is no simple substitute for a real estuary None of the solutions is ideal; there is no simple substitute for a real estuary Pure river approaches are too fresh at surface - > Runaway estuary effect on shelf Pure river approaches are too fresh at surface - > Runaway estuary effect on shelf Partially mixed deep estuary yields too much outflow, overwhelms system Partially mixed deep estuary yields too much outflow, overwhelms system Totally mixed shallow estuary is best one so far! Totally mixed shallow estuary is best one so far!