1. The Alaskan Coastal Current Presented by: Gerry Butrico

3. The Alaskan Coastal Current Formed by storm systems associated with the Aleution Low Formed by storm systems associated with the Aleution Low Results in persistent cyclonic winds that impel onshore surface Ekman Transport and costal downwelling Results in persistent cyclonic winds that impel onshore surface Ekman Transport and costal downwelling Year round current, trapped near the coast Year round current, trapped near the coast Forced by wind and buoyancy Forced by wind and buoyancy Most prominent circulation of the Gulf of Alaska’s continental shelf Most prominent circulation of the Gulf of Alaska’s continental shelf

4. The Alaskan Coastal Current Precipitation is a result of winds blowing over the mountains near the coast Precipitation is a result of winds blowing over the mountains near the coast The coast is on the windward side of the Mountains The coast is on the windward side of the Mountains Rainfall between 2-6 m/yr Rainfall between 2-6 m/yr Wind stress and runoff have seasonal variability Wind stress and runoff have seasonal variability –Wind is strong in winter, weak in summer

5. The Alaskan Coastal Current Runoff is weak in the winter because most of the precipitation is stored as snow along the coast. Runoff is weak in the winter because most of the precipitation is stored as snow along the coast. Strongest during summer thaw and rain Strongest during summer thaw and rain Runoff causes lower salinity near the surface Runoff causes lower salinity near the surface –Controls horizontal and vertical density gradients.

7. The Alaskan Coastal Current Freshwater runoff flows on top of the denser salt water. Freshwater runoff flows on top of the denser salt water. The coriolis force, along with the coastal down welling caused by Ekman Transport causes the buoyant water to flow as a current The coriolis force, along with the coastal down welling caused by Ekman Transport causes the buoyant water to flow as a current

9. The End Source: Weingarther, Thomas J., Seth L. Dainelson, Thomas C. Royer, 2005: Freshwater variability and predictability in the Alaska Costal Current, Deep Sea Research II, 52, 169-191.