1. Vertical Structure of the California Current System Hoke Seamount Cruise 2004 OC3570 07 SEP 2006
LT Alicia Hopkins

2. California Current System?
What is the
California Current System?

4. The current that runs southward along our coast is known as the California Current. This current moves cold water from the Gulf of Alaska along our coast and is partially responsible for the relatively cold water we experience when we go to the beach.

5. AL CA

6. California Current System
CA Current (CC)
Surface flow
3000km down the coast
1000km wide
Cool, fresh, oxygenated water
Davidson Current (DC) California
Weaker surface flow
Seasonal
Undercurrent (CUC)
Subsurface flow
Along continental slope

8. Southern California Bight
Southern California Countercurrent
Southern California
Eddy

9. A bight is defined as a recessed region of the coastline that alters the normal current flow. The Southern California Bight (SCB) extends from Point Conception to Cabo Colnett, south of Ensenada, Mexico, covering 300 km of coastline. The SCB is an area of coastal upwelling, characterized by cold, nutrient rich water capable of supporting a large variety of organisms. The California Current System flows through the SCB. The California Current flows southward off shore, carrying cold, subarctic waters. The California Undercurrent flows northward inshore, carrying warm, equatorial waters. A venturi effect causes the California Current to eddy within the SCB creating the California Countercurrent, which carries surface waters northward.

10. R/V New Horizon

14. Vertical Structure
of the Hoke 2004
CTD Data

15. Temperature

18. Top Down View
Not a simple, unidirectional flow, but a series of large eddies superimposed on a broad, weak, equatorward movement.The coastal flow is particularly complex.

19. Above is a satellite-derived Sea Surface Temperature (SST) image of the Southern California Bight from September 30, 1995.    Cold, equatorward waters as designated by blue pixels are visible to the north and offshore (west), whereas warm, generally poleward waters as designated by red and orange pixels are visible to the south and nearshore (east). This SST product was derived from Advanced Very High Resolution Radiometer (AVHRR) data

20. Variability CCS not stable fluctuates in space and time
meanders, eddies, & filaments
influence the large scale flow
affect the physical properties (T, S, P)

22. c

23. c

24. Salinity

27. c

28. c

29. T-S Plot

30. Shallow – differences in salinity
Warm, salty
Nearshore, Equatorial
Cold, fresh
cool/fresh surface waters, warm/saline below ~100 dbar;
distinct water masses ~ dbar – CC and CUC
Offshore, sub-Arctic
Deep - Colder salty water

31. Spice Positive. warmest, saltiest waters Negative
Spice Positive warmest, saltiest waters Negative coldest, freshest waters

32. c
Subsurface MAX - Warm, salty indicates CU/SCC waters

33. Subsurface 250 dbar
Warm, salty – indicates CU/SCC

35. Dissolved O2
High O2
Sub-Arctic waters
Low O2
Equatorial waters

36. Subsurface MAX
2 MIN:
CU - EQ waters
Canyon – water away from surface for a long time – a result from basin waters coming from CU
Lack of overturning

39. Fluorometer

40. MAX: near coast, smaller offshore
- SCC advects low oxygen waters to surface while high productivity fuelled by nutrient enrichment creates regions of high O2 near the coast

42. Conclusion

43. c

44. Variability CCS not stable fluctuates in space and time
meanders, eddies, & filaments
influence the large scale flow
affect the physical properties (T, S, P)

45. QUESTIONS?