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The Northern California Current 2002 Cold Halocline, High Productivity and Hypoxity

The Northern California Current 2002 Cold Halocline, High Productivity and Hypoxity. A. Huyer, R. L. Smith, P. Wheeler COAS, Oregon State University with help from H. Freeland Institute of Ocean Sciences. Line P and Globec LTOP Sections. Line P: Jun-Jul 2002. NH: Feb, Apr, Jul,

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The Northern California Current 2002 Cold Halocline, High Productivity and Hypoxity

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  1. The Northern California Current 2002Cold Halocline, High Productivity and Hypoxity A. Huyer, R. L. Smith, P. Wheeler COAS, Oregon State University with help from H. Freeland Institute of Ocean Sciences

  2. Line P and Globec LTOP Sections Line P: Jun-Jul 2002 NH: Feb, Apr, Jul, Sep, Dec 02 CR: Apr, Jul, Dec 02 (Surface Elevation for July-August from Strub & James, 2002)

  3. Overview of NH-line, 2001-2002 • Temperature • Normalized Temperature Anomaly • Salinity • T-S at Shelf Break

  4. NH Temperature, 2001 & 2002 Winter Spring Summer Sept Fall

  5. Enhanced CUC, El Niño? Cold Halocline NH Normalized Temperature Anomalies2001 &2002 Winter Spring Summer Sept Fall

  6. Drought NH Salinity, 2002 & 2002 Winter Spring Summer Sept Fall

  7. Drought Cold Halocline Enhanced CUC, El Niño? NH Shelf-Break T-S, 2001 & 2002 Winter Spring Summer Sept Fall

  8. The Cold Halocline Anomaly • Off central Oregon (NH off Newport) • Along Line P • Off northern California (CR off Crescent City) • Cause: Alongshore Advection?

  9. NH-Line Temperature July 2001 and 2002 (and difference)

  10. Vertical Profiles of T, SNH - Line Offshore (NH-85) Shelf-Break (NH-25)

  11. NH-Line TS: Cold Halocline Shelf-Break (NH-25) Offshore (NH-85)

  12. Line P, Slope T-S: Cold Halocline June 2002 previous June, July Howard Freeland, IOS, Aug 2002

  13. Line P Temperature Anomaly, June-July 2002 Howard Freeland, IOS, Sept 2002

  14. Line P Temperature Anomaly (Argo O-A) Howard Freeland, IOS, Aug 2002

  15. CR-Line TS Upper Slope (CR-4) Offshore (CR-9 or CR-11)

  16. Probable Causes of Cold Halocline Alongshore Advection? • large-scale gradients -> displacement of 500 km • coastal sea levels down by 10 cm -> surface current anomaly of 10 cm/sec (if width is 100 km) -> 3 month duration -> displacement of 1000 km • halocline currents weaker than surface -> alongshore advection is likely cause Zonal Advection? Winter Mixing? Reduced Coastal Downwelling?

  17. Temperature Salinity Depth s=26.0, NH-Line, July 2002

  18. Coastal Sea Level AnomaliesSeward to Crescent City, 2001-2

  19. Consequences in Coastal Upwelling Ecosystem • High Nutrients in upwelling water • High Chlorophyll (Fluorescence) inshore • High oxygen in photic zone inshore • Low oxygen near bottom over inner shelf

  20. NH-Line, July 2002Temperature, Depth at S=33.0

  21. 2002 NH- Line Nutrients in Halocline ( at S= 33.0) 1998 2001 2000 1999 Net increase at NH-25, NH-35 Nitrate 12 mmole Phosphate 0.8 mmole Silicate 14 mmole (Wheeler, OSU, 2002) 0 km 100 km Distance from shore

  22. 40 40 70 0 0 0 NH- Line Shelf-Break Nutrients vs Salinity (NH-25) 31.5 34.5 (Wheeler, OSU, 2002)

  23. 5-m Underway Fluorescence NH-Line Full Scale July 2000July 2001July 2002 ( J. Fleischbein, Nov 2002)

  24. July 2002 July 2000 5-m Underway Fluorescence (Fleischbein, OSU, 2002)

  25. DO < 1.0 ml/l Hypoxia over Inner ShelfNH-Line, July 2002 Density Dissolved Oxygen

  26. Supersaturated NH-3 NH-5 NH-1 Hypoxic Inner Shelf NH-Line, July 2002Oxgen vs Salinity NH-15 NH-10

  27. Acknowledgments • GLOBEC NEP • NSF, NOAA • Jane Fleischbein, OSU • Germaine Gatien, IOS

  28. Coastal Upwelling AnomaliesSeward to Crescent City, 2001-2

  29. 150 km 100 50 0 km 0 m 46 N 500 m 1000 m 45 N 1500 m 2000 m 2500 m 44 N 126 W 124 W 122 W Typical Sampling of NH-Line 1961-1971 & 1997-2003TENOC (bottles) & GLOBEC(CTD) Depth (m) 126 W 125 W 124 W

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