Paul McWilliams – Ocean 101 Spring 2004 Exploring Puget Sound Tides & Currents with the Acoustic Doppler Current Profiler (ADCP) Paul A. McWilliams

Paul McWilliams – Ocean 101 Spring 2004 Presentation Outline 1.Tides (Sat & Fri) 2.Predicted Currents 3.The ADCP 4.Data Samples Contours Profiles 5.Questions

Paul McWilliams – Ocean 101 Spring 2004 Tides for 8 &14 May, 2004 Saturday May 8 Spring Ebb Range=13.3ft Low 2:07 AM 7.2 High 6:53 AM 10.4 Low 2:17 PM -2.9 High 10:04 PM 11.5 Maximum Ebb ~10:36AM Friday May 14 Neap Flood & LHW Tidal Range=5.2ft High 2:33 AM 11.1 Low 9:10 AM 2.8 High 3:10 PM 8.0 Low 8:33 PM 3.5 Max Flood ~12:13pm

Paul McWilliams – Ocean 101 Spring 2004 Ebb Tide (Sat) Expected Flow North in central Puget Sound South from Possession Sound West Through Admiralty Inlet

Paul McWilliams – Ocean 101 Spring 2004 Flood Tide (Fri) Expected Currents East through Admiralty Inlet South in Central Sound North in Possession Sound

Paul McWilliams – Ocean 101 Spring 2004 Current Predictions Saturday May 8 Stronger Currents Northward Flow during Ebb Tide Westward Flow in the near Edmonds Friday May 14 Weaker Currents Southward flow during Flood Tide

Paul McWilliams – Ocean 101 Spring 2004 Acoustic Doppler Current Profiler (ADCP) Uses compression and expansion of reflected sound-waves to measure the movement of particles in the water Requires significant Processing power- Microprocessors Make Possible Must take Ship ’ s Motion into account (GPS)

Paul McWilliams – Ocean 101 Spring 2004 ADCP Limitations Cannot “ see ” bottom 15% of Water Depth or Near Surface –Backscatter –Surface Noise GPS Precision — Ship ’ s Pitch and Roll not Accounted For

Paul McWilliams – Ocean 101 Spring 2004 Three Types of Displays Contour Detail Contour Profile

Paul McWilliams – Ocean 101 Spring Types of Data Direction Magnitude North Velocity East Velocity Error Vertical

Paul McWilliams – Ocean 101 Spring 2004 GPS Navigation Processing Friday PM leg Contours without and with (bottom) Navigation Processing

Paul McWilliams – Ocean 101 Spring 2004 Direction Contours Sat (Top) versus Fri (Bottom) Color Code: Magenta=North Blue=East Green=South Orange=West

Paul McWilliams – Ocean 101 Spring 2004 Magnitude Contours Saturday (top) Versus Friday (bottom) Color Code: Magnitude (mm/s) Red=700 Blue=0

Paul McWilliams – Ocean 101 Spring 2004 North Velocity Saturday (top) Versus Friday (Bottom) Color Code: Warm=“+”or N Cool=“–”or S +/-700mm/s

Paul McWilliams – Ocean 101 Spring 2004 East Velocity Saturday (top) Versus Friday (Bottom) Color Code: Warm=“+”or E Cool=“–”or W +/-700mm/s

Paul McWilliams – Ocean 101 Spring 2004 Profile Examples-Max Ebb Saturday West Point 10:36am Velocity Green”+”=N Red”+”=East

Paul McWilliams – Ocean 101 Spring 2004 Profile Examples-Max Flood Friday Edmonds 12:13pm Velocity Green”+”=N Red”+”=East

Paul McWilliams – Ocean 101 Spring 2004 Profile Examples-Friday Cast 3 Friday ORCA 2 3:40pm (high slack) Velocity Green”+”=N Red”+”=East

Paul McWilliams – Ocean 101 Spring 2004 Questions? For More Information:

Paul McWilliams – Ocean 101 Spring 2004 Conclusions Predictions seems accurate –ADCP seems to work –Currents are strongly tide based Point Wells seems okay for discharge Need to look at –full range of tides –Storm conditions