Turbidity in Monterey Bay: Operational Oceanography Winter 2009 Project Rip Coke 16MAR09

Outline Motivation MIW Threat Area Equipment Data Set Analysis and Calculations Conclusions References

Driving Force MIW Thesis Importance of turbidity in detection and classification operations Dive Operations RMV Maneuvering MP Placement http://www.onr.navy.mil

Adapted by Nicky Wheatley from NRC: Oceanography for Mine Warfare MIW Threat Various degrees of mine threats (depth depending) 0-25m is a critical zone Surf Zone 0 – 3m Obstacles Anti Invasion Bottom Moored Drifting Shallow Water 12 – 60m Moored (Rising) Very Shallow Water 3 – 12m Deep Water > 60m Adapted by Nicky Wheatley from NRC: Oceanography for Mine Warfare

Acoustic Doppler Current Profiler (ADCP) Primary tool for measuring the sub-surface current: - Low frequency – penetrates further down into the water column - Uses Doppler shift to determine speed and direction of scattering particles in the water column

MBARI Vertical Profiler (MVP) The MBARI Vertical Profiler combines the high-resolution data of a profiler with the long-term capability of a mooring for monitoring variations at the upwelling fronts Profiler was designed to sit at the bottom of the mooring tether and ascend, sampling a vertical profile every hour

Data Set and Collection Location ADCP (13SEP-27SEP) Time Pressure Depth (3m-26m) U Velocity V Velocity MVP (31AUG-27SEP) Depth (0-15m) Temperature Salinity Chlorophyll Optical Backscatter ADCP MVP

Temperature and Salinity Profiles

Chlorophyll and Optical Backscatter

U and V Velocity

Rotated ADCP Velocity Data Non Rotated Rotated (15o)

East/West Velocity (Along Shore)

North/South Velocity (Cross Shore)

Empirical Orthogonal Function (EOF) EOF analysis is a decomposition of a signal or data set in terms of orthogonal basis functions which are determined from the data EOF method finds both time series and spatial patterns The basis functions are chosen to be different from each other accounting for as much variance as possible.

East West

East West

North South

North South

Calculations Richardson Number A dimensionless number expressing the ratio of the removal of energy by buoyancy forces to its production by the shear in a flow. overall parameter describing a whole flow as opposed to the gradient and flux The critical Richardson number: Rc = 0.25 Ri < Rc = Unstable Ri > Rc = Stable Brunt-Vaisala Frequency ρ is the potential density and depends on both temperature and salinity

Density Profile

Velocity Profile

Temporal Smoothing

Richardson Number (Not Log)

Richardson Number (Log)

Met Check Date Wind m/s Wave Ht m 15SEP 005/4 999 16SEP 338/6.3 1.21 19SEP 318/8 (gst 11) 20SEP 167/3 21SEP 332/4 Wave Ht m 999 1.21 2.05 2.57 3.07 2.07 2.04 Info provided by NOAA buoy 46042 2007SEPT 1200

Graph provided by John Ryan

Graph provided by John Ryan

Conclusions Limited scope data Depths not compatible and restrictive of bottom interpretation for turbidity and sediment movement Sampling rates varied but could be overcome by data massaging Data compatible for buoyancy, shear and Richardson Number calculations Instabilities exist where upwelling is present Instability (upwelling) consist with measured increase in surface winds and wave height

Questions?

References Prof Collins Dr John Ryan, MBARI Wikipedia http://www.onr.navy.mil NOAA Marine Environmental Buoy Database Tarry Rago Tetyana Margolina http://www.whoi.edu/instruments/viewInstrument http://www.macartney.com http://www.brooke-ocean.com/mvp_main.html