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Recent Field Work - San Francisco Bay
Hydrodynamic Project
Purpose:
On October 15-16, 1997, the San Francisco Bay hydrodynamics
group conducted a 25-hour study at a site located south of the
Dumbarton Bridge in South San Francisco Bay. A subsequent deployment
just north of the San Mateo Bridge was conducted between January 22,
1998 and January 27 1998. These studies were designed to:
1. Test the potential of using acoustic backscatter intensities measured
by Acoustic Dopler Current Profiler (ADCP) for estimates of total
suspended solids (TSS) concentration.
2. Compare two methods of calibrating optical backscatter for TSS measurements.
3. Compare two, very high resolution modes of operating the
Broadband ADCPs for making high frequency (turbulence) measurements of velocity.
4. Evaluate a Laser In Situ Scattering and Transmissiometry (LISST) instrument
designed to obtain particle size distribution.
Participants during the October 15-16 study: left to right. Scott Conrad
(R/V Polaris engineer), Ralph Cheng (Project Chief), Chad English, P.F. Wang,
Jeff Gartner, Charlie Ling, Byron Richards (R/V Polaris Captain), Richard
Smith, and Francis Parchaso (not shown - Nice photo Francis!).
Rich Smith, Charlie Ling, and Jeff Gartner are shown conducting final
preparations of the ADCPs, CTDs, OBSs, and the LISST prior to the January
22, 1998 deployment just north of the San Mateo Bridge in South San Francisco
Bay. The LISST instrument is attached near the two ADCPs.
Preliminary results from recent field studies show that:
1. During some tidal conditions (near slack water) and at some locations
in San Francisco Bay, the mean particle size of suspended material may be
too small to accurately predict total suspended solids material using
backscatter intensity from the 1200kHz ADCP.
2. High resolution Mode 5 (with its lower velocity measurement standard
deviation) may be more appropriate for use in San Francisco Bay during
high frequency measurements for turbulence studies.
3. The LISST has recorded two data sets of suspended particle size distribution,
however questions remain as to the correct calibration procedures.
For more details about our recent field work please see:
The URL of this page is http://sfports.wr.usgs.gov/~gartner/field1.html
Last modified: 24 March, 1998 by Jeff Gartner
