HR: 0800h
AN: OS21A-07    [Abstracts]
TI: In-Situ Water Quality Monitoring in South San Francisco Bay: Data Validation and Interpretation
AU: * Craig, M
EM: mitchell.craig@csueastbay.edu
AF: California State University, East Bay, 25800 Carlos Bee Blvd., Hayward, CA 94542, United States
AU: Schemel, L
EM: lschemel@usgs.gov
AF: United States Geological Survey, 345 Middlefield Rd. , Menlo Park, CA 94025, United States
AU: Dare, C
EM: carlindare@hotmail.com
AF: California State University, East Bay, 25800 Carlos Bee Blvd., Hayward, CA 94542, United States
AU: Yang, D
EM: david.yang@csueastbay.edu
AF: California State University, East Bay, 25800 Carlos Bee Blvd., Hayward, CA 94542, United States
AU: Brafman, R
EM: rbrafman@comcast.net
AF: California State University, East Bay, 25800 Carlos Bee Blvd., Hayward, CA 94542, United States
AU: Andrews, J
EM: joy.andrews@csueastbay.edu
AF: California State University, East Bay, 25800 Carlos Bee Blvd., Hayward, CA 94542, United States
AB: We monitored water quality from 2005 to 2007 in South San Francisco Bay using in-situ sondes that recorded time-series records of temperature, salinity, tidal depth, turbidity, and chlorophyll fluorescence. A vertical array of two sondes was used at Dumbarton Bridge, one sonde near water bottom, at 5 m mean water depth, and the other near the surface. An additional sonde was located at San Leandro. In order to validate sonde salinity data, we conducted laboratory analysis of 36 water samples collected at the locations over a 14 month period. Salinity values measured in the laboratory were in excellent agreement with data from the sondes at the corresponding times. High rainfall storms in winter 2005-2006 caused a remarkable decrease in salinity over a two-week period, and high turbidity values for nearly a week. Additional episodes of high rainfall and runoff continued into Spring 2006, producing unusually low salinity levels. Using data from the two-sonde array at Dumbarton Bridge, we identified periods of thermal stratification and destratification of several days in duration that appear to be induced by tidal mixing. We observed episodes of thermal stratification during low-energy neap tides, and destratification during high-energy spring tides. Salinity stratification appeared to be more persistent than thermal stratification, and less subject to tidal influence. We conducted periodogram analysis of time-series data. At Dumbarton Bridge, narrow high-amplitude peaks in spectral density occurred at periods of 12 and 24 hours for most parameters logged, reflecting the strong overprint of semidiurnal tides on physical processes there. At San Leandro, limited tidal circulation was reflected in the periodograms of many parameters by diffuse low-amplitude peaks at tidal periods.
UR: http:www.sci.csueastbay.edu/cicore
DE: 4217 Coastal processes
DE: 4227 Diurnal, seasonal, and annual cycles (0438)
DE: 4235 Estuarine processes (0442)
DE: 4262 Ocean observing systems
DE: 4277 Time series experiments (1872, 3270, 4475)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly