Salinity and temperature in South San Francisco Bay, California, at Dumbarton Bridge: Results from the 1999-2002 water years and an overview of previous data

Salinity and temperature were measured in near-surface waters at Dumbarton Bridge in South San Francisco Bay during the 1999–2002 water years (1999WY–2002WY). The complete data set from this site, which included 1990WY–1993WY and 1995WY–1998WY, provided a time–series of observations covering a wide range of hydrologic conditions. These conditions included critically dry years and years with above-normal and near–record precipitation and discharges from the major rivers and local streams. Data collection at 15–minute intervals allowed resolution of variability associated with daily tides and other short-term phenomena. Both local stream discharges to South San Francisco Bay and Sacramento–San Joaquin River discharges to North San Francisco Bay affected salinity at Dumbarton Bridge. Salinity at Dumbarton Bridge varied with the daily tides, and the lowest salinity values (annual) coincided with precipitation and freshwater inflows usually in winter. Short–term and seasonal variations in temperature at Dumbarton Bridge typically followed changes in air temperature and solar irradiance.