Observing fortnightly variability of San Francisco Bay turbid plume from MODIS imagery

San Francisco Bay is the largest estuary on the US west coast, located on the north central coast of California. It receives water from the Sacramento-San Joaquin river system, which drains approximately 40% of the California area. Discharge magnitudes are highly variable, ranging between 100-300 m3/s during summer and fall, and between 1,000-10,000 m3/s during winter and early spring. The tides are mixed semi-diurnal with 1.3 meters of average tidal range, and presents spring-neap variability. As changes in tidal amplitude affect mixing and estuarine hydrodynamics, as well as sediment resuspension and transport, it is expected that river plume dynamics and optical water properties will also be impacted. Using a time series of daily ocean color data from 2002-2019 obtained by the Moderate Resolution Imaging Spectroradiometer (MODIS), we investigate the potential changes in size and turbidity of San Francisco Bay plume as a result of changes in tidal amplitude modulated by the fortnightly cycle, and whether these changes can be detected under the complex influence of variable discharge and wind-forcing.