Short-term sediment dynamics in Tampa Bay estuary: observations from a coastal oceanographic tower and satellite remote sensing

Zhiqiang Chen, College of Marine Science, University of South Florida, zchen@marine.usf.edu (Presenting)
Chuanmin Hu, College of Marine Science, University of South Florida, hu@marine.usf.edu
Frank Muller-Karger, School for Marine Science and Technology, University Massachusetts Dartmouth, fmullerkarger@umassd.edu

Short-term sediment dynamics in Tampa Bay were examined with data collected from optical, oceanographic, and meteorological sensors mounted on a coastal oceanographic tower and satellite remote sensing from 08 December 2004 to 17 January 2005. High frequency (hourly) and continuously measured backscattering coefficient at 532 nm (bbp(532)) showed large fluctuations ranged from 0.03 and 0.20 m-1 at dominated semidiurnal and diurnal frequencies. Three sediment resuspension events were also observed, caused primarily by winds (e.g. when hourly averaged wind speed >8.0 m s-1). These wind-induced waves could resuspend sediment when the estimated bottom shear stress was greater than ~ 0.2 Pa at the study site. Once suspended, sediments remained in the water column for 2-3 days after a wind event. MODIS full resolution showed that sediment resuspension primarily occurred in the lower Tampa Bay only, with less resuspension in the upper Bay during the study period. Furthermore, the twice per day images attainable from Terra and Aqua clearly showed the tidal transport of sediment from the West Florida Shelf to the lower Tampa Bay during a resuspension event. Lastly, MODIS images clearly revealed that except for local winds, remotely forced swells can also resuspend sediment but with limited spatial extent. The results indicate that the combination of high frequency in situ sensed with synoptic remotely sensed data would greatly improve our understanding of the sediment dynamics in a shallow estuary like Tampa Bay.