Hydrodynamics and Marine Optics during Cold Fronts at Santa Rosa Island, Florida

Abstract

Keen, T.R. and Stavn, R.H., 2012. Hydrodynamics and marine optics during cold fronts at Santa Rosa Island, Florida. Observations of optical and hydrodynamic processes were made on the open beach on Santa Rosa Island, Florida, in March 1995. This study focuses on the passage of two cold fronts. The observations have been supplemented by a bio-optical model; a suite of hydrodynamic models to simulate coastal flows forced by waves, tides, local wind, and coastal sea level; and a geo-optical model that predicts scattering by mineral particles resuspended by wave action. These models have been used to examine the interaction of atmospheric forcing and hydrodynamics with respect to the observed marine hydrosol. The optical and hydrodynamic measurements, and the model results, have been used to conceive a cold-front regime model of the hydrosol for open beaches in the Gulf of Mexico. The optical environment during the cold front was determined by three hydrosol phases: (1) a prefrontal steady-state hydrosol consisting of fine resuspended mineral particles, phytoplankton cells, organic detritus, and colored dissolved organic matter; (2) a frontal phase dominated by resuspended mineral particles; and (3) a postfrontal hydrosol containing large phytoplankton, detritus, and fine mineral particles. This concept is useful for identifying the physical processes responsible for observed optical properties. It should be applicable to other regions and types of events.