The Hyperspectral Signatures Of Complex Ocean Frontal Boundaries: The Example Of Cold Air Outbreaks In The Northern Gulf Of Mexico

Boreal winter meteorological fronts manifest across the northern Gulf of Mexico as rapid 10-15 degrees C drops in air temperature and accelerating northerly winds. The physical coastal ocean response across the Louisiana-Texas (LATEX) continental shelf system involves a complex interplay between coastal buoyancy, wind forcing, and intense thermal energy fluxes out of the ocean. Herein we combine numerical simulations, in situ optical surveys, and coincident satellite images derived from the Ocean and Land Colour Imager (OLCI) and other sensors to further unravel the mechanistic functioning and optical signatures of these complex events. The conspicuous optical gradients evident in color satellite images coincident with cold air outbreak (CAO) events appear to result from surface ventilation of sediment-laden bottom waters and wind/buoyancy-driven surface currents. The hyperspectral gradients associated with water mass types (sediment resuspension in marine waters versus freshwater effluent plumes) give rise to true color gradients that may be tracked with low spectral resolution color sensors at very high temporal resolution.