Publication
Data-Driven, Multi-Model Workflow Suggests Strong Influence from Hurricanes on the Generation of Turbidity Currents in the Gulf of Mexico
Publisher:
MDPI AG
Date:
06-08-2020
DOI:
10.3390/JMSE8080586
Abstract: Turbidity currents deliver sediment rapidly from the continental shelf to the slope and beyond and can be triggered by processes such as shelf resuspension during oceanic storms mass failure of slope deposits due to sediment- and wave-pressure loadings and localized events that grow into sustained currents via self- lifying ignition. Because these operate over multiple spatial and temporal scales, ranging from the eddy-scale to continental-scale coupled numerical models that represent the full transport pathway have proved elusive though in idual models have been developed to describe each of these processes. Toward a more holistic tool, a numerical workflow was developed to address pathways for sediment routing from terrestrial and coastal sources, across the continental shelf and ultimately down continental slope canyons of the northern Gulf of Mexico, where offshore infrastructure is susceptible to damage by turbidity currents. Workflow components included: (1) a calibrated simulator for fluvial discharge (Water Balance Model - Sediment WBMsed) (2) domain grids for seabed sediment textures (dbSEABED) bathymetry, and channelization (3) a simulator for ocean dynamics and resuspension (the Regional Ocean Modeling System ROMS) (4) A simulator (HurriSlip) of seafloor failure and flow ignition and (5) A Reynolds-averaged Navier–Stokes (RANS) turbidity current model (TURBINS). Model simulations explored physical oceanic conditions that might generate turbidity currents, and allowed the workflow to be tested for a year that included two hurricanes. Results showed that extreme storms were especially effective at delivering sediment from coastal source areas to the deep sea, at timescales that ranged from in idual wave events (~hours), to the settling lag of fine sediment (~days).