Remote sensing and forecasting of coastal exchange for battlespace awareness
Abstract
" The overall objective of the proposed research is to improve forecasts of coastal exchange for improved battlespace awareness in the nearshore environment. The work leverages a highly unique airborne remote sensing dataset from the ONR Inner Shelf DRI and complementary numerical modeling. The surf zone to inner shelf transition region (STR) is an understudied environment at the onshore boundary of the inner shelf (5-20 m depth), where rip currents eject surfzone water offshore and intersect with shelf processes including internal bores. Understanding and predicting the resulting cross-shelf material transport, including the fate of shore-released drifting mines, pollutants, toxins, sediment, bubbles, and heat, is important for amphibious vehicle operation,acoustic communication measurement systems, and optical mine hunting. Recent idealized modeling efforts and field measurements have significantly enhanced understanding of cross-shelf exchange driven by rip currents and surfzone eddies on a relatively uniform coastline. However, parameterizations of surfzone exchange have not been compared with observations on complex non-uniform coastlines, in part because it is difficult to resolve these episodic, spatially localized processes with in situ observations. In addition, wave-timescale unsteadiness and uncertain bathymetry present a significant challenge to deterministic predictions. Here, the variability of surfzone exchange on complex coastlines will be assessed using airborne remote sensing, three-dimensional wave-averaged (COAWST: ROMS, SWAN) and wave-resolving (SWASH) models, and parameterization frameworks. The approach leverages a large field campaign spanning 50-km of a complex caped coastline near Pt. Sal, CA, part of theONR Inner Shelf DRI. The PI used an internal award to lead additional flights (visible, infrared, microwave) and vessel surveys (profiles of temperature, salinity, turbidity, and velocity) targeted to quantify surface signatures of STR processes. The models COAWST and SWASH will be tested using the observations, and model results will be used to develop parameterizations of coastalexchange. A coastal exchange index will be developed to indicate ejections of mines, turbidity, and pollutants. This can be employed as a tactical aid similar to the modified surf index. The specific objectives are: 1. Map probability distributions of the fate and origins of nearshore drifting objects and tracers for (a) variable wave-driven hydrodynamics and (b) uncertain bathymetry2. Develop a coastal exchange index to forecast surfzone ejections of objects and tracers for improved nearshore battlespace awareness The primary expected result of this work is improved remote sensing and forecasts of drifting object trajectories and inner-shelf conditions to support Naval operations in denied areas. This work will use a unique airborne remote sensing dataset and numerical modeling to characterize the spatial and temporal variability of surfzone ejections, leading to new parameterizations inregional models."
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 17, 2020
- Source ID
- N000142012543
Entities
People
- Melissa Moulton
Organizations
- Office of Naval Research
- United States Navy
- University of Washington