Modeling and Analysis of RIVET-1 and IB09 Experiments: Inlet/ocean and Surfzone/Inner-shelf Exchange
Abstract
The exchange of tracer (temperature, salinity, contaminants, pathogens, sediment, nutrients, or larvae) between distinct nearshore geographical and dynamic regimes such as a tidal inlet and the ocean or the surfzone and the inner-shelf is poorly understood. For example, the tidal forcing dominates within the inlet whereas just outside the inlet wind, wave, buoyancy, and rotation processes become more important. Similarly, breaking-wave driven surfzone processes are radically different from the wind, buoyancy, and rotation driven processes in the inner-shelf. The interface of these regimes is important to Navy operations, yet neglect of the dynamical difference across these regions, particularly stratification, can lead to significant errors in quantifying the magnitude and mechanisms of exchange. I led two recent dye tracer release experiments: a surfzone/inner-shelf experiment (IB09, Fall 2009, Imperial Beach CA) and a tidal-inlet/surfzone/inner-shelf experiment (RIVET-I, Spring 2012, New River Inlet NC). Both IB09 and RIVET experiments had significant dye, temperature, wave, and current observations, spanning remote-sensed and in situ, for comparison against models. Each experiment provides different insight into nearshore exchange processes. Stratification plays a major role in the exchange across dynamical boundaries such as inlet/ ocean or surfzone/inner-shelf. Building upon our current analyses, the extensive surfzone/innershelf IB09 and inlet/ocean RIVET-I observations will be used in conjunction with coupled numerical models to improve our understanding of exchange across these distinct dynamical regions. This will be performed by combining remote-sensed observations, in situ observations, and simulations of tracer exchange, using coupled models (funwaveC/ROMS/SWAN) that include all the potentially relevant physics. In particular, we will 1. Perform coupled model simulations of surfzone and stratified inner-shelf temperature and dye from the IB09 field experiment. Subsequent model-data comparison and analysis will allow for new understanding regarding the mechanisms (rip currents, internal waves, Stokesdrift exchange), length-scales, and time-scales of tracer and stratification evolution onto the inner-shelf. 2. Perform model-data comparison & analysis for inlet dye releases with negligible wind and waves but strong stratification. This will lead to insight into how does material dispersion occurs between a tidal inlet and a stratified open ocean. This will push the existing model parameterization for vertical and lateral mixing to its limits, something which has not been tested before, and lead to insights regarding lateral and vertical tracer dispersal. The result of this new modeling of existing field observations and analysis will provide an improved understanding of the exchange across these distinct dynamical regions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512117
Entities
People
- Falk Feddersen
Organizations
- Office of Naval Research
- United States Navy
- University of California, San Diego