Dispersion in the Surfzone: Tracer Dispersion Studies
Abstract
Terrestrial runoff and river input dominates urban pollutant loading rates degrading nearshore and surfzone water quality (e.g., Boehm et al., 2002). Surfzone mixing processes disperse and dilute such (and other types of) pollution. On smaller length-scales (smaller than the water depth), breaking-waves and bed-generated turbulence mix tracer. However, field surfzone observations of turbulence previously have been extremely scarce, and much about surfzone small-scale turbulence is not known. On larger scales (10 100 m), horizontal dispersion is driven by surfzone eddies and meanders associated with shear waves (Oltman-Shay et al., 1989) or finite breaking crest length (Peregrine, 1998). Understanding the small and large length-scale mixing processes important to predicting the fate (transport, dispersal, and dilution) of surfzone tracers whether pollution, bacteria, larvae, or nutrients. The scientific objective is to improve understanding and modeling of dispersion of tracers (pollution, fecal indicator bacteria, fine sediments) within the nearshore (a few 100 m of the shoreline) and the surfzone. In this report, the focus is on three research components built upon observations from the HB06 experiment (PIs: Feddersen and Guza). The first is stochastic modeling of surfzone drifter dispersion from the HB06 experiment (Spydell and Feddersen, 2011). Second, studying the small-scale turbulence in the surfzone due to breaking waves and bottom boundary layer processes (Feddersen, 2011). Third, is modeling nearshore nutrient fluxes and the resulting phytoplankton and comparing it to observations (Omand et al., 2011b). In addition, IB09 experiment (performed in collaboration with R. T. Guza) analysis is ongoing and is not described here.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2011
- Accession Number
- ADA557187
Entities
People
- Falk Feddersen
Organizations
- Scripps Institution of Oceanography