Surface Freshwater Plumes Contributing to the Formation of the Barrier Layer and Salinity Fronts
[28-Nov-2014] Soloviev, A., Matt, S., and Fujimura, A.
Presented at the 2014 Ocean Salinity Science and Salinity Remote Sensing Workshop
Surface freshwater plumes contributing to the formation of the barrier layer and salinity fronts Some areas of the World Ocean are characterized by substantial influx of freshwater. Localized rain and river runoff may produce relatively shallow, near-surface freshwater plumes. Due to buoyancy forces, these plumes have a tendency to spread in the horizontal direction. These buoyancy-driven flows are a type of the organized structure resembling a classical gravity current. Buoyancy-driven surface currents are an important component of the oceanic environment, leading to water mass exchange by horizontal advection and enhanced vertical mixing. The freshwater plumes can be linked to larger scale features such as the barrier layer and fronts, contributing to the salinity field in the Aquarius and SMOS footprints. The dynamics of freshwater plumes are inherently three-dimensional. We have applied a computational fluid dynamics (CFD) model to study the structure and dynamics of low-density near-surface plumes. Our fully three-dimensional, non-hydrostatic CFD model is able to reproduce in detail the near-surface propagation as well as the interaction between surface gravity current, ambient stratification, and wind stress. The modeling results are being compared with available observational data from the tropical oceans and from coastal areas with large river runoff.