Ocean Forecast and Analysis Models for Coastal Observatories

Abstract

Physical circulation processes in the coastal ocean affect air-sea interaction, sediment transport, the dispersal of nutrients and pollutants from terrestrial sources, and shelf-wide ecosystem dynamics and carbon cycling. A burgeoning network of coastal ocean observatories is expanding our ability to study these processes by simultaneously observing coastal ocean physics, meteorology, geochemistry and ecology at resolutions suited to quantitative interdisciplinary analysis. Complementary developments in ocean modeling have introduced more accurate numerical algorithms, improved parameterizations of unresolved sub-grid-scale mixing and boundary layer processes, and a transition to higher resolution on parallel computing platforms. The formulation and capabilities of modern coastal models are illustrated here with two examples from applications in the Mid-Atlantic Bight region of the northeast U.S. continental shelf. These are the Coupled Boundary Layers and Air-Sea Transfer (CBLAST) program centered on the Martha’s Vineyard Coastal Observatory, and the Lagrangian Transport and Transformation Experiment (LATTE) centered on the Hudson River plume. The studies utilize the Regional Ocean Modeling System (ROMS) as a forecast tool to assist in the deployment of moveable instrumentation, and as a synthesis tool to aid the interpretation of observations. It is shown that regional models have the resolution and accuracy to capture the dominant features of the coastal ocean heat and salinity budget on diurnal to weekly time scales in regions with strong tides, vertical stratification, and highly variable bathymetry.