Multi-scale Coupled Modeling Studies on the Northeast U.S. Continental Shelves

D. B. Haidvogel

Institute of Marine and Coastal Sciences

Rutgers University

Achieving the goals of the BASIN program will require the development, evaluation and application of multi-scale, coupled models for the North Atlantic Basin, including its circulation and accompanying ecosystems. The desirable attributes of a multi-scale numerical modeling system include: the ability to “properly” represent processes operating on basin, regional and local scales, as well as their interactions; a flexible, hybrid vertical coordinate system; non-oscillatory advection and local conservation of tracer fields; coupled sub-models for (e.g.) atmospheric forcing, ecosystems response, etc.; methods for advanced data assimilation; adaptive grid refinement; and affordable computational performance, in particular on today’s parallel computing systems. Successful approaches to these desirable design features already exist within the ocean modeling community, and we briefly review some of these alternatives.

Utilizing these novel techniques, prototype multi-scale modeling systems are being implemented within various sub-regions of the North Atlantic Basin. One example, under development for nested regions within the Northwest Atlantic, is shown in Figure 1. The scientific and technical issues being addressed with this system include coastal upwelling and associated in-water optical properties; seasonal and interannual variability in ocean carbon flux, transport and burial; air-sea heat and momentum transfer and boundary layer dynamics; transport of nutrients and contaminants in the Hudson River plume; tidal mixing and frontal exchange; and the implementation of data-assimilative regional prediction systems.

The circulation models being utilized in these efforts are the Regional Ocean Modeling System (ROMS; http://marine.rutgers.edu/po/index.php?model=roms), the Finite Volume Community Ocean Model (FVCOM; http://codfish.smast.umassd.edu/FVCOM.html), as well as the mesoscale atmospheric models MM5 and WRF. As one component of these ongoing studies, we are developing realistic simulations of shelf circulation, mesoscale events, and interannual variability associated with major climate modes such as the North Atlantic Oscillation. This will be achieved by improving the basin-scale embedding procedures to use the retrospective and operational products from the North Atlantic eddy-resolving models of the Mercator (www.mercator.com.fr) and HYCOM (hycom.rsmas.miami.edu) groups that assimilate satellite altimetry, sea surface temperature, and Argo float profiles.

Figure 1: Some of the nested domains under study within the Northwest Atlantic: (1) the Northeast North Atlantic domain, (2) the Northeast Observing System, (3) the Coupled Boundary Layer Air-Sea Transfer domain, (4) the Lagrangian Transport and Transformation Experiment, (5) the NY/NJ Bight domain, and (6) the region of the proposed Caribbean Sea prediction system.