Validation datasets for coupled regional atmosphere/ocean models

There are at present within the field of ocean general circulation modeling four classes of numerical models which have achieved a significant level of community management and involvement, including shared community development, regular user interaction, and ready availability of software and documentation via the World Wide Web. These four classes are loosely characterized by their respective approaches to spatial discretization (finite difference, finite element, finite volume) and vertical coordinate treatment (geopotential, isopycnic, sigma, hybrid). Given the rapidly growing number of models, and their algorithmic options, it is necessary that we understand the relative behavior of these models and their component methods. Several alternative approaches to model characterization are possible. One of these, based upon an inexpensive set of process-oriented test problems, is the basis for an ocean model test problem web site recently created by the authors (http://marine.rutgers.edu/po/tests).

Another possibility is the assembly of a parallel suite of model test problems based on intensive geophysical datasets - e.g., as collected in the New York Bight at the LEO-15 National Littoral Laboratory. As of summer 1999, the modeling infrastructure at LEO-15 utilized the latest version of our coupled regional ocean/atmosphere model (ROAMS), whose combined components include a high-resolution regional ocean circulation model and a nested mesoscale meteorological model run at 4 km local resolution. Physical processes addressed at LEO-15 include frontal development, air-sea coupling, the effects of stratification and topography, and vertical mixing in the coastal ocean.

We describe progress in creating a high-resolution coastal prediction skill assessment database derived from the real-time activities at LEO-15 during the summer of 2000. The goal is to provide a uniformly gridded, high-quality suite of initialization, surface forcing, and verification data with which to assess and to compare alternative coupled atmosphere/ocean circulation models, including approaches to data assimilation. Examples of forecasts from the ROAMS model are provided as an example of current forecasting capabilities.