Validation Test Report for the 1/16 Degree Global NRL Layered Ocean Model Nowcast/Forecast System
Abstract
This report describes validation tests for the eddy-resolving 1/16 degree global Naval Research Laboratory (NRL) Layered Ocean Model (NLOM) nowcast/forecast system. For the nonassimilative model, maps of sea surface height (SSH) and sea surface temperature (SST) show that the model depicts the observed positions of the major fronts. Comparisons of model SSH variability with altimetry and correlations with tide-gauge SSH time series demonstrate ocean model skill. In addition, model comparisons with daily buoy time series of SST indicate that the model has SST simulation skill when forced by winds and thermal forcing. The realistic nonassimilative model simulation skill indicates that the model will add skill to the data assimilation cycle and, in the case of SSH assimilation, allow the model to be used as the first-guess for the analysis. Validation tests of the assimilative model were performed. SST comparisons with unassimilated buoy time series show that the model has good agreement with the observed data. SSH comparisons with observed sea level from coastal stations and buoys indicate that the model has accurate SSH and the correlations are higher with data assimilation. Nowcast comparisons with analyzed frontal positions from the Naval Oceanographic Office show that the model can be a useful tool to help the analyst improve frontal analyses. Forecast evaluations indicate that the model has SSH predictive skill of at least 30 days in the Kuroshio Extension, about 15 days in the Gulf Stream, and at least 30 days when calculated globally. The NLOM system was also tested for improvement of the Modular Ocean Data Assimilation System (MODAS) synthetic temperature profiles by using the NLOM SSH field as opposed to the MODAS 2-D SSH analysis field. Results indicate that the synthetics from NLOM SSH are, in general, better than MODAS SSH. (2 tables, 50 figures, 34 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 14, 2003
- Accession Number
- ADA414185
Entities
People
- Alan J. Wallcraft
- Edward Joseph Metzger
- Harley E. Hurlburt
- Jay F. Shriver
- Robert C. Rhodes
Organizations
- United States Naval Research Laboratory