Quantifying the Role of Wind Field Accuracy in the U.S. Navy's Global Ocean Wave Nowcast/Forecast System

摘要

This report documents the second part of an investigation to determine the relative importance of various sources of error in the two global scale models of wind-generated surface waves used operationally by the U.S. Navy (the first part of the investigation is documented in an earlier NRL report; a short review of that earlier report is given herein). Here, we focus primarily on the impact of wind forcing (provided by an atmospheric model and/or data assimilation system) on the WAVEWATCH-III model. We use the time period of January 1-February 8, 2002 in global WAVEWATCH-III hindcasts, forced by three different types of wind analyses, one being the operational global surface wind analyses produced by Fleet Numerical Meteorology and Oceanography Center. Modeled total wave heights are compared to buoy and altimeter data (ERS-2 and TOPEX) locally, regionally, and globally. Based on these and earlier comparisons, it is credible that errors associated with wind forcing dominate the total error in the Navy's contemporary (circa January/February 2002) operational global wave model nowcast/forecast system. However, since the operational surface wind product is periodically improved, the relative magnitude of wind forcing error can be expected to change over time. (14 figures, 2 tables).