Comparison Between Third- and Second-Generation Ocean Wave Models
Abstract
The objective of this study is to assess the relative performance of a second-generation (2G) model, WISWAVE, and a third-generation (3G) model, WAM, in deep water. High-quality wind fields, with detailed spatial and temporal resolution, were used to force both models in an effort to isolate differences between their formulations. Even though previous studies have compared these models, this study is the first direct comparison where frequencies and directions have been discretized identically; no wind field interpolation was used, and wave model grids are not nested. Five extratropical storm events that occurred along the U.S. Atlantic coast were selected for comparison. All five historical wind fields were developed using kinematic analysis and objective techniques. These storm events were selected because of the availability of high-quality winds and their variety of conditions ranging from extreme events to more moderate and variable events characterized by sea and swell, shifting winds, and passage of cold fronts. Three of the storms occurred during the Surface Wave Dynamics Experiment (SWADE) intensive operation periods (IOP) and are IOP1, IOP2, and IOP3. The remaining two storms, the "Halloween Storm" and the "Storm of the Century," were significant events causing flooding and damage along the Atlantic seaboard. Each model was driven by identical wind fields and gridded to 1/2 deg latitude and longitude spatial resolution and 1-hr temporal resolution. Both models were run in the deepwater mode. Model results for these storms were compared with National Data Buoy Center (NDBC) buoy wave measurements. The analysis of the results is divided into three steps. First, a qualitative comparison is made between model predictions and buoy data for the mean parameters: significant wave height, mean wave period, peak wave period, peak wave direction, directional spreading coefficient, wind speed, and wind direction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1998
- Accession Number
- ADA353603
Entities
People
- Steven M. Bratos