Implementation of WAVEWATCH III at Fleet Numerical Meteorology and Oceanography Center

Fleet Numerical Meteorology and Oceanography Center (FNMOC) Is in the process of transitioning its operational models suite from a Cray C90 shared memory architecture to SGI Origin 2000 (O2K) and Origin 3000 (O3K) distributed memory systems. As part of this transition, the third generation WAVEWATCH III (WW3) wave model is currently being implemented to replace the third generation Wave Model (WAM). WW3 offers several advantages over WAM. For example, WW3 has a third-order accurate wave propagation scheme that reduces the numerical diffusion of swell energy characteristic of the first-order scheme used In WAM. Also, WW3 has been programmed to run efficiently on distributed memory computers. The global Implementation of WW3 was ported to the O2K in December 2000, with atmospheric forcing provided by the FNMOC Navy Operational Global Atmospheric Prediction System (NOGAPS) model. Regional versions of WW3 have also been implemented on the O3K computer in six areas of naval Interest. The wave models were run in parallel two months and the results are compared to wave height measurements. WW3 became operational at FNMOC, replacing WAM, In August of 2001.