This bulletin, prepared by Dr. H. S. Chen, Mr. L. D. Burroughs, and H. L. Tolman of the Ocean Modeling Branch (OMB), Environmental Modeling Center (EMC), National Centers for Environmental Prediction (NCEP), describes automated global ocean wave guidance provided in graphic, alphanumeric, and GRIB formats. This guidance was implemented operational use in 1999.
The NOAA/WAM will be replaced with the NOAA WAVEWATCH III (NWW3). The NWW3 is a third generation model, but differs in many respects from the NOAA/WAM: it accounts for wave dispersion within a discrete spectral bin by adding diffusion terms to the propagation equation (Booij and Holthuijsen 1987); it uses the Chalikov and Belevich (1993) formulation fori wave generation and the Tolman and Chalikov (1996) formulation for wave dissipation; it employs a third order finite difference method by utilizing a split-mode scheme with a Total Variance Diminishing limiter to solve wave propagation; its computer code has been optimized to fully utilize the MPP structure of the new IBM R/S 6000 SP; it uses a higher spatial resolution (1.25o x 1.00o lon./lat. grid instead of 2.5o x 2.5o), a slightly larger domain in north-south extension (78oN - 78oS rather than 77.5oN - 67.5 oS), and a higher directional resolution (24 directions in place of 12).
The bulletins and graphics of the new guidance follow the same formats shown in TPB No. 426 (Chen, 1995), except for the following differences :
Technical Procedures Bulletin No. 426 is now operationally obsolete.
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