through interconnected digital computers and on-line 

 communications equipment. FNWC processes, disseminates, and 

 displays meteorological and oceanographic analyses and forecasts 

 on a hemispheric basis to meet defense needs. With these facilities, 

 realtime products are continually updated and tailored to fleet and 

 other defense requirements. The FNWC products are distributed 

 through the NEDN to Fleet Weather Centrals and Facilities 

 strategically located throughout the world. Marine predictions are 

 tailored to the special needs of the users, with much of the specific 

 Navy support classified because of its application; however, a large 

 part of the data collection program and data processing techniques 

 contributes to civil needs. Routine services include wave, swell, and 

 surf forecasts for fleet operations; warnings of significant 

 atmospheric and oceanic conditions for ships at sea and in port and 

 for shore-defense installations; ice condition forecasts for military 

 operations; prediction for pollution abatement or control, search and 

 rescue, and aircraft ditching; and complete point-to-point forecasts 

 like those for the optimum track ship routing (OTSR) program. Most 

 prediction products, however, are concerned with the ocean 

 characteristics that affect the transmission of acoustic energy and 

 are tailored to specific weapon systems. 



The introduction of the wave spectra concept some years ago 

 resulted in an important advance in the understanding of the random 

 motions of the ocean surface and in man's ability to predict these 

 random motions. Limited computer capacity and the difficulty in 

 applying these data have resulted in a lag in the adoption of 

 operational wave spectra prediction programs. In FY '73 the Navy 

 evaluated an operational wave spectral forecasting program 

 (Pierson-Moskowitz (PM] model] for the Mediterranean and 

 achieved results comparable to the singular wave prediction 

 program, but with the option of greatly increased detail. Present 

 plans call for the introduction and evaluation of the Barnet model for 

 the Mediterranean with increased detail in the higher frequencies 

 and anticipated greater accuracy. An improved PM wave-spectra 

 model has been put into use in the Pacific. Forecasts to 48 hours are 

 made twice daily. This Pacific program will be evaluated in FY '74 

 and FY '75. Recently the same improved model was adopted on a trial 

 basis for the North Atlantic. It is^ intended that the Barnet model be 

 programed in FY '74 for the entire Northern Hemisphere, and 

 evaluations of both models will be made. Wave spectra have direct 

 application to ship motion and to ship structure, and therefore offer 

 the potential for improving OTSR programs. Additionally the 

 climatological file of wave spectra and wave-spectra predictions 

 resulting from these new prediction programs can assist in solving 

 other ocean-wave-related problems. 



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