conditions for ships at sea and in port, and for defense shore installations; 

 ice condition forecasts for military operations ; prediction for jxjllution abate- 

 ment or control, search and rescue, and aircraft ditching ; and point-to-point 

 total forecasts such as the Optimum Track Ship Routing program. Most 

 prediction products, however, are concerned with the ocean characteristics 

 which affect the transmission of acoustic energy and are tailored to specific 

 weapon systems. 



During 1971, the fleet evaluated ,ne newly developed Automated Ship- 

 board Forecasting System (ASFS) aboard three ASW carrier-group flag 

 ships. The ASFS produces computer-developed displays of environmental 

 data and sonar performance indexes tailored to specific weapon systems for a 

 localized climatic ocean model stored in the computer and modified by real- 

 rime observations from Task Group Ships. Major emphasis is being placed on 

 the refinement of prediction methods and the development of local models 

 for the many specific geographic areas of operational interest and on the 

 integration of the system into the multipurpose computer system being de- 

 signed for the new aircraft carriers. 



Publication of 16 more volumes in a series of detailed marine data climatic 

 summaries extended coverage to parts of the coastal areas of the Pacific and 

 Indian Oceans. Computer programs were developed for the automatic in- 

 troduction of satellite data into sea-surface temperature forecasts, and several 

 operationally new physical models for forecasting underwater sound param- 

 eters were introduced. Wave and swell computer analysis was improved 

 through the introduction of significant changes in the operational Northern 

 Hemisphere Wave Program. 



Ocean Science 



The Navy Ocean Science Program consists of a broad spectrum of physical, 

 chemical, biological, and geological oceanographic studies in support of 

 military requirements. It ranges from the contract research program of the 

 Office of Naval Research, which by its basic nature holds major civil benefits, 

 to the investigation of the propagation of acoustic energy in the ocean 

 medium. Much of this effort applies almost exclusively to national security 

 needs and is classified. Even here, however, supporting nonacoustic environ- 

 mental data collected are normally unclassified and are made available to the 

 general ocean community. 



Within the ocean, sound remains the only practical means of transmitting 

 or receiving information beyond a few hundred feet. Transmission-loss re- 

 search and development is concerned with the identification and evaluation 

 of the many paths by which sound can travel from a source to a receiver in 

 the sea. A combined theoretical and experimental program is underway to 

 further understanding of these paths through experiments at sea and com- 

 puter simulations. 



Several numerical models are required because Navy sonar systems en- 

 compass a broad spectrum of frequencies and ranges. One of the most diffi- 

 cult aspects of nature to simulate with a computer, and one of the most im- 

 portant to both active and passive systems, is the interaction of the traveling 

 sound wave and the bottom. Extensive measurements have been made by 



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