As more understanding was gained of the complexity and variability of the 

 ocean it became apparent that these approaches were not fully adequate 

 for operational purposes. The controlling environmental conditions have 

 to be described on a broad, synoptic basis, and even more important, pre- 

 dicted for the future. 



To develop an integrated system to observe, analyze, predict, and display 

 oceanographic conditions which apply to ASW operations, resources for 

 basic research at universities and applied research and development at Navy 

 facilities were marshaled in 1959. Techniques were developed for forecasting 

 many of the ocean's variables, and for applying these forecasts to specific 

 operational ASW problems. 



Antisubmarine Warfare Environmental Prediction 



The major effort dedicated to ocean environmental prediction in support 

 of fleet sonars is the Antisubmarine Warfare Environmental Prediction 

 Services (ASWEPS) program. Initially developed by the Naval Oceano- 

 graphic Office, ASWEPS was implemented as an operational oceanographic 

 prediction system in 1966 by the Naval Weather Service Command and has 

 since been continuously improved and expanded to provide fleetwide 

 oceanographic services. Through this system, data gathered by the fleet 

 and other sources are analyzed at oceanographic centers ashore. Charts of 

 various oceanographic parameters are then sent in real time to ASW 

 groups at sea where they are converted into sonar effectiveness information. 



More recently, computers at shore-based facilities have been used to 

 integrate oceanographic and weather data with sonar equipment factors. 

 Sonar range predictions are then calculated and transmitted directly to fleet 

 units. This has eliminated the need for transmission of some of the basic 

 charts, and reduced the need for trained environmentalists aboard ship to 

 interpret them. 



The predictive system operated by the Naval Weather Service comprises 

 a network of 33 activities that produce environmental predictions for the 

 northern hemisphere oceans. The Fleet Numerical Weather Center at 

 Monterery, Calif., is the hub of the Naval Environmental Data Network 

 which links the computer facilities used in the collection, processing and 

 dissemination of oceanographic and meteorological data and predictions. 

 Large-scale automation is currently improving and expediting the system's 

 output. 



Forecasts provided include : sea and swell ; subsurface current speed and 

 direction; sea-surface temperature patterns; mixed layer depth; vertical 

 profiles of temperature and sound velocity, sea ice conditions, optimum 

 tracks for ship routing, and special factors relating to underwater surveillance 

 programs. Various combinations of these factors are furnished as required 

 by antisubmarine warfare and other fleet operations. 



Although environmental and sonar range prediction are being used ef- 

 fectively now, continuing improvement is required. The most severe limita- 



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