PREDICTION AND SURVEY 91 



somewhat similar, but extremely different, environments— the air-sea inter- 

 face—is the subject of extensive investigation. The Navy is studying me- 

 teorological prediction methods and ocean-atmosphere conditions affect- 

 ing missile launch restrictions, aircraft and ship route forecasting, hurricane 

 prediction, polar weather techniques, and radio/radar propagations over 

 water. Hardware developments are being made incident to sensing, record- 

 ing, and telemetering observations of atmospheric and related oceanic 

 parameters. This increased knowledge of the interactions between sea and 

 atmosphere will be of benefit to mariners everywhere. 



MAGNETICS AND GRAVITY 



Two general areas of great interest to the Navy, in such applications as 

 undersea navigation and ocean surveillance, are the earth's gravity and mag- 

 netic field. Developments are directed toward techniques that improve the 

 measurement, analysis, and display of the earth's magnetic field. The 

 accuracy of the spherical harmonic surface at sea level has been verified 

 from the data incorporated in the 1965 World Variation Charts. Spatial 

 coherence of short-period variations in the magnetic field is being tested by 

 simultaneous records made at two or more stations. Finally, a geological 

 interpretation of the total magnetic field data of the U. S. East Coast Sur- 

 vey is underway in cooperation with the U. S. Geological Survey. 



In response to Department of Defense requirements, The Navy is de- 

 veloping improved methods for measuring, analyzing, and utilizing the 

 earth's magnetic field. Among its objectives are to utilize magnetic field 

 characteristics to position aircraft, ships, and submarines, and to analyze 

 magnetic anomaly effects on bombing and navigation devices. Future plans 

 include preparation of detailed magnetic variation charts, which will assist 

 navigators everywhere, both surface and aircraft. The present Project 

 Magnet airborne survey system will eventually be expanded to an air- 

 borne geophysical survey system capable of providing precise, accurately 

 positioned magnetic measurements in any area of the world. 



The Navy has been assigned management control of the Department of 

 Defense project for development of a hehcopter gravity-collection system. 

 Test equipment has been selected, and the test, plans for which are well 

 underway, will be carried out jointly by the Army, Air Force, and Navy. 

 In response to this task, the Naval Oceanographic Office has plans for a 



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