FOREWORD 



The increasing importance of defense installations in 

 northern areas has greatly increased the responsibilities of 

 the U.S. Navy in .supplying bases in Arctic waters, where sea 

 ice is often an operating obstacle. The Hydrographic Office 

 is charged with the responsibility of developing and testing 

 techniques for observing and forecasting sea ice conditions. 

 Standardized techniques for observing, charting, and reporting 

 sea ice are now in operational use by the Navy, as described 

 in publications issued by the Hydrographic Office. Heretofore, 

 techniques for forecasting the formation, growth, and movement 

 of sea ice have not been published by this Office. This publi- 

 cation describes in detail the factors affecting ice formation 

 and growth. 



It is requested that activities receiving this publication 

 forward their comments to the Hydrographic Office. 



iuL^****-- — 



J. B. COCHRAN 

 Captain, U.S. Navy 

 Hydrograph er 



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