THE PROBLEM 



Study the physical properties of sea ice to ascertain those properties which may 

 be pertinent to naval operational needs. 



RESULTS 



An initial study, in the Bering Sea, of such sea-ice properties as density, salinity, 

 air-bubble distribution, size and distribution of crystal grains, and elastic moduli, 

 was accomplished. Two sites were involved, in 1954 and 1955. 



RECOMMENDATIONS 



1. Conduct a study of the variation of all parameters over one entire ice season 

 at one location, attempting to relate the plate-wave velocity variation with the 

 state of the sea ice and the state of the sea ice with its breaking properties. 



2. Obtain heat-transfer ' information by making continuous measurements over a 

 complete ice season of (1) temperature gradients through an ice sheet with a snow 

 cover, (2) wind gradients above the ice sheet, (3) wet and dry temperature gradi- 

 ents above the ice sheet, and (4) the net radiation. 



ADMINISTRATIVE INFORMATION 



Work was done under SW-01102, NE 121217-847.1 (NEL L6-1, Part 1), by mem- 

 bers of the Special Research Division. This report covers work performed in Feb- 

 ruary and March 1954, and March and April 1955, and was approved for publi- 

 cation 11 February 1958. 



The authors are greatly indebted to the crew of the USCGC NORTHWIND for 

 assistance rendered, and particularly to the UDT and EOD groups which partici- 

 pated in the Bering Sea Expeditions in the winter of 1954 and 1955. Appreciation 

 is also expressed to all members of the Submarine and Arctic Research Branch, 

 particularly Dr. W. K. Lyon for his encouragement and technical assistance; L. L. 

 Morse for his technical assistance in the seismic instrvimentation; A. C. Walker 

 for his assistance in general instrumentation; and R. N. Rowray for his help in 

 analyzing data. 



CONTENTS 



page 



2 INTRODUCTION 



3 ELASTIC-WAVE THEORY 



5 MEASUREMENTS, WINTER 1954 BERING SEA EXPEDITION 



7 MEASUREMENTS, WINTER 1955 BERING SEA EXPEDITION 



19 SUMMARY 



23 RECOMMENDATIONS 



23 REFERENCES 



MBL/WHOt 



D3D1 DOMOSSi 



