I. INTRODUCTION 



A, P\irpose 



Operation DEEP FREEZE II (1956-1957), the third consecutive 

 U. S, Navy expedition to penetrate the Antarctic within as many- 

 years, transported scientific personnel and equipment to man bases 

 of the U. S. National Committee for the International Geophysical 

 Year. In addition, several secondary bases were established; 

 ELLSWORTH STATION on the Filchner Shelf, WILKES STATION on the Budd 

 Coast, ADARE STATION on Cape Hallett, BIRD STATION in Marie Byrd Land, 

 and the AMUNDSEN-SCOTT STATION at the South Pole. Many of the 

 secondary scientific projects initiated during, the 1954-1955 and 

 DEEP FREEZE I expeditions were continued. Personnel from the U. S. 

 Navy Hydrographic Office collected oceanographic and hydrographic 

 information whenever the primary objectives of the operation per- 

 mitted. 



B. Summary of Operations 



The oceanographic and hydrographic data collection programs under- 

 taken during DEEP FREEZE II operations were conducted aboard four 

 icebreakers, USS GLACIER (AGB-/,), USS STATEN ISLAND (AGB-5), USS ATKA 

 (AGB-3), and USCGC NORTHWIND (WAGB-282) (Fig. 1). This program included 

 oceanographic stations using reversing thermometers and Nansen bottles, 

 bathythermograph observations (BT's), meteorological observations, 

 ice observations, bottom sampling, transparency and water color read- 

 ings, continuous temperature recordings, biological collections, and 

 oceanic so\mdings. 



A total of 50 oceanographic stations was obtained; 26 in the Weddell 

 Sea area, 14 in the Ross Sea area, 4 off Vifilkes Coast Land, 5 off the 

 west coast of South America, and 1 near New Zealand, Dissolved oxygen 

 analyses were scheduled for all ships and all water samples. Unfor- 

 timately, pollution of one of the reagents caused drifting and exces- 

 sively high standardization runs, and thus, the absolute values are 

 erroneous to varying degrees o Nevertheless, the data are of some 

 value in that results are valid from a relative viewpoint and show 

 depths of maximum and minimum values. All of these data are tabulated 

 in Annex A, 



Bathythermograph lowerings, with the 900-foot instrument, were 

 scheduled on an hourly basis on the four icebreakers, and on a once- 

 a-watch (four-hour) basis on certain ships of the Task Force, the 

 ARNEB, WYANDOT, and BROUGH, Eqxiipment failure, weather conditions, 

 shortage of personnel, and presence of ice all tended to reduce the 

 number of lowerings accomplished, but in areas of particular interest, 

 such as the Antarctic Convergence Zone, the rate of lowerings was 

 increased. The total nianber of bathythermograph records obtained 

 aboard the icebreakers was 1595 slides by the GLACIER, 721 by the 



