INTRODUCTION 



The appearance of this publication completes the series of United 

 States Coast Guard Bulletin 19/ 



The report is based on the observations of the Marion expedition, 

 1928, and amplified by the cruises of the General Greene to the 

 Labrador Sea, 1931 ancl 1933 to 1935. In view of the similarity and 

 intermixture between the waters north of Newfoundland and those 

 around the Grand Banks, it has been deemed advisable to add an 

 exposition of the latter based upon the researches of the International 

 Ice Patrol, the observations of which are published in Coast Guard 

 Bulletins 1-25. 



The Coast Guard's material consists of temperature and salinity 

 observations from surface and subsurface; the treatment centering 

 on a portrayal of the distribution and correlation of these two physi- 

 cal characteristics and their dependent variables in vertical and hori- 

 zontal planes. A few oxygen observations have also been made in 

 order to examine the vertical motion in the deeper water of the 

 Labrador Sea. 



The prevailing circulation, as indicated by the dynamic topogra- 

 phic maps, the velocity profiles, and the velocities of the currents 

 have been computed in accordance with generally accepted methods 

 of present-day dynamic oceanography. Calculations of the volumes 

 of the discharge, the cooling and warming eifect of given w^ater 

 masses, and other influences have been recorded. The repetition of 

 observations in many places, moreover, during a series of months 

 and a series of years, affords opportunity to discuss variations and 

 cycles. In this respect the Grand Banks region has been investi- 

 gated in more detail than has the area north of Newfoundland, but 

 even from the Grand Banks there are insufficient observations to de- 

 scribe accurately the annual cycle. 



The three collaborators have been at one time or another asso- 

 ciated with, or in active charge of, the scientific work which the 

 United States Coast Guard has maintained in connection with the 

 International Ice Observation and Ice Patrol. - 



Acknowledgments 



The Commandant of the United States Coast Guard, as chair- 

 man of the International Ice Patrol Board, as well as the other 

 members, has through an appreciation of the scientific aspects of the 

 ice-patrol work, afforded us the time to prepare this bulletin. 



The appearance of the report is largely due to the efforts of Prof. 

 Henry B. Bigelow, director, Woods Hole Oceanographic Institution. 

 We wish to take this opportunity to acknowledge particularly Dr. 



1 Contribution No. 107 of the Woods Hole Oceanographic Institution. 

 = Tho.se interested in a description of tlie metliods employed to protect Iniiis-Atlantic 

 shipping from the ice menace are referred to Smith (1931). 



V 



