DISCUSSION OF PROFILES 1-15. 



Lieut. Edward H. Smith, U. S. Coast Guard. 



PROFILE NO. 1— STATIONS 247-252. 



This section rims from the east slope of the Grand Banks ofishore 

 into the Atlantic Basin. It was occupied April 9-11, except station 

 247. which was occupied March 31. The chief interest in this par- 

 ticular subsurface examination centers on the possible factors in- 

 volved in the wide offshore movement of the early season icebergs. 

 (See p. 70.) 



Salinity. — A floating pool of saline water >35 %o, 100 meters 

 thick and 110 miles wide, lay on the surface at the mid stations, 

 250-248, and is the most noteworthy feature shown on the profile. 

 Such a phenomenon has been observed in this locality before. 

 (See Treasury Bull. No. 10, p. 88.) On approaching the slope the 

 water became fresher, while at the outer station, 247, salinities lower 

 than 34.5 %o are also to be noted in the upper 150 meters (82 

 fathoms) and again at the 450-meter (246 fathoms) depth on the 

 profile. , y 



Temperature ■ — -The isolated body, of salty water mentioned above 

 at the intermediate stations, registered over 10° in temperature, 

 which was warmer than the water on either side of it. Icy cold 

 water, — 1.7°, lay on the slope to a depth of 150 meters (82 fathoms), 

 below which it warmed with increasing depth to 3.8° at 450 meters 

 (246 fathoms). Such low temperature, — 1.7°,. and the drift of bergs 

 as shown by charts "F" and ''G," indentifies this as Labrador 

 Current, which was flowing parallel with the east side of the Grand 

 Bank at this time. At the outer station, 247, we found water not 

 so cold as that on the slope, but colder than that directly inshore of 

 it. Although the temperature and salinity were higher than water 

 unmodifiedly polar, 3^et the latter easily could have become warmed 

 and salted, and thus disguised, through admixture with offshore 

 Atlantic water, and this is probably what happened. Another note- 

 worthy feature is the sudden transition which occurred 65 miles sea- 

 ward of the slope, where saline water above 35''/oo and warmer than 

 10° abutted water fresher than 33%o and colder than 3°, a range 

 of 2°/oo in salinity and 7° in temperature. This is graphically 

 illustrated on profile No. 1, in the compactness and verticality of the 

 isohalines and isotherms between stations 259 and 251. - 



88124—24 8 (109) 



