Long-term trends and changes in the hydrography of the Faroe-Shetland Channel region 495 



not in fact at all times bypass tiie Channel in its eastward trend across the southern 

 reaches of the Norwegian Sea. 



Except for a single 34-89" ,^ record in August 1948, this year appears to have been 

 devoid of any Arctic water in the Channel, but in early March 1949 (Fig. 5), deep 

 water conditions there were radically different from those normally anticipated. 

 The expected Norwegian Sea water bottom layer was then entirely displaced below 

 about 350 to 700 metres by the Arctic water-mass, being sandwiched in a narrow 

 undulatory band in cross-section between it and the uppermost oceanic water-mass. 

 Not only so, but apparently still another water-mass of still lower temperature and 

 lower saUnity (34-79 °/o„ to 34-84°/3o) than the above-defined Arctic water-mass seems 

 to have underlain to some extent the latter in the deepest part of the Channel against 



1000 



TEMPERATURE AND SALINITY 



H0BI20NTAL SCAIE = I: 1,000,000 

 VERTICAL SCALE = I' 5,00O 



NOLS0, FAROE -FLUCCA, SHETLAND 



F. U.S. "SCOTIA" 

 22-24 NOVEMBEB, 1949 



Fig. 8 



the bottom of the continental slope. There is sufficient reason to designate this new 

 water-mass surface Arctic water, thus distinguishing it from the intermediate Arctic 

 water-mass immediately above it in the Channel region. At the end of April 1949 the 

 intermediate Arctic water-mass was located at the southern extremity of the Channel, 

 in its toe, so to speak, between the Wyville Thomson Ridge and the Faroe Bank. Five 

 months later, in September 1949 (Fig. 6), not only did surface Arctic water occupy 

 more than half of the deep-water cross-sectional area of the northern part of the 

 Channel, the two Arctic water-masses together there again ' supporting ' only a 

 narrow band of Norwegian Sea water beneath the oceanic mass — except against the 

 continental slope where surface Arctic water appears to have been directly contiguous 



