Long-term trends and changes in the hydrography of the Faroe-Shetland Channel region 497 



Three months later, in November 1950, only the intermediate Arctic water-mass and 

 no surface Arctic water, was found on the northern section, and even this was in 

 process of cleavage in mid-section by Norwegian Sea water as illustrated in Fig. 10. 



The intermediate Arctic water-mass was entirely absent from the toe of the Channel 

 by May 1951, and almost totally excluded by Norwegian Sea water from the depths of 

 the northern section in June. There was no evidence whatever of its presence on the 

 same section by the month of October, and only an isolated trace appeared two months 

 after. 



500 



TEMPERATURE AND SALINITY 



HORIZONTAL SCALE = 11,000,000 

 VERTICAL SCALE =1 i.OOO 



NOLSiZl, FAROE - FLUCGA, SHETLAND 



(INCOMPLETE) 



F.R.S. "SCOTIA" 



6-7 NOVEMBER, 1950 



Fig. 10 



A return of both Arctic water types was recorded along the entire length of the 

 Faroe-Shetland Channel in May and June 1952, but both were obviously receding 

 from the region one month later, and towards the end of the year had left only 

 isolated " nuclear " traces within the Norwegian Sea water-mass. 



Once again, then, a phenomenon has been witnessed over a group of years which 

 seems not to have been in evidence for at least a number of years previously: and at 

 all events in respect of the Faroe-Shetland Channel region, the conception of long- 

 term trends and changes in hydrographic, including dynamic, conditions seems 

 amply to be in accordance with observational facts. Only systematic and sufficiently 

 intensive and continuous observations on similar lines to those practised in the past 

 few years particularly can serve further to elucidate these interesting and doubtless, 

 in several respects, more or less highly important geophysical phenomena. 



