1915- ^*^- -• 



SPITSBERGEN WATERS. 



Bank-Water. 



During our northward course we took several vertical series of obser- 

 vations (Stations i — 4» on the Bear Island Bank. They demonstrate the 

 tendency of the bank-water towards vertical uniformity over the shallow 

 parts ot the banks of the Ocean. I have previously [see especiallv 1913, 

 p. 24, ei seq.] pointed out that this must be so, owing to the vertical 

 circulation caused by the cooling of the sea-surtace during winter and 

 spring. In these northern regions it is also of importance for the vertical 

 circulation during the winter that the salinity of the surtace-layer is much 

 increased by the formation of ice during the winter [see 1906, p. 31]. In 

 the course of the winter the shallow banks of the ocean are thus graduallv 

 covered with comparatively cold layers of water, which have nearly uniform 



7y -T 



3 



1: Vi:. 



2 



1 



S3 3»! 5« 



Ï0O - 



200 ~ 



rig. 3. Section across the Bear Island Bank. Jaiy lo — 12, 1912 'see Fi 

 Horizontal Scale i : 2,000.000. Vertical Scale i : 5,000. 



temperature and salinity between the surface and the bottom. These 

 nearly homogeneous masses of water remain as a rule over the banks 

 for a remarkable long time into the summer. The greater and shallower 

 the bank, the longer does this period become, and this fact seems to show 

 that the horizontal circulation of the water over the bank must be unusuall}' 

 slow, so that it takes a long time for the water to be removed and replaced 

 by other water-masses. The slow horizontal circulation of the banks must 

 be due to the uneven bottom, which offers much resistance to the horizontal 

 movement of the water. The tidal currents may nevertheless be very strong 

 over the banks, because the tidal waves are much increased in hight over 

 the shallow sea; but these periodical currents, or orbital movements, do 

 not finalh- transport the water away from the banks. 



Our first two series, at Stations i and 2. were taken at somewhat 

 deeper places than the next series, at Stations 3 and 4, and there was a 



