204 DISCOVERY REPORTS 



The whole situation becomes compHcated when this effect of suspended inorganic 

 matter is considered, as one of the most favourable factors for diatom growth is pro- 

 longed sunshine. This, however, leads to high air and surface temperatures and so in- 

 creases the amount of thawing, and incidentally the amount of inorganic mud carried 

 into the bay. 



METEOROLOGICAL FACTORS 

 WIND 



When investigating the movement of shore water at Hope Point, Mr Deacon found 

 that its relation to the wind was similar to that found by Gran and Gaarder (1918) on a 

 much larger scale in the surface layers of Oslo Fjord. With onshore winds surface water 

 was piled up inside and the salinity reduced, while with offshore winds this state of 

 affairs was reversed, the surface water being driven out, while the deeper-lying water 

 of higher salinity was brought to the surface. 



At our station out in the bay this simple relation was not manifest, and in the account 

 which follows it should be borne in mind that the depth out in the bay is great, and the 

 shoaling where it does take place is very abrupt, so that there is nothing corresponding 

 to the shallow ridge across Oslo Fjord at Drobak. 



Owing to the configuration of the surrounding mountains the prevailing winds are 

 usually deflected so that they blow somewhat from the north, and when the north and 

 south components of the wind are plotted against the mean sahnity for the upper 

 20 m. of water (see Fig. 81) it appears that with northerly winds the salinity is raised, 

 while with southerly winds it is lowered. It seems that when northerly winds pile up 

 the surface water inshore, outside surface water of high salinity moves in over the 

 heavier, still more saline water of the lower layers, so that the salinity of the upper layers 

 at the station position 2 miles out is raised. 



With southerly winds, as Deacon found, the surface water of low salinity is driven 

 offshore, and the salinity inshore rises as the deeper layers come to the surface. This 

 apparently leads to the lowering of the salinity of the upper layers out at the station 

 position, where the effect of the shore water drifting out is felt. The two contrasting 

 sets of conditions may be represented diagrammatically as in Fig. 82. 



Fig. 82. Schematic diagram illustrating the apparent effect of wind on the surface layers in 



East Cumberland Bay. 



In practice, of course, conditions are often compHcated by the extreme variability 

 of the wind, and at times by the presence of ice. Moreover, when the northerly 



