NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 121 



VIII. THE SURFACE TEMPERATURE OF THE OCEAN ON THE 

 NORWEGIAN COAST IS DEPENDENT ON THE WINDS 



We shall now investigate what influence the winds produce on 

 the surface temperature of the ocean along the coast of the conti- 

 nents, and for this purpose shall employ the series of observations 

 which have been made for a long term of years on the coast of 

 Norway. 



Prof. Otto Pettersson and later also Meinardus have assumed that 

 the surface temperature on the Norwegian west coast, at the light- 

 houses Utsire, Helliso, and Ona, changes with the temperature of 

 the water which is brought by the warm Atlantic current, the Gulf 

 Stream, through the ocean to the Norwegian coast. This appears 

 surprising, for it is well known that the surface water along the 

 Norwegian coast where the observations referred to were made 

 is notably coast water as indicated both by its salt contents and 

 its temperature, and has very little similarity to the water which 

 is carried by the Atlantic Ocean currents on the surface far out 

 in the open ocean. 



The coast water is well stratified and the surface is very light on 

 account of its high percentage of fresh water, hence the vertical 

 circulation is greatly hindered, and on this account the yearly tem- 

 perature amplitude of the thin surface layer is relatively very great, 

 with very few low temperatures in winter and high in summer. It 

 is therefore easy to see that here the winds may produce great tem- 

 perature variations. 



PROBABLE ACTION OF THE WINDS ON THE COAST WATER 

 TEMPERATURE IN WINTER AND SUMMER 



During the coldest part of the winter different conditions of the 

 atmosphere would produce the following principal effects on the 

 surface temperature on the Norwegian west coast. 



In calm weather, the clouds are generally few and the outgoing 

 radiation consequently is strong with a considerable cooling of the 

 surface particularly in the inner parts of the fjords. On the open 

 ocean, this action is less notable on account of the vertical circula- 

 tion and because the outgoing radiation is hindered by the foggy 

 air, hence the surface temperature of the ocean increases consider- 

 ably from the inner parts of the fjords toward the open sea. 



When the winds blozv from the land, there is cold clear weather, 

 strong outgoing radiation and consequently strong tendency to cool 

 the surface. The cold surface water is driven out of the fjords, sea- 



9 



