NO. 4 TEMPERATURE NARIATIONS IN THE NORTH ATLANTIC I23 



year, February, we have designated those winds as positive for 

 which the isobars at Stad were directed more towards the land than 

 normal and negative, those in which the direction was more sea- 

 wards. For the warm part of the year, August, the winds, that is, 

 the isobars, were on the contrary designated negative when they 

 came from the sea and positive when they were more southerly than 

 the mean direction. 



By multiplying the sine of the so obtained negative or positive 

 angle between the isobar directions of the single years and the mean 

 isobar direction by the value found for the air pressure gradient, 

 we obtained values given in table i6D and in the curve B of plate 

 47, figure 2, February. 



The curve W for the surface temperatures at Ona Lighthouse in 

 February shows a great similarity to the curve B of the air pres- 

 sure gradients for Stad in February, which is the full-drawn curve. 

 Still better agreement is shown with the mean for January and 

 February, w^iich is the heavy dotted curve computed according to 



the expression (see pi. 47, figure 2. February). 



The curve for the surface temperature of Ona Lighthouse for 

 August, which is the full-drawn line of plate 48, figure 2, July- 

 August W, shows also a surprising similarity with the curve of the 

 air pressure gradients for August, which is the full-drawn curve B, 

 and yet better with the curve for the mean of the months July and 

 August, which is the heavy dotted curve B. 



The following results which we had expected are confirmed. The 

 temperature of the coast water at Ona varies with the variations of 

 the air pressure gradients, that is to say, the winds, but oppositely 

 in August and February. 



We will now investigate the relation between the air pressure dis- 

 tribution and the surface temperature on the Norwegian south 

 coast at Torungen Lighthouse, where the conditions are entirely 

 different from those at Ona Lighthouse. Here the whole sea far 

 from the land is covered to a great extent with coast water, which 

 is transported along the coast by the Baltic current, which at almost 

 all times carries its well-mixed water along by this locality south- 

 westwards. We therefore cannot expect that the local winds would 

 have the same kind of an influence on the surface layers as at Ona 

 Lighthouse, depending on whether they are sea winds or land winds. 

 We should rather expect that the weather conditions would govern 

 the warming or cooling of the coast water or surface water of this 



