NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 25I 



If we consider first the last named curves it must be surprising 

 what extraordinary agreement between the different curves here 

 appears, particularly in curve I for the air pressure difference in the 

 North Atlantic and curve II for the air temperature in all of Norway. 

 These two curves agree even to the smallest feature, so that almost 

 every small depression or wave in the curve of air pressure dif- 

 ference a little later occurs in the temperature curve for Norway. 

 In other words this shows that the shorter fluctuations of a few 

 years only in the air temperature in Norway depend principally on 

 the air pressure difference in the North Atlantic, so that the air 

 pressure gradients, that is, increase of atmospheric circulation over 

 the Atlantic Ocean, corresponds to an increase of temperature in 

 Norway and vice versa. For the variations of a longer time interval 

 the matter may run otherwise,. shown in curves I and II. 



If we consider the relation of the surface temperature in the 

 most westerly Danish fields (curves III and IV) and the air pressure 

 difference over the North Atlantic Ocean more closely, we find the 

 opposite case, namely, that an increase of the air pressure difference 

 with an increase of atmospheric circulation over the Atlantic Ocean 

 corresponds to a depression of the surface temperature for these 

 Danish fields and vice versa. The reader should observe that the 

 curves III and IV are inverted. In the most easterly Danish field, 

 between o° and io° west longitude the relation is -partly opposite. 

 There an increase of the atmospheric circulation, in part at least, 

 brings on a fall of temperature just as in Norway, only with less 

 regularity, since the relations in this most easterly Danish field are 

 partly a mixture of the relations which occur in Norway and in the 

 westerly Danish fields. 



We have already remarked the close agreement between the 

 curves for this most easterly Danish field (and in part also for the 

 field further westerly between io° and 20° west longitude) and the 

 curves for the fields further south in the easterly part of the Atlantic 

 Ocean, as, for example, the curves for Petersson's stations I and II 

 and Liepe's most northerly stations I, II, III. We have also spoken 

 of the similarity between the February curve for the most easterly 

 Danish field at 0° to 9° west longitude and the February curves for 

 the most easterly of the regions investigated by us further south in 

 the shipping course, Channel to New York, and also in the region, 

 Portugal to the Azores. From all this we must draw the con- 

 clusion that the temperature rise over north Europe which follows 

 an increased air circulation also holds for the surface temperatures 



