NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 



69 



Our curves then show not merely the variations during the two 

 months of our period of investigation from the beginning of Febru- 

 ary to the middle of April, but also certain great features which 

 remained for a long period unchanged. 



It is therefore not improbable that at least the principal features 

 of these variations occur in the average yearly temperatures for 

 the surface in our fields, although of course in the yearly curves 

 the variations would be smaller and more smoothed out. 



We have had no opportunity to collect the observational material 

 required to investigate this matter. The above mentioned Danish 

 observations north of 50° north latitude and those of Petersen and 



1898 )900 



991' 



Figure t^t^. Curves for the yearly means of temperature anomalies in the 

 four 10° longitude fields of the Danish observations (see figs. 31 and 32). Full- 

 drawn curves indicate the mean of the years running from September to 

 August, the dotted curves the mean of the calendar years. 



Liepe furnish, however, a means of studying the question some- 

 what more closely. 



In figure 33, curves I to IV give a representation of the yearly 

 mean for the four above-mentioned Danish fields. The full drawn 

 line shows the mean for the twelve months from the ist of Septem- 

 ber of the previous year to the end of August of the given year, 

 while the dotted curves show the mean values for each calendar 

 year. If one compares these curves with the curves for February 

 and March- April (see figs. 31 and 32) an unmistakable similarity 

 between the characters of the single curves is seen. The similarity 

 is even better than the incompleteness of the material would lead 

 one to expect. It is also clear that a thorough and analogous dis- 

 similarity exists between the types of curves for the eastward and 

 the two western fields. 



