NO. 4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 4I 



mann inclines " toward the view that besides the reactions of air 

 pressure distribution and ocean temperature described by Meinardus, 

 there is in operation a more powerful higher cause which we do 

 not yet understand. It is this which calls forth both the continuity 

 and the periodic discontinuity, or as we might better say, the change- 

 ability of the air pressure distribution, and thereby induces the 

 parallelism of the ocean and air temperatures as a consequence 

 of it." 



The variations in the temperature of the ocean and their connec- 

 tion with the variations in the air pressure distribution over the 

 northern regions and in the air temperature in Europe are investi- 

 gated in the above mentioned treatises only wdth the help of the 

 yearly observations of the surface temperature of the water along 

 the Norwegian coast and the coast of Jutland. Only in later 

 years have the variations of the surface temperature in the Atlan- 

 tic Ocean itself been methodically investigated. 



Here we must give first place to Dr. Johannes Petersen's treatise 

 entitled " Non-periodic temperature variations in the Gulf Stream 

 and their relation to the air pressure distribution" (1910). This 

 is based on the observational material of the Deutschen Seewarte 

 for the same region along the course Channel to New York, which 

 we have investigated. Petersen has twelve stations along this route, 

 with an interval of about 5° of longitude between these stations/ 



Each station consists of a 1° field (covering 1° in longitude and 1° 

 in latitude) within which all the observations for each month of the 

 year were assembled (without regard to the decades) and for the 

 twenty years from 1883 to 1902. This arrangement has the weak- 

 ness that with such small fields the number of observations even for 

 a whole month together is too small in order to give trustworthy 

 values, particularly in regions where the variations are very great. 

 The number of observations for each station per month, says Peter- 

 sen, varied between five and twenty, but nevertheless there were many 

 gaps. His observational material for the time February to April 

 was considerably less than that which we have employed, on which 

 account the temperature curves for his individual stations show on 

 the whole a less good agreement than the curves for our individual 



' The situations of the observation stations are as follows : 



Station I 2 3 4 5 6 7 8 9 10 li 12 



Longitude W 12" 17° 22° 27° 31° 36° 41^ 46° 51° 56° 61° 66" 



Latitude Jan.-July 49° 49° 48° 47° 46° 45° 43° 4i° 41° 40° 40° 40° 



Latitude Aug.-Dec 50° 50° 50° 49° 49° 48° 47° 46° 45° 44° 42° 41° 



4 



