common to all stations in the inner polar areas. The temperatures 

 in the pack ice never deviate far from the freezing point. The di- 

 urnal ranges are smaller and the interdiurnal changes are less 

 in summer than in any other season. Warm air from inland is 

 often transported a considerable distance from the coast, but in 

 passing over the icy waters it is cooled so effectively by contact 

 with the ice that a sharp inversion is formed. Thus, the warm 

 air current flows at some distance from the ground and has prac- 

 tically no influence on the surface temperature. Considerably 

 higher temperatures are found on the coast and the transition 

 from coastal to maritime conditions takes place within a very short 

 distance. However, this characteristic holds for the surface 

 layers only and is not found at higher levels. The discontinuity, 

 therefore, represents only a quasifront and is of no consequence 

 to the circulation of the atmosphere. 



The warmest month in the Arctic over both land and sea areas 

 is, with but few exceptions, July. However, the August tem- 

 perature chart is representative of summer conditions. It is 

 highly probable that everywhere in the Arctic Ocean the average 

 temperature for July is within a few tenths of a degree of the 

 freezing point, whereas in June and August the average is slightly 

 below 30° F. 



The highest temperature observed on the Fram expedition was 

 39.2° F. in June, 1896, and observers on the Maud found an ab- 

 solute maximum of 38.3° F. in June, 1923. That both values 

 occurred in June is probably explained by the iact that maximum 

 cloudiness in this area occurs in July and August. At coastal sta- 



Figure 3-1 4. — Warmest month in the Arctic. 



127 



