ANTARCTIC ADVENTURE AND RESEARCH 



streams out on the surface, removes moisture from the 

 central region. 



W. H. Hobbs lays great stress on the domelike shape 

 of the ice cap (see Figure 29), which is some ten 

 thousand feet near the Pole, and thence descends fairly 

 slowly and then more steeply to sea level in Mawson's 

 region (66° S.). The plateau is about eight thousand 



Cei I ing 



Fig. 29. — The glacial anticyclone (in section) 



(After W. H. Hobbs.) 



feet at latitude yj^ and seven thousand feet at lati- 

 tude 73°. He states his case somewhat as follows : 



If there were no extensive high and snow-covered areas 

 in the Antarctic it is clear that the circulation would be less 

 vigorous. When the slope is very gentle air drainage is 

 necessarily sluggish, and such regions (when there are no 

 higher surrounding mountains) can and do establish (i) a 

 circulation of the upper air from the ocean to the higher 

 portions of the plateau; (2) a well defined increase of 

 temperature for the first few hundred meters of elevation ; 



(3) a slow settling of the air onto the cold surface below; 



(4) the precipitation, without cloud, of fine snow crystals 



194 



