206 HOBBS— ROLE OF GLACIAL ANTICYCLONE [April 24, 



referred to the plateau surface, the pecuhar shifting clouds so often 

 observed by Scott and Amundsen are at a low level. The diurnal 

 temperature chart published by de Ouervain for his transection of 

 Greenland, shows that radiation from the surface is apparently but 

 little interfered with by clouds after the central plain has been 

 reached. The abrupt change from this condition to one of small 

 daily range of temperature, is found on both margins of the summit 

 plain. 



The Cirri Above and About the Existing Continental 



Glaciers. 



The Earlier Data. — The relative abundance of cirrus and cirro- 

 stratus clouds, not only above but about the margins of the con- 

 tinental glaciers, will be patent to any one who will read the lists 

 of cloud observations which are published in the reports of the ex- 

 ploring expeditions."'' In 191 1 it was possible to cite the observa- 

 tion of Nansen, that during his crossing of the inland-ice though 

 the sky was in the main clear, those clouds which were present 

 were generally the cirri or some combination of these with cumuli 

 or strati. From the Shackleton expedition in the Antarctic it was 

 learned that the upper air currents near the winter station generally 

 appeared to move in from the northwest quadrant and veer south- 

 erly as they advanced toward the pole. The " polar bands" or 

 "Noah's Arc" clouds (cirro-strati) in general moved southerly, 

 but to the west of the Ross Sea, the " polar bands " moved in from 

 the north northeast or northeast veering round from the north. 

 Thus, as a general rule, it would appear that in this region the 

 upper currents carrying the cirri move roughly parallel to but in 

 opposite direction from the stronger surface currents. In the same 

 region additional evidence was derived from the behavior of the 



"^ See, for example: "Wilkes Exploring Expedition (when off the Ant- 

 arctic Continent)," Vol. XL, Meteorology, pp. 276-291; Mohn und Nansen, 

 " Durchquerung von Gronland," Pet. Mit., Erganzungsh. 105, pp. 22-29; Due 

 d'Orleans, " Croisieres oceanographiques dans la mer du Gronland en 1905, 

 Resultats Scientifiques," Bruxelles, 1907, pp. 52-67 ; Stade, " Gronland Expe- 

 dition der Gesellschaft fiir Erdkunde," Vol. 2, pp. 417-441 ; Wegener, " Me- 

 teorologische Terminbeobachtungen," etc., Med. am Gronland, Vol. 42, 191 1, 

 pp. 202-311. 



