These latter will often lead the uninitiated into making serious 

 errors from estimating distances. The most serious restrictions 

 to visibility occur with blowing snow or when air from the lead- 

 ing edge of a low pressure system has sufficient trajectory over 

 the ice packs to permit condensation of water vapor and the con- 

 tinuous formation of heavy fog. (See table IV,) 



CLOUDINESS 



Cloud cover is high throughout the area, amounting to 60 to 90 

 percent and increasing somewhat from December through March. 

 Cloudiness increases and ceilings lower as one proceeds north- 

 ward from the ice pack and approaches the antarctic front. At 

 Little America, Cape Dennison, the Shackleton Ice Shelf, and on 

 the Gauss, cloud covers are predominantly 60 to 70 percent, with 

 only about 40 to 60 percent low cloud cover being experienced at 

 Little America. Over the adjacent sea areas north of the Ant- 

 arctic Circle, on the other hand, cloud covers are usually 80 to 90 

 percent, with about the same percentages of low broken or overcast 

 being observed. Although no data is available relative to cloud 

 conditions inland, it is expected that generally clear skies will 

 prevail. The predominant cloud types are stratus and strato- 

 cumulus, which appear in over 50 percent of total observations 

 taken at Little America, and more frequently over the adjacent 

 water areas. Alto stratus and alto cumulus are also frequently 

 observed. (See table V.) 



TEMPERATURE 



There is little to be added to what has previously been said 

 concerning the temperature in the Antarctic. It is perhaps worth 

 noting that there appears to be no month in which the mean air 

 temperature reaches a temperature in excess of 32° F, It is real- 

 ized that the open lake region discovered by a recent expedition 

 tends to contradict the latter statement, but it is believed that this 

 feature is normally perhaps caused by hot water springs. It is 

 considered that the center cf Antarctica has the coldest winters 

 of the whole world, but there are no existing records to prove or 

 disprove this theory. However, the winters of the Ross Sea re- 

 gion and the ocean coasts are not as cold as those of Siberia. 

 (See table VI and VII.) 



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