PRECIPITATION 31 



complex question which can only be dealt with satisfactorily by able meteorologists.* 

 Our impression at present Is : 



(1) That if a great permanent high-level cyclone exists it does not carry any very 

 appreciable quantity of snow far inland, for if it did there would be far more 

 fresh-falling snow than has actually been observed towards the middle and end 

 of blizzards. 



(2) That the so-called permanent anticyclone of Antarctica is represented by 

 a thin mass of cold stagnant air more or less concentric to the main Temperature 

 Pole, in winter resting partly on the second Cold-Pole, discovered by Amundsen 

 to the S. of " Franiheim." That this cold air mass does not radiate outwards 

 continuall}' and systematically, but is spasmodic and local in its outrushes, breaking 

 away often a bit at a time, each unit rolling down separately to sea level as an 

 independent air avalanche. 



(3) That such outrushes of cold air are partly replaced by a surface inflow, partly 

 by an inflow at a high level, constituting for the time being a high-level polar 

 cyclone. Probably, like the Polar cyclone, the high-level Polar cyclone is compound 

 rather than simple. 



(4) That it is these surface currents moving Pole-wards that are responsible for 

 the heaviest snowfall, at all events in summer. In winter when atmospheric 

 circulation in general is accelerated in Antarctica the high-level air current, like that 

 which passes over the Magnetic Pole Plateau, may contribute to the snowfall to a 

 greater extent than it does in the summer. 



(5) Sea breezes in the Ross Sea, set up largely by the differential heating of the 

 exposed rock masses of the Antarctic Horst as compared with the water surface of 

 the Ross Sea, ai-e responsible for a good deal of snowfall along the Western 

 Mountains. 



(6) The surface relief of the land and the distribution of land and tvater have in 

 many cases a 'paramount influence on the direction of the preixilent tvinds and 

 consequently on the snowfall of Antarctica. This is a fact which seems to stand out 

 more clearly than any other in the meteorology of this region. 



Amount of Snowfall. Observations at Cape Royds showed that the snowfall of 

 the year 1908 was approximately equal to about 9 inches (230 mm.) of rain. This 

 estimate is approximately correct, but allowance must be made for the fact that 

 it was extremely difficult to distinguish between old drift snow which found its way 

 into the rain-gauge and new-falling snow. The result is intended to be an 

 approximation of the amount of actual snowfall during the year. 



On the Great Ice Barrier in the latitude of Minna Bluff", 78° 45' S., the amount 

 of snowfall is not known, but it was found that over 8 feet (2 '4 m.) of snow had 



* Much fresh light will be thrown upon this problem when Dr. G. C. Simpson, the meteorologist to 

 Captain Scott's expedition of 1910-13, collates and publishes his unique records obtained in the Ross 

 Sea region. 



