Sea, prevail from the south with a secondary maximum from the 

 northeast. This would seem to indicate a conflict between the out- 

 flow from the continental anticyclone and the Polar Anticyclone. 

 At no great distance above the surface the air flow is largely from 

 the northeast and remains in that quadrant up to at least 13,000 

 feet. During the spring months the prevailing winds aloft are 

 easterly. In the summer surface winds are northerly and flow 

 into the heat low of the continent, but above 1,600 feet and continu- 

 ing up to 13,000 feet the prevailing winds are southerly. During 

 autumn there is a return of easterly winds aloft. The average 

 wind velocities aloft are greatest in summer, blowing from 16 to 

 22 m. p. h., while velocities in winter range from 14 to 18 m. p. h. 

 Surface wind velocities are greatest in winter, and the occurrence 

 of gales is likewise highest then, averaging nine per month, against 

 an average of three per month during the summer, for a yearly 

 total of 80. 



A summary of the winds-aloft data gathered on the Norwegian 

 north polar expedition in the Maud follows. The data were gath- 

 ered in the years 1918-1925, between latitudes 77°33' N. and 70° 

 43' N., and between longitudes 105°40' E. and 175° 15' W. 



For all seasons, combined surface winds showed the greatest 

 frequency from northeast to southeast with 51 percent of all ob- 

 served winds from that quadrant. The average velocity of these 

 prevalent winds was 9 m. p. h. At 3,000 feet all wind directions 

 are about equally represented, except for north and northwest 

 which have about half the percentage of other directions. The 

 velocity, as well as the prevalence, is least for these north and 

 northwest winds, being 16 m. p. h. with southeast winds having 

 the greatest velocity, 19 m. p. h. At 6,000 feet the situation is 

 similar to that at 3,000 feet, except that westerly winds have a 

 slight edge in percentage. At 13,000 feet ths weight of prevalence 

 of west and southwest wind increases but all other directions are 

 still well represented. Velocities at this level are least for south- 

 east winds at 17 m. p. h., and greatest for west winds at 22 m. p. h. 

 At 20,000 feet the weight of prevalence of west and southwest 

 winds increases to a combined total of 33 percent, southeast being 

 the least with 5 percent, and all other directions averaging 11 per- 

 cent each. Velocities at 20,000 feet are greatest for west and 

 northwest at 25 m. p. h. and least for southeast at 19 m. p. h. 



From an average surface velocity of 7.8 m. p. h. there is a sharp 

 increase to 17.4 m. p. h. at 3,000 feet above sea level. From 3,000 



109 



