98 



WIND. 



Taking the annual variation to consist of — 



(a) a .siraj)le period with a miiiimiun in the summer and a maxinmm in the wintei', 



(6) a pronounced secondaiy maximum in Febmaiy and March, 

 it will be found tliat the former of these is present at all stations near the Antarctic Con- 

 tinent for which we have da,ta except Framlieim and Cape Adare, while the latter is present 

 at all except the Belgica station. 



Table 56. 



Annual Variation of Wind at Antarctic Stations {miles per hour). 



Station. 



Framheim 



Hut Point 



Gajje Evans . 

 Cape Adare . 

 Belgica * 

 Snow Hill * . 

 Gauss Station * 

 Petermann Island . 



110 



210 



98 



10-8 



132 



6.1 



65 8-9 10-5 9-2 



9-8 



10-5 



18-; 



101 



18-3 



110 



1.5-0 



12-9 



14-5 



11-0 



17-6 



6-6 



9-2 



17-7 



9-2 



13-7 



11-4 



9-5 



17-5 



6-4 



7-4 



19-0 



10-5 



10-7 



The cause of the greater wind in the winter than in the summer is without doubt tlie 

 annual variation of the difference in temperatiu-e between the continent and the ocean. We 

 have no actual temperature observations from the interior of the continent during the winter 

 but there can be no question that the temperature difierence between the continent and the 

 surrounding ocean is greater in the winter than in the summer. This causes an intensification 

 of the Antarctic anticyclone and in consequence increased wind velocity along the coast. 



The explanation of the secondary maximum of wind velocity in February or March is 

 not obvious. It may be connected mth the rapid fall of temperature over the continent 

 during these two months while open water extends almost up to the margin of the permanent 

 ice. This would cause a temporary closing up of tlie isothernLS near the edge of the conti- 

 nent and therefore an increased pressure gradient. Further observations are necessary before 

 this point can be settled. 



* From table 62 of Bodtnan's discussion of the Snow Hill results. 



