METEOROLOGY OF AMERICAN ANTARCTIC 31I 



Over Bellingshausen Sea the direction of the winds from the west 

 in winter on board the Belgica seems also to indicate higher pressure 

 .to the north of the 70th parallel than to the south. 



WIND VELOCITY 



In the vicinity of Tierra del Fuego the velocity of the wind is 

 greater in summer than in winter. At Orange Bay, near Cape Horn, 

 the mean annual velocity is 6.6 meters per second, 7.8 meters in 

 summer, 6.0 meters in winter. 



In summer on the average the wind attains a velocity of 15 meters 

 per second every day. Every month of summer has a mean of 50 

 hours of strong gales (velocity greater than 18 meters per second), 

 whereas there are 23 hours of such winds every month in the winter. 

 Of each 100 strong gales 47 blow from the west and 44 from the south- 

 west. These strong gales occur during a rise in the barometer. During 

 the fall preceding the rise there are only changeable winds of varying 

 strength, accompanied by rain ; a west and southwest gale sets in as soon 

 as the barometer has begun to climb again. This special circumstance 

 is certainly due to topographic conditions, Orange Bay being situated 

 east of Tierra del Fuego and protected from the north and northwest 

 winds which should occur on the arrival of a low-pressure area. 



The lows almost always pass by to the south of Cape Horn. They 

 succeed each other without interruption, and the barometric curve 

 is nothing but a series of more or less long and more or less deep 

 fluctuations. The annual variation of gale frequency shows that the 

 depressions pass near Cape Horn more frequently in summer than 

 in winter. 



At the Falkland Islands and South Georgia southwest and west 

 gales also predominate but not as exclusively as at Orange Bay. Gales 

 from the north and northwest are rather frequent. 



At the South Orkneys the mean velocity of the wind is considerably 

 less in summer than during other seasons, but the greatest mean 

 velocity is observed in spring and autumn. Gales are a little less 

 frequent than at Cape Horn. In April and September 50 hours of 

 winds whose velocities are greater than 18 meters per second were 

 observed, whereas during each month of summer only 12 hours of 

 such winds were observed. Northwest and southeast winds between 

 them include practically all of these strong gales. Generally the 

 barometer falls with winds from the northwest and rises with winds 

 from the southeast. 



At Snow Hill, on the east coast of Graham Land, summer is also the 

 season when the velocity of the wind is least. The gales blow almost 

 exclusively from the southwest with a rising barometer. During the 

 fall of the barometer the winds are relatively weak and from the 



