Wind and Weather 



133 



the land. This accounts for the fact that most of the great deserts 

 of the world, such as the Desert of Gobi in Asia and the Desert 

 of Sahara in Africa, lie in these calm areas. 



The Trade Winds. From the high pressure areas of the 

 horse latitudes some of the descending air flows toward the 

 equator and some toward the poles areas of low pressure. 

 From the northern tropical belt of calms air flows in a south- 

 westerly direction toward the heat equator. From the southern 



Horse Latitude 

 Calms 



Equatorial 

 Calms 



Horse Latitud 

 Calms 



Prevailing 

 Westerly Winds 



North East 

 Trade Winds 



South East 

 Trade Winds 



Prevailing 

 Westerly Winds 



THE WINDS OF THE WORLD 



Which arrows on the globe indicate the trade winds? The prevailing westerlies? 



Trace, on the lines outside of the hemisphere, the course of the anti-trade winds, 



the trade winds, the polar drift, and the westerlies. 



tropical belt air flows in a northwesterly direction toward the 

 heat equator. In each case the air currents are turned from the 

 north and south line toward the west by the rotation of the earth. 

 These two wind currents are called the trade winds because 

 vessels engaged in trade formerly depended on them for motive 

 power. The northern trade winds brought Columbus to America 

 and terrified his sailors because they could not understand how 

 they could ever return against them. 



