MOVEMENTS OF THE ATMOSPHERE 



45 



sea-breeze at Coney Island, New York, was found to be 150 meters 

 in August, witb a distinct seaward motion of the air at 200 meters. 

 At Toulon, in the middle of October, 1893, it was found to be 400 

 meters, with a distinct off-shore current at 600 meters. On the 

 coast of California its height is about 2,500 meters. 



Land-Brcczcs. These are generally much weaker than sea- 

 breezes. They result from the more rapid cooling of the land at 

 night, involving a decrease in the pressure of the higher air and an 

 inflow of warm air from the sea. This lowers the surface pressure 

 over the sea and increases that over the land, with the result that a 

 surface current flows seaward from the land. As the land winds 

 increase in length they will fall under the deflective action of the 



Fig. 9. The isobars of India for Jan- Fig. 10. Wind directions in India in 

 uary. (After Bartholomew; winter. (After Koppen ; from 



from SaHsbury.) Salisbury.) 



earth's rotation, and the breeze on the east coast will become a 

 northwest wind on the northern and a southwest wind on the south- 

 ern coast, while the land-breezes on the west coast will become 

 southeast and northeast winds, respectively. The large lakes in like 

 manner influence the formation of land- and lake-breezes, though 

 not to the extent that oceans do. 



Monsoons. These are the seasonal winds, brought about by the 

 heating of the land during the summer and the cooling during the 

 winter. These winds may be regarded as sea- and land-breezes act- 

 ing continuously for nearly half a year each, and hence attaining 

 great velocity. In the mi (Idle and higher latitudes of the northern 

 hemisphere these seasonal winds may even entirely overcome the 

 prevailing or planetary circulation, at least so far as the lower 

 atmosphere is concerned, and may fin-ther exert a powerful influ- 

 ence on ocean currents. 



