160 R. Mountford Deeley — Cyclones and Climate. 



Anticyclonic areas are now regarded as being the normal con- 

 ditions of the atmosphere in which cyclones move, rather than as 

 special features of the atmospheric distribution of temperature and 

 pressure. 



Fig. 1 is a diagrammatic section of the atmosphere from the 

 equator to the pole. The isothermal lines drawn in full are in 

 accordance with the teachings of registering balloon soundings, but 

 the dotted lines are purely theoretical. The great rise of the 

 isothermals over latitude 30° is probably more pronounced in the 

 diagram than it should be. B B is the line of separation between 

 the stratosphere and the troposphere. Discussion now centres itself 

 mainly on what takes place where these two portions of the 

 atmosphere meet. 



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As a result of the consideration of a large number of atmospheric 

 soundings Dines has drawn a diagram showing the temperature 

 conditions obtaining in the average cyclone. It is shown in Fig. 2. 

 Here the arrows indicating the probable nature of the very slow 

 general circulation of the air, to and from the centre of the cyclone, 

 have been added by the writer. The similarity of the temperature 

 distribution shown by these two diagrams is very striking. The 

 line of junction B B separating the stratosphere from the troposphere 

 dips down in the travelling cyclone just as it does in the polar 

 cvclone. 



