MOVEMENTS OF ATMOSPHERE GULDBERG AND MOHN 205 



From §12 we have 



P tt k 



H cos a 



and 



a' = P U* r > — 

 a 10 8 



In the interior portion the depression is equal to 



I 



r r G ro 



dp = I — rdr = \G 9 r 



r = '- r = 



and in the exterior portion, the depression is equal to 



\ dp= [l- dr + T* dr ) = 



*J r = r *-S r = r (1 



• - ta «--(i) + »-SM7 



Neglecting the term I ° J and noticing that 



C-- + -, 



we get the total depression between the center and the point whose 

 radius is r, 



Do = a( i + log • nat • ( - ) ) + — 2 



If the radius r denotes the radius of action of the system, we can 

 determine it by giving to U in the equation 



r U 



a conventionally slight value. In violent cyclones we assume U =5 

 meters per second. It seems that the ratio r/r falls between 2 and 

 10. 



The time that a particle of air requires to pass through the exterior 



