AEROGRAPHER'S MATE 3 & 2 



same number of rays has to cover a larger 

 area, they cannot produce as much heat when 

 they are dispersed, and the temperature in the 

 area where the sun's rays are dispersed must 

 be lower. Dispersion of insolation in the atmos- 

 phere takes place daily all over the earth due 

 to its rotation. 



Dispersion of insolation also takes place 

 with the seasons in all latitudes of the earth, 

 but especially in the latitudes in the polar 

 areas. 



Scattering 



Insolation is also scattered before it reaches 

 the earth's surface. When insolation is scattered 

 in the sky, it causes us to see a blue sky. 



RADIATION BALANCE 

 IN THE ATMOSPHERE 



The sun radiates insolation to the earth, 

 the earth radiates energy back to space, and 

 the atmosphere radiates energy also. As is 

 shown in figure 12-5, a balance is maintained 

 between incoming and outgoing radiation. This 

 section of the chapter explains the various 

 radiation processes in maintaining this balance. 



Terrestrial (Earth) Radiation 



Radiation emitted by the earth is almost 

 entirely long-wave radiation. Most of the 

 terrestrial radiation is absorbed by the water 

 vapor in the atmosphere with a small amount 



Short *p 



REFLECTED BY 

 EARTH, CLOUDS 

 AND ATMOSPHERE 

 TO OUTER SPACE 



36% 



t 



OUTER SPACE 



I 



NOTE< 





36% OF INCOMING INSOLATION 



INITIALLY REFLECTED 





8% 



Radiated 



<> 



A 



UPPER ATMOSPHERE 



13% 



ABSORBED BY 

 ATMOSPHERE 



o 



<^ 



^ 



<a 







Figure 12-5. — Radiation balance in the atmosphere. 



256 



209.5 



