Chapter 12— THE GOVERNING FUNDAMENTALS OF METEOROLOGY 



Exosphere. — The very outer limit of the 

 earth's atmosphere is regarded as the exo- 

 sphere. It is the zone in which gas atoms 

 are so widely spaced that they rarely collide 

 with one another and have individual orbits 

 around the earth. It is believed not to be of 

 meteorological significance. 



ELECTRICAL CLASSIFICATION. — The pri- 

 mary concern with the electrical classification 

 is the effect on communications and radar. 

 The electrical classification outlines three 

 zones— the troposphere, the ozonosphere, and 

 the ionosphere. 



Troposphere. — In the troposphere, the pri- 

 mary emphasis is on the formation of inversions 

 of temperature; that is, the increase of tem- 

 perature with gain in altitude and on variation 

 in moisture with altitude. Certain conditions 

 cause significant bending or refraction of radio 

 and radar waves. Under certain circumstances 

 the range of communication and radar is thereby 

 increased, and under other circumstances the 

 range is shortened. 



Ozonosphere. — This layer is nearly coin- 

 cident with the stratosphere. As was discussed 

 earlier in this section, the ozone found in this 

 zone is responsible for the increase in tem- 

 perature with height in the stratosphere. 



Ionosphere. — The ionosphere extends from 

 about 40 miles (200,000 ft) to an indefinite 

 height. Ionization of air molecules through this 

 zone provides conditions that are favorable for 

 radio propagation. This zone is subdivided into 

 the D, E, and F regions. The F regions are 

 considered the most important for increasing 

 communication capabilities. 



HEAT TRANSFER 



The atmosphere is constantly gaining and 

 losing heat, and heat is being transported from 

 one part of the world to the other by wind 

 movements. It is due to the inequalities in gain 

 and loss of heat that the air is almost constantly 

 in motion. The motions and heat transformations 

 are directly expressed by wind and weather. 



Methods 



In meteorology, one is concerned with four 

 methods of heat transfer. They are conduction, 

 convection, advection, and radiation. Heat is 



transferred from the earth directly to the 

 atmosphere by radiation, conduction, and 

 advection, and within the atmosphere by radia- 

 tion, conduction, and convection. Advection, a 

 form of convection, is used in a special manner 

 in meteorology; it is discussed as a separate 

 method of heat transfer. As radiation was 

 discussed earlier in the chapter, this section 

 will concern only conduction, convection, and 

 advection. 



CONDUCTION. — Conduction is the transfer 

 of heat from warmer to colder matter by 

 contact. Although of secondary importance in 

 the heating of the atmosphere, it is a means 

 by which air close to the surface of the earth 

 heats during the day and cools during the night. 

 Even if air is a poor conductor (as shown 

 by the use of dead airspace in Thermopane 

 glass and the airspaces used as insulation in 

 buildings), the heating and cooling of air at 

 the immediate surface of the earth are 

 accomplished by conduction. 



CONVECTION. — Convection is the method 

 of heat transfer in a fluid resulting in transport 

 and mixing of the properties of that fluid. 

 Visualize a pot of boiling water. The water at 

 the bottom of the pot is heated by conduction. 

 It becomes less dense and rises. Cooler and 

 denser water from the sides and the top of 

 the pot rushes in and replaces the rising water. 

 In time, the water is thoroughly mixed. As 

 long as heat is applied to the pot, the water 

 continues to transfer heat by convection. The 

 transfer of heat by convection in this case 

 applies only to what is happening to the water 

 in the pot. In meteorology, the term "con- 

 vection" is normally applied to vertical trans- 

 port. 



Vertical transfer of heat in the atmosphere 

 works in a similar manner; warmer, less dense 

 air rises and is replaced by descending 

 cooler, denser air, which in turn, acquires 

 heat. 



Convection occurs regularly in the atmos- 

 phere, resulting in turbulent air and large 

 cumulus-type clouds when sufficient moisture 

 is present. The specifics of convection were 

 discussed in greater detail as it pertained to 

 the SKEW-T Log "P" Diagram in chapter 10 

 of this manual. 



ADVECTION.— Advection is really a form 

 of convection, but in meteorology it means the 



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