Chapter 12— THE GOVERNING FUNDAMENTALS OF METEOROLOGY 



(about 8 percent) being radiated directly to 

 outer space. Some is carried aloft by convection 

 and turbulence, and the condensation-precipi- 

 tation-evaporation cycle (hydrological cycle) 

 carries the remainder into the atmosphere. 



Atmospheric Radiation 



The atmosphere reradiates to outer space 

 most of the terrestrial radiation (about 43 per- 

 cent) and insolation (about 13 percent) that it 

 has absorbed. Some of this radiation is emitted 

 downward and is known as COUNTERRADIA- 

 TION. This radiation is of great importance 

 in the greenhouse effect. 



Diffuse Sky Radiation 



About 25 percent of the incoming solar 

 radiation is scattered by the atmosphere. About 

 two-thirds of this scattered radiation reaches 

 the earth as diffuse sky radiation. Diffuse sky 

 radiation may account for almost 100 percent 

 of the radiation received by polar stations 

 during winter. 



Summary 



This is the account of the TOTAL radiation. 

 Some of the radiation makes several trips, 

 being absorbed, reflected, or reradiated by the 

 earth or the atmosphere. Insolation comes into 

 the atmosphere, and all of it is reradiated. 

 How many trips it makes while in our atmos- 

 phere does not matter. The direct absorption 

 of radiation by the earth and atmosphere and 

 the reradiations into space balance. 



Heat Balance and Transfer 

 in the Atmosphere 



Due to the differential insolation (uneven 

 heating) the Tropical atmosphere is constantly 

 being supplied heat and the temperature of the 

 air is thus higher than in areas poleward. 

 Because of the expansion of warm air, this 

 column of air is much deeper than over the 

 poles. At the poles the earth receives little 

 insolation, and the column of air is much shorter 

 and heavier. This differential in insolation sets 

 up a circulation that transports warm air from 

 the Tropics poleward aloft and cold air from 

 the poles equatorward on the surface (fig. 12-6). 

 Modifications to this general circulation are 

 discussed in detail in chapter 13. 



Although radiation is considered the most 

 important means of heat transfer, it is not 

 the only method. There are others such as 

 conduction, convection, and advection which also 

 play an important part in the meteorological 

 processes. These will be discussed in more 

 detail later in the chapter. 



AREA OF LEAST 

 INSOLATION 



AREA OF 

 GREATEST 

 NSOLATION 



AREA OF LEAST 

 INSOLATION 



209.6 



Figure 12-6. — Beginning of a circulation. 



MATTER 



DEFINITION 



Matter is defined as anything that occupies 

 space and has weight. Matter is around us in 

 some form everywhere in our daily life — the 

 air we breathe, the water we drink, and the 

 food we eat. All of these are various forms 

 of matter. Two basic particles make up the 

 composition of all matter — the atom and the 

 molecule. The molecule is the smallest particle 

 into which matter can be divided without 

 destroying its characteristic properties. In 

 physics, the molecule is the unit of matter. 

 Molecules are composed of one or more atoms. 

 The atom is the smallest particle of certain 

 kinds of matter called chemical elements. 



A compound is a substance (or matter) 

 formed by combining two or more elements. 

 Thus, ordinary table salt is a compound formed 

 by combining two elements — sodium and chlorine. 

 Elements and compounds may exist together 



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