The characteristics of the atmosphere vary widely with altitude. The density of air decreases with increasing altitude due to the gas laws and gravity. As a result more than 99% (by mass) of the atmosphere is found in the first 30km of the atmosphere. The atmosphere is split into several layers (strata) each of which has specific, characteristic physical and chemical properties. The layers are formed due to temperature and density relationships. The chemical properties determine the reactions that occur in the strata. The diagram below shows the strata in the atmosphere.
From Microsoft Encarta '98 deluxe CD-ROM
The next page gives details of the different strata in the atmosphere as shown above.
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