Physical Geography GEOGRAPHY 1710 Chapter 3 DAVID R SALLEE Earth s Modern Atmosphere Atmospheric Profile z z z Atmosphere extends to 32 000 km 20 000mi from surface Exosphere Exosphere s top is at 480 km 300 mi Three criteria to examine atmosphere Composition Temperature Function Atmospheric Pressure Figure 3 2 Atmospheric Composition z Homosphere atmosphere inner Surface to 80 km 50 mi Gasses evenly blended z Heterosphere atmosphere outer 80 km 50 mi outwards Layers of gasses sorted by gravity Figure 3 3 1 Atmospheric Temperature z Troposphere Surface to 18 km 11 mi 90 mass of atmosphere Normal lapse rate average cooling at rate of 6 4 6 4 C km 3 5 3 5 F 1000 ft Atmospheric Temperature z Stratosphere 18 to 50 km 11 to 31 mi z Mesosphere 50 to 80 km 30 to 50 mi z Thermosphere Roughly same as heterosphere 80 km 50 mi outwards Atmospheric Function z Ozonosphere Part of stratosphere Ozone O3 absorbs UV energy and converts it to heat energy z Ionosphere Absorbs cosmic rays gamma rays XX rays some UV rays Variable Atmospheric Components z Natural Sources z Natural Factors That Affect Air Pollution z Anthropogenic Pollution 2 Natural Factors That Affect Air Pollution Temperature Inversion z Winds z Local and regional landscapes z Temperature inversioninversionSituation where a layer of warmer air exists above the Earth s surface in a normal atmosphere where air temperature decreases with altitude In the warmer layer of air temperature increases with altitude Figure 3 9 Pollution Sources Anthropogenic Pollution Caused by Humans z Carbon monoxide z Photochemical smog z Industrial smog and sulfur oxides z Particulates Photochemical Smog Figure 3 10 Photochemical smog is a condition that develops when primary pollutants oxides of nitrogen and volatile organic compounds created from fossil fuel combustion interact under the influence of sunlight to produce a mixture of hundreds of different and hazardous chemicals known as secondary pollutants Figure 3 14 3
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