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STRUCTURE OF THE ATMOSPHERE, , 1.The atmosphere consists of different layers with, varying density and temperature., , 2. Density is highest near the surface of the earth and, decreases with increasing altitude., , 3.The column of atmosphere is divided into five, different layers depending upon the, , temperature condition., , Name the layers of atmosphere, , They are: troposphere, stratosphere, mesosphere,, thermosphere and exosphere., , The troposphere, , 1.It is the lowermost layer of the atmosphere., , 2. Its average height is 13 km, , 3. extends roughly to a height of 8 km near the poles, and about 18 km at the equator., , 4. Thickness of the troposphere is greatest at the, equator because heat is transported to great heights, by strong convectional currents., , 5. This layer contains dust particles and water vapour., 6. All changes in climate and weather take place in, this layer., , 7. The temperature in this layer decreases at the rate, of 1 °C for every 165 m of height., , 8. This is the most important layer for all biological, activity., , 9. The zone separating the troposphere from, stratosphere is known as the tropopause., , The air temperature at the tropopause is about minus, 800 °C over the equator and about minus 45° C over