Question: ) what separates the troposphere and stratosphere ??
Answer: The troposphere is bonded on the top by a layer of air called the tropopause, which separates the troposphere from the stratosphere, and on bottom by the surface of the Earth.
Explanation: Troposphere:
It is the lowermost and densest layer of the atmosphere. It spreads till a height of about 8 km over the pole but over the equator, it is 18 km. About 80 percent or more of the total mass of the atmosphere lies in this layer. With increase in height, the temperature keeps on decreasing till the limit of this layer. This is said to be the normal lapse rate. On an average, the decrease in temperature with height is 60 Celsius per km. The upper boundary is known as the troposphere , placing between 8 and 18 km. At this level, the average temperature spreads to minus 500 to minus 600 Celsius. Water vapour is available in this layer in plenty and about 99 percent of the total atmospheric water vapour is focused here but wide variation is seen in terms of height and longitudes. Vapour plays a very vigorous role in regulating the temperature of the earth by producing greenhouse effect.
Stratosphere:
The Stratosphere is the upward second layer as well as the middle layer of the atmosphere. It starts from tropopause to approximately a height of 50 km. The temperature at the tropopause remains nearly constant till the height of 20 km. After that, it starts increasing and continues to increase till the height of 50 km. At this level, the projected temperature is about minus 100 to minus 150 Celsius. Though the temperature is on advent, there is no atmospheric turbulence. This layer is completely free from clouds and other weather settings.
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