Layers of atmosphere of earth
Layers of atmosphere of earth are listed below.The study of atmosphere provide us the knowledge about significance of gases present in the air. There are four main layers of atmosphere.
Environment
The study of environment provide us knowledge about our surroundings and activities of human on it. Due to human activities our atmosphere is changing day by day
Atmosphere 
The study of composition of atmosphere provide us the knowledge about significance of gases present in the atmosphere.
Definition
Atmosphere is the envelope of different gases around the earth.
Atmosphere extends continuously from the earth surface outwards without any boundary. About 99 percent atmospheric mass lies within 30 kilometers of the surface and 75percent lies within the lowest 11kilometers.
Composition of dry air
Nitrogen 78.09 percent by volume
Oxygen 20.94 percent by volume
Argon 0.93 percent by volume
Carbon dioxide 0.03 percent by volume
Layers of atmosphere
Atmosphere consist of four layers;
1. Thermosphere
2. Mesosphere
3. Stratosphere
4. Troposphere
These four spheres extend from the earth upwards.
Change in temperature and pressure
The concentration of the component gases decrease gradually upwards, and which results in gradual decrease of pressure. But temperature of the atmosphere does not change in a gradual way. It varies in a complex way. Depending upon the temperature variation, atmosphere divided into four region.
Troposphere
Temperature decrease from 17 degree to 58 regularly in the lowest layer extending up-to 12 km. This layer of atmosphere called troposphere.
Stratosphere
Above troposphere lies the stratosphere that extends upto 50km.And In this layer temperature rises upto 2 degree.
Mesosphere
Beyond the stratosphere lies the Mesosphere, and it covers upto 85km. In this region again temperature decreases down to _93 degree C.
Thermosphere
Beyond 85km lies the Thermosphere, in which temperature goes on increasing upwards.
Characteristic of troposphere
Decrease in temperature
Although concentration of carbon dioxide and water vapours is negligible in atmosphere, yet they play a significant role in maintaining temperature of the atmosphere. And both of these gases allow visible light to pass through but absorb infrared radiations emitted by the Earth’s surface. Therefore, these gases absorb much of the outgoing radiations and warm the atmosphere. As the concentration of gases decrease gradually with the increase of altitude, and correspondingly temperature also decrease at rate of 6 degree per kilometer. This is region where all weathers occur.
Characteristic of stratosphere
In this region, temperature rises gradually up to 2 degree C. The presence of ozone in this region is responsible for the rise of temperature in stratosphere, and within this region, temperature increases as altitude increases. Such as lower layer temperature is about _58 degree and upper layer is about 2 degree C.
