Geography-Class-4-24.07.2021

 LAYERS OF ATMOSPHERE

In today's class, there was a continuation on layers of the atmosphere from the stratosphere , about weather and climate and solar radiation.

STRATOSPHERE:

• Also called as ozone layer.
• It extends upto 50 km
• The temperature of the layer remains increasing due to absorption of UV radiation.
• It is the ideal layer for air transports because of absence of turbulence.(Vertical mixing of air)
• Ozone hole is predominant in Antarctic region because of the presence of stratospheric clouds.
• Helps in survival by filtering harmful UV rays.

MESOSPHERE:

• Coldest layer (maximum drop -100 deg C).
• Burning of meteoroids takes place due to atmospheric friction.
• Noctilucent clouds appear due to very low temperature.

THERMOSPHERE:

• Ionosphere+Exosphere
• There is a constant increase in temperature.

IONOSPHERE:

• 400km above the earth surface.
• Presence of huge clumps of Fe.
• Interaction between solar wind and earth’s magnetic field results in aurora (colorful light) formation.
• The ISS is placed around 280km in this layer.
• Reflection of  transmitted radio waves to earth’s surface occurs in this layer. 
• Aurora in north pole- Aurora Borealis
• Aurora in south pole- Aurora Australis

EXOSPHERE:

• Present above 400 km from earth’s surface.
• The layer above 400km gradually mixes with the outer space.
• It has very rarified contents.

TEMPERATURE VARIATION IN ATMOSPHERIC LAYERS:

TEMPERATURE VARIATION IN ATMOSPHERIC LAYERS:

                  

WEATHER AND CLIMATE:

                      
 In general, weather means what we get and climate is what we expect.

WEATHER	CLIMATE
The day-to-day information of the atmosphere which changes over a particular area in a specific time.  Changes frequently. The atmospheric elements of weather are   Air pressure  Humidity  Temperature  Rainfall These can affect the weather over a short time. Eg: British Islands (no climate)	Statistical information of average weather condition for a specific region more than 30-35 years. Does not change frequently. The same atmospheric elements of weather are observed over the decades and thus affect the conditions of climate. Eg: In Egypt, there remains same temperature and pressure throughout the year.(No weather)

SOLAR RADIATION AND HEAT BUDGET:

• Solar radiation is a short wave from the sun.
• E=hv = hc/λ
• E is inversely proportional to λ.
• Wavelength(λ) is made small so that it travels the entire solar system.
• Not all radiation reaches earth but, without solar radiation there is no life on earth.
• Radiation from sun to earth- short wave
• Radiation from earth to sun- long wave(terrestrial radiation wave)

Heat budget will be continued in the next class.

Credits:Leo Rajalakshmi