Atmospheric Temperature

CONTENTS AMOSPHERE THE COMPOSITION OF THE STRUCTURE OF ATMOSPHERE FACTORS EFFECTING TEMPERATURE GLOBAL DISTRIBUTION OF TEMPERATURE

INTRODUCTION • The Sun is the main source of heat and light on the Earth. • The Earth is enveloped by a blanket of atmosphere which protects from the harmful radiation of the Sun. • The atmosphere acts as a huge filter keeping out all harmful ultra violet radiation while allowing heat to reach the Earth.

ATMOSPHERE This is the layer of gases surrounding the earth. Earth’s atmosphere is a colourless, odourless, tasteless Sea of gases, water vapour and fine dust. It is about 700 miles deep.

THE COMPOSITION OF THE STRUCTURE OF ATMOSPHER TROPOSPHERE STRATOSPHERE MESOSPHERE THERMOSPHERE IONOSPHERE EXOSPHERE

TROPOSPHERE

The lowest layer of the atmosphere is called troposphere. It extends 12km above the ground. It contains 70percent of all the atmosphere’s gas, water vapour and dust.

STRATOSPHERE •

It is 50km above the Earth’s surface . • It contains 19 percent of the atmosphere’s gas . • There are little water vapours in this layer. OZONE LAYER ,a band of ozone gas that absorbs the Sun’s harmful ultraviolet rays also present in this layer.

MESOSPHERE •

This layer is 80km above the ground. • The gases in the mesosphere are too thin to absorb much of the Sun’s heat, so temperature drops rapidly with the height.

THERMOSPHERE •

The layer of the atmosphere above th mesosphere. • The gases of the thermosphere are even thinner than those in mesosphere ,but they absorb ultraviolet light from sun, boosting temperature to as high as 2000ºC. • This layer protects us from Meteors as they burn up due to high temperature.

IONOSPHERE •

This layer is full of electrically charged particles . • The ionosphere is important for communications because around the world all communications are transmitted through this layer.

EXOSPHERE •

The exosphere is the outer layer of th atmosphere. • It is more than 700km above the earth where gases get thinner and thinner and drift off into space.

FACTORS EFFECTING TEMPERATURE • • • • • • •

Latitude Altitude Distance from sea Oceans currents Winds Slopes of land Vegetation

LATITUDE The land near the equator is always hot all year round and the poles are always cold. This is so because on the equator the rays of the sun fall vertically. The places away from the equator are less hot.

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ALTITUDE As we go higher up the temperature goes on decreasing .On climbing every 166 meters there is a fall of 1C in temperature.

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DISTANCE FROM THE SEA The places near the sea have moderate temperature all year round. SEA BREEZE During day the air above the land expands due to heat and rise up, cool air from the sea blows towards land. It cools land during day. LAND BREEZE. At night the land cools quickly. The air above water expands and rises up, cool air from land blows over sea

A cool breeze blowing from sea towards Made by-land IQBAL KAUR (S. S.

A cool breeze blowing from land towards sea during night

OCEANS CURRENT • Oceans currents also affect the

temperature of a place These oceans currents may be warm or cool. • When the winds blow over warm currents, they collect water vapours and moisture and cause rainfall on the coasts.

WINDS The winds coming from hot areas lower the temperature in winter and rise it in summer. Whereas winds blowing from sea rise the winter temperature but lower the summer temperatures

SLOPES OF THE LAND In Northern hemisphere slopes facing south are warmer than north facing slopes and in the Southern hemisphere, north facing slopes are warmer than south facing slopes.

VEGETATION Vegetation reduces temperature by releasing moisture in the air. That is why tree covered area are cooler. Vegetation also helps in increasing the rainfall of a place.

GLOBAL DISTRIBUTION OF TEMPERATURE • • •

TORRID ZONE TEMPERATE ZONE FRIGID ZONE

TORRID ZONE This zone lies between 23ºNand 23ºS latitudes. Here the sun’s rays are almost vertical all through the year because it receives

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TEMPERATE ZONE

This zone lies between 23ºN and 66ºN latitudes in the northern hemisphere and 23ºS and 66ºS in the southern hemisphere. In this zone the amount of heat received decreases with an increase in latitude. This zone is comfortable for live in and work.

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FRIGID ZONE This region lies between 66ºN to north pole and 66ºS to south pole. Here the rays of sun are always slanting and thus the place is always cold. We find very few people living in this zone.

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BIBLIOGRAPHY • N.C.E.R.T. BOOKS