Atmosphere-Weather-Climate in this basic and important article of climatology we will study definitions of atmosphere, features of atmosphere, also we will know about effects and importance of atmosphere, along with we also discussed here about weather and climate which is crucial concept of climatology to know other major concept, we also know factors affecting weather and climate etc..
Atmosphere: Features, Effects, Importance | Weather & Climate & Factors Influencing weather & Climate
Table of Content
- Definition of Atmosphere
- Features of Atmosphere
- Effects of the Atmosphere
- Importance of Atmosphere
- Weather and Climate
- Factors affecting Weather & Climate
“Atmosphere is a mixture of different gases.” These gases are spread all around the earth to a great height like a thick cover. The atmosphere is held to earth’s surface by the force of gravity. On account of atmospheric shield around earth life on earth has also become possible. Otherwise earth like its neighbour moon would have been like a rocky desert without life.
Definition of Atmosphere
“The atmosphere is a mixture of gases which entirely envelopes the earth to a great height.”
According to a meteorologist H.J. Critchfield “The atmosphere is a deep blanket of gases and liquid and solid particles suspended in it which entirely envelopes the earth. The entire surface of earth is covered equally by atmosphere.”
Some Features of Atmosphere
(i) The air of atmosphere is colourless, odourless and tasteless.
(ii) It has momentum, it is wet at lower levels and is compressible.
(iii) It can be felt when air moves. Moving air is called wind.
(iv) Air has weight. Its pressure is felt on the surface. It is called air pressure by meteorologists.
(v) Air pressure is measured in millibars (Mb) or hactopascal.
(vi) The pressure at sea level is 1013.25 Mb. The air pressure goes on decreasing with height and remains changing with changing seasons.
(vii) The highest air pressure recorded till date is 1079 Mb and the lowest 877 Mb.
Effects of the Atmosphere
(i) It does not allow full solar radiation to reach on the surface of the earth and keeps the earth safe. It acts as a vast sieve around earth filtering out all harmful objects. It stops harmful ultraviolet radiation. It allows entry to some radiations to keep the earth and bottom layers of atmosphere warm. It is the reason why earth does not get extremely hot during day time.
(ii) The carbon dioxide and water vapour found existing in atmosphere at lower levels absorb terrestrial radiation and reflect it back at night to keep the earth warm. It is called Green House Effect.
(iii) Due to differential heating of atmosphere, there are differences in temperature over earth. This generates horizontal movement of air known as wind. As a result precipitation (rainfall, snow, hail) also takes place.
(iv) On account of differences in temperature and rainfall during different seasons plant and animal life is also influenced.
(v) It makes radio broadcasting possible.
(vi) It protects earth from attack by meteorites.
(vii) Flying of aeroplanes is possible because of the atmosphere.
Importance of Atmosphere
1. It is the foundation of life.
2. Climate and weather changes take place in atmosphere.
3. Moderates temperature.
4. Makes radio broadcasting possible
5. Saves earth from meteorites
6. Saves life on earth from ultraviolet rays.
Weather and Climate
Weather:.The day-to-day or even shorter period condition of atmosphere with respect to its elements temperature, pressure and other. elements at any place or time.
Climate:The general weather conditions over a long-period and larger area. It shows the character of atmospheric conditions at any place.
Climate is not represented by the average weather condition. This is an old term and meaningless concept. Climate must not only represent the average conditions but must also show the extremes that affect the people. The deviation from averages should also show the extremes and other changes in atmosphere taking place.
The state of atmosphere can be described by its physical condition. It describes the condition of atmosphere at any definite place or time. The chief elements of weather and climate are:
(ii) Air pressure
These elements are important because of their predominance worldwide. The distribution of these elements leaves their impact on weather and climate in one form or the other. They are chiefly distributed horizontally throughout the globe from Equatorial to Polar Regions or vertically from ground level to upper layers of atmosphere.
The temperature expresses the intensity of heat at any place or in other words it also shows relative warmth or coldness of the atmosphere.
All the energy of the earth is obtained from insolation. The solar radiation received on earth from the sun is called insolation. It leaves great impact on other elements of temperature. On account of differential distribution of insolation, there are also differences in air pressure on earth and on account of differences in air pressure winds are originated. The movement of air horizontally from high pressure to low pressure areas is known as wind. Winds blow parallel to ground level and their speed depends on the differences in air pressure.
Humidity:Humidity is present in atmosphere in the form of water vapour. When favourable conditions exist or when air is saturated condensation takes place. Humidity upon taking the form of condensation originates clouds and precipitation can occur only when there are clouds in the sky. Precipitation can be in the form of rain, snow, sleet or hail. At lower levels water vapour are present in different quantities in air. The capacity of air to absorb water vapour is controlled by temperature. When temperature increases, the capacity to hold water vapour also increases. When temperature decreases, its capacity to hold water vapour also decreases. Consequently, the air sheds its extra load of water vapour. Generally, the air has low capacity to hold water vapour at higher altitudes because of temperature decrease. Consequently, the condensed droplets of vapour take the form of clouds which upon rising form bigger drops by joining of many tiny droplets together. The earth’s gravity then acts on these droplets. Due to gravity the air cannot hold these droplets and they fall to earth as precipitation.
It is clear from the above description that temperature is the basis of all other elements of weather and climate. Not only this, it also establishes inter-relationships between these different elements of weather and climate.
Factors affecting Weather & Climate:
The elements of climate vary from place-to-place and from time to time. These elements are controlled or influenced by the following factors:
(i) Latitudes or insolation.
(ii) Altitude (from sea level).
(iii) Relief features.
(v) Atmospheric pressure.
(vi) Air masses and winds.
(vii) Various types of storms, cyclones etc.
(ix) Natural vegetation and soil.
All these factors influence temperature and precipitation. The influence can be either through one or more elements but their combine impact determines weather and climate.