9th Class Science Natural resources Role of Atmosphere in Climate Control

         Introduction

The resources which are provided to us by the nature are called natural resources. Earth is the only planet where life exists. This is because of the fact that the conditions on the earth surface is favorable for the existence of life. The natural resources of the earth are land, water and air. Water covers 75% of the earth's surface and air forms the blanket over the surface of the earth called atmosphere. All the components atmosphere, lithosphere and hydrosphere together constitute biosphere. There are two components of ecosystem, biotic and abiotic components. The biotic components include living organisms like plants and animals where as abiotic components include air, water and land. The status of complexity and interdependence among the various components of the environment is due to the perfect and systematic cycling of various chemical that is water, oxygen, carbon and nitrogen.

Our physical environment is formed by various nonliving things around us. They play very important role in the growth and development of the living components. For example, the plants prepare their food by the process of photosynthesis using sunlight, water and carbon dioxide and animals derive its food from plants in the process. There is change in temperature, pressure, humidity, rainfall etc of a particular place and these components constitutes the weather condition of a place. The average weather condition of an area constitute the climate. The most important factors of climate is temperature and seasonal variations of a region.

      Role of Atmosphere in Climate Control

Air is one of the important natural resources and no life will be possible without air. The atmosphere forms a blanket over the surface of earth and maintains the variation of temperature and pressure on the earth during days and nights.

It helps to keep the temperature of earth at optimum for the survival of life. It do not allow the drastic variation of temperature during days and nights. If there would have been no atmosphere, then there would have been a drastic change in temperature during days and nights, as in the case of moon where temperature varies from - 190°C to 110°C.

            Movement of Air (Winds)

The movement of wind is due to the difference of pressure in the lower layer and upper layer of the atmosphere, on land and water bodies. Some time strong breeze and some time gentle breeze blow in the atmosphere. All these phenomenon is the result of change that takes place in the atmosphere due to pressure difference on land and water bodies.

When solar radiation falls on the earth, some are absorbed. But most of them are reflected back into the atmosphere by the land and water bodies. These reflected radiation heat up the lower layer of the atmosphere, as a result convection current sets up in the air. But since the land get heated faster than the water bodies, the air over the land also gets heated and create a region of low pressure on land. Thus, wind moves to the region of lower pressure over land from the region of high pressure on the water bodies and create winds. During day time the wind blow from sea to land and during night the process is reversed, as the wind blow from land to sea. This temperature difference across the earth generates the development of major wind belt over the earth surface, which forms the climatic zone of the world. Apart from this, the various other factors that influence the movement of wind is the rotation of the earth and the presence of mountain ranges in the path of the wind.

            Rain

When the water bodies heates up during the days, the upper layer of the water bodies change into the vapour and goes up in the atmosphere with the air. As these air reaches the upper layer of the atmosphere it expand and cools. On cooling these water vapours get condensed in the form of tiny droplets of water, in the upper layer of the atmosphere. When these collection of water vapour became heavier and bigger, it fall down on the earth surface in the form of rain, snow, or hail.

The rainfall pattern is decided by the prevailing wind pattern, in the country like India, the rain is mostly brought by the southwest or north east monsoons.

The south west monsoon blows from sea to land during the month of April and May. Local rain in coastal regions are caused due to sea breezes and rains in the great topographic relief are caused by mountains and valley breezes,

         The term used to identify the living components of the environment is:

(a) Biotic

(b) Abiotic

(c) Topographic

(d) Ecosystem

(e) None of these

Answer (a)

     What is the range of temperature of the surface of moon?

(a) \[-{{180}^{o}}C\] to \[{{100}^{o}}C\]

(b) \[{{170}^{o}}C\] to \[{{100}^{o}}C\]

(c) -190°C to 110°C

(d) -170X to 12CTC

(e) None of these

Answer: (c)

       The species of certain plants and animals which are present within certain region or area is called:

(a) Zooplankton

(b) Biota

(c) Phytoplankton

(d) Kingdom

(e) None of these

Answer: (b)