Atmospheric Resources

The atmosphere around earth is a blessing of nature on earth to have permitted the existence of life on it. Earth is endowed with an excellent resource of atmosphere - both to shield it from sun's harsh rays and other ill effects of celestial bodies as well as to provide the basis of life on earth.

Atmosphere above the earth forms part of carbon cycle, part of oxygen cycle and part of nitrogen cycle along with earth's surface.

These three cycles supply and replenish carbon dioxide, oxygen and nitrogen. Thereby the living has been possible on earth. Of course, hydrological cycle is also shared by atmosphere.

The atmospheric resources include:

Air

Air around earth is not uniform throughout the atmosphere. The density of air is gradually reduced with altitude. Although atmosphere is spread to 200 km around earth, the oxygen content beyond 5 km above surface of earth hardly supports any life. The composition of air substantially differs in different layers of atmosphere. At the surface of the earth it has 78% N, 21% O₂, 0.03% CO₂. This composition is maintained by various natural cycles. If the composition of atmosphere changes for any reason, substantial changes are expected in natural cycles such as carbon, oxygen, nitrogen and hydrological cycles.

Atmospheric temperature

The atmospheric temperature governs the type of biodiversity, fertility of soil, the hydrological cycle and many other abiotic and biotic parameters of our planet. It acts as a resource - in the sense that optimum temperature promotes the production and productivity of many natural resources, such as plants, animals and microbes. Adverse temperature may also act as deterrent to production and propagation of these natural resources.

Rainfall and Its Pattern

The rainfall and its characteristics is one of the widely studied subjects in climatology. Success or failure of rainfall not only affect the hydrological resources like surface resources (river, stream, ponds) and underground resources of water but also decides the growth of entire plant community including crops and forests. Rainfall decides the living of entire animal kingdom too, as all the animals depend on crops and forests. The extent of rainfall, number of rainy days, rainfall density, its distribution and many other rainfall related characters are of importance.

Sunshine

The greatest resource of atmosphere is sunshine. Although less than 1% of sunshine received by earth is used for photosynthesis, sunshine is of utmost importance, because it forms the basis of food production. Without sunshine - there would not have been life at all. Sunshine is also the primary reason to heat the atmosphere. Hence, atmospheric temperature is governed by sunshine. Sunshine is the primary cause of evaporations and therefore hydrological cycle is governed by sunshine.

But, sunshine can be dangerous. It is safe now at surface of earth because it is passing through the ozone layers - where most ultraviolet rays are filtered. If, entire sunshine is received on the surface - without such filtration - it can lead to many hazardous consequences on human health and plant and animal life.

The utility of atmosphere resources such as oxygen, sunshine, temperature can hardly be quantified. The living and production of entire autotrophic biosphere and indirectly entire terrestrial biosphere is governed by these three resources. Oxygen resource is directly responsible for life in the entire biosphere.

Sunshine

India is a tropical and subtropical country with a latitudinal position between 8^o M to 32^o M. As compared to Western countries, we are bestowed with fairly good sunlight almost during the entire year. Average sunshine hours available in different parts of our country varies from 8 hours to 13 hours during different months. In South, the variation is narrow and in most months it is between 11 to 12 hours / day. But in hilly regions and towards higher latitudinal areas, the sunlight period is restricted to 7 - 10 hours / day. In other parts of the world, the variations are wide.

Temperature

Being tropical and subtropical in its climate, India has been enjoying good temperature in its atmosphere. Temperature is considered as a resource because in most temperate countries low temperature during most of the period of year acts as a major constraint for crop production, microbial activity etc.

In India, the atmospheric temperatures vary from 22^oC to 43^oC during most parts of the year except winter months (December to April). In winter months temperatures vary from 5^oC to 20^oC. Coldest months are normally January and February. In small parts of Himalayan region the atmospheric temperatures are harsh to the tune of - 10^oC in winter months. Similarly, in small western parts of Rajasthan and Gujarat the summer temperatures are as high as 45^oC and extend to several months.

In most other parts of country, the atmosphere has showered us with good temperatures during most parts of the year. This has made it possible to grow large number of crop species, besides allowing larger bio-diversity in plants and animals.

Rainfall

As compared to many other parts of world, the rainfall received in India is adequate, widespread and more favourable to grow agricultural crops and maintain larger biodiversity. A highly favourable rainfall situations has been responsible for large number of varying eco-systems - which have favoured widely varying bio-diversity in different parts of country.

India is known to have a region of highest rainfall in world (with 6000 mm annual rain in Cheerapunji) as well as one of the worst drought areas of world (Rann of Kutch which receives as less than 50 - 60 mm rain once in 5 - 6 years).

Indian rainfall resources are due to receipt of

• South West monsoon from May to September (Known as Kharif) as well as

• North East monsoon from October to December months (Known as Rabi).

In general, contribution during south west monsoon is to the tune 60 -65% of total rainfall received and 25 - 30% of total rainfall is received during North East monsoon.