It is generally stated that India is dependent on agriculture. Our economy is mostly based upon agricultural products. Agricultural land need irrigation. Irrigation in our country, is mostly depends upon the rains which take place during the monsoons. Therefore, if monsoon gets angry with us in India, it hampers our economy very badly. This year we could not have a good monsoon. In Karnataka, Government is distributing funds to the temples in order to please the god of rains. Stock market is shrinking and economy of the country is showing depressing signals. Therefore, it is very important to know as to what really the monsoon is and how it is so very important.
What is monsoon?
The word monsoon is derived from the Arabic word mausim meaning season. The most famous monsoon is the Indian monsoon. The intense rainfall in these regions can cause massive flooding and destruction of crops. In dry climates, monsoons are an important replenishment for life as water is brought back into drought-stricken zones of the world. Part of the reason India gets such an intense monsoon season is due to its elevation. The higher the land mass, the higher the likelihood of the development of a low pressure zone. The Tibetan Plateau to the north of India is one of the largest and highest plateaus on Earth.
The earliest explanation for monsoon development came in 1686 from the English astronomer and mathematician Edmond Halley.
Halley is the man who first conceived the idea that differential heating of land and ocean caused these giant sea-breeze circulations. As with all scientific theories, these ideas have been expanded upon.
During most of the year, winds blow from land to ocean making the air dry. Winds originating from land are called continental.
During certain months of the year, the winds begin to blow from the ocean to the land making the air moist. Winds originating over a body of water are called maritime.
This moist ocean air is what causes monsoonal rains over many countries.
Why Do Wind Patterns Shift in a Monsoon?
Differential heating occurs when the sun heats the land and oceans. Incoming solar radiation heats landmasses faster than large bodies of water. In tropical and sub-tropical climates, solar heating is most intense in the summer months. As the land heats throughout the summer, a large low pressure system builds over the land. The heat from the sun also warms the surrounding ocean waters, but the effect happens much more slowly due to the high heat capacity of water.
Therefore, the ocean temperatures as well as the layer of air above the oceans stays cooler longer. The cooler air above the oceans is moist and more dense creating a high pressure zone relative to the pressure above the landmass.
Winds flow from high pressure areas to low pressure areas due to the pressure gradient. Once the temperature conditions on the land and oceans change, the resultant pressure changes cause the winds to change from a land-to-ocean direction to an ocean-to-land direction. Monsoon season does not end as abruptly as it begins. While it takes time for the land to heat up, it also takes time for that land to cool in the fall. This makes monsoon season a time of rainfall that diminishes rather than ends.
Monsoon seasons can actually fail bringing intense drought and famines to many parts of the world. From 1876-1879, India experienced such a monsoon failure. To study these droughts, the Indian Meteorological Service (IMS) was created. Later, Gilbert Walker, a British mathematician, began to study the effects of monsoons in India looking for patterns in climate data. He became convinced that there was a seasonal and directional reason for monsoon changes.
It is a natural supposition that there should be in weather free oscillations with fixed natural periods, and that these oscillations should persist except when some external disturbance produces discontinuous changes in phase or amplitude. According to the Climate Prediction Center, Sir Walker used the term 'Southern Oscillation' to describe the east-west seesaw effect of pressure changes in climate data. In the review of the climate records, Walker noticed that when pressure rises in the east, it usually falls in the west, and vice versa. Walker also found that Asian monsoon seasons were often linked to drought in Australia, Indonesia, India, and parts of Africa.
Jacob Bjerknes, a Norwegian meteorologist, would later recognize that the circulation of winds, rain, and weather were part of a Pacific-wide air circulation pattern which he called as "Walker circulation".
New Theories on the Causes of Monsoons
Theories of the development of monsoons have stood firm for over 300 years. Classical thinking on monsoons is that their development is sparked by the differential heating of land and ocean as described above. But in a recent NASA Earth Observatory release, those ideas may be changing. Geoscientists at the California Institute of Technology have been working on new ideas as to exactly why monsoons develop.
Two researchers, Schneider and Simona Bordoni of the National Center for Atmospheric Research in Colorado, used computer models to re-create an Earth with no landmasses. Surprisingly, they found that differential heating was not a necessary component to creating monsoons. Instead, they concluded monsoons arise because of an interaction between tropical air circulation and large-scale turbulence in the middle latitudes. The large middle latitude disturbances modify circulation in tropical regions causing rapid circulation changes which can bring on the characteristic high surface winds and heavy rainfall of the monsoon.
Whatever may be the causes and effectsof the monsoons, the important thing is that anger of monsoons can create havoc in the country. Therefore, it is very crucial for our meteorological department to devise a system whereby we can predict the monsoons in advance and more accurately so that we could curb some of the ill effects of a bad monsoon.
It is not the blistering heat that is keeping the farmers away from their land of a little over an acre (0.4 hectares). Most Indian farmers have no access to irrigation systems. They depend on the monsoon rains that fall between June and September. This year the rains have not come. "No rain, nothing," says Sharmila, as she flicks away flies with the edge of her scarlet sari. The family has been unable to plant its main sorghum crop, she says, and their buffaloes are becoming "diseased", a euphemism for starving.
India is experiencing its worst monsoon in years. Summer rains constitute around 80% of the country's annual rainfall. But from June to mid-August, when most crucial planting takes place, the rains were 29% lower than average. In Uttar Pradesh, they were down by more than 60%. Rice, the biggest crop sown during the monsoon, has been worst affected, along with sugar cane and oilseeds. Rainfall has increased in some areas in recent days. But it has come too late for many crops, which require an even sprinkling through the hot summer. Heavy showers now could even damage already reduced crops of sugar cane.
Fresh rainfall may prove more helpful to winter-sown crops such as wheat, which rely heavily on water from reservoirs, whose levels remain far below average.
To mitigate the damage from the poor monsoon, the government is encouraging farmers to plant more winter crops. India's economy is closely tied to its fickle summer rains. Agriculture accounts for 18% of GDP. More importantly, it employs 60% of Indians, many of whom now seem certain to curb their spending this year. A bad monsoon can also reduce power production: hydropower provides a quarter of India's electricity.
In 2002, when monsoon rains were down by 19%, GDP growth slowed from 5.8% to 3.8%. But as agriculture shrinks as a proportion of GDP—it made up 30% in 1990—the impact of poor monsoons is reduced. This year industrial output in June surged by its highest annual rate in 16 months, nearly 8%. Still, many economists have shaved a percentage point off growth estimates for the year, to between 6% and 7%. The government, meanwhile, has said it has enough food stockpiled from two years of healthy harvests to prevent high inflation. Let us pray to the god of rains for better monsoon management so that the anger of monsoons may be cooled down.