What Causes Monsoon?
Monsoon is actually an annual phenomenon of the weather. This phenomenon originates from the earth’s rotation in respect to the sun. Monsoon winds are annual, but it is impossible to predict their duration, quantity of rain and timings of strike. Because of this reason storm prediction is not possible in the areas which come under the impact of monsoon.
Causes of monsoons
Monsoons originate from the difference between the temperatures of sea and land. Actually land reflects the rays of sun, which causes heating of the air present over the land. Now water sources (oceans) are able to absorb this heat from air, as a result air present at the top of oceans remains relatively cooler. This fact is important for the zone of Asia, because major part of Northern Hemisphere is land but southern hemisphere is ocean. In the season of summers, earth makes a perfect angle with the sun. As a result, direct sun rays strike on the land of Northern Hemisphere. Reflection of the hot sun rays causes warming of the air of northern hemisphere. This hot air rise up in the atmosphere, as a result cooler air (southern hemisphere) from the ocean rushes to the fill the gap. This cool air also brings moisture along with it. And this moisture is the reason of summer rains in the Asia. This phenomenon is known as southwest monsoon or summer monsoon. This cycle goes on, because when the moisture filled cool air causes rain, loss of moisture and energy takes place. This causes heating of air. This hot air then rises in the atmosphere and return back to the ocean, where it again losses heat and get filled up with enough moisture. After this it rushes back to the Northern Hemisphere to again replace the warm air of the land, this causes raining again. It happens in every season of summer. Monsoon winds are the major sources of rain in many countries of south Asia.
One more monsoon exists, which is named as northeast monsoon or winter monsoon. It strikes in the winter season, when sun rays are stronger at southern hemisphere. In the winter season, lands are much cooler than the oceans. So, in this case “reverse summer monsoon” takes place. As a result air reverses its circulation. Warm air moves from oceans to land and cold air (cold surges) moves from land to ocean. This cold surge entrap the moisture when it passes over the tropical waters in order to release it over the northern Australia, Indonesia, Indian coast and Sri Lanka.
Importance of monsoon winds
Monsoon winds are extremely important for the countries of south Asia (especially India), because it is the major source of rain in these zones. In fact, whole economy of some agriculture based countries (like India) is depending upon accurate strike of monsoon winds. In monsoon dependent countries, if monsoon winds strike before the time then they causes severe floods and if they are not punctual (late) then it causes conditions of severe droughts. So, it can be concluded that monsoon is the backbone of agriculture based economy of South Asia.