Monsoon - Weather informations

Monsoon

Monsoon is a kind of reversing seasonal wind that changes its direction in the course of the year. The change in the direction of those winds brings also the change in the precipitations in a certain region. That is why there are two types of monsoons –dry (winter) monsoons that usually blow from the land to the sea and summer monsoons which bring humidity from the ocean to the land. The English word monsoon has an Arabic origin (mawsim) - means ‘season’. Most of the summer monsoons have a westerly component in their direction .Winter monsoons on the other hand have strong easterly component and often cause drought over the land. There are three main regions in the world where the monsoons are distinct phenomena-West Africa, Asia and Australia. Monsoonal areas are all those areas in the world that receive more rain in one particular season. Following this criteria other parts of the world can be classified as monsoonal areas also-such as parts of North and South America and even Europe. Monsoons are nothing more than large-scale sea breezes. They are created from the difference of pressure of the land masses and the sea. This difference in pressure occurs because the land and the sea are heated to a different extent. The air over the land warms much faster than the air over the sea. The hot air rises and creates an area of low pressure over the land. This produces a wind that blows from the sea to the land and transports the moisture from the oceans with it. When this humid air travels over the land and reaches a mountain, it lifts and cools. That cooling produces condensation and heavy rains occur. In the winter the land is cooled more quickly than the sea and the winds begin to blow from the land to the sea.

Monsoons in different parts of the world

Monsoons in Africa: This type of monsoon is born from the difference in pressure and humidity between the equatorial parts of the Atlantic Ocean and the Sahara desert. In February it starts its movement from the equatorial Atlantic and reaches Western Africa in the end of June. The Sahel area and southern Sudan depend on these rains because most part of their territory is desert.

The North American monsoon: It begins early in June and lasts till the end of September. It originates from Mexico and the Mexican gulf and in the mid July spreads over the southwestern US. The affected states from this phenomena are mainly Arizona, Utah , new Mexico, Nevada, Colorado, West Texas. However the coastal areas of the Southwestern US are rarely affected.

The South Asian Monsoon: These monsoons occur from June to September. It is divided in two branches-the Arabian Sea branch and the Bay of Bengal branch. The Arabian Sea branch brings rain to the west coast of India and then travels north. The Monsoon winds are vital to the agriculture of India. Even a delay of few days can be catastrophic for the India’s economy.

Northeast monsoon: It forms around September when the air over the northern parts of India begins to cool. An area of high pressure forms in the Northern parts of India and the wind is formed blowing to the Indian Ocean. On its way it picks moisture from the Bay of Bengal and pours it over the India peninsula and Sri Lanka.

East Asian monsoon: It affects Indo-China, Philippines, China, Korea and Japan. It characterizes with wet summer monsoon and dry and cold winter monsoon.