What is a monsoon?
Wind systems which change their directions seasonally, and originate from the temperature difference of the land and the sea, in a way that in the warm season they blow towards the land, in the cold season towards the sea. The monsoon name is typically used for the winds of the Indian Sea.
How are monsoon winds formed?
The monsoon wind system is a closed circulation, because their is a opposite current of air in upper layers compared to the bottom layer.
The tropical monsoon
The primary reason of the formation of monsoons, is the different warming-up of the seas and the land on the Earth's surface, and that the thermal and geographical Equator do not coincide and the thermal one is not parallel with the latitude circles.
Above the continents, that warm up better, in the summer in the northern hemisphere it moves apart towards north, in the southern hemisphere moves apart towards south from the Equator.
Because of the amplitude of the thermal Equator the trade wind crosses the geographical Equator, where because of the rotation of the Earth they change their direction.
The south-east trade wind of the southern hemisphere in the summer of the northern hemisphere crosses the geographical Equator by following the thermal Equator, and continues its way as south-western monsoon. In the summer of the southern hemisphere the north-eastern trade wind of the northern hemisphere crosses the geographical Equator.
Monsoons in temperate zones
The monsoon wind systems of temperate zones are formed by the seasonally fluctuating and different warming-up and cooling-down of the land and the nearby ocean, and by the different air-pressure coming with this phenomena.
In the winter land cools down more than ocean, therefore in the centre of the continents anticyclones form. In the winter these anticyclones result in current of air blowing from the land towards the sea close to the surface.
In the summer the distribution of air-pressure is opposite, therefore in the centre of the continents, which warm up better, low-pressure anticyclonic areas form, which result in current of air blowing from the sea towards the centre of land close to the surface.
The victims of the monsoon