Question

describe the mechanism of monsoon ?and

give an account of weather conditions and characterstics of cold, hot , rainy, and reatreating monsoon seasons ?

Answer 1

Monsoon is a tropical phenomenon.During the hot sub-tropical summers,the massive landmass of Indian Peninsula heats up resulting in pressure gradient from North to South.This causes flow of moisture laden winds from North to South,causing rainfall in most parts of the sub-continent.This is termed as South west monsoon.Reverse happens during winter when the landmass is colder than sea establishing a pressure gradient from land to sea.The winds start blowing from Indian landmass to Indian Ocean in a northeast direction.This is the northeast monsoon.Southeast monsoon carries more moisture and heavy rainfall occurs whereas northeast monsoon carries less moisture causing low rainfall.

1.During cold weather season,i.e from mid-November to the end of February in Northern India temperature decreases from south to north.A important characteristic of the cold weather season in the northern plains is the inflow of cyclonic disturbances from west and the northeast.They cause the much needed winter rains and snowfall in the mountains.
2.Hot summer season starts from mid March and ends in mid-September.April and May are the hottest months of the summer season.Loo is the striking feature of the hot weather season.They are the strong,dusty,hot winds blowing during the day.Towards the close of the summer season,pre-monsoon showers arrive causing rainfall in Kerala and Karnataka.
3.The inflow of the south west monsoon into India brings about a total change in weather.The windward side of the Western Ghats receives heav rainfall whereas the Deccan Plateau and the parts of Madhya Pradesh also receives rainfall in less amount inspite of lying in the rain shadow area.The highest rainfall is received in the north-eastern part of the country.
4.During October to November,with the apparent movement of the sun towards the south,the monsoon trough over the norther plains become weaker.A high pressure system takes place.The south-west monsoon gets weaker and starts retreating from the northern plains.This is the retreating monsoon characteristic.