The sky is overcast. Dark, heavy clouds, thunder and flashes of lightning, it's suddenly much cooler. Then you feel the raindrops on your skin and you are overjoyed, wanting to jump and dance with joy. Listening to the pitter patter of rain against the roof and window panes, we gleefully watch everything around us turn into pools; we get set to launch our small paper boats and watch their haphazard course. Yes, most of us are helplessly in love with this magical season that brings fresh life to the parched land and its thirsty inhabitants.
Do you know where the rain comes from after the scorching summer? It is caused by seasonally reversing winds called the Monsoon. Monsoon also stands for the annual weather cycle within the tropical and subtropical continents of Asia, Australia, Africa and the adjacent water bodies; and the resulting rain fall.
During summer a low pressure area develops over the South Asian land mass, as it gets heated up, mainly because of the differential heat capacity of the land and water. There are two monsoon seasons — South-West monsoon and the North-East monsoon. During the months of June to September, the winds blow from the South-West direction from the Indian Ocean towards the Indian sub-continent. They are split into two branches — the Arabian Sea and the Bay of Bengal — and bring rain to most parts of the country.
Later from October to November, the land mass cools down and the winds reverse their direction to the North-East. As these dry winds diagonally cross from the north east to the south west and reach the eastern coast, they are humidified. They bring rain to Tamil Nadu and some parts of Kerala. Parts of West Bengal, Orissa, Andhra Pradesh, Karnataka and North-East also receive some rainfall.
The amount of precipitation and regional distribution varies drastically. It is around 400 cm in Meghalaya while in Ladakh and Western Rajasthan it is 10cm. Mawsynram near Cherrapunji receives the highest rainfall. According to the Guinness Book of World Records in 1985, Mawsynram received record rainfall of 28,000 millimetres (1,100 in). In the Northern Plains when it moves from east to west, the rainfall decreases.
Over 80 per cent of the annual rainfall in India is received from June to September. Though it is unequally distributed and erratic, the average rainfall in the country is around 125 cm.
The unpredictable nature of the monsoon always baffles us. According to S. R. Ramanan, Director of the Regional Meteorological Centre, Chennai, which makes short-term weather forecasts, after studying factors like atmospheric pressure variations and surface charts they prepare a 3D weather pattern based on which these predictions are made.
Typically, the south-west monsoon sets in the islands of Andaman and Nicobar by around May 25. It strikes the Malabar coast of Kerala by June 1. It reaches Mumbai by June 9 and travels up and strikes the Capital by June 29. While the Arabian branch follows the north-east course towards the Himalayas, the Bay of Bengal Branch takes the Coromandel coast route from Kanyakumari to Orissa and then veers North West to the Indo-Gangetic plain. It covers almost the entire country by the first week of July. The monsoon slowly retreats from North India by the end of August, and leaves the southern region by the end of November.
This year the monsoon reached the Kerala coast by May 29.
So, it's time to take a splash in the newly formed puddles!
Nature's fury
Monsoons are an influential climatic factor and their timely arrival is vital for our sustenance; our agriculture and economy is dependent on it. Sometimes, the monsoon plays spoilsport and wreaks havoc. Droughts, flash floods, cyclones, landslides and thunderbolts during this season claim a lot of lives every year and displace many. The monsoon is highly erratic in nature, sometimes it rains so heavily that is causes floods, and there are times when the rains fail causing droughts. Many studies attribute the cause of recent variations in monsoon and other climatic patterns to the phenomenon of global warming.
Folklore
People living close to Nature pay attention to minor variations in natural patterns as they are aware of their tremendous impact on their life. People still rely on signs from Nature to understand the weather. Here are a few:
Watch out for the ants. If you see them busy moving in lines carrying their eggs, then take it that it might rain any time. They build their hills with steep sides before rain and even cover up the entrance to keep the water out.
When you see a lizard sealing its burrow it is sure to rain in the next 24 hours.
House sparrows bathe in dry oil and hens roll around in dust, before it rains.
If you spot toads in large numbers, you need no further proof.
Before a storm or rain, you cannot spot any butterfly or bee on the flowers. When they know rain is due, bees don't even leave their hives.
Earthworms come out from their holes when it is about to rain.
If you find cattle or horses stretching out their necks and sniffing the air, then count on it that rain is here.
Everybody knows that peacocks love the rain and when you hear their shrill call, be prepared for rain and storm.
The garden spiders abandon their cobwebs when rain is almost there.
(Source: Internet)
The word monsoon is derived from the Arabic word mausim which means season. Mausam (weather) had found its way into Hindi, Urdu and several other North Indian languages. The Portuguese monção and Dutch monsun are also similar.
