Astro Meterology II

After three days of dark clouds, lightning and rainfall, Kerala is back to normal.

Rains are expected to accelerate after Edava Pathi, which starts on May 29, when the Sun transits the 15th degree of Sidereal Taurus.

Jupiter in watery Pisces, Mars in Leo and Venus in Gemini should bring rains to Kerala.

Monsoons have been defined as sea breezes or wind systems. A wind system which reverses direction seasonally, blowing from the southwest for six months and from northeast for six months. Its extreme examples are in South Asia and Africa. Winds which influence climatic seasons, with concomitant rainfalls !

Annual temperature trends over sea and land are the causes of the monsoons. Monsoons normally blow from cold regions towards warmer regions. They blow from the sea towards land during summer and from land towards sea during winter.

Of all monsoons, the South West Monsoon is the largest. This Asian monsoon is the atmospheric response to the shift of the overhead Sun, from the Tropic of Capricorn in December to the Tropic of Cancer in June.

India lies exactly on the Tropic of Cancer, the apparent position of the Sun at the summer solstice. It is 23 degrees and 27 minutes ( which is the maximum declination of the Sun ) north of the Equator. India also lies on the equator. Pakistan lies north and is more drier than India. Pak does not get these monsoons.

Edava Pathi, the South West Monsoon

In June, Sun is almost at the Tropic of Cancer and northen part of the Indian subcontinent becomes very hot. During summer, the northern and central side of India and the Thar desert heat up considerably, causing a low pressure area over central and northern Indian subcontinent. The Indian Ocean sends moisture laden winds, to fill this void. These moisture rich winds move towards mighty Himalayas, creating wind blowing storm clouds towards the subcontinent. Himalayas block these winds from entering Central Asia, thus propelling them to rise. The clouds gain immense altitude, temperature drops sharply and thus precipitation occurs !

Thula Varsham, the North East Monsoon

In Dec, Sun is almost at the Tropic of Capricorn ( 23 degrees 27 minutes south of the Equator ) and the Indian Ocean becomes hot and the northern land mass of India becomes cool. Hence winds rush from the cold North to the South . The cold winds blow from the northen subcontinent, sweeping down on the Himalayas and the Indo- Gangetic plains, towards the comparitively hot Indian Ocean. This is known as the North East Monsoon or rather the Retreating Monsoon and this causes Thula Varsham, the rains caused by the Sun’s ingress into sidereal Libra. These cold winds from the North pick up some moisture from the Bay of Bengal and rains hit Sri Lanka & India. Madras receives rains and 60% of the rains received by Tamil Nadu is from this monsoon.

The eastern parts of the Western Ghats do not get the SW Monsoon and hence places like Madras do not get its blessings. Madras gets the North East Monsoon in Oct-Nov, after Karkyadi ( when the Sun enters the first degree of Cancer ), when the Sun retreats South ( Dakshinayana ), when the northern side of the Indian subcontinent becomes cool and the cool winds precipitate the North East Monsoon.

Physiologists like Dr Walter Cannon ( The Wisdom of the Body ) talked about self regulating mechanisms or homeostatic control systems in the body physiologic. Arent these monsoons the homeostatic or self regulating control systems of Divine Nature ?

One is reminded of a verse from Longfellow

Nothing that is shall perish utterly
But shall revive again
As clouds restore through rain
The exhalations of the land and the sea !