A History of Agriculture in India v1.c9.s1.2

v1.c9.s1.2

With the advance of summer, associated with the ‘northing’ of the sun, insolation increases rapidly over the higher latitudes so that by the end of May the region of the highest air temperature and the lowest atmospheric pressure lies over north-western India and the adjoining areas of Pakistan, Afghanistan, Iran and Central Asia. This low-pressure system takes over control, as it were, of the air currents over Asia, so that the south-east trade winds from the south of the equator, after being diverted into the Arabian Sea and the Bay of Bengal, appear suddenly over the west coasts of India and Burma, respectively, as the south-west monsoon. The Arabian Sea branch of the south-west monsoon, while crossing the Western Ghats, gives copious precipitation over that region, and continues to drift eastwards across the Deccan and the central parts of the country, meeting the bay branch of the monsoon along the trough of low pressure which extends from Orissa to north-western India. The bay branch is deflected by the Arakkan Yomas and turned in its course so as to skirt the northern side of the low-pressure trough while moving along the submontane tracts to the south of the great Himalayan barrier.