Question

What are the regional and seasonal variations of monsoon in india

Answer 1

The Indian Monsoon Current refers to the seasonally varying ocean current regime found in the tropical regions of the northern Indian Ocean. During winter, the flow of the upper ocean is directed westwayesrd from near the Indonesian Archipelago to the Arabian Sea. During the summer, the direction reverses, with eastward flow extending from Somalia into the Bay of Bengal. These variations are due to changes in the wind stress associated with the Indian monsoon. The seasonally reversing open ocean currents that pass south of India are referred to as the Winter Monsoon Current and the Summer Monsoon Current (alternately, the Northeast Monsoon Current and the Southwest Monsoon Current).The Somali Current, which is strongly linked to the Indian monsoon, is also discussed in this article.
Although Mariners have been aware of the existence of the Monsoon current for nearly one thousand years, a detailed understanding did not emerge until after the International Indian Ocean Expedition of the 1960s. The World Ocean Circulation Experiment of the mid 1990s permitted detailed measurement of these currents through an extensive field campaignIn the northern hemisphere tropical regions of the Atlantic and Pacific oceans, surface winds blow predominantly from the northeast year round, with westward-flowing ocean currents underneath. The Indian Ocean differs from the Atlantic and Pacific in that a continental landmass forms a complete northern boundary at relatively low latitudes. Monsoonal circulations are driven by the differences in temperature between land masses and adjacent oceans.Because water has a larger thermal capacity than air, land surfaces will heat more rapidly during the summer season. The Indian monsoon consists of two phases. During the northern hemisphere winter, the cool Asian landmass contains a broad area of high pressure, whereas lower pressures prevail over the warmer Indian Ocean and hot Australian continent. This pressure pattern helps to reinforce the northeasterly trade winds. During the northern hemisphere summer, the Asian landmass (especially the Indian subcontinent) heats considerably, generating an area of low pressure to the north. Circulation about this low generates strong winds from the southwest over the Arabian Sea and along the Somali coast. These winds are enhanced by the formation of an atmospheric western boundary current created by the high terrain over eastern Africa.

A consequence of the Coriolis effect, Ekman theory explains that oceanic flow at the surface is directed at 45 degrees to the right of the wind stress in the Northern Hemisphere. Thus, winds blowing from the southwest result in eastward currents, while winds blowing from the northeast result in westward currents.