eastern region oil spill disaster contingency plan - Indian Coast Guard

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51. North East Monsoon Season. The period from October to
December is termed as the ‘Post Monsoon Season". It is also known as the '
North East Monsoon Season". There are no well established criteria for declaring
the outset of NE Monsoon. However a sudden increase in rainfall activity along
Andhra and Tamil Nadu coast by about middle of October and reversal of surface
wind form SWly to NNEly are generally considered as the general criteria of
setting of the NE Monsoon. During the first week of September the South West
Monsoon starts withdrawing from the extreme northern and north - western
parts of the country, between second half of September and first half of October
it withdraws from the entries northern, North-Western most parts of central and
Northern parts of peninsular India. When the Southwesterly winds retreat
southwards down the Bay of Bengal, they are replaced by winds from the
Northeasterly and while withdrawing the Monsoon gives considerable rainfall to
the South Peninsula and for this reason the period from October to December is
also known as the retreating Monsoon Season.
52. During this season Mean Sea Level Pressure, Surface Air temperature and
Upper wind circulation patterns over the Indian Sub continent and the Indian
seas undergo rapid changes from the summer type to the winter type. The
month of October is considered as the transitional period between Monsoons.
This month is also considered as the representative month of this reason. During
this period, the seasonal Low pressure is of South West Monsoon Season over
North West India becomes unimportant. A shallow Low pressure Area appears
over west Central and adjoining South West oriented trough line through this
seasonal Low pressure area from Bay of Bengal to the Arabian Sea across the
land areas in noticed. The seasonal Low-pressure area and the associated trough
line shifts southerly as the NE Monsoon Season progresses. Most of the Low
Pressure Areas/ Depressions develop in Bay of Bengal over the East-West
oriented trough.
53. Rain fall and Surface winds. During this season the south
peninsular India Comprising the Meteorological sub divisions of coastal Andhra
Pradesh, Rayalaseema, Tamil Nadu and Kerala experiences significant rainfall.
The southern peninsula particularly the Meteorological subdivisions along the
East Coast namely Coastal Andhra Pradesh and Tamil Nadu get considerable
amounts of rainfall of the year during this season. For the state of Tamil Nadu
this is the main rainfall season. This rainfall in the beginning of the season