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Depression2 a region of low atmospheric
pressure. A depression forms as warm, moist air from the tropics mixes
with cold, dry polar air, producing warm and cold boundaries and unstable
weather low cloud and drizzle, showers or fierce storms. The warm air
being less dense, rises above the cold air to produce the area of low
pressure on the ground. Air spirals towards the centre of depression in
an anticlockwise direction in the northern hemisphere, clockwise in the
southern hemisphere. Depression occasionally develops in the deep-sea
area of the indian
ocean or in the bay
of bengal. The timing of such depressions coincides with the
southwest monsoon
wind. During such depressions, continuous heavy rainfall occurs in Bangladesh
and adjoining areas for 7 to 10 days. At times more than two to three
weeks of rainfall may occur in sylhet
and cox's
bazar areas. [Mohd Shamsul Alam] |
