TOPIC:-TYPES OF PRECIPITATIONS
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TOPIC: - TYPES OF PRECIPITATIONS
Precipitation due to turbulent ascent
There are five types of precipitation.
(1) Convective precipitation
(2) Orographic precipitation
(3) Cyclonic precipitation
(4) Frontal precipitation
(5) Precipitation due to turbulent ascent
Convectional precipitation results from the heating of the earth's surface. The warm ground heats the air over it. As the air warms, the air molecules begin to move further apart. With increased distance between molecules, the molecules are less densely packed. Thus, the air becomes “lighter” and rises rapidly into the atmosphere. As the air rises, it cools. Water vapor in the air condenses into clouds and precipitation. This type of precipitation is common in the Prairies and Ontario. The formation of convective precipitatio
(3) Orographic precipitation
It is due to the lifting of warm moisture laden air masses due to topographic barriers (such as mountains). All the precipitation we have in the Himalayan region is because of the Orographic ascent of air masses, rich in moisture content because of their long travel over oceans. The moist air masses get lifted up to higher altitude due to the pressure of mountain barrier and consequently undergo cooling, condensation and precipitation. Such a precipitation is known as orographic precipitation. In mountains ranges the windward slopes have heavy precipitation and leeward slopes light rain fall.
Cyclonic or Frontal precipitation results when the leading edge of a warm, moist air mass (warm front) meets a cool and dry air mass (cold front). The molecules in the cold air are more tightly packed together (i.e., more dense), and thus, the cold air is heavier than the warm air. The warmer air mass is forced up over the cool air. As it rises, the warm air cools, the water vapors in the air condenses, and clouds and precipitation result. This precipitation is common in Atlantic Canada. This type of system is called Frontal Precipitation because the moisture tends to occur along the front of the air mass. A cyclonic storm is a large, low pressure system that forms when a warm air mass and a cold air mass collide. This collision often occurs under the polar-front jet stream which spreads cold, dry arctic air near warm, moist tropical air. The rotation of the earth causes the air to circulate in a counterclockwise direction around an area of low pressure. The figure illustrates the patterns of wind flow, surface pressure, fronts, and zones of precipitation associated with cyclonic precipitation in the Northern Hemisphere. Around the low pressure (L), winds blow counterclockwise and inwards.
(5) Frontal precipitation
A boarder region between two adjacent air masses having different characteristics such as temperature and humidity is called a front. When a flow of warm and moist air mass from the south meets cold air mass of polar region, the cold air being heavier, under run the warm air flow in the form of flat wedge forcing the warm air aloft. The lifted warm air mass cools down at high altitudes causing precipitation. A front may be warm front or cold front depending upon whether there is active or passive ascent of warm air masses over cold air mass.
(6)Precipitation due to turbulent ascent
Air mass is forced to rise...
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