5.Which of the following statements about planetary wind is true?Immersive Reader (1 Point) The winds blowing in particular locations due to specific weather conditions. Winds that blow all the time in the same areas of the world. Winds which blow at a particular period of the day or season of the year. The winds blowing only in a particular locations due to specific pressure conditions.
Answers
LOCAL WINDS -
DEFINITION
The local winds are truly local. They occur over a much smaller land scale and are related to the topographical features of that particular place. They blow for a short period and are caused due to the particular shape of the land or nearness to a body of water that generates a specific movement of air.
The examples of local winds in India: Kalbaisakhi (West Bengal), Loo (North India).
PLANETARY WINDS -
DEFINITION
Planetary winds, prevailing winds or permanent winds are those which blow continuously in the same belt all through the year. They blow from high pressure belt to low pressure belts. There are three main types of planetary winds - the trade winds, the westerlies and the easterlies. These winds are named according to the direction from which they blow.
ANTI-TRADE OR WESTERLIES - DEFINITION
These are variable winds and not as constant in strength and direction as the trade winds. The westerly wind belt is characterised by frequent cyclones and anti-cyclones. They blow from the subtropical high pressures belt 30
0
north and south of the Equator to the sub polar low pressure belt. In the Northern Hemisphere, they blow from SW to NE. In the Southern Hemisphere, the direction is NW to SE.
CHARACTERISTICS OF POLAR WINDS - DEFINITION
They are more variable in their strength and direction, in the Northern Hemisphere than in the Southern Hemisphere weather disturbances than in the Southern Hemisphere. They blow from the Polar High Pressure belt (90
0
N and S of the Equator) to the sub Polar Low Pressure belt (60
0
N and S of the Equator).
DEFLECTION OF WIND -
DEFINITION
The rotation of the Earth causes a force known as the Coriolis Force due to which they deflect more than a slow wind. The change in the wind direction as a result of the coriolis force is stated in Ferrel's Law. This law states that any horizontally moving fluid or object would deflect to the right in the Northern Hemisphere and to its left in the Southern Hemisphere due to the Earth's rotation.
PERIODIC WINDS -
DEFINITION
These are the winds blowing at a much smaller scale in comparison to the planetary winds.
The planetary winds include:
(1) Land and Sea Breezes
(2) Monsoons.
SEASONAL WINDS -
DEFINITION
Seasonal winds blow in a particular season. These winds have a seasonal rhythm. The best example of this is Monsoon. This season of winds is experienced in southern and eastern Asia. The rapid heating of land due to the hot summer over most parts of India causes the hot air to rise. The winds in the surrounding seas and oceans are moisture laden; they blow in and bring torrential rainfall.
MOUNTAIN AND VALLEY BREEZES - DEFINITION
Mountain and valley breezes form through a process similar to sea and land breezes. During the day, the sun heats up valley air rapidly while mountain remains relatively cooler. Convection causes it to rise, causing a valley breeze. At night, the process is reversed.
The winds blowing only in a particular locations due to specific pressure conditions.
Planetary winds
Planetary winds blow from high-pressure regions to low-pressure regions. Trade winds, Westerlies and easterlies are examples of different trade winds.
Trade winds
These winds blow from northern to southern hemisphere between degrees in latitude.
Westerlies
These winds blow from northern to southern hemisphere between degrees in latitude.
Easterlies
These winds blow from northern to southern hemisphere between degrees in latitude.
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