WIND

  A wind is a current of air that is moving across the earth's surface. The movement in air occurs due to the difference in the pressures of the air. Winds always blow from the area of high pressure to the area of low pressure. The more the difference in the pressure, the stronger the movement. Winds are named by the direction from which they blow. For example, the wind blowing from the west is called west wind and from the east, is east wind.

3.1 Works of Wind

a.     Erosion
b.     Transportation
c.      Deposition
Like the river and the glacier, the wind has three kinds of work. The wind is very active in hot and temperate deserts. When it is strong, it blows away lose particles from the ground surface. It also erodes the exposed surface of the earth with sharp pieces of rocks that it carries.
          Here are some of the features formed by the winds:

a. Yardangs

          Wind scour produces alternating parallel ridges and furrows. Furrows are scooped out in layers of soft rocks. Beds of hard rock stand out as ridges in between the furrows. Such landforms are called Yardangs.

b. Mushroom (Gara) Rock

          The most common landform produced by erosion is called the Mushroom rock. These features have a broad top and bottom with a narrow trunk which indicates the maximum level of abrasion by wind. Exposed rock surfaces have irregular cavities caused by removal of weathered particles by wind.

c. Barkhans

          Barkhans are also known as transverse sand dunes because they are deposited at right angles to the direction of winds. Barkhans are crescent-shaped dunes. The horns of the crescent extend in the direction of winds. The central portion of the crescent is broad and high while the two horns are narrow and low. The windward slope of the barkham has a gentle and convex slope.

d. Loess

          Loess is the name given to a wind blown deposit of dust found in humid regions along the margins of deserts. Dust particles are carried by winds in a suspended state and they settle down when there is rainfall. The fine grains of dust cling together and settle down as a thick sheet covering the entire land surface.