The major desert areas of the world all lie between __ and __ degrees north or south of the equator.
10 and 30
What are the two ways wind erosion ways in?
deflation and abrasion
Define deflation.
the lifting and removal of loose sand and dust particles from Earth's surface
Define abrasion.
the sandblasting action of wind-blown sand
Deflation commonly occurs in semiarid regions where the protective cover of grass and shrubs has been removed by the activity of humans and animals. The results are board shallow depressions called what?
deflation basins
Wind can move only move sand and dust-sized particles, so the deflation leaves concentrations of coarser material known as?
lag deposits or desert pavements
What two landforms do abrasion leave behind?
ventifacts and yardangs
Wind transports sand by ____ and ____.
saltation and surface creep
Dust storms form thanks to what type of cloud?
cumulonimbus cloud
Explain have a sand dune migrates.
A sand dune migrates as sand grains move up the slope of the dune and accumulate in a protected area on the downwind face. The dune slowly moves grain by grain. As the grains accumulate on the downwind slope, they produce a series of layers (cross-beds) inclined in a downward direction.
Name the five types of dunes.
transverse, barchan, longitudinal, star, and parabolic dunes
Which type of dune usually covers sand seas?
transverse dunes
Barchan dunes form where the supply of sand is _____ and winds of moderate velocity blow in _____ direction.
limited; constant
What type of dune forms with three or more wind directions?
star dunes
What type of dune are formed with a limited sand supply and two wind directions?