deserts

Question 1

explain the role of wind in hot deserts

Answer 1

abrasion - sand papering effect from small particles smashing against rocks . this is down to the prevailing wind direction, wind speed and other factors
deflation - when lose sediment is swept away from the wind leaving behind a desert pavement
suspension - small particles carried in the wind , usually less than 0.2mm in size
saltation - sand sized particles hop along the surface, can be transported in air but only for a short distance

Question 2

explain different forms of weathering

Answer 2

thermal fracture - due to large diurnal range rocks experience rapid contraction and expansion causing them to crack under the increased pressure
exfoliation - is the onion peeling effect due to temperature and pressure changes.
oxidation - the breakdown of rocks due to the reaction with oxygen and water shown by a deep brown colour
hydrolysis - mild acids react with the rocks to create dissolvable rocks

Question 3

desertifcation key facts

Answer 3

since 1950 ethiopias population has increased by 300%
putting increased pressure on land
since 1940 650,000 km2 of the sahel region has turned into desert
the desertification of the gobi desert causes an annual GDP loss of 23.14%
in the 1970s severe droughts in the sahel region caused 250,000 deaths and 3.5 million cattle deaths