(i)Explain the process of wind erosion.
(ii)With the aid of a diagram, describe the feature of a barchan dune.

This was a very popular question among the candidates and most of the candidates that answered the question performed well.  Those who performed well were able to explain the processes of wind erosion like abrasion, deflation and attrition.  They were also able to describe the features of a barchan dune and could illustrate these features with diagrams.  The few candidates who performed poorly were those who could not describe the features of barchan dunes.  The features of barchan dunes include:
-           crescent or half-moon shaped
-           occurs individually or in groups
-           has two horns which always point in the direction of the prevailing wind
-           has steep and concave slope at the leeward side
-           migrates at an annual rate of 8-16 metres
-           grows up to 30 metres high and 360 metres wide
-           lie transversely to the wind direction
-           several barchans may coalesce into a line of irregular ridges.