The sand dunes are formed by wind deposition of fine particles. The shapes of sand dunes can easily be changed by the changing wind direction and intensity due to the loose nature of the sand particles. Sand dunes occur not only in the arid areas, but also in coastal environments. The sand dunes are very dominant features in the desert environments.
There are various types of sand dunes, including barchans, seif dunes and transverse dunes. These are a result of different wind speed, direction and depend on the nature of available sands. Indeed, wind plays an important geomorphological role in arid areas because of the absence of vegetation to protect the surface and the lack of moisture to bind the particales together.
The sand dunes can change with change in rainfall patterns and regimes.
Look at the flash below and explain sand dunes can be affected by changing climate.