Distribution of wind activity
Approximately 10% of the earth's land surface may be described as hot desert. In this area the action of wind plays a vital part in landscape development. The wind carries abrasive fragments of rock and redistributes the material to leave vast expanses of land bare while covering others with layers and folds of sand. Wind activity is also important in the polar deserts (another 10% of the earth's landscape), where it also shapes the land. The polar winds remove sediment from river plains and carries it many kilometres across the land's surface. In the past, polar winds carried and left behind deposits known as loess. These occur in the temperate lattitudes that were much colder because polar ice sheets once extended into these areas. More later... |