Digital elevations from ICESat: Effects of dynamic terrain

Substantial problems arise from the sand movement in civilian and industrial cities in arid and semiarid countries. Problems are caused by the encroachment of sand on roads and railway tracks, farm-lands, towns and villages, industrial installations, airports, etc. Sand movement is highly affected by geomorphology such as vegetation, shapes and heights of terrains, and grain sizes of the sand [1]. However, wind direction and speed are the most important factors that affect sand movement. A minimum wind speed of 6 – 8 m/s is needed for sand to transport. With increasing wind speed there is an exponential increase in potential sand movement [2]. One of the most active areas regarding sand and dunes movement is the area of Arabian Peninsula. Approximately one-third of the Arabian Peninsula is covered by sand dune areas (Fig. 1). Different wind regimes that cause sand dune movements occur in the deserts of the Arabian Peninsula. Winds capable of moving sand have a northerly component 75 percent of the time and a southerly component 17.4 percent of the time; the remainder is from the east or the west [3]. The frequency of northerly winds is highest in April, May, and June and lowest in February and March. The frequency of southerly winds is relatively high in February and March but extremely low during May and June [3]. Thus, the amount of sand blown from north to south is highest in spring and summer and lowest in winter. In contrast, the amount of sand blown from south to north is highest in winter and lowest in spring and summer.