Dust Blowing Off Coast of Oman22.4N 58.0E
Some dust can be seen blowing off the coast of the Arabian Peninsula on the right side of this image. The dust seems to blow over Oman and then out over the Arabian Sea and northward over the Gulf of Oman towards Iran. Drought and wind contribute to the emergence of dust storms, as do poor farming and grazing practices by exposing the dust and sand to the wind.
As the force of wind passing over loosely held particles increases, particles of sand first start to vibrate, then to saltate (“leap”). As they repeatedly strike the ground, they loosen and break off smaller particles of dust which then begin to travel in suspension. At wind speeds above that which causes the smallest to suspend, there will be a population of dust grains moving by a range of mechanisms: suspension, saltation and creep.
The vertical extent of the dust or sand that is raised is largely determined by the stability of the atmosphere above the ground as well as by the weight of the particulates. In some cases, dust and sand may be confined to a relatively shallow layer by a low-lying temperature inversion. In other instances, dust (but not sand) may be lifted as high as 20,000 feet (6,100 m) high.