ABSTRACT
A dust storm is a meteorological phenomenon common in arid and semiarid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Particles are transported by saltation and suspension, a process that moves soil from one place and deposits it in another. Drylands around North Africa and the Arabian Peninsula are the main terrestrial sources of airborne dust, in addition to some contributions from Iran, Pakistan, and India into the Arabian Sea, and China’s significant storms deposit dust in the Pacific. It has been argued that, recently, poor management of the Earth’s drylands, such as neglecting the fallow system, is increasing dust storms’ size and frequency from desert margins and changing both the local and the global climate, besides impacting local economies. In desert areas, dust and sand storms are most commonly 700caused by either thunderstorm outflows or strong pressure gradients, which cause an increase in wind velocity over a wide area. 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 ft (6,100 m). 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.
