Sand and dust storms are common meteorological hazards in arid and semi-arid regions. They are usually caused by thunderstorms — or strong pressure gradients associated with cyclones — which increase wind speed over a wide area. These strong winds lift large amounts of sand and dust from bare, dry soils into the atmosphere, transporting them hundreds to thousands of kilometres away. Comparatively, Australia, America and South Africa make minor, but still important, contributions.
Global estimates of dust emissions, mainly derived from simulation models, vary between one and three Gigatons per year. Once released from the surface, dust particles are raised to higher levels of the troposphere by turbulent mixing and convective updrafts.
They can then be transported by winds for lengths of time, depending on their size and meteorological conditions, before being pulled back down to the surface again. As larger particles sediment more quickly than smaller ones, there is a shift toward smaller particle sizes during transport. Dust is also washed out of the atmosphere by precipitation. Aerosols, particularly mineral dusts, impact weather as well as global and regional climate. Dust particles, especially if coated by pollution, act as condensation nuclei for warm cloud formation and as efficient ice nuclei agents for cold cloud generation.
The ability of dust particles to serve as such depends on their size, shape and composition, which in turn depend on the nature of parent soils, emissions and transport processes.
Dust particles also influence the growth of cloud droplets and ice crystals, thus affecting the amount and location of precipitation. Again, the ability of dust particles to absorb solar radiation depends on their size, shape and mineralogical and chemical composition. The vertical distribution of dust in the air vertical profile and the characteristics of the underlying surface are also required to quantify this impact.
Airborne dust presents serious risks for human health. Pretty early on, it seems. We are resisting the urge to philosophize and will instead ask you what did you think of this Wonder about sandstorms? We are undergoing some spring clearing site maintenance and need to temporarily disable the commenting feature.
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Join the Discussion. Paige Mar 16, Can you tell me where sandstorms occur most often? Apr 5, Jessana Mar 31, Mar 31, That sounds pretty extreme, Mr. So Lit Apr 8, Mar 29, Aquaman Mar 27, Aquaman Apr 3, Apr 4, We may have heard about sandstorms at one point in our lives. While it is common knowledge that it comprises of sand and that it could cause several adverse effects towards the environment and the well-being of the people, there are still a lot of things that we do not know about the phenomenon.
On this article, we are going to describe a sandstorm and its causes and effects, including several interesting facts about it. A sandstorm is described as a natural phenomenon that occurs when a strong wind, such as a gust front, blows fine sand particles and dust from a dry surface.
These particles become suspended in the air, causing erosion where they initially were. The wind drops these particles in another place where silt is formed. Also known as a dust storm, a sandstorm is common in arid and semi-arid regions.
The primary terrestrial sources of airborne dust include the drylands around the Arabian Peninsula and North Africa. A sandstorm is usually confined to the lowest ten feet. It rarely rises to more than fifty feet above the ground. The sand particles which are picked up by the sandstorm are larger than dust particles. They usually fall out of the storm more rapidly, causing it to launch not far from where the sand was initially at.
It is thought that the particles also fall to the ocean, significantly affecting the marine ecosystem. It is worth noting that the frequency of sandstorms has been increasing, albeit a well-known meteorological phenomenon since the ancient times.
It has raised several health and environmental concerns due to the gravity of its surge. As mentioned earlier, a sandstorm is caused by strong winds that blow over loose sand particles. The force of the wind makes the sand particles vibrate. The particulates are then eventually carried up before being brought down to the ground again. This process is called saltation. As saltation is repeatedly done, these particles break into smaller particles. Once they have become fine particles, they begin to travel through suspension.
The strong winds that blow these particulates off the ground are usually formed by the outflow of rain-cooled air which was produced by a severe thunderstorm.
A dry cold front could also produce sandstorms. Dry cold fronts are cold fronts that do not produce precipitation because they move into a dry air mass. In deserts, sandstorms are commonly caused by the outflows of a thunderstorm , or by a strong pressure gradient. At several times of the year, sandstorms become more prevalent in desert regions because the intense heat mixed with the air makes the lower atmosphere more unstable.
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