- March 16, 2021
- Posted by: OptimizeIAS Team
- Category: DPN Topics
Context : Beijing witnesses biggest dust storm in decade.
- 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.
- Sand and dust particles are distinguished by their grain size. Storms carrying bigger particles are known as Sand Storm whereas those carrying smaller are called dust Storms.
- Marginal dry lands are increasingly a source of major dust storms. These areas have fragile, delicately balanced ecosystems. Their degradation, called desertification, makes the soil less resilient to wind during prolonged drought.
Formation of Dust Storms
- Sand and dust storms usually occur when strong winds lift large amounts of sand and dust from bare, dry soils into the atmosphere.
- Once released from the surface, dust particles are raised to higher levels of the troposphere by turbulent mixing and convective updrafts.
- They are 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.
- Areas which have higher moisture witness thunderstorm and areas relatively devoid of moisture suffer from dust storms.