Dust Storms and its Impact on Climate.

 

WHAT ARE DUST STORMS?

Dust storm can be explained as a phenomenon when strong winds carry dust over an extensive area. 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.

Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transported by saltation and suspension, a process that moves soil from one place and deposits it in another. 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.

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 up-drafts. 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, a result of nearly similar weather conditions, like intense heat.

REASON FOR DUST STORM IN INDIA.

Reason for this particular ‘severe dust storm and thunderstorm’ activity in India was due to very high temperatures in Rajasthan and presence of western disturbance that led to the atmosphere becoming unstable. Moreover, easterly winds from the Bay of Bengal were also increasing the moisture over the area. The combination of all these factors resulted in this severe dust storm and thundershower activity. Scientists say high temperatures, moisture and an agitated atmosphere make a perfect combination for storms of this type. 

In such situations, particles become loosely held due to drought or arid conditions along with varied wind causes. Gust fronts might be produced by the outflow of air cooled by recent rains from an intense thunderstorm. However, the wind gusts might also be produced by a dry cold front which is a cold front that moves into a dry air mass while producing no precipitation.

IMPACT OF DUST STORM

Airborne dust presents serious risks for human health. Particles larger than 10 μm can damage external organs – mostly causing skin and eye irritations, conjunctivitis and enhanced risk of ocular infection.

Surface dust deposits are a source of micro nutrients for both continental and maritime ecosystems which can cause algal bloom.

Indirect dust deposit impacts include filling irrigation canals, covering transportation routes and affecting river and stream water quality

Reductions in visibility due to airborne dust also have an impact on air and land transport. Such as take-off and landing of planes.

Dust can impact on the output of solar power plants, especially those that rely on direct solar radiation. Dust deposits on solar panels are a main concern of plants operators.

As the climate gets warmer the temperature gradient is going to become very steep. This steep increase in temperature gradient will lead to heat waves and sand storms.

In the context of climate change, we can say that in north India the temperature is increasing more compared to south India. Increase in temperature means an increase in heating which means there will be more heat wave days and more reasons for occurrence of dust storm and thunderstorms.

With the rise in global temperature the soil is going to become drier so, the amount of soil that wind can carry is also increasing. With both the intensity of the wind and dryness of the soil increasing, the intensity of dust storm is going to further increase in the future. 

Drought and wind also contribute to the emergence of dust storms along with poor farming and grazing practices which expose the dust and sand to the high-speed winds.

Increasing desertification. It also reduces crop yields by burying seedlings, causing loss of plant tissue, reducing photosynthetic activity and increasing soil erosion.

Poor management of the Earth’s dry lands, such as neglecting the fallow system, are increasing dust storms size and frequency from desert margins and changing both the local and global climate, and also impacting local economies.