Study: Dust storms over N Indian plains getting less intense
FINDINGS Iitbhubaneshwarled study says skies are getting clearer
MUMBAI: A decline in dust emissions from the Great Indian Desert — Thar — and weakening winds have led to a decrease in the intensity of dust storms over northern India in the summer and clearer skies across the IndoGangetic Plains, says a study led by the Indian Institute of Technology – Bhubaneswar (IITBBS), Odisha.
The team, analysing data from multiple ground and satellitebased measurements, found a 15% to 20% reduction of dust particles in the atmosphere during the pre-monsoon season — March to May — between 2000 and 2016 over multiple locations in the IGP. A decrease in dust was measured in the atmosphere below 2 to 2.5km altitude.
The study is i mportant because dust particles affect weather and hence climate through their effect on how much solar radiation reaches the ground or gets reflected back to the space. They also modify the way clouds form .
“We found that increased rainfall during the pre-monsoon season over the north-western part of the Indian subcontinent, including Pakistan and parts of India, is leading to wet soil, which is reducing wind erosion, thereby resulting in reduced dust emission,” V Vinoj, lead author and assistant professor, School of Earth, Ocean, and Climate Sciences, IITBBS told HT. “The increased rainfall also removes any suspended particulates in the atmosphere, and cleaner air.”
The study also found that a decrease in dust particulates — the largest constituents in the air during the pre-monsoon season over the sub-continent— translated into clearer skies over the Indo-gangetic Plains (IGP) with the scattering and absorption of light at the earth’s surface also getting low at 3% per year during the same period.
“Local dust is also declining over the Indian region. This can alter the early monsoon rainfall we depend on,” said V Vinoj, lead author and assistant professor, School of Earth, Ocean, and Climate Sciences, IITBBS .
A previous study by Indian Institute of Technology–bhubaneshwar (IITBBS), had shown how dust from West Asia, combined with local factors, influences the therefore summer monsoon rainfall that India is heavily dependent upon.
The study showed that when dust absorbs solar radiation over the Arabian Sea, it warms the area and strengthens winds carrying moisture eastward. This leads to India receiving more rain a week later. According to the new study, the reduction in extinction — or cleaner sky — was spread from Lahore in Pakistan to Kanpur in the east.
With these new findings, researchers said it is yet to be studied whether the increase in pre-monsoon showers, decrease in dust emissions, and weakened winds will affect total rainfall
Researchers said clear skies, owing to a decrease in dust emissions, was strong over the arid and desert regions over northwestern part of Indian subcontinent, including the Thar Desert.