NASA in a statement said that rainfall accumulations from August 13 to 20 showed two bands of heavy rain across India.
As the monsoon rainfall caused severe flooding in Kerala and parts of Karnataka this year, the National Aeronautics and Space Administration (NASA) has, in a video, provided an estimate of the intense rainfall that affected India from August 13 to 20, using satellite data.
NASA in a statement said that rainfall accumulations from August 13 to 20 showed two bands of heavy rain across India. “Accumulated IMERG (Integrated Multi-satellitE Retrievals for GPM) rainfall estimates for the 1-week period from August 13 to 20 showed two bands of heavy rain across India. The first band appeared much broader and extends across the northern part of the peninsula with weekly rainfall totals ranging from over 120 mm (5 inches) towards the western half of the peninsula to as much as 350 mm (14 inches) over parts of the eastern half towards the Bay of Bengal. This first band is associated with the general monsoon circulation,” it said.
“The second band appeared more concentrated and intense and is closely aligned with the southwest coast of India and the Western Ghats where onshore flow was enhanced by an area of low pressure embedded within the general monsoon. Weekly rainfall totals in this band are generally over 250 mm (10 inches) with embedded areas exceeding 400 mm (16 inches). The maximum estimated value from IMERG in this band was 469 mm (18.5 inches),” said NASA adding that the summer monsoon is, however, a regular feature this time of year in India, and it can bring heavy rains to the region. But, periodically areas of low pressure can form within the general monsoon trough and bring even more rain.
Watch Video below
NASA said another contributing factor to the heavy rains along the southwest coast of India is the Western Ghats. “Although the extreme Himalayan topography located to the north is much more well-known, another contributing factor to the heavy rains along the southwest coast of India is the Western Ghats. Though much smaller than the Himalayas, this mountain range runs parallel to the West Coast of India with many peaks over 2,000 meters (6,500 feet).”
“As a result, the Western Ghats are well positioned to enhance rainfall along the West Coast of India as they intercept the moisture-laden air being drawn in off the warm waters of the northern Indian Ocean and the Arabian Sea as part of the southwest monsoon circulation,” the space agency said.
IMERG is used to estimate precipitation from a combination of passive microwave sensors, including GPM’s GMI microwave sensor and geostationary IR (infrared) data. GPM is the Global Precipitation Measurement mission core satellite. GPM is a joint mission between NASA and the Japan Aerospace Agency, JAXA.
Kerala is facing its worst floods in nearly a century that has left at least 231 people dead, and forced 3.14 lakh people out of their homes. The Centre has declared this calamity of ‘severe nature’.