The National Aeronautics and Space Administration (NASA) has released a video created using satellite data that provide an estimate of the intense rainfall over India in the past week and show the spread of the resulting severe flooding in Kerala and parts of Karnataka.
Rainfall accumulations from August 13 to 20 show two bands of heavy rain across India, NASA said in a statement on Wednesday.
The first band appears much broader and extends across the northern part of the peninsula with weekly rainfall totals ranging from over 5 inches towards the western half of the peninsula to as much as 14 inches over parts of the eastern half towards the Bay of Bengal. The first band is associated with the general monsoon circulation.
The second band appears 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 10 inches with embedded areas exceeding 16 inches. The maximum estimated value from the data in this band is 18.5 inches, NASA said.
Another contributing factor to the heavy rain along the southwest coast of India is the Western Ghats. The Western Ghats, with many peaks over 2,000 metres, 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 Arabian Sea as part of the southwest monsoon circulation.
The Integrated Multi-satellite Retrievals for GPM is used to estimate precipitation from a combination of passive microwave sensors, including microwave sensor and infrared data. The data are generated every half an hour, thereby allowing scientists to track rainfall across the globe almost in real time. GPM is the Global Precipitation Measurement mission core satellite. GPM is a joint mission between NASA and the Japan Aerospace Agency, JAXA.