Why satellites are missing crucial farm fires in Punjab and Haryana, and how that’s about to change

The NRSC, Indian Council of Agricultural Research (ICAR)-IARI and remote sensing centres of Punjab and Haryana are carrying out an in-season pilot to firm up the methodology this Kharif season. The agencies are using European Sentinel-2 satellite for this, which has a 20-metre resolution and passes every fifth day. They provide optical images, near-infrared images and short-wave infrared 1 and short-wave infrared 2 images, helping in mapping burn scars on fields.

The agencies involved had been mapping burnt areas earlier too, albeit independently.

CAQM initiated a discussion on gaps in farm fires count in January. It formed a committee under NRSC to standardise a protocol for mapping areas burnt by paddy stubble fire.

“Thermal imaging satellites, even with a finer resolution, cannot track each and every fire incident. They will capture those fire events that are occurring as they (satellites) are passing over, so there is always an undercounting bias,” said a scientist.

ICAR-IARI, NRSC and the state remote sensing centres use data collected by Suomi NPP, Terra MODIS and Aqua MODIS satellites. The in-season pilot has been checking real-time what are the impediments faced while mapping burnt areas. For instance, smog can lead to poorer detection and solutions are being tested. On the issue of undercounting, the scientist said, “We are aware of this issue and hence we have been working together to fine-tune fire detection.”

On Monday, it was pointed out to the Supreme Court that there could be an undercount in the data on farm fires collected through the polar-orbiting NASA satellite. Farm fire events in Punjab have dropped from 82,147 in 2020 to 10,104 till November 20 this year; in Haryana the count has dropped from 6,464 to 1,183 in the same period, according to data from IARI.

Relying on X posts of a NASA scientist, Hiren Jethva, it was pointed to the apex court that data from the geostationary GEO-KOMPSAT 2A, a Korean satellite, had picked up fires after NASA’s polar-orbiting had passed over, raising questions over the count of farm fires. The Supreme Court then directed the CAQM to obtain data from the Korean satellite or any other satellite to enable action at the state level.

On geostationary satellites, a scientist said, “The available geostationary thermal sensors are not suitable for farm fire detection as the sensors have coarse resolution and have low sensitivity to small fires.”