FARM FIRES

• The Indian Agricultural Research Institute’s (IARI) Consortium for Research on Agroecosystem Monitoring and Modeling from Space (CREAMS) Laboratory collects data on paddy residue fires.
• The laboratory puts out a daily bulletin on paddy residue fires, carrying data from Punjab, Haryana, Uttar Pradesh, Rajasthan, Madhya Pradesh, and Delhi.
• The bulletin provides a district-wise breakdown of the number of farm fire incidents recorded, as well as comparative figures from previous years (2020 onwards).
• It also gives the exact location where these fires were recorded, the satellite that recorded them, the time of recording, and their intensity or firepower.
• The CREAMS Laboratory was set up in 2013 to monitor crop conditions against extreme climatic events.
• In 2018, the Union government started the central sector scheme on crop residue management and asked the laboratory to monitor farm fires to determine the impact of the scheme.
• The data is collected by three sensors aboard three different NASA satellites: one called VIIRS aboard the Suomi NPP satellite, and two called MODIS, aboard the Terra and Aqua satellites.
• These sensors record land surface temperatures. Each satellite passes over the Indian subcontinent twice every 24 hours, at different times.
• The VIIRS has the highest resolution, so it captures more events than the two MODIS satellites.
• For the past five years, the laboratory has also been using Sentinel-2 satellites, belonging to the European Space Agency, to map the burnt areas.
• This mapping is not done in real-time but towards the end of the season. It tells us, in hectares, how much was planted, how much was burnt, and where.

• IARI receives satellite data from its own ground station and the National Remote Sensing Centre. Farm fires are monitored throughout the country all year round.
• Before 2021, there was no standard protocol for monitoring farm fires. However, in 2021, the Commission for Air Quality Management (CAQM) established a standard protocol. IARI reprocessed data for 2020 using the new protocol, enabling comparative data from 2020 onwards.
• The Punjab Remote Sensing Centre also puts out the same data on farm fires in Punjab.
• Researchers differentiate paddy crop residue fires from forest fires or industrial fires by first identifying areas under paddy cultivation and then mapping farm fires accordingly.
• Paddy has a distinct reflectance signature, enabling researchers to distinguish it from other crops.
• Satellites provide land surface temperature data. If the land surface temperature exceeds a certain threshold compared to its surroundings, it indicates a fire.
• The threshold varies with season, day, and night. Fire locations are determined and aggregated by state, district, and tehsil. Satellite data is used to determine the time of detection.

5. What happens once the bulletin is prepared?

• The bulletin is sent out to central and state-level agencies, including the CAQM, the Ministry of Agriculture, and state agriculture departments in Punjab, Haryana, UP, Rajasthan and Madhya Pradesh.
• The location data helps identify burning “hotspots” or districts where focused measures are needed, such as ensuring the availability of machinery.
• Punjab and Haryana have also set targets for a reduction in farm fire numbers this year based on satellite data on farm fires in different districts.

5.1. The limitations of the data

• The first limitation is about the number of satellites in operation. With more satellites, you can get passes every hour, or every half hour. The higher the number of these passes, the more events we can capture.
• Then there are climatic conditions that can influence readings. The sensors aboard the satellites work somewhat like an infrared thermometer but from a distance of 600 to 800 km.
• Between them and the fires they want to catch lies Earth’s atmosphere. Some absorption of the signal happens because of the presence of water vapour and clouds. If we have thick, persistent clouds, we don’t get data. The sensors can only see the top of the cloud and the cloud top temperature is minus 50 degrees.
• Earlier this month, there was a delay in receiving data from one of the satellites. Sometimes, the sensor needs to be recalibrated. In this case, there was a change in the orbit of the satellite.