A satellite-based alert on a forest fire did not go out to officials of the Forest department in Tamil Nadu on Sunday when a blaze trapped trekkers in Theni, Siddhanta Das, Director-General Forests, told The Hindu on Tuesday.
The Forest Survey of India, since 2004, has in place a system to monitor fires real-time. It then informs State departments about active forest fires. It does so based on satellite inputs from ISRO’s National Remote Sensing Centre (NRSC). “Typically, the FSI, based on satellite mappings, alerts all forest departments. For some reasons, this fire-alert didn’t go out to the State forest department. I am not sure of the precise details as I was not in Delhi when this happened,” he said. Multiple sensors aboard the NASA satellites – Terra and Aqua – pick up thermal images of forest fires if they are under way in India and relay it to the State forest departments at prescribed times – 1:45 p.m. and 10:30 a.m. – via SMS .
‘Human-made fire’
Another set of alerts are generated by a different group of sensors, called VIIRS, aboard the Suomi NPP spacecraft. From here, alerts are issued around midnight, 2 a.m. and 1.30 in the afternoon. While the sensors on these satellites are tuned to a higher resolution, they are still in “experimental mode” as per the NRSC database.
“It’s possible that the satellite passes didn’t coincide with the time the fires actually began and so fire alerts didn’t go out. In this case, however, the fire was human-made, as is the case with 90% of forest fires across India,” Mr. Das added.
While the current system of detecting active fires via satellite images has been in place since 2004, the forest department, since 2016, has been working on a system of generating “pre-warnings.” Such alerts of a fire threat are given a week in advance based on forest cover, type of forest, climate variables and the past fire-activity in the area. “This system has not been put into operational use yet,” Mr. Das added.
According to India’s State of Forest Report 2017, fire alerts issued to Tamil Nadu went up from 89 in 2013 to 301 in 2017.
