This year’s Amazon fire season is one of the most serious ever, even though it’s not attracting near the media attention as last year. More than one thousand major fires have already been detected in the rainforest biome this year, with 82 major fires reported in protected areas and Indigenous territories, as of September 10, 2020.
Across the Brazilian Amazon, September has averaged 53 major fires per day (up from 18 in August) says the non-profit MAAP. But according to other sources, there are more than 6,000 hotspots flaring up in just a single day.
With statistics like these apparently diverging so widely among multiple sources, how do we know for sure what, and how much, rainforest is truly burning where? And how exactly are all these fires detected, and what do these numbers mean in reality?
To answer, we have to start in space.
Many satellites circle the Earth daily, some outfitted with tools tailored for fire monitoring. These devices record a variety of data that, when put together with other data sets, give us a multifaceted, well rounded, and increasingly accurate, view of the year’s fires.
The Suomi National Polar-orbiting Partnership (Suomi NPP) satellite operated NASA and NOAA detects fires on earth through infrared sensing. Artist rendering via NASA.
These “near real time” fire detection systems fall into two major types: those sensing heat radiating from the Earth’s surface (“hotspots”) and those detecting aerosol emissions (particles released into the atmosphere from burning biomass). A fire’s presence can also be confirmed in some cases via high-resolution imagery, visual data also gathered by satellites.
An orbiting fire monitoring system basically works like this: a satellite instrument detects fires (either via hotspots or aerosol emissions). These fire alerts are relayed to individual organizations, including NASA or INPE, the Brazilian space agency, who process the incoming information to control for noise in the data (such as heat signals from an industrial blast furnace rather than an Amazon fire). The processed data is then sent to a visualization platform, bringing these satellite-based alerts to decisionmakers or the general public on the Internet. Several of these platforms now exist,