Wildfires are a natural and, in specific ecosystems, a beneficial phenomenon that helps regenerate vegetation levels and maintain biodiversity. Still, in the last few decades, we have witnessed an alarming increase in the number and intensity of wildfires, where Australian bushfires are only one example. Satellite data images confirm that Australia is by far not the only continent affected by the growing danger of wildfires. The northern hemisphere is equally affected, whereas savanna areas, dependent on wildfires for maintaining their biodiversity, do not get as much as they should, according to satellite data images.
There are multiple reasons behind these shifts, but the quickest (even though somewhat superficial) explanation is the ever-accelerating climate change and human activity. While none of these major contributing factors can be entirely eliminated, satellite data images can be used to analyze current trends and potentially help come up with solutions that could alleviate their impact. Below, we will explain why satellite forest fire detection is an important aspect of Earth observation, and which advances in space data images could improve our understanding of terrestrial ecosystems.
Causes & effects of ever-changing fires
Changes in fires are primarily caused by global warming, but fire increase also contributes its share to accelerating climate change. As yearly temperatures rise, drought periods extend, creating favorable conditions for wildfires. It turn, burning fires release vast amounts of greenhouse gases, including CO2 and methane, into our atmosphere. So, the greenhouse effect increases, contributing to more fires and more gas emissions. Besides, as fires spread, vegetation covers are destroyed, which means there are fewer plants to absorb carbon dioxide.
Human activity also plays a part in the ever-changing satellite fire detection map. In some areas, industrial changes in landscape (i.e., deforestation or expanding agricultural fields) decrease atmospheric moisture and thus, increase the likelihood of fires. In other regions, including the African savanna, agricultural expansion leads to fire decrease because maintained fields arise in traditionally dry areas prone to wildfires. These fields not only increase moisture levels but also act as ‘stoppers’ in the path of wildfires. Once again, this affects local biosystems, further aggravating climate and biodiversity changes. And since the scale of these changes is so enormous, it’s impossible to see the larger picture from the ground — which is where satellite data images come in.
What satellite detects fires?
Several satellites launched by NASA and ESA capture data images that help detect fires, and new earth observation initiatives are always underway. Today, the best satellite data images we get on fires are captured in the infrared light spectrum. So, what does fire look like in infrared? Satellite data images are, of course, different from standard optical imagery we’re used to on Earth — even though some satellites can capture data images in the visible light spectrum, too. However, the visible light spectrum has its limitations for earth monitoring data, particularly when fires are concerned. First of all, smoke creates dense clouds further carried by wind, so it’s very difficult to estimate the actual fire spread from above when these clouds are blocking the camera’s view.
Infrared satellite data images effectively solve this problem because such cameras detect heat waves rather than capture light-based data images. The hotter this wave, the more radiation this area emits. So, satellite data images show bright red spots that get brighter in hotter areas. One of the most effective satellites currently monitoring fire data is NASA’s Moderate Resolution Imaging Spectroradiomete, MODIS. MODIS infrared satellite images of fires allow it to accurately position not only the fire’s location but also obtain image data about its spread, speed, and intensity.
Another great example is the European Space Agency’s (ESA) Sentinel-3, even though its applications go beyond collecting image data about fires. Sentinel is more of a ‘universal’ tech monitoring climate change on land and at sea. But how exactly does climate change monitoring with satellite data images work?
How do satellites show climate change?
Here, a lot depends on satellite equipment and programming. Besides satellite cameras that capture images in the infrared and visible light spectrum, hyper-spectral imagers may be able to discern up to a hundred light wavelengths.
So, each satellite carries specific equipment to collect specific data images; depending on the mission, satellite data images can provide information on vegetation covers, algae oceans, the entire marine ecosystem, yearly temperature fluctuations, moisture levels, and much more. All these satellite data images captured by different spacecraft in different orbits are transmitted to ground stations for data processing and analysis. Combined together, this information deepens our understating of terrestrial processes and climate change — image by image.
But even this is not the limit as far as the potential of satellite data images is concerned. Collaboration between government organizations and private companies, as well as data sharing from scientists, regularly results in new initiatives for collecting climate data, where wildfire images are only part of the larger picture. Satellite data programming has become ever more advanced, and camera capabilities — more impressive. This means that soon enough we may get to see new technologies for detecting wildfires and monitoring climate change.
