Over the past month, dozens of wildfires have scorched large swaths of land in California, Oregon and Washington state, killing more than 30 people and suffocating much of the western United States in smoke. While photographs have circulated online showing the apocalyptic orange sky, satellites orbiting Earth carry different instruments that can provide not just images, but a wealth of additional information needed to monitor the fires.
Record temperatures, high winds and thunderstorms created the dangerous conditions that allowed fires across the western United States to ignite and spread. The plumes of smoke from the fires are so large that they have crossed the United States, even reaching New York on the east coast. According to the Copernicus Atmosphere Monitoring Service (CAMS), the smoke is expected to reach Europe this weekend.
In this dramatic image, captured by the Copernicus Sentinel-3 mission on September 16, fires can be seen burning on the west coast of the United States, with smoke moving east across the country. Meanwhile, Hurricane Sally is visible making landfall on the east coast. Hurricane Sally slammed into Gulf Shores, Alabama on Wednesday, with recorded winds of around 100 mph (169 km/h), before developing into a tropical depression.
While the image was captured by the mission’s Ocean and Land Color Instrument, which provides camera-like images, the mission’s Sea and Land Surface Temperature Radiometer records hotspots of ‘fire. The instrument works like a thermometer, measuring thermal infrared radiation to take the temperature of Earth’s land surfaces.
This information is used to detect and monitor the heat emitted by fires. These two dedicated fire channels are used to compile the World Fire Atlas.
Animation shows the number of fires detected between August 1 and September 14, 2019, compared to August 1 and September 14, 2020.
These measurements were taken by the Copernicus Sentinel-3A at night only. Comparing fire activity with the previous year, the data suggests there were hundreds more fire hotspots in 2020 compared to the same time last year.
The Copernicus Sentinel-5P satellite, dedicated to monitoring air pollution, has detected the increase in carbon monoxide concentrations along the west coast.
The hotspots visible in the image show the precise locations of wildfires, which have been identified in bold.
While carbon monoxide is commonly associated with traffic, the increase in concentrations comes from fires. Once in the air, carbon monoxide can cause problems for humans by reducing the amount of oxygen that can be carried in the blood.
Optical images captured by the Copernicus Sentinel-2 mission were also used to image the fires. Each of the two satellites carries a high-resolution camera that images the Earth’s surface in 13 spectral bands.
The image below, captured on September 9, 2020, shows some of the wildfires over Oregon. The view on the left shows the affected area captured by the camera-like instrument on board the satellite, while the composite on the right uses the SWIR bands from the same instrument which penetrate the smoke from the fire and provide a clearer view of the front fire and area affected at the time of acquisition.
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Provided by the European Space Agency
Quote: Images of US West Coast on fire (September 21, 2020) Retrieved March 29, 2022 from https://phys.org/news/2020-09-images-west-coast.html
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