By Eric Sagara.
Flames raced through Northern California last summer, destroying thousands of homes and killing four people. At Reveal, we wanted to tell the story of how three wildfires spread so quickly, so we turned to satellite data.
As different satellites scan the globe, they gather a variety of information. That data gathering, known as remote sensing, regularly is used by scientists, and the data is free and publicly available.
The use of satellite data is a fairly recent tool in most newsrooms.
We used it last year to show how California’s drought affected vegetation health and how that, in turn, affected the state’s wildfire season. For that project, we worked with the MODIS sensor on NASA’s Terra satellite. This time, we turned to Landsat 8, a joint satellite mission between NASA and the U.S. Geological Survey. Both satellites capture imagery from a wide spectrum of light stretching beyond what the eye can see. But Landsat 8 has a much finer spatial resolution than MODIS, which means you can see more details in the images.
Landsat 8 scans Earth every 16 days. We selected imagery from four days from late July through September. These days were chosen primarily based on how much cloud cover obscured the area where fires were burning.