The Aqua satellite's MODIS (Moderate Resolution Imaging Spectroradiometer) instrument took this image of the fires in Siberia. The top image shows the full sized false color image of the area highlighting the burn scars from previous fires.
The sliding "before and after" image shows the real and false color images side-by-side for comparison. The left side shows current fires burning denoted by the red spots. These spots show areas where the thermal detectors on the MODIS instrument recognized temperatures higher than background. When accompanied by plumes of smoke, as in this image, such hot spots are diagnostic for fire. Most probably these fires have been set by farmers to clear fields for agricultural use. In April of this year, farmers were setting fires to clear their fields and the fires grew out of control. There was loss of life and quite a bit of devastation from these fires. The false-color (short-wave infrared, near infrared, and green) of the same image on the right shows the burn scars. Most likely some of these scars are from the fires that burned out of control in April.
NASA's Aqua satellite collected this natural-color image with the MODIS instrument on May 13, 2015. Actively burning areas, detected by MODIS's thermal bands, are outlined in red. NASA image courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC. Caption by Lynn Jenner
Explore further: NASA image: Fires in Western Australia April 2015