NASA FIRMS recently added the VIIRS Black Marble Nighttime data products as the ultra-sensitivity of the Day/Night band allows large/hot actively burning areas at night to be detected (ahead of the daytime overpass). The products include both the Nighttime At Sensor Radiance and Nighttime Blue/Yellow Composite products from S-NPP and NOAA-20. These data layers are only available in the ADVANCED MODE under the Dynamic Imagery accordion and should be used with caution so as not to confuse city lights or reflected moonlight with fires.  

Similar to using the daytime corrected reflectance imagery from MODIS and VIIRS to help interpret wildfire characteristics during the day including wildfire extent, wildfire smoke, and cloud prevalence which may impact detection, the black marble nighttime imagery can be helpful for interpreting wildfire characteristics during the nighttime. The black marble nighttime imagery product is created from a unique Day Night Band (DNB) that is included on the VIIRS instruments aboard S-NPP and NOAA-20. The DNB is a panchromatic band that detects very small amounts of visible light & NIR (resulting from reflected moonlight or sources such as city lights that emit visible light) over a wide wavelength from 500-900nm. The ultra-sensitivity of the VIIRS Day/Night band allows actively burning areas at night to be detected. The sensor resolution of the DNB is 750m and the imagery resolution is resampled to 500m. 

Nighttime At Sensor Radiance Example

The example below shows a number of wildfires that occurred near Cascade, Idaho (the Goat and Lava fires) in early September 2024. In the image on the left of the NOAA-20 black marble nighttime at-sensor radiance imagery for 8th September, the extent of the wildfires detected at nighttime can be seen. In the image on the right of the NOAA-20 black marble nighttime at-sensor radiance imagery for 9th September presented at the same scale, the massive expansion of the fires can be seen. To view this example in FIRMS, use this link to display the NOAA-20 black marble nighttime at-sensor radiance imagery for 8th September over the Goat and Lava fires, and use the time slider at the bottom of the map to toggle forward to 9th September. The sensor resolution is 750m, imagery resolution is 500m.

Screenshot from FIRMS US/Canada showing NOAA-20 black marble nighttime at-sensor radiance for 8th September 2024 (top) and for 9th September 2024 (bottom), highlighting the rapid growth of the Goat and Lava fires.

Nighttime Blue/Yellow Composite Example

The VIIRS S-NPP and NOAA-20 Black Marble Nighttime blue/yellow composite imagery is a false composite that uses the VIIRS at-sensor radiance from the DNB and the brightness temperatures from M15, a longwave infrared band.  This blue/yellow composite can be useful for assessing light emitted from city lights as well as wildfires at nighttime. City lights and wildfires appear in shades of yellow in IR, and nighttime clouds appear in shades of blue. During bright moonlight conditions, moonlight reflected from cloud tops and the land surface may also provide a yellow hue to those features. The example below shows a NOAA-20 Black Marble Nighttime blue/yellow composite imagery sequence for the Park Fire that occurred near Chico, California in July/August 2024. The imagery sequence includes 24th, 25th, 26th, 27th, 29th July & 6th August. 

Series of screenshots from FIRMS US/Canada for 24th, 25th, 26th, 27th, 29th July & 6th August 2024, showing the NOAA-20 Black Marble Nighttime blue/yellow composite imagery sequence for the Park Fire that occurred near Chico, California in July/August 2024 . 

To view this example in FIRMS, use this link to display the NOAA-20 black marble nighttime blue/yellow composite imagery for July 24th over the Park Fire, and use the time slider at the bottom of the map to toggle forward to July 25th and onwards to see the progression of the fire based on the light emitted at nighttime. Clouds, which can potentially affect fire detection, can be discerned, and are apparent, over the fire on July 27th (additional information on the impact of clouds is available in this NASA Earthdata article. 


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