The global burned area product from VIIRS S-NPP has been added to FIRMS. This NASA standard science product (VNP64A1) provides continuity to the MODIS-generated NASA standard science burned area product (MCD64A1) and uses an adaptation of the same algorithm used to generate MCD64A1 Collection 6.1. While the native spatial resolution of the VIIRS input bands is coarser than those of MODIS, VNP64A1 is produced at the same 500 m resolution, and on the same sinusoidal grid as MCD64A1. The VIIRS product is also compiled and distributed as a monthly product.
Burned areas are characterized by deposits of charcoal and ash, removal of vegetation, and alteration of the vegetation structure. The algorithms used to generate both MCD64A1 and VNP64A1 takes advantage of these spectral, temporal and structural changes by identifying rapid changes in a time series of the daily surface reflectance imagery. As with the MODIS burned area product, the VIIRS burned area product requires a continuous calendar month of daily surface reflectance imagery and active fire detection data plus active fire detection data for the 10 days prior and after the target month to identify areas burned. This requirement and other factors result in a 5 month lag before the product is available. While the MODIS product is available from November 2000 onwards, following the launch of the Terra satellite which carries the MODIS instrument in late 1999, the VIIRS product is available from March 2012, following the launch of the SNPP satellite which carries the VIIRS instrument in October 2011.
The product is accessible through the ADVANCED MODE and the BURNED AREA MODE within FIRMS fire map. The VIIRS burned area product uses the updated burned area interface, that was described in the previous blog (link) so users can simultaneously display and compare individual monthly burned area products. Figure 1 shows the monthly burned area for the MODIS and VIIRS products for 2024. Users can also view the monthly products aggregated into annual datasets, for one to three user-selected years. Figure 2 shows the annual burned area for the MODIS and VIIRS products for 2023 for areas of Alberta and Saskatchewan in Canada. Figure 3 provides a larger scale example comparing the MODIS and VIIRS burned area products in the context of reflectance imagery. Figure 4 shows the annual burned area for parts of the Northwest Territories and Northern Saskatchewan based on the VIIRS product for 2023 and 2014. The default opacity setting for each layer is 70% so that users can more easily identify areas that reburned. A combined burned area product based on observations from VIIRS aboard both SNPP and NOAA-20, is planned.
Figure 1: monthly burned area for the MODIS and VIIRS products for 2024, displayed on the Firefly background in the ADVANCED MODE of FIRMS Global. FIRMS Global.
Figure 2: Annual burned area based on the MODIS product (yellow) and VIIRS product (blue) for 2023 for areas of Alberta and Saskatchewan in Canada, displayed using the BURNED AREA MODE of FIRMS Global. FIRMS Global
Figure 3: Annual burned area based on the MODIS product (yellow) and VIIRS (blue) for fires in southern Northwest Territories and northern Alberta. The left panel displays the S-NPP VIIRS false color composite with burned areas appearing in dark red with the other panels displaying the MODIS and VIIRS burned area products.
Figure 4: annual burned area for parts of the Northwest Territories and Northern Saskatchewan based on the VIIRS product for 2023 and 2014, displayed using the BURNED AREA MODE of FIRMS US/Canada. FIRMS US/Canada