Algorithm


FILDA-2 is generated primarily on the VIIRS Level-1B calibrated radiance and geolocation dataset. Table 1 summaries detailed information of the VIIRS band usage:


Flowchart of the FILDA-2 algorithm



Table 1. Characteristics of the VIIRS Bands used in the FILDA-2
Band Number/Gain Wavelength (µm) Nadir resolution Primary application in FILDA-2
DNB, multiple 0.7 ~ 0.9 742 × 742 Fire Detection, VEF calculation
M12, single 3.74 742 × 766 Cloud mask
M13, dual 4.05 742 × 766 Fire Detection, FRP calculation
M15, dual 10.76 742 × 766 Cloud mask
M16, single 12 742 × 766 Cloud mask
I4, single 3.74 371 × 387 Cloud mask, fire detection
I5, single 11.45 371 × 387 Cloud mask, fire detection


Other ancillary datasets are listed as follows:

  • The standard S-NPP VIIRS Black Marble Nighttime Light product (VNP46A1) is used for generating a global surface light climatology.
  • Temperature data from the Goddard Earth Observing System Forward Processing (GEOS-FP) forecast product as part of the surface flux diagnostics (tavg1_2d_flx_Nx) to aid in the processing of an internal nighttime cloud mask.
  • The MODIS Terra and Aqua combined land cover product (MCD12Q1) is used to specify the land surface type of each fire pixel.
  • A peatland database is included to specifically designate peatland fire pixels.
  • A global gas flaring dataset is used to identify gas flaring pixels detected by FILDA-2.
Illustration of land surface types used in FILDA-2 for the year 2018, including the International Geosphere-Biosphere Programme (IGBP), Peatland, and Gas Flaring databases from multiple sources.