Multidecadal satellite-derived Portuguese Burn Severity Atlas (1984 -2022)

The Portuguese burn severity atlas (1984 -2022) provides satellite-derived burn severity estimates of each historical fire with its start and end dates recorded and equal to or larger than100 ha for fires from 1984 to 2022 in Portugal. The fire perimeters are provided by the Instituto da Conservação da Natureza e das Florestas (ICNF) (https://sig.icnf.pt/portal/home/item.html?id=983c4e6c4d5b4666b258a3ad5f3ea5af). Landsat imagery is applied for the creation of this atlas. The burn severity indices applied within this atlas are differenced Normalized Burn Ratio (dNBR), Relative differenced Normalized Burn Ratio (RdNBR), Relative Burn Ratio (RBR), and index combining dNBR with enhanced vegetation index (dNBR-EVI).

Since 1984 to 2022, the total burned area recorded in Portugal is 4.85 million ha. Only valid fires, which are fires equal to or larger than 100 ha with known dates, were considered for the burn severity estimates. The total area of valid fires is 3.29 million ha. The Portuguese Burn Severity Atlas provides estimates for 3.17 million ha, accounting for 65% of all fires and 96% of valid fires.

The Portuguese burn severity atlas is organized in subfolders, each entitled as the corresponding year and containing shapefile, maps and a table with details on pairs of images used for burn severity estimates. Within each subfolder, the following data are stored:

 the annual fires’ perimeters shapefile (.dbf, .prj, .shp, .shx)

dNBR map (.tiff)

RdNBR map (.tiff)

RBR map (.tiff)

dNBR-EVI map (.tiff)

confidence map: average “SUITABILITY in each pixel within the area of the fire (.tiff)

comma separated value (.csv) file containing details on the pair of images used for burn severity estimates (year, ID, iteration number, pre-fire time lag(day), pre-fire cloud%, pre-fire suitability (%), post-fire time lag (day), post-fire cloud%, post-fire suitability(%), confidence in the iteration(%), area with dNBR estimation(ha), area of fire (ha), fire i number (to refer in GEE code), dNBR offset value, RdNBR offset value, RBR offset value, and dNBR-EVI offset value).

To the best of our knowledge, Portuguese Burn Severity Atlas is the first open access atlas providing burn severity estimates of historical fires for an entire European country, in this case, Portugal, with 38 years of coverage. Target audience who can benefit from this atlas can be policymakers at national levels, field managers, project managers, and agency and academic researchers.

*** The second version of this atlas provides updated fire data and burn severity estimates of fires from 1984 to 2000 with corrected dates area equal or larger than 100 ha. Moreover, for 2012, aside from burn severity estimates provided via imagery from Terra abroad Moderate Resolution Imaging Spectroradiometer (MODIS), Landsat7-derived maps are included.