Fire severity is a measure of the magnitude of the immediate fire impacts on vegetation (aboveground) and soils (belowground) through the loss or decomposition of organic matter (adapted from Keeley, 2009). As a consequence, the evaluation and prediction of fire severity is of interest to scientists and fire managers given its ramifications to ecological integrity and forest management. It also can aid in developing emergency rehabilitation and restoration post-fire plans. The proposed methodology is recommended for assessing the fire severity of large areas that are affected by wildfires and was performed by using Sentinel-2 data. NIR and SWIR bands of Sentinel-2 (Bands 8A and 12) were used to calculate the Normalized Burn Ration (NBR) for the pre and post-fire images. Composite masked images (after applying cloud masks procedures) for pre and post NBR were built using the mean reflectance values of the unmasked pixels of 20m. The Delta NBR (dNBR) is then determined through the difference between the pre and post-fire NBR composites. Finally, dNBR is classified according to the severity thresholds adopted by Key & Benson (2006).
|Class||dNBR range (multiplied by 1000)|
|Unburned or Regrowth||< 100|
|Low severity||100 - 270|
|Moderate low severity||270 - 440|
|Moderate high severity||440 - 660|
The severity for each fire is calculated after 30 days of the date of the fire.
Keeley, J.E., 2009. Fire intensity, fire severity and burn severity: a brief review and suggested usage. International Journal of Wildland Fire 18 (1), 116–126. https://doi.org/10.1071/WF07049
Key, C.H., Benson, N.C., 2006. Landscape Assessment (LA). In: Lutes, D.C., Keane, R.E., Caratti, J.F., Key, C.H., Benson, N.C., Sutherland, S., Gangi, L.J. (Eds.), FIREMON: Fire Effects Monitoring and Inventory System, General Technical Report (GTR). U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, p. LA-1-55. https://purl.org/INRMM-MiD/z-B4PCNQM6