Abstract
Fires are complex processes having important impacts on biosphere/atmosphere interactions. The spatial and temporal pattern of fire activity is determined by complex feedbacks between climate and plant functioning through and biomass desiccation, usually estimated by fire danger indices (FDI) in official fire risk prevention services. Contrasted vegetation types from fire-prone Brazilian biomes may respond differently to soil water deficit during the fire season. Then, we propose to evaluate the burned area (BA)/FDI relationship across Brazil using most common FDIs and the main BA products from global remote sensing. We computed 12 standard FDIs- at 0.5° resolution from 2002 to 2011 and used the monthly BA from four BA datasets—from the MODIS sensor (MCD45A1), the MERIS sensor (MERIS FIRE_CCI), the Global Fire Emission Database version 4 (GFED4) and version 4s including small fires (GFED4s). We performed a Principal Component Analysis (PCA) on the coefficients of determination (R2) of the FDI/BA relationship to investigate the biome specificities of Brazilian biomes and the sensitivity to BA datasets. Good relationships (R2 > 0.8) were observed for all BA datasets, except SPEI (R2 < 0.2). We showed that FDIs computed from empirical water balances considering a lower soil capacity are more correlated to the seasonal pattern of fire occurrence in the Cerrado biome with contrasted adjustments between the western (early drying) and eastern part (late drying), while the fine fuel moisture index is more correlated to the fire seasonal pattern in Amazonia. The biome specificities of the FDI/BA relationship was evaluated with a general linear model. High accuracies in the biome distribution according to the FDI/BA relationship (>50%, p < 0.001) was observed in Amazonia and Cerrado, with lower accuracy (<32%, p < 0.001) in the Atlantic Forest and Caatinga. These results suggest that the FDI/BA relationship are biome-specific to explain the seasonal course of burned in Brazilian biomes, independently of the global BA product used. Selected FDIs should be used for fire danger forecast in each Brazilian biome.
Highlights
Fire is an abiotic process initiated by natural lightning or human-induced fire settings, and spreads across landscapes, with important consequences on many ecological processes of vegetationClimate 2017, 5, 42; doi:10.3390/cli5020042 www.mdpi.com/journal/climateClimate 2017, 5, 42 functioning and dynamic in fire prone biomes [1]
Relationship (>50%, p < 0.001) was observed in Amazonia and Cerrado, with lower accuracy (
To figure out which FDIs had a better correlation for each grid cell and assemble the grid cells with similar FDI/BA relationship, we performed a Principal Component Analysis (PCA) on all the FDI/BA R2
Summary
Fire is an abiotic process initiated by natural lightning or human-induced fire settings, and spreads across landscapes, with important consequences on many ecological processes of vegetation. Fire occurrence is driven by different constraints [6], where the spatial pattern of weather conditions and fuel resource availability has a key role [7] It has long ago been emphasized the importance of microclimate (mainly solar radiation, air temperature and relative humidity) effects on fuel load and fuel moisture for flammability of tropical vegetation [7,8], mostly through drought events controlling the seasonality of burned area. Different approaches have been developed to estimate the potential fire risk, using various numerical or qualitative indices in the fire danger rating systems These indices are non-destructive measures developed to evaluate the fuels stand’s proneness to fire in terms of weather conditions, drought hazard or fire behavior. Fire is mostly used for land clearing after cutting of existing vegetation [38]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
