Estimates of fire emissions from an active deforestation region in the southern Amazon based on satellite data and biogeochemical modelling

Abstract

Abstract. Tropical deforestation contributes to the build-up of atmospheric carbon dioxide in the atmosphere. Within the deforestation process, fire is frequently used to eliminate biomass in preparation for agricultural use. Quantifying these deforestation-induced fire emissions represents a challenge, and current estimates are only available at coarse spatial resolution with large uncertainty. Here we developed a biogeochemical model using remote sensing observations of plant productivity, fire activity, and deforestation rates to estimate emissions for the Brazilian state of Mato Grosso during [2001][2002][2003][2004][2005]. Our model of DEforestation CArbon Fluxes (DECAF) runs at 250-m spatial resolution with a monthly time step to capture spatial and temporal heterogeneity in fire dynamics in our study area within the "arc of deforestation", the southern and eastern fringe of the Amazon tropical forest where agricultural expansion is most concentrated. Fire emissions estimates from our modelling framework were on average 90 Tg C year −1 , mostly stemming from fires associated with deforestation (74%) with smaller contributions from fires from conversions of Cerrado or pastures to cropland (19%) and pasture fires (7%). In terms of carbon dynamics, about 80% of the aboveground living biomass and litter was combusted when forests were converted to pasture, and 89% when converted to cropland because of the highly mechanized nature of the deforestation process in Mato Grosso. The trajectory of land use change from forCorrespondence to: G. R. van der Werf (guido.van.der.werf@falw.vu.nl) est to other land uses often takes more than one year, and part of the biomass that was not burned in the dry season following deforestation burned in consecutive years. This led to a partial decoupling of annual deforestation rates and fire emissions, and lowered interannual variability in fire emissions. Interannual variability in the region was somewhat dampened as well because annual emissions from fires following deforestation and from maintenance fires did not covary, although the effect was small due to the minor contribution of maintenance fires. Our results demonstrate how the DECAF model can be used to model deforestation fire emissions at relatively high spatial and temporal resolutions. Detailed model output is suitable for policy applications concerned with annual emissions estimates distributed among post-clearing land uses and science applications in combination with atmospheric emissions modelling to provide constrained global deforestation fire emissions estimates. DE-CAF currently estimates emissions from fire; future efforts can incorporate other aspects of net carbon emissions from deforestation including soil respiration and regrowth.

Multi-year MODIS active fire type classification over the Brazilian Tropical Moist Forest Biome

“…Methodologies currently do not consider the fire type explicitly and typically model emissions on the basis of the dominant land cover or vegetation type where active fires are detected (Freitas et al 2005;van der Werf et al 2008;Ichoku and Ellison 2013;Castellanos, Boersma, and Van Der Werf 2014;Mitchard et al 2014). The spatial distribution of the classified fire types may help provide more reliable parameterization of the biomass loading, combustion completeness, and emission factors that differ among the fire types.…”

Spatially Refined Aerosol Direct Radiative Forcing Efficiencies

“…32 NH 3 emissions are described in Park et al, 25 monthly biomass burning emissions are from GFEDv2 33 and biofuel emissions from Yevich and Logan. 34 Dry deposition is calculated using a resistance in series approach 35 and wet losses include in-cloud and below-cloud rainout and convective scavenging.…”

Imaging tropical peatlands in Indonesia using ground-penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization

“…7 and 8). Attenuation in clay-rich areas was to be expected since it is well known than the effectiveness of GPR in peatlands is compromised when electrical conductivity of peat is high due to high electrical fluid conduction or high percent of clay fractions (Theimer et al, 1994).…”

“…Indonesia contains the largest area of the world's tropical peatlands, with estimates ranging from 14.9 Mha (Ritung et al, 2011) to 21 Mha (Wahyunto et al, 2003(Wahyunto et al, , 2004Page et al, 2011). Indonesian peat swamps have been globally significant carbon sinks over the past 15 000 years (Dommain et al, 2014); however, vast areas of Indonesian peatlands are becoming large, long-term sources of greenhouse gases (primarily CO 2 ) for the atmosphere due to deforestation, drainage and/or peat fires (Page et al, 2002;van der Werf et al, 2009). In a recent overview of carbon distribution based on a 2008 inventory, Indonesia was considered the largest source of CO 2 emissions from degrading peat worldwide, with values exceeding other large producers such as China and the United States by almost 1 order of magnitude (Joosten, 2009).…”