Determinants and predictability of global wildfire emissions 1Physical Geography and Ecosystem Analysis, Lund University, Sölvegatan 12, 22362 Lund, Sweden
01 Aug 2012
2KIT/IMK-IFU, Kreuzeckbahnstr. 19, 82467 Garmisch-Partenkirchen, Germany
Received: 02 Dec 2011 – Published in Atmos. Chem. Phys. Discuss.: 06 Feb 2012 Abstract. Biomass burning is one of the largest sources of atmospheric trace gases and
aerosols globally. These emissions have a major impact on the radiative
balance of the atmosphere and on air quality, and are thus of significant
scientific and societal interest. Several datasets have been developed that
quantify those emissions on a global grid and offered to the atmospheric
modelling community. However, no study has yet attempted to systematically
quantify the dependence of the inferred pyrogenic emissions on underlying
assumptions and input data. Such a sensitivity study is needed for
understanding how well we can currently model those emissions and what the
factors are that contribute to uncertainties in those emission estimates.
Revised: 08 Jun 2012 – Accepted: 23 Jul 2012 – Published: 01 Aug 2012
Here, we combine various satellite-derived burned area products, a
terrestrial ecosystem model to simulate fuel loads and the effect of fire on
ecosystem dynamics, a model of fuel combustion, and various emission models
that relate combusted biomass to the emission of various trace gases and
aerosols. We carry out simulations with varying parameters for combustion
completeness and fuel decomposition rates within published estimates, four
different emissions models and three different global burned-area products.
We find that variations in combustion completeness and simulated fuel loads
have the largest impact on simulated global emissions for most species,
except for some with highly uncertain emission factors. Variation in
burned-area estimates also contribute considerably to emission uncertainties.
We conclude that global models urgently need more field-based data for better
parameterisation of combustion completeness and validation of simulated fuel
loads, and that further validation and improvement of burned area information
is necessary for accurately modelling global wildfire emissions. The results
are important for chemical transport modelling studies, and for simulations
of biomass burning impacts on the atmosphere under future climate change
Citation: Knorr, W., Lehsten, V., and Arneth, A.: Determinants and predictability of global wildfire emissions, Atmos. Chem. Phys., 12, 6845-6861, doi:10.5194/acp-12-6845-2012, 2012.