Allan Spessa 1,2 , Kirsten Thonicke 3 , Colin Prentice 3 Simulating Climate-Vegetation- Fire Interactions & Emissions: Regional Applications of the LPJ-SPITFIRE Model 1. Max Planck Institute for Biogeochemistry, Jena, Germany 2. Hadley Centre (from 2006) 3. Marie Curie Fellow, Bristol University 4. QUEST & Bristol University
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Allan Spessa 1,2, Kirsten Thonicke 3, Colin Prentice 3 Simulating Climate-Vegetation-Fire Interactions & Emissions: Regional Applications of the LPJ-SPITFIRE.
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1. Max Planck Institute for Biogeochemistry, Jena, Germany 2. Hadley Centre (from 2006)3. Marie Curie Fellow, Bristol University4. QUEST & Bristol University
Key Research Questions for LPJ-SPITFIRE
1. Assess long-term changes in vegetation composition and above-ground carbon due to altered fire regimes, at regional and global scales.
2. Quantify emissions of different trace gases from biomass burning (CO2 etc), at regional and global scales.
3. Examine effects of regional climate phenomona (e.g. El Nino) on fire activity, vegetation, and emissions.
4. Investigate changes in human-caused ignition patterns.
Fire in the Earth Systempopulation
density
FIRE MODEL SIMULATES:Number of Fires, Area Burnt, Fire Intensity, Crown Scorch, Plant Mortality, andEmissions of CO2, CO, CH4, VOC, NOx & TPM. Temporal scale = 1 day.Spatial scale = 0.5 deg (flexible).
1) Human and lightning-caused ignition rates. Gridcell variable (calibration data limited).
2) Surface rate of spread based on Rothermel family of models. ROS is directly proportional to energy produced by ignited fuel, and also wind. ROS is inversely proportional to the amount of energy required to ignite fuels.
3) Litter moisture = f (fire danger index);
4) Grass phenology (‘green-up’ and curing);
5) Raingreen tree phenology*;
6) Fire intensity (independent of rate of spread);
7) Fuel combustion (by fine and coarse fuel classes);
8) Tree mortality & crown fires = f (scorch height, cambial kill; vegetation-specific attributes);
9) Land cover change* adjust fire activity and emissions to natural vegetation regions, and
Emissions (tonnes/km2) × trace species × PFT × period (day, month or year).
* Not yet implemented
Key features of LPJ-SPITFIRE
• Beta version undergoing validation.
• Long-term validation data on fire activity collated from several regions, covering most biomes (Iberian Peninsula, North Germany, Russia and Central Asia, Africa, Australia, Western USA,
Canada, Borneo, Amazonia).
• Data from various sources: satellite and ground observations, processed to a common format for model checking.
Simulate seasonal changes in ignition sources e.g. early- vs late- dry season burning in tropical savannas.
Revisit calibration of population density with fire activity for human-caused ignitions. Consider joint effects of land use change. (Data sources? GLC 2000, Ramankutty-Foley, Goldewijk HYDE 3.0)
Incorporate land use effects directly into the model e.g. grazing (tropical savannas) or deforestation rates (humid tropical forests).
Simulate variability in lightning-caused fires (Data source? Optical Transient Detector, Christian et al. 2003).
Linking LPJ-SPITFIRE to Remote Sensing Studies of Emissions
Total amount of Emissions (E) typically described by the following equation (Seiler and Crutzen 1980),
M = ∑ ( [A]ijt x [B]ij x [C]ijt x [EF]k), where
• A is the monthly (t) burned area (km2) at location ij;• B is the fuel load (tonnes/km2) expressed ona dry weight (DM) basis; • C is the fraction of available fuel which burns (the combustion factor); and• EF is the Emission Factor for the kth trace species (g/kg or tonnes/km2).
Estimating Total Emissions
Reducing uncertainty in emission estimates
• New long-term satellite products becoming available (e.g. GLOBCARBON Plummer et al. in progress, Perriera et al. in progress., Camaro et al. 2005 GCB + many others).
• Fine temporal &/or spatially resolved optical (e.g. LANDSAT-TM, MODIS ‘Terra’ & ‘Aqua’, Meteosat) for separate emission calculations and testing above products. But, large uncertainties remain with respect to…
• How much biomass is available for burning through space and time. (Litter production, crown biomass.)
• Relative amount of fine fuels and coarse fuels. (Flaming vs smouldering combustion.)
• Fuel moisture. (Flaming vs smouldering combustion.)
• What proportion of biomass is combusted. (Fire intensity.)
Thank you for your attention
Northern Australia:Observed Number of Fires
(AVHRR FAA data, DOLA)
Northern Australia:Simulated Number of Fires (LPJ-SPITFIRE)