G. Roberts, M. J. Wooster and G. Perry Department of Geography, King’s College London Fire Radiative Energy: Ground and Satellite Observations Geostationary Fire Monitoring Applications Workshop March 23-25, 2004, EUMETSAT

Remote Sensing Fire Radiative Energy (FRE) Interested in FRE from SEVERI : Can be used to estimate rates and total amounts of biomass combusted using observations of emitted thermal energy released during vegetation fires This then acts as the basis for carbon and trace gas/aerosol emissions inventories

UK Fieldwork Spectrometer MIR camera video Digital Scales Fuel Bed Mini Met Station 12 m tower

FRE inter-comparison: MIR camera vs spectroradiometer Spectroradiometer MIR camera

Rate of FRE Release vs Rate of Mass Loss Increasing Time

Fire Radiative Energy vs. Mass Combusted Very good relationship – FRE well related to mass combusted BUT only ~ 2000 KJ radiated per kg burnt Net heat yield quoted at ~ 16,000 KJ/kg 15 ± 7 % of theoretically released energy appears to be actually radiated R 2 = 0.964

FRE Derivation in the MIR FRE derived as a function of MIR spectral radiance: Advantages : Linear computationally efficient alterations can be applied later e.g. atmospheric correction One spectral channel not sensor specific Algorithm : active fire detection and background characterisation FRE derived per pixel and per fire L MIR,h = ‘fire’ pixel MIR spectral radiance  MIR = ‘fire’ pixel MIR emissivity a = constant from Planck fn approx. A sampl = ground-pixel area (m²)

SEVERI and MODIS SEVERI (12:57 – Sept 1 st 2003)MODIS (12:20 – Sept 1 st 2003) Green : MIR channel Yellow : Detected active fires

SEVERI and MODIS FRE R 2 = 0.74

Total emitted energy (MW) = (9.7 MW/sec) Total Biomass Combusted (Kg) = (4.9 Kg/sec)

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SEVERI MIR saturation Saturation point Initial detection Daytime: Fires detectable down to ~ 0.5 to 1.0 hectares (assume 800 K) Nighttime: Somewhat smaller (maybe to ½ this size)

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BUT SOME QUESTIONS REMAIN………. Do ground-based and spaceborne FRE agree ? Do very large fires have similar % of energy released as radiation? Cloud cover problem coupling FRE & burned area products ? fit a model to available samples or interpolation ? Active fire detection Couple temporal and spatial domains Background characterisation Fire detection

Acknowledgements Thanks to : Rothamsted Agricultural Research Botswana Wildlife Service DLR EUMETSAT NASA Staff and students at Kings/UCL

Current Approaches to Emission Current Approaches to Emission Inventory Based on estimates of total biomass combusted (M) –converted into emissions estimate via ‘emissions factors’ Biomass = Burnt * Biomass * Burning Burnt (M) Area Density Efficiency Difficulty reliably estimating biomass density & burning efficiency –uncertainty propagates through to estimates of M Andreae and Merlet (2001) demonstrate order-of-magnitude difference between fire frequency and EO-approaches and suggest a new route maybe needed to enhance the existing methodologies.