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CTCD Fire Activities. P. Lewis, L. Rebelo, I. Woodward, P. Bowyer, B. H eung, M. Wooster, D. Roy. Fire Workpackage. Aim: Provide improved estimates and model of global C-release from fires Identification of existing Burn-Affected Area Datasets Calibration and Testing of SDGVM Fire Module
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CTCD Fire Activities P. Lewis, L. Rebelo, I. Woodward, P. Bowyer, B. Heung, M. Wooster, D. Roy
Fire Workpackage • Aim: • Provide improved estimates and model of global C-release from fires • Identification of existing Burn-Affected Area Datasets • Calibration and Testing of SDGVM Fire Module • End-to-end testing via Satellite C-emission estimates • Generation and Testing of Burn-Affected Area Datasets and Associated Products
Issues • Many EO datasets single year only • Though increasing production of longer time series datasets • Active fire detection underestimates fire activity • Non-geo-located products double count fires at swath edges • Burn-affected area mapping needs to account for BRDF effects • General lack of ‘validation’
Calibration and Testing of SDGVM Fire Module • regression models based on the simulated SDGVM result • plant function types, temperature, surface soil content and precipitation • Currently using Global Burn Area (GBA) and World Fire Atlas (WFA) data • fitted to estimate the number of fire occurs in a 1 degree pixel.
Calibration and Testing of SDGVM Fire Module • Moved to 2-step model: • Logistic model of Fire Occurance • Model to estimate number of fires • Model testing • Canadian large fire data base • SDGVM run to simulate a fraction of the area burn in Canada between 1959 and1999. • data ½ degree resolution. • Initial analysis: • SDGVM fire estimated burnt area is a factor ~3 greater than the LFDB result. • Also shows less variation • does not pick up the extreme years • the time-series from 1958 to 2000 for the SDGVM and the LFDB show little correlation. Current efforts are to understand the possible reasons and hence how to improve the SDGVM prediction. • Demonstrates requirement for further work on model development and requirement for observations
End-to-end testing via Satellite C-emission estimates • Wooster producing C-emission estimate from Fire Radiative Energy • FRE from Meteosat Seviri (2004+) • And Boreal region MODIS (2000+)? • Diurnal activity from Seviri • Allows end-to-end testing of models • And estimation of other terms when combined with satellite burn affected area
Generation and Testing of Burn-Affected Area Datasets and Associated Products • Working with David Roy in development and testing MODIS burn-affected area product • Testing alternative methods • Examining derived products in S. Africa • Fire return frequency • Seasonality
Fire Frequency • 40% of the land surface burned, with 6% (area of approximately 131,420km ° ) burning during each of the five annual fire seasons. • Higher fire frequencies identified in savanna and grassland ecosystems, with shrublands and deciduous broadleaf forests burning less frequently. • Fire return intervals indicate that locations which burn every year do so at the same time each year. • These areas also have a distinct spatial pattern and are predominantly located in the northern section of Angola, southern Zaire and northern Zambia, as well as in a belt along the Namibia/Angola/Botswana borders.
Spatial extent • Between 27% and 32% of the study area has burned during each of the five years of observation. This equates to an area of approximately 610,000 to 690,000km2 . • The distribution of burning within each of the main vegetation types is similar from year to year, with a much larger proportion of deciduous broadleaf forests, woody savannas and savannas burning each year in comparison to shrublands and grasslands.
Summary #1 • Fire models (e.g. SDGVM) based on understanding of ecology and fire interactions • Very limited datasets previously available for testing • EO provides potential for much greater spatial sampling and analysis • FRE provides potential for end-to-end testing of model and C-release
Summary #2 • Many EO datasets generated • Active fire detection underestimates activity and depends on time of observation • New generation of burn-affected area products under generation provide most high quality information • But need furter testing/validation • Rich source of information available for analysis • But over limited time period
Active Fire Datasets: Global • MODIS Thermal Anomolies (NASA) • 1 km resolution 2000+ • 2x daily (morning/afternoon) • High confidence of detection if fire observed • Also MODIS Rapid Response System • World Fire Web (GVM/JRC) • 0.5o resolution AVHRR 1996-2001 • Errors of commision & omission • Different processing methods used at different receiving stations • Frame overlap issues • Discontinued • World Fire Atlas (ESA) • 1995-2004+ night time (A)ATSR • Frame overlap issues • Revisit period ~3 days
Active Fire Datasets: Regional • TRMM VIRS Monthly Fire Product • 0.5o resolution, 1998-2004+ • 38oS to 28oN • 2+ observations/day • Moderate detection capability with higher probability of detection in non-forest land cover classes • GOES-8 ABBA Fire Product • 4km x 4km, 1994-1997 • 4x/day • Coverage S. America • AVHRR Fire Atlas (ESA ESRIN) • S. Hemisphere, day time AVHRR, 1993 (1992-1994 Africa) • High confidence detections only
Burn Affected Area (Global) • GLOBSCAR (ESA ESRIN) • 1 km, year 2000, monthly or annual • Daytime ATSR-2 data (3 day repeat) 10:30 am • 2 algorithms: combination gives low error of commission • Particular underdetection in United States (open shrubland and grasslands), Australia (open shrublands), Zimbabwe (croplands) and Brazil (broadleaf evergreen forest) • GBA-2000 (JRC/GVM) • 1 km, year 2000 SPOT VGT • Regional algorithms used • R2 comparisons with TM data from 0.4 (Mozambique) to 0.99 (Botswana) • False detections in sub-Saharan Africa include false detections due to flooding of non-permanent water features as well as due to the presence of hot dark rocks. (but small proportion) • Only burned areas of at least 400ha in size output • MODIS Burned Area product (NASA) • David Roy will discuss • 500m resolution day of burn, monthly product 2000+ • Africa testing: 99.7% correct detections, and lowest in Mozambique (74.3%) (overall R2 0.8) • GLOBCARBON • Steve Plummer will discuss • ERS-2 / ATSR-2, ENVISAT / AATSR, and SPOT /VEGETATION. ENVISAT / MERIS • global monthly maps of burnt areas for the period 1998-2007 in 10 km, 0.25° and • 0.5° resolution • based on the experience of both GLOBSCAR and GBA-2000. • CTCD testing dataset
Burn Affected Area (Regional) • Canadian Forest Service (Large fire database) • 1959-1999+, fires > 200ha • Small proportion of fires but 97% of total area burned • the date (year, month, day, start date, detect date), location (latitude, longitude, Province), cause, size and ecozone of each fire detection. • Mouillot’s Database • 20th Century fire, 1o resolution • Reconstructed from various data sources (incomplete) uses ATSR for recent fires