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Radiative Transfer Modelling for the characterisation of natural burnt surfaces AO/1-5526/07/NL/HE Recommendations #2c. P. LEWIS 1 , T. QUAIFE 5 , J. GOMEZ-DANS 1,2 , M. DISNEY 1 , M. WOOSTER 2 , D. ROY 3 , B. PINTY 4
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Radiative Transfer Modelling for the characterisation of natural burnt surfacesAO/1-5526/07/NL/HERecommendations #2c P. LEWIS1, T. QUAIFE5, J. GOMEZ-DANS1,2, M. DISNEY1, M. WOOSTER2 , D. ROY3, B. PINTY4 1. NCEO/DEPT. GEOGRAPHY, UNIVERSITY COLLEGE LONDON, GOWER ST., LONDON WC1E 6BT, UK 2. NCEO/DEPT. GEOGRAPHY, KING'S COLLEGE LONDON, STRAND, LONDON WC2R 2LS, UK 3. GEOGRAPHIC INFORMATION SCIENCE CENTER OF EXCELLENCE, SOUTH DAKOTA STATE UNIVERSITY, WECOTA HALL, BOX 506B, BROOKINGS, SD 57007-3510, USA 4. INSTITUTE FOR ENVIRONMENT AND SUSTAINABILITY (IES), EC JOINT RESEARCH CENTRE, VIA E. FERMI 1, TP 440, 21020 ISPRA (VA), ITALY 5. NCEO/DEPT. GEOGRAPHY, EXETER UNIVERSITY,
Overview • EO technology overview (talk 1) • Wildfire detection and quantification • Brief summary of relevant results • ESA and related missions • Modelling fire impacts (talk 2) • Semi-analytical • 3D • Thermal • Linear modelling
Fcc in detection algorithms • Optical detection algorithms: • ‘sensitive measure’ e.g. NDVI/NBR • And set of rules (thresholds etc.) • If view fcc as the sensitive measure, should be able to integrate into detection algorithms in same way • Can use fcc in probabilistic framework • Then obviate need for ‘rules’ beyond probability threshold • Particularly hopeful of this given stability in burn signals observed
Post fire analysis • NIR/MIR signal increases over week/weeks in savannas • If model operates as intended, expect: • Fcc remain constant over time • a0/a1 parameters vary (char dissipation)
Post fire analysis • Such analysis quite complex • Need to do careful BRDF modelling post fire • But would suggest that fcc measure should have some tolerance to post-fire observation timing • Since a0/a1 quite stable, expect to observe some consistent dynamics in feature space as fn of time after fire
Post fire analysis • Also, vegetation regrowth post fire should have poor fit to spectral model • so should spot this
recommendations • fcc approach should be investigated for detecting fire-affected areas from optical data • extend to spatio-temporal modeling of fires as part of detection algorithms and concepts for multi-sensor merging. • Target variables should move beyond estimation of a pixel count of fire-affected areas, to measures including fcc, fire size, and rates of spread. • temporal dynamics of the fcc signal should receive some attention.