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Published byEdmund Wiggins Modified over 9 years ago
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Radiative Transfer Modelling for the Characterisation of Natural Burnt Surfaces ITT 5526: Algorithm Validation Plan (AVP) Prof. Philip Lewis 1, Dr. Mathias Disney 1, Prof. Martin Wooster 2, Dr. Bernard Pinty 3, Prof. David Roy 4 1. UCL; 2. KCL; 3. JRC; 4. SDSU
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Optical fieldwork Rationale – Generation of 3D RT models Key structural and radiometric measurements of canopy before/after burn Spatial distribution of vegetation – Validation/testing of 3D RT models Characterise before/after signal to simulate EO signal & compare with EO data – Site selection encompasses variations of both cover type and fire regimes
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Sites: Satara Models
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Sites: Pretoriuskop Models
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Sites: Skukuza Models
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Sites: Mopani Models
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Measurement strategy Ground-based – 2-3 transects along sites of ~200m per site, separated by 25m – Hemiphotos, LAI2k every 10-20m, GPS’d and marked with stakes (to survive burn), spectral measurements and scene components Helicopter – Follow (as far as possible), same transects but measure every 50m (ish) – Downward and oblique photography plus spectral measurements
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Measurement strategy Models 2-3 transects of ~200m per site (avoid edge effects) Measurements every 10-20m along transects 30-60 points per site
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Optical fieldwork: structural Tree number, location and structure Tree location (GPS), height (clinometer), DBH (tape), crown size (tape, clinometer) Post burn loss of trees? Crown size DBH
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Optical fieldwork: structural Pre/post burn oblique aerial photography Tree height, % tree cover
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Optical fieldwork: structural Gap fraction and LAI eff Hemiphotos, LAI eff (LAI2000) from same locations within canopy
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Optical fieldwork: radiometric (spectral) Ground-based 2 x ASD FS Pro spectroradiometer (350-2500nm, 1nm band width) Following grid pattern laid out for hemiphotos etc. 1-3m above canopy (low stature) - 0.5-1m IFOV (single material) Above smaller trees (ladder), then…. transects
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Optical fieldwork: radiometric (spectral) Helicopter measurements ASD mounted on 1.5m pole, extended from helicopter 2nd instrument measuring irradiance on the ground Multiple measurements at multiple points in each site, from ~100m I.e. IFOV 20-40m (scene-wide)
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Optical fieldwork: radiometric (spectral) Scene components – Leaf size, shape (photos) and using ASD contact probe – Burned and unburned material, bark, wood etc.
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3D RT models Models Structure from 3D modelling software (OnyxTREE) A large range of parameters, existing models, complex/very flexible Explicit removal of wood, leaf material (post burn)
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3D RT models Wide range of plant shapes and forms including trees, bushes and grasses
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3D RT models Iterative parameterisation of shape, gap fraction, DBH, height, based on field measurements – Forward modelling to compare with field measurements – Inverse to derive canopy parameters (fCOVER, LAIeff) from observations Radiometric (leaf, trunk etc.) info. from ASD measurements iterate
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3D RT models Spruce plantation….etc.
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3D RT models Model development requires field measurements
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