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

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

Sites: Satara  Models

Sites: Pretoriuskop  Models

Sites: Skukuza  Models

Sites: Mopani  Models

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

Measurement strategy  Models 2-3 transects of ~200m per site (avoid edge effects) Measurements every 10-20m along transects points per site

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

Optical fieldwork: structural  Pre/post burn oblique aerial photography Tree height, % tree cover

Optical fieldwork: structural  Gap fraction and LAI eff Hemiphotos, LAI eff (LAI2000) from same locations within canopy

Optical fieldwork: radiometric (spectral)  Ground-based 2 x ASD FS Pro spectroradiometer ( nm, 1nm band width) Following grid pattern laid out for hemiphotos etc. 1-3m above canopy (low stature) m IFOV (single material) Above smaller trees (ladder), then…. transects

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)

Optical fieldwork: radiometric (spectral)  Scene components – Leaf size, shape (photos) and  using ASD contact probe – Burned and unburned material, bark, wood etc.

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)

3D RT models Wide range of plant shapes and forms including trees, bushes and grasses

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

3D RT models Spruce plantation….etc.

3D RT models  Model development requires field measurements