3D radiative transfer modelling of fire impacts on a two-layer savanna system

Disney, Mathias; Lewis, P.; Gómez-Dans, José; Roy, David P.; Wooster, Martin J.; Lajas, Dulce

doi:10.1016/j.rse.2011.03.010

Cited by 57 publications

(25 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We anticipate that realistic geometrically explicit plot-scale models based on TLS data will be used in place of simplified models based on traditional forest measurement for studies that model the canopy radiation regime such as Radiation Transfer Model Intercomparisons, RAMI [93,94]. Geometrically explicit models will allow the development of more realistic canopy scattering models for estimation of canopy properties from remote sensing data, to be used in optical and microwave radiative transfer modelling [95,96]. This prospect has led the European Space Agency and NASA to undertake TLS measurements of tropical forest plots in preparations for their forthcoming spaceborne BIO-MASS SAR [97] and GEDI lidar [98] missions that aim to quantify tropical forest structure and biomass on regional to continental scales.…”

Section: Methods Developmentmentioning

confidence: 99%

Terrestrial Laser Scanning for Plot-Scale Forest Measurement

et al. 2015

View full text Add to dashboard Cite

Plot-scale measurements have been the foundation for forest surveys and reporting for over 200 years. Through recent integration with airborne and satellite remote sensing, manual measurements of vegetation structure at the plot scale are now the basis for landscape, continental and international mapping of our forest resources. The use of terrestrial laser scanning (TLS) for plot-scale measurement was first demonstrated over a decade ago, with the intimation that these instruments could replace manual measurement methods. This has not yet been the case, despite the unparalleled structural information that TLS can capture. For TLS to reach its full potential, these instruments cannot be viewed as a logical progression of existing plot-based measurement. TLS must be viewed as a disruptive technology that requires a rethink of vegetation surveys and their application across a wide range of disciplines. We review the development of TLS as a plotscale measurement tool, including the evolution of both instrument hardware and key data processing methodologies. We highlight two broad data modelling approaches of gap probability and geometrical modelling and the basic theory that underpins these. Finally, we discuss the future prospects for increasing the utilisation of TLS for plot-scale forest assessment and forest monitoring.

show abstract

Section: Methods Developmentmentioning

confidence: 99%

Terrestrial Laser Scanning for Plot-Scale Forest Measurement

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Shea et al (1996) previously described around three quarters of the fuel consumed in these KNP plots as being grasses. Further plot descriptions, example pre-and post-fire aerial photography and matching scene simulations can be seen in Disney et al (2011) related to a subsequent (2008) field campaign.…”

Section: Study Area and Measurement Methodsmentioning

confidence: 99%

Field determination of biomass burning emission ratios and factors via open-path FTIR spectroscopy and fire radiative power assessment: headfire, backfire and residual smouldering combustion in African savannahs

et al. 2011

View full text Add to dashboard Cite

Abstract. Biomass burning emissions factors are vital to quantifying trace gas release from vegetation fires. Here we evaluate emissions factors for a series of savannah fires in Kruger National Park (KNP), South Africa using groundbased open path Fourier transform infrared (FTIR) spectroscopy and an IR source separated by 150-250 m distance. Molecular abundances along the extended open path are retrieved using a spectral forward model coupled to a nonlinear least squares fitting approach. We demonstrate derivation of trace gas column amounts for horizontal paths transecting the width of the advected plume, and find for example that CO mixing ratio changes of ∼0.01 µmol mol −1 [10 ppbv] can be detected across the relatively long optical paths used here. Though FTIR spectroscopy can detect dozens of different chemical species present in vegetation fire smoke, we focus our analysis on five key combustion products released preferentially during the pyrolysis (CH 2 O), flaming (CO 2 ) and smoldering (CO, CH 4 , NH 3 ) processes. We demonstrate that well constrained emissions ratios for these gases to both CO 2 and CO can be derivedCorrespondence to: M. J. Wooster (martin.wooster@kcl.ac.uk) for the backfire, headfire and residual smouldering combustion (RSC) stages of these savannah fires, from which stagespecific emission factors can then be calculated. Headfires and backfires often show similar emission ratios and emission factors, but those of the RSC stage can differ substantially. The timing of each fire stage was identified via airborne optical and thermal IR imagery and ground-observer reports, with the airborne IR imagery also used to derive estimates of fire radiative energy (FRE), allowing the relative amount of fuel burned in each stage to be calculated and "fire averaged" emission ratios and emission factors to be determined. These "fire averaged" metrics are dominated by the headfire contribution, since the FRE data indicate that the vast majority of the fuel is burned in this stage. Our fire averaged emission ratios and factors for CO 2 and CH 4 agree well with those from prior studies conducted in the same area using e.g. airborne plume sampling. We also concur with past suggestions that emission factors for formaldehyde in this environment appear substantially underestimated in widely used databases, but see no evidence to support suggestions by Sinha et al. (2003) of a major overestimation in the emission factor of ammonia in works such as Andreae and Merlet (2001) and Akagi et al. (2011). We also measure somewhat higher CO and NH 3 emission ratios and factors Published by Copernicus Publications on behalf of the European Geosciences Union. 11592 M. J. Wooster et al.: OP-FTIR determination of biomass burning emission ratios than are usually reported for this environment, which is interpreted to result from the OP-FTIR ground-based technique sampling a greater proportion of smoke from smouldering processes than is generally the case with methods such as airborne sampling. Finally, our results sugg...

show abstract

“…The model is generated using an empirical growth model parametrized by species-dependent branching statistics in conjunction with specified external environmental conditions [29]. TLS point clouds were simulated using the Monte Carlo ray-tracing code which has been used for a wide range of applications [28,[30][31][32]. Simulation parameters were the same as in the scanner used in the measurements (see above).…”

Section: Data: Point Cloudsmentioning

confidence: 99%

Fast Automatic Precision Tree Models from Terrestrial Laser Scanner Data

et al. 2013

View full text Add to dashboard Cite

This paper presents a new method for constructing quickly and automatically precision tree models from point clouds of the trunk and branches obtained by terrestrial laser scanning. The input of the method is a point cloud of a single tree scanned from multiple positions. The surface of the visible parts of the tree is robustly reconstructed by making a flexible cylinder model of the tree. The thorough quantitative model records also the topological branching structure. In this paper, every major step of the whole model reconstruction process, from the input to the finished model, is presented in detail. The model is constructed by a local approach in which the point cloud is covered with small sets corresponding to connected surface patches in the tree surface. The neighbor-relations and geometrical properties of these cover sets are used to reconstruct the details of the tree and, step by step, the whole tree. The point cloud and the sets are segmented into branches, after which the branches are modeled as collections of cylinders. From the model, the branching structure and size properties, such as volume and branch size distributions, for the whole tree or some of its parts, can be approximated. The approach is validated using both measured and modeled terrestrial laser scanner data from real trees and detailed 3D models. The results Remote Sens. 2013, 5 492 show that the method allows an easy extraction of various tree attributes from terrestrial or mobile laser scanning point clouds.

show abstract

3D radiative transfer modelling of fire impacts on a two-layer savanna system

Cited by 57 publications

References 67 publications

Terrestrial Laser Scanning for Plot-Scale Forest Measurement

Terrestrial Laser Scanning for Plot-Scale Forest Measurement

Field determination of biomass burning emission ratios and factors via open-path FTIR spectroscopy and fire radiative power assessment: headfire, backfire and residual smouldering combustion in African savannahs

Fast Automatic Precision Tree Models from Terrestrial Laser Scanner Data

Contact Info

Product

Resources

About