A simple normalized difference approach to burnt area mapping using multi-polarisation C-band SAR

dc.contributor.authorEngelbrecht, Jeanineen_ZA
dc.contributor.authorTheron, Andreen_ZA
dc.contributor.authorVhengani, Lufunoen_ZA
dc.contributor.authorKemp, Jacoen_ZA
dc.date.accessioned2018-01-22T12:59:35Z
dc.date.available2018-01-22T12:59:35Z
dc.date.issued2017
dc.descriptionCITATION: Engelbrecht, J., et al. 2017. A simple normalized difference approach to burnt area mapping using multi-polarisation C-band SAR. Remote Sens, 9(8):764, doi:10.3390/rs9080764.
dc.descriptionThe original publication is available at http://www.mdpi.com/2072-4292/9/8/764
dc.description.abstractIn fire-prone ecosystems, periodic fires are vital for ecosystem functioning. Fire managers seek to promote the optimal fire regime by managing fire season and frequency requiring detailed information on the extent and date of previous burns. This paper investigates a Normalised Difference α-Angle (NDαI) approach to burn-scar mapping using C-band data. Polarimetric decompositions are used to derive α-angles from pre-burn and post-burn scenes and NDαI is calculated to identify decreases in vegetation between the scenes. The technique was tested in an area affected by a wildfire in January 2016 in the Western Cape, South Africa. The quad-pol H-A-α decomposition was applied to RADARSAT-2 data and the dual-pol H-α decomposition was applied to Sentinel-1A data. The NDαI results were compared to a burn scar extracted from Sentinel-2A data. High overall accuracies of 97.4% (Kappa = 0.72) and 94.8% (Kappa = 0.57) were obtained for RADARSAT-2 and Sentinel-1A, respectively. However, large omission errors were found and correlated strongly with areas of high local incidence angle for both datasets. The combined use of data from different orbits will likely reduce these errors. Furthermore, commission errors were observed, most notably on Sentinel-1A results. These errors may be due to the inability of the dual-pol H-α decomposition to effectively distinguish between scattering mechanisms. Despite these errors, the results revealed that burnt areas could be extracted and were in good agreement with the results from Sentinel-2A. Therefore, the approach can be considered in areas where persistent cloud cover or smoke prevents the extraction of burnt area information using conventional multispectral approachesen_ZA
dc.description.urihttp://www.mdpi.com/2072-4292/9/8/764
dc.description.versionPublisher's version
dc.format.extent13 pages : illustrations
dc.identifier.citationEngelbrecht, J., et al. 2017. A simple normalized difference approach to burnt area mapping using multi-polarisation C-band SAR. Remote Sens, 9(8):764, doi:10.3390/rs9080764en_ZA
dc.identifier.issn2072-4292 (online)
dc.identifier.otherdoi:10.3390/rs9080764
dc.identifier.urihttp://hdl.handle.net/10019.1/103071
dc.language.isoen_ZAen_ZA
dc.publisherMDPI
dc.rights.holderAuthors retain copyright
dc.subjectBurnt areaen_ZA
dc.subjectSynthetic aperture radar (SAR)en_ZA
dc.subjectPolarimetric decompositionen_ZA
dc.subjectSentinel-1en_ZA
dc.subjectRADARSAT-2en_ZA
dc.titleA simple normalized difference approach to burnt area mapping using multi-polarisation C-band SARen_ZA
dc.typeArticleen_ZA
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