Evaluation of ALOS PALSAR Imagery for Burned Area Mapping in Greece Using Object-Based Classification

Abstract

Abstract:In this work, the potential of Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) imagery to map burned areas was evaluated in two study areas in Greece. For this purpose, we developed an object-based classification scheme to map the fire-disturbed areas using the PALSAR imagery acquired before and shortly after fire events. The advantage of employing an object-based approach was not only the use of the temporal variation of the backscatter coefficient, but also the incorporation in the classification of topological features, such as neighbor objects, and class related features, such as objects classified as burned. The classification scheme resulted in mapping the burned areas with satisfactory results: 0.71 and 0.82 probabilities of detection for the two study areas. Our investigation revealed that the pre-fire vegetation conditions and fire severity should be taken in consideration when mapping burned areas using PALSAR in Mediterranean regions. Overall, findings suggest that the developed scheme could be applied for rapid burned area assessment, especially to areas where cloud cover and fire smoke inhibit accurate mapping of burned areas when optical data are used.

A Simple Normalized Difference Approach to Burnt Area Mapping Using Multi-Polarisation C-Band SAR

“…Several studies have investigated multispectral data sources for their ability to map burnt areas in various environments [3,10,14,19]. Using a time-series of investigations, these products have been found useful for the compilation of date-of-burn maps to estimate fire season as well as for the estimation of fire recurrence period.…”

“…In general, SAR backscatter was found to be affected by many factors including moisture conditions, surface roughness and biomass [4]. Under different conditions, SAR backscatter was found to exhibit either an increase or decrease associated with burnt conditions depending on the region under investigation, the incidence angle of the sensor and the surface conditions [5,19]. Therefore, the identification of burnt areas using a universal backscatter-based algorithm would be complicated.…”

“…The potential of using SAR for the mapping of burnt areas lies in the sensitivity of SAR backscatter to vegetation structure and biomass. In particular, the removal of leaves and branches of vegetation due to fire would lead to a change in SAR backscatter [19]. Studies on the use of SAR data for burnt area detection generally rely on the analysis of SAR backscatter at various polarisations and its variation between burnt and unburnt areas [1,2,5] using single-pass [1,5] or multi-temporal analysis [3] approaches.…”

COSMO-SkyMed potential to detect and monitor Mediterranean maquis fires and regrowth: a pilot study in Capo Figari, Sardinia, Italy

“…Post-fire assessments have been conducted prevalently using optical data; however some studies also report the use of Synthetic Aperture Radar (SAR) data, or combination of optical and SAR (Bernhard et al 2011, Diaz-Delgado et al 2003, Gimeno & San-Miguel-Ayanz 2004, Lentile et al 2006, Mari et al 2012, Polychronaki et al 2013, Ranson et al 2002, Tanase et al 2010a, 2010b, 2010c, Van Wagtendonk et al 2004. Possibly, the wider use of optical data is related to their broader diffusion in previous decades and their easier processing with respect to SAR, though in recent years both data types are equally available and supported by image processing software.…”

Technique for Identifying Burned Vegetation Area Using Landsat 8 Data

“…The ERS-2 was also used by Ruecker and Siegert (2000) for burned area mapping in East Kalimantan, Indonesia with an accurate estimation of 90%. Another research was also done by Polychronaki et al (2013) using ALOS PALSAR data for burned area mapping with an accuracy up to 82%. Based on the previous studies, SAR data are very potential to be used on burned area mapping, but the continuity of SAR data is still a big problem for long term operational use.…”