Evaluation of Sentinel 1 imagery for burned area detection in southern Siberia in spring and summer 2015

Abstract

The paper examines the possibility of burned area detection by Sentinel 1 radar images in Zabaikalsky Kraj in April and Buryatia in August 2015. Burned areas were found due to environmental changes in the areas of fire burning. Seasonal variations of backscatter coefficient and texture features in burned areas were shown in comparison to areas not exposed to fire. Burned area can be detected by joint analysis of changes in backscatter coefficient and Haralick's 'contrast' texture feature. It was shown that the RoM method (ratio of means) was useful in identifying areas after fire, while uncontrolled classification, dual polarization, and texture segmentation could not unambiguously interpret the classification results. For the spring period (April) in Zabaikalsky Kraj, an increase of the backscattering coefficient to 4-5 dB for VV and VH polarizations as well as 'contrast' rise by 2 ÷ 2.7 times (VV polarization) were established compared to the period before the fires. For the summer period (August) in Buryatia, a decrease of the backscattering coefficient to 0.1-0.8 dB and 'contrast' fall by more than 2 times were obtained. None of the considered methods could locate burned areas from multi-temporal radar images of a mountainous area, when taiga burnt on very steep slopes. Satellite imagery of Kosmosnimki - Fires operational monitoring system served as additional information.