Forest Fire Mapping Using Multi-Source Remote Sensing Data: A Case Study in Chongqing

Abstract

Forest fires are one of the most severe natural disasters facing global ecosystems, as they have a significant impact on ecological security and social development. As remote sensing technology has developed, burned areas can now be quickly extracted to support fire monitoring and post-disaster recovery. This study focused on monitoring forest fires that occurred in Chongqing, China, in August 2022. The burned area was identified using various satellite images, including Sentinel-2, Landsat8, Environmental Mitigation II A (HJ2A), and Gaofen-6 (GF-6). The burned area was extracted using visual interpretation, differenced Normalized Difference Vegetation Index (dNDVI), and differenced Normalized Burnup Ratio (dNBR). The results showed that: (1) The results of the three monitoring methods were very consistent, with a coefficient of determination R2 > 0.96. (2) A threshold method based on the dNBR-extracted burned area was used to analyze fire severity, with moderate-severity fires making up the majority (58.05%) of the fires. (3) Different topographic factors had some influence on the severity of the forest fires. High elevation, steep slopes and the northwestern aspect had the largest percentage of burned area.

A Land Cover Change Detection Approach to Assess the Effectiveness of Conservation Projects: A Study Case on the EU-Funded LIFE Projects in São Miguel Island, Azores (2002–2021)

“…(2) extracting the red, green, near-infrared (NIR), and SWIR 2 bands of the imagery and calculating the NDVI; (3) calculating the Rao's Q classic [15] using the NDVI; (4) calculating Rao's Q multidimensional (MD 1, MD 2, and MD 3); ( 5) calculating the square root of the post-image minus the pre-image for each project duration; (6) calculating the threshold; and (7) validation of the results through statistical analysis for each LIFE project, complemented by information from reports and historical high-resolution images obtained from satellites (Figure 3).…”

“…The analysis of LULCCs is fundamental for comprehensively understanding and addressing local, regional, and global issues. These encompass a range of phenomena, including alterations in rainfall patterns resulting in droughts [8] and flooding [9], occurrences of landslides [10], coastal erosion [11], the rapid expansion of urban areas [12], intensification of agriculture activity and livestock grazing [13], spreading of invasive alien species [14], and wildfires [15,16], among others.…”