January 2025 Southern California Wildfires Burn Severity Sentinel2

Overview

Scripts and data for analyzing burn severity of the January 2025 Southern California wildfires using Sentinel-2 satellite imagery. This project explores the use of the Differenced Normalized Burn Ratio (dNBR) and Relativized Burn Ratio (RBR) to classify burn severity, leveraging publicly available satellite data and tools like the Copernicus EO Browser for processing and visualization.

Data

This repository provides essential datasets for analyzing burn severity in the Southern California wildfires of January 2025. The data components are organized as follows:

• Burn Severity Map: The output image generated by running the JavaScript script in the Copernicus EO Browser. This map classifies burn severity across the region of interest based on pre- and post-fire Sentinel-2 imagery. It includes varying levels of burn severity, from unburnt to high severity, and is stored in the /assets/ directory. The burn severity classification is derived using the Normalized Burn Ratio (NBR) and Relativized Burn Ratio (RBR).

• Wildfire Event Names: A list of wildfire events analyzed in this study, each corresponding to a specific fire event within the Southern California region during the January 2025 fire season. This dataset, provided in the data/wildfire_area_names.json file, includes the names of the fires and is used for the subsequent generation of the interactive map in HTML. These names are referenced to label specific areas on the map, allowing users to explore the burn severity by wildfire event.

• Geospatial Region Bounding Box: A geographic boundary that defines the area of study for the burn severity analysis, corresponding to the spatial extent of the Sentinel-2 imagery used. This bounding box is represented in the data/region_bounding_box.json file in GeoJSON format and ensures that the output burn severity maps respect the same spatial resolution and coverage. The coordinates within this bounding box align with the imagery tiles and frame the region affected by the wildfires.

These datasets serve as foundational inputs for the analysis. They are derived from publicly accessible Sentinel-2 satellite data and ensure reproducibility of the burn severity classification process. They also provide necessary context for the results.

The data sources include:

• Sentinel-2 Satellite Imagery: Imagery from the Copernicus Sentinel-2 mission, accessed via the Copernicus Data Space Ecosystem.
• Geospatial Coordinates: The region-specific bounding box data sourced from geospatial metadata and the analysis of fire-affected areas.

These datasets facilitate reproducible analysis and provide a foundation for further research into wildfire impact, remote sensing methods, and environmental monitoring.

Data Sources

• Sentinel-2 Satellite Imagery:
  • Provided by the European Union's Copernicus Programme.
  • Accessed via the Copernicus Data Space Ecosystem.
  • Contains modified Copernicus Sentinel data 2025, processed by Edoardo Tosin.
• Geospatial Coordinates: Derived from geospatial metadata for wildfire impact analysis.

Methodology

Burn Severity Classification

The analysis compares pre-fire and post-fire Sentinel-2 imagery to calculate burn severity.

• Input Bands: Near-Infrared (B08) and Short-Wave Infrared (B12) from Sentinel-2.
• Masking: Irrelevant pixels (e.g., water, clouds) are excluded using the Sentinel-2 Scene Classification Layer (SCL).
• Classification: Burn severity is categorized based on RBR values:
  • Unburnt
  • Low severity
  • Moderate severity
  • Moderate-high severity
  • High severity

Interactive Map

This repository includes an interactive HTML burn severity map. The map overlays results onto OpenStreetMap, allowing to explore burn severity interactively.

How to Use

1. Clone or download this repository to your local machine.
2. Open the file index.html in your web browser.
3. The burn severity map will be displayed on top of an OpenStreetMap layer.
4. You can zoom, pan, and click on areas to view data about the burn severity at different points.

Data Generation and Processing Guide

The scripts provided enable independent reproduction of burn severity maps using the Copernicus EO Browser.

Steps

1. Access the Copernicus EO Browser:

   • Visit Copernicus EO Browser.

2. Set the Area of Interest:

   • Use the Create an area of interest feature to define the study area (coordinates in data/region_bounding_box.json).
   • Alternatively, manually select the region on the interactive map.

3. Select Time Range:

   • Specify pre- and post-fire dates using the Time Range tool.

4. Load the Custom Script:

   • Navigate to Layers > Custom > Custom script.
   • Choose a method to load the script:
     • Option 1: Copy the script from the scripts directory and paste it into the browser's scripting interface.
     • Option 2: Use the Load script from URL feature to link to the script.

5. Run the Script:

   • Execute the script to generate a semi-transparent burn severity map.

6. Download Results:

   • Save the processed map image (Copernicus account required).
   • Reference preprocessed maps stored in the /assets/ directory.

License

• Scripts are licensed under the MIT License.
• Images and analysis content are licensed under the Creative Commons Attribution 4.0 International License.