South Korean wildfires that occurred in March 2025 left signs of vegetation cover loss near Andong, Uiseong County. This comparison shows the OPERA Land Surface Disturbance layer on the left "A" side and the true-color reflectance image from the MSI instrument aboard the Sentinel-2C satellite on the right "B" side. The Land Surface Disturbance product (DIST) maps disturbances detected when a change to the land surface occurs outside a historical norm. The red and yellow colors show confirmed vegetation disturbance with ≥50% cover loss (red) and <50% vegetation cover loss (yellow) due to the wildfires that ravaged the area. Swipe the center bar back and forth to compare the red and yellow confirmed land surface disturbances with the large swath of brown burned area visible in the true-color reflectance imagery.
DIST-ALERT Imagery Layer
The OPERA Land Surface Disturbance (DIST-ALERT) imagery layer is a Level-3 (L3) product that maps per pixel vegetation disturbance (specifically, vegetation cover loss). Vegetation disturbance is mapped when there is an indicated decrease in vegetation cover within a Harmonized Landsat Sentinel-2 (HLS) pixel. The spatial resolution is 30 m and the displayed layer describes vegetation disturbance status based on confidence, magnitude of loss, and whether it is ongoing.
There are three confidence levels: "first detection" which is loss detected in only the most recent observation, "provisional" upon a second detection of vegetation loss, and "confirmed" once there are sufficient loss detections to reach high confidence of disturbance. These are reported for both disturbances with <50% vegetation cover loss and those with ≥50% loss, whether diffuse across an entire pixel or just a portion of it. These labels persist as long as the anomalies continue to be detected. Once a location no longer has low vegetation cover, confirmed alerts are labeled as "finished" and the others are reset to no disturbance. This status is iteratively updated with each subsequent granule.
The input dataset for generating each product is the Harmonized Landsat Sentinel-2 (HLS) dataset. The OPERA Land Surface Disturbance (L3) imagery layer is available through the Observational Products for End-Users from Remote Sensing Analysis (OPERA) project.
Learn more about OPERA Land Surface Disturbance in Worldview's Land Surface Disturbance Tour Story.
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Referenced Datasets
OPERA Land Surface Disturbance Alert from Harmonized Landsat Sentinel-2 product (Version 1)
HLS Sentinel-2 Multi-spectral Instrument Surface Reflectance Daily Global 30m v2.0