OPERA Land Surface Disturbance Alert from Harmonized Landsat Sentinel-2 product (Version 1)

The OPERA_L3_DIST-ALERT-HLS (or DIST-ALERT) data product is provided in Cloud Optimized GeoTIFF (COG) format, and each layer is distributed as a separate file. There are 19 layers contained within the DIST-ALERT product. The layers for both vegetation and generic disturbance include disturbance status, loss or anomaly, maximum loss anomaly, disturbance confidence layer, date of disturbance, count of observations with loss anomalies, days of ongoing anomalies, and day of last disturbance detection.

Additional layers are vegetation cover percent, historical percent vegetation cover, and data mask. See the Product Specification Document (PSD) for a more detailed description of the individual layers provided in the DIST-ALERT product. The OPERA project is funded by NASA’s Satellite Needs Working Group (SNWG) which provides data products developed to meet the needs of stakeholders from US government agencies.

The OPERA_L3_DIST-ALERT-HLS product contains modified Copernicus Sentinel data (2020-2025). Processing Improvements/Changes

• For DIST-ALERT granules processed prior to July 21, 2026, the GeoTIFF "Input_DIST-ALERT_granule" metadata field lists a single granule. From July 21, 2026 onward, multiple prior granules may be referenced to account for all recent HLS granules as when a granule with an earlier sensing time is made available after a granule with a later sensing time. In this case, the field contains a comma-separated list. This processing update also applies to the "Input_DIST-ALERT_granule" field under the “AdditionalAttributes” section in the cmr.json file.

Known Issues

* Additional usage constraints are provided under Section 5 of the Algorithm Theoretical Basis Document (ATBD).