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Description

The Observational Products for End-Users from Remote Sensing Analysis (OPERA) Land Surface Disturbance Alert from Harmonized Landsat Sentinel-2 (HLS) product Version 1 maps vegetation disturbance alerts that are derived from data collected by Landsat 8 and Landsat 9 Operational Land Imager (OLI) and Sentinel-2A, Sentinel-2B, and Sentinel-2C Multi-Spectral Instrument (MSI). A vegetation disturbance alert is detected at 30 meter (m) spatial resolution when there is an indicated decrease in vegetation cover within an HLS pixel. The Level-3 data product also provides additional information about more general disturbance trends and auxiliary generic disturbance information as determined from the variations of the reflectance through the HLS scenes. HLS data represent the highest temporal frequency data available at medium spatial resolution. The combined observations will provide greater sensitivity to land changes, whether of large magnitude/short duration or small magnitude/long duration.

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_L3_DIST-ALERT-HLS product contains modified Copernicus Sentinel data (2020-2025).

Known Issues

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

Version Description

Version 1

Product Summary

Platforms
Sentinel-2A,
Sentinel-2B,
Sentinel-2C,
LANDSAT-8,
LANDSAT-9
Instruments
Sentinel-2 MSI,
OLI
Spatial Extent
N: 90 S: -90 E: 180 W: -180
Spatial Resolution
30 Meters x 30 Meters
Geographic Region
GLOBAL LAND
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2022-01-01 to Present
Temporal Resolution
1 Day
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC)
Global Land Disturbance Mapping for JPL OPERA (Observational Products for End-Users from Remote Sensing Analysis), University of Maryland (UMD/GLAD)
Concept ID
C2746980408-LPCLOUD
Data State
ACTIVE
Processing Level
3
Published
Science Keywords
Land Use/Land Cover,
MECHANICAL DISTURBANCE,
DISTURBANCE

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Hansen, M. (2024). OPERA Land Surface Disturbance Alert from Harmonized Landsat Sentinel-2 product (Version 1) [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/SNWG/OPERA_L3_DIST-ALERT-HLS_V1.001 Date Accessed: 2025-10-28

Documents

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Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
DATA-MASK Mask of pixels the algorithms are applied to in the current HLS scene N/A uint8 N/A N/A to 2 N/A
GEN-ANOM Current generic disturbance anomaly value N/A int16 -1 -1 N/A
GEN-ANOM-MAX Generic disturbance maximum anomaly value N/A int16 -1 -1 N/A
GEN-DIST-CONF Generic Disturbance Confidence Layer N/A int16 -1 -1 N/A
GEN-DIST-COUNT Number of detected spectral anomalies N/A uint8 255 255 to 254 N/A
GEN-DIST-DATE Date of initial generic disturbance Day int16 N/A N/A N/A
GEN-DIST-DUR Generic disturbance duration Day int16 -1 -1 to 366 N/A
GEN-DIST-STATUS Generic disturbance status Class Flag uint8 255 255 to 8 N/A
GEN-LAST-DATE Date of last observation assessed for generic disturbance Day int16 -1 -1 N/A
VEG-ANOM Current vegetation anomaly value Percent uint8 255 255 to 100 N/A
VEG-ANOM-MAX Max vegetation anomaly value Percent uint8 255 255 to 100 N/A
VEG-DIST-CONF Vegetation Disturbance Confidence Layer N/A int16 -1 -1 N/A
VEG-DIST-COUNT Number of detected vegetation loss anomalies N/A uint8 255 255 to 254 N/A
VEG-DIST-DATE Date of initial vegetation disturbance Day int16 -1 -1 N/A
VEG-DIST-DUR Vegetation disturbance duration Day int16 N/A N/A to 366 N/A
VEG-DIST-STATUS Vegetation disturbance status Class Flag uint8 255 255 to 8 N/A
VEG-HIST Historical vegetation cover indicator Percent uint8 255 255 to 200 N/A
VEG-IND Current vegetation cover indicator Percent uint8 255 255 to 100 N/A
VEG-LAST-DATE Date of last observation assessed for vegetation disturbance Day int16 -1 -1 N/A
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