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

The Observational Products for End-Users from Remote Sensing Analysis (OPERA) Land Surface Disturbance Annual from Harmonized Landsat Sentinel-2 (HLS) product Version 1 summarizes the DIST-ALERT data product into an annual vegetation disturbance data product. Vegetation disturbance is mapped when there is an indicated decrease in vegetation cover within an HLS Version 2 pixel. The product also provides auxiliary generic disturbance information as determined from the variations of the reflectance through the DIST-ALERT scenes to provide information about more general disturbance trends. The DIST-ANN product tracks changes at the annual scale, aggregating changes identified in the DIST-ALERT product. Only confirmed disturbances from the associated year are reported together with the date of initial disturbance. As confirmed disturbances are determined using subsequent cloud-free observations to determine if the loss detections persist, the required number of HLS scenes depends on visibility of the target. Due to this dependency, summarizing the DIST-ALERT in the DIST-ANN product will have some latency contingent on the algorithmic calibration and is detailed in the Algorithm Theoretical Basis Document (ATBD). The OPERA_L3_DIST-ANN-HLS (or DIST-ANN) data product is provided in Cloud Optimized GeoTIFF (COG) format, and each layer is distributed as a separate COG. There are 21 layers contained within the DIST-ANN product: vegetation disturbance status, historical vegetation cover indicator, maximum vegetation cover indicator, maximum vegetation anomaly value, vegetation disturbance confidence layer, date of initial vegetation disturbance, number of detected vegetation loss anomalies, vegetation disturbance duration, date of last observation assessed for vegetation disturbance, and several generic disturbance layers. Each product layer is gridded to the same resolution and tiling system as HLS V2: 30 meter (m) and Military Grid Reference System (MGRS). See the Product Specification Document (PSD) for a more detailed description of the individual layers provided in the DIST-ANN 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-ANN-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).

Date of Images: 10/11/2024, 10/12/2024 Summary: The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at NASA's Jet Propulsion Laboratory and California Institute of Technology derived the disturbance maps using the OPERA Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) products. The results posted here are preliminary and unvalidated results, primarily intended to aid the field response and people who want to have a rough first look at the surface disturbance extent. The ARIA-share website has always focused on posting preliminary results as fast as possible for disaster response. OPERA DIST-ALERT-HLS The Disturbance product (DIST) maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the vegetation disturbance status (VEG-DIST-STATUS) and the maximum vegetation anomaly value (VEG-ANOM-MAX) layers. Images are provided from October 2, 2024. Each image consists of multiple MGRS tiles that were merged together for a composite image saved as a GeoTIFF file. VEG-ANOM-MAX Difference between historical and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >20% vegetation cover loss). The sum of the historical percent vegetation and the anomaly value will be the vegetation cover estimate for the current year. GEN-ANOM-MAX Maximum spectral distance between a current year HLS scene reflectance and the composite reflectance of previous calendar years. Generic disturbance, as determined from the variations of the reflectance through the HLS scenes, is intended to delineate generic changes outside of the vegetation cover loss theme. The DIST-ALERT HLS products have these flags: For VEG-ANOM-MAX layers, 255 represents No Data and is based on the Fmask layer of the source HLS granule. For the GEN-ANOM-MAX layer, -1 represents "No Data" and is based on the Fmask layer of the source HLS granule. Suggested Use: VEG-ANOM-MAX 0 (White) - 100 (Red): Maximum loss of percent vegetation 255: No data GEN-ANOM-MAX 0 (White) - Variable (Blue): Maximum spectral distance compared to composite reflectance of previous calendar years -1: No Data Satellite/Sensor: MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/B satellites and Operational Land Imager 2 (OLI-2) on NASA's Landsat 9 satellite. Resolution: 30 meters Credits: NASA JPL-Caltech ARIA/OPERA Team The product contains modified Copernicus Sentinel data (2024) and is produced as part of the OPERA project, which is funded by NASA to address remote sensing needs identified by the Satellite Needs Working Group. Managed by NASA's Jet Propulsion Laboratory, OPERA funds and manages the DIST-ALERT-HLS product developed and produced by the Global Land Analysis and Discovery (GLAD) laboratory at the University of Maryland. Additional Information: The OPERA DIST-HLS products have been in production since January 2022, are freely distributed to the public via NASA's Land Processes Distributed Active Archive Center (LP DAAC), and can be downloaded through NASA's Earthdata search. For more information about the Surface Disturbance product suite, please refer to the DIST Product page: https://www.jpl.nasa.gov/go/opera/products/dist-product-suite/ For more information about the Caltech-JPL ARIA project, visit https://aria.jpl.nasa.gov For more information about the JPL OPERA project, visit https://www.jpl.nasa.gov/go/opera/ Data Download: https://aria-share.jpl.nasa.gov/20241010-Hurricane_Milton/DIST/ Esri REST Endpoint:

This dataset is a derivative of the OPERA’s DIST-ALERT product (OPERA Land Surface Disturbance Alert from Harmonized Landsat Sentinel-2 product), which is derived through a time-series analysis of harmonized data from the NASA/USGS Landsat and ESA Sentinel-2 satellites (known as the HLS dataset). The product identifies and continuously monitors vegetation cover change in 30-m pixels across the globe. It can be accessed through the LPDAAC website here: https://search.earthdata.nasa.gov/search?q=C2746980408-LPCLOUD, and on Google Earth Engine (GEE) with asset ID: projects/glad/HLSDIST/current The DIST-ALERT on GNW is a derivative of this, and additional data layers not used in the GNW product are available through the LPDAAC and GEE such as initial vegetation fraction, and disturbance duration. Specifically, three layers are used to create the GNW DIST-ALERT. The VEG-DIST-DATE provides the date of the alert, the VEG-DIST-COUNT is used to determine the confidence (2-3 consecutive observations for low confidence and 4+ observations for high confidence) and VEG-ANOM-MAX is used as a threshold for determining loss (>30%). While the version on the LPDAAC is updated every 2-4 days, the data is updated weekly on GNW. The product detects notable reductions in vegetation cover (measured as “vegetation fraction” or the percent of the ground that is covered by vegetation) for every pixel every time the new satellite data is acquired and the ground is not obscured by clouds or snow. The current vegetation fraction estimate is compared to the minimum fraction for the same time period (within 15 days before and after) in the previous 3 years, and if there is a reduction, then the system identifies an alert in that pixel. Anomalies of at least a 10% reduction from the minimum become alerts in the original product, and on GNW, a higher threshold of 30% is used, to reduce noise, and false alerts in the dataset. Because the product compares each pixel to the minimum for the same time period in previous years, it takes into account regular seasonal variation in vegetation cover. As the product is global and detects vegetation anomalies, much of the data may not be applicable to GNW users monitoring forests. Therefore, we mask the alerts with UMD’s tree cover map, allowing users to view only alerts within 30% canopy cover. Monitors global vegetation disturbance in near-real-time using harmonized Landsat-Sentinel-2 (HLS) imagery

Date of Images: 10/11/2024, 10/12/2024 Summary: The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at NASA's Jet Propulsion Laboratory and California Institute of Technology derived the disturbance maps using the OPERA Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) products. The results posted here are preliminary and unvalidated results, primarily intended to aid the field response and people who want to have a rough first look at the surface disturbance extent. The ARIA-share website has always focused on posting preliminary results as fast as possible for disaster response. OPERA DIST-ALERT-HLS The Disturbance product (DIST) maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the vegetation disturbance status (VEG-DIST-STATUS) and the maximum vegetation anomaly value (VEG-ANOM-MAX) layers. Images are provided from October 2, 2024. Each image consists of multiple MGRS tiles that were merged together for a composite image saved as a GeoTIFF file. VEG-ANOM-MAX Difference between historical and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >20% vegetation cover loss). The sum of the historical percent vegetation and the anomaly value will be the vegetation cover estimate for the current year. GEN-ANOM-MAX Maximum spectral distance between a current year HLS scene reflectance and the composite reflectance of previous calendar years. Generic disturbance, as determined from the variations of the reflectance through the HLS scenes, is intended to delineate generic changes outside of the vegetation cover loss theme. The DIST-ALERT HLS products have these flags: For VEG-ANOM-MAX layers, 255 represents No Data and is based on the Fmask layer of the source HLS granule. For the GEN-ANOM-MAX layer, -1 represents "No Data" and is based on the Fmask layer of the source HLS granule. Suggested Use: VEG-ANOM-MAX 0 (White) - 100 (Red): Maximum loss of percent vegetation 255: No data GEN-ANOM-MAX 0 (White) - Variable (Blue): Maximum spectral distance compared to composite reflectance of previous calendar years -1: No Data Satellite/Sensor: MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/B satellites and Operational Land Imager 2 (OLI-2) on NASA's Landsat 9 satellite. Resolution: 30 meters Credits: NASA JPL-Caltech ARIA/OPERA Team The product contains modified Copernicus Sentinel data (2024) and is produced as part of the OPERA project, which is funded by NASA to address remote sensing needs identified by the Satellite Needs Working Group. Managed by NASA's Jet Propulsion Laboratory, OPERA funds and manages the DIST-ALERT-HLS product developed and produced by the Global Land Analysis and Discovery (GLAD) laboratory at the University of Maryland. Additional Information: The OPERA DIST-HLS products have been in production since January 2022, are freely distributed to the public via NASA's Land Processes Distributed Active Archive Center (LP DAAC), and can be downloaded through NASA's Earthdata search. For more information about the Surface Disturbance product suite, please refer to the DIST Product page: https://www.jpl.nasa.gov/go/opera/products/dist-product-suite/ For more information about the Caltech-JPL ARIA project, visit https://aria.jpl.nasa.gov For more information about the JPL OPERA project, visit https://www.jpl.nasa.gov/go/opera/ Data Download: https://aria-share.jpl.nasa.gov/20241010-Hurricane_Milton/DIST/ Service URL: https://gis.earthdata.nasa.gov/portal/home/item.html?id=dfe2b9e3f03b468a89286e06eb60e4be WMS: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_202410_HURRICANE_MILTON/2428_opera_dist_hls/ImageServer/WMSServer

Researchers working with the Global Land Analysis & Discovery (GLAD) at University of Maryland, College Park, Maryland and Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at NASA's Jet Propulsion Laboratory, Pasadena, California, created maps of surface disturbance due to ongoing wildfires in Los Angeles County in January 2025 using the OPERA Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) products. The results posted here are preliminary results, primarily intended to aid the field response and people who wanted to have a rough first look at the area impacted by wildfire. The ARIA-share website has always focused on posting preliminary results as fast as possible for urgent response. All information is provisional for use under emergency response guidelines. These data are provided with absolutely no warranty of any kind. Use at your own risk. OPERA DIST-ALERT-HLS The Disturbance product (DIST) maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the (1) maximum vegetation anomaly value (VEG-ANOM-MAX) layer and (2) vegetation disturbance status (VEG-DIST-STATUS). All provided layers have been filtered to include only disturbance detected following the start of the Greater Los Angeles wildfires (starting Jan. 7, 2025). Images are provided from January 12 and January 14, 2025. The images are provided as GeoTIFF files. VEG-ANOM-MAX: Difference between historical and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >=20% vegetation cover loss). The sum of the historical percent vegetation and the anomaly value will be the vegetation cover estimate for the current year. VEG-DIST-STATUS: Indication of vegetation cover loss (vegetation disturbance). The status label is based on the maximum anomaly value, confidence level, and whether it is ongoing or finished. "First" means the pixel has had an anomaly detection but no subsequent observations whether anomalous or not. ''Provisional'' means there have been two consecutive disturbance detections but not yet with high confidence. ''Confirmed'' means that vegetation disturbance is detected with high confidence. The label ''finished'' is applied to confirmed disturbances that have had two consecutive no-anomaly observations or one 15 days or more after the last anomaly detection. If a new disturbance is detected, it will overwrite those in a ''finished'' state. These labels are reported for both above and below the 50% disturbance threshold based on the maximum anomaly value. Satellite/Sensor: MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/B satellites and Operational Land Imager 2 (OLI-2) on NASA's Landsat 8/9 satellite. Resolution: 30 meters The DIST-ALERT-HLS products included here have these flags: 255 represents ''No Data'' and is based on the Fmask layer of the source HLS granule. OPERA DIST-ALERT-HLS data availability: The post-processed products are available to download at https://aria-share.jpl.nasa.gov/20250113-GreaterLosAngeles_Fires/DIST-HLS/ The OPERA DIST-HLS products have been in production since January 2022, are freely distributed to the public via NASA's Land Processes Distributed Active Archive Center (LP DAAC), and can be downloaded through NASA's Earthdata search. For more information about the Surface Disturbance product suite, please refer to the DIST Product page: https://www.jpl.nasa.gov/go/opera/products/dist-product-suite/ For more information about the GLAD project, visit https://glad.umd.edu/ For more information about the Caltech-JPL ARIA project, visit https://aria.jpl.nasa.gov For more information about the JPL OPERA project, visit https://www.jpl.nasa.gov/go/opera/ Suggested Use for DIST-HLS: VEG-DIST-STATUS: Layer values: 0: No disturbance (suggested color: #121212) 1: first 2: provisional 3: confirmed 4: first >=50% (suggested color: #008888) 5: provisional >=50% (suggested color: #e48727) 6: confirmed >=50% (suggested color: #e01b07) 7: confirmed 8: confirmed >=50%, finished (suggested color: #dddddd) 255: No data (suggested color: transparent) VEG-ANOM-MAX: Layer values: 0-100: Maximum loss of percent vegetation (suggested color: white to red gradient) 255: No data (suggested color: transparent) Product POCs: Alexander L. Handwerger (alexander.handwerger@jpl.nasa.gov) Zhen Song (zhensong@umd.edu) Matt Hansen (mhansen@umd.edu) Steven Chan (steventsz.k.chan@jpl.nasa.gov) David Bekaert (david.bekaert@jpl.nasa.gov) Credits: The product contains modified Copernicus Sentinel data (2024) and is produced as part of the OPERA project, which is funded by NASA to address remote sensing needs identified by the Satellite Needs Working Group. Managed by NASA's Jet Propulsion Laboratory, OPERA funds and manages the DIST-ALERT-HLS product developed and produced by the Global Land Analysis and Discovery (GLAD) laboratory at the University of Maryland. NASA JPL-Caltech-UMD ARIA/OPERA Team ================== Files: OPERA-DIST-ALERT-HLS-VEG-ANOM-MAX_01-14-2025.tif: January 14, 2025 showing the maximum vegetation anomaly. OPERA-DIST-ALERT-HLS-VEG-DIST-STATUS_01-14-2025.tif: January 14, 2025 showing the status anomaly. OPERA-DIST-ALERT-HLS-VEG-ANOM-MAX_20250112.tif: January 12, 2025 showing the maximum vegetation anomaly. OPERA-DIST-ALERT-HLS-VEG-DIST-STATUS_20250112.tif: January 12, 2025 showing the status anomaly. Last Update 14 January 2025 Service URL: https://gis.earthdata.nasa.gov/portal/home/item.html?id=3a64b84ac45040a4bc78adf5872ad7de WMS Endpoint: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_202501_FIRE_CA/2501_opera_dist_hls/ImageServer/WMSServer Data Download: https://aria-share.jpl.nasa.gov/20250113-GreaterLosAngeles_Fires/DIST-HLS/

Dates of Images: 20260724T1849, 20260725T1843, 20260727T1901 (GMT) (YYYYMMDDTHHMM) Summary: The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at the Jet Propulsion Laboratory, California Institute of Technology produced maximum vegetation anomaly loss and disturbance status, using the OPERA Surface Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) dataset. The dataset provided includes two product types: Vegetation Disturbance Status maps on individual dates Maximum Vegetation Anomaly loss maps on individual dates Dates and Input Data: Images: June 24, July 25, and July 27, 2026 Products are generated from OPERA DIST-ALERT-HLS satellite imagery and mosaicked across tiles to provide continuous coverage. Product Description: Surface Disturbance, specifically vegetation loss, is identified from optical satellite imagery and mapped at 30 m spatial resolution. The Vegetation Disturbance Status layer indicates the confidence that vegetation loss has occurred, and whether the disturbance is still ongoing or has ended. The Max Vegetation Anomaly loss shows how much vegetation has been lost at each location, based on the largest change observed during the time period. As the number of post-event images increase, the confidence in the detections increases. Note we applied a temporal filter to these products. The temporal filter was used to remove any surface disturbance that occurred prior to the onset of the wildfires. Caveats and Limitations: This product detects vegetation loss due to any reason. Importantly, not all detected changes are due to wildfire on July 23, 2026. These results are intended to support rapid emergency response. All information is provisional for use under emergency response guidelines. These data are provided with absolutely no warranty of any kind. Use at your own risk. Suggested Use: The OPERA DIST-ALERT-HLS maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the (1) maximum vegetation anomaly value (VEG-ANOM-MAX) layer and (2) vegetation disturbance status (VEG-DIST-STATUS). All provided layers have been filtered to include only disturbance detected following the start of the fires. VEG-ANOM-MAX: Difference between 3 year historical baseline and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >=20% vegetation cover loss). Layer Values: 0-100: Maximum loss of percent vegetation (suggested color: white to red gradient) 255: No data (suggested color: transparent) File names: OPERA_L3_DIST-ALERT-HLS_V1_VEG-ANOM-MAX_20260724T1849_mosaic.tif, OPERA_L3_DIST-ALERT-HLS_V1_VEG-ANOM-MAX_20260725T1843_mosaic.tif, OPERA_L3_DIST-ALERT-HLS_V1_VEG-ANOM-MAX_20260727T1901_mosaic.tif VEG-DIST-STATUS: Indication of vegetation cover loss (vegetation disturbance). The status label is based on the maximum anomaly value, confidence level, and whether it is ongoing or finished. ''First'' means the pixel has had an anomaly detection but no subsequent observations whether anomalous or not. ''Provisional'' means there have been two consecutive disturbance detections but not yet with high confidence. ''Confirmed'' means that vegetation disturbance is detected with high confidence. The label ''finished'' is applied to confirmed disturbances that have had two consecutive no-anomaly observations or one 15 days or more after the last anomaly detection. If a new disturbance is detected, it will overwrite those in a ''finished'' state. These labels are reported for both above and below the 50% disturbance threshold based on the maximum anomaly value. Layer Values: 0: No disturbance (suggested color: #121212) 1: first 2: provisional 3: confirmed 4: first >=50% (suggested color: #008888) 5: provisional >=50% (suggested color: #e48727) 6: confirmed >=50% (suggested color: #e01b07) 7: confirmed 8: confirmed >=50%, finished (suggested color: #dddddd) 255: No data (suggested color: transparent) File names: OPERA_L3_DIST-ALERT-HLS_V1_VEG-DIST-STATUS_20260724T1849_mosaic.tif, OPERA_L3_DIST-ALERT-HLS_V1_VEG-DIST-STATUS_20260725T1843_mosaic.tif, OPERA_L3_DIST-ALERT-HLS_V1_VEG-DIST-STATUS_20260727T1901_mosaic.tif Satellite/Sensor/Resolution: Satellite/Sensor: Harmonized Landsat Sentinel-2 (HLS) derived from MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/2B/2C satellites and Operational Land Imager 2 (OLI-2) on NASA/USGS Landsat 8/9 satellites. Spatial Resolution: 30 meters Temporal Resolution: Sub-weekly Credits: The product contains modified Copernicus Sentinel-2 and NASA Landsat 8/9 data, processed by the European Space Agency and NASA. Data were analyzed by the NASA-JPL/Caltech ARIA/OPERA team. The DIST products are produced as part of the OPERA project, which is funded by NASA to address remote sensing needs identified by the Satellite Needs Working Group, and managed by NASA's Jet Propulsion Laboratory. The DIST-ALERT-HLS product was developed and produced by the OPERA Global Land Analysis and Discovery (GLAD) laboratory at the University of Maryland. NASA JPL-Caltech-UMD ARIA/OPERA Team Product POCs: Cole Speed (cole.speed@jpl.nasa.gov) Mary Grace Bato (bato@jpl.nasa.gov) Alexander Handwerger (alexander.handwerger@jpl.nasa.gov ) Esri REST Endpoint: See URL to the right. WMS Endpoint: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_202607_FIRE_OR/202618_opera_dist_vegDistStatus/ImageServer/WMSServer Data Download: https://aria-share.jpl.nasa.gov/20260723_Oregon_Fires/