ECOSTRESS Tiled Ancillary NDVI and Albedo L2 Global 70 m V003

The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) mission measures the temperature of plants to better understand how much water plants need and how they respond to stress. ECOSTRESS is attached to the International Space Station (ISS) and collects data globally between 52° N and 52° S latitudes.

The ECOSTRESS Tiled NDVI and Albedo Instantaneous Level 2 Global 70 m (ECO_L2T_STARS) Version 3 data product provides Normalized Difference Vegetation Index (NDVI) and broadband shortwave albedo aligned with each daytime ECOSTRESS overpass. ECO_L2T_STARS is an ancillary data product derived from Visible Infrared Imaging Radiometer Suite ([VIIRS]( https://www.earthdata.nasa.gov/data/instruments/viirs)) and Harmonized Landsat Sentinel-2 ([HLS]( https://www.earthdata.nasa.gov/data/projects/hls)) Version 2 data sources with application to the ECOSTRESS mission. This data product fuses fine resolution inputs from HLS surface reflectance products and moderate resolution inputs from the daily NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS surface reflectance ([VNP09GA]( https://doi.org/10.5067/VIIRS/VNP09GA.002)) product. The data fusion is performed using a variant of the Spatial Timeseries for Automated high-Resolution multi-Sensor data fusion (STARS) algorithm to create tiles matching the ECOSTRESS standard resolution of 70 meters (m). STARS is a Bayesian timeseries methodology that provides streaming data fusion and uncertainty quantification through efficient Kalman filtering. Refer to Section 3 of the Algorithm Theoretical Basis Document (ATBD) for further details of the Bidirectional Reflectance Distribution Function (BRDF) implementation and albedo calculations.

The ECO_L2T_STARS Version 3 data product is provided in Cloud Optimized GeoTIFF (COG) format using a modified version of the Military Grid Reference System ([MGRS]( https://hls.gsfc.nasa.gov/products-description/tiling-system/)), which divides Universal Transverse Mercator (UTM) zones into square tiles that are 109.8 km by 109.8 km with a 70 m spatial resolution. Each variable is distributed as a separate COG. This product contains 10 variables including Normalized Difference Vegetation Index estimates, Broadband shortwave albedo estimates, Uncertainty, and Bias Correction. The ECO_L2T_STARS ancillary NDVI and albedo product is only generated for corresponding daytime ECOSTRESS Tiled Land Surface Temperature and Emissivity Instantaneous L2 Global 70 m ([ECO_L2T_LSTE]( https://doi.org/10.5067/ECOSTRESS/ECO_L2T_LSTE.003)) Version 3 tiles.

Known Issues

* Solar Array Obstruction: Some ECOSTRESS scenes may be affected by solar array obstructions from the ISS, potentially impacting data quality in obstructed pixels. The 'FieldOfViewObstruction' metadata field is reliably populated and accurate for all products generated on or after October 2024, following fixes to the PGE docker configuration and updates to the L1A_RAW_PIX software. Prior to October 2024, the field was not reliably populated; a separate [list of confirmed affected scenes]( https://lpdaac.usgs.gov/documents/2249/obst_all_sort.txt) was maintained and is recommended for verifying historical data.
* Historical acquisition gaps and anomalies (2018–2023): Irrecoverable data loss occurred due to Mass Storage Unit (MSU) failures, resulting in permanent gaps in the observational record where no ECOSTRESS data was acquired. Other early issues, including band 4 striping (Feb 2020), 3-band TES mode limitations (May 2019–April 2023), and noisy data periods (e.g., May–July 2025), have been mitigated through reprocessing, firmware updates, and instrument recovery. Version 3 products incorporate these improvements where data exists and are unaffected by ongoing issues, but the permanent historical gaps remain, and caution is advised for time-series analyses spanning affected periods.
* Product formats: Version 3 discontinues swath-based (non-gridded) HDF5 products for Level 2 LST&E and Cloud outputs. Only gridded ([ECO_L2G_LSTE](https://doi.org/10.5067/ECOSTRESS/ECO_L2G_LSTE.003) and [ECO_L2G_CLOUD](https://doi.org/10.5067/ECOSTRESS/ECO_L2G_CLOUD.003) in HDF5) and tiled ([ECO_L2T_LSTE](https://doi.org/10.5067/ECOSTRESS/ECO_L2T_LSTE.003) in Cloud-Optimized GeoTIFF) formats are available for Level 2 products. Swath-based products remain available for Level 1 products (e.g., ECO_L1B_RAD, ECO_L1B_GEO). Version 3 discontinues HDF5 products for Level 2 STARS, Level 3 Evapotranspiration, and Level 4 Evaporative Stress Index, and Water Use Efficiency outputs. Only tiled (Cloud-Optimized GeoTIFF) formats remain available for these products. Users transitioning from Version 2 should verify compatibility with the new structures.
* Geolocation considerations: While geolocation is improved in Collection 3 tiled products (fixed MGRS grid), gridded products may reference legacy "GeolocationAccuracyQA" flags. Use "best" and "good" scenes for applications sensitive to precise positioning