ECO_L2T_STARS v002

ECOSTRESS Tiled Ancillary NDVI and Albedo L2 Global 70 m


PI: Simon Hook, Gregory Halverson, Margaret Johnson, Kerry Cawse-Nicholson

Description

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 as well as key biomes and agricultural zones around the world and selected FLUXNET validation sites. A map of the acquisition coverage can be found on the ECOSTRESS website.

The ECOSTRESS Tiled Ancillary NDVI and Albedo Level 2 Global 70 m (ECO_L2T_STARS) Version 2 data product provides Normalized Difference Vegetation Index (NDVI) and albedo aligned with each daytime ECOSTRESS overpass. ECO_L2T_STARS is an ancillary data product derived from Visible Infrared Imaging Radiometer Suite (VIIRS) and Harmonized Landsat Sentinel (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) 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 3.1 of the ECOSTRESS Jet Propulsion Laboratory (JPL) EvapoTranspiration (JET) Level-3 Algorithm Theoretical Basis Document (ATBD) for further details of the Bidirectional Reflectance Distribution Function (BRDF) implementation and albedo calculations.

The ECO_L2T_STARS Version 2 data product is provided in Cloud Optimized GeoTIFF (COG) format using a modified version of the Military Grid Reference System (MGRS), 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 band is distributed as a separate COG. This product contains four layers including NDVI, NDVI uncertainty, albedo, and albedo uncertainty. The ECO_L2T_STARS ancillary NDVI and albedo product is only generated for corresponding daytime ECOSTRESS Tiled Land Surface Temperature and Emissivity Instantaneous Level 2 Global 70 m (ECO_L2T_LSTE) Version 2 tiles.

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Characteristics

Collection and Granule

Collection

Characteristic Description
CollectionECOSTRESS
DOI10.5067/ECOSTRESS/ECO_L2T_STARS.002
File Size~20 MB
Temporal ResolutionVaries
Temporal Extent2018-07-09 to Present
Spatial ExtentGlobal (+/- 52 degrees latitude)
Coordinate SystemUniversal Transverse Mercator (UTM)
DatumWorld Geodetic System (WGS84)
File FormatCloud Optimized GeoTIFF (COG)
Geographic Dimensions109.8 km x 109.8 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers4
Columns/Rows1568 x 1568
Pixel Size70 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
NDVI Normalized Difference Vegetation Index N/A 32-bit floating point NaN NaN -1 to 1 N/A
NDVI-UQ Normalized Difference Vegetation Index Uncertainty N/A 32-bit floating point NaN NaN -1 to 1 N/A
albedo Albedo N/A 32-bit floating point NaN NaN 0 to 1 N/A
albedo-UQ Albedo Uncertainty N/A 32-bit floating point NaN NaN 0 to 1 N/A

Product Quality

Quality information for the ECO_L2T_STARS data product is not available.

Known Issues

  • Data acquisition gap: ECOSTRESS was launched on June 29, 2018, and moved to autonomous science operations on August 20, 2018, following a successful in-orbit checkout period. On September 29, 2018, ECOSTRESS experienced an anomaly with its primary mass storage unit (MSU). ECOSTRESS has a primary and secondary MSU (A and B). On December 5, 2018, the instrument was switched to the secondary MSU and science operations resumed. On March 14, 2019, the secondary MSU experienced a similar anomaly, temporarily halting science acquisitions. On May 15, 2019, a new data acquisition approach was implemented, and science acquisitions resumed. To optimize the new acquisition approach TIR bands 2, 4, and 5 are being downloaded. The data products are as previously, except the bands not downloaded contain fill values (L1 radiance and L2 emissivity). This approach was implemented from May 15, 2019, through April 28, 2023.

  • Data acquisition gap: From February 8 to February 16, 2020, an ECOSTRESS instrument issue resulted in a data anomaly that created striping in band 4 (10.5 micron). These data products have been reprocessed and are available for download. No ECOSTRESS data were acquired on February 17, 2020, due to the instrument being in SAFEHOLD. Data acquired following the anomaly have not been affected.

  • Data acquisition: ECOSTRESS has now successfully returned to 5-band mode after being in 3-band mode since 2019. This feature was successfully enabled following a Data Processing Unit firmware update (version 4.1) to the payload on April 28, 2023. To better balance contiguous science data scene variables, 3-band collection is currently being interleaved with 5-band acquisitions over the orbital day/night periods.


About the image

NDVI over northern Mongolia from the ECO_L2T_STARS V002 product on October 20th, 2023.

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Documentation

User Guide
Algorithm Theoretical Basis Document (ATBD)
Product Specification Document (PSD)
Algorithm Specification Document (ASD)

Using the Data

Access Data

Citation

DOI: 10.5067/ECOSTRESS/ECO_L2T_STARS.002