ECOSTRESS Overview


Introduction

The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) is aboard the International Space Station (ISS) and measures the temperature of plants to better understand how much water plants need and how they respond to stress. ECOSTRESS was launched to the ISS on June 29, 2018. It has a viewing swath width of around 384 km and views the surface of the Earth from 53.6° N latitude to 53.6° S latitude with variable revisit times, dependent on the orbit of the ISS. Images are acquired over the conterminous U.S. (CONUS), over key biomes around the world, and in European and South Asian agricultural zones and selected FLUXNET validation sites. ECOSTRESS uses a multispectral thermal infrared radiometer to capture radiance of the Earth’s surface in five spectral bands with one shortwave infrared band, and it acquires data at ~70 m spatial resolution. On May 15, 2019, following mass storage unit anomalies, a new data acquisition strategy was implemented for acquiring three of the spectral bands. Learn more on the ECOSTRESS website.

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ECOSTRESS Naming Conventions

ECOSTRESS Filenames

ECOSTRESS filenames (i.e., the local granule ID) follow a naming convention which gives useful information regarding the specific product.

In this example of the swath product, the filename ECOSTRESS_L3_ET_PT-JPL_06660_009_20190908T103729_0600_01.h5 indicates

  • ECOSTRESS – Sensor
  • L3 – Product Level
  • ET_PT-JPL Product Type
  • 06660 – Orbit Number
  • 009 – Scene ID
  • 20190908 – Date of Acquisition (YYYYMMDD)
  • T103729 – Time of Acquisition (HHMMSS) (in UTC)
  • 0600 – Build ID of software that generated product, Major+Minor (2+2 digits)
  • 01 – Product Version Number
  • .h5 – Data Format

ECOSTRESS Product Long Name

The ECOSTRESS Product Long Name (i.e., Collection-Level) convention provides useful information regarding all ECOSTRESS swath products.

Below is an example for an ECOSTRESS Level 3 product, although all ECOSTRESS product Long Names follow the same structure.

The ECOSTRESS Evapotranspiration PT-JPL Daily L3 Global 70 m collection has the following characteristics:

  • ECOSTRESS – Instrument
  • Evapotranspiration PT-JPL – Geophysical Parameter
  • Daily – Temporal Resolution
  • L3 – Processing Level
  • Global – Global Coverage
  • 70 m – Spatial Resolution
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ECOSTRESS Temporal and Spatial Resolution

ECOSTRESS Temporal Resolution

All ECOSTRESS products distributed from the LP DAAC are produced at nominally daily temporal resolution. The true revisit period for a given location is variable based on the instrument’s orbital cycle aboard the ISS.

ECOSTRESS Spatial Resolution

All ECOSTRESS products are produced at 70 m resolution with two exceptions. The ECOSTRESS Evapotranspiration dis-ALEXI USDA Daily L3 Global 30 m and the ECOSTRESS Evaporative Stress Index dis-ALEXI USDA Daily L4 Global 30 m products are produced at 30 m resolution.

ECOSTRESS Coordinate Reference System

All ECOSTRESS products are produced, archived, and distributed as swath products except for (1) the ECOSTRESS Resampled Radiance Daily L1B Global 70 m product, which combines the at-sensor calibrated radiance values retrieved for the ECOSTRESS At-sensor Calibrated Radiance Daily L1B Global 70 m data product and the geolocation information provided in the ECOSTRESS Geolocation Daily L1B Global 70 m data product to produce a geotagged, resampled radiance product; and (2) the ECOSTRESS Evapotranspiration dis-ALEXI USDA Daily L3 Global 30 m and the ECOSTRESS Evaporative Stress Index dis-ALEXI USDA Daily L4 Global 30 m products, which have been resampled to Universal Transverse Mercator (UTM) projection. Below are resources for resampling ECOSTRESS swath products into geolocated, gridded outputs.

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ECOSTRESS Data Processing

ECOSTRESS Processing Levels

The LP DAAC distributes ECOSTRESS data processed to Level-1 or higher:

  • Level-1: Attitude, geolocation, and radiance products
  • Level-2: Land surface temperature and emissivity data retrieved from the Level-1 radiance data, and cloud mask products
  • Level-3: Evapotranspiration products derived from Level-2 data
  • Level-4: Evaporative stress index and water use efficiency products derived from Level-3 data

ECOSTRESS Processing Description

The ECOSTRESS mission generates 12 distributable data products. The products represent four levels of data processing, with data granules defined as an image scene. Each image scene consists of 44 scans of the instrument mirror, each scan taking approximately 1.181 seconds, and each image scene taking approximately 52 seconds. Each image scene starts at the beginning of the first target area encountered during each orbit. Each orbit is defined as the equatorial crossing of an ascending ISS orbit. The ECOSTRESS Science Data Systems (SDS) will acquire, ingest, and store the ECOSTRESS payload and instrument telemetry and ancillary files via its interfaces with the other ground network assets. These data will be both stored for the life-of-mission as well as used for science product generation through Level 4. The SDS will generate Level 0 through Level 2 data products, as well as Level 3 and Level 4 data products using the PT-JPL algorithm. ECOSTRESS science co-investigators at the U.S. Department of Agriculture (USDA) will generate Level 3 and Level 4 data products over select calibration sites using the dis-ALEXI algorithm and deliver them to the SDS. The ECOSTRESS SDS will deliver Level 0 through Level 4 data products to the USGS EROS Center for archival and public distribution. All data residing on the SDS will be subject to access restrictions.

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ECOSTRESS Spectral Bands

Band Emitted Range (band center,
µm)
Band Notes
1 1.660
2 8.285 Unavailable for acquisitions after May
15, 2019
3 8.785
4 9.060 Unavailable for acquisitions after May
15, 2019
5 10.522
6 12.001
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ECOSTRESS Metadata

All metadata that describe the full content of each granule of the ECOSTRESS data product are stored within the explicitly named “/Metadata” Group. The metadata contain valuable information including global attributes and dataset specific attributes pertaining to the granule. Metadata are handled using the same procedures as those that are used to handle data. The contents of each Attribute that store metadata conform to one of the ECOSTRESS Types. Most metadata elements are stored as scalars. A few metadata elements are stored as arrays. The metadata appear in a set of HDF5 Groups under the “/Metadata” Group. These HDF5 Groups contain a set of HDF5 Attributes.

ECOSTRESS standards incorporate additional metadata that describe each HDF5 dataset within the HDF5 file. Each of these metadata elements appear in an HDF5 Attribute that is directly associated with the HDF5 dataset. Wherever possible, these HDF5 Attributes employ names that conform to the Climate and Forecast (CF) conventions. These attributes contain specific SDS information such as the data range and applicable scaling factors for the data. The LP DAAC data products page provides these details within a concise document for each of the products.

Additionally, ECOSTRESS granules contain external ECS metadata. The ECS (generated by the EOSDIS Core System) .met file is the external metadata file in XML format, which is delivered to the user along with the ECOSTRESS product. It provides a subset of the HDF metadata.

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ECOSTRESS Tools and Services

Data access options such as Data Pool, NASA Earthdata Search, AppEEARS, and USGS EarthExplorer can be found under Tools.

All ECOSTRESS standard products are stored in the Hierarchical Data Format version 5 (HDF5). HDF5 is a general purpose file format and programming library for storing scientific data.

Certain open source tools and proprietary tools are available for use with ECOSTRESS HDF5 products:

Open Source Tools

Proprietary Tools

Additional Resources for working with ECOSTRESS data

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