ECO3ETALEXI v001

ECOSTRESS Evapotranspiration dis-ALEXI Daily L3 CONUS 70 m


PI: Simon Hook, 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 over the conterminous United States (CONUS) 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 NASA Jet Propulsion Laboratory (JPL) ECO3ETALEXI Version 1 data product provides estimates of daily evapotranspiration (ET) using the ECOSTRESS Level 2 (L2) land surface temperature and emissivity (LST&E) product, along with ancillary meteorological data and remotely sensed vegetation cover information. The ECO3ETALEXI data product is derived using a physics-based surface energy balance (SEB) algorithm, the Atmosphere Land Exchange Inverse (ALEXI) Disaggregation algorithm (DisALEXI). Described in the Algorithm Theoretical Basis Document (ATBD), DisALEXI is based on spatial disaggregation of regional-scale fluxes from the ALEXI SEB model. There are many approaches for spatially mapping ET; however, SEB methods are favored for remote sensing retrievals based on land-surface temperature. ALEXI was initially developed for managed landscapes and has now been evaluated in comparison with micrometeorological flux tower observations over crop, forest, grassland, wetland, and semiarid desert sites. Applications include crop water use, crop phenology monitoring, and drought early warning or water stress detection. ECO3ETALEXI is available for CONUS at 70-meter (m) pixel resolution.

The ECO3ETALEXI Version 1 data product contains layers of daily ET, ET uncertainty, and associated quality flags. A low-resolution browse is also available showing daily ET as a stretched image with a color ramp in JPEG format.

read more

Characteristics

Collection and Granule

Collection

Characteristic Description
CollectionECOSTRESS
DOI10.5067/ECOSTRESS/ECO3ETALEXI.001
File Size~290 MB
Temporal ResolutionDaily
Temporal Extent2018-07-15 to Present
Spatial ExtentCONUS
Coordinate SystemGeographic Latitude and Longitude
DatumWorld Geodetic System (WGS84)
File FormatHDF5
Geographic Dimensions400 km x 400 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers3
Columns/Rows5400 x 5632
Pixel Size70 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
ETdaily Evapotranspiration Daily mm/day 32-bit floating point 9999 N/A 0 to 30 N/A
ETdailyUncertainty Evapotranspiration Daily Uncertainty mm/day 32-bit floating point 9999 N/A 0 to 30 N/A
QualityFlag Quality Flag N/A 16-bit unsigned integer 9999 N/A 0 to 15 N/A

Product Quality

Quality information for the ECO3ETALEXI Version 1 data product is provided in section 2.4 of the User Guide.

Known Issues

• Data acquisition gaps: 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, only TIR bands 2, 4, and 5 are being downloaded. The data products are the same as before, but the bands not downloaded contain fill values (L1 radiance and L2 emissivity).

• 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.


About the image

ECOSTRESS evapotranspiration daily data from ECO3ETALEXI product over Wisconsin, United States, acquired May 29, 2021.

View full-size image

Documentation

User Guide
Algorithm Theoretical Basis Document (ATBD)
Earthdata Search Quick Guide

Using the Data

Access Data

Citation

DOI: 10.5067/ECOSTRESS/ECO3ETALEXI.001