ECOSTRESS Processing Levels

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 swath, gridded, and tiled distributable data products. The products represent four levels of data processing, with data granules defined as an image scene. Each swath and grid 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. Higher level products are also generated in tiled format aligned with the MGRS tiling scheme. The ECOSTRESS SDS will deliver Level 0 through Level 4 data products to the USGS EROS Center for archival and public distribution.

Swath and Grid

All metadata that describe the full content of each granule of the swath or gridded ECOSTRESS data products 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 for swath and gridded data products 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.

Tile

The ECOSTRESS Version 2 tiled products are distributed using the Cloud-Optimized GeoTIFF (COG) format. Each dataset layer is distributed as a separate file. Tiled granules have two sources of metadata: the embedded COG metadata and the external ECS (generated by the EOSDIS Core System) metadata. The COG metadata contains valuable information, including global attributes and dataset specific attributes pertaining to the granule. The ECS .met file is the external metadata file in JSON format.

Swath

ECOSTRESS Level-1 (L1) and Level-2 (L2) products are produced, archived, and distributed as swath products. The ECOSTRESS Swath Geolocation Instantaneous L1B Global 70 m data product is required to georeference the corresponding swath products. Below are resources for resampling ECOSTRESS swath products into geolocated, gridded outputs.

• ECOSTRESS Swath to Grid Conversion Script
• AppEEARS

Grid

ECOSTRESS Level-1C (L1C), Level-2 (L2), Level-3 (L3), and Level-4 (L4) products are distributed as grid products using the letter G in their level identifiers: L1CG/L2G/L3G/L4G. ECOSTRESS L1C/L2G/L3G/L4G gridded data products incorporate the latitude and longitude arrays from the ECOSTRESS Swath Geolocation Instantaneous L1B Global 70 m product to resample the swath data to a 0.0006° grid in WGS84 latitude and longitude.

Tile

ECOSTRESS L1C, L2, L3, and L4 products, except for the L2 Cloud product, are distributed as tile products using the letter T in their level identifiers: L1CG/L2T/L3T/L4T. ECOSTRESS L2T/L3T/L4T tiled data products align with the Military Grid Reference System (MGRS), and its naming convention is derived from the Universal Transverse Mercator (UTM) system. The UTM system divides the Earth’s surface into 60 vertical zones. Each UTM zone has a vertical width of 6° of longitude and horizontal width of 8° of latitude. Each UTM zone is subdivided into MGRS 110 x 110 km zones. ECOSTRESS uses a 70 m cell size with 1568 rows by 1568 columns in each tile. This allows the end user to assume that each 70 m ECOSTRESS pixel will remain in the same location at each timestep observed in analysis.