Metadata Fields - SMAP L4 Global 3-hourly 9 km Surface and Rootzone Soil Moisture

This page provides a description of all metadata fields within the SMAP L4 Global 3-hourly 9 km Surface and Rootzone Soil Moisture product. All metadata fields are described in Table 1.

For a description of data fields for this product, refer to the Data Fields document.

Table 1. Description of File Level Metadata Fields
ISO Major Class SMAP HDF5 Metadata SubGroup Subgroup/Attribute in SMAP HDF5 Valid Values1 Product
DQ_DataQuality DataQuality/TBH Scope tb_h_forecast aup
CompletenessOmission/evaluationMethodType directInternal
CompletenessOmission/measureDescription Percent of land grid cells (excluding inland water and permanent ice) that lack H-polarized model forecast Tb data relative to the total number of land grid cells that fall within the global domain (excluding inland water and permanent ice). Model forecast Tb is only computed where SMAP Tb observations are assimilated.
CompletenessOmission/nameOfMeasure Percent of Missing Data
CompletenessOmission/value <A measure between 0 and 100>
CompletenessOmission/unitOfMeasure Percent
DomainConsistency/evaluationMethodType directInternal
DomainConsistency/measureDescription Percent of geophysical data that fall within a predefined acceptable range of measure.
DomainConsistency/nameOfMeasure Percent of geophysical data that are within the acceptable range.
DomainConsistency/value <A measure between 0 and 100>
DomainConsistency/unitOfMeasure Percent
DataQuality/TBV Scope tb_v_forecast aup
CompletenessOmission/evaluationMethodType directInternal
CompletenessOmission/measureDescription Percent of land grid cells (excluding inland water and permanent ice) that lack V-polarized model forecast Tb data relative to the total number of land grid cells that fall within the global domain (excluding inland water and permanent ice). Model forecast Tb is only computed where SMAP Tb observations are assimilated.
CompletenessOmission/nameOfMeasure Percent of Missing Data
CompletenessOmission/value <A measure between 0 and 100>
CompletenessOmission/unitOfMeasure Percent
DomainConsistency/evaluationMethodType directInternal
DomainConsistency/measureDescription Percent of geophysical data that fall within a predefined acceptable range of measure.
DomainConsistency/nameOfMeasure Percent of geophysical data that are within the acceptable range.
DomainConsistency/value <A measure between 0 and 100>
DomainConsistency/unitOfMeasure Percent
DataQuality/SM Scope sm_rootzone gph
CompletenessOmission/evaluationMethodType directInternal
CompletenessOmission/measureDescription Percent of land grid cells (excluding inland water and permanent ice) that lack root zone soil moisture data relative to the total number of land grid cells that fall within the global domain (excluding inland water and permanent ice).
CompletenessOmission/nameOfMeasure Percent of Missing Data
CompletenessOmission/value <A measure between 0 and 100>
CompletenessOmission/unitOfMeasure Percent
DomainConsistency/evaluationMethodType directInternal
DomainConsistency/measureDescription Percent of geophysical data that fall within a predefined acceptable range of measure.
DomainConsistency/nameOfMeasure Percent of geophysical data that are within the acceptable range.
DomainConsistency/value <A measure between 0 and 100>
DomainConsistency/unitOfMeasure Percent
EX_Extent Extent description Global land excluding inland water and permanent ice. gph, aup, lmc (except time range)
westBoundLongitude -180 degrees
eastBoundLongitude 180 degrees
southBoundLatitude - 85.0445664 degrees
northBoundLatitude 85.0445664 degrees
rangeBeginningDateTime <Time stamp that indicates the initial time element in the product.>
rangeEndingDateTime <Time stamp that indicates the final time of data in the product.>
LI_Lineage/LE_ProcessStep ProcessStep processor Soil Moisture Active Passive (SMAP) Mission Science Data System (SDS) Operations Facility gph, aup, lmc
stepDateTime <A date time stamp that specifies when the processing of the data product took place.>
processDescription Assimilates Level 1 and Level 2 SMAP data into a global land surface model to generate spatially complete and temporally continuous estimates of soil moisture and associated land surface conditions.
documentation <Document title.>
documentDate <Document release/publication date (ccyy-mm-dd).>
documentVersion <Document version identifier.>
identifier L4_SM_SPS
runTimeParameters <Specify any run time parameters if they were used.>
SWVersionID <A software version identifier that runs from 001 to 999>
softwareDate <A date stamp that specifies when software used to generate this product was released.>
softwareTitle Level 4 Surface and Root Zone Soil Moisture SPS
timeVariableEpoch J2000
epochJulianDate 2451545.00
epochUTCDate 2000-01-01T11:58:55.816Z
ATBDTitle Soil Moisture Active Passive (SMAP) Level 4 Surface and Root Zone Soil Moisture (L4_SM) Algorithm Theoretical Basis Document (ATBD)
ATBDDate <Time stamp that specifies the release date of the ATBD>
ATBDVersion <Latest ATBD version number.>
algorithmDescription The L4_SM algorithm is a customized, off-line (land- only) version of the ensemble-based NASA GEOS-5 land data assimilation system. It merges SMAP observations with estimates from a land surface model that is driven with observations-based precipitation forcing.
algorithmVersionID <An algorithm version identifier that runs from 001 to 999>
LI_Lineage/LE_Source Source/L1C_TB description The SMAP Level 1C Brightness Temperature product, which contains the assimilated SMAP radiometer brightness temperatures on 36 km EASE-Grid 2.0. aup
fileName <Complete file name(s) of the input data product(s).>
creationDate <Date stamp(s) of the input data product(s).>
version <The SMAP Composite Release ID(s) of the input data product(s).>
identifier SPL1CTB
DOI <Digital object identifier(s) of the input data product(s), if available.>
Source/L2_SM_AP description The SMAP Level 2 Active/Passive Soil Moisture product which contains assimilated SMAP radiometer brightness temperatures downscaled to 9 km EASE- Grid 2.0 through combination with SMAP radar backscatter observations. aup
fileName <Complete file name(s) of the input data product.>
creationDate <Date stamp(s) of the input data product(s).>
version <The SMAP Composite Release ID(s) of the input data product(s).>
identifier SPL2SMAP
DOI <Digital object identifier(s) of the input data product(s), if available.>
Source/L2_SM_A description The SMAP Level 2 Active Soil Moisture product which contains the assimilated SMAP radar-based freeze- thaw indicator. aup
fileName <Complete file name(s) of the input data product.>
creationDate <Date stamp(s) of the input data product(s).>
version <The SMAP Composite Release ID(s) of the input data product(s).>
identifier SPL2SMA
DOI <Digital object identifier(s) of the input data product(s), if available.>
Source/GEOS5_lfo description The surface meteorological data from the NASA GEOS-5 system that are used to force the land surface model component of the L4_SM algorithm. gph
fileName <Complete file name(s) of the input data product.>
creationDate <Date stamp(s) of the input data product(s).>
version <Version ID(s) of the input data product(s).>
identifier <Short name(s) of the input data product(s).>
DOI <Digital object identifier(s) of the input data product(s), if available.>
Source/GEOS5_lfo_corr description The observation-corrected surface meteorological data from the NASA GEOS-5 system. Precipitation corrected using the gauge-based NOAA Climate Prediction Center Unified precipitation product. gph
fileName <Complete file name(s) of the input data product.>
creationDate <Date stamp(s) of the input data product(s).>
version <Version ID(s) of the input data product(s).>
identifier <Short name(s) of the input data product(s).>
DOI <Digital object identifier(s) of the input data product(s), if available.>
DS_Dataset/MD_DataIdentification DataSetIdentification creationDate <Date when the L4_SM data product file was created> gph, aup, lmc
VersionID <SMAP Science Version ID associated with this data product – See section 4.3 of the L4_SM Product Specification Document.>
CompositeReleaseID <SMAP Composite Release ID (CRID) associated with this data product. The CRID is the Science Version ID with a four-digit appendix. – See section 4.3 of the L4_SM Product Specification Document.>
ECSVersionID <Three-character string that identifies the type of ECS data stream and, for the operational streams, reflects the major science version of the product, for example: "001" = first operational processing stream; "002" = second operational processing stream (supersedes first stream after major algorithm update and includes reprocessing); "003" = third operational processing stream (supersedes second stream…); "199" = candidate operational stream (a.k.a. OASIS or parallel processing stream) > 
UUID <Universally Unique identifier (36-character string)>
fileName <Name of the L4_SM output data file.>
originatorOrganizationName NASA Global Modeling and Assimilation Office, Goddard Space Flight Center, Greenbelt, Maryland, USA
longName SMAP Level 4 Surface and Root Zone Soil Moisture <Collection ID> Collection
shortName <ECS Short Name>
SMAPShortName L4_SM_<Collection ID>
abstract The SMAP L4_SM data product provides global, 3- hourly surface and root zone soil moisture at 9 km resolution. The L4_SM data product consists of three Collections of data granules (or files): the geophysical data Collection (shortName=SPL4SMGP), the analysis update data Collection (shortName=SPL4SMAU), and the land model constants data Collection (shortName=SPL4SMLM).
characterSet utf8
credit The software that generates the L4_SM data product and the data system that automates its production were designed and implemented at the NASA Global Modeling and Assimilation Office, Goddard Space Flight Center, Greenbelt, Maryland, USA.
language eng
purpose The SMAP L4_SM data product provides spatially and temporally complete surface and root zone soil moisture information for science and applications users.
status "on-going" ("completed" after final reprocessing)
topicCategoryCode geoscientificInformation
QACreationDate <The generation date of the QA product that accompanies the L4_SM data granule.>
QAFileName <The name of QA product.>
QAAbstract An ASCII product that contains statistical information on data product results. These statistics enable data producers and users to assess the quality of the data in the data product granule.
DS_Series/MD_DataIdentification SeriesIdentification revisionDate <Date and time of the software release that was used to generate this data product.> gph, aup, lmc
VersionID <SMAP Science Version ID associated with this data product – See section 4.3 of the L4_SM Product Specification Document.>
CompositeReleaseID <SMAP Composite Release ID (CRID) associated with this data product. The CRID is the Science Version ID with a four-digit appendix. – See section 4.3 of the L4_SM Product Specification Document.>
ECSVersionID <Three-character string that identifies the type of ECS data stream and, for the operational streams, reflects the major science version of the product, for example: "001" = first operational processing stream; "002" = second operational processing stream (supersedes first stream after major algorithm update and includes reprocessing); "003" = third operational processing stream (supersedes second stream…); "199" = candidate operational stream (a.k.a. OASIS or parallel processing stream) > 
longName SMAP Level 4 Surface and Root Zone Soil Moisture <Collection ID> Collection
shortName < ECS Short Name>
identifier_product_DOI <digital object identifier>
resourceProviderOrganizationName National Aeronautics and Space Administration
abstract The SMAP L4_SM data product provides global, 3- hourly surface and root zone soil moisture at 9 km resolution. The L4_SM data product consists of three Collections of data granules (or files): the geophysical data Collection (shortName=SPL4SMGP), the analysis update data Collection (shortName=SPL4SMAU), and the land model constants data Collection (shortName=SPL4SMLM).
characterSet utf8
credit The software that generates the L4_SM data product and the data system that automates its production were designed and implemented at the NASA Global Modeling and Assimilation Office, Goddard Space Flight Center, Greenbelt, Maryland, USA.
language Eng
purpose The SMAP L4_SM data product provides spatially and temporally complete surface and root zone soil moisture information for science and applications users.
status "on-going" ("completed" after final reprocessing)
topicCategoryCode geoscientificInformation
pointOfContact National Snow and Ice Data Center, Boulder, Colorado, USA.
PSDPublicationDate <Date of publication of the Product Specification Document>
PSDEdition <Edition identifier for the Product Specification Document>
PSDTtitle Soil Moisture Active Passive Mission Level 4 Surface and Root Zone Soil Moisture (L4_SM) Product Specification Document
SMAPShortName L4_SM_<Collection_ID>
mission Soil Moisture Active Passive (SMAP)
maintenanceAndUpdateFrequency asNeeded
maintenanceDate <Specifies a date when the next update to this product might be anticipated.>
format HDF5
formatVersion <HDF5 version number>
MD_GridSpatialRepresentation GridSpatialRepresentation Latitude/dimensionSize 1624 gph, aup, lmc
Latitude/resolution 9 km on average
Longitude/dimensionSize 3856
Longitude/resolution 9 km on average
MD_AcquisitionInformation AcquisitionInformation platform/antennaRotationRate <Antenna rotation rate in rpm> gph, aup
platformDocument/publicationDate <The date of publication of the document that describes the SMAP platform, if available to the general public.>
platformDocument/edition <The edition of publication of the document that describes the SMAP platform, if available to the general public.>
platformDocument/title <The title of the publication of the document that describes the SMAP platform, if available to the general public.>
platform/description The SMAP observatory houses an L-band radiometer that operates at 1.4 GHz and an L-band radar that operates at 1.26-1.29 GHz. The instruments share a rotating reflector antenna with a 6 meter aperture that scans over a 1000 km swath. The bus is a 3 axis stabilized spacecraft that provides momentum compensation for the rotating antenna.
platform/identifier SMAP
radarDocument/publicationDate <The date of publication of the document that describes the SMAP radar instrument, if available to the general public.>
radarDocument/edition <The edition of publication of the document that describes the SMAP radar instrument, if available to the general public.>
radarDocument/title <The title of the publication of the document that describes the SMAP radar instrument, if available to the general public.>
radar/description The SMAP radar instrument employs an L-band conically scanned system and SAR processing techniques to achieve moderate resolution (1 km) backscatter measurements over a very wide 1000 km swath.
radar/identifier SMAP SAR
radar/type L-band Synthetic Aperture Radar
radiometerDocument/publicationDate <The date of publication of the document that describes the SMAP radiometer instrument, if available to the general public.>
radiometerDocument/edition <The edition of publication of the document that describes the SMAP radiometer instrument, if available to the general public.>
radiometerDocument/title <The title of the publication of the document that describes the SMAP radiometer instrument, if available to the general public.>
radiometer/description The SMAP L-band Radiometer records V-pol, H-pol, 3rd and 4th Stokes brightness temperatures at 40 km resolution at 4.3 Megatbits per second with accuracies of 1.3 Kelvin or better.
radiometer/identifier SMAP RAD
radiometer/type L-band Radiometer
1Brackets indicate a description of potential valid values, not an absolute value. For example, valid values for the Subgroup algorithmVersionID range from 001 to 999, which is indicated by the following description: <An algorithm version identifier that runs from 001 to 999>