Metadata Fields - SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures

This page provides a description of all metadata fields within the SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures (SPL1BTB) 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
Representative ISO Class HDF5 Metadata SubGroup HDF5 Subgroup/Attribute Description/Valid Values1
DQ_DataQuality DataQualiity Scope tb_v, tb_h
CompletenssOmission/evaluationMethodType directInternal
CompletenessOmission/measureDescription Percent of radiometer footprints in the product relative to the expected number of footprints that the radiometer should acquire based on the instrument pulse rate and the time period covered by a spacecraft half orbit.
CompletenessOmission/nameOfMeasure Percent of Missing Data
CompletenessOmission/value <A measure between 0 and 100>
CompletenessOmission/unitOfMeasure Percent
RFICompletenssOmission/evaluationMethodType directInternal
RFICompletenessOmission/measureDescription Percent of the radiometer footprints where RFI was detected and the algorithm was unable to remove the RFI contamination relative to the expected number of footprints that the radiometer would acquire based on the instrument pulse rate and the time period covered by a spacecraft half orbit.
RFICompletenessOmission/nameOfMeasure Percent of Data Missing Due to Radio Frequency Interference (RFI)
RFICompletenessOmission/value <A measure between 0 and 100>
RFICompletenessOmission/unitOfMeasure Percent
SubbandCompletenssOmission/evaluationMethodType directInternal
SubbandCompletenessOmission/measureDescription Percent of subband radiometer footprints in the product relative to the expected number of subband footprints that the radiometer should acquire based on the instrument pulse rate and the time period covered by a spacecraft half orbit.
SubbandCompletenessOmission/nameOfMeasure Percent of subband Data
SubbandCompletenessOmission/value <A measure between 0 and 100>
SubbandCompletenessOmission/unitOfMeasure Percent
domainConsistency/evaluationMethodType directInternal
DomainConsistency/measureDescription Percent of brightness temperature measures in the data product that fall within a predefined acceptable range of measure.
DomainConsistency/nameOfMeasure Percent of Brightness Temperatures that fall within Acceptable Range
DomainConsistency/value <A measure between 0 and 100>
DomainConsistency/unitOfMeasure Percent
EX_Extent Extent description The SMAP spacecraft downlinks radiometer data over a 1000 km wide swath. Data acquired over land or over identified external calibration sources are classed as high resolution and contain subband information.  Data acquired over ocean are classed as low resolution and are limited to full band data.
polygonPosList <An array of vertices of a polygon the defines the region occupied by the data set in the corresponding data product. Each vertex is represented by an ordered pair.  Latitudes precede longitudes. Vertices appear in clockwise order. Spaces delineate each value>
westBoundLongitude <Longitude measure between -180 degrees and 179.999 degrees>
eastBoundLongitude <Longitude measure between -180 degrees and 179.999 degrees>
southBoundLatitude <Latitude measure between -90 degrees and 90 degrees>
northBoundLatitude <Latitude measure between -90 degrees and 90 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
stepDateTime <A date time stamp that specifies when the product was generated>
processDescription Converts instrument telemetry into a data set that contains horizontal polarization brightness temperatures, vertical polarization brightness temperatures as well as third and fourth Stokes parameters for each discrete instantaneous field of view acquired by the SMAP radiometer.
documentation <A reference to software description document>
identifier L1B_TB_SPS
RFIThreshold <Specify any run time parameters if they were used>
taFilteredDifferenceThreshold <Threshold value between ta and ta_filtered the signals inability to completely remove RFI contamination for brightness temperature measure>
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 L1B_TB_SPS
timeVariableEpoch J2000
epochJulianDate 2451545.00
epochUTCDate 2000-01-01T11:58:55.816Z
subBandDataPresent <Element that indicates whether subband data are present in the half orbit; valid values include True and False>
ATBDTitle Soil Moisture Active Passive (SMAP) L1B_TB Algorithm Theoretical Basis Document
ATBDDate <Time stamp that specifies the release date of the ATBD>
ATBDVersion <version identifier>
algorithmDescription The Soil Moisture Active Passive (SMAP) radiometer algorithm converts L0 radiometer digital count into calibrated estimates of brightness temperatures within the antenna main beam as referenced to the Earth's surface. Most algorithmic steps are typical implementation for satellite radiometers.  The SMAP algorithm includes two key features that are new for satellite borne radiometers.  These are algorithmic steps that detect and remove radio frequency interference (RFI) detection, as well as measurement of the third and fourth Stokes parameters using digital correlation.
algorithmVersionID <An algorithm version identifier that runs from 001 to 999>
LI_Lineage/LE_Source L1B_Radiometer. Ephemeris. Attitude, Antenna Azimuth. SCLK-UTC Correlation, GMAO_Inst3, SolarRadioFlux, DirectGalaxyLUT, ReflectedGalaxyLUT, ReflectedSunLUT, AntennaPattern,   LeapSeconds, Reconstructed High Resolution Earth Orientation, FullbandCoeffs, SubBandCoeffs, LinearCoeffs, RFIParameters, RFIKurtosisParameter, AntennaPatternCorrection description <Description of each of the lineage products that contribute to generation of the output>
fileName <Complete file name of the input  data product>
creationDate <A date stamp that specifies when the input data product was generated>
version <The SMAP Composite Version ID associated with the input data product>
identifier <The short name associated with the product>
DOI <A digital object identifier associated with the product, if available>
 DS_Dataset/MD_DataIdentification DataSetIdentification creationDate <Date when the L1B_TB data product file was created>
CompositeReleaseID <SMAP Composite Release ID associated with this data product – See section 4.3>
fileName <Name of the L1B_TB output data file>
originatorOrganizationName Jet Propulsion Laboratory
shortName SPL1BTB
SMAPShortName L1B_TB
UUID <A universally unique identifier for each data granule>
ECSVersionID <Identifier that specifies major version delivered to ECS.  Value runs from 001 to 999>
abstract Time ordered geolocated horizontal polarization and vertical polarization brightness temperatures as well as third and fourth Stokes parameters. Each product covers a half orbit with boundaries at the northernmost and southernmost points along the nadir path of the SMAP spacecraft trajectory.
purpose The SMAP L1B_TB Science Processing Software generates data products with sufficient accuracy to retrieve soil moisture at 36 km resolution. Subsequent SMAP processes employ these data, along with radar data acquired simultaneously, to disaggregate the L1B_TB brightness temperatures into higher resolution samples, and thus generate higher resolution soil moisture products.
characterSet utf8
credit The software that generates the Level 1B_TB product was designed and at the Goddard Space Flight Center in Greenbelt, Maryland.  The software was implemented at the Goddard Space Flight Facility as well as at the Jet Propulsion Laboratory, California Institute of Technology, in Pasadena, California. The data system that automates its production was designed and implemented at the Jet Propulsion Laboratory.
language eng
purpose 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.
status onGoing
spatialRepresentationType vector
topicCategory geoscientificInformation
DS_Dataset/MD_DataIdentification/ MD_AggregateInformation QADatasetIdentification creationDate <The date that the QA product that accompanies the L1B_TB data granule was generated>
fileName <The name of QA product>
abstract 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>
CompositeReleaseID <SMAP Composite Release ID that identifies the release used to generate this data product – See section 4.3>
longName SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures
shortName SPL1BTB
identifier_product_DOI http://dx.doi.orgn/10.5067/1V33MVRRLCCT
ECSVersionID <Identifier that specifies major version delivered to ECS. Value runs from 001 to 999>
resourceProviderOrganizationName National Aeronautics and Space Administration
abstract Time ordered geolocated horizontal polarization and vertical polarization brightness temperatures as well as third and fourth Stokes parameters. Each product covers a half orbit with boundaries at the northernmost and southernmost points along the nadir path of the SMAP spacecraft trajectory.
purpose The SMAP L1B_TB Science Processing Software generates data products with sufficient accuracy to retrieve soil moisture at 36 km resolution. Subsequent SMAP processes employ these data, along with radar data acquired simultaneously, to disaggregate the L1B_TB brightness temperatures into higher resolution samples, and thus generate higher resolution soil moisture products.
characterSet utf8
credit The software that generates the Level 1B_TB product was designed and at the Goddard Space Flight Center in Greenbelt, Maryland. The software was implemented at the Goddard Space Flight Facility as well as at the Jet Propulsion Laboratory, California Institute of Technology, in Pasadena, California. The data system that automates its production was designed and implemented at the Jet Propulsion Laboratory.
language eng
status onGoing
spatialRepresentationType vector
topicCategory geoscientificInformation
pointOfContact National Snow and Ice Data Center, Boulder, Colorado
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 1.8.11
ProductSpecificationDocument language eng
characterSet utf8
publicationDate <Date of publication of the Product Specification Document>
edition <Edition identifier for the Product Specification Document>
title Soil Moisture Active Passive Mission L1B_TB Product Specification Document
SMAPShortName L1B_TB
MD_AcquisitionInformation AcquisitionInformation platform/antennaRotationRate 14.6 rpm OR 13.0 rpm
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 1.41 GHz and an L-band radar that operates at 1.25 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
argumentOfPerigee <The angle in the satellite's orbit plane between the point of perigee and ascending node. The angle is measured in the direction of spacecraft motion>
cycleNumber <The SMAP satellite flies in a cycle the repeats after 117 orbits. This element specifies the cycle of orbits when the data were taken. First cycle is assigned the number 1>
eccentricity <The eccentricity of the satellite orbit>
epoch <The effective time of the data in the OrbitMeasuredLocation class. This may be identical to the equatorCrossingDateTime>
equatorCrossingDateTime <A time stamp that specifies the date and time of ascending node crossing for the current orbit>
equatorCrossingLongitude <The longitude of the ascending node crossing for the current orbit>
inclination <The angle between the spacecraft's orbital plane and the Earth's equatorial plane. An angle greater than 90 degrees indicates a orbit retrograde path>
meanMotion <The constant angular speed that would be required for a body travelling in an undisturbed elliptical orbit with the specified semi-major axis to complete one revolution in the actual orbital period, expressed as a number of revolutions per day>
orbitDirection <SMAP Level 1 and Level 2 products appear in half orbit granules. This element provides direction of orbital path relative to equatorial plane. Values are "ascending" or "descending":>
halfOrbitStartDateTime <A time stamp that specifies the date and time of the instant the spacecraft crosses either the southernmost point or the northernmost point in its path, marking the beginning of the half orbit>
halfOrbitStopDateTime <A time stamp that specifies the date and time of the instant the spacecraft crosses either the southernmost point or the northernmost point in its path, marking the end of the half orbit>
orbitPathNumber < The SMAP satellite flies in a cycle the repeats after 117 orbits. This element specifies which of the 117 possible paths the spacecraft flew when the data in the file were acquired. The orbitPathNumber  varies from 1 to 117>
orbitPeriod <Time required to complete a the spacecraft orbit>
reference_CRS <A description of the coordinate reference system used to describe spacecraft orbital data>
revNumber <The count of orbits from beginning of mission to the orbit that the spacecraft flew when the data in the file were acquired.  Orbit zero begins at launch and extends until the spacecraft crosses the southernmost point in its path for the first time. Orbit one commences at that instant>
rightAscensionAscendingNode <The angle eastward on the equatorial plan from the vernal equinox to the orbit ascending node>
semiMajorAxis <The length of the semi-major axis of the spacecraft orbit>
1 Brackets 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>