Metadata Fields - SMAP L2 Radar/Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture

This page provides a description of all metadata fields within the SMAP L2 Radar/Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture (SPL2SMAP) 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 Description/Valid Values1
DQ_DataQuality DataQualiity

Scope

soil_moisture, downscaled brightness temperature

CompletenssOmission/evaluationMethodType

directInternal

CompletenessOmission/measureDescription

Percentage of grid cells that lack soil moisture retrieval values relative to the total number of grid cells that are attempted for retrieval.

CompletenessOmission/nameOfMeasure

Percentage of Missing Data

CompletenessOmission/value

<A measure between 0 and 100>

CompletenessOmission/unitOfMeasure

Percentage

domainConsistency/evaluationMethodType

directInternal

DomainConsistency/measureDescription

Percentage of grid cells whose soil moisture retrieval values fall within a predefined acceptable range of measure.

DomainConsistency/nameOfMeasure

Percentage of grid cells whose soil moisture retrieval values that are within the Acceptable Range.

DomainConsistency/value

<A measure between 0 and 100>

DomainConsistency/unitOfMeasure

Percentage

EX_Extent Extent

description

The SMAP radar-radiometer based soil moisture retrieval over non-excluded regions from descending (6:00 am) half-orbit Backscatter and TB data.

westBoundLongitude

<Longitude measure between -180 degrees and 180 degrees>

eastBoundLongitude

<Longitude measure between -180 degrees and 180 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

Estimate soil moisture over non-excluded regions from descending (6:00 am) half-orbit radiometer TB data and radar backscatter data. The final result is projected on a 9-km global Earth-fixed grid.

documentation

<A reference to software description document.>

identifier

L2_SM_AP

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

L2_SM_AP_SPS

RFIThreshold

<A threshold the algorithm uses to specify whether a particular measure was contaminated by Radio Frequency Interference.>

timeVariableEpoch

J2000

epochJulianDate

2451545.00

epochUTCDate

2000-01-01T11:58:55.816Z

ATBDTitle

Soil Moisture Active Passive (SMAP) L2_SM_AP Algorithm Theoretical Basis Document

ATBDDate

Oct 2012

ATBDVersion

Preliminary/Initial Release

algorithmDescription

Single channel algorithm

algorithmVersionID

<An algorithm version identifier that runs from 001 to 999>

algorithmMaturity

Beta

LI_Lineage/LE_Source L2_SM_A, L2_SM_P,
9-km global water-body fraction database,
9-km global soil texture database,
9-km global NDVI database,
9-km global soil temperature database,
9-km global surface temperature database,
9-km global DEM database,
9-km global precipitation database,
9-km global urban fraction database,
9-km global IGBP land cover classification database
9-km urban fraction database
9-km snow and ice database
9-km surface roughness database

description

Level 2 Radar Soil Moisture Product ,   Level 2 Radiometer Soil Moisture Product, Static water-body fraction, soil texture, NDVI, soil temperature, surface temperature, DEM, precipitation,  snow/ice, urban fraction, and IGBP land cover classification

fileName

TBD

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 L2_SM_AP data product file was created>

CompositeReleaseID

<SMAP Composite Release ID associated with this data product – See section 3.3>

fileName

<Name of the L2_SM_AP output data file.>

originatorOrganizationName

Jet Propulsion Laboratory

shortName

SPL2SMAP

SMAPShortName

L2_SM_AP

abstract

The SMAP L2_SM_AP product provides soil moisture estimates over non-excluded regions from descending (6:00 am) half-orbit backscatter and TB data. The final result is projected on a 9-km global Earth-fixed grid.

characterSet

utf8

credit

The software that generates the L2_SM_AP product and the data system that automates its production were designed and implemented at the Jet Propulsion Laboratory, California Institute of Technology in Pasadena, California.

Language

eng

purpose

The SMAP L2_SM_AP product delivers soil moisture estimates over non-excluded regions from descending (6:00 am) half-orbit backscatter and TB data. The final result is projected on a 9-km global Earth-fixed grid.

status

on-going

topicCategoryCode

geoscientificInformation

QACreationDate

<The date that the QA product that accompanies the L2_SM_AP data granule was generated.>

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.>

CompositeReleaseID

<SMAP Composite Release ID that identifies the release used to generate this data product – See section 3.3>

longName

SMAP Radiometer Soil Moisture Product.  Soil moisture estimate over a 9-km global Earth-fixed grid.

shortName

SPL2SMAP

identifier_product_DOI

<digital object identifier – TBS>

resourceProviderOrganizationName

National Aeronautics and Space Administration

abstract

The SMAP L2_SM_AP product provides  soil moisture estimates over non-excluded regions from descending (6:00 am) half-orbit backscatter and TB data. The final result is projected on a 9-km global Earth-fixed grid.

characterSet

utf8

credit

The software that generates the L2_SM_AP product and the data system that automates its production were designed and implemented at the Jet Propulsion Laboratory, California Institute of Technology in Pasadena, California.

language

eng

purpose

The SMAP L2_SM_AP product delivers soil moisture estimates over non-excluded regions from descending (6:00 am) half-orbit backscatter and TB data. The final result is projected on a 9-km global Earth-fixed grid.

status

on-going

topicCategoryCode

geoscientificInformation

pointOfContact

National Snow and Ice Data Center, Boulder, Colorado.

PSDPublicationDate

<Date of publication of the Product Specification Document>

PSDEdition

<Edition identifier for the Product Specification Document>

PSDTtitle

Soil Moisture Active Passive Mission L2_SM_AP Product Specification Document

SMAPShortName

L2_SM_AP

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

1.8.9

MD_GridSpatialRepresentation GridSpatialRepresentation

crossTrack/dimensionSize

1

crossTrack/resolution

9 km

track/dimensionSize

N = Number of 9-km global EASE2-Grid cells covered by the radiometer swath

track/resolution

9 km

MD_AcquisitionInformation AcquisitionInformation

platform/antennaRotationRate

14.6 rpm ( 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 1.40 GHz and an L-band radar that operates at 1.26 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

SD_OrbitMeasuredLocation OrbitMeasuredLocation

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

2000-01-01T11:58:55.816Z

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>