2026-06-27T04:51:13Zhttp://nsidc.org/api/dataset/metadata/oaioai:nsidc.org/SPL1AP.0022026-06-24T19:16:46Zcumulusnasa_nsidc_daac
SPL1AP.002SMAP L1A Radiometer Time-Ordered Parsed TelemetryPiepmeier, J. R., Kim, E. J., Mohammed, P., Peng, J. & Ruf, C.SMAP L1A Radiometer Time-Ordered Parsed Telemetry2015-10-30Boulder, Colorado USANASA NSIDC DAAC: NASA National Snow and Ice Data Center Distributed Active Archive Center2false10.5067/JGV8EY3FGAH1https://nsidc.org/sites/default/files/spl1ap-v002-userguide.pdfSPL1APTechnical ContactNSIDCUser Servicesnsidc@nsidc.org1-303-492-61991-303-492-2468CIRES, 449 UCBUniversity of ColoradoBoulderCO80309-0449USAEARTH SCIENCESPECTRAL/ENGINEERINGMICROWAVESENSOR COUNTS Climatology/Meteorology/AtmosphereGeoscientific InformationEASE-Grid SM-projectL1Raw Observation CountsRAW TELEMETRY DATASMAP-projectSMAP-project-L1Soil Moisture Active PassiveSMAP L-BAND RADIOMETERSMAP L-Band RadiometerSMAPSoil Moisture Active and Passive Observatory2015-03-31active-86.486.4-180180GEOGRAPHIC REGIONGLOBAL LAND40 km40 km49 minuteSMAP data sets provide multiple means to assess quality. Each data set contains bit flags, uncertainty measures, and file-level metadata that provide quality information. The Data Fields and Metadata Fields documents describe the specific bit flags, uncertainty measures, and file-level metadata contained in this data set.
Each SMAP HDF5 data file contains metadata with Quality Assessment (QA) metadata flags. These QA metadata flags are calculated and set by the SDS at JPL prior to delivery to the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). A separate, ISO 19115-compliant metadata file with an .xml file extension is also delivered to NSIDC DAAC with the HDF5 data file; it contains the same information as the file-level metadata.
A separate QA file with a .qa file extension is also associated with each data file. QA files are ASCII text files that contain statistical information in order to help users better assess the quality of the associated data file.
In addition, various levels of QA are conducted with the Level-1A data. If a file passes QA, the SDS applies that file for higher-level processing, browse generation, active science QA, and data archive and distribution. If a product fails QA, it is never delivered to NSIDC DAAC.These data are freely, openly, and fully accessible, provided that you are logged into your NASA Earthdata profile (https://urs.earthdata.nasa.gov/).These data are freely, openly, and fully available to use without restrictions, provided that you cite the data according to the recommended citation at https://nsidc.org/about/use_copyright.html. For more information on the NASA EOSDIS Data Use Policy, see https://earthdata.nasa.gov/earth-observation-data/data-use-policy.EnglishNASA/JPL/SMAPNASA NSIDC DAACNASA National Snow and Ice Data Center Distributed Active Archive Centerhttps://nsidc.org/daacData Center ContactNSIDCUser Servicesnsidc@nsidc.org1-303-492-6199National Snow and Ice Data CenterCIRES, 449 UCBUniversity of ColoradoBoulderCO80309-0449USAHTTPS36.4 GBHDF5Entekhabi, D. et al. 2014. SMAP Handbook–Soil Moisture Active Passive: Mapping Soil Moisture and Freeze/Thaw from Space. Pasadena, CA USA: SMAP Project, JPL CL#14-2285, Jet Propulsion Laboratory. (https://smap.jpl.nasa.gov/files/smap2/SMAP_Handbook_FINAL_1_JULY_2014_Web.pdf, 4.09 MB)
Mohammed-Tano, P. 2015. Soil Moisture Active Passive (SMAP) Project Level 1A Radiometer Product Specification Document. Pasadena, CA USA: SMAP Project, JPL D-92340, Jet Propulsion Laboratory. (http://nsidc.org/data/docs/daac/smap/sp_l1a_p/pdfs/D-92340-A_SMAP_Radiometer_Level1A_Product_Specification_Document_150720_with sigs.pdf, 979 KB)
Piepmeier, J. R. et al. 2016. SMAP Algorithm Theoretical Basis Document: L1B Radiometer Product: Includes L1A and L1B. SMAP Project, NASA GSFC SMAP-006, NASA Goddard Space Flight Center, Greenbelt, MD. (http://nsidc.org/data/docs/daac/smap/sp_l1b_tb/pdfs/SMAP_ATBD_RadiometerL1B_TB_REV-B_20150401.pdf, 1.94 MB)Each Level-1A (L1A) granule incorporates all radiometer data downlinked from the Soil Moisture Active Passive (SMAP) spacecraft for one specific half orbit. The data are scaled instrument counts consisting of the first four raw moments of the fullband channel (vertical and horizontal polarizations); the complex cross-correlations of the fullband channel; and the 16 subband channels (vertical and horizontal polarizations).VIEW RELATED INFORMATIONhttps://nsidc.org/sites/default/files/spl1ap-v002-userguide.pdfSMAP L1A Radiometer Time-Ordered Parsed Telemetry, Version 2 User GuideGET DATAhttps://search.earthdata.nasa.gov/search/granules?p=C2938661641-NSIDC_CPRDEarthdata SearchGET DATAhttps://cmr.earthdata.nasa.gov/virtual-directory/collections/C2938661641-NSIDC_CPRDHTTPSGET DATAhttps://nsidc.org/data/data-access-tool/SPL1AP/versions/2/Data Access ToolGET DATAhttps://earthaccess.readthedocs.io/en/stable/earthaccessCEOS IDN DIFVERSION 9.92015-10-302026-06-24NSIDCVersion SummaryChanges to this version include:
<ul><li>Transitioned to Validated-Stage 2</li>
<li>Calibration parameters were adjusted to reduce calibration jumps and drift previously present in the Beta-release; as a result, calibration now meets its less than 0.4 K/month stability back to 31 March 2015</li>
<li>Additional bit-error checking was performed on Level-0 instrument telemetry</li>
</ul>
For the full major and minor version history, go to <a href="https://nsidc.org/data/smap/version-history">https://nsidc.org/data/smap/version-history</a>NSIDCMinor VersionR12170Changed with Version 2 update. 2015-03-312015-12-151R12240No science change. Minor version incremented to coincide with changes made for radar and SPL2SMP processing.2015-12-172016-01-062R12241No science change. Minor version incremented to coincide with changes made to the radiometer reflector table for SPL1BTB V2 and SPL1CTB V2.2016-01-062016-04-213R13080No science change. CRID incremented to coincide with the Version 3 release of L1B through L3 products.2015-11-182016-12-074R14010No science change. CRID incremented to coincide with the release of the following: enhanced products, including SPL1CTB_E, SPL2SMP_E, SPL3SMP_E, SPL3FTP_E (Version 1); SPL3FTP (Version 1); and SPL2SMP, SPL3SMP (Version 4).2015-03-312017-04-245R15060Changes to this version include:
Processing capabilities for the upcoming SMAP/Sentinel-1 radiometer/radar soil moisture product
SPL1BTB processing change to Atmospheric Correction to ensure proper unit conversion
Changes to resolve bugs that were causing SPL1BTB_E processing to fail
Note: Temporal coverage for CRID R15060 varies slightly; though the majority of R15060 files begin at 2017-04-24 (11:00), some R15060 files appear earlier in the time series.
2017-04-242017-09-066R15152 <ul><li>Updated compiler optimization flag in radiometer processor to reduce run time</li>
<li>Compiled optimization flags</li>
<li>Bug fix for initialization error (error surfaced by optimization flags)</li>
<li>Note that the data content/quality has not changed</li>
</ul>2017-09-032017-11-147R15180No science change. CRID incremented to coincide with release of the new SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture (SPL2SMAP_S) product.2017-10-262018-01-098R15181No science change. CRID incremented to coincide with an update to the radiometer reflector ancillary file for January and February 2018.2017-12-102018-03-149R15182No science change. CRID incremented to coincide with an update to the radiometer reflector ancillary file for January through December 2018. 2018-03-1410R16000No science change. CRID incremented to coincide with major version update for all L1-L3 SMAP radiometer products with the exception of SPl2SMAP_S.2018-06-012018-06-1411R16010No science change. CRID incremented to coincide with updates to L1-L3 radiometer products.2015-03-312018-11-0712R16020No science change. CRID incremented to coincide with TB and half-orbit correction for SPL3SMP, SPL2SMP_E, and SPL3SMP_E products.2018-11-062018-12-3113R16022No science change. CRID incremented to coincide with an update to the radiometer reflector ancillary file for January through December 2019.2018-12-312019-08-1314R16510No science change. CRID incremented to coincide with the release of SPL2SMP V6, SPL2SMP_E V3, SPL3SMP V6, and SPL3SMP_E V3.2019-08-112019-12-2315R16515No science change. CRID incremented to coincide with an update to the radiometer reflector ancillary file for January through December 2020.2019-12-212020-08-2716R17000No science change. CRID incremented to coincide with updates to L1-L3 radiometer products.2020-08-272021-04-2917R17030No science change. CRID incremented to coincide with ASA correction for SPL1BTB.2021-04-2917NSIDCCurrent Version1NSIDCLevel of ServiceComprehensiveNSIDCFull Dataset CitationPiepmeier, J. R., Kim, E. J., Mohammed, P., Peng, J. & Ruf, C. (2015). <i>SMAP L1A Radiometer Time-Ordered Parsed Telemetry</i>. (SPL1AP, Version 2). [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. <a href="https://doi.org/10.5067/JGV8EY3FGAH1">https://doi.org/10.5067/JGV8EY3FGAH1</a>. [<i><describe subset used if applicable></i>].NSIDCRetiredfalseNSIDCRelated Servicesapplication/vnd.nasa.cmr.umm+jsonfalsebookerlmmt_service_52052S3107386427-NSIDC_CPRDNSIDC_CPRD3service2024-12-03T17:04:33.698Zhttps://cmr.earthdata.nasa.gov/virtual-directory/collections/NSIDC_CPRD_HTTPS_File_SystemNOT PROVIDED1HTTPS File SystemQuickly download a few files using a web browser, or access data through a command-line utility such as WGET.https://nsidc.org/data/user-resources/help-center/nasa-earthdata-cloud-data-access-guide#anchor-download-to-a-local-computer-from-earthdata-cloudVIEW RELATED INFORMATIONNASA Earthdata Cloud Data Access GuidePublicationURLUSER SERVICESNSIDC DAAC User ServicesEmailnsidc@nsidc.orgDATA ACCESS/RETRIEVALDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESSee https://github.com/nasa/Common-Metadata-Repository/releases for more information on the latest version.DEVELOPERMaintenance and Development, Earth Observing System Data and Information System, Earth Observing System,Goddard Space Flight Center, NASANASA/GSFC/EOS/EOSDIS/EMDORIGINATORPUBLISHERSERVICE PROVIDERNASA National Snow and Ice Data Center Distributed Active Archive CenterNASA NSIDC DAACNSIDC DAAC home pagehttps://nsidc.org/daacNASA Distributed Active Archive Center (DAAC) at NSIDC home page.https://cdn.earthdata.nasa.gov/umm/service/v1.4UMM-S1.4https://cmr.earthdata.nasa.gov/virtual-directory/collections/C2938661641-NSIDC_CPRDapplication/vnd.nasa.cmr.umm+jsonfalseamy.steikermmt_service_25004S2472217299-NSIDC_CPRDNSIDC_CPRD1service2022-09-20T22:05:06.185Zs3://nsidc-cumulus-prod-protected/NSIDC_CPRD_S3NOT PROVIDED1.0NASA Earthdata Cloud (AWS S3)Access data directly from the NASA Earthdata Cloud via Amazon Web Services Simple Storage Service (AWS S3). This access option is only available when working within the us-west-2 region and requires additional AWS S3 credentials.https://nsidc.org/data/user-resources/help-center/nasa-earthdata-cloud-data-access-guideVIEW RELATED INFORMATIONNASA Earthdata Cloud Data Access GuidePublicationURLhttps://data.nsidc.earthdatacloud.nasa.gov/s3credentialsVIEW RELATED INFORMATIONAWS S3 CredentialsPublicationURLUSER SERVICESNSIDC DAAC User ServicesEmailnsidc@nsidc.orgDATA ACCESS/RETRIEVALDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESThis is the most current release of this service. Last updated date is unknown.SERVICE PROVIDERNASA National Snow and Ice Data Center Distributed Active Archive CenterNASA NSIDC DAAChttps://cdn.earthdata.nasa.gov/umm/service/v1.4UMM-S1.4https://nsidc.org/data/user-resources/help-center/nasa-earthdata-cloud-data-access-guideNSIDCRelated Toolsapplication/vnd.nasa.cmr.umm+jsonfalsefritzdimmt_tool_50907TL3010466318-NSIDC_CPRDNSIDC_CPRD5tool2026-06-24T18:30:53.034Zhttps://zenodo.org/badge/latestdoi/399867529DOWNLOAD SOFTWAREhttps://earthaccess.readthedocs.io/en/stable/DistributionURLNSIDC_CPRD_EARTHACCESSDownloadable Tool0.18.0earthaccessearthaccess is a python library to search and access NASA Earth science data with just a few lines of code.https://github.com/earthaccess-dev/earthaccessVIEW RELATED INFORMATIONGitHub RepositoryPublicationURLDATA ACCESS/RETRIEVALDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESDATA SEARCHDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESPUBLISHERNSIDC DAAC User ServicesEmailnsidc@nsidc.orgPUBLISHERNASA National Snow and Ice Data Center Distributed Active Archive Centerhttps://nsidc.org/daac/NASA NSIDC DAACPUBLISHERNational Snow and Ice Data Centerhttp://nsidc.orgNSIDCDEVELOPERAlaska Satellite Facilityhttps://www.asf.alaska.edu/ASFDEVELOPERInstitute for the Study of Earth, Oceans, and Space, University of New Hampshirehttp://www.eos.unh.edu/UNH/EOSDEVELOPERAtmospheric Science Data Center, Science Directorate, Langley Research Center, NASAhttps://asdc.larc.nasa.gov/NASA/LARC/SD/ASDCMIT License
Copyright (c) 2021 Luis Lopez
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
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The above copyright notice and this permission notice shall be included in all
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.2026-05-12T00:00:00.000ZAs a condition of use, we request that you properly cite the earthaccess library to acknowledge the creators. Formal citations also make it easier for us to track the use and impact of our data and tools, and helps us report data distribution activity and tool usage metrics to funding agencies.
If you have used earthaccess in your research, please cite as:
Barrett, A., Battisto, C., Bourbeau, J., Fisher, M., Kaufman, D., Kennedy, J., Lopez, L., Lowndes, J., Scheick, J., & Steiker, A. (2024). earthaccess (Version 0.9.0) [Computer software]. https://doi.org/10.5281/zenodo.8365009
See https://github.com/nsidc/earthaccess/releases for more information on the latest version.https://cdn.earthdata.nasa.gov/umm/tool/v1.0UMM-T1.0Python3.8 or higherhttps://earthaccess.readthedocs.io/en/stable/application/vnd.nasa.cmr.umm+jsonfalsecrumlydmmt_tool_12314TL4019511337-NSIDC_CPRDNSIDC_CPRD1tool2026-02-11T17:42:34.275ZGOTO WEB TOOLhttps://nsidc.org/data/data-access-tool/DistributionURLNSIDC_CPRD_Data_Access_ToolWeb User Interface3.1.0Data Access ToolFilter files before downloading based on date, spatial area, or file name. Choose from various download options, such as Python script. Export bounding boxes as a GeoJSON.https://nsidc.org/support/how/search-filter-and-order-nsidc-dataVIEW RELATED INFORMATIONHow to filter and order from a data set web pagePublicationURLhttps://nsidc.org/data/user-resources/help-center/how-to-use-earthdata-downloadVIEW RELATED INFORMATIONHow to use Earthdata DownloadPublicationURLDATA SEARCHDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESDATA ACCESS/RETRIEVALDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESSERVICE PROVIDERNSIDC User ServicesEmailnsidc@nsidc.orgDEVELOPERPUBLISHERSERVICE PROVIDERNASA National Snow and Ice Data Center Distributed Active Archive Centerhttps://nsidc.org/daac/NASA NSIDC DAAC2025-04-16T00:00:00.000ZChromeFirefoxSafariSee https://github.com/nsidc/data-access-tool-ui/blob/main/CHANGELOG.md for more information on the latest version.https://cdn.earthdata.nasa.gov/umm/tool/v1.0UMM-T1.0https://nsidc.org/data/data-access-tool/SPL1AP/versions/2/application/vnd.nasa.cmr.umm+jsonfalsecrumlydmmt_tool_12821TL4019517520-NSIDC_CPRDNSIDC_CPRD1tool2026-02-11T17:45:02.724ZGOTO WEB TOOLhttps://search.earthdata.nasa.gov/searchDistributionURLNSIDC_CPRD_NASA_Earthdata_SearchWeb User Interface1NASA Earthdata SearchSearch and order data from all NASA DAACs using spatial and temporal filters in a map interface. Reformatting, reprojecting, and subsetting options are available for some data sets.https://nsidc.org/support/how/search-order-and-customize-nsidc-daac-data-nasa-earthdata-searchVIEW RELATED INFORMATIONHow to search, order, and customize data with NASA Earthdata SearchPublicationURLDATA VISUALIZATIONDATA ANALYSIS AND VISUALIZATIONEARTH SCIENCE SERVICESDATA SEARCHDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESDATA ACCESS/RETRIEVALDATA MANAGEMENT/DATA HANDLINGEARTH SCIENCE SERVICESSERVICE PROVIDERNSIDC DAAC User ServicesEmailnsidc@nsidc.orgSERVICE PROVIDEREarthdata Service DeskEmailsupport@earthdata.nasa.govAUTHORDEVELOPERORIGINATORPUBLISHERMaintenance and Development, Earth Observing System Data and Information System, Earth Observing System,Goddard Space Flight Center, NASAhttp://newsroom.gsfc.nasa.gov/NASA/GSFC/EOS/EOSDIS/EMDChromeFirefoxSafariThis is the most current release of this tool.https://cdn.earthdata.nasa.gov/umm/tool/v1.0UMM-T1.0https://search.earthdata.nasa.gov/search/granules?p=C2938661641-NSIDC_CPRD