2026-09-19T21:01:19Zhttp://nsidc.org/api/dataset/metadata/oai
oai:nsidc.org/SPL2SMAP_S.0022026-08-19T22:16:37Zcumulusecsretirednasa_nsidc_daac
SPL2SMAP_S.002SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil MoistureDas, N., Entekhabi, D., Dunbar, R. S., Kim, S., Yueh, S., Colliander, A., O'Neill, P. E., Jackson, T., Jagdhuber, T., Chen, F., Crow, W. T., Walker, J., Berg, A., Bosch, D., Caldwell, T. & Cosh, M.SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture2018-06-18Boulder, Colorado USANASA NSIDC DAAC: NASA National Snow and Ice Data Center Distributed Active Archive Center2false10.5067/KE1CSVXMI95Yhttps://nsidc.org/sites/default/files/spl2smap_s-v002-userguide.pdfSPL2SMAP_SDas, N., Entekhabi, D., Dunbar, S., Chaubell, J., Colliander, A., Yueh, S., Jagdhuber, T., Chen, F., Crow, W. T., O'Neill, P. E., Walker, J., Berg, A., Bosch, D., Caldwell, T., Cosh, M., Holifield -Collins, C., Lopez-Baeza, E. & Thibeault, M.2019The SMAP and Copernicus Sentinel 1A/B microwave active-passive high resolution surface soil moisture productRemote Sensing of Environment233111380<a href="https://doi.org/10.1016/j.rse.2019.111380">https://doi.org/10.1016/j.rse.2019.111380</a>Literature CitationTechnical ContactNSIDCUser Servicesnsidc@nsidc.org1-303-492-61991-303-492-2468
CIRES, 449 UCB
University of Colorado
BoulderCO80309-0449USAEARTH SCIENCELAND SURFACESOILSSOIL MOISTURE/WATER CONTENT Climatology/Meteorology/AtmosphereGeoscientific InformationEASE-Grid SM-projectSMAP-projectSMAP-project-L2C-SARC-Band Synthetic Aperture RadarSMAP L-BAND RADIOMETERSMAP L-Band RadiometerSENTINEL-1ASENTINEL-1ASENTINEL-1BSENTINEL-1BSMAPSoil Moisture Active and Passive Observatory2015-03-312020-08-26deprecated-6060-180180CONTINENTAFRICACONTINENTASIAGEOGRAPHIC REGIONOCEANIACONTINENTEUROPECONTINENTSOUTH AMERICACONTINENTNORTH AMERICA3 km3 km30 secondSMAP products provide multiple means to assess quality. Each product contains bit flags, uncertainty measures, and file-level metadata that provide quality information. For information regarding the specific bit flags, uncertainty measures, and file-level metadata contained in this product, refer to the Data Fields and Metadata Fields documents. Each HDF5 file contains metadata with Quality Assessment (QA) metadata flags that are set by the Science Data Processing System (SDS) at the JPL prior to delivery to NSIDC. A separate metadata file with an .xml file extension is also delivered to NSIDC with the HDF5 file; it contains the same information as the HDF5 file-level metadata. If a product does not fail QA, it is ready to be used for higher-level processing, browse generation, active science QA, archive, and distribution. If a product fails QA, it is never delivered to NSIDC DAAC.As a condition of using these data, you must cite the use of this data set using the recommended citation. For more information, see the Use and Copyright page at https://nsidc.org/about/use_copyright.html.These data are offered free of charge. You may use these data freely, provided that you cite NSIDC DAAC as the source, and provide an acknowledgment in any published papers.EnglishNASA/JPL/SMAPNASA NSIDC DAACNASA National Snow and Ice Data Center Distributed Active Archive Centerhttps://nsidc.org/daacData Center ContactNSIDCUser Servicesnsidc@nsidc.org1-303-492-6199
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
BoulderCO80309-0449USAHTTPSHDF5Bolten, J., V. Lakshmi, and E. Njoku. 2003. Soil moisture retrieval using the passive/active L- and S-band radar/radiometer. IEEE Trans. Geosci. Rem. Sens., 41:2792-2801. Brodzik, M. J., B. Billingsley, T. Haran, B. Raup, and M. H. Savoie. 2012. EASE-Grid 2.0: Incremental but significant improvements for Earth-gridded data sets. ISPRS Int. J. Geo-Inf. 1(1):32-45. http://dx.doi.org/10.3390/ijgi1010032. Brodzik, M. J., B. Billingsley, T. Haran, B. Raup, and M. H. Savoie. 2014. Correction: Brodzik, M. J. et al. EASE-Grid 2.0: Incremental but significant improvements for Earth-gridded data sets. ISPRS Int. J. Geo-Inf 2012. 1(1):32-45 ISPRS Int. J. Geo-Inf. 3(3):1154-1156. http://dx.doi.org/10.3390/ijgi3031154. Das, N. N., D. Entekhabi, S. Dunbar, E. G. Njoku, and S. Yueh. 2016. Uncertainty estimates in the SMAP combined active-passive downscaled brightness temperature. IEEE Transactions on Geoscience and Remote Sensing. 54(2):640-650, http://dx.doi.org/10.1109/TGRS.2015.2450694.  Das, N. N., and R. S. Dunbar. 2015. SMAP Level 2 Active/Passive Soil Moisture (L2_SM_AP) Product Specification Document. SMAP Project, JPL D-72548, Jet Propulsion Laboratory, Pasadena, CA. (SMAP L2_SM_AP PSD_10312015.pdf, 3 MB) Das, N. N., and R. S. Dunbar. 2017. Level 2 SMAP/Sentinel Active/Passive Soil Moisture Product Specification Document. SMAP Project, JPL D-56548, Jet Propulsion Laboratory, Pasadena, CA. (SMAP L2_SM_SP PSD_11-01-2017_latest.pdf , 1.02 MB) Das, N. N., D. Entekhabi, E. G. Njoku, J. Johnston, J. C. Shi, and A. Colliander. 2014. Tests of the SMAP combined radar and radiometer brightness temperature disaggregation algorithm using airborne field campaign observations. IEEE-TGARS. 52:2018–2028. Das, N. N., D. Entekhabi, and E. G. Njoku, 2011. An algorithm for merging SMAP radiometer and radar data for high resolution soil moisture retrieval. IEEE-TGARS. 9: 1504-1512. Das, N. N., et al. 2015. Soil Moisture Active Passive (SMAP) project calibration and validation for the L2/3_SM_AP beta-release data products. SMAP Project, JPL D-93984. Jet Propulsion Laboratory, Pasadena, CA. (SMAP-AP_Assessment_Report_Final.pdf, 4 MB) Das, N. N., D. Entekhabi, S. Dunbar, S. Kim, S. Yueh, A. Colliander, T. J. Jackson, P. E. O’Neill, M. Cosh, T. Caldwell, J. Walker, A. Berg, T. Rowlandson, J. Martínez-Fernández, Á. González-Zamora, P. Starks, C. Holifield-Collins, J. Prueger, and E. Lopez-Baeza. 2017. Calibration and validation for the L2_SM_SP beta release data products, SMAP Project, JPL D-56549, Jet Propulsion Laboratory, Pasadena, CA. (SMAPSPBetaReleaseAssessmentReport_11-01-2017_final.pdf, 6.3 MB) Entekhabi, 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. Entekhabi, D., N. Das, E. Njoku, J. Johnson, and J. Shi. 2014. SMAP Algorithm Theoretical Basis Document: L2 & L3 radar/radiometer soil moisture (active/passive) data products. SMAP Project, JPL D-66481. Jet Propulsion Laboratory, Pasadena, CA. (277_L2_3_SM_AP_RevA_web.pdf, 16.6 MB) Jagdhuber, T., M. Bauer, M. Link, N. N. Das, and D. Entekhabi. 2017. Retrieval of active-passive microwave covariation using the SMAP and Sentinel-1 Data. IEEE Transactions on Geoscience and Remote Sensing, submitted.This Level-2 (L2) soil moisture product provides estimates of land surface conditions retrieved by both the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes and the Sentinel-1A and -1B radar. SMAP L-band brightness temperatures and Copernicus Sentinel-1 C-band backscatter coefficients are used to derive soil moisture data, which are then resampled to an Earth-fixed, cylindrical 3 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0). <b>Note:</b> These data are Beta-release quality, meaning that they have not undergone full validation and may still contain significant errors.VIEW RELATED INFORMATIONhttps://nsidc.org/sites/default/files/spl2smap_s-v002-userguide.pdfSMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture, Version 2 User GuideGET DATAhttps://nsidc.org/data/data-access-tool/SPL2SMAP_S/versions/2/Data Access ToolCEOS IDN DIFVERSION 9.92018-06-182026-08-19NSIDCVersion Summary<p>Changes to this version include:</p> <ul> <li>Implemented a new method of identifying and eliminating spurious sigma0 values in Sentinel-1A/B Level-1 sigma0 data using a hybrid approach that combines a median filter with thresholding. As a result, fewer spurious sigma0 values (mainly due to small man-made structures) bias the aggregated 1 km data.</li> <li>Replaced the previous 3 km resolution urban fraction map with a new 1 km map.</li> <li>Adjusted the thresholds used with the new 1 km urban fraction map to: 0.25 (no flag), 0.25 – 0.5 (flagged, retrieval performed), and 0.5 (masked, no retrieval). These are provided in bit 3 of the surface_flag data field.</li> <li>Adjusted the tau-omega parameters to be consistent with the values used in SPL2SMP/SPL2SMP_E algorithm.</li> <li>Implemented minor bug fix to the SMAP and Sentinel-1 overlap computation code.</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 VersionR16010<ul>Changed with Version 2 update. Changes to this version include: <li>Implemented a new method of identifying and eliminating spurious sigma0 values in Sentinel-1A/B Level-1 sigma0 data using a hybrid approach that combines a median filter with thresholding. As a result, fewer spurious sigma0 values (mainly due to small man-made structures) bias the aggregated 1 km data.</li> <li>Replaced the previous 3 km resolution urban fraction map with a new 1 km map.</li> <li>Adjusted the thresholds used with the new 1 km urban fraction map to: 0.25 (no flag), 0.25 – 0.5 (flagged, retrieval performed), and 0.5 (masked, no retrieval). These are provided in bit 3 of the surface_flag data field.</li> <li>Adjusted the tau-omega parameters to be consistent with the values used in SPL2SMP/SPL2SMP_E algorithm.</li> <li>Implemented minor bug fix to the SMAP and Sentinel-1 overlap computation code.</li></ul>2015-03-312018-11-061R16020No science change. CRID incremented to coincide with TB and half-orbit correction for SPL3SMP, SPL2SMP_E, and SPL3SMP_E products.2018-11-042018-12-302R16022No science change. CRID incremented to coincide with an update to the radiometer reflector ancillary file for January through December 2019.2018-12-192019-08-123R16510No science change. CRID incremented to coincide with the release of SPL2SMP V6, SPL2SMP_E V3, SPL3SMP V6, and SPL3SMP_E V3.2019-04-092019-12-204R16515No science change. CRID incremented to coincide with an update to the radiometer reflector ancillary file for January through December 2020.2017-01-022020-08-265NSIDCSpatial Reference SystemsEPSG:6933WGS 84 / NSIDC EASE-Grid 2.0 GlobalNSIDCLevel of ServiceNo Data AccessNSIDCFull Dataset CitationDas, N., Entekhabi, D., Dunbar, R. S., Kim, S., Yueh, S., Colliander, A., O'Neill, P. E., Jackson, T., Jagdhuber, T., Chen, F., Crow, W. T., Walker, J., Berg, A., Bosch, D., Caldwell, T. & Cosh, M. (2018). <i>SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture</i>. (SPL2SMAP_S, 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/KE1CSVXMI95Y">https://doi.org/10.5067/KE1CSVXMI95Y</a>. [<i><describe subset used if applicable></i>].NSIDCRetiredtrue