Validation of Soil Moisture Data Products from the NASA SMAP Mission

Andreas Colliander, Rolf H. Reichle, Wade T. Crow, Michael H. Cosh, Fan Chen, Steven Chan, Narendra Narayan Das, Rajat Bindlish, J. Chaubell, Seungbum Kim, Qing Liu, Peggy E. Oaneill, R. Scott Dunbar, Land B. Dang, John S. Kimball, Thomas Jackson, Hala Al-Jassar, Jun Asanuma, Bimal Bhattacharya, Aaron A. BergDavid D. Bosch, Laura Bourgeau-Chavez, Todd Caldwell, Jean Christophe Calvet, Chandra Holifield Collins, Karsten H. Jensen, Stan Livingston, Ernesto Lopez-Baeza, José Martínez-Fernández, Heather McNairn, Mahta Moghaddam, Carsten Montzka, Claudia Notarnicola, Thierry Pellarin, Isabella Greimeister-Pfeil, Jouni Pulliainen, Judith Gpe Ramos Hernández, Mark Seyfried, Patrick J. Starks, Bob Su, R. Van Der Velde, Yijian Zeng, Marc Thibeault, Mariette Vreugdenhil, Jeffrey P. Walker, Mehrez Zribi, Dara Entekhabi, Simon H. Yueh

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


The National Aeronautics and Space Administration Soil Moisture Active Passive (SMAP) mission has been validating its soil moisture (SM) products since the start of data production on March 31, 2015. Prior to launch, the mission defined a set of criteria for core validation sites (CVS) that enable the testing of the key mission SM accuracy requirement (unbiased root-mean-square error <0.04 m3/m3). The validation approach also includes other ('sparse network') in situ SM measurements, satellite SM products, model-based SM products, and field experiments. Over the past six years, the SMAP SM products have been analyzed with respect to these reference data, and the analysis approaches themselves have been scrutinized in an effort to best understand the products' performance. Validation of the most recent SMAP Level 2 and 3 SM retrieval products (R17000) shows that the L-band (1.4 GHz) radiometer-based SM record continues to meet mission requirements. The products are generally consistent with SM retrievals from the European Space Agency Soil Moisture Ocean Salinity mission, although there are differences in some regions. The high-resolution (3-km) SM retrieval product, generated by combining Copernicus Sentinel-1 data with SMAP observations, performs within expectations. Currently, however, there is limited availability of 3-km CVS data to support extensive validation at this spatial scale. The most recent (version 5) SMAP Level 4 SM data assimilation product providing surface and root-zone SM with complete spatio-temporal coverage at 9-km resolution also meets performance requirements. The SMAP SM validation program will continue throughout the mission life; future plans include expanding it to forested and high-latitude regions.

Original languageEnglish
Pages (from-to)364-392
Number of pages29
JournalIEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
StatePublished - 2022


  • Core validation sites (CVS)
  • Soil Moisture Active Passive (SMAP)
  • soil moisture (SM)
  • validation


Dive into the research topics of 'Validation of Soil Moisture Data Products from the NASA SMAP Mission'. Together they form a unique fingerprint.

Cite this