Evaluation of SMOS soil moisture products over continental U.S. Using the SCAN/SNOTEL network

Ahmad Al Bitar, Delphine Leroux, Yann H. Kerr, Olivier Merlin, Philippe Richaume, Alok Sahoo, Eric F. Wood

Research output: Contribution to journalArticlepeer-review

225 Scopus citations


The Soil Moisture and Ocean Salinity (SMOS) satellite has opened the era of soil moisture products from passive L-band observations. In this paper, validation of SMOS products over continental U.S. is done by using the Soil Climate Analysis Network (SCAN)/SNOwpack TELemetry (SNOTEL) soil moisture monitoring stations. The SMOS operational products and the SMOS reprocessing products are both used and compared over year 2010. First, a direct node-to-site comparison is performed by taking advantage of the oversampling of the SMOS product grid. The comparison is performed over several adjacent nodes to site, and several representative couples of site-node are identified. The impact of forest fraction is shown through the analysis of different cases across the U.S. Also, the impact of water fraction is shown through two examples in Florida and in Utah close to Great Salt Lake. A radiometric aggregation approach based on the antenna footprint and spatial description is used. A global comparison of the SCAN/SNOTEL versus SMOS is made. Statistics show an underestimation of the soil moisture from SMOS compared to the SCAN/SNOTEL local measurements. The results suggest that SMOS meets the mission requirement of 0.04 m 3m 3 over specific nominal cases, but differences are observed over many sites and need to be addressed.

Original languageEnglish (US)
Article number6178795
Pages (from-to)1572-1586
Number of pages15
JournalIEEE Transactions on Geoscience and Remote Sensing
Issue number5 PART 1
StatePublished - May 2012

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering
  • General Earth and Planetary Sciences


  • L-band
  • SNOwpack TELemetry (SNOTEL)
  • Soil Climate Analysis Network (SCAN)
  • Soil Moisture and Ocean Salinity (SMOS)
  • microwave
  • soil moisture
  • validation


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