{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,11]],"date-time":"2026-04-11T19:56:48Z","timestamp":1775937408040,"version":"3.50.1"},"reference-count":61,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2018,4,7]],"date-time":"2018-04-07T00:00:00Z","timestamp":1523059200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>This study evaluates the accuracy of several recent remote sensing Surface Soil Moisture (SSM) products at sites in southwestern France. The products used are Soil Moisture Active Passive \u201cSMAP\u201d (level 3: 36 km \u00d7 36 km, level 3 enhanced: 9 km \u00d7 9 km, and Level 2 SMAP\/Sentinel-1: 1 km \u00d7 1km), Advanced Scatterometer \u201cASCAT\u201d (level 2 with three spatial resolution 25 km \u00d7 25 km, 12.5 km \u00d7 12.5 km, and 1 km \u00d7 1 km), Soil Moisture and Ocean Salinity \u201cSMOS\u201d (SMOS INRA-CESBIO \u201cSMOS-IC\u201d, SMOS Near-Real-Time \u201cSMOS-NRT\u201d, SMOS Centre Aval de Traitement des Donn\u00e9es SMOS level 3 \u201cSMOS-CATDS\u201d, 25 km \u00d7 25 km) and Sentinel-1(S1) (25 km \u00d7 25 km, 9 km \u00d7 9 km, and 1 km \u00d7 1 km). The accuracy of SSM products was computed using in situ measurements of SSM observed at a depth of 5 cm. In situ measurements were obtained from the SMOSMANIA ThetaProbe (Time Domaine reflectometry) network (7 stations between 1 January 2016 and 30 June 2017) and additional field campaigns (near Montpellier city in France, between 1 January 2017 and 31 May 2017) in southwestern France. For our study sites, results showed that (i) the accuracy of the Level 2 SMAP\/Sentinel-1 was lower than that of SMAP-36 km and SMAP-9 km; (ii) the SMAP-36 km and SMAP-9 km products provide more precise SSM estimates than SMOS products (SMOS-IC, SMOS-NRT, and SMOS-CATDS), mainly due to higher sensitivity of SMOS to RFI (Radio Frequency Interference) noise; and (iii) the accuracy of SMAP-36 km and SMAP-9 km products was similar to that of ASCAT (ASCAT-25 km, ASCAT-12.5 km and ASCAT-1 km) and S1 (S1-25 km, S1-9 km, and S1-1 km) products. The accuracy of SMAP, Sentinel-1 and ASCAT SSM products calculated using the average of statistics obtained on each site is defined by a bias of about \u22123.2 vol. %, RMSD (Root Mean Square Difference) about 7.6 vol. %, ubRMSD (unbiased Root Mean Square Difference)about 5.6 vol. %, and R coefficient about 0.57. For SMOS products, the station average bias, RMSD, ubRMSD, and R coefficient were about \u221210.6 vol. %, 12.7 vol. %, 5.9 vol. %, and 0.49, respectively.<\/jats:p>","DOI":"10.3390\/rs10040569","type":"journal-article","created":{"date-parts":[[2018,4,10]],"date-time":"2018-04-10T13:06:08Z","timestamp":1523365568000},"page":"569","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":83,"title":["Evaluation of SMOS, SMAP, ASCAT and Sentinel-1 Soil Moisture Products at Sites in Southwestern France"],"prefix":"10.3390","volume":"10","author":[{"given":"Mohammad","family":"El Hajj","sequence":"first","affiliation":[{"name":"IRSTEA, University of Montpellier, TETIS, 500 rue Fran\u00e7ois Breton, 34093 Montpellier CEDEX 5, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9461-4120","authenticated-orcid":false,"given":"Nicolas","family":"Baghdadi","sequence":"additional","affiliation":[{"name":"IRSTEA, University of Montpellier, TETIS, 500 rue Fran\u00e7ois Breton, 34093 Montpellier CEDEX 5, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6141-8222","authenticated-orcid":false,"given":"Mehrez","family":"Zribi","sequence":"additional","affiliation":[{"name":"Centre d\u2019Etudes Spatiales de la BIOsph\u00e8re (CESBIO), Universit\u00e9 de Toulouse, CNES\/CNRS\/IRD\/UPS, 18 av. Edouard Belin, bpi 2801, 31401 Toulouse CEDEX 9, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3796-149X","authenticated-orcid":false,"given":"Nemesio","family":"Rodr\u00edguez-Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Centre d\u2019Etudes Spatiales de la BIOsph\u00e8re (CESBIO), Universit\u00e9 de Toulouse, CNES\/CNRS\/IRD\/UPS, 18 av. Edouard Belin, bpi 2801, 31401 Toulouse CEDEX 9, France"}]},{"given":"Jean","family":"Wigneron","sequence":"additional","affiliation":[{"name":"INRA, UMR1391 ISPA, Centre INRA Bordeaux Aquitaine, 33140 Villenave-d\u2019Ornon, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7530-6088","authenticated-orcid":false,"given":"Amen","family":"Al-Yaari","sequence":"additional","affiliation":[{"name":"INRA, UMR1391 ISPA, Centre INRA Bordeaux Aquitaine, 33140 Villenave-d\u2019Ornon, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1756-1096","authenticated-orcid":false,"given":"Ahmad","family":"Al Bitar","sequence":"additional","affiliation":[{"name":"Centre d\u2019Etudes Spatiales de la BIOsph\u00e8re (CESBIO), Universit\u00e9 de Toulouse, CNES\/CNRS\/IRD\/UPS, 18 av. Edouard Belin, bpi 2801, 31401 Toulouse CEDEX 9, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1095-2702","authenticated-orcid":false,"given":"Cl\u00e9ment","family":"Albergel","sequence":"additional","affiliation":[{"name":"CNRM UMR 3589, M\u00e9t\u00e9o-France\/CNRS, 31057 Toulouse, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6425-6492","authenticated-orcid":false,"given":"Jean-Christophe","family":"Calvet","sequence":"additional","affiliation":[{"name":"CNRM UMR 3589, M\u00e9t\u00e9o-France\/CNRS, 31057 Toulouse, France"}]}],"member":"1968","published-online":{"date-parts":[[2018,4,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.jhydrol.2005.07.003","article-title":"Evidence for intensification of the global water cycle: Review and synthesis","volume":"319","author":"Huntington","year":"2006","journal-title":"J. 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