{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,6]],"date-time":"2026-06-06T04:16:30Z","timestamp":1780719390382,"version":"3.54.1"},"reference-count":68,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2015,6,18]],"date-time":"2015-06-18T00:00:00Z","timestamp":1434585600000},"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>The current study presents an algorithm to retrieve surface Soil Moisture (SM) from multi-temporal Synthetic Aperture Radar (SAR) data. The developed algorithm is based on the Cumulative Density Function (CDF) transformation of multi-temporal RADARSAT-2 backscatter coefficient (BC) to obtain relative SM values, and then converts relative SM values into absolute SM values using soil information. The algorithm is tested in a semi-arid tropical region in South India using 30 satellite images of RADARSAT-2, SMOS L2 SM products, and 1262 SM field measurements in 50 plots spanning over 4 years. The validation with the field data showed the ability of the developed algorithm to retrieve SM with RMSE ranging from 0.02 to 0.06 m3\/m3 for the majority of plots. Comparison with the SMOS SM showed a good temporal behaviour with RMSE of approximately 0.05 m3\/m3 and a correlation coefficient of approximately 0.9. The developed model is compared and found to be better than the change detection and delta index model. The approach does not require calibration of any parameter to obtain relative SM and hence can easily be extended to any region having time series of SAR data available.<\/jats:p>","DOI":"10.3390\/rs70608128","type":"journal-article","created":{"date-parts":[[2015,6,18]],"date-time":"2015-06-18T10:08:36Z","timestamp":1434622116000},"page":"8128-8153","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":81,"title":["Retrieval and Multi-scale Validation of Soil Moisture from Multi-temporal SAR Data in a Semi-Arid Tropical Region"],"prefix":"10.3390","volume":"7","author":[{"given":"Sat","family":"Tomer","sequence":"first","affiliation":[{"name":"Centre d'Etudes Spatiales de la Biosphere (CESBIO), 31400 Toulouse, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1756-1096","authenticated-orcid":false,"given":"Ahmad","family":"Al Bitar","sequence":"additional","affiliation":[{"name":"Centre d'Etudes Spatiales de la Biosphere (CESBIO), 31400 Toulouse, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muddu","family":"Sekhar","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, Indian Institute of Science, Bangalore 560012, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6141-8222","authenticated-orcid":false,"given":"Mehrez","family":"Zribi","sequence":"additional","affiliation":[{"name":"Centre d'Etudes Spatiales de la Biosphere (CESBIO), 31400 Toulouse, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S.","family":"Bandyopadhyay","sequence":"additional","affiliation":[{"name":"Indian Space Research Organization, Bangalore 560097, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K.","family":"Sreelash","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, Indian Institute of Science, Bangalore 560012, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6964-999X","authenticated-orcid":false,"given":"A.K.","family":"Sharma","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, Indian Institute of Science, Bangalore 560012, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samuel","family":"Corgne","sequence":"additional","affiliation":[{"name":"LETG Rennes Costel, UMR 6554 CNRS, 350043 Rennes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6352-1717","authenticated-orcid":false,"given":"Yann","family":"Kerr","sequence":"additional","affiliation":[{"name":"Centre d'Etudes Spatiales de la Biosphere (CESBIO), 31400 Toulouse, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2015,6,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Lakshmi, V. (2013). Remote sensing of soil moisture. ISRN Soil Sci.","DOI":"10.1155\/2013\/424178"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Wood, E.F., Roundy, J.K., Troy, T.J., van Beek, L., Bierkens, M.F., Blyth, E., de Roo, A., D\u00f6ll, P., Ek, M., and Famiglietti, J. (2011). Hyperresolution global land surface modeling: Meeting a grand challenge for monitoring Earth\u2019s terrestrial water. Water Resour. Res.","DOI":"10.1029\/2010WR010090"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1029","DOI":"10.1002\/hyp.5520","article-title":"The role of satellite remote sensing in the prediction of ungauged basins","volume":"18","author":"Lakshmi","year":"2004","journal-title":"Hydrol. Process."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"805","DOI":"10.5589\/m04-043","article-title":"Estimating soil moisture at the watershed scale with satellite-based radar and land surface models","volume":"30","author":"Moran","year":"2004","journal-title":"Can. J. Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1545","DOI":"10.1109\/TGRS.2006.871199","article-title":"High-resolution change estimation of soil moisture using L-band radiometer and radar observations made during the SMEX02 experiments","volume":"44","author":"Narayan","year":"2006","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1109\/36.134085","article-title":"Backscattering from a randomly rough dielectric surface","volume":"30","author":"Fung","year":"1992","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"848","DOI":"10.1109\/LGRS.2013.2279893","article-title":"Influence of radar frequency on the relationship between bare surface soil moisture vertical profile and radar backscatter","volume":"11","author":"Zribi","year":"2014","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"3059","DOI":"10.1080\/01431160110115771","article-title":"Explaining temporal and spatial variation in soil moisture in a bare field using SAR imagery","volume":"24","author":"Kelly","year":"2003","journal-title":"Int. J. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2337","DOI":"10.1080\/01431160050029620","article-title":"The relation between ERS-2 SAR backscatter and soil moisture: Generalization from a humid to semi-arid transect","volume":"21","author":"Shoshany","year":"2000","journal-title":"Int. J. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1491","DOI":"10.1029\/98WR00032","article-title":"Relation between ERS-1 synthetic aperture radar data and measurements of surface roughness and moisture content of rocky soils in a semiarid rangeland","volume":"34","author":"Sano","year":"1998","journal-title":"Water Resour. Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1016\/j.rse.2013.02.027","article-title":"Soil moisture mapping using Sentinel-1 images: Algorithm and preliminary validation","volume":"134","author":"Paloscia","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1109\/JSTARS.2014.2378795","article-title":"Estimation of soil moisture in mountain areas using SVR technique applied to multiscale active radar images at C-band","volume":"8","author":"Pasolli","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_13","unstructured":"Moran, M.S., McElroy, S., Watts, J.M., and Peters-Lidar, C. (2003, January 2\u20136). Radar remote sensing for estimation of surface soil moisture at the watershed scale. Aquascalientes, Mexico."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1016\/S0034-4257(99)00036-X","article-title":"A method for estimating soil moisture from ERS scatterometer and soil data","volume":"70","author":"Wagner","year":"1999","journal-title":"Remote Sens. Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/S0168-1923(00)00189-1","article-title":"Soil moisture evaluation using multi-temporal synthetic aperture radar (SAR) in semiarid rangeland","volume":"105","author":"Moran","year":"2000","journal-title":"Agric. For. Meteorol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Thoma, D., Moran, M., Bryant, R., Rahman, M., Holifield-Collins, C., Skirvin, S., Sano, E., and Slocum, K. (2006). Comparison of four models to determine surface soil moisture from C-band radar imagery in a sparsely vegetated semiarid landscape. Water Resour. Res., 42.","DOI":"10.1029\/2004WR003905"},{"key":"ref_17","unstructured":"Ulaby, F.T., Moore, R.K., and Fung, A.K. (1986). Microwave Remote Sensing Active and Passive-Volume III: From Theory to Applications, Addison-Wesley."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3492","DOI":"10.1109\/TGRS.2014.2377714","article-title":"Soil moisture retrieval using L-band radar observations","volume":"53","author":"Narvekar","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1791","DOI":"10.1109\/TGRS.2012.2205264","article-title":"Incidence angle normalization of radar backscatter data","volume":"51","author":"Mladenova","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1127\/0941-2948\/2006\/0130","article-title":"World map of the K\u00f6ppen-Geiger climate classification updated","volume":"15","author":"Kottek","year":"2006","journal-title":"Meteorol. Z."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1016\/j.catena.2006.10.013","article-title":"Using a structural approach to identify relationships between soil and erosion in a semi-humid forested area, South India","volume":"70","author":"Parate","year":"2007","journal-title":"Catena"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.jhydrol.2012.06.012","article-title":"Parameter estimation of a two-horizon soil profile by combining crop canopy and surface soil moisture observations using GLUE","volume":"456","author":"Sreelash","year":"2012","journal-title":"J. Hydrol."},{"key":"ref_23","first-page":"189","article-title":"Improved modeling of groundwater recharge in agricultural watersheds using a combination of crop model and remote sensing","volume":"93","author":"Sreelash","year":"2013","journal-title":"J. Indian Inst. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1007\/BF02990776","article-title":"Extraction and validation of Cartosat-1 DEM","volume":"35","author":"Ahmed","year":"2007","journal-title":"J. Indian Soc. Remote Sens."},{"key":"ref_25","unstructured":"Karnataka State Remote Sensing Application Centre (2007). Report on State Natural Resources Information System, unpublished."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1384","DOI":"10.1109\/TGRS.2012.2184548","article-title":"The SMOS soil moisture retrieval algorithm","volume":"50","author":"Kerr","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/S0022-1694(01)00466-8","article-title":"rosetta: A computer program for estimating soil hydraulic parameters with hierarchical pedotransfer functions","volume":"251","author":"Schaap","year":"2001","journal-title":"J. Hydrol."},{"key":"ref_28","unstructured":"Ulaby, F.T., Moore, R.K., and Fung, A.K. (1982). Microwave Remote Sensing Active and Passive-Volume II: Radar Remote Sensing and Surface Scattering and Enission Theory, Addison-Wesley."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"151","DOI":"10.5194\/hess-15-151-2011","article-title":"Effective roughness modelling as a tool for soil moisture retrieval from C-and L-band SAR","volume":"15","author":"Lievens","year":"2011","journal-title":"Hydrol. Earth Syst. Sci."},{"key":"ref_30","first-page":"24","article-title":"Performance comparison of median and wiener filter in image de-noising","volume":"12","author":"Kumar","year":"2010","journal-title":"Int. J. Comput. Appl."},{"key":"ref_31","unstructured":"Engdahl, M., Minchella, A., Marinkovic, P., Veci, L., and Lu, J. Nest: An esa open source toolbox for scientific exploitation of sar data. Munich, Germany."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"6827","DOI":"10.1080\/01431160802270123","article-title":"Biophysical estimation in tropical forests using JERS-1 SAR and VNIR imagery. II. Aboveground woody biomass","volume":"29","author":"Wang","year":"2008","journal-title":"Int. J. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Narvekar, P.S., Entekhabhi, D., Kim, S., and Njoku, E. (2013, January 21\u201326). A robust algorithm for soil moisture retrieval from the Soil Moisture Active Passive mission RADAR observation. Melbourne, VIC, Australia.","DOI":"10.1109\/IGARSS.2013.6721088"},{"key":"ref_34","first-page":"916","article-title":"Measuring soil moisture with imaging radars","volume":"33","author":"Dubois","year":"1995","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"3547","DOI":"10.1080\/01431160601009680","article-title":"Soil moisture mapping based on ASAR\/ENVISAT radar data over a Sahelian region","volume":"28","author":"Zribi","year":"2007","journal-title":"Int. J. Remote Sens."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1109\/TPWRS.2008.2004728","article-title":"Using copulas for modeling stochastic dependence in power system uncertainty analysis","volume":"24","author":"Papaefthymiou","year":"2009","journal-title":"IEEE Trans. Power Syst."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.geoderma.2007.03.011","article-title":"A single layer soil water balance model for estimating deep drainage (potential recharge): An application to cropped land in semi-arid North-East Nigeria","volume":"140","author":"Eilers","year":"2007","journal-title":"Geoderma"},{"key":"ref_38","unstructured":"Silverman, B.W. (1986). Density Estimation for Statistics and Data Analysis, CRC Press."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"425","DOI":"10.5194\/hess-15-425-2011","article-title":"Developing an improved soil moisture dataset by blending passive and active microwave satellite-based retrievals","volume":"15","author":"Liu","year":"2011","journal-title":"Hydrol. Earth Syst. Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1572","DOI":"10.1109\/TGRS.2012.2186581","article-title":"Evaluation of SMOS soil moisture products over continental US using the SCAN\/SNOTEL network","volume":"50","author":"Leroux","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"2498","DOI":"10.1109\/TGRS.2010.2040746","article-title":"Validation of the ASAR global monitoring mode soil moisture product using the NAFE\u201905 data set","volume":"48","author":"Mladenova","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1109\/TGRS.2008.2004711","article-title":"Using ENVISAT ASAR global mode data for surface soil moisture retrieval over Oklahoma, USA","volume":"47","author":"Pathe","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"635","DOI":"10.1109\/LGRS.2009.2012727","article-title":"Assessing the SMOS soil moisture retrieval parameters with high-resolution NAFE\u201906 data","volume":"6","author":"Merlin","year":"2009","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"286","DOI":"10.1109\/TGE.1978.294586","article-title":"Microwave backscatter dependence on surface roughness, soil moisture and soil texture: Part I - bare soil","volume":"GE-16","author":"Ulaby","year":"1978","journal-title":"IEEE Trans. Geosci. Electron."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1016\/0034-4257(82)90052-9","article-title":"C-band radar for determining surface soil moisture","volume":"12","author":"Bernard","year":"1982","journal-title":"Remote Sens. Environ."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/0034-4257(95)00212-X","article-title":"Taking into account vegetation effects to estimate soil moisture from C-band radar measurements","volume":"56","author":"Taconet","year":"1996","journal-title":"Remote Sens. Environ."},{"key":"ref_47","first-page":"1196","article-title":"Assimilation of remote sensing and hydrological data using adaptive filtering techniques for watershed modeling","volume":"97","author":"Sekhar","year":"2009","journal-title":"Curr. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"564","DOI":"10.1109\/LGRS.2011.2174772","article-title":"Radar vegetation index for estimating the vegetation water content of rice and soybean","volume":"9","author":"Kim","year":"2012","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2519","DOI":"10.1109\/TGRS.2009.2014944","article-title":"A time-series approach to estimate soil moisture using polarimetric radar data","volume":"47","author":"Kim","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/S0034-4257(02)00069-X","article-title":"A new empirical model to retrieve soil moisture and roughness from C-band radar data","volume":"84","author":"Zribi","year":"2003","journal-title":"Remote Sens. Environ."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"463","DOI":"10.3390\/s90100463","article-title":"Influence of surface roughness spatial variability and temporal dynamics on the retrieval of soil moisture from SAR observations","volume":"9","author":"Verhoest","year":"2009","journal-title":"Sensors"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1065","DOI":"10.1109\/36.602548","article-title":"First order surface roughness correction of active microwave observations for estimating soil moisture","volume":"35","author":"Jackson","year":"1997","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1016\/j.rse.2013.08.030","article-title":"Estimation of soil surface roughness of agricultural soils using airborne LiDAR","volume":"140","author":"Turner","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.rse.2010.07.011","article-title":"Soil moisture retrieval over agricultural fields from multi-polarized and multi-angular RADARSAT-2 SAR data","volume":"115","author":"Gherboudj","year":"2011","journal-title":"Remote Sens. Environ."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"345","DOI":"10.5194\/hess-15-345-2011","article-title":"Soil surface moisture estimation over a semi-arid region using ENVISAT ASAR radar data for soil evaporation evaluation","volume":"15","author":"Zribi","year":"2011","journal-title":"Hydrol. Earth Syst. Sci. Discuss."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"256","DOI":"10.3390\/s8010256","article-title":"Soil moisture profile effect on radar signal measurement","volume":"8","author":"Zribi","year":"2008","journal-title":"Sensors"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1109\/TGRS.2005.862248","article-title":"Assessment of the operational applicability of RADARSAT-1 data for surface soil moisture estimation","volume":"44","author":"Verhoest","year":"2006","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1109\/TGRS.1986.289585","article-title":"Active microwave soil moisture research","volume":"GE-24","author":"Dobson","year":"1986","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"396","DOI":"10.1016\/j.rse.2013.07.021","article-title":"Comparison between SMOS Vegetation Optical Depth products and MODIS vegetation indices over crop zones of the USA","volume":"140","author":"Lawrence","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"3858","DOI":"10.1109\/JSTARS.2014.2321027","article-title":"SMOS retrieval results over forests: Comparisons with independent measurements","volume":"7","author":"Rahmoune","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"1729","DOI":"10.1109\/36.942551","article-title":"Soil moisture retrieval from space: The Soil Moisture and Ocean Salinity (SMOS) mission","volume":"39","author":"Kerr","year":"2001","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/0034-4257(95)00133-L","article-title":"Soil moisture and temperature profile effects on microwave emission at low frequencies","volume":"54","author":"Raju","year":"1995","journal-title":"Remote Sens. Environ."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"995","DOI":"10.1016\/j.rse.2009.12.011","article-title":"Effective soil moisture sampling depth of L-band radiometry: A case study","volume":"114","author":"Escorihuela","year":"2010","journal-title":"Remote Sens. Environ."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"864","DOI":"10.1175\/JHM463.1","article-title":"Evaluation of AMSR-E-derived soil moisture retrievals using ground-based and PSR airborne data during SMEX02","volume":"6","author":"McCabe","year":"2005","journal-title":"J. Hydrometeorol."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"2096","DOI":"10.1016\/j.rse.2011.04.011","article-title":"Validation of AMSR-E soil moisture using L-band airborne radiometer data from National Airborne Field Experiment 2006","volume":"115","author":"Mladenova","year":"2011","journal-title":"Remote Sens. Environ."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"4997","DOI":"10.1002\/2014GL060017","article-title":"The impact of vertical measurement depth on the information content of soil moisture times series data","volume":"41","author":"Qiu","year":"2014","journal-title":"Geophys. Res. Lett."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"1","DOI":"10.2166\/nh.2007.029","article-title":"Operational readiness of microwave remote sensing of soil moisture for hydrologic applications","volume":"38","author":"Bizzarri","year":"2007","journal-title":"Nord. Hydrol."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/j.rse.2014.04.006","article-title":"Global-scale evaluation of two satellite-based passive microwave soil moisture datasets (SMOS and AMSR-E) with respect to Land Data Assimilation System estimates","volume":"149","author":"Wigneron","year":"2014","journal-title":"Remote Sens. Environ."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/7\/6\/8128\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:48:06Z","timestamp":1760215686000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/7\/6\/8128"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,6,18]]},"references-count":68,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2015,6]]}},"alternative-id":["rs70608128"],"URL":"https:\/\/doi.org\/10.3390\/rs70608128","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,6,18]]}}}