{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T13:49:49Z","timestamp":1789480189311,"version":"build-2803163510"},"reference-count":38,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2018,2,16]],"date-time":"2018-02-16T00:00:00Z","timestamp":1518739200000},"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>Organic soils play a key role in global warming because they store large amount of soil carbon which might be degraded with changing soil temperatures or soil water contents. There is thus a strong need to monitor these soils and, in particular, their hydrological characteristics using, for instance, space-borne L-band brightness temperature observations. However, there are still open issues with respect to soil moisture retrieval techniques over organic soils. In view of this, organic soil blocks with their vegetation cover were collected from a heathland in the Skjern River catchment in western Denmark and then transported to a remote sensing field laboratory in Germany where their structure was reconstituted. The controlled conditions at this field laboratory made it possible to perform tower-based L-band radiometer measurements of the soils over a period of two months. Brightness temperature data were inverted using a radiative transfer (RT) model for estimating the time variations in the soil dielectric permittivity and the vegetation optical depth. In addition, the effective vegetation scattering albedo parameter of the RT model was retrieved based on a two-step inversion approach. The remote estimations of the dielectric permittivity were compared to in situ measurements. The results indicated that the radiometer-derived dielectric permittivities were significantly correlated with the in situ measurements, but their values were systematically lower compared to the in situ ones. This could be explained by the difference between the operating frequency of the L-band radiometer (1.4 GHz) and that of the in situ sensors (70 MHz). The effective vegetation scattering albedo parameter was found to be polarization dependent. While the scattering effect within the vegetation could be neglected at horizontal polarization, it was found to be important at vertical polarization. The vegetation optical depth estimated values over time oscillated between 0.10 and 0.19 with a mean value of 0.13. This study provides further insights into the characterization of the L-band brightness temperature signatures of organic soil surface layers and, in particular, into the parametrization of the RT model for these specific soils. Therefore, the results of this study are expected to improve the performance of space-borne remote sensing soil moisture products over areas dominated by organic soils.<\/jats:p>","DOI":"10.3390\/rs10020304","type":"journal-article","created":{"date-parts":[[2018,2,20]],"date-time":"2018-02-20T03:54:22Z","timestamp":1519098862000},"page":"304","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Passive L-Band Microwave Remote Sensing of Organic Soil Surface Layers: A Tower-Based Experiment"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8562-2073","authenticated-orcid":false,"given":"Fran\u00e7ois","family":"Jonard","sequence":"first","affiliation":[{"name":"Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum J\u00fclich GmbH, 52428 J\u00fclich, Germany"},{"name":"Earth and Life Institute, Universit\u00e9 catholique de Louvain, 1348 Louvain-la-Neuve, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Simone","family":"Bircher","sequence":"additional","affiliation":[{"name":"CESBIO, Universit\u00e9 de Toulouse, CNES\/CNRS\/IRD\/UPS, 31400 Toulouse, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7044-7014","authenticated-orcid":false,"given":"Fran\u00e7ois","family":"Demontoux","sequence":"additional","affiliation":[{"name":"IMS Laboratory, Universit\u00e9 de Bordeaux, 33607 Pessac, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lutz","family":"Weiherm\u00fcller","sequence":"additional","affiliation":[{"name":"Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum J\u00fclich GmbH, 52428 J\u00fclich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9651-1291","authenticated-orcid":false,"given":"Stephen","family":"Razafindratsima","sequence":"additional","affiliation":[{"name":"IMS Laboratory, Universit\u00e9 de Bordeaux, 33607 Pessac, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jean-Pierre","family":"Wigneron","sequence":"additional","affiliation":[{"name":"INRA, Centre INRA Bordeaux Aquitaine, URM1391 ISPA, 33140 Villenave d\u2019Ornon, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8051-8517","authenticated-orcid":false,"given":"Harry","family":"Vereecken","sequence":"additional","affiliation":[{"name":"Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum J\u00fclich GmbH, 52428 J\u00fclich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,2,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1618","DOI":"10.1126\/science.304.5677.1618","article-title":"Defrosting the carbon freezer of the north","volume":"304","author":"Stokstad","year":"2004","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"701","DOI":"10.1641\/B580807","article-title":"Vulnerability of permafrost carbon to climate change: Implications for the global carbon cycle","volume":"58","author":"Schuur","year":"2008","journal-title":"Bioscience"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1038\/480032a","article-title":"High risk of permafrost thaw","volume":"480","author":"Schuur","year":"2011","journal-title":"Nature"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1038\/nature04514","article-title":"Temperature sensitivity of soil carbon decomposition and feedbacks to climate change","volume":"440","author":"Davidson","year":"2006","journal-title":"Nature"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1052","DOI":"10.1007\/s11430-012-4444-x","article-title":"Progresses on microwave remote sensing of land surface parameters","volume":"55","author":"Shi","year":"2012","journal-title":"Sci. China Earth Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"666","DOI":"10.1109\/JPROC.2010.2043032","article-title":"The SMOS mission: New Tool for Monitoring Key Elements of the Global Water Cycle","volume":"98","author":"Kerr","year":"2010","journal-title":"Proc. IEEE"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"5401","DOI":"10.1109\/JSTARS.2015.2427159","article-title":"Status of Aquarius\/SAC-D and Aquarius Salinity Retrievals","volume":"8","author":"Dinnat","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1109\/JPROC.2010.2043918","article-title":"The Soil Moisture Active Passive (SMAP) Mission","volume":"98","author":"Entekhabi","year":"2010","journal-title":"Proc. IEEE"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1016\/j.rse.2017.06.037","article-title":"L-band vegetation optical depth and effective scattering albedo estimation from SMAP","volume":"198","author":"Konings","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Vereecken, H., Weiherm\u00fcller, L., Jonard, F., and Montzka, C. (2012). Characterization of crop canopies and water stress related phenomena using microwave remote sensing methods: A review. Vadose Zone J., 11.","DOI":"10.2136\/vzj2011.0138ra"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.rse.2016.04.006","article-title":"Global-scale surface roughness effects at L-band as estimated from SMOS observations","volume":"181","author":"Parrens","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"238","DOI":"10.1016\/j.rse.2017.01.024","article-title":"Modelling the passive microwave signature from land surfaces: A review of recent results and application to the L-band SMOS & SMAP soil moisture retrieval algorithms","volume":"192","author":"Wigneron","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_13","unstructured":"Bircher, S., Kerr, Y.H., and Wigneron, J.-P. (2015). SMOSHiLat\u2014Microwave L-Band Emissions from Organic-Rich Soils in the Northern Cold Climate Zone and Their Impact on the SMOS Soil Moisture Product. Support to Science Element\u2014Changing Earth Science Network, ESA-ESRIN."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"M\u00e4tzler, C. (2006). Thermal Microwave Radiation: Applications for Remote Sensing, The Institution of Engeneering and Technology.","DOI":"10.1049\/PBEW052E"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"11229","DOI":"10.1029\/JC087iC13p11229","article-title":"A model for microwave emission from vegetation-covered fields","volume":"87","author":"Mo","year":"1982","journal-title":"J. Geophys. Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1109\/TGRS.1985.289498","article-title":"Microwave dielectric behavior of wet soil\u2014Part II: Dielectric mixing models","volume":"23","author":"Dobson","year":"1985","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2059","DOI":"10.1109\/TGRS.2008.2011631","article-title":"Physically and Mineralogically Based Spectroscopic Dielectric Model for Moist Soils","volume":"47","author":"Mironov","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1109\/TGRS.1980.350304","article-title":"An empirical-model for the complex dielectric permittivity of soils as a function of water-content","volume":"18","author":"Wang","year":"1980","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Bircher, S., Demontoux, F., Razafindratsima, S., Zakharova, E., Drusch, M., Wigneron, J.P., and Kerr, Y.H. (2016). L-Band Relative Permittivity of Organic Soil Surface Layers\u2014A New Dataset of Resonant Cavity Measurements and Model Evaluation. Remote Sens., 8.","DOI":"10.3390\/rs8121024"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Jin, M., Zheng, X., Jiang, T., Li, X., Li, X.-J., and Zhao, K. (2017). Evaluation and Improvement of SMOS and SMAP Soil Moisture Products for Soils with High Organic Matter over a Forested Area in Northeast China. Remote Sens., 9.","DOI":"10.3390\/rs9040387"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.pce.2015.02.011","article-title":"A temperature-dependent multi-relaxation spectroscopic dielectric model for thawed and frozen organic soil at 0.05\u201315 GHz","volume":"83\u201384","author":"Mironov","year":"2015","journal-title":"Phys. Chem. Earth"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"4470","DOI":"10.1109\/JSTARS.2015.2442295","article-title":"A Temperature-Dependent Dielectric Model for Thawed and Frozen Organic Soil at 1.4 GHz","volume":"8","author":"Mironov","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3095","DOI":"10.1109\/TGRS.2014.2368831","article-title":"Estimation of hydraulic properties of a sandy soil using ground-based active and passive microwave remote sensing","volume":"53","author":"Jonard","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"109","DOI":"10.5194\/gi-5-109-2016","article-title":"Soil moisture sensor calibration for organic soil surface layers","volume":"5","author":"Bircher","year":"2016","journal-title":"Geosci. Instrum. Methods Data Syst."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1016\/j.rse.2012.10.021","article-title":"Quantifying scattering albedo in microwave emission of vegetated terrain","volume":"129","author":"Kurum","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"5277","DOI":"10.1029\/JC086iC06p05277","article-title":"Remote-sensing of soil-moisture content over bare field at 1.4 GHz frequency","volume":"86","author":"Wang","year":"1981","journal-title":"J. Geophys. Res."},{"key":"ref_27","first-page":"27","article-title":"A new calibration of the effective scattering albedo and soil roughness parameters in the SMOS SM retrieval algorithm","volume":"62","author":"Wigneron","year":"2017","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"639","DOI":"10.1016\/j.rse.2006.10.014","article-title":"L-band Microwave Emission of the Biosphere (L-MEB) Model: Description and calibration against experimental data sets over crop fields","volume":"107","author":"Wigneron","year":"2007","journal-title":"Remote Sens. Environ."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1023\/A:1008382309369","article-title":"Global optimization by multilevel coordinate search","volume":"14","author":"Huyer","year":"1999","journal-title":"J. Glob. Optim."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2555","DOI":"10.1109\/TGRS.2004.834800","article-title":"Modeling of ground-penetrating radar for accurate characterization of subsurface electric properties","volume":"42","author":"Lambot","year":"2004","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"H1","DOI":"10.1190\/geo2011-0054.1","article-title":"Accounting for soil surface roughness in the inversion of ultrawideband off-ground GPR signal for soil moisture retrieval","volume":"77","author":"Jonard","year":"2012","journal-title":"Geophysics"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1767","DOI":"10.1081\/DRT-200025642","article-title":"Accurate determination of moisture content of organic soils using the oven drying method","volume":"22","year":"2004","journal-title":"Dry. Technol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1016\/j.rse.2005.12.004","article-title":"Impact of rain interception by vegetation and mulch on the L-band emission of natural grass","volume":"101","author":"Saleh","year":"2006","journal-title":"Remote Sens. Environ."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"5699","DOI":"10.1029\/JC084iC09p05699","article-title":"Effect of surface-roughness on the microwave emision from soils","volume":"84","author":"Choudhury","year":"1979","journal-title":"J. Geophys. Res."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.rse.2006.12.002","article-title":"Estimates of surface soil moisture under grass covers using L-band radiometry","volume":"109","author":"Saleh","year":"2007","journal-title":"Remote Sens. Environ."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Bobrov, P.P., Mironov, V.L., Kondratyeva, O.V., and Repin, A.V. (2010, January 25\u201330). The Effect of Clay and Organic Matter Content on the Dielectric Permittivity of Soils and Grounds at the Frequency Range from 10 MHz to 1 GHz. Proceedings of the 2010 IEEE International Geoscience and Remote Sensing Symposium, Honolulu, HI, USA.","DOI":"10.1109\/IGARSS.2010.5652152"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"67","DOI":"10.2136\/sssaj2005.0067a","article-title":"Frequency dependence of the complex permittivity and its impact on dielectric sensor calibration in soils","volume":"69","author":"Kelleners","year":"2005","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"358","DOI":"10.2136\/vzj2007.0143","article-title":"Soil moisture measurement for ecological and hydrological watershed-scale observatories: A review","volume":"7","author":"Robinson","year":"2008","journal-title":"Vadose Zone J."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/2\/304\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:55:20Z","timestamp":1760194520000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/2\/304"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,2,16]]},"references-count":38,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2018,2]]}},"alternative-id":["rs10020304"],"URL":"https:\/\/doi.org\/10.3390\/rs10020304","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,2,16]]}}}