{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,26]],"date-time":"2026-02-26T21:51:29Z","timestamp":1772142689441,"version":"3.50.1"},"reference-count":93,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2022,11,19]],"date-time":"2022-11-19T00:00:00Z","timestamp":1668816000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000781","name":"European Research Council (ERC) under the ERC-2017-STG SENTIFLEX project","doi-asserted-by":"publisher","award":["755617"],"award-info":[{"award-number":["755617"]}],"id":[{"id":"10.13039\/501100000781","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Ram\u00f3n y Cajal Contract (Spanish Ministry of Science, Innovation, and Universities)","award":["755617"],"award-info":[{"award-number":["755617"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Synthetic aperture radar (SAR) data provides an appealing opportunity for all-weather day or night Earth surface monitoring. The European constellation Sentinel-1 (S1) consisting of S1-A and S1-B satellites offers a suitable revisit time and spatial resolution for the observation of croplands from space. The C-band radar backscatter is sensitive to vegetation structure changes and phenology as well as soil moisture and roughness. It also varies depending on the local incidence angle (LIA) of the SAR acquisition\u2019s geometry. The LIA backscatter dependency could therefore be exploited to improve the retrieval of the crop biophysical variables. The availability of S1 radar time-series data at distinct observation angles holds the feasibility to retrieve leaf area index (LAI) evolution considering spatiotemporal coverage of intensively cultivated areas. Accordingly, this research presents a workflow merging multi-date S1 smoothed data acquired at distinct LIA with a Gaussian processes regression (GPR) and a cross-validation (CV) strategy to estimate cropland LAI of irrigated winter wheat. The GPR-S1-LAI model was tested against in situ data of the 2020 winter wheat campaign in the irrigated valley of Colorador river, South of Buenos Aires Province, Argentina. We achieved adequate validation results for LAI with RCV2 = 0.67 and RMSECV = 0.88 m2 m\u22122. The trained model was further applied to a series of S1 stacked images, generating temporal LAI maps that well reflect the crop growth cycle. The robustness of the retrieval workflow is supported by the associated uncertainties along with the obtained maps. We found that processing S1 smoothed imagery with distinct acquisition geometries permits accurate radar-based LAI modeling throughout large irrigated areas and in consequence can support agricultural management practices in cloud-prone agri-environments.<\/jats:p>","DOI":"10.3390\/rs14225867","type":"journal-article","created":{"date-parts":[[2022,11,21]],"date-time":"2022-11-21T04:33:32Z","timestamp":1669005212000},"page":"5867","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Quantifying Irrigated Winter Wheat LAI in Argentina Using Multiple Sentinel-1 Incidence Angles"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2268-2674","authenticated-orcid":false,"given":"Gabriel","family":"Caballero","sequence":"first","affiliation":[{"name":"Agri-Environmental Engineering, Technological University of Uruguay (UTEC), Av. Italia 6201, Montevideo 11500, Uruguay"},{"name":"Image Processing Laboratory (IPL), University of Valencia, C\/Catedr\u00e1tico Jos\u00e9 Beltr\u00e1n 2, Paterna, 46980 Valencia, Spain"}]},{"given":"Alejandro","family":"Pezzola","sequence":"additional","affiliation":[{"name":"Remote Sensing and SIG Laboratory, Hilario Ascasubi Agricultural Experimental Station, National Institute of Agricultural Technology (INTA), Hilario Ascasubi 8142, Argentina"}]},{"given":"Cristina","family":"Winschel","sequence":"additional","affiliation":[{"name":"Remote Sensing and SIG Laboratory, Hilario Ascasubi Agricultural Experimental Station, National Institute of Agricultural Technology (INTA), Hilario Ascasubi 8142, Argentina"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6718-3679","authenticated-orcid":false,"given":"Alejandra","family":"Casella","sequence":"additional","affiliation":[{"name":"Permanent Observatory of Agro-Ecosystems, Climate and Water Institute-National Agricultural Research Centre (ICyA-CNIA), National Institute of Agricultural Technology (INTA), Nicol\u00e1s Repetto s\/n, Hurlingham, Buenos Aires 1686, Argentina"}]},{"given":"Paolo","family":"Sanchez Angonova","sequence":"additional","affiliation":[{"name":"Remote Sensing and SIG Laboratory, Hilario Ascasubi Agricultural Experimental Station, National Institute of Agricultural Technology (INTA), Hilario Ascasubi 8142, Argentina"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6435-5965","authenticated-orcid":false,"given":"Luciano","family":"Orden","sequence":"additional","affiliation":[{"name":"Remote Sensing and SIG Laboratory, Hilario Ascasubi Agricultural Experimental Station, National Institute of Agricultural Technology (INTA), Hilario Ascasubi 8142, Argentina"},{"name":"Centro de Investigaci\u00f3n e Innovaci\u00f3n Agroalimentaria y Agroambiental (CIAGRO-UMH), GIAAMA Research Group, Universidad Miguel Hern\u00e1ndez, Carretera de Beniel Km, 03312 Orihuela, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0784-7717","authenticated-orcid":false,"given":"Katja","family":"Berger","sequence":"additional","affiliation":[{"name":"Image Processing Laboratory (IPL), University of Valencia, C\/Catedr\u00e1tico Jos\u00e9 Beltr\u00e1n 2, Paterna, 46980 Valencia, Spain"},{"name":"Mantle Labs GmbH, Gr\u00fcnentorgasse 19\/4, 1090 Vienna, Austria"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6313-2081","authenticated-orcid":false,"given":"Jochem","family":"Verrelst","sequence":"additional","affiliation":[{"name":"Image Processing Laboratory (IPL), University of Valencia, C\/Catedr\u00e1tico Jos\u00e9 Beltr\u00e1n 2, Paterna, 46980 Valencia, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2819-6979","authenticated-orcid":false,"given":"Jes\u00fas","family":"Delegido","sequence":"additional","affiliation":[{"name":"Image Processing Laboratory (IPL), University of Valencia, C\/Catedr\u00e1tico Jos\u00e9 Beltr\u00e1n 2, Paterna, 46980 Valencia, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,19]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"Estimating the Leaf Area Index, height and biomass of maize using HJ-1 and RADARSAT-2","volume":"24","author":"Gao","year":"2013","journal-title":"Int. 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