{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T14:46:10Z","timestamp":1775486770795,"version":"3.50.1"},"reference-count":53,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2021,12,11]],"date-time":"2021-12-11T00:00:00Z","timestamp":1639180800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005908","name":"Federal Ministry of Food and Agriculture","doi-asserted-by":"publisher","award":["2815710715 and 28DE114A18"],"award-info":[{"award-number":["2815710715 and 28DE114A18"]}],"id":[{"id":"10.13039\/501100005908","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Monitoring the phenological development of agricultural plants is of high importance for farmers to adapt their management strategies and estimate yields. The aim of this study is to analyze the sensitivity of remote sensing features to phenological development of winter wheat and winter barley and to test their transferability in two test sites in Northeast Germany and in two years. Local minima, local maxima and breakpoints of smoothed time series of synthetic aperture radar (SAR) data of the Sentinel-1 VH (vertical-horizontal) and VV (vertical-vertical) intensities and their ratio VH\/VV; of the polarimetric features entropy, anisotropy and alpha derived from polarimetric decomposition; as well as of the vegetation index NDVI (Normalized Difference Vegetation Index) calculated using optical data of Sentinel-2 are compared with entry dates of phenological stages. The beginning of stem elongation produces a breakpoint in the time series of most parameters for wheat and barley. Furthermore, the beginning of heading could be detected by all parameters, whereas particularly a local minimum of VH and VV backscatter is observed less then 5 days before the entry date. The medium milk stage can not be detected reliably, whereas the hard dough stage of barley takes place approximately 6\u20138 days around a local maximum of VH backscatter in 2018. Harvest is detected for barley using the fourth breakpoint of most parameters. The study shows that backscatter and polarimetric parameters as well as the NDVI are sensitive to specific phenological developments. The transferability of the approach is demonstrated, whereas differences between test sites and years are mainly caused by meteorological differences.<\/jats:p>","DOI":"10.3390\/rs13245036","type":"journal-article","created":{"date-parts":[[2021,12,13]],"date-time":"2021-12-13T01:29:33Z","timestamp":1639358973000},"page":"5036","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":39,"title":["Detecting Phenological Development of Winter Wheat and Winter Barley Using Time Series of Sentinel-1 and Sentinel-2"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4958-6391","authenticated-orcid":false,"given":"Katharina","family":"Harfenmeister","sequence":"first","affiliation":[{"name":"Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4879-8838","authenticated-orcid":false,"given":"Sibylle","family":"Itzerott","sequence":"additional","affiliation":[{"name":"Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2951-3614","authenticated-orcid":false,"given":"Cornelia","family":"Weltzien","sequence":"additional","affiliation":[{"name":"Technische Universit\u00e4t Berlin, Chair of Agromechatronics, Stra\u00dfe des 17. Juni 144, 10623 Berlin, Germany"},{"name":"Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Max-Eyth-Allee 100, 14469 Potsdam, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2939-8764","authenticated-orcid":false,"given":"Daniel","family":"Spengler","sequence":"additional","affiliation":[{"name":"Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1236","DOI":"10.1111\/gcb.12733","article-title":"A review of global potentially available cropland estimates and their consequences for model-based assessments","volume":"21","author":"Eitelberg","year":"2015","journal-title":"Glob. Chang. 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