{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,26]],"date-time":"2025-10-26T14:56:50Z","timestamp":1761490610431,"version":"build-2065373602"},"reference-count":52,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2018,7,7]],"date-time":"2018-07-07T00:00:00Z","timestamp":1530921600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100011937","name":"Nieders\u00e4chsische Ministerium f\u00fcr Wissenschaft und Kultur","doi-asserted-by":"publisher","award":["VWZN2869"],"award-info":[{"award-number":["VWZN2869"]}],"id":[{"id":"10.13039\/100011937","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Nieders\u00e4chsisches Ministerium f\u00fcr Umwelt, Energie, Bauen und Klimaschutz","award":["VWZN2869"],"award-info":[{"award-number":["VWZN2869"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Spatial distribution and dynamics of intertidal habitats are integral elements of the Wadden Sea ecosystem, essential for the preservation of ecosystem functions and interlocked with geomorphological processes. Protection and monitoring of the Wadden Sea is mandatory and remote sensing is required to survey the extensive, often inaccessible tidal area. Mainly airborne techniques are carried out for decades. High-resolution satellite-borne sensors now enable new possibilities with satellite synthetic aperture radar (SAR) offering high availability of acquisitions during low water time due to independence from daylight and cloud cover. More than 100 TerraSAR-X images from 2009 to 2016 were used to examine the reproduction of intertidal habitats and macrostructures from the flats south of the island of Norderney and comparative areas in the Lower Saxony Wadden Sea. As a non-specific, generic approach to distinguish various and variable surface types continuously influenced by tidal dynamics, visual analysis was chosen which was supported by extensive in situ data. This technically unsophisticated access enabled us to identify mussel beds, fields of shell-detritus, gully structures, mud fields, and bedforms, the latter detected in the upper flats of every East Frisian island. Based on the high frequency of TerraSAR-X recordings for the Norderney area, a bedform shift was observed in a time-series from 2009 to 2015. For the same period, the development of a mud field with an adjoining depression was traced. Beside seasonal variations of the mud field, the formation of a mussel bed settling in the depression was imaged over the years. This study exemplifies the relevance of TerraSAR-X imagery for Wadden Sea remote sensing. Further development of classification methods for current SAR data together with open access availability should contribute to large-scale surveys of intertidal surface structures of geomorphic or biogenic origin and improve monitoring and long-term ecological research in the Wadden Sea and related tidal areas.<\/jats:p>","DOI":"10.3390\/rs10071085","type":"journal-article","created":{"date-parts":[[2018,7,9]],"date-time":"2018-07-09T11:18:53Z","timestamp":1531135133000},"page":"1085","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Remote Sensing Intertidal Flats with TerraSAR-X. A SAR Perspective of the Structural Elements of a Tidal Basin for Monitoring the Wadden Sea"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1541-8269","authenticated-orcid":false,"given":"Winny","family":"Adolph","sequence":"first","affiliation":[{"name":"Wadden Sea National Park Authority of Lower Saxony (NLPV), Virchowstr.1, 26382 Wilhelmshaven, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5226-548X","authenticated-orcid":false,"given":"Hubert","family":"Farke","sequence":"additional","affiliation":[{"name":"Wadden Sea National Park Authority of Lower Saxony (NLPV), Virchowstr.1, 26382 Wilhelmshaven, Germany"}]},{"given":"Susanne","family":"Lehner","sequence":"additional","affiliation":[{"name":"Susanne Lehner, German Aerospace Center (DLR), Remote Sensing Technology Institute (IMF), Oberpfaffenhofen, 82234 We\u00dfling, Germany"}]},{"given":"Manfred","family":"Ehlers","sequence":"additional","affiliation":[{"name":"Institute for Geoinformatics and Remote Sensing (IGF), University of Osnabr\u00fcck, Wachsbleiche 27, 49090 Osnabr\u00fcck, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2018,7,7]]},"reference":[{"key":"ref_1","unstructured":"Millat, G. (1996). Entwicklung Eines Methodisch-Inhaltlichen Konzeptes zum Einsatz von Fernerkundungsdaten f\u00fcr ein Umweltmonitoring im Nieders\u00e4chsischen Wattenmeer, Schriftenreihe der Nationalparkverwaltung Nieders\u00e4chsisches Wattenmeer."},{"key":"ref_2","unstructured":"Herlyn, M., and Millat, G. (2004). Wissenschaftliche Begleituntersuchungen zur Aufbauphase des Miesmuschelmanagements im Nationalpark \u201cNieders\u00e4chsisches Wattenmeer\u201d, (unpublished data)."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1016\/j.seares.2004.07.002","article-title":"Quantitative assessment of intertidal blue mussel (Mytilus edulis L.) stocks: Combined methods of remote sensing, field investigation and sampling","volume":"53","author":"Herlyn","year":"2005","journal-title":"J. Sea Res."},{"key":"ref_4","unstructured":"Ringot, J.L. (1992\/1993). Erstellen eines Interpretationsschl\u00fcssels und Kartierung der Biotoptypen terrestrischer Bereiche des Nationalparks Nieders\u00e4chsisches Wattenmeer auf der Basis des CIR-Bildfluges vom 21.08.1991, (unpublished data)."},{"key":"ref_5","unstructured":"Marencic, H., and Vlas, J. (2009). Salt Marshes. Thematic Report No. 8. Quality Status Report 2009\u2014Wadden Sea Ecosystem 25, Common Wadden Sea Secretariat, Trilateral Monitoring and Assessment Group."},{"key":"ref_6","first-page":"75","article-title":"Applied vegetation mapping of large-scale areas based on high resolution aerial photographs\u2014A combined method of remote sensing, GIS and near comprehensive field verification","volume":"26","author":"Petersen","year":"2010","journal-title":"Wadden Sea Ecosyst."},{"key":"ref_7","first-page":"1","article-title":"Erfassung der Seegrasbest\u00e4nde im nieders\u00e4chsischen Wattenmeer \u00fcber visuelle Luftbildinterpretation\u20142008","volume":"4","author":"Kolbe","year":"2011","journal-title":"K\u00fcstengew\u00e4sser und \u00c4stuare"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1109\/MGRS.2013.2248301","article-title":"A tutorial on synthetic aperture radar","volume":"1","author":"Moreira","year":"2013","journal-title":"IEEE Geosci. Remote Sens. Mag."},{"key":"ref_9","unstructured":"Stelzer, K., and Brockmann, C. (2018, April 27). Operationalisierung von Fernerkundungsmethoden f\u00fcrs Wattenmeermonitoring (OFEW). Available online: http:\/\/docplayer.org\/7506004-Operationalisierung-von-fernerkundungsmethoden-fuer-das-wattenmeermonitoring-zusammenfassung.html."},{"key":"ref_10","unstructured":"Stelzer, K., Gei\u00dfler, J., Gade, M., Eskildsen, K., Kohlus, J., Farke, H., and Reimers, H.-C. (2010). DeMarine Umwelt: Operationalisierung Mariner GMES-Dienste in Deutschland. Integration optischer und SAR Erdbeobachtungsdaten f\u00fcr das Wattenmeermonitoring, Bundesamt f\u00fcr Seeschifffahrt und Hydrographie. Jahresbericht 2009\u20132010."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"M\u00fcller, G., Stelzer, K., Smollich, S., Gade, M., Adolph, W., Melchionna, S., Kemme, L., Gei\u00dfler, J., Millat, G., and Reimers, H.-C. (2016). Remotely sensing the German Wadden Sea\u2014A new approach to address national and international environmental legislation. Environ. Monit. Assess., 188.","DOI":"10.1007\/s10661-016-5591-x"},{"key":"ref_12","unstructured":"Winter, C., Backer, V., Adolph, W., Bartholom\u00e4, A., Becker, M., Behr, D., Callies, C., Capperucci, R., Ehlers, M., and Farke, H. (2016). WIMO\u2014Wissenschaftliche Monitoringkonzepte f\u00fcr die Deutsche Bucht, Available online: http:\/\/dx.doi.org\/10.2314\/gbv:860303926."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1007\/s00367-017-0496-4","article-title":"Monitoring concepts for an evaluation of marine environmental states in the German Bight","volume":"37","author":"Winter","year":"2017","journal-title":"Geo-Mar. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1603","DOI":"10.1016\/j.rse.2007.08.015","article-title":"Classification of sediments on exposed tidal flats in the German Bight using multi-frequency radar data","volume":"112","author":"Gade","year":"2008","journal-title":"Remote Sens. Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"188","DOI":"10.1016\/j.rse.2015.09.018","article-title":"A multi-sensor approach for detecting the different land covers of tidal flats in the German Wadden Sea\u2014A case study at Norderney","volume":"170","author":"Jung","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Gade, M. (2016, January 10\u201315). A polarimetric radar view at exposed intertidal flats. Proceedings of the 2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China.","DOI":"10.1109\/IGARSS.2016.7730050"},{"key":"ref_17","unstructured":"Jung, R. (2015). A Multi-Sensor Approach for Land Cover Classification and Monitoring of Tidal Flats in the German Wadden Sea. [Ph.D. Dissertation, University of Osnabrueck]."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1191","DOI":"10.5194\/isprs-archives-XLI-B8-1191-2016","article-title":"Random Forest Classification of Sediments on Exposed Intertidal Flats Using ALOS-2 Quad-Polarimetric SAR Data","volume":"8","author":"Wang","year":"2016","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1007\/s00367-016-0478-y","article-title":"Monitoring spatiotemporal trends in intertidal bedforms of the German Wadden Sea in 2009\u20132015 with TerraSAR-X, including links with sediments and benthic macrofauna","volume":"37","author":"Adolph","year":"2017","journal-title":"Geo-Mar. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1007\/s00367-016-0485-z","article-title":"Integration of TerraSAR-X, RapidEye and airborne lidar for remote sensing of intertidal bedforms on the upper flats of Norderney (German Wadden Sea)","volume":"37","author":"Adolph","year":"2017","journal-title":"Geo-Mar. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1016\/j.rse.2016.01.009","article-title":"Study of the polarimetric characteristics of mud flats in an intertidal zone using C- and X-band spaceborne SAR data","volume":"176","author":"Geng","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"223","DOI":"10.5194\/isprs-archives-XLII-3-W2-223-2017","article-title":"A new SAR classification scheme for sediments on intertidal flats based on multi-frequency polarimetric SAR imagery","volume":"XLII-3\/W2","author":"Wang","year":"2017","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/j.rse.2017.12.004","article-title":"On the imaging of exposed intertidal flats by single- and dual-co-polarization Synthetic Aperture Radar","volume":"205","author":"Gade","year":"2018","journal-title":"Remote Sens. Environ."},{"key":"ref_24","unstructured":"Albertz, J. (2009). Einf\u00fchrung in die Fernerkundung. Grundlagen der Interpretation von Luft- und Satellitenbildern, Wissenschaftliche Buchgesellschaft. [4th ed.]."},{"key":"ref_25","unstructured":"de Batist, M., and Jacobs, P. (1996). Nearshore sediment transport processes due to moderate hydrodynamic conditions. Geology of Siliciclastic Shelf Seas, Geological Society."},{"key":"ref_26","unstructured":"Leatherman, S.P. (1979). Barrier islands morphology as a function of tidal and wave regime. Barrier Islands, Academic Press."},{"key":"ref_27","unstructured":"Fritz, T., and Eineder, M. (2018, April 27). TerraSAR-X Ground Segment Basic Product Specification Document. Available online: http:\/\/sss.terrasar-x.dlr.de\/docs\/TX-GS-DD-3302.pdf."},{"key":"ref_28","unstructured":"Airbus Defence & Space (2018, April 27). Radiometric Calibration of TerraSAR-X Data. Beta Naught and Sigma Naught Coefficient Calculation. Available online: https:\/\/dep1doc.gfz-potsdam.de\/attachments\/download\/365\/r465_9_tsx-x-itd-tn-0049-radiometric_calculations_i3.00.pdf."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"610","DOI":"10.1109\/TSMC.1973.4309314","article-title":"Textural Features for Image Classification","volume":"3","author":"Haralick","year":"1973","journal-title":"IEEE Trans. Syst. Man. Cybern."},{"key":"ref_30","unstructured":"Farke, H. (2011). DeMarine-Umwelt: TP 4\u2014Integration Optischer und SAR Beobachtungsdaten f\u00fcr das Wattenmeermonitoring, Available online: http:\/\/dx.doi.org\/10.2314\/gbv:722405367."},{"key":"ref_31","unstructured":"NLPV (2018, April 26). Monitoring Data: Aerial Mapping for Annual Mussel Monitoring. Available online: http:\/\/www.nationalpark-wattenmeer.de\/nds\/service\/publikationen\/1130_muschelwildb\u00e4nke-von-borkum-bis-cuxhaven-gis-daten."},{"key":"ref_32","unstructured":"(2018, April 28). Deutscher Wetterdienst (DWD). Available online: www.dwd.de\/DE\/presse\/pressemitteilungen\/DE\/2014\/20140730_Deutschlandwetter_Juli_2014.html."},{"key":"ref_33","unstructured":"(2018, April 28). UnwetterZentrale. Available online: http:\/\/www.unwetterzentrale.de\/uwz\/955.html."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1701","DOI":"10.1109\/TGRS.2010.2084094","article-title":"Radar Backscattering of Intertidal Mudflats Observed by Radarsat-1 SAR Images and Ground-Based Scatterometer Experiments","volume":"49","author":"Lee","year":"2011","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.ecss.2011.11.007","article-title":"Detection of oyster habitat in tidal flats using multi-frequency polarimetric SAR data","volume":"97","author":"Choe","year":"2012","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2573","DOI":"10.1587\/transcom.E96.B.2573","article-title":"Sandbank and Oyster Farm Monitoring with Multi-Temporal Polarimetric SAR Data Using Four-Component Scattering Power Decomposition","volume":"96","author":"Cheng","year":"2013","journal-title":"IEICE Trans. Commun."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"941","DOI":"10.5194\/isprsarchives-XL-7-W3-941-2015","article-title":"Analyses of multi-year synthetic aperture radar imagery of dry-fallen intertidal flats","volume":"XL-7\/W3","author":"Gade","year":"2015","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ecss.2016.01.025","article-title":"Joint use of multiple Synthetic Aperture Radar imagery for the detection of bivalve beds and morphological changes on intertidal flats","volume":"171","author":"Gade","year":"2016","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1022","DOI":"10.1109\/TGRS.2008.2008908","article-title":"Estimation of Surface Roughness Parameter in Intertidal Mudflat Using Airborne Polarimetric SAR Data","volume":"47","author":"Park","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Ryu, J.-H., Eom, J.A., and Choi, J.-K. (2010, January 25\u201330). Application of airborne remote sensing to the surface sediment classification in a tidal flat. Proceedings of the IGARSS 2010: 2010 IEEE International Geoscience and Remote Sensing Symposium, Honolulu, HI, USA.","DOI":"10.1109\/IGARSS.2010.5653413"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1007\/s12303-012-0015-6","article-title":"Tidal channel distribution in relation to surface sedimentary facies based on remotely sensed data","volume":"16","author":"Eom","year":"2012","journal-title":"Geosci. J."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/j.margeo.2010.10.022","article-title":"Spatial relationships between surface sedimentary facies distribution and topography using remotely sensed data: Example from the Ganghwa tidal flat, Korea","volume":"280","author":"Choi","year":"2011","journal-title":"Mar. Geol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"487","DOI":"10.1016\/j.ecss.2010.01.015","article-title":"Remote sensing of intertidal morphological change in Morecambe Bay, U.K., between 1991 and 2007","volume":"87","author":"Mason","year":"2010","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1029","DOI":"10.5194\/isprsarchives-XL-7-W3-1029-2015","article-title":"Waterline detection and monitoring in the German Wadden Sea using high resolution satellite-based Radar measurements","volume":"XL-7\/W3","author":"Wiehle","year":"2015","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_45","unstructured":"J\u00fcrgens, C. (2008). Image Fusion of High Resolution TerraSAR-X and Multispectral Electro-Optical Data for Improved Spatial Resolution. Remote Sensing\u2014New Challenges of High Resolution, EARsel Joint Workshop."},{"key":"ref_46","unstructured":"Klonus, S., and Ehlers, M. (2009, January 15\u201318). Additional Benefit of Image Fusion Method from Combined High Resolution TerraSAR-X and Multispectral SPOT Data for Classification. Proceedings of the 29th Annual EARSeL Symposium, Chania, Kreta."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Rosso, P.H., Michel, U., Civco, D.L., Ehlers, M., and Klonus, S. (2009, January 31). Interpretability of TerraSAR-X fused data. Proceedings of the SPIE Europe Remote Sensing, Berlin, Germany.","DOI":"10.1117\/12.830528"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Metz, A., Schmitt, A., Esch, T., Reinartz, P., Klonus, S., and Ehlers, M. (2012, January 22\u201327). Synergetic use of TerraSAR-X and Radarsat-2 time series data for identification and characterization of grassland types\u2014A case study in Southern Bavaria, Germany. Proceedings of the 2012 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany.","DOI":"10.1109\/IGARSS.2012.6350649"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.rse.2007.03.019","article-title":"Regression-based synergy of optical, shortwave infrared and microwave remote sensing for monitoring the grain-size of intertidal sediments","volume":"111","author":"Herman","year":"2007","journal-title":"Remote Sens. Environ."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1016\/j.ecss.2014.01.007","article-title":"Multi-frequency SAR data help improving the monitoring of intertidal flats on the German North Sea coast","volume":"140","author":"Gade","year":"2014","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2448","DOI":"10.1109\/LGRS.2015.2483680","article-title":"Multiview Deep Learning for Land-Use Classification","volume":"12","author":"Luus","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"2811","DOI":"10.1109\/TGRS.2017.2783902","article-title":"When Deep Learning Meets Metric Learning: Remote Sensing Image Scene Classification via Learning Discriminative CNNs","volume":"99","author":"Cheng","year":"2018","journal-title":"IEEE Trans. Geosci. Remote Sens."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/7\/1085\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:11:39Z","timestamp":1760195499000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/7\/1085"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,7,7]]},"references-count":52,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2018,7]]}},"alternative-id":["rs10071085"],"URL":"https:\/\/doi.org\/10.3390\/rs10071085","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2018,7,7]]}}}