{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T22:10:05Z","timestamp":1777587005717,"version":"3.51.4"},"reference-count":46,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2018,8,28]],"date-time":"2018-08-28T00:00:00Z","timestamp":1535414400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key Research and Development Program of China; National Natural Science Foundation of China; National Social Science Foundation of China; New-Shoot Talented Man Plan Project of Zhejiang Provence","award":["017YFA0604901,2016YFC1402000;41776183,41676014;15ZDB170;2018R411065"],"award-info":[{"award-number":["017YFA0604901,2016YFC1402000;41776183,41676014;15ZDB170;2018R411065"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>In this study, an empirical algorithm is proposed to retrieve significant wave height (SWH) from dual-polarization Sentinel-1 (S-1) synthetic aperture radar (SAR) imagery collected under cyclonic conditions. The retrieval scheme is based on the well-known CWAVE empirical function that is here updated to deal with multi-polarization S-1 SAR measurements collected using the interferometric wide (IW) and the Extra Wide-Swath (EW) imaging modes, under cyclonic conditions. First, a training dataset that consists of six S-1 SAR images collected under cyclonic conditions is exploited to both tune the retrieval function and to check the soundness of the retrievals against the co-located WAVEWATCH-III (WW3) numerical simulations. The comparison of simulation from the WW3 model and measurements from altimeter Jason-2 shows a 0.29m root mean square error (RMSE) of significant wave height (SWH). Then, a testing data-set that consists of two S-1 SAR images is exploited to provide a preliminary validation. The results, verified against both WW3 and European Centre for Medium-Range Weather Forecasts (ECMWF) data, show the soundness of the herein approach.<\/jats:p>","DOI":"10.3390\/rs10091367","type":"journal-article","created":{"date-parts":[[2018,8,28]],"date-time":"2018-08-28T12:19:06Z","timestamp":1535458746000},"page":"1367","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":25,"title":["An Empirical Algorithm to Retrieve Significant Wave Height from Sentinel-1 Synthetic Aperture Radar Imagery Collected under Cyclonic Conditions"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3693-6217","authenticated-orcid":false,"given":"Weizeng","family":"Shao","sequence":"first","affiliation":[{"name":"Marine Science and Technology College, Zhejiang Ocean University, Zhoushan 316000, China"},{"name":"State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuyi","family":"Hu","sequence":"additional","affiliation":[{"name":"Marine Science and Technology College, Zhejiang Ocean University, Zhoushan 316000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7514-3212","authenticated-orcid":false,"given":"Jingsong","family":"Yang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4567-0377","authenticated-orcid":false,"given":"Ferdinando","family":"Nunziata","sequence":"additional","affiliation":[{"name":"Dipartimento di Ingegneria, Universit\u00e0 degli Studi di Napoli Parthenope, 80133 Napoli, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5692-2547","authenticated-orcid":false,"given":"Jian","family":"Sun","sequence":"additional","affiliation":[{"name":"Physical Oceanography Laboratory, Ocean University of China, Qingdao 266100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huan","family":"Li","sequence":"additional","affiliation":[{"name":"National Marine Data and Information Service, Tianjin 300171, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Juncheng","family":"Zuo","sequence":"additional","affiliation":[{"name":"Marine Science and Technology College, Zhejiang Ocean University, Zhoushan 316000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,8,28]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"The first Sentinel-1 SAR image of a typhoon","volume":"34","author":"Li","year":"2015","journal-title":"Acta Oceanol. Sin."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1639","DOI":"10.1109\/TGRS.2009.2037143","article-title":"Tropical cyclone intensity estimated from Wide-Swath SAR images","volume":"48","author":"Reppucci","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1175\/BAMS-D-11-00211.1","article-title":"Tropical cyclone morphology from spaceborne synthetic aperture radar","volume":"94","author":"Li","year":"2013","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2131","DOI":"10.1109\/TGRS.2002.802474","article-title":"Observation of hurricane-generated ocean swell refraction at the gulf stream north wall with the RADARSAT-1 synthetic aperture radar","volume":"40","author":"Li","year":"2002","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"77","DOI":"10.5194\/nhess-9-77-2009","article-title":"Rainfall observation from X-band, space-borne, synthetic aperture radar","volume":"9","author":"Weinman","year":"2009","journal-title":"Nat. Hazards Earth Syst. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1109\/JOE.2017.2700558","article-title":"Megi typhoon monitoring by X-band synthetic aperture radar measurements","volume":"1","author":"Corcione","year":"2018","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"10713","DOI":"10.1029\/91JC00302","article-title":"On the nonlinear mapping of an ocean wave spectrum into a synthetic aperture radar image spectrum","volume":"96","author":"Hasselmann","year":"1991","journal-title":"J. Geophys. Res."},{"key":"ref_8","first-page":"6615","article-title":"An improved algorithm for the retrieval of ocean wave spectra from synthetic aperture radar image spectra","volume":"101","author":"Hasselmann","year":"1996","journal-title":"J. Geophys. Res."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"526","DOI":"10.1109\/JOE.2005.857503","article-title":"Extraction of coastal ocean wave fields from SAR images","volume":"30","author":"Collard","year":"2005","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3497","DOI":"10.1029\/1999JC900282","article-title":"A semi-parametric algorithm to retrieve ocean wave spectra from synthetic aperture radar","volume":"105","author":"Mastenbroek","year":"2000","journal-title":"J. Geophys. Res."},{"key":"ref_11","first-page":"297","article-title":"A parametric scheme for the retrieval of two-dimensional ocean wave spectra from synthetic aperture radar look cross spectra","volume":"110","author":"Lehner","year":"2005","journal-title":"J. Geophys. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1007\/BF02842769","article-title":"Parameterized first-guess spectrum method for retrieving directional spectrum of swell-dominated waves and huge waves from SAR images","volume":"24","author":"Sun","year":"2006","journal-title":"Chin. J. Oceanol. Limnol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"12815","DOI":"10.3390\/rs71012815","article-title":"Ocean wave parameters retrieval from TerraSAR-X images validated against buoy measurements and model results","volume":"7","author":"Shao","year":"2015","journal-title":"Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1007\/s13131-017-1089-9","article-title":"Development and validation of an ocean wave retrieval algorithm for VV-polarization Sentinel-1 SAR data","volume":"36","author":"Lin","year":"2017","journal-title":"Acta Oceanol. Sin."},{"key":"ref_15","first-page":"1","article-title":"An empirical approach for the retrieval of integral ocean wave parameters from synthetic aperture radar data","volume":"112","author":"Konig","year":"2007","journal-title":"J. Geophys. Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1109\/TGRS.2010.2052364","article-title":"Ocean wave integral parameter measurements using Envisat ASAR wave mode data","volume":"49","author":"Li","year":"2011","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"7616","DOI":"10.1002\/2015JC011275","article-title":"Estimating wave orbital velocities through the azimuth cut-off from space borne satellites","volume":"120","author":"Stopa","year":"2016","journal-title":"J. Geophys. Res."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Shao, W.Z., Zhang, Z., Li, X.F., and Li, H. (2016). Ocean wave parameters retrieval from Sentinel-1 SAR imagery. Remote Sens., 8.","DOI":"10.3390\/rs8090707"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s13131-018-1217-1","article-title":"Validation of significant wave height retrieval from co-polarization Chinese Gaofen-3 SAR imagery","volume":"37","author":"Sheng","year":"2018","journal-title":"Acta Oceanol. Sin."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Wang, H., Wang, J., Yang, J.S., Ren, L., Zhu, J.H., Yuan, X.Z., and Xie, C.H. (2018). Empirical algorithm for significant wave height retrieval from wave mode data provided by the Chinese satellite Gaofen-3. Remote Sens., 10.","DOI":"10.3390\/rs10030363"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"10529","DOI":"10.1029\/JC086iC07p06481","article-title":"On the detectability of ocean surface waves by real and synthetic radar","volume":"86","author":"Alpers","year":"1981","journal-title":"J. Geophys. Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"873","DOI":"10.1109\/TGRS.1986.289702","article-title":"On the relative importance of motion-related contributions to SAR imaging mechanism of ocean surface waves","volume":"24","author":"Alpers","year":"1986","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"7767","DOI":"10.1029\/97JC01911","article-title":"Observation of tropical cyclones by high-resolution scatterometry","volume":"103","author":"Quilfen","year":"1998","journal-title":"J. Geophys. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"C03006","DOI":"10.1029\/2006JC003743","article-title":"An improved C-band scatterometer ocean geophysical model function: CMOD5","volume":"112","author":"Hersbach","year":"2007","journal-title":"J. Geophys. Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"721","DOI":"10.1175\/2009JTECHO698.1","article-title":"Comparison of C-band scatterometer CMOD5.N equivalent neutral winds with ECMWF","volume":"27","author":"Hersbach","year":"2010","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"7195","DOI":"10.1002\/2015JC011149","article-title":"Global C-band Envisat, RADARSAT-2 and Sentinel-1 SAR measurements in copolarization and cross-polarization","volume":"120","author":"Mouche","year":"2006","journal-title":"J. Geophys. Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2417","DOI":"10.1109\/JSTARS.2018.2836661","article-title":"A C-band geophysical model function for determining coastal wind speed using synthetic aperture radar","volume":"11","author":"Lu","year":"2018","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"456","DOI":"10.1109\/LGRS.2010.2085417","article-title":"C-band cross-polarization wind speed retrieval","volume":"3","author":"Vachon","year":"2011","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4252","DOI":"10.1109\/TGRS.2012.2194157","article-title":"Ocean vector winds retrieval from C-band fully polarimetric SAR measurements","volume":"50","author":"Zhang","year":"2012","journal-title":"IEEE Geosci. Remote Sens."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"5820","DOI":"10.1109\/TGRS.2013.2293143","article-title":"Wind speed retrieval from VH dual-polarization RADARSAT-2 SAR images","volume":"52","author":"Shen","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"893","DOI":"10.1002\/2014JC010439","article-title":"Cross polarization geophysical model function for C-band radar backscattering from the ocean surface and wind speed retrieval","volume":"120","author":"Hwang","year":"2015","journal-title":"J. Geophys. Res."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1320","DOI":"10.1109\/TGRS.2014.2337663","article-title":"A new approach to ocean wave parameter estimates from C-band ScanSAR images","volume":"53","author":"Romeiser","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Ji, Q., Shao, W., Sheng, Y.X., Yuan, X.Z., Sun, J., Zhou, W., and Zuo, J.C. (2018). A promising method of cyclone wave retrieval from Gaofen-3 synthetic aperture radar image in VV-polarization. Sensors, 18.","DOI":"10.3390\/s18072064"},{"key":"ref_34","first-page":"59","article-title":"A semi-empirical algorithm for SAR wave height retrieval and its validation using Envisat ASAR wave mode data","volume":"31","author":"Wang","year":"2012","journal-title":"Acta Oceanol. Sin."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1007\/s13131-015-0769-6","article-title":"Significant wave height estimation using azimuth cutoff of C-band RADARSAT-2 single-polarization SAR images","volume":"34","author":"Ren","year":"2015","journal-title":"Acta Oceanol. Sin."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"5086","DOI":"10.1080\/01431161.2016.1226525","article-title":"Dependency of the Sentinel-1 azimuth wavelength cut-off on significant wave height and wind speed","volume":"37","author":"Grieco","year":"2016","journal-title":"Int. J. Remote Sens."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Shao, W.Z., Wang, J., Li, X.F., and Sun, J. (2017). An empirical algorithm for wave retrieval from co-polarization X-band SAR imagery. Remote Sens., 9.","DOI":"10.3390\/rs9070711"},{"key":"ref_38","unstructured":"The WAVEWATCH III Development Group (WW3DG) (2016). User Manual and System Documentation of WAVEWATCH III, Version 5.16; Tech. Note 329."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"7957","DOI":"10.1175\/JCLI-D-16-0219.1","article-title":"Wind and wave climate in the Arctic ocean as observed by altimeters","volume":"29","author":"Liu","year":"2016","journal-title":"J. Clim."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"763","DOI":"10.1175\/1520-0434(1997)012<0763:VOTEWF>2.0.CO;2","article-title":"Verification of the ECMWF wave forecasting system against buoy and altimeter data","volume":"12","author":"Janssen","year":"1997","journal-title":"Weather Forecast."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/j.ocemod.2013.12.006","article-title":"Intercomparison of wind and wave data from the ECMWF reanalysis interim and the NECP climate forecast system reanalysis","volume":"75","author":"Stopa","year":"2014","journal-title":"Ocean Model."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1175\/JCLI-D-14-00470.1","article-title":"Marine wind and wave height trends at different ERA-Interim forecast ranges","volume":"28","author":"Aarnes","year":"2015","journal-title":"J. Clim."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1007\/s13131-015-0737-1","article-title":"Evaluation of the simulation capability of the Wavewatch III model for Pacific Ocean wave","volume":"34","author":"Bi","year":"2015","journal-title":"Acta Oceanol. Sin."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"8419580","DOI":"10.1155\/2016\/8419580","article-title":"Analysis of the global swell and wind-sea energy distribution using WAVEWATCH III","volume":"2016","author":"Zheng","year":"2016","journal-title":"Adv. Meteorol."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Shao, W.Z., Sheng, Y.X., Li, H., Shi, J., Ji, Q.Y., Tan, W., and Zuo, J.C. (2018). Analysis of wave distribution simulated by WAVEWATCH-III model in typhoons passing Beibu Gulf, China. Atmosphere, 9.","DOI":"10.3390\/atmos9070265"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"6714","DOI":"10.1002\/2017JC012908","article-title":"Bridging the gap between cyclone wind and wave by C-band SAR measurements","volume":"122","author":"Shao","year":"2017","journal-title":"J. Geophys. Res."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/9\/1367\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:21:42Z","timestamp":1760196102000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/9\/1367"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,8,28]]},"references-count":46,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2018,9]]}},"alternative-id":["rs10091367"],"URL":"https:\/\/doi.org\/10.3390\/rs10091367","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,8,28]]}}}