{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,20]],"date-time":"2026-01-20T14:46:24Z","timestamp":1768920384372,"version":"3.49.0"},"reference-count":20,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2018,7,10]],"date-time":"2018-07-10T00:00:00Z","timestamp":1531180800000},"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>This paper reports on an investigation on the influence of waves on the sea surface height error, \u03c3h, as measured by Delay Doppler satellite altimetry (DDA). CryoSat-2 altimeter sea surface height (SSH) data in the North Sea, processed in both DDA and pseudo low resolution mode (PLRM), are correlated with European Centre for Medium-Range Weather Forecasts (ECMWF) co-located sea state data. We find a small, but consistent correlation between the 1 Hz standard deviation, \u03c3h, of the 20 Hz altimeter SSH and the ECMWF total significant wave height, SWHt. The same analysis carried out between \u03c3h and the swell component of the wave spectrum shows a smaller correlation. In contrast, the correlation between the PLRM \u03c3h and any component of the SWH spectrum has not been found to be significant. To provide an explanation of these results, the aliasing effect caused by the interaction between the sea wavelength and the altimeter resolution has been considered; a simple model has, therefore, been produced to simulate the dependence of the aliasing-derived, \u03c3A, on the sea wavelength. The alias\/wavelength curve obtained helps to explain why\u2014at least for the relatively low wavelength sea data considered\u2014the wave direction and its wavelength have little or no influence on \u03c3h.<\/jats:p>","DOI":"10.3390\/rs10071100","type":"journal-article","created":{"date-parts":[[2018,7,11]],"date-time":"2018-07-11T03:24:19Z","timestamp":1531279459000},"page":"1100","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Influence of Sea State on Sea Surface Height Oscillation from Doppler Altimeter Measurements in the North Sea"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6146-4023","authenticated-orcid":false,"given":"Ferdinando","family":"Reale","sequence":"first","affiliation":[{"name":"Department of Civil Engineering, University of Salerno, 84084 Fisciano, Italy"}]},{"given":"Fabio","family":"Dentale","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, University of Salerno, 84084 Fisciano, Italy"},{"name":"Inter-University National Consortium for Marine Sciences (CoNISMa), 00196 Roma, Italy"}]},{"given":"Eugenio Pugliese","family":"Carratelli","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, University of Salerno, 84084 Fisciano, Italy"},{"name":"Inter-University National Consortium for Marine Sciences (CoNISMa), 00196 Roma, Italy"}]},{"given":"Luciana","family":"Fenoglio-Marc","sequence":"additional","affiliation":[{"name":"Institute of Geodesy and Geoinformation, University of Bonn, 53115 Bonn, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2018,7,10]]},"reference":[{"key":"ref_1","unstructured":"Stein, T. (1998, January 6\u201310). Delay\/Doppler radar altimeter: Better measurement precision. Proceedings of the IGARSS \u201998: Sensing and Managing the Environment: 1998 IEEE International Geoscience and Remote Sensing Symposium, Seattle, WA, USA."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1578","DOI":"10.1109\/36.718861","article-title":"The Delay\/Doppler Radar Altimeter","volume":"36","author":"Raney","year":"1998","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1109\/LAWP.2010.2046471","article-title":"The Rough Surface Impulse Response of a Pulse-Limited Altimeter with an Elliptical Antenna Pattern","volume":"9","author":"Wingham","year":"2010","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"660","DOI":"10.2112\/SI65-112.1","article-title":"Sea wave numerical simulations with COSMO-SkyMed\u00a9 SAR data","volume":"1","author":"Benassai","year":"2013","journal-title":"J. Coast. Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3681","DOI":"10.3390\/rs6053681","article-title":"Numerical Simulation of Whitecaps and Foam Effects on Satellite Altimeter Response","volume":"6","author":"Reale","year":"2014","journal-title":"Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"13606","DOI":"10.3390\/rs71013606","article-title":"Estimating the Augmented Reflectance Ratio of the Ocean Surface When Whitecaps Appear","volume":"7","author":"Xu","year":"2015","journal-title":"Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1337","DOI":"10.1175\/JTECH-D-13-00081.1","article-title":"Investigating Short-Wavelength Correlated Errors on Low-Resolution Mode Altimetry","volume":"31","author":"Dibarboure","year":"2014","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"14509","DOI":"10.3390\/rs71114509","article-title":"Impact of Surface Waves on SWOT\u2019s Projected Ocean Accuracy","volume":"7","author":"Peral","year":"2015","journal-title":"Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Hwang, P.A., and Plant, W.J. (2010). An analysis of the effects of swell and surface roughness spectra on microwave backscatter from the ocean. J. Geophys. Res., 115.","DOI":"10.1029\/2009JC005558"},{"key":"ref_10","unstructured":"Gommenginger, C., Cipollini, P., Snaith, H., West, L., and Passaro, M. (2013, January 26\u201327). SAR altimetry over the open and coastal ocean: Status and Open issues. Proceedings of the Ocean SAR Altimetry Expert Group Meeting, Southampton, UK. Available online: http:\/\/www.satoc.eu\/projects\/CP4O\/docs\/SARALT_EG_pdfs\/cg1_CP4O_SARExpert_2627June2013.pdf."},{"key":"ref_11","unstructured":"Gommenginger, C., Martin-Puig, C., Amarouche, L., and Raney, R.K. (2013). Review of State of Knowledge for SAR Altimetry over Ocean. Report of the EUMETSAT JASON-CS SAR Mode Error Budget Study, National Oceanography Centre. EUMETSAT Reference, EUM\/RSP\/REP\/14\/749304, Version 2.2."},{"key":"ref_12","unstructured":"Ouwehand, L. (2013, January 12\u201314). Sensitivity of SAR Mode Altimeter to Swell Effect. Proceedings of the CryoSat Third User Workshop, Dresden, Germany."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1402","DOI":"10.1093\/gji\/ggt469","article-title":"Retracking CryoSat-2, Envisat and Jason-1 radar altimetry waveforms for improved gravity field recovery","volume":"196","author":"Garcia","year":"2014","journal-title":"Geophys. J. Int."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1109\/TGRS.2012.2200298","article-title":"Calibration of the CryoSat-2 Interferometer and Measurement of Across-Track Ocean Slope","volume":"51","author":"Galin","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2641","DOI":"10.1016\/j.asr.2015.02.014","article-title":"The German Bight: A validation of CryoSat-2 altimeter data in SAR mode","volume":"55","author":"Dinardo","year":"2015","journal-title":"Adv. Space Res."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Dinardo, S., Fenoglio-Marc, L., Buchhaupt, C., Becker, M., Scharro, R., Fernandes, M.J., and Benveniste, J. (2017). Coastal SAR and PLRM altimetry in German Bight and West Baltic Sea. Adv. Space Res.","DOI":"10.1016\/j.asr.2017.12.018"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Buchhaupt, C., Fenoglio-Marc, L., Dinardo, S., Scharroo, R., and Becker, M. (2017). A fast convolution based waveform modell for conventional and unfocused SAR altimetry. Adv. Space Res.","DOI":"10.1016\/j.asr.2017.11.039"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"130","DOI":"10.2112\/JCOASTRES-D-12-00239.1","article-title":"Remote Sensing of Small-Scale Storm Variations in Coastal Seas","volume":"30","author":"Reale","year":"2014","journal-title":"J. Coast. Res."},{"key":"ref_19","unstructured":"Lacoste, H., and Ouwehand, L. (2006, January 23\u201326). Numerical Pseudo-Random Simulation of SAR Sea and Wind Response. Proceedings of the Advances in SAR Oceanography from Envisat and ERS Missions (SEASAR 2006), Frascati, Italy."},{"key":"ref_20","unstructured":"Ouwehand, L. (December, January 29). Sea Wave Numerical Simulations and Verification in Tyrrhenian Costal Area with X-Band Cosmo-Skymed SAR Data. Proceedings of the ESA, SOLAS & EGU Joint Conference \u201cEarth Observation for Ocean-Atmosphere Interactions Science\u201d, Frascati, Italy."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/7\/1100\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:11:30Z","timestamp":1760195490000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/7\/1100"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,7,10]]},"references-count":20,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2018,7]]}},"alternative-id":["rs10071100"],"URL":"https:\/\/doi.org\/10.3390\/rs10071100","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,7,10]]}}}