{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:15:51Z","timestamp":1760242551724,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2017,11,18]],"date-time":"2017-11-18T00:00:00Z","timestamp":1510963200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100016693","name":"Ocean Public Welfare Scientific Research Project","doi-asserted-by":"publisher","award":["201205032-3"],"award-info":[{"award-number":["201205032-3"]}],"id":[{"id":"10.13039\/100016693","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Special Program for Key Scientific Instrument and Equipment Development of China","award":["2013YQ160793"],"award-info":[{"award-number":["2013YQ160793"]}]},{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"publisher","award":["2042016kf0019"],"award-info":[{"award-number":["2042016kf0019"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Second-order scattering based wave height measurement with high-frequency (HF) radar has always been subjected to problems such as distance limitation and external interference especially under low or moderate sea state. The performance is further exacerbated for a compact system with small antennas. First-order Bragg scattering has been investigated to relate wave height to the stronger Bragg backscatter, but calibrating the echo power along distance and direction is challenging. In this paper, a new method is presented to deal with the calibration and improve the Bragg scattering based wave height estimation from dual-frequency radar data. The relative difference of propagation attenuation and directional spreading between two operating frequencies has been found to be identifiable along range and almost independent of direction, and it is employed to effectively reduce the fitting requirements of in situ wave buoys. A 20-day experiment was performed over the Taiwan Strait of China to validate this method. Comparison of wave height measured by radar and buoys at distance of 15 km and 70 km shows that the root-mean-square errors are 0.34 m and 0.56 m, respectively, with correlation coefficient of 0.82 and 0.84.<\/jats:p>","DOI":"10.3390\/rs9111186","type":"journal-article","created":{"date-parts":[[2017,11,20]],"date-time":"2017-11-20T11:35:45Z","timestamp":1511177745000},"page":"1186","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Wave Height Estimation from First-Order Backscatter of a Dual-Frequency High Frequency Radar"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3450-3688","authenticated-orcid":false,"given":"Yingwei","family":"Tian","sequence":"first","affiliation":[{"name":"School of Electronic Information, Wuhan University, Wuhan 430072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Biyang","family":"Wen","sequence":"additional","affiliation":[{"name":"School of Electronic Information, Wuhan University, Wuhan 430072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3680-5903","authenticated-orcid":false,"given":"Hao","family":"Zhou","sequence":"additional","affiliation":[{"name":"School of Electronic Information, Wuhan University, Wuhan 430072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Caijun","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Electronic Information, Wuhan University, Wuhan 430072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jing","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Electronic Information, Wuhan University, Wuhan 430072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9622-5041","authenticated-orcid":false,"given":"Weimin","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Memorial University, St. John\u2019s, NL A1B 3X5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,11,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1109\/TAP.1972.1140123","article-title":"First-order theory and analysis of MF\/HF\/VHF scatter from the sea","volume":"AP-20","author":"Barrick","year":"1972","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/0034-4257(77)90004-9","article-title":"The ocean waveheight nondirectional spectrum from inversion of the HF sea-echo Doppler spectrum","volume":"6","author":"Barrick","year":"1977","journal-title":"Remote Sens. Environ."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1109\/JOE.2004.839929","article-title":"Directional wave information from the SeaSonde","volume":"30","author":"Lipa","year":"2005","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1109\/JOE.2006.886225","article-title":"An Empirical Method to Derive Ocean Waves From Second-Order Bragg Scattering: Prospects and Limitations","volume":"31","author":"Gurgel","year":"2006","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1651","DOI":"10.1175\/1520-0426(2000)017<1651:LTTIOH>2.0.CO;2","article-title":"Limits to the inversion of HF radar backscatter for ocean wave measurement","volume":"17","author":"Wyatt","year":"2000","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Wyatt, L.R. (2014, January 7\u201310). Wave measurements from the Australian Coastal Ocean Radar Network. Proceedings of the OCEANS 2014\u2014TAIPEI, Taipei, Taiwan.","DOI":"10.1109\/OCEANS-TAIPEI.2014.6964286"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1725","DOI":"10.1002\/2014JC010548","article-title":"Development of HF radar inversion algorithm for spectrum estimation (HIAS)","volume":"120","author":"Hisaki","year":"2015","journal-title":"J. Geophys. Res. Oceans"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1175\/JTECH1728.1","article-title":"Factors Affecting the Accuracy of SHOWEX HF Radar Wave Measurements","volume":"22","author":"Wyatt","year":"2005","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1007\/s10236-011-0465-9","article-title":"Wind-speed inversion from HF radar first-order backscatter signal","volume":"62","author":"Shen","year":"2012","journal-title":"Ocean Dyn."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1377","DOI":"10.1175\/JTECH-D-15-0242.1","article-title":"Remote Sensing of the Surface Wind Field over the Coastal Ocean via Direct Calibration of HF Radar Backscatter Power","volume":"33","author":"Kirincich","year":"2016","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2296","DOI":"10.1109\/LGRS.2015.2472976","article-title":"Wave Height Extraction From the First-Order Bragg Peaks in High-Frequency Radars","volume":"12","author":"Zhou","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1599","DOI":"10.1109\/LGRS.2014.2301837","article-title":"Measurement of High and Low Waves Using Dual-Frequency Broad-Beam HF Radar","volume":"11","author":"Tian","year":"2014","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Milsom, J.D. (1997, January 7\u201310). HF Groundwave Radar Equations. Proceedings of the Seventh International Conference on (Conf. Publ. No. 441) HF Radio Systems and Techniques, Nottingham, UK.","DOI":"10.1049\/cp:19970806"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3539","DOI":"10.1109\/TGRS.2010.2047022","article-title":"HFSW Radar Model: Simulation and Measurement","volume":"48","author":"Grosdidier","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1049\/ip-f-1.1983.0092","article-title":"Propagation and scattering in MF\/HF groundwave radar","volume":"130","author":"Shearman","year":"1983","journal-title":"IEE Proc. F Commun. Radar Signal Process."},{"key":"ref_16","unstructured":"Leong, H. (2012). On the Feasibility of Using Measured Sea Clutter Continuum In HFSWR to Validate Modelled Ground-Wave Propagation Attenuation in Rough Sea, Defence R&D Canada."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"517","DOI":"10.1029\/RS006i005p00517","article-title":"Theory of HF and VHF Propagation Across the Rough Sea, part I & II","volume":"6","author":"Barrick","year":"1971","journal-title":"Radio Sci."},{"key":"ref_18","first-page":"1","article-title":"Measurements of wind wave growth and swell decay during the Joint North Sea Wave Project (JONSWAP)","volume":"12","author":"Hasselmann","year":"1973","journal-title":"Dtsch. Hydrogr. Z"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"5181","DOI":"10.1029\/JZ069i024p05181","article-title":"A proposed spectral form for fully developed wind seas based upon the similarity theory of S.A. Kitaigorodskii","volume":"69","author":"Pierson","year":"1964","journal-title":"J. Geophys. Res."},{"key":"ref_20","unstructured":"Phillips, O.M. (1966). The Dynamics of the Upper Ocean, Cambridge University Press."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"680","DOI":"10.1109\/TAP.1973.1140557","article-title":"Mapping of North Atlantic winds by HF radar sea backscatter interpretation","volume":"21","author":"Long","year":"1973","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1029\/RS015i004p00843","article-title":"Methods for the extraction of long-period ocean wave parameters from narrow beam HF radar sea echo","volume":"15","author":"Lipa","year":"1980","journal-title":"Radio Sci."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Naderi, M., and P\u00e4tzold, M. (2015, January 19\u201322). Design and analysis of a one-dimensional sea surface simulator using the sum-of-sinusoids principle. Proceedings of the OCEANS 2015\u2014MTS\/IEEE Washington, Washington, DC, USA.","DOI":"10.23919\/OCEANS.2015.7404478"},{"key":"ref_24","first-page":"989","article-title":"Wave directional spectra from synthetic aperture observations of radio scatter","volume":"21","author":"Tyler","year":"1974","journal-title":"Deep Sea Res."},{"key":"ref_25","unstructured":"Codar (2017, September 27). SesSonde general specifications. Available online: http:\/\/www.codar.com\/images\/products\/SeaSonde\/1A-SeaSonde_v2_20100331.pdf."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1587\/elex.10.20130429","article-title":"A new fully-digital HF radar system for oceanographical remote sensing","volume":"10","author":"Tian","year":"2013","journal-title":"IEICE Electron. Express"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1363","DOI":"10.1175\/JTECH-D-13-00107.1","article-title":"Assessment of CODAR SeaSonde and WERA HF Radars in Mapping Surface Currents on the West Florida Shelf","volume":"31","author":"Liu","year":"2014","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1887","DOI":"10.1109\/LAWP.2017.2685181","article-title":"Design and Implementation of a Dual-Frequency Compact Antenna System for HF Radar","volume":"16","author":"Li","year":"2017","journal-title":"IEEE Antennas Wirel. Propag. Lett."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/11\/1186\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:50:11Z","timestamp":1760208611000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/11\/1186"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,11,18]]},"references-count":28,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2017,11]]}},"alternative-id":["rs9111186"],"URL":"https:\/\/doi.org\/10.3390\/rs9111186","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2017,11,18]]}}}