{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:39:24Z","timestamp":1760240364229,"version":"build-2065373602"},"reference-count":56,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2019,5,20]],"date-time":"2019-05-20T00:00:00Z","timestamp":1558310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2016YFA0600102"],"award-info":[{"award-number":["2016YFA0600102"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Nature Science Foundation of China","award":["41306193"],"award-info":[{"award-number":["41306193"]}]},{"name":"Ministry of Science and Technology of China and the European Space Agency through the Dragon-4 Programme","award":["32292"],"award-info":[{"award-number":["32292"]}]},{"DOI":"10.13039\/501100017669","name":"Basic Scientific Fund for National Public Research Institutes of China","doi-asserted-by":"publisher","award":["2014G31"],"award-info":[{"award-number":["2014G31"]}],"id":[{"id":"10.13039\/501100017669","id-type":"DOI","asserted-by":"publisher"}]},{"name":"KAMON project funded by the Academy of Finland","award":["283034"],"award-info":[{"award-number":["283034"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>A new method called B\u00e9zier curve fitting (BCF) for approximating CryoSat-2 (CS-2) SAR-mode waveform is developed to optimize the retrieval of surface elevation of both sea ice and leads for the period of late winter\/early spring. We found that the best results are achieved when the retracking points are fixed on positions at which the rise of the fitted B\u00e9zier curve reaches 70% of its peak in case of leads, and 50% in case of sea ice. In order to evaluate the proposed retracking algorithm, we compare it to other empirically-based methods currently reported in the literature, namely the threshold first-maximum retracker algorithm (TFMRA) and the European Space Agency (ESA) CS-2 in-depth Level-2 algorithm (L2I). The results of the retracking procedure for the different algorithms are validated using data of the Operation Ice Bridge (OIB) airborne mission. For two OIB campaign periods in March 2015 and April 2016, the mean absolute differences between freeboard values retrieved from CS-2 and OIB data were 9.22 and 7.79 cm when using the BCF method, 10.41 cm and 8.16 cm for TFMRA, and 10.01 cm and 8.42 cm for L2I. This suggests that the sea ice freeboard data can be obtained with a higher accuracy when using the proposed BCF method instead of the TFMRA or the CS-2 L2I algorithm.<\/jats:p>","DOI":"10.3390\/rs11101194","type":"journal-article","created":{"date-parts":[[2019,5,20]],"date-time":"2019-05-20T11:05:07Z","timestamp":1558350307000},"page":"1194","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["A New Retracking Algorithm for Retrieving Sea Ice Freeboard from CryoSat-2 Radar Altimeter Data during Winter\u2013Spring Transition"],"prefix":"10.3390","volume":"11","author":[{"given":"Xiaoyi","family":"Shen","sequence":"first","affiliation":[{"name":"Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Collaborative Innovation Center of South China Sea Studies, Nanjing University, Nanjing 210023, China"},{"name":"First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4799-0446","authenticated-orcid":false,"given":"Markku","family":"Simil\u00e4","sequence":"additional","affiliation":[{"name":"Finnish Meteorological Institute, Marine Research, 00101 Helsinki, Finland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5031-648X","authenticated-orcid":false,"given":"Wolfgang","family":"Dierking","sequence":"additional","affiliation":[{"name":"The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 27570 Bremerhaven, Germany"},{"name":"Center for Integrated Remote Sensing and Forecasting for Arctic Operations, Arctic University of Norway, 9019 Troms\u00f8, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xi","family":"Zhang","sequence":"additional","affiliation":[{"name":"First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, China"},{"name":"Ocean Telemetry Technology Innovation Center, Ministry of Natural Resources of China, Qingdao 266061, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0212-4069","authenticated-orcid":false,"given":"Changqing","family":"Ke","sequence":"additional","affiliation":[{"name":"Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Collaborative Innovation Center of South China Sea Studies, Nanjing University, Nanjing 210023, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Meijie","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Physics, University of Qingdao, Qingdao 266071, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manman","family":"Wang","sequence":"additional","affiliation":[{"name":"Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Collaborative Innovation Center of South China Sea Studies, Nanjing University, Nanjing 210023, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,5,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"285","DOI":"10.3189\/2015JoG14J157","article-title":"Evaluation of CryoSat-2 derived sea-ice freeboard over fast ice in McMurdo Sound, Antarctica","volume":"61","author":"Price","year":"2015","journal-title":"J. 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