{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:16:44Z","timestamp":1760188604671,"version":"build-2065373602"},"reference-count":12,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2019,5,29]],"date-time":"2019-05-29T00:00:00Z","timestamp":1559088000000},"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>Waveforms of radar altimeters are often corrupted due to heterogeneous sea surface roughness within footprints, such as slicks. In past studies, subwaveform retrackers such as the adaptive leading edge subwaveform retracker (ALES) which use only a section of the waveform have been proposed. However, it is difficult to choose a reasonable estimation window from an individual waveform. In the present study, a post-processed subwaveform retracker is proposed which identifies the waveforms of surrounding along-track points. The size of the estimation window is variable and is determined to keep the sea surface roughness within the corresponding footprint homogeneous. The method was applied to seven years of 20 Hz Jason-2 altimeter data over the slick-rich Sulawesi Sea of Indonesia and compared with ALES and sensor geophysical data record (SGDR) products. The standard deviation of the sea surface dynamic heights was around 0.13 m, even without spatial smoothing or some geophysical corrections. This is only 75% and 25% of the ALES and SGDR results, respectively. Moreover, all retrievals of the range, SWH, and sigma0 include less outliers than the other products. These results indicate that the variable estimation windows determined in the present study can adapt well to the variation of sea surface roughness.<\/jats:p>","DOI":"10.3390\/rs11111274","type":"journal-article","created":{"date-parts":[[2019,5,29]],"date-time":"2019-05-29T11:31:28Z","timestamp":1559129488000},"page":"1274","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Coastal Waveform Retracking in the Slick-Rich Sulawesi Sea of Indonesia, Based on Variable Footprint Size with Homogeneous Sea Surface Roughness"],"prefix":"10.3390","volume":"11","author":[{"given":"Xifeng","family":"Wang","sequence":"first","affiliation":[{"name":"School of Marine Science and Environment Engineering, Dalian Ocean University, Dalian 116023, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2980-155X","authenticated-orcid":false,"given":"Kaoru","family":"Ichikawa","sequence":"additional","affiliation":[{"name":"Research Institute for Applied Mechanics, Kyushu University, Fukuoka 8168580, Japan"}]},{"given":"Dongni","family":"Wei","sequence":"additional","affiliation":[{"name":"Dalian Marine Environmental Monitoring Station of Chinese State Oceanic Administration, Dalian 116015, China"}]}],"member":"1968","published-online":{"date-parts":[[2019,5,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1109\/TAP.1977.1141536","article-title":"The average impulse response of a rough surface and its applications","volume":"25","author":"Brown","year":"1977","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"687","DOI":"10.1109\/TAP.1980.1142398","article-title":"Radar altimeter mean return waveforms from near-normal-incidence Ocean surface scattering","volume":"28","author":"Hayne","year":"1980","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Gommenginger, C., Thibaut, P., Fenoglio-Marc, L., Quartly, G., Deng, X., Gomez-Enri, J., Challenor, P., and Gao, Y. (2011). Retracking Altimeter Waveforms Near the Coasts. A Review of Retracking Methods and Some Applications to Coastal Waveforms. Coastal Altimetry, Springer.","DOI":"10.1007\/978-3-642-12796-0_4"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"474","DOI":"10.1109\/LGRS.2009.2039193","article-title":"Modeling Envisat RA-2 waveforms in the coastal zone: Case study of calm water contamination","volume":"7","author":"Vignudelli","year":"2010","journal-title":"IEEE J. Geosci. Remote Sens. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1143","DOI":"10.1175\/JTECH2030.1","article-title":"Signature of lighthouses, ships, and small islands in altimeter waveforms","volume":"24","author":"Tournadre","year":"2007","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_6","unstructured":"Thibaut, P., Ferreira, F., and Femenias, P. (2007, January 23\u201327). Sigma0 blooms in the Envisat radar altimeter data. Proceedings of the Envisat Symposium 2007, Montreux, Switzerland."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1016\/j.pnsc.2008.06.017","article-title":"Improved retracking algorithm for oceanic altimeter waveforms","volume":"19","author":"Bao","year":"2009","journal-title":"Prog. Nat. 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Remote Sens., 9.","DOI":"10.3390\/rs9070762"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1175\/1520-0426(1998)015<0387:DORCCF>2.0.CO;2","article-title":"Determination of rain cell characteristics from the analysis of TOPEX altimeter echo waveforms","volume":"15","author":"Tournadre","year":"1998","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_12","unstructured":"(2015). OSTM\/Jason-2 Products Handbook, Le site du Centre national d\u2019\u00e9tudes spatiales (CNES)."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/11\/1274\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:54:25Z","timestamp":1760187265000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/11\/1274"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,5,29]]},"references-count":12,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2019,6]]}},"alternative-id":["rs11111274"],"URL":"https:\/\/doi.org\/10.3390\/rs11111274","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2019,5,29]]}}}