{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T23:25:33Z","timestamp":1779924333213,"version":"3.53.1"},"reference-count":40,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2019,7,18]],"date-time":"2019-07-18T00:00:00Z","timestamp":1563408000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41876201"],"award-info":[{"award-number":["41876201"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The accurate estimation of the upper layer thickness in a two-layer ocean is a crucial step in the retrieval of internal solitary wave (ISW) amplitude from synthetic aperture radar (SAR) data. In this paper, we present a method to derive the upper layer thickness and the consequent ISW amplitude by combining two consecutive SAR images with the extended Korteweg-de Vries (eKdV) equation. An ISW case observed twice by the Chinese C-band SAR GaoFen-3 (GF-3) and the German X-band SAR TerraSAR-X (TS-X) with a temporal interval of approximately 11 min in shallow water to the southeast of Hainan Island in the northwestern South China Sea was used to demonstrate the applicability of the method. Using the in situ measurements of temperature and salinity near the observed ISW, the proposed method yielded an ISW amplitude of \u22124.52 m, in close proximity to \u22125.66 \u00b1 1.24 m derived by applying the classic Korteweg\u2013de Vries (KdV) equation based on the continuously stratified theory. Moreover, the climatological dataset of the World Ocean Atlas 2013 (WOA13) was also used with the proposed method in the Hainan case, and the results showed that the method can still provide a reasonable estimate of ISW amplitude in shallow water even when in situ oceanic stratification measurements are absent. The application of our method to derive the ISW amplitude from consecutive SAR images seems highly promising with the increasing emergence of tandem satellites in orbits.<\/jats:p>","DOI":"10.3390\/rs11141706","type":"journal-article","created":{"date-parts":[[2019,7,19]],"date-time":"2019-07-19T03:14:41Z","timestamp":1563506081000},"page":"1706","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["Retrieval of Internal Solitary Wave Amplitude in Shallow Water by Tandem Spaceborne SAR"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7568-7757","authenticated-orcid":false,"given":"Tong","family":"Jia","sequence":"first","affiliation":[{"name":"Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5817-1676","authenticated-orcid":false,"given":"Jianjun","family":"Liang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5009-5413","authenticated-orcid":false,"given":"Xiao-Ming","family":"Li","sequence":"additional","affiliation":[{"name":"Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China"},{"name":"Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China"},{"name":"Hainan Key Laboratory of Earth Observation, Sanya 572029, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kaiguo","family":"Fan","sequence":"additional","affiliation":[{"name":"P.O. Box 5136, Haidian District, Beijing 100094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,7,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Magalhaes, J.M., and Da Silva, J.C.B. (2018). Internal solitary waves in the Andaman Sea: New insights from SAR imagery. Remote Sens., 10.","DOI":"10.3390\/rs10060861"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1625","DOI":"10.1175\/1520-0485(1985)015<1625:TSSISE>2.0.CO;2","article-title":"The Sulu Sea internal soliton experiment","volume":"15","author":"Apel","year":"1985","journal-title":"J. Phys. Oceanogr."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Liang, J., Li, X.-M., Sha, J., Jia, T., and Ren, Y. (2019). The lifecycle of nonlinear internal waves in the northwestern South China Sea. J. Phys. 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