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In this study, we use Idai, one of the deadliest TCs on record in the Southern Hemisphere, as an example. Dual-polarization synthetic aperture radar (SAR) measurements from the Copernicus Sentinel-1 mission are used to examine the TC structure and intensity. The wind speed is estimated and compared using well known C-band model functions based on calibrated cross-polarization SAR images. Because of the relatively high noise floor of the Sentinel-1 data, wind speeds under 20 m\/s from cross-polarization models are ignored and replaced by low to moderate wind speeds retrieved from co-polarization radar signals. Wind fields retrieved from the co- and cross-polarization model results are then merged together to estimate the TC size and the TC fullness scale, a concept related to the wind structure of a storm. Idai has a very strong wind speed and fullness structure, indicating that it was indeed a very intense storm. The approach demonstrates that open and freely available Sentinel-1 SAR data is a unique dataset to estimate the potential destructiveness of similar natural disasters like Idai.<\/jats:p>","DOI":"10.3390\/rs11232837","type":"journal-article","created":{"date-parts":[[2019,11,29]],"date-time":"2019-11-29T10:58:21Z","timestamp":1575025101000},"page":"2837","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["A Study of the Intensity of Tropical Cyclone Idai Using Dual-Polarization Sentinel-1 Data"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9672-617X","authenticated-orcid":false,"given":"Peng","family":"Yu","sequence":"first","affiliation":[{"name":"State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China"},{"name":"College of Computer and Information Engineering, Xiamen University of Technology, Xiamen 361024, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Johnny A.","family":"Johannessen","sequence":"additional","affiliation":[{"name":"Nansen Environmental and Remote Sensing Research Center and Geophysical Institute, University of Bergen, N-5006 Bergen, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6578-6970","authenticated-orcid":false,"given":"Xiao-Hai","family":"Yan","sequence":"additional","affiliation":[{"name":"Center for Remote Sensing, College of Earth, Ocean and Environment, University of Delaware, Newark, DE 19716, USA"},{"name":"Joint Institute for Coastal Research and Management (Joint-CRM), University of Delaware\/Xiamen University, USA\/China. Newark, DE 19716, USA\/Xiang-An, Xiamen 361005, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4935-2838","authenticated-orcid":false,"given":"Xupu","family":"Geng","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China"},{"name":"Joint Institute for Coastal Research and Management (Joint-CRM), University of Delaware\/Xiamen University, USA\/China. Newark, DE 19716, USA\/Xiang-An, Xiamen 361005, China"},{"name":"Fujian Engineering Research Center for Ocean Remote Sensing Big Data, Xiamen 361005, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaojing","family":"Zhong","sequence":"additional","affiliation":[{"name":"College of Harbour and Environmental Engineering, Jimei University, Xiamen 361021, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lin","family":"Zhu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China"},{"name":"Joint Institute for Coastal Research and Management (Joint-CRM), University of Delaware\/Xiamen University, USA\/China. Newark, DE 19716, USA\/Xiang-An, Xiamen 361005, China"},{"name":"Fujian Engineering Research Center for Ocean Remote Sensing Big Data, Xiamen 361005, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,11,29]]},"reference":[{"key":"ref_1","unstructured":"(2019, September 02). Mozambique Cyclone Idai: Four Months After. Available online: https:\/\/reliefweb.int\/report\/mozambique\/mozambique-cyclone-idai-four-months-after-enpt."},{"key":"ref_2","unstructured":"(2019, June 27). Zimbabwe: Emergency Situation Report No. 9, As of 6 June 2019. Available online: https:\/\/reliefweb.int\/report\/zimbabwe\/zimbabwe-emergency-situation-report-no-9-6-june-2019."},{"key":"ref_3","unstructured":"(2019, April 04). Southern Africa: Cyclone Idai Snapshot (as of 12 March 2019). 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