{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T01:03:27Z","timestamp":1776387807603,"version":"3.51.2"},"reference-count":41,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,3,31]],"date-time":"2021-03-31T00:00:00Z","timestamp":1617148800000},"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":["41574138, 41274149, and 41604139"],"award-info":[{"award-number":["41574138, 41274149, and 41604139"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"China Postdoctoral Science Foundation funded project","award":["2020M682163"],"award-info":[{"award-number":["2020M682163"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The Sporadic-E (Es) layer is an often-observed phenomenon at high latitudes; however, our understanding of the polar cap Es layer is severely limited due to the scarce number of measurements. Here, the first comprehensive study of the polar cap Es layer associated with Global Positioning System (GPS) Total Electron Content (TEC) variations and scintillations is presented with multiple measurements at Resolute, Canada (Canadian Advanced Digital Ionosonde (CADI), Northward-looking face of Resolute Incoherent-Scatter Radar (RISR-N), and GPS receiver). According to the joint observations, the polar cap Es layer is a thin patch structure with variously high electron density, which gradually develops into the lower E region (~100 km) and horizontally extends &gt;200 km. Moreover, the TEC variations produced by the polar cap Es layer are pulse-like enhancements with a general amplitude of ~0.5 TECu and are followed by smaller but rapid TEC perturbations. Furthermore, the possible scintillation effects likely associated with the polar cap Es layer are also discussed. As a consequence, the results widely expand our understanding on the polar cap Es layer, in particular on TEC variations.<\/jats:p>","DOI":"10.3390\/rs13071324","type":"journal-article","created":{"date-parts":[[2021,3,31]],"date-time":"2021-03-31T05:57:18Z","timestamp":1617170238000},"page":"1324","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["A Case Study of Polar Cap Sporadic-E Layer Associated with TEC Variations"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5853-8036","authenticated-orcid":false,"given":"Yong","family":"Wang","sequence":"first","affiliation":[{"name":"Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"},{"name":"Physics Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6566-708X","authenticated-orcid":false,"given":"Periyadan T.","family":"Jayachandran","sequence":"additional","affiliation":[{"name":"Physics Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada"}]},{"given":"David R.","family":"Themens","sequence":"additional","affiliation":[{"name":"Physics Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada"},{"name":"Space Environment and Radio Engineering Group (SERENE), School of Engineering, University of Birmingham, Birmingham B15 2TT, UK"}]},{"given":"Anthony M.","family":"McCaffrey","sequence":"additional","affiliation":[{"name":"Physics Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada"}]},{"given":"Qing-He","family":"Zhang","sequence":"additional","affiliation":[{"name":"Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai 264209, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7331-8461","authenticated-orcid":false,"given":"Shiva","family":"David","sequence":"additional","affiliation":[{"name":"Physics Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada"}]},{"given":"Richard","family":"Chadwick","sequence":"additional","affiliation":[{"name":"Physics Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1029\/RS007i003p00385","article-title":"Theory of midlatitude Sporadic E","volume":"7","author":"Layzer","year":"1975","journal-title":"Radio Sci."},{"key":"ref_2","unstructured":"Narcisi, R.S. 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