{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:55:41Z","timestamp":1760147741228,"version":"build-2065373602"},"reference-count":24,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2023,2,27]],"date-time":"2023-02-27T00:00:00Z","timestamp":1677456000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Republic of Cyprus and the European Regional Development Fund","award":["BILATERAL\/RUSSIA (RFBR)\/1118\/0004"],"award-info":[{"award-number":["BILATERAL\/RUSSIA (RFBR)\/1118\/0004"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Using the topside electron density (Ne) measurements recorded over Cyprus and Russia, we investigate the latitudinal variation in the topside electron density during the interval 2014\u20132020, encompassing a period of high-to-low solar activity. The selected topside electron density dataset employed in this study is based on the in situ Langmuir probe data on board the European Space Agency (ESA) Swarm satellites, in the vicinity of the three Digisonde stations in Nicosia (35.14\u00b0N, 33.2\u00b0E), Moscow (55.5\u00b0N, 37.3\u00b0E) and Saint Petersburg (60.0\u00b0N, 30.7\u00b0E). Our investigation demonstrates that the ratio Ne_Swarm\/NmF2 between the coincident Ne_Swarm and the Digisonde NmF2 observations is higher than one on various occasions over Nicosia during the nighttime, which is not the case over Moscow and Saint Petersburg, signifying a discrepancy feature of the electron density at Swarm altitudes which depends not only on the solar activity and time of day but also on the latitude.<\/jats:p>","DOI":"10.3390\/rs15051344","type":"journal-article","created":{"date-parts":[[2023,3,1]],"date-time":"2023-03-01T03:57:49Z","timestamp":1677643069000},"page":"1344","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Investigation of the Topside Ionosphere over Cyprus and Russia Using Swarm Data"],"prefix":"10.3390","volume":"15","author":[{"given":"Haris","family":"Haralambous","sequence":"first","affiliation":[{"name":"Frederick Research Center, Nicosia 1303, Cyprus"},{"name":"Department of Electrical Engineering, Computer Engineering and Informatics, School of Engineering, Frederick University, Nicosia 1036, Cyprus"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3152-0055","authenticated-orcid":false,"given":"Krishnendu Sekhar","family":"Paul","sequence":"additional","affiliation":[{"name":"Frederick Research Center, Nicosia 1303, Cyprus"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8610-7236","authenticated-orcid":false,"given":"Arun Kumar","family":"Singh","sequence":"additional","affiliation":[{"name":"CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032, India"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4756-6066","authenticated-orcid":false,"given":"Tamara","family":"Gulyaeva","sequence":"additional","affiliation":[{"name":"The Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation of the Russian Academy of Sciences (IZMIRAN), Moscow 108840, Russia"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"RS0A04","DOI":"10.1029\/2008RS004036","article-title":"New satellite mission with old data: Rescuing a unique data set","volume":"44","author":"Benson","year":"2009","journal-title":"Radio Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1699","DOI":"10.1029\/2002GL014738","article-title":"Sounding of the topside ionosphere\/plasmasphere based on GPS measurements from CHAMP: Initial results","volume":"29","author":"Heise","year":"2002","journal-title":"Geophys. 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