{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,6]],"date-time":"2025-12-06T17:19:20Z","timestamp":1765041560748,"version":"build-2065373602"},"reference-count":33,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2024,7,20]],"date-time":"2024-07-20T00:00:00Z","timestamp":1721433600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"MUR","award":["CUP D53J19000170001"],"award-info":[{"award-number":["CUP D53J19000170001"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Ground-based ionospheric, CHAMP\/STAR, and GOCE satellite neutral density \u03c1 observations under deep solar minimum conditions were used to find whether there is a dependence of longitudinal variations on polar vortex strength. Ionospheric stations at fixed-dipole geomagnetic \u03a6 \u2248 38\u00b0 and geographic \u03c6 \u2248 40\u00b0N latitudes located in \u2018near-pole\u2019 and \u2018far-from-pole\u2019 longitudinal sectors were used in the analysis. No significant longitudinal NmF2 (electron concentration in the F2-layer maximum) dependence on the polar vortex strength was revealed. Geomagnetic control was shown to be responsible for the observed longitudinal NmF2 variations. Satellite-observed longitudinal variations in neutral density did not show any visible reaction to the polar vortex strength. However, the impact of sudden stratospheric warming (SSW) on the upper atmosphere is strong enough to change the neutral density longitudinal distribution. The impact of SSW shows a global occurrence and \u2018works\u2019 within 3\u20135 days in geographic coordinates in the vicinity of the SSW peak. Atomic oxygen values retrieved under \u2018strong\u2019 and \u2018weak\u2019 polar vortex strengths confirm the results obtained on longitudinal variations in NmF2 and \u03c1. In conclusion, no visible effects related to \u2018strong\u2019 or \u2018weak\u2019 polar vortex strengths have been revealed in either NmF2 or satellite neutral density longitudinal variations. Alternatively, such effects may be very small and therefore cannot be confirmed experimentally.<\/jats:p>","DOI":"10.3390\/rs16142652","type":"journal-article","created":{"date-parts":[[2024,7,22]],"date-time":"2024-07-22T12:20:38Z","timestamp":1721650838000},"page":"2652","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["The Impact of Polar Vortex Strength on the Longitudinal Structure of the Noontime Mid-Latitude Ionosphere and Thermosphere"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4335-0345","authenticated-orcid":false,"given":"Loredana","family":"Perrone","sequence":"first","affiliation":[{"name":"Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy"}]},{"given":"Andrey","family":"Mikhailov","sequence":"additional","affiliation":[{"name":"Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN), Troitsk, 108840 Moscow, Russia"}]}],"member":"1968","published-online":{"date-parts":[[2024,7,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2871","DOI":"10.1029\/JA077i016p02871","article-title":"Longitudinal variations of thermospheric composition indicating magnetic control of polar heat input","volume":"77","author":"Hedin","year":"1972","journal-title":"J. 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