{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T05:00:21Z","timestamp":1790226021872,"version":"4.1.0"},"reference-count":34,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T00:00:00Z","timestamp":1789776000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Science and Higher Education of the Republic of Kazakhstan","award":["grant number AP26104545"],"award-info":[{"award-number":["grant number AP26104545"]}],"id":[{"id":"https:\/\/ror.org\/05tyne317","id-type":"ROR","asserted-by":"crossref"}]},{"award":["grant number AP26104545"],"award-info":[{"award-number":["grant number AP26104545"]}],"id":[{"id":"https:\/\/ror.org\/05tyne317","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We present observations of the ionospheric response to the severe geomagnetic storm of 19\u201321 January 2026, obtained using a Digisonde DPS-4D and GPS-based vertical Total Electron Content (TEC) measurements over Almaty, Kazakhstan. Solar wind parameters, geomagnetic indices (AE and SYM-H), and Interplanetary Magnetic Field (IMF) components were analyzed to characterize the storm drivers. The ionospheric response to the geomagnetic storm of 12\u201313 November 2025 was additionally analyzed to provide an overall picture of the ionospheric effects within the specified latitude\u2013longitude region. The evolution of the ionospheric disturbances revealed highly complex processes. The critical frequency and total electron content during the severe geomagnetic storms exhibited morphological similarities, reflecting a general response to geomagnetic storms, as well as notable differences in their storm-time responses and in the observed percentage deviations of foF2 and TEC relative to reference-day baselines. A combined observational approach provides a more complete picture of the ionospheric response during extreme space weather events.<\/jats:p>","DOI":"10.3390\/s26185935","type":"journal-article","created":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T10:21:48Z","timestamp":1790072508000},"page":"5935","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Ionospheric Response to the Severe Geomagnetic Storm of 19\u201321 January 2026 over Almaty (Kazakhstan) According to the Digisonde and GPS Data"],"prefix":"10.3390","volume":"26","author":[{"given":"Galina","family":"Gordiyenko","sequence":"first","affiliation":[{"name":"Institute of the Ionosphere, Almaty 050020, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yurii","family":"Litvinov","sequence":"additional","affiliation":[{"name":"Institute of the Ionosphere, Almaty 050020, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Murat","family":"Zhiganbayev","sequence":"additional","affiliation":[{"name":"Institute of the Ionosphere, Almaty 050020, Kazakhstan"},{"name":"JSC \u201cAcademy of Civil Aviation\u201d, Almaty 050039, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valentina","family":"Grichshenko","sequence":"additional","affiliation":[{"name":"Institute of the Ionosphere, Almaty 050020, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9735-7820","authenticated-orcid":false,"given":"Serik","family":"Nurakynov","sequence":"additional","affiliation":[{"name":"Institute of the Ionosphere, Almaty 050020, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexey","family":"Andreyev","sequence":"additional","affiliation":[{"name":"Institute of the Ionosphere, Almaty 050020, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vlad","family":"Zhigalov","sequence":"additional","affiliation":[{"name":"Institute of the Ionosphere, Almaty 050020, Kazakhstan"},{"name":"Department of Electronics, Telecommunications and Space Technologies, Institute of Automation and Information Technologies, Satbayev University, Almaty 050013, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1016\/j.asr.2013.04.019","article-title":"Ionospheric F-region response to geomagnetic disturbances","volume":"52","author":"Danilov","year":"2013","journal-title":"Adv. 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