{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T18:28:46Z","timestamp":1775068126767,"version":"3.50.1"},"reference-count":8,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2022,4,2]],"date-time":"2022-04-02T00:00:00Z","timestamp":1648857600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004569","name":"Ministry of Science and Higher Education","doi-asserted-by":"publisher","award":["6\/E-73\/SPUB\/SP\/2019"],"award-info":[{"award-number":["6\/E-73\/SPUB\/SP\/2019"]}],"id":[{"id":"10.13039\/501100004569","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The Earth\u2019s ionosphere is a highly variable medium on a wide range of spatio-temporal scales. The responsiveness of plasma to the geomagnetic field and its changes gives rise to anisotropy, which may introduce wave-like characteristics while scanning the ionosphere with a line-of-sight towards a radio source. Previous studies of LOw Frequency ARray (LOFAR) calibration phase solutions report that the estimated beta parameter of a structure function calculated over 6\u20138 h of astronomical observation timespan has a range of values from 1.6 to 2.0, with an average of 1.89. Such difference between the observations could result from transient wave-like disturbances within the data. This study aims to present a method of signal processing of ionospheric calibration datasets that allows the extraction of a transient wave-like signal and discuss its possible origin. We use complex Morlet wavelet analysis applied to two 8 h observations corresponding to very quiet geomagnetic conditions. We find a wave-like signal in the interferometric Total Electron Content data even during periods of no geomagnetic activity. We suggest it results from the relative velocity changes between the LOFAR line-of-sight and a convection pattern in the ionospheric F layer. Establishing the relationship between quiet time ionosphere, geomagnetic field changes and LOFAR\u2019s calibration solutions may prove beneficial to determination of the dominant signals in the more disturbed conditions, which we leave for future study.<\/jats:p>","DOI":"10.3390\/rs14071719","type":"journal-article","created":{"date-parts":[[2022,4,3]],"date-time":"2022-04-03T06:04:01Z","timestamp":1648965841000},"page":"1719","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Detection of Periodic Disturbances in LOFAR Calibration Solutions"],"prefix":"10.3390","volume":"14","author":[{"given":"Katarzyna","family":"Beser","sequence":"first","affiliation":[{"name":"Space Research Centre, PAS, 00-716 Warszawa, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3086-8455","authenticated-orcid":false,"given":"Maaijke","family":"Mevius","sequence":"additional","affiliation":[{"name":"ASTRON, 7991 PD Dwingeloo, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marcin","family":"Grzesiak","sequence":"additional","affiliation":[{"name":"Space Research Centre, PAS, 00-716 Warszawa, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hanna","family":"Rothkaehl","sequence":"additional","affiliation":[{"name":"Space Research Centre, PAS, 00-716 Warszawa, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1185","DOI":"10.1051\/0004-6361\/200811094","article-title":"Ionospheric Calibration of Low Frequency Radio Interferometric Observations using the Peeling Scheme: I. Method Description and First Results","volume":"501","author":"Intema","year":"2009","journal-title":"Astron. Astrophys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1016\/0032-0633(92)90163-I","article-title":"Wavenumber-resolved observations of ionospheric waves using the very large array radiotelescope","volume":"40","author":"Jacobson","year":"1992","journal-title":"Plant. Space Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3974","DOI":"10.1093\/mnras\/stx1797","article-title":"Characterisation of the ionosphere above the Murchison Radio Observatory using the Murchison Widefield Array","volume":"471","author":"Jordan","year":"2017","journal-title":"Mon. Notices R. Astron. Soc."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1002\/2015RS005711","article-title":"Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array","volume":"50","author":"Loi","year":"2015","journal-title":"Radio Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"927","DOI":"10.1002\/2016RS006028","article-title":"Probing ionospheric structures using the LOFAR radio telescope","volume":"51","author":"Mevius","year":"2016","journal-title":"Radio Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1002\/2017RS006263","article-title":"Pilot Ionosonde Network for Identification of Traveling Ionospheric Disturbances","volume":"53","author":"Reinisch","year":"2018","journal-title":"Radio Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s40623-020-01274-3","article-title":"Diagnosing low-\/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO","volume":"72","author":"Park","year":"2020","journal-title":"Earth Planets Space"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e2019JA027694","DOI":"10.1029\/2019JA027694","article-title":"Latitude Dependence of Interhemispheric Field-Aligned Currents (IHFACs) as Observed by the Swarm Constellation","volume":"125","author":"Park","year":"2020","journal-title":"J. Geophys. Res. Space Phys."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/7\/1719\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:48:57Z","timestamp":1760136537000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/7\/1719"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,2]]},"references-count":8,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2022,4]]}},"alternative-id":["rs14071719"],"URL":"https:\/\/doi.org\/10.3390\/rs14071719","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,2]]}}}