{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,14]],"date-time":"2026-01-14T15:30:14Z","timestamp":1768404614183,"version":"3.49.0"},"reference-count":35,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,15]],"date-time":"2022-01-15T00:00:00Z","timestamp":1642204800000},"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":["41722404"],"award-info":[{"award-number":["41722404"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Natural Science Foundation of Zhejiang Province","doi-asserted-by":"publisher","award":["LQ20D040001"],"award-info":[{"award-number":["LQ20D040001"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The Wuhan Ionospheric Oblique Backscatter Sounding System (WIOBSS) was applied as a bistatic radar to record the ionospheric E-region responses to a solar eclipse on 22 July 2009. The transmitter was located in Wuhan and the receiver was located in Huaian. The receiver observed anomalous echoes with larger Doppler shifts at the farther ranges compared with the echoes reflected by Es. According to the simulated ray propagation paths of the reflected and scattered waves, we considered that the anomalous echoes were scattered by E-region field-aligned irregularities (FAIs). The locations of the FAIs recorded by the WIOBSS were estimated with the International Geomagnetic Reference Field (IGRF) and the observed propagation parameters. These irregularities occurred at around the eclipse maximum and lasted for ~20\u201340 min. The steep plasma density gradient induced by the fast drop photo ionization under the lunar shadow was beneficial to the occurrence of gradient drift instability to generate the FAIs. They were different from the gravity wave-induced irregularities occurring in the recovery phase of the solar eclipse.<\/jats:p>","DOI":"10.3390\/rs14020392","type":"journal-article","created":{"date-parts":[[2022,1,16]],"date-time":"2022-01-16T20:45:21Z","timestamp":1642365921000},"page":"392","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["E-Region Field-Aligned Irregularities in the Middle of a Solar Eclipse Observed by a Bistatic Radar"],"prefix":"10.3390","volume":"14","author":[{"given":"Lei","family":"Qiao","sequence":"first","affiliation":[{"name":"Communication Engineering School, Hangzhou Dianzi University, Hangzhou 310018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6690-4024","authenticated-orcid":false,"given":"Gang","family":"Chen","sequence":"additional","affiliation":[{"name":"Electronic Information School, Wuhan University, Wuhan 430072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wanlin","family":"Gong","sequence":"additional","affiliation":[{"name":"Electronic Information School, Wuhan University, Wuhan 430072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xuesi","family":"Cai","sequence":"additional","affiliation":[{"name":"Communication Engineering School, Hangzhou Dianzi University, Hangzhou 310018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Erxiao","family":"Liu","sequence":"additional","affiliation":[{"name":"Communication Engineering School, Hangzhou Dianzi University, Hangzhou 310018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mingkun","family":"Su","sequence":"additional","affiliation":[{"name":"Communication Engineering School, Hangzhou Dianzi University, Hangzhou 310018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xuyang","family":"Teng","sequence":"additional","affiliation":[{"name":"Communication Engineering School, Hangzhou Dianzi University, Hangzhou 310018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhaoyang","family":"Qiu","sequence":"additional","affiliation":[{"name":"Communication Engineering School, Hangzhou Dianzi University, Hangzhou 310018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huina","family":"Song","sequence":"additional","affiliation":[{"name":"Communication Engineering School, Hangzhou Dianzi University, Hangzhou 310018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,15]]},"reference":[{"key":"ref_1","first-page":"442","article-title":"Effect of the Solar Eclipse on the Ionosphere","volume":"132","author":"Mitra","year":"1933","journal-title":"Nat. Cell Biol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1038\/240030a0","article-title":"Atmospheric gravity waves to be expected from the solar eclipse of 30 June 1973","volume":"240","author":"Beer","year":"1972","journal-title":"Nature"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"260","DOI":"10.1029\/JA077i001p00260","article-title":"Solar-eclipse effect on sporadic-E ionization","volume":"77","author":"Datta","year":"1972","journal-title":"J. Geophys. Res."},{"key":"ref_4","first-page":"06301","article-title":"Latitudinal dependence of the ionospheric response to solar eclipse of 15 January 2010","volume":"116","author":"Chen","year":"2011","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1253","DOI":"10.1002\/2017GL076572","article-title":"Investigation of the Electron Density Variation During the 21 August 2017 Solar Eclipse","volume":"45","author":"Reinisch","year":"2018","journal-title":"Geophys. Res. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1029\/JA078i001p00320","article-title":"Solar eclipse effect on sporadic E ionization","volume":"78","author":"Datta","year":"1973","journal-title":"J. Geophys. Res."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1186\/BF03352023","article-title":"Ionospheric measurements during the total solar eclipse of 11 August 1999","volume":"59","author":"Chandra","year":"2007","journal-title":"Earth Planets Space"},{"key":"ref_8","first-page":"610","article-title":"Variation of Es during Solar Eclipses","volume":"176","author":"Stoffregen","year":"1955","journal-title":"Nat. Cell Biol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2145","DOI":"10.1016\/j.asr.2019.07.037","article-title":"Abnormal behaviour of sporadic E-layer during the total solar eclipse of 22 July 2009 near the crest of EIA over India","volume":"64","author":"Tiwari","year":"2019","journal-title":"Adv. Space Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1029\/2010GL042855","article-title":"Nighttime-like quasi periodic echoes induced by a partial solar eclipse","volume":"37","author":"Thampi","year":"2010","journal-title":"Geophys. Res. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1021","DOI":"10.3319\/TAO.2013.07.08.01(AA)","article-title":"Daytime E-Region Irregularities During the 22 July 2009 Solar Eclipse over Chung-Li (24.9\u00b0N, 121.2\u00b0E), a Moderate Mid-Latitude Station","volume":"24","author":"Brahmanandam","year":"2013","journal-title":"Terr. Atmos. Ocean. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1002\/2014JA020666","article-title":"Daytime E region field-aligned irregularities observed during a solar eclipse","volume":"119","author":"Chen","year":"2014","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"13105","DOI":"10.1029\/2009GL038669","article-title":"Solar eclipse-induced E-region plasma irregularities observed by the Gadanki radar","volume":"36","author":"Patra","year":"2009","journal-title":"Geophys. Res. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"05319","DOI":"10.1029\/2010JA016258","article-title":"Characteristics of 150 km echoes linked with solar eclipse and their implications to the echoing phenomenon","volume":"116","author":"Patra","year":"2011","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"748","DOI":"10.1109\/LGRS.2009.2024439","article-title":"The Wuhan Ionospheric Sounding Systems","volume":"6","author":"Chen","year":"2009","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"959","DOI":"10.1029\/93RS01373","article-title":"A 50-MHz radio Doppler experiment for midlatitude Eregion coherent backscatter studies: System description and first results","volume":"28","author":"Haldoupis","year":"1993","journal-title":"Radio Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1029\/95GL03585","article-title":"An explanation for type 1 radar echoes from the midlatitude E-region ionosphere","volume":"23","author":"Haldoupis","year":"1996","journal-title":"Geophys. Res. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1002\/2014RS005591","article-title":"A multistatic and multifrequency novel approach for specular meteor radars to improve wind meas-urements in the MLT region","volume":"50","author":"Stober","year":"2015","journal-title":"Radio Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"416","DOI":"10.1002\/rds.20047","article-title":"Development of a passive VHF radar system using software-defined radio for equatorial plasma instability studies","volume":"48","author":"Tuysuz","year":"2013","journal-title":"Radio Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"4082","DOI":"10.1109\/TGRS.2017.2687830","article-title":"Effects of the Equatorial Electrojet on FM-Based Passive Radar Systems","volume":"55","author":"Tuysuz","year":"2017","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1029\/RG018i002p00401","article-title":"Ionospheric irregularities","volume":"18","author":"Fejer","year":"1980","journal-title":"Rev. Geophys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"5291","DOI":"10.1029\/1999JA900415","article-title":"A thermal mechanism for generation of small-scale irregularities in the ionospheric E region","volume":"105","author":"Kagan","year":"2000","journal-title":"J. Geophys. Res."},{"key":"ref_23","first-page":"A09325","article-title":"Enhancement and HF Doppler observations of sporadic-E during the solar eclipse of 22 July 2009","volume":"115","author":"Chen","year":"2010","journal-title":"J. Geophys. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1216","DOI":"10.1111\/j.1365-246X.2010.04804.x","article-title":"International Geomagnetic Reference Field: The eleventh generation","volume":"183","author":"Finlay","year":"2010","journal-title":"Geophys. J. Int."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"8011","DOI":"10.1029\/JA091iA07p08011","article-title":"Radar Studies of Long-Wavelength Waves Associated with Mid-Latitude Sporadic E Layers","volume":"91","author":"Riggin","year":"1986","journal-title":"J. Geophys. Res."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1029\/93RS01511","article-title":"On the origin of quasi-periodic radar backscatter from midlatitude sporadic E","volume":"29","author":"Tsunoda","year":"1994","journal-title":"Radio Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"10071","DOI":"10.1029\/1999JA900105","article-title":"Spatial occurrence of decameter midlatitude E region backscatter","volume":"104","author":"Hussey","year":"1999","journal-title":"J. Geophys. Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1195","DOI":"10.1016\/0021-9169(73)90016-0","article-title":"Wave-like structures of large-scale equatorial spread-F irregularities","volume":"35","year":"1973","journal-title":"J. Atmospheric Terr. Phys."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"028088","DOI":"10.1029\/2020JA028088","article-title":"Height Dependency of Solar Eclipse Effects: The Ionospheric Perspective","volume":"125","author":"Verhulst","year":"2020","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"858","DOI":"10.1029\/JA086iA02p00858","article-title":"Gradient drift irregularities in mid-latitude sporadic","volume":"86","author":"Ecklund","year":"1981","journal-title":"J. Geophys. Res. Earth Surf."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1761","DOI":"10.1029\/98GL00932","article-title":"The SEEK (Sporadic-E Experiment over Kyushu) Campaign","volume":"25","author":"Fukao","year":"1998","journal-title":"Geophys. Res. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1155","DOI":"10.1029\/1999RS002296","article-title":"A possible mechanism for echo striation generation of radar backscatter from midlatitude sporadic","volume":"35","author":"Maruyama","year":"2000","journal-title":"Radio Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"179","DOI":"10.5636\/jgg.43.179","article-title":"Profiles of electron density in the lower ionosphere observed by the MU radar","volume":"43","author":"Zhang","year":"1991","journal-title":"J. Geomagn. Geoelectr."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"028986","DOI":"10.1029\/2020JA028986","article-title":"Disturbances in Sporadic-E During the Great Solar Eclipse of 21 August 2017","volume":"126","author":"Chen","year":"2021","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1029\/2004GL021275","article-title":"Incoherent scatter radar study of photochemistry in the E-region","volume":"32","author":"Zhou","year":"2005","journal-title":"Geophys. Res. Lett."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/2\/392\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T14:15:04Z","timestamp":1760364904000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/2\/392"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,1,15]]},"references-count":35,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["rs14020392"],"URL":"https:\/\/doi.org\/10.3390\/rs14020392","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,1,15]]}}}