{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T00:42:09Z","timestamp":1775090529995,"version":"3.50.1"},"reference-count":46,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,2,12]],"date-time":"2023-02-12T00:00:00Z","timestamp":1676160000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["42188101"],"award-info":[{"award-number":["42188101"]}]},{"name":"National Natural Science Foundation of China","award":["42025404"],"award-info":[{"award-number":["42025404"]}]},{"name":"National Natural Science Foundation of China","award":["41874195"],"award-info":[{"award-number":["41874195"]}]},{"name":"National Natural Science Foundation of China","award":["42274205"],"award-info":[{"award-number":["42274205"]}]},{"name":"National Natural Science Foundation of China","award":["2022YFF0503700"],"award-info":[{"award-number":["2022YFF0503700"]}]},{"name":"National Natural Science Foundation of China","award":["XDB41000000"],"award-info":[{"award-number":["XDB41000000"]}]},{"name":"National Natural Science Foundation of China","award":["D020308"],"award-info":[{"award-number":["D020308"]}]},{"name":"National Natural Science Foundation of China","award":["D020104"],"award-info":[{"award-number":["D020104"]}]},{"name":"National Natural Science Foundation of China","award":["D020303"],"award-info":[{"award-number":["D020303"]}]},{"name":"National Natural Science Foundation of China","award":["220100051"],"award-info":[{"award-number":["220100051"]}]},{"name":"National Key R&amp;D Program of China","award":["42188101"],"award-info":[{"award-number":["42188101"]}]},{"name":"National Key R&amp;D Program of China","award":["42025404"],"award-info":[{"award-number":["42025404"]}]},{"name":"National Key R&amp;D Program of China","award":["41874195"],"award-info":[{"award-number":["41874195"]}]},{"name":"National Key R&amp;D Program of China","award":["42274205"],"award-info":[{"award-number":["42274205"]}]},{"name":"National Key R&amp;D Program of China","award":["2022YFF0503700"],"award-info":[{"award-number":["2022YFF0503700"]}]},{"name":"National Key R&amp;D Program of China","award":["XDB41000000"],"award-info":[{"award-number":["XDB41000000"]}]},{"name":"National Key R&amp;D Program of China","award":["D020308"],"award-info":[{"award-number":["D020308"]}]},{"name":"National Key R&amp;D Program of China","award":["D020104"],"award-info":[{"award-number":["D020104"]}]},{"name":"National Key R&amp;D Program of China","award":["D020303"],"award-info":[{"award-number":["D020303"]}]},{"name":"National Key R&amp;D Program of China","award":["220100051"],"award-info":[{"award-number":["220100051"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["42188101"],"award-info":[{"award-number":["42188101"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["42025404"],"award-info":[{"award-number":["42025404"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["41874195"],"award-info":[{"award-number":["41874195"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["42274205"],"award-info":[{"award-number":["42274205"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["2022YFF0503700"],"award-info":[{"award-number":["2022YFF0503700"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["XDB41000000"],"award-info":[{"award-number":["XDB41000000"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["D020308"],"award-info":[{"award-number":["D020308"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["D020104"],"award-info":[{"award-number":["D020104"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["D020303"],"award-info":[{"award-number":["D020303"]}]},{"name":"B-type Strategic Priority Program of the Chinese Academy of Sciences","award":["220100051"],"award-info":[{"award-number":["220100051"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["42188101"],"award-info":[{"award-number":["42188101"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["42025404"],"award-info":[{"award-number":["42025404"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["41874195"],"award-info":[{"award-number":["41874195"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["42274205"],"award-info":[{"award-number":["42274205"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["2022YFF0503700"],"award-info":[{"award-number":["2022YFF0503700"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["XDB41000000"],"award-info":[{"award-number":["XDB41000000"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["D020308"],"award-info":[{"award-number":["D020308"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["D020104"],"award-info":[{"award-number":["D020104"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["D020303"],"award-info":[{"award-number":["D020303"]}]},{"name":"Pre-research projects on Civil Aerospace Technologies","award":["220100051"],"award-info":[{"award-number":["220100051"]}]},{"name":"Hubei Luojia Laboratory","award":["42188101"],"award-info":[{"award-number":["42188101"]}]},{"name":"Hubei Luojia Laboratory","award":["42025404"],"award-info":[{"award-number":["42025404"]}]},{"name":"Hubei Luojia Laboratory","award":["41874195"],"award-info":[{"award-number":["41874195"]}]},{"name":"Hubei Luojia Laboratory","award":["42274205"],"award-info":[{"award-number":["42274205"]}]},{"name":"Hubei Luojia Laboratory","award":["2022YFF0503700"],"award-info":[{"award-number":["2022YFF0503700"]}]},{"name":"Hubei Luojia Laboratory","award":["XDB41000000"],"award-info":[{"award-number":["XDB41000000"]}]},{"name":"Hubei Luojia Laboratory","award":["D020308"],"award-info":[{"award-number":["D020308"]}]},{"name":"Hubei Luojia Laboratory","award":["D020104"],"award-info":[{"award-number":["D020104"]}]},{"name":"Hubei Luojia Laboratory","award":["D020303"],"award-info":[{"award-number":["D020303"]}]},{"name":"Hubei Luojia Laboratory","award":["220100051"],"award-info":[{"award-number":["220100051"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Solar flares have a severe impact on the near-earth space environment, during which the VLF signals observed by the ground-based instrument exhibit abnormal changes. However, the similarity and differences of VLF signal responses to solar flares over daytime and nighttime propagation paths are still unclear. Previous magnetograph measurements suggest that solar flares can also influence the dark hemisphere by the induction currents caused by the change in the ionospheric electrical conductivity of the sunlit hemisphere. To examine these effects, we have analyzed the solar flare effects on VLF propagation along two paths that are suited along the north\u2013south direction, but with a time difference of 12 h. From late March to late May in the year of 2022, a total of 32 flare events with clear VLF responses are selected in order to analyze the similarity and differences between daytime and nighttime propagation paths. Different from the previous magnetograph measurements, it is found that the solar flare effects can only be observed from daytime VLF propagation paths. Moreover, present results show that the amplitude and phase variation of the VLF signal increases almost linearly with the magnitude of solar flares, and the stronger the solar flare, the more obvious the influence on VLF signals. However, the two paths exhibit notably different sensitivity in terms of amplitude and phase variation to solar flare class. Future studies that aim at nowcasting solar flare events using ground-based VLF receivers need to take these effects into account. The goal is to better understand the effects of solar flares on the lower ionosphere, with a view toward improving the nowcasting capability of the VLF technique for solar flares.<\/jats:p>","DOI":"10.3390\/rs15041018","type":"journal-article","created":{"date-parts":[[2023,2,13]],"date-time":"2023-02-13T01:48:56Z","timestamp":1676252936000},"page":"1018","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["Comparison of VLF Signal Responses to Solar Flares along Daytime and Nighttime Propagation Paths"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3078-9562","authenticated-orcid":false,"given":"Xudong","family":"Gu","sequence":"first","affiliation":[{"name":"Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan 430072, China"}]},{"given":"Juan","family":"Yi","sequence":"additional","affiliation":[{"name":"Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan 430072, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0336-3849","authenticated-orcid":false,"given":"Shiwei","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan 430072, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2448-2094","authenticated-orcid":false,"given":"Zejun","family":"Hu","sequence":"additional","affiliation":[{"name":"MNR Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China"}]},{"given":"Wei","family":"Xu","sequence":"additional","affiliation":[{"name":"Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan 430072, China"},{"name":"Hubei Luojia Laboratory, Wuhan 430072, China"}]},{"given":"Binbin","family":"Ni","sequence":"additional","affiliation":[{"name":"Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan 430072, China"},{"name":"Hubei Luojia Laboratory, Wuhan 430072, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4009-7305","authenticated-orcid":false,"given":"Bin","family":"Li","sequence":"additional","affiliation":[{"name":"MNR Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China"}]},{"given":"Fang","family":"He","sequence":"additional","affiliation":[{"name":"MNR Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6325-5049","authenticated-orcid":false,"given":"Xiangcai","family":"Chen","sequence":"additional","affiliation":[{"name":"MNR Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China"}]},{"given":"Hongqiao","family":"Hu","sequence":"additional","affiliation":[{"name":"MNR Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1007\/s11214-010-9701-8","article-title":"An observational overview of solar flares","volume":"159","author":"Fletcher","year":"2011","journal-title":"Space Sci. Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e2019JA027431","DOI":"10.1029\/2019JA027431","article-title":"Responses of the thermosphere and ionosphere system to concurrent solar flares and geomagnetic storms","volume":"125","author":"Qian","year":"2020","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"A11317","DOI":"10.1029\/2011JA016961","article-title":"Ionospheric response to the x-class solar flare on 7 September 2005","volume":"116","author":"Xiong","year":"2011","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1088\/0004-637X\/759\/1\/71","article-title":"Global energetics of thirty-eight large solar eruptive events","volume":"759","author":"Emslie","year":"2012","journal-title":"Astrophys. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1705","DOI":"10.1029\/92JA01529","article-title":"A multiple-mode three-dimensional model of VLF propagation in the Earth-ionosphere waveguide in the presence of localized D region disturbances","volume":"98","author":"Poulsen","year":"1993","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"10224","DOI":"10.1029\/2018JA025992","article-title":"Response of Earth\u2019s Upper Atmosphere and VLF Propagation to Celestial X-Ray Ionization: Investigation With Monte Carlo Simulation and Long Wave Propagation Capability code","volume":"123","author":"Palit","year":"2018","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1109\/TGRS.2009.2028334","article-title":"Sensitive broadband ELF\/VLF radio reception with the AWESOME instrument","volume":"48","author":"Cohen","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5809","DOI":"10.1029\/JA073i017p05809-01","article-title":"Mode conversion and refraction effects in the Earth-ionosphere waveguide for VLF radio waves","volume":"73","author":"Wait","year":"1968","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1781","DOI":"10.1029\/98RS02381","article-title":"Ionospheric D region remote sensing using vlf radio atmospherics","volume":"33","author":"Cummer","year":"1998","journal-title":"Radio Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1729","DOI":"10.1016\/S1364-6826(01)00048-7","article-title":"Solar flare induced ionospheric D-region enhancements from VLF amplitude observations","volume":"63","author":"Thomson","year":"2001","journal-title":"J. Atmos. Sol.-Terr. Phys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"775","DOI":"10.1016\/j.jastp.2007.01.012","article-title":"D-region electron density evaluated from vlf amplitude time delay during x-ray solar flares","volume":"69","author":"Grubor","year":"2007","journal-title":"J. Atmos. Sol.-Terr. Phys."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"A00E36","DOI":"10.1029\/2009JA014775","article-title":"A survey of ELF and VLF research on lightning-ionosphere interactions and causative discharges","volume":"115","author":"Inan","year":"2010","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"A09313","DOI":"10.1029\/2010JA015355","article-title":"Daytime tropical D region parameters from short path VLF phase and amplitude","volume":"115","author":"Thomson","year":"2010","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"A11305","DOI":"10.1029\/2010JA016248","article-title":"Daytime D region parameters from long-path VLF phase and amplitude","volume":"116","author":"Thomson","year":"2011","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"e2021JA029288","DOI":"10.1029\/2021JA029288","article-title":"An electron density model of the d-and e-region ionosphere for transionospheric vlf propagation","volume":"126","author":"Xu","year":"2021","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s10509-013-1699-4","article-title":"Solar flare induced D-region ionospheric perturbations evaluated from VLF measurements","volume":"350","author":"Singh","year":"2014","journal-title":"Astrophys. Space Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/j.jastp.2014.12.009","article-title":"Solar flares induced D-region ionospheric and geomagnetic perturbations","volume":"123","author":"Selvakumaran","year":"2015","journal-title":"J. Atmos. Sol.-Terr. Phys."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1213","DOI":"10.1007\/s12648-018-1224-2","article-title":"Ionospheric response to an intense solar flare in equatorial and low latitude region","volume":"92","author":"Rathore","year":"2018","journal-title":"Indian J. Phys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.jastp.2003.09.009","article-title":"Solar flare induced ionospheric d-region enhancements from vlf phase and amplitude observations","volume":"66","author":"McRae","year":"2004","journal-title":"J. Atmos. Sol.-Terr. Phys."},{"key":"ref_20","first-page":"27","article-title":"Observation of the effects of solar flares on the NWC signal using the new VLF receiver at tay nguyen university","volume":"8","author":"Tan","year":"2014","journal-title":"Sun Geosph."},{"key":"ref_21","first-page":"1508","article-title":"Response characteristics of very low frequency signals from JJI transmitter to solar flare events","volume":"64","author":"Gu","year":"2021","journal-title":"Chin. J. Geohpys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1783","DOI":"10.1029\/2019SW002297","article-title":"Developing a Nowcasting Capability for X-Class Solar Flares Using VLF Radiowave Propagation Changes","volume":"17","author":"George","year":"2019","journal-title":"Space Weather."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e2021SW002820","DOI":"10.1029\/2021SW002820","article-title":"Solar flare X-ray impacts on long subionospheric VLF paths","volume":"19","author":"Belcher","year":"2021","journal-title":"Space Weather."},{"key":"ref_24","first-page":"45","article-title":"A comparative study of measured amplitude and phase perturbations of VLF and LF radio signals induced by solar flares","volume":"188","year":"2014","journal-title":"Serb. Astron. J."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"775","DOI":"10.1029\/94RS03190","article-title":"Ionospheric model validation at VLF and LF","volume":"30","author":"Ferguson","year":"1995","journal-title":"Radio Sci."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Palit, S., Basak, T., Pal, S., Mondal, S.K., and Chakrabarti, S.K. (2014, January 16\u201323). Effect of solar flares on ionospheric VLF radio wave propagation, modeling with GEANT4 and LWPC and determination of effective reflection height. Proceedings of the 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), Beijing, China.","DOI":"10.1109\/URSIGASS.2014.6929558"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"6799","DOI":"10.1002\/2015JA022233","article-title":"Study of the solar flares effect on VLF radio signal propagating along NRK-ALG path using LWPC code","volume":"121","author":"Bouderba","year":"2016","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_28","first-page":"377","article-title":"Solar flare effect on geomagnetic variation","volume":"11","author":"Ohshio","year":"1964","journal-title":"Rept. Ionos. Space Res. Jpn."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"67","DOI":"10.5636\/jgg.27.67","article-title":"Geomagnetic effects in the dark hemisphere associated with solar flares","volume":"27","author":"Sastri","year":"1975","journal-title":"J. Geomag. Geoelectr."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1871","DOI":"10.1016\/j.asr.2016.01.023","article-title":"Development of ground-based ELF\/VLF receiver system in Wuhan and its first results","volume":"57","author":"Chen","year":"2016","journal-title":"Adv. Space Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"166","DOI":"10.1007\/s11431-016-6103-5","article-title":"First observations of low latitude whistlers using WHU ELF\/VLF receiver system","volume":"60","author":"Chen","year":"2017","journal-title":"Sci. China Tech. Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"e2022JA030784","DOI":"10.1029\/2022JA030784","article-title":"First results of the wave measurements by the WHU VLF wave detection system at the Chinese Great Wall station in Antarctica","volume":"127","author":"Gu","year":"2022","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_33","first-page":"3223","article-title":"Modeling and analysis of NWC signal propagation amplitude based on LWPC and IRI models","volume":"62","author":"Yi","year":"2019","journal-title":"Chin. J. Geohpys."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"238","DOI":"10.26464\/epp2020023","article-title":"A detailed investigation of low latitude tweek atmospherics observed by the WHU ELF\/VLF receiver: 2. Occurrence features and associated ionospheric parameters","volume":"4","author":"Yi","year":"2020","journal-title":"Earth Planet Phys."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"120","DOI":"10.26464\/epp2020018","article-title":"A detailed investigation of low latitude tweek atmospherics observed by the WHU ELF\/VLF receiver: I. Automatic detection and analysis method","volume":"4","author":"Zhou","year":"2020","journal-title":"Earth Planet Phys."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"e2020JA029101","DOI":"10.1029\/2020JA029101","article-title":"Statistical analysis of very low frequency atmospheric noise caused by the global lightning using ground-based observations in China","volume":"126","author":"Gu","year":"2021","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1727","DOI":"10.1007\/s11431-021-2057-2","article-title":"Extraction of Alpha transmitter signals from single-station observations using the direction-finding method","volume":"65","author":"Gu","year":"2022","journal-title":"Sci. China Tech. Sci."},{"key":"ref_38","first-page":"145","article-title":"Sunrise effect of Very-Low-Frequency JJI transmitter signal propagation over an east-west path","volume":"65","author":"Wang","year":"2022","journal-title":"Chin. J. Geohpys."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2000207","DOI":"10.1109\/TGRS.2021.3056092","article-title":"Responses of the very low frequency transmitter signals during the solar eclipse on 26 December, 2019 over a North-South propagation path","volume":"60","author":"Gu","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_40","first-page":"4300","article-title":"Observations and analyses of the sunrise effect for NWC VLF transmitter signals","volume":"63","author":"Wang","year":"2020","journal-title":"Chin. J. Geohpys."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"570","DOI":"10.1029\/2012JA017916","article-title":"Response of the low ionosphere to X-ray and Lyman-\u03b1 solar flare emissions","volume":"118","author":"Raulin","year":"2013","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_42","unstructured":"Taylor, J.R. (1997). An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements, University Science Books."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1016\/0022-4073(89)90044-7","article-title":"The correlated-k method for radiation calculations in nonhomogeneous atmospheres","volume":"42","author":"Goody","year":"1989","journal-title":"J. Quant. Spectrosc. Radiat. Transfer."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1016\/j.solener.2014.12.028","article-title":"An integrated approach to estimate shortwave solar radiation on clear-sky days in rugged terrain using MODIS atmospheric products","volume":"113","author":"Zhang","year":"2015","journal-title":"Sol. Energy"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1051\/swsc\/2020027","article-title":"Geomagnetic solar flare effects: A review","volume":"10","author":"Curto","year":"2020","journal-title":"J. Space Weather Space Clim."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1186\/s40623-018-0794-8","article-title":"Solar fare effects on D-region ionosphere using VLF measurements during low- and high-solar activity phases of solar cycle 24","volume":"70","author":"Kumar","year":"2018","journal-title":"Earth Planets Space."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/4\/1018\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:32:34Z","timestamp":1760121154000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/4\/1018"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,2,12]]},"references-count":46,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["rs15041018"],"URL":"https:\/\/doi.org\/10.3390\/rs15041018","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,2,12]]}}}