Solar Variability in the Mg ii h and k Lines
Solar irradiance and its variations in the ultraviolet (UV) control the photochemistry in Earth's atmosphere and influence Earth's climate. The variability in the Mg ii h and k core-to-wing ratio, also known as the Mg ii index, is highly correlated with the solar UV irradiance variability....
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ada6af |
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| author | K. Sowmya M. Snow A. I. Shapiro N. A. Krivova T. Chatzistergos S. K. Solanki |
| author_facet | K. Sowmya M. Snow A. I. Shapiro N. A. Krivova T. Chatzistergos S. K. Solanki |
| author_sort | K. Sowmya |
| collection | DOAJ |
| description | Solar irradiance and its variations in the ultraviolet (UV) control the photochemistry in Earth's atmosphere and influence Earth's climate. The variability in the Mg ii h and k core-to-wing ratio, also known as the Mg ii index, is highly correlated with the solar UV irradiance variability. Because of this, the Mg ii index is routinely used as a proxy for solar UV irradiance variability, which can help to get insights into the influence of solar UV irradiance variability on Earth's climate. Measurements of the Mg ii index, however, have only been carried out since 1978 and do not cover climate-relevant timescales longer than a few decades. Here we present a model to calculate the Mg ii index and its variability based on the well-established Spectral And Total Irradiance REconstruction (SATIRE) model. We demonstrate that our model calculations yield an excellent agreement with the observed Mg ii index variations, both on the solar activity cycle and on the solar rotation timescales. Using this model, we synthesize the Mg ii index time series on climate-relevant timescales of decades and longer. Here we present the time series of the Mg ii index spanning nearly three centuries. |
| first_indexed | 2025-03-17T01:09:10Z |
| format | Article |
| id | doaj.art-6ad67233ad6a4cf4ad3ec0f22653d831 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2025-03-17T01:09:10Z |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-6ad67233ad6a4cf4ad3ec0f22653d8312025-02-18T20:20:40ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01980217310.3847/1538-4357/ada6afSolar Variability in the Mg ii h and k LinesK. Sowmya0https://orcid.org/0000-0002-3243-1230M. Snow1https://orcid.org/0000-0001-9106-1332A. I. Shapiro2https://orcid.org/0000-0002-8842-5403N. A. Krivova3https://orcid.org/0000-0002-1377-3067T. Chatzistergos4https://orcid.org/0000-0002-0335-9831S. K. Solanki5https://orcid.org/0000-0002-3418-8449Max-Planck-Institut für Sonnensystemforschung , Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany ; krishnamurthy@mps.mpg.de; Institute of Physics, University of Graz , Universitätsplatz 5, 8010 Graz, AustriaLaboratory for Atmospheric and Space Physics, University of Colorado Boulder , 1234 Innovation Dr., Boulder, CO 80303, USA; South African National Space Agency , Hospital Street, Hermanus 7200, South Africa; Department of Physics and Astronomy, University of the Western Cape , Robert Sobukwe Road, Bellville 7535, South AfricaMax-Planck-Institut für Sonnensystemforschung , Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany ; krishnamurthy@mps.mpg.de; Institute of Physics, University of Graz , Universitätsplatz 5, 8010 Graz, AustriaMax-Planck-Institut für Sonnensystemforschung , Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany ; krishnamurthy@mps.mpg.deMax-Planck-Institut für Sonnensystemforschung , Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany ; krishnamurthy@mps.mpg.deMax-Planck-Institut für Sonnensystemforschung , Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany ; krishnamurthy@mps.mpg.deSolar irradiance and its variations in the ultraviolet (UV) control the photochemistry in Earth's atmosphere and influence Earth's climate. The variability in the Mg ii h and k core-to-wing ratio, also known as the Mg ii index, is highly correlated with the solar UV irradiance variability. Because of this, the Mg ii index is routinely used as a proxy for solar UV irradiance variability, which can help to get insights into the influence of solar UV irradiance variability on Earth's climate. Measurements of the Mg ii index, however, have only been carried out since 1978 and do not cover climate-relevant timescales longer than a few decades. Here we present a model to calculate the Mg ii index and its variability based on the well-established Spectral And Total Irradiance REconstruction (SATIRE) model. We demonstrate that our model calculations yield an excellent agreement with the observed Mg ii index variations, both on the solar activity cycle and on the solar rotation timescales. Using this model, we synthesize the Mg ii index time series on climate-relevant timescales of decades and longer. Here we present the time series of the Mg ii index spanning nearly three centuries.https://doi.org/10.3847/1538-4357/ada6afSolar activitySolar ultraviolet emissionSolar chromospherePlagesSolar transition region |
| spellingShingle | K. Sowmya M. Snow A. I. Shapiro N. A. Krivova T. Chatzistergos S. K. Solanki Solar Variability in the Mg ii h and k Lines The Astrophysical Journal Solar activity Solar ultraviolet emission Solar chromosphere Plages Solar transition region |
| title | Solar Variability in the Mg ii h and k Lines |
| title_full | Solar Variability in the Mg ii h and k Lines |
| title_fullStr | Solar Variability in the Mg ii h and k Lines |
| title_full_unstemmed | Solar Variability in the Mg ii h and k Lines |
| title_short | Solar Variability in the Mg ii h and k Lines |
| title_sort | solar variability in the mg ii h and k lines |
| topic | Solar activity Solar ultraviolet emission Solar chromosphere Plages Solar transition region |
| url | https://doi.org/10.3847/1538-4357/ada6af |
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