Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends?
<p>The International Reference Ionosphere (IRI) is a widely used empirical ionospheric model based on observations from a worldwide network of ionospheric stations. Therefore, it would be reasonable to expect it to capture long-term changes in key ionospheric parameters, such as <i>fo<...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/13973/2023/acp-23-13973-2023.pdf |
| _version_ | 1797633131016093696 |
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| author | B. S. Zossi B. S. Zossi T. Duran T. Duran F. D. Medina F. D. Medina B. F. de Haro Barbas B. F. de Haro Barbas Y. Melendi Y. Melendi A. G. Elias A. G. Elias |
| author_facet | B. S. Zossi B. S. Zossi T. Duran T. Duran F. D. Medina F. D. Medina B. F. de Haro Barbas B. F. de Haro Barbas Y. Melendi Y. Melendi A. G. Elias A. G. Elias |
| author_sort | B. S. Zossi |
| collection | DOAJ |
| description | <p>The International Reference Ionosphere (IRI) is a widely used empirical ionospheric model based on observations from a worldwide network of ionospheric stations. Therefore, it would be reasonable to expect it to capture long-term changes in key ionospheric parameters, such as <i>fo</i>F2 and <i>hm</i>F2 linked to trend forcings like greenhouse gas increasing concentrations and the Earth's magnetic field secular variation. Despite the numerous reported trends in <i>fo</i>F2 and <i>hm</i>F2 derived from experimental data and model results, there are inconsistencies that require continuous refinement of trend estimation methods and regular data updates. This ongoing effort is crucial to address the difficulties posed by the weak signal-to-noise ratio characteristic of ionospheric long-term trends. Furthermore, the experimental verification of these trends remains challenging, primarily due to time and spatial coverage limitations of measured data series. Achieving these needs for accurate detection of long-term trends requires extensive global coverage and high resolution of ionospheric measurements together with long enough periods spanning multiple solar cycles to properly filter out variations of shorter terms than the sought trend. Considering these challenges, IRI-modeled <i>fo</i>F2 and <i>hm</i>F2 parameters offer a valuable alternative for assessing trends and obtaining a first approximation of a plausible global picture representative of experimental trends. This work presents these global trend patterns, considering the period 1960–2022 using the IRI-Plas 2020 version, which are consistent with other model predictions. While IRI explicitly takes into account the Earth's magnetic field variations, the increase in the concentrations of greenhouse gases appears indirectly through the Ionospheric Global index (IG) which is derived from ionospheric measurements. F2-region trends induced by the first mechanism should be important only around the magnetic equator at the longitudinal range with the strongest displacement, and it should be negligible out of this region. Conversely, trends induced by the greenhouse effect, which are the controversial ones, should be dominant away from the geomagnetic equator and should globally average to negative values in both cases, i.e., <i>fo</i>F2 and <i>hm</i>F2. Effectively, these negative global means are verified by trends based on IRI-Plas, even though not for the correct reasons in the <i>hm</i>F2 case. In addition, a verification was performed for more localized <i>fo</i>F2 trend values, considering data from nine mid-latitude stations, and a reasonable level of agreement was observed. It is concluded that the IRI model can be a valuable tool for obtaining preliminary approximations of the Earth's magnetic-field-induced long-term changes in <i>fo</i>F2 and <i>hm</i>F2, as well as of experimental trends only in the <i>fo</i>F2 case. The latter does not hold for <i>hm</i>F2, even if the trends obtained are close to the expected values.</p> |
| first_indexed | 2024-03-11T11:49:42Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-03-11T11:49:42Z |
| publishDate | 2023-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-4ae7e062f93b4467ae31d57b8946f1ab2023-11-09T10:20:35ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-11-0123139731398610.5194/acp-23-13973-2023Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends?B. S. Zossi0B. S. Zossi1T. Duran2T. Duran3F. D. Medina4F. D. Medina5B. F. de Haro Barbas6B. F. de Haro Barbas7Y. Melendi8Y. Melendi9A. G. Elias10A. G. Elias11INFINOA, CONICET-UNT, Tucumán, 4000, ArgentinaLaboratorio de Ionosfera, Atmosfera Neutra y Magnetosfera (LIANM), Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Tucumán, 4000, ArgentinaDepartamento de Física, Universidad Nacional del Sur (UNS), Bahía Blanca, 8000, ArgentinaInstituto de Física del Sur (CONICET-UNS), Bahía Blanca, 8000, ArgentinaINFINOA, CONICET-UNT, Tucumán, 4000, ArgentinaLaboratorio de Ionosfera, Atmosfera Neutra y Magnetosfera (LIANM), Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Tucumán, 4000, ArgentinaINFINOA, CONICET-UNT, Tucumán, 4000, ArgentinaLaboratorio de Ionosfera, Atmosfera Neutra y Magnetosfera (LIANM), Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Tucumán, 4000, ArgentinaDepartamento de Física, Universidad Nacional del Sur (UNS), Bahía Blanca, 8000, ArgentinaInstituto de Física del Sur (CONICET-UNS), Bahía Blanca, 8000, ArgentinaINFINOA, CONICET-UNT, Tucumán, 4000, ArgentinaLaboratorio de Ionosfera, Atmosfera Neutra y Magnetosfera (LIANM), Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Tucumán, 4000, Argentina<p>The International Reference Ionosphere (IRI) is a widely used empirical ionospheric model based on observations from a worldwide network of ionospheric stations. Therefore, it would be reasonable to expect it to capture long-term changes in key ionospheric parameters, such as <i>fo</i>F2 and <i>hm</i>F2 linked to trend forcings like greenhouse gas increasing concentrations and the Earth's magnetic field secular variation. Despite the numerous reported trends in <i>fo</i>F2 and <i>hm</i>F2 derived from experimental data and model results, there are inconsistencies that require continuous refinement of trend estimation methods and regular data updates. This ongoing effort is crucial to address the difficulties posed by the weak signal-to-noise ratio characteristic of ionospheric long-term trends. Furthermore, the experimental verification of these trends remains challenging, primarily due to time and spatial coverage limitations of measured data series. Achieving these needs for accurate detection of long-term trends requires extensive global coverage and high resolution of ionospheric measurements together with long enough periods spanning multiple solar cycles to properly filter out variations of shorter terms than the sought trend. Considering these challenges, IRI-modeled <i>fo</i>F2 and <i>hm</i>F2 parameters offer a valuable alternative for assessing trends and obtaining a first approximation of a plausible global picture representative of experimental trends. This work presents these global trend patterns, considering the period 1960–2022 using the IRI-Plas 2020 version, which are consistent with other model predictions. While IRI explicitly takes into account the Earth's magnetic field variations, the increase in the concentrations of greenhouse gases appears indirectly through the Ionospheric Global index (IG) which is derived from ionospheric measurements. F2-region trends induced by the first mechanism should be important only around the magnetic equator at the longitudinal range with the strongest displacement, and it should be negligible out of this region. Conversely, trends induced by the greenhouse effect, which are the controversial ones, should be dominant away from the geomagnetic equator and should globally average to negative values in both cases, i.e., <i>fo</i>F2 and <i>hm</i>F2. Effectively, these negative global means are verified by trends based on IRI-Plas, even though not for the correct reasons in the <i>hm</i>F2 case. In addition, a verification was performed for more localized <i>fo</i>F2 trend values, considering data from nine mid-latitude stations, and a reasonable level of agreement was observed. It is concluded that the IRI model can be a valuable tool for obtaining preliminary approximations of the Earth's magnetic-field-induced long-term changes in <i>fo</i>F2 and <i>hm</i>F2, as well as of experimental trends only in the <i>fo</i>F2 case. The latter does not hold for <i>hm</i>F2, even if the trends obtained are close to the expected values.</p>https://acp.copernicus.org/articles/23/13973/2023/acp-23-13973-2023.pdf |
| spellingShingle | B. S. Zossi B. S. Zossi T. Duran T. Duran F. D. Medina F. D. Medina B. F. de Haro Barbas B. F. de Haro Barbas Y. Melendi Y. Melendi A. G. Elias A. G. Elias Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends? Atmospheric Chemistry and Physics |
| title | Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends? |
| title_full | Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends? |
| title_fullStr | Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends? |
| title_full_unstemmed | Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends? |
| title_short | Evaluating F2-region long-term trends using the International Reference Ionosphere (IRI) model: is this a feasible approximation for experimental trends? |
| title_sort | evaluating f2 region long term trends using the international reference ionosphere iri model is this a feasible approximation for experimental trends |
| url | https://acp.copernicus.org/articles/23/13973/2023/acp-23-13973-2023.pdf |
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