On the derivation of an hourly local index to define the normal ionosphere
In this paper an hourly local ionospheric index f n F 2 is proposed to define the normal level of the undisturbed ionosphere. For the determination of this index a model is developed where the normal values of the f 0 F 2 parameter were reproduced using multiple regression analysis. For eac...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Istituto Nazionale di Geofisica e Vulcanologia (INGV)
2000-06-01
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| Series: | Annals of Geophysics |
| Subjects: | |
| Online Access: | http://www.annalsofgeophysics.eu/index.php/annals/article/view/3629 |
| _version_ | 1819177081871794176 |
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| author | I. Tsagouri G. Moraitis A. Belehaki |
| author_facet | I. Tsagouri G. Moraitis A. Belehaki |
| author_sort | I. Tsagouri |
| collection | DOAJ |
| description | In this paper an hourly local ionospheric index f n F 2 is proposed to define the normal level of the undisturbed ionosphere. For the determination of this index a model is developed where the normal values of the f 0 F 2 parameter were reproduced using multiple regression analysis. For each month of the year, for a given station, a set of 48 or 72 coefficients are calculated, depending on the monthly sunspot activity. Then, the normal values of the f 0 F 2 parameter are computed as a function of the daily sunspot number. The analysis of the model results revealed the following characteristics for the f n F 2 index: first, the temporal variations that characterize the normal ionosphere, imposing some artificial effects on the monthly median values, are eliminated from the newly derived f n F 2 index. Second, the f n F 2 index does not follow the false steplike variations observed in the monthly median f 0 F 2 time series, in transition periods from one month to another. Third, during intervals of low magnetospheric activity,the f n F 2 index presents a very good degree of fit with the observed f 0 F 2 parameter, compared to the monthly median f 0 F 2 behaviour. During disturbed conditions, the f n F 2 index remains at the normal level, whereas median values are affected by ionospheric disturbances. In general, the data analysis showed that the f n F 2 index varies only with the daily sunspot number Rz and is independent of the magnetospheric activity, approaching the level of the normal ionosphere with a high degree of confidence. |
| first_indexed | 2024-12-22T21:20:59Z |
| format | Article |
| id | doaj.art-14578a96a8a44278b4159333454407f4 |
| institution | Directory Open Access Journal |
| issn | 1593-5213 2037-416X |
| language | English |
| last_indexed | 2024-12-22T21:20:59Z |
| publishDate | 2000-06-01 |
| publisher | Istituto Nazionale di Geofisica e Vulcanologia (INGV) |
| record_format | Article |
| series | Annals of Geophysics |
| spelling | doaj.art-14578a96a8a44278b4159333454407f42022-12-21T18:12:12ZengIstituto Nazionale di Geofisica e Vulcanologia (INGV)Annals of Geophysics1593-52132037-416X2000-06-0143110.4401/ag-3629On the derivation of an hourly local index to define the normal ionosphereI. TsagouriG. MoraitisA. BelehakiIn this paper an hourly local ionospheric index f n F 2 is proposed to define the normal level of the undisturbed ionosphere. For the determination of this index a model is developed where the normal values of the f 0 F 2 parameter were reproduced using multiple regression analysis. For each month of the year, for a given station, a set of 48 or 72 coefficients are calculated, depending on the monthly sunspot activity. Then, the normal values of the f 0 F 2 parameter are computed as a function of the daily sunspot number. The analysis of the model results revealed the following characteristics for the f n F 2 index: first, the temporal variations that characterize the normal ionosphere, imposing some artificial effects on the monthly median values, are eliminated from the newly derived f n F 2 index. Second, the f n F 2 index does not follow the false steplike variations observed in the monthly median f 0 F 2 time series, in transition periods from one month to another. Third, during intervals of low magnetospheric activity,the f n F 2 index presents a very good degree of fit with the observed f 0 F 2 parameter, compared to the monthly median f 0 F 2 behaviour. During disturbed conditions, the f n F 2 index remains at the normal level, whereas median values are affected by ionospheric disturbances. In general, the data analysis showed that the f n F 2 index varies only with the daily sunspot number Rz and is independent of the magnetospheric activity, approaching the level of the normal ionosphere with a high degree of confidence.http://www.annalsofgeophysics.eu/index.php/annals/article/view/3629reference ionosphereionospheric disturbanceionospheric indices |
| spellingShingle | I. Tsagouri G. Moraitis A. Belehaki On the derivation of an hourly local index to define the normal ionosphere Annals of Geophysics reference ionosphere ionospheric disturbance ionospheric indices |
| title | On the derivation of an hourly local index to define the normal ionosphere |
| title_full | On the derivation of an hourly local index to define the normal ionosphere |
| title_fullStr | On the derivation of an hourly local index to define the normal ionosphere |
| title_full_unstemmed | On the derivation of an hourly local index to define the normal ionosphere |
| title_short | On the derivation of an hourly local index to define the normal ionosphere |
| title_sort | on the derivation of an hourly local index to define the normal ionosphere |
| topic | reference ionosphere ionospheric disturbance ionospheric indices |
| url | http://www.annalsofgeophysics.eu/index.php/annals/article/view/3629 |
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