Ring current influence on auroral electrojet predictions
Geomagnetic storms and substorms develop under strong control of the solar wind. This is demonstrated by the fact that the geomagnetic activity indices <i>Dst</i> and <i>AE</i> can be predicted from the solar wind alone. A consequence of the strong control by a common sour...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
1999-10-01
|
| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/17/1268/1999/angeo-17-1268-1999.pdf |
| _version_ | 1818856429059047424 |
|---|---|
| author | H. Gleisner H. Lundstedt |
| author_facet | H. Gleisner H. Lundstedt |
| author_sort | H. Gleisner |
| collection | DOAJ |
| description | Geomagnetic storms and substorms develop
under strong control of the solar wind. This is demonstrated by the fact that
the geomagnetic activity indices <i>Dst</i> and <i>AE</i> can be predicted from
the solar wind alone. A consequence of the strong control by a common source is
that substorm and storm indices tend to be highly correlated. However, a part of
this correlation is likely to be an effect of internal magnetospheric processes,
such as a ring-current modulation of the solar wind-<i>AE</i> relation.
<p style="line-height: 20px;">The present work extends previous studies of nonlinear <i>AE</i>
predictions from the solar wind. It is examined whether the <i>AE</i>
predictions are modulated by the <i>Dst</i> index.This is accomplished by
comparing neural network predictions from <i>Dst</i> and the solar wind, with
predictions from the solar wind alone. Two conclusions are reached: (1) with an
optimal set of solar-wind data available, the <i>AE</i> predictions are not
markedly improved by the <i>Dst</i> input, but (2) the <i>AE</i> predictions are
improved by <i>Dst</i> if less than, or other than, the optimum solar-wind data
are available to the net. It appears that the solar wind-<i>AE</i> relation
described by an optimized neural net is not significantly modified by the
magnetosphere's <i>Dst</i> state. When the solar wind alone is used to predict <i>AE</i>,
the correlation between predicted and observed <i>AE</i> is 0.86, while the
prediction residual is nearly uncorrelated to <i>Dst</i>. Further, the finding
that <i>Dst</i> can partly compensate for missing information on the solar wind,
is of potential importance in operational forecasting where gaps in the stream
of real time solar-wind data are a common occurrence.<br><br><b>Key words. </b>Magnetospheric physics (solar wind ·
magnetosphere interactions; storms and substorms) |
| first_indexed | 2024-12-19T08:24:21Z |
| format | Article |
| id | doaj.art-c9344bfc648d4ba48765e8c19f611cac |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-19T08:24:21Z |
| publishDate | 1999-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-c9344bfc648d4ba48765e8c19f611cac2022-12-21T20:29:20ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05761999-10-01171268127510.1007/s00585-999-1268-xRing current influence on auroral electrojet predictionsH. Gleisner0H. Lundstedt1Lund Observatory, Box 43, S-22100 Lund, SwedenLund Observatory, Box 43, S-22100 Lund, SwedenGeomagnetic storms and substorms develop under strong control of the solar wind. This is demonstrated by the fact that the geomagnetic activity indices <i>Dst</i> and <i>AE</i> can be predicted from the solar wind alone. A consequence of the strong control by a common source is that substorm and storm indices tend to be highly correlated. However, a part of this correlation is likely to be an effect of internal magnetospheric processes, such as a ring-current modulation of the solar wind-<i>AE</i> relation. <p style="line-height: 20px;">The present work extends previous studies of nonlinear <i>AE</i> predictions from the solar wind. It is examined whether the <i>AE</i> predictions are modulated by the <i>Dst</i> index.This is accomplished by comparing neural network predictions from <i>Dst</i> and the solar wind, with predictions from the solar wind alone. Two conclusions are reached: (1) with an optimal set of solar-wind data available, the <i>AE</i> predictions are not markedly improved by the <i>Dst</i> input, but (2) the <i>AE</i> predictions are improved by <i>Dst</i> if less than, or other than, the optimum solar-wind data are available to the net. It appears that the solar wind-<i>AE</i> relation described by an optimized neural net is not significantly modified by the magnetosphere's <i>Dst</i> state. When the solar wind alone is used to predict <i>AE</i>, the correlation between predicted and observed <i>AE</i> is 0.86, while the prediction residual is nearly uncorrelated to <i>Dst</i>. Further, the finding that <i>Dst</i> can partly compensate for missing information on the solar wind, is of potential importance in operational forecasting where gaps in the stream of real time solar-wind data are a common occurrence.<br><br><b>Key words. </b>Magnetospheric physics (solar wind · magnetosphere interactions; storms and substorms)https://www.ann-geophys.net/17/1268/1999/angeo-17-1268-1999.pdf |
| spellingShingle | H. Gleisner H. Lundstedt Ring current influence on auroral electrojet predictions Annales Geophysicae |
| title | Ring current influence on auroral electrojet predictions |
| title_full | Ring current influence on auroral electrojet predictions |
| title_fullStr | Ring current influence on auroral electrojet predictions |
| title_full_unstemmed | Ring current influence on auroral electrojet predictions |
| title_short | Ring current influence on auroral electrojet predictions |
| title_sort | ring current influence on auroral electrojet predictions |
| url | https://www.ann-geophys.net/17/1268/1999/angeo-17-1268-1999.pdf |
| work_keys_str_mv | AT hgleisner ringcurrentinfluenceonauroralelectrojetpredictions AT hlundstedt ringcurrentinfluenceonauroralelectrojetpredictions |