Data · dataset · 2026
Changes in the Earth's magnetic field over the past century: Effects on the ionosphere-thermosphere system and solar quiet (Sq) magnetic variation
Listed in National Center for Atmospheric Research
We investigated the contribution of changes in the Earth's magnetic field to long-term trends in the ionosphere, thermosphere, and solar quiet (Sq) magnetic variation using the Coupled Magnetosphere-Ionosphere-Thermosphere (CMIT) model.
Description
Simulations with the magnetic fields of 1908, 1958, and 2008 were done. The strongest differences occurred between ~40°S-40°N and ~100°W-50°E, which we refer to as the Atlantic region.
The height and critical frequency of the F2 layer peak, hmF2 and foF2, changed due to changes in the vertical EÃB drift and the vertical components of diffusion and transport by neutral winds along the magnetic field. Changes in electron density resulted in changes in electron temperature of the opposite sign, which in turn produced small corresponding changes in ion temperature. Changes in neutral temperature were not statistically significant.
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Strong changes in the daily amplitude of the Sq variation occurred at low magnetic latitudes due to the northward movement of the magnetic equator and the westward drift of the magnetic field. The simulated changes in hmF2, foF2, and Sq amplitude translate into typical trends of ±1km/decade (night) to ±3km/decade (day), -0.1 to +0.05MHz/decade, and ±5 to ±10nT/century, respectively. These are mostly comparable in magnitude to observed trends in the Atlantic region.
The simulated Atlantic region trends in hmF2 and foF2 are ~2.5 times larger than the estimated effect of enhanced greenhouse gases on hmF2 and foF2. The secular variation of the Earth's magnetic field may therefore be the dominant cause of trends in the Atlantic region ionosphere.
Links
Get the data
- Publisher page n2t.org/ark:/85065/d7j9677h ↗
documentation · download · from data ucar edu
Where it is published
- data.ucar.edu /dataset/changes-in-the-earths-magnetic-field-over-the-past-cen… ↗
National Center for Atmospheric Research dataset page
landing page · from data ucar edu
Catalogue records · 1
- CKAN API data.ucar.edu/api/3/action/package_show?id=050acc8e-4d9a-42b9-892a-f5124f8cd… ↗
metadata API · from data ucar edu
Topics
- From keywords
- Earth & Environmental Science · Ocean & Atmospheric Science
- Inferred from text
- Geophysics 72%
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| National Center for Atmospheric Research | 050acc8e-4d9a-42b9-892a-f5124f8cdbd4 | 12 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| concepts[field].anzsrc:group:3706 | enrichment · data ucar edu | taxonomy-embedding@1.1.0 | title+keywords+description (72%) |
| concepts[field].local:field:earth-environmental | mapping · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| concepts[field].local:field:ocean-atmospheric | mapping · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| created_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| description | source · data ucar edu | connector:data_ucar_edu@1.0.0 | /notes |
| publication_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| title | source · data ucar edu | connector:data_ucar_edu@1.0.0 | /title |
| updated_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 |