Data · dataset · 2026
Variations of the nighttime thermospheric mass density at low and middle latitudes
Listed in National Center for Atmospheric Research
The latitudinal structure of the nighttime thermospheric mass density at 385 km has been investigated using observations made by the accelerometer onboard the CHAMP satellite between 2002 and 2007.
Description
The nighttime thermospheric mass density had a clear latitudinal variation. There was a local density peak around the geographic equator and two minima at about ± 30°.
This nighttime equatorial mass anomaly (NEMA) was opposite to the latitudinal variations of the daytime ionospheric equatorial anomaly and thermospheric mass density anomaly as both have minima at the magnetic dip equator and maxima around ± 20° in magnetic latitudes. This anomalous behavior of the nighttime thermospheric mass density had strong local time, seasonal, hemispheric, and solar cycle dependences. The largest crest-to-trough ratio between the peak density at the equator and the minima at the anomaly latitudes (± 30°) occurred between 0000 and 0200 local time.
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The NEMA appeared to be more pronounced during solstice seasons. It was also stronger during solar minimum than during solar maximum. In addition, under the same geophysical conditions, the empirical NRLMSISE-00 model shows similar but much weaker nighttime mass density anomaly features at low and middle latitudes.
A high-resolution National Center for Atmospheric Research-Thermosphere Ionosphere Mesosphere Energetics Global Circulation Model (TIMEGCM) simulation reproduced most of the observed latitudinal variations of the nighttime mass density as well as the thermospheric midnight temperature maximum (MTM). Model results suggest that superposition of diurnal and semidiurnal migrating tides of modes up to wave number 6 is the likely cause of both the NEMA and MTM phenomena.
Links
Get the data
- Publisher page n2t.org/ark:/85065/d7154hkh ↗
documentation · download · from data ucar edu
Where it is published
- data.ucar.edu /dataset/variations-of-the-nighttime-thermospheric-mass-density… ↗
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=0fc0c3e9-de37-47c1-8136-d1b6c12da… ↗
metadata API · from data ucar edu
Topics
- From keywords
- Earth & Environmental Science · Ocean & Atmospheric Science
- Inferred from text
- Atmospheric sciences 71% · Simulation 75%
Provenance · 1 source records, 9 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| National Center for Atmospheric Research | 0fc0c3e9-de37-47c1-8136-d1b6c12da292 | 12 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| concepts[field].anzsrc:group:3701 | enrichment · data ucar edu | taxonomy-embedding@1.1.0 | title+keywords+description (71%) |
| 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 | |
| concepts[method].local:method:simulation | enrichment · data ucar edu | keyword-concept-rules@1.0.0 | title+description (75%) |
| 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 |