Results 51 to 60 of about 6,139 (217)

Thermospheric density structures over the polar regions observed with CHAMP [PDF]

Annales Geophysicae, 2005
Abstract. We report on the unexpected detection of considerable structure in high latitude thermospheric densities, as derived from an accelerometer onboard the CHAMP satellite. The width of the structures, which can either be maxima or minima, varies between a few hundred km and 2000 km. The amplitudes of these density extrema can reach 50% of ambient.
Schlegel, K., Lühr, H., St.-Maurice, J., Crowley, G., Hackert, C.   +4 more
openaire   +7 more sources

Multi‐Decadal Trends in the Low Latitude foF2 Driven by Secular Magnetic Variations

Journal of Geophysical Research: Space Physics, Volume 131, Issue 5, May 2026.
Abstract Long‐term ionospheric trends have been widely studied, but their origin and magnitude remain subjects of debate. This study quantifies the linear trend in the F2‐region critical frequency (foF2) and its local time dependence using observations from eight low‐latitude ionosonde stations.
D. Singh, S. R. Zhang, L. P. Goncharenko, I. S. Batista, A. J. Coster   +4 more
wiley   +1 more source

First Quantitative Results on the Response of Green and Red Line Dayglow Emissions to Solar Flares of Different Magnitudes

Geophysical Research Letters, Volume 53, Issue 8, 28 April 2026.
Abstract Flares originate from the impulsive release of magnetic energy in the solar atmosphere. The rise in X‐ray flux enhances ionization/electron content in the upper atmosphere, modifying the photochemical and dynamical processes that govern the ionosphere‐thermosphere behavior.
Komal, Duggirala Pallamraju
wiley   +1 more source

Improving Thermospheric Density Predictions in Low‐Earth Orbit With Machine Learning

Space Weather
Thermospheric density is one of the main sources of uncertainty in the estimation of satellites' position and velocity in low‐Earth orbit. This has negative consequences in several space domains, including space traffic management, collision avoidance ...
Giacomo Acciarini, Edward Brown, Tom Berger, Madhulika Guhathakurta, James Parr, Christopher Bridges, Atılım Güneş Baydin   +6 more
doaj   +1 more source

Can the International Reference Ionosphere Model Predict Long‐Term Trends in the Ionosphere?

Geophysical Research Letters, Volume 53, Issue 8, 28 April 2026.
Abstract The International Reference Ionosphere (IRI) model can partially reproduce ionospheric long‐term trends (LTTs), although not intentionally, provided that an appropriate effective ionospheric index is used. We evaluate how model predictions driven by a solar activity proxy (R12) and by an effective ionospheric proxy (IG12) can reproduce the ...
A. Pignalberi, M. Pietrella, T. Alberti, M. Pezzopane   +3 more
wiley   +1 more source

Do Eclipse‐Induced Thermospheric TADs Originate From Above or Below?

Geophysical Research Letters, Volume 53, Issue 7, 16 April 2026.
Abstract Solar eclipses generate significant wave activity in the Earth's upper atmosphere. The source region of eclipse‐induced Traveling Atmospheric Disturbances (TADs) in the upper thermosphere—particularly the relative contributions of gravity waves from the thermosphere itself versus the lower atmosphere—remains unknown. Using the Whole Atmosphere
Yu Jiao, Jing Liu, Shuhan Li, Joseph M. McInerney, Jianyong Li, Yuyan Yang   +5 more
wiley   +1 more source

Climatology of the equatorial thermospheric mass density anomaly [PDF]

Journal of Geophysical Research: Space Physics, 2007
The equatorial anomaly is an interesting and important feature of the Earth's thermosphere‐ionosphere coupling in tropical regions. It is an anomalous latitudinal distribution found in both the ionized and unionized part of the atmosphere. Its equinox configuration consists of a minimum near the dip equator flanked by two maxima on both sides.
Liu, Huixin, Lühr, Hermann, Watanabe, Shigeto   +2 more
openaire   +4 more sources

Sudden Ionospheric Disturbances Generated by Solar Flares—Not so Sudden?

Geophysical Research Letters, Volume 53, Issue 7, 16 April 2026.
Abstract It is known that solar flares generate instantaneous ionization enhancement, referred to as sudden ionospheric disturbance (SID), that occurs simultaneously across the entire dayside. In this work, we use high‐rate 1‐s data of total electron content (TEC) to analyse ionospheric response to 13 solar flares that occurred in 2003–2023.
B. Maletckii, E. Astafyeva, N. M. Pedatella, L. Qian   +3 more
wiley   +1 more source

The Short‐Time Prediction of Thermospheric Mass Density Based on Ensemble‐Transfer Learning

Space Weather, 2023
Reliable short‐time prediction of thermospheric mass density along the satellite orbit is always essential but challenging for the operation of Low‐Earth orbit satellites.
Peian Wang, Zhou Chen, Xiaohua Deng, Jing‐Song Wang, Rongxing Tang, Haimeng Li, Sheng Hong, Zhiping Wu   +7 more
doaj   +1 more source

On the contribution of thermal excitation to the total 630.0 nm emissions in the northern cusp ionosphere [PDF]

, 2017
Direct impact excitation by precipitating electrons is believed to be the main source of 630.0 nm emissions in the cusp ionosphere. However, this paper investigates a different source, 630.0 emissions caused by thermally excited atomic oxygen O$(^{1}$D ...
Johnsen, Magnar G., Kwagala, Norah Kaggwa, Lorentzen, Dag A., Oksavik, Kjellmar   +3 more
core   +3 more sources