Results 61 to 70 of about 11,749 (226)

Seasonal and Altitude Dependence of Thermospheric Metastable Helium Densities Measured by Fluorescence Lidar

Geophysical Research Letters
Airglow originating from metastable helium He(23S) at 1,083 nm has been used to study the upper thermosphere since its discovery in 1959, yielding insights into, for example, solar EUV intensities and thermospheric photoelectron densities.
C. Geach, B. Kaifler
doaj   +1 more source

Reduced Order Probabilistic Emulation for Physics‐Based Thermosphere Models

Space Weather, 2023
The geospace environment is volatile and highly driven. Space weather has effects on Earth's magnetosphere that cause a dynamic and enigmatic response in the thermosphere, particularly on the evolution of neutral mass density.
Richard J. Licata, Piyush M. Mehta
doaj   +1 more source

Seasonal and Diurnal Variability of Thermospheric Metastable Helium Observed by Multi‐Platform Observations and Numerical Modeling

Geophysical Research Letters, Volume 53, Issue 20, 28 October 2026.
Abstract Metastable helium (He∗ ${\text{He}}^{\ast }$) in the thermosphere emits at 1,083 nm and provides a powerful diagnostic of thermospheric composition, solar radiation, and transport. Its detection remains challenging because of its extremely low density and high‐altitude.
Zhenwei Liu, Chuan Huang, Jinru Cheng, Tangsheng Cheng, Hang Zhou, Chaomei Wu, Chen Liang, Tingdi Chen, Weilong Luo, Chong Wang, Zhaofeng Wang, Ruocan Zhao, Xianghui Xue   +12 more
wiley   +1 more source

What to Do When the F10.7 Goes Out?

Space Weather, 2023
The solar radio flux at 10.7 cm, known as F10.7, is a critical operational space weather index. However, without a clear backup, any interruption to the service can result in substantial errors in model outputs.
Sean Elvidge, David R. Themens, Matthew K. Brown, Elizabeth Donegan‐Lawley   +3 more
doaj   +1 more source

Quasi‐Homologous Solar Flares and Impacts on Thermospheric Density and Satellite Orbital Drag

Geophysical Research Letters, Volume 53, Issue 20, 28 October 2026.
Abstract Quasi‐Homologous Flaring (QHF) activity from active regions on the Sun releases intense electromagnetic radiation in recurrent bursts over extended periods. In this letter, we present the effects of recurrent impulsive extreme ultraviolet (EUV) heating on thermospheric neutral density and the resulting atmospheric drag on satellites based on ...
S. Tulasi Ram, Princy K. Dubey, S. Mondal, Denny M. Oliveira, Jayashree Bulusu, Chinmaya Nayak, D. Rout, Anil Raghav, A. P. Dimri   +8 more
wiley   +1 more source

Chemistry of the thermosphere and ionosphere [PDF]

Journal of Atmospheric and Terrestrial Physics, 1979
The ionosphere offers an excellent laboratory for the study of atomic and molecular processes. Densities are low, permitting highly reactive species to accumulate in measurable quantities. Temporal and spatial scales are large, and the solar energy source causes substantial departures from thermodynamic equilibrium.
Torr, D. G., Torr, Marsha R.
openaire   +2 more sources

Atmospheric and Ionospheric Responses to Hunga‐Tonga Volcano Eruption Simulated by WACCM‐X

Geophysical Research Letters, 2023
High‐resolution Whole Atmosphere Community Climate Model with thermosphere/ionosphere extension is used to simulate the responses to the Hunga‐Tonga volcano eruption on 15 January 2022.
H.‐L. Liu, W. Wang, J. D. Huba, P. H. Lauritzen, F. Vitt   +4 more
doaj   +1 more source

The Long‐Term Trend of the Equatorial Electrojet Over Indian Sector

Geophysical Research Letters, Volume 53, Issue 20, 28 October 2026.
Abstract The upper‐atmosphere cooling trend is well documented, while the long‐term trend of the ionospheric electrodynamics remains poorly understood. Using two geomagnetic observation data sets over Indian sector, we analyze the long‐term trend of the monthly‐median equatorial electrojet (EEJ) in 1967–2015 after removing the solar activity and ...
Ruilong Zhang, Xu Zhou, Yuzhou Wang, Libo Liu, Yiding Chen, Huijun Le   +5 more
wiley   +1 more source

Observations of thermosphere and ionosphere changes due to the dissipative 6.5-day wave in the lower thermosphere [PDF]

, 2015
In the current work, temperature and wind data from the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite during the years 2002–2007 were used to describe the seasonal variations of the westward propagating 6.5-day ...
L. C. Chang, Q. Gan, J. Yue, W. B. Wang, J. Du, S. D. Zhang   +5 more
core   +1 more source

Improved Thermosphere Mass Density Recovery During the 5 April 2010 Geomagnetic Storm by Assimilating NO Cooling Rates in a Coupled Thermosphere-Ionosphere Model

, 2023
International audienceThe recovery of thermosphere mass density following geomagnetic storms is a result of competing heating and cooling processes. Simulations often underestimate the speed of the recovery.
Pedatella, Nicholas M., Yue, Xinan, Yu, Tingting, Astafyeva, Elvira, He, Jianhui, Ren, Zhipeng   +5 more
core   +1 more source