Results 11 to 20 of about 87,822 (293)

Seasonal variations of equatorial spread-F [PDF]

Annales Geophysicae, 1994
The occurrence of spread-F at Trivandrum (8.5°N, 77°E, dip 0.5°N) has been investigated on a seasonal basis in sunspot maximum and minimum years in terms of the growth rate of irregularities by the generalized collisional Rayleigh-Taylor (GRT ...
K. S. V. Subbarao, B. V. Krishna Murthy
doaj   +1 more source

Topside equatorial spread F-related field-aligned Poynting flux: observations and simulations

Earth, Planets and Space, 2022
Electric and magnetic field data from the Swarm constellation mission are used to report on the Poynting flux associated with postsunset topside equatorial spread F.
J. Rodríguez-Zuluaga, C. Stolle, D. Hysell, D. J. Knudsen   +3 more
doaj   +1 more source

Modeling Post-Sunset Equatorial Spread-F Occurrence as a Function of Evening Upward Plasma Drift Using Logistic Regression, Deduced from Ionosondes in Southeast Asia

Remote Sensing, 2022
The occurrence of post-sunset equatorial spread-F (ESF) could have detrimental effects on trans-ionospheric radio wave propagation used in modern communications systems.
Prayitno Abadi, Umar Ali Ahmad, Yuichi Otsuka, Punyawi Jamjareegulgarn, Dyah Rahayu Martiningrum, Agri Faturahman, Septi Perwitasari, Randy Erfa Saputra, Reza Rendian Septiawan   +8 more
doaj   +1 more source

HF radar observations of equatorial spread-F over West Africa [PDF]

Annales Geophysicae, 1996
New experimental data depicting equatorial spread-F were taken during an HF radar sounding campaign in Korhogo (Ivory Coast, 9°24N, 5°37W, dip 4°S). Range-time-intensity maps of the radar echoes have been analyzed to identify the signatures of density
J.-F. Cécile, P. Vila, E. Blanc
doaj   +1 more source

Density enhancements associated with equatorial spread F [PDF]

Annales Geophysicae, 2010
Forces governing the three-dimensional structure of equatorial spread-F (ESF) plumes are examined using the NRL SAMI3/ESF three-dimensional simulation code.
J. Krall, J. D. Huba, G. Joyce, T. Yokoyama   +3 more
doaj   +1 more source

Equatorial spread-F forecasting model with local factors using the long short-term memory network

Earth, Planets and Space, 2023
The predictability of the nighttime equatorial spread-F (ESF) occurrences is essential to the ionospheric disturbance warning system. In this work, we propose ESF forecasting models using two deep learning techniques: artificial neural network (ANN) and ...
Phimmasone Thammavongsy, Pornchai Supnithi, Lin Min Min Myint, Kornyanat Hozumi, Donekeo Lakanchanh   +4 more
doaj   +1 more source

Global Modeling of Equatorial Spread F with SAMI3/WACCM‐X

Geophysical Research Letters, 2020
We report the first results of a global ionosphere/thermosphere simulation study that self‐consistently generates large‐scale equatorial spread F (ESF) plasma bubbles in the postsunset ionosphere.
J. D. Huba, H.‐L. Liu
doaj   +1 more source

Multi-instrumented observations of the equatorial F-region during June solstice: large-scale wave structures and spread-F

Progress in Earth and Planetary Science, 2018
Typical equatorial spread-F events are often said to occur during post-sunset, equinox conditions in most longitude sectors. Recent studies, however, have found an unexpected high occurrence of ionospheric F-region irregularities during June solstice ...
Fabiano S. Rodrigues, Dustin A. Hickey, Weijia Zhan, Carlos R. Martinis, Bela G. Fejer, Marco A. Milla, Juan F. Arratia   +6 more
doaj   +1 more source

Letter to the Editor: Post-midnight onset of spread-F at Kodaikanal during the June solstice of solar minimum [PDF]

Annales Geophysicae, 1999
At dip equatorial stations in the Indian zone, spread-F conditions are known to develop preferentially around midnight during the June solstice (northern summer) months of low solar activity, in association with a distinct increase in F layer height ...
J. H. Sastri
doaj   +1 more source

Nonlinear equatorial spread F

Geophysical Research Letters, 1976
A numerical simulation of the non‐linear evolution of the collisional Rayleigh‐Taylor instability using a set of equations appropriate for the equatorial F region ionosphere has been performed. Our results show that the irregularities produced by the instability grow on the bottomside of the F region peak, as predicted by linear theory, and then the ...
Anthony J. Scannapieco, Sidney L. Ossakow   +1 more
openaire   +1 more source