Bibliography

Implication of Tidal Forcing Effects on the Zonal Variation of Solstice Equatorial Plasma Bubbles

Equatorial plasma bubbles (EPBs) are plasma depletions that can occur in the nighttime ionospheric F region, causing scintillation in satellite navigation and communications signals. Past research has shown that EPB occurrence rates are higher during the equinoxes in most longitude zones. An exception is over the central Pacific and African sectors, where EPB activity has been found to maximize during solstice. Tsunoda et al. (2015) hypothesized that the solstice maxima in these two sectors could be driven by a zonal wavenumber 2 atmospheric tide in the lower thermosphere. In this study, we utilize satellite observations to examine evidence of such a wave-2 feature preconditioning the nighttime ionosphere to favor higher EPB growth rates over these two regions. We find the postsunset total electron content (TEC) observed by FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) during boreal summer from 2007 to 2012 exhibits a wave-2 zonal distribution, consistent with elevated vertical plasma gradients favorable for EPB formation. Numerical experiments are also carried out to determine whether such an ionospheric wave-2 can be produced as a result of vertical coupling from atmospheric tides with zonal wavenumber 2 in the local time frame. We find that forcing from these tidal components produced increases in the Rayleigh-Taylor growth rate over both sectors during solar maximum and minimum, as well as wave-2 modulations on vertical ion drift, ion flux convergence, and nighttime TEC. Our results are consistent with the aforementioned hypothesis over both regions with vertical coupling effects from atmospheric tides preconditioning the nighttime ionosphere to favor higher EPB growth rates.

Chang, Loren; Salinas, Cornelius; Chiu, Yi-Chung; , Jones; Rajesh, P.; Chao, Chi-Kuang; Liu, Jann-Yenq; Lin, Charles; Hsiao, Tung-Yuan;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028295

Ionosphere; Atmospheric tides; equatorial plasma bubble; scintillation; vertical coupling; wind dynamo

Impacts of SABER CO ₂ -based eddy diffusion coefficients in the lower thermosphere on the ionosphere/thermosphere

This work estimates global-mean K_zz using Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics monthly global-mean CO₂ profiles and a one-dimensional transport model. It is then specified as a lower boundary into the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). Results first show that global-mean CO₂ in the mesosphere and lower thermosphere region has annual and semiannual oscillations (AO and SAO) with maxima during solstice seasons along with a primary maximum in boreal summer. Our calculated AO and SAO in global-mean CO₂ are then modeled by AO and SAO in global-mean K_zz. It is then shown that our estimated global-mean K_zz is lower in magnitude than the suggested global-mean K_zz from Qian et al. (2009) that can model the observed AO and SAO in the ionosphere/thermosphere (IT) region. However, our estimated global-mean K_zz is similar in magnitude with recent suggestions of global-mean K_zz in models with explicit gravity wave parameterization. Our work therefore concludes that global-mean K_zz from global-mean CO₂ profiles cannot model the observed AO and SAO in the IT region because our estimated global-mean K_zz may only be representing eddy diffusion due to gravity wave breaking. The difference between our estimated global-mean K_zz and the global-mean K_zz from Qian et al. (2009) thus represents diffusion and mixing from other nongravity wave sources not directly accounted for in the TIE-GCM lower boundary conditions. These other sources may well be the more dominant lower atmospheric forcing behind the AO and SAO in the IT region.

Salinas, Cornelius; Chang, Loren; Liang, Mao-Chang; Yue, Jia; Russell, James; Mlynczak, Martin;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2016

YEAR: 2016     DOI: 10.1002/2016JA023161

Impacts of SABER CO2-based eddy diffusion coefficients in the lower thermosphere on the ionosphere/thermosphere

This work estimates global‐mean K zz using Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics

Salinas, Cornelius; Chang, Loren; Liang, Mao-Chang; Yue, Jia; , Russell; Mlynczak, Martin;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2016     DOI: 10.1002/2016JA023161