Latitudinal variations in the nocturnal behaviour of OI 630 nm airglow emissions and their relationship with equatorial electrodynamics

Saha, Sovan; Pallamraju, Duggirala

doi:10.1016/j.jastp.2022.105965

Cited by 4 publications

(3 citation statements)

References 33 publications

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“…During major storms, ∼12°–15° poleward shifts in the EIA crests were observed (e.g., Mannucci et al., 2005; Rout et al., 2019; Tsurutani et al., 2008). The shifts in the crest latitudes depend on the equatorial electric fields (Karan et al., 2016; Karan & Pallamraju, 2018; Saha & Pallamraju, 2022) that get stronger due to storm induced PPEF. Tulasi Ram et al., 2008 and Basu et al., 2010 have reported the prompt penetration of eastward electric fields into low and equatorial latitudes where the local time corresponds to postsunset hours during the entire main phase of the storm.…”

Section: Resultsmentioning

confidence: 99%

GOLD Mission's Observation About the Geomagnetic Storm Effects on the Nighttime Equatorial Ionization Anomaly (EIA) and Equatorial Plasma Bubbles (EPB) During a Solar Minimum Equinox

et al. 2023

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The equatorial ionization anomaly (EIA) (also known as the Appleton Anomaly) is a persistent ionospheric feature at equatorial and low latitudes (Appleton, 1946). The equatorial F region eastward electric fields ⃖⃖ ⃗ and horizontal northward magnetic fields ( 𝐴𝐴 ⃖⃖ ⃗ 𝐵𝐵 ) create a vertical, upward ( 𝐴𝐴 ⃖⃖ ⃗ 𝐸𝐸𝐸𝐸 ⃖⃖ ⃗ 𝐵𝐵 ) drift over the magnetic equator. Due to this vertical drift, the ionospheric plasma moves to higher altitudes and diffuses along the magnetic field lines to low latitudes. The overall effect is known as the fountain effect (Hanson & Moffett, 1966;Martyn, 1955). The plasma density shows a minimum at the magnetic equator and two maxima around 15°-20° north and south of it. This creates a double-peaked structure in the latitudinal distribution of the F region plasma with crests on each side and a trough over the magnetic equator, which is called the EIA.During geomagnetic disturbances, several storm-induced electric fields (e.g., prompt penetration electric field [PPEF], disturbance dynamo electric fields [DDEF]) contribute to the ionospheric electric fields over the equatorial and low latitude regions. During southward conditions of interplanetary magnetic field (IMF) Bz, effects of the Y-component (dawn-dusk) of interplanetary electric field (IEF) can reach equatorial and low latitudes. The

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Section: Resultsmentioning

confidence: 99%

GOLD Mission's Observation About the Geomagnetic Storm Effects on the Nighttime Equatorial Ionization Anomaly (EIA) and Equatorial Plasma Bubbles (EPB) During a Solar Minimum Equinox

et al. 2023

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“…The upper atmosphere shows different kinds of variability associated with neutral winds (e.g., Abdu et al., 2006; Gurubaran et al., 1995; Jyoti et al., 2004; Kumar et al., 2022; Meriwether et al., 1985) and electrodynamics (e.g., Karan & Pallamraju, 2017; Karan et al., 2016; Pallamraju et al., 1996; Saha & Pallamraju, 2022). The atmospheric waves have a significant impact on the upper atmosphere at different altitudes (Mandal & Pallamraju, 2020; Mandal et al., 2022; Miyoshi et al., 2014; Singh & Pallamraju, 2017; Vadas, 2007; Yiğit & Medvedev, 2009).…”

Section: Introductionmentioning

confidence: 99%

OI 630.0 nm Post‐Sunset Emission Enhancement as an Effect of Tidal Activity Over Low‐Latitudes

Saha,

Pallamraju,

Kumar

et al. 2024

JGR Space Physics

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The OI 630.0 nm airglow emission variability provides salient information on the dynamical changes taking place in the upper atmosphere at around 250 km. The emission rates vary with the changes in the ambient electron densities and the neutral constituents that are associated with these emissions. On several occasions, enhancements in these emissions are observed during post‐sunset hours, around 21 local time (LT), as measured from Mt. Abu (24.6°N, 72.7°E, 19°N Mag), a low‐latitude location at Indian longitudes. These enhancements occur following the typical monotonic decrease in emission intensity after sunset. The presence of poleward meridional wind preceded by cessation and reversal of equatorward wind at the post‐sunset hours was shown to be the cause for such observed emission enhancements in an earlier study. In this study, the cause of such reversal in meridional winds during post‐sunset hours has been investigated using the variation in electron densities and meridional winds simulated by the Whole Atmosphere Community Climate Model with thermosphere‐ionosphere eXtension (WACCM‐X), which also shows enhancements in electron densities similar to those observed in the post‐sunset OI 630.0 nm nightglow emissions, and simultaneous reversal in meridional winds as well. The amplitudes and phases of different components of tides obtained from WACCM‐X meridional winds reveal a significant contribution of higher‐order tides, especially, quarter‐diurnal tides, to the observed reversal in the meridional winds during post‐sunset hours.

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“…The upper atmosphere shows different kinds of variability associated with neutral winds (e.g., Meriwether et al, 1985;Gurubaran et al, 1995;Jyoti et al, 2004;Abdu et al, 2006;Kumar et al, 2022) and electrodynamics (e.g., Pallamraju et al, 1996;Karan et al, 2016;Karan and Pallamraju, 2017;Saha and Pallamraju, 2022). The atmospheric waves have a significant impact on the upper atmosphere at different altitudes (Vadas, 2007;Yigit and Medevdev, 2009;Miyoshi et al, 2014;Singh and Pallamraju, 2017;Mandal et al, 2020;.…”

Section: Introductionmentioning

confidence: 99%

OI 630.0 nm Post-Sunset Emission Enhancement as an Effect of Tidal Activity over Low-Latitudes

Saha

Pallamraju

Kumar

et al. 2023

Preprint

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The OI 630.0 nm airglow emission variability provides salient information of the dynamical changes taking place in the upper atmosphere at around 250 km altitudinal region. The emission rates vary with the changes in the ambient electron densities and the neutral constituents which are associated with these emissions. On several occasions enhancements in these emissions are observed during post-sunset hours as measured from Mt. Abu (24.6oN, 72.7oE, 19oN Mag), a low-latitude location in the Indian longitude sector. These enhancements occur following the typical monotonic decrease in emission intensity after sunset. The presence of poleward meridional wind was shown to be the cause for such observed emission enhancements. However, climatologically, meridional winds are equatorward during these times. In this study, the cause of such reversal in winds in the post-sunset hours has been investigated using the variation in electron densities and winds simulated by the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCM-X) which also shows enhancements similar to those observed in the post-sunset OI 630.0 nm nightglow emissions. The amplitudes and phases of different components of tides obtained in WACCM-X meridional winds reveal a significant contribution of quarter-diurnal tides to be responsible for the observed reversal in the meridional winds during post-sunset hours. The change in the tidal amplitudes is proportional to the changes in wind magnitude during that wind reversal.

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Latitudinal variations in the nocturnal behaviour of OI 630 nm airglow emissions and their relationship with equatorial electrodynamics

Cited by 4 publications

References 33 publications

GOLD Mission's Observation About the Geomagnetic Storm Effects on the Nighttime Equatorial Ionization Anomaly (EIA) and Equatorial Plasma Bubbles (EPB) During a Solar Minimum Equinox

GOLD Mission's Observation About the Geomagnetic Storm Effects on the Nighttime Equatorial Ionization Anomaly (EIA) and Equatorial Plasma Bubbles (EPB) During a Solar Minimum Equinox

OI 630.0 nm Post‐Sunset Emission Enhancement as an Effect of Tidal Activity Over Low‐Latitudes

OI 630.0 nm Post-Sunset Emission Enhancement as an Effect of Tidal Activity over Low-Latitudes

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