Bibliography

Total Electron Content Variations during an HSS/CIR driven storm at high and middle latitudes

Geethakumari, Gopika; Aikio, Anita; Cai, Lei; Vanhamaki, Heikki; Pedersen, Marcus; Coster, Anthea; Marchaudon, Aurélie; Blelly, Pierre-Louis; Haberle, Veronika; Maute, Astrid; Ellahouny, Nada; Virtanen, Ilkka; Norberg, Johannes; Soyama, Shin-Ichiro; Grandin, Maxime;

Published by:       Published on: mar

YEAR: 2022     DOI: 10.5194/egusphere-egu22-8194

Seasonal Variation of Thermospheric Composition Observed by NASA GOLD

We examine characteristics of the seasonal variation of thermospheric composition using column number density ratio ∑O/N2 observed by the NASA Global Observations of Limb and Disk (GOLD) mission from low-mid to mid-high latitudes. We also use ∑O/N2 derived from the Global Ultraviolet Imager (GUVI) limb measurements onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and estimated by the NRLMSISE-00 empirical model to aid our investigation. We found that the ∑O/N2 seasonal variation is hemispherically asymmetric: in the southern hemisphere, it exhibits the well-known annual and semiannual pattern, with highs near the equinoxes, and primary and secondary lows near the solstices. In the northern hemisphere, it is dominated by an annual variation, with a minor semiannual component with the highs shifting toward the wintertime. We also found that the durations of the December and June solstice seasons in terms of ∑O/N2 are highly variable with longitude. Our hypothesis is that ion-neutral collisional heating in the equatorial ionization anomaly region, ion drag, and auroral Joule heating play substantial roles in this longitudinal dependency. Finally, the rate of change in ∑O/N2 from one solstice season to the other is dependent on latitude, with more dramatic changes at higher latitudes.

Qian, Liying; Gan, Quan; Wang, Wenbin; Cai, Xuguang; Eastes, Richard; Yue, Jia;

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

YEAR: 2022     DOI: 10.1029/2022JA030496

annual variation; GOLD observation; MSIS; seasonal variation; semiannual variation; thermosphere composition

Satellite In Situ Electron Density Observations of the Midlatitude Storm Enhanced Density on the Noon Meridional Plane in the F Region During the 20 November 2003 Magnetic Storm

Ionospheric storm enhanced density (SED) has been extensively investigated using total electron content deduced from GPS ground and satellite-borne receivers. However, dayside in situ electron density measurements have not been analyzed in detail for SEDs yet. We report in situ electron density measurements of a SED event in the Northern Hemisphere (NH) at the noon meridian plane measured by the Challenging Minisatellite Payload (CHAMP) polar-orbiting satellite at about 390 km altitude during the 20 November 2003 magnetic storm. The CHAMP satellite measurements render rare documentation about the dayside SED s life cycle at a fixed magnetic local time (MLT) through multiple passes. Solar wind drivers triggered the SED onset and controlled its lifecycle through its growth and retreat phases. The SED electron density enhancement extended from the equatorial ionization anomaly to the noon cusp. The midlatitude electron density increased to a maximum at the end of the growth phase. Afterward, the dayside SED region retreated gradually to lower magnetic latitudes. The observations showed a hemisphere asymmetry, with the NH electron density exhibiting a more significant enhancement. The simulations using the Thermosphere Ionosphere Electrodynamic General Circulation model show a good agreement with the CHAMP observations. The simulations indicate that the dayside midlatitude electron density enhancement has a complicated dependence on vertical ion drift, neutral wind, magnetic latitude, MLT, and the height of the F2 layer. Finally, we discuss the notion of using the mean cross-polar cap electric field as a proxy for assessing the effects of solar wind drivers on producing midlatitude electron density enhancement.

Lin, Chin; Sutton, Eric; Wang, Wenbin; Cai, Xuguang; Liu, Guiping; Henney, Carl; Cooke, David;

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

YEAR: 2022     DOI: 10.1029/2021JA029831

in situ plasma density; ionospheric electron density; prompt penetration electric field; Storm enhanced density; tongue of ionization

Pronounced Suppression and X-Pattern Merging of Equatorial Ionization Anomalies After the 2022 Tonga Volcano Eruption

Following the 2022 Tonga Volcano eruption, dramatic suppression and deformation of the equatorial ionization anomaly (EIA) crests occurred in the American sector ∼14,000 km away from the epicenter. The EIA crests variations and associated ionosphere-thermosphere disturbances were investigated using Global Navigation Satellite System total electron content data, Global-scale Observations of the Limb and Disk ultraviolet images, Ionospheric Connection Explorer wind data, and ionosonde observations. The main results are as follows: (a) Following the eastward passage of expected eruption-induced atmospheric disturbances, daytime EIA crests, especially the southern one, showed severe suppression of more than 10 TEC Unit and collapsed equatorward over 10° latitudes, forming a single band of enhanced density near the geomagnetic equator around 14–17 UT, (b) Evening EIA crests experienced a drastic deformation around 22 UT, forming a unique X-pattern in a limited longitudinal area between 20 and 40°W. (c) Thermospheric horizontal winds, especially the zonal winds, showed long-lasting quasi-periodic fluctuations between ±200 m/s for 7–8 hr after the passage of volcano-induced Lamb waves. The EIA suppression and X-pattern merging was consistent with a westward equatorial zonal dynamo electric field induced by the strong zonal wind oscillation with a westward reversal.

Aa, Ercha; Zhang, Shun-Rong; Wang, Wenbin; Erickson, Philip; Qian, Liying; Eastes, Richard; Harding, Brian; Immel, Thomas; Karan, Deepak; Daniell, Robert; Coster, Anthea; Goncharenko, Larisa; Vierinen, Juha; Cai, Xuguang; Spicher, Andres;

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

YEAR: 2022     DOI: 10.1029/2022JA030527

EIA suppression and X-pattern; Equatorial ionization anomaly; GNSS TEC; GOLD UV images; ICON MIGHTI neutral wind; Tonga volcano eruption

Satellite in-situ electron density observations of the midlatitude storm enhanced density on the noon meridional plane in the F region during the 20 November 2003 magnetic storm

The GUVI measurements indicated that the atomic oxygen (O) to molecular nitrogen (N2) (2021a) used the TIMED/GUVI limb measurements and TIEGCM simulations to investigate

Lin, Chin; Sutton, Eric; Wang, Wenbin; Cai, Xuguang; Liu, Guiping; Henney, Carl; Cooke, David;

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

YEAR: 2022     DOI: 10.1029/2021JA029831

The nighttime ionospheric response and occurrence of equatorial plasma irregularities during geomagnetic storms: a case study

Recent studies revealed that the long-lasting daytime ionospheric enhancements of Total Electron Content (TEC) were sometimes observed in the Asian sector during the recovery phase of geomagnetic storms (e.g., Lei (J Geophys Res Space Phys 123: 3217–3232, 2018), Li (J Geophys Res Space Phys 125: e2020JA028238, 2020). However, they focused only on the dayside ionosphere, and no dedicated studies have been performed to investigate the nighttime ionospheric behavior during such kinds of storm recovery phases. In this study, we focused on two geomagnetic storms that happened on 7–8 September 2017 and 25–26 August 2018, which showed the prominent daytime TEC enhancements in the Asian sector during their recovery phases, to explore the nighttime large-scale ionospheric responses as well as the small-scale Equatorial Plasma Irregularities (EPIs). It is found that during the September 2017 storm recovery phase, the nighttime ionosphere in the American sector is largely depressed, which is similar to the daytime ionospheric response in the same longitude sector; while in the Asian sector, only a small TEC increase is observed at nighttime, which is much weaker than the prominent daytime TEC enhancement in this longitude sector. During the recovery phase of the August 2018 storm, a slight TEC increase is observed on the night side at all longitudes, which is also weaker than the prominent daytime TEC enhancement. For the small-scale EPIs, they are enhanced and extended to higher latitudes during the main phase of both storms. However, during the recovery phases of the first storm, the EPIs are largely enhanced and suppressed in the Asian and American sectors, respectively, while no prominent nighttime EPIs are observed during the second storm recovery phase. The clear north–south asymmetry of equatorial ionization anomaly crests during the second storm should be responsible for the suppression of EPIs during this storm. In addition, our results also suggest that the dusk side ionospheric response could be affected by the daytime ionospheric plasma density/TEC variations during the recovery phase of geomagnetic storms, which further modulates the vertical plasma drift and plasma gradient. As a result, the growth rate of post-sunset EPIs will be enhanced or inhibited.

Wan, Xin; Xiong, Chao; Gao, Shunzu; Huang, Fuqing; Liu, Yiwen; Aa, Ercha; Yin, Fan; Cai, Hongtao;

Published by: Satellite Navigation      Published on: nov

YEAR: 2021     DOI: 10.1186/s43020-021-00055-x

Equatorial plasma irregularity; Geomagneitc storm; Ionospheric response; longitudinal variations; Storm recovery phase

The response of middle thermosphere (~ 160 km) composition to the November 20 and 21, 2003 superstorm

Yu, Tingting; Wang, Wenbin; Ren, Zhipeng; Cai, Xuguang; Yue, Xinan; He, Maosheng;

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

YEAR: 2021     DOI:

The dominant composition on the O/N2 responses during a geomagnetic storm

Here, TIMED/GUVI limb measurements and TIEGCM simulations were used to investigate The consistency of O/N2 variations between GUVI observations and TIEGCM predictions

Yu, Tingting; Wang, Wenbin; Ren, Zhipeng; Cai, Xuguang;

Published by:       Published on:

YEAR: 2021     DOI:

The Response of Middle Thermosphere (∼160 km) Composition to the November 20 and 21, 2003 Superstorm

TIMED/GUVI limb measurements and first-principles simulations from the Thermosphere Ionosphere Electrodynamics Global Circulation Model (TIEGCM) are used to investigate thermospheric atomic oxygen (O) and molecular nitrogen (N2) responses in the middle thermosphere on a constant pressure surface (∼160 km) to the November 20 and 21, 2003 superstorm. The consistency between GUVI observations and TIEGCM simulated composition changes allows us to utilize TIEGCM outputs to investigate the storm-time behaviors of O and N2 systematically. Diagnostic analysis shows that horizontal and vertical advection are the two main processes that determine the storm-induced perturbations in the middle thermosphere. Molecular diffusion has a relatively smaller magnitude than the two advection processes, acting to compensate for the changes caused by the transport partly. Contributions from chemistry and eddy diffusion are negligible. During the storm initial and main phases, composition variations at high latitudes are determined by both horizontal and vertical advection. At middle-low latitudes, horizontal advection is the main driver for the composition changes where O mass mixing ratio decreases (N2 mass mixing ratio increases); whereas horizontal and vertical advection combined to dominate the changes in the regions where increases ( decreases). Over the entire storm period, horizontal advection plays a significant role in transporting high-latitude composition perturbations globally. Our results also demonstrate that storm-time temperature changes are not the direct cause of the composition perturbations on constant pressure surfaces.

Yu, Tingting; Wang, Wenbin; Ren, Zhipeng; Cai, Xuguang; Yue, Xinan; He, Maosheng;

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

YEAR: 2021     DOI: 10.1029/2021JA029449

atomic oxygen; GUVI limb observations; middle thermosphere; molecular nitrogen; storm-time perturbations; TIEGCM

Seasonal variation of O/N2 on different pressure levels from GUVI limb measurements

Yu, Tingting; Ren, Zhipeng; Le, Huijun; Wan, Weixing; Wang, Wenbin; Cai, Xuguang; Li, Xing;

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

YEAR: 2020     DOI:

On the responses of atomic oxygen at middle thermosphere (160 km) to the 20-21 November 2003 superstorm

Yu, Tingting; Wang, Wenbin; Ren, Zhipeng; Cai, Xuguang;

Published by:       Published on:

YEAR: 2020     DOI:

Comparison of GOLD nighttime measurements with total electron content: Preliminary results

The National Aeronautics and Space Administration (NASA) Global‐scale Observations of the Limb and Disk (GOLD) has been imaging the thermosphere and ionosphere since

Cai, Xuguang; Burns, Alan; Wang, Wenbin; Coster, Anthea; Qian, Liying; Liu, Jing; Solomon, Stanley; Eastes, Richard; Daniell, Robert; McClintock, William;

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

YEAR: 2020     DOI: 10.1029/2019JA027767

Initial observations by the GOLD mission

Given that previous measurements of ΔΣO/N 2 from low Earth orbit (LEO) have proven invaluable in advancing our understanding of the TI system (eg, TIMED/GUVI), GOLD data have

Eastes, RW; McClintock, WE; Burns, AG; Anderson, DN; Andersson, L; Aryal, S; Budzien, SA; Cai, X; Codrescu, MV; Correira, JT; , others;

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

YEAR: 2020     DOI: 10.1029/2020JA027823

Composition Changes Around the Equinoxes

Burns, Alan; Cai, Xuguang; Wang, Wenbin; Qian, Liying; Zhang, Yongliang; Eastes, Richard; McClintock, William;

Published by:       Published on:

YEAR: 2019     DOI:

Impacts of CME-induced geomagnetic storms on the midlatitude mesosphere and lower thermosphere observed by a sodium lidar and TIMED/GUVI

In this paper, we report our findings on the correlation between the neutral temperature (around the mesopause) and thermospheric column density O/N₂\ ratio, along with their response to geomagnetic storms above midlatitude of North America. A temperature/wind Doppler Na lidar, operating at Fort Collins, CO (41\textdegreeN, 105\textdegreeW), and later at Logan, UT (42\textdegreeN and 112\textdegreeW), observed significant temperature increases (temperature anomaly) above 95 km (as much as 55 K at 105 km altitude) during four coronal mass ejection-induced geomagnetic storms (April 2002, November 2004, May 2005, and October 2012). Coincident Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Spectrographic Imager observations indicate significant depletion in the thermospheric O/N₂\ ratio at the lidar locations. These observations suggest that the local mesopause warming seen by the lidar is due to transport of the high-latitude joule and particle heated neutrals at the\ E\ and\ F\ layers to the midlatitude region.

Yuan, T.; Zhang, Y.; Cai, X.; She, C.-Y.; Paxton, L.;

Published by: Geophysical Research Letters      Published on: 09/2015

YEAR: 2015     DOI: 10.1002/2015GL064860

Radar observations of simultaneous traveling ionospheric disturbances and atmospheric gravity waves

Simultaneous observations of atmospheric gravity waves (AGWs) and traveling ionospheric disturbances (TIDs) measured by an incoherent scatter radar at high latitudes are shown. The measurements were made using a beam swing experiment of the EISCAT UHF radar. The\ F\ region TID is seen as wavefronts in electron density, whereas the\ E\ region AGW is seen in the oscillations of the neutral wind. The wave vector of the TID has a downward component indicating that energy propagates upward. The periods of AGWs and TIDs are approximately the same (52\textendash57min), so it is concluded that the observed gravity wave in the\ E\ region propagates to the\ F\ region causing the TID there. Two interesting properties of the waves are observed. First, the neutral wind oscillations have an amplitude minimum at about 115km. It is suggested that this could be related to the minimum of the vertical refractive index around 120km. Second, in the course of time, the wave vector of the TID turns more in the downward direction, which leads to an increase in the horizontal wave length from 400 to 1450km. A possible explanation is that the background wind increases with altitude and turns the wavefronts more horizontal when distance from a stationary source increases. We suggest that the source is the sunrise terminator, since the horizontal direction of propagation of the TID in the morning hours is from the west, where both the auroral and thunderstorm activity are low.

en, Nygr\; Aikio, A.; Voiculescu, M.; Cai, L.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2014JA020794

atmospheric gravity wave; incoherent scatter; solar terminator; traveling ionospheric disturbance