A theoretical study of the ligand-exchange reactions of Na+·X complexes (X=O,O2,N2,CO2 and H2O): implications for the upper atmosphere

Daire, Sophia E.; Plane, J. M. C.; Gamblin, Stuart D.; Soldán, Pavel; Lee, Edmond P. F.; Wright, Timothy G.

doi:10.1016/s1364-6826(02)00130-x

Cited by 26 publications

(25 citation statements)

References 34 publications

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“…The altitude envelope (∼88–99 km), where enhanced Na/sporadic layers exist and the electron concentration is remarkably less, is where the recombination region of Na + ions occurs. As discussed in Daire et al [2002], the lifetime of Na + ions below 100 km is on the order of a few minutes. Therefore, recombination of Na + ions results in the enhancement of Na atoms and a reduction in the electron concentration in that altitude range.…”

Section: Discussionmentioning

confidence: 95%

“…Such layers often form when ionization from higher altitude descends down to the E region due to tidal influence [ Mathews and Bekeny , 1979]. Even though neutralization is fast around 90 km since the lifetimes of Na + at these altitudes are less than a minute [ Daire et al , 2002], descending layers or advection of plasma can result in the sporadic E lasting for a few hours. Such rapid neutralization results in Sporadic Na layers and hence we see a hole in the plasma.…”

Section: Discussionmentioning

confidence: 99%

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Identification of large‐scale billow‐like structure in the neutral sodium layer over Arecibo

Sarkhel¹,

Raizada²,

Mathews³

et al. 2012

J. Geophys. Res.

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[1] We present a rare event that was recorded over Arecibo using sodium (Na) lidar. Billow-like structures with periods of $60 min were seen in the Na layer above 102 km on the night of 7-8 July 2010. The absence of any high-altitude structure was noted on the following night. Spectral analysis using the Lomb-Scargle technique reveals periods with larger power on the first night as compared to the adjacent one. The keograms derived from a sequence of 557.7 nm airglow images show the passage of a large frontal wave on 7-8 July 2010. Further investigation on the occurrence of neutral instabilities was carried out using mesospheric temperature and horizontal wind obtained from the Sounding of Atmosphere using Broadband Emission Radiometry (SABER) and TIMED Doppler Interferometer (TIDI) instruments onboard the TIMED satellite. A good agreement is observed between the temperatures derived from SABER and ground-based airglow instruments. The mesospheric temperature and horizontal wind profiles allowed the determination of square of the Brunt-Väisälä frequency and Richardson number to quantitatively evaluate the possible role of different instabilities in generating this structure. The profile of the former entity reveals that the region is convectively stable during the time when the event was observed. However, the presence of strong shears in the region, where billow-like structures are observed on 7-8 July 2010, is noted along with a Richardson number of 0.22, indicating the likely occurrence of dynamical instability. Thus, the present work suggests that dynamical instability make conditions conducive for billow-like structures in the Na layer above 102 km. The possible role of plasma processes in generating these structures is also discussed.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Identification of large‐scale billow‐like structure in the neutral sodium layer over Arecibo

Sarkhel¹,

Raizada²,

Mathews³

et al. 2012

J. Geophys. Res.

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“…The false color background gradient in Figure 6a schematically underscores the complex chemical/dynamical interplay in producing the Na distribution in the MLT. As the lifetime of Na + ions below 90 km is a few seconds (Daire et al 2002), the recombination of Na + ions and electrons produces neutral Na atoms which are then embedded into the background atmosphere. Thereafter, the neutral Na layer follows the background atmosphere wherein dynamics plays major role.…”

Section: Role Of Sporadic-e Activitymentioning

confidence: 99%

“…In the intermediate altitude region (90 to 100 km), we encounter the most complex interaction with both neutral Na and Na ions playing comparable roles. The lifetime of Na + ions ranges from a few minutes to tens of minutes (Daire et al 2002). Therefore, the neutral Na layer will have a limited memory of E S where the presence of sufficient wind shear can generate E S layers (e.g.…”

Section: Role Of Sporadic-e Activitymentioning

confidence: 99%

A case study on occurrence of an unusual structure in the sodium layer over Gadanki, India

et al. 2015

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The height-time-concentration map of neutral sodium (Na) atoms measured by a Na lidar during the night of 18 to 19 March 2007 over Gadanki, India (13.5°N, 79.2°E) reveals an unusual structure in the Na layer for around 30 min in the altitude range of 92 to 98 km which is similar to the usual 'C' type structures observed at other locations. In order to understand the physical mechanism behind the generation of this unusual event, an investigation is carried out combining the data from multiple instruments that include the meteor wind radar over Thiruvananthapuram, India (8.5°N, 77°E) and the SABER instrument onboard the TIMED satellite. The temperature and wind profiles from the data set provided by these instruments allow us to infer the Richardson number which is found to be noticeably less than the canonical threshold of 0.25 above 92 km over Thiruvananthapuram suggesting the plausible generation of Kelvin-Helmholtz (KH) billows over southwestern part of the Indian subcontinent. Based on the average wind speed and direction over Thiruvananthapuram, it is proposed that the KH-billow structure was modified due to the background wind and was advected with it in nearly 'frozen-in' condition (without significant decay) in the northeastward direction reaching the Na lidar location (Gadanki). This case study, therefore, presents a scenario wherein the initially deformed KH-billow structure survived for a few hours (instead of a few minutes or tens of minutes as reported in earlier works) in an apparently 'frozen-in' condition under favorable background conditions. In this communication, we suggest a hypothesis where this deformed KH-billow structure plays crucial role in creating the abovementioned unusual structure observed in the Na layer over Gadanki.

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“…Second, both Na s and sporadic E layer ( E s ) show downward progression most of the time, implicating their close relation to the tidal and/or gravity waves. The most widely accepted mechanism of Na s above 100 km is the neutralization of the elevated Na + within a sporadic E layer (Daire et al, ; Williams et al, , ; Yuan, Wang, et al, ). This mechanism is quite feasible within the lower E region, especially below 100 km, as the E s travels to lower altitude, where the surrounding atmospheric density and pressure increase dramatically.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Investigation on Tidal and Gravity Wave Contributions to the Summer Time Na Variations in the Midlatitude E Region

2017

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The Na density variations in the E region have been studied over the past few decades. Although considerable progress in understanding and in modeling the metal layer observations has been made, Na density features above 100 km have yet to be explained. Various studies have linked them to the Na+ variations, a major reservoir for Na in E region. But the lack of comprehensive modeling investigations and of wind and temperature observations prevents further understanding on this important ion‐neutral coupling topic. In this study, we conduct a numerical simulation on the summer time Na density behavior in the midlatitude E region, where both the ion density and the neutral atmosphere are modulated by tidal and gravity waves. Simulation results show good agreement with Na lidar measurements and reveal that atmospheric waves can transport Na upward to generate Na layers and variations in E region considerably. The vertical wind component of the large amplitude tidal wave can extend the Na layer above 120 km into the thermosphere. The simulation also demonstrates that the modulation of large amplitude gravity (GW) wave can generate small‐scale sporadic Na layers (Nas) in the E region. Finally, eddy diffusion enhancement in the GW saturation process can significantly alter the Nas spatial and temporal structures.

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A theoretical study of the ligand-exchange reactions of Na+·X complexes (X=O,O2,N2,CO2 and H2O): implications for the upper atmosphere

Cited by 26 publications

References 34 publications

Identification of large‐scale billow‐like structure in the neutral sodium layer over Arecibo

Identification of large‐scale billow‐like structure in the neutral sodium layer over Arecibo

A case study on occurrence of an unusual structure in the sodium layer over Gadanki, India

A Numerical Investigation on Tidal and Gravity Wave Contributions to the Summer Time Na Variations in the Midlatitude E Region

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