Determination of Global Mean Eddy Diffusive Transport in the Mesosphere and Lower Thermosphere From Atomic Oxygen and Carbon Dioxide Climatologies

Swenson, G. R.; Salinas, Cornelius Csar Jude H.; Vargas, Fábio; Zhu, Yajun; Kaufmann, Martín; Jones, McArthur; Drob, Douglas P.; Liu, Alan; Yue, Jia; Yee, Jeng‐Hwa

doi:10.1029/2019jd031329

Cited by 16 publications

(21 citation statements)

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“…Several studies have reported the influence of gravity waves and turbulence on the T/I composition and calculated the eddy diffusion coefficient in the MLT region (Kirchhoff and Clemesha, 1983;Sasi and Vijayan, 2001;Swenson et al, 2019). Based on radar measurements, Kirchhoff and Clemesha (1983) calculated a minimum (maximum) eddy diffusion coefficient of 45 (123) m 2 s −1 during fall (summer).…”

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confidence: 99%

Role of eddy diffusion in the delayed ionospheric response to solar flux changes

Vaishnav¹,

Jacobi²,

Berdermann

et al. 2021

Ann. Geophys.

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Abstract. Simulations of the ionospheric response to solar flux changes driven by the 27 d solar rotation have been performed using the global 3-D Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) physics-based numerical model. Using the F10.7 index as a proxy for solar extreme ultraviolet (EUV) variations in the model, the ionospheric delay at the solar rotation period is well reproduced and amounts to about 1 d, which is consistent with satellite and in situ measurements. From mechanistic CTIPe studies with reduced and increased eddy diffusion, we conclude that the eddy diffusion is an important factor that influences the delay of the ionospheric total electron content (TEC). We observed that the peak response time of the atomic oxygen to molecular nitrogen ratio to the solar EUV flux changes quickly during the increased eddy diffusion compared with weaker eddy diffusion. These results suggest that an increase in the eddy diffusion leads to faster transport processes and an increased loss rate, resulting in a decrease in the ionospheric time delay. Furthermore, we found that an increase in solar activity leads to an enhanced ionospheric delay. At low latitudes, the influence of solar activity is stronger because EUV radiation drives ionization processes that lead to compositional changes. Therefore, the combined effect of eddy diffusion and solar activity leads to a longer delay in the low-latitude and midlatitude region.

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confidence: 99%

Role of eddy diffusion in the delayed ionospheric response to solar flux changes

Vaishnav¹,

Jacobi²,

Berdermann

et al. 2021

Ann. Geophys.

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“…Ultimately it may be necessary to relax the assumptions of Equation . This coupled with using eddy diffusion values at the TIE‐GCM lower boundary such as those deduced from satellite observations (e.g., Salinas et al., 2016; Swenson et al., 2019) or possibly those from the TIME‐GCM at the TIE‐GCM lower boundary pressure level (e.g., Figure 1c, Jones Jr. et al., 2017) may be warranted to improve the amplitude of the global climatological T‐I SAO. This work is outside the scope of the current paper, but we note that the TIE‐GCM does not need to consider more oxygen chemistry than it already does.…”

Section: Resultsmentioning

confidence: 99%

“…Figure3balso indicates that the TSM does have some downward influence on MLT oxygen chemistry over large spatial and seasonal time scales, consistent with the underlying assumptions of 1D modeling work interested in describing the vertical transport and photochemistry of species in the MLT region (e.g.,Allen et al, 1981;Colegrove et al, 1966;Salinas et al, 2016;Swenson et al, 2019). We therefore JONES ET AL.…”

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confidence: 98%

On the Effects of Mesospheric and Lower Thermospheric Oxygen Chemistry on the Thermosphere and Ionosphere Semiannual Oscillation

et al. 2021

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Our understanding of the dynamical, chemical, thermodynamical, electrodynamical, and diffusive processes that connect the chemical composition of the mesosphere/lower thermosphere (MLT) to the neutral and charged species in the overlying thermosphere-ionosphere (T-I) continues to evolve. Specifically, understanding the relative contributions of these different MLT processes and their effects on regulating the chemical constituents that contribute to T-I mass and electron density has important implications for specifying initial conditions for space weather forecasts (e.g., Pedatella & Liu, 2018). For example, T-I mass and electron density variations spanning timescales from a month to a year, or intra-annual variations (IAVs), have been observed since the 1930-1950s in the ionosphere and the 1960s in the thermosphere (e.g., Apple

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“…(2014) demonstrated that the CO 2 distribution above ∼80 km depends sensitively on the effective eddy diffusion coefficient. Furthermore, the values from WACCM (∼5–50 m 2 /s between 80 and 100 km) are found to be smaller than those determined from observations (Swenson et al., 2019), and those required for achieving agreement with various measurements of constituents (Feng et al., 2013; Garcia et al., 2014; Orsolini et al., 2017; Randall et al., 2015; Smith‐Johnsen et al., 2018).…”

Section: Introductionmentioning

confidence: 84%

“…Salinas et al (2016) derived eddy diffusion from SABER CO 2 measurement, and it is ∼33 m 2 /s at 90 km. Swenson et al (2019) obtained global mean eddy diffusion coefficient from O determined by SABER OH measurements, with odd oxygen loss considered, and the value is 33-60 m 2 /s between 90 and 95 km. This is smaller than the eddy diffusion coefficient from an earlier estimate without considering the odd oxygen loss (Swenson et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Effective Vertical Diffusion by Atmospheric Gravity Waves

Liu

2021

Geophysical Research Letters

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Gravity waves (GWs) play a critical role in transporting momentum, heat, and constituents throughout the atmosphere. Their effects need to be parameterized in general circulation models (GCMs), because GWs are a subgrid scale process (Alexander et al., 2010). This was demonstrated as being essential to model the zonal wind reversal and the anomalous winter-to-summer temperature gradient in the mesosphere/ mesopause region by Holton (1982, 1983), who used the linear saturation theory (Lindzen, 1981) to parameterize the drag by breaking GWs. It is also shown in later studies that GW drag is important for driving the stratospheric quasi-biennial oscillation (Baldwin et al., 2001) and the mesospheric semi-annual oscillation (Dunkerton, 1982; Sassi & Garcia, 1997). GW dissipation is found to induce a net heat flux, which has been determined from a linear theory (Walterscheid, 1981). This is in addition to the diffusion by turbulence induced by GW breaking as formulated in Lindzen (1981). The same idea applies to the transport of constituents, and the wave-induced heat/constituent flux has been formulated in terms of an effective eddy diffusion coefficient (Garcia et al., 2007; Gardner & Liu, 2010; A. Z. Liu, 2009). The formulation by Garcia et al. (2007) is applied in the Whole Atmosphere Community Climate Model (WACCM). Although diffusion from GW breaking is found to play a secondary role in tracer transport in comparison to advection (Holton & Schoeberl, 1988), WACCM simulations by Garcia et al. (2014) demonstrated that the CO 2 distribution above ∼80 km depends sensitively on the

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Determination of Global Mean Eddy Diffusive Transport in the Mesosphere and Lower Thermosphere From Atomic Oxygen and Carbon Dioxide Climatologies

Cited by 16 publications

References 74 publications

Role of eddy diffusion in the delayed ionospheric response to solar flux changes

Role of eddy diffusion in the delayed ionospheric response to solar flux changes

On the Effects of Mesospheric and Lower Thermospheric Oxygen Chemistry on the Thermosphere and Ionosphere Semiannual Oscillation

Effective Vertical Diffusion by Atmospheric Gravity Waves

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