Effects of Latitude-Dependent Gravity Wave Source Variations on the Middle and Upper Atmosphere

Yiğit, Erdal; Medvedev, Alexander S.; Ern, Manfred

doi:10.3389/fspas.2020.614018

Cited by 28 publications

(23 citation statements)

References 104 publications

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“…The simulated large wind shear peak varies with the season at middle to high latitudes: higher during winter and lower during summer, consistent with the seasonal variation of the mesopause height. Recently Yiǧit et al (2021) have used the Coupled Middle Atmosphere Thermosphere-2 GCM to study the importance of latitudinal variability in the GW sources for the middle and upper atmosphere. Pedatella and Liu (2018) implemented atmospheric variability into the model study of the atmosphere and ionosphere system to one particular geomagnetic storm.…”

Section: Gravity Wavesmentioning

confidence: 99%

Ionosphere Influenced From Lower-Lying Atmospheric Regions

Knížová

Laštovička

Kouba

et al. 2021

Front. Astron. Space Sci.

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The ionosphere represents part of the upper atmosphere. Its variability is observed on a wide-scale temporal range from minutes, or even shorter, up to scales of the solar cycle and secular variations of solar energy input. Ionosphere behavior is predominantly determined by solar and geomagnetic forcing. However, the lower-lying atmospheric regions can contribute significantly to the resulting energy budget. The energy transfer between distant atmospheric parts happens due to atmospheric waves that propagate from their source region up to ionospheric heights. Experimental observations show the importance of the involvement of the lower atmosphere in ionospheric variability studies in order to accurately capture small-scale features of the upper atmosphere. In the Part I Coupling, we provide a brief overview of the influence of the lower atmosphere on the ionosphere and summarize the current knowledge. In the Part II Coupling Evidences Within Ionospheric Plasma—Experiments in Midlatitudes, we demonstrate experimental evidence from mid-latitudes, particularly those based on observations by instruments operated by the Institute of Atmospheric Physics, Czech Academy of Sciences. The focus will mainly be on coupling by atmospheric waves.

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Section: Gravity Wavesmentioning

confidence: 99%

Ionosphere Influenced From Lower-Lying Atmospheric Regions

Knížová

Laštovička

Kouba

et al. 2021

Front. Astron. Space Sci.

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“…Whilst the focus of our study is not on the development of the GW parameterization (the focus is rather to provide a detailed decomposition of the migrating and non-migrating modes produced by the ExUM), it is nevertheless pertinent to discuss aspects of the GW parameterization here to aid future development. Particularly in the context of studies such as Ortland and Alexander (2006) and Yigit et al (2021).…”

Section: Migrating Modesmentioning

confidence: 99%

“…It was noted that the overall effects of gravity wave momentum forcing is highly dependent on the chosen gravity wave parameterization and chosen source spectrum. Yigit et al (2021) showed that implementing a latitudinally varying GW source spectrum can have a significant impact on middle atmosphere circulation, which can therefore have an important effect on the diurnal tides.…”

Section: Migrating Modesmentioning

confidence: 99%

“…It is also worth introducing here the importance of deposition of momentum by sub-grid scale non-orographic GWs, which must be accurately captured in parameterization schemes because of their important impact on tides in the MLT (e.g., Yigit and Medvedev, 2017;Miyahara and Forbes, 1991). For example, Yigit et al (2021) suggest that in order to reproduce observed middle atmosphere circulation, smaller than measured GW fluxes must be used at source level. Yigit and Medvedev (2017) also provide an extensive discussion into the influence of parameterized small-scale GWs on the migrating diurnal tide.…”

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confidence: 99%

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Analysis of Migrating and Non-Migrating Tides of the Extended Unified Model in the Mesosphere and Lower Thermosphere

Griffith

Mitchell

2021

Preprint

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Abstract. Atmospheric tides play a key role in coupling the lower, middle and upper atmosphere/ionosphere. The tides reach large amplitudes in the Mesosphere and Lower Thermosphere (MLT) where they can have significant fluxes of energy and momentum and so strongly influence the coupling and dynamics. The tides must therefore be accurately represented in Global Circulation Models (GCMs) that seek to model the coupling of atmospheric layers and impacts on the ionosphere. The tides consist of both migrating (sun-following) and non-migrating (not sun-following) components, both of which have important influences on the atmosphere. The Extended Unified Model (ExUM) is a recently developed version of the Met Office's Unified Model GCM which has been extended to include the MLT. Here, we present the first in-depth analysis of migrating and non-migrating modes in the ExUM. We show that the ExUM produces both non-migrating and migrating tides in the MLT of significant amplitude across a rich spectrum of spatial and temporal modes. The dominant non-migrating modes in the MLT are found to be the DE3, DW2 and DW3 in the diurnal tide and the S0, SW1 and SW3 in the semidiurnal tide. These modes can have monthly mean amplitudes at a height of 95 km as large as 35 ms−1 / 10 K. All the non-migrating modes exhibit a strong seasonal variability in amplitude and significant short-term variability is evident. Both the migrating and non-migrating modes exhibit notable variation with latitude. For example, the temperature and wind diurnal tides maximise at low latitudes and the semidiurnal tides include maxima at high latitudes. Our results demonstrate the capability of the ExUM for modelling atmospheric migrating and non-migrating tides and lays the foundation for its future development into a whole atmosphere model. To this end, we make specific recommendations on further developments which would improve the capability of the model.

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“…The dynamical and thermodynamical role of GWs in the vertical coupling between the lower and upper atmosphere is being increasingly studied in a global sense in a number of studies (Yiğit et al, 2016, and see the references therein). Numerical models of varying flavors are used to study GW processes in the atmosphere (e.g., Yiğit et al, 2009;Hickey et al, 2011;Heale et al, 2014;Gavrilov and Kshevetskii, 2015;Yiğit et al, 2021). Coarse-grid general circulation models require incorporation of GW models in order to account for subgrid-scale GW and to reproduce the variable and mean structure of the middle and upper atmosphere.…”

Section: Introductionmentioning

confidence: 99%

A Brief Overview of Gravity Wave Retrieval Techniques From Observations

Sakib

Yiğit

2022

Front. Astron. Space Sci.

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Atmospheric gravity waves (GWs) are important in driving the middle and upper atmosphere dynamics on Earth. Here, we provide a brief review of the most common techniques of retrieving gravity wave activity from observations. Retrieval of gravity wave activity from observations is a multi-step process. First, the background fields have to be removed as the retrieval of the wave activity highly depends on this. Second, since a broad spectrum of internal waves contributes to atmospheric fluctuations, the contribution of GWs has to be extracted carefully. We briefly discuss the strengths, limitations/barriers, and applications of each technique. We also outline some future research questions to improve the treatment of these wave extraction methods.

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Effects of Latitude-Dependent Gravity Wave Source Variations on the Middle and Upper Atmosphere

Cited by 28 publications

References 104 publications

Ionosphere Influenced From Lower-Lying Atmospheric Regions

Ionosphere Influenced From Lower-Lying Atmospheric Regions

Analysis of Migrating and Non-Migrating Tides of the Extended Unified Model in the Mesosphere and Lower Thermosphere

A Brief Overview of Gravity Wave Retrieval Techniques From Observations

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