Meteor radar quasi 2-day wave observations over 10 years at Collm (51.3° N, 13.0° E)

Lilienthal, Friederike; Jacobi, Ch.

doi:10.5194/acp-15-9917-2015

Cited by 36 publications

(34 citation statements)

References 41 publications

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“…The few previous studies either focused on the thermosphere/ionosphere, where the wave amplitudes are dominated by the temperature dependence of dissipative processes in the E‐region and tidal‐planetary wave interactions to imprint the planetary wave periods on this altitude regime (e.g., Forbes et al, 2018; Koval et al, 2018), or long‐term radar observations in the mesosphere. The former do not matter for the current question, and the latter are largely focused on the quasi‐2‐day wave (Q2DW) ranging from no correlation at northern midlatitudes (Lilienthal & Jacobi, 2015), to large positive correlation in the meridional wind but negative correlation with the zonal wind at subtropical NH latitudes (Gu et al, 2013), to small negative correlations at the equator (Rao et al, 2017). Moudden and Forbes (2014) found a positive Q2DW correlation with the solar cycle in SABER temperatures in the SH and no correlation in the NH, in contrast to Huang et al (2013) who reported a positive correlation in the SH and NH.…”

Section: Discussionmentioning

confidence: 99%

QBO, ENSO, and Solar Cycle Effects in Short‐Term Nonmigrating Tidal Variability on Planetary Wave Timescales From SABER—An Information‐Theoretic Approach

Kumari

Oberheide

2020

JGR Atmospheres

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Much progress has been made in delineating and understanding the “tidal climate” of the mesosphere and lower thermosphere, that is, tidal variability on seasonal or longer timescales. Short‐term tidal variability on timescales of a few days is much less understood, mainly due to observational constraints imposed by satellite local solar time sampling. This paper presents a new approach to study the “tidal weather” in 16 years of SABER temperatures. Our focus is on the eastward‐propagating nonmigrating diurnal tide with zonal wave number 3 (DE3) that originates from tropical convection. The statistics of short‐term tidal variability derived from “tidal deconvolution” are analyzed using an information‐theoretic approach based on Bayesian statistics and time‐dependent probability density functions. The paper particularly discusses the statistical characteristics of interannual changes in short‐term DE3 variability on a quasi‐10‐day wave (Q10DW) timescale and relates it to various forcing and propagation conditions such as Quasi‐Biennial Oscillation (QBO), El Niño‐Southern Oscillation (ENSO), and solar cycle. Understanding the response to these drivers requires a separate treatment of symmetric and antisymmetric DE3 tidal modes. Symmetric DE3 mode variability is enhanced during the easterly phase of the QBO due to enhanced Q10DW activity and during the La Niña phase of ENSO due to enhanced convective forcing but does not show a solar cycle dependence because of stable polar vortex conditions in the southern hemisphere. Antisymmetric DE3 mode variability is enhanced in the westerly phase of the QBO during solar maximum due to Q10DW activity related to a more unstable polar vortex in the northern hemisphere.

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Section: Discussionmentioning

confidence: 99%

QBO, ENSO, and Solar Cycle Effects in Short‐Term Nonmigrating Tidal Variability on Planetary Wave Timescales From SABER—An Information‐Theoretic Approach

Kumari

Oberheide

2020

JGR Atmospheres

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“…McCormack et al () found that the QTDW may be forcing in both the tropical and extratropical regions related to baroclinic/barotropic instability during the sudden stratospheric warming (SSW). Lilienthal and Jacobi () found that summer QTDW in the mesosphere is amplified after a maximum of zonal wind shear. Combining the two mechanisms, QTDWs may be a near‐resonant mode excited by baroclinic instability.…”

Section: Introductionmentioning

confidence: 99%

“…The quasi-two day wave (QTDW) is one of the dominant features in the mesosphere and lower thermosphere typically maximizing after the solstices. There are many observation reports on QTDW by radars (Gu, Li, Dou, Wang, et al, 2013;Harris & Vincent, 1993;Lilienthal & Jacobi, 2015;Ma et al, 2017;Meek et al, 1996;Muller, 1972;Nozawa et al, 2003;Pancheva, 2006) and satellites (Gu, Li, Dou, Wu, et al, 2013;Lieberman, 1999;Rodgers & Prata, 1981;Wu et al, 1993). The observed dominant QTDWs are mainly westward propagating with zonal wave numbers 3 (W3) and 4 (W4), which are strong in the Southern Hemisphere (SH) and Northern Hemisphere (NH), respectively (Gu, Li, Dou, Wu, et al, 2013;Tunbridge et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Two Day Wave Traveling Westward With Wave Number 1 During the Sudden Stratospheric Warming in January 2017

et al. 2018

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Quasi‐two day wave propagating westward with wave number 1 (W1) in January 2017 is studied using global temperature observed by Sounding of the Atmosphere using Broadband Emission Radiometry and wind observed by a meteor radar at Fuke, China (19.0°N, 109.8°E). The amplitude of W1 significantly enhances during January 2017, when two stratospheric warming events occur. The temperature perturbation of W1 reaches maximum amplitude of more than 6 K at latitude ±15° around ~84 km and ~95 km. The structure of temperature W1 is symmetric with regard to the equator. The temporal variation of W1 is consistent with the stationary planetary wave with wave number 2 (SPW2), but contrary to the quasi‐two day wave propagating westward with wave number 3 (W3). When SPW2 is large during two sudden stratospheric warming events, energy transfers from W3 to W1. Two bursts of the 2 day wave in meridional wind observed by the meteor radar are just corresponding to the local maxima of W3 and W1, respectively. We conclude that during January 2017, W1 is generated by the nonlinear interaction between SPW2 and W3. SPW2 which is modulated by the quasi‐16 day perturbation in the stratosphere plays a key role in the energy transmission from W3 to W1, and it is responsible for the 16 day variation of W1.

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“…The 16 year horizontal wind observations from medium‐frequency radar show that the QTDW in January also tends to peak at ~48 h [ Gu et al , ]. In addition, it was also found that the periods of the QTDW in boreal summer are more distributed and variable ranging from ~40 to 60 h [ Harris , ; Gu et al , ; Lilienthal and Jacobi , ]. Nevertheless, the reasons for the variability of the QTDW period are not clear yet.…”

Section: Introductionmentioning

confidence: 99%

The quasi‐2 day wave activities during 2007 boreal summer period as revealed by Whole Atmosphere Community Climate Model

Liu

Pedatella

et al. 2016

JGR Space Physics

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The ensemble data assimilation version of the Whole Atmosphere Community Climate Model + Data Assimilation Research Testbed developed at National Center for Atmospheric Research is utilized to study the quasi‐2 day wave (QTDW) activities during boreal summer period of 2007. The westward wave number 3 (W3) and 4 (W4) modes intermittently dominated the QTDW oscillations at different times. The W3 peaked 4 times from day 172 to day 224 with the major peak at around days 199–206 being much stronger than the others. The W4 also showed a quadruple structure during the whole summer period but with their amplitudes comparable with each other. The period of W4 increases from ~42 h on day 186 (with stronger easterly jet) to 56 h on day 225 (with weaker easterly jet), while the W3 period is more stable with the maximum perturbation occurring at ~52 h. Thus, the W3 exhibits more normal mode features than W4. Further diagnostic analysis shows that the barotropically/baroclinically unstable regions at middle and low latitudes are more effective for the amplification of W3 with stronger instabilities providing larger forcing. Moreover, the temporal variability of the refractive indexes and critical layers of W4, which are related to the background wind, are responsible for its period variations. We also find that the absence of a westward wave number 2 (W2) QTDW during boreal summer of 2007 is due to the weaker easterly jet compared with that during austral summer.

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Meteor radar quasi 2-day wave observations over 10 years at Collm (51.3° N, 13.0° E)

Cited by 36 publications

References 41 publications

QBO, ENSO, and Solar Cycle Effects in Short‐Term Nonmigrating Tidal Variability on Planetary Wave Timescales From SABER—An Information‐Theoretic Approach

QBO, ENSO, and Solar Cycle Effects in Short‐Term Nonmigrating Tidal Variability on Planetary Wave Timescales From SABER—An Information‐Theoretic Approach

Two Day Wave Traveling Westward With Wave Number 1 During the Sudden Stratospheric Warming in January 2017

The quasi‐2 day wave activities during 2007 boreal summer period as revealed by Whole Atmosphere Community Climate Model

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