Multiyear Observations of Gravity Wave Momentum Fluxes in the Midlatitude Mesosphere and Lower Thermosphere Region by Meteor Radar

Jia, Mingjiao; Xue, Xianghui; Gu, Sheng‐Yang; Chen, Tingdi; Ning, Baiqi; Wu, Jianfei; Zeng, Xiaoqing

doi:10.1029/2018ja025285

Cited by 20 publications

(24 citation statements)

References 53 publications

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“…Meteor radar operates both day and night under all kinds of weather and geographical conditions and provides good long-term observations; consequently, meteor radar is a powerful technique for studying the dynamics and climate of the mesopause region, including its wind fields and temperatures (e.g., Hocking et al, 2004;Holdsworth et al, 2006;Hall et al, 2006Hall et al, , 2012Stober et al, 2008Stober et al, , 2012Yi et al, 2016;Lee et al, 2016;Holmen et al, 2016;Liu et al, 2017;Lima et al, 2018;Ma et al, 2018). In addition to acquiring wind and temperature measurements, meteor radar has also been applied in recent years to estimate the atmospheric density in the mesopause region.…”

Section: Introductionmentioning

confidence: 99%

Climatology of the mesopause relative density using a global distribution of meteor radars

Xue

Murphy

et al. 2019

Atmos. Chem. Phys.

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Abstract. The existing distribution of meteor radars located from high- to low-latitude regions provides a favorable temporal and spatial coverage for investigating the climatology of the global mesopause density. In this study, we report the climatology of the mesopause relative density estimated using multiyear observations from nine meteor radars, namely, the Davis Station (68.6∘ S, 77.9∘ E), Svalbard (78.3∘ N, 16∘ E) and Tromsø (69.6∘ N, 19.2∘ E) meteor radars located at high latitudes; the Mohe (53.5∘ N, 122.3∘ E), Beijing (40.3∘ N, 116.2∘ E), Mengcheng (33.4∘ N, 116.6∘ E) and Wuhan (30.5∘ N, 114.6∘ E) meteor radars located in the midlatitudes; and the Kunming (25.6∘ N, 103.8∘ E) and Darwin (12.3∘ S, 130.8∘ E) meteor radars located at low latitudes. The daily mean relative density was estimated using ambipolar diffusion coefficients derived from the meteor radars and temperatures from the Microwave Limb Sounder (MLS) on board the Aura satellite. The seasonal variations in the Davis Station meteor radar relative densities in the southern polar mesopause are mainly dominated by an annual oscillation (AO). The mesopause relative densities observed by the Svalbard and Tromsø meteor radars at high latitudes and the Mohe and Beijing meteor radars at high midlatitudes in the Northern Hemisphere show mainly an AO and a relatively weak semiannual oscillation (SAO). The mesopause relative densities observed by the Mengcheng and Wuhan meteor radars at lower midlatitudes and the Kunming and Darwin meteor radars at low latitudes show mainly an AO. The SAO is evident in the Northern Hemisphere, especially at high latitudes, and its largest amplitude, which is detected at the Tromsø meteor radar, is comparable to the AO amplitudes. These observations indicate that the mesopause relative densities over the southern and northern high latitudes exhibit a clear seasonal asymmetry. The maxima of the yearly variations in the mesopause relative densities display a clear latitudinal variation across the spring equinox as the latitude decreases; these latitudinal variation characteristics may be related to latitudinal changes influenced by gravity wave forcing. In addition to an AO, the mesopause relative densities over low latitudes also clearly show an intraseasonal variation with a periodicity of 30–60 d.

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Section: Introductionmentioning

confidence: 99%

Climatology of the mesopause relative density using a global distribution of meteor radars

Xue

Murphy

et al. 2019

Atmos. Chem. Phys.

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“…The u w term appears to be anticorrelated with the zonal wind between 80 and 84 km around the winter solstice, as does v w with the meridional wind above 88 km across a similar time interval. While pronounced levels of anticorrelation between these quantities in the mesospheric region arising from the selective filtering mechanism are typical (see e.g., the recent summary provided by Jia et al (2018))-particularly in the zonal component-departures from these predictions are also not uncommon. As Jia et al (2018) explains, it is difficult to conceive a mechanism for departures from this theory in the zonal component (given the dominance of eastward winds in the lower mesosphere during winter), aside from considering that the GWs may have propagated from a region with weak eastward mesospheric winds.…”

Section: Covariances During the Austral Wintermentioning

confidence: 94%

Multistatic meteor radar observations of gravity wave-tidal interaction over Southern Australia

Spargo¹,

MacKinnon²

2019

Preprint

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This paper assesses the ability of a recently-installed 55 MHz multistatic meteor radar to measure gravity wave-driven momentum fluxes around the mesopause, and applies it in a case study of measuring gravity wave forcing on the diurnal tide during a period following the autumnal equinox of 2018. The radar considered is in the vicinity of Adelaide, South Australia (34.9 • S, 138.6 • E) and consists of a monostatic radar and bistatic receiver separated by approximately 55 km. 5The assessment shows that the inclusion of the bistatic receiver reduces the relative uncertainty of the momentum flux estimate from about 75% to 65% (for a flux magnitude of ∼ 20 m 2 s −2 , one day's worth of integration, and for a gravity wave field synthesized from a realistic spectral model). This increase in precision appears to be entirely attributable to the increased number of meteor detections associated with the combined monostatic and bistatic receivers, rather than changes in the meteors' spatial distribution. 10The case study reveals large modulations in the diurnal tidal amplitudes, with a maximum tidal amplitude of ∼ 50 ms −1 and an associated maximum zonal wind velocity of around 140 ms −1 . While the observed gravity wave forcing exhibits a complex relationship with the tidal winds during this period, the components of the forcing are seen to be approximately out of phase with the tidal winds above 88 km. No clear phase relationship has been observed below 88 km.

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“…Quality-control pre-processing was applied, as meteors located at smaller zenith angles typically produce larger horizontal velocity calculation errors, while meteors located at larger zenith angles often cause larger height measurement errors. As such, only meteor trails with zenith angles between 15 • and 60 • were included in the study [20]. In addition, meteors with radial velocities of more than 200 m/s often contain rapidly decaying fragments and were therefore discarded [13].…”

Section: Momentum Flux Determinationmentioning

confidence: 99%

“…Satellites can be used to indirectly estimate global GW momentum flux using measured temperature profiles [4]. Ground-based observation techniques, such as medium frequency radar [5], airglow imaging [6,7], laser radar [8,9], and meteor radar [10][11][12][13][14][15][16][17][18][19][20][21] have been used to estimate GW momentum flux at single sites. Airglow imagers measure the momentum flux of a single GW event, rather than the average of many waves.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal Variations of High-Frequency Gravity Wave Momentum Fluxes and Their Forcing toward Zonal Winds in the Mesosphere and Lower Thermosphere over Langfang, China (39.4° N, 116.7° E)

Tian

Liu

et al. 2020

Atmosphere

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Meteor radar data collected over Langfang, China (39.4° N, 116.7° E) were used to estimate the momentum flux of short-period (less than 2 h) gravity waves (GWs) in the mesosphere and lower thermosphere (MLT), using the Hocking (2005) analysis technique. Seasonal variations in GW momentum flux exhibited annual oscillation (AO), semiannual oscillation (SAO), and quasi-4-month oscillation. Quantitative estimations of GW forcing toward the mean zonal flow were provided using the determined GW momentum flux. The mean flow acceleration estimated from the divergence of this flux was compared with the observed acceleration of zonal winds displaying SAO and quasi-4-month oscillations. These comparisons were used to analyze the contribution of zonal momentum fluxes of SAO and quasi-4-month oscillations to zonal winds. The estimated acceleration from high-frequency GWs was in the same direction as the observed acceleration of zonal winds for quasi-4-month oscillation winds, with GWs contributing more than 69%. The estimated acceleration due to Coriolis forces to the zonal wind was studied; the findings were opposite to the estimated acceleration of high-frequency GWs for quasi-4-month oscillation winds. The significance of this study lies in estimating and quantifying the contribution of the GW momentum fluxes to zonal winds with quasi-4-month periods over mid-latitude regions for the first time.

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Multiyear Observations of Gravity Wave Momentum Fluxes in the Midlatitude Mesosphere and Lower Thermosphere Region by Meteor Radar

Cited by 20 publications

References 53 publications

Climatology of the mesopause relative density using a global distribution of meteor radars

Climatology of the mesopause relative density using a global distribution of meteor radars

Multistatic meteor radar observations of gravity wave-tidal interaction over Southern Australia

Seasonal Variations of High-Frequency Gravity Wave Momentum Fluxes and Their Forcing toward Zonal Winds in the Mesosphere and Lower Thermosphere over Langfang, China (39.4° N, 116.7° E)

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