Navegando por Assunto "Gravity waves"

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    Momentum flux characteristics of vertically propagating gravity waves
    (European Geosciences Union) Nyassor, Prosper Kwamla; Wrasse, Cristiano Max; Paulino, Igo; Yigit, Erdal; Tsali-Brown, Vera Yesutor; Buriti, Ricardo Arlen; Figueiredo, Cosme Alexandre Oliveira Barros; Giongo, Gabriel Augusto; Egito, Fabio; Adebayo, Oluwasegun Micheal; Takahashi, Hisao; Gobbi, Delano
    Momentum flux and propagation dynamics of two vertically propagating atmospheric gravity waves (GWs) are studied using observations at São João do Cariri (7.40° S, 36.31° W), Brazil, from co-located pho- tometer, all-sky imager, and meteor radar instruments. Time series of the atomic oxygen green line (OI 557.7 nm), molecular oxygen (O2 (0–1)), sodium D-line (NaD), and hydroxyl (OH (6–2)) airglow intensity variations mea- sured by the photometer were used to investigate the vertical characteristics and vertical phase progression of the GWs with similar (± 10 % of the error margin) or nearly the same (± 5 % of the error margin) period across these emission layers. The horizontal parameters of the same GWs were determined from the OH airglow im- ages, whereas the intrinsic parameters of the horizontal and vertical components of the GWs were estimated with the aid of the observed winds. Using the phase of the GWs at each emission layer, the characteristics of the phase progression exhibited near-vertical propagation under a duct background propagation condition. This indicates that the duct contributes significantly to the observed near-vertical phase propagation. The GW mo- mentum flux and potential energy were estimated using the rotational temperatures of OH and O2, revealing that the time series of momentum fluxes and potential energies are higher in the O2 emission band than in the OH band, indicating a transfer of momentum and energy across OH to the O2 altitude. These results reveal the effect of a duct on vertically propagating GWs and the associated momentum flux and potential energy transfer from the lower to the upper altitudes in the mesosphere.