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- Title
Sources of Concentric Gravity Waves Generated by a Moving Mesoscale Convective System in Southern Brazil.
- Authors
Nyassor, Prosper Kwamla; Wrasse, Cristiano Max; Paulino, Igo; São Sabbas, Eliah F. M. T.; Valentine Bageston, José; Pinheiro Naccarato, Kleber; Gobbi, Delano; Oliveira Barros Figueiredo, Cosme Alexandre; Ayorinde, Toyese Tunde; Hisao Takahashi; Barros, Diego
- Abstract
The studies on the sources of three concentric gravity waves (CGWs) excited by a moving Mesoscale Convective System (MCS) on the night of October 1 - 2, 2019 are investigated. These CGWs were observed using an OH all-sky imager whereas the MCS were observed by the Geostationary Operational Environmental Satellite (GOES). Using 2D spectral analysis, we observed that the CGWs have horizontal wavelength λH ~30 - 55 km, phase speed cH ~70 - 90 m/s, and period τ ~7 - 12 min. By backward ray tracing we found that two of the waves were excited from convective cores within the MCS. We also found that the epicenters of the CGWs were close to the tropopause positions of the ray traced paths as well as the nearby convective cores. Regarding the source, we verified that on this night the cold-point tropopause (CPT) was -80°C, which was 10C cooler than CPT on the days preceding and after the MCS, and also colder than usually observed. Since the tropopause height and temperature are fundamental parameters underlying the analysis of the overshooting extent, we developed our own methodology to establish a reference tropopause that would enable a quantitative estimate of this parameter. Since the MCS (CGWs source) was moving, the overshooting convective cores were tracked in space and time. Finally, we found that two out of the three CGWs were excited by the MCS whereas the source of the remaining one was found not to be directly associated with the MCS.
- Subjects
BRAZIL; MESOSCALE convective complexes; GOES (Meteorological satellite); GRAVITY waves; RAY tracing; TROPOPAUSE
- Publication
Atmospheric Chemistry & Physics Discussions, 2022, p1
- ISSN
1680-7367
- Publication type
Article
- DOI
10.5194/acp-2022-267