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 λ_H ∼30 – 55 km, phase speed c_H ∼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 ∼10 °C 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.

中文翻译：

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巴西南部移动中尺度对流系统产生的同心引力波源

摘要。对 2019 年 10 月 1 日至 2 日夜间移动的中尺度对流系统 (MCS) 激发的三个同心重力波 (CGW) 的来源进行了研究。这些 CGW 是使用 OH 全天成像仪观察到的，而 MCS 是由地球静止运行环境卫星 (GOES) 观察到的。使用二维光谱分析，我们观察到 CGW 的水平波长 λ _H ∼30 – 55 km，相速度c _H∼70 – 90 m/s, 周期 τ ∼7 – 12 min. 通过反向射线追踪，我们发现其中两个波是由 MCS 内的对流核心激发的。我们还发现 CGW 的震中靠近射线追踪路径的对流层顶位置以及附近的对流核心。关于来源，我们证实当晚冷点对流层顶（CPT）为~-80°C，比MCS前后几天的CPT低~10°C，也比通常观察到的更冷。由于对流层顶高度和温度是分析超调范围的基本参数，因此我们开发了自己的方法来建立参考对流层顶，从而能够对该参数进行定量估计。由于 MCS（CGWs 源）在移动，在空间和时间上跟踪过冲的对流核心。最后，我们发现三个 CGW 中有两个被 MCS 激发，而其余一个的源被发现与 MCS 没有直接关联。