Cylindrical gravity waves generated by thunderstorm driven sources at tropospheric altitudes
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摘要: 已有充分的证据表明, 大气对流层的雷暴迹象是大气中间层重力波活动的显著代表源.在雷暴迹象的上方, 通过火箭已观测到大气中间层出现的热效应, 也已通过雷 达探测到大气平流层出现的上行重力波, 从地面和卫星平台上观察到夜间气辉有序而 成环状的重力波波形. 所有这些实验结果都与位于观测点下方的雷暴活动有紧密联系. 此类雷暴通常主要集中在中国东部沿海以及地球其他沿海海湾地域. 关于此类雷暴对大 气中间层的影响尚未被充分研究和了解. 为能有效地探究其成因, 利用所开发的一个二维计算机数值模型模拟和研究大气对流层的雷暴源所引发的上行重力波, 进而揭示 此类重力波产生的基本物理机理, 及其在大气中间层的能量耗散. 通过模拟研究发现, 雷暴源可以大面积高强度地聚集和释放积雨云的能量, 当这种周期性的对流变化引发大气对流层的不稳定性后, 就会有圆柱体重力波的产生和传播.Abstract: Solid evidences have shown tropospheric thunderstorms as representative sources of gravity wave activity at mesospheric altitudes. For instances, mesospheric heating was detected by rockets above thunderstorms. Upward traveling gravity waves were also observed by radar at stratospheric altitudes. Coherent circular gravity wave structure through nightglow emission exhibits from ground and satellite based platform observations. All these evidences are strongly associated with underlying thunderstorm activity. These types of storm occur frequently over the eastern coast of China, and over many other coast lines of the globe. Their mesospheric effects have not yet been adequately studied and described in scientific literature. With a numerical modeling, the paper focuses on a better understanding of the basic physics underlying the generation of such gravity waves and their energy dissipation at mesospheric altitudes. It shows that, during thunderstorm formation the cumulus can intensely and periodically absorb and release energy within large area, the instability of the troposphere occurs along with this periodical convection. Under such conditions, a simulated packet of the cylindrical gravity waves arises and propagates upward in our numerical model.
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Key words:
- Numerical modeling /
- Gravity waves /
- Convection /
- Thunderstorm /
- Dissipation
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