Inertial Waves in Axisymmetric Tropical Cyclones
Inertial Waves in Axisymmetric Tropical Cyclones
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轴对称热带气旋中的惯性波
DOI：
10.1175/jas-d-19-0330.1
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
D. Chavas
中科院分区：
文献类型：
--
作者：
Morgan E. O'Neill;D. Chavas
热带气旋的热机模式描述了一个热直接翻转环流。随着向太空的辐射冷却平衡绝热变暖，流出的空气慢慢减弱，这一过程不消耗任何功。然而，我们在这里表明，流出物的横向扩散受到环境变形半径的限制，而环境变形半径在高纬度地区可能相当小。在这种情况下，流出的空气受到径向约束，这限制了它仅通过辐射冷却向下沉降的程度。一些文献援引了在高惯性稳定性存在的风暴流出区“机械沉降”或“强迫下降”的可能性，这将是一个热间接环流。热带气旋沉降分支的机械沉降以前没有被观察到或描述过。通过对不同纬度和不同面积的轴对称热带气旋进行模拟，研究了环境惯性稳定性对风暴动力学的影响。在大轴对称区域的高纬度风暴中，流出体充当了一个造波器，以环境惯性（科里奥利）频率激发惯性波。这种惯性波周期性地用它自己的低熵废气给高纬度风暴的核心通风。波浪响应与假定的强迫下降模型相反，我们假设这是因为惯性稳定性比浮力稳定性提供更小的阻力，即使在高度惯性稳定的环境中也是如此。
The heat engine model of tropical cyclones describes a thermally direct overturning circulation. Outflowing air slowly subsides as radiative cooling to space balances adiabatic warming, a process that does not consume any work. However, we show here that the lateral spread of the outflow is limited by the environmental deformation radius, which at high latitudes can be rather small. In such cases, the outflowing air is radially constrained, which limits how far downward it can subside via radiative cooling alone. Some literature has invoked the possibility of `mechanical subsidence' or `forced descent' in the storm outflow region in the presence of high inertial stability, which would be a thermally indirect circulation. Mechanical subsidence in the subsiding branch of a tropical cyclone has not before been observed or characterized. A series of axisymmetric tropical cyclone simulations at different latitudes and domain sizes is conducted to study the impact of environmental inertial stability on storm dynamics. In higher latitude storms in large axisymmetric domains, the outflow acts as a wavemaker to excite an inertial wave at the environmental inertial (Coriolis) frequency. This inertial wave periodically ventilates the core of a high-latitude storm with its own low entropy exhaust air. The wave response is in contrast to the presumed forced descent model, and we hypothesize that this is because inertial stability provides less resistance than buoyant stability, even in highly inertially stable environments.
飓风高分辨率模拟中热力学循环的重建
影响因子：
3.1
作者：
Pauluis, Olivier M.;Zhang, Fuqing
通讯作者：
Zhang, Fuqing