On the Lateral Entrainment Instability in the Inner Core Region of Tropical Cyclones
On the Lateral Entrainment Instability in the Inner Core Region of Tropical Cyclones
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DOI：
10.1029/2022gl102494
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发表时间：
2023-04
影响因子：
5.2
通讯作者：
Ping Zhu;Jun A. Zhang;F. Marks
中科院分区：
文献类型：
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作者：
Ping Zhu;Jun A. Zhang;F. Marks
具有低等效位温的干燥护城河空气横向夹带进入眼墙和雨带是热带气旋（TC）内核区域的独特湍流过程。通过分析穿越飓风丽塔（2005年）、帕特里夏（2015年）、哈维（2017年）和迈克尔（2018年）飓风眼墙和雨带的侦察飞行收集的现场飞机测量数据，以及飓风帕特里夏（2015年）和迈克尔（2018年）的数值模拟，我们表明护城河空气夹带到眼墙和雨带满足不稳定标准，因此作为对流下沉气流不稳定下沉。由此产生的正浮力通量是眼墙和雨带云中湍流动能（TKE）的重要来源。这种通过横向夹带不稳定性产生 TKE 的机制应包含在 TKE 型湍流混合方案中，以便在 TC 数值预报中更好地表示湍流传输过程。
Entrainment of dry moat air with low equivalent potential temperature laterally into the eyewall and rainbands is a unique turbulent process in the inner‐core region of a tropical cyclone (TC). By analyzing in‐situ aircraft measurements collected by the reconnaissance flights that penetrated the eyewalls and rainbands of Hurricanes Rita (2005), Patricia (2015), Harvey (2017), and Michael (2018), as well as numerical simulations of Hurricanes Patricia (2015), and Michael (2018), we show that the moat air entrained into the eyewall and rainbands meets the instability criterion, and therefore, sinks unstably as a convective downdraft. The resultant positive buoyancy fluxes are an important source for the turbulent kinetic energy (TKE) in the eyewall and rainband clouds. This mechanism of TKE generation via lateral entrainment instability should be included in the TKE‐type turbulent mixing schemes for a better representation of turbulent transport processes in numerical forecasts of TCs.