Symmetric inner and outer dynamics of Super Typhoon Lekima (2019) during its size expansion

In this work, simulation data of Super typhoon Lekima (2019) produced by the Weather Research and Forecasting model are analyzed to study its symmetric inner and outer dynamics during its size expansion. The analysis includes the calculation of the symmetric rotational kinetic energy budget in the cylindrical coordinates and the separation of dominant budget terms. In the outer area, the conversion from symmetric divergent kinetic energy through the advection of symmetric divergent flow by symmetric rotational flow was the primary process for enhancing symmetric rotational kinetic energy. The conversion from environmental kinetic energy due to the advection of environmental flow by symmetric typhoon flow was secondary. In the inner area, frictional dissipation was the primary factor responsible for reducing the symmetric rotational kinetic energy. The flux divergence of symmetric rotational kinetic energy by symmetric divergent circulation was secondary. 摘要. 本文利用高分辨率WRF模式模拟数据, 分析了超强台风“利奇马”(2019)在快速增强期间的对称性内外圈动力学差异.通过在柱坐标中计算并分解对称旋转动能(Kψs)收支, 揭示了主要能量转换过程.结果表明, 外圈Kψs的增加主要来自对称旋转运动平流引起的对称辐散动能向外圈Kψs的能量转换, 其次为同样是对称旋转运动平流引起的环境动能的转换贡献;而内圈Kψs的减少由摩擦耗散(主要)和对称辐散流引起的对称旋转动能水平通量散度变化(次要)造成.