热带气旋发展增强过程中龙卷尺度涡旋活动特征
周玥滢, 方娟

Characteristics of tornado⁃scale vortices in an intensifying tropical cyclone
Yueying Zhou, Juan Fang
图8 30日18时和31日06时1 km高度以下平均的(a, c)浮力振荡频率N2(单位:s-2)和(b, d)水平风垂直切变S2(单位:s-2),黑色圆环表示200 m高度上最大风速半径
Fig.8 (a, c) buoyancy oscillation frequencies N2 (unit: s-2) and (b, d) horizontal wind vertical shear S2 (unit: s-2) averaged below 1 km altitude at 18:00 on the 30th and 06:00 on the 31st,with the black circle indicating the radius of maximum wind speed at 200 m altitude