The structure of tornadoes near Attica, Kansas, on 12 May 2004: High-resolution, mobile, Doppler radar observations
The structure of tornadoes near Attica, Kansas, on 12 May 2004: High-resolution, mobile, Doppler radar observations
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DOI：
10.1175/mwr3295.1
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发表时间：
2007-02-01
影响因子：
3.2
通讯作者：
Pazmany, Andrew L.
中科院分区：
文献类型：
--
作者：
Bluestein, Howard B.;Weiss, Christopher C.;Pazmany, Andrew L.
2004年5月12日，马萨诸塞州大学的W波段和X波段移动的多普勒雷达近距离扫描了堪萨斯中南部的几个龙卷风。详细的垂直结构的多普勒风场和雷达反射率场的龙卷风之一的描述与援助的boresighted视频。龙卷风内部的一个弱回声空洞内壁，在距离地面数十米的范围内，以碗状边界的形式终止于底部。在龙卷风最低500米处的沿着一个边缘观察到水平涡旋的多普勒特征。多普勒速度的垂直结构在100米尺度上表现出显著的变化。在龙卷风的中心附近，一个近似水平的、辐射状的弱回波空洞的凸起在近似500 - 600米的AGL下降到离地面约400米的地方，在龙卷风的南部明显地形成了一个弱回波带。有人建议，这一功能代表回波弱的物质输送径向向外的垂直环流。在龙卷核心内外的表面摩擦层中，都发现了多普勒速度的显著垂直变化。一个弱的回波缺口，这是与钩状回波缠绕在龙卷风的形状进行了描述。最高的多普勒速度位于冷凝漏斗的外部。其他龙卷风的结构也有描述，但细节要少得多。一些分析进行了比较，与其他地方做的数值模拟龙卷风样的漩涡。
The University of Massachusetts W- and X-band, mobile, Doppler radars scanned several tornadoes at close range in south-central Kansas on 12 May 2004. The detailed vertical structure of the Doppler wind and radar reflectivity fields of one of the tornadoes is described with the aid of boresighted video. The inside wall of a weak-echo hole inside the tornado was terminated at the bottom as a bowl-shaped boundary within several tens of meters of the ground. Doppler signatures of horizontal vortices were noted along one edge in the lowest 500 m of the tornado. The vertical structure of Doppler velocity displayed significant variations on the 100-m scale. Near the center of the tornado, a quasi-horizontal, radial bulge of the weak-echo hole at similar to 500 - 600 m AGL dropped to about 400 m above the ground and was evident as a weak-echo band to the south of the tornado. It is suggested that this feature represents echo-weak material transported radially outward by a vertical circulation. Significant vertical variations of Doppler velocity were found in the surface friction layer both inside and outside the tornado core. The shape of a weak-echo notch that was associated with a hook echo wrapped around the tornado is described. Highest Doppler velocities were located outside the condensation funnel. The structure of the other tornadoes is also described, but with much less detail. Some of the analyses are compared with numerical simulations of tornado-like vortices done elsewhere.