Kinematic Observations of Misocyclones along Boundaries during IHOP
Kinematic Observations of Misocyclones along Boundaries during IHOP
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DOI：
10.1175/mwr3367.1
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发表时间：
2007-05
影响因子：
3.2
通讯作者：
James N. Marquis;Yvette P. Richardson;J. Wurman
中科院分区：
文献类型：
--
作者：
James N. Marquis;Yvette P. Richardson;J. Wurman
在国际水项目期间，移动雷达收集了沿至少五个中尺度气团边界的几个0.5-2千米宽的垂直定向涡旋(或米斯气旋)的高分辨率数据。这项研究分析了其中三个数据集--2002年6月3日、10日和19日--的米斯气旋的性质，以验证FineScale数值模式的发现和过去对米斯气旋的其他观测结果，并进一步了解它们在启动深层湿对流和非超级单体龙卷风中所起的作用。气旋使沿每个边界的低层辐合带发生不同程度的弯曲或分离，这取决于其环流的大小。当几个相对较大的米斯气旋相邻时，沿每个边界的低层辐合形状排列成阶梯状。米斯气旋的合并是涡量场演化中的一个重要过程，因为一群小涡旋合并成了较少数量的大涡旋。此外，当合并轴垂直于边界时，合并米斯气旋可能会影响其附近热力学场的混合。气旋与邻近每个边界的气团的行星边界层(PBL)中的线状和蜂窝结构相互作用。这两种结构产生的气旋性低层垂直涡度与每一边界接触，有时并入先前存在的米斯气旋。无论哪种类型的PBL结构与边界相交，都会产生更强的低层辐合区域，通常还会产生更强的米索气旋。
During the International H2O Project, mobile radars collected high-resolution data of several 0.5–2-kmwide vertically oriented vortices (or misocyclones) along at least five mesoscale airmass boundaries. This study analyzes the properties of the misocyclones in three of these datasets—3, 10, and 19 June 2002—to verify findings from finescale numerical models and other past observations of misocyclones and to further the understanding of the role that they play in the initiation of deep moist convection and nonsupercell tornadoes. Misocyclones inflect or disjoint the swath of low-level convergence along each boundary to varying degrees depending on the size of their circulations. When several relatively large misocyclones are next to each other, the shape of low-level convergence along each boundary is arranged into a staircase pattern. Mergers of misocyclones are an important process in the evolution of the vorticity field, as a population of small vortices consolidates into a smaller number of larger ones. Additionally, merging misocyclones may affect the mixing of thermodynamic fields in their vicinity when the merger axis is perpendicular to the boundary. Misocyclones interact with linear and cellular structures in the planetary boundary layers (PBLs) of the air masses adjacent to each boundary. Cyclonic low-level vertical vorticity generated by both types of structures makes contact with each boundary and sometimes is incorporated into preexisting misocyclones. Intersections of either type of PBL structure with the boundary result in strengthened pockets of low-level convergence and, typically, strengthened misocyclones.