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Three-dimensional potential vorticity structures for extreme precipitation events on the convective scale
Tellus A: Dynamic Meteorology and Oceanography ( IF 1.7 ) Pub Date : 2020-01-01 , DOI: 10.1080/16000870.2020.1811535
Annette Müller 1 , Benjamin Niedrich 1 , Peter Névir 1
Affiliation  

Abstract Three-dimensional potential vorticity (PV) structures on the convective scale during extreme precipitation events are investigated. Using the high resolution COSMO-REA2 data set, 3D composites of the PV, with and without Coriolis parameter and related variables, are evaluated for different classes of precipitation intensity. The development of a significant horizontal dipole structure in the immediate vicinity of the precipitation maximum and the updraft can be explained by the twisting term in the vorticity equation. This is because the vorticity equation is proportional to the PV equation for strong convective processes. This theoretical is important on the convective scale without the consideration of the Coriolis effect, which is a typical characteristic on the synoptic scale. In accordance to previous studies, the horizontal PV dipole is statistically confirmed by 3D composites of the PV and corresponding variables. We show that the dipole structures are especially distinct for the relative PV without Coriolis parameter and the relative vorticity. On the convective scale, the thermodynamical sources and sinks of the potential vorticity indicate the diabatic processes that are related to conservative vortex dynamics via the proportionality of the diabatic heating and the vertical velocity. This work confirms that the PV equation is an important tool in atmospheric dynamics that unifies the thermodynamical processes as well as the dynamical processes into one scalar.

中文翻译:

对流尺度极端降水事件的三维位涡结构

摘要 研究了极端降水事件期间对流尺度上的三维位涡(PV)结构。使用高分辨率 COSMO-REA2 数据集,PV 的 3D 复合材料(带有和不带有科里奥利参数和相关变量)针对不同类别的降水强度进行评估。在降水最大值和上升气流附近形成显着的水平偶极子结构可以用涡量方程中的扭曲项来解释。这是因为涡度方程与强对流过程的 PV 方程成正比。这个理论在对流尺度上很重要,而没有考虑科里奥利效应,这是天气尺度上的典型特征。根据以往的研究,水平 PV 偶极子通过 PV 和相应变量的 3D 合成在统计上得到证实。我们表明,偶极子结构对于没有科里奥利参数和相对涡度的相对 PV 来说尤其明显。在对流尺度上,位涡的热力学源和汇通过非绝热加热和垂直速度的比例指示与保守涡动力学相关的非绝热过程。这项工作证实了 PV 方程是大气动力学中的一个重要工具,它将热力学过程和动力学过程统一为一个标量。我们表明,偶极子结构对于没有科里奥利参数和相对涡度的相对 PV 来说尤其明显。在对流尺度上,位涡的热力学源和汇通过非绝热加热和垂直速度的比例指示与保守涡动力学相关的非绝热过程。这项工作证实了 PV 方程是大气动力学中的一个重要工具,它将热力学过程和动力学过程统一为一个标量。我们表明,偶极子结构对于没有科里奥利参数和相对涡度的相对 PV 来说尤其明显。在对流尺度上,位涡的热力学源和汇通过非绝热加热和垂直速度的比例指示与保守涡动力学相关的非绝热过程。这项工作证实了 PV 方程是大气动力学中的一个重要工具,它将热力学过程和动力学过程统一为一个标量。
更新日期:2020-01-01
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