Orographic effects related to deep convection events over the Andes region
Orographic effects related to deep convection events over the Andes region
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DOI：
10.1016/j.atmosres.2012.08.020
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发表时间：
2013-02
影响因子：
5.5
通讯作者：
R. Hierro;H. Pessano;P. Llamedo;A. Torre;P. Alexander;A. Odiard
中科院分区：
文献类型：
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作者：
R. Hierro;H. Pessano;P. Llamedo;A. Torre;P. Alexander;A. Odiard
在这项工作中，我们分析了 2006 年至 2011 年间在阿根廷门多萨南部发生的 39 场风暴。这是一个位于中纬度地区（大约在南纬32度到36度之间）的半干旱地区，位于安第斯山脉最高峰以东，构成了一个天然实验室，通常会发生多种重力波源。我们考虑圣拉斐尔区附近的一个耕地分区，每年夏天都会记录系统性的深对流事件。我们建议将包裹提升到自由对流水平所需的升力机制部分由山波（MW）提供。根据天气研究和预报（WRF）中尺度模型模拟和雷达网络数据，我们计算了每次风暴发展过程中对流可用势能和对流抑制指数的演变。全局最终分析用于构造初始条件和边界条件。对流抑制指数与MW能够提供的垂直动能进行比较，以便粗略估计这种可能的触发机制。选择垂直速度作为适当的动态变量，以证明在每个检测到的第一雷达回波附近存在微波。在根据之前的工作建立了代表兆瓦的标准后，39 个风暴被分为两个子集：存在兆瓦和不存在兆瓦。保留并考虑 12 个具有相当大 MW 幅度的案例。分析了两个样本之间的雷达数据差异，并对模拟的微波进行了表征。
In this work, we analyze a set of 39 storms which took place between 2006 and 2011 over the South of Mendoza, Argentina. This is a semiarid region situated at mid-latitudes (roughly between 32S and 36S) at the east of the highest Andes tops which constitutes a natural laboratory where diverse sources of gravity waves usually take place. We consider a cultivated subregion near San Rafael district, where every summer a systematic generation of deep convection events is registered. We propose that the lift mechanism required to raise a parcel to its level of free convection is partially supplied by mountain waves (MWs). From Weather Research and Forecasting (WRF) mesoscale model simulations and radar network data, we calculate the evolution of convective available potential energy and convective inhibition indices during the development of each storm. Global Final Analysis is used to construct initial and boundary conditions. Convective inhibition indices are compared with the vertical kinetic energy capable of being supplied by the MWs, in order to provide a rough estimation of this possible triggering mechanism. Vertical velocity is chosen as an appropriate dynamical variable to evidence the presence of MWs in the vicinity of each detected first radar echo. After establishing a criterion based on a previous work to represent MWs, the 39 storms are split into two subsets: with and without the presence of MWs. 12 cases with considerable MWs amplitude are retained and considered. Radar data differences between the two samples are analyzed and the simulated MWs are characterized.