Initiation Mechanisms of Nocturnal Convection without Nearby Surface Boundaries over the Central and Southern Great Plains during the Warm Season
Initiation Mechanisms of Nocturnal Convection without Nearby Surface Boundaries over the Central and Southern Great Plains during the Warm Season
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DOI：
10.1175/mwr-d-18-0040.1
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发表时间：
2018-08
影响因子：
3.2
通讯作者：
D. Reif;H. Bluestein
中科院分区：
文献类型：
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作者：
D. Reif;H. Bluestein
在过去的十年里，关于夜间对流的文献中的案例研究的数量有所增加，特别是那些利用来自国际H2O项目(IHOP_2002)和平原夜间高空对流(Peran)等野外实验的高时空分辨率数据集的案例研究。然而，很少有关于没有附近表面边界的对流引发事件的案例研究。这些事件约占夜间对流启动(CI)事件的25%。这些事件的独特特征包括：峰值启动时间在夜间较晚，在堪萨斯州北部和内布拉斯加州南部是首选的启动地点，以及线性对流系统的首选南北方向。在这项研究中，详细介绍了四个在没有附近地面边界的情况下启动对流的案例研究，以揭示一些可能的启动机制，包括准地转辅助上升、与(未知原因的)辐合层相关的上升、低层急流和重力波。所选的案例研究说明了发生这些事件的天气尺度条件多种多样。
The number of case studies in the literature of nocturnal convection has increased during the past decade, especially those that utilize high-spatiotemporal-resolution datasets from field experiments such as the International H2O Project (IHOP_2002) and Plains Elevated Convection at Night (PECAN). However, there are few case studies of events for convection initiation without a nearby surface boundary. These events account for approximately 25% of all nocturnal convection initiation (CI) events. Unique characteristics of these events include a peak initiation time later at night, a preferred initiation location in northern Kansas and southern Nebraska, and a preferred north–south orientation to linear convective systems. In this study, four case studies of convection that is initiated without a nearby surface boundary are detailed to reveal a number of possible initiation mechanisms, including quasigeostrophic-aided ascent, elevated ascent associated with convergent layers (of unknown causes), the low-level jet, and gravity waves. The case studies chosen illustrate the wide variety of synoptic-scale conditions under which these events can occur.