Nocturnal boundary layer turbulence regimes analysis during the BLLAST campaign
Nocturnal boundary layer turbulence regimes analysis during the BLLAST campaign
复制标题
BLLAST 活动期间的夜间边界层湍流状况分析
DOI：
10.5194/acp-19-9495-2019
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发表时间：
2019
影响因子：
6.3
通讯作者：
Jielun Sun
中科院分区：
文献类型：
--
作者：
Jesús Yus;M. Udina;M. R. Soler;M. Lothon;E. Nilsson;J. Bech;Jielun Sun
抽象。利用2011年夏季在法国比利牛斯山麓中部进行的边界层午后和日落湍流（BLLAST）野外活动的数据，对Sun等人（2012）在1999年合作大气-地面交换研究（CASES-99）中提出的夜间湍流状态分类，即所谓的“霍克-棍子转换“（HOST）理论进行了探讨。结果表明，对于BLLAST现场活动数据的HOST湍流关系强烈地依赖于气象和地形特征。主机模式只出现在晚上，当一个稳定的分层边界层可以发展，对应于晴朗的天气和晴朗的天空的夜晚，当流动是由附近的地形，从南部和东南部。受地形强烈影响的气流可能产生间歇性或增强的湍流。当考虑这些流向的整个夜间数据集时，发现几个增强的湍流点与突然的风速和方向性切变转变有关。相反，从其他方向的流动不再现主机关系和湍流关系几乎是线性的，独立于垂直温度梯度，对应于天气尺度驱动的流动。此外，我们确定的重力波和自上而下的湍流事件，导致湍流制度之间的过渡的例子。
Abstract. A night-time turbulence regime classification, the so-called “HOckey-Stick Transition ” (HOST) theory, proposed by Sun et al. (2012) from the Cooperative Atmosphere–Surface Exchange Study-1999 (CASES-99) is explored using data from the Boundary-Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign which took place during summer 2011 in the central French Pyrenean foothills. Results show that the HOST turbulence relationships for the BLLAST field campaign data are strongly dependent on both the meteorological and orographic features. The HOST pattern only appears for nights when a stably stratified boundary layer can be developed, corresponding to fair-weather and clear-sky nights, when the flow is generated by the nearby orography, from the south and the south-east. Those flows strongly influenced by the orography may generate intermittent or enhanced turbulence. When considering the whole nocturnal dataset for these flow directions, several enhanced turbulence points are found to be associated with sudden wind speed and directional shear transitions. In contrast, flows from other directions do not reproduce the HOST relationships and the turbulence relationship is almost linear, independent of vertical temperature gradients, corresponding to flows driven by synoptic scales. In addition we identify examples of gravity waves and top-down turbulent events that lead to transitions between the turbulence regimes.
影响因子：
6.3
作者：
Andreae, M. O.;Acevedo, O. C.;Yanez-Serrano, A. M.
通讯作者：
Yanez-Serrano, A. M.