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杜群, 洪钟祥, 刘翔卿. 北京冬季大风过程大气边界层特征分析[J]. 气候与环境研究, 2017, 22(2): 212-220. DOI: 10.3878/j.issn.1006-9585.2016.16086
引用本文: 杜群, 洪钟祥, 刘翔卿. 北京冬季大风过程大气边界层特征分析[J]. 气候与环境研究, 2017, 22(2): 212-220. DOI: 10.3878/j.issn.1006-9585.2016.16086
Qun DU, Zhongxiang HONG, Xiangqing LIU. Analysis of Atmospheric Boundary Layer Characteristics during Strong Winter Wind Processes in Beijing[J]. Climatic and Environmental Research, 2017, 22(2): 212-220. DOI: 10.3878/j.issn.1006-9585.2016.16086
Citation: Qun DU, Zhongxiang HONG, Xiangqing LIU. Analysis of Atmospheric Boundary Layer Characteristics during Strong Winter Wind Processes in Beijing[J]. Climatic and Environmental Research, 2017, 22(2): 212-220. DOI: 10.3878/j.issn.1006-9585.2016.16086

北京冬季大风过程大气边界层特征分析

Analysis of Atmospheric Boundary Layer Characteristics during Strong Winter Wind Processes in Beijing

  • 摘要: 利用北京中国科学院大气物理研究所325 m气象观测塔的气象梯度资料和湍流资料,分析了2014年11月29日至12月5日北京两次大风过程中气象要素和湍流输送特征的变化。第一次大风过程的强度和持续时间均高于第二次大风过程。强烈的风速垂直切变主要集中在距地面100 m高度范围内,最强风速垂直切变达到0.31 s-1。大风过程中,阵风系数呈现随高度减小的趋势,越接近地面,阵风系数愈大。阵风强度的变化与阵风系数相似,100 m以下高度时,阵风强度随高度增大而减小。大风过程自上而下改变边界层结构,平均动能、湍流动能和摩擦速度最先从上层(280 m)发生变化且迅速增加。近地层由于风速垂直梯度的显著差异,近地层垂直方向的湍流强度最大。大风时各功率谱在低频区( < 0.01 s-1)达到峰值,大风过后各高度的能量都有所下降。

     

    Abstract: Based on meteorological gradient data and turbulent data from the 325-m observation tower of Institute of Atmospheric Physics, Chinese Academy of Sciences in Beijing, the meteorological condition and turbulent transfer characteristic were analyzed during two strong wind events occurred from 29 November to 5 December 2014. The magnitude and duration of the first strong wind event was larger than that of the second one. Strong vertical wind shear was found at the height below 100 meters above the ground surface, with the maximum value of 0.31 s-1. The gust coefficient decreased with height, and a higher value of gust coefficient was found near the surface layer. The variation of gust intensity was similar to that of gust coefficient, and it also decreased with height below 100 meters. The turbulent structure was changed by the strong wind from the top to bottom. The average kinetic energy, turbulent kinetic energy and friction velocity all started to change from the top layer (280 m) and then increased rapidly. As a result of the remarkable difference in vertical wind gradient near the surface layer, the maximum turbulent intensity in the vertical direction occurred near the surface layer. The power spectra of all layers were higher in low frequency areas ( < 0.01 s-1) during the strong wind event, and the power of all layers decreased after the strong wind event.

     

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