违反了 PRIMARY KEY 约束 'PK_t_counter'。不能在对象 'dbo.t_counter' 中插入重复键。 语句已终止。 大气边界层阵风相干结构的产生条件-Conditions for the Formation of the Coherent Structure in Gusty Disturbances in the Atmospheric Boundary Layer
doi:  10.3878/j.issn.1006-9585.2016.16063
大气边界层阵风相干结构的产生条件

Conditions for the Formation of the Coherent Structure in Gusty Disturbances in the Atmospheric Boundary Layer
摘要点击 228  全文点击 270  投稿时间:2016-03-25  
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基金:  国家自然科学基金项目40830103、41375018,国家重点基础研究发展计划(973计划)项目2010CB951804,中国科学院战略先导专项XDA10010403
中文关键词:  大气边界层  阵风  相干结构  稳定度  湍流
英文关键词:  Atmospheric boundary layer  Gusty wind  Coherent structure  Stability  Turbulence
        
作者中文名作者英文名单位
李奇龙LI Qilong中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029;中国科学院大学, 北京 100049
程雪玲CHENG Xueling中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室, 北京 100029
曾庆存ZENG Qingcun中国科学院大气物理研究所, 北京 100029
引用:李奇龙,程雪玲,曾庆存.2016.大气边界层阵风相干结构的产生条件[J].气候与环境研究,21(6):725-736,doi:10.3878/j.issn.1006-9585.2016.16063.
Citation:LI Qilong,CHENG Xueling,ZENG Qingcun.2016.Conditions for the Formation of the Coherent Structure in Gusty Disturbances in the Atmospheric Boundary Layer[J].Climatic and Environmental Research(in Chinese),21(6):725-736,doi:10.3878/j.issn.1006-9585.2016.16063.
中文摘要:
      壁湍流相干结构的发现是近代湍流研究的重大进展之一,从20世纪50年代开始,在大气边界层湍流中也发现了相干结构——对流云街,并进行了系统的研究。近些年来,人们发现在近地层湍流中也存在相干结构。利用北京325 m气象塔对城市下垫面中大风和小风天气的风速分析,发现较有规律的周期3~6 min的阵风,且有明显的相干结构,而对不同下垫面的阵风研究,均发现存在这种相干结构,这种阵风相干结构对通量输送有不可忽视的作用。本文利用2012年4月甘肃省民勤县巴丹吉林沙漠观测塔的超声风速和平均场风速、温度观测资料,对阵风相干结构的产生条件进行了分析。采用傅立叶变换,将三维超声风速按频率分成基流(周期10分钟以上)、阵风扰动(周期1到10分钟)、湍流脉动(周期小于1分钟)三部分,结合平均场的资料分析发现:阵风相干结构出现在静力中性、不稳定甚至略微稳定的条件下,或者说机械作用主导的大气边界层,阵风区就会出现相干结构,热力作用对其有抑制和干扰的作用。从而,阵风的相干结构和壁面相干结构都出现在中性条件下,是机械湍流的现象,都主导着动量能量的输运。阵风区的相干结构并不等同于对流云街,他们出现在不同的大气稳定度条件下且尺度不同。
Abstract:
      The discovery of coherent structures in wall turbulence is one of the significant progresses in modern research of turbulence. The coherent structure was found in the atmospheric boundary layer in the 1950s, which was called cloud street and has been studied extensively. In recent years, a coherent structure was also found in the surface layer. Based on analysis of strong wind and light wind data in the urban boundary layer collected at the 325 m meteorological tower in Beijing, it is revealed that gusty disturbances have a period equal to around 3-6 min and possess coherent structure. The coherent structure is also found in disturbances over different underlying surfaces and makes downward transport of momentum more effectively. Conditions for the formation of the coherent structure in gusty disturbances was investigated using the turbulent data from the ultrasonic anemometer-thermometers and the mean wind and temperature data collected at the monitoring tower in the Badan Jilin Desert in Minqin County of Gansu Province in April 2012. The time series of three dimensional atmospheric velocity were analyzed using conventional Fourier spectral analysis. The atmospheric velocity was decomposed into three components:basic mean flow (period>10 min.), gusty disturbance (1 min < period < 10 min.) and turbulence fluctuation (period<1 min.). The results show that the coherent structure occurs in neutral, unstable and even slightly stable boundary layer. In other words, the coherent structure occurs under the condition that the turbulence is mainly generated by mechanical action, and it can be suppressed or disturbed by buoyancy. Thus, the coherent structure in the gusty wind and that in wall turbulence occur in neutral boundary layer. It is generated by mechanical action and plays a major role in energy and momentum transport. The coherent structure in the gusty wind is not the same as cloud street, and it appears under different atmospheric stability conditions and has different scales.
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