基于实测的北京城区2013-2015年间大气稳定度研究

发布时间：2018-06-05 07:37

本文选题：实测 + 风速　；参考：《北京交通大学》2017年硕士论文

【摘要】：随着超高层建筑、大跨度屋盖等风敏感结构的增多,关于结构风荷载特性及其风致效应的研究越来越重要,其中,大气边界层内风场特性是该类结构抗风性能研究的基础。大气稳定度、地貌类别是影响大气运动的最主要因素,由于城市热岛效应,使得大都市热对流、地表下垫面等大气条件与理想状态存在较大差异,确定大都市的风场特性,首先要对其大气稳定性进行研究。本文利用北京325m气象观测塔11台超声风速仪在2013—2015年间连续采集得到的风温数据,对北京城区大气稳定度的统计特征进行了研究,为进一步确定北京地区精细化风场模型奠定基础。所完成的主要工作如下:1)对北京城区风速、风向进行了统计分析。结果表明,北京城区风速和风向都呈现明显的季节特征,强风大多出现在春季与冬季;本文得到的北京城区主导风向为正北方向与NNE方向;北京城区地貌粗糙长度为1.03米,零平面位移为32.2米。2)选取了适用于北京城区的大气稳定度分类标准。对Richardson数与Monin-Obukhov(M-O)长度两类大气稳定度评价参数进行了对比分析,在此基础上,选定以M-O长度为评价参数,W.R.Wood的标准作为北京城区大气稳定度的分类标准。3)对北京城区大气稳定度进行统计分析。小风速区间内样本无论时间还是空间变化规律都不大,大风速区间样本变化明显。中性层结在春天与冬天时所占的比例相对比较大,夏天中性大气一年四季最少,不稳定大气最多。白天和晚上分别倾向于不稳定和稳定状态。随高度增加稳定大气频率增长明显较高高度处夏季尤为明显,冬季中性大气频率随高度有明显减少趋势。
[Abstract]:With the increase of wind sensitive structures such as long-span roofs in super-tall buildings, the study of wind load characteristics and wind-induced effects of structures is becoming more and more important. Among them, the wind field characteristics in the atmospheric boundary layer are the foundation of the study on the wind-resistant properties of such structures. Atmospheric stability and geomorphology are the most important factors affecting the atmospheric movement. Due to the urban heat island effect, the atmospheric conditions such as thermal convection and surface underlying surface are different from the ideal conditions, and the wind field characteristics of the metropolis are determined. First of all, the stability of its atmosphere should be studied. In this paper, the statistical characteristics of atmospheric stability in Beijing urban area are studied by using the wind temperature data collected continuously from 11 ultrasonic anemometers of 325m meteorological observation tower in Beijing during 2013-2015. It lays a foundation for further determination of fine wind field model in Beijing area. The main work is as follows: 1) the wind speed and wind direction in Beijing urban area are statistically analyzed. The results show that the wind speed and direction of Beijing urban area show obvious seasonal characteristics, most of the strong winds occur in spring and winter, the dominant wind direction in this paper is the north direction and the NNE direction, the rough length of geomorphology in Beijing urban area is 1.03 m. The zero plane displacement is 32.2 m. 2) the classification standard of atmospheric stability suitable for Beijing urban area is selected. Two kinds of atmospheric stability evaluation parameters, Richardson number and Monin-Obukhovus M-O length, are compared and analyzed. Taking the M-O length as the evaluation parameter W.R.Wood as the classification standard of atmospheric stability in Beijing urban area, the statistical analysis of atmospheric stability in Beijing urban area is carried out. The variation of the samples in the small wind speed interval is not obvious in time or space, but the change in the large wind speed interval is obvious. The proportion of neutral stratification in spring and winter is relatively large, the neutral atmosphere in summer is the least in all seasons, and the unstable atmosphere is the most. During the day and at night, they tend to be unstable and stable, respectively. The steady atmospheric frequency increases obviously with the height increasing, especially in the summer, and the neutral atmospheric frequency decreases obviously with the height in winter.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU119

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