【作者】 温雅婷；

【导师】 缪启龙；

【作者基本信息】 南京信息工程大学 ， 气候系统与全球变化， 2008， 硕士

【摘要】 大气边界层是地表提供物质和能量的主要扩散和消耗场所。沙漠边界层的研究对沙漠地区陆—气相互作用的模拟有着极其密切的关系。塔克拉玛干沙漠是世界第二大流动沙漠,同时也是我国沙漠的典型代表。对塔克拉玛干流动沙漠腹地近地层的研究,可为沙漠周边城市的发展起到一定作用,同时也加深了沙漠腹地近地层的理论研究。本文利用沙漠腹地大气环境监测站塔中的80m梯度探测资料以及10m高度的OPEC快速响应探测系统的湍流资料,对大气边界层低层的湍流动力特征进行了详细的研究,同时分析了沙尘暴天气下湍流的相关特性,得出以下主要结论:(1)不稳定层结条件和稳定层结条件下,沙漠腹地近地层无因次速度分量方差与稳定度z/L的关系在春季、夏季和冬季均符合相似理论的次幂规律,但最佳幂指数各有不同,并不是唯一的1/3次幂。不稳定层结条件下,无因次温度方差在夏季符合-1/3次幂规律,其余情况离散度较大,规律不明显。近中性层结条件下,三个方向无因次速度分量方差均接近常数,总体表现为:ｕ方向最大,v方向次之,w方向最小:湍流强度也有着同样的规律。(2)沙漠腹地湍流动能、摩擦速度和特征温度均表现出明显的日变化特征。摩擦速度则随稳定或不稳定程度的增大而减小,但最大值出现在z/L=0.2处。(3)沙漠腹地的湍流动能与季节变化有关。夏季略高与春季,冬季最小;湍流总动能中水平方向的动能占主导地位,铅直方向的影响较小;强不稳定层结条件下,热力湍能供给率明显强于机械湍能供给率,稳定层结条件下,两者作用相当。无因次扰动动能e/u_*~2随稳定或不稳定程度的增大而增大,同时离散度也增大。(4)欧拉时间自相关系数则表现出强衰减、渐衰减和缓慢衰减三种类型,且不同层结条件,沙尘天气的欧拉时间自相关系数衰减总体上强于晴天。(5)不稳定层结条件下,春季晴天近地层的铅直脉动以12-17s的周期为主,最小周期表现为1-1.5s,春季沙尘暴时最主要的周期则在6-10s左右,最小周期为0.3-0.5s。稳定层结条件下,春季晴天以周期10-16s的振荡为主,最短周期为0.7-1s,而沙尘暴则在11-20s的周期上振荡最强,最小周期振荡在0.4-0.6s左右。更多还原

【Abstract】 The atmospheric boundary layer is the place of main proliferation and consumed for the surface material and the energy. The research in desert boundary layer has the extremely close relationship to the simulation of desert region Land -Gas interaction. The Taklimakan desert is the world second large flowing desert, simultaneously is also Chinese desert typical representative. The research to boundary layer over hinterland of Taklimakan flowing desert might have active function for desert peripheral city development, simultaneously also makes the desert hinterland surface layer fundamental research deeply. Using these data from the 80m gradient survey and OPEC fast response detection system at 10m height in the desert center atmospheric environment inspection station-tazhong, this article has amply researched the atmospheric boundary lower layer turbulence dynamical characteristics, analyzed the correlative turbulence characteristics in the sand storm weather process, draws the following main conclusions:(1) Under the unstable and stable condition, the relations desert hinterland surface layer dimensionless component of velocity variance with the stability conform to the similarity theory power rules in spring, summer and winter but the best power has the difference respectively, not the only "1/3 power". Under the unstable condition, the dimensionless temperature variance conforms to the "-1/3 power" rules in summer, other seasons the dispersions are large, the rules are not obvious. Under near neutral condition, three direction dimensionless component of velocity variance are close constants, the overall performance is: The u direction is biggest, the v direction next best, the w direction is smallest. The turbulence intensity also has the similar rule.(2) The desert hinterland turbulent kinetic energy, the rubbing speed and the characteristic temperature display obvious diurnal variation characteristic. The rubbing speed reduces along with the stable or unstable degree increases, but the maximum value appears at z/L = -0.2 . The Euler time autocorrelation coefficient displays the over damp and gradually weakens two types.(3) The desert hinterland turbulent kinetic energy is related to the seasonal variation. The TKE is slightly larger in summer than spring, the smallest in winter. Horizontal direction’s turbulent kinetic energy occupies the dominant position, the influence of plumb direction is small in the turbulent total kinetic energy. Under the unstable condition, the thermal energy provides obvious strongly than the mechanical. Under stable condition, both of them effect is equally. The dimensionless perturbation kinetic energy increases along with increase of stable or the unstable degree, the dispersion degree is also increase.(4)The Euler time autocorrelation coefficient displays the fast decay, slow decay and gradual decay three types. During the different condition, Euler time autocorrelation coefficient in the sand storm decays strongly than fine day.(5) Under the unstable condition, the standard day vertical pulsation peculiarity is primarily at the 12-17s time scale, the smallest time scale appears at 1-1.5s in spring, while the sand storm main time scale is about 6-10s, the smallest is 0.3-0.5s. Under the stable condition, at the standard day the time scale is around 10-16s primarily, the most short time scale is at 0.7-1s, the sand storm vibrates at the 11 -20s time scale strongly, the smallest time scale is about 0.4-0.6s.更多还原