共查询到20条相似文献，搜索用时 265 毫秒
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本文使用位于粗糙和不均匀地形上北京320米气象塔夜间边界层风速、风向和温度资料,用行星边界层u分量第一个极值高度作为行星边界层高度尺度,用边界层内的平均风速和平均位温作为速度和位温特征尺度,分析得到在稳定条件下相似性函数A_m、B_m和C_m以及行星边界层高度的参数化表达式。 分析表明,可以将广义相似性理论推广到粗糙而不均匀地形上的大气边界层中。 相似文献
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大气边界层高度确定及应用研究进展 总被引：2，自引：0，他引：2
大气边界层高度是表征边界层特征的重要参量,影响边界层内水热、物质、能量的垂直分布,也是数值模拟、环境评估中的重要参数。从湍流运动、热力作用、动力作用以及物质分布等多视角总结了大气边界层高度的定义及确定方法,回顾了采用直接观测手段和遥感手段确定大气边界层高度的不同方法,对比了大气边界层高度不同获取手段的优缺点,梳理了大气边界层高度参数化方案,探讨了大气边界层高度确定中存在的问题,并提出未来相关研究和应用可能突破方向。 相似文献
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用大气边界层模式定量地估计城市建筑物的影响,考虑了决定城市大气中杂质扩散的气象参数的动力和热力作用。对莫斯科的边界层的计算,得到了具体日期的粗糙度、大气边界层外部和内部的气象参数以及气象要素和边界层湍流特征的垂直剖面。给出了在城市建筑物的影响下热状况和环流状况参数变化的定量估计。 相似文献
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大气边界层气象学研究综述 总被引：5，自引：2，他引：5
文中回顾了大气边界层气象学的发展历史，总结了目前大气边界层气象学的主要进展，并指出国内外在未来大气边界层气象学研究方面面临的一些主要科学问题，以及对未来大气边界层气象学的发展方向提出若干建议，同时还指出了大气边界层气象学在思想上和方法上应该注意的一些相关问题。 相似文献
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边界层湍流输送的若干问题和大气线性热力学 总被引：16，自引：9，他引：7
总结了大气线性热力学基本理论,讨论了大气边界层的能量和物质输送交叉耦合效应,还讨论了大气系统动力过程和热力过程的交叉耦合效应。分析指出：由于动力过程和热力过程的交叉耦合效应,导致大气边界层能量和物质输送过程除了湍流输送外,还应包括大气辐散和辐合运动对能量和物质的输送。非均匀下垫面大气边界层和对流边界层辐散和辐合运动对能量和物质输送是重要的。在这个基础上,讨论了非均匀下垫面和对流边界层地表能量的平衡问题,非均匀下垫面和对流边界层陆面过程边界层参数化等问题。这些研究不仅丰富了大气边界层物理理论,而且为克服当前大气边界层物理应用中所遇到的困难提供了理论依据。 相似文献
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The temperature and wind profiles in the planetary boundary layer (PBL) are investigated. Assuming stationary and homogeneous conditions, the turbulent state in the PBL is uniquely determined by the external Rossby number and the stratification parameters. In this study, a simple two-layer barotropic model is proposed. It consists of a surface (SL) and overlying Ekman-type layer. The system of dynamic and heat transfer equations is closed usingK theory. In the SL, the turbulent exchange coefficient is consistent with the results of similarity theory while in the Ekman layer, it is constant. Analytical solutions for the wind and temperature profiles in the PBL are obtained. The SL and thermal PBL heights are properly chosen functions of the stratification so that from the solutions for wind and temperature, the PBL resistance laws can be easily deduced. The internal PBL characteristics necessary for the calculation (friction velocity, angle between surface and geostrophic winds and internal stratification parameter) are presented in terms of the external parameters. Favorable agreement with experimental data and model results is demonstrated. The simplicity of the model allows it to be incorporated in large-scale weather prediction models as well as in the solution of various other meteorological problems. 相似文献
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边界层特征参数对边界层顶垂直速度的影响 总被引：1，自引：1，他引：1
本文从正斜压及有层结时的边界层相似理论及阻力定律出发，由边界层顶垂直速度与地面湍应力的关系求出了层结、粗糙度、它们的水平梯度及地转风的水平梯度、斜压性对w的影响的解析式，可用于模式计算。计算结果表明层结影响可使w差1-２个量级，不稳定时粗糙度影响也使w差几倍。除地转涡度决定w外，地转风、层结稳定度和粗糙度及其水平梯度也起了重要作用，还讨论了斜压性的影响。 相似文献
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S. S. Zilitinkevich 《Boundary-Layer Meteorology》1989,49(1-2):1-5
A logarithmic + polynomial approximation is proposed for the vertical temperature profile in a neutrally or stably stratified planetary boundary layer (PBL) in conditions of quasi-stationarity. Using this approximation with the asymptotic logarithmic + linear law of the Monin-Obukhov similarity theory for the near-surface layer and with the Zilitinkevich formula for the PBL thickness allows one to derive an analytical expression for the function C in the heat transfer law, which permits simple parameterization of the thermal interaction between the atmosphere and the underlying medium in terms of external parameters, such as the geostrophic wind velocity and the temperature difference across the PBL. 相似文献
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本文用大气边界层运动方程的数值积分研究了当边界层顶风向不变但风速变化时对大气边界层的内参数u_*/A(u_*为摩擦速度,A为上界风速)和α角(地面风与上界风向的交角)的影响。设上界处风速随时间指数增加及减少,最后趋于定常。在大气正、斜压时,u_*/A及α角的时间变化均是振幅衰减的振荡,最后趋于定常时相应的值。在时间变化过程中的任一时刻,内参数值与当上界条件取该时刻上界风时的定常解结果有一定的差别,严格说,定常时的内参数值并不能直接用于当上界风非定常时。本文还考虑了上界风速非定常对风廓线的影响。 相似文献
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采用与实测较接近的二次函数来表达Ｅｋｍａｎ层中的湍流粘性系数Ｋ，在圆形气压场条件下，求得了山地上空边界层中的风速，进而求得散度、涡度和垂直速度等场变量随高度的分布。并作图分析了这些场变量的一些动力学特征。改进了以往在求解析解时，略去运动方程中湍流粘性力项中的关于高度的一阶导数项，以及取山坡面上风速为零作下边界条件等欠合理欠精确的做法。所求得的风速、散度、涡度和垂直速度均用简单的初等函数表示出来，有助于边界层参数化和深化对边界层动力学的认识。 相似文献
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A resistance law for nonstationary conditions is suggested assuming similarity of the non-dimensional Reynold's stress. Equations of motion for the wind velocity deviations are used for the outer layer. In the wall layer, wall similarity is supposed as usual. Then a matching procedure is used for the derivation of the resistance law. 相似文献
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Methods are developed for the determination of parameters of the atmospheric planetary boundary layer, within the framework of similarity theory based on the external parameters — wind velocity at the upper boundary of the layer, its thickness, air temperature difference between the upper and the lower boundaries, roughness of the underlying surface, and buoyancy forces. The form of the resistance laws is discussed. Determination of the thickness of the stationary and horizontally homogeneous (Ekman) boundary layer is analyzed and generalizations of the latter are suggested for non-stationary and inhomogeneous boundary layers. 相似文献
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S. S. Zilitinkevich 《Boundary-Layer Meteorology》1989,46(4):367-387
The logarithmic + polynomial approximation is suggested for vertical profiles of velocity components in a planetary boundary layer (PBL) at neutral and stable stratification. The resistance law functions A and B are determined on the basis of this approximation, using integral relations derived from the momentum equations, the Monin-Obukhov asymptotic formula for the wind profile in a stably stratified near-surface layer and the known expressions for the PBL depth. This result gives a realistic and convenient method for calculating the surface friction velocity and direction and the total dissipation rate of mean flow kinetic energy in terms of geostrophic velocity, buoyancy flux at the surface, the roughness parameter and the Coriolis parameter. In the course of these derivations a review is given of current views on the main problems of the neutral and stable PBL. 相似文献
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L. Cvitan 《Meteorology and Atmospheric Physics》2006,93(3-4):235-246
Summary The stability parameter μ is suggested as the one which is determinable with satisfying accuracy for routine application by
means of commonly accessible meteorological data at the Molve location (Croatia). The similarity functions applied for vertical
wind speed simulation in the planetary boundary layer (PBL) at Molve were useful for the determination of local stability
classes. Universal similarity functions were applied for unstable and neutral stability, whereas local similarity functions
were established for stable stratification. Wind speed simulations were performed using two types of wind models. The Monin-Obukhov
similarity theory was included in both types. However, it turned out that for the operative determination of the stability
of the 35 m deep lowest layer, the stability parameter μ was locally a better stability parameter than the Monin-Obukhov parameter
z/L. That was possibly because 35 m deep lowest layer sometimes (depending upon stability) includes a large proportion of
the Ekman layer and parameter μ is originally designed for the deeper part of PBL than z/L that is originally designed for
the surface layer. At Molve, the input data for local wind models as well as for the stability parameter μ were wind speed
at 35 m and temperature at 2 and 35 m above the ground. 相似文献
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