| 非均匀对流边界层的地转强迫流动和动量输送 |
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| 引用本文： | 蔡旭晖,陈家宜.非均匀对流边界层的地转强迫流动和动量输送[J].大气科学,2003,27(3):381-388. |
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| 作者姓名： | 蔡旭晖 陈家宜 |
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| 作者单位： | 北京大学环境科学中心环境模拟与污染控制国家重点实验室,北京大学物理学院暴雨监测与预报国家重点实验室,北京,100871 |
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| 基金项目： | 国家自然科学基金资助项目49975009、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开放课题和高等学校博士点专项科研基金共同资助 |
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| 摘 要： | 用大涡模拟方法研究地转强迫下的对流边界层流动和地表热力非均匀性影响.模拟重现了典型对流边界层的平均风廓线和动量通量垂直分布.地表热力非均匀性对区域平均风速和动量通量分布无明显影响,但边界层内的局地流动性状和湍流动量输送情况有系统性的改变.下风较热区近地面风速增强而高空流动受到阻塞,上风较冷区之上情况则正好相反.对应于平均流动场的畸变,地表较热区之上边界层大部可以出现动量向上输送的情况,较冷区成为大气动量下传的主要通道.地面应力在较热区增强、较冷区减弱的趋势明显.
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| 关 键 词： | 对流边界层 非均匀 地转强迫 动量输送 大涡模拟 |
Geostrophically Forced Flows and Momentum Transfer in Heterogeneous Convective Boundary Layers |
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| Cai Xuhui and Chen Jiayi.Geostrophically Forced Flows and Momentum Transfer in Heterogeneous Convective Boundary Layers[J].Chinese Journal of Atmospheric Sciences,2003,27(3):381-388. |
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| Authors: | Cai Xuhui and Chen Jiayi |
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| Abstract: | Large-eddy simulations were carried out for geostrophically forced flows in convective boundary layers (CBL), as well as the influence of surface heat heterogeneity. Horizontal mean results over model domain showed typical wind profile and momentum flux distribution in CBL, no matter under condition of homogeneous or heterogeneous surfaces. However, local flow pattern and property of turbulent momentum transfer changed systematically in heterogeneous conditions. Flows over the downstream warmer surface strengthen in lower levels of the CBL and weaken in upper levels. Inverse case occurred over the upstream cooler surface. Correspondent to the skewness of boundary layer mean flow, upward transfer of turbulent momentum in major part of CBL could occur over warmer surface, while there formed a major path for downward momentum transfer over cooler surface. In contrast, surface stress strengthened over warm surface and weakened over the cooler one obviously. |
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| Keywords: | convective boundary layer heterogeneity geostrophical forcing momentum transfer large-eddy simulation |
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