摘要
大气边界层及其与自由大气之间的相互作用具有明显的非线性特征,而这些特征是经典Ekman理论所不能描述的,因此,发展中等复杂程度(介于完全模式与经典Ekman模型之间)的大气边界层动力学模式,简称中间模式,对人们从理论上认识大气边界层动力学过程的非线性特征具有重要意义。本文对目前最具代表性的几个中间边界层模型:地转动量近似边界层模型、Ekman动量近似边界层模型以及弱非线性边界层模型进行了总结和分析,阐述了Ekman层主要动力学特征。通过分析上述各模型的理论框架,揭示了各模型的物理意义及其在描述Ekman边界层基本动力特征上的优点和局限性,并指出尽管在细节定量描述上有差异,但各中间模型对Ekman层动力学特征的定性描述具有很好的一致性。对于这些Ekman边界层近似理论模型的进一步应用问题,主要回顾和总结了利用上述模型探讨地形边界层结构、大气锋生过程、低层锋面结构和环流以及边界层日变化、低空急流形成等动力学问题的研究,并对这些研究所揭示的Ekman层动力学特征及其对自由大气低层运动的影响进行了分析,结果表明,这些Ekman边界层近似模型可以较好地揭示大气边界层动力学特征,在大气边界层动力学及其与自由大气相互作用的研究上具有重要价值。另外,还对目前Ekman边界层理论研究中存在的问题进行了一些分析,提出了有待进一步研究的科学问题。
Based on the classical Ekman theory, a series of intermediate Ekman boundary-layer models, which retain the nonlinear advective process while discard embellishments, have been developed with the intention to understand the complex nonlinear features of the Ekman boundary layer and its interaction with the free atmosphere. In this paper, the recent advances in the intermediate boundary-layer theoretical models are reviewed. Several intermediate models such as the Ekman-layer models incorporating geostrophic momentum approximation and Ekman momentum approximation, and the weak nonlinear Ekman-layer model, and the nonlinear features of the Ekman-layer illustrated by these models are a major theme. With inspection of the theoretical frameworks of the limitations of each intermediate model are discussed. It is features in Ekman-layer made by the intermediate models above motioned models, the physical meaning and the found that the qualitative descriptions of the nonlinear are rather consistent though the details may be different. As the application of the intermediate models is concerned, the works applying the intermediate models to investigate the topographic boundary layer, frontogenesis and low-level frontal structures, and the boundary-layer jet are summarized in this article. It is mainly focused on the dynamic characteristics of the Ekman layer and its effect on the low-level structure and circulation of the weather systems illustrated by the models. It is shown that the intermediate boundary-layer models have great potential in illustrating the low-level structures of the weather and climate systems as they are coupled with the free atmospheric models. In addition, the important remaining scientific challenges and a prospectus for future research on the Ekman layer are also discussed.
出处
《气象学报》
CAS
CSCD
北大核心
2005年第5期543-555,共13页
Acta Meteorologica Sinica
基金
国家重点基础研究发展规划项目"南方暴雨"(2004CB18301)
国家自然科学基金项目(40333025
40325014
40333031)
国家教育部科技项目(TRAPOYT
FANEDD11999)
关键词
大气边界层
Ekman边界层动力学
大气动力学
数值模拟
地转动量
惯性力
Ekman boundary layer, Atmospheric dynamics, Geostrophic momentum approximation, Ekman momentum approximation, Intermediate models
