Structure and dynamics of the stratosphere and mesosphere revealed by VHF radar investigations
Structure and dynamics of the stratosphere and mesosphere revealed by VHF radar investigations
复制标题
VHF 雷达调查揭示的平流层和中间层的结构和动力学
DOI：
10.1007/bf01586465
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发表时间：
1980
影响因子：
2
通讯作者：
J. Röttger
中科院分区：
文献类型：
--
作者：
J. Röttger
大功率VHF雷达能够几乎连续地监测中层大气（平流层和中间层）的三维速度矢量和湍流分布。概述了中层大气的雷达调查方法，并确定了基本参数，即大气结构的平均速度和波动速度以及反射率和持久性。雷达调查的结果表明，对流层顶水平以及平流层下部的稳定性的标准可以推断。除了平均风速外，VHF雷达还可以测量由声重力波引起的瞬时速度。本文讨论了重力波与背景风的相互作用，指出积云对流是平流层低层重力波的有效源。平流层的垂直微观结构表现为薄分层片，其中出现温度阶跃，通过应用海洋温跃层调查的知识来研究平流层的垂直微观结构。可能的起源，如剪切产生和平流层的微观结构的横向对流，进行了讨论。本文回顾了中层重力波的观测结果，并指出了它们与湍流结构的联系。最后，总结了一些有待进一步研究的问题。
Powerful VHF radars are capable of almost continuously monitoring the threedimensional velocity vector and the distribution of turbulence in the middle atmosphere, i.e. the stratosphere and mesosphere. Methods of radar investigations of the middle atmosphere are outlined and the basic parameters, mean and fluctuating velocities as well as reflectivity and persistency of atmospheric structures, are defined. Results of radar investigations are described which show that the tropopause level as well as a criterion on the stability of the lower stratosphere can be deduced. Besides mean wind velocities, VHF radars can measure instantaneous velocities due to acoustic gravity waves. The interaction of gravity waves with the background wind is discussed, and it is shown that cumulus convection is an effective source of gravity waves in the lower stratosphere. The vertical microstructure of the stratosphere, manifesting itself in thin stratified sheets in which temperature steps occur, is investigated by applying knowledge from investigations of the oceanic thermocline. Possible origins, like shear generation and lateral convection of the microstructure of the stratosphere, are discussed. Observations of gravity waves in the mesosphere are reviewed and their connection with turbulence structures is pointed out. Finally, some open questions which could be answered by further VHF radar investigations are summarized.