Evaluation of dynamical parameters with a three-dimensional mechanistic model of the middle atmosphere
Evaluation of dynamical parameters with a three-dimensional mechanistic model of the middle atmosphere
复制标题
用中层大气三维力学模型评估动力学参数
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
W. Kouker
中科院分区：
文献类型：
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作者：
W. Kouker
介绍了一个中层大气的三维模式。该模型是基于原始方程的完整集合。它被设计用来模拟中层大气的年循环。结果提出了冬至和春分的条件。该模式再现了中层大气环流的主要观测特征：平流层-中层急流和夏季中层顶冷区，尤其是在夏季中层，纬向风逆转，春分弱西风环流。中间层重力波破碎的参数化效应使大气层失去辐射平衡。它们导致了一个纬向环流，在夏至时具有一个单细胞结构，在夏（冬）极向上（向下）运动，在冬半球有一个纬向流，在春分时具有两个细胞结构，在热带向上运动，在极地向下运动。水平矢量场的势场。这表明平流层环流可以由水平无辐散流控制。这是修改的结果，在行星波的相互作用的纬向平均流，这清楚地确定了平流层环流的水平发散的重要作用，更quantitativative的看法。在中层顶区，破碎重力波所产生的力与水平气压梯度力或科里奥利力具有相同的量级，因此地转理论在这里不再适用。这是证实了理想示踪剂和动力示踪剂的位温和等熵位涡（IPV）之间的比较。IPV不再是中层顶区域的保守示踪剂。
A three-dimensional model of the middle atmosphere is introduced. The model is based on the full set of the primitive equations. It is designed to simulate a yearly cycle of the middle atmosphere. Results are presented for the solstice and equinox conditions. The model reproduces the main observed features of the middle atmospheric circulation: the stratospheric-mesospheric jet streams and the cold summer mesopause region at solstice with reversed zonal wind especially in the summer mesosphere, and the weak westerly circulation at equinox. The parameterized effects of breaking gravity waves in the mesosphere drive the atmosphere out of radiative balance. They lead to a meridional circulation with a one-cell structure at solstice with upward (downward) motion over the summer (winter) pole and a meridional flow towards the winter hemisphere and a two-cell structure at equinox with upward motion over the tropics and downward motion over the polar regions. Potential fields are presented for horizontal vector fields. They suggest that the stratospheric circulation can is dominated by horizontally nondivergent flow. This is modified by the results of a more quantitatative view at the interaction of planetary waves on the zonal mean flow, which clearly identifies the essential role of horizontal divergence on the stratospheric circulation. In the mesopause region the forces induced by the breaking gravity waves are of the same order as the horizontal pressure gradient force or the Coriolis force, so that geostrophic theory can no longer be applied here. This is confirmed by a comparison between idealized tracers and the dynamical tracers potential temperature and isentropic potential vorticity (IPV). The IPV is no longer a conservative tracer in the mesopause region.