Maintenance of the Stratospheric Structure in an Idealized General Circulation Model
Maintenance of the Stratospheric Structure in an Idealized General Circulation Model
复制标题
理想化大气环流模型中平流层结构的维持
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
G. Vallis
中科院分区：
文献类型：
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作者：
M. Jucker;S. Fueglistaler;G. Vallis
这项工作探讨了原始方程模型中平流层结构的维持，该模型是通过具有规定的辐射平衡温度场的牛顿冷却强制的。诸如此类的模型非常适合分析和解决有关波传播和平流层相互作用性质的问题。重点放在平流层中下层和半球间的辐射背景状态和强迫变化较大的年平均周期作为基准进行模拟，具有合理的逼真度。相当现实的基本平流层温度结构是理解平流层动力学必要的第一步。首先表明，与以前使用的设置相比，使用基于辐射传输计算的真实辐射背景温度场大大改善了模型平流层的基本结构。然后，探索维持平流层下部温度季节性循环所需的物理过程。研究发现，即使地形强迫很大，改善的平流层和季节性变化的地形强迫驻波本身也不足以在热带地区产生足够幅度的季节性周期。与斜压波活动相关的上升流对热带低平流层有重要影响，对流层斜压活动的季节变化对热带低平流层的季节周期有显着贡献。给定相当现实的平流层基本结构以及驻波活动和对流层斜压不稳定性的季节周期，有可能获得平流层下部的季节周期，其幅度与观测结果相当。
This work explores the maintenance of the stratospheric structure in a primitive equation model that is forced by a Newtonian cooling with a prescribed radiative equilibrium temperature field. Models such as this are well suited to analyze and address questions regarding the nature of wave propagation and troposphere‐ stratosphere interactions. The focus lies on the lower to midstratosphere and the mean annual cycle, with its large interhemispheric variations in the radiative background state and forcing, is taken as a benchmark to be simulated with reasonable verisimilitude. A reasonably realistic basic stratospheric temperature structure is a necessary first step in understanding stratospheric dynamics. It is first shown that using a realistic radiative background temperature field based on radiative transfer calculations substantially improves the basic structure of the model stratospherecompared to previously used setups. Then, the physical processes that are needed to maintain the seasonal cycle of temperature in the lower stratosphere are explored. It is found that an improved stratosphere and seasonally varying topographically forced stationary waves are, in themselves, insufficient to produce a seasonal cycle of sufficient amplitude in the tropics, even if the topographic forcing is large. Upwelling associated with baroclinic wave activityis an important influenceon the tropicallowerstratosphereandthe seasonalvariation oftropospheric baroclinic activity contributes significantly to the seasonal cycle of the lower tropical stratosphere. Given a reasonably realistic basic stratospheric structure and a seasonal cycle in both stationary wave activity and tropospheric baroclinic instability, it is possible to obtain a seasonal cycle in the lower stratosphere of amplitude comparable to the observations.