The Mean Air Flow as Lagrangian Dynamics Approximation and Its Application to Moist Convection
The Mean Air Flow as Lagrangian Dynamics Approximation and Its Application to Moist Convection
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平均气流的拉格朗日动力学近似及其在湿对流中的应用
DOI：
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发表时间：
2016
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通讯作者：
O. Pauluis
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文献类型：
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作者：
O. Pauluis
本文介绍了一种从大气湍流数值模拟中提取热力循环的新方法--拉格朗日动力学近似(Mafalda)。这种方法依赖于两个关键步骤。首先，以高度和当量位温为坐标，通过计算平均环流得到平均轨迹。其次，通过使用它们在相同高度和θe处的条件平均值来近似沿这些轨迹的热力学性质。这给出了经历一组理想化热力学循环的气团性质的完整描述。对流翻转被分解为20个热力学循环，每个循环占总质量输送的5%。每个循环所做的功可以表示为等价的卡诺循环所做的最大功与…之间的差值。
AbstractThis paper introduces the Mean Airflow as Lagrangian Dynamics Approximation (MAFALDA), a new method designed to extract thermodynamic cycles from numerical simulations of turbulent atmospheric flows. This approach relies on two key steps. First, mean trajectories are obtained by computing the mean circulation using height and equivalent potential temperature as coordinates. Second, thermodynamic properties along these trajectories are approximated by using their conditionally averaged values at the same height and θe. This yields a complete description of the properties of air parcels that undergo a set of idealized thermodynamic cycles.MAFALDA is applied to analyze the behavior of an atmosphere in radiative–convective equilibrium. The convective overturning is decomposed into 20 thermodynamic cycles, each accounting for 5% of the total mass transport. The work done by each cycle can be expressed as the difference between the maximum work that would have been done by an equivalent Carnot cycle and...