Idealized Annually Averaged Macroturbulent Hadley Circulation in a Shallow-Water Model
Idealized Annually Averaged Macroturbulent Hadley Circulation in a Shallow-Water Model
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浅水模型中理想化的年平均宏湍流哈德利环流
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
N. Harnik
中科院分区：
文献类型：
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作者：
Ori Adam;N. Harnik
本文用理想化的浅水模式研究了中纬度涡旋和热驱动的Hadley环流的相互作用。的贡献，每年平均的差异加热，垂直平流的动量从一个固定的边界层，和总效应的涡旋，参数化的瑞利阻尼，包括一个半球不对称阻尼，检查在稳态。该研究发现，相对优势的fedies，作为量化的本地Rossby数，是预测的一个有效的宏观湍流Hadley环流普朗特数Pr。此外，粘性解决方案的Hadley环流宽度和强度，副热带急流振幅，赤道到极点的温度差异规模作为偏离各自的无粘解决方案。半解析解的稳定环流来自弱涡优势（小Pr）的限制，从各自的无粘解决方案的偏差。这些解遵循一个三区域范式：Hadley环流上升分支的弱温度梯度，下降分支的角动量单调减小，以及热带外的修正辐射对流平衡。使用三个区域的解决方案，在完整的解决方案中发现的标度关系解析再现。随着Pr的增加，弱涡优势解偏离完全解，并且可能对Pr无效。1.由于全球三区环流结构的破裂。的Hadley环流加热的基础上的弱涡度优势的解决方案和Pr的响应的定性预测是一致的，更复杂的模式和观测到的大气的结果。
The interaction of midlatitude eddies and the thermally driven Hadley circulation is studied using an idealized shallow-water model on the rotating sphere. The contributions of the annually averaged differential heating, vertical advection of momentum from a stationary boundary layer, and the gross effect of eddies, parameterized by Rayleigh damping, including a hemispherically asymmetric damping, are examined at steady state. Thestudyfindsthattherelativedominanceofeddies,asquantifiedbythelocalRossbynumber,ispredicted by an effective macroturbulent Hadley circulation Prandtl number Pr. In addition, viscous solutions of the Hadley circulation width and strength, subtropical jet amplitude, and equator-to-pole temperature difference scale as deviations from the respective inviscid solutions. Semianalytic solutions for the steady circulation are derived in the limit of weak eddy dominance (small Pr) as deviations from the respective inviscid solutions. These solutions follow a three-region paradigm: weak temperature gradient at the ascending branch of the Hadley circulation, monotonically decreasing angular momentum at the descending branch, and modified radiative‐convective equilibrium at the extratropics. Using the three-region solutions, scaling relations found in the full solutions are reproduced analytically. The weak eddy-dominance solutions diverge from the full solutions as Pr increases and may become invalid for Pr . 1 due to the breakdown of the three-region global circulation structure. The qualitative predictions of the response of the Hadley circulation to heating based on the weak eddydominance solutions and Pr are in agreement with the findings of more complex models and the observed atmosphere.