The Troposphere-to-Stratosphere Transition in Kinetic Energy Spectra and Nonlinear Spectral Fluxes as Seen in ECMWF Analyses
The Troposphere-to-Stratosphere Transition in Kinetic Energy Spectra and Nonlinear Spectral Fluxes as Seen in ECMWF Analyses
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DOI：
10.1175/jas-d-12-0129.1
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发表时间：
2013-02
影响因子：
3.1
通讯作者：
B. H. Burgess;A. Erler;T. Shepherd
中科院分区：
文献类型：
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作者：
B. H. Burgess;A. Erler;T. Shepherd
摘要利用T799型ECMWF的运行分析，计算了垂直水平范围内的整体水平波数动能谱、旋转动能谱通量和熵谱通量。在250 hPa以上，动能谱在陡谱和浅谱范围之间表现出明显的断裂，让人想起飞机数据和高分辨率大气环流模型中的双幂律谱。这个断裂将大尺度的“平衡”状态和中尺度的“不平衡”状态分开，前者旋转流动强烈地支配着发散流动，后者发散能量与旋转能量相当或更大。在230和100 hPa之间，随着流的平衡分量优先衰减，光谱断裂转移到更大的尺度（从n = 60到n = 20，其中n为球面谐波指数）。在整个平流层中，断裂的位置保持相当稳定。分析中的光谱断裂发生在比飞机数据中看到的断裂更大的尺度上. ...
AbstractGlobal horizontal wavenumber kinetic energy spectra and spectral fluxes of rotational kinetic energy and enstrophy are computed for a range of vertical levels using a T799 ECMWF operational analysis. Above 250 hPa, the kinetic energy spectra exhibit a distinct break between steep and shallow spectral ranges, reminiscent of dual power-law spectra seen in aircraft data and high-resolution general circulation models. The break separates a large-scale “balanced” regime in which rotational flow strongly dominates divergent flow and a mesoscale “unbalanced” regime where divergent energy is comparable to or larger than rotational energy. Between 230 and 100 hPa, the spectral break shifts to larger scales (from n = 60 to n = 20, where n is spherical harmonic index) as the balanced component of the flow preferentially decays. The location of the break remains fairly stable throughout the stratosphere. The spectral break in the analysis occurs at somewhat larger scales than the break seen in aircraft data. ...