Tropical and Subtropical Meridional Latent Heat Transports by Disturbances to the Zonal Mean and Their Role in the General Circulation
Tropical and Subtropical Meridional Latent Heat Transports by Disturbances to the Zonal Mean and Their Role in the General Circulation
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纬向平均扰动引起的热带和亚热带经向潜热输送及其在大气环流中的作用
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发表时间：
2012
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通讯作者：
O. Pauluis
中科院分区：
文献类型：
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作者：
T. Shaw;O. Pauluis
本文分析了四季纬向平均扰动引起的热带、副热带地区纬向潜热输送的谱。运输分为固定和瞬态行星和次行星尺度涡的贡献。静止输送在副热带对流层低层最大，在夏季占主导地位。它是行星尺度的，输送的纬向尺度对应于副热带反气旋的数量。从地面到对流层中层，从热带到副极地纬度，瞬变输送量很大。在所有季节，它都是由次行星尺度的贡献所主导的。向西（向东）传播的波在热带（亚热带和中纬度）的输送中占主导地位。分析表明，虽然总的涡动纬向潜热输送是无缝的，从深热带到极点，它代表了输送的总和，由不同的动力学特征。本文用统计变换欧拉平均公式将涡动输送转化为流函数，对涡动潜热输送在湿等熵环流中的作用进行了评价。在欧拉平均加涡动感热流函数中加入涡动潜热流函数，使亚热带和中纬度地区的质量输送增加了2 - 3倍。结果表明，涡旋输送在穿越副热带边界的输送中占主导地位。在北方夏季，在没有涡动潜热输送的情况下，实际上没有环流。结果突出了副热带反气旋、热带波和斜压波在大气环流中对潜热输送的重要作用。
The spectrum of meridional latent heat transport in the tropics and subtropics by disturbances to the zonal mean during all seasons is analyzed. The transport is divided into stationary and transient planetary- and subplanetary-scale eddy contributions. The stationary transport is largest in the subtropical lower troposphere and dominates the overall transport during summer. It is of planetary scale and the zonal scale of the transport corresponds to the number of subtropical anticyclones. The transient transport is large from the surface up to the midtroposphere and from the tropics to subpolar latitudes. It is dominated by the subplanetary-scale contribution during all seasons. Westward(eastward)-propagating waves dominatethe transport in the tropics (subtropics and midlatitudes). The analysis reveals that, while the total eddy meridional latent heat transport is seamless from the deep tropics to the pole, it represents the sum of transport by distinct dynamical features. The roleof the eddy meridionallatent heat transport in the moist isentropic circulation is assessed using the statistical transformed Eulerian mean formulation, which converts the eddy transports into streamfunctions. The addition of the eddy latent heat streamfunction to the Eulerian mean plus eddy sensible heat streamfunction increases the mass transport by a factor of 2‐3 in the subtropics and midlatitudes. The eddy transport is found to dominate the transport across the subtropical boundary. During Northern Hemisphere summer there is virtually no circulation in the absence of eddy latent heat transport. The results highlight the important role of latent heat transport by subtropical anticyclones and tropical and baroclinic waves in the general circulation.