The Ocean's Memory of the Atmosphere: Residence-Time and Ventilation-Rate Distributions of Water Masses
The Ocean's Memory of the Atmosphere: Residence-Time and Ventilation-Rate Distributions of Water Masses
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海洋对大气的记忆：水团的停留时间和通风率分布
DOI：
10.1175/jpo2919.1
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发表时间：
2006
影响因子：
3.5
通讯作者：
M. Holzer
中科院分区：
文献类型：
--
作者：
F. Primeau;M. Holzer
开发了一种概念上新的方法来诊断与示踪剂无关的通气率。 Tracer Green 函数用于根据通风流体在海洋内部的停留时间以及该流体进入和离开内部的位置来划分通风率。在存在由扩散合理地表示的中尺度涡流混合的情况下，重叠入口和出口区域的通风率不能有意义地用单一速率来表征。这是扩散传输的物理结果，在内部花费极短时间的流体元素会导致重叠的入口和出口区域的通风率异常大。因此，通风通常必须以通风率分布为特征， ，根据通风流体在连续表面接触之间在内部花费的时间进行划分。使用离线前向和伴随时间平均 OGCM 来说明海洋与表面通信方式中提供的丰富细节以及密切相关的停留时间 R 的概率密度函数。这些诊断通过将旧水团暴露在大气中或通过形成新的通风水团来量化各个表面区域对于内部海洋通风的相对重要性。模型结果表明，南大洋在海洋通风方面发挥着主导作用，既是新水域进入内陆的区域，又是旧水域首先重新暴露到大气中的区域。
A conceptually new approach to diagnosing tracer-independent ventilation rates is developed. Tracer Green functions are exploited to partition ventilation rates according to the ventilated fluid’s residence time in the ocean interior and according to where this fluid enters and exits the interior. In the presence of mixing by mesoscale eddies, which are reasonably represented by diffusion, ventilation rates for overlapping entry and exit regions cannot meaningfully be characterized by a single rate. It is a physical consequence of diffusive transport that fluid elements that spend an infinitesimally short time in the interior cause singularly large ventilation rates for overlapping entry and exit regions. Therefore, ventilation must generally be characterized by a ventilation-rate distribution, , partitioned according to the time that the ventilated fluid spends in the interior between successive surface contacts. An offline forward and adjoint time-averaged OGCM is used to illustrate the rich detail that and the closely related probability density function of residence times R provide on the way the ocean communicates with the surface. These diagnostics quantify the relative importance of various surface regions for ventilating the interior ocean by either exposing old water masses to the atmosphere or by forming newly ventilated ones. The model results suggest that the Southern Ocean plays a dominant role in ventilating the ocean, both as a region where new waters are ventilated into the interior and where old waters are first reexposed to the atmosphere.