论文标题
辣理论重新审视，对中性密度，正交性和被动性有了新的看法
Spiciness theory revisited, with new views on neutral density, orthogonality and passiveness
论文作者
论文摘要
本文阐明了构建辣味变量最佳表征海水质量的理论基础。确定了三种基本成分：1）材料密度变量$γ$，如可行的中性； 2）材料状态函数$ξ$独立于$γ$，但否则是任意的； 3）$γ$的经验确定的参考函数$ξ_r（γ）$代表了概念上的无味海洋中$ξ$的想象行为。成分1）是必需的，因为与通常假定的相反，不是在$ξ$（例如正交性）上施加的属性决定了其动力学惰性，而是中立性的$γ$。第一个关键结果是，正如McDougall and Giles（1987）最初提出的那样，它是异常$ξ'=ξ-ξ_r（γ）$，而不是$ξ$，这是最适合表征海洋水质量的变量。第二个关键结果是正常化的$ξ'$的海洋部分似乎对$ξ$的选择相对不敏感，这是Jackett and McDougall（1985）首先建议的。还认为，$ \ nablaξ'$对物理空间的正交性比辣盐空间中的正交理论更为明显，尽管在Thermohaline空间中，尽管如何使用它来限制$ξ$和$ξ_r（γ）的选择，但仍被完全阐明。结果很重要，因为它们统一了在文献中定义和使用辣味的各种方式。他们还提供了一个严格的理论基础，证明追求全球定义的材料密度变量最大化中立。为了说明后一点，本文提出了作者最近开发的热力学中性密度的新实现，并解释了如何调整现有的辣味/spicity的定义以与之合作。
This paper clarifies the theoretical basis for constructing spiciness variables optimal for characterising ocean water masses. Three essential ingredients are identified: 1) a material density variable $γ$ that is as neutral as feasible; 2) a material state function $ξ$ independent of $γ$, but otherwise arbitrary; 3) an empirically determined reference function $ξ_r(γ)$ of $γ$ representing the imagined behaviour of $ξ$ in a notional spiceless ocean. Ingredient 1) is required because contrary to what is often assumed, it is not the properties imposed on $ξ$ (such as orthogonality) that determine its dynamical inertness but the degree of neutrality of $γ$. The first key result is that it is the anomaly $ξ' = ξ- ξ_r(γ)$, rather than $ξ$, that is the variable the most suited for characterising ocean water masses, as originally proposed by McDougall and Giles (1987). The second key result is that oceanic sections of normalised $ξ'$ appear to be relatively insensitive to the choice of $ξ$, as first suggested by Jackett and McDougall (1985). It is also argued that orthogonality of $\nabla ξ'$ to $\nabla γ$ in physical space is more germane to spiciness theory than orthogonality in thermohaline space, although how to use it to constrain the choices of $ξ$ and $ξ_r(γ)$ remains to be fully elucidated. The results are important for they unify the various ways in which spiciness has been defined and used in the literature. They also provide a rigorous theoretical basis justifying the pursuit of a globally defined material density variable maximising neutrality. To illustrate the latter point, this paper proposes a new implementation of the author's recently developed thermodynamic neutral density and explains how to adapt existing definitions of spiciness/spicity to work with it.
