This study considers the isopycnal eddy transport of mass and passive tracers in eddy-resolving double-gyre quasigeostrophic oceanic circulation. Here we focus on advective transport, whereas a companion paper focuses on eddy-induced diffusive tracer transport. To work towards parameterising eddy tracer transport we quantify the eddy tracer flux using a transport tensor with eddies defined using a spatial filter, which leads to results distinct from those obtained via a temporal Reynolds eddy decomposition. The advection tensor is the antisymmetric part of the transport tensor, and is so named since the associated tracer transport can be expressed as advection of the large-scale tracer field by a rotational eddy-induced velocity (EIV) ${\mathit{u}}_{\ast }^c$ with streamfunction $A$. The EIV ${\mathit{u}}_{\ast }^c$ is fastest ($\sim 1$ m s⁻¹) where eddy activity is strongest, e.g., in the upper layer, near the eastward jet and western boundary current. Our results suggest that a stochastic closure for the eddy transport would be most suitable since $A$ exhibits a probabilistic distribution when conditioned on, for example, the large-scale relative vorticity. Consistent with closures in ocean circulation models, we quantify eddy mass (isopycnal layer thickness) fluxes as eddy-induced advection by the thickness EIV ${\mathit{u}}_{\ast }^h$. The divergent part of ${\mathit{u}}_{\ast }^h$ – the only part relevant for mass transport in the quasigeostrophic limit – tends to be oriented down the thickness gradient suggesting it quantifies some baroclinic eddy effects similar to those parameterised by the Gent & McWilliams (GM90) EIV. Although ${\mathit{u}}_{\ast }^h$ has some qualitative similarities to ${\mathit{u}}_{\ast }^c$, our results suggest that eddy-induced tracer advection is driven by more than just the thickness-determined EIV and, in turn, more than just the GM90 EIV.

本研究考虑了涡旋分辨双环流准地转海洋环流中质量和被动示踪剂的等密度涡流输运。在这里，我们专注于对流传输，而一篇配套论文则专注于涡流诱导的扩散示踪剂传输。为了对涡流示踪剂传输进行参数化，我们使用具有使用空间滤波器定义的涡流的传输张量来量化涡流示踪剂通量，这导致结果与通过时间雷诺涡流分解获得的结果不同。平流张量是传输张量的反对称部分，之所以如此命名是因为相关的示踪剂传输可以表示为通过旋转涡诱导速度 (EIV) 的大规模示踪场的平流${\mathit{你}}_{＊}^C$ 带流函数 $\mathrm{一种}$. EIV${\mathit{你}}_{＊}^C$ 是最快的（$～1$ms ^-1 ) 其中涡旋活动最强，例如在上层，靠近东向急流和西边界流。我们的结果表明，涡流传输的随机闭合将是最合适的，因为$\mathrm{一种}$例如，当以大尺度相对涡度为条件时表现出概率分布。与海洋环流模型中的闭合一致，我们通过厚度 EIV 将涡流质量（等密度层厚度）通量量化为涡流引起的平流${\mathit{你}}_{＊}^H$. 不同的部分${\mathit{你}}_{＊}^H$– 准地转极限中唯一与质量传输相关的部分 – 倾向于沿着厚度梯度向下定向，这表明它量化了一些斜压涡流效应，类似于由 Gent & McWilliams (GM90) EIV 参数化的那些效应。虽然${\mathit{你}}_{＊}^H$ 与 ${\mathit{你}}_{＊}^C$，我们的结果表明，涡流引起的示踪平流不仅仅由厚度决定的 EIV 驱动，反过来，也不仅仅由 GM90 EIV 驱动。