Using the depth (z) and density (ϱ) frameworks, we analyze local contributions to AMOC variability in a 900-year simulation with the AWI climate model. Both frameworks reveal a consistent interdecadal variability; however, the correlation between their maxima deteriorates on year-to-year scales. We demonstrate the utility of analyzing the spatial patterns of sinking and diapycnal transformations through depth levels and isopycnals. The success of this analysis relies on the spatial binning of these maps which is especially crucial for the maps of vertical velocities which appear to be too noisy in the main regions of upwelling and downwelling because of stepwise bottom topography. Furthermore, we show that the AMOC responds to fast (annual or faster) fluctuations in atmospheric forcing associated with the NAO. This response is more obvious in the ϱ than in the z framework. In contrast, the link between AMOC and deep water production south of Greenland is found for slower fluctuations and is consistent between the frameworks.

中文翻译：

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AWI 气候模型中的 AMOC 变异性和水团变化

使用深度 ( z ) 和密度 ( ϱ) 框架，我们在使用 AWI 气候模型的 900 年模拟中分析了当地对 AMOC 变化的贡献。两个框架都显示出一致的年代际变异性；然而，它们的最大值之间的相关性逐年恶化。我们展示了通过深度水平和等密度线分析下沉和穿深转换的空间模式的实用性。该分析的成功依赖于这些地图的空间分箱，这对于垂直速度图尤其重要，垂直速度图由于阶梯式底部地形而在上升流和下降流的主要区域显得过于嘈杂。此外，我们表明 AMOC 响应与 NAO 相关的大气强迫的快速（年度或更快）波动。这种反应在ϱ比在z框架中。相比之下，发现 AMOC 与格陵兰以南深水生产之间的联系波动较慢，并且在框架之间是一致的。