Abstract. Many palaeoclimate proxies share one challenging property: they are not only driven by the climatic variable of interest, e.g., temperature, but they are also influenced by secondary effects which cause, among other things, increased variability, frequently termed noise. Noise in individual proxy records can be reduced by averaging the records, but the effectiveness of this approach depends on the correlation of the noise between the records and therefore on the spatial scales of the noise-generating processes. Here, we review and apply this concept in the context of Antarctic ice-core isotope records to determine which core locations are best suited to reconstruct local-to-regional-scale temperatures. Using data from a past-millennium climate model simulation equipped with stable isotope diagnostics we intriguingly find that even for a local temperature reconstruction the optimal sampling strategy is to combine a local ice core with a more distant core ~ 500–1000 km away. A similarly large distance between cores is also optimal for reconstructions that average more than two isotope records. We show that these findings result from the interplay of the two spatial scales of the correlation structures associated with the temperature field and with the noise generated by precipitation intermittency. Our study helps to maximise the usability of existing Antarctic ice cores and to optimally plan future drilling campaigns. It also broadens our knowledge on the processes that shape the isotopic record and their typical correlation scales. Finally, the presented method can be directly extended to determine optimal sampling strategies for other palaeoclimate reconstruction problems.

中文翻译：

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降水间歇如何为南极冰芯温度重建设定最佳采样距离

摘要。许多古气候代理共享一个具有挑战性的特性：它们不仅受到感兴趣的气候变量（例如温度）的驱动，而且还受到次级影响的影响，这些次级影响尤其会导致可变性（通常称为噪声）。可以通过对记录进行平均来减少单个代理记录中的噪声，但是此方法的有效性取决于记录之间的噪声相关性，因此取决于噪声生成过程的空间尺度。在这里，我们回顾并在南极冰芯同位素记录的背景下应用此概念，以确定哪些岩心位置最适合重建局部到区域尺度的温度。有趣的是，使用来自过去千年气候模式模拟的数据，该模拟程序配备了稳定的同位素诊断程序，我们发现，即使对于局部温度重建，最佳采样策略是将局部冰芯与更远的核（约500-1000 km）组合在一起。对于平均两个以上同位素记录的重建，岩心之间的类似距离也是最佳的。我们表明，这些发现是由于与温度场和降水间歇产生的噪声有关的相关结构的两个空间尺度之间相互作用的结果。我们的研究有助于最大限度地利用现有南极冰芯，并优化计划未来的钻探活动。它还拓宽了我们对形成同位素记录及其典型相关量表的过程的了解。最后，提出的方法可以直接扩展，以确定其他古气候重建问题的最佳采样策略。我们的研究有助于最大程度地利用现有南极冰芯，并优化计划未来的钻探活动。它还拓宽了我们对形成同位素记录及其典型相关量表的过程的了解。最后，提出的方法可以直接扩展，以确定其他古气候重建问题的最佳采样策略。我们的研究有助于最大程度地利用现有南极冰芯，并优化计划未来的钻探活动。它还拓宽了我们对形成同位素记录及其典型相关量表的过程的了解。最后，提出的方法可以直接扩展，以确定其他古气候重建问题的最佳采样策略。