Abstract In a first paper, we presented an in-depth discussion and a computational method (free of the calendar problem) to reckon any kind of latitudinal insolation gradients, LIGs, throughout the Holocene and up to CE 3000. One of the main insights from this exact definition of LIGs is that, unlike what is argued in prior works, during the Holocene, a general classification of LIGs in terms of obliquity signal or climatic precession variations is much more complex, even in summertime. It is especially evident in the Southern Hemisphere, where summer half-year LIGs evolve under the relatively stronger modulation by climatic precession. In this work, the short-term periodicities (high frequency variations in time domain) of all these LIGs are studied by means of the multitaper spectral analysis. The goal is to get more insights on the competing effects between obliquity and climatic precession during the Holocene, and to know how the relative intensity of the obliquity’s periodicities is when compared to the main spectral peaks produced by the climatic precession effects at short time scales (e.g., from annual to decadal bands). Our main result is the clarification of the role of the 18.63 yr periodicity originated in the well known retrograding cycle of the Moons’ orbit. We found that this lunar cycle is always present at a 99 % significance level in all the analysed LIGs, even in winter with solar cycle included. The conceptual explanation of this persistence is based on the fact that all accurate short-term orbital forcing calculation must include the lunar nodal cycle even in climatic precession variations. We propose to use more specific definitions when short-term orbital variations are taken into account in describing Milankovic forcing.

中文翻译：

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全新世 II 中的纬度日照梯度 - 高频变化

摘要在第一篇论文中，我们提出了一个深入的讨论和一种计算方法（没有日历问题）来计算整个全新世和直到 CE 3000 的任何类型的纬度日照梯度 LIG。 LIG 的这个确切定义是，与之前工作中所争论的不同，在全新世期间，根据倾角信号或气候岁差变化对 LIG 进行一般分类要复杂得多，即使在夏季也是如此。这在南半球尤为明显，那里的夏季半年 LIG 在气候岁差的相对较强的调制下演化。在这项工作中，所有这些 LIG 的短期周期性（时域中的高频变化）都通过多锥谱分析进行了研究。目标是更深入地了解全新世期间倾角和气候进动之间的竞争效应，并了解在短时间尺度上与气候进动效应产生的主要光谱峰相比，倾角周期性的相对强度如何（例如，从年度到十年级）。我们的主要结果是阐明了起源于众所周知的月球轨道逆行周期的 18.63 年周期的作用。我们发现这个月球周期在所有分析的 LIG 中始终以 99% 的显着性水平存在，即使在包括太阳周期的冬季也是如此。这种持续性的概念解释是基于这样一个事实，即即使在气候岁差变化中，所有准确的短期轨道强迫计算也必须包括月球节点周期。