Half-precession signals in Lake Ohrid (Balkan) and their spatio-temporal relations to climate records from the European realm
Half-precession signals in Lake Ohrid (Balkan) and their spatio-temporal relations to climate records from the European realm
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DOI：
10.1016/j.quascirev.2022.107413
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发表时间：
2022-03
影响因子：
4
通讯作者：
A. Ulfers;C. Zeeden;S. Voigt;Mehrdad Sardar Abadi;T. Wonik
中科院分区：
文献类型：
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作者：
A. Ulfers;C. Zeeden;S. Voigt;Mehrdad Sardar Abadi;T. Wonik
半岁差（HP）周期（~ 9000 - 12000年）的性质虽然在许多记录中被确认，但仍然知之甚少。在这里，我们将重点放在Ohrid湖以及来自欧洲和北大西洋地区的各种不同的海洋和陆地代理记录中的HP信号上。我们的研究考察了从早/中更新世到现在的高温信号的时间演变，讨论了地中海和欧洲纬度的结果，并评估了高温信号随时间变化反映气候系统连通性的潜力。我们对去除经典轨道周期（偏心，倾角，进动）和高频信号的数据集应用滤波器，以专门关注HP信号的带宽。利用演化小波谱和相关技术研究了不同记录下的频率演化。除了高压旋回与间冰期的联系之外，我们在几个代用记录的较年轻部分看到了更明显的高压信号。尽管在所有被调查的地点都存在高压信号，但与北部的记录相比，我们在东南部观察到更明显的高压信号。后者与HP是赤道信号的假设是一致的，可以通过各种途径向北传播。因此，中纬度和高纬度记录中高温信号的出现可以作为驱动这些途径的机制强度的一个指标。非洲季风可能在这方面发挥了重要作用，因为它的规模直接影响到地中海和南欧的气候系统。
The nature of half-precession (HP) cycles (∼9000–12,000 years), although identified in numerous records, is still poorly understood. Here we focus on HP signals in Lake Ohrid and in a variety of different marine and terrestrial proxy records from Europe and the Northern Atlantic region. Our study examines the temporal evolution of the HP signal from the early/middle Pleistocene to the present, discusses the results across the latitudes of the Mediterranean and Europe, and assesses the potential of the HP to reflect the connectivity of climate systems over time.We apply filters on the datasets that remove the classical orbital cycles (eccentricity, obliquity, precession) and high frequency signals to focus exclusively on the bandwidth of the HP signal. Evolutionary wavelet spectra and correlation techniques are used to study the evolution of frequencies through the different records.Next to a connection of HP cycles to interglacials, we see a more pronounced HP signal in the younger part of several proxy records. Although the HP signal is present in all of the investigated sites, we observe a more pronounced HP signal in the southeast compared to records from the north. The latter is consistent with the assumption that HP is an equatorial signal and can be transmitted northward via various pathways. The appearance of HP signals in mid- and high-latitude records can thus be an indicator for the intensity of the mechanisms driving these pathways. The African Monsoon probably plays a major role in this context, as its magnitude directly influences the climate systems of the Mediterranean and Southern Europe.