Volcanic climate forcing preceding the inception of the Younger Dryas: Implications for tracing the Laacher See eruption
Volcanic climate forcing preceding the inception of the Younger Dryas: Implications for tracing the Laacher See eruption
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DOI：
10.1016/j.quascirev.2021.107260
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发表时间：
2021-12
影响因子：
4
通讯作者：
P. Abbott;U. Niemeier;C. Timmreck;F. Riede;J. McConnell;M. Severi;H. Fischer;A. Svensson;
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作者：
P. Abbott;U. Niemeier;C. Timmreck;F. Riede;J. McConnell;M. Severi;H. Fischer;A. Svensson;
从最后一次冰川盛期到当前间冰期的气候变暖被∼长达1300年的冷期所打断，通常被称为年轻仙女木(YD)。对于触发YD突然开始的机制，已经提出了几个假说，包括淡水强迫、外星撞击和火山喷发产生的气溶胶。在这里，我们使用来自格陵兰和南极冰芯的同步硫酸盐和硫磺记录来重建BPGICC05年(格陵兰冰芯年代学2005年，1950年之前；GICC05)之间13,200-12,800年的火山强迫。这一对平流层硫注入的持续重建突出了∼110年的四个主要两极火山信号的集群，以及就在YD开始之前的几个较小的事件。来自该星团的北半球气溶胶累积负荷和辐射强迫超过了共同时代期间火山最活跃的时期，后者经历了显著的数十年尺度冷却，通常被归因于火山效应。Laacher See喷发(LSE)，最近被追溯到13,006±9.9 Cal a BP，属于我们的研究时间窗口，并被认为是YD的触发因素，但到目前为止，格陵兰冰芯中LSE的直接火山印记一直难以捉摸。将模拟的中硫和高硫LSE类型排放情景的硫酸盐沉积与冰芯估计的硫酸盐沉积和半球间不对称比率进行比较，可以将13,025到12,975a BPGICC05之间的几个信号建议为LSE的合理候选者。就在YD开始之前，火山强迫的规模和持续性突出表明，在用于探索触发这一或类似突然冷却事件的机制的未来分析和气候模型实验中，需要考虑平流层硫注入及其辐射强迫。
Climatic warming from the last glacial maximum to the current interglacial period was punctuated by a ∼1300 years long cold period, commonly referred to as the Younger Dryas (YD). Several hypotheses have been proposed for the mechanism triggering the abrupt inception of the YD, including freshwater forcing, an extra-terrestrial impact, and aerosols from volcanic eruptions. Here, we use synchronised sulphate and sulphur records from both Greenland and Antarctic ice cores to reconstruct volcanic forcing between 13,200–12,800 a BPGICC05(years before 1950 CE on the Greenland Ice Core Chronology 2005; GICC05). This continuous reconstruction of stratospheric sulphur injections highlights a ∼110-year cluster of four major bipolar volcanic signals alongside several smaller events just prior to the YD inception. The cumulative Northern Hemisphere aerosol burden and radiative forcing from this cluster exceeds the most volcanically active periods during the Common Era, which experienced notable multidecadal scale cooling commonly attributed to volcanic effects. The Laacher See eruption (LSE), recently redated to 13,006 ± 9 cal a BP, falls within our time window of study and has been proposed as a trigger for the YD but a direct volcanic imprint for the LSE in the Greenland ice cores has thus far proved elusive. Comparison of simulated sulphate deposition for mid- and high-sulphur LSE-type emission scenarios to the ice-core estimated sulphate deposition and interhemispheric asymmetry ratios allows several signals between 13,025 and 12,975 a BPGICC05to be proposed as plausible candidates for the LSE. The magnitude and persistence of volcanic forcing directly preceding the YD inception highlights the need to consider stratospheric sulphur injections and their radiative forcing in future analyses and climate model experiments used to explore the mechanisms that triggered this or similar abrupt cooling events.