The 852/3 CE Mount Churchill eruption: examining the potential climatic and societal impacts and the timing of the Medieval Climate Anomaly in the North Atlantic Region-猫眼课题宝

DOI：

10.5194/cp-2021-170

发表时间：

2021-12

期刊：

Climate of the Past

影响因子：

4.3

通讯作者：

中科院分区：

地球科学2区

文献类型：

作者：

H. Mackay;G. Plunkett;B. Jensen;T. Aubry;C. Corona;Woon Mi Kim;M. Toohey;M. Sigl;M. Stoffel;K. Anchukaitis;C. Raible;Matthew S. M. Bolton;Joesph Manning;T. Newfield;Nicola Di Cosmo;F. Ludlow;C. Kostick;Zhen-Ning Yang;Lisa Coyle McClung;M. Amesbury;A. Monteath;P. Hughes;P. Langdon;D. Charman;R. Booth;K. Davies;A. Blundell;G. Swindles

抽象。公元852/3年阿拉斯加丘吉尔山的喷发是第一个千年最大的火山事件之一，震级为6. 7级（VEI 6），火山灰体积为39. 4 - 61. 9 km 3（95%置信度）。这次火山灰沉降的空间范围相当大，隐火山灰（怀特河火山灰东部; WRAe）远至芬兰和波兰。近端生态系统和社会干扰与这次喷发有关;然而，更广泛的火山喷发对气候和社会的影响是未知的。格陵兰冰芯记录显示，火山爆发发生在公元852/3 ± 1年的冬天，火山爆发与相对温和的硫酸盐气溶胶负荷有关，但火山灰和氯的丰度很高。在这里，我们使用古环境重建，历史记录和气候模型模拟评估这次喷发的潜在更广泛的影响。我们还使用852/3 CE丘吉尔火山爆发及其广泛分布的火山灰沉积的怀特河灰（东）（WRAe）的偶然时间来研究温暖的中世纪气候异常时期（MCA;约。公元950-1250年），来自北大西洋地区精确相连的泥炭地。重建的公元852/3年丘吉尔火山爆发的气候强迫潜力与火山爆发的规模相比是中等的，但树木年轮推断的温度报告了公元853年夏季0.8 °C的显著大气冷却。模拟的气候情景也显示公元853年的冷却，尽管平均冷却幅度较小（0.3 °C）。冷却的模拟空间格局一般类似于使用树木年轮推断的温度重建产生的。树木年轮推断的冷却开始之前的喷发日期表明，自然的内部气候变化可能增加了气候系统的进一步冷却的敏感性。重建冷却的幅度也可能表明，这次喷发的气候强迫潜力可能被低估，从而强调需要更深入地了解和考虑卤素和火山灰的作用时，估计喷发气候强迫潜力。精确的比较，从泥炭地横跨北美和欧洲的古环境记录，促进WRAe等时线的存在，揭示没有一致的MCA信号。这些研究结果有助于越来越多的证据表明，MCA水文气候的特点是时间海侵和异质性，而不是一个明确的气候时期。WRAe等时线的存在也表明，没有长期（数十年）的气候或社会影响，从852/3 CE丘吉尔喷发被确定以外的地区接近喷发。欧洲的生存危机的历史证据表明，在年际时间尺度上存在一定程度的时间对应关系，但类似的事件在爆发时期之外也有报道，并且在世纪很常见。公元852/3年的丘吉尔火山爆发使识别和确认一次火山爆发的影响变得更加困难，即使它是精确的日期。

Abstract. The 852/3 CE eruption of Mount Churchill, Alaska, was one of the largest first millennium volcanic events, with a magnitude of 6.7 (VEI 6) and a tephra volume of 39.4–61.9 km3 (95 % confidence). The spatial extent of the ash fallout from this event is considerable and the cryptotephra (White River Ash east; WRAe) extends as far as Finland and Poland. Proximal ecosystem and societal disturbances have been linked with this eruption; however, wider eruption impacts on climate and society are unknown. Greenland ice-core records show that the eruption occurred in winter 852/3 ± 1 CE and that the eruption is associated with a relatively moderate sulfate aerosol loading, but large abundances of volcanic ash and chlorine. Here we assess the potential broader impact of this eruption using palaeoenvironmental reconstructions, historical records and climate model simulations. We also use the fortuitous timing of the 852/3 CE Churchill eruption and its extensively widespread tephra deposition of the White River Ash (east) (WRAe) to examine the climatic expression of the warm Medieval Climate Anomaly period (MCA; ca. 950–1250 CE) from precisely linked peatlands in the North Atlantic region. The reconstructed climate forcing potential of 852/3 CE Churchill eruption is moderate compared with the eruption magnitude, but tree-ring-inferred temperatures report a significant atmospheric cooling of 0.8 °C in summer 853 CE. Modelled climate scenarios also show a cooling in 853 CE, although the average magnitude of cooling is smaller (0.3 °C). The simulated spatial patterns of cooling are generally similar to those generated using the tree-ring-inferred temperature reconstructions. Tree-ring inferred cooling begins prior to the date of the eruption suggesting that natural internal climate variability may have increased the climate system’s susceptibility to further cooling. The magnitude of the reconstructed cooling could also suggest that the climate forcing potential of this eruption may be underestimated, thereby highlighting the need for greater insight into, and consideration of, the role of halogens and volcanic ash when estimating eruption climate forcing potential. Precise comparisons of palaeoenvironmental records from peatlands across North America and Europe, facilitated by the presence of the WRAe isochron, reveal no consistent MCA signal. These findings contribute to the growing body of evidence that characterizes the MCA hydroclimate as time-transgressive and heterogeneous, rather than a well-defined climatic period. The presence of the WRAe isochron also demonstrates that no long-term (multidecadal) climatic or societal impacts from the 852/3 CE Churchill eruption were identified beyond areas proximal to the eruption. Historical evidence in Europe for subsistence crises demonstrate a degree of temporal correspondence on interannual timescales, but similar events were reported outside of the eruption period and were common in the 9th century. The 852/3 CE Churchill eruption exemplifies the difficulties of identifying and confirming volcanic impacts for a single eruption, even when it is precisely dated.

The 852/3 CE Mount Churchill eruption: examining the potential climatic and societal impacts and the timing of the Medieval Climate Anomaly in the North Atlantic Region

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