Abstract. Dated to ca. 13,000 years ago, the Laacher See (East Eifel Volcanic Zone) eruption was one of the largest mid-latitude Northern Hemisphere volcanic events of the Late Pleistocene. This eruptive event not only impacted local environments and human communities but also NH climate. We have simulated the evolution of the fine ash and sulfur cloud of an LSE-type eruption under present-day meteorological conditions that mirror the empirically known ash transport distribution as derived from geological, palaeo-ecological and archaeological evidence linked directly to the Late Pleistocene eruption of the Laacher See volcano. This evidence has informed our experimental set-up and we simulated corresponding eruptions of different injection altitudes (30, 60 and, 100 hPa) with varying emission strengths of sulfur and fine ash (1.5, 15, 100 Tg SO₂) and at different days in spring. The chosen eruption dates were determined by the stratospheric wind fields to reflect the empirically observed ash lobes. While it proved difficult to replicate the meteorological conditions that likely prevailed 13,000 years ago, our novel simulations suggest that the heating of the ash plays a crucial role for the transport of ash and sulfate. Depending on the altitude of the injection, the volcanic cloud begins to rotate one to three days after the eruption. The rotation, as well as the additional radiative heating of the fine ash, adds a southerly component to the transport vectors. This ash cloud-generated southerly migration process may at least partially explain why, as yet, no Laacher See tephra has been found in Greenlandic ice-cores. Sulfate transport, too, is impacted by the heating of the ash, resulting in a stronger transport to low-latitudes, later arrival of the volcanic cloud in the Arctic regions and, a longer lifetime. Our models throw new light on the likely behaviour of the ash cloud that darkened European skies at the end of the Pleistocene, and serve as significant input for scenarios that consider the risks associated with re-awakened volcanism in the Eifel.

中文翻译：

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Laacher See型喷发后灰云的模拟

摘要。约会至 13,000年前，拉赫湖（Each Eifel火山带）喷发是晚更新世最大的中纬度北半球火山事件之一。这次爆发事件不仅影响了当地环境和人类社区，还影响了新罕布什尔州的气候。我们已经模拟了当今气象条件下LSE型喷发的细灰和硫云的演变，这反映了根据经验已知的灰分运输分布，该分布是从与晚更新世直接相关的地质，古生态和考古证据中得出的拉赫湖见火山。该证据为我们的实验设置提供了依据，并且我们模拟了不同喷射高度（30、60和100 hPa）的相应喷发，其中硫和细灰的排放强度有所变化（1.5、15、100 Tg SO₂）和春季的不同日期。选定的喷发日期由平流层风场确定，以反映经验观察到的灰叶。尽管事实证明很难复制可能在13,000年前流行的气象条件，但我们的新颖模拟表明，灰分的加热对于灰分和硫酸盐的运输起着至关重要的作用。根据注入的高度，火山云在喷发后一到三天开始旋转。细粉尘的旋转以及附加的辐射加热使传输矢量增加了一个偏南的分量。灰云产生的向南迁移过程至少可以部分解释为何，到目前为止，在格陵兰岛冰芯中还没有发现Laacher See tephra。硫酸盐的运输也受到灰分加热的影响，导致向低纬度地区的运输更加强劲，火山云后来到达北极地区，并且使用寿命更长。我们的模型为灰云的可能行为提供了新的视角，该灰云在更新世末期使欧洲天空变暗，并为考虑埃菲尔火山再度唤醒带来的风险的情景提供了重要依据。