Surface climate responses to explosive volcanic eruptions seen in long European temperature records and mid-to-high latitude tree-ring density around the Northern Hemisphere
Surface climate responses to explosive volcanic eruptions seen in long European temperature records and mid-to-high latitude tree-ring density around the Northern Hemisphere
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欧洲长期温度记录和北半球周围中高纬度树木年轮密度中观察到的地表气候对火山喷发的响应
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发表时间：
2013
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通讯作者：
K. Briffa
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作者：
P. Jones;A. Moberg;T. Osborn;K. Briffa
众所周知，爆炸性火山喷发会在喷发后的两到三年内对表面温度产生影响，但由于喷发次数较少（每个世纪发生3-5次大型事件），我们确定影响的能力受到阻碍。我们研究的仪器温度记录，整个北方半球（NH）和欧洲的记录，使用叠加的时代分析大爆发的反应。尽管火山喷发次数有限，我们还是将火山分为两组：热带和北方中高纬度（>40°N）。最明显的反应是在热带火山爆发后，在火山爆发后三年的夏季，北半球的陆地平均温度显着降低，尽管火山爆发的反应时间明显不同。扩展到三个欧洲地区（芬诺斯堪的纳维亚，英格兰中部和中欧）的温度记录显示，在芬诺斯堪的纳维亚热带火山爆发后，夏季冷却显着弱，但在其他两个地区没有明显的影响。芬诺斯堪的纳维亚系列也表明在火山爆发后的第一、第二和第四个冬天（但不是第三个冬天）有轻微的变暖，但没有达到显著水平。缺乏统计意义（在夏季和冬季的区域系列）主要是由于区域系列相比，北半球陆地温度平均值的变化更大，与少量的喷发是一个促成因素。高纬度爆发后显着冷却仅限于夏末在NH在爆发年，在较长的欧洲区域系列的意义不大。我们还评估了较长的记录从中到高纬度地区的NH树轮密度。这一分析进一步突出了重大喷发的缺乏（过去600年中约有20次）以及喷发后冷却空间模式的差异。然而，精确定年的树轮密度系列的NH平均值的响应具有独特的性质，即使在某些日期内喷发的位置仍然未知，但可以使用极端异常的负值来确定过去发生重大喷发的时间。
Explosive volcanic eruptions are known to have an impact on surface temperatures in the two to three years after the eruption, but our ability to determine the impact is impeded by the paucity of eruptions (3-5 large events each century). We examine the response to large eruptions in instrumental temperature records for the whole Northern Hemisphere (NH) and longer European records using superposed epoch analysis. Despite the limited number of eruptions we separate the volcanoes into two groups: tropical and mid-to-high northern latitude (>40°N). The clearest response is after tropical eruptions, where the NH land temperature average cools significantly in the summer months up to three years after the eruptions, although the timing of the response differs markedly from eruption to eruption. Extending the analysis to three European regions (Fennoscandia, Central England and Central Europe) with longer temperature records shows weakly significant summer cooling after tropical eruptions over Fennoscandia, but no discernible impacts in the other two regions. The Fennoscandian series also indicates slight warming in the first, second and fourth winters (but not the third) following the eruptions, but the significance level is not reached. The lack of statistical significance (in the regional series for both summer and winter) is principally due to the greater variability of the regional series compared to the NH land temperature average, with the small number of eruptions being a contributory factor. After higher latitude eruptions significant cooling is restricted to the late summer in the NH during the eruption year, with little of significance in the longer European regional series. We also assess longer records of tree-ring density from the mid-to-high latitude regions of the NH. This analysis further highlights the dearth of major eruptions (about 20 in the last 600 years) and the differences in the spatial patterns of cooling after the eruptions. The response in the NH average of the exactly-dated tree-ring density series, however, is of such a unique character, that extremely anomalous negative values can be used to determine when major eruptions occurred in the past, even though the location of the eruption remains unknown for some dates.