Noren Anders J, Bierman Paul R, Steig Eric J, Lini Andrea, Southon John
Department of Geology, University of Vermont, Burlington, Vermont 05405, USA.
Nature. 2002 Oct 24;419(6909):821-4. doi: 10.1038/nature01132.
For the purpose of detecting the effects of human activities on climate change, it is important to document natural change in past climate. In this context, it has proved particularly difficult to study the variability in the occurrence of extreme climate events, such as storms with exceptional rainfall. Previous investigations have established storm chronologies using sediment cores from single lakes, but such studies can be susceptible to local environmental bias. Here we date terrigenous inwash layers in cores from 13 lakes, which show that the frequency of storm-related floods in the northeastern United States has varied in regular cycles during the past 13,000 years (13 kyr), with a characteristic period of about 3 kyr. Our data show four peaks in storminess during the past 14 kyr, approximately 2.6, 5.8, 9.1 and 11.9 kyr ago. This pattern is consistent with long-term changes in the average sign of the Arctic Oscillation, suggesting that modulation of this dominant atmospheric mode may account for a significant fraction of Holocene climate variability in North America and Europe.
为了检测人类活动对气候变化的影响，记录过去气候的自然变化非常重要。在这种情况下，研究极端气候事件（如伴有特大降雨的风暴）发生的变异性已被证明特别困难。以前的调查通过单个湖泊的沉积物岩芯建立了风暴年表，但这类研究可能容易受到当地环境偏差的影响。在这里，我们测定了来自13个湖泊的岩芯中陆源冲刷层的年代，结果表明，在过去13000年（13 kyr）中，美国东北部与风暴相关的洪水频率呈规则周期变化，特征周期约为3 kyr。我们的数据显示，在过去14 kyr中，风暴活动出现了四个峰值，分别约在距今2.6、5.8、9.1和11.9 kyr前。这种模式与北极涛动平均特征的长期变化一致，这表明这种主要大气模式变化可能是北美和欧洲全新世气候变化的一个重要因素。
