Lapointe Francois, Karmalkar Ambarish V, Bradley Raymond S, Retelle Michael J, Wang Feng
Department of Earth, Geographic and Climate Sciences, University of Massachusetts, Amherst, MA, USA.
World Climate Research Programme - Climate and Cryosphere (CliC) Project, University of Massachusetts, Amherst, MA, USA.
Nat Commun. 2024 Jun 3;15(1):4432. doi: 10.1038/s41467-024-48603-8.
Arctic precipitation in the form of rain is forecast to become more prevalent in a warmer world but with seasonal and interannual changes modulated by natural modes of variability. Experiencing rapid hydroclimatic changes in the Arctic, Svalbard serves as an ideal study location due to its exposure to oceanic and atmospheric variability in the North Atlantic region. Here we use climate data from paleoproxies, observations, and a climate model to demonstrate that wet and warm extremes in Svalbard over the last two millennia are linked to the presence of atmospheric blocking regimes over Scandinavia and the Ural mountain region. Rainfall episodes lead to the deposition of coarse sediment particles and high levels of calcium in Linnévatnet, a lake in southwest Svalbard, with the coarsest sediments consistently deposited during atmospheric blocking events. A unique annually resolved sediment record from Linnévatnet confirms that this linkage has been persistent over the past 2000 years. Our record also shows that a millennial-scale decline in Svalbard precipitation ended around the middle of the 19th century, followed by several unprecedented extreme events in recent years. As warming continues and sea ice recedes, future Svalbard floods will become more intense during episodes of Scandinavian and Ural blocking.
在气候变暖的情况下，预计北极地区以降雨形式出现的降水将更为普遍，但季节和年际变化会受到自然变率模式的调节。由于斯瓦尔巴群岛暴露于北大西洋地区的海洋和大气变率之中，在北极经历快速水文气候变化的情况下，它成为了一个理想的研究地点。在这里，我们利用来自古气候代用指标、观测数据和气候模型的气候数据，证明了过去两千年里斯瓦尔巴群岛的湿润和温暖极端事件与斯堪的纳维亚半岛和乌拉尔山脉地区上空的大气阻塞形势有关。降雨事件导致了斯瓦尔巴群岛西南部的林内瓦特湖出现粗颗粒沉积物的沉积以及高钙含量，最粗的沉积物始终是在大气阻塞事件期间沉积的。来自林内瓦特湖的一份独特的逐年解析沉积物记录证实，这种联系在过去2000年里一直存在。我们的记录还表明，斯瓦尔巴群岛降水量在千年尺度上的下降在19世纪中叶左右结束，随后近年来出现了几次前所未有的极端事件。随着气候持续变暖以及海冰消退，未来在斯堪的纳维亚半岛和乌拉尔山脉阻塞期间，斯瓦尔巴群岛的洪水将变得更加严重。
