Terrestrial impact of abrupt changes in the North Atlantic thermohaline circulation: Early Holocene, UK
Terrestrial impact of abrupt changes in the North Atlantic thermohaline circulation: Early Holocene, UK
复制标题
北大西洋温盐环流突然变化对陆地的影响：全新世早期，英国
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
J. D. Ball
中科院分区：
文献类型：
--
作者：
J. Marshall;B. Lang;S. Crowley;G. Weedon;P. Calsteren;E. Fisher;R. Holme;J. Holmes;Richard T. Jones;A. Bedford;S. Brooks;J. Bloemendal;K. Kiriakoulakis;J. D. Ball
突然变冷事件是全新世气候的特征，并可能在未来重现。我们使用的湖记录，西北英格兰，Hawes水，量化两个突出的全新世早期气候事件的影响。利用热电离质谱（TIMS）U系分析，对沉积碳酸盐岩（18δOc）的近十年氧同位素记录提供了9350年前和8380年前持续约150年和150年的突然冷事件的证据，这些冷事件与格陵兰冰芯中确认的9.3ka和8.2ka事件相关。在Hawes Water，从摇蚊-中鸟组合推断的7月平均气温在每次事件中下降了1.6 °C。计算表明，同位素漂移主要是由大气降水的同位素组成（18δOp）减少了1.13 ‰引起的;这被解释为对冰盖融化导致的东北大西洋地表水冷却和清新的直接下游响应。在格陵兰和中欧观察到的事件之间的中间强度，其影响与北大西洋温盐环流的部分关闭是一致的。
Abrupt cooling events are features of Holocene climate and may recur in the future. We use lake records from Hawes Water, NW England, to quantify the impact of two prominent early Holocene climatic events. Subdecadal oxygen isotope records from sedimentary carbonate (18δOc), dated using thermal ionization mass spectrometry (TIMS) U-series analyses, provide evidence for abrupt cold events, lasting ∼50 and ∼150 yr at 9350 and 8380 yr ago, which correlate with the 9.3 ka and 8.2 ka events recognized in Greenland ice cores. At Hawes Water, mean July air temperatures, inferred from chirono-mid assemblages, decreased by ∼1.6 °C during each event. Calculations show that the isotopic excursions were dominantly caused by decreases in the isotopic composition of meteoric precipitation (18δOp) by ∼1.3‰; this is interpreted as a direct downstream response to cooling and freshening of northeast Atlantic surface water by melting ice sheets. Intermediate in magnitude between events observed in Greenland and central Europe, the effects are consistent with a partial shutdown of the North Atlantic thermohaline circulation.