气候变化领域集成服务门户(CCPortal): Evidence for cooler European summers during periods of changing meltwater flux to the North Atlantic

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DOI	10.1073/pnas.0406594101
	Evidence for cooler European summers during periods of changing meltwater flux to the North Atlantic
	Heiri O.; Tinner W.; Lotter A.F.
发表日期	2004
ISSN	0027-8424
起始页码	15285
结束页码	15288
卷号	101 期号:43
英文摘要	We analyzed fossil chironomids (nonbiting midges) and pollen in two lake-sediment records to reconstruct and quantify Holocene summer-temperature fluctuations in the European Alps. Chironomid and pollen records indicate five centennial-scale cooling episodes during the early- and mid-Holocene. The strongest temperature declines of ≈1°C are inferred at ≈10,700-10,500 and 8,200-7,600 calibrated 14C years B.P., whereas other temperature fluctuations are of smaller amplitude. Two forcing mechanisms have been presented recently to explain centennial-scale climate variability in Europe during the early- and mid-Holocene, both involving changes in Atlantic thermohaline circulation. In the first mechanism, changes in meltwater flux from the North American continent to the North Atlantic are responsible for changes in the Atlantic thermohaline circulation, thereby affecting circum-Atlantic climate. In the second mechanism, solar variability is the cause of Holocene climatic fluctuations, possibly triggering changes in Atlantic thermohaline overturning. Within their dating uncertainty, the two major cooling periods in the European Alps are coeval with substantial changes in the routing of North American freshwater runoff to the North Atlantic, whereas quantitatively, our climatic reconstructions show a poor agreement with available records of past solar activity. Thus, our results suggest that, during the early- and mid-Holocene, freshwater-induced Atlantic circulation changes had stronger influence on Alpine summer temperatures than solar variability and that Holocene thermohaline circulation reductions have led to summer-temperature declines of up to 1°C in central Europe.
语种	英语
scopus关键词	fresh water; amplitude modulation; article; climate; Europe; human; pollen; priority journal; seasonal variation; solar energy; summer; temperature sensitivity; Chironomidae
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159194
作者单位	Heiri, O., Department of Palaeoecology, Lab. of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, Netherlands; Tinner, W., Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland; Lotter, A.F., Department of Palaeoecology, Lab. of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, Netherlands
推荐引用方式 GB/T 7714	Heiri O.,Tinner W.,Lotter A.F.. Evidence for cooler European summers during periods of changing meltwater flux to the North Atlantic[J],2004,101(43).
APA	Heiri O.,Tinner W.,&Lotter A.F..(2004).Evidence for cooler European summers during periods of changing meltwater flux to the North Atlantic.Proceedings of the National Academy of Sciences of the United States of America,101(43).
MLA	Heiri O.,et al."Evidence for cooler European summers during periods of changing meltwater flux to the North Atlantic".Proceedings of the National Academy of Sciences of the United States of America 101.43(2004).