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DOI	10.5194/cp-15-2053-2019
	Two types of North American droughts related to different atmospheric circulation patterns
	Burgdorf A.-M.; Brönnimann S.; Franke J.
发表日期	2019
ISSN	18149324
起始页码	2053
结束页码	2065
卷号	15 期号:6
英文摘要	Proxy-based studies suggest that the southwestern USA is affected by two types of summer drought, often termed Dust Bowl-type droughts and 1950s-type droughts. The spatial drought patterns of the two types are distinct. It has been suggested that they are related to different circulation characteristics, but a lack of observation-based data has precluded further studies. In this paper, we analyze multi-annual summer droughts in North America back to 1600 in tree-ring-based drought reconstructions and in a global, monthly three-dimensional reconstruction of the atmosphere. Using cluster analysis of drought indices, we confirm the two main drought types and find a similar catalog of events as previous studies. These two main types of droughts are then analyzed with respect to 2 m temperatures (T2m), sea-level pressure (SLP), and 500 hPa geopotential height (GPH) in boreal summer. 1950s-type droughts are related to a stronger wave train over the Pacific-North American sector than Dust Bowl-type droughts, whereas the latter show the imprint of a poleward-shifted jet and establishment of a Great Plains ridge. The 500 hPa GPH patterns of the two types differ significantly not only over the contiguous United States and Canada but also over the extratropical North Atlantic and the Pacific. Dust Bowl-type droughts are associated with positive GPH anomalies, while 1950s-type droughts exhibit strong negative GPH anomalies. In comparison with 1950s-type droughts, the Dust Bowl-type droughts are characterized by higher sea-surface temperatures (SSTs) in the northern North Atlantic. Results suggest that atmospheric circulation and SST characteristics not only over the Pacific but also over the extratropical North Atlantic affect the spatial pattern of North American droughts. © 2019 Royal Society of Chemistry. All rights reserved.
语种	英语
scopus关键词	atmospheric circulation; cluster analysis; drought; extratropical environment; sea surface temperature; spatial analysis; tree ring; Atlantic Ocean; Atlantic Ocean (North); Great Plains; United States
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146763
作者单位	Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland; Institute of Geography, University of Bern, Bern, 3012, Switzerland
推荐引用方式 GB/T 7714	Burgdorf A.-M.,Brönnimann S.,Franke J.. Two types of North American droughts related to different atmospheric circulation patterns[J],2019,15(6).
APA	Burgdorf A.-M.,Brönnimann S.,&Franke J..(2019).Two types of North American droughts related to different atmospheric circulation patterns.Climate of the Past,15(6).
MLA	Burgdorf A.-M.,et al."Two types of North American droughts related to different atmospheric circulation patterns".Climate of the Past 15.6(2019).