气候变化领域集成服务门户(CCPortal): Dynamical Differences Between Short and Long Blocks in the Northern Hemisphere

CCPortal

DOI	10.1029/2020JD034082
	Dynamical Differences Between Short and Long Blocks in the Northern Hemisphere
	Drouard M.; Woollings T.; Sexton D.M.H.; McSweeney C.F.
发表日期	2021
ISSN	2169897X
卷号	126 期号:10
英文摘要	Blocking events are persistent weather systems that strongly impact daily weather and more importantly our societies. One reason behind their strong impact is their potential long duration, as blocking events can last from 5 days up to four-five weeks. However, the mechanisms explaining this difference of duration have not been properly studied yet. Here, we investigate the differences between short blocks, which last 5 days, and long blocks, which last at least 10 days. We take a broad hemispheric and annual approach to this question, while recognizing that other specific factors may play a role in particular region and seasons. We show that long blocks often involve cyclonic Rossby wave breaking, while short blocks are equally associated with cyclonic and anticyclonic wave breaking. This main result is reproduced in a coupled climate model ensemble. The lower number of long anticyclonic blocks might be due to three main reasons: One/the anticyclone is reinforced on the downstream side during anticyclonic blocks which is less conducive to persistence; two/positive synoptic eddy feedback tends to force the mean zonal wind toward a more northward position during anticyclonic blocks, whereas it forces the mean zonal wind to the south of the block during cyclonic blocks, which has been previously shown to be associated with more persistent weather patterns; three/particularly sustained eddy feedback is needed to maintain long anticyclonic blocks. © 2021. The Authors.
英文关键词	blocking duration; blocking dynamics; coupled models; Rossby waves
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185274
作者单位	Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, United Kingdom; Departamento de Física de la Tierra y Astrofísica, Universidad Complutense de Madrid, Madrid, Spain; Met Office Hadley Centre, Exeter, United Kingdom
推荐引用方式 GB/T 7714	Drouard M.,Woollings T.,Sexton D.M.H.,et al. Dynamical Differences Between Short and Long Blocks in the Northern Hemisphere[J],2021,126(10).
APA	Drouard M.,Woollings T.,Sexton D.M.H.,&McSweeney C.F..(2021).Dynamical Differences Between Short and Long Blocks in the Northern Hemisphere.Journal of Geophysical Research: Atmospheres,126(10).
MLA	Drouard M.,et al."Dynamical Differences Between Short and Long Blocks in the Northern Hemisphere".Journal of Geophysical Research: Atmospheres 126.10(2021).