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DOI	10.1007/s00382-019-04782-5
	Atmospheric blocking and intercomparison of objective detection methods: flow field characteristics
	Pinheiro M.C.; Ullrich P.A.; Grotjahn R.
发表日期	2019
ISSN	0930-7575
起始页码	4189
结束页码	4216
卷号	53 期号:2020-07-08
英文摘要	Objective methods for identifying and quantifying atmospheric blocking have been developed over recent decades, primarily targeting North Atlantic blocks. Differences arise from these methods, leading to changes in the resultant blocking climatology. To understand these differences, and better inform future assessments built on quantitative detection of blocks, this paper examines blocking properties produced by three different objective detection algorithms over the global extratropics. Blocking criteria examined include 500 hPa geopotential height anomaly (Z∗), column-averaged potential vorticity anomaly (PV∗), and 500 hPa geopotential height gradient (AGP). Results are analyzed for blocking climatologies and for instantaneous blocking patterns, as well as distributions of block size, speed, duration, and distance traveled. The results emphasize physical characteristics of the flow field and the subsequent blocking regions that emerge; overall, PV∗ and Z∗ blocked regions often have higher pattern correlation and spatial similarity, though these two methods also display high agreement with AGP in some instances.Z∗ finds the largest (and greatest number of) blocked regions, while PV∗-detected regions are smallest in all instances except Southern Hemisphere winter. In some cases, PV∗ tracks a nearby jet streak, leading to differences with height-based algorithms. All three algorithms detect some questionable low-latitude blocks that are stationary and persist but do not impair zonal flow, although at different times. Therefore, careful consideration of the algorithm biases is important in future blocking studies. For example, linking extreme weather to detected blocking could vary substantially depending on the algorithm used. © 2019, The Author(s).
英文关键词	Blocking; Climate variability; Climatology; Objective detection
语种	英语
scopus关键词	algorithm; atmospheric blocking; climate change; CMIP; extratropical environment; flow field; geopotential; vorticity; Atlantic Ocean; Atlantic Ocean (North)
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145981
作者单位	Department of Land, Air, and Water Resources, University of California, Davis, 1 Shields Ave, Davis, CA, United States; Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, United States
推荐引用方式 GB/T 7714	Pinheiro M.C.,Ullrich P.A.,Grotjahn R.. Atmospheric blocking and intercomparison of objective detection methods: flow field characteristics[J],2019,53(2020-07-08).
APA	Pinheiro M.C.,Ullrich P.A.,&Grotjahn R..(2019).Atmospheric blocking and intercomparison of objective detection methods: flow field characteristics.Climate Dynamics,53(2020-07-08).
MLA	Pinheiro M.C.,et al."Atmospheric blocking and intercomparison of objective detection methods: flow field characteristics".Climate Dynamics 53.2020-07-08(2019).