气候变化领域集成服务门户(CCPortal): Tracing north atlantic oscillation forecast errors to stratospheric origins

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DOI	10.1175/JCLI-D-20-0270.1
	Tracing north atlantic oscillation forecast errors to stratospheric origins
	Kolstad E.W.; Wulff C.O.; Domeisen D.I.V.; Woollings T.
发表日期	2020
ISSN	0894-8755
起始页码	9145
结束页码	9157
卷号	33 期号:21
英文摘要	The North Atlantic Oscillation (NAO) is the main driver of weather variability in parts of Eurasia, Greenland, North America, and North Africa on a range of time scales. Successful extended-range NAO predictions would equate to improved predictions of precipitation and temperature in these regions. It has become clear that the NAO is influenced by the stratosphere, but because this downward coupling is not fully reproduced by all forecast models the potential for improved NAO forecasts has not been fully realized. Here, an analysis of 21 winters of subseasonal forecast data from the European Centre for Medium-Range Weather Forecasts monthly forecasting system is presented. By dividing the forecasts into clusters according to their errors in North Atlantic Ocean sea level pressure 15-30 days into the forecasts, we identify relationships between these errors and the state of the stratospheric polar vortex when the forecasts were initialized. A key finding is that the model overestimates the persistence of both the negative NAO response following a weak polar vortex and the positive NAO response following a strong polar vortex. A case in point is the sudden stratospheric warming in early 2019, which was followed by five consecutive weeks of an overestimation of the negative NAO regime. A consequence on the ground was temperature predictions for northern Europe that were too cold. Another important finding is that the model appears to misrepresent the gradual downward impact of stratospheric vortex anomalies. This result suggests that an improved representation and prediction of stratosphere-troposphere coupling in models might yield substantial benefits for extended-range weather forecasting in the Northern Hemisphere midlatitudes. © 2020 American Meteorological Society.
英文关键词	Atmospheric pressure; Errors; Sea level; Vortex flow; European centre for medium-range weather forecasts; Monthly forecasting systems; North Atlantic oscillations; Northern Hemispheres; Stratosphere-troposphere coupling; Stratospheric polar vortex; Sudden stratospheric warming; Temperature prediction; Weather forecasting; climate prediction; North Atlantic Oscillation; Northern Hemisphere; polar vortex; sea level pressure; seasonal variation; stratosphere-troposphere interaction; sudden stratospheric warming; weather forecasting; Atlantic Ocean; Atlantic Ocean (North); Northern Europe
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/171064
作者单位	NORCE Norwegian Research Center, Bjerknes Center for Climate Research, Bergen, Norway; Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland; Department of Physics, University of Oxford, Oxford, United Kingdom
推荐引用方式 GB/T 7714	Kolstad E.W.,Wulff C.O.,Domeisen D.I.V.,et al. Tracing north atlantic oscillation forecast errors to stratospheric origins[J],2020,33(21).
APA	Kolstad E.W.,Wulff C.O.,Domeisen D.I.V.,&Woollings T..(2020).Tracing north atlantic oscillation forecast errors to stratospheric origins.Journal of Climate,33(21).
MLA	Kolstad E.W.,et al."Tracing north atlantic oscillation forecast errors to stratospheric origins".Journal of Climate 33.21(2020).