气候变化领域集成服务门户(CCPortal): Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations

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DOI	10.5194/acp-20-8441-2020
	Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations
	Korhonen N.; Hyvärinen O.; Kämäraïnen M.; Richardson D.S.; Järvinen H.; Gregow H.
发表日期	2020
ISSN	1680-7316
起始页码	8441
结束页码	8451
卷号	20 期号:14
英文摘要	The strength of the stratospheric polar vortex influences the surface weather in the Northern Hemisphere in winter; a weaker (stronger) than average stratospheric polar vortex is connected to negative (positive) Arctic Oscillation (AO) and colder (warmer) than average surface temperatures in northern Europe within weeks or months. This holds the potential for forecasting in that timescale. We investigate here if the strength of the stratospheric polar vortex at the start of the forecast could be used to improve the extended-range temperature forecasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) and to find periods with higher prediction skill scores. For this, we developed a stratospheric wind indicator (SWI) based on the strength of the stratospheric polar vortex and the phase of the AO during the following weeks. We demonstrate that there was a statistically significant difference in the observed surface temperature in northern Europe within the 3-6 weeks, depending on the SWI at the start of the forecast. When our new SWI was applied in post-processing the ECMWF's 2-week mean temperature reforecasts for weeks 3-4 and 5-6 in northern Europe during boreal winter, the skill scores of those weeks were slightly improved. This indicates there is some room for improving the extended-range forecasts, if the stratosphere-troposphere links were better captured in the modelling. In addition to this, we found that during the boreal winter, in cases where the polar vortex was weak at the start of the forecast, the mean skill scores of the 3-6 weeks' surface temperature forecasts were higher than average. © 2020 Author(s).
语种	英语
scopus关键词	Arctic Oscillation; data processing; polar vortex; statistical analysis; stratosphere; surface temperature; weather forecasting; Europe
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/141212
作者单位	Weather and Climate Change Impact Research, Finnish Meteorological Institute, Helsinki, Finland; European Centre for Medium-Range Weather Forecasts (ECMWF), Reading, United Kingdom; Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
推荐引用方式 GB/T 7714	Korhonen N.,Hyvärinen O.,Kämäraïnen M.,et al. Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations[J],2020,20(14).
APA	Korhonen N.,Hyvärinen O.,Kämäraïnen M.,Richardson D.S.,Järvinen H.,&Gregow H..(2020).Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations.Atmospheric Chemistry and Physics,20(14).
MLA	Korhonen N.,et al."Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations".Atmospheric Chemistry and Physics 20.14(2020).