Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations
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 norther...
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ftdoajarticles:oai:doaj.org/article:f8a583301ab44f718a823843b58d067a 2023-05-15T15:13:07+02:00 Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations N. Korhonen O. Hyvärinen M. Kämäräinen D. S. Richardson H. Järvinen H. Gregow 2020-07-01T00:00:00Z https://doi.org/10.5194/acp-20-8441-2020 https://doaj.org/article/f8a583301ab44f718a823843b58d067a EN eng Copernicus Publications https://www.atmos-chem-phys.net/20/8441/2020/acp-20-8441-2020.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-20-8441-2020 1680-7316 1680-7324 https://doaj.org/article/f8a583301ab44f718a823843b58d067a Atmospheric Chemistry and Physics, Vol 20, Pp 8441-8451 (2020) Physics QC1-999 Chemistry QD1-999 article 2020 ftdoajarticles https://doi.org/10.5194/acp-20-8441-2020 2022-12-31T14:59:14Z 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. Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic Atmospheric Chemistry and Physics 20 14 8441 8451 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
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English |
topic |
Physics QC1-999 Chemistry QD1-999 |
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Physics QC1-999 Chemistry QD1-999 N. Korhonen O. Hyvärinen M. Kämäräinen D. S. Richardson H. Järvinen H. Gregow Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
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. |
format |
Article in Journal/Newspaper |
author |
N. Korhonen O. Hyvärinen M. Kämäräinen D. S. Richardson H. Järvinen H. Gregow |
author_facet |
N. Korhonen O. Hyvärinen M. Kämäräinen D. S. Richardson H. Järvinen H. Gregow |
author_sort |
N. Korhonen |
title |
Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations |
title_short |
Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations |
title_full |
Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations |
title_fullStr |
Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations |
title_full_unstemmed |
Adding value to extended-range forecasts in northern Europe by statistical post-processing using stratospheric observations |
title_sort |
adding value to extended-range forecasts in northern europe by statistical post-processing using stratospheric observations |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/acp-20-8441-2020 https://doaj.org/article/f8a583301ab44f718a823843b58d067a |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Atmospheric Chemistry and Physics, Vol 20, Pp 8441-8451 (2020) |
op_relation |
https://www.atmos-chem-phys.net/20/8441/2020/acp-20-8441-2020.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-20-8441-2020 1680-7316 1680-7324 https://doaj.org/article/f8a583301ab44f718a823843b58d067a |
op_doi |
https://doi.org/10.5194/acp-20-8441-2020 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
20 |
container_issue |
14 |
container_start_page |
8441 |
op_container_end_page |
8451 |
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