Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France
The representation of a high-impact weather (HIW) event over southern France is evaluated in Meteo-France forecasts, and the sensitivity of the HIW forecast to the upstream upper-level flow and the Mediterranean and North Atlantic humidity structure prior to the event is quantified. The event occurr...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/502757 2023-05-15T17:30:12+02:00 Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France Binder, Hanin Rivière, Gwendal Arbogast, Philippe Maynard, Karine Bosser, Pierre Joly, Bruno Labadie, Carole 2021-07 application/application/pdf https://hdl.handle.net/20.500.11850/502757 https://doi.org/10.3929/ethz-b-000502757 en eng Wiley info:eu-repo/semantics/altIdentifier/doi/10.1002/qj.4127 info:eu-repo/semantics/altIdentifier/wos/000687053400001 info:eu-repo/grantAgreement/SNF/Projekte MINT/185049 http://hdl.handle.net/20.500.11850/502757 doi:10.3929/ethz-b-000502757 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International CC-BY Quarterly Journal of the Royal Meteorological Society, 147 (739) diabatic processes dynamics forecast sensitivity high-impact weather humidity NAWDEX numerical weather prediction info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2021 ftethz https://doi.org/20.500.11850/502757 https://doi.org/10.3929/ethz-b-000502757 https://doi.org/10.1002/qj.4127 2022-04-25T14:33:58Z The representation of a high-impact weather (HIW) event over southern France is evaluated in Meteo-France forecasts, and the sensitivity of the HIW forecast to the upstream upper-level flow and the Mediterranean and North Atlantic humidity structure prior to the event is quantified. The event occurred in October 2016 during the international field experiment NAWDEX. The approach of an upper-level potential vorticity (PV) cut-off, referred to as cut-off Sanchez, triggered extreme precipitation over southern France. Many 2- to 7-day ensemble forecasts predicted the maximum of the extreme precipitation and the location of the upper-level PV cut-off too far to the east. This eastward shift primarily resulted from an underestimation of the cut-off intensity two days before the HIW and the subsequent downstream propagation and amplification of these errors in the vicinity of Sanchez. Improving the representation of the cut-off two days before the event significantly improved the forecast quality. Another error source were inaccuracies in the moisture structure in the eastern North Atlantic. Specifically, an underestimation of the moisture in the warm conveyor belt inflow led to errors in the low- and upper-level circulation that eventually contributed to the eastward shift of the HIW two days later. Corrections in the eastern North Atlantic humidity structure further improved the forecast quality. On the other hand, corrections in the Mediterranean humidity structure had only a small impact on the accuracy of the forecast. The findings illustrate the importance of downstream error propagation and moist diabatic processes for the prediction of extreme weather over Europe, and demonstrate how targeted changes in the PV and humidity field a few days in advance can improve the quality of the forecasts. ISSN:0035-9009 ISSN:1477-870X Article in Journal/Newspaper North Atlantic ETH Zürich Research Collection |
institution |
Open Polar |
collection |
ETH Zürich Research Collection |
op_collection_id |
ftethz |
language |
English |
topic |
diabatic processes dynamics forecast sensitivity high-impact weather humidity NAWDEX numerical weather prediction |
spellingShingle |
diabatic processes dynamics forecast sensitivity high-impact weather humidity NAWDEX numerical weather prediction Binder, Hanin Rivière, Gwendal Arbogast, Philippe Maynard, Karine Bosser, Pierre Joly, Bruno Labadie, Carole Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France |
topic_facet |
diabatic processes dynamics forecast sensitivity high-impact weather humidity NAWDEX numerical weather prediction |
description |
The representation of a high-impact weather (HIW) event over southern France is evaluated in Meteo-France forecasts, and the sensitivity of the HIW forecast to the upstream upper-level flow and the Mediterranean and North Atlantic humidity structure prior to the event is quantified. The event occurred in October 2016 during the international field experiment NAWDEX. The approach of an upper-level potential vorticity (PV) cut-off, referred to as cut-off Sanchez, triggered extreme precipitation over southern France. Many 2- to 7-day ensemble forecasts predicted the maximum of the extreme precipitation and the location of the upper-level PV cut-off too far to the east. This eastward shift primarily resulted from an underestimation of the cut-off intensity two days before the HIW and the subsequent downstream propagation and amplification of these errors in the vicinity of Sanchez. Improving the representation of the cut-off two days before the event significantly improved the forecast quality. Another error source were inaccuracies in the moisture structure in the eastern North Atlantic. Specifically, an underestimation of the moisture in the warm conveyor belt inflow led to errors in the low- and upper-level circulation that eventually contributed to the eastward shift of the HIW two days later. Corrections in the eastern North Atlantic humidity structure further improved the forecast quality. On the other hand, corrections in the Mediterranean humidity structure had only a small impact on the accuracy of the forecast. The findings illustrate the importance of downstream error propagation and moist diabatic processes for the prediction of extreme weather over Europe, and demonstrate how targeted changes in the PV and humidity field a few days in advance can improve the quality of the forecasts. ISSN:0035-9009 ISSN:1477-870X |
format |
Article in Journal/Newspaper |
author |
Binder, Hanin Rivière, Gwendal Arbogast, Philippe Maynard, Karine Bosser, Pierre Joly, Bruno Labadie, Carole |
author_facet |
Binder, Hanin Rivière, Gwendal Arbogast, Philippe Maynard, Karine Bosser, Pierre Joly, Bruno Labadie, Carole |
author_sort |
Binder, Hanin |
title |
Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France |
title_short |
Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France |
title_full |
Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France |
title_fullStr |
Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France |
title_full_unstemmed |
Dynamics of forecast-error growth along cut-off Sanchez and its consequence for the prediction of a high-impact weather event over southern France |
title_sort |
dynamics of forecast-error growth along cut-off sanchez and its consequence for the prediction of a high-impact weather event over southern france |
publisher |
Wiley |
publishDate |
2021 |
url |
https://hdl.handle.net/20.500.11850/502757 https://doi.org/10.3929/ethz-b-000502757 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Quarterly Journal of the Royal Meteorological Society, 147 (739) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1002/qj.4127 info:eu-repo/semantics/altIdentifier/wos/000687053400001 info:eu-repo/grantAgreement/SNF/Projekte MINT/185049 http://hdl.handle.net/20.500.11850/502757 doi:10.3929/ethz-b-000502757 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/20.500.11850/502757 https://doi.org/10.3929/ethz-b-000502757 https://doi.org/10.1002/qj.4127 |
_version_ |
1766126031382511616 |