Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts
A feature‐based approach is introduced to assess the quality of the representation of warm conveyor belts (WCBs) in high‐resolution forecasts of the European Centre for Medium‐range Weather Forecasts (ECMWF). WCBs are moist ascending airstreams in extratropical cyclones, which transport boundary‐lay...
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crwiley:10.1002/qj.2442 2023-12-03T10:26:46+01:00 Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts Madonna, Erica Boettcher, Maxi Grams, Christian M. Joos, Hanna Martius, Olivia Wernli, Heini Schweizerische Nationalfonds zur Förderung der Wissenschaftlichen Forschung Deutsche Forschungsgemeinschaft 2014 http://dx.doi.org/10.1002/qj.2442 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.2442 https://onlinelibrary.wiley.com/doi/pdf/10.1002/qj.2442 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/qj.2442 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.2442 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Quarterly Journal of the Royal Meteorological Society volume 141, issue 689, page 1333-1344 ISSN 0035-9009 1477-870X Atmospheric Science journal-article 2014 crwiley https://doi.org/10.1002/qj.2442 2023-11-09T14:25:47Z A feature‐based approach is introduced to assess the quality of the representation of warm conveyor belts (WCBs) in high‐resolution forecasts of the European Centre for Medium‐range Weather Forecasts (ECMWF). WCBs are moist ascending airstreams in extratropical cyclones, which transport boundary‐layer air within 1–2 days poleward to the upper troposphere. The WCB outflow is typically characterised by low potential vorticity (PV), amplifying upper‐level ridges and in turn modifying the jet stream and downstream Rossby wave evolution. Therefore the correct representation of WCBs can be essential for medium‐range weather prediction. A three‐component verification measure PAL is introduced, measuring errors in the WCB outflow's PV anomaly ( P component), the amplitude of the WCB ( A component), and the location of the outflow ( L component). The PAL approach is applied to North Atlantic WCBs in ECMWF forecasts during three winters between 2002/2003 and 2010/2011. For the latest winter, the PAL results are also compared to the anomaly correlation coefficient (ACC) of upper‐level PV. It is shown that (i) the representation of WCBs improves for forecasts with a shorter lead time, (ii) PAL values are on average better for more recent forecasts, (iii) recent model versions show no systematic over‐ or underestimation of WCB intensity, (iv) individual medium‐range forecasts can be associated with large errors in particular in the amplitude of WCBs, and (v) the comparison of PAL and the ACC indicates that several poor forecasts in terms of ACC are indeed associated with significant errors in the representation of WCBs. Limitations of this study are also discussed. Article in Journal/Newspaper North Atlantic Wiley Online Library (via Crossref) Quarterly Journal of the Royal Meteorological Society 141 689 1333 1344 |
institution |
Open Polar |
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Wiley Online Library (via Crossref) |
op_collection_id |
crwiley |
language |
English |
topic |
Atmospheric Science |
spellingShingle |
Atmospheric Science Madonna, Erica Boettcher, Maxi Grams, Christian M. Joos, Hanna Martius, Olivia Wernli, Heini Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts |
topic_facet |
Atmospheric Science |
description |
A feature‐based approach is introduced to assess the quality of the representation of warm conveyor belts (WCBs) in high‐resolution forecasts of the European Centre for Medium‐range Weather Forecasts (ECMWF). WCBs are moist ascending airstreams in extratropical cyclones, which transport boundary‐layer air within 1–2 days poleward to the upper troposphere. The WCB outflow is typically characterised by low potential vorticity (PV), amplifying upper‐level ridges and in turn modifying the jet stream and downstream Rossby wave evolution. Therefore the correct representation of WCBs can be essential for medium‐range weather prediction. A three‐component verification measure PAL is introduced, measuring errors in the WCB outflow's PV anomaly ( P component), the amplitude of the WCB ( A component), and the location of the outflow ( L component). The PAL approach is applied to North Atlantic WCBs in ECMWF forecasts during three winters between 2002/2003 and 2010/2011. For the latest winter, the PAL results are also compared to the anomaly correlation coefficient (ACC) of upper‐level PV. It is shown that (i) the representation of WCBs improves for forecasts with a shorter lead time, (ii) PAL values are on average better for more recent forecasts, (iii) recent model versions show no systematic over‐ or underestimation of WCB intensity, (iv) individual medium‐range forecasts can be associated with large errors in particular in the amplitude of WCBs, and (v) the comparison of PAL and the ACC indicates that several poor forecasts in terms of ACC are indeed associated with significant errors in the representation of WCBs. Limitations of this study are also discussed. |
author2 |
Schweizerische Nationalfonds zur Förderung der Wissenschaftlichen Forschung Deutsche Forschungsgemeinschaft |
format |
Article in Journal/Newspaper |
author |
Madonna, Erica Boettcher, Maxi Grams, Christian M. Joos, Hanna Martius, Olivia Wernli, Heini |
author_facet |
Madonna, Erica Boettcher, Maxi Grams, Christian M. Joos, Hanna Martius, Olivia Wernli, Heini |
author_sort |
Madonna, Erica |
title |
Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts |
title_short |
Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts |
title_full |
Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts |
title_fullStr |
Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts |
title_full_unstemmed |
Verification of North Atlantic warm conveyor belt outflows in ECMWF forecasts |
title_sort |
verification of north atlantic warm conveyor belt outflows in ecmwf forecasts |
publisher |
Wiley |
publishDate |
2014 |
url |
http://dx.doi.org/10.1002/qj.2442 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.2442 https://onlinelibrary.wiley.com/doi/pdf/10.1002/qj.2442 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/qj.2442 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.2442 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Quarterly Journal of the Royal Meteorological Society volume 141, issue 689, page 1333-1344 ISSN 0035-9009 1477-870X |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/qj.2442 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
141 |
container_issue |
689 |
container_start_page |
1333 |
op_container_end_page |
1344 |
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1784276184490573824 |