Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts
The North Atlantic Oscillation (NAO) is the leading mode of variability in the large scale circulation over the North Atlantic in winter, and strongly influences the weather and climate of Europe. On synoptic timescales, the negative phase of the NAO often corresponds to the occurrence of a blocking...
Published in: | Quarterly Journal of the Royal Meteorological Society |
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ftuloxford:oai:ora.ox.ac.uk:uuid:ffc32fe1-5797-4965-9548-7c6edadb882c 2023-05-15T16:26:28+02:00 Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts Parker, TJ Woollings, T Weisheimer, A 2018-08-20 https://doi.org/10.1002/qj.3391 https://ora.ox.ac.uk/objects/uuid:ffc32fe1-5797-4965-9548-7c6edadb882c unknown Wiley doi:10.1002/qj.3391 https://ora.ox.ac.uk/objects/uuid:ffc32fe1-5797-4965-9548-7c6edadb882c https://doi.org/10.1002/qj.3391 info:eu-repo/semantics/openAccess CC Attribution (CC BY) CC-BY Journal article 2018 ftuloxford https://doi.org/10.1002/qj.3391 2022-06-28T20:29:08Z The North Atlantic Oscillation (NAO) is the leading mode of variability in the large scale circulation over the North Atlantic in winter, and strongly influences the weather and climate of Europe. On synoptic timescales, the negative phase of the NAO often corresponds to the occurrence of a blocking episode over Greenland. Hence, the dynamics and predictability of these blocking events is of interest for the prediction of the NAO and its related impacts over a wide region. Ensemble sensitivity analysis utilises the information contained in probabilistic forecast ensembles to calculate a statistical relationship between a forecast metric and some precursor condition. Here the method is applied to 15‐day forecasts of a set of 26 Greenland blocking events using the state‐of‐the‐art European Centre for Medium‐Range Weather Forecasts (ECMWF) forecasting system. The ensemble sensitivity analysis shows that Greenland blocking does not develop in isolation in these forecasts, but instead the blocking is sensitive to remote precursors, such as 500 hPa and 50 hPa geopotential height, particularly in the low‐frequency flow. In general, there are more significant sensitivities to anomalies in the tropics than in the polar regions. Stratospheric sensitivities tend to emerge at later lead times than tropospheric sensitivities. The strongest and most robust sensitivities correspond to a Rossby wave precursor reaching from the Pacific basin across North America. Article in Journal/Newspaper Greenland North Atlantic North Atlantic oscillation ORA - Oxford University Research Archive Greenland Pacific Quarterly Journal of the Royal Meteorological Society 144 716 2358 2379 |
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Open Polar |
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ORA - Oxford University Research Archive |
op_collection_id |
ftuloxford |
language |
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description |
The North Atlantic Oscillation (NAO) is the leading mode of variability in the large scale circulation over the North Atlantic in winter, and strongly influences the weather and climate of Europe. On synoptic timescales, the negative phase of the NAO often corresponds to the occurrence of a blocking episode over Greenland. Hence, the dynamics and predictability of these blocking events is of interest for the prediction of the NAO and its related impacts over a wide region. Ensemble sensitivity analysis utilises the information contained in probabilistic forecast ensembles to calculate a statistical relationship between a forecast metric and some precursor condition. Here the method is applied to 15‐day forecasts of a set of 26 Greenland blocking events using the state‐of‐the‐art European Centre for Medium‐Range Weather Forecasts (ECMWF) forecasting system. The ensemble sensitivity analysis shows that Greenland blocking does not develop in isolation in these forecasts, but instead the blocking is sensitive to remote precursors, such as 500 hPa and 50 hPa geopotential height, particularly in the low‐frequency flow. In general, there are more significant sensitivities to anomalies in the tropics than in the polar regions. Stratospheric sensitivities tend to emerge at later lead times than tropospheric sensitivities. The strongest and most robust sensitivities correspond to a Rossby wave precursor reaching from the Pacific basin across North America. |
format |
Article in Journal/Newspaper |
author |
Parker, TJ Woollings, T Weisheimer, A |
spellingShingle |
Parker, TJ Woollings, T Weisheimer, A Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts |
author_facet |
Parker, TJ Woollings, T Weisheimer, A |
author_sort |
Parker, TJ |
title |
Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts |
title_short |
Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts |
title_full |
Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts |
title_fullStr |
Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts |
title_full_unstemmed |
Ensemble sensitivity analysis of Greenland blocking in medium‐range forecasts |
title_sort |
ensemble sensitivity analysis of greenland blocking in medium‐range forecasts |
publisher |
Wiley |
publishDate |
2018 |
url |
https://doi.org/10.1002/qj.3391 https://ora.ox.ac.uk/objects/uuid:ffc32fe1-5797-4965-9548-7c6edadb882c |
geographic |
Greenland Pacific |
geographic_facet |
Greenland Pacific |
genre |
Greenland North Atlantic North Atlantic oscillation |
genre_facet |
Greenland North Atlantic North Atlantic oscillation |
op_relation |
doi:10.1002/qj.3391 https://ora.ox.ac.uk/objects/uuid:ffc32fe1-5797-4965-9548-7c6edadb882c https://doi.org/10.1002/qj.3391 |
op_rights |
info:eu-repo/semantics/openAccess CC Attribution (CC BY) |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/qj.3391 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
144 |
container_issue |
716 |
container_start_page |
2358 |
op_container_end_page |
2379 |
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1766015392535281664 |