Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty
Accurate forecasts of the ocean state and the estimation of forecast uncertainties are crucial when it comes to providing skilful seasonal predictions. In this study we analyse the predictive skill and reliability of the ocean component in a seasonal forecasting system. Furthermore, we assess the ef...
Published in: | Quarterly Journal of the Royal Meteorological Society |
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Online Access: | https://doi.org/10.1002/qj.3394 https://ora.ox.ac.uk/objects/uuid:edbbc71c-fd9d-4da3-91be-c99feefa975b |
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ftuloxford:oai:ora.ox.ac.uk:uuid:edbbc71c-fd9d-4da3-91be-c99feefa975b 2023-05-15T17:34:23+02:00 Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty Juricke, S Macleod, D Weisheimer, A Zanna, L Palmer, T 2018-09-26 https://doi.org/10.1002/qj.3394 https://ora.ox.ac.uk/objects/uuid:edbbc71c-fd9d-4da3-91be-c99feefa975b unknown Wiley doi:10.1002/qj.3394 https://ora.ox.ac.uk/objects/uuid:edbbc71c-fd9d-4da3-91be-c99feefa975b https://doi.org/10.1002/qj.3394 info:eu-repo/semantics/openAccess CC Attribution (CC BY) CC-BY Journal article 2018 ftuloxford https://doi.org/10.1002/qj.3394 2022-06-28T20:27:23Z Accurate forecasts of the ocean state and the estimation of forecast uncertainties are crucial when it comes to providing skilful seasonal predictions. In this study we analyse the predictive skill and reliability of the ocean component in a seasonal forecasting system. Furthermore, we assess the effects of accounting for model and observational uncertainties. Ensemble forcasts are carried out with an updated version of the ECMWF seasonal forecasting model System 4, with a forecast length of ten months, initialized every May between 1981 and 2010. We find that, for essential quantities such as sea surface temperature and upper ocean 300 m heat content, the ocean forecasts are generally underdispersive and skilful beyond the first month mainly in the Tropics and parts of the North Atlantic. The reference reanalysis used for the forecast evaluation considerably affects diagnostics of forecast skill and reliability, throughout the entire ten‐month forecasts but mostly during the first three months. Accounting for parametrization uncertainty by implementing stochastic parametrization perturbations has a positive impact on both reliability (from month 3 onwards) as well as forecast skill (from month 8 onwards). Skill improvements extend also to atmospheric variables such as 2 m temperature, mostly in the extratropical Pacific but also over the midlatitudes of the Americas. Hence, while model uncertainty impacts the skill of seasonal forecasts, observational uncertainty impacts our assessment of that skill. Future ocean model development should therefore aim not only to reduce model errors but to simultaneously assess and estimate uncertainties. Article in Journal/Newspaper North Atlantic ORA - Oxford University Research Archive Pacific Quarterly Journal of the Royal Meteorological Society 144 715 1947 1964 |
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ORA - Oxford University Research Archive |
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ftuloxford |
language |
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description |
Accurate forecasts of the ocean state and the estimation of forecast uncertainties are crucial when it comes to providing skilful seasonal predictions. In this study we analyse the predictive skill and reliability of the ocean component in a seasonal forecasting system. Furthermore, we assess the effects of accounting for model and observational uncertainties. Ensemble forcasts are carried out with an updated version of the ECMWF seasonal forecasting model System 4, with a forecast length of ten months, initialized every May between 1981 and 2010. We find that, for essential quantities such as sea surface temperature and upper ocean 300 m heat content, the ocean forecasts are generally underdispersive and skilful beyond the first month mainly in the Tropics and parts of the North Atlantic. The reference reanalysis used for the forecast evaluation considerably affects diagnostics of forecast skill and reliability, throughout the entire ten‐month forecasts but mostly during the first three months. Accounting for parametrization uncertainty by implementing stochastic parametrization perturbations has a positive impact on both reliability (from month 3 onwards) as well as forecast skill (from month 8 onwards). Skill improvements extend also to atmospheric variables such as 2 m temperature, mostly in the extratropical Pacific but also over the midlatitudes of the Americas. Hence, while model uncertainty impacts the skill of seasonal forecasts, observational uncertainty impacts our assessment of that skill. Future ocean model development should therefore aim not only to reduce model errors but to simultaneously assess and estimate uncertainties. |
format |
Article in Journal/Newspaper |
author |
Juricke, S Macleod, D Weisheimer, A Zanna, L Palmer, T |
spellingShingle |
Juricke, S Macleod, D Weisheimer, A Zanna, L Palmer, T Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty |
author_facet |
Juricke, S Macleod, D Weisheimer, A Zanna, L Palmer, T |
author_sort |
Juricke, S |
title |
Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty |
title_short |
Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty |
title_full |
Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty |
title_fullStr |
Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty |
title_full_unstemmed |
Seasonal to annual ocean forecasting skill and the role of model and observational uncertainty |
title_sort |
seasonal to annual ocean forecasting skill and the role of model and observational uncertainty |
publisher |
Wiley |
publishDate |
2018 |
url |
https://doi.org/10.1002/qj.3394 https://ora.ox.ac.uk/objects/uuid:edbbc71c-fd9d-4da3-91be-c99feefa975b |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
doi:10.1002/qj.3394 https://ora.ox.ac.uk/objects/uuid:edbbc71c-fd9d-4da3-91be-c99feefa975b https://doi.org/10.1002/qj.3394 |
op_rights |
info:eu-repo/semantics/openAccess CC Attribution (CC BY) |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/qj.3394 |
container_title |
Quarterly Journal of the Royal Meteorological Society |
container_volume |
144 |
container_issue |
715 |
container_start_page |
1947 |
op_container_end_page |
1964 |
_version_ |
1766133200737796096 |