Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics
Flow-dependent spread (FDS) is a desirable characteristic of probabilistic forecasts; ensemble spread should represent the expected forecast error. However this is difficult to estimate for seasonal hindcasts as they tend to have a relatively small sample size. Here we use a long (110 year) seasonal...
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Online Access: | https://orca.cardiff.ac.uk/id/eprint/168336/ https://doi.org/10.1002/asl.815 |
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:168336 2024-06-23T07:55:06+00:00 Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics MacLeod, Dave O'Reilly, Chris Palmer, Tim Weisheimer, Antje 2018-05-01 https://orca.cardiff.ac.uk/id/eprint/168336/ https://doi.org/10.1002/asl.815 unknown Wiley Open Access MacLeod, Dave https://orca.cardiff.ac.uk/view/cardiffauthors/A2779114W.html orcid:0000-0001-5504-6450 orcid:0000-0001-5504-6450, O'Reilly, Chris, Palmer, Tim and Weisheimer, Antje 2018. Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics. Atmospheric Science Letters 19 (5) , e815. 10.1002/asl.815 https://doi.org/10.1002/asl.815 doi:10.1002/asl.815 Article PeerReviewed 2018 ftunivcardiff https://doi.org/10.1002/asl.815 2024-06-04T23:57:50Z Flow-dependent spread (FDS) is a desirable characteristic of probabilistic forecasts; ensemble spread should represent the expected forecast error. However this is difficult to estimate for seasonal hindcasts as they tend to have a relatively small sample size. Here we use a long (110 year) seasonal hindcast dataset to evaluate FDS in forecasts of boreal winter North Atlantic Oscillation (NAO) and Pacific North American pattern (PNA). A good FDS relationship is found for interannual variations in both the NAO and PNA, with mild underdispersion for negative NAO and PNA events and slight overdispersion for positive NAO. Decadal-scale variability is seen in forecast errors but not in ensemble spread, which shows little variation on this timescale. Links between forecast errors and tropical heating anomalies are also investigated, though no strong links are found. However, a weak link between strong El Niño warming in the East Pacific and reduced PNA error is suggested. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Cardiff University: ORCA (Online Research @ Cardiff) Pacific Atmospheric Science Letters 19 5 |
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Open Polar |
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Cardiff University: ORCA (Online Research @ Cardiff) |
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ftunivcardiff |
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description |
Flow-dependent spread (FDS) is a desirable characteristic of probabilistic forecasts; ensemble spread should represent the expected forecast error. However this is difficult to estimate for seasonal hindcasts as they tend to have a relatively small sample size. Here we use a long (110 year) seasonal hindcast dataset to evaluate FDS in forecasts of boreal winter North Atlantic Oscillation (NAO) and Pacific North American pattern (PNA). A good FDS relationship is found for interannual variations in both the NAO and PNA, with mild underdispersion for negative NAO and PNA events and slight overdispersion for positive NAO. Decadal-scale variability is seen in forecast errors but not in ensemble spread, which shows little variation on this timescale. Links between forecast errors and tropical heating anomalies are also investigated, though no strong links are found. However, a weak link between strong El Niño warming in the East Pacific and reduced PNA error is suggested. |
format |
Article in Journal/Newspaper |
author |
MacLeod, Dave O'Reilly, Chris Palmer, Tim Weisheimer, Antje |
spellingShingle |
MacLeod, Dave O'Reilly, Chris Palmer, Tim Weisheimer, Antje Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics |
author_facet |
MacLeod, Dave O'Reilly, Chris Palmer, Tim Weisheimer, Antje |
author_sort |
MacLeod, Dave |
title |
Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics |
title_short |
Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics |
title_full |
Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics |
title_fullStr |
Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics |
title_full_unstemmed |
Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics |
title_sort |
flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics |
publisher |
Wiley Open Access |
publishDate |
2018 |
url |
https://orca.cardiff.ac.uk/id/eprint/168336/ https://doi.org/10.1002/asl.815 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
MacLeod, Dave https://orca.cardiff.ac.uk/view/cardiffauthors/A2779114W.html orcid:0000-0001-5504-6450 orcid:0000-0001-5504-6450, O'Reilly, Chris, Palmer, Tim and Weisheimer, Antje 2018. Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics. Atmospheric Science Letters 19 (5) , e815. 10.1002/asl.815 https://doi.org/10.1002/asl.815 doi:10.1002/asl.815 |
op_doi |
https://doi.org/10.1002/asl.815 |
container_title |
Atmospheric Science Letters |
container_volume |
19 |
container_issue |
5 |
_version_ |
1802647529141043200 |