Case studies in decadal climate predictability
It is well established that, based on knowledge of the initial conditions, important aspects of climate are predictable up to a year ahead. This predictability is primarily associated with the El Niño Southern Oscillation (ENSO). But is climate predictable further ahead? To what extent does knowledg...
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ftceda:oai:cedadocs.ceda.ac.uk:805 2023-05-15T17:36:06+02:00 Case studies in decadal climate predictability Hermanson, Leon Sutton, Rowan 2008-12-08 application/vnd.ms-powerpoint http://cedadocs.ceda.ac.uk/805/ http://cedadocs.ceda.ac.uk/805/1/poster-NCAS08-HermansonSutton.ppt en eng http://cedadocs.ceda.ac.uk/805/1/poster-NCAS08-HermansonSutton.ppt Hermanson, Leon and Sutton, Rowan (2008) Case studies in decadal climate predictability. In: 2008 NCAS Atmospheric Science Conference , 8-10 December, Bristol Ramada Plaza Hotel, UK. Meteorology and Climatology Conference or Workshop Item NonPeerReviewed 2008 ftceda 2020-05-20T10:38:51Z It is well established that, based on knowledge of the initial conditions, important aspects of climate are predictable up to a year ahead. This predictability is primarily associated with the El Niño Southern Oscillation (ENSO). But is climate predictable further ahead? To what extent does knowledge of initial conditions constrain longer-term climate forecasts? In this study we investigate whether there is evidence that climate variables are potentially predictable beyond the generally accepted limit of ENSO predictability. Recognising that predictability is likely to be dependent on initial conditions we consider model-based case studies rather than measures of average predictability. The atmosphere-ocean coupled Hadley Centre HadCM3 model was used in this work. Starting from a pre-indstrial state, a single run was integrated with observed changes in greenhouse gases, volcanic aerosols and the solar cycle for the period 1860-1950. Still using observed forcings, an ensemble of five members was started from the 1950 state and integrated for another 50 years. Each case study consists of two further ensembles started with contemporaneous intial conditions from two different members of the five member ensemble. Four case studies have been completed using ensemble members with opposing large, persistent, regional differences in sea surface temperatures and ocean heat content. The results show clear evidence that knowledge of initial conditions can constrain predictions of climate variables beyond ENSO predictability. In the particular case studies considered, the aspects of climate that are predictable include North Atlantic sea surface temperatures, western European and southeastern US 1.5m temperatures, tropical and subtropical precipitation inthe Pacific and tropical precipitation in the Atlantic. However, predictability of climate variables is strongly dependent on the initial conditions. What are the mechanisms that give rise to these predictable signals? In most cases it seems to be simple persistence of ocean heat content anomalies, but there is also evidence of other mechanisms including ocean dynamics and ocean-atmosphere interaction. We are carrying out further work to interpret and clarify these mechanisms. Conference Object North Atlantic CEDA document repository (Centre for Environmental Data Analysis) Pacific |
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Meteorology and Climatology |
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Meteorology and Climatology Hermanson, Leon Sutton, Rowan Case studies in decadal climate predictability |
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Meteorology and Climatology |
description |
It is well established that, based on knowledge of the initial conditions, important aspects of climate are predictable up to a year ahead. This predictability is primarily associated with the El Niño Southern Oscillation (ENSO). But is climate predictable further ahead? To what extent does knowledge of initial conditions constrain longer-term climate forecasts? In this study we investigate whether there is evidence that climate variables are potentially predictable beyond the generally accepted limit of ENSO predictability. Recognising that predictability is likely to be dependent on initial conditions we consider model-based case studies rather than measures of average predictability. The atmosphere-ocean coupled Hadley Centre HadCM3 model was used in this work. Starting from a pre-indstrial state, a single run was integrated with observed changes in greenhouse gases, volcanic aerosols and the solar cycle for the period 1860-1950. Still using observed forcings, an ensemble of five members was started from the 1950 state and integrated for another 50 years. Each case study consists of two further ensembles started with contemporaneous intial conditions from two different members of the five member ensemble. Four case studies have been completed using ensemble members with opposing large, persistent, regional differences in sea surface temperatures and ocean heat content. The results show clear evidence that knowledge of initial conditions can constrain predictions of climate variables beyond ENSO predictability. In the particular case studies considered, the aspects of climate that are predictable include North Atlantic sea surface temperatures, western European and southeastern US 1.5m temperatures, tropical and subtropical precipitation inthe Pacific and tropical precipitation in the Atlantic. However, predictability of climate variables is strongly dependent on the initial conditions. What are the mechanisms that give rise to these predictable signals? In most cases it seems to be simple persistence of ocean heat content anomalies, but there is also evidence of other mechanisms including ocean dynamics and ocean-atmosphere interaction. We are carrying out further work to interpret and clarify these mechanisms. |
format |
Conference Object |
author |
Hermanson, Leon Sutton, Rowan |
author_facet |
Hermanson, Leon Sutton, Rowan |
author_sort |
Hermanson, Leon |
title |
Case studies in decadal climate predictability |
title_short |
Case studies in decadal climate predictability |
title_full |
Case studies in decadal climate predictability |
title_fullStr |
Case studies in decadal climate predictability |
title_full_unstemmed |
Case studies in decadal climate predictability |
title_sort |
case studies in decadal climate predictability |
publishDate |
2008 |
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http://cedadocs.ceda.ac.uk/805/ http://cedadocs.ceda.ac.uk/805/1/poster-NCAS08-HermansonSutton.ppt |
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Pacific |
geographic_facet |
Pacific |
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North Atlantic |
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North Atlantic |
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http://cedadocs.ceda.ac.uk/805/1/poster-NCAS08-HermansonSutton.ppt Hermanson, Leon and Sutton, Rowan (2008) Case studies in decadal climate predictability. In: 2008 NCAS Atmospheric Science Conference , 8-10 December, Bristol Ramada Plaza Hotel, UK. |
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1766135488921468928 |