A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures

Abstract Recent studies using regional climate models to make probabilistic projections break important new ground. However, they typically lack cross validation, pull the projections toward agreeing models (which can agree due to shared biases), and ignore model skill at reproducing internal variab...

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Main Authors: Roman Olson, Yanan Fan, Jason P. Evans
Format: Article
Language:English
Published: Wiley 2016-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2016GL069704
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author Roman Olson
Yanan Fan
Jason P. Evans
author_facet Roman Olson
Yanan Fan
Jason P. Evans
author_sort Roman Olson
collection DOAJ
description Abstract Recent studies using regional climate models to make probabilistic projections break important new ground. However, they typically lack cross validation, pull the projections toward agreeing models (which can agree due to shared biases), and ignore model skill at reproducing internal variability when weighing the models. Here we conduct the first, to our knowledge, application of Bayesian model averaging (BMA) to make probabilistic projections using regional climate models (RCMs). We weigh the RCMs from the NARCliM project based on their skill at representing temperature over 12 southeast Australian regions in terms of trend, bias, and internal variability. The weights do not depend on model agreement with other models. Using the weighted ensemble, we provide probabilistic seasonal temperature projections. We cross validate the method, and demonstrate that weighted projections are well calibrated and more precise than the unweighted ones. We find considerable differences between the weighted and the unweighted projections in some cases.
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spelling doaj-art-ae4df0e75a08435aa253467e8392ab562025-08-20T02:31:41ZengWileyGeophysical Research Letters0094-82761944-80072016-07-0143147661766910.1002/2016GL069704A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperaturesRoman Olson0Yanan Fan1Jason P. Evans2Climate Change Research Centre and ARC Centre of Excellence for Climate System Science UNSW Australia Sydney New South Wales AustraliaSchool of Mathematics and Statistics UNSW Australia Sydney New South Wales AustraliaClimate Change Research Centre and ARC Centre of Excellence for Climate System Science UNSW Australia Sydney New South Wales AustraliaAbstract Recent studies using regional climate models to make probabilistic projections break important new ground. However, they typically lack cross validation, pull the projections toward agreeing models (which can agree due to shared biases), and ignore model skill at reproducing internal variability when weighing the models. Here we conduct the first, to our knowledge, application of Bayesian model averaging (BMA) to make probabilistic projections using regional climate models (RCMs). We weigh the RCMs from the NARCliM project based on their skill at representing temperature over 12 southeast Australian regions in terms of trend, bias, and internal variability. The weights do not depend on model agreement with other models. Using the weighted ensemble, we provide probabilistic seasonal temperature projections. We cross validate the method, and demonstrate that weighted projections are well calibrated and more precise than the unweighted ones. We find considerable differences between the weighted and the unweighted projections in some cases.https://doi.org/10.1002/2016GL069704regional climate modelingBayesian model averagingprobabilistic predictionNARCliMsoutheast Australia
spellingShingle Roman Olson
Yanan Fan
Jason P. Evans
A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures
Geophysical Research Letters
regional climate modeling
Bayesian model averaging
probabilistic prediction
NARCliM
southeast Australia
title A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures
title_full A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures
title_fullStr A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures
title_full_unstemmed A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures
title_short A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures
title_sort simple method for bayesian model averaging of regional climate model projections application to southeast australian temperatures
topic regional climate modeling
Bayesian model averaging
probabilistic prediction
NARCliM
southeast Australia
url https://doi.org/10.1002/2016GL069704
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