title: Comparing regional precipitation and temperature extremes in climate model and reanalysis products.
abstract: A growing field of research aims to characterise the contribution of anthropogenic emissions to the likelihood of extreme weather and climate events. These analyses can be sensitive to the shapes of the tails of simulated distributions. If tails are found to be unrealistically short or long, the anthropogenic signal emerges more or less clearly, respectively, from the noise of possible weather. Here we compare the chance of daily land-surface precipitation and near-surface temperature extremes generated by three Atmospheric Global Climate Models typically used for event attribution, with distributions from six reanalysis products. The likelihoods of extremes are compared for area-averages over grid cell and regional sized spatial domains. Results suggest a bias favouring overly strong attribution estimates for hot and cold events over many regions of Africa and Australia, and a bias favouring overly weak attribution estimates over regions of North America and Asia. For rainfall, results are more sensitive to geographic location. Although the three models show similar results over many regions, they do disagree over others. Equally, results highlight the discrepancy amongst reanalyses products. This emphasises the importance of using multiple reanalysis and/or observation products, as well as multiple models in event attribution studies.
authors.affiliation: Climate Change Research Centre and ARC Centre of Excellence for Climate System Science, UNSW Australia, Sydney NSW 2052, Australia.
authors.forename: Oliver
authors.initials: O
authors.lastname: Angélil
authors.affiliation: Climate Change Research Centre and ARC Centre of Excellence for Climate System Science, UNSW Australia, Sydney NSW 2052, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Perkins-Kirkpatrick
authors.affiliation: Climate Change Research Centre and ARC Centre of Excellence for Climate System Science, UNSW Australia, Sydney NSW 2052, Australia.
authors.forename: Lisa V
authors.initials: LV
authors.lastname: Alexander
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Dáithí
authors.initials: D
authors.lastname: Stone
authors.affiliation: Climate Change Research Centre and ARC Centre of Excellence for Climate System Science, UNSW Australia, Sydney NSW 2052, Australia.
authors.forename: Markus G
authors.initials: MG
authors.lastname: Donat
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Wehner
authors.affiliation: National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Shiogama
authors.affiliation: Met Office Hadley Centre, Exeter EX1 3PB, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ciavarella
authors.affiliation: Met Office Hadley Centre, Exeter EX1 3PB, UK.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Christidis
keywords: CAM5.1; Evaluation; Event attribution; Extremes; HadGEM3-A-N216; MIROC5