Approaches to attribution of extreme temperature and precipitation events using multi-model and single-member ensembles of general circulation models

摘要

Extreme temperature and precipitation events occurring in Australia inrecent decades have caused significant socio-economic and environmentalimpacts, and thus determining the factors contributing to these extremes isan active area of research. Many recently occurring record-breakingtemperature and rainfall events have now been examined from an extreme eventattribution (EEA) perspective. This paper describes a set of studies that haveexamined the causes of extreme climate events using various generalcirculation models (GCMs), presenting a comprehensive methodology forGCM-based attribution ofextremes of temperature and precipitation observed on large spatial and temporal scales in Australia. First, we review howCoupled Model Intercomparison Project Phase 5 (CMIP5) models have been usedto examine the changing odds of observed extremes. Second, we review how alarge perturbed initial condition ensemble of a single climate model (CESM)has been used to quantitatively examine the changing characteristics ofAustralian heat extremes. For each approach, methodological details andapplications are provided and limitations highlighted. The conclusions ofthis methodological review discuss the limitations and uncertaintiesassociated with this approach and identify key unexplored applications ofGCM-based attribution of extremes. Ideally, this information will be usefulfor the application of the described extreme event attributionapproaches elsewhere.