final_program_abstracts[1]

11 IMSC Session Program
Calibration strategies for inferring future changes in extreme
events from climate simulations
Friday - Parallel Session 7
David B. Stephenson 1 , Chun K. Ho 1 , Mat Collins 1,2 , Chris Ferro 1 and Simon
Brown 2
1
University of Exeter, Exeter, UK
2 Met Office/Hadley Centre, Exeter, UK
The extremal properties simulated by climate models (even the highest resolution
ones) are not expected to be identical to those of observed real world processes. The
numerical models have limited spatial and temporal resolution, missing physical
processes, etc. and so it is not physically unreasonable to expect differences between
simulated extremal properties and those observed in the real world.
This discrepancy needs to be accounted for if one is to use climate change models to
make predictive statements about the behaviour of observable extreme events in the
future. This talk will present various calibration strategies for tackling this problem. It
will be demonstrated that different reasonable calibration strategies yield different
predicted probability distributions.
The strategies will be illustrated using daily summer temperature extremes over
Europe inferred from ensembles of regional climate simulations. The different
approaches will be shown to produce radically different estimates (e.g. 10 year return
values) for future extremely hot days.
Abstracts 341