final_program_abstracts[1]

11 IMSC Session Program
The limits of pattern scaling
Friday - Poster Session 7
Andreas Lustenberger and Reto Knutti
Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland
For the assessment of future climate scenarios and the associated impacts, it is
important to have reliable projections based on future emission scenarios. However,
for an appropriate statistic there are more scenarios necessary than can be simulated
by a global climate model (GCM) or regional climate model (RCM). Additional
scenarios may be generated by scaling a response pattern simulated by a GCM or
RCM. We investigate the limits of scaling temperature and precipitation patterns
using different statistical approaches for the pattern scaling. The pattern scaling
technique will be applied to the 27 extreme indices suggested by the joint
CCI/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices
(ETCCDI). The different statistical approaches will be developed and tested with the
aid of the recent RCM transient runs of the ENSEMBLES project covering the time
period from 1950 to 2100. The areas of interest are Switzerland and Europe. The
higher spatial resolution of the RCMs is often associated with the presence of more
nonlinear processes. In addition, extremes also exhibit nonlinear behaviour.
Therefore, this project investigates the inuences of the potential nonlinearity on the
pattern scaling and attempts to answer the question if the pattern scaling technique is a
reasonable method for the development of scenarios of extreme events. Especially in
case of scaling precipitation patterns, it is expected that the use of predictors other
than temperature should increase the accuracy of a scaled pattern. Effects of a
complex topography and site-specific conditions on the scaling of RCM response
patterns may also lead to a spatially dependent scaling.
Abstracts 314