final_program_abstracts[1]

11 IMSC Session Program
European extra-tropical storm damage risk from a highresolution
multi-model ensemble of dynamically downscaled
global climate models
Thursday - Parallel Session 7
Malcolm R. Haylock
PartnerRe Reinsurance Company, Zurich, Switzerland
A set of European wind storms was derived from twenty-two 25km regional climate
model runs driven by either the ERA40 reanalyses or one of four coupled atmosphereocean
global climate models. Storms were identified using a model-dependent storm
severity index based on maximum daily 10m sustained wind. We calibrated the storm
set of each model to a set of high resolution 7km historical storm windfields using the
70 storms with the highest severity index in the period 1961-2000, employing a two
stage calibration methodology. First we downscaled the 25km daily maximum
sustained to our 7km historical model grid using the 7km surface roughness and
elevation, also applying an empirical gust parameterisation. Secondly we statistically
calibrated wind speeds to our historical storms to match the geographically-dependent
cumulative density distribution.
The greatest downscaling challenges were to produce a storm set from each 25km
model that showed similar statistical properties to the historical sets, in particular
similar intensity attenuation across the set, and to combine the 22 individual models
into a single homogenous millennium-scale storm set.
The final combined historical-regional model event set of storms was run through an
operational catastrophe reinsurance pricing model to determine the return level of loss
to a Europe-wide population derived portfolio of residential property. The model
showed close agreement between the combined storm set and the historical storm set
with the added benefit of more detail at higher return periods.
Abstracts 253