Concerning “Global Climate Change” it is of special importance how far
particular properties of extreme events will change during the next decades.
Extreme precipitation is a prominent example. For individual regions there
might be small-scale varieties, which can only be derived by indirect
means from large-scale GCM output (General Circulation Models, grid point
distances several hundred km). In that respect, deriving regional precipitation
from large-scale GCM data (so-called downscaling) has to be critically
assessed, since relationships between regional precipitation (spatial
scale of Central Europe or smaller areas) and ‘Großwetterlage’ (i.e.
pressure fields on a continental scale) are marked by considerable instationarities.
Consequently and in contrast to that, analysing fronts and convective
conditions of regional to local dimensions is the starting point of this
project. A fundamental advantage could be that fronts and convective phenomena
cover areas comparable in extent to those being affected by resulting
precipitation and runoff. Based on that, output of the atmosphere-ocean
GCM ECHAM4 (Hamburg) can be used for more consistent estimations of 21st
century’s precipitation variability.
Scientists