|NHCM-1 - Non hydrostatic climate modeling
|Andreas Gobiet (Uni Graz)
Nauman Khurshid Awan (PhD Student: Dynamical Downscaling)
|Bodo Ahrens (Institut für Atmosphäre und Umwelt, Frankfurt)
Daniela Jacob, Stefan Hagemann (Max Planck Institute for Meteorology, Hamburg)
Klaus Keuler (Chair of environmental meteorology, BTU Cottbus)
Xin-Zhong Liang (Illinois State Water Survey, UIUC)
Axel Seifert (German Weather Service)
|FWF Austrian Science Fund (P19619)
|Mar. 2007 - Feb. 2010
Those characteristics of climate which have direct impact on human society and ecosystems are often related to small scale phenomena. In this context, particularly hydrological features and extreme climate events are of highest relevance and considerable demand for highly resolved climate analyses and projections exists on the part of climate impact research. Current regional climate models are generally operated at 20–50 km horizontal grid resolution, a scale where many regional features can be well resolved but too coarse for proper representation of important features such as severe precipitation events and their spatial distribution or diurnal cycle of precipitation, particularly over complex terrain.
Climate simulations on finer, local scales (grid spacing less than 10 km) are conceptually very promising to resolve or at least mitigate these problems, but many methodological challenges hamper the reliable application of local scale climate models (LCMs), such as shortcomings in physical parameterisations also in climate models principally capable to resolve local scales (non-hydrostatic climate models, NHCMs). Significant obstacles exist also to adequate spatial validation of high-resolution model results due to poor availability of suitably dense observations. Up to date, the uncertainty range of LCM simulations has thus not been systematically investigated.
In the framework of the proposed project Non-Hydrostatic Climate Modelling (NHCM-1), systematic sensitivity studies will be conducted with focus on two test areas in Austria (an alpine region ”Hohe Tauern“ and a hilly area ”Oststeiermark“) at 10 km, 3 km, and 1 km horizontal grid resolution with two LCMs (German CLM and U.S. MM5 model) aiming at elucidating the resolution-dependant performance of various model components, particularly physical parameterisation. In its investigations in one of the test areas, the project will be backed by a novel, high-resolution dataset from 150 climate stations (“WegenerNet”) available for model evaluation purposes. As part of the project, an international intercomparison campaign for LCMs will be conducted. This will enable for the first time to quantitatively investigate the uncertainty range associated with LCMs using probabilistic techniques.
The overall goal of the project is to examine yet unclear potentials and shortcomings of current LCMs and to provide estimates on uncertainties related to these highly relevant tools. The broader and longer-term background aim is to build a better basis for LCM development and of providing climate impact research with more suitable, more reliable, more comprehensive, and more consistent data than available today.