SCALMET (Scaling meteorological variables) has been developed by Marke (2008) as a FORTRAN-based model coupler that is performing a synchronized exchange of hydrometeorological data between models for the atmosphere and the land surface. As climate models are still computationally limited to relatively coarse spatial resolutions of at best 10 x 10 km, adequate techniques have been implemented for the downscaling and upscaling of model calculations.
Topography of the Upper Danube Watershed (Central Europe) in different spatial resolutions.
The coupler includes the following scaling techniques:
- Inverse distance weighted, bilinear and conservative interpolation (Jones 1998)
- Quasi physically based downscaling (Liston and Elder 2006; Cosgrove et al. 2003; Thornton et al. 1997)
- Statistical downscaling with option for bias correction (Früh et al. 2006; Marke et al. 2011)
Independently from the scaling algorithm applied, mass and energy between the model scales can optionally be conserved in order to prevent model drift within the coupled model system.
SCALMET has proven to be robust under a variety of climatological and hydrological conditions and has already been sucessfully applied in various regions of the world (e.g., Upper Danube watershed in central Europe, upper Brahmaputra watershed in Asia). Besides these applications in one-way coupled model systems (climate model –> land surface model) the coupler has recently been set up in a two-way coupled mode (climate model –> land surface model –> climate model).
Overview of the coupled land-atmosphere model system.
SCALMET key publications:
Marke, T., Mauser, W., Pfeiffer, A., Zängl, G. and Jacob, D. (2011): The effect of downscaling on river runoff modeling: A hydrological case study in the Upper Danube Watershed, Hydrol. Earth Syst. Sci. Discuss., 8, 6331–6384.
Zabel, F., Mauser, W., Marke, T., Pfeiffer, A., Zängl, G. and Wastl. C. (2011): Inter-comparison of two land-surface schemes applied on different scales and their feedbacks while coupled with a regional climate model, Hydrol. Earth Syst. Sci. Discuss., 8, 7091–7136.
Marke, T., Mauser, W., Pfeiffer, A. and Zängl, G. (2011): A pragmatic approach for the downscaling and bias correction of regional climate simulations: evaluation in hydrological modeling, Geosci. Model Dev., 4, 759–770.
Marke, T. (2008): Development and Application of a Model Interface to couple Regional Climate Models with Land Surface Models for Climate Change Risk Assessment in the Upper Danube Watershed, Dissertation der Fakultät für Geowissenschaften, Digitale Hochschulschriften der LMU München, 188, München.