The surface processes of the Rossby Centreregional atmospheric climate model (RCA4)

Type: Report
Series: Meteorology 157
Author: Patrick Samuelsson1, Stefan Gollvik1, Christer Jansson1, Marco Kupiainen1, Ekaterina Kourzeneva2, Willem Jan van de Berg3 1 Swedish Meteorological and Hydrological Institute, (SMHI), Norrköping, Sweden 2 Finnish Meteorological Institute, (FMI), Helsinki, Finland 3 Institute for Marine and Atmospheric research Utrecht University, (IMAU), the Netherlands


This report describes the physical processes as part of the surface scheme in the Rossby Centre Regional Atmospheric Climate Model (RCA4). Or more strictly for the version used for the CORDEX downscalings with RCA4.

The most important aspects of the surface scheme that are changed with respect to RCA3 are that (i) a new physiography data base is used, (ii) the number of soil layers with respect to soil moisture are increased from two to three and there is also separate soil columns with respect to soil water under forest and open land, respectively, (iii) an exponential root distribution is used, (iv) the density of organic carbon is used to modify soil properties, (v) the prognostic snow albedo is modified to perform better in cold-climate conditions, (vi) Flake is introduced as lake model and lake depth is defined from a global lake-depth data base, (vii) the dynamic vegetation model LPJ-GUESS is introduced for vegetation-climate feedback studies.