Simulations with the KNMI regional climate model RACMO2 in contribution to CORDEX
Abstract
The KNMI regional climate model RACMO2 is used for the regional downscaling of IPCC climate change scenarios with a focus on aspects of the hydrological cycle. In this paper we discuss results from present-day climate as well as transient climate simulations with RACMO2 for the CORDEX regions Africa (50km resolved), Antarctica (50km) and Europe (50 and 12km). The present-day climate simulations, referred to as the evaluation run, are forced with ERA-Interim re-analyses for the period 1979-2010. The climate change scenario calculations are forced with a realization of EC-EARTH2.3 (r1i1p1), utilizing historic GHG concentrations and aerosol loadings for the period 1950-2005, and assuming the RCP4.5 and RCP8.5 scenarios for the period 2006-2100. The baseline version of RACMO2 carries the package of physical parameterizations from the ECMWF model cycle 31r1 which is very similar to what is used in ERA-Interim and EC-EARTH. For the simulation of Antarctic conditions the model is equipped with an advanced multi-layer snow-refreezing module, a snow drift module and a snow grain size-albedo feedback module. For the simulations of Africa and Europe the hydrological component of the surface/soil scheme is adopted from HTESSEL (ECMWF cycle33r1) to account for spatial heterogeneity in soil hydraulic parameters. For the simulation of CORDEX-Africa the surface albedo is inferred from MODIS maps, allowing a much better estimate of 2-meter temperature patterns across the Sahara desert. For the simulation of CORDEX-Europe (instead of surface albedo) the leaf-area index is inferred from MODIS maps, permitting a much better seasonal forcing associated to this parameter. In addition to the Europe integration, the boundary-layer scheme was extended with a TKE-closure to better represent the diurnal evolution of boundary-layer clouds. Assessment of the simulations will focus on precipitation patterns and changes therein (Africa simulation), the temporal structure of the surface mass balance and its components (Antarctica simulation), and precipitation extremes at sub-daily time scales (Europe simulation).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.A32E..06V
- Keywords:
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- 3355 ATMOSPHERIC PROCESSES / Regional modeling