COSMO-CLM regional climate simulations in the Coordinated Regional Climate Downscaling Experiment (CORDEX) framework: a review

Abstract

Abstract. In the last decade, the Climate Limited-area Modeling Community (CLM-Community) has contributed to the Coordinated Regional Climate Downscaling Experiment (CORDEX) with an extensive set of regional climate simulations. Using several versions of the COSMO-CLM-Community model, ERA-Interim reanalysis and eight global climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) were dynamically downscaled with horizontal grid spacings of 0.44∘ (∼ 50 km), 0.22∘ (∼ 25 km), and 0.11∘ (∼ 12 km) over the CORDEX domains Europe, South Asia, East Asia, Australasia, and Africa. This major effort resulted in 80 regional climate simulations publicly available through the Earth System Grid Federation (ESGF) web portals for use in impact studies and climate scenario assessments. Here we review the production of these simulations and assess their results in terms of mean near-surface temperature and precipitation to aid the future design of the COSMO-CLM model simulations. It is found that a domain-specific parameter tuning is beneficial, while increasing horizontal model resolution (from 50 to 25 or 12 km grid spacing) alone does not always improve the performance of the simulation. Moreover, the COSMO-CLM performance depends on the driving data. This is generally more important than the dependence on horizontal resolution, model version, and configuration. Our results emphasize the importance of performing regional climate projections in a coordinated way, where guidance from both the global (GCM) and regional (RCM) climate modeling communities is needed to increase the reliability of the GCM–RCM modeling chain.

Towards Resolving Challenges Associated with Climate Change Modelling in Africa

“…This has led to contradictory conclusions for the same region [52]. Additionally, the computational power and time investment required to run these models is a global issue [53][54][55][56][57] (e.g., CMIP and CORDEX), and can be beyond the reach of many researchers, leading to the necessity of collaboration with international partners. Bias correction [17,58,59] is an additional factor required in validating models; however, the reliability of the output is dependent on the approach employed and the extent of the calibration time, which factors may lead to questionable results, particularly for arid to semi-arid regions.…”

Afforestation impact on soil temperature in regional climate model simulations over Europe

“…The source code of the Weather Research and Forecasting Model (WRF) is available by UCAR/NCAR and can be accessed at https: //www.mmm.ucar.edu/weather-research-and-forecasting-model (Skamarock et al, 2008). The documentation of COSMO-Model is available at the following link (https://www.dwd.de/EN/ ourservices/cosmo_documentation/cosmo_documentation.html, Sørland et al, 2021), although a license is required for access (http://www.cosmo-model.org/content/consortium/licencing.htm, COSMO, 2022). The RegCM4 model is distributed from https://github.com/ictp-esp/RegCM (last access: 8 March 2021; Giorgi et al, 2012).…”

The pseudo-global-warming (PGW) approach: Methodology, software package PGW4ERA5 v1.1, validation and sensitivity analyses

“…Here we assume that such an interpolation module exists with the RCM considered. In the case of the COSMO-CLM model (Rockel et al, 2008;Sørland et al, 2021), the procedure is able to handle two height-based terrain-following hybrid coordinates (Schär et al, 2002;Baldauf et al, 2011). Boundary and initial condition files typically contain much more variables than those modified by the PGW approach.…”