ICON in Climate Limited-area Mode (ICON Release Version 2.6.1): a new regional climate model

Abstract

<jats:p>Abstract. For the first time the limited-area mode of the new weather and climate model ICON has been used for a continuous long-term regional climate simulation over Europe. Building upon ICON-LAM, ICON-CLM v.0 (ICON in Climate Limited-area Mode, hereafter ICON-CLM) is an adaptation for climate applications. A first version of ICON-CLM is now available and has already been integrated into a starter package (ICON-CLM_SP). The starter package provides users with a technical infrastructure that facilitates long-term simulations as well as model evaluation and test routines. ICON-CLM and ICON-CLM_SP were successfully installed and tested on two different computing systems. Test with different domain decompositions showed bit-identical results, and no systematic outstanding differences were found in the results with different model time steps. Comparison was done between ICON-CLM and COSMO-CLM (the recommended model configuration by the CLM-Community) performance. For that, an evaluation run with ERA-Interim boundary conditions was carried out with the setups similar to the COSMO-CLM recommended optimal setups. ICON-CLM results showed biases in the same range as those of COSMO-CLM for all evaluated surface variables. This is remarkable because the COSMO-CLM simulation was carried out with the latest model version which has been developed for two decades and was carefully tuned for climate simulations on the European domain. Furthermore, ICON-CLM already showed a better performance for air temperature, its daily extremes, and total cloud cover. Results for precipitation and mean sea level pressure did not show clear advantage from any model. However, as ICON-CLM is still in the early stage of development, there is still much room for improvement. </jats:p>

Impact of Urban Canopy Parameters on a Megacity’s Modelled Thermal Environment

“…Recently, the TERRA_URB scheme was implemented to a newer version of COSMO (5.05urb, used in the current study) as part of the AEVUS (Analysis and evaluation of the TERRA_URB scheme) priority task of the COSMO consortium [6,50]. This newer version includes improved boundary-layer physics and is unified with the recent developments of the ICON (ICOsahedral Nonhydrostatic) modelling system [51,52]. In the near future, TERRA_URB is planned to be implemented to the major branch of COSMO (version 6.0) and ICON.…”

“…Continental LCZ maps already exist for Europe [28] and the continental United States [26,94], both paving the way for global coverage. Such advancement is especially important for the ICON model, which will replace the COSMO model in COSMO NWP consortium and CLM-Community as a seamless tool for global and limited-area applications [51,52]. The ICON model does not include any UCM yet, however there are plans to transfer the TERRA_URB scheme from COSMO to ICON in a near future.…”

Systematic Calibration of a Convection‐Resolving Model: Application Over Tropical Atlantic

“…It is thus attractive to consider a combined GCM/RCM calibration framework, that considers both approaches. Indeed, there is an increasing number of GCMs that are available in both limited‐area and global configurations, such as the ICON model (Pham et al., 2021) or the Unified Model (Bush et al., 2020). With such models, it is feasible to combine RCM‐style calibrations in subdomains.…”

Regional Climate Modelling with COSMO-CLM: History and Perspectives

“…However, since the COSMO model will not be developed any further, and the support of COSMO and DWD for the model will be stopped, members of the CLM-Community already started to develop a regional climate mode of ICON several years ago. A first version of ICON-CLM (ICON Climate Limited-area Mode) was prepared in 2019 and a reference simulation showed that ICON-CLM already performs as well as COSMO in many aspects and is computationally more efficient [7]. However, there are still many technical developments necessary until the new modelling system will have the same functionality as COSMO-CLM today.…”