Evaluation of the convection-permitting regional climate model CNRM-AROME41t1 over Northwestern Europe

• Published in: Climate dynamics 2024-06, Vol.62 (6), p.4587-4615
• Main Authors: Lucas-Picher, Philippe, Brisson, E., Caillaud, C., Alias, A., Nabat, P., Lemonsu, A., Poncet, N., Cortés Hernandez, V. E., Michau, Y., Doury, A., Monteiro, D., Somot, S.
• Format: Article
• Language: English
• Subjects: Annual cycles; Annual precipitation; Annual variations; Climate; Climate models; Climatology; Cloud cover; Convection; Datasets; Diurnal cycle; Diurnal variations; Earth and Environmental Science; Earth Sciences; Evaluation; Extreme values; Extreme weather; Geophysics/Geodesy; Ocean, Atmosphere; Oceanography; Orography; Precipitation; Radiation-cloud interactions; Regional climate models; Regional climates; Regional development; Sciences of the Universe; Short wave radiation; Simulation; Snow cover; Surface temperature
• ISSN: 0930-7575; 1432-0894
• DOI: 10.1007/s00382-022-06637-y

Since a decade, convection-permitting regional climate models (CPRCM) have emerged showing promising results, especially in improving the simulation of precipitation extremes. In this article, the CPRCM CNRM-AROME developed at the Centre National de Recherches Météorologiques (CNRM) since a few years is described and evaluated using a 2.5-km 19-year long hindcast simulation over a large northwestern European domain using different observations through an added-value analysis in which a comparison with its driving 12-km RCM CNRM-ALADIN is performed. The evaluation is challenging due to the lack of high-quality observations at both high temporal and spatial resolutions. Thus, a high spatio-temporal observed gridded precipitation dataset was built from the collection of seven national datasets that helped the identification of added value in CNRM-AROME. The evaluation is based on a series of standard climatic features that include long-term means and mean annual cycles of precipitation and near-surface temperature where CNRM-AROME shows little improvements compared to CNRM-ALADIN. Additional indicators such as the summer diurnal cycle and indices of extreme precipitation show, on the contrary, a more realistic behaviour of the CNRM-AROME model. Moreover, the analysis of snow cover shows a clear added-value in the CNRM-AROME simulation, principally due to the improved description of the orography with the CPRCM high resolution. Additional analyses include the evaluation of incoming shortwave radiation, and cloud cover using satellite estimates. Overall, despite some systematic biases, the evaluation indicates that CNRM-AROME is a suitable CPRCM that is superior in many aspects to the RCM CNRM-ALADIN.