Evaluation of Weather Research and Forecasting Model Sensitivity to Different Physics Schemes in Convection-Permitting Mode over Southern Iberian Peninsula

Convection-Permitting Models (CPMs) represent a crucial advancement in climate modeling, allowing for enhanced spatial resolution at convection scales (≤ 4 km). In convection-permitting simulations, various small-scale weather processes, notably microphysics and convection, play important roles. Evaluating the Weather Research and Forecasting (WRF) model's performance at convection scales becomes particularly pertinent in complex orography regions with substantial climate variability, such as Andalusia, in the southern part of the Iberian Peninsula (IP). To address this, convection-permitting simulations were conducted, focusing on the assessment of precipitation and 2-m temperature throughout the exceptionally wet year of 2018.

The simulations were based on two "one-way" nested domains: the parent domain (d01) covering the entire IP at 5 km spatial resolution and the nested domain (d02) covering the Andalusia region at 1 km spatial resolution. Implementing these simulations involved the exploration of 12 parameterization schemes, encompassing three microphysics (MP) schemes (THOMPSON, WRF single moment 6-class (WSM6), and WRF single moment 7-class (WSM7)) and four convection schemes for d01 (Grell 3D (G3), Grell-Freitas (GF), Kain-Fritsch (KF), along with the deactivated cumulus parameterization (OFF)). In the process of evaluating the model outputs, a comprehensive approach was adopted, using diverse observational datasets, including both gridded and station data. The comparisons were conducted on a point-to-point basis, considering various time aggregations (monthly, daily and hourly).

Main results show, on one hand, simulations employing the Grell-Freitas (GF) or deactivated cumulus parameterization (OFF) in d01 exhibited superior performance compared to reference datasets. On the other hand, while THOMPSON demonstrated a better fit in high mountain areas, it generally exhibited a poorer agreement with reference datasets than WSM6 and WSM7. In terms of temperature, the results displayed remarkable similarity, prompting the primary consideration of precipitation results. The WSM7-GF scheme emerged as the optimal configuration for the Andalusia region, underscoring its suitability in capturing the complex meteorological dynamics of this distinctive locale.

Keywords: sensitivity study, convection-permitting climate simulations, southern Iberian Peninsula, Andalusia, parameterization schemes, Weather Research and Forecasting model.

 

Acknowledgements:

This research has been carried out in the framework of the projects PID2021-126401OB-I00, funded by MCIN/AEI/10.13039/501100011033/FEDER Una manera de hacer Europa, P20_00035 funded by FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades, and LifeWatch-2019-10-UGR-01 co-funded by the Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014–2020 (POPE) LifeWatch-ERIC action line.