Performance of PALM-4U/WRF model for simulating the urban meteorology of King Abdullah University of Science and Technology (KAUST), Saudi Arabia

This study evaluates the performance of the PALM-4U model nested within the WRF mesoscale model (with and without the chemistry module coupling, WRF-Chem) for simulating air temperature, humidity, and wind speed at 2 m in the semi-urban region of the King Abdullah University of Science and Technology (KAUST), Kingdom of Saudi Arabia (KSA). Microscale simulations were conducted using PALM-4U for two typical days (one day in summer and one day in winter) based on the boundary and initial conditions from WRF and WRF-Chem models for both meteorological and soil parameters. The model's performance was evaluated using measurements available at two weather stations in the study domain. The simulations indicate that PALM-4U performs better when driven by WRF-Chem outputs with global initialization from ERA5 in summer and NCEP-FNL in winter. The results also suggest that PALM-4U performs markedly better than WRF and WRF-Chem in simulating temperature and relative humidity at the KAUST urban scale in both summer and winter based on the overall error metric. Comparison of simulated and observed air temperature at (a) KAUST-1 and (b) KAUST-2 (WRF_F: WRF with NCEP data for initial and boundary condition; WRFC_F: WRF-Chem with NCEP data for initial and boundary condition; Obs: Observation; PALM_F: PALM driven by WRF_F; PALM_C_F: PALM driven by WRFC_F). [Display omitted] •Configuring PALM-4U model for simulating urban climatology of KAUST.•WRF initialization using ERA5 and NCEP-FNL.•Simulation using WRF and WRF-Chem for providing initial/boundary conditions to PALM.•Comparison of simulated meteorological fields with observations.