Sensitivity of meteorological variables on planetary boundary layer parameterization schemes in the WRF-ARW model

The accuracy of meteorological fields produced by Numerical Weather Prediction (NWP) models are highly dependent on the physical parameterization schemes used. Any errors in simulations of meteorological fields will be passed on to subsequent processes (i.e. air quality models), and will have an effect on their outputs. Therefore, the realistic simulation of meteorological parameters is of utmost importance. The aim of the present research is to evaluate the performance of Planetary Boundary Layer (PBL) schemes contained in the non-hydrostatic Advanced Research Weather Research and Forecasting (WRF-ARW) model when simulating meteorological variables. Four frequently used PBL schemes were investigated by conducting sensitivity experiments during a month in spring and winter in the South African Highveld region for 2016. The simulations resulting from the different schemes were compared against one another, and statistically evaluated by making use of observational meteorological data at five sites. From these results, it is recommended that a local scheme be used for the Highveld region during winter. During spring, the clearly preferred scheme for the Highveld is Mellor-Yamada-Janjic (MYJ) scheme. Results from this study contributes to the establishment of a preferred PBL scheme in the WRF-ARW model, for use in South African Highveld region. Future planned research will considered the effect of the above-mentioned PBL schemes in the simulation of air quality over the same region.