Sensitivity to Microphysics and PBL Schemes for Extreme Precipitation over the Black Sea Region in Future Climate: Warm and Cold Cases

Detailed information about extreme precipitation is crucial due to the impacts on the human environment. Recently, high-resolution regional climate models (RCMs) are run at convection-permitting scales to investigate the regional precipitation extremes. The Black Sea region is one of the intriguing regions for modelling studies because of its distinctive topographical features where orographic forcing and strong air-sea interactions intensify destructive heavy precipitation. Recently, RCMs have been tested in order to find the most suitable configuration to represent precipitation over this region. Although the historical simulations are beneficial to test the model performance, model configurations may exhibit different spatiotemporal characteristics in simulating extreme precipitation due to the shift of the seasons in a possible warmer future. Recent studies focusing on the intensification of extreme precipitation events highlighted the model sensitivity to increasing sea surface temperature (SST) over the Black Sea. Therefore, future simulations focusing on different model configurations may provide valuable information to understand the response of RCMs in a changing climate. In this study, we downscaled the last generation CMIP6 MPI-ESM1.2-HR outputs by using the WRF model at 3 km horizontal resolution to test the model’s sensitivity for different microphysical and planetary boundary layer (PBL) parameterization options under the SSP5-8.5 future socioeconomic global change scenario. We selected cold and warm extreme precipitation cases and performed 3-days convection-permitting simulations over the complex topography of the Black Sea region. For the cold case, simple single-moment schemes produced less precipitation compared to more complex schemes, especially over the mountains, because of the insufficient representation of snowfall. For the warm case, the difference between the simulations is similar to the cold case but, the magnitude is lower. The change of the PBL scheme affects the vertical and horizontal distribution of microphysical properties and precipitation distribution near the coasts and the mountains.