Assessing the performance of WRF ARW model in simulating heavy rainfall events over the Pune region: in support of operational applications

This study evaluates the impact of the Planetary Boundary layer (PBL) on rainfall simulated by the Weather Research and Forecasting (WRF) model during extreme rainfall event cases over an urban city. This is accomplished by producing a heavy rainfall event forecast using the WRF model with five varying PBL scenarios (ACM2, YSU, MYJ, QNSE, MYNN) but otherwise identical model configuration. The study examined the role of PBL in modulating rainfall characteristics by investigating the impacts of PBL on forecast skills with particular reference to rainfall. The PBL scheme plays a crucial role and can significantly alter the spatial pattern and magnitudes of rainfall simulated by the model. Results showed that the QNSE boundary layer scheme substantially improved the magnitudes and spatial pattern of rainfall simulated by the model. The model’s ability was cross-checked with this setup to capture the other two heavy rainfall events over Pune city and was found satisfactory. The current model setup could capture the spatial distribution and the magnitude of rainfall compared with satellite data and observation over point locations. These findings are highly relevant to highlight the dependency of the model on parameterization schemes to forecast extreme rainfall events accurately.