Evaluation of different microphysical schemes for simulating a complex aircraft icing case

To improve the numerical simulation of supercooled water and Supercooled Large Droplets (SLD) for aircraft icing forecasting, this study evaluates four microphysical schemes (Thompson, Morrison, NSSL, P3) in the Weather Research and Forecasting (WRF) model for a complex icing case in Henan, China, on 10 December 2018. This event featured supercooled small droplets, SLD, and mixed-phase conditions. Simulations were evaluated against in-situ aircraft data. All schemes reasonably captured the precipitation pattern and the cloud-phase transition from liquid to ice. They also identified regions of high icing potential (>75%) and severe icing along the flight track. However, significant differences emerged in simulating liquid/ice water paths and key microphysical parameters like droplet number and mass concentration, and Median Volume Diameter (MVD). These differences affected the forecast of SLD location. The NSSL scheme performed best for supercooled small droplets, while both NSSL and P3 schemes reproduced SLD well. Overall, the NSSL scheme provided the best balance in simulating icing potential, SLD presence, and severity, with its simulated SLD distribution showing the closest agreement with aircraft observations. This study highlights the critical impact of microphysical scheme choice on icing forecasts and provides guidance for selecting appropriate schemes in operational aviation weather forecasting.