Improving Supercooled Water Forecast Through Real‐Time Aerosol Input: A Case Study

Abstract

Accurately simulating and forecasting supercooled water has been crucial for addressing the threat of aircraft icing. This study utilized the Weather Research and Forecast model and Aerosol‐Aware Thompson‐Eidhammer microphysics (TE14) scheme to simulate supercooled water properties. Three high‐resolution experiments were conducted to explore the impact of increased model resolution and different aerosol initial conditions. The synoptic‐scale characteristics and cloud extent were well‐matched between observations and the model simulation, which established a background for supercooled water comparisons. Microphysical characteristics of supercooled droplets and the formation of supercooled large drops demonstrated the TE14 scheme's reasonable simulation of supercooled water microphysics under different aerosol loadings. In situ aircraft measurements were used to validate the simulated supercooled water properties. Results highlighted the sensitivity of supercooled water simulation to aerosol number concentration via droplet activation in the scheme. The choice for the aerosol initial condition could result in a significant underestimation or overestimation of supercooled water number concentration, consequently leading to biased estimations of droplet size. Incorporating real‐time forecast aerosol data improved the simulation by increasing cloud droplet number concentration and reducing droplet size. These findings underscored the importance of aerosols via droplet activation in accurately simulating cloud water properties and emphasized their role in forecasting aircraft icing hazards.