Comparison of Three Cloud Microphysical Schemes on the Rapid Intensification of Typhoon Hagupit (2020)

A typhoon Hagupit (2020) that intensifies rapidly near the coast is simulated by using the Weather Research and Forecasting (WRF V4.2.1) model. The typhoon track, intensification, and precipitation simulated by WSM6, Morrison, and Goddard 4-ice cloud microphysics schemes were evaluated based on observations. The simulation biases during the typhoon’s Rapid intensification process were analyzed. The results showed that all three schemes effectively simulated the typhoon's track and precipitation, but their simulations of intensity varied significantly. The Morrison scheme better reproduced the typhoon's intensity, whereas WSM6 underestimated it and Goddard 4-ice overestimated it. Differences in the simulated typhoon intensity corresponded well with variations in the mass mixing ratio of ice-phase particles. During the intensification process, Goddard 4-ice exhibited the highest rate of ice particle formation through vapor deposition, while WSM6 had the lowest. Sensitivity experiments further demonstrated that latent heat release from the deposition of ice-phase particles warmed the air, which enhanced the typhoon's warm-core structure and strengthened the upward outflow in the eyewall. This process accelerated the inflow of low-level air toward the typhoon center, increasing the pressure gradient and maintaining the extremely low central pressure. This study proposes that the process of ice-phase hydrometeor deposition plays a critical role in simulating typhoon rapid intensification.