Sensitivity of Typhoon Simulation to Physics Parameterizations in the Global Model

Abstract

The sensitivity of the typhoon track and intensity simulation to physics schemes of the global model are examined for the typhoon Bolaven and Tembin cases by using the Global/ Regional Integrated Model System-Global Model Program (GRIMs-GMP) with the physics package version 2.0 of the Korea Institute of Atmospheric Prediction Systems. Microphysics, Cloudiness, and Planetary boundary Layer (PBL) parameterizations are changed and the impact of each scheme change to typhoon simulation is compared with the control simulation and observation. It is found that change of microphysics scheme from WRF Single-Moment 5-class (WSM5) to 1-class (WSM1) affects to the typhoon simulation significantly, showing the intensified typhoon activity and increased precipitation amount, while the effect of the prognostic cloudiness and PBL enhanced mixing scheme is not noticeable. It appears that WSM1 simulates relatively unstable and drier atmospheric structure than WSM5, which is induced by the latent heat change and the associated radiative effect due to not considering ice cloud. And WSM1 results the enhanced typhoon intensity and heavy rainfall simulation. It suggests that the microphysics is important to improve the capability for typhoon simulation of a global model and to increase the predictability of medium range forecast.

Sensitivity of Precipitation and Structure of Typhoon Hato to Bulk and Explicit Spectral Bin Microphysics Schemes

“…Analysis of microphysical processes to investigate the sensitivities of typhoons or precipitation to different factors has become increasingly popular in recent years. Considerable research has been undertaken to verify and improve the efficacy of microphysical schemes through comparison and analysis of the effects of different schemes on the typhoon structure or precipitation [23][24][25][26][27][28]. For example, some sensitivity analyses have been undertaken to identify the optimal combination of microphysical and convective schemes [29].…”