| Abstract: | The accurate forecasting of tropical cyclones (TCs) is a challenging task. The purpose of this study was to investigate the effects of a dry-mass conserving (DMC) hydrostatic global spectral dynamical core on TC simulation. Experiments were conducted with DMC and total (moist) mass conserving (TMC) dynamical cores. The TC forecast performance was first evaluated considering 20 TCs in the West Pacific region observed during the 2020 typhoon season. The impacts of the DMC dynamical core on forecasts of individual TCs were then estimated. The DMC dynamical core improved both the track and intensity forecasts, and the TC intensity forecast improvement was much greater than the TC track forecast improvement. Sensitivity simulations indicated that the DMC dynamical core-simulated TC intensity was stronger regardless of the forecast lead time. In the DMC dynamical core experiments, three-dimensional winds and warm and moist cores were consistently enhanced with the TC intensity. Drier air in the boundary inflow layer was found in the DMC dynamical core experiments at the early simulation times. Water vapor mixing ratio budget analysis indicated that this mainly depended on the simulated vertical velocity. Higher updraft above the boundary layer yielded a drier boundary layer, resulting in surface latent heat flux (SLHF) enhancement, the major energy source of TC intensification. The higher DMC dynamical core-simulated updraft in the inner core caused a higher net surface rain rate, producing higher net internal atmospheric diabatic heating and increasing the TC intensity. These results indicate that the stronger DMC dynamical core-simulated TCs are mainly related to the higher DMC vertical velocity. |
