Mechanistic Impacts of a Scale-Aware Convection Scheme on Typhoon Intensity: Diagnostics From Minimum Sea-Level Pressure

This study investigates the impact of a scale-aware convective parameterization scheme (CPS) on the simulation of typhoon track and intensity through a series of experiments using the Global-to-Regional Integrated Forecast SysTem (GRIST) model. The results of four typhoon cases show the scale-aware CPS generally reduces the track error by about 15 km and the intensity error by about 10% compared to the default CPS. By analyzing the budget equation of surface pressure tendency, we found the surface pressure fall due to CPS heating is about 0.6 hPa h⁻¹ weaker when the scale-aware CPS is used. This is, however, compensated by enhanced microphysics heating, which more than offsets the reduction in CPS and yields a net pressure depression of about 1 hPa h⁻¹. In fact, when parameterized convection is suppressed, the microphysics process takes up the convective instability left over by CPS and stimulates even stronger diabatic heating by 13.8%. The increased microphysics precipitation, along with the intensified grid-scale ascending, further validates the assertion. The results of this study demonstrate the benefits of scale-aware CPS on typhoon modeling.