Sensitivity of Fine-Scale Structure in Tropical Cyclone Boundary Layer to Model Horizontal Resolution at Sub-Kilometer Grid Spacing

In view of the increasing interest in explicit simulation fine-scale features tropical cyclone (TC) boundary layer (TCBL), effects horizontal grid spacing on a 7–10 h an idealized TC are examined using Weather Research and Forecast (ARW-WRF) mesoscale model with one-way moving nests nonlinear backscatter anisotropy (NBA) sub-grid-scale (SGS) scheme. general, reducing from 2 km to 500 m tends produce stronger lower minimum sea level pressure (MSLP), surface winds, smaller inner core size. However, large eddies cannot be resolved at these spacings. contrast, 166 further 55 leads decrease intensity increase inner-core Moreover, although 166-m starts resolve terms TCBL rolls tornado-scale vortex, use finest shorter wavelengths turbulent motion multi-scale turbulence interaction. It is concluded that sub-100-meters desirable more detailed structure vortices, while relatively coarse sub-kilometer (e.g., m) cost-effective feasible for research not interested processes real-time operational forecasting near future.