Resolved Convection Improves the Representation of Equatorial Waves and Tropical Rainfall Variability in a Global Nonhydrostatic Model

Numerical weather and climate models continue to struggle with simulating equatorial waves and tropical rainfall variability. This study presents a potential remedy—high-resolution global models with explicitly resolved convection. A series of global nonhydrostatic simulations was produced with horizontal cell spacings between 3.75 and 480 km; the share of resolved precipitation in these simulations ranged from 88% to 2%. The simulations in which convection was mostly resolved produced much more realistic equatorial waves than the simulations in which convection was mostly parameterized. Consequently, the simulations with resolved convection produced more realistic precipitation patterns and precipitation variances. The results demonstrate that high-resolution global models with explicitly resolved convection are a promising tool to improve tropical weather forecasts and climate projections.