Tropical cyclones and equatorial waves in a convection-permitting aquaplanet simulation with off-equatorial SST maximum

This study introduces a convection-permitting aquaplanet simulation that can be used as a laboratory to study TCs, equatorial waves, and their interactions. The simulation was produced with the Model for Prediction Across Scales-Atmosphere (MPAS-A) using a variable resolution mesh with convection-permitting resolution (i.e., 3-km cell spacing) between 10 degrees S and 30 degrees N. The underlying sea-surface temperature is given by a zonally symmetric profile with a peak at 10 degrees N, which allows for the formation of TCs.

A comparison between the simulation and satellite, reanalysis, and airborne dropsonde data is presented to determine the realism of the simulated phenomena. The simulation captures a realistic TC intensity distribution, including major hurricanes, but their lifetime maximum intensities may be limited by the stronger vertical wind shear in the simulation compared to the observed tropical Pacific region. The simulation also captures convectively coupled equatorial waves, including Kelvin waves and easterly waves.