Learning by doing: seasonal and diurnal features of tropical
precipitation in a global-coupled storm-resolving model
Abstract
Using the global and coupled ICON-Sapphire model with a grid spacing of
\SI{5}{\kilo\meter}, we
describe seasonal and diurnal features of the tropical rainbelt and
assess the limits of ICON-Sapphire in representing tropical
precipitation. Aside from the meridional migration, the tropical
rainbelt exhibits a seasonal enlargement and a zonal migration.
Surprisingly, ICON-Sapphire reproduces these characteristics with better
performance over land than over ocean and with a very high degree of
agreement to observations. ICON-Sapphire especially struggles in
capturing the seasonal features of the tropical rainbelt over the oceans
of the Eastern Hemisphere, an issue associated with a cold SST bias at
the equator. ICON-Sapphire also shows that a perfect representation of
the diurnal cycle of precipitation over land is not a requirement to
capture the seasonal features of the rainbelt over land, while over the
ocean, 5km is sufficient to adequately represent the diurnal cycle of
precipitation.