Rainfall is larger over tropical islands than over the surrounding ocean. This has been attributed to the land-sea breeze diurnal cycle and the non-linear effect on precipitation, the so-called "rectification" of the diurnal cycle. We detail this diurnal cycle based on satellite precipitation estimates: a canonical precipitation pattern can be identified in medium-to-large islands, with a propagation of precipitation from the coast inland during the day resulting in large precipitation amounts at the centre of the island. Small and very large islands exhibit different patterns, which we attribute to ventilation for the former and to the limitations on the inland propagation for the latter.

It also appears that the rectification mechanism is not the only one at play in enhancing rainfall over islands. Because surface heat fluxes over land surfaces differ from their counterparts over the ocean, these fluxes have different effects on surface buoyancy and on the energy budget of the atmospheric columns, resulting in increased precipitation over the islands. We also investigate these effects using convection-permitting simulations.