Diurnal cycle of rainfall and winds near the south coast of China

Both the CMORPH and Du model data indicate that the diurnal cycle of rainfall has two propagation modes near the coast: onshore and offshore. The diurnally periodic winds (vertical motions) also show a similar propagation feature.

Analysis of the rainfall budget indicates that vertically integrated vertical vapor advection plays a key role in the diurnal cycle of rainfall and thus provides a physical connection between winds and rainfall in the diurnal cycle. It was found that a simple 2D linear land-sea breeze model with a background wind can well capture the two propagation modes, which are associated with inertia-gravity waves, in terms of speed and phase.