Numerical study of the impact of differences between sea and land underlying surface on thunderstorm in the Ningbo area

The thunderstorm process is simulated by the WRF model coupled with the Noah land-surface model. In this paper, the impact of sea-land underlying surface on thunderstorm is studied by changing the land cover type of underlying surface. The results show that the development process of thunderstorm is successfully captured by the WRF model. Before the thunderstorm takes place, since thermal contrast between the sea surface and the land surface is so strong that there is a distinct sea breeze circulation caused. Then the thunderstorm is triggered by lifting movement. The strong surface convergence is coinciding with the accumulated precipitation core produced by the thunderstorm. When water is replaced with land, uplifting movement become stronger in the east part of the study area for the increased land surface roughness. Several powerful convective cells form in the east part of the uplifting area, which expanded the rain area, increased the accumulated rainfall and extended the duration of the thunderstorm. When land is replaced with water, surface fluxes decrease in the daytime and turbulent motion becomes weak. So boundary layer becomes low, the atmospheric stratification turns to being stable and the thunderstorm is not easy to develop.