Numerical Simulation of Land and Sea Breeze (LSB) Circulation along the Guinean Coast of West Africa

Abstract

This study uses observed and simulated data to analyze the dynamics LSB rotation along the Guinean Coast of West Africa. A non-hydrostatic fully compressible numerical model is used to simulate LSB circulation. To evaluate the model’s ability to capture the LSB kinematics, the study used a modified model code with ERA-Interim and CFS as forcing data. Comparison of observed and simulated LSB patterns shows that the model reliably captures the LSB circulation in the region. The simulated diurnal evolutions of hodographs and onshore/offshore winds also follow the observations. A dynamical analysis performed by extracting individual forcing terms from the horizontal momentum equations at selected regions within the study area showed that the direction of the wind rotation is a result of a complex interaction between surface and synoptic pressure gradients, advection, and horizontal and vertical diffusions forces. However, hourly analysis of the rotation term suggests that surface gradient seems to dominate over oceanic region, while diffusion terms are more important for land area. This may be attributed to the variation of surface roughness due the landscape and urbanization. Therefore, this reveals the link between urbanization and LSB circulation in coastal region of West Africa, where most important cities are located.