Abstract:The two time level semi Lagrangian advection scheme is designed to study the process of global advection based on the the spherical overset Yin Yang grid. A kind of new horizontal staggered grid named LE grid is adopted for the scheme in the spherical coordinate, and different interpolation methods have been employed to the overlapped area of the Yin Yang grid. Besides, some idealized numerical tests are carried out. Numerical tests show that the scheme is reasonable for simulating the global advection, the advection of the overset area is obviously sensitive to the boundary interpolation schemes; the semi Lagrangian scheme can depict the structure, position and the evolution process of solid body and deformational vortex accurately, and can get good stability and high accuracy.