Simulations of the Lunar Exosphere: Initial Conditions of atomic species near the Surface of the Moon

It is interesting to find the best exospheric model that can account for the observed characteristics of the lunar coma and tail simultaneously. Recently, the initial abundances of atomic species near surface are found to be different depending on certain local areas. We will present the influence of different initial conditions of localized sources on the characteristics of the lunar exosphere, and also present time-dependent simulations showing the distributions of atomic species around the lunar coma and the final stage of the lunar tail. Based on our updated 3-D lunar model, we will present resulted physical parameters of the lunar sodium coma and tail.