## Imposing land-surface fluxes at an immersed boundary for improved simulations of atmospheric flow over complex terrain

Boundary layer flows are greatly complicated by the presence of complex terrain which redirects mean flow and alters the structure of turbulence. Surface fluxes of heat and moisture provide additional forcing which induce secondary flows, or can dominate flow dynamics in cases with weak mean flows. Mesoscale models are increasingly being used for numerical simulations of boundary layer flows over complex terrain. These models typically use a terrain-following coordinate transformation, but these introduce numerical errors over steep terrain. An alternative is to use an immersed boundary method which alleviates errors associated with the coordinate transformation by allowing the terrain tomore »