Influence of topography and land-sea contrast on MJO propagation in the Maritime Continent

Understanding the multi-scale interactions between the diurnal cycle in the Maritime Continent (MC) and large-scale circulations remain a challenge. The problem is further exacerbated by the difficulty in simulating the precipitation over the MC, presumably due to error from model physics and resolution that has to deal with the complex topography of the MC. A series of idealized simulations with the Weather Research and Forecasting (WRF) model is conducted to understand the role of topography and land-sea contrast on the propagation of an MJO event. A `Control' simulation captures the spatial distribution of precipitation well including the heavy rainfall areas, although it appears to overestimate over land and underestimate over ocean. The peak amplitude of diurnal precipitation in `Control' simulation is 3 hours earlier than observation over land, but captures the diurnal cycle of precipitation over ocean. The results from a number of idealized topography and land-sea contrasts experiments are discussed along with their implications.