Impact of Convective Momentum Transport by Deep Convection on Simulation of Tropical Intraseasonal Oscillation

This paper focuses on the impacts of convective momentum transport (CMT) on simulations of the tropical intraseasonal oscillation (TIO) in SAMIL. Two sets of experiments are performed, which give different reality of the Madden-Julian Oscillation (MJO). The Tiedtke cumulus parameterization scheme is used for all experiments. It is found that simulations of the TIO can be influenced by CMT, and the impacts on the simulated TIO depend on the model capability in simulating the MJO. CMT tends to have large influences to the model that can simulate the eastward propagation of the MJO. CMT can further influence the long-term mean of zonal wind and its vertical shear. Zonal wind suffers from easterlies biases at low level and westerlies biases at upper level when CMT is introduced. Such easterlies biases at low level reduce the reality of the simulated tropical intraseasonal oscillation. When CMT is introduced in the model, MJO signals disappear but the model's mean state improves. Therefore, a more appropriate way is needed to introduce CMT to the model to balance the simulated mean state and TIO signals.