Effects of cloud microphysics on monsoon convection and its environments over the South China Sea: A two-dimensional cloud-resolving modeling stud

The Weather Research Forecast (WRF) model imposed by the large-scale advective forcing derived from observed data representing an average of gridded data fields over the South China Sea Monsoon Experiment (SCSMEX) was used to study the effects of cloud microphysics on monsoon convective systems and its formation environment over the tropical ocean. The temporal variation of the WRF model-simulated rain rate is in good agreement with the observed data.

The sensitivity experiments with ice runs and ice-free runs show that the ice run can produce less rain prior to and during the onset of the monsoon period: the mean decrease can be −5 mm d−1 and the maximum decrease can be more than 60 mm d−1 during the post onset of the monsoon period, and about 6% decrease of the domain-averaged accumulative rainfall. The mechanism that induces this phenomenon was investigated through the budget of cloud radiation forcing, the variations of latent heating and cooling, and that of terminal fall velocities of cloud hydrometeors due to phase change in this paper, and show that at the top of atmosphere the net cloud radiation forcing on both ice cloud and water cloud can be neglected.