Cloud Microphysical Characteristics of Typhoon Meranti (2016) during Its Rapid Intensification: Model Validation and SST Sensitivity Experiments

Cloud microphysics plays an important role in determining the intensity and precipitation of tropical cyclones (TCs). In this study, a high-resolution numerical simulation by WRF (version 4.2) of Typhoon Meranti (2016) during its rapid intensification (RI) period was conducted and validated by multi-source observations including Cloud-Sat and Global Precipitation Mission satellite data. The snow and ice particles content were found to increase most rapidly compared with other hydrometeors during the RI process. Not all hydrometeors continued to increase. The graupel content only increased in the initial RI stage, and then decreased afterwards due to precipitation during the RI process. In addition, sea surface temperature (SST) sensitivity experiments showed that, although the intensity of the TC increased with a higher SST, not all hydrometeors increased. The graupel content continued to increase with the increase in SST, mainly due to the accumulation of more lower-temperature supercooled water vapor at the corresponding height. The content of snow decreased with the increase in SST because stronger vertical motion at the corresponding height affected the aggregation of ice crystals.