Impacts of cloud radiative processes on the convective and stratiform rainfall associated with Typhoon Fitow (2013)

The three-dimensional Weather Research and Forecasting (WRF) model was used to conduct sensitivity experiments during the landfall of Typhoon Fitow (2013) to examine the impacts of cloud radiative processes on thermal balance. The vertical profiles of heat budgets, vertical velocity, and stability were analyzed to examine the physical processes responsible for cloud radiative effects on surface rainfall for Typhoon Fitow (2013). The inclusion of clouds reduced radiative cooling in ice and liquid cloud layers by reducing outgoing radiation. The suppressed radiative cooling reduced from the ice cloud layers to liquid cloud layers. This was conducive to reducing instability. The decreased instability was associated with the reduced upward motions. The reduced upward motion led to a decreased vertical mass convergence. Consequently, heat divergence was weakened to warm the atmosphere. Together with suppressed radiative cooling, these effects jointly suppressed net condensation and rainfall. Furthermore, the reduced rainfall due to the cloud radiative effects were mainly associated with the reduced convective and stratiform rainfall. The reduced convective rainfall was associated with the reduced net condensation, while the reduced stratiform rainfall was related to the constraint of hydrometeor convergence.