资源环境科技发展态势分析平台

The evolution of landfalling Typhoon Fitow in the western North Pacific in 2013 is simulated with an emphasis on the direct radiative effect of sea-salt aerosols (SSAs) on the precipitation of Fitow. The inhomogeneous SSAs, formed under the environment with low relative humidity (50%-70%), exhibit different optical properties (particular the decreased asymmetry factor) compared with the commonly used homogeneous sea-salt droplets. We find that incorporating the inhomogeneity of SSAs in the Weather Research and Forecasting (WRF) model decreases the simulated rainfall of Fitow in coastal regions where the continental dry air intrudes. Fundamentally, the cooling effect induced by the particle inhomogeneity and its hysteresis increase atmospheric stability and weaken vertical velocity, which reduce the accumulated rainfall of Fitow. These findings of radiation-related effects of SSAs provide a new clue for improving the physical processes responsible for precipitation of tropical cyclones in numerical models.