Effects of Anthropogenic Gaseous Emissions on the Microphysical Properties of a Landfalling Tropical Cyclone

Using the Weather Research and Forecasting model with chemistry module, Typhoon Nida (2016) is simulated to investigate the effects of anthropogenic gaseous emissions on vortex system. Based on the Multi-resolution Emission Inventory for China (MEIC), three experiments with base-level emission intensity (CTRL), one-tenth the emission intensity of (SO2_C) or (NH3_C) are conducted, respectively. Results show that the simulations reasonably reproduce the typhoon track and intensity and are slightly sensitive to the anthropogenic emissions compared with the CMA best-track dataset. However, clear differences of cloud microphysical properties exist in the two sensitivity runs, and the impacts of are generally larger than those of . Compared with the polarimetric radar observation, the smaller (larger) values of differential reflectivity are produced in the SO2_C (NH3_C) run, and the thence smaller-sized raindrops can lead to weaker rainfall intensity. When the main core of typhoon locates over the ocean, a prolonged duration of raindrop growth along with more precipitation occurs in the CTRL run probably due to the suppression of warm-rain processes and the enhancement of convection. In addition, the most latent heat release associated with water vapor condensation in the CTRL run indicates the strongest upward motion and the warmest core structure among these three runs. The thermodynamic evolution of vortex becomes complex when it makes landfall, more water vapor condensation and stronger updraft still present in the NH3_C run than those in the SO2_C run as a combined result of higher cloud droplet concentration and relative humidity in the former.