Abstract
The typhoon Fanapi (14-23 Sept. 2010) is simulated for three different concentrations of cloud condensation nuclei (CCN) by using the Weather Research and Forecasting model (WRF). Sensitivity tests were carried out for varying aerosol concentrations, to determine the average and maximum response of microphysical processes of five different hydrometeors, minimum sea level pressure (MSLP), wind speed and radar reflectivity, to CCN. The clean case is ruminated as standard for comparison. MSLP increased by up to 7 hPa with higher concentration of CCN. The typhoon speed with higher CCN concentration remained faster, while surface wind speed remained higher for lower CCN simulation. Rainfall exhibits the momentous, spatial and temporal variability. The enhanced CCN concentration augmented rain / cloud droplet concentration and their mass mixing ratio. The concentration of graupel particles augmented with simulation time. The number concentration and mass mixing ratio of ice crystals were also observed on higher side with increased polluted cases, at mature stages. The increasing CCN reduces warm rain at early stage, responding into numerous snow particles, to grow by coagulations with cloud and rain drops at higher levels and stay longer in the atmosphere. It results in intensified precipitation at the later stage. Radar reflectivity also increased with higher CCN at initial and dissipating stages. The high CCN concentration delayed the typhoon growth by stirring up changes in hydrometeor properties, transforming the thermodynamic structure and hurricane diabetic heating distribution, and hence resulting into impact on typhoon intensity through comprehensive dynamical changes.