Investigation of the Effects of Anthropogenic Pollution on Typhoon Precipitation and Microphysical Processes Using WRF-Chem

Abstract

Taking Typhoon Usagi (2013) as an example, this study used the Weather Research and Forecasting Model with Chemistry to investigate the influence of anthropogenic aerosols on typhoons. Three simulations (CTL, CLEAN, EXTREME) were designed according to the emission intensity of the anthropogenic pollution. The results showed that although anthropogenic pollution did not demonstrate clear influence on the track and strength of the typhoon, it clearly changed the precipitation, distribution of water hydrometeors, and microphysical processes. In the CLEAN experiment, the precipitation rate declined because cloud water collected by the rain decreased. Similarly, the precipitation rate decreased in the EXTREME experiment, because the autoconversion of cloud water to rain was restrained. Regarding precipitation type, the rate of stratiform precipitation in both the CLEAN and the EXTREME simulations was suppressed because the ice-phase microphysical processes weakened. Compared with the CTL run, the rate of stratiform precipitation at the periphery of the typhoon was reduced by about 28% in both the CLEAN and the EXTREME simulations. Moreover, the rate of convective precipitation within 140–160 km of the center of the typhoon in the EXTREME experiment was about 33% greater than in the CTL simulation. This increase was triggered by new convection at the periphery in the EXTREME simulation related to cloud water reevaporation. Finally, compared with the CTL experiment, the peaks of both convective and mixed precipitation in the CLEAN and EXTREME experiments shifted 10 km toward the typhoon periphery.

Effects of turbulence‐induced collision enhancement on heavy precipitation: The 21 September 2010 case over the Korean Peninsula

“…It is noted that in the simulation results of this study, the maximum cloud droplet number concentration, which is mainly controlled by the initial aerosol number concentration, is 83 cm −3 . This value is somewhat small from the point that the area of interest is mostly land, although some studies also report the maximum cloud droplet number concentration similar to that of this study [e.g., Jiang et al , ]. In future studies, more proper treatments of aerosol number concentration and aerosol‐related physical processes would be helpful.…”

Effect of melting processes on the structure and precipitation of a heavy rainstorm in Beijing

“…The heat exchange during these processes can greatly affect the stratification of temperature and humidity, the thermal and dynamic structure of the atmosphere, and the development and evolution of clouds and precipitation. Due to lack of measurement methods, numerical models have become an effective tool to investigate microphysical processes (Gilmore and Straka, ; Sui et al ., ; Tao et al ., ; Yang et al ., , ; Adams‐Selin et al ., ; Li et al ., , ; Jiang et al ., ; Huang and Cui, 2015; Yang et al ., ; Song and Sohn, 2018; Li et al ., ; Guo et al ., ).…”

Effects of Anthropogenic Aerosols on a Heavy Rainstorm in Beijing

“…The researchers found that the variation in aerosol concentrations had significant effects on the cloud microphysical processes, as well as on hail precipitation during hailstorms at the surface. Jiang et al [36] simulated a typhoon in China using the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem). The results showed that with changes in anthropogenic aerosols, the formation processes of hydrometeors in the cloud system of the typhoon and the related latent heat changed simultaneously.…”