Effects of Aerosols on the Precipitation of Convective Clouds: A Case Study in the Yangtze River Delta of China. Issue 14 (17th July 2019)

• Record Type: Journal Article
• Authors: Liu, Chong; Wang, Ti‐Jian; Chen, Pu‐Long; Li, Meng‐Meng; Zhao, Ming; Zhao, Kun; Wang, Ming‐Huai; Yang, Xiu‐Qun
• Is Part Of: Journal of geophysical research. Volume 124:Issue 14(2019)
• Page Start: 7868
• Page End: 7885
• Publication Date: 2019-07-17
• Subjects: aerosols -- cloud condensation nuclei -- convective cloud precipitation -- WRF‐Chem; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2018JD029924
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Aerosol is a critical factor affecting the atmospheric hydrological cycle and climate change. Acting as cloud condensation nuclei for cloud formation, aerosols have a significant impact on regional precipitation. This study uses the fully coupled chemistry module (Weather Research and Forecasting/Chem) within the Weather Research and Forecasting model to simulate convective cloud precipitation in the Yangtze River Delta of China. To investigate the impact of on precipitation, four numerical experiments are conducted. The base case uses the full emission inventory (which we call the 100% case), and the other three cases are designed based on reduced emissions for different percentages (which we call the 50% case, the 10% case, and the 1% case). Compared to the other cases, the grid point hour maximum precipitation of the 50% case is the largest, which can reach 44.1 mm/hr and has an increase of 5% over the 100% case. The strongest precipitation is delayed by about 1 hr in the 50% case, and precipitation area is increased by 6.5%. This study indicates that the influence of aerosols on regional precipitation is a nonlinear process, with a correlation coefficient of 0.52 ( p <0.01) showing a strong positive correlation between cloud condensation nuclei (>250 cm −3, height of 0.5–3 km) and precipitation. Further analysis of the dynamics and microphysical processes of this convective precipitation shows that the 50% case has an area with higher rising velocity and bigger cloud water mixing ratio than the other cases but has a relatively low convective center. The formation of precipitation is mainly influenced by the accretion of snow by rain, but the role of the snow melting into rain cannot be ignored. Key Points: Aerosols play different roles in promoting the development of convection and microphysical processes; the synthesis shows the influence of nonlinearity on precipitation, only when appropriate concentration can promote precipitation CCN (>250 cm −3 ) converted from appropriate concentration aerosols can significantly enhance this precipitation For a heavy convective precipitation system in the Yangtze River Delta, aerosols can affect precipitation by changing convective structures and microphysical processes