Investigation of Aerosol Indirect Effects on Simulated Flash-flood Heavy Rainfall over Korea

Journal Article · Thu Nov 01 04:00:00 EDT 2012 · Meteorology and Atmospheric Physics, 118(3-4):199–214

DOI:https://doi.org/10.1007/s00703-012-0216-6· OSTI ID:1055396

Lim, Kyo-Sun; Hong, Songyou

This study investigates aerosol indirect effects on the development of heavy rainfall near Seoul, South Korea, on 12 July 2006, focusing on precipitation amount. The impact of the aerosol concentration on simulated precipitation is evaluated by varying the initial cloud condensation nuclei (CCN) number concentration in the Weather Research and Forecasting (WRF) Double-Moment 6-class (WDM6) microphysics scheme. The simulations are performed under clean, semi-polluted, and polluted conditions. Detailed analysis of the physical processes that are responsible for surface precipitation, including moisture and cloud microphysical budgets shows enhanced ice-phase processes to be the primary driver of increased surface precipitation under the semi-polluted condition. Under the polluted condition, suppressed autoconversion and the enhanced evaporation of rain cause surface precipitation to decrease. To investigate the role of environmental conditions on precipitation response under different aerosol number concentrations, a set of sensitivity experiments are conducted with a 5 % decrease in relative humidity at the initial time, relative to the base simulations. Results show ice-phase processes having small sensitivity to CCN number concentration, compared with the base simulations. Surface precipitation responds differently to CCN number concentration under the lower humidity initial condition, being greatest under the clean condition, followed by the semi-polluted and polluted conditions.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1055396
• Report Number(s): PNNL-SA-91952; KP1703010
• Journal Information: Meteorology and Atmospheric Physics, 118(3-4):199–214, Journal Name: Meteorology and Atmospheric Physics, 118(3-4):199–214 Journal Issue: 3-4 Vol. 118; ISSN 0177-7971
• Country of Publication: United States
• Language: English

Related Subjects

Korea
aerosol
flash-flood
heavy
indirect
investigation
rainfall
simulated