The changes in precipitation in north-eastern North America caused by chemistry-and particularly anthropogenic aerosols-are investigated using the Weather Research Forecasting with Chemistry (WRF/Chem v3.2) model. The simulations were carried out for a five-month period from April to August 2009. The model results show that non-negligible changes in both convective and cloud-resolved (non-convective) precipitation are caused by chemistry and/or aerosols over most parts of the domain. The changes can be attributed to both radiative and microphysical interactions with the meteorology. A chemistry-induced change of approximately 15% is found in the five-month mean daily convective precipitation over areas with high convective rain; most of this can be traced to radiative effects. Total convective rain is greater than total non-convective rain in the domain, but a chemistry-induced increase of about 30% is evident in the five-month mean daily non-convective precipitation over the heavily urbanized parts of the Atlantic coast. The effects of aerosols on cloud microphysics and precipitation were examined for two particle size ranges, 0.039-0.1 Î1/4m and 1-2.5 Î1/4m, representing the nucleation and accumulation modes respectively. Strongly positive spatial correlation between cloud droplet number and non-convective rain are found for activated (cloud-borne) aerosols in both size ranges. Non-activated (interstitial) aerosols have a positive correlation with cloud droplet number and non-convective rain when they are small and an inverse correlation for larger sizes. © 2014 Author(s).
CITATION STYLE
Mashayekhi, R., & Sloan, J. J. (2014). Effects of aerosols on precipitation in north-eastern North America. Atmospheric Chemistry and Physics, 14(10), 5111–5125. https://doi.org/10.5194/acp-14-5111-2014
Mendeley helps you to discover research relevant for your work.