AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Impacts of New Particle Formation on Midwestern Climate and Air Quality as Determined by the NPF-explicit WRF-Chem
CAN DONG, Charles Stanier, Robert Bullard, Ashish Singh, University of Iowa
Abstract Number: 138 Working Group: Aerosols, Clouds, and Climate
Abstract New particle formation (NPF) and growth can influence the concentration of aerosols and cloud droplets, which have been acknowledged to play an important role in both global climate and human health. Several mechanisms have been proposed to explain secondary particle formation and growth. In this study, the NPF explicit version (Matsui et al, Journal of Geophysical Research, 116(D19208), 2011) of the Weather Research and Forecasting Chemistry (WRF-chem) model was used to simulate the particle number distribution in the Midwest.
The three-dimensional chemical transport model has a total of 20 size bins ranging 1-10000 nm in diameter. Particle number concentration, aerosol size distribution, and cloud droplet concentration were simulated in spring and summer 2008 and evaluated versus aircraft and surface measurements in the Midwest. Impacts of NPF on downward solar radiation, surface temperature, relative humidity, PBL height, condensation nuclei (CN), cloud condensation nuclei (CCN), COD, PM2.5 and SO2 will be evaluated. Sensitivity of model prediction to selection of empirical nucleation schemes (activation and kinetic) and the binary homogeneous nucleation will be investigated in the boundary layer and the free troposphere, respectively.
Differences between nucleation-on and nucleation-off simulations in summer show that contributions of NPF to the surface CN10 (> 10 nm in diameter) and CCN (at S =1%) concentrations are 20% and 2.5%, respectively. Aspects to be discussed include the selection of activation and kinetic coefficients, and impacts of NPF to climate and air quality in different seasons.