Incorporating an advanced aerosol activation parameterization into WRF-CAM5: Model evaluation and parameterization intercomparison

Journal Article · Thu Jun 18 00:00:00 EDT 2015 · Journal of Geophysical Research: Atmospheres

DOI:https://doi.org/10.1002/2014JD023051· OSTI ID:1229999

Zhang, Yang ^[1]; Zhang, Xin ^[2]; Wang, Kai ^[2]; He, Jian ^[2]; Leung, L. Ruby ^[3]; Fan, Jiwen ^[3]; Nenes, Athanasios ^[4]

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1. North Carolina State Univ., Raleigh, NC (United States); Collaborative Innovation Center for Regional Environmental Quality, Beijing (China)
2. North Carolina State Univ., Raleigh, NC (United States)
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
4. Georgia Inst. of Technology, Atlanta, GA (United States)

Aerosol activation into cloud droplets is an important process that governs aerosol indirect effects. The advanced treatment of aerosol activation by Fountoukis and Nenes (2005) and its recent updates, collectively called the FN series, have been incorporated into a newly developed regional coupled climate-air quality model based on the Weather Research and Forecasting model with the physics package of the Community Atmosphere Model version 5 (WRF-CAM5) to simulate aerosol-cloud interactions in both resolved and convective clouds. The model is applied to East Asia for two full years of 2005 and 2010. A comprehensive model evaluation is performed for model predictions of meteorological, radiative, and cloud variables, chemical concentrations, and column mass abundances against satellite data and surface observations from air quality monitoring sites across East Asia. The model performs overall well for major meteorological variables including near-surface temperature, specific humidity, wind speed, precipitation, cloud fraction, precipitable water, downward shortwave and longwave radiation, and column mass abundances of CO, SO₂, NO₂, HCHO, and O₃ in terms of both magnitudes and spatial distributions. Larger biases exist in the predictions of surface concentrations of CO and NO_x at all sites and SO₂, O₃, PM_2.5, and PM₁₀ concentrations at some sites, aerosol optical depth, cloud condensation nuclei over ocean, cloud droplet number concentration (CDNC), cloud liquid and ice water path, and cloud optical thickness. Compared with the default Abdul-Razzack Ghan (2000) parameterization, simulations with the FN series produce ~107–113% higher CDNC, with half of the difference attributable to the higher aerosol activation fraction by the FN series and the remaining half due to feedbacks in subsequent cloud microphysical processes. With the higher CDNC, the FN series are more skillful in simulating cloud water path, cloud optical thickness, downward shortwave radiation, shortwave cloud forcing, and precipitation. Here, the model evaluation identifies several areas of improvements including emissions and their vertical allocation as well as model formulations such as aerosol formation, cloud droplet nucleation, and ice nucleation.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF); National Energy Research Scientific Computing Center (NERSC)
• Grant/Contract Number: AC05-76RL01830; OCI‐1053575
• OSTI ID: 1229999
• Report Number(s): PNNL-SA-113221; KP1703010
• Journal Information: Journal of Geophysical Research: Atmospheres, Vol. 120, Issue 14; ISSN 2169-897X
• Publisher: American Geophysical Union
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
WRF‐CAM5
CCN activation
aerosol indirect effects
model improvement and evaluation
East Asia