Quantification of marine aerosol subgrid variability and its correlation with clouds based on high-resolution regional modeling: Quantifying Aerosol Subgrid Variability

Journal Article · Fri Jun 16 04:00:00 EDT 2017 · Journal of Geophysical Research: Atmospheres

DOI:https://doi.org/10.1002/2017JD026567· OSTI ID:1374643

Lin, Guangxing ^[1]; Qian, Yun ^[1]; Yan, Huiping ^[2]; Zhao, Chun ^[3]; Ghan, Steven J. ^[1]; Easter, Richard ^[1]; Zhang, Kai ^[1]

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1. Pacific Northwest National Laboratory, Richland Washington USA
2. Pacific Northwest National Laboratory, Richland Washington USA; College of Atmospheric Science, Nanjing University of Information and Technology, Nanjing China
3. Pacific Northwest National Laboratory, Richland Washington USA; School of Earth and Space Sciences, University of Science and Technology of China, Hefei China

One limitation of most global climate models (GCMs) is that with the horizontal resolutions they typically employ, they cannot resolve the subgrid variability (SGV) of clouds and aerosols, adding extra uncertainties to the aerosol radiative forcing estimation. To inform the development of an aerosol subgrid variability parameterization, here we analyze the aerosol SGV over the southern Pacific Ocean simulated by the high-resolution Weather Research and Forecasting model coupled to Chemistry. We find that within a typical GCM grid, the aerosol mass subgrid standard deviation is 15% of the grid-box mean mass near the surface on a 1 month mean basis. The fraction can increase to 50% in the free troposphere. The relationships between the sea-salt mass concentration, meteorological variables, and sea-salt emission rate are investigated in both the clear and cloudy portion. Under clear-sky conditions, marine aerosol subgrid standard deviation is highly correlated with the standard deviations of vertical velocity, cloud water mixing ratio, and sea-salt emission rates near the surface. It is also strongly connected to the grid box mean aerosol in the free troposphere (between 2 km and 4 km). In the cloudy area, interstitial sea-salt aerosol mass concentrations are smaller, but higher correlation is found between the subgrid standard deviations of aerosol mass and vertical velocity. Additionally, we find that decreasing the model grid resolution can reduce the marine aerosol SGV but strengthen the correlations between the aerosol SGV and the total water mixing ratio (sum of water vapor, cloud liquid, and cloud ice mixing ratios).

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1374643
• Report Number(s): PNNL-SA-126774; KP1703020
• Journal Information: Journal of Geophysical Research: Atmospheres, Journal Name: Journal of Geophysical Research: Atmospheres Journal Issue: 12 Vol. 122; ISSN 2169-897X
• Publisher: American Geophysical Union
• Country of Publication: United States
• Language: English

Related Subjects

GCM
aerosols
atmospheric
clouds
global climate models
subgrid