High-resolution modeling of aerosol composition and optical properties associated with anthropogenic and biogenic precursor emissions during CARES
Poster PDF
Authors
Jerome D Fast — Pacific Northwest National Laboratory
Manishkumar Shrivastava — Pacific Northwest National Laboratory
Ying Liu — Pacific Northwest National Laboratory
Rahul Zaveri — Pacific Northwest National Laboratory
Louisa Emmons — National Center for Atmospheric Research (NCAR)
John E Shilling — Pacific Northwest National Laboratory
Chen Song — Pacific Northwest National Laboratory
Qi Zhang — University of California, Davis
Arthur J Sedlacek — Brookhaven National Laboratory
R. Subramanian — Carnegie Mellon University
Bertram Tom Jobson — Washington State University
James Barnard — University of Nevada Reno
Richard A. Ferrare — NASA - Langley Research Center
Chris A. Hostetler — NASA Langley Research Center
Description
The WRF-Chem model is used with a grid spacing of 4 km to simulate the life cycle of aerosols in central California during the entire CARES campaign, conducted in June 2010. Measurements collected at the two surface sites and on the G-1 and B-200 aircraft are used to evaluate the simulation, particularly anthropogenic and biogenic trace gas precursors of aerosols and aerosol mass, composition (e.g., sulfate, nitrate, ammonium, chloride, black carbon, organic matter) and optical properties (e.g., aerosol optical depth, single-scattering albedo). Anthropogenic emissions are obtained from the California Air Resources Board, biogenic emissions are computed on-line using the MEGAN model, and the initial and lateral boundary conditions for meteorology and chemistry are based on the NAM and MOZART models, respectively. This simulation is meant to provide a benchmark for future simulations that will incorporate improved treatments of secondary organic aerosols and aerosol mixing state within the framework of the MOSAIC aerosol treatment in WRF-Chem. Observations show that the first part of the campaign was characterized by clean conditions with very low aerosol concentrations, but the meteorological conditions became more favorable for aerosol formation during the last week of June. Therefore, the ability of the model to simulate the diurnal and multiday variations in aerosols will be examined. Predicted spatial variations in aerosols associated with the Sacramento and Bay Area plumes will be compared with data from the G-1 aircraft as well as with profiles of backscatter and extinction measured by the High Spectral Resolution Lidar (HSRL) on the B-200 aircraft. Fast et al. (2011) found that the WRF model was able to simulate the meteorology and transport of carbon monoxide tracers reasonably well during the campaign and that local recirculation processes were likely responsible for observed aerosol layers over the Sacramento Valley in the morning. The simulation will therefore be analyzed to determine how recirculation affects aerosol aging in the vicinity of Sacramento. We will also identify the likely sources of model errors, such as uncertainties in emissions and the treatment of secondary organic aerosols, and describe how those errors affect how aerosols influence the local radiation budget.
