Volume 11, No. 1, February 2011, Pages 21-30 PDF(695 KB)
Eliminating Numerical Artifacts When Presenting Moving Center Sectional Aerosol Size Distributions
Adam J. Mohs, Frank M. Bowman
Department of Chemical Engineering, University of North Dakota, 241 Centennial Drive Stop 7101, Grand Forks, ND 58202-7101, USA
A number of atmospheric aerosol models use the moving center sectional (MCS) method to represent the aerosol size distribution. Distributions generated via MCS may exhibit numerical artifacts during condensational growth which appear as extraneous “pits” and “peaks” in the distribution. The use of remapping and smoothing methods to eliminate these numerical artifacts when presenting size distribution results is examined. Three remapping methods based on linear interpolation and two smoothing approaches were tested for use on output distributions from MCS simulations. Model predictions of condensational growth using the MCS method with and without smoothing and remapping are compared to an accurate analytical solution. Results indicate that one remapping method, the zero mass exclusive method, completely removed “pits” and “peaks” that form in high resolution, 48-section distributions, whereas the other potential correction methods only partially removed the artifacts. For lower resolution 12-section distributions, where pits and peaks are not formed, the remapping methods provide smaller improvements in how MCS distributions are depicted and smoothing approaches result in significant numerical diffusion.
Condensational growth; Modeling; Artifact correction; Aerosol size structure.