Simulation of mineral dust aerosol with Piecewise Log-normal Approximation (PLA) in CanAM4-PAM 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
01 Aug 2012
2Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, British Columbia, Canada
Received: 29 August 2011 – Published in Atmos. Chem. Phys. Discuss.: 22 September 2011 Abstract. A new size-resolved dust scheme based on the numerical method of piecewise
log-normal approximation (PLA) was developed and implemented in the fourth
generation of the Canadian Atmospheric Global Climate Model with the PLA
Aerosol Model (CanAM4-PAM). The total simulated annual global dust emission
is 2500 Tg yr−1, and the dust mass load is 19.3 Tg for year 2000.
Both are consistent with estimates from other models. Results from
simulations are compared with multiple surface measurements near and away
from dust source regions, validating the generation, transport and deposition
of dust in the model. Most discrepancies between model results and surface
measurements are due to unresolved aerosol processes. Biases in long-range
transport are also contributing. Radiative properties of dust aerosol are
derived from approximated parameters in two size modes using Mie theory. The
simulated aerosol optical depth (AOD) is compared with satellite and surface
remote sensing measurements and shows general agreement in terms of the dust
distribution around sources. The model yields a dust AOD of 0.042 and dust
aerosol direct radiative forcing (ADRF) of −1.24 W m−2 respectively,
which show good consistency with model estimates from other studies.
Revised: 18 May 2012 – Accepted: 11 July 2012 – Published: 01 August 2012
Citation: Peng, Y., von Salzen, K., and Li, J.: Simulation of mineral dust aerosol with Piecewise Log-normal Approximation (PLA) in CanAM4-PAM, Atmos. Chem. Phys., 12, 6891-6914, doi:10.5194/acp-12-6891-2012, 2012.