A global three‐dimensional model study of carbonaceous aerosols

Abstract

We have developed detailed emission inventories for the amount of both black and organic carbon particles from biomass burning sources (wood fuel, charcoal burning, dung, charcoal production, agricultural, savanna and forest fires). We have also estimated an inventory for organic carbon particles from fossil fuel burning and urban activities from an existing inventory for fossil fuel sources of black carbon. We also provide an estimate for the natural source of organic matter. These emissions have been used together with our global aerosol model to study the global distribution of carbonaceous aerosols. The accuracy of the inventories and the model formulation has been tested by comparing the model simulations of carbonaceous aerosols in the atmosphere and in precipitation with observations reported in the literature. For most locations and seasons, the predicted concentrations are in reasonable agreement with the observations, although the model underpredicts black carbon concentrations in polar regions. The predicted concentrations in remote areas are extremely sensitive to both the rate of removal by wet deposition and the height of injection of the aerosols. Finally, a global map of the aerosol single scattering albedo was developed from the simulated carbonaceous particle distribution and a previously developed model for aerosol sulfates. The computed aerosol single scattering albedos compare well with observations, suggesting that most of the important aerosol species have been included in the model. For most locations and seasons, the single scattering albedo is larger than 0.85, indicating that these aerosols, in general, lead to a net cooling.

Fire emission heights in the climate system – Part 2: Impact on transport, black carbon concentrations and radiation

“…Due to a lack of observational plume height data sets of global coverage, our knowledge regarding appropriate emission height parametrizations for specific global modeling applications is largely based on short-term or regional studies. By application of inverse Lagrangian modeling techniques, the early studies of Liousse et al (1996), Wotawa and Trainer (2000) and Spichtinger et al (2001) found the best matches of modeled aerosol transport to observations for emission distributions between 0 and 2, 0.5 and 3, and 3 and 5 km for BC, CO and NO x concentrations, respectively. Chen et al (2009) showed that emission heights are substantially more important for BC than for trace gases, which questions the general transferability of the results from trace gas studies to BC.…”

Historical evolution of radiative forcing of climate

“…For this study, we have now estimated the 1995 radiative forcing due to fossil fuel organic carbon aerosol to !0.09 W m\ for 1995. The calculation is performed based on Mie theory for the optical properties and a linear mass relationship between organic carbon and soot as suggested in Liousse et al (1996). We used the same soot distribution as in Myhre et al (1998b).…”

Canadian Aerosol Module: A size‐segregated simulation of atmospheric aerosol processes for climate and air quality models 1. Module development

“…The inclusion of interactive aerosol constituents in GCMs to study the climate impact is still at an early stage, especially for size-segregated multicomponent aerosol processes. Individual bulk or size-segregated aerosol types have been incorporated into various GCMs to study the climatic effects [Adams et al, 2001;Chin et al, 1996;Ghan et al, 2001aGhan et al, , 2001bGhan et al, , 2001cGinoux et al, 2001;Liousse et al, 1996;Lohmann et al, 1999;Tegen and Fung, 1994;Tegen et al, 1997]. The inclusion of an interactive aerosol module in GCMs is the most ideal way to assess the aerosol impact on climate by feeding back both the direct and in-direct aerosol forcing into the GCM dynamical equations.…”