Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 10887-10904, 2015
https://doi.org/10.5194/acp-15-10887-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
30 Sep 2015
Simulation of black carbon in snow and its climate impact in the Canadian Global Climate Model
M. Namazi1,a, K. von Salzen1, and J. N. S. Cole1 1Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, British Columbia, Canada
anow at: Department of Mathematics, University of Isfahan, Isfahan, Iran
Abstract. A new physically based parameterisation of black carbon (BC) in snow was developed and implemented in the Canadian Atmospheric Global Climate Model (CanAM4.2). Simulated BC snow mixing ratios and BC snow radiative forcings are in good agreement with measurements and results from other models. Simulations with the improved model yield considerable trends in regional BC concentrations in snow and BC snow radiative forcings during the time period from 1950–1959 to 2000–2009. Increases in radiative forcings for Asia and decreases for Europe and North America are found to be associated with changes in BC emissions. Additional sensitivity simulations were performed in order to study the impact of BC emission changes between 1950–1959 and 2000–2009 on surface albedo, snow cover fraction, and surface air temperature. Results from these simulations indicate that impacts of BC emission changes on snow albedos between these 2 decades are small and not significant. Overall, changes in BC concentrations in snow have much smaller impacts on the cryosphere than the net warming surface air temperatures during the second half of the 20th century.

Citation: Namazi, M., von Salzen, K., and Cole, J. N. S.: Simulation of black carbon in snow and its climate impact in the Canadian Global Climate Model, Atmos. Chem. Phys., 15, 10887-10904, https://doi.org/10.5194/acp-15-10887-2015, 2015.
Publications Copernicus
Download
Short summary
A new parameterization of black carbon in snow in the Canadian Atmospheric Global Climate Model provides realistic simulations of radiative forcings. BC emissions and simulated BC concentrations in snow have changed substantially in recent decades. However, simulated impacts of changes in BC concentrations in snow from 1950-1959 to 2000-2009 on snow reflectivity and snow extent in the Northern Hemisphere are very small, with few regional exceptions, in contrast to results from earlier studies.
A new parameterization of black carbon in snow in the Canadian Atmospheric Global Climate Model...
Share