Abstract
Abstract. We quantified the effects of the plume rise of biomass burning aerosol and gases for the forest fires that occurred in Saskatchewan, Canada, in July 2010. For this purpose, simulations with different assumptions regarding the plume rise and the vertical distribution of the emissions were conducted. Based on comparisons with observations, applying a one-dimensional plume rise model to predict the injection layer in combination with a parametrization of the vertical distribution of the emissions outperforms approaches in which the plume heights are initially predefined. Approximately 30 % of the fires exceed the height of 2 km with a maximum height of 8.6 km. Using this plume rise model, comparisons with satellite images in the visible spectral range show a very good agreement between the simulated and observed spatial distributions of the biomass burning plume. The simulated aerosol optical depth (AOD) with data of an AERONET station is in good agreement with respect to the absolute values and the timing of the maximum. Comparison of the vertical distribution of the biomass burning aerosol with CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) retrievals also showed the best agreement when the plume rise model was applied. We found that downwelling surface short-wave radiation below the forest fire plume is reduced by up to 50 % and that the 2 m temperature is decreased by up to 6 K. In addition, we simulated a strong change in atmospheric stability within the biomass burning plume.
Highlights
Emissions from biomass burning significantly contribute to the global atmospheric aerosol mass (Stocker et al, 2013)
We extended the model system COSMO-ART with an online-coupled one-dimensional plume rise model to parametrize the effective source heights for vegetation fires with high energy input
The improved model system was used to quantify the effects of biomass burning aerosol on radiation and temperature during an intensive fire event that occurred in July 2010 in Canada
Summary
Emissions from biomass burning significantly contribute to the global atmospheric aerosol mass (Stocker et al, 2013). The stable meteorological conditions and homogeneous cloud distribution in the Amazon without the presence of smoke provided an ideal basis for investigating the impact of biomass burning aerosol on cloud formation. Wang et al (2013) simulated the transport of smoke from fires over the Southeast Asian Maritime Continent for September and October 2006 They concluded that in comparison with CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) observations simulations with homogeneous emissions between the surface and 800 m provided the best agreement for the aerosol profile in their case. To the best of our knowledge we are the first to investigate the effect of biomass burning aerosol on temperature and dynamics with an online-coupled modeling system on synoptic timescales with an explicit treatment of the aging of soot in combination with a plume rise model. A comparison with observations is given, and the impacts of the biomass burning emissions on radiation and temperature are presented
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
