About 89% of the direct radiative forcing from the atmospheric aerosols occurred
immediately after the fire during the latter part of June. Another 11% occurred during
July, with negligible contributions in subsequent months. The annual radiative forcing
from atmospheric aerosols was 17 ± 30 W m-2. Our error estimate includes a large
component caused by interannual variability in climate within CAM 3. Interannual
variability in wind direction and strength at the point source, near-source snow and cloud
conditions, and precipitation patterns influenced aerosol lifetimes and the strength of their
forcing. At the surface, the perturbation to net shortwave radiation from both aerosol
absorption and scattering was substantially larger and led to a net cooling of -90 ± 35 W
m-2.