Brookhaven Lecture

Aerosols emitted from wildfires and agricultural burns, collectively referred to as biomass burning (BB), are recognized to perturb Earth's climate through the "direct" effect (the scattering and absorption of incoming shortwave radiation), the "semi-direct" effect (evaporation of cloud drops and modification of atmospheric dynamics), and "indirect" effects (influencing cloud formation and precipitation). These events are an important aerosol source, providing an estimated 50% of anthropogenically influenced fine carbonaceous particles and are responsible for about 40% of the global atmospheric inventory of black carbon (BC) – a warming agent second only to CO2. Additionally, the scientific community now recognizes that these events also generate light-absorbing organic compounds, known as brown carbon (BrC). The overall of these particles on the atmospheric radiation balance, either forcing the atmosphere to heat or to cool, depends on the abundance, cloud forming activity, and refractive index (specifically the
absorption) of emitted primary particles and secondary aerosol species. During the summer and fall of 2013, the Department of Energy's Atmospheric Radiation Measurement (ARM) program sponsored an aircraft study to investigate the near source evolution (