Stratospheric aerosol plays an important role in the climate system, but there remain significant uncertainties in the chemical, dynamical and microphysical processes that determine its distribution and variability. Variations in the stratospheric aerosol layer have a direct impact on climate by changing the Earth's energy balance through scattering of incoming solar radiation. For this reason, it has been suggested that intentional injections of aerosol or aerosol precursors into the stratosphere could be used to mitigate the global warming due to increasing greenhouse gas concentrations. Radiatively driven changes in response to large volcanic eruptions have been shown to impact surface temperatures, atmospheric dynamics and the transport and lifetime of long-lived species that play a role in stratospheric ozone chemistry.
The chemical and radiative impacts of stratospheric aerosol depend on particle size distribution, but models vary significantly both in how they parameterize aerosol microphysical processes and how they simulate size distributions, resulting in divergent predictions of the time evolution of radiative impacts from stratospheric aerosol perturbation events. Measurements to characterize the natural stratospheric aerosol burden, its variability and response to perturbation are needed to refine models that will eventually be used to assess the effects and consequences of potential climate intervention strategies using injected materials to increase stratospheric aerosol loading
B2SAP is a NOAA Earth's Radiation Budget (ERB) Initiative Project.