Atmospheric aerosols show large variations in size, morphology, chemical composition and optical properties. These variations, combined with an incomplete understanding of their evolution, yield a large uncertainty in how global aerosol loading affects the radiation budget of the Earth. Many questions arise: How much of a climate-cooling influence do aerosols presently exert? How much of the aerosol radiative forcing can be attributed to variations in cloud cover relative to direct interaction with solar radiation? How well do climate models account for the influence of aerosols? How do uncertainties in aerosol properties affect model uncertainties, and how large are those uncertainties? Does cooling due to aerosols counter warming due to greenhouse gases and how much? To address these questions, policy makers, regulators, industrial leaders, and climate scientists have a strong need for quantitative information about the physical and chemical properties of aerosol particles, particularly as they affect the interaction of aerosols with solar radiation.
The National Institute of Standards and Technology (NIST) is sponsoring a topical workshop to identify the standards and measurement needs and challenges in this arena. This workshop will identify areas of high uncertainty, recognize opportunities, and stimulate new ideas — information that will accelerate the development of new measurement technologies and shape the aerosol metrology climate research agenda.