Assessing estimates of radiative forcing for solar geoengineering starts with accurate aerosol radiative properties

John A Dykema1, David Keith1 and Frank N Keutsch2, (1)Harvard University, School of Engineering and Applied Sciences, Cambridge, MA, United States, (2)Harvard University, School of Engineering and Applied Sciences, Department of Chemistry and Chemical Biology, and Department of Earth and Planetary Sciences, Cambridge, MA, United States