Radiative forcing by volcanic aerosols from 1850 to 1994

We use our detailed radiative transfer model and the latitude-altitude dist ributions of zonal mean optical properties for the Pinatubo aerosol to calc ulate the time evolution of its instantaneous radiative forcing. We represe nt the zonal mean of this radiative forcing in terms of the zonal mean opti cal depth of the Pinatubo aerosol, together with the solar insolation, effe ctive emitting temperature, daylight fraction of a day, and the planetary a lbedo in the absence of the aerosol. We use this representation, together w ith the volcano optical depths compiled by Sato et al. [1993], to calculate the instantaneous and adjusted radiative forcing by volcanic aerosols from 1850 to 1994.