Following the eruption of Mt. Pinatubo in 1991, aerosol vertical optical depth, (tau_ext) increased globally to ~.15 in the visible and near-IR due to the increase in stratospheric aerosol.

1. What fraction of the incoming photons were scattered in the stratosphere (assume a mean solar zenith angle of 45 degrees).

2. If 90% of the photons were scattered forward, and assuming a pre-Pinatubo planetary albedo of 30%, what was the change in the albedo?

3. From 2., what is the change in Te?

4. Recalculate 3 for the case where the aerosol asymmetry parameter is -1 (100% backscatter).