Fig. S2.

(A) Soot burden and (B) effective soot particle radius for the first 6 mo of the two 35,000-Tg simulations (with and without the addition of water vapor). Soot burden is from instantaneous, hourly model output; soot radius is from monthly average output. The soot radius shown is the equivalent spherical radius at 100 hPa (solid) and 10 hPa (dashed). When water accompanies the soot injection, a very large amount of soot is removed by precipitation within a few days (A, red curve). In the simulation without water vapor, rapid removal of soot starts around day 60, due to coagulation and sedimentation of large particles (A, blue curve). This effect is seen at 100 hPa but does not occur at 10 hPa, where the mixing ratio of soot is much smaller and very large particles do not form (B).