Sulfate Size Distribution

CSP_SO₄. Contour plot of the non-seasalt SO₄⁼ mass size distribution as a function of Day of Year. Highest nss SO₄⁼ concentrations corresponded to air masses sampled in the region of divergent easterlies where the aerosol boundary layer residence times were relatively long and there was minimal precipitation. Low concentrations were measured near Manus Island (DOY 80 to 93) where there was considerable convective activity and a higher rainfall rate. The regions of highest nss SO₄⁼ concentrations correspond to regions where a spectral scattering response was observed indicating the optical importance of accumulation mode nss SO₄⁼ (unpublished data).