Direct Measurements of Dry and Wet Deposition of Black Carbon Over a Grassland Journal of Geophysical Research: Atmospheres

The atmospheric lifetime of black carbon (BC) is controlled by wet and dry deposition, which are poorly constrained by observations. We show that the single-particle soot photometer can measure surface-atmosphere exchange fluxes of refractory BC (rBC) particle mass (m(rBC)) and number (N-rBC) by eddy covariance. We report field measurements of rBC dry and wet deposition rates during summer 2017 at the Southern Great Plains site in Oklahoma. On average, dry deposition of rBC is 0.3 +/- 0.2 mm/s. We estimate a wet deposition flux of 2,600 ng . m(-2) center dot hr(-1) over the 148.5 mm of rainfall observed. These data indicate a composite lifetime of 7-11 days.