Dry deposition of trace elements to the western North Atlantic

Abstract

Data for Al, Fe, Na, Sb, Se V, and Zn in aerosol particles from Bermuda are used in combination with parameterized dry deposition velocities to investigate trace element recycling on atmospheric sea salt. During July and August, which are in the high dust season, >10% of the monthly mean aerosol Na can be ascribed to crustal sources rather than sea salt, but in general the contribution of mineral dust to Na dry deposition is small (∼1%) relative to that from sea salt. In fall and winter, ∼10 to 20% of the aerosol Al, a commonly used indicator of mineral dust, is attributable to recycled sea salt, but the dust fluxes then are small, and longer‐term averages show a recycling effect of only 1 to 5% on dry deposition. The percentage of recycled Fe appears to be even less than for Al. Noncrustal/non‐sea‐salt (NC/NSS) sources account for >70% of the aerosol Sb, Se, V, and Zn, but differences in the dry deposition velocities for three particle types strongly affect their air/sea exchange. Dust can account for more than half of the new dry deposition inputs of V and Zn while the amounts of Sb and Se recycled on sea spray approach or exceed their new inputs from dust and the NSS/NC sources.