Small‐particle dry deposition on natural waters: Modeling uncertainty

Several recent articles have used modeling results to calculate sea salt or sulfur exchange between the atmosphere and oceans. In all cases, modeling uncertainty for small‐particle dry deposition is grossly underestimated. This short note discusses the magnitude of uncertainty that presently pervades these modeling results. The conclusion, based on a review of models and the limited experimental data available, is that the uncertainty in small‐particle (diameter D<1 μm) dry deposition to water surfaces is about two orders of magnitude. It is suggested that future calculations of small‐particle atmosphereocean exchange account for this ±1 order of magnitude uncertainty and that direct open‐ocean measurements are needed before any reduced uncertainty may be expected.