Quantifying Atmospheric Trace Element Deposition over the Ocean on a
Global Scale with Satellite rainfall products
Abstract
Atmospheric input of trace element micronutrients to the oceans is
difficult to determine as even with collection of high-quality aerosol
chemical concentrations such data by themselves cannot yield deposition
rates. To transform these concentrations into rates, a method of
determining flux by applying an appropriate deposition velocity is
required. A recently developed method based on the natural radionuclide
Be has provided a means to estimate the bulk (wet + dry) deposition
velocity (V) required for this calculation. Here, water column Be
inventories and aerosol Be concentrations collected during the 2018 US
GEOTRACES Pacific Meridional Transect are presented. We use these data
together with those from other ocean basins to derive a global
relationship between rain rate (m/y) and bulk depositional velocity
(m/d), such that V= 999±96 x Rain rate + 1040±136 (R=0.81). Thus with
satellite -derived rainfall estimates, a means to calculate aerosol bulk
deposition velocities is provided.