A model of Saharan dust deposition to the eastern Gulf of Mexico

The regional deposition of mineral dust aerosols was simulated from May–October 1999 using a simple two-dimensional model developed specifically to estimate high-resolution (kilometer scale) iron fertilization within the eastern Gulf of Mexico. In this model, daily atmospheric dust concentrations were assumed to be homogeneous over the model domain, where measurements at Miami served as the forcing function. Spatial deposition was driven by spatial variation in precipitation, i.e. wet deposition processes. A daily accumulation index (DAI) was formulated in order to provide high-resolution rainfall rates over time and space.The model calculated that 0.9–2.2 g dust m− 2 (28–78 mg Fe m− 2) was deposited over the model domain during the 6-month simulation. Wet deposition was responsible for 82–93% of total dust deposition. The highest concentrations of dust (iron) were deposited along the coast of west central Florida between 26° and 29°N latitude (Tampa Bay to Charlotte Harbor). This region saw the largest amount of precipitation during periods of elevated mineral dust, with 44–64% of total annual deposition occurring during 5 wet deposition events.

► We model daily dust and iron deposition to the eastern Gulf of Mexico at kilometer scale resolution.
► Total deposition was calculated using wet and dry deposition.
► Wet deposition dominate annual deposition.