Aerosol iron and Al solubility from particle size

4 Mineral aerosol deposition is recognized as the dominant source of iron to the open 5 ocean and solubility of iron in the dust aerosol is highly uncertain. Previous solubility 6 estimates range widely from 0.01-80%. We developed two conceptual models to solve 7 for the solubility of different particle sizes—diffusion-controlled model and surface8 controlled model. We are able to produce time and spatial varying solubility maps for 9 aerosol Fe and Al using the dust age at deposition, size-resolved dust deposition field, 10 approximated pH distribution and the two conceptual models. The surface-controlled 11 model simulates solubility that varies more than the diffusion-controlled model and 12 better captures the spatial pattern of observed solubility in the Atlantic Ocean. How13 ever, neither of these two models could explain the large solubility variation observed 14 in the Pacific Ocean. Using these solubility maps produce very different soluble iron 15 deposition flux from the global uniform solubility. We examine the impacts of spatially 16 variable, size-dependent solubility on marine biogeochemistry with the Biogeochem17 ical Elemental Cycling (BEC) ocean model by comparing the modeled surface ocean 18 dissolved Fe and Al with observations. Diffusion-based variable solubility does not 19 significantly change the fit of dissolved Fe from using 5% uniform solubility while the 20 surface-based variable solubility improves the comparison in the north Atlantic Ocean 21 but worsens in the Pacific Ocean and the Indian Ocean. 22