Distribution, transport, and deposition of mineral dust in the Southern Ocean and Antarctica: Contribution of major sources

A model-based investigation of the transport, distribution and deposition of mineral dust in the Southern Hemisphere (SH) is performed by using the GFDL Atmospheric Model (AM2). The study represents an attempt to quantify the contribution of the major sources by tagging dust based on its origin. We evaluate the contribution of each source to the emission, distribution, mass burden and deposition of dust in the Southern Ocean and Antarctica, and show that each source produces distinctive meridional transport, vertical distribution, and deposition patterns. The dust in SH originates primarily from Australia (120 Tg a(-1)), Patagonia (38 Tg a(-1)) and the inter-hemispheric transport from Northern Hemisphere (31 Tg a(-1)). A small fraction of it (7 Tg a(-1)) is transported and deposited in the Southern Ocean and Antarctica, where dust from South America, Australia, and Northern Hemisphere are essentially located in the boundary layer, mid-troposphere, and upper-troposphere, respectively. These three sources contribute to nearly all the dust burden in the Southern Ocean and Antarctica. South America and Australia are the main sources of the dust deposition, but they differ zonally, with each one dominating half of a hemisphere along 120 degrees E-60 degrees W: the half comprising the Atlantic and Indian oceans in the case of the South American dust and the Pacific half in the case of the Australian dust. Our study also indicates a potentially important role of Northern Hemisphere dust, as it appears to be a significant part of the dust burden but contributing little to the dust deposition in Antarctica.