Eolian dust and climate: relationships to sources, tropospheric chemistry, transport and deposition

The amount of atmospheric dust suspended in the atmosphere and subsequently deposited on land and in the oceans is largely controlled by processes related to climate; however, the dust's presence in the atmosphere also can affect climate and, as a result, feedbacks between dust and climate are possible. By scattering and absorbing incoming solar and outgoing infrared radiation, dust particles can alter the Earth's radiative balance. The net effect of the Earth's dust veil can be one of heating or cooling depending on a number of variables. especially the concentration, composition and physical properties of the dust; the albedo of the surface underlying the suspended dust; and the vertical distribution of dust in the atmosphere. Indirect feedbacks between dust and climate also are possible as a result of the dust's chemical reactivity and involvement in the biogeochemical cycles of other substances with links to climate. Studies of modem dust fluxes and their connections to climate are important, not only for developing methods 'for predicting the impacts of future climate change scenarios, but also for strengthening the underpinnings of paleoclimate reconstructions. (C) 2001 Elsevier Science B.V. All rights reserved.