The Atmospheric Transport and Deposition of Major Continental Aerosol Species Over the North Atlantic Ocean

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Over the past 10-15 years atmospheric chemistry has evolved from a young research discipline devoted primarily to local problems of urban pollution and air quality to a mature science concerned with the hemispheric to global scale cycling of a wide variety of chemical species. To a large extent this change has resulted from an increasing realization that human activities can cause chemical disturbances to the natural troposphere on scales far beyond local concerns. Well-known examples include changes in the regional-to-global concentrations of certain nitrogen compounds, lead and other heavy metals, artificial radionuclides, a number of synthetic organic substances, certain acid-forming species, carbon dioxide and methane. These chemical changes in the atmosphere can often extend to the earth's soils, oceans, and biota far from the original source region. They can result in alterations in the earth's climate, changes in vital nutrient cycles, and impact significantly on the public health and quality of life on earth. The Atmosphere/Ocean Chemistry Experiment (AEROCE) will be a coordinated multi-institutional atmospheric and marine chemistry research project centered in the North Atlantic region. The ultimate goal of the AEROCE project will be the development of a predictive capability for the continentally derived species observed in the marine troposphere over the North Atlantic. The selection of sites and the measurement protocol in AEROCE has been developed jointly by modelers and field experimentalists. This AEROCE element will include a chemical study of aerosol and precipitation samples collected in the AEROCE network which will consist of four stations: Barbados; Bermuda-West; Mace Head, Ireland; Izania, Tenerife. The principal objectives are: (1) to characterize the major continentally-derived aerosol species and some related minor species that are present over the North Atlantic Ocean; (2) to study the temporal and areal variability in the concentration of these species in air; (3) to measure the concentration of these same species in precipitation; (4) on the basis of the concentration of these species in the air and in precipitation, to estimate the rate of deposition to the ocean; (5) in the case of selected trace metals, to measure the dissolved (or soluble fraction).