Watox‐86 overview and western North Atlantic Ocean S and N atmospheric budgets

Abstract

This paper is an overview of an intensive period of data collection performed as part of the Western Atlantic Ocean Experiment (WATOX) during early 1986. The objective of WATOX‐86 was to determine the flux and fate of a variety of atmospheric materials that are advected eastward from North America to the atmosphere of the western North Atlantic Ocean (WNAO). WATOX‐86 used two National Oceanic and Atmospheric Administration aircraft, a twin engine King Air and a four engine WP‐3D, to collect gases and aerosols off the east coast of North America from Florida to Newfoundland. The WP‐3D was based at McGuire Air Force Base, New Jersey, during the first 10 days of January 1986. The King Air was based at Hanscom Field, Massachusetts, during periods in January and February 1986 and on Bermuda during May 1986. Measurements were made of a variety of gases including SO2, NOx, NOy, peroxyacetyl nitrate, CO, O3, C2−C6 hydrocarbons, N2O and dimethyl sulfide. In addition, aerosols were collected and analyzed for black carbon, SO4=, NO3−, NH4+ and trace metals. The individual papers of this special issue provide details on the results and analysis of the individual measurement programs. This paper provides a brief summary of each program. During WATOX‐86, there were large regions of the WNAO atmosphere that had elevated concentrations of the measured gas and aerosol species. The elevated concentrations were the result of transport of the products of anthropogenic activities from North America to the WNAO atmosphere. The high degree of correlation among the concentrations of the different species indicated that these materials were transported in “clouds” of polluted air that covered thousands of square kilometers. The WATOX‐86 data on sulfur and nitrogen oxides are analyzed in the context of atmospheric budgets for WNAO. Approximately 25 to 35% of the sulfur and 15 to 25% of the nitrogen oxides emitted to the eastern North American atmosphere are advected eastward to the WNAO atmosphere. Of this material, about half of the sulfur and most of the nitrogen oxides are deposited to the WNAO. For both sulfur and nitrogen oxides, wet and dry deposition are of approximately equal importance.