Ship-based nitric acid measurements in the Gulf of Maine during New England Air Quality Study 2002

Authors

Jack E. Dibb, University of New HampshireFollow
Eric Scheuer, University of New Hampshire - Main CampusFollow
Sallie I. Whitlow, University of New Hampshire - Main Campus
Marcy Vozzella, University of New Hampshire - Main Campus
Eric Williams, NOAA
Brian M. Lerner, University of Colorado Boulder

Abstract

Gas phase nitric acid (HNO₃) was measured at 5-min resolution on board the National Oceanographic and Atmospheric Administration (NOAA) research vessel Ronald H. Brown during the second leg (29 July to 10 August) of the New England Air Quality Study (NEAQS) 2002 cruise. A primary objective of the cruise was to improve understanding of the oxidation of NO_x in, and removal of the oxidation products from, the polluted marine boundary layer east of northeastern North America. For the first 9 days of this leg the ship remained north of Cape Cod, and the cruise track did not extend much farther north than the New Hampshire-Maine border. During this period, HNO₃ averaged 1.1 ppb and accounted for 19% of total reactive nitrogen oxides (measured NO_y). On all days, peak HNO₃ mixing ratios were observed in the early afternoon (average 2.3 ppb), at levels twofold to fourfold higher than the minima around sunrise and sunset. In these daytime peaks, HNO₃/NO_y averaged 28%. There were secondary nighttime peaks of HNO₃ (0.9 ppb average), when HNO₃ accounted for 16% of total reactive nitrogen oxides. This pronounced diurnal pattern confirms that production, and subsequent deposition, of HNO₃ in the polluted marine boundary layer downwind of New England removes a significant fraction of the NO_x exported to the atmosphere over the Gulf of Maine. Nitric acid was correlated with O₃, particularly during the early afternoon interval when both molecules reached maximum mixing ratios (R² = 0.66). The ozone production efficiency (OPE) inferred from the slope (10 ppb O₃/ppb HNO₃) was similar to the OPE of 9 estimated at the Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) Thompson Farm station in coastal New Hampshire during the study period.

Department

Earth Sciences, Earth Systems Research Center

Publication Date

10-27-2004

Journal Title

Journal of Geophysical Research

Publisher

Wiley

Digital Object Identifier (DOI)

10.1029/2004JD004843

Document Type

Article

Recommended Citation

Dibb, J. E., E. Scheuer, S. I. Whitlow, M. Vozella, E. Williams, and B. M. Lerner (2004), Ship-based nitric acid measurements in the Gulf of Maine during New England Air Quality Study 2002, J. Geophys. Res., 109, D20303, doi:10.1029/2004JD004843.

Rights

Copyright 2004 by the American Geophysical Union.