Open AccessPeroxy radical and related trace gas measurements in the boundary layer above the Atlantic Ocean
Author(s) -
Burkert Jörn,
AndrésHernández MariaDolores,
Stöbener Dirk,
Burrows John Philip,
Weissenmayer Michael,
Kraus Alexander
Publication year - 2001
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd900613
Subject(s) - trace gas , troposphere , tropical atlantic , mixing ratio , environmental science , air mass (solar energy) , atmospheric sciences , hydroperoxyl , microwave limb sounder , stratosphere , noon , boundary layer , meteorology , oceanography , radical , chemistry , geology , sea surface temperature , physics , organic chemistry , thermodynamics
Measurements of peroxy radicals (RO 2 * = HO 2 + ∑RO 2 , where HO 2 is the hydroperoxyl radical and R is an organic group) were made using the chemical amplifier technique (PERCA) during the Air chemistry and Lidar studies of tropospheric and stratospheric species on the Atlantic Ocean (ALBATROSS) campaign on board the German research vessel Polarstern (cruise ANT XIV/1, 1996). The data obtained are compared to previous results from an earlier cruise in 1991 (ANT X/1). Reasonable agreement between the two data sets was observed, indicating the reliability of these measurements. Both data sets take into account the sensitivity of the radical amplifier to the presence of ambient water vapor. Maximum RO 2 * mixing ratios around noon between 40 and 80 pptv were measured. Nighttime signals were observed on many days. Air masses in different latitude regions in the North and South Atlantic could be characterized using back trajectories. In spite of the fact that the RO 2 * is relatively short lived, its mixing ratio appears to be influenced by the path traveled by the air mass somewhat higher levels being associated with sources of pollution. A box model based on CH 4 and CO oxidation chemistry describes RO 2 * reasonably well but could not explain the persistent nighttime signals and the HCHO observed. An additional source of HCHO is required, indicating the importance of nonmethane hydrocarbon (NMHC) chemistry in the remote Atlantic boundary layer. Both back trajectories and variations of trace gas concentrations indicate that biomass burning, ship, and natural emissions are likely responsible for the observed deviations from the assumed chemistry.