Intercontinental transport of pollution manifested in the variability and seasonal trend of springtime O3 at northern middle and high latitudes

Authors

Yuhang Wang, Georgia Institute of Technology - Main Campus
Changsub Shim, Georgia Institute of Technology - Main Campus
Nicola J. Blake, University of California, IrvineFollow
D R. Blake, University of California, Irvine
Yunsoo Choi, Georgia Institute of Technology - Main Campus
Brian Ridley, NCAR
Jack E. Dibb, University of New HampshireFollow
Anthony Wimmers, University of Virginia - Main Campus
Jennie Moody, University of Virginia - Main Campus
F Flocke, National Center for Atmospheric Research
Andrew Weinheimer, National Center for Atmospheric Research
R. Talbot, University of New HampshireFollow
Elliot Atlas, NCARFollow

Abstract

Observations (0–8 km) from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiment are analyzed to examine air masses contributing to the observed variability of springtime O₃ and its seasonal increase at 40°–85°N over North America. Factor analysis using the positive matrix factorization and principal component analysis methods is applied to the data set with 14 chemical tracers (O₃, NO_y, PAN, CO, CH₄, C₂H₂, C₃H₈, CH₃Cl, CH₃Br, C₂Cl₄, CFC-11, HCFC-141B, Halon-1211, and ⁷Be) and one dynamic tracer (potential temperature). Our analysis results are biased by the measurements at 5–8 km (70% of the data) due to the availability of ⁷Be measurements. The identified tracer characteristics for seven factors are generally consistent with the geographical origins derived from their 10 day back trajectories. Stratospherically influenced air accounts for 14 ppbv (35–40%) of the observed O₃ variability for data with O₃concentrations <100 ppbv at middle and high latitudes. It accounts for about 2.5 ppbv/month (40%) of the seasonal O₃ trend at midlatitudes but for only 0.8 ppbv/month (<20%) at high latitudes, likely reflecting more vigorous midlatitude dynamical systems in spring. At midlatitudes, reactive nitrogen-rich air masses transported through Asia are much more significant (11 ppbv in variability and 3.5 ppbv/month in trend) than other tropospheric contributors. At high latitudes the O₃ variability is significantly influenced by air masses transported from lower latitudes (11 ppbv), which are poor in reactive nitrogen. The O₃ trend, in contrast, is largely defined by air masses rich in reactive nitrogen transported through Asia and Europe across the Pacific or the Arctic (3 ppbv/month). The influence from the stratospheric source is more apparent at 6–8 km, while the effect of O₃ production and transport within the troposphere is more apparent at lower altitudes. The overall effect of tropospheric photochemical production, through long-range transport, on the observed O₃ variability and its seasonal trend is more important at high latitudes relative to more photochemically active midlatitudes.

Department

Earth Sciences, Earth Systems Research Center

Publication Date

11-16-2003

Journal Title

Journal of Geophysical Research

Publisher

Wiley

Digital Object Identifier (DOI)

10.1029/2003JD003592

Document Type

Article

Recommended Citation

Wang, Y., et al. (2003), Intercontinental transport of pollution manifested in the variability and seasonal trend of springtime O3 at northern middle and high latitudes, J. Geophys. Res., 108, 4683, doi:10.1029/2003JD003592, D21.

Rights

Copyright 2003 by the American Geophysical Union.