D. Jaffe et al., Observations of ozone and related species in the northeast Pacific during the PHOBEA campaigns 1. Ground-based observations at Cheeka Peak, J GEO RES-A, 106(D7), 2001, pp. 7449-7461
As part of the Photochemical Ozone Budget of the Eastern North Pacific Atmo
sphere (PHOBEA) project, we made observations of CO, O3, NOx, peroxyacetyl
nitrate (PAN), nonmethane hydrocarbons (NMHC), Rn, aerosol scattering, aero
sol absorption, and aerosol number density during the springs of 1997 and 1
998 at the Cheeka Peak Observatory (CPO) on the western tip of Washington S
tate. The data have been segregated to quantify the mixing ratio of these s
pecies in the Pacific marine atmosphere. However, even in these marine air
masses, there are occasionally substantial enhancements of NOx and aerosols
, but not CO, which we attribute to diesel exhaust from ship traffic to and
from major ports in the region. The marine air masses were further classif
ied into four categories based on 10-day back isentropic trajectories; high
, mid, and low latitude and those which had crossed over the Asian industri
al region. Mean marine mixing ratios in 1998 were significantly higher then
the 1997 values for CO (1997 mean equal to 151, 1998 mean equal to 170 ppb
v), ethane (1771, 1968 parts per trillion by volume (pptv)), and ethyne (30
6, 452 pptv). Also, segregation of the 1998 data by air mass origin produce
d smaller differences in the mixing ratios for most species when comparing
different source regions. We attribute both of these results to elevated em
issions associated with unusually large areas of biomass burning which took
place in Indonesia and Siberia during late 1997 and 1998. The relative enh
ancements of CO, ethane, ethyne, and propane we observed at CPO are consist
ent with enhanced biomass burning and industrial sources in the spring of 1
998, relative to the spring of 1997.