J. Zheng et al., ANALYSIS OF SMALL-SCALE AND LARGE-SCALE INCREASES OF REACTIVE NITROGEN OBSERVED DURING THE 2ND AIRBORNE ARCTIC STRATOSPHERIC EXPEDITION, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 101(D22), 1996, pp. 28805-28816
An analysis of the data obtained during AASE II was made to characteri
ze small- (delta x < 24 km) and large-scale (30 < delta x < 260 km) in
creases of reactive nitrogen species. By using the NOx/NOy ratio, the
increases were classified into fresh emissions and aged air parcels. T
he sources of the NOy increases were then assessed by the freshness of
the increases and by examining the correlation (or absence thereof) b
etween NOy and other trace species including tracers of various NOx so
urces: for example, aircraft emissions, lightning, the stratospheric s
ource, and sources in the boundary layer. We found that the majority (
43%) of NOy increases in the upper troposphere and lower stratosphere
were due to displacement of constant mixing ratio surfaces relative to
isobaric flight paths. Aircraft emissions were the second most abunda
nt (17%). The next significant contributor was surface emissions, incl
uding fossil fuel combustion and biomass burning. Only two lightning s
pikes were found, apparently due to the winter season and emphasis on
high latitudes in the AASE II experiment. The relative contribution fr
om each source to the increases (or positive variability) represents a
measure of the relative source strength. However, it is important to
note that our findings on the relative contribution of each source to
the NOy increases should not be applied directly to estimating the rel
ative source strength of the ambient or background NOy abundance. Know
ledge of the detailed temporal and spatial distribution of the relativ
e contribution of each source is needed. This requires a substantially
higher precision for the instruments of tracer gases than those used
in this study.