High resolution vertical distributions of NO3 and N2O5 through the nocturnal boundary layer
Other literature type
Brown, S. S.
Dubé, W. P.
Osthoff, H. D.
Wolfe, D. E.
Angevine, W. M.
Ravishankara, A. R.
(issn: 1680-7324, eissn: 1680-7324)
The shallow mixing depth and vertical stratification of the lowest levels of
the atmosphere at night has implications for the chemistry of nitrogen
oxides emitted from the surface. Here we report vertical profiles of
NO<sub>3</sub>, N<sub>2</sub>O<sub>5</sub> and O<sub>3</sub> measured from in-situ instruments on a movable
carriage on a 300 m tower. The study offers high-resolution (<1 m)
vertical distributions of both NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> and shows that
the nocturnal mixing ratios of these compounds vary widely over short
vertical distance scales (10 m or less). Furthermore, there are systematic
differences in the steady state lifetimes of NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> and
in the partitioning among nitrogen oxides between different near-surface
layers. These differences imply that NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> occupy
distinct chemical regimes as a function of altitude, potentially serving as
sinks for nitrogen oxides and O<sub>3</sub> near the surface but as reservoirs of
NO<sub>x</sub> and O<sub>3</sub> aloft.