High resolution vertical distributions of NO3 and N2O5 through the nocturnal boundary layer S. S. Brown1, W. P. Dubé1,2, H. D. Osthoff1,2, D. E. Wolfe1, W. M. Angevine1,2, and A. R. Ravishankara1,3 1NOAA Earth System Research Laboratory, 325 Broadway, Boulder, CO 80305, USA 2Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80305, USA 3Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
Abstract. 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
NO3, N2O5 and O3 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 NO3 and N2O5 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 NO3 and N2O5 and
in the partitioning among nitrogen oxides between different near-surface
layers. These differences imply that NO3 and N2O5 occupy
distinct chemical regimes as a function of altitude, potentially serving as
sinks for nitrogen oxides and O3 near the surface but as reservoirs of
NOx and O3 aloft.
Citation: Brown, S. S., Dubé, W. P., Osthoff, H. D., Wolfe, D. E., Angevine, W. M., and Ravishankara, A. R.: High resolution vertical distributions of NO3 and N2O5 through the nocturnal boundary layer, Atmos. Chem. Phys., 7, 139-149, doi:10.5194/acp-7-139-2007, 2007.