HR: 0830h
AN: A11F-0039    [PDF]
TI: Distribution of Reactive Nitrogen in the Sierra Nevada Foothills
AU: * Murphy, J G
EM: jgmurphy@uclink.berkeley.edu
AF: Department of Chemistry, University of California, Berkeley, CA 94720 United States
AU: Farmer, D K
EM: dfarmer@nature.berkeley.edu
AF: Department of Chemistry, University of California, Berkeley, CA 94720 United States
AU: Wooldridge, P J
EM: pjwool@socrates.berkeley.edu
AF: Department of Chemistry, University of California, Berkeley, CA 94720 United States
AU: Cohen, R C
EM: cohen@cchem.berkeley.edu
AF: Department of Chemistry, University of California, Berkeley, CA 94720 United States
AU: Cohen, R C
EM: cohen@cchem.berkeley.edu
AF: Division of Energy and Environmental Tecnologies, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 United States
AB: Nitrogen oxides can exert regional influence over areas downwind by governing photochemical ozone production and by contributing to nitrogen deposition in ecosystems. The Sierra Nevada mountain counties routinely exceed national ozone standards and atmospheric nitrogen deposition has been identified as a potential cause of the declining water clarity of Lake Tahoe. Thermal dissociation laser-induced fluorescence (TD-LIF) was used to make continuous, high time resolution observations of NO$_{2}$, total peroxy nitrates ($\Sigma$PNs), total alkyl nitrates ($\Sigma$ANs ), and HNO$_{3}$ at two sites in the Sierra Nevada foothills. This is the fourth year of measurements by TD-LIF at the Blodgett Forest Research station (38.90$\deg$N, 120.63$\deg$W, 1315 m asl). Measurements began at Big Hill, 30 miles to the east (38.85$\deg$N and 120.42$\deg$W, 1850 m asl), in spring of 2003 as part of the Lake Tahoe Atmospheric Deposition Study. The abundance and partitioning of the reactive nitrogen species, NO$_{2}$, $\Sigma$PNs, $\Sigma$ANs, and HNO$_{3}$, over several months at the two sites are compared. The Blodgett Forest site is subjected to a regular daily pattern of mountain-valley flow, whereas the site at Big Hill is exposed to a wider range of synoptic weather patterns. The similarities and differences between the diurnal profiles and absolute amounts of reactive nitrogen species at the two sites allow us to begin to examine the complex interplay between transport and chemistry that governs the distribution of nitrogen species in the boundary layer.
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting