R. F. Hansen
Indiana University Bloomington
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Featured researches published by R. F. Hansen.
Journal of Geophysical Research | 2016
Stephen M. Griffith; R. F. Hansen; S. Dusanter; Vincent Michoud; J. B. Gilman; William C. Kuster; P. R. Veres; Martin Graus; J. A. de Gouw; James M. Roberts; Cora J. Young; Rebecca A. Washenfelder; Steven S. Brown; Ryan Thalman; Eleanor M. Waxman; R. Volkamer; Catalina Tsai; J. Stutz; James Flynn; N. Grossberg; Barry Lefer; S. Alvarez; Bernhard Rappenglueck; Levi H Mielke; Hans D. Osthoff; Philip S. Stevens
Measurements of hydroxyl (OH) and hydroperoxy (HO2*) radical concentrations were made at the Pasadena ground site during the CalNex-LA 2010 campaign using the laser-induced fluorescence-fluorescence assay by gas expansion technique. The measured concentrations of OH and HO2* exhibited a distinct weekend effect, with higher radical concentrations observed on the weekends corresponding to lower levels of nitrogen oxides (NOx). The radical measurements were compared to results from a zero-dimensional model using the Regional Atmospheric Chemical Mechanism-2 constrained by NOx and other measured trace gases. The chemical model overpredicted measured OH concentrations during the weekends by a factor of approximately 1.4 ± 0.3 (1σ), but the agreement was better during the weekdays (ratio of 1.0 ± 0.2). Model predicted HO2* concentrations underpredicted by a factor of 1.3 ± 0.2 on the weekends, while measured weekday concentrations were underpredicted by a factor of 3.0 ± 0.5. However, increasing the modeled OH reactivity to match the measured total OH reactivity improved the overall agreement for both OH and HO2* on all days. A radical budget analysis suggests that photolysis of carbonyls and formaldehyde together accounted for approximately 40% of radical initiation with photolysis of nitrous acid accounting for 30% at the measurement height and ozone photolysis contributing less than 20%. An analysis of the ozone production sensitivity reveals that during the week, ozone production was limited by volatile organic compounds throughout the day during the campaign but NOx limited during the afternoon on the weekends.
Atmospheric Chemistry and Physics | 2012
A. M. Bryan; Steven B. Bertman; Mary Anne Carroll; S. Dusanter; G. D. Edwards; Renate Forkel; Stephen M. Griffith; Alex Guenther; R. F. Hansen; Detlev Helmig; B. T. Jobson; Frank N. Keutsch; Barry Lefer; Shelley Pressley; Paul B. Shepson; Philip S. Stevens; Allison L. Steiner
Atmospheric Chemistry and Physics | 2012
Stephen M. Griffith; R. F. Hansen; S. Dusanter; Philip S. Stevens; M. Alaghmand; S. B. Bertman; Mary Anne Carroll; M. Erickson; M. M. Galloway; N. Grossberg; John Robert Hottle; J. Hou; B. T. Jobson; Aster E Kammrath; Frank N. Keutsch; Barry Lefer; Levi H Mielke; A. O'Brien; Paul B. Shepson; M. Thurlow; W. Wallace; N. Zhang; X. Zhou
Atmospheric Chemistry and Physics | 2013
R. F. Hansen; Stephen M. Griffith; S. Dusanter; P. S. Rickly; Philip S. Stevens; S. B. Bertman; Mary Anne Carroll; M. H. Erickson; James Flynn; N. Grossberg; B. T. Jobson; Barry Lefer; H. W. Wallace
Atmospheric Measurement Techniques | 2015
Vincent Michoud; R. F. Hansen; Nadine Locoge; Philip S. Stevens; S. Dusanter
Atmospheric Environment | 2012
M. M. Galloway; Joshua Digangi; John Robert Hottle; Andrew J. Huisman; Levi H Mielke; M. Alaghmand; Paul B. Shepson; Joanna Weremijewicz; Hugh Klavon; Fredrick M. McNeal; Mary Anne Carroll; Stephen M. Griffith; R. F. Hansen; S. Dusanter; Philip S. Stevens; Steven B. Bertman; Frank N. Keutsch
Atmospheric Chemistry and Physics | 2016
Benjamin C. Schulze; H. W. Wallace; James Flynn; Barry Lefer; M. H. Erickson; B. Tom Jobson; S. Dusanter; Stephen M. Griffith; R. F. Hansen; Philip S. Stevens; Timothy M. VanReken; Robert J. Griffin
Archive | 2009
Levi H Mielke; Jonathan H. Slade; M. Alaghmand; Stephen Bertman; Mary Anne Carroll; Steve Griffith; R. F. Hansen; S. Dusanter; Paul Stevens; Armin Hansel; Paul B. Shepson
Journal of Geophysical Research | 2016
Stephen M. Griffith; R. F. Hansen; S. Dusanter; Vincent Michoud; J. B. Gilman; William C. Kuster; P. R. Veres; Martin Graus; J. A. de Gouw; James M. Roberts; Cora J. Young; Rebecca A. Washenfelder; Steven S. Brown; Ryan Thalman; Eleanor M. Waxman; R. Volkamer; Catalina Tsai; J. Stutz; James Flynn; N. Grossberg; Barry Lefer; S. Alvarez; Bernhard Rappenglueck; Levi H Mielke; Hans D. Osthoff; Philip S. Stevens
Atmospheric Measurement Techniques Discussions | 2015
Vincent Michoud; R. F. Hansen; Nadine Locoge; Philip S. Stevens; S. Dusanter