Peroxy Radical Distribution During TOPSE and Implications for
Peroxy Radical Distribution During TOPSE and Implications for Ozone Photochemistry Christopher Cantrell and TOPSE Science Team Spring 2001 AGU Meeting
Outline • Description of CIMS peroxy radical measurements • Steady-state radical concentrations • Budgets of radicals and O 3 during TOPSE • Possible role of photochemistry in TOPSE O 3 trends Spring 2001 AGU Meeting
TOPSE in situ O 3 Spring 2001 AGU Meeting
TOPSE Steady State HO 2 + RO 2 Spring 2001 AGU Meeting
TOPSE Steady State OH Spring 2001 AGU Meeting
TOPSE Spring 2001 AGU Meeting 1 O( D)+H 2 O Rate
TOPSE Temperature Spring 2001 AGU Meeting
CIMS HO 2 and HO 2+RO 2 Measurements • Based on conversion of ambient peroxy radicals to gas-phase H 2 SO 4 – HO 2 + NO OH + NO 2 – OH + SO 2 (O 2, H 2 O, M) H 2 SO 4 • Chemical ionization – • Calibration – Photolysis of water vapor by 184. 9 nm radiation – Lamp flux by N 2 O actinometry Spring 2001 AGU Meeting
CIMS Inlets, rack, C 130 photos Spring 2001 AGU Meeting
Steady-State Radical Concentrations • Equation for each radical (OH, HO 2, CH 3 O 2) – • Assume d. X/dt << P or L, P-L 0 • n equations and n unknowns (radical concentrations) • Solve by iterative numerical method (Newton. Raphson). Requires initial estimate. • Use measured quantities (NOx, CO, NMHCs, O 3, jvalues, etc. ) when available in equations • Include HNO 4 chemistry (estimate of j. HNO 4) • Two calculations: effective CH 4, explicit treatment of NMHCs (and thus RO 2) Spring 2001 AGU Meeting
Comparison of measurements and steady-state HO 2+RO 2 Spring 2001 AGU Meeting
TOPSE Measured & SS HO 2+RO 2 Spring 2001 AGU Meeting
TOPSE SS Peroxy Radical Ratios Spring 2001 AGU Meeting
TOPSE HOx Production & Loss Spring 2001 AGU Meeting
TOPSE HOx Production Spring 2001 AGU Meeting
Steady State HO 2 NO 2 Spring 2001 AGU Meeting
TOPSE Net O 3 Production and Loss Spring 2001 AGU Meeting
TOPSE Net O 3 Production Spring 2001 AGU Meeting
TOPSE Net O 3 Production Spring 2001 AGU Meeting
Comparison with Other Studies Spring 2001 AGU Meeting
Acknowledgements • NCAR – ACD – RAF/ATD • • NSF TOPSE Colleagues Churchill Airport Thule Air Base Spring 2001 AGU Meeting
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