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Strong daytime production of OH from HNO 2 at a rural mountain site
Author(s) -
Acker Karin,
Möller Detlev,
Wieprecht Wolfgang,
Meixner Franz X.,
Bohn Birger,
Gilge Stefan,
PlassDülmer Christian,
Berresheim Harald
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl024643
Subject(s) - daytime , noon , nitrous acid , photodissociation , environmental science , atmospheric sciences , observatory , production rate , environmental chemistry , meteorology , chemistry , photochemistry , physics , inorganic chemistry , industrial engineering , astrophysics , engineering
Nitrous acid and OH were measured concurrently with a number of other atmospheric components and relevant photolysis frequencies during two campaigns at the Meteorological Observatory Hohenpeissenberg (980 m a.s.l.) in summer 2002 and 2004. On most of the 26 measurement days the HNO 2 concentration surprisingly showed a broad maximum around noon (on average 100 pptv) and much lower concentrations during the night (∼30 pptv). The results indicate a strong unknown daytime source of HNO 2 with a production rate on the order of 2–4 × 10 6 cm −3 s −1 . The data demonstrate an important contribution of HNO 2 to local HO x levels over the entire day, comparable with the photolysis of O 3 and HCHO. On average during the 2004 campaign, 42% of integrated photolytic HO x formation is attributable to HNO 2 photolysis.