Comment on 'Observation and modelling of HOx radicals in a boreal forest' by Hens et al. (2014)

摘要

Though as a researcher one is always happy when peers find one's work useful and accordingly cite it, it is unfortunate when the respective paper is cited incorrectly. Hens et al. (2014) write "Studies on oxidation processes in monoterpene-dominated environments are rare. Direct OH reactivity measurements in a boreal forest, conducted by Sinha et al. (2008), and a box model study investigating the OH reactivity budget (Mogensen et al., 2011) revealed a significant fraction of ‘unknown OH reactivity'." Firstly, the reference of Sinha et al. (2008) must be an error, since that refers to a publication about the method development of the comparative reactivity method (CRM) together with first field tests conducted in the tropical rainforest of Suriname and the urban atmosphere of Mainz - but not in a boreal forest. We assume that Hens et al. (2014) instead are thinking of the paper by Sinha et al. (2010). Further, it is correct that Mogensen et al. (2011) found a large fraction of unaccounted OH reactivity; however, they did not reach that conclusion using a box model. Instead they presented the first model study of the total OH reactivity in a boreal forest using a one-dimensional column model with near-explicit chemistry (Boy et al., 2011; Mogensen et al., 2011). There exist earlier publications where the OH reactivity has been addressed using a 1-D model; for example, the OH loss has been simulated with respect to certain primary emitted organic compounds (e.g. Stroud et al., 2005).