Photochemical oxidant formation over southern Switzerland: 2. Model results

Citations Over TimeTop 12% of 1997 papers

Abstract

Measurements of photooxidants made during summer 1994 in the southern part of Switzerland are compared with results of a one‐dimensional Lagrangian model. The agreement between modeled and measured ozone concentrations is good. Concentrations of highly soluble species such as H 2 O 2 and HNO 3 are overestimated by the model. The model underestimates concentrations of isoprene, HCHO, and HONO. The impact of this discrepancy on the question of NO x versus VOC limitation of the ozone production is discussed. According to the model, reduction of the NO x emissions is more effective in reducing O 3 than reduction of the VOC emissions for a large fraction of the area under investigation. This finding is in accordance with what we concluded from the data. The southern part of Switzerland is often impacted by a plume originating from Milan, which leads to additional ozone at the measuring site. We used the model to simulate the influence of this plume on the chemical regime. The plume emissions are picked up by the model at two different times. Both cases deliver the same concentrations for the end point of the calculations. If the emissions are picked up early in the morning, the ozone production becomes VOC sensitive for a few hours before switching back to being NO x sensitive. If the emissions are picked up later, the O 3 production stays NO x sensitive all the time. Forcing the model to reproduce measured concentrations of HONO and isoprene shifts the O 3 production toward being more NO x sensitive.

Related Papers

• → The tropospheric degradation of isoprene: an updated module for the regional atmospheric chemistry mechanism(2003)138 cited
• → Sensitivity of biogenic isoprene emissions to past, present, and future environmental conditions and implications for atmospheric chemistry(2012)129 cited
• → Interaction between a bubble plume and the near field in a stratified lake(2004)105 cited
• → Thermal-image-derived dynamics of vertical ash plumes at Santiaguito volcano, Guatemala(2009)34 cited
• Subsurface oil release field experiment - observations and modelling of subsurface plume behaviour(1996)