ECHAM5 simulations with the HO2 + NO → HNO3 reaction

Abstract

A HNO3-forming channel of the HO2 + NO reaction recently found in laboratory measurements (Butkovskaya et al., 2005, 2007) may significantly alter the concentration of HNO3, NOx, O3 and other trace gases in the tropopause region. This region is also significantly affected by air traffic NOx emissions. Cariolle et al. (2008) adopted a pressure- and temperature dependent parameterisation of the rate constant to assess the impact of the HO2 + NO -> HNO3 reaction on trace gas concentrations in a 2-D stratosphere-troposphere model, and a 3-D tropospheric chemical transport model. We implemented the parameterisation of Cariolle et al. (2008) into the 3-D stratosphere- troposphere chemistry-climate model ECHAM5 / MESSy. Here we present results of our test runs, in support of planned studies of the effects of aircraft emissions on atmospheric chemistry.