0000000000147149
AUTHOR
Rudolf Deckert
Global sensitivity of aviation NO<sub>x</sub> effects to the HNO<sub>3</sub>-forming channel of the HO<sub>2</sub> + NO reaction
Abstract. The impact of a recently proposed HNO3-forming channel of the HO2 + NO reaction on atmospheric ozone, methane and their precursors is assessed with the aim to investigate its effects on aviation NOx induced radiative forcing. The first part of the study addresses the differences in stratospheric and tropospheric HOx-NOx chemistry in general, by comparing a global climate simulation without the above reaction to two simulations with different rate coefficient parameterizations for HO2 + NO → HNO3. A possible enhancement of the reaction by humidity, as found by a laboratory study, particularly reduces the oxidation capacity of the atmosphere, increasing methane lifetime significantl…
A quasi chemistry-transport model mode for EMAC
Abstract. A quasi chemistry-transport model mode (QCTM) is presented for the numerical chemistry-climate simulation system ECHAM/MESSy Atmospheric Chemistry (EMAC). It allows for a quantification of chemical signals through suppression of any feedback between chemistry and dynamics. Noise would otherwise interfere too strongly. The signal is calculated from the difference of two QCTM simulations, a reference simulation and a sensitivity simulation. In order to avoid the feedbacks, the simulations adopt the following offline chemical fields: (a) offline mixing ratios of radiatively active substances enter the radiation scheme, (b) offline mixing ratios of nitric acid enter the scheme for re-…