Wuppertal 2015 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 3: EW 2/Space-Weather-2

EP 3.3: Talk

Tuesday, March 10, 2015, 09:00–09:15, G.10.02 (HS 9)

Solar influence on the MLT region: NOx production and global model studies — •Holger Nieder and Miriam Sinnhuber — Karlsruher Institut für Technologie

The chemistry in the mesosphere/lower thermosphere (MLT) region is driven by forcing from solar radiation and energetic particles. The resulting ionization, dissociation and excitation of the constituents lead to a variety of reactions as well as direct production of reactive species such as reactive nitrogen NOx (N, NO, NO2) and hydrogen HOx (H, OH, HO2). While the ions and HOx are short lived and disappear when the forcing is over, longer lived species such as NOx are subject to transport. Downward transported NOx causes Ozone depletion in the stratosphere, and there also affects atmospheric temperatures and circulation via radiative heating and cooling changes.

The production of atmospheric nitrogen compounds is investigated in detail. The dependence on ionization rate and background atmospheric state is quantitatively examined and made available for global 3d model studies. Results of the global studies as well as comparisons with measurements are presented and discussed. A good agreement between observed and modelled NOx is found as well as downwelling ozone anomalies of 15-60% in every winter.