skip to content


Topic 5: Chemistry-climate interactions on global to regional scales

Project description: REKLIM+ is part of the project "REgionale KLIMaänderungen" (regional climate change), launched by the Helmholtz Association. The research is designed in close cooperation with the Institutes IEK-7 and -8 of the Research Centre Jülich. The Rhenish Institute for Environmental Research (RIU) at the University of Cologne is included in the 5th topic team (“Atmospheric composition and climate: interactions from global to regional scales”) of the REKLIM+ project.

The main goal of this topic is to understand the impact of global climate variations on regional scale and the potential of feedback effects in order to make reliable predictions on human health consequences from regional climate change, especially in urban and metropolitan areas. Here, specific scientific and technical challenges are the development of coupled models, the parameterization of aerosol and cloud processes, the evaluation of different data sources (ground stations, aircraft, satellites) to provide relevant information for this topic and evaluate the models, as well as the determination of emission strenghts from these data. This last goal is addressed by RIU aiming to quantitatively estimate anthropogenic and biogenic emission patterns and to understand their impact on the atmosphere.

Emissions can promote changes in the source area but also along airsheds. For instance, the influence of urban area emissions can be local (urban air pollution, heat islands), regional (regional air pollution, dry and wet precipitation) or potentially global (long range transport and vertical transport into the upper troposphere – lower stratosphere levels). Moreover, emissions that are emitted by plants include Biogenic Volatile Organic Compounds (BVOCs) are oxidized in the troposphere and form Secondary Organic Aerosols (SOA), which are transported though the atmosphere. In this way, air pollutant concentrations are induced by emission sources and will possibly impact the global radiation budget. The challenge in this research field is to find out the production way of these processes and the strength of the emission sources. As a first focus, the aim of the research is to estimate emissions of anthropogenic origin, using Inverse Modeling techniques. This is usefull to get the quantitative analysis of emissions and the chemical conversions of the emitted species in the surface layer and above, as well as to understand exchange processes. As a second focus, the emissions produced by the biosphere are examined.

Methodology: By its advanced data assimilation module the EURAD-IM model system provides techniques to combine observations and statistical information. The quantification of updrafts by assimilation is planned in collaboration with the IEK-7 of the Research Centre Jülich, with the focus placed on the radiance assimilation of GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) tomographic viewing geometry that scans air columns with high resolution. Moreover, disaggregation and aggregation of the emissions is accomplished using GIS techniques. All the computationally demanding processes are performed on high performance computers of JRC at the Research Centre Jülich, ensuring that high resolution and local analysis can be achieved. The PEGASOS flight campaign provides special data for the completion of this work.