SAPHIR: description and transnational access

1. Introduction

The large atmospheric simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) in Jülich is a tool for the quantitative experimental investigation of tropospheric chemistry under natural conditions and for the evaluation of photochemical models. The ultimate goal is the experimental verification of the chemistry of tropospheric trace compounds. SAPHIR is part of the Transnational Access of Euochamp-2.

2. Description of the research facility

SAPHIR provides a platform for quantitative, experimental verification and improvement of photochemical models at realistic concentrations and solar radiation. The results from the simulation experiment will be incorporated in models for atmospheric research which help to predict human influence on the atmosphere. Moreover, a direct comparison of field and simulation experiments is possible. SAPHIR provides an international platform for basic research and measurement intercomparisons. The following questions are addressed:

• What are the precursors and physical parameters determining the concentration radicals?
• How do parameters influence the degradation of important trace substances?
• What drives the formation and degradation of photooxidants?
• Which factors influence the formation and properties of particles?
• Which parameters affect the quality and reliability of atmospheric measurements?

The specific characteristics of SAPHIR are:

• Simulation of tropospheric photo chemistry under natural conditions.
• Multiple equipment for trace gas and aerosol measurements.
• Direct measurements of radicals, i.e.OH, HO₂, RO₂, and NO₃.
• Access for field instruments / containers.
• Versatile platform for intercomparisons of instruments.

In the atmosphere simulation chamber it is possible to simulate the photochemistry of the troposphere under natural conditions. Interferences such as transport processes or unquantifiable sources and sinks of individual trace gases can be avoided. Since the chamber can be flooded with air of a selectable composition, the scientists have a set of advantages over measurements in the outside air. E.g. Nonlinear correlations can be systematically investigated over the large, naturally occurring concentration range of trace gases. In addition the impact of future trace and pollutant gases or of emission reduction strategies on the chemistry of the troposphere can be studied.

2.1. Technical data

A double-walled Teflon foil forms the boundary of the tubular chamber with a capacity of roughly 270m³. This material is permeable to the sun's UV radiation which supplies the energy required for all the chemical reactions taking place in the chamber. Teflon is chemically inert, which means that it does not react with trace gases. The interspace of the double wall is constantly purged with ultraclean gases so that the adjusted chamber atmosphere does not inadvertently mix with the outside air.

The sun serves as a natural light source. A louvre system permits chemical reactions of the air to be also analysed in the dark or under different light conditions. The photolysis rates inside the chamber can be precisely calculated from outside radiometer measurments.

2.2. Images

2.3. Publications

A detailed list of publications is provided here.

2.4. Access to the chamber under Eurochamp TA

Access to SAPHIR is provided through Eurochamp-2 Transnational Acces and other collaborations. Please contact us find the appropriate setup for new projects at SAPHIR.

SAPHIR offers access to various types of instruments. These instruments can be placed next to the chamber floor inside of containers (e.g. see the experimental sections of Schlosser et al. 2009 and Apel et al. 2008 for details). Modifications of inlet lines or flanges can be provided on request. Access to workshops and laboratories can be provided after consultation. Status data of the chamber and the data of the installed instruments are available for the user.

3. Institution in charge of the laboratory facility

The Institute for Chemistry and Dynamics of the Geosphere (ICG) at Forschungszentrum Jülich (FZJ) is integrated in the "programmorientierte Förderung (PoF)" (Programme Oriented Funding) of the "Helmholtz-Gemeinschaft Deutscher Forschungszentren" (HGF). Together with the Research Centre Karlsruhe (FZK) and the German National Research Centre for Geosciences (GFZ) the ICG-1 (Stratosphere) and ICG-2 (Troposphere) form the main focus in the programme "Atmosphere and Climate" in the research field "Earth and Environment".

FZJ is partner 2 in Eurochamp-2.

3.1. Contact Information

 Prof. Andreas Wahner, phone: +49 24 61 61 46 92

 Dr. Theo Brauers, phone: +49 24 61 61 66 46

Forschungszentrum Jülich
Institute for Energy and Climate Research, Troposphere (IEK-8)
D-52425 Jülich, Germany

4. Additional Information

n.a.