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PhD student: Trends in stratospheric transport pathways and impacts on climate

Advertising institute: IEK-7 - Stratosphere
Reference number: D075/2014, Chemistry, Physics, Meteorology

For a research project at the Institute of Energy and Climate Research – Stratosphere, IEK-7, we are seeking a PhD student (Chemistry, Physics, Meteorology or equivalent degree) for a 3 year position for the earliest possible date.

Background
With 4400 staff members Forschungszentrum Jülich is the largest interdisciplinary research center in Germany focusing its research in the fields of health, environment and energy, and information technology. The upper troposphere and lower stratosphere (UTLS) is an atmospheric region, which is crucial for understanding climate change, because the Earth's radiation budget and surface temperatures sensitively depend on the trace gas composition in the UTLS. However, there is no scientific consensus regarding changes of different transport pathways in the UTLS in a changing climate (e.g., large-scale residual circulation, eddy mixing) and their role in controlling the UTLS trace gas composition. Thus, for reliable climate change predictions on seasonal to decadal time scales our understanding of the processes controlling the UTLS trace gas distribution needs to be improved.

Science and Experiments within the PhD thesis
Within this Ph.D. work, new model-based tools will be developed for improving our understanding of stratospheric transport pathways in a changing climate and related effects on trace gas composition and on surface temperatures. For this purpose, a unique model set-up will be used, namely the Lagrangian chemistry transport model CLaMS integrated into the Earth system model EMAC. The CLaMS-EMAC model combines the advantages of fully Lagrangian transport of atmospheric trace gases (in particular reduced numerical diffusion) with a comprehensive Earth system model, coupling atmosphere, ocean and land processes. To analyze the effects of changes in UTLS tracer composition, resulting from changes in transport pathways, on radiation and dynamics, a long-term CLaMS-EMAC simulation will be developed to include interactive chemistry for radiatively active species like H2O, O3, CH4, N2O, and CFCs. The simulated trace gas distributions will be thoroughly validated against measurements from satellite and from high-altitude aircraft based in-situ measurements. Finally, impacts of changes in long-lived tracers and in water vapor on temperatures (particularly at the surface) will be quantified. For the interpretation of transport changes, a new diagnostic tool will be implemented into the CLaMS-EMAC model for calculating the age spectrum of stratospheric air for non-stationary (time dependent) atmospheric flow.

This analysis goes beyond the state-of-the-art research and is expected leading to unprecedented insights into the relative strengths of different transport pathways and long-term circulation trends. It will further be of crucial relevance for climate model transport evaluation as it allows deficiencies in model transport to be detected, which are hidden with respect to current methods. Hence, this Ph.D. work is an important step towards improving our understanding of changes in transport processes in the UTLS region in a changing climate, and towards improving the representation of these processes in atmospheric models to improve climate predictions.

Tasks

  • Performing model simulations with the EMAC/CLaMS climate model system
  • Development of modules in fortran90 for EMAC/CLaMS
  • Statistical analysis and development of diagnostic tools for the assessment of model results of the EMAC/CLaMS model system and for comparison with observations

Requirements

  • M. Sc. (or equivalent) in physics, chemistry, meteorology, or a comparable field with a good final grade (in the German system 2.0 or better)
  • Very good programming skills
  • Experience in the analysis of complex data sets is advantageous
  • The ability to communicate research results in scientific publications and presentations at international conferences
  • A good command of the English language is required

We Offer

  • Working in a diverse international and motivated research team
  • Excellent technical support and access to supercomputing facilities
  • A well-organized PhD work including participation in the interdisciplinary HITEC graduate school on energy and climate research

For further information please contact:
Dr. Rolf Müller
Forschungszentrum Jülich
Institut für Energie- und Klimaforschung (IEK-7)
Leo-Brandt Straße
52425 Jülich

e-mail: ro.mueller@fz-juelich.de
Telefon: +49-2461-61-3828

Equal opportunity is a cornerstone of our staff policy. Applications from disabled persons are welcomed. Payment of the PhD fellow will be based on salary grade 13/2 Collective Agreement for the Civil Service (TVöD). Depending on the candidate's profile and the subject of his/her PhD thesis an additional allowance may be granted.

Please send your application – quoting the reference number - with the relevant documentation to:

Mr. K. Beumers
Institut für Bio- und Geowissenschaften
Forschungszentrum Jülich GmbH
52425 Jülich
Germany

e-mail: k.beumers@fz-juelich.de.


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