PhD position - Variability in the stratospheric circulation in reanalysis and climate models

Jülich Research Centre (FZJ)

Jülich, Germany

Work group:

IEK-7 – Stratosphäre



Area of research:

PHD Thesis



Job description:

The Institute of Energy and Climate Research – Stratosphere (IEK-7) conducts research on the chemistry, dynamics and microphysics of the stratosphere and the tropopause region, and on the role these atmospheric layers play in the climate system.The global stratospheric Brewer-Dobson circulation is a key control factor for the composition of the lower stratosphere with radiatively active trace gases and hence changes in the circulation crucially affect the global radiation budget. While current climate models simulate an accelerating circulation due to climate change, stratospheric measurements of the mean age of air, the average transit time for transport through the stratosphere, indicate a slow-down of the circulation. Therefore, the representation of potential changes in the stratospheric circulation in atmospheric models is a major uncertainty for climate predictions. In particular, newest generation meteorological reanalysis data sets show very different stratospheric circulation changes on decadal timescales, emphasizing the current lack of knowledge on stratospheric circulation changes. The aim of the work is to investigate the dynamical causes for changes of the stratospheric Brewer- Dobson circulation in a changing climate in current generation meteorological reanalysis data sets and climate models, and the induced effects on the trace gas composition in the lower stratosphere.


Your Job:


The dynamical causes for stratospheric circulation changes will be analyzed by calculating the wavedrag forcing of the circulation, separated into contributions from different wave components (e.g.,planetary, synoptic scale and gravity waves). Differences in circulation variability between currentgeneration reanalyses (ERA-Interim, MERRA-2, JRA-55, ERA-5), and between reanalyses and the EMAC climate model will be analyzed, in particular for potential model deficits in the representation of decadal variability and changes in the stratospheric circulation. The newly developed EMAC model version with Lagrangian transport (EMAC-CLaMS) will be analyzed for feedback effects of the trace gas transport scheme on dynamics and to what extend Lagrangian transport could improve the representation of the stratospheric circulation in climate models.Your tasks in detail:



  • Calculate wave drag for different reanalyses and climate model simulations

  • Separate the contributions of different wave types (e.g., Fourier decomposition)

  • Analyze variability (e.g., seasonality, Quasi-Biennial Oscillation, El Nino Southern

  • Oscillation) on stratospheric circulation, wave drag, and trace gas composition

  • Carry out new EMAC climate model simulations with improved Lagrangian CLaMS

  • transport and analyze improvements in the representation of the stratospheric circulation

  • Presentation of results at national and international conferences

  • Writing publications

  • Close cooperation with other research groups

Your Profile:

  • Master degree in physics, chemistry, atmospheric sciences or a related field (e.g. computer science, mathematics) with good final grade (German system equivalent 2.0 or better)
  • Very good numerical and programming skills are essential; knowledge of Fortran is an advantage
  • Experience in scientific computing on high performance computers is of advantage
  • Experience with Python and IDL plotting software and with a Linux environment is of advantage
  • Good skills in the spoken and written English language

Our Offer:

  • Outstanding scientific and technical infrastructure – ideal conditions for successfully completing a doctoral degree
  • A highly motivated group as well as an international and interdisciplinary working environment at one of Europe’s largest research Establishments
  • Chance of participating in (international) conferences
  • Broad spectrum of training in the Graduate School HITEC www.hitec-graduate-school.de and the Forschungszentrum
  • Participation in overarching seminars including certificate
  • Continuous, professional support by your scientific Supervisor
  • Usually a contract for the duration of 3 years
  • Pay in line with 67,5 % of pay group 13 of the Collective Agreement for the Public Service (TVöD-Bund).
  • Information on employment as a PhD student at Forschungszentrum Jülich can be found here www.fz-juelich.de/gp/Careers_Docs

Forschungszentrum Jülich aims to employ more women in this area and therefore particulary welcomes applications from women.We also welcome applications from disabled persons.


Please apply via recruiter’s website.

Quote Reference: 2019D-229

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