PhD project "Constraining Terrestrial Biosphere Models Using Atmospheric Carbon Dioxide, Stable Carbon Isotope, and Radiocarbon Observations"
Max Planck Institute for Biogeochemistry
In cooperation with Friedrich Schiller University Jena (FSU), the Max Planck Institute for Biogeochemistry (MPI-BGC) houses a unique and flexible research program that grants German and foreign students a broad selection of learning opportunities while still maintaining a research focus. The International Max Planck Research School for Global Biogeochemical Cycles (IMPRS-gBGC) offers a PhD program specializing in global biogeochemistry and related Earth system sciences.
Homepage: https://www.bgc-jena.mpg.de/en/imprs
Biogeosciences (BG)
Climate: Past, Present & Future (CL)
Project description
Quantifying land-atmosphere carbon fluxes is a central challenge in Earth system science, with direct implications for climate prediction and mitigation policy (Canadell et al. 2021). Terrestrial biosphere models (TBMs) as part of comprehensive Earth System Models simulate key processes of land carbon fluxes and storage, yet their predictions often diverge significantly (Bastos et al 2020). Carbon isotopes (13CO2 and 14CO2) act like fingerprints of biospheric and anthropogenic carbon cycle processes, and offer an alternative yet underused data source to evaluate and constrain TBMs.
This PhD project will combine biosphere modelling with in-situ and atmospheric observations of carbon isotopes to reduce uncertainties in terrestrial carbon uptake and turnover. As a starting point, the PhD thesis will apply the global version of the QUINCY model (Thum et al. 2019), which is also used as part of the ICON climate model to provide climate projections for the 7th global climate model intercomparison project. QUINCY is one of the few TBMs globally that includes tracers as 13C and 14C. Simulated trends in atmospheric tracers-CO2 concentration, 13C, and radiocarbon (14C) - will be used to evaluate regional and global trends in carbon uptake and turnover and to evaluate their constraint on future trends on the land carbon balance.
Depending on the profile of the successful applicant, further steps of the thesis can include the further refinement of the isotope-enabled QUINCY model, further analysis of atmospheric trends using atmospheric transport models to simulate the large-scale distribution of these tracers of atmospheric trends, or the development and application of ensemble methods including machine learning to develop constraints for simulations of future developments. The outcome will be a better-constrained terrestrial carbon cycle and improved confidence in Earth system model projections under future climate scenarios.
This project offers cutting-edge expertise working with a world-leading Earth-system model that couples carbon, nitrogen, phosphorus, and isotopes, hands-on experience with using data from global observational networks (e.g., atmospheric CO2 stations, radiocarbon archives), advanced data-science toolbox including the use of high-performance computers, statistical model evaluation, and inverse modelling.
Working group & collaborations
The candidate will be part of the Biogeochemical Signals department and will have the opportunity to collaborate with researchers from multiple institutions in Germany (within the CAP7 project) and beyond.
Requirements for the PhD project are
Applications to the IMPRS-gBGC are open to well-motivated and highly-qualified students from all countries. Prerequisites for this PhD project are:
- Master's degree in bio(geo)chemistry, environmental science, geosciences, physics, atmospheric science, engineering, remote sensing or other disciplines related to environmental sciences.
- Background in terrestrial carbon cycle, and experience in ecosystem or atmosphere modelling
- Computational skills
- Experience with programming languages like R or python
- Knowledge of higher programming languages such as C or FORTRAN are an asset
- Experience with gridded datasets like ERA5 or similar
- Excellent oral and written communication skills in English
The Max Planck Society (MPS) strives for gender equality and diversity. The MPS seeks to increase the number of women in those areas where they are underrepresented and therefore explicitly encourages women to apply. The MPS is committed to increasing the number of individuals with disabilities in its workforce and therefore encourages applications from such qualified individuals.
References
QUINCY: https://www.bgc-jena.mpg.de/en/bsi/bsi-data/software/quincy-software
Bastos et al. (2020), Sources of uncertainty in regional and global terrestrial CO2 exchange estimates. Global Biogeochemical Cycles, 34, e2019GB006393. https://doi.org/10.1029/2019GB006393
Canadell et al. (2021): Global Carbon and other Biogeochemical Cycles and Feedbacks. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., et al. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 673–816, doi: 10.1017/9781009157896.007.
CAP7 Project: https://www.dwd.de/EN/research/projects/cap7/cap7_node.html
Thum, T., et al. (2019) A new model of the coupled carbon, nitrogen, and phosphorus cycles in the terrestrial biosphere (QUINCY v1.0; revision 1996), Geosci. Model Dev., 12, 4781–4802, https://doi.org/10.5194/gmd-12-4781-2019.
Your application consists of three steps:
- Online registration & submission of application documents (July 1 - August 6, 2026)
- (Possibly) Phone or video conference interview (August 2026)
- Selection symposium in Jena (October 5-6, 2026)