Early Stage Researcher PhD position, Innovative Training Network “S2S-FUTURE”: modeling grain size distributions in rivers

Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences

Potsdam, , DE

The Helmholtz Centre Potsdam –  GFZ German Research Centre for Geosciences is the national research centre for Earth sciences in Germany. With approximately 1.280 employees (including visiting scientists), the GFZ is conducting interdisciplinary research on the “System Earth” and the influence of humans on the planet. As a member of the Helmholtz Association, it is part of Germany’s largest science organization.
Within the GFZ, the Earth Surface Process Modeling Section specializes in the development of computer models to simulate the processes responsible for the evolution of the Earth’s surface, such as bedrock incision by rivers and glaciers in mountain ranges, or the slow weathering of rock in low relief continental interiors. In doing so, we provide a framework to integrate field observations and laboratory measurements, and make predictions about places where no data exists or concerning the future evolution of the Earth’s surface. Our section employs a range of researchers who all share a common interest in computer models, but who are from a variety of research backgrounds, including geology, geophysics and mathematics. We also work closely with colleagues in other sections of the GFZ as well as other German and international research institutions and universities.

Early Stage Researcher PhD position, Innovative Training Network “S2S-FUTURE”: modeling grain size distributions in rivers

Job Vacancy No. 3812

Research objectives

The sedimentary record contains invaluable information on past tectonic and climatic events. To decipher this information requires that we have an adequate understanding of how sediments are produced, transported and deposited. Recent work (Whittaker et al, 2011) has shown that the distribution of grain size in sedimentary deposits responds to variations in tectonic uplift and/or subsidence. However, no landscape evolution model exists that can efficiently predict the distribution of grain size in a sedimentary basin from known tectonic and climatic forcings. Davy and Lague (2009) have proposed a parameterization of sediment transport and how they affect river incision. Recently Yuan et al (2019) have developed an implementation of this parameterization in a 2D landscape evolution model that is highly efficient, i.e., implicit in time and of complexity O(n). However this model does not track grain size, nor the dependency of transport properties on grain size. In this project we propose to implement into a 2D landscape evolution model the self-similar model proposed by Fedele and Paola (2007) and incorporated in a simplified 1D model of a foreland basin by Duller et al (2010). Self-similarity assumes that the distribution of grain size remains relatively constant in shape and that transport/deposition processes act only to stretch and/or translate it, implying that knowledge of the evolution of mean grain size and standard deviation are sufficient to track grain size distribution through a given sedimentary system. The first objective of this project is to incorporate this self-similar model for grain size evolution into an existing landscape evolution model while keeping its high efficiency. The efficiency is essential because the model will then be used to reproduce observed grain size distributions from a sedimentary deposit that recorded the PETM event, using a Bayesian approach that requires a large number of model simulations be performed (i.e., of the order of hundreds of thousands of simulations). In this way constraints can be obtained on how the system has reacted to a major climatic event, as well as on poorly calibrated model parameters (such as the erosional rate constant or transport coefficient, and how they vary as a function of grain size). The second objective of this project is therefore to use the model to reproduce observed grain size distributions, validate the model and calibrate the model parameters and learn how sediment production and transport are affected by climate (change in temperature and rainfall).

Presentation of the research project (cooperative aspect)

This PhD position is within the framework of a European ITN project named S2S-FUTURE: SIGNAL PROPAGATION IN SOURCE TO SINK for the FUTUre of earth Resources and Energies involving 15 PhD positions. Under the supervision of Jean Braun (Professor, GFZ and University of Potsdam), the PhD student will develop a 2D numerical model of sediment transport that incorporate grain size tracking and will use observations from the Pyrenees. The project involves collaborations with multiple European institutions and industrial partners, including required research stays (secondment) at Imperial College London, England (Prof. Alex Whittaker; 2 months), University of Geneva, Switzerland (Prof. Sebastien Castelltort; 4 months, and Total, Pau, France (Dr. Charlotte Fillon; 1 month). The PhD student will be also involved in scientific/soft-skills meetings and in research activities conducted in other laboratories/companies from Europe and associated countries.
An important component of the training will be the participation to 3 main major “Summer Institutes”:
Summer 2020: “Dragonstone” – South-Pyrenees Spain and France: an innovative combination of field excursion and computer modeling of surface processes from source to sink.
Summer 2021: “The Factory” – Norway, Great Britain and Switzerland: field visit of modern S2S systems and course intensive program of technical and soft skills to accelerate the students’ research, write and present their results, consolidate their profiles and develop concrete plans for their future.
Summer 2022: “Inside Africa” – South-Africa: an immersion of ESRs in the modern source-to-sink system of a continental-scale large river, the Orange in Southern Africa, with high economic implications for mining industries.
In addition to these major milestones of the program, the PhD students will 1) continuously develop their core research skills via their own research project locally and within the network while at secondments and conferences, 2) receive a mandatory amount of hard and soft-skills training specific to their own doctoral school, along with mentoring by joint supervising bodies, 3) use EGU conferences both as dissemination events for ESRs results and network events for progress reports and evaluations, and 4) collaborate into practical activities aimed at network-structuring legacy deliverables.
The goal of S2S-FUTURE is to understand, quantify and model the sediment routing system from the sediment production (source) to the sediment deposition (sink); its tectonic and climatic controls; and to establish generic rules for a full understanding of signals propagation in S2S systems for building predictive models of sediment location and characteristics. These studies of S2S systems require interdisciplinary approaches combining geomorphology, sedimentology and stratigraphy, geochemistry, tectonic and paleoclimatology coupling observations, quantifications and process modelling. All these skills are integrated in the S2S-FUTURE project.
The objectives of S2S-FUTURE have been designed with primary societal implications in the domains of water, carbon-derived energy, sustainable geological energy and geological storage of non-geological energy, waste geological storage, mineral resources, and building materials. These points have become crucial for sustainable investment and development according to several of the United Nations Sustainable Development Goals such as SDG#6 (Clean water and sanitation), SDG#7 (Affordable and clean energy) and SDG#13 (Climate action) among others.


  • 3-years full-time employment contract
  • Attractive salary tuned to living standards of the hosting country.
  • Based in one of the top European institutions in Earth Sciences located in Potsdam and within commuting distance to Berlin.
  • Be part of a large and enthusiastic international team, where own initiatives and ideas are encouraged, with the opportunity to sculpting the future of Source-to-Sink research and network in Europe.
  • Possibility to collaborate with a large network of international research groups engaged in the ITN.


  • The candidate should be in the first four years of their research career. They should not have a doctoral degree and must fulfil the eligibility criteria and mobility rule (see below).
  • The candidate should hold or be about to obtain a Master’s degree in earth sciences, physics, engineering or applied mathematics.
  • Excellent technical skills including experience in numerical modeling and programming.
  • Training in the Earth sciences, preferentially sedimentology or geomorphology with demonstrated abilities (high marks) in applied mathematics.
  • Proficiency in written and spoken English.
  • The ability to work both as part of a team, and independently, coupled with excellent communication, organizational and problem-solving skills.
  • Availability to travel for training events and research secondments.

Eligibility criteria for this position:

Recruiting is in accordance with the European rules for Marie Curie Initial Training Networks. Early-stage researchers (ESR) can be of any nationality. They must be, at the time of recruitment by the host organization, in the first four years (full-time equivalent) of their research careers and have not yet been awarded a doctoral degree. The research career starts after the degree that enables a student to proceed with a PhD (usually, the Master degree).

Mobility rule:

At the time of the recruitment by the first host institution, the ESRs must not have resided or carried out their main activity (work, studies, etc.) in the country of their first host institution for more than 12 months in the 3 years immediately before the recruitment date. Short stays such as holidays and/or compulsory national service are not taken into account.
Starting date: 15th August 2020
Fixed term: 3 years
Salary: employee gross remuneration maximum 3560 euros per month if the conditions for family allowance are met (otherwise 500 euros less)
Working hours: full-time (currently 39 h/week); The position is, in principle, suitable for part-time employment.
Location: Potsdam
You can expect a very diverse and challenging job in an international work environment that is characterized by exciting research projects. The compatibility of work and family life is of particular concern to the GFZ. Therefore, it offers the opportunity for flexible working time and workplaces. Moreover, there is a kindergarten located on the research campus.
The GFZ is a partner with Geo.X (www.geo-x.net), and as such it is well connected with other geoscience institutions in Potsdam und Berlin. Geo.X forms the largest regional cluster of geoscientific expertise in Europe and offers excellent opportunities for cooperation and development.

How to apply

A single pdf file needs to be submitted including:
  • a cover letter, stating your research motivation and interests; including relevant background and career plan (max 1 A4 page)
  • a Curriculum Vitae, including academic background, previous research and/or industrial experience (max 2 A4 pages)
  • Degree transcripts (with marks)
  • English language qualification certificates (or equivalent)
Reference letters:
  • at least 2 confidential reference letters from academics (including name, position and email address of the referee) (max 1 A4 page, with substantiated assessment of the applicant’s technical skills, creativity, innovation ability, working capacity, efficiency and level of independence) must be sent directly to the contacts below.
Please submit your application online by 1st March 2020 using the “Apply” button.