Two post-docs and one engineer in Earth System Modeling for Deep Time issues

General description of the project

Over the last decades, increasing acquirements of well-dated, high-resolution records from marine sediments and developments in carbon cycle models have raised much interest in understanding the role and impact of the organic carbon cycle on climate and on the biogeochemical state of the ocean. Its role in the regulation of atmospheric CO2 may for example have been substantial, in particular during severe events of marine anoxia in generally extremely warm climates such as the mid-Cretaceous. In the current context of extreme climate change, upheavals in the marine organic carbon cycle may therefore crucially affect our future, yet our knowledge of this carbon sink remains incomplete.

The biological pump indeed integrates processes affecting several compartments of the Earth System, such as continental alteration, ocean dynamics, ocean biochemistry but also sedimentary burial and marine ecology. As part of a large industry-supported project, we propose to use major intervals of organic matter burial in the Cretaceous as extreme and constrained benchmarks to improve our understanding of the marine biological pump and its representation in the IPSLCM5A2 Earth System model. Embedded in a comprehensive model-data comparison framework, the results will then be used to evaluate the organic carbon burial response to future, millennial-scale projections.

Model developments envisioned in this project will improve the representation of both continental weathering and fluxes of nutrient and detrital material to the ocean. Up-to-date representation of the sulfur cycle in the ocean and different representations of marine ecology will be implemented, and the coupling with the marine sedimentary system will also be explored.

Two postdoctoral positions and one engineer position of 3 years are offered as part of this project, with additional details below. We are looking for motivated, creative and dynamic candidates. A prerequisite will be a minimum of experience in numerical modeling, knowledge of the use of climate models (or other types of models) and a very strong ability to analyze model outputs. The work will be carried out mainly at CEREGE in Aix en Provence, a region benefiting from the exceptional climate of the Mediterranean. Collaborations with Y. Goddéris (GET, Toulouse), S. Arndt and P. Regnier (ULB, Brussels) and researchers from the IPSL (Paris) will provide the successful candidates with a strong network. These collaborations will involve frequent trips to these cities.

Please contact Yannick Donnadieu (donnadieu@cerege.fr)

Postdoctoral Scientist 1: Continental weathering and its coupling with ocean biogeochemistry during the Cretaceous

The successful candidate will be part of the Climate team at CEREGE, whose members perform and analyze Earth System model simulations covering various time slices across the Meso-Cenozoic with an interactively coupled atmosphere-ocean-vegetation-biogeochemistry model. The IPSL-CM5A2 model system consists of the LMDz atmospheric model, the NEMO model (including ORCA2, LIM3 and PISCES2), and the ORCHIDEE vegetation model. Climate simulations with CM5A2 for the Aptian, the Albian, the Cenomano-Turonian and the Maastrichtian are underway and will be available for the project. The first objective of this position is to use climatic outputs to constrain both chemical and physical continental fluxes reaching the ocean, namely the riverine suspended component, the nutrient inputs and potentially the continental organic matter.

Continental-scale weathering models have been developed by Yves Goddéris and colleagues at the GET in Toulouse with the overarching aim to account for both chemical and physical terms. An updated version of the Gabet and Mudd model (2009) has been coupled to the GEOCLIM model. The resulting numerical model considerably improves the calculation of the weathering fluxes, accounting for the mitigation of weathering by the development of the regolith on the continental surfaces. This coupling allows to calculate simultaneously the atmospheric CO2, the climate, the distribution of regolith, and the suspended and dissolved load delivered by the rivers to the oceans.

The candidate will investigate a whole range of parameters to define uncertainties on the flux's maps generated by the project. Two versions of the atmospheric model will be used to test the dependency of our results on both the spatial resolution and the physics of the system. Several parameters in the GET's model will also be investigated. The second objective of the project is to integrate these fluxes in both the biogeochemical component of IPSLCM5A2 (PISCES) and in the GEOCLIM model to test their respective roles on both the marine carbon cycle and the long-term carbon cycle.

Requirements:

  • The candidates must hold a PhD in the geosciences, including Paleoclimate, Biogeochemistry, Oceanography or a related science.
  • Experience in performing and analyzing experiments with a comprehensive earth system model or other numerical tools (sediment, weathering etc.);
  • The candidates should have the ability to work at other locations (weeks) including the GET in Toulouse and the IPSL in Paris.
  • Ability and desire to work in a closely cooperating team but also independently;
  • Excellent communication skills; very good writing proficiency in English;
  • Familiarity with coding and running computer models, very good programming skills in Fortran, Python or equivalent and scripting;
  • Demonstrable skills with relevance to biogeochemical or Earth system modelling are an asset.

Employment condition - The position is starting as soon as possible. Net salary will be between 2000 and 2750 euros (exact salary will depend on the experience). The contract is for three years with full French social security benefits (medical insurance, unemployment benefit, pension, maternity leave and child benefit) and with an evaluation after the first year.

Selection criteria - Candidates will be evaluated based on their qualifications and ability to fulfill the responsibilities as outlined for this project.

Deadline for applying

All applications received prior to June, 1st 2020, will be given full consideration. The search will be continued until the positions are filled.

We are looking forward to receiving your application

including the following documents:

  • A motivation letter stating research experiences and interests
  • A detailed curriculum vitae including a list of publications
  • The names, addresses, and telephone numbers of two referees

Postdoctoral Scientist 2: Interaction between the ocean dynamics and the sedimentary component to understand the onset and the spatial extent of Cretaceous OAEs

The successful candidate will be part of the Climate team at CEREGE, who performs and analyzes Earth System model simulations covering various time slices across the Meso-Cenozoic with an interactively coupled atmosphere-ocean-vegetation-biogeochemistry model. The IPSL-CM5A2 model system consists of the LMDz atmospheric model, the NEMO model (including ORCA2, LIM3 and PISCES2), and the ORCHIDEE vegetation model. Cretaceous climate simulations with CM5A2 for the Aptian, the Albian, the Cenomano-Turonian and the Maastrichtian stages are underway and will be available for the project. The first objective of this position is to work on the representation of the marine carbon cycle within the biogeochemical component of IPSLCM5A2 (PISCES) and to improve it by implementing the sulfur cycle in the water column. There is indeed evidence for vast area undergoing sulfato-reduction within the water column during the Cretaceous oceanic anoxic events. The second objective is to evaluate the ability of the model to produce spatial maps of organic matter accumulation on the sea-floor in agreement with IODP data. In this context, the sedimentary module of the PISCES model will be used and may be updated using recent developments done in Hulse et al. (GMD, 2018). Sensitivity to atmospheric CO2 levels and orbital parameters will allow assessing the response of the sedimentary system to the various environmental changes documented during the Aptian and the Cenomano-Turonian.

Requirements:

  • The candidates must hold a PhD in the geosciences, including Paleoclimate, Biogeochemistry, Oceanography or a related science.
  • Experience in performing and analyzing experiments with a comprehensive earth system model or other numerical tools (sediment, weathering etc.);
  • The candidates should have the ability to work at other locations (weeks) including the ULB in Brussels and the IPSL in Paris.
  • Ability and desire to work in a closely cooperating team but also independently;
  • Excellent communication skills; very good writing proficiency in English;
  • Familiarity with coding and running computer models, very good programming skills in Fortran, Python or equivalent and scripting;
  • Demonstrable skills with relevance to biogeochemical or Earth system modelling are an advantage.

Employment condition - The position is starting as soon as possible. Net salary will be between 2000 and 2750 euros (minimum amount, exact salary will depend on the experience). The contract is for three years with full French social security benefits (medical insurance, unemployment benefit, pension, maternity leave and child benefit) and with an evaluation after the first year.

Selection criteria - Candidates will be evaluated based on their qualifications and ability to fulfill the responsibilities as outlined for this project.

Deadline for applying

All applications received prior to June, 1st 2020, will be given full consideration. The search will be continued until the positions are filled.

We are looking forward to receiving your application

including the following documents:

  • A motivation letter stating research experiences and interests
  • A detailed curriculum vitae including a list of publications
  • The names, addresses, and telephone numbers of two referees

Engineer position

General context

The research activities of the Climate team (https://www.cerege.fr/en/research/climate-research-group) have evolved since 2017 through the emergence of actions on long time scales, coupling aspects of pre-Quaternary long-term modelling and paleoclimatic reconstructions. This evolution stems from the imperative need to understand the climate system under conditions very different from the current one. The growth of computing resources, from the local level via the meso-centre of the OSU PYTHEAS, to the national level via the TGIR (IRENE and JEAN ZAY supercomputers) opens up a methodological field in modelling in the scientific fields of the CEREGE Climate team in close relationship with laboratories at the IPSL (LSCE, LOCEAN and LMD). The combination of the emergence of these computational tools and of complex and massive datasets makes it possible to envisage a more frequent use of climate models in conditions different from those we currently experience, such as the colder conditions of glacial climates and/or the warmer conditions of older periods (Miocene, Eocene, Cretaceous). The coupling of data analysis with a modelling approach is generally fruitful and often leads to major discoveries. These activities have been developed in recent years with several ANR and ERC projects and strong support from industrial partners.

Description of potential activities (please note that we are aware that only one person cannot fill in all these duties - depending on the skills, the profile will be adapted and sharpened)

  • The engineer will be in charge of the development of software to configure the boundary conditions of climate simulations, to develop visualization tools to check the relevance of these boundary conditions and finally to analyze these climate model outputs. The successful candidate will be in charge of implementing this software and optimizing them for deployment on local, regional to national computer networks via computing centers.
  • The engineer will be in charge of developing optimization and interfacing tools for coupling between different model compartments: Earth System models indeed imply many couplings between pre-existing models (i.e. atmosphere - ocean - sea ice - marine biogeochemistry - ecology etc.) that do not have the same numerical grids.
  • The engineer will assist and help the two postdocs hired within this project to implement their own development in the IPSL model and in the GEOCLIM model and will work closely support computing teams at the IPSL.

Requirements:

  • The candidate should hold or be about to obtain a Master's degree or Engineer's degree in Earth sciences, physics or applied mathematics;
  • The candidates should have the ability to work at other locations (weeks) including the IPSL in Paris, the GET in Toulouse and the ULB in Brussels;
  • Ability and desire to work in a closely cooperating team but also independently;
  • Excellent communication skills;
  • Excellent skills in coding and running computer models, very good programming skills in Fortran, Python, Java or equivalent and scripting.

Employment condition - The position is starting as soon as possible. Net salary will be around 1800 euros (minimum amount, exact salary will depend on the experience). The contract is for three years with full French social security benefits (medical insurance, unemployment benefit, pension, maternity leave and child benefit) and with an evaluation after the first year.

Selection criteria - Candidates will be evaluated based on their qualifications and ability to fulfill the responsibilities as outlined for this project.

Deadline for applying

All applications received prior to June, 1st 2020, will be given full consideration. The search will be continued until the positions are filled.

We are looking forward to receiving your application

including the following documents:

  • A motivation letter stating your motivations and interests
  • A detailed curriculum vitae including academic background
  • The names, addresses, and telephone numbers of two referees from two academics or other if applicable

posted: 09 March 2020 Please mention EARTHWORKS when responding to this advertisement.