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Bayi Glacier in Qilian Mountain, China (Credit: Xiaoming Wang, distributed via imaggeo.egu.eu)

Job advertisement Postdoctoral position in Atmospheric Modelling and Infrasound Propagation at CEA

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Postdoctoral position in Atmospheric Modelling and Infrasound Propagation at CEA

Position
Postdoctoral position in Atmospheric Modelling and Infrasound Propagation at CEA

Employer

CEA (French Alternative Energies and Atomic Energy Commission). Centre DAM Ile de France.


Location
Arpajon, France

Sector
Other

Relevant division
Atmospheric Sciences (AS)

Type
Contract

Level
Experienced

Salary
Salary commensurate with experience.

Required education
PhD

Application deadline
Open until the position is filled

Posted
1 October 2021

Job description

POSTDOCTORAL POSITION: Simulation of gravity waves in the middle atmosphere with the ICON
model: improving atmospheric specifications for infrasound propagation modeling

CONTEXT
In the last ten years it has become clear that the stratosphere and more generally the middle atmosphere
(MA) have important effects on tropospheric weather, as well as climate. To this respect it is critical to
assess the ability of numerical models to simulate MA dynamics and to improve their parameterizations
accordingly. Additionally, MA small scale disturbances like gravity waves (GW) have been identified as a
major impactor of detection capability of the International Monitoring System (IMS) infrasound network
of the Comprehensive Nuclear-Test-Ban Treaty (CTBT, http://www.ctbto.org) and their impact needs to
be quantified and better understood (Le Pichon et al. 2019). The ICOsahedral Non-hydrostatic (CON)
model, jointly developed by the Max Planck Institute for Meteorology and by the German Weather
Service (DWD), is a non-hydrostatic numerical weather prediction and research model that has recently
been extended to the upper-atmosphere (UA-ICON; Borchert et al. 2019) allowing to explicitly resolve a
large part of the GW spectrum at high resolution in the MA. Additionally, recent work undertaken by the
Goethe University Frankfurt (GUF) lead to the development of a GW parameterization (Bölöni et al.,
2021; Kim et al. 2021) that accounts for transient non-dissipative interactions between GW and the mean
flow, currently overlooked by more traditional parameterizations. ICON is thus a model of high interest to
assess atmospheric specifications by comparing infrasound observations to propagation simulations.
Through the use of long-term infrasound dataset available in the framework of the CTBT, one can access
unique constraints of the MA dynamics where observations are lacking. Previous work has already
demonstrated the benefit of combining infrasound with more traditional means of MA observation over
the course of the CEA-led European ARISE project (http://arise-project.eu/) (Blanc et al. 2018; Le Pichon
et al. 2015). One innovative way to assess models and calibrate their GW parameterization is by using
infrasound technology to perform propagation simulations and compare with infrasound observations.

OBJECTIVE
The work will consist in setting up and performing regional and global simulations with UA-ICON, using
the HPC infrastructure available at CEA, by choosing appropriate regions to focus on, based on existing
catalogues of infrasound observations from reference events (industrial explosions, volcanic eruptions…).
Simulation propagation tools will be used to confront the predicted arrival times and wave parameters to
observations at relevant regional and IMS infrasound stations. Errors will be quantified and related to the
model biases in the MA, based on the high-resolution observations available from ground-based
instruments from previous ARISE campaigns. The ability of the UA-ICON model to rely on the GW
parameterization at coarse resolution will be evaluated by comparing propagation simulations performed
with coarse (with parametrization) and high-resolution (without parametrization) atmospheric simulation
outputs. Comparisons with simulation propagations using analysis and reanalysis products will be
performed, in order to quantify the differences between models in the MA, and assess the ability of
infrasound observation to provide a diagnostic tool to evaluate models. Attempts to adjust the GW
parameterization developed by the Goethe University Frankfurt (Bölöni et al, 2021; Kim et al. 2021) for
the ICON model will be undertaken in order to assess the feasibility of relying on infrasound for model
improvements. Importantly, the impact of GW on the detection capability of the IMS and the global
morphology of infrasound propagation will be studied in order to help refine detection capability maps,
in the framework of the CTBT.

START DATE
January 2022 preferentially (position open until filled) – 24 months

QUALIFICATION
PhD in atmospheric science or related field, good skills in numerical modelling (required) and with HPC
environment (preferred), experience in atmospheric modelling (preferred), good knowledge of
Python/Matlab and Linux environment, interest in multidisciplinary research (atmosphere, acoustic), good
English language skills (writing and speaking).

REFERENCES
Blanc, E., Ceranna, L., Hauchecorne, A. et al. Toward an Improved Representation of Middle
Atmospheric Dynamics Thanks to the ARISE Project. Surv Geophys 39, 171–225 (2018).

Borchert, S., Zhou, G., Baldauf, M., Schmidt, H., Zängl, G., and Reinert, D. (2019): The upper-
atmosphere extension of the ICON general circulation model (version: ua-icon-1.0), Geosci. Model Dev.,
12, 3541–3569

Bölöni, G., Kim, Y., Borchert, S., & Achatz, U. (2021). Toward Transient Subgrid-Scale Gravity
Wave Representation in Atmospheric Models. Part I: Propagation Model Including Nondissipative Wave–
Mean-Flow Interactions, Journal of the Atmospheric Sciences, 78(4), 1317-1338

Kim, Y., Bölöni, G., Borchert, S., Chun, H., & Achatz, U. (2021). Toward Transient Subgrid-Scale
Gravity Wave Representation in Atmospheric Models. Part II: Wave Intermittency Simulated with
Convective Sources, Journal of the Atmospheric Sciences, 78(4), 1339-1357

Le Pichon, A., Ceranna, L., Vergoz, J., & Tailpied, D. (2019). Modeling the detection capability of
the global IMS infrasound network. In Infrasound Monitoring for Atmospheric Studies (pp. 593-604).
Springer, Cham.

Le Pichon, A., et al. (2015), Comparison of co-located independent ground-based middle
atmospheric wind and temperature measurements with numerical weather prediction models, J.
Geophys. Res. Atmos., 120, 8318–8331, doi:10.1002/2015JD023273.


How to apply

APPLICATION :
Please send CV and motivation letter, as well as at least two contact persons as potential referees.

CONTACT PERSON :
Constantino Listowski (constantino.listowski@cea.fr)
Phone number : +33 (0)1 69 26 40 00