March 2018
Message 53

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[Met-jobs] PhD position in cloud optical properties parameterization, Toulouse, France

From LIBOIS Quentin <>
Date Fri, 16 Mar 2018 10:44:32 +0100 (CET)

Dear colleagues,
Please find below (and attached) an offer for a PhD position at CNRM (Météo-France / CNRS) in Toulouse, France.
This deals with the parameterization of cloud/radiation interactions in numerical weather prediction models.
Don't hesitate to distribute to potential candidates.

Best regards

Quentin Libois

Evaluation and refinement of cloud optical properties parameterizations in the atmospheric model Meso-NH
PhD position at Centre National de Recherches Météorologiques (CNRM, Météo-France / CNRS)
Keywords: clouds, radiative transfer, numerical weather prediction, remote sensing

Location: CNRM, Toulouse, France
Application deadline: April 10th 2018
Duration: 3-year contract
Start: Fall 2018

Description of the position:
Radiative fluxes are a key component of climate dynamics. They drive surface fluxes, but also the energy budget of the bulk atmosphere, hence its dynamics. In numerical weather prediction models, these fluxes are computed according to the characteristics of the atmosphere : temperature and gas profiles, clouds and aerosols characteristics, etc. Cloud radiative effect is significant, but very complicated to simulate accurately. First because clouds geometrical structure is complex (3D radiative effects, unresolved spatial heterogeneities, cloud overlap), second because cloud-radiation interactions occur at microscopic scales. Indeed, cloud radiative effect fundamentally depends on cloud microphysical properties (droplets size distribution and number concentration, ice crystals shape), which are not always explicitly simulated in atmospheric models. In such case, cloud optical properties are parameterized. The parameterizations used in the atmospheric model Meso-NH have never been thoroughly evaluated, although the overall model is known to be sensitive to the choice of those parameterizations.

This thesis aims at evaluating the radiative performance of the model Meso-NH in cloudy conditions, and further improving the parameterizations of cloud optical properties. To this end, the simulated particle effective diameter and liquid water content will be individually evaluated, because both drive cloud optical properties. The parameterizations that convert these physical quantities into optical properties (optical depth, single scattering albedo, asymmetry parameter) will then be revised. The new parameterizations should be consistent with the convective and microphysical schemes as far as cloud type, meso-scale organization, and subgrid statistics are concerned. They will rely on the numerous theoretical and experimental studies published over the last 20 years, which include extensive satellite observations. The evaluation of radiative fluxes will be performed through the comparison of kilometric Meso-NH simulations to in situ and satellite radiation observations for a variety of cloud situations.

Required skills:
Candidates should meet the academic requirements to enter the Ph.D program. They should hold a Master degree, in atmospheric sciences or a related field.
Good skills in computing (Linux, Python, Fortran...), data handling and analysis would be appreciated. Previous research experience in cloud physics or radiative transfer would be an advantage.

Practical aspects:
CNRM is the research laboratory of Météo-France, the French weather service (
Applications will be considered as as soon as received.
The successful candidate will be involved in April in the application process for a national funding.

Application procedure:
Interested candidates should send the following documents by e-mail to Dr Quentin Libois (
- Curriculum Vitae;
- Application letter highlighting research interests and motivation for the position;
- The names and contact details of two referees (recommendation letters would be appreciated but are not compulsory);
- Master transcripts and name of the Master internship supervisor

For more details about the position, please see the attached document, and feel free to contact Dr Quentin Libois

----- Météo-France -----
Fixe : +33 561079691

Attachment: PhD_Thesis_CNRM_Cloud_Optical_Properties.pdf
Description: Adobe PDF document

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