Post-doctoral position in atmospheric processes

Centre National des Recherches Météorologiques (CNRM), Toulouse, France
Closing date: 15 April 2020

CNRM offers a post-doc position: Impact of mesoscale patterns on the boundary-layer processes and shallow clouds organisation within the trade wind: a modelling study

  • Required education: PhD in atmospheric science
  • From: as soon as 1 June 2020
  • Duration: 18 months
  • Salary: from 2300 to 2500 euros net/month depending on experience (CNRS salary grid)
  • Contact: Fleur couvreux (CNRM, fleur.couvreux@meteo.fr); Dominique Bouniol (CNRM, dominique.bouniol@meteo.fr)
  • Application: should include a CV,  statement of research activities and interests as well as the contact information for two referees
  • Application closure date: 15 April 2020

The « Centre National des Recherches Météorologiques » (CNRM) is a joined research center of Meteo-France, the French weather service, and CNRS. To carry out its missions, CNRM hosts approximately 275 permanent positions (one third being research scientists), and about 60 students and visitors. The CNRM is divided in 7 groups, among which the mesoscale meteorology group, GMME, leads studies (experimentally and numerically) on mesoscale and microscale processes of the atmosphere and its interfaces.
TROPICS, the host team part of GMME, has a specific expertise on atmospheric convective processes, including their numerical modelling with both Large Eddy simulations and mesoscale models and their observations with in particular satellite data. In the last decade, the team members have been involved in numerous studies on boundary-layer and convective processes. The team is also involved in the process-oriented evaluation of the AROME-OM, an operational forecast model run every day at 2.5km resolution over a large area of the Carribean.

Topic:
Boundary layer mechanisms leading to organization of shallow cumulus clouds investigated with Large-Eddy simulations and observations

Background:
CONSTRAIN (http://www.umr-cnrm.fr/constrain/) is a 4-year project funded by the European Union that started in May 2019. It aims at significantly improving our understanding of how natural and human factors affect multidecadal regional climate change in order to improve our capability to make climate projections for the next 20-50 years. It will rely on the combined analyses of CMIP6 runs with dedicated high resolution simulations and new observations to address identified knowledge gaps on radiative forcing, cloud feedbacks and the relationship between ocean variability and atmospheric change. One important objective is to make large use of observational data and in particular to take advantage of the dedicated field campaign on shallow cumulus, EUREC4A, that took place in January-February 2020 over Barbados (Bony et al. 2017). This field campaign provided observations of the low-cloud amount, of the lower vertical mixing of water vapour, and of the thermodynamic and dynamic environment in which the clouds form.

Work plan:
The main objective of the postdoc is to analyse the impact of mesoscale thermodynamical patterns on the boundary-layer processes and shallow clouds including their spatial organisation. To do so, the postdoc will mainly carry out different Large-Eddy simulations with Méso-NH (Lac et al 2018) focusing on two contrasted days where observations indicate different mesoscale organizations (probably Sugar and Flower type see Bony et al, 2020). A relatively large domain (~100km x 100km) inside the circle where most of aircraft observations were performed during the field campaign will be used. Sensitivity to different initial conditions starting from spatially homogeneous conditions towards more heterogeneous conditions provided either by observations (dropsondes from the HALO or variability inferred from satellites and different large-scale conditions derived either from the observations (large-scale velocity can be derived from frequent dropsondes launched on a circle , such a strategy was used during EUREC4A with a 90km radius circle) or from models at different resolutions (ECMWF analyses or AROME-OM, run operationally during the campaign at 2.5 and 1.3 km resolution)  will be studied. Additional sensitivities will be analysed such as the use of boundary conditions (cyclic or open boundary conditions with recycled turbulence as proposed by T Nagel, personal communication) as well as the influence of domain size.
All those simulations will be evaluated with respect to observations acquired during EUREC4A as well as satellite observations providing information on the mesoscale organization of clouds, humidity, temperature. In particular various metrics of organization (White et al 2018) will be applied to this set of simulations. Those LES will also serve as benchmark simulations to evaluate the operational mesoscale model AROME. Once evaluated, they will serve for understanding how the mesoscale patterns modify the boundary-layer processes and cloud spatial organisation and how small scale and meso scale  interacts with each other.

Practical aspects:
At Météo-France location, it is possible to get a room in a student residence for 160 € per month. Otherwise, access from the city centre is easy by Metro and Bus.

Salary will depend on the previous experience, and may evolve along the contract, in agreement with legal and employer regulations, with a lower limit of 2000 € net pay per month.

The post-doctoral contract will be a 18-month. It may start as soon as 1st June 2020, and preferably before 1st September 2020, but will remain open until the position is filled.

Qualifications:
To be eligible, the candidates should have a Ph.D. in the field of Atmospheric physics, with skills in meteorological modelling. Knowledge of atmospheric turbulence, convective parameterizations will be welcome. The successful candidate will have to run Large Eddy Simulations, in a Linux environment (with help from members of the team). He/she will be expected to attend international conferences and to publish his/her results in international peer-reviewed journals.

Applications:
Candidates should submit, before 15 April 2020, by email, a cover letter with a statement of research activities and interests, a CV, as well as the contact information for two referees to:

Fleur Couvreux, fleur.couvreux@meteo.fr
Dominique Bouniol, dominique.bouniol@meteo.fr

References:

  • Bony, S., B. Stevens, F. Ament, S. Bigorre, P. Chazette, S. Crewell, J. Delanoë, K. Emanuel, D. Farrell, C. Flamant, S. Gross, L. Hirsch, J. Karstensen, B. Mayer, L. Nuijens, J. H. Ruppert, I. Sandu, P. Siebesma, S. Speich, F. Szczap, J. Totems, R. Vogel, M. Wendisch, and M. Wirth. EUREC4A: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation. Surveys in Geophysics, 38:1529-1568
  • Bony S and B Stevens, 2019: Measuring Area-averaged vertical motions with dropsondes. J Atmos Sci, 76, 767-783
  • Bony, S., Schulz H, Vial, J, B. Stevens, 2020: Sugar, Gravel, Fish and Flowers:Dependence of Mesoscale Patterns of Trade-wind Clouds on Environmental Conditions, Geo. Res. Letters, In press.
  • Lac C et al. 2018: Overview of the Meso-NH model version 5.4 and its applications, GMD, 11, 5, 1929-1969, doi://10.5194/gmd-11-1929-2018
  • White B. A., Buchanan A. M., Birch C.E., Stier, P., Pearson K.J.: Quantifying the effects of horizontal grid length and parameterized convection on the degree of convective organization using a metric of the potential for convective interaction. J. Atmos. Sci, 2018, 75, 425-450

Share

By continuing to use the site, you agree to our privacy policy and the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close