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18-month post-doctoral position on "Multi-scale merging of satellite measurements of the water cycle" at the LSCE  

Please, find below the description of a 18-month postdoc position available at LSCE/IPSL (Gif-sur-Yvette, France).
Feel free to distribute it to your professional network and to any potentially interested colleague.

Best regards,
Mathieu Vrac




18-month post-doctoral position on "Multi-scale merging of satellite measurements of the water cycle"
Laboratory : LSCE
Place : Gif-sur-Yvette (France)
Employer : Université de Versailles Saint-Quentin
Dead-line for application : 28-02-2017
Start : As soon as possible from spring 2017

The “Laboratoire des Sciences du Climat et de l’Environnement” (LSCE-IPSL) and the “Laboratoire Atmosphère, Milieux, Observations Spatiales” (LATMOS-IPSL) are offering a 18-month post-doctoral position for the statistical modelling and merging of satellite measurements at various spatial and temporal scales. This position is part of the “SPACEOBS” IRS project supported by the Paris-Saclay University and will be based at the LSCE (Gif-sur-Yvette, France).


A part of the SPACEOBS project aims at constraining the tropical water cycle and assessing its role in the global climate and in the occurrence of tropical extreme events. This will be achieved by bringing together, for the first time, multivariate satellite observations of (i) the tropical water vapor and energy budgets provided by the sensors of the Megha-Tropiques mission, sampling the diurnal cycle owing to its unusual orbit, (ii) the detailed vertical distribution of cloud and precipitations provided by the series of instruments of the A-Train constellation, and (iii) the tropospheric wind profiles measured by the coming ADM-Aeolus mission. This will require scale studies between the various observing systems, with an innovative approach to merge the observational sets by dealing with the different space and time resolutions of clouds, precipitations, water vapor, radiation and dynamic, which are central elements of the climate sensitivity. This merging will be performed via the design of dedicated tropical upscaling/downscaling statistical approaches to build a robust synergy between the observations. This new ensemble of (merged) observations will be used to address other scientific questions in the SPACEOBS project, such as related to: the self-aggregation of convection (aka “iris effect”), or the impact of the El-Niño phenomenon on the occurrence of extreme events in the tropics.

Description of the post-doc work:

The post-doc fellow will analyse the space and time scale relationships between different observing systems over the tropics: A-Train constellation (CALIOP/Calipso: CPR/CloudSat; CERES/Aqua), Megha-Tropiques satellite (SAPHIR, ScaRaB) and the upcoming ADM-Aeolus. In particular, he/she will develop and compare statistical upscaling/downscaling models to generate the merged observational dataset. The work will specifically consist in:

  • Handling a first set of statistical downscaling methods  (e.g., GAM, Analogues, SWG) that will be tested on a representative sample of satellite measurements. Such well-known methods have never been used for data fusion before.
  • Quantifying the quality and robustness of the results based on geostatistical techniques for structural spatial analysis (e.g., variograms)
  • Selecting and developing the retained scaling method specifically designed to account for space/time characteristics of the satellite measurements
  • Analysing the results and understanding the uncertainties arising from the transfer to different spatial and temporal scales
  • Transferring the methodology for implementation in a general workflow
  • Collaborating on adjustments of the approach to meet the scientific needs of the other scientific questions within the project
  • Communicating the results through international conferences and at least one scientific article in a peer review journal.

Related teams:

  • Extremes – Statistics – Impacts – Regionalization ( ESTIMR at LSCE)
  • Statistique Processus Aérosols Cycle de l'Eau ( SPACE at LATMOS)
  • Dynamique et physique de l'atmosphère et des océans ( DPAO at LMD)
Required skills and background:

A PhD is required, preferably in remote sensing, atmospheric or climate sciences, with an experience in statistical analysis and statistical theory. Ease in using UNIX, shell scripting, and other programming languages (ideally R) is necessary, as well as being able to work in teams.

Salary : Net monthly salary around 2 000 euros, commensurate with experience. This includes social services and health insurance.
Contact :

Applications should be submitted by e-mail to Mathieu Vrac (, Hélène Brogniez ( and Hélène Chepfer ( as soon as possible and must include

  • a CV
  • a statement of research interests
  • the names of at least two references including e-mail addresses and telephone numbers.



Mathieu Vrac

Laboratoire des Sciences du Climat et de l'Environnement, (LSCE-IPSL)
Centre d'Etudes de Saclay, Orme des Merisiers, Bat. 701
91191 Gif-sur-Yvette, FRANCE

Email :
Phone : (+33)   Fax  : (+33)
Web :

StaRMIP project website:
A. Mazaud, dépêche du 05/01/2017
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