[Statlist] PhD Position offers

[Olivier de Viron]

Hello,
Could you please send the following message to the stat list?
Thanks a lot,
odv
------------------------------------------------------
We propose a PhD thesis grant in geodesy (Earth Sciences), which will 
study what geostatistics
can bring to geodesy.

Geodesy is the part of Earth sciences which study the shape of the 
Earth, the gravity
potential, and the orientation of Earth in space, together with the 
space and time fluctuations of those quantities.
Geodesy is a powerful tool for geoscience studies, due to its accuracy 
and stability. Up to now, geostatistics
methods where not much used in the geodetic studies, and there were only 
a few studies using those tools on
the networks of GPS stations, for example. To further improve both 
accuracy and stability, and to go deeper in the understanding of the 
geophysical processes associated with the flucutations of the geodetic 
observables, it is required to include the impact of climate phenomena 
in the system, which is not an easy thing as the climate models do not 
have the required precision, partly because they are not build to 
satisfy the geodetic requirement, such as the mass conservation. 
Applying spatial correlation studies on geodetic data, we can get 
information and separate the climate impact on geodetic data, as they 
are characterized by reagional scale correlation, from more local 
phenomenon, which would includes discontinuities in the time series 
related to station issues for example. Geostatistic method also allow to 
filter out some signal based on their auto/cross-correlation. Those 
methods can thus also be seen as a source separation method, which a 
very important issue presently in geodesy. We plan to apply those 
methods to several datasets, separately and jointly. (1) Our lab is in 
charge of an international sea level observation service (SONEL), which 
would be our first dataset, in order to inverstigate how this can help 
in separating the climate related phenomena from other sources. (2) 
Preliminary studies tend to indicate that it would be possible to use 
auto-corrlation based filtering to correct for the striping noise in 
GRACE associated with the tidal phenomena. (3) A first set of tests 
indicate that variogram studies is an excellent detector of 
discontinuities in GPS time series; we plan to use that method to 
several local and regional solutions, in order to dertermine its jump 
detection efficiency; up to now, jump detection is mostly developed for 
mon-station time series.


The laboratory is located in La Rochelle. The laboratory brings together 
scientists from different research fields (earth sciences, biology, 
ecology, history, geography and
biochemistry) to study a common object: the coastal areas.


For more information:
Olivier de viron
+ 33 5 46 50 76 34
olivier.de_viron at univ-lr.fr <mailto:olivier.de_viron at univ-lr.fr>
LIttoral ENvironnement et Sociétés (LIENSs)
*Université de La Rochelle*
Bâtiment ILE
2, rue Olympe de Gouges
17000 La Rochelle
lienss.univ-larochelle.fr <http://lienss.univ-larochelle.fr>
www.univ-larochelle.fr <https://www.univ-larochelle.fr>
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