LATEX page


(LAgrangian Transport EXperiment)

Pilot project 2007 – Main project 2008 to 2011

PIs: Frédéric Diaz and Anne Petrenko (LOPB - COM)




Objective: influence of submesoscale coupled physics – biogeochemistry on cross-shelf (coast-offshore) exchanges

Methodology : lagrangian strategy to follow a submesoscale eddy using lagrangian floats and an inert chemical tracer (SF6)

Multi-disciplinary project + multi-«tools» (lagrangian floats, SF6, hull-mounted ADCP, moorings, satellite images, modelling, gliders, radars) for the 2010 September cruise

Site of study: Gulf of Lion, north-western Mediterranean sea

Anticyclonic eddy A1 (here on August 1st, 2001) detected with WATERS


* List of LATEX participants and connected projects.

* To learn more on the project, here is the scientific proposition (PDF) submitted to LEFE for 2008-2011

* And here is one of the latest oral presentation (PDF) of the project including some of the latest results (numerical and experimental); from my presentation at the Workshop Twisted (PI M/ Levy) in Paris, September 2008.

!!! What's New !!!  
* April 20-24, 2009 : Ziyuan Hu's poster (PDF) at EGU Vienna
* March 23-26, 2009 : Visit of Francesco Nencioli (UCSB) + seminar
* February 26-27, 2009 : Visit of Francesco d'Ovidio (LOCEAN) + seminar
* February 9-11, 2009 :

Visit of Anna-Lisa Griffa (La Spezia, RSMAS) + seminar - Postponed to later in the year because of the strike against the LRU and other governmental measures - check explanations on the LOPB web site

* February 3, 2009 : Paper Hu et al., Ocean Modelling, accepted :)
* Jan. 25-29, 2009 : Rose Campbell 's poster (PDF) at ASLO Nice
* November 2008 : Paper Hu et al., Ocean Modelling, in revision
* October 2008 :

Rose Campbell is starting her PhD on the biogeochemical modeling of the LATEX project (coupled with the physical modelling thesis of Ziyuan Hu) - CIFRE fellowship with ACRI; directors (Dr Dekeyser, Dr. Diaz)

* July 2008 : LATEX cruise on the RV Suroît planned for September 2010 - the cruise will take place aboard two RVs: the Suroît and the Téthys II
* January 2008 : LATEX project ranked A+ by LEFE
* June, 2007 : Following her Master II traineeship, Ziyuan Hu has started her PhD with us (Dr. Dekeyser, Dr Doglioli and I) on LATEX in September 2007

Tools used:

* WATERS Wavelet Analysis for Time-tracking Eddies

Wavelet analysis performed on relative vorticity calculated from Symphonie POC modelled currents

Other uses of WATERS can be found on Dr Doglioli 's webpage.

* ARIANE is a computational tool (Fortran 90/95) that is dedicated to the offline calculation of 3D streamlines in the output velocity field of an Ocean General Circulation Model (OGCM) such as OPA-NEMO, ROMS, Symphonie and any ocean model whose equations are based on volume conservation.

see ARIANE 's webpage realized by Nicolas Grima at LPO for more information.

LATEX00 Results


Click image to enlarge
Anticyclonic eddy A1 on August 1st; A1 was detected for 32 days from July 17, to August 18, 2001.
The WATERS package was used in order to track the eddy or filament structures of the Gulf of Lion. It was applied to horizontal maps of relative vorticity, calculated from the velocity outputs of the SYMPHONIE model (data provided by C.Estournel and P.Marsaleix, POC, Toulouse).
The ARIANE toolkit has been coupled with de SYMPHONIE model and has provided both qualitative and quantitative numerical trajectories.
Click image to enlarge
Ariane qualitative test: 170 lagrangian buoys were released in A1 on August 11, 2001 and followed for 51 days as shown in the three figures above (left to right) from day 6 to day 21, day 21 to day 36 and day 36 to day 51 (data provided by N.Grima, LPO, Brest).

@ Sea!

Tests of Lagrangian survey and determination of the background natural SF6 concentration.
Click image to enlarge
LATEX00 cruise (june 2007): real trajectories and trajectories in a Lagrangian referential centered on the buoy (top: test for the egyptian spiral, bottom: test for the radiator).
Click image to enlarge
Temperature and SF6 profiles at MOLA station (42.52°N, 3.54°E) on May 25, 2007.