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Laboratoire d’Etudes en Géophysique et Océanographie Spatiales

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by LEGOS last modified Dec 18, 2016 11:11 PM

The development of precise orbital positioning systems in the 1970s and 80s, together with the advent of satellite altimetry with the launch of Topex/Poseidon in 1992, has created the new scientific discipline of high precision spatial oceanography. Subsequent research efforts in this field led in 2001 to the development of operational oceanography over the major ocean basins. This achievement flows from the synergy between fundamental research, technology and societal demand, and close cooperation in Toulouse between CNES et le GRGS, and more recently LEGOS and SC-MERCATOR Ocean.

This scientific evolution now continues at LEGOS in the new domains of earth system science, coastal oceanography, tropical dynamics, marine biogeochemistry, spatial hydrology, and cryospheric dynamics. Research groups investigating these themes pursue a multi-disciplinary approach, using in-situ observations, satellite measurements, modelling and data assimilation. LEGOS engages in these activities as part of the Observatoire Midi-Pyrénées and the University of Toulouse, , in close collaboration with locally based businesses such as (comme CLS and NOVELTIS),the national research organisations CNRS and IRD, and European and international programs.



LEGOS (UMR 5566) is a "mixed laboratory" comprising personnel from four employing organisations: Centre National d'Etudes Spatiales(CNES), the national research organisations(CNRS, Département des Sciences de l'Univers), the Institut de Recherche pour la Developpement (IRD) and the University Paul Sabatier (UPS). It is one of seven laboratories in the "Observatoire Midi Pyrenees" (OMP).LEGOS has about 100 members: 40 researchers, 20 technicians and 30 postgraduate students and postdoctoral and contract staff. LEGOS is also houses the French Navy hydrographic and oceanographic service(CMO-Toulouse). .


LEGOS is a multi-disciplinary research organisation , concerned with environmental research centred on physical oceanography (large scale and coastal), marine geochemistry and biogeochemistry, spatial hydrology and the dynamics of polar ice sheets. These research themes are linked by an observational approach using remote sensing from satellites. LEGOS is involved in all aspects of satellite missions, especially for altimetric satellites, from the planning and the preparation of algorithms to calibration, validation and exploitation of the results. LEGOS also maintains five observational services and networks.

LEGOS contributes actively to student formation , and is involved in university teaching and supervision at all levels from degree to masters and PhD studies through the university faculties of physical science (UFR PCA) and life and earth sciences (UFR SVT). LEGOS is particularly closely involved in masters courses in atmosphere, ocean and environmental science within the doctoral school SDU2E (Sciences de l'Univers, Espace et Environement).

Observational services and networks

LEGOS coordinates five observational services and networks:

- CTOH (Centre for the Topography of Oceans and the Hydrosphere), dedicated to satellite altimetry over the oceans and the continents. Growth areas for this activity are the coastal zones, continental hydrology and the cryosphere.

-DORIS, a data treatment centre for precise orbital positioning (in cooperation with the International Earth Reference System).

- ROSAME, an observational network for monitoring sea level which was initiated in the southern ocean with the support of IPEV and has been extended to tropical and European regions in cooperation with IRD and CNES.

- The SSS network for monitoring Sea Surface Salinity by merchant ships, which links five observational networks in the Pacific, Atlantic, Indian and Austral ocean basins.

- The moored buoy network PIRATA in the equatorial Atlantic, used for monitoring meteorological and oceanographic conditions between the surface and a depth of 500m. These data are complemented by oceanographic measuring campaigns that take place alongside routine maintenance of the buoys.

Scientific Activities

The scientific activities at LEGOS are grouped into four themes:

Research in glaciology incorporates detection and understanding of physical mechanisms of ice sheets and and their role in the climate system. The objectives are to improve modelling of ice flow, and to study the mass balance and the role of ice sheets in sea level change. A special area of interest is the relationship between antarctic variability and the southern hemisphere climate. The main observational technique used is satellite remote sensing (altimetry and radar interferometry).

Research in hydrology and satellite-based geodesy concerns: 1) Sea level variations: their observation and the study of their causes and impacts. 2) Global hydrology by satellite observation. The former is based on analysis from the Topex/Poseidon, Jason-1 and Envisat satellites. The latter consistes of an emerging community activity in continental hydrology, using a range of new altimetric and gravimentric data from the GRACE and GOCE satellites.

Research in physical oceanography covers a wide range of spatial and temporal scales from gravity waves (tides, response to storms) to seasonal and interannual variations of the global ocean. The relationship between these phenomena and climate is investigated in collaboration with operational oceanographers (MERCATOR). A number of projects are ongoing, concerning assimilation of heterogeneous data, analysis and evaluation of numerical simulations, mechanisms of interannual to decadal variability (particularly in the tropics), the formation and variability of water masses in the southern ocean and finally the development of coastal oceanography in the framework of the "Pole d'Oceanographie Cotiere" (POC) of the OMP, and the provincial office of CMO and SHOM.

Research in marine biogeochemistry is focussed in two distinct areas:

a- The study of chemical and isotopic tracers: the objective is to quantify the processes that determine the transfer of materials in the ocean and to reconstruct water mass trajectories and formation rates. Members of this group regularly take part in oceanographic observation campaigns as part of national and international programs. Analysis equipment (spectrometer, ICP/MS) is shared with the geochemistry group at LMTG (Laboratory for Mechanisms and Transfers in Geology - OMP).

b- Interactions between dynamics and primary production: the links between anthropogenic climate change and changes in ecosystems and marine biogeochemical cycles can be characterised as responses, impacts and feedbacks. Two complementary themes are pursued in this group: : i) at the regional scale, the changes in structure and functioning of marine ecosystems (pelagic and coastal zones) in response to climate change from seasonal to decadal timescales; ii) the future form of in-situ monitoring of biogeochemical processes in the ocean.

> Click here for more information about research at LEGOS

LEGOS has five centres of activity:

- The main site in Toulouse brings together all the themes of the laboratory, as detailed in the drop-down menus above.

- The LEGOS site in Noumea, New Caledonia, is dedicated to studying the equatorial Pacific and western tropics, and regional environmental studies. It is located in the Noumea IRD centre, and cooperates closely with IRD's "IMAGO" service.

- In Peru, researchers and students from LEGOS work in cooperation with the Institut del Mar del Peru (IMARPE, Lima).

-In Brazil, LEGOS cooperates with ANA in Brasilia for hydrological studies of the Amazon basin, using satellite techniques in cooperation with LMTG.

- In Benin, LEGOS collaborates with the Centre des Recherches Halieutiques et Oceanographiques du Benin a Cotonou (CHROB) on regional programs, and participates in an international masters course entitled "Physical Oceanography and applications", which brings together students from the countries of the region at the University of Abomey Calavi in Cotonou.


Mise à jour 25/05/2009


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