South-West Regional Spatial Observatory

South-West Regional Spatial Observatory

Scientific context

The South-West Regional Spatial Observatory (OSR Sud-Ouest) was set up in 2002 in an agricultural area of 2500 km² located to the South-West of Toulouse, wich had  an exceptional coverage of medium and high resolution space images. Over time, observations have been extended to the Pyrenees and, since 2020 benefiting from the arrival of Sentinel images, four areas are more particularly monitored: the upstream Adour/Gave de Pau basin, the rivers of the Coteaux de Gascogne which depend on the Neste system, the alluvial valley of the Garonne and Ariège rivers and the Pyrenees chain. The geology is of the marl-limestone type and the climate is oceanic in the plain with Mediterranean influences during the summer and mountainous in the Pyrenees. Three stations are instrumented with continuous measurments Auradé, Lamasquère, Bernadouze and the acquired data are exploited for the calibration/validation (CAL/VAL) of products from remote sensing and surface process models. The research conducted in the South-West OSR also allow to develop and test strategic tools, operational services, algorithms, new sapce missions and field instrumentaion. The work is carried out in partnership with managers, decision-makers, and industrialists.

Summary

Starting year: 2002

Localisations : Pyrenees, Garonne, Ariège

Keywords: continental surfaces, climate change, landscape study, greenhouse gases

Database: https://osr.cesbio.cnrs.fr/acces-donnees/

Web site: https://osr.cesbio.cnrs.fr/

PI: Tiphaine Tallec 

Scientific questions

By combining satellite imagery, in situ data and modelling the scientific objectives of the South-West OSR are to understand, model and predict the functioning and evolution in the state of predominantly agricultural areas at the ecosystem, landscape, watershed and regional scales. It also aims to provide scientific bases for the strategic management of territories subject to global changes ( Il s’agit aussi d’apporter les bases scientifiques pour la gestion stratégique des territoires soumis à des changements globaux (climatic, anthropic). OSR allows:

  • The monitoring of changes and the impact of climate anomalies;
  • The development and validation of surface process models: energy, water, carbon, greenhouse gases, vegetation;
  • The regionalization of fluxes and balances by assimilation of spatial observations in the models;
  • The development of treatment algorithms and the creation of spatialized products.

Sites and measured variables

The Auradé (FR-Aur) and Lamasquère (FR-Lam) sites are agricultural plots located a few kilometers southwest of Toulouse. FR-Aur follows a winter wheat/sunflower/rapeseed rotation and benefits from a mineral nitrogen fertilization. FR-Lam follows a winter wheat/corn/winter wheat/corn/ rotation and benefits from mineral and organic nitrogen fertilization (d’une fertilisation azotée minérale et organique (livestock effluent like manure or slurry). The plot is irragated with an average of 120 mm of water per year. Both sites are part of the ICOS network – Integrated Carbon Observation System. They are equipped for continuous and high frequency measurment of meteorological data, radiation, CO2, NO2, water vapor and energy fluxes and some soil varaibles (temperature profiles, humidity…) Vegetation and soil are monitored in detail by numerous instruments. Surveys on mand use are also carried out every year as well as one-time campaign of intensive measurements at the scale of a territory (soil moisture, biomass, roughness, etc.) for the acquisation of reference data needed for CAL/VAL activities. 

The Bernadouze site aims to study the snow cover and the hydrological cycle in relation to land use changes a quant à lui pour objectif l’étude du manteau neigeux et du cycle hydrologique en lien avec les changements d’occupation des sols (afforestation/déforestation). It has a hydrometeorological and snow height monitoring.

Partners and further information

The OSR is managed by the CESBIO (Centre d’études spatiales de la biosphère) based in Toulouse. It is labeled  Service national d’observations (SNO) by the INSU/CNRS since 2007. The Bernadouze site is included in the Observatoire Homme Milieu Pyrénées Haut-Vicdessos and is monitored in collaboration with the GEODES and the Laboratoire Écologie Fonctionnelle et Environnement.

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