Laboratoire Interuniversitaire des Systèmes Atmosphériques
Présentation
Le LISA, Laboratoire Interuniversitaire des Systèmes Atmosphériques est une unité de recherche de structure originale dépendant des Universités Paris Est Créteil et Paris Diderot, et du CNRS (UMR CNRS 7583).
Le LISA compte environ 130 personnes, dont 50 enseignants-chercheurs et chercheurs (CNRS & IRD), 36 ITA-IATOS et environ 45 post-doctorants, doctorants et étudiants de Master.
Il dispose d'un important potentiel technique et expérimental réparti sur 3.600m2 de locaux à Créteil et d'une antenne opérationnelle sur le site Paris Rive Gauche, incluant aussi des équipements lourds. Les recherches y sont développées autour d’un thème générale : l’Atmosphère (comme le nom du laboratoire l’indique), Ses principaux thèmes de recherche portent ainsi sur la compréhension du fonctionnement des atmosphères terrestres et planétaires, et des impacts liés à la modification de la composition de l'atmosphère par les activités humaines. Les méthodes utilisées sont fondées sur des observations en atmosphère réelle, sur de la simulation expérimentale en laboratoire et de la modélisation numérique.
Pour mener à bien ces recherches, le LISA regroupe des scientifiques de plusieurs disciplines : physiciens, géochimistes, environnementalistes et une majorité de chimistes. Ce dernier aspect est une de ses caractéristiques importantes par rapport aux autres laboratoires du domaine. Un département technique (doté de 4 pôles : chimie, instrumentation, terrain et informatique) et un département administratif sont en soutien des activités de recherche.
Thèmes de recherche
- Pollution atmosphérique Oxydante et Particulaire
- Devenir du Carbone Organique
- Cycle de l’Aérosol Désertique
- Spectroscopie et Atmosphères
- Exobiologie et Astrochimie
[hal-01587498] Impacts of regional climate change on air quality projections and associated uncertainties
Date: 14 sep 2017 - 12:56
Desc: [...]
[hal-02328263] Non-steady state biological removal of atmospheric particles from Mediterranean surface waters
Date: 24 oct 2019 - 16:03
Desc: [...]
[insu-01182128] Comet 67P/Churyumov-Gerasimenko sheds dust coat accumulated over the past four years
Date: 30 juil 2015 - 15:48
Desc: Comets are composed of dust and frozen gases. The ices are mixed with the refractory material either as an icy conglomerate1, or as an aggregate of pre-solar grains (grains that existed prior to the formation of the Solar System), mantled by an ice layer2, 3. The presence of water-ice grains in periodic comets is now well established4, 5, 6. Modelling of infrared spectra obtained about ten kilometres from the nucleus of comet Hartley 2 suggests that larger dust particles are being physically decoupled from fine-grained water-ice particles that may be aggregates7, which supports the icy-conglomerate model. It is known that comets build up crusts of dust that are subsequently shed as they approach perihelion8, 9, 10. Micrometre-sized interplanetary dust particles collected in the Earth’s stratosphere and certain micrometeorites are assumed to be of cometary origin11, 12, 13. Here we report that grains collected from the Jupiter-family comet 67P/Churyumov-Gerasimenko come from a dusty crust that quenches the material outflow activity at the comet surface14. The larger grains (exceeding 50 micrometres across) are fluffy (with porosity over 50 per cent), and many shattered when collected on the target plate, suggesting that they are agglomerates of entities in the size range of interplanetary dust particles. Their surfaces are generally rich in sodium, which explains the high sodium abundance in cometary meteoroids15. The particles collected to date therefore probably represent parent material of interplanetary dust particles. This argues against comet dust being composed of a silicate core mantled by organic refractory material and then by a mixture of water-dominated ices2, 3. At its previous recurrence (orbital period 6.5 years), the comet’s dust production doubled when it was between 2.7 and 2.5 astronomical units from the Sun14, indicating that this was when the nucleus shed its mantle. Once the mantle is shed, unprocessed material starts to supply the developing coma, radically changing its dust component, which then also contains icy grains, as detected during encounters with other comets closer to the Sun4, 5.
[hal-01631937] Astrochemistry: Complex organic matter in Titan's aerosols? (Reply)
Date: 9 nov 2017 - 17:57
Desc: Biemann et al. calls into question our preliminary interpretations of our experimental results. A comparison of laboratory and flight measurements should settle the uncertainties he raises. In addition to evaluating instrumental characteristics such as the 'piston effect', a technique we used for injecting oven-gas content for gas chromatography-mass spectrometry (GC-MS), such studies should enable a wide range of possible compositions for Titan's aerosols to be investigated. Our aerosol collection and pyrolysis (ACP) measurements in Titan's atmosphere can then be revisited.
[hal-00081646] Complex organic matter in Titan's atmospheric aerosols from in situ pyrolysis and analysis
Date: 23 juin 2006 - 17:42
Desc: Aerosols in Titan's atmosphere play an important role in determining its thermal structure1, 2, 3. They also serve as sinks for organic vapours4 and can act as condensation nuclei for the formation of clouds5, 6, where the condensation efficiency will depend on the chemical composition of the aerosols5, 7. So far, however, no direct information has been available on the chemical composition of these particles. Here we report an in situ chemical analysis of Titan's aerosols by pyrolysis at 600 °C. Ammonia (NH3) and hydrogen cyanide (HCN) have been identified as the main pyrolysis products. This clearly shows that the aerosol particles include a solid organic refractory core. NH3 and HCN are gaseous chemical fingerprints of the complex organics that constitute this core, and their presence demonstrates that carbon and nitrogen are in the aerosols. Top of page
Autres contacts
Direction du LISA
Maison des Sciences de l’Environnement 4ème étage
UPEC Campus Centre
61, avenue du Général de Gaulle
94010 CRETEIL CEDEX
contact@lisa.u-pec.fr / 01.45.17.15.60