Laboratoire Interuniversitaire des Systèmes Atmosphériques
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-04115869] The ash dispersion over Europe during the Eyjafjallajökull eruption - Comparison of CMAQ simulations to remote sensing and air-borne in-situ observations
Date: 2 juin 2023 - 17:47
Desc: The dispersion of volcanic ash over Europe after the outbreak of the Eyjafjallajökull on Iceland on 14 April 2010 has been simulated with a conventional three-dimensional Eulerian chemistry transport model system, the Community Multiscale Air Quality (CMAQ) model. Four different emission scenarios representing the lower and upper bounds of the emission height and intensity were considered. The atmospheric ash concentrations turned out to be highly variable in time and space. The model results were compared to three different kinds of observations: Aeronet aerosol optical depth (AOD) measurements, Earlinet aerosol extinction profiles and in-situ observations of the ash concentration by means of optical particle counters aboard the DLR Falcon aircraft. The model was able to reproduce observed AOD values and atmospheric ash concentrations. Best agreement was achieved for lower emission heights and a fraction of 2% transportable ash in the total volcanic emissions. The complex vertical structure of the volcanic ash layers in the free troposphere could not be simulated. Compared to the observations, the model tends to show vertically more extended, homogeneous aerosol layers. This is caused by a poor vertical resolution of the model at higher altitudes and a lack of information about the vertical distribution of the volcanic emissions. Only a combination of quickly available observations of the volcanic ash cloud and atmospheric transport models can give a comprehensive picture of ash concentrations in the atmosphere.
[hal-01139588] Impact of dust deposition on carbon budget: a tentative assessment from a mesocosm approach
Date: 9 déc 2015 - 15:32
Desc: By bringing new nutrients and particles to the surface ocean, atmospheric deposition impacts biogeochemical cycles. The extent to which those changes are modifying the carbon balance in oligotrophic environments such as the Mediterranean Sea that receives important Saharan dust fluxes is unknown. The DUNE (DUst experiment in a low Nutrient, low chlorophyll Ecosystem) project provides the first attempt to evaluate the changes induced in the carbon budget of a large body of oligotrophic waters after simulated Saharan dust wet or dry deposition events, allowing us to measure (1) the metabolic fluxes while the particles are sinking and (2) the particulate organic carbon export. Here we report the results for the three distinct artificial dust seeding experiments simulating wet or dry atmospheric deposition onto large mesocosms (52 m<sup>3</sup>) that were conducted in the oligotrophic waters of the Mediterranean Sea in the summers of 2008 and 2010. Although heterotrophic bacteria were found to be the key players in the response to dust deposition, net primary production increased about twice in case of simulated wet deposition (that includes anthropogenic nitrogen). The dust deposition did not produce a shift in the metabolic balance as the tested waters remained net heterotrophic (i.e., net primary production to bacteria respiration ratio <1) and in some cases the net heterotrophy was even enhanced by the dust deposition. The change induced by the dust addition on the total organic carbon pool inside the mesocosm over the 7 days of the experiments, was a carbon loss dominated by bacteria respiration that was at least 5–10 times higher than any other term involved in the budget. This loss of organic carbon from the system in all the experiments was particularly marked after the simulation of wet deposition. Changes in biomass were mostly due to an increase in phytoplankton biomass but when considering the whole particulate organic carbon pool it was dominated by the organic carbon aggregated to the lithogenic particles still in suspension in the mesocosm at the end of the experiment. Assuming that the budget is balanced, the dissolved organic carbon (DOC) pool was estimated by the difference between the total organic carbon and the particulate organic carbon (POC) pool. The partitioning between dissolved and particulate organic carbon was dominated by the dissolved pool with a DOC consumption over 7 days of ∼1 μmol C L<sup>-1</sup> d<sup>-1</sup> (dry deposition) to ∼2–5 μmol C L<sup>-1</sup> d<sup>-1</sup> (wet deposition). This consumption in the absence of any allochthonous inputs in the closed mesocosms meant a small <10% decrease of the initial DOC stock after a dry deposition but a ∼30–40% decrease of the initial DOC stock after wet deposition. After wet deposition, the tested waters, although dominated by heterotrophy, were still maintaining a net export (corrected from controls) of particulate organic carbon (0.5 g in 7 days) even in the absence of allochthonous carbon inputs. This tentative assessment of the changes in carbon budget induced by a strong dust deposition indicates that wet deposition by bringing new nutrients has higher impact than dry deposition in oligotrophic environments. In the western Mediterranean Sea, the mineral dust deposition is dominated by wet deposition and one perspective of this work is to extrapolate our numbers to time series of deposition during similar oligotrophic conditions to evaluate the overall impact on the carbon budget at the event and seasonal scale in the surface waters of the northwestern Mediterranean Sea. These estimated carbon budgets are also highlighting the key processes (i.e., bacterial respiration) that need to be considered for an integration of atmospheric deposition in marine biogeochemical modeling.
[hal-01120866] Orbitrap-based mass analyser for in-situ characterization of asteroids: ILMA, Ion Laser Mass Analyser
Date: 26 fév 2015 - 17:17
Desc: Since about a decade the boundaries between comets and carbonaceous asteroids are fading [1,2]. No doubt that the Rosetta mission should bring a new wealth of data on the composition of comets. But as promising as it may look, the mass resolving power of the mass spectrometers onboard (so far the best on a space mission) will only be able to partially account for the diversity of chemical structures present. ILMA (Ion-Laser Mass Analyser) is a new generation high mass resolution LDI-MS (Laser Desorption-Ionization Mass Spectrometer) instrument concept using the Orbitrap technique, which has been developed in the frame of the two Marco Polo & Marco Polo-R proposals to the ESA Cosmic Vision program. Flagged by ESA as an instrument concept of interest for the mission in 2012, it has been under study for a few years in the frame of a Research and Technology (R&T) development programme between 5 French laboratories (LPC2E, IPAG, LATMOS, LISA, CSNSM) [3,4], partly funded by the French Space Agency (CNES). The work is undertaken in close collaboration with the Thermo Fisher Scientific Company, which commercialises Orbitrap-based laboratory instruments. The R&T activities are currently concentrating on the core elements of the Orbitrap analyser that are required to reach a sufficient maturity level for allowing design studies of future space instruments. A prototype is under development at LPC2E and a mass resolution (m/Δm FWHM) of 100,000 as been obtained at m/z = 150 for a background pressure of 10<sup>-8</sup>mbar. ILMA would be a key instrument to measure the molecular, elemental and isotopic composition of objects such as carbonaceous asteroids, comets, or other bodies devoid of atmosphere such as the surface of an icy satellite, the Moon, or Mercury.
[in2p3-00939470] Dust OrbiTrap Sensor (DOTS) for In-Situ Analysis of Airless Planetary Bodies
Date: 3 juil 2020 - 09:40
[in2p3-00780291] A High Mass-Resolution Orbitrap Mass Spectrometer for In Situ Analysis in Planetary Science: Isotope performance studies
Date: 28 jan 2013 - 12:26
Desc: Solar System exploration is dealing more and more with chemically complex matter, potentially associated with astrobiology or prebiotic‐related science objectives. It requires the development of new space instruments with improved capability to perform the measurements that address the related science goals. Due to its ability to reveal quantitatively the composition of any chemical material, mass spectrometry has served as an invaluable scientific analytical tool. The best mass resolution currently achieved by mass spectrometers in space is about 3,000 at mass 28 (ROSINA on board ESA's comet chaser Rosetta). As mass‐resolving power increases, several new plateaus of chemical information become accessible. Fourier Transform Mass Spectrometry (FT MS) offers (i) the multiple advantages of yielding the entire mass spectrum at once, rather than requiring that each peak be scanned through separately and (ii) in the zero‐collision limit, mass‐resolving power increases directly with data acquisition period. Purely electrostatic orbital traps in laboratory are showing mass resolution above 100,000 for m/z ≤ 400, that provides separation for each detected isobaric species[2,3]. Our French consortium of laboratories, in collaboration with ThermoFischer Scientific, is currently working on the adaptation of this type of mass spectrometer for space instrumentation. It would open exciting new opportunities for molecular characterization, isotopic abundance evaluation, and more generally environmental characterization of the atmospheres and surfaces of planetary bodies. In this presentation, we will describe this innovative concept of mass analyzer for space that is lightweight, uses (pulsed) DC voltages, and provides ultra‐high mass‐resolving power capabilities. Sample preparation, ionization and ion injection is specific for each envisaged space application. Our laboratory prototype uses a UV (337 nm) laser beam for the ablation and ionization of metal and organic samples. A mass resolution of 250,000 at mass 56 has been recently achieved on stainless steel samples. Measurements of the isotopic pattern have been tested with Zirconium doped with Molybdenum samples. The results obtained so far are demonstrating that this instrument has the capability to uniquely address science objectives related to in situ composition measurements, in particular those related to astrobiology, for future planetary missions to airless surfaces bodies as asteroid, comets or to planetary moons.
Direction du LISA
Maison des Sciences de l’Environnement 4ème étage
UPEC Campus Centre
61, avenue du Général de Gaulle
94010 CRETEIL CEDEX
email@example.com / 01.45.17.15.60