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Laboratoire Interuniversitaire des Systèmes Atmosphériques

LISA

Tutelles >

Université Paris Diderot - Paris 7

UFR de rattachement >

UFR Chimie

Label unité >

UMR 7583

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

[bioemco-00396429] Regional variability of the composition of mineral dust from western Africa : results from the AMMA SOP0/DABEX and DODO field campaigns - art. no. D00C13

Date: 30 Jul 2021 - 05:03

Desc: This paper presents data on elemental and mineralogical composition of mineral dust from various source regions of Africa collected during the African Monsoon Multidisciplinary Analyses (AMMA) SOP0/DABEX and Dust Ouflow and Deposition to the Ocean (DODO) DODO1 experiments (January-February 2006), and the DODO2 campaign (August 2006). Bulk filter samples were collected at the AMMA supersite of Banizoumbou, Niger, as well as on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft. Both mineral dust and biomass burning in external mixing occurred in surface and elevated layers during the winter field phase of the campaign. However, mineral dust was overwhelming, accounting for 72% of the estimated aerosol mass in aged elevated biomass burning layers and up to 93% in plumes of mineral dust, which generally occurred in the boundary layer. A number of well-defined episodes of advection of mineral dust could be identified both at the ground and on the aircraft. The elemental and mineralogical composition varied depending on source region. This variability could be well traced by the calcium content, which is enhanced in dust from North Africa but depleted in dust from the Sahel. Iron oxides in the form of hematite and goethite are enriched in dust emitted within Sahel and in Mauritania, whereas dust from the Bodele depression is iron-oxide depleted. Iron oxides represented between 2.4% and 4.5% of the total estimated dust oxide mass. This regional variability will have to be taken into account in estimating the optical properties of absorption of mineral dust from western Africa.

[hal-02347537] New constraints on elemental and Pb and Nd isotope compositions of South American and Southern African aerosol sources to the South Atlantic Ocean

Date: 30 Jul 2021 - 04:58

Desc: Improving the geochemical database available for characterising potential natural and anthropogenic aerosol sources from South America and Southern Africa is a critical precondition for studies aimed at understanding trace metal controls on the marine biogeochemical cycles of the South Atlantic Ocean. We here present new elemental and isotopic data for a wide range of sample types from South America and Southern Africa that are potentially important aerosol sources. This includes road dust from Buenos Aires and lichen samples from Johannesburg, soil dust from Patagonia, volcanic ash from the Andean volcanic belt, and aerosol samples from São Paulo. All samples were investigated for major (Al, Ca, Fe, Mg, Na, K, Mn) and trace element (Cd, Co, Cr, Cu, Ni, Pb, REE, Sc, Th, Y, V, Zn) concentrations and Nd and Pb isotopic compositions. We show that diagrams of 208Pb/207Pb vs. εNd, 208Pb/207Pb vs. Pb/Al, 1/[Pb], Zn/Al, Cd/Al, Cu/Al, and εNd vs. Pb/Al, and 1/[Nd] are best suited to separate South American and South African source regions as well as natural and anthropogenic sources. A subset of samples from Patagonia and the Andes was additionally subjected to separation of a fine (<5 μm) fraction and compared to the composition of the bulk sample. We show that differences in the geochemical signature of bulk samples between individual regions and source types are significantly larger than between grain sizes. Jointly, these findings present an important step forward towards a quantitative assessment of aeolian trace metal inputs to the South Atlantic Ocean.

[insu-00646743] Community Variability of Bacteria in Alpine Snow (Mont Blanc) Containing Saharan Dust Deposition and Their Snow Colonisation Potential

Date: 28 Jul 2021 - 05:04

Desc: Microorganisms uplifted during dust storms survive long-range transport in the atmosphere and could colonize high-altitude snow. Bacterial communities in alpine snow on a Mont Blanc glacier, associated with four depositions of Saharan dust during the period 2006-2009, were studied using 16S rRNA gene sequencing and flow cytometry. Also, sand from the Tunisian Sahara, Saharan dust collected in Grenoble and Mont Blanc snow containing no Saharan dust (one sample of each) were analyzed. The bacterial community composition varied significantly in snow containing four dust depositions over a 3-year period. Out of 61 phylotypes recovered from dusty snow, only three phylotypes were detected in more than one sample. Overall, 15 phylotypes were recognized as potential snow colonizers. For snow samples, these phylotypes belonged to Actinobacteria, Proteobacteria and Cyanobacteria, while for Saharan sand/dust samples they belonged to Actinobacteria, Bacteroidetes, Deinococcus-Thermus and Proteobacteria. Thus, regardless of the time-scale, Saharan dust events can bring different microbiota with no common species set to alpine glaciers. This seems to be defined more by event peculiarities and aeolian transport conditions than by the bacterial load from the original dust source.

[hal-01141731] Characterization of organic tracer compounds in PM2.5 at a semi-urban site in Beirut, Lebanon

Date: 28 Jul 2021 - 05:04

Desc: A measurement campaign was conducted at a semi-urban site located in the suburbs of the city of Beirut (Lebanon) during summertime (2–18 July 2011). The molecular composition of organic PM2.5 was investigated following a chemical derivatization gas chromatography/mass spectrometry technique. Accordingly, several classes of compounds represented by 18 individual organic tracers were determined. These tracers include levoglucosan, a tracer for biomass combustion, dicarboxylic acids, and several tracers for the photo-oxidation of isoprene, α-pinene and β-caryophyllene. The sum of the mean concentrations of the isoprene oxidation products was 4 ng/m3, that of α-pinene was 124 ng/m3 and that of β-caryophyllene was 11 ng/m3. For other tracers of organic aerosols, the highest concentrations were obtained for carboxylic acids with an average value of 939 ng/m3. An average value of 49 ng/m3 was obtained for levoglucosan. Organic and elemental carbon concentrations were measured by a thermo-optical analyzer. Average values were 5.6 and 1.8 μg/m3, respectively. A reconstruction of organic PM2.5 composition suggests that cooking, fossil-fuel combustion, biomass burning, sesquiterpenes, monoterpenes, and isoprene contribute on average about 27 ± 13, 16 ± 7, 5 ± 3, 26 ± 5, 26 ± 13 and < 1 ± 0.3% of PM2.5 organic carbon, respectively.

[hal-02323565] Pluriannual comparisons of satellite-based rainfall products over the Sahelian belt for seasonal vegetation modeling

Date: 28 Jul 2021 - 05:00

Desc: [1] The Sahel corresponds to the transition from the dry arid desert to wet savannahs, where vegetation exhibits a well-marked seasonal cycle in response to the West African Monsoon. Precipitation data sets with high spatial and temporal resolutions are therefore relevant to investigate the dynamics of the Sahelian vegetation. Three satellite-based precipitation products (TRMM3B42, RFE2.0, and CMORPH) are compared and tested against kriged rain gauge measurements. The objective is to evaluate their capability to retrieve the main precipitation characteristics during the rainy season. Comparisons are performed over a 4 year period (2004-2007) at spatial resolutions of 0.25°× 0.25°or 0.5°× 0.5°by looking at sensitive criteria for vegetation: spatial distribution of the rainfall field, precipitation frequency, dry spell distribution, and precipitation amounts. Intercomparisons between satellite data sets are conducted over the Sahelian belt (10°N-20°N; 20°W-35°E) at a 1-10 day time scale, while comparisons with 10 day kriged rain gauge measurements are performed over a smaller area (10°N-17.5°N; 17.5°W-2.5°E). The precipitation spatial distributions are in good agreement between satellite products and with the kriged data. Considering the daily frequency, the satellite products show a high agreement between them (∼80%). The TRMM3B42 product exhibits the lowest number of rainy days, and RFE2.0 exhibits the highest. The CMORPH product overestimates rainfall amounts, while TRMM3B42 and RFE2.0 are both in good agreement with the kriged data. The impacts of these distinctive behaviors on simulated vegetation are investigated by comparisons with MODIS LAI, considering vegetation dynamics and amounts. The studied criteria of precipitation fields appear as a critical issue for Sahelian vegetation modeling. Citation: Pierre, C., G. Bergametti, B. Marticorena, E. Mougin, T. Lebel, and A. Ali (2011), Pluriannual comparisons of satellite-based rainfall products over the Sahelian belt for seasonal vegetation modeling,