LOA - Laboratoire d'Optique Atmosphèrique - UMR 8518

France Centre de recherche public
Accréditation CIR
Contact principal
Téléphone : 33(0)3 20 43 45 32
Mail : direction-loa@univ-lille1.fr
Adresse :
Bât. P5
59655 Villeneuve d'Ascq
France
Consultez cette fiche en intégralité ?
Consultez cette fiche et près de 50 000 autres fiches de Centres de Recherche dans plus de 30 pays européens sur Expernova.com !

Inscrivez-vous ou contactez-nous pour une démonstration personnalisée.
Description
(Extrait du site web)
Activité Générale :

L'optique atmosphérique cherche à modéliser la propagation à travers l'atmosphère de la lumière visible reçue du soleil et de la lumière infrarouge émise par l'ensemble des surfaces et de l'atmosphère terrestres. Les travaux menés au LOA dans ce domaine s'insèrent dans l'étude globale du climat.

Un premier objectif est de quantifier le rôle de ce rayonnement visible et infrarouge dans les échanges énergétiques de la planète, en particulier de préciser le rôle des nuages dans le bilan radiatif de la terre dont ils constituent un facteur essentiel.

Un second axe de recherche porte sur la caractérisation à l'échelle du globe de différents paramètres qui sont en relation directe avec l'évolution climatique (nuages, aérosols, surfaces), en utilisant principalement l'observation satellitaire.
Les travaux menés dans ce contexte mettent en oeuvre:

* La conception de logiciels permettant de simuler le transfert du rayonnement, à l'aide de modèles du système terre - atmosphère.
* L'analyse d'observations acquises par les capteurs satellitaires existants, le plus souvent sous forme d'images traitées sur ordinateur, et la conception d'expériences satellitaires nouvelles.
* La réalisation de campagnes d'observation de terrain, utilisant des appareillages développés par le laboratoire, mis en oeuvre au sol ou à partir d'avions ou de ballons stratosphériques, et destinés à valider les modèles ou à mettre en évidence les processus atmosphériques.

Le LOA est une unité Mixte de Recherches (UMR/CNRS 8518). Il fait partie de la Fédération de Recherches (FR1818) Milieux naturels et anthropisé Flux et dynamique.

Quelques documents de Laboratoire d'Optique Atmosphèrique
Verification of aerosol models for satellite ocean color remote sensing
1998
Auteurs : P.-Y. DESCHAMPS, Robert J. FROUIN et M. SCHWINDLING
Masquer le résumé
Direct atmospheric transmittance and sky radiance were measured spectrally at the coastal site of Scripps Institution of Oceanography pier in La Jolla, California, during the winters of 1993 and 1994. Direct atmospheric transmittance was also measured aboard R/V Wecoma and on Catalina Island during the 1994 California Cooperative Oceanic Fisheries Investigation winter cruise. The data were analyzed to (1) verify whether the aerosol models selected by Gordon and Wang [1994] for the sea-viewing wide field of view sensor are adequate for ocean color remote sensing from space and (2) identify what type of in situ atmospheric optics measurements should be performed to verify atmospheric correction algorithms. Aerosol optical thickness at 870 nm was generally low at La Jolla, with most values below 0.1 after correction for stratospheric aerosols. Values were even lower offshore (R/V Wecoma, Catalina Island), and no systematic correlation was found between aerosol characteristics and meteorological conditions. Therefore a mean background model, specified regionally, may be sufficient for ocean color remote sensing from space. For optical thicknesses above 0.1, two modes of variability characterized by Ångström coefficients of 1.2 and 0.5 and corresponding to tropospheric and maritime models, respectively, were identified in the measurements. The aerosol models selected by Gordon and Wang [1994] allow one to fit, within measurement inaccuracies, the derived values of Ångström coefficient and pseudo phase function (the product of single-scattering albedo and phase function), key atmospheric correction parameters. Importantly, the pseudo phase function can be derived from measurements of the Ångström coefficient. This means that shipborne Sun photometer measurements made at the time of satellite overpass are usually sufficient to verify the atmospheric correction of ocean color.
Keywords :
Air sea interface ; Aerosols ; Sea surface ; Remote sensing ; Transmittance ; Optical thickness ; Atmospheric correction ;
Source : Pascal - INIST  

In-flight calibration of the POLDER polarized channels using the sun's glitter
1999
Auteurs : T. BAILLEUL, J.-L. Deuzé, O. HAGOLLE, M. HERMAN, Goloub PHILLIPPE et B. TOUBBE
Pas de résumé disponible
Keywords :
remote sensing ; polarization ; calibration ; reflectance ; roughness ; radiance ; accuracy ; satellite methods ; airborne methods ; atmosphere ; aerosols ; errors ;
Source : Pascal - INIST  

Ground measurements of the polarized bidirectional reflectance of snow in the near-infrared spectral domain : Comparisons with model results
1998
Auteurs : J.-L. Deuzé, M. FILY, Michel Fily, C. LEROUX, C Leroux, Goloub PHILLIPPE, C. SERGENT et C. SERGENT
Masquer le résumé
Ground-based measurements were carried out in the French Alps in March 1995 to study the bidirectional and polarized bidirectional reflectances of various snow covers. Atmospheric (optical thickness) and snow characteristics (grain size and type) were measured simultaneously. The ground reflectance data are compared with snow reflectance modeling results. A radiative transfer model based on the adding-doubling method is used to compute the snow reflectance. The single-scattering parameters are determined by a Mie or a ray-tracing code depending on the particle shape introduced in the model (spherical or hexagonal ice particles). Special attention is paid to the comparisons in the near-infrared spectral range (1.65 μm) because of the sensitivity of snow reflectance to the grain size and shape. In the visible and near-infrared domains of the solar spectrum, the amplitude of the polarized signal is very low and independent of the snow grain size. The agreement between measurements and model results is good if hexagonal particles are introduced in the model instead of the spherical snow grains commonly used in reflectance studies.
Keywords :
Snow cover ; Ground based measurement ; Solar radiation ; Radiation polarization ; Polarimetry ; Near infrared spectrum ; Reflectance ; Radiative transfer ; Observation data ; Comparative study ; Particle shape ; Grain size ; Alps ; France ; Bidirectional reflectance model ; Europe ;
Source : Pascal - INIST  

Cirrus microphysical properties and their effect on radiation : survey and integration into climate models using combined satellite observations (CIRAMOSA)
CIRAMOSA
2001 - 2003

Sujets :
Measurement Methods, Environmental Protection, Resources of the Sea, Fisheries, Meteorology, Forecasting
Participants :
Laboratoire de Météorologie Dynamique
Laboratoire de Météorologie Dynamique


Laboratoire d'Optique Atmosphèrique
Laboratoire d'Optique Atmosphèrique


CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE FRANCE
CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
Research

URA 0713 - LABORATOIRE D'OPTIQUE ATMOSPHÉRIQUE Laboratoire d'Optique Atmosphérique (URA 713) UER de Physique Fondamentale Université de Lille 59655
FRANCE
SECRETARY OF STATE FOR DEFENCE - MINISTRY OF DEFENCE UNITED KINGDOM
SECRETARY OF STATE FOR DEFENCE - MINISTRY OF DEFENCE
Research

METEOROLOGICAL OFFICE HADLEY CENTRE FOR CLIMATE PREDICTION AND RESEARCH Fitzroy Road, Metz Office EX1 3PB
UNITED KINGDOM
Hide objectives
The radiation effect due to changes of microphysical properties within cirrus clouds can be very important. We will provide a long-term survey of these properties, together with cirrus macrophysical properties, and then establish a compilation of correlations between them and the state of the atmosphere. This information is essential for the understanding of changes in clouds expected by a global climate change. Satellite instruments measuring radiation with a good spectral resolution as well as multi-angular measurements of polarized reflectance used with newly developed retrieval algorithms are now capable to give this information over the whole globe. Extensive care will be taken of the validation of the retrieved cirrus properties by intercomparison with data sets from regional measurement campaigns. Models for climate prediction can profit from the outcome of this proposal by using the most appropriate correlations in their radiation codes.

Source : Cordis  

Remote sensing of cirrus radiative parameters during EUCREX'94. Case study of 17 April 1994. Part II : Microphysical models
1999
Auteurs : Gérard BROGNIEZ, H. Chepfer, P. H. FLAMANT, Philippe Flamant, J. PELON, L. SAUVAGE, L. Sauvage et V. TROUILLET
Masquer le résumé
In this paper, a quantitative analysis of in situ and radiative measurements concerning cirrus clouds is presented. These measurements were performed during the European Cloud and Radiative Experiment 1994 (EUCREX'94) as discussed in an earlier paper (Part I). The analyses are expressed in terms of cirrus microphysics structure. The complex microphysical structure of cirrus cloud is approximated by simple hexagonal monocrystalline particles (columns and plates) and by polyerystalline particles (randomized triadic Koch fractals of second generation) both arbitrarily oriented in space (3D). The authors have also considered hexagonal plates randomly oriented in horizontal planes with a tilted angle of 15° (2D). Radiative properties of cirrus cloud are analyzed. assuming that the cloud is composed of 3D ice crystals, by way of an adding-doubling code. For the hypothesis of 2D ice crystals, a modified successive order of scattering code has been used. The first order of scattering is calculated exactly using the scattering phase function of 2D crystals; for the higher orders, it is assumed that the same particles are 3D oriented. To explain the whole dataset, the most appropriate microphysics, in terms of radiative properties of cirrus clouds, is that of the 2D hexagonal plates whose aspect ratio (length divided by diameter) is 0.05.
Keywords :
Cirrus ; Radiative properties ; Optical properties ; Satellite observation ; Aircraft observation ; Ice crystals ; Polycrystalline ice ; Hexagonal crystals ; Case study ; France ; East Atlantic ; Europe ;
Source : Pascal - INIST  

Global and regional Earth-system monitoring using satellite and in-situ data
GEMS
2005 - 2009

Sujets :
Earth Sciences, Environmental Protection, Meteorology, Aerospace Technology
Participants :
Laboratoire d'Optique Atmosphèrique
Laboratoire d'Optique Atmosphèrique


European Centre for Medium-Range Weather Forecasts
European Centre for Medium-Range Weather Forecasts


Danish Meteorological Institute
Danish Meteorological Institute


National Technical University of Athens
National Technical University of Athens


Arpa Emilia Romagna
Arpa Emilia Romagna


Deutscher Wetterdienst
Deutscher Wetterdienst


COMMISSARIAT À L'ENERGIE ATOMIQUE FRANCE
COMMISSARIAT À L'ENERGIE ATOMIQUE
Research

LABORATOIRE DES SCIENCES DU CLIMAT ET DE L'ENVIRONMENT JOINT RESEARCH UNIT CEA-CNRS 1572' 31/33 rue de la Federation
FRANCE
IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE UNITED KINGDOM
IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
Education

EPIDEMIOLOGY & PUBLIC HEALTH, DIVISION OF PRIMARY CARE & POPULATION HEALTH SCIENCES Exhibition Road
UNITED KINGDOM
MAX PLANCK GESELLSCHAFT ZUR FÖRDERUNG DER WISSENSCHAFTEN E.V. DEUTSCHLAND
MAX PLANCK GESELLSCHAFT ZUR FÖRDERUNG DER WISSENSCHAFTEN E.V.
Other,Research

MAX-PLANCK-INSTITUT FÜR METEOROLOGIE Postfach 101062 Hofgartenstrasse 8
DEUTSCHLAND
ROYAL NETHERLANDS METEOROLOGICAL INSTITUTE NEDERLAND
ROYAL NETHERLANDS METEOROLOGICAL INSTITUTE
Other

DEPARTMENT OF CLIMATE RESEARCH AND SEISMOLOGY PO Box 201 Wilhlminalaan 10
NEDERLAND
INSTITUT D'AERONOMIE SPATIALE DE BELGIQUE BELGIQUE-BELGIË
INSTITUT D'AERONOMIE SPATIALE DE BELGIQUE
Research

IASB/BIRA 3 Avenue Circulaire
BELGIQUE-BELGIË
FINNISH METEOROLOGICAL INSTITUTE SUOMI/FINLAND
FINNISH METEOROLOGICAL INSTITUTE
Research

RESEARCH DEPARTMENT PO Box 503 Vuorikatu 24
SUOMI/FINLAND
UNIVERSITY OF BREMEN DEUTSCHLAND
UNIVERSITY OF BREMEN
Education

UNIVERSITY OF BREMEN, DEP. OF PHYSICS (FBI), INST. OF ENVIRON. PHYSICS AND REMOTE SENSING (IUP/IFE) Postfach 330440 Bibliotheksstrasse
DEUTSCHLAND
UNIVERSITE PIERRE ET MARIE CURIE FRANCE
UNIVERSITE PIERRE ET MARIE CURIE
Education

SERVICE D'AÉRONOMIE - UPMC - TOUR 45-46 (BOITE 102) 4, Place Jussieu
FRANCE
METEO-FRANCE, CENTRE NATIONAL DE RECHERCHES METEOROLOGIQUES FRANCE
METEO-FRANCE, CENTRE NATIONAL DE RECHERCHES METEOROLOGIQUES
Research

CENTRE NATIONAL DE RECHERCHES METEOROLOGIQUES Avenue Gaspard Coriolis, 42
FRANCE
NATIONAL UNIVERSITY OF IRELAND, GALWAY ÉIRE/IRELAND
NATIONAL UNIVERSITY OF IRELAND, GALWAY
Education

ENVIRONMENTAL CHANGE INSTITUTE University Road
ÉIRE/IRELAND
KONINKLIJK METEOROLOGISCH INSTITUUT - INSTITUT ROYAL METEOROLOGIQUE BELGIQUE-BELGIË
KONINKLIJK METEOROLOGISCH INSTITUUT - INSTITUT ROYAL METEOROLOGIQUE
Research

DEPARTMENT OF OBSERVATIONS Ringlaan 3
BELGIQUE-BELGIË
CONSIGLIO NAZIONALE DELLE RICERCHE ITALIA
CONSIGLIO NAZIONALE DELLE RICERCHE
Research

INSTITUTO DI SCIENZE DELL'ATMOSFERA E DEL CLIMA, ISAC-CNR' Piazzale Aldo Moro 7
ITALIA
METEOROLOGISK INSTITUTT NORGE
METEOROLOGISK INSTITUTT
Research

RESEARCH AND DEVELOPMENT DEPARTMENT, AIR POLLUTION SECTION Niels Henrik Abels vei 40
NORGE
RHENISH INSTITUTE FOR ENVIRONMENTAL RESEARCH AT THE UNIVERSITY OF COLOGNE DEUTSCHLAND
RHENISH INSTITUTE FOR ENVIRONMENTAL RESEARCH AT THE UNIVERSITY OF COLOGNE
Research

DATA ASSIMILATION RESEARCH GROUP Aachener Strasse 201 -209
DEUTSCHLAND
EUROPEAN COMMISSION, GENERAL DIRECTORATE JOINT RESEARCH CENTRE ITALIA
EUROPEAN COMMISSION, GENERAL DIRECTORATE JOINT RESEARCH CENTRE
Research

CLIMATE CHANGE UNIT OF THE INSTITUE FOR ENVIRONMENT AND SUSTAINABILITY Via E. Fermi, 1
ITALIA
INSTITUT NATIONAL DE L'ENVIRONNEMENT INDUSTRIEL ET RISQUES FRANCE
INSTITUT NATIONAL DE L'ENVIRONNEMENT INDUSTRIEL ET RISQUES
Research

CHRONIC RISKS DIVISION Parc Technologique Alata
FRANCE
CZECH HYDROMETEOROLOGICAL INSTITUTE CESKA REPUBLIKA
CZECH HYDROMETEOROLOGICAL INSTITUTE
Other

CZECH HYDROMETEOROLOGICAL INSTITUTE Na Sabatce 17
CESKA REPUBLIKA
ENVIRONMENTAL PROTECTION AGENCY IRELAND ÉIRE/IRELAND
ENVIRONMENTAL PROTECTION AGENCY IRELAND
Other

ERTDI PROGRAMME, ENVIRONMENTAL PROTECTION AGENCY IRELAND PO Box 3000 Johnstown Castle Estate
ÉIRE/IRELAND
MET OFFICE UNITED KINGDOM
MET OFFICE
Other

MET OFFICE HADLEY CENTRE FOR CLIMATE PREDICTION AND RESEARCH Fitzroy road
UNITED KINGDOM
POLISH INSTITUTE OF ENVIRONMENTAL PROTECTION POLSKA
POLISH INSTITUTE OF ENVIRONMENTAL PROTECTION

DEPARTMENT OF ENVIRONMENTAL POLICY - SECTION OF INTEGRATED MODELLING AIR POLLUTION MONITORING DIVISION Krucza 5/11
POLSKA
FORSCHUNGSZENTRUM JUELICH GMBH DEUTSCHLAND
FORSCHUNGSZENTRUM JUELICH GMBH

INSTITUTE OF CHEMISTRY AND DYNAMICS OF THE GEOSPHERE, TROPOSPHERE (ICG II)
DEUTSCHLAND
THE PROVOST, FELLOWS AND SCHOLARS OF THE COLLEGE OF THE HOLY AND UNDIVIDED TRINITY OF QUEEN ELIZABETH, NEAR DUBLIN (HEREINAFTER CALLED TCD) ÉIRE/IRELAND
THE PROVOST, FELLOWS AND SCHOLARS OF THE COLLEGE OF THE HOLY AND UNDIVIDED TRINITY OF QUEEN ELIZABETH, NEAR DUBLIN (HEREINAFTER CALLED TCD)

DEPARTMENT OF CIVIL STRUCTURAL & ENVIRONMENT ENGINEERING 2 College Green
ÉIRE/IRELAND
Hide objectives
Fifteen thousand excess deaths in the heat wave of summer 2003 showed that Europe lacks operational capabilities to provide adequate medium-range (3-7 day) & short-range (1-3 day) forecasts for natural disasters involving atmospheric chemistry & dy namics. This proposal, GEMS, will create new European operational capabilities for medium-range & short-range air-chemistry forecasts, through much improved exploitation of satellite data. The GEMS consortium comprises ten regional centres, most with o perational responsibilities for regional air-quality forecasting, ten leading research labs with capabilities & models on all aspects of atmospheric chemistry, two leading European labs, ECMWF with global operational weather capabilities, & the E U's JRC with global diagnostic capabilities. The research teams & ECMWF will develop a global operational medium-range forecast / assimilation capability for dynamics & composition, exploiting all available satellite data. The global forecasts wil l provide key information on long-range transport of air pollutants to the regional forecast models, through the forecast boundary conditions used by the regional systems. The improved regional forecasts will be used by air-quality authorities at city leve l, in dozens of cities across Europe. Based on the best science, the integrated forecast / assimilation capability will provide a powerful monitoring capability for greenhouse gases, reactive gases and aerosols. Sophisticated new inversion methods will be developed to infer surface fluxes of CO2 and other species through use of the surface flask data with the gridded atmospheric fields on transport & composition. The GEMS project will produce global retrospective analyses of the atmospheric dynamics and composition for the troposphere & stratosphere, and will be able to assess the impact of changes both on global & regional scale, examining extremes as well as means. The real-time & retros

Source : Cordis  

POLDER observations of cloud bidirectional reflectances compared to a plane-parallel model using the International Satellite Cloud Climatology Project cloud phase functions
1998
Auteurs : Jean-Claude BURIEZ, J. DESCLOITRES, Y. FOUQUART et Frédéric PAROL
Masquer le résumé
This study investigates the validity of the plane-parallel cloud model and in addition the suitability of water droplet and ice polycrystal phase functions for stratocumulus and cirrus clouds, respectively. To do that, we take advantage of the multidirectional viewing capability of the Polarization and Directionality of the Earth's Reflectances (POLDER) instrument which allows us to characterize the anisotropy of the reflected radiation field. We focus on the analysis of airborne-POLDER data acquired over stratocumulus and cirrus clouds during two selected flights (on April 17 and April 18, 1994) of the European Cloud and Radiation Experiment (EUCREX'94) campaign. The bidirectional reflectances measured in the 0.86 μm channel are compared to plane-parallel cloud simulations computed with the microphysical models used by the International Satellite Cloud Climatology Project (ISCCP). Although clouds are not homogeneous plane-parallel layers, the extended cloud layers under study appear to act, on average, as a homogeneous plane-parallel layer. The standard water droplet model (with an effective radius of 10 μm) used in the ISCCP analysis seems to be suitable for stratocumulus clouds. The relative root-mean-square difference between the observed bidirectional reflectances and the model is only 2%. For cirrus clouds, the water droplet cloud model is definitely inadequate since the rms difference rises to 9%; when the ice polycrystal model chosen for the reanalysis of ISCCP data is used instead, the rms difference is reduced to 3%.
Keywords :
Cloud physics ; Cirrus ; Stratocumulus cloud ; Parallel plane ; Models ; Validity ; Phase function ; Droplet ; Ice crystals ; Polycrystal ; Aircraft observation ; Image analysis ; East Atlantic ; Bidirectional reflectance model ;
Source : Pascal - INIST  





Automated Data Collection Terms