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
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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
The Polar Ozone and Aerosol Measurement instrument
1996
Auteurs : R. M. BEVILACQUA, Colette Brogniez, E Chassefière, D-T Chen, F. DALAUDIER, D. J. DEBRESTIAN, C. DENIEL, M.D. Fromm, W. GLACCUM, J. S. HORNSTEIN, R. KREMER, S. S. KRIGMAN, Jacqueline LENOBLE, R. L. LUCKE, J. D. Lumpe, J. J. OLIVERO, C. E. Randall, D W Rusch et E. P. SHETTLE
Masquer le résumé
The second Polar Ozone and Aerosol Measurement instrument (POAM II) is a spaceborne experiment designed to measure the vertical profiles of ozone, water vapor, nitrogen dioxide, aerosol extinction, and temperature in the polar stratosphere and upper troposphere with a vertical resolution of about 1 km. Measurements are made by the solar occultation technique. The instrument package, which has a mass of less than 25 kg, is carried on the Satellite Pour l'Observation de la Terre (SPOT) 3 spacecraft and has a design lifetime of 3-5 years. POAM II has provided data on the south polar ozone hole, north and south polar ozone phenomena, the spatial and temporal variability of stratospheric aerosols and polar stratospheric clouds, and has detected polar mesospheric clouds.
Keywords :
Photometer ; Design ; Data acquisition ; Data analysis ; Vertical profile ; Satellite observation ; Ozone ; Vapor ; Water ; Nitrogen dioxide ; Aerosols ; Atmospheric temperature ; Troposphere ; Stratosphere ; Polar region ; Spaceborne instruments ;
Source : Pascal - INIST  

Characterization of aerosols from simulated SAGE III measurements applying two retrieval techniques
2000
Auteurs : J. ANDERSON, Colette Brogniez, L. CAZIER, Jacqueline LENOBLE, M. P. Mccormick et V. K. SAXENA
Masquer le résumé
We investigated the retrieval of aerosol properties and the extinction due to aerosols at the ozone and water vapor channels from simulated measurements at variations of the planned Stratospheric Aerosol and Gas Experiment (SAGE) III aerosol channels. The aerosol quantities surface area, volume, and effective radius are retrieved through the application of two distinct algorithms in the form of the randomized-minimization-search technique (RMST) and the constrained linear inversion (CLI) method. These aerosol quantities are important as inputs in climate, photochemical, and radiative forcing models and are useful in comparing diverse measurements. Ten analytical size distributions fitted to aerosol populations measured in situ are used with a Mie scattering code in conjunction with a Monte Carlo technique to simulate SAGE III measurements. These models consist of variations of prevolcanic and postvolcanic size distributions that exhibit various spectral shapes. Neither the complex components nor the uncertainties of the refractive indices are considered. We developed an objective scheme to estimate the systematic, random, and total uncertainties of each retrieved quantity that considers the contribution of the particles that lie outside the retrieved size range. Results, based on the 10 selected aerosol models, indicate that in the seven-eight SAGE III channel retrievals, both algorithms obtain estimated total errors in the range 8-50% for the surface area with an average total error (R*) of ∼25%; for the volume the range is 5-25% with an R* of ∼12%, and for the effective radius, the range is 6-36% with an R* of 20% though both inversion techniques are applied in different size ranges. The inversion of the six longest channels to study aerosol properties in both the lower stratosphere and the upper troposphere leads to RMST R* values of ∼32, ∼15, and ∼20% and CLI R* values of ∼48, ∼22, and ∼31% for the surface area, volume, and effective radius, respectively. In the seven wavelength retrievals, both algorithms retrieved the extinction coefficients at the unused channel to within their measurement uncertainties except at the 0.385 and 1.550 μm channels located at the tail ends of the SAGE III aerosol extinction spectrum. The calculated extinction due to aerosols at the water vapor channel at 0.940 μm and the ozone channel at 0.600 μm produced R* values of <10 and <15% for both techniques. We have shown that the application of either technique, when properly tailored to the SAGE III system, not only can obtain useful aerosol information in most cases but also can estimate reasonably the extinction due to aerosols at other wavelengths within the SAGE III wavelength range.
Keywords :
Space remote sensing ; Algorithm ; Stratospheric aerosol ; Numerical simulation ; Particle size distribution ; Uncertainty ; Extinction index ; Volume ; Effective radius ; Surface area ; Inversion ; Computing method ; Spaceborne instruments ;
Source : Pascal - INIST  

Measurement errors in cirrus cloud microphysical properties
1998
Auteurs : H. Chepfer, Guy FEBVRE, B. GERARD, Jean-François Gayet et H. Larsen
Masquer le résumé
The limited accuracy of current cloud microphysics sensors used in cirrus cloud studies imposes limitations on the use of the data to examine the cloud's broadband radiative behaviour, an important element of the global energy balance. We review the limitations of the instruments, PMS probes, most widely used for measuring the microphysical structure of cirrus clouds and show the effect of these limitations on descriptions of the cloud radiative properties. The analysis is applied to measurements made as part of the European Cloud and Radiation Experiment (EUCREX) to determine mid-latitude cirrus microphysical and radiative properties.
Keywords :
Source : HAL  

Scientific UV data management
SUVDAMA
1996 - 1999

Sujets :
Measurement Methods, Environmental Protection, Forecasting, Meteorology
Participants :
Laboratoire d'Optique Atmosphèrique
Laboratoire d'Optique Atmosphèrique


Royal Netherlands Meteorological Institute
Royal Netherlands Meteorological Institute


Belgian Institute for Space Aeronomy
Belgian Institute for Space Aeronomy


FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V. DEUTSCHLAND
FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Research

INSTITUT FUER ATMOSPHAERISCHE UMWELTFORSCHUNG EV Kreuzeckbahnstrasse 19 82467
DEUTSCHLAND
NATURAL ENVIRONMENT RESEARCH COUNCIL UNITED KINGDOM
NATURAL ENVIRONMENT RESEARCH COUNCIL
Research,Other

BRITISH ANTARCTIC SURVEY Madingley Road, High Cross CB3 0ET
UNITED KINGDOM
University of Manchester Institute of Science and Technology UNITED KINGDOM
University of Manchester Institute of Science and Technology
Education

Department of Pure and Applied Physics PO Box 88 Sackville Street M60 1QD
UNITED KINGDOM
ARISTOTLE UNIVERSITY OF THESSALONIKI HELLAS
ARISTOTLE UNIVERSITY OF THESSALONIKI
Education

DEPARTMENT OF PHYSICS LABORATORY OF ATMOSPHERIC PHYSICS PO Box 149 Aristotle University of Thessaloniki 54006
HELLAS
FINNISH METEOROLOGICAL INSTITUTE SUOMI/FINLAND
FINNISH METEOROLOGICAL INSTITUTE
Research

PO Box 503 Vuorikatu 24 00101
SUOMI/FINLAND
Instituto Nacional de Meteorología ESPAÑA
Instituto Nacional de Meteorología
Non Commercial

Centro Meteorologico de Canarias Occidental Estacion de Vigilancia Atmosferica deIzana PO Box 38071 77,Calle San Sebastian 38071
ESPAÑA
NATIONAL INSTITUTE OF PUBLIC HEALTH AND ENVIRONMENT NEDERLAND
NATIONAL INSTITUTE OF PUBLIC HEALTH AND ENVIRONMENT
Research

LABORATORY OF RADIATION RESEARCH PO Box 1 9,Antonie van Leeuwenhoeklaan 9 3720 BA
NEDERLAND
SWEDISH METEOROLOGICAL AND HYDROLOGICAL INSTITUTE SVERIGE
SWEDISH METEOROLOGICAL AND HYDROLOGICAL INSTITUTE
Other

P.O. Box 60101 Folkborgsvägen 1 601 76
SVERIGE
UNIVERSITAET FUER BODENKULTUR WIEN ÖSTERREICH
UNIVERSITAET FUER BODENKULTUR WIEN
Education,Other

INSTITUT FÜR METEOROLOGIE UND PHYSIK 18,Turkenschanzstrasse 18 1180
ÖSTERREICH
LEOPOLD-FRANZENS-UNIVERSITAET INNSBRUCK ÖSTERREICH
LEOPOLD-FRANZENS-UNIVERSITAET INNSBRUCK
Education

INSTITUTE OF MEDICAL PHYSICS 44,Müllerstrasse 44 6020
ÖSTERREICH
COMMISSION OF THE EUROPEAN COMMUNITIES ITALIA
COMMISSION OF THE EUROPEAN COMMUNITIES
Research,Other

INSTITUTE FOR ENVIRONMENT AND SUSTAINABILITY Via Enrico Fermi 1, TP 460 21020
ITALIA
NORUT INFORMATION TECHNOLOGY LTD. NORGE
NORUT INFORMATION TECHNOLOGY LTD.
Research

Forskningsparken Brelvik 9291
NORGE
KARL-FRANZENS-UNIVERSITAET GRAZ ÖSTERREICH
KARL-FRANZENS-UNIVERSITAET GRAZ
Education

INSTITUTE OF METEOROLOGY AND GEOPHYSICS - FACULTY OF SCIENCE 1,Halbarthgasse 1 8010
ÖSTERREICH
NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY NORGE
NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
Education,Other

THE COLLEGE OF ARTS AND SCIENCE DEPARTMENT OF PHYSICS - FACULTY OF INFORMATICS, PHYSICS AND MATHEMATICS Hoegskoleringen 5 7491
NORGE
Università degli Studi di Roma La Sapienza ITALIA
Università degli Studi di Roma La Sapienza
Education

Facoltà di Scienze Matematiche, Fisiche e Naturali Istituto di Fisica Piazzale Aldo Moro 2/5 00185
ITALIA
Hide objectives
The overall goal is to initiate a scientific interpretation of the existing ground-based spectral UV measurements in Europe on the basis of an improved understanding of the radiative transfer processes. This will be realised by means of close interactions between the modelling and the measuring scientific communities by comparing the results of improved radiative transfer modelling calculations with quality-controlled UV measurements performed by stationary instruments at various sites in Europe. The following objectives will be addresses in this project: - to improve the existing radiative transfer models especially in cloudy and variable sky conditions. - to develop the scientific tools to be able to offer valuable responses to specific user's questions such as validity of geographically interpolated UV measurements, trends of biologically weighted UV, daily UV-doses, seasonal variations, etc. - to define the scientific tools and procedures for establishing an experimental 'database' for measured spectral UV-irradiance in Europe. - to define the type and the procedures for ancillary measurements and to continue the implementation of the quality-assurance and quality-control procedures.

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  

Characteristics of the UV radiation field in the Alps
1998 - 2000

Sujets :
Meteorology, Forecasting, Measurement Methods, Environmental Protection
Participants :
Laboratoire d'Optique Atmosphèrique
Laboratoire d'Optique Atmosphèrique


LEOPOLD-FRANZENS-UNIVERSITAET INNSBRUCK ÖSTERREICH
LEOPOLD-FRANZENS-UNIVERSITAET INNSBRUCK
Education

INSTITUTE OF MEDICAL PHYSICS 44,Müllerstrasse 44 6020
ÖSTERREICH
FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V. DEUTSCHLAND
FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Research

INSTITUT FUER ATMOSPHAERISCHE UMWELTFORSCHUNG EV Kreuzeckbahnstrasse 19 82467
DEUTSCHLAND
UNIVERSITAET FUER BODENKULTUR WIEN ÖSTERREICH
UNIVERSITAET FUER BODENKULTUR WIEN
Education,Other

INSTITUT FÜR METEOROLOGIE UND PHYSIK 18,Turkenschanzstrasse 18 1180
ÖSTERREICH
UNIVERSITE JOSEPH FOURIER - GRENOBLE 1 FRANCE
UNIVERSITE JOSEPH FOURIER - GRENOBLE 1
Education

EQUIPE INETERACTIONS RAYONNEMENT SOLAI RE ATMOSPHÈRE Quai Claude Bernard 17 38000
FRANCE
Physikalisch-Meteorologisches Observatorium Davos SCHWEIZ/SUISSE/SVIZZERA
Physikalisch-Meteorologisches Observatorium Davos
Research

Weltstrahlungszentrum 33,Dorfstraße 7260
SCHWEIZ/SUISSE/SVIZZERA

Source : Cordis  





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