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
Determination of standards for a UV-B monitoring network
1991 - 1994

Sujets :
Safety, Environmental Protection
Participants :
Laboratoire d'Optique Atmosphèrique
Laboratoire d'Optique Atmosphèrique


Department of Meteorology
Department of Meteorology


Belgian Institute for Space Aeronomy
Belgian Institute for Space Aeronomy


Aristotle University of Thessaloniki
Aristotle University of Thessaloniki


Natural Environment Research Council
Natural Environment Research Council


University of Cambridge
University of Cambridge


University of Tromsø
University of Tromsø


Koninklijk Nederlands Meteorologisch Instituut
Koninklijk Nederlands Meteorologisch Instituut


Leopold-franzens-universitaet Innsbruck
Leopold-franzens-universitaet Innsbruck


Universitaet Fuer Bodenkultur Wien
Universitaet Fuer Bodenkultur Wien


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
University of Tromsø NORGE
University of Tromsø
Education

Institute of Mathematical and Physical Sciences 9037
NORGE
NATURAL ENVIRONMENT RESEARCH COUNCIL UNITED KINGDOM
NATURAL ENVIRONMENT RESEARCH COUNCIL
Research,Other

BRITISH ANTARCTIC SURVEY Madingley Road, High Cross CB3 0ET
UNITED KINGDOM
Koninklijk Nederlands Meteorologisch Instituut NEDERLAND
Koninklijk Nederlands Meteorologisch Instituut
Non Commercial

Division of Physical Meterology PO Box 201 3730 AE
NEDERLAND
University of Cambridge UNITED KINGDOM
University of Cambridge
Education

Department of Botany Downing Street CB2 3ET
UNITED KINGDOM
LEOPOLD-FRANZENS-UNIVERSITAET INNSBRUCK ÖSTERREICH
LEOPOLD-FRANZENS-UNIVERSITAET INNSBRUCK
Education

INSTITUTE OF MEDICAL PHYSICS 44,Müllerstrasse 44 6020
ÖSTERREICH
UNIVERSITAET FUER BODENKULTUR WIEN ÖSTERREICH
UNIVERSITAET FUER BODENKULTUR WIEN
Education,Other

INSTITUT FÜR METEOROLOGIE UND PHYSIK 18,Turkenschanzstrasse 18 1180
ÖSTERREICH
Hide objectives
The overall objective of this project is to produce practical recommendations for the deployment of an integrated ultraviolet B(UVB) network throughout Europe.
Hide achievements
The main results of these campaigns are summarised below 1. Good calibration procedures are a necessary first step for accurate and reliable measurements. Careful monitoring of the lamp current ensures consistency of the calibration source, the lamp-spectrometer geometry must be rigorously maintained, and stray light within the calibration room must be excluded. 2. The spectrometer geometry and mechanical stability must allow the calibration to remain valid between the fixed conditions of the calibration room and the different instrument orientations, spatial distributions of radiation and ambient conditions in the environment. In most cases this involves at least a temperature stabilisation of sensitive parts of the spectrometer. 3. Important characteristics of the ideal spectrometer are: (a) wavelength specification. This could be achieved to an accuracy of about 0.1 to 0.3nm in many of the instruments and is acceptable unless very accurate work in the short wavelength UV-B region of the spectrum is required. (b) slit function. This determines the near field stray light from adjacent wavelengths which is attributed to the nominated wavelength of a measurement. The slit function is important where the measured spectrum changes very rapidly with wavelength, as with solar UV-B. Measuring the slit function of the spectrometers allowed the effects of different slit functions on a measurement of the sun light to be calculated. Correcting for both slit function and wavelength specification improves the comparison between instruments, especially in the UV-B. (c) far-field stray light. Radiation from wavelengths outside the region of the slit function must be rigorously excluded. if not, it provides a background measurement which limits the sensitivity of the spectroradiometer. As the solar spectrum changes by three orders of magnitude across the UV-B regions, spectrometers need stray light rejection of the same order. In general the single monochromator and diode array instruments did not have sufficient stray light rejection for measurements at the shorter UV-B wavelengths. (d) cosine response. The fore optics of each spectrometer should have a cosine response but in practice this was often far from perfect. Asymmetry in the cosine response can lead to apparent diurnal asymmetry in the measured irradiances, and different cosine errors can add to discrepancies in response between instruments. Knowing the cosine response of an instrument allows corrections to be made, but these involve assumptions about the spectral distribution of the incident radiation. In conclusion, a group of UV spectrometers has been identified which could act together to form a UV network. Other instruments require some improvement in design or operational procedures, but could achieve the level of performance set by the core group. The experiences of the campaigners have led to a greater understanding of instrument and operational requirements, which will aid newcomers to this area of research and point the way to future improvements in hardware and methodologies. A transportable lamp system has been designed and built to maintain an independent check of calibrations when instruments are isolated at their home sites.

Source : Cordis  

Characterization of aerosol spatial distribution and optical properties over the Indian Ocean from airborne LIDAR and radiometry during INDOEX'99 : Indian Ocean Experiment (INDOEX)
2002
Auteurs : Patrick Chazette, P. Chazette, C. FLAMANT, J.-F. LEON, J. F. Leon, J. PELON, S. K. SATHEESH, M Sicard et Didier TANRE
Masquer le résumé
The three-dimensional structure and the optical properties of the Indian pollution plume has been investigated from airborne LIDAR and radiometric measurements over the Indian Ocean during three consecutive days (7, 8, and 9 March 1999) of the INDOEX'99 intensive field phase. The vertical structure of the plume consisted of two layers: the marine atmospheric boundary layer (MABL) and the so-called land plume aloft. The depth of the land plume was observed to depend on the history of the air masses; shallow plumes were associated with air masses coming from the Gulf of Bengal, while deeper plumes were associated with air masses coming from the Indian subcontinent. The larger aerosol optical depths (AODs) observed with Meteosat-5 over the Arabian Sea were associated with the deeper land plume. A combination of airborne light detection and ranging (LIDAR) measurements and Sun photometer measurements at Kaashidhoo Observatory and in Male were used to determine the column-equivalent backscatter-to-extinction ratio needed to retrieve aerosol extinction coefficient profiles and AOD from LIDAR measurements. Direct aerosol forcing was analyzed using a simple radiative model as well as LIDAR-derived AOD and visible flux measurements. Average values of the vertically integrated single scattering albedo of about 0.85 ± 0.05 and 0.8 ± 0.1 were found to be associated with the shallower and the deeper part of the land plume, respectively.
Keywords :
Meteosat satellites ; Air pollution ; Arabian Sea ; Indian Ocean ; Aircraft observation ; Radar observation ; Albedo ; Models ; Forcing ; Extinction index ; Optical thickness ; Air mass ; Atmospheric boundary layer ; Marine atmosphere ; Plume ; Three dimensional structure ; Radiometry ; Lidar ; Optical properties ; Spatial distribution ; Aerosols ;
Source : Pascal - INIST  

Estimate of the aerosol properties over the ocean with POLDER
2000
Auteurs : J.-L. Deuzé, M. HERMAN, A. MARCHAND, G. PERRY, Goloub PHILLIPPE, S. SUSANA, S. SUSANA et Didier TANRE
Masquer le résumé
The wide field of view imaging spectroradiometer Polarization and Directionality of the Earth's Reflectance (POLDER) developed by Centre National d'Etudes Spatiales and operated aboard the Japanese heliosynchronous platform Advanced Earth Observation Satellite (ADEOS) from October 30, 1996, to June 30, 1997, provided the first global systematic measurements of the spectral, directional, and polarized characteristics of the solar radiation reflected by the Earth/atmosphere system. These original observational capabilities offer an opportunity to enhance the characterization of several components of the global environment, especially the oceanic and terrestrial vegetal primary production, the aerosol physical and optical properties, and the tridimensional structure and microphysics of clouds. Here we examine the remote sensing of aerosols over the oceans. In a first step the aerosol optical thickness and Ångström exponent are derived from the radiance measurements. In a second step the polarization measurements are used for the retrieval of the aerosol refractive index. The inversion algorithm assumes spherical, nonabsorbing particles with monomodal lognormal size distribution. The adequacy of this modeling is discussed for a representative set of aerosol observations. Successful retrieval is generally achieved in the presence of small aerosols with Ångström exponent larger than ∼1.0. For such particles, polarization may provide information on the particle refractive index. As the Ångström exponent of the particle decreases, the data fitting residual errors increase, especially in polarized light, which prevents the retrieval of the aerosol refractive index. The trends of the discrepancies point out two shortcomings of the aerosol modeling. The theoretical results systematically underestimate the contribution of small polarizing particles in the polarization measurements for side-scattering angles ranging from 80° to 120°. This indicates very probably that aerosol models have to follow bimodal size distribution. On the other hand, the systematic trend of the directional behavior of the upward radiance and the lack of significant rainbow effect in the measurements result probably from nonsphericity of some large aerosols. Confirmation of these points requires improved analysis of the POLDER data.
Keywords :
Aerosols ; Space remote sensing ; Marine atmosphere ; Spectroradiometry ; Optical thickness ; Refraction index ; Algorithm ; Stokes parameter ; Polarization ;
Source : Pascal - INIST  

Modeling of light scattering in cirrus clouds with inhomogeneous hexagonal monocrystals. Comparison with in-situ and ADEOS-POLDER measurements
2000
Auteurs : Jean-Claude BURIEZ, Laurent C.-LABONNOTE, H. CHEPFER, Hélène Chepfer, Marie DOUTRIAUX-BOUCHER, J.-F. GAYET et B. GERARD
Masquer le résumé
An Inhhomogeneous Hexagonal Monocrystal (IHM) model is used to simulate light scattering by randomly oriented hexagonal ice crystals containing air bubbles. This model based on a combination of ray-tracing, Mie theory and Monte-Carlo techniques, allows to retrieve the scattering phase function. In-situ measurements of the light scattering diagram in natural cirrus clouds with an airborne nephelometer have been performed. The results given by the IHM model have been favorably adjusted with these measurements. This agreement provides an opportunity to use this model in order to analyze ADEOS-POLDER reflectance measurements over cirrus clouds. POLDER uses an original concept to measure, for a given scene, total and polarized reflectances under several viewing directions. A first analysis of cirrus cloud spherical albedoes for the 10th November 1996 shows a rather good agreement between measurements and calculations.
Keywords :
Cloud physics ; Ice cloud ; Light scattering ; Ice crystals ; Hexagonal crystals ; Single crystal ; Cirrus ; Numerical simulation ; Air bubble ; Ray tracing ; Monte Carlo method ; Mie scattering ; Phase function ; Measurement in situ ; Radiometry ; Aircraft observation ; Nephelometry ; Reflectance ; Albedo ; France ; Europe ;
Source : Pascal - INIST  

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


Aristotle University of Thessaloniki
Aristotle University of Thessaloniki


Swedish Meteorological and Hydrological Institute
Swedish Meteorological and Hydrological Institute


Norut Information Technology LTD.
Norut Information Technology LTD.


Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.V.
Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.V.


Norwegian University of Science and Technology
Norwegian University of Science and Technology


Università Degli Studi di Roma la Sapienza
Università Degli Studi di Roma la Sapienza


University of Manchester Institute of Science and Technology
University of Manchester Institute of Science and Technology


Natural Environment Research Council
Natural Environment Research Council


National Institute of Public Health and Environment
National Institute of Public Health and Environment


Finnish Meteorological Institute
Finnish Meteorological Institute


Leopold-franzens-universitaet Innsbruck
Leopold-franzens-universitaet Innsbruck


Universitaet Fuer Bodenkultur Wien
Universitaet Fuer Bodenkultur Wien


Instituto Nacional de Meteorología
Instituto Nacional de Meteorología


Karl-franzens-universitaet Graz
Karl-franzens-universitaet Graz


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  

Comparisons of LASE, aircraft, and satellite measurements of aerosol optical properties and water vapor during TARFOX : Tropospheric aerosol radiative forcing observational experiment (TARFOX), Part 2
2000
Auteurs : V. BRACKETT, V. BRACKETT, Edward V. BROWELL, M. CLAYTON, M Clayton, Richard A. FERRARE, S. HARTLEY, P. HIGNETT, P. V. HOBBS, Syed ISMAIL, S. KOOI, S. Kooi, John Livingston, Philip B. RUSSELL, Didier TANRE et J. P. VEEFKIND
Masquer le résumé
We examine aerosol extinction and optical thickness from the Lidar Atmospheric Sensing Experiment (LASE), the in situ nephelometer and absorption photometer on the University of Washington C-131A aircraft, and the NASA Ames Airborne Tracking Sun Photometer (AATS-6) on the C-131A measured during the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) over the east coast of the United States in July 1996. On July 17 and 24 the LASE profiles of aerosol extinction and aerosol optical thickness (AOT) had a bias difference of 0.0055 km-1 (10%) and a root-mean-square difference of 0.026 km-1 (42%) when compared to corresponding profiles derived from the airborne in situ data when the nephelometer measurements are adjusted to ambient relative humidities. Larger differences for two other days were associated with much smaller aerosol optical thicknesses (July 20) and differences in the locations sampled by the two aircraft (July 26). LASE profiles of AOT are about 10% higher than those derived from the airborne Sun photometer, which in turn are about 10-15% higher than those derived from the airborne in situ measurements. These differences are generally within the error estimates of the various measurements. The LASE measurements of AOT generally agree with AOT derived from both the Along-Track and Scanning Radiometer 2 (ATSR 2) sensor flown on the European Remote Sensing Satellite 2 (ERS-2) and from the Moderate-Resolution Imaging Spectroradiometer (MODIS) airborne simulator (MAS) which flew with LASE on the NASA ER-2 aircraft. Effective particle sizes derived from the MAS data indicate that the LASE retrievals of AOT are valid for effective particle radii less than 0.4 μm. Variations in the relative humidity derived from the LASE water vapor measurements on July 26 are found to be highly correlated with variations in the effective particle size derived from the MAS.
Keywords :
Aerosols ; Vapor ; Water ; Optical properties ; Aircraft observation ; Satellite observation ; Optical thickness ; Optical extinction ; Comparative study ; Altitudinal distribution ; United States ; North America ; America ;
Source : Pascal - INIST  

Spectral reflectance of oceanic whitecaps in the visible and near infrared: Aircraft measurements over open ocean
2001
Auteurs : Pierre-Yves Deschamps, Robert J. FROUIN et Jean-Marc Nicolas
Masquer le résumé
The spectral reflectance of oceanic whitecaps in the visible and near infrared was derived from aircraft push-broom radiometer observations over the open ocean near Toulon, France. Inter-band calibration corrections were performed using spectrally white sun glint reflectance. Whitecap reflectance was found to decrease substantially with wavelength in the near infrared, in agreement with other findings in the coastal zone and the open ocean. The study supports previous conclusions regarding the consequences of neglecting the spectral dependence of whitecap reflectance in ocean color algorithms.
Keywords :
Atlantic Ocean ; Europe ; East Atlantic ; North Atlantic ; France ; Infrared spectrum ; Visible spectrum ; Foam(sea surface) ; Atmospheric correction ; Coastal zone ; Calibration ; Image analysis ; Radiometry ; Aircraft observation ; Reflectance ;
Source : Pascal - INIST  





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