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
Particles of human origin extinguishing natural solar irradiance in climate systems
PHOENICS
2002 - 2005

Sujets :
Meteorology, Resources of the Sea, Fisheries, Environmental Protection, Forecasting
Participants :
Laboratoire d'Optique Atmosphèrique
Laboratoire d'Optique Atmosphèrique


Laboratoire des Sciences du Climat et de l'Environnement
Laboratoire des Sciences du Climat et de l'Environnement


Institute for Chemistry (otto Hahn Institute)
Institute for Chemistry (otto Hahn Institute)


Institute for Meteorology
Institute for Meteorology


UNIVERSITY OF CRETE HELLAS
UNIVERSITY OF CRETE
Education,Other

DEPARTMENT OF CHEMISTRY - SCHOOL OF SCIENCES ENVIRONMENTAL CHEMICAL PROCESSES LABORATORY Leoforos Knosou, Ampelokipi 71409
HELLAS
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
UTRECHT UNIVERSITY NEDERLAND
UTRECHT UNIVERSITY
Other,Education

PO Box 80.125 8,HEIDELBERGLAAN 8 3508 TC
NEDERLAND
COMMISSION OF THE EUROPEAN COMMUNITIES ITALIA
COMMISSION OF THE EUROPEAN COMMUNITIES
Research

INSTITUTE FOR ENVIRONMENT AND SUSTAINABILITY ATMOSPHERIC PROCESSES IN GLOBAL CHANGE UNIT Via Enrico Fermi TP 290 21020
ITALIA
NATIONAL RESEARCH COUNCIL OF ITALY ITALIA
NATIONAL RESEARCH COUNCIL OF ITALY
Research,Other

ISTITUTO DI SCIENZE DELL'ATMOSFERA E DEL CLIMA Via P. Gobetti 101 40129
ITALIA
Hide objectives
PHOENICS is a global modelling project to study the direct climate effect of multi-component mixed troposphere aerosols. The potentially great climatic importance of aerosols urgently requires improvement of the estimates of the climate effect of aerosols and better evaluation of the associated uncertainties. Innovative size-resolved simulations of the distribution and properties of the mixture of all major aerosol components will be performed with a global 3-dimensional atmospheric general circulation model to assess the direct effect of aerosols. Several of the main uncertainties associated with this effect will be quantified and reduced by model improvement, comparison to selected observations and optimal use of satellite data. The impact of European emissions on the European and global environment and climate, and the influence of other world regions on Europe will be assessed focusing on the role of the Mediterranean.

Source : Cordis  

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  

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  

Aerosol detection by TOMS and POLDER over oceanic regions
2000
Auteurs : Isabelle Chiapello, J. HERMAN, A. MARCHAND, Goloub PHILLIPPE, Didier TANRE et O. TORRES
Masquer le résumé
In this paper we investigate the aerosol content retrieved by Earth-Probe Total Ozone Mapping Spectrometer (TOMS) and ADEOS POLDER over oceanic regions for the period November 1996 to June 1997. We combine the aerosol index (AI) derived from TOMS corresponding to UV-absorbing aerosols (desert dust and biomass-burning particles) and the POLDER aerosol optical thickness (AOT) and Angström coefficients. The seasonal composited images from the two sensors show in general consistent spatial distributions of the aerosol over oceans, with the highest aerosol content retrieved over the north tropical and equatorial Atlantic. Over the different oceanic regions investigated (i.e., Atlantic Ocean, Mediterranean Sea, Indian Ocean, and Pacific Ocean), TOMS and POLDER show a good correspondence in the aerosol seasonal variability. At all sites with the exception of the region of the Sea of Japan, we show that during the time periods of maximum aerosol amounts, a linear correlation exists between the TOMS AI and POLDER AOT. For the Sea of Japan the influence of different aerosol types (i.e., desert dust and sulfates) is likely to complicate the TOMS detection. For the other oceanic regions, our results suggest a large variability in the relationship between the TOMS AI and the POLDER AOT, which is likely to be related to changes in aerosol composition and/or altitude.
Keywords :
Aerosols ; Marine atmosphere ; World ocean ; Satellite observation ; Planetary distribution ; Comparative study ;
Source : Pascal - INIST  

Radiative and microphysical interactions between marine stratocumulus clouds and Saharan dust. 1. Remote sensing observations
2002
Auteurs : Guy Cautenet, I. JANKOWIAK et F. PRADELLE
Masquer le résumé
This work emphasizes the radiative impact of Saharan dust particles in the presence of clouds, over the tropical North Atlantic Ocean. A first analysis based upon recent European Centre for Medium-Range Weather Forecasts data confirms the classical observations; that is, in summer, the dust plume lies over the trade wind inversion, that is to say, over the main cloud layer. In winter, however, dust particles generally are transported in the trade wind layer, namely, where the major part of clouds is developing. In a second part, we present a statistical analysis based upon a 6-year series of daily VIS and IR Meteosat data. Our study reveals, at any season, a decrease in the apparent cloud reflectivity derived from satellite measurements. Minimum values of this albedo are found in geographical areas where dust particles are most often observed and where they have their highest values in optical thickness. This albedo decrease can exceed 20% during spring months, when the dust outbreaks are the most frequent. A final discussion puts forward some physical processes that may explain the observations. In summer, dust presence may result in a change of the reflectance of the system, due to an increase of the absorption of the surface-cloud-dust plume system. On the other hand, during the winter season, the cloud albedo decrease may be in part explained by the drying of the atmosphere due to the dry air masses associated with the dust outbreaks coming from the Saharan desert. However, an interesting and complementary explanation is put forward for the winter case: Because of its lower altitude, the dust plume is likely to mix with cloud water. Consequently, in-cloud processes may lead to a change in droplet spectrum size, which in turn, could affect the cloud reflectivity and therefore the reflectance measured at the top of the atmosphere. Therefore, whatever the physical processes involved, the dust outbreaks seem always to lead to a decrease in the cloud cover albedo over the tropical North Atlantic Ocean. In part 2 of this study, the observations will be completed by numerical modeling dealing with radiation, microphysics, and mesoscale transport, in order to better explain and understand this radiative effect.
Keywords :
Atlantic Ocean ; Africa ; Equatorial Atlantic ; Size ; Dimension spectrum ; North Atlantic ; Radiative properties ; Sahara ; Atmospheric dust ; Marine atmosphere ; Droplet ; Desert ; Air mass ; Dry air ; Reflectance ; Optical thickness ; Albedo ; Satellite observation ; Reflectivity ; Statistical analysis ; Particle transport ; Trade wind ; Seasonal variation ; Space remote sensing ; Water cloud ; Stratocumulus cloud ;
Source : Pascal - INIST  

Comments on the "Spatial variability of coastal surface water temperature during upwelling"
1980
Auteurs : Pierre-Yves Deschamps, Robert Frouin et Lucien Wald
Masquer le résumé
Comments on the article "Spatial variability of coastal surface water temperature during upwelling"
Keywords :
Source : HAL  

Second European Stratospheric Arctic and Midlatitude Experiment campaign : Correlative measurements of aerosol in the northern polar atmosphere
1997
Auteurs : Richard M. BEVILACQUA, Colette Brogniez, K. H. FRICKE, K. H. Fricke, M.D. Fromm, Karl W. HOPPEL, J. S. HORNSTEIN, S. S. KRIGMAN, Jacqueline LENOBLE, J. LUMPE, R. RAMANANAHERISOA, Eric P. SHETTLE et Christos S. ZEREFOS
Masquer le résumé
The stratospheric aerosol layer in the Arctic winter was studied by three independent, height-resolving, optical techniques close in space and time on February 2, 1994, above northern Scandinavia. The balloon-borne Radiomètre Ballon (RADIBAL) experiment measured altitude profiles of the radiance and polarization of scattered sunlight at two wavelengths: a ground-based lidar measured vertical backscatter ratio profiles at one wavelength and the satellite-borne Polar Ozone and Aerosol Measurement (POAM) II solar occultation instrument measured atmospheric extinction at nine wavelengths. From the RADIBAL data the mode radius and variance of the aerosol size distribution are derived as well as the particle refractive index. This size distribution is used to convert the lidar backscatter ratio to an extinction coefficient. The POAM 11 aerosol extinction coefficients are derived under the assumption that the spectral dependence of the aerosol optical depth follows a quadratic law at all altitudes. This quadratic dependence is used to deduce the mode radius and variance of the aerosol size distribution and to interpolate the POAM data to the wavelengths of the other two instruments. In the common altitude range of measurements, from 15 to 23 km, the derived aerosol extinction profiles agree within the instrument measurement errors and the temporal and spatial variability of the aerosol layer. The geographic area of measurements was outside the polar vortex on that day. The effective aerosol particle radius decreases slightly with increasing altitude from 0.40 μm at 16 km to 0.25 μm at 22 km and the effective variance ranges from 0.15 to 0.25. The mean refractive index is 1.44 at 850 nm, which is compatible with a 75%-sulfuric acid-water aerosol. The aerosol number densities decrease from 5 to 1 cm-3 over the 16- to 22-km altitude range and the surface area density decreases from 5 to less than 1 μm2 cm-3 over the same altitude range.
Keywords :
Stratosphere ; Stratospheric aerosol ; Winter ; Vertical profile ; Optical thickness ; Extinction index ; Particle size ; Dimension spectrum ; Balloon observation ; Ground based measurement ; Radar observation ; Satellite observation ; Arctic Region ; Scandinavia ; Europe ;
Source : Pascal - INIST  





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