Michel Albuisson

A method for the determination of the global solar radiation from meteorological satellite data

Abstract A statistical method is presented for the determination of the global solar radiation at ground level. It makes use of data from the meteorological satellites, which provide extensive coverage as well as adequante ground resolution. In the first step, a reference map of ground albedo is deduced from the time-sequence of satellite images. Then, by comparing the satellite data with the computed albedo map, a cloud coverage index is determined for each ground point of 5 km × 5 km. This index is linearly correlated to the atmospheric transiission factor. The regression parameters are estimated using a training set provided by ground pyranometers. Tests for two different time periods show a good agreement between the actual and model-derived hourly global radiation.

Converting a successful research project into a sustainable service: The case of the SoDa Web service

Abstract Information on solar radiation is a critical issue in several environmental domains. The means for accessing information suffer from severe drawbacks. The SoDa project was launched (2000–2003, IST program of the European Commission) to bring solutions by an efficient use of information and communication technologies. Integration of information sources of different natures was realized by the SoDa Intelligent System. Surveys of users demonstrated that large gains in terms of efficiency, costs, etc. were expected by engineers, companies, agencies and research institutes. The SoDa Service was created in 2003. During the past three years, it has undergone several improvements, including works on the user interface and on the presentation of the services, all aiming at consolidating it with respect to access by users. Promotion efforts were made in the media, including TV. The use of the SoDa Service is increasing from year to year: in 2003, 10,000 requests were satisfied, in 2004, 17,000 requests and 27,000 in 2005. This article presents the lessons learned from the past years and the perspectives of the SoDa Service. We discuss the sustainability of the SoDa Service, the technologies used and the approach to customers, in the perspective of building a B2B merchant site.

The European Solar Radiation Atlas: a valuable digital tool

The new CD-ROM based European Solar Radiation Atlas (ESRA) is now available. It is published by Les Presses de l’Ecole des Mines de Paris on behalf of the European Commission. This atlas, in 2 volumes, is an instrument dedicated to providing knowledge and aiding exploitation of the solar resources across a wide sweep of Europe, from the Urals to the Azores and from Northern Africa to Polar Circle. It is a powerful tool for architects, engineers, meteorologists, agronomists, local authorities, and tourism professionals, as well as for researchers and students. The input data are based on the period 1981-1990. The first volume provides a broad overview with supporting maps. It starts by describing the course of the Sun across the sky as it varies across the year with geographical location. Then the interactions of the solar radiation with the atmosphere and its components (haze, turbidity, clouds, etc.) and the separation of the solar radiation into the direct and diffuse parts are discussed. The outline structures of the database and the ESRA software package are next described. Sixteen coloured maps provide data on the monthly mean global, beam, diffuse irradiation on horizontal surface and the clearness index for March, June, September and December. The mapped values are averages over the 10-year period 1981-1990. Additionally there are the corresponding four annual maps, also a country-based relief map and a map of ground observing stations used. There are two special maps giving zones of similar irradiation and zones of similar biomass productivity. The second more technical volume comprises a book of 296 pages and a CD-ROM. The book describes the detailed content of the CD-ROM, explaining how it was constructed and how to use the software. The CD-ROM contains a database, which offers spatial (every 10 km approximately) and temporal climatic information for different time scales (from climatological means - more than 700 stations - to hourly values - 7 stations). It includes the solar resources: irradiation (global and its components), sunshine duration, as well as air temperatures, precipitation, water vapour pressure, air pressure for a number of stations. The CD-ROM also contains the software to exploit the database. The software uses either a “map” or a “station” mode at user choice. In the first case, any geographical site can be designated. In the second mode, only the available measuring stations can be selected. The software includes algorithms covering the following fields: solar geometry, optical properties of the atmosphere, estimation of hourly irradiation on slope under cloudless skies, estimation of solar irradiation values (going from daily to hourly values, conversion from horizontal to tilted surfaces), spectral irradiance, illuminance, daily

A Comparison between Infrared Satellite Images and Sea Truth Measurements

A method for processing NOAA-VHRR and TIROS N-VHRR data is outlined. Noise elimination is performed and sea surface temperature maps are produced with a maximum temperature resolution of 0.5°C. A comparison is shown between in situ temperature measurements and VHRR radiometric temperatures along a track intersecting the cyclonic gyre of the Liguro-Provencal basin. The ecologic significance of the observed thermal fronts is demonstrated by stations showing the vertical variations of oceanographic parameters. The satellite image allows apprehension of the two dimensional geometry of these fronts. This information can be used in the evaluation of the primary production of the basin. It is also emphasized that the systematic processing of I.R. images brings a significant contribution to the planning of future oceanographic cruises.