Simulating Meteosat-7 broadband radiances using two visible channels of Meteosat-8

International audienceThis paper addresses the conversion of narrow-to-broadband radiances in the special case of the sensor SEVIRI onboard the satellite Meteosat-8 of the Meteosat Second Generation (MSG). The advent of this new program poses the problem of the transfer of operational procedures from the previous satellite Meteosat-7 to MSG. Among these operational procedures are several different implementations of the Heliosat method to convert Meteosat data into irradiance maps. An easy-to-implement fast-running method is proposed that combines the radiances of the two narrow visible bands of SEVIRI to produce broadband radiances that are almost identical to those observed in the broadband channel of Meteosat-7. A comparison between Meteosat-7 actual radiances and these simulated-radiances shows errors with a negligible bias and a relative root mean square error (RMSE) of 6%. After combination with the uncertainties found in the calibration procedures (10-13%), the total relative RMSE on the radiances amounts to 12-14%. It is concluded that the Meteosat-8 images may be used in operational procedures currently applied to Meteosat-7 images

Description of the software Heliosat-2 for the conversion of images acquired by Meteosat satellites in the visible band into maps of solar radiation available at ground level

This document describes the software Heliosat-II developed by the Groupe Télédétection & Modélisation, Centre d'Energétique, a joint research unit of Armines and Ecole des Mines de Paris. The method Heliosat-II was developed by this research group in 2000-2001, partly with the support of the European Commission (project SoDa, contract DG "INFSO" IST-1999-12245, http://www.sodais. com). This method converts images acquired by the satellite Meteosat into maps of global irradiation received at ground level. Under concern are the images acquired in the visible band of the Meteosat sensor. The software was developed in C for a Unix station. The present document describes the various libraries and procedures. It describes how these can be implemented for the correct execution of the whole method. The procedures described here comprise I/O orders that are to be tailored to the specific format for Meteosat images. The method can be applied to other geostationary satellites offering similar broadband in the visible range (0.4 - 1.1 mm). The input images are geometrically superimposable images. Calibration coefficients exist that convert digital counts into radiances (W m-2 sr-1)

Oil spills: A large scale monitoring from Landsat

International audienceOil pollution at sea using the Landsat multispectral scanner channel was detected. The variations of the reflection coefficient between rough sea and the oil spill was measured. The oil spill flattens the sea and reflects in only one direction while the capillary waves of rough sea scatter the light: a fraction of the incident light only reaches the satellite. An underestimate of pollution is expected during winter because of low solar elevation angles. This method is used to inventory pollution by hydrocarbons in the Mediterranean Sea. An estimation from 800 images shows the cumulative area covered by hydrocarbons, spread over the Mediterranean Sea each year, as 175 000 sq km

The European Solar Radiation Atlas: a valuable digital tool

International audienceThe 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

Study of effective distances for interpolation schemes in meteorology

International audienceThis work explores the possibility of integrating the geographical elements such as orography and presence of water bodies as well as the latitudinal effects into an effective distance when interpolating meteorological fields. This effective distance may then be used in any interpolation methods instead of the standard geodetic distance. Several hundreds of sites are used in Europe to assess the benefits of several effective distances. The meteorological parameters under concern are ten-years averages of monthly means of daily sum of horizontal global irradiation, daily sum of sunshine duration, daily extremes of air temperature, atmospheric pressure and water vapor pressure, and of monthly sums of precipitation. This work demonstrates that taking into account the latitudinal effects in the distance increases the accuracy in interpolation. Such effects have been seldom mentioned in previous publications. The orographic effects may be partly corrected by adding the weighted difference in elevation to the geodetic distance. The proposed effective distance between the point P and each of the measuring sites Xi for all parameters, is found to give better results than the others

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

International audienceInformation 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 programme 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, 10000 requests were satisfied, in 2004, 17000 requests and 27000 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

Three years of experience with the SoDa Web service delivering solar radiation information : lessons learned and perspectives.

Information on solar radiation is a critical issue in several environmental domains as well as for sun-powered sys-tems. The present means for accessing information by users present several severe drawbacks. Three major problems were identified and should be solved to supply users with relevant information: improved access to information, improved space and time description / knowledge of the radiation field and related quantities, improved matching to actual user needs. The SoDa project was launched (2000-2003, IST programme of the European Commission) to bring solutions by an efficient use of advanced information and communication technologies. An integration of information sources of different natures was initiated by the SoDa Intelligent System (see online at http://www.soda-is.com). These sources include databases containing solar radiation parameters and other relevant information; several of them originate from the processing of images taken by satellites. The sources! also include user-oriented applications. The successive prototypes of the SoDa Service were validated through users trials. The outcomes of the project SoDa represent a significant step forward beyond the current state of the art and include substantial original work. The main innovations of SoDa are to offer a smart access to diverse networked sources of information that are geographically dispersed, and to supply users with information of high quality. Surveys of users demonstrated that large gains in terms of efficiency, costs, etc. were expected by engineers, companies, agencies and research institutes if relevant information were more easily available for virtually any geographical location at any time. Accordingly, it was decided in 2003 to create the SoDa Service and to operate it. During these past three years, the SoDa Service underwent several improvements, all aiming at consolidating it with respect to access by users. Improvements were made on the SoDa Intellig! ent System, including works on the user interface and on the p! resentation of the services. Promotion efforts were made towards media, including TV. The effective use of the SoDa Service is increasing from year to year. In 2003, 2000 requests for information were satisfied; in 2004, 20 000 requests; 35 000 are expected in 2005. This communication presents the lessons learned from the past 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 developing a B2B merchant site

Developing a database using Meteosat data for the delivery of solar radiation assessments at ground level

International audienceAn information system, called HelioClim, is offered for answering the needs for long-term time-series of solar radiation data. These data originate from the processing of spaceborne observations made in the visible range by geostationary satellites to derive solar radiation available at ground level. The recent method Heliosat 2 is used. It offers several improvements in operation and accuracy with respect to previous methods. Typical bias for irradiance for a month is 3 W m(-2). A database is being produced, covering the Eastern Atlantic Ocean, Europe and Africa from 1985 onwards and for each day. This database is accessible through the SoDa service on a free basis (http://www.soda-is.com)

Le timbre-poste « Figure parlante »

Alors que je ne marchais pas encore, en appui sur les trois points que sont mes genoux et mon coude gauche je libérais ma main droite pour tracer des lignes sur le sol pendant des heures entières. Ensuite, vint l’expérience des papiers, des crayons, des pinceaux et de la couleur avec ma première petite amie d’école bien plus expérimentée en peinture. Mais c’est à l’âge de sept ans que se produira le premier choc de mon existence, qui déterminera ma vocation : la vision dans la vitrine d’un li..

Integration of Helioclim-1 database into PV-GIS to estimate solar electricity potential in Africa

pages 2989-2992We present a method for computing high resolution database of global horizontal irradiation for Africa and the Mediterranean Basin. Following this, we analyse the geographical and time variability of the solar energy potential for electricity applications. The primary solar radiation data were previously computed from Meteosat satellite images by the Heliosat-2 method and stored in the HelioClim-1 database. From this database, the long term monthly and yearly averages of global irradiation on horizontal plane (period 1985-2004) were derived. Using the PV-GIS method, based on a clear-sky model, interpolation of the clear-sky index and terrain shadowing, the original spatial resolution of HelioClim-1 database (15') was enhanced to 2 km. Using daily global irradiation from the enhanced PV-GIS database we estimated the electricity generation from a typical solar home system. Assuming a 100 Wp installation with a battery and battery charger, together with a performance ratio of 0.75, the power production ranges from about 0.3 to 0.6 kWh per day in most locations in Africa