Assessment of the method used to construct clearness index maps for the new european solar radiation atlas (ESRA).

International audienceWe present an assessement of the methods used to construct maps for a new Solar Radiation Atlas for Europe. For this atlas station data and satellite derived data are used in an interpolation/merging process to derive maps of the long term monthly global radiation that cover an area ranging from 30° W to 70° E and from 25° to 75° N. Our focus is on the discussion of the accuracy of the method applied - a co-kriging technique. Special emphasis is put on the discussion whether the use of satellite derived radiation maps with a low spatial resolution brings benefits

The Tropospheric Distribution and Budget of Ethane

From about 1500 measurements of ethane in the remote troposphere the longitudinally and vertically averaged latitudinal and seasonal variability of ethane was derived. To improve the data coverage, several data sets from literature were included. There are only very few data sets available for the southern hemisphere. Nevertheless, the uncertainty of the average seasonal/latitudinal ethane profile is estimated to less than 30%. The global annually averaged ethane mixing ratio is 860 ppt. There is a strong interhemispheric gradient with an average north/south ratio of 3.5. Within the northern hemisphere there is an average gradient from the highest annual mean value of 2500 ppt around 65°N to about 600 ppt at the equator. In the southern hemisphere there is only a small gradient at low latitudes and at middle and high southern latitudes no significant gradient can be seen. In both hemispheres a significant seasonal cycle with highest mixing ratios in late winter is observed. The ethane source strength needed to balance the atmospheric budget of ethane is estimated to 15.5 Tg/yr, with most of the emissions in the northern hemisphere. An independent estimate of the sources indicate that most of the emissions are due to natural gas losses (6 Tg/yr) and biomass burning (6.4 Tg/yr). This is also compatible with the latitudinal and seasonal variation of the atmospheric ethane removal rates. However, these estimates have substantial uncertainties and it should be noted that the role of the biosphere for the atmospheric budget of ethane is presently not understood

Messung und Modellierung der spektralen Sonnenstrahlung Schlussbericht

Small band measurements of spectral solar radiation by means of commercially available spectral radiometers - which are generally designed for laboratory work - require thorough aptitude tests and mostly special fitting measures. For the already available DM 150, first of all an entrance optics to correct cosine errors, a thermostatted weathercasing, as well as a special control lamp device for field use were developped. An international IEA-field intercomparison of 12 spectral radiometers in the Oberpfaffenhofen area of DLR showed deviations between the global radiation spectra of #+-#15% and #+-#40% for the best and the worst case, resp. The latter was caused by the operational requirements in the field and the mechanical instabilities of some radiometers (including the DM 150). Generally a remarkable portion of the deviations belongs to calibration uncertainties and imperfect cosine corrections. With regard to the summarized experience only principal recommendations on the use of spectral radiometers are given. Measured data of atmospheric heat radiation A and other meteorological data of 16 IEA stations were compiled in a data base at MOH to facilitate the fast uniform validation of 30 formulae for parametrization of A. For the case of sky clouded in 3 layers a parametrization formula was improved and successfully validated. A special reliable A-formula could be developped from the sufficiently high number of data of station Schleswig for the case of low cloudiness only. (orig.)Available from TIB Hannover: F96B618+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Observations and modelling of the global distribution and long-term trend of atmospheric 14CO2

Global high-precision atmospheric Δ14CO2 records covering the last two decades are presented, and evaluated in terms of changing (radio)carbon sources and sinks, using the coarse-grid carbon cycle model GRACE. Dedicated simulations of global trends and interhemispheric differences with respect to atmospheric CO2 as well as δ13CO2 and Δ14CO2, are shown to be in good agreement with the available observations (1940–2008). While until the 1990s the decreasing trend of Δ14CO2 was governed by equilibration of the atmospheric bomb 14C perturbation with the oceans and terrestrial biosphere, the largest perturbation today are emissions of 14C-free fossil fuel CO2. This source presently depletes global atmospheric Δ14CO2 by 12–14‰ yr−1, which is partially compensated by 14CO2 release from the biosphere, industrial 14C emissions and natural 14C production. Fossil fuel emissions also drive the changing north–south gradient, showing lower Δ14C in the northern hemisphere only since 2002. The fossil fuel-induced north–south (and also troposphere–stratosphere) Δ14CO2 gradient today also drives the tropospheric Δ14CO2 seasonality through variations of air mass exchange between these atmospheric compartments. Neither the observed temporal trend nor the Δ14CO2 north–south gradient may constrain global fossil fuel CO2 emissions to better than 25%, due to large uncertainties in other components of the (radio)carbon cycle

Bestimmung verdichteter Flaechenverteilungen der Globalstrahlung aus Messnetzdaten und Erhoehung der Messgenauigkeit von solarer und terrestrischer Strahlung Schlussbericht

Based on global solar radiation data from the radiometric network of Deutscher Wetterdienst and from measurements of the European meteorological satellite METEOSAT, several statistical methods were applied to the topographic and climatic conditions in the Federal Republik of Germany in order to compute and plot dense spatial distributions of global solar radiation on the regional scale. Best results were obtained by using the so-called Kriging method. The measuring accuracy of global solar radiation is increased when direct and diffuse solar radiation are measured separately. For this purpose, a so-called global solar radiation reference radiometer consisting of an absolute pyrheliometer and a pyranometer with shadow-disk on the same solar tracker was developed; for solar elevation angles above 40 and little cloudiness, #+-# 1% measuring accuracy was attained. - By test series it was demonstrated that pyranometers of types PSP and CM11 do not show aging. However, for PSP pyranometers the cosine error function is to be determined by lamps adjusted to the solar spectrum; for CM11 pyranometers, the temperature function of the responsivity is to be measured. - The measuring accuracy of atmospheric thermal radiation at simultaneous high global solar radiation is around #+-# 10%. The large scattering of given calibration and correction values was found to be the main error source. The measuring accuracy is substantially improved by ventilating the pyrgeometer and screening the direct solar radiation by a sun-tracking shadow disk. (orig.)Ausgehend von Globalstrahlungsdaten aus dem Strahlungsmessnetz des Deutschen Wetterdienstes und aus Messungen des europaeischen meteorologischen Satelliten METEOSAT wurden mehrere statistische Verfahren auf die topographischen und klimatischen Bedingungen in der Bundesrepublik Deutschland angewandt, um verdichtete Flaechenverteilungen der Globalstrahlung im regionalen Massstab zu berechnen und kartographisch darzustellen. Dabei lieferte die sog. Kriging-Methode die besten Ergebnisse. Die Messgenauigkeit der Globalstrahlung wird erhoeht, wenn direkte und diffuse Sonnenstrahlung getrennt gemessen werden. Dazu wurde ein sog. Globalstrahlungs-Referenzradiometer als Kombination von Absolut-Pyrheliometer und Pyranometer mit Schattenscheibe auf derselben Sonnennachfuehrung entwickelt, das bei Sonnenhoehenwinkeln ueber 40 und geringer Bewoelkung eine Messgenauigkeit von #+-# 1% erreicht. - Durch Testreihen wurde nachgewiesen, dass Pyranometer vom Typ PSP und CM11 keine Alterung erleiden. Bei PSP-Pyranometern ist jedoch mit sonnenaehnlichen Pruefstrahlern die Cosinusfehler-Funktion, bei CM11-Pyranometern die Temperatur-Funktion der Messempfindlichkeit zu bestimmen. - Die Messgenauigkeit der atmosphaerischen Waermestrahlung betraegt bei gleichzeitiger hoher Globalstrahlung rund #+-# 10%. Als Hauptfehlerquelle wurde die grosse Streuung der angegebenen Kalibrier- und Korrekturwerte festgestellt. Die Messgenauigkeit laesst sich erheblich verbessern, wenn das Pyrgeometer ventiliert sowie mit einer sonnennachgefuehrten Schattenscheibe von der direkten Sonnenstrahlung abgeschirmt wird. (orig.)SIGLEAvailable from TIB Hannover: F94B0633+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

ESRA. Chap 2. Database

308 pagesThis atlas offers a unique instrument dedicated to the knowledge and exploitation of the solar resources for Europe in a broad sense, from Ural to Azores and from Northern Africa to Polar Circle. It is a powerful tool for architects, engineers, meteorologists, agronomists, local authorities, tourism professionals, as well as researchers and students. It covers the period 1981-1990. It offers fundamental knowledge on the solar radiation available at groundlevel, which is of primary importance for both the life and the climate (including the ocean) since it is the primary source of energy on Earth by far. This book describes the course of the Sun across the sky as it varieties throughout the year and with the geographical location. The interactions of the solar radiation with the atmosphere and its components (haze, turbidity, clouds, etc.), and the separation of the radiation into the direct and diffuse parts are discussed. The importance of the solar radiation in various domains is presented, with an emphasis on solar engineering, where solar energy is used to provide electricity in photovoltaics systems, to supply hot water or heat houses. Ground radiation measurement techniques and instruments are described. Satellite images are also used. They are combined with ground measurements to provide a synoptic view of the distribution of the solar radiation over Europe. The structure of the database and its main applications are described. 26 coloured maps (ten years average 1981-90) describe the solar radiation and its direct and diffuse parts. They also detail the changes with time. The value of the atlas can be usefully extended by using it in conjunction with the complementary volume and CD-ROM called: The European Solar Radiation Atlas - vol. 2: database and exploitation software, also published by Les Presses de l'Ecole des Mines. The database offers spatial (every 10 km approximately) and temporal knowledge for different timescales (front climatological means -more than 700 stations- to hourly values -7 stations-) on the solar resources: irradiation (global and its components), sunshine duration, as well as air temperatures, precipitation, water vapour pressure, air pressure in a number of stations. The software uses the database in either a "map" or a "station" mode at user choice. Once a station been selected, the program looks for all the data available for this station. The software includes algorithms covering the following fields: solar geometry, optical properties of the atmosphere, estimation of hourly slope irradiation under cloudless skies, estimation of solar irradiation values (going from daily to hourly values, conversion from horizontal to titled surfaces), spectral irradiance, illuminance, daily mean profiles of temperature and other statistical quantities (central moments, extremes, probability, cumulative probability and utilizability curves). Graphics can be displayed in 2 or 3 dimensions. Some applications studies on solar engineering can be performed too. This Atlas bas been realised on behalf of the European Commission, by a team led by the company GET (Jülich, Germany), and comprising the Deutsche Wetterdienst (Hamburg, Germany), Armines/Ecoles des Mines de Paris et de Nantes (France), Instituto Nacional de Engenharia e Tecnologia Industrial (Lisbon, Portugal), the Technical University of Lyngby (Denmark), the World Radiation Data Centre (Saint-Petersburg, Russia), and Institut Royal de Météorologie (Brussels, Belgium), John Page (Sheffield, United Kingdom) and Robert Dogniaux (Brussels, Belgium) acting as advisors

The European Solar Radiation Atlas Vol.2: Database and exploitation software

CD-ROM with databases and software included; CD-Rom avec bases de données et logiciels inclusInternational audienc