Sample records for extraterrestrial solar irradiance

  1. Extraterrestrial Solar Neutrino Physics

    E-print Network

    W-Y. Pauchy Hwang; Jen-Chieh Peng

    2011-07-26

    We advocate the extraterrestrial solar neutrino physics (etSNP) as a means of investigating solar neutrino physics (SNP). As we already know, the dominant and subdominant (vacuum) oscillation lengths would be approximately one kilometer and one hundred kilometers. On the other hand, we know so far that the matter-enhanced oscillations take place only in the core of the Sun. Thus, the etSNP, i.e. solar neutrino physics that could be extracted outside the Earth, would assume a special unique role. The etSNP experiments include (1) a satellite (detector) around the Earth or around the Jupiter or others (to provide the shadow, for the matter-enhanced neutrino oscillations), (2) during the Sun-Venus-Earth eclipse or similar, and (3) the chemical compositions of the geology type (as in the Jupiter or in the Venus, to study the origins of these planets). To be specific, we note that the reactions induced by the ^8B solar neutrinos, in view of the sole high energy nature (E_\

  2. Calibration of EOS multispectral imaging sensors and solar irradiance variability

    NASA Technical Reports Server (NTRS)

    Mecherikunnel, Ann

    1991-01-01

    Earth Observation System (EOS) optical multispectral imaging sensors provide images of the earth at various spectral and spatial resolutions, in the visible (VIS) and infrared (IR) regions of the solar spectrum. Accurate knowledge of extraterrestrial solar spectral irradiance and its variations with time, are needed to trace sensor calibration in space, and for the development of terrestrial atmospheric models needed in data validation. A brief review of the extraterrestrial solar VIS/IR spectral irradiance available in the literature will be reviewed, and the need to develop an extraterrestrial solar spectral irradiance for the EOS studies will be pointed out. The solar calibration of the Earth Radiation Budget Experiments (ERBE), earth-viewing sensors will be discussed. Observed variations in the solar constant (solar irradiance, at the mean sun-earth distance of one astronomical unit, integrated over all wavelengths), and solar spectral irradiance with solar activity and its implications for EOS studies also will be discussed.

  3. Extraterrestrial applications of solar optics for interior illumination

    NASA Technical Reports Server (NTRS)

    Eijadi, David A.; Williams, Kyle D.

    1992-01-01

    Solar optics is a terrestrial technology that has potential extraterrestrial applications. Active solar optics (ASO) and passive solar optics (PSO) are two approaches to the transmission of sunlight to remote interior spaces. Active solar optics is most appropriate for task illumination, while PSO is most appropriate for general illumination. Research into solar optics, motivated by energy conservation, has produced lightweight and low-cost materials, products that have applications to NASA's Controlled Ecological Life Support System (CELSS) program and its lunar base studies. Specifically, prism light guides have great potential in these contexts. Several applications of solar optics to lunar base concepts are illustrated.

  4. Extraterrestrial applications of solar optics for interior illumination

    NASA Astrophysics Data System (ADS)

    Eijadi, David A.; Williams, Kyle D.

    1992-09-01

    Solar optics is a terrestrial technology that has potential extraterrestrial applications. Active solar optics (ASO) and passive solar optics (PSO) are two approaches to the transmission of sunlight to remote interior spaces. Active solar optics is most appropriate for task illumination, while PSO is most appropriate for general illumination. Research into solar optics, motivated by energy conservation, has produced lightweight and low-cost materials, products that have applications to NASA's Controlled Ecological Life Support System (CELSS) program and its lunar base studies. Specifically, prism light guides have great potential in these contexts. Several applications of solar optics to lunar base concepts are illustrated.

  5. Extreme total solar irradiance due to cloud enhancement at sea level of the NE Atlantic coast of Brazil

    Microsoft Academic Search

    Rubén D. Piacentini; Graciela M. Salum; Naum Fraidenraich; Chigueru Tiba

    2011-01-01

    Extraterrestrial total solar irradiance, usually called Solar Constant, is attenuated by the atmosphere in different proportions, depending mainly on solar zenith angle and altitude of the measurement point. In this work, it is presented very high and extreme horizontal plane measurements of global solar irradiance that in some days overpassed the Solar Constant corrected by the actual Sun–Earth distance (CSC).

  6. The total and spectral solar irradiance and its possible variations

    NASA Technical Reports Server (NTRS)

    Thekaekara, M. P.

    1975-01-01

    The present status of knowledge of the total and spectral irradiance of the sun is briefly reviewed. Currently accepted values of the solar constant and the extraterrestrial solar spectral irradiance are presented along with a discussion of how they were derived. Data on the variability of the solar constant are shown to be conflicting and inconclusive. Some of the alleged sun-weather relationships are cited in support of the need of knowing more precisely the variations in total and spectral solar irradiance. An overview of a solar monitoring program is discussed, with special emphasis on the Solar Energy Monitor in Space experiment which was proposed for several spacecraft missions. It is a combination of a solar constant detector and a prism monochromator. The determination of absolute values and the possible variations of the total and spectral solar irradiance, from measurements outside of the atmosphere is discussed.

  7. Mechanistical Studies on the Irradiation of Methanol in Extraterrestrial Ices

    NASA Astrophysics Data System (ADS)

    Bennett, Chris J.; Chen, Shih-Hua; Sun, Bing-Jian; Chang, Agnes H. H.; Kaiser, Ralf I.

    2007-05-01

    Pure ices of amorphous methanol, CH3OH(X1A'), were irradiated at 11 K by 5 keV electrons at 100 nA for 1 hr. These energetic electrons simulate electronic energy transfer processes that occur as interstellar ices, comets, and icy solar system bodies are subjected to irradiation from MeV ions and secondary electrons produced in this process. The results were analyzed quantitatively via absorption-reflection-absorption Fourier transform infrared (FTIR) spectroscopy, with the identification of new species aided by high-level electronic structure calculations. The unimolecular decomposition of methanol was found to proceed via the formation of (1) the hydroxymethyl radical, CH2OH(X2A''), and atomic hydrogen, H(2S1/2), (2) the methoxy radical, CH3O(X2A'), plus atomic hydrogen, (3) formaldehyde, H2CO(X1A1) plus molecular hydrogen, H2(X1?+g), and (4) the formation of methane, CH4(X1A1), together with atomic oxygen, O(1D). The accessibility of the last channel indicates that the reverse process, oxygen addition into methane to form methanol, should also be feasible. A kinetic model is presented for the decomposition of methanol into these species, as well as the formyl radical, HCO(X2A'), and carbon monoxide, CO(X1?+). During the subsequent warming up of the sample, radicals previously generated within the matrix were mobilized and found to recombine to form methyl formate, CH3OCHO(X1A'), glycolaldehyde, CH2OHCHO(X1A'), and ethylene glycol, HOCH 2CH2OH(X1A). Upper limits for the production of these species by the recombination of neighboring radicals produced during irradiation as well as during the warm-up procedure are presented. The generation of these molecules by irradiation of ices in the solid state and their subsequent sublimation into the gas phase can help explain their high abundances as observed toward hot molecular cores and underlines their importance in astrobiology.

  8. The effect of irradiation on the magnetic properties of rock and synthetic samples with implications to irradiation of extraterrestrial materials in space

    NASA Astrophysics Data System (ADS)

    Bezaeva, N. S.; Gattacceca, J.; Rochette, P.; Duprat, J.; Rizza, G.; Vernazza, P.; Trukhin, V. I.

    2013-05-01

    Before reaching the Earth through meteorite falls or sample return, most extraterrestrial materials have been exposed to space radiations at different stages in their history. In the Solar System there are three main types of particle radiation: large fluxes of low-energy solar wind (SW) particles, smaller fluxes of high-energy galactic-cosmic-ray (GCR) particles, and intermittent intense fluxes of solar-flare-associated particles, also called solar cosmic rays or solar energetic particles (SEP). We report here the results of laboratory analog experiments to consider the potential effects of SEP and GCR on the magnetic properties of extraterrestrial materials. We carried out proton bombardment experiments (with irradiation energies E1=400 keV and E2=850 keV and three irradiation fluences in 1014-1016 p/cm2 range) and lead-ion bombardment experiments (E=1 GeV) on (previously demagnetized by 120 mT alternating magnetic field) rock and synthetic samples with the following magnetic carriers: metallic iron and nickel iron, Ti-rich and Ti-free magnetite, pyrrhotite. Irradiation experiments resulted in either further demagnetization or magnetization of irradiated samples depending on the type of magnetic mineralogy and type of ionizing radiation involved. Apart for the formation of radiation-induced remanent magnetization (RIRM), we observed major changes in bulk magnetic properties, i.e., a moderate to dramatic decrease (up to 93%) in the coercivity of remanence Bcr for all iron-bearing phases (iron-in-epoxy and Bensour meteorite samples). Contrary to iron-bearing samples, several magnetite-bearing samples experienced a radiation-induced magnetic hardening (increase in Bcr). Magnetic hardening was also observed for Ar2+ ion-irradiated nickel iron-bearing HED meteorites, measured for comparison with the previously stated results. Therefore, the combined effect of SEP with GCR may magnetically soften iron-bearing materials and harden magnetite-bearing materials. In order to answer the question weather RIRM may account for natural remanent magnetization of meteorites and lunar samples, physical mechanism of RIRM formation and potential dependence of RIRM intensity on the background magnetic field present during irradiation event should be investigated.

  9. Solar Cycle Variation in Solar Irradiance

    NASA Astrophysics Data System (ADS)

    Yeo, K. L.; Krivova, N. A.; Solanki, S. K.

    2014-12-01

    The correlation between solar irradiance and the 11-year solar activity cycle is evident in the body of measurements made from space, which extend over the past four decades. Models relating variation in solar irradiance to photospheric magnetism have made significant progress in explaining most of the apparent trends in these observations. There are, however, persistent discrepancies between different measurements and models in terms of the absolute radiometry, secular variation and the spectral dependence of the solar cycle variability. We present an overview of solar irradiance measurements and models, and discuss the key challenges in reconciling the divergence between the two.

  10. Cosmochemistry: Understanding the Solar System through analysis of extraterrestrial materials

    PubMed Central

    MacPherson, Glenn J.; Thiemens, Mark H.

    2011-01-01

    Cosmochemistry is the chemical analysis of extraterrestrial materials. This term generally is taken to mean laboratory analysis, which is the cosmochemistry gold standard because of the ability for repeated analysis under highly controlled conditions using the most advanced instrumentation unhindered by limitations in power, space, or environment. Over the past 40 y, advances in technology have enabled telescopic and spacecraft instruments to provide important data that significantly complement the laboratory data. In this special edition, recent advances in the state of the art of cosmochemistry are presented, which range from instrumental analysis of meteorites to theoretical–computational and astronomical observations. PMID:22128323

  11. Cosmochemistry: Understanding the Solar System through analysis of extraterrestrial materials.

    PubMed

    MacPherson, Glenn J; Thiemens, Mark H

    2011-11-29

    Cosmochemistry is the chemical analysis of extraterrestrial materials. This term generally is taken to mean laboratory analysis, which is the cosmochemistry gold standard because of the ability for repeated analysis under highly controlled conditions using the most advanced instrumentation unhindered by limitations in power, space, or environment. Over the past 40 y, advances in technology have enabled telescopic and spacecraft instruments to provide important data that significantly complement the laboratory data. In this special edition, recent advances in the state of the art of cosmochemistry are presented, which range from instrumental analysis of meteorites to theoretical-computational and astronomical observations. PMID:22128323

  12. Geiger M., Diabat L., Mnard L., Wald L., 2002. A web service for controlling the quality of measurements of global solar irradiation. Solar Energy, Vol. 73, No 6, pp. 475-480

    E-print Network

    Paris-Sud XI, Université de

    of measurements of global solar irradiation. Solar Energy, Vol. 73, No 6, pp. 475-480 Copyright Ecole des Mines de, Centre d'Energétique, Ecole des Mines de Paris, BP 207, 06904 Sophia Antipolis cedex, France. Tel.: +33 with some expectations based upon the extraterrestrial irradiation and a simulation of the irradiation

  13. The Sensitivity of Chemistry and Composition of the Troposphere on the Incident Solar Flux prescribed at

    E-print Network

    Haak, Hein

    , The Netherlands 1. Introduction The extra-terrestrial solar irradiance incident at the top of the atmosphere (TOA Spectra Figure 1: Comparison of the extra-terrestrial TOA solar fluxes with respect to measured

  14. Modeling monthly mean variation of the solar global irradiation

    NASA Astrophysics Data System (ADS)

    Vindel, J. M.; Polo, J.; Zarzalejo, L. F.

    2015-01-01

    The monthly mean variation of the solar global reaching the Earth's surface has been characterized at a global level by a regression model. This model considers the monthly variation itself (to different horizons and even the maximum annual variation) as the study variable, and it is applied without using data corresponding to measured meteorological variable. Two explicative variables have been used, the variation of the extraterrestrial irradiation and the variation of the clear sky global horizontal irradiation. The work has been carried out from datasets including average global daily solar irradiation for each month of the year measured on the ground. The model quality has been proven to be very dependent of the temporal variation considered, in such a way that higher variations, that is to say, higher distances between months, lead to an improvement in the model outcomes.

  15. Relationship between diffuse, total, and extraterrestrial solar radiation

    Microsoft Academic Search

    S TULLER

    1976-01-01

    A method of approximating diffuse beam solar radiation is extended to the upper middle latitudes through the use of several years of mean monthly data and one year of daily data recorded at four stations in Canada which represent a variety of climatic regions as well as both highly urbanized and remote localities. (WDM)

  16. Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter

    NASA Technical Reports Server (NTRS)

    Reedy, Robert C.

    1999-01-01

    There are two main types of cosmic rays that have sufficient energy to induce nuclear reactions -- the galactic cosmic rays (GCR) and solar cosmic rays (also called solar energetic particles). Both types of particles can have production rates and production ratios in the small objects often found in cold and hot deserts that are different from those seen for most meteorites, which typically have radii of approx. 10-100 centimeters. GCR production rates are often lower than those for most meteorites. GCR production ratios, such as Ne-22/Ne-21, are also often different in small objects. Smaller meteoroids also are more likely to have nuclides made by solar-cosmic-ray (SCR) particles than typically-sized meteorites. The very small meteorite Salem had large amounts of SCR-produced radionuclides. Meteorites recovered in Antarctica are more likely to contain SCR-produced nuclides than other meteorites. Martian and lunar meteorites are also likely to have SCR-produced nuclides. Production rates and profiles for SCR-produced nuclides in meteoroids have been calculated previously. However, the cross sections for the nuclear reactions making many SCR-produced nuclides, such as Be-10 were not well measured then. New rates and profiles are calculated here using good cross sections for the reactions making these nuclides.

  17. Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter

    NASA Technical Reports Server (NTRS)

    Reedy, Robert C.

    2000-01-01

    There are two main types of cosmic rays that have sufficient energy to induce nuclear reactions -- the galactic cosmic rays (GCR) and solar cosmic rays (also called solar energetic particles). Both types of particles can have production rates and production ratios in the small objects often found in cold and hot deserts that are different from those seen for most meteorites, which typically have radii of approx.10-100 centimeters. GCR production rates are often lower than those for most meteorites. GCR production ratios, such as Ne-22/Ne-21, are also often different in small objects. Smaller meteoroids also are more likely to have nuclides made by solar-cosmic-ray (SCR) particles than typically-sized meteorites. The very small meteorite Salem had large amounts of SCR-produced radionuclides. Meteorites recovered in Antarctica are more likely to contain SCR-produced nuclides than other meteorites. Martian and lunar meteorites are also likely to have SCR-produced nuclides. Production rates and profiles for SCR-produced nuclides in meteoroids have been calculated previously. However, the cross sections for the nuclear reactions making many SCR-produced nuclides, such as Be-10, were not well measured then. New rates and profiles are calculated here using good cross sections for the reactions making these nuclides.

  18. The PUR Experiment on the EXPOSE-R facility: biological dosimetry of solar extraterrestrial UV radiation

    NASA Astrophysics Data System (ADS)

    Bérces, A.; Egyeki, M.; Fekete, A.; Horneck, G.; Kovács, G.; Panitz, C.

    2015-01-01

    The aim of our experiment Phage and Uracil Response was to extend the use of bacteriophage T7 and uracil biological dosimeters for measuring the biologically effective ultraviolet (UV) dose in the harsh extraterrestrial radiation conditions. The biological detectors were exposed in vacuum-tightly cases in the European Space Agency (ESA) astrobiological exposure facility attached to the external platform of Zvezda (EXPOSE-R). EXPOSE-R took off to the International Space Station (ISS) in November 2008 and was installed on the External platform of the Russian module Zvezda of the ISS in March 2009. Our goal was to determine the dose-effect relation for the formation of photoproducts (i.e. damage to phage DNA and uracil, respectively). The extraterrestrial solar UV radiation ranges over the whole spectrum from vacuum-UV (?<200 nm) to UVA (315 nmextraterrestrial UV radiation. From this aspect the role of the photoreversion in the extension of the biological UV dosimetry are discussed.

  19. Enantiomeric excesses induced in amino acids by ultraviolet circularly polarized light irradiation of extraterrestrial ice analogs: A possible source of asymmetry for prebiotic chemistry

    SciTech Connect

    Modica, Paola; De Marcellus, Pierre; D'Hendecourt, Louis Le Sergeant [Univ. Paris-Sud, Institut d'Astrophysique Spatiale, UMR 8617, F-91405 Orsay (France); Meinert, Cornelia; Meierhenrich, Uwe J. [Univ. Nice Sophia Antipolis, Institut de Chimie de Nice, UMR 7272 CNRS, F-06108 Nice (France); Nahon, Laurent, E-mail: laurent.nahon@synchrotron-soleil.fr, E-mail: ldh@ias.u-psud.fr [Synchrotron SOLEIL, F-91192 Gif-sur-Yvette (France)

    2014-06-10

    The discovery of meteoritic amino acids with enantiomeric excesses of the L-form (ee {sub L}) has suggested that extraterrestrial organic materials may have contributed to prebiotic chemistry and directed the initial occurrence of the ee {sub L} that further led to homochirality of amino acids on Earth. A proposed mechanism for the origin of ee {sub L} in meteorites involves an asymmetric photochemistry of extraterrestrial ices by UV circularly polarized light (CPL). We have performed the asymmetric synthesis of amino acids on achiral extraterrestrial ice analogs by VUV CPL, investigating the chiral asymmetry transfer at two different evolutionary stages at which the analogs were irradiated (regular ices and/or organic residues) and at two different photon energies (6.6 and 10.2 eV). We identify 16 distinct amino acids and precisely measure the L-enantiomeric excesses using the enantioselective GC × GC-TOFMS technique in five of them: ?-alanine, 2,3-diaminopropionic acid, 2-aminobutyric acid, valine, and norvaline, with values ranging from ee {sub L} = –0.20% ± 0.14% to ee {sub L} = –2.54% ± 0.28%. The sign of the induced ee {sub L} depends on the helicity and the energy of CPL, but not on the evolutionary stage of the samples, and is the same for all five considered amino acids. Our results support an astrophysical scenario in which the solar system was formed in a high-mass star-forming region where icy grains were irradiated during the protoplanetary phase by an external source of CPL of a given helicity and a dominant energy, inducing a stereo-specific photochemistry.

  20. SORCE Solar Irradiance Data Products

    NASA Astrophysics Data System (ADS)

    Lindholm, D. M.; Pankratz, C. K.; Knapp, B. G.; Meisner, R.; Fontenla, J.; Harder, J. W.; McClintock, W. E.; Kopp, G.; Snow, M.; Woods, T. N.

    2007-12-01

    The Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado manages the SOlar Radiation and Climate Experiment (SORCE) Science Data System. This data processing system routinely produces Total Solar Irradiance (TSI) and Spectral Solar Irradiance (SSI) data products, which are formulated using measurements from the four primary instruments on board the SORCE spacecraft. The TIM instrument provides measurements of the TSI, whereas the SIM, SOLSTICE, and XPS instruments collectively provide measurements of the solar irradiance spectrum from 1 nm to 2400 nm (excluding 31-115nm, which is measured by the SEE instrument on NASA's TIMED mission). The SORCE Science Data System utilizes raw spacecraft and instrument telemetry, calibration data, and other ancillary information to produce a variety of solar irradiance data products that have been corrected for all known instrumental and operational factors. Since launch of the SORCE spacecraft in January 2003, science processing algorithms have continued to mature, and "Level 3" data products (time-averaged and/or spectrally resampled onto uniform wavelength scales) are routinely being produced and delivered to the public via the SORCE web site, and are archived at the Goddard Earth Sciences (GES) Data and Information Services Center (DISC, formerly DAAC). This poster provides an overview of the SORCE data processing system, summarizes the present state of the processing algorithms and future plans, describes the quality of the current SORCE data products, and provides details on how to access SORCE science data.

  1. Updates to ISO 21348 (determining solar irradiances)

    NASA Astrophysics Data System (ADS)

    Tobiska, W. Kent

    2012-07-01

    The ISO 21348 (Determining Solar Irradiances) International Standard is going through a document update. A consensus solar spectrum, solar indices/proxies descriptions, solar model descriptions, and solar measurement descriptions are among the Annexes that are proposed to the standard. These topics will be reviewed and described. The International Standards Organization (ISO) published IS 21348 in 2007 after 7 years of development by the international scientific community. In ISO, documents are reviewed on a regular basis and reaffirmed, updated, or deleted according to the votes of national delegations represented in ISO. IS 21348 provides guidelines for specifying the process of determining solar irradiances. Solar irradiances are reported through products such as measurement sets, reference spectra, empirical models, theoretical models and solar irradiance proxies or indices. These products are used in scientific and engineering applications to characterize within the natural space environment solar irradiances that are relevant to space systems and materials. Examples of applications using input solar irradiance energy include the determination of atmospheric densities for spacecraft orbit determination, attitude control and re-entry calculations, as well as for debris mitigation and collision avoidance activity. Direct and indirect pressure from solar irradiance upon spacecraft surfaces also affects attitude control separately from atmospheric density effects. Solar irradiances are used to provide inputs for a) calculations of ionospheric parameters, b) photon-induced radiation effects, and c) radiative transfer modeling of planetary atmospheres. Input solar irradiance energy is used to characterize material properties related to spacecraft thermal control, including surface temperatures, reflectivity, absorption and degradation. Solar energy applications requiring a standard process for determining solar irradiance energy include i) solar cell power simulation, ii) material degradation, and iii) the development of lamps and filters for terrestrial solar simulators. A solar irradiance product certifies compliance with this process-based standard by following compliance criteria that are described in this International Standard.

  2. SORCE Solar Irradiance Data Products

    NASA Astrophysics Data System (ADS)

    Pankratz, C. K.; Knapp, B. G.; Fontenla, J. M.; Rottman, G. J.; Woods, T. N.; Harder, J. W.; Kopp, G.; McClintock, W. E.; Snow, M.

    2005-05-01

    The SORCE Science Data System produces Total Solar Irradiance (TSI) and Spectral Solar Irradiance (SSI) data products on a daily basis, which are formulated using measurements from the four primary instruments on board the SORCE spacecraft. The TIM instrument provides measurements of the TSI, whereas the SIM, SOLSTICE, and XPS instruments collectively provide measurements of the solar irradiance spectrum from 1 nm to 3000 nm (excluding 31-115nm, which is covered by the TIMED SEE experiment). The Science Data System utilizes raw spacecraft and instrument telemetry, calibration data, and other ancillary information to produce a variety of data products that have been corrected for all known instrumental and operational factors. Since launch of the SORCE spacecraft in January 2003, science processing algorithms have continued to mature, and "Level 3" data products are routinely being produced and delivered to the public via the SORCE web site and the Goddard Earth Sciences (GES) Distributed Active Archive Center (DAAC). This poster provides an overview of the SORCE data processing system, summarizes the present state of the processing algorithms and the quality of the current SORCE data products, and provides details on how to access SORCE science data.

  3. SORCE Solar Irradiance Data Products

    NASA Astrophysics Data System (ADS)

    Pankratz, C. K.; Knapp, B. G.; Fontenla, J. M.; Rottman, G. J.; Woods, T. N.; Harder, J. W.; Kopp, G.; McClintock, W. E.; Snow, M.

    2005-12-01

    The SORCE Science Data System produces Total Solar Irradiance (TSI) and Spectral Solar Irradiance (SSI) data products on a daily basis, which are formulated using measurements from the four primary instruments on board the SORCE spacecraft. The TIM instrument provides measurements of the TSI, whereas the SIM, SOLSTICE, and XPS instruments collectively provide measurements of the solar irradiance spectrum from 1 nm to 2700 nm (excluding 31-115 nm, which is measured by the TIMED SEE experiment). The Science Data System utilizes raw spacecraft and instrument telemetry, calibration data, and other ancillary information to produce a variety of data products that have been corrected for all known instrumental and operational factors. Since launch of the SORCE spacecraft in January 2003, science processing algorithms have continued to mature, and "Level 3" data products are routinely being produced and delivered to the public via the SORCE web site and the Goddard Earth Sciences (GES) Distributed Active Archive Center (DAAC). This poster provides an overview of the SORCE data processing system, summarizes the present state of the processing algorithms and future plans, describes the quality of the current SORCE data products, and provides details on how to access SORCE science data. The NPOESS TSIS instrument package will also include TIM and SIM instruments, having direct flight heritage from the SORCE mission, and will produce data products similar to those produced by the existing SORCE Science Data System.

  4. SIPS: Solar Irradiance Prediction System Stefan Achleitner

    E-print Network

    Cerpa, Alberto E.

    SIPS: Solar Irradiance Prediction System Stefan Achleitner Computer Science and Engineering the variability and dynamics are the largest. We propose SIPS, Solar Irradiance Prediction System, a novel sensing-scaling capacities of renewable energy sources such as wind and solar. However, variability and uncertainty in power

  5. On the depth-dependent production of radionuclides (44?A?59) by solar protons in extraterrestrial matter

    Microsoft Academic Search

    R. Michel; G. Brinkmann

    1980-01-01

    In order to interpret cosmogenic radionuclides in extraterrestrial matter one has to differentiate between p- and ?-induced\\u000a reactions with solar (SCR) and with galactic (GCR) cosmic rays. Our earlier studies have shown that for a satisfactory description\\u000a of GCR-interactions with dense matter rather few but characteristic high energy cross sections are required. In contrast,\\u000a for the low and medium energy

  6. ISO 21348 - Process for determining solar irradiances

    NASA Astrophysics Data System (ADS)

    Tobiska, W.; Nusinov, A.

    A new international standard is being published by the International Standards Organization ISO The document ISO 21348 Space Environment natural and artificial -- Process for determining solar irradiances describes the process for representing solar irradiances We report on the content of the final version of this new standard Because solar irradiance measurements and modeling are constantly evolving through improved instrumentation measurement techniques and modeling capabilities the new standard has been written as a process-based standard to encourage development in solar irradiance determination The standard covers all representations of solar irradiances and is applicable to measurements reference spectra empirical models physics-based models as well as solar proxies and indices The purpose of the standard is to provide a common specification for all solar irradiances for use by space systems materials and environment users A solar irradiance product or specification is compliant with the standard if four criteria are followed First solar irradiances are reported at the minimum in SI units of Watts per square meter corrected to 1 AU Second the method of determining irradiances is documented for data collection processing archiving validation accuracy precision methodology and algorithm information Where applicable a description of proxies and independent data sets used in the derivation of empirical models including the rationale for proxy selection and the mathematical formulation for numerical models is

  7. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites.

    PubMed

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H; Ramasse, Quentin M; Hoppe, Peter; Nittler, Larry R

    2014-10-28

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight (15)N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C-O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C-O bonding environments and nanoglobular organics with dominant aromatic and C-N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid. PMID:25288736

  8. Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites

    PubMed Central

    Vollmer, Christian; Kepaptsoglou, Demie; Leitner, Jan; Busemann, Henner; Spring, Nicole H.; Ramasse, Quentin M.; Hoppe, Peter; Nittler, Larry R.

    2014-01-01

    Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight 15N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C–O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C–O bonding environments and nanoglobular organics with dominant aromatic and C–N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid. PMID:25288736

  9. Correlations of solar cycle 22 UV irradiance

    NASA Technical Reports Server (NTRS)

    Floyd, L.; Brueckner, G.; Crane, P.; Prinz, D.; Herring, L.

    1997-01-01

    The solar ultraviolet spectral irradiance monitor (SUSIM) onboard the upper atmosphere research satellite (UARS) is an absolutely calibrated UV spectrometer which has measured the solar spectral irradiance over the wavelengths 115 nm to 410 nm since October 1991. This data set now extends for about six years from near the peak of solar cycle 22, through its minimum, to the initial rise associated with solar cycle 23. Generally, the time series of UV spectral irradiances obtained shows behavior similar to that of other solar activity indices. The conditions on the sun, which can in result in dominant 13.5-day periodicity, are analyzed and illustrated. It is found that any combination of presence or absence of dominant 13.5-day in UV irradiance and solar wind velocity is possible depending entirely on the particular surface distribution and orientation of solar active regions.

  10. The LASP Interactive Solar IRradiance Datacenter (LISIRD)

    NASA Astrophysics Data System (ADS)

    Pankratz, C. K.; Lindholm, D. M.; Snow, M.; Knapp, B.; Woodraska, D.; Templeman, B.; Woods, T. N.; Eparvier, F. G.; Fontenla, J.; Harder, J.; McClintock, W. E.

    2007-12-01

    The Laboratory for Atmospheric and Space Physics (LASP) has been making space-based measurements of solar irradiance for many decades, and thus has established an extensive catalog of past and ongoing space- based solar irradiance measurements. In order to maximize the accessibility and usability of solar irradiance data and information from multiple missions, LASP is developing the LASP Interactive Solar IRradiance Datacenter (LISIRD) to better serve the needs of researchers, educators, and the general public. This data center is providing interactive and direct access to a comprehensive set of solar spectral irradiance measurements from the soft X-ray (XUV) at 0.1 nm up to the near infrared (NIR) at 2400 nm, as well as state-of-the-art measurements of Total Solar Irradiance (TSI). LASP researchers are also responsible for an extensive set of solar irradiance models and historical solar irradiance reconstructions, which will also be accessible via this data center over time. LISIRD currently provides access to solar irradiance data sets from the SORCE, TIMED-SEE, UARS-SOLSTICE, and SME instruments, spanning 1981 to the present, as well as a Lyman Alpha composite that is available from 1947 to the present. LISIRD also provides data products of interest to the space weather community, whose needs demand high time cadence and near real-time data delivery. This poster provides an overview of the LISIRD system, summarizes the data sets currently available, describes future plans and capabilities, and provides details on how to access solar irradiance data through LISIRD's various interfaces.

  11. The LASP Interactive Solar IRradiance Datacenter (LISIRD)

    NASA Astrophysics Data System (ADS)

    Snow, M.; Woods, T. N.; Eparvier, F. G.; Fontenla, J.; Harder, J.; McClintock, W. E.; Pankratz, C.; Richard, E.; Windnagel, A.; Woodraska, D.

    2005-12-01

    LASP has created an online resource for combined solar irradiance datasets from the SORCE, TIMED, UARS, and SME missions. The LASP Interactive Solar IRradiance Datacenter (LISIRD) not only provides unified access to the individual datasets, but also combines them for ease of use by scientists, educators, and the general public. In particular, LISIRD makes available composite spectra and time series. The TIMED SEE, SORCE SOLSTICE, and SORCE SIM instruments produce spectra that together cover the solar spectrum from 1 to 2700 nm. Through the LISIRD interface, the user can get data that bridges the various missions in both wavelength and time. LISIRD also hosts data products of interest to the space weather community. They have slightly different needs than the atmospheric modelers that are the typical users of irradiance data. For space weather applications, high time cadence and near real-time data delivery are key. For these users, we make our observations available shortly after spacecraft contact, and append the observations to a single data file which they can retrieve using anonymous ftp every few hours. The third component of LISIRD is the Solar Physical Radiation Model (SPRM) results of Fontenla et al. It provides a model of current solar activity, the synthetic spectral irradiance, and tools that permit one to model the solar activity source of the spectral irradiance variations.

  12. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    NASA Technical Reports Server (NTRS)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; Lowther, S. E.; Lillehei, P. T.; Bryant, R. G.

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  13. Nanostructured solar irradiation control materials for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Kang, Jin Ho; Marshall, Iseley A.; Torrico, Mattew N.; Taylor, Chase R.; Ely, Jeffry; Henderson, Angel; Sauti, Godfrey; Gibbons, Luke J.; Kim, Jae-Woo; Park, Cheol; Lowther, Sharon E.; Lillehei, Peter T.; Bryant, Robert G.

    2012-10-01

    Tailoring the solar absorptivity (?s) and thermal emissivity (?T) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The ?s and ?T were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the ?s and ?T by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  14. Extraterrestrial Samples at JSC

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.

    2007-01-01

    A viewgraph presentation on the curation of extraterrestrial samples at NASA Johnson Space Center is shown. The topics include: 1) Apollo lunar samples; 2) Meteorites from Antarctica; 3) Cosmic dust from the stratosphere; 4) Genesis solar wind ions; 5) Stardust comet and interstellar grains; and 5) Space-Exposed Hardware.

  15. Curation of Extraterrestrial Samples

    Microsoft Academic Search

    C. Allen

    2002-01-01

    NASA's current collection of extraterrestrial materials includes the Apollo lunar samples, meteorites collected in Antarctica, cosmic dust, and space-exposed hardware. During the current decade, samples are expected to be returned by spacecraft from the solar wind, a comet, and an asteroid. Future sample return missions to Mars and diverse other bodies have been planned or recommended. Curation, an integral part

  16. 4, 84398469, 2004 Solar irradiance

    E-print Network

    Paris-Sud XI, Université de

    al. (1984) solar spectrum (Fontenla et al., 1999, called MODTRAN 3.5) in the visible10 spectral range 500­650 nm, where the SOLSPEC is -1.3% lower than MODTRAN 3.5. Comparison of the SCIAMACHY solar spectrum from channels 1 to 4 (­ re-calibrated by the University of Bremen ­) with MODTRAN 3.5 indicates

  17. Remund J., Wald L., Lefevre M., Ranchin T., Page J., 2003. Worldwide Linke turbidity information. Proceedings of ISES Solar World Congress, 16-19 June, Gteborg, Sweden, CD-ROM published by International Solar Energy

    E-print Network

    Paris-Sud XI, Université de

    , Mireille Lefèvre and Thierry Ranchin Ecole des Mines de Paris /Armines, Groupe Teledetection & Modelisation, that is the extraterrestrial irradiance normal to the solar beam at the mean solar distance. It is equal to 1367 Wm-2

  18. Solar Irradiance and Thermospheric Airglow Rocket Experiments

    NASA Technical Reports Server (NTRS)

    Solomon, Stanley C.

    1998-01-01

    This report describes work done in support of the Solar Irradiance and Thermospheric Air-glow Rocket Experiments at the University of Colorado for NASA grant NAG5-5021 under the direction of Dr. Stanley C. Solomon. (The overall rocket program is directed by Dr. Thomas N. Woods, formerly at the National Center for Atmospheric Research, and now also at the University of Colorado, for NASA grant NAG5-5141.) Grant NAG5-5021 provided assistance to the overall program through analysis of airglow and solar data, support of two graduate students, laboratory technical services, and field support. The general goals of the rocket program were to measure the solar extreme ultraviolet spectral irradiance, measure the terrestrial far-ultraviolet airglow, and analyze their relationship at various levels of solar activity, including near solar minimum. These have been met, as shown below. In addition, we have used the attenuation of solar radiation as the rocket descends through the thermosphere to measure density changes. This work demonstrates the maturity of the observational and modeling methods connecting energetic solar photon fluxes and airglow emissions through the processes of photoionization and photoelectron production and loss. Without a simultaneous photoelectron measurement, some aspects of this relationship remain obscure, and there are still questions pertaining to cascade contributions to molecular and atomic airglow emissions. However, by removing the solar irradiance as an "adjustable parameter" in the analysis, significant progress has been made toward understanding the relationship of far-ultraviolet airglow emissions to the solar and atmospheric conditions that control them.

  19. Inferring Total and Spectral Solar Irradiance From Sunspot Areas Only

    Microsoft Academic Search

    D. G. Preminger; S. R. Walton

    2004-01-01

    We show that daily sunspot area can be used in simple models to reconstruct daily variations in total or spectral solar irradiance. The models assume that all solar irradiance fluctuations can be traced back to the emergence of sunspots on the solar disk. Cotemporal data for irradiance and sunspot area are analysed to extract a detailed impulse response function that

  20. Studies of Solar EUV Irradiance from SOHO

    NASA Technical Reports Server (NTRS)

    Floyd, Linton

    2002-01-01

    The Extreme Ultraviolet (EUV) irradiance central and first order channel time series (COC and FOC) from the Solar EUV Monitor aboard the Solar and Heliospheric observatory (SOHO) issued in early 2002 covering the time period 1/1/96-31/1201 were analyzed in terms of other solar measurements and indices. A significant solar proton effect in the first order irradiance was found and characterized. When this effect is removed, the two irradiance time series are almost perfectly correlated. Earlier studies have shown good correlation between the FOC and the Hall core-to-wing ratio and likewise, it was the strongest component of the COC. Analysis of the FOC showed dependence on the F10.7 radio flux. Analysis of the CDC signals showed additional dependences on F10.7 and the GOES x-ray fluxes. The SEM FOC was also well correlated with thein 30.4 nm channel of the SOHO EUV Imaging Telescope (EIT). The irradiance derived from all four EIT channels (30.4 nm, 17.1 nm, 28.4 nm, and 19.5 nm) showed better correlation with MgII than F10.7.

  1. Studies of Solar EUV Irradiance from SOHO

    NASA Astrophysics Data System (ADS)

    Floyd, Linton

    2002-06-01

    The Extreme Ultraviolet (EUV) irradiance central and first order channel time series (COC and FOC) from the Solar EUV Monitor aboard the Solar and Heliospheric observatory (SOHO) issued in early 2002 covering the time period 1/1/96-31/1201 were analyzed in terms of other solar measurements and indices. A significant solar proton effect in the first order irradiance was found and characterized. When this effect is removed, the two irradiance time series are almost perfectly correlated. Earlier studies have shown good correlation between the FOC and the Hall core-to-wing ratio and likewise, it was the strongest component of the COC. Analysis of the FOC showed dependence on the F10.7 radio flux. Analysis of the CDC signals showed additional dependences on F10.7 and the GOES x-ray fluxes. The SEM FOC was also well correlated with thein 30.4 nm channel of the SOHO EUV Imaging Telescope (EIT). The irradiance derived from all four EIT channels (30.4 nm, 17.1 nm, 28.4 nm, and 19.5 nm) showed better correlation with MgII than F10.7.

  2. Spallation reactions in extraterrestrial matter

    SciTech Connect

    Michel, Rolf [Zentrum fuer Strahlenschutz und Radiooekologie, Universitaet Hannover, Am Kleinen Felde 30, D-30167 Hannover (Germany)

    1998-02-15

    This paper describes the cosmic-ray-induced production of stable and radioactive residual nuclides, the so-called cosmogenic nuclides. In extraterrestrial solar-system matter, i.e. planetary surfaces, meteorites, cosmic dust and the heavy component of the galactic cosmic radiation, these nuclides are experimentally observable as positive anomalies of isotopic abundances. They preserve a record of cosmic ray exposure which can be interpreted with respect to the collision and exposure history of the irradiated objects as well as to intensities and spectral distributions of cosmic ray particles in the past. To decipher the cosmic ray record in extraterrestrial matter and to obtain information which cannot be obtained by any other means reliable models are needed for the calculation of the production rates of cosmogenic nuclides. On the basis of thin-target and thick-target accelerator experiments such a model has been developed which is applied here exemplarily to interprete cosmogenic nuclide abundances in stony meteorites and lunar surface materials.

  3. Total Solar Irradiance Variability and the Solar Activity Cycle

    E-print Network

    Probhas Raychaudhuri

    2006-05-06

    It is suggested that the solar variability is due to the perturbed nature of the solar core and this variability is provided by the variability of the solar neutrino flux from the solar neutrino detectors i.e., Homestake, Superkamiokande, SAGE and GALLEX-GNO. The solar neutrino flux in the standard solar model (SSM) was calculated on the assumption of L_nu (neutrino luminosity) = L_gamma (optical luminosity) which implies that if there is a change in optical luminosity then solar neutrino flux data will also be changed. An internal dynamo due to the cyclic variation of nuclear energy generation inside the core of the sun is responsible for the solar activity cycle was suggested and thus the internal magnetic field is also variable. Again the changes in the nuclear energy generation induce structural changes that result in variations of the global solar parameters i.e., luminosity, radius and temperatures etc. From the analysis of total solar irradiance (TSI) data during the year from 1970 to 2003 we have found five phases within the solar activity cycle. The first phase (I) starts before two years from the sunspot minimum. The second phase (II) starts at the time of sunspot minimum and phase (III) starts before 2/3 years from sunspot maximum whereas phase (IV) starts at sunspot maximum and fifth phase (V) starts at after 2-3 years from sunspot maximum.

  4. Direct solar radiation - Spectrum and irradiance derived from sun-photometer measurements

    NASA Astrophysics Data System (ADS)

    Wobrock, Wolfram; Eiden, Reiner

    1988-06-01

    The continuous spectrum of the direct solar radiation from wavelength = 330 to 2690 nm, penetrating a cloudless atmosphere and arriving on the earth surface, is determined by measuring the solar irradiance in ten selected discrete spectral ranges defined by interference filters. Heretofore knowledge of the extraterrestrial solar spectrum has been required as well as of the transmittance functions to describe the spectral optical properties of the atmosphere. A set of appropriate and simple functions is given and discussed, which allows calculation of the molecular, aerosol, oxygen, and ozone optical thicknesses. The influence of atmospheric water vapor is considered through line by line calculations. The dominant and most fluctuating extinction parameters are the aerosol optical thickness and the content of precipitable water vapor. These are obtained by measurements with two sun photometers, developed according to the World Meteorological Organization recommendation. To test the derived solar spectrum at ground level the photometers are also run with nine broadband filters. The values observed differ little from those obtained by integration of the deduced spectral irradiance. Furthermore, the integral value of the resulting entire spectrum agrees reasonably well with the total direct irradiance gained from actinometer measurements.

  5. Forecasting solar extreme and far ultraviolet irradiance

    NASA Astrophysics Data System (ADS)

    Henney, C. J.; Hock, R. A.; Schooley, A. K.; Toussaint, W. A.; White, S. M.; Arge, C. N.

    2015-03-01

    A new method is presented to forecast the solar irradiance of selected wavelength ranges within the extreme ultraviolet (EUV) and far ultraviolet (FUV) bands. The technique is similar to a method recently published by Henney et al. (2012) to predict solar 10.7 cm (2.8 GHz) radio flux, abbreviated F10.7, utilizing advanced predictions of the global solar magnetic field generated by a flux transport model. In this and the previous study, we find good correlation between the absolute value of the observed photospheric magnetic field and selected EUV/FUV spectral bands. By evolving solar magnetic maps forward 1 to 7 days with a flux transport model, estimations of the Earth side solar magnetic field distribution are generated and used to forecast irradiance. For example, Pearson correlation coefficient values of 0.99, 0.99, and 0.98 are found for 1 day, 3 day, and 7 day predictions, respectively, of the EUV band from 29 to 32 nm. In the FUV, for example, the 160 to 165 nm spectral band, correlation values of 0.98, 0.97, and 0.96 are found for 1 day, 3 day, and 7 day predictions, respectively. In the previous study, the observed F10.7 signal is found to correlate well with strong magnetic field (i.e., sunspot) regions. Here we find that solar EUV and FUV signals are significantly correlated with the weaker magnetic fields associated with plage regions, suggesting that solar magnetic indices may provide an improved indicator (relative to the widely used F10.7 signal) of EUV and FUV nonflaring irradiance variability as input to ionospheric and thermospheric models.

  6. P5.60B DERIVATION OF DAYLIGHT AND SOLAR IRRADIANCE DATA FROM SATELLITE OBSERVATIONS

    E-print Network

    Heinemann, Detlev

    . Fontoynont (ENTPE Vaulx-en-Velin, France) L. Wald (Ecole des Mines, Sophia-Antipolis, France) H. G. Beyer global irradiance under a clear sky Iclear (Bourges, 1979). Instead, here the extraterrestrial global

  7. Active-region evolution and solar rotation variations in solar UV irradiance, total solar irradiance, and soft X rays

    NASA Technical Reports Server (NTRS)

    Donnelly, R. F.; Heath, D. F.; Lean, J. L.

    1982-01-01

    Variations in the total solar irradiance, solar UV spectral irradiance, and solar soft X-ray emission caused by active region evolution and solar rotation are analyzed by using concurrent measurements from the NIMBUS 7 and GOES satellites. The observations are interpreted by using simple empirical models that relate ground-based observations of the size and location of sunspots and plages to the full-disk temporal variations. It is found that the major dips in the photospheric total solar irradiance S, which are evident in both satellite measurements and model predictions, are usually not accompanied by outstanding enhancements in the chromospheric and upper photospheric UV spectral irradiance or coronal X rays. The main cause of this difference between the variability of S and of the UV flux is that the total chromospheric plage enhancements are not outstanding at those times when the total sunspot are outstanding. X rays are even more variable because of a much wider CMD sensitivity.

  8. Solar variability in irradiance and oscillations

    NASA Technical Reports Server (NTRS)

    Kuhn, Jeff R.

    1995-01-01

    The signature of the solar cycle appears in helioseismic frequencies and splittings. It is known that the changing outer superadiabatic region of the sun is responsible for this. The deeper solar-cycle mechanism from the surface changes, and, in particular, how magnetic fields perturb the global modes, the solar irradiance and the luminosity, is discussed. The irradiance and helioseismic changes are described. The interpretation of seismic and photometric data is discussed, considering current one-dimensional models and phenomenology. It is discussed how the long term solar-cycle luminosity effect could be caused by changes occurring near the base of the convection zone (CZ). It is shown that a thin toroidal flux sheath at the top of the radiative zone changed the thermal stratification immediately below the CZ over a solar-cycle timescale in two ways: the temperature of the magnetized fluid becomes hotter than the surrounding fluid, and the temperature gradient steepens above the magnetized region. The testing of CZ dynamics and extension of numerical experiments to global scales are considered.

  9. The Role of Radiation in the Solar Nebula: Correlated Chemistry-Structure- Isotope Studies of Laboratory and Extraterrestrial Organics

    NASA Astrophysics Data System (ADS)

    Nittler, Larry

    This proposal outlines an interdisciplinary effort aimed at quantitatively evaluating the roles that irradiation played in the evolution of ices and organics in the solar nebula and the potential trapping of noble gases in primitive solids. The collective effort outlined here and in two partnered proposals (PIs Scott Sandford and Fred Ciesla) involves individuals at five primary institutions. We define a series of coordinated experimental, theoretical, and observational projects that are necessary to begin to recognize and understand the complex effects of irradiation in the early Solar System. This coordinated effort is in line with the latest emphasis on interdisciplinary work by the Origins of Solar System program. The specific goal of the CIW-NRL component of the effort is to conduct comparative studies of the isotope composition, chemistry and structure of organic residues from ices subjected to controlled radiation exposures, with those of organic matter in primitive Solar System materials, primarily interplanetary dust particles (IDPs). Three broad tasks will be undertaken: 1) Evaluate the extent to which organic molecules were formed and restructured as they and their icy precursors were irradiated by UV, x-rays and cosmic-rays in the solar nebula. Specifically, we will revisit the model of Ciesla and Sandford (Science, 2012), and evaluate the irradiation doses seen by ices and organics in the disk, as well as the chemical evolution of these species as they move through more realistic disk structures. The detailed consequences of this irradiation, as well as the rates and fluences required to drive changes in chemistry and physical structure, will be determined by complementary experiments and analytic studies. 2) Quantitatively explore the history of noble gases in ices and organics in the outer solar nebula as water ice is desorbed (due to thermal or photo effects) and reformed in the solar nebula. We will also explore how such ices are irradiated and the structural changes that occur in these ices and resulting photo-products. We will determine the extent to which noble gases remain trapped in these ices after processing and in the residues that form from this irradiation, and the extent to which this residue replicates the properties of the enigmatic phase Q carrier of noble gases in meteorites. 3) Determine the isotopic effects of C, H, and N induced by irradiation of ices and organics. We will carry out experiments to determine how enrichments in heavy isotopes may be passed forward from target ices into organics and the extent to which irradiation itself results in isotopic differences between target materials and residues. These results will be combined with dynamical models to determine the range of isotopic ratios expected from irradiative processing in the solar nebula. Each of these experimental and theoretical tasks will be complemented by coordinated microanalytical (chemical-microstructural-isotopic) studies of relevant, naturally- occurring, organic matter in anhydrous chondritic porous IDPs and, if available, ultracarbonaceous micrometeorites. Both are among the most primitive planetary materials available for laboratory study. These observations will be used to better understand the range of properties of early Solar System organic matter and to directly search for evidence of the radiation processing signatures identified by the three major tasks above. Thus, the IDP and micrometeorite analyses are necessary to provide ground-truth for the extensive theoretical and experimental work.

  10. A simple spectral solar irradiance model for cloudless maritime atmospheres

    Microsoft Academic Search

    WATSON W. GREGG; K. L. CARDER

    1990-01-01

    A simple spectral atmospheric radiative transfer model specific for oceanographic applications begins with spectral extraterrestrial solar u-radiance corrected for earth-sun orbital distance. Ir- radiance is then attenuated in passing through the atmosphere by Rayleigh scattering, ozone, oxygen, and water vapor absorption, and marine aerosol scattering and absorption, and is finally reduced by reflectance at the air-sea interface. The model is

  11. Solar Irradiance Data Products at the LASP Interactive Solar IRradiance Datacenter (LISIRD)

    NASA Astrophysics Data System (ADS)

    Lindholm, D. M.; Ware DeWolfe, A.; Wilson, A.; Pankratz, C. K.; Snow, M. A.; Woods, T. N.

    2011-12-01

    The Laboratory for Atmospheric and Space Physics (LASP) has developed the LASP Interactive Solar IRradiance Datacenter (LISIRD, http://lasp.colorado.edu/lisird/) web site to provide access to a comprehensive set of solar irradiance measurements and related datasets. Current data holdings include products from NASA missions SORCE, UARS, SME, and TIMED-SEE. The data provided covers a wavelength range from soft X-ray (XUV) at 0.1 nm up to the near infrared (NIR) at 2400 nm, as well as Total Solar Irradiance (TSI). Other datasets include solar indices, spectral and flare models, solar images, and more. The LISIRD web site features updated plotting, browsing, and download capabilities enabled by dygraphs, JavaScript, and Ajax calls to the LASP Time Series Server (LaTiS). In addition to the web browser interface, most of the LISIRD datasets can be accessed via the LaTiS web service interface that supports the OPeNDAP standard. OPeNDAP clients and other programming APIs are available for making requests that subset, aggregate, or filter data on the server before it is transported to the user. This poster provides an overview of the LISIRD system, summarizes the datasets currently available, and provides details on how to access solar irradiance data products through LISIRD's interfaces.

  12. The calculated influence of atmospheric conditions on solar cell ISC under direct and global solar irradiances

    NASA Technical Reports Server (NTRS)

    Mueller, Robert L.

    1987-01-01

    Calculations of the influence of atmospheric conditions on solar cell short-circuit current (Isc) are made using a recently developed computer model for solar spectral irradiance distribution. The results isolate the dependence of Isc on changes in the spectral irradiance distribution without the direct influence of the total irradiance level. The calculated direct normal irradiance and percent diffuse irradiance are given as a reference to indicate the expected irradiance levels. This method can be applied to the calibration of photovoltaic reference cells. Graphic examples are provided for amorphous silicon and monocrystalline silicon solar cells under direct normal and global normal solar irradiances.

  13. The calculated influence of atmospheric conditions on solar cell ISC under direct and global solar irradiances

    NASA Astrophysics Data System (ADS)

    Mueller, Robert L.

    Calculations of the influence of atmospheric conditions on solar cell short-circuit current (Isc) are made using a recently developed computer model for solar spectral irradiance distribution. The results isolate the dependence of Isc on changes in the spectral irradiance distribution without the direct influence of the total irradiance level. The calculated direct normal irradiance and percent diffuse irradiance are given as a reference to indicate the expected irradiance levels. This method can be applied to the calibration of photovoltaic reference cells. Graphic examples are provided for amorphous silicon and monocrystalline silicon solar cells under direct normal and global normal solar irradiances.

  14. Modelling solar irradiance from HRV images of Meteosat Second Generation

    Microsoft Academic Search

    Marco Cony; Luis Zarzalejo; Jesús Polo; Ruth Marchante; Luis Martín

    2010-01-01

    Knowledge of solar radiation at the earth's surface is a need in designing any solar energy application. In particular both photovoltaic and solar thermal systems required high accurate data of solar radiation components. Nowadays the use of satellite images as input to models for deriving solar irradiance time series is accepted as a reliable methodology with good accuracy. In this

  15. Extraterrestrial Materials: The Role of Synchrotron Radiation Analyses in the Study of our Solar System

    SciTech Connect

    Sutton, Stephen R. [University of Chicago

    2006-04-05

    Sample-return missions and natural collection processes have provided us with a surprisingly extensive collection of matter from Solar System bodies other than the Earth. These collections include samples from the Moon, Mars, asteroids, interplanetary dust, and, recently, from the Sun (solar wind) and a comet. This presentation will describe some of these materials, how they were collected, and what we have learned from them. Synchrotron radiation analyses of these materials are playing an increasingly valuable role in unraveling the histories and properities of the parent Solar System bodies.

  16. Xenon and krypton isotopes in extraterrestrial regolith soils and in the solar wind

    Microsoft Academic Search

    R. O. Pepin; R. H. Becker; P. E. Rider

    1995-01-01

    Isotopic distributions of pure solar-wind xenon and krypton are derived from an extensive data base of xenon and krypton compositions evolved from lunar and meteoritic regolith samples by acid-etching or combustion-pyrolysis experiments in several different laboratories. Regolith Xe and Kr are nonuniform mixtures of primary solar-wind components with others arising in situ from cosmic-ray spallation, neutron-capture in iodine and bromine,

  17. Periodicities of solar irradiance and solar activity indices

    Microsoft Academic Search

    Judit Pap; S. David Bouwer; W. Kent Tobiska

    1990-01-01

    The present FFT time-series analysis indicates the presence of an 8-11 month periodicity in solar total and UV irradiances, sunspot-blocking function, 10.7-cm radio flux, and Ca-K plage index. While the 51-day period is the dominant one in the projected areas of developing complex sunspot groups, it is missing from the old, decaying sunspot areas, thereby suggesting that the 51-day period

  18. Extraterrestrial Communications.

    ERIC Educational Resources Information Center

    Deardorff, James W.

    1987-01-01

    Discusses the embargo hypothesis--the theory that Earth is apparently free from alien exploitation because of a presumed cosmic quarantine against this planet--which implies that, instead of being only a few hundred years technologically in advance of earthly civilization, extraterrestrials in charge are likely tens of thousands of years in…

  19. Solar Irradiance Data Products at the LASP Interactive Solar IRradiance Datacenter (LISIRD)

    NASA Astrophysics Data System (ADS)

    Ware Dewolfe, A.; Wilson, A.; Lindholm, D. M.; Pankratz, C. K.; Snow, M. A.; Woods, T. N.

    2010-12-01

    The Laboratory for Atmospheric and Space Physics (LASP) has developed the LASP Interactive Solar IRradiance Datacenter (LISIRD) to provide access to a comprehensive set of solar irradiance measurements. LISIRD has recently been updated to serve many new datasets and models, including data from SORCE, UARS-SOLSTICE, SME, and TIMED-SEE, and model data from the Flare Irradiance Spectral Model (FISM). The user interface emphasizes web-based interactive visualizations, allowing users to explore and compare this data before downloading it for analysis. The data provided covers a wavelength range from soft X-ray (XUV) at 0.1 nm up to the near infrared (NIR) at 2400 nm, as well as wavelength-independent Total Solar Irradiance (TSI). Combined data from the SORCE, TIMED-SEE, UARS-SOLSTICE, and SME instruments provide continuous coverage from 1981 to the present, while Lyman-alpha measurements, FISM daily data, and TSI models date from the 1940s to the present. LISIRD will also host Glory TSI data as part of the SORCE data system. This poster provides an overview of the LISIRD system, summarizes the data sets currently available, describes future plans and capabilities, and provides details on how to access solar irradiance data through LISIRD’s interfaces.

  20. Cosmogenic nuclides in extraterrestrial materials

    Microsoft Academic Search

    S. Vogt; G. F. Herzog; R. C. Reedy

    1990-01-01

    Research on cosmogenic nuclides in extraterrestrial materials is summarized. Methods for determining average production rates in meteorites are considered as well as the composition dependence of production rates. Also discussed are lunar meteorites, solar-gas-rich meteorites, presolar grains, and solar cosmic rays. 202 refs.

  1. Cosmogenic nuclides in extraterrestrial materials

    SciTech Connect

    Vogt, S.; Herzog, G.F.; Reedy, R.C. (Rutgers Univ., New Brunswick, NJ (USA) Los Alamos National Lab., NM (USA))

    1990-08-01

    Research on cosmogenic nuclides in extraterrestrial materials is summarized. Methods for determining average production rates in meteorites are considered as well as the composition dependence of production rates. Also discussed are lunar meteorites, solar-gas-rich meteorites, presolar grains, and solar cosmic rays. 202 refs.

  2. Solar Irradiance Variations on Active Region Time Scales

    NASA Technical Reports Server (NTRS)

    Labonte, B. J. (editor); Chapman, G. A. (editor); Hudson, H. S. (editor); Willson, R. C. (editor)

    1984-01-01

    The variations of the total solar irradiance is an important tool for studying the Sun, thanks to the development of very precise sensors such as the ACRIM instrument on board the Solar Maximum Mission. The largest variations of the total irradiance occur on time scales of a few days are caused by solar active regions, especially sunspots. Efforts were made to describe the active region effects on total and spectral irradiance.

  3. Solar Spectral Irradiance Changes During Cycle 24

    NASA Technical Reports Server (NTRS)

    Marchenko, Sergey; Deland, Matthew

    2014-01-01

    We use solar spectra obtained by the Ozone Monitoring Instrument (OMI) on board the Aura satellite to detect and follow long-term (years) and short-term (weeks) changes in the solar spectral irradiance (SSI) in the 265-500 nm spectral range. During solar Cycle 24, in the relatively line-free regions the SSI changed by approximately 0.6% +/- 0.2% around 265 nm. These changes gradually diminish to 0.15% +/- 0.20% at 500 nm. All strong spectral lines and blends, with the notable exception of the upper Balmer lines, vary in unison with the solar "continuum." Besides the lines with strong chromospheric components, the most involved species include Fe I blends and all prominent CH, NH, and CN spectral bands. Following the general trend seen in the solar "continuum," the variability of spectral lines also decreases toward longer wavelengths. The long-term solar cycle SSI changes are closely, to within the quoted 0.1%-0.2% uncertainties, matched by the appropriately adjusted short-term SSI variations derived from the 27 day rotational modulation cycles. This further strengthens and broadens the prevailing notion about the general scalability of the UV SSI variability to the emissivity changes in the Mg II 280 nm doublet on timescales from weeks to years. We also detect subtle deviations from this general rule: the prominent spectral lines and blends at lambda approximately or greater than 350 nm show slightly more pronounced 27 day SSI changes when compared to the long-term (years) trends. We merge the solar data from Cycle 21 with the current Cycle 24 OMI and GOME-2 observations and provide normalized SSI variations for the 170-795 nm spectral region.

  4. Optimisation of buildings' solar irradiation availability

    SciTech Connect

    Kaempf, Jerome Henri; Montavon, Marylene; Bunyesc, Josep; Robinson, Darren [Solar Energy and Building Physics Laboratory, Station 18, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Bolliger, Raffaele [Industrial Energy Systems Laboratory, Station 9, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)

    2010-04-15

    In order to improve the sustainability of new and existing urban settlements it is desirable to maximise the utilisation of the solar energy incident on the building envelope, whether by passive or active means. To this end we have coupled a multi-objective optimisation algorithm with the backwards ray tracing program RADIANCE which itself uses a cumulative sky model for the computation of incident irradiation (W h/m{sup 2}) in a single simulation. The parameters to optimise are geometric (the height of buildings up to their facade and the height and orientation of roofs), but with the constraint of maintaining an overall built volume, and the objective function is heating season solar irradiation offset by envelope heat losses. This methodology has been applied to a range of urban typologies and produces readily interpretable results. The focus of this work is on the design of new urban forms but the method could equally be applied to examine the relative efficiency of existing urban settlements, by comparison of existing forms with the calculated optima derived from relevant specifications of the building envelope. (author)

  5. LISIRD: LASP Interactive Solar Irradiance Data Center

    NASA Astrophysics Data System (ADS)

    Lindholm, D. M.; Wilson, A.

    2013-12-01

    The Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder has been involved in numerous space-borne missions to directly measure and understand the variability of the Sun's energy output and its impact on global climate change. The LASP Interactive Solar Irradiance Data Center (LISIRD) provides a web site with interactive graphics to explore, subset, and download these and other solar related datasets. The LISIRD collections include observations of total and spectral irradiance with coverage from the X-ray to the infrared from projects such as SME, UARS SOLSTICE, SNOE, TIMED SEE, SORCE, and SDO EVE plus a growing number of related data products, proxies, and models. The LISIRD data services are backed by the LaTiS data server which presents a unified RESTful web service interface to slice, dice, and perform select server-side operations as the data are dynamically streamed to files of your desired format or directly into your code or analysis tools. Come see the data products and services that LISIRD has available and help us to improve them to better meet your needs.

  6. Total solar irradiance monitors, space instruments for measuring total solar irradiance on FY-3 satellites

    NASA Astrophysics Data System (ADS)

    Wang, Hongrui; Wang, Yupeng; Ye, Xin; Wang, Kai; Yang, Dongjun; Fang, Wei; Li, Huiduan

    2014-11-01

    Total Solar Irradiance (TSI) has been recorded daily by Total Solar Irradiance Monitors (TSIM) with overlapping measurements on FY-3 (Feng Yun-3) series satellites since 2008. Instrument descriptions, operation in space and flight performance of three TSIMs are presented in this paper. TSI is measured by electrical substitution radiometers integrated in TSIM, with traceability to SI. TSIM/FY-3A and TSIM/FY-3B share nearly the same design. Since TSIM/FY-3A and TSIM/FY-3B have no pointing system, the Sun is only observed when the Sunlight sweeps TSIM's field-of-view and TSI measurements are influenced inevitably by solar pointing errors. TSIM/FY-3C, a radiometer package was constructed with a pointing system for solar tracking in order to achieve accurate solar pointing. TSIM/FY-3C was sent into orbit in September 2013 onboard FY-3C satellite. Daily TSI measurements have been performed by TSIM/FY-3C with autonomous accurate solar tracking for 1 year. TSIM/FY-3C is in a good instrument health according to its on-orbit data.

  7. Research of solar simulator irradiance non-uniformity measurement

    Microsoft Academic Search

    Yafei Yuan; Yiqiang Yang; Zhang Ya

    2011-01-01

    The irradiance non-uniformity on test plane of a large area pulsed solar simulator is critical for space solar array electrical characteristic measurement, because it is one of the main error souse of the measurement. Presently, the most commonly used irradiance non-uniformity measurement methods are \\

  8. Reconstruction of solar irradiance since 1610: Implications for climate change

    Microsoft Academic Search

    Judith Lean; Juerg Beer; Raymond Bradley

    1995-01-01

    Solar total and ultraviolet (UV) irradiances are reconstructed annually from 1610 to the present. This epoch includes the Maunder Minimum of anomalously low solar activity (circa 1645-1715) and the subsequent increase to the high levels of the present Modern Maximum. In this reconstruction, the Schwabe (11-year) irradiance cycle and a longer term variability component are determined separately, based on contemporary

  9. Solar irradiance short wave radiation users guide. Final report

    SciTech Connect

    Martinolich, P.; Arnone, R.A.

    1995-05-19

    Solar irradiance for short wave radiation (400-700 nm) at the sea surface can be calculated using inputs obtained from satellite systems and model estimates. The short wave solar irradiance is important for estimating the surface heating that occurs in the near surface and estimating the available irradiance for biological growth in the upper ocean. The variability of the solar irradiance is believed to have significant influence on the global carbon cycle. This users guide provides an understanding of the models and operational procedures for using the software and understanding the results.

  10. Modelling rotational and cyclical spectral solar irradiance variations

    NASA Astrophysics Data System (ADS)

    Unruh, Yvonne

    Solar irradiance changes are highly wavelength dependent: solar-cycle variations in the UV can be on the order of tens of percent, while changes in the visible are typically only of the order of one or two permille. With the launch of a number of instruments to measure spectral solar irradiance, we are now for a first time in a good position to explore the changing solar irradiance over a large range of wavelengths and to test our irradiance models as well as some of their underlying assumptions. I will introduce some of the current modelling approaches and present model-data comparisons, using the SATIRE irradiance model and SORCE/SIM measurements as an example. I will conclude by highlighting a number of outstanding questions regarding the modelling of spectral irradiance and current approaches to address these.

  11. Creation of a composite solar ultraviolet irradiance data set

    Microsoft Academic Search

    Matthew T. DeLand; Richard P. Cebula

    2008-01-01

    Characterization of long-term solar ultraviolet (UV) irradiance variations is important for understanding the radiative forcing of Earth's atmosphere. Extending such a characterization to multidecadal timescales requires the merging of multiple satellite data sets. Currently available irradiance data sets show both absolute offsets and time-dependent differences that vary between spectral ranges. We have created a composite spectral UV irradiance data set

  12. On diamond, graphitic and amorphous carbons in primitive extraterrestrial solar system materials

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1990-01-01

    Carbon is among the most abundant elements in the universe and carbon chemistry in meteorites and comets is an important key to understanding many Solar System and interstellar processes. Yet, the mineralogical properties and interrelations between various structural forms of elemental carbon remain ambiguous. Crystalline elemental carbons include rhombohedral graphite, hexagonal graphite, cubic diamond, hexagonal diamond (i.e., lonsdaleite or carbon-2H) and chaoite. Elemental carbon also occurs as amorphous carbon and poorly graphitized (or turbostratic) carbon but of all the forms of elemental carbon only graphite is stable under physical conditions that prevail in small Solar System bodies and in the interstellar medium. The recent discovery of cubic diamond in carbonaceous chondrites and hexagonal diamond in chondritic interplanetary dust particles (IDPs) have created a renewed interest in the crystalline elemental carbons that were not formed by shock processes on a parent body. Another technique, Raman spectroscopy, confirms a widespread occurrence of disordered graphite in the Allende carbonaceous chondrite and in chondritic IDPs. Elemental carbons have also been identified by their characteristic K-edge features in electron energy loss spectra (EELS). However, the spectroscopic data do not necessarily coincide with those obtained by selected area electron diffraction (SAED). In order to interpret these data in terms of rational crystalline structures, it may be useful to consider the principles underlying electron diffraction and spectroscopic analyses. Electron diffraction depends on electron scattering, on the type of atom and the distance between atoms in a crystal lattice. Spectroscopic data are a function of the type of atom and the energy of bonds between atoms. Also, SAED is a bulk sampling technique when compared to techniques such as Raman spectroscopy or EELS. Thus, it appears that combined analyses provide contradictory results and that amorphous, or short-range ordered, carbon identified by conventional TEM imaging and SAED may show evidence for sp(3) bonds in EELS spectra. It is suggested that complex, nanometer-scale, mineralogical interrelations are common to all elemental carbons irrespective of their origin. The subsequent thermal history, or energy balance, will determine the ultimate microstructure.

  13. TIMED SEE: Eight Years of Solar EUV Spectral Irradiance Measurements

    NASA Astrophysics Data System (ADS)

    Eparvier, Francis; Woods, Thomas; Chamberlin, Phillip; Woodraska, Donald; Hock, Rachel

    The Solar Extreme ultraviolet Experiment (SEE) on board the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite has been providing the scientific com-munity with solar extreme ultraviolet (EUV) spectral irradiance measurements from early 2002 to the present. The SEE dataset spans the wavelength range from 0.1 nm to 194 nm and captures solar cycle variability from just after maximum of Solar Cycle 23 through the long solar minimum and into the start of the rising phase of Solar Cycle 24. SEE has also captured spectral variability due to solar rotations and some solar flares. This paper will provide an overview of the SEE data, the advances in our understanding of solar EUV irradiance and its variability, and the utility of the data and results to the space weather community.

  14. Validation of the UARS solar ultraviolet irradiances: Comparison with the ATLAS 1 and 2 measurements

    Microsoft Academic Search

    T. N. Woods; D. K. Prinz; G. J. Rottman; P. C. Crane; R. P. Cebula; E. Hilsenrath; G. E. Brueckner; M. D. Andrews; O. R. White; M. E. VanHoosier; L. E. Floyd; L. C. Herring; B. G. Knapp; C. K. Pankratz; P. A. Reiser

    1996-01-01

    The measurements of the solar ultraviolet spectral irradiance made by the two Upper Atmosphere Research Satellite (UARS) solar instruments, Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) and SOLar STellar Irradiance Comparison Experiment (SOLSTICE), are compared with same-day measurements by two solar instruments on the shuttle ATmospheric Laboratory for Applications and Science (ATLAS) missions, ATLAS SUSIM and Shuttle Solar Backscatter Ultra Violet

  15. Solar irradiance modulation by active regions from 1969 through 1981

    Microsoft Academic Search

    Douglas V. Hoyt; J. A. Eddy

    1983-01-01

    Recent satellite measurements of the solar total irradiance (S) indicate that on time scales of days to months the solar constant varies by a few tenths of a percent. The predominant part of these variations can be explained by blocking of the upward solar flux by sunspots. The observations are consistent with current theoretical models of energy storage in which

  16. Solar resource assessment with a solar spectral irradiance meter

    NASA Astrophysics Data System (ADS)

    Tatsiankou, Viktar; Hinzer, Karin; Muron, Aaron; Haysom, Joan; Schriemer, Henry; Myrskog, Stefan

    2014-09-01

    The SSIM prototype was designed at the University of Ottawa as a cost-effective alternative to a field spectrora-diometer. The instrument was installed at the University of Ottawa's CPV testing facility in September, 2013, collecting the environmental and spectral data from October, 2013 to March, 2014. The SSIM's performance was compared against an ASD field spectroradiometer and an Eppley pyrheliometer during a six month study. It was observed that the SSIM can accurately reproduce the solar spectrum and the direct normal irradiance. The mean difference between the SSIM and the Eppley pyrheliometer was within ±1.5% for cloudless periods in October, 2013. However, bandpass filter degradation and moisture ingress limited the long term performance of the device.

  17. Anomalously low solar extreme-ultraviolet irradiance and thermospheric density during solar minimum

    Microsoft Academic Search

    Stanley C. Solomon; Thomas N. Woods; Leonid V. Didkovsky; John T. Emmert; Liying Qian

    2010-01-01

    Solar activity during 2007–2009 was very low, and during this protracted solar minimum period, the terrestrial thermosphere was cooler and lower in density than expected. Measurements from instruments on the SOHO and TIMED spacecraft, and by suborbital rocket flights, indicate that solar extreme-ultraviolet irradiance levels were lower than they were during the previous solar minimum. Analysis of atmospheric drag on

  18. Long-term reconstructions of total solar irradiance

    NASA Astrophysics Data System (ADS)

    Krivova, Natalie; Solanki, Sami K.; Dasi Espuig, Maria

    2012-07-01

    Solar irradiance is the main external driver of the Earth's climate, although its relative contribution compared to other internal and anthropogenic factors is not yet well determined. Variations of total solar irradiance have being measured for over three decades and are relatively well understood. Reconstructions of the irradiance into the past remain, however, rather uncertain. In particular, the magnitude of the secular change is highly debated. The reason is the lack of direct and well-sampled proxies of solar magnetic activity on time scales longer than a few decades. Reconstructions on time scales of centuries rely on sunspot observations available since 1610. Reconstructions on millennial time scales use concentrations of the cosmogenic isotopes in terrestrial archives. We will review long-term reconstructions of the solar irradiance using the SATIRE set of models, compare them with other recent models and discuss the remaining uncertainties.

  19. Effect of the total solar irradiance variations on solar-sail low-eccentricity orbits

    Microsoft Academic Search

    Giovanni Vulpetti

    2010-01-01

    Solar photon sailing is based on the radiation pressure of the total solar irradiance (TSI). This note analyzes the effects of the actual irradiance on low-eccentricity orbits as an introductory work to much more complex cases such as sailcraft-Mars rendezvous. Two special orbits are considered: (1) a circular warning orbit and (2) a transfer orbit between Earth and Mars. It

  20. Variations in solar Lyman alpha irradiance on short time scales

    NASA Technical Reports Server (NTRS)

    Pap, J. M.

    1992-01-01

    Variations in solar UV irradiance at Lyman alpha are studied on short time scales (from days to months) after removing the long-term changes over the solar cycle. The SME/Lyman alpha irradiance is estimated from various solar indices using linear regression analysis. In order to study the nonlinear effects, Lyman alpha irradiance is modeled with a 5th-degree polynomial as well. It is shown that the full-disk equivalent width of the He line at 1083 nm, which is used as a proxy for the plages and active network, can best reproduce the changes observed in Lyman alpha. Approximately 72 percent of the solar-activity-related changes in Lyman alpha irradiance arise from plages and the network. The network contribution is estimated by the correlation analysis to be about 19 percent. It is shown that significant variability remains in Lyman alpha irradiance, with periods around 300, 27, and 13.5d, which is not explained by the solar activity indices. It is shown that the nonlinear effects cannot account for a significant part of the unexplained variation in Lyman alpha irradiance. Therefore, additional events (e.g., large-scale motions and/or a systematic difference in the area and intensity of the plages and network observed in the lines of Ca-K, He 1083, and Lyman alpha) may explain the discrepancies found between the observed and estimated irradiance values.

  1. Total solar irradiance fluctuation effects on sailcraft-Mars rendezvous

    Microsoft Academic Search

    Giovanni Vulpetti

    2011-01-01

    This paper is the second one of a research line whereupon the variations of the total solar irradiance are explicitly included in a large high-precision computer code for sailcraft trajectory optimization. Sailcraft-Mars rendezvous has been chosen for studying such effects. It turns out that irradiance-fluctuation perturbations are large in this trajectory type.

  2. Open Surface Solar Irradiance Observations - A Challenge

    NASA Astrophysics Data System (ADS)

    Menard, Lionel; Nüst, Daniel; Jirka, Simon; Maso, Joan; Ranchin, Thierry; Wald, Lucien

    2015-04-01

    The newly started project ConnectinGEO funded by the European Commission aims at improving the understanding on which environmental observations are currently available in Europe and subsequently providing an informational basis to close gaps in diverse observation networks. The project complements supporting actions and networking activities with practical challenges to test and improve the procedures and methods for identifying observation data gaps, and to ensure viability in real world scenarios. We present a challenge on future concepts for building a data sharing portal for the solar energy industry as well as the state of the art in the domain. Decision makers and project developers of solar power plants have identified the Surface Solar Irradiance (SSI) and its components as an important factor for their business development. SSI observations are crucial in the process of selecting suitable locations for building new plants. Since in-situ pyranometric stations form a sparse network, the search for locations starts with global satellite data and is followed by the deployment of in-situ sensors in selected areas for at least one year. To form a convincing picture, answers must be sought in the conjunction of these EO systems, and although companies collecting SSI observations are willing to share this information, the means to exchange in-situ measurements across companies and between stakeholders in the market are still missing. We present a solution for interoperable exchange of SSI data comprising in-situ time-series observations as well as sensor descriptions based on practical experiences from other domains. More concretely, we will apply concepts and implementations of the Sensor Web Enablement (SWE) framework of the Open Geospatial Consortium (OGC). The work is based on an existing spatial data infrastructure (SDI), which currently comprises metadata, maps and coverage data, but no in-situ observations yet. This catalogue is already registered in the GEOSS Common Infrastructure (GCI). We describe the challenges and approach to introduce a suite of standards and best practices into the GEO Energy Societal Benefit Area for solar radiation measurements. Challenges range from spatio-temporal coverage across different scales and data quality to intellectual property rights and existing terminology. The approach includes means to share observations based on standardized data and metadata models and a user-friendly data exploration/management tool. The possibility to access and share data considerably improves the information base for strategic planning and control of new solar power resources. The platform will be integrated as a new component into the Webservice-Energy.org GEOSS Community Portal dedicated to Energy and Environment. The ability to provide users with visualisation and download features for in-situ measurements is seen as a key aspect to start engaging the energy community to share, release and integrate more in-situ measurements. This will put to the test the capacity of cooperation in the SSI community by introducing an unprecedented level of collaboration and eventually help to detect gaps in European earth observation networks. The presentation will be an opportunity to seek further collaboration partners and feedback by the community.

  3. Vacuum-ultraviolet instrumentation for solar irradiance and thermospheric airglow

    SciTech Connect

    Woods, T.N.; Rottman, G.J. (National Center for Atmospheric Research, Boulder, CO (United States). High Altitude Observatory); Bailey, S.M.; Solomon, S.C. (Univ. of Colorado, Boulder, CO (United States). Lab. for Atmospheric and Space Physics)

    1994-02-01

    A NASA sounding rocket experiment was developed to study the solar extreme-ultraviolet (EUV) spectral irradiance and its effect on the upper atmosphere. Both the solar flux and the terrestrial molecular nitrogen via the Lyman-Birge-Hopfield bands in the far-ultraviolet (FUV) region were measured remotely from a sounding rocket on October 27, 1992. The rocket experiments also includes EUV instruments from Boston University, but only the National Center for Atmospheric Research's (NCAR)/University of Colorado's (CU) four solar instruments and one airglow instrument are discussed. The primary solar EUV instrument is a 0.25-m Rowland circle EUV spectrograph that has flown on three rockets since 1988 measuring the solar spectral irradiance from 30 to 110 nm with 0.2-nm resolution. Another solar irradiance instrument is an array of six silicon soft x-ray (XUV) photodiodes, each having different metallic filters coated directly on the photodiodes. The other solar irradiance instrument is a silicon avalanche photodiode coupled with pulse height analyzer electronics. The fourth solar instrument is a XUV imager that images the sun at 17.5 nm with a spatial resolution of 20 arc sec. The airglow spectrograph measures the terrestrial FUV airglow emissions along the horizon from 125 to 160 nm with 0.2-nm spectral resolution.

  4. Utilization of extraterrestrial resources: the US case

    SciTech Connect

    Kraniou, D.J.

    1984-01-01

    This is a policy oriented work that examines the possibilities of utilization of extraterrestrial space resources by the United States public and private sectors alike. Specific emphasis is placed on the resources of space located up to the geosynchronous orbit. Resources examined include the space vacuum, the infinitesimally small gravitational forces, the extraterrestrial solar energy, and the geosynchronous orbit. The impact of extraterrestrial resources is analyzed vis-a-vis the United States security, energy, economic, technological, and political (domestic, international) concerns. Scenarios to promote the efficient utilization of these resources are considered, and cost-benefit analyses are developed to examine the degree of justification of these undertakings.

  5. Improved accuracy for low-cost solar irradiance sensors

    SciTech Connect

    King, D.L.; Boyson, W.E.; Hansen, B.R.

    1997-12-31

    Accurate measurements of broadband (full spectrum) solar irradiance are fundamental to the successful implementation of solar power systems, both photovoltaic and solar thermal. Historically, acceptable measurement accuracy has been achieved using expensive thermopile-based pyranometers and pyrheliometers. The measurement limitations and sensitivities of these expensive radiometers are a topic that has been addressed elsewhere. This paper demonstrates how to achieve acceptable accuracy ({+-}3) in irradiance measurements using photodiodes or photovoltaic cells as sensors, and in addition to low-cost, have several operational advantages.

  6. The solar spectral irradiances from x ray to radio wavelengths

    NASA Technical Reports Server (NTRS)

    White, O. R.

    1993-01-01

    Sources of new measurements of the solar EUV, UV, and visible spectrum are presented together with discussion of formation of the solar spectrum as a problem in stellar atmospheres. Agreement between the data and a modern synthetic spectrum shows that observed radiative variability is a minor perturbation on a photosphere in radiative equilibrium and local thermodynamic equilibrium (LTE). Newly observed solar variability in 1992 defines a magnetic episode on the Sun closely associated with changes in both spectral irradiances and the total irradiance. This episode offers the opportunity to track the relationship between radiation and magnetic flux evolution.

  7. LISIRD: Where to go for Solar Irradiance Data

    NASA Astrophysics Data System (ADS)

    Wilson, A.; Pankratz, C. K.; Lindholm, D. M.; Snow, M.; Knapp, B.; Woodraska, D.; Templeman, B.; Woods, T.; Eparvier, F.; Fontenla, J.; Harder, J.; Bill, M.

    2008-12-01

    LASP, the Laboratory for Atmospheric and Space Physics, has been providing web access to solar irradiance measurements, reference spectra, composites and model data covering the solar spectrum from .1 to 2400 nm through LISIRD, the LASP Interactive Solar IRradiance Datacenter. No single instrument can measure the solar spectral irradiance from X-rays to the IR, but the ensemble of LASP instruments can. LISIRD uses a single interface to provide easy, logical access to a variety of mission data, merged in time and wavelength. Daily space weather measurements are available, including total solar irradiance (TSI), Lyman Alpha (121 nm), Magnesium II Index (280 nm), He II (30.4 nm), FE XVI (33.5 nm), and the FUV continuum (145 to 165 nm). More recently, LISIRD has recently added the Whole Heliosphere Interval (WHI) Solar Irradiance time series, which provides a quiet sun reference spectra for the period of April 10-16 of 2008. LISIRD also recently added a composite solar spectral irradiance product over the range of 120 to 400 nm for the time period from November 8, 1978 to August 1, 2005. This product, created by Mathew Deland at SSAI, merges data from six different satellites into a single SSI product. And, we are currently adding a time series for daily solar spectral irradiance from 1950 to 2006, created by Judith Lean of the Naval Research Lab. This product adjusts observed irradiance for a given wavelength with parameters that represent known sources of variability at that wavelength. LISIRD remains committed to improving data access in a variety of ways. We are planning and developing a means for the broader community of scientists to easily determine data availability for a particular date range without having to know mission or instrument details. Improved data subsetting will allow users to request only the time range or spectra that users need, making data management generally easier. We expect to continue to enhance our data offerings. Future vision for LISIRD also includes integration of improved data visualization and analysis tools. We welcome contributions from solar science community members who wish to share data and tools they have developed. We also expect to integrate LISIRD with the Virtual Solar Observatory (VSO) and other relevant Virtual Observatories (VOs) for a more integrated and complete user experience. We are actively seeking input and feedback to improve LISIRD from interested users of this data. Towards this end we have provided a survey at our website and to AGU attendees. Those who use LISIRD and provide feedback will have the opportunity to help steer LISIRD development. Let us know what you would like to see and we will try to make it happen!

  8. Forecast Solar Irradiance Variability on Multiple Time Scales

    NASA Astrophysics Data System (ADS)

    Tobiska, W.; Schatten, K.; Pryor, W.; Bouwer, D.; Detman, T.; Woods, T.; Pankratz, C.; Eparvier, F. G.; Viereck, R.; Puga, L.

    2001-12-01

    We report on research that is improving current solar spectral irradiance forecasting capabilities. In particular, the portion of the solar spectrum chosen is that applicable to operational atmospheric density specifications related to low-Earth orbiting satellites. There are six time scales of solar variability for which we are developing forecast algorithms. These include 1-72 hour time scales associated with large flares, 3-14 day Earth-facing solar disk irradiances, 14-28 day solar far side events, 1-6 month active region evolution, 1/2-11 year solar cycle variability, and 1-5 solar cycle climatological specification. Many current algorithms use the first-order assumption of solar irradiance persistence over specific time scales. The basis for forecasting on each of these time derives from a different source. For example, the nowcast, current 24-hour period uses the method of Viereck et al. (2001) where EUV (proxy) = 0.6 MgII (daily) + 0.4 MgII (29-day avg). The 72-hour forecast is generated with an autoregressive technique to determine the trend of the next 3 days. The 14-day forecast simply uses the previous data from 14-days ago to the present epoch. The 28-day forecast uses the previous 28-days of data convolved with a triangular function to reduce noise. The 6-month forecast uses the previous 6-months of data convolved with a 30-day wide triangular function. The 11-year forecast has used the previous 11-years of data similarly convolved. The 55-year forecast uses the mean value of the previous 5 solar cycles. Improvements to these algorithms are demonstrated that will reduce the uncertainty and quantify the variability in each forecast time scale, as these algorithms are used in forecasting solar irradiances for space system operations. Viereck , R., et al., Geophys. Res. Lett., 28, 1343-1346, 2001.

  9. Classification of extraterrestrial civilizations

    NASA Astrophysics Data System (ADS)

    Tang, Tong B.; Chang, Grace

    1991-06-01

    A scheme of classification of extraterrestrial intelligence (ETI) communities based on the scope of energy accessible to the civilization in question is proposed as an alternative to the Kardeshev (1964) scheme that includes three types of civilization, as determined by their levels of energy expenditure. The proposed scheme includes six classes: (1) a civilization that runs essentially on energy exerted by individual beings or by domesticated lower life forms, (2) harnessing of natural sources on planetary surface with artificial constructions, like water wheels and wind sails, (3) energy from fossils and fissionable isotopes, mined beneath the planet surface, (4) exploitation of nuclear fusion on a large scale, whether on the planet, in space, or from primary solar energy, (5) extensive use of antimatter for energy storage, and (6) energy from spacetime, perhaps via the action of naked singularities.

  10. Extraterrestrial materials processing

    NASA Technical Reports Server (NTRS)

    Steurer, W. H.

    1982-01-01

    The first year results of a multi-year study of processing extraterrestrial materials for use in space are summarized. Theoretically, there are potential major advantages to be derived from the use of such materials for future space endeavors. The types of known or postulated starting raw materials are described including silicate-rich mixed oxides on the Moon, some asteroids and Mars; free metals in some asteroids and in small quantities in the lunar soil; and probably volatiles like water and CO2 on Mars and some asteroids. Candidate processes for space materials are likely to be significantly different from their terrestrial counterparts largely because of: absence of atmosphere; lack of of readily available working fluids; low- or micro-gravity; no carbon-based fuels; readily available solar energy; and severe constraints on manned intervention. The extraction of metals and oxygen from lunar material by magma electrolysis or by vapor/ion phase separation appears practical.

  11. 1/f noise in the UV solar spectral irradiance

    NASA Astrophysics Data System (ADS)

    Varotsos, Costas A.; Melnikova, Irina; Efstathiou, Maria N.; Tzanis, Chris

    2013-02-01

    The investigation of the intrinsic properties of the solar spectral irradiance as a function of the ultraviolet (UV) wavelength is attempted by exploiting rare observations performed at the Villard St. Pancrace station of the Lille University of Sciences and Technology ranging from 278 to 400 nm with a step of 0.05 nm every half an hour from nearly sunrise to sunset. To achieve this goal, the modern method of the detrended fluctuation analysis was applied on the solar spectral irradiance values versus wavelength. This analysis revealed that the solar incident flux at the top of the atmosphere and the solar spectral irradiance at the ground during two overcast sky days fluctuate with the UV wavelength exhibiting persistent long-range power-law behavior. More interestingly, the exponent of the power-law relationship between the fluctuations of the solar spectral irradiance versus UV wavelength at both the top of the atmosphere and the ground is consistently close to unity (of 1/f-type) throughout the day. This 1/f behavior has been detected in many complex dynamical systems, but despite much effort to derive a theory for its widespread occurrence in nature, it remains unexplained so far. According to the above-mentioned findings we speculate that the 1/f property of the incident solar UV flux at the top of the atmosphere could probably drive both the 1/f behavior depicted in the atmospheric components and the solar UV irradiance at the Earth's surface. The latter could influence the UV-sensitive biological ecosystems, giving rise to a 1/f-type variability in the biosphere, which has already been proven by recent observational data. We finally propose that Wien approximation could be multiplied by a 1/f function of wavelength (e.g., of the type of the fractional Brownian motion) in order to reproduce the aforementioned 1/f feature of the solar UV flux.

  12. The extraterrestrial UV-background and the nearby interstellar medium

    Microsoft Academic Search

    H. J. Fahr

    1974-01-01

    Recent measurements of the extraterrestrial UV- and EUV-radiation, and the various theoretical approaches used in explaining the measured features of these radiations are reviewed. Whereas the structures and intensities of extraterrestrial EUV-radiation are essentially undetermined up to now, the observations of the extraterrestrial UV-sky give a clear indication of the existence of neutral interstellar hydrogen within the solar system.

  13. Vacuum-ultraviolet instrumentation for solar irradiance and thermospheric airglow

    NASA Astrophysics Data System (ADS)

    Woods, Thomas N.; Rottman, Gary J.; Bailey, Scott M.; Solomon, Stanley C.

    1994-02-01

    A NASA sounding rocket experiment was developed to study the solar extreme-ultraviolet (EUV) spectral irradiance and its effect on the upper atmosphere. Both the solar flux and the terrestrial molecular nitrogen via the Lyman-Birge-Hopfield bands in the far-ultraviolet (FUV) region were measured remotely from a sounding rocket on October 27, 1992. The rocket experiment also includes EUV instruments from Boston University, but only the National Center for Atmospheric Research's (NCAR)/University of Colorado's (CU) four solar instruments and one airglow instrument are discussed. The primary solar EUV instrument is a 0.25-m Rowland circle EUV spectrograph that has flown on three rockets since 1988 measuring the solar spectral irradiance from 30 to 110 nm with 0.2-nm resolution. Another solar irradiance instrument is an array of six silicon soft x-ray (XUV) photodiodes, each having different metallic filters coated directly on the photodiodes. This photodiode system provides a spectral coverage from 0.1 to 80 nm with approximately 15-nm resolution. The other solar irradiance instrument is a silicon avalanche photodiode coupled with pulse height analyzer electronics. This avalanche photodiode package measures the XUV photon energy, providing a solar spectrum from 50 to 12,400 eV (25 to 0.1 nm) with an energy resolution of about 50 eV. The fourth solar instrument is an XUV imager that images the sun at 17.5 nm with a spatial resolution of 20 arc sec. The airglow spectrograph measures the terrestrial FUV airglow emissions along the horizon from 125 to 160 nm with 0.2-nm spectral resolution. The photon-counting CODACON detectors are used for three of these instruments and consist of coded arrays of anodes behind microchannel plates.

  14. Proton irradiated heteroepitaxial InP solar cells

    Microsoft Academic Search

    I. Weinberg; R. K. Jain; C. K. Swartza; H. B. Curtis; D. J. Brinker; C. Vargas-Aburtob; P. J. Drevinsky

    1993-01-01

    Heteroepitaxial InP solar cells, processed using GaAs substrates, were proton irradiated over the energy range from 0.2 to 10 MeV. Results for carrier removal, cell performance and minority carrier diffusion length were found to be separable into either dislocation dominated or energy dependent categories. High dislocation densities were dominant in determining low pre-irradiation minority carrier diffusion lengths and cell efficiencies.

  15. Measuring and modeling solar irradiance on vertical surfaces

    SciTech Connect

    Maxwell, E.L.; Stoffel, T.L.; Bird, R.E.

    1986-07-01

    This report presents the first evaluations of 5 algorithms for converting global horizontal and direct normal solar irradiance components to global irradiance on tilted surfaces using measurements from the Solar Radiation Research Laboratory (SRRL) at SERI. High resolution (15-min) measurements from 8 thermopile radiometers oriented vertically in the 4 cardinal directions were available for a 169-day period ending 31 December 1984. Concurrent measurements of global horizontal and direct normal solar irradiance components were also used. The pyranometers used were intercompared on horizontal, north-facing, and south-facing vertical orientations. The conversion algorithms each attempt to account for the very complex atmospheric interactions with incoming solar radiation. The sky and ground radiance contributions to tilted surface are assumed to be isotropic, anisotropic, or a combination of the two depending on the algorithm. Results from the analysis of measurements on vertical surfaces for 22 July through 4 September indicate a general overestimate (18% to 46.5%) of solar irradiance on north-facing surfaces by all 5 of the algorithms. The best agreement with measured data was demonstrated for south-facing surfaces where all but one algorithm were within the present measurement by as much as 23% of the observed 15-min data.

  16. Prediction of global solar irradiance based on time series analysis: Application to solar thermal power plants energy production planning

    Microsoft Academic Search

    Luis Martin; Ruth Marchante; Marco Cony; Luis F. Zarzalejo; Jesus Polo; Ana Navarro

    2010-01-01

    Due to strong increase of solar power generation, the predictions of incoming solar energy are acquiring more importance. Photovoltaic and solar thermal are the main sources of electricity generation from solar energy. In the case of solar thermal energy plants with storage energy system, its management and operation need reliable predictions of solar irradiance with the same temporal resolution as

  17. The Sun and Climate Solar Irradiance

    E-print Network

    Walter, Frederick M.

    the surface of the Earth, this is 2 x 1024 erg/s, or 2 x 1017 watts (100 million gigawatts). This energy input keeps the Earth warm. If the solar constant were To change, so would the Earth's temperature. Solar is called the "Little Ice Age". ·Sunspot numbers are the highest they have been since before 1750. #12;Does

  18. The solar spectral irradiance 1200-3184 a near solar maximum, 15 July 1980

    NASA Technical Reports Server (NTRS)

    Mount, G. H.; Rottman, G. J.

    1980-01-01

    Full disk solar spectral irradiances near solar maximum were obtained in the spectral range 1200 to 3184 A at a spectral resolution of approximately 1 A from rocket observations above White Sands Missile Range. Comparison with measurements made during solar minimum confirm a large increase at solar maximum in the solar irradiance near 1200 A with no change within the measurement errors near 2000 A. Irradiances in the range 1900 to 2100 A are in excellent agreement with previous measurements, and those in the 2100 to 2500 A range are lower than separate previous results in this range. Agreement is found with previous values 2500 to 2900 A A, and then fall below those values 2900 to 3184 A.

  19. UV solar irradiance in observations and the NRLSSI and SATIRE-S models

    E-print Network

    Yeo, K L; Krivova, N A; Solanki, S K; Unruh, Y C; Morrill, J

    2015-01-01

    Total solar irradiance and UV spectral solar irradiance have been monitored since 1978 through a succession of space missions. This is accompanied by the development of models aimed at replicating solar irradiance by relating the variability to solar magnetic activity. The NRLSSI and SATIRE-S models provide the most comprehensive reconstructions of total and spectral solar irradiance over the period of satellite observation currently available. There is persistent controversy between the various measurements and models in terms of the wavelength dependence of the variation over the solar cycle, with repercussions on our understanding of the influence of UV solar irradiance variability on the stratosphere. We review the measurement and modelling of UV solar irradiance variability over the period of satellite observation. The SATIRE-S reconstruction is consistent with spectral solar irradiance observations where they are reliable. It is also supported by an independent, empirical reconstruction of UV spectral s...

  20. Standard Solar Spectra: Air Mass 1.5

    NSDL National Science Digital Library

    Renewable Resource Data Center (RReDC)

    This site presents information about American Society for Testing and Materials (ASTM) Standard Extraterrestrial Spectrum Reference E-490-00. Information is available in two tables, one listing the Solar Constant in alternative units, and the other listing solar irradiance at the planets. There are also links to related resources.

  1. How the inclination of Earth's orbit affects incoming solar irradiance

    NASA Astrophysics Data System (ADS)

    Vieira, L. E. A.; Norton, A.; Dudok de Wit, T.; Kretzschmar, M.; Schmidt, G. A.; Cheung, M. C. M.

    2012-08-01

    The variability in solar irradiance, the main external energy source of the Earth's system, must be critically studied in order to place the effects of human-driven climate change into perspective and allow plausible predictions of the evolution of climate. Accurate measurements of total solar irradiance (TSI) variability by instruments onboard space platforms during the last three solar cycles indicate changes of approximately 0.1% over the sunspot cycle. Physics-based models also suggest variations of the same magnitude on centennial to millennia time-scales. Additionally, long-term changes in Earth's orbit modulate the solar irradiance reaching the top of the atmosphere. Variations of orbital inclination in relation to the Sun's equator could potentially impact incoming solar irradiance as a result of the anisotropy of the distribution of active regions. Due to a lack of quantitative estimates, this effect has never been assessed. Here, we show that although observers with different orbital inclinations experience various levels of irradiance, modulations in TSI are not sufficient to drive observed 100 kyr climate variations. Based on our model we find that, due to orbital inclination alone, the maximum change in the average TSI over timescales of kyrs is ˜0.003 Wm-2, much smaller than the ˜1.5 Wm-2 annually integrated change related to orbital eccentricity variations, or the 1-8 Wm-2 variability due to solar magnetic activity. Here, we stress that out-of-ecliptic measurements are needed in order to constrain models for the long-term evolution of TSI and its impact on climate.

  2. Laboratory for Extraterrestrial Physics

    NASA Technical Reports Server (NTRS)

    Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    The NASA Goddard Space Flight Center (GSFC) Laboratory for Extraterrestrial Physics (LEP) performs experimental and theoretical research on the heliosphere, the interstellar medium, and the magnetospheres and upper atmospheres of the planets, including Earth. LEP space scientists investigate the structure and dynamics of the magnetospheres of the planets including Earth. Their research programs encompass the magnetic fields intrinsic to many planetary bodies as well as their charged-particle environments and plasma-wave emissions. The LEP also conducts research into the nature of planetary ionospheres and their coupling to both the upper atmospheres and their magnetospheres. Finally, the LEP carries out a broad-based research program in heliospheric physics covering the origins of the solar wind, its propagation outward through the solar system all the way to its termination where it encounters the local interstellar medium. Special emphasis is placed on the study of solar coronal mass ejections (CME's), shock waves, and the structure and properties of the fast and slow solar wind. LEP planetary scientists study the chemistry and physics of planetary stratospheres and tropospheres and of solar system bodies including meteorites, asteroids, comets, and planets. The LEP conducts a focused program in astronomy, particularly in the infrared and in short as well as very long radio wavelengths. We also perform an extensive program of laboratory research, including spectroscopy and physical chemistry related to astronomical objects. The Laboratory proposes, develops, fabricates, and integrates experiments on Earth-orbiting, planetary, and heliospheric spacecraft to measure the characteristics of planetary atmospheres and magnetic fields, and electromagnetic fields and plasmas in space. We design and develop spectrometric instrumentation for continuum and spectral line observations in the x-ray, gamma-ray, infrared, and radio regimes; these are flown on spacecraft to study the interplanetary medium, asteroids, comets, and planets. Suborbital sounding rockets and groundbased observing platforms form an integral part of these research activities. This report covers the period from approximately October 1999 through September 2000.

  3. Instrument Technologies for the Detection of Extraterrestrial Interstellar Robotic Probes

    Microsoft Academic Search

    Scot L. Stride

    2001-01-01

    In the continuing endeavor to detect evidence of ETI (Extraterrestrial Intelligence) in the solar neighborhood, instrument technologies now exist that allow the formation of a scientific method to carry out a search for interstellar robotic probes of possible extraterrestrial origin. The range of currently observable probe features\\/manifestations will be shown and how they influence search space, instrument selection and deployment.

  4. Seed germination of Stenocereus thurberi (Cactaceae) under different solar irradiation levels

    Microsoft Academic Search

    H Nolasco; F Vega-Villasante; A Diaz-Rondero

    1997-01-01

    Germination ofStenocereus thurberiseeds was evaluated under different conditions of solar irradiation and humidity. Seed germination increased under higher humidity and low solar irradiation which provided cooler temperatures and higher water availability. Seedlings were also greener and more turgid under these conditions. Increased solar irradiation reduced seed germination and decreased seedling size and water content. The results of this study support

  5. Uncertainty of measurements of spectral solar UV irradiance

    Microsoft Academic Search

    G. Bernhard; G. Seckmeyer

    1999-01-01

    Most investigations on the nature and effects of solar ultraviolet (UV) radiation at the Earth's surface require measurements of high accuracy combined with well-defined procedures to assess their quality. Here we present a general evaluation of all relevant errors and uncertainties associated with measurements of spectral global irradiance in the UV. The uncertainties are quantified in terms of dependence of

  6. Simulation of nonuniform irradiance in multijunction IIIV solar cells

    Microsoft Academic Search

    J. M. Olson

    2010-01-01

    Optics for high concentration photovoltaics often delivers a non-uniform irradiance to the cell. This can be a problem for tunnel-junction interconnected (TJIC) IIIV multijunction solar cells if the resulting local photocurrent exceeds the peak tunneling current density. Current spreading in the vicinity of the tunnel junction can mitigate this effect. We use commercial software to simulate current spreading in a

  7. Aircraft observations of the solar ultraviolet irradiance throughout the troposphere

    Microsoft Academic Search

    C. Varotsos; D. Alexandris; G. Chronopoulos; C. Tzanis

    2001-01-01

    Observations of the biological effective solar ultraviolet irradiance, made by instrumentation flown on a Falcon aircraft over the entire Greek area, from the sea up to the tropopause level, obtained in the frame of the Radiation Field in the Troposphere-Scientific Training and Access to Aircraft for Atmospheric Research Throughout Europe project, are presented to discuss among others its altitude dependence.

  8. Stable Isotope Variations in Extraterrestrial Materials Kevin D. McKeegan 1

    E-print Network

    1 Stable Isotope Variations in Extraterrestrial Materials by Kevin D. McKeegan 1 and Laurie A the isotopic records of extraterrestrial materials range widely in environmental conditions from very high in the solar nebula to lower temperature fluid-rock interactions in asteroids and planets. In extraterrestrial

  9. 1978-1988 Total Solar Irradiance (TSI) Variability Trends

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Priestley, Kory J.; Wilson, Robert S.; Al-Hajjah, Aiman; Paden, Jack; Pandey, Dhirendra K.; Thomas, Susan

    1999-01-01

    Total solar irradiance (TSI), normalized to the mean earth-sun distance, is analyzed to assess long-term solar variability which may affect climate. TSI data sets are reviewed primarily from the 1984-1999 Earth Radiation Budgets Satellite (ERBS), 1978-1993 Nimbus7, 1980-1989 Solar Maximum Mission (SMM), 19911998 Upper Atmospheric Research Satellite (UARS), and 1996-1998 Solar and Heliospheric Observatory (SOHO)/ Variability of solar IRradiance and Gravity Oscillations (VIRGO) Spacecraft missions. The data sets indicate that 1365 W/sq m [Watts per meter square] is the most likely TSI amplitude at minimum solar magnetic activity as indicated by minimum sunspot numbers. The TSI long-term variability component was found to vary with a period of approximately 10 years and with an amplitude of 2 W/sq m. An empirical TSI fit model, based upon 10.7-cm solar radio fluxes and prompt photometric sunspot indices, was used to characterize TSI variability. Comparisons among TSI measurements and empirical fit trends are reviewed as well as inconsistencies among current spacecraft TSI data set trends. The 1996-1998, SOHO/VIRGO measurement indicate stronger TSI increasing trends than those suggested by the corresponding ERBS and UARS measurement and by the empirical model fit. 1978-1999 TSI data sets are analyzed to identify the probable existence of another long-term TSI variability component.

  10. Irradiance optimization of outdoor microalgal cultures using solar tracked photobioreactors.

    PubMed

    Hindersin, Stefan; Leupold, Marco; Kerner, Martin; Hanelt, Dieter

    2013-03-01

    Photosynthetic activity and temperature regulation of microalgal cultures (Chlorella vulgaris and Scenedesmus obliquus) under different irradiances controlled by a solar tracker and different cell densities were studied in outdoor flat panel photobioreactors. An automated process control unit regulated light and temperature as well as pH value and nutrient concentration in the culture medium. CO2 was supplied using flue gas from an attached combined block heat and power station. Photosynthetic activity was determined by pulse amplitude modulation fluorometry. Compared to the horizontal irradiance of 55 mol photons m(-2) d(-1) on a clear day, the solar tracked photobioreactors enabled a decrease and increase in the overall light absorption from 19 mol photons m(-2) d(-1) (by rotation out of direct irradiance) to 79 mol photons m(-2) d(-1) (following the position of the sun). At biomass concentrations below 1.1 g cell dry weight (CDW) L(-1), photoinhibition of about 35 % occurred at irradiances of ?1,000 ?mol photons m(-2) s(-1) photosynthetic active radiation (PAR). Using solar tracked photobioreactors, photoinhibition can be reduced and at optimum biomass concentration (?2.3 g CDW L(-1)), the culture was irradiated up to 2,000 ?mol photons m(-2) s(-1) to overcome light limitation with biomass yields of 0.7 g CDW mol photons(-1) and high photosynthetic activities indicated by an effective quantum yield of 0.68 and a maximum quantum yield of 0.80 (F v/F m). Overheating due to high irradiance was avoided by turning the PBR out of the sun or using a cooling system, which maintained the temperature close to the species-specific temperature optima. PMID:22847362

  11. Vacuum ultraviolet instrumentation for solar irradiance and thermospheric airglow

    NASA Technical Reports Server (NTRS)

    Woods, Thomas N.; Rottman, Gary J.; Bailey, Scott M.; Solomon, Stanley C.

    1993-01-01

    A NASA sounding rocket experiment was developed to study the solar extreme ultraviolet (EUV) spectral irradiance and its effect on the upper atmosphere. Both the solar flux and the terrestrial molecular nitrogen via the Lyman-Birge-Hopfield bands in the far ultraviolet (FUV) were measured remotely from a sounding rocket on October 27, 1992. The rocket experiment also includes EUV instruments from Boston University (Supriya Chakrabarti), but only the National Center for Atmospheric Research (NCAR)/University of Colorado (CU) four solar instruments and one airglow instrument are discussed here. The primary solar EUV instrument is a 1/4 meter Rowland circle EUV spectrograph which has flown on three rockets since 1988 measuring the solar spectral irradiance from 30 to 110 nm with 0.2 nm resolution. Another solar irradiance instrument is an array of six silicon XUV photodiodes, each having different metallic filters coated directly on the photodiodes. This photodiode system provides a spectral coverage from 0.1 to 80 nm with about 15 nm resolution. The other solar irradiance instrument is a silicon avalanche photodiode coupled with pulse height analyzer electronics. This avalanche photodiode package measures the XUV photon energy providing a solar spectrum from 50 to 12,400 eV (25 to 0.1 nm) with an energy resolution of about 50 eV. The fourth solar instrument is an XUV imager that images the sun at 17.5 nm with a spatial resolution of 20 arc-seconds. The airglow spectrograph measures the terrestrial FUV airglow emissions along the horizon from 125 to 160 nm with 0.2 nm spectral resolution. The photon-counting CODACON detectors are used for three of these instruments and consist of coded arrays of anodes behind microchannel plates. The one-dimensional and two-dimensional CODACON detectors were developed at CU by Dr. George Lawrence. The pre-flight and post-flight photometric calibrations were performed at our calibration laboratory and at the Synchrotron Ultraviolet Radiation Facility (SURF) at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland.

  12. Vacuum ultraviolet instrumentation for solar irradiance and thermospheric airglow

    NASA Astrophysics Data System (ADS)

    Woods, Thomas N.; Rottman, Gary J.; Bailey, Scott M.; Solomon, Stanley C.

    1993-08-01

    A NASA sounding rocket experiment was developed to study the solar extreme ultraviolet (EUV) spectral irradiance and its effect on the upper atmosphere. Both the solar flux and the terrestrial molecular nitrogen via the Lyman-Birge-Hopfield bands in the far ultraviolet (FUV) were measured remotely from a sounding rocket on October 27, 1992. The rocket experiment also includes EUV instruments from Boston University (Supriya Chakrabarti), but only the National Center for Atmospheric Research (NCAR)/University of Colorado (CU) four solar instruments and one airglow instrument are discussed here. The primary solar EUV instrument is a 1/4 meter Rowland circle EUV spectrograph which has flown on three rockets since 1988 measuring the solar spectral irradiance from 30 to 110 nm with 0.2 nm resolution. Another solar irradiance instrument is an array of six silicon XUV photodiodes, each having different metallic filters coated directly on the photodiodes. This photodiode system provides a spectral coverage from 0.1 to 80 nm with about 15 nm resolution. The other solar irradiance instrument is a silicon avalanche photodiode coupled with pulse height analyzer electronics. This avalanche photodiode package measures the XUV photon energy providing a solar spectrum from 50 to 12,400 eV (25 to 0.1 nm) with an energy resolution of about 50 eV. The fourth solar instrument is an XUV imager that images the sun at 17.5 nm with a spatial resolution of 20 arc-seconds. The airglow spectrograph measures the terrestrial FUV airglow emissions along the horizon from 125 to 160 nm with 0.2 nm spectral resolution. The photon-counting CODACON detectors are used for three of these instruments and consist of coded arrays of anodes behind microchannel plates. The one-dimensional and two-dimensional CODACON detectors were developed at CU by Dr. George Lawrence. The pre-flight and post-flight photometric calibrations were performed at our calibration laboratory and at the Synchrotron Ultraviolet Radiation Facility (SURF) at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland.

  13. Effect of solar irradiation on extracellular enzymes of Aeromonas proteolytica

    NASA Technical Reports Server (NTRS)

    Foster, B. G.

    1973-01-01

    The bacterium Aeromonas proteolytica was selected for studying the effects of solar irradiation on extracellular enzymes because it produces an endopeptidase that is capable of degrading proteins and a hemolysin that is active in lysing human erythrocytes. Possible alterations in the rate of enzyme production in response to the test conditions are currently underway and are not available for this preliminary report. Completed viability studies are indicative that little difference exists among the survival curves derived for cells exposed to various components of ultraviolet irradiation in space.

  14. Electron irradiation effects in epitaxial InP solar cells

    NASA Technical Reports Server (NTRS)

    Pearsall, N. M.; Robson, N.; Sambell, A. J.; Anspaugh, B.; Cross, T. A.

    1991-01-01

    Performance data for InP-based solar cells after irradiation with 1-MeV electrons up to a fluence of 1 x 1016 e/cm2 are presented. Three InP cell structures are considered. Two of these have epitaxially grown active regions, these being a homojunction design and in ITO/InP structure. These are compared with ITO/InP cells without the epitaxial base region. The cell parameter variations, the influence of illumination during irradiation, and the effect on cell spectral response and capacitance measurements are discussed. Substantial performance recovery after thermal annealing at 90 C is reported.

  15. Properties of solar gravity mode signals in total irradiance observations

    SciTech Connect

    Kroll, R.J.; Chen, J.; Hill, H.A.

    1988-01-01

    Further evidence has been found that a significant fraction of the gravity mode power density in the total irradiance observations appears in sidebands of classified eigenfrequencies. These sidebands whose amplitudes vary from year to year are interpreted as harmonics of the rotational frequencies of the nonuniform solar surface. These findings are for non axisymmetric modes and corroborate the findings of Kroll, Hill and Chen for axisymmetric modes. It is demonstrated the the generation of the sidebands lifts the usual restriction on the parity of the eigenfunctions for modes detectable in total irradiance observations. 14 refs.

  16. Photometric measurements of solar irradiance variations due to sunspots

    NASA Technical Reports Server (NTRS)

    Chapman, G. A.; Herzog, A. D.; Laico, D. E.; Lawrence, J. K.; Templer, M. S.

    1989-01-01

    A photometric telescope constructed to obtain photometric sunspot areas and deficits on a daily basis is described. Data from this Cartesian full disk telescope (CFDT) are analyzed with attention given to the period between June 4 and June 17, 1985 because of the availability of overlapping sunspot area and irradiance deficit data from high-resolution digital spectroheliograms made with the San Fernando Observatory 28 cm vacuum solar telescope and spectroheliograph. The CFDT sunspot deficits suggest a substantial irradiance contribution from faculae and active region plage.

  17. Proton irradiation damage in GaAs single crystals examined for solar cells

    Microsoft Academic Search

    Masafumi Yamaguchi; Akio Yamamoto; Atsushi Shibukawa

    1983-01-01

    In this study, high-energy proton (0.5-2 MeV) irradiation damage in GaAs solar cells and single crystals was compared with Co-60 gamma-ray irradiation damage. The minority carrier diffusion length in proton-irradiated GaAs single crystals can be evaluated from the photovoltaic effect of solar cells. The damage rate in GaAs due to proton irradiation equivalent to that due to Co-60 gamma-ray irradiation

  18. Method to Calculate Uncertainty Estimate of Measuring Shortwave Solar Irradiance using Thermopile and Semiconductor Solar Radiometers

    SciTech Connect

    Reda, I.

    2011-07-01

    The uncertainty of measuring solar irradiance is fundamentally important for solar energy and atmospheric science applications. Without an uncertainty statement, the quality of a result, model, or testing method cannot be quantified, the chain of traceability is broken, and confidence cannot be maintained in the measurement. Measurement results are incomplete and meaningless without a statement of the estimated uncertainty with traceability to the International System of Units (SI) or to another internationally recognized standard. This report explains how to use International Guidelines of Uncertainty in Measurement (GUM) to calculate such uncertainty. The report also shows that without appropriate corrections to solar measuring instruments (solar radiometers), the uncertainty of measuring shortwave solar irradiance can exceed 4% using present state-of-the-art pyranometers and 2.7% using present state-of-the-art pyrheliometers. Finally, the report demonstrates that by applying the appropriate corrections, uncertainties may be reduced by at least 50%. The uncertainties, with or without the appropriate corrections might not be compatible with the needs of solar energy and atmospheric science applications; yet, this report may shed some light on the sources of uncertainties and the means to reduce overall uncertainty in measuring solar irradiance.

  19. Investigation of Solar about 5-Month Cycle in Human Circulating Melatonin: Signature of Weather in Extraterrestrial Space?

    NASA Astrophysics Data System (ADS)

    Cornélissen, G.; Tarquini, R.; Perfetto, F.; Otsuka, K.; Gigolashvili, M.; Halberg, F.

    2009-12-01

    Melatonin, produced mainly in the pineal and the gut, is often thought of as the "dark hormone" as its concentration in the circulation is high during darkness and low during light in diurnally- and nocturnally-active mammals in health. About-daily and about-yearly periodicities can thus be anticipated to characterize melatonin, matching the two major photic environmental cycles. Non-photic solar influences have also been observed, melatonin being depressed in association with magnetic storms. While less stable than the daily and yearly changes, non-photic solar dynamics also undergo various periodicities. Among them is an about 0.42-year (about 5-month or 154-day) cycle, reported by several physicists in relation to Zürich relative sunspot numbers and to solar flares. This putative signature of solar activity was found in the incidence pattern of sudden cardiac death in Minnesota, USA, among other geographic locations. A cycle with a period of about 0.42 year is here reported in data on circulating melatonin of 172 patients studied between Oct 1992 and Dec 1995 in Florence, Italy. Melatonin may mediate some of the Sun's effects upon the biosphere in certain frequency-windows such as a cis-half-year of about 5 months.

  20. Apparent absorption of solar spectral irradiance in heterogeneous ice clouds

    Microsoft Academic Search

    K. Sebastian Schmidt; Peter Pilewskie; Bernhard Mayer; Manfred Wendisch; Bruce Kindel; Steven Platnick; Michael D. King; Gala Wind; G. Tom Arnold; Lin Tian; Gerald Heymsfield; Heike Kalesse

    2010-01-01

    Coordinated flight legs of two aircraft above and below extended ice clouds played an important role in the Tropical Composition, Cloud and Climate Coupling Experiment (Costa Rica, 2007). The Solar Spectral Flux Radiometer measured up- and downward irradiance on the high-altitude (ER-2) and the low-altitude (DC-8) aircraft, which allowed deriving apparent absorption on a point-by-point basis along the flight track.

  1. Measurements and Modeling of Total Solar Irradiance in X-class Solar Flares

    NASA Technical Reports Server (NTRS)

    Moore, Christopher S.; Chamberlin, Phillip Clyde; Hock, Rachel

    2014-01-01

    The Total Irradiance Monitor (TIM) from NASA's SOlar Radiation and Climate Experiment can detect changes in the total solar irradiance (TSI) to a precision of 2 ppm, allowing observations of variations due to the largest X-class solar flares for the first time. Presented here is a robust algorithm for determining the radiative output in the TIM TSI measurements, in both the impulsive and gradual phases, for the four solar flares presented in Woods et al., as well as an additional flare measured on 2006 December 6. The radiative outputs for both phases of these five flares are then compared to the vacuum ultraviolet (VUV) irradiance output from the Flare Irradiance Spectral Model (FISM) in order to derive an empirical relationship between the FISM VUV model and the TIM TSI data output to estimate the TSI radiative output for eight other X-class flares. This model provides the basis for the bolometric energy estimates for the solar flares analyzed in the Emslie et al. study.

  2. Measurements and Modeling of Total Solar Irradiance in X-class Solar Flares

    NASA Astrophysics Data System (ADS)

    Moore, Christopher Samuel; Chamberlin, Phillip Clyde; Hock, Rachel

    2014-05-01

    The Total Irradiance Monitor (TIM) from NASA's SOlar Radiation and Climate Experiment can detect changes in the total solar irradiance (TSI) to a precision of 2 ppm, allowing observations of variations due to the largest X-class solar flares for the first time. Presented here is a robust algorithm for determining the radiative output in the TIM TSI measurements, in both the impulsive and gradual phases, for the four solar flares presented in Woods et al., as well as an additional flare measured on 2006 December 6. The radiative outputs for both phases of these five flares are then compared to the vacuum ultraviolet (VUV) irradiance output from the Flare Irradiance Spectral Model (FISM) in order to derive an empirical relationship between the FISM VUV model and the TIM TSI data output to estimate the TSI radiative output for eight other X-class flares. This model provides the basis for the bolometric energy estimates for the solar flares analyzed in the Emslie et al. study.

  3. Measurements and modeling of total solar irradiance in X-class solar flares

    SciTech Connect

    Moore, Christopher Samuel [Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 80309 (United States); Chamberlin, Phillip Clyde [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hock, Rachel [Space Vehicle Directorate, Air Force Research Laboratory, Kirtland Air Force Base, NM 87117 (United States)

    2014-05-20

    The Total Irradiance Monitor (TIM) from NASA's SOlar Radiation and Climate Experiment can detect changes in the total solar irradiance (TSI) to a precision of 2 ppm, allowing observations of variations due to the largest X-class solar flares for the first time. Presented here is a robust algorithm for determining the radiative output in the TIM TSI measurements, in both the impulsive and gradual phases, for the four solar flares presented in Woods et al., as well as an additional flare measured on 2006 December 6. The radiative outputs for both phases of these five flares are then compared to the vacuum ultraviolet (VUV) irradiance output from the Flare Irradiance Spectral Model (FISM) in order to derive an empirical relationship between the FISM VUV model and the TIM TSI data output to estimate the TSI radiative output for eight other X-class flares. This model provides the basis for the bolometric energy estimates for the solar flares analyzed in the Emslie et al. study.

  4. Influence of solar UVA on erythemal irradiances.

    PubMed

    Parisi, A V; Turnbull, D J; Kimlin, M G

    2006-06-21

    Many materials in everyday use such as window glass in homes and offices, glass in sunrooms and greenhouses, vehicle glass and some brands of sunscreens act as a barrier to the shorter UVB wavelengths while transmitting some of the longer UVA wavelengths. This paper reports on the erythemal exposures due to the UVA waveband encountered over a 12-month period for a solar zenith angle (SZA) range of 4 degrees to 80 degrees and the resulting times required for an erythemal exposure of one standard erythemal dose (SED) due to the erythemal exposures to the UVA wavelengths. The minimum time for an exposure of one SED due to the UVA wavelengths in winter is approximately double that what it is in summer. The time period of 40 to 60 min was the most frequent length of time for an exposure of one SED with 60 to 80 min the next frequent length of time required for a one SED exposure. PMID:16757874

  5. Proposed specification for the solar constant and air mass zero solar spectral irradiance

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The specification defines the solar constant and the zero air mass solar spectral irradiance for use in thermal analysis, thermal balance testing, and other tests of spacecraft and spacecraft components and materials. It is based upon data from experimental measurements made from high altitude aircraft, balloons, spacecraft, and the earth's surface. The stated accuracies are based on the estimated accuracies of the measurements, calibrations, and radiometric scales.

  6. The nature of the short period fluctuations in solar irradiance received by the earth

    Microsoft Academic Search

    Eric A. Smith; Thomas H. Vonder Haar; John R. Hickey; Bobert Maschhoff

    1983-01-01

    An analysis of the periodicities found in the Nimbus-7 satellite measurements of solar irradiance (Solar Constant) indicates variations on three scales. Two of these variations are shown to be related to variations in solar activity as given by various indicators of solar photosphere disturbances. The high frequency periodicity is due to the solar rotation period. The second periodicity is based

  7. Data-Driven Model for Solar Irradiation Based on Satellite Observations

    E-print Network

    Anitescu, Mihai

    most important factors of the solar irradiation vari- ability are the movement of the Sun and weather about the movement of the irradiation field, the dynamical system has a two-step delay. The dynamics that reaches the Earth from the Sun. In solar energy applications, part of the solar ir- radiation can

  8. Measuring solar spectral and angle-of-incidence effects on photovoltaic modules and solar irradiance sensors

    SciTech Connect

    King, D.L.; Kratochvil, J.A.; Boyson, W.E.

    1997-11-01

    Historically, two time-of-day dependent factors have complicated the characterization of photovoltaic module and array performance; namely, changes in the solar spectrum over the day and optical effects in the module that vary with the solar angle-of-incidence. This paper describes straightforward methods for directly measuring the effects of these two factors. Measured results for commercial modules, as well as for typical solar irradiance sensors (pyranometers) are provided. The empirical relationships obtained from the measurements can be used to improve the methods used for system design, verification of performance after installation, and diagnostic monitoring of performance during operation.

  9. Nimbus 7 Solar Backscatter Ultraviolet (SBUV) spectral scan solar irradiance and Earth radiance product user's guide

    NASA Technical Reports Server (NTRS)

    Schlesinger, Barry M.; Cebula, Richard P.; Heath, Donald F.; Fleig, Albert J.

    1988-01-01

    The archived tape products from the spectral scan mode measurements of solar irradiance (SUNC tapes) and Earth radiance (EARTH tapes) by the Solar Backscatter UV (SBUV) instrument aboard Nimbus 7 are described. Incoming radiation from 160 to 400 nm is measured at intervals of 0.2 nm. The scan-to-scan repeatability of the solar irradiance measurements ranges from approximately 0.5 to 1 percent longward of 280 nm, to 2 percent around 210 nm and 4 percent near 175 nm. The repeatability of the Earth radiance values ranges from 2 to 3 percent at longer wavelengths and low zenith angles to 10 percent at shorter wavelengths and high zenith angles. The tape formats are described in detail, including file structure and contents of each type of record. Catalogs of the tapes and the time period covered are provided, along with lists of the days lacking solar irradiance measurements and the days dedicated to Earth radiance measurements. The method for production of the tapes is outlined and quality control measures are described. How radiances and irradiances are derived from the raw counts, the corrections for changes in instrument sensitivity, and related uncertainties are discussed.

  10. Analysis of Cumulus Solar Irradiance Reflectance (CSIR) Events

    NASA Technical Reports Server (NTRS)

    Laird, John L.; Harshvardham

    1996-01-01

    Clouds are extremely important with regard to the transfer of solar radiation at the earth's surface. This study investigates Cumulus Solar Irradiance Reflection (CSIR) using ground-based pyranometers. CSIR events are short-term increases in solar radiation observed at the surface as a result of reflection off the sides of convective clouds. When sun-cloud observer geometry is favorable, these occurrences produce characteristic spikes in the pyranometer traces and solar irradiance values may exceed expected clear-sky values. Ultraviolet CSIR events were investigated during the summer of 1995 using Yankee Environmental Systems UVA-1 and UVB-1 pyranometers. Observed data were compared to clear-sky curves which were generated using a third degree polynomial best-fit line technique. Periods during which the observed data exceeded this clear-sky curve were identified as CSIR events. The magnitude of a CSIR event was determined by two different quantitative calculations. The MAC (magnitude above clear-sky) is an absolute measure of the difference between the observed and clear-sky irradiances. Maximum MAC values of 3.4 Wm(exp -2) and 0.069 Wm(exp -2) were observed at the UV-A and UV-B wavelengths, respectively. The second calculation determined the percentage above clear-sky (PAC) which indicated the relative magnitude of a CSIR event. Maximum UV-A and UV-B PAC magnitudes of 10.1% and 7.8%, respectively, were observed during the study. Also of interest was the duration of the CSIR events which is a function of sun-cloud-sensor geometry and the speed of cloud propagation over the measuring site. In both the UV-A and UV-B wavelengths, significant CSIR durations of up to 30 minutes were observed.

  11. The Search for Extraterrestrials

    NASA Astrophysics Data System (ADS)

    Ross, Monte

    It has been said that the discovery of an extraterrestrial intelligence will be the most important event in mankind’s history. For millennia, humans have been looking at the stars at night and wondering whether we are alone in the universe. Only with the advent of large-dish radio-frequency antennas and ultra-sensitive receivers in the late-twentieth century did it become possible to attempt a search for extraterrestrial intelligence (SETI).

  12. Browsing, Understanding, and Accessing Solar Irradiance Data via LISIRD

    NASA Astrophysics Data System (ADS)

    Wilson, A.; Lindholm, D. M.; Pankratz, C. K.

    2012-12-01

    The Laboratory for Atmospheric and Space Physics, LASP, has been conducting research in Atmospheric and Space science for over 60 years. In particular, LASP has made a variety of space-based measurements of solar irradiance, which provide crucial input for research and modeling in solar-terrestrial interactions, space physics, planetary, atmospheric, and climate sciences. These data sets are generally time series of measurements, solar indices, and spectra. Unlike many Earth science data sets, they are not geolocated and so cannot be referenced via latitude and longitude coordinates. Thus they are not appropriate for or interoperable with many existing geo scientific data access and analysis tools and need somewhat specialized tools to aid users in their understanding and use. The LASP Solar Irradiance Data Center, LISIRD, http://lasp.colorado.edu/lisird, is designed to allow the science community and the public to explore and access solar irradiance and related data sets. LISIRD's interactive plotting allows users to investigate and download spectral data sets from a variety of missions. We have recently expanded our offerings and now serve TIMED SEE Level 2, Level 3, and Level 4 data sets. We continue to serve SORCE Solar Spectral Irradiance, Total Solar Irradiance, and Magnesium II and well as the Flare Irradiance Spectral Model (FISM) and other data sets. LISIRD leverages middleware, the LASP Time series Server (LaTiS), that provides access to time series data based on time, wavelength, and parameter. LaTiS can read a wide variety of input formats from both local and remote sources, so many data sets can be served in their native format. It also supports dynamic data reformatting, so users can request the data and times in formats of their choice. LaTiS supports data subsetting so that users may download only regions of interest, and can stream the data directly into a computer program via a RESTful API in an automated fashion. We continue to improve LISIRD not just by integrating new data sets, but also by improving its data management and presentation. This means assigning unique identifiers to data sets and the granules that constitute them, which will support better identification and citation of our data sets. We will explore identification issues and solutions related to the dynamic generation of new data sets enabled by LaTiS. We are also improving the access to our metadata, including semantically enabling the site so that our data can be discovered, related concepts can be explored, our inventory can be browsed and searched, and our data understood well enough to be understood and used appropriately. This poster will describe the current state of LISIRD, provide details of the data sets it serves, demonstrate the role of the LaTiS middleware, discuss the assignment of unique identifiers to our data products, describe plans for integration of a semantically metadata database, and address other related aspects of serving spectral and other time series data.

  13. Modelling solar irradiance from HRV images of Meteosat Second Generation

    NASA Astrophysics Data System (ADS)

    Cony, Marco; Zarzalejo, Luis; Polo, Jesús; Marchante, Ruth; Martín, Luis

    2010-05-01

    Knowledge of solar radiation at the earth's surface is a need in designing any solar energy application. In particular both photovoltaic and solar thermal systems required high accurate data of solar radiation components. Nowadays the use of satellite images as input to models for deriving solar irradiance time series is accepted as a reliable methodology with good accuracy. In this sense, there are several models aimed at this objective. Among them it can be pointed out the Heliosat-2 method, based upon the first generation of Meteosat satellites, which has been broadly used. Taken this approach as reference a modified model was proposed including additional independent variables to the cloud index, such as the moments of the cloud index distribution and the air mass. This model was successfully assessed with about 30 ground data sites in Spain showing a good response. However, since 2006 the Meteosat Second Generation (MSG) is observing the earth-atmosphere system centred in zero longitude. This new satellite generation has improved technical characteristics compared to the former one, particularly those focused on radiometric, spectral, spatial and time resolutions. This work is aimed at describing the work to accommodate the former model based on Heliosat-2 to operate with the MSG images and characteristics. A comparison with the old model will be made in the overlapping period, 2006, and an assessment with available ground data will also be performed as well.

  14. Preliminary low temperature electron irradiation of triple junction solar cells

    NASA Technical Reports Server (NTRS)

    Stella, Paul M.; Mueller, Robert L.; Scrivner, Roy L.; Helizon, Roger S.

    2005-01-01

    JPL has routinely performed radiation testing on commercial solar cells and has also performed LILT testing to characterize cell performance under far sun operating conditions. This research activity was intended to combine the features of both capabilities to investigate the possibility of any room temperature annealing that might influence the measured radiation damage. Although it was not possible to maintain the test cells at a constant low temperature between irradiation and electrical measurements, it was possible to obtain measurements with the cell temperature kept well below room temperature.

  15. Ground-based measurements of solar irradiance variations.

    NASA Astrophysics Data System (ADS)

    Chapman, G. A.

    A brief review is presented of observing and data analysis programs being carried out at the San Fernando Observatory. A digital analysis of sunspot area from full disk photographs shows good correlation with areas published in the Solar Geophysical Data Bulletin with scale factor near unity. Results are presented from photoelectric photometry of active regions using the Extreme Limb Photometer. Results are presented for the August 1982 passage of a large active region. This active region caused a maximum dip in the quiet sun irradiance of about 800 parts per million.

  16. Temporal Variations of Solar UV Spectral Irradiance Caused by Solar Rotation and Active Region Evolution

    NASA Technical Reports Server (NTRS)

    Donnelly, R. F.; Heath, D. F.; Lean, J. L.; Rottman, G. J.

    1984-01-01

    Variations in the solar 100 to 400 nm UV spectral irradiance caused by solar rotation and active region evolution, are discussed as a function of UV wavelength, CMD dependence, and in relation to the temporal variations in the total solar irradiance, 10.7 cm radio flux, sunspot number and Ca K plage data. Active region radiation at cm wavelengths includes a component proportional to the magnetic field. Active region evolution involves a more rapid growth, peak and decay of sunspots and their strong magnetic fields than the Ca K plages and their related UV enhancements. Major plages often last a rotation or more longer than the active region's sunspots. Large active regions, including those associated with major dips in the total solar irradiance, tend to produce the strongest peaks in 10.7 cm and sunspot numbers on their first rotation, while the Ca K plages and UV enhancements peak on the next rotation and decay more slowly on subsequent rotations. Differences in CMD dependencies cause temporal differences including the stronger presence of 13 day variations in the UV flux.

  17. Skin Cancer, Irradiation, and Sunspots: The Solar Cycle Effect

    PubMed Central

    Zurbenko, Igor

    2014-01-01

    Skin cancer is diagnosed in more than 2 million individuals annually in the United States. It is strongly associated with ultraviolet exposure, with melanoma risk doubling after five or more sunburns. Solar activity, characterized by features such as irradiance and sunspots, undergoes an 11-year solar cycle. This fingerprint frequency accounts for relatively small variation on Earth when compared to other uncorrelated time scales such as daily and seasonal cycles. Kolmogorov-Zurbenko filters, applied to the solar cycle and skin cancer data, separate the components of different time scales to detect weaker long term signals and investigate the relationships between long term trends. Analyses of crosscorrelations reveal epidemiologically consistent latencies between variables which can then be used for regression analysis to calculate a coefficient of influence. This method reveals that strong numerical associations, with correlations >0.5, exist between these small but distinct long term trends in the solar cycle and skin cancer. This improves modeling skin cancer trends on long time scales despite the stronger variation in other time scales and the destructive presence of noise. PMID:25126567

  18. Impact of simulated solar irradiation on disinfection byproduct precursors.

    PubMed

    Chow, Alex T; Leech, Dina M; Boyer, Treavor H; Singer, Philip C

    2008-08-01

    The Sacramento-San Joaquin Delta is the major drinking water source for 23 million California residents. Consequently, many studies have examined disinfection byproduct (DBP) formation in relation to Delta dissolved organic carbon (DOC) concentration. However, DOC characteristics within the Delta are not the same as those entering downstream water treatment facilities. As water is transferred to Southern California through the California Aqueduct, a 714.5 km-open channel, it is exposed to sunlight, potentially altering DBP precursors. We collected water from three sites within the Delta and one nearthe California Aqueduct, representing different DOC sources, and irradiated them in a solar simulator at a dose equivalent to that received during four days conveyance in the aqueduct. Photolytic changes in DOC were assessed by measuring CO2 and organic acid production, fluorescence, and ultraviolet absorbance over time. Trihalomethane (THM) and haloacetic acid (HAA) formation potentials, as well as the distribution of hydrophobic, transphilic, and hydrophilic acid fractions were determined at exposures equivalent to one and four days. Solar irradiation significantly decreased ultraviolet absorbance and fluorescence intensity, produced organic acids, and increased the hydrophilic fraction of waters. These changes in DOC caused a shift in bromine incorporation among the THM and HAA species. Our results are the first to demonstrate the importance of sunlight in altering DOC with respect to DBP formation. PMID:18754480

  19. Correlation of electron and proton irradiation-induced damage in InP solar cells

    Microsoft Academic Search

    Robert J. Walters; Geoffrey P. Summers; Scott R. Messenger; Edward A. Burke

    1995-01-01

    When determining the best solar cell technology for a particular space flight mission, accurate prediction of solar cell performance in a space radiation environment is essential. The current methodology used to make such predictions requires extensive experimental data measured under both electron and proton irradiation. Due to the rising cost of accelerators and irradiation facilities, such extensive data sets are

  20. A proposed update to the solar irradiance spectrum used in LOWTRAN and MODTRAN

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Gao, Bo-Cai

    1993-01-01

    The calibrated upwelling radiance spectra measured by AVIRIS are increasingly being analyzed with radiative transfer codes. Analysis of AVIRIS data with the LOWTRAN and MODTRAN radiative transfer codes has led to indications of an error in the solar irradiance spectra used by these codes. This paper presents evidence for the error and proposed update to the solar irradiance spectra used by LOWTRAN and MODTRAN.

  1. A proposed update to the solar irradiance spectrum used in LOWTRAN and MODTRAN

    Microsoft Academic Search

    Robert O. Green; Bo-Cai Gao

    1993-01-01

    The calibrated upwelling radiance spectra measured by AVIRIS are increasingly being analyzed with radiative transfer codes. Analysis of AVIRIS data with the LOWTRAN and MODTRAN radiative transfer codes has led to indications of an error in the solar irradiance spectra used by these codes. This paper presents evidence for the error and proposed update to the solar irradiance spectra used

  2. Calculated solar cell Isc sensitivity to atmospheric conditions under direct and global irradiance

    NASA Astrophysics Data System (ADS)

    Osterwald, C. R.

    Using a new solar spectral irradiation computer model, a procedure has been devised which allows the calculation of short-circuit current (Isc) sensitivity to atmospheric variables. This procedure, which has applications for photovoltaic reference cell calibrations, clearly shows the Isc sensitivity to spectral distribution changes without the influence of the total irradiance level. Example outputs are presented for four different solar cell types.

  3. Searching for extraterrestrial civilizations

    NASA Technical Reports Server (NTRS)

    Kuiper, T. B. H.; Morris, M.

    1977-01-01

    Three interrelated assumptions are critically examined in an attempt to outline a productive strategy for a search for extraterrestrial intelligence. Questions concerning the feasibility of interstellar travel are investigated. It is concluded that the probability of interstellar travel is high enough that, given a modest number of advanced civilizations, at least one of them will engage in interstellar voyages and colonize the galaxy. Assuming, however, that technological civilizations are rare the galaxy would be essentially unpopulated. Attention is given to the present lack of contact with extraterrestrial beings and frequencies for interstellar beacons.

  4. SOHO/CELIAS Solar EUV Monitor (SEM) Absolute Solar EUV Irradiance Measurements Spanning Two Solar Minima (Invited)

    NASA Astrophysics Data System (ADS)

    Wieman, S. R.; Didkovsky, L. V.; Judge, D.

    2010-12-01

    The SOHO/CELIAS Solar EUV Monitor (SEM) has measured absolute EUV solar irradiance nearly continuously over a 15 year period that includes both the cycle 22/23 (1996) and cycle 23/24 (2008) solar minima. These measurements indicate that irradiance in the 26-34 nm spectral range, including the dominant He II 30.4 nm spectral line, was about 15% ± 6% lower during the more recent minimum compared to the previous minimum. The SEM data have been verified against measurements from seven sounding rocket calibration underflights that included a NIST calibrated SEM clone instrument as well as a Rare Gas Ionization Cell (RGIC) absolute extreme ultraviolet (EUV) detector. Additionally, the SEM measurements are in good agreement with measurements from the EUV Spectrophotomer (ESP) part of the EUV Variability Experiment (EVE) on SDO. ESP measurements from the EVE sounding rocket flight (2008) confirmed the very low solar EUV irradiance observed during the 23/24 minimum. A comparison of SEM and ESP data in the 30.4 nm spectral windows is presented.

  5. [Observation and analysis of solar ultraviolet irradiance spectrum in Chengdu area].

    PubMed

    Sun, Peng; He, Jie; Zhao, Xiao-Yan; Zuo, Hao-Yi; Yang, Jing-Guo

    2008-04-01

    The solar ultraviolet irradiance spectrum in Chengdu area from March to July in 2006 was observed with an ultraviolet CCD optical multi-channel analyzer. According to the observation results, some analysis of the basic characteristics was made. The analysis of the solar ultraviolet irradiance spectrum showed that the solar ultraviolet irradiance is weak in the morning and in the evening but strong at noon, reaches the strongest point in June, and reversely correlates with the change in SZA (solar zenith angle); the ratio of irradiance flux of UVB to UVA is less than 0.04, and usually, the ratio in the afternoon is bigger than that in the morning in sunny days; Fogs can cause the ratio to increase, the reason is that fogs show stronger influence on attenuation of UVA than UVB; Clouds absorbed the solar ultraviolet irradiance greatly. PMID:18619319

  6. Climate Sensitivity of Earth to Solar Irradiance: update II

    NASA Astrophysics Data System (ADS)

    Douglass, D. H.

    2005-05-01

    This paper is a continuation of a study by Douglass, Clader and Knox (DCKI) [1]. In that paper we determined the solar effect on the lower tropospheric global temperature T using the Total Solar Irradiance (TSI) of Frohlich and Lean (FL)[2]. The sensitivity k, determined primarily by the 11 year activity cycle, was found to be twice that expected from a no-feedback Stefan-Boltzmann radiation balance model implying positive feedback. A linear trend of 77mK/decade was also found from that analysis. Since DCKI it has come to our attention that there is another construction of TSI by Willson and Mordvinov (WM)[3]. The WM TSI shows the familiar 11 year cycle but differs from FL in that they find a positive trend for TSI while FL find a negative trend. We now do a new analysis on T using the TSI of WM to determine the differences. We expect the sensitivity k to be nearly the same. However, the linear trend estimate could be significantly reduced. 1. D. H. Douglass, B. D. Clader, and R. S. Knox, Paper presented at 2004 Solar Radiation and Climate (SORCE) meeting on Decade Variability in the Sun and the Climate. See http://arXiv.org/abs/physics/0411002. 2.C. Fröhlich and J. Lean, Geophys. Res. Lett. 25, 4377-4380 (1998). Version 18: http://www.obsun.pmodwrc.ch 3.R. C. Willson and A. V. Mordvinov. Geophys. Res. Lett. 30(5), article 1199 (2003)

  7. Extraterrestrial intelligence? The search is on

    NASA Technical Reports Server (NTRS)

    Coulter, Gary R.

    1991-01-01

    NASA's SETI-Microwave Observing Project, beginning on October 12, 1992, will search the closest solar-type stars for radio signals from extraterrestrial civilizations. When completed in the year 2000, the NASA search will have surpassed the search volume of all prior searches by a factor of 10 exp 10. The world's largest radio telescopes will be employed, in conjunction with the NASA Deep Space Network communications antennas. The program will be led by NASA-Ames, with substantial contribution by JPL.

  8. 60Co ?-ray and electron irradiation damage of GaAs single crystals and solar cells

    Microsoft Academic Search

    Masafumi Yamaguchi; Chikara Amano

    1983-01-01

    60Co ?-ray and high energy electrons (0.8–4 MeV) irradiation damage of GaAs solar cells were examined. Changes in minority carrier diffusion length in irradiated GaAs single crystals were also investigated by electron beam and 60Co ?-ray-induced current methods for solar cells. Damage constant of p-GaAs is smaller than that of n-GaAs. Equivalent damage rate in GaAs due to electron irradiation

  9. Low-energy proton irradiation effects on GaAs\\/Ge solar cells

    Microsoft Academic Search

    Rong Wang; Zengliang Guo; Guangpu Wang

    2006-01-01

    This paper reports the low-energy proton irradiation effects on GaAs\\/Ge solar cells for space use. The proton irradiation experiments were performed with a fluence of 1.2×1013cm?2, energies ranging from 0.1 to 3.0MeV. The results obtained demonstrate that the irradiation with a proton energy of 0.3MeV gives rise to the most degradation rates of Isc, Voc and Pmax of the solar

  10. The nature of the short period fluctuations in solar irradiance received by the earth

    Microsoft Academic Search

    Eric A. Smith; Thomas H. Vonder Haar; John R. Hickey; Bobert Maschhoff

    1983-01-01

    An analysis of the periodicities found in the Nimbus-7 satellite measurements of solar irradiance (Solar Constant) indicates\\u000a variations on three scales. Two of these variations are shown to be related to variations in solar activity as given by various\\u000a indicators of solar photosphere disturbances. The high frequency periodicity is due to the solar rotation period. The second\\u000a periodicity is based

  11. Searching for extraterrestrial civilizations

    Microsoft Academic Search

    T. B. H. Kuiper; M. Morris

    1977-01-01

    Three interrelated assumptions are critically examined in an attempt to outline a productive strategy for a search for extraterrestrial intelligence. Questions concerning the feasibility of interstellar travel are investigated. It is concluded that the probability of interstellar travel is high enough that, given a modest number of advanced civilizations, at least one of them will engage in interstellar voyages and

  12. Search for extraterrestrial intelligence

    Microsoft Academic Search

    P. Morrison; J. Billingham; J. Wolfe

    1979-01-01

    The findings of a series of workshops on the search for extraterrestrial intelligence are presented. The major conclusions of the deliberations are presented. Six of the most interesting and significant elements of the debate are presented in the form of Colloquies. A selection of detailed technical arguments about various aspects of the SETI endeavor is documented. (GHT)

  13. ExtraTerrestrial Intelligence

    E-print Network

    Walter, Frederick M.

    SETI Search for ExtraTerrestrial Intelligence I know perfectly well that at this moment the whole, The Madwoman of Chaillot #12;Options Passive SETI: Listen Active SETI: Transmit #12;Search Strategies Suppose you find a civilization. You want to communicate. How? #12;Search Strategies There are two issues: A

  14. Classification of extraterrestrial civilizations

    Microsoft Academic Search

    Tong B. Tang; Grace Chang

    1991-01-01

    A scheme of classification of extraterrestrial intelligence (ETI) communities based on the scope of energy accessible to the civilization in question is proposed as an alternative to the Kardeshev (1964) scheme that includes three types of civilization, as determined by their levels of energy expenditure. The proposed scheme includes six classes: (1) a civilization that runs essentially on energy exerted

  15. Correlation of solar irradiance and atmospheric temperature variations derived from spacecraft radiometry

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Bolden, William C.; Gibson, M. A.; Paden, Jack; Pandey, Dhirendra K.; Thomas, Susan; Wilson, Robert S.

    1992-01-01

    Long-term changes in the mean global atmospheric temperature and the total solar irradiance were examined utilizing 1979-1989 spacecraft measurements. Outgoing longwave radiation at the top of the atmosphere was employed to infer global atmospheric temperatures. Evidence was determined that indicates the global temperatures should decline in the 1990-1997 period as the magnitude of the incoming solar irradiance declines with decreasing solar magnetic activity.

  16. Prediction of global solar irradiance based on time series analysis: Application to solar thermal power plants energy production planning

    SciTech Connect

    Martin, Luis; Marchante, Ruth; Cony, Marco [Investigaciones y Recursos Solares Avanzados (IrSOLaV), Tres Cantos 2 8045 (Spain); Zarzalejo, Luis F.; Polo, Jesus; Navarro, Ana [Energy Department, CIEMAT, Madrid 28040 (Spain)

    2010-10-15

    Due to strong increase of solar power generation, the predictions of incoming solar energy are acquiring more importance. Photovoltaic and solar thermal are the main sources of electricity generation from solar energy. In the case of solar thermal energy plants with storage energy system, its management and operation need reliable predictions of solar irradiance with the same temporal resolution as the temporal capacity of the back-up system. These plants can work like a conventional power plant and compete in the energy stock market avoiding intermittence in electricity production. This work presents a comparisons of statistical models based on time series applied to predict half daily values of global solar irradiance with a temporal horizon of 3 days. Half daily values consist of accumulated hourly global solar irradiance from solar raise to solar noon and from noon until dawn for each day. The dataset of ground solar radiation used belongs to stations of Spanish National Weather Service (AEMet). The models tested are autoregressive, neural networks and fuzzy logic models. Due to the fact that half daily solar irradiance time series is non-stationary, it has been necessary to transform it to two new stationary variables (clearness index and lost component) which are used as input of the predictive models. Improvement in terms of RMSD of the models essayed is compared against the model based on persistence. The validation process shows that all models essayed improve persistence. The best approach to forecast half daily values of solar irradiance is neural network models with lost component as input, except Lerida station where models based on clearness index have less uncertainty because this magnitude has a linear behaviour and it is easier to simulate by models. (author)

  17. Ground-based measurements of solar irradiance variations

    NASA Astrophysics Data System (ADS)

    Chapman, G. A.

    1984-05-01

    Observations and analysis programs being carried out at the San Fernando Observatory are reviewed. A digital analysis of sunspot areas from full disk photographs shows an especially good correlation with areas published in the Solar Geophysical Data Bulletin with scale factor near unity. Results are presented from photoelectric photometry of active regions using the Extreme Limb Photometer. These results suggest energy balance between sunspots and faculae. Preliminary results are presented from a new program of photoelectric photometry using a linear array of diodes. Results are presented for the August 1982 passage of a large active region. This active region caused a maximum dip in the quiet Sun irradiance of about 800 parts per million.

  18. NEW SOLAR EXTREME-ULTRAVIOLET IRRADIANCE OBSERVATIONS DURING FLARES

    SciTech Connect

    Woods, Thomas N.; Hock, Rachel; Eparvier, Frank; Jones, Andrew R. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Chamberlin, Phillip C.; Klimchuk, James A. [NASA Goddard Space Flight Center, Solar Physics Laboratory, Greenbelt, MD 20771 (United States); Didkovsky, Leonid; Judge, Darrell [Space Sciences Center, University of Southern California, Los Angeles, CA 90089 (United States); Mariska, John; Warren, Harry [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Schrijver, Carolus J. [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304 (United States); Webb, David F. [Institute for Scientific Research, Boston College, Chestnut Hill, MA 02467 (United States); Bailey, Scott [Electrical and Computer Engineering Department, Virginia Tech, Blacksburg, VA 24061 (United States); Tobiska, W. Kent, E-mail: tom.woods@lasp.colorado.edu [Space Environment Technologies, Pacific Palisades, CA 90272 (United States)

    2011-10-01

    New solar extreme-ultraviolet (EUV) irradiance observations from the NASA Solar Dynamics Observatory (SDO) EUV Variability Experiment provide full coverage in the EUV range from 0.1 to 106 nm and continuously at a cadence of 10 s for spectra at 0.1 nm resolution and even faster, 0.25 s, for six EUV bands. These observations can be decomposed into four distinct characteristics during flares. First, the emissions that dominate during the flare's impulsive phase are the transition region emissions, such as the He II 30.4 nm. Second, the hot coronal emissions above 5 MK dominate during the gradual phase and are highly correlated with the GOES X-ray. A third flare characteristic in the EUV is coronal dimming, seen best in the cool corona, such as the Fe IX 17.1 nm. As the post-flare loops reconnect and cool, many of the EUV coronal emissions peak a few minutes after the GOES X-ray peak. One interesting variation of the post-eruptive loop reconnection is that warm coronal emissions (e.g., Fe XVI 33.5 nm) sometimes exhibit a second large peak separated from the primary flare event by many minutes to hours, with EUV emission originating not from the original flare site and its immediate vicinity, but rather from a volume of higher loops. We refer to this second peak as the EUV late phase. The characterization of many flares during the SDO mission is provided, including quantification of the spectral irradiance from the EUV late phase that cannot be inferred from GOES X-ray diagnostics.

  19. Solar total irradiance variations and the global sea surface temperature record

    Microsoft Academic Search

    George C. Reid

    1991-01-01

    The record of globally averaged sea surface temperature (SST) over the past 130 years shows a highly significant correlation with the envelope of the 11-year cycle of solar activity over the same period. This correlation could be explained by a variation in the sun's total irradiance (the solar constant) that is in phase with the solar-cycle envelope, supporting and updating

  20. An algorithm to evaluate solar irradiance and effective dose rates using spectral UV irradiance at four selected wavelengths.

    PubMed

    Anav, A; Rafanelli, C; Di Menno, I; Di Menno, M

    2004-01-01

    The paper shows a semi-analytical method for environmental and dosimetric applications to evaluate, in clear sky conditions, the solar irradiance and the effective dose rates for some action spectra using only four spectral irradiance values at selected wavelengths in the UV-B and UV-A regions (305, 320, 340 and 380 nm). The method, named WL4UV, is based on the reconstruction of an approximated spectral irradiance that can be integrated, to obtain the solar irradiance, or convoluted with an action spectrum to obtain an effective dose rate. The parameters required in the algorithm are deduced from archived solar spectral irradiance data. This database contains measurements carried out by some Brewer spectrophotometers located in various geographical positions, at similar altitudes, with very different environmental characteristics: Rome (Italy), Ny Alesund (Svalbard Islands, Norway) and Ushuaia (Tierra del Fuego, Argentina). To evaluate the precision of the method, a double test was performed with data not used in developing the model. Archived Brewer measurement data, in clear sky conditions, from Rome and from the National Science Foundation UV data set in San Diego (CA, USA) and Ushuaia, where SUV 100 spectroradiometers operate, were drawn randomly. The comparison of measured and computed irradiance has a relative deviation of about +/-2%. The effective dose rates for action spectra of Erythema, DNA and non-Melanoma skin cancer have a relative deviation of less than approximately 20% for solar zenith angles <50 degrees . PMID:15266087

  1. The measurement of solar spectral irradiances at wavelengths between 40 and 4000 A

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1983-01-01

    Two 1/8-meter Ebert-Fastie spectrometers were refurbished and upgraded in order to measure the solar spectral irradiances between 1160 A and 3100 A. An evacuated 1/4-meter normal-incidence spectrometer was also fabricated for spectral irradiance measurements over the wavelength range from 1250 A to 250 A. Procedures were developed for the calibration of all three instruments utilizing standards at the National Bureau of Standards. The two 1/8-meter spectrometers were flown to measure the solar spectral irradiances near solar maximum on two different dates. Data from these flights were analyzed. The performance of the spectrometers, and the results of an analysis of the variabilities of the solar spectral irradiances over the solar cycles 20 and 21 are discussed.

  2. Biological dosimetry of solar radiation for different simulated ozone column thicknesses.

    PubMed

    Horneck, G; Rettberg, P; Rabbow, E; Strauch, W; Seckmeyer, G; Facius, R; Reitz, G; Strauch, K; Schott, J U

    1996-02-01

    During the Spacelab mission D-2, in the experiment RD-UVRAD, precalibrated biofilms consisting of dry monolayers of immobilised spores of Bacillus subtilis (strain Marburg) were exposed, for defined intervals, to extraterrestrial solar radiation filtered through an optical filtering system, to simulate different ozone column thicknesses. After the mission, the biofilms were processed and optical densities indicative of any biological activity were determined for each exposure condition by image analysis. For the different simulated ozone column thicknesses, biologically effective irradiances were experimentally determined from the biofilm data and compared with calculated data using a radiative transfer model and the known biofilm action spectrum. The data show a strong increase in biologically effective solar UV irradiance with decreasing (simulated) ozone concentrations. The full spectrum of extraterrestrial solar radiation leads to an increment of the biologically effective irradiance by nearly three orders of magnitude compared with the solar spectrum at the surface of the Earth for average total ozone columns. PMID:8622182

  3. Validation of the UARS solar ultraviolet irradiances: Comparison with the ATLAS 1 and 2 measurements

    NASA Astrophysics Data System (ADS)

    Woods, T. N.; Prinz, D. K.; Rottman, G. J.; London, J.; Crane, P. C.; Cebula, R. P.; Hilsenrath, E.; Brueckner, G. E.; Andrews, M. D.; White, O. R.; VanHoosier, M. E.; Floyd, L. E.; Herring, L. C.; Knapp, B. G.; Pankratz, C. K.; Reiser, P. A.

    1996-04-01

    The measurements of the solar ultraviolet spectral irradiance made by the two Upper Atmosphere Research Satellite (UARS) solar instruments, Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) and SOLar STellar Irradiance Comparison Experiment (SOLSTICE), are compared with same-day measurements by two solar instruments on the shuttle ATmospheric Laboratory for Applications and Science (ATLAS) missions, ATLAS SUSIM and Shuttle Solar Backscatter Ultra Violet (SSBUV) experiment. These measurements from the four instruments agree to within the 2? uncertainty of any one instrument, which is 5 to 10% for all wavelengths above 160 nm and for strong emission features below 160 nm. Additionally, the long-term relative accuracy of the two UARS data sets is better than the original 2% goal, especially at wavelengths greater than 160 nm. This level of agreement is credited to accurate preflight calibrations coupled with comprehensive inflight calibrations to track instrument degradation. Two solar irradiance spectra, 119 to 410 nm, are presented; the first combines observations from UARS SUSIM and UARS SOLSTICE taken on March 29, 1992, during the ATLAS 1 mission, and the second combines spectra for April 15, 1993, during the ATLAS 2 mission. The ATLAS 1 mission coincided with the initial decline from the maximum of solar cycle 22 when solar activity was relatively high. The ATLAS 2 mission occurred somewhat later during the declining phase of the solar cycle 22 when solar activity was more moderate.

  4. Estimation of the ozone and temperature sensitivity to the variation of spectral solar flux

    Microsoft Academic Search

    E. Rozanov; T. Egorova; C. Fröhlich; M. Haberreiter; T. Peter; W. Schmutz

    2002-01-01

    We have applied a 1-D steady-state radiative-convective model with interactive photochemistry to estimate the sensitivity of temperature and ozone mixing ratio to the observed variability of the extraterrestrial spectral solar irradiance. We have carried out several runs using the spectral solar flux for minimum and maximum solar activity conditions. The results show that the ozone and temperature in the stratosphere

  5. Geiger M., Diabat L., Mnard L., Wald L., Controlling the quality of solar irradiation data by means of a web service. European Geophysical Society, 27th General Assembly, Geophysical Research Abstracts, vol. 4, April

    E-print Network

    Paris-Sud XI, Université de

    & Modélisation, Centre d'Energétique, Ecole des Mines de Paris, BP 207, 06904 Sophia Antipolis cedex, France. Tel observations with some expectations based upon the extraterrestrial irradiation and a simulation

  6. Space observations of the variability of solar irradiance in the near and far ultraviolet

    NASA Technical Reports Server (NTRS)

    Heath, D. F.

    1972-01-01

    Satellite observations of the ultraviolet solar irradiance in selected wavelength bands between 1200 and 3000 a were made continuously by photometers consisting of broad-band sensors operated on Numbus 3 and 4 which were launched in April 1969 and 1970. In addition, spectrophotometer measurements of the solar irradiance were made with a dispersive instrument at 12 selected wavelengths from 2550 to 3400 a with a 10 a bandpass on Nimbus 4. Variations of the solar irradiance associated with the solar rotational period were observed since the launch of Nimbus 3. These variations are apparently associated with two source regions separated by about 180 deg in solar longitude. The change in irradiance with solar rotation was found to increase with decreasing wavelengths. Different types of the observed variations in uv solar irradiance can be classified in accordance with characteristics times, e.g. in the order of increasing periods as follows: (1)flare associated enhancements (2) 27-day variations due to solar rotation; (3) a possible biennial effect; and (4) long term variations associated with the 11-year solar cycle.

  7. Extraterrestrial Handedness: A Reply

    NASA Astrophysics Data System (ADS)

    Bonner, William A.; Rubenstein, Edward; Brown, George S.

    1999-05-01

    Recent investigations of stable isotope ratios of amino acids from the Murchison meteorite have shown them to be of unambiguous extraterrestrial origin, and examinations of their enantiomeric compositions, where terrestrial contamination can be excluded, have found a consistent excess of L-enantiomers. One explanation for this observation has been the asymmetric photolysis of racemic extraterrestrial amino acids by circularly polarized light (CPL) in the synchrotron radiation from orbiting electrons around the pulsar remnants of supernovae. Mason (1997) has attempted to discredit this mechanism on the grounds that circular dichroism (CD) bands for optically active molecules alternate in sign and sum to zero over the entire spectrum, and hence enantioselective photochemical reactions cannot be induced by broad band CPL. We submit arguments disputing this conclusion and present reasons for expecting that broad band CPL synchrotron radiation would be quite capable of inducing asymmetric photolysis, particularly in aliphatic amino acids.

  8. [An encounter with extraterrestrial intelligence].

    PubMed

    Hisabayashi, Hisashi

    2003-12-01

    It is much easier to find extraterrestrial intelligence than to detect simple organisms living on other planets. However, it is hard to communicate with such intelligence without the mutual understanding of inter-stellar communication protocol. The radio SETI (The Search for Extra-Terrestrial Intelligence) was initiated with the pioneering work of F. Drake in 1960, one year after the historical SETI paper by Cocconi and Morrison. This talk explains that SETI evolves with two bases of science; the understanding of our universe and the development of technology. Since SETI has had strong connection with radio astronomy from its early beginning, the impacts of radio astronomical findings and technological breakthrough can be seen in many aspects of the SETI history. Topics of this talk include the detection of microwave 3 K background radiation in the universe. Interstellar atomic and molecular lines found in radio-wave spectra provide the evidence of pre-biotic chemical evolution in such region. Radio telescope imaging and spectral technique are closely associated with methodology of SETI. Topics of the talk extend to new Allen Telescope Array and projected Square Kilometer Array. Recent optical SETI and the discoveries of extra solar planets are also explained. In the end, the recent understanding of our universe is briefly introduced in terms of matter, dark matter and dark energy. Even our understanding of the universe has been evolutionarily revolved and accumulated after 1960, we must recognize that our universe is still poorly understood and that astronomy and SETI are required to proceed hand in hand. PMID:15136757

  9. Photo-recovery of electron-irradiated GaAs solar cells

    Microsoft Academic Search

    Andrew Meulenberg

    1995-01-01

    The first long-term (3000 hours) UV testing of unirradiated and 1 MeV electron-irradiated GaAs solar cells, with multilayer-coated coverslides to reduce solar array operating temperature, has produced some unexpected and important results. Two results, independent of the coverslide coatings, are of particular importance in terms of the predictability of GaAs solar-array lifetime in space: ( 1) The GaAs\\/Ge solar cells

  10. SAS Honors Seminar 256: Extraterrestrial Life

    E-print Network

    Baker, Andrew J.

    SAS Honors Seminar 256: Extraterrestrial Life 12/1/2011 #12; Readings for Tuesday Cushman responses to extraterrestrial life" #12; Audio recordings for Tuesday From the 2010 Royal Society conference "Towards a scientific and societal agenda on extraterrestrial life" (http

  11. Reconstruction of daily solar UV irradiation from 1893 to 2002 in Potsdam, Germany

    NASA Astrophysics Data System (ADS)

    Junk, Jürgen; Feister, Uwe; Helbig, Alfred

    2007-08-01

    Long-term records of solar UV radiation reaching the Earth’s surface are scarce. Radiative transfer calculations and statistical models are two options used to reconstruct decadal changes in solar UV radiation from long-term records of measured atmospheric parameters that contain information on the effect of clouds, atmospheric aerosols and ground albedo on UV radiation. Based on earlier studies, where the long-term variation of daily solar UV irradiation was derived from measured global and diffuse irradiation as well as atmospheric ozone by a non-linear regression method [Feister et al. (2002) Photochem Photobiol 76:281 293], we present another approach for the reconstruction of time series of solar UV radiation. An artificial neural network (ANN) was trained with measurements of solar UV irradiation taken at the Meteorological Observatory in Potsdam, Germany, as well as measured parameters with long-term records such as global and diffuse radiation, sunshine duration, horizontal visibility and column ozone. This study is focussed on the reconstruction of daily broad-band UV-B (280 315 nm), UV-A (315 400 nm) and erythemal UV irradiation (ER). Due to the rapid changes in cloudiness at mid-latitude sites, solar UV irradiance exhibits appreciable short-term variability. One of the main advantages of the statistical method is that it uses doses of highly variable input parameters calculated from individual spot measurements taken at short time intervals, which thus do represent the short-term variability of solar irradiance.

  12. Finding extraterrestrial sites for thermophiles.

    PubMed

    Naylor, T

    2004-04-01

    Virtually our entire knowledge of the universe comes from two sorts of measurement of the electromagnetic radiation from the stars and galaxies within it; either their flux through relatively wide bandpasses (photometry), or measurements of the shape and wavelength of relatively narrow lines via spectroscopy. These techniques are now being used to discover planets outside our solar system, and perhaps in the next 10 years will begin to characterize them. If a serious search is to be made for extraterrestrial thermophiles, we need predictions for the effects of thermophiles on their host planets that are observable with these techniques. In this paper I shall outline what sorts of observation are likely to be used in the next 15 years for extra-solar planet work. All of the journal articles quoted here can be found through http://adsabs.harvard.edu/abstract_service.html, and often also accessed as preprints at http://uk.arxiv.org/form/astro%20ph?MULTI=form%20+/-%20interface. PMID:15046563

  13. Results of aperture area comparisons for exo-atmospheric total solar irradiance measurements.

    PubMed

    Johnson, B Carol; Litorja, Maritoni; Fowler, Joel B; Shirley, Eric L; Barnes, Robert A; Butler, James J

    2013-11-20

    Exo-atmospheric solar irradiance measurements made by the solar irradiance community since 1978 have incorporated limiting apertures with diameters measured by a number of metrology laboratories using a variety of techniques. Knowledge of the aperture area is a critical component in the conversion of radiant flux measurements to solar irradiance. A National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) sponsored international comparison of aperture area measurements of limiting apertures provided by solar irradiance researchers was performed, the effort being executed by the National Institute of Standards and Technology (NIST) in coordination with the EOS Project Science Office. Apertures that had institutional heritage with historical solar irradiance measurements were measured using the absolute aperture measurement facility at NIST. The measurement technique employed noncontact video microscopy using high-accuracy translation stages. We have quantified the differences between the participating institutions' aperture area measurements and find no evidence to support the hypothesis that preflight aperture area measurements were the root cause of discrepancies in long-term total solar irradiance satellite measurements. Another result is the assessment of uncertainties assigned to methods used by participants. We find that uncertainties assigned to a participant's values may be underestimated. PMID:24513747

  14. Intercomparison of solar UV direct irradiance spectral measurements at Izana in June 2005

    Microsoft Academic Search

    A. Bais; M. Blumthaler; A. Webb; G. Seckmeyer; S. Thiel; S. Kazadzis; A. Redondas; R. Kift; N. Kouremeti; B. Schallhart; R. Schmitt; D. Pissulla; J. P. Diaz; O. Garcia; A. M. Diaz Rodriguez; A. Smedley

    2005-01-01

    Spectral measurements of direct solar ultraviolet irradiance are very important for many applications in the field of atmospheric sciences. Despite its usefulness, few UV monitoring sites include such measurements in their regular observational programs. Standardization of measurement methodologies and calibration techniques is required in order to reach the quality standard of global irradiance measurements. This study presents preliminary results from

  15. Effects of solar UV irradiation on the tensile properties and structure of PPTA fiber

    Microsoft Academic Search

    Huapeng Zhang; Jianchun Zhang; Jianyong Chen; Xinmin Hao; Shanyuan Wang; Xinxing Feng; Yuhai Guo

    2006-01-01

    This paper comprehensively studied the effects of simulated solar ultraviolet irradiation on the mechanical and structural properties of the Twaron2000 para-aramid fiber by use of mechanical test, SEM, XRD, DSC, DMA and ATR-IR measurements. The results showed that after UV irradiation, the mechanical properties of the fiber were decreased obviously, and UV irradiation deteriorated the surface and defect areas of

  16. Interpretation of solar irradiance monitor measurements through analysis of 3D MHD simulations

    SciTech Connect

    Criscuoli, S.; Uitenbroek, H. [National Solar Observatory, Sacramento Peak, P.O. Box 62, Sunpsot, NM 88349 (United States)

    2014-06-20

    Measurements from the Spectral Irradiance Monitor (SIM) on board the Solar Radiation and Climate Experiment mission indicate that solar spectral irradiance at visible and IR wavelengths varies in counter phase with the solar activity cycle. The sign of these variations is not reproduced by most of the irradiance reconstruction techniques based on variations of surface magnetism employed so far, and it is not yet clear whether SIM calibration procedures need to be improved or if instead new physical mechanisms must be invoked to explain such variations. We employ three-dimensional magnetohydrodynamic simulations of the solar photosphere to investigate the dependence of solar radiance in SIM visible and IR spectral ranges on variations of the filling factor of surface magnetic fields. We find that the contribution of magnetic features to solar radiance is strongly dependent on the location on the disk of the features, which are negative close to disk center and positive toward the limb. If features are homogeneously distributed over a region around the equator (activity belt), then their contribution to irradiance is positive with respect to the contribution of HD snapshots, but decreases with the increase of their magnetic flux for average magnetic flux larger than 50 G in at least two of the visible and IR spectral bands monitored by SIM. Under the assumption that the 50 G snapshots are representative of quiet-Sun regions, we thus find that the Spectral Irradiance can be in counter-phase with the solar magnetic activity cycle.

  17. The search for extraterrestrial intelligence

    Microsoft Academic Search

    T. L. Wilson

    2001-01-01

    As far as we know, humanity is alone in the Universe: there is no definite evidence for the existence of extraterrestrial life, let alone extraterrestrial civilizations (ETCs) capable of communicating or travelling over interstellar distances. Yet popular speculation about the existence of ETCs abounds, including reports of alien visitations either now or in the past. But there is a middle

  18. Volcanic ash - Terrestrial versus extraterrestrial

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.

    1976-01-01

    A principal difference between terrestrial and extraterrestrial lavas may consist in the greater ability of terrestrial lavas to form thin films (like those of soap bubbles) and hence foams. It would follow that, in place of the pumice and spiny shards found in terrestrial volcanic ash, an extraterrestrial ash should contain minute spherules. This hypothesis may help to explain lunar microspherules.

  19. Atmospheric Sensitivity to Spectral Top-of-Atmosphere Solar Irradiance Perturbations, Using MODTRAN-5 Radiative Transfer Algorithm

    Microsoft Academic Search

    G. Anderson; A. Berk; G. Harder; J. Fontenla; E. Shettle; P. Pilewski; B. Kindel; J. Chetwynd; J. Gardner; M. Hoke; A. Jordan; R. Lockwood; G. Felde; P. Archarya

    2006-01-01

    The opportunity to insert state-of-the-art solar irradiance measurements and calculations, with subtle perturbations, into a narrow spectral resolution radiative transfer model has recently been facilitated through release of MODTRAN-5 (MOD5). The new solar data are from: (1) SORCE satellite measurements of solar variability over solar rotation cycle, & (2) ultra-narrow calculation of a new solar source irradiance, extending over the

  20. Status of the ISO draft standard for determining solar irradiances (WD 21348)

    NASA Astrophysics Data System (ADS)

    Tobiska, W.; Nusinov, A.

    A draft international standard is being developed through ISO TC20/SC14/WG4 to specify all representations of solar irradiances. Because the discipline area of solar irradiance measurements and modeling is dramatically evolving through improved instrumentation, measurement techniques, and modeling capabilities, the draft standard is proposed as a process-based standard. This format is designed to encourage the ongoing developments in the field. The draft standard covers all representations of solar irradiances and is applicable to measurements, reference spectra, empirical models, and first-principles models. The purpose of the standard is to provide a common specification for all solar irradiances for use by space systems materials and environment users. A solar irradiance specification would be compliant with the standard if four criteria are followed. First, solar irradiances would be reported, at the minimum, in SI units of Watts per square meter corrected to 1 AU. Second, the method of determining irradiances would be documented for data collection, processing, archiving, validation, accuracy, precision, methodology, and algo-rithm information. Where applicable, a description of proxies and independent data sets used in the derivation of empirical models, including the rationale for proxy selection, and the mathematical formulation for numerical models would be provided. Third, a compliant data set or model would be published in an internationally- available peer review journal. Fourth, the compliant data set or model would be archived in a method consistent with current technology that ensures international accessibility. A draft of the solar irradiance standard is publicly available for comment at the web site http://SpaceWx.com/.

  1. Ground-level spectral distribution of solar direct-normal irradiance and marine aerosol attenuation coefficients at Reunion Island

    Microsoft Academic Search

    P. Vaxelaire; J. Leveau; S. Baldy; G. Menguy

    1991-01-01

    The ground-level spectral distribution of direct solar irradiance at Reunion Island was measured for six bands covering the spectrum of solar radiation. The measurements, distributed over one year, were made under clear sky conditions with a pyrheliometer (Eppley, NIP) and six large pass-band flat filters. Good stability of spectral irradiances as a function of solar height allows us to propose

  2. A new model of solar EUV irradiance variability 2. Comparisons with empirical models and observations and implications for space weather

    Microsoft Academic Search

    J. L. Lean; H. P. Warren; J. T. Mariska; J. Bishop

    2003-01-01

    Motivated by the need for reliable specification of the Sun's electromagnetic radiation in the extreme ultraviolet (EUV) spectrum, we have developed a new model of solar EUV irradiance variability at wavelengths from 50 to 1200 Å. Solar images are used to quantify changes in the sources of EUV irradiance during the solar cycle. Optically thin EUV emission line fluxes are

  3. A new model of total solar irradiance based on sunspot areas

    Microsoft Academic Search

    Dora G. Preminger; Stephen R. Walton

    2005-01-01

    We show that daily sunspot area can be used in a simple model to reconstruct daily variations in the total solar irradiance, S. The model assumes that all fluctuations in S are correlated with the emergence of sunspots on the solar disk. Cotemporal data for S and sunspot area are analysed to extract the finite impulse response function that describes

  4. Modeling Solar Spectral Irradiance and Total Magnetic Flux Using Sunspot Areas

    Microsoft Academic Search

    Dora G. Preminger; Stephen R. Walton

    2006-01-01

    We show that daily sunspot areas can be used in a simple, single parameter model to reconstruct daily variations in several other solar parameters, including solar spectral irradiance and total magnetic flux. The model assumes that changes in any given parameter can be treated mathematically as the response of the system to the emergence of a sunspot. Using cotemporal observational

  5. Investigation of the Relative Value of Solar Proxies for Irradiance Variation

    NASA Technical Reports Server (NTRS)

    Jordan, Stuart; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    Recent space observations of irradiance change during the current solar cycle 23 suggest that of the three proxies currently used (PSI index, total solar magnetic field, and the Mg II c/w index) only the latter yields a consistent result when compared to the two previous cycles for which space observations are available. Possible reasons for this are presented, and a case is made that using actual sunspot areas might work almost as well as the PSI index for estimating irradiance changes, making earlier observations lacking photometric calibration of value in assessing probable irradiance changes over earlier sunspot cycles.

  6. Modeling solar irradiance variations through full-disk images and semi-empirical atmospheric models

    NASA Astrophysics Data System (ADS)

    Ermolli, I.; Caccin, B.; Centrone, M.; Penza, V.

    We summarize the results of both accurate measurement and models calculations carried out with the aim of understanding the physical origins of the solar irradiance variability arising from variations of surface structures through the solar activity cycle. In particular, we used the new high-quality measurements of the photospheric contrast of facular regions and the network, together to the accurate description of the temporal variation of their disk coverage since the last solar minimum obtained analyzing the archive of daily observations carried out with the PSPT at the Rome Observatory. We used these image analysis results together to the output of semi-empirical models of solar features to compute variations of the solar irradiance during periods spanning from few weeks up to the full ascending phase of the current solar cycle. We present the comparison of the computed variations with those measured by Virgo radiometers on board of SOHO.

  7. Wavelength dependence of solar flare irradiance enhancement and its influence on the thermosphere-ionosphere system

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Richmond, A. D.; Deng, Y.; Qian, L.; Solomon, S. C.; Chamberlin, P. C.

    2012-12-01

    The wavelength dependence of irradiance enhancement during solar flare is one of the important factors in determining how the Thermosphere-Ionosphere (T-I) system responds to flares. To investigate the wavelength dependence of irradiance, the Flare Irradiance Spectral Model (FISM) was run for 34 X-class flares. The results show that the percentage increases of solar irradiance at flare peak have a clear wavelength dependence. In the wavelength range between 0 - 195 nm, it can vary from 1% to 10000%. The solar irradiance enhancement is largest (~1000%) in the XUV range (0 - 25 nm), and is about 100% in the EUV range (25 - 120 nm). The influence of different wavebands on the T-I system during the October 28th, 2003 flare (X17.2-class) has also been examined using the latest version of the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). While the enhancement of the globally integrated solar energy deposition is largest in the 0 - 14 nm waveband, the impact of solar irradiance enhancement on the thermosphere at 400km is largest for the 25 - 105 nm waveband. The effect of the enhancement of the 122 - 195 nm waveband is small in magnitude, but it decays slowly.

  8. Optical Search for Extraterrestrial Intelligence with Air Cerenkov Telescopes

    Microsoft Academic Search

    David Eichler; Gregory Beskin

    2001-01-01

    We propose using large Air Cerenkov telescopes (ACTs) to search for optical, pulsed signals from extraterrestrial intelligence. Such dishes collect tens of photons from a nanosecond-scale pulse of isotropic equivalent power of tens of solar luminosities at a distance of 100 pc. The field of view for giant ACTs can be on the order of 10 square degrees, and they

  9. The Case for the Extraterrestrial Origin of Flying Saucers

    Microsoft Academic Search

    Stanton T. Friedman; Pembroke Crescent

    Careful review of a vast array of relevant evidence clearly leads to the conclusion that some unidentified flying objects are intelligently controlled vehicles whose origin is outside our solar system. All the arguments against the extraterrestrial origin seem to be based upon false reasoning, misrepresentation of evidence, neglect of relevant information, ignorance of relevant technology, or pseudo sophisticated assumptions about

  10. Recovery of shallow junction GaAs solar cells damaged by electron irradiation

    Microsoft Academic Search

    G. H. Walker; E. J. Conway

    1978-01-01

    Solar cells operated in space are subject to degradation from electron and proton radiation damage. It has been found that for deep junction p-GaAlAs\\/p-GaAs solar cells some of the electron radiation damage is removed by annealing the cells at 200 C. The reported investigation shows that shallow junction p-GaAlAs\\/p-GaAs\\/n-GaAs heteroface solar cells irradiated with 1 MeV electrons show a more

  11. Comparison of model estimated and measured direct-normal solar irradiance

    Microsoft Academic Search

    Rangasayi N. Halthore; Stephen E. Schwartz; Joseph J. Michalsky; Gail P. Anderson; Richard A. Ferrare; Brent N. Holben; Harry M. Ten Brink

    1997-01-01

    Direct-normal solar irradiance (DNSI), the energy in the solar spectrum incident in unit time at the Earth{close_quote}s surface on a unit area perpendicular to the direction to the Sun, depends only on atmospheric extinction of solar energy without regard to the details of the extinction, whether absorption or scattering. Here we report a set of closure experiments performed in north

  12. A I-V analysis of irradiated Gallium Arsenide solar cells

    NASA Technical Reports Server (NTRS)

    Heulenberg, A.; Maurer, R. H.; Kinnison, J. D.

    1991-01-01

    A computer program was used to analyze the illuminated I-V characteristics of four sets of gallium arsenide (GaAs) solar cells irradiated with 1-MeV electrons and 10-MeV protons. It was concluded that junction regions (J sub r) dominate nearly all GaAs cells tested, except for irradiated Mitsubishi cells, which appear to have a different doping profile. Irradiation maintains or increases the dominance by J sub r. Proton irradiation increases J sub r more than does electron irradiation. The U.S. cells were optimized for beginning of life (BOL) and the Japanese for end of life (EOL). I-V analysis indicates ways of improving both the BOL and EOL performance of GaAs solar cells.

  13. Effects of the El Chichon Volcanic Cloud on Direct and Diffuse Solar Irradiances.

    NASA Astrophysics Data System (ADS)

    Baker, C. Bruce; Kuhn, William R.; Ryznar, Edward

    1984-03-01

    Direct normal and diffuse solar irradiances and 500 nm aerosol optical depths measured at the University of Michigan departed far from normal on 26 October 1982, when it is concluded that the main stratospheric cloud from the El Chichon volcanic eruption arrived at the 42°N latitude of the radiation measurement facility. For clear-sky data analyzed through 19 January 1983, direct solar is about 25% less than normal and diffuse solar is about 85% greater. For the same aerosol optical depths and solar zenith angles, the ratio of diffuse to direct is about 30% greater for about 0.3 cm of precipitable water but nearly the same for 0.9 cm. Aerosol optical depths are nearly three times greater for wind directions that naturally advect the cleanest air. The effect of circumsolar irradiance on the methods used to measure direct normal and diffuse irradiances cause the former to be overestimated and the latter to be underestimated.

  14. Extraterrestrial Organic Compounds in Meteorites

    NASA Technical Reports Server (NTRS)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  15. Raman imaging of extraterrestrial materials

    NASA Astrophysics Data System (ADS)

    Wang, Alian; Korotev, Randy L.; Jolliff, Bradley L.; Ling, Zongcheng

    2015-07-01

    Laser Raman Spectroscopy has been proposed and is under extensive development for surface exploration missions to planetary bodies of our Solar System. It reveals information on molecular structure and chemistry. The spatial distribution of molecular species in natural geological samples and planetary materials has significance for the geological processes by which they formed. Raman imaging is the best way to combine the molecular identification and characterization of geologic materials with their spatial distribution. This paper reports Raman imaging studies of five types of extraterrestrial materials and three terrestrial samples using a state-of-the-art Raman imaging system. The Raman spectral features of major, minor, and trace species in these samples, together with their spatial correlations revealed by these Raman imaging studies indicate the genetic relationships and the geological processes that these materials have been experienced. For robotic planetary surface exploration mission, a simple yet very useful molecular map of a sample can be generated by using line-scan or grid-scan of an in situ Raman system with tightly focused laser beam.

  16. A Comparison of the First Solar EUV Irradiance Measurements from the SDO/EVE EUV Spectrophotometer (ESP) with the SOHO/CELIAS Solar EUV Monitor (SEM) Absolute Solar EUV Irradiance

    NASA Astrophysics Data System (ADS)

    Didkovsky, Leonid; Judge, Darrell; Wieman, Seth; Woods, Thomas; Eparvier, Francis; Jones, Andrew

    First light measurements from the SDO/EVE EUV Spectrophotometer (ESP) are calibrated based on both ESP pre-flight radiometric calibration and the SDO EVE calibration rocket un-derflight (5 May 2010) measurements obtained with the ESP and Multiple EUV Grating Spec-trometers (MEGS), which are clones of the SDO EVE onboard instruments. SDO/EVE/ESP absolute solar EUV irradiances are compared with the SOHO/CELIAS Solar EUV Monitor (SEM) data to provide uninterrupted EUV measurements of solar irradiances since 1996. The continuing EUV measurements from SDO/EVE/ESP will advance our study of long-and short-term solar EUV variability, improve existing solar EUV irradiance models, and use as input for improving ionosphere and thermosphere model results.

  17. Quantifying solar spectral irradiance in aquatic habitats for the assessment of photoenhanced toxicity

    USGS Publications Warehouse

    Barron, M.G.; Little, E.E.; Calfee, R.; Diamond, S.

    2000-01-01

    The spectra and intensity of solar radiation (solar spectral irradiance [SSI]) was quantified in selected aquatic habitats in the vicinity of an oil field on the California coast. Solar spectral irradiance measurements consisted of spectral scans (280-700 rim) and radiometric measurements of ultraviolet (UV): UVB (280-320 nm) and UVA (320-400 nm). Solar spectral irradiance measurements were taken at the surface and at various depths in two marsh ponds, a shallow wetland, an estuary lagoon, and the intertidal area of a high-energy sandy beach. Daily fluctuation in SSI showed a general parabolic relationship with time; maximum structure-activity relationship (SAR) was observed at approximate solar noon. Solar spectral irradiance measurements taken at 10-cm depth at approximate solar noon in multiple aquatic habitats exhibited only a twofold variation in visible light and UVA and a 4.5-fold variation in UVB. Visible light ranged from 11,000 to 19,000 ??W/cm2, UVA ranged from 460 to 1,100 ??W/cm2, and UVB ranged from 8.4 to 38 ??W/cm2. In each habitat, the attenuation of light intensity with increasing water depth was differentially affected over specific wavelengths of SSI. The study results allowed the development of environmentally realistic light regimes necessary for photoenhanced toxicity studies.

  18. Variation in spectral irradiance of the SES solar simulator

    NASA Technical Reports Server (NTRS)

    Mcnutt, A. E.

    1971-01-01

    A test to determine the spectral characteristics of the solar simulation produced by the solar environment simulator (SES) comprised a statistical analysis to determine the spectral variance, and its effect on the average absorptivity of surface coatings.

  19. Segmentation of coronal features to understand the solar EUV and UV irradiance variability

    NASA Astrophysics Data System (ADS)

    Kumara, S. T.; Kariyappa, R.; Zender, J. J.; Giono, G.; Delouille, V.; Chitta, L. P.; Damé, L.; Hochedez, J.-F.; Verbeeck, C.; Mampaey, B.; Doddamani, V. H.

    2014-01-01

    Context. The study of solar irradiance variability is of great importance in heliophysics, the Earth's climate, and space weather applications. These studies require careful identifying, tracking and monitoring of active regions (ARs), coronal holes (CHs), and the quiet Sun (QS). Aims: We studied the variability of solar irradiance for a period of two years (January 2011-December 2012) using the Large Yield Radiometer (LYRA), the Sun Watcher using APS and image Processing (SWAP) on board PROBA2, and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). Methods: We used the spatial possibilistic clustering algorithm (SPoCA) to identify and segment coronal features from the EUV observations of AIA. The AIA segmentation maps were then applied on SWAP images, and parameters such as the intensity, fractional area, and contribution of ARs/CHs/QS features were computed and compared with the full-disk integrated intensity and LYRA irradiance measurements. Results: We report the results obtained from SDO/AIA and PROBA2/SWAP images taken from January 2011 to December 2012 and compare the resulting integrated full-disk intensity with PROBA2/LYRA irradiance. We determine the contributions of the segmented features to EUV and UV irradiance variations. The variations of the parameters resulting from the segmentation, namely the area, integrated intensity, and relative contribution to the solar irradiance, are compared with LYRA irradiance. We find that the active regions have a great impact on the irradiance fluctuations. In the EUV passbands considered in this study, the QS is the greatest contributor to the solar irradiance, with up to 63% of total intensity values. Active regions, on the other hand, contribute to about 10%, and off-limb structures to about 24%. We also find that the area of the features is highly variable suggesting that their area has to be taken into account in irradiance models, in addition to their intensity variations. Conclusions: We successfully show that the feature extraction allows us to use EUV telescopes to measure irradiance fluctuations and to quantify the contribution of each part to the EUV spectral solar irradiance observed with a calibrated radiometer. This study also shows that SPoCA is viable, and that the segmentation of images can be a useful tool. We also provide the measurement correlation between SWAP and AIA during this analysis.

  20. Free Flyer Total and Spectral Solar Irradiance Sensor (TSIS) and Climate Services Mission

    NASA Astrophysics Data System (ADS)

    Cahalan, R.; Pilewskie, P.; Woods, T.

    2012-04-01

    NOAA's planned Total and Spectral Solar Irradiance Sensor (TSIS) mission will fly along with the NOAA user service payloads Advanced Data Collection System (ADCS) and Search and Rescue Satellite Aided Tracking (SARSAT). In order to guarantee continuity in the 33-year solar irradiance climate data record, TSIS must be launched in time to overlap with current on-orbit solar irradiance instruments. Currently TSIS is moving towards a launch readiness date of January 2015. TSIS provides for continuation of the Total Irradiance Monitor (TIM) and the Spectral Irradiance Monitor (SIM) currently onboard NASA's Solar Radiation and Climate Experiment (SORCE) platform, launched in January 2003. The difficulty of ensuring continuity has increased due to the launch failure of NASA's Glory mission with its improved TIM. Achieving the needed overlap must now rely on extending SORCE, and maintaining the TSIS schedule. TSIS is one component of a NASA-NOAA joint program (JPSS) planned to transition certain climate observations to operational mode. We summarize issues of continuity, improvements being made to the TIM and SIM sensors, and plans to provide for traceability of total and spectral irradiance measurements to ground-based cryogenic standards.

  1. Free Flyer Total and Spectral Solar Irradiance Sensor (TSIS) and Climate Services Mission

    NASA Technical Reports Server (NTRS)

    Cahalan, R.; Pilewskie, P.; Woods, T.

    2012-01-01

    NOAA's planned Total and Spectral Solar Irradiance Sensor (TSIS) mission will fly along with the NOAA user service payloads Advanced Data Collection System (ADCS) and Search and Rescue Satellite Aided Tracking (SARSAT). In ' order to guarantee continuity in the 33-year solar irradiance climate data record, TSIS must be launched in time to overlap with current on-orbit solar irradiance instruments. Currently TSIS is moving towards a launch rcadinss date of January 2015. TSIS provides for continuation of the Total Irradiance Monitor (TIM) and the Spectral Irradiance Monitor (SIM) ,currently onboard NASA's Solar Radiation and Climate Experiment (SORCE) platform, launched in January 2003. The difficulty of ensuring continuity has increased due to the launch failure of NASA's Glory mission with its improved TIM. Achieving the needed overlap must now rely on extending SORCE. and maintaining the TSIS schedule. TSIS is one component of a NASA-NOAA joint program (JPSS) planned to transition certain climate observations to operational mode. We summarize issues of continuity, improvements being made to the TIM and 81M sensors, and plans to provide for traceability of total and spectral irradiance measurements to ground-based cryogenic standards.

  2. SDI: Solar Dome Instrument for Solar Irradiance Monitoring Tao Liu1, Ankur U. Kamthe1, Varick L. Erickson1, Carlos F. M. Coimbra2 and Alberto E. Cerpa1

    E-print Network

    Cerpa, Alberto E.

    SDI: Solar Dome Instrument for Solar Irradiance Monitoring Tao Liu1, Ankur U. Kamthe1, Varick L data for ground solar irradiance (direct normal and global irradiance) is a major obstacle for the de- velopment of adequate policies to promote and take advan- tage of existing solar technologies. Although

  3. Smartphone based Android app for determining UVA aerosol optical depth and direct solar irradiances.

    PubMed

    Igoex, Damien P; Parisi, Alfio; Carter, Brad

    2013-10-12

    This research describes the development and evaluation of the accuracy and precision of an Android app specifically designed, written and installed on a smartphone for detecting and quantifying incident solar UVA radiation and subsequently, aerosol optical depth at 340 nm and 380 nm. Earlier studies demonstrated that a smartphone image sensor can detect UVA radiation and the responsivity can be calibrated to measured direct solar irradiance. This current research provides the data collection, calibration, processing, calculations and display all on a smartphone. A very strong coefficient of determination of 0.98 was achieved when the digital response was recalibrated and compared to the Microtops sunphotometer direct UVA irradiance observations. The mean percentage discrepancy discrepancy for derived direct solar irradiance was only 4% and 6% for observations at 380 nm and 340 nm respectively, lessening with decreasing solar zenith angle. An 8% mean percent difference discrepancy was observed when comparing aerosol optical depth, also decreasing as solar zenith angle decreases. The results indicate that a specifically designed Android app linking and using a smartphone image sensor, calendar and clock, with additional external narrow bandpass and neutral density filters can be used as a field sensor to evaluate both direct solar UVA irradiance and low aerosol optical depths for areas with low aerosol loads. This article is protected by copyright. All rights reserved. PMID:24117514

  4. The UV-A and visible solar irradiance spectrum: inter-comparison of absolutely calibrated, spectrally medium resolution solar irradiance spectra from balloon- and satellite-borne measurements

    NASA Astrophysics Data System (ADS)

    Gurlit, W.; Bösch, H.; Bovensmann, H.; Burrows, J. P.; Butz, A.; Camy-Peyret, C.; Dorf, M.; Gerilowski, K.; Lindner, A.; Noël, S.; Platt, U.; Weidner, F.; Pfeilsticker, K.

    2004-12-01

    Within the framework of the ENVISAT/-SCIAMACHY satellite validation, solar irradiance spectra are absolutely measured at moderate resolution in the UV/visible spectral range (in the UV from 316.7-418 nm and the visible from 400-652 nm at a full width half maximum resolution of 0.55 nm and 1.48 nm, respectively) from aboard the azimuth-controlled LPMA/DOAS balloon gondola at around 32 km balloon float altitude. After accounting for the atmospheric extinction due to Rayleigh scattering and gaseous absorption (O3, and NO2), the measured solar spectra are compared with previous observations. Our solar irradiance is +1.6% larger than the re-calibrated Kurucz et al. (1984) solar spectrum (Fontenla et al., 1999, called MODTRAN 3.5) in the visible spectral range (435-650 nm), +1.5% larger in the (370-415 nm) wavelength interval, but -4% smaller in the UV spectral range (316.7-370 nm), when the Kurucz spectrum is convolved to the spectral resolution of our instrument. The same comparison with the SOLSPEC solar spectrum (Thuillier et al., 1997, 1998a, b) confirms the somewhat larger solar irradiance (+1.7%) measured by the balloon instrument from 435-500 nm, but not from 500-650 nm, where the SOLSPEC is -1.3% lower than MODTRAN 3.5. Comparison of the SCIAMACHY solar spectrum from channels 1 to 4 (- re-calibrated by the University of Bremen -) with MODTRAN 3.5 indicates an agreement of +0.2% in the visible spectral range (435-585 nm). With this calibration, the SCIAMACHY solar spectrum is congruent with the balloon observations (-1%) in the 316.7-370 nm wavelength range, but both are up to -5%/-3% smaller than MODTRAN 3.5 and SOLSPEC, respectively. In agreement with findings of Skupin et al. (2002) our study emphasizes that the present ESA SCIAMACHY level 1 calibration is systematically +15% larger in the considered wavelength intervals when compared to all available other solar irradiance measurements.

  5. Influence of Extraterrestrial Radiation on Radiation Portal Monitors

    SciTech Connect

    Keller, Paul E.; Kouzes, Richard T.

    2009-06-01

    Cosmic radiation and solar flares can be a major source of background radiation at the Earth’s surface. This paper examines the relationship between extraterrestrial radiation and the detectable background in radiation portal monitors used for homeland security applications. Background radiation data from 13 radiation portal monitor facilities are examined and compared against external sources of data related to extraterrestrial radiation, including measurements at neutron monitors located at 53 cosmic-ray observatories around the Earth, four polar orbiting satellites, three geostationary satellites, ground-based geomagnetic field data from observatories around the Earth, a solar magnetic index, solar radio flux data, and sunspot activity data. Four-years (January 2003 through December 2006) of data are used in this study, which include the latter part of Solar Cycle 23 as solar activity was on the decline. The analysis shows a significant relationship between some extraterrestrial radiation and the background detected in the radiation portal monitors. A demonstrable decline is shown in the average gamma ray and neutron background at the radiation portal monitors as solar activity declined over the period of the study.

  6. Investigating ocean surface solar irradiance using Nimbus-7 Earth Radiation Budget data

    NASA Technical Reports Server (NTRS)

    Chertock, Beth; Frouin, Robert

    1989-01-01

    A new estimation technique is introduced, using a surface solar irradiance database with advanced climate monitoring capabilities. Incorporating the Nimbus-7 Earth Radiation Budget (ERB) planetary albedo data obtained from wide-field-of-view radiometer measurements, the new solar irradiance model uses plane-parallel theory and assumes the isotropy of radiance reflected by the clouds and ocean surface. A brief description of the data, a treatment of the model verification, and a discussion of surface solar irradiance variability are presented. The results demonstrate the model's sensitivity to large-scale seasonal and interannual phenomena. A summary of the investigation is also presented, along with a perspective on potential uses and future development.

  7. Simulation Study of Effects of Solar Irradiance and Sea Surface Temperature on Monsoons and Global Circulation

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Walker, G. K.; Mehta, V.; Lau, W. K.-M.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    A recent version of the GEOS 2 GCM was used to isolate the roles of the annual cycles of solar irradiation and/or sea-surface temperatures (SSTs) on the simulated circulation and rainfall. Four 4-year long integrations were generated with the GCM. The first integration, called Control Case, used daily-interpolated SSTs from a 30 year monthly SST climatology that was obtained from the analyzed SST-data, while the solar irradiation at the top of the atmosphere was calculated normally at hourly intervals. The next two cases prescribed the SSTs or the incoming solar irradiance at the top of the atmosphere at their annual mean values, respectively while everything else was kept the same as in the Control Case. In this way the influence of the annual cycles of both external forcings was isolated.

  8. Protosolar Irradiation in the Early Solar System: Clues from Lithium and Boron Isotopes

    E-print Network

    Liu, Ming-Chang; Alexander, Conel M O'D; Lee, Typhoon

    2011-01-01

    We report Li and B isotopic compositions of 10 Spinel-HIBonite spherules (SHIBs) separated from the Murchison meteorite, in order to understand their irradiation history in the early Solar System. The extremely low Be concentrations in SHIBs preclude detection of extinct 10Be, but instead allow for a search of the original Li and B isotopic ratios of the grains, as these isotopes are sensitive indicators for irradiation. We found that some of the SHIBs carried sub-chondritic 7Li/6Li and supra-chondritic 10B/11B ratios. Considering two possible irradiation scenarios that could have occurred in the early Solar System, irradiation of hibonite solids followed by addition of isotopically normal Li and B seems to be the most plausible explanation for the observed Li and B isotope ratios.

  9. Distribution of solar irradiance on inclined surfaces caused by moving clouds

    NASA Astrophysics Data System (ADS)

    Tomson, Teolan

    2015-04-01

    The distribution of solar irradiance in shadows of discrete (broken) clouds differs from the distribution calculated for inclined surfaces on the basis of traditional transposition models and changes fast. This phenomenon is studied in this paper. For calculations of dynamic distributions of irradiance on inclined surfaces, a formal point source of direct radiation near the real position of the sun is defined as the source of the "imaginable radiation." This notion is used to create a one-dimensional (1D) simulation model, which allows the fast-changing distribution of irradiance to be calculated. In general, the coincidence of calculated and measured irradiance on inclined surfaces is good. The paper also shows how the current value of the diffuse component of solar radiation can be derived from measurements of total radiation in four differently tilted planes.

  10. Solar Extreme Ultraviolet and X-ray Irradiance Measurements for Thermosphere and Ionosphere Studies (Invited)

    NASA Astrophysics Data System (ADS)

    Woods, T. N.; Caspi, A.; Chamberlin, P. C.; Eparvier, F. G.; Jones, A. R.; Sojka, J. J.; Solomon, S. C.; Viereck, R. A.

    2013-12-01

    The solar extreme ultraviolet (EUV: 10-120 nm) and soft X-ray (SXR: 0.1-10 nm) radiation is critical energy input for Earth's upper atmosphere above 80 km as a driver for photochemistry, ionosphere creation, temperature structure, and dynamics. Understanding the solar EUV and X-ray variations and their influences on Earth's atmosphere are important for myriad of space weather applications. The solar EUV and SXR spectral irradiances are currently being measured by NASA's Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) Solar EUV Experiment (SEE), NASA's Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE), and NOAA's GOES X-Ray Sensor (XRS) and EUV Sensor (EUVS). The solar irradiance varies on all time scales, ranging from seconds to hours from solar flare events, to days from 27-day solar rotation, and to years and longer from 11-year solar cycle. The amount of variation is strongly wavelength dependent with smaller ~50% solar cycle variations seen in the EUV for transition region emissions and larger factor of 10 and more variations seen in the SXR for coronal emissions. These solar irradiance observations are expected to be continued and to overlap with NASA's future Global-scale Observations of the Limb and Disk (GOLD) and Ionospheric Connection (ICON) missions that focus on the study of the thermosphere and ionosphere. These current measurements are only broad band in the SXR, but there are plans to have new spectral SXR measurements from CubeSat missions that may also overlap with the GOLD and ICON missions.

  11. Analysis of Solar Spectral Irradiance Measurements from the SBUV/2-Series and the SSBUV Instruments

    NASA Technical Reports Server (NTRS)

    Cebula, Richard P.; DeLand, Matthew T.; Hilsenrath, Ernest

    1997-01-01

    The NOAA-9 SBEV/2 instrument has made the first regular measurements ot solar UV activity over a complete solar cycle, beginning in March 1985 and continuing as of this writing. The NOAA-9 solar irradiance data set includes the minimum between Cycles 21-22 and the current minimum at the end of Cycle 22. Although overall solar activity is low during these periods, 27-day rotational modulation is frequently present. The episode of 13-day periodicity observed during September 1994 - March 1995 shows that phenomena previously associated with high levels of solar activity can occur at any point in the solar cycle. The 205 nm irradiance and Mg II index measured by NOAA-9 showed very similar behavior during the Cycle 21-22 minimum in 1985-1986, when 27-day periodicity dominated short-term solar variations, but behaved differently in 1994-1995 during the episode of 13-day periodicity. We plan further investigations into the physical causes of this result, since it affects the extent to which the Mg II index is an accurate proxy for 205 nm irradiance variations during such episodes. The NOAA-9 Mg II data are available.

  12. The MAVEN Extreme Ultraviolet Monitor: Providing Solar EUV Irradiances for Mars Atmospheric Studies

    NASA Astrophysics Data System (ADS)

    Eparvier, F. G.; Chamberlin, P. C.; Thiemann, E.; Woods, T. N.

    2014-12-01

    The extreme ultraviolet (EUV) solar irradiance is one of the primary energy sources into the Mars atmosphere. Photons in this wavelength range heat, dissociate, and ionize the constituents of the upper atmosphere, hence knowledge of the solar irradiance is vital in determining not only the state of the planet's atmosphere, but its variability and potential for atmospheric escape. The solar EUV irradiance varies on all timescales and is the result of the highly variable activity on the Sun. During the primary mission of the Mars Atmosphere Volatile Evolution Mission (MAVEN), the planet will be on a different side of the Sun than the Earth and will therefore be subjected to potentially very different irradiances than the standard Earth-based monitors can capture, particularly for short timescale variations such as on daily (active region evolution) or sub-daily (flares) scales. The EUV monitor on MAVEN measures the solar input to the Mars atmosphere with three broadband radiometers at 121-122 nm (H Ly-?), 17-22 nm, and 0-6 nm, capturing solar transition region, coronal, and flaring emissions. The EUV measurements will be at a 1-second cadence. The broadband measurements can be used as direct indicators of the timing and magnitude of solar irradiance variations. The EUV data will also be combined with interpolated Earth-based measurements using a proxy model to generate a full irradiance spectrum from 0-190 nm in1-nm bins at a 1-minute cadence for use in Mars atmospheric studies. This paper will present the EUV monitor measurements and data products and the synergies with the other MAVEN instruments and atmospheric studies.

  13. Irradiation and Measurement of GaAs-Based Solar Cells at Low Intensity, Low Temperature (LILT)

    Microsoft Academic Search

    S. Messenger; J. Tischler; M. Imaizumi; R. Harris

    This paper presents measurement and analysis of single junction GaAs and triple junction InGaP\\/GaAs\\/Ge solar cells after irradiation under low temperature and low intensity (LILT) conditions. The goal of these experiments was to quantify any annealing affects that might emerge after irradiation at low temperature and subsequent measurement after room temperature anneal. This is an important consideration for facilities that

  14. Annealing of GaAs solar cells damaged by electron irradiation

    Microsoft Academic Search

    G. H. Walker; E. J. Conway

    1978-01-01

    Measurements of thermal annealing of GaAlAs\\/GaAs solar cells damaged by 1 MeV electron irradiation are reported, and the magnitude of the short-circuit current recovery is discussed. The damaged cells are annealed in a vacuum at 200 C. A cell irradiated at 10 to the 13th power electrons per sq cm recovers all its lost short-circuit current after 15 hours of

  15. Electron and proton irradiation-induced degradation of epitaxial InP solar cells

    Microsoft Academic Search

    R. J. Walters; S. R. Messenger; H. L. Cotal; G. P. Summers; E. A. Burke

    1996-01-01

    The degradation of epitaxial, shallow homojunction n+p InP solar cells under 1 MeV electron and 3 MeV proton irradiation is presented. The data measured under 3 MeV proton irradiation are analyzed in terms of displacement damage dose which is the product of the particle fluence and the calculated non-ionizing energy loss (NIEL)[1]. A characteristic proton degradation curve is derived from

  16. Ray tracing algorithm for accurate solar irradiance prediction in urban areas.

    PubMed

    Vitucci, Enrico M; Falaschi, Federico; Degli-Esposti, Vittorio

    2014-08-20

    A ray tracing algorithm has been developed to model solar radiation interaction with complex urban environments and, in particular, its effects, including the total irradiance on each surface and overall dissipated power contribution. The proposed model accounts for multiple reflection and diffuse scattering interactions and is based on a rigorous theory, so that the overall power balance is satisfied at the generic surface element. Such approach is validated against measurements in the present work in simple reference scenarios. The results show the importance of multiple-bounce interactions and diffuse scattering to obtain reliable solar irradiance and heat dissipation estimates in urban areas. PMID:25321121

  17. The solar ultraviolet spectral irradiance monitor (SUSIM) experiment on board the Upper Atmosphere Research Satellite (UARS)

    NASA Technical Reports Server (NTRS)

    Brueckner, G. E.; Edlow, K. L.; Floyd, L. E., IV; Lean, J. L.; Vanhoosier, M. E.

    1993-01-01

    The state of solar ultraviolet irradiance measurements in 1978, when NASA requested proposals for a new generation of solar ultraviolet monitors to be flown on the Upper Atmosphere Research Satellite (UARS), is described. To overcome the radiometric uncertainties that plagued the measurements at this time, the solar ultraviolet spectral irradiance monitor (SUSIM) instrument design included in-flight calibration light sources and multichannel photometers. Both are aimed at achieving a maximum precision of the SUSIM measurements over a long period of time, e.g., one solar cycle. The design of the SUSIM-UARS instrument is compared with the original design specifications for the UARS instruments. Details including optical train, filters, detectors, and contamination precautions are described. Also discussed are the SUSIM-UARS preflight calibration and characterization, as well as the results of the inflight performance of the instrument during the first 3 months of operation. Finally, flight operations, observation strategy, and data reduction schemes are outlined.

  18. A comparison of solar irradiances measured by SBUV, SME, and rockets

    NASA Technical Reports Server (NTRS)

    Schlesinger, Barry M.; Heath, Donald F.

    1988-01-01

    In this paper, Solar Backscatter Ultraviolet (SBUV) measurements of solar irradiance and predictions from the Mg 280-nm index are compared with each other and with coincident Solar Mesosphere Explorer (SME) and rocket measurements. The SBUV irradiances show a systematic decrease with time not seen in the rocket measurements; a correction for this decrease is introduced. The scatter and overall structure in the SME spectra is 3-5 percent, of the order of or larger than most of the changes predicted by the Mg index. The corrected SBUV ratio and the Mg index prediction for it agree to within 1 percent. Such agreement supports a common origin for variations between solar maximum and minimum and those for individual rotations: the degree to which active regions cover the visible hemisphere of the sun.

  19. A new solar irradiance calibration from 3295 A to 8500 A derived from absolute spectrophotometry of VEGA

    Microsoft Academic Search

    G. W. Lockwood; H. Tueg; N. M. White

    1992-01-01

    By imaging sunlight diffracted by 20- and 30-micron diameter pinholes onto the entrance aperture of a photoelectric grating scanner, the solar spectral irradiance was determined relative to the spectrophotometric standard star Vega, observed at night with the same instrument. Solar irradiances are tabulated at 4 A increments from 3295 A to 8500 A. Over most of the visible spectrum, the

  20. Solar UV Irradiation Conditions on the Surface of Mars¶

    Microsoft Academic Search

    Györgyi Rontó; Attila Bérces; Helmut Lammer; Charles S. Cockell; Gregorio J. Molina-Cuberos; Manish R. Patel; Franck Selsis

    2003-01-01

    The UV radiation environment on planetary surfaces and within atmospheres is of importance in a wide range of scientific disciplines. ?1 Solar UV radiation is a driving force of chemical and organic evolution and serves also as a constraint in biological evolution. In this work we modeled the trans- mission of present and early solar UV radiation from 200 to

  1. Disinfection of Contaminated Water by Using Solar Irradiation

    Microsoft Academic Search

    Laurie F. Caslake; Daniel J. Connolly; Vilas Menon; Catriona M. Duncanson; Ricardo Rojas; Javad Tavakoli

    2004-01-01

    Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with

  2. The Absolute Solar Irradiance Spectrum at Solar Minimum Activity Measured by the SOLSPEC and SOL-ACES Spectrometers from 17 to 3000 nm Placed on Board the International Space Station

    Microsoft Academic Search

    Gerard Thuillier; David Bolsee; Gerhard Schmidtke; Werner Schmutz; Alexander Shapiro; Bernd Nikutowski

    2010-01-01

    Two instruments placed on the COLOMBUS laboratory on the International Space Station constitute a payload named SOLAR measuring the spectral solar irradiance from 17 to 3000 nm for solar, atmospheric and climatology physics for which the sun-climate connection also re-quires the precise and absolute knowledge of the solar spectral irradiance. Given the significant improvements in atmosphere, climate and solar modelling,

  3. The Sun as a variable star: Solar and stellar irradiance variations; Colloquium of the International Astronomical Union, 143rd, Boulder, CO, Jun. 20-25, 1993

    NASA Technical Reports Server (NTRS)

    Pap, Judit M. (editor); Froehlich, Claus (editor); Hudson, Hugh S. (editor); Tobiska, W. Kent (editor)

    1994-01-01

    Variations in solar and stellar irradiances have long been of interest. An International Astronomical Union (IAU) colloquium reviewed such relevant subjects as observations, theoretical interpretations, and empirical and physical models, with a special emphasis on climatic impact of solar irradiance variability. Specific topics discussed included: (1) General Reviews on Observations of Solar and Stellar Irradiance Variability; (2) Observational Programs for Solar and Stellar Irradiance Variability; (3) Variability of Solar and Stellar Irradiance Related to the Network, Active Regions (Sunspots and Plages), and Large-Scale Magnetic Structures; (4) Empirical Models of Solar Total and Spectral Irradiance Variability; (5) Solar and Stellar Oscillations, Irradiance Variations and their Interpretations; and (6) The Response of the Earth's Atmosphere to Solar Irradiance Variations and Sun-Climate Connections.

  4. Irradiation-induced degradation of amorphous silicon solar cells in space

    Microsoft Academic Search

    A. Klaver

    2007-01-01

    Solar cells are the prime power supply for satellites in space. Space is, however, a hostile environment for electronic devices, such as solar cells: in space the devices are subjected to large temperature cycles, atomic oxygen, space dust, meteorites, and high-energy charged-particle irradiation. In this thesis we present the development of a model with which the EOL-performance of hydrogenated amorphous

  5. Irradiance characteristics and optimization design of a large-scale solar simulator

    Microsoft Academic Search

    Qinglong Meng; Yuan Wang; Linhua Zhang

    2011-01-01

    A new economical large-scale multiple-lamp solar simulator was designed and constructed to provide a test platform for the simulation of solar radiation at the earth’s surface. The light source and fabrication of the simulator is described. Measurement of the irradiance indicates that the multiple-lamp simulator conforms to Class B of the ASTM (American Society for Testing and Materials) and IEC

  6. Fenton degradation of 4-chlorophenol contaminated water promoted by solar irradiation

    Microsoft Academic Search

    Wen S. Kuo; Li N. Wu

    2010-01-01

    The degradation of 4-chlorophenol (4-CP) contaminated water by Fenton process with or without solar irradiation assistance were investigated. It was found that the COD degradation and mineralization efficiency of 4-CP were more than 90% when a 30min treatment of solar photo-Fenton oxidation process was applied and under an optimum [H2O2]0\\/[Fe2+]0 ratio of 40, the COD degradation and mineralization efficiency increased

  7. Modeling Solar Spectral Irradiance and Total Magnetic Flux Using Sunspot Areas

    Microsoft Academic Search

    Dora G. Preminger; Stephen R. Walton

    2006-01-01

    We show that daily sunspot areas can be used in a simple, single parameter model to reconstruct daily variations in several\\u000a other solar parameters, including solar spectral irradiance and total magnetic flux. The model assumes that changes in any\\u000a given parameter can be treated mathematically as the response of the system to the emergence of a sunspot. Using cotemporal\\u000a observational

  8. Limitation of Ground-based Estimates of Solar Irradiance Due to Atmospheric Variations

    NASA Technical Reports Server (NTRS)

    Wen, Guoyong; Cahalan, Robert F.; Holben, Brent N.

    2003-01-01

    The uncertainty in ground-based estimates of solar irradiance is quantitatively related to the temporal variability of the atmosphere's optical thickness. The upper and lower bounds of the accuracy of estimates using the Langley Plot technique are proportional to the standard deviation of aerosol optical thickness (approx. +/- 13 sigma(delta tau)). The estimates of spectral solar irradiance (SSI) in two Cimel sun photometer channels from the Mauna Loa site of AERONET are compared with satellite observations from SOLSTICE (Solar Stellar Irradiance Comparison Experiment) on UARS (Upper Atmospheric Research Satellite) for almost two years of data. The true solar variations related to the 27-day solar rotation cycle observed from SOLSTICE are about 0.15% at the two sun photometer channels. The variability in ground-based estimates is statistically one order of magnitude larger. Even though about 30% of these estimates from all Level 2.0 Cimel data fall within the 0.4 to approx. 0.5% variation level, ground-based estimates are not able to capture the 27-day solar variation observed from SOLSTICE.

  9. The Impact of Different Absolute Solar Irradiance Values on Current Climate Model Simulations

    NASA Technical Reports Server (NTRS)

    Rind, David H.; Lean, Judith L.; Jonas, Jeffrey

    2014-01-01

    Simulations of the preindustrial and doubled CO2 climates are made with the GISS Global Climate Middle Atmosphere Model 3 using two different estimates of the absolute solar irradiance value: a higher value measured by solar radiometers in the 1990s and a lower value measured recently by the Solar Radiation and Climate Experiment. Each of the model simulations is adjusted to achieve global energy balance; without this adjustment the difference in irradiance produces a global temperature change of 0.48C, comparable to the cooling estimated for the Maunder Minimum. The results indicate that by altering cloud cover the model properly compensates for the different absolute solar irradiance values on a global level when simulating both preindustrial and doubled CO2 climates. On a regional level, the preindustrial climate simulations and the patterns of change with doubled CO2 concentrations are again remarkably similar, but there are some differences. Using a higher absolute solar irradiance value and the requisite cloud cover affects the model's depictions of high-latitude surface air temperature, sea level pressure, and stratospheric ozone, as well as tropical precipitation. In the climate change experiments it leads to an underestimation of North Atlantic warming, reduced precipitation in the tropical western Pacific, and smaller total ozone growth at high northern latitudes. Although significant, these differences are typically modest compared with the magnitude of the regional changes expected for doubled greenhouse gas concentrations. Nevertheless, the model simulations demonstrate that achieving the highest possible fidelity when simulating regional climate change requires that climate models use as input the most accurate (lower) solar irradiance value.

  10. The Influence of Total Solar Irradiance on Climate

    NASA Astrophysics Data System (ADS)

    Cubasch, U.; Voss, R.

    2000-11-01

    To estimate the effect of the solar variability on the climate, two estimates of the solar intensity variations during the last three centuries have been used as forcing in numerical simulations. The model employed to carry out the experiments was the same coupled global ocean-atmosphere model used in a number of studies to assess the effect of the anthropogenic greenhouse gases on climate. The near surface temperature and the tropospheric temperature distribution shows a clear response to the variability of the solar input. Even the thermohaline circulation reacts on the large amplitudes in the forcing. In the stratosphere, the response pattern is similar as in the observations, however, the 11-year cycle found in the forcing data does not excite an appreciable response. This might be due to the missing parameterisation of the increase in the UV-radiation at the solar cycle maximum and the connected increase of the stratospheric ozone concentration.

  11. Low temperature quantum efficiency measurements on irradiated multijunction solar cells

    Microsoft Academic Search

    S. R. Messenger; J. H. Warner; P. P. Jenkins; R. J. Walters; J. R. Lorentzen

    2008-01-01

    This paper presents quantum efficiency (QE) measurements and analyses on monolithic triple junction (3J) InGaP\\/GaAs\\/Ge solar cells under both room (300K) and low temperature (130K) conditions. In measuring the quantum efficiency of multijunction solar cells, one must be careful to use the proper bias conditions to isolate the subcell of interest. This may be achieved by using external light sources

  12. New developments in solar irradiance proxies for operational space weather

    Microsoft Academic Search

    W. Kent Tobiska

    2002-01-01

    Six new solar proxies have been developed in the past two years in support of a sec- ond-generation forecasting capability. These proxies help characterize the energy input into op- erational space physics models. In addition to hourly-to-daily forecasts that produce a full solar spectrum used in numerical atmospheric and ionospheric models relevant to climatological stud- ies, the E10.7 index is

  13. Proposed reference irradiance spectra for solar energy systems testing

    Microsoft Academic Search

    C. A. Gueymard; D. Myers; K. Emery

    2002-01-01

    In 1982, the American Society for Testing and Materials (ASTM) adopted consensus standard solar terrestrial spectra (ASTM E891-82, E892-82) to provide standard spectra for photovoltaic (PV) performance applications. These spectra have been also used for other applications such as solar energy systems, fenestration, and materials degradation. These reference spectra were recomputed and the standards revised in 1987. The International Standards

  14. Co60 gamma-ray and electron irradiation damage of GaAs single crystals and solar cells

    Microsoft Academic Search

    M. Yamaguchi; C. Amano

    1983-01-01

    The present investigation is concerned with the damage suffered by GaAs solar cells when they are exposed to irradiation involving Co-60 gamma rays and high-energy electrons (0.8-4 MeV). The AlGaAs-GaAs heteroface solar cell, fabricated by liquid phase epitaxy processes, was employed in the studies. Isochronal annealings of the solar cell after the irradiation were carried out in vacuum for 10

  15. The Solar Spectral Irradiance Measured on Board the International Space Station and the Picard Spacecraft

    NASA Astrophysics Data System (ADS)

    Thuillier, G. O.; Bolsee, D.; Schmidtke, G.; Schmutz, W. K.

    2011-12-01

    On board the International Space Station, the spectrometers SOL-ACES and SOLSPEC measure the solar spectrum irradiance from 17 to 150 nm and 170 to 2900 nm, respectively. On board PICARD launched on 15 June 2010, the PREMOS instrument consists in a radiometer and several sunphotometers operated at several fixed wavelengths. We shall present spectra at different solar activity levels as well as their quoted accuracy. Comparison with similar data from other missions presently running in space will be shown incorporating the PREMOS measurements. Some special solar events will be also presented and interpreted.

  16. A method to measure the broadband longwave irradiance in the terrestrial direct solar beam

    NASA Astrophysics Data System (ADS)

    Reda, Ibrahim; Konings, Jörgen; Xie, Yu

    2015-07-01

    Shortwave radiometers such as pyranometers, pyrheliometers, photovoltaic cells, and longwave radiometers such as pyrgeometers are calibrated with traceability to consensus References, which are maintained by Absolute Cavity Radiometers (ACRs) and the World InfraRed Standard Group (WISG), respectively. Since the ACR is an open cavity with no window, and was developed to measure the extended broadband spectrum of the terrestrial direct solar beam irradiance, then there would be discrepancy in calibrating the shortwave radiometers because of their limited spectral band. On the other hand, pyrgeometers are calibrated during the nighttime only, because no consensus reference has yet been established for the daytime longwave irradiance. This article describes a method to measure the broadband longwave irradiance in the terrestrial direct solar beam from 3 ?m to 50 ?m. The method might be used in developing calibration methods to address the mismatch between the broadband ACR and shortwave radiometers, and the lack of a daytime reference for pyrgeometer calibration. We used the described method to measure the irradiance from sunrise to sunset; the irradiance varied from approximately 1 W m-2 to 16 W m-2 with an estimated uncertainty of 1.46 W m-2, for a solar zenith angle range from 80° to 16°, respectively.

  17. Thermal recovery of degraded space silicon solar cells due to large fluence irradiation

    Microsoft Academic Search

    Tadashi HISAMATSU; Sumio MATSUDA; Tetsuya NAKAO; Yusuke MATSUMOTO; Stephen J. TAYLOR; M. Yamaguchi

    1997-01-01

    As a part of analysis of “the anomalous degradation behavior” which is found in large-fluence-irradiated Si solar cells, thermal recovery of damaged cells are investigated. The cells show partial recovery at relatively low temperature such as 200°C and 350°C, which is consistent with removal of the divacancy

  18. Photon Induced Degradation of Electron and Proton Irradiated Silicon Solar Cells

    Microsoft Academic Search

    R. L. Crabb

    1973-01-01

    Infra red photon-induced electrical performance degradation of several types of commonly used silicon solar cells has been studied with respect to 1 Mev electron fluence dependance, photon intensity, dopant atom type and concentration, and silicon growth (crucible grown or float zone). Proton irradiated cells have also been studied. Laboratory electronphoton degradation data is compared with flight data from the ESRO

  19. Total Solar Irradiance Calibration Transfer Experiment/TIM Frequently Asked Questions

    E-print Network

    Mojzsis, Stephen J.

    of space exploration through our expertise in science, engineering, mission operations, and data management is the purpose of the TCTE mission? The Total Solar Irradiance Calibration Transfer Experiment (TCTE climate data record, which began from space in 1978, and is used to determine the sensitivity of the Earth

  20. THE EFFECT OF THE TRANSIT OF VENUS ON ACRIM'S TOTAL SOLAR IRRADIANCE MEASUREMENTS: IMPLICATIONS FOR TRANSIT

    E-print Network

    Schneider, Glenn

    intrinsically limit such transit obser- vations. During the Venus transit, which lasted $5.5 hr, the planet headinggs: planets and satellites: individual (Venus) -- techniques: photometric 1. INTRODUCTION SinceTHE EFFECT OF THE TRANSIT OF VENUS ON ACRIM'S TOTAL SOLAR IRRADIANCE MEASUREMENTS: IMPLICATIONS

  1. Satellite-Derived Surface Radiation Budget over the Algerian area. Estimation of Downward Solar Irradiance

    Microsoft Academic Search

    R. Aboura; A. Lansari

    Downward surface solar irradiance received at ground, is an important component of the energy budget of ground surface. Indirect derivations of this parameter are common on the absence of direct measurements with reliable instruments. Our estimation is based on satellites observations. This paper presents development work on a tool for modelling the downward radiation received at ground. At first, this

  2. Remote sensing of surface solar irradiance with corrections for 3-D cloud effects

    E-print Network

    Jones, Charles

    resolution of satellite sensors increases, the effects from spatially inhomogeneous cloud fields become more developed computation methods for estimating both down- ward and net surface solar irradiance from satellite- national Satellite Cloud Climatology Project (ISCCP, Bishop & Rossow, 1991) and from the Earth Radiation

  3. Effect of manual tilt adjustments on incident irradiance on fixed and tracking solar panels

    Microsoft Academic Search

    William David Lubitz

    2011-01-01

    Hourly typical meteorological year (TMY3) data was utilized with the Perez radiation model to simulate solar radiation on fixed, azimuth tracking and two axis tracking surfaces at 217 geographically diverse temperate latitude sites across the contiguous United States of America. The optimum tilt angle for maximizing annual irradiation on a fixed south-facing panel varied from being equal to the latitude

  4. Coupled noble gas-hydrocarbon evolution of the early Earth atmosphere upon solar UV irradiation

    E-print Network

    Paris-Sud XI, Université de

    Coupled noble gas-hydrocarbon evolution of the early Earth atmosphere upon solar UV irradiation E, the relationship between noble gas photoionization and organic photochemistry has been investigated from efficient that other ionized noble gases trapping and (2) results in a significant enrichment of heavy xenon

  5. SAS Honors Seminar 256: Extraterrestrial Life

    E-print Network

    Baker, Andrew J.

    SAS Honors Seminar 256: Extraterrestrial Life 11/29/2011 #12; Reading for Thursday Review for Astrobiological Research The Ethics of Terraforming The History of SETI The Media's Portrayal of Extraterrestrial

  6. The dependence of the surface solar irradiance on cloud and aerosol

    NASA Astrophysics Data System (ADS)

    kim, Yun Mi; Kim, Jhoon; Cho, Hi Ku; Lee, Yun Gon; Koo, Ja Ho; Kim, Young Joon

    2009-03-01

    To quantify radiative forcing of aerosol and to investigate the dependence of the horizontal UV, visible and NIR on total optical depth (TOD) and cloudiness, narrowband surface solar irradiances were measured and analyzed for direct and diffuse component. A MFRSR (Multifilter Rotating Shadowband Ratiometer) was used to measure the global, direct and diffuse solar irradiances atone broadband of 391-955 nm and 6 narrowband channels of 412.8, 495.2, 611.9, 672.2, 869, 936.6 nm for a year from Jan. to Dec. in 2006 at Yonsei University in Seoul and a UV-MFRSR was used to measure irradiance at 7 narrowband channels of 299.1, 304.5, 310.7, 317.1, 323.8, 331.3, 367.4 nm in UV range during 7 months at the same location with the MFRSR.

  7. On the possible influence of extraterrestrial volatiles on Earth's climate and the origin of the oceans

    Microsoft Academic Search

    David Deming

    1999-01-01

    A consideration of observational and circumstantial evidence suggests that Earth may be subject to high influx rates (1011–1012 kg\\/yr) of extraterrestrial-sourced volatile elements (carbon, hydrogen, oxygen, nitrogen) derived from comets or other primitive solar-system material. The total extraterrestrial influx rate may be four to five orders of magnitude greater than previously thought, large enough to account for today's total near-surface

  8. Comparison of ACRIM and PMOD Total Solar Irradiance composites time series during solar cycles 21 - 23

    NASA Astrophysics Data System (ADS)

    Willson, R. C.

    2005-05-01

    The set of contiguous, redundant and overlapping total solar irradiance (TSI) observations made by satellite experiments since late 1978 enables construction of continuous composite TSI time series. A multi-decadal TSI composite requires establishment of the relationship between ACRIM1 and ACRIM2 results across the two year gap between them using one of two overlapping data sets: the Nimbus7/ERB or ERBS/ERBE. Two TSI composites have been published, the ACRIM using the Nimbus7/ERB comparisons [Willson & Mordvinov, 2003] and the PMOD using the ERBS/ERBE comparisons [Frohlich & Lean, 1998]. The ACRIM composite uses unaltered published results from a subset of the satellite TSI data. The most significant feature of the ACRIM composite for climate change is an upward trend of 0.04 (+/- 0.01) % per decade between activity minima during solar cycles 21-23. The PMOD composite uses a different subset of the same satellite TSI data, modifying some results using TSI proxy models as a guide. There are a number of differences between the PMOD and ACRIM composites but the most important is the absence of a significant trend between minima in the PMOD. The trend difference is the direct result of the choice of Nimbus7/ERB or ERBS/ERBE to relate ACRIM1 and ACRIM2 results across the ACRIM gap. The lack of a minima-to-minima trend in composites based on the ERBS/ERBE can be shown to be an artifact of uncorrected degradation during the `gap'. The significance of the ACRIM composite trend will be explored in the context of the traceability of the constituent TSI data sets. Other differences between the ACRIM and PMOD composites result from PMOD's use of TSI proxy models to justify altering published results of ACRIM1 and Nimbus7/ERB. TSI regression (proxy) models based on chromospheric spectral features are not competitive in accuracy, precision or traceability with satellite TSI observations and are therefore may be expected to cause spurious effects when used in the construction of TSI composites. The TSI record has been sustained by overlapping, redundant experiments using their level of measurement precision to sustain longer term traceability. This TSI monitoring strategy is essential for continuity in the future because the uncertainty of current satellite sensors (~ 0.1 %) is an order of magnitude too large to detect subtle long term TSI variations of potential climate change significance. [Willson, R.C., A. V. Mordvinov, JGRL 30, pp. 1199-1202, 2003, Frohlich C., J. Lean, JGRL 25, pp. 4377-4380, 1998

  9. The UV-A and visible solar irradiance spectrum: inter-comparison of absolutely calibrated, spectrally medium resolution solar irradiance spectra from balloon- and satellite-borne measurements

    NASA Astrophysics Data System (ADS)

    Gurlit, W.; Bösch, H.; Bovensmann, H.; Burrows, J. P.; Butz, A.; Camy-Peyret, C.; Dorf, M.; Gerilowski, K.; Lindner, A.; Noël, S.; Platt, U.; Weidner, F.; Pfeilsticker, K.

    2005-07-01

    Within the framework of the ENVISAT/-SCIAMACHY satellite validation, solar irradiance spectra are absolutely measured at moderate resolution in the UV/visible spectral range (in the UV from 316.7-418 nm and the visible from 400-652 nm at a full width half maximum resolution of 0.55 nm and 1.48 nm, respectively) from aboard the azimuth-controlled LPMA/DOAS balloon gondola at around 32 km balloon float altitude. After accounting for the atmospheric extinction due to Rayleigh scattering and gaseous absorption (O3 and NO2), the measured solar spectra are compared with previous observations. Our solar irradiance spectrum perfectly agrees within +0.03% with the re-calibrated Kurucz et al. (1984) solar spectrum (Fontenla et al., 1999, called MODTRAN 3.7) in the visible spectral range (415-650 nm), but it is +2.1% larger in the (370-415 nm) wavelength interval, and -4% smaller in the UV-A spectral range (316.7-370 nm), when the Kurucz spectrum is convolved to the spectral resolution of our instrument. Similar comparisons of the SOLSPEC (Thuillier et al., 1997, 1998a, b) and SORCE/SIM (Harder et al., 2000) solar spectra with MODTRAN 3.7 confirms our findings with the values being -0.5%, +2%, and -1.4% for SOLSPEC -0.33%, -0.47%, and -6.2% for SORCE/SIM, respectively. Comparison of the SCIAMACHY solar spectrum from channels 1 to 4 (- re-calibrated by the University of Bremen -) with MODTRAN 3.7 indicates an agreement within -0.4% in the visible spectral range (415-585 nm), -1.6% within the 370-415 nm, and -5.7% within 325-370 nm wavelength interval, in agreement with the results of the other sensors. In agreement with findings of Skupin et al. (2002) our study emphasizes that the present ESA SCIAMACHY level 1 calibration is systematically +15% larger in the considered wavelength intervals when compared to all available other solar irradiance measurements.

  10. Analysis of Solar Spectral Irradiance Measurements from the SBUV/2-Series and the SSBUV Instruments

    NASA Technical Reports Server (NTRS)

    Cebula, Richard P.; DeLand, Matthew T.; Hilsenrath, Ernest

    1997-01-01

    During this period of performance, 1 March 1997 - 31 August 1997, the NOAA-11 SBUV/2 solar spectral irradiance data set was validated using both internal and external assessments. Initial quality checking revealed minor problems with the data (e.g. residual goniometric errors, that were manifest as differences between the two scans acquired each day). The sources of these errors were determined and the errors were corrected. Time series were constructed for selected wavelengths and the solar irradiance changes measured by the instrument were compared to a Mg II proxy-based model of short- and long-term solar irradiance variations. This analysis suggested that errors due to residual, uncorrected long-term instrument drift have been reduced to less than 1-2% over the entire 5.5 year NOAA-11 data record. Detailed statistical analysis was performed. This analysis, which will be documented in a manuscript now in preparation, conclusively demonstrates the evolution of solar rotation periodicity and strength during solar cycle 22.

  11. Solar Irradiances Measured using SPN1 Radiometers: Uncertainties and Clues for Development

    SciTech Connect

    Badosa, Jordi; Wood, John; Blanc, Philippe; Long, Charles N.; Vuilleumier, Laurent; Demengel, Dominique; Haeffelin, Martial

    2014-12-08

    The fast development of solar radiation and energy applications, such as photovoltaic and solar thermodynamic systems, has increased the need for solar radiation measurement and monitoring, not only for the global component but also the diffuse and direct. End users look for the best compromise between getting close to state-of-the-art measurements and keeping capital, maintenance and operating costs to a minimum. Among the existing commercial options, SPN1 is a relatively low cost solar radiometer that estimates global and diffuse solar irradiances from seven thermopile sensors under a shading mask and without moving parts. This work presents a comprehensive study of SPN1 accuracy and sources of uncertainty, which results from laboratory experiments, numerical modeling and comparison studies between measurements from this sensor and state-of-the art instruments for six diverse sites. Several clues are provided for improving the SPN1 accuracy and agreement with state-of-the-art measurements.

  12. SAS Honors Seminar 256: Extraterrestrial Life

    E-print Network

    Baker, Andrew J.

    SAS Honors Seminar 256: Extraterrestrial Life 11/22/2011 #12; Where are the Pioneers on discovery of extraterrestrial (un)intelligence McKay (2009) & Bailey (2011) ­ deliberately terraforming Research The History of SETI The Media's Portrayal of Extraterrestrial Life and its Influence on Public

  13. Evidence for High-Energy Extraterrestrial Neutrinos

    E-print Network

    Woschnagg, Kurt

    Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector IceCube Collaboration, however, consistent with generic predictions for an additional component of extraterrestrial origin. H igh of an extraterrestrial source (3). Although that analysis had some sensitivity to neutrino events of all flavors above 1

  14. ADVANCING THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE

    E-print Network

    ADVANCING THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE Jill Tarter SETI Institute 515 N. Whisman ­ Space Sciences Lab, UC Berkeley #12;Advancing the Search for Extraterrestrial Intelligence Executive for extraterrestrial intelligence. Today SETI falls under the umbrella of astrobiology, a suite of cross

  15. A Program of Photometric Measurements of Solar Irradiance Fluctuations from Ground-based Observations

    NASA Technical Reports Server (NTRS)

    Chapman, G. A.; Herzog, A. D.; Lawrence, J. K.; Walton, S. R.

    1990-01-01

    Photometric observations of the sun have been carried out at the San Fernando Observatory since early 1985. Since 1986, observations have been obtained at two wavelengths in order to separately measure the contributions of sunspots and bright facular to solar irradiance variations. Researchers believe that the contributions of sunspots can be measured to an accuracy of about plus or minus 30 ppm. The effect of faculae is much less certain, with uncertainties in the range of plus or minus 300 ppm. The larger uncertainty for faculae reflects both the greater difficulty in measuring the facular area, due to their lower contrast compared to sunspots, and the greater uncertainty in their contrast variation with viewing angle on the solar disk. Recent results from two separate photometric telescopes will be compared with bolometric observations from the active cavity radiometer irradiance monitor (ACRIM) that was on board the Solar Max satellite.

  16. Modelling the solar irradiance during the Maunder Minimum and the corresponding cooling

    SciTech Connect

    Garduno, R.; Mendoza, B.; Adem, J. [UNAM, Mexico City (Mexico)

    1996-12-31

    Expressions to compute the solar irradiance as a function of the sun rotation rate, sunspot number and solar cycle length, are deduced. They yield a solar irradiance dimmed by about 0.5% during the Maunder Minimum (1660-1720). This parameter is put in the Adem thermodynamic model as an external forcing to simulate the corresponding climate change. Another forcing used is the preindustrial level of atmospheric CO{sub 2} which reinforces the cooling. The model generates three internal feedbacks: cryosphere, cloudiness and water vapor. The output is a cooling of about 0.5 to 1 C, with respect to present climate, depending on the forcings and feedbacks included. These results agree well with those from other authors and with the few historical records.

  17. Effects of illumination and 60Co ?-ray irradiation on the electrical characteristics of porous silicon solar cells

    Microsoft Academic Search

    Ö. Tüzün; ?. Alt?ndal; ?. Oktik

    2008-01-01

    A new approach for hybrid metal–insulator–semiconductor (MIS) Si solar cells is adopted by Institute of Fundamental Problems for High Technology, Ukrainian Academy of Sciences. In order to interpret the effect of illumination and 60Co ?-ray radiation dose on the electrical characteristics of solar cells are studied at room temperature. Before the solar cells are subjected to stressed irradiation six different

  18. The sensitivity of calculated short-circuit currents to selected irradiance distributions and solar cell spectral responses

    Microsoft Academic Search

    J. S. Hartman; M. A. Lind; D. A. Chaudiere

    1982-01-01

    Calculations of normalized differences in solar cell short-circuit currents are reported for a variety of solar cell materials and illumination sources. All results were referenced to the cell response under a standard air mass 1.5 irradiance distribution. Each solar cell and source combination was evaluated for two candidate source normalization procedures. The first is a photon flux normalization technique in

  19. Changes in photochemically significant solar UV spectral irradiance as estimated by the composite Mg II index and scale factors

    NASA Technical Reports Server (NTRS)

    Deland, Matthew T.; Cebula, Richard P.

    1994-01-01

    Quantitative assessment of the impact of solar ultraviolet irradiance variations on stratospheric ozone abundances currently requires the use of proxy indicators. The Mg II core-to-wing index has been developed as an indicator of solar UV activity between 175-400 nm that is independent of most instrument artifacts, and measures solar variability on both rotational and solar cycle time scales. Linear regression fits have been used to merge the individual Mg II index data sets from the Nimbus-7, NOAA-9, and NOAA-11 instruments onto a single reference scale. The change in 27-dayrunning average of the composite Mg II index from solar maximum to solar minimum is approximately 8 percent for solar cycle 21, and approximately 9 percent for solar cycle 22 through January 1992. Scaling factors based on the short-term variations in the Mg II index and solar irradiance data sets have been developed to estimate solar variability at mid-UV and near-UV wavelengths. Near 205 nm, where solar irradiance variations are important for stratospheric photo-chemistry and dynamics, the estimated change in irradiance during solar cycle 22 is approximately 10 percent using the composite Mg II index and scale factors.

  20. Observed solar UV irradiance variations of importance to middle atmosphere energetics and photochemistry

    NASA Technical Reports Server (NTRS)

    London, Julius

    1994-01-01

    Absorption of solar UV irradiance in the spectral interval 120-420 nm is chiefly responsible for radiative heating and photodissociation of important atmospheric constituents (e.g., O2, O3, H2O, NO2, etc.) in the stratosphere, mesosphere, and lower thermosphere. Thus, the absolute value and time perturbations of the UV irradiance could significantly affect the energetics, photochemistry, and subsequent dynamics of these regions. Analysis of preliminary data from the SOLSTICE (UARS) observations for a period of 244 days (3 Oct 1991-2 Jun 1992) is discussed in this paper. The data provide mean daily values of the spectral distribution of the observed irradiances at 1-nm resolution and their solar rotation and semirotation variations. The average amplitudes of the 27-day irradiance oscillations for the 244-day data period were 5.7% at Lyman-alpha (121 nm), 1% at 200 nm, 0.5% at 210 nm, and generally less than 0.2% at wavelengths longer than 280 nm. The average amplitudes of 13.5-day oscillations were, by and large, about half of these values. Solar irradiance variations at 10.7 cm are highly correlated with those at Ly-alpha and other chromospheric emission lines (r = 0.7 to 0.8) and only moderately correlated with irradiances at wavelengths of 180-208 nm (r = 0.5). The correlation decreases as the source region of the irradiance gets closer to the base of the photosphere. At the 2-nm interval 279-281 nm, however, which contains the cores of the Mg II h and k lines, the correlation is again approximately 0.8.

  1. Evaluation of errors made in solar irradiance estimation due to averaging the Angstrom turbidity coefficient

    NASA Astrophysics Data System (ADS)

    Calinoiu, Delia-Gabriela; Stefu, Nicoleta; Paulescu, Marius; Trif-Tordai, Gavril?; Mares, Oana; Paulescu, Eugenia; Boata, Remus; Pop, Nicolina; Pacurar, Angel

    2014-12-01

    Even though the monitoring of solar radiation experienced a vast progress in the recent years both in terms of expanding the measurement networks and increasing the data quality, the number of stations is still too small to achieve accurate global coverage. Alternatively, various models for estimating solar radiation are exploited in many applications. Choosing a model is often limited by the availability of the meteorological parameters required for its running. In many cases the current values of the parameters are replaced with daily, monthly or even yearly average values. This paper deals with the evaluation of the error made in estimating global solar irradiance by using an average value of the Angstrom turbidity coefficient instead of its current value. A simple equation relating the relative variation of the global solar irradiance and the relative variation of the Angstrom turbidity coefficient is established. The theoretical result is complemented by a quantitative assessment of the errors made when hourly, daily, monthly or yearly average values of the Angstrom turbidity coefficient are used at the entry of a parametric solar irradiance model. The study was conducted with data recorded in 2012 at two AERONET stations in Romania. It is shown that the relative errors in estimating global solar irradiance (GHI) due to inadequate consideration of Angstrom turbidity coefficient may be very high, even exceeding 20%. However, when an hourly or a daily average value is used instead of the current value of the Angstrom turbidity coefficient, the relative errors are acceptably small, in general less than 5%. All results prove that in order to correctly reproduce GHI for various particular aerosol loadings of the atmosphere, the parametric models should rely on hourly or daily Angstrom turbidity coefficient values rather than on the more usual monthly or yearly average data, if currently measured data is not available.

  2. Solar irradiance and the development of endomycorrhizal green ash seedlings.

    PubMed

    Borges, R G; Chaney, W R

    1993-10-01

    We investigated the effects and interaction of four irradiances, 37, 53, 70 and 100% full sunlight, and the endomycorrhizae Glomus macrocarpum and Glomus fasciculatum on the development of seedlings of Fraxinus pennsylvanica Marsh. At all irradiances, mycorrhizal seedlings were taller and larger in diameter than nonmycorrhizal seedlings. Seedlings inoculated with G. macrocarpum showed the best height growth at 70% or less of full sunlight, whereas seedlings inoculated with G. fasciculatum grew best at 37 and 53% full sunlight. Leaf area was greatest in shaded seedlings and was enhanced by mycorrhizal inoculation. Shoot/root ratios were greater for mycorrhizal than for nonmycorrhizal seedlings. At intermediate light intensities, percent root length colonized was greatest, whereas the concentrations of soluble sugar and starch in roots were at intermediate levels. PMID:14969881

  3. Annealing results on low-energy proton-irradiated GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Kachare, R.; Anspaugh, B. E.; O'Meara, L.

    1988-01-01

    AlGaAs/GaAs solar cells with an approximately 0.5-micron-thick Al(0.85)Ga(0.15)As window layer were irradiated using normal and isotropic incident protons having energies between 50 and 500 keV with fluence up to 1 x 10 to the 12th protons/sq cm. The irradiated cells were annealed at temperatures between 150 and 300 C in nitrogen ambient. The annealing results reveal that significant recovery in spectral response at longer wavelengths occurred. However, the short-wavelength spectral response showed negligible annealing, irrespective of the irradiation energy and annealing conditions. This indicates that the damage produced near the AlGaAs/GaAs interface and the space-charge region anneals differently than damage produced in the bulk. This is explained by using a model in which the as-grown dislocations interact with irradiation-induced point defects to produce thermally stable defects.

  4. SPECTRAL SOLAR IRRADIANCE AND ITS ENTROPIC EFFECT ON EARTH'S CLIMATE

    E-print Network

    to the typical value of the entropy production rate associated with atmospheric latent heat process. Further. Reference herein to any specific commercial product, process, or service by trade name, trademark's entropy flux from the TOA incident solar radiation. Two extreme cases are examined by using Planck

  5. Direct solar spectral irradiance and transmittance measurements from 350 to 2500 nm.

    PubMed

    Kindel, B C; Qu, Z; Goetz, A F

    2001-07-20

    A radiometrically stable, commercially available spectroradiometer was used in conjunction with a simple, custom-designed telescope to make spectrally continuous measurements of solar spectral transmittance and directly transmitted solar spectral irradiance. The wavelength range of the instrument is 350-2500 nm and the resolution is 3-11.7 nm. Laboratory radiometric calibrations show the instrument to be stable to better than 1.0% over a nine-month period. The instrument and telescope are highly portable, can be set up in a matter of minutes, and can be operated by one person. A method of absolute radiometric calibration that can be tied to published top-of-the-atmosphere (TOA) solar spectra in valid Langley channels as well as regions of strong molecular absorption is also presented. High-altitude Langley plot calibration experiments indicate that this technique is limited ultimately by the current uncertainties in the TOA solar spectra, approximately 2-3%. Example comparisons of measured and modtran-modeled direct solar irradiance show that the model can be parameterized to agree with measurements over the large majority of the wavelength range to the 3% level for the two example cases shown. Side-by-side comparisons with a filter-based solar radiometer are in excellent agreement, with a mean absolute difference of tau = 0.0036 for eight overlapping wavelengths over three experiment days. PMID:18360373

  6. Measurements of solar ultraviolet irradiance with respect to the human body surface

    NASA Astrophysics Data System (ADS)

    Stick, Carsten; Harms, Volker; Pielke, Liane

    1994-07-01

    Solar UV irradiance is measured in Westerland, Germany (54.9 degree(s) N, 8.3 degree(s) E) in the immediate vicinity of the North Sea shoreline. Measurements have been done since July 1993, focussing on the biologically effective UV radiation and the human body geometry. A grid double monochromator radiometer (DM 150, Bentham Instruments Comp., Reading, England) is used to measure the spectral resolution of 1 nm. Weighting the spectral irradiance by the action spectrum for the erythema is more appropriate for determining the biological effectiveness than simply dividing the UV radiation into the UV-A and UV-B wavebands. The erythemal irradiance shows a close relation to the sun angle during the course of a day. The exposure times, calculated from the irradiance and the minimal erythemal doses, suggest that people might underestimate the risk of getting sunburnt before noon. Diffuse radiation scattered from the sky contribute about 70% of the erythemal irradiance at a 45 degree(s) sun angle. A receiver oriented directly to the sun, i.e. 45 degree(s) inclined, receives an additional 30% of the erythemal irradiance measured by a horizontally adjusted cosine response sensor. The relative irradiance of curved surfaces like the skin is determined by UV- B-sensitive paper placed around a cylinder. This device detected UV radiation reflected by the sea, which hardly is measured by horizontally adjusted receivers.

  7. A lunar base for SETI (Search for Extraterrestrial Intelligence)

    NASA Technical Reports Server (NTRS)

    Oliver, Bernard M.

    1988-01-01

    The possibilities of using lanar based radio antennas in search of intelligent extraterrestrial communications is explored. The proposed NASA search will have two search modes: (1) An all sky survey covering the frequency range from 1 to 10 GHz; and (2) A high sensitivity targeted search listening for signals from the approx. 800 solar type stars within 80 light years of the Sun, and covering 1 to 3 GHz.

  8. Can Collimated Extraterrestrial Signals be Intercepted?

    E-print Network

    Forgan, Duncan H

    2014-01-01

    The Optical Search for Extraterrestrial Intelligence (OSETI) attempts to detect collimated, narrowband pulses of electromagnetic radiation. These pulses may either consist of signals intentionally directed at the Earth, or signals between two star systems with a vector that unintentionally intersects the Solar System, allowing Earth to intercept the communication. But should we expect to be able to intercept these unintentional signals? And what constraints can we place upon the frequency of intelligent civilisations if we do? We carry out Monte Carlo Realisation simulations of interstellar communications between civilisations in the Galactic Habitable Zone (GHZ) using collimated beams. We measure the frequency with which beams between two stars are intercepted by a third. The interception rate increases linearly with the fraction of communicating civilisations, and as the cube of the beam opening angle, which is somewhat stronger than theoretical expectations, which we argue is due to the geometry of the GHZ...

  9. The role of extraterrestrial phenomena in extinction.

    PubMed

    Raup, D M

    1988-01-01

    In the several years since the Alvarez report of anomalously high iridium concentrations at the Cretaceous-Tertiary boundary, evidence for the involvement of meteorite impacts in biological extinction has increased dramatically. Much more research will be needed, however, before meteorite impact is established as a general causal factor in extinction. Of ever greater long-term interest is the possibility that other extraterrestrial forces have had important influences on the evolution of life. To recognize the effects of such forces, it will be necessary to coordinate the research of astronomy and paleontology so that testable predictions can be formulated. It is possible that known, systematic changes in the Solar System or Galaxy have had effects on global biology and that these effects have been preserved in the paleontological record. PMID:11542144

  10. The role of extraterrestrial phenomena in extinction

    NASA Technical Reports Server (NTRS)

    Raup, D. M.

    1988-01-01

    In the several years since the Alvarez report of anomalously high iridium concentrations at the Cretaceous-Tertiary boundary, evidence for the involvement of meteorite impacts in biological extinction has increased dramatically. Much more research will be needed, however, before meteorite impact is established as a general causal factor in extinction. Of ever greater long-term interest is the possibility that other extraterrestrial forces have had important influences on the evolution of life. To recognize the effects of such forces, it will be necessary to coordinate the research of astronomy and paleontology so that testable predictions can be formulated. It is possible that known, systematic changes in the Solar System or Galaxy have had effects on global biology and that these effects have been preserved in the paleontological record.

  11. Effects of the El Chichon volcanic cloud on direct and diffuse solar irradiances

    NASA Astrophysics Data System (ADS)

    Baker, C. B.; Kuhn, W. R.; Ryznar, E.

    1984-03-01

    Direct, normal and diffuse solar irradiances and 500 nm aerosol optical depths measured at the University of Michigan departed far from normal on 26 October 1982, when it is concluded that the main stratospheric cloud from the El Chichon volcanic eruption arrived at the 42 deg N latitude of the radiation measurement facility. For clear-sky data analyzed through 19 January 1983, direct solar is about 25 percent less than normal and diffuse solar is about 85 percent greater. For the same aerosol optical depths and solar zenith angles, the ratio of diffuse to direct is about 30 percent greater for about 0.3 cm of precipitable water but nearly the same for 0.9 cm. Aerosol optical depths are nearly three times greater for wind directions that naturally advect the cleanest air. The effect of circumsolar irradiance on the methods used to measure direct normal and diffuse irradiances cause the former to be overestimated and the latter to be underestimated.

  12. Particle–gas reacting flow under concentrated solar irradiation

    Microsoft Academic Search

    G. Maag; W. Lipi?ski; A. Steinfeld

    2009-01-01

    A transient heat transfer model is developed for a reacting flow of CH4 laden with carbon particles directly exposed to concentrated solar radiation and undergoing thermal decomposition into carbon and hydrogen. The unsteady mass and energy conservation equations, coupling convective heat and mass transfer, radiative heat transfer, and chemical kinetics for a two-phase solid–gas flow, are formulated and solved numerically

  13. The Search for Extraterrestrial Intelligence.

    ERIC Educational Resources Information Center

    Jones, Barrie W.

    2003-01-01

    Traces the efforts of Searching for Extraterrestrial Technological Intelligence (SETI) since 1960 when a radio-telescope was used to see if any messages were being sent from the vicinity of two nearby stars. Describes attempts to detect microwave/optical signals and technological modification of the cosmic environment. (Author/KHR)

  14. The search for extraterrestrial intelligence

    Microsoft Academic Search

    Barrie W Jones

    2003-01-01

    The modern era of the search for extraterrestrial technological intelligence (SETI) began in 1960 when a radiotelescope was used to see if any messages were being sent from the vicinity of two nearby stars. Since then there have been many searches, and not just with radiotelescopes. So far ETI has not been found, but the search has only just begun.

  15. 13 Years of SOHO/CELIAS/SEM Calibrated Solar Extreme Ultraviolet Irradiance Data

    NASA Astrophysics Data System (ADS)

    Judge, D.; Didkovsky, L.; Wieman, S.; Gangopadhyay, P.

    2008-12-01

    A verified and updated version of the calibrated SOHO/CELIAS/SEM (absolute) solar extreme ultraviolet (EUV) measurements from the beginning of the mission in 1996 through the present is available at the University of Southern California Space Sciences Center website. To complete this new version, six (1999- 2006) sounding rocket under-flights were analyzed using measurements from both a very stable Rare Gas (Ne) Ionization Cell (RGIC) and a clone of the flight SEM instrument. These sounding rocket under-flights have provided a number of reference points that have been compared with the solar flux data published on our web site (last revised in 2000). These reference points are in good agreement with the solar cycle EUV flux for the 30.4 nm first order (26 nm to 34 nm) SEM channels, indicating a very small (less than 1 percent) averaged difference from the published flux for the six under-flights. Thirteen years of continuous and accurate SEM data will continue to provide important information about short term (solar flares) and long term (solar cycle) changes of EUV solar irradiance, and will be used for advancing solar models, for more accurate Earth atmosphere drag models, ionization proxies, and atmospheric dynamics generally, and will also provide solar EUV measurement overlap with the new SDO Extreme ultraviolet Variability Experiment (EVE), to be launched in 2009.

  16. Optical and Solar Cell Properties of Alpha-ray, Proton, and Gamma-ray Irradiated Cu(In,Ga)Se2 Thin Films and Solar Cells

    Microsoft Academic Search

    Mutsumi Sugiyama; Toshihiro Yasuniwa; Hisayuki Nakanishi; Shigefusa F. Chichibu; Shinichi Kimura

    2010-01-01

    The effects of alpha-ray, proton, and gamma-ray irradiation on the electrical properties of Cu(In,Ga)Se2 (CIGS) solar cells and the photoluminescence spectra of CIGS and CuInSe2 (CIS) thin films were investigated. Particle irradiation using alpha-ray and proton primarily degraded the interfaces of CIGS solar cells, even though the CIS and CIGS thin films did not degraded, in the case of a

  17. Spectral response of InP/Si solar cells irradiated to high proton fluences

    SciTech Connect

    Messenger, S.R. [SFA, Inc., Largo, MD (United States); Xapsos, M.A.; Walters, R.J.; Cotal, H.L. [Naval Research Lab., Washington, DC (United States); Wojtczuk, S.J.; Serreze, H.B. [Spire Corp., Bedford, MA (United States); Summers, G.P. [Naval Research Lab., Washington, DC (United States); [Univ. of Maryland, Baltimore, MD (United States)

    1997-12-31

    InP/Si solar cells have been irradiated with 3 MeV protons to very large fluences where carrier removal, instead of decreases in minority carrier diffusion length, dominates the radiation response. In this regime, radiation-induced expansion of the base depletion width causes I{sub sc} to increase above the pre-irradiation level before falling catastrophically to zero. Current-voltage (IV), capacitance-voltage (CV), quantum efficiency (QE), and electrochemical capacitance-voltage (ECV) profiling measurements are presented.

  18. Recovery of shallow junction GaAs solar cells damaged by electron irradiation

    NASA Technical Reports Server (NTRS)

    Walker, G. H.; Conway, E. J.

    1978-01-01

    Solar cells operated in space are subject to degradation from electron and proton radiation damage. It has been found that for deep junction p-GaAlAs/p-GaAs solar cells some of the electron radiation damage is removed by annealing the cells at 200 C. The reported investigation shows that shallow junction p-GaAlAs/p-GaAs/n-GaAs heteroface solar cells irradiated with 1 MeV electrons show a more complete recovery of short-circuit current than do the deep junction cells. The heteroface p-GaAlAs/p-GaAs/n-GaAs solar cells studied were fabricated using the etch-back epitaxy process.

  19. Recent variability of the solar spectral irradiance and its impact on climate modelling

    NASA Astrophysics Data System (ADS)

    Ermolli, I.; Matthes, K.; Dudok de Wit, T.; Krivova, N. A.; Tourpali, K.; Weber, M.; Unruh, Y. C.; Gray, L.; Langematz, U.; Pilewskie, P.; Rozanov, E.; Schmutz, W.; Shapiro, A.; Solanki, S. K.; Woods, T. N.

    2013-04-01

    The lack of long and reliable time series of solar spectral irradiance (SSI) measurements makes an accurate quantification of solar contributions to recent climate change difficult. Whereas earlier SSI observations and models provided a qualitatively consistent picture of the SSI variability, recent measurements by the SORCE (SOlar Radiation and Climate Experiment) satellite suggest a significantly stronger variability in the ultraviolet (UV) spectral range and changes in the visible and near-infrared (NIR) bands in anti-phase with the solar cycle. A number of recent chemistry-climate model (CCM) simulations have shown that this might have significant implications on the Earth's atmosphere. Motivated by these results, we summarize here our current knowledge of SSI variability and its impact on Earth's climate. We present a detailed overview of existing SSI measurements and provide thorough comparison of models available to date. SSI changes influence the Earth's atmosphere, both directly, through changes in shortwave (SW) heating and therefore, temperature and ozone distributions in the stratosphere, and indirectly, through dynamical feedbacks. We investigate these direct and indirect effects using several state-of-the art CCM simulations forced with measured and modelled SSI changes. A unique asset of this study is the use of a common comprehensive approach for an issue that is usually addressed separately by different communities. We show that the SORCE measurements are difficult to reconcile with earlier observations and with SSI models. Of the five SSI models discussed here, specifically NRLSSI (Naval Research Laboratory Solar Spectral Irradiance), SATIRE-S (Spectral And Total Irradiance REconstructions for the Satellite era), COSI (COde for Solar Irradiance), SRPM (Solar Radiation Physical Modelling), and OAR (Osservatorio Astronomico di Roma), only one shows a behaviour of the UV and visible irradiance qualitatively resembling that of the recent SORCE measurements. However, the integral of the SSI computed with this model over the entire spectral range does not reproduce the measured cyclical changes of the total solar irradiance, which is an essential requisite for realistic evaluations of solar effects on the Earth's climate in CCMs. We show that within the range provided by the recent SSI observations and semi-empirical models discussed here, the NRLSSI model and SORCE observations represent the lower and upper limits in the magnitude of the SSI solar cycle variation. The results of the CCM simulations, forced with the SSI solar cycle variations estimated from the NRLSSI model and from SORCE measurements, show that the direct solar response in the stratosphere is larger for the SORCE than for the NRLSSI data. Correspondingly, larger UV forcing also leads to a larger surface response. Finally, we discuss the reliability of the available data and we propose additional coordinated work, first to build composite SSI data sets out of scattered observations and to refine current SSI models, and second, to run coordinated CCM experiments.

  20. Solar Irradiance Variability: Validation of Satellite-Based Assessment and Prospective Enhancements

    NASA Astrophysics Data System (ADS)

    Nonnenmacher, L.; Coimbra, C.

    2013-12-01

    Based on the technological advances and recent growth rates in deployment, solar energy will contribute significantly in the prospective global energy system. However, the intermittent output characteristics of solar energy systems pose a major challenge for the integration of this renewable power resource into the existing power grid. The intra-day solar variability causing output ramps is primarily caused by clouds and aerosols interacting with solar radiation passing through the atmosphere. Recent advances proposed different methods to assess and quantify irradiance fluctuations at the earth's surface. While remote sensing models based on satellite imagery can provide variability data for a vast domain, the temporal resolution is low and show a dearth of validation. In contrast to that, the spatial resolution of ground based instrumentation is limited whereas temporal resolution, precision and accuracy is high. Our validation of satellite based assessment of solar variability with ground truth measurements shows that the satellite based methods provide an accurate picture of variability with half hourly temporal resolution. However, half hourly variability values disregard a large portion of amplitude and frequency of solar variability on shorter timescales. This contribution seeks to investigate the characteristics of different measures of solar irradiance variability, evaluates the accuracy of common variability assessment techniques and finally proposes methods to estimate solar variability in different microclimates under different atmospheric conditions with improved accuracy. Our work shows a novel hybrid approach based on a combination of satellite and sky imager observations to scale down variability values from a 30 minute resolution to a significantly shorter timescale. Current research investigates the applicability and universality of a scaling-law with multiple inputs to derive temporal variability characteristics.

  1. Photo-recovery of electron-irradiated GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Meulenberg, Andrew

    1995-01-01

    The first long-term (3000 hours) UV testing of unirradiated and 1 MeV electron-irradiated GaAs solar cells, with multilayer-coated coverslides to reduce solar array operating temperature, has produced some unexpected and important results. Two results, independent of the coverslide coatings, are of particular importance in terms of the predictability of GaAs solar-array lifetime in space: ( 1) The GaAs/Ge solar cells used for this series of tests displayed a much higher radiation degradation than that predicted based on JPL Solar Cell Radiation Handbook data. Covered cells degraded more in Isc than did bare cells. Short-term illumination at 60 C did not produce significant recovery (-1%) of the radiation damage. (2) However, electron radiation damage to these GaAs solar celIs anneals at 40 C when exposed to approximately 1 sun AM0 UV light sources for extended periods. The effect appears to be roughly linear with time (-1% of lsc per 1000 UVSH), is large (greater than or equal to 3%), and has not yet saturated (at 3000 hours). This photo-recovery of radiation damage to GaAs solar cells is a new effect and potentially important to the spacecraft community. The figure compares the effects of extended UV on irradiated and unirradiated GaAs solar cells with INTELSAT-6 Si cells. The effect and its generality, the extent of and conditions for photo-recovery, and the implications of such recovery for missions in radiation environments have not yet been determined.

  2. The Development of a New Model of Solar EUV Irradiance Variability

    NASA Technical Reports Server (NTRS)

    Warren, Harry; Wagner, William J. (Technical Monitor)

    2002-01-01

    The goal of this research project is the development of a new model of solar EUV (Extreme Ultraviolet) irradiance variability. The model is based on combining differential emission measure distributions derived from spatially and spectrally resolved observations of active regions, coronal holes, and the quiet Sun with full-disk solar images. An initial version of this model was developed with earlier funding from NASA. The new version of the model developed with this research grant will incorporate observations from SoHO as well as updated compilations of atomic data. These improvements will make the model calculations much more accurate.

  3. Ion-irradiation of complex hydrocarbons: implications for small Solar System bodies

    NASA Astrophysics Data System (ADS)

    Moroz, L.; Baratta, G.; Distefano, E.; Strazzulla, G.; Dotto, E.; Barucci, M.; Arnold, G.

    2003-04-01

    Trans-Neptunian Objects (TNOs) and cometary nuclei show remarkable color variations. In the visual and near-infrared spectral regions their colors may range from red to gray or bluish. This probably indicates that surface alteration processes such as space weathering and impact resurfacing plays an essential role in the color diversity of such bodies. In particular, some previous laboratory ion-irradiation experiments demonstrated a transformation of surface colors of ices from gray to red and further to gray. Additional possibility is a transformation of originally red dark refractory organic surface components into a gray carbonized material as a result of ion irradiation. We simulated such an "ageing" effect by an irradiation of a natural dark red organic samples (asphaltite and kerite). The samples were irradiated by 30-60 keV H+, N+ and Ar++ ions and their reflectance spectra were measured before and after irradiation. The results indicate that initially red spectra of organics progressively flatten with increasing ion fluences. The laboratory spectra have been compared with astronomical spectra of TNOs. We demonstrate that an observed variety of TNO’ spectral slopes can be reproduced by our laboratory spectra corresponding to different ion fluences. If we assume that fresh surfaces of some TNOs are red due to their refractory organic components, then their irradiation by ion populations in the Solar System in combination with collisional evolution exposing these fresh surfaces could have produced a variety of colors.

  4. UV Radiation, Vitamin D and Human Health: An Unfolding Controversy Comparisons of Estimated Economic Burdens due to Insufficient Solar Ultraviolet Irradiance and Vitamin D and Excess Solar UV Irradiance for the United States

    Microsoft Academic Search

    William B. Grant; Cedric F. Garland; Michael F. Holick

    Vitamin D sufficiency is required for optimal health, and solar ultraviolet B (UVB) irradiance is an important source of vitamin D. UVB and\\/or vitamin D have been found in observational studies to be associated with reduced risk for over a dozen forms of cancer, multiple sclerosis, osteoporotic fractures, and several other diseases. On the other hand, excess UV irradiance is

  5. Capacitance and conductance studies on silicon solar cells subjected to 8 MeV electron irradiations

    NASA Astrophysics Data System (ADS)

    Sathyanarayana Bhat, P.; Rao, Asha; Sanjeev, Ganesh; Usha, G.; Priya, G. Krishna; Sankaran, M.; Puthanveettil, Suresh E.

    2015-06-01

    The space grade silicon solar cells were irradiated with 8 MeV electrons with doses ranging from 5-100 k Gy. Capacitance and conductance measurements were carried out in order to investigate the anomalous degradation of the cells in the radiation harsh environments and the results are presented in this paper. Detailed and systematic analysis of the frequency-dependent capacitance and conductance measurements were performed to extract the information about the interface trap states. The small increase in density of interface states was observed from the conductance-frequency measurements. The reduction in carrier concentration upon electron irradiation is due to the trapping of charge carriers by the radiation induced trap centres. The Drive Level Capacitance Profiling (DLCP) technique has been applied to study the properties of defects in silicon solar cells. A small variation in responding state densities with measuring frequency was observed and the defect densities are in the range 1015 -1016 cm-3.

  6. Comparison between satellite and instrumental solar irradiance data at the city of Athens, Greece

    NASA Astrophysics Data System (ADS)

    Markonis, Yannis; Dimoulas, Thanos; Atalioti, Athina; Konstantinou, Charalampos; Kontini, Anna; Pipini, Magdalini-Io; Skarlatou, Eleni; Sarantopoulos, Vasilis; Tzouka, Katerina; Papalexiou, Simon; Koutsoyiannis, Demetris

    2015-04-01

    In this study, we examine and compare the statistical properties of satellite and instrumental solar irradiance data at the capital of Greece, Athens. Our aim is to determine whether satellite data are sufficient for the requirements of solar energy modelling applications. To this end we estimate the corresponding probability density functions, the auto-correlation functions and the parameters of some fitted simple stochastic models. We also investigate the effect of sample size to the variance in the temporal interpolation of daily time series. Finally, as an alternative, we examine if temperature can be used as a better predictor for the daily irradiance non-seasonal component instead of the satellite data. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

  7. Photolysis Kinetics, Mechanisms, and Pathways of Tetrabromobisphenol A in Water under Simulated Solar Light Irradiation.

    PubMed

    Wang, Xiaowen; Hu, Xuefeng; Zhang, Hua; Chang, Fei; Luo, Yongming

    2015-06-01

    The photolysis of tetrabromobisphenol A (TBBPA) in aqueous solution under simulated solar light irradiation was studied under different conditions to find out mechanisms and pathways that control the transformation of TBBPA during photoreaction. Particular attention was paid to the identification of intermediates and elucidation of the photolysis mechanism of TBBPA by UPLC, LC/MS, FT-ICR-MS, NMR, ESR, and stable isotope techniques ((13)C and (18)O). The results showed that the photolysis of TBBPA could occur under simulated solar light irradiation in both aerated and deaerated conditions. A magnetic isotope effect (MIE)-hydrolysis transformation was proposed as the predominant pathway for TBBPA photolysis in both cases. 2,6-Dibromophenol and two isopropylphenol derivatives were identified as photooxidation products of TBBPA by singlet oxygen. Reductive debromination products tribromobisphenol A and dibromobisphenol A were also observed. This is the first report of a photolysis pathway involving the formation of hydroxyl-tribromobisphenol A. PMID:25936366

  8. In Situ Irradiation and Measurement of Triple Junction Solar Cells at Low Intensity, Low Temperature (LILT) Conditions

    Microsoft Academic Search

    R. D. Harris; M. Imaizumi; R. J. Walters; J. R. Lorentzen; S. R. Messenger; J. G. Tischler; T. Ohshima; S. Sato; P. R. Sharps; N. S. Fatemi

    2008-01-01

    The performance of triple junction InGaP\\/(In)GaAs\\/Ge space solar cells was studied following high energy electron irradiation at low temperature. Cell characterization was carried out in situ at the irradiation temperature while using low intensity illumination, and, as such, these conditions reflect those found for deep space, solar powered missions that are far from the sun. Cell characterization consisted of I-V

  9. Effect of Large-Scale Magnetic Fields on Total Solar Irradiance

    Microsoft Academic Search

    A. V. Mordvinov; R. C. Willson

    2003-01-01

    The effect of large-scale magnetic fields on total solar irradiance (TSI) was studied both in time–frequency and in time–longitude aspects. A continuous wavelet analysis revealed that the energy of thermomagnetic disturbances due to sunspots and faculae cascades into the magnetic network and facular macrostructure. A numerical technique of time–longitude analysis was developed to study the fine structure of temporal changes

  10. Solidphase photocatalytic degradation of polyethylene plastic under UV and solar light irradiation

    Microsoft Academic Search

    X u Zhao; Zongwei Li; Yi Chen; Liyi Shi; Yongfa Zhu

    2007-01-01

    This paper investigated solid-phase photocatalytic degradation of polyethylene (PE) plastic with TiO2 in the ambient air under solar and ultraviolet light irradiation. The photodegradation of the composite plastic was compared with that of pure PE through weight loss monitoring, scanning electron microscopic (SEM) analysis, gas chromatography (GC), FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). PE-TiO2 composite plastic can be efficiently

  11. Far ultraviolet and extreme ultraviolet rocket instrumentation for measuring the solar spectral irradiance and terrestrial airglow

    NASA Astrophysics Data System (ADS)

    Woods, Thomas N.; Bailey, Scott M.; Solomon, Stanley C.; Rottman, Gary J.

    1992-06-01

    A sounding-rocket experiment is being developed for the study of EUV spectral irradiance and its effects on the upper atmosphere, using three solar EUV instruments devised by the Laboratory for Atmospheric and Space Physics. These include a 25-cm Rowland circle EUV spectrograph, an array of Si X-UV photodiodes, and an X-UV imager with 20 arcsec resolution of the sun.

  12. Ultraviolet irradiation at elevated temperatures and thermal cycling in vacuum of FEPA covered silicon solar cells

    Microsoft Academic Search

    J. D. Broder; S. J. Marsik

    1978-01-01

    Silicon solar cells covered with FEP-A were irradiated in vacuum with ultraviolet light and then subjected to thermal cycling. These accelerated laboratory conditions are believed to be equivalent to those experienced by FEP-A covered cells on the ATS-6 spacecraft and the results indicate a probable mechanism for the faster degradation of the FEP-A covered cells. Heat-bonded FEP-A covers apparently embrittle

  13. The functional role of tabular structures for large reef fishes: avoiding predators or solar irradiance?

    NASA Astrophysics Data System (ADS)

    Kerry, J. T.; Bellwood, D. R.

    2015-06-01

    Large reef fishes may often be seen sheltering under tabular structures on coral reefs. There are two principle explanations for this behaviour: avoidance of predation or avoidance of solar irradiance. This study sought supporting evidence to distinguish between these two explanations by examining the usage of tabular structures on a shallow mid-shelf reef of the Great Barrier Reef at midday and sunset. If predation avoidance is most important, usage should increase towards sunset; conversely, if avoidance of solar radiation is most important, more fishes should use cover at midday. Underwater video observations revealed that tabular structures were extensively used by large reef fishes at midday, being characterised by numerous species, especially Lutjanidae and Haemulidae. In contrast, at sunset, tabular structures were used by significantly fewer large reef fishes, being characterised mostly by species of unicornfish ( Naso spp.). Resident times of fishes using tabular structures were also significantly longer at midday (28:06 ± 5:55 min) than at sunset (07:47 ± 2:19 min). The results suggest that the primary function of tabular structures for large reef fishes is the avoidance of solar irradiance. This suggestion is supported by the position of fishes when sheltering. The majority of large reef fishes were found to shelter under the lip of tabular structure, facing outwards. This behaviour is thought to allow protection from harmful downwelling UV-B irradiance while allowing the fish to retain photopic vision and survey more of the surrounding area. These findings help to explain the importance of tabular structures for large reef fishes on coral reefs, potentially providing a valuable energetic refuge from solar irradiance.

  14. Analysis of multijunction solar cell degradation in space and irradiation induced recombination centers

    Microsoft Academic Search

    M. Zazoui; M. Mbarki; A. Zin Aldin; J. C. Bourgoin; O. Gilard; G. Strobl

    2003-01-01

    We demonstrate how, using electroluminescence, the parameters characterizing the recombination center induced by irradiation in a solar cell can be measured. Because electroluminescence is able to provide information on an individual cell in a multijunction (MJ) cell device, independently of the others, we apply this technique to measure these parameters in InGaP\\/GaAs\\/Ge MJ cells. We then calculate the variations of

  15. Correlation of electron and proton irradiation-induced damage in InP solar cells

    NASA Technical Reports Server (NTRS)

    Walters, Robert J.; Summers, Geoffrey P.; Messenger, Scott R.; Burke, Edward A.

    1996-01-01

    The measured degradation of epitaxial shallow homojunction n(+)/p InP solar cells under 1 MeV electron irradiation is correlated with that measured under 3 MeV proton irradiation based on 'displacement damage dose'. The measured data is analyzed as a function of displacement damage dose from which an electron to proton dose equivalency ratio is determined which enables the electron and proton degradation data to be described by a single degradation curve. It is discussed how this single curve can be used to predict the cell degradation under irradiation by any particle energy. The degradation curve is used to compare the radiation response of InP and GaAs/Ge cells on an absolute damage energy scale. The comparison shows InP to be inherently more resistant to displacement damage deposition than the GaAs/Ge.

  16. Effect of electron irradiation in vacuum on FEP-A silicon solar cell covers

    NASA Technical Reports Server (NTRS)

    Marsik, S. J.; Broder, J. D.

    1975-01-01

    Fluorinated ethylene-propylene-A (FEP-A) covers on silicon solar cells were irradiated with 1-MeV electrons, in vacuum, to an accumulated fluence equivalent to approximately 28 years in synchronous orbit. The effect of irradiation on the light transmittance of FEP-A was checked by measuring the short-circuit current of the cells after each dose increment. The results indicate no apparent overall loss in transmission due to irradiation of FEP-A. Filter wheel measurements revealed some darkening of the FEP-A at the blue end of the spectrum. Although no delamination from the cell surface was observed while in vacuum, embrittlement of FEP-A occurred at the accumulated dose.

  17. In Situ Irradiation and Measurement of Triple Junction Solar Cells at Low Intensity, Low Temperature (LILT) Conditions

    NASA Technical Reports Server (NTRS)

    Harris, R.D.; Imaizumi, M.; Walters, R.J.; Lorentzen, J.R.; Messenger, S.R.; Tischler, J.G.; Ohshima, T.; Sato, S.; Sharps, P.R.; Fatemi, N.S.

    2008-01-01

    The performance of triple junction InGaP/(In)GaAs/Ge space solar cells was studied following high energy electron irradiation at low temperature. Cell characterization was carried out in situ at the irradiation temperature while using low intensity illumination, and, as such, these conditions reflect those found for deep space, solar powered missions that are far from the sun. Cell characterization consisted of I-V measurements and quantum efficiency measurements. The low temperature irradiations caused substantial degradation that differs in some ways from that seen after room temperature irradiations. The short circuit current degrades more at low temperature while the open circuit voltage degrades more at room temperature. A room temperature anneal after the low temperature irradiation produced a substantial recovery in the degradation. Following irradiation at both temperatures and an extended room temperature anneal, quantum efficiency measurement suggests that the bulk of the remaining damage is in the (In)GaAs sub-cell

  18. Response of the upper atmosphere to variations in the solar soft x-ray irradiance. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Bailey, Scott Martin

    1995-01-01

    Terrestrial far ultraviolet (FUV) airglow emissions have been suggested as a means for remote sensing the structure of the upper atmosphere. The energy which leads to the excitation of FUV airglow emissions is solar irradiance at extreme ultraviolet (EUV) and soft x-ray wavelengths. Solar irradiance at these wavelengths is known to be highly variable; studies of nitric oxide (NO) in the lower thermosphere have suggested a variability of more than an order of magnitude in the solar soft x-ray irradiance. To properly interpret the FUV airflow, the magnitude of the solar energy deposition must be known. Previous analyses have used the electron impact excited Lyman-Birge-Hopfield (LBH) bands of N2 to infer the flux of photoelectrons in the atmosphere and thus to infer the magnitude of the solar irradiance. This dissertation presents the first simultaneous measurements of the FUV airglow, the major atmospheric constituent densities, and the solar EUV and soft x-ray irradiances. The measurements were made on three flights of an identical sounding rocket payload at different levels of solar activity. The linear response in brightness of the LBH bands to variations in solar irradiance is demonstrated. In addition to the N2 LBH bands, atomic oxygen lines at 135.6 and 130.4 nm are also studied. Unlike the LBH bands, these emissions undergo radiative transfer effects in the atmosphere. The OI emission at 135.6 nm is found to be well modeled using a radiative transfer calculation and the known excitation processes. Unfortunately, the assumed processes leading to OI 130.4 nm excitation are found to be insufficient to reproduce the observed variability of this emission. Production of NO in the atmosphere is examined; it is shown that a lower than previously reported variability in the solar soft x-ray irradiance is required to explain the variability of NO.

  19. Higher Efficiency for Quasi-Solid State Dye Sensitized Solar Cells Under Low Light Irradiance

    NASA Astrophysics Data System (ADS)

    Desilva, Ajith; Bandara, T. M. W. J.; Fernado, H. D. N. S.; Fernando, P. S. L.; Dissanayake, M. A. K. L.; Jayasundara, W. J. M. J. S. R.; Furlani, M.; Mellander, B.-E.

    2014-03-01

    Dye-sensitized solar cells (DSSCs), lower cost solar energy conversion devices are alternative green energy source. The liquid based electrolyte DSSCs have higher efficiencies with many practical issues while the quasi-solid-state DSSCs resolve the key problems but efficiencies are relatively low. Polyacrylonitrile (PAN) based gel polymer electrolytes were fabricated as DSSCs by incorporating ethylene carbonate and propylene carbonate plasticizers and tetrapropylammonium iodide salt. A thin layer of electrolyte was sandwiched between the TiO2 anode (sensitized with N719 dye) and the Pt counter electrode. The electrolyte had an ionic conductivity of 2.6 mS/cm at 25 degrees of Celsius. DSSCs incorporating this gel electrolyte revealed Vsc circuit, Jsc, fill factor (FF) and efficiency values of 0.71 V, 11.8 mA, 51 percent and 4.2 percent respectively under 1 sun irradiation. The efficiency of the cell increased with decreasing solar irradiance achieving up to 10 percent efficiency and 80 percent FF at low irradiance values. This work uncovers that quasi-solid state DSSCs can reach efficiencies close to that of liquid electrolytes based cells.

  20. Narrowband filter radiometer for ground-based measurements of global ultraviolet solar irradiance and total ozone

    SciTech Connect

    Petkov, Boyan; Vitale, Vito; Tomasi, Claudio; Bonafe, Ubaldo; Scaglione, Salvatore; Flori, Daniele; Santaguida, Riccardo; Gausa, Michael; Hansen, Georg; Colombo, Tiziano

    2006-06-20

    The ultraviolet narrowband filter radiometer (UV-RAD) designed by the authors to take ground-based measurements of UV solar irradiance, total ozone, and biological dose rate is described, together with the main characteristics of the seven blocked filters mounted on it, all of which have full widths at half maxima that range 0.67 to 0.98 nm. We have analyzed the causes of cosine response and calibration errors carefully to define the corresponding correction terms, paying particular attention to those that are due to the spectral displacements of the filter transmittance peaks from the integer wavelength values. The influence of the ozone profile on the retrieved ozone at large solar zenith angles has also been examined by means of field measurements. The opportunity of carrying out nearly monochromatic irradiance measurements offered by the UV-RAD allowed us to improve the procedure usually followed to reconstruct the solar spectrum at the surface by fitting the computed results, using radiative transfer models with field measurements of irradiance. Two long-term comparison campaigns took place, showing that a mean discrepancy of+0.3% exists between the UV-RAD total ozone values and those given by the Brewer no. 63 spectroradiometer and that mean differences of+0.3% and-0.9% exist between the erythemal dose rates determined with the UV-RAD and those obtained with the Brewer no. 63 and the Brewer no. 104 spectroradiometers, respectively.

  1. Analyzing and simulating the variability of solar irradiance and solar PV powerplants

    E-print Network

    Lave, Matthew S.

    2012-01-01

    a panel’s solar conversion efficiency, power output can besolar panels, since incident radiation is nearly linearly proportional to power output of a PV panel.power production of a PV panel is close to linearly proportional to the amount of solar

  2. Atmospheric aerosols and their impact on surface solar irradiation in Kerkennah Islands (eastern Tunisia)

    NASA Astrophysics Data System (ADS)

    Trabelsi, A.; Saad, M.; Masmoudi, M.; Alfaro, S. C.

    2015-07-01

    In order to assess the impact of the atmospheric particle load on the characteristics of the surface solar irradiation in Central Tunisia, four measurement campaigns have been carried out in periods selected in each season of 2010/2011 on the Kerkennah Islands. During each of these periods, the direct normal and global horizontal components of solar irradiation were measured, which allows determination of the atmospheric turbidity (Linke turbidity factor, TL, and Angström exponent, ?) and of the diffuse fraction (DF) of the irradiation. In parallel, surface aerosols were sampled on filters and subsequently submitted to X-ray fluorescence (XRF) analysis for determination of their elemental composition and apportionment between the mineral dust (MD), sea salt (SS), and non sea salt sulfate (nSS) species. A significant positive correlation is found between the total aerosol concentration and both TL and DF, which indicates that over the measurement period surface aerosol is representative of the columnar particulate content of the atmosphere. A least square iterative routine used to separate the effects of each aerosol type shows that if on average MD, SS, and nSS explain 4, 19 and 12%, respectively, of the TL values, the increase of the MD concentrations during short-duration dust event is responsible for the largest observed values (TL = 6 on 15 April 2010). Similarly, if on average only about 9% of the global horizontal surface irradiation can be ascribed to aerosols, during the aforementioned dust event this share reaches 28%, 19% of which are due to mineral dust.

  3. I-V analysis of high-energy lithium-ion-irradiated Si and GaAs solar cells

    E-print Network

    Meulenberg, A; Ramani,; Radhakrishna, M C; Saif, A K

    2009-01-01

    Space-grade Si and GaAs solar cells were irradiated with 15 and 40 MeV lithium ions. Dark-IV analysis (with and without illumination) reveals differences in the effects of such irradiation on the different cell types

  4. Degradation modeling of InGaP/GaAs/Ge triple-junction solar cells irradiated by protons

    NASA Astrophysics Data System (ADS)

    Maximenko, S. I.; Lumb, M. P.; Messenger, S. R.; Hoheisel, R.; Affouda, C.; Scheiman, D.; Gonzalez, M.; Lorentzen, J.; Jenkins, P. P.; Walters, R. J.

    2014-03-01

    Experimental results on triple-junction solar cells irradiated by 3 MeV proton irradiation to very high damage levels are presented. The minority carrier transport properties were obtained through quantum efficiency and EBIC measurements and an analytical drift-diffusion solver was used in understanding the results for different degradation levels where multiple damage mechanisms are evident.

  5. Modeling of biomass productivity in tubular photobioreactors for microalgal cultures: Effects of dilution rate, tube diameter, and solar irradiance

    Microsoft Academic Search

    F. G. Acién Fernández; F. García Camacho; J. A. Sánchez Pérez; J. M. Fernández Sevilla; E. Molina Grima

    1998-01-01

    A macromodel is developed for estimating the year-long biomass productivity of outdoor cultures of microalga in tubular photobioreactors. The model evalu- ates the solar irradiance on the culture surface as a func- tion of day of the year and the geographic location. In a second step, the geometry of the system is taken into account in estimating the average irradiance

  6. Correlation of electron and proton irradiation-induced damage in InP solar cells

    NASA Technical Reports Server (NTRS)

    Walters, Robert J.; Summers, Geoffrey P.; Messenger, Scott R.; Burke, Edward A.

    1995-01-01

    When determining the best solar cell technology for a particular space flight mission, accurate prediction of solar cell performance in a space radiation environment is essential. The current methodology used to make such predictions requires extensive experimental data measured under both electron and proton irradiation. Due to the rising cost of accelerators and irradiation facilities, such extensive data sets are expensive to obtain. Moreover, with the rapid development of novel cell designs, the necessary data are often not available. Therefore, a method for predicting cell degradation based on limited data is needed. Such a method has been developed at the Naval Research Laboratory based on damage correlation using 'displacement damage dose' which is the product of the non-ionizing energy loss (NIEL) and the particle fluence. Displacement damage dose is a direct analog of the ionization dose used to correlate the effects of ionizing radiations. In this method, the performance of a solar cell in a complex radiation environment can be predicted from data on a single proton energy and two electron energies, or one proton energy, one electron energy, and Co(exp 60) gammas. This method has been used to accurately predict the extensive data set measured by Anspaugh on GaAs/Ge solar cells under a wide range of electron and proton energies. In this paper, the method is applied to InP solar cells using data measured under 1 MeV electron and 3 MeV proton irradiations, and the calculations are shown to agree well with the measured data. In addition to providing accurate damage predictions, this method also provides a basis for quantitative comparisons of the performance of different cell technologies. The performance of the present InP cells is compared to that published for GaAs/Ge cells. The results show InP to be inherently more resistant to displacement energy deposition than GaAs/Ge.

  7. Impedance spectroscopy characterization of proton-irradiated GaInP\\/GaAs\\/Ge triple-junction solar cells

    Microsoft Academic Search

    Xi Zhang; Jianmin Hu; Yiyong Wu; Fang Lu

    2010-01-01

    Impedance spectroscopy (IS) measurements have been carried out to study the degradation of proton-irradiated GaInP\\/GaAs\\/Ge triple-junction (3J) solar cells. Four samples were irradiated with proton energies 40 keV, 100 keV, 130 keV and 4 MeV, respectively; the distribution of irradiation-induced defects was simulated by SRIM software. IS measurement and analysis show that parallel resistance and capacitance of each p-n junction

  8. First performance results of two novel spectroradiometers developed for fast scanning of solar spectra UV irradiance

    NASA Astrophysics Data System (ADS)

    Feister, Uwe; Kaifel, Anton K.; Grewe, Rolf-Dieter; Kaptur, Jasmine; Reutter, Oliver; Wohlfart, Michael; Gericke, Klaus

    2003-11-01

    Two recently developed different types of fast spectroradiometers measuring solar UV irradiance have been compared in a field campaign: i) the UV spectroradiometer on filter model basis (UV-SPRAFIMO) and ii) the modified version of the spectroradiometer SPECTRO 320D by Instrument Systems. The all-weather UV-SPRAFIMO instrument combines a UV filter radiometer with 5 narrow-band (FBHM ~ 2.0 to 2.5 nm) filters centered within +/- 0.01 nm at 303.5, 309.0, 314.5, 327.0 and 387.0 nm, and an advanced neural network-based model. It allows up to 5 measurements per second to be taken that are averaged within time intervals between 5 and 30 s. The neural networks model that is embedded in the PC-based processing software converts the 5 measured irradiances into a full spectrum from 280 to 450 nm at small wavelength steps (>= 0.05 nm). These spectra can be convoluted with user-defined slit function and integrated to broad-band and action-spectra-weighted irradiance values. Users can access the data stored in the internal data logger by a serial RS232 interface or by a modem and display them on a PC-based Graphical User Interface. The spectroradiometer SPECTRO320D consists of a grating double monochromator with a cooled (-20°C) PMT receiver. The modified instrument version run by DWD uses a Schreder type cosine diffuser that directs the solar global irradiance via quartz fiber optics onto the spectroradiometer's entrance slit. The spectroradiometer used at the campaign was installed in a thermostatted (22 +/- 0.02)°C aluminum box. The modified instrument version performs a spectral scan over the whole UV region in two subsequent parts, with a lower speed in the UV-B than in the UV-A to account for the exponential changes of solar irradiance with increasing wavelengths in the UV-B and for the almost linear change in the UV-A region. In the configuration applied in the comparison, i.e. wavelength steps of 0.2 nm within the scan range from 290 nm to 450 nm, the resulting scan time of the SPECTRO 320D was 23 s. The two spectroradiometers, which both have been absolutely calibrated in the DWD lab using FEL 1000 W halogen lamps traceable to the German Physikalisch-Technische Bundesanstalt (PTB), were used in a field campaign at Izana (Tenerife Island) at a height of 2409 m to compare measured spectral and integral values of solar irradiance. Results of that comparison and the instruments" characteristics revealed under those special field conditions will be discussed.

  9. A Compact Solar Spectral Irradiance Monitor for Future Small Satellite and CubeSat Science Opportunities

    NASA Astrophysics Data System (ADS)

    Richard, E. C.; Harber, D.; Snow, M. A.; Harder, J. W.

    2013-12-01

    Accurate and continuous measurements of solar spectral irradiance (SSI) is recognized as being increasingly important to advancing our understanding of the solar influence on Earth's climate. For example, the magnitude of SSI UV variability has significant implications, both directly and indirectly, for the response of the stratosphere and mesosphere, whereas the visible and near infrared SSI variability influences the radiative balance, thermal structure, and dynamics of the lower atmosphere and ocean layers. Recent SSI measurements are providing critical inputs in evaluating and improving present climate models, however they are not yet of sufficient accuracy to stand alone without overlapping records - gaps in the observational record, caused by future mission delays or early failures of existing missions, effectively destroy our ability to link records from different instruments into a continuous, long-term climate quality record. Recent advancements in calibration facilities and techniques make it now possible to improve significantly the accuracy and traceability of future SSI observations and assure quantification of uncertainty as input to increasingly more sophisticated climate models. The goal of the proposed compact SSI monitor is to cover 200-2400 nm with the required SI-traceable accuracy and on-orbit stability to meet the solar input measurement requirements defined in the Earth Science Decadal Survey for establishing benchmark climate records. Building upon our experiences and resources from the Total and Spectral Solar Irradiance Sensor (TSIS) program, the instrument will reduce the cost, size, and characterization and calibration schedule of a solar spectral irradiance monitor with SI-traceable absolute calibration at the 0.2% uncertainty level (k=1) while maintaining 100 ppm relative stability. System level performance characterizations and final end-to-end absolute irradiance calibration will be accomplished with the LASP Spectral Radiometer Facility (SRF), a comprehensive LASP-NIST jointly developed spectral irradiance calibration facility utilizing the SIRCUS tunable laser system tied to an SI-traceable cryogenic radiometer. The instrument utilizes a straightforward low aberration optical design in a compact, folded geometry that overcomes the extremely high tolerance and costly fabrication requirements associated with previous designs while reducing the overall calibration risks. This will potentially mitigate data continuity risks associated with future mission delays by offering an instrument with implementation flexibility for alternative flight opportunities, including ride share and hosted payloads, small satellites and potentially, multi-sensor CubeSat missions, a rapidly emerging technology for low cost orbital science.

  10. Extraterrestrial accretion and glacial cycles

    NASA Technical Reports Server (NTRS)

    Muller, R. A.

    1994-01-01

    We propose that the approx. 100-k.y. cycle seen in terrestrial glaciation is due to changes in meteor flux that come from changes in the Earth's orbit. This model can explain a 70-k.y. 'anomalous' period in climate data and the apparent discrepancy between present extraterrestrial fluxes and those in oceanic sediments. It can be tested by measuring Ir densities in sediments and ice during glacials and interglacials.

  11. The search for extraterrestrial intelligence

    Microsoft Academic Search

    Carl Sagan; Frank Drake

    1975-01-01

    Suggested means of detecting extraterrestrial civilizations are examined. Such suggestions include the construction of a $10 billion, 25-square-mile radio receiver consisting of 1500 component antennas each 100 meters in diameter. Up to the present, 200 stars have been investigated for evidence of intelligent life; the author concedes that at least 200,000 stars would have to be probed to give us

  12. Mat. Res. Soc. Symp. Proc. Vol. 668 @ 2001 Materials Research Society Influence of proton irradiation and development of flexible CdTe solar cells on polyimide

    E-print Network

    Romeo, Alessandro

    irradiation and development of flexible CdTe solar cells on polyimide A. Romeo, D.L. Bätzner, H. Zogg and A-1-4451499, E-mail: tiwari@phys.ethz.ch ABSTRACT CdTe/CdS solar cells of ~10% efficiency, developed under the irradiation; therefore low Isc is measured. Measurements suggest that CdTe solar cells

  13. The angular distributions of ultraviolet spectral irradiance at different solar elevation angles under clear sky conditions

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Hu, LiWen; Wang, Fang; Gao, YanYan; Zheng, Yang; Wang, Yu; Liu, Yang

    2015-05-01

    To investigate the angular distributions of UVA, UVB, and effective UV for erythema and vitamin D (vitD) synthesis, the UV spectral irradiances were measured at ten inclined angles (from 0° to 90°) and seven azimuths (from 0° to 180°) at solar elevation angle (SEA) that ranged from 18.8° to 80° in Shanghai (31.22° N, 121.55° E) under clear sky and the albedo of ground was 0.1. The results demonstrated that in the mean azimuths and with the back to the sun, the UVA, UVB, and erythemally and vitD-weighted irradiances increased with the inclined angles and an increase in SEA. When facing toward the sun at 0°-60° inclined angles, the UVA first increased and then decreased with an increase in SEA; at other inclined angles, the UVA increased with SEA. At 0°-40° inclined angles, the UVB and erythemally and vitD-weighted irradiances first increased and then decreased with an increase in SEA, and their maximums were achieved at SEA 68.7°; at other inclined angles, the above three irradiances increased with an increase in SEA. The maximum UVA, UVB, and erythemally and vitD-weighted irradiances were achieved at an 80° inclined angle at SEA 80° (the highest in our measurements); the cumulative exposure of the half day achieved the maximum at a 60° inclined angle, but not on the horizontal. This study provides support for the assessment of human skin sun exposure.

  14. Originism - Ethics and Extraterrestrial Life

    NASA Astrophysics Data System (ADS)

    Cockell, C. S.

    How should we treat extraterrestrial life, if we ever find it, and does a different origin of life imply a different ethical status? The most likely source of an ethical difference, or `originism,' is the inability to find a coherent definition of `life,' required to assess moral relevance in the first place. Although from a normative point of view biochemical architecture, in itself, does not provide a reason for a difference, there are numerous positions that might encourage us to treat an independent origin of life differently to life that is related to life on Earth. For example, from an instrumental point of view it would provide an opportunity to study another biological data point; it will be a new source of information about the evolution of life, and thus it might be afforded special status. We might consider extraterrestrial life to be special as prudence against the possibility of its mistreatment through an erroneous moral assessment of its worth. Whether extraterrestrial life exists of an independent origin or not, this analysis ultimately can provide a useful device for considering how we should treat entities on Earth whose status as `living' organisms is disputed, specifically viruses.

  15. A new generation of satellite based solar irradiance calculation schemes R. W. Mueller, D. Heinemann, C. Hoyer & R. Kuhlemann

    E-print Network

    Heinemann, Detlev

    A new generation of satellite based solar irradiance calculation schemes R. W. Mueller, D ABSTRACT: A successful integration of solar energy into the existing energy structure highly depends of the enhanced capabilities of the new Meteosat Second Generation (MSG) satellites. The expected quality

  16. A model for light distribution and average solar irradiance inside outdoor tubular photobioreactors for the microalgal mass culture

    Microsoft Academic Search

    F. G. Acién Fernández; F. García Camacho; J. A. Sánchez Pérez; J. M. Fernández Sevilla; E. Molina Grima

    1997-01-01

    A mathematical model to estimate the solar irradiance profile and average light intensity inside a tu- bular photobioreactor under outdoor conditions is pro- posed, requiring only geographic, geometric, and solar position parameters. First, the length of the path into the culture traveled by any direct or disperse ray of light was calculated as the function of three variables: day of

  17. Annealing Enhancement Effect by Light Illumination on Proton Irradiated Cu(In,Ga)Se2 Thin-Film Solar Cells

    Microsoft Academic Search

    Shirou Kawakita; Mitsuru Imaizumi; Masafumi Yamaguchi; Katsumi Kushiya; Takeshi Ohshima; Hisayoshi Itoh; Sumio Matsuda

    2002-01-01

    In this paper, we investigated the high radiation tolerance of copper indium gallium di-selenide (CIGS) thin-film solar cells by conducting in situ measurements of short circuit current and open circuit voltage of CIGS thin-film solar cells during and after proton irradiation under short circuit condition. We found that the annealing rate of proton-induced defects in CIGS thin-film solar cells under

  18. Technical and economical system comparison of photovoltaic and concentrating solar thermal power systems depending on annual global irradiation

    Microsoft Academic Search

    Volker Quaschning

    2004-01-01

    Concentrating solar thermal power and photovoltaics are two major technologies for converting sunlight to electricity. Variations of the annual solar irradiation depending on the site influence their annual efficiency, specific output and electricity generation cost. Detailed technical and economical analyses performed with computer simulations point out differences of solar thermal parabolic trough power plants, non-tracked and two-axis-tracked PV systems. Therefore,

  19. Climate response to changes in atmospheric carbon dioxide and solar irradiance on the time scale of days to weeks

    NASA Astrophysics Data System (ADS)

    Cao, Long; Bala, Govindasamy; Caldeira, Ken

    2012-09-01

    Recent studies show that fast climate response on time scales of less than a month can have important implications for long-term climate change. In this study, we investigate climate response on the time scale of days to weeks to a step-function quadrupling of atmospheric CO2 and contrast this with the response to a 4% increase in solar irradiance. Our simulations show that significant climate effects occur within days of a stepwise increase in both atmospheric CO2 content and solar irradiance. Over ocean, increased atmospheric CO2 warms the lower troposphere more than the surface, increasing atmospheric stability, moistening the boundary layer, and suppressing evaporation and precipitation. In contrast, over ocean, increased solar irradiance warms the lower troposphere to a much lesser extent, causing a much smaller change in evaporation and precipitation. Over land, both increased CO2 and increased solar irradiance cause rapid surface warming that tends to increase both evaporation and precipitation. However, the physiological effect of increased atmospheric CO2 on plant stomata reduces plant transpiration, drying the boundary layer and decreasing precipitation. This effect does not occur with increased solar irradiance. Therefore, differences in climatic effects from CO2 versus solar forcing are manifested within days after the forcing is imposed.

  20. 15. PALEOLIMNOLOGY OF EXTREME COLD TERRESTRIAL AND EXTRATERRESTRIAL ENVIRONMENTS

    E-print Network

    Priscu, John C.

    15. PALEOLIMNOLOGY OF EXTREME COLD TERRESTRIAL AND EXTRATERRESTRIAL ENVIRONMENTS 475 R. Pienitz, M understanding of life's origins on our planet and other extraterrestrial bodies. Liquid water is essential

  1. Identification and characterization of extraterrestrial non-chondritic interplanetary dust

    NASA Technical Reports Server (NTRS)

    Blake, D. F.; Fleming, R. H.

    1991-01-01

    Interplanetary dust particles (IDPs) are among the most pristine and primitive extraterrestrial materials available for direct study. Most of the stratospheric particles selected for study from the JSC Curatorial Collection were chondritic in composition (major element abundances within a factor of two of chondritic meteorites) because this composition virtually ensures that the particle is from an extraterrestrial source. It is likely that some of the most interesting classes of IDP's have not been recognized simply because they are not chondritic or do not fit established criteria for extraterrestrial origin. Indeed, mass spectroscopy data from the Giotto Flyby of comet Halley indicate that a substantial fraction of the dust is in the submicron size range and that a majority of these particles contain C, H, O, and/or N as major elements. The preponderance of CHON particles in the coma of Halley implies that similar particles may exist in the JSC stratospheric dust collection. However, the JSC collection also contains a variety of stratospheric contaminants from terrestrial sources which have these same characteristics. Because established criteria for extraterrestrial origin may not apply to such particles in individual cases, and integrated approach is required in which a variety of analysis techniques are applied to the same particle. Non-chondritic IDP's, like their chondritic counterparts, can be used to elucidate pre- and early solar system processes and conditions. The study of non-chondritic IDP's may additionally yield unique information which bears on the nature of cometary bodies and the processing of carbonaceous and other low atomic number materials. A suite of complementary techniques, including Low Voltage Scanning Electron Microscopy (LVSEM), Energy-Dispersive X-ray Microanalysis (EDX), Secondary Ion Mass Spectrometry (SIMS) isotope-ratio imaging and Analytical Electron Microscopy (AEM), were utilized to accomplish the following two objectives: (1) to develop criteria for the unequivocal identification of extraterrestrial non-chondritic IDP's; and (2) to infer IDP parent body, solar nebula, and pre-solar conditions through the study of phases, textures, and components contained within non-chondritic IDP's. The general approach taken is designed to maximize the total information obtained from each particle. Techniques will be applied in order from least destructive to most destructive.

  2. NIEL Dose Dependence for Solar Cells Irradiated with Electrons and Protons

    E-print Network

    C. Baur; M. Gervasi; P. Nieminen; S. Pensotti; P. G. Rancoita; M. Tacconi

    2014-02-10

    The investigation of solar cells degradation and the prediction of its end-of-life performance is of primary importance in the preparation of a space mission. In the present work, we investigate the reduction of solar-cells' maximum power resulting from irradiations with electrons and protons. Both GaAs single junction and GaInP/GaAs/Ge triple junction solar cells were studied. The results obtained indicate how i) the dominant radiation damaging mechanism is due to atomic displacements, ii) the relative maximum power degradation is almost independent of the type of incoming particle, i.e., iii) to a first approximation, the fitted semi-empirical function expressing the decrease of maximum power depends only on the absorbed NIEL dose, and iv) the actual displacement threshold energy value (Ed=21 eV) accounts for annealing treatments, mostly due to self-annealing induced effects. Thus, for a given type of solar cell, a unique maximum power degradation curve can be determined as a function of the absorbed NIEL dose. The latter expression allows one to predict the performance of those solar cells in space radiation environment.

  3. Niel Dose Dependence for Solar Cells Irradiated with Electrons and Protons

    NASA Astrophysics Data System (ADS)

    Baur, C.; Gervasi, M.; Nieminen, P.; Pensotti, S.; Rancoita, P. G.; Tacconi, M.

    2014-06-01

    The investigation of solar cells degradation and the prediction of its end-of-life performance is of primary importance in the preparation of a space mission. In the present work, we investigate the reduction of solar-cells' maximum power resulting from irradiations with electrons and protons. Both GaAs single junction and GalnP/GaAs/Ge triple junction solar cells were studied. The results obtained indicate how i) the dominant radiation damaging mechanism is due to atomic displacements, ii) the relative maximum power degradation is almost independent of the type of incoming particle, i.e., iii) to a first approximation, the fitted semi-empirical function expressing the decrease of maximum power depends only on the absorbed NIEL dose, and iv) the actual displacement threshold energy value (Ed = 21 eV) accounts for annealing treatments, mostly due to self-annealing induced effects. Thus, for a given type of solar cell, a unique maximum power degradation curve can be determined as a function of the absorbed NIEL dose. The latter expression allows one to predict the performance of those solar cells in space radiation environment.

  4. Modifications of in vitro skin penetration under solar irradiation: evaluation on flow-through diffusion cells.

    PubMed

    Gélis, Christelle; Mavon, Alain; Delverdier, Maxence; Paillous, Nicole; Vicendo, Patricia

    2002-06-01

    The effect of solar irradiation on ex vivo dermatomed hairless rat skin samples maintained in culture on flow-through diffusion cells for at least 24 h was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and by histological observations. Transepidermal water loss (TEWL) measurements and kinetic analysis of the permeation of both tritiated water and 14C caffeine through the skin were performed after full-spectrum solar exposure involving the use of a xenon arc solar simulator. After a UV exposure of less than 420 mJ/cm2, skin integrity and permeation of both water and caffeine did not change significantly. In contrast, after a 420 mJ/cm2 UV exposure, the epidermis appeared more contracted, associated with an increase of 55% of TEWL and 220% of the skin permeation of tritiated water after 6 h. The data suggested a dramatic alteration of the skin barrier integrity. Moreover, the flux of 14C caffeine increased rapidly by 338% of the absorption of water 12 h after irradiation. These results reveal the presence of a threshold UV exposure that would not modify skin penetration. PMID:12081321

  5. Simulation of solar-cycle response in tropical total column ozone using SORCE irradiance

    NASA Astrophysics Data System (ADS)

    Li, K.-F.; Jiang, X.; Liang, M.-C.; Yung, Y. L.

    2012-01-01

    Total column ozone (XO3) abundance in Earth's atmosphere is intimately related to atmospheric chemistry and dynamics. Understanding the solar-cycle modulations of XO3 helps distinguish anthropogenic perturbations from natural variability during the ozone recovery. Here, the solar-cycle signal of tropical XO3 in the Whole Atmosphere Community Climate Model (WACCM) model has been examined using solar spectral irradiance (SSI) estimated from the Naval Research Laboratory (NRL) solar model and that from recent satellite measurements observed by the Solar Radiation and Climate Experiment (SORCE). Four experiments have been conducted with NRL/SORCE SSI and climatological/realistic sea surface temperatures and ice, and all other variability is fixed. In the tropical region 24° S-24° N, using the SORCE SSI as a model input leads to a solar-cycle response of ~5.4 DU/100F10.7, which is ~2 times of that obtained using NRL SSI. The results are slightly different in the presence of El Niño/Southern Oscillation (ENSO) when realistic SST/ice is used, but these differences are within the regression uncertainty of ~0.6 DU/100F10.7. The solar-cycle responses simulated using SORCE SSI agree with those obtained from the merged TOMS/SBUV satellite observations. Using NRL SSI as a model input results in solar-cycle responses that are closer to the ground-based observations, although the accuracy of the latter is limited by the number of stations in the tropics. In all model experiments, the tropical distribution of the solar-cycle response is constant to within ~0.5 DU/100F10.7, which is of the same order as the regression uncertainty. The spatial structures of the regression uncertainty are shown to be correlated with ENSO in the Pacific region. The solar-cycle response obtained using SORCE SSI implies a maximum change in lower stratospheric temperature of ~0.8 K. This may lead to significant impacts on the model solar-cycle responses in atmospheric circulation, precipitation and other hydrological variables that are important for the climate change.

  6. UV testing of solar cells: Effects of antireflective coating, prior irradiation, and UV source

    NASA Technical Reports Server (NTRS)

    Meulenberg, A.

    1993-01-01

    Short-circuit current degradation of electron irradiated double-layer antireflective-coated cells after 3000 hours ultraviolet (UV) exposure exceeds 3 percent; extrapolation of the data to 10(exp 5) hours (11.4 yrs.) gives a degradation that exceeds 10 percent. Significant qualitative and quantitative differences in degradation were observed in cells with double- and single-layer antireflective coatings. The effects of UV-source age were observed and corrections were made to the data. An additional degradation mechanism was identified that occurs only in previously electron-irradiated solar cells since identical unirradiated cells degrade to only 6 +/- 3 percent when extrapolated 10(exp 5) hours of UV illumination.

  7. Silicon solar cell characterization at low temperatures and low illumination as a function of particulate irradiation

    SciTech Connect

    Whitaker, A.F.; Little, S.A.; Peacock, C.L., Jr.

    1983-03-01

    Various configurations of back surface reflector silicon solar cells including small (2 x 2) cm and large (approx. 6 x 6) cm cells with conventional and wraparound contacts were subjected to 1 MeV electron irradiation and characterized under both Earth orbital and deep space conditions of temperatures and illuminations. Current-Voltage (I-V) data were generated from +65 C to -150 C and at incident illuminations from 135.3 mW/sq cm to 5.4 mW/sq cm for these cells. Degradation in cell performance which is manifested only under deep space conditions is emphasized. In addition, the effect of particle irradiation on the high temperature and high intensity and low temperature and low intensity performance of the cells is described. The cells with wraparound contacts were found to have lower efficiencies at Earth orbital conditions than the cells with conventional contacts.

  8. Short circuit current changes in electron irradiated GaAlAs/GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Walker, G. H.; Conway, E. J.

    1978-01-01

    Heteroface p-GaAlAs/p-GaAs/n-GaAs solar cells with junction depths of 0.8, 1.5, and 4 microns were irradiated with 1 MeV electrons. The short-circuit current for the 4 micron junction depth cells is significantly reduced by the electron irradiation. Reduction of the junction depth to 1.5 microns improves the electron radiation resistance of the cells while further reduction of the junction depth to 0.8 microns improves the stability of the cells even more. Primary degradation is in the blue region of the spectrum. Considerable recovery of lost response is obtained by annealing the cells at 200 C. Computer modeling shows that the degradation is caused primarily by a reduction in the minority carrier diffusion length in the p-GaAs.

  9. Model for correcting global solar irradiance measured with rotating shadowband radiometer

    NASA Astrophysics Data System (ADS)

    Xing, Hongyan; Chong, Wei; Sha, Yizhuo; Lv, Wenhua

    2012-04-01

    Global horizontal irradiance (GHI) measured with rotating shadowband radiometer (RSR) is not accurate enough due to thermal sensitivity and nonuniform spectral response of the photovoltaic detector equipped inside. The purpose of this work is to develop a multiple regressive model to correct the errors posed by the temperature and spectrum. The ratio of the reference global horizontal irradiance (RGHI) to the RSR measured GHI is defined as correction factor, based on which, the model is built via device temperature, air mass, and solar zenith angle. Evaluated from various statistical tests such as coefficient of correlation R2, mean bias deviation, root mean square deviation, t-statistic, skewness, and kurtosis, results show that the corrected RSR GHI can be comparable with the high-quality RGHI, which indicates the validity of the model.

  10. The Search for Extraterrestrial Intelligence (SETI)

    Microsoft Academic Search

    Jill Tarter

    2001-01-01

    The search for evidence of extraterrestrial intelligence is placed in the broader astronomical context of the search for extrasolar planets and biomarkers of primitive life elsewhere in the universe. A decision tree of possible search strategies is presented as well as a brief history of the search for extraterrestrial intelligence (SETI) projects since 1960. The characteristics of 14 SETI projects

  11. SAS Honors Seminar 259: Extraterrestrial Life

    E-print Network

    Baker, Andrew J.

    of the assignment? #12; Reading for Wednesday (11/12) Bennett & Shostak 12.3 ­ SETI (Search for Extraterrestrial Intelligence) Alexander & Anderson (2007) and Alexander (2008): SETI@home and a new search strategy #12 SAS Honors Seminar 259: Extraterrestrial Life 11/10/2008 #12; GBT remote observing

  12. SAS Honors Seminar 256: Extraterrestrial Life

    E-print Network

    Baker, Andrew J.

    /15) Bennett & Shostak 12.3 ­ SETI (Search for Extraterrestrial Intelligence) Alexander & Anderson (2007 SAS Honors Seminar 256: Extraterrestrial Life 11/10/2011 #12; Results: Mars vs. Europa vs), Alexander (2008, 2009): SETI@home, a new search strategy, and SERENDIP V Blair (2009) & Pierson (2011

  13. The Search for Extraterrestrial Intelligence, SETI

    Microsoft Academic Search

    Philip Morrison; John Billingham; John Wolfe

    1977-01-01

    Findings are presented of a series of workshops on the existence of extraterrestrial intelligent life and ways in which extraterrestrial intelligence might be detected. The coverage includes the cosmic and cultural evolutions, search strategies, detection of other planetary systems, alternate methods of communication, and radio frequency interference. 17 references. (JFP)

  14. The search for extraterrestrial intelligence: Telecommunications technology

    Microsoft Academic Search

    R. E. Edelson; G. S. Levy

    1980-01-01

    Efforts to discover evidence of intelligent extraterrestrial life have become not only feasible, but respectable. Fledgling observational projects have begun that will use state-of-the-art hardware to develop sophisticated receiving and data processing systems. The rationale behind the Search for Extraterrestrial Intelligence, the manner in which the program is taking shape, and the implications for telecommunications are described. It is concluded

  15. The search for extraterrestrial intelligence: Telecommunications technology

    Microsoft Academic Search

    R. Edelson; G. Levy

    1977-01-01

    Efforts to discover evidence of intelligent extraterrestrial life have become not only feasible, but respectable. Fledgling observational projects have begun that will use stateof-the-art hardware to develop sophisticated receiving and data processing systems. The rationale behind the Search for Extraterrestrial Intelligence (SETI), the manner in which the program is taking shape, and the implications for telecommunications are described. We conclude

  16. The Search for Extraterrestrial Intelligence (SETI)

    Microsoft Academic Search

    F. P. Keenan; M. E. Phillips; S. J. Rose; D. D. Burgess

    1999-01-01

    A brief review is presented of the hypotheses inherent in searches for extraterrestrial intelligence (SETI). Some of the problems associated with such work at radio wavelengths are discussed, such as the optimal choice of a search frequency. It is shown that pulsed laser signals sent from an extraterrestrial civilisation should be observed to be brighter than the parent star, even

  17. Searching for extraterrestrial intelligence - The ultimate exploration

    Microsoft Academic Search

    D. Black; J. Tarter; J. N. Cuzzi; M. Conners; T. A. Clark

    1977-01-01

    A survey highlighting the central issues of the SETI program (Search for Extraterrestrial Intelligence), including its rationale, scope, search problems, and goals is presented. Electromagnetic radiation is suggested as the most likely means via which knowledge of extraterrestrial intelligence will be obtained, and the variables governing these signals are discussed, including: signal frequency and polarization, state, possible coordinates, and signal

  18. Extraterrestrial resources - Implications from terrestrial experience

    Microsoft Academic Search

    Stephen L. Gillett; David L. Kuck

    1992-01-01

    The experience gained by mining valuable deposits on earth is discussed with the purpose of deriving procedures for exploiting lunar and other extraterrestrial resources. Special attention is given to the complexity of the materials to be dealt with and the stages in the development of mining extraterrestrial material using the lessons learned from experience on earth. These lessons are: (1)

  19. Searching for extra-terrestrial civilizations

    NASA Technical Reports Server (NTRS)

    Gindilis, L. M.

    1974-01-01

    The probability of radio interchange with extraterrestrial civilizations is discussed. Difficulties constitute absorption, scattering, and dispersion of signals by the rarified interstellar medium as well as the deciphering of received signals and convergence of semantic concept. A cybernetic approach considers searching for signals that develop from astroengineering activities of extraterrestrial civilizations.

  20. Changes in surface irradiance and meteorological parameters associated with the annular solar Eclipse of 15 January 2010

    NASA Astrophysics Data System (ADS)

    Singh, Ramesh P.; Sharma, Manish; Kaskaoutis, Dimitris G.

    2013-05-01

    An Annular Solar Eclipse (ASE) occurred on 15 January 2010, which was observed in most parts of India. This paper reports the changes observed in solar irradiance and meteorological parameters (temp [T], relative humidity [RH] and dew point) associated with the ASE mainly at three locations (Greater Noida, Kanpur and Hyderabad) in India that are located far away from the eclipse path. A decrease in solar irradiance in the range of 25-59% (maximum in Hyderabad and minimum in Greater Noida) as well as a slight decrease in RH is observed during solar eclipse. The radiosonde and AIRS data show changes in the normal trend of meteorological conditions at different pressure levels indicating strong influence of solar eclipse.

  1. Solar irradiance changes and photobiological effects at earth's surface following astrophysical ionizing radiation events.

    PubMed

    Thomas, Brian C; Neale, Patrick J; Snyder, Brock R

    2015-03-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the Tropospheric Ultraviolet and Visible (TUV) radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance but that relative estimates for increase in exposure to DNA-damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in very limited geographical areas; instead we found a net increase for most of the modeled time-space region. This result has implications for proposed climate changes associated with ionizing radiation events. PMID:25692406

  2. Extraterrestrial consumables production and utilization

    NASA Technical Reports Server (NTRS)

    Sanders, A. P.

    1972-01-01

    Potential oxygen requirements for lunar-surface, lunar-orbit, and planetary missions are presented with emphasis on: (1) emergency survival of the crew, (2) provision of energy consumables for vehicles, and (3) nondependency on an earth supply of oxygen. Although many extraterrestrial resource processes are analytically feasible, this study has considered hydrogen and fluorine processing concepts to obtain oxygen or water (or both). The results are quite encouraging and are extrapolatable to other processes. Preliminary mission planning and sequencing analysis has enabled the programmatic evaluation of using lunar-derived oxygen relative to transportation cost as a function of vehicle delivery and operational capability.

  3. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewski, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the ground in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under-cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 Wm per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  4. Satellite observations of fog over Indo-Gangetic Plains and its influence on solar irradiance

    NASA Astrophysics Data System (ADS)

    Kharol, Shailesh Kumar; Rani Sharma, Anu; Kvs, Badarinath; Roy, P. S.

    Every year, the Northern region of India, especially the Indo-Gangetic Plains (IGPs) region ex-perience severe fog conditions during winter season due to typical meteorological, environmental and prevailing terrain conditions. The IGP region is highly influenced by western disturbances during winter season, which provide ideal conditions for accumulation of pollutants within the boundary layer and often results in fog formation. The formation of fog over IGPs is believed to create numerous health hazards, economic loss and cross-country transportation of aerosols. The fog is also expected to have impact on agriculture, general economy, global and regional climate. It has attracted the global scientific community attention to address the uncertainties pertaining to its formation and physico-chemical properties. The increase in aerosol concen-tration in the lower atmosphere due to biomass-burning events and anthropogenic activities provides more fog formation with water vapor present in atmosphere over IGP region. In the present study, we made an attempt to study the fog conditions that occurred over North In-dian region and long range transport of aerosols from fog region towards southern region during November, 2008 using multi-satellite data sets and ground based observations on aerosol prop-erties and solar irradiance at urban region of Hyderabad, India. False Color Composites (FCC) of IRS-P6 AWiFS, IRS-P4 OCM and Terra/Aqua MODIS images showed an intense fog/aerosol layer over IGP region on 07th -09th November, 2008. The Terra/Aqua MODIS AOD500 and OMI-AI observations showed high values over IGP region due to fog layer and long range trans-port of aerosols from IGP to Southern Indian region. CALIPSO LIDAR observation showed thick layer of fog/aerosols up to above northern/central Indian region with thickness ranging from 1.5 to 3 Kms. NCEP temperature anomaly variation at 700 hPa showed higher values over IGP region attributed upper atmospheric heating due to scattering and absorption of solar irra-diance. Nighttime ground based micro-pulsed lidar observations at Hyderabad showed elevated layer at a height of 5km on 07 November 2008 confirming the long-range transport of aerosols from fog region (IGP) over urban region of Hyderabad, India. Ground-based sun photometer measurements showed considerable increase in AOD500 ( 30%), angstrom parameter ? ( 10%) and decrease in total solar irradiance ( 7%) over Hyderabad, India on 07 November during the fog period compared to normal day corresponding to 04 November 2008. Keywords: Fog, IGP, AOD, LIDAR and solar irradiance

  5. Proton irradiated MBE grown GaInP\\/GaAs single junction and tandem solar cells

    Microsoft Academic Search

    A. B. Kazantsev; J. Lammasniemi; R. Jaakkola; M. Pessa; M. Rajatora; R. K. Jain

    1997-01-01

    Degradation characteristics for MBE grown Ga0.51In0.49P and GaAs single junction and Ga0.51In0.49P\\/GaAs tandem solar cells irradiated with 3 MeV and 10 MeV protons with fluences of 1010- 1013 cm-2 are reported. The cell degradation was characterized with illuminated current-voltage (I-V) and spectral response measurements. Minority carrier diffusion length damage coefficients for the GaAs cells for 3 MeV and 10 MeV

  6. Bulk and Interface Degradation of Amorphous Silicon \\/ Crystalline Silicon Heterojunction Solar Cells Under Proton Irradiation

    Microsoft Academic Search

    Heinz-Christoph Neitzert; Manuela Ferrara; Thomas Mueller; Maximilian Scherff; Wolfgang Fahrner

    2006-01-01

    Two different types of n-type amorphous silicon\\/p-type crystalline silicon heterojunction solar cells-with and without insertion of a thin intrinsic a-Si:H layer-have been irradiated with proton doses between 5.1010 and 5.1012 protons\\/cm2 at 1.7 MeV. They have been investigated as well by classical measurement techniques like spectral response and current-voltage characteristics under illumination as well as by electroluminescence measurements of the

  7. Helioseismology with the ACRIM instrument on the Solar Maximum Mission. [Active Cavity Radiometer Irradiance Monitor

    NASA Technical Reports Server (NTRS)

    Hudson, Hugh S.

    1991-01-01

    The Active Cavity Radiometer Irradiance Monitor (ACRIM) instrument on board SMM pioneered high-precision solar photometry from space, and provided the first detection of solar p-mode oscillations at low degree by this technique. The observations extended from February, 1980, until December, 1989, with a hiatus of low sampling rate in 1981-1984. During summer 1989, the instrument operated in a 'no-shutter' mode with continuous viewing between the orbital gaps. This resulted in a fourfold increase of the duty cycle, and an effective increase in the Nyquist frequency from 3.815 mHz to some tens of mHz. This review discusses the initial results from this campaign along with a general review of the analyses to date of the entire ACRIM data set.

  8. Effects of variable solar irradiance on the reactive power compensation for large solar farm

    Microsoft Academic Search

    Dustin F. Howard; Ronald G. Harley; Jiaqi Liang; Ganesh K. Venayagamoorthy

    2010-01-01

    Dish-Stirling systems are a form of concentrating solar power (CSP) emerging as an efficient and reliable source of renewable energy. Various technical hurdles are involved in the grid interconnection of dish-Stirling systems, particularly with issues related to power factor correction, low voltage ride-through capability, and reactive power planning. While there are no grid-interconnection requirements specific to dish-Stirling technology, the requirements

  9. Characterization of solar cells for space applications. Volume 12: Electrical characteristics of Solarex BSF, 2-ohm-cm, 50-micron solar cells (1978 pilot line) as a function of intensity, temperature, and irradiation

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.; Beckert, D. M.; Downing, R. G.; Miyahira, T. F.; Weiss, R. S.

    1980-01-01

    Electrical characteristics of Solarex back-surface-field, 2-ohm-cm, 50-micron N/P silicon solar cells are presented in graphical and tabular format as a function of solar illumination intensity, temperature, and irradiation.

  10. Direct-normal solar irradiance measurements and turbidity coefficient evaluation in central Spain.

    NASA Astrophysics Data System (ADS)

    Bllbao, Julia; Román, Roberto; Miguel, Argimiro

    2013-04-01

    In order to study the characteristics of solar direct radiation and the atmospheric turbidity in Valladolid, Spain, global, diffuse and direct irradiance data were recorded from May 2010 to December 2011, with a frequency of 10 minute. Measurements used were taken by the Energy and Atmosphere Group (http://www3.uva.es/renova), University of Valladolid, Spain at the Solar Radiometric Station (41,81°N 4.93°W, 840m a.s.l.) located on the Atmosphere Researcher Centre, Villalba de los Alcores, Valladolid, Spain. Sensors were installed in a Sun tracker (Solys 2, Kipp & Zonen) that blocks direct solar radiation using a shadow ball. The system consists of two pyranometers CMP-21 and one pyrheliometer CHP-1 (Kipp & Zonen), respectively. Based on these measurements, the characteristics of direct solar irradiance data were evaluated in order to know the main statistical parameters of the distribution. Angström turbidity coefficient values, beta, were estimated from direct solar irradiance and clear sky conditions. The beta coefficient values were obtained from MODIS satellite instrument, and the aerosol optical depth values, AOD(550nm), were evaluated. The turbidity coefficient beta shows seasonal variation, with higher values in summer (< 0.15) and lower in winter (< 0.05). It could be due to high temperatures in summer and less rainy days which would induce more atmospheric turbidity, increasing vertical convection and particles enhancement. The scattered graph of aerosol optical depth from satellite and the obtained from Angström expression has been plotted. The slope presents a value around the unity, 0.96, and the correlation coefficient shows a value of 0.6 . It was observed that turbidity coefficients increased in April 2011, and in order to now the origin the change, air masses trajectories, deduced from HYSPLIT model (http://ready.arl.noaa.gov/HYSPLIT.php) were studied. From the results it has been obtained that a situation of low pressures in the Atlantic Portuguese coast and high pressure in the North of Spain induced the movement of dust from Sahara desert into the Iberian Peninsula.

  11. Solar wind and cosmic ray irradiation of grains and ices - application to erosion and synthesis of organic compounds in the solar system

    NASA Technical Reports Server (NTRS)

    Rocard, F.; Benit, J.; Meunier, J. P.; Bibring, R.; Vassent, B.

    1984-01-01

    Solar wind and cosmic and cosmic ray irradiation of grains induces physical and chemical effects including their erosion and the synthesis of molecular compounds within the implanted layers. The experiments performed with H2O ice implanted by keV ions are presented. The ion implantation is intended to simulate the irradiation of comets, ring grains, and satellites of outer planets, either by the primitive solar particles or by contemporary solar wind (SW) or solar cosmic rays (SCR) fluxes. The detection of molecules was obtained through in-situ infrared spectroscopy. A model is proposed for the formation of organic matter within icy solar system bodies which is in agreement with experimental results of erosion rates. The organic molecules, frozen-in within the icy mantles of the grains present in the protosolar nebula, would originate from their primitive irradiation. Such an irradiation would have taken place during an early stage of the proto-sun, when both the SW and SCR particles were more intense by orders of magnitude.

  12. Prediction and measurement of direct-normal solar irradiance: A closure experiment

    NASA Technical Reports Server (NTRS)

    Halthore, R. N.; Schwartz, S. E.; Michalsky, J. J.; Anderson, G. P.; Ferrare, R. A.; Ten Brink, H. M.

    1997-01-01

    Direct-Normal Solar Irradiance (DNSI), the total energy in the solar spectrum incident on a plane perpendicular to the Sun's direction on a unit area at the earth's surface in unit time, depends only on the atmospheric extinction of sunlight without regard to the details of extinction-whether absorption or scattering. Here the authors describe a set of closure experiments performed in north-central Oklahoma, wherein measured atmospheric composition is input to a radiative transfer model, MODTRAN-3, to predict DNSI, which is then compared to measured values. Thirty six independent comparisons are presented; the agreement between predicted and measured values falls within the combined uncertainties in the prediction (2%) and measurement (0.2%) albeit with a slight bias ((approximately) 1% overprediction) that is independent of the solar zenith angle. Thus these results establish the adequacy of current knowledge of the solar spectrum and atmospheric extinction as embodied in MODTRAN-3 for use in climate models. An important consequence is the overwhelming likelihood that the atmospheric clear-sky absorption is accurately described to within comparable uncertainties.

  13. NIEL Dose Dependence for Solar Cells Irradiated with Electrons and Protons

    E-print Network

    Baur, C; Nieminen, P; Pensotti, S; Rancoita, P G; Tacconi, M

    2013-01-01

    The investigation of solar cells degradation and the prediction of its end-of-life performance is of primary importance in the preparation of a space mission. In the present work, we investigate the reduction of solar-cells' maximum power resulting from irradiations with electrons and protons. Both GaAs single junction and GaInP/GaAs/Ge triple junction solar cells were studied. The results obtained indicate how i) the dominant radiation damaging mechanism is due to atomic displacements, ii) the relative maximum power degradation is almost independent of the type of incoming particle, i.e., iii) to a first approximation, the fitted semi-empirical function expressing the decrease of maximum power depends only on the absorbed NIEL dose, and iv) the actual displacement threshold energy value (Ed=21 eV) accounts for annealing treatments, mostly due to self-annealing induced effects. Thus, for a given type of solar cell, a unique maximum power degradation curve can be determined as a function of the absorbed NIEL d...

  14. Prediction and measurement of direct-normal solar irradiance: A closure experiment

    SciTech Connect

    Halthore, R.N.; Schwartz, S.E. [Brookhaven National Lab., Upton, NY (United States); Michalsky, J.J. [State Univ. of New York, Albany, NY (United States); Anderson, G.P. [Hanscomb AFB (United States); Ferrare, R.A. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Ten Brink, H.M. [Energy Research Inst. (Netherlands)

    1997-03-01

    Direct-normal solar irradiance (DNSI), the total energy in the solar spectrum incident on a plane perpendicular to the Sun`s direction on a unit area at the earth`s surface in unit time, depends only on the atmospheric extinction of sunlight without regard to the details of extinction--whether absorption or scattering. Here the authors describe a set of closure experiments performed in north-central Oklahoma, wherein measured atmospheric composition is input to a radiative transfer model, MODTRAN-3, to predict DNSI, which is then compared to measured values. Thirty six independent comparisons are presented; the agreement between predicted and measured values falls within the combined uncertainties in the prediction (2%) and measurement (0.2%) albeit with a slight bias ({approximately} 1% overprediction) that is independent of the solar zenith angle. Thus these results establish the adequacy of current knowledge of the solar spectrum and atmospheric extinction as embodied in MODTRAN-3 for use in climate models. An important consequence is the overwhelming likelihood that the atmospheric clear-sky absorption is accurately described to within comparable uncertainties.

  15. Solar irradiance and aerosol optical properties during the CARES field campaign

    NASA Astrophysics Data System (ADS)

    Barnard, J.; Kassianov, E.

    2010-12-01

    Measurements of both broadband and spectral solar irradiances were made during the Carbonaceous Aerosols and Radiative Effects Study (CARES) field campaign at the T0 and T1 sites. The broadband irradiances were measured using a typical Eppley Precision Spectral Pyranometer (PSP), while the spectral irradiances were measured by a Multi-Filter Rotating Shadowband Radiometer (MFRSR) at six wavelengths (415, 500, 615, 673, 870, and 940 nm). The aerosol optical depth (AOD), single scattering albedo (SSA), and asymmetry parameter (AP), can be inferred from the MFRSR measurements for the first five of these wavelengths. Analyses of these data show three distinct aerosol regimes. The first period, at the beginning of the field campaign, was extremely clean, with AOD values at 500nm as low as 0.03 (with uncertainty of 0.02). Such clear air rivals that at other pristine locations, such as Barrow, Alaska, in late summer. Next, a brief episode of biomass burning took place on June 16, as indicated by increased AOD. Finally, towards the end of the campaign, progressively deteriorating air quality was observed with a concomitant increase in AOD, with values 0.1 (500 nm) and larger. However, at no time during the campaign did the air quality deteriorate to the extent that might be observed in less clean locations such as Mexico City, or more humid places were significant hydroscopic growth occurs. The broadband irradiances also reflect clean conditions, with midday total, hemispherical irradiances often exceeding 1000 W/m^2. We also show some initial results of columnar SSA and AP values derived during the three aerosol regimes. MFRSR data taken near the T1 site during the summer of 2009 also indicate generally clear skies, except during episodes of biomass burning when the AOD approaches 1.0 at 500 nm. Such dirty air was never observed during the CARES campaign.

  16. A new empirical approach in the Search for Extraterrestrial Intelligence: Astrobiological nonlocality at the cosmological level

    Microsoft Academic Search

    Fred H. Thaheld

    2006-01-01

    Over a period of several decades a concerted effort has been made to determine whether intelligent life exists outside of our solar system, known as the Search for Extraterrestrial Intelligence or SETI. This has been based primarily upon attempting to intercept possible radio transmissions at different frequencies with arrays of radio telescopes. In addition, astrophysical observations have also been undertaken

  17. The impact of gravitational microlensing on searches for extraterrestrial intelligence at optical wavelengths

    Microsoft Academic Search

    T. Joseph W. Lazio

    2004-01-01

    The search for extraterrestrial intelligence (SETI) at optical wavelengths counts photons from target stars. The rationale is that the number of photons received from a solar-type star in a nanosecond is typically much less than unity and that an excess number of photons may be indicative of a laser pulse from a technological civilization. Extreme magnification gravitational microlensing is a

  18. SETV: opportunity for European initiative in the search for extraterrestrial intelligence

    Microsoft Academic Search

    Eamonn Ansbro; Catherine Overhauser

    2001-01-01

    Over the last 50 years, experienced and serious scientists have put forward numerous theories suggesting the possibility that probes sent from extraterrestrial civilizations could theoretically be located within the solar system or near the Earth. A significant body of published theoretical research in this area already exists in books and peer-reviewed journals. What has been missing, however, is the funding

  19. Application of CL\\/EBIC-SEM techniques for characterization of irradiation induced defects in triple junction solar cells

    Microsoft Academic Search

    S. I. Maximenko; S. R. Messenger; C. Cress; M. Gonzalez; J. A. Freitas; R. J. Walters

    2010-01-01

    We report the results of the characterization of irradiated InGaP2\\/GaAs\\/Ge multijunction (MJ) solar cells using the cathodoluminescence (CL) imaging\\/spectroscopy and electron beam induced current (EBIC) modes of scanning electron microscopy (SEM). These techniques were applied to verify the influence of irradiation damage on the optoelectronic properties of each subcell triple junction structure and correlate illuminated (AM0, 1 sun, 25°C) current-voltage

  20. Fast measurements of solar spectral UV irradiance—first performance results of two novel spectroradiometers

    NASA Astrophysics Data System (ADS)

    Feister, Uwe; Kaifel, Anton K.; Grewe, Rolf-Dieter; Kaptur, Jasmine; Reutter, Oliver; Wohlfart, Michael; Gericke, Klaus

    2005-04-01

    Short spectral scan times of preferably less than 1 min in the UV region are an important prerequisite for modern spectroradiometers to reflect short-term solar irradiance radiation variations that can occur as a result of fast changes in cloud cover and/or cloud optical depth. Two different types of fast measuring spectroradiometers for solar UV irradiance are compared in a first field campaign: (1) the UV spectroradiometer on filter model basis (UV-SPRAFIMO) and (2) the modified version of the spectroradiometer SPECTRO 320D by Instrument Systems. The UV-SPRAFIMO instrument combines a filter radiometer with five narrowband (FWHM?2.0 to 2.7 nm) filters centered at fixed wavelengths in the UV-B and UV-A regions with an advanced neural network-based model. Up to 5 measurements/s can be taken concurrently in the five wavelength channels. After averaging the measurements over preselectable time intervals, the measured irradiances are converted by the neural network model into a full spectrum from 280 to 450 nm at arbitrary wavelength steps (>=0.05 nm). The SPECTRO 320D spectroradiometer consists of a grating double monochromator with a cooled photomultiplier tube (PMT) receiver. The instrument version run by Deutscher Wetterdienst (DWD) is thermostatted and equipped with a Schreder type cosine diffuser as the entrance optics. A spectral scan from 290 to 450 nm with a selected 0.2-nm wavelength step takes less than 30 s. The two spectroradiometers are used in a field campaign at Izana (Tenerife Island) at a height of 2440 m above sea level (ASL) to compare measured spectral and integral values of solar irradiance. Results of that comparison and the instruments' characteristics are discussed. This first field comparison shows that due to the fast measurements regime, cloud effects on the measured spectra can be appreciably reduced. The campaign shows an acceptable agreement between the spectra measured by both instruments. It also reveals some issues for further improvements of the instrument design.

  1. Quarantine provisions for unmanned extra-terrestrial missions

    NASA Technical Reports Server (NTRS)

    1976-01-01

    This document sets forth requirements applicable to unmanned planetary flight programs which are necessary to enable the Associate Administrator for Space Science to fulfill those responsibilities pertaining to planetary quarantine as stated in NPD 8020.7 and NPD 8020.10A. This document is specifically directed to the control of terrestrial microbial contamination associated with unmanned space vehicles intended to encounter, orbit, flyby, or otherwise be in the vicinity of extra-terrestrial solar system bodies. The requirements of this document apply to all unmanned planetary flight programs. This includes solar system exploratory missions to the major planets as well as missions to planet satellites, or to other solar system objects that may be of scientific interest. This document is not applicable to terrestrial (including lunar) missions and manned missions. NASA officials having cognizance of applicable flight programs will invoke these requirements in such directives or contractual instruments as may be necessary to assure their implementation.

  2. Midwestern streamflow, precipitation, and atmospheric vorticity influenced by Pacific sea-surface temperatures and total solar-irradiance variations

    USGS Publications Warehouse

    Perry, C.A.

    2006-01-01

    A solar effect on streamflow in the Midwestern United States is described and supported in a six-step physical connection between total solar irradiance (TSI), tropical sea-surface temperatures (SSTs), extratropical SSTs, jet-stream vorticity, surface-layer vorticity, precipitation, and streamflow. Variations in the correlations among the individual steps indicate that the solar/hydroclimatic mechanism is complex and has a time element (lag) that may not be constant. Correct phasing, supported by consistent spectral peaks between 0.092 and 0.096 cycles per year in all data sets within the mechanism is strong evidence for its existence. A significant correlation exists between total solar irradiance and the 3-year moving average of annual streamflow for Iowa (R = 0.67) and for the Mississippi River at St Louis, Missouri (R = 0.60), during the period 1950-2000. Published in 2005 by John Wiley & Sons, Ltd.

  3. A 24-h forecast of solar irradiance using artificial neural network: Application for performance prediction of a grid-connected PV plant at Trieste, Italy

    Microsoft Academic Search

    Adel Mellit; Alessandro Massi Pavan

    2010-01-01

    Forecasting of solar irradiance is in general significant for planning the operations of power plants which convert renewable energies into electricity. In particular, the possibility to predict the solar irradiance (up to 24 h or even more) can became - with reference to the Grid Connected Photovoltaic Plants (GCPV) - fundamental in making power dispatching plans and - with reference

  4. A 24-h forecast of solar irradiance using artificial neural network: Application for performance prediction of a grid-connected PV plant at Trieste, Italy

    Microsoft Academic Search

    Adel Mellit; Alessandro Massi Pavan

    2010-01-01

    Forecasting of solar irradiance is in general significant for planning the operations of power plants which convert renewable energies into electricity. In particular, the possibility to predict the solar irradiance (up to 24h or even more) can became – with reference to the Grid Connected Photovoltaic Plants (GCPV) – fundamental in making power dispatching plans and – with reference to

  5. Extraterrestrials

    NSDL National Science Digital Library

    This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on our attempts to reach intelligent life by sending messages into space. Students look at a visual of the message that has been sent from the Arecibo radio dish in Puerto Rico, and discuss what it means and the possibility of getting a reply. It includes objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

  6. Enhanced efficiency of the dye-sensitized solar cells by excimer laser irradiated carbon nanotube network counter electrode

    NASA Astrophysics Data System (ADS)

    Chien, Yun-San; Yang, Po-Yu; Lee, I.-Che; Chu, Chih-Chieh; Chou, Chia-Hsin; Cheng, Huang-Chung; Fu, Wei-En

    2014-02-01

    The carbon nanotube network decorated with Pt nanoparticles (PtCNT) irradiated by excimer laser as counter electrode (CE) of dye-sensitized solar cells (DSSCs) has been systematically demonstrated. The conversion efficiency would be improved from 7.12% to 9.28% with respect to conventional Pt-film one. It was attributed to the enhanced catalytic surface from Pt nanoparticles and the improved conductivity due to the adjoining phenomenon of PtCNTs irradiated by laser. Moreover, the laser annealing could also promote the interface contact between CE and conductive glass. Therefore, such a simple laser-irradiated PtCNT network is promising for the future flexible DSSCs applications.

  7. Annealing Enhancement Effect by Light Illumination on Proton Irradiated Cu(In,Ga)Se2 Thin-Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Kawakita, Shirou; Imaizumi, Mitsuru; Yamaguchi, Masafumi; Kushiya, Katsumi; Ohshima, Takeshi; Itoh, Hisayoshi; Matsuda, Sumio

    2002-07-01

    In this paper, we investigated the high radiation tolerance of copper indium gallium di-selenide (CIGS) thin-film solar cells by conducting in situ measurements of short circuit current and open circuit voltage of CIGS thin-film solar cells during and after proton irradiation under short circuit condition. We found that the annealing rate of proton-induced defects in CIGS thin-film solar cells under light illumination with an AM0 solar simulator is higher than that under dark conditions. The activation energy of proton-induced defects in the CIGS thin-film solar cells with (without) light illumination is 0.80 eV (0.92 eV), which implies on enhanced defect annealing rate in CIGS thin-film solar cells due to minority-carrier injection.

  8. The sensitivity of calculated short-circuit currents to selected irradiance distributions and solar cell spectral responses

    NASA Astrophysics Data System (ADS)

    Hartman, J. S.; Lind, M. A.; Chaudiere, D. A.

    1982-07-01

    Calculations of normalized differences in solar cell short-circuit currents are reported for a variety of solar cell materials and illumination sources. All results were referenced to the cell response under a standard air mass 1.5 irradiance distribution. Each solar cell and source combination was evaluated for two candidate source normalization procedures. The first is a photon flux normalization technique in the 300-1100 nm wavelength region and the second is an energy flux normalization procedure over the 300-2500 nm wavelength band. Practical laboratory approximations of these techniques can be implemented with a good silicon detector and a black detector respectively. Results are reported for 15 different solar cells and six illumination sources (two alternative solar spectra and four artificial sources). The results clearly indicate the importance of carefully selecting the illumination source and the source normalization procedure for the specific solar cell to be evaluated.

  9. Correlation between Displacement Damage Dose and Proton Irradiation Effects on GaInP\\/GaAs\\/Ge Space Solar Cells

    Microsoft Academic Search

    Yun-Hong Liu; Rong Wang; Xin-Yu Cui; Yong-Xia Wang

    2009-01-01

    The irradiation effects of 0.28-2.80 MeV protons on GaInP\\/GaAs\\/Ge solar cells have been analysed, and then correlated with the displacement damage dose. The results of I-V and spectral response measurements, combined with the SRIM-derived vacancies produced rates, show that the degradation of the solar cells is largely determined by the displacement damage of the GaAs sub-cell. Thus the SRIM-derived NIEL

  10. Investigation about the dependence of spectral diffuse-to-direct-beam irradiance ratio on atmospheric turbidity and solar zenith angle

    Microsoft Academic Search

    D. G. Kaskaoutis; H. D. Kambezidis; Z. Tóth

    2007-01-01

    Summary  The modifications of the solar spectral diffuse and direct-beam irradiances as well as the diffuse-to-direct-beam ratio, Ed?\\/Eb?, as a function of the aerosol optical depth, AOD, and solar zenith angle, SZA, is investigated. The Ed?\\/Eb? ratios decrease rapidly with wavelength and exponential curves in the form Ed?\\/Eb? = a??b can be fitted with a great accuracy. These curves are strongly

  11. The response of middle atmospheric ozone to solar UV irradiance variations with a period of 27 days

    NASA Technical Reports Server (NTRS)

    Chen, LI; Brasseur, Guy; London, Julius

    1994-01-01

    A one-dimensional photochemical-dynamical-radiative time-dependent model was used to study the response of middle atmospheric temperature and ozone to solar UV irradiance variations with the period of 27 days. The model solar UV O(x), HO(x), NO(x), and CIO(x)families and modeled solar UV variations. The amplitude of the primary temperature response to the solar UV variation is plus 0.4 K at 85-90 km with a phase lag of about 6 days. A secondary maximum response of plus 0.3 K at 45-50 km appears with a phase lag of 1 day. There is a maximum positive ozone response to the 27-day solar UV oscillation of 2.5 percent at 80-90 km with a phase lag of about 10 days after the solar irradiance maximum. At 70 km the ozone response is about 1.2 percent and is out of phase with the solar variation. In the upper stratosphere (40-50 km) the relative ozone variation is small, about 0.2 percent to 0.3 percent, and there is a negative phase of about 4 days between the ozone and solar oscillations. These oscillations are in phase in the middle stratosphere (35-40 km) where there is again a maximum relative response of about 0.6 percent. The reasons for these ozone amplitude and phase variations are discussed.

  12. Diffusion lengths in irradiated N/P InP-on-Si solar cells

    NASA Technical Reports Server (NTRS)

    Wojtczuk, Steven; Colerico, Claudia; Summers, Geoffrey P.; Walters, Robert J.; Burke, Edward A.

    1995-01-01

    Indium phosphide (InP) solar cells are being made on silicon (Si) wafers (InP/Si) to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers compared to InP or germanium (Ge) wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. InP/Si cells have higher absolute efficiency after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells. In this work, base electron diffusion lengths in the N/P cell are extracted from measured AM0 short-circuit photocurrent at various irradiation levels out to an equivalent 1 MeV fluence of 1017 1 MeV electrons/sq cm for a 1 sq cm 12% BOL InP/Si cell. These values are then checked for consistency by comparing measured Voc data with a theoretical Voc model that includes a dark current term that depends on the extracted diffusion lengths.

  13. Evaporation and solar irradiance as regulators of sea surface temperature in annual and interannual changes

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Zhang, Anzhen; Bishop, James K. B.

    1994-01-01

    Seven years of net surface solar irradiance (S) derived from cloud information provided by the International Satellite Cloud Climatology Project (ISCCP) and 4 years of surface latent heat flux (E) derived from the observations of the special sensor microwave imager (SSM/I) were used to examine the relation between surface heat fluxes and sea surface temperature (T(sub s)) in their global geographical distribution, seasonal cycle, and interannual variation. The relations of seasonal changes imply that evaporation cooling is significant over most of the ocean and that solar heating is the main drive for the change of T(sub s) away from the equatorial wave guide where ocean dynamics may be more important. However, T(sub s) is not the most direct and significant factor in the seasonal changes of S and E over most of the ocean; the solar incident angle may be more important to S, and wind speed and air humidity are found to correlate better with E. Significant local correlations between anomalies of T(sub s) and S and between anomalies of T(sub s) and E are found in the central equatorial Pacific; both types of correlation are negative. The influence of ocean dynamics in changing T(sub s) in the tropical ocean cannot be ignored.

  14. Detection of solar wind-produced water in irradiated rims on silicate minerals.

    PubMed

    Bradley, John P; Ishii, Hope A; Gillis-Davis, Jeffrey J; Ciston, James; Nielsen, Michael H; Bechtel, Hans A; Martin, Michael C

    2014-02-01

    The solar wind (SW), composed of predominantly ?1-keV H(+) ions, produces amorphous rims up to ?150 nm thick on the surfaces of minerals exposed in space. Silicates with amorphous rims are observed on interplanetary dust particles and on lunar and asteroid soil regolith grains. Implanted H(+) may react with oxygen in the minerals to form trace amounts of hydroxyl (-OH) and/or water (H2O). Previous studies have detected hydroxyl in lunar soils, but its chemical state, physical location in the soils, and source(s) are debated. If -OH or H2O is generated in rims on silicate grains, there are important implications for the origins of water in the solar system and other astrophysical environments. By exploiting the high spatial resolution of transmission electron microscopy and valence electron energy-loss spectroscopy, we detect water sealed in vesicles within amorphous rims produced by SW irradiation of silicate mineral grains on the exterior surfaces of interplanetary dust particles. Our findings establish that water is a byproduct of SW space weathering. We conclude, on the basis of the pervasiveness of the SW and silicate materials, that the production of radiolytic SW water on airless bodies is a ubiquitous process throughout the solar system. PMID:24449869

  15. Model Calculations of Solar Spectral Irradiance in the 3.7 Micron Band for Earth Remote Sensing Applications

    NASA Technical Reports Server (NTRS)

    Platnick, Steven; Fontenla, Juan M.

    2006-01-01

    Since the launch of the first Advanced Very High Resolution Radiometer (AVHRR) instrument aboard TIROS-N, measurements in the 3.7 micron atmospheric window have been exploited for use in cloud detection and screening, cloud thermodynamic phase and surface snow/ice discrimination, and quantitative cloud particle size retrievals. The utility of the band has led to the incorporation of similar channels on a number of existing satellite imagers and future operational imagers. Daytime observations in the band include both reflected solar and thermal emission energy. Since 3.7 micron channels are calibrated to a radiance scale (via onboard blackbodies), knowledge of the top-of-atmosphere solar irradiance in the spectral region is required to infer reflectance. Despite the ubiquity of 3.7 micron channels, absolute solar spectral irradiance data comes from either a single measurement campaign (Thekaekara et al. 1969) or synthetic spectra. In this study, we compare historical 3.7 micron band spectral irradiance data sets with the recent semi-empirical solar model of the quiet-Sun by Fontenla et al. (2006). The model has expected uncertainties of about 2 % in the 3.7 pm spectral region. We find that channel-averaged spectral irradiances using the observations reported by Thekaekara et al. are 3.2-4.1% greater than those derived from the Fontenla et al. model for MODIS and AVHRR instrument bandpasses; the Kurucz spectrum (1995) as included in the MODTRAN4 distribution, gives channel-averaged irradiances 1.2-1.5 % smaller than the Fontenla model. For the MODIS instrument, these solar irradiance uncertainties result in cloud microphysical retrievals uncertainties comparable with other fundamental reflectance error sources.

  16. SOLSPEC investigation on board the International Space Station: The Absolute Solar Spectral Irradiance in the Infrared Domain

    NASA Astrophysics Data System (ADS)

    Thuillier, Gérard; Harder, Jerry; Shapiro, Alexander; Woods, Thomas; Perrin, Jean-Marie; Snow, Marty; Sukhodolov, Timofei; Schmutz, Werner

    2015-04-01

    Onboard the SOLAR payload of the International Space Station (ISS), the SOLSPEC spectrometer measures the solar spectral irradiance (SSI) from 16 to 2900 nm. This instrument uses lamps to monitor its behavior in orbit. In particular, it employs two tungsten ribbon lamps in the IR domain (1000-2900 nm). Initially, the infrared absolute irradiance scale was determined from the preflight laboratory calibration coefficients and the in-flight measurements gathered at first light in April 2008. Subsequent publications suggest a systematic discrepancy between SOLAR-ISS measurements and the ATLAS 3 spectrum obtained from SOLSPEC observations onboard the shuttle-ATLAS missions with the discrepancy reaching 10 % at 1800 nm. We show that such a discrepancy has strong implications for the Total Solar Irradiance (TSI) and the brightness temperature of the lower solar photosphere. Furthermore, comparisons with independent spectra either obtained on ground and in space will be also shown and commented. The origin of the ATLAS 3 to SOLSPEC differences have been extensively analyzed; the onboard lamp and solar data time series indicates that the IR spectrometer did not reach a permanent regime until after several months of operation. The solar measurements at first light and in permanent regime show a difference, which provides an effective wavelength dependent correction factor for the first light spectrum. The SOLSPEC-ISS spectrum obtained in this permanent regime is consistent with the ATLAS 3 spectrum within their combined uncertainties and will be identified in the literature as SOLAR 2rev. We present analysis of this SOLAR 2rev spectrum in terms of its contribution to TSI, the lower photospheric temperature, and comparisons with independently measured IR spectra from ground-based and on-orbit platforms.

  17. Diffusion lengths in irradiated N/P InP-on-Si solar cells

    NASA Technical Reports Server (NTRS)

    Wojtczuk, Steven; Colerico, Claudia; Summers, Geoffrey P.; Walters, Robert J.; Burke, Edward A.

    1996-01-01

    Indium phosphide (InP) solar cells were made on silicon (Si) wafers (InP/Si) by to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. Spire has made N/P InP/Si cells of sizes up to 2 cm by 4 cm with beginning-of-life (BOL) AM0 efficiencies over 13% (one-sun, 28C). These InP/Si cells have higher absolute efficiency and power density after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells after a fluence of about 2e15 1 MeV electrons/sq. cm. In this work, we investigate the minority carrier (electron) base diffusion lengths in the N/P InP/Si cells. A quantum efficiency model was constructed for a 12% BOL AM0 N/P InP/Si cell which agreed well with the absolutely measured quantum efficiency and the sun-simulator measured AM0 photocurrent (30.1 mA/sq. cm). This model was then used to generate a table of AM0 photocurrents for a range of base diffusion lengths. AM0 photocurrents were then measured for irradiations up to 7.7e16 1 MeV electrons/sq. cm (the 12% BOL cell was 8% after the final irradiation). By comparing the measured photocurrents with the predicted photocurrents, base diffusion lengths were assigned at each fluence level. A damage coefficient K of 4e-8 and a starting (unirradiated) base electron diffusion length of 0.8 microns fits the data well. The quantum efficiency was measured again at the end of the experiment to verify that the photocurrent predicted by the model (25.5 mA/sq. cm) agreed with the simulator-measured photocurrent after irradiation (25.7 mA/sq. cm).

  18. Investigation of solar cells fabricated on low-cost silicon sheet materials using 1 MeV electron irradiation

    NASA Technical Reports Server (NTRS)

    Kachare, A. H.; Hyland, S. L.; Garlick, G. F. J.

    1981-01-01

    The use of high energy electron irradiation is investigated as a controlled means to study in more detail the junction depletion layer processes of solar cells made on various low-cost silicon sheet materials. Results show that solar cells made on Czochralski grown silicon exhibit enhancement of spectral response in the shorter wavelength region when irradiated with high energy electrons. The base region damage can be reduced by subsequent annealing at 450 C which restores the degraded longer wavelength response, although the shorter wavelength enhancement persists. The second diode component of the cell dark forward bias current is also reduced by electron irradiation, while thermal annealing at 450 C without electron irradiation can also produce these same effects. Electron irradiation produces small changes in the shorter wavelength spectral responses and junction improvements in solar cells made on WEB, EFG, and HEM silicon. It is concluded that these beneficial effects on cell characteristics are due to the reduction of oxygen associated deep level recombination centers in the N(+) diffused layer and in the junction.

  19. Investigation of solar cells fabricated on low-cost silicon sheet materials using 1 MeV electron irradiation

    NASA Astrophysics Data System (ADS)

    Kachare, A. H.; Hyland, S. L.; Garlick, G. F. J.

    The use of high energy electron irradiation is investigated as a controlled means to study in more detail the junction depletion layer processes of solar cells made on various low-cost silicon sheet materials. Results show that solar cells made on Czochralski grown silicon exhibit enhancement of spectral response in the shorter wavelength region when irradiated with high energy electrons. The base region damage can be reduced by subsequent annealing at 450 C which restores the degraded longer wavelength response, although the shorter wavelength enhancement persists. The second diode component of the cell dark forward bias current is also reduced by electron irradiation, while thermal annealing at 450 C without electron irradiation can also produce these same effects. Electron irradiation produces small changes in the shorter wavelength spectral responses and junction improvements in solar cells made on WEB, EFG, and HEM silicon. It is concluded that these beneficial effects on cell characteristics are due to the reduction of oxygen associated deep level recombination centers in the N(+) diffused layer and in the junction.

  20. Comparison of model estimated and measured direct-normal solar irradiance

    SciTech Connect

    Halthore, R.N.; Schwartz, S.E. [Department of Applied Science, Brookhaven National Laboratory, Upton, New York (United States)] [Department of Applied Science, Brookhaven National Laboratory, Upton, New York (United States); Michalsky, J.J. [Atmospheric Sciences Research Center, State University of New York at Albany (United States)] [Atmospheric Sciences Research Center, State University of New York at Albany (United States); Anderson, G.P. [Phillips Laboratory/Geophysics Directorate, Hanscom Air Force Base, Massachusetts (United States)] [Phillips Laboratory/Geophysics Directorate, Hanscom Air Force Base, Massachusetts (United States); Ferrare, R.A. [Hughes STX Corporation, Lanham, Maryland (United States)] [Hughes STX Corporation, Lanham, Maryland (United States); Holben, B.N. [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)] [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States); Ten Brink, H.M. [Netherlands Energy Research Foundation, ECN, Petten (Netherlands)] [Netherlands Energy Research Foundation, ECN, Petten (Netherlands)

    1997-12-01

    Direct-normal solar irradiance (DNSI), the energy in the solar spectrum incident in unit time at the Earth{close_quote}s surface on a unit area perpendicular to the direction to the Sun, depends only on atmospheric extinction of solar energy without regard to the details of the extinction, whether absorption or scattering. Here we report a set of closure experiments performed in north central Oklahoma in April 1996 under cloud-free conditions, wherein measured atmospheric composition and aerosol optical thickness are input to a radiative transfer model, MODTRAN 3, to estimate DNSI, which is then compared with measured values obtained with normal incidence pyrheliometers and absolute cavity radiometers. Uncertainty in aerosol optical thickness (AOT) dominates the uncertainty in DNSI calculation. AOT measured by an independently calibrated Sun photometer and a rotating shadow-band radiometer agree to within the uncertainties of each measurement. For 36 independent comparisons the agreement between measured and model-estimated values of DNSI falls within the combined uncertainties in the measurement (0.3{endash}0.7{percent}) and model calculation (1.8{percent}), albeit with a slight average model underestimate ({minus}0.18{plus_minus}0.94){percent}; for a DNSI of 839Wm{sup {minus}2} this corresponds to {minus}1.5{plus_minus}7.9Wm{sup {minus}2}. The agreement is nearly independent of air mass and water-vapor path abundance. These results thus establish the accuracy of the current knowledge of the solar spectrum, its integrated power, and the atmospheric extinction as a function of wavelength as represented in MODTRAN 3. An important consequence is that atmospheric absorption of short-wave energy is accurately parametrized in the model to within the above uncertainties. {copyright} 1997 American Geophysical Union

  1. Rational selection of near-extreme coincident weather data with solar irradiation for risk-based air-conditioning design

    Microsoft Academic Search

    Tingyao Chen; Youming Chen; Francis W. H. Yik

    2007-01-01

    The selection of design solar irradiance in the current ASHRAE and CIBSE design handbooks is independent on design dry-bulb and wet-bulb temperatures. The probability that the load would not exceed the system capacity determined on this basis may not match the reliability level that the design weather data were meant to safeguard. Hence, a statistic method was developed for the

  2. Assessment of Heliosat-4 surface solar irradiance derived on the basis of SEVIRI-APOLLO cloud products

    E-print Network

    Boyer, Edmond

    Assessment of Heliosat-4 surface solar irradiance derived on the basis of SEVIRI-APOLLO cloud are crucial for the assessment of SSI. The APOLLO cloud product provided by DLR includes abundant information about the cloud physical and optical properties. The performances of Heliosat-4 when using APOLLO

  3. Use of OCA and APOLLO in Heliosat-4 method for the assessment of surface downwelling solar irradiance

    E-print Network

    Paris-Sud XI, Université de

    are increasing, in particular in the assessment of the direct and diffuse components of the SSI. Attempting-stream and delta-Eddington approximations and MODIS-derived ground albedo. Advanced products describing aerosols, diffuse and direct surface irradiance for use in various domains: solar energy, biomass, agriculture

  4. Defects and annealing studies in 1-Me electron irradiated (AlGa)As-GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Li, S. S.; Wang, W. L.; Loo, R. Y.; Rahilly, W. P.

    1982-01-01

    The deep-level defects and recombination mechanisms in the one-MeV electron irradiated (AlGa)As-GaAs solar cells under various irradiation and annealing conditions are discussed. Deep-level transient spectroscopy (DLTS) and capacitance-voltage (CV) techniques were used to determine the defect and recombination parameters such as energy levels and defect density, carrier capture cross sections and lifetimes for both electron and hole traps as well as hole diffusion lengths in these electron irradiated GaAs solar cells. GaAs solar cells used in this study were prepared by the infinite solution melt liquid phase epitaxial (LPE) technique at Hughes Research Lab., with (Al0.9Ga0.1)-As window layer, Be-diffused p-GaAs layer on Sn-doped n-GaAs or undoped n-GaAs active layer grown on n(+)-GaAs substrate. Mesa structure with area of 5.86x1000 sq cm was fabricated. Three different irradiation and annealing experiments were performed on these solar cells.

  5. Detection of a secular trend in Total Solar Irradiance of + 0.04 % per decade during solar cycles 21 - 23

    NASA Astrophysics Data System (ADS)

    Willson, R. C.

    2004-12-01

    A `piecewise' continuous record of total solar irradiance (TSI) has been made by satellite experiments since November 1978. Assembling a contiguous record from this set of observations is a challenging task due to variations in quality of the different data sets, the limitation that a subtle secular trend might be masked by uncertainties in accuracy, precision and traceability and the necessity of relating the ACRIM1 and ACRIM2 results across a two year gap. The ACRIM approach to constructing a composite TSI record retains maximum precision and traceability by using results published by the science teams of the various experiments without alteration and the Nimbus7/ERB comparisons to link ACRIM1 and ACRIM2. The resulting ACRIM composite TSI demonstrates an upward trend of 0.04 (+/- 0.01) % per decade between activity minima during solar cycles 21-23. [Willson & Mordvinov] Another TSI composite, the `PMOD' [Frohlich & Lean], uses the same set of TSI data in a different approach and does not find a significant trend between minima. The PMOD composite uses TSI proxy models to justify modifying published results and relates ACRIM1&2 results using the overlapping data of the ERBS/ERBE experiment. The absence of a trend in the PMOD composite can be shown to be an artifact of uncorrected ERBS/ERBE degradation during the ACRIM gap. It will be further shown that chromospheric TSI regression (proxy) models are not competitive in accuracy, precision or traceability with satellite TSI observations and their use is therefore counter-indicated in construction of TSI composites. [Willson, R.C., A. V. Mordvinov, JGRL 30, pp. 1199-1202, 2003, Frohlich C., J. Lean, JGRL 25, pp. 4377-4380, 1998

  6. Modeling the ionospheric E and F1 regions: Using SDO-EVE observations as the solar irradiance driver

    NASA Astrophysics Data System (ADS)

    Sojka, Jan J.; Jensen, Joseph; David, Michael; Schunk, Robert W.; Woods, Tom; Eparvier, Frank

    2013-08-01

    ver the altitude range of 90-150 km, in dayside nonauroral regions, ionization is controlled almost entirely by solar ultraviolet irradiance; the response time for ionization during solar exposure is almost instantaneous, and likewise, the time scale for recombination into neutral species is very fast when the photoionizing source is removed. Therefore, if high-resolution solar spectral data are available, along with accurate ionization cross sections as a function of wavelength, it should be possible to model this ionospheric region with greater accuracy. The Extreme Ultraviolet Variability Experiment (EVE) instrument on the National Aeronautics and Space Administration Solar Dynamics Observatory (SDO) satellite, launched in February 2010, is intended to provide just such solar data, at high resolution in both wavelength and time cadence. We use the Utah State University time-dependent ionospheric model to assess the sensitivity in modeling that this solar irradiance data provide, under quiet solar conditions as well as during X-class flares. The sensitivity studies show that the E and F1 regions, as well as the valley region, are strongly dependent upon wavelength in both electron density and ion composition.

  7. Solar EUV Monitor (SEM) absolute irradiance measurements and how they are affected by choice of reference spectrum

    NASA Astrophysics Data System (ADS)

    Wieman, Seth R.; Judge, Darrell L.; Didkovsky, Leonid V.

    2011-10-01

    The SOHO/CELIAS Solar EUV Monitor (SEM) has measured absolute extreme ultraviolet (EUV) solar irradiance nearly continuously over a 15 year period that includes two solar cycle minima, 22/23 (1996) and 23/24 (2008). Calibration of the SEM flight instrument and verification of the data have been maintained through measurements from a series of sounding rocket calibration underflights that have included a NIST calibrated SEM clone instrument as well as a Rare Gas Ionization Cell (RGIC) absolute detector. From the beginning of SEM data collection in 1996, the SOLERS 22 fixed reference solar spectrum has been used to calculate absolute EUV flux values from SEM raw data. Specifically, the reference spectrum provides a set of weighting factors for determining a weighted average for the wavelength dependent SEM response. The spectrum is used for calculation of the second order contamination in the first order channel signals, and for the comparison between SEM flux measurements with broader-band absolute RGIC measurements. SOHO/SEM EUV flux measurements for different levels of solar activity will be presented to show how the choice of reference spectra now available affects these SEM data. Both fixed (i.e. SOLERS 22) and non-fixed (Solar Irradiance Platform/Solar 2000 and SDO/EVE/MEGS) reference spectra have been included in this analysis.

  8. Solar/Stellar Irradiance Comparison Experiment (SOLSTICE) on the Upper Atmosphere Research Satellite (UARS)

    NASA Technical Reports Server (NTRS)

    Rottman, Gary J.; Woods, Thomas N.; London, Julius; Ayres, Thomas R.

    2003-01-01

    A final report on the operational activities related to the UARS Solar Stellar irradiance Comparison Experiment (SOLSTICE) is presented. Scientific activities of SOLSTICE has also been supported. The UARS SOLSTICE originated at the University of Colorado in 1981. One year after the UARS launch in 1991, the operations and research support activities for SOLSTICE were moved to the High Altitude Observatory (HAO) of the National Center for Atmospheric Research (NCAR). The SOLSTICE program continued at HAO with the National Science Foundation, and after four years, it was moved once again back to the University of Colorado. At the University after 1997 this subject grant was issued to further extend the operations activities from July 2001 through September 2002. Although this is a final report for one particular activity, in fact the SOLSTICE operations activity -first at the University, then at HAO, and now again at the University -has continued in a seamless fashion.

  9. Synthesis of magnetic graphene oxide-TiO2 and their antibacterial properties under solar irradiation

    NASA Astrophysics Data System (ADS)

    Chang, Ying-Na; Ou, Xiao-Ming; Zeng, Guang-Ming; Gong, Ji-Lai; Deng, Can-Hui; Jiang, Yan; Liang, Jie; Yuan, Gang-Qiang; Liu, Hong-Yu; He, Xun

    2015-07-01

    Titanium dioxide (TiO2) has been intensively researched and increasingly used as antibacterial agent, but it suffers from separation inconvenience. Its effective removal from water after reaction while maintaining its high antibacterial activity becomes necessary. In this work, it was the first time the magnetic graphene oxide-TiO2 (MGO-TiO2) composites were prepared through a simple synthesis method. The results indicated that MGO-TiO2 exhibited a good antibacterial activity against Escherichia coli. MGO-TiO2 was found to almost completely inactivate the E. coli within 30 min under solar irradiation. The effect of inorganic ions present in E. coli suspension was also evaluated. Compared with other ions, HCO3- and HPO42- had a greater influence on the antibacterial property.

  10. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the around in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 W/sq m per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  11. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the ground in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 Wm(exp -2) per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  12. The Use of Meteosat Second Generation Satellite Data Within A New Type of Solar Irradiance Calculation Scheme

    NASA Astrophysics Data System (ADS)

    Mueller, R. W.; Beyer, H. G.; Cros, S.; Dagestad, K. F.; Dumortier, D.; Ineichen, P.; Hammer, A.; Heinemann, D.; Kuhlemann, R.; Olseth, J. A.; Piernavieja, G.; Reise, C.; Schroedter, M.; Skartveit, A.; Wald, L.

    1-University of Oldenburg, 2-University of Appl. Sciences Magdeburg, 3-Ecole des Mines de Paris, 4-University of Bergen, 5-Ecole Nationale des Travaux Publics de l'Etat, 6-University of Geneva, 7-Instituto Tecnologico de Canarias, 8-Fraunhofer Institute for Solar Energy Systems, 9-German Aerospace Center Geostationary satellites such as Meteosat provide cloud information with a high spatial and temporal resolution. Such satellites are therefore not only useful for weather fore- casting, but also for the estimation of solar irradiance since the knowledge of the light reflected by clouds is the basis for the calculation of the transmitted light. Additionally an the knowledge of atmospheric parameters involved in scattering and absorption of the sunlight is necessary for an accurate calculation of the solar irradiance. An accurate estimation of the downward solar irradiance is not only of particular im- portance for the assessment of the radiative forcing of the climate system, but also necessary for an efficient planning and operation of solar energy systems. Currently, most of the operational calculation schemes for solar irradiance are semi- empirical. They use cloud information from the current Meteosat satellite and clima- tologies of atmospheric parameters e.g. turbidity (aerosols and water vapor). The Me- teosat Second Generation satellites (MSG, to be launched in 2002) will provide not only a higher spatial and temporal resolution, but also the potential for the retrieval of atmospheric parameters such as ozone, water vapor and with restrictions aerosols. With this more detailed knowledge about atmospheric parameters it is evident to set up a new calculation scheme based on radiative transfer models using the retrieved atmospheric parameters as input. Unfortunately the possibility of deriving aerosol in- formation from MSG data is limited. As a cosequence the use of data from additional satellite instruments ( e.g. GOME/ATSR-2) is neeeded. Within this presentation a new type of the solar irradiance calculation scheme is de- scribed. It is based on the integrated use of a radiative transfer model (RTM), whereas the information of the atmospheric parameters retrieved from satellites (MSG and GOME/ATSR-2) will be used as input for the RTM. First comparisons between calcu- lated and measured solar irradiance are presented. The improvements linked with the usage of the new calculation scheme are discussed, taking into account the benefits and limitations of the new method and the MSG satellite.

  13. The Effect of Solar Irradiated Vibrio cholerae on the Secretion of Pro-Inflammatory Cytokines and Chemokines by the JAWS II Dendritic Cell Line In Vitro.

    PubMed

    Ssemakalu, Cornelius Cano; Ubomba-Jaswa, Eunice; Motaung, Keolebogile Shirley; Pillay, Michael

    2015-01-01

    The use of solar irradiation to sterilize water prior to its consumption has resulted in the reduction of water related illnesses in waterborne disease endemic communities worldwide. Currently, research on solar water disinfection (SODIS) has been directed towards understanding the underlying mechanisms through which solar irradiation inactivates the culturability of microorganisms in water, enhancement of the disinfection process, and the health impact of SODIS water consumption. However, the immunological consequences of SODIS water consumption have not been explored. In this study, we investigated the effect that solar irradiated V. cholerae may have had on the secretion of cytokines and chemokines by the JAWS II dendritic cell line in vitro. The JAWS II dendritic cell line was stimulated with the different strains of V. cholerae that had been: (i) prepared in PBS, (ii) inactivated through a combination of heat and chemical, (iii) solar irradiated, and (iv) non-solar irradiated, in bottled water. As controls, LPS (1 ?g/ml) and CTB (1 ?g/ml) were used as stimulants. After 48 hours of stimulation the tissue culture media from each treatment was qualitatively and quantitatively analysed for the presence of IL-1?, IL-1?, IL-6, IL-7, IL-10, IL-12p40, IL-12p70, IL-15, MIP-1?, MIP-1?, MIP-2, RANTES, TNF-?, IL-23 and IL-27. Results showed that solar irradiated cultures of V. cholerae induced dendritic cells to secrete significant (p<0.05) levels of pro-inflammatory cytokines in comparison to the unstimulated dendritic cells. Furthermore, the amount of pro-inflammatory cytokines secreted by the dendritic cells in response to solar irradiated cultures of V. cholerae was not as high as observed in treatments involving non-solar irradiated cultures of V. cholerae or LPS. Our results suggest that solar irradiated microorganisms are capable of inducing the secretion of pro-inflammatory cytokines and chemokines. This novel finding is key towards understanding the possible immunological consequences of consuming SODIS treated water. PMID:26066787

  14. The Effect of Solar Irradiated Vibrio cholerae on the Secretion of Pro-Inflammatory Cytokines and Chemokines by the JAWS II Dendritic Cell Line In Vitro

    PubMed Central

    Ssemakalu, Cornelius Cano; Ubomba-Jaswa, Eunice; Motaung, Keolebogile Shirley; Pillay, Michael

    2015-01-01

    The use of solar irradiation to sterilize water prior to its consumption has resulted in the reduction of water related illnesses in waterborne disease endemic communities worldwide. Currently, research on solar water disinfection (SODIS) has been directed towards understanding the underlying mechanisms through which solar irradiation inactivates the culturability of microorganisms in water, enhancement of the disinfection process, and the health impact of SODIS water consumption. However, the immunological consequences of SODIS water consumption have not been explored. In this study, we investigated the effect that solar irradiated V. cholerae may have had on the secretion of cytokines and chemokines by the JAWS II dendritic cell line in vitro. The JAWS II dendritic cell line was stimulated with the different strains of V. cholerae that had been: (i) prepared in PBS, (ii) inactivated through a combination of heat and chemical, (iii) solar irradiated, and (iv) non-solar irradiated, in bottled water. As controls, LPS (1 ?g/ml) and CTB (1 ?g/ml) were used as stimulants. After 48 hours of stimulation the tissue culture media from each treatment was qualitatively and quantitatively analysed for the presence of IL-1?, IL-1?, IL-6, IL-7, IL-10, IL-12p40, IL-12p70, IL-15, MIP-1?, MIP-1?, MIP-2, RANTES, TNF-?, IL-23 and IL-27. Results showed that solar irradiated cultures of V. cholerae induced dendritic cells to secrete significant (p<0.05) levels of pro-inflammatory cytokines in comparison to the unstimulated dendritic cells. Furthermore, the amount of pro-inflammatory cytokines secreted by the dendritic cells in response to solar irradiated cultures of V. cholerae was not as high as observed in treatments involving non-solar irradiated cultures of V. cholerae or LPS. Our results suggest that solar irradiated microorganisms are capable of inducing the secretion of pro-inflammatory cytokines and chemokines. This novel finding is key towards understanding the possible immunological consequences of consuming SODIS treated water. PMID:26066787

  15. Total ozone column, water vapour and aerosol effects on erythemal and global solar irradiance in Marsaxlokk, Malta

    NASA Astrophysics Data System (ADS)

    Bilbao, Julia; Román, Roberto; Yousif, Charles; Mateos, David; de Miguel, Argimiro

    2014-12-01

    Observations of erythemal (UVER; 280-400 nm) and total solar shortwave irradiance (SW; 305-2800 nm), total ozone column (TOC), water vapour column (w), aerosol optical depth (AOD) and Ångström exponent (?) were carried out at Marsaxlokk, in south-east Malta. These measurements were recorded during a measurement campaign between May and October 2012, aimed at studying the influence of atmospheric compounds on solar radiation transfer through the atmosphere. The effects of TOC, AOD and w on UVER and SW (global, diffuse and direct) irradiance were quantified using irradiance values under cloud-free conditions at different fixed solar zenith angles (SZA). Results show that UVER (but not SW) irradiance correlates well with TOC. UVER variations ranged between -0.24% DU-1 and -0.32% DU-1 with all changes being statistically significant. Global SW irradiance varies with water vapour column between -2.44% cm-1 and -4.53% cm-1, these results proving statistically significant and diminishing when SZA increases. The irradiance variations range between 42.15% cm-1 and 20.30% cm-1 for diffuse SW when SZA varies between 20° and 70°. The effect of aerosols on global UVER is stronger than on global SW. Aerosols cause a UVER reduction of between 28.12% and 52.41% and a global SW reduction between 13.46% and 41.41% per AOD550 unit. Empirical results show that solar position plays a determinant role, that there is a negligible effect of ozone on SW radiation, and stronger attenuation by aerosol particles in UVER radiation.

  16. Photodegradation of endocrine disrupting chemical nonylphenol by simulated solar UV-irradiation.

    PubMed

    Neam?u, Mariana; Frimmel, Fritz H

    2006-10-01

    The photolysis of nonylphenol (NP) was investigated using a solar simulator in the absence/presence of dissolved organic matter (DOM), HCO3-, NO3- and Fe(III) ions. The effects of different parameters such as initial pH, initial concentration of substrate, temperature, and the effect of hydrogen peroxide concentration on photodegradation of nonylphenol in aqueous solution have been assessed. The results indicate that the oxidation rate increases in the presence of H2O2, Fe(III) and DOM with dissolved organic carbon concentrations not higher than 3 mg L(-1). Phenol, 1,4-dihydroxylbenzene and 1,4-benzoquinone were identified as intermediate products of photodegradation of nonylphenol, through an HPLC method. In addition, the disappearance of the estrogenic activity of nonylphenol during irradiation using YES test was investigated. Based upon the YES test results, there was a strong decrease of estrogenic activity of nonylphenol after 80 h irradiation in the presence of hydrogen peroxide. PMID:16765422

  17. IR Spectroscopy and Photo-Chemistry of Extraterrestrial Ices

    NASA Technical Reports Server (NTRS)

    Bernstein, Max P.; Mastrapa, Rachel; Elsila, Jamie; Sandford, Scott

    2005-01-01

    Dense molecular clouds from which planetary systems form and the outer Solar System are both cold environments dominated by ices. Infrared (IR) spectroscopy is used to probe these ices, but the IR absorptions of molecules depend on the conditions. As a result appropriate lab data is needed to correctly fit spectra of extraterrestrial ices. Such fits have shown that most of these ices are composed primarily of H2O, but also contain 1-10 percent of other simple molecules such as CO2, CO, CH4, & NH3;. We shall present near IR spectra of ice mixtures of relevance to icy outer Solar System bodies and show that they still hold surprises, such as the Cheshire cat-like CO2 (2v3) overtone near 2.134 micrometers (4685 cm-1) that is absent from spectra of pure CO2 but present in H2O-CO2 mixtures.

  18. A search strategy for SETI - The search for extraterrestrial intelligence

    NASA Technical Reports Server (NTRS)

    Billingham, J.; Wolfe, J.; Edelson, R.; Gulkis, S.; Olsen, E.; Oliver, B.; Tarter, J.; Seeger, C.

    1980-01-01

    A search strategy is proposed for the detection of signals of extraterrestrial intelligent origin. It constitutes an exploration of a well defined volume of search space in the microwave region of the spectrum and envisages the use of a combination of sky survey and targeted star approaches. It is predicated on the use of existing antennas equipped with sophisticated multichannel spectrum analyzers and signal processing systems operating in the digital mode. The entire sky would be surveyed between 1 and 10 GHz with resolution bin widths down to 32 Hz. More than 700 nearby solar type stars and other selected interesting directions would be searched between 1 GHz and 3 GHz with bin widths down to 1 Hz. Particular emphasis would be placed on those solar type stars that are within 20 light years of earth.

  19. SETI - The search for extraterrestrial intelligence - Plans and rationale

    NASA Technical Reports Server (NTRS)

    Wolfe, J. H.; Billingham, J.; Edelson, R. E.; Crow, R. B.; Gulkis, S.; Olsen, E. T.; Oliver, B. M.; Peterson, A. M.

    1981-01-01

    The methodology and instrumentation of a 10 yr search for extraterrestrial intelligence (SETI) program by NASA, comprising 5 yr for instrumentation development and 5 yr for observations, is described. A full sky survey in two polarizations between 1.2 and 10 GHz with resolution binwidths down to 32 Hz, and a two polarization can between 1.2-3 GHz with resolution binwidths down to 1 Hz of 700 nearby solar type stars within 20 light years of earth will extend the sensitivity of previous surveys by 300 times and cover 20,000 times more frequency space. EM signals are perceived as the only means for detecting life outside the solar system, and the SETI effort is driven by the empirical experience that once a physical process has been observed to occur, its occurrence elsewhere is assured. Further discussion is given of the history of searches for life in the Universe, the SETI search strategy, instrumentation, and signal identification.

  20. Induction of UV photoproducts and DNA damage by solar simulator UV irradiation

    SciTech Connect

    Wolfreys, A.; Henderson, L. [Unilever Research, Sharnbrook, Bedford (United Kingdom); Clingen, P. [Univ. of Sussex, Falmer, Brigthon (United Kingdom)

    1997-10-01

    The recent increased incidence of skin cancer and the depletion of the ozone layer has increased interest in the ultraviolet (UV) component of natural sunlight and its role in the induction of skin cancer. Previous research on UV radiation has concentrated on UVC (254nm) but, as only UVB and UVA are present in natural sunlight, its relevance is unknown. We have investigated the induction of two forms of direct DNA damage - the pyrimidine dimer and the (6-4) photoproduct - in human DNA repair deficient XP-G (Xeroderma pigmentosum group G) lymphoblastoid cells following exposure to simulated sunlight. As exposure to natural sunlight is highly variable, a solar simulator lamp was used which is known to mimic natural sunlight at midday in Central Europe. Cells were irradiated on ice to minimise DNA repair and the relative induction of pyrimidine dimers and (6-4) photoproducts was measured using specific monoclonal antibodies and a computer assisted image analysis system. A time dependent increase in both cyclobutane dimer and (6-4) photoproduct antibody binding sites was seen. The increases in pyrimidine dimer and (6-4) photoproduct antibody binding sites differed to that reported with natural sunlight in the UK but was similar to that seen with a similar solar simulator lamp.

  1. Artificial neural networks for the generation of direct normal solar annual irradiance synthetic series

    NASA Astrophysics Data System (ADS)

    Rodrigo, J.; Hontoria, L.; Almonacid, F.; Fernández, Eduardo F.; Rodrigo, P. M.; Pérez-Higueras, P. J.

    2012-10-01

    The use of concentrators implies that CPV systems only work with the Direct Normal Irradiance (DNI). So it is necessary to know DNI data in order to estimate the energy that will be produced by the system, perform economic analysis, supervise plant operation, etc. However, DNI Typical Meteorological Year datasets are expensive and rarely available due to the cost and sophistication of measurement devices and data processing requirements. Particularly, there is a lack of data on the Sunbelt countries, which are more favorable for the use of CPV. In this work, an artificial neural network is used for the generation of DNI hourly time series for some Spanish locations. The model was trained and tested with different locations and different year's data. Although several authors have proposed different methods for the generation of solar radiation synthetic series, these methods are for global radiation and flat panel, nevertheless, we calculate them for direct normal solar radiation and used for CPV systems. A Multilayer Perceptron is explained, looking over the first rudimentary initial version and the last more elaborated final version. Finally, an application of this methodology is presented.

  2. The Belgian DIARAD Total Solar Irradiance Observations, Historical Objectives, Achievements and Particularities.

    NASA Astrophysics Data System (ADS)

    Crommelynck, D.

    2007-12-01

    The origin of the Total Solar Irradiance (TSI) observations at the Royal Meteorological Institute of Belgium is the will to monitor the Earth Radiation Budget (ERB) whereoff the TSI is one of the terms, the two others are the reflected solar radiation and the Earth emitted radiation actually measured operationnaly by the Geostationnary Earth Radiation Budget (GERB) experiment on board of EUMETSAT MSG. This concerns atmospheric physics as well as climate. The new design of a differential absolute radiometer (DIARAD) characterised in air as well as in vacuum, led to its incorporation in the set of instruments defining the World Radiometric Reference (WRR); adapted for space, it flew repetitively on the space shuttle as well as on the european retrievable carrier (EURECA). Since 1996 DIARAD operates contineously without any failure from VIRGO on SOHO. Our strategic principles required to insure a long range high quality TSI data base are developed . It incorporates the usage of Space Absolute Radiometric Reference (SARR) coefficients to normalise the observations in time. The compared characteristics of DIARAD and PMO instruments are presented as well as the chronological events and behaviours of the radiometers flying on VIRGO/SOHO. It is concluded that a minimum of three simultaneous flying radiometers are required to guarantee the value of the TSI data base.

  3. Investigation of the effect of contrails on global irradiance and solar energy production

    NASA Astrophysics Data System (ADS)

    Weihs, Philipp; Rennhofer, Marcus; Baumgartner, Dietmar; Wagner, Jochen; Laube, Wolfgang; Gadermaier, Josef

    2013-04-01

    In the present study we investigate the effect of contrails on global shortwave radiation and on Photovoltaic module performance. This investigation is performed using continuous hemispherical fish eye photographs of the sky, diffuse and direct shortwave measurements and short circuit current measurements of a-Si, c-Si and CdTe PV modules. These measurements have been performed at the solar observatory Kanzelhöhe (1540 m.a.s.l) located in the southern part of Austria during a period of one and half year. The time resolution of the measurements is one minute, which allows to accurately follow the formation-eventually the disappearance- or the movement of the contrails in the sky. Using the fish eye photographs we identified clear sky days with a high contrail persistence. We especially look at situations where the contrails were shading the sun. Results show that contrails shading the sun may reduce the global radiation by up to 60%. In general we however observe that during days with a high contrail persistence the diffuse irradiance is slightly increased. Finally a statistic of the contrail persistence during the period of measurement is presented and conclusions as to the relevance for the solar energy production are drawn.

  4. Extraterrestrial intelligence - An observational approach

    NASA Technical Reports Server (NTRS)

    Murray, B.; Gulkis, S.; Edelson, R. E.

    1978-01-01

    The article surveys present and proposed search techniques for extraterrestrial intelligence in terms of technological requirements. It is proposed that computer systems used along with existing antennas may be utilized to search for radio signals over a broad frequency range. A general search within the electromagnetic spectrum would explore frequency, received power flux, spatial locations, and modulation. Previous SETI projects (beginning in 1960) are briefly described. An observation project is proposed in which the earth's rotational motion would scan the antenna beam along one declination circle in 24 hours. The 15 degree beam width would yield a mapping of 75% of the sky in an 8-day period if the beam were shifted 15 degrees per day. With the proposed instrument parameters, a sensitivity of about 10 to the -21 watt/sq m is achieved at a 0 degree declination and 1.5 GHz. In a second phase, a 26 m antenna would yield an HPBW of 0.8 degrees at 1 GHz and 0.03 degrees at 25 GHz. It is noted that the described technology would provide secondary benefits for radio astronomy, radio communications, and other fields.

  5. Solar EUV Irradiance Measurements by the Auto-Calibrating EUV Spectrometers (SolACES) Aboard the International Space Station (ISS)

    NASA Astrophysics Data System (ADS)

    Schmidtke, G.; Nikutowski, B.; Jacobi, C.; Brunner, R.; Erhardt, C.; Knecht, S.; Scherle, J.; Schlagenhauf, J.

    2014-05-01

    SolACES is part of the ESA SOLAR ISS mission that started aboard the shuttle mission STS-122 on 7 February 2008. The instrument has recorded solar extreme ultraviolet (EUV) irradiance from 16 to 150 nm during the extended solar activity minimum and the beginning solar cycle 24 with rising solar activity and increasingly changing spectral composition. The SOLAR mission has been extended from a period of 18 months to > 8 years until the end of 2016. SolACES is operating three grazing incidence planar grating spectrometers and two three-current ionization chambers. The latter ones are considered as primary radiometric detector standards. Re-filling the ionization chambers with three different gases repeatedly and using overlapping band-pass filters, the absolute EUV fluxes are derived in these spectral intervals. This way the serious problem of continuing efficiency changes in space-borne instrumentation is overcome during the mission. Evaluating the three currents of the ionization chambers, the overlapping spectral ranges of the spectrometers and of the filters plus inter-comparing the results from the EUV photon absorption in the gases with different absorption cross sections, there are manifold instrumental possibilities to cross-check the results providing a high degree of reliability to the spectral irradiance derived. During the mission a very strong up-and-down variability of the spectrometric efficiency by orders of magnitude is observed. One of the effects involved is channeltron degradation. However, there are still open questions on other effects contributing to these changes. A survey of the measurements carried out and first results of the solar spectral irradiance (SSI) data are presented. Inter-comparison with EUV data from other space missions shows good agreement such that the international effort has started to elaborate a complete set of EUV-SSI data taking into account all data available from 2008 to 2013.

  6. Evolution of Chromospheric Structures: How Chromospheric Structures Contribute to the Solar HE II 30.4 Nanometer Irradiance and Variability

    NASA Astrophysics Data System (ADS)

    Worden, John; Woods, Thomas N.; Neupert, Werner M.; Delaboudinière, Jean-Pierre

    1999-02-01

    The bright He II 30.4 nm solar emission is an important energy source for ionization and heating of the Earth's upper atmosphere. The analysis of the Solar and Heliospheric Observatory (SOHO) Extreme-Ultraviolet Imaging Telescope (EIT) He II 30.4 nm images provides an improved understanding of how the solar surface structures, i.e., plage, enhanced network (plage remnants), active network, and the quiet chromosphere, contribute to the solar He II 30.4 nm irradiance and its variability. We first normalize the intensities of each image to the background quiet-chromosphere intensity with a global fit that preferentially weights network cell intensities. The resulting quiet-chromosphere intensity scale is stable to within 0.7% (1 ?) over the 2 yr data set. The plage, enhanced-network, active-network, and quiet-chromosphere structures are then identified on each EIT He II image with an algorithm that uses criteria of intensity, size, filling factor, and continuity. This decomposition leads to time series of structure area and integrated intensity, their spatial distribution on the solar disk, and their intensity contrast relative to the quiet-chromosphere intensity; thus, these time series show how the solar surface structures contribute to the He II 30.4 nm irradiance. For example, we find that the active network contributes as much as the plage and enhanced network to the solar He II 30.4 nm irradiance variability during solar minimum. Conversely, the quiet-chromosphere irradiance does not vary during this time period; thus we conclude that long-term He II 30.4 nm irradiance variations can be traced purely to magnetic activity during this time period. We also find that the plage, enhanced-network, active-network, and quiet-network intensity contrasts, relative to the quiet chromosphere and averaged over the full area of each structure, are 4.8, 3.3, 2.1, and 1.6, respectively, and these contrasts remain essentially constant with time.

  7. Estimation of global solar UV index from UV-B irradiance measured with a narrow-band UV-B radiometer

    NASA Astrophysics Data System (ADS)

    Takeshita, Shu; Sasaki, Masako

    2005-08-01

    The global solar UV index is an indicator for notifying the level of harmful solar ultraviolet radiation reaching the surface of the earth and the general public. It was proposed by the WHO/WMO/UNEP/ICNIRP and was standardized by the CIE in 2003. This index is derived from the product of the spectral solar UV irradiance from 250 to 400 nm and the CIE standard of reference erythema spectrum. For calculation of the UV index, the measurement of spectral solar UV irradiance is needed. Spectral radiometry is the best method of measurement of solar UV irradiance, however spectral radiometers are cost prohibitive. On the other hand, a narrow-band solar UV-B radiometer is widely used for measurement of solar UV-B irradiance in the world. The Tokai Solar Radiation Monitoring Network, and the UV Monitoring Network-Japan performed by the National Institute for Environmental Studies are two examples of monitoring networks using narrow-band solar UV-B radiometer in Japan. In this paper an estimation method of the UV index from the measured UV-B irradiance with the narrow-band UV-B radiometer.

  8. Wavelength dependence of solar irradiance enhancement during X-class flares and its influence on the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Huang, Yanshi; Richmond, Arthur D.; Deng, Yue; Chamberlin, Phillip C.; Qian, Liying; Solomon, Stanley C.; Roble, Raymond G.; Xiao, Zuo

    2014-08-01

    The wavelength dependence of solar irradiance enhancement during flare events is one of the important factors in determining how the Thermosphere-Ionosphere (T-I) system responds to flares. To investigate the wavelength dependence of flare enhancement, the Flare Irradiance Spectral Model (FISM) was run for 61 X-class flares. The absolute and the percentage increases of solar irradiance at flare peaks, compared to pre-flare conditions, have clear wavelength dependences. The 0-14 nm irradiance increases much more (~680% on average) than that in the 14-25 nm waveband (~65% on average), except at 24 nm (~220%). The average percentage increases for the 25-105 nm and 122-190 nm wavebands are ~120% and ~35%, respectively. The influence of 6 different wavebands (0-14 nm, 14-25 nm, 25-105 nm, 105-120 nm, 121.56 nm, and 122-175 nm) on the thermosphere was examined for the October 28th, 2003 flare (X17-class) event by coupling FISM with the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) under geomagnetically quiet conditions (Kp=1). While the enhancement in the 0-14 nm waveband caused the largest enhancement of the globally integrated solar heating, the impact of solar irradiance enhancement on the thermosphere at 400 km is largest for the 25-105 nm waveband (EUV), which accounts for about 33 K of the total 45 K temperature enhancement, and ~7.4% of the total ~11.5% neutral density enhancement. The effect of 122-175 nm flare radiation on the thermosphere is rather small. The study also illustrates that the high-altitude thermospheric response to the flare radiation at 0-175 nm is almost a linear combination of the responses to the individual wavebands. The upper thermospheric temperature and density enhancements peaked 3-5 h after the maximum flare radiation.

  9. Impact of aerosols on the forecast accuracy of solar irradiance calculated by a numerical weather prediction model

    NASA Astrophysics Data System (ADS)

    Shimose, Ken-ichi; Ohtake, Hideaki; Fonseca, Joao Gari da Silva; Takashima, Takumi; Oozeki, Takashi; Yamada, Yoshinori

    2014-10-01

    The impact of aerosols on the forecast accuracy of solar irradiance calculated by a fine-scale, one day-ahead, and operational numerical weather prediction model (NWP) is investigated in this study. In order to investigate the impact of aerosols only, the clear sky period is chosen, which is defined as when there are no clouds in the observation data and in the forecast data at the same time. The evaluation of the forecast accuracy of the solar irradiance is done at a single observation point that is sometimes affected by aerosol events. The analysis period is one year from April 2010 to March 2011. During the clear sky period, the root mean square errors (RMSE) of the global horizontal irradiance (GHI), direct normal irradiance (DNI), and diffuse horizontal irradiance (DHI) are 40.0 W m-2, 84.0 Wm-2, and 47.9 W m-2, respectively. During one extreme event, the RMSEs of the GHI, DNI, and DHI are 70.1 W m-2, 211.6 W m-2, and 141.7 W m-2, respectively. It is revealed that the extreme events were caused by aerosols such as dust or haze. In order to investigate the impact of the aerosols, the sensitivity experiments of the aerosol optical depth (AOD) for the extreme events are executed. The best result is obtained by changing the AOD to 2.5 times the original AOD. This changed AOD is consistent with the satellite observation. Thus, it is our conclusion that an accurate aerosol forecast is important for the forecast accuracy of the solar irradiance.

  10. Observations of Total Solar Irradiance indicate a + 0.04 % per decade trend during solar cycles 21 - 23

    NASA Astrophysics Data System (ADS)

    Willson, R. C.

    2004-12-01

    Continuous Total solar irradiance (TSI) observations have been made by satellite experiments since late 1978. A precise, contiguous composite TSI can be derived for the past 26 years by relating these results through consecutive overlapping observations. A crucial issue for a composite is the relationship between ACRIM1 and ACRIM2 results across the two year gap between them. This can be established by using one of the two overlapping data sets, the Nimbus7/ERB or ERBS/ERBE. The choice is important because the effects on the composite are significantly different. The ACRIM composite uses unaltered published results and the Nimbus7/ERB overlapping comparisons to link ACRIM1 and ACRIM2. The most significant feature of the ACRIM composite for climate change is an upward trend of 0.04 (+/- 0.01) % per decade between activity minima during solar cycles 21-23. [Willson & Mordvinov] TSI composites using the ERBS/ERBE data to link ACRIM1&2 results, such as the well known PMOD of Frohlich & Lean, use the same TSI data sets in a different approach but do not find a significant trend between minima. The absence of a trend in such ERBS/ERBE-based composites can be shown to be an artifact of uncorrected ERBS/ERBE degradation during the ACRIM1-ACRIM2 `gap'.There are other differences between the ACRIM and PMOD composites, driven principally by the PMOD's use of TSI proxy models to justify modifying the published results of ACRIM1 and Nimbus7/ERB. TSI regression (proxy) models based on chromospheric spectral features are not competitive in accuracy, precision or traceability with satellite TSI observations and are therefore likely to cause spurious effects when used in the construction of TSI composites. The TSI record has been sustained by overlapping, redundant experiments using their level of measurement precision to sustain longer term traceability. This TSI monitoring strategy is essential for continuity in the future because the uncertainty of current satellite sensors (~ 0.1 %) is an order of magnitude too large to detect subtle long term TSI variations of potential climate change significance. [Willson, R.C., A. V. Mordvinov, JGRL 30, pp. 1199-1202, 2003, Frohlich C., J. Lean, JGRL 25, pp. 4377-4380, 1998

  11. STABLE ISOTOPIC RESPONSE TO THE LATE EOCENE EXTRATERRESTRIAL IMPACT EVENTS

    E-print Network

    STABLE ISOTOPIC RESPONSE TO THE LATE EOCENE EXTRATERRESTRIAL IMPACT EVENTS by AIMEE E PUSZ A thesis to the Late Eocene Extraterrestrial Impact Events by AIMEE ELIZABETH PUSZ Thesis Director: Dr. Kenneth G

  12. CONTROL ID: 1484811 TITLE: Infrared Spectroscopy of Extraterrestrial Materials

    E-print Network

    Rossman. George R.

    CONTROL ID: 1484811 TITLE: Infrared Spectroscopy of Extraterrestrial Materials AUTHORS (FIRST NAME are measuring the infrared spectra of a wide range of extraterrestrial materials in the laboratory. The goals

  13. On the relationship between cardboard burning in a sunshine recorder and the direct solar irradiance.

    NASA Astrophysics Data System (ADS)

    Sanchez, A.; Calbó, J.; González, J. A.

    2012-04-01

    Since the end of XIX century, the Campbell-Stokes recorder (CSR) has been the instrument used to measure the insolation (hours of sunshine during per day). Due to the large number of records that exist worldwide (some of them extending over more than 100 years), valuable climatic information can be extracted from them. There are various articles that relate the insolation with the cloudiness and the global solar irradiation (Angstrom-Prescott type formulas). Theoretically, the insolation is defined as the number of hours that direct solar irradiance (DSI) exceeds 120 W/m2, thus corresponding to the total length of the burning in the bands. The width of the burn has not been well studied, so the aim of this research is to relate this width, first with the DSI and then, with other variables. The research was carried out in Girona (NE Spain) for a period extending since February 2011. A CSR from Thies Clima and a pyrheliometer from Kipp&Zonen were used to measure insolation and the direct solar irradiance. Other meteorological variables were also stored for the study. For each band, we made two independent measurements of the width of the burn every 10 minutes: first, we measured directly the width of the perforated portion of the burn; second, we measured the width of the burn after applying a digital image process that increases the contrast of the burn. The burn in a band has a direct relationship with the DSI. Specifically, correlation coefficients of the perforation width and the burning width with DSI were 0.838 and 0.864 respectively. However, we found that there are times when despite of DSI is as high as 400 W/m2 (i.e. much greater than 120 W/m2), there is no burn in the band. Contrarily, sometimes a burn occurs with almost no DSI. Furthermore, a higher DSI does not always correspond to a wider burn of the band. Because of this, we consider that characteristics of band burns must also depend on other meteorological variables (temperature, humidity...). The physical characteristics of the heliograph and of the cardboard from which the bands are made may also have an important role in this relationship. The method was applied to a limited series of bands so the results and conclusions are preliminary. The first conclusion is the lack of accuracy that has the threshold value of 120 W/m2 and the difficulty of giving a single value of this threshold. The sudden changes and intermittent weather conditions, combined with the poor temporal resolution of the measure of the burn width, reduce the correlation between burn and DSI. For further research aimed at the study of the behavior of the insolation due to the changing concentration of aerosols in the atmosphere, we need to increase the number of burned sunshine bands and to describe with more accuracy the limitations of heliographs.

  14. Advanced Curation of Current and Future Extraterrestrial Samples

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.

    2013-01-01

    Curation of extraterrestrial samples is the critical interface between sample return missions and the international research community. Curation includes documentation, preservation, preparation, and distribution of samples. The current collections of extraterrestrial samples include: Lunar rocks / soils collected by the Apollo astronauts Meteorites, including samples of asteroids, the Moon, and Mars "Cosmic dust" (asteroid and comet particles) collected by high-altitude aircraft Solar wind atoms collected by the Genesis spacecraft Comet particles collected by the Stardust spacecraft Interstellar dust collected by the Stardust spacecraft Asteroid particles collected by the Hayabusa spacecraft These samples were formed in environments strikingly different from that on Earth. Terrestrial contamination can destroy much of the scientific significance of many extraterrestrial materials. In order to preserve the research value of these precious samples, contamination must be minimized, understood, and documented. In addition the samples must be preserved - as far as possible - from physical and chemical alteration. In 2011 NASA selected the OSIRIS-REx mission, designed to return samples from the primitive asteroid 1999 RQ36 (Bennu). JAXA will sample C-class asteroid 1999 JU3 with the Hayabusa-2 mission. ESA is considering the near-Earth asteroid sample return mission Marco Polo-R. The Decadal Survey listed the first lander in a Mars sample return campaign as its highest priority flagship-class mission, with sample return from the South Pole-Aitken basin and the surface of a comet among additional top priorities. The latest NASA budget proposal includes a mission to capture a 5-10 m asteroid and return it to the vicinity of the Moon as a target for future sampling. Samples, tools, containers, and contamination witness materials from any of these missions carry unique requirements for acquisition and curation. Some of these requirements represent significant advances over methods currently used. New analytical and screening techniques will increase the value of current sample collections. Improved web-based tools will make information on all samples more accessible to researchers and the public. Advanced curation of current and future extraterrestrial samples includes: Contamination Control - inorganic / organic Temperature of preservation - subfreezing / cryogenic Non-destructive preliminary examination - X-ray tomography / XRF mapping / Raman mapping Microscopic samples - handling / sectioning / transport Special samples - unopened lunar cores Informatics - online catalogs / community-based characterization.

  15. Advancing Solar Irradiance Measurement for Climate-Related Studies: Accurate Constraint on Direct Aerosol Radiative Effect (DARE)

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Ji, Q. Jack

    2011-01-01

    Earth's climate is driven primarily by solar radiation. As summarized in various IPCC reports, the global average of radiative forcing for different agents and mechanisms, such as aerosols or CO2 doubling, is in the range of a few W/sq m. However, when solar irradiance is measured by broadband radiometers, such as the fleet of Eppley Precision Solar Pyranometers (PSP) and equivalent instrumentation employed worldwide, the measurement uncertainty is larger than 2% (e.g., WMO specification of pyranometer, 2008). Thus, out of the approx. 184 W/sq m (approx.263 W/sq m if cloud-free) surface solar insolation (Trenberth et al. 2009), the measurement uncertainty is greater than +/-3.6 W/sq m, overwhelming the climate change signals. To discern these signals, less than a 1 % measurement uncertainty is required and is currently achievable only by means of a newly developed methodology employing a modified PSP-like pyranometer and an updated calibration equation to account for its thermal effects (li and Tsay, 2010). In this talk, we will show that some auxiliary measurements, such as those from a collocated pyrgeometer or air temperature sensors, can help correct historical datasets. Additionally, we will also demonstrate that a pyrheliometer is not free of the thermal effect; therefore, comparing to a high cost yet still not thermal-effect-free "direct + diffuse" approach in measuring surface solar irradiance, our new method is more economical, and more likely to be suitable for correcting a wide variety of historical datasets. Modeling simulations will be presented that a corrected solar irradiance measurement has a significant impact on aerosol forcing, and thus plays an important role in climate studies.

  16. Mass mortality and extraterrestrial impacts

    NASA Technical Reports Server (NTRS)

    Jansa, L. F.; Gradstein, F. M.; Pierre-Aubry, M.

    1988-01-01

    The discovery of iridium enrichment at the Cretaceous/Tertiary boundary resulted in formulation of hypothesis of a cometary or asteroid impact as the cause of the biological extinctions at this boundary. Subsequent discoveries of geochemical anomalies at major stratigraphic boundaries like the Precambrian/Cambrian, Permian/Triassic, Middle/Late Jurassic, resulted in the application of similar extraterrestrial impact theories to explain biological changes at these boundaries. Until recently the major physical evidence, as is the location of the impact crater site, to test the impact induced biological extinction was lacking. The diameter of such a crater would be in the range of 60 to 100 km. The recent discovery of the first impact crater in the ocean provide the first opportunity to test the above theory. The crater, named Montagnais and located on the outer shelf off Nova Scotia, Canada, has a minimum diameter of 42 km, with some evidence to a diameter of more than 60 km. At the Montagnais impact site, micropaleontological analysis of the uppermost 80 m of the fall-back breccia represented by a mixture of pre-impact sediments and basement rocks which fills the crater and of the basal 50 m of post-impact marine sediments which overly the impact deposits, revealed presence of diversified foraminiferal and nannoplankton assemblages. The sediments which are intercalated within the uppermost part of the fall-back breccia, had to be deposited before the meteorite impact. The post-impact deposits were laid down almost immediately after the impact as also supported by the micropaleontological data. In conclusion, micropaleontological studies of sediments from the first submarine impact crater site identified in the ocean did not reveal any mass extinction or significant biological changes at the impact site or in the proximal deep ocean basin.

  17. Corroboration for the influence of a component of solar irradiance on subsurface radon signals

    NASA Astrophysics Data System (ADS)

    Steinitz, G.; Piatibratova, O.; Kotlarsky, P.; Sturrock, P.; Maritn, C.

    2012-04-01

    Rn-222 occurs at highly varying levels as a trace component in subsurface air (geogas). This high variability is traced by alpha and gamma activity due to the decay of radon and its progeny. Nuclear radiation from radon in geogas and in experiments using air+radon within a confined volume exhibits systematic temporal variations. These variations are composed of periodic and non-periodic signals spanning several orders of magnitude in time - from annual to daily and sub-daily durations. Analysis of extensive data sets from three key sites 200 km apart in the arid desert of southern Israel [1-3] and from a 5-year experiment using alpha and gamma detectors [4] demonstrate that the periodic variations, observed to a depth of >100 meters, are related to an above surface driver probably due to a component of solar irradiance. Insight was also derived from the long term variations in the geological and the experimental time series [5], indicated by the occurrence of multi-year variations, and clear semiannual and ternary annual signals which are in addition to the annual periodicity. New confirmations are based on recognizing further cyclic phenomena, some of which are not linked with Earth related periodicities. A likehood analysis of the alpha and gamma time series in a long-term experiment is performed. A Combined Power Statistic formed from the gamma, alpha-H and alpha-L sensors inside the experimental tank shows that the time series of the gamma radiation contains an annual periodicity as well as a clear semi-annual and possibly a ternary-annual periodicity. The same analysis also resolves additional periodicities in the frequency range of 10-15 yr-1 in the gamma time series which are indicative of a relationship to rotation of the sun around its axis [6]. Observation of solar periodicities in the temporal pattern of the nuclear radiation of radon is a significant independent substantiation for the notion of the influence of a component in solar irradiance. An independent confirmation of the solar effect in the experimental data is obtained by observing day time and night time patterns. "Specgrams" of the power as a function of frequency and hour of day show that the peak of the annual periodicity occurs at daytime while the semi-annual and solar periodicities are seen to be prominent at night. This is interpreted to indicate a differentiation in the nuclear radiation from radon as a function of rotation of Earth. - i.e. when Earth faces the sun and when the sun is completely obstructed. This feature is also demonstrated using Continuous Wavelet Transform (CWT) analysis on separate time series composed of day-time and night-time measurements. Applying the CWT analysis yields different frequency-time variation patterns for day-time and night-time measurements in the experimental data. This confirms the utilization of the CWT analysis for detecting the phenomena. Using the CWT analysis tool the day- and night-time difference in radon time series is also detected at subsurface geological sites from Israel, Tenerife and Italy. These sites are from different geological and geophysical scenarios, different elevations and span depths from several meters to around 1000m below the surface. New multi disciplinary prospects for the research are indicated in terms of a) the radioactive behavior of radon in above surface and subsurface air, b) an above surface geophysical driver for this behavior and, c) the influence of a component of solar irradiation. 1. Steinitz, G., O. Piatibratova, and S. M. Barbosa, 2007. Radon daily signals in the Elat Granite, southern Arava, Israel, J. Geophys. Res., 112, B10211, doi:10.1029/2006JB004817. 2. Steinitz, G., Piatibratova, O., 2010a. Radon signals in the Gavnunim intrusion, Makhtesh Ramon, Israel. Geophys. J. Int. 180, 651-665. 3. Steinitz, G. and Piatibratova, O., 2010. Radon signals at the Roded site, Southern Israel, Solid Earth, 1, 99-109, doi:10.5194/se-1-99-2010. 4. Steinitz, G., Piatibratova, O., Kotlarsky, P., 2011. Possible effect of solar tides on radon signals. Journal of

  18. Diffusion length variation in 0.5- and 3-MeV-proton-irradiated, heteroepitaxial indium phosphide solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Weinberg, Irving; Flood, Dennis J.

    1993-01-01

    Indium phosphide (InP) solar cells are more radiation resistant than gallium arsenide (GaAs) and silicon (Si) solar cells, and their growth by heteroepitaxy offers additional advantages leading to the development of light weight, mechanically strong, and cost-effective cells. Changes in heteroepitaxial InP cell efficiency under 0.5- and 3-MeV proton irradiations have been explained by the variation in the minority-carrier diffusion length. The base diffusion length versus proton fluence was calculated by simulating the cell performance. The diffusion length damage coefficient, K(sub L), was also plotted as a function of proton fluence.

  19. An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis

    E-print Network

    Claeys, Philippe

    An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis Todd A. Surovella an impact by an extraterrestrial body, an event that had devastating ecological consequences for humans any results of the Firestone et al. study and find no support for Younger Dryas extraterrestrial

  20. Absence of extraterrestrial 3 He in PermianTriassic

    E-print Network

    Mukhopadhyay, Sujoy

    Absence of extraterrestrial 3 He in Permian­Triassic age sedimentary rocks K.A. Farley a,*, P. Ward the Permian­Triassic boundary at Opal Creek, Canada, to determine whether high extraterrestrial helium concentrations are associated with a possible extinction- inducing impact event at this time. No extraterrestrial

  1. A Center for Extraterrestrial Engineering and Construction (CETEC)

    Microsoft Academic Search

    Gerald G. Leigh

    1992-01-01

    A group of knowledgeable scientists and engineers in New Mexico has recognized the need for such a testing capability and has proposed a project to evelop an extraterrestrial surface simulation facility. A group of universities, national laboratories, and private industrial firms is proposing to establish a Center for Extraterrestrial Engineering and Construction (CETEC) and to develop large extraterrestrial surface simulation

  2. Spiritualists, Aliens and UFOs: Extraterrestrials as spirit guides

    Microsoft Academic Search

    Jennifer E. Porter

    1996-01-01

    One of the most striking innovations within contemporary North American Spiritualism is the adoption of extraterrestrials as spirit guides by some contemporary Spiritualists. It is here that the New Age fascination with extraterrestrials and UFOs has taken on a uniquely Spiritualist form. Extraterrestrials have come to represent for many Spiritualists the successful achievement of the ultimate Spiritualist goal: the union

  3. Direct-to-diffuse UV Solar Irradiance Ratio for a UV rotating Shadowband Spectroradiometer and a UV Multi-filter Rotating Shadowband Radiometer

    NASA Astrophysics Data System (ADS)

    Lantz, K.; Kiedron, P.; Petropavlovskikh, I.; Michalsky, J.; Slusser, J.

    2008-12-01

    . Two spectroradiometers reside that measure direct and diffuse UV solar irradiance are located at the Table Mountain Test Facility, 8 km north of Boulder, CO. The UV- Rotating Shadowband Spectrograph (UV-RSS) measures diffuse and direct solar irradiance from 290 - 400 nm. The UV Multi-Filter Rotating Shadowband Radiometer (UV-MFRSR) measures diffuse and direct solar irradiance in seven 2-nm wide bands, i.e. 300, 305, 311, 317, 325, and 368 nm. The purpose of the work is to compare radiative transfer model calculations (TUV) with the results from the UV-Rotating Shadowband Spectroradiometer (UV-RSS) and the UV-MFRSR to estimate direct-to-diffuse solar irradiance ratios (DDR) that are used to evaluate the possibility of retrieving aerosol single scattering albedo (SSA) under a variety of atmospheric conditions: large and small aerosol loading, large and small surface albedo. For the radiative transfer calculations, total ozone measurements are obtained from a collocated Brewer spectrophotometer.

  4. Impact of differences in the solar irradiance spectrum on surface reflectance retrieval with different radiative transfer codes

    NASA Technical Reports Server (NTRS)

    Staenz, K.; Williams, D. J.; Fedosejevs, G.; Teillet, P. M.

    1995-01-01

    Surface reflectance retrieval from imaging spectrometer data as acquired with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has become important for quantitative analysis. In order to calculate surface reflectance from remotely measured radiance, radiative transfer codes such as 5S and MODTRAN2 play an increasing role for removal of scattering and absorption effects of the atmosphere. Accurate knowledge of the exo-atmospheric solar irradiance (E(sub 0)) spectrum at the spectral resolution of the sensor is important for this purpose. The present study investigates the impact of differences in the solar irradiance function, as implemented in a modified version of 5S (M5S), 6S, and MODTRAN2, and as proposed by Green and Gao, on the surface reflectance retrieved from AVIRIS data. Reflectance measured in situ is used as a basis of comparison.

  5. DLTS analysis and modeling of electron and proton irradiated (AlGa)As/GaAs multijunction solar cells

    NASA Astrophysics Data System (ADS)

    Li, Sheng S.

    1987-03-01

    A numerical model has been developed to calculate the displacement defects, the damage constant of minority carrier diffusion length and the degradation of short circuit current (I sub sc), open circuit voltage (V sub oc) and conversion efficiency (eta sub c) in the 1 MeV electron and proton irradiated AlGaAs/GaAs/InGaAs multijunction junction solar cell under normal incidence conditions. The results show good agreement between calculated values and the experimental data of I sub sc, V sub oc and eta sub c. In addition, DLTS analysis of defects in AlGaAs p-n junction solar cells irradiated by 1-MeV electrons has also been carried out. The I-V analysis on several MOCVD-grown Ge/GaAs tunnel junction diodes has also been made in this study.

  6. Searching for extraterrestrial intelligence - The ultimate exploration

    NASA Technical Reports Server (NTRS)

    Black, D.; Tarter, J.; Cuzzi, J. N.; Conners, M.; Clark, T. A.

    1977-01-01

    A survey highlighting the central issues of the SETI program (Search for Extraterrestrial Intelligence), including its rationale, scope, search problems, and goals is presented. Electromagnetic radiation is suggested as the most likely means via which knowledge of extraterrestrial intelligence will be obtained, and the variables governing these signals are discussed, including: signal frequency and polarization, state, possible coordinates, and signal duration. The modern history of SETI and NASA's involvement is briefly reviewed, and the search strategies used by the Jet Propulsion Laboratory and the Ames Research Center are discussed and compared. Some of the potential scientific and cultural impacts of the SETI program are mentioned, noting advancements in technological, biological, and chemical research.

  7. Correlations for damage in diffused-junction InP solar cells induced by electron and proton irradiation

    Microsoft Academic Search

    Masafumi Yamaguchi; Tatsuya Takamoto; Stephen J. Taylor; Robert J. Walters; Geoffrey P. Summers; Dennis J. Flood; Masamichi Ohmori

    1997-01-01

    The damage to diffused-junction n+-p InP solar cells induced by electron and proton irradiations over a wide range of energy from 0.5 to 3 MeV and 0.015 to 20 MeV, respectively, has been examined. The experimental electron and proton damage coefficients have been analyzed in terms of displacement damage dose, which is the product of the particle fluence and the

  8. Comparing irradiance fields derived from Moderate Resolution Imaging Spectroradiometer airborne simulator cirrus cloud retrievals with solar spectral flux radiometer measurements

    Microsoft Academic Search

    K. Sebastian Schmidt; Peter Pilewskie; Steven Platnick; Gala Wind; Ping Yang; Manfred Wendisch

    2007-01-01

    During the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment, the Moderate Resolution Imaging Spectroradiometer (MODIS) airborne simulator (MAS) and the solar spectral flux radiometer (SSFR) operated on the same aircraft, the NASA ER-2. While MAS provided two-dimensional horizontal fields of cloud optical thickness and effective ice particle radius, the SSFR measured spectral irradiance in the

  9. Gene Expression in the Scleractinian Acropora microphthalma Exposed to High Solar Irradiance Reveals Elements of Photoprotection and Coral Bleaching

    PubMed Central

    Starcevic, Antonio; Dunlap, Walter C.; Cullum, John; Shick, J. Malcolm; Hranueli, Daslav; Long, Paul F.

    2010-01-01

    Background The success of tropical reef-building corals depends on the metabolic co-operation between the animal host and the photosynthetic performance of endosymbiotic algae residing within its cells. To examine the molecular response of the coral Acropora microphthalma to high levels of solar irradiance, a cDNA library was constructed by PCR-based suppression subtractive hybridisation (PCR-SSH) from mRNA obtained by transplantation of a colony from a depth of 12.7 m to near-surface solar irradiance, during which the coral became noticeably paler from loss of endosymbionts in sun-exposed tissues. Methodology/Principal Findings A novel approach to sequence annotation of the cDNA library gave genetic evidence for a hypothetical biosynthetic pathway branching from the shikimic acid pathway that leads to the formation of 4-deoxygadusol. This metabolite is a potent antioxidant and expected precursor of the UV-protective mycosporine-like amino acids (MAAs), which serve as sunscreens in coral phototrophic symbiosis. Empirical PCR based evidence further upholds the contention that the biosynthesis of these MAA sunscreens is a ‘shared metabolic adaptation’ between the symbiotic partners. Additionally, gene expression induced by enhanced solar irradiance reveals a cellular mechanism of light-induced coral bleaching that invokes a Ca2+-binding synaptotagmin-like regulator of SNARE protein assembly of phagosomal exocytosis, whereby algal partners are lost from the symbiosis. Conclusions/Significance Bioinformatics analyses of DNA sequences obtained by differential gene expression of a coral exposed to high solar irradiance has revealed the identification of putative genes encoding key steps of the MAA biosynthetic pathway. Revealed also by this treatment are genes that implicate exocytosis as a cellular process contributing to a breakdown in the metabolically essential partnership between the coral host and endosymbiotic algae, which manifests as coral bleaching. PMID:21103042

  10. Flight degradation data of GaAs-on-Si solar cells mounted on highly irradiated ETS-VI [satellite

    Microsoft Academic Search

    M. Imaizumi; O. Anzawa; S. Matsuda; M. Yamaguchi; T. Ohara

    2000-01-01

    Flight data of GaAs space solar cells fabricated on Si substrates (GaAs\\/Si) are analyzed by comparing with the data of GaAs cells on GaAs substrates (GaAs\\/GaAs). The initial performance of the GaAs\\/Si cells is comparable to the GaAs\\/GaAs cells. Both types of cells are mounted on the body of the ETS-VI satellite, which has been highly irradiated due to its

  11. Century-long monitoring of solar irradiance and Earth's albedo using a stable scattering target in space

    NASA Astrophysics Data System (ADS)

    Judge, Philip G.; Egeland, Ricky

    2015-03-01

    An inert sphere of a few metres diameter, placed in a special stable geosynchronous orbit in perpetuo, can be used for a variety of scientific experiments. Ground-based observations of such a sphere, `GeoSphere', can resolve very difficult problems in measuring the long-term solar irradiance. GeoSphere measurements will also help us understand the evolution of Earth's albedo and climate over at least the next century.

  12. Bifunctional TiO2 Catalysts for Efficient Cr(VI) Photoreduction Under Solar Light Irradiation Without Addition of Acids

    NASA Astrophysics Data System (ADS)

    Shi, Fu-cheng; Wang, Wen-dong; Huang, Wei-xin

    2012-04-01

    Bifunctional TiO2 photocatalysts co-doped with nitrogen and sulfur were prepared by the controlled thermal decomposition of ammonium titanyl sulfate precursor. They have both photocatalytic activity and Brønsted acidity, and thus are active in the photoreduction of Cr(VI) under solar light irradiation without the addition of acids. The activity is superior to that of Degussa P25 in the acidified suspension at the same pH adjusted by H2SO4.

  13. Satellite-Derived Surface Radiation Budget over the African Continent. Part I: Estimation of Downward Solar Irradiance and Albedo

    Microsoft Academic Search

    Mamoudou B. Ba; Robert Frouin; Sharon E. Nicholson; Gérard Dedieu

    2001-01-01

    Downward surface solar irradiance and albedo of the African continent are estimated from Meteosat B2 data at 30-km spatial resolution. The algorithm, based on Dedieu et al.'s approach, is verified against other satellite estimates and ground-based measurements. In the computations, the International Satellite Cloud Climatology Project's (ISCCP) radiometric calibration is adjusted using the Libyan desert as a reference target of

  14. Gene Expression in the Scleractinian Acropora microphthalma Exposed to High Solar Irradiance Reveals Elements of Photoprotection and Coral Bleaching

    Microsoft Academic Search

    Antonio Starcevic; Walter C. Dunlap; John Cullum; J. Malcolm Shick; Daslav Hranueli; Paul F. Long

    2010-01-01

    BackgroundThe success of tropical reef-building corals depends on the metabolic co-operation between the animal host and the photosynthetic performance of endosymbiotic algae residing within its cells. To examine the molecular response of the coral Acropora microphthalma to high levels of solar irradiance, a cDNA library was constructed by PCR-based suppression subtractive hybridisation (PCR-SSH) from mRNA obtained by transplantation of a

  15. DLTS analysis and modeling of electron and proton irradiated (AlGa)As\\/GaAs multijunction solar cells

    Microsoft Academic Search

    Sheng S. Li

    1987-01-01

    A numerical model has been developed to calculate the displacement defects, the damage constant of minority carrier diffusion length and the degradation of short circuit current (I sub sc), open circuit voltage (V sub oc) and conversion efficiency (eta sub c) in the 1 MeV electron and proton irradiated AlGaAs\\/GaAs\\/InGaAs multijunction junction solar cell under normal incidence conditions. The results

  16. Spatial resolution and nature of defects produced by low-energy proton irradiation of GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Kachare, R.; Anspaugh, B. E.

    1986-01-01

    AlGaAs/GaAs solar cells with about 0.5-micron-thick Al(0.85)Ga(0.15)As window layers were irradiated using isotropic and normal incidence protons having energies between 50 and 500 keV with fluences up to 1 x 10 to the 12th protons/sq cm. Although the projected range for these protons varies from 0 to more than 4.5 microns, the recombination losses due to the irradiation-induced defects were observed to be maximum in the vicinity of the AlGaAs/GaAs interface and the space-charge region irrespective of the proton energy. This was found by analyzing spectral response measurements. The results are explained by using a model in which the interaction of as-grown dislocations with irradiation-induced point defects is considered.

  17. Using CAD software to simulate PV energy yield - The case of product integrated photovoltaic operated under indoor solar irradiation

    SciTech Connect

    Reich, N.H.; van Sark, W.G.J.H.M.; Turkenburg, W.C. [Dept. of Science, Technology and Society, Copernicus Institute for Sustainable Development and Innovation, Utrecht University, Heidelberglaan 2, 3584 CS, Utrecht (Netherlands); Sinke, W.C. [Dept. of Science, Technology and Society, Copernicus Institute for Sustainable Development and Innovation, Utrecht University, Heidelberglaan 2, 3584 CS, Utrecht (Netherlands); Energy Research Centre of the Netherlands (ECN), Petten (Netherlands)

    2010-08-15

    In this paper, we show that photovoltaic (PV) energy yields can be simulated using standard rendering and ray-tracing features of Computer Aided Design (CAD) software. To this end, three-dimensional (3-D) sceneries are ray-traced in CAD. The PV power output is then modeled by translating irradiance intensity data of rendered images back into numerical data. To ensure accurate results, the solar irradiation data used as input is compared to numerical data obtained from rendered images, showing excellent agreement. As expected, also ray-tracing precision in the CAD software proves to be very high. To demonstrate PV energy yield simulations using this innovative concept, solar radiation time course data of a few days was modeled in 3-D to simulate distributions of irradiance incident on flat, single- and double-bend shapes and a PV powered computer mouse located on a window sill. Comparisons of measured to simulated PV output of the mouse show that also in practice, simulation accuracies can be very high. Theoretically, this concept has great potential, as it can be adapted to suit a wide range of solar energy applications, such as sun-tracking and concentrator systems, Building Integrated PV (BIPV) or Product Integrated PV (PIPV). However, graphical user interfaces of 'CAD-PV' software tools are not yet available. (author)

  18. A model for light distribution and average solar irradiance inside outdoor tubular photobioreactors for the microalgal mass culture

    SciTech Connect

    Fernandez, F.G.A.; Camacho, F.G.; Perez, J.A.S.; Sevilla, J.M.F.; Grima, E.M. [Univ. of Almeria (Spain). Dept. of Chemical Engineering] [Univ. of Almeria (Spain). Dept. of Chemical Engineering

    1997-09-05

    A mathematical model to estimate the solar irradiance profile and average light intensity inside a tubular photobioreactor under outdoor conditions is proposed, requiring only geographic, geometric, and solar position parameters. First, the length of the path into the culture traveled by any direct or disperse ray of light was calculated as the function of three variables: day of year, solar hour, and geographic latitude. Then, the phenomenon of light attenuation by biomass was studied considering Lambert-Beer`s law (only considering absorption) and the monodimensional model of Cornet et al. (1900) (considering absorption and scattering phenomena). Due to the existence of differential wavelength absorption, none of the literature models are useful for explaining light attenuation by the biomass. Therefore, an empirical hyperbolic expression is proposed. The equations to calculate light path length were substituted in the proposed hyperbolic expression, reproducing light intensity data obtained in the center of the loop tubes. The proposed model was also likely to estimate the irradiance accurately at any point inside the culture. Calculation of the local intensity was thus extended to the full culture volume in order to obtain the average irradiance, showing how the higher biomass productivities in a Phaeodactylum tricornutum UTEX 640 outdoor chemostat culture could be maintained by delaying light limitation.

  19. Solar Spectral Irradiance Variability in November/December 2012: Comparison of Observations by Instruments on the International Space Station and Models

    NASA Astrophysics Data System (ADS)

    Thuillier, G.; Schmidtke, G.; Erhardt, C.; Nikutowski, B.; Shapiro, A. I.; Bolduc, C.; Lean, J.; Krivova, N.; Charbonneau, P.; Cessateur, G.; Haberreiter, M.; Melo, S.; Delouille, V.; Mampaey, B.; Yeo, K. L.; Schmutz, W.

    2014-12-01

    Onboard the International Space Station (ISS), two instruments are observing the solar spectral irradiance (SSI) at wavelengths from 16 to 2900 nm. Although the ISS platform orientation generally precludes pointing at the Sun more than 10 - 14 days per month, in November/December 2012 a continuous period of measurements was obtained by implementing an ISS `bridging' maneuver. This enabled observations to be made of the solar spectral irradiance (SSI) during a complete solar rotation. We present these measurements, which quantify the impact of active regions on SSI, and compare them with data simultaneously gathered from other platforms, and with models of spectral irradiance variability. Our analysis demonstrates that the instruments onboard the ISS have the capability to measure SSI variations consistent with other instruments in space. A comparison among all available SSI measurements during November-December 2012 in absolute units with reconstructions using solar proxies and observed solar activity features is presented and discussed in terms of accuracy.

  20. Photodegradation of selected polycyclic aromatic hydrocarbons in surface microlayer under direct solar irradiance

    SciTech Connect

    Liu, K.; Dickhut, R.M. [College of William and Mary, Gloucester Point, VA (United States)

    1995-12-31

    Photodegradation kinetics of selected polycyclic aromatic hydrocarbons (PAHs) in the presence of various particle and dissolved phases were examined in surface microlayer (SM) and surface water under direct solar irradiance during different seasons. Halflives of PAHs during different seasons in the various media were determined. The results showed shorter halflives measured at the surface for PAHs in the SM media than in surface water. Submergence depth also significantly affected rate constants, and halflives for PAH compounds were 1.4 to 5 times shorter at the surface than at 14cm depth below the surface. In bulk SM media, the annual average halflives varied from 1.3 to 43 hours (midday) with different PAH compounds, and in filtered SM from 1.8 to 56.9 hours (midday). The effects of particles and DOC on the photodegradation of PAHs were also inspected. The results showed particulates and DOC both enhanced or decreased the photodegradation rate constants for selected PAHs. Overall, PAH photoreactivity is related to the compound`s maximum net atomic charge (MNAC) on the most reactive carbon center of a specific PAH molecule.

  1. Response of atmospheric ground level temperatures to changes in the total solar irradiance

    E-print Network

    Erlykin, Anatoly

    2015-01-01

    The attribution of part of global warming to changes in the total solar irradiance (TSI) is an important topic which is not, yet, fully understood. Here, we examine the TSI induced temperature (T) changes on a variety of time scales, from one day to centuries and beyond, using a variety of assumptions. Also considered is the latitude variation of the T-TSI correlations, where it appears that over most of the globe there is a small increase in the sensitivity of temperature to TSI in time. It is found that the mean global sensitivity (alpha)measured in K(Wm-2)-1 varies from about 0.003 for 1 day, via 0.05 for 11-years to about 0.2 for decades to centuries. We conclude that mean global temperature changes related to TSI are not significant from 1975 onwards. Before 1975, when anthropogenic gases were less important, many of the temperature changes can be attributed to TSI variations. Over much longer periods of time, from Kyear to Myear, the TSI changes are more efficient still, the sensitivity alpha increasing...

  2. Air pollution is pushing wind speed into a regulator of surface solar irradiance in China

    NASA Astrophysics Data System (ADS)

    Wang, Y. W.; Yang, Y. H.; Zhou, X. Y.; Zhao, N.; Zhang, J. H.

    2014-05-01

    Analysis in 27 cities across China shows that surface solar irradiance (SSI) and wind speed track similar decadal trends in 1961-2011, suggesting wind speed as a possible regulator of SSI. This assumption is further confirmed by the continuously widening gap in annually averaged daily SSI between windy and windless clear-sky days with worsening air pollution. Wider gaps are noted for more polluted cities and seasons. The gap in SSI between windy and windless conditions could therefore serve as a good indicator for air quality. The regulatory effect of wind speed on SSI starts to be important when air pollution index exceeds the boundary of 125. A plausible mechanism of wind speed regulating SSI through interactions with aerosols is proposed. There are two cut-off points of 2.5 m s-1 and 3.5 m s-1 wind speeds. Winds <2.5 m s-1 noticeably disperse air pollutants and thereby enhance SSI. Above the 2.5 m s-1 threshold, air pollution and SSI become largely insensitive to changing wind speeds. Winds in excess of 3.5 m s-1 could enhance aerosol concentration probably by inducing dust-storms, which in turn attenuate SSI.

  3. Early irradiation of matter in the solar system - Magnesium /proton, neutron/ scheme

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Dziczkaniec, M.

    1976-01-01

    The occurrence of positive and negative Mg-26 anomalies in inclusions of the Allende meteorite is explained in terms of proton bombardment of a gas of solar composition. A significant fraction of Mg-26 in the irradiated gas is stored temporarily in the form of radioactive Al-26 by the reaction Mg-26(p, n)Al-26. Proton fluxes of 10 to the 17th power to 10 to the 19th power protons per square centimeter per year at 1 million electron volts are inferred. Aluminum-rich materials condensing from the gas phase have positive Mg-26 anomalies, whereas magnesium-rich materials have negative Mg-26 anomalies. The proton flux required to account for the observed magnesium anomalies is used to investigate possible isotopic anomalies in the elements from oxygen to argon. Detectable isotopic anomalies are predicted only for neon. The anomalous neon is virtually pure Ne-22 from Na-22 decay. The predicted amount of anomalous Ne-22 is about 10 to the -8th power cubic centimeter (at standard temperature and pressure) per milligram of sodium.

  4. SOLAR AND METEOROLOGICAL SURFACE OBSERVATION NETWORK (SAMSON) FOR NC, VA

    EPA Science Inventory

    Solar and Meteorological Surface Observational Network (SAMSON) v1.0 data for 6 NWS stations in North Carolina and 4 in Virginia. Hourly solar elements are: extraterrestrial horizontal and extraterrestrial direct normal radiation; global, diffuse, and direct normal radiation. Met...

  5. Simple Solar Spectral Model for Direct and Diffuse Irradiance on Horizontal and Tilted Planes at the Earth's Surface for Cloudless Atmospheres

    Microsoft Academic Search

    Richard E. Bird; Carol Riordan

    1986-01-01

    In a previous work, we described a simple model for calculating direct normal and diffuse horizontal spectral solar irradiance for cloudless sky conditions. In this paper, we present a new simple model (SPCTRAL2) that incorporates improvements to the simple model approach and an algorithm for calculating spectral irradiance on tilted surfaces. The model was developed using comparisons with rigorous radiative

  6. Optimization design of hybrid Fresnel-based concentrator for generating uniformity irradiance with the broad solar spectrum

    NASA Astrophysics Data System (ADS)

    Zhuang, Zhenfeng; Yu, Feihong

    2014-08-01

    This paper presents a novel hybrid Fresnel-based concentrator with improved uniformity irradiance distribution on the solar cell without using secondary optical element (SOE) in the concentrator photovoltaic (CPV) system to overcome the Fresnel loss and to increase the solar cell conversion efficiency. The designed hybrid Fresnel-based concentrator is composed of two parts, the inner part and the outer part. The inner part is the conventional Fresnel lens, while the outer part is double total internal reflection (DTIR) lens. According to the simple geometrical relation, the profile of the proposed hybrid Fresnel-based concentrator is calculated as an initial design profile. To obtain good irradiance uniformity on the solar cell, optimal prism displacements are optimized by using a simplex algorithm for collimated incident sunlight based on different prism focus on different position principles. In addition, a Monte-Carlo ray-tracing simulation approach is utilized to verify the optical performance for the hybrid Fresnel-based concentrator. Results indicate that the hybrid Fresnel-based concentrator designed using this method can achieve spatial non-uniformity less than 16.2%, f-number less than 0.59 (focal length to entry aperture diameter ratio), geometrical concentrator ratio 1759.8×, and acceptance angle ±0.23°. Compared to the conventional Fresnel-based lens and the traditional hybrid Fresnel-based lens, the optimized concentrator yields a significant improvement in irradiance uniformity on the solar cell with a wide solar spectrum range. It also has good tolerance to the incident sunlight.

  7. A Short Duration of the Cretaceous-Tertiary Boundary Event: Evidence from Extraterrestrial Helium3

    Microsoft Academic Search

    S. Mukhopadhyay; K. A. Farley; A. Montanari

    2001-01-01

    Analyses of marine carbonates through the interval 63.9 to 65.4 million years ago indicate a near-constant flux of extraterrestrial helium-3, a tracer of the accretion rate of interplanetary dust to Earth. This observation indicates that the bolide associated with the Cretaceous-Tertiary (K-T) extinction event was not accompanied by enhanced solar system dustiness and so could not have been a member

  8. A new empirical approach in the Search for Extraterrestrial Intelligence: Astrobiological nonlocality at the cosmological level

    Microsoft Academic Search

    Fred H. Thaheld

    2006-01-01

    Over a period of several decades a concerted effort has been made to\\u000adetermine whether intelligent life exists outside of our solar system, known as\\u000athe Search for Extraterrestrial Intelligence or SETI. This has been based\\u000aprimarily upon attempting to intercept possible radio transmissions at\\u000adifferent frequencies with arrays of radio telescopes. In addition,\\u000aastrophysical observations have also been undertaken

  9. Search for Extraterrestrial Intelligence at 22 GHz with the Very Large Array

    Microsoft Academic Search

    Toshimichi Shirai; Tomoaki Oyama; Hiroshi Imai; Shinsuke Abe

    2004-01-01

    We have conducted a direct Search for Extraterrestrial Intelligence at the Water Maser frequency, 22.235 GHz, using the Very Large Array. The targets were 13 solar-type stars that were known to host exoplanetary systems. In all cases, the RMS limits of the flux density, 20 mJy (5sigma), were sufficient to rule out any omnidirectional transmitters of the same power as

  10. Isotopic, Chemical and Mineralogical Investigation's of Extraterrestrial Materials

    NASA Technical Reports Server (NTRS)

    Lugmair, G. W.

    2003-01-01

    During the grant period we have concentrated on the following main topics: 1. Enstatite meteorites and original heterogeneity of Mn-53 distribution in the solar nebula. We have completed our studies of the enstatite chondrites. 2. Processes of planetary differentiation. We have completed our study of silicate clasts from the mesosiderite Vaca Muerta and found that the global Mn/Cr fractionation event that established mantle source reservoirs on the parent body of the Vaca Muerta silicate clasts occurred approx. 2 Ma after a similar event on the howardite-eucrite-diogenite (HED) parent body. 3. Carbonaceous chondrites. Much effort has been devoted during the last three years to the investigation of this important class of meteorites. 4. Early solar system timescales. Based on the studies of the Mn-53 - Cr-53 isotope system in various meteorites and using results obtained with other isotope chronometers we constructed an absolute time-scale for events in the early solar system. 5.Unusual meteorites. We have studied the anomalous pallasite Eagle Station. 6. The chromium isotopic composition as a tracer for extraterrestrial material on Earth. Based on the observed difference in the Cr-53/Cr-52 ratios between Earth and the other solar system objects we developed a method for detecting cosmic materials on Earth using the Cr-53/Cr-52 ratio as a tracer.

  11. The Future, Extraterrestrial Space Humanization and Sociology.

    ERIC Educational Resources Information Center

    MacDaniel, William E.

    This paper suggests that sociologists should become actively involved with the study of the future as a means for revitalizing the profession of sociology. One aspect of the future that may be most exciting and challenging is the development of human society and culture in extraterrestrial human communities. A unique combination of technological…

  12. SETI: Search for ExtraTerrestrial Intelligence

    E-print Network

    Walter, Frederick M.

    SETI: Search for ExtraTerrestrial Intelligence I know perfectly well that at this moment the whole, The Madwoman of Chaillot #12;Search Strategies Suppose you find a civilization. You want to communicate. How? #12;Options Passive SETI: Listen Active SETI: Transmit #12;Search Strategies There are two issues: A

  13. The Search for Extraterrestrial Intelligence (SETI)

    E-print Network

    Shirley, Yancy

    #12;The Search for Extraterrestrial Intelligence (SETI) Our goals for learning · What is the Drake Estimate: flife ~ 0.5 - 1 #12;NHP × flife × fciv × fnow How many planets with life develop intelligence planets have intelligent life now? Major extinction events have occurred in the past #12;NHP × flife

  14. The Search for ExtraTerrestrial Intelligence

    Microsoft Academic Search

    J. Tarter

    1998-01-01

    Aliens abound on the movie screens, but in reality we are still trying to find out if we share our universe with other sentient creatures. Intelligence is very difficult to define, and impossible to directly detect over interstellar distances. Therefore, SETI, the search for extraterrestrial intelligence, is actually an attempt to detect evidence of another distant technology. If we find

  15. NASA contemplates radio Search for Extraterrestrial Intelligence

    Microsoft Academic Search

    R. Sheaffer

    1976-01-01

    The paper examines the Search for Extra-terrestrial Intelligence (SETI), with emphasis on the nature of the SETI advisory panel, the Project Cyclops (a giant array of radio telescopes whose performance would imitate that of a single radio dish up to 5 km in diameter) the possibility of an orbiting SETI system assembled by Space Shuttle, and the possibility of a

  16. SETI [Search for ExtraTerrestrial Intelligence

    Microsoft Academic Search

    B. M. Oliver

    1994-01-01

    Some critics of the Search for Extra-Terrestrial Intelligence (SETI) like to bolster their arguments with what they call the Fermi Paradox. Legend has it that one day at Los Alamos, shortly after the Alamogordo test (when the first atomic bomb was exploded in the desert about 50 miles northwest of this town on July 16, 1945), Enrico Fermi abruptly broke

  17. Strategy for the search for extraterrestrial intelligence

    Microsoft Academic Search

    N. S. Kardashev

    1979-01-01

    The problem of detection and investigation of extraterrestrial intelligence is exceptionally important for mankind from a practical standpoint, for its culture and philosophy. Its importance can even be compared to the importance of the main problems confronting our civilization at the present time, since the information obtained as a result of the discovery of intelligence in the Universe will probably

  18. HUMAN UTILIZATION OF SUBSURFACE EXTRATERRESTRIAL ENVIRONMENTS

    Microsoft Academic Search

    P. J. Boston; R. D. Frederick; S. M. Welch; J. Werker; T. R. Meyer; B. Sprungman

    Caves have been used in the ancient past as shelter or habitat by many organisms (including humans). Since antiquity, humans have explored caves for the minerals they contain and sometimes for ceremonial purposes. Over the past century, caves have become the target of increasing exploration, scientific research, and recreation. The use of caves on extraterrestrial bodies for human habitation has

  19. SAS Honors Seminar 259: Extraterrestrial Life

    E-print Network

    Baker, Andrew J.

    SAS Honors Seminar 259: Extraterrestrial Life 12/1/2008 #12; GBT remote observing tomorrow office (if I'm out briefly, a note on the door will indicate my whereabouts). Also: observing tomorrow at least three people). Each group should discuss (in person or by email) the various terms in the original

  20. Conway Morris: Extraterrestrials: Aliens like us?

    Microsoft Academic Search

    Simon Conway Morris

    2005-01-01

    So what are they going to be like, those long-expected extraterrestrials? Hideous hydrocarbon arachnoids, waving laser cannons as they chase screaming humans, repulsively surveying the scene through empathy-free compound eyes? Or maybe laughing bipeds, chatting away, holding a glass of wine, a bit like us?

  1. Isotopic and structural signature of experimentally irradiated organic matter

    NASA Astrophysics Data System (ADS)

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe

    2014-10-01

    The effects of electron irradiation on the structure and the D/H signature of a synthetic analogue of extraterrestrial insoluble organic matter (IOM) were studied. Polyethylene terephthalate (PET) was chosen because it contains both aliphatic and aromatic functional groups. A 900 nm-thick film was irradiated with electrons within the energy range 4-300 keV, for different run durations. Temperature influence was also tested. Irradiated residues were structurally and isotopically characterized by infrared spectroscopy (IR), electronic paramagnetic resonance (EPR), and Secondary Ion Mass Spectrometry (SIMS). With increasing energy deposition, spectroscopic results indicate (i) a gradual amorphization with chain scissions, (ii) an increase of CH2/CH3 and (iii) the formation of quinones. The EPR study shows that mono- and biradicals (organic species with one or several unpaired valence electrons) are also formed during irradiation. As these structural modifications occur, the ?D (initially at -33‰ relative to SMOW) decreases first during a transient step and then stabilizes at ?+300‰. There is a strong correlation between the changes recorded by the different methods and the electron dose. Deposited energy appears to be the key parameter to induce these modifications. In this respect a low-energy electron irradiation causes more damages than high energy ones. Based on our data and considering the current solar electron flux, the irradiation at moderate energy (1-10 keV) can produce significant D-enrichments of the IOM in a timescale compatible with the evolution of a typical protoplanetary disk.

  2. Lanai high-density irradiance sensor network for characterizing solar resource variability of MW-scale PV system.

    SciTech Connect

    Stein, Joshua S.; Johnson, Lars (SunPower Corporation, Richmond, CA); Ellis, Abraham; Kuszmaul, Scott S.

    2012-01-01

    Sandia National Laboratories (Sandia) and SunPower Corporation (SunPower) have completed design and deployment of an autonomous irradiance monitoring system based on wireless mesh communications and a battery operated data acquisition system. The Lanai High-Density Irradiance Sensor Network is comprised of 24 LI-COR{reg_sign} irradiance sensors (silicon pyranometers) polled by 19 RF Radios. The system was implemented with commercially available hardware and custom developed LabVIEW applications. The network of solar irradiance sensors was installed in January 2010 around the periphery and within the 1.2 MW ac La Ola PV plant on the island of Lanai, Hawaii. Data acquired at 1 second intervals is transmitted over wireless links to be time-stamped and recorded on SunPower data servers at the site for later analysis. The intent is to study power and solar resource data sets to correlate the movement of cloud shadows across the PV array and its effect on power output of the PV plant. The irradiance data sets recorded will be used to study the shape, size and velocity of cloud shadows. This data, along with time-correlated PV array output data, will support the development and validation of a PV performance model that can predict the short-term output characteristics (ramp rates) of PV systems of different sizes and designs. This analysis could also be used by the La Ola system operator to predict power ramp events and support the function of the future battery system. This experience could be used to validate short-term output forecasting methodologies.

  3. Extraterrestrial organic matter: a review.

    PubMed

    Irvine, W M

    1998-10-01

    We review the nature of the widespread organic material present in the Milky Way Galaxy and in the Solar System. Attention is given to the links between these environments and between primitive Solar System objects and the early Earth, indicating the preservation of organic material as an interstellar cloud collapsed to form the Solar System and as the Earth accreted such material from asteroids, comets and interplanetary dust particles. In the interstellar medium of the Milky Way Galaxy more than 100 molecular species, the bulk of them organic, have been securely identified, primarily through spectroscopy at the highest radio frequencies. There is considerable evidence for significantly heavier organic molecules, particularly polycyclic aromatics, although precise identification of individual species has not yet been obtained. The so-called diffuse interstellar bands are probably important in this context. The low temperature kinetics in interstellar clouds leads to very large isotopic fractionation, particularly for hydrogen, and this signature is present in organic components preserved in carbonaceous chondritic meteorites. Outer belt asteroids are the probable parent bodies of the carbonaceous chondrites, which may contain as much as 5% organic material, including a rich variety of amino acids, purines, pyrimidines, and other species of potential prebiotic interest. Richer in volatiles and hence less thermally processed are the comets, whose organic matter is abundant and poorly characterized. Cometary volatiles, observed after sublimation into the coma, include many species also present in the interstellar medium. There is evidence that most of the Earth's volatiles may have been supplied by a 'late' bombardment of comets and carbonaceous meteorites, scattered into the inner Solar System following the formation of the giant planets. How much in the way of intact organic molecules of potential prebiotic interest survived delivery to the Earth has become an increasingly debated topic over the last several years. The principal source for such intact organics was probably accretion of interplanetary dust particles of cometary origin. PMID:9742722

  4. An efficient physically based parameterization to derive surface solar irradiance based on satellite atmospheric products

    NASA Astrophysics Data System (ADS)

    Qin, Jun; Tang, Wenjun; Yang, Kun; Lu, Ning; Niu, Xiaolei; Liang, Shunlin

    2015-05-01

    Surface solar irradiance (SSI) is required in a wide range of scientific researches and practical applications. Many parameterization schemes are developed to estimate it using routinely measured meteorological variables, since SSI is directly measured at a very limited number of stations. Even so, meteorological stations are still sparse, especially in remote areas. Remote sensing can be used to map spatiotemporally continuous SSI. Considering the huge amount of satellite data, coarse-resolution SSI has been estimated for reducing the computational burden when the estimation is based on a complex radiative transfer model. On the other hand, many empirical relationships are used to enhance the retrieval efficiency, but the accuracy cannot be guaranteed out of regions where they are locally calibrated. In this study, an efficient physically based parameterization is proposed to balance computational efficiency and retrieval accuracy for SSI estimation. In this parameterization, the transmittances for gases, aerosols, and clouds are all handled in full band form and the multiple reflections between the atmosphere and surface are explicitly taken into account. The newly proposed parameterization is applied to estimate SSI with both Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric and land products as inputs. These retrievals are validated against in situ measurements at the Surface Radiation Budget Network and at the North China Plain on an instantaneous basis, and moreover, they are validated and compared with Global Energy and Water Exchanges-Surface Radiation Budget and International Satellite Cloud Climatology Project-flux data SSI estimates at radiation stations of China Meteorological Administration on a daily mean basis. The estimation results indicates that the newly proposed SSI estimation scheme can effectively retrieve SSI based on MODIS products with mean root-mean-square errors of about 100 Wm- 1 and 35 Wm- 1 on an instantaneous and daily mean basis, respectively.

  5. Wavelength Dependence of Solar Irradiance Enhancement During X-Class Flares and Its Influence on the Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    Huang, Yanshi; Richmond, Arthur D.; Deng, Yue; Chamberlin, Phillip C.; Qian, Liying; Solomon, Stanley C.; Roble, Raymond G.; Xiao, Zuo

    2013-01-01

    The wavelength dependence of solar irradiance enhancement during flare events is one of the important factors in determining how the Thermosphere-Ionosphere (T-I) system responds to flares. To investigate the wavelength dependence of flare enhancement, the Flare Irradiance Spectral Model (FISM) was run for 61 X-class flares. The absolute and the percentage increases of solar irradiance at flare peaks, compared to pre-flare conditions, have clear wavelength dependences. The 0-14 nm irradiance increases much more (approx. 680% on average) than that in the 14-25 nm waveband (approx. 65% on average), except at 24 nm (approx. 220%). The average percentage increases for the 25-105 nm and 122-190 nm wavebands are approx. 120% and approx. 35%, respectively. The influence of 6 different wavebands (0-14 nm, 14-25 nm, 25-105 nm, 105- 120 nm, 121.56 nm, and 122-175 nm) on the thermosphere was examined for the October 28th, 2003 flare (X17-class) event by coupling FISM with the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) under geomagnetically quiet conditions (Kp=1). While the enhancement in the 0-14 nm waveband caused the largest enhancement of the globally integrated solar heating, the impact of solar irradiance enhancement on the thermosphere at 400 km is largest for the 25-105 nm waveband (EUV), which accounts for about 33 K of the total 45 K temperature enhancement, and approx. 7.4% of the total approx. 11.5% neutral density enhancement. The effect of 122-175 nm flare radiation on the thermosphere is rather small. The study also illustrates that the high-altitude thermospheric response to the flare radiation at 0-175 nm is almost a linear combination of the responses to the individual wavebands. The upper thermospheric temperature and density enhancements peaked 3-5 h after the maximum flare radiation.

  6. Wavelength Dependence of Solar Irradiance Enhancement During X-class Flares and Its Influence on the Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    Huang, Yanshi; Richmond, A. D.

    2013-01-01

    The wavelength dependence of solar irradiance enhancement during flare events is one of the important factors in determining how the Thermosphere-Ionosphere (TI) system responds to flares. To investigate the wavelength dependence of flare enhancement, the Flare Irradiance Spectral Model (FISM) was run for 61X-class flares. The absolute and the percentage increases of solar irradiance at flare peaks, compared to pre-flare conditions, have clear wavelength dependences. The 0-4 nm irradiance increases much more ((is) approximately 680 on average) than that in the 14-25 nm waveband ((is) approximately 65 on average), except at 24 nm ( (is) approximately 220). The average percentage increases for the 25-105 nm and 122-190 nm wave bands are approximately 120 and approximately 35, respectively. The influence of 6 different wavebands (0-14 nm, 14-25 nm, 25-105 nm, 105-120 nm, 121.56 nm,and122-175 nm) on the thermosphere was examined for the October 28th, 2003 flare (X17-class) event by coupling FISM with the National Center for Atmospheric Research (NCAR) Thermosphere-Ionosphere-Electrodynamics General Circulation Model(TIE-GCM) under geomagnetically quiet conditions (Kp=1). While the enhancement in the0-14nm waveband caused the largest enhancement of the globally integrated solar heating, the impact of solar irradiance enhancement on the thermosphere at 400 km is largest for the 25-105 nm waveband (EUV), which accounts for about 33 K of the total 45 K temperature enhancement, and approximately 7.4% of the total approximately 11.5% neutral density enhancement. The effect of 122-175 nm flare radiation on the thermosphere is rather small. The study also illustrates that the high-altitude thermospheric response to the flare radiation at 0-175 nm is almost a linear combination of the responses to the individual wavebands. The upper thermospheric temperature and density enhancements peaked 3-5 h after the maximum flare radiation.

  7. Coloration and darkening of methane clathrate and other ices by charged particle irradiation: applications to the outer solar system.

    PubMed

    Thompson, W R; Murray, B G; Khare, B N; Sagan, C

    1987-12-30

    Methane clathrate is expected to be an important carbon-containing ice in the outer solar system. We investigate the effect of electron irradiation by coronal discharge on several simple hydrocarbons enclathrated in or mixed with H2O or H2O+NH3 in simulation of the effects of the solar wind, planetary magnetospheric particles, and cosmic rays on surfaces containing these ices in the outer solar system and interstellar space. H2O+CH4 clathrate, H2O+C2H6, H2O+CH4+NH3, H2O+C2H6+NH3, and H2O+C2H2 are all initially white ices, and all produce yellowish to brownish organic products upon charged particles irradiation. Significant coloration occurs with doses of 10(9) erg cm-2, corresponding to short interplanetary irradiation times. Uranian magnetospheric electrons penetrate to approximately 1 mm depth and deposit this dose in 8, 30, 65, 200, and 500 years into the surfaces of Miranda, Ariel, Umbriel, Titania, and Oberon, respectively. Further irradiation of the laboratory ice surface results in a progressive darkening and a more subdued color. For a conversion efficiency to solids G approximately equal to 1 molecule keV-1, the upper limit for the time for total destruction of CH4 and other simple hydrocarbons in the upper 1 mm is 5 x 10(4) years (Miranda) to 3 x 10(6) years (Oberon). Remote detection of CH4 is possible only when its replenishment rate exceeds the destruction rate at the depth probed by spectroscopy. Reflection spectroscopy or irradiated H2O+CH4 frost is compared with the spectra of several outer solar system objects and to other relevant organic and inorganic materials. Ultraviolet-visible and infrared transmission spectroscopy of the postirradiation residues is presented. Persistence of color and of CH4 ice bands on Triton and Pluto suggests ongoing surface activity and/or atmospheric haze. Over 4 x 10(9) year time scales, > or = 10 m of satellite and cometary surface material is processed by cosmic rays to a radiation-hardened ice-tholin mixture devoid of CH4. Preaccretional chemistry, exogenous materials, and endogenous organic chemistry all contribute to the spectral properties of icy satellites which accreted simple CH(O) molecules. Radiation darkening traces the deposition of mobilized or impact-exposed carbon-bearing volatiles on these satellites. More exhaustive experiments are necessary to work out the detailed relationships between initial composition, exposure age, and color/albedo. PMID:11542127

  8. Solar UV radiation exposure of seamen - Measurements, calibration and model calculations of erythemal irradiance along ship routes

    SciTech Connect

    Feister, Uwe [German Meteorological Service, Meteorological Observatory Lindenberg - Richard-Assmann-Observatory, Am Observatorium 12, 15848 Lindenberg (Germany); Meyer, Gabriele; Kirst, Ulrich [German Social Accident Insurance Institution for Transport and Traffic, Ottenser Hauptstrasse 54, 22765 Hamburg (Germany)

    2013-05-10

    Seamen working on vessels that go along tropical and subtropical routes are at risk to receive high doses of solar erythemal radiation. Due to small solar zenith angles and low ozone values, UV index and erythemal dose are much higher than at mid-and high latitudes. UV index values at tropical and subtropical Oceans can exceed UVI = 20, which is more than double of typical mid-latitude UV index values. Daily erythemal dose can exceed the 30-fold of typical midlatitude winter values. Measurements of erythemal exposure of different body parts on seamen have been performed along 4 routes of merchant vessels. The data base has been extended by two years of continuous solar irradiance measurements taken on the mast top of RV METEOR. Radiative transfer model calculations for clear sky along the ship routes have been performed that use satellite-based input for ozone and aerosols to provide maximum erythemal irradiance and dose. The whole data base is intended to be used to derive individual erythemal exposure of seamen during work-time.

  9. Isotopic anomalies in extraterrestrial grains.

    PubMed

    Ireland, T R

    1996-03-01

    Isotopic compositions are referred to as anomalous if the isotopic ratios measured cannot be related to the terrestrial (solar) composition of a given element. While small effects close to the resolution of mass spectrometric techniques can have ambiguous origins, the discovery of large isotopic anomalies in inclusions and grains from primitive meteorites suggests that material from distinct sites of stellar nucleosynthesis has been preserved. Refractory inclusions, which are predominantly composed of the refractory oxides of Al, Ca, Ti, and Mg, in chondritic meteorites commonly have excesses in the heaviest isotopes of Ca, Ti, and Cr which are inferred to have been produced in a supernova. Refractory inclusions also contain excess 26Mg from short lived 26Al decay. However, despite the isotopic anomalies indicating the preservation of distinct nucleosynthetic sites, refractory inclusions have been processed in the solar system and are not interstellar grains. Carbon (graphite and diamond) and silicon carbide grains from the same meteorites also have large isotopic anomalies but these phases are not stable in the oxidized solar nebula which suggests that they are presolar and formed in the circumstellar atmospheres of carbon-rich stars. Diamond has a characteristic signature enriched in the lightest and heaviest isotopes of Xe, and graphite shows a wide range in C isotopic compositions. SiC commonly has C and N isotopic signatures which are characteristic of H-burning in the C-N-O cycle in low-mass stars. Heavier elements such as Si, Ti, Xe, Ba, and Nd, carry an isotopic signature of the s-process. A minor population of SiC (known as Grains X, ca. 1%) are distinct in having decay products of short lived isotopes 26Al (now 26Mg), 44Ti (now 44Ca), and 49V (now 49Ti), as well as 28Si excesses which are characteristic of supernova nucleosynthesis. The preservation of these isotopic anomalies allows the examination of detailed nucleosynthetic pathways in stars. PMID:11541324

  10. Carbon arc solar simulator

    Microsoft Academic Search

    Robert A. Olson; Jack H. Parker

    1991-01-01

    Measurements of the spatial, spectral, and temporal characteristics of the beam irradiance of a carbon arc solar simulator are reported. Pyroelectric radiometer measurements of total irradiance and spectroradiometer measurements of spectral irradiance are presented. The solar simulator spectral irradiance is compared with the ASTM standard AM 1.5 global solar spectral irradiance over a wavelength region of 300-2500 nm. The suitability

  11. Reconstruction of six decades of daily total solar shortwave irradiation in the Iberian Peninsula using sunshine duration records

    NASA Astrophysics Data System (ADS)

    Román, Roberto; Bilbao, Julia; de Miguel, Argimiro

    2014-12-01

    Total global solar shortwave (G) irradiation and sunshine duration were recorded at nine Spanish stations located in the Iberian Peninsula. G irradiation under cloudless conditions was simulated by means of a radiative transfer model using satellite data as input. A method based on these cloudless simulations and sunshine duration records was developed to reconstruct G series. This model was validated against experimental data, providing a good agreement for cloudless skies (mean bias error of 0.4% and root mean square error of 5.8%). Monthly averages of modelled and measured G irradiation presented a mean bias error of 0.5% and a root mean square error of 3%. Differences between modelled and measured G irradiation were in agreement within the model uncertainties. The reconstruction model was applied to sunshine duration measurements, giving long-term G series at the nine locations. Monthly, seasonal, and annual G anomalies were calculated and analysed. Averaged series (using the nine locations) showed a statistically significant decrease in annual G from 1950 to the mid 1980s (-1.7%dc-1) together with a significant increase from the mid 1980s to 2011 (1.6%dc-1). The effect of uncertainty in the reconstructed series on statistically significant trends was studied.

  12. Validation of Spacecraft Active Cavity Radiometer Total Solar Irradiance (TSI) Long Term Measurement Trends Using Proxy TSI Least Squares Analyses

    NASA Technical Reports Server (NTRS)

    Lee, Robert Benjamin, III; Wilson, Robert S.

    2003-01-01

    Long-term, incoming total solar irradiance (TSI) measurement trends were validated using proxy TSI values, derived from indices of solar magnetic activity. Spacecraft active cavity radiometers (ACR) are being used to measure longterm TSI variability, which may trigger global climate changes. The TSI, typically referred to as the solar constant, was normalized to the mean earth-sun distance. Studies of spacecraft TSI data sets confirmed the existence of a 0.1 %, long-term TSI variability component within a 10-year period. The 0.1% TSI variability component is clearly present in the spacecraft data sets from the 1984-2004 time frame. Typically, three overlapping spacecraft data sets were used to validate long-term TSI variability trends. However, during the years of 1978-1984, 1989-1991, and 1993-1996, three overlapping spacecraft data sets were not available in order to validate TSI trends. The TSI was found to vary with indices of solar magnetic activity associated with recent 10-year sunspot cycles. Proxy TSI values were derived from least squares analyses of the measured TSI variability with the solar indices of 10.7-cm solar fluxes, and with limb-darked sunspot fluxes. The resulting proxy TSI values were compared to the spacecraft ACR measurements of TSI variability to detect ACR instrument degradation, which may be interpreted as TSI variability. Analyses of ACR measurements and TSI proxies are presented primarily for the 1984-2004, Earth Radiation Budget Experiment (ERBE) ACR solar monitor data set. Differences in proxy and spacecraft measurement data sets suggest the existence of another TSI variability component with an amplitude greater than or equal to 0.5 Wm-2 (0.04%), and with a cycle of 20 years or more.

  13. An Instrument-Based Method to Search for Extraterrestrial Interstellar Robotic Probes

    NASA Astrophysics Data System (ADS)

    Stride, S. L.

    Technological advancements have allowed us to build robotic space probes to remotely explore the solar system. Interstellar robotic missions are under serious consideration. Advanced extant extraterrestrial civiliza- tions within the galaxy, if they exist, are very likely exploring with robotic probes as well, some of which may have reached our solar system and taken an interest in life on Earth. Recent technological advances make it possible to conduct a scientific search for evidence of extraterrestrial interstellar robotic probes. Modern solid-state sensing devices and scientific instruments, combined with high-speed computer hardware, can be used in an effort to detect the physical presence of a probe. The SETV (Search for Extraterrestrial Visitation) model is new and an offspring of SETA (artifacts) and SETI. SETV includes the construction of passive autonomous data acquisition platforms using “commercial off-the-shelf” hardware, to collect reliable and unambiguous data on anomalous observational phenomena that may be ETI probes. The SETV hypothesis and experimental methods will be described. The SETV hypothesis can be experimentally tested and attempts to statistically reject a null hypothesis which states that ETI probes do not exist. SETV Pre and Post-detection protocols are necessary and will be examined. SETV is a timely, results-oriented, method worthy of serious consideration in our continuing desire to answer the question “Are we alone?”.

  14. Siderophilic Cyanobacteria for the Development of Extraterrestrial Photoautotrophic Biotechnologies

    NASA Technical Reports Server (NTRS)

    Brown, I. I.; McKay, D. S.

    2010-01-01

    In-situ production of consumables (mainly oxygen) using local resources (In-Situ Resource Utilization-ISRU) will significantly facilitate current plans for human exploration and settlement of the solar system, starting with the Moon. With few exceptions, nearly all technologies developed to date have employed an approach based on inorganic chemistry. None of these technologies include concepts for integrating the ISRU system with a bioregenerative life support system and a food production system. Therefore, a new concept based on the cultivation of cyanobacteria (CB) in semi-closed biogeoreactor, linking ISRU, a biological life support system, and food production, has been proposed. The key feature of the biogeoreactor is to use lithotrophic CB to extract many needed elements such as Fe directly from the dissolved regolith and direct them to any technological loop at an extraterrestrial outpost. Our studies showed that siderophilic (Fe-loving) CB are capable to corrode lunar regolith stimulants because they secrete chelating agents and can tolerate [Fe] up to 1 mM. However, lunar and Martian environments are very hostile (very high UV and gamma-radiation, extreme temperatures, deficit of water). Thus, the selection of CB species with high potential for extraterrestrial biotechnologies that may be utilized in 15 years must be sponsored by NASA as soon as possible. The study of the genomes of candidate CB species and the metagenomes of the terrestrial environments which they inhabit is critical to make this decision. Here we provide preliminary results about peculiarities of the genomes of siderophilic CB revealed by analyzing the genome of siderophilic cyanobacterium JSC-1 and the metagenome of iron depositing hot spring (IDHS) Chocolate Pots (Yellowstone National Park, Wyoming, USA). It has been found that IDHS are richer with ferrous iron than the majority of hot springs around the world. Fe2+ is known to increase the magnitude of oxidative stress in prokaryotes through so called Fenton reaction. It is not surprising therefore that the CB inhabiting IDHS have larger sets of the proteins involved in the maintenance of Fe homeostasis and oxidative stress protection than non-siderophilic CB. This finding combined with our earlier results about the ability of some siderophilic CB to utilize chemical elements released from analogs of lunar and Martian regolith make them the most advanced candidates to be employed in advanced extraterrestrial biotechnologies.

  15. Comparison of the solar spectral ultraviolet irradiance in motor vehicles with windows in an open and closed position.

    PubMed

    Kimlin, M G; Parisi, A V; Carter, B D; Turnbull, D

    2002-08-01

    The solar ultraviolet (UV) spectrum was measured by a spectroradiometer located inside two common Australian vehicles: a family wagon and a four-wheel-drive vehicle. The entrance optics of the spectroradiometer was orientated, in turn, on a horizontal plane, towards the driver and passenger windows and towards the windshield. UV spectra were recorded when the vehicles' windows were in an open and closed position. For a typical Australian family wagon, on a horizontal plane inside the vehicle, closing the windows decreased, the total UV irradiance by a factor of 3.2, whilst in a four-wheel drive the irradiance decreased by a factor of 2.1. In order to reduce the likelihood of developing of UV-related eye and skin disorders, drivers should use appropriate UV protection whilst driving a vehicle with the windows in an open position. Results gained from this research provide new findings on the exposure of humans to UV in a vehicle. PMID:12194009

  16. Analysis of direct solar ultraviolet irradiance measurements in the French Alps. Retrieval of turbidity and ozone column amount.

    PubMed

    Lenoble, Jacqueline; de la Casinière, Alain; Cabot, Thierry

    2004-05-20

    Direct ultraviolet spectral solar irradiance is regularly obtained by the difference between global and diffuse irradiances at the French Alpine station of Briançon; the data of years 2001 and 2002 are analyzed in this paper. Comparison with modeled values is used for cloud screening, and an average UV-A aerosol optical depth is used as an index of turbidity; it is found to be around 0.05 for the clear winter days and around 0.2 in summer. Langley plots are used to verify the instrument calibration; they confirm the expected uncertainty smaller than 5%. The ozone total column amount is estimated with an uncertainty between -3 and Dobson units; comparisons with TOMS (Total Ozone Mapping Spectrometer) overpass values shows agreement within the expected uncertainties of both instruments. PMID:15176202

  17. Comparison of the solar spectral ultraviolet irradiance in motor vehicles with windows in an open and closed position

    NASA Astrophysics Data System (ADS)

    Kimlin, M. G.; Parisi, A. V.; Carter, B. D.; Turnbull, D.

    2002-06-01

    The solar ultraviolet (UV) spectrum was measured by a spectroradiometer located inside two common Australian vehicles: a family wagon and a four-wheel-drive vehicle. The entrance optics of the spectroradiometer was orientated, in turn, on a horizontal plane, towards the driver and passenger windows and towards the windshield. UV spectra were recorded when the vehicles' windows were in an open and closed position. For a typical Australian family wagon, on a horizontal plane inside the vehicle, closing the windows decreased, the total UV irradiance by a factor of 3.2, whilst in a four-wheel drive the irradiance decreased by a factor of 2.1. In order to reduce the likelihood of developing of UV-related eye and skin disorders, drivers should use appropriate UV protection whilst driving a vehicle with the windows in an open position. Results gained from this research provide new findings on the exposure of humans to UV in a vehicle.

  18. Solar UV-B and UV-A irradiance in arid high-mountain regions: Measurements on the island of Tenerife as compared to previous tropical Andes data

    NASA Astrophysics Data System (ADS)

    Piazena, H.; Häder, D.-P.

    2009-12-01

    Spectroradiometric measurements of global and diffuse solar UV-B and UV-A irradiance were performed as a function of solar elevation under clear-sky conditions at altitudes between sea level and the top of the volcano El Teide (3555 m above sea level (asl)) at the arid part of the island of Tenerife (Spain) and compared with irradiance data previously measured in the tropical Chilean Andes. Total optical depths and their components were calculated by using data of direct solar irradiance determined in dependence of the solar elevation angle and of altitude. The Ratio total/Rayleigh optical depth increased with altitude in the short-wavelength UV range and decreased with altitude for long-wavelength UV radiation. Rayleigh scattering contributed dominantly to the attenuation of irradiance for both UV-A and for wavelengths between 308 nm and 319 nm in the total range of altitudes investigated as compared with the contributions of ozone absorption and of aerosol absorption and scattering. The latter effects were more effective for the attenuation of solar irradiance in the spectral range of UV-B for altitudes above about 500-960 m asl as compared with the effect of Rayleigh scattering. Increases of global irradiance with increasing altitude were mainly caused by an increase of the direct component in both spectral ranges. Because of the attenuation of direct solar irradiance during its transmittance through vertically stratified near-surface layers characterized by increased values of the aerosol optical depth, vertical gradients of global irradiance and of its direct component observed at Tenerife in the lower part of the investigated atmospheric layer exceeded in both spectral ranges the gradients determined in the upper part in the case of small solar elevation angles. Similarity with the vertical gradients of global irradiance in the Andes was observed in the case of solar elevation angles above about 40° for both UV-A and UV-B within the upper layer and above about 60° for both layers and for both spectral ranges whereas the gradients observed in both layers at Tenerife covered the gradients derived in the Andes for smaller solar elevation angles.

  19. The Twentieth Century History of the Extraterrestrial Life Debate: Major Themes and Lessons Learned

    NASA Astrophysics Data System (ADS)

    Dick, Steven J.

    In this chapter we provide an overview of the extraterrestrial life debate since 1900, drawing largely on the major histories of the subject during this period, The Biological Universe (Dick 1996), Life on Other Worlds (Dick 1998), and The Living Universe (Dick and Strick 2004), as well as other published work. We outline the major components of the debate, including (1) the role of planetary science, (2) the search for planets beyond the solar system, (3) research on the origins of life, and (4) the Search for Extraterrestrial Intelligence (SETI). We emphasize the discovery of cosmic evolution as the proper context for the debate, reserving the cultural implications of astrobiology for part III of this volume. We conclude with possible lessons learned from this history, especially in the domains of the problematic nature of evidence, inference, and metaphysical preconceptions; the checkered role of theory; and an analysis of how representative general current arguments have fared in the past.

  20. The optical spectroscopy of extraterrestrial molecules

    E-print Network

    T. W. Schmidt; R. G. Sharp

    2005-01-11

    The ongoing quest to identify molecules in the interstellar medium by their electronic spectra in the visible region is reviewed. Identification of molecular absorption is described in the context of the elucidation of the carriers of the unidentified diffuse interstellar bands while molecular emission is discussed with reference to the unidentified Red Rectangle bands. The experimental techniques employed in undertaking studies on the optical spectroscopy of extraterrestrial molecules are described and critiqued in the context of their application.

  1. HAPPINESS AND THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE

    Microsoft Academic Search

    Hans-Jürgen Engelbrecht

    Voluntary non-commercial Internet-based distributed computing ('social sharing' for short) is emerging as a distinct mode of resource allocation and economic production, alongside price- based and hierarchy- (i.e. firm-) based modes. This paper presents a cross-country analysis of the factors determining participation in the classic example of a social sharing project, the Search for Extraterrestrial Intelligence (SETI@home). The key hypothesis tested

  2. Carbonaceous chondritic asteroids - The ideal extraterrestrial resource

    NASA Astrophysics Data System (ADS)

    Kuck, David L.

    It is proposed that carbonaceous chondritic asteroids be used as extraterrestrial resources because they contain biogenic resources, water, hydrocarbons and water soluble metal salts. The chemical composition determined for carbonaceous chondritic asteroids is presented in tables and the processes for extracting iron ore and silicon, aluminum, magnesium, calcium, sulfur, and phosphorus compounds from them are examined. It is suggested that these asteroids could provide valuable resources for lunar and LEO colonies.

  3. Spectral analysis of the effects of 1.7 MeV electron irradiation on the current transfer characteristic of cadmium telluride solar cells.

    PubMed

    Tian, Jin-Xiu; Zeng, Guang-Gen; He, Xu-Lin; Zhang, Jing-Quan; Wu, Li-Li; Li, Wei; Li, Bing; Wang, Wen-Wu; Feng, Liang-Huan

    2014-04-01

    The effects of device performance of 1.7 MeV electron irradiation on cadmium telluride polycrystalline thin film solar cells with the structure of anti-radiation glass/ITO/ZnO/CdS/CdTe/ZnTe/ZnTe : Cu/Ni have been studied. Light and dark I-V characteristics, dark C-V characteristics, quantum efficiency (QE), admittance spectrum (AS) and other testing methods were used to analyze cells performance such as the open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF) and conversion efficiency (eta). It was explored to find out the effects of irradiation on the current transfer characteristic of solar cells combined with the dark current density (Jo), diode ideal factor (A), quantum efficiency, carrier concentration and the depletion layer width. The decline in short-circuit current was very large and the efficiency of solar cells decreased obviously after irradiation. Reverse saturation current density increased, which indicates that p-n junction characteristics of solar cells were damaged, and diode ideal factor was almost the same, so current transport mechanism of solar cells has not changed. Quantum efficiency curves proved that the damage of solar cells' p-n junction influenced the collection of photo-generated carriers. Irradiation made carrier concentration reduce to 40.6%. The analyses have shown that. A new defect was induced by electron irradiation, whose position is close to 0.58 eV above the valence band in the forbidden band, and capture cross section is 1.78 x 10(-16) cm2. These results indicate that irradiation influences the generation of photo-generated carriers, increases the risk of the carrier recombination and the reverse dark current, and eventually makes the short-circuit current of solar cells decay. PMID:25007593

  4. Paleoindian demography and the extraterrestrial impact hypothesis

    PubMed Central

    Buchanan, Briggs; Collard, Mark; Edinborough, Kevan

    2008-01-01

    Recently it has been suggested that one or more large extraterrestrial (ET) objects struck northern North America 12,900 ± 100 calendar years before present (calBP) [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 104: 16016–16021]. This impact is claimed to have triggered the Younger Dryas major cooling event and resulted in the extinction of the North American megafauna. The impact is also claimed to have caused major cultural changes and population decline among the Paleoindians. Here, we report a study in which ?1,500 radiocarbon dates from archaeological sites in Canada and the United States were used to test the hypothesis that the ET resulted in population decline among the Paleoindians. Following recent studies [e.g., Gamble C, Davies W, Pettitt P, Hazelwood L, Richards M (2005) Camb Archaeol J 15:193–223), the summed probability distribution of the calibrated dates was used to identify probable changes in human population size between 15,000 and 9,000 calBP. Subsequently, potential biases were evaluated by modeling and spatial analysis of the dated occupations. The results of the analyses were not consistent with the predictions of extraterrestrial impact hypothesis. No evidence of a population decline among the Paleoindians at 12,900 ± 100 calBP was found. Thus, minimally, the study suggests the extraterrestrial impact hypothesis should be amended. PMID:18697936

  5. Paleoindian demography and the extraterrestrial impact hypothesis.

    PubMed

    Buchanan, Briggs; Collard, Mark; Edinborough, Kevan

    2008-08-19

    Recently it has been suggested that one or more large extraterrestrial (ET) objects struck northern North America 12,900 +/- 100 calendar years before present (calBP) [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 104: 16016-16021]. This impact is claimed to have triggered the Younger Dryas major cooling event and resulted in the extinction of the North American megafauna. The impact is also claimed to have caused major cultural changes and population decline among the Paleoindians. Here, we report a study in which approximately 1,500 radiocarbon dates from archaeological sites in Canada and the United States were used to test the hypothesis that the ET resulted in population decline among the Paleoindians. Following recent studies [e.g., Gamble C, Davies W, Pettitt P, Hazelwood L, Richards M (2005) Camb Archaeol J 15:193-223), the summed probability distribution of the calibrated dates was used to identify probable changes in human population size between 15,000 and 9,000 calBP. Subsequently, potential biases were evaluated by modeling and spatial analysis of the dated occupations. The results of the analyses were not consistent with the predictions of extraterrestrial impact hypothesis. No evidence of a population decline among the Paleoindians at 12,900 +/- 100 calBP was found. Thus, minimally, the study suggests the extraterrestrial impact hypothesis should be amended. PMID:18697936

  6. Normal incidence spectrophotometer using high density transmission grating technology and highly efficiency silicon photodiodes for absolute solar EUV irradiance measurements

    NASA Technical Reports Server (NTRS)

    Ogawa, H. S.; Mcmullin, D.; Judge, D. L.; Korde, R.

    1992-01-01

    New developments in transmission grating and photodiode technology now make it possible to realize spectrometers in the extreme ultraviolet (EUV) spectral region (wavelengths less than 1000 A) which are expected to be virtually constant in their diffraction and detector properties. Time dependent effects associated with reflection gratings are eliminated through the use of free standing transmission gratings. These gratings together with recently developed and highly stable EUV photodiodes have been utilized to construct a highly stable normal incidence spectrophotometer to monitor the variability and absolute intensity of the solar 304 A line. Owing to its low weight and compactness, such a spectrometer will be a valuable tool for providing absolute solar irradiance throughout the EUV. This novel instrument will also be useful for cross-calibrating other EUV flight instruments and will be flown on a series of Hitchhiker Shuttle Flights and on SOHO. A preliminary version of this instrument has been fabricated and characterized, and the results are described.

  7. Study of radiation induced deep-level defects in proton irradiated AlGaAs-GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Li, S. S.

    1980-01-01

    Radiation induced deep-level defects (both electron and hole traps) in proton irradiated AlGaAs-GaAs p-n junction solar cells are investigated along with the correlation between the measured defect parameters and the solar cell performance parameters. The range of proton energies studied was from 50 KeV to 10 MeV and the proton fluence was varied from 10 to the 10th power to 10 to the 13th power P/sq cm. Experimental tools employed include deep-level transient spectroscopy, capacitance-voltage, current voltage, and SEM-EBIC methods. Defect and recombination parameters such as defect density and energy level, capture cross section, carrier lifetimes and effective hole diffusion lengths in n-GaAs LPE layers were determined from these measurements.

  8. A web service for controlling the quality of measurements of global solar irradiation

    Microsoft Academic Search

    M. Geiger; L. Diabaté; L. Ménard; L. Wald

    2002-01-01

    The control of the quality of irradiation data is often a prerequisite to their further processing. Though data are usually controlled by meteorological offices, the sources are so numerous that the user often faces time-series of measurements containing questionable values. As customers of irradiation data, we established our own procedures to screen time-series of measurements. Since this problem of quality

  9. Pros and cons in the search for extraterrestrial intelligence

    Microsoft Academic Search

    S. Sri Kantha

    1996-01-01

    I propose a new term, ‘galactic organism with distinct intelligence’, for the extraterrestrial forms, with which humans can make contact. This is because, among the three existing terms: (a) ‘the search for extraterrestrial intelligence#x02019; ‘excludes biology and is inelegant#x02019; (b) ‘extraterrestrial#x02019; does not distinguish between the micro-organisms and highly-evolved intelligent life-forms; and (c) 'unidentified flying object' projects a sense of

  10. Curating NASA's Extraterrestrial Samples - Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Allen, Carlton; Allton, Judith; Lofgren, Gary; Righter, Kevin; Zolensky, Michael

    2011-01-01

    Curation of extraterrestrial samples is the critical interface between sample return missions and the international research community. The Astromaterials Acquisition and Curation Office at the NASA Johnson Space Center (JSC) is responsible for curating NASA s extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials", JSC is charged with ". . . curation of all extraterrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including "documentation, preservation, preparation, and distribution of samples for research, education, and public outreach."

  11. Curating NASA's Extraterrestrial Samples - Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Allen, Carlton; Allton, Judith; Lofgren, Gary; Righter, Kevin; Zolensky, Michael

    2010-01-01

    Curation of extraterrestrial samples is the critical interface between sample return missions and the international research community. The Astromaterials Acquisition and Curation Office at the NASA Johnson Space Center (JSC) is responsible for curating NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials," JSC is charged with ". . . curation of all extraterrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including documentation, preservation, preparation, and distribution of samples for research, education, and public outreach.

  12. Multi-facet concentrator of solar setup for irradiating the objects placed in a target plane with solar light

    DOEpatents

    Lewandowski, Allan A. (Evergreen, CO); Yampolskiy, Vladislav (Moscow, RU); Alekseev, Valerie (Moscow, RU); Son, Valentin (Moscow, RU)

    2001-01-01

    According to the proposed invention, this technical result is achieved so that many-facet concentrator of a solar setup for exposure of objects, placed in a target plane, to the action of solar radiation containing a supporting frame and facets differing by that the facets of the concentrator are chosen with spherical focusing reflective surfaces of equal focal lengths and with selective coatings reflecting a desired spectral fraction of solar radiation, and are arranged on the supporting frame symmetrically with respect to the common axis of the concentrator, their optical axes being directed to the single point on the optical axis of the concentrator located before the nominal focus point of the concentrator and determining the position of arranging the target plane.

  13. The first disaggregated solar atlas of Djibouti: a decision-making tool for solar systems integration in the energy scheme

    E-print Network

    Paris-Sud XI, Université de

    measured horizons, we observed that error probability on irradiation increased over high mountainous areas Function (BRDF) 0G global horizontal extraterrestrial irradiance (W/m²) hG global horizontal irradiance (W. To realize this atlas, a satellite-based irradiance model is used (EUMETSAT O&SI SAF). To validate this model

  14. Middle atmosphere response to different descriptions of the 11-yr solar cycle in spectral irradiance in a chemistry-climate model

    NASA Astrophysics Data System (ADS)

    Swartz, W. H.; Stolarski, R. S.; Oman, L. D.; Fleming, E. L.; Jackman, C. H.

    2012-03-01

    The 11-yr solar cycle in solar spectral irradiance (SSI) inferred from measurements by the SOlar Radiation & Climate Experiment (SORCE) suggests a much larger variation in the ultraviolet than previously accepted. We present middle atmosphere ozone and temperature responses to the solar cycles in SORCE SSI and the ubiquitous Naval Research Laboratory (NRL) SSI reconstruction using the Goddard Earth Observing System chemistry-climate model (GEOS CCM). The results are largely consistent with other recent modeling studies. The modeled ozone response is positive throughout the stratosphere and lower mesosphere using the NRL SSI, while the SORCE SSI produces a response that is larger in the lower stratosphere but out of phase with respect to total solar irradiance above 45 km. The modeled responses in total ozone are similar to those derived from satellite and ground-based measurements, 3-6 Dobson Units per 100 units of 10.7-cm radio flux (F10.7) in the tropics. The peak zonal mean tropical temperature response using the SORCE SSI is nearly 2 K per 100 units F10.7 - 3 times larger than the simulation using the NRL SSI. The GEOS CCM and the Goddard Space Flight Center (GSFC) 2-D coupled model are used to examine how the SSI solar cycle affects the atmosphere through direct solar heating and photolysis processes individually. Middle atmosphere ozone is affected almost entirely through photolysis, whereas the solar cycle in temperature is caused both through direct heating and photolysis feedbacks, processes that are mostly linearly separable. Further, the net ozone response results from the balance of ozone production at wavelengths less than 242 nm and destruction at longer wavelengths, coincidentally corresponding to the wavelength regimes of the SOLar STellar Irradiance Comparison Experiment (SOLSTICE) and Spectral Irradiance Monitor (SIM) on SORCE, respectively. A higher wavelength-resolution analysis of the spectral response could allow for a better prediction of the atmospheric response to arbitrary SSI variations.

  15. Thermal annealing of GaAs concentrator solar cells. [during electron irradiation

    NASA Technical Reports Server (NTRS)

    Curtis, H. B.; Brinker, D. J.

    1989-01-01

    The thermal annealing of GaAs concentrator cells after electron irradiation is reported. Results are given for cells annealed at 150, 200, and 250 C. Isochronal annealing was done for 20 min intervals up to 350 C. For cells irradiated with electrons of energies between 0.7 and 2.3 MeV, the recovery decreases with increasing electron energy. Isothermal and isochronal annealing produce the same recovery. Cells irradiated to 3 x 10 to the 15th or 1 x 10 to the 16th e/sq cm recover to similar unannealed fractions. Significant annealing is seen starting at 150 C, although very long times are required.

  16. A 24-h forecast of solar irradiance using artificial neural network: Application for performance prediction of a grid-connected PV plant at Trieste, Italy

    SciTech Connect

    Mellit, Adel [Department of Electronics, Faculty of Sciences and Technology, LAMEL, Jijel University, Ouled-aissa, P.O. Box 98, Jijel 18000 (Algeria); Pavan, Alessandro Massi [Department of Materials and Natural Resources, University of Trieste Via A. Valerio, 2 - 34127 Trieste (Italy)

    2010-05-15

    Forecasting of solar irradiance is in general significant for planning the operations of power plants which convert renewable energies into electricity. In particular, the possibility to predict the solar irradiance (up to 24 h or even more) can became - with reference to the Grid Connected Photovoltaic Plants (GCPV) - fundamental in making power dispatching plans and - with reference to stand alone and hybrid systems - also a useful reference for improving the control algorithms of charge controllers. In this paper, a practical method for solar irradiance forecast using artificial neural network (ANN) is presented. The proposed Multilayer Perceptron MLP-model makes it possible to forecast the solar irradiance on a base of 24 h using the present values of the mean daily solar irradiance and air temperature. An experimental database of solar irradiance and air temperature data (from July 1st 2008 to May 23rd 2009 and from November 23rd 2009 to January 24th 2010) has been used. The database has been collected in Trieste (latitude 45 40'N, longitude 13 46'E), Italy. In order to check the generalization capability of the MLP-forecaster, a K-fold cross-validation was carried out. The results indicate that the proposed model performs well, while the correlation coefficient is in the range 98-99% for sunny days and 94-96% for cloudy days. As an application, the comparison between the forecasted one and the energy produced by the GCPV plant installed on the rooftop of the municipality of Trieste shows the goodness of the proposed model. (author)

  17. Investigation of light and dark IV characteristics of aSi:H alloy solar cells, irradiated with 1.0 MeV protons

    Microsoft Academic Search

    Kenneth R. Lord; Michael R. Walters; James R. Woodyard

    1993-01-01

    Light and dark I-V characteristics of both virgin and irradiated solar cells with the same history differ; the objective of this work is to elucidate the mechanisms responsible for the observations. Thirty-seven triple-junction and 120 single-junction hydrogenated amorphous silicon alloy cells were investigated. Triple and single-junction cells degrade similarly with 1.0 MeV proton irradiation; the power density degrades for fluences

  18. Radiation damage and defect behavior in proton irradiated lithium-counterdoped n+p silicon solar cells

    NASA Technical Reports Server (NTRS)

    Stupica, John; Goradia, Chandra; Swartz, Clifford K.; Weinberg, Irving

    1987-01-01

    Two lithium-counterdoped n+p silicon solar cells with different lithium concentrations were irradiated by 10-MeV protons. Cell performance was measured as a function of fluence, and it was found that the cell with the highest concentration of lithium had the highest radiation resistance. Deep level transient spectroscopy which showed two deep level defects that were lithium related. Relating the defect energy levels obtained from this study with those from earlier work using 1-MeV electron irradiation shows no correlation of the defect energy levels. There is one marked similarity: the absence of the boron-interstitial-oxygen-interstitial defect. This consistency strengthens the belief that lithium interacts with oxygen to prevent the formation of the boron interstitial-oxygen interstitial defect. The results indicate that, in general, addition of lithium in small amounts to the p-base of a boron doped silicon solar cell such that the base remains p-type, tends to increase the radiation resistance of the cell.

  19. On the likelihood of non-terrestrial artifacts in the Solar System

    Microsoft Academic Search

    Jacob Haqq-Misra; Ravi Kumar Kopparapu

    2011-01-01

    Extraterrestrial technology may exist in the Solar System without our knowledge. This is because the vastness of space, combined with our limited searches to date, implies that any remote unpiloted exploratory probes of extraterrestrial origin would likely remain unnoticed. Here we develop a probabilistic approach to quantify our certainty (or uncertainty) of the existence of such technology in the Solar

  20. SPM characterization of next generation solar cells under light irradiation: Optoelectronic study from nano to macroscopic scale.

    PubMed

    Ishida, Nobuyuki; Fujita, Daisuke

    2014-11-01

    Solar cells (SCs) that contain elaborate nanostructures, such as quantum dots and quantum wells, have been rigorously investigated as a way to harvest a wide range of the solar spectrum [1]. However, the energy conversion efficiency of those SCs still remains low. For the further improvement of the device performance, a much deeper understanding of the role of nanostructures in the photovoltaic conversion process is essential to gain the effective design criteria. To achieve this, local electronic properties including electrical potential, energy states, and charge distribution around the excitation centers have to be characterized under light irradiation since they govern the behavior of excited carriers. These properties have so far been indirectly deduced from macroscopic characterization such as current-voltage (I-V) measurement; however, it is not sufficient to clarify rather complicated roles of the nanostructures [2]. Thus, a direct measurement of those properties with high spatial resolution is required to understand the detailed mechanisms of the photovoltaic conversion process. To this end, we have been developing a platform for performing scanning tunneling microscopy/spectroscopy (STM/STS), atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM) working under light irradiation conditions.Here, we outline the characterization of a multiple quantum well (QW) SC based on III-V compounds that is expected to be a potential candidate of intermediate band type SC. First, we show the electrical potential measurements along the p-i-n junction of the SC using KPFM in air. Measurements were performed in open and short circuit configurations under light irradiation conditions [Fig.1]. We demonstrate that the dependence of the open circuit voltage on the intensity of light can be successfully measured by careful interpretation of the KPFM data. Second, we introduce some examples of the atomic scale characterization of the multiple QW using ultrahigh vacuum STM including the atomic arrangement, electronic states, and band profile. Also, charge accumulation at the QW is discussed based on the topographic measurement under light irradiation.jmicro;63/suppl_1/i12/DFU042F1F1DFU042F1Fig. 1.(a) Schematic illustration of measurement system of KPFM in air. (b) Effect of light irradiation on potential profile in open circuit configuration. PMID:25359801