WorldWideScience

Sample records for modeling total solar

  1. Daily total global solar radiation modeling from several meteorological data

    Science.gov (United States)

    Bilgili, Mehmet; Ozgoren, Muammer

    2011-05-01

    This paper investigates the modeling of the daily total global solar radiation in Adana city of Turkey using multi-linear regression (MLR), multi-nonlinear regression (MNLR) and feed-forward artificial neural network (ANN) methods. Several daily meteorological data, i.e., measured sunshine duration, air temperature and wind speed and date of the year, i.e., monthly and daily, were used as independent variables to the MLR, MNLR and ANN models. In order to determine the relationship between the total global solar radiation and other meteorological data, and also to obtain the best independent variables, the MLR and MNLR analyses were performed with the "Stepwise" method in the Statistical Packages for the Social Sciences (SPSS) program. Thus, various models consisting of the combination of the independent variables were constructed and the best input structure was investigated. The performances of all models in the training and testing data sets were compared with the measured daily global solar radiation values. The obtained results indicated that the ANN method was better than the other methods in modeling daily total global solar radiation. For the ANN model, mean absolute error (MAE), mean absolute percentage error (MAPE), correlation coefficient ( R) and coefficient of determination ( R 2) for the training/testing data set were found to be 0.89/1.00 MJ/m2 day, 7.88/9.23%, 0.9824/0.9751, and 0.9651/0.9508, respectively.

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

    CERN Document Server

    Moore, Christopher Samuel; Hock, Rachel

    2015-01-01

    The Total Irradiance Monitor (TIM) from NASA's SOlar Radiation and Climate Experiment (SORCE) 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 ares 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 ares presented in Woods et al. (2006), as well as an additional are measured on 2006 December 6. The radiative outputs for both phases of these five ares 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 ares. This model provides the basis for the bolometric energy estimates for the solar ares analyzed in the Emslie et al. (2012) study.

  3. Coronal structure analysis based on the potential field source surface modeling and total solar eclipse observation

    Science.gov (United States)

    Muhamad, Johan; Mumtahana, Farahhati; Sutastio, Heri; Imaduddin, Irfan; Putri, Gerhana P.

    2016-11-01

    We constructed global coronal magnetic fields of the Sun during the Total Solar Eclipse (TSE) 9 March 2016 by using Potential Field Source Surface (PFSS) model. Synoptic photospheric magnetogram data from Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO) was used as a boundary condition to extrapolate the coronal magnetic fields of the Sun. This extrapolated structure was analyzed by comparing the alignment of the fields from the model with coronal structure from the observation. We also used observational data of coronal structure during the total solar eclipse to know how well the model agree with the observation. As a result, we could identify several coronal streamers which were produced by the large closed loops in the lower regime of the corona. This result verified that the PFSS extrapolation can be used as a tool to model the inner corona with several constraints. We also discussed how the coronal structure can be used to deduce the phase of the solar cycle.

  4. ACRIM total solar irradiance satellite composite validation versus TSI proxy models

    CERN Document Server

    Scafetta, Nicola

    2014-01-01

    The satellite total solar irradiance (TSI) database provides a valuable record for investigating models of solar variation used to interpret climate changes. The 35-year ACRIM TSI satellite composite was updated using corrections to ACRIMSAT/ACRIM3 results derived from recent testing at the Laboratory for Atmospheric and Space Physics/Total solar irradiance Radiometer Facility (LASP/TRF). The corrections lower the ACRIM3 scale by ~5000 ppm, in close agreement with the scale of SORCE/TIM results (solar constant ~1361 W/m^2). Relative variations and trends are not changed. Differences between the ACRIM and PMOD TSI composites, e.g. the decadal trending during solar cycles 21-22, are tested against a set of solar proxy models, including analysis of Nimbus7/ERB and ERBS/ERBE results available to bridge the ACRIM Gap (1989-1992). Our findings confirm: (1) The validity of the TSI peak in the originally published ERB results in early 1979 during solar cycle 21; (2) The correctness of originally published ACRIM1 resu...

  5. An adaptive wavelet-network model for forecasting daily total solar-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mellit, A. [University Centre of Medea (CUYFM), Institute of Engineering Sciences, Department of Electronics, Medea (Algeria). Department of Electrical Engineering, Faculty of Engineering; Benghanem, M. [University of Sciences Technology Houari Boumediene (USTHB), Algiers (Algeria). Faculty of Electrical Engineering; Kalogirou, S.A. [Higher Technical Institute, Nicosia (Cyprus). Department of Mechanical Engineering

    2006-07-15

    The combination of wavelet theory and neural networks has lead to the development of wavelet networks. Wavelet-networks are feed-forward networks using wavelets as activation functions. Wavelet-networks have been used successfully in various engineering applications such as classification, identification and control problems. In this paper, the use of adaptive wavelet-network architecture in finding a suitable forecasting model for predicting the daily total solar-radiation is investigated. Total solar-radiation is considered as the most important parameter in the performance prediction of renewable energy systems, particularly in sizing photovoltaic (PV) power systems. For this purpose, daily total solar-radiation data have been recorded during the period extending from 1981 to 2001, by a meteorological station in Algeria. The wavelet-network model has been trained by using either the 19 years of data or one year of the data. In both cases the total solar radiation data corresponding to year 2001 was used for testing the model. The network was trained to accept and handle a number of unusual cases. Results indicate that the model predicts daily total solar-radiation values with a good accuracy of approximately 97% and the mean absolute percentage error is not more than 6%. In addition, the performance of the model was compared with different neural network structures and classical models. Training algorithms for wavelet-networks require smaller numbers of iterations when compared with other neural networks. The model can be used to fill missing data in weather databases. Additionally, the proposed model can be generalized and used in different locations and for other weather data, such as sunshine duration and ambient temperature. Finally, an application using the model for sizing a PV-power system is presented in order to confirm the validity of this model. (author)

  6. Solar irradiance, total and spectral; Irradiancia solar, total e espectral

    Energy Technology Data Exchange (ETDEWEB)

    Fraidenraich, Naum [Pernambuco Univ., Recife, PE (Brazil). Centro de Energia Nuclear; Lyra, Francisco [Companhia Hidroeletrica do Sao Francisco (CHESF), Recife, PE (Brazil)

    1995-12-31

    In this chapter some important characteristics concerning solar irradiance are presented, such as: solar constant; spectral irradiance for a zeroed mass of air; solar constant variation according to Earth-Sun distance; solar energy variation on Earth`s surface; atmospheric attenuation of solar energy; and total radiation and spectral irradiation on Earth`s surface. 3 refs., 5 figs., 6 tabs.

  7. A Different View of Solar Spectral Irradiance Variations: Modeling Total Energy over Six-Month Intervals.

    Science.gov (United States)

    Woods, Thomas N; Snow, Martin; Harder, Jerald; Chapman, Gary; Cookson, Angela

    A different approach to studying solar spectral irradiance (SSI) variations, without the need for long-term (multi-year) instrument degradation corrections, is examining the total energy of the irradiance variation during 6-month periods. This duration is selected because a solar active region typically appears suddenly and then takes 5 to 7 months to decay and disperse back into the quiet-Sun network. The solar outburst energy, which is defined as the irradiance integrated over the 6-month period and thus includes the energy from all phases of active region evolution, could be considered the primary cause for the irradiance variations. Because solar cycle variation is the consequence of multiple active region outbursts, understanding the energy spectral variation may provide a reasonable estimate of the variations for the 11-year solar activity cycle. The moderate-term (6-month) variations from the Solar Radiation and Climate Experiment (SORCE) instruments can be decomposed into positive (in-phase with solar cycle) and negative (out-of-phase) contributions by modeling the variations using the San Fernando Observatory (SFO) facular excess and sunspot deficit proxies, respectively. These excess and deficit variations are fit over 6-month intervals every 2 months over the mission, and these fitted variations are then integrated over time for the 6-month energy. The dominant component indicates which wavelengths are in-phase and which are out-of-phase with solar activity. The results from this study indicate out-of-phase variations for the 1400 - 1600 nm range, with all other wavelengths having in-phase variations.

  8. Heliophysics at total solar eclipses

    Science.gov (United States)

    Pasachoff, Jay M.

    2017-08-01

    Observations during total solar eclipses have revealed many secrets about the solar corona, from its discovery in the 17th century to the measurement of its million-kelvin temperature in the 19th and 20th centuries, to details about its dynamics and its role in the solar-activity cycle in the 21st century. Today's heliophysicists benefit from continued instrumental and theoretical advances, but a solar eclipse still provides a unique occasion to study coronal science. In fact, the region of the corona best observed from the ground at total solar eclipses is not available for view from any space coronagraphs. In addition, eclipse views boast of much higher quality than those obtained with ground-based coronagraphs. On 21 August 2017, the first total solar eclipse visible solely from what is now United States territory since long before George Washington's presidency will occur. This event, which will cross coast-to-coast for the first time in 99 years, will provide an opportunity not only for massive expeditions with state-of-the-art ground-based equipment, but also for observations from aloft in aeroplanes and balloons. This set of eclipse observations will again complement space observations, this time near the minimum of the solar activity cycle. This review explores the past decade of solar eclipse studies, including advances in our understanding of the corona and its coronal mass ejections as well as terrestrial effects. We also discuss some additional bonus effects of eclipse observations, such as recreating the original verification of the general theory of relativity.

  9. New Techniques Used in Modeling the 2017 Total Solar Eclipse: Energizing and Heating the Large-Scale Corona

    Science.gov (United States)

    Downs, Cooper; Mikic, Zoran; Linker, Jon A.; Caplan, Ronald M.; Lionello, Roberto; Torok, Tibor; Titov, Viacheslav; Riley, Pete; Mackay, Duncan; Upton, Lisa

    2017-08-01

    Over the past two decades, our group has used a magnetohydrodynamic (MHD) model of the corona to predict the appearance of total solar eclipses. In this presentation we detail recent innovations and new techniques applied to our prediction model for the August 21, 2017 total solar eclipse. First, we have developed a method for capturing the large-scale energized fields typical of the corona, namely the sheared/twisted fields built up through long-term processes of differential rotation and flux-emergence/cancellation. Using inferences of the location and chirality of filament channels (deduced from a magnetofrictional model driven by the evolving photospheric field produced by the Advective Flux Transport model), we tailor a customized boundary electric field profile that will emerge shear along the desired portions of polarity inversion lines (PILs) and cancel flux to create long twisted flux systems low in the corona. This method has the potential to improve the morphological shape of streamers in the low solar corona. Second, we apply, for the first time in our eclipse prediction simulations, a new wave-turbulence-dissipation (WTD) based model for coronal heating. This model has substantially fewer free parameters than previous empirical heating models, but is inherently sensitive to the 3D geometry and connectivity of the coronal field---a key property for modeling/predicting the thermal-magnetic structure of the solar corona. Overall, we will examine the effect of these considerations on white-light and EUV observables from the simulations, and present them in the context of our final 2017 eclipse prediction model.Research supported by NASA's Heliophysics Supporting Research and Living With a Star Programs.

  10. Modeling of the lower ionospheric response and VLF signal modulation during a total solar eclipse using ionospheric chemistry and LWPC

    Science.gov (United States)

    Chakraborty, Suman; Palit, Sourav; Ray, Suman; Chakrabarti, Sandip K.

    2016-02-01

    The variation in the solar Extreme Ultraviolet (EUV) radiation flux by any measure is the most dominant natural source to produce perturbations or modulations in the ionospheric chemical and plasma properties. A solar eclipse, though a very rare phenomenon, is similarly bound to produce a significant short time effect on the local ionospheric properties. The influence of the ionizing solar flux reduction during a solar eclipse on the lower ionosphere or, more precisely, the D-region, can be studied with the observation of Very Low Frequency (VLF) radio wave signal modulation. The interpretation of such an effect on VLF signals requires a knowledge of the D-region ion chemistry, which is not well studied till date. Dominant parameters which govern the ion chemistry, such as the recombination coefficients, are poorly known. The occurrence of events such as a solar eclipse provides us with an excellent opportunity to investigate the accuracy of our knowledge of the chemical condition in this part of Earth's atmosphere and the properties which control the ionospheric stability under such disturbances. In this paper, using existing knowledge of the lower ionospheric chemical and physical properties we carry out an interpretation of the effects obtained during the total solar eclipse of 22 of July 2009 on the VLF signal. Data obtained from a week long campaign conducted by the Indian Centre for Space Physics (ICSP) over the Indian subcontinent has been used for this purpose. Both positive and negative amplitude changes during the eclipse were observed along various receiver locations. In this paper, data for a propagation path between a Indian Navy VLF transmitter named VTX3 and a pair of receivers in India are used. We start from the observed solar flux during the eclipse and calculate the ionization during the whole time span over most of the influenced region in a range of height. We incorporate a D-region ion-chemistry model to find the equilibrium ion density over

  11. The Total Solar Eclipse, March 1970

    Science.gov (United States)

    Glenn, William H.

    1970-01-01

    Describes the circumstances of the total and partial solar eclipse of March 7, 1970 in certain American cities. Also discussed are (1) a classroom demonstration of the cause of solar eclipses, (2) techniques for safely observing the eclipse, and (3) what to observe during the eclipse. Bibliography. (LC)

  12. The Total Solar Eclipse, March 1970

    Science.gov (United States)

    Glenn, William H.

    1970-01-01

    Describes the circumstances of the total and partial solar eclipse of March 7, 1970 in certain American cities. Also discussed are (1) a classroom demonstration of the cause of solar eclipses, (2) techniques for safely observing the eclipse, and (3) what to observe during the eclipse. Bibliography. (LC)

  13. Total Solar Eclipse--A Caribbean Adventure.

    Science.gov (United States)

    Green, Steven; Tunstall, Louisa; Tunstall, Neil

    1999-01-01

    Describes the experiences of two high school students who traveled to the Caribbean island of Curacao to view a total solar eclipse and prepare methods for teaching classmates about the eclipse the following school year. (Author/WRM)

  14. Total Solar Eclipse--A Caribbean Adventure.

    Science.gov (United States)

    Green, Steven; Tunstall, Louisa; Tunstall, Neil

    1999-01-01

    Describes the experiences of two high school students who traveled to the Caribbean island of Curacao to view a total solar eclipse and prepare methods for teaching classmates about the eclipse the following school year. (Author/WRM)

  15. A new reconstruction of total solar irradiance since 1832

    Energy Technology Data Exchange (ETDEWEB)

    Vaquero, J.M. [Departamento de Fisica, Escuela Politecnica, Universidad de Extremadura, Caceres (Spain); Gallego, M.C. [Departamento de Fisica, Universidad de Extremadura, Badajoz (Spain); Trigo, R.M. [Centro de Geofisica da Universidade de Lisboa, Departamento de Engenharias, Lisboa (Portugal); Sanchez-Bajo, F [Escuela de Ingenieros Industriales, Universidad de Extremadura, Badajoz (Spain); Cancillo, M.L.; Garcia, J.A. [Departamento de Fisica, Universidad de Extremadura, Badajoz (Spain)

    2006-10-15

    Variations of solar irradiance (total and spectral) are quantities purported to have an influence on climate. The aim of this paper is to reconstruct the total solar irradiance from 1832 to the present. The contributions of active regions and the quiet sun are modelled separately using the method developed by Solanki and Fligge (1999). The areas of sunspots observed since 1832 are used to compute the contribution of active regions to the irradiance changes. [Spanish] Diferentes autores han propuesto que las variaciones de la irradiancia solar total y espectral son magnitudes que pueden influir en el clima. El objetivo de este articulo es reconstruir la irradiancia solar total desde 1832 hasta el presente. Las contribuciones de las regiones activas y del 'sol quieto' se modelan separadamente usando el metodo de Solanki y Fligge (1999). El area de las manchas solares desde 1832 es utilizada para calcular la contribucion de las regiones activas a los cambios en la irradiancia.

  16. SORCE Level 3 Total Solar Irradiance Daily Average V016

    Data.gov (United States)

    National Aeronautics and Space Administration — The Total Solar Irradiance (TSI) data set SOR3TSID contains the total solar irradiance (a.k.a solar constant) data collected by the Total Irradiance Monitor (TIM)...

  17. A reconstruction of radiocarbon production and total solar irradiance from the Holocene 14C and CO2 records: implications of data and model uncertainties

    Directory of Open Access Journals (Sweden)

    R. Roth

    2013-08-01

    Full Text Available Radiocarbon production, solar activity, total solar irradiance (TSI and solar-induced climate change are reconstructed for the Holocene (10 to 0 kyr BP, and TSI is predicted for the next centuries. The IntCal09/SHCal04 radiocarbon and ice core CO2 records, reconstructions of the geomagnetic dipole, and instrumental data of solar activity are applied in the Bern3D-LPJ, a fully featured Earth system model of intermediate complexity including a 3-D dynamic ocean, ocean sediments, and a dynamic vegetation model, and in formulations linking radiocarbon production, the solar modulation potential, and TSI. Uncertainties are assessed using Monte Carlo simulations and bounding scenarios. Transient climate simulations span the past 21 thousand years, thereby considering the time lags and uncertainties associated with the last glacial termination. Our carbon-cycle-based modern estimate of radiocarbon production of 1.7 atoms cm−2 s−1 is lower than previously reported for the cosmogenic nuclide production model by Masarik and Beer (2009 and is more in-line with Kovaltsov et al. (2012. In contrast to earlier studies, periods of high solar activity were quite common not only in recent millennia, but throughout the Holocene. Notable deviations compared to earlier reconstructions are also found on decadal to centennial timescales. We show that earlier Holocene reconstructions, not accounting for the interhemispheric gradients in radiocarbon, are biased low. Solar activity is during 28% of the time higher than the modern average (650 MeV, but the absolute values remain weakly constrained due to uncertainties in the normalisation of the solar modulation to instrumental data. A recently published solar activity–TSI relationship yields small changes in Holocene TSI of the order of 1 W m−2 with a Maunder Minimum irradiance reduction of 0.85 ± 0.16 W m−2. Related solar-induced variations in global mean surface air temperature are simulated to be within 0

  18. Scientific observations at total solar eclipses

    Institute of Scientific and Technical Information of China (English)

    Jay M.Pasachoff

    2009-01-01

    The occasion of the longest totality of an eclipse in the 18 yr 111/3 d saros cycle leads to taking stock of the scientific value of ground-based eclipse observations in this space age. Though a number of space satellites from the U.S., Europe, Japan, and Russia study the Sun, scientists at eclipses can observe the solar chromosphere and corona at higher spatial resolution, at higher temporal resolution, and at higher spectral resolution than are possible aloft. Furthermore, eclipse expeditions can transport a wide variety of state-of-the-art equipment to the path of totality. Thus, for at least some years to come, solar eclipse observations will remain both scientifically valuable and cost-effective ways to study the outer solar atmosphere.

  19. Annular and Total Solar Eclipses of 2010

    Science.gov (United States)

    Espenak, Fred; Anderson, J.

    2008-01-01

    While most NASA eclipse bulletins cover a single eclipse, this publication presents predictions for two solar eclipses during 2010. This has required a different organization of the material into the following sections. Section 1 -- Eclipse Predictions: The section consists of a general discussion about the eclipse path maps, Besselian elements, shadow contacts, eclipse path tables, local circumstances tables, and the lunar limb profile. Section 2 -- Annular Solar Eclipse of 2010 Ja n 15: The section covers predictions and weather prospects for the annular eclipse. Section 3 -- Total Solar Eclipse of 2010 Jul 11: The se ction covers predictions and weather prospects for the total eclipse. Section 4 -- Observing Eclipses: The section provides information on eye safety, solar filters, eclipse photography, and making contact timings from the path limits. Section 5 -- Eclipse Resources: The final section contains a number of resources including information on the IAU Working Group on Eclipses, the Solar Eclipse Mailing List, the NASA eclipse bulletins on the Internet, Web sites for the two 2010 eclipses, and a summary identifying the algorithms, ephemerides, and paramete rs used in the eclipse predictions.

  20. The satellite total solar irradiance database

    Science.gov (United States)

    Willson, R. C.

    2009-12-01

    A precise knowledge of the total solar irradiance (TSI) over time is essential to understanding the physics of solar luminosity variation and its impact on the Earth in the form of climate change. A National Research Council study found that sustained trends as small as 0.25% per century were the most likely forcing for ‘little ice age’ climate minima during the 12th - 19th centuries. Recent phenomenological analyses of TSI observations and proxies indicate that TSI variation is an important climate change forcing on many timescales including the industrial era. The profound sociological and economic implications of understanding the relative climate change contributions of natural and anthropogenic forcings makes it essential that the satellite TSI database be precisely sustained into the foreseeable future. There are currently three satellite TSI monitoring experiments in operation: SOHO/VIRGO, ACRIMSAT/ACRIM3 and SORCE/TIM, in order of deployment (1996, 2000 and 2003, resp.). Results reported on their ‘native scales show the same basic variations in TSI over time, yet some smaller variations detected by ACRIM3 are less well defined or absent in the results of VIRGO and TIM. There is also a scale difference issue: TIM results are 0.35% lower than those of ACRIM3 and VIRGO, outside the ± 0.1% uncertainty bounds predicted for ACRIM3 and VIRGO, and well outside TIM’s ± 0.01% uncertainty design goal. TIM’s failure to achieve 0.01% uncertainty in flight demonstrates that the TSI monitoring paradigm shift of relying on measurement accuracy rather than a redundant/overlap strategy to provide long term traceability cannot be realized with current ‘ambient temperature’ technology. The only viable monitoring approach for the foreseeable future continues to be the redundant/overlap strategy that has provided the 31 year satellite TSI database to date with useful traceability. Intercomparisons of flight experiments at their levels of mutual precision can

  1. Paper Moon: Simulating a Total Solar Eclipse

    Science.gov (United States)

    Madden, Sean P.; Downing, James P.; Comstock, Jocelyne M.

    2006-01-01

    This article describes a classroom activity in which a solar eclipse is simulated and a mathematical model is developed to explain the data. Students use manipulative devices and graphing calculators to carry out the experiment and then compare their results to those collected in Koolymilka, Australia, during the 2002 eclipse.

  2. Paper Moon: Simulating a Total Solar Eclipse

    Science.gov (United States)

    Madden, Sean P.; Downing, James P.; Comstock, Jocelyne M.

    2006-01-01

    This article describes a classroom activity in which a solar eclipse is simulated and a mathematical model is developed to explain the data. Students use manipulative devices and graphing calculators to carry out the experiment and then compare their results to those collected in Koolymilka, Australia, during the 2002 eclipse.

  3. Sky color near the horizon during a total solar eclipse.

    Science.gov (United States)

    Gedzelman, S D

    1975-12-01

    A theory for the color of the sky near the horizon for an observer in the umbral region of a total solar eclipse is presented. The model uses a Rayleigh scattering atmosphere, and the light reaching the observer is a beam of singly scattered sunlight, which, in turn, has suffered depletion by scattering in its passage from outside the shadow region. The model predicts both the red color observed in the lowest 8 degrees of the sky for the total solar eclipse of 30 June 1973 and the enriched blue color of the sky at any elevation angle greater than the solar elevation angle. The model is also adapted to explain the reddening of the horizon sky observed during such times as when a dark cloud passes overhead or when the light from a large city is seen from the distance at night.

  4. Solar total irradiance in cycle 23

    CERN Document Server

    Krivova, N A; Schmutz, W

    2011-01-01

    The apparently unusual behaviour of the TSI during the most recent minimum of solar activity has been interpreted as evidence against solar surface magnetism as the main driver of the secular change in the TSI. We test claims that the evolution of the solar surface magnetic field does not reproduce the observed TSI in cycle 23. We use sensitive, 60-minute averaged MDI magnetograms and quasi-simultaneous continuum images as an input to our SATIRE-S model and calculate the TSI variation over cycle 23, sampled roughly twice-monthly. The computed TSI is then compared to the PMOD composite of TSI measurements and to the data from two individual instruments, SORCE/TIM and UARS/ACRIM II, that monitored the TSI during the declining phase of cycle 23 and over the previous minimum in 1996, respectively. Excellent agreement is found between the trends shown by the model and almost all sets of measurements. The only exception is the early, i.e. 1996 to 1998, PMOD data. Whereas the agreement between the model and the PMOD...

  5. VLF signal modulations during the total solar eclipse of 22nd July, 2009: model using D region ion chemistry and LWPC

    Science.gov (United States)

    Chakraborty, Suman; Chakrabarti, Sandip Kumar; Palit, Sourav; Ray, Suman

    2016-07-01

    One of the major sources of ionospheric perturbations is variations in solar Extreme Ultraviolet (EUV) radiation flux. Solar eclipse is a phenomenon which is capable of producing significant effects on the physical and chemical properties of the ionospheric plasma. During a solar eclipse, the solar radiation flux reduces considerably for a limited period of time over specific locations on the Earth. This induces certain changes within the ionosphere or more precisely, in the D-region which can be studied with the observation of Very Low Frequency (VLF) radio signal modulations. The parameters which mainly govern the ion-chemistry, such as the recombination coefficients are poorly known till date. Solar eclipse provides us with an excellent opportunity to study these parameters as its time of occurrence is known beforehand and thus we can equip ourselves accordingly. In the present study we considered the Total Solar Eclipse (TSE) that occurred on 22nd July, 2009 within the Indian subcontinent. Indian Centre for Space Physics (ICSP) conducted a week long campaign during the eclipse and data were recorded from dozens of places within India and abroad. Both positive and negative changes in VLF signal amplitude were observed. In this paper, data for a propagation path between Indian Navy VLF transmitter named VTX3 and a pair of receivers in India, namely Malda and Kolkata are used. We start with calculating the obscuration function for these two places to find the variations in ionization flux within the period of the eclipse. After this, we incorporated the D region ion chemistry model to find the equilibrium ion density over the region and employ the LWPC code to find the VLF signal amplitude. We varied the values of recombination coefficients to achieve desired accuracy in our results. In doing so, we achieved two goals: First, we have been able to reproduce the trend of variation in VLF signal amplitude (both positive and negative) at both the receiving locations

  6. The Total Solar Eclipse of March 2006: overview

    Directory of Open Access Journals (Sweden)

    E. Gerasopoulos

    2007-12-01

    Full Text Available This paper provides an overview of integrated, multi-disciplinary effort to study the effects of a total solar eclipse on the environment, with special focus on the atmosphere. On the occasion of the 29 March 2006 total solar eclipse, visible over the Eastern Mediterranean, several research and academic institutes organised co-ordinated experimental campaigns, at different distances from the totality and in various environments in terms of air quality. The detailed results are presented in a number of scientific papers included in a Special Issue of Atmospheric Chemistry and Physics. The effects of the eclipse on the meteorology and the spectral solar radiation, the chemical response of the atmosphere to the abrupt "switch off" of the sun and the induced changes in the stratosphere and the ionosphere, have been among the issues covered. The rare event of a total solar eclipse provided the opportunity to evaluate 1-D and 3-D radiative transfer models (in the atmosphere and underwater, mesoscale meteorological, regional air quality and photochemical box models, against measurements. Within the challenging topics of this effort has been the investigation of eclipse impacts on ecosystems (field crops and marine plankton and the identification of eclipse induced gravity waves, for the first time with simultaneous measurements at three altitudes namely the troposphere, the stratosphere and the ionosphere.

  7. Predicting the Structure of the Solar Corona During the December 4, 2002 Total Solar Eclipse

    Science.gov (United States)

    Mikic, Zoran; Linker, Jon A.; Riley, Pete; Lionello, Roberto

    2003-01-01

    The solar magnetic field plays a key role in determining coronal. The principal input to MHD models is the observed solar magnetic field. 3D MHD models can be used to compare with eclipse and coronograph images, SOHO images (LOSCO, EIT), Ulysses and WIND spacecraft data, and interplanetary scintillation (IPS) measurements. MHD computations can tell us about the structure of the corona. Eclipses can help us to verify the accuracy of the models. 4 December, 2002 total eclipce: visible in the southern hemisphere (South Atlantic, southern Africa, Indian Ocean, and Australia). Total in center Angola is at 06:00 UT.

  8. Precise estimation of total solar radiation on tilted surface

    African Journals Online (AJOL)

    rajeev

    Key words: Correction factor, meteorological parameters, solar radiation. INTRODUCTION ... Incident solar radiation is calculated directly from the geometry of the model and using hourly recordings of direct beam and diffuse horizontal solar ...

  9. Coronal Dynamics at Recent Total Solar Eclipses

    Science.gov (United States)

    Pasachoff, J. M.; Lu, M.; Davis, A. B.; Demianski, M.; Rusin, V.; Saniga, M.; Seaton, D. B.; Lucas, R.; Babcock, B. A.; Dantowitz, R.; Gaintatzis, P.; Seeger, C. H.; Malamut, C.; Steele, A.

    2014-12-01

    Our composite images of the solar corona based on extensive imaging at the total solar eclipses of 2010 (Easter Island), 2012 (Australia), and 2013 (Gabon) reveal several coronal mass ejections and other changes in coronal streamers and in polar plumes. Our resultant spatial resolution is finer than that available in imaging from spacecraft, including that from SOHO/LASCO or STEREO. We trace the eruptions back to their footpoints on the sun using imaging from SDO and SWAP, and follow them upwards through the corona, measuring velocities. The high-resolution computer compositing by Miloslav Druckmüller and Hana Druckmüllerová (2010 and 2013) and Pavlos Gaintatzis (2012) allows comparison of our images with those taken at intervals of minutes or hours along the totality path. Williams College's 2013 eclipse expedition was supported in part by grant 9327-13 from National Geographic Society/Committee for Research and Exploration. Our work on the 2012 eclipse is supported in part by grant AGS-1047726 from Solar Terrestrial Research/NSF AGS. V.R. and M.S. were partially supported by the VEGA grant agency project 2/0098/10 and 2/0003/13 (Slovak Academy of Sciences) and Grant 0139-12 from NG/CRE, and Hana Druckmüllerová by grant 205/09/1469 of the Czech Science Foundation. M.L. was supported by Sigma Xi. C.M. was a Keck Northeast Astronomy Consortium Summer Fellow, supported at Williams College by REU/NSF grant AST-1005024. Partial support was provided by U.S. Department of Defense's ASSURE program. J.M.P. thanks Caltech's Planetary Sciences Department for hospitality. Support for D.B.S. and SWAP came from PRODEX grant C90345 managed by ESA in collaboration with the Belgian Federal Science Policy Office (BELSPO) in support of the PROBA2/SWAP mission, and from the EC's Seventh Framework Programme (FP7/2007-2013) under grant 218816 (SOTERIA project, www.soteria-space.eu). SWAP is a project of the Centre Spatial de Liège and the Royal Observatory of Belgium funded by

  10. Near-term Forecasting of Solar Total and Direct Irradiance for Solar Energy Applications

    Science.gov (United States)

    Long, C. N.; Riihimaki, L. D.; Berg, L. K.

    2012-12-01

    Integration of solar renewable energy into the power grid, like wind energy, is hindered by the variable nature of the solar resource. One challenge of the integration problem for shorter time periods is the phenomenon of "ramping events" where the electrical output of the solar power system increases or decreases significantly and rapidly over periods of minutes or less. Advance warning, of even just a few minutes, allows power system operators to compensate for the ramping. However, the ability for short-term prediction on such local "point" scales is beyond the abilities of typical model-based weather forecasting. Use of surface-based solar radiation measurements has been recognized as a likely solution for providing input for near-term (5 to 30 minute) forecasts of solar energy availability and variability. However, it must be noted that while fixed-orientation photovoltaic panel systems use the total (global) downwelling solar radiation, tracking photovoltaic and solar concentrator systems use only the direct normal component of the solar radiation. Thus even accurate near-term forecasts of total solar radiation will under many circumstances include inherent inaccuracies with respect to tracking systems due to lack of information of the direct component of the solar radiation. We will present examples and statistical analyses of solar radiation partitioning showing the differences in the behavior of the total/direct radiation with respect to the near-term forecast issue. We will present an overview of the possibility of using a network of unique new commercially available total/diffuse radiometers in conjunction with a near-real-time adaptation of the Shortwave Radiative Flux Analysis methodology (Long and Ackerman, 2000; Long et al., 2006). The results are used, in conjunction with persistence and tendency forecast techniques, to provide more accurate near-term forecasts of cloudiness, and both total and direct normal solar irradiance availability and

  11. Predicting total solar irradiation values using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Mubiru, J. [Department of Physics, Makerere University, P.O. Box 7062, Kampala (Uganda)

    2008-10-15

    This study explores the possibility of developing an artificial neural networks model that could be used to predict monthly average daily total solar irradiation on a horizontal surface for locations in Uganda based on geographical and meteorological data: latitude, longitude, altitude, sunshine duration, relative humidity and maximum temperature. Results have shown good agreement between the predicted and measured values of total solar irradiation. A correlation coefficient of 0.997 was obtained with mean bias error of 0.018 MJ/m{sup 2} and root mean square error of 0.131 MJ/m{sup 2}. Overall, the artificial neural networks model predicted with an accuracy of 0.1% of the mean absolute percentage error. (author)

  12. Solar radiation models - review

    Directory of Open Access Journals (Sweden)

    M. Jamil Ahmad, G.N. Tiwari

    2010-05-01

    Full Text Available In the design and study of solar energy, information on solar radiation and its components at a given location is very essential. Solar radiation data are required by solar engineers, architects, agriculturists and hydrologists for many applications such as solar heating, cooking, drying and interior illumination of buildings. For this purpose, in the past, several empirical correlations have been developed in order to estimate the solar radiation around the world. The main objective of this study is to review the global solar radiation models available in the literature. There are several formulae which relate global radiation to other climatic parameters such as sunshine hours, relative humidity and maximum temperature. The most commonly used parameter for estimating global solar radiation is sunshine duration. Sunshine duration can be easily and reliably measured and data are widely available.

  13. Simulation of solar radiation during a total solar eclipse: a challenge for radiative transfer

    Directory of Open Access Journals (Sweden)

    C. Emde

    2007-01-01

    Full Text Available A solar eclipse is a rare but spectacular natural phenomenon and furthermore it is a challenge for radiative transfer modeling. Whereas a simple one-dimensional radiative transfer model with reduced solar irradiance at the top of the atmosphere can be used to calculate the brightness during partial eclipses a much more sophisticated model is required to calculate the brightness (i.e. the diffuse radiation during the total eclipse. The reason is that radiation reaching a detector in the shadow gets there exclusively by horizontal (three-dimensional transport of photons in a spherical shell atmosphere. In this study the first accurate simulations are presented examplified by the solar eclipse at 29 March 2006. Using a backward Monte Carlo model we calculated the diffuse radiation in the umbra and simulated the changing colors of the sky. Radiance and irradiance are decreased by 3 to 4 orders of magnitude, depending on wavelength. We found that aerosol has a comparatively small impact on the radiation in the umbra. We also estimated the contribution of the solar corona to the radiation under the umbra and found that it is negligible compared to the diffuse solar radiation in most parts of the spectrum. Spectrally resolved measurements in the umbra are not yet available. They are challenging due to the low intensity and therefore need careful planning. The new model may be used to support measurements during future solar eclipses.

  14. Models of Solar Irradiance Variations: Current Status

    Indian Academy of Sciences (India)

    Natalie A. Krivova; Sami K. Solanki

    2008-03-01

    Regular monitoring of solar irradiance has been carried out since 1978 to show that solar total and spectral irradiance varies at different time scales. Whereas variations on time scales of minutes to hours are due to solar oscillations and granulation, variations on longer time scales are driven by the evolution of the solar surface magnetic field. Here the most recent advances in modelling of solar irradiance variations on time scales longer than a day are briefly reviewed.

  15. Influences of atmospheric conditions and air mass on the ratio of ultraviolet to total solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Riordan, C.J.; Hulstrom, R.L.; Myers, D.R.

    1990-08-01

    The technology to detoxify hazardous wastes using ultraviolet (UV) solar radiation is being investigated by the DOE/SERI Solar Thermal Technology Program. One of the elements of the technology evaluation is the assessment and characterization of UV solar radiation resources available for detoxification processes. This report describes the major atmospheric variables that determine the amount of UV solar radiation at the earth's surface, and how the ratio of UV-to-total solar radiation varies with atmospheric conditions. These ratios are calculated from broadband and spectral solar radiation measurements acquired at SERI, and obtained from the literature on modeled and measured UV solar radiation. The following sections discuss the atmospheric effects on UV solar radiation and provide UV-to-total solar radiation ratios from published studies, as well as measured values from SERI's data. A summary and conclusions are also given.

  16. NOAA Climate Data Record (CDR) of Total Solar Irradiance (TSI), NRLTSI Version 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Climate Data Record (CDR) contains total solar irradiance (TSI) as a function of time created with the Naval Research Laboratory model for spectral and total...

  17. The influence of solar system oscillation on the variability of the total solar irradiance

    Science.gov (United States)

    Yndestad, Harald; Solheim, Jan-Erik

    2017-02-01

    Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation variability and expected long-term climate variation, whereas a non-deterministic variability can only explain the past. This study of solar variability is based on an analysis of two TSI data series, one since 1700 A.D. and one since 1000 A.D.; a sunspot data series since 1610 A.D.; and a solar orbit data series from 1000 A.D. The study is based on a wavelet spectrum analysis. First, the TSI data series are transformed into a wavelet spectrum. Then, the wavelet spectrum is transformed into an autocorrelation spectrum to identify stationary, subharmonic and coincidence periods in the TSI variability. The results indicate that the TSI and sunspot data series have periodic cycles that are correlated with the oscillations of the solar position relative to the barycenter of the solar system, which is controlled by gravity force variations from the large planets Jupiter, Saturn, Uranus and Neptune. A possible explanation for solar activity variations is forced oscillations between the large planets and the solar dynamo. We find that a stationary component of the solar variability is controlled by the 12-year Jupiter period and the 84-year Uranus period with subharmonics. For TSI and sunspot variations, we find stationary periods related to the 84-year Uranus period. Deterministic models based on the stationary periods confirm the results through a close relation to known long solar minima since 1000 A.D. and suggest a modern maximum period from 1940 to 2015. The model computes a new Dalton-type sunspot minimum from approximately 2025 to 2050 and a new Dalton-type period TSI minimum from approximately 2040 to 2065.

  18. Modeling of solar polygeneration plant

    Science.gov (United States)

    Leiva, Roberto; Escobar, Rodrigo; Cardemil, José

    2017-06-01

    In this work, a exergoeconomic analysis of the joint production of electricity, fresh water, cooling and process heat for a simulated concentrated solar power (CSP) based on parabolic trough collector (PTC) with thermal energy storage (TES) and backup energy system (BS), a multi-effect distillation (MED) module, a refrigeration absorption module, and process heat module is carried out. Polygeneration plant is simulated in northern Chile in Crucero with a yearly total DNI of 3,389 kWh/m2/year. The methodology includes designing and modeling a polygeneration plant and applying exergoeconomic evaluations and calculating levelized cost. Solar polygeneration plant is simulated hourly, in a typical meteorological year, for different solar multiple and hour of storage. This study reveals that the total exergy cost rate of products (sum of exergy cost rate of electricity, water, cooling and heat process) is an alternative method to optimize a solar polygeneration plant.

  19. Solar insolation model

    Science.gov (United States)

    Smith, J. H.

    1980-01-01

    Computer program SOLINS helps engineers with relatively complex task of choosing best orientation of fixed flat-plate solar collectors for local conditions. Program models average hourly solar insolation on fixed but arbitrarily-oriented surface. Consideration is given to problems of array spacing, shadowing, and use of augmentation reflectors to increase insolation at collector surface.

  20. Correlation of total, diffuse, and direct solar radiation

    Science.gov (United States)

    Buyco, E. H.; Namkoong, D.

    1977-01-01

    Present requirements for realistic solar energy system evaluations necessitate a comprehensive body of solar-radition data. The data should include both diffuse and direct solar radiation as well as their total on an hourly (or shorter) basis. In general, however, only the total solar radiation values were recorded. This report presents a correlation that relates the diffuse component of an hourly total solar radiation value to the total radiation ratio of the maximum value attainable. The data used were taken at the Blue Hill Observatory in Milton, Massachusetts, for the period 1952. The relation - in the form of the data plots - can be used in situations in which only the hourly total radiation data are available but the diffuse component is desired.

  1. Commercial applications of solar total energy systems. Volume 4. Appendices. Final report. [Solar Total Energy System Evaluation Program (STESEP) code

    Energy Technology Data Exchange (ETDEWEB)

    Boobar, M.G.; McFarland, B.L.; Nalbandian, S.J.; Willcox, W.W.; French, E.P.; Smith, K.E.

    1978-07-01

    A methodology has been developed by Atomics International under contract to the Department of Energy to define the applicability of solar total energy systems (STES) to the commercial sector (e.g., retail stores, shopping centers, offices, etc.) in the United States. Candidate STES concepts were selected to provide on-site power generation capability, as well as thermal energy for both heating and cooling applications. Each concept was evaluated on the basis of its cost effectiveness (i.e., as compared to other concepts) and its ability to ultimately penetrate and capture a significant segment of this market, thereby resulting in a saving of fossil fuel resources. This volume contains the appendices. Topics include deterministic insolation model computer code; building energy usage data; computer simulation programs for building energy demand analysis; model buildings for STES evaluation; Solar Total Energy System Evaluation Program (STESEP) computer code; transient simulation of STES concept; solar data tape analysis; program listings and sample output for use with TRNSYS; transient simulation, and financial parameters sensitivities. (WHK)

  2. The new climate data record of total and spectral solar irradiance: Current progress and future steps

    Science.gov (United States)

    Coddington, Odele; Lean, Judith; Rottman, Gary; Pilewskie, Peter; Snow, Martin; Lindholm, Doug

    2016-04-01

    We present a climate data record of Total Solar Irradiance (TSI) and Solar Spectral Irradiance (SSI), with associated time and wavelength dependent uncertainties, from 1610 to the present. The data record was developed jointly by the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder and the Naval Research Laboratory (NRL) as part of the National Oceanographic and Atmospheric Administration's (NOAA) National Centers for Environmental Information (NCEI) Climate Data Record (CDR) Program, where the data record, source code, and supporting documentation are archived. TSI and SSI are constructed from models that determine the changes from quiet Sun conditions arising from bright faculae and dark sunspots on the solar disk using linear regression of proxies of solar magnetic activity with observations from the SOlar Radiation and Climate Experiment (SORCE) Total Irradiance Monitor (TIM), Spectral Irradiance Monitor (SIM), and SOlar Stellar Irradiance Comparison Experiment (SOLSTICE). We show that TSI can be separately modeled to within TIM's measurement accuracy from solar rotational to solar cycle time scales and we assume that SSI measurements are reliable on solar rotational time scales. We discuss the model formulation, uncertainty estimates, and operational implementation and present comparisons of the modeled TSI and SSI with the measurement record and with other solar irradiance models. We also discuss ongoing work to assess the sensitivity of the modeled irradiances to model assumptions, namely, the scaling of solar variability from rotational-to-cycle time scales and the representation of the sunspot darkening index.

  3. Reconstruction of total solar irradiance 1974-2009

    CERN Document Server

    Ball, W T; Krivova, N A; Solanki, S; Wenzler, T; Mortlock, D J; Jaffe, A H

    2012-01-01

    Context: The study of variations in total solar irradiance (TSI) is important for understanding how the Sun affects the Earth's climate. Aims: Full-disk continuum images and magnetograms are now available for three full solar cycles. We investigate how modelled TSI compares with direct observations by building a consistent modelled TSI dataset. The model, based only on changes in the photospheric magnetic flux can then be tested on rotational, cyclical and secular timescales. Methods: We use Kitt Peak and SoHO/MDI continuum images and magnetograms in the SATIRE-S model to reconstruct TSI over cycles 21-23. To maximise independence from TSI composites, SORCE/TIM TSI data are used to fix the one free parameter of the model. We compare and combine the separate data sources for the model to estimate an uncertainty on the reconstruction and prevent any additional free parameters entering the model. Results: The reconstruction supports the PMOD composite as being the best historical record of TSI observations, alth...

  4. Aerosol Lidar observations and model calculations of the Planetary Boundary Layer evolution over Greece, during the March 2006 Total Solar Eclipse

    Directory of Open Access Journals (Sweden)

    V. Amiridis

    2007-12-01

    Full Text Available An investigation of the Planetary Boundary Layer (PBL height evolution over Greece, during the solar eclipse of 29 March 2006, is presented. Ground based observations were carried out using lidar detection and ranging devices and ground meteorological instruments, to estimate the height of the mixing layer (ML before, during and after the solar eclipse in northern and southern parts of Greece exhibiting different sun obscuration. Data demonstrate that the solar eclipse has induced a decrease of the PBL height, indicating a suppression of turbulence activity similar to that during the sunset hours. The changes in PBL height were associated with a very shallow entrainment zone, indicating a significant weakening of the penetrative convection. Heat transfer was confined to a thinner layer above the ground. The thickness of the entrainment zone exhibited its minimum during the maximum of the eclipse, demonstrative of turbulence mechanisms suppression at that time. Model estimations of the PBL evolution were additionally conducted using the Comprehensive Air Quality Model with extensions (CAMx coupled with the Weather Research and Forecasting model (WRF. Model-diagnosed PBL height decrease during the solar eclipse due to vertical transport decay, in agreement with the experimental findings; vertical profiles of atmospheric particles and gaseous species showed an important vertical mixing attenuation.

  5. Aerosol lidar observations and model calculations of the planetary boundary layer evolution over Greece, during the March 2006 total solar eclipse

    Directory of Open Access Journals (Sweden)

    V. Amiridis

    2007-09-01

    Full Text Available An investigation of the Planetary Boundary Layer (PBL height evolution over Greece, during the solar eclipse of 29 March 2006, is presented. Ground based observations were carried out using lidar detection and ranging devices (Lidars and ground meteorological instruments, to estimate the height of the Mixing Layer (ML before, during and after the solar eclipse in Northern and Southern parts of Greece exhibiting different sun obscuration. Data demonstrate that the solar eclipse has induced a decrease of the PBL height, indicating a suppression of turbulence activity similar to that during the sunset hours. The changes in PBL height were associated with a very shallow entrainment zone, indicating a significant weakening of the penetrative convection. Heat transfer was confined to a thinner layer above ground. The thickness of the entrainment zone exhibited its minimum during the maximum of the eclipse, demonstrative of turbulence mechanisms suppression at that time. Model estimations of the PBL evolution were additionally conducted using the Comprehensive Air Quality Model with extensions (CAMx coupled with the Weather Research and Forecasting model (WRF. Model diagnosed PBL height decrease during the solar eclipse due to vertical transport decay, in agreement with the experimental findings; vertical profiles of atmospheric particles and gaseous species showed an important vertical mixing attenuation.

  6. Towards a long-term record of solar total and spectral irradiance

    CERN Document Server

    Krivova, N A; Unruh, Y C; 10.1016/j.jastp.2009.11.013

    2009-01-01

    The variation of total solar irradiance (TSI) has been measured since 1978 and that of the spectral irradiance for an even shorter amount of time. Semi-empirical models are now available that reproduce over 80% of the measured irradiance variations. An extension of these models into the more distant past is needed in order to serve as input to climate simulations. Here we review our most recent efforts to model solar total and spectral irradiance on time scales from days to centuries and even longer. Solar spectral irradiance has been reconstructed since 1947. Reconstruction of solar total irradiance goes back to 1610 and suggests a value of about 1-1.5 Wm$^{-2}$ for the increase in the cycle-averaged TSI since the end of the Maunder minimum, which is significantly lower than previously assumed but agrees with other modern models. First steps have also been made towards reconstructions of solar total and spectral irradiance on time scales of millennia.

  7. Modeling of Solar Concentrators

    Science.gov (United States)

    Rockey, D. E.

    1984-01-01

    Algorithm developed for predicting power output, uniformity of intensity and operating temperature of concentrator-enhanced photovoltaic solar cell arrays. Optimum values for parameters such as reflector geometry found prior to constructing scale models for testing.

  8. Boundary layer photochemistry during a total solar eclipse

    Directory of Open Access Journals (Sweden)

    Peter Fabian

    2001-05-01

    Full Text Available Simultaneous measurements of radiation, photolysis frequencies, O3, CO, OH, PAN and NOx species were carried out in the boundary layer, along with pertinent meteorological parameters, under total solar eclipse conditions. This experiment performed at about 34 solar zenith angle and noontime conditions thus provided a case study about the interactions between radiation and photochemistry under fast ''day-night'' and ''night-day'' transitions, at high solar elevation. The results reveal a close correlation of photolysis frequencies jO(1D and jNO2with the UV radiation flux. All three parameters show, due to the decreasing fraction of direct radiation at shorter wavelengths, much weaker cloud shading effects than global solar radiation. NO and OH concentrations decrease to essentially zero during totality. Subsequently, NO and OH concentrations increased almost symmetrically to their decrease preceding totality. The NO/NO2 ratio was proportional to jNO2over 30 min before and after totality indicating that the partitioning of NOx species is determined by jNO2. Simple box model simulations show the effect of reduced solar radiation on the photochemical production of O3 and PAN. WÄhrend der totalen Sonnenfinsternis am 11. August 1999 wurden simultane und kontinuierliche Messungen von O3, CO, OH, PAN and NOx, Strahlung, Photolysefrequenzen und relevanten meteorologischen Parametern durchgefÜhrt. Dieses Experiment, durchgefÜhrt etwa am Mittag, bei 34 Zenithwinkel der Sonne, ermöglichte die Untersuchung der Interaktion von Strahlung und Photochemie fÜr schnelle Tag-Nacht und Nacht-Tag-ÜbergÄnge bei hohem Sonnenstand. Die Ergebnisse zeigen eine enge Korrelation der Photolysefrequenzen jO(1D und jNO2 mit dem UV-Strahlungsfluss. Alle drei Parameter zeigen, wegen des abnehmenden Anteils direkter Sonnenstrahlung bei kurzen WellenlÄngen, erheblich geringere AbschwÄchung durch Wolken als die Globalstrahlung. NO und OH gehen wÄhrend der

  9. Magnitudes and Timescales of Total Solar Irradiance Variability

    CERN Document Server

    Kopp, Greg

    2016-01-01

    The Sun's net radiative output varies on timescales of minutes to gigayears. Direct measurements of the total solar irradiance (TSI) show changes in the spatially- and spectrally-integrated radiant energy on timescales as short as minutes to as long as a solar cycle. Variations of ~0.01 % over a few minutes are caused by the ever-present superposition of convection and oscillations with very large solar flares on rare occasion causing slightly-larger measureable signals. On timescales of days to weeks, changing photospheric magnetic activity affects solar brightness at the ~0.1 % level. The 11-year solar cycle shows variations of comparable magnitude with irradiances peaking near solar maximum. Secular variations are more difficult to discern, being limited by instrument stability and the relatively short duration of the space-borne record. Historical reconstructions of the Sun's irradiance based on indicators of solar-surface magnetic activity, such as sunspots, faculae, and cosmogenic isotope records, sugge...

  10. Submillimeter solar limb profiles determined from observations of the total solar eclipse of 1988 March 18

    Science.gov (United States)

    Roellig, T. L.; Becklin, E. E.; Jefferies, J. T.; Kopp, G. A.; Lindsey, C. A.; Orrall, F. Q.; Werner, M. W.

    1991-01-01

    Observations were made of the extreme solar limb in six far-infrared wavelength bands ranging from 30 to 670 micron using the Kuiper Airborne Observatory during the total eclipse of the sun on 1988 March 18. By observations of the occultation of the solar limb by the moon, it was possible to obtain a spatial resolution of 0.5 arcsec normal to the limb. The solar limb was found to be extended with respect to the visible limb at all of these wavelengths, with the extension increasing with wavelength. Limb brightening was observed to increase slightly with increasing wavelength, and no sign of a sharp emission spike at the extreme limb was found at any of these wavelengths. The observations can be well fitted by a chromospheric model incorporating cool dense spicules in the lower chromosphere.

  11. Total solar eclipse of 3 November 1994

    Science.gov (United States)

    Espenak, Fred; Anderson, Jay

    1993-01-01

    A total eclipse of the Sun will be visible from the southern half of the Western Hemisphere on 3 November 1994. The path of the Moon's shadow passes through Peru, Chile, Bolivia, Paraguay, and Brazil. Detailed predictions for this event are presented and include tables of geographic coordinates of the path of totality, local circumstances for hundreds of cities, maps of the path of total and partial eclipse, weather prospects, and the lunar limb profile.

  12. The Signature of Flares in VIRGO Total Solar Irradiance Measurements

    CERN Document Server

    Quesnel, A; Fleck, B; Froelich, C; Hudson, H S

    2010-01-01

    We use Total Solar Irradiance (TSI) measurements from the VIRGO (Variability of solar IRradiance and Gravity Oscillations) instrument on board SOHO to obtain preliminary estimates of the mean total radiative energy emitted by X-class solar flares. The basic tool is that of summed-epoch analysis, which has also enabled us to detect and partially characterize systematic errors present in the basic data. We describe these errors, which significantly degrade the photometry at high frequencies. We find the ratio of GOES 1-8\\{AA} luminosity to total bolometric luminosity to be of order 0.01.

  13. Magnitudes and timescales of total solar irradiance variability

    Science.gov (United States)

    Kopp, Greg

    2016-07-01

    The Sun's net radiative output varies on timescales of minutes to gigayears. Direct measurements of the total solar irradiance (TSI) show changes in the spatially- and spectrally-integrated radiant energy on timescales as short as minutes to as long as a solar cycle. Variations of ~0.01% over a few minutes are caused by the ever-present superposition of convection and oscillations with very large solar flares on rare occasion causing slightly-larger measurable signals. On timescales of days to weeks, changing photospheric magnetic activity affects solar brightness at the ~0.1% level. The 11-year solar cycle shows variations of comparable magnitude with irradiances peaking near solar maximum. Secular variations are more difficult to discern, being limited by instrument stability and the relatively short duration of the space-borne record. Historical reconstructions of the Sun's irradiance based on indicators of solar-surface magnetic activity, such as sunspots, faculae, and cosmogenic isotope records, suggest solar brightness changes over decades to millennia, although the magnitudes of these variations have high uncertainties due to the indirect historical records on which they rely. Stellar evolution affects yet longer timescales and is responsible for the greatest solar variabilities. In this manuscript I summarize the Sun's variability magnitudes over different temporal regimes and discuss the irradiance record's relevance for solar and climate studies as well as for detections of exo-solar planets transiting Sun-like stars.

  14. Total solar eclipse of 1995 October 24

    Science.gov (United States)

    Espenak, Fred; Anderson, Jay

    1994-01-01

    A total eclipse of the sun will be visible from Asia and the Pacific Ocean on 24 Oct. 1995. The path of the moon's shadow begins in the Middle East and sweeps across India, Southeast Asia, and the waters of the Indonesian archipelago before ending at sunset in the Pacific. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality.

  15. The total solar eclipse of March 2006: overview

    Directory of Open Access Journals (Sweden)

    A. Karamanos

    2008-09-01

    Full Text Available This paper provides the overview of an integrated, multi-disciplinary effort to study the effects of the 29 March 2006 total solar eclipse on the environment, with special focus on the atmosphere. The eclipse has been visible over the Eastern Mediterranean, and on this occasion several research and academic institutes organised co-ordinated experimental campaigns, at different distances from eclipse totality and at various environments in terms of air quality. Detailed results and findings are presented in a number of component scientific papers included in a Special Issue of Atmospheric Chemistry and Physics. The effects of the eclipse on meteorological parameters, though very clear, were shown to be controlled by local factors rather than the eclipse magnitudes, and the turbulence activity near surface was suppressed causing a decrease in the Planetary Boundary Layer. In addition to the above, the decrease in solar radiation has caused change to the photochemistry of the atmosphere, with night time chemistry dominating. The abrupt "switch off" of the sun, induced changes also in the ionosphere (140 up to 220 km and the stratosphere. In the ionosphere, both photochemistry and dynamics resulted to changes in the reflection heights and the electron concentrations. Among the most important scientific findings from the experiments undertaken has been the experimental proof of eclipse induced thermal fluctuations in the ozone layer (Gravity Waves, due to the supersonic movement of the moon's shadow, for the first time with simultaneous measurements at three altitudes namely the troposphere, the stratosphere and the ionosphere. Within the challenging topics of the experiments has been the investigation of eclipse impacts on ecosystems (field crops and marine plankton. The rare event of a total solar eclipse provided the opportunity to evaluate 1 dimensional (1-D and three dimensional (3-D radiative transfer (in the atmosphere and underwater

  16. Total Solar Eclipse of 1997 March 9

    Science.gov (United States)

    Espenak, Fred; Anderson, Jay

    1995-01-01

    A total eclipse of the Sun will be visible from Asia and the Pacific Ocean on 1997 March 9. The path of the Moon's umbral shadow begins in eastern Kazakhstan and travels through Mongolia and eastern Siberia, where it swings northward to end at sunset in the Arctic Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern Asia, the northern Pacific, and the northwest corner of North America. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 280 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

  17. Total Solar Eclipse of 2001 June 21

    Science.gov (United States)

    Espenak, Fred; Anderson, Jay

    1999-01-01

    On 2001 June 21, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and Madagascar, and ends at sunset in the Indian Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern South America and the southern two thirds of Africa. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

  18. Total Solar Eclipse of 2002 December 04

    Science.gov (United States)

    Espenak, Fred; Anderson, Jay

    2001-01-01

    On 2002 December 04, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and the Indian Ocean, and ends at sunset in southern Australia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the southern two thirds of Africa, Antarctica, Indian Ocean and Australia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

  19. Total Solar Eclipse of 1999 August 11

    Science.gov (United States)

    Espenak, Fred; Anderson, Jay

    1997-01-01

    On 1999 August 11, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Eastern Hemisphere. The path of the Moon's umbral shadow begins in the Atlantic and crosses central Europe, the Middle East, and India, where it ends at sunset in the Bay of Bengal. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, all of Europe, northern Africa, and the western half of Asia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 1400 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

  20. Total Solar Eclipse of 2008 August 01

    Science.gov (United States)

    Espenak, F.; Anderson, J.

    2007-01-01

    On 2008 August 01, a total eclipse of the Sun is visible from within a narrow corridor that traverses half the Earth. The path of the Moon's umbral shadow begins in northern Canada and extends across Greenland, the Arctic, central Russia, Mongolia, and China. A partial eclipse is seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, most of Europe and Asia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 308 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

  1. Total Solar Eclipse of 2006 March 29

    Science.gov (United States)

    Espenak, F.; Anderson, J.

    2004-01-01

    On 2006 March 29, a total eclipse of the Sun will be visible from within a narrow corridor which traverses half the Earth. The path of the Moon's umbral shadow begins in Brazil and extends across the Atlantic, northern Africa, and central Asia where it ends at sunset in western Mongolia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the northern two thirds of Africa, Europe, and central Asia.Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

  2. Coronal structure and flattening during total solar eclipse 2006

    Directory of Open Access Journals (Sweden)

    A.A. Galal

    2012-12-01

    Full Text Available On the basis of well resolved observations of the solar corona taken at Salloum N-W of Egypt during the total solar eclipse of 2006 “the descending phase of solar cycle 23”, some aspects of the physics of the corona have been studied up to several solar radii. The magnetic structures of the white light corona were studied. The flattening coefficient e characterizes the shape of the isophotes of the whit-light corona and computed as a function of the distance from the disk center. The flattening index e during solar total eclipse 2006 was found to be 0.158. This result is in a good agreement with previous published results.

  3. Anticipation of total solar eclipse and suicide incidence.

    Science.gov (United States)

    Voracek, Martin; Rancāns, Elmārs; Vintilă, Mona; Fisher, Maryanne

    2004-09-01

    Around the total solar eclipse of August 11 1999, suicide incidence decreased in Timiş county, Romania, a region crossed by the path of totality and subject to eclipse-trekking, whereas no such decrease was observed in Latvia, where only a partial eclipse was observed. Collective anticipation of a positive event could have a preventive effect on suicide incidence.

  4. Preparing for and Observing the 2017 Total Solar Eclipse

    OpenAIRE

    2015-01-01

    I discuss ongoing plans and discussions for EPO and scientific observing of the 21 August 2017 total solar eclipse. I discuss aspects of EPO based on my experiences at the 60 solar eclipses I have seen. I share cloud statistics along the eclipse path compiled by Jay Anderson, the foremost eclipse meteorologist. I show some sample observations of composite imagery, of spectra, and of terrestrial temperature changes based on observations of recent eclipses, including 2012 from Australia and 201...

  5. SORCE Level 3 Total Solar Irradiance 6-Hour Average V016

    Data.gov (United States)

    National Aeronautics and Space Administration — The Total Solar Irradiance (TSI) data set SOR3TSI6 contains the total solar irradiance (a.k.a solar constant) data collected by the Total Irradiance Monitor (TIM)...

  6. new model for solar radiation estimation from measured air ...

    African Journals Online (AJOL)

    HOD

    Nigerian Meteorological Agency (NIMET) were used as inputs to the ANFIS model and monthly mean global solar radiation was ... models were used to predict solar radiation in Nigeria by. [12-15]. .... calculate them as total output [32] and [34].

  7. Solar Backscatter UV (SBUV total ozone and profile algorithm

    Directory of Open Access Journals (Sweden)

    P. K. Bhartia

    2013-10-01

    Full Text Available We describe the algorithm that has been applied to develop a 42 yr record of total ozone and ozone profiles from eight Solar Backscatter UV (SBUV instruments launched on NASA and NOAA satellites since April 1970. The Version 8 (V8 algorithm was released more than a decade ago and has been in use since then at NOAA to produce their operational ozone products. The current algorithm (V8.6 is basically the same as V8, except for updates to instrument calibration, incorporation of new ozone absorption cross-sections, and new ozone and cloud height climatologies. Since the V8 algorithm has been optimized for deriving monthly zonal mean (MZM anomalies for ozone assessment and model comparisons, our emphasis in this paper is primarily on characterizing the sources of errors that are relevant for such studies. When data are analyzed this way the effect of some errors, such as vertical smoothing of short-term variability, and noise due to clouds and aerosols diminish in importance, while the importance of others, such as errors due to vertical smoothing of the quasi-biennial oscillation (QBO and other periodic and aperiodic variations, become more important. With V8.6 zonal mean data we now provide smoothing kernels that can be used to compare anomalies in SBUV profile and partial ozone columns with models. In this paper we show how to use these kernels to compare SBUV data with Microwave Limb Sounder (MLS ozone profiles. These kernels are particularly useful for comparisons in the lower stratosphere where SBUV profiles have poor vertical resolution but partial column ozone values have high accuracy. We also provide our best estimate of the smoothing errors associated with SBUV MZM profiles. Since smoothing errors are the largest source of uncertainty in these profiles, they can be treated as error bars in deriving interannual variability and trends using SBUV data and for comparing with other measurements. In the V8 and V8.6 algorithms we derive total

  8. Gravity anomaly during the Mohe total solar eclipse

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    By using a high-precision LaCoste-Romberg (1)-122#) gravimeter, continuous and precise measurements were carried out during the March 9, 1997 total solar eclipse in the Mohe region in Northeast China. The gravity variations were digitally recorded during the total solar eclipse so as to investigate the possible anomaly of the sun and the moon's gravitational fields on the earth. After the careful processing and analysis of the observed data, no significant anomaly during the very solar eclipse has been found. Howmetrical decrease of about 6- 7 μGal at the first contact and the last contact. This is the anomaly phenomenon observed and reported for the first time in the literature. This note presents some analyses and discussions.

  9. Analysis and modeling of solar irradiance variations

    CERN Document Server

    Yeo, K L

    2014-01-01

    A prominent manifestation of the solar dynamo is the 11-year activity cycle, evident in indicators of solar activity, including solar irradiance. Although a relationship between solar activity and the brightness of the Sun had long been suspected, it was only directly observed after regular satellite measurements became available with the launch of Nimbus-7 in 1978. The measurement of solar irradiance from space is accompanied by the development of models aimed at describing the apparent variability by the intensity excess/deficit effected by magnetic structures in the photosphere. The more sophisticated models, termed semi-empirical, rely on the intensity spectra of photospheric magnetic structures generated with radiative transfer codes from semi-empirical model atmospheres. An established example of such models is SATIRE-S (Spectral And Total Irradiance REconstruction for the Satellite era). One key limitation of current semi-empirical models is the fact that the radiant properties of network and faculae a...

  10. Total and Spectral Solar Irradiance Sensor (TSIS) Project Overview

    Science.gov (United States)

    Carlisle, Candace; Wedge, Ronnice; Wu, Dong; Stello, Harry; Robinson, Renee

    2015-01-01

    The main objective of the Total and Spectral solar Irradiance Sensor (TSIS) is to acquire measurements to determine the direct and indirect effects of solar radiation on climate. TSIS total solar irradiance measurements will extend a 37-year long uninterrupted measurement record of incoming solar radiation, the dominant energy source driving the Earths climate and the most precise indicator of changes in the Suns energy output. TSIS solar spectral irradiance measurements will determine the regions of the Earths multi-layered atmosphere that are affected by solar variability, from which the solar forcing mechanisms causing changes in climate can be quantified. TSIS includes two instruments: the Total Irradiance Monitor (TIM) and the Spectral Irradiance Monitor (SIM), integrated into a single payload. The TSIS TIM and SIM instruments are upgraded versions of the two instruments that are flying on the Solar Radiation and Climate Experiment (SORCE) mission launched in January 2003. TSIS was originally planned for the nadir-pointing National Polar-orbiting Operational Environmental Satellite System (NPOESS) spacecraft. The TSIS instrument passed a Critical Design Review (CDR) for NPOESS in December 2009. In 2010, TSIS was re-planned for the Joint Polar Satellite System (JPSS) Polar Free Flyer (PFF). The TSIS TIM, SIM, and associated electronics were built, tested, and successfully completed pre-ship review as of December 2013.In early 2014, NOAA and NASA agreed to fly TSIS on the International Space Station (ISS). In the FY16 Presidents Budget, NASA assumes responsibility for the TSIS mission on ISS. The TSIS project includes requirements, interface, design, build and test of the TSIS payload, including an updated pointing system, for accommodation on the ISS. It takes advantage of the prior development of the TSIS sensors and electronics. The International Space Station (ISS) program contributions include launch services and robotic installation of the TSIS payload

  11. Total solar eclipses and how to observe them

    CERN Document Server

    Mobberley, Martin

    2007-01-01

    This is the ultimate, easy-to-read guide for "eclipse-chasers" which includes everything an eclipse chaser needs. It provides a checklist of where to go to see total solar eclipses, for the next 15 years, and includes travel details.

  12. First Results from the August 21, 2017, Total Solar Eclipse

    Science.gov (United States)

    Pasachoff, Jay M.

    2017-08-01

    I report on the observations planned and, weather permitting, made from our site in Salem, Oregon, at the August 21, 2017, total solar eclipse. I also give a first report on collaborators' successes, including Megamovie and simultaneous space observations. We also describe our participation in PBS's NOVA on the eclipse that was to be aired on public television on eclipse night. Our eclipse expedition is supported in large part by grants from the Solar Terrestrial Program of the Atmospheric Sciences Division of NSF and by the Committee for Research and Exploration of the National Geographic Society.

  13. Educating the Public about the 2017 Total Solar Eclipse

    Science.gov (United States)

    Pasachoff, Jay M.

    2017-01-01

    On behalf of the International Astronomical Union's Working Group on Solar Eclipses, I have long worked to bring knowledge about eclipses and how to observe the safely to the people of the various countries from which partial, annular, or total solar eclipses are visible. In 2017, we have first a chance to educate the people of South America on the occasion of the February 26 annular eclipse through southern Chile and Argentina that is partial throughout almost the entire continent (and an eclipse workshop will be held February 22-24 in Esquel, Argentina: http://sion.frm.utn.edu.ar/WDEAII) and then a chance to educate the 300 million people of the United States and others in adjacent countries as far south as northern South America about the glories of totality and how to observe partial phases. Our website, a compendium of links to information about maps, safe observing, science, and more is at http://eclipses.info. We link to important mapping sites at EclipseWise.com, GreatAmericanEclipse.com, and http://xjubier.free.fr/en/site_pages/solar_eclipses/xSE_GoogleMap3.php?Ecl=+20170821&Acc=2&Umb=1&Lmt=1&Mag=1&Max=1, and information about cloudiness statistics at http://eclipsophile.com, as well as simulation sites at https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4314 and http://eyes.jpl.nasa.gov. The American Astronomical Society's task force on the 2017 eclipse has a website at http://eclipse.aas.org. We are working to disseminate accurate information about how and why to observe the total solar eclipse, trying among other things to head off common misinformation about the hazards of looking at the sun at eclipses or otherwise. About 12 million Americans live within the 70-mile-wide band of totality, and we encourage others to travel into it, trying to make clear the difference between even a 99% partial eclipse and a total eclipse, with its glorious Baily's beads, diamond rings, and totality that on this occasion lasts between 2 minutes and 2 minutes 40 seconds

  14. Towards a long-term record of solar total and spectral irradiance

    OpenAIRE

    Krivova, N. A.; Solanki, S. K.; Unruh, Y. C.

    2009-01-01

    The variation of total solar irradiance (TSI) has been measured since 1978 and that of the spectral irradiance for an even shorter amount of time. Semi-empirical models are now available that reproduce over 80% of the measured irradiance variations. An extension of these models into the more distant past is needed in order to serve as input to climate simulations. Here we review our most recent efforts to model solar total and spectral irradiance on time scales from days to centuries and even...

  15. The solar corona through the sunspot cycle: preparing for the August 21, 2017, total solar eclipse

    Science.gov (United States)

    Pasachoff, Jay M.; Seaton, Daniel; Rusin, Vojtech

    2017-01-01

    We discuss the evolution of the solar corona as seen at eclipses through the solar-activity cycle. In particular, we discuss the variations of the overall shape of the corona through the relative proportions of coronal streamers at equatorial and other latitudes vs. polar plumes. We analyze the two coronal mass ejections that we observed from Gabon at the 2013 total solar eclipse and how they apparently arose from polar crown filaments, one at each pole. We describe the change in the Ludendorff flattening index from solar maximum in one hemisphere as of the 2013 eclipse through the 2015 totality's corona we observed from Svalbard and, with diminishing sunspot and other magnetic activity in each hemisphere, through the 2016 corona we observed from Ternate, Indonesia.We discuss our observational plans for the August 21, 2017, total solar eclipse from our main site in Salem, Oregon, and subsidiary sites in Madras, OR; Carbondale, IL; and elsewhere, our main site chosen largely by its favorable rating in cloudiness statistics. We discuss the overlapping role of simultaneous spacecraft observations, including those expected not only from NASA's SDO, ESA's SWAP on PROBA2, and NRL/NASA/ESA's LASCO on SOHO but also from the new SUVI (Solar Ultraviolet Imager) aboard NOAA's GOES-R satellite, scheduled as of this writing to have been launched by the time of this January 2017 meeting.Our research on the 2013 and 2015 total solar eclipses was supported by grants from the Committee for Research and Exploration of the National Geographic Society (NG-CRE). Our research on the 2017 total solar eclipse is supported by both NG-CRE and the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation.

  16. The Total Solar Irradiance, UV Emission and Magnetic Flux during the Last Solar Cycle Minimum

    Directory of Open Access Journals (Sweden)

    E. E. Benevolenskaya

    2013-01-01

    Full Text Available We have analyzed the total solar irradiance (TSI and the spectral solar irradiance as ultraviolet emission (UV in the wavelength range 115–180 nm, observed with the instruments TIM and SOLSTICE within the framework of SORCE (the solar radiation and climate experiment during the long solar minimum between the 23rd and 24th cycles. The wavelet analysis reveals an increase in the magnetic flux in the latitudinal zone of the sunspot activity, accompanied with an increase in the TSI and UV on the surface rotation timescales of solar activity complexes. In-phase coherent structures between the midlatitude magnetic flux and TSI/UV appear when the long-lived complexes of the solar activity are present. These complexes, which are related to long-lived sources of magnetic fields under the photosphere, are maintained by magnetic fluxes reappearing in the same longitudinal regions. During the deep solar minimum (the period of the absence of sunspots, a coherent structure has been found, in which the phase between the integrated midlatitude magnetic flux is ahead of the total solar irradiance on the timescales of the surface rotation.

  17. WHAT CAUSES THE INTER-SOLAR-CYCLE VARIATION OF TOTAL SOLAR IRRADIANCE?

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, N. B.; Kong, D. F., E-mail: nanbin@ynao.ac.cn [National Astronomical Observatories/Yunnan Observatory, CAS, Kunming 650011 (China)

    2015-12-15

    The Physikalisch Meteorologisches Observatorium Davos total solar irradiance (TSI), Active Cavity Radiometer Irradiance Monitoring TSI, and Royal Meteorological Institute of Belgium TSI are three typical TSI composites. Magnetic Plage Strength Index (MPSI) and Mount Wilson Sunspot Index (MWSI) should indicate the weak and strong magnetic field activity on the solar full disk, respectively. Cross-correlation (CC) analysis of MWSI with three TSI composites shows that TSI should be weakly correlated with MWSI, and not be in phase with MWSI at timescales of solar cycles. The wavelet coherence (WTC) and partial wavelet coherence (PWC) of TSI with MWSI indicate that the inter-solar-cycle variation of TSI is also not related to solar strong magnetic field activity, which is represented by MWSI. However, CC analysis of MPSI with three TSI composites indicates that TSI should be moderately correlated and accurately in phase with MPSI at timescales of solar cycles, and that the statistical significance test indicates that the correlation coefficient of three TSI composites with MPSI is statistically significantly higher than that of three TSI composites with MWSI. Furthermore, the cross wavelet transform (XWT) and WTC of TSI with MPSI show that the TSI is highly related and actually in phase with MPSI at a timescale of a solar cycle as well. Consequently, the CC analysis, XWT, and WTC indicate that the solar weak magnetic activity on the full disk, which is represented by MPSI, dominates the inter-solar-cycle variation of TSI.

  18. RGB color photometry of the solar corona from total solar eclipses

    Science.gov (United States)

    Shopov, Y. Y.; Varonov, A.; Stoykova, D. A.

    2016-02-01

    In the following article we present some of our results from observations of two total solar eclipses (TSE). By combining appropriate photographic equipment and post-processing techniques we show that numerous solar phenomena can be captured in details during TSE. We use color slide RGB photometry technique to visualize invisible regions of the solar corona and to highlight some of the solar phenomena that are very difficult for observation by Earth-based observatories. In fact it reveals more details of the far solar corona than any original image taken from ground-based observations. RGB photometry visualizes different components of the solar corona in one image, which is impossible using conventional observations. This makes it valuable tool for studies of the solar corona. Here we first observe peculiar near infrared emission regions around the upper part of the solar limb during the 1999 TSE. So far its origin is unknown and they need further studies including observations during other solar eclipses. Our observational experiment was designed for other purposes and their registration was completely unexpected.

  19. The Citizen CATE Experiment for the 2017 Total Solar Eclipse

    Science.gov (United States)

    Penn, M. J.

    2015-12-01

    The path of the total solar eclipse of 21 August 2017 passes over about 10 million homes in the USA. Tens of millions more people will travel to the path of totality to view the eclipse first-hand. Using TV and the internet broadcasts, hundreds of millions of people will watch the eclipse, making the event the most viewed astronomical event in the history of mankind. The Citizen Continental-America Telescopic Eclipse (CATE) Experiment for 2017 is being developed at the National Solar Observatory in partnership with universities, schools, astronomy clubs, and corporations. The CATE experiment will use more than 60 identical telescopes equipped with digital cameras positioned from Oregon to South Carolina to image the solar corona. The project will then splice these images together to show the corona during a 90-minute period, revealing for the first time the plasma dynamics of the inner solar corona. The goals for the highly leveraged CATE experiment are diverse and range from providing an authentic STEM research experience for students and lifelong learners, to making state-of-the-art solar coronal observations of the plasma dynamics of coronal polar plumes, to increasing the US scientific literacy. A key goal of this experiment is to donate the telescope and camera system to the volunteer who collects data with it during the total eclipse. The instrument will be then used for a variety of follow-up citizen science projects in astronomy, ranging from solar to cometary to variable star observations. For this reason no government funding is being sought for the equipment costs, but rather private and corporate sources are being developed. The data collected for the 2017 eclipse will be freely available to the scientific, education and amateur astronomy communities. Crowd sourcing the data collection is an essential part of this project, as there are not enough solar physicists in this country to collect these observations. Finally, each site is expected to collect

  20. Solar Radiation at Total Solar Eclipse, 29-March 2006, at Tobruq

    Directory of Open Access Journals (Sweden)

    A. H. Hassan

    2010-01-01

    Full Text Available Problem statement: Measurement of the different components of solar radiation and fractions of these components for the global (horizontal and tracker, direct (white and three colors, yellow, red and infrared and diffuse solar radiation during the solar eclipse, 29 March 2006 at Tobruq, Libya (Lat. 32.08°N and Long. 23.98°E. The time interval of solar eclipse was 2 h: 40 m and the maximum magnitude of eclipse at this region was 0.995. Conclusion: The results showed that the maximum percent of color in the total direct solar radiation during the true eclipse from the first contact to the end contact was in the infrared, where the percent were in the green (11.74%, yellow (15.69%, red (14.88% and infrared (57.68%.

  1. Solar Neutrino Data, Solar Model Uncertainties and Neutrino Oscillations

    CERN Document Server

    Krauss, L M; White, M; Krauss, Lawrence M.; Gates, Evalyn; White, Martin

    1993-01-01

    We incorporate all existing solar neutrino flux measurements and take solar model flux uncertainties into account in deriving global fits to parameter space for the MSW and vacuum solutions of the solar neutrino problem.

  2. Solar Neutrino Data, Solar Model Uncertainties and Neutrino Oscillations

    OpenAIRE

    1992-01-01

    We incorporate all existing solar neutrino flux measurements and take solar model flux uncertainties into account in deriving global fits to parameter space for the MSW and vacuum solutions of the solar neutrino problem.

  3. Identification of moon craters and solar corona during total solar eclipse on 9th March 2016

    Science.gov (United States)

    Luthfiandari; Ekawanti, N.; Purwati, F. G.; Herdiwijaya, D.

    2016-11-01

    Total Solar Eclipse (TSE) is a rare natural event in which the positions of Sun, Moon, and Earth are perfectly aligned. In the past by using this phenomenon, many researches have been done to understand characteristic of the corona. In this paper we carried out the study of TSE which crossed over Indonesia from West to East on 9th March 2016. We observed TSE which occured in Palembang (2.9883° S 104.7513° E), Indonesia. The aim of this research is to understand the effect of moon craters on the appearance of solar corona and identification of solar active regions during TSE. This research was done using Canon SX170 IS camera with ND 5 sun-filter. Although the sky was cloudy during the totality of the phase, coronal video was still taken. Camera also took solar images of partial eclipse phase. Coronal images for every frame were then extracted from the video. Image processing of coronal images was done using RegiStax and PhotoScape freewares. To study solar corona, images from Virtual Moon Atlas, Hinode XRT, and SOHO-LASCO were compared with the result of oriented coronal image. Wider and many more moon craters were found having positive correlation with the brighter effect on solar corona as shown at westward coronal streamer. Those craters are represented by Bel'kovich crater, the biggest one. We also found that only the eastward coronal streamer was correlated with active region, sunspot number 12519, from behind solar limb.

  4. Search for possible solar neutrino radiative decays during total solar eclipses

    CERN Document Server

    Cecchini, S; Giacomelli, G; Giacomelli, R; Popa, V

    2006-01-01

    Total solar eclipses (TSEs) offer a good opportunity to look for photons produced in possible radiative decays of solar neutrinos. In this paper we briefly review the physics bases of such searches as well as the existing limits on the neutrino proper lifetimes obtained by such experiments. We the report on the observations performed in occasion of the 29 March 2006 TSE, from Waw an Namos, Libya.

  5. Prediction of the Solar Corona for the 2017 August 21 Total Solar Eclipse

    Science.gov (United States)

    Mikic, Zoran; Downs, Cooper; Linker, Jon A.; Caplan, Ronald M.; Lionello, Roberto; Torok, Tibor; Titov, Viacheslav; Riley, Pete; Mackay, Duncan; Upton, Lisa

    2017-08-01

    It has become our tradition to predict the structure of the corona prior to eclipses, using a magnetohydrodynamic (MHD) model based on measurements of photospheric magnetic fields on the Sun. We plan to continue this tradition for the August 21, 2017 total solar eclipse that will sweep across the United States. We will predict the structure of the corona using SDO/HMI photospheric magnetic field data, including images of polarization brightness, magnetic field line traces, and images of simulated emission in EUV and X-rays. These images can be compared directly with observations of the total eclipse, as well as observations from SDO/AIA, Hinode/XRT, and STEREO/EUVI. This year we will attempt to energize the magnetic field within filament channels for a more realistic prediction, by constructing flux ropes at the locations where filament channels are observed. The handedness of the flux ropes will be deduced from a magnetofrictional model driven by the evolving photospheric field produced by the Advective Flux Transport model.Research supported by NASA's Heliophysics Supporting Research and Living With a Star Programs.

  6. The Astrophysics of the Solar Corona at the August 21, 2017, American Total Solar Eclipse

    Science.gov (United States)

    Pasachoff, Jay

    2017-01-01

    The first total solar eclipse to cross the United States from coast to coast in 99 years will occur on August 21, 2017, with a 70-mile-wide path of totality from Oregon to South Carolina, with cloudiness statistics more favorable in the northwest than in the southeast. I will discuss a series of observations of the solar corona made during recent solar eclipses and related spacecraft observations. I will further discuss plans for using the 2017 eclipse for furthering our studies of the heating of the solar corona to millions of kelvins, of the dynamics of coronal mass ejections and polar plumes, and of the response of the corona to the solar magnetic field. I will conclude by discussing public-education plans for the eclipse, during which the whole U.S., Mexico, Central America, and Canada will enjoy a partial eclipse. My work at solar eclipses has recently been supported by the NSF and the Committee for Research and Exploration of the National Geographic Society, and I thank them both for research grants for our scientific studies of the 2017 total eclipse, including AGS-1602461 from the NSF and 987816 from National Geographic.

  7. Total Internal Reflection for Effectively Transparent Solar Cell Contacts

    CERN Document Server

    Jahelka, Phillip; Atwater, Harry

    2016-01-01

    A new strategy for eliminating photocurrent losses due to the metal contacts on the front of a solar cell was proposed, simulated, and tested. By placing triangular cross-section lines of low refractive index on top of the contacts, total-internal reflection at the interface of the low-index triangles and the surrounding material can direct light away from the metal and into the photoactive absorber. Simulations indicated that losses can be eliminated for any incident angle, and that yearly energy production improvements commensurate with the metallized area are possible. Proof of principle experiments were carried out to eliminate the reflective losses of a commercial solar cell's busbar contact. Spatially resolved laser beam induced current measurements demonstrated that reflection losses due to the busbar were reduced by voids with triangular cross-section.

  8. Simulation of solar radiation during a total eclipse: a challenge for radiative transfer

    Directory of Open Access Journals (Sweden)

    C. Emde

    2007-01-01

    Full Text Available A solar eclipse is a rare but spectacular natural phenomenon and furthermore it is a challenge for radiative transfer modelling. Whereas a simple one-dimensional radiative transfer model with reduced solar irradiance at the top of the atmosphere can be used to calculate the brightness during partial eclipses a much more sophisticated model is required to calculate the brightness (i.e. the diffuse radiation during the total eclipse. The reason is that radiation reaching a detector in the shadow gets there exclusively by horizontal transport of photons in a spherical shell atmosphere, which requires a three-dimensional radiative transfer model. In this study the first fully three-dimensional simulations for a solar eclipse are presented exemplified by the solar eclipse at 29 March 2006. Using a backward Monte Carlo model we calculated the diffuse radiation in the umbra and simulated the changing colours of the sky. Radiance and irradiance are decreased by 3 to 4 orders of magnitude, depending on wavelength. We found that aerosol has a comparatively small impact on the radiation in the umbra. We also estimated the contribution of the solar corona to the radiation under the umbra and found that it is negligible compared to the diffuse solar radiation in the wavelength region from 310 to 500 nm.

  9. The search for vulcanoids in the 2008 total solar eclipse

    Institute of Scientific and Technical Information of China (English)

    ZHAO HaiBin; LU Hao; ZHAORI GeTu; YAO JinSheng; MA YueHua

    2009-01-01

    Interior to Mercury's orbit is a dynamically stable region where a population of small, asteroid-like bodies called Vuicanoids has been hypothesized to reside. The Vulcanoid Zone (VZ) extends inward from about 0.18 au to about 0.08 au. During the Total Solar Eclipse (TSE) in 2008, a search for Vul-canoids was completed. Although no Vulcanoids was detected to a moving object detection limit of V=12.8, the search was far more comprehensive than previous searches.

  10. Polar plumes dynamics observed during total solar eclipses

    Science.gov (United States)

    Barczynski, K.; Bělík, M.; Marková, E.

    2010-12-01

    Following the successful observation of significant activity in the polar plume during the total solar eclipse in 2006, the analysis of the Sun's polar regions was also carried out in the images obtained in multi-station observations of the eclipse of 2008. In this work polar plumes showing similar although much less significant manifestation of the dynamics have been identified. The dynamics evolution rates have been obtained from comparing the pictures taken at different times. The results are compared with the corresponding phenomena observed in X-rays from the HINODE satellite.

  11. The search for vulcanoids in the 2008 total solar eclipse

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Interior to Mercury’s orbit is a dynamically stable region where a population of small, asteroid-like bodies called Vulcanoids has been hypothesized to reside. The Vulcanoid Zone (VZ) extends inward from about 0.18 au to about 0.08 au. During the Total Solar Eclipse (TSE) in 2008, a search for Vulcanoids was completed. Although no Vulcanoids was detected to a moving object detection limit of V=12.8, the search was far more comprehensive than previous searches.

  12. The 2017 Total Solar Eclipse: Through the Eyes of NASA

    Science.gov (United States)

    Young, C. Alex; Mayo, Louis; Ng, Carolyn; Cline, Troy; Lewis, Elaine; Reed, Shannon; Debebe, Asidesach; Stephenson, Bryan; Odenwald, Sten; Hill, Steele; Wright, Ernest

    2017-01-01

    The August 21, 2017 eclipse will be the first time a total solar eclipse has traversed the Continental US since June 8th, 1918. Anticipation and energy for this eclipse is off the charts! Over 500 million in North America alone will catch the eclipse in either partial or total phase. Parts of South America, Africa, and Europe will see a partial eclipse as well. NASA is planning to take full advantage of this unique celestial event as an education and public engagement opportunity by leveraging its extensive networks of partners, numerous social media platforms, broadcast media, and its significant unique space assets and people to bring the eclipse to America and the world as only NASA can.This talk will outline NASA’s education plans in some detail replicating our many Big Events successes including the 2012 Transit of Venus and the MSL/Curiosity landing and show how scientists and the public can get involved.

  13. Coronal structure and brightness profile of the total solar eclipse on August 1,2008

    Institute of Scientific and Technical Information of China (English)

    ZHAO HaiBin; LIN QiSheng; CHEN YiPing; JIN Sheng; GUAN ZhenBiao; HU Zhongwei

    2009-01-01

    Solar corona is the outermost part of the solar atmosphere.Coronal activities influence space environment between the Sun and the Earth,space weather and the Earth itself.The total solar eclipse (TSE) is the best opportunity to observe the solar corona on ground.During the TSE 2008,a series of images of the corona and partial eclipse of solar disk were obtained using telescope and CCD camera.After image processing,preliminary results of coronal structure are given,and radial brightness profiles of the corona in directions of pole and equator of the Sun are measured.Though in solar activity minimum,the shape and structure of the corona are not symmetry.The equatorial regions are more extent than the polar one,and there are also larger differences between the east and west equatorial regions and between the south and north polar regions.Coronal streamers on east side of the equator,particularly the largest one in east-south direction,are very obvious.The coronal plume in south polar region consists of more polar rays than that in north polar region.These structures are also shown in other observations and data of SOHO.The radial brightness profiles in directions of pole and equator are similar to those of the Van de Hulst model in solar minimum,but there are a few differences due to coronal activity,which is shown in the isophote map of the corona.

  14. Institutional applications of solar total energy systems. Third quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-31

    Estimates are presented of the availability of land for solar total energy (STE) systems. The investigation of the external decision processes that affect an STE system choice was continued. The STE system/utility interface was examined, presenting regional time-of-day pricing scenarios and estimates of backup rates. The possible effects that the financial community could have on STE market penetration was considered. Regional and sectoral energy-use profiles were developed. These profiles served as a basis for simulating yearly system performance on an hourly basis to estimate system costs and savings. Preliminary conceptual designs were developed for both thermal and photovoltaic STE systems. Refined system designs and detailed capital cost and performance estimates for the optimized designs are presented. (MHR)

  15. Optical models for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, T.; Sopori, B. [National Renewable Energy Lab., Golden, CO (United States)

    1995-08-01

    Light trapping is an important design feature for high-efficiency silicon solar cells. Because light trapping can considerably enhance optical absorption, a thinner substrate can be used which, in turn, can lower the bulk carrier recombination and concommitantly increase open-circuit voltage, and fill factor of the cell. The basic concepts of light trapping are similar to that of excitation of an optical waveguide, where a prism or a grating structure increases the phase velocity of the incoming optical wave such that waves propagated within the waveguide are totally reflected at the interfaces. Unfortunately, these concepts break down because the entire solar cell is covered with such a structure, making it necessary to develop new analytical approaches to deal with incomplete light trapping in solar cells. This paper describes two models that analyze light trapping in thick and thin solar cells.

  16. Solar models and solar neutrino oscillations

    OpenAIRE

    2004-01-01

    We provide a summary of the current knowledge, theoretical and experimental, of solar neutrino fluxes and of the masses and mixing angles that characterize solar neutrino oscillations. We also summarize the principal reasons for doing new solar neutrino experiments and what we think may be learned from the future measurements.

  17. Solar models: An historical overview

    Energy Technology Data Exchange (ETDEWEB)

    Bahcall, John N. E-mail: jnb@ias.edu

    2003-04-01

    I will summarize in four slides the 40 years of development of the standard solar model that is used to predict solar neutrino fluxes and then describe the current uncertainties in the predictions. I will dispel the misconception that the p-p neutrino flux is determined by the solar luminosity and present a related formula that gives, in terms of the p-p and {sup 7}Be neutrino fluxes, the ratio of the rates of the two primary ways of terminating the p-p fusion chain. I will also attempt to explain why it took so long, about three and a half decades, to reach a consensus view that new physics is being learned from solar neutrino experiments. Finally, I close with a personal confession.

  18. Solar Models An Historical Overview

    CERN Document Server

    Bahcall, J N

    2002-01-01

    I summarize in four slides the 40 years of development of the standard solar model that is used to predict solar neutrino fluxes and then describe the current uncertainties in the predictions. I next dispel the misconception that the p-p neutrino flux is determined by the solar luminosity and present a related formula that gives, in terms of the p-p and 7Be neutrino fluxes, the ratio of the rates of the two primary ways of terminating the p-p fusion chain. I will also attempt to explain why it took so long, about three and a half decades, to reach a consensus view that new physics is being learned from solar neutrino experiments. Finally, I close with a personal confession.

  19. White light coronal structures and flattening during six total solar eclipses

    OpenAIRE

    B.A. Marzouk; P. Stoeva; Stoev, A.

    2016-01-01

    Solar corona is very important part of the solar atmosphere, which is not available every time and it is very difficult to observe it. From solar corona we can get more information about outer sun layers. Large-scale structure of the solar corona can be studied during total solar eclipses. The structure, shape and brightness of the solar corona significantly change from eclipse to eclipse. They depend on activity of the sun. At maximum solar activity, the corona is very bright and uniform ...

  20. Preliminary results of the solar corona spectroscopic observation of 9th March 2016 Total Solar Eclipse

    Science.gov (United States)

    Sungging Mumpuni, Emanuel; Zamzam Nurzaman, Muhamad; Suryana, Nana

    2016-11-01

    Spectroscopy observation of solar corona has been carried out from 9th March 2016 Total Solar Eclipse expedition in Maba, East Halmahera. Due to limitation by the weather condition during the observation, the obtained data were not favorable. Because of the low signal to noise ratio, the wavelength calibration was not straightforward. To obtain the optimum results, steps for data reduction were performed as the following: selecting the finest data, extracting the 1D spectrum from 2D spectrum, and calibrating spectrum wavelength (including careful interpolation). In this preliminary result, we discuss the instrumentation, the data under investigation, the extraction process of spectrum, and the polynomial interpolation that has been used for extracting information from our data.

  1. Your guide to the 2017 total solar eclipse

    CERN Document Server

    Bakich, Michael E

    2016-01-01

    In this book Astronomy Magazine editor Michael Bakich presents all the information you’ll need to be ready for the total solar eclipse that will cross the United States on August 21, 2017. In this one resource you’ll find out where the eclipse will occur, how to observe it safely, what you’ll experience during the eclipse, the best equipment to choose, how to photograph the event, detailed weather forecasts for locations where the Moon’s shadow will fall, and much more. Written in easy-to-understand language (and with a glossary for those few terms you may not be familiar with), this is the must-have reference for this unique occurrence. It’s not a stretch to say that this eclipse will prove to be the most viewed sky event in history. That’s why even now, more than a year before the eclipse, astronomy clubs, government agencies, cities — even whole states — are preparing for the unprecedented onslaught of visitors whose only desire is to experience darkness at midday. Bakich informs observers ...

  2. The influence of the solar radiation model on the calcutated solar radiation from a horizontal surface to a tilted surface

    DEFF Research Database (Denmark)

    Andersen, Elsa; Lund, Hans; Furbo, Simon

    2004-01-01

    in the calculation. The weather data are measured at the solar radiation measurement station, SMS at the Department of Civil Engineering at the Technical University of Denmark. In this study the weather data are combined with solar collector calculations based on solar collector test carried out at Solar Energy......Measured solar radiation data are most commonly available as total solar radiation on a horizontal surface. When using solar radiation measured on horizontal to calculate the solar radiation on tilted surfaces and thereby the thermal performance of different applications such as buildings and solar...... heating systems, different solar radiation models can be used. The calculation of beam radiation from a horizontal surface to a tilted surface can be done exactly whereas different solar radiation models can calculate the sky diffuse radiation. The sky diffuse radiation can either be assumed evenly...

  3. TOTAL QUALITY CUSTOMER SATISFACTION MODEL

    OpenAIRE

    Jesús Cruz Álvarez; Jesús Fabián López; Carlos Monge Perry

    2014-01-01

    In today’s business environment, all organizations are required to focus on their customers in order to fully understand their needs. There is a need to drive and engage strategic actions in order to close any potentials gaps between customer´s expectations and manufacture´s deliverables. Current customer satisfaction theory appears to be excluded from a holistic model that broadly covers the extent of customer satisfaction concept.This article empathizes the need of an integrated customer sa...

  4. Submillimeter observations of solar limb-brightening in the total solar eclipse of 31 July 1981

    Science.gov (United States)

    Becklin, E. E.; Jefferies, J. T.; Lindsey, C.; Orrall, F.; Gatley, I.; Werner, M.

    1981-01-01

    Eight flights of the Kuiper Airborne Observatory (KAO) were devoted to solar observation. The successful observation of a total solar eclipse was accomplished. The observations were made simultaneously at 30, 50, 100, and 200 microns. The successful adaptation of the KAO for solar observations thus provided the most detailed data to date in this spectral band. The results from a preliminary analysis of the KAO data are summarized: (1) the 200 micron limb is extended about 3 arc sec above the 30 micron limb, indicating the prescence of cool dense material up to the altitudes of spicules; (2) strong radial darkening of the quiet sun intensity profile appeared at 200 microns, probably an indication that hot material in the low chromosphere is recessed into vertical magnetic flux tubes embedded in a cooler nonmagnetic substrate, which obscures the heated material approaching the limb; (3) active regions were observed to undergo a strong increase in contrast above the quiet sun background at wave lengths of 100 microns and longer; and (4) the moon was mapped for use as a photometric standard for determining the absolute intensity of the sun in all four wavelength bands.

  5. Solar spectral irradiance variability in cycle 24: observations and models

    Directory of Open Access Journals (Sweden)

    Marchenko Sergey V.

    2016-01-01

    Full Text Available Utilizing the excellent stability of the Ozone Monitoring Instrument (OMI, we characterize both short-term (solar rotation and long-term (solar cycle changes of the solar spectral irradiance (SSI between 265 and 500 nm during the ongoing cycle 24. We supplement the OMI data with concurrent observations from the Global Ozone Monitoring Experiment-2 (GOME-2 and Solar Radiation and Climate Experiment (SORCE instruments and find fair-to-excellent, depending on wavelength, agreement among the observations, and predictions of the Naval Research Laboratory Solar Spectral Irradiance (NRLSSI2 and Spectral And Total Irradiance REconstruction for the Satellite era (SATIRE-S models.

  6. Electric solar wind sail mass budget model

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2013-02-01

    Full Text Available The electric solar wind sail (E-sail is a new type of propellantless propulsion system for Solar System transportation, which uses the natural solar wind to produce spacecraft propulsion. The E-sail consists of thin centrifugally stretched tethers that are kept charged by an onboard electron gun and, as such, experience Coulomb drag through the high-speed solar wind plasma stream. This paper discusses a mass breakdown and a performance model for an E-sail spacecraft that hosts a mission-specific payload of prescribed mass. In particular, the model is able to estimate the total spacecraft mass and its propulsive acceleration as a function of various design parameters such as the number of tethers and their length. A number of subsystem masses are calculated assuming existing or near-term E-sail technology. In light of the obtained performance estimates, an E-sail represents a promising propulsion system for a variety of transportation needs in the Solar System.

  7. White light coronal structures and flattening during six total solar eclipses

    Science.gov (United States)

    Marzouk, B. A.; Stoeva, P.; Stoev, A.

    2016-12-01

    Solar corona is very important part of the solar atmosphere, which is not available every time and it is very difficult to observe it. From solar corona we can get more information about outer sun layers. Large-scale structure of the solar corona can be studied during total solar eclipses. The structure, shape and brightness of the solar corona significantly change from eclipse to eclipse. They depend on activity of the sun. At maximum solar activity, the corona is very bright and uniform around the solar limb. There are a lot of bright coronal streamers and other active regions on it. During minimum of solar activity the solar corona stretches at the equator and become elliptical. Flattening index is the first quantitative parameter introduced for analyses of the global structure of the solar corona. It varies with respect to the phase of the solar activity and sunspot number. In this paper we study the solar corona during the 1990, 1999, 2006, 2008, 2009 and 2012 total solar eclipses. We obtain flattening coefficients for all the six eclipses by using a new computer program. Our results are in a good agreement with published results.

  8. Predicting the Structure of the Solar Corona for the Total Solar Eclipse of March 29,2006

    Science.gov (United States)

    Mikic, Z.; Linker, J. a.; Lionello, R.; Riley, P.; TItov, V.

    2007-01-01

    We describe the use of a three-dimensional MHD model to predict the s tructure of the corona prior to the total solar eclipse of March 29, 2006. The calculation uses the observed photospheric radial magnetic f ield as a boundary condition. We use a new version of our model that has an improved description of energy transport in the corona. The mo del allows us to predict the emission of X-ray and EUV radiation in t he corona. We compare the predicted polarization brightness in the co rona with four observations of the eclipse from Greece, Egypt, and Li bya, and we demonstrate that the model accurately predicts the largescale structure of the corona. We also compare X-ray emission from the model with GOES/SXI images.

  9. Predicting the Structure of the Solar Corona for the Total Solar Eclipse of March 29,2006

    Science.gov (United States)

    Mikic, Z.; Linker, J. a.; Lionello, R.; Riley, P.; TItov, V.

    2007-01-01

    We describe the use of a three-dimensional MHD model to predict the s tructure of the corona prior to the total solar eclipse of March 29, 2006. The calculation uses the observed photospheric radial magnetic f ield as a boundary condition. We use a new version of our model that has an improved description of energy transport in the corona. The mo del allows us to predict the emission of X-ray and EUV radiation in t he corona. We compare the predicted polarization brightness in the co rona with four observations of the eclipse from Greece, Egypt, and Li bya, and we demonstrate that the model accurately predicts the largescale structure of the corona. We also compare X-ray emission from the model with GOES/SXI images.

  10. Short-term forecast of the total and spectral solar irradiance

    CERN Document Server

    Vieira, Luis Eduardo A; Kretzschmar, Matthieu

    2011-01-01

    Among several heliophysical and geophysical quantities, the accurate evolution of the solar irradiance is fundamental to forecast the evolution of the neutral and ionized components of the Earth's atmosphere.We developed an artificial neural network model to compute the evolution of the solar irradiance in near-real time. The model is based on the assumption that that great part of the solar irradiance variability is due to the evolution of the structure of the solar magnetic field. We employ a Layer-Recurrent Network (LRN) to model the complex relationships between the evolution of the bipolar magnetic structures (input) and the solar irradiance (output). The evolution of the bipolar magnetic structures is obtained from near-real time solar disk magnetograms and intensity images. The magnetic structures are identify and classified according to the area of the solar disk covered. We constrained the model by comparing the output of the model and observations of the solar irradiance made by instruments onboard ...

  11. White light coronal structures and flattening during six total solar eclipses

    Directory of Open Access Journals (Sweden)

    B.A. Marzouk

    2016-12-01

    Flattening index is the first quantitative parameter introduced for analyses of the global structure of the solar corona. It varies with respect to the phase of the solar activity and sunspot number. In this paper we study the solar corona during the 1990, 1999, 2006, 2008, 2009 and 2012 total solar eclipses. We obtain flattening coefficients for all the six eclipses by using a new computer program. Our results are in a good agreement with published results.

  12. Description and primary results of Total Solar Irradiance Monitor, a solar-pointing instrument on an Earth observing satellite

    Science.gov (United States)

    Wang, Hongrui; Fang, Wei; Li, Huiduan

    2015-04-01

    Solar driving mechanism for Earth climate has been a controversial problem for centuries. Long-time data of solar activity is required by the investigations of the solar driving mechanism, such as Total Solar Irradiance (TSI) record. Three Total Solar Irradiance Monitors (TSIM) have been developed by Changchun Institute of Optics, Fine Mechanics and Physics for China Meteorological Administration to maintain continuities of TSI data series which lasted for nearly 4 decades.The newest TSIM has recorded TSI daily with accurate solar pointing on the FY-3C meteorological satellite since Oct 2013. TSIM/FY-3C has a pointing system for automatic solar tracking, onboard the satellite designed mainly for Earth observing. Most payloads of FY-3C are developed for observation of land, ocean and atmosphere. Consequently, the FY-3C satellite is a nadir-pointing spacecraft with its z axis to be pointed at the center of the Earth. Previous TSIMs onboard the FY-3A and FY-3B satellites had no pointing system, solar observations were only performed when the sun swept through field-of-view of the instruments. And TSI measurements are influenced inevitably by the solar pointing errors. Corrections of the solar pointing errors were complex. The problem is now removed by TSIM/FY-3C.TSIM/FY-3C follows the sun accurately by itself using its pointing system based on scheme of visual servo control. The pointing system is consisted of a radiometer package, two motors for solar tracking, a sun sensor and etc. TSIM/FY-3C has made daily observations of TSI for more than one year, with nearly zero solar pointing errors. Short time-scale variations in TSI detected by TSIM/FY-3C are nearly the same with VIRGO/SOHO and TIM/SORCE.Instrument details, primary results of solar pointing control, solar observations and etc will be given in the presentation.

  13. Effects of total solar eclipse of 29 March 2006 on surface radiation

    Directory of Open Access Journals (Sweden)

    S. Kazadzis

    2007-06-01

    Full Text Available Solar irradiance spectral measurements were performed during a total solar eclipse. The spectral effect of the limb darkening to the global, direct irradiance and actinic flux measurements was investigated. This effect leads to wavelength dependent changes in the measured solar spectra showing a much more pronounced decrease in the radiation at the lower wavelengths. Radiative transfer model results were used for the computation of a correction for the total ozone measurements due to the limb darkening. This correction was found too small to explain the large decrease in total ozone column derived from the standard Brewer measurements, which is an artifact in the measured irradiance due to the increasing contribution of diffuse radiation against the decreasing direct irradiance caused by the eclipse. Calculations of the Extraterrestrial spectrum and the effective sun's temperatures, as measured from ground based direct irradiance measurements, showed an artificial change in the calculations of both quantities due to the fact that radiation coming from the visible part of the sun during the eclipse phases differs from the back body radiation described by the Planck's law.

  14. Effects of total solar eclipse of 29 March 2006 on surface radiation

    Directory of Open Access Journals (Sweden)

    S. Kazadzis

    2007-11-01

    Full Text Available Solar irradiance spectral measurements were performed during a total solar eclipse. The spectral effect of the limb darkening to the global, direct irradiance and actinic flux measurements was investigated. This effect leads to wavelength dependent changes in the measured solar spectra showing a much more pronounced decrease in the radiation at the lower wavelengths. Radiative transfer model results were used for the computation of a correction for the total ozone measurements due to the limb darkening. This correction was found too small to explain the large decrease in total ozone column derived from the standard Brewer measurements, which is an artifact in the measured irradiance due to the increasing contribution of diffuse radiation against the decreasing direct irradiance caused by the eclipse. Calculations of the Extraterrestrial spectrum and the effective sun's temperatures, as measured from ground based direct irradiance measurements, showed an artificial change in the calculations of both quantities due to the fact that radiation coming from the visible part of the sun during the eclipse phases differs from the black body radiation described by the Planck's law.

  15. Possible radiative decays of solar neutrinos. Expectations from the total solar eclipse - 11th August 1999

    CERN Document Server

    Tanasa, A

    2001-01-01

    The paper treats the possibility of radiative decays of the oscillation product of the electron neutrinos coming from the Sun; to eliminate the background of photons collected with the telescope, the totality phase of the Total Solar Eclipse from August, 1999 in Romania will be used. To minimize this background in the NOTTE experiment (Neutrino Oscillation with Telescope during the Total Eclipse) one telescope will be mounted aboard a MIG29 plain flying in the totality band at high altitude. A theoretical calculation of the distribution of the distance from the center of the telescope for the decay photons is presented. Similar experiments could be placed aboard satellites having the advantage that the Earth occults the Sun every day while the detection time would be much longer than a typical eclipse duration. A positive result of such an experiment would be relevant not only for neutrino physics but also for astroparticle physics, dark matter searches and cosmology. Even negative results would lead to impro...

  16. Electron Temperatures and Flow Speeds of the Low Solar Corona: MACS Results from the Total Solar Eclipse of 29 March 2006 in Libya

    Science.gov (United States)

    Reginald, Nelson L.; Davila, Joseph M.; SaintCyr, O.; Rabin, Douglas M.; Guhathakurta, Madhulika; Hassler, Donald M.; Gashut, Hadi

    2011-01-01

    An experiment was conducted in conjunction with the total solar eclipse on 29 March 2006 in Libya to measure both the electron temperature and its flow speed simultaneously at multiple locations in the low solar corona by measuring the visible K-coronal spectrum. Coronal model spectra incorporating the effects of electron temperature and its flow speed were matched with the measured K-coronal spectra to interpret the observations. Results show electron temperatures of (1.10 +/- 0.05) MK, (0.70 +/- 0.08) MK, and (0.98 +/- 0.12) MK, at 1.1 Solar Radius from Sun center in the solar north, east and west, respectively, and (0.93 +/- 0.12) MK, at 1.2 Solar Radius from Sun center in the solar west. The corresponding outflow speeds obtained from the spectral fit are (103 +/- 92) km/s, (0 + 10) km/s, (0+10) km/s, and (0+10) km/s. Since the observations were taken only at 1.1 Solar Radius and 1.2 Solar Radius from Sun center, these speeds, consistent with zero outflow, are in agreement with expectations and provide additional confirmation that the spectral fitting method is working. The electron temperature at 1.1 Solar Radius from Sun center is larger at the north (polar region) than the east and west (equatorial region).

  17. Electron Temperatures and Flow Speeds of the Low Solar Corona: MACS Results from the Total Solar Eclipse of 29 March 2006 in Libya

    Science.gov (United States)

    Reginald, Nelson L.; Davila, Joseph M.; SaintCyr, O.; Rabin, Douglas M.; Guhathakurta, Madhulika; Hassler, Donald M.; Gashut, Hadi

    2011-01-01

    An experiment was conducted in conjunction with the total solar eclipse on 29 March 2006 in Libya to measure both the electron temperature and its flow speed simultaneously at multiple locations in the low solar corona by measuring the visible K-coronal spectrum. Coronal model spectra incorporating the effects of electron temperature and its flow speed were matched with the measured K-coronal spectra to interpret the observations. Results show electron temperatures of (1.10 +/- 0.05) MK, (0.70 +/- 0.08) MK, and (0.98 +/- 0.12) MK, at 1.1 Solar Radius from Sun center in the solar north, east and west, respectively, and (0.93 +/- 0.12) MK, at 1.2 Solar Radius from Sun center in the solar west. The corresponding outflow speeds obtained from the spectral fit are (103 +/- 92) km/s, (0 + 10) km/s, (0+10) km/s, and (0+10) km/s. Since the observations were taken only at 1.1 Solar Radius and 1.2 Solar Radius from Sun center, these speeds, consistent with zero outflow, are in agreement with expectations and provide additional confirmation that the spectral fitting method is working. The electron temperature at 1.1 Solar Radius from Sun center is larger at the north (polar region) than the east and west (equatorial region).

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

    Energy Technology Data Exchange (ETDEWEB)

    Piacentini, Ruben D. [Instituto de Fisica Rosario (CONICET-Universidad Nacional de Rosario), 27 de Febrero 210bis, 2000 Rosario (Argentina); Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Pellegrini 250, 2000 Rosario (Argentina); Salum, Graciela M. [Instituto de Fisica Rosario (CONICET-Universidad Nacional de Rosario), 27 de Febrero 210bis, 2000 Rosario (Argentina); Facultad Regional Concepcion del Uruguay, Universidad Tecnologica Nacional, Concepcion del Uruguay (Argentina); Fraidenraich, Naum; Tiba, Chigueru [Grupo de Pesquisas em Fontes Alternativas de Energia, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, 1000 - 50.740-540, Recife, PE (Brazil)

    2011-01-15

    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). They were obtained at sea level of the intertropical Atlantic coast, in the city of Recife, Brazil, in the period February 2008-January 2009. Extreme total solar irradiance values larger than CSC were measured during 3.4% of the days of the total registered period. This percentage increases to 7.4% for global solar irradiance within 95.1-100% of the CSC and to 15.3% within 90.1-95% of the CSC. The largest extreme total solar irradiance value, 1477 {+-} 30 W/m{sup 2}, was registered the 28th of March 2008 at 11:34 local time (UT - 3h). It overpassed by 7.9% the CSC value for this day (1369.4 W/m{sup 2}) and by 42.3% the estimated value of the clear sky Iqbal C radiation model (1037.7 W/m{sup 2}). The observation of extreme values should be taken into account in the study of solar radiation effects related to materials exposed to the outside, UV index and biological effects, among others. Also, the detailed knowledge of this interesting effect may contribute significantly to clarify physical aspects about the interaction of global solar radiation with the ecosystem and climate change. (author)

  19. Solar Radiation Model for Development and Control of Solar Energy Sources

    Directory of Open Access Journals (Sweden)

    Dominykas Vasarevičius

    2016-06-01

    Full Text Available The model of solar radiation, which takes into account direct, diffused and reflected components of solar energy, has been presented. Model is associated with geographical coordinates and local time of every day of the year. It is shown that using analytic equations for modelling the direct component, it is possible to adopt it for embedded systems with low computational power and use in solar tracking applications. Reflected and diffused components are especially useful in determining the performance of photovoltaic modules in certain location and surroundings. The statistical method for cloud layer simulation based on local meteorological data is offered. The presented method can’t be used for prediction of weather conditions but it provides patterns of solar radiation in time comparable to those measured with pyranometer. Cloud layer simulation together with total solar radiation model is a useful tool for development and analysis of maximum power point tracking controllers for PV modules.

  20. Institutional applications of solar total-energy systems. Draft final report. Volume 2. Appendixes

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-07-01

    The appendices present the analytical basis for the analysis of solar total energy (STE) systems. A regional-climate model and a building-load requirements model are developed, along with fuel-price scenarios. Life-cycle costs are compared for conventional-utility, total energy, and STE systems. Thermal STE system design trade-offs are performed and thermal STE system performance is determined. The sensitivity of STE competitiveness to fuel prices is examined. The selection of the photovoltaic array is briefly discussed. The institutional-sector decision processes are analyzed. Hypothetical regional back-up rates and electrical-energy costs are calculated. The algorithms and equations used in operating the market model are given, and a general methodology is developed for projecting the size of the market for STE systems and applied to each of 8 institutional subsectors. (LEW)

  1. Ludendorff Coronal Flattening Index of the Total Solar Eclipse on March 9, 2016

    CERN Document Server

    Dani, Tiar; Rachman, Abdul

    2016-01-01

    Ludendorff coronal flattening index of the Total Solar Eclipse (TSE) on March 9, 2016, was calculated at various distances in solar radius. As a result, we obtained the coronal flattening index $\\left(\\epsilon =a+b\\right)$ at a distance of 2 solar radii is 0.16. The $24^{th}$ solar cycle phase based on the 2016 TSE event obtained -0.64 which showed the corona is pre-minimum type. Resulted coronal flattening index value gives a predicted maximum amplitude of the monthly sunspot number ($W_{max}$) for the $25^{th}$ solar cycle to be $70\\pm65$. Therefore, the solar activity for $25^{th}$ solar cycle predicted to be lower than the current solar cycle, which has a maximum sunspot number value of 146 in February 2014

  2. A Smoothed Eclipse Model for Solar Electric Propulsion Trajectory Optimization

    Science.gov (United States)

    Aziz, Jonathan; Scheeres, Daniel; Parker, Jeffrey; Englander, Jacob

    2017-01-01

    Solar electric propulsion (SEP) is the dominant design option for employing low-thrust propulsion on a space mission. Spacecraft solar arrays power the SEP system but are subject to blackout periods during solar eclipse conditions. Discontinuity in power available to the spacecraft must be accounted for in trajectory optimization, but gradient-based methods require a differentiable power model. This work presents a power model that smooths the eclipse transition from total eclipse to total sunlight with a logistic function. Example trajectories are computed with differential dynamic programming, a second-order gradient-based method.

  3. Clear-Sky Probability for the August 21, 2017, Total Solar Eclipse Using the NREL National Solar Radiation Database

    Energy Technology Data Exchange (ETDEWEB)

    Habte, Aron M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Roberts, Billy J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kutchenreiter, Mark C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sengupta, Manajit [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wilcox, Steve [Solar Resource Solutions, LLC, Lakewood, CO (United States); Stoffel, Tom [Solar Resource Solutions, LLC, Lakewood, CO (United States)

    2017-07-21

    The National Renewable Energy Laboratory (NREL) and collaborators have created a clear-sky probability analysis to help guide viewers of the August 21, 2017, total solar eclipse, the first continent-spanning eclipse in nearly 100 years in the United States. Using cloud and solar data from NREL's National Solar Radiation Database (NSRDB), the analysis provides cloudless sky probabilities specific to the date and time of the eclipse. Although this paper is not intended to be an eclipse weather forecast, the detailed maps can help guide eclipse enthusiasts to likely optimal viewing locations. Additionally, high-resolution data are presented for the centerline of the path of totality, representing the likelihood for cloudless skies and atmospheric clarity. The NSRDB provides industry, academia, and other stakeholders with high-resolution solar irradiance data to support feasibility analyses for photovoltaic and concentrating solar power generation projects.

  4. Solar Model Parameters and Direct Measurements of Solar Neutrino Fluxes

    CERN Document Server

    Bandyopadhyay, A; Goswami, S; Petcov, S T; Bandyopadhyay, Abhijit; Choubey, Sandhya; Goswami, Srubabati

    2006-01-01

    We explore a novel possibility of determining the solar model parameters, which serve as input in the calculations of the solar neutrino fluxes, by exploiting the data from direct measurements of the fluxes. More specifically, we use the rather precise value of the $^8B$ neutrino flux, $\\phi_B$ obtained from the global analysis of the solar neutrino and KamLAND data, to derive constraints on each of the solar model parameters on which $\\phi_B$ depends. We also use more precise values of $^7Be$ and $pp$ fluxes as can be obtained from future prospective data and discuss whether such measurements can help in reducing the uncertainties of one or more input parameters of the Standard Solar Model.

  5. Predictions for the total solar eclipse of 1991

    Science.gov (United States)

    Espenak, Fred

    1989-01-01

    A total eclipse of the sun will be widely visible from the Western Hemisphere on July 11, 1991. Detailed predictions for this event are presented which include tables of geographic coordinates for the northern limit, southern limit and center line of the path of totality, local circumstances on the center line and for 95 cities within the partial and total eclipse paths, maps depicting the path of totality, the sky during totality and the lunar limb profile. The author discusses the general characteristics of the eclipse including local circumstances from various points along the central path, the Saros series history and effects caused by the lunar limb profile.

  6. Simulation and modeling of solar radiation in Saudi Arabia

    Energy Technology Data Exchange (ETDEWEB)

    Zuhairy, A.A.; Sayigh, A.A.M. [Reading Univ. (United Kingdom). Dept. of Engineering

    1995-04-01

    A mathematical model is used to generate the hourly data for the total solar radiation on a horizontal surface. The generated data are based on the hourly recorded visibility data for 20 years (1970-1989). The model year technique was then applied to model the 20 years of hourly data of solar radiation into one statistically representative year. A model year of hourly data was then generated for the beam and diffuse components of solar radiation on a horizontal surface. Similarly, a model year of hourly data was also generated for the total solar radiation on tilted surfaces with different orientations with its beam, diffuse and reflected components. A simple methodology is proposed for calculating the solar radiation on vertical surfaces, based on a solar impact factor (SIF). Monthly means and daily totals of hourly sums for each month of the year are discussed. The hourly data of solar radiation for a typical day for each month of the year are presented. The data were generated for the four climatic zones of Saudi Arabia, the hot-dry (Riyadh), the warm-humid (Jeddah), the maritime inland desert climate (Dhahran) and the upland climate zone (Taif). The accuracy of the results is discussed and found to be above 90% representative. (author)

  7. TOTAL REWARDS MODEL IN ROMANIAN COMPANIES

    Directory of Open Access Journals (Sweden)

    Elena-Sabina HODOR

    2014-04-01

    Full Text Available Total Rewards Management is a subject of major importance for companies, because, by using models for this, firms can achieve their objectives of high performance. In order to analyse a validated total rewards model in Romanian Accounting and Consulting Companies, it is used The WorldatWork Total Rewards Model, which depict what contributes to applicant attraction and employee motivation and retention. Thus, the methodology of the previous survey is adjusted to the local context. The conclusions for the methodological aspects illustrate that the present research involves three strategic steps in order to achieve the objectives presented: the analysis of organizational environment of the companies from the sample, checking if Total Rewards Model proposed in the previous research is applicable for the same romanian companies from the previous survey, the analysing of the differences between results, and, if necessary, the adaptation of the model for Romania.

  8. TOTAL REWARDS MODEL IN ROMANIAN COMPANIES

    Directory of Open Access Journals (Sweden)

    Elena-Sabina HODOR

    2014-04-01

    Full Text Available Total Rewards Management is a subject of major importance for companies, because, by using models for this, firms can achieve their objectives of high performance. In order to analyse a validated total rewards model in Romanian Accounting and Consulting Companies, it is used The WorldatWork Total Rewards Model, which depict what contributes to applicant attraction and employee motivation and retention. Thus, the methodology of the previous survey is adjusted to the local context. The conclusions for the methodological aspects illustrate that the present research involves three strategic steps in order to achieve the objectives presented: the analysis of organizational environment of the companies from the sample, checking if Total Rewards Model proposed in the previous research is applicable for the same romanian companies from the previous survey, the analysing of the differences between results, and, if necessary, the adaptation of the model for Romania.

  9. Predictions for the total solar eclipse of 1988

    Science.gov (United States)

    Espenak, Fred

    1987-01-01

    A total eclipse of the sun will be widely visible from the East Indies on March 18, 1988. Detailed predictions for this event are presented which include tables of geographic coordinates for the northern limit, center line and southern limit of the path of totality, local circumstances for 40 cities within the total and partial eclipse paths, the lunar-limb profile, and maps depicting the path of totality. The author discusses the general characteristics of the eclipse, local circumstances from various points along the central path and the Saros-series history.

  10. [Analysis of urban thermal environment change characteristics during the total solar eclipse].

    Science.gov (United States)

    Lu, Jun; Chen, Shi-Ling; Bu, Cui-Wen; Liu, Yu-Xi

    2011-04-01

    There was a very good observation area in Chongqing for the total solar eclipse along the Changjiang river on 22 July, 2009. Through the experiments, the outdoor meteorological data (solar radiation, air temperature and relative humidity) were observed and recorded on 21 July and 22 July. Based on the experimental observation data, the effect of thermal environment in Chongqing area was to analyzed and discussed. Experiment indicates that the reduction of air temperature and surface temperature resulted in the decrease in the solar radiation intensity, and the amplitude of the air temperature change is 2.4 degrees C during the total solar eclipse. Compared with the two days' air temperature, the amplitude of the air temperature change reached 4.6 degrees C on account of the total solar eclipse.

  11. Implications of solar wind measurements for solar models and composition

    Science.gov (United States)

    Serenelli, Aldo; Scott, Pat; Villante, Francesco L.; Vincent, Aaron C.; Asplund, Martin; Basu, Sarbani; Grevesse, Nicolas; Peña-Garay, Carlos

    2016-11-01

    We critically examine recent claims of a high solar metallicity by von Steiger & Zurbuchen (2016, vSZ16) based on in situ measurements of the solar wind, rather than the standard spectroscopically inferred abundances (Asplund et al. 2009, hereafter AGSS09). We test the claim by Vagnozzi et al. (2016) that a composition based on the solar wind enables one to construct a standard solar model in agreement with helioseismological observations and thus solve the decades-old solar modelling problem. We show that, although some helioseismological observables are improved compared to models computed with spectroscopic abundances, most are in fact worse. The high abundance of refractory elements leads to an overproduction of neutrinos, with a predicted 8B flux that is nearly twice its observed value, and 7Be and CNO fluxes that are experimentally ruled out at high confidence. A combined likelihood analysis shows that models using the vSZ16 abundances are worse than AGSS09 despite a higher metallicity. We also present astrophysical and spectroscopic arguments showing the vSZ16 composition to be an implausible representation of the solar interior, identifying the first ionization potential effect in the outer solar atmosphere and wind as the likely culprit.

  12. Solar Radiation at Total Solar Eclipse, 29-March 2006, at Tobruq

    OpenAIRE

    A. H. Hassan; U. A. Rahoma

    2010-01-01

    Problem statement: Measurement of the different components of solar radiation and fractions of these components for the global (horizontal and tracker), direct (white and three colors, yellow, red and infrared) and diffuse solar radiation during the solar eclipse, 29 March 2006 at Tobruq, Libya (Lat. 32.08°N and Long. 23.98°E). The time interval of solar eclipse was 2 h: 40 m and the maximum magnitude of eclipse at this region was 0.995. Conclusion: The results showed th...

  13. Public outreach and education during the 2016 total solar eclipse in Palu and Malang

    Science.gov (United States)

    Rachmadian, A. P.; Kunjaya, C.; Wahono, W.; Anugrah, A. A.

    2016-11-01

    MAGIC (Ma Chung Galactic Club) of Ma Chung University, Malang, is one of the amateur astronomers club who did public outreach and education during the Total Solar Eclipse March 9, 2016. The motivation for doing this was the bad experience during Total Solar Eclipse 1983. At that time the Indonesian government forbid the people to observe the Total Solar Eclipse in a way to avoid blindness. We try to fix this misunderstanding by educating people the safe way to enjoy the partial and total solar eclipse. MAGIC team was divided into two teams, one team went to Palu and did the solar eclipse related education in six high schools before and during the eclipse. The other team did the observation on Ma Chung University campus, Malang, to accompany people who want to see the partial solar eclipse through filtered telescopes. The sky during the solar eclipse was clear both in Malang and Palu. People were very excited and satisfied with the solar eclipse, and their interest to astronomy is increased.

  14. Fort Hood Solar Total Energy Project. Volume III. Engineering drawings. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1979-01-01

    Engineering drawings are presented for the Solar Total Energy System at Fort Hood, Texas. Drawings are given for the solar collector subsystem, power conversion subsystem, instrumentation and control subsystem, thermal storage subsystem, site preparation, thermal storage area piping and equipment layout, heating/cooling and domestic hot water subsystem, STES building and facility, and electrical distribution. (WHK)

  15. Investigation of the solar wind outflows and joint observations during the total solar eclipse of March 29, 2006

    Science.gov (United States)

    Abbo, Lucia; Zangrilli, Luca; Antonucci, Ester; Fineschi, Silvano; Kohl, John; Giordano, Silvio; Massone, Giuseppe; Capobianco, Gerardo; Calcidese, Paolo; Porcu, Francesco

    During the total solar eclipse of 29 March 2006, SOHO observations of JOP158 were coordinated with ground based instruments. In particular, the Ultraviolet Coronagraph Spectrometer (UVCS) onboard SOHO has observed the south coronal hole in the OVI doublet emission in order to probe the role of plume and interplume regions in the dynamics of the fast solar wind. From the analysis of the polarized K-solar corona measurements obtained with the EKPol polarimeter from the site of c (desert of Sahara, Lybia), we estimate the coronal electron density radial profiles and perform a Doppler dimming analysis of the OVI doublet line intensities to measure the outflow velocity.

  16. Total electron count variability and stratospheric ozone effects on solar backscatter and LWIR emissions

    Science.gov (United States)

    Ross, John S.; Fiorino, Steven T.

    2017-05-01

    The development of an accurate ionospheric Total Electron Count (TEC) model is of critical importance to high frequency (HF) radio propagation and satellite communications. However, the TEC is highly variable and is continually influenced by geomagnetic storms, extreme UV radiation, and planetary waves. Being able to capture this variability is essential to improve current TEC models. The growing body of data involving ionospheric fluctuations and stratospheric variations has revealed a correlation. In particular, there is a marked and persistent association between increases in stratospheric ozone and variability of the TEC. The spectral properties of ozone show that it is a greenhouse gas that alters long wave emissions from Earth and interacts with the UV spectrum coming from the sun. This study uses the Laser Environment Effects Definition and Reference (LEEDR) radiative transfer and atmospheric characterization code to model the effects of changes in stratospheric ozone on solar backscatter and longwave (LWIR) terrestrial emissions and infer TEC and TEC variability.

  17. Mid-South solar total energy: institutional analysis. Final report, May 1, 1978-December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Powe, R.E.; Carley, C.T.; Forbes, R.E.; Johnson, L.R.; Stiffler, A.K.; Hodge, B.K.; Bouchillon, C.W.

    1979-01-01

    A comprehensive survey was undertaken to determine the current usage of energy by the Mississippi State University, considering electricity and fuel separately. A variety of individual components likely to be employed in total energy systems are then considered in detail, including: solar assisted space heating system, space cooling system design, solar electric system, flat plate solar collector system, central solar receiver, and geothermal heat pump system. Also, algorithms have been developed for the approximate prediction of building heating and cooling loads based on gross parameters such as floor area, type of wall construction, etc. System considerations and evaluation are then presented. (LEW)

  18. Ludendorff Coronal Flattening Index of the Total Solar Eclipse on March 9, 2016

    OpenAIRE

    Dani, Tiar; Priyatikanto, Rhorom; Rachman, Abdul

    2016-01-01

    Ludendorff coronal flattening index of the Total Solar Eclipse (TSE) on March 9, 2016, was calculated at various distances in solar radius. As a result, we obtained the coronal flattening index $\\left(\\epsilon =a+b\\right)$ at a distance of 2 solar radii is 0.16. The $24^{th}$ solar cycle phase based on the 2016 TSE event obtained -0.64 which showed the corona is pre-minimum type. Resulted coronal flattening index value gives a predicted maximum amplitude of the monthly sunspot number ($W_{max...

  19. Modelling total energy costs of sports centres

    Energy Technology Data Exchange (ETDEWEB)

    Boussabaine, A.H.; Kirkham, R.J.; Grew, R.J. [Liverpool Univ., School of Architecture and Building Engineering, Liverpool (United Kingdom)

    1999-12-07

    Providing and maintaining safe and comfortable conditions in sport centres raises many issues, particularly cost. The paper gives an overview of the factors associated with sport centre servicing and attempts to highlight the governing factors associated with this, particularly energy costs. A total of 19 sport centres in the City of Liverpool in the UK are investigated, using data elicited from the Liverpool Leisure Services Directorate. The energy operating costs were analysed using statistical methods. Six models were developed to predict total energy costs. Testing and validation results showed a high level of model accuracy. The models would be of use to professionals involved in feasibility studies at the design stage. (Author)

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

    CERN Document Server

    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...

  1. The effect of the total solar eclipse of 29 March 2006 on meteorological variables in Greece

    Directory of Open Access Journals (Sweden)

    D. Founda

    2007-11-01

    Full Text Available This paper examines the effect of the total solar eclipse of 29 March 2006 on meteorological variables across Greece. Integrated micrometeorological measurements were conducted at Kastelorizo, a small island within the path of totality, and other sites within the Greek domain, with various degrees of solar obscuration. The observations showed a dramatic reduction in the incoming global radiation and subsequent, pronounced changes in surface air temperature with the lowest temperature values occurring about 15 min after the full phase. The amplitude of the air temperature drop was not analogous to the obscuration percentage but was principally determined by the surrounding environment (mainly the sea influence, the background meteorological conditions and local cloudiness. Surface wind-speed decreased in most sites as a result of the cooling and stabilization of the atmospheric boundary layer. This perturbation provided a unique opportunity to apply a sensitivity analysis on the effect of the eclipse to the Weather Research and Forecast (WRF numerical mesoscale meteorological model. Strong anomalies, not associated with a dynamic response, were simulated over land especially in surface air temperature. The simulated temperature drop pattern was consistent with the observations.

  2. The effect of the total solar eclipse of 29 March 2006 on meteorological variables in Greece

    Directory of Open Access Journals (Sweden)

    D. Founda

    2007-07-01

    Full Text Available This paper examines the effect of the total solar eclipse of 29 March 2006 on meteorological variables across Greece. Integrated micrometeorological measurements were conducted at Kastelorizo, a small island within the path of totality, and other sites within the Greek domain, with various degrees of solar obscuration. The observations showed a dramatic reduction in the incoming global radiation and subsequent, pronounced changes in surface air temperature with the lowest temperature values occurring about 15 min after the full phase. The amplitude of the air temperature drop was not analogous to the obscuration percentage but was principally determined by the surrounding environment (mainly the sea influence, the background meteorological conditions and local cloudiness. Surface wind-speed decreased in most sites as a result of the cooling and stabilization of the atmospheric boundary layer. This perturbation provided a unique opportunity to apply a sensitivity analysis on the effect of the eclipse to the Weather Research and Forecast (WRF numerical mesoscale meteorological model. Strong anomalies, not associated with a dynamic response, were simulated over land especially in surface air temperature. The simulated temperature drop pattern was consistent with the observations.

  3. The 1st of April 2470 BC Total Solar Eclipse Seen by the Prophet Ibraheem

    Science.gov (United States)

    Yousef, S. M.

    The Holy Quran describes a phenomenon seen by young Abraham that can only fit a solar eclipse. Two criteria were given for this particular eclipse; first only one planet was seen as soon as it got dark and second no corona was seen. In order to justify the first selection rule, examinations of solar and planetary longitudes for total solar eclipses passing over Babel were carried out. Only the eclipse of the 1st of April 2470 BC meets this condition, as it was only Venus that was seen at that eclipse. The second selection rule was also naturally fulfilled, as Babel happened to be on the border of the totality zone hence no corona was seen, however all the time the moon glistened as Baily's beads. There is no doubt that the prophet Abraham witnessed the 1st of April total solar eclipse that passed over Babel. This will put him about 470 years backward than it was previously anticipated.

  4. Spectroscopic Coronal Observations during the Total Solar Eclipse of 11 July 2010

    CERN Document Server

    Voulgaris, A G; Seiradakis, J H; Pasachoff, J M; Economou, T E

    2012-01-01

    The flash spectrum of the solar chromosphere and corona was measured with a slitless spectrograph before, after, and during the totality of the solar eclipse, of 11 July 2010, at Easter Island, Chile. This eclipse took place at the beginning of the Solar Cycle 24, after an extended minimum of solar activity. The spectra taken during the eclipse show a different intensity ratio of the red and green coronal lines compared with those taken during the total solar eclipse of 1 August 2008, which took place towards the end of the Solar Cycle 23. The characteristic coronal forbidden emission line of forbidden Fe XIV (5303 {\\AA}) was observed on the east and west solar limbs in four areas relatively symmetrically located with respect to the solar rotation axis. Subtraction of the continuum flash-spectrum background led to the identification of several extremely weak emission lines, including forbidden Ca XV (5694 {\\AA}), which is normally detected only in regions of very high excitation, e.g., during flares or above ...

  5. A formal model for total quality management

    NARCIS (Netherlands)

    S.C. van der Made-Potuijt; H.B. Bertsch (Boudewijn); L.P.J. Groenewegen

    1996-01-01

    textabstractTotal Quality Management (TQM) is a systematic approach to managing a company. TQM is systematic in the sense that it is uses facts through observation, analysis and measurable goals. There are theoretical descriptions of this management concept, but there is no formal model of it. A for

  6. A formal model for total quality management

    NARCIS (Netherlands)

    S.C. van der Made-Potuijt; H.B. Bertsch (Boudewijn); L.P.J. Groenewegen

    1996-01-01

    textabstractTotal Quality Management (TQM) is a systematic approach to managing a company. TQM is systematic in the sense that it is uses facts through observation, analysis and measurable goals. There are theoretical descriptions of this management concept, but there is no formal model of it. A

  7. Method of frequency dependent correlations: investigating the variability of total solar irradiance

    Science.gov (United States)

    Pelt, J.; Käpylä, M. J.; Olspert, N.

    2017-03-01

    Context. This paper contributes to the field of modeling and hindcasting of the total solar irradiance (TSI) based on different proxy data that extend further back in time than the TSI that is measured from satellites. Aims: We introduce a simple method to analyze persistent frequency-dependent correlations (FDCs) between the time series and use these correlations to hindcast missing historical TSI values. We try to avoid arbitrary choices of the free parameters of the model by computing them using an optimization procedure. The method can be regarded as a general tool for pairs of data sets, where correlating and anticorrelating components can be separated into non-overlapping regions in frequency domain. Methods: Our method is based on low-pass and band-pass filtering with a Gaussian transfer function combined with de-trending and computation of envelope curves. Results: We find a major controversy between the historical proxies and satellite-measured targets: a large variance is detected between the low-frequency parts of targets, while the low-frequency proxy behavior of different measurement series is consistent with high precision. We also show that even though the rotational signal is not strongly manifested in the targets and proxies, it becomes clearly visible in FDC spectrum. A significant part of the variability can be explained by a very simple model consisting of two components: the original proxy describing blanketing by sunspots, and the low-pass-filtered curve describing the overall activity level. The models with the full library of the different building blocks can be applied to hindcasting with a high level of confidence, Rc ≈ 0.90. The usefulness of these models is limited by the major target controversy. Conclusions: The application of the new method to solar data allows us to obtain important insights into the different TSI modeling procedures and their capabilities for hindcasting based on the directly observed time intervals.

  8. Semi-empirical model of solar plages

    Institute of Scientific and Technical Information of China (English)

    FANG; Cheng

    2001-01-01

    [1] Zirin, H., Astrophysics of the Sun, Chapter 7, Cambridge: Cambridge University Press, 1988.[2] Shine, R. A., Linsky, J. L., Physical properties of solar chromospheric plages II. Chromospheric plage models, Solar Phys., 1974, 39: 49.[3] Kelch, W. L., Linsky, J. L., Physical properties of solar chromospheric plages III. Models based on CaII and MgII observations, Solar Phys., 1978, 58: 37.[4] Lemaire, P., Goutlebroze, J. C., Vial, J. C. et al., Physical properties of the solar chromosphere deduced from optically thick lines, A & A, 1981, 103: 160.[5] Fontenla, J. M., Avrett, E. H., Loeser, R., Energy balance in the solar transition region II. Effects of pressure and energy input on hydrostatic models, ApJ, 1991, 377: 712.[6] Fontenla, J. M., Avrett, E. H., Loeser, R., Energy balance in the solar transition region III. Helium emission in hydrostatic, constant-abundance models with diffusion, ApJ, 1993, 406: 319.[7] Pierce, A. K., Slaughter, C., Solar limb darkening I: λλ(30337297), Solar Phys., 1977, 51: 25.[8] Pierce, A. K., Slaughter, C., Weinberger, D., Solar limb darkening in the interval 740424018*!, II, Solar Phys., 1977, 52: 179.[9] Nechel, H., Labs, D., The solar radiation between 3300 and 12500*!, Solar Phys., 1984, 90: 205.[10] Vernazza, J. E., Avrett, E. H., Loeser, R., Structure of the solar chromosphere I. Basic computations and summary of the results, ApJ, 1973, 184: 605.[11] Mihalas, D., Stellar Atmospheres, San Francisco: W. H. Freeman and Company, 1978.[12] Fang, C., Hnoux, J. -C., Self-consistent model of flare heated solar chromosphere, A & A, 1983, 118: 139.[13] Ding, M. D., Fang, C., A semi-empirical model of sunspot penumbra, A & A, 1989, 225: 204.[14] Vernazza, J. E., Avrett, E. H., Loeser, R., Structure of the solar chromosphere III. Models of the EUV brightness components of the quiet Sun, ApJ Suppl., 1981, 45: 635.[15] Canfield, R. C., Athey, R

  9. Implications of solar wind measurements for solar models and composition

    CERN Document Server

    Serenelli, Aldo; Villante, Francesco L; Vincent, Aaron C; Asplund, Martin; Basu, Sarbani; Grevesse, Nicolas; Pena-Garay, Carlos

    2016-01-01

    We critically examine recent claims of a high solar metallicity by von Steiger \\& Zurbuchen (2016; vSZ16) based on in situ measurements of the solar wind, rather than the standard spectroscopically-inferred abundances (Asplund et al. 2009). We test the claim by Vagnozzi et al. (2016) that a composition based on the solar wind enables one to construct a standard solar model in agreement with helioseismological observations and thus solve the decades-old solar modelling problem. We show that, although some helioseismological observables are improved compared to models computed with established abundances, most are in fact worse. The high abundance of refractory elements leads to an overproduction of neutrinos, with a predicted $^8$B flux that is nearly twice its observed value, and $^7$Be and CNO fluxes that are experimentally ruled out at high confidence. A combined likelihood analysis shows that models using the vSZ16 abundances fare much worse than AGSS09 despite a higher metallicity. We also present ast...

  10. White light corona during total solar eclipse on March 9, 2016

    Science.gov (United States)

    Imaduddin, Irfan; Akbar, Evan I.; Putri, Gerhana P.

    2016-11-01

    We observed the white-light corona during the total solar eclipse of 2016 March 9 from Corong Beach, East Borneo. The solar corona is nearly circular with exception on the southern part of the Sun. Coronal structures are clearly seen. Based on the data, we obtained the Ludendorff flattening index, Nikolsky geometric flattening index, and phases of solar activity (Φ and P) are 0.129, 1.32, -0.716, and 0.573 respectively. Relation between Ludendorff and Nikolsky index, sunspot number, and phases of solar activity were discussed. We also predicted the amplitude of solar cycle 25 to be 196 ± 52 (based on 13-month smoothed monthly data) and 130 ± 42 (based on monthly sunspot number data).

  11. The Temperature of the Corona as Derived from Total Solar Eclipse Observations

    Science.gov (United States)

    Habbal, Shadia R.; Morgan, Huw; Druckmuller, Miloslav; Ding, Adalbert

    2016-05-01

    Multiwavelength imaging observations in a suite of coronal forbidden lines of the corona during total solar eclipses enables the empirical inference of the spatial distribution of temperature in the solar corona up to a few solar radii above the limb. The temperature sensitivity of coronal emission lines is such that temperature differences of 105 K can be detected in the images. Using high resolution multiwavelength and white light eclipse images acquired since 2006, covering almost a solar cycle, we show evidence for (1) how the distribution of the temperature in the corona is bimodal, with closed coronal structures dominated by 2 106 K plasma, while structures streaming away from the Sun are dominated by 106 K emission, (2) prominences are invariably enshrouded by the hottest material in the corona, and (3) that the dominance of one temperature versus the other is solar-cycle dependent.

  12. Solar thermal electric power plants - Their performance characteristics and total social costs

    Science.gov (United States)

    Caputo, R. S.; Truscello, V. C.

    1976-01-01

    The central receiver (power tower) concept as a thermal conversion approach to the conversion of solar energy into electricity is compared to other solar power plant designs which feature distributed solar collection and use other types of solar collector configurations. A variety of solar thermal storage concepts are discussed and their impacts on system performance are assessed. Although a good deal of quantification is possible in a comparative study, the subjective judgments carry enormous weight in a socio-economic decision, the ultimate choice of central power plant being more a social than an economic or technical decision. Major elements of the total social cost of each type of central plant are identified as utility economic costs, R&D funds, health costs, and other relevant social impacts.

  13. On the total variation dictionary model.

    Science.gov (United States)

    Zeng, Tieyong; Ng, Michael K

    2010-03-01

    The goal of this paper is to provide a theoretical study of a total variation (TV) dictionary model. Based on the properties of convex analysis and bounded variation functions, the existence of solutions of the TV dictionary model is proved. We then show that the dual form of the model can be given by the minimization of the sum of the l(1) -norm of the dual solution and the Bregman distance between the curvature of the primal solution and the subdifferential of TV norm of the dual solution. This theoretical result suggests that the dictionary must represent sparsely the curvatures of solution image in order to obtain a better denoising performance.

  14. Analysis of ionospheric irregularities during total solar eclipse 2016 based on GNSS observation

    Science.gov (United States)

    Husin, A.; Jiyo; Anggarani, S.; Ekawati, S.; Dear, V.

    2016-11-01

    A total solar eclipse occurred over Indonesia in the morning hours on 9 March 2016. Ionisations in the ionosphere which is associated with the solar radiation during the total eclipse provided a good opportunity to study the ionospheric irregularities. Using global navigation satellite system (GNSS) data taken from dual-frequency receivers in Manado, we investigated and analysed the total electron content (TEC) perturbations with a time resolution of 60 s to reveal ionospheric irregularities during total eclipse. Result showed that TEC conditions based on IPP were decreased during solar eclipse on March 9, comparing with the neighbour day. The maximum percentage deviation (DTEC) from the average value during eclipse period, 00:00 - 02:40 UT reach -41.5%. The duration of maximum decrement in TEC occurs were around 2-30 minutes after the maximum obscuration.

  15. Initial Results of Aperture Area Comparisons for Exo-Atmospheric Total Solar Irradiance Measurements

    Science.gov (United States)

    Johnson, B. Carol; Litorja, Maritoni; Fowler, Joel B.; Butler, James J.

    2009-01-01

    In the measurement of exo-atmospheric total solar irradiance (TSI), instrument aperture area is a critical component in converting solar radiant flux to irradiance. In a May 2000 calibration workshop for the Total Irradiance Monitor (TIM) on the Earth Observing System (EOS) Solar Radiation and Climate Experiment (SORCE), the solar irradiance measurement community recommended that NASA and NISI coordinate an aperture area measurement comparison to quantify and validate aperture area uncertainties and their overall effect on TSI uncertainties. From May 2003 to February 2006, apertures from 4 institutions with links to the historical TSI database were measured by NIST and the results were compared to the aperture area determined by each institution. The initial results of these comparisons are presented and preliminary assessments of the participants' uncertainties are discussed.

  16. Solar parameters for modeling interplanetary background

    CERN Document Server

    Bzowski, M; Tokumaru, M; Fujiki, K; Quemerais, E; Lallement, R; Ferron, S; Bochsler, P; McComas, D J

    2011-01-01

    The goal of the Fully Online Datacenter of Ultraviolet Emissions (FONDUE) Working Team of the International Space Science Institute in Bern, Switzerland, was to establish a common calibration of various UV and EUV heliospheric observations, both spectroscopic and photometric. Realization of this goal required an up-to-date model of spatial distribution of neutral interstellar hydrogen in the heliosphere, and to that end, a credible model of the radiation pressure and ionization processes was needed. This chapter describes the solar factors shaping the distribution of neutral interstellar H in the heliosphere. Presented are the solar Lyman-alpha flux and the solar Lyman-alpha resonant radiation pressure force acting on neutral H atoms in the heliosphere, solar EUV radiation and the photoionization of heliospheric hydrogen, and their evolution in time and the still hypothetical variation with heliolatitude. Further, solar wind and its evolution with solar activity is presented in the context of the charge excha...

  17. Space Based Observations of Coronal Cavities in Conjunction with the Total Solar Eclipse of July 2010

    Science.gov (United States)

    Kucera, T. A.; Berger, T. E.; Druckmuller, M.; Dietzel, M.; Gibson, S. E.; Habbal, S. R.; Morgan, H.; Reeves, K. K.; Schmit, D. J.; Seaton, D. B.

    2010-01-01

    In conjunction with the total solar eclipse on July 11, 2010 we coordinated a campaign between ground and space based observations. Our specific goal was to augment the ground based measurement of corona) prominence cavity temperatures made using iron lines in the IR (Habbal et al. 2010 ApJ 719 1362) with measurements performed by space based instruments. Included in the campaign were Hinode/EIS, XRT and SOT, PROBA2/SWAP, SDO/AIA, SOHO/CDS and STEREO/SECCHI/EUVI, in addition to the ground based IR measurements. We plan to use a combination of line ratio and forward modeling techniques to investigate the density and temperature structure of the cavities at that time.

  18. Development of meteorological parameters and total ozone during the total solar eclipse of August 11, 1999

    Directory of Open Access Journals (Sweden)

    Peter Winkler

    2001-05-01

    Full Text Available During the total eclipse of August 11, 1999 frequent showers occurred due to a unstable stratification of the air mass. At different observation sites, meteorological effects from the eclipse (99.4% coverage at Hohenpeißenberg and from showers were superimposed making it partly difficult to unambiguously interpret the observations. The weather radar at Hohenpeißenberg observatory provided a general overview of the distribution of clouds and precipitation in this area (200 km diameter. From the Garching site in the zone of totality (100% temperature and wind data taken on a 50 m mast were evaluated. By selecting periods with relatively low cloud cover it was possible to approximately follow the development of the vertical temperature and wind profiles during the eclipse. The minimum temperature at Hohenpeißenberg (about 450 m above the altitude of Garching during the eclipse was comparable to that during the previous night, the corresponding value measured at Garching remained about 2 K above the minimum observed during clear sky conditions in the previous night. Showers before, during or after the eclipse may have induced vertical exchange of air parcels. Temperatures during a shower change towards the same direction at all altitudes, thus no inversion forms. Additionally, air parcels with relatively lower concentrations of trace constituents were transported down from aloft for time periods of 10–15 minutes. These mixing processes significantly determined the temporal variations of various trace substances measured during the eclipse. Total ozone measurements at Hohenpeißenberg were performed with both DOBSON and BREWER spectrophotometers and at another site within the zone of totality by using a portable Microtops II filter instrument. Different results were obtained for both sites. These differences can be to a large extend, but not exclusively, attributed to eclipse induced shifts (limb darkening and straylight effects in the atmosphere

  19. An estimation of the total atmospheric pollution in Quetta (Pakistan) using solar data

    Energy Technology Data Exchange (ETDEWEB)

    Ilyas, Syed Z.; Nasir, S.M. [University of Balochistan, Group of Renewable Energy, Department of Physics, Quetta (Pakistan); Veziroglu, T.N. [University of Miami, Clean Energy Institute, Department of Mechanical Engineering, Miami, FL (United States)

    2007-11-15

    A new approach for the estimation of the total atmospheric pollution is suggested by using solar energy data. The dispersion of global solar radiation is relatively large during summer (June, July and August) and autumn (September, October, November) seasons for Quetta. A continuous relative attenuation of the order of 6-14% is due to presence of fine dust particles and pollutants throughout the year in the lower atmosphere at Quetta. Our results indicate an increased difference in the relative attenuation of global solar radiation for winter when compared with summer due to combustion of natural gas and mined coal for heating of buildings. (orig.)

  20. Wave Modeling of the Solar Wind.

    Science.gov (United States)

    Ofman, Leon

    The acceleration and heating of the solar wind have been studied for decades using satellite observations and models. However, the exact mechanism that leads to solar wind heating and acceleration is poorly understood. In order to improve the understanding of the physical mechanisms that are involved in these processes a combination of modeling and observational analysis is required. Recent models constrained by satellite observations show that wave heating in the low-frequency (MHD), and high-frequency (ion-cyclotron) range may provide the necessary momentum and heat input to coronal plasma and produce the solar wind. This review is focused on the results of several recent solar modeling studies that include waves explicitly in the MHD and the kinetic regime. The current status of the understanding of the solar wind acceleration and heating by waves is reviewed.

  1. Eclipse effects on field crops and marine zooplankton: the 29 March 2006 Total Solar Eclipse

    Directory of Open Access Journals (Sweden)

    G. Economou

    2008-01-01

    Full Text Available The effects in the biosphere from the Total Solar Eclipse of 29 March 2006 were investigated in field crops and marine zooplankton. Taking into account the decisive role of light on the photoenergetic and photoregulatory plant processes, measurements of photosynthesis and stomatal behaviour were conducted on seven important field-grown cereal and leguminous crops. A drop in photosynthetic rates, by more than a factor of 5 in some cases, was observed, and the minimum values of photosynthetic rates ranged between 3.13 and 10.13 μmol CO2 m−2 s−1. However, since solar irradiance attenuation has not at the same time induced stomatal closure thus not blocking CO2 uptake by plants, it is probably other endogenous factors that has been responsible for the observed fall in photosynthetic rates. Field studies addressing the migratory responses of marine zooplankton (micro-zooplankton (ciliates, and meso-zooplankton due to the rapid changes in underwater light intensity were also performed. The light intensity attenuation was simulated with the use of accurate underwater radiative transfer modeling techniques. Ciliates, responded to the rapid decrease in light intensity during the eclipse adopting night-time behaviour. From the meso-zooplankton assemblage, various vertical migratory behaviours were adopted by different species.

  2. Small-scale heating events in the solar atmosphere. II. Lifetime, total energy, and magnetic properties

    Science.gov (United States)

    Guerreiro, N.; Haberreiter, M.; Hansteen, V.; Schmutz, W.

    2017-07-01

    Context. Small-scale heating events (SSHEs) are believed to play a fundamental role in understanding the process responsible for heating of the solar corona, the pervading redshifts in the transition region, and the acceleration of spicules. Aims: We determine the properties of the SSHEs and the atmospheric response to them in 3D magnetohydrodynamics (3D-MHD) simulations of the solar atmosphere. Methods: We developed a method for identifying and following SSHEs over their lifetime, and applied it to two simulation models. We identified the locations where the energy dissipation is greatest inside the SSHEs volume, and we traced the SSHEs by following the spatial and temporal evolution of the maximum energy dissipation inside the SSHEs volume. Results: The method is effective in following the SSHEs. We can determine their lifetime, total energy, and properties of the plasma, as well as the magnetic field orientation in the vicinity of the SSHEs. Conclusions: We determine that the SSHEs that have the potential to heat the corona live less than 4 min, and typically the energy they release ranges from 1020 to 1024 erg. In addition, the directional change of the field lines on the two sides of the current sheet constituting the SSHEs ranges from 5° to 15° at the moment of the absolute maximum energy dissipation.

  3. Eclipse effects on field crops and marine zooplankton: the 29 March 2006 total solar eclipse

    Directory of Open Access Journals (Sweden)

    G. Economou

    2008-08-01

    Full Text Available Some effects in the biosphere from the Total Solar Eclipse of 29 March 2006 were investigated in field crops and marine zooplankton. Taking into account the decisive role of light on plant life and productivity, measurements of photosynthesis and stomatal behaviour were conducted on seven important field-grown cereal and leguminous crops. A drop in photosynthetic rates, by more than a factor of 5 in some cases, was observed, and the minimum values of photosynthetic rates ranged between 3.13 and 10.13 μmol CO2 m−2 s−1. The drop in solar irradiance and the increase in mesophyll CO2-concentration during the eclipse did not induce stomatal closure thus not blocking CO2 uptake by plants. Light effects on the photochemical phase of photosynthesis may be responsible for the observed depression in photosynthetic rates. Field studies addressing the migratory responses of marine zooplankton (micro-zooplankton (ciliates, and meso-zooplankton due to the rapid changes in underwater light intensity were also performed. The light intensity attenuation was simulated with the use of accurate underwater radiative transfer modeling techniques. Ciliates, responded to the rapid decrease in light intensity during the eclipse adopting night-time behaviour. From the meso-zooplankton assemblage, various vertical migratory behaviours were adopted by different species.

  4. Eclipse effects on field crops and marine zooplankton: the 29 March 2006 total solar eclipse

    Science.gov (United States)

    Economou, G.; Christou, E. D.; Giannakourou, A.; Gerasopoulos, E.; Georgopoulos, D.; Kotoulas, V.; Lyra, D.; Tsakalis, N.; Tzortziou, M.; Vahamidis, P.; Papathanassiou, E.; Karamanos, A.

    2008-08-01

    Some effects in the biosphere from the Total Solar Eclipse of 29 March 2006 were investigated in field crops and marine zooplankton. Taking into account the decisive role of light on plant life and productivity, measurements of photosynthesis and stomatal behaviour were conducted on seven important field-grown cereal and leguminous crops. A drop in photosynthetic rates, by more than a factor of 5 in some cases, was observed, and the minimum values of photosynthetic rates ranged between 3.13 and 10.13 μmol CO2 m-2 s-1. The drop in solar irradiance and the increase in mesophyll CO2-concentration during the eclipse did not induce stomatal closure thus not blocking CO2 uptake by plants. Light effects on the photochemical phase of photosynthesis may be responsible for the observed depression in photosynthetic rates. Field studies addressing the migratory responses of marine zooplankton (micro-zooplankton (ciliates), and meso-zooplankton) due to the rapid changes in underwater light intensity were also performed. The light intensity attenuation was simulated with the use of accurate underwater radiative transfer modeling techniques. Ciliates, responded to the rapid decrease in light intensity during the eclipse adopting night-time behaviour. From the meso-zooplankton assemblage, various vertical migratory behaviours were adopted by different species.

  5. A successful solar model using new solar composition data

    CERN Document Server

    Vagnozzi, Sunny; Zurbuchen, Thomas H

    2016-01-01

    A resolution is proposed to the "solar abundance problem", that is, the discrepancy between helioseismological observations and the predictions of solar models, computed implementing state-of-the-art photospheric abundances. We reassess the problem considering a newly determined set of abundances, which indicate a lower limit to the metallicity of $Z_{\\odot} = 0.0196 \\pm 0.0014$, significantly higher than findings during the past decade. Such value for the metallicity is determined in situ, measuring the least fractionated solar winds over the poles of the Sun, rather than spectroscopically. We determine the response of helioseismological observables to the corresponding changes in elemental abundances. Our findings indicate that, taking inversion errors into account, good agreement between models and observations is achieved. The definitive test for these abundances will be measurements of the CNO neutrino fluxes by SNO$^+$ (which we expect to be $\\sim$ 30-50\\% higher than predictions using abundances based ...

  6. Effect of March 9, 2016 Total Solar Eclipse on geomagnetic field variation

    Science.gov (United States)

    Ruhimat, Mamat; Winarko, Anton; Nuraeni, Fitri; Bangkit, Harry; Aris, M. Andi; Suwardi; Sulimin

    2016-11-01

    During solar eclipse, solar radiation to the Earth is blocked by the Moon. Thus, the ionization process in the ionosphere is disrupted, as well as the variation of geomagnetic field. The disturbance of geomagnetic field is caused by electric current in the E layer of the ionosphere. At low latitude, the current which is dominant in quiet day is the Sq currents. The blocking of solar radiation cause decrement in electron density in the blocked region. The aim of the research is to find the effect of total solar eclipse to the geomagnetic field. The measurement of the geomagnetic field variation during total solar eclipse on March 9, 2016 was carried out at the Meteorological station of BMKG in Ternate (0° 49' 45.20 "N; 127° 22' 54.00" E). By eliminating the geomagnetic disturbance that occurred in a daily geomagnetic field variation, the pattern of quiet day which is usually in a shape of smooth curve became affected. During the total solar eclipse on March 9, 2016 from 00:30 until 02:00 UT, we found that the geomagnetic field variation of the quiet day decreased by -5 nT.

  7. Standard solar model. II - g-modes

    Science.gov (United States)

    Guenther, D. B.; Demarque, P.; Pinsonneault, M. H.; Kim, Y.-C.

    1992-01-01

    The paper presents the g-mode oscillation for a set of modern solar models. Each solar model is based on a single modification or improvement to the physics of a reference solar model. Improvements were made to the nuclear reaction rates, the equation of state, the opacities, and the treatment of the atmosphere. The error in the predicted g-mode periods associated with the uncertainties in the model physics is predicted and the specific sensitivities of the g-mode periods and their period spacings to the different model structures are described. In addition, these models are compared to a sample of published observations. A remarkably good agreement is found between the 'best' solar model and the observations of Hill and Gu (1990).

  8. The analysis of solar models: Neutrinos and oscillations

    Science.gov (United States)

    Ulrich, R. K.; Rhodes, E. J., Jr.; Tomczyk, S.; Dumont, P. J.; Brunish, W. M.

    1983-01-01

    Tests of solar neutrino flux and solar oscillation frequencies were used to assess standard stellar structure theory. Standard and non-standard solar models are enumerated and discussed. The field of solar seismology, wherein the solar interior is studied from the measurement of solar oscillations, is introduced.

  9. Effects of total solar eclipse on mental patients-a clinicobiochemical correlation.

    Science.gov (United States)

    Boral, G C; Mishra, D C; Pal, S K; Ghosh, K K

    1981-04-01

    Thirteen treated psychotic cases comprising of eight schizophrenic, four M.D.P. (manic type) and one M. D. P. (depressive type), who were clinically symptom free, were studied in respect of their hormones and behavioural abnormalities under effect of total solar eclipse. Of the hormones studied viz., T(2), T(4), TSH, Cortisol and prolactin, it is prolactin which showed an increase in titre associated with behavioural abnormalities in concerned patients during and immediately after the total solar eclipse. Deflection in both prolactin and behaviour gradually seemed to normalise over the post eclipse period.

  10. Measurement of the Total Active 8B Solar Neutrino Flux at the Sudbury Neutrino Observatory with Enhanced Neutral Current Sensitivity

    CERN Document Server

    Ahmed, S N; Beier, E W; Bellerive, A; Biller, S D; Boger, J; Boulay, M G; Bowler, M G; Bowles, T J; Brice, S J; Bullard, T V; Chan, Y D; Chen, M; Chen, X; Cleveland, B T; Cox, G A; Dai, X; Dalnoki-Veress, F; Doe, P J; Dosanjh, R S; Doucas, G; Dragowsky, M R; Duba, C A; Duncan, F A; Dunford, M; Dunmore, J A; Earle, E D; Elliott, S R; Evans, H C; Ewan, G T; Farine, J; Fergani, H; Fleurot, F; Formaggio, J A; Fowler, M M; Frame, K; Fulsom, B G; Gagnon, N; Graham, K; Grant, D R; Hahn, R L; Hall, J C; Hallin, A L; Hallman, E D; Hamer, A S; Handler, W B; Hargrove, C K; Harvey, P J; Hazama, R; Heeger, K M; Heintzelman, W J; Heise, J; Helmer, R L; Hemingway, R J; Hime, A; Howe, M A; Jagam, P; Jelley, N A; Klein, J R; Kos, M S; Krumins, A V; Kutter, T; Kyba, C C M; Labranche, H; Lange, R; Law, J; Lawson, I T; Lesko, K T; Leslie, J R; Levine, I; Luoma, S; MacLellan, R; Majerus, S; Mak, H B; Maneira, J; Marino, A D; McCauley, N; McDonald, A B; McGee, S; McGregor, G; Miin, C; Miknaitis, K K S; Miller, G G; Moffat, B A; Nally, C W; Nickel, B G; Noble, A J; Norman, E B; Oblath, N S; Okada, C E; Ollerhead, R W; Orrell, J L; Oser, S M; Ouellet, C V; Peeters, S J M; Poon, A W P; Robertson, B C; Robertson, R G H; Rollin, E; Rosendahl, S S E; Rusu, V L; Schwendener, M H; Simard, O; Simpson, J J; Sims, C J; Sinclair, D; Skensved, P; Smith, M W E; Starinsky, N; Stokstad, R G; Stonehill, L C; Tafirout, R; Takeuchi, Y; Tesic, G; Thomson, M; Thorman, M; Van Berg, R; Van de Water, R G; Virtue, C J; Wall, B L; Waller, D; Waltham, C E; Wan Chan Tseung, H; Wark, D L; West, N; Wilhelmy, J B; Wilkerson, J F; Wilson, J R; Wouters, J M; Yeh, M; Zuber, K

    2004-01-01

    The Sudbury Neutrino Observatory (SNO) has precisely determined the total active (nu_x) 8B solar neutrino flux without assumptions about the energy dependence of the nu_e survival probability. The measurements were made with dissolved NaCl in the heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27 (stat) +/- 0.38 (syst) x10^6 cm^{-2}s^{-1}, in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Delta m^{2} = 7.1^{+1.2}_{-0.6}x10^{-5} ev^2 and theta = 32.5^{+2.4}_{-2.3} degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.

  11. Measurement of the total active 8B solar neutrino flux at the Sudbury Neutrino Observatory with enhanced neutral current sensitivity.

    Science.gov (United States)

    Ahmed, S N; Anthony, A E; Beier, E W; Bellerive, A; Biller, S D; Boger, J; Boulay, M G; Bowler, M G; Bowles, T J; Brice, S J; Bullard, T V; Chan, Y D; Chen, M; Chen, X; Cleveland, B T; Cox, G A; Dai, X; Dalnoki-Veress, F; Doe, P J; Dosanjh, R S; Doucas, G; Dragowsky, M R; Duba, C A; Duncan, F A; Dunford, M; Dunmore, J A; Earle, E D; Elliott, S R; Evans, H C; Ewan, G T; Farine, J; Fergani, H; Fleurot, F; Formaggio, J A; Fowler, M M; Frame, K; Fulsom, B G; Gagnon, N; Graham, K; Grant, D R; Hahn, R L; Hall, J C; Hallin, A L; Hallman, E D; Hamer, A S; Handler, W B; Hargrove, C K; Harvey, P J; Hazama, R; Heeger, K M; Heintzelman, W J; Heise, J; Helmer, R L; Hemingway, R J; Hime, A; Howe, M A; Jagam, P; Jelley, N A; Klein, J R; Kos, M S; Krumins, A V; Kutter, T; Kyba, C C M; Labranche, H; Lange, R; Law, J; Lawson, I T; Lesko, K T; Leslie, J R; Levine, I; Luoma, S; MacLellan, R; Majerus, S; Mak, H B; Maneira, J; Marino, A D; McCauley, N; McDonald, A B; McGee, S; McGregor, G; Mifflin, C; Miknaitis, K K S; Miller, G G; Moffat, B A; Nally, C W; Nickel, B G; Noble, A J; Norman, E B; Oblath, N S; Okada, C E; Ollerhead, R W; Orrell, J L; Oser, S M; Ouellet, C; Peeters, S J M; Poon, A W P; Robertson, B C; Robertson, R G H; Rollin, E; Rosendahl, S S E; Rusu, V L; Schwendener, M H; Simard, O; Simpson, J J; Sims, C J; Sinclair, D; Skensved, P; Smith, M W E; Starinsky, N; Stokstad, R G; Stonehill, L C; Tafirout, R; Takeuchi, Y; Tesić, G; Thomson, M; Thorman, M; Van Berg, R; Van de Water, R G; Virtue, C J; Wall, B L; Waller, D; Waltham, C E; Tseung, H Wan Chan; Wark, D L; West, N; Wilhelmy, J B; Wilkerson, J F; Wilson, J R; Wouters, J M; Yeh, M; Zuber, K

    2004-05-07

    The Sudbury Neutrino Observatory has precisely determined the total active (nu(x)) 8B solar neutrino flux without assumptions about the energy dependence of the nu(e) survival probability. The measurements were made with dissolved NaCl in heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27(stat)+/-0.38(syst) x 10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Deltam(2)=7.1(+1.2)(-0.6) x 10(-5) eV(2) and theta=32.5(+2.4)(-2.3) degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.

  12. Evidence of a long-term trend in total solar irradiance

    Science.gov (United States)

    Fröhlich, C.

    2009-07-01

    Aims: During the solar minimum of 2008, the value of total solar irradiance at 1 AU (TSI) was more than 0.2 Wm-2 lower than during the last minimum in 1996, indicating for the first time a directly observed long-term change. On the other hand, chromospheric indices and hence solar UV irradiance do not exhibit a similar change. Methods: Comparison of TSI with other activity parameters indicates that only the open solar magnetic field, BR, observed from satellites at 1 AU show a similar long-term behaviour. The values at the minima correlate well and the linear fit provides a direct physical relationship between TSI and BR during the minimum times. Results: This correlation allows an unambiguous reconstruction of TSI back in time, provided the open solar magnetic field can be determined from e.g. geomagnetic indices or cosmogenic radionucleides. Since the solar UV irradiance has no long-term trend, the mechanism for the secular change of TSI must differ from the effect of surface magnetism, as manifested by sunspots, faculae, and network which indeed explain well the intra-cycle variability of both total and spectral irradiance. Conclusions: The long-term trend of TSI is most probably caused by a global temperature change of the Sun that does not influence the UV irradiance in the same way as the surface magnetic fields. Appendix is only available in electronic form at http://www.aanda.org

  13. Global Solar Dynamo Models: Simulations and Predictions

    Indian Academy of Sciences (India)

    Mausumi Dikpati; Peter A. Gilman

    2008-03-01

    Flux-transport type solar dynamos have achieved considerable success in correctly simulating many solar cycle features, and are now being used for prediction of solar cycle timing and amplitude.We first define flux-transport dynamos and demonstrate how they work. The essential added ingredient in this class of models is meridional circulation, which governs the dynamo period and also plays a crucial role in determining the Sun’s memory about its past magnetic fields.We show that flux-transport dynamo models can explain many key features of solar cycles. Then we show that a predictive tool can be built from this class of dynamo that can be used to predict mean solar cycle features by assimilating magnetic field data from previous cycles.

  14. Broad band photometry of solar corona during the total solar eclipse of October 24, 1995.

    Science.gov (United States)

    Bagare, S. P.; Aleem, P. S. M.; Singh, J.; Saxena, A. K.

    A 30 cm coelostat, a red broad band filter, and a 15 cm objective providing an f/15 beam were used to obtain high resolution pictures of the white light solar corona. In one of the frames, the presence of a loop structure is recorded with its top around 2 Rsun, in the near north polar region. The nearest YOHKOH soft X-ray picture shows the presence of a coronal hole with its border apparently beneath the loop structure. The preliminary results are discussed.

  15. Extrapolating Solar Dynamo Models Throughout the Heliosphere

    Science.gov (United States)

    Cox, B. T.; Miesch, M. S.; Augustson, K.; Featherstone, N. A.

    2014-12-01

    There are multiple theories that aim to explain the behavior of the solar dynamo, and their associated models have been fiercely contested. The two prevailing theories investigated in this project are the Convective Dynamo model that arises from the pure solving of the magnetohydrodynamic equations, as well as the Babcock-Leighton model that relies on sunspot dissipation and reconnection. Recently, the supercomputer simulations CASH and BASH have formed models of the behavior of the Convective and Babcock-Leighton models, respectively, in the convective zone of the sun. These models show the behavior of the models within the sun, while much less is known about the effects these models may have further away from the solar surface. The goal of this work is to investigate any fundamental differences between the Convective and Babcock-Leighton models of the solar dynamo outside of the sun and extending into the solar system via the use of potential field source surface extrapolations implemented via python code that operates on data from CASH and BASH. The use of real solar data to visualize supergranular flow data in the BASH model is also used to learn more about the behavior of the Babcock-Leighton Dynamo. From the process of these extrapolations it has been determined that the Babcock-Leighton model, as represented by BASH, maintains complex magnetic fields much further into the heliosphere before reverting into a basic dipole field, providing 3D visualisations of the models distant from the sun.

  16. Modeling total expenditure on warranty claims

    CERN Document Server

    Mitra, Abhimanyu

    2010-01-01

    We approximate the distribution of total expenditure of a retail company over warranty claims incurred in a fixed period [0, T], say the following quarter. We consider two kinds of warranty policies, namely, the non-renewing free replacement warranty policy and the non-renewing pro-rata warranty policy. Our approximation holds under modest assumptions on the distribution of the sales process of the warranted item and the nature of arrivals of warranty claims. We propose a method of using historical data to statistically estimate the parameters of the approximate distribution. Our methodology is applied to the warranty claims data from a large car manufacturer for a single car model and model year.

  17. The 2016-2100 total solar eclipse prediction by using Meeus Algorithm implemented on MATLAB

    Science.gov (United States)

    Melati, A.; Hodijah, S.

    2016-11-01

    The phenomenon of solar and lunar eclipses can be predicted where and when it will happen. The Total Solar Eclipse (TSE) phenomenon on March 09th, 2016 became revival astronomy science in Indonesia and provided public astronomy education. This research aims to predict the total solar eclipse phenomenon from 2016 until 2100. We Used Besselian calculations and Meeus algorithms implemented in MATLAB R2012b software. This methods combine with VSOP087 and ELP2000-82 algorithm. As an example of simulation, TSE prediction on April 20th, 2042 has 0.2 seconds distinction of duration compared with NASA prediction. For the whole data TSE from year of 2016 until 2100 we found 0.04-0.21 seconds differences compared with NASA prediction.

  18. Dynamo Models of the Solar Cycle

    Directory of Open Access Journals (Sweden)

    Charbonneau Paul

    2005-06-01

    Full Text Available This paper reviews recent advances and current debates in modeling the solar cycle as a hydromagnetic dynamo process. Emphasis is placed on (relatively simple dynamo models that are nonetheless detailed enough to be comparable to solar cycle observations. After a brief overview of the dynamo problem and of key observational constraints, we begin by reviewing the various magnetic field regeneration mechanisms that have been proposed in the solar context. We move on to a presentation and critical discussion of extant solar cycle models based on these mechanisms. We then turn to the origin of fluctuations in these models, including amplitude and parity modulation, chaotic behavior, and intermittency. The paper concludes with a discussion of our current state of ignorance regarding various key questions, the most pressing perhaps being the identification of the physical mechanism(s responsible for the generation of the Sun's poloidal magnetic field component.

  19. First solar models with OPAS opacity tables

    CERN Document Server

    Pennec, Maëlle Le; Salmon, Sébastien; Blancard, Christophe; Cossé, Philippe; Faussurier, Gérald; Mondet, Guillaume

    2015-01-01

    Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However the particular case of Sun is still challenging. The helioseismic sound speed determination continues to disagree with the Standard Solar Model (SSM) prediction for about a decade, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this letter, we use the new OPAS opacity tables, recently available for solar modelling, to address this issue. We discuss first the peculiarities of these tables, then we quantify their impact on the solar sound speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes MESA and CLES that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models computed, for the most recent photosphe...

  20. Solar models, neutrino experiments, and helioseismology

    Science.gov (United States)

    Bahcall, John N.; Ulrich, Roger K.

    1988-01-01

    The event rates and their recognized uncertainties are calculated for 11 solar neutrino experiments using accurate solar models. These models are also used to evaluate the frequency spectrum of the p and g oscillations modes of the sun. It is shown that the discrepancy between the predicted and observed event rates in the Cl-37 and Kamiokande II experiments cannot be explained by a 'likely' fluctuation in input parameters with the best estimates and uncertainties given in the present study. It is suggested that, whatever the correct solution to the solar neutrino problem, it is unlikely to be a 'trival' error.

  1. The effect of total solar eclipse on the daily activities of Nasalis larvatus (Wurmb.) in Mangrove Center, Kariangau, East Kalimantan

    Science.gov (United States)

    Sya Shanida, Sya; Hanik Lestari, Tiffany; Partasasmita, Ruhyat

    2016-11-01

    The total solar eclipse is an interesting phenomenon because the sun is covered by the moon. This phenomenon is like a night deception for animals, humans, and plants. One of the animals is Bekantan (Nasalis larvatus (Wurmb.)). Nasalis larvatus change its activity when this phenomenon occurs. The aims of the present study are (1) daily activity of Nasalis larvatus on total solar eclipse on March 9th, 2016 and (2) the effect of total solar eclipse on its activity in Mangrove Center, Kariangau, East Kalimantan. The adlibitum method was used in this study on Bekantan's adult female. The result shows that the total solar eclipse has considerable effect on the daily activity of Bekantan. During total solar eclipse, the activity of Bekantan significantly stopped. When the total solar eclipse finished, Bekantan started its daily activity, and it was indicated by feeding activity which was led by alfa-male.

  2. Measurement of the total solar energy transmittance (g-value) for conventional glazings

    DEFF Research Database (Denmark)

    Duer, Karsten

    1998-01-01

    Three different glazings have been investigated in the Danish experimental setup METSET. (A device for calorimetric measurement of total solar energy transmittance - g-value).The purpose of the measurements is to increase the confidence in the calorimetric measurements. This is done by comparison...

  3. Stellar background observation during Total Solar Eclipse March 9th 2016

    Science.gov (United States)

    Mumtahana, Farahhati; Timur Jaelani, Anton; Muhamad, Johan; Sutastio, Heri

    2016-11-01

    We report observation and an early analysis of stellar background from total solar eclipse in Ternate, Indonesia. The eclipse phenomena which occurred on March, 9th 2016 was observed with certain portable instruments in order to obtain the stars behind the Sun in particular field of view and resolution. From our observation site in Ternate city, solar eclipse occurred in the late morning when the weather was unfortunately cloudy. However, during the darkness of totality, we obtained several point source objects between the gaps of the moving clouds and we suspected them as very faint stars due to their appearance in several frames. Those so called stars have been identified and measured with respect to their positions toward the center of the Sun. The main purpose of this research is to revisit strong lensing calculation of the Sun during total solar eclipse by measuring the deflection angle of the background stars as it had been calculated by Einstein and proved by Eddington at a total solar eclipse in 1919. To accomplish this aim, we need to conduct another observation to measure position of the same stars in the next period when those stars appear in the night sky.

  4. The observation of total solar eclipse in Indonesia on 11 June 1983.

    Science.gov (United States)

    Shimizu, Y.; Miyazaki, H.; Imai, H.; Hiei, E.

    The total solar eclipse on 11 June 1983 was observed at Cepu, Central Java. The planning, observing instruments, setting-up and the observing procedure are described. Electron number density in thread-like fine structures in an active region of the corona was derived to be about 5×109 from the corona taken at the eclipse.

  5. ACRIM-gap and total solar irradiance revisited: Is there a secular trend between 1986 and 1996?

    CERN Document Server

    Krivova, N A; Wenzler, T; 10.1029/2009GL040707

    2009-01-01

    A gap in the total solar irradiance (TSI) measurements between ACRIM-1 and ACRIM-2 led to the ongoing debate on the presence or not of a secular trend between the minima preceding cycles 22 (in 1986) and 23 (1996). It was recently proposed to use the SATIRE model of solar irradiance variations to bridge this gap. When doing this, it is important to use the appropriate SATIRE-based reconstruction, which we do here, employing a reconstruction based on magnetograms. The accuracy of this model on months to years timescales is significantly higher than that of a model developed for long-term reconstructions used by the ACRIM team for such an analysis. The constructed `mixed' ACRIM - SATIRE composite shows no increase in the TSI from 1986 to 1996, in contrast to the ACRIM TSI composite.

  6. The influences of solar radiation changes on the meteorological variables during the total solar eclipse of 9th March 2016 in Central Bangka, Indonesia

    Science.gov (United States)

    Gandini, Ryantika; Ardi, NanangDwi; Iid Mujtahiddin, M.

    2016-11-01

    Observations of the meteorological variables have been conducted in Terentang coastal area, Central Bangka which is located in totality path of Total Solar Eclipse on March 9, 2016. These measurements were made before, during, and after the solar eclipse using a portable automatic weather station with 1 Hz data recording to investigate the influence of total solar eclipse on the incoming solar radiation and other weather variables. Due to the cloudiness at the first phase of the eclipse, the reduction of the radiation was not proportional to the percentage of the solar obscuration. Along with the disappearance of thick clouds, solar radiation changes reach the lowest value from 123 W/m2 to zero point at 5 minutes before the maximum phase. In contrast to the radiation decrement, decreasing air temperature was not comparable to the solar obscuration because it was not only determined by radiation, but also surrounding environment. High relative humidity, on average 89%, was discovered as an effect of the low atmospheric pressure which was affected by the insolation decline. The effect of total solar eclipse can be seen more clearly with spectrum analysis using Fourier transformation to identify periodogram patterns of each meteorology variable. This transformation produced a spectrum's peak totality which is higher than before and after the event on the insolation. The spectrum represents that total solar eclipse has considerable effect to the incoming solar radiation and others which is indicated by the change of the amplitude.

  7. Comparison of Total Solar Irradiance with NASA/NSO Spectromagnetograph Data in Solar Cycles 22 and 23

    Science.gov (United States)

    Jones, Harrison P.; Branston, Detrick D.; Jones, Patricia B.; Popescu, Miruna D.

    2002-01-01

    An earlier study compared NASA/NSO Spectromagnetograph (SPM) data with spacecraft measurements of total solar irradiance (TSI) variations over a 1.5 year period in the declining phase of solar cycle 22. This paper extends the analysis to an eight-year period which also spans the rising and early maximum phases of cycle 23. The conclusions of the earlier work appear to be robust: three factors (sunspots, strong unipolar regions, and strong mixed polarity regions) describe most of the variation in the SPM record, but only the first two are associated with TSI. Additionally, the residuals of a linear multiple regression of TSI against SPM observations over the entire eight-year period show an unexplained, increasing, linear time variation with a rate of about 0.05 W m(exp -2) per year. Separate regressions for the periods before and after 1996 January 01 show no unexplained trends but differ substantially in regression parameters. This behavior may reflect a solar source of TSI variations beyond sunspots and faculae but more plausibly results from uncompensated non-solar effects in one or both of the TSI and SPM data sets.

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

    Science.gov (United States)

    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.

  9. Public Education Plans for the 2017 August 21 Total Solar Eclipse

    Science.gov (United States)

    Pasachoff, Jay M.

    2016-06-01

    A total solar eclipse will cross the continental United States on 2017 August 21, the first such in 99 years and the first whose path of totality on land is entirely in the United States since 1776. People in the rest of the United States-as well as in Canada, Central America, and northern South America-will have a partial solar eclipse. Totality will range up to about 70 km in diameter, and will be visible from a path that extends from Oregon to South Carolina. Cloudiness statistics based on decades on satellite infrared imaging are more favorable for western sites. The sun's diameter will be 80% covered in Miami (south of totality) and New York (north of totality), and 70% covered in Los Angeles (south of totality). For the Working Group on Solar Eclipses of the International Astronomical Union, I maintain a website at http://eclipses.info that provides links to a wide variety of eclipse-related material and to useful websites run by others.Prior to this total eclipse, annular eclipses will cross Africa (from Gabon to Tanzania and Madagascar) and Isle de la Réunion on 2016 September 1, and Chile and Argentina on 2017 February 26, at which time we plan an eclipse workshop in Esquel, Argentina.For the forthcoming 2017 eclipse, we acknowledge grants to JMP and Williams College from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation and from the Committee for Research and Exploration of the National Geographic Society.

  10. Total ozone column, aerosol optical depth and precipitable water effects on solar erythemal ultraviolet radiation recorded in Malta.

    Science.gov (United States)

    Bilbao, Julia; Román, Roberto; Yousif, Charles; Mateos, David; Miguel, Argimiro

    2013-04-01

    The Universities of Malta and Valladolid (Spain) developed a measurement campaign, which took place in the Institute for Energy Technology in Marsaxlokk (Southern Malta) between May and October 2012, and it was supported by the Spanish government through the Project titled "Measurement campaign about Solar Radiation, Ozone, and Aerosol in the Mediterranean area" (with reference CGL2010-12140-E). This campaign provided the first ground-based measurements in Malta of erythemal radiation and UV index, which indicate the effectiveness of the sun exposure to produce sunburn on human skin. A wide variety of instruments was involved in the campaign, providing a complete atmospheric characterization. Data of erythemal radiation and UV index (from UVB-1 pyranometer), total shortwave radiaton (global and diffuse components from CM-6B pyranometers), and total ozone column, aerosol optical thickness, and precitable water column (from a Microtops-II sunphotometer) were available in the campaign. Ground-based and satellite instruments were used in the analysis, and several intercomparisons were carried out to validate remote sensing data. OMI, GOME, GOME-2, and MODIS instruments, which provide data of ozone, aerosol load and optical properties, were used to this end. The effects on solar radiation, ultraviolet and total shortwave ranges, of total ozone column, aerosol optical thickness and precipitable water column were obtained using radiation measurements at different fixed solar zenith angles. The empirical results shown a determinant role of the solar position, a negligible effect of ozone on total shortwave radiation, and a stronger attenuation provided by aerosol particles in the erythemal radiation. A variety of aerosol types from different sources (desert dust, biomass burning, continental, and maritime) reach Malta, in this campaign several dust events from the Sahara desert occurred and were analyzed establishing the air mass back-trajectories ending at Malta at

  11. A New Generation of Standard Solar Models

    Science.gov (United States)

    Vinyoles, Núria; Serenelli, Aldo M.; Villante, Francesco L.; Basu, Sarbani; Bergström, Johannes; Gonzalez-Garcia, M. C.; Maltoni, Michele; Peña-Garay, Carlos; Song, Ningqiang

    2017-02-01

    We compute a new generation of standard solar models (SSMs) that includes recent updates on some important nuclear reaction rates and a more consistent treatment of the equation of state. Models also include a novel and flexible treatment of opacity uncertainties based on opacity kernels, required in light of recent theoretical and experimental works on radiative opacity. Two large sets of SSMs, each based on a different canonical set of solar abundances with high and low metallicity (Z), are computed to determine model uncertainties and correlations among different observables. We present detailed comparisons of high- and low-Z models against different ensembles of solar observables, including solar neutrinos, surface helium abundance, depth of the convective envelope, and sound speed profile. A global comparison, including all observables, yields a p-value of 2.7σ for the high-Z model and 4.7σ for the low-Z one. When the sound speed differences in the narrow region of 0.65< r/{R}ȯ < 0.70 are excluded from the analysis, results are 0.9σ and 3.0σ for high- and low-Z models respectively. These results show that high-Z models agree well with solar data but have a systematic problem right below the bottom of the convective envelope linked to steepness of molecular weight and temperature gradients, and that low-Z models lead to a much more general disagreement with solar data. We also show that, while simple parametrizations of opacity uncertainties can strongly alleviate the solar abundance problem, they are insufficient to substantially improve the agreement of SSMs with helioseismic data beyond that obtained for high-Z models due to the intrinsic correlations of theoretical predictions.

  12. Observing the 2017 Total Solar Eclipse from the Pisgah Astronomical Research Institute

    Science.gov (United States)

    Kirwan, Sean Matthew; Cline, J. Donald; Krochmal, Mark; Donald Cline, Mark Krochmal

    2017-01-01

    The Pisgah Astronomical Research Institute (PARI) is located directly under the path of totality of next year’s solar eclipse and possesses two 26m radio telescopes capable of interferometry at simultaneously at 2.3 GHz and 8.4 GHZ. PARI is preparing these radio telescopes for use by the astronomical community to observe solar eclipse. We will present the status of PARI’s radio telescopes and information on access for the eclipse. We will also present the status and availability of several optical telescopes.

  13. Utilisation of total solar radiation energy in the photosynthetic production of radish, red beet and bean

    Directory of Open Access Journals (Sweden)

    Wiesław Nowakowski

    2014-01-01

    Full Text Available Utilisation of total solar radiation energy in the photosynthetic production of radish, red beet and bean is expressed as per cent of solar radiation accumulated in the carbon of -the dry mass per 1 cm2 of the assimilation surface area. Utilisation of this energy ranges from 2.6 to 8.4 per cent in radish, from 1.7 to 7.5 per cent in beet and from 1.9 to 4.9 per cent in bean.

  14. Static and Dynamic Modeling of a Solar Active Region

    Science.gov (United States)

    Warren, Harry P.; Winebarger, Amy R.

    2007-09-01

    Recent hydrostatic simulations of solar active regions have shown that it is possible to reproduce both the total intensity and the general morphology of the high-temperature emission observed at soft X-ray wavelengths using static heating models. These static models, however, cannot account for the lower temperature emission. In addition, there is ample observational evidence that the solar corona is highly variable, indicating a significant role for dynamical processes in coronal heating. Because they are computationally demanding, full hydrodynamic simulations of solar active regions have not been considered previously. In this paper we make first application of an impulsive heating model to the simulation of an entire active region, AR 8156 observed on 1998 February 16. We model this region by coupling potential field extrapolations to full solutions of the time-dependent hydrodynamic loop equations. To make the problem more tractable we begin with a static heating model that reproduces the emission observed in four different Yohkoh Soft X-Ray Telescope (SXT) filters and consider impulsive heating scenarios that yield time-averaged SXT intensities that are consistent with the static case. We find that it is possible to reproduce the total observed soft X-ray emission in all of the SXT filters with a dynamical heating model, indicating that nanoflare heating is consistent with the observational properties of the high-temperature solar corona. At EUV wavelengths the simulated emission shows more coronal loops, but the agreement between the simulation and the observation is still not acceptable.

  15. Imaging and spectroscopic observations of the 9 March 2016 Total Solar Eclipse in Palangkaraya

    Science.gov (United States)

    Kholish, Abdul Majid Al; Jihad, Imanul; Taufik Andika, Irham; Puspitaningrum, Evaria; Ainy, Fathin Q.; Ramadhan, Sahlan; Ikbal Arifyanto, M.; Malasan, Hakim L.

    2016-11-01

    The March 9th 2016 total solar eclipse observation was carried out at Universitas Palangkaraya, Central Kalimantan. Time-resolved imaging of the Sun has been conducted before, after, and during totality of eclipse while optical spectroscopic observation has been carried out only at the totality. The imaging observation in white light was done to take high resolution images of solar corona. The images were taken with a DSLR camera that is attached to a refractor telescope (d=66 mm, f/5.9). Despite cloudy weather during the eclipse moments, we managed to obtain the images with lower signal-to-noise ratio, including identifiable diamond ring, prominence and coronal structure. The images were processed using standard reduction procedure to increase the signal-to-noise ratio and to enhance the corona. Then, the coronal structure is determined and compared with ultraviolet data from SOHO to analyze the correlation between visual and ultraviolet corona. The spectroscopic observation was conducted using a slit-less spectrograph and a DSLR camera to obtain solar flash spectra. The flash spectra taken during the eclipse show emissions of H 4861 Å, He I 5876 Å, and H 6563 Å. The Fe XIV 5303 Å and Fe X 6374 Å lines are hardly detected due to low signal-to-noise ratio. Spectral reduction and analysis are conducted to derive the emission lines intensity relative to continuum intensity. We use the measured parameters to determine the temperature of solar chromosphere.

  16. Detection of short period intensity oscillations in the solar corona observed during the total solar eclipse of august 11, 1999

    Directory of Open Access Journals (Sweden)

    R. Rezaei

    2005-03-01

    Full Text Available   An experiment to search for short-period intensity oscillations in the solar corona was conducted during the total solar eclipse of August 11, 1999 in Esfahan, Iran. The intensity in the continuum, centered about 4700 Å and with a passband having a half-width of 190 Å, was recorded at a counting rate of 5 Hz using six low-noise Hamamatsu R647 photomultiplier tubes. We recorded intensity values from 6 different regions on the image of the solar corona from 1.2 R ° to 1.5 R ° . The power spectrum analysis of all channels, except for a channel that failed to receive any coronal light, shows excess power in the frequency range 0.02-0.2 Hz. The results of analyzing all channels demonstrate various waves with some degree of coherence and amplitudes from 0.3 to 0.7 percent of the mean coronal brightness. There are some similarities between waves in various channels and it may show that these waves exist in a large region of the corona, of the order of a few hundred thousand kilometers, much larger than the fiber optic diaphragms. The energy flux of each wave was calculated by assuming them as the slow or fast mode waves for the active and quiet regions of the solar corona. The energy flux of the fast mode waves in the active regions is comparable with the required energy flux for heating up the solar corona. The intensity oscillations observed in this experiment are similar to those detected during the 1995 and 1997 eclipses.

  17. Hail risk model for solar collectors

    Science.gov (United States)

    Gonzalez, C.

    1978-01-01

    This report presents the results of a study assessing the probability of solar arrays being struck by hailstones of various sizes as a function of geographic location and service life. The study complements parallel studies of solar array sensitivity to hail damage, the final objective being an estimate of the most cost effective level for solar array hail protection. A key element of this study involves the generation of a statistical model describing the probability of impact by hailstones of various sizes and estimating the mean time between hits.

  18. Research of propagation the high frequency signals during total solar eclipses

    Science.gov (United States)

    Ryabova, Mariya; Ivanov, Vladimir; Ivanov, Dmitrii; Riabova, Natalia; Elsukov, Aleksei

    Vertical-oblique sounding methods are special importance for the study; they provide data on the electron concentration. In panoramic sounders, the mean frequencies of sounding signals vary consequently in the range of apriori uncertainty of the conditions of their reflection from the ionosphere. The aim of this work is the experimental study of the variations in the MUFs along one-hop HF lines during the total solar eclipses, and their application for the estimation of the effective recombination coefficient. To solve the above problem, experiments were carried out with the use of a chirp sounder manufactured at the Volga State University of Technology. The main advantages of chirp sounder are connected with the use of continuous chirps, which allow for the use of methods of optimal reception when deciphering in a frequency region, which provides for a signal-to-noise ratio acceptable for obtaining reliable results. We carried out experiments on oblique chirp sounding of the ionosphere during the total solar eclipse of March 29, 2006, and on the reference days of March 28 and 30, 2006, as well as during the total solar eclipse of August 1, 2008, and the reference days of July 31 and August 2, 2008. The ionosonde transmitters were located in Great Britain (the town of Inskip), Cyprus, and Irkutsk, and the receiver was located in Yoshkar-Ola. The maximal phases of the eclipse of March 29 at the target sounding point (TSP) were 0.89 for Cyprus-Yoshkar-Ola (observed at 11:15 UT) and 0.49 for Inskip-Yoshkar-Ola (observed at 11:03 UT); for the eclipse of August 1, 1 for Irkutsk-Yoshkar-Ola (observed at 11:36 UT). Based on the primary data (ionograms), the secondary data were determined in automatic mode. In particular, diurnal variations in the MUF of the 1F2 and 2F2 modes were calculated for the eclipse periods and the reference days along different radio paths. Variation in the MUF on the reference days required the use of a smoothing procedure, which was carried out

  19. Nanoflare heating model for collisionless solar corona

    Indian Academy of Sciences (India)

    U L VISAKH KUMAR; BILIN SUSAN VARGHESE; P J KURIAN

    2017-02-01

    The problem of coronal heating remains one of the greatest unresolved problems in space science. Magnetic reconnection plays a significant role in heating the solar corona. When two oppositely directed magnetic fields come closer to form a current sheet, the current density of the plasma increases due to which magnetic reconnection and conversion of magnetic energy into thermal energy takes place. The present paper deals with a model for reconnection occurring in the solar corona under steady state in collisionless regime. The model predicts that reconnection time in the solar corona varies inversely with the cube of magnetic field and varies directly with the Lindquist number. Our analysis shows that reconnections are occurring within a time interval of600 s in the solar corona, producing nanoflares in the energy range $10^{21}–10^{23}$ erg/s which matches with Yohkoh X-ray observations.

  20. Nanoflare heating model for collisionless solar corona

    Science.gov (United States)

    Visakh Kumar, U. L.; Varghese, Bilin Susan; Kurian, P. J.

    2017-02-01

    The problem of coronal heating remains one of the greatest unresolved problems in space science. Magnetic reconnection plays a significant role in heating the solar corona. When two oppositely directed magnetic fields come closer to form a current sheet, the current density of the plasma increases due to which magnetic reconnection and conversion of magnetic energy into thermal energy takes place. The present paper deals with a model for reconnection occurring in the solar corona under steady state in collisionless regime. The model predicts that reconnection time in the solar corona varies inversely with the cube of magnetic field and varies directly with the Lindquist number. Our analysis shows that reconnections are occurring within a time interval of 600 s in the solar corona, producing nanoflares in the energy range 10 21-10 23 erg /s which matches with Yohkoh X-ray observations.

  1. Solar irradiance models and measurements: a comparison in the 220 nm to 240 nm wavelength band

    CERN Document Server

    Unruh, Yvonne C; Krivova, Natalie A

    2011-01-01

    Solar irradiance models that assume solar irradiance variations to be due to changes in the solar surface magnetic flux have been successfully used to reconstruct total solar irradiance on rotational as well as cyclical and secular time scales. Modelling spectral solar irradiance is not yet as advanced, and also suffers from a lack of comparison data, in particular on solar-cycle time scales. Here we compare solar irradiance in the 220 nm to 240 nm band as modelled with SATIRE-S and measured by different instruments on the UARS and SORCE satellites. We find good agreement between the model and measurements on rotational time scales. The long-term trends, however, show significant differences. Both SORCE instruments, in particular, show a much steeper gradient over the decaying part of cycle 23 than the modelled irradiance or that measured by UARS/SUSIM.

  2. Corona during the total solar eclipse on March 20, 2015, and 24 cycle development

    Science.gov (United States)

    Yazev, Sergey; Mordvinov, Aleksandr; Dvorkina-Samarskaya, Antonina

    2016-06-01

    We analyzed the structure of coronal features, using data on the March 20, 2015 total solar eclipse. The Ludendorff index characterizing the flattening of the corona is 0.09. The solar corona structure in the Northern and Southern hemispheres corresponds to the maximum and post-maximum phases of solar activity, respectively. The asynchronous development of magnetic activity in the Sun's Northern and Southern hemispheres caused a substantial asymmetry of coronal features observed at the reversal of polar magnetic fields in the current cycle. The polar ray structures in the Southern Hemisphere are associated with the polar coronal hole, while in the Northern Hemisphere a polar hole has not been formed yet. We examine the relation between large-scale magnetic fields and location of high coronal structures.

  3. The Solar Variability and its Impact on Atmospheric NO2 Total amount

    Science.gov (United States)

    Kostadinov, Ivan; Werner, Rolf; Giovanelli, Giorgio; Petritoli, Andrea; Bortoli, Daniele; Atanasov, Atanas; Valev, Dimitare; Masieri, Samuele; Premuda, Margarita; Ravegnani, Fabrizio

    The solar electromagnetic output and irradiance is characterized by a large variability on dif-ferent time scales affecting entire Earth's climate system. Great efforts have been done by the scientific community to during the last decades to distinguish between natural and an-thropogenic features in climatic parameters variations. In this regard the monitoring of minor atmospheric constituents like NO2, which play key role in ozone and in nitrogen chemistry, provides useful information for better understanding of climate changes. By means of wavelet analysis we have analyzed available ground-based NO2 total column DOAS measurements from stations located in different geographical areas. The work concerns the short-term solar activity and NO2 column amount response. A significant cross-correlation is found between the solar activity and NO2 column amount at the time scale of the 27-days solar rotational cycle. The impact of long-term solar variability on NO2 trend is studied and the results are discussed.

  4. Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2013-09-01

    Full Text Available The variability of ionospheric response to the total solar eclipse of 22 July 2009 has been studied analyzing the GPS data recorded at the four Indian low-latitude stations Varanasi (100% obscuration, Kanpur (95% obscuration, Hyderabad (84% obscuration and Bangalore (72% obscuration. The retrieved ionospheric vertical total electron content (VTEC shows a significant reduction (reflected by all PRNs (satellites at all stations with a maximum of 48% at Varanasi (PRN 14, which decreases to 30% at Bangalore (PRN 14. Data from PRN 31 show a maximum of 54% at Kanpur and 26% at Hyderabad. The maximum decrement in VTEC occurs some time (2–15 min after the maximum obscuration. The reduction in VTEC compared to the quiet mean VTEC depends on latitude as well as longitude, which also depends on the location of the satellite with respect to the solar eclipse path. The amount of reduction in VTEC decreases as the present obscuration decreases, which is directly related to the electron production by the photoionization process. The analysis of electron density height profile derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere & Climate satellite over the Indian region shows significant reduction from 100 km altitude up to 800 km altitude with a maximum of 48% at 360 km altitude. The oscillatory nature in total electron content data at all stations is observed with different wave periods lying between 40 and 120 min, which are attributed to gravity wave effects generated in the lower atmosphere during the total solar eclipse.

  5. Micro-gravity measurements during the total solar eclipse of 9 March 2016 in Indonesia

    Science.gov (United States)

    Laesanpura, Agus; Hidayat, Taufiq; Abdurachman, Dady; Mahasena, Putra; Premadi, Premana W.; Wulandari, Hesti; Suharyadi, Yudi; Sjarmidi, Achmad

    2016-11-01

    Since 1950s, several authors have reported the so-called anomalous gravity during the total solar eclipses through various experiments. To address this issue, in the moment of the total solar eclipse of 9 March 2016 passing most regions in Indonesia, we undertook microgravity measurements using two precise gravimeters. The measurements were made at two locations: (1) Poso (central Sulawesi), a location close to the centre passage of the total eclipse and (2) Lembang (West Java), the site of Bosscha Observatory, where the partial solar eclipse occurred. The two sites are selected to measure the possible different influence of the eclipse on aligning the three objects. The measurements were recorded three days before and one day after the eclipse at various intervals from 30 seconds to a short time at 5 seconds. The finer recording was performed several hours before and after the total eclipse. This measurement allowed detailed analysis, not only in time but also in frequency range. A detailed analysis is presented in this paper. We consider all possible geophysical as well as atmospheric effects. The residual data show that the shielding effect, usually thought as responsible factor on anomalous gravity, is not significant.

  6. Satellite observations of surface temperature during the March 2015 total solar eclipse.

    Science.gov (United States)

    Good, Elizabeth

    2016-09-28

    The behaviour of remotely sensed land surface temperatures (LSTs) from the spinning-enhanced visible and infrared imager (SEVIRI) during the total solar eclipse of 20 March 2015 is analysed over Europe. LST is found to drop by up to several degrees Celcius during the eclipse, with the minimum LST occurring just after the eclipse mid-point (median=+1.5 min). The drop in LST is typically larger than the drop in near-surface air temperatures reported elsewhere, and correlates with solar obscuration (r=-0.47; larger obscuration = larger LST drop), eclipse duration (r=-0.62; longer duration = larger LST drop) and time (r=+0.37; earlier eclipse = larger LST drop). Locally, the LST drop is also correlated with vegetation (up to r=+0.6), with smaller LST drops occurring over more vegetated surfaces. The LSTs at locations near the coast and at higher elevation are also less affected by the eclipse. This study covers the largest area and uses the most observations of eclipse-induced surface temperature drops to date, and is the first full characterization of satellite LST during an eclipse (known to the author). The methods described could be applied to Geostationary Operational Environmental Satellite (GOES) LST data over North America during the August 2017 total solar eclipse.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.

  7. Solar energy estimation using REST2 model

    Directory of Open Access Journals (Sweden)

    M. Rizwan, Majid Jamil, D. P. Kothari

    2010-03-01

    Full Text Available The network of solar energy measuring stations is relatively rare through out the world. In India, only IMD (India Meteorological Department Pune provides data for quite few stations, which is considered as the base data for research purposes. However, hourly data of measured energy is not available, even for those stations where measurement has already been done. Due to lack of hourly measured data, the estimation of solar energy at the earth’s surface is required. In the proposed study, hourly solar energy is estimated at four important Indian stations namely New Delhi, Mumbai, Pune and Jaipur keeping in mind their different climatic conditions. For this study, REST2 (Reference Evaluation of Solar Transmittance, 2 bands, a high performance parametric model for the estimation of solar energy is used. REST2 derivation uses the two-band scheme as used in the CPCR2 (Code for Physical Computation of Radiation, 2 bands but CPCR2 does not include NO2 absorption, which is an important parameter for estimating solar energy. In this study, using ground measurements during 1986-2000 as reference, a MATLAB program is written to evaluate the performance of REST2 model at four proposed stations. The solar energy at four stations throughout the year is estimated and compared with CPCR2. The results obtained from REST2 model show the good agreement against the measured data on horizontal surface. The study reveals that REST2 models performs better and evaluate the best results as compared to the other existing models under cloudless sky for Indian climatic conditions.

  8. NeQuick 2 total electron content predictions for middle latitudes of North American region during a deep solar minimum

    Science.gov (United States)

    Ezquer, R. G.; Scidá, L. A.; Migoya Orué, Y. O.; Lescano, G. E.; Alazo-Cuartas, K.; Cabrera, M. A.; Radicella, S. M.

    2017-02-01

    The performance of NeQuick 2 model in computing the vertical total electron content (VTEC) over a wide region placed at middle latitudes of North America during the deep solar minimum that occurred in 2008 has been checked. The long term relationship between EUV irradiance and F10.7 solar flux has changed markedly during the cycle 23/24 minimum with EUV levels decreasing more than expected from F10.7 proxy. A decrease of ionization in the ionosphere could have occurred. Thus, it could be expected that the models overestimate the value of ionospheric parameters for that deep solar minimum. For this study a high density VTEC data grid that covers the Continental United States (CONUS) has been compared with monthly median maps constructed with NeQuick 2. The results show that NeQuick 2 generally gives good predictions for the region which lies between 35°N to 50°N suggesting that nothing exceptional was happening during the 2008 minimum in terms of VTEC NeQuick 2's predictive capabilities. Taking into account that the modeled value is obtained by integration in height of the electron density profile, NeQuick2 would be assuming an inadequate profile for the few highest deviations observed, between 30°N and 35°N. Overall, the model does not give significant overestimation of VTEC as could be expected.

  9. Zenith skylight intensity and color during the total solar eclipse of 20 July 1963.

    Science.gov (United States)

    Sharp, W E; Lloyd, J W; Silverman, S M

    1966-05-01

    The zenith skylight intensity was measured, with a resolution of 10 A, over the wavelength range from 5200 A to 6400 A during a total solar eclipse at Hermon, Maine. The intensity was found to change by about two orders of magnitude in the 2-min period before totality and reached a minimum during totality of 19.5 kR/A at 5200 A. The spectral distribution remained that of the day sky until the sun was more than 99.8% obscured. During totality, the shorter wavelengths were enhanced, indicating a shift to the blue in sky color. Comparisons with an independent measurement from an aircraft show that the intensity scale height of the secondary scattered component, predominating at totality, is significantly less than that of the day sky. The measurements are compared with the day and twilight sky.

  10. Exploring the Physics of the Corona with Total Solar Eclipse Observations

    OpenAIRE

    2011-01-01

    This white paper is a call for a concerted effort to support total solar eclipse observations over the next decade, in particular for the 21 August 2017 eclipse which will traverse the US continent. With the recent advances in image processing techniques and detector technology, the time is ripe to capitalize on the unique diagnostic tools available in the visible and near infrared wavelength range to explore the physics of the corona. The advantage of coronal emission lines in this wavelengt...

  11. Solar total energy: large scale experiment, Shenandoah, Georgia Site. Annual report, June 1978-June 1979

    Energy Technology Data Exchange (ETDEWEB)

    Ney, E.J.

    1979-07-01

    A background summary and a complete description of the progress and current status of activities relative to the Cooperative Agreement for the Solar Total Energy - Large Scale Experiment at the Bleyle Knitwear Plant at Shenandoah, Georgia are presented. A statement of objectives and an abstract of progress to date are included. This is followed by a short introduction containing a project overview, a summary of the participants and their respective roles, a brief description of the Solar Total Energy System (STES) design concept, and a chronological summary of progress to date. A general description of the site is given, a detailed report of progress is reported, and drawings and equipment lists are included. The closed-loop solar energy system planned for Shenandoah begins with circulation of Syltherm 800, a heat transfer fluid of the Dow-Corning Corporation, through the receiver tubes of a parabolic dish solar collector field. As solar energy is focused on the receivers, the heat transfer fluid is heated to approximately 399/sup 0/C (750/sup 0/F) and is pumped to a heat exchanger for immediate use, or to a thermal storage system for later use. Once in the heat exchanger, the fluid heats a working fluid that produces the steam required for operating the turbine. After performing this task, the heat transfer fluid returns to the collectors to repeat the cycle, while the steam turbine-generator system supplies the electrical demands for the knitwear plant and the STES. During STES operation, maximum thermal and electrical requirements of the application are expected to be at 1.08 MWth and 161 kWe, respectively. During the power generation phase, some of the steam is extracted for use as process steam in the knitwear manufacturing process, while exhaust steam from the turbine is passed through a condenser to produce hot water for heating, domestic use, and absorption air conditioning. (WHK)

  12. The Assembled Solar Eclipse Package (ASEP) in Bangka Indonesia during the total solar eclipse on March 9, 2016

    Science.gov (United States)

    Puji Asmoro, Cahyo; Wijaya, Agus Fany Chandra; Dwi Ardi, Nanang; Abdurrohman, Arman; Aria Utama, Judhistira; Sutiadi, Asep; Hikmat; Ramlan Ramalis, Taufik; Suyardi, Bintang

    2016-11-01

    The Assembled Solar Eclipse Package (ASEP) is not only an integrated apparatus constructed to obtain imaging data during solar eclipse, but also it involved sky brightness and live streaming requirement. Main four parts of ASEP are composed by two imaging data recorders, one high definition video streaming camera, and a sky quality meter instrument (SQM) linked by a personal computer and motorized mounting. The parts are common instruments which are used for education or personal use. The first part is used to capture corona and prominence image during totality. For the second part, video is powerful data in order to educate public through web streaming lively. The last part, SQM is used to confirm our imaging data during obscuration. The perfect prominence picture was obtained by one of the data capture using William-Optics F=388mm with Nikon DSLR D3100. In addition, the diamond ring and corona were recorded by the second imaging tool using Sky Watcher F=910mm with Canon DSLR 60D. The third instrument is the Sony HXR MC5 streaming set to be able to broadcast to public domain area via official website. From the SQM, the value of the darkness during totality is quiet similar as a dawn condition. Finally, ASEP was entirely successful and be able to fulfil our competency as educational researcher in university.

  13. Reconstruction of total and spectral solar irradiance from 1974 to 2013 based on KPVT, SoHO/MDI and SDO/HMI observations

    CERN Document Server

    Yeo, K L; Solanki, S K; Glassmeier, K H

    2014-01-01

    Total and spectral solar irradiance are key parameters in the assessment of solar influence on changes in the Earth's climate. We present a reconstruction of daily solar irradiance obtained using the SATIRE-S model spanning 1974 to 2013 based on full-disc observations from the KPVT, SoHO/MDI and SDO/HMI. SATIRE-S ascribes variation in solar irradiance on timescales greater than a day to photospheric magnetism. The solar spectrum is reconstructed from the apparent surface coverage of bright magnetic features and sunspots in the daily data using the modelled intensity spectra of these magnetic structures. We cross-calibrated the various data sets, harmonizing the model input so as to yield a single consistent time series as the output. The model replicates $92\\%$ of the variability in the PMOD TSI composite including the secular decline between the 1996 and 2008 solar cycle minima. The model also reproduces most of the variability in observed Lyman-alpha irradiance and the Mg II index. The UV solar irradiance m...

  14. More solar models and neutrino fluxes.

    Science.gov (United States)

    Abraham, Z.; Iben, I., Jr.

    1971-01-01

    Derivation of neutrino fluxes from a sequence of solar models that differ from one another in regard to opacity, equation of state, and nuclear cross-section factors. Using current estimates of the relevant input parameters, capture rates are obtained that range between three and ten times the most recent result of the Davis Cl 37 neutrino-capture experiment. The contribution to a theoretical capture rate due to neutrinos from all reactions other than B 8 decay ranges from 0.5 to 1.5 times the latest observational result. Comparison with results of other solar model calculations indicates reasonable agreement when results are normalized to the same input parameters.

  15. Total solar irradiance as measured by the SOVAP radiometer onboard PICARD

    Directory of Open Access Journals (Sweden)

    Meftah Mustapha

    2016-01-01

    Full Text Available From the SOlar VAriability PICARD (SOVAP space-based radiometer, we obtained a new time series of the total solar irradiance (TSI during Solar Cycle 24. Based on SOVAP data, we obtained that the TSI input at the top of the Earth’s atmosphere at a distance of one astronomical unit from the Sun is 1361.8 ± 2.4 W m−2 (1σ representative of the 2008 solar minimum period. From 2010 to 2014, the amplitude of the changes has been of the order of ± 0.1%, corresponding to a range of about 2.7 W m−2. To determine the TSI from SOVAP, we present here an improved instrument equation. A parameter was integrated from a theoretical analysis that highlighted the thermo-electrical non-equivalence of the radiometric cavity. From this approach, we obtained values that are lower than those previously provided with the same type of instrument. The results in this paper supersede the previous SOVAP analysis and provide the best SOVAP-based TSI-value estimate and its temporal variation.

  16. Total solar irradiance as measured by the SOVAP radiometer onboard PICARD

    Science.gov (United States)

    Meftah, Mustapha; Chevalier, André; Conscience, Christian; Nevens, Stijn

    2016-09-01

    From the SOlar VAriability PICARD (SOVAP) space-based radiometer, we obtained a new time series of the total solar irradiance (TSI) during Solar Cycle 24. Based on SOVAP data, we obtained that the TSI input at the top of the Earth's atmosphere at a distance of one astronomical unit from the Sun is 1361.8 ± 2.4 W m-2 (1σ) representative of the 2008 solar minimum period. From 2010 to 2014, the amplitude of the changes has been of the order of ± 0.1%, corresponding to a range of about 2.7 W m-2. To determine the TSI from SOVAP, we present here an improved instrument equation. A parameter was integrated from a theoretical analysis that highlighted the thermo-electrical non-equivalence of the radiometric cavity. From this approach, we obtained values that are lower than those previously provided with the same type of instrument. The results in this paper supersede the previous SOVAP analysis and provide the best SOVAP-based TSI-value estimate and its temporal variation.

  17. SOLINS- SOLAR INSOLATION MODEL FOR COMPUTING AVAILABLE SOLAR ENERGY TO A SURFACE OF ARBITRARY ORIENTATION

    Science.gov (United States)

    Smith, J. H.

    1994-01-01

    This computer program, SOLINS, was developed to aid engineers and solar system designers in the accurate modeling of the average hourly solar insolation on a surface of arbitrary orientation. The program can be used to study insolation problems specific to residential and commercial applications where the amount of space available for solar collectors is limited by shadowing problems, energy output requirements, and costs. For tandem rack arrays, SOLINS will accommodate the use of augmentation reflectors built into the support structure to increase insolation values at the collector surface. As the use of flat plate solar collectors becomes more prevalent in the building industry, the engineer and designer must have the capability to conduct extensive sensitivity analyses on the orientation and location of solar collectors. SOLINS should prove to be a valuable aid in this area of engineering. SOLINS uses a modified version of the National Bureau of Standards model to calculate the direct, diffuse, and reflected components of total insolation on a tilted surface with a given azimuthal orientation. The model is based on the work of Liu and Jordan with corrections by Kusuda and Ishii to account for early morning and late afternoon errors. The model uses a parametric description of the average day solar climate to generate monthly average day profiles by hour of the insolation level on the collector surface. The model includes accommodation of user specified ground and landscape reflectivities at the collector site. For roof or ground mounted, tilted arrays, SOLINS will calculate insolation including the effects of shadowing and augmentation reflectors. The user provides SOLINS with data describing the array design, array orientation, the month, the solar climate parameter, the ground reflectance, and printout control specifications. For the specified array and environmental conditions, SOLINS outputs the hourly insolation the array will receive during an average day

  18. Ionospheric response to the total solar eclipse of June 21, 2001

    CERN Document Server

    Afraimovich, E L

    2002-01-01

    We discuss the measurements of the main parameters of the ionospheric response to the total solar eclipse of June 21, 2001. This study is based on using the data from three stations of the global GPS network located in the area of the totality band in Africa. This period was characterized by a low level of geomagnetic disturbance (the Dst-index varied from -6 to 22 nT), which alleviated greatly the problem of detecting the ionospheric response to eclipse. An analysis revealed a clearly pronounced effect of a decrease (depression) of the total electron content (TEC) for all GPS stations. The delay between the smallest value of the TEC with respect to eclipse totality was 9-37 min. The depth and duration of the TEC depression were 0.5-0.9 TECU and 30-67 min, respectively. The results obtained in this study are in good agreement with earlier measurements and theoretical estimations.

  19. Measurement of the νe and total 8B solar neutrino fluxes with the Sudbury Neutrino Observatory phase-III data set

    Science.gov (United States)

    Aharmim, B.; Ahmed, S. N.; Amsbaugh, J. F.; Anaya, J. M.; Anthony, A. E.; Banar, J.; Barros, N.; Beier, E. W.; Bellerive, A.; Beltran, B.; Bergevin, M.; Biller, S. D.; Boudjemline, K.; Boulay, M. G.; Bowles, T. J.; Browne, M. C.; Bullard, T. V.; Burritt, T. H.; Cai, B.; Chan, Y. D.; Chauhan, D.; Chen, M.; Cleveland, B. T.; Cox, G. A.; Currat, C. A.; Dai, X.; Deng, H.; Detwiler, J. A.; DiMarco, M.; Doe, P. J.; Doucas, G.; Dragowsky, M. R.; Drouin, P.-L.; Duba, C. A.; Duncan, F. A.; Dunford, M.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Fleurot, F.; Ford, R. J.; Formaggio, J. A.; Fowler, M. M.; Gagnon, N.; Germani, J. V.; Goldschmidt, A.; Goon, J. TM.; Graham, K.; Guillian, E.; Habib, S.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamian, A. A.; Harper, G. C.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Henning, R.; Hime, A.; Howard, C.; Howe, M. A.; Huang, M.; Jagam, P.; Jamieson, B.; Jelley, N. A.; Keeter, K. J.; Klein, J. R.; Kormos, L. L.; Kos, M.; Krüger, A.; Kraus, C.; Krauss, C. B.; Kutter, T.; Kyba, C. C. M.; Lange, R.; Law, J.; Lawson, I. T.; Lesko, K. T.; Leslie, J. R.; Loach, J. C.; MacLellan, R.; Majerus, S.; Mak, H. B.; Maneira, J.; Martin, R.; McCauley, N.; McDonald, A. B.; McGee, S. R.; Mifflin, C.; Miller, G. G.; Miller, M. L.; Monreal, B.; Monroe, J.; Morissette, B.; Myers, A. W.; Nickel, B. G.; Noble, A. J.; O'Keeffe, H. M.; Oblath, N. S.; Ollerhead, R. W.; Orebi Gann, G. D.; Oser, S. M.; Ott, R. A.; Peeters, S. J. M.; Poon, A. W. P.; Prior, G.; Reitzner, S. D.; Rielage, K.; Robertson, B. C.; Robertson, R. G. H.; Rollin, E.; Schwendener, M. H.; Secrest, J. A.; Seibert, S. R.; Simard, O.; Simpson, J. J.; Skensved, P.; Smith, M. W. E.; Sonley, T. J.; Steiger, T. D.; Stonehill, L. C.; Tešić, G.; Thornewell, P. M.; Tolich, N.; Tsui, T.; Tunnell, C. D.; Van Wechel, T.; Van Berg, R.; VanDevender, B. A.; Virtue, C. J.; Wall, B. L.; Waller, D.; Wan Chan Tseung, H.; Wendland, J.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J. R.; Wouters, J. M.; Wright, A.; Yeh, M.; Zhang, F.; Zuber, K.

    2013-01-01

    This paper details the solar neutrino analysis of the 385.17-day phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of 3He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. This technique to determine the total active 8B solar neutrino flux was largely independent of the methods employed in previous phases. The total flux of active neutrinos was measured to be 5.54-0.31+0.33(stat.)-0.34+0.36(syst.)×106 cm-2 s-1, consistent with previous measurements and standard solar models. A global analysis of solar and reactor neutrino mixing parameters yielded the best-fit values of Δm2=7.59-0.21+0.19×10-5eV2 and θ=34.4-1.2+1.3degrees.

  20. Global MHD Models of the Solar Corona

    Science.gov (United States)

    Suess, S. T.; Rose, Franklin (Technical Monitor)

    2001-01-01

    Global magnetohydrodynamic (MHD) models of the solar corona are computationally intensive, numerically complex simulations that have produced important new results over the past few years. After a brief overview of how these models usually work, I will address three topics: (1) How these models are now routinely used to predict the morphology of the corona and analyze Earth and space-based remote observations of the Sun; (2) The direct application of these models to the analysis of physical processes in the corona and chromosphere and to the interpretation of in situ solar wind observations; and (3) The use of results from global models to validate the approximations used to make detailed studies of physical processes in the corona that are not otherwise possible using the global models themselves.

  1. A new Generation of Standard Solar Models

    CERN Document Server

    Vinyoles, Núria; Villante, Francesco L; Basu, Sarbani; Bergström, Johannes; Gonzalez-Garcia, M C; Maltoni, Michele; Peña-Garay, Carlos; Song, Ningqiang

    2016-01-01

    We compute a new generation of standard solar models (SSMs) that includes recent updates on some important nuclear reaction rates and a more consistent treatment of the equation of state. Models also include a novel and flexible treatment of opacity uncertainties based on opacity kernels, required in the light of recent theoretical and experimental works on radiative opacity. Two large sets of SSMs, each based on a different canonical set of solar abundances with high and low metallicity (Z), are computed to determine model uncertainties and correlations among different observables. We present detailed comparisons of high- and low-Z models against different ensembles of solar observables including solar neutrinos, surface helium abundance, depth of convective envelope and sound speed profile. A global comparison, including all observables, yields a p-value of 2.7$\\sigma$ for the high-Z model and 4.7$\\sigma$ for the low-Z one. When the sound-speed differences in the narrow region of $0.65 < r/R_{sun} < 0...

  2. Effects on surface atmospheric photo-oxidants over Greece during the total solar eclipse event of 29 March 2006

    Directory of Open Access Journals (Sweden)

    P. Zanis

    2007-08-01

    Full Text Available This study investigates the effects of the total solar eclipse of 29 March 2006 on surface air-quality levels over Greece based on observations at a number of sites in conjunction with chemical box modelling and 3-D air-quality modelling. Emphasis is given on surface ozone and other photooxidants at four Greek sites Kastelorizo, Finokalia (Crete, Pallini (Athens and Thessaloniki, which are located at gradually increasing distances from the path of the eclipse totality and are characterized by different air pollution levels. The eclipse offered the opportunity to test our understanding of air pollution build-up and the response of the gas-phase chemistry of photo-oxidants during a photolytical perturbation using both a photochemical box model and a regional air-quality offline model based on the modeling system WRF/CAMx. At the relatively unpolluted sites of Kastelorizo and Finokalia no clear impact of the solar eclipse on surface O3, NO2 and NO concentrations can be deduced from the observations and model simulations as the calculated changes in net ozone production rates between eclipse and non eclipse conditions are rather small compared to the ozone variability and hence the solar eclipse effects on ozone can be easily masked by transport. At the polluted sites of Thessaloniki and Pallini, the solar eclipse effects on O3, NO2 and NO concentrations are clearly revealed from both the measurements and 3-D air-quality modeling with the net effect being a decrease in O3 and NO and an increase in NO2 as NO2 formed from the reaction of O3 with NO while at the same time NO2 is not efficiently photolysed. It is evident from the 3-D air quality modeling over Greece that the maximum effects of the eclipse on O3, NO2 and NO are reflected at the large urban agglomerations of Athens, and Thessaloniki where the maximum of the emissions

  3. Effects on surface atmospheric photo-oxidants over Greece during the total solar eclipse event of 29 March 2006

    Directory of Open Access Journals (Sweden)

    P. Zanis

    2007-12-01

    Full Text Available This study investigates the effects of the total solar eclipse of 29 March 2006 on surface air-quality levels over Greece based on observations at a number of sites in conjunction with chemical box modelling and 3-D air-quality modelling. Emphasis is given on surface ozone and other photooxidants at four Greek sites Kastelorizo, Finokalia (Crete, Pallini (Athens and Thessaloniki, which are located at gradually increasing distances from the path of the eclipse totality and are characterized by different air pollution levels. The eclipse offered the opportunity to test our understanding of air pollution build-up and the response of the gas-phase chemistry of photo-oxidants during a photolytical perturbation using both a photochemical box model and a regional air-quality offline model based on the modeling system WRF/CAMx. At the relatively unpolluted sites of Kastelorizo and Finokalia no clear signal of the solar eclipse on surface O3, NO2 and NO concentrations can be deduced from the observations while there is no correlation of observed O3, NO2 and NO with observed global radiation. The box and regional model simulations for the two relatively unpolluted sites indicate that the calculated changes in net ozone production rates between eclipse and non eclipse conditions are rather small compared to the observed short-term ozone variability. Furthermore the simulated ozone lifetime is in the range of a few days at these sites and hence the solar eclipse effects on ozone can be easily masked by local and regional transport. At the polluted sites of Thessaloniki and Pallini, the solar eclipse effects on O3, NO2 and NO concentrations are revealed from both the measurements and modeling with the net effect being a decrease in O3 and NO and an increase in NO2 as NO2 formed from the reaction of O3 with NO while at the same time NO2 is

  4. Exploring the Physics of the Corona with Total Solar Eclipse Observations

    CERN Document Server

    Habbal, Shadia R; Daw, Adrian; Ding, Adalbert; Druckmuller, Miloslav; Esser, Ruth; Johnson, Judd; Morgan, Huw

    2011-01-01

    This white paper is a call for a concerted effort to support total solar eclipse observations over the next decade, in particular for the 21 August 2017 eclipse which will traverse the US continent. With the recent advances in image processing techniques and detector technology, the time is ripe to capitalize on the unique diagnostic tools available in the visible and near infrared wavelength range to explore the physics of the corona. The advantage of coronal emission lines in this wavelength range, over their extreme ultraviolet counterparts, is (1) the significant radiative component in their excitation process (in addition to the collisional excitation), which allows for observations out to a few solar radii, (2) the higher spectral selectivity available for imaging, giving well-defined temperature responses for each bandpass (one line as opposed to many), and (3) the capability of polarization measurements in a number of spectral lines. Consequently, the evolution of the thermodynamic and magnetic proper...

  5. Effect of the total solar eclipse of March 20, 2015, on VLF/LF propagation

    Science.gov (United States)

    Solovieva, M. S.; Rozhnoi, A. A.; Fedun, V.; Schwingenschuh, K.

    2016-05-01

    The analyzed amplitude and phase variations in electromagnetic VLF and LF signals at 20-45 kHz, received in Moscow, Graz (Austria), and Sheffield (UK) during the total solar eclipse of March 20, 2015, are considered. The 22 analyzed paths have lengths of 200—6100 km, are differently oriented, and cross 40-100% occultation regions. Fifteen paths crossed the region where the occultation varied from 40 to 90%. Solar eclipse effects were found only on one of these paths in the signal phase (-50°). Four long paths crossed the 90-100% occultation region, and signal amplitude and phase anomalies were detected for all four paths. Negative phase anomalies varied from-75° to-90°, and the amplitude anomalies were both positive and negative and were not larger than 5 dB. It was shown that the effective height of the ionosphere varied from 6.5 to 11 km during the eclipse.

  6. First Report on the 2016 March 9 Total Solar Eclipse Observations

    Science.gov (United States)

    Pasachoff, Jay M.

    2016-06-01

    Totality swept across Indonesia and into the Pacific on 2016 March 9, lasting up to 2 min 45 s on Ternate in the Spice Islands (Malukus). I provide a first report on our observations. Our scientific goal is to follow changes in the corona over the solar-activity cycle, now past its 2012 and 2014 double peak, and to measure temporal changes in the corona on the scale of minutes or hours by comparing eclipse observations made at several sites along the path. I also discuss the near-simultaneous coronal observations made with SOHO/LASCO, SDO/AIA, STEREO/SECCHI, PROBA2/SWAP, and Hinode XRT.For the forthcoming 2017 eclipse, we acknowledge grants to JMP and Williams College from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation and from the Committee for Research and Exploration of the National Geographic Society.

  7. Deterministically Driven Avalanche Models of Solar Flares

    Science.gov (United States)

    Strugarek, Antoine; Charbonneau, Paul; Joseph, Richard; Pirot, Dorian

    2014-08-01

    We develop and discuss the properties of a new class of lattice-based avalanche models of solar flares. These models are readily amenable to a relatively unambiguous physical interpretation in terms of slow twisting of a coronal loop. They share similarities with other avalanche models, such as the classical stick-slip self-organized critical model of earthquakes, in that they are driven globally by a fully deterministic energy-loading process. The model design leads to a systematic deficit of small-scale avalanches. In some portions of model space, mid-size and large avalanching behavior is scale-free, being characterized by event size distributions that have the form of power-laws with index values, which, in some parameter regimes, compare favorably to those inferred from solar EUV and X-ray flare data. For models using conservative or near-conservative redistribution rules, a population of large, quasiperiodic avalanches can also appear. Although without direct counterparts in the observational global statistics of flare energy release, this latter behavior may be relevant to recurrent flaring in individual coronal loops. This class of models could provide a basis for the prediction of large solar flares.

  8. Modeling light trapping in nanostructured solar cells.

    Science.gov (United States)

    Ferry, Vivian E; Polman, Albert; Atwater, Harry A

    2011-12-27

    The integration of nanophotonic and plasmonic structures with solar cells offers the ability to control and confine light in nanoscale dimensions. These nanostructures can be used to couple incident sunlight into both localized and guided modes, enhancing absorption while reducing the quantity of material. Here we use electromagnetic modeling to study the resonances in a solar cell containing both plasmonic metal back contacts and nanostructured semiconductor top contacts, identify the local and guided modes contributing to enhanced absorption, and optimize the design. We then study the role of the different interfaces and show that Al is a viable plasmonic back contact material.

  9. Helioseismology challenges models of solar convection

    CERN Document Server

    Gizon, Laurent; 10.1073/pnas.1208875109

    2012-01-01

    Convection is the mechanism by which energy is transported through the outermost 30% of the Sun. Solar turbulent convection is notoriously difficult to model across the entire convection zone where the density spans many orders of magnitude. In this issue of PNAS, Hanasoge et al. (2012) employ recent helioseismic observations to derive stringent empirical constraints on the amplitude of large-scale convective velocities in the solar interior. They report an upper limit that is far smaller than predicted by a popular hydrodynamic numerical simulation.

  10. Solar Advisor Model User Guide for Version 2.0

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, P.; Blair, N.; Mehos, M.; Christensen, C.; Janzou, S.; Cameron, C.

    2008-08-01

    The Solar Advisor Model (SAM) provides a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, from photovoltaic systems for residential and commercial markets to concentrating solar power and large photovoltaic systems for utility markets. This manual describes Version 2.0 of the software, which can model photovoltaic and concentrating solar power technologies for electric applications for several markets. The current version of the Solar Advisor Model does not model solar heating and lighting technologies.

  11. Evidence of gravity waves into the atmosphere during the March 2006 total solar eclipse

    Directory of Open Access Journals (Sweden)

    C. S. Zerefos

    2007-05-01

    Full Text Available This study aims at testing the hypothesis according to which the movement of the moon's shadow sweeping the ozone layer at supersonic speed during a solar eclipse creates gravity waves in the atmosphere. An experiment was conducted to study fluctuations of the ozone layer, the Ionosonde Total Electron Content (ITEC and the peak electron density height (hmF2 in the ionosphere, as well as at a number of other parameters before, during and after the total solar eclipse. We found the existence of dominant oscillations with periods ranging between 30–40 min in most of the parameters. Cross-spectrum analyses between total ozone and various atmospheric parameters resulted to statistically significant square coherences between the observed oscillations, while the respective phase spectra show that the perturbation originates in the stratosphere and reaches the various layers at speeds around 20 km min−1. Additional evidence supporting these findings was provided by the amplitude of the oscillations in the ionospheric electron density, which increased upwards from 160 to 220 km height.

  12. Evidence of gravity waves into the atmosphere during the March 2006 total solar eclipse

    Directory of Open Access Journals (Sweden)

    C. S. Zerefos

    2007-09-01

    Full Text Available This study aims at providing experimental evidence, to support the hypothesis according to which the movement of the moon's shadow sweeping the ozone layer at supersonic speed, during a solar eclipse, creates gravity waves in the atmosphere. An experiment was conducted to study eclipse induced thermal fluctuations in the ozone layer (via measurements of total ozone column, ozone photolysis rates and UV irradiance, the ionosphere (Ionosonde Total Electron Content – ITEC, peak electron density height – hmF2, and the troposphere (temperature, relative humidity, before, during and after the total solar eclipse of 29 March 2006. We found the existence of eclipse induced dominant oscillations in the parameters related to the ozone layer and the ionosphere, with periods ranging between 30–40 min. Cross-spectrum analyses resulted to statistically significant square coherences between the observed oscillations, strengthening thermal stratospheric ozone forcing as the main mechanism for GWs. Additional support for a source below the ionosphere was provided by the amplitude of the oscillations in the ionospheric electron density, which increased upwards from 160 to 220 km height. Even though similar oscillations were shown in surface temperature and relative humidity data, no clear evidence for tropospheric influence could be derived from this study, due to the modest amplitude of these waves and the manifold rationale inside the boundary layer.

  13. Development of three-dimensional magnetohydrodynamic model for solar corona and solar wind simulation

    Science.gov (United States)

    Yuan, Xingqiu; Trichtchenko, Larisa; Boteler, David

    Propagation of coronal mass ejections from solar surface to the Earth magnetosphere is strongly influenced by the conditions in solar corona and ambient solar wind. Thus, reliable simulation of the background solar wind is the primary task toward the development of numerical model for the transient events. In this paper we introduce a new numerical model which has been specifically designed for numerical study of the solar corona and ambient solar wind. This model is based on our recently developed three-dimensional Spherical Coordinate Adaptive Magneto-Hydro-Dynamic (MHD) code (SCA-MHD-3D) [Yuan et al., 2009]. Modifications has been done to include the observed magnetic field at the photosphere as inner boundary conditions. The energy source term together with reduced plasma gamma are used in the nonlinear MHD equations in order to simulate the solar wind acceleration from subsonic speed at solar surface to supersonic speed at the inter-heliosphere region, and the absorbing boundary conditions are used at the solar surface. This model has been applied to simulate the background solar wind condition for several different solar rotations, and comparison between the observation and model output have shown that it reproduces many features of solar wind, including open and closed magnetic fields, fast and slow solar wind speed, sector boundaries, etc.

  14. Determination of Total Ozone over Mauna Loa Using Very High Resolution Infrared Solar Spectra

    Science.gov (United States)

    David, Shelle J.; Beaton, Sheryl A.; Anderberg, Mary H.; Murcray, Frank J.

    1993-01-01

    A very high resolution infrared Fourier transform spectrometer has been used to record solar spectra at the Mauna Loa Observatory in Hawaii. Spectra are normally taken one day a week at sunrise. These spectra have been analyzed for ozone and N2O total columns, and the ozone column compared with the value reported by tile Mauna Loa Dobson spectrophotometer. Aside from the FTIR reporting about 5% lower values than the Dobson (which may be due to a systematic difference in the treatment of tropospheric ozone), the FTIR and Dobson agree to within 2.7% (RMS) during this period.

  15. Prominence measurement of total solar eclipse: March 9th 2016, Ternate, Indonesia

    Science.gov (United States)

    Naufal, Luthfi; Abdan Malikul Mulki, Fargiza; Fatima, Siti; Widyanita; Zahirah, Saffanah; Dimas Satrya, Christoforus; Herdiwijaya, Dhani

    2016-11-01

    Prominence is a hot gas that consists of electrically charged particles, which is propelled outward Solar surface. It can happen when the activity of sunspot rising up. Ground- based observation of prominence is rather difficult due to the brightness of the Sun, which it needs appropriate method. During total solar eclipse (TSE), prominence is easier to observe. In Ternate, Maluku islands (0°4632.0"N 127°2305.7"E), we observed solar prominence in visual and infrared spectra performed by using regular-DSLR camera for visual wavelength and modified-DSLR (IR-cut filter removal) for infrared wavelength, respectively. Next, we calculated the length of prominence from TSE images, and found that the real minimum length of prominence in red is 1.05 times longer than green and blue ones. And, the real maximum length of prominence is 1.08 times longer than blue and 1.04 times longer than green. The intensity of red is brighter 1.37 times to green and 1.23 times to blue. The causes of the results due to the different temperatures of the prominences and the radiation from H-alpha emission. We succeeded to observe directly the prominence with simple cameras and measured its length and brightness.

  16. An update of Leighton's solar dynamo model

    CERN Document Server

    Cameron, R H

    2016-01-01

    In 1969 Leighton developed a quasi-1D mathematical model of the solar dynamo, building upon the phenomenological scenario of Babcock(1961). Here we present a modification and extension of Leighton's model. Using the axisymmetric component of the magnetic field, we consider the radial field component at the solar surface and the radially integrated toroidal magnetic flux in the convection zone, both as functions of latitude. No assumptions are made with regard to the radial location of the toroidal flux. The model includes the effects of turbulent diffusion at the surface and in the convection zone, poleward meridional flow at the surface and an equatorward return flow affecting the toroidal flux, latitudinal differential rotation and the near-surface layer of radial rotational shear, downward convective pumping of magnetic flux in the shear layer, and flux emergence in the form of tilted bipolar magnetic regions. While the parameters relevant for the transport of the surface field are taken from observations,...

  17. Plans to Observe the 2017 Total Solar Eclipse from near the Path Edges

    Science.gov (United States)

    Waring Dunham, David; Nugent, Richard; Guhl, Konrad; Bode, Hans-Joachim

    2015-08-01

    The August 21st, 2017 solar eclipse provides a good opportunity, to time the totality contacts, other Baily’s bead phenomena, and observe other dynamic edge phenomena, from locations near the edges of the path of totality. A good network of roads and generally favorable weather prospects means that more observers will likely be able to deploy more equipment than during most previous eclipses. The value of contact and Baily’s bead timings of total solar eclipses, for determining solar diameter and intensity variations, was described in an earlier presentation in Focus Meeting 13. This presentation will concentrate on how observations of different types that have been used during past eclipses can be made by different observers, to obtain better information about the accuracy of the different types of observations for determining the mean solar diameter, and the systematic differences between them. A problem has been that the few observers who have attempted recording Baily’s beads from path edge locations have wanted to use the latest technology, to try to record the observations better, rather than try to make the observations in the same ways that were used for many past eclipses. Several observers trying different techniques at the same location, and doing that at several locations at different places along the path, is needed. Past techniques that we would like to compare include direct visual observation (but keeping eye safety in mind); visual observation of telescopically projected images; direct filtered video telescopic observations; and recording the flash spectrum. There are several towns that straddle the path edges. The International Occultation Timing Association would like to mobilize people in those towns to observe the eclipse from many places, to say whether or not the eclipse happened, and if it did, time it. A suitable cell phone app could be designed to report observations, including the observer’s location, as was attempted for an

  18. On the integration of wind and solar energy to provide a total energy supply in the USA

    Science.gov (United States)

    Archer, Cristina; Mills, David; Cheng, Weili; Sloggy, Matthew; Liebig, Edwin; Rhoades, Alan

    2010-05-01

    This study examines the feasibility of using renewable energy - mostly wind and solar radiation - as the primary source of energy in the USA, under the assumption that a nationwide electric transmission grid is in place. Previous studies have shown that solar or wind alone can power the present U.S. grid on average. Other studies have shown that solar output from California and Texas using energy storage is well correlated with the state energy load on an hour by hour basis throughout the year and with the U.S. national load on a monthly basis. This study explores scenarios for use of wind and solar energy together at the national scale on an hour by hour basis to determine if such a combination is a better match to national seasonal load scenarios than either of the two alone on an hour-by-hour basis. Actual hour by hour national load data from the year 2006 are used as a basis, with some scenarios incorporating vehicle sector electrification and building heating and cooling using electric heat pumps. Hourly wind speed data were calculated at the hub height of 80 m above the ground for the year 2006 at over 150 windy locations in the continental U.S. using an extrapolation technique based on 10-m wind speed measurements and vertical sounding profiles. Using a 1.5 MW wind turbine as benchmark, the hourly wind power production nationwide was determined at all suitable locations. Similarly, the hourly output from solar plants, with and without thermal storage, was calculated based on Ausra's model assuming that the solar production would occur in the Southwest, the area with the greatest solar radiation density in the U.S. Hourly electricity demand for the year 2006 was obtained nationwide from a variety of sources, including the Federal Energy Regulation Commission. Hourly residential heating and cooking, industrial heat processing, and future electrified transportation loads were calculated from monthly and yearly energy consumption data from the Energy Information

  19. Broadband Spectroscopy of the Corona during the Total Solar Eclipse of March 29, 2006

    Science.gov (United States)

    Jaeggli, Sarah A.; Habbal, S. R.; Kuhn, J. R.; Nayfeh, M. H.

    2006-12-01

    We present coronal observations from the total solar eclipse of 29 March 2006 taken near Waw al Namus, Libya. During the 4 minutes and 6 seconds of totality, observations were made with a tracking collecting mirror and fiber-fed spectrograph. The spectrograph used is a high quantum efficiency commercial Ocean Optics QE65000 Spectrometer with a wavelength range of 350 to 1100 nm, and spectral resolution of about 0.75 nm. High quantum efficiency allowed for many short exposures of the inner (100 msec) and outer (10,000 msec) corona during the eclipse. Important spectral features, and the difference in color between the inner and outer corona are identified. Atmospheric contributions are discussed. Likely candidates for the nature of dust grains contributing to the F-corona measurements are also presented. These are compared with laboratory spectra of silicon nanoparticles.

  20. Coronal Mass Ejections Observed at the Total Solar Eclipse on 13 November 2012

    CERN Document Server

    Hanaoka, Yoichiro; Ohgoe, Osamu; Sakai, Yoshiaki; Shiota, Kazuo

    2013-01-01

    We carried out white-light observations of the total solar eclipse on 13 November 2012 at two sites, where the totality occurred 35 minutes apart. We caught an ongoing coronal mass ejection (CME) and a pre-CME loop structure just before the eruption in the height range between 1-2 R_sun. The source region of CMEs was revealed to be in this height range, where the material and the magnetic field of CMEs were located before the eruption. This height range includes the gap between the extreme ultraviolet observations of the low corona and the spaceborne white-light observations of the high corona, but the eclipse observation shows that this height range is essentially important to study the CME initiation. The eclipse observation is basically just a snapshot of CMEs, but it indicates that future continuous observations of CMEs within this height range are promising.

  1. solar magnetic fiber and space solar telescope in engineering model

    Science.gov (United States)

    Ai, G.

    The solar magnetic fiber and the magnetic element are the most important factor in the solar activity and solar atmosphere. Because the space resolution of measurement of solar magnetic field is much lower than that of the size of the nature solar magnetic fiber and element from the earth atmospheric turbulence. The estimate of the magnetic element nature from various indirect researches shows great difference with several orders. The research results about magnetic elements have been reviewed in the paper.Because the size of the magnetic element has been estimated for 0.1T-0.2T, the space solar magnetic field telescope with big diameter is the most basic choice. For the exploration of solar magnetic fiber and element, a Space Solar Telescope is under development in the phase C and D, there are five payloads which are: 1) MOT, 1 diameter telescope with 8 channels real time 2-D spectrograph and 8 sets CCD with 2K`2K; 2) EUV, 4 tubes of soft X-ray Telescope with 0.252 space resolution; 3) WBS, the wide Band Spectrometer with 256 channel from soft X-ray to Gamma-ray. 4) HAT, Ha and white light telescope; 5) SIRA, Solar and interplanetary Radio Spectrometer, with 100 KHZ-60 MHZ. The assembly and test will be introduced.

  2. The BAYSOFI Campaign - Measurements carried out during the total solar eclipse of August 11, 1999

    Directory of Open Access Journals (Sweden)

    Peter Fabian

    2001-05-01

    Full Text Available The total solar eclipse of August 11, 1999 provided a unique opportunity to observe the input of fast day-night and night-day transitions, under high solar elevation around noon, on the earth-atmosphere-biosphere system. Within the interdisciplinary field campaign BAYSOFI, measurements of radiation, boundary layer micrometeorology and photochemistry, photosynthesis and transpiration were carried out at Freising-Weihenstephan and several locations nearby focusing on short-term effects of the eclipse. Although the overall grosswetterlage on August 11 was not favourable for viewing the eclipse, with clouds covering most of central Europe, observational conditions at Weihenstephan were fair due to a large hole in the cloud layer which appeared just half hour before totality lasting for more than one hour. Thus significant effects of the eclipse on radiation, photolysis rates, OH, the temperature, wind, turbulence structure and stratification, ozone and CO2 fluxes, photosynthesis, transpiration and sap flow of trees could be observed which are reported and discussed in the following sequence of papers.

  3. Early Evaluation of the Corona at the 2016 March 9 Total Solar Eclipse

    Science.gov (United States)

    Pasachoff, Jay M.; Seaton, Daniel B.; Sterling, Alphonse C.

    2016-05-01

    We observed the corona on 2016 March 9 with a variety of assets on the ground and in space. The umbra of the total eclipse swept across Indonesia and into the Pacific, with totality at our Indonesian observation sites lasting 2 min 45 s at Ternate in the Spice Islands (Malukus) and 2 min 10 at Belitung. We compare our ground-based results with the coronal configurations observed with PROBA2/SWAP and Hinode XRT. One of our scientific goals is to follow the coronal configuration over the solar-activity cycle, with the sunspot number now half its maximum of either its 2012 or 2014 peak. We are evaluating temporal changes by comparing eclipse observations made at several ground-based sites along the path, with the longest span being 75 min from Belitung to the Woleia atoll in mid-Pacific, 1:25 UTC to 2:40 UTC; we are evaluating whether the airborne observations made at 3:35 UTC on March 8 (across the International Dateline) are of suitable quality to provide further comparison at high spatial resolution. We also compare our images with the near-simultaneous coronal observations made with SOHO/LASCO, SDO/AIA, STEREO-A/SECCHI, and the Mauna Loa Solar Observatory's K-cor coronagraph. ACS received support for image analysis from the Hinode project.

  4. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    Science.gov (United States)

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters.

  5. Thermodynamics of the Solar Corona and Evolution of the Solar Magnetic Field as Inferred from the Total Solar Eclipse Observations of 11 July 2010

    Science.gov (United States)

    Habbal, Shadia Rifai; Druckmueller, Miloslav; Morgan, Huw; Ding, Adalbert; Johnson, Judd; Druckmuellerova, Hana; Daw, Adrian; Arndt, Martina B.; Dietzel, Martin; Saken, Jon

    2011-01-01

    We report on multi-wavelength observations of the corona taken simultaneously in broadband white light, and in seven spectral lines, H-alpha 656.3 nm, Fe IX 435.9 nm, Fe X 637.4 nm, Fe XI 789.2 nm, Fe XIII 1074.7 nm, Fe XIV 530.3 nm and Ni XV 670.2 nm. The observations were made during the total solar eclipse of 11 July 2010 from the atoll of Tatakoto in French Polynesia. Simultaneous imaging with narrow bandpass filters in each of these spectral lines and in their corresponding underlying continua maximized the observing time during less than ideal observing conditions and yielded outstanding quality data. The application of two complementary image processing techniques revealed the finest details of coronal structures at 1" resolution in white light, and 6.5" in each of the spectral lines. This comprehensive wavelength coverage confirmed earlier eclipse findings that the solar corona has a clear two-temperature structure: The open field lines, expanding outwards from the solar surface, are characterized by electron temperatures near 1 X 10(exp 6) K, while the hottest plasma around 2X 10(exp 6) K resides in loop-like structures forming the bulges of streamers. The first images of the corona in the forbidden lines of Fe IX and Ni XV, showed that there was very little coronal plasma at temperatures below 5 X 10(exp 5) K and above 2.5X 10(exp 6) K. The data also enabled temperature differentiations as low as 0:2 X 10(exp 6) K in different density structures. These observations showed how the passage of CMEs through the corona, prior to totality, produced large scale ripples and very sharp streaks, which could be identified with distinct temperatures for the first time. The ripples were most prominent in emission from spectral lines associated with temperatures around 10(exp 6) K. The most prominent streak was associated with a conical-shaped void in the emission from the coolest line of Fe IX and from the hottest line of Ni XV. A prominence, which erupted prior to

  6. Micrometeorological measurements during the total solar eclipse of August 11, 1999

    Directory of Open Access Journals (Sweden)

    Thomas Foken

    2001-05-01

    Full Text Available Micrometeorological measurements of radiation, atmospheric and soil parameters, and turbulent energy and momentum fluxes, ozone and carbon dioxide fluxes have been conducted over a maize field at Freising-Weihenstephan in Southern Germany during the total solar eclipse on August 11, 1999. For the period 30 minutes before and after the totality the weather conditions at the location where the micrometeorological measurements were made was satisfactory. Several connections between the irradiation and other meteorological parameters over a maize field have been found. The time response between irradiation and the long-wave upward radiation was only a few minutes, whereas almost all parameters caused by the turbulent transport had a time shift of up to 30 minutes. A period of nearly 30 minutes with reduced turbulence regime after the totality was found. Using a wavelet transformation for the time series, a change of time scales from longer to shorter ones was observed before the totality, and after the turbulence increased in the short time scales. The investigation of the residuum of the closure of the energy balance showed that with a time shift for the latent heat flux (unlike the net radiation after the totality, a better energy budget closure was obtained.

  7. Introducing a novel method to estimate the total heat transfer coefficient inside irregular-shape cavities utilizing thermoelectric modules; Special application in solar engineering

    DEFF Research Database (Denmark)

    Asadi, Amin; Rahbar, Nader; Rezaniakolaei, Alireza

    2017-01-01

    The main objective of the present study is to introduce a novel method to measure the total heat transfer coefficient inside irregular-shape cavities, used in solar applications, utilizing thermoelectric modules. Applying mathematical and thermodynamics modeling, the governing equations related...... transfer coefficient inside irregular-shape cavities. The average deviation between experimental data and the output of the proposed equation is approximately 9 %, which shows the good ability of the equation in estimating the total heat transfer coefficient....

  8. Helioseismic Data Assimilation in Solar Dynamo Models

    CERN Document Server

    Muñoz-Jaramillo, Andrés; Martens, Petrus C H

    2008-01-01

    An essential ingredient in kinematic dynamo models is the velocity field within the solar convection zone. In particular, the differential rotation is now well constrained by helioseismic observations. Helioseismology also gives us information about the depth-dependence of the meridional circulation in the near-surface layers. The typical velocity inputs used in solar dynamo models, however, continue to be an analytic fit to the observed differential rotation and a theoretically constructed meridional flow profile that matches only the peak flow speed at the surface. Here we take the first steps towards realistic helioseismic data assimilation, by presenting methodologies for constructing differential rotation and meridional circulation profiles that more closely conform to the observational constraints currently available. We also present simulations driven by the assimilated rotation and four plausible profiles for the internal meridional circulation -- all of which match the helioseismically inferred near-...

  9. Solar radiation practical modeling for renewable energy applications

    CERN Document Server

    Myers, Daryl Ronald

    2013-01-01

    Written by a leading scientist with over 35 years of experience working at the National Renewable Energy Laboratory (NREL), Solar Radiation: Practical Modeling for Renewable Energy Applications brings together the most widely used, easily implemented concepts and models for estimating broadband and spectral solar radiation data. The author addresses various technical and practical questions about the accuracy of solar radiation measurements and modeling. While the focus is on engineering models and results, the book does review the fundamentals of solar radiation modeling and solar radiation m

  10. Investigation the effect of total solar eclipse March 9, 2016 on tidal elevation study cases: Bangka and Belitung islands

    Science.gov (United States)

    Radjawane, I. M.; Simanjuntak, E. M.; Adziima, A. F.; Sofian, I.

    2016-11-01

    Tidal elevation is generating primary by the gravitational forces between earth with moon and solar. Since the sun plays an important role on generating the tidal sea level then the effect of total solar eclipse (TSE) March 9, 2016 on surface water level has been analysed from real time one-minute tide gauge station from Geospatial Information Agency. Two stations was selected to observe the impact of TSE i.e. in coastal of Bangka Island where totally path of TSE was detected and the other is in the coastal Belitung Island, located near to Bangka Island. We compare the observed sea level with the predicted sea level from 9 constituents using Tidal Model Driver (TMD). The result shows that during the TSE in Bangka Island, the observed tidal phase is shifted and observed sea level is higher compare with the prediction one. But in Belitung Island, there is no pattern change of tidal phase and with small increasing sea level compare with the prediction.

  11. Educational and Public Outreach Strategies in Anticipation of the 2017 U.S. Total Solar Eclipse

    Science.gov (United States)

    Fulco, C.

    2015-12-01

    Those who have experienced a total solar eclipse will travel to every corner of the Earth to observe one, such is its spectacular nature. So it is fortunate indeed to have this remarkable event come to the U.S. in less than two years, with its path of totality from Oregon to South Carolina within a day's drive for most of the nation's population. The date of the 21 August 2017 "Great American Eclipse" is rapidly approaching, and with focus on science literacy in U.S. schools greater than ever, educational and public outreach (EPO) must begin in earnest to maximize the scientific and educational benefits from this rare event. As every location in the U.S. will observe at least a partial eclipse, having EPO strategies in place ensures that the greatest number of students and other observers throughout the country will: a) be aware of and prepared for this event, b) observe (and record) it safely and knowledgeably, and c) gain an increased awareness of the natural world. The need for teachers to promote scientific literacy through curriculum is critical for this event. Despite an increased presence of technology in the classroom, more rigorous educational learning standards and virtually instantaneous access to information, data show that science illiteracy in U.S. schools and in the general population is still widespread. In addition, much fear, ignorance and confusion continue to surround eclipses. Many school districts plan to keep students indoors during the eclipse, while the media can be expected to instruct the public to do the same, thus depriving would-be observers of an unforgettable and most likely a once-in-a-lifetime experience. It would be a tragedy on many levels if this eclipse were not viewed, recorded and remembered live and outdoors--not indoors watching on media--by as many persons as possible. Proper EPO strategies performed with ample lead time can ensure that the 2017 U.S. Total Solar Eclipse will be a success from coast-to-coast, and with it, a

  12. Development of a Greek solar map based on solar model estimations

    Science.gov (United States)

    Kambezidis, H. D.; Psiloglou, B. E.; Kavadias, K. A.; Paliatsos, A. G.; Bartzokas, A.

    2016-05-01

    The realization of Renewable Energy Sources (RES) for power generation as the only environmentally friendly solution, moved solar systems to the forefront of the energy market in the last decade. The capacity of the solar power doubles almost every two years in many European countries, including Greece. This rise has brought the need for reliable predictions of meteorological data that can easily be utilized for proper RES-site allocation. The absence of solar measurements has, therefore, raised the demand for deploying a suitable model in order to create a solar map. The generation of a solar map for Greece, could provide solid foundations on the prediction of the energy production of a solar power plant that is installed in the area, by providing an estimation of the solar energy acquired at each longitude and latitude of the map. In the present work, the well-known Meteorological Radiation Model (MRM), a broadband solar radiation model, is engaged. This model utilizes common meteorological data, such as air temperature, relative humidity, barometric pressure and sunshine duration, in order to calculate solar radiation through MRM for areas where such data are not available. Hourly values of the above meteorological parameters are acquired from 39 meteorological stations, evenly dispersed around Greece; hourly values of solar radiation are calculated from MRM. Then, by using an integrated spatial interpolation method, a Greek solar energy map is generated, providing annual solar energy values all over Greece.

  13. UBVRI Observations And Analysis Of The Solar Type, Total Eclipsing Binary, TYC 3034-299-1

    Science.gov (United States)

    Faulkner, Danny R.; Blum, N.; Samec, R. G.; Jaso, A.; Smith, P. M.; White, J.; Van Hamme, W.

    2012-01-01

    TYC 3034-299-1 (CVn) is a magnetically active, solar type contact binary and a ROTSE variable. This system was observed as a part of our continuing student/professional collaborative study of interacting binaries. The current UBVRI light curves were taken with the Lowell 0.81-m reflector in Flagstaff on May 10 and May 11, 2010. Four times of minimum light were determined from our observations. They include (with standard errors): HJD I = 2455326.72754±0.00024, 2455327.713303±0.00025, HJD II = 2455326.92427±0.00068, 2455327.91256±0.00060. We also obtained the following timings of minimum light from parabolic fits to the data of Blattler (IBVS number 5699, 2006): HJD I = 2453382.6915, 2453445.4980, 2453502.3800, 2453515.4154, 2453517.3907, HJD II = 2453463.4719, 2453515.607. From these and Nelson's (IBVS numbers 5875 and 5929, 2009) observations, an improved ephemeris was calculated from all the available eclipse timings: J.D. Hel Min I = 2455326.9244±0.0005 + 0.39500870 ± 0.00000016 d*E. Our light curve amplitudes are deep for a contact binary, ranging from 0.85 magnitude in U to 0.66 in I. Time of totality of 7 minutes was detected in the secondary eclipse indicating that this system is a W-type W UMa system (less massive star is hotter). The O'Connell effect ranges from 67 mmag to 36 mmag in U to I, respectively, revealing substantial magnetic activity. A 5-color simultaneous light curve solution was calculated using the Wilson Code. Our model reveals a dark spot region at longitude 58°. The 18% fill-out and the virtually identical temperatures of the two stars show that the system has nearly reached thermal contact. We performed a q-search over the interval from q = 0.3 to 0.8. The mass ratio is 0.46. We wish to thank Lowell Observatory for their allocation of observing time and the American Astronomical Society and the Arizona Space Grant for travel support for this observing run.

  14. Deterministically Driven Avalanche Models of Solar Flares

    CERN Document Server

    Strugarek, Antoine; Joseph, Richard; Pirot, Dorian

    2014-01-01

    We develop and discuss the properties of a new class of lattice-based avalanche models of solar flares. These models are readily amenable to a relatively unambiguous physical interpretation in terms of slow twisting of a coronal loop. They share similarities with other avalanche models, such as the classical stick--slip self-organized critical model of earthquakes, in that they are driven globally by a fully deterministic energy loading process. The model design leads to a systematic deficit of small scale avalanches. In some portions of model space, mid-size and large avalanching behavior is scale-free, being characterized by event size distributions that have the form of power-laws with index values, which, in some parameter regimes, compare favorably to those inferred from solar EUV and X-ray flare data. For models using conservative or near-conservative redistribution rules, a population of large, quasiperiodic avalanches can also appear. Although without direct counterparts in the observational global st...

  15. Attenuation of global ultraviolet and visible irradiance over Greece during the total solar eclipse of 29 March 2006

    Directory of Open Access Journals (Sweden)

    A. Kazantzidis

    2007-09-01

    Full Text Available The variability of ultraviolet and photosynthetically active radiation during the total solar eclipse of 29 March 2006 was examined in this study. The measurements from NILU-UV multichannel actinometers at 7 stations of the Greek UV Network were used, where the maximum eclipse percentage ranged from 73.1% to 94.8%. In addition, an extra instrument was established at a remote Greek island, Kastelorizo, which was within the Moon's umbral shadow. The measured changes in UV and visible irradiance were compared with 1-D model calculations (accounting for the limb darkening effect and differences up 30% were observed for the lower UV wavelengths at high eclipse percentages. The spectral ratios between wavelengths was generally reproduced by the 1-D model, expect for 305 nm, where the irradiance at eclipse percentages of more than 85% decreased with slower rates than for longer wavelengths. As a result, the total ozone, derived from the 305/320 nm ratio, apparently decreased significantly for high eclipse percentages. Comparison results with 3-D model calculations approaching and during totality revealed an agreement with measurements in the UV-A region.

  16. An Independent Measurement of the Total Active 8B Solar Neutrino Flux Using an Array of 3He Proportional Counters at the Sudbury Neutrino Observatory

    CERN Document Server

    Aharmim, B; Amsbaugh, J F; Anthony, A E; Banar, J; Barros, N; Beier, E W; Bellerive, A; Beltran, B; Bergevin, M; Biller, S D; Boudjemline, K; Boulay, M G; Bowles, T J; Browne, M C; Bullard, T V; Burritt, T H; Cai, B; Chan, Y D; Chauhan, D; Chen, M; Cleveland, B T; Cox-Mobrand, G A; Currat, C A; Dai, X; Deng, H; Detwiler, J; Di Marco, M; Doe, P J; Doucas, G; Drouin, P L; Duba, C A; Duncan, F A; Dunford, M; Earle, E D; Elliott, S R; Evans, H C; Ewan, G T; Farine, J; Fergani, H; Fleurot, F; Ford, R J; Formaggio, J A; Fowler, M M; Gagnon, N; Germani, J V; Goldschmidt, A; Goon, J T M; Graham, K; Guillian, E; Habib, S; Hahn, R L; Hallin, A L; Hallman, E D; Hamian, A A; Harper, G C; Harvey, P J; Hazama, R; Heeger, K M; Heintzelman, W J; Heise, J; Helmer, R L; Henning, R; Hime, A; Howard, C; Howe, M A; Huang, M; Jagam, P; Jamieson, B; Jelley, N A; Keeter, K J; Klein, J R; Kormos, L L; Kos, M; Krüger, A; Kraus, C; Krauss, C B; Kutter, T; Kyba, C C M; Lange, R; Law, J; Lawson, I T; Lesko, K T; Leslie, J R; Loach, J C; MacLellan, R; Majerus, S; Mak, H B; Maneira, J; Martin, R; McBryde, K; McCauley, N; McDonald, A B; McGee, S; Miin, C; Miller, G G; Miller, M L; Monreal, B; Monroe, J; Morissette, B; Myers, A; Nickel, B G; Noble, A J; Oblath, N S; O'Keeffe, H M; Ollerhead, R W; Orebi Gann, G D; Oser, S M; Ott, R A; Peeters, S J M; Poon, A W P; Prior, G; Reitzner, S D; Rielage, K; Robertson, B C; Robertson, R G H; Rollin, E; Schwendener, M H; Secrest, J A; Seibert, S R; Simard, O; Simpson, J J; Sinclair, L; Skensved, P; Smith, M W E; Steiger, T D; Stonehill, L C; Tesic, G; Thornewell, P M; Tolich, N; Tsui, T; Tunnell, C D; Van Wechel, T; Van Berg, R; Van Devender, B A; Virtue, C J; Walker, T J; Wall, B L; Waller, D; Wan Chan Tseung, H; Wendland, J; West, N; Wilhelmy, J B; Wilkerson, J F; Wilson, J R; Wouters, J M; Wright, A; Yeh, M; Zhang, F; Zuber, K

    2008-01-01

    The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54(+0.33/-0.31 stat, +0.36/-0.34 syst) x 10^6 cm^-2 s^-1, in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Delta m^2 = 7.94(+0.42/-0.26) x 10^-5 eV^2 and theta = 33.8(+1.4/-1.3) degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.

  17. Independent Measurement of the Total Active B8 Solar Neutrino Flux Using an Array of He3 Proportional Counters at the Sudbury Neutrino Observatory

    Science.gov (United States)

    Aharmim, B.; Ahmed, S. N.; Amsbaugh, J. F.; Anthony, A. E.; Banar, J.; Barros, N.; Beier, E. W.; Bellerive, A.; Beltran, B.; Bergevin, M.; Biller, S. D.; Boudjemline, K.; Boulay, M. G.; Bowles, T. J.; Browne, M. C.; Bullard, T. V.; Burritt, T. H.; Cai, B.; Chan, Y. D.; Chauhan, D.; Chen, M.; Cleveland, B. T.; Cox-Mobrand, G. A.; Currat, C. A.; Dai, X.; Deng, H.; Detwiler, J.; Dimarco, M.; Doe, P. J.; Doucas, G.; Drouin, P.-L.; Duba, C. A.; Duncan, F. A.; Dunford, M.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Fleurot, F.; Ford, R. J.; Formaggio, J. A.; Fowler, M. M.; Gagnon, N.; Germani, J. V.; Goldschmidt, A.; Goon, J. T. M.; Graham, K.; Guillian, E.; Habib, S.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamian, A. A.; Harper, G. C.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Henning, R.; Hime, A.; Howard, C.; Howe, M. A.; Huang, M.; Jagam, P.; Jamieson, B.; Jelley, N. A.; Keeter, K. J.; Klein, J. R.; Kormos, L. L.; Kos, M.; Krüger, A.; Kraus, C.; Krauss, C. B.; Kutter, T.; Kyba, C. C. M.; Lange, R.; Law, J.; Lawson, I. T.; Lesko, K. T.; Leslie, J. R.; Loach, J. C.; MacLellan, R.; Majerus, S.; Mak, H. B.; Maneira, J.; Martin, R.; McBryde, K.; McCauley, N.; McDonald, A. B.; McGee, S.; Mifflin, C.; Miller, G. G.; Miller, M. L.; Monreal, B.; Monroe, J.; Morissette, B.; Myers, A.; Nickel, B. G.; Noble, A. J.; Oblath, N. S.; O'Keeffe, H. M.; Ollerhead, R. W.; Gann, G. D. Orebi; Oser, S. M.; Ott, R. A.; Peeters, S. J. M.; Poon, A. W. P.; Prior, G.; Reitzner, S. D.; Rielage, K.; Robertson, B. C.; Robertson, R. G. H.; Rollin, E.; Schwendener, M. H.; Secrest, J. A.; Seibert, S. R.; Simard, O.; Simpson, J. J.; Sinclair, L.; Skensved, P.; Smith, M. W. E.; Steiger, T. D.; Stonehill, L. C.; Tešić, G.; Thornewell, P. M.; Tolich, N.; Tsui, T.; Tunnell, C. D.; van Wechel, T.; van Berg, R.; Vandevender, B. A.; Virtue, C. J.; Walker, T. J.; Wall, B. L.; Waller, D.; Tseung, H. Wan Chan; Wendland, J.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J. R.; Wouters, J. M.; Wright, A.; Yeh, M.; Zhang, F.; Zuber, K.

    2008-09-01

    The Sudbury Neutrino Observatory (SNO) used an array of He3 proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (νx) B8 solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54-0.31+0.33(stat)-0.34+0.36(syst)×106cm-2s-1, in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Δm2=7.59-0.21+0.19×10-5eV2 and θ=34.4-1.2+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO’s previous results.

  18. Independent measurement of the total active 8B solar neutrino flux using an array of 3He proportional counters at the Sudbury Neutrino Observatory.

    Science.gov (United States)

    Aharmim, B; Ahmed, S N; Amsbaugh, J F; Anthony, A E; Banar, J; Barros, N; Beier, E W; Bellerive, A; Beltran, B; Bergevin, M; Biller, S D; Boudjemline, K; Boulay, M G; Bowles, T J; Browne, M C; Bullard, T V; Burritt, T H; Cai, B; Chan, Y D; Chauhan, D; Chen, M; Cleveland, B T; Cox-Mobrand, G A; Currat, C A; Dai, X; Deng, H; Detwiler, J; DiMarco, M; Doe, P J; Doucas, G; Drouin, P-L; Duba, C A; Duncan, F A; Dunford, M; Earle, E D; Elliott, S R; Evans, H C; Ewan, G T; Farine, J; Fergani, H; Fleurot, F; Ford, R J; Formaggio, J A; Fowler, M M; Gagnon, N; Germani, J V; Goldschmidt, A; Goon, J T M; Graham, K; Guillian, E; Habib, S; Hahn, R L; Hallin, A L; Hallman, E D; Hamian, A A; Harper, G C; Harvey, P J; Hazama, R; Heeger, K M; Heintzelman, W J; Heise, J; Helmer, R L; Henning, R; Hime, A; Howard, C; Howe, M A; Huang, M; Jagam, P; Jamieson, B; Jelley, N A; Keeter, K J; Klein, J R; Kormos, L L; Kos, M; Krüger, A; Kraus, C; Krauss, C B; Kutter, T; Kyba, C C M; Lange, R; Law, J; Lawson, I T; Lesko, K T; Leslie, J R; Loach, J C; MacLellan, R; Majerus, S; Mak, H B; Maneira, J; Martin, R; McBryde, K; McCauley, N; McDonald, A B; McGee, S; Mifflin, C; Miller, G G; Miller, M L; Monreal, B; Monroe, J; Morissette, B; Myers, A; Nickel, B G; Noble, A J; Oblath, N S; O'Keeffe, H M; Ollerhead, R W; Gann, G D Orebi; Oser, S M; Ott, R A; Peeters, S J M; Poon, A W P; Prior, G; Reitzner, S D; Rielage, K; Robertson, B C; Robertson, R G H; Rollin, E; Schwendener, M H; Secrest, J A; Seibert, S R; Simard, O; Simpson, J J; Sinclair, L; Skensved, P; Smith, M W E; Steiger, T D; Stonehill, L C; Tesić, G; Thornewell, P M; Tolich, N; Tsui, T; Tunnell, C D; Van Wechel, T; Van Berg, R; VanDevender, B A; Virtue, C J; Walker, T J; Wall, B L; Waller, D; Tseung, H Wan Chan; Wendland, J; West, N; Wilhelmy, J B; Wilkerson, J F; Wilson, J R; Wouters, J M; Wright, A; Yeh, M; Zhang, F; Zuber, K

    2008-09-12

    The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54_-0.31;+0.33(stat)-0.34+0.36(syst)x10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Deltam2=7.59_-0.21;+0.19x10(-5) eV2 and theta=34.4_-1.2;+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.

  19. A Model for the Sources of the Slow Solar Wind

    Science.gov (United States)

    Antiochos, Spiro K.; Mikic, Z.; Lionello, R.; Titov, V.; Linker, J.

    2010-05-01

    Models for the origin of the slow solar wind must account for two seemingly contradictory observations: The slow wind has the composition of the closed-field corona, implying that it originates at the open-closed field boundary layer, but it also has large angular width, up to 40 degrees. We propose a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We calculate with high numerical resolution, the quasi-steady solar wind and magnetic field for a Carrington rotation centered about the August 1, 2008 total solar eclipse. Our numerical results demonstrate that, at least for this time period, a web of separatrices (S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow wind. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere, and propose further tests of the model. This work was supported, in part, by the NASA HTP, TR&T and SR&T programs.

  20. Modeling Anomalous Hysteresis in Perovskite Solar Cells.

    Science.gov (United States)

    van Reenen, Stephan; Kemerink, Martijn; Snaith, Henry J

    2015-10-01

    Organic-inorganic lead halide perovskites are distinct from most other semiconductors because they exhibit characteristics of both electronic and ionic motion. Accurate understanding of the optoelectronic impact of such properties is important to fully optimize devices and be aware of any limitations of perovskite solar cells and broader optoelectronic devices. Here we use a numerical drift-diffusion model to describe device operation of perovskite solar cells. To achieve hysteresis in the modeled current-voltage characteristics, we must include both ion migration and electronic charge traps, serving as recombination centers. Trapped electronic charges recombine with oppositely charged free electronic carriers, of which the density depends on the bias-dependent ion distribution in the perovskite. Our results therefore show that reduction of either the density of mobile ionic species or carrier trapping at the perovskite interface will remove the adverse hysteresis in perovskite solar cells. This gives a clear target for ongoing research effort and unifies previously conflicting experimental observations and theories.

  1. Solar models with accretion. I. Application to the solar abundance problem

    CERN Document Server

    Serenelli, Aldo M; Pena-Garay, Carlos

    2011-01-01

    We generate new standard solar models using newly analyzed nuclear fusion cross sections and present results for helioseismic quantities and solar neutrino fluxes. We discuss the status of the solar abundance problem and investigate whether nonstandard solar models with accretion from the protoplanetary disk might alleviate the problem. We examine a broad range of possibilities, analyzing both metal-enriched and metal-depleted accretion models and exploring three scenarios for the timing of the accretion. Only partial solutions are found: one can bring either the depth of the convective zone or the surface helium abundance into agreement with helioseismic results, but not both simultaneously. In addition, detailed results for solar neutrino fluxes show that neutrinos are a competitive source of information about the solar core and can help constrain possible accretion histories of the Sun. Finally, we briefly discuss how measurements of solar neutrinos from the CN-cycle could shed light on the interaction bet...

  2. Model for computation of solar fraction in a single-slope solar still

    Energy Technology Data Exchange (ETDEWEB)

    Madhlopa, A.; Johnstone, C. [Energy Systems Research Unit, Department of Mechanical Engineering, University of Strathclyde, 75 Montrose Street, Glasgow G1 1XJ (United Kingdom)

    2009-06-15

    A new model that calculates the distribution of solar radiation inside a single-slope solar still has been proposed. In this model, the solar fraction on a vertical surface is divided into beam and diffuse parts and the optical view factors of surfaces inside the still are taken into account. To validate the model, outdoor tests of a conventional solar still were conducted under different weather conditions at the University of Strathclyde. The proposed model is compared with the previous one. It is found that the beam solar fraction is affected by both the geometry of the solar still and position of the sun in the sky. In contrast, the diffuse solar fraction is only dependent on the geometry of the solar distiller. The present model exhibited a lower root mean square error than that of the previous model. It appears that splitting the solar fraction into beam and diffuse parts improves the accuracy of modelling the performance of a single-slope solar still. (author)

  3. Solar Electric Bicycle Body Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    Zhikun Wang

    2013-10-01

    Full Text Available A new solar electric bicycle design and study were carried out on in this paper. Application of CAD technology to establish three-dimension geometric model, using the kinetic analysis on the frame and other parts for numerical simulation and static strength analysis for the vehicle model design, virtual assembly, complete frame dynamics analysis and vibration analysis, with considering other factors, first on the frame structure improvement, second on security of design calculation analysis and comparison, finally get the ideal body design.

  4. A Solar Model with g-Modes

    Science.gov (United States)

    Wolff, Charles L.; Niemann, Hasso (Technical Monitor)

    2002-01-01

    Good evidence is assembled showing that the Suit's core arid surface vary on time scales from a month to a decade arid that a number of scales are similar. The most plausible source for numerous long time scales and periodicities is long-lived global oscillations. This suggests g-modes (oscillations restored mainly by buoyancy) because they particularly affect the core and base of the convective envelope, which then indirectly modulates the surface. Also, standing g-modes have rotational properties that match many observed periodicities. But the standard solar model (SSM) has a static core and excites few if any g-modes. making new interior structures worth exploring. The model outlined here assumes two well mixed shells near 0.18 and 0.68 R, (13 = solar radius) where sound speed data shows sharp deviations from the SSM. Mixing is sustained by flows driven by the oscillations. The shells form a cavity that excludes g-modes from their main damping region below 0.1 R, assisting their net excitation and increasing their oscillation periods by at least a factor of two and probably much more. In terms of the solar luminosity L, the modes transport up through the cavity a power approx. 0.004 L as a lower limit and 0.11 L as all upper limit. The modes dissipate energy in the outer shell and cool the inner shell, asymmetrically in each case, and this stimulates occasional convective events whose response time is typically 0.8 years longer near the inner shell. Such events cool the core and reduce neutrino flux while heating the envelope and increasing solar activity. This gives a physical basis for a well mixed Sun with low neutrino flux and basis for the observed anticorrelation and lag of neutrino behind surface activity.

  5. Modeling the Effects of Solar Cell Attitude Distribution on Optical Cross Section for Solar Panel Simulations

    Science.gov (United States)

    Feirstine, K.; Bush, K.; Crosher, C.; Klein, M.; Bowers, D.; Wellems, D.; Duggin, M.; Vaughn, L.

    2012-09-01

    The Air Force Research Laboratory (AFRL) Time-domain Analysis Simulation for Advanced Tracking (TASAT) was used to explore the variation of Optical Cross Section (OCS) with glint angle for a solar panel with different solar cell attitude distribution statistics. Simulations were conducted using a 3D model of a solar panel with various solar cell tip and tilt distribution statistics. Modeling a solar panel as a single sheet of "solar cell" material is not appropriate for OCS glint studies. However, modeling each individual solar cell on the panel, the tips and tilts of which come from a distribution of specified statistics (distribution type, mean, and standard deviation), accurately captures the solar panel OCS with glint angle. The objective of the simulations was to vary the glint measurement angle about the maximum glint position of the solar panel and observe the variations in OCS with angle for a bi-static illumination condition. OCS was calculated relative to the simulated scattering of a Spectralon material in the glint orientation. Results show the importance of solar cell attitude distribution statistics in modeling the OCS observed for a solar panel.

  6. Computer Modelling and Simulation of Solar PV Array Characteristics

    Science.gov (United States)

    Gautam, Nalin Kumar

    2003-02-01

    The main objective of my PhD research work was to study the behaviour of inter-connected solar photovoltaic (PV) arrays. The approach involved the construction of mathematical models to investigate different types of research problems related to the energy yield, fault tolerance, efficiency and optimal sizing of inter-connected solar PV array systems. My research work can be divided into four different types of research problems: 1. Modeling of inter-connected solar PV array systems to investigate their electrical behavior, 2. Modeling of different inter-connected solar PV array networks to predict their expected operational lifetimes, 3. Modeling solar radiation estimation and its variability, and 4. Modeling of a coupled system to estimate the size of PV array and battery-bank in the stand-alone inter-connected solar PV system where the solar PV system depends on a system providing solar radiant energy. The successful application of mathematics to the above-m entioned problems entailed three phases: 1. The formulation of the problem in a mathematical form using numerical, optimization, probabilistic and statistical methods / techniques, 2. The translation of mathematical models using C++ to simulate them on a computer, and 3. The interpretation of the results to see how closely they correlated with the real data. Array is the most cost-intensive component of the solar PV system. Since the electrical performances as well as life properties of an array are highly sensitive to field conditions, different characteristics of the arrays, such as energy yield, operational lifetime, collector orientation, and optimal sizing were investigated in order to improve their efficiency, fault-tolerance and reliability. Three solar cell interconnection configurations in the array - series-parallel, total-cross-tied, and bridge-linked, were considered. The electrical characteristics of these configurations were investigated to find out one that is comparatively less susceptible to

  7. VLF signal perturbation due to the total solar eclipse of March 2015

    Science.gov (United States)

    Nait Amor, Samir; Bouderba, Yasmina

    2016-07-01

    On March 20 2015 a total Solar eclipse occurred and covered several regions in north America, Greenland, west of Europe and north Africa with different occultation rates. During this event, many VLF paths recorded at Algiers receiver were perturbed. In this contribution, we will present a qualitative analysis of two paths (GQD and DHO) which were disturbed differently since the occultation rate at the transmitter locations was different. In addition to the qualitative study, we determined the newly formed reference height and β values at different times during the eclipse transit. From these determined parameters the time profile of the electron density is then deduced. The results showed that the new reference height, β and the electron density are different from one transmitter analysis to other due to the occultation rate difference.

  8. Solar activity variability in the IRI at high latitudes: Comparisons with GPS total electron content

    Science.gov (United States)

    Themens, David R.; Jayachandran, P. T.

    2016-04-01

    Total electron content (TEC) measurements from 10 dual-frequency GPS receivers in the Canadian High Arctic Ionospheric Network (CHAIN) are used to evaluate the performance of International Reference Ionosphere (IRI)-2007 within the Canadian sector. Throughout the region, we see systematic underestimation of daytime TEC, particularly at solar maximum, where summer and equinox root-mean-square errors reach as high as 14 total electron content units, 1 TECU = 1016 el m-2 (TECU). It is also shown that the use of a monthly IG index, in place of the IRI's standard IG12 index, leads to an improvement in TEC specification by up to 3 TECU in the polar cap and up to 6 TECU in the subauroral region during periods of short-term, large amplitude changes in solar activity. On diurnal timescales, variability in TEC is found to be underestimated by the IRI, during equinox periods, by up to 40% at subauroral latitudes and up to 70% in the polar cap region. During the winter, diurnal variations are overestimated by up to 40% in the subauroral region and are underestimated within the polar cap by up to 80%. Using collocated ionosonde data, we find IRI bottomside TEC to be within 1 TECU of observation with errors largest during the equinoxes. For the topside we find good agreement during the winter but significant underestimation of topside TEC by the IRI during summer and equinox periods, exceeding 6 TECU at times. By ingesting measured NmF2 into the IRI, we show that the topside thickness parameterization is the source of the bulk of the observed TEC errors.

  9. First light measurements of the Total Solar Irradiance experiment CLARA on NORSAT-1

    Science.gov (United States)

    Schmutz, Werner

    2016-07-01

    NORSAT-1 is a Norwegian micro-satellite, which will be launched April 22, 2016. (In the future at the time of writing this abstract.) The satellite carries two scientific instruments and an AIS receiver for performing ship detection from space. One of the scientific instruments is a Compact Light-weight Absolute RAdiometer (CLARA) and the other is a Langmuir Probe instrument comprising four probes mounted on booms. The latter experiment will measure electron density and the platform's floating potential along the orbit. The University of Oslo provides the Langmuir probes. The radiometer experiment CLARA has been built by PMOD/WRC funded through the Swiss PRODEX program. It will measure Total Solar Irradiance with an instrument of novel design that is optimized for minimizing mass and size by still ensuring highest measuring accuracy and thermal stability. The radiometers of CLARA have been fully characterized as well as calibrated at the TRF facility. It is expected that the first light accuracy of the absolute measurement of Total Solar Irradiance will be better than pm0.3 W/m^{2, allowing to probe the current TSI composite for its absolute level. The presentation will give an overview of the CLARA instrument and its calibration. It is expected that at the time of the COSPAR conference the first light TSI value of CLARA/NORSAT-1 is ready for publication. Together with a previous absolute TSI measurements available for July 27, 2010 measured by PREMOS/PICARD the new absolute TSI measurement will be used to test the accuracy of long term TSI trend given by the relative TSI composite.

  10. Contribution to the modeling of solar spicules

    CERN Document Server

    Tavabi, E; Ajabshirizadeh, A

    2011-01-01

    Solar limb and disc spicule quasi- periodic motions have been reported for a long time, strongly suggesting that they are oscillating. In order to clear up the origin and possibly explain some solar limb and disc spicule quasi-periodic recurrences produced by overlapping effects, we present a simulation model assuming quasi- random positions of spicules. We also allow a set number of spicules with different physical properties (such as: height, lifetime and tilt angle as shown by an individual spicule) occurring randomly. Results of simulations made with three different spatial resolutions of the corresponding frames and also for different number density of spicules, are analyzed. The wavelet time/frequency method is used to obtain the exact period of spicule visibility. Results are compared with observations of the chromosphere from i/ the Transition Region and Coronal Explorer (TRACE) filtergrams taken at 1600 angstrom, ii/ the Solar Optical Telescope (SOT) of Hinode taken in the Ca II H-line and iii/ the S...

  11. Nonlinear Dynamic Model Explains The Solar Dynamic

    Science.gov (United States)

    Kuman, Maria

    Nonlinear mathematical model in torus representation describes the solar dynamic. Its graphic presentation shows that without perturbing force the orbits of the planets would be circles; only perturbing force could elongate the circular orbits into ellipses. Since the Hubble telescope found that the planetary orbits of other stars in the Milky Way are also ellipses, powerful perturbing force must be present in our galaxy. Such perturbing force is the Sagittarius Dwarf Galaxy with its heavy Black Hole and leftover stars, which we see orbiting around the center of our galaxy. Since observations of NASA's SDO found that magnetic fields rule the solar activity, we can expect when the planets align and their magnetic moments sum up, the already perturbed stars to reverse their magnetic parity (represented graphically as periodic looping through the hole of the torus). We predict that planets aligned on both sides of the Sun, when their magnetic moments sum-up, would induce more flares in the turbulent equatorial zone, which would bulge. When planets align only on one side of the Sun, the strong magnetic gradient of their asymmetric pull would flip the magnetic poles of the Sun. The Sun would elongate pole-to-pole, emit some energy through the poles, and the solar activity would cease. Similar reshaping and emission was observed in stars called magnetars and experimentally observed in super-liquid fast-spinning Helium nanodroplets. We are certain that NASA's SDO will confirm our predictions.

  12. Verification of high-speed solar wind stream forecasts using operational solar wind models

    Science.gov (United States)

    Reiss, Martin A.; Temmer, Manuela; Veronig, Astrid M.; Nikolic, Ljubomir; Vennerstrom, Susanne; Schöngassner, Florian; Hofmeister, Stefan J.

    2016-07-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the Advanced Composition Explorer (ACE) spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation between the coronal hole area observed in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images and solar wind properties at the near-Earth environment, the WSA model establishes a link between properties of the open magnetic field lines extending from the photosphere to the corona and the background solar wind conditions. We found that both solar wind models are capable of predicting the large-scale features of the observed solar wind speed (root-mean-square error, RMSE ≈100 km/s) but tend to either overestimate (ESWF) or underestimate (WSA) the number of high-speed solar wind streams (threat score, TS ≈ 0.37). The predicted high-speed streams show typical uncertainties in the arrival time of about 1 day and uncertainties in the speed of about 100 km/s. General advantages and disadvantages of the investigated solar wind models are diagnosed and outlined.

  13. Two-component model of solar plages

    Institute of Scientific and Technical Information of China (English)

    LI; Jianping(李建平); DING; Mingde(丁明德); FANG; Cheng(方成)

    2002-01-01

    By use of the 2-m Mcmath-Pierce telescope at Kitt Peak, the high-quality spectra of a plage with moderate brightness near the center of solar disk were obtained. The data include seven spectral lines, which are Hα, Hβ, CaII H and K lines and the infrared triplet. With the consideration of fine structures of solar plages, a two-component atmospheric model is constructed by keeping the cool component to be the quiet atmosphere. Three cases of the hot component are given for different filling factors where the temperature and density distribution are adjusted in order to reproduce the seven observed spectral profiles. We also briefly discuss the influence of the column density at the base of the corona, m0, and the macro-turbulent velocity on the required filling factor and computed profiles. The two-component model is compared with precious one-component semi-empirical models. The limitation of the model is pointed out and further improvement is indicated.

  14. Solar Panel Mathematical Modeling Using Simulink

    Directory of Open Access Journals (Sweden)

    Chandani Sharma

    2014-05-01

    Full Text Available For decades, electricity is a key driver of socio-economy development. Nowadays, in the context of competition there is a direct relationship between electricity generation and sustainable development of the country. This paper presents distinct use of a Photovoltaic array offering great potential as source of electricity. The simulation uses One-diode equivalent circuit in order to investigate I-V and P-V characteristics. The GUI model is designed with Simulink block libraries. The goals of proposed model are to perform a systematic analysis, modeling and evaluation of the key subsystems for obtaining Maximum Power Point of a solar cell. Effect of increasing number of cells is described at Standard Test Conditions by mathematical modeling of equations. It is desirable to achieve maximum power output at a minimum cost under various operating conditions. Index Terms—

  15. Elementary Students' Mental Models of the Solar System

    Science.gov (United States)

    Calderon-Canales, Elena; Flores-Camacho, Fernando; Gallegos-Cazares, Leticia

    2013-01-01

    This research project aimed to identify and analyze Mexican primary school students' ideas about the components of the solar system. In particular, this study focused on conceptions of the solar system and representations of the dynamics of the solar system based on the functional and structural models that students make in school. Using a…

  16. Model validation studies of solar systems, Phase III. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, L.J.; Winn, C.B.

    1978-12-01

    Results obtained from a validation study of the TRNSYS, SIMSHAC, and SOLCOST solar system simulation and design are presented. Also included are comparisons between the FCHART and SOLCOST solar system design programs and some changes that were made to the SOLCOST program. Finally, results obtained from the analysis of several solar radiation models are presented. Separate abstracts were prepared for ten papers.

  17. Elementary Students' Mental Models of the Solar System

    Science.gov (United States)

    Calderon-Canales, Elena; Flores-Camacho, Fernando; Gallegos-Cazares, Leticia

    2013-01-01

    This research project aimed to identify and analyze Mexican primary school students' ideas about the components of the solar system. In particular, this study focused on conceptions of the solar system and representations of the dynamics of the solar system based on the functional and structural models that students make in school. Using a…

  18. Elementary Students' Mental Models of the Solar System

    Science.gov (United States)

    Calderon-Canales, Elena; Flores-Camacho, Fernando; Gallegos-Cazares, Leticia

    2013-01-01

    This research project aimed to identify and analyze Mexican primary school students' ideas about the components of the solar system. In particular, this study focused on conceptions of the solar system and representations of the dynamics of the solar system based on the functional and structural models that students make in school. Using a…

  19. A Model fot the Sources of the Slow Solar Wind

    Science.gov (United States)

    Antiochos, S. K.; Mikic, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.

    2011-01-01

    Models for the origin of the slow solar wind must account for two seemingly contradictory observations: the slow wind has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow wind also has large angular width, up to approx.60deg, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far from the heliospheric current sheet. We then use an MHD code and MDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady solar wind, and magnetic field for a time period preceding the 2008 August 1 total solar eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow wind. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere and propose further tests of the model. Key words: solar wind - Sun: corona - Sun: magnetic topology

  20. Ionospheric measurements of relative coronal brightness during the total solar eclipses of 11 August, 1999 and 9 July, 1945

    Directory of Open Access Journals (Sweden)

    C. J. Davis

    Full Text Available Swept-frequency (1-10 MHz ionosonde measurements were made at Helston, Cornwall (50°06'N, 5°18'W during the total solar eclipse on August 11, 1999. Soundings were made every three minutes. We present a method for estimating the percentage of the ionising solar radiation which remains unobscured at any time during the eclipse by comparing the variation of the ionospheric E-layer with the behaviour of the layer during a control day. Application to the ionosonde date for 11 August, 1999, shows that the flux of solar ionising radiation fell to a minimum of 25±2% of the value before and after the eclipse. For comparison, the same technique was also applied to measurements made during the total solar eclipse of 9 July, 1945, at Sörmjöle (63°68'N, 20°20'E and yielded a corresponding minimum of 16±2%. Therefore the method can detect variations in the fraction of solar emissions that originate from the unobscured corona and chromosphere. We discuss the differences between these two eclipses in terms of the nature of the eclipse, short-term fluctuations, the sunspot cycle and the recently-discovered long-term change in the coronal magnetic field.

    Key words: Ionosphere (solar radiation and cosmic ray effects - Radio science (ionospheric physics - Solar physics, astrophysics, and astronomy (corona and transition region

  1. Verification of high-speed solar wind stream forecasts using operational solar wind models

    OpenAIRE

    Reiss, Martin A.; Temmer, Manuela; Veronig, Astrid M.; Nikolic, Ljubomir; Vennerstrom, Susanne; Schoengassner, Florian; Hofmeister, Stefan J.

    2016-01-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the ACE spacecraft for ...

  2. Modeling and analysis of solar distributed generation

    Science.gov (United States)

    Ortiz Rivera, Eduardo Ivan

    Recent changes in the global economy are creating a big impact in our daily life. The price of oil is increasing and the number of reserves are less every day. Also, dramatic demographic changes are impacting the viability of the electric infrastructure and ultimately the economic future of the industry. These are some of the reasons that many countries are looking for alternative energy to produce electric energy. The most common form of green energy in our daily life is solar energy. To convert solar energy into electrical energy is required solar panels, dc-dc converters, power control, sensors, and inverters. In this work, a photovoltaic module, PVM, model using the electrical characteristics provided by the manufacturer data sheet is presented for power system applications. Experimental results from testing are showed, verifying the proposed PVM model. Also in this work, three maximum power point tracker, MPPT, algorithms would be presented to obtain the maximum power from a PVM. The first MPPT algorithm is a method based on the Rolle's and Lagrange's Theorems and can provide at least an approximate answer to a family of transcendental functions that cannot be solved using differential calculus. The second MPPT algorithm is based on the approximation of the proposed PVM model using fractional polynomials where the shape, boundary conditions and performance of the proposed PVM model are satisfied. The third MPPT algorithm is based in the determination of the optimal duty cycle for a dc-dc converter and the previous knowledge of the load or load matching conditions. Also, four algorithms to calculate the effective irradiance level and temperature over a photovoltaic module are presented in this work. The main reasons to develop these algorithms are for monitoring climate conditions, the elimination of temperature and solar irradiance sensors, reductions in cost for a photovoltaic inverter system, and development of new algorithms to be integrated with maximum

  3. Solar activity indices as a proxy for the variation of ionospheric Total Electron Content (TEC) over Bahir Dar, Ethiopia during the year 2010-2014

    Science.gov (United States)

    Kassa, Tsegaye; Tilahun, Samson; Damtie, Baylie

    2017-09-01

    This paper was aimed at investigating the solar variations of vTEC as a function of solar activity parameters, EUV and F10.7 radio flux. The daily values of ionospheric vertical Total Electron Content (vTEC) were observed using a dual frequency GPS receiver deployed at Bahir Dar (11.6°N and 37.36°E), Ethiopia. Measurements were taken during the period of 2010-2014 for successive five years and analysis was done on only quiet day observations. A quadratic fit was used as a model to describe the daily variation of vTEC in relation to solar parameters. Linear and non-linear coefficients of the vTEC variations were calculated in order to capture the trend of the variation. The variation of vTEC have showed good agreement with the trend of solar parameters in almost all of the days we consider during the period of our observations. We have explicitly observed days with insignificant TECU deviation (eg. modeling with respect to EUV, DOY = 49 in 2010 and modeling with respect to F10.7, DOY = 125 in 2012 and the like) and days with maximum deviation (about 50 TECU). A maximum deviation were observed, on average, during months of equinox whereas minimum during solstice months. This implies that there is a need to consider more parameters, including EUV and F10.7, that can affect the variation of vTEC during equinox seasons. Relatively, small deviations was observed in modeling vTEC as a function of EUV compared to that of the variation due to F10.7 cm flux. This may also tell us that EUV can be more suitable in modeling the solar variation of vTEC especially for longterm trends. Even though, the linear trend of solar variations of vTEC was frequently observed, significant saturation and amplification trends of the solar variations of vTEC were also observed to some extent across the months of the years we have analyzed. This mixed trend of the solar variation of vTEC implies the need for thorough investigation on the effect of solar parameters on TEC. However, based on

  4. ATU/Fort Hood Solar Total Energy Military Large-Scale Experiment (LSE-1): system design and support activities. Final report, November 23, 1976-November 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    The ATU/Fort Hood Solar Total Energy System will include a concentrating solar collector field of several acres. During periods of direct insolation, a heat-transfer fluid will be circulated through the collector field and thus heated to 500 to 600/sup 0/F. Some of the fluid will be circulated through a steam generator to drive a turbine-generator set; additional fluid will be stored in insulated tanks for use when solar energy is not available. The electrical output will satisfy a portion of the electrical load at Fort Hood's 87,000 Troop Housing Complex. Heat extracted from the turbine exhaust in the form of hot water will be used for space heating, absorption air conditioning, and domestic water heating at the 87,000 Complex. Storage tanks for the hot water are also included. The systems analysis and program support activities include studies of solar availability and energy requirements at Fort Hood, investigation of interfacing LSE-1 with existing energy systems at the 87,000 Complex, and preliminary studies of environmental, health, and safety considerations. An extensive survey of available concentrating solar collectors and modifications to a computerized system simulation model for LSE-1 use are also reported. Important program support activities are military liaison and information dissemination. The engineering test program reported involved completion of the Solar Engineering Test Module (SETM) and extensive performance testing of a single module of the linear-focusing collector.

  5. Total solar eclipse education for young generation at Palangkaraya, Central Kalimantan

    Science.gov (United States)

    Fatima, S.; Widyanita; Fahriyah, H.; Rhodiyah, A. K.; Satrya, C. D.; Hilmi, M.; Ramadhania, G. E.; Naufal, L.; Mulki, F. A. M.; Herdiwijaya, D.

    2016-11-01

    The path of Total Solar Eclipse (TSE) on March 9th 2016 passed through several cities in Indonesia and one of them is Palangkaraya, Central Kalimantan. The TSE natural phenomenon provided a special moment and gave unforgettable and lifelong experiences for children who live in Palangkaraya. Some miss-information and a bad impression can be felt by children who do not understand about TSE that causes momentary darkness during totality phase. Therefore we designed a children education programs about the TSE that as follow: (1) socialization about TSE, (2) Popular astronomy seminar, (3) How to observe the Sun? (4) writing competition about TSE and (5) TSE observation. The events were held on March 8th - 9th 2016. More than 200 representatives of elementary school students and teachers throughout Palangkaraya have actively participated. The keynote speaker was an Indonesian expert astronomer with help from alumni of astronomy olympiad in order to provide inspiration for the participants, especially to the students. We conclude that students as young generation of the nation may have more motivation to work in science by direct learning from natural phenomena.

  6. The 20 March 2015 total solar eclipse: effects in the high-latitude lower ionosphere

    Science.gov (United States)

    Cherniakov, Sergey; Tereshchenko, Valentina; Ogloblina, Olga; Vasiliev, Evgeny; Gomonov, Alexander

    2016-07-01

    The medium-wave facility of partial reflections of the Polar Geophysical Institute (observatory "Tumanny", 69 N, 35.7 E) has observed behavior of the lower high-latitude ionosphere during the 20 March 2015 total solar eclipse. There were several effects during the eclipse. Generally on the heights of the lower ionosphere the "short night" effect had shown, but at some heights local enhanced electron concentration were revealed and the behavior of the electron concentration had the wave-like form. It had seen also at the behavior of the total electron content of the lower ionosphere. The periods and behavior of the wave are considered. It can be explained by influence of acoustic-gravity waves which originated after cooling of the atmosphere by the lunar shadow during its supersonic movement along the earth surface. The periods and behavior of waves during the eclipse were also received using riometer data at the observatory "Tumanny" and the magnetometer at the observatory "Loparskaya" (68.63 N, 33.38 E).

  7. The Distribution of Solar Wind Speeds During Solar Minimum: Calibration for Numerical Solar Wind Modeling Constraints on the Source of the Slow Solar Wind (Postprint)

    Science.gov (United States)

    2012-03-05

    2003) and Schwadron et al. (2005) as constraints. The new relationship was tested by using it to drive the ENLIL 3‐D MHD solar wind model and obtain...it to drive the ENLIL 3‐D MHD solar wind model and obtain solar wind parameters at Earth (1.0 AU) and Ulysses (1.4 AU). The improvements in speed...propagated out into the heliosphere using the ENLIL solar wind model . ENLIL is a 3‐D Magne- tohydrodynamic ( MHD ) model of the heliosphere [Odstrcil, 2003

  8. Modeling topographic influences on solar radiation: A manual for the SOLARFLUX Model

    Energy Technology Data Exchange (ETDEWEB)

    Rich, P.M.; Hetrick, W.A.; Saving, S.C. [Univ. of Kansas, Lawrence, KS (United States)

    1995-11-01

    SOLARFLUX is a geographical information system (GIS) based computer program (running under ARC/INFO and GRID) that models incoming solar radiation based on surface orientation (slope and aspect), solar angle (azimuth and zenith) as it shifts over time, shadows caused by topographic features, and atmospheric conditions. A convenient user interface allows specification of program parameters including latitude, time interval for simulation, file name of a topographic surface, atmospheric conditions (transmittivity), and file names for output. The user specifies a topographic surface as an array of elevation values (GRID). SOLARFLUX generates five basic types of output: 1) total direct radiation, 2) duration of direct sunlight, 3) total diffuse radiation, 4) skyview factor, and 5) hemispherical viewsheds of sky obstruction for specified surface locations. This manual serves as the comprehensive guide to SOLARFLUX. Included are discussions on modeling insolation on complex surfaces, our theoretical approach, program setup and operation, and a set of applications illustrating characteristics of topographic insolation modeling.

  9. Mars atmospheric losses induced by the solar wind: Comparison of observations with models

    Science.gov (United States)

    Vaisberg, Oleg

    2015-12-01

    With new results from Mars-Express on plasma environment of Mars and two new Mars satellites the study Martian atmospheric losses receives new attention. Paper summarizes experimental results concentrating on configuration of Martian magnetosphere and the measurements of planetary ion escape induced by the solar wind. Several plasma populations constituting solar wind induced mass loss have been identified and studied: pick-up ions in shocked solar wind flow and induced (accretion) tail, ions accelerated in the tail current sheet, and outflow of ionospheric ions. Measured ion flux values and calculations of the total escape rate including solar cycle variations are summarized. Several types of simulation of the solar wind with Mars are considered and results of representative models are given and compared with experimental results. These computer models allowed one to much better understand solar wind-Mars interaction. However, there is significant difference between total loss rates obtained from simulation and ones from measurements on the spacecraft. Both measurements and simulation provide significant flux values that are considered as an important factor of mass loss during cosmogonic time of the planet. The origin of each solar wind induced loss component and its contribution to total amount are discussed and compared with relevant computer models. Future progress in experiments and simulation is briefly discussed.

  10. Determination of time-dependent uncertainty of the total solar irradiance records from 1978 to present

    Directory of Open Access Journals (Sweden)

    Fröhlich Claus

    2016-01-01

    Full Text Available Aims. The existing records of total solar irradiance (TSI since 1978 differ not only in absolute values, but also show different trends. For the study of TSI variability these records need to be combined and three composites have been devised; however, the results depend on the choice of the records and the way they are combined. A new composite should be based on all existing records with an individual qualification. It is proposed to use a time-dependent uncertainty for weighting of the individual records. Methods. The determination of the time-dependent deviation of the TSI records is performed by comparison with the square root of the sunspot number (SSN. However, this correlation is only valid for timescales of the order of a year or more because TSI and SSN react quite differently to solar activity changes on shorter timescales. Hence the results concern only periods longer than the one-year-low-pass filter used in the analysis. Results. Besides the main objective to determine an investigator-independent uncertainty, the comparison of TSI with √SSN turns out to be a powerful tool for the study of the TSI long-term changes. The correlation of √SSN with TSI replicates very well the TSI minima, especially the very low value of the recent minimum. The results of the uncertainty determination confirm not only the need for adequate corrections for degradation, but also show that a rather detailed analysis is needed. The daily average of all TSI values available on that day, weighted with the correspondingly determined uncertainty, is used to construct a “new” composite, which, overall, compares well with the Physikalisch-Meteorologisches Observatorium Davos (PMOD composite. Finally, the TSI − √SSN comparison proves to be an important diagnostic tool not only for estimating uncertainties of observations, but also for a better understanding of the long-term variability of TSI.

  11. Solar response in tropical stratospheric ozone: a 3-D chemical transport model study using ERA reanalyses

    Directory of Open Access Journals (Sweden)

    S. Dhomse

    2011-12-01

    Full Text Available We have used an off-line 3-D chemical transport model (CTM to investigate the 11-yr solar cycle response in tropical stratospheric ozone. The model is forced with European Centre for Medium-Range Weather Forecasts (ECMWF (reanalysis (ERA-40/operational and ERA-Interim data for the 1979–2005 time period. We have compared the modelled solar response in ozone to observation-based data sets that are constructed using satellite instruments such as Total Ozone Mapping Spectrometer (TOMS, Solar Backscatter UltraViolet instrument (SBUV, Stratospheric Aerosol and Gas Experiment (SAGE and Halogen Occultation Experiment (HALOE. A significant difference is seen between simulated and observed ozone during the 1980s, which is probably due to inhomogeneities in the ERA-40 reanalyses. In general, the model with ERA-Interim dynamics shows better agreement with the observations from 1990 onwards than with ERA-40. Overall both standard model simulations are partially able to simulate a "double peak"-structured ozone solar response with a minimum around 30 km, and these are in better agreement with HALOE than SAGE-corrected SBUV (SBUV/SAGE or SAGE-based data sets. In the tropical lower stratosphere (TLS, the modelled solar response with time-varying aerosols is amplified through aliasing with a volcanic signal, as the model overestimates ozone loss during high aerosol loading years. However, the modelled solar response with fixed dynamics and constant aerosols shows a positive signal which is in better agreement with SBUV/SAGE and SAGE-based data sets in the TLS. Our model simulations suggests that photochemistry contributes to the ozone solar response in this region. The largest model-observation differences occur in the upper stratosphere where SBUV/SAGE and SAGE-based data show a significant (up to 4% solar response whereas the standard model and HALOE do not. This is partly due to a positive solar response in the ECMWF upper stratospheric temperatures which

  12. An update of Leighton's solar dynamo model

    Science.gov (United States)

    Cameron, R. H.; Schüssler, M.

    2017-02-01

    In 1969, Leighton developed a quasi-1D mathematical model of the solar dynamo, building upon the phenomenological scenario of Babcock published in 1961. Here we present a modification and extension of Leighton's model. Using the axisymmetric component (longitudinal average) of the magnetic field, we consider the radial field component at the solar surface and the radially integrated toroidal magnetic flux in the convection zone, both as functions of latitude. No assumptions are made with regard to the radial location of the toroidal flux. The model includes the effects of (i) turbulent diffusion at the surface and in the convection zone; (ii) poleward meridional flow at the surface and an equatorward return flow affecting the toroidal flux; (iii) latitudinal differential rotation and the near-surface layer of radial rotational shear; (iv) downward convective pumping of magnetic flux in the shear layer; and (v) flux emergence in the form of tilted bipolar magnetic regions treated as a source term for the radial surface field. While the parameters relevant for the transport of the surface field are taken from observations, the model condenses the unknown properties of magnetic field and flow in the convection zone into a few free parameters (turbulent diffusivity, effective return flow, amplitude of the source term, and a parameter describing the effective radial shear). Comparison with the results of 2D flux transport dynamo codes shows that the model captures the essential features of these simulations. We make use of the computational efficiency of the model to carry out an extended parameter study. We cover an extended domain of the 4D parameter space and identify the parameter ranges that provide solar-like solutions. Dipole parity is always preferred and solutions with periods around 22 yr and a correct phase difference between flux emergence in low latitudes and the strength of the polar fields are found for a return flow speed around 2 m s-1, turbulent

  13. SAMI3 prediction of the impact of the 21 August 2017 total solar eclipse on the ionosphere/plasmasphere system

    Science.gov (United States)

    Huba, J. D.; Drob, D.

    2017-06-01

    We present quantitative predictions of the impact of the upcoming total solar eclipse on the ionosphere and plasmasphere using the Naval Research Laboratory (NRL) model Sami3 is Also a Model of the Ionosphere (SAMI3). The eclipse will occur over the continental United States on 21 August 2017. Our simulation results indicate that in the vicinity of the eclipse (1) the total electron content (TEC) decreases by up to ˜ 5 TEC units (TECU; 1 TECU = ×1016 m-2) which is a ˜ 35% decrease in TEC, (2) the electron density decreases by a factor of ˜ 50% in the F region, (3) the electron temperature decreases by up to ˜800 K in the plasmasphere, and (4) the O+ velocity changes from ˜40 m s-1 upward to ˜20 m s-1 downward in the F region. Interestingly, the continental size modification of the ionospheric conductance modifies the global electric field, which should lead to measurable changes in the TEC in the southern conjugate hemisphere (≲1 TECU).

  14. Search for Rapid Changes in the Visible-Light Corona during the 21 June 2001 Total Solar Eclipse

    OpenAIRE

    Rudawy, P.; Phillips, K. J. H.; Buczylko, A.; D. R., William; F. P. Keenan

    2010-01-01

    Some 8000 images obtained with the Solar Eclipse Coronal Imaging System (SECIS) fast-frame CCD camera instrument located at Lusaka, Zambia, during the total eclipse of 21 June 2001 have been analysed to search for short-period oscillations in intensity that could be a signature of solar coronal heating mechanisms by MHD wave dissipation. Images were taken in white-light and Fe xiv green-line (5303 ) channels over 205 seconds (frame rate 39 s(-1)), approximately the length of eclipse totality ...

  15. Extreme-infrared brightness profile of the solar chromosphere obtained during the total eclipse of 1991

    Science.gov (United States)

    Lindsey, C.; Jefferies, J. T.; Clark, T. A.; Harrison, R. A.; Carter, M. K.; Watt, G.; Becklin, E. E.; Roellig, T. L.; Braun, D. C.; Naylor, D. A.

    1992-01-01

    A temperature profile in 1.3 mm radiation with about 300 km resolution at the sun was obtained during the total eclipse of 1991. The observations indicate that spicules reach a temperature of 8000 K at 3000-4000 km above the photosphere. This temperature is lower than those of many spicule models.

  16. Exploring the prominence-corona connection and its expansion into the outer corona using total solar eclipse observations

    Energy Technology Data Exchange (ETDEWEB)

    Habbal, Shadia Rifai [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Morgan, Huw [Institute of Mathematics, Physics and Computer Science, Aberystwyth University, Ceredigion, Cymru SY23 3BZ (United Kingdom); Druckmüller, Miloslav, E-mail: shadia@ifa.hawaii.edu [Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno (Czech Republic)

    2014-10-01

    Prominences constitute the most complex magnetic structures in the solar corona. The ubiquitous presence of their seemingly confined dense and cool plasma in an otherwise million-degree environment remains a puzzle. Using a decade of white light total solar eclipse observations, we show how these images reveal an intricate relationship between prominences and coronal structures both in their immediate vicinity, known as coronal cavities, and in the extended corona out to several solar radii. Observations of suspended prominences and twisted helical structures spanning several solar radii are central to these findings. The different manifestations of the prominence-corona interface that emerge from this study underscore the fundamental role played by prominences in defining and controlling the complex expansion and dynamic behavior of the solar magnetic field in the neighborhood of magnetic polarity reversal regions. This study suggests that the unraveling of prominences and the outward expansion of the helical twisted field lines linked to them could be the solar origin of twisted magnetic flux ropes detected in interplanetary space, and of the mechanism by which the Sun sheds its magnetic helicity. This work also underscores the likely role of the prominence-corona interface as a source of the slow solar wind.

  17. Modeling Scattering Polarization for Probing Solar Magnetism

    CERN Document Server

    Bueno, Javier Trujillo

    2011-01-01

    This paper considers the problem of modeling the light polarization that emerges from an astrophysical plasma composed of atoms whose excitation state is significantly influenced by the anisotropy of the incident radiation field. In particular, it highlights how radiative transfer simulations in three-dimensional models of the quiet solar atmosphere may help us to probe its thermal and magnetic structure, from the near equilibrium photosphere to the highly non-equilibrium upper chromosphere. The paper finishes with predictions concerning the amplitudes and magnetic sensitivities of the linear polarization signals produced by scattering processes in two transition region lines, which should encourage us to develop UV polarimeters for sounding rockets and space telescopes with the aim of opening up a new diagnostic window in astrophysics.

  18. Impulsive solar X-ray bursts. 4: Polarization, directivity and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    Science.gov (United States)

    Langer, S. H.; Petrosian, V.

    1976-01-01

    A Monte Carlo method is described for evaluation of the spectrum, directivity and polarization of X-rays diffusely reflected from stellar photospheres. the accuracy of the technique is evaluated through comparison with analytic results. Using the characteristics of the incident X-rays of the model for solar X-ray flares, the spectrum, directivity and polarization of the reflected and the total X-ray fluxes are evaluated. The results are compared with observations.

  19. Models and optimization of solar-control automotive glasses

    Science.gov (United States)

    Blume, Russell Dale

    Efforts to develop automotive glasses with enhanced solar control characteristics have been motivated by the desire for increased consumer comfort, reduced air-conditioning loads, and improved fuel-economy associated with a reduction in the total solar energy transmitted into the automotive interior. In the current investigation, the base soda-lime-silicate glass (72.7 wt.% SiO 2, 14.2% Na2O, 10.0% CaO, 2.5% MgO, 0.6% Al2O 3 with 0.3 Na2SO4 added to the batch as a fining agent) was modified with Fe2O3 (0.0 to 0.8%), NiO (0.0 to 0.15%), CoO (0.0 to 0.15%), V2O5 (0.0 to 0.225%), TiO2 (0.0 to 1.5%), SnO (0.0 to 3.0%), ZnS (0.0 to 0.09%), ZnO (0.0 to 2.0%), CaF2 (0.0 to 2.0%), and P2O5 (0.0 to 2.0%) to exploit reported non-linear mechanistic interactions among the dopants by which the solar-control characteristics of the base glass can be modified. Due to the large number of experimental variables under consideration, a D-optimal experimental design methodology was utilized to model the solar-optical properties as a function of batch composition. The independent variables were defined as the calculated batch concentrations of the primary (Fe2O 3, NiO, CoO, V2O5) and interactive (CaF2 , P2O5, SnO, ZnS, ZnO, TiO2) dopants in the glass. The dependent variable was defined as the apparent optical density over a wavelength range of 300--2700 nm at 10 nm intervals. The model form relating the batch composition to the apparent optical density was a modified Lambert-Beer absorption law; which, in addition to the linear terms, contained quadratic terms of the primary dopants, and a series of binary and ternary non-linear interactions amongst the primary and interactive dopants. Utilizing the developed model, exceptional fit in terms of both the discrete response (the transmission curves) and the integrated response (visible and solar transmittance) were realized. Glasses utilizing Fe2O 3, CoO, NiO, V2O5, ZnO and P2O 5 have generated innovative glasses with substantially improved

  20. Fort Hood Solar Total Energy Project. Volume II. Preliminary design. Part 2. System performance and supporting studies. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1979-01-01

    The preliminary design developed for the Solar Total Energy System to be installed at Fort Hood, Texas, is presented. System performance analysis and evaluation are described. Feedback of completed performance analyses on current system design and operating philosophy is discussed. The basic computer simulation techniques and assumptions are described and the resulting energy displacement analysis is presented. Supporting technical studies are presented. These include health and safety and reliability assessments; solar collector component evaluation; weather analysis; and a review of selected trade studies which address significant design alternatives. Additional supporting studies which are generally specific to the installation site are reported. These include solar availability analysis; energy load measurements; environmental impact assessment; life cycle cost and economic analysis; heat transfer fluid testing; meteorological/solar station planning; and information dissemination. (WHK)

  1. A self-consistent estimate of O+ + N2 − rate coefficient and total EUV solar flux with λ < 1050 Å using EISCAT observations

    Directory of Open Access Journals (Sweden)

    K. Schlegel

    Full Text Available There are differences between existing models of solar EUV with λ < 1050 Å and between laboratory measurements of the O+ + N2 – reaction rate coefficient, both parameters being crucial for the F2-region modeling. Therefore, indirect aeronomic estimates of these parameters may be useful for qualifying the existing EUV models and the laboratory measured O+ + N2 – rate coefficient. A modified self-consistent method for daytime F2-region modeling developed by Mikhailov and Schlegel was applied to EISCAT observations (32 quiet summer and equinoctial days to estimate the set of main aeronomic parameters. Three laboratory measured temperature dependencies for the O+ + N2 – rate coefficient were used in our calculations to find self-consistent factors both for this rate coefficient and for the solar EUV flux model from Nusinov. Independent of the rate coefficient used, the calculated values group around the temperature dependence recently measured by Hierl et al. in the 850–1400 K temperature range. Therefore, this rate coefficient may be considered as the most preferable and is recommended for aeronomic calculations. The calculated EUV flux shows a somewhat steeper dependence on solar activity than both, the Nusinov and the EUVAC models predict. In practice both EUV models may be recommended for the F2-region electron density calculations with the total EUV flux shifted by ±25% for the EUVAC and Nusinov models, correspondingly.Key words: Ionosphere (ion chemistry and composition; ionosphere atmosphere interactions; modeling and forecasting

  2. Instrument Description: The Total Solar Irradiance Monitor on the FY-3C Satellite, an Instrument with a Pointing System

    Science.gov (United States)

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

    2017-01-01

    The Total Solar Irradiance Monitor (TSIM) onboard the nadir Feng Yun-3C (FY-3C) satellite provides measurements of the total solar irradiance with accurate solar tracking and sound thermal stability of its heat sink. TSIM/FY-3C mainly consists of the pointing system, the radiometer package, the thermal control system, and the electronics. Accurate solar tracking is achieved by the pointing system, which greatly improves the science data quality when compared with the previous TSIM/FY-3A and TSIM/FY-3B. The total solar irradiance (TSI) is recorded by TSIM/FY-3C about 26 times each day, using a two-channel radiometer package. One channel is used to perform routine observation, and the other channel is used to monitor the degradation of the cavity detector in the routine channel. From the results of the ground test, the incoming irradiance is measured by the routine channel (AR1) with a relative uncertainty of 592 ppm. A general description of the TSIM, including the instrument modules, uncertainty evaluation, and its operation, is given in this article.

  3. Multi-site Observations of the March 2016 Total Solar Eclipse: Calibration of Images to Simulate Continuous Monitoring

    Science.gov (United States)

    Bosh, Robert; Penn, Matthew J.; McKay, Myles; Baer, Robert; Garrison, David; Gelderman, Richard; Hare, Honor; Isberner, Fred; Jensen, Logan; Kovac, Sarah; Mitchell, Adriana; Pierce, Michael; Thompson, Patricia; Ursache, Andrei; Varsik, John R.; Walter, Donald K.; Watson, Zachary; Young, David; Citizen Cate Team

    2017-01-01

    During the total solar eclipse of March 9, 2016, five teams of astronomers participating in the Citizen Continental America Telescopic Eclipse (CATE) experiment, traveled to different locations in Indonesia to observe the eclipse. Data was acquired to continuously monitor the progression of features in the inner solar corona: a region of the solar atmosphere where time evolution is not well understood. Image data from the eclipse consisted of sets of 7 exposure times 0.4, 1.3, 4, 13, 40, 130, and 400 milliseconds which are used to create a high dynamic range composite image. Eclipse data from these sites were then processed and calibrated using sets of dark and flat images. Further data processing included the compilation of exposures into high dynamic range images and were subsequently spatially filtered. Using these processing techniques, data from each site was aligned and compiled as frames in videos of the eclipse, each consisting of over 140 frames with the goal of being combined. Lessons learned from the data obtained in the observations of the 2016 total solar eclipse are being used to improve the procedure which will be used in the CATE experiment during the North American 2017 total solar eclipse.

  4. Response of atmospheric ground level temperatures to changes in the total solar irradiance

    CERN Document Server

    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...

  5. Impacts of the total solar eclipse of 9 March 2016 on meteorological parameters in Ternate

    Science.gov (United States)

    Satyaningsih, R.; Heriyanto, E.; Kadarsah; Nuraini, TA; Rizal, J.; Sopaheluwakan, A.; Aldrian, E.

    2016-11-01

    The total solar eclipse on 9th March 2016 has given a unique opportunity to assess impacts of the eclipse on various meteorological parameters in Ternate. A weather transmitter, a net radiometer, and a heat flux plate for measuring soil heat flux in bare soil were deployed during this special observation in Madaha, Ternate (0°51'17.5" N, 127°20'56.8" E). The measured meteorological parameters presented here are net radiation, air temperature, relative humidity, and soil heat flux. The results show that those parameters are significantly affected by the eclipse. The percentage of the observed decrease of net radiation during the eclipse was proportional to the obscuration percentage. The air temperature measured at 1.5 m declined around 1.9 °C with approximately 11 minutes lag between the mid-eclipse and minimum temperature during eclipse. Influences from the surrounding environment in the measurement site minimize the temperature response. As a consequence of temperature decrease, relative humidity increased. A drop in soil heat flux was also detected but its response was slower.

  6. UNAWE Indonesia project: raising total solar eclipse 2016 awareness through educational packages

    Science.gov (United States)

    Handini, A. T.; Yulianty, Y.; Premadi, P. W.; Annafi, A.

    2016-11-01

    On March 9th 2016, some regions in Indonesia witnessed the Total Solar Eclipse (TSE). At that time, Indonesia was the only mainland in the world that could observe TSE. This moment is extraordinary because its probability of being observed at the same point happens every 350 years. On a purpose of raising public awareness and engaging more participations, UNAWE Indonesia developed a handy material and sent the so called educational packages which provided essential information about eclipse, especially TSE. Each package contains of modul of TSE study and materials for simple TSE activity so people who received the package could observe TSE safely. In the delivery of this program, we established a collaboration partner, whom are teachers, as an 'eclipse ambassador'. The local partners were responsible for socializing the information for school or their community. We encouraged them to conduct an observation activity and ask them to fill an evaluation report. As a result, 48 out of 59 partners or equal to 81.3% of all partners has sent the evaluation of the package and documentation of the activity during TSE. They responded positively as it was easy to understand, functional, and convenient.

  7. Multithread Hydrodynamic Modeling of a Solar Flare

    Science.gov (United States)

    Warren, Harry P.

    2006-01-01

    Past hydrodynamic simulations have been able to reproduce the high temperatures and densities characteristic of solar flares. These simulations, however, have not been able to account for the slow decay of the observed flare emission or the absence of blueshifts in high spectral resolution line profiles. Recent work has suggested that modeling a flare as a sequence of independently heated threads instead of as a single loop may resolve the discrepancies between the simulations and observations. In this paper, we present a method for computing multithread, time-dependent hydrodynamic simulations of solar flares and apply it to observations of the Masuda flare of 1992 January 13. We show that it is possible to reproduce the temporal evolution of high temperature thermal flare plasma observed with the instruments on the GOES and Yohkoh satellites. The results from these simulations suggest that the heating timescale for a individual thread is on the order of 200 s. Significantly shorter heating timescales (20 s) lead to very high temperatures and are inconsistent with the emission observed by Yohkoh.

  8. Implementation of Bessel's method for solar eclipses prediction in the WRF-ARW model

    Science.gov (United States)

    Montornes, Alex; Codina, Bernat; Zack, John W.; Sola, Yolanda

    2016-05-01

    Solar eclipses are predictable astronomical events that abruptly reduce the incoming solar radiation into the Earth's atmosphere, which frequently results in non-negligible changes in meteorological fields. The meteorological impacts of these events have been analyzed in many studies since the late 1960s. The recent growth in the solar energy industry has greatly increased the interest in providing more detail in the modeling of solar radiation variations in numerical weather prediction (NWP) models for the use in solar resource assessment and forecasting applications. The significant impact of the recent partial and total solar eclipses that occurred in the USA (23 October 2014) and Europe (20 March 2015) on solar power generation have provided additional motivation and interest for including these astronomical events in the current solar parameterizations.Although some studies added solar eclipse episodes within NWP codes in the 1990s and 2000s, they used eclipse parameterizations designed for a particular case study. In contrast to these earlier implementations, this paper documents a new package for the Weather Research and Forecasting-Advanced Research WRF (WRF-ARW) model that can simulate any partial, total or hybrid solar eclipse for the period 1950 to 2050 and is also extensible to a longer period. The algorithm analytically computes the trajectory of the Moon's shadow and the degree of obscuration of the solar disk at each grid point of the domain based on Bessel's method and the Five Millennium Catalog of Solar Eclipses provided by NASA, with a negligible computational time. Then, the incoming radiation is modified accordingly at each grid point of the domain.This contribution is divided in three parts. First, the implementation of Bessel's method is validated for solar eclipses in the period 1950-2050, by comparing the shadow trajectory with values provided by NASA. Latitude and longitude are determined with a bias lower than 5 x 10-3 degrees (i

  9. A Physics-based Analytical Model for Perovskite Solar Cells

    OpenAIRE

    Sun, Xingshu; Asadpour, Reza; Nie, Wanyi; Mohite, Aditya D.; Alam, Muhammad A.

    2015-01-01

    Perovskites are promising next-generation absorber materials for low-cost and high-efficiency solar cells. Although perovskite cells are configured similar to the classical solar cells, their operation is unique and requires development of a new physical model for characterization, optimization of the cells, and prediction of the panel performance. In this paper, we develop such a physics-based analytical model to describe the operation of different types of perovskite solar cells, explicitly...

  10. SELCO: A model for solar rural electrification in India

    Science.gov (United States)

    Hande, H. Harish

    1999-11-01

    The following thesis presents the concept of a Rural Energy Service Company in India, known as SELCO. The model is being set up as a sustainable proposition for the implementation of solar photovoltaics as a viable alternative to provide reliable home lighting in the rural areas of India. The SELCO approach has already achieved noteworthy social and commercial results. Institutional, policy and operational problems have long plagued the rural electrification programs in India, resulting in thousands of villages without access to electricity. SELCO is a solar energy service company operating in Southern India since 1995, focusing on the enormous untapped market for home lighting where thousands of households have no access to electricity and severe power shortages face those already connected to the electric grid. The Company has installed nearly 2,000 solar home lighting systems. From a modest two employees company in 1995, it has grown to 35 in 1997 and from one office to eight. The hypothesis to be tested in this study is that in rural India, in a market not subsidized by the government, a solar service company with available loans from local banks and cooperatives and with sales, installation, and maintenance personnel in the villages can be successful in introducing photovoltaic systems to provide basic amenities such as lighting and water pumping for the improvement of the quality of life, public health, and the environment. The initial success of SELCO lends considerable evidence to the acceptance of the hypothesis. To accomplish its mission, SELCO works with commercial, retail, and rural development banks with large rural branch networks to stimulate loans to SELCO's customers based on a standard set of attractive financing terms. SELCO through its successful model has convinced the policy makers that a way to increase rural families' access to consumer financing for solar home lighting systems is through the existing financial network available in the

  11. Structure, Dynamics, and Spectra of the Solar Corona at the 2013 and 2015 Total Eclipses and Plans for 2017's American Totality

    Science.gov (United States)

    Pasachoff, Jay M.; Dantowitz, Ronald; Voulgaris, Aristeidis

    2016-01-01

    We observed the total solar eclipses of 3 November 2013 from Gabon and of 20 March 2015 from Svalbard in clear skies with cameras to image the solar corona at high resolution and with spectrographs for coronal emission lines. We report on the composite images showing coronal structure and (in comparison with other sites' images) dynamics, as well as the relation of our inner- and middle-corona composite images with surface EUV images from SDO and SWAP and with the outer-corona images from the coronagraphs on SOHO/LASCO. Our spectra show not only the common forbidden lines of Fe XIV (green line) and Fe X (red line) but also rarer species such as Ca XV. Finally, we describe our planned suite of observations for the 21 August 2017 solar eclipse, whose path of totality will cross the United States from Pacific to Atlantic, with more-favorable cloudiness statistics for western sites.Our Gabon and Svalbard expeditions were supported by grants from the Committee for Research and Exploration of the National Geographic Society.

  12. Final Technical Report Advanced Solar Resource Modeling and Analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The SunShot Initiative coordinates research, development, demonstration, and deployment activities aimed at dramatically reducing the total installed cost of solar power. The SunShot Initiative focuses on removing critical technical and non-technical barriers to installing and integrating solar energy into the electricity grid. Uncertainty in projected power and energy production from solar power systems contributes to these barriers by increasing financial risks to photovoltaic (PV) deployment and by exacerbating the technical challenges to integration of solar power on the electricity grid.

  13. A new regional total electron content empirical model in northeast China

    Science.gov (United States)

    Feng, Jiandi; Wang, Zhengtao; Jiang, Weiping; Zhao, Zhenzhen; Zhang, Bingbing

    2016-10-01

    Using total electron content (TEC) data over one and a half solar cycles (1999-2015) provided by the Center for Orbit Determination in Europe (CODE), this paper proposes a new empirical TEC model for northeast China (40-50N, 120-130E). The model, called TECM-NEC, involves the multiplication of four separable components, including diurnal variation, seasonal variation, geomagnetic field dependency, and solar dependency. Diurnal variation is composed of three parts: the typical daily variation of TEC; corrections of Mid-latitude Summer Nighttime Anomaly (MSNA) that depend on geographic location, season, and local time; and corrections of day-to-night ratio under different seasons and solar activities. Four sub-harmonics of the year with annual, semiannual, four-, and three-month periods are used to describe seasonal variations. For geomagnetic variation, geomagnetic latitude is based on the latest International Geomagnetic Reference Field (IGRF12) model. Compared with similar empirical models, the solar proxy index F10.7P = (F10.7 + F10.7A)/2, where F10.7A is the 81-day running mean of daily F10.7, is chosen as having linear relationship with TEC for the model. This model has 43 coefficients, which are determined by nonlinear least squares fitting (NLSF) technique. The TECM-NEC model fits with the TEC/CODE input data with a bias of 0.03TECU and a RMS deviation of 2.76TECU. The proposed TECM-NEC model can reproduce the MSNA and nighttime TEC enhancements phenomenon over northeast China.

  14. Photoproduction models for total cross section and shower development

    Science.gov (United States)

    Cornet, Fernando; Garcia Canal, Carlos; Grau, Agnes; Pancheri, Giulia; Sciutto, Sergio

    2015-08-01

    A model for the total photoproduction cross section, based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.

  15. Photoproduction models for total cross section and shower development

    CERN Document Server

    Cornet, Fernando; Grau, Agnes; Pancheri, Giulia; Sciutto, Sergio

    2014-01-01

    A model for the total photoproduction cross section based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.

  16. Photoproduction models for total cross section and shower development

    Directory of Open Access Journals (Sweden)

    Cornet Fernando

    2015-01-01

    Full Text Available A model for the total photoproduction cross section, based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.

  17. Solar Coronal Jets: Observations, Theory, and Modeling

    CERN Document Server

    Raouafi, N E; Pariat, E; Young, P R; Sterling, A C; Savcheva, A; Shimojo, M; Moreno-Insertis, F; DeVore, C R; Archontis, V; Török, T; Mason, H; Curdt, W; Meyer, K; Dalmasse, K; Matsui, Y

    2016-01-01

    Coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of significant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of "nominal" solar flares and coronal mass ejections (CMEs), jets share many common properties with these phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients close or at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broad range of solar-heliospheric problems.

  18. Surface-effect corrections for the solar model

    CERN Document Server

    Magic, Zazralt

    2016-01-01

    Solar p-mode oscillations exhibit a systematic offset towards higher frequencies due to shortcomings in the 1D stellar structure models, especially, the lack of turbulent pressure in the superadiabatic layers just below the optical surface, arising from the convective velocity field. We study the influence of the turbulent expansion, chemical composition, and magnetic fields on the stratification in the upper layers of the solar models in comparison with solar observations. Furthermore, we test alternative averages for improved results on the oscillation frequencies. We appended temporally and spatially averaged stratifications to 1D models to compute adiabatic oscillation frequencies that we then tested against observations. We also developed depth-dependent corrections for the solar 1D model, for which we expanded the geometrical depth to match the pressure stratification of the solar model, and we reduced the density that is caused by the turbulent pressure. We obtain the same results with our models a...

  19. A Model for the Sources of the Slow Solar Wind

    Science.gov (United States)

    Antiochos, Spiro K.; Mikic, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.

    2010-01-01

    Models for the origin of the slow solar wind must account for two seemingly contradictory observations: The slow wind has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow wind has large angular width, up to approximately 60 degrees, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far front the heliospheric current sheet. We then use an MHD code and MIDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady solar wind and magnetic field for a time period preceding the August 1, 2008 total solar eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow wind. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere, and propose further tests of the model.

  20. Verification of high-speed solar wind stream forecasts using operational solar wind models

    DEFF Research Database (Denmark)

    Reiss, Martin A.; Temmer, Manuela; Veronig, Astrid M.

    2016-01-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate...... high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the Advanced Composition Explorer (ACE) spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation...... between the coronal hole area observed in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images and solar wind properties at the near-Earth environment, the WSA model establishes a link between properties of the open magnetic field lines extending from the photosphere to the corona...

  1. The Eclipse, the Astronomer and His Audience: Frederico Oom and the Total Solar Eclipse of 28 May 1900 in Portugal

    Science.gov (United States)

    Carolino, Luis Miguel; Simoes, Ana

    2012-01-01

    This study offers a detailed analysis of an episode of the popularization of astronomy which took place in Portugal, a peripheral country of Europe, and occurring in the early twentieth century. The episode was driven by the 28 May 1900 total solar eclipse which was seen on the Iberian Peninsula (Portugal and Spain). Instead of focusing on one of…

  2. Total solar eclipse of 16 February 1980 and the vertical profiles of atmospheric parameters in the lowest 200M

    Digital Repository Service at National Institute of Oceanography (India)

    RameshBabu, V.; Sastry, J.S.

    Vertical profiles of air temperature, wind and humidity at Raichur (16 degrees 12'N and 77 degrees 21'E) in the lowest 200m of the atmosphere are presented for the period 15-18 February 1980. The effect of the total solar eclipse, on 16 February...

  3. The Eclipse, the Astronomer and His Audience: Frederico Oom and the Total Solar Eclipse of 28 May 1900 in Portugal

    Science.gov (United States)

    Carolino, Luis Miguel; Simoes, Ana

    2012-01-01

    This study offers a detailed analysis of an episode of the popularization of astronomy which took place in Portugal, a peripheral country of Europe, and occurring in the early twentieth century. The episode was driven by the 28 May 1900 total solar eclipse which was seen on the Iberian Peninsula (Portugal and Spain). Instead of focusing on one of…

  4. Solar system tests of brane world models

    CERN Document Server

    Boehmer, Christian G; Lobo, Francisco S N

    2008-01-01

    The classical tests of general relativity (perihelion precession, deflection of light, and the radar echo delay) are considered for the Dadhich, Maartens, Papadopoulos and Rezania (DMPR) solution of the spherically symmetric static vacuum field equations in brane world models. For this solution the metric in the vacuum exterior to a brane world star is similar to the Reissner-Nordstrom form of classical general relativity, with the role of the charge played by the tidal effects arising from projections of the fifth dimension. The existing observational solar system data on the perihelion shift of Mercury, on the light bending around the Sun (obtained using long-baseline radio interferometry), and ranging to Mars using the Viking lander, constrain the numerical values of the bulk tidal parameter and of the brane tension.

  5. Theoretical model of a photoelectrochemical solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.; Singh, S.L.; Khare, N.

    1986-03-01

    A Schottky barrier theoretical model for explaining the J-V characteristic of a photoelectrochemical solar cell (PESC) has been developed considering the effect of dark current, space-charge recombination, surface states, and detailed charge transfer kinetics at the interface. Both isoenergetic charge transfer and inelastic charge transfers (via surface states) at the interface have been considered and their relative importance are discussed. The theory has been applied to explain the (a) J-V characteristic for n-GaAs/SeS , SeS 2 junction and (b) Fermi-level pinning observed in GaAs PESC. The inelastic charge transfer via surfaces states has been shown to play an important role in deciding these characteristics.

  6. A UNIFIED MODEL FOR SOLAR FLARES

    Institute of Scientific and Technical Information of China (English)

    ChenPengfei; FangCheng; DingMingde; TangYuhua

    1999-01-01

    We performed 2.5 - dimensional numerical simulation for two cases, one with the the reconnection point at a high altitude, the other with the reconnection point at a low altitude, in the high-altitude case, the bright loop appears to rise for a long time, with its two footpoints separating and the field lines below the bright loop shrinking,which are all typical features of two - ribbon flares. In the low- altitude case, the bright loops cease rising only a short time after the impulsive phase of the reconnection and then become rather stable, which shows a large similarity to the compact flares. The results imply that the two types of solar flares, i. e., the two - ribbon flares and the compact ones, might be unified into the same magnetic reconnection model, where the height of the reconnection point leads to the bifurcation.

  7. Solar system tests of brane world models

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, Christian G [Department of Mathematics, University College London, Gower Street, London WC1E 6BT (United Kingdom); Harko, Tiberiu [Department of Physics and Center for Theoretical and Computational Physics, University of Hong Kong, Pok Fu Lam Road (Hong Kong); Lobo, Francisco S N [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 2EG (United Kingdom)], E-mail: c.boehmer@ucl.ac.uk, E-mail: harko@hkucc.hku.hk, E-mail: francisco.lobo@port.ac.uk

    2008-02-21

    The classical tests of general relativity (perihelion precession, deflection of light and the radar echo delay) are considered for the Dadhich, Maartens, Papadopoulos and Rezania (DMPR) solution of the spherically symmetric static vacuum field equations in brane world models. For this solution the metric in the vacuum exterior to a brane world star is similar to the Reissner-Nordstroem form of classical general relativity, with the role of the charge played by the tidal effects arising from projections of the fifth dimension. The existing observational solar system data on the perihelion shift of Mercury, on the light bending around the Sun (obtained using long-baseline radio interferometry), and ranging to Mars using the Viking lander, constrain the numerical values of the bulk tidal parameter and of the brane tension.

  8. Operation of the computer model for microenvironment solar exposure

    Science.gov (United States)

    Gillis, J. R.; Bourassa, R. J.; Gruenbaum, P. E.

    1995-01-01

    A computer model for microenvironmental solar exposure was developed to predict solar exposure to satellite surfaces which may shadow or reflect on one another. This document describes the technical features of the model as well as instructions for the installation and use of the program.

  9. INTEGRATED MODEL OF A SOLAR CHIMNEY EQUIPPED WITH AXIAL TURBINES

    OpenAIRE

    2015-01-01

    An integrated model of solar chim??ney (solar collector; turbine; tower) is presented; validated against data of the Manzanares plant; extended to the case of a 1000m tower. The model includes off-design performance of collector/turbine.

  10. Mathematical and computational modeling simulation of solar drying Systems

    Science.gov (United States)

    Mathematical modeling of solar drying systems has the primary aim of predicting the required drying time for a given commodity, dryer type, and environment. Both fundamental (Fickian diffusion) and semi-empirical drying models have been applied to the solar drying of a variety of agricultural commo...

  11. FIRST NEW SOLAR MODELS WITH OPAS OPACITY TABLES

    Energy Technology Data Exchange (ETDEWEB)

    Le Pennec, M.; Turck-Chièze, S.; Salmon, S. [CEA/IRFU/Service d’Astrophysique, CE Saclay, F-91191 Gif sur Yvette (France); Blancard, C.; Cossé, P.; Faussurier, G.; Mondet, G. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2015-11-10

    Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However, the particular case of the Sun is still challenging. For about a decade now, the helioseismic sound-speed determination has continued to disagree with the standard solar model (SSM) prediction, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this Letter, we use the new OPAS opacity tables, recently available for solar modeling, to address this issue. We discuss first the peculiarities of these tables, then we quantify their impact on the solar sound-speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes, Modules for Experiments in Stellar Astrophysics and Code Liégeois d’Evolution Stellaire, that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models are computed for the most recent photospheric composition with OPAS tables and present improvements to the location of the base of the convective zone and to the description of the solar radiative zone in comparison to the helioseismic observations, even if the differences in the Rosseland mean opacity do not exceed 6%. We finally carry out a comparison to a solar model computed with the OP opacity tables.

  12. Performance of the meteorological radiation model during the solar eclipse of 29 March 2006

    Directory of Open Access Journals (Sweden)

    B. E. Psiloglou

    2007-12-01

    Full Text Available Various solar broadband models have been developed in the last half of the 20th century. The driving demand has been the estimation of available solar energy at different locations on earth for various applications. The motivation for such developments, though, has been the ample lack of solar radiation measurements at global scale. Therefore, the main goal of such codes is to generate artificial solar radiation series or calculate the availability of solar energy at a place.

    One of the broadband models to be developed in the late 80's was the Meteorological Radiation Model (MRM. The main advantage of MRM over other similar models was its simplicity in acquiring and using the necessary input data, i.e. air temperature, relative humidity, barometric pressure and sunshine duration from any of the many meteorological stations.

    The present study describes briefly the various steps (versions of MRM and in greater detail the latest version 5. To show the flexibility and great performance of the MRM, a harsh test of the code under the (almost total solar eclipse conditions of 29 March 2006 over Athens was performed and comparison of its results with real measurements was made. From this hard comparison it is shown that the MRM can simulate solar radiation during a solar eclipse event as effectively as on a typical day. Because of the main interest in solar energy applications about the total radiation component, MRM focuses on that. For this component, the RMSE and MBE statistical estimators during this study were found to be 7.64% and −1.67% on 29 March as compared to the respective 5.30% and +2.04% for 28 March. This efficiency of MRM even during an eclipse makes the model promising for easy handling of typical situations with even better results.

  13. Attenuation of global ultraviolet and visible irradiance over Greece during the total solar eclipse of 29 March 2006

    Directory of Open Access Journals (Sweden)

    A. Kazantzidis

    2007-12-01

    Full Text Available The variability of ultraviolet and photosynthetically active radiation (PAR during the total solar eclipse of 29 March 2006 was examined in this study. The measurements from NILU-UV multichannel radiometers at 7 stations of the Greek UV Network were used, where the maximum eclipse percentage ranged from 73.1% to 94.8%. In addition, an extra instrument was established at a remote Greek island, Kastelorizo, which was within the Moon's umbral shadow. The reduction of irradiance at 305 and 312 nm relative to non-eclipse conditions at all sites was almost 1.5 times more than the corresponding decrease in the UVA and visible part of the spectrum and reached 98% for eclipse percentage equal to 94%. The availability of several instruments in close proximity to the path of the umbral shadow provided a challenging test for the models. The measured changes in UV and visible irradiance were compared with 1-D model calculations accounting for the limb darkening effect. The agreement between measurements and modeled values at all sites is within 3% for eclipse percentages of less than 30% and becomes worse as the eclipse progresses. The 1-D model reproduced the spectral effect of the eclipse in UVA and PAR wavelength regions within 3% for eclipse percentages up to 50%, but only the half of the observed change was captured as the eclipse progressed. At three sites, where the eclipse maximum was more than 94%, the measured irradiance at 305 nm for eclipse percentages of more than 85% decreased with slower rates than for longer wavelengths. As a result, the total ozone values, derived from the 305/320 nm ratios, apparently decreased significantly for high eclipse percentages. The effect is similar at all three sites, but the interpretation of this observation remains a challenge. Comparison results with 3-D model calculations shortly before, during and shortly after totality were performed for the first time and revealed an agreement with measurements

  14. Variation of incoming solar radiation flux during a partial eclipse episode: an improved model simulation

    CERN Document Server

    Petkov, Boyan; Vitale, Vito; Lanconelli, Christian; Mazzola, Mauro

    2011-01-01

    Model simulations of solar irradiance reaching the Earth's surface during a solar eclipse constitute a useful tool for studying the impact of this phenomenon on the radiance propagation through the atmosphere. A simple approach to extend the use of an algorithm already adopted for evaluating the variations in the extraterrestrial solar radiation during a total eclipse is proposed for a partial eclipse case. The application is based on the assessment of the distance between the apparent solar and lunar disk centers on the celestial hemisphere, using the local circumstances and the ratio between the Sun and Moon radii as input parameters. It was found that during the eclipse of March 29, 2006, the present approach led to an estimate of the surface UV solar irradiance trend differing by no more than \\pm5% from the corresponding trend observed at Bologna (Italy).

  15. Predicting Solar Cycle 25 using Surface Flux Transport Model

    Science.gov (United States)

    Imada, Shinsuke; Iijima, Haruhisa; Hotta, Hideyuki; Shiota, Daiko; Kusano, Kanya

    2017-08-01

    It is thought that the longer-term variations of the solar activity may affect the Earth’s climate. Therefore, predicting the next solar cycle is crucial for the forecast of the “solar-terrestrial environment”. To build prediction schemes for the next solar cycle is a key for the long-term space weather study. Recently, the relationship between polar magnetic field at the solar minimum and next solar activity is intensively discussed. Because we can determine the polar magnetic field at the solar minimum roughly 3 years before the next solar maximum, we may discuss the next solar cycle 3years before. Further, the longer term (~5 years) prediction might be achieved by estimating the polar magnetic field with the Surface Flux Transport (SFT) model. Now, we are developing a prediction scheme by SFT model as a part of the PSTEP (Project for Solar-Terrestrial Environment Prediction) and adapting to the Cycle 25 prediction. The predicted polar field strength of Cycle 24/25 minimum is several tens of percent smaller than Cycle 23/24 minimum. The result suggests that the amplitude of Cycle 25 is weaker than the current cycle. We also try to obtain the meridional flow, differential rotation, and turbulent diffusivity from recent modern observations (Hinode and Solar Dynamics Observatory). These parameters will be used in the SFT models to predict the polar magnetic fields strength at the solar minimum. In this presentation, we will explain the outline of our strategy to predict the next solar cycle and discuss the initial results for Cycle 25 prediction.

  16. Development of a Stochastic Hourly Solar Irradiation Model

    Directory of Open Access Journals (Sweden)

    Kristijan Brecl

    2014-01-01

    Full Text Available We have developed a new solar irradiation model and implemented it in the SunIrradiance photovoltaic cell/module simulator. This model uses stochastic methods to generate the hourly distribution of solar irradiation on a horizontal or inclined surface from monthly irradiation values on the horizontal surface of a selected location and was verified with the measured irradiance data in Ljubljana, located in Central Europe. The new model shows better simulation results with regard to the share of the diffuse irradiation in the region than the other models. The simulation results show that the new solar irradiation model is excellent for photovoltaic system simulations of single junction PV technologies.

  17. When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study.

    Science.gov (United States)

    Haidari, Leila A; Brown, Shawn T; Wedlock, Patrick; Connor, Diana L; Spiker, Marie; Lee, Bruce Y

    2017-04-19

    Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as "electric refrigerators") at different locations in the supply chain under various circumstances. At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar refrigerator prices. Copyright © 2017. Published

  18. When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study☆

    Science.gov (United States)

    Haidari, Leila A.; Brown, Shawn T.; Wedlock, Patrick; Connor, Diana L.; Spiker, Marie; Lee, Bruce Y.

    2017-01-01

    Background Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Methods Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as “electric refrigerators”) at different locations in the supply chain under various circumstances. Results At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Conclusion Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar

  19. The Efficacy of the Total Giftedness Development Model

    Science.gov (United States)

    Batterjee, Adel A.

    2010-01-01

    The study objective was to apply the Total Giftedness Development Model (TGDM) among a Saudi Arabian sample and study its effectiveness. The descriptive and case study research methods were applied on a sample of 807 male students, age 5 to 18 to test the efficacy of the model. Several instruments, including The Saudi Mental Abilities Test,…

  20. Alive and well: a short review about standard solar models

    CERN Document Server

    Serenelli, Aldo

    2016-01-01

    Standard solar models (SSMs) provide a reference framework across a number of research fields: solar and stellar models, solar neutrinos, particle physics the most conspicuous among them. The accuracy of the physical description of the global properties of the Sun that SSMs provide has been challenged in the last decade by a number of developments in stellar spectroscopic techniques. Over the same period of time, solar neutrino experiments, and Borexino in particular, have measured the four solar neutrino fluxes from the pp-chains that are associated with 99\\% of the nuclear energy generated in the Sun. Borexino has also set the most stringent limit on CNO energy generation, only $\\sim 40\\%$ larger than predicted by SSMs. More recently, and for the first time, radiative opacity experiments have been performed at conditions that closely resemble those at the base of the solar convective envelope. In this article, we review these developments and discuss the current status of SSMs, including its intrinsic limit...

  1. Alive and well: A short review about standard solar models

    Energy Technology Data Exchange (ETDEWEB)

    Serenelli, Aldo [Campus UAB, Carrer de Can Magrans S/N, Instituto de Ciencias del Espacio (ICE/CSIC-IEEC), Cerdanyola del Valles (Spain)

    2016-04-15

    Standard solar models (SSMs) provide a reference framework across a number of research fields: solar and stellar models, solar neutrinos, particle physics the most conspicuous among them. The accuracy of the physical description of the global properties of the Sun that SSMs provide has been challenged in the last decade by a number of developments in stellar spectroscopic techniques. Over the same period of time, solar neutrino experiments, and Borexino in particular, have measured the four solar neutrino fluxes from the pp-chains that are associated with 99% of the nuclear energy generated in the Sun. Borexino has also set the most stringent limit on CNO energy generation, only ∝ 40% larger than predicted by SSMs. More recently, and for the first time, radiative opacity experiments have been performed at conditions that closely resemble those at the base of the solar convective envelope. In this article, we review these developments and discuss the current status of SSMs, including its intrinsic limitations. (orig.)

  2. Analysis, Modeling and Optimum Design of Solar Domestic Hot Water Systems

    DEFF Research Database (Denmark)

    Qin, Lin

    1999-01-01

    This study focus on the analysis, modeling and simulation of solar domestic hot water(DHW) systems. Problems related to the system operation such as input weather data and hot water load conditions are also investigated.In order to investigate the heat loss as part of the total heat load, dynamic...... model of distribution network is developed and simulations are carried out for typical designed circulation type of distribution networks. For dynamic simulation of thermosyphon and drain-back solar DHW systems, thermosyphon loop model and drain-back tank model are put forward. Based on the simulations...

  3. Development of Solar Drying Model for Selected Cambodian Fish Species

    Directory of Open Access Journals (Sweden)

    Anna Hubackova

    2014-01-01

    Full Text Available A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R2, chi-square (χ2 test, and root-mean-square error (RMSE, the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  4. Development of solar drying model for selected Cambodian fish species.

    Science.gov (United States)

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6 °C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg · h(-1). Based on coefficient of determination (R(2)), chi-square (χ(2)) test, and root-mean-square error (RMSE), the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  5. Effects of various solar indices on accuracy of Earth’s thermospheric neutral density models

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Four kinds of solar indices F10.7, E10.7, S10, Mg10 and four thermospheric neutral density models, i.e., CIRA72, DTM94, NRLMSISE00 and JB2006, are discussed. The CHAMP accelerometer data are used to calculate thermospheric total mass density. Based on the comparison of the model densities with CHAMP observations, the effects of various indices on the model accuracy are detected. It is found that under quiet and moderate solar conditions (F10.7<160), all of the models’ errors are reduced about 15% by using E10.7 instead of F10.7, while under active solar conditions (F10.7>200) the error’s standard deviation using E10.7 increases quickly and causes the models’ accuracy to fall down. With regard to S10, Mg10, their effects under quiet solar conditions are inconspicuous. If under active solar conditions, they can reduce the model error’s standard deviation by 5%-10%, implying that S10, Mg10 make the model error more stable. The JB2006 model, which was constructed by multi-solar-index (F10.7, S10, Mg10), is compared with DTM94 and NRLMSISE00 based on single-solar-index. It is found that JB2006’s accuracy is better than DTM94’s, and is close to NRLMSISE00 under the quiet solar condition. During the solar burst occurring on October 26, 2003, JB2006 has been in best agreement with CHAMP observations. All in all, the new indices may improve thermospheric density models’ accuracy under some special conditions. Concretely, E10.7 may reduce the average error of models and S10, Mg10 may prevent the error’s divergence.

  6. Depth profile by Total IBA in perovskite active layers for solar cells

    Science.gov (United States)

    Barreiros, M. A.; Alves, L. C.; Brites, M. J.; Corregidor, V.

    2017-08-01

    In recent years the record efficiency of perovskite solar cells (PSCs) has been updated exceeding now 20%. However, it is difficult to make PSCs consistently. Definite correlation has been established between the PSC performance and the perovskite film quality which involves mainly morphology, crystallinity and composition. The manufacturing development of these devices is dependent on the characterisation methodologies, on the availability of suitable and reliable analytical techniques to assess the materials composition and quality and on the relationship of these results with the cell performance. Ion beam analytical (IBA) techniques jointly with a micro-ion beam are powerful tools for materials characterisation and can provide a valuable input for the knowledge of perovskite films. Perovskite films based on CH3NH3PbI3 were prepared (from CH3NH3I and PbI2 precursors) in a planar architecture and in a mesoporous TiO2 scaffold. Proton and helium micro-beams at different energies were used in the analysis of PSC active layers, previously characterised by SEM-FEG (Scanning Electron Microscopy with a field emission gun) and XRD (X-ray diffraction). Self-consistent fit of all the obtained PIXE (Particle Induced X-ray Emission) and RBS (Rutherford Backscattering Spectrometry) spectra through Total IBA approach provided depth profiling of perovskite, its precursors and TiO2 and assess their distribution in the films. PbI2 presence and location on the active layer may hinder the charge transport and highly affect the cell performance. IBA techniques allowed to identify regions of non-uniform surface coverage and homogeneous areas and it was possible to establish the undesired presence of PbI2 and its quantitative depth profile in the planar architecture film. In the mesostructured perovskite film it was verified a non-homogeneous distribution with a decreasing of perovskite concentration down to the thin blocking layer. The good agreement between the best fits obtained

  7. Solar Spectral Irradiance Variability in Cycle 24: Observations and Models

    CERN Document Server

    Marchenko, S V; Lean, J L

    2016-01-01

    Utilizing the excellent stability of the Ozone Monitoring Instrument (OMI), we characterize both short-term (solar rotation) and long-term (solar cycle) changes of the solar spectral irradiance (SSI) between 265-500 nm during the on-going Cycle 24. We supplement the OMI data with concurrent observations from the GOME-2 and SORCE instruments and find fair-to-excellent, depending on wavelength, agreement among the observations and predictions of the NRLSSI2 and SATIRE-S models.

  8. Ensemble prediction model of solar proton events associated with solar flares and coronal mass ejections

    Institute of Scientific and Technical Information of China (English)

    Xin Huang; Hua-Ning Wang; Le-Ping Li

    2012-01-01

    An ensemble prediction model of solar proton events (SPEs),combining the information of solar flares and coronal mass ejections (CMEs),is built.In this model,solar flares are parameterized by the peak flux,the duration and the longitude.In addition,CMEs are parameterized by the width,the speed and the measurement position angle.The importance of each parameter for the occurrence of SPEs is estimated by the information gain ratio.We find that the CME width and speed are more informative than the flare's peak flux and duration.As the physical mechanism of SPEs is not very clear,a hidden naive Bayes approach,which is a probability-based calculation method from the field of machine learning,is used to build the prediction model from the observational data.As is known,SPEs originate from solar flares and/or shock waves associated with CMEs.Hence,we first build two base prediction models using the properties of solar flares and CMEs,respectively.Then the outputs of these models are combined to generate the ensemble prediction model of SPEs.The ensemble prediction model incorporating the complementary information of solar flares and CMEs achieves better performance than each base prediction model taken separately.

  9. Model development and validation of a solar cooling plant

    Energy Technology Data Exchange (ETDEWEB)

    Zambrano, Darine; Garcia-Gabin, Winston [Escuela de Ingenieria Electrica, Facultad de Ingenieria, Universidad de Los Andes, La Hechicera, Merida 5101 (Venezuela); Bordons, Carlos; Camacho, Eduardo F. [Departamento de Ingenieria de Sistemas y Automatica, Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de Los Descubrimientos s/n, Sevilla 41092 (Spain)

    2008-03-15

    This paper describes the dynamic model of a solar cooling plant that has been built for demonstration purposes using market-available technology and has been successfully operational since 2001. The plant uses hot water coming from a field of solar flat collectors which feed a single-effect absorption chiller of 35 kW nominal cooling capacity. The work includes model development based on first principles and model validation with a set of experiments carried out on the real plant. The simulation model has been done in a modular way, and can be adapted to other solar cooling-plants since the main modules (solar field, absorption machine, accumulators and auxiliary heater) can be easily replaced. This simulator is a powerful tool for solar cooling systems both during the design phase, when it can be used for component selection, and also for the development and testing of control strategies. (author)

  10. SPECIAL SEMINAR - The NOTTE experiment, or how to become a Total Solar Eclipse chaser

    CERN Document Server

    CERN. Geneva

    2007-01-01

    The seminar will be followed by a brief presentation of future camps for solar eclipse chasers and scientists organized in 2008 in Russia, Kazakhstan, China and Mongolia, in 2009 in Shanghai and on the Easter Island in 2010.

  11. Empirical models of Total Electron Content based on functional fitting over Taiwan during geomagnetic quiet condition

    Directory of Open Access Journals (Sweden)

    Y. Kakinami

    2009-08-01

    Full Text Available Empirical models of Total Electron Content (TEC based on functional fitting over Taiwan (120° E, 24° N have been constructed using data of the Global Positioning System (GPS from 1998 to 2007 during geomagnetically quiet condition (Dst>−30 nT. The models provide TEC as functions of local time (LT, day of year (DOY and the solar activity (F, which are represented by 1–162 days mean of F10.7 and EUV. Other models based on median values have been also constructed and compared with the models based on the functional fitting. Under same values of F parameter, the models based on the functional fitting show better accuracy than those based on the median values in all cases. The functional fitting model using daily EUV is the most accurate with 9.2 TECu of root mean square error (RMS than the 15-days running median with 10.4 TECu RMS and the model of International Reference Ionosphere 2007 (IRI2007 with 14.7 TECu RMS. IRI2007 overestimates TEC when the solar activity is low, and underestimates TEC when the solar activity is high. Though average of 81 days centered running mean of F10.7 and daily F10.7 is often used as indicator of EUV, our result suggests that average of F10.7 mean from 1 to 54 day prior and current day is better than the average of 81 days centered running mean for reproduction of TEC. This paper is for the first time comparing the median based model with the functional fitting model. Results indicate the functional fitting model yielding a better performance than the median based one. Meanwhile we find that the EUV radiation is essential to derive an optimal TEC.

  12. Models of Labour Services and Estimates of Total Factor Productivity

    OpenAIRE

    Robert Dixon; David Shepherd

    2007-01-01

    This paper examines the manner in which labour services are modelled in the aggregate production function, concentrating on the relationship between numbers employed and average hours worked. It argues that numbers employed and hours worked are not perfect substitutes and that conventional estimates of total factor productivity which, by using total hours worked as the measure of labour services, assume they are perfect substitutes, will be biased when there are marked changes in average hour...

  13. Verification of high-speed solar wind stream forecasts using operational solar wind models

    CERN Document Server

    Reiss, Martin A; Veronig, Astrid M; Nikolic, Ljubomir; Vennerstrom, Susanne; Schoengassner, Florian; Hofmeister, Stefan J

    2016-01-01

    High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate high-speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang-Sheeley-Arge (WSA) model based on the in situ plasma measurements from the ACE spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation between the coronal hole area observed in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images and solar wind properties at the near-Earth environment, the WSA model establishes a link between properties of the open magnetic field lines extending from the photosphere to the corona and the background solar wind conditions. We found that both solar wind models are capable of predicting the large-scale features of the observed sol...

  14. Potential of Solar Energy in Kota Kinabalu, Sabah: An Estimate Using a Photovoltaic System Model

    Science.gov (United States)

    Markos, F. M.; Sentian, J.

    2016-04-01

    Solar energy is becoming popular as an alternative renewable energy to conventional energy source, particularly in the tropics, where duration and intensity of solar radiation are longer. This study is to assess the potential of solar energy generated from solar for Kota Kinabalu, a rapidly developing city in the State of Sabah, Malaysia. A year data of solar radiation was obtained using pyranometer, which was located at Universiti Malaysia Sabah (6.0367° N, 116.1186° E). It was concluded that the annual average solar radiation received in Kota Kinabalu was 182 W/m2. In estimating the potential energy generated from solar for Kota Kinabalu city area, a photovoltaic (PV) system model was used. The results showed that, Kota Kinabalu is estimated to produce 29,794 kWh/m2 of electricity from the solar radiation received in a year. This is equivalent to 0.014 MW of electricity produced just by using one solar panel. Considering the power demand in Sabah by 2020 is 1,331 MW, this model showed that the solar energy can contribute around 4% of energy for power demand, with 1 MW capacity of the PV system. 1 MW of PV system installation will require about 0.0328% from total area of the city. This assessment could suggest that, exploration for solar power energy as an alternative source of renewable energy in the city can be optimised and designed to attain significant higher percentage of contribution to the energy demand in the state.

  15. Life course models: improving interpretation by consideration of total effects.

    Science.gov (United States)

    Green, Michael J; Popham, Frank

    2016-12-28

    Life course epidemiology has used models of accumulation and critical or sensitive periods to examine the importance of exposure timing in disease aetiology. These models are usually used to describe the direct effects of exposures over the life course. In comparison with consideration of direct effects only, we show how consideration of total effects improves interpretation of these models, giving clearer notions of when it will be most effective to intervene. We show how life course variation in the total effects depends on the magnitude of the direct effects and the stability of the exposure. We discuss interpretation in terms of total, direct and indirect effects and highlight the causal assumptions required for conclusions as to the most effective timing of interventions.

  16. Modeling solar radiation at the Earth's surface recent advances

    CERN Document Server

    Badescu, Viorel

    2008-01-01

    Solar radiation data is important for a wide range of applications, e.g. in engineering, agriculture, health sector, and in many fields of the natural sciences. A few examples showing the diversity of applications may include: architecture and building design e.g. air conditioning and cooling systems; solar heating system design and use; solar power generation; weather and climate prediction models; evaporation and irrigation; calculation of water requirements for crops; monitoring plant growth and disease control; skin cancer research. Solar radiation data must be provided in a variety of f

  17. Magneto-Vortex Dynamo Model in Solar convection zone

    CERN Document Server

    Ershkov, Sergey V

    2011-01-01

    Here is presented a new magneto-vortex dynamo model for modeling & predicting of a processes in Solar plasma convection zone. Solar convection zone is located above the level r > 0,6-0,7 R, where R is a Solar radius. A key feature of such a model is that equation of Solar plasma motion as well as equation of magnetic fields evolution - are reduced to Helmholtz's vortex equation, which is up-graded in according with alpha-effect (Coriolis force forms an additional vorticity field or magnetic field due to Sun's differential rotation). Such an additional vorticity or magnetic field are proved to be concentrated at the proper belt in Solar convection zone under the influence of Coriolis force (at the middle latitudes of the Sun in respect to equator). Besides, such an an additional vorticity & magnetic fields are to be the basic sources of well-known phenomena "Maunder's butterfly" diagram.

  18. DETAILED MODELLING OF CHARGING BEHAVIOUR OF SMART SOLAR TANKS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Andersen, Elsa; Furbo, Simon

    2010-01-01

    The charging behaviour of smart solar tanks for solar combisystems for one-family houses is investigated with detailed Computational Fluid Dynamics (CFD) modelling and Particle Image Velocimetry (PIV) measurements. The smart solar tank can be charged with a variable auxiliary volume fitted...... to the expected future energy demand. Therefore the heat loss from the tank is decreased and the thermal performance of the solar heating system is increased compared to a traditional system with a fixed auxiliary volume. The solar tank can be charged either by an electric heating element situated in the tank...... or by an electric heating element in a side-arm mounted on the side of the tank. Detailed CFD models of the smart tanks are built with different mesh densities in the tank and in the side-arm. The thermal conditions of the tank during charging are calculated with the CFD models. The fluid flow and temperature...

  19. DETAILED MODELLING OF CHARGING BEHAVIOUR OF SMART SOLAR TANKS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Andersen, Elsa; Furbo, Simon

    The charging behaviour of smart solar tanks for solar combisystems for one-family houses is investigated with detailed Computational Fluid Dynamics (CFD) modelling and Particle Image Velocimetry (PIV) measurements. The smart solar tank can be charged with a variable auxiliary volume fitted...... to the expected future energy demand. Therefore the heat loss from the tank is decreased and the thermal performance of the solar heating system is increased compared to a traditional system with a fixed auxiliary volume. The solar tank can be charged either by an electric heating element situated in the tank...... or by an electric heating element in a side-arm mounted on the side of the tank. Detailed CFD models of the smart tanks are built with different mesh densities in the tank and in the side-arm. The thermal conditions of the tank during charging are calculated with the CFD models. The fluid flow and temperature...

  20. Collaborative problem solving with a total quality model.

    Science.gov (United States)

    Volden, C M; Monnig, R

    1993-01-01

    A collaborative problem-solving system committed to the interests of those involved complies with the teachings of the total quality management movement in health care. Deming espoused that any quality system must become an integral part of routine activities. A process that is used consistently in dealing with problems, issues, or conflicts provides a mechanism for accomplishing total quality improvement. The collaborative problem-solving process described here results in quality decision-making. This model incorporates Ishikawa's cause-and-effect (fishbone) diagram, Moore's key causes of conflict, and the steps of the University of North Dakota Conflict Resolution Center's collaborative problem solving model.

  1. Solar Deployment System (SolarDS) Model: Documentation and Sample Results

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, P.; Drury, E.; Margolis, R.

    2009-09-01

    The Solar Deployment System (SolarDS) model is a bottom-up, market penetration model that simulates the potential adoption of photovoltaics (PV) on residential and commercial rooftops in the continental United States through 2030. NREL developed SolarDS to examine the market competitiveness of PV based on regional solar resources, capital costs, electricity prices, utility rate structures, and federal and local incentives. The model uses the projected financial performance of PV systems to simulate PV adoption for building types and regions then aggregates adoption to state and national levels. The main components of SolarDS include a PV performance simulator, a PV annual revenue calculator, a PV financial performance calculator, a PV market share calculator, and a regional aggregator. The model simulates a variety of installed PV capacity for a range of user-specified input parameters. PV market penetration levels from 15 to 193 GW by 2030 were simulated in preliminary model runs. SolarDS results are primarily driven by three model assumptions: (1) future PV cost reductions, (2) the maximum PV market share assumed for systems with given financial performance, and (3) PV financing parameters and policy-driven assumptions, such as the possible future cost of carbon emissions.

  2. Helicity of Solar Active Regions from a Dynamo Model

    Indian Academy of Sciences (India)

    Piyali Chatterjee

    2006-06-01

    We calculate helicities of solar active regions based on the idea that poloidal flux lines get wrapped around a toroidal flux tube rising through the convection zone, thereby giving rise to the helicity. We use our solar dynamo model based on the Babcock–Leighton -effect to study how helicity varies with latitude and time.

  3. Magnetosonic Waveguide Model of Solar Wind Flow Tubes

    Indian Academy of Sciences (India)

    A. K. Srivastava; B. N. Dwivedi

    2006-06-01

    We consider solar wind flow tubes as a magnetosonic wave-guide. Assuming a symmetric expansion in edges of slab-modelled wave-guide, we study the propagation characteristics of magnetosonic wave in the solar wind flow tubes. We present the preliminary results and discuss their implications.

  4. Zenith sky brightness and celestial objects visibility during total solar eclipse on March 9, 2016 at Terentang Beach Bangka Island

    Science.gov (United States)

    Wijaya, A. F. C.; Asmoro, C. P.; Rochman, A. A.; Ramalis, T. R.; Utama, J. A.; Ardi, N. D.; Amsor; Nugraha, M. G.; Saepuzaman, D.; Sutiadi, A.; Nurfiani, D.

    2016-11-01

    This paper endeavor to describe sky brightness measurements which was carried out by a team of total solar eclipse observers (TOGEMA) on 9th March 2016. The observations took place at Tarentang Beach, Bangka Island and it utilized the SQM-LU instrument (Sky Quality Meter- USB Connector) with 1 second time interval data. During total phase that lasted about 1 minute 52 seconds, the instrument recorded the brightness of the sky of 12.88 mag/["]2 as the dimmest value. This value is approximately 500 times brighter than the dimmest night sky conditions at the same location, obtained on the previous observation. It was found that the brightest sky that could be measured by SQM-LU during Total Solar Eclipse (TSE) 2016 was 5.91 mag/["]2. The activity with digital camera also captured the appearance of Venus and Mercury. The appearance of Venus (-3.71 mag) confirmed naked eye limited magnitude theory. This may explain the inability of observers to perceive Mercury (0.46 mag) using naked eye during the total phase of solar eclipse.

  5. Measurement of the nue and Total 8B Solar Neutrino Fluxes with theSudbury Neutrino Observatory Phase I Data Set

    Energy Technology Data Exchange (ETDEWEB)

    Aharmim, B.; Ahmad, Q.R.; Ahmed, S.N.; Allen, R.C.; Andersen,T.C.; Anglin, J.D.; Buehler, G.; Barton, J.C.; Beier, E.W.; Bercovitch,M.; Bergevin, M.; Bigu, J.; Biller, S.D.; Black, R.A.; Blevis, I.; Boardman, R.J.; Boger, J.; Bonvin, E.; Boulay, M.G.; Bowler, M.G.; Bowles, T.J.; Brice, S.J.; Browne, M.C.; Bullard, T.V.; Burritt, T.H.; Cameron, J.; Chan, Y.D.; Chen, H.H.; Chen, M.; Chen, X.; Cleveland, B.T.; Cowan, J.H.M.; Cowen, D.F.; Cox, G.A.; Currat, C.A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W.F.; Deng, H.; DiMarco, M.; Doe, P.J.; Doucas, G.; Dragowsky, M.R.; Duba, C.A.; Duncan, F.A.; Dunford, M.; Dunmore, J.A.; Earle, E.D.; Elliott, S.R.; Evans, H.C.; Ewan, G.T.; Farine, J.; Fergani, H.; Ferraris, A.P.; Fleurot, F.; Ford, R.J.; Formaggio, J.A.; Fowler, M.M.; Frame, K.; Frank, E.D.; Frati, W.; Gagnon,N.; Germani, J.V.; Gil, S.; Goldschmidt, A.; Goon, J.T.M.; Graham, K.; Grant, D.R.; Guillian, E.; Hahn, R.L.; Hallin, A.L.; Hallman, E.D.; Hamer, A.S.; Hamian, A.A.; Handler, W.B.; Haq, R.U.; Hargrove, C.K.; Harvey, P.J.; Hazama, R.; Heeger, K.M.; Heintzelman, W.J.; Heise, J.; Helmer, R.L.; Henning, R.; Hepburn, J.D.; Heron, H.; Hewett, J.; Hime,A.; Howard, C.; Howe, M.A.; Huang, M.; Hykawy, J.G.; Isaac, M.C.P.; Jagam, P.; Jamieson, B.; Jelley, N.A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P.T.; Kirch, K.; Klein, J.R.; Knox, A.B.; Komar,R.J.; Kormos, L.L.; Kos, M.; Kouzes, R.; Krueger, A.; Kraus, C.; Krauss,C.B.; Kutter, T.; Kyba, C.C.M.; Labranche, H.; Lange, R.; Law, J.; Lawson, I.T.; Lay, M.; Lee, H.W.; Lesko, K.T.; Leslie, J.R.; Levine, I.; Loach, J.C.; Locke, W.; Luoma, S.; Lyon, J.; MacLellan, R.; Majerus, S.; Mak, H.B.; Maneira, J.; Marino, A.D.; Martin, R.; McCauley, N.; McDonald,A.B.; McDonald, D.S.; McFarlane, K.; McGee, S.; McGregor, G.; MeijerDrees, R.; Mes, H.; Mifflin, C.; Miknaitis, K.K.S.; Miller, M.L.; Milton,G.; Moffat, B.A.; Monreal, B.; Moorhead, M.; Morrissette, B.; Nally,C.W.; Neubauer, M.S.; et al.

    2007-02-01

    This article provides the complete description of resultsfrom the Phase I data set of the Sudbury Neutrino Observatory (SNO). ThePhase I data set is based on a 0.65 kt-year exposure of heavy water tothe solar 8B neutrino flux. Included here are details of the SNO physicsand detector model, evaluations of systematic uncertainties, andestimates of backgrounds. Also discussed are SNO's approach tostatistical extraction of the signals from the three neutrino reactions(charged current, neutral current, and elastic scattering) and theresults of a search for a day-night asymmetry in the ?e flux. Under theassumption that the 8B spectrum is undistorted, the measurements fromthis phase yield a solar ?e flux of ?(?e) =1.76+0.05?0.05(stat.)+0.09?0.09 (syst.) x 106 cm?2 s?1, and a non-?ecomponent ?(? mu) = 3.41+0.45?0.45(stat.)+0.48?0.45 (syst.) x 106 cm?2s?1. The sum of these components provides a total flux in excellentagreement with the predictions of Standard Solar Models. The day-nightasymmetry in the ?e flux is found to be Ae = 7.0 +- 4.9 (stat.)+1.3?1.2percent (sys.), when the asymmetry in the total flux is constrained to bezero.

  6. Dynamic model of heat and mass transfer in rectangular adsorber of a solar adsorption machine

    Science.gov (United States)

    Chekirou, W.; Boukheit, N.; Karaali, A.

    2016-10-01

    This paper presents the study of a rectangular adsorber of solar adsorption cooling machine. The modeling and the analysis of the adsorber are the key point of such studies; because of the complex coupled heat and mass transfer phenomena that occur during the working cycle. The adsorber is heated by solar energy and contains a porous medium constituted of activated carbon AC-35 reacting by adsorption with methanol. To study the solar collector type effect on system's performances, the used model takes into account the variation of ambient temperature and solar intensity along a simulated day, corresponding to a total daily insolation of 26.12 MJ/m2 with ambient temperature average of 27.7 °C, which is useful to know the daily thermal behavior of the rectangular adsorber.

  7. Planar solar concentrator featuring alignment-free total-internal-reflection collectors and an innovative compound tracker.

    Science.gov (United States)

    Teng, Tun-Chien; Lai, Wei-Che

    2014-12-15

    This study proposed a planar solar concentrator featuring alignment-free total-internal-reflection (TIR) collectors and an innovative compound tracker. The compound tracker, combining a mechanical single-axis tracker and scrollable prism sheets, can achieve a performance on a par with dual-axis tracking while reducing the cost of the tracking system and increasing its robustness. The alignment-free TIR collectors are assembled on the waveguide without requiring alignment, so the planar concentrator is relatively easily manufactured and markedly increases the feasibility for use in large concentrators. Further, the identical TIR collector is applicable to various-sized waveguide slab without requiring modification, which facilitates flexibility regarding the size of the waveguide slab. In the simulation model, the thickness of the slab was 2 mm, and its maximal length reached 6 m. With an average angular tolerance of ±0.6°, and after considering both the Fresnel loss and the angular spread of the sun, the simulation indicates that the waveguide concentrator of a 1000-mm length provides the optical efficiencies of 62-77% at the irradiance concentrations of 387-688, and the one of a 2000-mm length provides the optical efficiencies of 52-64.5% at the irradiance concentrations of 645-1148. Alternatively, if a 100-mm horizontally staggered waveguide slab is collocated with the alignment-free TIR collectors, the optical efficiency would be greatly improved up to 91.5% at an irradiance concentration of 1098 (C(geo) = 1200X).

  8. Image Denoising Using Total Variation Model Guided by Steerable Filter

    Directory of Open Access Journals (Sweden)

    Wenxue Zhang

    2014-01-01

    Full Text Available We propose an adaptive total variation (TV model by introducing the steerable filter into the TV-based diffusion process for image filtering. The local energy measured by the steerable filter can effectively characterize the object edges and ramp regions and guide the TV-based diffusion process so that the new model behaves like the TV model at edges and leads to linear diffusion in flat and ramp regions. This way, the proposed model can provide a better image processing tool which enables noise removal, edge-preserving, and staircase suppression.

  9. On forecasting ionospheric total electron content responses to high-speed solar wind streams

    Directory of Open Access Journals (Sweden)

    Meng Xing

    2016-01-01

    Full Text Available Conditions in the ionosphere have become increasingly important to forecast, since more and more spaceborne and ground-based technological systems rely on ionospheric weather. Here we explore the feasibility of ionospheric forecasts with the current generation of physics-based models. In particular, we focus on total electron content (TEC predictions using the Global Ionosphere-Thermosphere Model (GITM. Simulations are configured in a forecast mode and performed for four typical high-speed-stream events during 2007–2012. The simulated TECs are quantified through a metric, which divides the globe into a number of local regions and robustly differentiates between quiet and disturbed periods. Proposed forecast products are hourly global maps color-coded by the TEC disturbance level of each local region. To assess the forecasts, we compare the simulated TEC disturbances with global TEC maps derived from Global Positioning System (GPS satellite observations. The forecast performance is found to be merely acceptable, with a large number of regions where the observed variations are not captured by the simulations. Examples of model-data agreements and disagreements are investigated in detail, aiming to understand the model behavior and improve future forecasts. For one event, we identify two adjacent regions with similar TEC observations but significant differences in how local chemistry versus plasma transport contribute to electron density changes in the simulation. Suggestions for further analysis are described.

  10. On forecasting ionospheric total electron content responses to high-speed solar wind streams

    Science.gov (United States)

    Meng, Xing; Mannucci, Anthony J.; Verkhoglyadova, Olga P.; Tsurutani, Bruce T.

    2016-04-01

    Conditions in the ionosphere have become increasingly important to forecast, since more and more spaceborne and ground-based technological systems rely on ionospheric weather. Here we explore the feasibility of ionospheric forecasts with the current generation of physics-based models. In particular, we focus on total electron content (TEC) predictions using the Global Ionosphere-Thermosphere Model (GITM). Simulations are configured in a forecast mode and performed for four typical high-speed-stream events during 2007-2012. The simulated TECs are quantified through a metric, which divides the globe into a number of local regions and robustly differentiates between quiet and disturbed periods. Proposed forecast products are hourly global maps color-coded by the TEC disturbance level of each local region. To assess the forecasts, we compare the simulated TEC disturbances with global TEC maps derived from Global Positioning System (GPS) satellite observations. The forecast performance is found to be merely acceptable, with a large number of regions where the observed variations are not captured by the simulations. Examples of model-data agreements and disagreements are investigated in detail, aiming to understand the model behavior and improve future forecasts. For one event, we identify two adjacent regions with similar TEC observations but significant differences in how local chemistry versus plasma transport contribute to electron density changes in the simulation. Suggestions for further analysis are described.

  11. A Total Generalized Optimal Velocity Model and Its Numerical Tests

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen-xing; LIU Yun-cai

    2008-01-01

    A car-following model named total generalized optimal velocity model (TGOVM) was developed with a consideration of an arbitrary number of preceding vehicles before current one based on analyzing the previous models such as optimal velocity model (OVM), generalized OVM (GOVM) and improved GOVM (IGOVM). This model describes the physical phenomena of traffic flow more exactly and realistically than previous models. Also the performance of this model was checked out by simulating the acceleration and de- celeration process for a small delay time. On a single circular lane, the evolution of the traffic congestion was studied for a different number of headways and relative velocities of the preceding vehicles being taken into account. The simulation results show that TGOVM is reasonable and correct.

  12. Ionospheric Response to the Total Solar Eclipse of 22 July 2009 as Deduced from VLBI and GPS Data

    Science.gov (United States)

    Guo, L.; Shu, F. C.; Zheng, W. M.; Kondo, T.; Ichikawa, R.; Hasegawa, S.; Sekido, M.

    2010-01-01

    A total solar eclipse occurred over China at latitudes of about 30 N on the morning of 22 July 2009, providing a unique opportunity to investigate the influence of the sun on the earth's upper ionosphere. GPS observations from Shanghai GPS Local Network and VLBI observations from stations Shanghai, Urumqi, and Kashima were used to observe the response of TEC to the total solar eclipse. From the GPS data reduction, the sudden decrease of TEC at the time of the eclipse, amounting to 2.8 TECU, and gradual increase of TEC after the eclipse were found by analyzing the diurnal variations. More distinctly, the variations of TEC were studied along individual satellite passes. The delay in reaching the minimum level of TEC with the maximum phase of eclipse was 5-10 min. Besides, we also compared the ionospheric activity derived from different VLBI stations with the GPS results and found a strong correlation between them.

  13. Total Quality Management, a New Culture Model of the Enterprise

    Directory of Open Access Journals (Sweden)

    Constantin Dumitrescu

    2006-10-01

    Full Text Available The paper brings bags of clarifications about concept definition and bases principles of TQM, presenting the critical factors during the implementation of those fundamentals. Also, it has been proposed a lot of models to present the Total Quality Management, being also presented its evolution.

  14. 3D electron density distributions in the solar corona during solar minima: assessment for more realistic solar wind modeling

    CERN Document Server

    de Patoul, Judith; Riley, Pete

    2015-01-01

    Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996-1997 and 2008-2010), devoid of coronal mass ejections. The goals are to derive the 4D electron density distributions in the corona by applying a newly developed time-dependent tomographic reconstruction method and to compare the results between the two solar minima and with two magnetohydrodynamic models. First, we confirm that the values of the density distribution in thermodynamic models are more realistic than in polytropic ones. The tomography provides more accurate distributions in the polar regions, and we find that the density in tomographic and thermodynamic solutions varies with the solar cycle in both polar and equatorial regions. Second, we find that the highest-density structures do not always correspond to the...

  15. Mathematical modelling of unglazed solar collectors under extreme operating conditions

    DEFF Research Database (Denmark)

    Bunea, M.; Perers, Bengt; Eicher, S.

    2015-01-01

    average temperature levels at the evaporator. Simulation of these systems requires a collector model that can take into account operation at very low temperatures (below freezing) and under various weather conditions, particularly operation without solar irradiation.A solar collector mathematical model......Combined heat pumps and solar collectors got a renewed interest on the heating system market worldwide. Connected to the heat pump evaporator, unglazed solar collectors can considerably increase their efficiency, but they also raise the coefficient of performance of the heat pump with higher...... was found due to the condensation phenomenon and up to 40% due to frost under no solar irradiation. This work also points out the influence of the operating conditions on the collector's characteristics.Based on experiments carried out at a test facility, every heat flux on the absorber was separately...

  16. Obtaining Electron Temperatures and Flow Speeds from Thomson Scattered Coronal Emission Observed during the 29 March 2006 Total Solar Eclipse in Libya

    Science.gov (United States)

    Davila, Joseph M.; Geginald, Nelson L.; Gashut, Hadi; Guhathakurta, Madhulika; Hassler, Donald M.

    2008-01-01

    An experiment to measure the electron temperature and flow speed in the solar corona by observing the visible K-coronal spectrum was conducted during the total solar eclipse on 29 March 2006 in Libya. New corona1 models accounting for the effect of electron temperature and flow on the resulting K-corona spectrum were used to interpret the observations. Results show electron temperatures of 1.10 +/- 0.05, 0.98 +/- 0.12, and 0.70 +/- 0.08 MK, at l.l{\\it R)$-{\\odot)$ in the solar north, east and west, respectively, and 0.93 +/- 0.12 MK, at 1.2 R(sub sun) in the solar east. The corresponding outflow speeds obtained from the spectral fit are 103 +/- 92, 0 + 10, 0 + 10, and 0 + 10 km/s. Since the observations are taken only at 1.1 and 1.2 R(sub sun) these velocities , consistent with zero outflow, are in agreement with expectations and provide additional confirmation that the spectral fitting method is working.

  17. Obtaining Electron Temperatures and Flow Speeds from Thomson Scattered Coronal Emission Observed during the 29 March 2006 Total Solar Eclipse in Libya

    Science.gov (United States)

    Davila, Joseph M.; Geginald, Nelson L.; Gashut, Hadi; Guhathakurta, Madhulika; Hassler, Donald M.

    2008-01-01

    An experiment to measure the electron temperature and flow speed in the solar corona by observing the visible K-coronal spectrum was conducted during the total solar eclipse on 29 March 2006 in Libya. New corona1 models accounting for the effect of electron temperature and flow on the resulting K-corona spectrum were used to interpret the observations. Results show electron temperatures of 1.10 +/- 0.05, 0.98 +/- 0.12, and 0.70 +/- 0.08 MK, at l.l{\\it R)$-{\\odot)$ in the solar north, east and west, respectively, and 0.93 +/- 0.12 MK, at 1.2 R(sub sun) in the solar east. The corresponding outflow speeds obtained from the spectral fit are 103 +/- 92, 0 + 10, 0 + 10, and 0 + 10 km/s. Since the observations are taken only at 1.1 and 1.2 R(sub sun) these velocities , consistent with zero outflow, are in agreement with expectations and provide additional confirmation that the spectral fitting method is working.

  18. Comparative Study of MHD Modeling of the Background Solar Wind

    CERN Document Server

    Gressl, C; Temmer, M; Odstrcil, D; Linker, J A; Mikic, Z; Riley, P

    2013-01-01

    Knowledge about the background solar wind plays a crucial role in the framework of space weather forecasting. In-situ measurements of the background solar wind are only available for a few points in the heliosphere where spacecraft are located, therefore we have to rely on heliospheric models to derive the distribution of solar wind parameters in interplanetary space. We test the performance of different solar wind models, namely Magnetohydrodynamic Algorithm outside a Sphere/ENLIL (MAS/ENLIL), Wang-Sheeley-Arge/ENLIL (WSA/ENLIL), and MAS/MAS, by comparing model results with in-situ measurements from spacecraft located at 1 AU distance to the Sun (ACE, Wind). To exclude the influence of interplanetary coronal mass ejections (ICMEs), we chose the year 2007 as a time period with low solar activity for our comparison. We found that the general structure of the background solar wind is well reproduced by all models. The best model results were obtained for the parameter solar wind speed. However, the predicted ar...

  19. Performance of the meteorological radiation model during the solar eclipse of 29 March 2006

    Directory of Open Access Journals (Sweden)

    B. E. Psiloglou

    2007-08-01

    Full Text Available Various solar broadband models have been developed in the last half of the 20th century. The driving demand has been the estimation of available solar energy at different locations on earth for various applications. The motivation for such developments, though, has been the ample lack of solar radiation measurements at global scale. Therefore, the main goal of such codes was to generate artificial solar radiation series or calculate the availability of solar energy at a place.

    One of the broadband models to be developed in the late 80's was the Meteorological Radiation Model (MRM. The main advantage of MRM over other similar models was its simplicity in acquiring and using the necessary input data, i.e., air temperature, relative humidity, barometric pressure and sunshine duration from any of the many meteorological stations.

    The present study describes briefly the various steps (versions of MRM and in greater detail the latest version 5. To show the flexibility and great performance of the MRM, a harsh test of the code under the (almost total solar eclipse conditions of 29 March 2006 over Athens was performed and comparison of its results with real measurements was made. From this hard comparison it is shown that the MRM can simulate solar radiation during a solar eclipse event as effectively as on a typical day. The value of this comparison is further enhanced if it said that the sky was cloudy almost all the duration of the solar eclipse event.

  20. Terrestrial atmospheric responses on Svalbard to the 20 March 2015 Arctic total solar eclipse under extreme conditions.

    Science.gov (United States)

    Pasachoff, J M; Peñaloza-Murillo, M A; Carter, A L; Roman, M T

    2016-09-28

    This article reports on the near-surface atmospheric response at the High Arctic site of Svalbard, latitude 78° N, as a result of abrupt changes in solar insolation during the 20 March 2015 equinox total solar eclipse and notifies the atmospheric science community of the availability of a rare dataset. Svalbard was central in the path of totality, and had completely clear skies. Measurements of shaded air temperature and atmospheric pressure show only weak, if any, responses to the reduced insolation. A minimum in the air temperature at 1.5 m above the ground occurred starting 2 min following the end of totality, though this drop was only slightly beyond the observed variability for the midday period. Eclipse-produced variations in surface pressure, if present, were less than 0.3 hPa.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.

  1. CFD modeling of pulsatile hemodynamics in the total cavopulmonary connection

    Science.gov (United States)

    Zobaer, S. M. Tareq; Hasan, A. B. M. Toufique

    2016-07-01

    Total cavopulmonary connection is a blood flow pathway which is created surgically by an operation known as Fontan procedure, performed on children with single ventricle heart defects. Recent studies have shown that the hemodynamics in the connection can be strongly influenced by the presence of pulsatile flow. The aim of this paper is model the pulsatile flow patterns, and to calculate the vorticity field and power losses in an idealized 1.5D offset model of Total Cavopulmonary Connection. A three-dimensional polyhedral mesh was constructed for the numerical simulation. The rheological properties of blood were considered as Newtonian, and flow in the connection was assumed to be laminar. The results demonstrated complex flow patterns in the connection. The outcomes of the simulation showed reasonable agreement with the results available in the literature for a similar model.

  2. Kinematic solar dynamo models with a deep meridional flow

    Science.gov (United States)

    Guerrero, G. A.; Muñoz, J. D.

    2004-05-01

    We develop two different solar dynamo models to verify the hypothesis that a deep meridional flow can restrict the appearance of sunspots below 45°, proposed recently by Nandy & Choudhuri. In the first one, a single polytropic approximation for the density profile was taken, for both radiative and convective zones. In the second one, that of Pinzon & Calvo-Mozo, two polytropes were used to distinguish between both zones. The magnetic buoyancy mechanism proposed by Dikpati & Charbonneau was chosen in both models. We have in fact obtained that a deep meridional flow pushes the maxima of toroidal magnetic field towards the solar equator, but, in contrast to Nandy & Choudhuri, a second zone of maximal fields remains at the poles. The second model, although closely resembling the solar standard model of Bahcall et al., gives solar cycles three times longer than observed.

  3. Kinematic solar dynamo models with a deep meridional flow

    CERN Document Server

    Guerrero, G A

    2004-01-01

    We develop two different solar dynamo models to verify the hypothesis that a deep meridional flow can restrict the apperance of sunspots below 45 degrees, proposed by Nandy & Choudhuri (2002). In the first one, a single polytropic approximation for the density profile was taken, for both radiative and convective zones. In the second one, two polytropes were used to distinguish between both zones Pinzon & Calvo-Mozo (2001). The magnetic buoyancy mechanism proposed by Dikpati & Charbonneau (1999) was chosen in both models. We, actually, have obtained that a deep meridional flow pushes the maxima of toroidal magnetic field toward the solar equator, but in contrast to Nandy & Choudhuri (2002) a second zone of maximal fields remains at the poles. The second model, although closely resembling the solar standard model of Bahcall, Pinsonneault & Wasserbug (1995); Bahcall, Pinsonneault & Basu (2001), gives solar cyles three times longer than observed.

  4. Mathematical Modeling of Dual Intake Transparent Transpired Solar Collector

    Directory of Open Access Journals (Sweden)

    Thomas Semenou

    2015-01-01

    Full Text Available Nowadays, in several types of commercial or institutional buildings, a significant rise of transpired solar collectors used to preheat the fresh air of the building can be observed. Nevertheless, when the air mass flow rate is low, the collector efficiency collapses and a large amount of energy remains unused. This paper presents a simple yet effective mathematical model of a transparent transpired solar collector (TTC with dual intake in order to remove stagnation problems in the plenum and ensure a better thermal efficiency and more heat recovery. A thermal model and a pressure loss model were developed. Then, the combined model was validated with experimental data from the Solar Rating and Certification Corporation (SRCC. The results show that the collector efficiency can be up to 70% and even 80% regardless of operating conditions. The temperature gain is able to reach 20°K when the solar irradiation is high.

  5. Modeling the heliospheric current sheet: Solar cycle variations

    Science.gov (United States)

    Riley, Pete; Linker, J. A.; Mikić, Z.

    2002-07-01

    In this report we employ an empirically driven, three-dimensional MHD model to explore the evolution of the heliospheric current sheet (HCS) during the course of the solar cycle. We compare our results with a simpler ``constant-speed'' approach for mapping the HCS outward into the solar wind to demonstrate that dynamic effects can substantially deform the HCS in the inner heliosphere (ballerina skirt,'' we discuss an interval approaching the maximum of solar cycle 23 (Carrington rotations 1960 and 1961) when the shape would be better described as ``conch shell''-like. We use Ulysses magnetic field measurements to support the model results.

  6. Modeling Jets in the Corona and Solar Wind

    CERN Document Server

    Torok, T; Titov, V S; Leake, J E; Mikic, Z; Linker, J A; Linton, M G

    2015-01-01

    Coronal jets are transient, collimated eruptions that occur in regions of predominantly open magnetic field in the solar corona. Our understanding of these events has greatly evolved in recent years but several open questions, such as the contribution of coronal jets to the solar wind, remain. Here we present an overview of the observations and numerical modeling of coronal jets, followed by a brief description of "next-generation" simulations that include an advanced description of the energy transfer in the corona ("thermodynamic MHD"), large spherical computational domains, and the solar wind. These new models will allow us to address some of the open questions.

  7. Solar irradiance variability: A six-year comparison between SORCE observations and the SATIRE model

    CERN Document Server

    Ball, Will T; Krivova, Natalie A; Solanki, Sami; Harder, Jerald W

    2011-01-01

    Aims: We investigate how well modeled solar irradiances agree with measurements from the SORCE satellite, both for total solar irradiance and broken down into spectral regions on timescales of several years. Methods: We use the SATIRE model and compare modeled total solar irradiance (TSI) with TSI measurements between 2003 and 2009. Spectral solar irradiance over 200-1630nm is compared with the SIM instrument on SORCE between 2004 and 2009 during a period of decline from moderate activity to the recent solar minimum in 10 nm bands and for three spectral regions of significant interest: the UV integrated over 200-300nm, the visible over 400-691nm and the IR between 972-1630 nm. Results: The model captures 97% of observed TSI variation. In the spectral comparison, rotational variability is well reproduced, especially between 400 and 1200 nm. The magnitude of change in the long-term trends is many times larger in SIM at almost all wavelengths while trends in SIM oppose SATIRE in the visible between 500 and 700nm...

  8. A dissipative model of solar system

    Science.gov (United States)

    Vladimir, V. G.

    2009-04-01

    In classical model of Solar system of a planet are represented by the material points cooperating under the law of universal gravitation. This model remains fair if planet to consider as absolutely firm spheres with spherical distribution of density. The gravitational potential of such body coincides with potential of a material point, and rotation of each sphere concerning his centre of weights occurs to constant angular speed. Movement concerning the centre of weights of a sphere is represented by rotation with constant angular speed concerning an axis of an any direction, and movement of the centers of weights of spherical planets identically to movement in the appropriate problem of N points. Let's notice, that forms of planets of Solar system are close to spherical as dominant forces at formation of planets are gravitational forces to which forces of molecular interaction in substance of a planet counteract. The model of the isolated Solar system submitted in a not indignant condition N by homogeneous viscoelastic spheres is considered. Under action of own rotation and tidal gravitational forces the spherical planet changes the form: there is "flattening" a planet in a direction of a vector of its angular speed and formation of tidal humps on the lines connecting the centre of a planet with the centers of other planets. From a variational principle of Hamilton the full system of the equations describing movements of the centers of weights of planets, rotations of systems of coordinates, by integrated image connected with planets, and deformations of planets be relative these of systems of coordinates is received. It is supposed, that tidal gravitational, centrifugal and elastic forces result in small change of the spherical form of a planet. In system there are small parameters - inversely proportional of the Young modules of materials of the planets, providing small deformations of planets at influence on them of the centrifugal forces produced by own

  9. Combined photovoltaic/thermal solar array dc electrical model

    Energy Technology Data Exchange (ETDEWEB)

    Krikorian, J.S. Jr.

    1981-12-01

    An electrical model of a combined photovoltaic/thermal solar array has been developed to predict the steady state behavior of the line currents, power output and array voltage. The effects of temperature on the solar cell characteristics is included in the analysis. The model includes line isolation diodes and ''open cell'' bypass diodes. A numerical procedure based on the Contraction Mapping Fixed Point Theorem is used to solve the associated nonlinear equations. 6 refs.

  10. Availability modeling methodology applied to solar power systems

    Science.gov (United States)

    Unione, A.; Burns, E.; Husseiny, A.

    1981-01-01

    Availability is discussed as a measure for estimating the expected performance for solar- and wind-powered generation systems and for identifying causes of performance loss. Applicable analysis techniques, ranging from simple system models to probabilistic fault tree analysis, are reviewed. A methodology incorporating typical availability models is developed for estimating reliable plant capacity. Examples illustrating the impact of design and configurational differences on the expected capacity of a solar-thermal power plant with a fossil-fired backup unit are given.

  11. Investigation of the Effects of Solar and Geomagnetic Changes on the Total Electron Content: Mid-Latitude Region

    Science.gov (United States)

    Ulukavak, Mustafa; Yalcinkaya, Mualla

    2016-04-01

    The Global Positioning System (GPS) is used as an important tool for ionosphere monitoring and obtaining the Total Electron Content (TEC). GPS satellites, positioned in the Earth's orbit, are used as sensors to investigate the space weather conditions. In this study, solar and geomagnetic activity variations were investigated between the dates 1 March-30 June 2015 for the mid-latitude region. GPS-TEC variations were calculated for each selected International GNSS Service (IGS) station in Europe. GNSS data was obtained from Crustal Dynamics Data and Information System (CDDIS) archive. Solar and geomagnetic activity indices (Kp, F10.7 ve Dst) were obtained from the Oceanic and Atmospheric Administration (NOAA), the Canadian Space Weather Forecast Centre (CSWFC) and Data Analysis Center for geomagnetism and Space Magnetism Graduate School of Science, Kyoto University (WDC) archives. GPS-TEC variations were determined for the quiet periods of the solar and geomagnetic activities. GPS-TEC changes were then compared with respect to the quiet periods of the solar and geomagnetic activities. Global Ionosphere Maps (GIM) IONEX files, obtained from the IGS analysis center, was used to check the robustness of the GPS-TEC variations. The investigations revealed that it is possible to use the GPS-TEC data for monitoring the ionospheric disturbances.

  12. Modeling a radiotherapy clinical procedure: total body irradiation.

    Science.gov (United States)

    Esteban, Ernesto P; García, Camille; De La Rosa, Verónica

    2010-09-01

    Leukemia, non-Hodgkin's lymphoma, and neuroblastoma patients prior to bone marrow transplants may be subject to a clinical radiotherapy procedure called total body irradiation (TBI). To mimic a TBI procedure, we modified the Jones model of bone marrow radiation cell kinetics by adding mutant and cancerous cell compartments. The modified Jones model is mathematically described by a set of n + 4 differential equations, where n is the number of mutations before a normal cell becomes a cancerous cell. Assuming a standard TBI radiotherapy treatment with a total dose of 1320 cGy fractionated over four days, two cases were considered. In the first, repopulation and sub-lethal repair in the different cell populations were not taken into account (model I). In this case, the proposed modified Jones model could be solved in a closed form. In the second, repopulation and sub-lethal repair were considered, and thus, we found that the modified Jones model could only be solved numerically (model II). After a numerical and graphical analysis, we concluded that the expected results of TBI treatment can be mimicked using model I. Model II can also be used, provided the cancer repopulation factor is less than the normal cell repopulation factor. However, model I has fewer free parameters compared to model II. In either case, our results are in agreement that the standard dose fractionated over four days, with two irradiations each day, provides the needed conditioning treatment prior to bone marrow transplant. Partial support for this research was supplied by the NIH-RISE program, the LSAMP-Puerto Rico program, and the University of Puerto Rico-Humacao.

  13. On the Integration of Wind and Solar Energy to Provide a Total Energy Supply in the U.S

    Science.gov (United States)

    Liebig, E. C.; Rhoades, A.; Sloggy, M.; Mills, D.; Archer, C. L.

    2009-12-01

    This study examines the feasibility of using renewable energy - mostly wind and solar radiation - as the primary sources of energy in the U.S., under the assumption that a nationwide electric transmission grid is in place. Previous studies have shown that solar output from California and Texas using energy storage is well correlated with the state energy load on an hour by hour basis throughout the year and with the US national load on a monthly basis. Other studies have shown that solar or wind alone can power the present US grid on average. This study explores scenarios for use of wind and solar energy together at the national scale on an hour by hour basis to determine if such a combination is a better match to national seasonal load scenarios than either of the two alone on an hour-by-hour basis. Actual hour by hour national load data from a particular year will be used as a basis, with some scenarios incorporating vehicle sector electrification and building heating and cooling using electric heat pumps. Hydro and geothermal generation can provide additional controllable output, when needed, to fulfill the hourly electricity and/or energy needs. Hourly wind speed data were calculated at the hub height of 80 m above the ground for the year 2006 at over 150 windy locations in the continental US using an extrapolation technique based on 10-m wind speed measurements and vertical sounding profiles. Using a 1.5 MW wind turbine as benchmark, the hourly wind power production nationwide was determined at all locations. Similarly, the hourly output from solar plants, with and without thermal storage, was calculated based on Ausra’s model assuming that the solar production would occur in the Southwest, the area with the greatest solar radiation density in the U.S. Hourly electricity demand for the year 2006 was obtained nationwide from a variety of sources, including the Federal Energy Regulation Commission. Hourly residential heating and cooking, industrial heat

  14. Solar Desalination System Model for Sizing of Photovoltaic Reverse Osmosis (PVRO)

    KAUST Repository

    Habib, Abdulelah

    2015-06-28

    The focus of this paper is to optimize the solar energy utilization in the water desalination process. Due to variable nature of solar energy, new system design is needed to address this challenge. Here, reverse osmosis units, as the electrical loads, are considered as an ON/OFF units to track these solar energy variations. Reverse osmosis units are different in sizes and numbers. Various combinations of reverse osmosis units in size and capacity provide different water desalination system performances. To assess each scenario of reverse osmosis units, the total capital cost and operation and maintenance (O&M) cost are considered. The implemented optimization algorithm search all of the possible scenarios to find the best solution. This paper deploys the solar irradiance data which is provided from west coast (Red Sea) of Saudi Arabia for model construction and optimization algorithm implementation.

  15. Cost Effective System Modeling of Active Micro- Module Solar Tracker

    Directory of Open Access Journals (Sweden)

    Md. Faisal Shuvo

    2014-01-01

    Full Text Available The increasing interests in using renewable energies are coming from solar thermal energy and solar photovoltaic systems to the micro production of electricity. Usually we already have considered the solar tracking topology in large scale applications like power plants and satellite but most of small scale applications don’t have any solar tracker system, mainly because of its high cost and complex circuit design. From that aspect, this paper confab microcontroller based one dimensional active micro-module solar tracking system, in which inexpensive LDR is used to generate reference voltage to operate microcontroller for functioning the tracking system. This system provides a fast response of tracking system to the parameters like change of light intensity as well as temperature variations. This micro-module model of tracking system can be used for small scale applications like portable electronic devices and running vehicles.

  16. The MSFC Solar Activity Future Estimation (MSAFE) Model

    Science.gov (United States)

    Suggs, Ron

    2017-01-01

    The Natural Environments Branch of the Engineering Directorate at Marshall Space Flight Center (MSFC) provides solar cycle forecasts for NASA space flight programs and the aerospace community. These forecasts provide future statistical estimates of sunspot number, solar radio 10.7 cm flux (F10.7), and the geomagnetic planetary index, Ap, for input to various space environment models. For example, many thermosphere density computer models used in spacecraft operations, orbital lifetime analysis, and the planning of future spacecraft missions require as inputs the F10.7 and Ap. The solar forecast is updated each month by executing MSAFE using historical and the latest month's observed solar indices to provide estimates for the balance of the current solar cycle. The forecasted solar indices represent the 13-month smoothed values consisting of a best estimate value stated as a 50 percentile value along with approximate +/- 2 sigma values stated as 95 and 5 percentile statistical values. This presentation will give an overview of the MSAFE model and the forecast for the current solar cycle.

  17. Total Variability Modeling using Source-specific Priors

    DEFF Research Database (Denmark)

    Shepstone, Sven Ewan; Lee, Kong Aik; Li, Haizhou

    2016-01-01

    In total variability modeling, variable length speech utterances are mapped to fixed low-dimensional i-vectors. Central to computing the total variability matrix and i-vector extraction, is the computation of the posterior distribution for a latent variable conditioned on an observed feature...... sequence of an utterance. In both cases the prior for the latent variable is assumed to be non-informative, since for homogeneous datasets there is no gain in generality in using an informative prior. This work shows in the heterogeneous case, that using informative priors for com- puting the posterior......, can lead to favorable results. We focus on modeling the priors using minimum divergence criterion or fac- tor analysis techniques. Tests on the NIST 2008 and 2010 Speaker Recognition Evaluation (SRE) dataset show that our proposed method beats four baselines: For i-vector extraction using an already...

  18. Total cloud cover from satellite observations and climate models

    Directory of Open Access Journals (Sweden)

    P. Probst

    2010-09-01

    Full Text Available Global and zonal monthly means of cloud cover fraction for total cloudiness (CF from the ISCCP D2 dataset are compared to same quantity produced by the 20th century simulations of 21 climate models from the World Climate Research Programme's (WCRP's Coupled Model Intercomparison Project phase 3 (CMIP3 multi-model dataset archived by the Program for Climate Model Diagnosis and Intercomparison (PCMDI. The comparison spans the time frame from January 1984 to December 1999 and the global and zonal average of CF are studied. The restriction to total cloudiness depends on the output of some models that does not include the 3D cloud structure. It is shown that the global mean of CF for the PCMDI/CMIP3 models, averaged over the whole period, exhibits a considerable variance and generally underestimates the ISCCP value. Very large discrepancies among models, and between models and observations, are found in the polar areas, where both models and satellite observations are less reliable, and especially near Antarctica. For this reason the zonal analysis is focused over the 60° S–60° N latitudinal belt, which includes the tropical area and mid latitudes. The two hemispheres are analyzed separately to show the variation of the amplitude of the seasonal cycle. Most models overestimate the yearly averaged values of CF over all of the analysed areas, while differences emerge in their ability to capture the amplitude of the seasonal cycle. The models represent, in a qualitatively correct way, the magnitude and the weak sign of the seasonal cycle over the whole geographical domain, but overestimate the strength of the signal in the tropical areas and at mid-latitudes, when taken separately. The interannual variability of the two yearly averages and of the amplitude of the seasonal cycle is greatly underestimated by all models in each area analysed. This work shows that the climate models have an heterogeneous behaviour in simulating the CF over

  19. An Evaluation of Total Solar Reflectance and Spectral Band Ratioing Techniques for Estimating Soil Water Content

    Science.gov (United States)

    Reginato, R. J.; Vedder, J. F.; Idso, S. B.; Jackson, R. D.; Blanchard, M. B.; Goettelman, R.

    1977-01-01

    For several days in March of 1975, reflected solar radiation measurements were obtained from smooth and rough surfaces of wet, drying, and continually dry Avondale loam at Phoenix, Arizona, with pyranometers located 50 cm above the ground surface and a multispectral scanner flown at a 300-m height. The simple summation of the different band radiances measured by the multispectral scanner proved equally as good as the pyranometer data for estimating surface soil water content if the multispectral scanner data were standardized with respect to the intensity of incoming solar radiation or the reflected radiance from a reference surface, such as the continually dry soil. Without this means of standardization, multispectral scanner data are most useful in a spectral band ratioing context. Our results indicated that, for the bands used, no significant information on soil water content could be obtained by band ratioing. Thus the variability in soil water content should insignificantly affect soil-type discrimination based on identification of type-specific spectral signatures. Therefore remote sensing, conducted in the 0.4- to 1.0-micron wavelength region of the solar spectrum, would seem to be much More suited to identifying crop and soil types than to estimating of soil water content.

  20. Near Earth Asteroid Scout Solar Sail Thrust and Torque Model

    Science.gov (United States)

    Heaton, Andy; Ahmad, Naeem; Miller, Kyle

    2017-01-01

    The Near Earth Asteroid (NEA) Scout is a solar sail mission whose objective is to scout at least one Near Earth Asteroid to help prepare for human missions to Near Earth Asteroids. NEA Scout will launch as a secondary payload on the first SLS-Orion mission. NEA Scout will perform a small trim maneuver shortly after deploy from the spent SLS upper stage using a cold gas propulsion system, but from that point on will depend entirely on the solar sail for thrust. As such, it is important to accurately characterize the thrust of the sail in order to achieve mission success. Additionally, the solar sail creates a relatively large solar disturbance torque that must be mitigated. For early mission design studies a flat plate model of the solar sail with a fixed center of pressure was adequate, but as mission concepts and the sail design matured, greater fidelity was required. Here we discuss the progress to a three-dimensional sail model that includes the effects of tension and thermal deformation that has been derived from a large structural Finite Element Model (FEM) developed by the Langley Research Center. We have found that the deformed sail membrane affects torque relatively much more than thrust; a flat plate model could potentially model thrust well enough to close mission design studies, but a three-dimensional solar sail is essential to control system design. The three-dimensional solar sail model revealed that thermal deformations of unshielded booms would create unacceptably large solar disturbance torques. The original large FEM model was used in control and mission simulations, but was resulted in simulations with prohibitive run times. This led us to adapt the Generalized Sail Model (GSM) of Rios-Reyes. A design reference sail model has been baselined for NEA Scout and has been used to design the mission and control system for the sailcraft. Additionally, since NEA Scout uses reaction wheels for attitude pointing and control, the solar torque model is

  1. A Systematic Evaluation Model for Solar Cell Technologies

    Directory of Open Access Journals (Sweden)

    Chang-Fu Hsu

    2014-01-01

    Full Text Available Fossil fuels, including coal, petroleum, natural gas, and nuclear energy, are the primary electricity sources currently. However, with depletion of fossil fuels, global warming, nuclear crisis, and increasing environmental consciousness, the demand for renewable energy resources has skyrocketed. Solar energy is one of the most popular renewable energy resources for meeting global energy demands. Even though there are abundant studies on various solar technology developments, there is a lack of studies on solar technology evaluation and selection. Therefore, this research develops a model using interpretive structural modeling (ISM, benefits, opportunities, costs, and risks concept (BOCR, and fuzzy analytic network process (FANP to aggregate experts' opinions in evaluating current available solar cell technology. A case study in a photovoltaics (PV firm is used to examine the practicality of the proposed model in selecting the most suitable technology for the firm in manufacturing new products.

  2. Hawaii Solar Integration Study: Solar Modeling Developments and Study Results; Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Orwig, K.; Corbus, D.; Piwko, R.; Schuerger, M.; Matsuura, M.; Roose, L.

    2012-12-01

    The Hawaii Solar Integration Study (HSIS) is a follow-up to the Oahu Wind Integration and Transmission Study completed in 2010. HSIS focuses on the impacts of higher penetrations of solar energy on the electrical grid and on other generation. HSIS goes beyond the island of Oahu and investigates Maui as well. The study examines reserve strategies, impacts on thermal unit commitment and dispatch, utilization of energy storage, renewable energy curtailment, and other aspects of grid reliability and operation. For the study, high-frequency (2-second) solar power profiles were generated using a new combined Numerical Weather Prediction model/ stochastic-kinematic cloud model approach, which represents the 'sharp-edge' effects of clouds passing over solar facilities. As part of the validation process, the solar data was evaluated using a variety of analysis techniques including wavelets, power spectral densities, ramp distributions, extreme values, and cross correlations. This paper provides an overview of the study objectives, results of the solar profile validation, and study results.

  3. Solar Spectral Irradiance under Clear and Cloudy Skies: Measurements and a Semiempirical Model.

    Science.gov (United States)

    Nann, Stefan; Riordan, Carol

    1991-04-01

    In a combined effort, the Centre for Solar Energy and Hydrogen Research in Germany and the Solar Energy Research Institute in the United States analyzed several thousand measurements of the solar spectral irradiance recorded at four sites. The goal was to develop a semiempirical model that describes the total solar spectral irradiance for clear and cloudy sky conditions based on readily available input data.To investigate how the spectral transmission of clouds deviates from an assumed neutral density filter, the measured spectra are compared with simulated clear-sky spectra. A correlation is established between the cloud thickness and the relatively higher transmission of clouds in the ultraviolet and blue region of the solar spectrum. Using this approach, a semiempirical model is proposed based solely on global and diffuse broadband irradiance measurements, precipitable water-vapor data, and the sun's position. The model, called SEDESI, is applied to calculate spectral irradiance in short time steps (30 or 60 minutes) that are needed for either the design and performance analysis of spectrally selective solar energy conversion systems or to predict daylight availability. The results are also applicable to current climate research areas such as validating radiative transfer codes.

  4. First results from the NASA WB-57 airborne observations of the Great American 2017 Total Solar Eclipse

    Science.gov (United States)

    Caspi, Amir; Tsang, Constantine; DeForest, Craig; Seaton, Daniel B.; Bryans, Paul; Tomczyk, Steven; Burkepile, Joan; Judge, Phil; DeLuca, Edward E.; Golub, Leon; Gallagher, Peter T.; Zhukov, Andrei; West, Matthew; Durda, Daniel D.; Steffl, Andrew J.

    2017-08-01

    Total solar eclipses present rare opportunities to study the complex solar corona, down to altitudes of just a few percent of a solar radius above the surface, using ground-based and airborne observatories that would otherwise be dominated by the intense solar disk and high sky brightness. Studying the corona is critical to gaining a better understanding of physical processes that occur on other stars and astrophysical objects, as well as understanding the dominant driver of space weather that affects human assets at Earth and elsewhere. For example, it is still poorly understood how the corona is heated to temperatures of 1-2 MK globally and up to 5-10 MK above active regions, while the underlying chromosphere is 100 times cooler; numerous theories abound, but are difficult to constrain due to the limited sensitivities and cadences of prior measurements. The origins and stability of coronal fans, and the extent of their reach to the middle and outer corona, are also not well known, limited in large part by sensitivities and fields of view of existing observations.Airborne observations during the eclipse provide unique advantages; by flying in the stratosphere at altitudes of 50 kft or higher, they avoid all weather, the seeing quality is enormously improved, and additional wavelengths such as near-IR also become available due to significantly reduced water absorption. For an eclipse, an airborne observatory can also follow the shadow, increasing the total observing time by 50% or more.We present the first results from airborne observations of the 2017 Great American Total Solar Eclipse using two of NASA's WB-57 research aircraft, each equipped with two 8.7" telescopes feeding high-sensitivity visible (green-line) and near-IR (3-5 µm) cameras operating at high cadence (30 Hz) with ~3 arcsec/pixel platescale and ±3 R_sun fields of view. The aircraft will fly along the eclipse path, separated by ~90 km, to observe a summed ~8 minutes of totality in both visible and

  5. Modeling Polarized Solar Radiation for Correction of Satellite Data

    Science.gov (United States)

    Sun, W.

    2014-12-01

    Reflected solar radiation from the Earth-atmosphere system is polarized. If a non-polarimetric sensor has some polarization dependence, it can result in errors in the measured radiance. To correct the polarization-caused errors in satellite data, the polarization state of the reflected solar light must be known. In this presentation, recent studies of the polarized solar radiation from the ocean-atmosphere system with the adding-doubling radiative-transfer model (ADRTM) are reported. The modeled polarized solar radiation quantities are compared with PARASOL satellite measurements and DISORT model results. Sensitivities of reflected solar radiation's polarization to various ocean-surface and atmospheric conditions are addressed. A novel super-thin cloud detection method based on polarization measurements is also discussed. This study demonstrates that the modeling can provide a reliable approach for making the spectral Polarization Distribution Models (PDMs) for satellite inter-calibration applications of NASA's future Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Key words: Reflected solar radiation, polarization, correction of satellite data.

  6. A Model for Hourly Solar Radiation Data Generation from Daily Solar Radiation Data Using a Generalized Regression Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Tamer Khatib

    2015-01-01

    Full Text Available This paper presents a model for predicting hourly solar radiation data using daily solar radiation averages. The proposed model is a generalized regression artificial neural network. This model has three inputs, namely, mean daily solar radiation, hour angle, and sunset hour angle. The output layer has one node which is mean hourly solar radiation. The training and development of the proposed model are done using MATLAB and 43800 records of hourly global solar radiation. The results show that the proposed model has better prediction accuracy compared to some empirical and statistical models. Two error statistics are used in this research to evaluate the proposed model, namely, mean absolute percentage error and root mean square error. These values for the proposed model are 11.8% and −3.1%, respectively. Finally, the proposed model shows better ability in overcoming the sophistic nature of the solar radiation data.

  7. Solar optical codes evaluation for modeling and analyzing complex solar receiver geometries

    Science.gov (United States)

    Yellowhair, Julius; Ortega, Jesus D.; Christian, Joshua M.; Ho, Clifford K.

    2014-09-01

    Solar optical modeling tools are valuable for modeling and predicting the performance of solar technology systems. Four optical modeling tools were evaluated using the National Solar Thermal Test Facility heliostat field combined with flat plate receiver geometry as a benchmark. The four optical modeling tools evaluated were DELSOL, HELIOS, SolTrace, and Tonatiuh. All are available for free from their respective developers. DELSOL and HELIOS both use a convolution of the sunshape and optical errors for rapid calculation of the incident irradiance profiles on the receiver surfaces. SolTrace and Tonatiuh use ray-tracing methods to intersect the reflected solar rays with the receiver surfaces and construct irradiance profiles. We found the ray-tracing tools, although slower in computation speed, to be more flexible for modeling complex receiver geometries, whereas DELSOL and HELIOS were limited to standard receiver geometries such as flat plate, cylinder, and cavity receivers. We also list the strengths and deficiencies of the tools to show tool preference depending on the modeling and design needs. We provide an example of using SolTrace for modeling nonconventional receiver geometries. The goal is to transfer the irradiance profiles on the receiver surfaces calculated in an optical code to a computational fluid dynamics code such as ANSYS Fluent. This approach eliminates the need for using discrete ordinance or discrete radiation transfer models, which are computationally intensive, within the CFD code. The irradiance profiles on the receiver surfaces then allows for thermal and fluid analysis on the receiver.

  8. Solar total energy-large scale experiment, Shenandoah, Georgia site. Annual report, June 1977--June 1978. [For Bleyle Knitwear Plant

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1978-06-01

    The site was described in terms of location, suitably, accessibility, and other factors. Detailed descriptions of the Solar Total Energy-Large Scale Experiment Application (STE-LSE) (Bleyle of America, Inc., Knitwear Plant), the DOE owned Meteorology Station operating at the site, and the instrumentation provided by the Georgia Power Company to measure energy usage within the knitwear plant are included. A detailed report of progress is given at the Shenandoah Site, introduced by the STE-LSE schedule and the Cooperative Agreement work tasks. Progress is described in terms of the following major task areas: site/application; instrumentation/data acquisition; meteorology station; site to STES interface; information dissemination. A brief overview of milestones to be accomplished is given, followed by these appendices: solar easement agreement, interface drawing set, and additional site background data. (MHR)

  9. A potential lag between the open solar magnetic source flux and solar EUV and X-ray emissions as measured by the Earth's ionosphere during total solar eclipses

    Directory of Open Access Journals (Sweden)

    C. J. Davis

    2009-06-01

    Full Text Available Measurements of the ionospheric E-region during total solar eclipses have been used to provide information about the evolution of the solar magnetic field and EUV and X-ray emissions from the solar corona and chromosphere. By measuring levels of ionisation during an eclipse and comparing these measurements with an estimate of the unperturbed ionisation levels (such as those made during a control day, where available it is possible to estimate the percentage of ionising radiation being emitted by the solar corona and chromosphere. Previously unpublished data from the two eclipses presented here are particularly valuable as they provide information that supplements the data published to date. The eclipse of 23 October 1976 over Australia provides information in a data gap that would otherwise have spanned the years 1966 to 1991. The eclipse of 4 December 2002 over Southern Africa is important as it extends the published sequence of measurements. Comparing measurements from eclipses between 1932 and 2002 with the solar magnetic source flux reveals that changes in the solar EUV and X-ray flux lag the open source flux measurements by approximately 1.5 years. We suggest that this unexpected result comes about from changes to the relative size of the limb corona between eclipses, with the lag representing the time taken to populate the coronal field with plasma hot enough to emit the EUV and X-rays ionising our atmosphere.

  10. Improved Solar-Radiation-Pressure Models for GPS Satellites

    Science.gov (United States)

    Bar-Sever, Yoaz; Kuang, Da

    2006-01-01

    A report describes a series of computational models conceived as an improvement over prior models for determining effects of solar-radiation pressure on orbits of Global Positioning System (GPS) satellites. These models are based on fitting coefficients of Fourier functions of Sun-spacecraft- Earth angles to observed spacecraft orbital motions.

  11. Enhancement of Solar Energy Representation in the GCAM Model

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Steven J.; Volke, April C.; Delgado Arias, Sabrina

    2010-02-01

    The representation of solar technologies in a research version of the GCAM (formerly MiniCAM) integrated assessment model have been enhanced to add technologies, improve the underlying data, and improve the interaction with the rest of the model. We find that the largest potential impact from the inclusion of thermal Concentrating Solar Power plants, which supply a substantial portion of electric generation in sunny regions of the world. Drawing on NREL research, domestic Solar Hot Water technologies have also been added in the United States region where this technology competes with conventional electric and gas technologies. PV technologies are as implemented in the CCTP scenarios, drawing on NREL cost curves for the United States, extrapolated to other world regions using a spatial analysis of population and solar resources.

  12. High Performance Computing Application: Solar Dynamo Model Project II, Corona and Heliosphere Component Initialization, Integration and Validation

    Science.gov (United States)

    2015-06-24

    allocate solar heating into any location of the corona . Its total contribution depended on the integration of the unsigned magnetic flux at 1 Rs...AFRL-RD-PS- TR-2015-0028 AFRL-RD-PS- TR-2015-0028 HIGH PERFORMANCE COMPUTING APPLICATION: SOLAR DYNAMO MODEL PROJECT II; CORONA AND HELIOSPHERE...Dynamo Model Project II, Corona and Heliosphere Component Initialization, Integration and Validation 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  13. Performance of IRI-2012 model during a deep solar minimum and a maximum year over global equatorial regions

    Science.gov (United States)

    Kumar, Sanjay

    2016-06-01

    Present paper inspects the prediction capability of the latest version of the International Reference Ionosphere (IRI-2012) model in predicting the total electron content (TEC) over seven different equatorial regions across the globe during a very low solar activity phase 2009 and a high solar activity phase 2012. This has been carried out by comparing the ground-based Global Positioning System (GPS)-derived VTEC with those from the IRI-2012 model. The observed GPS-TEC shows the presence of winter anomaly which is prominent during the solar maximum year 2012 and disappeared during solar minimum year 2009. The monthly and seasonal mean of the IRI-2012 model TEC with IRI-NeQ topside has been compared with the GPS-TEC, and our results showed that the monthly and seasonal mean value of the IRI-2012 model overestimates the observed GPS-TEC at all the equatorial stations. The discrepancy (or over estimation) in the IRI-2012 model is found larger during solar maximum year 2012 than that during solar minimum year 2009. This is a contradiction to the results recently presented by Tariku (2015) over equatorial regions of Uganda. The discrepancy is found maximum during the December solstice and a minimum during the March equinox. The magnitude of discrepancy in the IRI-2012 model showed longitudinal dependent which maximized in western longitude sector during both the years 2009 and 2012. The significant discrepancy in the IRI-2012 model observed during the solar minimum year 2009 could be attributed to larger difference between F10.7 flux and EUV flux (26-34 nm) during low solar activity period 2007-2009 than that during high solar activity period 2010-2012. This suggests that to represent the solar activity impact in the IRI model, implementation of new solar activity indices is further required for its better performance.

  14. The reconstruction of solar activity in the context of solar dynamo modeling

    Science.gov (United States)

    Sokoloff, D.

    2017-01-01

    We discuss problems of interpretation of sunspot data for use in solar dynamo modelling. The variety of the current sunspot reconstructions of archival data creates substantial difficulties for such an endeavour. We suggest a possible strategy to avoid these problems. The point is that we have to accept the possibility of several solar activity reconstructions that are contradictory in detail, and have to compare several possible reconstructions with dynamo models. The point is that a given reconstruction may not cover all the time interval of interest because this reconstruction requires information unavailable at earlier or later times.

  15. Mathematical Modeling of Dual Intake Transparent Transpired Solar Collector

    OpenAIRE

    Thomas Semenou; Rousse, Daniel R.; Brice Le Lostec; Hervé F. Nouanegue; Pierre-Luc Paradis

    2015-01-01

    Nowadays, in several types of commercial or institutional buildings, a significant rise of transpired solar collectors used to preheat the fresh air of the building can be observed. Nevertheless, when the air mass flow rate is low, the collector efficiency collapses and a large amount of energy remains unused. This paper presents a simple yet effective mathematical model of a transparent transpired solar collector (TTC) with dual intake in order to remove stagnation problems in the plenum and...

  16. SRADLIB: A C Library for Solar Radiation Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Balenzategui, J. L. [Ciemat. Madrid (Spain)

    2000-07-01

    This document shows the result of an exhaustive study about the theoretical and numerical models available in the literature about solar radiation modelling. The purpose of this study is to develop or adapt mathematical models describing the solar radiation specifically for Spain locations as well as to create computer tools able to support the labour of researchers or engineers needing solar radiation data to solve or improve the technical or energetic performance of solar systems. As results of this study and revision, a C library (SRADLIB) is presented as a key for the compilation of the mathematical models from different authors, for the comparison among the different approaches and for its application in computer programs. Different topics related to solar radiation and its modelling are first discussed, including the assumptions and conventions adopted and describing the most accepted and used current state-of-the-art models. some typical problems in the numerical calculation of radiation values are also posed with the proposed solution. The document includes next a complete reference of the developed functions, with many examples of application and calculus. (Author) 24 refs.

  17. Totally Asymmetric Limit for Models of Heat Conduction

    Science.gov (United States)

    De Carlo, Leonardo; Gabrielli, Davide

    2017-08-01

    We consider one dimensional weakly asymmetric boundary driven models of heat conduction. In the cases of a constant diffusion coefficient and of a quadratic mobility we compute the quasi-potential that is a non local functional obtained by the solution of a variational problem. This is done using the dynamic variational approach of the macroscopic fluctuation theory (Bertini et al. in Rev Mod Phys 87:593, 2015). The case of a concave mobility corresponds essentially to the exclusion model that has been discussed in Bertini et al. (J Stat Mech L11001, 2010; Pure Appl Math 64(5):649-696, 2011; Commun Math Phys 289(1):311-334, 2009) and Enaud and Derrida (J Stat Phys 114:537-562, 2004). We consider here the convex case that includes for example the Kipnis-Marchioro-Presutti (KMP) model and its dual (KMPd) (Kipnis et al. in J Stat Phys 27:6574, 1982). This extends to the weakly asymmetric regime the computations in Bertini et al. (J Stat Phys 121(5/6):843-885, 2005). We consider then, both microscopically and macroscopically, the limit of large externalfields. Microscopically we discuss some possible totally asymmetric limits of the KMP model. In one case the totally asymmetric dynamics has a product invariant measure. Another possible limit dynamics has instead a non trivial invariant measure for which we give a duality representation. Macroscopically we show that the quasi-potentials of KMP and KMPd, which are non local for any value of the external field, become local in the limit. Moreover the dependence on one of the external reservoirs disappears. For models having strictly positive quadratic mobilities we obtain instead in the limit a non local functional having a structure similar to the one of the boundary driven asymmetric exclusion process.

  18. A Model for Optimizing the Combination of Solar Electricity Generation, Supply Curtailment, Transmission and Storage

    Science.gov (United States)

    Perez, Marc J. R.

    /south bearing. Using technical and economic data reflecting today's real costs for solar generation technology, storage and electric transmission in combination with this model, we determined the minimum cost combination of these solutions to transform the variable output from solar plants into 3 distinct output profiles: A constant output equivalent to a baseload power plant, a well-defined seasonally-variable output with no weather-induced variability and a variable output but one that is 100% predictable on a multi-day ahead basis. In order to do this, over 14,000 model runs were performed by varying the desired output profile, the amount of energy curtailment, the penetration of solar energy and the geographic region across the continental United States. Despite the cost of supplementary electric transmission, geographic interconnection has the potential to reduce the levelized cost of electricity when meeting any of the studied output profiles by over 65% compared to when only storage is used. Energy curtailment, despite the cost of underutilizing solar energy capacity, has the potential to reduce the total cost of electricity when meeting any of the studied output profiles by over 75% compared to when only storage is used. The three variability mitigation strategies are thankfully not mutually exclusive. When combined at their ideal levels, each of the regions studied saw a reduction in cost of electricity of over 80% compared to when only energy storage is used to meet a specified output profile. When including current costs for solar generation, transmission and energy storage, an optimum configuration can conservatively provide guaranteed baseload power generation with solar across the entire continental United States (equivalent to a nuclear power plant with no down time) for less than 0.19 per kilowatt-hour. If solar is preferentially clustered in the southwest instead of evenly spread throughout the United States, and we adopt future expected costs for solar

  19. Production of solar radiation bankable datasets from high-resolution solar irradiance derived with dynamical downscaling Numerical Weather prediction model

    Directory of Open Access Journals (Sweden)

    Yassine Charabi

    2016-11-01

    Full Text Available A bankable solar radiation database is required for the financial viability of solar energy project. Accurate estimation of solar energy resources in a country is very important for proper siting, sizing and life cycle cost analysis of solar energy systems. During the last decade an important progress has been made to develop multiple solar irradiance database (Global Horizontal Irradiance (GHI and Direct Normal Irradiance (DNI, using satellite of different resolution and sophisticated models. This paper assesses the performance of High-resolution solar irradiance derived with dynamical downscaling Numerical Weather Prediction model with, GIS topographical solar radiation model, satellite data and ground measurements, for the production of bankable solar radiation datasets. For this investigation, NWP model namely Consortium for Small-scale Modeling (COSMO is used for the dynamical downscaling of solar radiation. The obtained results increase confidence in solar radiation data base obtained from dynamical downscaled NWP model. The mean bias of dynamical downscaled NWP model is small, on the order of a few percents for GHI, and it could be ranked as a bankable datasets. Fortunately, these data are usually archived in the meteorological department and gives a good idea of the hourly, monthly, and annual incident energy. Such short time-interval data are valuable in designing and operating the solar energy facility. The advantage of the NWP model is that it can be used for solar radiation forecast since it can estimate the weather condition within the next 72–120 hours. This gives a reasonable estimation of the solar radiation that in turns can be used to forecast the electric power generation by the solar power plant.

  20. Application analysis of solar total energy systems to the residential sector. Volume II, energy requirements. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-07-01

    This project analyzed the application of solar total energy systems to appropriate segments of the residential sector and determined their market penetration potential. This volume covers the work done on energy requirements definition and includes the following: (1) identification of the single-family and multi-family market segments; (2) regionalization of the United States; (3) electrical and thermal load requirements, including time-dependent profiles; (4) effect of conservation measures on energy requirements; and (5) verification of simulated load data with real data.

  1. Influence of solar eclipse of November 3rd, 2013 on the total ozone column over Badajoz, Spain

    OpenAIRE

    Mateos, D.; M. Antón; Vaquero, J. M.

    2014-01-01

    The hybrid eclipse of November 3rd, 2013 was observed as partial with a magnitude equal to 0.126 from Badajoz (38^\\circ 53' N, 6^\\circ 58' W). The evolution of the Total Ozone Column (TOC) values during 4 hours was monitored using a Solar Light Microtops-II manual sun-photometer. Before the eclipse, TOC remained invariable ~280 Dobson Units (DU) for one hour and a half. Once the eclipse was started, a clear decrease in TOC occurred. After the eclipse maximum (with TOC = 273 DU), a rapid TOC r...

  2. Influence of solar eclipse of November 3rd, 2013 on the total ozone column over Badajoz, Spain

    CERN Document Server

    Mateos, D; Vaquero, J M

    2014-01-01

    The hybrid eclipse of November 3rd, 2013 was observed as partial with a magnitude equal to 0.126 from Badajoz (38^\\circ 53' N, 6^\\circ 58' W). The evolution of the Total Ozone Column (TOC) values during 4 hours was monitored using a Solar Light Microtops-II manual sun-photometer. Before the eclipse, TOC remained invariable ~280 Dobson Units (DU) for one hour and a half. Once the eclipse was started, a clear decrease in TOC occurred. After the eclipse maximum (with TOC = 273 DU), a rapid TOC recovery was observed. When the eclipse was over, TOC came back to values ~280 DU.

  3. Design of an efficient Fresnel-type lens utilizing double total internal reflection for solar energy collection.

    Science.gov (United States)

    Wallhead, Ian; Jiménez, Teresa Molina; Ortiz, Jose Vicente García; Toledo, Ignacio Gonzalez; Toledo, Cristóbal Gonzalez

    2012-11-05

    A novel of Fresnel-type lens for use as a solar collector has been designed which utilizes double total internal reflection (D-TIR) to optimize collection efficiency for high numerical aperture lenses (in the region of 0.3 to 0.6 NA). Results show that, depending on the numerical aperture and the size of the receiver, a collection efficiency theoretical improvement on the order of 20% can be expected with this new design compared with that of a conventional Fresnel lens.

  4. A new method for identifying possible causal relationships between CO2, total solar irradiance and global temperature change

    OpenAIRE

    Seip, Knut Lehre; Grøn, Øyvind

    2015-01-01

    We apply a novel method based upon “before” and “after” relationships to investigate and quantify interconnections between global temperature anomaly, GTA, as response variable, and greenhouse gases, CO2, and total solar irradiance, TSI, as candidate causal variables for the period 1880 to 2010. The most likely interpretations of our results for the 6 to 8 years cyclic components of the variables are that during the period 1929 to 1936 CO2 significantly leads GTA. However, during the period 1...

  5. Modelling heterogeneous interfaces for solar water splitting

    Science.gov (United States)

    Pham, Tuan Anh; Ping, Yuan; Galli, Giulia

    2017-04-01

    The generation of hydrogen from water and sunlight offers a promising approach for producing scalable and sustainable carbon-free energy. The key of a successful solar-to-fuel technology is the design of efficient, long-lasting and low-cost photoelectrochemical cells, which are responsible for absorbing sunlight and driving water splitting reactions. To this end, a detailed understanding and control of heterogeneous interfaces between photoabsorbers, electrolytes and catalysts present in photoelectrochemical cells is essential. Here we review recent progress and open challenges in predicting physicochemical properties of heterogeneous interfaces for solar water splitting applications using first-principles-based approaches, and highlights the key role of these calculations in interpreting increasingly complex experiments.

  6. Modelling heterogeneous interfaces for solar water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Tuan Anh; Ping, Yuan; Galli, Giulia

    2017-01-09

    The generation of hydrogen from water and sunlight others a promising approach for producing scalable and sustainable carbon-free energy. The key of a successful solar-to-fuel technology is the design of efficient, long-lasting and low-cost photoelectrochemical cells, which are responsible for absorbing sunlight and driving water splitting reactions. To this end, a detailed understanding and control of heterogeneous interfaces between photoabsorbers, electrolytes and catalysts present in photoelectrochemical cells is essential. Here we review recent progress and open challenges in predicting physicochemical properties of heterogeneous interfaces for solar water splitting applications using first-principles-based approaches, and highlights the key role of these calculations in interpreting increasingly complex experiments.

  7. Relationship between phases of quasi-decadal oscillations of total ozone and the 11-year solar cycle

    Science.gov (United States)

    Visheratin, K. N.

    2012-02-01

    Temporal variability of the relationship between the phases of quasi-decadal oscillations (QDOs) of total ozone (TO), measured at the Arosa station, and the Ri international sunspot number have been analyzed for the period of 1932-2009. Before the 1970s, the maximum phase of ozone QDOs lagged behind solar activity variations by about 2.5-2.8 years and later outstripped by about 1.5 years. We assumed that the TO QDOs in midlatitudes of the Northern Hemisphere were close to being in resonance with solar activity oscillations in the period from the mid-1960s to the mid-1970s and assessed the characteristic delay period of TO QDOs. The global distribution of phases and amplitudes of TO QDOs have been studied for the period from 1979 to 2008 based on satellite data. The maximum phase of TO QDOs first onsets in northern middle and high latitudes and coincides with the end of the growth phase of the 11-year solar cycle. In the tropics, the maximum oscillation phase lags behind by 0.5-1 year. The maximum phase lag near 40-50° S is about two years. The latitudinal variations of the phase of TO QDOs have been approximated.

  8. Response of low latitude D-region ionosphere to the Total Solar Eclipse of 22 July 2009, deduced from ELF/VLF analysis

    Science.gov (United States)

    Singh, A. K.; Singh, R.; Singh, A. K.

    2011-12-01

    increase in the effective width of the earth-ionosphere waveguide [Clivered et al., 2001] hence VLF reflection height. An increase in the height of this reflecting surface causes the waveguide "cutoff" frequency to decrease with a resulting decrease in phase velocity and increase in phase delay. Thus, the phase of the signal "lags," in accord with the observations. However, because of the 'decrease in "cutoff" frequency, the attenuation in the waveguide decreases, i.e., the amplitude of the signals increases. This is in accordance with the observed enhancement of the atmospherics/tweeks and increased amplitude strength. REFERENCES: Clilverd, M.A., C. J. Rodger, N. R. Thomsone, J. Lichtenberger, P. Steinbach, P. Cannon, and M. J. Angling, Total solar eclipse effects on VLF signals: Observations and modeling, Radio Sci. 36(4), 773 -788, 2001. Smith, L.G. (1972), Rocket observations of solar UV radiation during the eclipse of 7 March 1970, J. Atmos. Terr. Phys., 3(1), 601-611.

  9. Photometric analysis of the corona during the 20 March 2015 total solar eclipse: density structures, hydrostatic temperatures and magnetic field inference

    CERN Document Server

    Bazin, C; Wittich, R; Koutchmy, S; Mouette, J; Nitschelm, C

    2015-01-01

    We present some new accurate CCD photometry analysis of the white light solar corona at the time of the last 20 March 2015 total eclipse (airborne observations on a Falcon 7X and at ground-based Svalbard). We measured coronal brightness profiles taken along radial directions from 1.001 to 3 solar radii in the northern, southern and equatorial regions, after removing the F corona and the sky background. These studies allow to evaluate the density gradients, structures and temperature heterogeneity, by considering the Thomson scattering in white light of the K corona and also emissions of the EUV Fe XII 193A (1 to 2 MK) and Fe XI 171/174 (lower temperature) simultaneously observed by SDO/AIA and SWAP Proba2 space missions. Some dispersion between the regions is noticed. The limitation of the hydrostatic equilibrium assumption in the solar atmosphere is discussed as well as the contribution of the magnetic field pressure gradients as illustrated by a comparison with the model stationary magnetic corona from Pred...

  10. Dynamic Modeling of the Solar Field in Parabolic Trough Solar Power Plants

    Directory of Open Access Journals (Sweden)

    Lourdes A. Barcia

    2015-11-01

    Full Text Available Parabolic trough solar power plants use a thermal fluid to transfer thermal energy from solar radiation to a water-steam Rankine cycle in order to drive a turbine that, coupled to an electrical generator, produces electricity. These plants have a heat transfer fluid (HTF system with the necessary elements to transform solar radiation into heat and to transfer that thermal energy to the water-steam exchangers. In order to get the best possible performance in the Rankine cycle and, hence, in the thermal plant, it is necessary that the thermal fluid reach its maximum temperature when leaving the solar field (SF. Also, it is mandatory that the thermal fluid does not exceed the maximum operating temperature of the HTF, above which it degrades. It must be noted that the optimal temperature of the thermal fluid is difficult to obtain, since solar radiation can change abruptly from one moment to another. The aim of this document is to provide a model of an HTF system that can be used to optimize the control of the temperature of the fluid without interfering with the normal operation of the plant. The results obtained with this model will be contrasted with those obtained in a real plant.

  11. Solar Module Modeling, Simulation And Validation Under Matlab / Simulink

    Directory of Open Access Journals (Sweden)

    M.Diaw

    2016-09-01

    Full Text Available Solar modules are systems which convert sunlight into electricity using the physics of semiconductors. Mathematical modeling of these systems uses weather data such as irradiance and temperature as inputs. It provides the current, voltage or power as outputs, which allows plot the characteristic giving the intensity I as a function of voltage V for photovoltaic cells. In this work, we have developed a model for a diode of a Photovoltaic module under the Matlab / Simulink environment. From this model, we have plotted the characteristic curves I-V and P-V of solar cell for different values of temperature and sunlight. The validation has been done by comparing the experimental curve with power from a solar panel HORONYA 20W type with that obtained by the model.

  12. Total laparoscopic gastrocystoplasty: experimental technique in a porcine model

    Directory of Open Access Journals (Sweden)

    Frederico R. Romero

    2007-02-01

    Full Text Available OBJECTIVE: Describe a unique simplified experimental technique for total laparoscopic gastrocystoplasty in a porcine model. MATERIAL AND METHODS: We performed laparoscopic gastrocystoplasty on 10 animals. The gastroepiploic arch was identified and carefully mobilized from its origin at the pylorus to the beginning of the previously demarcated gastric wedge. The gastric segment was resected with sharp dissection. Both gastric suturing and gastrovesical anastomosis were performed with absorbable running sutures. The complete procedure and stages of gastric dissection, gastric closure, and gastrovesical anastomosis were separately timed for each laparoscopic gastrocystoplasty. The end-result of the gastric suturing and the bladder augmentation were evaluated by fluoroscopy or endoscopy. RESULTS: Mean total operative time was 5.2 (range 3.5 - 8 hours: 84.5 (range 62 - 110 minutes for the gastric dissection, 56 (range 28 - 80 minutes for the gastric suturing, and 170.6 (range 70 to 200 minutes for the gastrovesical anastomosis. A cystogram showed a small leakage from the vesical anastomosis in the first two cases. No extravasation from gastric closure was observed in the postoperative gastrogram. CONCLUSIONS: Total laparoscopic gastrocystoplasty is a feasible but complex procedure that currently has limited clinical application. With the increasing use of laparoscopy in reconstructive surgery of the lower urinary tract, gastrocystoplasty may become an attractive option because of its potential advantages over techniques using small and large bowel segments.

  13. Challenges of modeling solar disturbances' arrival times at the Earth

    Institute of Scientific and Technical Information of China (English)

    S. T. WU; Ai-Hua WANG; C. D. FRY; XueShang FENG; Chin-Chun WU; Murray DRYER

    2008-01-01

    In recent years remarkable advances have been made in the development of phys-ics based models of various parts of the solar-terrestrial system (see JASTP special issues, October, November 2004; February 2007). In this paper, we focus our dis-cussions in a specific region of the Sun to the Earth's environment (i.e. 1 AU). It is well-known that geomagnetic storms are caused by solar eruptions. The conse-quences of these storms include particle acceleration, solar wind impact on the Earth's magnetosphere and ionosphere, UV-EUV radiation effects on the lower at-mosphere, etc. One of the main challenges is to predict the arrival time at 1 AU of the solar disturbance. The prospects look good for an accurate, real-time forecast scheme built on the acquisition of solar, heliosphere and the near-Earth data and large-scale models. However, the accuracy of these models still needs improve-ment. We will discuss the present status of the models and challenges to improve the simulation models.

  14. Challenges of modeling solar disturbances’ arrival times at the Earth

    Institute of Scientific and Technical Information of China (English)

    C.; D.; FRY; Chin-Chun; WU; Murray; DRYER

    2008-01-01

    In recent years remarkable advances have been made in the development of phys-ics based models of various parts of the solar-terrestrial system (see JASTP special issues, October, November 2004; February 2007). In this paper, we focus our dis-cussions in a specific region of the Sun to the Earth’s environment (i.e. 1 AU). It is well-known that geomagnetic storms are caused by solar eruptions. The conse-quences of these storms include particle acceleration, solar wind impact on the Earth’s magnetosphere and ionosphere, UV-EUV radiation effects on the lower at-mosphere, etc. One of the main challenges is to predict the arrival time at 1 AU of the solar disturbance. The prospects look good for an accurate, real-time forecast scheme built on the acquisition of solar, heliosphere and the near-Earth data and large-scale models. However, the accuracy of these models still needs improve-ment. We will discuss the present status of the models and challenges to improve the simulation models.

  15. Multicriteria GIS modeling of wind and solar farms in Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Jason R. [Metropolitan State College of Denver, Department of Earth and Atmospheric Sciences, CB 22 P.O. Box 173362-22, Denver, CO 80217-3362 (United States)

    2010-10-15

    The majority of electricity and heat in Colorado comes from coal and natural gas; however, renewable energy sources will play an integral role in the state's energy future. Colorado is the 11th windiest state and has more than 250 sunny days per year. The objectives of this research are to: 1) determine which landcover classes are affiliated with high wind and solar potential; and 2) identify areas that are suitable for wind and solar farms using multicriteria GIS modelling techniques. Renewable potential (NREL wind speed measurements at 50 m above the ground and NREL annual insolation data), landcover, population density, federal lands, and distance to roads, transmission lines, and cities were reclassified according to their suitability. Each was assigned weights based on their relative importance to one another. Superb wind classes are located in high alpine areas. Unfortunately, these areas are not suitable for large-scale wind farm development due to their inaccessibility and location within a sensitive ecosystem. Federal lands have low wind potential. According to the GIS model, ideal areas for wind farm development are located in northeastern Colorado. About 41 850 km{sup 2} of the state has model scores that are in the 90-100% range. Although annual solar radiation varies slightly, inter-mountain areas receive the most insolation. As far as federal lands, Indian reservations have the greatest solar input. The GIS model indicates that ideal areas for solar development are located in northwestern Colorado and east of Denver. Only 191 km{sup 2} of the state had model scores that were in the 90-100% range. These results suggest that the variables used in this analysis have more of an effect at eliminating non-suitable areas for large-scale solar farms; a greater area exists for suitable wind farms. However, given the statewide high insolation values with minimal variance, solar projects may be better suited for small-scale residential or commercial

  16. HELIOS modelling of point-focusing solar concentrators

    Science.gov (United States)

    Strachan, J. W.; Mulholland, G. P.

    The modifications to the optical code HELIOS which are required in order to model point-focusing concentrators is presented. HELIOS simulates the optical behavior of reflecting heliostats and was written to model central receiver facilities, specifically that of the Solar Thermal Test Facility at Sandia National Laboratories in Albuquerque, New Mexico. This paper discusses the necessary changes to the HELIOS code and to its input files such that it can successfully model point-focusing concentrators while retaining its computational power. A point-focusing concentrator located at the Solar Thermal Test Facility is presented as a sample case.

  17. Reading The Sun: A Three Dimensional Visual Model of The Solar Environment During Solar Cycle 24

    Science.gov (United States)

    Carranza-fulmer, T. L.; Moldwin, M.

    2014-12-01

    The sun is a powerful force that has proven to our society that it has a large impact on our lives. Unfortunately, there is still a lack of awareness on how the sun is capable of affecting Earth. The over all idea of "Reading The Sun" installation is to help demonstrate how the sun impacts the Earth, by compiling various data sources from satellites (SOHO, SDO, and STERO) with solar and solar wind models (MAS and ENLIL) to create a comprehensive three dimensional display of the solar environment. It focuses on the current solar maximum of solar cycle 24 and a CME that impacted Earth's magnetic field on February 27, 2014, which triggered geomagnetic storms around the Earth's poles. The CME was an after-effect of a class X4.9 solar flare, which was released from the sun on February 25, 2014. "Reading The Sun" is a 48" x 48" x 48" hanging model of the sun with color coded open opposing magnetic field lines along with various layers of the solar atmosphere, the heliospheric current sheet, and the inner planets. At the center of the xyz axis is the sun with the open magnetic field lines and the heliospheric current sheet permeating inner planetary space. The xyz axes are color coded to represent various types of information with corresponding visual images for the viewer to be able to read the model. Along the z-axis are three colors (yellow, orange, and green) that represent the different layers of the solar atmosphere (photosphere, chromosphere, and corona) that correspond to three satellite images in various spectrums related to a CME and Solar Flare and the xy-plane shows where the inner planets are in relation to the sun. The exhibit in which "Reading The Sun "is being displayed is called, The Rotation of Language at the Wheather Again Gallery in Rockaway, New York. The intent of the exhibit is to both celebrate as well as present a cautionary tale on the ability of human language to spark and ignite the individual and collective imagination towards an experience

  18. Determination of the νe and total B8 solar neutrino fluxes using the Sudbury Neutrino Observatory Phase I data set

    Science.gov (United States)

    Aharmim, B.; Ahmad, Q. R.; Ahmed, S. N.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Bühler, G.; Barton, J. C.; Beier, E. W.; Bercovitch, M.; Bergevin, M.; Bigu, J.; Biller, S. D.; Black, R. A.; Blevis, I.; Boardman, R. J.; Boger, J.; Bonvin, E.; Boulay, M. G.; Bowler, M. G.; Bowles, T. J.; Brice, S. J.; Browne, M. C.; Bullard, T. V.; Burritt, T. H.; Cameron, J.; Chan, Y. D.; Chen, H. H.; Chen, M.; Chen, X.; Cleveland, B. T.; Cowan, J. H. M.; Cowen, D. F.; Cox, G. A.; Currat, C. A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W. F.; Deng, H.; Dimarco, M.; Doe, P. J.; Doucas, G.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Dunford, M.; Dunmore, J. A.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Ferraris, A. P.; Fleurot, F.; Ford, R. J.; Formaggio, J. A.; Fowler, M. M.; Frame, K.; Frank, E. D.; Frati, W.; Gagnon, N.; Germani, J. V.; Gil, S.; Goldschmidt, A.; Goon, J. T. M.; Graham, K.; Grant, D. R.; Guillian, E.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamer, A. S.; Hamian, A. A.; Handler, W. B.; Haq, R. U.; Hargrove, C. K.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Henning, R.; Hepburn, J. D.; Heron, H.; Hewett, J.; Hime, A.; Howard, C.; Howe, M. A.; Huang, M.; Hykaway, J. G.; Isaac, M. C. P.; Jagam, P.; Jamieson, B.; Jelley, N. A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P. T.; Kirch, K.; Klein, J. R.; Knox, A. B.; Komar, R. J.; Kormos, L. L.; Kos, M.; Kouzes, R.; Krüger, A.; Kraus, C.; Krauss, C. B.; Kutter, T.; Kyba, C. C. M.; Labranche, H.; Lange, R.; Law, J.; Lawson, I. T.; Lay, M.; Lee, H. W.; Lesko, K. T.; Leslie, J. R.; Levine, I.; Loach, J. C.; Locke, W.; Luoma, S.; Lyon, J.; MacLellan, R.; Majerus, S.; Mak, H. B.; Maneira, J.; Marino, A. D.; Martin, R.; McCauley, N.; McDonald, A. B.; McDonald, D. S.; McFarlane, K.; McGee, S.; McGregor, G.; Drees, R. Meijer; Mes, H.; Mifflin, C.; Miknaitis, K. K. S.; Miller, M. L.; Milton, G.; Moffat, B. A.; Monreal, B.; Moorhead, M.; Morrissette, B.; Nally, C. W.; Neubauer, M. S.; Newcomer, F. M.; Ng, H. S.; Nickel, B. G.; Noble, A. J.; Norman, E. B.; Novikov, V. M.; Oblath, N. S.; Okada, C. E.; O'Keeffe, H. M.; Ollerhead, R. W.; Omori, M.; Orrell, J. L.; Oser, S. M.; Ott, R.; Peeters, S. J. M.; Poon, A. W. P.; Prior, G.; Reitzner, S. D.; Rielage, K.; Roberge, A.; Robertson, B. C.; Robertson, R. G. H.; Rosendahl, S. S. E.; Rowley, J. K.; Rusu, V. L.; Saettler, E.; Schülke, A.; Schwendener, M. H.; Secrest, J. A.; Seifert, H.; Shatkay, M.; Simpson, J. J.; Sims, C. J.; Sinclair, D.; Skensved, P.; Smith, A. R.; Smith, M. W. E.; Starinsky, N.; Steiger, T. D.; Stokstad, R. G.; Stonehill, L. C.; Storey, R. S.; Sur, B.; Tafirout, R.; Tagg, N.; Takeuchi, Y.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Thornewell, P. M.; Tolich, N.; Trent, P. T.; Tserkovnyak, Y. I.; Tsui, T.; Tunnell, C. D.; van Berg, R.; van de Water, R. G.; Virtue, C. J.; Walker, T. J.; Wall, B. L.; Waltham, C. E.; Tseung, H. Wan Chan; Wang, J.-X.; Wark, D. L.; Wendland, J.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J. R.; Wittich, P.; Wouters, J. M.; Wright, A.; Yeh, M.; Zuber, K.

    2007-04-01

    This article provides the complete description of results from the Phase I data set of the Sudbury Neutrino Observatory (SNO). The Phase I data set is based on a 0.65 kiloton-year exposure of 2H2O (in the following denoted as D2O) to the solar B8 neutrino flux. Included here are details of the SNO physics and detector model, evaluations of systematic uncertainties, and estimates of backgrounds. Also discussed are SNO's approach to statistical extraction of the signals from the three neutrino reactions (charged current, neutral current, and elastic scattering) and the results of a search for a day-night asymmetry in the νe flux. Under the assumption that the B8 spectrum is undistorted, the measurements from this phase yield a solar νe flux of ϕ(νe)=1.76-0.05+0.05(stat.)-0.09+0.09(syst.)×106 cm-2 s-1 and a non-νe component of ϕ(νμτ)=3.41-0.45+0.45(stat.)-0.45+0.48(syst.)×106 cm-2 s-1. The sum of these components provides a total flux in excellent agreement with the predictions of standard solar models. The day-night asymmetry in the νe flux is found to be Ae=7.0±4.9(stat.)-1.2+1.3%(syst.), when the asymmetry in the total flux is constrained to be zero.

  19. Modeling and verification of hemispherical solar still using ANSYS CFD

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Hitesh N. [KSV University, Gujarat Power Engineering and Research Institute, Mehsana (India); Shah, P.K. [Silver Oak College of Engineering and Technology, Ahmedabad, Gujarat (India)

    2013-07-01

    In every efficient solar still design, water temperature, vapor temperature and distillate output, and difference between water temperature and inner glass cover temperatures are very important. Here, two dimensional three phase model of hemispherical solar still is made for evaporation as well as condensation process in ANSYS CFD. Simulation results like water temperature, vapor temperature, distillate output compared with actual experimental results of climate conditions of Mehsana (latitude of 23° 59’ and longitude of 72° 38) of hemispherical solar still. Water temperature and distillate output were good agreement with actual experimental results. Study shows that ANSYS-CFD is very powerful as well as efficient tool for design, comparison purpose of hemispherical solar still.

  20. Modelling the influence of photospheric turbulence on solar flare statistics

    Science.gov (United States)

    Mendoza, M.; Kaydul, A.; de Arcangelis, L.; Andrade, J. S., Jr.; Herrmann, H. J.

    2014-09-01

    Solar flares stem from the reconnection of twisted magnetic field lines in the solar photosphere. The energy and waiting time distributions of these events follow complex patterns that have been carefully considered in the past and that bear some resemblance with earthquakes and stockmarkets. Here we explore in detail the tangling motion of interacting flux tubes anchored in the plasma and the energy ejections resulting when they recombine. The mechanism for energy accumulation and release in the flow is reminiscent of self-organized criticality. From this model, we suggest the origin for two important and widely studied properties of solar flare statistics, including the time-energy correlations. We first propose that the scale-free energy distribution of solar flares is largely due to the twist exerted by the vorticity of the turbulent photosphere. Second, the long-range temporal and time-energy correlations appear to arise from the tube-tube interactions. The agreement with satellite measurements is encouraging.

  1. A pebbles accretion model with chemistry and implications for the solar system

    CERN Document Server

    Ali-Dib, Mohamad

    2016-01-01

    We investigate the chemical composition of the solar system's giant planets atmospheres using a physical formation model with chemistry. The model incorporate disk evolution, pebbles and gas accretion, type I and II migration, simplified disk photoevaporation and solar system chemical measurements. We track the chemical compositions of the formed giant planets and compare them to the observed values. Two categories of models are studied: with and without disk chemical enrichment via photoevaporation. Predictions for the Oxygen and Nitrogen abundances, core masses, and total amount of heavy elements for the planets are made for each case. We find that in the case without disk PE, both Jupiter and Saturn will have a small residual core and comparable total amounts of heavy elements in the envelopes. We predict oxygen abundances enrichments in the same order as carbon, phosphorus and sulfur for both planets. Cometary Nitrogen abundances does not allow to easily reproduce Jupiter's nitrogen observations. In the c...

  2. Generic phase coexistence in the totally asymmetric kinetic Ising model

    Science.gov (United States)

    Godrèche, Claude; Luck, Jean-Marc

    2017-07-01

    The physical analysis of generic phase coexistence in the North-East-Center Toom model was originally given by Bennett and Grinstein. The gist of their argument relies on the dynamics of interfaces and droplets. We revisit the same question for a specific totally asymmetric kinetic Ising model on the square lattice. This nonequilibrium model possesses the remarkable property that its stationary-state measure in the absence of a magnetic field coincides with that of the usual ferromagnetic Ising model. We use both analytical arguments and numerical simulations in order to make progress in the quantitative understanding of the phenomenon of generic phase coexistence. At zero temperature a mapping onto the TASEP allows an exact determination of the time-dependent shape of the ballistic interface sweeping a large square minority droplet of up or down spins. At finite temperature, measuring the mean lifetime of such a droplet allows an accurate measurement of its shrinking velocity v, which depends on temperature T and magnetic field h. In the absence of a magnetic field, v vanishes with an exponent Δ_v≈2.5+/-0.2 as the critical temperature T c is approached. At fixed temperature in the ordered phase, v vanishes at the phase-boundary fields +/- h_b(T) which mark the limits of the coexistence region. The latter fields vanish with an exponent Δ_h≈3.2+/-0.3 as T c is approached.

  3. Multi-scale comparative spectral analysis of satellite total solar irradiance measurements from 2003 to 2013 reveals a planetary modulation of solar activity and its non-linear dependence on the 11-year solar cycle

    CERN Document Server

    Scafetta, Nicola

    2013-01-01

    Herein we adopt a multi-scale dynamical spectral analysis technique to compare and study the dynamical evolution of the harmonic components of the overlapping ACRIMSAT/ACRIM3, SOHO/VIRGO and SORCE/TIM total solar irradiance (TSI) records during 2003.15 to 2013.16 in solar cycles 23 and 24. The three TSI time series present highly correlated patterns. Significant power spectral peaks are common to these records and are observed at the following periods: 0.070 year, 0.097 year, 0.20 year, 0.25 year, 0.30-0.34 year, 0.39 year. Less certain spectral peaks occur at about 0.55 year, 0.60-0.65 year and 0.7-0.9 year. Four main frequency periods at 24.8 days (0.068 year), 27.3 days (0.075 year), at 34-35 days (0.093-0.096 year) and 36-38 days (0.099-0.104 year) characterize the solar rotation cycle. The amplitude of these oscillations, in particular of those with periods larger than 0.5 year, appears to be modulated by the 11-year solar cycle. Similar harmonics have been found in other solar indices. The observed peri...

  4. Validation, Optimization and Simulation of a Solar Thermoelectric Generator Model

    Science.gov (United States)

    Madkhali, Hadi Ali; Hamil, Ali; Lee, HoSung

    2017-08-01

    This study explores thermoelectrics as a viable option for small-scale solar thermal applications. Thermoelectric technology is based on the Seebeck effect, which states that a voltage is induced when a temperature gradient is applied to the junctions of two differing materials. This research proposes to analyze, validate, simulate, and optimize a prototype solar thermoelectric generator (STEG) model in order to increase efficiency. The intent is to further develop STEGs as a viable and productive energy source that limits pollution and reduces the cost of energy production. An empirical study (Kraemer et al. in Nat Mater 10:532, 2011) on the solar thermoelectric generator reported a high efficiency performance of 4.6%. The system had a vacuum glass enclosure, a flat panel (absorber), thermoelectric generator and water circulation for the cold side. The theoretical and numerical approach of this current study validated the experimental results from Kraemer's study to a high degree. The numerical simulation process utilizes a two-stage approach in ANSYS software for Fluent and Thermal-Electric Systems. The solar load model technique uses solar radiation under AM 1.5G conditions in Fluent. This analytical model applies Dr. Ho Sung Lee's theory of optimal design to improve the performance of the STEG system by using dimensionless parameters. Applying this theory, using two cover glasses and radiation shields, the STEG model can achieve a highest efficiency of 7%.

  5. The solar diameter on 9 March 2016, from the total eclipse in Micronesia: at its standard value

    Science.gov (United States)

    Sigismondi, Costantino; Castiglioni, Francesco; Cicogna, Domenico; Cardoso, Felipe

    2016-05-01

    The total eclipse of 9 March 2016 has been observed in Woleai atoll (Micronesia) by the Exploratorium team and posted in youtube. Exploiting the ghost images of that video we overcome the overexposition problems when dealing with the transition photosphere/chromosphere, dealing with Baily's beads around totality comparable with the intensity of the corona. A correction to the standard value of the solar radius R=959.63" of ΔR=+0.01"±0.02" has been found, contrarily to the recent values near 960.0" with the last eclipses and transit of Venus. Perspectives for the measures to be done during the forthcoming transit of Mercury are drafted.

  6. A review on solar wind modeling: kinetic and fluid aspects

    CERN Document Server

    Echim, Marius; Lie-Svendsen, Oystein

    2013-01-01

    We review the main advantages and limitations of the kinetic exospheric and fluid models of the solar wind (SW). We discuss the hydrostatic model imagined by Chapman, the first supersonic hydrodynamic models published by Parker and the first generation subsonic kinetic model proposed by Chamberlain. It is shown that a correct estimation of the electric field as in the second generation kinetic exospheric models developed by Lemaire and Scherer, provides a supersonic expansion of the corona, reconciling the hydrodynamic and the kinetic approach. The third generation kinetic exospheric models considers kappa velocity distribution function (VDF) instead of a Maxwellian at the exobase and in addition they treat a non-monotonic variation of the electric potential with the radial distance; the fourth generation exospheric models include Coulomb collisions based on the Fokker--Planck collision term. Multi-fluid models of the solar wind provide a coarse grained description and reproduce with success the spatio-tempor...

  7. Large scale solar district heating. Evaluation, modelling and designing

    Energy Technology Data Exchange (ETDEWEB)

    Heller, A.

    2000-07-01

    The main objective of the research was to evaluate large-scale solar heating connected to district heating (CSDHP), to build up a simulation tool and to demonstrate the application of the tool for design studies and on a local energy planning case. The evaluation of the central solar heating technology is based on measurements on the case plant in Marstal, Denmark, and on published and unpublished data for other, mainly Danish, CSDHP plants. Evaluations on the thermal, economical and environmental performances are reported, based on the experiences from the last decade. The measurements from the Marstal case are analysed, experiences extracted and minor improvements to the plant design proposed. For the detailed designing and energy planning of CSDHPs, a computer simulation model is developed and validated on the measurements from the Marstal case. The final model is then generalised to a 'generic' model for CSDHPs in general. The meteorological reference data, Danish Reference Year, is applied to find the mean performance for the plant designs. To find the expectable variety of the thermal performance of such plants, a method is proposed where data from a year with poor solar irradiation and a year with strong solar irradiation are applied. Equipped with a simulation tool design studies are carried out spreading from parameter analysis over energy planning for a new settlement to a proposal for the combination of plane solar collectors with high performance solar collectors, exemplified by a trough solar collector. The methodology of utilising computer simulation proved to be a cheap and relevant tool in the design of future solar heating plants. The thesis also exposed the demand for developing computer models for the more advanced solar collector designs and especially for the control operation of CSHPs. In the final chapter the CSHP technology is put into perspective with respect to other possible technologies to find the relevance of the application

  8. Solar Position Model for use in DIORAMA

    Energy Technology Data Exchange (ETDEWEB)

    Werley, Kenneth Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-01

    The DIORAMA code requires the solar position relative to earth in order to compute GPS satellite orientation. The present document describes two functions that compute the unit vector from either the center of the Earth to the Sun or from any observer’s position to the Sun at some specified time. Another function determines if a satellite lies within the Earth’s shadow umbra. Similarly, functions determine the position of the moon and whether a satellite lies within the Moon’s shadow umbra.

  9. Silicon Nanowire/Polymer Hybrid Solar Cell-Supercapacitor: A Self-Charging Power Unit with a Total Efficiency of 10.5.

    Science.gov (United States)

    Liu, Ruiyuan; Wang, Jie; Sun, Teng; Wang, Mingjun; Wu, Changsheng; Zou, Haiyang; Song, Tao; Zhang, Xiaohong; Lee, Shuit-Tong; Wang, Zhong Lin; Sun, Baoquan

    2017-07-12

    An integrated self-charging power unit, combining a hybrid silicon nanowire/polymer heterojunction solar cell with a polypyrrole-based supercapacitor, has been demonstrated to simultaneously harvest solar energy and store it. By efficiency enhancement of the hybrid nanowire solar cells and a dual-functional titanium film serving as conjunct electrode of the solar cell and supercapacitor, the integrated system is able to yield a total photoelectric conversion to storage efficiency of 10.5%, which is the record value in all the integrated solar energy conversion and storage system. This system may not only serve as a buffer that diminishes the solar power fluctuations from light intensity, but also pave its way toward cost-effective high efficiency self-charging power unit. Finally, an integrated device based on ultrathin Si substrate is demonstrated to expand its feasibility and potential application in flexible energy conversion and storage devices.

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

    Science.gov (United States)

    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

  11. Non-homogeneous solar models with metal enriched envelopes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Solar models with enhancement of heavy elements in the convectiveenvelopes are investigated using the updated input physics. Unlike previous low-Z models that adopt quite low central metal abundance to considerably reduce neutrino fluxes, we investigate the effects of moderate enrichment of heavy elements in the solar convection zone on the solar structure and p-mode oscillations. It is found that the metal enriched models have less massive convection zones with deeper bottom boundaries, and their temperature profiles are systematically lower while the sound speed profiles are higher in the interior and lower in the envelope than that of the standard model. The contamination of heavy elements at different evolution phases is investigated, which results in little influence on the properties of the solar age models. The surface helium abundance is reduced considerably, and is able to approach the seismically determined value when the enhancement of heavy elements in the convection zone is carefully adjusted. The p-mode frequency patterns of our metal enriched models are systematically 10 μHz lower than those of the standard model, and are in better agreement with the results of observations.

  12. Reliability models applicable to space telescope solar array assembly system

    Science.gov (United States)

    Patil, S. A.

    1986-01-01

    A complex system may consist of a number of subsystems with several components in series, parallel, or combination of both series and parallel. In order to predict how well the system will perform, it is necessary to know the reliabilities of the subsystems and the reliability of the whole system. The objective of the present study is to develop mathematical models of the reliability which are applicable to complex systems. The models are determined by assuming k failures out of n components in a subsystem. By taking k = 1 and k = n, these models reduce to parallel and series models; hence, the models can be specialized to parallel, series combination systems. The models are developed by assuming the failure rates of the components as functions of time and as such, can be applied to processes with or without aging effects. The reliability models are further specialized to Space Telescope Solar Arrray (STSA) System. The STSA consists of 20 identical solar panel assemblies (SPA's). The reliabilities of the SPA's are determined by the reliabilities of solar cell strings, interconnects, and diodes. The estimates of the reliability of the system for one to five years are calculated by using the reliability estimates of solar cells and interconnects given n ESA documents. Aging effects in relation to breaks in interconnects are discussed.

  13. The analysis of total solar eclipse observations on August 11th, 1999 in Kikinda

    Directory of Open Access Journals (Sweden)

    Popović G.M.

    2001-01-01

    Full Text Available Because of poor meteorological conditions, the obtained observational material has not an even distribution in time. Therefore a special method was devised for treating this material. Using this method the durations of total and partial phases of this eclipse were established.

  14. Effect of uncertainties in solar synoptic magnetic flux maps in modeling of solar wind

    Science.gov (United States)

    Pevtsov, Alexei A.; Bertello, Luca; MacNeice, Peter

    2015-12-01

    Recently, the NSO/SOLIS team developed variance (error) maps that represent uncertainties in magnetic flux synoptic charts. These uncertainties are determined by the spatial variances of the magnetic flux distribution from full disk magnetograms that contribute to each bin in the synoptic chart. Here we present a study of the effects of variances on solar wind parameters (wind speed, density, magnetic field, and temperature) derived using the WSA-ENLIL model and ensemble modeling approach. We compare the results of the modeling with near-Earth solar wind magnetic field and plasma data as extracted from NASA/GSFC's OMNI data set. We show that analysis of uncertainties may be useful for understanding the sensitivity of the model predictions to short-term evolution of magnetic field and noise in the synoptic magnetograms.

  15. Suggestion of a Management Model: Total Entropy Management

    Directory of Open Access Journals (Sweden)

    Goksel Alpan,

    2011-01-01

    Full Text Available “Entropy” can be defined as the measure of disorder, uncertainty and consumed energy in a system or in the Universe. In the study, entropy concept is used as metaphor and it is aimed to construct the conceptual basis of a new management model which can be utilized to manage all entropy sources effectively. The study is conveyed with a multidisciplinary and holistic approach and by the use of qualitative research techniques. In the study, it is examined the relations of the entropy concept with different disciplines like civilization history, sociology, economy, political sciences, ecology, environmental ethics, classical physics, quantum physics, nanotechnology, genetic science, information theory, network science, system theory, business management etc. and after the evaluation of the findings, it is constructed the conceptual basis of a new management model. At the beginning of the study, entropy concept is defined in detail and related concepts like social entropy, information entropy, negative entropy, heat death, matter chaos, entropic efficiency etc. are explained. Afterwards, important global entropy sources are examined and relations of the concept with actual political, economical, ecological, social and managerial problems and concepts are explained. The main aim of the study is to construct the conceptual basis of a new management model called “Total Entropy Management” which can be applied to governmental organizations, non profit organizations and business enterprises to be able to manage all entropy sources effectively.

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

    Science.gov (United States)

    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.

  17. Solar models with new low-metal abundances

    CERN Document Server

    Yang, Wuming

    2016-01-01

    In the last decade, the photospheric abundances of the Sun had been revised several times by many observers. The standard solar models (SSM) constructed with the new low-metal abundances disagree with helioseismic results and detected neutrino fluxes. The solar model problem has been puzzled some stellar physicists for more than ten years. Rotation, enhanced diffusion, convection overshoot, and magnetic fields are used to reconcile the new abundances with helioseismology. The \\textbf{too} low-helium \\textbf{subsurface abundance} in enhanced diffusion models can be improved by the mixing caused by rotation and magnetic fields. The problem of the depth of the convective zone in rotating models can be resolved by convection overshoot. Consequently the Asplund-Grevesse-Sauval rotation model including overshooting (AGSR) reproduces the seismically inferred sound-speed and density profiles, and the convection zone depth as well as the Grevesse and Sauval (GS98) model computed before. But this model fails to reprodu...

  18. Developing a Total Quality Management Model for Health Care Systems

    Directory of Open Access Journals (Sweden)

    AM Mosadegh Rad

    2005-10-01

    Full Text Available Background: Total quality management (TQM is a managerial practice to improve the effectiveness, efficiency, flexibility, and competitiveness of a business as a whole. However, in practice, these TQM benefits are not easy to achieve. Despite its theoretical promise and the enthusiastic response to TQM, recent evidence suggests that attempts to implement it are often unsuccessful. Many of these TQM programmes have been cancelled, or are in the process of being cancelled, as a result of the negative impact on profits. Therefore, there is a pressing need for a clinical approach to establishing TQM. Method: The aim of this article is therefore: “To identify the strengths and weakness of TQM, the logical steps towards TQM, and to develop a model so that health care organizations aiming at using TQM to achieve excellence can follow through easily”. Based on the research questions proposed in this study, the research strategies of a literature review, a questionnaire survey, semi-structured interviews, and a participatory action research were adopted in this study. For determining the success and barriers of TQM in health care organizations, a questionnaire survey has done in 90 health acre organizations in Isfahan Province, which implement TQM. The results of this survey were used for introducing a new model of TQM. This model will be developed via a semi-structured interview with at minimum 10 health care and quality managers. Then, through a participatory action research, this model will be implemented in 3 sites. At this time, the questionnaire survey has done and the model is introduced. Therefore, developing the model and its implementation will be done later. Results: In this survey, the mean score of TQM success was 3.48±0.68 (medium from 5 credits. Implementation of TQM was very low, low, medium, high and very high successful respectively in 3.6, 10.9, 21.8, 56.4 and 7.3 percent of health care organizations. TQM had the most effect on

  19. NLTE solar irradiance modeling with the COSI code

    CERN Document Server

    Shapiro, A I; Schoell, M; Haberreiter, M; Rozanov, E

    2010-01-01

    Context. The solar irradiance is known to change on time scales of minutes to decades, and it is suspected that its substantial fluctua- tions are partially responsible for climate variations. Aims. We are developing a solar atmosphere code that allows the physical modeling of the entire solar spectrum composed of quiet Sun and active regions. This code is a tool for modeling the variability of the solar irradiance and understanding its influence on Earth. Methods. We exploit further development of the radiative transfer code COSI that now incorporates the calculation of molecular lines. We validated COSI under the conditions of local thermodynamic equilibrium (LTE) against the synthetic spectra calculated with the ATLAS code. The synthetic solar spectra were also calculated in non-local thermodynamic equilibrium (NLTE) and compared to the available measured spectra. In doing so we have defined the main problems of the modeling, e.g., the lack of opacity in the UV part of the spectrum and the inconsistency in...

  20. An Update to the NASA Reference Solar Sail Thrust Model

    Science.gov (United States)

    Heaton, Andrew F.; Artusio-Glimpse, Alexandra B.

    2015-01-01

    An optical model of solar sail material originally derived at JPL in 1978 has since served as the de facto standard for NASA and other solar sail researchers. The optical model includes terms for specular and diffuse reflection, thermal emission, and non-Lambertian diffuse reflection. The standard coefficients for these terms are based on tests of 2.5 micrometer Kapton sail material coated with 100 nm of aluminum on the front side and chromium on the back side. The original derivation of these coefficients was documented in an internal JPL technical memorandum that is no longer available. Additionally more recent optical testing has taken place and different materials have been used or are under consideration by various researchers for solar sails. Here, where possible, we re-derive the optical coefficients from the 1978 model and update them to accommodate newer test results and sail material. The source of the commonly used value for the front side non-Lambertian coefficient is not clear, so we investigate that coefficient in detail. Although this research is primarily designed to support the upcoming NASA NEA Scout and Lunar Flashlight solar sail missions, the results are also of interest to the wider solar sail community.

  1. Broadband Radio Spectral Observations of Solar Eclipse on 2008-08-01 and Implications on the Quiet Sun Atmospheric Model

    CERN Document Server

    Tan, Baolin; Zhang, Yin; Tan, Chengmin; Huang, Jing; Liu, Yuying; Fu, Qijun; Chen, ZhiJun; Liu, Fei; Chen, Linjie; Ji, Guoshu; 10.1007/s11433-009-0230-y

    2009-01-01

    Based on the joint-observations of the radio broadband spectral emissions of solar eclipse on August 1, 2008 at Jiuquan (total eclipse) and Huairou (partial eclipse) at the frequencies of 2.00 -- 5.60 GHz (Jiuquan), 2.60 -- 3.80 GHZ (Chinese solar broadband radiospectrometer, SBRS/Huairou), and 5.20 -- 7.60 GHz (SBRS/Huairou), the authors assemble a successive series of broadband spectrum with a frequency of 2.60 -- 7.60 GHz to observe the solar eclipse synchronously. This is the first attempt to analyze the solar eclipse radio emission under the two telescopes located at different places with broadband frequencies in the periods of total and partial eclipse. With these analyses, the authors made a new semiempirical model of the coronal plasma density of the quiet Sun and made a comparison with the classic models.

  2. Spatial Modelling of Solar energy Potential in Kenya

    Directory of Open Access Journals (Sweden)

    Francis Omondi Oloo

    2015-06-01

    Full Text Available Solar energy is one of the readily available renewable energy resources in the developing countries within the tropical region. Kenya is one of the countries which receive an average of approximately 6.5 sunshine hours in a single day throughout the year. However, there is slow adoption of solar energy resources in the country due to limited information on the spatial variability solar energy potential. This study aims at assessing the potential of photovoltaic solar energy in Kenya. The factors that influence incident solar radiation which were considered in this task included atmospheric transmissivity and topography. The influence of atmospheric transmissivity was factored in by modelling monthly transmissivity factors from a combination of cloud cover, diffuse ratios and the effect of altitude. The contribution of topography was included by applying hemispherical viewshed analysis to determine the amount of incident global radiation on the surface based on the orientation of the terrain. GIS concepts were used to integrate the spatial datasets from different themes. The results showed that, about 70% of the land area in Kenya has the potential of receiving approximately 5kWh/m2/day throughout the year. In outline, this work successfully assessed the spatio-temporal variability in the characteristics of solar energy potential in Kenya and can be used as a basis for policy support in the country.

  3. Model of spacecraft atomic oxygen and solar exposure microenvironments

    Science.gov (United States)

    Bourassa, R. J.; Pippin, H. G.

    1993-01-01

    Computer models of environmental conditions in Earth orbit are needed for the following reasons: (1) derivation of material performance parameters from orbital test data, (2) evaluation of spacecraft hardware designs, (3) prediction of material service life, and (4) scheduling spacecraft maintenance. To meet these needs, Boeing has developed programs for modeling atomic oxygen (AO) and solar radiation exposures. The model allows determination of AO and solar ultraviolet (UV) radiation exposures for spacecraft surfaces (1) in arbitrary orientations with respect to the direction of spacecraft motion, (2) overall ranges of solar conditions, and (3) for any mission duration. The models have been successfully applied to prediction of experiment environments on the Long Duration Exposure Facility (LDEF) and for analysis of selected hardware designs for deployment on other spacecraft. The work on these models has been reported at previous LDEF conferences. Since publication of these reports, a revision has been made to the AO calculation for LDEF, and further work has been done on the microenvironments model for solar exposure.

  4. Curve fitting methods for solar radiation data modeling

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Samsul Ariffin Abdul, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my; Singh, Balbir Singh Mahinder, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my [Department of Fundamental and Applied Sciences, Faculty of Sciences and Information Technology, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)

    2014-10-24

    This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R{sup 2}. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.

  5. The solar dynamo: inferences from observations and modeling

    CERN Document Server

    Kitchatinov, L L

    2014-01-01

    It can be shown on observational grounds that two basic effects of dynamo theory for solar activity - production of the toroidal field from the poloidal one by differential rotation and reverse conversion of the toroidal field to the poloidal configuration by helical motions - are operating in the Sun. These two effects, however, do not suffice for constructing a realistic model for the solar dynamo. Only when a non-local version of the alpha-effect is applied, is downward diamagnetic pumping included and field advection by the equatorward meridional flow near the base of the convection zone allowed for, can the observed activity cycles be closely reproduced. Fluctuations in the alpha-effect can be estimated from sunspot data. Dynamo models with fluctuating parameters reproduce irregularities of solar cycles including the grand activity minima. The physics of parametric excitation of irregularities remains, however, to be understood.

  6. Curve fitting methods for solar radiation data modeling

    Science.gov (United States)

    Karim, Samsul Ariffin Abdul; Singh, Balbir Singh Mahinder

    2014-10-01

    This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R2. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.

  7. On the connections between solar and stellar dynamo models

    Science.gov (United States)

    Jouve, Laurène; Kumar, Rohit

    2017-10-01

    We here discuss the various dynamo models which have been designed to explain the generation and evolution of large-scale magnetic fields in stars. We focus on the models that have been applied to the Sun and can be tested for other solar-type stars now that modern observational techniques provide us with detailed stellar magnetic field observations. Mean-field flux-transport dynamo models have been developed for decades to explain the solar cycle and applications to more rapidly-rotating stars are discussed. Tremendous recent progress has been made on 3D global convective dynamo models. They do not however for now produce regular flux emergence that could be responsible for surface active regions and questions about the role of these active regions in the dynamo mechanism are still difficult to address with such models. We finally discuss 3D kinematic dynamo models which could constitute a promising combined approach, in which data assimilation could be applied.

  8. Probability boxes on totally preordered spaces for multivariate modelling

    CERN Document Server

    Troffaes, Matthias C M; 10.1016/j.ijar.2011.02.001

    2011-01-01

    A pair of lower and upper cumulative distribution functions, also called probability box or p-box, is among the most popular models used in imprecise probability theory. They arise naturally in expert elicitation, for instance in cases where bounds are specified on the quantiles of a random variable, or when quantiles are specified only at a finite number of points. Many practical and formal results concerning p-boxes already exist in the literature. In this paper, we provide new efficient tools to construct multivariate p-boxes and develop algorithms to draw inferences from them. For this purpose, we formalise and extend the theory of p-boxes using Walley's behavioural theory of imprecise probabilities, and heavily rely on its notion of natural extension and existing results about independence modeling. In particular, we allow p-boxes to be defined on arbitrary totally preordered spaces, hence thereby also admitting multivariate p-boxes via probability bounds over any collection of nested sets. We focus on t...

  9. Total Variation Based Perceptual Image Quality Assessment Modeling

    Directory of Open Access Journals (Sweden)

    Yadong Wu

    2014-01-01

    Full Text Available Visual quality measure is one of the fundamental and important issues to numerous applications of image and video processing. In this paper, based on the assumption that human visual system is sensitive to image structures (edges and image local luminance (light stimulation, we propose a new perceptual image quality assessment (PIQA measure based on total variation (TV model (TVPIQA in spatial domain. The proposed measure compares TVs between a distorted image and its reference image to represent the loss of image structural information. Because of the good performance of TV model in describing edges, the proposed TVPIQA measure can illustrate image structure information very well. In addition, the energy of enclosed regions in a difference image between the reference image and its distorted image is used to measure the missing luminance information which is sensitive to human visual system. Finally, we validate the performance of TVPIQA measure with Cornell-A57, IVC, TID2008, and CSIQ databases and show that TVPIQA measure outperforms recent state-of-the-art image quality assessment measures.

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

    Directory of Open Access Journals (Sweden)

    I. Ermolli

    2012-09-01

    Full Text Available During periods of high solar activity, the Earth receives ≈ 0.1% higher total solar irradiance (TSI than during low activity periods. Variations of the solar spectral irradiance (SSI however, can be larger, with relative changes of 1 to 20% observed in the ultraviolet (UV band, and in excess of 100% in the soft X-ray range. 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. Lack of long and reliable time series of SSI measurements makes the accurate quantification of solar contributions to recent climate change difficult. In particular, the most recent SSI measurements show a larger variability in the UV spectral range and anomalous changes in the visible and near-infrared (NIR bands with respect to those from earlier observations and from models. A number of recent studies based on chemistry-climate model (CCM simulations discuss the effects and implications of these new SSI measurements on the Earth's atmosphere, which may depart from current expectations.

    This paper summarises our current knowledge of SSI variability and its impact on Earth's climate. An interdisciplinary analysis of the topic is given. New comparisons and discussions are presented on the SSI measurements and models available to date, and on the response of the Earth's atmosphere and climate to SSI changes in CCM simulations. In particular, the solar induced differences in atmospheric radiative heating, temperature, ozone, mean zonal winds, and surface signals are investigated in recent simulations using atmospheric models forced with the current lower and upper boundaries of SSI solar cycle estimated variations from the NRLSSI model data and from SORCE/SIM measurements, respectively. Additionally, the reliability of available data is discussed and additional coordinated CCM experiments are proposed.

  11. Electrical equivalent model of intermediate band solar cell using PSpice

    Indian Academy of Sciences (India)

    B Lakehal; Z Dibi; N Lakhdar; A Dendouga

    2015-08-01

    Intermediate band solar cells (IBSCS) is a relatively new solar cell concept. The theoretical conversion efficiency limit for IBSCS is predicted to be 63.2% with blackbody illumination and 65.1% with AM1.5 spectrum, comparable to the theoretical efficiency for optimized triple junction solar cells with efficiencies of 63.8% and 67.0% under blackbody and AM1.5 illumination, respectively. This paper presents a structure of IBSC based on ZnTe:O. The proposed model uses irradiance and temperature as input parameters and the output characteristics of the structure are used as a prototypical example. So, in this work the artificial neural networks (ANNs) and the analog behavior modeling (ABM) of PSpice are implemented in order to model the IBSC. In addition, we have used the bias matrix and the weights matrix obtained by training to establish the IBSCS model on PSPICE simulator. This method represents an advantage by using a small representative database. Therefore, the obtained results of our model can be used in an electrical simulator. Thus, this method can be extended to other solar cells for motivating experimental efforts to realize these promising photovoltaic devices for low cost and high efficiency.

  12. Non-Standard Models, Solar Neutrinos, and Large \\theta_{13}

    CERN Document Server

    Bonventre, R; Klein, J R; Gann, G D Orebi; Seibert, S; Wasalski, O

    2013-01-01

    Solar neutrino experiments have yet to see directly the transition region between matter-enhanced and vacuum oscillations. The transition region is particularly sensitive to models of non-standard neutrino interactions and propagation. We examine several such non-standard models, which predict a lower-energy transition region and a flatter survival probability for the ^{8}B solar neutrinos than the standard large-mixing angle (LMA) model. We find that while some of the non-standard models provide a better fit to the solar neutrino data set, the large measured value of \\theta_{13} and the size of the experimental uncertainties lead to a low statistical significance for these fits. We have also examined whether simple changes to the solar density profile can lead to a flatter ^{8}B survival probability than the LMA prediction, but find that this is not the case for reasonable changes. We conclude that the data in this critical region is still too poor to determine whether any of these models, or LMA, is the bes...

  13. Models for efficient integration of solar energy

    DEFF Research Database (Denmark)

    Bacher, Peder

    . Finally a procedure for identication of a suitable model for the heat dynamics of a building is presented. The applied models are greybox model based on stochastic dierential equations and the identication is carried out with likelihood ratio tests. The models can be used for providing detailed...

  14. The challenges of the models of solar flares

    Science.gov (United States)

    Stepanov, A. V.; Zaitsev, V. V.

    2016-12-01

    The challenges of `standard' model of solar flares motivated by new observations with the spacecrafts and ground-based telescopes are presented. The most important problems are in situ heating of photospheric and chromospheric loop footpoints up to the coronal temperatures without precipitating particle beams accelerated in the corona, and the sunquakes which are unlikely to be explained by the impact of highenergy particles producing hard X-ray emission. There is also the long-standing `number problem' in the physics of solar flares. It is shown that modern observations favored an important role of the electric currents in the energy release processes in the low solar atmosphere. Particle acceleration mechanism in the electric fields driven by the magnetic Rayleigh-Taylor instability in the chromosphere is proposed. The electric current value I ≥ 1010 A, needed for the excitation of super-Dreicer electric fields in the chromosphere is determined. It is shown that both Joule dissipation of the electric currents and the particles accelerated in the chromosphere can be responsible for in situ heating of the low solar atmosphere. Alternative model of the solar flare based on the analogy between the flaring loop and an equivalent electric circuit which is good tool for the electric current diagnostics is presented. Interaction of a current-carrying loop with the partially-ionized plasma of prominence in the context of particle acceleration is considered. The role of plasma radiation mechanism in the sub-THz emission from the chromosphere is discussed.

  15. Mathematical model development for a new solar desalination system (SDS)

    Energy Technology Data Exchange (ETDEWEB)

    Elsafty, A.F. [Arab Academy for Science and Technology and Maritime Transport, Alexandria (Egypt). Dept. of Mechanical and Marine Engineering; Fath, H.E. [Alexandria Univ., Alexandria (Egypt). Dept. of Mechanical Engineering

    2007-07-01

    Desalination, as a non-conventional water resource, has become one of the most promising alternative water sources to address the fresh water shortage in the near future. Desalination technologies are constrained in that they are driven almost entirely by the combustion of fuels which are still of finite supply, pollute the air, and contribute to the risk of global climate change. Solar distillation is preferred to other processes of distillation because of the low operating cost, low maintenance, lack of moving parts, and clean energy offered. The development of solar distillation has demonstrated its suitability for saline water desalination when weather conditions are favorable and when demand is not large. Solar energy in the Arab region is available at relatively high intensity during most of the year. This paper presented a general mathematical model for a newly developed solar still that uses a parabolic reflector-tube absorber desalination technology. A computer program was developed to simulate the still operation and to solve the governing heat and mass transfer action which occurred during the operation. The program was used to study the still production in different cases. The paper provided a description of the mathematical model and discussed the governing equations. It was concluded that unit productivity improved by increasing the solar intensity, ambient temperature, efficiency of reflector material, reflector aperture area and evaporation area. In addition, increasing the wind velocity, saline water depth, condenser emissivity and condenser thickness had only a small effect on the productivity. 3 refs., 1 tab., 14 figs.

  16. Solar-Powered Desalination: A Modelling and Experimental Study

    Science.gov (United States)

    Leblanc, Jimmy; Andrews, John

    2007-10-01

    Water shortage is becoming one of the major problems worldwide. As such, desalination technologies have been implemented to meet growing demands for fresh water. Among the desalination technologies, thermal desalination, including multi stage flash (MSF) and multi effect evaporation (MEE), is the current leading desalination process. Reverse osmosis (RO) is also being increasingly used. Despite technological improvements, thermal desalination and reverse osmosis continue to be intensive fossil-fuel consumers and contribute to increased levels of greenhouse gases. As energy costs rise, thermal desalination by solar energy and/or low cost waste heat is likely to become increasingly attractive. As part of a project investigating the productive use of saline land and the development of sustainable desalination systems, the feasibility of producing potable water from seawater or brackish water using desalination systems powered by renewable energy in the form of low-temperature solar-thermal sources has been studied. A salinity-gradient solar pond and an evacuated tube solar collector system have been used as heat sources. Solar ponds combine solar energy collection with long-term storage and can provide reliable thermal energy at temperature ranges from 50 to 90 °C. A visual basic computer model of the different multi-stage flash desalination processes coupled with a salinity-gradient solar pond was developed to determine which process is preferable in regards to performance and greenhouse impact. The governing mathematical equations are derived from mass balances, heat energy balances, and heat transfer characteristics. Using the results from the modelling, a small-scale solar-powered desalination system, capable of producing up to 500 litres of fresh water per day, was designed and manufactured. This single-stage flash system consists of two main units: the heat supply and storage system and the flash desalination unit. Two different condenser heat exchanger

  17. Extreme total column ozone events and effects on UV solar radiation at Thessaloniki, Greece

    Science.gov (United States)

    Fragkos, K.; Bais, A. F.; Fountoulakis, I.; Balis, D.; Tourpali, K.; Meleti, C.; Zanis, P.

    2016-11-01

    Thirty years of total ozone column (TOC) measurements conducted by a Brewer spectrophotometer, operating in Thessaloniki (40.6°) since March 1982, have been analyzed using the statistical extreme value theory for the identification of extreme TOC events. About 12 % of the total number of days with TOC measurements were identified as extreme-low and ˜15 % as extreme-high events. The influence of the extreme-low events on the annual mean TOC values is up to ˜18 DU, while the extreme-high events show lower impact (up to 12 DU). Removing the extreme events from the time series results in smoother year-to-year variability and reduction of the small long-term linear trend (-0.08 %/year) by a factor of 2. Furthermore, we examined the impact of the extreme events on the noon erythemal irradiance under clear skies, and we provide evidence that even under extreme-low TOC conditions, the UV radiation levels are determined to a great extent by the aerosol optical depth. Although the influence of aerosols is evident during all seasons, for spring and summer, the sensitivity of UV radiation is larger, probably due to the different nature of the aerosols over Thessaloniki during these seasons.

  18. Regression Model to Predict Global Solar Irradiance in Malaysia

    Directory of Open Access Journals (Sweden)

    Hairuniza Ahmed Kutty

    2015-01-01

    Full Text Available A novel regression model is developed to estimate the monthly global solar irradiance in Malaysia. The model is developed based on different available meteorological parameters, including temperature, cloud cover, rain precipitate, relative humidity, wind speed, pressure, and gust speed, by implementing regression analysis. This paper reports on the details of the analysis of the effect of each prediction parameter to identify the parameters that are relevant to estimating global solar irradiance. In addition, the proposed model is compared in terms of the root mean square error (RMSE, mean bias error (MBE, and the coefficient of determination (R2 with other models available from literature studies. Seven models based on single parameters (PM1 to PM7 and five multiple-parameter models (PM7 to PM12 are proposed. The new models perform well, with RMSE ranging from 0.429% to 1.774%, R2 ranging from 0.942 to 0.992, and MBE ranging from −0.1571% to 0.6025%. In general, cloud cover significantly affects the estimation of global solar irradiance. However, cloud cover in Malaysia lacks sufficient influence when included into multiple-parameter models although it performs fairly well in single-parameter prediction models.

  19. Fort Hood Solar Total Energy Project. Volume II. Preliminary design. Part 1. System criteria and design description. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1979-01-01

    This volume documents the preliminary design developed for the Solar Total Energy System to be installed at Fort Hood, Texas. Current system, subsystem, and component designs are described and additional studies which support selection among significant design alternatives are presented. Overall system requirements which form the system design basis are presented. These include program objectives; performance and output load requirements; industrial, statutory, and regulatory standards; and site interface requirements. Material in this section will continue to be issued separately in the Systems Requirements Document and maintained current through revision throughout future phases of the project. Overall system design and detailed subsystem design descriptions are provided. Consideration of operation and maintenance is reflected in discussion of each subsystem design as well as in an integrated overall discussion. Included are the solar collector subsystem; the thermal storage subsystem, the power conversion sybsystem (including electrical generation and distribution); the heating/cooling and domestic hot water subsystems; overall instrumentation and control; and the STES building and physical plant. The design of several subsystems has progressed beyond the preliminary stage; descriptions for such subsystems are therefore provided in more detail than others to provide complete documentation of the work performed. In some cases, preliminary design parameters require specific verificaton in the definitive design phase and are identified in the text. Subsystem descriptions will continue to be issued and revised separately to maintain accuracy during future phases of the project. (WHK)

  20. New Model Atmospheres: Testing the Solar Spectrum in the UV

    CERN Document Server

    Rodríguez-Merino, L H; Bertone, E; Chavez, M; Buzzoni, A

    2007-01-01

    We present preliminary results on the calculation of synthetic spectra obtained with the stellar model atmospheres developed by Cardona, Crivellari, and Simonneau. These new models have been used as input within the SYNTHE series of codes developed by Kurucz. As a first step we have tested if SYNTHE is able to handle these models which go down to log tau(Ross)= -13. We have successfully calculated a synthetic solar spectrum in the wavelength region 2000--4500 A at high resolution (R=522,000). Within this initial test we have found that layers at optical depths with log tau(Ross) < -7 significantly affect the mid-UV properties of a synthetic spectrum computed from a solar model. We anticipate that these new extended models will be a valuable tool for the analysis of UV stellar light arising from the outermost layers of the atmospheres.

  1. New Model Atmospheres: Testing the Solar Spectrum in the UV

    Science.gov (United States)

    Rodríguez-Merino, L. H.; Cardona, O.; Bertone, E.; Chávez, M.; Buzzoni, A.

    2009-03-01

    We present preliminary results on the calculation of synthetic spectra obtained with the stellar model atmospheres developed by Cardona, Crivellari, and Simonneau. These new models have been used as input within the Synthe series of codes developed by Kurucz. As a first step we have tested if Synthe is able to handle these models which go down to log{τ_{Ross}}= -13. We have successfully calculated a synthetic solar spectrum in the wavelength region 2000-4500 Å at high resolution (R=522 000). Within this initial test we have found that layers at optical depths with log{τ_{Ross}} < -7 significantly affect the mid-UV properties of a synthetic spectrum computed from a solar model. We anticipate that these new extended models will be a valuable tool for the analysis of UV stellar light arising from the outermost layers of the atmospheres.

  2. a new analytical modeling method for photovoltaic solar cells based ...

    African Journals Online (AJOL)

    Zieba Falama R, Dadjé A, Djongyang N and Doka S.Y

    2016-05-01

    May 1, 2016 ... The first approach requires taking some measurements once the PV generator is installed. .... At the open circuit voltage, I=0, V=Voc and Iph=Isc: ..... Muzathik3 ” New Approach on Mathematical Modeling of Photovoltaic Solar ...

  3. Improving Perovskite Solar Cells: Insights From a Validated Device Model

    NARCIS (Netherlands)

    Sherkar, Tejas S.; Momblona, Cristina; Gil-Escrig, Lidon; Bolink, Henk J.; Koster, L. Jan Anton

    2017-01-01

    To improve the efficiency of existing perovskite solar cells (PSCs), a detailed understanding of the underlying device physics during their operation is essential. Here, a device model has been developed and validated that describes the operation of PSCs and quantitatively explains the role of conta

  4. Improving Perovskite Solar Cells: Insights From a Validated Device Model

    NARCIS (Netherlands)

    Sherkar, Tejas S.; Momblona, Cristina; Gil-Escrig, Lidon; Bolink, Henk J.; Koster, L. Jan Anton

    2017-01-01

    To improve the efficiency of existing perovskite solar cells (PSCs), a detailed understanding of the underlying device physics during their operation is essential. Here, a device model has been developed and validated that describes the operation of PSCs and quantitatively explains the role of conta

  5. Large scale solar district heating. Evaluation, modelling and designing - Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Heller, A.

    2000-07-01

    The appendices present the following: A) Cad-drawing of the Marstal CSHP design. B) Key values - large-scale solar heating in Denmark. C) Monitoring - a system description. D) WMO-classification of pyranometers (solarimeters). E) The computer simulation model in TRNSYS. F) Selected papers from the author. (EHS)

  6. Total Mass of Ordinary Chondrite Matter Originally Present in the Solar System

    CERN Document Server

    Herndon, J M

    2004-01-01

    Recently, I reported the discovery of a new fundamental relationship of the major elements (Fe, Mg, Si) of chondrites that admits the possibility that ordinary chondrite meteorites are derived from two components, a relatively oxidized and undifferentiated, primitive component and a somewhat differentiated, planetary component, with oxidation state like the highly reduced enstatite chondrites, which I suggested was identical to Mercury's complement of lost elements. Subsequently, on the basis of that relationship, I derived expressions, as a function of the mass of planet Mercury and the mass of its core, to estimate the mass of Mercury's lost elements, the mass of Mercury's alloy and rock protoplanetary core, and the mass of Mercury's gaseous protoplanet. Here, on the basis of the supposition that Mercury's complement of lost elements is in fact identical to the planetary component of ordinary chondrite formation, I estimate, as a function of Mercury's core mass, the total mass of ordinary chondrite matter o...

  7. Adjustable box-wing model for solar radiation pressure impacting GPS satellites

    Science.gov (United States)

    Rodriguez-Solano, C. J.; Hugentobler, U.; Steigenberger, P.

    2012-04-01

    prediction errors. Nevertheless, the models show important differences between orbits at the 1-2 cm level and total accelerations (up to 5×10-9m/s2). The differences are mainly due to the fact that the box-wing model is based on the physical interaction between solar radiation and satellite, while the CODE empirical model is not.

  8. Near infrared spectral and polarization imaging observation of coronal emission lines during the 2008 total solar eclipse

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    During the 2008 total solar eclipse, the coronal emission lines were observed by using optical fibre spectrometric and polarization imaging system in near infrared waveband. The profiles of the coronal emission lines including Fe XIII 10747 , 10798  and He I 10830  were obtained with dispersion of 0.5 /pix. The intensity of Fe XIII 10747  remained unchanged in the two different coronal regions while the intensity of He I 10830  varied considerably in the two coronal locations no matter whether the prominence appeared or not. The coronal polarization images were observed at Fe XI 7892  with a bandpass of 30  in a series of exposure times.

  9. Near infrared spectral and polarization imaging observation of coronal emission lines during the 2008 total solar eclipse

    Institute of Scientific and Technical Information of China (English)

    BAO XingMing; WANG XiaoFan; ZHANG ZhiYong; DENG Jian; HU KeLiang; XUAN WeiJia; LIU YangBing; ZHANG HongQi; DENG YuanYong; WANG DongGuang

    2009-01-01

    During the 2008 total solar eclipse, the coronal emission lines were observed by using optical fibre spectrometric and polarization imaging system in near infrared waveband. The profiles of the coronal emission lines Including Fe ⅩⅢ 10747 A, 10798 A and He 1 10830 A were obtained with dispersion of 0.5 A/pix. The intensity of Fe ⅩⅢ 10747 A remained unchanged In the two different coronal regions while the intensity of He I 10830 A varied considerably in the two coronal locations no matter whether the prominence appeared or not. The coronal polarization images were observed at Fe XI 7892 A with a bandpass of 30 A in a series of exposure times.

  10. Photon absorption models in nanostructured semiconductor solar cells and devices

    CERN Document Server

    Luque, Antonio

    2015-01-01

    This book is intended to be used by materials and device physicists and also solar cells researchers. It models the performance characteristics of nanostructured solar cells and resolves the dynamics of transitions between several levels of these devices. An outstanding insight into the physical behaviour of these devices is provided, which complements experimental work. This therefore allows a better understanding of the results, enabling the development of new experiments and optimization of new devices. It is intended to be accessible to researchers, but also to provide engineering tools w

  11. Model Predictive Load Scheduling Using Solar Power Forecasting

    OpenAIRE

    Habib, Abdulelah H.; Kleissl, Jan; de Callafon, Raymond A.

    2016-01-01

    In this paper a model is developed to solve the on/off scheduling of (non-linear) dynamic electric loads based on predictions of the power delivery of a (standalone) solar power source. Knowledge of variations in the solar power output is used to optimally select the timing and the combinations of a set of given electric loads, where each load has a desired dynamic power profile. The optimization exploits the desired power profiles of the electric loads in terms of dynamic power ramp up/down ...

  12. Modeling and analysis of GPS-TEC low latitude climatology during the 24th solar cycle using empirical orthogonal functions

    Science.gov (United States)

    Dabbakuti, J. R. K. Kumar; Venkata Ratnam, D.

    2017-10-01

    The Total Electron Content (TEC) is an essential component describing the temporal and spatial characteristics of the ionosphere. In this paper, an empirical orthogonal function (EOF) model is constructed by using ground based Global Navigational Satellite System (GNSS) TEC observation data at the Bangalore International GNSS Service (IGS) station (geographic - 13.02° N, 77.57° E; geomagnetic latitude 4.4° N) during an extended period (2009-2016) in the 24th solar cycle. EOF model can be decomposed into base functions and its corresponding coefficients. These decomposed modes well represented the influence of solar and geomagnetic activity towards TEC. The first three EOFs modes constitute about 98% of the total variance of the observed data sets. The Fourier Series Analysis (FSA) is carried out to characterize the solar-cycle, annual and semi-annual dependences by modulating the first three EOF coefficients with solar (F10.7) and geomagnetic (Ap and Dst) indices. The TEC model is validated during daytime and nighttime conditions as well as under different solar activity and geomagnetic conditions. A positive correlation (0.85) of averaged daily GPS-TEC with averaged daily F10.7 strongly supports those time-varying characteristics of the ionosphere features depends on the solar activity. Further, the validity and reliability of EOF model is verified by comparing with the GPS-TEC data, and standard global ionospheric models (International Reference Ionosphere, IRI2016 and Standard Plasmasphere-Ionosphere Model, SPIM). The performances of the standard ionospheric models are marked to be relatively better during High Solar Activity (HSA) periods as compared to the Low Solar Activity (LSA) periods.

  13. Three-Dimensional MHD Modeling of The Solar Corona and Solar Wind: Comparison with The Wang-Sheeley Model

    Science.gov (United States)

    Usmanov, A. V.; Goldstein, M. L.

    2003-01-01

    We present simulation results from a tilted-dipole steady-state MHD model of the solar corona and solar wind and compare the output from our model with the Wang-Sheeley model which relates the divergence rate of magnetic flux tubes near the Sun (inferred from solar magnetograms) to the solar wind speed observed near Earth and at Ulysses. The boundary conditions in our model specified at the coronal base and our simulation region extends out to 10 AU. We assumed that a flux of Alfven waves with amplitude of 35 km per second emanates from the Sun and provides additional heating and acceleration for the coronal outflow in the open field regions. The waves are treated in the WKB approximation. The incorporation of wave acceleration allows us to reproduce the fast wind measurements obtained by Ulysses, while preserving reasonable agreement with plasma densities typically found at the coronal base. We find that our simulation results agree well with Wang and Sheeley's empirical model.

  14. Search for Rapid Changes in the Visible-Light Corona during the 21 June 2001 Total Solar Eclipse

    CERN Document Server

    Rudawy, P; Buczylko, A; Williams, D R; Keenan, F P

    2010-01-01

    Some 8000 images obtained with the SECIS fast-frame CCD camera instrument located at Lusaka, Zambia, during the total eclipse of 21 June 2001 have been analyzed to search for short-period oscillations in intensity that could be a signature of solar coronal heating mechanisms by MHD wave dissipation. Images were taken in white- light and Fe XIV green-line (5303 A) channels over 205 seconds (frame rate 39 s-1), approximately the length of eclipse totality at this location, with a pixel size of four arcseconds square. The data are of considerably better quality than were obtained during the 11 August 1999 total eclipse, observed by us (Rudawy et al.: Astron. Astrophys. 416, 1179, 2004), in that the images are much better exposed and enhancements in the drive system of the heliostat used gave a much improved image stability. Classical Fourier and wavelet techniques have been used to analyze the emission at 29518 locations, of which 10714 had emission at reasonably high levels, searching for periodic fluctuations ...

  15. Modeling washoff of total suspended solids in the tropics.

    Science.gov (United States)

    Le, S H; Chua, L H C; Irvine, K N; Eikaas, H S

    2017-09-15

    Washoff behavior in the tropics is expected to behave differently from temperate areas due to differences in rainfall characteristics. In this study, rainfall, runoff and total suspended solids (TSS) were monitored from 9 catchments distinguished by different types of land use, in Singapore. The catchments ranged in size from 5.7ha to 85.2ha. Over 120 rain events were studied and more than 1000 storm samples were collected and analyzed. Monte Carlo analysis was applied to obtain the best fit values of the washoff model parameters consisting the washoff coefficient c3, washoff exponent c4 and initial mass on surface Bini. The exponent c4 was found to be approximately unity for all the events monitored, in agreement with other studies. The values of c3 and Bini were found to vary between events. Among all the rainfall and runoff characteristics studied, rainfall depth of the current event (d) was found to be the single parameter that significantly influenced the values of c3 and Bini. Contrary to expectations, Bini did not correlate well with antecedent dry period or with rainfall depth of the prior storm event. The results show that the common modeling practice where Bini is assumed to vary with antecedent dry period and previous rainfall depth should be reassessed when applied to catchments in the tropics. ANCOVA analysis showed that land use was not significant, but rather the variation of c3 and Bini with d was found to correlate well with the catchment area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Application of Total Productivity Model within Croatia Airlines

    Directory of Open Access Journals (Sweden)

    Željko Radačić

    2005-09-01

    Full Text Available By defining and selecting adequate factors of the total productivitymodel and by assigning specific relevance of each factor,the initial preconditions for the analysis and monitoring ofthe model application efficiency within the Croatia Airlinesbusiness policy have been established. Since the majority of theanalyzed factors have realized a more intensive growth thanplanned, the business year 2004 can be assessed as the mostsuccessful one in the Croatia Airlines history. Consequently,the difference related to the productivity indicators of the Associationof European Airlines has been reduced, particularly theaircraft productivity with remnant of 5 to 10 percent, and theproductivity of the employees with a remnant of 15 to 20 percent,and the productivity of fuel expressed as quantity at AEAlevel, and expressed as value below that level. Finally, althoughthere is no expressed correlation between the quantitative productivityindicators and business profitability, the highest realizednet profit since the foundation of Croatia Airlines fullysupplements the solid level of the comparison indicators, confirmingits complete readiness and maturity to join the Star Alliance.

  17. Analytical models for total dose ionization effects in MOS devices.

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Phillip Montgomery; Bogdan, Carolyn W.

    2008-08-01

    MOS devices are susceptible to damage by ionizing radiation due to charge buildup in gate, field and SOI buried oxides. Under positive bias holes created in the gate oxide will transport to the Si / SiO{sub 2} interface creating oxide-trapped charge. As a result of hole transport and trapping, hydrogen is liberated in the oxide which can create interface-trapped charge. The trapped charge will affect the threshold voltage and degrade the channel mobility. Neutralization of oxidetrapped charge by electron tunneling from the silicon and by thermal emission can take place over long periods of time. Neutralization of interface-trapped charge is not observed at room temperature. Analytical models are developed that account for the principal effects of total dose in MOS devices under different gate bias. The intent is to obtain closed-form solutions that can be used in circuit simulation. Expressions are derived for the aging effects of very low dose rate radiation over long time periods.

  18. Statistical modeling of total crash frequency at highway intersections

    Directory of Open Access Journals (Sweden)

    Arash M. Roshandeh

    2016-04-01

    Full Text Available Intersection-related crashes are associated with high proportion of accidents involving drivers, occupants, pedestrians, and cyclists. In general, the purpose of intersection safety analysis is to determine the impact of safety-related variables on pedestrians, cyclists and vehicles, so as to facilitate the design of effective and efficient countermeasure strategies to improve safety at intersections. This study investigates the effects of traffic, environmental, intersection geometric and pavement-related characteristics on total crash frequencies at intersections. A random-parameter Poisson model was used with crash data from 357 signalized intersections in Chicago from 2004 to 2010. The results indicate that out of the identified factors, evening peak period traffic volume, pavement condition, and unlighted intersections have the greatest effects on crash frequencies. Overall, the results seek to suggest that, in order to improve effective highway-related safety countermeasures at intersections, significant attention must be focused on ensuring that pavements are adequately maintained and intersections should be well lighted. It needs to be mentioned that, projects could be implemented at and around the study intersections during the study period (7 years, which could affect the crash frequency over the time. This is an important variable which could be a part of the future studies to investigate the impacts of safety-related works at intersections and their marginal effects on crash frequency at signalized intersections.

  19. Switching the light off: A break in photosynthesis and sap flow of forest trees under total solar eclipse

    Directory of Open Access Journals (Sweden)

    Karl-Heinz Häberle

    2001-05-01

    Full Text Available In mature trees of Picea abies, Fagus sylvatica and Quercus robur, photosynthesis and transpiration were assessed in response to the total solar eclipse that occurred in Central Europe during the late morning hours of August 11, 1999, a day with changing cloudiness. Measurements were conducted at three forest sites located in the totality zone and the 99% area of the eclipse within a radius of about 100 km around the city of Munich (southern Germany. The eclipse lasting 164 minutes lowered the photosynthetic photon flux density (PPFD to about 1 μmol m-2 s-1 during the 2-minute totality period, when the sky was clear. During totality, photosynthesis was reduced to an extent that allowed CO2 release to dominate the gas exchange of leaves. Effects on transpiration were less pronounced as the totality was apparently too short to induce distinct stomatal closure in response to low PPFD. Transpiration was strongly reduced, however, by increased air humidity and wet leaf surfaces during sporadic rain showers which preceded or succeeded the eclipse during the same day, whereas low PPFD through intermittent cloudiness during rain only moderately reduced photosynthesis. Although transpiration was lowered to a minor extent only by the eclipse, the latter affected the water transport through the whole tree, as reflected in a decline in the sap flow rate through the basal stem part with a time delay depending on the species. Nevertheless, trees responded in a synchronous way, regardless of the site, species or the percent degree of the eclipse.

  20. ANALYSIS AND MODELING OF SOLAR EVAPORATOR-COLLECTOR

    Directory of Open Access Journals (Sweden)

    Zakaria Mohd. Amin

    2015-11-01

    Full Text Available Solar energy is considered a sustainable resource that poses little to no harmful effects on the environment. The performance of a solar system depends to a great extent on the collector used for the conversion of solar radiant energy to thermal energy. A solar evaporator-collector (SEC is basically an unglazed flat plate collector where refrigerants, such as R134a is used as the working fluid. As the operating temperature of the SEC is very low, it utilizes both solar irradiation and ambient energy leading to a much higher efficiency than the conventional collectors. This capability of SECs to utilize ambient energy also enables the system to operate at night. This type of collector can be locally made and is relatively much cheaper than the conventional collector.   At the National University of Singapore, the evaporator-collector was integrated to a heat pump and the performance was investigated for several thermal applications: (i water heating, (ii drying and (iii desalination. A 2-dimensional transient mathematical model of this system was developed and validated by experimental data. The present study provides a comprehensive study of performance. KEYWORDS: heat pump; evaporator-collector.