Science.gov

Sample records for solar radiation model

  1. Estimating solar radiation for plant simulation models

    NASA Technical Reports Server (NTRS)

    Hodges, T.; French, V.; Leduc, S.

    1985-01-01

    Five algorithms producing daily solar radiation surrogates using daily temperatures and rainfall were evaluated using measured solar radiation data for seven U.S. locations. The algorithms were compared both in terms of accuracy of daily solar radiation estimates and terms of response when used in a plant growth simulation model (CERES-wheat). Requirements for accuracy of solar radiation for plant growth simulation models are discussed. One algorithm is recommended as being best suited for use in these models when neither measured nor satellite estimated solar radiation values are available.

  2. Cavity radiation model for solar central receivers

    SciTech Connect

    Lipps, F.W.

    1981-01-01

    The Energy Laboratory of the University of Houston has developed a computer simulation program called CREAM (i.e., Cavity Radiations Exchange Analysis Model) for application to the solar central receiver system. The zone generating capability of CREAM has been used in several solar re-powering studies. CREAM contains a geometric configuration factor generator based on Nusselt's method. A formulation of Nusselt's method provides support for the FORTRAN subroutine NUSSELT. Numerical results from NUSSELT are compared to analytic values and values from Sparrow's method. Sparrow's method is based on a double contour integral and its reduction to a single integral which is approximated by Guassian methods. Nusselt's method is adequate for the intended engineering applications, but Sparrow's method is found to be an order of magnitude more efficient in many situations.

  3. A rapid radiative transfer model for reflection of solar radiation

    NASA Technical Reports Server (NTRS)

    Xiang, X.; Smith, E. A.; Justus, C. G.

    1994-01-01

    A rapid analytical radiative transfer model for reflection of solar radiation in plane-parallel atmospheres is developed based on the Sobolev approach and the delta function transformation technique. A distinct advantage of this model over alternative two-stream solutions is that in addition to yielding the irradiance components, which turn out to be mathematically equivalent to the delta-Eddington approximation, the radiance field can also be expanded in a mathematically consistent fashion. Tests with the model against a more precise multistream discrete ordinate model over a wide range of input parameters demonstrate that the new approximate method typically produces average radiance differences of less than 5%, with worst average differences of approximately 10%-15%. By the same token, the computational speed of the new model is some tens to thousands times faster than that of the more precise model when its stream resolution is set to generate precise calculations.

  4. General cloud cover modifier for clear sky solar radiation models

    NASA Astrophysics Data System (ADS)

    Myers, Daryl R.

    2007-09-01

    Worldwide lack of comprehensive measured solar radiation resource data for solar system design is well known. Several simple clear sky solar radiation models for computing hourly direct, diffuse and global hemispherical solar radiation have been developed over the past 25 years. The simple model of Richard Bird, Iqbal's parameterization C, and Gueymard's REST model are popular for estimating maximum hourly solar resources. We describe a simple polynomial in cloud cover (octa) modifier for these models that produces realistic time series of hourly solar radiation data representative of naturally occurring solar radiation conditions under all sky conditions. Surface cloud cover observations (Integrated Surface Hourly Data) from the National Climatic Data Center are the only additional (hourly) input data to model total hemispherical solar radiation under all sky conditions. Performance was evaluated using three years of hourly solar radiation data from 31 sites in the 1961-1990 National Solar Radiation Data Base. Mean bias errors range from - 10% to -20%, and are clear sky model dependant. Root mean square error of about 40%, are also dependent upon the particular model used and the uncertainty in the specific clear sky model inputs and lack of information on cloud type and spatial distributions.

  5. MODELING ACUTE EXPOSURE TO SOLAR RADIATION

    EPA Science Inventory

    One of the major technical challenges in calculating solar flux on the human form has been the complexity of the surface geometry (i.e., the surface normal vis a vis the incident radiation). The American Cancer Society reports that over 80% of skin cancers occur on the face, he...

  6. Measurement and modelling of spectral solar radiation.

    NASA Astrophysics Data System (ADS)

    Dehne, K.; Czeplak, G.

    1996-03-01

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

  7. Absorption of Solar Radiation by Clouds: Observations Versus Models

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Zhang, M. H.; Minnis, P.; Corsetti, L.; Dutton, E. G.; Forgan, B. W.; Garber, D. P.; Gates, W. L.; Hack, J. J.; Harrison, E. F.; Jing, X.; Kiehl, J. T.; Long, C. N.; Morcrette, J.-J.; Potter, G. L.; Ramanathan, V.; Subasilar, B.; Whitlock, C. H.; Young, D. F.; Zhou, Y.

    1995-01-01

    There has been a long history of unexplained anomalous absorption of solar radiation by clouds. Collocated satellite and surface measurements of solar radiation at five geographically diverse locations showed significant solar absorption by clouds, resulting in about 25 watts per square meter more global-mean absorption by the cloudy atmosphere than predicted by theoretical models. It has often been suggested that tropospheric aerosols could increase cloud absorption. But these aerosols are temporally and spatially heterogeneous, whereas the observed cloud absorption is remarkably invariant with respect to season and location. Although its physical cause is unknown, enhanced cloud absorption substantially alters our understanding of the atmosphere's energy budget.

  8. Improved Solar-Radiation-Pressure Models for GPS Satellites

    NASA Technical Reports Server (NTRS)

    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.

  9. Interplanetary Radiation and Internal Charging Environment Models for Solar Sails

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Altstatt, Richard L.; NeegaardParker, Linda

    2005-01-01

    A Solar Sail Radiation Environment (SSRE) model has been developed for defining charged particle environments over an energy range from 0.01 keV to 1 MeV for hydrogen ions, helium ions, and electrons. The SSRE model provides the free field charged particle environment required for characterizing energy deposition per unit mass, charge deposition, and dose rate dependent conductivity processes required to evaluate radiation dose and internal (bulk) charging processes in the solar sail membrane in interplanetary space. Solar wind and energetic particle measurements from instruments aboard the Ulysses spacecraft in a solar, near-polar orbit provide the particle data over a range of heliospheric latitudes used to derive the environment that can be used for radiation and charging environments for both high inclination 0.5 AU Solar Polar Imager mission and the 1.0 AU L1 solar missions. This paper describes the techniques used to model comprehensive electron, proton, and helium spectra over the range of particle energies of significance to energy and charge deposition in thin (less than 25 micrometers) solar sail materials.

  10. Curve fitting methods for solar radiation data modeling

    SciTech Connect

    Karim, Samsul Ariffin Abdul E-mail: balbir@petronas.com.my; Singh, Balbir Singh Mahinder E-mail: balbir@petronas.com.my

    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.

  11. Curve fitting methods for solar radiation data modeling

    NASA Astrophysics Data System (ADS)

    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.

  12. A hybrid modelling approach for assessing solar radiation

    NASA Astrophysics Data System (ADS)

    Shamim, M. A.; Bray, M.; Remesan, R.; Han, D.

    2015-11-01

    A hybrid technique for solar radiation estimation, a core part of hydrological cycle, is presented in this study which parameterises the cloud cover effect (cloud cover index) not just from the geostationary satellites but also the PSU/NCAR's Mesoscale Modelling system (MM5) model. This, together with output from a global clear sky radiation model and observed datasets of temperature and precipitation are used as inputs within the Gamma test (GT) environment for the development of nonlinear models for global solar radiation estimation. The study also explores the ability of Gamma test to determine the optimum input combination and data length selection. Artificial neural network- and local linear regression-based nonlinear techniques are used to test the proposed methodology, and the results have shown a high degree of correlation between the observed and estimated values. It is believed that this study will initiate further exploration of GT for improving informed data and model selection.

  13. Highly physical penumbra solar radiation pressure modeling with atmospheric effects

    NASA Astrophysics Data System (ADS)

    Robertson, Robert; Flury, Jakob; Bandikova, Tamara; Schilling, Manuel

    2015-10-01

    We present a new method for highly physical solar radiation pressure (SRP) modeling in Earth's penumbra. The fundamental geometry and approach mirrors past work, where the solar radiation field is modeled using a number of light rays, rather than treating the Sun as a single point source. However, we aim to clarify this approach, simplify its implementation, and model previously overlooked factors. The complex geometries involved in modeling penumbra solar radiation fields are described in a more intuitive and complete way to simplify implementation. Atmospheric effects are tabulated to significantly reduce computational cost. We present new, more efficient and accurate approaches to modeling atmospheric effects which allow us to consider the high spatial and temporal variability in lower atmospheric conditions. Modeled penumbra SRP accelerations for the Gravity Recovery and Climate Experiment (GRACE) satellites are compared to the sub-nm/s2 precision GRACE accelerometer data. Comparisons to accelerometer data and a traditional penumbra SRP model illustrate the improved accuracy which our methods provide. Sensitivity analyses illustrate the significance of various atmospheric parameters and modeled effects on penumbra SRP. While this model is more complex than a traditional penumbra SRP model, we demonstrate its utility and propose that a highly physical model which considers atmospheric effects should be the basis for any simplified approach to penumbra SRP modeling.

  14. Solar neutrinos and the influence of radiative opacities on solar models

    NASA Technical Reports Server (NTRS)

    Carson, T. R.; Ezer, D.; Stothers, R.

    1973-01-01

    Use of new radiative opacities based on the hot Thomas-Fermi model of the atom yields a predicted solar neutrino flux which is still considerably larger than the flux observed in Davis's Cl-37 experiment.

  15. Simple solar radiation modelling for different cloud types and climatologies

    NASA Astrophysics Data System (ADS)

    Badescu, Viorel; Dumitrescu, Alexandru

    2016-04-01

    The instantaneous Cloud Fraction Coverage (iCFC) and Cloud Type (iCTY) products of the Climate Monitoring Satellite Application Facility are used to develop simple relationships between solar global irradiance and cloud amount and types. Radiometric measurements from five Romanian weather stations are used. Solar radiation relationships are proposed for clear sky, overcast sky and cloudy sky. A procedure to average the iCTY data is proposed, and eight classes of averaged iCTY values are considered. Two procedures are used to define the overcast sky and two cloudy sky solar radiation models are considered. Overcast skies consisting of stratiform clouds (CTY classes 8 to 14) are the most challenging when solar radiation modelling is considered. The overcast sky models have lower accuracy at high irradiance values. The best cloudy sky model has relative root mean square error values ranging between 17.6 % (for CTY classes 1 to 4) and 67.6 % (for CTY classes 12 to 14). For most CTY classes, the model performs worse at intermediate irradiance values.

  16. Modelling of aircrew radiation exposure during solar particle events

    NASA Astrophysics Data System (ADS)

    Al Anid, Hani Khaled

    show a very different response during anisotropic events, leading to variations in aircrew radiation doses that may be significant for dose assessment. To estimate the additional exposure due to solar flares, a model was developed using a Monte-Carlo radiation transport code, MCNPX. The model transports an extrapolated particle spectrum based on satellite measurements through the atmosphere using the MCNPX analysis. This code produces the estimated flux at a specific altitude where radiation dose conversion coefficients are applied to convert the particle flux into effective and ambient dose-equivalent rates. A cut-off rigidity model accounts for the shielding effects of the Earth's magnetic field. Comparisons were made between the model predictions and actual flight measurements taken with various types of instruments used to measure the mixed radiation field during Ground Level Enhancements 60 and 65. An anisotropy analysis that uses neutron monitor responses and the pitch angle distribution of energetic solar particles was used to identify particle anisotropy for a solar event in December 2006. In anticipation of future commercial use, a computer code has been developed to implement the radiation dose assessment model for routine analysis. Keywords: Radiation Dosimetry, Radiation Protection, Space Physics.

  17. Numerical model of solar dynamic radiator for parametric analysis

    NASA Technical Reports Server (NTRS)

    Rhatigan, Jennifer L.

    1989-01-01

    Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. The SD module rejects waste heat from the power conversion cycle to space through a pumped-loop, multi-panel, deployable radiator. The baseline radiator configuration was defined during the Space Station conceptual design phase and is a function of the state point and heat rejection requirements of the power conversion unit. Requirements determined by the overall station design such as mass, system redundancy, micrometeoroid and space debris impact survivability, launch packaging, costs, and thermal and structural interaction with other station components have also been design drivers for the radiator configuration. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations. A brief description and discussion of the numerical model, it's capabilities and limitations, and results of the parametric studies performed is presented.

  18. Visual-SOLAR: Modeling and Visualization of Solar Radiation Potential on Individual Building Rooftops

    Energy Science and Technology Software Center (ESTSC)

    2013-05-01

    We have developed a modeling framework for estimating solar radiation potentials on individual building rooftops that is suitable for utility-scale applications as well as building-specific applications. The framework uses light detection and ranging (LIDAR) data at approximately 1-meter horizontal resolution and 0.3-meter vertical resolution as input for modeling a large number of buildings quickly. One of the strengths of this framework is the ability to parallelize its implementation. Furthermore, the framework accounts for building specificmore » characteristics, such as roof slope, roof aspect, and shadowing effects, that are critical to roof-mounted photovoltaic system. The resulting data has helped us to identify the so-called "solar panel sweet spots" on individual building rooftops and obtain accurate statistics of the variation in solar radiation as a function of time of year and geographical location.« less

  19. Visual-SOLAR: Modeling and Visualization of Solar Radiation Potential on Individual Building Rooftops

    SciTech Connect

    2013-05-01

    We have developed a modeling framework for estimating solar radiation potentials on individual building rooftops that is suitable for utility-scale applications as well as building-specific applications. The framework uses light detection and ranging (LIDAR) data at approximately 1-meter horizontal resolution and 0.3-meter vertical resolution as input for modeling a large number of buildings quickly. One of the strengths of this framework is the ability to parallelize its implementation. Furthermore, the framework accounts for building specific characteristics, such as roof slope, roof aspect, and shadowing effects, that are critical to roof-mounted photovoltaic system. The resulting data has helped us to identify the so-called "solar panel sweet spots" on individual building rooftops and obtain accurate statistics of the variation in solar radiation as a function of time of year and geographical location.

  20. A fast all-sky radiative transfer model and its implications for solar energy research

    NASA Astrophysics Data System (ADS)

    Xie, Y.; Sengupta, M.

    2015-12-01

    Radiative transfer models simulating broadband solar radiation, e.g. Rapid Radiation Transfer Model (RRTM) and its GCM applications, have been widely used by atmospheric scientists to model solar resource for various energy applications such as operational forecasting. Due to the complexity of solving the radiative transfer equation, simulating solar radiation under cloudy conditions can be extremely time consuming though many approximations, e.g. two-stream approach and delta-M truncation scheme, have been utilized. To provide a new option to approximate solar radiation, we developed a Fast All-sky Radiation Model for Solar applications (FARMS) using simulated cloud transmittance and reflectance from 16-stream RRTM model runs. The solar irradiances at the land surface were simulated by combining parameterized cloud properties with a fast clear-sky radiative transfer model. Using solar radiation measurements from the US Department of Energy's Atmospheric Radiation Measurement (ARM) central facility in Oklahoma as a benchmark against the model simulations, we were able to demonstrate that the accuracy of FARMS was comparable to the two-stream approach. However, FARMS is much more efficient since it does not explicitly solve the radiative transfer equation for each individual cloud condition. We further explored the use of FARMS to promote solar resource assessment and forecasting research through the increased ability to accommodate higher spatial and temporal resolution calculations for the next generation of satellite and numerical weather prediction (NWP) models.

  1. ESTIMATING SOLAR RADIATION EXPOSURE IN WETLANDS USING RADIATION MODELS, FIELD DATA, AND GEOGRAPHIC INFORMATION SYSTEMS

    EPA Science Inventory

    This seminar will describe development of methods for the estimation of solar radiation doses in wetlands. The methodology presents a novel approach to incorporating aspects of solar radiation dosimetry that have historically received limited attention. These include effects of a...

  2. Regional scale evaluation of a meteosat second generation solar radiation product for evapotranspiration modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solar radiation plays a key role in the Earth’s energy balance and is used as an essential input data in radiation-based evapotranspiration (ET) models. Accurate gridded solar radiation data at high spatial and temporal resolution are needed to retrieve ET over large domains. In this work we present...

  3. Improving solar radiation forecasts from Eta/CPTEC model using statistical post-processing

    NASA Astrophysics Data System (ADS)

    Guarnieri, R. A.; Pereira, E. B.; Chou, S. C.

    Solar radiation forecasts are mainly demanded by the energy sector besides other applications Accurate short-term forecasts of solar energy resources are required for management of co-generation systems and energy dispatch in transmission lines Mesoscale weather forecast models usually have radiation parameterization codes since solar radiation is the main energy source for atmospheric processes The Eta model running operationally in the Brazilian Center of Weather Forecast and Climate Studies CPTEC INPE is a mesoscale model with 40 km horizontal resolution This model has outputs for many meteorological variables including solar radiation incidence on ground These radiation forecasts are nevertheless greatly overestimated As an attempt to improve the forecasts of solar energy resources using Eta model statistical post-processing models or refining models were used Multiple linear regression MLR models were adjusted and artificial neural networks ANN were trained using a statistically selected group of 7 variables predicted by the Eta model not including the Eta solar radiation forecast itself This group of variables expresses the future weather and surface conditions Theoretical solar radiation amount on the top of atmosphere TOA was calculated and used as another input Solar radiation measurements from piranometers Kipp Zonen CM-21 installed on two ground-stations of the SONDA Project were used as the targets to be simulated throughout the adjustment training of the models These measurements were also used

  4. Verification of Mars solar radiation model based on Mars Pathfinder data

    SciTech Connect

    Appelbaum, J.; Segalov, T.; Jenkins, P.P.; Landis, G.A.; Baraona, C.R.

    1997-12-31

    The solar radiation model for the Martian surface was developed based on the images taken by the two Viking Landers VL1 and VL2 cameras, and calculation of the solar flux function. This model was used for the design of the Pathfinder`s photovoltaic arrays. The Pathfinder is equipped with various instruments capable of measuring data from which solar radiation quantities may be derived. In the present study the authors use data of the Lander and Rover, and perform correlation calculation to the solar radiation model. This study shows that the solar radiation model predicts with good accuracy the solar radiation on the Martian surface for horizontal photovoltaic arrays and for an optical depth of 0.5 of the Martian atmosphere.

  5. Daily radiation model for use in the simulation of passive solar buildings

    SciTech Connect

    Sillman, S.; Wortman, D.

    1981-04-01

    A model is presented to characterize solar radiation with just three input parameters for each day. This compressed daily radiation data may be used in place of hourly data in simulations of passive solar buildings. This method is tested with the SUNCAT passive simulation. Global horizontal and direct normal radiation data are input using the compressed daily form instead of by hour. Simulation results are found to be comparable to results based on hourly radiation data.

  6. Solar radiation resource assessment

    SciTech Connect

    Not Available

    1990-11-01

    The bulletin discusses the following: introduction; Why is solar radiation resource assessment important Understanding the basics; the solar radiation resource assessment project; and future activities.

  7. CODE's new solar radiation pressure model for GNSS orbit determination

    NASA Astrophysics Data System (ADS)

    Arnold, D.; Meindl, M.; Beutler, G.; Dach, R.; Schaer, S.; Lutz, S.; Prange, L.; Sośnica, K.; Mervart, L.; Jäggi, A.

    2015-08-01

    The Empirical CODE Orbit Model (ECOM) of the Center for Orbit Determination in Europe (CODE), which was developed in the early 1990s, is widely used in the International GNSS Service (IGS) community. For a rather long time, spurious spectral lines are known to exist in geophysical parameters, in particular in the Earth Rotation Parameters (ERPs) and in the estimated geocenter coordinates, which could recently be attributed to the ECOM. These effects grew creepingly with the increasing influence of the GLONASS system in recent years in the CODE analysis, which is based on a rigorous combination of GPS and GLONASS since May 2003. In a first step we show that the problems associated with the ECOM are to the largest extent caused by the GLONASS, which was reaching full deployment by the end of 2011. GPS-only, GLONASS-only, and combined GPS/GLONASS solutions using the observations in the years 2009-2011 of a global network of 92 combined GPS/GLONASS receivers were analyzed for this purpose. In a second step we review direct solar radiation pressure (SRP) models for GNSS satellites. We demonstrate that only even-order short-period harmonic perturbations acting along the direction Sun-satellite occur for GPS and GLONASS satellites, and only odd-order perturbations acting along the direction perpendicular to both, the vector Sun-satellite and the spacecraft's solar panel axis. Based on this insight we assess in the third step the performance of four candidate orbit models for the future ECOM. The geocenter coordinates, the ERP differences w. r. t. the IERS 08 C04 series of ERPs, the misclosures for the midnight epochs of the daily orbital arcs, and scale parameters of Helmert transformations for station coordinates serve as quality criteria. The old and updated ECOM are validated in addition with satellite laser ranging (SLR) observations and by comparing the orbits to those of the IGS and other analysis centers. Based on all tests, we present a new extended ECOM which

  8. Solar cell radiation handbook

    NASA Technical Reports Server (NTRS)

    Tada, H. Y.; Carter, J. R., Jr.

    1977-01-01

    Solar cell theory cells are manufactured, and how they are modeled mathematically is reviewed. The interaction of energetic charged particle radiation with solar cells is discussed in detail and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Finally, an extensive body of data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence is presented.

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

    SciTech Connect

    Rich, P.M.; Hetrick, W.A.; Saving, S.C.

    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.

  10. Solar cell radiation handbook

    SciTech Connect

    Tada, H.Y.; Carter, J.R. Jr.; Anspaugh, B.E.

    1982-11-01

    The handbook to predict the degradation of solar cell electrical performance in any given space radiation environment is presented. Solar cell theory, cell manufacturing and how they are modeled mathematically are described. The interaction of energetic charged particles radiation with solar cells is discussed and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence are presented.

  11. Solar cell radiation handbook

    NASA Technical Reports Server (NTRS)

    Tada, H. Y.; Carter, J. R., Jr.; Anspaugh, B. E.; Downing, R. G.

    1982-01-01

    The handbook to predict the degradation of solar cell electrical performance in any given space radiation environment is presented. Solar cell theory, cell manufacturing and how they are modeled mathematically are described. The interaction of energetic charged particles radiation with solar cells is discussed and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence are presented.

  12. New empirically-derived solar radiation pressure model for GPS satellites

    NASA Technical Reports Server (NTRS)

    Bar-Sever, Y.; Kuang, D.

    2003-01-01

    Solar radiation pressure force is the second largest perturbation acting on GPS satellites, after the gravitational attraction from the Earth, Sun, and Moon. It is the largest error source in the modeling of GPS orbital dynamics.

  13. Small-scale solar radiation forecasting using ARMA and nonlinear autoregressive neural network models

    NASA Astrophysics Data System (ADS)

    Benmouiza, Khalil; Cheknane, Ali

    2016-05-01

    This paper aims to introduce an approach for multi-hour forecasting (915 h ahead) of hourly global horizontal solar radiation time series and forecasting of a small-scale solar radiation database (30- and 1-s scales) for a period of 1 day (47,000 s ahead) using commonly and available measured meteorological solar radiation. Three methods are considered in this study. First, autoregressive-moving-average (ARMA) model is used to predict future values of the global solar radiation time series. However, because of the non-stationarity of solar radiation time series, a phase of detrending is needed to stationarize the irradiation data; a 6-degree polynomial model is found to be the most stationary one. Secondly, due to the nonlinearity presented in solar radiation time series, a nonlinear autoregressive (NAR) neural network model is used for prediction purposes. Taking into account the advantages of both models, the goodness of ARMA for linear problems and NAR for nonlinear problems, a hybrid method combining ARMA and NAR is introduced to produce better results. The validation process for the site of Ghardaia in Algaria shows that the hybrid model gives a normalized root mean square error (NRMSE) equals to 0.2034 compared to a NRMSE equal to 0.2634 for NAR model and 0.3241 for ARMA model.

  14. New empirically-derived solar radiation pressure model for GPS satellites

    NASA Astrophysics Data System (ADS)

    Bar-Sever, Y.; Kuang, D.

    2003-04-01

    We derive a new and improved GPS solar pressure model by estimating model parameters using least square approximation to four and a half years of GPS precise orbit data. The new solar radiation model for Block IIR satellites provides 90% improvement over to the best pre-launch model, as measured by orbit fits and orbit prediction quality. The new model of Block II/IIA realizes a more modest improvement of the previous JPL empirical model. The empirical model is constructed as a set of Fourier functions of the Earth-Probe-Sun angle, to represent the solar radiation pressure forces in the coordinate system tied to the nominal solar panel surface orientation. The model derivation reveals a number of systematic patterns, some of which can be explained in terms of properties of the GPS attitude control system, and some are yet to be explained. Finally, we will discuss the overall orbit determination improvements using the new models.

  15. A solar radiation model for use in climate studies

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah

    1992-01-01

    A solar radiation routine is developed for use in climate studies that includes absorption and scattering due to ozone, water vapor, oxygen, carbon dioxide, clouds, and aerosols. Rayleigh scattering is also included. Broadband parameterization is used to compute the absorption by water vapor in a clear atmosphere, and the k-distribution method is applied to compute fluxes in a scattering atmosphere. The reflectivity and transmissivity of a scattering layer are computed analytically using the delta-four-stream discrete-ordinate approximation. The two-stream adding method is then applied to compute fluxes for a composite of clear and scattering layers. Compared to the results of high spectral resolution and detailed multiple-scattering calculations, fluxes and heating rate are accurately computed to within a few percent. The high accuracy of the flux and heating-rate calculations is achieved with a reasonable amount of computing time. With the UV and visible region grouped into four bands, this solar radiation routine is useful not only for climate studies but also for studies on photolysis in the upper atmosphere and photosynthesis in the biosphere.

  16. A Temperature-Based Model for Estimating Monthly Average Daily Global Solar Radiation in China

    PubMed Central

    Li, Huashan; Cao, Fei; Wang, Xianlong; Ma, Weibin

    2014-01-01

    Since air temperature records are readily available around the world, the models based on air temperature for estimating solar radiation have been widely accepted. In this paper, a new model based on Hargreaves and Samani (HS) method for estimating monthly average daily global solar radiation is proposed. With statistical error tests, the performance of the new model is validated by comparing with the HS model and its two modifications (Samani model and Chen model) against the measured data at 65 meteorological stations in China. Results show that the new model is more accurate and robust than the HS, Samani, and Chen models in all climatic regions, especially in the humid regions. Hence, the new model can be recommended for estimating solar radiation in areas where only air temperature data are available in China. PMID:24605046

  17. Solar radiation in Lebanon

    NASA Astrophysics Data System (ADS)

    Sfeir, A. A.

    1981-01-01

    Solar radiation data for two sites in Lebanon are analyzed and presented in a form suitable for their use by practicing engineers. Correlations of the Angstrom-Page type for daily and monthly data are developed. Probability density functions for daily values of global radiation for each month are compared with the results of Liu and Jordan. The atmospheric model developed by Cole and extended by Barbaro et al. is found to predict monthly average global radiation with acceptable accuracy and is therefore recommended for extending the data at other sites of the country.

  18. Solar radiation as a global driver of hillslope asymmetry: Insights from an ecogeomorphic landscape evolution model

    NASA Astrophysics Data System (ADS)

    Yetemen, Omer; Istanbulluoglu, Erkan; Duvall, Alison R.

    2015-12-01

    Observations at the field, catchment, and continental scales across a range of arid and semiarid climates and latitudes reveal aspect-controlled patterns in soil properties, vegetation types, ecohydrologic fluxes, and hillslope morphology. Although the global distribution of solar radiation on earth's surface and its implications on vegetation dynamics are well documented, we know little about how variation of solar radiation across latitudes influence landscape evolution and resulting geomorphic difference. Here, we used a landscape evolution model that couples the continuity equations for water, sediment, and aboveground vegetation biomass at each model element in order to explore the controls of latitude and mean annual precipitation (MAP) on the development of hillslope asymmetry (HA). In our model, asymmetric hillslopes emerged from the competition between soil creep and vegetation-modulated fluvial transport, driven by spatial distribution of solar radiation. Latitude was a primary driver of HA because of its effects on the global distribution of solar radiation. In the Northern Hemisphere, north-facing slopes (NFS), which support more vegetation cover and have lower transport efficiency, get steeper toward the North Pole while south-facing slopes (SFS) get gentler. In the Southern Hemisphere, the patterns are reversed and SFS get steeper toward the South Pole. For any given latitude, MAP is found to have minor control on HA. Our results underscore the potential influence of solar radiation as a global control on the development of asymmetric hillslopes in fluvial landscapes.

  19. Initial conditions for radiation analysis: models of galactic cosmic rays and solar particle events

    NASA Astrophysics Data System (ADS)

    Nymmik, R. A.

    During interplanetary missions the radiation conditions are determined by fluxes of Galactic Cosmic Ray (GCR) particles and Solar Energetic Particles (SEP). The particle fluxes of these two high-energy radiation components differ fundamentally in energy spectra and have the opposite dependence on solar activity level. One of the key issues, associated with estimating flight conditions for missions to the Moon, various asteroids and Mars, is the relative balance between GCR and SCR, depending on the level of solar activity and the distance to the Sun for both open space conditions and conditions inside the spacecraft. This task can be solved with sufficient accuracy only when using such particle flux models (of the above mentioned radiation sources), which are based on unified parameters, describing the current solar activity level. Such models, employing smoothed Wolf numbers as the initial parameter, were developed at SINP MSU. These models are - the semi-empirical model of GCR fluxes, which has currently been approved as an international standard (ISO 15390), and the probabilistic model of SEP particle fluxes, which is currently under discussion as a draft international standard (ISO DRAFT 15391). The report presents a survey of experimental data on GCR and SEP fluxes in interplanetary space at various solar activity levels, and an analysis of the reliability and completeness of data on these fluxes, provided by various calculation models.

  20. A semi-empirical model for estimating surface solar radiation from satellite data

    NASA Astrophysics Data System (ADS)

    Janjai, Serm; Pattarapanitchai, Somjet; Wattan, Rungrat; Masiri, Itsara; Buntoung, Sumaman; Promsen, Worrapass; Tohsing, Korntip

    2013-05-01

    This paper presents a semi-empirical model for estimating surface solar radiation from satellite data for a tropical environment. The model expresses solar irradiance as a semi-empirical function of cloud index, aerosol optical depth, precipitable water, total column ozone and air mass. The cloud index data were derived from MTSAT-1R satellite, whereas the aerosol optical depth data were obtained from MODIS/Terra satellite. The total column ozone data were derived from OMI/AURA satellite and the precipitable water data were obtained from NCEP/NCAR. A five year period (2006-2010) of these data and global solar irradiance measured at four sites in Thailand namely, Chiang Mai (18.78 °N, 98.98 °E), Nakhon Pathom (13.82 °N, 100.04 °E), Ubon Ratchathani (15.25 °N, 104.87 °E) and Songkhla (7.20 °N, 100.60 °E), were used to derive the coefficients of the model. To evaluate its performance, the model was used to calculate solar radiation at four sites in Thailand namely, Phisanulok (16.93 °N, 100.24 °E), Kanchanaburi (14.02 °N, 99.54 °E), Nongkhai (17.87 °N, 102.72 °E) and Surat Thani (9.13 °N, 99.15 °E) and the results were compared with solar radiation measured at these sites. It was found that the root mean square difference (RMSD) between measured and calculated values of hourly solar radiation was in the range of 25.5-29.4%. The RMSD is reduced to 10.9-17.0% for the case of monthly average hourly radiation. The proposed model has the advantage in terms of the simplicity for applications and reasonable accuracy of the results.

  1. Solar radiation on Mars

    SciTech Connect

    Appelbaum, J.; Flood, D.J. )

    1990-01-01

    Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. In this paper the authors present a procedure and solar radiation related data from which the diurnally, hourly and daily variation of the global, direct beam and diffuse insolation on Mars are calculated. The radiation data are based on measured optical depth of the Martian atmosphere derived from images taken of the sun with a special diode on the Viking cameras; and computation based on multiple wavelength and multiple scattering of the solar radiation.

  2. Solar radiation on Mars

    NASA Technical Reports Server (NTRS)

    Appelbaum, Joseph; Flood, Dennis J.

    1989-01-01

    Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. Presented here is a procedure and solar radiation related data from which the diurnally, hourly and daily variation of the global, direct beam and diffuse insolation on Mars are calculated. The radiation data are based on measured optical depth of the Martian atmosphere derived from images taken of the sun with a special diode on the Viking cameras; and computation based on multiple wavelength and multiple scattering of the solar radiation.

  3. Modeling of solar radiation management: a comparison of simulations using reduced solar constant and stratospheric sulphate aerosols

    NASA Astrophysics Data System (ADS)

    Kalidindi, Sirisha; Bala, Govindasamy; Modak, Angshuman; Caldeira, Ken

    2015-05-01

    The climatic effects of Solar Radiation Management (SRM) geoengineering have been often modeled by simply reducing the solar constant. This is most likely valid only for space sunshades and not for atmosphere and surface based SRM methods. In this study, a global climate model is used to evaluate the differences in the climate response to SRM by uniform solar constant reduction and stratospheric aerosols. Our analysis shows that when global mean warming from a doubling of CO2 is nearly cancelled by both these methods, they are similar when important surface and tropospheric climate variables are considered. However, a difference of 1 K in the global mean stratospheric (61-9.8 hPa) temperature is simulated between the two SRM methods. Further, while the global mean surface diffuse radiation increases by ~23 % and direct radiation decreases by about 9 % in the case of sulphate aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~1.0 %) when solar constant is reduced. When CO2 fertilization effects from elevated CO2 concentration levels are removed, the contribution from shaded leaves to gross primary productivity (GPP) increases by 1.8 % in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 15.2 % decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~8 %) and net primary productivity (~3 %). Based on our results we conclude that the climate states produced by a reduction in solar constant and addition of aerosols into the stratosphere can be considered almost similar except for two important aspects: stratospheric temperature change and the consequent implications for the dynamics and the chemistry of the stratosphere and the partitioning of direct versus diffuse radiation reaching the surface. Further, the likely dependence of global hydrological cycle response on aerosol particle size and the latitudinal and

  4. A new solar radiation model for research and applications in Austria

    NASA Astrophysics Data System (ADS)

    Olefs, Dr.; Schoener, Dr.

    2012-04-01

    The operational model STRAHLGRID calculates 10 minute values of direct and diffuse solar radiation as well as sunshine duration on a 1x1km grid for the national territory of Austria in near realtime. The model accounts for atmospheric turbidity, cloudiness, terrain shading, multiple and terrain reflections and ground albedo feedbacks. To reproduce temporal changes of atmospheric turbidity at best, we use precipitable water (water vapour transmittance) and visibility fields (aerosol transmittance) from the ZAMG operational nowcasting model INCA at same spatial resolution as well as a cloud raster. The latter combines measured sunshine fraction at 249 automatic weather stations (TAWES) with cloud type from MSG-2 satellite data and is therefore directly relevant for solar radiation. It is updated every 15 minutes. To account for multiple reflections, the ground albedo is taken from daily available MODIS imagery. Terrain data (elevation, aspect, slope, ground and sky view factor) is taken from a 100x100m DEM extracted at every 10th grid cell. To validate the model, quality controlled global solar radiation and sunshine duration data from 232 automatic weather stations in Austria as well as direct and diffuse solar radiation data of 5 operational suntracking systems are used. At ZAMG, the model is operationally used to assist the legal task of a national climate monitoring in Austria, to perform data quality control, to provide input and verification data for modeling tasks on different temporal and spatial scales (e.g. energy balance, regional climate modeling, weather forecasting) and to derive products related to solar energy applications (longterm means and forecasts). In future, the model will be used as an important part of a planned national operational snow cover model. The model data is freely available for academic and research use.

  5. Kingdom of Saudi Arabia Solar Radiation Atlas

    SciTech Connect

    NREL

    1998-12-16

    This atlas provides a record of monthly mean solar radiation generated by a Climatological Solar Radiation model, using quasi-climatological inputs of cloud cover, aerosol optical depth, precipitable water vapor, ozone, surface albedo, and atmospheric pressure.

  6. Box-wing model approach for solar radiation pressure modelling in a multi-GNSS scenario

    NASA Astrophysics Data System (ADS)

    Tobias, Guillermo; Jesús García, Adrián

    2016-04-01

    The solar radiation pressure force is the largest orbital perturbation after the gravitational effects and the major error source affecting GNSS satellites. A wide range of approaches have been developed over the years for the modelling of this non gravitational effect as part of the orbit determination process. These approaches are commonly divided into empirical, semi-analytical and analytical, where their main difference relies on the amount of knowledge of a-priori physical information about the properties of the satellites (materials and geometry) and their attitude. It has been shown in the past that the pre-launch analytical models fail to achieve the desired accuracy mainly due to difficulties in the extrapolation of the in-orbit optical and thermic properties, the perturbations in the nominal attitude law and the aging of the satellite's surfaces, whereas empirical models' accuracies strongly depend on the amount of tracking data used for deriving the models, and whose performances are reduced as the area to mass ratio of the GNSS satellites increases, as it happens for the upcoming constellations such as BeiDou and Galileo. This paper proposes to use basic box-wing model for Galileo complemented with empirical parameters, based on the limited available information about the Galileo satellite's geometry. The satellite is modelled as a box, representing the satellite bus, and a wing representing the solar panel. The performance of the model will be assessed for GPS, GLONASS and Galileo constellations. The results of the proposed approach have been analyzed over a one year period. In order to assess the results two different SRP models have been used. Firstly, the proposed box-wing model and secondly, the new CODE empirical model, ECOM2. The orbit performances of both models are assessed using Satellite Laser Ranging (SLR) measurements, together with the evaluation of the orbit prediction accuracy. This comparison shows the advantages and disadvantages of

  7. Modeling Suomi-NPP VIIRS Solar Diffuser Degradation due to Space Radiation

    NASA Astrophysics Data System (ADS)

    Shao, X.; Cao, C.

    2014-12-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi-NPP uses a solar diffuser (SD) as on-board radiometric calibrator for the reflective solar band (RSB) calibration. Solar diffuser is made of Spectralon (one type of fluoropolymer) and was chosen because of its controlled reflectance in the VIS-NIR-SWIR region and its near-Lambertian reflectance profile. Spectralon is known to degrade in reflectance at the blue end of the spectrum due to exposure to space radiations such as solar UV radiation and energetic protons. These space radiations can modify the Spectralon surface through breaking C-C and C-F bonds and scissioning or cross linking the polymer, which causes the surface roughness and degrades its reflectance. VIIRS uses a SDSM (Solar Diffuser Stability Monitor) to monitor the change in the Solar Diffuser reflectance in the 0.4 - 0.94 um wavelength range and provide a correction to the calibration constants. The H factor derived from SDSM reveals that reflectance of 0.4 to 0.6um channels of VIIRS degrades faster than the reflectance of longer wavelength RSB channels. A model is developed to derive characteristic parameters such as mean SD surface roughness height and autocovariance length of SD surface roughness from the long term spectral degradation of SD reflectance as monitored by SDSM. These two parameters are trended to assess development of surface roughness of the SD over the operation period of VIIRS.

  8. An optimisation methodology of artificial neural network models for predicting solar radiation: a case study

    NASA Astrophysics Data System (ADS)

    Rezrazi, Ahmed; Hanini, Salah; Laidi, Maamar

    2016-02-01

    The right design and the high efficiency of solar energy systems require accurate information on the availability of solar radiation. Due to the cost of purchase and maintenance of the radiometers, these data are not readily available. Therefore, there is a need to develop alternative ways of generating such data. Artificial neural networks (ANNs) are excellent and effective tools for learning, pinpointing or generalising data regularities, as they have the ability to model nonlinear functions; they can also cope with complex `noisy' data. The main objective of this paper is to show how to reach an optimal model of ANNs for applying in prediction of solar radiation. The measured data of the year 2007 in Ghardaïa city (Algeria) are used to demonstrate the optimisation methodology. The performance evaluation and the comparison of results of ANN models with measured data are made on the basis of mean absolute percentage error (MAPE). It is found that MAPE in the ANN optimal model reaches 1.17 %. Also, this model yields a root mean square error (RMSE) of 14.06 % and an MBE of 0.12. The accuracy of the outputs exceeded 97 % and reached up 99.29 %. Results obtained indicate that the optimisation strategy satisfies practical requirements. It can successfully be generalised for any location in the world and be used in other fields than solar radiation estimation.

  9. Solar F10.7 radiation - A short term model for Space Station applications

    NASA Technical Reports Server (NTRS)

    Vedder, John D.; Tabor, Jill L.

    1991-01-01

    A new method is described for statistically modeling the F10.7 component of solar radiation for 91-day intervals. The resulting model represents this component of the solar flux as a quasi-exponentially correlated, Weibull distributed random variable, and thereby demonstrates excellent agreement with observed F10.7 data. Values of the F10.7 flux are widely used in models of the earth's upper atmosphere because of its high correlation with density fluctuations due to solar heating effects. Because of the direct relation between atmospheric density and drag, a realistic model of the short term fluctuation of the F10.7 flux is important for the design and operation of Space Station Freedom. The method of modeling this flux described in this report should therefore be useful for a variety of Space Station applications.

  10. The Projection of Space Radiation Environments with a Solar Cycle Statistical Model

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.; Wilson, John W.

    2006-01-01

    A solar cycle statistical model has been developed to project sunspot numbers which represent the variations in the space radiation environment. The resultant projection of sunspot numbers in near future were coupled to space-related quantities of interest in radiation protection, such as the galactic cosmic radiation (GCR) deceleration potential (f) and the mean occurrence frequency of solar particle event (SPE). Future GCR fluxes have been derived from a predictive model, in which GCR temporal dependence represented by f was derived from GCR flux and ground-based Climax neutron monitor rate measurements over the last four decades. Results showed that the point dose equivalent inside a typical spacecraft in interplanetary radiation fields was influenced by solar modulation up to a factor of three. One important characteristic of sporadic SPEs is their mean frequency of occurrence, which is dependent on solar activity. Projections of future mean frequency of SPE occurrence were estimated from a power law function of sunspot number. Furthermore, the cumulative probabilities of SPE during short-period missions were defined with the continuous database of proton fluences of SPE. The analytic representation of energy spectra of SPE was constructed by the Weibull distribution for different event sizes. The representative exposure level at each event size was estimated for the guideline of protection systems for astronauts during future space exploration missions.

  11. A thermochemical model of radiation damage and annealing applied to GaAs solar cells

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    Calculations of the equilibrium conditions for continuous radiation damage and thermal annealing are reported. The calculations are based on a thermochemical model developed to analyze the incorporation of point imperfections in GaAs, and modified by introducing the radiation to produce native lattice defects rather than high-temperature and arsenic atmospheric pressure. The concentration of a set of defects, including vacancies, divacancies, and impurity vacancy complexes, are calculated as a function of temperature. Minority carrier lifetimes, short circuit current, and efficiency are deduced for a range of equilibrium temperatures. The results indicate that GaAs solar cells could have a mission life which is not greatly limited by radiation damage.

  12. Modeling of Solar Radiation Management: A Comparison of Simulations Using Reduced Solar Constant and Stratospheric Sulphate Aerosols

    NASA Astrophysics Data System (ADS)

    Bala, G.; Kalidindi, S.; Modak, A.; Caldeira, K.

    2014-12-01

    Several climate modelling studies in the past have used reduction in solar constant to simulate the climatic effects of Solar Radiation Management (SRM) geoengineering. This is most likely valid only for space-based mirrors/reflectors but not for SRM methods that rely on stratospheric aerosols. In this study, we use a climate model to evaluate the differences in climate response to SRM by uniform solar constant reduction and stratospheric aerosols. The experiments are designed such that global mean warming from a doubling of atmospheric CO2 concentration (2xCO2) is nearly cancelled in each case. In such a scenario, the residual climate effects are similar when important surface and tropospheric climate variables such as temperature and precipitation are considered. However, there are significant differences in stratospheric temperature response and diffuse and direct radiation reaching the surface. A difference of 1K in the global mean stratospheric (61-9.8 hPa) temperature is simulated between the two SRM methods, with warming in the aerosol scheme and a slight cooling for sunshades. While the global mean surface diffuse radiation increases by ~23% and direct radiation decreases by about 9% in the case of aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~1.0%) when solar constant is reduced. When CO2 fertilization effects from elevated CO2 concentration levels are removed, the contribution from shaded leaves to gross primary productivity (GPP) increases by 1.8 % in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 15.2% decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~ 8%) and NPP (~3%) relative to 2xCO2, indicating the negligible effect of the fractional changes in direct/diffuse radiation on the overall plant productivity. Based on our modelling study, we conclude that the climate states produced by a

  13. Potential solar radiation and land cover contributions to digital climate surface modeling

    NASA Astrophysics Data System (ADS)

    Puig, Pol; Batalla, Meritxell; Pesquer, Lluís; Ninyerola, Miquel

    2016-04-01

    Overview: We have designed a series of ad-hoc experiments to study the role of factors that a priori have a strong weight in developing digital models of temperature and precipitation, such as solar radiation and land cover. Empirical test beds have been designed to improve climate (mean air temperature and total precipitation) digital models using statistical general techniques (multiple regression) with residual correction (interpolated with inverse weighting distance). Aim: Understand what roles these two factors (solar radiation and land cover) play to incorporate them into the process of generating mapping of temperature and rainfall. Study area: The Iberian Peninsula and supported in this, Catalonia and the Catalan Pyrenees. Data: The dependent variables used in all experiments relate to data from meteorological stations precipitation (PL), mean temperature (MT), average temperature minimum (MN) and maximum average temperature (MX). These data were obtained monthly from the AEMET (Agencia Estatal de Meteorología). Data series of stations covers the period between 1950 to 2010. Methodology: The idea is to design ad hoc, based on a sample of more equitable space statistician, to detect the role of radiation. Based on the influence of solar radiation on the temperature of the air from a quantitative point of view, the difficulty in answering this lies in the fact that there are lots of weather stations located in areas where solar radiation is similar. This suggests that the role of the radiation variable remains "off" when, instead, we intuitively think that would strongly influence the temperature. We have developed a multiple regression analysis between these meteorological variables as the dependent ones (Temperature and rainfall), and some geographical variables: altitude (ALT), latitude (LAT), continentality (CON) and solar radiation (RAD) as the independent ones. In case of the experiment with land covers, we have used the NDVI index as a proxy of land

  14. Modelling canopy scale solar induced chlorophyll fluorescence simulated by the three dimensional radiative transfer model

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Nagai, S.; Inoue, T.; Yang, W.; Ichii, K.

    2014-12-01

    Recent studies show that the vegetation canopy scale sun-induced chlorophyll fluorescence (SIF) can be observed from satellite. To understand how the canopy scale bidirectional fluorescence observations are related to three-dimensional fluorescence distribution within a plant canopy, it is necessary to evaluate canopy scale fluorescence emission using a detailed plant canopy radiative transfer model. In this study, we developed a three-dimensional plant canopy radiative transfer model that can simulate the bidirectional chlorophyll fluorescence radiance and show several preliminary results of fluorescence distribution at the tree level. To simulate the three dimensional variations in chlorophyll fluorescence from trees, we measured tree structures using a terrestrial LiDAR instrument. The measurements were conducted in Yokohama, Japan (35°22'49" N 139°37'29" E). Three Japanese cherry trees (Cerasus Speciosa) were chosen for our study (Figure 1). Leaf-level sun-induced chlorophyll fluorescence (SIF) is also necessary as an input of radiative transfer model. To measure the leaf-level SIF, we used high spectral resolution spectroradiometer (HR 4000, Ocean Optics Inc. USA). The spectral resolution of this instrument is 0.05 nm (full width half maximum). The spectral range measured was 720 to 780 nm. From the spectral radiance measurements, we estimated SIF using the three band Fraunhofer Line Depth (3FLD) method. The effect of solar and view zenith angles, multiple scattering depends on many factors such as back ground reflectance, leaf reflectance transmittance and landscape structures. To understand how the SIF from both sparse and dense forest stands vary with sun and view angles and optical variables, it is necessary to conduct further sensitivity analysis. Radiative transfer simulation will help understand SIF emission at variety of forest canopy cases.

  15. Simulation model of a new solar laser system of Fresnel lens according to real observed solar radiation data in

    NASA Astrophysics Data System (ADS)

    Abdel-Hadi, Yasser A.; Ghitas, A.; Abulwfa, A.; Sabry, M.

    2015-12-01

    A new simulation model of a new solar pumped laser system was tested to be run in Helwan in Egypt (latitude φ = 29°52‧N, longitude λ = 31°21‧E and elevation = 141 m) as an example of an industrial polluted area. The system is based on concentrating the solar radiation using a Fresnel lens on a laser head fixed on a mount tracking the sun during the day and powered by a DC battery. Two cases of this model are tested; the first one is the model consisting of a Fresnel lens and a two-dimensional Compound Parabolic Concentrator (CPC), while the other is the model consisting of a Fresnel lens and a three-dimensional Compound Parabolic Concentrator (CPC). The model is fed by real actual solar radiation data taken in Helwan Solar Radiation Station at NRIAG in the various seasons in order to know the laser power got from such a system in those conditions. For the system of Fresnel lens and 2D-CPC, an average laser output power of 1.27 W in Winter, 2 W in Spring, 5 W in Summer and 4.68 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 3.24 W. For the system of Fresnel lens and 3D-CPC, an average laser output power of 3.28 W in Winter, 3.55 W in Spring, 7.56 W in Summer and 7.13 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 5.38 W.

  16. Solar cell radiation handbook

    NASA Technical Reports Server (NTRS)

    Carter, J. R., Jr.; Tada, H. Y.

    1973-01-01

    A method is presented for predicting the degradation of a solar array in a space radiation environment. Solar cell technology which emphasizes the cell parameters that degrade in a radiation environment, is discussed along with the experimental techniques used in the evaluation of radiation effects. Other topics discussed include: theoretical aspects of radiation damage, methods for developing relative damage coefficients, nature of the space radiation environment, method of calculating equivalent fluence from electron and proton energy spectrums and relative damage coefficients, and comparison of flight data with estimated degradation.

  17. Secular orbit variation due to solar radiation effects: a detailed model for BYORP

    NASA Astrophysics Data System (ADS)

    McMahon, Jay; Scheeres, Daniel

    2010-03-01

    A detailed derivation of the effect of solar radiation pressure on the orbit of a body about a primary orbiting the Sun is given. The result is a set of secular equations that can be used for long-term predictions of changes in the orbit. Solar radiation pressure is modeled as a Fourier series in the body’s rotation state, where the coefficients are based on the shape and radiation properties of the body as parameters. In this work, the assumption is made that the body is in a synchronous orbit about the primary and rotates at a constant rate. This model is used to write explicit variational equations of the energy, eccentricity vector, and angular momentum vector for an orbiting body. Given that the effect of the solar radiation pressure and the orbit are periodic functions, they are readily averaged over an orbit. Furthermore, the equations can be averaged again over the orbit of the primary about the Sun to give secular equations for long-term prediction. This methodology is applied to both circular and elliptical orbits, and the full equations for secular changes to the orbit in both cases are presented. These results can be applied to natural systems, such as the binary asteroid system 1999 KW4, to predict their evolution due to the Binary YORP effect, or to artificial Earth orbiting, nadir-pointing satellites to enable more precise models for their orbital evolution.

  18. [Model of control of diurnal melatonin secretion by the solar radiation].

    PubMed

    Leonidov, A V

    2014-01-01

    The mathematical model of the control process of diurnal melatonin secretion under the influence of solar radiation on retina photoreceptors is proposed. Invariant relations for calculating melatonin secretion rate and its concentration in blood plasma are obtained. Spectral, time and energy characteristics of solar radiation synchronizing diurnal melatonin secretion and circadian rhythms in human are defined. A possibility of using the relations obtained is shown for arbitrary combination of calendar dates, local time of any time zone and geographical coordinates of a calculated point on earth surface. The adequacy of model is confirmed by coincidence of the calculation data with the results of independent experimental studies on diurnal secretion of melatonin and circadian rhythm in human. The model proposed can be used during investigation of diurnal secretion of melatonin and circadian rhythm in human. PMID:25707251

  19. Methods to estimate solar radiation dosimetry in coral reefs using remote sensed, modeled, and in situ data.

    PubMed

    Barron, Mace G; Vivian, Deborah N; Yee, Susan H; Santavy, Deborah L

    2009-04-01

    Solar irradiance has been increasingly recognized as an important determinant of bleaching in coral reefs, but measurements of solar radiation exposure within coral reefs have been relatively limited. Solar radiation dosimetry within multiple coral reef areas of South Florida was assessed using remote sensed, modeled, and measured values during a minor bleaching event during August 2005. Coral reefs in the Dry Tortugas and Upper Keys had similar diffuse downwelling attenuation coefficients (Kd, m(-1)), whereas Kd values were significantly greater in the Middle and Lower Keys. Mean 1% attenuation depths varied by reef region for ultraviolet B (UVB; 9.7 to 20 m), ultraviolet A (UVA; 22 to 40 m) and visible (27 to 43 m) solar radiation. Solar irradiances determined from remote sensed data were significantly correlated with measured values, but were generally overestimated at the depth of corals. Solar irradiances modeled using an atmospheric radiative transfer model parameterized with site specific approximations of cloud cover showed close agreement with measured values. Estimated daily doses (W h/m(2)) of UVB (0.01-19), UVA (2-360) and visible (29-1,653) solar radiation varied with coral depth (2 to 24 m) and meteorological conditions. These results indicate large variation in solar radiation dosimetry within coral reefs that may be estimated with reasonable accuracy using regional Kd measurements and radiative transfer modeling. PMID:18581248

  20. Statistical Modeling of Spatio-Temporal Variability in Monthly Average Daily Solar Radiation over Turkey

    PubMed Central

    Evrendilek, Fatih; Ertekin, Can

    2007-01-01

    Though one of the most significant driving forces behind ecological processes such as biogeochemical cycles and energy flows, solar radiation data are limited or non-existent by conventional ground-based measurements, and thus, often estimated from other meteorological data through (geo)statistical models. In this study, spatial and temporal patterns of monthly average daily solar radiation on a horizontal surface at the ground level were quantified using 130 climate stations for the entire Turkey and its conventionally-accepted seven geographical regions through multiple linear regression (MLR) models as a function of latitude, longitude, altitude, aspect, distance to sea; minimum, maximum and mean air temperature and relative humidity, soil temperature, cloudiness, precipitation, pan evapotranspiration, day length, maximum possible sunshine duration, monthly average daily extraterrestrial solar radiation, and time (month), and universal kriging method. The resulting 20 regional best-fit MLR models (three MLR models for each region) based on parameterization datasets had R2adj values of 91.5% for the Central Anatolia region to 98.0% for the Southeast Anatolia region. Validation of the best-fit MLR models for each region led to R2 values of 87.7% for the Mediterranean region to 98.5% for the Southeast Anatolia region. The best-fit anisotropic semi-variogram models for universal kriging as a result of one-leave-out cross-validation gave rise to R2 values of 10.9% in July to 52.4% in November. Surface maps of monthly average daily solar radiation were generated over Turkey, with a grid resolution of 500 m × 500 m.

  1. Secular Orbit Variation Due to Solar Radiation Effects: A Detailed Model for BYORP

    NASA Astrophysics Data System (ADS)

    McMahon, Jay W.; Scheeres, D. J.

    2009-05-01

    A detailed derivation of the eff ect of solar radiation pressure on the orbit of a body about a primary other than the Sun is given. The result is a set of secular equations that can be used for long-term predictions of changes in the orbit. Solar radiation pressure is modeled as a Fourier series in the body's rotation state, where the coefficients include the shape and radiation properties of the body as parameters. In this work, the assumption is made that the body rotates at a constant rate such that it completes one rotation per orbit. This model is used to write explicit variational equations of the energy, eccentricity vector, and angular momentum vector for an orbiting body. Given that the e ffect of the solar radiation pressure and the orbit are periodic functions, they are readily averaged over an orbit. Furthermore, the equations can be averaged again over the orbit of the primary about the Sun to give secular equations for long-term prediction. This methodology is applied to both circular and elliptical orbits, and the results are discussed. These results can be applied to natural systems, such as the binary asteroid system KW4, to predict the evolution of the system due to the Binary YORP effect.

  2. Computer Modeling of Solar Ion Radiation Processing of Planetary Surface Materials

    NASA Astrophysics Data System (ADS)

    Chamberlin, Sydney; Christoffersen, Roy

    2007-10-01

    Airless bodies in the interstellar environment are constantly bombarded with ions from stellar winds. Resulting ion-atom interactions gradually cause chemical and structural changes to occur on their surfaces. One of the more significant changes is the formation of amorphous rims on regolith grains. Ion transport physics gives some description of the dynamics underlying such radiation damage, but gives little insight into other factors such as the width of the damaged layer and the degree of amorphization over time. Monte Carlo simulation programs for modeling ion-atom interactions exist, but have never been fully exploited for use in space radiation processing and fail to accommodate the range of parameters present in plasmas such as the solar wind. In this study we have utilized an existing Monte Carlo program, Transport and Range of Ions in Matter (TRIM), to model radiation in the space environment. A series of input data files and calculation protocols were created to investigate a range of typical solar wind parameters. The new outputs of the model consist of damage profiles for the amount of deposited ion collision energy as a function of ion angle, solar wind energy distribution, and sputtering rate. Results obtained with this model are found to be in reasonable agreement with experimental measured results from irradiated mineral grains.

  3. Dermatopathology effects of simulated solar particle event radiation exposure in the porcine model.

    PubMed

    Sanzari, Jenine K; Diffenderfer, Eric S; Hagan, Sarah; Billings, Paul C; Gridley, Daila S; Seykora, John T; Kennedy, Ann R; Cengel, Keith A

    2015-07-01

    The space environment exposes astronauts to risks of acute and chronic exposure to ionizing radiation. Of particular concern is possible exposure to ionizing radiation from a solar particle event (SPE). During an SPE, magnetic disturbances in specific regions of the Sun result in the release of intense bursts of ionizing radiation, primarily consisting of protons that have a highly variable energy spectrum. Thus, SPE events can lead to significant total body radiation exposures to astronauts in space vehicles and especially while performing extravehicular activities. Simulated energy profiles suggest that SPE radiation exposures are likely to be highest in the skin. In the current report, we have used our established miniature pig model system to evaluate the skin toxicity of simulated SPE radiation exposures that closely resemble the energy and fluence profile of the September, 1989 SPE using either conventional radiation (electrons) or proton simulated SPE radiation. Exposure of animals to electron or proton radiation led to dose-dependent increases in epidermal pigmentation, the presence of necrotic keratinocytes at the dermal-epidermal boundary and pigment incontinence, manifested by the presence of melanophages in the derm is upon histological examination. We also observed epidermal hyperplasia and a reduction in vascular density at 30 days following exposure to electron or proton simulated SPE radiation. These results suggest that the doses of electron or proton simulated SPE radiation results in significant skin toxicity that is quantitatively and qualitatively similar. Radiation-induced skin damage is often one of the first clinical signs of both acute and non-acute radiation injury where infection may occur, if not treated. In this report, histopathology analyses of acute radiation-induced skin injury are discussed. PMID:26256624

  4. Dermatopathology effects of simulated solar particle event radiation exposure in the porcine model

    NASA Astrophysics Data System (ADS)

    Sanzari, Jenine K.; Diffenderfer, Eric S.; Hagan, Sarah; Billings, Paul C.; Gridley, Daila S.; Seykora, John T.; Kennedy, Ann R.; Cengel, Keith A.

    2015-07-01

    The space environment exposes astronauts to risks of acute and chronic exposure to ionizing radiation. Of particular concern is possible exposure to ionizing radiation from a solar particle event (SPE). During an SPE, magnetic disturbances in specific regions of the Sun result in the release of intense bursts of ionizing radiation, primarily consisting of protons that have a highly variable energy spectrum. Thus, SPE events can lead to significant total body radiation exposures to astronauts in space vehicles and especially while performing extravehicular activities. Simulated energy profiles suggest that SPE radiation exposures are likely to be highest in the skin. In the current report, we have used our established miniature pig model system to evaluate the skin toxicity of simulated SPE radiation exposures that closely resemble the energy and fluence profile of the September, 1989 SPE using either conventional radiation (electrons) or proton simulated SPE radiation. Exposure of animals to electron or proton radiation led to dose-dependent increases in epidermal pigmentation, the presence of necrotic keratinocytes at the dermal-epidermal boundary and pigment incontinence, manifested by the presence of melanophages in the derm is upon histological examination. We also observed epidermal hyperplasia and a reduction in vascular density at 30 days following exposure to electron or proton simulated SPE radiation. These results suggest that the doses of electron or proton simulated SPE radiation results in significant skin toxicity that is quantitatively and qualitatively similar. Radiation-induced skin damage is often one of the first clinical signs of both acute and non-acute radiation injury where infection may occur, if not treated. In this report, histopathology analyses of acute radiation-induced skin injury are discussed.

  5. Dermatopathology effects of simulated solar particle event radiation exposure in the porcine model

    PubMed Central

    Sanzari, Jenine K.; Diffenderfer, Eric S.; Hagan, Sarah; Billings, Paul C.; Gridley, Daila S.; Seykora, John T.; Kennedy, Ann R.; Cengel, Keith A.

    2015-01-01

    The space environment exposes astronauts to risks of acute and chronic exposure to ionizing radiation. Of particular concern is possible exposure to ionizing radiation from a solar particle event (SPE). During an SPE, magnetic disturbances in specific regions of the Sun result in the release of intense bursts of ionizing radiation, primarily consisting of protons that have a highly variable energy spectrum. Thus, SPE events can lead to significant total body radiation exposures to astronauts in space vehicles and especially while performing extravehicular activities. Simulated energy profiles suggest that SPE radiation exposures are likely to be highest in the skin. In the current report, we have used our established miniature pig model system to evaluate the skin toxicity of simulated SPE radiation exposures that closely resemble the energy and fluence profile of the September, 1989 SPE using either conventional radiation (electrons) or proton simulated SPE radiation. Exposure of animals to electron or proton radiation led to dose-dependent increases in epidermal pigmentation, the presence of necrotic keratinocytes at the dermal-epidermal boundary and pigment incontinence, manifested by the presence of melanophages in the dermis upon histological examination. We also observed epidermal hyperplasia and a reduction in vascular density at 30 days following exposure to electron or proton simulated SPE radiation. These results suggest that the doses of electron or proton simulated SPE radiation results in significant skin toxicity that is quantitatively and qualitatively similar. Radiation-induced skin damage is often one of the first clinical signs of both acute and non-acute radiation injury where infection may occur, if not treated. In this report, histopathology analyses of acute radiation-induced skin injury are discussed. PMID:26256624

  6. SOLAR RADIATION, VA

    EPA Science Inventory

    Sterling, Virginia Integrated Surface Irradiance Study (ISIS) solar radiation data files from National Oceanic and Atmospheric Administration (NOAA), zipped from ftp://ftp.atdd.noaa.gov/pub/projects/isis/ste/monthly

  7. Comparison of Solar Analyst and r.sun Models to Estimate the Spatially Distributed Solar Radiation in a Mountainous Region in Iran

    NASA Astrophysics Data System (ADS)

    Norouzi, H.; Didari, S.; Zand-Parsa, S.

    2015-12-01

    Solar radiation plays a major role in the energy exchange process between the atmosphere and earth's surface. The spatial and temporal heterogeneity of incoming solar energy determines the dynamics of some landscape processes such as agricultural, hydrological, ecological and biological processes. Consequently, in order to understand these processes, knowledge of the spatial variability of solar radiation is crucial. At regional scales, particularly in complex topography, terrain is the major factor modifying the distribution of irradiation. Variability in elevation, surface inclination (slope) and orientation (aspect) and shadows cast by topographic features create strong local gradients of insolation which affects micro environmental factor. To account for spatio-temporal variations of solar radiation, spatially distributed DEM-based solar radiation models can be helpful. In this study, estimated daily solar radiation using Solar Analyst and r.sun solar radiation models were evaluated and compared in a mountainous region in south of Iran. The models were evaluated for different sky conditions ranged from completely overcast to clear sky conditions. The sensitivity of the models to the input, based on station data was also analyzed. Additionally, the role of the spatial resolution of the DEM has been evaluated through the use of three different resolutions: 30, 90 and 1000m. The results showed that, under clear-sky conditions, the models can estimate solar radiation favorably, but their accuracy was reduced in cloudy and party cloudy atmospheric conditions. However, the accuracy of r.sun model due to raster format of inputs was better than Solar Analyst model in presence of cloud in the sky. Regarding the role of the DEM spatial resolution, results showed that for complex topography areas, the accuracy of the estimates improves using a higher spatial resolution.

  8. Improving Space Object Catalog Maintenance Through Advances in Solar Radiation Pressure Modeling

    NASA Astrophysics Data System (ADS)

    McMahon, J.; Scheeres, D.

    This paper investigates the weaknesses of using the cannonball model to represent the solar radiation pressure force on an object in an orbit determination process, and presents a number of alternative models that greatly improve the orbit determination performance. These weaknesses are rooted in the fact that the cannonball model is not a good representation of the true solar radiation pressure force acting on an arbitrary object. Using an erroneous force model results in poor estimates, inaccurate trajectory propagation, unrealistic covariances, and the inability to fit long and/or dense arcs of data. The alternative models presented are derived from a Fourier series representation of the solar radiation pressure force. The simplest instantiation of this model requires only two more parameters to be estimated, however this results in orders of magnitude improvements in tracking accuracy. This improvement is illustrated through numerical examples of a discarded upper stage in a geosynchronous transfer orbit, and more drastically for a piece of high area-to-mass ratio debris in a near-geosynchronous orbit. The upper stage example shows that using the proposed 3-parameter model can improve the orbit fit from 5 days of tracking data by 2-4 orders of magnitude over the cannonball model. Perhaps more importantly, over a 28 day propagation arc with the estimated models, the prediction errors with the 3-parameter model rarely exceed 2-sigma of the propagated covariance, whereas the cannonball prediction errors grow to over 70-sigmaof the propagated covariance. Most significantly, we show that using the proposed Fourier model greatly improves estimation of HAMR debris orbits, where the cannonball model can struggle to fit the data at any level. In the most extreme case tested, fitting 3 short arcs of data each separated by 100 hours, the Fourier model fits the orbit to the centimeter level, while the cannonball model has errors on the order of 1000 km. Implementation of

  9. A simple model of space radiation damage in GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Stith, J. J.; Stock, L. V.

    1983-01-01

    A simple model is derived for the radiation damage of shallow junction gallium arsenide (GaAs) solar cells. Reasonable agreement is found between the model and specific experimental studies of radiation effects with electron and proton beams. In particular, the extreme sensitivity of the cell to protons stopping near the cell junction is predicted by the model. The equivalent fluence concept is of questionable validity for monoenergetic proton beams. Angular factors are quite important in establishing the cell sensitivity to incident particle types and energies. A fluence of isotropic incidence 1 MeV electrons (assuming infinite backing) is equivalent to four times the fluence of normal incidence 1 MeV electrons. Spectral factors common to the space radiations are considered, and cover glass thickness required to minimize the initial damage for a typical cell configuration is calculated. Rough equivalence between the geosynchronous environment and an equivalent 1 MeV electron fluence (normal incidence) is established.

  10. Regression model for estimating inactivation of microbial aerosols by solar radiation.

    PubMed

    Ben-David, Avishai; Sagripanti, Jose-Luis

    2013-01-01

    The inactivation of pathogenic aerosols by solar radiation is relevant to public health and biodefense. We investigated whether a relatively simple method to calculate solar diffuse and total irradiances could be developed and used in environmental photobiology estimations instead of complex atmospheric radiative transfer computer programs. The second-order regression model that we developed reproduced 13 radiation quantities calculated for equinoxes and solstices at 35(°) latitude with a computer-intensive and rather complex atmospheric radiative transfer program (MODTRAN) with a mean error <6% (2% for most radiation quantities). Extending the application of the regression model from a reference latitude and date (chosen as 35° latitude for 21 March) to different latitudes and days of the year was accomplished with variable success: usually with a mean error <15% (but as high as 150% for some combination of latitudes and days of year). This accuracy of the methodology proposed here compares favorably to photobiological experiments where the microbial survival is usually measured with an accuracy no better than ±0.5 log10 units. The approach and equations presented in this study should assist in estimating the maximum time during which microbial pathogens remain infectious after accidental or intentional aerosolization in open environments. PMID:23445252

  11. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    PubMed Central

    Mirzabozorg, H.; Hariri-Ardebili, M. A.; Shirkhan, M.; Seyed-Kolbadi, S. M.

    2014-01-01

    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817

  12. Mathematical modeling and numerical analysis of thermal distribution in arch dams considering solar radiation effect.

    PubMed

    Mirzabozorg, H; Hariri-Ardebili, M A; Shirkhan, M; Seyed-Kolbadi, S M

    2014-01-01

    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817

  13. Implications for space radiation environment models from CREAM & CREDO measurements over half a solar cycle.

    PubMed

    Dyer, C S; Truscott, P R; Peerless, C L; Watson, C J; Evans, H E; Knight, P; Cosby, M; Underwood, C; Cousins, T; Noulty, R; Maag, C

    1999-10-01

    Flight data obtained between 1990 and 1997 from the Cosmic Radiation Environment Monitors CREAM & CREDO carried on UoSAT-3, Space Shuttle, STRV-1a (Space Technology Research Vehicle) and APEX (Advanced Photovoltaic and Electronics Experiment Spacecraft) provide coverage over half a solar cycle. The modulation of cosmic rays and evolution of the South Atlantic Anomaly are observed, the former comprising a factor of three increase at high latitudes and the latter a general increase accompanied by a north-westward drift. Comparison of particle fluxes and linear energy transfer (LET) spectra is made with improved environment & radiation transport calculations which account for shield distributions and secondary particles. While there is an encouraging convergence between predictions and observations, significant improvements are still required, particularly in the treatment of locally produced secondary particles. Solar-particle events during this time period have LET spectra significantly below the October 1989 event which has been proposed as a worst case model. PMID:11542668

  14. Solar radiation and precipitable water modeling for Turkey using artificial neural networks

    NASA Astrophysics Data System (ADS)

    Şenkal, Ozan

    2015-08-01

    Artificial neural network (ANN) method was applied for modeling and prediction of mean precipitable water and solar radiation in a given location and given date (month), given altitude, temperature, pressure and humidity in Turkey (26-45ºE and 36-42ºN) during the period of 2000-2002. Resilient Propagation (RP) learning algorithms and logistic sigmoid transfer function were used in the network. To train the network, meteorological measurements taken by the Turkish State Meteorological Service (TSMS) and Wyoming University for the period from 2000 to 2002 from five stations distributed in Turkey were used as training data. Data from years (2000 and 2001) were used for training, while the year 2002 was used for testing and validating the model. The RP algorithm were first used for determination of the precipitable water and subsequently, computation of the solar radiation, in these stations Root Mean Square Error (RMSE) between the estimated and measured values for monthly mean daily sum for precipitable water and solar radiation values have been found as 0.0062 gr/cm2 and 0.0603 MJ/m2 (training cities), 0.5652 gr/cm2 and 3.2810 MJ/m2 (testing cities), respectively.

  15. Incorporating solar radiation into the litter moisture model in the Canadian Forest Fire Danger Rating System

    NASA Astrophysics Data System (ADS)

    Wotton, Mike; Gibos, Kelsy

    2010-05-01

    The Canadian Forest Fire Danger Rating System (CFFDRS) is used throughout Canada, and in a number of countries throughout the world, for estimating fire potential in wildland fuels. The standard fuel moisture models in the CFFDRS are representative of moisture in closed canopy jack pine or lodge pole pine stands. These models assume full canopy closure and do not therefore account for the influence of solar radiation and thus cannot readily be adapted to more open environments. Recent research has seen the adaptation of the CFFDRS's hourly Fine Fuel Moisture Code (FFMC) model (which represents litter moisture) to open grasslands, through the incorporation of an explicit solar radiation term. This current study describes more recent extension of this modelling effort to forested stand situations. The development and structure of this new model is described and outputs of this new model, along with outputs from the existing FFMC model, are compared with field observations. Results show that the model tracks the diurnal variation in actual litter moisture content more accurately than the existing model for diurnal calculation of the FFMC in the CFFDRS. Practical examples of the application of this system for operational estimation of litter moisture are provided for stands of varying densities and types.

  16. Progress in Projecting Solar Radiation at the Earth's Surface in Climate Models

    NASA Astrophysics Data System (ADS)

    Collins, W.; Fildier, B.; Feldman, D.

    2015-12-01

    Projecting changes in solar radiation at the Earth's surface in futureclimates is a critical input to forecast surface irradiance for solarenergy. We demonstrate the current state of the art using theensemble of opportunity assembled for the Coupled ModelIntercomparison Project (CMIP5) and the Fifth Assessment Report (AR5)of the Intergovernmental Panel on Climate Change (IPCC). The reliability of these projections depends upon the accuracy of theunderlying radiation codes, the fidelity of these codes to themeasured optical properties of key radiatively active atmosphericconstituents, and the realism of future projections of theseatmospheric constituents. These constituents include aerosols,clouds, water vapor, greenhouse gases that absorb near-infraredsunlight. Since the realism of future projections of anthropogenicaerosol species is contingent on the underlying scenario, we focus onthe other challenges in forecasting surface irradiance. Regarding accuracy, we demonstrate that current GCM shortwaveparameterizations often exhibit quite small errors relative tobenchmark radiative transfer codes. In addition, recent work hasbracketed the uncertainties in solar irradiance associated withcomplex cloud geometries. There is also an emerging consensus howcloud radiative effects will evolve in a warmer climate. However,there is evidence that current GCM codes still exhibit systematicerrors in the near-infrared water vapor bands, particularly for moistsub-tropical atmospheres. These errors will become more acute aswater vapor feedbacks, combined with global warming, increase thetotal precipitable water in the Earth's atmosphere.

  17. Radiation belt electron reanalysis over two solar cycles: Comparitive modeling and analysis of several geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Kellerman, Adam; Turner, Drew; Kondrashov, Dmitri; Shprits, Yuri; Podladchikova, Tatiana; Drozdov, Alexander

    Earth’s electron radiation belts are a dynamic system, coupled to the solar wind and to the ionosphere. Understanding the observed dynamics requires consideration of the coupling between the three systems. Remote sensing and in situ observations provide information on the current state of the radiation belt system, and together with careful modeling may be used to resolve the physical processes at work. The Versatile Electron Radiation Belt (VERB) model solves the Fokker-Planck diffusion equation in three dimensional invariant coordinates, which allows one to more effectively separate adiabatic and non-adiabatic changes in the radiation belt electron population. The model includes geomagnetic storm intensity dependent parameterizations of the following dominant magnetospheric waves: day- and night-side chorus, plasmaspheric hiss (in the inner magnetosphere and inside the plume region), lightning and anthropogenic generated waves, and electro-magnetic ion cyclotron (EMIC) waves, also inside of plasmaspheric plumes. The model is used to forecast the future state of the radiation belt electron population, while real-time data may be used to update the current state of the belts through assimilation with the model. The Kalman filter provides a computationally inexpensive method to assimilate data with a model, while taking into account the errors associated with each. A split-operator Kalman filter approach is applied in this study, which provides a fast and effective way to assimilate data over very long time periods. Data error estimates are derived through the intercalibration, while model error estimates are adjusted dynamically based on the model forecast performance. In the current study, a set of geomagnetic storms are investigated comparatively using solar wind data, and reanalysis of electron phase space density from several different spacecraft missions. The storms occurred during periods that span over two solar cycles, and include CME and CIR driven

  18. 1961-1990 Solar Radiation Data Base

    SciTech Connect

    Not Available

    1990-01-01

    A new 1961-1990 Solar Radiation Data Base for the United States is being compiled at the Solar Energy Research Institute. Using solar radiation and climate data collected by the National Weather Service (NWS) from 1977 to 1990 and improved computer models to fill in missing data, this update will significantly upgrade the current national SOLMET/ERSATZ data base.

  19. Radiative modeling of solar prominences, two-dimensional transfer plus partial frequency redistribution

    NASA Astrophysics Data System (ADS)

    Paletou, F.; Vial, Jean-Claude; Auer, L. H.

    1992-11-01

    The two dimensional (2D) PRD (Partial Redistribution) radiative transfer code of Auer and Paletou was used to compute the resonance lines of HI, MgII and CaII in quiescent prominences, which are modeled as isothermal freestanding slabs illuminated from the sides as well as from below. PRD and 2D effects are evidenced and compared to Complete Redistribution (CRD) computations for both 1D and 2D geometries. Important edge variations are found at the bottom and the top that should be observed with a spatial resolution of one arcsecond. As in 1D, PRD effects allow for greater penetration of the incident radiation into the layer. The 2D code computes both the radial emergent intensity and the amount of radiation backscattered into the chromosphere. It can accordingly, be used to estimate the visibility of filaments. It will be of special interest to build nonisothermal models and compare, for example the Ly alpha profiles with the SUMER/SOHO (Solar Ultraviolet Measurement of Emitted Radiation)/(Solar and Heliospheric Observatory) observations.

  20. Macroscopic Models of Radiative Transfer as Applied to Computation of the Radiation Field in the Solar Atmosphere

    NASA Technical Reports Server (NTRS)

    Ripoll, J.-F.; Wray, A. A.

    2003-01-01

    In this paper a new three dimensional half-moment model for radiative transfer is presented for a gray medium. It describes the evolution of the zeroth and first directional half moments of the radiative intensity. The closure is provided, similarly to Dubroca and Klar, by the maximum entropy concept. This work generalizes that model to three dimensions. The model presented here (the derivation being done in Ripoll and Wray, called the M(sup 1/2)(sub 1) model, is a hyperbolic system consisting of a total of eight equations in three dimensions, four equations for each direction. Each half model has the classical form of a macroscopic moment model in which the pressure tensor is constructed from the well-known Eddington tensor with a particular Eddington factor. Moreover, different source and border terms occur. The latter introduce couplings between the macroscopic and microscopic quantities and between the + and - streams, through the intensity in the plane perpendicular to the flux. The main theoretical application of the half moment model, treated in this paper, is its reduction to a full moment model, called M(sup +)(sub 1), for the particular but important case of a hot, opaque source radiating in a cold transparent (or semi-transparent) medium for very specific applications, such as stellar interiors or atmospheres, or combustion problems. The structure of the paper is as follows. In section 2, the model M(sup 1/2)(sub 1) is presented. In section 3, for the particular case of a hot, opaque source radiating into a cold medium, the half moment model is reduced to the M(sup +)(sub 1) model. In section 4, we first solve a simple and academic problem to validate the models, followed by a simplified solar atmosphere.

  1. Coupled Modeling of Geomorphology and Ecohydrology: Topographic feedbacks driven by solar radiation

    NASA Astrophysics Data System (ADS)

    Istanbulluoglu, E.; Flores Cervantes, J. H.; Yetemen, O.

    2012-12-01

    There is a two-way coupling between geomorphic processes and vegetation dynamics. To examine the role of vegetation on landform development, landscape evolution models (LEMs) have used relatively simple theory of erosion-vegetation interactions and vegetation dynamics based on field evidence and conjecture. Such modeling studies have described "with broad strokes" the control of vegetation on landscape relief, drainage density, and sediment yields in a range of model sensitivity studies, often without any direct field confirmation. For improved predictions of climate-landscape relations in real-world cases, and identify the need for future model development, there is strong need for field confirmations of ecohydrologic LEMs. In this talk, we first discuss some of the key findings of recent LEM studies that incorporate vegetation. Second, we introduce the role of solar radiation on ecohydrologic processes in the CHILD LEM, and confirm model predictions against observations. Using the model we examine how solar radiation control the spatio-temporal dynamics of soil moisture, vegetation biomass, and their feedback on landform development in a semi-arid climate across a latitude gradient. We identify that at the catchment scale while the initial greening usually takes places relatively uniformly in space, the growing season takes longer on north facing slopes leading to higher overall biomass on north aspects. Through eco-geomorphic feedbacks, this leads to steeper north facing slopes, and increased valley asymmetry in the modeled landscapes. These findings are important to improve the predictions of climate change impacts on the landscape system.

  2. Cloud and solar radiation biases over the Southern Ocean in climate models (Invited)

    NASA Astrophysics Data System (ADS)

    Bodas-Salcedo, A.; Williams, K. D.; Hyder, P.; Edwards, J. M.; Copsey, D.

    2013-12-01

    Current climate models generally reflect too little solar radiation over the Southern Ocean, which may be the leading cause of the prevalent sea-surface temperature biases in climate models. We study the role of clouds on the solar radiation biases in atmosphere-only simulations of the Cloud Feedback Model Intercomparison Project phase 2 (CFMIP2), which is part of the Climate Model Intercomparison Project phase 5 (CMIP5). The CFMIP2 protocol requests additional diagnostics that are useful to investigate the causes of cloud and radiation biases in models, and their relation with cloud feedbacks. We composite AMIP daily data around cyclone centres in the latitude band between 40S and 70S during the summer. Most of the model biases occur in the cold air side of the cyclone composite, away from the cold front. We show that the cyclone composite accounts for most of the climatological error in that latitudinal band. We then use cloud property estimates from the International Cloud Climatology Project (ISCCP) to classify clouds into different regimes, following the clustering technique of Williams and Webb (2009). The cloud regime labelled as 'mid-level' is the main contributor to the Southern Ocean shortwave radiation biases. We use information from the CALIPSO lidar to investigate in more detail the properties of the 'mid-level' cloud regime. CALIPSO shows that the 'mid-level' cloud regime is dominated by two main cloud types; cloud with tops actually at mid-level, and low-level cloud. We will also present initial analyses of biases in air-sea fluxes over the Southern Ocean in the most recent configuration of the Met Office coupled model.

  3. Sources of solar radiation estimates and their effect on daily potential evaporation for use in streamflow modeling

    NASA Astrophysics Data System (ADS)

    Lindsey, Scott D.; Farnsworth, Richard K.

    1997-12-01

    The accurate estimation of potential evaporation (PE), to in turn calculate evapotranspiration, is an important step in many hydrologic models. The National Weather Service (NWS) has used PE to obtain daily estimates of mean evapotranspiration in continuous rainfall-runoff models for river forecasting. The daily PE estimates are derived mainly from meteorological data gathered on a regular basis throughout the country. Solar radiation is one of the required input variables. Because of its widespread availability, sky cover is now used almost exclusively by NWS to estimate solar radiation. Over a period of time, a bias has developed between the long-term mean PE (computed using a combination of historical observed pan evaporation data and meteorological data) and PE estimated operationally using real-time meteorological data. This difference is a result of the use of sky cover based solar radiation estimates. These biased solar radiation estimates translate into long-term means of PE which are significantly lower than values using corresponding direct measurements of solar radiation or estimates of solar radiation using percent sunshine. A standard for PE has been established and verified to which long-term means can be compared. PE estimates derived from sky cover can be corrected to the standard using a ratio of long-term means. Many meteorological variables which have been measured or observed manually in the past are being converted to automatic observations. With the advent of automated sensors, which do not duplicate the manual sky cover observations, another source of solar radiation is necessary to model PE for use in river forecasting. Satellite estimates of solar radiation are compared with other means of measuring and estimating solar radiation. Available on a nationwide basis, satellite estimates produce values of solar radiation comparable to those obtained by direct measurement. Based on availability and accuracy, satellite estimates of solar radiation

  4. Key Parameters for the Inconsistencies of the Incoming Solar Radiation Boundary Condition in Global Modeling

    NASA Astrophysics Data System (ADS)

    Tsushima, Yoko; Raschke, Ehrhard; Kinne, Stefan; Abe-Ouchi, Ayako; Bakan, Stefan; Emori, Seita; Giorgetta, Marco; Kopp, Greg; Saito, Fuyuki; Timm, Oliver; Wild, Martin

    2009-03-01

    By a comparison of the insolation, computed by 19 different climate models for the International Panel on Climate Change Fourth Assessment Report (IPCC-AR4) test period from 1980 to 1999, it is shown that those models used different values for the solar constant and for its solar cycle variations. Meridional profiles for the monthly incoming radiation displayed diversities of up to ±10 Wm-2, especially during the transient seasons. Sensitivity studies with minima and maxima for the assumed orbital parameters of the Earth show almost no change. However, the different temporal partitioning for onset and length of individual months based on different calendars (e.g. simplifications such as 30 days for each month) results in the difference in the insolation, which is strongly resemble in amount and in zonal pattern the observed diversity of the insolation in IPCC models. Contributing error sources are also different assumptions for cut-off angles at low sun-elevations and differences in increment-difference during spatial and temporal integrations. Possible impacts of these contributing errors in climate modeling are investigated within a coupled ocean-atmosphere model. It is found that monthly radiative fluxes, humidity, and temperature have a difference between the two vernal equinox experiments. Although it remained within the magnitude of the inter-model difference, the difference is systematic.

  5. Modeling the Dynamical Coupling of Solar Convection with the Radiative Interior

    NASA Astrophysics Data System (ADS)

    Brun, Allan Sacha; Miesch, Mark S.; Toomre, Juri

    2011-12-01

    The global dynamics of a rotating star like the Sun involves the coupling of a highly turbulent convective envelope overlying a seemingly benign radiative interior. We use the anelastic spherical harmonic code to develop a new class of three-dimensional models that nonlinearly couple the convective envelope to a deep stable radiative interior. The numerical simulation assumes a realistic solar stratification from r = 0.07 up to 0.97R (with R the solar radius), thus encompassing part of the nuclear core up through most of the convection zone. We find that a tachocline naturally establishes itself between the differentially rotating convective envelope and the solid body rotation of the interior, with a slow spreading that is here diffusively controlled. The rapid angular momentum redistribution in the convective envelope leads to a fast equator and slow poles, with a conical differential rotation achieved at mid-latitudes, much as has been deduced by helioseismology. The convective motions are able to overshoot downward about 0.04R into the radiative interior. However, the convective meridional circulation there is confined to a smaller penetration depth and is directed mostly equatorward at the base of the convection zone. Thermal wind balance is established in the lower convection zone and tachocline but departures are evident in the upper convection zone. Internal gravity waves are excited by the convective overshooting, yielding a complex wave field throughout the radiative interior.

  6. MODELING THE DYNAMICAL COUPLING OF SOLAR CONVECTION WITH THE RADIATIVE INTERIOR

    SciTech Connect

    Brun, Allan Sacha; Toomre, Juri

    2011-12-01

    The global dynamics of a rotating star like the Sun involves the coupling of a highly turbulent convective envelope overlying a seemingly benign radiative interior. We use the anelastic spherical harmonic code to develop a new class of three-dimensional models that nonlinearly couple the convective envelope to a deep stable radiative interior. The numerical simulation assumes a realistic solar stratification from r = 0.07 up to 0.97R (with R the solar radius), thus encompassing part of the nuclear core up through most of the convection zone. We find that a tachocline naturally establishes itself between the differentially rotating convective envelope and the solid body rotation of the interior, with a slow spreading that is here diffusively controlled. The rapid angular momentum redistribution in the convective envelope leads to a fast equator and slow poles, with a conical differential rotation achieved at mid-latitudes, much as has been deduced by helioseismology. The convective motions are able to overshoot downward about 0.04R into the radiative interior. However, the convective meridional circulation there is confined to a smaller penetration depth and is directed mostly equatorward at the base of the convection zone. Thermal wind balance is established in the lower convection zone and tachocline but departures are evident in the upper convection zone. Internal gravity waves are excited by the convective overshooting, yielding a complex wave field throughout the radiative interior.

  7. Development of GWNU (Gangneung-Wonju National University) one-layer transfer model for calculation of solar radiation distribution of the Korean peninsula

    NASA Astrophysics Data System (ADS)

    Zo, Il-Sung; Jee, Joon-Bum; Lee, Kyu-Tae

    2014-11-01

    Gangneung-Wonju National University (GWNU) one-layer solar radiation model is developed in order to resolve the lack of the vertical structure of atmospheric components and fast calculation with high horizontal spatial resolution. GWNU model is based on IQBAL and NREL methods and corrected by precise multi-layer Line-By-Line (LBL) model. Further, the amount of solar radiation reaching the surface by using 42 types of vertical atmospheric data as input data was compared with detailed models and one-layer models. One-layer solar radiation models were corrected depending on sensitivity of each input data (i.e., total precipitable water, ozone, mixed gas, and solar zenith angle). Global solar radiation was calculated by corrected GWNU solar model with satellites (MODIS, OMI and MTSAT-2), KLAPS model prediction data in Korea peninsula in 2010, and the results were compared to surface solar radiation observed by 22 KMA solar radiation sites. Calculated solar radiation annually accumulated showed highest solar radiation distribution in Andong, Daegu, and Jinju regions, meanwhile the observation data showed lower solar radiation in Daegu region compared to model result values.

  8. Status of the solar and infrared radiation submodels in the LLNL 1-D and 2-D chemical-transport models

    SciTech Connect

    Grant, K.E.; Taylor, K.E.; Ellis, J.S.; Wuebbles, D.J.

    1987-07-01

    The authors have implemented a series of state of the art radiation transport submodels in previously developed one dimensional and two dimensional chemical transport models of the troposphere and stratosphere. These submodels provide the capability of calculating accurate solar and infrared heating rates. They are a firm basis for further radiation submodel development as well as for studying interactions between radiation and model dynamics under varying conditions of clear sky, clouds, and aerosols. 37 refs., 3 figs.

  9. Improving the S-Shape Solar Radiation Estimation Method for Supporting Crop Models

    PubMed Central

    Fodor, Nándor

    2012-01-01

    In line with the critical comments formulated in relation to the S-shape global solar radiation estimation method, the original formula was improved via a 5-step procedure. The improved method was compared to four-reference methods on a large North-American database. According to the investigated error indicators, the final 7-parameter S-shape method has the same or even better estimation efficiency than the original formula. The improved formula is able to provide radiation estimates with a particularly low error pattern index (PIdoy) which is especially important concerning the usability of the estimated radiation values in crop models. Using site-specific calibration, the radiation estimates of the improved S-shape method caused an average of 2.72 ± 1.02 (α = 0.05) relative error in the calculated biomass. Using only readily available site specific metadata the radiation estimates caused less than 5% relative error in the crop model calculations when they were used for locations in the middle, plain territories of the USA. PMID:22645451

  10. A real-time solar wind and interplanetary magnetic field model for space radiation analysis and prediction

    NASA Astrophysics Data System (ADS)

    Fry, C. D.; Detman, T. R.; Dryer, M.; Smith, Z.; Sun, W.; Deehr, C. S.; Akasofu, S.-I.; Wu, C.-C.

    We describe an observation-driven model for assessing and predicting the solar wind and interplanetary magnetic field (IMF) environment. High energy particles generated during solar/interplanetary disturbances will pose a serious hazard to crew members traveling beyond low-Earth orbit. In order to provide warnings of dangerous radiation conditions, mission operators will need accurate forecasts of solar energetic particle (SEP) fluxes and fluences in interplanetary space. However, physics-based models for accelerating and propagating SEPs require specifications and predictions of the solar wind conditions and IMF configuration near the evolving interplanetary shock region, and along the IMF lines connecting the shock to the observation point. We are presently using the Hakamada-Akasofu-Fry kinematic solar wind model to predict, in real time, solar wind conditions in the heliosphere, including at the location of Mars, and beyond. This model is being extended via a hybrid approach to include a 3D MHD model, the Interplanetary Global Model, Vectorized (IGMV). We present our modeling results and conclude that uncertainties in determining, from real-time solar observations, the physical parameters used for model inputs are the biggest factors limiting the accuracy of solar wind models used for space radiation analysis and prediction.

  11. On modeling the organization of landscapes and vegetation patterns controlled by solar radiation

    NASA Astrophysics Data System (ADS)

    Istanbulluoglu, E.; Yetemen, O.

    2014-12-01

    Solar radiation is a critical driver of ecohydrologic processes and vegetation dynamics. Patterns of runoff generation and vegetation dictate landscape geomorphic response. Distinct patterns in the organization of soil moisture, vegetation type, and landscape morphology have been documented in close relation to aspect in a range of climates. Within catchments, from north to south facing slopes, studies have shown ecotone shifts from forest to shrub species, and steep diffusion-dominated landforms to fluvial landforms. Over the long term differential evolution of ecohydrology and geomorphology leads to observed asymmetric structure in the planform of channel network and valley morphology. In this talk we present examples of coupled modeling of ecohydrology and geomorphology driven by solar radiation. In a cellular automata model of vegetation dynamics we will first show how plants organize in north and south facing slopes and how biodiversity changes with elevation. When vegetation-erosion feedbacks are coupled emergent properties of the coupled system are observed in the modeled elevation and vegetation fields. Integrating processes at a range of temporal and spatial scales, coupled models of ecohydrologic and geomorphic dynamics enable examination of global change impacts on landscapes and ecosystems.

  12. Measurement and modeled data of solar spectral global direct and diffuse radiation at Valencia (Spain)

    NASA Astrophysics Data System (ADS)

    Cachorro, Victoria E.; de Frutos, Angel M.; Utrillas, Pilar; Martinez-Lozano, Jose A.

    1994-12-01

    Since December, 1992 a continuing data bank of measurements of global, direct and diffuse solar irradiance for clear skies is being compiled at Valencia, Spain). The measurements are performed with the commercial LICOR spectroradiometer from 300 - 1100 nm with a spectral resolution of 6 nm. As a complementary work to irradiance measurements an extensive comparative task is being carried out between these experimental data and modelled ones. The chosen model is a detailed narrow band model developed at the Laboratoire d'Optique Atmospherique of the Universite of Lille, France) which uses a two-flux method to solve the radiative transfer equation. The multilayer model (17 atmospheric levels) considers the atmosphere as a plane-parallel absorbing and scattering medium where total, direct and diffuse spectral irradiance values are calculated at each level. Preliminary analysis shows promising results but the difficulty in modelling aerosol properties to fit experimental data is clearly manifested.

  13. Measurement of solar radiation

    SciTech Connect

    Braunstein, A.; Levite, T.; Sohar, E.

    1984-11-27

    There is provided a device for indicating the level of solar radiation intensity, and especially that region of the spectrum in the ultraviolet region which causes sunburn. The device may be provided with an output subdivided into a plurality of discrete levels of intensity indicated as numerals and figures. It may be provided with means of adjustment to the physiology of the user.

  14. SASKTRANIF- a New Engine for the Radiative Transfer Modeling of Solar Occultation Measurements.

    NASA Astrophysics Data System (ADS)

    Jones, A.; Lloyd, N.; Rieger, L. A.; Jensen, L.; Walker, K. A.; Degenstein, D. A.; Bourassa, A. E.; Boone, C. D.

    2014-12-01

    Vertical distributions of atmospheric gases measured by satellite instruments can be retrieved by mathematical inversion algorithms involving a forward model of the radiative transfer equation. Hence, an accurate forward model to predict atmospheric spectra is necessary for estimating volume mixing ratio quantities of these gases. One particular forward model is the SASKTRAN Inter-Face (or SASKTRANIF), which is a line by line radiative transfer model typically used to model atmospheric spectra arising from limb scattered sunlight at ultraviolet to near infrared wavelengths, using linear ray tracing and a three dimensional spherical shell atmosphere of homogeneous layers. An additional engine has now been implemented, designed to model solar occultation based measurements. Solar rays are traced through each atmospheric layer using an algorithm that accounts for refraction of the atmosphere. The extinction is calculated along the line of sight for a penetrating ray intersecting multiple layers of the atmosphere given a known chemical composition. By default, the engine uses the HITRAN 2008 spectral database to obtain information about the absorption cross sections of each modeled species, and also utilizes user defined climatologies for a priori information (such as input trace gas concentrations, temperature, and pressure). The new engine is currently in a testing phase. Here, we firstly compare synthesized spectra from SASKTRANIF with spectra derived from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) forward model. Secondly, we retrieve vertical volume mixing ratio profiles of various atmospheric gases by performing a global fit to ACE-FTS measured spectra where model parameters are determined using a Marquardt-Levenberg nonlinear least squares algorithm. Resulting vertical profiles are compared to those derived using the ACE-FTS retrieval system.

  15. Solar radiation in Jamaica

    SciTech Connect

    Chen, A.A.; Chin, P.N.; Forrest, W.; McLean, P. ); Grey, C. )

    1994-11-01

    Average monthly global radiation in Jamaica was calculated for the years between 1978 and 1987 from values measured at 12 stations and from Angstrom-coefficient derived values. From these values daily global radiation was estimated for various periods at grid points separated by approximately 10 km on a square. Three dimensional plots and contour maps for the various periods were produced. The interpolation was based on kriging adopted by Hay. A relationship between global and diffuse radiation based on the Liu and Jordan relationship was obtained. The errors in the interpolated annual values were less than 10%. The maps were made available to the public with suggested usages of solar energy. Diffuse radiation formed less than 50% of the total radiation.

  16. Modeling the ratio of photosynthetically active radiation to broadband global solar radiation using ground and satellite-based data in the tropics

    NASA Astrophysics Data System (ADS)

    Janjai, S.; Wattan, R.; Sripradit, A.

    2015-12-01

    Data from four stations in Thailand are used to model the ratio of photosynthetically active radiation (PAR) to broadband global solar radiation. The model expresses the ratio of PAR-to-broadband global solar radiation as a function of cloud index, aerosol optical depth, precipitable water, total ozone column and solar zenith angle. Data from the MTSAT-1R and OMI/AURA satellites are used to estimate the cloud index and total ozone column, respectively at each of the four stations, while aerosol optical depth and precipitable water are retrieved from Aerosol Robotic Network (AERONET) sunphotometer measurements, also available at each station. When tested against hourly measurements, the model exhibits a coefficient of variance (R2) equal to or better than 0.96, and root mean square difference (RMSD) in the range of 7.3-7.9% and mean bias difference (MBD) of -4.5% to 3.5%. The model compares favorably with other existing models.

  17. Radiation Effects Investigations Based on Atmospheric Radiation Model (ATMORAD) Considering GEANT4 Simulations of Extensive Air Showers and Solar Modulation Potential.

    PubMed

    Hubert, Guillaume; Cheminet, Adrien

    2015-07-01

    The natural radiative atmospheric environment is composed of secondary cosmic rays produced when primary cosmic rays hit the atmosphere. Understanding atmospheric radiations and their dynamics is essential for evaluating single event effects, so that radiation risks in aviation and the space environment (space weather) can be assessed. In this article, we present an atmospheric radiation model, named ATMORAD (Atmospheric Radiation), which is based on GEANT4 simulations of extensive air showers according to primary spectra that depend only on the solar modulation potential (force-field approximation). Based on neutron spectrometry, solar modulation potential can be deduced using neutron spectrometer measurements and ATMORAD. Some comparisons between our methodology and standard approaches or measurements are also discussed. This work demonstrates the potential for using simulations of extensive air showers and neutron spectroscopy to monitor solar activity. PMID:26151172

  18. A new analytical solar radiation pressure model for current BeiDou satellites: IGGBSPM.

    PubMed

    Tan, Bingfeng; Yuan, Yunbin; Zhang, Baocheng; Hsu, Hou Ze; Ou, Jikun

    2016-01-01

    An analytical solar radiation pressure (SRP) model, IGGBSPM (an abbreviation for Institute of Geodesy and Geophysics BeiDou Solar Pressure Model), has been developed for three BeiDou satellite types, namely, geostationary orbit (GEO), inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO), based on a ray-tracing method. The performance of IGGBSPM was assessed based on numerical integration, SLR residuals and analyses of empirical SRP parameters (except overlap computations). The numerical results show that the integrated orbit resulting from IGGBSPM differs from the precise ephemerides by approximately 5 m and 2 m for GEO and non-GEO satellites, respectively. Moreover, when IGGBSPM is used as an a priori model to enhance the ECOM (5-parameter) model with stochastic pulses, named ECOM + APR, for precise orbit determination, the SLR RMS residual improves by approximately 20-25 percent over the ECOM-only solution during the yaw-steering period and by approximately 40 percent during the yaw-fixed period. For the BeiDou GEO01 satellite, improvements of 18 and 32 percent can be achieved during the out-of-eclipse season and during the eclipse season, respectively. An investigation of the estimated ECOM D0 parameters indicated that the β-angle dependence that is evident in the ECOM-only solution is no longer present in the ECOM + APR solution. PMID:27595795

  19. A new analytical solar radiation pressure model for current BeiDou satellites: IGGBSPM

    PubMed Central

    Tan, Bingfeng; Yuan, Yunbin; Zhang, Baocheng; Hsu, Hou Ze; Ou, Jikun

    2016-01-01

    An analytical solar radiation pressure (SRP) model, IGGBSPM (an abbreviation for Institute of Geodesy and Geophysics BeiDou Solar Pressure Model), has been developed for three BeiDou satellite types, namely, geostationary orbit (GEO), inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO), based on a ray-tracing method. The performance of IGGBSPM was assessed based on numerical integration, SLR residuals and analyses of empirical SRP parameters (except overlap computations). The numerical results show that the integrated orbit resulting from IGGBSPM differs from the precise ephemerides by approximately 5 m and 2 m for GEO and non-GEO satellites, respectively. Moreover, when IGGBSPM is used as an a priori model to enhance the ECOM (5-parameter) model with stochastic pulses, named ECOM + APR, for precise orbit determination, the SLR RMS residual improves by approximately 20–25 percent over the ECOM-only solution during the yaw-steering period and by approximately 40 percent during the yaw-fixed period. For the BeiDou GEO01 satellite, improvements of 18 and 32 percent can be achieved during the out-of-eclipse season and during the eclipse season, respectively. An investigation of the estimated ECOM D0 parameters indicated that the β-angle dependence that is evident in the ECOM-only solution is no longer present in the ECOM + APR solution. PMID:27595795

  20. Acute hematological effects of solar particle event proton radiation in the porcine model.

    PubMed

    Sanzari, J K; Wan, X S; Wroe, A J; Rightnar, S; Cengel, K A; Diffenderfer, E S; Krigsfeld, G S; Gridley, D S; Kennedy, A R

    2013-07-01

    Acute radiation sickness (ARS) is expected to occur in astronauts during large solar particle events (SPEs). One parameter associated with ARS is the hematopoietic syndrome, which can result from decreased numbers of circulating blood cells in those exposed to radiation. The peripheral blood cells are critical for an adequate immune response, and low blood cell counts can result in an increased susceptibility to infection. In this study, Yucatan minipigs were exposed to proton radiation within a range of skin dose levels expected for an SPE (estimated from previous SPEs). The proton-radiation exposure resulted in significant decreases in total white blood cell count (WBC) within 1 day of exposure, 60% below baseline control value or preirradiation values. At the lowest level of the blood cell counts, lymphocytes, neutrophils, monocytes and eosinophils were decreased up to 89.5%, 60.4%, 73.2% and 75.5%, respectively, from the preirradiation values. Monocytes and lymphocytes were decreased by an average of 70% (compared to preirradiation values) as early as 4 h after radiation exposure. Skin doses greater than 5 Gy resulted in decreased blood cell counts up to 90 days after exposure. The results reported here are similar to studies of ARS using the nonhuman primate model, supporting the use of the Yucatan minipig as an alternative. In addition, the high prevalence of hematologic abnormalities resulting from exposure to acute, whole-body SPE-like proton radiation warrants the development of appropriate countermeasures to prevent or treat ARS occurring in astronauts during space travel. PMID:23672458

  1. Acute Hematological Effects of Solar Particle Event Proton Radiation in the Porcine Model

    PubMed Central

    Sanzari, J. K.; Wan, X. S.; Wroe, A. J.; Rightnar, S.; Cengel, K. A.; Diffenderfer, E. S.; Krigsfeld, G. S.; Gridley, D. S.; Kennedy, A. R.

    2013-01-01

    Acute radiation sickness (ARS) is expected to occur in astronauts during large solar particle events (SPEs). One parameter associated with ARS is the hematopoietic syndrome, which can result from decreased numbers of circulating blood cells in those exposed to radiation. The peripheral blood cells are critical for an adequate immune response, and low blood cell counts can result in an increased susceptibility to infection. In this study, Yucatan minipigs were exposed to proton radiation within a range of skin dose levels expected for an SPE (estimated from previous SPEs). The proton-radiation exposure resulted in significant decreases in total white blood cell count (WBC) within 1 day of exposure, 60% below baseline control value or preirradiation values. At the lowest level of the blood cell counts, lymphocytes, neutrophils, monocytes and eosinophils were decreased up to 89.5%, 60.4%, 73.2% and 75.5%, respectively, from the preirradiation values. Monocytes and lymphocytes were decreased by an average of 70% (compared to preirradiation values) as early as 4 h after radiation exposure. Skin doses greater than 5 Gy resulted in decreased blood cell counts up to 90 days after exposure. The results reported here are similar to studies of ARS using the nonhuman primate model, supporting the use of the Yucatan minipig as an alternative. In addition, the high prevalence of hematologic abnormalities resulting from exposure to acute, whole-body SPE-like proton radiation warrants the development of appropriate countermeasures to prevent or treat ARS occurring in astronauts during space travel. PMID:23672458

  2. Modelled and observed changes in aerosols and surface solar radiation over Europe between 1960 and 2009

    NASA Astrophysics Data System (ADS)

    Turnock, S. T.; Spracklen, D. V.; Carslaw, K. S.; Mann, G. W.; Woodhouse, M. T.; Forster, P. M.; Haywood, J.; Johnson, C. E.; Dalvi, M.; Bellouin, N.; Sanchez-Lorenzo, A.

    2015-08-01

    Substantial changes in anthropogenic aerosols and precursor gas emissions have occurred over recent decades due to the implementation of air pollution control legislation and economic growth. The response of atmospheric aerosols to these changes and the impact on climate are poorly constrained, particularly in studies using detailed aerosol chemistry-climate models. Here we compare the HadGEM3-UKCA (Hadley Centre Global Environment Model-United Kingdom Chemistry and Aerosols) coupled chemistry-climate model for the period 1960-2009 against extensive ground-based observations of sulfate aerosol mass (1978-2009), total suspended particle matter (SPM, 1978-1998), PM10 (1997-2009), aerosol optical depth (AOD, 2000-2009), aerosol size distributions (2008-2009) and surface solar radiation (SSR, 1960-2009) over Europe. The model underestimates observed sulfate aerosol mass (normalised mean bias factor (NMBF) = -0.4), SPM (NMBF = -0.9), PM10 (NMBF = -0.2), aerosol number concentrations (N30 NMBF = -0.85; N50 NMBF = -0.65; and N100 NMBF = -0.96) and AOD (NMBF = -0.01) but slightly overpredicts SSR (NMBF = 0.02). Trends in aerosol over the observational period are well simulated by the model, with observed (simulated) changes in sulfate of -68 % (-78 %), SPM of -42 % (-20 %), PM10 of -9 % (-8 %) and AOD of -11 % (-14 %). Discrepancies in the magnitude of simulated aerosol mass do not affect the ability of the model to reproduce the observed SSR trends. The positive change in observed European SSR (5 %) during 1990-2009 ("brightening") is better reproduced by the model when aerosol radiative effects (ARE) are included (3 %), compared to simulations where ARE are excluded (0.2 %). The simulated top-of-the-atmosphere aerosol radiative forcing over Europe under all-sky conditions increased by > 3.0 W m-2 during the period 1970-2009 in response to changes in anthropogenic emissions and aerosol concentrations.

  3. Modelled and observed changes in aerosols and surface solar radiation over Europe between 1960 and 2009

    NASA Astrophysics Data System (ADS)

    Turnock, S. T.; Spracklen, D. V.; Carslaw, K. S.; Mann, G. W.; Woodhouse, M. T.; Forster, P. M.; Haywood, J.; Johnson, C. E.; Dalvi, M.; Bellouin, N.; Sanchez-Lorenzo, A.

    2015-05-01

    Substantial changes in anthropogenic aerosols and precursor gas emissions have occurred over recent decades due to the implementation of air pollution control legislation and economic growth. The response of atmospheric aerosols to these changes and the impact on climate are poorly constrained, particularly in studies using detailed aerosol chemistry climate models. Here we compare the HadGEM3-UKCA coupled chemistry-climate model for the period 1960 to 2009 against extensive ground based observations of sulfate aerosol mass (1978-2009), total suspended particle matter (SPM, 1978-1998), PM10 (1997-2009), aerosol optical depth (AOD, 2000-2009) and surface solar radiation (SSR, 1960-2009) over Europe. The model underestimates observed sulfate aerosol mass (normalised mean bias factor (NMBF) = -0.4), SPM (NMBF = -0.9), PM10 (NMBF = -0.2) and aerosol optical depth (AOD, NMBF = -0.01) but slightly overpredicts SSR (NMBF = 0.02). Trends in aerosol over the observational period are well simulated by the model, with observed (simulated) changes in sulfate of -68% (-78%), SPM of -42% (-20%), PM10 of -9% (-8%) and AOD of -11% (-14%). Discrepancies in the magnitude of simulated aerosol mass do not affect the ability of the model to reproduce the observed SSR trends. The positive change in observed European SSR (5%) during 1990-2009 ("brightening") is better reproduced by the model when aerosol radiative effects (ARE) are included (3%), compared to simulations where ARE are excluded (0.2%). The simulated top-of-the-atmosphere aerosol radiative forcing over Europe under all-sky conditions increased by 3 W m-2 during the period 1970-2009 in response to changes in anthropogenic emissions and aerosol concentrations.

  4. An Enhanced Box-Wing Solar Radiation pressure model for BDS and initial results

    NASA Astrophysics Data System (ADS)

    Zhao, Qunhe; Wang, Xiaoya; Hu, Xiaogong; Guo, Rui; Shang, Lin; Tang, Chengpan; Shao, Fan

    2016-04-01

    Solar radiation pressure forces are the largest non-gravitational perturbations acting on GNSS satellites, which is difficult to be accurately modeled due to the complicated and changing satellite attitude and unknown surface material characteristics. By the end of 2015, there are more than 50 stations of the Multi-GNSS Experiment(MGEX) set-up by the IGS. The simple box-plate model relies on coarse assumptions about the dimensions and optical properties of the satellite due to lack of more detailed information. So, a physical model based on BOX-WING model is developed, which is more sophisticated and more detailed physical structure has been taken into account, then calculating pressure forces according to the geometric relations between light rays and surfaces. All the MGEX stations and IGS core stations had been processed for precise orbit determination tests with GPS and BDS observations. Calculation range covers all the two kinds of Eclipsing and non-eclipsing periods in 2015, and we adopted the un-differential observation mode and more accurate values of satellite phase centers. At first, we tried nine parameters model, and then eliminated the parameters with strong correlation between them, came into being five parameters of the model. Five parameters were estimated, such as solar scale, y-bias, three material coefficients of solar panel, x-axis and z-axis panels. Initial results showed that, in the period of yaw-steering mode, use of Enhanced ADBOXW model results in small improvement for IGSO and MEO satellites, and the Root-Mean-Square(RMS) error value of one-day arc orbit decreased by about 10%~30% except for C08 and C14. The new model mainly improved the along track acceleration, up to 30% while in the radial track was not obvious. The Satellite Laser Ranging(SLR) validation showed, however, that this model had higher prediction accuracy in the period of orbit-normal mode, compared to GFZ multi-GNSS orbit products, as well with relative post

  5. Toward a mathematical model of solar radiation for engineering analysis of solar energy systems

    NASA Technical Reports Server (NTRS)

    Hamilton, C. L.; Reid, M. S.

    1976-01-01

    The currently most-used insolation model and what improvements might be made in it to better suit it for use in designing energy systems is discussed. An approach to constructing an upgraded model is sketched.

  6. Day of the year-based prediction of horizontal global solar radiation by a neural network auto-regressive model

    NASA Astrophysics Data System (ADS)

    Gani, Abdullah; Mohammadi, Kasra; Shamshirband, Shahaboddin; Khorasanizadeh, Hossein; Seyed Danesh, Amir; Piri, Jamshid; Ismail, Zuraini; Zamani, Mazdak

    2015-06-01

    The availability of accurate solar radiation data is essential for designing as well as simulating the solar energy systems. In this study, by employing the long-term daily measured solar data, a neural network auto-regressive model with exogenous inputs (NN-ARX) is applied to predict daily horizontal global solar radiation using day of the year as the sole input. The prime aim is to provide a convenient and precise way for rapid daily global solar radiation prediction, for the stations and their immediate surroundings with such an observation, without utilizing any meteorological-based inputs. To fulfill this, seven Iranian cities with different geographical locations and solar radiation characteristics are considered as case studies. The performance of NN-ARX is compared against the adaptive neuro-fuzzy inference system (ANFIS). The achieved results prove that day of the year-based prediction of daily global solar radiation by both NN-ARX and ANFIS models would be highly feasible owing to the accurate predictions attained. Nevertheless, the statistical analysis indicates the superiority of NN-ARX over ANFIS. In fact, the NN-ARX model represents high potential to follow the measured data favorably for all cities. For the considered cities, the attained statistical indicators of mean absolute bias error, root mean square error, and coefficient of determination for the NN-ARX models are in the ranges of 0.44-0.61 kWh/m2, 0.50-0.71 kWh/m2, and 0.78-0.91, respectively.

  7. Day of the year-based prediction of horizontal global solar radiation by a neural network auto-regressive model

    NASA Astrophysics Data System (ADS)

    Gani, Abdullah; Mohammadi, Kasra; Shamshirband, Shahaboddin; Khorasanizadeh, Hossein; Seyed Danesh, Amir; Piri, Jamshid; Ismail, Zuraini; Zamani, Mazdak

    2016-08-01

    The availability of accurate solar radiation data is essential for designing as well as simulating the solar energy systems. In this study, by employing the long-term daily measured solar data, a neural network auto-regressive model with exogenous inputs (NN-ARX) is applied to predict daily horizontal global solar radiation using day of the year as the sole input. The prime aim is to provide a convenient and precise way for rapid daily global solar radiation prediction, for the stations and their immediate surroundings with such an observation, without utilizing any meteorological-based inputs. To fulfill this, seven Iranian cities with different geographical locations and solar radiation characteristics are considered as case studies. The performance of NN-ARX is compared against the adaptive neuro-fuzzy inference system (ANFIS). The achieved results prove that day of the year-based prediction of daily global solar radiation by both NN-ARX and ANFIS models would be highly feasible owing to the accurate predictions attained. Nevertheless, the statistical analysis indicates the superiority of NN-ARX over ANFIS. In fact, the NN-ARX model represents high potential to follow the measured data favorably for all cities. For the considered cities, the attained statistical indicators of mean absolute bias error, root mean square error, and coefficient of determination for the NN-ARX models are in the ranges of 0.44-0.61 kWh/m2, 0.50-0.71 kWh/m2, and 0.78-0.91, respectively.

  8. Radiative Transfer Modeling of the Enigmatic Scattering Polarization in the Solar Na I D1 Line

    NASA Astrophysics Data System (ADS)

    Belluzzi, Luca; Trujillo Bueno, Javier; Landi Degl'Innocenti, Egidio

    2015-12-01

    The modeling of the peculiar scattering polarization signals observed in some diagnostically important solar resonance lines requires the consideration of the detailed spectral structure of the incident radiation field as well as the possibility of ground level polarization, along with the atom's hyperfine structure and quantum interference between hyperfine F-levels pertaining either to the same fine structure J-level, or to different J-levels of the same term. Here we present a theoretical and numerical approach suitable for solving this complex non-LTE radiative transfer problem. This approach is based on the density-matrix metalevel theory (where each level is viewed as a continuous distribution of sublevels) and on accurate formal solvers of the transfer equations and efficient iterative methods. We show an application to the D-lines of Na i, with emphasis on the enigmatic D1 line, pointing out the observable signatures of the various physical mechanisms considered. We demonstrate that the linear polarization observed in the core of the D1 line may be explained by the effect that one gets when the detailed spectral structure of the anisotropic radiation responsible for the optical pumping is taken into account. This physical ingredient is capable of introducing significant scattering polarization in the core of the Na i D1 line without the need for ground-level polarization.

  9. Trend of surface solar radiation over Asia simulated by aerosol transport-climate model

    NASA Astrophysics Data System (ADS)

    Takemura, T.; Ohmura, A.

    2009-12-01

    Long-term records of surface radiation measurements indicate a decrease in the solar radiation between the 1950s and 1980s (“global dimming”), then its recovery afterward (“global brightening”) at many locations all over the globe [Wild, 2009]. On the other hand, the global brightening is delayed over the Asian region [Ohmura, 2009]. It is suggested that these trends of the global dimming and brightening are strongly related with a change in aerosol loading in the atmosphere which affect the climate change through the direct, semi-direct, and indirect effects. In this study, causes of the trend of the surface solar radiation over Asia during last several decades are analyzed with an aerosol transport-climate model, SPRINTARS. SPRINTARS is coupled with MIROC which is a general circulation model (GCM) developed by Center for Climate System Research (CCSR)/University of Tokyo, National Institute for Environmental Studies (NIES), and Frontier Research Center for Global Change (FRCGC) [Takemura et al., 2000, 2002, 2005, 2009]. The horizontal and vertical resolutions are T106 (approximately 1.1° by 1.1°) and 56 layers, respectively. SPRINTARS includes the transport, radiation, cloud, and precipitation processes of all main tropospheric aerosols (black and organic carbons, sulfate, soil dust, and sea salt). The model treats not only the aerosol mass mixing ratios but also the cloud droplet and ice crystal number concentrations as prognostic variables, and the nucleation processes of cloud droplets and ice crystals depend on the number concentrations of each aerosol species. Changes in the cloud droplet and ice crystal number concentrations affect the cloud radiation and precipitation processes in the model. Historical emissions, that is consumption of fossil fuel and biofuel, biomass burning, aircraft emissions, and volcanic eruptions are prescribed from database provided by the Aerosol Model Intercomparison Project (AeroCom) and the latest IPCC inventories

  10. Characterization of vegetation properties: Canopy modeling of pinyon-juniper and ponderosa pine woodlands; Final report. Modeling topographic influences on solar radiation: A manual for the SOLARFLUX model

    SciTech Connect

    Rich, P.M.; Hetrick, W.A.; Saving, S.C.

    1994-12-31

    This report is comprised of two studies. The first study focuses on plant canopies in pinyon-juniper woodland, ponderosa pine woodland, and waste sites at Los Alamos National Laboratory which involved five basic areas of research: (1) application of hemispherical photography and other gap fraction techniques to study solar radiation regimes and canopy architecture, coupled with application of time-domain reflectometry to study soil moisture; (2) detailed characterization of canopy architecture using stand mapping and allometry; (3) development of an integrated geographical information system (GIS) database for relating canopy architecture with ecological, hydrological, and system modeling approaches; (4) development of geometric models that simulate complex sky obstruction, incoming solar radiation for complex topographic surfaces, and the coupling of incoming solar radiation with energy and water balance, with simulations of incoming solar radiation for selected native vegetation and experimental waste cover design sites; and (5) evaluation of the strengths and limitations of the various field sampling techniques. The second study describes an approach to develop software that takes advantage of new generation computers to model insolation on complex topographic surfaces. SOLARFLUX is a GIS-based (ARC/INFO, GRID) computer program 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. This manual serves as the comprehensive guide to SOLARFLUX. Included are discussions on modelling insolation on complex surfaces, the theoretical approach, program setup and operation, and a set of applications illustrating characteristics of topographic insolation modelling.

  11. An influence of solar activity on latitudinal distribution of atmospheric ozone and temperature in 2-D radiative-photochemical model

    NASA Technical Reports Server (NTRS)

    Dyominov, I. G.

    1989-01-01

    On the basis of the 2-D radiative-photochemical model of the ozone layer at heights 0 to 60 km in the Northern Hemisphere there are revealed and analyzed in detail the characteristic features of the season-altitude-latitude variations of ozone and temperature due to changes of the solar flux during the 11 year cycle, electron and proton precipitations.

  12. Solar radiation on Mars: Update 1990

    NASA Technical Reports Server (NTRS)

    Appelbaum, Joseph; Flood, Dennis J.

    1990-01-01

    Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. The authors present a procedure and solar radiation related data from which the diurnally and daily variation of the global, direct beam and diffuse insolation on Mars are calculated. The radiation data are based on measured optical depth of the Martian atmosphere derived from images taken of the Sun with a special diode on the Viking Lander cameras and computation based on multiple wavelength and multiple scattering of the solar radiation. This work is an update to NASA-TM-102299 and includes a refinement of the solar radiation model.

  13. Modelling solar radiation reached to the Earth using ANFIS, NN-ARX, and empirical models (Case studies: Zahedan and Bojnurd stations)

    NASA Astrophysics Data System (ADS)

    Piri, Jamshid; Kisi, Ozgur

    2015-02-01

    The amount of incoming solar energy that crosses the Earth's atmosphere is called solar radiation. The solar radiation is a series of ultraviolet wavelengths including visible and infrared light. The solar rays at the Earth's surface is one of the key factor in water resources, environmental and agricultural modelling. Solar radiation is rarely measured by weather stations in Iran and other developing countries; as a result, many empirical approaches have been applied to estimate it by using other climatic parameters. In this study, non-linear models, adaptive neuro-fuzzy inference system (ANFIS) and neural network auto-regressive model with exogenous inputs (NN-ARX) along with empirical models, Angstrom and Hargreaves-Samani, have been used to estimate the solar radiation. The data was collected from two synoptic stations with different climatic conditions (Zahedan and Bojnurd) during the period of 5 and 7 years, respectively. These data contain sunshine hours, maximum temperature, minimum temperature, average relative humidity and solar radiation. The Angstrom and Hargreaves-Samani empirical models, respectively, based on sunshine hours and temperature were calibrated and evaluated in both stations. In order to train, test, and validate ANFIS and NNRX models, 60%, 25%, and 15% of the data were applied, respectively. The results of artificial intelligence models were compared with the empirical models. The findings showed that ANFIS (R2=0.90 and 0.97 for Zahedan and Bojnurd, respectively) and NN-ARX (R2=0.89 and 0.96 for Zahedan and Bojnurd, respectively) performed better than the empirical models in estimating daily solar radiation.

  14. Methods to Estimate Solar Radiation Dosimetry in Coral Reefs Using Remote Sensed, Modeled, and in Situ Data.

    EPA Science Inventory

    Solar irradiance has been increasingly recognized as an important determinant of bleaching in coral reefs, but measurements of solar radiation exposure within coral reefs have been relatively limited. Solar irradiance and diffuse down welling attenuation coefficients (Kd, m-1) we...

  15. GIOVE-B solar radiation pressure modeling for precise orbit determination

    NASA Astrophysics Data System (ADS)

    Steigenberger, Peter; Montenbruck, Oliver; Hugentobler, Urs

    2015-03-01

    Previous studies have identified systematic errors in the orbit and clock estimates of the GIOVE and Galileo IOV satellites in the order of ± 20 cm. These errors are visible as periodic variations in the Satellite Laser Ranging (SLR) and clock residuals. For IOV, these variations could be attributed to the contribution of a stretched satellite body and it was shown that a simple a priori box model for the solar radiation pressure can significantly reduce these errors. GIOVE-B has similar dimensions as the IOV satellites but its orientation is different: for GIOVE-B the narrow side of the satellite points to the Earth rather than the longitudinal side. In addition, an extra plate carrying, amongst others, the laser retro reflector array is mounted on the spacecraft introducing shadowing effects. These features are considered with a simple box-plate model. This model reduces the periodic clock errors and the SLR residual RMS of GIOVE-B by a factor of two. Most importantly, the box-plate model reduces the SLR offset from 11 cm to less than 1 cm. The largest part of this reduction comes from considering the plate and its shadowing effects.

  16. Simple device measures solar radiation

    NASA Technical Reports Server (NTRS)

    Humphries, W. R.

    1977-01-01

    Simple inexpensive thermometer, insolated from surroundings by transparent glass or plastic encasement, measures intensities of solar radiation, or radiation from other sources such as furnaces or ovens. Unit can be further modified to accomplish readings from remote locations.

  17. Solar flare particle radiation

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.

    1972-01-01

    The characteristics of the solar particles accelerated by solar flares and subsequently observed near the orbit of the earth are studied. Considered are solar particle intensity-time profiles, the composition and spectra of solar flare events, and the propagation of solar particles in interplanetary space. The effects of solar particles at the earth, riometer observations of polar cap cosmic noise absorption events, and the production of solar cell damage at synchronous altitudes by solar protons are also discussed.

  18. A new empirical solar radiation pressure model for BeiDou GEO satellites

    NASA Astrophysics Data System (ADS)

    Liu, Junhong; Gu, Defeng; Ju, Bing; Shen, Zhen; Lai, Yuwang; Yi, Dongyun

    2016-01-01

    Two classic empirical solar radiation pressure (SRP) models, the Extended Center for Orbit Determination in Europe (CODE) Orbit Model ECOM 5 and ECOM 9 have been widely used for Global Positioning System (GPS) Medium Earth Orbit (MEO) satellites precise orbit determination (POD). However, these two models are not suitable for BeiDou Geostationary Earth Orbit (GEO) satellites due to their special attitude control mode. With the experimental design method this paper proposes a new empirical SRP model for BeiDou GEO satellites, which is featured by three constant terms in DYX directions, two sine terms in DX directions and one cosine term in the Y direction. It is the first time to reveal that the periodic terms in the D direction are more important than those in YX directions for BeiDou GEO satellites. Compared with ECOM 5 and ECOM 9, the BeiDou GEO satellite orbits are significantly stabilized with the new SRP force model. The average orbit overlapping root mean square (RMS) achieved by the proposed model is 7.5 cm in the radial component, which is evidently improved over those of 37.4 and 13.2 cm for ECOM 5 and ECOM 9, respectively. In addition, the correlation coefficients between GEO orbit overlaps precision and the elevation angle of the Sun have been decreased to -0.12, 0.21, and -0.03 in radial, along-track and cross-track components by using the proposed model, while they are -0.94, -0.79 and -0.29 for ECOM 5 and -0.70, 0.21 and 0.10 for ECOM 9. Moreover, the standard deviation (STD) of Satellite Laser Ranging (SLR) data residuals for the GEO satellite C01 is reduced by 37.4% and 16.1% compared with those of ECOM 5 and ECOM 9 SRP models.

  19. Solar Radiation Measurements at the Chesapeake Bay COVE Site and Comparison With Model

    NASA Astrophysics Data System (ADS)

    Jin, Z.; Charlock, T.; Rutledge, K.

    2001-05-01

    To validate retrievals of flux and albedo in the CERES satellite program, broad-band upwelling and downwelling solar irradiances are measured routinely at the CERES Ocean Validation Experiment (COVE) site 25 km east of the coast of Virginia, near the mouth of the Chesapeake Bay. A full year of observations are compared with simulations from a coupled radiative transfer model. The coupled model treats absorption and scattering by layers of both the atmosphere and the ocean explicitly and consistently, in terms of the inherent optical properties of the air and the sea. Key input parameters for the model include aerosol optical depth, wind speed, and total precipitable water; these are measured at COVE. The modeled total downwelling irradiances, which depend mainly on the atmospheric optical properties, agree well with observations. But the modeled upwelling irradiances (and hence ocean surface albedo), which depend heavily on the the ocean optical properties, are generally less than the observations. The measured upwelling irradiances are strongly influenced by sea state and surface wind, resulting in a seasonal variation of the ocean surface albedo. Candidates to explain the discrepancy of observed and modeled albedo are (1) in-ocean scattering that was not included in the model (i.e., sediments or air bubbles), (2) possible inadequacy of the classical Cox-Munk distribution for the wind speed dependence of sea slopes, and (3) uncertainties in aerosol optical properties. We are presently testing SeaWiFS data as a source for the concentrations of chlorophyl and dissolved organic matter (DOM); and plan to compare the model with available upwelling spectral irradiances and radiances, in addition to the broadband fluxes as described above.

  20. Effects of the partitioning of diffuse and direct solar radiation on satellite-based modeling of crop gross primary production

    NASA Astrophysics Data System (ADS)

    Xin, Qinchuan; Gong, Peng; Suyker, Andrew E.; Si, Yali

    2016-08-01

    Modeling crop gross primary production (GPP) is critical to understanding the carbon dynamics of agro-ecosystems. Satellite-based studies have widely used production efficiency models (PEM) to estimate cropland GPP, wherein light use efficiency (LUE) is a key model parameter. One factor that has not been well considered in many PEMs is that canopy LUE could vary with illumination conditions. This study investigates how the partitioning of diffuse and direct solar radiation influences cropland GPP using both flux tower and satellite data. The field-measured hourly LUE under cloudy conditions was 1.50 and 1.70 times higher than that under near clear-sky conditions for irrigated corn and soybean, respectively. We applied a two-leaf model to simulate the canopy radiative transfer process, where modeled photosynthetically active radiation (PAR) absorbed by canopy agreed with tower measurements (R2 = 0.959 and 0.914 for corn and soybean, respectively). Derived canopy LUE became similar after accounting for the impact of light saturation on leaf photosynthetic capacity under varied illumination conditions. The impacts of solar radiation partitioning on satellite-based modeling of crop GPP was examined using vegetation indices (VI) derived from MODIS data. Consistent with the field modeling results, the relationship between daily GPP and PAR × VI under varied illumination conditions showed different patterns in terms of regression slope and intercept. We proposed a function to correct the influences of direct and diffuse radiation partitioning and the explained variance of flux tower GPP increased in all experiments. Our results suggest that the non-linear response of leaf photosynthesis to light absorption contributes to higher canopy LUE on cloudy days than on clear days. We conclude that accounting for the impacts of solar radiation partitioning is necessary for modeling crop GPP on a daily or shorter basis.

  1. Reduction of Solar UV Radiation Due to Urban High-Rise Buildings – A Coupled Modelling Study

    PubMed Central

    Wai, Ka-Ming; Yu, Peter K. N.; Lam, Ka-Se

    2015-01-01

    Solar UV radiation has both adverse and beneficial effects to human health. Using models (a radiative transfer model coupled to a building shading model), together with satellite and surface measurements, we studied the un-obstructed and obstructed UV environments in a sub-tropical urban environment featured with relatively high pollution (aerosol) loadings and high-rise buildings. Seasonal patterns of the erythemal UV exposure rates were governed by solar zenith angles, seasonal variations of aerosol loadings and cloud effects. The radiative transfer modelling results agreed with measurements of erythemal UV exposure rates and spectral irradiances in UVA and UVB ranges. High-rise buildings and narrow road width (height to width, H/W, ratios up to 15) reduced the modelled total UV (UVA+UVB) radiation and leave 10% of the un-obstructed exposure rate at ground-level at noon. No more than 80% of the un-obstructed exposure rate was received in the open area surrounded by 20-storey buildings. Our modelled reduction of UVB radiation in the urban environment was consistent with similar measurements obtained for Australia. However, our results in more extreme environments (higher H/W ratios) were for the first time reported, with 18% of the un-obstructed exposure rate remained at the ground-level center of the street canyon. PMID:26263507

  2. Modeling polarized solar radiation for CLARREO inter-calibration applications: Validation with PARASOL data

    NASA Astrophysics Data System (ADS)

    Sun, Wenbo; Lukashin, Constantine; Baize, Rosemary R.; Goldin, Daniel

    2015-01-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) is a high-priority NASA Decadal Survey mission recommended by the National Research Council in 2007. The CLARREO objectives are to conduct highly accurate decadal climate-change observations and to provide an on-orbit inter-calibration standard for relevant Earth observing sensors. The inter-calibration approach is based on providing highly accurate spectral reflectance measurements from the CLARREO Reflected Solar Spectrometer (RSS) as the reference for existing sensors and to monitor and characterize their response function parameters including gain, offset, non-linearity, optics spectral response, and sensitivity to polarization of light. The inter-calibration of instrument sensitivity to polarization requires on-orbit knowledge of polarization state of light as function of observed scene type and viewing geometry. In this study, we validate polarization parameters calculated with the adding-doubling radiative transfer model (ADRTM) for developing the Polarization Distribution Models (PDMs). These model results are compared with observations from the Polarization and Anisotropy of Reflectances for Atmospheric Science instrument coupled with Observations from a Lidar (PARASOL) data. Good agreement between model results and satellite data is shown for both liquid water clouds and ice clouds. Difference between model results and satellite measurements for clear-sky oceans is explained as due to the presence of undetected clouds, that are super-thin or whose spatial and temporal mean optical depth is small, in the PARASOL clear-sky scenes. These results demonstrate that the ADRTM provides a reliable approach for building spectral PDMs for the inter-calibration applications of the CLARREO mission.

  3. Solar Atmosphere Models

    NASA Astrophysics Data System (ADS)

    Rutten, R. J.

    2002-12-01

    This contribution honoring Kees de Jager's 80th birthday is a review of "one-dimensional" solar atmosphere modeling that followed on the initial "Utrecht Reference Photosphere" of Heintze, Hubenet & de Jager (1964). My starting point is the Bilderberg conference, convened by de Jager in 1967 at the time when NLTE radiative transfer theory became mature. The resulting Bilderberg model was quickly superseded by the HSRA and later by the VAL-FAL sequence of increasingly sophisticated NLTE continuum-fitting models from Harvard. They became the "standard models" of solar atmosphere physics, but Holweger's relatively simple LTE line-fitting model still persists as a favorite of solar abundance determiners. After a brief model inventory I discuss subsequent work on the major modeling issues (coherency, NLTE, dynamics) listed as to-do items by de Jager in 1968. The present conclusion is that one-dimensional modeling recovers Schwarzschild's (1906) finding that the lower solar atmosphere is grosso modo in radiative equilibrium. This is a boon for applications regarding the solar atmosphere as one-dimensional stellar example - but the real sun, including all the intricate phenomena that now constitute the mainstay of solar physics, is vastly more interesting.

  4. A Comparison of Satellite Based, Modeled Derived Daily Solar Radiation Data with Observed Data for the Continental US

    NASA Technical Reports Server (NTRS)

    White, Jeffrey W.; Hoogenboom, Gerrit; Wilkens, Paul W.; Stackhouse, Paul W., Jr.; Hoell, James M.

    2010-01-01

    Many applications of simulation models and related decision support tools for agriculture and natural resource management require daily meteorological data as inputs. Availability and quality of such data, however, often constrain research and decision support activities that require use of these tools. Daily solar radiation (SRAD) data are especially problematic because the instruments require electronic integrators, accurate sensors are expensive, and calibration standards are seldom available. The Prediction Of Worldwide Energy Resources (NASA/POWER; power.larc.nasa.gov) project at the NASA Langley Research Center estimates daily solar radiation based on data that are derived from satellite observations of outgoing visible radiances and atmospheric parameters based upon satellite observations and assimilation models. The solar data are available for a global 1 degree x 1 degree coordinate grid. SRAD can also be estimated based on attenuation of extraterrestrial radiation (Q0) using daily temperature and rainfall data to estimate the optical thickness of the atmosphere. This study compares daily solar radiation data from NASA/POWER (SRADNP) with instrument readings from 295 stations (SRADOB), as well as with values that were estimated with the WGENR solar generator. WGENR was used both with daily temperature and precipitation records from the stations reporting solar data and records from the NOAA Cooperative Observer Program (COOP), thus providing two additional sources of solar data, SRADWG and SRADCO. Values of SRADNP for different grid cells consistently showed higher correlations (typically 0.85 to 0.95) with SRADOB data than did SRADWG or SRADCO for sites within the corresponding cells. Mean values of SRADOB, SRADWG and SRADNP for sites within a grid cell usually were within 1 MJm-2d-1 of each other, but NASA/POWER values averaged 1.1 MJm-2d-1 lower than SRADOB. The magnitude of this bias was greater at lower latitudes and during summer months and may be at

  5. Image formation mechanism on the Shroud of Turin: a solar reflex radiation model (the optical aspect).

    PubMed

    Mouraviev, S N

    1997-12-01

    Unprejudiced logical analysis of the main available data, in the first instance, those collected in 1978 by the American interdisciplinary team known as STURP, suggests that the image of the dead man on the Shroud of Turin resulted from (a) the reflection by the anointed body of transmitted solar rays and their projection onto the inner side of the cloth and (b) the chemical registration of this reflex image by the topmost fibers of the linen, probably with a water or oil solution of aloes and myrrh acting as a catalyzer. This reflex radiation model requires the following: (1) action at the shortest possible distance (i.e., a maximum clinging of the Shroud to the body except for a narrow intervening liquid film), which explains the high resolution and the absence of serious distortions, and (2) double exposure-of both the face and the back-of the enveloped corpse to the sun, which accounts for the presence and optical symmetry of both the frontal and the dorsal images. An attempt is also made to reinterpret the so-called three-dimensional information encoded in the image. Although some chemical issues are also mentioned and a historical reconstruction of the burial procedure is suggested, first and foremost the optical aspect of this mechanism is addressed here. PMID:18264452

  6. Geometrical Model of Solar Radiation Pressure Based on High-Performing Galileo Clocks - First Geometrical Mapping of the Yarkowsky effect

    NASA Astrophysics Data System (ADS)

    Svehla, Drazen; Rothacher, Markus; Hugentobler, Urs; Steigenberger, Peter; Ziebart, Marek

    2014-05-01

    Solar radiation pressure is the main source of errors in the precise orbit determination of GNSS satellites. All deficiencies in the modeling of Solar radiation pressure map into estimated terrestrial reference frame parameters as well as into derived gravity field coefficients and altimetry results when LEO orbits are determined using GPS. Here we introduce a new approach to geometrically map radial orbit perturbations of GNSS satellites using highly-performing clocks on board the first Galileo satellites. Only a linear model (time bias and time drift) needs to be removed from the estimated clock parameters and the remaining clock residuals map all radial orbit perturbations along the orbit. With the independent SLR measurements, we show that a Galileo clock is stable enough to map radial orbit perturbations continuously along the orbit with a negative sign in comparison to SLR residuals. Agreement between the SLR residuals and the clock residuals is at the 1 cm RMS for an orbit arc of 24 h. Looking at the clock parameters determined along one orbit revolution over a period of one year, we show that the so-called SLR bias in Galileo and GPS orbits can be explained by the translation of the determined orbit in the orbital plane towards the Sun. This orbit translation is due to thermal re-radiation and not accounting for the Sun elevation in the parameterization of the estimated Solar radiation pressure parameters. SLR ranging to GNSS satellites takes place typically at night, e.g. between 6 pm and 6 am local time when the Sun is in opposition to the satellite. Therefore, SLR observes only one part of the GNSS orbit with a negative radial orbit error that is mapped as an artificial bias in SLR observables. The Galileo clocks clearly show orbit translation for all Sun elevations: the radial orbit error is positive when the Sun is in conjuction (orbit noon) and negative when the Sun is in opposition (orbit midnight). The magnitude of this artificial negative SLR bias

  7. A Model of Solar Radiation and Joule Heating in Flow of Third Grade Nanofluid

    NASA Astrophysics Data System (ADS)

    Hussain, Tariq; Hayat, Tasawar; Shehzad, Sabir Ali; Alsaedi, Ahmed; Chen, Bin

    2015-03-01

    The flow problem resulting from the stretching of a surface with convective conditions in a magnetohydrodynamic nanofluid with solar radiation is examined. Both heat and nanoparticle mass transfer convective conditions are employed. An incompressible third grade fluid which exhibits shear thinning and shear thickening characteristics is used as a base fluid. Concept of convective nanoparticle mass condition is introduced. Effects of Brownian motion and thermophoresis on magnetohydrodynamic flow of nanofluid are accounted in the presence of thermal radiation. Energy equation incorporates the features of Joule heating. The impact of physical parameters on the temperature and nanoparticle concentration has been pointed out. Numerical values of skin-friction coefficient are presented and analysed. It is hoped that this present investigation serves as a stimulus for the next generation of solar film collectors, heat exchangers technology, material processing, geothermal energy storage, and all those processes which are highly affected by the heat enhancement concept.

  8. Numerical modeling of radiation effects in Si solar cell for space

    NASA Astrophysics Data System (ADS)

    Fedoseyev, Alexandre; Raman, Ashok; Thomas, David; Bowden, Stuart; Choi, Jea Young; Honsberg, Christiana; Monga, Tanmay

    2015-03-01

    Improvements to solar cell efficiency and radiation hardness that are compatible with low cost, high volume manufacturing processes are critical for power generation applications in future long-term NASA and DOD space missions. In this paper, we provide the results of numerical simulation of the radiation effects in a novel, ultra-thin (UT), Si photovoltaic cell technology that combines enhanced light trapping (LT) and absorption due to nanostructured surfaces, separation of photogenerated carriers by carrier selective contacts (CSC), and increased carrier density due to multiple exciton generation (MEG). Such solar cells have a potential to achieve high conversion efficiencies while shown to be rad-hard, lightweight, flexible, and low-cost, due to the use of Si high volume techniques.

  9. Radiation hydrodynamics in solar flares

    SciTech Connect

    Fisher, G.H.

    1985-10-18

    Solar flares are rather violent and extremely complicated phenomena, and it should be made clear at the outset that a physically complete picture describing all aspects of flares does not exist. From the wealth of data which is available, it is apparent that many different types of physical processes are involved during flares: energetic particle acceleration, rapid magnetohydrodynamic motion of complex field structures, magnetic reconnection, violent mass motion along magnetic field lines, and the heating of plasma to tens of millions of degrees, to name a few. The goal of this paper is to explore just one aspect of solar flares, namely, the interaction of hydrodynamics and radiation processes in fluid being rapidly heated along closed magnetic field lines. The models discussed are therefore necessarily restrictive, and will address only a few of the observed or observable phenomena. 46 refs., 6 figs.

  10. Utilization of solar radiation by polar animals: an optical model for pelts.

    PubMed

    Grojean, R E; Sousa, J A; Henry, M C

    1980-02-01

    A summary of existing passive solar-heat conversion panels provides the basis for a definition of an ideal passive solar-heat converter. Evidence for the existence of a biological greenhouse effect in certain homopolar homeothermic species is reviewed. The thermal and optical properties of homeothermic pelts, in particular those of the polar bear, are described, and a qualitative optical model of the polar bear pelt is proposed. The effectiveness of polar bear and seal pelts as solar-heat converters is discussed, and comparison is made with the ideal converter. PMID:20216852

  11. Utilization of solar radiation by polar animals: an optical model for pelts

    SciTech Connect

    Grojean, R.E.; Sousa, J.A.; Henry, M.C.

    1980-02-01

    A summary of existing passive solar-heat conversion panels provides the basis for a definition of an ideal passive solar-heat converter. Evidence for the existence of a biological greenhouse effect in certain homopolar homeothermic species is reviewed. The thermal and optical properties of homeothermic pelts, in particular those of the polar bear, are described, and a qualitative optical model of the polar bear pelt is proposed. The effectiveness of polar bear and seal pelts as solar-heat converters is discussed, and comparison is made with the ideal converter.

  12. Modeling the impacts of solar radiation partitioning into direct and diffuse fractions for the global water cycle

    NASA Astrophysics Data System (ADS)

    Oliveira, Paulo J. C.; Davin, Edouard L.; Seneviratne, Sonia I.

    2010-05-01

    Incident solar radiation at the Earth's surface affects plant photosynthesis and evapotranspiration, and consequently the global water budget. Observations from 1960-1990's across the Northern Hemisphere suggest that increased aerosol loadings from industrialization led not only to a decline in the intensity of solar radiation at the surface (global dimming), but also to a higher fraction of scattered light, which enhanced plant photosynthesis and the land carbon sink, with probable concurrent impacts on the water cycle. Thus, we used the NCAR Community Land Model (version 3.5) to perform global offline simulations and study the effects of the imposition of changes to radiation partitioning in diffuse and direct fractions on trends in evapotranspiration and runoff. We find that most modeled land surface variables respond to an increased-diffuse simulation where the relative fraction of radiation is changed globally at a high rate of increased diffuse as reported by some observation stations. Increased-diffuse partitioning causes a rise in total ET in all regions, an effect of opposite sign but smaller absolute value than that resulting from global dimming. Evapotranspiration rises by over 0.5 watt/m2 per decade in the tropics, due to increased shaded leaf stomatal conductance, with an opposite effect noted elsewhere due to lower ground evaporation. In the eastern U.S.A. and the Amazon basin, decadal trend anomalies in evapotranspiration for increased-diffuse radiation change reach 25-30% the absolute magnitude of those caused by dimming. Reductions to river runoff are modest nearly everywhere outside the Amazon. Understanding the mechanisms behind the interactions between solar radiation and the various land-surface components will help the development of climate models, improving predictions, in particular regarding changes in terrestrial hydrologic resources.

  13. Solar radiation absorbing material

    DOEpatents

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  14. Solar radiation management impacts on agriculture in China: A case study in the Geoengineering Model Intercomparison Project (GeoMIP)

    NASA Astrophysics Data System (ADS)

    Xia, Lili; Robock, Alan; Cole, Jason; Curry, Charles L.; Ji, Duoying; Jones, Andy; Kravitz, Ben; Moore, John C.; Muri, Helene; Niemeier, Ulrike; Singh, Balwinder; Tilmes, Simone; Watanabe, Shingo; Yoon, Jin-Ho

    2014-07-01

    Geoengineering via solar radiation management could affect agricultural productivity due to changes in temperature, precipitation, and solar radiation. To study rice and maize production changes in China, we used results from 10 climate models participating in the Geoengineering Model Intercomparison Project (GeoMIP) G2 scenario to force the Decision Support System for Agrotechnology Transfer (DSSAT) crop model. G2 prescribes an insolation reduction to balance a 1% a-1 increase in CO2 concentration (1pctCO2) for 50 years. We first evaluated the DSSAT model using 30 years (1978-2007) of daily observed weather records and agriculture practices for 25 major agriculture provinces in China and compared the results to observations of yield. We then created three sets of climate forcing for 42 locations in China for DSSAT from each climate model experiment: (1) 1pctCO2, (2) G2, and (3) G2 with constant CO2 concentration (409 ppm) and compared the resulting agricultural responses. In the DSSAT simulations: (1) Without changing management practices, the combined effect of simulated climate changes due to geoengineering and CO2 fertilization during the last 15 years of solar reduction would change rice production in China by -3.0 ± 4.0 megaton (Mt) (2.4 ± 4.0%) as compared with 1pctCO2 and increase Chinese maize production by 18.1 ± 6.0 Mt (13.9 ± 5.9%). (2) The termination of geoengineering shows negligible impacts on rice production but a 19.6 Mt (11.9%) reduction of maize production as compared to the last 15 years of geoengineering. (3) The CO2 fertilization effect compensates for the deleterious impacts of changes in temperature, precipitation, and solar radiation due to geoengineering on rice production, increasing rice production by 8.6 Mt. The elevated CO2 concentration enhances maize production in G2, contributing 7.7 Mt (42.4%) to the total increase. Using the DSSAT crop model, virtually all of the climate models agree on the sign of the responses, even though

  15. Orbit Stability of OSIRIS-REx in the Vicinity of Bennu Using a High-Fidelity Solar Radiation Model

    NASA Technical Reports Server (NTRS)

    Williams, Trevor; Hughes, Kyle; Mashiku, Alinda; Longuski, James

    2015-01-01

    The OSIRIS-REx mission (Origins Spectral Interpretation Resource Identification Security Regolith EXPlorer) is an asteroid sample return mission to Bennu (RQ36) that is scheduled to launch in 2016. The planned science operations precluding the small retrieval involve operations in terminator orbits (orbit plane is perpendicular to the sun). Over longer durations the solar radiation pressure (SRP) perturbs the orbit causing it to precess. Our work involves: modeling high fidelity SRP model to capture the perturbations during attitude changes; design a stable orbit from the high fidelity models to analyze the stability over time.

  16. Solar and thermal radiation in the Venus atmosphere

    NASA Technical Reports Server (NTRS)

    Moroz, V. I.; Ekonomov, A. P.; Moshkin, B. E.; Revercomb, H. E.; Sromovsky, L. A.; Schofield, J. T.

    1985-01-01

    Attention is given to the solar and thermal radiation fields of Venus. Direct measurements and the results of numerical models based on direct measurements are presented. Radiation outside the atmosphere is considered with emphasis placed on global energy budget parameters, spectral and angular dependences, spatial distribution, and temporal variations of solar and thermal radiation. Radiation fluxes inside the atmosphere below 90 km are also considered with attention given to the solar flux at the surface, solar and thermal radiation fluxes from 100 km to the surface, and radiative heating and cooling below 100 km.

  17. A model for absorption of solar radiation by mineral dust within liquid cloud drops

    NASA Astrophysics Data System (ADS)

    Zhang, Qing; Thompson, Jonathan E.

    2015-10-01

    Models of light scattering and absorption that consider the effect of insoluble inclusions present within liquid cloud droplets may assume the inclusion occupies random locations within the droplet. In certain cases, external forces can lead to certain orientations or alignments that are strongly preferred. Within this modeling study, we consider one such case in which an insoluble mineral dust inclusion (ρ=2.6 g/cm3) is placed within a liquid water drop (ρ=1.0 g/cm3). Such an instance mimics mineral dust aerosols being incorporated within cloud drops in Earth's atmosphere. Model results suggest super-micron mineral dust settles to the bottom of cloud droplets. However, Brownian motion largely randomizes the position of sub-micron mineral dust within the droplet. The inherent organization of the particles that result has important consequences for light absorption by mineral dust when present within a cloud drop. Modeled results suggest light absorption efficiency may be enhanced by as much as 4-6 fold for an isolated droplet experiencing direct solar illumination at solar zenith angles of <20°. For such an isolated droplet, the absorption efficiency enhancement falls rapidly with increasing solar zenith angle indicating a strong angle of incidence dependence. We also consider the more common case of droplets that contain dust inclusions deep within optically dense clouds. Absorption efficiency enhancements for these locales follow a dramatically different pattern compared to the optically isolated droplet due to the presence of diffuse rather than direct solar irradiation. In such cases, light absorption efficiency is decreased through including super-micron dust within water droplets. The study has important implications for modeling the absorption of sunlight by mineral dust aerosol within liquid water clouds. The angle of incidence dependence also reveals that experimental measurement of light absorption for cases in which particle alignment occurs may not

  18. A computation ANN model for quantifying the global solar radiation: A case study of Al-Aqabah-Jordan

    NASA Astrophysics Data System (ADS)

    Abolgasem, I. M.; Alghoul, M. A.; Ruslan, M. H.; Chan, H. Y.; Khrit, N. G.; Sopian, K.

    2015-09-01

    In this paper, a computation model is developed to predict the global solar radiation (GSR) in Aqaba city based on the data recorded with association of Artificial Neural Networks (ANN). The data used in this work are global solar radiation (GSR), sunshine duration, maximum & minimum air temperature and relative humidity. These data are available from Jordanian meteorological station over a period of two years. The quality of GSR forecasting is compared by using different Learning Algorithms. The decision of changing the ANN architecture is essentially based on the predicted results to obtain the best ANN model for monthly and seasonal GSR. Different configurations patterns were tested using available observed data. It was found that the model using mainly sunshine duration and air temperature as inputs gives accurate results. The ANN model efficiency and the mean square error values show that the prediction model is accurate. It is found that the effect of the three learning algorithms on the accuracy of the prediction model at the training and testing stages for each time scale is mostly within the same accuracy range.

  19. Solar irradiance short wave radiation users guide

    NASA Astrophysics Data System (ADS)

    Martinolich, Paul; Arnone, Robert A.

    1995-05-01

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

  20. GaAs Solar Cell Radiation Handbook

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.

    1996-01-01

    History of GaAs solar cell development is provided. Photovoltaic equations are described along with instrumentation techniques for measuring solar cells. Radiation effects in solar cells, electrical performance, and spacecraft flight data for solar cells are discussed. The space radiation environment and solar array degradation calculations are addressed.

  1. Backscatter of solar resonance radiation. I.

    NASA Technical Reports Server (NTRS)

    Johnson, H. E.

    1972-01-01

    Calculation of the angular dependence of the intensity of solar Lyman alpha resonantly scattered from neutral interstellar hydrogen which has penetrated the solar system. A simple model which essentially neglects temperature effects, but which includes gravity, radiation pressure, photoionization and charge exchange is used for this calculation. The results are then compared with the observations. The resonant scattering of He I 584 A is also treated.

  2. Stochastic Simulation of Daily Solar Radiation from Sunshine Duration

    NASA Astrophysics Data System (ADS)

    Lockart, N.; Kavetski, D.; Franks, S. W.

    2014-12-01

    Solar radiation is a key component of the energy balance used for estimating evaporation. As solar radiation is not widely measured, many empirical models have been developed to estimate solar radiation using sunshine hours (SSH) data. Most of these models only provide deterministic estimates of monthly solar radiation and do not provide an estimate of the uncertainty in the predictions. This study developed five stochastic models which use daily SSH data to produce probabilistic simulations of solar radiation, and can be used to estimate historical daily radiation. The predictive uncertainty due to the timing of the SSH during the day (estimated using Monte Carlo simulation), as well as due to external errors (such as the variability in cloud type and atmospheric composition), were considered. The developed models differ in their parameterisation of the direct and diffuse components of the solar radiation, using either no scaling, linear or quadratic scaling of the radiation by the daily SSH fraction to account for cloud attenuation. For each model the simulated solar radiation was compared with the observed radiation. The performance of the five models was compared and the models were found to perform similarly well, with an average error of approximately 9% for all locations studied. The results suggest that the uncertainty due to the timing of the SSH does not dominate predictive errors in global radiation. Rather the external uncertainty is the dominant source of predictive error in the radiation estimates.

  3. Radiation Models

    ERIC Educational Resources Information Center

    James, W. G. G.

    1970-01-01

    Discusses the historical development of both the wave and the corpuscular photon model of light. Suggests that students should be informed that the two models are complementary and that each model successfully describes a wide range of radiation phenomena. Cites 19 references which might be of interest to physics teachers and students. (LC)

  4. Mathematical modeling for the forest fuel layer ignition caused by focused solar radiation flux

    NASA Astrophysics Data System (ADS)

    Baranovskiy, Nikolay V.

    2015-11-01

    Forest fuel layer ignition conditions analysis by focused flow of sunlight is lead. Scenarios of simulation corresponds to occurrence of forest fire as result of focused flux of sunlight influence on forest fuel layer. Scenarios calculations taking into account various intensity of radiation are lead. Recommendations on the further development of this component of determined model are submitted.

  5. Spectral distribution of solar radiation on clear days - A comparison between measurements and model estimates

    NASA Astrophysics Data System (ADS)

    Hansen, V.

    1984-05-01

    The distribution of direct and scattered solar radiant energy in the UV (295-385-nm), blue (385-495-nm), green-orange (495-630-nm), red (630-695-nm), and IR (695-2800-nm) bands commonly used in precision spectral pyranometers is estimated for clear sky conditions as a function of solar height, using a plane-parallel atmosphere model and data on the seasonal variation of the UV component at latitude 59.7 deg N. Integrated daily fluxes are also calculated for selected days of the year, and the results are compared with experimental measurements in graphs and tables. The model is found to give reasonable agreement with the observations, but fails to account for a significant blue shift with increasing solar height at heights above 15 deg. The measured distribution for March is given as UV 4.2, blue 8.9, green-orange 21.8, red 12.4, and IR 52.9 percent; for July, the respective values are 4.6, 16.1, 18.0, 10.7, and 50.6 percent.

  6. Solar UV radiation exposure of seamen - Measurements, calibration and model calculations of erythemal irradiance along ship routes

    SciTech Connect

    Feister, Uwe; Meyer, Gabriele; Kirst, Ulrich

    2013-05-10

    Seamen working on vessels that go along tropical and subtropical routes are at risk to receive high doses of solar erythemal radiation. Due to small solar zenith angles and low ozone values, UV index and erythemal dose are much higher than at mid-and high latitudes. UV index values at tropical and subtropical Oceans can exceed UVI = 20, which is more than double of typical mid-latitude UV index values. Daily erythemal dose can exceed the 30-fold of typical midlatitude winter values. Measurements of erythemal exposure of different body parts on seamen have been performed along 4 routes of merchant vessels. The data base has been extended by two years of continuous solar irradiance measurements taken on the mast top of RV METEOR. Radiative transfer model calculations for clear sky along the ship routes have been performed that use satellite-based input for ozone and aerosols to provide maximum erythemal irradiance and dose. The whole data base is intended to be used to derive individual erythemal exposure of seamen during work-time.

  7. Solar UV radiation exposure of seamen - Measurements, calibration and model calculations of erythemal irradiance along ship routes

    NASA Astrophysics Data System (ADS)

    Feister, Uwe; Meyer, Gabriele; Kirst, Ulrich

    2013-05-01

    Seamen working on vessels that go along tropical and subtropical routes are at risk to receive high doses of solar erythemal radiation. Due to small solar zenith angles and low ozone values, UV index and erythemal dose are much higher than at mid-and high latitudes. UV index values at tropical and subtropical Oceans can exceed UVI = 20, which is more than double of typical mid-latitude UV index values. Daily erythemal dose can exceed the 30-fold of typical midlatitude winter values. Measurements of erythemal exposure of different body parts on seamen have been performed along 4 routes of merchant vessels. The data base has been extended by two years of continuous solar irradiance measurements taken on the mast top of RV METEOR. Radiative transfer model calculations for clear sky along the ship routes have been performed that use satellite-based input for ozone and aerosols to provide maximum erythemal irradiance and dose. The whole data base is intended to be used to derive individual erythemal exposure of seamen during work-time.

  8. SOLAR MODELS WITH REVISED ABUNDANCE

    SciTech Connect

    Bi, S. L.; Li, T. D.; Yang, W. M.; Li, L. H.

    2011-04-20

    We present new solar models in which we use the latest low abundances and further include the effects of rotation, magnetic fields, and extra-mixing processes. We assume that the extra-element mixing can be treated as a diffusion process, with the diffusion coefficient depending mainly on the solar internal configuration of rotation and magnetic fields. We find that such models can well reproduce the observed solar rotation profile in the radiative region. Furthermore, the proposed models can match the seismic constraints better than the standard solar models, also when these include the latest abundances, but neglect the effects of rotation and magnetic fields.

  9. Obliquity Modulation of the Incoming Solar Radiation

    NASA Technical Reports Server (NTRS)

    Liu, Han-Shou; Smith, David E. (Technical Monitor)

    2001-01-01

    Based on a basic principle of orbital resonance, we have identified a huge deficit of solar radiation induced by the combined amplitude and frequency modulation of the Earth's obliquity as possibly the causal mechanism for ice age glaciation. Including this modulation effect on solar radiation, we have performed model simulations of climate change for the past 2 million years. Simulation results show that: (1) For the past 1 million years, temperature fluctuation cycles were dominated by a 100-Kyr period due to amplitude-frequency resonance effect of the obliquity; (2) From 2 to 1 million years ago, the amplitude-frequency interactions. of the obliquity were so weak that they were not able to stimulate a resonance effect on solar radiation; (3) Amplitude and frequency modulation analysis on solar radiation provides a series of resonance in the incoming solar radiation which may shift the glaciation cycles from 41-Kyr to 100-Kyr about 0.9 million years ago. These results are in good agreement with the marine and continental paleoclimate records. Thus, the proposed climate response to the combined amplitude and frequency modulation of the Earth's obliquity may be the key to understanding the glaciation puzzles in paleoclimatology.

  10. Simulation of solar radiative transfer in cumulus clouds

    SciTech Connect

    Zuev, V.E.; Titov, G.A.

    1996-04-01

    This work presents a 3-D model of radiative transfer which is used to study the relationship between the spatial distribution of cumulus clouds and fluxes (albedo and transmittance) of visible solar radiation.

  11. Orbiter radiator panel solar focusing test

    NASA Technical Reports Server (NTRS)

    Howell, H. R.

    1982-01-01

    A test was conducted to determine the solar reflections from the Orbiter radiator panels. A one-tenth scale model of the forward and mid-forward radiator panels in the deployed position was utilized in the test. Test data was obtained to define the reflected one-sun envelope for the embossed silver/Teflon radiator coating. The effects of the double contour on the forward radiator panels were included in the test. Solar concentrations of 2 suns were measured and the one-sun envelope was found to extend approximately 86 inches above the radiator panel. A limited amount of test data was also obtained for the radiator panels with the smooth silver/Teflon coating to support the planned EVA on the Orbiter STS-5 flight. Reflected solar flux concentrations as high as 8 suns were observed with the smooth coating and the one-sun envelope was determined to extend 195 inches above the panel. It is recommended that additional testing be conducted to define the reflected solar environment beyond the one-sun boundary.

  12. Solar radiation signature manifested on the spatial patterns of modeled soil moisture, vegetation, and topography using an ecohydro-geomorphic landscape evolution model

    NASA Astrophysics Data System (ADS)

    Yetemen, O.; Flores Cervantes, J. H.; Istanbulluoglu, E.; Vivoni, E. R.

    2013-12-01

    The role of solar radiation on ecohydrologic fluxes, vegetation dynamics, species composition, and landscape morphology have long been documented in field studies. However a numerical model framework to integrate a range of ecohydrologic and geomorphic processes to explore the integrated ecohydro-geomorphic landscape response have been missing. In this study, our aim is to realistically represent flood generation and solar-radiation-driven echydrologic dynamics in a landscape evolution model (LEM) to investigate how ecohydrologic differences caused by differential irradiance on opposing hillslopes manifest themselves on the organization of modeled topography, soil moisture and plant biomass. We use the CHILD LEM equipped with a spatially-distributed solar-radiation component, leading to spatial patterns of soil moisture; a vegetation dynamics component that explicitly tracks above- and below-ground biomass; and a runoff component that allows for runoff-runon processes along the landscape flow paths. Ecohydrological component has been verified using a detailed data gathered from Sevilleta National Wildlife Refuge in central New Mexico, and Walnut Gulch Experimental Watershed in southern Arizona. LEM scenarios were designed to compare the outcomes of spatially distributed versus spatially uniform solar radiation forced with a constant climate and variable uplift. Modeled spatial patterns of soil moisture confirm empirical observations at the landscape scale and other hydrologic modeling studies. The spatial variability in soil moisture is controlled by aspect prior to the wet season (North American Monsoon, NAM), and by the hydraulic connectivity of the flow network during NAM. Aspect and network connectivity signatures are also manifested on plant biomass with typically denser vegetation cover on north-facing slopes than south facing slopes. Over the long-term, CHILD gives slightly steeper and less dissected north-facing slopes more dissected south facing slopes and

  13. Solar Radiation Empirical Quality Assessment

    Energy Science and Technology Software Center (ESTSC)

    1994-03-01

    The SERIQC1 subroutine performs quality assessment of one, two, or three-component solar radiation data (global horizontal, direct normal, and diffuse horizontal) obtained from one-minute to one-hour integrations. Included in the package is the QCFIT tool to derive expected values from historical data, and the SERIQC1 subroutine to assess the quality of measurement data.

  14. Global forecast model to predict the daily dose of the solar erythemally effective UV radiation.

    PubMed

    Schmalwieser, Alois W; Schauberger, Günther; Janouch, Michal; Nunez, Manuel; Koskela, Tapani; Berger, Daniel; Karamanian, Gabriel

    2005-01-01

    A worldwide forecast of the erythemally effective ultraviolet (UV) radiation is presented. The forecast was established to inform the public about the expected amount of erythemally effective UV radiation for the next day. Besides the irradiance, the daily dose is forecasted to enable people to choose the appropriate sun protection tools. Following the UV Index as the measure of global erythemally effective irradiance, the daily dose is expressed in units of UV Index hours. In this study, we have validated the model and the forecast against measurements from broadband UV radiometers of the Robertson-Berger type. The measurements were made at four continents ranging from the northern polar circle (67.4 degrees N) to the Antarctic coast (61.1 degrees S). As additional quality criteria the frequency of underestimation was taken into account because the forecast is a tool of radiation protection and made to avoid overexposure. A value closer than one minimal erythemal dose for the most sensitive skin type 1 to the observed value was counted as hit and greater deviations as underestimation or overestimation. The Austrian forecast model underestimates the daily dose in 3.7% of all cases, whereas 1.7% results from the model and 2.0% from the assumed total ozone content. The hit rate could be found in the order of 40%. PMID:15453822

  15. Side-effects of a bad attitude: How GNSS spacecraft orientation errors affect solar radiation pressure modelling

    NASA Astrophysics Data System (ADS)

    Dilssner, Florian; Springer, Tim; Schönemann, Erik; Zandbergen, Rene; Enderle, Werner

    2015-04-01

    Solar radiation pressure (SRP) is the largest non-gravitational perturbation for Global Navigation Satellite System (GNSS) satellites, and can therefore have substantial impact on their orbital dynamics. Various SRP force models have been developed over the past 30 years for the purpose of precise orbit determination. They all rely upon the assumption that the satellites continuously maintain a Sun-Nadir pointing attitude with the navigation antenna boresight (body-fixed z-axis) pointing towards Earth center, and the solar panel rotation axis (body-fixed y-axis) being normal to the Sun direction. However, in reality, this is not perfectly the case. Reasons for a non-nominal spacecraft attitude may be eclipse maneuvers, commanded attitude biases and Sun/horizon sensor measurement errors, for example due to mounting misalignment or incorrectly calibrated sensor electronics. In this work the effect of GNSS spacecraft orientation errors on SRP modelling is investigated. Simplified mathematical functions describing the SRP force acting on the solar arrays in the presence of yaw-, pitch- and roll-biases are derived. Special attention is paid to the yaw-bias and its relationship to the SRP dynamics, particular in direction of the spacecraft y-axis ("y-bias force"). Analytical and experimental results gathered from orbit and attitude analyses of GPS Block II/IIA/IIF satellites demonstrate how sensitive the SRP coefficients are to changes in yaw.

  16. SORCE: Solar Radiation and Climate Experiment

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert; Rottman, Gary; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Contents include the following: Understanding the Sun's influence on the Earth; How the Sun affect Earth's climate; By how much does the Sun's radiation very; Understanding Solar irradiance; History of Solar irradiance observations; The SORCE mission; How do the SORCE instruments measure solar radiation; Total irradiance monitor (TIM); Spectral irradiance monitor (SIM); Solar stellar irradiance comparison experiment (SOLSTICE); XUV photometer system (XPS).

  17. Use of Displacement Damage Dose in an Engineering Model of GaAs Solar Cell Radiation Damage

    NASA Technical Reports Server (NTRS)

    Morton, T. L.; Chock, R.; Long, K. J.; Bailey, S.; Messenger, S. R.; Walters, R. J.; Summers, G. P.

    2005-01-01

    Current methods for calculating damage to solar cells are well documented in the GaAs Solar Cell Radiation Handbook (JPL 96-9). An alternative, the displacement damage dose (D(sub d)) method, has been developed by Summers, et al. This method is currently being implemented in the SAVANT computer program.

  18. Projections of long-term changes in solar radiation based on CMIP5 climate models and their influence on energy yields of photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Wild, Martin; Folini, Doris; Henschel, Florian; Müller, Björn

    2015-04-01

    Traditionally, for the planning and assessment of solar energy systems, the amount of solar radiation (sunlight) incident on the Earth's surface is assumed to be constant over the years. However, with changing climate and air pollution levels, solar resources may no longer be stable over time and undergo substantial decadal changes. Observational records covering the past decades confirm long-term changes in this quantity. Here we examine, how the latest generation of climate models used for the 5th IPCC report projects potential changes in surface solar radiation over the coming decades, and how this may affect, in combination with the expected greenhouse warming, solar power output from photovoltaic (PV) systems. For this purpose, projections up to the mid 21th century from 39 state of the art climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) are analysed globally and for selected key regions with major solar power production capacity. The large model ensemble allows to assess the degree of consistency of their projections. Models are largely consistent in the sign of the projected changes in solar radiation under cloud-free conditions as well as in surface temperatures over most of the globe, while still reasonably consistent over a considerable part of the globe in the sign of changes in cloudiness and associated changes in solar radiation. A first order estimate of the impact of solar radiation and temperature changes on energy yields of PV systems under the RPC8.5 scenario indicates statistically significant decreases in PV outputs in large parts of the world, but notable exceptions with positive trends in parts of Europe and the South-East of China. Projected changes between 2006 and 2049 under the RCP8.5 scenario overall are on the order of 1 % per decade for horizontal planes, but may be larger for tilted or tracked planes as well as on shorter (decadal) timescales. Related References: Wild, M., Folini, D., Henschel, F., and M

  19. Wetlands Evapotranspiration Using Remotely Sensed Solar Radiation

    NASA Astrophysics Data System (ADS)

    Jacobs, J. M.; Myers, D. A.; Anderson, M. C.

    2001-12-01

    The application of remote sensing methods to estimate evapotranspiration has the advantage of good spatial resolution and excellent spatial coverage, but may have the disadvantage of infrequent sampling and considerable expense. The GOES satellites provide enhanced temporal resolution with hourly estimates of solar radiation and have a spatial resolution that is significantly better than that available from most ground-based pyranometer networks. As solar radiation is the primary forcing variable in wetland evapotranspiration, the opportunity to apply GOES satellite data to wetland hydrologic analyses is great. An accuracy assessment of the remote sensing product is important and the subsequent validation of the evapotranspiration estimates are a critical step for the use of this product. A wetland field experiment was conducted in the Paynes Prairie Preserve, North Central Florida during a growing season characterized by significant convective activity. Evapotranspiration and other surface energy balance components of a wet prairie community dominated by Panicum hemitomon (maiden cane), Ptilimnium capillaceum (mock bishop's weed), and Eupatorium capillifolium (dog fennel) were investigated. Incoming solar radiation derived from GOES-8 satellite observations, in combination with local meteorological measurements, were used to model evapotranspiration from a wetland. The satellite solar radiation, derived net radiation and estimated evapotranspiration estimates were compared to measured data at 30-min intervals and daily times scales.

  20. Solar Radiation: An Anomalous Decrease of Direct Solar Radiation.

    PubMed

    Flowers, E C; Viebrock, H J

    1965-04-23

    Beginning in November 1963, measurements made at the South Pole of solar radiation at normal incidence indicate a decrease of from 5 to 78 percent of the normal intensity. Similar measurements made at Mauna Loa, Hawaii, show a similar though smaller reduction. The causal factor is believed to be a layer of atmospheric dust resulting from the eruption of Mt. Agung, Bali, in March 1963. PMID:17842839

  1. Accessing Topographic Effects on Solar Radiation Distribution and Ecohydrological Processes

    NASA Astrophysics Data System (ADS)

    Fang, Y.; Niu, G. Y.; Troch, P. A. A.; Paniconi, C.; Durcik, M.; Chorover, J.

    2014-12-01

    Solar radiation is the driving force for terrestrial ecohydrological processes. In mountainous regions, solar radiation reaching the land surface is strongly affected by topographic conditions (e.g., terrain slope and aspect) resulting in unevenly distributed solar radiation. This further affects ecohydrological processes including evapotranspiration, snowmelt, and runoff. However, most distributed hydrological models directly use measured or directly interpolated (e.g. IDW) solar radiation as inputs, not accounting for the topographic effects on solar radiation distribution. In this study, we first implemented a solar radiation spatial interpolation scheme to a fully integrated catchment-scale ecohydrological model by taking into account the topographic effects on direct (shading), diffuse (scattering) and reflected solar radiation. The resulting spatial distribution is more realistic than the direct interpolation. We applied the scheme to Marshall Gulch in Arizona, a mountainous catchment at different spatial resolutions. We will present some modeling results to show the topographic effects on solar radiation distribution, snow mass, vegetation growth, and runoff production, as well as the model sensitivity to modeling resolutions.

  2. Modeling solar magnetic structures

    NASA Technical Reports Server (NTRS)

    Low, B. C.

    1985-01-01

    Some ideas in the theoretical study of force-free magnetic fields and magnetostatic fields, which are relevant to the effort of using magnetograph data as inputs to model the quasi-static, large-scale magnetic structures in the solar atmosphere are discussed. Basic physical principles will be emphasized. An attempt will be made to assess what we may learn, physically, from the models based on these ideas. There is prospect for learning useful physics and this ought to be an incentive for intensifying the efforts to improve vector magnetograph technology and to solve the basic radiative-transfer problems encountered in the interpretation of magnetograph raw data.

  3. Photocatalytic mineralization of commercial herbicides in a pilot-scale solar CPC reactor: photoreactor modeling and reaction kinetics constants independent of radiation field.

    PubMed

    Colina-Márquez, Jose; Machuca-Martínez, Fiderman; Li Puma, Gianluca

    2009-12-01

    The six-flux absorption-scattering model (SFM) of the radiation field in the photoreactor, combined with reaction kinetics and fluid-dynamic models, has proved to be suitable to describe the degradation of water pollutants in heterogeneous photocatalytic reactors, combining simplicity and accuracy. In this study, the above approach was extended to model the photocatalytic mineralization of a commercial herbicides mixture (2,4-D, diuron, and ametryne used in Colombian sugar cane crops) in a solar, pilot-scale, compound parabolic collector (CPC) photoreactor using a slurry suspension of TiO(2). The ray-tracing technique was used jointly with the SFM to determine the direction of both the direct and diffuse solar photon fluxes and the spatial profile of the local volumetric rate of photon absorption (LVRPA) in the CPC reactor. Herbicides mineralization kinetics with explicit photon absorption effects were utilized to remove the dependence of the observed rate constants from the reactor geometry and radiation field in the photoreactor. The results showed that the overall model fitted the experimental data of herbicides mineralization in the solar CPC reactor satisfactorily for both cloudy and sunny days. Using the above approach kinetic parameters independent of the radiation field in the reactor can be estimated directly from the results of experiments carried out in a solar CPC reactor. The SFM combined with reaction kinetics and fluid-dynamic models proved to be a simple, but reliable model, for solar photocatalytic applications. PMID:19943672

  4. Estimation of global solar radiation in Nigeria using a modified Angstrom model and the trend analysis of the allied meteorological components

    NASA Astrophysics Data System (ADS)

    Ogolo, E. O.

    2014-06-01

    The trend of some common and related atmospheric variables were investigated in the light of climate change on annual time scale and a suitable scheme was further developed for the simulation of annual global solar radiation in Nigeria. In this connection, annual trends of global solar radiation, air temperature, precipitation, relative humidity and sunshine hours was carried out, covering about 13 tropical stations during 1975-2006 in Nigeria using F-test as the significance test technique. It was found that nine stations exhibited an upward trend in global solar radiation series, of which 6 passed F-test at 1% significant level. At 11 stations, precipitation had shown an increasing trends but none passed F-test at 2.5% and hence, not significant. About 98.8% of the stations displayed an upward trend in sunshine hours of which 16% passed F-test at 1% significant level. On trend analysis for relative humidity series, eight stations exhibited a positive trend and only one station passed F-test at 1% significant level. The trend of temperature series in Nigeria under the period under investigation was found to be increasing at 12 stations and eight stations passed the F-test at 1% significant level. The other objective of this study was to determine a more suitable empirical equation by modifying Angstrom model for the estimation of global solar radiation using all data for all 14 stations pooled together to predict global solar radiation using linear and multiple linear regression. This was done to improve the low performance of the Angstrom model used for the annual estimation of global solar radiation. The model parameters 'a' and 'b' of Angstrom model were parameterized in terms of the geographical locations (latitude, longitude and elevation) and the meteorological variables (sunshine hour, precipitation, relative humidity and temperature), respectively. This scheme gave better simulation of the global solar radiation compared wi! th other schemes and the

  5. Data-driven Radiative Hydrodynamic Modeling of the 2014 March 29 X1.0 Solar Flare

    NASA Astrophysics Data System (ADS)

    Rubio da Costa, Fatima; Kleint, Lucia; Petrosian, Vahé; Liu, Wei; Allred, Joel C.

    2016-08-01

    Spectroscopic observations of solar flares provide critical diagnostics of the physical conditions in the flaring atmosphere. Some key features in observed spectra have not yet been accounted for in existing flare models. Here we report a data-driven simulation of the well-observed X1.0 flare on 2014 March 29 that can reconcile some well-known spectral discrepancies. We analyzed spectra of the flaring region from the Interface Region Imaging Spectrograph (IRIS) in Mg ii h&k, the Interferometric BIdimensional Spectropolarimeter at the Dunn Solar Telescope (DST/IBIS) in Hα 6563 Å and Ca ii 8542 Å, and the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) in hard X-rays. We constructed a multithreaded flare loop model and used the electron flux inferred from RHESSI data as the input to the radiative hydrodynamic code RADYN to simulate the atmospheric response. We then synthesized various chromospheric emission lines and compared them with the IRIS and IBIS observations. In general, the synthetic intensities agree with the observed ones, especially near the northern footpoint of the flare. The simulated Mg ii line profile has narrower wings than the observed one. This discrepancy can be reduced by using a higher microturbulent velocity (27 km s‑1) in a narrow chromospheric layer. In addition, we found that an increase of electron density in the upper chromosphere within a narrow height range of ≈800 km below the transition region can turn the simulated Mg ii line core into emission and thus reproduce the single peaked profile, which is a common feature in all IRIS flares.

  6. A behavioral model for estimating population exposure to solar ultraviolet radiation.

    PubMed

    Diffey, Brian

    2008-01-01

    Determining the variability of solar UV exposure of different members of a population by direct measurement demands high compliance over an extended period of time by a large number of people. An alternative approach is to model the variables that affect personal exposure and this is the basis of the method reported here, which uses a random sampling technique to explore variability of exposure at different times of the year by habitués. It is shown that there are large variations in daily personal erythemal exposure, more so for indoor workers living in northern Europe than those resident in Florida, which are due not only to seasonal changes in ambient, but just as importantly to seasonal variation in behavior. Not surprisingly, holiday and summer weekend exposure account for the largest daily UV doses. Northern Europeans who take their summer vacation in Florida can double their exposure during this period compared with holidaying at home and this illustrates just how important sun protection measures should be during recreational exposure in areas of high insolation if the annual UV burden is to be sensibly controlled. PMID:18208455

  7. Modeling of growth and evaporation effects on the extinction of 1.0-micron solar radiation traversing stratospheric sulfuric acid aerosols

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Deepak, A.

    1981-01-01

    The effects of growth and evaporation of stratospheric sulfuric acid aerosols on the extinction of solar radiation traversing such an aerosol medium are reported for the case of 1.0-micron solar radiation. Modeling results show that aerosol extinction is not very sensitive to the change of ambient water vapor concentration, but is sensitive to ambient temperature changes, especially at low ambient temperatures and high ambient water vapor concentration. A clarification is given of the effects of initial aerosol size distribution and composition on the change of aerosol extinction due to growth and evaporation processes. It is shown that experiments designed to observe solar radiation extinction of aerosols may also be applied to the determination of observed changes in aerosol optical properties, environmental parameters, or the physical and optical characteristics of sulfate aerosols.

  8. A general model for estimation of daily global solar radiation using air temperatures and site geographic parameters in Southwest China

    NASA Astrophysics Data System (ADS)

    Li, Mao-Fen; Fan, Li; Liu, Hong-Bin; Guo, Peng-Tao; Wu, Wei

    2013-01-01

    Estimation of daily global solar radiation (Rs) from routinely measured temperature data has been widely developed and used in many different areas of the world. However, many of them are site specific. It is assumed that a general model for estimating daily Rs using temperature variables and geographical parameters could be achieved within a climatic region. This paper made an attempt to develop a general model to estimate daily Rs using routinely measured temperature data (maximum (Tmax, °C) and minimum (Tmin, °C) temperatures) and site geographical parameters (latitude (La, °N), longitude (Ld, °E) and altitude (Alt, m)) for Guizhou and Sichuan basin of southwest China, which was classified into the hot summer and cold winter climate zone. Comparison analysis was carried out through statistics indicators such as root mean squared error of percentage (RMSE%), modeling efficiency (ME), coefficient of residual mass (CRM) and mean bias error (MBE). Site-dependent daily Rs estimating models were calibrated and validated using long-term observed weather data. A general formula was then obtained from site geographical parameters and the better fit site-dependent models with mean RMSE% of 38.68%, mean MBE of 0.381 MJ m-2 d-1, mean CRM of 0.04 and mean ME value of 0.713.

  9. Variation of solar cell sensitivity and solar radiation on tilted surfaces

    NASA Technical Reports Server (NTRS)

    Klucher, T. M.

    1978-01-01

    The validity is studied that one of various insolation models used to compute solar radiation incident on tilted surfaces from global data measured on horizontal surfaces. The variation of solar cell sensitivity to solar radiation is determined over a wide range of atmospheric condition. A new model was formulated that reduced the deviations between measured and predicted insolation to less than 3 percent. Evaluation of solar cell sensitivity data indicates small change (2-3 percent) in sensitivity from winter to summer for tilted cells. The feasibility of using such global data as a means for calibrating terrestrial solar cells is discussed.

  10. Orbit determination modelling analysis using GPS including perturbations due to geopotential coefficients of high degree and order, solar radiation pressure and luni-solar attraction

    NASA Astrophysics Data System (ADS)

    Vilhena de Moraes, Rodolpho; Cristiane Pardal, Paula; Koiti Kuga, Helio

    The problem of orbit determination consists essentially of estimating parameter values that completely specify the body trajectory in the space, processing a set of information (measure-ments) from this body. Such observations can be collected through a conventional tracking network on Earth or through sensors like GPS. The Global Positioning System (GPS) is a powerful and low cost way to allow the computation of orbits for artificial Earth satellites. The Topex/Poseidon satellite is normally used as a reference for analyzing this system for space positioning. The orbit determination of artificial satellites is a nonlinear problem in which the disturbing forces are not easily modeled, like geopotential and direct solar radiation pressure. Through an onboard GPS receiver it is possible to obtain measurements (pseudo-range and phase) that can be used to estimate the state of the orbit. One intends to analyze the modeling of the orbit of an artificial satellite, using signals of the GPS constellation and least squares algorithms as a method of estimation, with the aim of analyzing the performance of the orbit estimation process. Accuracy is not the main goal; one pursues to verify how differences of modeling can affect the final accuracy of the orbit determination. To accomplish that, the following effects were considered: perturbations up to high degree and order for the geopoten-tial coefficients; direct solar radiation pressure, Sun attraction, and Moon attraction. It was also considered the position of the GPS antenna on the satellite body that, lately, consists of the influence of the satellite attitude motion in the orbit determination process. Although not presenting the ultimate accuracy, pseudo-range measurements corrected from ionospheric effects were considered enough to such analysis. The measurements were used to feed the batch least squares orbit determination process, in order to yield conclusive results about the orbit modeling issue. An application

  11. GaAs Solar Cell Radiation Handbook

    NASA Technical Reports Server (NTRS)

    Anspaugh, B. E.

    1996-01-01

    The handbook discusses the history of GaAs solar cell development, presents equations useful for working with GaAs solar cells, describes commonly used instrumentation techniques for assessing radiation effects in solar cells and fundamental processes occurring in solar cells exposed to ionizing radiation, and explains why radiation decreases the electrical performance of solar cells. Three basic elements required to perform solar array degradation calculations: degradation data for GaAs solar cells after irradiation with 1 MeV electrons at normal incidence; relative damage coefficients for omnidirectional electron and proton exposure; and the definition of the space radiation environment for the orbit of interest, are developed and used to perform a solar array degradation calculation.

  12. Temporal variability patterns in solar radiation estimations

    NASA Astrophysics Data System (ADS)

    Vindel, José M.; Navarro, Ana A.; Valenzuela, Rita X.; Zarzalejo, Luis F.

    2016-06-01

    In this work, solar radiation estimations obtained from a satellite and a numerical weather prediction model in mainland Spain have been compared. Similar comparisons have been formerly carried out, but in this case, the methodology used is different: the temporal variability of both sources of estimation has been compared with the annual evolution of the radiation associated to the different study climate zones. The methodology is based on obtaining behavior patterns, using a Principal Component Analysis, following the annual evolution of solar radiation estimations. Indeed, the adjustment degree to these patterns in each point (assessed from maps of correlation) may be associated with the annual radiation variation (assessed from the interquartile range), which is associated, in turn, to different climate zones. In addition, the goodness of each estimation source has been assessed comparing it with data obtained from the radiation measurements in ground by pyranometers. For the study, radiation data from Satellite Application Facilities and data corresponding to the reanalysis carried out by the European Centre for Medium-Range Weather Forecasts have been used.

  13. Absorption of solar radiation in broken clouds

    SciTech Connect

    Zuev, V.E.; Titov, G.A.; Zhuravleva, T.B.

    1996-04-01

    It is recognized now that the plane-parallel model unsatisfactorily describes the transfer of radiation through broken clouds and that, consequently, the radiation codes of general circulation models (GCMs) must be refined. However, before any refinement in a GCM code is made, it is necessary to investigate the dependence of radiative characteristics on the effects caused by the random geometry of cloud fields. Such studies for mean fluxes of downwelling and upwelling solar radiation in the visible and near-infrared (IR) spectral range were performed by Zuev et al. In this work, we investigate the mean spectral and integrated absorption of solar radiation by broken clouds (in what follows, the term {open_quotes}mean{close_quotes} will be implied but not used, for convenience). To evaluate the potential effect of stochastic geometry, we will compare the absorption by cumulus (0.5 {le} {gamma} {le} 2) to that by equivalent stratus ({gamma} <<1) clouds; here {gamma} = H/D, H is the cloud layer thickness and D the characteristic horizontal cloud size. The equivalent stratus clouds differ from cumulus only in the aspect ratio {gamma}, all the other parameters coinciding.

  14. Modelling the performance of the tapered artery heat pipe design for use in the radiator of the solar dynamic power system of the NASA Space Station

    NASA Technical Reports Server (NTRS)

    Evans, Austin Lewis

    1988-01-01

    The paper presents a computer program developed to model the steady-state performance of the tapered artery heat pipe for use in the radiator of the solar dynamic power system of the NASA Space Station. The program solves six governing equations to ascertain which one is limiting the maximum heat transfer rate of the heat pipe. The present model appeared to be slightly better than the LTV model in matching the 1-g data for the standard 15-ft test heat pipe.

  15. Effect of Estimated Daily Global Solar Radiation Data on the Results of Crop Growth Models

    PubMed Central

    Trnka, Miroslav; Eitzinger, Josef; Kapler, Pavel; Dubrovský, Martin; Semerádová, Daniela; Žalud, Zden ěk; Formayer, Herbert

    2007-01-01

    The results of previous studies have suggested that estimated daily global radiation (RG) values contain an error that could compromise the precision of subsequent crop model applications. The following study presents a detailed site and spatial analysis of the RG error propagation in CERES and WOFOST crop growth models in Central European climate conditions. The research was conducted i) at the eight individual sites in Austria and the Czech Republic where measured daily RG values were available as a reference, with seven methods for RG estimation being tested, and ii) for the agricultural areas of the Czech Republic using daily data from 52 weather stations, with five RG estimation methods. In the latter case the RG values estimated from the hours of sunshine using the Ångström-Prescott formula were used as the standard method because of the lack of measured RG data. At the site level we found that even the use of methods based on hours of sunshine, which showed the lowest bias in RG estimates, led to a significant distortion of the key crop model outputs. When the Ångström-Prescott method was used to estimate RG, for example, deviations greater than ±10 per cent in winter wheat and spring barley yields were noted in 5 to 6 per cent of cases. The precision of the yield estimates and other crop model outputs was lower when RG estimates based on the diurnal temperature range and cloud cover were used (mean bias error 2.0 to 4.1 per cent). The methods for estimating RG from the diurnal temperature range produced a wheat yield bias of more than 25 per cent in 12 to 16 per cent of the seasons. Such uncertainty in the crop model outputs makes the reliability of any seasonal yield forecasts or climate change impact assessments questionable if they are based on this type of data. The spatial assessment of the RG data uncertainty propagation over the winter wheat yields also revealed significant differences within the study area. We found that RG estimates based on

  16. Solar radiation and human health

    NASA Astrophysics Data System (ADS)

    Juzeniene, Asta; Brekke, Pål; Dahlback, Arne; Andersson-Engels, Stefan; Reichrath, Jörg; Moan, Kristin; Holick, Michael F.; Grant, William B.; Moan, Johan

    2011-06-01

    The Sun has played a major role in the development of life on Earth. In Western culture, people are warned against Sun exposure because of its adverse effects: erythema, photoimmunosuppression, photoageing, photocarcinogenesis, cataracts and photokeratitis. However, Sun exposure is also beneficial, since moderate doses give beneficial physiological effects: vitamin D synthesis, reduction of blood pressure and mental health. Shortage of Sun exposure may be even more dangerous to human health than excessive exposure. Avoiding Sun exposure leads to vitamin D deficiency which is associated not only with rickets and osteomalacia, but also with increased risk of cardiovascular disease, multiple sclerosis, rheumatoid arthritis, diabetes, influenza, many types of cancer and adverse pregnancy outcomes. Solar radiation induces nitric oxide release in tissue and immediate pigment darkening which certainly play important roles, although these are still unknown. Action spectra relevant for health are described. We will also review what is known about spectral and intensity variations of terrestrial solar radiation as well as its penetration through the atmosphere and into human skin and tissue.

  17. Relative biological effectiveness of simulated solar particle event proton radiation to induce acute hematological change in the porcine model

    PubMed Central

    Sanzari, Jenine K.; Wan, Steven X.; Diffenderfer, Eric S.; Cengel, Keith A.; Kennedy, Ann R.

    2014-01-01

    The present study was undertaken to determine relative biological effectiveness (RBE) values for simulated solar particle event (SPE) radiation on peripheral blood cells using Yucatan minipigs and electron-simulated SPE as the reference radiation. The results demonstrated a generally downward trend in the RBE values with increasing doses of simulated SPE radiation for leukocytes in the irradiated animals. The fitted RBE values for white blood cells (WBCs), lymphocytes, neutrophils, monocytes and eosinophils were above 1.0 in all three radiation dose groups at all time-points evaluated, and the lower limits of the 95% confidence intervals were > 1.0 in the majority of the dose groups at different time-points, which together suggest that proton-simulated SPE radiation is more effective than electron-simulated SPE radiation in reducing the number of peripheral WBCs, lymphocytes, neutrophils, monocytes and eosinophils, especially at the low end of the 5–10 Gy dose range evaluated. Other than the RBE values, the responses of leukocytes to electron-simulated SPE radiation and proton-simulated SPE radiation exposure are highly similar with respect to the time-course, the most radiosensitive cell type (the lymphocytes), and the shape of the dose–response curves, which is generally log-linear. These findings provide additional evidence that electron-simulated SPE radiation is an appropriate reference radiation for determination of RBE values for the simulated SPE radiations, and the RBE estimations using electron-simulated SPE radiation as the reference radiation are not complicated by other characteristics of the leukocyte response to radiation exposure. PMID:24027300

  18. Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares. II. Inclusion of Radiative Transfer with RADYN

    NASA Astrophysics Data System (ADS)

    Rubio da Costa, Fatima; Liu, Wei; Petrosian, Vahé; Carlsson, Mats

    2015-11-01

    Solar flares involve complex processes that are coupled and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present results from simulations that couple particle kinetics with hydrodynamics (HD) of the atmospheric plasma. We combine the Stanford unified Fokker-Planck code that models particle acceleration and transport with the RADYN HD code that models the atmospheric response to collisional heating by accelerated electrons through detailed radiative transfer calculations. We perform simulations using two different electron spectra, one an ad hoc power law and the other predicted by the model of stochastic acceleration by turbulence or plasma waves. Surprisingly, the later model, even with energy flux \\ll {10}10 {erg} {{{s}}}-1 {{cm}}-2, can cause “explosive” chromospheric evaporation and drive stronger up- and downflows (and HD shocks). This is partly because our acceleration model, like many others, produces a spectrum consisting of a quasi-thermal component plus a power-law tail. We synthesize emission-line profiles covering different heights in the lower atmosphere, including Hα 6563 Å, He ii 304 Å, Ca ii K 3934 Å, and Si iv 1393 Å. One interesting result is the unusual high temperature (up to a few times 105 K) of the formation site of He ii 304 Å, which is expected owing to photoionization-recombination under flare conditions, compared to those in the quiet Sun dominated by collisional excitation. When compared with observations, our results can constrain the properties of nonthermal electrons and thus the poorly understood particle acceleration mechanism.

  19. The measurement of solar ultraviolet radiation.

    PubMed

    Roy, C R; Gies, H P; Lugg, D J; Toomey, S; Tomlinson, D W

    1998-11-01

    High skin cancer rates, stratospheric ozone depletion and increased public interest and concern have resulted in a strong demand for solar ultraviolet radiation measurements and information. The Australian Radiation Laboratory (ARL) has been involved since the mid-1980s in the measurement of solar ultraviolet radiation (UVR) using spectroradiometers (SRM) and a network of broadband detectors at 18 sites in Australia and Antarctica and in Singapore through a collaborative agreement with the Singapore Institute of Science and Forensic Medicine. Measurement locations range from equatorial (Singapore, 1.3 degrees N) through tropical (Darwin, 12.4 degrees S) to polar (Mawson, 67.6 degrees S) and as a result there are many difficulties associated with maintenance and calibration of the network detectors, and transfer of data to ensure an accurate and reliable data collection. Calibration procedures for the various detectors involve the comparison with simultaneous spectral measurements using a portable SRM incorporating a double monochromator, calibrated against traceable standard lamps. Laboratory measurements of cosine response and responsivity are also made. Detectors are intercompared at the Yallambie site for a number of months before installation at another location. As an additional check on the calibrations, computer models of solar UVR at the earth's surface for days with clear sky and known ozone are compared with the UV radiometer measurements. PMID:9920423

  20. NREL Solar Radiation Resource Assessment Project: Status and outlook

    SciTech Connect

    Renne, D.; Riordan, C.; Maxwell, E.; Stoffel, T.; Marion, B.; Rymes, M.; Wilcox, S.; Myers, D.

    1992-05-01

    This report summarizes the activities and accomplishments of NREL's Solar Radiation Resource Assessment Project during fiscal year 1991. Currently, the primary focus of the SRRAP is to produce a 1961--1990 National Solar Radiation Data Base, providing hourly values of global horizontal, diffuse, and direct normal solar radiation at approximately 250 sites around the United States. Because these solar radiation quantities have been measured intermittently at only about 50 of these sites, models were developed and applied to the majority of the stations to provide estimates of these parameters. Although approximately 93% of the data base consists of modeled data this represents a significant improvement over the SOLMET/ERSATZ 1952--1975 data base. The magnitude and importance of this activity are such that the majority of SRRAP human and financial in many other activities, which are reported here. These include the continued maintenance of a solar radiation monitoring network in the southeast United States at six Historically Black Colleges and Universities (HBCU's), the transfer of solar radiation resource assessment technology through a variety of activities, participation in international programs, and the maintenance and operation of NREL's Solar Radiation Research Laboratory. 17 refs.

  1. NREL Solar Radiation Resource Assessment Project: Status and outlook

    NASA Astrophysics Data System (ADS)

    Renne, D.; Riordan, C.; Maxwell, E.; Stoffel, T.; Marion, B.; Rymes, M.; Wilcox, S.; Myers, D.

    1992-05-01

    This report summarizes the activities and accomplishments of NREL's Solar Radiation Resource Assessment Project during fiscal year 1991. Currently, the primary focus of the SRRAP is to produce a 1961 - 1990 National Solar Radiation Data Base, providing hourly values of global horizontal, diffuse, and direct normal solar radiation at approximately 250 sites around the United States. Because these solar radiation quantities were measured intermittently at only about 50 of these sites, models were developed and applied to the majority of the stations to provide estimates of these parameters. Although approximately 93 percent of the data base consists of modeled data this represents a significant improvement over the SOLMET/ERSATZ 1952 - 1975 data base. The magnitude and importance of this activity are such that the majority of SRRAP human and financial resources were devoted to the data base development. However, in FY 1991 the SRRAP was involved in many other activities, which are reported here. These include the continued maintenance of a solar radiation monitoring network in the southeast United States at six Historically Black Colleges and Universities (HBCU's), the transfer of solar radiation resource assessment technology through a variety of activities, participation in international programs, and the maintenance and operation of NREL's Solar Radiation Research Laboratory.

  2. Spectral solar radiation data base documentation

    SciTech Connect

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

    1990-01-01

    The Solar Energy Research Institute (SERI), Electric Power Research Institute, Florida Solar Energy Center, and Pacific Gas and Electric Company cooperated to produce a spectral solar radiation data base representing a range of atmospheric conditions. These data will help to characterize the neutral variability in the spectral (color) content to outdoor solar radiation so that the sensitivity of spectrally selective solar devices (such as photovoltaics) to these variations can be studied quantitatively. Volume 1 of this report documents the history, approach, content, and format of the data base; Volume 2 contains graphs and field notes for each of the spectral data sets. The data reside on magnetic tape at SERI.

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

    SciTech Connect

    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.

  4. Solar radiation on Mars: Stationary photovoltaic array

    NASA Technical Reports Server (NTRS)

    Appelbaum, J.; Sherman, I.; Landis, G. A.

    1993-01-01

    Solar energy is likely to be an important power source for surface-based operation on Mars. Photovoltaic cells offer many advantages. In this article we have presented analytical expressions and solar radiation data for stationary flat surfaces (horizontal and inclined) as a function of latitude, season and atmospheric dust load (optical depth). The diffuse component of the solar radiation on Mars can be significant, thus greatly affecting the optimal inclination angle of the photovoltaic surface.

  5. A new solar radiation data manual for flat-plate and concentrating collectors

    NASA Astrophysics Data System (ADS)

    Marion, W.; Wilcox, S.

    1994-06-01

    A new solar radiation data manual is nearing completion by the National Renewable Energy Laboratory's (NREL's) Analytic Studies Division under the Solar Radiation Resource Assessment Project and the Photovoltaic Solar Radiation Research Task. These tasks are funded and monitored by the Photovoltaics Branch of the Department of Energy's Office of Energy Efficiency and Renewable Energy. The new manual is entitled Solar Radiation Data Manual for Flat-Plate and Concentrating Collectors. For designers and engineers of solar energy related systems, it gives the solar resource available for various types of collectors for 239 stations in the United States and its territories. The data in the manual are modeled using diffuse horizontal and direct beam solar radiation values from the National Solar Radiation Data Base (NSRDB). The NSRDB contains modeled (93%) and measured (7%) global horizontal, diffuse horizontal, and direct beam solar radiation for 1961-1990. This paper describes what is contained in the new data manual and how it was developed.

  6. The potential of different artificial neural network (ANN) techniques in daily global solar radiation modeling based on meteorological data

    SciTech Connect

    Behrang, M.A.; Assareh, E.; Ghanbarzadeh, A.; Noghrehabadi, A.R.

    2010-08-15

    The main objective of present study is to predict daily global solar radiation (GSR) on a horizontal surface, based on meteorological variables, using different artificial neural network (ANN) techniques. Daily mean air temperature, relative humidity, sunshine hours, evaporation, and wind speed values between 2002 and 2006 for Dezful city in Iran (32 16'N, 48 25'E), are used in this study. In order to consider the effect of each meteorological variable on daily GSR prediction, six following combinations of input variables are considered: (I)Day of the year, daily mean air temperature and relative humidity as inputs and daily GSR as output. (II)Day of the year, daily mean air temperature and sunshine hours as inputs and daily GSR as output. (III)Day of the year, daily mean air temperature, relative humidity and sunshine hours as inputs and daily GSR as output. (IV)Day of the year, daily mean air temperature, relative humidity, sunshine hours and evaporation as inputs and daily GSR as output. (V)Day of the year, daily mean air temperature, relative humidity, sunshine hours and wind speed as inputs and daily GSR as output. (VI)Day of the year, daily mean air temperature, relative humidity, sunshine hours, evaporation and wind speed as inputs and daily GSR as output. Multi-layer perceptron (MLP) and radial basis function (RBF) neural networks are applied for daily GSR modeling based on six proposed combinations. The measured data between 2002 and 2005 are used to train the neural networks while the data for 214 days from 2006 are used as testing data. The comparison of obtained results from ANNs and different conventional GSR prediction (CGSRP) models shows very good improvements (i.e. the predicted values of best ANN model (MLP-V) has a mean absolute percentage error (MAPE) about 5.21% versus 10.02% for best CGSRP model (CGSRP 5)). (author)

  7. Progress Toward an Updated National Solar Radiation Data Base

    SciTech Connect

    Wilcox, S.; Anderberg, M.; George, R.; Marion, W.; Myers, D.; Renne, D.; Beckman, W.; DeGaetano, A.; Gueymard, C.; Perez, R.; Plantico, M.; Stackhouse, P.; Vignola, F.

    2005-01-01

    Progress is reported on an updated National Solar Radiation Database (NSRDB). Focus on this year's work was on preparing a test-year database for evaluating several solar radiation models that could be used to replace the METSTAT model used in the original 1961-1990 NSRDB. That model is no longer compatible with cloud observations reported by the National Weather Service. We have also included a satellite-based model that will increase the spatial resolution of solar radiation for GIS or mapping applications. Work also included development of improved estimates for aerosols, water vapor, and ozone. High-quality solar measurements were obtained for 33 sites near National Weather Service stations, and model runs were completed for test years 1999 and 2000.

  8. Workshop Report on Managing Solar Radiation

    NASA Technical Reports Server (NTRS)

    Lane, Lee (Compiler); Caldeira, Ken (Compiler); Chatfield, Robert (Compiler); Langhoff, Stephanie (Compiler)

    2007-01-01

    The basic concept of managing Earth's radiation budget is to reduce the amount of incoming solar radiation absorbed by the Earth so as to counterbalance the heating of the Earth that would otherwise result from the accumulation of greenhouse gases. The workshop did not seek to decide whether or under what circumstances solar radiation management should be deployed or which strategies or technologies might be best, if it were deployed. Rather, the workshop focused on defining what kinds of information might be most valuable in allowing policy makers more knowledgeably to address the various options for solar radiation management.

  9. Coordinated weather balloon solar radiation measurements during a solar eclipse.

    PubMed

    Harrison, R G; Marlton, G J; Williams, P D; Nicoll, K A

    2016-09-28

    Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. PMID:27550757

  10. Mathematical modelling of solar ultraviolet radiation induced optical degradation in anodized aluminum

    NASA Technical Reports Server (NTRS)

    Ruley, John D.

    1986-01-01

    In the design of spacecraft for proper thermal balance, accurate information on the long-term optical behavior of the spacecraft outer skin materials is necessary. A phenomenological model for such behavior is given. The underlying principles are explained and some examples are given of the model's fit to actual measurements under simulated Earth-orbit conditions. Comments are given on the applicability of the model to materials testing and thermal modelling.

  11. The influence of solar spectral variations on global radiative balance

    NASA Astrophysics Data System (ADS)

    Gao, Feng-Ling; Tao, Le-Ren; Cui, Guo-Min; Xu, Jia-Liang; Hua, Tse-Chao

    2015-01-01

    The total solar irradiance (TSI) has been the sole solar input in many climate models for lack of long and reliable time series of solar spectral irradiance (SSI) measurements currently. However, based on the recent SSI measurements by the Solar Radiation and Climate Experiment, which is able to provide full and accurate SSI measurements, the influence of SSI variations on global radiative balance between the descending phase of previous solar cycle in December 2007 and the ascending phase of the current solar cycle in the first half 2010 has been studied in this paper. The results show that the relatively larger TSI in the first half 2010 was mainly due to the ultraviolet and near infrared radiation enhancements, with average increases of 0.11% in 200-400 nm and 0.05% in 760-4000 nm respectively, while the radiation in visible region of 400-760 nm decreased by 0.05%. According to the measurements of ozone from the Aura-Microwave Limb Sounder satellite, the global average stratospheric ozone increased markedly in the layer of 25-40 km at the same time. The visible radiation decrease and stratospheric ozone increase together contributed to the smaller solar radiation at the tropopause for each month of the first half 2010 as compared with that in December 2007, with the maximum decrease of 0.15 W m-2 in March 2010. The study reveals that SSI variations in the ascending solar phase may also cool the Earth-atmosphere system.

  12. Solar Modulation of Inner Trapped Belt Radiation Dose Rate

    NASA Astrophysics Data System (ADS)

    Diaz, Abel

    2002-03-01

    The two steady sources of radiation in low Earth orbit are the inner trapped-belt and galactic cosmic radiation (GCR), which present a very significant hazard to the astronauts and flight equipment electronics. The fluxes of GCR and inner trapped-belt particles at a fixed altitude are modulated by solar activity. They decrease with increasing solar activity in general. The mechanism of these two sources of radiation are, however, very different. In this project we shall be concerned with modeling the inner trapped-belt protons. The existing trapped-belt models, namely AP-8 is based on data acquired prior to 1970 during solar cycle 20 with relatively low solar flux. These models describe the environment at solar minimum and solar maximum only. Cycles 21 and 22 were much larger, but no valid radiation model exists for such large values. Moreover, the existing models like AP-8, CRRESPRO, and GOST describe the flux to an accuracy of a factor of two to five. There is clear need to accurately predict radiation exposure of astronauts and equipment at all times between the solar minimum and solar maximum, not only on the short duration Space Shuttle flights, but also the longer term stay onboard the International Space Station. In our approach we are taking into account some important parameters, which are responsible for energy losses of protons within the belts. These energy losses are primarily to electrons and by collisions to atmospheric nuclei. Accordingly the atmospheric density dependence at a certain altitude during a specific solar activity is an important parameter that needs to be accurately incorporated into a realistic model. We are involved in developing such a model, which would enable us to predict the radiation exposure for all occasions.

  13. Solar Radiation Research Laboratory (Poster)

    SciTech Connect

    Stoffel, T.; Andreas, A.; Reda, I.; Dooraghi, M.; Habte, A.; Kutchenreiter, M.; Wilcox, S.

    2012-07-01

    SunShot Initiative awardee posters describing the different technologies within the four subprograms of the DOE Solar Program (Photovoltaics, Concentrating Solar Power, Soft Costs, and Systems Integration).

  14. Modeling the role of solar radiation on catchment development in semi-arid ecosystems: Sensitivity analysis under variable climate and tectonic uplift

    NASA Astrophysics Data System (ADS)

    Yetemen, O.; Flores Cervantes, J. H.; Istanbulluoglu, E.; Vivoni, E. R.

    2011-12-01

    Despite the well-documented ecologic and morphologic differences in opposing north- and south-facing slopes in most landscapes, little is known about how the eco-hydro-geomorphic feedbacks controlled by slope form, aspect, and local insolation influence the erosion rates and resulting catchment form. Our ability to predict the long-term controls of solar radiation on landscape response is currently limited. In this study, we report preliminary results from a range of numerical modeling experiments using the CHILD landscape evolution model designed to explore the imprint of solar radiation in a semi-arid climate. The ecohydrological component of the model, including soil moisture, evapotranspiration and plant dynamics, and the model capability in predicting flood frequencies have been verified using the detailed data gathered from the Sevilleta National Wildlife Refuge (SNWR) in central New Mexico, and Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona. In the simulations, the role of solar radiation is examined under the forcing of constant and cyclic (Milankovitch-type wet and dry cycles) climate and variable uplift. For comparison purposes, simulations are repeated with uniform solar radiation over the domain. Our preliminary findings show a distinct signature of aspect-driven insolation on soil moisture, plant cover, runoff response, and local erosion rates, leading to steeper north-facing slopes and valley asymmetry. These effects are enhanced with higher rates of uplift due to the development of steeper slopes. Model simulations illustrate how subtle difference in annual evaporative fluxes on opposing north- and south-facing slopes lead to distinct geomorphic differences at both hillslope and catchment scales.

  15. Integrated Solar Concentrator and Shielded Radiator

    NASA Technical Reports Server (NTRS)

    Clark, David Larry

    2010-01-01

    A shielded radiator is integrated within a solar concentrator for applications that require protection from high ambient temperatures with little convective heat transfer. This innovation uses a reflective surface to deflect ambient thermal radiation, shielding the radiator. The interior of the shield is also reflective to provide a view factor to deep space. A key feature of the shield is the parabolic shape that focuses incoming solar radiation to a line above the radiator along the length of the trough. This keeps the solar energy from adding to the radiator load. By placing solar cells along this focal line, the concentration of solar energy reduces the number and mass of required cells. By shielding the radiator, the effective reject temperature is much lower, allowing lower radiator temperatures. This is particularly important for lower-temperature processes, like habitat heat rejection and fuel cell operations where a high radiator temperature is not feasible. Adding the solar cells in the focal line uses the concentrating effect of the shield to advantage to accomplish two processes with a single device. This shield can be a deployable, lightweight Mylar structure for compact transport.

  16. Solar radiation pressure effects on the Helios spacecraft

    NASA Technical Reports Server (NTRS)

    Georgevic, R. M.

    1976-01-01

    A mathematical model of the solar radiation force and torques, developed for the Mariner 10 Venus/Mercury spacecraft mission, was used for a detailed analysis of the effects of solar light pressure on the Helios spacecraft. Due to the fact that the main body of the Helios spacecraft is a surface of enclosure, inside of which most of the reradiated thermal energy is lost, expressions for the portion of the solar radiation force, produced by the thermal reradiation, had to be given a different form. Hence the need for the derivation of a somewhat different theoretical model for the force acting on the main body of the spacecraft.

  17. A model for solar constant secular changes

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth H.

    1988-01-01

    In this paper, contrast models for solar active region and global photospheric features are used to reproduce the observed Active Cavity Radiometer and Earth Radiation Budget secular trends in reasonably good fashion. A prediction for the next decade of solar constant variations is made using the model. Secular trends in the solar constant obtained from the present model support the view that the Maunder Minimum may be related to the Little Ice Age of the 17th century.

  18. Spectral distribution of solar radiation

    NASA Technical Reports Server (NTRS)

    Mecherikunnel, A. T.; Richmond, J.

    1980-01-01

    Available quantitative data on solar total and spectral irradiance are examined in the context of utilization of solar irradiance for terrestrial applications of solar energy. The extraterrestrial solar total and spectral irradiance values are also reviewed. Computed values of solar spectral irradiance at ground level for different air mass values and various levels of atmospheric pollution or turbidity are presented. Wavelengths are given for computation of solar, absorptance, transmittance and reflectance by the 100 selected-ordinate method and by the 50 selected-ordinate method for air mass 1.5 and 2 solar spectral irradiance for the four levels of atmospheric pollution.

  19. Solar radiation data manual for flat-plate and concentrating collectors

    NASA Astrophysics Data System (ADS)

    Dunlap, M. A.

    For designers and engineers of solar energy-related systems, the Solar Radiation Data Manual for Flat-Plate and Concentrating Collectors gives the solar resource available for various types of collectors for the US and its territories. The data in the manual were modeled using hourly values of direct beam and diffuse horizontal solar radiation from the National Solar Radiation Data Base (NSRDB). The NSRDB contains modeled (93%) and measured (7%) global horizontal, diffuse horizontal, and direct beam solar radiation for 1961-1990.

  20. Solar and Infrared Radiation Station (SIRS) Handbook

    SciTech Connect

    Stoffel, T

    2005-07-01

    The Solar Infrared Radiation Station (SIRS) provides continuous measurements of broadband shortwave (solar) and longwave (atmospheric or infrared) irradiances for downwelling and upwelling components. The following six irradiance measurements are collected from a network of stations to help determine the total radiative flux exchange within the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility: • Direct normal shortwave (solar beam) • Diffuse horizontal shortwave (sky) • Global horizontal shortwave (total hemispheric) • Upwelling shortwave (reflected) • Downwelling longwave (atmospheric infrared) • Upwelling longwave (surface infrared)

  1. A simple solar radiation index for wildlife habitat studies

    USGS Publications Warehouse

    Keating, Kim A.; Gogan, Peter J.; Vore, John N.; Irby, Lynn R.

    2007-01-01

    Solar radiation is a potentially important covariate in many wildlife habitat studies, but it is typically addressed only indirectly, using problematic surrogates like aspect or hillshade. We devised a simple solar radiation index (SRI) that combines readily available information about aspect, slope, and latitude. Our SRI is proportional to the amount of extraterrestrial solar radiation theoretically striking an arbitrarily oriented surface during the hour surrounding solar noon on the equinox. Because it derives from first geometric principles and is linearly distributed, SRI offers clear advantages over aspect-based surrogates. The SRI also is superior to hillshade, which we found to be sometimes imprecise and ill-behaved. To illustrate application of our SRI, we assessed niche separation among 3 ungulate species along a single environmental axis, solar radiation, on the northern Yellowstone winter range. We detected no difference between the niches occupied by bighorn sheep (Ovis canadensis) and elk (Cervus elaphus; P = 0.104), but found that mule deer (Odocoileus hemionus) tended to use areas receiving more solar radiation than either of the other species (P < 0.001). Overall, our SRI provides a useful metric that can reduce noise, improve interpretability, and increase parsimony in wildlife habitat models containing a solar radiation component.

  2. Model for the accumulation of solar wind radiation damage effects in lunar dust grains, based on recent results concerning implantation and erosion effects

    SciTech Connect

    Borg, J.; Bibring, J.P.; Cowsik, G.; Langevin, Y.; Maurette, M.

    1983-02-15

    In this paper we present our most recent results on ion implantation and erosion effects, intended to reproduce the superficial amorphous layers of radiation damage observed with a high voltage electron microscope on ..mu..m-sized grains extracted from the lunar regolith and which result from the exposure of the grains to the solar wind. We next outline theoretical computations which yield the thickness distribution of such amorphous layers as a function of the exposure time of the grains at the surface of the moon, the He/H ratio, and the speed distribution in the solar wind. From this model, the position of the peak in the solar wind speed distribution is the major parameter controlling the thickness of the amorphous layer.

  3. High Radiation Resistance IMM Solar Cell

    NASA Technical Reports Server (NTRS)

    Pan, Noren

    2015-01-01

    Due to high launch costs, weight reduction is a key driver for the development of new solar cell technologies suitable for space applications. This project is developing a unique triple-junction inverted metamorphic multijunction (IMM) technology that enables the manufacture of very lightweight, low-cost InGaAsP-based multijunction solar cells. This IMM technology consists of indium (In) and phosphorous (P) solar cell active materials, which are designed to improve the radiation-resistant properties of the triple-junction solar cell while maintaining high efficiency. The intrinsic radiation hardness of InP materials makes them of great interest for building solar cells suitable for deployment in harsh radiation environments, such as medium Earth orbit and missions to the outer planets. NASA Glenn's recently developed epitaxial lift-off (ELO) process also will be applied to this new structure, which will enable the fabrication of the IMM structure without the substrate.

  4. Mariner Venus/Mercury 1973 solar radiation force and torques

    NASA Technical Reports Server (NTRS)

    Georgevic, R. M.

    1974-01-01

    The need for an improvement of the mathematical model of the solar radiation force and torques for the Mariner Venus/Mercury spacecraft arises from the fact that this spacecraft will be steering toward the inner planets (Venus and Mercury), where, due to the proximity of the Sun, the effect of the solar radiation pressure is much larger than it was on the antecedent Mariner spacecraft, steering in the opposite direction. Therefore, although the model yielded excellent results in the case of the Mariner 9 Mars Orbiter, additional effects of negligible magnitudes for the previous missions of the Mariner spacecraft should now be included in the model. This study examines all such effects and incorporates them into the already existing model, as well as using the improved model for calculation of the solar radiation force and torques acting on the Mariner Venus/Mercury spacecraft.

  5. Effects of solar radiation on glass

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Kinser, Donald L.

    1991-01-01

    The effects of solar radiation of selected glasses are reported. Optical property degradation is studied using UV-Vis spectrophotometry. Strength changes are measured using a concentric ring bend test. Direct fracture toughness measurements using an indentation test are planned.

  6. Solar-Radiation Measuring Equipment and Glossary

    NASA Technical Reports Server (NTRS)

    Carter, E. A.; Patel, A. M.; Greenbaum, S. A.

    1982-01-01

    1976 listing of commercially available solar-radiation measuring equipment is presented in 50-page report. Sensor type, response time, cost data, and comments concerning specifications and intended usage are listed for 145 instruments from 38 manufactures.

  7. Estimation of atmospheric turbidity and surface radiative parameters using broadband clear sky solar irradiance models in Rio de Janeiro-Brasil

    NASA Astrophysics Data System (ADS)

    Flores, José L.; Karam, Hugo A.; Marques Filho, Edson P.; Pereira Filho, Augusto J.

    2016-02-01

    The main goal of this paper is to estimate a set of optimal seasonal, daily, and hourly values of atmospheric turbidity and surface radiative parameters Ångström's turbidity coefficient ( β), Ångström's wavelength exponent ( α), aerosol single scattering albedo ( ω o ), forward scatterance ( F c ) and average surface albedo ( ρ g ), using the Brute Force multidimensional minimization method to minimize the difference between measured and simulated solar irradiance components, expressed as cost functions. In order to simulate the components of short-wave solar irradiance (direct, diffuse and global) for clear sky conditions, incidents on a horizontal surface in the Metropolitan Area of Rio de Janeiro (MARJ), Brazil (22° 51' 27″ S, 43° 13' 58″ W), we use two parameterized broadband solar irradiance models, called CPCR2 and Iqbal C, based on synoptic information. The meteorological variables such as precipitable water ( u w ) and ozone concentration ( u o ) required by the broadband solar models were obtained from moderate-resolution imaging spectroradiometer (MODIS) sensor on Terra and Aqua NASA platforms. For the implementation and validation processes, we use global and diffuse solar irradiance data measured by the radiometric platform of LabMiM, located in the north area of the MARJ. The data were measured between the years 2010 and 2012 at 1-min intervals. The performance of solar irradiance models using optimal parameters was evaluated with several quantitative statistical indicators and a subset of measured solar irradiance data. Some daily results for Ångström's wavelength exponent α were compared with Ångström's parameter (440-870 nm) values obtained by aerosol robotic network (AERONET) for 11 days, showing an acceptable level of agreement. Results for Ångström's turbidity coefficient β, associated with the amount of aerosols in the atmosphere, show a seasonal pattern according with increased precipitation during summer months (December

  8. An improvement of the IGMK model to derive total and diffuse solar radiation at the surface from satellite data

    SciTech Connect

    Stuhlmann, R.; Rieland, M.; Raschke, E. )

    1990-07-01

    The IGMK model was developed by Moeser and Raschke (1983) to determine global radiation from GEO satellite data; this paper presents some improvements of IGMK including a totally new treatment of cloud transmittance in combination with the clear-sky atmospheric state. This new algorithm explicitly accounts for multiple reflections between surface and atmospheric layers, which is most important for the diffuse component of global radiation. With the new IGMK model, the diffuse component of the global radiation can be derived from satellite data. The clear-sky background atmospheric treatment also includes more variables, which account for regional and temporal variations of all atmospheric constituents as well as the dependence of incoming radiation on the elevation of the surface. By use of Meteosat ISCCP-B2 it is demonstrated that, over a period of 2 years, the deviations between the IGMK model results and surface measurements are less than 10 percent. 35 refs.

  9. Solar ultraviolet radiation: definitions and terminology.

    PubMed

    Matts, Paul J

    2006-01-01

    In the rapidly developing field of photobiology as it relates to solar ultraviolet radiation (UVR), there is a need as never before to ensure that definitions and terminology are current, correct, and standard. This article provides a basic definition of UVR; a review of correct UVR radiometric symbols, units, and nomenclature; defines extraterrestrial and terrestrial solar UVR; and reviews the measurement of biologically effective dose of solar UVR in humans. PMID:16311162

  10. Commission 12: Solar Radiation and Structure

    NASA Astrophysics Data System (ADS)

    Cauzzi, Gianna; Shchukina, Nataliya; Kosovichev, Alexander; Bianda, Michele; Brandenburg, Axel; Chou, Dean-Yi; Dasso, Sergio; Ding, Ming-De; Jefferies, Stuart; Krivova, Natalie; Kuznetsov, Vladimir D.; Moreno-Insertis, Fernando

    2016-04-01

    Commission 12 of the International Astronomical Union encompasses investigations of the internal structure and dynamics of the Sun, the quiet solar atmosphere, solar radiation and its variability, and the nature of relatively stable magnetic structures like sunspots, faculae and the magnetic network. The Commission sees participation of over 300 scientists worldwide.

  11. RADIATIVE HEATING OF THE SOLAR CORONA

    SciTech Connect

    Moran, Thomas G.

    2011-10-20

    We investigate the effect of solar visible and infrared radiation on electrons in the Sun's atmosphere using a Monte Carlo simulation of the wave-particle interaction and conclude that sunlight provides at least 40% and possibly all of the power required to heat the corona, with the exception of dense magnetic flux loops. The simulation uses a radiation waveform comprising 100 frequency components spanning the solar blackbody spectrum. Coronal electrons are heated in a stochastic manner by low coherence solar electromagnetic radiation. The wave 'coherence time' and 'coherence volume' for each component is determined from optical theory. The low coherence of solar radiation allows moving electrons to gain energy from the chaotic wave field which imparts multiple random velocity 'kicks' to these particles causing their velocity distribution to broaden or heat. Monte Carlo simulations of broadband solar radiative heating on ensembles of 1000 electrons show heating at per particle levels of 4.0 x 10{sup -21} to 4.0 x 10{sup -20} W, as compared with non-loop radiative loss rates of {approx}1 x 10{sup -20} W per electron. Since radiative losses comprise nearly all of the power losses in the corona, sunlight alone can explain the elevated temperatures in this region. The volume electron heating rate is proportional to density, and protons are assumed to be heated either by plasma waves or through collisions with electrons.

  12. Near-Earth Space Radiation Models

    NASA Technical Reports Server (NTRS)

    Xapsos, Michael A.; O'Neill, Patrick M.; O'Brien, T. Paul

    2012-01-01

    Review of models of the near-Earth space radiation environment is presented, including recent developments in trapped proton and electron, galactic cosmic ray and solar particle event models geared toward spacecraft electronics applications.

  13. The Potential of Heat Collection from Solar Radiation in Asphalt Solar Collectors in Malaysia

    NASA Astrophysics Data System (ADS)

    Beddu, Salmia; Talib, Siti Hidayah Abdul; Itam, Zarina

    2016-03-01

    The implementation of asphalt solar collectors as a means of an energy source is being widely studied in recent years. Asphalt pavements are exposed to daily solar radiation, and are capable of reaching up to 70°C in temperature. The potential of harvesting energy from solar pavements as an alternative energy source in replace of non-renewable energy sources prone to depletion such as fuel is promising. In Malaysia, the sun intensity is quite high and for this reason, absorbing the heat from sun radiation, and then utilizing it in many other applications such as generating electricity could definitely be impressive. Previous researches on the different methods of studying the effect of heat absorption caused by solar radiation prove to be quite old and inaffective. More recent findings, on the otherhand, prove to be more informative. This paper focuses on determining the potential of heat collection from solar radiation in asphalt solar collectors using steel piping. The asphalt solar collector model constructed for this research was prepared in the civil engineering laboratory. The hot mixed asphalt (HMA) contains 10% bitumen mixed with 90% aggregates of the total size of asphalt. Three stainless steel pipes were embedded into the interior region of the model according to the design criteria, and then put to test. Results show that harvesting energy from asphalt solar collectors proves highly potential in Malaysia due its the hot climate.

  14. Excitation of XUV radiation in solar flares

    NASA Technical Reports Server (NTRS)

    Emslie, A. Gordon

    1992-01-01

    The goal of the proposed research was to understand the means by which XUV radiation in solar flares is excited, and to use this radiation as diagnostics of the energy release and transport processes occurring in the flare. Significant progress in both of these areas, as described, was made.

  15. Solar Furnance Model

    ERIC Educational Resources Information Center

    Palmer, Dennis L.; Olsen, Richard W.

    1977-01-01

    Described is how to build a solar furnace model. A detailed list of materials and methods are included along with diagrams. This particular activity is part of an audiotutorial unit concerned with the energy crisis and energy alternatives. (MA)

  16. Solar Radiation and Climate Experiment (SORCE) Satellite

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This is a close-up of the NASA-sponsored Solar Radiation and Climate Experiment (SORCE) Satellite. The SORCE mission, launched aboard a Pegasus rocket January 25, 2003, will provide state of the art measurements of incoming x-ray, ultraviolet, visible, near-infrared, and total solar radiation. Critical to studies of the Sun and its effect on our Earth system and mankind, SORCE will provide measurements that specifically address long-term climate change, natural variability and enhanced climate prediction, and atmospheric ozone and UV-B radiation. Orbiting around the Earth accumulating solar data, SORCE measures the Sun's output with the use of state-of-the-art radiometers, spectrometers, photodiodes, detectors, and bolo meters engineered into instruments mounted on a satellite observatory. SORCE is carrying 4 instruments: The Total Irradiance Monitor (TIM); the Solar Stellar Irradiance Comparison Experiment (SOLSTICE); the Spectral Irradiance Monitor (SIM); and the XUV Photometer System (XPS).

  17. The effects of solar radiation and black body re-radiation on thermal comfort.

    PubMed

    Hodder, Simon; Parsons, Ken

    2008-04-01

    When the sun shines on people in enclosed spaces, such as in buildings or vehicles, it directly affects thermal comfort. There is also an indirect effect as surrounding surfaces are heated exposing a person to re-radiation. This laboratory study investigated the effects of long wave re-radiation on thermal comfort, individually and when combined with direct solar radiation. Nine male participants (26.0 +/- 4.7 years) took part in three experimental sessions where they were exposed to radiation from a hot black panel heated to 100 degrees C; direct simulated solar radiation of 600 Wm(-2) and the combined simulated solar radiation and black panel radiation. Exposures were for 30 min, during which subjective responses and mean skin temperatures were recorded. The results showed that, at a surface temperature of 100 degrees C (close to maximum in practice), radiation from the flat black panel provided thermal discomfort but that this was relatively small when compared with the effects of direct solar radiation. It was concluded that re-radiation, from a dashboard in a vehicle, for example, will not have a major direct influence on thermal comfort and that existing models of thermal comfort do not require a specific modification. These results showed that, for the conditions investigated, the addition of re-radiation from internal components has an effect on thermal sensation when combined with direct solar radiation. However, it is not considered that it will be a major factor in a real world situation. This is because, in practice, dashboards are unlikely to maintain very high surface temperatures in vehicles without an unacceptably high air temperature. This study quantifies the contribution of short- and long-wave radiation to thermal comfort. The results will aid vehicle designers to have a better understanding of the complex radiation environment. These include direct radiation from the sun as well as re-radiation from the dashboard and other internal surfaces

  18. Prediction of Solar Radiation on Building Rooftops: A Data-Mining Approach

    SciTech Connect

    Omitaomu, Olufemi A; Bhaduri, Budhendra L; Kodysh, Jeffrey B

    2012-01-01

    Solar energy technologies offer a clean, renewable, and domestic energy source, and are essential components of a sustainable energy future. The accurate measurement of solar radiation data is essential for optimum site selection of future distributed solar power plants as well as sizing photovoltaic systems. However, solar radiation data are not readily available because measured sequences of radiation values are obtained for a few locations in a country. When the data are available, they are usually at different time periods and spatial scale. The availability of solar radiation data at hourly or daily time scale will enhance the integration of solar energy into electricity generation and promote a sustainable energy future. The ability to generate approximate solar radiation values is often the only practical way to obtain radiation data at hourly or daily time scale. As a result, several models have been developed for estimating solar radiation values based on analytical, numerical simulation, and statistical approaches. However, these models have inherent challenges. We will discuss some of those challenges in this paper. To enhance the prediction of solar radiation values, a novel approach is presented for estimating solar radiation values using support vector machine technique. The approach accounts for unique characteristics that influence solar radiation values. The preliminary results obtained offer useful insights for model enhancements.

  19. Solar radiation decreases parasitism in Daphnia.

    PubMed

    Overholt, Erin P; Hall, Spencer R; Williamson, Craig E; Meikle, Claire K; Duffy, Meghan A; Cáceres, Carla E

    2012-01-01

    Climate change and variation in atmospheric ozone are influencing the intensity of ultraviolet radiation (UVR) reaching ecosystems. Changing UVR regimes, in turn, may alter epidemics of infectious disease. This possibility hinges on the sensitivity of epidemiologically relevant traits of host and parasite to UVR. We address this issue using a planktonic system (a zooplankton host, Daphnia dentifera, and its virulent fungal parasite, Metschnikowia bicuspidata). Controlled laboratory experiments, coupled with in situ field incubations of spores, revealed that quite low levels of UVR (as well as longer wavelength light) sharply reduced the infectivity of fungal spores but did not affect host susceptibility to infection. The parasite's sensitivity to solar radiation may underlie patterns in a lake survey: higher penetration of solar radiation into lakes correlated with smaller epidemics that started later in autumn (as incident sunlight declined). Thus, solar radiation, by diminishing infectivity of the parasite, may potently reduce disease. PMID:22034950

  20. Solar Sail Model Validation from Echo Trajectories

    NASA Technical Reports Server (NTRS)

    Heaton, Andrew F.; Brickerhoff, Adam T.

    2007-01-01

    The NASA In-Space Propulsion program has been engaged in a project to increase the technology readiness of solar sails. Recently, these efforts came to fruition in the form of several software tools to model solar sail guidance, navigation and control. Furthermore, solar sails are one of five technologies competing for the New Millennium Program Space Technology 9 flight demonstration mission. The historic Echo 1 and Echo 2 balloons were comprised of aluminized Mylar, which is the near-term material of choice for solar sails. Both spacecraft, but particularly Echo 2, were in low Earth orbits with characteristics similar to the proposed Space Technology 9 orbit. Therefore, the Echo balloons are excellent test cases for solar sail model validation. We present the results of studies of Echo trajectories that validate solar sail models of optics, solar radiation pressure, shape and low-thrust orbital dynamics.

  1. Solar Position Algorithm for Solar Radiation Applications (Revised)

    SciTech Connect

    Reda, I.; Andreas, A.

    2008-01-01

    This report is a step-by-step procedure for implementing an algorithm to calculate the solar zenith and azimuth angles in the period from the year -2000 to 6000, with uncertainties of ?0.0003/. It is written in a step-by-step format to simplify otherwise complicated steps, with a focus on the sun instead of the planets and stars in general. The algorithm is written in such a way to accommodate solar radiation applications.

  2. Comparison of hourly solar radiation from ground-based station, remote sensing sensors and weather forecast models: A preliminary study, in a coastal site of South Italy (Lamezia Terme).

    NASA Astrophysics Data System (ADS)

    Lo Feudo, Teresa; Avolio, Elenio; Gullì, Daniel; Federico, Stefano; Sempreviva, Annamaria; Calidonna, Claudia Roberta

    2015-04-01

    The solar radiation is a very complex parameter to cope with due to its random and nonlinear characteristics depending on changeable weather conditions and complex orography. Therefore it is a critical input parameter to address many climatic, meteorological, and solar energy issues. In this preliminary study we made an intercomparison between the hourly solar MSG SEVIRI (Meteosat Second Generation Spinning Enhanced Visible and Infrared) data product DSSF(Down-welling Surface Short-wave Flux) developed by LSA SAF( Land Surface Analysis Satellite Application Facility), a pyranometer sensor (CNR 4 Net Radiometer - Kipp&Zonen) and two weather forecast models. The solar radiation datasets were obtained from a pyranometer sensor situated in Weather Station of CNR ISAC Lamezia Terme(38,88 LAT 16,24 LON), a satellite based product DSSF with spatial resolution of 3km and outputs of two weather forecast models. Models adopted are WRF(Weather Research and Forecasting) and Rams( Regional Atmospheric Modeling System)running operatively with a 3Km horizontal resolution. Both DSSF and model outputs are extracted at Latitude and Longitude previously defined. The solar radiation performance and accuracy are evaluated for datasets segmented into two atmospheric conditions clear and cloudy sky, and both conditions, additionally, for a quantitative analysis the exact acquisition times of satellite measurements was taken into account. The RMSE and BIAS for hourly, daily and monthly - averaged solar radiation are estimated including clear and sky conditions and snow or ice cover. Comparison between DSSF product, Solar Radiation ground based pyranometer measurements and output of two weather forecast models, made over the period June2013-December2013, showed a good agreement in this costal site and we demonstrated that the forecast models generally overestimate solar radiation respect the ground based sensor and DSSF product. As results in general the RMSE monthly-averaged are

  3. Parameterization of cloud effects on the absorption of solar radiation

    NASA Technical Reports Server (NTRS)

    Davies, R.

    1983-01-01

    A radiation parameterization for the NASA Goddard climate model was developed, tested, and implemented. Interactive and off-hire experiments with the climate model to determine the limitations of the present parameterization scheme are summarized. The parameterization of Cloud absorption in terms of solar zeith angle, column water vapors about the cloud top, and cloud liquid water content is discussed.

  4. Gallium arsenide solar cell radiation damage study

    NASA Technical Reports Server (NTRS)

    Maurer, R. H.; Herbert, G. A.; Kinnison, J. D.; Meulenberg, A.

    1989-01-01

    A thorough analysis has been made of electron- and proton- damaged GaAs solar cells suitable for use in space. It is found that, although some electrical parametric data and spectral response data are quite similar, the type of damage due to the two types of radiation is different. An I-V analysis model shows that electrons damage the bulk of the cell and its currents relatively more, while protons damage the junction of the cell and its voltages more. It is suggested that multiple defects due to protons in a strong field region such as a p/n junction cause the greater degradation in cell voltage, whereas the individual point defects in the quasi-neutral minority-carrier-diffusion regions due to electrons cause the greater degradation in cell current and spectral response.

  5. Spectral estimates of solar radiation intercepted by corn canopies

    NASA Technical Reports Server (NTRS)

    Bauer, M. E. (Principal Investigator); Daughtry, C. S. T.; Gallo, K. P.

    1982-01-01

    Reflectance factor data were acquired with a Landsat band radiometer throughout two growing seasons for corn (Zea mays L.) canopies differing in planting dates, populations, and soil types. Agronomic data collected included leaf area index (LAI), biomass, development stage, and final grain yields. The spectral variable, greenness, was associated with 78 percent of the variation in LAI over all treatments. Single observations of LAI or greenness have limited value in predicting corn yields. The proportions of solar radiation intercepted (SRI) by these canopies were estimated using either measured LAI or greenness. Both SRI estimates, when accumulated over the growing season, accounted for approximately 65 percent of the variation in yields. Models which simulated the daily effects of weather and intercepted solar radiation on growth had the highest correlations to grain yields. This concept of estimating intercepted solar radiation using spectral data represents a viable approach for merging spectral and meteorological data for crop yield models.

  6. Influence of Solar and Thermal Radiation on Future Heat Stress Using CMIP5 Archive Driving the Community Land Model Version 4.5

    NASA Astrophysics Data System (ADS)

    Buzan, J. R.; Huber, M.

    2015-12-01

    The summer of 2015 has experienced major heat waves on 4 continents, and heat stress left ~4000 people dead in India and Pakistan. Heat stress is caused by a combination of meteorological factors: temperature, humidity, and radiation. The International Organization for Standardization (ISO) uses Wet Bulb Globe Temperature (WBGT)—an empirical metric this is calibrated with temperature, humidity, and radiation—for determining labor capacity during heat stress. Unfortunately, most literature studying global heat stress focuses on extreme temperature events, and a limited number of studies use the combination of temperature and humidity. Recent global assessments use WBGT, yet omit the radiation component without recalibrating the metric.Here we explicitly calculate future WBGT within a land surface model, including radiative fluxes as produced by a modeled globe thermometer. We use the Community Land Model version 4.5 (CLM4.5), which is a component model of the Community Earth System Model (CESM), and is maintained by the National Center for Atmospheric Research (NCAR). To drive our CLM4.5 simulations, we use greenhouse gasses Representative Concentration Pathway 8.5 (business as usual), and atmospheric output from the CMIP5 Archive. Humans work in a variety of environments, and we place the modeled globe thermometer in a variety of environments. We modify CLM4.5 code to calculate solar and thermal radiation fluxes below and above canopy vegetation, and in bare ground. To calculate wet bulb temperature, we implemented the HumanIndexMod into CLM4.5. The temperature, wet bulb temperature, and radiation fields are calculated at every model time step and are outputted 4x Daily. We use these fields to calculate WBGT and labor capacity for two time slices: 2026-2045 and 2081-2100.

  7. Predictions of solar radiation distribution: Global, direct and diffuse light on horizontal surface

    NASA Astrophysics Data System (ADS)

    Chabane, Foued; Moummi, Noureddine; Brima, Abdelhafid

    2016-04-01

    Solar radiation models for predicting the average daily and hourly global radiation, direct and diffuse radiation are discussed in this paper. The average daily global radiation in Ghardaia (32.38 N latitude, 3.82 E longitude) is predicted. Estimations of monthly average hourly global radiation are considered. We have developed this correlation using the sunlight and global radiation data from one year location around the weather station in Ghardaia. Two predictions of solar radiation distribution: direct and diffuse light on a horizontal area models, are reviewed to predict the hourly irradiation of Ghardaia utilizing the approach such as regression models. Comparisons between model predictions with measured data are made.

  8. Climate response to imposed solar radiation reductions in high latitudes

    NASA Astrophysics Data System (ADS)

    MacCracken, M. C.; Shin, H.-J.; Caldeira, K.; Ban-Weiss, G. A.

    2012-07-01

    Increasing concentrations of greenhouse gases are the primary contributor to the 0.8 °C increase in the global average temperature since the late 19th century, shortening cold seasons and lengthening warm seasons. The warming is amplified in polar regions, causing retreat of sea ice, snow cover, permafrost, mountain glaciers, and ice sheets, while also modifying mid-latitude weather, amplifying global sea level rise, and initiating high-latitude carbon feedbacks. Model simulations in which we reduced solar insolation over high latitudes not only cooled those regions, but also drew energy from lower latitudes, exerting a cooling influence over much of the hemisphere in which the reduction was imposed. Our simulations, which used the National Center for Atmospheric Research's CAM3.1 atmospheric model coupled to a slab ocean, indicated that, on a normalized basis, high-latitude reductions in absorbed solar radiation have a significantly larger cooling influence than equivalent solar reductions spread evenly over the Earth. This amplified influence occurred because high-latitude surface cooling preferentially increased sea ice fraction and, therefore, surface albedo, leading to a larger deficit in the radiation budget at the top of the atmosphere than from an equivalent global reduction in solar radiation. Reductions in incoming solar radiation in one polar region (either north or south) resulted in increased poleward energy transport during that hemisphere's cold season and shifted the Inter-Tropical Convergence Zone (ITCZ) away from that pole, whereas equivalent reductions in both polar regions tended to leave the ITCZ approximately in place. Together, these results suggest that, until emissions reductions are sufficient to limit the warming influence of greenhouse gas concentrations, polar reductions in solar radiation, if they can be efficiently and effectively implemented, might, because of fewer undesirable side effects than for global solar radiation reductions

  9. A simplified solar cell array modelling program

    NASA Technical Reports Server (NTRS)

    Hughes, R. D.

    1982-01-01

    As part of the energy conversion/self sufficiency efforts of DSN engineering, it was necessary to have a simplified computer model of a solar photovoltaic (PV) system. This article describes the analysis and simplifications employed in the development of a PV cell array computer model. The analysis of the incident solar radiation, steady state cell temperature and the current-voltage characteristics of a cell array are discussed. A sample cell array was modelled and the results are presented.

  10. Solar Radiation on Mars: Tracking Photovoltaic Array

    NASA Technical Reports Server (NTRS)

    Appelbaum, Joseph; Flood, Dennis J.; Crutchik, Marcos

    1994-01-01

    A photovoltaic power source for surface-based operation on Mars can offer many advantages. Detailed information on solar radiation characteristics on Mars and the insolation on various types of collector surfaces are necessary for effective design of future planned photovoltaic systems. In this article we have presented analytical expressions for solar radiation calculation and solar radiation data for single axis (of various types) and two axis tracking surfaces and compared the insulation to horizontal and inclined surfaces. For clear skies (low atmospheric dust load) tracking surfaces resulted in higher insolation than stationary surfaces, whereas for highly dusty atmospheres, the difference is small. The insolation on the different types of stationary and tracking surfaces depend on latitude, season and optical depth of the atmosphere, and the duration of system operation. These insolations have to be compared for each mission.

  11. Working group written presentation: Solar radiation

    NASA Technical Reports Server (NTRS)

    Slemp, Wayne S.

    1989-01-01

    The members of the Solar Radiation Working Group arrived at two major solar radiation technology needs: (1) generation of a long term flight data base; and (2) development of a standardized UV testing methodology. The flight data base should include 1 to 5 year exposure of optical filters, windows, thermal control coatings, hardened coatings, polymeric films, and structural composites. The UV flux and wavelength distribution, as well as particulate radiation flux and energy, should be measured during this flight exposure. A standard testing methodology is needed to establish techniques for highly accelerated UV exposure which will correlate well with flight test data. Currently, UV can only be accelerated to about 3 solar constants and can correlate well with flight exposure data. With space missions to 30 years, acceleration rates of 30 to 100X are needed for efficient laboratory testing.

  12. Chandra Radiation Environment Modeling

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Blackwell, W. C.

    2003-01-01

    CRMFLX (Chandra Radiation Model of ion FluX) is a radiation environment risk mitigation tool for use as a decision aid in planning the operations times for Chandra's Advanced CCD Imaging Spectrometer (ACIS) detector. The accurate prediction of the proton flux environment with energies of 100 - 200 keV is needed in order to protect the ACIS detector against proton degradation. Unfortunately, protons of this energy are abundant in the region of space Chandra must operate, and on-board particle detectors do not measure proton flux levels of the required energy range. This presentation will describe the plasma environment data analysis and modeling basis of the CRMFLX engineering environment model developed to predict the proton flux in the solar wind, magnetosheath, and magnetosphere phenomenological regions of geospace. The recently released CRMFLX Version 2 implementation includes an algorithm that propagates flux from an observation location to other regions of the magnetosphere based on convective ExB and VB-curvature particle drift motions. This technique has the advantage of more completely filling out the database and makes maximum use of limited data obtained during high Kp periods or in areas of the magnetosphere with poor satellite flux measurement coverage.

  13. National Solar Radiation Data Base (1961-1990), volume 2

    NASA Astrophysics Data System (ADS)

    Maxwell, Eugene L.; Marion, William F.; Myers, Daryl R.; Rymes, Martin D.; Wilcox, Stephen M.

    1995-01-01

    The 1961-1990 National Solar Radiation Data Base (NSRDB) for the United States was completed in September 1992. This was the final product of four years of work under the U.S. Department of Energy (DOE) Solar Radiation Resource Assessment Project. The NSRDB contains 30 years of hourly data for five solar radiation elements and 15 meteorological elements for 239 sites. The user's manual (NSRDB-Volume 1, 1992) for the NSRDB provides detailed information on the structure of the data base and the products that have been produced from it. Most users of the data base will find all of the information that they need in Volume 1. Volume 2 has been written primarily for researchers who need more information about the methods employed in producing the data base. In addition to research results, we have included information on practical lessons learned from this project. Therefore, Volume 2 should be of value to anyone developing a similar data base for other regions or other countries. Most of the solar radiation data in the NSRDB and the previous SOLMET (SOLar METeorological) data base were generated by computer models. Therefore, a major part of this report is centered around the METeorological/STATistical (METSTAT) model (Section 3.0), its input data (Sections 5.0 and 6.0), its use in producing the NSRDB (Sections 4.0 and 7.0), and comparisons with the models used in producing the SOLMET data base (Section 10.0).

  14. Fast dynamic processes of solar radiation

    SciTech Connect

    Tomson, Teolan

    2010-02-15

    This paper studies dynamic processes of fast-alternating solar radiation which are assessed by alternation of clouds. Most attention is devoted to clouds of type Cumulus Humilis, identified through visual recognition and/or a specially constructed automatic sensor. One second sampling period was used. Recorded data series were analyzed with regard to duration of illuminated 'windows' between shadows, their stochastic intervals, fronts and the magnitude of increments of solar irradiance. (author)

  15. LDEF solar cell radiation effects analysis

    NASA Technical Reports Server (NTRS)

    Rives, Carol J.; Azarewicz, Joseph L.; Massengill, Lloyd

    1993-01-01

    Because of the extended time that the Long Duration Exposure Facility (LDEF) mission stayed in space, the solar cells on the satellite experienced greater environments than originally planned. The cells showed an overall degradation in performance that is due to the combined effects of the various space environments. The purpose of this analysis is to calculate the effect of the accumulated radiation on the solar cells, thereby helping Marshall Space Flight Center (MSFC) to unravel the relative power degradation from the different environments.

  16. Measurement of solar radiation at the Earth's surface

    NASA Technical Reports Server (NTRS)

    Bartman, F. L.

    1982-01-01

    The characteristics of solar energy arriving at the surface of the Earth are defined and the history of solar measurements in the United States presented. Radiation and meteorological measurements being made at solar energy meteorological research and training sites and calibration procedures used there are outlined. Data illustrating the annual variation in daily solar radiation at Ann Arbor, Michigan and the diurnal variation in radiation at Albuquerque, New Mexico are presented. Direct normal solar radiation received at Albuquerque is contrasted with that received at Maynard, Massachusetts. Average measured global radiation for a period of one year for four locations under clear skies, 50% cloud cover, and 100% cloud cover is given and compared with the solar radiation at the top of the atmosphere. The May distribution of mean daily direct solar radiation and mean daily global solar radiation over the United States is presented. The effects of turbidity on the direct and circumsolar radiation are shown.

  17. Spectral Solar Radiation Data Base at NREL

    DOE Data Explorer

    The Solar Energy Research Institute (SERI)*, Electric Power Research Institute (EPRI), Florida Solar Energy Center (FSEC), and Pacific Gas and Electric Company (PG&E) cooperated to produce a spectral solar radiation data base representing a range of atmospheric conditions (or climates) that is applicable to several different types of solar collectors. Data that are included in the data base were collected at FSEC from October 1986 to April 1988, and at PG&E from April 1987 to April 1988. FSEC operated one EPRI and one SERI spectroradiometer almost daily at Cape Canaveral, which contributed nearly 2800 spectra to the data base. PG&E operated one EPRI spectroradiometer at San Ramon, Calif., as resources permitted, contributing nearly 300 spectra to the data base. SERI collected about 200 spectra in the Denver/Golden, Colo., area form November 1987 to February 1988 as part of a research project to study urban spectral solar radiation, and added these data to the data base. *In September 1991 the Solar Energy Research Institute became the National Renewable Energy Laboratory. [Description taken from http://rredc.nrel.gov/solar/old_data/spectral/

  18. Galactic and solar radiation exposure to aircrew during a solar cycle.

    PubMed

    Lewis, B J; Bennett, L G I; Green, A R; McCall, M J; Ellaschuk, B; Butler, A; Pierre, M

    2002-01-01

    An on-going investigation using a tissue-equivalent proportional counter (TEPC) has been carried out to measure the ambient dose equivalent rate of the cosmic radiation exposure of aircrew during a solar cycle. A semi-empirical model has been derived from these data to allow for the interpolation of the dose rate for any global position. The model has been extended to an altitude of up to 32 km with further measurements made on board aircraft and several balloon flights. The effects of changing solar modulation during the solar cycle are characterised by correlating the dose rate data to different solar potential models. Through integration of the dose-rate function over a great circle flight path or between given waypoints, a Predictive Code for Aircrew Radiation Exposure (PCAIRE) has been further developed for estimation of the route dose from galactic cosmic radiation exposure. This estimate is provided in units of ambient dose equivalent as well as effective dose, based on E/H x (10) scaling functions as determined from transport code calculations with LUIN and FLUKA. This experimentally based treatment has also been compared with the CARI-6 and EPCARD codes that are derived solely from theoretical transport calculations. Using TEPC measurements taken aboard the International Space Station, ground based neutron monitoring, GOES satellite data and transport code analysis, an empirical model has been further proposed for estimation of aircrew exposure during solar particle events. This model has been compared to results obtained during recent solar flare events. PMID:12430961

  19. LINEAR SOLAR MODELS

    SciTech Connect

    Villante, F. L.; Ricci, B.

    2010-05-01

    We present a new approach to studying the properties of the Sun. We consider small variations of the physical and chemical properties of the Sun with respect to standard solar model predictions and we linearize the structure equations to relate them to the properties of the solar plasma. By assuming that the (variation of) present solar composition can be estimated from the (variation of) nuclear reaction rates and elemental diffusion efficiency in the present Sun, we obtain a linear system of ordinary differential equations which can be used to calculate the response of the Sun to an arbitrary modification of the input parameters (opacity, cross sections, etc.). This new approach is intended to be a complement to the traditional methods for solar model (SM) calculation and allows us to investigate in a more efficient and transparent way the role of parameters and assumptions in SM construction. We verify that these linear solar models recover the predictions of the traditional SMs with a high level of accuracy.

  20. Analysis of the ozone profile specifications in the WRF-ARW model and their impact on the simulation of direct solar radiation

    NASA Astrophysics Data System (ADS)

    Montornès, A.; Codina, B.; Zack, J. W.

    2014-08-01

    Although ozone is an atmospheric gas with high spatial and temporal variability, mesoscale numerical weather prediction (NWP) models simplify the specification of ozone concentrations used in their shortwave schemes by using a few ozone profiles. In this paper, a two-part study is presented: (i) an assessment of the quality of the ozone profiles provided for use with the shortwave schemes in the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) model and (ii) the impact of deficiencies in those profiles on the performance of model simulations of direct solar radiation. The first part compares simplified datasets used to specify the total ozone column in five schemes (i.e. Goddard, New Goddard, RRTMG, CAM and Fu-Liou-Gu) with the Multi-Sensor Reanalysis dataset during the period 1979-2008 examining the latitudinal, longitudinal and seasonal limitations in the ozone modeling of each parameterization. The results indicate that the maximum deviations are over the poles due to the Brewer-Dobson circulation and there are prominent longitudinal patterns in the departures due to quasi-stationary features forced by the land-sea distribution. In the second part, the bias in the simulated direct solar radiation due to these deviations from the simplified spatial and temporal representation of the ozone distribution is analyzed for the New Goddard and CAM schemes using the Beer-Lambert-Bouger law. For radiative applications those simplifications introduce spatial and temporal biases with near-zero departures over the tropics during all the year and increasing poleward with a maximum in the high middle latitudes during the winter of each hemisphere.

  1. Probabilistic Solar Energetic Particle Models

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.; Dietrich, William F.; Xapsos, Michael A.

    2011-01-01

    To plan and design safe and reliable space missions, it is necessary to take into account the effects of the space radiation environment. This is done by setting the goal of achieving safety and reliability with some desired level of confidence. To achieve this goal, a worst-case space radiation environment at the required confidence level must be obtained. Planning and designing then proceeds, taking into account the effects of this worst-case environment. The result will be a mission that is reliable against the effects of the space radiation environment at the desired confidence level. In this paper we will describe progress toward developing a model that provides worst-case space radiation environments at user-specified confidence levels. We will present a model for worst-case event-integrated solar proton environments that provide the worst-case differential proton spectrum. This model is based on data from IMP-8 and GOES spacecraft that provide a data base extending from 1974 to the present. We will discuss extending this work to create worst-case models for peak flux and mission-integrated fluence for protons. We will also describe plans for similar models for helium and heavier ions.

  2. GOES Solar Radiation for Evapotranspiration Estimation and Streamflow Predictions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Weather Service River Forecast System uses the Sacramento Soil Moisture Accounting (SAC-SMA) rainfall-runoff model to produce daily river and flood forecasts and issue flood warnings. The manual observations of total sky cover used to estimate solar radiation and potential evapotranspir...

  3. Listing of solar radiation measuring equipment and glossary

    NASA Technical Reports Server (NTRS)

    Carter, E. A.; Greenbaum, S. A.; Patel, A. M.

    1976-01-01

    An attempt is made to list and provide all available information about solar radiation measuring equipment which are being manufactured and are available on the market. The list is in tabular form and includes sensor type, response time, cost data and comments for each model. A cost code is included which shows ranges only.

  4. Solar Irradiance: Observations, Proxies, and Models (Invited)

    NASA Astrophysics Data System (ADS)

    Lean, J.

    2013-12-01

    Solar irradiance has been measured from space for more than thirty years. Variations in total (spectrally integrated) solar irradiance associated with the Sun's 11-year activity cycle and 27-day rotation are now well characterized. But the magnitude, and even the sign, of spectral irradiance changes at near ultraviolet, visible and near infrared wavelengths, remain uncertain on time scales longer than a few months. Drifts in the calibration of the instruments that measure solar irradiance and incomplete understanding of the causes of irradiance variations preclude specification of multi-decadal solar irradiance variations with any confidence, including whether, or not, irradiance levels were lower during the 2008-2009 anomalously low solar activity minimum than in prior minima. The ultimate cause of solar irradiance variations is the Sun's changing activity, driven by a sub-surface dynamo that generates magnetic features called sunspots and faculae, which respectively deplete and enhance the net radiative output. Solar activity also alters parameters that have been measured from the ground for longer periods and with greater stability than the solar irradiance datasets. The longest and most stable such record is the Sun's irradiance at 10.7 cm in the radio spectrum, which is used frequently as a proxy indicator of solar irradiance variability. Models have been developed that relate the solar irradiance changes - both total and spectral - evident in extant databases to proxies chosen to best represent the sunspot darkening and facular brightening influences. The proxy models are then used to reconstruct solar irradiance variations at all wavelengths on multi-decadal time scales, for input to climate and atmospheric model simulations that seek to quantity the Sun's contribution to Earth's changing environment. This talk provides an overview of solar total and spectral irradiance observations and their relevant proxies, describes the formulation and construction of

  5. A statistical model for the selection of ground observations of solar radiation: an application in producing a five-year dataset of radiation maps on Italian territory through correction of MSG-derived data

    NASA Astrophysics Data System (ADS)

    Campo, Lorenzo; Castelli, Fabio

    2011-11-01

    The incident solar radiation is one of the component of the land surface energy budget and constitutes an essential input for several applications. An accurate estimation of this variable on large areas requires a dense network of ground sensors and continuous knowledge of the cloud cover, that are rarely available. A valid alternative in this respect is constituted by the remote sensing. In this work a simple algorithm is used in order to integrate the LSA-SAF (Land Surface Analysis Satellite Applications Facility) products of shortwave incident radiation obtained from MSG-SEVIRI imagery with ground radiometers observations. A statistical approach is followed in order to define a criterion for accept or reject the ground sensors observations, by modelling the mean daily error between the observations and a theoretical radiation time series and the cloud cover observations with probability distribution functions. Such distributions is used for the ground sensors selection criterion. The analysis is used to produce a dataset of corrected solar radiation maps on the whole Italian territory for a period of 5 years (2005-2009).

  6. Analysis of the ozone profile specifications in the WRF-ARW model and their impact on the simulation of direct solar radiation

    NASA Astrophysics Data System (ADS)

    Montornès, A.; Codina, B.; Zack, J. W.

    2015-03-01

    Although ozone is an atmospheric gas with high spatial and temporal variability, mesoscale numerical weather prediction (NWP) models simplify the specification of ozone concentrations used in their shortwave schemes by using a few ozone profiles. In this paper, a two-part study is presented: (i) an evaluation of the quality of the ozone profiles provided for use with the shortwave schemes in the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) model and (ii) an assessment of the impact of deficiencies in those profiles on the performance of model simulations of direct solar radiation. The first part compares simplified data sets used to specify the total ozone column in six schemes (i.e., Goddard, New Goddard, RRTMG, CAM, GFDL and Fu-Liou-Gu) with the Multi-Sensor Reanalysis data set during the period 1979-2008 examining the latitudinal, longitudinal and seasonal limitations in the ozone profile specifications of each parameterization. The results indicate that the maximum deviations are over the poles and show prominent longitudinal patterns in the departures due to the lack of representation of the patterns associated with the Brewer-Dobson circulation and the quasi-stationary features forced by the land-sea distribution, respectively. In the second part, the bias in the simulated direct solar radiation due to these deviations from the simplified spatial and temporal representation of the ozone distribution is analyzed for the New Goddard and CAM schemes using the Beer-Lambert-Bouguer law and for the GFDL using empirical equations. For radiative applications those simplifications introduce spatial and temporal biases with near-zero departures over the tropics throughout the year and increasing poleward with a maximum in the high middle latitudes during the winter of each hemisphere.

  7. On the ability of RegCM4 regional climate model to simulate surface solar radiation patterns over Europe: an assessment using satellite-based observations

    NASA Astrophysics Data System (ADS)

    Alexandri, G.; Georgoulias, A. K.; Zanis, P.; Katragkou, E.; Tsikerdekis, A.; Kourtidis, K.; Meleti, C.

    2015-07-01

    In this work, we assess the ability of RegCM4 regional climate model to simulate surface solar radiation (SSR) patterns over Europe. A decadal RegCM4 run (2000-2009) was implemented and evaluated against satellite-based observations from the Satellite Application Facility on Climate Monitoring (CM SAF) showing that the model simulates adequately the SSR patterns over the region. The bias between RegCM4 and CM SAF is +1.54 % for MFG (Meteosat First Generation) and +3.34 % for MSG (Meteosat Second Generation) observations. The relative contribution of parameters that determine the transmission of solar radiation within the atmosphere to the deviation appearing between RegCM4 and CM SAF SSR is also examined. Cloud macrophysical and microphysical properties such as cloud fractional cover (CFC), cloud optical thickness (COT) and cloud effective radius (Re) from RegCM4 are evaluated against data from CM SAF. The same procedure is repeated for aerosol optical properties such as aerosol optical depth (AOD), asymmetry factor (ASY) and single scattering albedo (SSA), as well as other parameters including surface broadband albedo (ALB) and water vapor amount (WV) using data from MACv1 aerosol climatology, from CERES satellite sensors and from ERA-Interim reanalysis. It is shown here that the good agreement between RegCM4 and satellite-based SSR observations can be partially attributed to counteracting effects among the above mentioned parameters. The contribution of each parameter to the RegCM4-CM SAF SSR deviations is estimated with the combined use of the aforementioned data and a radiative transfer model (SBDART). CFC, COT and AOD are the major determinants of these deviations; however, the other parameters also play an important role for specific regions and seasons.

  8. Medically important solar ultraviolet A. Radiation measurements.

    PubMed

    Ilyas, M; Abdul Aziz, D; Tajuddin, M R

    1988-06-01

    Results from a 6-year study of solar ultraviolet A (UVA) radiation measurements at the equatorial location of Penang (5 degrees N) are presented. On clear days, the diurnal flux reaches a very high dosage of about 3.0 x 10(-2) KWHM-2 around midday. The average daily total flux is in the range of 1.6 x 10(-1) KWHM-2 and does not change much seasonally. The high 83% cloud cover only reduces the incoming flux to about half. The radiation flux represents a lower limit of the incident UVA radiation applicable to much of the equatorial/tropical region. PMID:3391727

  9. Radiation balances and the solar constant

    NASA Technical Reports Server (NTRS)

    Crommelynck, D.

    1981-01-01

    The radiometric concepts are defined in order to consider various types of radiation balances and relate them to the diabetic form of the energy balance. Variability in space and time of the components of the radiation field are presented. A specific concept for sweeping which is tailored to the requirements is proposed. Finally, after establishing the truncated character of the present knowledge of the radiation balance. The results of the last observations of the solar constant are given. Ground and satellite measurement techniques are discussed.

  10. Radiation balances and the solar constant

    NASA Astrophysics Data System (ADS)

    Crommelynck, D.

    1981-07-01

    The radiometric concepts are defined in order to consider various types of radiation balances and relate them to the diabetic form of the energy balance. Variability in space and time of the components of the radiation field are presented. A specific concept for sweeping which is tailored to the requirements is proposed. Finally, after establishing the truncated character of the present knowledge of the radiation balance. The results of the last observations of the solar constant are given. Ground and satellite measurement techniques are discussed.