WorldWideScience

Sample records for monthly-average global radiation

  1. Monthly average daily global solar radiation in P. D. R. Yemen

    Energy Technology Data Exchange (ETDEWEB)

    Gadhi, S.M.B.; Megdad, R.S.; Albakri, S.A.A. (Aden Univ. (Yemen). Dept. of Mechanical Engineering)

    1991-01-01

    In this paper a study has been made to estimate average global radiation using hours of bright sunshine and measured solar radiation data available for six locations in P.D.R. Yemen. For Aden, data were obtained from Aden Airport. For other locations in P.D.R. Yemen data were obtained from Agricultural Research Center's meteorological sections. Linear regression analysis of the monthly average global radiation and the sunshine duration data of six locations has been performed using the least squares technique. All the above mentioned data have been used in Angstrom's correlation to find the monthly average daily global solar radiation. Results obtained are useful for any solar energy system application in P.D.R. Yemen. (author).

  2. Estimation of the diffuse radiation fraction for hourly, daily and monthly-average global radiation

    Science.gov (United States)

    Erbs, D. G.; Klein, S. A.; Duffie, J. A.

    1982-01-01

    Hourly pyrheliometer and pyranometer data from four U.S. locations are used to establish a relationship between the hourly diffuse fraction and the hourly clearness index. This relationship is compared to the relationship established by Orgill and Hollands (1977) and to a set of data from Highett, Australia, and agreement is within a few percent in both cases. The transient simulation program TRNSYS is used to calculate the annual performance of solar energy systems using several correlations. For the systems investigated, the effect of simulating the random distribution of the hourly diffuse fraction is negligible. A seasonally dependent daily diffuse correlation is developed from the data, and this daily relationship is used to derive a correlation for the monthly-average diffuse fraction.

  3. Insolation data manual: long-term monthly averages of solar radiation, temperature, degree-days and global anti K/sub T/ for 248 national weather service stations

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, C L; Stoffel, T L; Whitaker, S D

    1980-10-01

    Monthly averaged data is presented which describes the availability of solar radiation at 248 National Weather Service stations. Monthly and annual average daily insolation and temperature values have been computed from a base of 24 to 25 years of data. Average daily maximum, minimum, and monthly temperatures are provided for most locations in both Celsius and Fahrenheit. Heating and cooling degree-days were computed relative to a base of 18.3/sup 0/C (65/sup 0/F). For each station, global anti K/sub T/ (cloudiness index) were calculated on a monthly and annual basis. (MHR)

  4. Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean based on AERONET aerosol properties

    Directory of Open Access Journals (Sweden)

    A. Bergamo

    2008-12-01

    Full Text Available The all-sky direct radiative effect by anthropogenic aerosol (DREa is calculated in the solar (0.3–4 μm and infrared (4–200 μm spectral ranges for six Mediterranean sites. The sites are differently affected by pollution and together reflect typical aerosol impacts that are expected over land and coastal sites of the central Mediterranean basin. Central to the simulations are aerosol optical properties from AERONET sun-/sky-photometer statistics for the year 2003. A discussion on the variability of the overall (natural + anthropogenic aerosol properties with site location is provided. Supplementary data include MODIS satellite sensor based solar surface albedos, ISCCP products for high- mid- and low cloud cover and estimates for the anthropogenic aerosol fraction from global aerosol models. Since anthropogenic aerosol particles are considered to be smaller than 1 μm in size, mainly the solar radiation transfer is affected with impacts only during sun-light hours. At all sites the (daily average solar DREa is negative all year round at the top of the atmosphere (ToA. Hence, anthropogenic particles produce over coastal and land sites of the central Mediterranean a significant cooling effect. Monthly DREa values vary from site to site and are seasonally dependent as a consequence of the seasonal dependence of available sun-light and microphysical aerosol properties. At the ToA the monthly average DREa is −(4±1 W m−2 during spring-summer (SS, April–September and −(2±1 W m−2 during autumn-winter (AW, October–March at the polluted sites. In contrast, it varies between −(3±1 W m−2 and −(1±1 W m−2 on SS and AW, respectively at the less polluted site. Due to atmospheric absorption the DREa at the surface is larger than at the ToA. At the surface the monthly average DREa varies between the most and the least polluted

  5. Estimation of monthly average daily global solar irradiation using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Mubiru, J.; Banda, E.J.K.B. [Department of Physics, Makerere University, P.O. Box 7062, Kampala (Uganda)

    2008-02-15

    This study explores the possibility of developing a prediction model using artificial neural networks (ANN), which could be used to estimate monthly average daily global solar irradiation on a horizontal surface for locations in Uganda based on weather station data: sunshine duration, maximum temperature, cloud cover and location parameters: latitude, longitude, altitude. Results have shown good agreement between the estimated and measured values of global solar irradiation. A correlation coefficient of 0.974 was obtained with mean bias error of 0.059 MJ/m{sup 2} and root mean square error of 0.385 MJ/m{sup 2}. The comparison between the ANN and empirical method emphasized the superiority of the proposed ANN prediction model. (author)

  6. Statistical comparison of models for estimating the monthly average daily diffuse radiation at a subtropical African site

    Energy Technology Data Exchange (ETDEWEB)

    Bashahu, M. [University of Burundi, Bujumbura (Burundi). Institute of Applied Pedagogy, Department of Physics and Technology

    2003-07-01

    Nine correlations have been developed in this paper to estimate the monthly average diffuse radiation for Dakar, Senegal. A 16-year period data on the global (H) and diffuse (H{sub d}) radiation, together with data on the bright sunshine hours (N), the fraction of the sky's (Ne/8), the water vapour pressure in the air (e) and the ambient temperature (T) have been used for that purpose. A model inter-comparison based on the MBE, RMSE and t statistical tests has shown that estimates in any of the obtained correlations are not significantly different from their measured counterparts, thus all the nine models are recommended for the aforesaid location. Three of them should be particularly selected for their simplicity, universal applicability and high accuracy. Those are simple linear correlations between K{sub d} and N/N{sub d}, Ne/8 or K{sub t}. Even presenting adequate performance, the remaining correlations are either simple but less accurate, or multiple or nonlinear regressions needing one or two input variables. (author)

  7. Assessing monthly average solar radiation models: a comparative case study in Turkey.

    Science.gov (United States)

    Sonmete, Mehmet H; Ertekin, Can; Menges, Hakan O; Hacıseferoğullari, Haydar; Evrendilek, Fatih

    2011-04-01

    Solar radiation data are required by solar engineers, architects, agriculturists, and hydrologists for many applications such as solar heating, cooking, drying, and interior illumination of buildings. In order to achieve this, numerous empirical models have been developed all over the world to predict solar radiation. The main objective of this study is to examine and compare 147 solar radiation models available in the literature for the prediction of monthly solar radiation at Ankara (Turkey) based on selected statistical measures such as percentage error, mean percentage error, root mean square error, mean bias error, and correlation coefficient. Our results showed that Ball et al. (Agron J 96:391-397, 2004) model and Chen et al. (Energy Convers Manag 47:2859-2866, 2006) model performed best in the estimation of solar radiation on a horizontal surface for Ankara.

  8. Estimation of the monthly average daily solar radiation using geographic information system and advanced case-based reasoning.

    Science.gov (United States)

    Koo, Choongwan; Hong, Taehoon; Lee, Minhyun; Park, Hyo Seon

    2013-05-07

    The photovoltaic (PV) system is considered an unlimited source of clean energy, whose amount of electricity generation changes according to the monthly average daily solar radiation (MADSR). It is revealed that the MADSR distribution in South Korea has very diverse patterns due to the country's climatic and geographical characteristics. This study aimed to develop a MADSR estimation model for the location without the measured MADSR data, using an advanced case based reasoning (CBR) model, which is a hybrid methodology combining CBR with artificial neural network, multiregression analysis, and genetic algorithm. The average prediction accuracy of the advanced CBR model was very high at 95.69%, and the standard deviation of the prediction accuracy was 3.67%, showing a significant improvement in prediction accuracy and consistency. A case study was conducted to verify the proposed model. The proposed model could be useful for owner or construction manager in charge of determining whether or not to introduce the PV system and where to install it. Also, it would benefit contractors in a competitive bidding process to accurately estimate the electricity generation of the PV system in advance and to conduct an economic and environmental feasibility study from the life cycle perspective.

  9. A preliminary study of the linear relationship between monthly averaged daily solar radiation and daily thermal amplitude in the north of Buenos Aires provence

    CERN Document Server

    Cionco, R; Rodriguez, R

    2012-01-01

    Using irradiance and temperature measurements obtained at the Facultad Regional San Nicol\\'as of UTN, we performed a preliminary study of the linear relationship between monthly averaged daily solar radiation and daily thermal amplitude. The results show a very satisfactory adjustment (R = 0.848, RMS = 0.066, RMS% = 9.690 %), even taking into account the limited number of months (36). Thus, we have a formula of predictive nature, capable of estimating mean monthly solar radiation for various applications. We expect to have new data sets to expand and improve the statistical significance of these results.

  10. Global solar irradiation in Italy during 1994 : monthly average daily values for 1614 sites estimated from Meteosat images; Radiazione solare globale al suolo in Italia nel 1994 : valori medi mensili per 1.614 localita` italiane stimate a partire dalle immagini fornite dal satellite Meteosat

    Energy Technology Data Exchange (ETDEWEB)

    Cogliani, E.; Mancini, M.; Petrarca, S.; Spinelli, F. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dip. Energia

    1995-10-01

    The global solar radiation over Italy is estimated from Meteosat secondary images in the visible band. The stimation method relies on the fact that the cloud cover on a given area of the Earth`s surface statistically determines the amount of solar radiation falling on that area. Estimated values of the monthly average daily global radiation on a horizontal surface for the 1994 have been compared with values computed from data measured by the stations of the two Italian radiation networks: the Meteorological Service of the Italian Air Force and the National Agrometeorological Network (a total of 36 stations have been considered). The mean percentage difference between estimated and computed values over the year is 6 per cent. In the present report, the monthly maps of radiation over Italy and the estimated monthly average daily values for over 1600 sites (having more than 10,000 inhabitants) are given. In the yearly reports to be issued in the years to come, maps and mean values over the period starting with 1994 will be given as well.

  11. Global solar radiation climate of Libya

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, S.; Abuain, Taher (Al-Fateh Univ., Tripoli (LY). Dept. of Physics)

    1992-02-01

    This paper presents the general features of the global solar radiation measured by 15 meteorological stations spread over Libya during the 5-yr period, 1981-1986. A number of methods for correlating monthly average daily global radiation with recorded sunshine duration have been attempted. It is found that some well known correlation formulae show large discrepancies in predicting the global radiation of Libya. However, the Dogniaux-Lemoine correlation equation is found to be suitable for the prediction, particularly in the coastal regions. The present analysis indicates that solar radiation in the Libyan climate can be classified into two broad divisions, coastal and desert, with two sub-divisions in each of the divisions. Station-independent correlation parameters for these regions are calculated. (Author).

  12. Construction of a Quadratic Model for Predicted and Measured Global Solar Radiation in Chile

    Institute of Scientific and Technical Information of China (English)

    Ercan YILMAZ; Beatriz CANCINO; Edmundo LOPEZ

    2007-01-01

    @@ Global solar radiation data for sites in Chile are analysed and presented in a form suitable for their use in engineering. A new model for monthly average data is developed to predict monthly average global radiation with acceptable accuracy by using actinographic data due to scarcing of pyranometer data. Use of the new quadratic model is proposed because of its relatively wider spectrum of values for (A)ngstrom coefficients a0, a1,and a2.

  13. Model selection for global and diffuse radiation over the Central Black Sea (CBS) region of Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Tarhan, Sefa [Gaziosmanpasa Univ., Dept. of Farm Machinery, Tokat (Turkey); Sari, Ahmet [Gaziosmanpasa Univ., Dept. of Chemistry, Tokat (Turkey)

    2005-03-01

    Solar radiation over the Central Black Sea Region of Turkey, covering the five provinces (Amasya, Corum, Ordu, Samsun and Tokat), was analyzed to guide future projects. The maximum monthly average global solar radiation ranged from 20.05 (for Ordu) to 23.71 MJ m{sup -2} (for Tokat). The maximum monthly average daily measured sunshine duration ranged from 6.89 (for Ordu) to 11 h (for Corum). A quadratic polynomial equation was empirically developed to predict the monthly average daily global radiation. A hybrid model was also developed based on the predictions of six existing models to predict the monthly average daily diffuse and beam radiation. Various statistical tests (analysis of variance for model adequacy and t-test for significance of model parameter etc.) have shown that the models developed in this study are adequate for solar radiation prediction. (Author)

  14. Model for forecasting of monthly average insulation at ground level taking into account the radiation absorption losses crossing atmosphere in the thermal solar applications; Modelo de previsao da insolacao media mensal ao nivel do solo levando em conta a perda por absorcao na atmosfera em aplicacoes solares termicas

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, J.C.; Apolinario, F.R.; Silva, E.P. da [Universidade Estadual de Campinas, SP (Brazil). Lab. de Hidrogenio]. E-mails: joaoc@fem.unicamp.br; rezende@ifi.unicamp.br; lh2ennio@ifi.unicamp.br

    2000-07-01

    The use of the solar energy, for thermal or photovoltaic ends, depends basically on the amount of radiation that reaches the ground in the place where desires to carry through this use, defining the necessary area of the collectors, or panels, that in turn are the main components of the final cost of the system and, therefore, of the viability or not on its use. The incident radiation in the terrestrial surface is minor that one reaches the top of the atmosphere due to the absorption and dispersion factors. The objective of this work is to present a model of forecast the monthly average radiation for ends of use in systems of flat solar collectors for heating water, in the city of Campinas - Sao Paulo, Brazil. This work has been developed by the Hydrogen Laboratory of the Institute of Physics of the UNICAMP, being also used for other applications with solar energy. Based in the radiation data, taken from a local station, a theoretical study was developed to calculate a parameter of loss of radiation when this cross the atmosphere. This Kt loss factor, has basic importance for the knowledge of the effective available energy for use. With this data it is possible to determine, on the basis of the incident radiation in the top of the atmosphere, the value of the radiation on a surface. (author)

  15. Ocean tides in GRACE monthly averaged gravity fields

    DEFF Research Database (Denmark)

    Knudsen, Per

    2003-01-01

    aims at. In this analysis the results of Knudsen and Andersen (2002) have been verified using actual post-launch orbit parameter of the GRACE mission. The current ocean tide models are not accurate enough to correct GRACE data at harmonic degrees lower than 47. The accumulated tidal errors may affect......The GRACE mission will map the Earth's gravity fields and its variations with unprecedented accuracy during its 5-year lifetime. Unless ocean tide signals and their load upon the solid earth are removed from the GRACE data, their long period aliases obscure more subtle climate signals which GRACE...... the GRACE data up to harmonic degree 60. A study of the revised alias frequencies confirm that the ocean tide errors will not cancel in the GRACE monthly averaged temporal gravity fields. The S-2 and the K-2 terms have alias frequencies much longer than 30 days, so they remain almost unreduced...

  16. Global Health in Radiation Oncology

    DEFF Research Database (Denmark)

    Rodin, Danielle; Yap, Mei Ling; Grover, Surbhi

    2017-01-01

    The massive global shortfall in radiotherapy equipment and human resources in developing countries is an enormous challenge for international efforts in cancer control. This lack of access to treatment has been long-standing, but there is now a growing consensus about the urgent need to prioritize...... programs. However, formalized training and career promotion tracks in global health within radiation oncology have been slow to emerge, thereby limiting the sustained involvement of students and faculty, and restricting opportunities for leadership in this space. We examine here potential structures...... and funding models might be used to further develop and expand radiation oncology services globally....

  17. Global radiation on inclined surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Aydinli, S.; Rattunde, R.; Krochmann, J.

    1981-02-01

    Radiation intensities and irradiances resulting from global radiation incident on inclined surfaces are important for solar energy use in heating and air conditioning of buildings. Both quantities are a function of astronomical, meteorological, and other parameters of the insolation geometry. Methods of calculation for cloudy, clear, and partly cloudy skies are described which may be carried out with the aid of programmable desk computers. Computer programs have been specially developed for this purpose. Their results are compared with other theoretical data and with data of the Hamburg Meteorological Observatory. Simplified results obtained with the aid of tables are found to be inaccurate while the computer programs provide satisfactory results.

  18. Evaluation of global solar radiation using multiple weather parameters as predictors for South Africa provinces

    Directory of Open Access Journals (Sweden)

    Adeala Adeyemi A.

    2015-01-01

    Full Text Available Models for estimating monthly average daily global solar radiation were developed for South African provinces. These models, in addition to the traditional sunshine hours used in existing models incorporates ambient temperature, relative humidity and wind speed as variable parameters for predicting global solar radiation, making it different from most of the existing models that use only sunshine hours as variable. Meteorological data obtained for nine locations in South Africa were employed in the model formulation. The accuracy of the models were verified by comparing estimated values with measured values in terms of the following statistical error tests: mean bias error (MBE, mean absolute bias error (MABE, mean absolute percentage error (MAPE, root mean square error (RMSE, and the regression coefficient (R2.The values of R2 for the formulated models are between the ranges of 90% - 99%. It was also observed that for an accurate estimation of global solar radiation in Eastern Cape Province, all weather elements are needed. This implies that the models give an excellent prediction for global solar radiation for their corresponding locations. Also, different errors calculated for the formulated models are close to zero especially MAPE. The result shows that the formulated models are good enough to be used to predict monthly average daily radiation for South Africa and also, the inclusion of some other elements in some of the models improved the accuracy of the predictions made by the models.

  19. Using of rank distributions in the study of perennial changes for monthly average temperatures

    Science.gov (United States)

    Nemirovskiy, V. B.; Stoyanov, A. K.; Tartakovsky, V. A.

    2015-11-01

    The possibility of comparing the climatic data of various years with using rank distributions is considered in this paper. As a climatic data, the annual variation of temperature on the spatial areas of meteorological observations with high variability in average temperatures is considered. The results of clustering of the monthly average temperatures values by means of a recurrent neural network were used as the basis of comparing. For a given space of weather observations the rank distribution of the clusters cardinality identified for each year of observation, is being constructed. The resulting rank distributions allow you to compare the spatial temperature distributions of various years. An experimental comparison for rank distributions of the annual variation of monthly average temperatures has confirmed the presence of scatter for various years, associated with different spatio-temporal distribution of temperature. An experimental comparison of rank distributions revealed a difference in the integral annual variation of monthly average temperatures of various years for the Northern Hemisphere.

  20. Estimación de la radiación solar global incidente en superficies inclinadas (ING)

    National Research Council Canada - National Science Library

    Jaime Wright

    2016-01-01

    Monthly averages of daily global radiation incident upon a tilted southfacing surface were computed from the available values of global, direct or diffuse solar radiation incident upon a horizontal surface...

  1. Developing a Mathematical Model to Estimate the Intensity of the Global Radiation

    Directory of Open Access Journals (Sweden)

    Poramate CHUNPANG

    2016-04-01

    Full Text Available This research aimed to create an empirical mathematical model to estimate the average monthly of total daily radiation of the global radiation in the middle of northeast Thailand. The model showed the ratio of the monthly average of daily radiation on the radiation outside the Earth's atmosphere which contains cloud index: n, ozone: l, perceptible water: w, and visibility: VIS, where: the value of n came from the data from meteorological satellites MTSAT-2, the value of l came from the data from AURA satellite, the value of w was calculated from temperature and humidity of the air, and the value of VIS came from the measurements from meteorological stations. For testing the performance of the model, the researchers calculated the average monthly of total daily radiation intensity at Maha Sarakham, Roi Et, Khon Kaen and Kalasin provincial meteorological stations. Then, the results were compared with the measured values. The comparison showed that the results from the calculation and measurement are consistent in the good standing. The Root Mean Square Difference value (RMSD of the monthly average of total daily radiation intensity was between 5.25 to 13.82%. On the other hand, the Mean Bias Difference value (MBD was negative within the range of -0.99 to -13.47%.

  2. Analysis of diffuse radiation data for Beer Sheva: Measured (shadow ring) versus calculated (global-horizontal beam) values

    Energy Technology Data Exchange (ETDEWEB)

    Kudish, A.I. (Ben-Gurion Univ. of the Negev, Beer Sheva (Israel)); Ianetz, A. (Israel Meteorological Service, Bet Dagan (Israel))

    1993-12-01

    The authors have utilized concurrently measured global, normal incidence beam, and diffuse radiation data, the latter measured by means of a shadow ring pyranometer to study the relative magnitude of the anisotropic contribution (circumsolar region and nonuniform sky conditions) to the diffuse radiation. In the case of Beer Sheva, the monthly average hourly anisotropic correction factor varies from 2.9 to 20.9%, whereas the [open quotes]standard[close quotes] geometric correction factor varies from 5.6 to 14.0%. The monthly average hourly overall correction factor (combined anisotropic and geometric factors) varies from 8.9 to 37.7%. The data have also been analyzed using a simple model of sky radiance developed by Steven in 1984. His anisotropic correction factor is a function of the relative strength and angular width of the circumsolar radiation region. The results of this analysis are in agreement with those previously reported for Quidron on the Dead Sea, viz. the anisotropy and relative strength of the circumsolar radiation are significantly greater than at any of the sites analyzed by Steven. In addition, the data have been utilized to validate a model developed by LeBaron et al. in 1990 for correcting shadow ring diffuse radiation data. The monthly average deviation between the corrected and true diffuse radiation values varies from 4.55 to 7.92%.

  3. GEWEX Surface Radiation Budget (SRB)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NASA/GEWEX Surface Radiation Budget (SRB) Release-3.0 data sets contains global 3-hourly, daily, monthly/3-hourly, and monthly averages of surface and top-of...

  4. A new methodology for generating hourly exposure sequences of global radiation for its use in solar simulation programs

    Energy Technology Data Exchange (ETDEWEB)

    Mora Lopez, Ll. [Dept. Lenguajes y Ciencias de la Computacion, E.T.S.I., Univ. de Malaga (Spain); Sidrach de Cardona, M. [Dept. Fisica Aplicada, E.T.S.I., Univ. de Malaga (Spain)

    1996-12-31

    For the sizing, design and simulation of solar energy system with memory (storage capacity) from one to a few hours it is recommended to use hourly exposure series of global radiation. These values allow us to know the way these systems work with greater precision. Specifically, when the optimal sizing of these systems wants to be achieved from an energetic economic point of view, it is fundamental to make a precise system design. However, in many locations this kind of data are not available, and only monthly average values of daily global radiation - or, sometimes, daily exposure series of global radiation - are know. In this work, the theory of stochastic processes is used to analyse the main characteristics of hourly exposure series of global radiation. The objective which is pursued is to analyze whether these series can be identified with a statistical model and check if this statistical model and its parameters can be applied to the various series which are analysed. (orig.)

  5. The monthly-averaged and yearly-averaged cosine effect factor of a heliostat field

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rabghi, O.M.; Elsayed, M.M. (King Abdulaziz Univ., Jeddah (Saudi Arabia). Dept. of Thermal Engineering)

    1992-01-01

    Calculations are carried out to determine the dependence of the monthly-averaged and the yearly-averaged daily cosine effect factor on the pertinent parameters. The results are plotted on charts for each month and for the full year. These results cover latitude angles between 0 and 45[sup o]N, for fields with radii up to 50 tower height. In addition, the results are expressed in mathematical correlations to facilitate using them in computer applications. A procedure is outlined to use the present results to preliminary layout the heliostat field, and to predict the rated MW[sub th] reflected by the heliostat field during a period of a month, several months, or a year. (author)

  6. The impact of orbital sampling, monthly averaging and vertical resolution on climate chemistry model evaluation with satellite observations

    Directory of Open Access Journals (Sweden)

    A. M. Aghedo

    2011-07-01

    Full Text Available Ensemble climate model simulations used for the Intergovernmental Panel on Climate Change (IPCC assessments have become important tools for exploring the response of the Earth System to changes in anthropogenic and natural forcings. The systematic evaluation of these models through global satellite observations is a critical step in assessing the uncertainty of climate change projections. This paper presents the technical steps required for using nadir sun-synchronous infrared satellite observations for multi-model evaluation and the uncertainties associated with each step. This is motivated by need to use satellite observations to evaluate climate models. We quantified the implications of the effect of satellite orbit and spatial coverage, the effect of variations in vertical sensitivity as quantified by the observation operator and the impact of averaging the operators for use with monthly-mean model output. We calculated these biases in ozone, carbon monoxide, atmospheric temperature and water vapour by using the output from two global chemistry climate models (ECHAM5-MOZ and GISS-PUCCINI and the observations from the Tropospheric Emission Spectrometer (TES instrument on board the NASA-Aura satellite from January 2005 to December 2008.

    The results show that sampling and monthly averaging of the observation operators produce zonal-mean biases of less than ±3 % for ozone and carbon monoxide throughout the entire troposphere in both models. Water vapour sampling zonal-mean biases were also within the insignificant range of ±3 % (that is ±0.14 g kg−1 in both models. Sampling led to a temperature zonal-mean bias of ±0.3 K over the tropical and mid-latitudes in both models, and up to −1.4 K over the boundary layer in the higher latitudes. Using the monthly average of temperature and water vapour operators lead to large biases over the boundary layer in the southern-hemispheric higher latitudes and in the upper

  7. The impact of orbital sampling, monthly averaging and vertical resolution on climate chemistry model evaluation with satellite observations

    Directory of Open Access Journals (Sweden)

    A. M. Aghedo

    2011-03-01

    Full Text Available Ensemble climate model simulations used for the Intergovernmental Panel on Climate Change (IPCC assessments have become important tools for exploring the response of the Earth System to changes in anthropogenic and natural forcings. The systematic evaluation of these models through global satellite observations is a critical step in assessing the uncertainty of climate change projections. This paper presents the technical steps required for using nadir sun-synchronous infrared satellite observations for multi-model evaluation and the uncertainties associated with each step. This is motivated by need to use satellite observations to evaluate climate models. We quantified the implications of the effect of satellite orbit and spatial coverage, the effect of variations in vertical sensitivity as quantified by the observation operator and the impact of averaging the operators for use with monthly-mean model output. We calculated these biases in ozone, carbon monoxide, atmospheric temperature and water vapour by using the output from two global chemistry climate models (ECHAM5-MOZ and GISS-PUCCINI and the observations from the Tropospheric Emission Spectrometer (TES satellite from January 2005 to December 2008.

    The results show that sampling and monthly averaging of the observation operators produce biases of less than ±3% for ozone and carbon monoxide throughout the entire troposphere in both models. Water vapour sampling biases were also within the insignificant range of ±3% (that is ±0.14 g kg−1 in both models. Sampling led to a temperature bias of ±0.3 K over the tropical and mid-latitudes in both models, and up to −1.4 K over the boundary layer in the higher latitudes. Using the monthly average of temperature and water vapour operators lead to large biases over the boundary layer in the southern-hemispheric higher latitudes and in the upper troposphere, respectively. Up to 8% bias was calculated in the upper

  8. Cloud effects on middle ultraviolet global radiation

    Science.gov (United States)

    Borkowski, J.; Chai, A.-T.; Mo, T.; Green, A. E. O.

    1977-01-01

    An Eppley radiometer and a Robertson-Berger sunburn meter are employed along with an all-sky camera setup to study cloud effects on middle ultraviolet global radiation at the ground level. Semiempirical equations to allow for cloud effects presented in previous work are compared with the experimental data. The study suggests a means of defining eigenvectors of cloud patterns and correlating them with the radiation at the ground level.

  9. A Linear Regression Model for Global Solar Radiation on Horizontal Surfaces at Warri, Nigeria

    Directory of Open Access Journals (Sweden)

    Michael S. Okundamiya

    2013-10-01

    Full Text Available The growing anxiety on the negative effects of fossil fuels on the environment and the global emission reduction targets call for a more extensive use of renewable energy alternatives. Efficient solar energy utilization is an essential solution to the high atmospheric pollution caused by fossil fuel combustion. Global solar radiation (GSR data, which are useful for the design and evaluation of solar energy conversion system, are not measured at the forty-five meteorological stations in Nigeria. The dearth of the measured solar radiation data calls for accurate estimation. This study proposed a temperature-based linear regression, for predicting the monthly average daily GSR on horizontal surfaces, at Warri (latitude 5.020N and longitude 7.880E an oil city located in the south-south geopolitical zone, in Nigeria. The proposed model is analyzed based on five statistical indicators (coefficient of correlation, coefficient of determination, mean bias error, root mean square error, and t-statistic, and compared with the existing sunshine-based model for the same study. The results indicate that the proposed temperature-based linear regression model could replace the existing sunshine-based model for generating global solar radiation data. Keywords: air temperature; empirical model; global solar radiation; regression analysis; renewable energy; Warri

  10. Analysis of daily clearness index, global and beam radiation for Beer Sheva, Israel: partition according to day type and statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kudish, A.I. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Chemical Engineering; Ianetz, A. [Israel Meteorological Service, Bet Dagan (Israel). Research and Development Div.

    1996-04-01

    The magnitude of the daily clearness index K{sub T} has been utilized to classify a day as either clear, partially cloudy or cloudy. The range of values for defining a day type was based upon a previous analysis of the Beer Sheva radiation database. These criteria were employed to partition the days according to type and the corresponding monthly average daily values for the clearness index, global, normal incidence and horizontal beam radiation were calculated. A statistical analysis was performed on each of the monthly average daily value subsets to help convey the shape of their respective distribution curves. The monthly average frequency of days according to type was also determined. Such an analysis of the solar radiation database for a particular site can be utilized to determine the relative merits of different types of solar energy conversion systems, e.g. concentrating vis-avis non-concentrating solar collector systems. The results of this analysis for Beer Sheva indicate that this region is very amenable to the utilization of non-concentrating solar energy conversion systems, since the combined frequency of both clear and partially cloudy days exceeds 80% annually. In addition, the Beer Sheva region is a prime candidate for the use of solar energy conversion systems utilizing concentrating collectors due to its relatively high frequency of clear day and the fact that the monthly average daily vales of the clearness index. (Author)

  11. An overview of global solar radiation measurements in Ghardaia area, south Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Gairaa, Kacem; Bakelli, Yahia [Applied Research Unit for Renewables Energies, Ouargla Road, Ghardaia (Algeria)

    2011-07-01

    This paper presents an overview of actual solar radiation data measurements in Ghardaia site (32.360 N, 3.810 W, 450 m above MSL). Global solar radiation and surface temperatures were measured and analyzed for one complete year from 1 January-31December 2005. The data thus recorded are compared with corresponding data of the 22-year average of NASA's surface meteorology and solar energy-model. Hourly, daily and monthly solar radiation was made from five-minute recorded by EKO Pyranometer. The highest measured daily and monthly mean solar radiation was found to be 369 and 326 (W/m2), and the highest five minute averaged solar radiation values up to 1268 (W/m2) were observed in the summer season from May to September, and the yearly average daily energy input was 21.83 (MJ/m2/day). Besides the global solar radiation, the daily and monthly average temperature variations are discussed. The collected data indicate that Ghardaia has a strong potential for solar energy applications.

  12. An overview of global solar radiation measurements in Ghardaia area, south Algeria

    Directory of Open Access Journals (Sweden)

    Kacem Gairaa, Yahia Bakelli

    2011-03-01

    Full Text Available This paper presents an overview of actual solar radiation data measurements in Ghardaia site (32.360 N, 3.810 W, 450 m above MSL. Global solar radiation and surface temperatures were measured and analyzed for one complete year from 1 January-31December 2005. The data thus recorded are compared with corresponding data of the 22-year average of NASA's surface meteorology and solar energy-model. Hourly, daily and monthly solar radiation was made from five-minute recorded by EKO Pyranometer. The highest measured daily and monthly mean solar radiation was found to be 369 and 326 (W/m2, and the highest five minute averaged solar radiation values up to 1268 (W/m2 were observed in the summer season from May to September, and the yearly average daily energy input was 21.83 (MJ/m2/day. Besides the global solar radiation, the daily and monthly average temperature variations are discussed. The collected data indicate that Ghardaia has a strong potential for solar energy applications.

  13. CHAMP climate data based on inversion of monthly average bending angles

    Directory of Open Access Journals (Sweden)

    J. Danzer

    2014-07-01

    Full Text Available GNSS Radio Occultation (RO refractivity climatologies for the stratosphere can be obtained from the Abel inversion of monthly average bending-angle profiles. The averaging of large numbers of profiles suppresses random noise and this, in combination with simple exponential extrapolation above an altitude of 80 km, circumvents the need for a "statistical optimization" step in the processing. Using data from the US-Taiwanese COSMIC mission, which provides ~ 1500–2000 occultations per day, it has been shown that this Average-Profile Inversion (API technique provides a robust method for generating stratospheric refractivity climatologies. Prior to the launch of COSMIC in mid-2006, the data records rely on data from the CHAMP mission. In order to exploit the full range of available RO data, the usage of CHAMP data is also required. CHAMP only provided ~ 200 profiles per day, and the measurements were noisier than COSMIC. As a consequence, the main research question in this study was to see if the average bending angle approach is also applicable to CHAMP data. Different methods for suppression of random noise – statistical and through data quality pre-screening – were tested. The API retrievals were compared with the more conventional approach of averaging individual refractivity profiles, produced with the implementation of statistical optimization used in the EUMETSAT Radio Occultation Meteorology Satellite Application Facility (ROM SAF operational processing. In this study it is demonstrated that the API retrieval technique works well for CHAMP data, enabling the generation of long-term stratospheric RO climate data records from August 2001 and onward. The resulting CHAMP refractivity climatologies are found to be practically identical to the standard retrieval at the DMI below altitudes of 35 km. Between 35 km to 50 km the differences between the two retrieval methods started to increase, showing largest differences at high latitudes and

  14. NASA/GEWEX Surface Radiation Budget (SRB) Data and Info

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA/GEWEX Surface Radiation Budget (SRB) Release-3.0 data sets contains global 3-hourly, daily, monthly/3-hourly, and monthly averages of surface and top-of...

  15. Interannual variability of global radiation at Wageningen

    Science.gov (United States)

    Kane, R. P.

    1997-11-01

    A spectral analysis of the 12-monthly running means of the global radiation ratio Krobserved at Wageningen (52°N, 6°E) showed significant QBO, QTO (Quasi-biennial and Quasi-triennial Oscillations) and higher periodicities, with the strongest peak at ca.22 years but none at the solar cycle (11 years). All these are probably due to similar periodicities in cloudiness.

  16. Inter-comparison of the solar UVB, UVA and global radiation clearness and UV indices for Beer Sheva and Neve Zohar (Dead Sea), Israel

    Energy Technology Data Exchange (ETDEWEB)

    Kudish, A.I. [Ben Gurion University of the Negev, Beer Sheva (Israel). Solar Energy Laboratory; Dead Sea Research Center, Neve Zohar (Israel); Lyubansky, V.; Ianetz, A. [Israel Meteorological Service, Bet Dagan (Israel). Research Development Div.; Evseev, E.G. [Ben Gurion University of the Negev, Beer Sheva (Israel). Solar Energy Laboratory

    2005-07-01

    An inter-comparison of the clearness indices for the solar UVB, UVA and global radiation for Beer Sheva and Neve Zohar (Dead Sea) are presented utilizing radiation data measured from January 1995 through December 2001 for which there is a one-to-one correspondence between the measurements, viz., any day for which a hourly value for one of the sites was missing is rejected and not included in the analysis for that particular radiation type. Beer Sheva is located ca. 65 km to the west and is approximately 700 m above Neve Zohar, which is located on the western shore of the Dead Sea. The Dead Sea is the lowest terrestrial point on the earth, approximately 400 m below mean sea level. The relative magnitudes of the global, UVB and UVA radiation intensities at the two sites can be attributed to the enhanced scattering at the Dead Sea due to the longer optical path length the solar radiation must traverse at the Dead Sea. The degree of attenuation due to scattering phenomena is inversely proportional to the wavelength raised to some power and, consequently, it is greatest for UVB and very small for global radiation. The UVB and UVA solar constants were determined from the extraterrestrial radiation values tabulated by Froehlich and Wehrli [Spectral distribution of solar irradiance from 25000 nm to 250nm, in: M. Iqbal, An introduction to solar radiation, Academic Press, New York, 1981, Appendix C, pp. 380-381]. The clearness indices for global and UVA radiation were of similar magnitude, whereas those for UVB radiation were of two orders of magnitude smaller. In addition, the monthly average hourly UV Index at both sites has also been determined and an inter-comparison of the values has been performed for all available hourly values from January 1995 through August 2002 for both sites. It is observed that the monthly average hourly UV Index values at the Dead Sea are never in the extreme range. (author)

  17. Predicting Global Solar Radiation Using an Artificial Neural Network Single-Parameter Model

    Directory of Open Access Journals (Sweden)

    Karoro Angela

    2011-01-01

    Full Text Available We used five years of global solar radiation data to estimate the monthly average of daily global solar irradiation on a horizontal surface based on a single parameter, sunshine hours, using the artificial neural network method. The station under the study is located in Kampala, Uganda at a latitude of 0.19°N, a longitude of 32.34°E, and an altitude of 1200 m above sea level. The five-year data was split into two parts in 2003–2006 and 2007-2008; the first part was used for training, and the latter was used for testing the neural network. Amongst the models tested, the feed-forward back-propagation network with one hidden layer (65 neurons and with the tangent sigmoid as the transfer function emerged as the more appropriate model. Results obtained using the proposed model showed good agreement between the estimated and actual values of global solar irradiation. A correlation coefficient of 0.963 was obtained with a mean bias error of 0.055 MJ/m2 and a root mean square error of 0.521 MJ/m2. The single-parameter ANN model shows promise for estimating global solar irradiation at places where monitoring stations are not established and stations where we have one common parameter (sunshine hours.

  18. Global solar radiation estimation from relative sunshine hours in Yemen

    Energy Technology Data Exchange (ETDEWEB)

    Abdul-Aziz, J.; A-Nagi, A.; Zumailan, A.A.R. (Aden Univ. (Yemen, Republic of))

    1993-01-01

    The existing measurements of global solar radiation and sunshine duration for Yemen are examined. The errors of estimating global solar radiation from sunshine hour measurements using Angstrom's relation are evaluated. As a simple predictor for global solar radiation, an average Angstrom relation in the form H-bar/H[sub o] = 0.3518 + 0.3162 n/N for all stations is evaluated. Other Angstrom correlation relations are also proposed by classifying the stations under study into four groups. The estimated results are compared and seem to be satisfactory in the latter case. (Author)

  19. Analysis of the solar radiation data for Beer Sheva, Israel, and its environs

    Energy Technology Data Exchange (ETDEWEB)

    Kudish, A.I. (Ben-Gurion Univ. of the Negev, Beer Sheva (Israel)); Ianetz, A. (Israel Meteorological Service, Bet-Dagan (Israel))

    1992-01-01

    The solar radiation climate of Beer Sheva, Israel, is reported upon in detail. The database utilized in this analysis consisted of global radiation on a horizontal surface, normal incidence beam radiation, and global radiation on a south-facing surface tilted at 40{degree}. Monthly-average hourly and daily values are reported for each of these three types of measured radiations, together with the calculated monthly-average daily values for the components of the global radiation, viz. the horizontal beam and diffuse radiations. The monthly-average hourly and daily clearness index values have also been calculated and analyzed. Monthly-average daily frequency distributions of the clearness index values are reported for each month. The solar radiation climate of Beer Sheva has also been compared to those reported for a number of countries in this region. The annual-average daily global radiation incident on a horizontal surface is 18.91 MG/m{sup 2} and that for normal incidence beam radiation is 21.17 MG/m{sup 2}. The annual-average daily fraction of the horizontal global radiation that is beam is 0.72. The annual-average daily value for the clearness index is 0.587 and the average frequency of clear days annually is 58.6%. The authors conclude, based upon the above analysis, that Beer Sheva and its environs are characterized by relatively high, average-daily irradiation rates, both global and beam, and a relatively high frequency of clear days.

  20. Assessing the Performance of Global Solar Radiation Empirical ...

    African Journals Online (AJOL)

    Assessing the Performance of Global Solar Radiation Empirical Models at a ... such as simulation of crop performance and the design of solar energy conversion ... Three of these statistical performance indicators were combined to generate ...

  1. Evaluation of global, photosynthetically active radiation and diffuse radiation transmission of agricultural screens

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Gamez, M.; Suarez-Rey, E. M.; Castilla, N.; Soriano, T.

    2012-11-01

    Transmittance of a material depends on the type of radiation impinging on the material (direct or diffuse), the angle of incidence of the sun's rays (in direct radiation conditions) and the structure and characteristics of the material itself. The aim of this study was to evaluate the performance of nine agricultural screens of different densities, colours, thread diameters and porosities. A simple metal frame was used to quantify global, diffuse and photosynthetically active radiation (PAR) transmission to determine their transmittance values (as a function of the incidence angle of solar rays in direct radiation conditions) for global radiation and PAR, as well as the diffuse radiation transmitted characteristics of the screens (ratio of diffuse radiation to global radiation transmitted by screens). Non-coloured (translucent) screens contributed to a higher and more efficient proportion of diffuse radiation (Di/Gi {approx} 90%). The green screen behaved similarly to the non-coloured 20 × 10 type as far as global radiation was concerned, although the PAR transmittance values were lower (up to 12.4% at 15°). Variation in transmission according to diameter and density of the threads was greatest in the black screens. The non-coloured-thread screens may be the best option for maximising the transmission of diffuse radiation and the 6 × 6 green screen for vegetables cultivation during the summer in inland areas with latitudes close to 36degree N. (Author) 43 refs.

  2. Estimation of monthly global solar radiation in the eastern Mediterranean region in Turkey by using artificial neural networks

    Directory of Open Access Journals (Sweden)

    Sahan Muhittin

    2016-01-01

    Full Text Available In this study, an artificial neural network (ANN model was used to estimate monthly average global solar radiation on a horizontal surface for selected 5 locations in Mediterranean region for period of 18 years (1993-2010. Meteorological and geographical data were taken from Turkish State Meteorological Service. The ANN architecture designed is a feed-forward back-propagation model with one-hidden layer containing 21 neurons with hyperbolic tangent sigmoid as the transfer function and one output layer utilized a linear transfer function (purelin. The training algorithm used in ANN model was the Levenberg Marquand back propagation algorith (trainlm. Results obtained from ANN model were compared with measured meteorological values by using statistical methods. A correlation coefficient of 97.97 (~98% was obtained with root mean square error (RMSE of 0.852 MJ/m2, mean square error (MSE of 0.725 MJ/m2, mean absolute bias error (MABE 10.659MJ/m2, and mean absolute percentage error (MAPE of 4.8%. Results show good agreement between the estimated and measured values of global solar radiation. We suggest that the developed ANN model can be used to predict solar radiation another location and conditions.

  3. Estimation of monthly global solar radiation in the eastern Mediterranean region in Turkey by using artificial neural networks

    Science.gov (United States)

    Sahan, Muhittin; Yakut, Emre

    2016-11-01

    In this study, an artificial neural network (ANN) model was used to estimate monthly average global solar radiation on a horizontal surface for selected 5 locations in Mediterranean region for period of 18 years (1993-2010). Meteorological and geographical data were taken from Turkish State Meteorological Service. The ANN architecture designed is a feed-forward back-propagation model with one-hidden layer containing 21 neurons with hyperbolic tangent sigmoid as the transfer function and one output layer utilized a linear transfer function (purelin). The training algorithm used in ANN model was the Levenberg Marquand back propagation algorith (trainlm). Results obtained from ANN model were compared with measured meteorological values by using statistical methods. A correlation coefficient of 97.97 ( 98%) was obtained with root mean square error (RMSE) of 0.852 MJ/m2, mean square error (MSE) of 0.725 MJ/m2, mean absolute bias error (MABE) 10.659MJ/m2, and mean absolute percentage error (MAPE) of 4.8%. Results show good agreement between the estimated and measured values of global solar radiation. We suggest that the developed ANN model can be used to predict solar radiation another location and conditions.

  4. Contrasting regional versus global radiative forcing by megacity pollution emissions

    Science.gov (United States)

    Dang, H.; Unger, N.

    2015-10-01

    We assess the regional and global integrated radiative forcing on 20- and 100-year time horizons caused by a one-year pulse of present day pollution emissions from 10 megacity areas: Los Angeles, Mexico City, New York City, Sao Paulo, Lagos, Cairo, New Delhi, Beijing, Shanghai and Manila. The assessment includes well-mixed greenhouse gases: carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4); and short-lived climate forcers: tropospheric ozone (O3) and fine mode aerosol particles (sulfate, nitrate, black carbon, primary and secondary organic aerosol). All megacities contribute net global warming on both time horizons. Most of the 10 megacity areas exert a net negative effect on their own regional radiation budget that is 10-100 times larger in magnitude than their global radiative effects. Of the cities examined, Beijing, New Delhi, Shanghai and New York contribute most to global warming with values ranging from +0.03 to 0.05 Wm-2yr on short timescales and +0.07-0.10 Wm-2yr on long timescales. Regional net 20-year radiative effects are largest for Mexico City (-0.84 Wm-2yr) and Beijing (-0.78 Wm-2yr). Megacity reduction of non-CH4 O3 precursors to improve air quality offers zero co-benefits to global climate. Megacity reduction of aerosols to improve air quality offers co-benefits to the regional radiative budget but minimal or no co-benefits to global climate with the exception of black carbon reductions in a few cities, especially Beijing and New Delhi. Results suggest that air pollution and global climate change mitigation can be treated as separate environmental issues in policy at the megacity level with the exception of CH4 action. Individual megacity reduction of CO2 and CH4 emissions can mitigate global warming and therefore offers climate safety improvements to the entire planet.

  5. Global solar radiation estimation using sunshine duration in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Almorox, J.; Hontoria, C. [Universidad Politecnica de Madrid (Spain). Dpto. de Edafologia

    2004-06-01

    Several equations were employed to estimate global solar radiation from sunshine hours for 16 meteorological stations in Spain, using only the relative duration of sunshine. These equations included the original Angstrom-Prescott linear regression and modified functions (quadratic, third degree, logarithmic and exponential functions). Estimated values were compared with measured values in terms of the coefficient of determination, standard error of the estimate and mean absolute error. All the models fitted the data adequately and can be used to estimate global solar radiation from sunshine hours. This study finds that the third degree models performed better than the other models, but the linear model is preferred due to its greater simplicity and wider application. It is also found that seasonal partitioning does not significantly improve the estimation of global radiation. (author)

  6. Luminous efficacy of global solar radiation for clear skies

    Energy Technology Data Exchange (ETDEWEB)

    Robledo, L. [Universidad Politecnica de Madrid (Spain). Departamento de Sistemas Inteligentes Aplicados; Soler, A. [Universidad Politecnica de Madrid (Spain). Facultad de Ciencias Ambientales

    2000-11-01

    The luminous efficacy of global solar radiation for clear skies has been modeled using solar elevation as the only independent parameter. In the present work, two types of models are developed. On the one hand, polynomial models similar to those presented by other authors are produced, and on the other, a non-polynomial model for the luminous efficacy of global solar radiation is reported, as obtained from the ratio between the corresponding illuminance and irradiance models. This last mentioned model offers an accuracy to predict global illuminance similar to that obtained with the polynomial models. However, the model for the global efficacy obtained from illuminance and irradiance models has, among others, the advantage of its mathematical coherence, and its formulation uses a more definite function than the polynomial models. (author)

  7. Global impact of 3D cloud-radiation interactions

    Science.gov (United States)

    Schäfer, Sophia; Hogan, Robin; Fielding, Mark; Chiu, Christine

    2017-04-01

    Clouds have a decisive impact on the Earth's radiation budget and on the temperature of the atmosphere and surface. However, in global weather and climate models, cloud-radiation interaction is treated in only the vertical dimension using several non-realistic assumptions, which contributes to the large uncertainty on the climatic role of clouds. We provide a first systematic investigation into the impact of horizontal radiative transport for both shortwave and longwave radiation on a global, long-term scale. For this purpose, we have developed and validated the SPARTACUS radiation scheme, a method for including three-dimensional radiative transfer effects approximately in a one-dimensional radiation calculation that is numerically efficient enough for global calculations, allowing us to conduct 1D and quasi-3D radiation calculations for a year of global of ERA-Interim re-analysis atmospheric data and compare the results of various radiation treatments. SPARTACUS includes the effects of cloud internal inhomogeneity, horizontal in-region transport and the spatial distribution of in-cloud radiative fluxes.The impact of varying three-dimensional cloud geometry can be described by one parameter, the effective cloud scale, which has a characteristic value for each cloud type. We find that both the 3D effects of cloud-side transport and of horizontal in-cloud radiative transport in the shortwave are significant. Overall, 3D cloud effects warm the Earth by about 4 W m -2 , with warming effects in both the shortwave and the longwave. The dominant 3D cloud effect is the previously rarely investigated in-region horizontal transfer effect in the shortwave, which significantly decreases cloud reflectance and warms the Earth system by 5 W m -2 , partly counteracted by the cooling effect of shortwave 3D cloud-side transport. Longwave heating and cooling at various heights is strengthened by up to 0.2 K d ^{-1} and -0.3 K d ^{-1} respectively. These 3D effects, neglected by

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

    Science.gov (United States)

    Bilgili, Mehmet; Ozgoren, Muammer

    2011-05-01

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

  9. Characterization and simulation of hourly exposure series of global radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mora-Lopez, L. [Universidad de Malaga (Spain). Dpto. Lenguajes y C. Computacion; Sidrach-de-Cardona, M. [Universidad de Malaga (Spain). Dpto. Fisica Aplicada

    1997-06-01

    A statistical model which captures the main features of hourly exposure series of global radiation is proposed. This model is used to obtain a procedure to generate radiation series without imposing, a priori, any restriction on the form of the probability distribution function of the series. The statistical model was taken from the stationary stochastic processes theory. Data were obtained from ten different Spanish locations. As monthly hourly exposure series of global radiation are not stationary, they are modified in order to remove the observed trends. A multiplicative autoregressive moving average model with regular and seasonal components was used. It is statistically accepted that this is the true model which generates most of the analyzed sequences. However, the underlying parameters of the model vary from one location to another and from one month to another. Therefore, it is necessary to examine further the relationship between the parameters of the model and the available data from most locations. (author)

  10. The study of time series of monthly averaged values of F10.7 from 1950 to 2010

    CERN Document Server

    Bruevich, E A; Yakunina, G V

    2014-01-01

    Prior to 1947, the activity of the Sun was assessed by the relative numbers of sunspots (W). The 10.7 cm radio emission (frequency of 2.8 GHz) for observations of the variability of radiation of chromosphere and the lower corona (F10.7) became used from 1947. For the F10,7 are available more detailed observational archive data, so this activity index more often than the other indices is used in the prediction and monitoring of the solar activity. We have made the analysis of time series of F10.7 with the use of different mother wavelets: Daubechies 10, Symlet 8, Meyer, Gauss 8 and Morlet. Wavelet spectrum allows us not only to identify cycles, but analyze their change in time. Each wavelet has its own characteristic features, so sometimes with the help of different wavelets it can be better identify and highlight the different properties of the analyzed signal. We intended to choose the mother wavelet, which is more fully gives information about the analyzed index F10.7. We have received, that all these wavel...

  11. Operational Prototype Development of a Global Aircraft Radiation Exposure Nowcast

    Science.gov (United States)

    Mertens, Christopher; Kress, Brian; Wiltberger, Michael; Tobiska, W. Kent; Bouwer, Dave

    Galactic cosmic rays (GCR) and solar energetic particles (SEP) are the primary sources of human exposure to high linear energy transfer (LET) radiation in the atmosphere. High-LET radiation is effective at directly breaking DNA strands in biological tissue, or producing chemically active radicals in tissue that alter the cell function, both of which can lead to cancer or other adverse health effects. A prototype operational nowcast model of air-crew radiation exposure is currently under development and funded by NASA. The model predicts air-crew radiation exposure levels from both GCR and SEP that may accompany solar storms. The new air-crew radiation exposure model is called the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model. NAIRAS will provide global, data-driven, real-time exposure predictions of biologically harmful radiation at aviation altitudes. Observations are utilized from the ground (neutron monitors), from the atmosphere (the NCEP Global Forecast System), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations characterize the overhead mass shielding and the ground-and space-based observations provide boundary conditions on the incident GCR and SEP particle flux distributions for transport and dosimetry calculations. Radiation exposure rates are calculated using the NASA physics-based HZETRN (High Charge (Z) and Energy TRaNsport) code. An overview of the NAIRAS model is given: the concept, design, prototype implementation status, data access, and example results. Issues encountered thus far and known and/or anticipated hurdles to research to operations transition are also discussed.

  12. Prediction of global solar radiation and comparison with satellite data

    Science.gov (United States)

    Bakirci, Kadir

    2017-01-01

    Data on solar radiation at a related location is very necessary for many solar applications. In the present study, the models are derived to forecast the daily global solar radiation on horizontal plane for the Eastern Anatolia Region (EAR) of Turkey, covering thirteen provinces. The measured data on horizontal plane for the period of 1991-2005 are analyzed. The comparisons of calculated and measured values have been carried out with various statistical test methods. These statistical test methods are the mean bias error (MBE), the main percentage error (MPE), the root mean square error (RMSE) and t-statistic (t-stat). In addition, the comparisons of the solar radiation values of the National Aeronautics and Space Administration - Surface meteorology and Solar Energy (NASA-SSE) and calculated from the Model 3 with the higher determination coefficient is performed.

  13. Frequency-independent radiation modes of interior sound radiation: Experimental study and global active control

    Science.gov (United States)

    Hesse, C.; Papantoni, V.; Algermissen, S.; Monner, H. P.

    2017-08-01

    Active control of structural sound radiation is a promising technique to overcome the poor passive acoustic isolation performance of lightweight structures in the low-frequency region. Active structural acoustic control commonly aims at the suppression of the far-field radiated sound power. This paper is concerned with the active control of sound radiation into acoustic enclosures. Experimental results of a coupled rectangular plate-fluid system under stochastic excitation are presented. The amplitudes of the frequency-independent interior radiation modes are determined in real-time using a set of structural vibration sensors, for the purpose of estimating their contribution to the acoustic potential energy in the enclosure. This approach is validated by acoustic measurements inside the cavity. Utilizing a feedback control approach, a broadband reduction of the global acoustic response inside the enclosure is achieved.

  14. The global land Cryosphere Radiative Effect during the MODIS era

    Science.gov (United States)

    Singh, D.; Flanner, M. G.; Perket, J.

    2015-07-01

    Cryosphere Radiative Effect (CrRE) is the instantaneous influence of snow- and ice-cover on Earth's top of atmosphere (TOA) solar energy budget. Here, we apply measurements from the Moderate Resolution Imaging Spectrometer (MODIS), combined with microwave retrievals of snow presence and radiative kernels produced from 4 different models, to derive CrRE over global land during 2001-2013. We estimate global annual mean land CrRE during this period of -2.6 W m-2, with variations from -2.2 to -3.0 W m-2 resulting from use of different kernels, and variations of -2.4 to -2.6 W m-2 resulting from different algorithmic determinations of snow presence and surface albedo. Slightly more than half of the global land CrRE originates from perennial snow on Antarctica, whereas the majority of the Northern Hemisphere effect originates from seasonal snow. Consequently, the Northern Hemisphere land CrRE peaks at -6.0 W m-2 in April, whereas the Southern Hemisphere effect more closely follows the austral insolation cycle, peaking in December. Mountain glaciers resolved in 0.05° MODIS data contribute about -0.037 W m-2 (1.4 %) of the global effect, with the majority (94 %) of this contribution originating from the Himalayas. Inter-annual trends in the global annual mean land CrRE are not statistically significant during the MODIS era, but trends are positive (less negative) over large areas of Northern Asia, especially during spring, and slightly negative over Antarctica, possibly due to increased snowfall. During a common overlap period of 2001-2008, our MODIS estimates of the Northern Hemisphere land CrRE are about 18 % smaller (less negative) than previous estimates derived from coarse-resolution AVHRR data, though inter-annual variations are well correlated (r = 0.78), indicating that these data are useful in determining longer term trends in land CrRE.

  15. Estimation of clear sky hourly global solar radiation in Iraq

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jumaily, Kais J.; Al-Zuhairi, Munya F.; Mahdi, Zahraa S. [Department of Atmospheric Sciences, College of Science, Al-Mustansiriyah University, Baghdad (Iraq)

    2012-07-01

    The availability of hourly solar radiation data is very important for applications utilizing solar energy and for climate and environmental aspects. The aim of this work is to use a simple model for estimating hourly global solar radiation under clear sky condition in Iraq. Calculations were compared with measurements obtained from local station in Baghdad city and from Meteosat satellite data for different locations in Iraq. The statistical test methods of the mean bias error (MBE), root mean square error (RMSE) and t-test were used to evaluate the performance of the model. Results indicated that a fairly good agreement exists between calculated and measured values for all locations in Iraq. Since the model is independent of any meteorological variable, it would be of a practical use for rural areas where no meteorological data are available.

  16. [Comparison of three daily global solar radiation models].

    Science.gov (United States)

    Yang, Jin-Ming; Fan, Wen-Yi; Zhao, Ying-Hui

    2014-08-01

    Three daily global solar radiation estimation models ( Å-P model, Thornton-Running model and model provided by Liu Ke-qun et al.) were analyzed and compared using data of 13 weather stations from 1982 to 2012 from three northeastern provinces and eastern Inner Mongolia. After cross-validation analysis, the result showed that mean absolute error (MAE) for each model was 1.71, 2.83 and 1.68 MJ x m(-2) x d(-1) respectively, showing that Å-P model and model provided by Liu Ke-qun et al. which used percentage of sunshine had an advantage over Thornton-Running model which didn't use percentage of sunshine. Model provided by Liu Ke-qun et al. played a good effect on the situation of non-sunshine, and its MAE and bias percentage were 18.5% and 33.8% smaller than those of Å-P model, respectively. High precision results could be obtained by using the simple linear model of Å-P. Å-P model, Thornton-Running model and model provided by Liu Ke-qun et al. overvalued daily global solar radiation by 12.2%, 19.2% and 9.9% respectively. MAE for each station varied little with the spatial change of location, and annual MAE decreased with the advance of years. The reason for this might be that the change of observation accuracy caused by the replacement of radiation instrument in 1993. MAEs for rainy days, non-sunshine days and warm seasons of the three models were greater than those for days without rain, sunshine days and cold seasons respectively, showing that different methods should be used for different weather conditions on estimating solar radiation with meteorological elements.

  17. Hybrid methodology for hourly global radiation forecasting in Mediterranean area

    CERN Document Server

    Voyant, Cyril; Paoli, Christophe; Nivet, Marie Laure

    2012-01-01

    The renewable energies prediction and particularly global radiation forecasting is a challenge studied by a growing number of research teams. This paper proposes an original technique to model the insolation time series based on combining Artificial Neural Network (ANN) and Auto-Regressive and Moving Average (ARMA) model. While ANN by its non-linear nature is effective to predict cloudy days, ARMA techniques are more dedicated to sunny days without cloud occurrences. Thus, three hybrids models are suggested: the first proposes simply to use ARMA for 6 months in spring and summer and to use an optimized ANN for the other part of the year; the second model is equivalent to the first but with a seasonal learning; the last model depends on the error occurred the previous hour. These models were used to forecast the hourly global radiation for five places in Mediterranean area. The forecasting performance was compared among several models: the 3 above mentioned models, the best ANN and ARMA for each location. In t...

  18. General Formula for Estimation of Monthly Mean Global Solar Radiation in Different Climates on the South and North Coasts of Iran

    Directory of Open Access Journals (Sweden)

    Ali A. Sabziparvar

    2006-12-01

    Full Text Available Using sunshine duration, cloud cover, relative humidity, average of maximum temperature, and ground albedo as the input of several radiation models, the monthly average daily solar radiation on horizontal surface in various coastal cities of the South (25.23∘ N and the North (38.42∘ N of Iran are estimated. Several radiation models are tested and further are revised by taking into consideration the effects of relative humidity, ground albedo, and Sun-Earth distance. Model validation is performed by using up to 13 years (1988–2000 of daily solar observations. Errors are calculated using MBE, MABE, MPE, and RMSE statistical criteria (see nomenclature and further a general formula which estimates the global radiation in different climates of coastal regions is suggested. The proposed method shows a good agreement (less than 7% deviation with the long-term pyranometric data. In comparison with other works done so far, the suggested method performs a higher degree of accuracy for those of two regions. The model results can be extended to other locations in coastal regions where solar data are not available.

  19. The global land Cryosphere Radiative Effect during the MODIS era

    Directory of Open Access Journals (Sweden)

    D. Singh

    2015-07-01

    Full Text Available Cryosphere Radiative Effect (CrRE is the instantaneous influence of snow- and ice-cover on Earth's top of atmosphere (TOA solar energy budget. Here, we apply measurements from the Moderate Resolution Imaging Spectrometer (MODIS, combined with microwave retrievals of snow presence and radiative kernels produced from 4 different models, to derive CrRE over global land during 2001–2013. We estimate global annual mean land CrRE during this period of −2.6 W m-2, with variations from −2.2 to −3.0 W m-2 resulting from use of different kernels, and variations of −2.4 to −2.6 W m-2 resulting from different algorithmic determinations of snow presence and surface albedo. Slightly more than half of the global land CrRE originates from perennial snow on Antarctica, whereas the majority of the Northern Hemisphere effect originates from seasonal snow. Consequently, the Northern Hemisphere land CrRE peaks at −6.0 W m-2 in April, whereas the Southern Hemisphere effect more closely follows the austral insolation cycle, peaking in December. Mountain glaciers resolved in 0.05° MODIS data contribute about −0.037 W m-2 (1.4 % of the global effect, with the majority (94 % of this contribution originating from the Himalayas. Inter-annual trends in the global annual mean land CrRE are not statistically significant during the MODIS era, but trends are positive (less negative over large areas of Northern Asia, especially during spring, and slightly negative over Antarctica, possibly due to increased snowfall. During a common overlap period of 2001–2008, our MODIS estimates of the Northern Hemisphere land CrRE are about 18 % smaller (less negative than previous estimates derived from coarse-resolution AVHRR data, though inter-annual variations are well correlated (r = 0.78, indicating that these data are useful in determining longer term trends in land CrRE.

  20. Radiative transfer model for estimation of global solar radiation; Modelo de transferencia radiativa para la estimacion de la radiacion solar global

    Energy Technology Data Exchange (ETDEWEB)

    Pettazzi, A.; Sabon, C. S.; Souto, G. J. A.

    2004-07-01

    In this work, the efficiency of a radiative transfer model in estimating the annual solar global radiation has been evaluated, over different locations at Galicia, Spain, in clear sky periods. Due to its quantitative significance, special attention has been focused on the analysis of the influence of visibility over the global radiation. By comparison of both estimated and measured global solar radiation along year 2002, a typical annual visibility series was obtained over every location. These visibility values has been analysed in order to identify patterns and typical values, in order to be used to estimate the global solar radiation along a different year. Validation was done over the year 2003, obtaining an annual estimation less than 10 % different to the measured value. (Author)

  1. Ten-year global distribution of downwelling longwave radiation

    Directory of Open Access Journals (Sweden)

    K. G. Pavlakis

    2003-10-01

    Full Text Available Downwelling longwave fluxes, DLFs, have been derived for each month over a ten year period (1984–1993, on a global scale with a resolution of 2.5° × 2.5°.

    The fluxes were computed using a deterministic model for atmospheric radiation transfer, along with satellite and reanalysis data for the key atmospheric input parameters, i.e. cloud properties, and specific humidity and temperature profiles. The cloud climatologies were taken from the latest released and improved International Satellite Climatology Project D2 series. Specific humidity and temperature vertical profiles were taken from three different reanalysis datasets; NCEP/NCAR, GEOS, and ECMWF (acronyms explained in main text. DLFs were computed for each reanalysis dataset, with differences reaching values as high as 30 Wm−2 in specific regions, particularly over high altitude areas and deserts. However, globally, the agreement is good, with the rms of the difference between the DLFs derived from the different reanalysis datasets ranging from 5 to 7 Wm−2. The results are presented as geographical distributions and as time series of hemispheric and global averages. The DLF time series based on the different reanalysis datasets show similar seasonal and inter-annual variations, and similar anomalies related to the 86/87 El Niño and 89/90 La Niña events. The global ten-year average of the DLF was found to be between 342.2 Wm−2 and 344.3 Wm−2, depending on the dataset. We also conducted a detailed sensitivity analysis of the calculated DLFs to the key input data. Plots are given that can be used to obtain a quick assessment of the sensitivity of the DLF to each of the three key climatic quantities, for specific climatic conditions corresponding to different regions of the globe. Our model downwelling fluxes are validated against available data from ground-based stations distributed over the globe, as given by the Baseline

  2. A Bayesian Model Committee Approach to Forecasting Global Solar Radiation

    CERN Document Server

    Lauret, Philippe; Muselli, Marc; David, Mathieu; Diagne, Hadja; Voyant, Cyril

    2012-01-01

    This paper proposes to use a rather new modelling approach in the realm of solar radiation forecasting. In this work, two forecasting models: Autoregressive Moving Average (ARMA) and Neural Network (NN) models are combined to form a model committee. The Bayesian inference is used to affect a probability to each model in the committee. Hence, each model's predictions are weighted by their respective probability. The models are fitted to one year of hourly Global Horizontal Irradiance (GHI) measurements. Another year (the test set) is used for making genuine one hour ahead (h+1) out-of-sample forecast comparisons. The proposed approach is benchmarked against the persistence model. The very first results show an improvement brought by this approach.

  3. DNI measurements in the South of Portugal: Long term results through direct comparison with global and diffuse radiation measurements and existing time series

    Science.gov (United States)

    Cavaco, A.; Canhoto, P.; Costa, M. J.; Collares-Pereira, M.

    2016-05-01

    The present work describes the measurement effort for direct normal irradiance (DNI) evaluation in the sunny south of Portugal, with a network of eight radiation measurement stations in several locations (including Évora) providing a good coverage of the region. This new initiative for DNI measurement will still need many years (typically 10 or more) to produce a time series which can claim having long term statistical value. This problem can, however, be temporarily mitigated by measuring DNI at the same time as GHI and DHI, in a place where long term series dating back, already exist for those two. It so happens that a long term series (20 years) of global and diffuse solar irradiation exists for the location Évora. So the expectation is to establish correlations with the goal of attributing at least some long term statistical significance to the short and recent DNI series. The paper describes the setup of the measuring stations and presents the preliminary measurements obtained. It further presents the first correlations of monthly averages between normal beam (DNI), global and diffuse radiation. It then uses these correlations, admittedly without acceptable statistical significance (short series of less than one year of measured data), to exemplify how to get a prediction of long term DNI for Évora. This preliminary obtained value is compared to that predicted by the commercial data from Meteonorm.

  4. Development of a new Global RAdiation Belt model: GRAB

    Science.gov (United States)

    Sicard-Piet, Angelica; Lazaro, Didier; Maget, Vincent; Rolland, Guy; Ecoffet, Robert; Bourdarie, Sébastien; Boscher, Daniel; Standarovski, Denis

    2016-07-01

    The well known AP8 and AE8 NASA models are commonly used in the industry to specify the radiation belt environment. Unfortunately, there are some limitations in the use of these models, first due to the covered energy range, but also because in some regions of space, there are discrepancies between the predicted average values and the measurements. Therefore, our aim is to develop a radiation belt model, covering a large region of space and energy, from LEO altitudes to GEO and above, and from plasma to relativistic particles. The aim for the first version is to correct the AP8 and AE8 models where they are deficient or not defined. At geostationary, we developed ten years ago for electrons the IGE-2006 model which was proven to be more accurate than AE8, and used commonly in the industry, covering a broad energy range, from 1keV to 5MeV. From then, a proton model for geostationary orbit was also developed for material applications, followed by the OZONE model covering a narrower energy range but the whole outer electron belt, a SLOT model to asses average electron values for 2file system to switch between models, in order to obtain at each location in space and energy point the most reliable value. Of course, the way the model is developed is well suited to add new local developments or to include international partnership. This model will be called the GRAB model, as Global Radiation Belt model. We will present first beta version during this conference.

  5. Determination of atmospheric parameters to estimate global radiation in areas of complex topography: Generation of global irradiation map

    Energy Technology Data Exchange (ETDEWEB)

    Batlles, F.J.; Bosch, J.L. [Dpto. Fisica Aplicada, Universidad de Almeria, 04120 Almeria (Spain); Tovar-Pescador, J. [Dpto. Fisica, Universidad de Jaen, 23071 Jaen (Spain); Martinez-Durban, M. [Dpto. Ingenieria Lenguajes y Computacion, Universidad de Almeria, 04120 Almeria (Spain); Ortega, R. [Dpto. Edafologia y Quimica Agricola, Universidad de Almeria, 04120 Almeria (Spain); Miralles, I. [Dpto. Edafologia y Quimica Agricola, Universidad de Granada, 28071 Granada (Spain)

    2008-02-15

    Incoming shortwave solar radiation is an important parameter in environmental applications. A detailed spatial and temporal analysis of global solar radiation on the earth surface is needed in many applications, ranging from solar energy uses to the study of agricultural, forest and biological processes. At local scales, the topography is the most important factor in the distribution of solar radiation on the surface. The variability of the elevation, the surface orientation and the obstructions due to elevations are a source of great local differences in insolation and, consequently, in other variables as ground temperature. For this reason, several models based on GIS techniques have been recently developed, integrating topography to obtain the solar radiation on the surface. In this work, global radiation is analyzed with the Solar Analyst, a model implemented on ArcView, that computes the topographic parameters: altitude, latitude, slope and orientation (azimuth) and shadow effects. Solar Analyst uses as input parameters the diffuse fraction and the transmittance. These parameters are not usually available in radiometric networks in mountainous areas. In this work, a method to obtain both parameters from global radiation is proposed. Global radiation data obtained in two networks of radiometric stations is used: one located in Sierra Magina Natural Park (Spain) with 11 stations and another one located on the surroundings of Sierra Nevada Natural Park (Spain) with 14 stations. Daily solar irradiation is calculated from a digital terrain model (DTM), the daily diffuse fraction, K, and daily atmospheric transmittivity, {tau}. Results provided by the model have been compared with measured values. An overestimation for high elevations is observed, whereas low altitudes present underestimation. The best performance was also reported during summer months, and the worst results were obtained during winter. Finally, a yearly global solar irradiation map has been

  6. The potential of global solar radiation in the Silesia region as a renewable source of energy

    Directory of Open Access Journals (Sweden)

    Waniek Katarzyna

    2016-12-01

    Full Text Available Historically, Silesia has been at the centre of the Polish coal industry for many years and thus has experienced poorer air quality compared to other voivodeships. However, in recent years strong economic transformation in the area has led to a considerable reduction in coal production. This study aimed to assess the variability of global solar radiation at selected stations within the Silesian voivodeship, in order to re-evaluate the resources of renewable solar energy during the period 1994–2013. The theoretical potential of solar radiation was calculated based on a three-dimensional terrain model. The data on global solar radiation from 13 stations within the Silesia region, covering the period 1994–2013, were obtained from the Regional Inspectorate of Environmental Protection in Katowice. The most favourable conditions for the use of solar energy were found at the cities Sosnowiec and Cieszyn. The largest increase in global radiation over the research period was observed in Zabrze. The average annual global radiation ranged between 600–1300 kWh·m−2. Digital Elevation Models (DEM for selected districts of the Silesia region were used to calculate the theoretical potential of global solar radiation. The highest theoretical potential of global radiation was found in the district of Cieszyn, located at the highest altitude.

  7. Optimizing global liver function in radiation therapy treatment planning

    Science.gov (United States)

    Wu, Victor W.; Epelman, Marina A.; Wang, Hesheng; Romeijn, H. Edwin; Feng, Mary; Cao, Yue; Ten Haken, Randall K.; Matuszak, Martha M.

    2016-09-01

    Liver stereotactic body radiation therapy (SBRT) patients differ in both pre-treatment liver function (e.g. due to degree of cirrhosis and/or prior treatment) and radiosensitivity, leading to high variability in potential liver toxicity with similar doses. This work investigates three treatment planning optimization models that minimize risk of toxicity: two consider both voxel-based pre-treatment liver function and local-function-based radiosensitivity with dose; one considers only dose. Each model optimizes different objective functions (varying in complexity of capturing the influence of dose on liver function) subject to the same dose constraints and are tested on 2D synthesized and 3D clinical cases. The normal-liver-based objective functions are the linearized equivalent uniform dose (\\ell \\text{EUD} ) (conventional ‘\\ell \\text{EUD} model’), the so-called perfusion-weighted \\ell \\text{EUD} (\\text{fEUD} ) (proposed ‘fEUD model’), and post-treatment global liver function (GLF) (proposed ‘GLF model’), predicted by a new liver-perfusion-based dose-response model. The resulting \\ell \\text{EUD} , fEUD, and GLF plans delivering the same target \\ell \\text{EUD} are compared with respect to their post-treatment function and various dose-based metrics. Voxel-based portal venous liver perfusion, used as a measure of local function, is computed using DCE-MRI. In cases used in our experiments, the GLF plan preserves up to 4.6 % ≤ft(7.5 % \\right) more liver function than the fEUD (\\ell \\text{EUD} ) plan does in 2D cases, and up to 4.5 % ≤ft(5.6 % \\right) in 3D cases. The GLF and fEUD plans worsen in \\ell \\text{EUD} of functional liver on average by 1.0 Gy and 0.5 Gy in 2D and 3D cases, respectively. Liver perfusion information can be used during treatment planning to minimize the risk of toxicity by improving expected GLF; the degree of benefit varies with perfusion pattern. Although fEUD model optimization is computationally inexpensive and

  8. Optimizing global liver function in radiation therapy treatment planning

    Science.gov (United States)

    Wu, Victor W; Epelman, Marina A; Wang, Hesheng; Romeijn, H Edwin; Feng, Mary; Cao, Yue; Haken, Randall K Ten; Matuszak, Martha M

    2017-01-01

    Liver stereotactic body radiation therapy (SBRT) patients differ in both pre-treatment liver function (e.g. due to degree of cirrhosis and/or prior treatment) and radiosensitivity, leading to high variability in potential liver toxicity with similar doses. This work investigates three treatment planning optimization models that minimize risk of toxicity: two consider both voxel-based pre-treatment liver function and local-function-based radiosensitivity with dose; one considers only dose. Each model optimizes different objective functions (varying in complexity of capturing the influence of dose on liver function) subject to the same dose constraints and are tested on 2D synthesized and 3D clinical cases. The normal-liver-based objective functions are the linearized equivalent uniform dose (ℓEUD) (conventional ‘ℓEUD model’), the so-called perfusion-weighted ℓEUD (fEUD) (proposed ‘fEUD model’), and post-treatment global liver function (GLF) (proposed ‘GLF model’), predicted by a new liver-perfusion-based dose-response model. The resulting ℓEUD, fEUD, and GLF plans delivering the same target ℓEUD are compared with respect to their post-treatment function and various dose-based metrics. Voxel-based portal venous liver perfusion, used as a measure of local function, is computed using DCE-MRI. In cases used in our experiments, the GLF plan preserves up to 4.6%(7.5%) more liver function than the fEUD (ℓEUD) plan does in 2D cases, and up to 4.5%(5.6%) in 3D cases. The GLF and fEUD plans worsen in ℓEUD of functional liver on average by 1.0 Gy and 0.5 Gy in 2D and 3D cases, respectively. Liver perfusion information can be used during treatment planning to minimize the risk of toxicity by improving expected GLF; the degree of benefit varies with perfusion pattern. Although fEUD model optimization is computationally inexpensive and often achieves better GLF than ℓEUD model optimization does, the GLF model directly optimizes a more clinically

  9. A non-parametric method for correction of global radiation observations

    DEFF Research Database (Denmark)

    Bacher, Peder; Madsen, Henrik; Perers, Bengt;

    2013-01-01

    This paper presents a method for correction and alignment of global radiation observations based on information obtained from calculated global radiation, in the present study one-hour forecast of global radiation from a numerical weather prediction (NWP) model is used. Systematical errors detected...... in the observations are corrected. These are errors such as: tilt in the leveling of the sensor, shadowing from surrounding objects, clipping and saturation in the signal processing, and errors from dirt and wear. The method is based on a statistical non-parametric clear-sky model which is applied to both...... University. The method can be useful for optimized use of solar radiation observations for forecasting, monitoring, and modeling of energy production and load which are affected by solar radiation....

  10. Evaluation of long-term global radiation measurements in Denmark and Sweden

    DEFF Research Database (Denmark)

    Skalík, Lukáš; Lulkovičová, Otília; Furbo, Simon

    The climate, especially global radiation is one of the key factors influencing the energy yield of solar energy systems. In connection with planning and optimization of energy efficient buildings and solar energy systems it is important to know the climate data of the area where the buildings....../systems are located. This study is based on yearly and monthly values of global radiation based on measurements from a climate station placed on the roof of building 119 at Technical University of Denmark in Kgs. Lyngby, from different Danish climate stations runned by Danish Meteorological Institute and from...... different Swedish climate stations of Swedish Meteorological and Hydrological Institute. The global horizontal radiation has been measured for a high number of years at all of these stations. The values show a tendency of increased annual global radiation, most likely due to decreased pollution...

  11. Prediction of Global Solar Radiation in India Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Rajiv Gupta

    2016-06-01

    Full Text Available Increasing global warming and decreasing fossil fuel reserves has necessitated the use of renewable energy resources like solar energy in India. To maximize return on a solar farm, it had to be set up at a place with high solar radiation. The solar radiation values are available only for a small number of places and must be interpolated for the rest. This paper utilizes Artificial Neural Network in interpolation, by obtaining a function with input as combinations of 7 geographical and meteorological parameters affecting radiation, and output as global solar radiation. Data considered was of past 9 years for 13 Indian cities. Low error values and high coefficient of determination values thus obtained, verified that the results were accurate in terms of the original solar radiation data known. Thus, artificial neural network can be used to interpolate the solar radiation for the places of interest depending on the availability of the data.

  12. Clearness index estimation for spectral composition of direct and global solar radiations

    Energy Technology Data Exchange (ETDEWEB)

    Rahoma, U.A. [National Research Inst. of Astronomy and Geophysics, Helwan, Cairo (Egypt)

    2001-07-01

    Measurements of cloudless direct, global, and diffuse solar radiations, taken over a one year period at Helwan, are analyzed in terms of global index and diffuse fraction for clear-sky conditions. The dependence of the diffuse fraction on the global index was represented by a polynomial. These results support the use of routine instantaneous surface meteorological data to calculate global and diffuse radiations on a horizontal surface in the absence of any other radiation measurements. The spectral composition of the global solar-radiation was found to be 4.3% UV band, 32.5% band range 250-630 nm, 13.74% red band, 52.75% infrared band and 29.7% diffuse solar-radiation. The spectral distribution of direct solar-radiation ratio of the extraterrestrial solar radiation was found to be: 0.69% green and blue band, 47.5% yellow and orange band 45% red band, and 52.7% infra-red band. (author)

  13. Quantum Tunneling Radiation of Reissner-Nordstrom de Sitter Black Hole with a Global Monopole

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Applying Parikh's quantum tunneling model, we study the quantum tunneling radiation of ReissnerNordstrom de Sitter black hole with a global monopole. The result shows that the tunneling rates at the event horizon and the cosmic horizon are related to Bekenstein-Hawking entropy if we take the energy conservation into consideration,and the true radiate spectrum is not precisely thermal.

  14. Bayes统计模型在出山月均径流极小值研究中的应用%A Bayesian Analysis of Monthly Average Runoff Minima in Mountain Areas

    Institute of Scientific and Technical Information of China (English)

    刘友存; 霍雪丽; 郝永红; 崔玉环; 韩添丁; 沈永平; 王建

    2015-01-01

    Global warming has intensified hydrological extreme events and resulted in disasters around the world. For disaster management and adaption of extreme events,it is essential to improve the accuracy of extreme value statistical models. In this study,Bayes’Theorem is introduced to estimate parameters in the Generalized Pareto Distribution( GPD)model which is applied to simulate the distribution of monthly average runoff minima during dry periods in mountain areas of Ürümqi River. Bayes’Theorem treats parameters as random variables and provides machinery way to convert the prior distribution of parameters into a posterior distribution. Statistical inferences based on posterior distribution can provide a more comprehensive representation of the parameters. An improved Markov Chain Monte Carlo( MCMC)method,which can solve high-dimensional integral computation in the Bayes equation,is used to generate parameter simulations from the posterior distribution. Model diagnosis plots are made to guarantee the fitted GPD model is appropriate. Then based on the GPD model with Bayesian parameter esti-mates,monthly average minima corresponding to different return periods can be calculated. The results show that the improved MCMC method is able to make Markov chains converge at a high speed. Compared with the GPD model based on maximum likelihood parameter estimates,the GPD model based on Bayesian parameter estimates obtain more accurate estimations of minimum monthly average runoff. Moreover,the monthly average runoff minima in dry periods corresponding to 10 a,25 a,50 a and 100 a return periods are 0. 60 m3/s,0. 44 m3/s,0. 32 m3/s and 0. 20 m3/s respectively. The lower boundary of 95% confidence interval of 100a return level is -0. 238 m3/s,which implies that Ürümqi River is likely to cease when 100 a return level occurs in dry periods.%数理统计方法在解决全球气候变化引起的洪水、干旱等极端水文事件中获得了越来越广泛的

  15. Local and Global Radiative Feedback from Population III Star Formation

    CERN Document Server

    O'Shea, Brian W

    2010-01-01

    We present an overview of recent work that focuses on understanding the radiative feedback processes that are potentially important during Population III star formation. Specifically, we examine the effect of the Lyman-Werner (photodissociating) background on the early stages of primordial star formation, which serves to delay the onset of star formation in a given halo but never suppresses it entirely. We also examine the effect that both photodissociating and ionizing radiation in I-fronts from nearby stellar systems have on the formation of primordial protostellar clouds. Depending on the strength of the incoming radiation field and the central density of the halos, Pop III star formation can be suppressed, unaffected, or even enhanced. Understanding these and other effects is crucial to modeling Population III star formation and to building the earliest generations of galaxies in the Universe.

  16. Prediction of solar global radiation on a surface tilted to the south

    Science.gov (United States)

    Kudish, Avraham I.; Evseev, Efim G.

    2008-08-01

    Solar global and diffuse radiation intensities are, in general, measured on horizontal surfaces, whereas stationary solar conversion systems (both flat plate solar collector and PV) are tilted towards the sun in order to maximize the amount of solar radiation incident on the collector surface. Consequently, the solar radiation incident on a surface tilted to the south (northern hemisphere) must be determined by converting the solar radiation intensities measured on a horizontal surface to that incident on the tilted surface of interest. There exist a large number of models designed to perform such a conversion. Eleven such models have been tested utilizing data measured in Beer Sheva, Israel. The data consist of hourly solar global and diffuse radiation on a horizontal surface, normal incidence beam and global radiation on a south-oriented surface tilted at 40°. The individual model performance is assessed by an inter-comparison between the calculated and measured solar global radiation on the south-oriented surface tilted at 40° using both graphical and statistical methods. The relative performance of the different models under different sky conditions, i.e., clear, partially cloudy and cloudy as defined by the hourly clearness index value, has been studied.

  17. Spatio-temporal distribution of global solar radiation for Mexico using GOES data

    Science.gov (United States)

    Bonifaz, R.; Cuahutle, M.; Valdes, M.; Riveros, D.

    2013-05-01

    Increased need of sustainable and renewable energies around the world requires studies about the amount and distribution of such types of energies. Global solar radiation distribution in space and time is a key component on order to know the availability of the energy for different applications. Using GOES hourly data, the heliosat model was implemented for Mexico. Details about the model and its components are discussed step by stem an once obtained the global solar radiation images, different time datasets (hourly, daily, monthly and seasonal) were built in order to know the spatio-temporal behavior of this type of energy. Preliminary maps of the available solar global radiation energy for Mexico are presented, the amount and variation of the solar radiation by regions are analyzed and discussed. Future work includes a better parametrization of the model using calibrated ground stations data and more use of more complex models for better results.

  18. Comparative Study of Ground Measured, Satellite-Derived, and Estimated Global Solar Radiation Data in Nigeria

    Directory of Open Access Journals (Sweden)

    Boluwaji M. Olomiyesan

    2016-01-01

    Full Text Available In this study, the performance of three global solar radiation models and the accuracy of global solar radiation data derived from three sources were compared. Twenty-two years (1984–2005 of surface meteorological data consisting of monthly mean daily sunshine duration, minimum and maximum temperatures, and global solar radiation collected from the Nigerian Meteorological (NIMET Agency, Oshodi, Lagos, and the National Aeronautics Space Agency (NASA for three locations in North-Western region of Nigeria were used. A new model incorporating Garcia model into Angstrom-Prescott model was proposed for estimating global radiation in Nigeria. The performances of the models used were determined by using mean bias error (MBE, mean percentage error (MPE, root mean square error (RMSE, and coefficient of determination (R2. Based on the statistical error indices, the proposed model was found to have the best accuracy with the least RMSE values (0.376 for Sokoto, 0.463 for Kaduna, and 0.449 for Kano and highest coefficient of determination, R2 values of 0.922, 0.938, and 0.961 for Sokoto, Kano, and Kaduna, respectively. Also, the comparative study result indicates that the estimated global radiation from the proposed model has a better error range and fits the ground measured data better than the satellite-derived data.

  19. Use of hourly sequences of global radiation for simulation of photovoltaic systems grid connected

    Energy Technology Data Exchange (ETDEWEB)

    Sidrach de Cardona, M. [Dept. Fisica Aplicada 2, E.T.S.I., Univ. de Malaga (Spain); Mora Lopez, Ll. [Dept. Lenguajes y Ciencias de la Computacion, E.T.S.I., Univ. de Malaga (Spain)

    1996-12-31

    In this paper we analyse whether it is suitable to use hourly sequences of global radiation to study the performance of photovoltaic systems grid connected. The purpose of this paper is to quantify the error which is made on predicting the energy which a photovoltaic system connected to the grid, when the global radiation interval considered (which is an input value in our computations) varies. Using a simulation model we have studied how much energy is produced. The input values we considered are: values of daily global radiation, values of hourly global radiation and global radiation intervals of 10 minutes. These data have been recorded by the metereological station in Malaga of Andalusian Institute for renewable energies. In each interval, the simulation model takes into account the variations in module temperature as a function of ambient temperature. Therefore, when using daily values the model takes into account the average value of ambient temperature during sun hours and when using other values the model takes into account the average of this parameter in the interval under consideration. The nominal power considered is 2 kWp. The model we use assumes that the working point of the installation is always the maximum power point of modules and that all produced energy is injected in the grid. We also study the influence on this error when different set point of minimum input power for inverter starting (threshold value) are used. (orig.)

  20. Estimation of daily global solar radiation as a function of routine meteorological data in Mediterranean areas

    Science.gov (United States)

    Meza, Francisco Javier; Yebra, María Lorenzo

    2016-08-01

    Solar radiation is the main responsible of many processes of the biophysical environment. Temperature changes, snow melt dynamics, carbon sequestration, evaporation from soils, plants, and open water bodies are explained by the amount of radiation received in a surface. Lack of direct observations and insufficient record length limit the ability to use global solar radiation information for resource use management and planning. Based on the general equation of Bristow and Campbell, we propose a modification that allows us to better represent atmospheric transmissivity as a function of routine meteorological variables and improve estimates of global solar radiation in Mediterranean and semi arid areas. The improved Bristow-Campbell model (IBC) is easy to use in any location where measurements of temperature, precipitation, and relative humidity are available, and present a simple solution that can be used as proxy for relative humidity in case that variable is not been measured.

  1. Trapped-Ion Quantum Logic with Global Radiation Fields

    Science.gov (United States)

    Weidt, S.; Randall, J.; Webster, S. C.; Lake, K.; Webb, A. E.; Cohen, I.; Navickas, T.; Lekitsch, B.; Retzker, A.; Hensinger, W. K.

    2016-11-01

    Trapped ions are a promising tool for building a large-scale quantum computer. However, the number of required radiation fields for the realization of quantum gates in any proposed ion-based architecture scales with the number of ions within the quantum computer, posing a major obstacle when imagining a device with millions of ions. Here, we present a fundamentally different approach for trapped-ion quantum computing where this detrimental scaling vanishes. The method is based on individually controlled voltages applied to each logic gate location to facilitate the actual gate operation analogous to a traditional transistor architecture within a classical computer processor. To demonstrate the key principle of this approach we implement a versatile quantum gate method based on long-wavelength radiation and use this method to generate a maximally entangled state of two quantum engineered clock qubits with fidelity 0.985(12). This quantum gate also constitutes a simple-to-implement tool for quantum metrology, sensing, and simulation.

  2. Trapped-Ion Quantum Logic with Global Radiation Fields.

    Science.gov (United States)

    Weidt, S; Randall, J; Webster, S C; Lake, K; Webb, A E; Cohen, I; Navickas, T; Lekitsch, B; Retzker, A; Hensinger, W K

    2016-11-25

    Trapped ions are a promising tool for building a large-scale quantum computer. However, the number of required radiation fields for the realization of quantum gates in any proposed ion-based architecture scales with the number of ions within the quantum computer, posing a major obstacle when imagining a device with millions of ions. Here, we present a fundamentally different approach for trapped-ion quantum computing where this detrimental scaling vanishes. The method is based on individually controlled voltages applied to each logic gate location to facilitate the actual gate operation analogous to a traditional transistor architecture within a classical computer processor. To demonstrate the key principle of this approach we implement a versatile quantum gate method based on long-wavelength radiation and use this method to generate a maximally entangled state of two quantum engineered clock qubits with fidelity 0.985(12). This quantum gate also constitutes a simple-to-implement tool for quantum metrology, sensing, and simulation.

  3. Changes in global net radiative imbalance 1985–2012

    Science.gov (United States)

    Allan, Richard P; Liu, Chunlei; Loeb, Norman G; Palmer, Matthew D; Roberts, Malcolm; Smith, Doug; Vidale, Pier-Luigi

    2014-01-01

    Combining satellite data, atmospheric reanalyses, and climate model simulations, variability in the net downward radiative flux imbalance at the top of Earth's atmosphere (N) is reconstructed and linked to recent climate change. Over the 1985–1999 period mean N (0.34 ± 0.67 Wm−2) is lower than for the 2000–2012 period (0.62 ± 0.43 Wm−2, uncertainties at 90% confidence level) despite the slower rate of surface temperature rise since 2000. While the precise magnitude of N remains uncertain, the reconstruction captures interannual variability which is dominated by the eruption of Mount Pinatubo in 1991 and the El Niño Southern Oscillation. Monthly deseasonalized interannual variability in N generated by an ensemble of nine climate model simulations using prescribed sea surface temperature and radiative forcings and from the satellite-based reconstruction is significantly correlated (r∼0.6) over the 1985–2012 period. PMID:25821270

  4. Fourier transforms Investigation of Global Solar Radiation at True Noon: in the Desert climatology

    OpenAIRE

    U. A. Rahoma; A. H. Hassan

    2007-01-01

    The aim of this work has been to obtain a typical annual time a function by the application of a calculation procedure based on a Fourier analysis to global solar radiation data of nine years at Helwan Egypt from June 1991 to August 1999. This function allows us to estimate the most probable values of the horizontal daily global solar radiation for every day of the year at Helwan Egypt. It is confirmed that the harmonic model presents an important percentage with 98% confidence bounds. The ap...

  5. The global land shortwave cryosphere radiative effect during the MODIS era

    OpenAIRE

    2015-01-01

    The shortwave cryosphere radiative effect (CrRE) is the instantaneous influence of snow and ice cover on Earth's top-of-atmosphere (TOA) solar energy budget. Here, we apply measurements from the MODerate resolution Imaging Spectroradiometer (MODIS), combined with microwave retrievals of snow presence and radiative kernels produced from four different models, to derive CrRE over global land during 2001–2013. We estimate global annual-mean land CrRE during this period of −2.6 W m...

  6. A revisit to decadal change of aerosol optical depth and its impact on global radiation over China

    Science.gov (United States)

    Tang, Wenjun; Yang, Kun; Qin, Jun; Niu, Xiaolei; Lin, Changgui; Jing, Xianwen

    2017-02-01

    Global radiation over China decreased between the 1960s and 1990, since when it has remained stable. As the total cloud cover has continued to decrease since the 1960s, variations in aerosols were suggested in previous studies to be the primary cause for variations in global radiation over China. However, the effect of aerosols on global radiation on a decadal scale has not been physically quantified over China. In this study, aerosol optical depth (AOD) data since 1980 are estimated by combining horizontal visibility data at stations in China and AOD observed by the moderate resolution imaging spectroradiometer (MODIS). It is found that the AOD exhibits decadal changes, with two decreasing periods (before the end of 1980s and after 2006) and one increasing period (from 1990 to 2006). With the derived AOD, a clear-sky model is then applied to quantify the role of aerosols in the variations in global radiation over China. The results show that aerosol direct effect cannot fully explain the decadal variations in the global radiation over China between 1980 and 2010, though it has a considerable effect on global radiation climatology. There are significant differences between the trends of clear-sky global radiation impacted by aerosols and those of all-sky global radiation impacted by aerosols and clouds, and the correlation coefficient for the comparison is very low. Therefore, the variations in all-sky global radiation over China are likely to be due to changes in cloud properties and to interactions between clouds and aerosols.

  7. Hawking radiation from the Schwarzschild black hole with a global monopole via gravitational anomaly

    Institute of Scientific and Technical Information of China (English)

    Peng Jun-Jin; Wu Shuang-Qing

    2008-01-01

    This paper derives the Hawking flux from the Schwarzschild black hole with a global monopole by using Robinson and Wilczek's method.Adopting a dimensional reduction technique, it can describe the effective quantum field in the (3+1)-dimensional global monopole background by an infinite collection of the (1+1)-dimensional maesless fields if neglecting the ingoing modes near the horizon, where the gravitational anomaly can be cancelled by the (1+1)-dimensional black body radiation at the Hawking temperature.

  8. UV radiation in global climate change. Measurements, modeling and effects on ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wei; Slusser, James R. (eds.) [Colorado State Univ., CO (United States). Natural Resource Ecology Lab.; Schmoldt, Daniel L. [Waterfront Centre, Washington, DC (United States). Cooperative State Research Education and Extension Service

    2010-07-01

    Numerous studies report that ultraviolet (UV) radiation is harmful to living organisms and detrimental to human health. Growing concerns regarding the increased levels of UV-B radiation that reach the earth's surface have led to the development of ground- and space-based measurement programs. Further study is needed on the measurement, modeling, and effects of UV radiation. The chapters of this book describe the research conducted across the globe over the past three decades in the areas of: (1) current and predicted levels of UV radiation and its associated impact on ecosystems and human health, as well as economic and social implications; (2) new developments in UV instrumentation, advances in calibration (ground- and satellite-based), measurement methods, modeling efforts, and their applications; and (3) the effects of global climate change on UV radiation. (orig.)

  9. A Global Three-dimensional Radiation Magneto-hydrodynamic Simulation of Super-Eddington Accretion Disks

    Science.gov (United States)

    Jiang, Yan-Fei; Stone, James M.; Davis, Shane W.

    2014-12-01

    We study super-Eddington accretion flows onto black holes using a global three-dimensional radiation magneto-hydrodynamical simulation. We solve the time-dependent radiative transfer equation for the specific intensities to accurately calculate the angular distribution of the emitted radiation. Turbulence generated by the magneto-rotational instability provides self-consistent angular momentum transfer. The simulation reaches inflow equilibrium with an accretion rate ~220 L Edd/c 2 and forms a radiation-driven outflow along the rotation axis. The mechanical energy flux carried by the outflow is ~20% of the radiative energy flux. The total mass flux lost in the outflow is about 29% of the net accretion rate. The radiative luminosity of this flow is ~10 L Edd. This yields a radiative efficiency ~4.5%, which is comparable to the value in a standard thin disk model. In our simulation, vertical advection of radiation caused by magnetic buoyancy transports energy faster than photon diffusion, allowing a significant fraction of the photons to escape from the surface of the disk before being advected into the black hole. We contrast our results with the lower radiative efficiencies inferred in most models, such as the slim disk model, which neglect vertical advection. Our inferred radiative efficiencies also exceed published results from previous global numerical simulations, which did not attribute a significant role to vertical advection. We briefly discuss the implications for the growth of supermassive black holes in the early universe and describe how these results provided a basis for explaining the spectrum and population statistics of ultraluminous X-ray sources.

  10. A global three-dimensional radiation magneto-hydrodynamic simulation of super-eddington accretion disks

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yan-Fei [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Stone, James M. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Davis, Shane W. [Canadian Institute for Theoretical Astrophysics. Toronto, ON M5S3H4 (Canada)

    2014-12-01

    We study super-Eddington accretion flows onto black holes using a global three-dimensional radiation magneto-hydrodynamical simulation. We solve the time-dependent radiative transfer equation for the specific intensities to accurately calculate the angular distribution of the emitted radiation. Turbulence generated by the magneto-rotational instability provides self-consistent angular momentum transfer. The simulation reaches inflow equilibrium with an accretion rate ∼220 L {sub Edd}/c {sup 2} and forms a radiation-driven outflow along the rotation axis. The mechanical energy flux carried by the outflow is ∼20% of the radiative energy flux. The total mass flux lost in the outflow is about 29% of the net accretion rate. The radiative luminosity of this flow is ∼10 L {sub Edd}. This yields a radiative efficiency ∼4.5%, which is comparable to the value in a standard thin disk model. In our simulation, vertical advection of radiation caused by magnetic buoyancy transports energy faster than photon diffusion, allowing a significant fraction of the photons to escape from the surface of the disk before being advected into the black hole. We contrast our results with the lower radiative efficiencies inferred in most models, such as the slim disk model, which neglect vertical advection. Our inferred radiative efficiencies also exceed published results from previous global numerical simulations, which did not attribute a significant role to vertical advection. We briefly discuss the implications for the growth of supermassive black holes in the early universe and describe how these results provided a basis for explaining the spectrum and population statistics of ultraluminous X-ray sources.

  11. Global analysis of radiative forcing from fire-induced shortwave albedo change

    Directory of Open Access Journals (Sweden)

    G. López-Saldaña

    2014-05-01

    Full Text Available Land surface albedo, a key parameter to derive Earth's surface energy balance, is used in the parameterization of numerical weather prediction, climate monitoring and climate change impact assessments. Changes in albedo due to fire have not been fully investigated at continental and global scale. The main goal of this study therefore, is to quantify the changes in albedo produced by biomass burning activities and their associated shortwave radiative forcing. The study relies on the Moderate Resolution Imaging Spectroradiometer (MODIS MCD64A1 burned area product to create an annual composite of areas affected by fire and the MCD43C2 BRDF-Albedo snow-free product to compute a bihemispherical reflectance time series. The approximate day of burn is used to calculate the instantaneous change in shortwave Albedo. Using the corresponding National Centers for Environmental Prediction (NCEP monthly mean downward solar radiation flux at the surface, the global radiative forcing associated to fire was computed. The analysis reveals a mean decrease in shortwave albedo of −0.023 (1σ = 0.018 causing a mean positive radiative forcing of 6.31 W m–2 (1σ = 5.04 over the 2002–2012 time period in areas affected by fire. The greatest drop in mean shortwave albedo change occurs in 2002, which corresponds to the highest total area burnt (3.66 Mha observed in the same year and produces the highest mean radiative forcing (6.75 W m–2. Africa is the main contributor in terms of burned area but forests globally are giving the highest radiative forcing per unit area, thus give detectable changes in shortwave albedo. The global mean radiative forcing for the whole studied period ~ 0.04 W m–2 shows that the contribution of fires into the Earth system is not insignificant.

  12. Global fine-mode aerosol radiative effect, as constrained by comprehensive observations

    Science.gov (United States)

    Chung, Chul E.; Chu, Jung-Eun; Lee, Yunha; van Noije, Twan; Jeoung, Hwayoung; Ha, Kyung-Ja; Marks, Marguerite

    2016-07-01

    Aerosols directly affect the radiative balance of the Earth through the absorption and scattering of solar radiation. Although the contributions of absorption (heating) and scattering (cooling) of sunlight have proved difficult to quantify, the consensus is that anthropogenic aerosols cool the climate, partially offsetting the warming by rising greenhouse gas concentrations. Recent estimates of global direct anthropogenic aerosol radiative forcing (i.e., global radiative forcing due to aerosol-radiation interactions) are -0.35 ± 0.5 W m-2, and these estimates depend heavily on aerosol simulation. Here, we integrate a comprehensive suite of satellite and ground-based observations to constrain total aerosol optical depth (AOD), its fine-mode fraction, the vertical distribution of aerosols and clouds, and the collocation of clouds and overlying aerosols. We find that the direct fine-mode aerosol radiative effect is -0.46 W m-2 (-0.54 to -0.39 W m-2). Fine-mode aerosols include sea salt and dust aerosols, and we find that these natural aerosols result in a very large cooling (-0.44 to -0.26 W m-2) when constrained by observations. When the contribution of these natural aerosols is subtracted from the fine-mode radiative effect, the net becomes -0.11 (-0.28 to +0.05) W m-2. This net arises from total (natural + anthropogenic) carbonaceous, sulfate and nitrate aerosols, which suggests that global direct anthropogenic aerosol radiative forcing is less negative than -0.35 W m-2.

  13. Using probabilistic finite automata to simulate hourly series of global radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mora-Lopez, L. [Universidad de Malaga (Spain). Dpto. Lenguajes y Computacion; Sidrach-de-Cardona, M. [Universidad de Malaga (Spain). Dpto. Fisica Aplicada II

    2003-03-01

    A model to generate synthetic series of hourly exposure of global radiation is proposed. This model has been constructed using a machine learning approach. It is based on the use of a subclass of probabilistic finite automata which can be used for variable-order Markov processes. This model allows us to represent the different relationships and the representative information observed in the hourly series of global radiation; the variable-order Markov process can be used as a natural way to represent different types of days, and to take into account the ''variable memory'' of cloudiness. A method to generate new series of hourly global radiation, which incorporates the randomness observed in recorded series, is also proposed. As input data this method only uses the mean monthly value of the daily solar global radiation. We examine if the recorded and simulated series are similar. It can be concluded that both series have the same statistical properties. (author)

  14. Determination of global Earth outgoing radiation at high temporal resolution using a theoretical constellation of satellites

    Science.gov (United States)

    Gristey, Jake J.; Chiu, J. Christine; Gurney, Robert J.; Han, Shin-Chan; Morcrette, Cyril J.

    2017-01-01

    New, viable, and sustainable observation strategies from a constellation of satellites have attracted great attention across many scientific communities. Yet the potential for monitoring global Earth outgoing radiation using such a strategy has not been explored. To evaluate the potential of such a constellation concept and to investigate the configuration requirement for measuring radiation at a time resolution sufficient to resolve the diurnal cycle for weather and climate studies, we have developed a new recovery method and conducted a series of simulation experiments. Using idealized wide field-of-view broadband radiometers as an example, we find that a baseline constellation of 36 satellites can monitor global Earth outgoing radiation reliably to a spatial resolution of 1000 km at an hourly time scale. The error in recovered daily global mean irradiance is 0.16 W m-2 and -0.13 W m-2, and the estimated uncertainty in recovered hourly global mean irradiance from this day is 0.45 W m-2 and 0.15 W m-2, in the shortwave and longwave spectral regions, respectively. Sensitivity tests show that addressing instrument-related issues that lead to systematic measurement error remains of central importance to achieving similar accuracies in reality. The presented error statistics therefore likely represent the lower bounds of what could currently be achieved with the constellation approach, but this study demonstrates the promise of an unprecedented sampling capability for better observing the Earth's radiation budget.

  15. GLOBAL SOLAR RADIATION INTERCEPTION BY GRAPEVINES TRAINED TO A VERTICAL TRELLIS SYSTEM

    Directory of Open Access Journals (Sweden)

    CLAUDIA GUIMARÃES CAMARGO CAMPOS

    2016-01-01

    Full Text Available ABSTRACT In this paper we assess the utilization of radiant energy in the growing of grapevines (Cabernet Sauvignon trained to a vertical trellis system, and estimate the global solar radiation interception taking into account the physical characteristics of the training system at different phenological stages. The experiment was based on daily measurements of global solar radiation made by an automatic weather station placed at the vineyard of a winery located in the municipality of São Joaquim, in the southern Brazilian State of Santa Catarina (Villa Francioni winery, 28º 15’ 14” S, 49º 57’ 02” W, 1294m a.s.l.. Growth and phenological development of the shoots were evaluated. The global solar radiation is intercepted by the canopy (trained to a vertical trellis system in different orientations and the accumulated total is slightly greater on the east than on the west face of the canopy, especially after flowering. The daily variability of global solar radiation intercepted by the canopy is greater after flowering. The accumulated solar energy incident on the canopy increases until the onset of ripening. From the results, vineyards trained to a vertical trellis system in the north-south direction provide favorable sunlight exposure to leaves and fruits and are promising in quality and productivity.

  16. Prediction of monthly mean daily global solar radiation using Artificial Neural Network

    Indian Academy of Sciences (India)

    V Sivamadhavi; R Samuel Selvaraj

    2012-12-01

    In this study, a multilayer feed forward (MLFF) neural network based on back propagation algorithm was developed, trained, and tested to predict monthly mean daily global radiation in Tamil Nadu, India. Various geographical, solar and meteorological parameters of three different locations with diverse climatic conditions were used as input parameters. Out of 565 available data, 530 were used for training and the rest were used for testing the artificial neural network (ANN). A 3-layer and a 4-layer MLFF networks were developed and the performance of the developed models was evaluated based on mean bias error, mean absolute percentage error, root mean squared error and Student’s -test. The 3-layer MLFF network developed in this study did not give uniform results for the three chosen locations. Hence, a 4-layer MLFF network was developed and the average value of the mean absolute percentage error was found to be 5.47%. Values of global radiation obtained using the model were in excellent agreement with measured values. Results of this study show that the designed ANN model can be used to estimate monthly mean daily global radiation of any place in Tamil Nadu where measured global radiation data are not available.

  17. Biomass burning emissions estimated with a global fire assimilation system based on observed fire radiative power

    NARCIS (Netherlands)

    Kaiser, J.W.; Heil, A.; Andreae, M.O.; Benedetti, A.; Chubarova, N.; Jones, L.; Morcrette, J.J.; Razinger, M.; Schultz, M.G.; Suttie, M.; Werf, van der G.R.

    2012-01-01

    The Global Fire Assimilation System (GFASv1.0) calculates biomass burning emissions by assimilating Fire Radiative Power (FRP) observations from the MODIS instruments onboard the Terra and Aqua satellites. It corrects for gaps in the observations, which are mostly due to cloud cover, and filters spu

  18. Correlations between values of daily beam, diffuse and global radiation for Beer Sheva, Israel

    Energy Technology Data Exchange (ETDEWEB)

    Ianetz, A. (Israel Meteorological Service, Bet Dagan (Israel). Research and Development Dept.); Kudish, A.I. (Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Chemical Engineering)

    1992-06-01

    Empirical correlations for predicting both beam and diffuse radiation at Beer Sheva, located in the semi-arid southern region of Israel, have been developed. These equations relate either the beam or the diffuse fraction of the global radiation to the clearness index. The available data, composed of normal incidence beam and global radiation measurements, have been analyzed on both a seasonal and a yearly basis. They have been compared to empirical equations previously reported in the literature for six sites in the Middle East region. In the case of Qidron, Israel, and three Greek sites, there was close agreement between the correlations, whereas in the remaining two sites (Gilat, Israel and Fudhaliyah, Iraq) the correlations were quite different. Reasons for the discrepancies in the latter two cases are presented in the text. (author).

  19. Modeling Study of the Global Distribution of Radiative Forcing by Dust Aerosol

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; MA Jinghui; ZHENG Youfei

    2010-01-01

    To quantitatively understand the dust aerosol effects on climate change, we calculated the global dis-tribution of direct radiative forcing due to dust aerosol under clear and cloudy skies in both winter and summer, by using an improved radiative transfer model and the global distribution of dust mass concentra-tion given by GADS (Global Aerosol Data Set). The results show that the global means of the solar forcing due to dust aerosol at the tropopause for winter and summer are -0.48 and -0.50 W m-2, respectively; the corresponding values for the longwave forcing due to dust are 0.11 and 0.09 W m-2, respectively. At the surface, the global means of the solar forcing clue to dust are -1.36 W m-2 for winter and -1.56 W m-2 for summer, whereas the corresponding values for the longwave forcing are 0.27 and 0.23 W m-2, respectively. This work points out that the absolute values of the solar forcing due to dust aerosol at both the tropopause and surface increase linearly with the cosine of solar zenith angle and surface albedo. The solar zenith angle influences both the strength and distribution of the solar forcing greatly. Clouds exert great effects on the direct radiative forcing of dust, depending on many factors including cloud cover, cloud height, cloud water path, surface albedo, solar zenith angle, etc. The effects of low clouds and middle clouds are larger than those of high clouds. The existence of clouds reduces the longwave radiative forcing at the tropopause, where the influences of low clouds are the most obvious. Therefore, the impacts of clouds should not be ignored when estimating the direct radiative forcing due to dust aerosol.

  20. Building global and diffuse solar radiation series and assessing decadal trends in Girona (NE Iberian Peninsula)

    Science.gov (United States)

    Calbó, Josep; González, Josep-Abel; Sanchez-Lorenzo, Arturo

    2016-05-01

    Measurement of solar radiation was initiated in Girona, northeast of the Iberian Peninsula, in the late 1980s. Initially, two pyranometers were installed, one of them equipped with a shadowband for measuring the diffuse component. Two other pyranometers currently exist, both ventilated and one of them shadowed, with a sphere, and a pyrheliometer for measuring direct radiation. Additional instruments for other shortwave and longwave components, clouds, and atmospheric aerosols have been installed in recent years. The station is subject to daily inspection, data are saved at high temporal resolution, and instruments are periodically calibrated, all in accordance with the directions of the Baseline Surface Radiation Network. The present paper describes how the entire series of global solar radiation (1987-2014) and diffuse radiation (1994-2014) were built, including the quality control process. Appropriate corrections to the diffuse component were made when a shadowband was employed to make measurements. Analysis of the series reveals that annual mean global irradiance presents a statistically significant increase of 2.5 W m-2 (1.4 %) decade-1 (1988-2014 period), mainly due to what occurs in summer (5.6 W m-2 decade-1). These results constitute the first assessment of solar radiation trends for the northeastern region of the Iberian Peninsula and are consistent with trends observed in the regional surroundings and also by satellite platforms, in agreement with the global brightening phenomenon. Diffuse radiation has decreased at -1.3 W m-2 (-2 %) decade-1 (1994-2014 period), which is a further indication of the reduced cloudiness and/or aerosol load causing the changes.

  1. Global Surface Net-Radiation at 5 km from MODIS Terra

    Directory of Open Access Journals (Sweden)

    Manish Verma

    2016-09-01

    Full Text Available Reliable and fine resolution estimates of surface net-radiation are required for estimating latent and sensible heat fluxes between the land surface and the atmosphere. However, currently, fine resolution estimates of net-radiation are not available and consequently it is challenging to develop multi-year estimates of evapotranspiration at scales that can capture land surface heterogeneity and are relevant for policy and decision-making. We developed and evaluated a global net-radiation product at 5 km and 8-day resolution by combining mutually consistent atmosphere and land data from the Moderate Resolution Imaging Spectroradiometer (MODIS on board Terra. Comparison with net-radiation measurements from 154 globally distributed sites (414 site-years from the FLUXNET and Surface Radiation budget network (SURFRAD showed that the net-radiation product agreed well with measurements across seasons and climate types in the extratropics (Wilmott’s index ranged from 0.74 for boreal to 0.63 for Mediterranean sites. Mean absolute deviation between the MODIS and measured net-radiation ranged from 38.0 ± 1.8 W∙m−2 in boreal to 72.0 ± 4.1 W∙m−2 in the tropical climates. The mean bias was small and constituted only 11%, 0.7%, 8.4%, 4.2%, 13.3%, and 5.4% of the mean absolute error in daytime net-radiation in boreal, Mediterranean, temperate-continental, temperate, semi-arid, and tropical climate, respectively. To assess the accuracy of the broader spatiotemporal patterns, we upscaled error-quantified MODIS net-radiation and compared it with the net-radiation estimates from the coarse spatial (1° × 1° but high temporal resolution gridded net-radiation product from the Clouds and Earth’s Radiant Energy System (CERES. Our estimates agreed closely with the net-radiation estimates from the CERES. Difference between the two was less than 10 W·m−2 in 94% of the total land area. MODIS net-radiation product will be a valuable resource for the

  2. Dust vertical profile impact on global radiative forcing estimation using a coupled chemical-transport–radiative-transfer model

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2013-07-01

    Full Text Available Atmospheric mineral dust particles exert significant direct radiative forcings and are important drivers of climate and climate change. We used the GEOS-Chem global three-dimensional chemical transport model (CTM coupled with the Fu-Liou-Gu (FLG radiative transfer model (RTM to investigate the dust radiative forcing and heating rate based on different vertical profiles for April 2006. We attempt to actually quantify the sensitivities of radiative forcing to dust vertical profiles, especially the discrepancies between using realistic and climatological vertical profiles. In these calculations, dust emissions were constrained by observations of aerosol optical depth (AOD. The coupled calculations utilizing a more realistic dust vertical profile simulated by GEOS-Chem minimize the physical inconsistencies between 3-D CTM aerosol fields and the RTM. The use of GEOS-Chem simulated vertical profile of dust extinction, as opposed to the FLG prescribed vertical profile, leads to greater and more spatially heterogeneous changes in the estimated radiative forcing and heating rate produced by dust. Both changes can be attributed to a different vertical structure between dust and non-dust source regions. Values of the dust vertically resolved AOD per grid level (VRAOD are much larger in the middle troposphere, though smaller at the surface when the GEOS-Chem simulated vertical profile is used, which leads to a much stronger heating rate in the middle troposphere. Compared to the FLG vertical profile, the use of GEOS-Chem vertical profile reduces the solar radiative forcing at the top of atmosphere (TOA by approximately 0.2–0.25 W m−2 over the African and Asian dust source regions. While the Infrared (IR radiative forcing decreases 0.2 W m−2 over African dust belt, it increases 0.06 W m−2 over the Asian dust belt when the GEOS-Chem vertical profile is used. Differences in the solar radiative forcing at the surface between the use of the GEOS-Chem and

  3. The Potential Radiative Forcing of Global Land Use and Land Cover Change Activities

    Science.gov (United States)

    Ward, D. S.; Mahowald, N. M.; Kloster, S.

    2014-12-01

    Given the expected increase in pressure on land resources over the next century, there is a need to understand the total impacts of activities associated with land use and land cover change (LULCC). Here we quantify these impacts using the radiative forcing metric, including forcings from changes in long-lived greenhouse gases, tropospheric ozone, aerosol effects, and land surface albedo. We estimate radiative forcings from the different agents for historical LULCC and for six future projections using simulations from the National Center for Atmospheric Research Community Land Model and Community Atmosphere Models and additional offline analyses. When all forcing agents are considered together we show that 45% (+30%, -20%) of the present-day (2010) anthropogenic radiative forcing can be attributed to LULCC. Changes in the emission of non-CO2 greenhouse gases and aerosols from LULCC enhance the total LULCC radiative forcing by a factor of 2 to 3 with respect to the forcing from CO2 alone. In contrast, the non-CO2 forcings from fossil fuel burning are roughly neutral, due largely to the negative (cooling) impact of aerosols from these sources. We partition the global LULCC radiative forcing into three major sources: direct modification of land cover (e.g. deforestation), agricultural activities, and fire regime changes. Contributions from deforestation and agriculture are roughly equal in the present day, while changes to wildfire activity impose a small negative forcing globally. In 2100, deforestation activities comprise the majority of the LULCC radiative forcing for all projections except one (Representative Concentration Pathway (RCP) 4.5). This suggests that realistic scenarios of future forest area change are essential for projecting the contribution of LULCC to climate change. However, the commonly used RCP land cover change projections all include decreases in global deforestation rates over the next 85 years. To place an upper bound on the potential

  4. Influence of Ice Particle Surface Roughening on the Global Cloud Radiative Effect

    Science.gov (United States)

    Yi, Bingqi; Yang, Ping; Baum, Bryan A.; LEcuyer, Tristan; Oreopoulos, Lazaros; Mlawer, Eli J.; Heymsfield, Andrew J.; Liou, Kuo-Nan

    2013-01-01

    Ice clouds influence the climate system by changing the radiation budget and large-scale circulation. Therefore, climate models need to have an accurate representation of ice clouds and their radiative effects. In this paper, new broadband parameterizations for ice cloud bulk scattering properties are developed for severely roughened ice particles. The parameterizations are based on a general habit mixture that includes nine habits (droxtals, hollow/solid columns, plates, solid/hollow bullet rosettes, aggregate of solid columns, and small/large aggregates of plates). The scattering properties for these individual habits incorporate recent advances in light-scattering computations. The influence of ice particle surface roughness on the ice cloud radiative effect is determined through simulations with the Fu-Liou and the GCM version of the Rapid Radiative Transfer Model (RRTMG) codes and the National Center for Atmospheric Research Community Atmosphere Model (CAM, version 5.1). The differences in shortwave (SW) and longwave (LW) radiative effect at both the top of the atmosphere and the surface are determined for smooth and severely roughened ice particles. While the influence of particle roughening on the single-scattering properties is negligible in the LW, the results indicate that ice crystal roughness can change the SW forcing locally by more than 10 W m(exp -2) over a range of effective diameters. The global-averaged SW cloud radiative effect due to ice particle surface roughness is estimated to be roughly 1-2 W m(exp -2). The CAM results indicate that ice particle roughening can result in a large regional SW radiative effect and a small but nonnegligible increase in the global LW cloud radiative effect.

  5. The Impact of Desert Dust Aerosol Radiative Forcing on Global and West African Precipitation

    Science.gov (United States)

    Jordan, A.; Zaitchik, B. F.; Gnanadesikan, A.; Dezfuli, A. K.

    2015-12-01

    Desert dust aerosols exert a radiative forcing on the atmosphere, influencing atmospheric temperature structure and modifying radiative fluxes at the top of the atmosphere (TOA) and surface. As dust aerosols perturb radiative fluxes, the atmosphere responds by altering both energy and moisture dynamics, with potentially significant impacts on regional and global precipitation. Global Climate Model (GCM) experiments designed to characterize these processes have yielded a wide range of results, owing to both the complex nature of the system and diverse differences across models. Most model results show a general decrease in global precipitation, but regional results vary. Here, we compare simulations from GFDL's CM2Mc GCM with multiple other model experiments from the literature in order to investigate mechanisms of radiative impact and reasons for GCM differences on a global and regional scale. We focus on West Africa, a region of high interannual rainfall variability that is a source of dust and that neighbors major Sahara Desert dust sources. As such, changes in West African climate due to radiative forcing of desert dust aerosol have serious implications for desertification feedbacks. Our CM2Mc results show net cooling of the planet at TOA and surface, net warming of the atmosphere, and significant increases in precipitation over West Africa during the summer rainy season. These results differ from some previous GCM studies, prompting comparative analysis of desert dust parameters across models. This presentation will offer quantitative analysis of differences in dust aerosol parameters, aerosol optical properties, and overall particle burden across GCMs, and will characterize the contribution of model differences to the uncertainty of forcing and climate response affecting West Africa.

  6. Shortwave and longwave radiative contributions to global warming under increasing CO2.

    Science.gov (United States)

    Donohoe, Aaron; Armour, Kyle C; Pendergrass, Angeline G; Battisti, David S

    2014-11-25

    In response to increasing concentrations of atmospheric CO2, high-end general circulation models (GCMs) simulate an accumulation of energy at the top of the atmosphere not through a reduction in outgoing longwave radiation (OLR)—as one might expect from greenhouse gas forcing—but through an enhancement of net absorbed solar radiation (ASR). A simple linear radiative feedback framework is used to explain this counterintuitive behavior. It is found that the timescale over which OLR returns to its initial value after a CO2 perturbation depends sensitively on the magnitude of shortwave (SW) feedbacks. If SW feedbacks are sufficiently positive, OLR recovers within merely several decades, and any subsequent global energy accumulation is because of enhanced ASR only. In the GCM mean, this OLR recovery timescale is only 20 y because of robust SW water vapor and surface albedo feedbacks. However, a large spread in the net SW feedback across models (because of clouds) produces a range of OLR responses; in those few models with a weak SW feedback, OLR takes centuries to recover, and energy accumulation is dominated by reduced OLR. Observational constraints of radiative feedbacks—from satellite radiation and surface temperature data—suggest an OLR recovery timescale of decades or less, consistent with the majority of GCMs. Altogether, these results suggest that, although greenhouse gas forcing predominantly acts to reduce OLR, the resulting global warming is likely caused by enhanced ASR.

  7. Effects of UVB radiation on net community production in the upper global ocean

    KAUST Repository

    Garcia-Corral, Lara S.

    2016-08-31

    Aim Erosion of the stratospheric ozone layer together with oligotrophication of the subtropical ocean is leading to enhanced exposure to ultraviolet B (UVB) radiation in ocean surface waters. The impact of increased exposure to UVB on planktonic primary producers and heterotrophs is uncertain. Here we test the null hypothesis that net community production (NCP) of plankton communities in surface waters of the tropical and subtropical ocean is not affected by ambient UVB radiation and extend this test to the global ocean, including the polar oceans and the Mediterranean Sea using previous results. Location We conducted experiments with 131 surface communities sampled during a circumnavigation cruise along the tropical and subtropical ocean and combined these results with 89 previous reports encompassing the Atlantic, Pacific, Arctic and Southern Oceans and the Mediterranean Sea. Methods The use of quartz (transparent to UVB radiation) and borosilicate glass materials (opaque to most UVB) for incubations allowed us to compare NCP between communities where UVB is excluded and those receiving natural UVB radiation. Results We found that NCP varies when exposed to natural UVB radiation compared to those where UVB was removed. NCP of autotrophic communities tended to decrease under natural UVB radiation, whereas the NCP of heterotrophic communities tended to increase. However, these variations showed the opposite trend under higher levels of UVB radiation. Main conclusions Our results suggest that earlier estimates of NCP for surface communities, which were hitherto derived using materials blocking UVB radiation were biased, with the direction and magnitude of this bias depending on the metabolic status of the communities and the underwater penetration of UVB radiation.

  8. Greenhouse gases, radiative forcing, global warming potential and waste management – an introduction

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Kjeldsen, Peter; Gentil, Emmanuel

    2009-01-01

    forcing (RF) and global warming potential (GWP). This paper provides a general introduction of the factors that define a GHG and explains the scientific background for estimating RF and GWP, thereby exposing the lay reader to a brief overview of the methods for calculating the effects of GHGs on climate......Management of post-consumer solid waste contributes to emission of greenhouse gases (GHGs) representing about 3% of global anthropogenic GHG emissions. Most GHG reporting initiatives around the world utilize two metrics proposed by the Intergovernmental Panel on Climate Change (IPCC): radiative...

  9. Global-scale coherence modulation of radiation-belt electron loss from plasmaspheric hiss.

    Science.gov (United States)

    Breneman, A W; Halford, A; Millan, R; McCarthy, M; Fennell, J; Sample, J; Woodger, L; Hospodarsky, G; Wygant, J R; Cattell, C A; Goldstein, J; Malaspina, D; Kletzing, C A

    2015-07-09

    Over 40 years ago it was suggested that electron loss in the region of the radiation belts that overlaps with the region of high plasma density called the plasmasphere, within four to five Earth radii, arises largely from interaction with an electromagnetic plasma wave called plasmaspheric hiss. This interaction strongly influences the evolution of the radiation belts during a geomagnetic storm, and over the course of many hours to days helps to return the radiation-belt structure to its 'quiet' pre-storm configuration. Observations have shown that the long-term electron-loss rate is consistent with this theory but the temporal and spatial dynamics of the loss process remain to be directly verified. Here we report simultaneous measurements of structured radiation-belt electron losses and the hiss phenomenon that causes the losses. Losses were observed in the form of bremsstrahlung X-rays generated by hiss-scattered electrons colliding with the Earth's atmosphere after removal from the radiation belts. Our results show that changes of up to an order of magnitude in the dynamics of electron loss arising from hiss occur on timescales as short as one to twenty minutes, in association with modulations in plasma density and magnetic field. Furthermore, these loss dynamics are coherent with hiss dynamics on spatial scales comparable to the size of the plasmasphere. This nearly global-scale coherence was not predicted and may affect the short-term evolution of the radiation belts during active times.

  10. The International Atomic Energy Agency's activities in radiation medicine and cancer: promoting global health through diplomacy.

    Science.gov (United States)

    Deatsch-Kratochvil, Amanda N; Pascual, Thomas Neil; Kesner, Adam; Rosenblatt, Eduardo; Chhem, Rethy K

    2013-02-01

    Global health has been an issue of seemingly low political importance in comparison with issues that have direct bearing on countries' national security. Recently, health has experienced a "political revolution" or a rise in political importance. Today, we face substantial global health challenges, from the spread of infectious disease, gaps in basic maternal and child health care, to the globalization of cancer. A recent estimate states that the "overall lifetime risk of developing cancer (both sexes) is expected to rise from more than one in three to one in two by 2015." These issues pose significant threats to international health security. To successfully combat these grave challenges, the international community must embrace and engage in global health diplomacy, defined by scholars Thomas Novotny and Vicanne Adams as a political activity aimed at improving global health, while at the same time maintaining and strengthening international relations. The IAEA (International Atomic Energy Agency) is an international organization with a unique mandate to "accelerate and enlarge the contribution of atomic energy to peace, health, and prosperity throughout the world." This article discusses global health diplomacy, reviews the IAEA's program activities in human health by focusing on radiation medicine and cancer, and the peaceful applications of atomic energy within the context of global health diplomacy.

  11. A review of progress towards understanding the transient global mean surface temperature response to radiative perturbation

    Science.gov (United States)

    Yoshimori, Masakazu; Watanabe, Masahiro; Shiogama, Hideo; Oka, Akira; Abe-Ouchi, Ayako; Ohgaito, Rumi; Kamae, Youichi

    2016-12-01

    The correct understanding of the transient response to external radiative perturbation is important for the interpretation of observed climate change, the prediction of near-future climate change, and committed warming under climate stabilization scenarios, as well as the estimation of equilibrium climate sensitivity based on observation data. It has been known for some time that the radiative damping rate per unit of global mean surface temperature increase varies with time, and this inconstancy affects the transient response. Knowledge of the equilibrium response alone is insufficient, but understanding the transient response of the global mean surface temperature has made rapid progress. The recent progress accompanies the relatively new concept of the efficacies of ocean heat uptake and forcing. The ocean heat uptake efficacy associates the temperature response induced by ocean heat uptake with equilibrium temperature response, and the efficacy of forcing compares the temperature response caused by non-CO2 forcing with that by CO2 forcing.

  12. Estimating daily global solar radiation by day of the year in Algeria

    Science.gov (United States)

    Aoun, Nouar; Bouchouicha, Kada

    2017-05-01

    This study presents six empirical models based on the day-of-the-year number for estimating global solar radiation on a horizontal surface. For this case study, 21 years of experimental data sets for 21 cities over the whole Algerian territory are utilized to develop these models for each city and for all of Algeria. In this study, the territory of Algeria was divided into four different climatic zones, i.e., Arid, Semi-arid, Highlands and Mediterranean. The accuracy of the all-Algeria model was tested for each city and for each climate zone. To evaluate the accuracy of the models, the RMSE, rRMSE, MABE, MAPE, and R, which are the most commonly applied statistical parameters, were utilized. The results show that the six developed models provide excellent predictions for global solar radiation for each city and for all-Algeria. Furthermore, the model showing the greatest accuracy is the sine and cosine wave trigonometric model.

  13. Long-term global distribution of earth's shortwave radiation budget at the top of atmosphere

    Directory of Open Access Journals (Sweden)

    N. Hatzianastassiou

    2004-01-01

    Full Text Available The mean monthly shortwave (SW radiation budget at the top of atmosphere (TOA was computed on 2.5° longitude-latitude resolution for the 14-year period from 1984 to 1997, using a radiative transfer model with long-term climatological data from the International Satellite Cloud Climatology Project (ISCCP-D2 supplemented by data from the National Centers for Environmental Prediction – National Center for Atmospheric Research (NCEP-NCAR Global Reanalysis project, and other global data bases such as TIROS Operational Vertical Sounder (TOVS and Global Aerosol Data Set (GADS. The model radiative fluxes at TOA were validated against Earth Radiation Budget Experiment (ERBE S4 scanner satellite data (1985–1989. The model is able to predict the seasonal and geographical variation of SW TOA fluxes. On a mean annual and global basis, the model is in very good agreement with ERBE, overestimating the outgoing SW radiation at TOA (OSR by 0.93 Wm-2 (or by 0.92%, within the ERBE uncertainties. At pixel level, the OSR differences between model and ERBE are mostly within ±10 Wm-2, with ±5 Wm-2 over extended regions, while there exist some geographic areas with differences of up to 40 Wm-2, associated with uncertainties in cloud properties and surface albedo. The 14-year average model results give a planetary albedo equal to 29.6% and a TOA OSR flux of 101.2 Wm-2. A significant linearly decreasing trend in OSR and planetary albedo was found, equal to 2.3 Wm-2 and 0.6% (in absolute values, respectively, over the 14-year period (from January 1984 to December 1997, indicating an increasing solar planetary warming. This planetary SW radiative heating occurs in the tropical and sub-tropical areas (20° S–20° N, with clouds being the most likely cause. The computed global mean OSR anomaly ranges within ±4 Wm-2, with signals from El Niño and La Niña events or Pinatubo eruption, whereas significant negative OSR anomalies, starting from year 1992, are also

  14. Two Loop Radiative Seesaw and X-ray line Dark Matter with Global U(1) Symmetry

    CERN Document Server

    Okada, Hiroshi

    2015-01-01

    We study a two loop induced radiative neutrino model with global $U(1)$ symmetry at 0.1 GeV scale, in which we consider a keV scale of dark matter candidate recently reported by XMN-Newton X-ray observatory using data of various galaxy clusters and Andromeda galaxy. We also discuss the vacuum stability of singly charged bosons, lepton flavor violation processes, and a role of Goldstone boson.

  15. Accounting for radiative forcing from albedo change in future global land-use scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Andrew D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Calvin, Katherine V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Collins, William D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Edmonds, James A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-08-01

    We demonstrate the effectiveness of a new method for quantifying radiative forcing from land use and land cover change (LULCC) within an integrated assessment model, the Global Change Assessment Model (GCAM). The method relies on geographically differentiated estimates of radiative forcing from albedo change associated with major land cover transitions derived from the Community Earth System Model. We find that conversion of 1 km² of woody vegetation (forest and shrublands) to non-woody vegetation (crops and grassland) yields between 0 and –0.71 nW/m² of globally averaged radiative forcing determined by the vegetation characteristics, snow dynamics, and atmospheric radiation environment characteristic within each of 151 regions we consider globally. Across a set of scenarios designed to span a range of potential future LULCC, we find LULCC forcing ranging from –0.06 to –0.29 W/m² by 2070 depending on assumptions regarding future crop yield growth and whether climate policy favors afforestation or bioenergy crops. Inclusion of this previously uncounted forcing in the policy targets driving future climate mitigation efforts leads to changes in fossil fuel emissions on the order of 1.5 PgC/yr by 2070 for a climate forcing limit of 4.5 Wm–2, corresponding to a 12–67 % change in fossil fuel emissions depending on the scenario. Scenarios with significant afforestation must compensate for albedo-induced warming through additional emissions reductions, and scenarios with significant deforestation need not mitigate as aggressively due to albedo-induced cooling. In all scenarios considered, inclusion of albedo forcing in policy targets increases forest and shrub cover globally.

  16. Verification of Global Radiation Forecasts from the Ensemble Prediction System at DMI

    DEFF Research Database (Denmark)

    Lundholm, Sisse Camilla

    consumption of the house and the amount of available solar energy. In order to make the most of this solar heating unit, accurate forecasts of the available solar radiation are esstential. However, because of its sensitivity to local meteorological conditions, the solar radiation received at the surface......To comply with an increasing demand for sustainable energy sources, a solar heating unit is being developed at the Technical University of Denmark. To make optimal use — environmentally and economically —, this heating unit is equipped with an intelligent control system using forecasts of the heat...... of the Earth can be highly fluctuating and challenging to forecast accurately. To comply with the accuracy requirements to forecasts of both global, direct, and diffuse radiation, the uncertainty of these forecasts is of interest. Forecast uncertainties can become accessible by running an ensemble of forecasts...

  17. Simple new methods to estimate global solar radiation based on meteorological data in Egypt

    Science.gov (United States)

    El-Metwally, Mossad

    2004-01-01

    Three simple methods to estimate global solar radiation are proposed in addition to (Solar Energy 63 (1998) 147). All were tested seasonally and at different sky conditions at seven locations in Egypt. The methods use ground-based measurements of maximum and minimum temperature, daily mean of cloud cover and extraterrestrial global radiation. Average of root mean square differences (RMSD) for a comparison between observed and estimated global radiation for all locations tested was around 10% for the new methods and 13% for Supit-Van Kappel method. The coefficient of determination R2 is higher for the new methods for all tested locations. Better results were obtained when applying the new methods to different seasons. The differences in root mean square error (RMSE) between the new methods and Ångstrom-Prescott method that is based on sunshine duration data were less than 1.0 MJ m -2 day -1 at all sites. On the whole, the performance statistics demonstrate that the new methods are better when compared by Ångstrom-Prescott method.

  18. Current global and Korean issues in radiation safety of nuclear medicine procedures.

    Science.gov (United States)

    Song, H C

    2016-06-01

    In recent years, the management of patient doses in medical imaging has evolved as concern about radiation exposure has increased. Efforts and techniques to reduce radiation doses are focussed not only on the basis of patient safety, but also on the fundamentals of justification and optimisation in cooperation with international organisations such as the International Commission on Radiological Protection, the International Atomic Energy Agency, and the World Health Organization. The Image Gently campaign in children and Image Wisely campaign in adults to lower radiation doses have been initiated in the USA. The European Association of Nuclear Medicine paediatric dosage card, North American consensus guidelines, and Nuclear Medicine Global Initiative have recommended the activities of radiopharmaceuticals that should be administered in children. Diagnostic reference levels (DRLs), developed predominantly in Europe, may be an important tool to manage patient doses. In Korea, overexposure to radiation, even from the use of medical imaging, has become a public issue, particularly since the accident at the Fukushima nuclear power plant. As a result, the Korean Nuclear Safety and Security Commission revised the technical standards for radiation safety management in medical fields. In parallel, DRLs for nuclear medicine procedures have been collected on a nationwide scale. Notice of total effective dose from positron emission tomography-computed tomography for cancer screening has been mandatory since mid-November 2014.

  19. EDITORIAL: The Earth radiation balance as driver of the global hydrological cycle

    Science.gov (United States)

    Wild, Martin; Liepert, Beate

    2010-06-01

    Variations in the intensity of the global hydrological cycle can have far-reaching effects on living conditions on our planet. While climate change discussions often revolve around possible consequences of future temperature changes, the adaptation to changes in the hydrological cycle may pose a bigger challenge to societies and ecosystems. Floods and droughts are already today amongst the most damaging natural hazards, with floods being globally the most significant disaster type in terms of loss of human life (Jonkman 2005). From an economic perspective, changes in the hydrological cycle can impose great pressures and damages on a variety of industrial sectors, such as water management, urban planning, agricultural production and tourism. Despite their obvious environmental and societal importance, our understanding of the causes and magnitude of the variations of the hydrological cycle is still unsatisfactory (e.g., Ramanathan et al 2001, Ohmura and Wild 2002, Allen and Ingram 2002, Allan 2007, Wild et al 2008, Liepert and Previdi 2009). The link between radiation balance and hydrological cycle Globally, precipitation can be approximated by surface evaporation, since the variability of the atmospheric moisture storage is negligible. This is the case because the fluxes are an order of magnitude larger than the atmospheric storage (423 x 1012 m3 year-1 versus 13 x 1012 m3 according to Baumgartner and Reichel (1975)), the latter being determined by temperature (Clausius-Clapeyron). Hence the residence time of evaporated water in the atmosphere is not more than a few days, before it condenses and falls back to Earth in the form of precipitation. Any change in the globally averaged surface evaporation therefore implies an equivalent change in precipitation, and thus in the intensity of the global hydrological cycle. The process of evaporation requires energy, which it obtains from the surface radiation balance (also known as surface net radiation), composed of the

  20. Radiation Transfer Calculations and Assessment of Global Warming by CO2

    Directory of Open Access Journals (Sweden)

    Hermann Harde

    2017-01-01

    Full Text Available We present detailed line-by-line radiation transfer calculations, which were performed under different atmospheric conditions for the most important greenhouse gases water vapor, carbon dioxide, methane, and ozone. Particularly cloud effects, surface temperature variations, and humidity changes as well as molecular lineshape effects are investigated to examine their specific influence on some basic climatologic parameters like the radiative forcing, the long wave absorptivity, and back-radiation as a function of an increasing CO2 concentration in the atmosphere. These calculations are used to assess the CO2 global warming by means of an advanced two-layer climate model and to disclose some larger discrepancies in calculating the climate sensitivity. Including solar and cloud effects as well as all relevant feedback processes our simulations give an equilibrium climate sensitivity of CS = 0.7°C (temperature increase at doubled CO2 and a solar sensitivity of SS = 0.17°C (at 0.1% increase of the total solar irradiance. Then CO2 contributes 40% and the Sun 60% to global warming over the last century.

  1. Temperature-based estimation of global solar radiation using soft computing methodologies

    Science.gov (United States)

    Mohammadi, Kasra; Shamshirband, Shahaboddin; Danesh, Amir Seyed; Abdullah, Mohd Shahidan; Zamani, Mazdak

    2016-07-01

    Precise knowledge of solar radiation is indeed essential in different technological and scientific applications of solar energy. Temperature-based estimation of global solar radiation would be appealing owing to broad availability of measured air temperatures. In this study, the potentials of soft computing techniques are evaluated to estimate daily horizontal global solar radiation (DHGSR) from measured maximum, minimum, and average air temperatures ( T max, T min, and T avg) in an Iranian city. For this purpose, a comparative evaluation between three methodologies of adaptive neuro-fuzzy inference system (ANFIS), radial basis function support vector regression (SVR-rbf), and polynomial basis function support vector regression (SVR-poly) is performed. Five combinations of T max, T min, and T avg are served as inputs to develop ANFIS, SVR-rbf, and SVR-poly models. The attained results show that all ANFIS, SVR-rbf, and SVR-poly models provide favorable accuracy. Based upon all techniques, the higher accuracies are achieved by models (5) using T max- T min and T max as inputs. According to the statistical results, SVR-rbf outperforms SVR-poly and ANFIS. For SVR-rbf (5), the mean absolute bias error, root mean square error, and correlation coefficient are 1.1931 MJ/m2, 2.0716 MJ/m2, and 0.9380, respectively. The survey results approve that SVR-rbf can be used efficiently to estimate DHGSR from air temperatures.

  2. Strategy to use the Terra Aerosol Information to Derive the Global Aerosol Radiative Forcing of Climate

    Science.gov (United States)

    Kaufman, Yoram J.; Tanre, Didier; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Terra will derive the aerosol optical thickness and properties. The aerosol properties can be used to distinguish between natural and human-made aerosol. In the polar orbit Terra will measure aerosol only once a day, around 10:30 am. How will we use this information to study the global radiative impacts of aerosol on climate? We shall present a strategy to address this problem. It includes the following steps: - From the Terra aerosol optical thickness and size distribution model we derive the effect of aerosol on reflection of solar radiation at the top of the atmosphere. In a sensitivity study we show that the effect of aerosol on solar fluxes can be derived 10 times more accurately from the MODIS data than derivation of the optical thickness itself. Applications to data over several regions will be given. - Using 1/2 million AERONET global data of aerosol spectral optical thickness we show that the aerosol optical thickness and properties during the Terra 10:30 pass are equivalent to the daily average. Due to the aerosol lifetime of several days measurements at this time of the day are enough to assess the daily impact of aerosol on radiation. - Aerosol impact on the top of the atmosphere is only part of the climate question. The INDOEX experiment showed that addressing the impact of aerosol on climate, requires also measurements of the aerosol forcing at the surface. This can be done by a combination of measurements of MODIS and AERONET data.

  3. Effect of ice-albedo feedback on global sensitivity in a one-dimensional radiative-convective climate model

    Science.gov (United States)

    Wang, W.-C.; Stone, P. H.

    1980-01-01

    The feedback between the ice albedo and temperature is included in a one-dimensional radiative-convective climate model. The effect of this feedback on global sensitivity to changes in solar constant is studied for the current climate conditions. This ice-albedo feedback amplifies global sensitivity by 26 and 39%, respectively, for assumptions of fixed cloud altitude and fixed cloud temperature. The global sensitivity is not affected significantly if the latitudinal variations of mean solar zenith angle and cloud cover are included in the global model. The differences in global sensitivity between one-dimensional radiative-convective models and energy balance models are examined. It is shown that the models are in close agreement when the same feedback mechanisms are included. The one-dimensional radiative-convective model with ice-albedo feedback included is used to compute the equilibrium ice line as a function of solar constant.

  4. Performance assessment of different day-of-the-year-based models for estimating global solar radiation - Case study: Egypt

    Science.gov (United States)

    Hassan, Gasser E.; Youssef, M. Elsayed; Ali, Mohamed A.; Mohamed, Zahraa E.; Shehata, Ali I.

    2016-11-01

    Different models are introduced to predict the daily global solar radiation in different locations but there is no specific model based on the day of the year is proposed for many locations around the world. In this study, more than 20 years of measured data for daily global solar radiation on a horizontal surface are used to develop and validate seven models to estimate the daily global solar radiation by day of the year for ten cities around Egypt as a case study. Moreover, the generalization capability for the best models is examined all over the country. The regression analysis is employed to calculate the coefficients of different suggested models. The statistical indicators namely, RMSE, MABE, MAPE, r and R2 are calculated to evaluate the performance of the developed models. Based on the validation with the available data, the results show that the hybrid sine and cosine wave model and 4th order polynomial model have the best performance among other suggested models. Consequently, these two models coupled with suitable coefficients can be used for estimating the daily global solar radiation on a horizontal surface for each city, and also for all the locations around the studied region. It is believed that the established models in this work are applicable and significant for quick estimation for the average daily global solar radiation on a horizontal surface with higher accuracy. The values of global solar radiation generated by this approach can be utilized in the design and estimation of the performance of different solar applications.

  5. Quantitative assessment of global lung inflammation following radiation therapy using FDG PET/CT: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Abdulla, Sarah; Salavati, Ali; Saboury, Babak; Torigian, Drew A. [University of Pennsylvania, and Hospital of the University of Pennsylvania, Department of Radiology, Perelman School of Medicine, Philadelphia, PA (United States); Basu, Sandip [Bhabha Atomic Research Center, Tata Memorial Center Annexe, Radiation Medicine Center, Bombay (India); Alavi, Abass [University of Pennsylvania, and Hospital of the University of Pennsylvania, Department of Radiology, Perelman School of Medicine, Philadelphia, PA (United States); Hospital of the University of Pennsylvania, Department of Radiology, Division of Nuclear Medicine, Philadelphia, PA (United States)

    2014-02-15

    Radiation pneumonitis is the most severe dose-limiting complication in patients receiving thoracic radiation therapy. The aim of this study was to quantify global lung inflammation following radiation therapy using FDG PET/CT. We studied 20 subjects with stage III non-small-cell lung carcinoma who had undergone FDG PET/CT imaging before and after radiation therapy. On all PET/CT studies, the sectional lung volume (sLV) of each lung was calculated from each slice by multiplying the lung area by slice thickness. The sectional lung glycolysis (sLG) was calculated by multiplying the sLV and the lung sectional mean standardized uptake value (sSUVmean) on each slice passing through the lung. The lung volume (LV) was calculated by adding all sLVs from the lung, and the global lung glycolysis (GLG) was calculated by adding all sLGs from the lung. Finally, the lung SUVmean was calculated by dividing the GLG by the LV. The amount of inflammation in the lung parenchyma directly receiving radiation therapy was calculated by subtracting tumor measurements from GLG. In the lung directly receiving radiation therapy, the lung parenchyma SUVmean and global lung parenchymal glycolysis were significantly increased following therapy. In the contralateral lung (internal control), no significant changes were observed in lung SUVmean or GLG following radiation therapy. Global lung parenchymal glycolysis and lung parenchymal SUVmean may serve as potentially useful biomarkers to quantify lung inflammation on FDG PET/CT following thoracic radiation therapy. (orig.)

  6. A global modeling study on carbonaceous aerosol microphysical characteristics and radiative effects

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2010-08-01

    Full Text Available Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, indirect and semi-direct aerosol effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative effects.

    Our best estimate for net direct and indirect aerosol radiative flux change between 1750 and 2000 is −0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative flux change can vary between −0.32 to −0.75 W/m2 depending on these carbonaceous particle properties at emission. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Absorption of black carbon aerosols is amplified by sulfate and nitrate coatings and, even more strongly, by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative fluxeswhen sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to a reduction in positive radiative flux.

  7. A global modeling study on carbonaceous aerosol microphysical characteristics and radiative forcing

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2010-02-01

    Full Text Available Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, cloud-indirect and semi-direct forcing effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative forcing.

    Our best estimate for net direct and indirect aerosol radiative forcing between 1750 and 2000 is −0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative forcing can vary between −0.32 to −0.75 W/m2 depending on these carbonaceous particle properties at emission. Assuming that sulfates, nitrates and secondary organics form a coating around a black carbon core, rather than forming a uniformly mixed particle, changes the overall net aerosol radiative forcing from negative to positive. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Black carbon absorption is amplified by sulfate and nitrate coatings, but even more strongly by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative forcing when sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to climate benefits.

  8. Diffuse radiation increases global ecosystem-level water-use efficiency

    Science.gov (United States)

    Moffat, A. M.; Reichstein, M.; Cescatti, A.; Knohl, A.; Zaehle, S.

    2012-12-01

    Current environmental changes lead not only to rising atmospheric CO2 levels and air temperature but also to changes in air pollution and thus the light quality of the solar radiation reaching the land-surface. While rising CO2 levels are thought to enhance photosynthesis and closure of stomata, thus leading to relative water savings, the effect of diffuse radiation on transpiration by plants is less clear. It has been speculated that the stimulation of photosynthesis by increased levels of diffuse light may be counteracted by higher transpiration and consequently water depletion and drought stress. Ultimately, in water co-limited systems, the overall effect of diffuse radiation will depend on the sensitivity of canopy transpiration versus photosynthesis to diffuse light, i.e. whether water-use efficiency changes with relative levels of diffuse light. Our study shows that water-use efficiency increases significantly with higher fractions of diffuse light. It uses the ecosystem-atmosphere gas-exchange observations obtained with the eddy covariance method at 29 flux tower sites. In contrast to previous global studies, the analysis is based directly on measurements of diffuse radiation. Its effect on water-use efficiency was derived by analyzing the multivariate response of carbon and water fluxes to radiation and air humidity using a purely empirical approach based on artificial neural networks. We infer that per unit change of diffuse fraction the water-use efficiency increases up to 40% depending on diffuse fraction levels and ecosystem type. Hence, in regions with increasing diffuse radiation positive effects on primary production are expected even under conditions where water is co-limiting productivity.

  9. Global solar radiation: comparison of satellite-based climatology with station records

    Science.gov (United States)

    Skalak, Petr; Zahradnicek, Pavel; Stepanek, Petr; Farda, Ales

    2016-04-01

    We analyze surface incoming shortwave radiation (SIS) from the SARAH dataset prepared by the EUMETSAT Climate Monitoring Satellite Applications Facility from satellite observations of the visible channels of the MVIRI and SEVIRI instruments onboard the geostationary Meteosat satellites. The satellite SIS data are evaluated within the period 1984-2014 on various time scales: from individual months and years to long-term climate means. The validation is performed using the ground measurements of global solar radiation (GLBR) carried out on 11 meteorological stations of the Czech Hydrometeorological Institute in the Czech Republic with at least 30 years long data series. Our aim is to explore whether the SIS data could potentially serve as an alternative source of information on GLBR outside of a relatively sparse network of meteorological stations recording GLBR. Acknowledgement: Supported by the Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Program I (NPU I), grant number LO1415.

  10. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    Energy Technology Data Exchange (ETDEWEB)

    Patara, Lavinia [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel (Germany); Vichi, Marcello; Masina, Simona [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia (INGV), Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Fogli, Pier Giuseppe [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Manzini, Elisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    2012-10-15

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall {approx}0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  11. Unraveling the global microRNAome responses to ionizing radiation in human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Mykyta V Sokolov

    Full Text Available MicroRNAs (miRNA comprise a group of short ribonucleic acid molecules implicated in regulation of key biological processes and functions at the post-transcriptional level. Ionizing radiation (IR causes DNA damage and generally triggers cellular stress response. However, the role of miRNAs in IR-induced response in human embryonic stem cells (hESC has not been defined yet. Here, by using system biology approaches, we show for the first time, that miRNAome undergoes global alterations in hESC (H1 and H9 lines after IR. Interrogation of expression levels of 1,090 miRNA species in irradiated hESC showed statistically significant changes in 54 genes following 1 Gy of X-ray exposures; global miRNAome alterations were found to be highly temporally and cell line--dependent in hESC. Time-course studies showed that the 16 hr miRNAome radiation response of hESC is much more robust compared to 2 hr-response signature (only eight genes, and may be involved in regulating the cell cycle. Quantitative real-time PCR performed on some miRNA species confirms the robustness of our miRNA microarray platform. Positive regulation of differentiation-, cell cycle-, ion transport- and endomembrane system-related processes were predicted to be negatively affected by miRNAome changes in irradiated hESC. Our findings reveal a fundamental role of miRNAome in modulating the radiation response, and identify novel molecular targets of radiation in hESC.

  12. Global structure of Robinson-Trautman radiative space-times with cosmological constant

    CERN Document Server

    Bicák, J

    1997-01-01

    Robinson-Trautman radiative space-times of Petrov type II with a non-vanishing cosmological constant Lambda and mass parameter m>0 are studied using analytical methods. They are shown to approach the corresponding spherically symmetric Schwarzschild-de Sitter or Schwarzschild-anti-de Sitter solution at large retarded times. Their global structure is analyzed, and it is demonstrated that the smoothness of the extension of the metrics across the horizon, as compared with the case Lambda=0, is increased for Lambda>0 and decreased for Lambda0 exhibit explicitly the cosmic no-hair conjecture under the presence of gravitational waves.

  13. Radiative processes of a static atom interacting with a quantum scalar field in global monopole spacetime

    Science.gov (United States)

    Cai, Huabing; Ren, Zhongzhou

    2017-09-01

    We investigate the rate of change of energy for a static two-level atom interacting with a massless quantum scalar field in global monopole spacetime and separately calculate the contributions of thermal fluctuations and radiation reaction. We discuss two different kinds of atom-field interactions separately. The behaviors of the atomic transition rates are analyzed in different circumstances such as near distance and big solid angle deficit. Moreover, we compare the results with those in Minkowski spacetime so as to reveal the effects of the global monopole. In general, as the atom-monopole distance increases, the transition rates oscillate around the results in Minkowski spacetime and the amplitude of oscillation gradually decreases. The oscillation is more severe for larger solid angle deficit. Our works suggest that the transition rates can profoundly change with different atom-field interactions and different types of scalar field.

  14. Correlation between Increases of the Annual Global Solar Radiation and the Ground Albedo Solar Radiation due to Desertification—A Possible Factor Contributing to Climatic Change

    Directory of Open Access Journals (Sweden)

    Emanuele Calabrò

    2016-12-01

    Full Text Available Background: This study investigates the connection between annual global solar radiation and ground albedo solar radiation due to desertification in line with previous research on the correlation between climatic changes and desertification. Methods: A simulation study was performed using an algorithm formulated by the authors and the typical albedo coefficient values of forested ground, green grass and desert sand. Results: It is shown that changing the albedo coefficients from values corresponding to forested ground or green grass to values corresponding to the desert sand causes a significant increase in the annual global solar radiation acquired at different latitudes, leading one to hypothesize a mechanism of reduction of convective overturning and precipitation decreases due to desertification. Conclusion: In this scenario, modifications of local and global climate can be connected to changes of ground solar albedo induced by desertification.

  15. A satellite view of the direct effect of aerosols on solar radiation at global scale

    Science.gov (United States)

    Hatzianastassiou, Nikolaos; Papadimas, Christos D.; Matsoukas, Christos; Fotiadi, Aggeliki; Benas, Nikolaos; Vardavas, Ilias

    2016-04-01

    Aerosols are a key parameter for better understanding and predicting current and future climate change. They are determining, apart from clouds, patterns of solar radiation through scattering and absorption processes. Especially, under cloud-free skies, aerosols are the major modulator of the solar radiation budget of the Earth-atmosphere system. Although significant improvement has been made as to better understanding the direct radiative effect (DRE) of aerosols, there is still a need for further improvement in our knowledge of the DRE spatial and temporal patterns, in particular with respect to extended spatial and temporal coverage of relevant information. In an ongoing rapidly evolving era of great satellite-based achievements, concerning the knowledge of solar radiation budget and its modulators, and with the great progress in obtaining significant information on key aerosol optical properties needed for modeling DRE, it is a great challenge to use all this new aerosol information and to see what is the new acquired scientific knowledge. The objective of this study is to obtain an improved view of global aerosol DRE effects using contemporary accurate data for the important atmospheric and surface parameters determining the solar radiation budget, with emphasis to state of the art aerosol data. Thus, a synergy is made of different datasets providing the necessary input data and of a detailed spectral radiative transfer model (RTM) to compute spectral globally distributed aerosol DREs. Emphasis is given on using highly accurate and well-tested aerosol optical properties. Spectral information on aerosol optical depth (AOD) is taken from retrieved products of the MODerate resolution Imaging Spectroradiometer (MODIS) instrument, while similar information is taken from MODIS for the aerosol asymmetry parameter (AP) over ocean. Information from MODIS is also taken for the aerosol single scattering albedo (SSA). All this information comes from the latest Collection

  16. An Algorithm to Determine the Optimum Tilt Angle of a Solar Panel from Global Horizontal Solar Radiation

    Directory of Open Access Journals (Sweden)

    Emanuele Calabrò

    2013-01-01

    Full Text Available This paper proposes an algorithm to calculate the optimum tilt angle of solar panels by means of global horizontal solar radiation data, provided from Earth-based meteorological stations. This mathematical modeling is based on the maximization of the theoretical expression of the global solar irradiation impinging on an inclined surface, with respect to the slope and orientation of the panel and to the solar hour angle. A set of transcendent equations resulted, whose solutions give the optimum tilt and orientation of a solar panel. A simulation was carried out using global horizontal solar radiation data from the European Solar Radiation Atlas and some empirical models of diffuse solar radiation. The optimum tilt angle resulted was related to latitude by a linear regression with significant correlation coefficients. The standard error of the mean values resulted increased significantly with latitude, suggesting that unreliable values can be provided at high latitudes.

  17. Means and Trends in Solar Radiation: Results From Two Global Data Sets and Effects on Estimated Net Primary Production

    Science.gov (United States)

    Hicke, J. A.

    2005-12-01

    Downwelling surface solar radiation is an important factor driving plant productivity, and clouds and aerosols are major factors responsible for interannual variability in downwelling radiation. Global ecosystem models require spatially extensive data sets that vary interannually to capture effects that potentially drive changes in ecosystem function. Representative global solar radiation data sets include National Centers for Environmental Prediction (NCEP) reanalyses and Goddard Institute for Space Studies (GISS) calculations that included satellite observations of cloud properties. The CASA light-use efficiency model, which utilizes solar radiation and satellite-derived vegetation information, was run with the two solar radiation data sets to explore how differences affect estimated net primary production (NPP). Mean global NCEP solar radiation exceeded that from GISS by 16%, likely as a result of lower cloudiness within the NCEP reanalyses compared to satellite observations. Neither data set resulted in a significant trend in growing season radiation over the study period (1984-2000). Locally, relative differences were up to 40% in the mean and 10% in the trend of solar radiation and NPP, and varied in sign across the globe.

  18. Numerical Weather Prediction (NWP) and hybrid ARMA/ANN model to predict global radiation

    CERN Document Server

    Voyant, Cyril; Paoli, Christophe; Nivet, Marie Laure

    2012-01-01

    We propose in this paper an original technique to predict global radiation using a hybrid ARMA/ANN model and data issued from a numerical weather prediction model (ALADIN). We particularly look at the Multi-Layer Perceptron. After optimizing our architecture with ALADIN and endogenous data previously made stationary and using an innovative pre-input layer selection method, we combined it to an ARMA model from a rule based on the analysis of hourly data series. This model has been used to forecast the hourly global radiation for five places in Mediterranean area. Our technique outperforms classical models for all the places. The nRMSE for our hybrid model ANN/ARMA is 14.9% compared to 26.2% for the na\\"ive persistence predictor. Note that in the stand alone ANN case the nRMSE is 18.4%. Finally, in order to discuss the reliability of the forecaster outputs, a complementary study concerning the confidence interval of each prediction is proposed

  19. Establishing a Global Radiation Oncology Collaboration in Education (GRaCE): Objectives and priorities.

    Science.gov (United States)

    Turner, Sandra; Eriksen, Jesper G; Trotter, Theresa; Verfaillie, Christine; Benstead, Kim; Giuliani, Meredith; Poortmans, Philip; Holt, Tanya; Brennan, Sean; Pötter, Richard

    2015-10-01

    Representatives from countries and regions world-wide who have implemented modern competency-based radiation- or clinical oncology curricula for training medical specialists, met to determine the feasibility and value of an ongoing international collaboration. In this forum, educational leaders from the ESTRO School, encompassing many European countries adopting the ESTRO Core Curriculum, and clinician educators from Canada, Denmark, the United Kingdom, Australia and New Zealand considered the training and educational arrangements within their jurisdictions, identifying similarities and challenges between programs. Common areas of educational interest and need were defined, which included development of new competency statements and assessment tools, and the application of the latter. The group concluded that such an international cooperation, which might expand to include others with similar goals, would provide a valuable vehicle to ensure training program currency, through sharing of resources and expertise, and enhance high quality radiation oncology education. Potential projects for the Global Radiation Oncology Collaboration in Education (GRaCE) were agreed upon, as was a strategy designed to maintain momentum. This paper describes the rationale for establishing this collaboration, presents a comparative view of training in the jurisdictions represented, and reports early goals and priorities.

  20. Accuracy tests of radiation schemes used in hot Jupiter Global Circulation Models

    CERN Document Server

    Amundsen, David Skålid; Tremblin, Pascal; Manners, James; Hayek, Wolfgang; Mayne, N J; Acreman, David M

    2014-01-01

    The treatment of radiation transport in global circulation models (GCMs) is crucial to correctly describe Earth and exoplanet atmospheric dynamics processes. The two-stream approximation and correlated-$k$ method are currently state-of-the-art approximations applied in both Earth and hot Jupiter GCM radiation schemes to facilitate rapid calculation of fluxes and heating rates. Their accuracy have been tested extensively for Earth-like conditions, but verification of the methods' applicability to hot Jupiter-like conditions is lacking in the literature. We are adapting the UK Met Office GCM, the Unified Model (UM), for the study of hot Jupiters, and present in this work the adaptation of the Edwards-Slingo radiation scheme based on the two-stream approximation and the correlated-$k$ method. We discuss the calculation of absorption coefficients from high temperature line lists and highlight the large uncertainty in the pressure-broadened line widths. We compare fluxes and heating rates obtained with our adapted...

  1. A surrogate-based metaheuristic global search method for beam angle selection in radiation treatment planning

    Science.gov (United States)

    Zhang, H. H.; Gao, S.; Chen, W.; Shi, L.; D'Souza, W. D.; Meyer, R. R.

    2013-03-01

    An important element of radiation treatment planning for cancer therapy is the selection of beam angles (out of all possible coplanar and non-coplanar angles in relation to the patient) in order to maximize the delivery of radiation to the tumor site and minimize radiation damage to nearby organs-at-risk. This category of combinatorial optimization problem is particularly difficult because direct evaluation of the quality of treatment corresponding to any proposed selection of beams requires the solution of a large-scale dose optimization problem involving many thousands of variables that represent doses delivered to volume elements (voxels) in the patient. However, if the quality of angle sets can be accurately estimated without expensive computation, a large number of angle sets can be considered, increasing the likelihood of identifying a very high quality set. Using a computationally efficient surrogate beam set evaluation procedure based on single-beam data extracted from plans employing equally-spaced beams (eplans), we have developed a global search metaheuristic process based on the nested partitions framework for this combinatorial optimization problem. The surrogate scoring mechanism allows us to assess thousands of beam set samples within a clinically acceptable time frame. Tests on difficult clinical cases demonstrate that the beam sets obtained via our method are of superior quality.

  2. Modeling the Impact of Vegetation Structure on Canopy Radiative Transfer for a Global Vegetation Dynamic Model

    Science.gov (United States)

    Ni-Meister, W.; Kiang, N.; Yang, W.

    2007-12-01

    The transmission of light through plant canopies results in vertical profiles of light intensity that affect the photosynthetic activity and gas exchange of plants, their competition for light, and the canopy energy balance. The accurate representation of the canopy light profile is then important for predicting ecological dynamics. The study presents a simple canopy radiative transfer scheme to characterize the impact of the horizontal and vertical vegetation structure heterogeneity on light profiles. Actual vertical foliage profile and a clumping factor which are functions of tree geometry, size and density and foliage density are used to characterize the vertical and horizontal vegetation structure heterogeneity. The simple scheme is evaluated using the ground and airborne lidar data collected in deciduous and coniferous forests and was also compared with the more complex Geometric Optical and Radiative Transfer (GORT) model and the two-stream scheme currently being used to describe light interactions with vegetation canopy in most GCMs. The simple modeled PAR profiles match well with the ground data, lidar and full GORT model prediction, it performs much better than the simple Beer's&plaw used in two stream scheme. This scheme will have the same computation cost as the current scheme being used in GCMs, but provides better photosynthesis, radiative fluxes and surface albedo estimates, thus is suitable for a global vegetation dynamic model embedded in GCMs.

  3. Improved sea-ice radiative processes in a global coupled climate model

    Institute of Scientific and Technical Information of China (English)

    LIU Jiping; ZHANG Zhanhai; WU Huiding

    2005-01-01

    The NASA Goddard Institute for Space Studies (GISS) coupled global climate model was used to investigate the sensitivity of sea ice to improved representations of sea-ice radiative processes: (1) a more sophisticated surface albedo scheme and (2) the penetration of solar radiation in sea ice. The results show that the large-scale sea-ice conditions are very sensitive to the aforementioned parameterizations. Although the more sophisticated surface albedo scheme produces a more realistic seasonal cycle of the surface albedo as compared with the baseline simulation, the resulting higher albedo relative to the baseline simulation generates much more and thicker ice in the arctic. The penetration of solar radiation in sea-ice itself tends to reduce the ice cover and thickness in the entire arctic and the western antarctic, and increase the ice cover and thickness in the eastern antarctic. The combination of (1) and (2) significantly improves the simulations of the average ice thickness and its spatial distribution in the arctic. The atmospheric responses associated with sea-ice changes were also discussed. While improvements are seen, particularly of the ice thickness distribution, there are still some unrealistic aspects that will require further improvements to the sea-ice component.

  4. Contribution of solar radiation and geomagnetic activity to global structure of 27-day variation of ionosphere

    Science.gov (United States)

    Yao, Yibin; Zhai, Changzhi; Kong, Jian; Liu, Lei

    2017-04-01

    Twenty-seven-day variation caused by solar rotation is one of the main periodic effects of solar radiation influence on the ionosphere, and there have been many studies on this periodicity using peak electron density N_{mF2} and solar radio flux index F10.7. In this paper, the global electron content (GEC) and observation of Solar EUV Monitor (SEM) represent the whole ionosphere and solar EUV flux, respectively, to investigate the 27-day variation. The 27-day period components of indices (GEC_{27}, SEM_{27}, F10.7_{27}, Ap_{27}) are obtained using Chebyshev band-pass filter. The comparison of regression results indicates that the index SEM has higher coherence than F10.7 with 27-day variation of the ionosphere. The regression coefficients of SEM_{27 } varied from 0.6 to 1.4 and the coefficients of Ap_{27} varied from - 0.6 to 0.3, which suggests that EUV radiation seasonal variations are the primary driver for the 27-day variations of the ionosphere for most periods. TEC map grid points on three meridians where IGS stations are dense are selected for regression, and the results show that the contribution of solar EUV radiation is positive at all geomagnetic latitudes and larger than geomagnetic activity in most latitudes. The contribution of geomagnetic activity is negative at high geomagnetic latitude, increasing with decreasing geomagnetic latitudes, and positive at low geomagnetic latitudes. The global structure of 27-day variation of ionosphere is presented and demonstrates that there are two zonal anomaly regions along with the geomagnetic latitudes lines and two peaks in the north of Southeast Asia and the Middle Pacific where TEC_{27} magnitude values are notably larger than elsewhere along zonal anomaly regions.

  5. Global Solar radiation in Spain from Satellite Images; Radiacion Solar Global en la Espana Peninsular a partir de images de satelite

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Santigosa, L.; Mora Lopez, L.; Sidrach de Cardona Ortin, M.; Navarro Fernandez, A. A.; Varela conde, M.; Cruz Echeandia, M. de la

    2003-07-01

    In the context of the present work a series of algorithms of calculation of the solar radiation from satellite images has been developed. These models, have been applied to three years of images of the Meteosat satellite and the results of the treatment have been extrapolated to long term. For the development of the models of solar radiation registered in ground stations have been used, corresponding all of them to localities of peninsular Spain and the Balearic ones. The maximum periods of data available have been used, supposing in most of the cases periods of between 6 and 9 years. From the results has a year type of images of global solar radiation on horizontal surface. The original resolution of the image of 7x7 km in the study latitudes, has been revaluate to 5x5 km. This supposes to have a value of the typical radiation for every day of the year, each 5x5 km in the study territory. This information, supposes an important advance as far as the knowledge of the space distribution of the radiation solar,impossible to reach about alternative methods. Doubtlessly, the precision of the provided values is not comparable with pyranometric measures in a concrete localise, but it provides a very valid indicator in places in which, it not had previous information. In addition to the radiation maps, tables of the global solar radiation have been prepared on different inclinations, from the global radiation on horizontal surface calculated for every day of the year and in each pixel of the image. (Author) 24 refs.

  6. CONTRIBUTION TO THE STUDY OF GLOBAL RADIATION AND INSOLATION IN THE MATO GROSSO DE GOIÁS MICROREGION CONTRIBUIÇÃO AO ESTUDO DA RADIAÇÃO GLOBAL E DA INSOLAÇÃO NA MICRO-REGIÃO DO MATO GROSSO DE GOIÁS

    Directory of Open Access Journals (Sweden)

    Engler José Vidigal Lobato

    2007-09-01

    Full Text Available

    This work studies the month average of daily global solar radiation, daily relative global solar radiation, daily sunshine duration and daily relative sunshine duration, for the conditions in Goiânia county and surrounding counties, Goiás — Brazil (latitude: 16°41'S, longitude: 49°17’W GRW, and altitude: 680.00m. It's observed that: a global solar radiation is maximum in October and minimum in July; b relative global solar radiation is maximum in August and minimum in November; c sunshine duration is maximum in June and minimum in November; d relative sunshine duration is maximum in June and minimum in November. Correlation between the month average of daily relative global solar radiation and of daily sunshine duration allowed to conclude the linear equation: Kg = Ka (0.49 n/N, where the letters mean: Kg = daily global radiation (ly/day; Ka = daily solar radiation on the top of atmosphere (ly/day; n = daily duration of sunshine (hr/day; N = daily maximum duration of sunshine (hr/day. The methodology adopted was the one proposed by PRESCOTT (1940 and PENMAM (1948, as cited by BLACK et alii (1954, in order to estimate parameters ";a"; and “b”, in the equation Kg/Ka = a + b (n/N, which correlates the sunshine ratio (n/N to the relative solar, radiation (Kg/Ka by linear regression analysis. The equation found showed a correlation coefficient which was equal to 0.95 with significance at 0.1% probability level.

    O presente trabalho analisa as médias mensais de radiação solar global diária, radiação solar global relativa diária, insolação diária do Mato Grosso de Goiás. Os dados utilizados foram obtidos na Estação Evaporimétrica de lª classe, Modelo DNAEE — CPRM, localizada na Escola de Agronomia — UFG, latitude: 16°41'S, longitude 49°17'W GRW, altitude 680,00m e na Estação do Centro

  7. Impact of Changes in Diffuse Radiation on the Global Land Carbon Sink, 1901-2100

    Science.gov (United States)

    Mercado, L.; Bellouin, N.; Sitch, S.; Boucher, O.; Huntingford, C.; Wild, M.; Cox, P. M.

    2009-04-01

    Recent observational and theoretical studies have shown that changes in surface radiation that lead to increasing diffuse surface irradiance, enhance plant photosynthesis (Gu et al., 2003, Niyogi et al., 2004, Oliveira et al., 2007, Roderick et al., 2001). Solar radiation reaching the land surface has changed over the industrial era due to aerosols emitted from volcanoes and various anthropogenic sources (Kvalevag and Myhre, 2007). Such changes in total surface radiation are accompanied by changes in direct and diffuse surface solar radiation. Current global climate-carbon models do include the effects of changes in total surface radiation on the land biosphere but neglect the positive effects of increasing diffuse fraction on plant photosynthesis. In this study we estimate for the first time, the impact of variations in diffuse fraction on the land carbon sink using a global model (Mercado et al., 2007) modified to account for the effects of variations in both direct and diffuse radiation on canopy photosynthesis. We use meteorological forcing from the Climate Research Unit Data set. Additionally short wave and photosynthetic active radiation are reconstructed from the Hadley centre climate model, which accounts for the scattering and absorption of light by tropospheric and stratospheric aerosols and change in cloud properties due to indirect aerosol effects. References Gu L.H., Baldocchi D.D., Wofsy S.C., Munger J.W., Michalsky J.J., Urbanski S.P. & Boden T.A. (2003) Response of a deciduous forest to the Mount Pinatubo eruption: Enhanced photosynthesis. Science, 299, 2035-2038. M. M. Kvalevag and G. Myhre, J. Clim. 20, 4874 (2007). Mercado L.M., Huntingford C., Gash J.H.C., Cox P.M. & Jogireddy V. (2007) Improving the representation of radiation interception and photosynthesis for climate model applications. Tellus Series B-Chemical and Physical Meteorology, 59, 553-565. Niyogi D., Chang H.I., Saxena V.K., Holt T., Alapaty K., Booker F., Chen F., Davis K

  8. The global land shortwave cryosphere radiative effect during the MODIS era

    Science.gov (United States)

    Singh, D.; Flanner, M. G.; Perket, J.

    2015-11-01

    The shortwave cryosphere radiative effect (CrRE) is the instantaneous influence of snow and ice cover on Earth's top-of-atmosphere (TOA) solar energy budget. Here, we apply measurements from the MODerate resolution Imaging Spectroradiometer (MODIS), combined with microwave retrievals of snow presence and radiative kernels produced from four different models, to derive CrRE over global land during 2001-2013. We estimate global annual-mean land CrRE during this period of -2.6 W m-2, with variations from -2.2 to -3.0 W m-2 resulting from use of different kernels and variations of -2.4 to -2.6 W m-2 resulting from different algorithmic determinations of snow presence and surface albedo. Slightly more than half of the global land CrRE originates from perennial snow on Antarctica, whereas the majority of the northern hemispheric effect originates from seasonal snow. Consequently, the northern hemispheric land CrRE peaks at -6.0 W m-2 in April, whereas the southern hemispheric effect more closely follows the austral insolation cycle, peaking at -9.0 W m-2 in December. Mountain glaciers resolved in 0.05° MODIS data contribute about -0.037 W m-2 (1.4 %) of the global effect, with the majority (94 %) of this contribution originating from the Himalayas. Interannual trends in the global annual-mean land CrRE are not statistically significant during the MODIS era, but trends are positive (less negative) over large areas of northern Asia, especially during spring, and slightly negative over Antarctica, possibly due to increased snowfall. During a common overlap period of 2001-2008, our MODIS estimates of the northern hemispheric land CrRE are about 18 % smaller (less negative) than previous estimates derived from coarse-resolution AVHRR data, though interannual variations are well correlated (r = 0.78), indicating that these data are useful in determining longer-term trends in land CrRE.

  9. Interannual variation of global net radiation flux as measured from space

    Science.gov (United States)

    Zhu, Ping; Wild, Martin; Ruymbeke, Michel; Thuillier, Gérard; Meftah, Mustapha; Karatekin, Ozgur

    2016-06-01

    The global net radiation flux (NRF) in and out of the climate system at the top of the atmosphere (TOA) varies at interannual time scales, reflecting the complexity of the processes responsible for attaining global energy equilibrium. These processes are investigated in this study using the previously unexplored data acquired by a bolometric type sensor installed in the PICARD microsatellite. The obtained anomalies in the NRF (PICARD-NRF) are compared to the global NRF changes at the TOA measured by the Clouds and Earth's Radiant Energy System mission (CERES-NRF). The interanual PICARD-NRF is strongly correlated with the matching period CERES-NRF; the bootstrapped correlation at the 95%(+0.85 and +0.97) confidence intervals is +0.93. Consistency in the interannual variability in the NRF derived by two completely independent measurement systems enhances confidence in the estimated magnitude of these variations. To reveal the possible drivers of the NRF interannual variability, the NRF values were compared with the multivariate El Niño-Southern Oscillation index.

  10. Accuracy tests of radiation schemes used in hot Jupiter global circulation models

    Science.gov (United States)

    Amundsen, David S.; Baraffe, Isabelle; Tremblin, Pascal; Manners, James; Hayek, Wolfgang; Mayne, Nathan J.; Acreman, David M.

    2014-04-01

    The treatment of radiation transport in global circulation models (GCMs) is crucial for correctly describing Earth and exoplanet atmospheric dynamics processes. The two-stream approximation and correlated-k method are currently state-of-the-art approximations applied in both Earth and hot Jupiter GCM radiation schemes to facilitate the rapid calculation of fluxes and heating rates. Their accuracy have been tested extensively for Earth-like conditions, but verification of the methods' applicability to hot Jupiter-like conditions is lacking in the literature. We are adapting the UK Met Office GCM, the Unified Model (UM), for the study of hot Jupiters, and present in this work the adaptation of the Edwards-Slingo radiation scheme based on the two-stream approximation and the correlated-k method. We discuss the calculation of absorption coefficients from high-temperature line lists and highlight the large uncertainty in the pressure-broadened line widths. We compare fluxes and heating rates obtained with our adapted scheme to more accurate discrete ordinate (DO) line-by-line (LbL) calculations ignoring scattering effects. We find that, in most cases, errors stay below 10% for both heating rates and fluxes using ~10 k-coefficients in each band and a diffusivity factor D = 1.66. The two-stream approximation and the correlated-k method both contribute non-negligibly to the total error. We also find that using band-averaged absorption coefficients, which have previously been used in radiative-hydrodynamical simulations of a hot Jupiter, may yield errors of ~100%, and should thus be used with caution.

  11. Power spectral density and scaling exponent of high frequency global solar radiation sequences

    Science.gov (United States)

    Calif, Rudy; Schmitt, François G.; Huang, Yongxiang

    2013-04-01

    The part of the solar power production from photovlotaïcs systems is constantly increasing in the electric grids. Solar energy converter devices such as photovoltaic cells are very sensitive to instantaneous solar radiation fluctuations. Thus rapid variation of solar radiation due to changes in the local meteorological condition can induce large amplitude fluctuations of the produced electrical power and reduce the overall efficiency of the system. When large amount of photovoltaic electricity is send into a weak or small electricity network such as island network, the electric grid security can be in jeopardy due to these power fluctuations. The integration of this energy in the electrical network remains a major challenge, due to the high variability of solar radiation in time and space. To palliate these difficulties, it is essential to identify the characteristic of these fluctuations in order to anticipate the eventuality of power shortage or power surge. The objective of this study is to present an approach based on Empirical Mode Decomposition (EMD) and Hilbert-Huang Transform (HHT) to highlight the scaling properties of global solar irradiance data G(t). The scale of invariance is detected on this dataset using the Empirical Mode Decomposition in association with arbitrary-order Hilbert spectral analysis, a generalization of (HHT) or Hilbert Spectral Analysis (HSA). The first step is the EMD, consists in decomposing the normalized global solar radiation data G'(t) into several Intrinsic Mode Functions (IMF) Ci(t) without giving an a priori basis. Consequently, the normalized original solar radiation sequence G'(t) can be written as a sum of Ci(t) with a residual rn. From all IMF modes, a joint PDF P(f,A) of locally and instantaneous frequency f and amplitude A, is estimated. To characterize the scaling behavior in amplitude-frequency space, an arbitrary-order Hilbert marginal spectrum is defined to: Iq(f) = 0 P (f,A)A dA (1) with q × 0 In case of scale

  12. Biomass burning emissions estimated with a global fire assimilation system based on observed fire radiative power

    Directory of Open Access Journals (Sweden)

    J. W. Kaiser

    2011-07-01

    Full Text Available The Global Fire Assimilation System (GFASv1.0 calculates biomass burning emissions by assimilating Fire Radiative Power (FRP observations from the MODIS instruments onboard the Terra and Aqua satellites. It corrects for gaps in the observations, which are mostly due to cloud cover, and filters spurious FRP observations of volcanoes, gas flares and other industrial activity. The combustion rate is subsequently calculated with land cover-specific conversion factors. Emission factors for 40 gas-phase and aerosol trace species have been compiled from a literature survey. The corresponding daily emissions have been calculated on a global 0.5° × 0.5° grid from 2003 to the present. General consistency with the Global Fire Emission Database version 3.1 (GFED3.1 within its accuracy is achieved while maintaining the advantages of an FRP-based approach: GFASv1.0 makes use of the quantitative information on the combustion rate that is contained in the observations, and it detects fires in real time at high spatial and temporal resolution. GFASv1.0 indicates omission errors in GFED3.1 due to undetected small fires. It also exhibits slightly longer fire seasons in South America and North Africa and a slightly shorter fire season in Southeast Asia. GFASv1.0 has already been used for atmospheric reactive gas simulations in an independent study, which found good agreement with atmospheric observations. We have performed simulations of the atmospheric aerosol distribution with and without the assimilation of MODIS aerosol optical depth (AOD. They indicate that the emissions of particulate matter need to be boosted with a factor of 2–4 to reproduce the global distribution of organic matter and black carbon. This discrepancy is also evident in the comparison of previously published top-down and bottom-up estimates. For the time being, a global enhancement of the particulate matter emissions by 3.4 is recommended. Validation with independent AOD and PM10

  13. Assessment and added value estimation of an ensemble approach with a focus on global radiation forecasts

    CERN Document Server

    Bouallegue, Zied Ben

    2015-01-01

    The assessment of the high-resolution ensemble weather prediction system COSMO-DE-EPS is achieved with the perspective of using it for renewable energy applications. The performance of the ensemble forecast is explored focusing on global radiation, the main weather variable affecting solar power production, and on quantile forecasts, key probabilistic products for the energy sector. First, the ability of the ensemble system to capture and resolve the observation variability is assessed. Secondly, the potential benefit of the ensemble forecasting strategy compared to a single forecast approach is quantitatively estimated. A new metric called ensemble added value is proposed, aiming at a fair comparison of an ensemble forecast with a single forecast, when optimized to the users' needs. Hourly mean forecasts are verified against pyranometer measurements over verification periods covering 2013. The results show in particular that the added value of the ensemble approach is season-dependent and increases with the ...

  14. ARTIFICIAL NEURAL NETWORK AND WAVELET DECOMPOSITION IN THE FORECAST OF GLOBAL HORIZONTAL SOLAR RADIATION

    Directory of Open Access Journals (Sweden)

    Luiz Albino Teixeira Júnior

    2015-04-01

    Full Text Available This paper proposes a method (denoted by WD-ANN that combines the Artificial Neural Networks (ANN and the Wavelet Decomposition (WD to generate short-term global horizontal solar radiation forecasting, which is an essential information for evaluating the electrical power generated from the conversion of solar energy into electrical energy. The WD-ANN method consists of two basic steps: firstly, it is performed the decomposition of level p of the time series of interest, generating p + 1 wavelet orthonormal components; secondly, the p + 1 wavelet orthonormal components (generated in the step 1 are inserted simultaneously into an ANN in order to generate short-term forecasting. The results showed that the proposed method (WD-ANN improved substantially the performance over the (traditional ANN method.

  15. Tectonic collision and uplift of Wallacea triggered the global songbird radiation

    Science.gov (United States)

    Moyle, Robert G.; Oliveros, Carl H.; Andersen, Michael J.; Hosner, Peter A.; Benz, Brett W.; Manthey, Joseph D.; Travers, Scott L.; Brown, Rafe M.; Faircloth, Brant C.

    2016-08-01

    Songbirds (oscine passerines) are the most species-rich and cosmopolitan bird group, comprising almost half of global avian diversity. Songbirds originated in Australia, but the evolutionary trajectory from a single species in an isolated continent to worldwide proliferation is poorly understood. Here, we combine the first comprehensive genome-scale DNA sequence data set for songbirds, fossil-based time calibrations, and geologically informed biogeographic reconstructions to provide a well-supported evolutionary hypothesis for the group. We show that songbird diversification began in the Oligocene, but accelerated in the early Miocene, at approximately half the age of most previous estimates. This burst of diversification occurred coincident with extensive island formation in Wallacea, which provided the first dispersal corridor out of Australia, and resulted in independent waves of songbird expansion through Asia to the rest of the globe. Our results reconcile songbird evolution with Earth history and link a major radiation of terrestrial biodiversity to early diversification within an isolated Australian continent.

  16. Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation

    KAUST Repository

    Lee, Kyu Tae

    2016-12-06

    Emerging classes ofconcentrator photovoltaic (CPV) modules reach efficiencies that are far greater than those of even the highest performance flat-plate PV technologies, with architectures that have the potential to provide the lowest cost of energy in locations with high direct normal irradiance (DNI). A disadvantage is their inability to effectively use diffuse sunlight, thereby constraining widespread geographic deployment and limiting performance even under the most favorable DNI conditions. This study introduces a module design that integrates capabilities in flat-plate PV directly with the most sophisticated CPV technologies, for capture of both direct and diffuse sunlight, thereby achieving efficiency in PV conversion of the global solar radiation. Specific examples of this scheme exploit commodity silicon (Si) cells integrated with two different CPV module designs, where they capture light that is not efficiently directed by the concentrator optics onto large-scale arrays of miniature multijunction (MJ) solar cells that use advanced III-V semiconductor technologies. In this CPV scheme (

  17. Time series modeling and large scale global solar radiation forecasting from geostationary satellites data

    CERN Document Server

    Voyant, Cyril; Muselli, Marc; Paoli, Christophe; Nivet, Marie Laure

    2014-01-01

    When a territory is poorly instrumented, geostationary satellites data can be useful to predict global solar radiation. In this paper, we use geostationary satellites data to generate 2-D time series of solar radiation for the next hour. The results presented in this paper relate to a particular territory, the Corsica Island, but as data used are available for the entire surface of the globe, our method can be easily exploited to another place. Indeed 2-D hourly time series are extracted from the HelioClim-3 surface solar irradiation database treated by the Heliosat-2 model. Each point of the map have been used as training data and inputs of artificial neural networks (ANN) and as inputs for two persistence models (scaled or not). Comparisons between these models and clear sky estimations were proceeded to evaluate the performances. We found a normalized root mean square error (nRMSE) close to 16.5% for the two best predictors (scaled persistence and ANN) equivalent to 35-45% related to ground measurements. F...

  18. Global Harmonization of Quality Assurance Naming Conventions in Radiation Therapy Clinical Trials

    Energy Technology Data Exchange (ETDEWEB)

    Melidis, Christos, E-mail: christos.melidis@eortc.be [European Organization for the Research and Treatment of Cancer–Radiation Oncology Group (EORTC-ROG), Radiation Therapy Quality Assurance (RTQA), Brussels (Belgium); Bosch, Walther R. [Washington University, representing Advanced Technology Consortium, Radiation Oncology, St. Louis, Missouri (United States); Izewska, Joanna [Dosimetry Laboratory, International Atomic Energy Agency, Vienna (Austria); Fidarova, Elena; Zubizarreta, Eduardo [Applied Radiation Biology and Radiotherapy Section, International Atomic Energy Agency, Vienna (Austria); Ulin, Kenneth [Department of Radiation Oncology, University of Massachusetts Medical School, Representing Quality Assurance Review Center, Worcester, Massachusetts (United States); Ishikura, Satoshi [Department of Radiation Oncology, Juntendo University, Representing Japan Clinical Oncology Group, RTQA, Tokyo (Japan); Followill, David [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Representing Radiological Physics Center, RTQA, Houston, Texas (United States); Galvin, James [Department of Radiation Oncology, Thomas Jefferson University, Representing Radiation Therapy Oncology Group, RTQA, Philadelphia, Pennsylvania (United States); Haworth, Annette [Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, representing TransTasman Radiation Oncology Group (TROG) Cancer Research, Newcastle (Australia); Besuijen, Deidre [North West Cancer Centre, Representing TROG Cancer Research, Newcastle (Australia); Clark, Clark H. [Department of Medical Physics, St. Luke' s Cancer Centre, Royal Surrey County Hospital, Guildford, Surrey and National Physical Laboratory, Teddington, Middlesex, representing Radiation Therapy Trials Quality Assurance (RTTQA) (United Kingdom); Miles, Elizabeth; Aird, Edwin [Mount Vernon Cancer Centre, Northwood, Middlesex representing RTTQA (United Kingdom); and others

    2014-12-01

    Purpose: To review the various radiation therapy quality assurance (RTQA) procedures used by the Global Clinical Trials RTQA Harmonization Group (GHG) steering committee members and present the harmonized RTQA naming conventions by amalgamating procedures with similar objectives. Methods and Materials: A survey of the GHG steering committee members' RTQA procedures, their goals, and naming conventions was conducted. The RTQA procedures were classified as baseline, preaccrual, and prospective/retrospective data capture and analysis. After all the procedures were accumulated and described, extensive discussions took place to come to harmonized RTQA procedures and names. Results: The RTQA procedures implemented within a trial by the GHG steering committee members vary in quantity, timing, name, and compliance criteria. The procedures of each member are based on perceived chances of noncompliance, so that the quality of radiation therapy planning and treatment does not negatively influence the trial measured outcomes. A comparison of these procedures demonstrated similarities among the goals of the various methods, but the naming given to each differed. After thorough discussions, the GHG steering committee members amalgamated the 27 RTQA procedures to 10 harmonized ones with corresponding names: facility questionnaire, beam output audit, benchmark case, dummy run, complex treatment dosimetry check, virtual phantom, individual case review, review of patients' treatment records, and protocol compliance and dosimetry site visit. Conclusions: Harmonized RTQA harmonized naming conventions, which can be used in all future clinical trials involving radiation therapy, have been established. Harmonized procedures will facilitate future intergroup trial collaboration and help to ensure comparable RTQA between international trials, which enables meta-analyses and reduces RTQA workload for intergroup studies.

  19. An Algorithm to Determine the Optimum Tilt Angle of a Solar Panel from Global Horizontal Solar Radiation

    OpenAIRE

    Emanuele Calabrò

    2013-01-01

    This paper proposes an algorithm to calculate the optimum tilt angle of solar panels by means of global horizontal solar radiation data, provided from Earth-based meteorological stations. This mathematical modeling is based on the maximization of the theoretical expression of the global solar irradiation impinging on an inclined surface, with respect to the slope and orientation of the panel and to the solar hour angle. A set of transcendent equations resulted, whose solutions give the optimu...

  20. Studying the physical basis of global warming: thermal effects of the interaction between radiation and matter and greenhouse effect

    Energy Technology Data Exchange (ETDEWEB)

    Besson, Ugo; De Ambrosis, Anna; Mascheretti, Paolo [Department of Physics ' A Volta' , University of Pavia, Via A Bassi 6, 27100 Pavia (Italy)], E-mail: ugo.besson@unipv.it, E-mail: anna.deambrosisvigna@unipv.it

    2010-03-15

    We present a teaching module dealing with the thermal effects of interaction between radiation and matter, the infrared emission of bodies and the greenhouse effect devoted to university level and teacher education. The module stresses the dependence of the optical properties of materials (transparency, absorptivity and emissivity) on radiation frequency, as a result of interaction between matter and radiation. Multiple experiences are suggested to favour a progressive construction of knowledge on the physical aspects necessary to understand the greenhouse effect and global warming. Some results obtained with university students are briefly reported.

  1. Solar Simulated Ultraviolet Radiation Induces Global Histone Hypoacetylation in Human Keratinocytes.

    Directory of Open Access Journals (Sweden)

    Xiaoru Zhang

    Full Text Available Ultraviolet radiation (UVR from sunlight is the primary effector of skin DNA damage. Chromatin remodeling and histone post-translational modification (PTM are critical factors in repairing DNA damage and maintaining genomic integrity, however, the dynamic changes of histone marks in response to solar UVR are not well characterized. Here we report global changes in histone PTMs induced by solar simulated UVR (ssUVR. A decrease in lysine acetylation of histones H3 and H4, particularly at positions of H3 lysine 9, lysine 56, H4 lysine 5, and lysine 16, was found in human keratinocytes exposed to ssUVR. These acetylation changes were highly associated with ssUVR in a dose-dependent and time-specific manner. Interestingly, H4K16ac, a mark that is crucial for higher order chromatin structure, exhibited a persistent reduction by ssUVR that was transmitted through multiple cell divisions. In addition, the enzymatic activities of histone acetyltransferases were significantly reduced in irradiated cells, which may account for decreased global acetylation. Moreover, depletion of histone deacetylase SIRT1 in keratinocytes rescued ssUVR-induced H4K16 hypoacetylation. These results indicate that ssUVR affects both HDAC and HAT activities, leading to reduced histone acetylation.

  2. Multiple global radiations in tadpole shrimps challenge the concept of ‘living fossils’

    Directory of Open Access Journals (Sweden)

    Thomas C. Mathers

    2013-04-01

    Full Text Available ‘Living fossils’, a phrase first coined by Darwin, are defined as species with limited recent diversification and high morphological stasis over long periods of evolutionary time. Morphological stasis, however, can potentially lead to diversification rates being underestimated. Notostraca, or tadpole shrimps, is an ancient, globally distributed order of branchiopod crustaceans regarded as ‘living fossils’ because their rich fossil record dates back to the early Devonian and their morphology is highly conserved. Recent phylogenetic reconstructions have shown a strong biogeographic signal, suggesting diversification due to continental breakup, and widespread cryptic speciation. However, morphological conservatism makes it difficult to place fossil taxa in a phylogenetic context. Here we reveal for the first time the timing and tempo of tadpole shrimp diversification by inferring a robust multilocus phylogeny of Branchiopoda and applying Bayesian divergence dating techniques using reliable fossil calibrations external to Notostraca. Our results suggest at least two bouts of global radiation in Notostraca, one of them recent, so questioning the validity of the ‘living fossils’ concept in groups where cryptic speciation is widespread.

  3. Solar Simulated Ultraviolet Radiation Induces Global Histone Hypoacetylation in Human Keratinocytes.

    Science.gov (United States)

    Zhang, Xiaoru; Kluz, Thomas; Gesumaria, Lisa; Matsui, Mary S; Costa, Max; Sun, Hong

    2016-01-01

    Ultraviolet radiation (UVR) from sunlight is the primary effector of skin DNA damage. Chromatin remodeling and histone post-translational modification (PTM) are critical factors in repairing DNA damage and maintaining genomic integrity, however, the dynamic changes of histone marks in response to solar UVR are not well characterized. Here we report global changes in histone PTMs induced by solar simulated UVR (ssUVR). A decrease in lysine acetylation of histones H3 and H4, particularly at positions of H3 lysine 9, lysine 56, H4 lysine 5, and lysine 16, was found in human keratinocytes exposed to ssUVR. These acetylation changes were highly associated with ssUVR in a dose-dependent and time-specific manner. Interestingly, H4K16ac, a mark that is crucial for higher order chromatin structure, exhibited a persistent reduction by ssUVR that was transmitted through multiple cell divisions. In addition, the enzymatic activities of histone acetyltransferases were significantly reduced in irradiated cells, which may account for decreased global acetylation. Moreover, depletion of histone deacetylase SIRT1 in keratinocytes rescued ssUVR-induced H4K16 hypoacetylation. These results indicate that ssUVR affects both HDAC and HAT activities, leading to reduced histone acetylation.

  4. Brightening of the global cloud field by nitric acid and the associated radiative forcing

    Directory of Open Access Journals (Sweden)

    R. Makkonen

    2012-08-01

    Full Text Available Clouds cool Earth's climate by reflecting 20% of the incoming solar energy, while also trapping part of the outgoing radiation. The effect of human activities on clouds is poorly understood, but the present-day anthropogenic cooling via changes of cloud albedo and lifetime could be of the same order as warming from anthropogenic addition in CO2. Soluble trace gases can increase water condensation to particles, possibly leading to activation of smaller aerosols and more numerous cloud droplets. We have studied the effect of nitric acid on the aerosol indirect effect with the global aerosol-climate model ECHAM5.5-HAM2. Including the nitric acid effect in the model increases cloud droplet number concentrations globally by 7%. The nitric acid contribution to the present-day cloud albedo effect was found to be −0.32 W m−2 and to the total indirect effect −0.46 W m−2. The contribution to the cloud albedo effect is shown to increase to −0.37 W m−2 by the year 2100, if considering only the reductions in available cloud condensation nuclei. Overall, the effect of nitric acid can play a large part in aerosol cooling during the following decades with decreasing SO2 emissions and increasing NOx and greenhouse gases.

  5. Daily global fire radiative power fields estimation from one or two MODIS instruments

    Directory of Open Access Journals (Sweden)

    S. Remy

    2014-08-01

    Full Text Available Fires are important emitters of aerosol and trace gases and as such need to be taken into account in any atmospheric composition modeling enterprise. One method to estimate these emissions is to convert Fire Radiative Power (FRP analysis to dry matter burnt and emissions of smoke constituents using land cover dependent conversion factors. Inventories like the Global Fire Assimilation System (GFAS follow this approach by calculating daily global smoke emissions from FRP observed by the MODIS instruments on-board of the Terra and Aqua satellites. Observations with different overpass times systematically sample fires at different stages in the strong diurnal fire cycle. For some time periods, observations are available from only one instrument, which leads to a bias in the observed average FRP. We develop a method to correct this bias in daily FRP observations from any Low Earth Orbit (LEO satellite, so that the budget of daily smoke emissions remains independent of the number of satellites from which FRP observations are taken into account. This ensures the possibility of running, e.g., GFAS in case of a default of one of the MODIS instruments. It also enables the extension GFAS to 2000–2002 and the inclusion of FRP observations from upcoming satellite missions. The correction combines linear and non-linear regressions and uses an adaptive regionalization algorithm. It removes the bias in daily average FRP observations from Terra and Aqua nearly entirely. Errors are larger for Terra than for Aqua, are generally relatively small at a global scale, but can be important at a local scale. The correction algorithm is applied to Terra observations from 25 February 2000 to 31 December 2002, when Aqua observations were not available. The database of fire emissions GFASv1.0 is extended correspondingly.

  6. Lightning driven inner radiation belt energy deposition into the atmosphere: regional and global estimates

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2005-12-01

    Full Text Available In this study we examine energetic electron precipitation fluxes driven by lightning, in order to determine the global distribution of energy deposited into the middle atmosphere. Previous studies using lightning-driven precipitation burst rates have estimated losses from the inner radiation belts. In order to confirm the reliability of those rates and the validity of the conclusions drawn from those studies, we have analyzed New Zealand data to test our global understanding of troposphere to magnetosphere coupling. We examine about 10000h of AbsPAL recordings made from 17 April 2003 through to 26 June 2004, and analyze subionospheric very-low frequency (VLF perturbations observed on transmissions from VLF transmitters in Hawaii (NPM and western Australia (NWC. These observations are compared with those previously reported from the Antarctic Peninsula. The perturbation rates observed in the New Zealand data are consistent with those predicted from the global distribution of the lightning sources, once the different experimental configurations are taken into account. Using lightning current distributions rather than VLF perturbation observations we revise previous estimates of typical precipitation bursts at L~2.3 to a mean precipitation energy flux of ~1×10-3 ergs cm-2s-1. The precipitation of energetic electrons by these bursts in the range L=1.9-3.5 will lead to a mean rate of energy deposited into the atmosphere of 3×10-4 ergs cm-2min-1, spatially varying from a low of zero above some ocean regions to highs of ~3-6×10-3 ergs cm-2min-1 above North America and its conjugate region.

  7. A Kalman Filter-Based Method for Reconstructing GMS-5 Global Solar Radiation by Introduction of In Situ Data

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2013-06-01

    Full Text Available Solar radiation is an important input for various land-surface energy balance models. Global solar radiation data retrieved from the Japanese Geostationary Meteorological Satellite 5 (GMS-5/Visible and Infrared Spin Scan Radiometer (VISSR has been widely used in recent years. However, due to the impact of clouds, aerosols, solar elevation angle and bidirectional reflection, spatial or temporal deficiencies often exist in solar radiation datasets that are derived from satellite remote sensing, which can seriously affect the accuracy of application models of land-surface energy balance. The goal of reconstructing radiation data is to simulate the seasonal variation patterns of solar radiation, using various statistical and numerical analysis methods to interpolate the missing observations and optimize the whole time-series dataset. In the current study, a reconstruction method based on data assimilation is proposed. Using a Kalman filter as the assimilation algorithm, the retrieved radiation values are corrected through the continuous introduction of local in-situ global solar radiation (GSR provided by the China Meteorological Data Sharing Service System (Daily radiation dataset_Version 3 which were collected from 122 radiation data collection stations over China. A complete and optimal set of time-series data is ultimately obtained. This method is applied and verified in China’s northern agricultural areas (humid regions, semi-humid regions and semi-arid regions in a warm temperate zone. The results show that the mean value and standard deviation of the reconstructed solar radiation data series are significantly improved, with greater consistency with ground-based observations than the series before reconstruction. The method implemented in this study provides a new solution for the time-series reconstruction of surface energy parameters, which can provide more reliable data for scientific research and regional renewable-energy planning.

  8. Annual evolution of global, direct and diffuse radiation and fractions in tilted surfaces Evolução anual das radiações e fraç��es global, direta e difusa em superfícies inclinadas

    Directory of Open Access Journals (Sweden)

    Adilson P. de Souza

    2012-04-01

    Full Text Available It was evaluated the annual evolution of global, direct and diffuse components of incident solar radiation on tilted surfaces to 12.85, 22.85 and 32.85º, facing north, in Botucatu, state of São Paulo, Brazil. The radiometric fractions were obtained for each component of the radiation in the aforementioned surfaces, through the ratio with the global and top of the atmosphere radiations. Seasonality was evaluated based on monthly averages of daily values. The measures occurred between 04/1998 and 07/2001 at 22.85º; 08/2001 and 02/2003 at 12.85º; and from 03/2003 to 12/2007 at 32.85º, with concomitant measures in the horizontal surface (reference. The levels of global and direct radiation on tilted surfaces were lower in summer and higher in the equinoxes when compared with the horizontal. The diffuse radiation on tilted surfaces was lower in most months, with losses of up to 65%. A trend of increasing differences occurred between horizontal and tilted surfaces with the increase of the angle in all the components and fractions of incident radiation. The annual evolution of rainfall and cloud cover ratio directly affected the atmospheric transmissivity of direct and diffuse components in the region.Avaliou-se a evolução anual das componentes global, direta e difusa da radiação solar incidente em superfícies inclinadas a 12,85; 22,85 e 32,85º, com face voltada ao Norte, em Botucatu-SP. Foram obtidas frações radiométricas para cada componente da radiação nas superfícies supracitadas, através de razões com a radiação global e a do topo da atmosfera. A sazonalidade foi avaliada através das médias mensais dos valores diários. As medidas ocorreram entre 04/1998 e 07/2001, em 22,85º; 08/2001 e 02/2003, em 12,85º; e de 03/2003 a 12/2007, em 32,85º, com medidas concomitantes no plano horizontal (referência. Os níveis das radiações global e direta nos planos inclinados foram inferiores no período de verão e superiores entre os

  9. An Assessment of the Current US Radiation Oncology Workforce: Methodology and Global Results of the American Society for Radiation Oncology 2012 Workforce Study

    Energy Technology Data Exchange (ETDEWEB)

    Vichare, Anushree; Washington, Raynard; Patton, Caroline; Arnone, Anna [ASTRO, Fairfax, Virginia (United States); Olsen, Christine [Massachusetts General Hospital, Boston, Massachusetts, (United States); Fung, Claire Y. [Commonwealth Newburyport Cancer Center, Newburyport, Massachusetts (United States); Hopkins, Shane [William R. Bliss Cancer Center, Ames, Iowa (United States); Pohar, Surjeet, E-mail: spohar@netzero.net [Indiana University Health Cancer Center East, Indiana University, Indianapolis, Indiana (United States)

    2013-12-01

    Purpose: To determine the characteristics, needs, and concerns of the current radiation oncology workforce, evaluate best practices and opportunities for improving quality and safety, and assess what we can predict about the future workforce. Methods and Materials: An online survey was distributed to 35,204 respondents from all segments of the radiation oncology workforce, including radiation oncologists, residents, medical dosimetrists, radiation therapists, medical physicists, nurse practitioners, nurses, physician assistants, and practice managers/administrators. The survey was disseminated by the American Society for Radiation Oncology (ASTRO) together with specialty societies representing other workforce segments. An overview of the methods and global results is presented in this paper. Results: A total of 6765 completed surveys were received, a response rate of 19%, and the final analysis included 5257 respondents. Three-quarters of the radiation oncologists, residents, and physicists who responded were male, in contrast to the other segments in which two-thirds or more were female. The majority of respondents (58%) indicated they were hospital-based, whereas 40% practiced in a free-standing/satellite clinic and 2% in another setting. Among the practices represented in the survey, 21.5% were academic, 25.2% were hospital, and 53.3% were private. A perceived oversupply of professionals relative to demand was reported by the physicist, dosimetrist, and radiation therapist segments. An undersupply was perceived by physician's assistants, nurse practitioners, and nurses. The supply of radiation oncologists and residents was considered balanced. Conclusions: This survey was unique as it attempted to comprehensively assess the radiation oncology workforce by directly surveying each segment. The results suggest there is potential to improve the diversity of the workforce and optimize the supply of the workforce segments. The survey also provides a benchmark for

  10. Simply obtained global radiation, soil temperature and soil moisture in an alley cropping system in semi-arid Kenya

    NARCIS (Netherlands)

    Mungai, D.N.; Stigter, C.J.; Coulson, C.L.; Ng'ang'a, J.K.

    2000-01-01

    Global radiation, soil temperature and soil moisture data were obtained from a 4-6 year old Cassia siamea/maize (CM) alley cropping (or hedgerow intercropping) system, at a semi-arid site at Machakos, Kenya, in the late eighties. With the growing need to explore and manage variations in agro-ecosyst

  11. Global Existence and Asymptotic Behavior of Cylindrically Symmetric Solutions for the 3D Infrarelativistic Model with Radiation

    Science.gov (United States)

    Qin, Yuming; Zhang, Jianlin

    2016-12-01

    In this paper, we establish the global existence, uniqueness and asymptotic behavior of cylindrically symmetric solutions for the 3D infrarelativistic model with radiation in H^i× (H^i)^3× H^i× H^{i+1}(i=1,2,4) . The key point is that the smallness of initial data is not needed.

  12. Using Satellite Observations of Cloud Vertical Distribution to Improve Global Model Estimates of Cloud Radiative Effect on Key Tropospheric Oxidants

    Science.gov (United States)

    Liu, Hongyu; Crawford, James; Ham, Seung-Hee; Zhang, Bo; Kato, Seiji; Voulgarakis, Apostolos; Chen, Gao; Fairlie, Duncan; Duncan, Bryan; Yantosca, Robert

    2017-01-01

    Clouds directly affect tropospheric photochemistry through modification of solar radiation that determines photolysis frequencies. This effect is an important component of global tropospheric chemistry-climate interaction, and its understanding is thus essential for predicting the feedback of climate change on tropospheric chemistry.

  13. Final Technical Report for "Radiative Heating Associated with Tropical Convective Cloud Systems: Its Importance at Meso and Global Scales"

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Courtney

    2012-12-13

    Heating associated with tropical cloud systems drive the global circulation. The overall research objectives of this project were to i) further quantify and understand the importance of heating in tropical convective cloud systems with innovative observational techniques, and ii) use global models to determine the large-scale circulation response to variability in tropical heating profiles, including anvil and cirrus cloud radiative forcing. The innovative observational techniques used a diversity of radar systems to create a climatology of vertical velocities associated with the full tropical convective cloud spectrum along with a dissection of the of the total heating profile of tropical cloud systems into separate components (i.e., the latent, radiative, and eddy sensible heating). These properties were used to validate storm-scale and global climate models (GCMs) and were further used to force two different types of GCMs (one with and one without interactive physics). While radiative heating was shown to account for about 20% of the total heating and did not have a strong direct response on the global circulation, the indirect response was important via its impact on convection, esp. in how radiative heating impacts the tilt of heating associated with the Madden-Julian Oscillation (MJO), a phenomenon that accounts for most tropical intraseasonal variability. This work shows strong promise in determining the sensitivity of climate models and climate processes to heating variations associated with cloud systems.

  14. Global top-down smoke aerosol emissions estimation using satellite fire radiative power measurements

    Directory of Open Access Journals (Sweden)

    C. Ichoku

    2013-10-01

    Full Text Available Biomass burning occurs seasonally in most vegetated parts of the world, consuming large amounts of biomass fuel, generating intense heat energy, and emitting corresponding amounts of smoke plumes that comprise different species of aerosols and trace gases. Accurate estimates of these emissions are required as model inputs to evaluate and forecast smoke plume transport and impacts on air quality, human health, clouds, weather, radiation, and climate. Emissions estimates have long been based on bottom-up approaches that are not only complex, but also fraught with compounding uncertainties. Fortunately, a series of recent studies have revealed that both the rate of biomass consumption and the rate of emission of aerosol particulate matter (PM by open biomass burning are directly proportional to the rate of release of fire radiative energy (FRE, which is fire radiative power (FRP that is measurable from satellite. This direct relationship enables the determination of coefficients of emission (Ce, which can be used to convert FRP or FRE to smoke aerosol emissions in the same manner as emission factors (EFs are used to convert burned biomass to emissions. We have leveraged this relationship to generate the first global 1° × 1° gridded Ce product for smoke aerosol or total particulate matter (TPM emissions using coincident measurements of FRP and aerosol optical thickness (AOT from the Moderate-resolution Imaging Spectro-radiometer (MODIS sensors aboard the Terra and Aqua satellites. This new Fire Energetics and Emissions Research version 1.0 (FEER.v1 Ce product has now been released to the community and can be obtained from http://feer.gsfc.nasa.gov/, along with the corresponding 1-to-1 mapping of their quality assurance (QA flags that will enable the Ce values to be filtered by quality for use in various applications. The regional averages of Ce values for different ecosystem types were found to be in the ranges of: 16–21 g MJ−1 for savanna

  15. Evaluation of Various Methods for Estimating Global Solar Radiation in the Southeastern United States

    Energy Technology Data Exchange (ETDEWEB)

    Woli, Prem; Paz, Joel O.

    2012-05-01

    Global solar radiation Rg is an important input for crop models to simulate crop responses. Because the scarcity of long and continuous records of Rg is a serious limitation in many countries, Rg is estimated using models. For crop-model application, empirical Rg models that use commonly measured meteorological variables, such as temperature and precipitation, are generally preferred. Although a large number of models of this kind exist, few have been evaluated for conditions in the United States. This study evaluated the performances of 16 empirical, temperature- and/or precipitation-based Rg models for the southeastern United States. By taking into account spatial distribution and data availability, 30 locations in the region were selected and their daily weather data spanning eight years obtained. One-half of the data was used for calibrating the models, and the other half was used for evaluation. For each model, location-specific parameter values were estimated through regressions. Models were evaluated for each location using the root-mean-square error and the modeling efficiency as goodness-of-fit measures. Among the models that use temperature or precipitation as the input variable, the Mavromatis model showed the best performance. The piecewise linear regression based Wu et al. model (WP) performed best not only among the models that use both temperature and precipitation but also among the 16 models evaluated, mainly because it has separate relationships for low and high radiation levels. The modeling efficiency of WP was from ~5% to more than 100% greater than those of the other models, depending on models and locations.

  16. Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation

    Science.gov (United States)

    Lee, Kyu-Tae; Yao, Yuan; He, Junwen; Fisher, Brent; Sheng, Xing; Lumb, Matthew; Xu, Lu; Anderson, Mikayla A.; Scheiman, David; Han, Seungyong; Kang, Yongseon; Gumus, Abdurrahman; Bahabry, Rabab R.; Lee, Jung Woo; Paik, Ungyu; Bronstein, Noah D.; Alivisatos, A. Paul; Meitl, Matthew; Burroughs, Scott; Mustafa Hussain, Muhammad; Lee, Jeong Chul; Nuzzo, Ralph G.; Rogers, John A.

    2016-12-01

    Emerging classes of concentrator photovoltaic (CPV) modules reach efficiencies that are far greater than those of even the highest performance flat-plate PV technologies, with architectures that have the potential to provide the lowest cost of energy in locations with high direct normal irradiance (DNI). A disadvantage is their inability to effectively use diffuse sunlight, thereby constraining widespread geographic deployment and limiting performance even under the most favorable DNI conditions. This study introduces a module design that integrates capabilities in flat-plate PV directly with the most sophisticated CPV technologies, for capture of both direct and diffuse sunlight, thereby achieving efficiency in PV conversion of the global solar radiation. Specific examples of this scheme exploit commodity silicon (Si) cells integrated with two different CPV module designs, where they capture light that is not efficiently directed by the concentrator optics onto large-scale arrays of miniature multijunction (MJ) solar cells that use advanced III-V semiconductor technologies. In this CPV+ scheme (“+” denotes the addition of diffuse collector), the Si and MJ cells operate independently on indirect and direct solar radiation, respectively. On-sun experimental studies of CPV+ modules at latitudes of 35.9886° N (Durham, NC), 40.1125° N (Bondville, IL), and 38.9072° N (Washington, DC) show improvements in absolute module efficiencies of between 1.02% and 8.45% over values obtained using otherwise similar CPV modules, depending on weather conditions. These concepts have the potential to expand the geographic reach and improve the cost-effectiveness of the highest efficiency forms of PV power generation.

  17. Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation

    Science.gov (United States)

    Lee, Kyu-Tae; Yao, Yuan; He, Junwen; Fisher, Brent; Sheng, Xing; Lumb, Matthew; Xu, Lu; Anderson, Mikayla A.; Scheiman, David; Han, Seungyong; Kang, Yongseon; Gumus, Abdurrahman; Bahabry, Rabab R.; Lee, Jung Woo; Paik, Ungyu; Bronstein, Noah D.; Alivisatos, A. Paul; Meitl, Matthew; Burroughs, Scott; Hussain, Muhammad Mustafa; Lee, Jeong Chul; Nuzzo, Ralph G.; Rogers, John A.

    2016-01-01

    Emerging classes of concentrator photovoltaic (CPV) modules reach efficiencies that are far greater than those of even the highest performance flat-plate PV technologies, with architectures that have the potential to provide the lowest cost of energy in locations with high direct normal irradiance (DNI). A disadvantage is their inability to effectively use diffuse sunlight, thereby constraining widespread geographic deployment and limiting performance even under the most favorable DNI conditions. This study introduces a module design that integrates capabilities in flat-plate PV directly with the most sophisticated CPV technologies, for capture of both direct and diffuse sunlight, thereby achieving efficiency in PV conversion of the global solar radiation. Specific examples of this scheme exploit commodity silicon (Si) cells integrated with two different CPV module designs, where they capture light that is not efficiently directed by the concentrator optics onto large-scale arrays of miniature multijunction (MJ) solar cells that use advanced III–V semiconductor technologies. In this CPV+ scheme (“+” denotes the addition of diffuse collector), the Si and MJ cells operate independently on indirect and direct solar radiation, respectively. On-sun experimental studies of CPV+ modules at latitudes of 35.9886° N (Durham, NC), 40.1125° N (Bondville, IL), and 38.9072° N (Washington, DC) show improvements in absolute module efficiencies of between 1.02% and 8.45% over values obtained using otherwise similar CPV modules, depending on weather conditions. These concepts have the potential to expand the geographic reach and improve the cost-effectiveness of the highest efficiency forms of PV power generation. PMID:27930331

  18. Space life sciences: structure and dynamics of the global space radiation field at aircraft altitudes.

    Science.gov (United States)

    2003-01-01

    This issue is devoted to research papers on the radiation environment encountered by aircraft crew members and the flying public, both of which are exposed to a higher than average radiation dose. Two types of space radiation are considered: galactic cosmic radiation and solar activity. The papers include reviews on atmospheric ionization radiation, the factors controlling this radiation, the modeling of this radiation, and measurements made on board specific aircraft flights during solar minimum and solar maximum conditions, and during the major solar proton events that occurred in 1989 and 2001.

  19. The assessment of four different correction models applied to the diffuse radiation measured with a shadow ring using global and normal beam radiation measurements for Beer Sheva, Israel

    Energy Technology Data Exchange (ETDEWEB)

    Kudish, Avraham I.; Evseev, Efim G. [Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, E D Bergmann Campus, Beer Sheva 84105 (Israel)

    2008-02-15

    The measurement of the diffuse radiation incident on a horizontal surface, a priori a straightforward task, is fraught with difficulties. It is possible to measure the diffuse radiation by three different techniques: two of which measure it directly and the third indirectly. The most accurate is the indirect one, which is based upon the concurrent measurements of the horizontal global and the normal incidence beam radiation. The disadvantage of this being the relatively expensive tracking system required for measuring the latter. The diffuse radiation can be measured directly with a pyranometer outfitted with either an occulting disk or shadow ring, which prevent the beam radiation from impinging on the pyranometer sensor. The occulting disk can provide accurate measurements of the diffuse radiation but it requires a relatively expensive sun tracking system in the east-west axis. The shadow ring is a stationary device with regard to the east-west axis and blocks the beam radiation component by creating a permanent shadow on the pyranometer sensor. The major disadvantage of the shadow ring is that it also blocks that portion of the diffuse radiation obscured by the shadow ring. This introduces a measurement error that must be corrected to account for that portion of the sky obscured by the shadow band. In addition to this geometric correction factor there is a need to correct for anisotropic sky conditions. Four correction models have been applied to the data for Beer Sheva, Israel and the results have been evaluated both graphically and statistically. An attempt has been made to score the relative performance of the models under different sky conditions. (author)

  20. Variation of radiative forcings and global warming potentials from regional aviation NOx emissions

    Science.gov (United States)

    Skowron, Agnieszka; Lee, David S.; De León, Ruben R.

    2015-03-01

    The response to hemispherical and regional aircraft NOx emissions is explored by using two climate metrics: radiative forcing (RF) and Global Warming Potential (GWP). The global chemistry transport model, MOZART-3 CTM, is applied in this study for a series of incremental aircraft NOx emission integrations to different regions. It was found that the sensitivity of chemical responses per unit emission rate from regional aircraft NOx emissions varies with size of aircraft NOx emission rate and that climate metric values decrease with increasing aircraft NOx emission rates, except for Southeast Asia. Previous work has recognized that aircraft NOx GWPs may vary regionally. However, the way in which these regional GWPs are calculated are critical. Previous studies have added a fixed amount of NOx to different regions. This approach can heavily bias the results of a regional GWP because of the well-established sensitivity of O3 production to background NOx whereby the Ozone Production Efficiency (OPE) is greater at small background NOx. Thus, even a small addition of NOx in a clean-air area can produce a large O3 response. Using this 'fixed addition' method of 0.035 Tg(N) yr-1, results in the greatest effect observed for North Atlantic and Brazil, ∼10.0 mW m-2/Tg(N) yr-1. An alternative 'proportional approach' is also taken that preserves the subtle balance of local NOx-O3-CH4 systems with the existing emission patterns of aircraft and background NOx, whereby a proportional amount of aircraft NOx, 5% (N) yr-1, is added to each region in order to determine the response. This results in the greatest effect observed for North Pacific that with its net NOx RF of 23.7 mW m-2/Tg(N) yr-1 is in contrast with the 'fixed addition' method. For determining regional NOx GWPs, it is argued that the 'proportional' approach gives more representative results. However, a constraint of both approaches is that the regional GWP determined is dependent on the relative global emission pattern

  1. Global Characterization of Biomass-Burning Patterns using Satellite Measurements of Fire Radiative Energy

    Science.gov (United States)

    Ichoku, Charles; Giglio, Louis; Wooster, Martin J.; Remer, Lorraine A.

    2008-01-01

    Remote sensing is the most practical means of measuring energy release from large open-air biomass burning. Satellite measurement of fire radiative energy (FRE) release rate or power (FRP) enables distinction between fires of different strengths. Based on a 1-km resolution fire data acquired globally by the MODerate-resolution Imaging Spectro-radiometer (MODIS) sensor aboard the Terra and Aqua satellites from 2000 to 2006, instanteaneous FRP values ranged between 0.02 MW and 1866 MW, with global daily means ranging between 20 and 40 MW. Regionally, at the Aqua-MODIS afternoon overpass, the mean FRP values for Alaska, Western US, Western Australia, Quebec and the rest of Canada are significantly higher than these global means, with Quebec having the overall highest value of 85 MW. Analysis of regional mean FRP per unit area of land (FRP flux) shows that a peak fire season in certain regions, fires can be responsible for up to 0.2 W/m(sup 2) at peak time of day. Zambia has the highest regional monthly mean FRP flux of approximately 0.045 W/m(sup 2) at peak time of day and season, while the Middle East has the lowest value of approximately 0.0005 W/m(sup 2). A simple scheme based on FRP has been devised to classify fires into five categories, to facilitate fire rating by strength, similar to earthquakes and hurricanes. The scheme uses MODIS measurements of FRP at 1-km resolution as follows: catagory 1 (less than 100 MW), category 2 (100 to less than 500 MW), category 3 (500 to less than 1000 MW), category 4 (1000 to less than 1500 MW), catagory 5 (greater than or equal to 1500 MW). In most regions of the world, over 90% of fires fall into category 1, while only less than 1% fall into each of categories 3 to 5, although these proportions may differ significantly from day to day and by season. The frequency of occurence of the larger fires is region specific, and could not be explained by ecosystem type alone. Time-series analysis of the propertions of higher category

  2. Estimation of Radiative Efficiency of Chemicals with Potentially Significant Global Warming Potential.

    Science.gov (United States)

    Betowski, Don; Bevington, Charles; Allison, Thomas C

    2016-01-19

    Halogenated chemical substances are used in a broad array of applications, and new chemical substances are continually being developed and introduced into commerce. While recent research has considerably increased our understanding of the global warming potentials (GWPs) of multiple individual chemical substances, this research inevitably lags behind the development of new chemical substances. There are currently over 200 substances known to have high GWP. Evaluation of schemes to estimate radiative efficiency (RE) based on computational chemistry are useful where no measured IR spectrum is available. This study assesses the reliability of values of RE calculated using computational chemistry techniques for 235 chemical substances against the best available values. Computed vibrational frequency data is used to estimate RE values using several Pinnock-type models, and reasonable agreement with reported values is found. Significant improvement is obtained through scaling of both vibrational frequencies and intensities. The effect of varying the computational method and basis set used to calculate the frequency data is discussed. It is found that the vibrational intensities have a strong dependence on basis set and are largely responsible for differences in computed RE values.

  3. Sunshine and global solar radiation estimation at different sites in Egypt

    Science.gov (United States)

    El-Metwally, Mossad

    2005-09-01

    A simple non-linear method is proposed for estimating relative sunshine duration based on monthly mean daily maximum and minimum air temperatures and cloud cover fraction at six sites in Egypt, where long-term period (9 15 years) data were recorded. This method gives low errors (mean bias error is about -0.4% and root mean square is about 2.3% for pooled data), so it can be used in case of unavailability of sunshine duration data. Also, a non-linear equation has been proposed at the same sites to estimate monthly mean daily global radiation based on observed and estimated values of relative sunshine duration. This method was compared with linear Ångström Prescott and double linear of Garg Garg equation. These methods were tested seasonally and at different sky conditions (clear, partially cloudy and overcast skies). Also they have been tested against 32 stations dataset, at worldwide sites. The results show that the bias error for the proposed method is low, average values to mean bias error and root mean square error are around 0.1% and 6%, respectively, while they are around 3% and 7% to the other methods at pooled data. Generally, the proposed method preformed better than the others.

  4. Deep global evolutionary radiation in birds: diversification and trait evolution in the cosmopolitan bird family Rallidae.

    Science.gov (United States)

    Garcia-R, Juan C; Gibb, Gillian C; Trewick, Steve A

    2014-12-01

    Sufficient breadth of taxon sampling in major organisms groups is important to identify more realistic biological diversification processes that reveal the degree of historical biogeographic signal and net diversification retained in the current lineage distribution. We examine the mechanisms driving diversity in one of the major avian clades with an exceptional large-scale radiation, the family Rallidae, using the most complete species-level (∼70%) time calibrated hypothesis of evolutionary relationships produced to date. We find that Rallidae exhibit a pattern of diversification involving episodes of range expansion and regional speciation that results in most clades represented in all habitable continents. Our results suggest that several features may have played an important role on the diversification rates in Rallidae. Lineage accumulation is nearly constant and morphology (frontal shield and body size), innovate (flightlessness), habitat (forest) and distribution (insular) traits are possibly associated with increasing diversification rates along with spatial and ecological processes during the Miocene and Pliocene. Diversification and the global retention of lineage diversity have occurred in multiple lineages in Rallidae due to their dispersal ability and exploitation of ecological opportunities.

  5. Daily global solar radiation modelling using multi-layer perceptron neural networks in semi-arid region

    Directory of Open Access Journals (Sweden)

    Mawloud GUERMOUI

    2016-07-01

    Full Text Available Accurate estimation of Daily Global Solar Radiation (DGSR has been a major goal for solar energy application. However, solar radiation measurements are not a simple task for several reasons. In the cases where data are not available, it is very common the use of computational models to estimate the missing data, which are based mainly of the search for relationships between weather variables, such as temperature, humidity, sunshine duration, etc. In this respect, the present study focuses on the development of artificial neural network (ANN model for estimation of daily global solar radiation on horizontal surface in Ghardaia city (South Algeria. In this analysis back-propagation algorithm is applied. Daily mean air temperature, relative humidity and sunshine duration was used as climatic inputs parameters, while the daily global solar radiation (DGSR was the only output of the ANN. We have evaluated Multi-Layer Perceptron (MLP models to estimate DGSR using three year of measurement (2005-2008. It was found that MLP-model based on sunshine duration and mean air temperature give accurate results in term of Mean Absolute Bias Error, Root Mean Square Error, Relative Square Error and Correlation Coefficient. The obtained values of these indicators are 0.67 MJ/m², 1.28 MJ/m², 6.12%and 98.18%, respectively which shows that MLP is highly qualified for DGSR estimation in semi-arid climates.

  6. Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    S. T. Martin

    2004-01-01

    Full Text Available The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US and once for lower side (LS of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m2 (g SO4-2-1, which compare to US values of 0.030 and 13.9 m2 (g SO4-2-1. Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (FL and FU, respectively, in W m-2 are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of FL=-0.750, FU=-0.930, and DFU,L=24% for full sky calculations without clouds and FL=-0.485, FU=-0.605, and DFU,L=25% when clouds are included. Regionally, DFU,L=48% over the USA, 55% over Europe

  7. Hawking Radiation from Horizons of Reissner-Nordstr6m de Sitter Black Hole with a Global Monopole via Anomalies

    Institute of Scientific and Technical Information of China (English)

    CHEN Shi-Wu; LIU Xiong-Wei; LIN Kai; ZENG Xiao-Xiong; YANG Shu-Zheng

    2008-01-01

    Hawking radiation from cosmological horizon and event horizon of the Reissner-Nordstrom de Sitter black hole with a global monopole is studied via a new method that was propounded by Robinson and Wilzek and elaborated by Banerjee and Kulkarni. The results show that the gauge current and energy-momentum tensor fluxes, which required keeping gauge covariance and general coordinate invaxiance at the quantum level in the effective field theory, axe exactly equivalent to those of Hawking radiation from the event horizon and the cosmological horizon, respectively.

  8. Correlations during the day of diffuse solar radiation to the global solar radiation in Vigo (Spain); Correlaciones minutarias, horarias y diarias de la radiacion solar difusa a la radiacion solar global en Vigo

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, M.; Santos, J.

    2004-07-01

    In the Solar Energy Lab of the University of Vigo a weather station has been in operation since October 2001. Two Kipp and Zonen pyranometers, one of them with a shade ring, have been measuring global and diffuse solar radiation. From these data of the years 2002 and 2003, the diffuse-to-global minute, hourly and daily correlations are obtained and shown in graphs. These correlations are also plotted together with other correlations referred in the literature for comparison. The graphs show the effect of the clear-cloudy behaviour of the solar radiation for short periods of time, effect that is not seen for larger periods of time as daily periods. (Author)

  9. Globalization

    Institute of Scientific and Technical Information of China (English)

    范玮丽

    2008-01-01

    This paper mainly talks about the currently hot topic-globalization. Firstly, it brings out the general trend about globalization and how to better understand its implication. Secondly, it largely focuses on how to deal with it properly, especially for international marketers. Then, facing with the overwhelming trend, it is time for us to think about seriously what has globalization brought to us. Last but not least, it summarized the author's personal view about the future of globalization and how should we go.

  10. Retrieving air humidity, global solar radiation, and reference evapotranspiration from daily temperatures: development and validation of new methods for Mexico. Part II: radiation

    Science.gov (United States)

    Lobit, P.; López Pérez, L.; Lhomme, J. P.

    2017-07-01

    We propose a new model to estimate daily global radiation from daily temperature range measurements. This model combines that of Majumdar et al. (Sol Energy 13(4):383-394, 1972) to estimate clear sky radiation with a Gompertz function to estimate the relation between temperature range and cloud transmittance. Model parameters are estimated from historical weather data: maximum and minimum temperatures and, if available, relative humidity; no other calibration is required. The model was parametrized and validated using 788 weather stations in Mexico. When calibrated using historical humidity data, daily global radiation was estimated with a mean root mean square error of 3.06 MJ m-2 day-1. The model performed well in all situations, except for a few stations around the Gulf of Mexico and in mountain areas. When using estimated humidity, the root mean square error of prediction was only slightly degraded (3.07 MJ m-2 day-1). Possible theoretical basis and applicability of this model to other environments are discussed.

  11. Globalization

    Directory of Open Access Journals (Sweden)

    Tulio Rosembuj

    2006-12-01

    Full Text Available There is no singular globalization, nor is the result of an individual agent. We could start by saying that global action has different angles and subjects who perform it are different, as well as its objectives. The global is an invisible invasion of materials and immediate effects.

  12. Medical exposure assessment: the global approach of the United Nations Scientific Committee on the Effects of Atomic Radiation.

    Science.gov (United States)

    Shannoun, F

    2015-07-01

    The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was established in 1955 to systematically collect, evaluate, publish and share data on the global levels and effects of ionizing radiation from natural and artificial sources. Regular surveys have been conducted to determinate the frequencies of medical radiological procedure, the number of equipment and staffing and the level of global exposure using the health care level (HCL) extrapolation model. UNSCEAR surveys revealed a range of issues relating to participation, survey process, data quality and analysis. Thus, UNSCEAR developed an improvement strategy to address the existing deficiencies in data quality and collection. The major element of this strategy is the introduction of an on-line platform to facilitate the data collection and archiving process. It is anticipated that the number of countries participating in UNSCEAR's surveys will increase in the future, particularly from HCL II-IV countries.

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

    Science.gov (United States)

    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.

  14. The effects of solar activity on the global solar radiation measured at Khargha Oasis in the Western Dessert of Egypt

    Science.gov (United States)

    Shaltout, M.; Mohamed, A.

    Khargha is an Oasis in the Western Desert of Egypt of coordinates lat. 25 o 27/ N, long. 30 o 32 / E, and elevation 77.8 meter over the sea level. It is one of the driest areas in the world, the global solar radiation measured starting from January 1976 till now by station belong to the Egyptian Meteorological Authority. We used the data for the last 25 years of the 20"' Century on the daily bases, it is more than two solar cycles. The annual mean of relative humidity for Khargha is 30, and the total rainfall in mms as annual mean is less than one. Where, the evaporation in mms per day as annual mean is about 16. The total sky cover in oktas as annual mean is 0.4 at the midnight, while it is one oktas at the noon as 2annual mean, and 0.7 oktas on the mean of the day. The annual mean is 6.5 Kwh/rn /day for global solar radiation. Fourier analysis technique used to analysis the time series to show any reflection for the 11-year cycle of the solar activity on the measured global radiation in remote, clean, and dry desert area. The results indicate periodicity's similar to the solar activity periodicities, especially that of the eleven year cycle, in a good indication for the effect of solar activity on the climate change.

  15. An assessment of radiation budget data provided by the ISCCP and GEWEX-SRB

    Science.gov (United States)

    Raschke, Ehrhard; Bakan, Stephan; Kinne, Stefan

    2006-04-01

    The projects ISCCP and GEWEX-SRB compute global data sets of radiation budget components at the top of the atmosphere and at the surface. Time series range from July 1983 to June 2001, and to October 1995, respectively. Comparing monthly averages over broader zones we find that the SRB underestimates the incident radiation at TOA by more than 2-5 Wm-2 over the tropics and up to 40 Wm-2 over polar regions. The ISCCP infrared radiation fluxes near the surface and at TOA, in particular over both polar zones, are higher than those of the SRB. Clouds in the ISCCP appear optically less effective than in the SRB. Interannual and month-to-month variations are observed indicating serious errors in ancillary data. Complete reprocessing is recommended. End products need validation within this large domain in space and time with correlated radiation budget measurements at TOA and at ground.

  16. Insolation data manual and direct normal solar radiation data manual

    Energy Technology Data Exchange (ETDEWEB)

    None

    1990-07-01

    The Insolation Data Manual presents monthly averaged data which describes the availability of solar radiation at 248 National Weather Service (NWS) stations, principally in the United States. Monthly and annual average daily insolation and temperature values have been computed from a base of 24--25 years of data, generally from 1952--1975, and listed for each location. Insolation values represent monthly average daily totals of global radiation on a horizontal surface and are depicted using the three units of measurement: kJ/m{sup 2} per day, Btu/ft{sup 2} per day and langleys per day. Average daily maximum, minimum and monthly temperatures are provided for most locations in both Celsius and Fahrenheit. Heating and cooling degree-days were computed relative to a base of 18.3 C (65 F). For each station, global {bar K}{sub T} (cloudiness index) values were calculated on a monthly and annual basis. Global {bar K}{sub T} is an index of cloudiness and indicates fractional transmittance of horizontal radiation, from the top of the atmosphere to the earth's surface. The second section of this volume presents long-term monthly and annual averages of direct normal solar radiation for 235 NWS stations, including a discussion of the basic derivation process. This effort is in response to a generally recognized need for reliable direct normal data and the recent availability of 23 years of hourly averages for 235 stations. The relative inaccessibility of these data on microfiche further justifies reproducing at least the long-term averages in a useful format. In addition to a definition of terms and an overview of the ADIPA model, a discussion of model validation results is presented.

  17. Relationships Between Ice Cloud Properties and Radiative Effects from A-Train Observations and Global Climate Models

    Science.gov (United States)

    Berry, B. J.; Mace, G. G.

    2014-12-01

    Using data from the A-Train satellites, we investigate the distribution of clouds and their microphysical and radiative properties in Southeast Asia during the summer monsoon. We find an approximate balance in the top of the atmosphere (TOA) cloud radiative effect, which is largely due to commonly occurring cirrus layers that warm the atmosphere, and less frequent deep layer clouds, which produce a strong cooling at the surface. The distribution of cloud ice water path (IWP) in cirrus layers, obtained from the 2C-ICE CloudSat data product, is highly skewed with a mean value of 170 g m-2 and a median of 16 g m-2. We evaluate the fraction of the total IWP observed by CloudSat and CALIPSO individually and find that both instruments are necessary for describing the overall IWP statistics and particularly the values that are most important to cirrus radiative impact. In examining how cirrus cloud radiative effects at the TOA vary as a function of IWP, we find that cirrus with IWP less than 200 g m-2 produce a net warming. Weighting the distribution of radiative effect by the frequency of occurrence of IWP values, we find that cirrus with IWP around 20 g m-2 contribute most to heating at the TOA. We conclude that the mean IWP is a poor diagnostic of radiative impact. We suggest that climate model intercomparisons with data should focus on the median IWP because that statistic is more descriptive of the cirrus that contribute most to the radiative impacts of tropical ice clouds. Given these findings, we use the A-Train observations to address the issues of IWP occurrence and high cloud forcing in a global climate model (GCM). Our goal is to determine whether the clouds that heat the upper troposphere in the model are the same genre of clouds that heat the upper troposphere in the real atmosphere. First, we define a cloud radiative kernel that's a function of IWP to determine whether the modeled ice clouds produce similar shortwave and longwave radiative effects at the TOA

  18. A Coupled Ocean General Circulation, Biogeochemical, and Radiative Model of the Global Oceans: Seasonal Distributions of Ocean Chlorophyll and Nutrients

    Science.gov (United States)

    Gregg, Watson W.; Busalacchi, Antonio (Technical Monitor)

    2000-01-01

    A coupled ocean general circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability. and the interactions among three functional phytoplankton groups (diatoms. chlorophytes, and picoplankton) and three nutrients (nitrate, ammonium, and silicate). Basin scale (greater than 1000 km) model chlorophyll results are in overall agreement with CZCS pigments in many global regions. Seasonal variability observed in the CZCS is also represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are generally in conformance although occasional departures are apparent. Model nitrate distributions agree with in situ data, including seasonal dynamics, except for the equatorial Atlantic. The overall agreement of the model with satellite and in situ data sources indicates that the model dynamics offer a reasonably realistic simulation of phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent many aspects of the great diversity of physical, biological, chemical, and radiative environments encountered in the global oceans.

  19. Modeling the relationship between photosynthetically active radiation and global horizontal irradiance using singular spectrum analysis

    Science.gov (United States)

    Zempila, Melina-Maria; Taylor, Michael; Bais, Alkiviadis; Kazadzis, Stelios

    2016-10-01

    We report on the construction of generic models to calculate photosynthetically active radiation (PAR) from global horizontal irradiance (GHI), and vice versa. Our study took place at stations of the Greek UV network (UVNET) and the Hellenic solar energy network (HNSE) with measurements from NILU-UV multi-filter radiometers and CM pyranometers, chosen due to their long (≈1 M record/site) high temporal resolution (≈1 min) record that captures a broad range of atmospheric environments and cloudiness conditions. The uncertainty of the PAR measurements is quantified to be ±6.5% while the uncertainty involved in GHI measurements is up to ≈±7% according to the manufacturer. We show how multi-linear regression and nonlinear neural network (NN) models, trained at a calibration site (Thessaloniki) can be made generic provided that the input-output time series are processed with multi-channel singular spectrum analysis (M-SSA). Without M-SSA, both linear and nonlinear models perform well only locally. M-SSA with 50 time-lags is found to be sufficient for identification of trend, periodic and noise components in aerosol, cloud parameters and irradiance, and to construct regularized noise models of PAR from GHI irradiances. Reconstructed PAR and GHI time series capture ≈95% of the variance of the cross-validated target measurements and have median absolute percentage errors <2%. The intra-site median absolute error of M-SSA processed models were ≈8.2±1.7 W/m2 for PAR and ≈9.2±4.2 W/m2 for GHI. When applying the models trained at Thessaloniki to other stations, the average absolute mean bias between the model estimates and measured values was found to be ≈1.2 W/m2 for PAR and ≈0.8 W/m2 for GHI. For the models, percentage errors are well within the uncertainty of the measurements at all sites. Generic NN models were found to perform marginally better than their linear counterparts.

  20. MODIS/COMBINED MCD15A3H Leaf Area Index - Fraction of Photosynthetically Active Radiation 4-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  1. MODIS/AQUA MYD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  2. MODIS/COMBINED MCD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  3. MODIS/AQUA MYD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter...

  4. MODIS/COMBINED MCD15A3H Leaf Area Index - Fraction of Photosynthetically Active Radiation 4-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter...

  5. MODIS/COMBINED MCD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter...

  6. MODIS/TERRA MOD15A2 Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 1km

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  7. MODIS/COMBINED MCD15A2 Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 1km

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  8. MODIS/TERRA MOD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  9. MODIS/AQUA MYD15A2 Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 1km

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  10. Global real-time dose measurements using the Automated Radiation Measurements for Aerospace Safety (ARMAS) system

    Science.gov (United States)

    Tobiska, W. Kent; Bouwer, D.; Smart, D.; Shea, M.; Bailey, J.; Didkovsky, L.; Judge, K.; Garrett, H.; Atwell, W.; Gersey, B.; Wilkins, R.; Rice, D.; Schunk, R.; Bell, D.; Mertens, C.; Xu, X.; Wiltberger, M.; Wiley, S.; Teets, E.; Jones, B.; Hong, S.; Yoon, K.

    2016-11-01

    The Automated Radiation Measurements for Aerospace Safety (ARMAS) program has successfully deployed a fleet of six instruments measuring the ambient radiation environment at commercial aircraft altitudes. ARMAS transmits real-time data to the ground and provides quality, tissue-relevant ambient dose equivalent rates with 5 min latency for dose rates on 213 flights up to 17.3 km (56,700 ft). We show five cases from different aircraft; the source particles are dominated by galactic cosmic rays but include particle fluxes for minor radiation periods and geomagnetically disturbed conditions. The measurements from 2013 to 2016 do not cover a period of time to quantify galactic cosmic rays' dependence on solar cycle variation and their effect on aviation radiation. However, we report on small radiation "clouds" in specific magnetic latitude regions and note that active geomagnetic, variable space weather conditions may sufficiently modify the magnetospheric magnetic field that can enhance the radiation environment, particularly at high altitudes and middle to high latitudes. When there is no significant space weather, high-latitude flights produce a dose rate analogous to a chest X-ray every 12.5 h, every 25 h for midlatitudes, and every 100 h for equatorial latitudes at typical commercial flight altitudes of 37,000 ft ( 11 km). The dose rate doubles every 2 km altitude increase, suggesting a radiation event management strategy for pilots or air traffic control; i.e., where event-driven radiation regions can be identified, they can be treated like volcanic ash clouds to achieve radiation safety goals with slightly lower flight altitudes or more equatorial flight paths.

  11. Photosynthetically Available Radiation, Aqua MODIS, NPP, 0.05 degrees, Global, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS measures photosynthetically available radiation that may be used to mode primary productivity. THIS IS AN EXPERIMENTAL PRODUCT: intended strictly for...

  12. Photosynthetically Available Radiation, Aqua MODIS, NPP, 0.05 degrees, Global, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS measures photosynthetically available radiation that may be used to mode primary productivity. THIS IS AN EXPERIMENTAL PRODUCT: intended strictly for...

  13. Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    S. T. Martin

    2003-10-01

    Full Text Available The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US and once for lower side (LS of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m2  (g SO42−−1, which compare to US values of 0.030 and 13.9 m2 (g SO42−−1. Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (FL and FU, respectively, in W m2− are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of FL = −0.750, FU = −0.930, and

  14. Estimation of available global solar radiation using sunshine duration over South Korea

    Science.gov (United States)

    Das, Amrita; Park, Jin-ki; Park, Jong-hwa

    2015-11-01

    Besides designing a solar energy system, accurate insolation data is also a key component for many biological and atmospheric studies. But solar radiation stations are not widely available due to financial and technical limitations; this insufficient number affects the spatial resolution whenever an attempt is made to construct a solar radiation map. There are several models in literature for estimating incoming solar radiation using sunshine fraction. Seventeen of such models among which 6 are linear and 11 non-linear, have been chosen for studying and estimating solar radiation on a horizontal surface over South Korea. The better performance of a non-linear model signifies the fact that the relationship between sunshine duration and clearness index does not follow a straight line. With such a model solar radiation over 79 stations measuring sunshine duration is computed and used as input for spatial interpolation. Finally monthly solar radiation maps are constructed using the Ordinary Kriging method. The cross validation results show good agreement between observed and predicted data.

  15. User's guide: Nimbus-7 Earth radiation budget narrow-field-of-view products. Scene radiance tape products, sorting into angular bins products, and maximum likelihood cloud estimation products

    Science.gov (United States)

    Kyle, H. Lee; Hucek, Richard R.; Groveman, Brian; Frey, Richard

    1990-01-01

    The archived Earth radiation budget (ERB) products produced from the Nimbus-7 ERB narrow field-of-view scanner are described. The principal products are broadband outgoing longwave radiation (4.5 to 50 microns), reflected solar radiation (0.2 to 4.8 microns), and the net radiation. Daily and monthly averages are presented on a fixed global equal area (500 sq km), grid for the period May 1979 to May 1980. Two independent algorithms are used to estimate the outgoing fluxes from the observed radiances. The algorithms are described and the results compared. The products are divided into three subsets: the Scene Radiance Tapes (SRT) contain the calibrated radiances; the Sorting into Angular Bins (SAB) tape contains the SAB produced shortwave, longwave, and net radiation products; and the Maximum Likelihood Cloud Estimation (MLCE) tapes contain the MLCE products. The tape formats are described in detail.

  16. Global Climate Modeling of the Martian water cycle with improved microphysics and radiatively active water ice clouds

    CERN Document Server

    Navarro, Thomas; Forget, François; Spiga, Aymeric; Millour, Ehouarn; Montmessin, Franck

    2013-01-01

    Radiative effects of water ice clouds have noteworthy consequences on the Martian atmosphere, its thermal structure and circulation. Accordingly, the inclusion of such effects in the LMD Mars Global Climate Model (GCM) greatly modifies the simulated Martian water cycle. The intent of this paper is to address the impact of radiatively active clouds on atmospheric water vapor and ice in the GCM and improve its representation. We propose a new enhanced modeling of the water cycle, consisting of detailed cloud microphysics with dynamic condensation nuclei and a better implementation of perennial surface water ice. This physical modeling is based on tunable parameters. This new version of the GCM is compared to the Thermal Emission Spectrometer observations of the water cycle. Satisfying results are reached for both vapor and cloud opacities. However, simulations yield a lack of water vapor in the tropics after Ls=180{\\deg} which is persistent in simulations compared to observations, as a consequence of aphelion c...

  17. FW-CADIS Method for Global and Semi-Global Variance Reduction of Monte Carlo Radiation Transport Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, John C [ORNL; Peplow, Douglas E. [ORNL; Mosher, Scott W [ORNL

    2014-01-01

    This paper presents a new hybrid (Monte Carlo/deterministic) method for increasing the efficiency of Monte Carlo calculations of distributions, such as flux or dose rate distributions (e.g., mesh tallies), as well as responses at multiple localized detectors and spectra. This method, referred to as Forward-Weighted CADIS (FW-CADIS), is an extension of the Consistent Adjoint Driven Importance Sampling (CADIS) method, which has been used for more than a decade to very effectively improve the efficiency of Monte Carlo calculations of localized quantities, e.g., flux, dose, or reaction rate at a specific location. The basis of this method is the development of an importance function that represents the importance of particles to the objective of uniform Monte Carlo particle density in the desired tally regions. Implementation of this method utilizes the results from a forward deterministic calculation to develop a forward-weighted source for a deterministic adjoint calculation. The resulting adjoint function is then used to generate consistent space- and energy-dependent source biasing parameters and weight windows that are used in a forward Monte Carlo calculation to obtain more uniform statistical uncertainties in the desired tally regions. The FW-CADIS method has been implemented and demonstrated within the MAVRIC sequence of SCALE and the ADVANTG/MCNP framework. Application of the method to representative, real-world problems, including calculation of dose rate and energy dependent flux throughout the problem space, dose rates in specific areas, and energy spectra at multiple detectors, is presented and discussed. Results of the FW-CADIS method and other recently developed global variance reduction approaches are also compared, and the FW-CADIS method outperformed the other methods in all cases considered.

  18. Empirical Model for Estimating Global Solar Radiation on Horizontal Surfaces for Selected Cities in the Six Geopolitical Zones in Nigeria

    Directory of Open Access Journals (Sweden)

    Okundamiya, Michael Stephen

    2010-12-01

    Full Text Available This study proposes a temperature-based model of monthly mean daily global solar radiation on horizontal surfaces for selected cities, representing the six geopolitical zones in N igeria. The modelling was based on linear regression theory and was computed using monthly mean daily data set for minimum and maximum ambient temperatures. The results of three statistical indicators: Mean Bias Error (MBE, Root Mean Square Error (RMSE and t-statistic (TS; performed on the model along with practical comparison of the estimated and observed data validate the excellent performance accuracy of the proposed model.

  19. Empirical Model for Estimating Global Solar Radiation on Horizontal Surfaces for Selected Cities in the Six Geopolitical Zones in Nigeria

    Directory of Open Access Journals (Sweden)

    M. S. Okundamiya

    2011-01-01

    Full Text Available This study proposes a temperature-based model of monthly mean daily global solar radiation on horizontal surfaces for selected cities, representing the six geopolitical zones in Nigeria. The modelling was based on linear regression theory and was computed using monthly mean daily data set for minimum and maximum ambient temperatures. The results of three statistical indicators: Mean Bias Error (MBE, Root Mean Square Error (RMSE, and t-statistic (TS, performed on the model along with practical comparison of the estimated and observed data, validate the excellent performance accuracy of the proposed model.

  20. Remarks on global existence and exponential stability of solutions for the viscous radiative and reactive gas with large initial data

    Science.gov (United States)

    Zhang, Jianlin

    2017-04-01

    In this paper, we study a large time behavior of the global spherically or cylindrically symmetric solutions in H 1 for the compressible viscous radiative and reactive gas in multi-dimension with large initial data. Precisely, if the initial data are spherically symmetric or cylindrically symmetric, the smallness of initial data is not needed. The main concern of the present paper is to investigate the exponential stability of a solution toward the stationary solution as time goes to infinity. We obtain the uniform positive lower and upper bounds of the density by using different methods.

  1. Site specific X-ray induced changes in organic and metal organic compounds and their influence on global radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, Desiree Ellen

    2012-07-15

    The aim of this work was to systematically investigate the effects of specific and global X-ray radiation damage to biological samples and obtain a conclusive model to describe the underlying principles. Based on the systematic studies performed in this work, it was possible to propose two conclusive mechanisms to describe X-ray induced photoreduction and global radiation damage. The influence of chemical composition, temperature and solvent on X-ray induced photoreduction was investigated by X-ray Absorption Near Edge Spectroscopy and single crystal X-ray diffraction of two B12 cofactors - cyano- and methylcobalamin - as well as iron(II) and iron(III) complexes. The obtained results revealed that X-ray induced photoreduction is a ligand dependent process, with a redox reaction taking place within the complex. It could further be shown that selective hydrogen abstraction plays an important role in the process of X-ray induced photoreduction. Based on the experimental results of this work, a model to describe X-ray induced photoreduction of metal organic complexes could be proposed. The process of X-ray induced hydrogen abstraction was further investigated in a combined X-ray and neutron diffraction study on the amino acids L-serine and L-alanine, which were used as model compounds for proteins, and the nucleoside deoxythymidine (thymidine) as a model for DNA. A damage mechanism for L-serine could be found. It involves the abstraction of two hydrogen atoms, one from the hydroxyl group and one from the adjacent methylene group. Such a hydrogen abstraction results in the formation of a carbonyl group. X-ray diffraction measurements on cyano- and methylcobalamin as well as on three metal amino acid complexes, containing nickel(II) and copper(II), respectively, were conducted to investigate the contribution of X-ray induced photoreduction to global radiation damage. Results from these measurements combined with the results from L-serine, L-alanine and thymidine allowed

  2. The link between extreme precipitation and convective organization in a warming climate: Global radiative-convective equilibrium simulations

    Science.gov (United States)

    Pendergrass, Angeline G.; Reed, Kevin A.; Medeiros, Brian

    2016-11-01

    The rate of increase of extreme precipitation in response to global warming varies dramatically across climate model simulations, particularly over the tropics, for reasons that have yet to be established. Here we propose one potential mechanism: changing organization of convection with climate. We analyze a set of simulations with the Community Atmosphere Model version 5 with an idealized global radiative-convective equilibrium configuration forced by fixed sea surface temperatures varying in 2° increments from 285 to 307 K. In these simulations, convective organization varies from semiorganized in cold simulations, disorganized in warm simulations, and abruptly becomes highly organized at just over 300 K. The change in extreme precipitation with warming also varies across these simulations, including a large increase at the transition from disorganized to organized convection. We develop an extreme precipitation-focused metric for convective organization and use this to explore their connection.

  3. The use of solar simulation systems for producing artificial global radiation for the purpose of determining the heat load of rooms

    Science.gov (United States)

    Kalt, A. C.

    1975-01-01

    Certain climatic tests which require solar and sky radiation were carried out in the laboratory by using simulated global radiation. The advantages of such a method of measurement and the possibilities and limitations resulting from the simulation of global radiation are described. Experiments concerning the thermal load in rooms were conducted in order to test the procedure. In particular, the heat gain through a window with sunshade is discussed, a venetian blind between the panes of a double-glazed window being used in most cases.

  4. Role of aerosols in radiative forcing of climate change: Global mean and uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, S.E.

    1998-10-01

    Anthropogenically induced climate change is of great current interest because of increases in atmospheric loading of infrared active (greenhouse) gases over the past 150 years and the inferred resultant increase in infrared radiation flux in the troposphere. However, the climate change ascribed to such increases, not to mention predictions of future climate change in response to prospective changes in the earth`s radiation budget, is based virtually entirely on climate model simulations of how the earth`s climate would respond to changes in radiation rather than on empirically established relationships between changes in the earth`s radiation budget and climate change. There is thus an urgent need to evaluate the performance of climate models to ascertain the accuracy with which they represent the changes in temperature and other indicia of climate that have been observed over the industrial period. Such an evaluation, however, requires an accurate assessment of the totality of changes in the earth`s radiation budget in both the longwave (thermal infrared) and shortwave (solar) spectral regions, not just of changes in the longwave due to increased concentrations of long-lived greenhouse gases.

  5. Thermal instability (or not?) in three-dimensional, global, radiative GRMHD simulations of geometrically thin discs

    CERN Document Server

    Mishra, B; Johnson, L C; Kluźniak, W

    2016-01-01

    We present results of a set of three-dimensional, general relativistic radiation magnetohydro- dynamics simulations of thin accretion discs to test their thermal stability. We consider two cases, one that is initially radiation-pressure dominated and expected to be thermally unstable and another that is initially gas-pressure dominated and expected to remain stable. Indeed, we find that cooling dominates over heating in the radiation-pressure-dominated case, causing the disc to collapse vertically on the local cooling timescale. On the other hand, the gas-pressure- dominated case, which was run for twice as long as the radiation-pressure-dominated case, remains stable, with heating and cooling roughly in balance. Because the radiation-pressure- dominated disc collapses to the point that we are no longer able to resolve it, we had to terminate the simulation. Thus, we do not know for sure whether it might find a much thinner, stable solution or if it will make a transition to unstable expansion and exhibit lim...

  6. Three-dimensional, global, radiative GRMHD simulations of a thermally unstable disc

    Science.gov (United States)

    Mishra, B.; Fragile, P. C.; Johnson, L. C.; Kluźniak, W.

    2016-12-01

    We present results of a set of three-dimensional, general relativistic radiation magnetohydrodynamics simulations of thin accretion discs around a non-rotating black hole to test their thermal stability. We consider two cases, one that is initially radiation-pressure-dominated and expected to be thermally unstable and another that is initially gas-pressure dominated and expected to remain stable. Indeed, we find that cooling dominates over heating in the radiation-pressure-dominated model, causing the disc to collapse vertically on roughly the local cooling time-scale. We also find that heating and cooling within the disc have a different dependence on the mid-plane pressure - a prerequisite of thermal instability. Comparison of our data with the relevant thin-disc thermal equilibrium curve suggests that our disc may be headed for the thermally stable, gas-pressure-dominated branch. However, because the disc collapses to the point that we are no longer able to resolve it, we had to terminate the simulation. On the other hand, the gas-pressure-dominated model, which was run for twice as long as the radiation-pressure-dominated one, remains stable, with heating and cooling roughly in balance. Finally, the radiation-pressure-dominated simulation shows some evidence of viscous instability. The strongest evidence is in plots of surface density, which show the disc breaking up into rings.

  7. Cirrus cloud radiative forcing on surface-level shortwave and longwave irradiances at regional and global scale

    Science.gov (United States)

    Dupont, J. C.; Haeffelin, M.; Long, C. N.

    2009-04-01

    Cirrus clouds not only play a major role in the energy budget of the Earth-Atmosphere system, but are also important in the hydrological cycle. According to satellite passive remote sensing high-altitude clouds cover as much as 40% of the earth's surface on average and can reach 70% of cloud cover over the Tropics. Hence, given their very large cloud cover, the relatively small instantaneous radiative effects of these cirrus clouds can engender a significant cumulative radiative forcing at the surface. Precise calculations of the cirrus cloud radiative forcing are obtained from the difference between measured radiative fluxes downwelling at the surface in the presence of cirrus clouds (broadband flux measurements) and computed clear sky references (parametric models with RMS error water vapor content obtained in studying the 4 observatories allows us to quantify the combined influence of aerosol optical thickness and integrated water vapor on CRFSW* : 10 to 20 % CRFSW* range for turbid and pristine atmosphere. Moreover, the sensitivity of the CRFLW to both cloud emissivity and cloud temperature (noted CRFLW*) is established and the influence of integrated water vapor on CRFLW* quantified: partial infrared opacity for arctic site (dry atmosphere) and quasi-total infrared opacity for tropical site (wet atmosphere), respectively 20% and 97% of opacity. Cirrus cloud radiative forcing parameterizations are hence developed starting from the ground-based collocated measurements. They relate CRFSW or CRFLW to cirrus cloud macrophysical properties, atmospheric humidity, aerosol content and solar zenith angle. Satellite measurements are used next as input parameters to the cirrus cloud radiative forcing parameterizations to calculate CRFSW and CRFLW at global scale. CALIOP provide aerosol and cirrus cloud properties and AIRS the integrated water vapor. Meridian distribution are shown and discussed. They reveal a positive cirrus cloud net radiative effect (CRFSW + CRFLW) from

  8. Seasonal Distributions of Global Ocean Chlorophyll and Nutrients: Analysis with a Coupled Ocean General Circulation Biogeochemical, and Radiative Model

    Science.gov (United States)

    Gregg, Watson W.

    1999-01-01

    A coupled general ocean circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. The model is driven by climatological meteorological conditions, cloud cover, and sea surface temperature. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability, and the interactions among three functional phytoplankton groups (diatoms, chorophytes, and picoplankton) and three nutrient groups (nitrate, ammonium, and silicate). Phytoplankton groups are initialized as homogeneous fields horizontally and vertically, and allowed to distribute themselves according to the prevailing conditions. Basin-scale model chlorophyll results are in very good agreement with CZCS pigments in virtually every global region. Seasonal variability observed in the CZCS is also well represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are also in good conformance, although occasional departures are apparent. Agreement of nitrate distributions with in situ data is even better, including seasonal dynamics, except for the equatorial Atlantic. The good agreement of the model with satellite and in situ data sources indicates that the model dynamics realistically simulate phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization, and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent the great diversity of physical, biological

  9. Globalization

    DEFF Research Database (Denmark)

    Plum, Maja

    Globalization is often referred to as external to education - a state of affair facing the modern curriculum with numerous challenges. In this paper it is examined as internal to curriculum; analysed as a problematization in a Foucaultian sense. That is, as a complex of attentions, worries, ways...... of reasoning, producing curricular variables. The analysis is made through an example of early childhood curriculum in Danish Pre-school, and the way the curricular variable of the pre-school child comes into being through globalization as a problematization, carried forth by the comparative practices of PISA...

  10. Estimation of Radiative Efficiency of Chemicals with Potentially Significant Global Warming Potential

    Data.gov (United States)

    U.S. Environmental Protection Agency — The set of commercially available chemical substances in commerce that may have significant global warming potential (GWP) is not well defined. Although there are...

  11. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    Directory of Open Access Journals (Sweden)

    Z. Yu

    2012-07-01

    Full Text Available High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss plants. We conducted a meta-analysis based on a global data set of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0 and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global data set, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons, without major change in cloudiness, could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  12. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    Directory of Open Access Journals (Sweden)

    Z. Yu

    2012-02-01

    Full Text Available High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss plants. We conducted a meta-analysis based on a global dataset of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0 and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global dataset, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of temperature and growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  13. An assessment of a revised Olmo et al. model to predict solar global radiation on a tilted surface at Beer Sheva, Israel

    Energy Technology Data Exchange (ETDEWEB)

    Evseev, Efim G.; Kudish, Avraham I. [Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, ED Bergmann Campus, Beer Sheva 84105 (Israel)

    2009-01-15

    A model to convert horizontal solar global radiation to that on a tilted surface is presented. It is based upon a relatively simple model proposed by [Olmo FJ, Vida J, Foyo I, Castro-Diez Y, Alados-Arboledas L. Prediction of global irradiance on inclined surfaces from horizontal global irradiance. Energy 24 (1999) 689-704]., which requires only measurements of horizontal solar radiation but was found to produce significant errors when tested with data from another site. The present model assumes the availability of databases for at least two of the three solar radiation types, viz., global, beam and diffuse. The horizontal global radiation is converted to that on a tilted surface by applying the Olmo model to the diffuse component, whereas the beam component is converted by using the geometrical relationship between the two surfaces. The original Olmo anisotropic radiation correction factor is now assumed to be a function of sky conditions. The solar radiation databases were converted to subsets corresponding to clear, partially cloudy and cloudy sky based upon clearness index values. The three anisotropic correction factors were determined by fitting to a 12-months database. The present model was then tested by applying it to a second database consisting of 24-months not involved in the model development. It was found to give better results than three highly regarded more complex models. (author)

  14. GLOBAL ELECTROMAGNETIC RADIATION POLLUTION: RISK ASSESSMENT FROM FIELD MEASUREMENTS AND ANIMAL EXPERIMENTS

    Science.gov (United States)

    Fragkopoulou, A. F.; Margaritis, L. H.

    2009-12-01

    The extended use of wireless technology throughout the globe in almost all developed and non-developed countries has forced a large number of scientists to get involved in the investigation of the effects. The major issue is that unlike other forms of radiation exposure, this “non-ionizing electromagnetic radiation” was not present throughout the evolution of life in earth and therefore there are no adaptive mechanisms evolved. All organisms are vulnerable to the possible effects of radiation depending on the actual exposure level. “Safety limits” on the power density have been proposed but ongoing research has shown that these limits are not really safe for humans, not mentioning the entire population of living creatures on earth. The so called “Electrosmog Pollution” originating from the numerous radio and TV stations, communication satellite emission, but most importantly from mobile phone mast antennas, are of major concern, because it is gradually increasing at exponential rate. Therefore the key question is, do living organisms react upon their exposure to fields of non ionizing electromagnetic radiation? To have this question answered extensive research is being performed in various laboratories. One approach of our research includes field measurements within houses and classrooms, since a considerable proportion of the population in each country is exposed to the radiation coming from the nearby mast stations, in order to make a risk assessment. The measurements showed that in many cases the actual radiation present was potentially harmful. In other words, although the measured values were below the national safety levels, nevertheless they were above the levels of other countries. Therefore it has been suggested that a new cellular network should be constructed in order to minimize radiation levels in living areas and schools. Our experimental work is focusing on the elucidation of the effects of non-ionizing EMFs on mice exposed to mobile

  15. Monthly variations in the atmospheric transmission for cloudless skies as inferred from the correlation of daily global radiation with hours of sunshine for Spain

    Energy Technology Data Exchange (ETDEWEB)

    Soler, A.

    1986-01-01

    The well known correlation between global radiation and sunshine duration is discussed. The monthly variations of the atmospheric transmission, for cloudless skies for some locations in Spain are discussed. The Spanish solar radiation measurement network is equipped with two types of pyranometers: Kipp and Zonen model CM-5 pyranometers from which hourly values of the global radiation are obtained after evaluating the recorded output, and bimetallic pyranometers of daily rotation. Only the high quality data obtained with Kipp and Zonen pyranometers should be used in scientific study of this nature. However, correlations were also performed for data obtained in locations equipped with SIAP pyranometers because they have been extensively used in research projects where solar radiation data are required, and for making maps of solar radiation.

  16. Establishing a Global Radiation Oncology Collaboration in Education (GRaCE): Objectives and priorities

    NARCIS (Netherlands)

    Turner, S.; Eriksen, J.G.; Trotter, T.; Verfaillie, C.; Benstead, K.; Giuliani, M.; Poortmans, P.; Holt, T.; Brennan, S.; Potter, R.

    2015-01-01

    Representatives from countries and regions world-wide who have implemented modern competency-based radiation- or clinical oncology curricula for training medical specialists, met to determine the feasibility and value of an ongoing international collaboration. In this forum, educational leaders from

  17. The influence of eruption season on the global aerosol evolution and radiative impact of tropical volcanic eruptions

    Directory of Open Access Journals (Sweden)

    M. Toohey

    2011-12-01

    Full Text Available Simulations of tropical volcanic eruptions using a general circulation model with coupled aerosol microphysics are used to assess the influence of season of eruption on the aerosol evolution and radiative impacts at the Earth's surface. This analysis is presented for eruptions with SO2 injection magnitudes of 17 and 700 Tg, the former consistent with estimates of the 1991 Mt. Pinatubo eruption, the later a near-"super eruption". For each eruption magnitude, simulations are performed with eruptions at 15° N, at four equally spaced times of year. Sensitivity to eruption season of aerosol optical depth (AOD, clear-sky and all-sky shortwave (SW radiative flux is quantified by first integrating each field for four years after the eruption, then calculating for each cumulative field the absolute or percent difference between the maximum and minimum response from the four eruption seasons. Eruption season has a significant influence on AOD and clear-sky SW radiative flux anomalies for both eruption magnitudes. The sensitivity to eruption season for both fields is generally weak in the tropics, but increases in the mid- and high latitudes, reaching maximum values of ~75 %. Global mean AOD and clear-sky SW anomalies show sensitivity to eruption season on the order of 15–20 %, which results from differences in aerosol effective radius for the different eruption seasons. Smallest aerosol size and largest cumulative impact result from a January eruption for Pinatubo-magnitude eruption, and from a July eruption for the near-super eruption. In contrast to AOD and clear-sky SW anomalies, all-sky SW anomalies are found to be insensitive to season of eruption for the Pinatubo-magnitude eruption experiment, due to the reflection of solar radiation by clouds in the mid- to high latitudes. However, differences in all-sky SW anomalies between eruptions in different seasons are significant for the larger eruption magnitude, and the ~15 % sensitivity to

  18. Impacts of global open-fire aerosols on direct radiative, cloud and surface-albedo effects simulated with CAM5

    Science.gov (United States)

    Jiang, Yiquan; Lu, Zheng; Liu, Xiaohong; Qian, Yun; Zhang, Kai; Wang, Yuhang; Yang, Xiu-Qun

    2016-11-01

    Aerosols from open-land fires could significantly perturb the global radiation balance and induce climate change. In this study, Community Atmosphere Model version 5 (CAM5) with prescribed daily fire aerosol emissions is used to investigate the spatial and seasonal characteristics of radiative effects (REs, relative to the case of no fires) of open-fire aerosols including black carbon (BC) and particulate organic matter (POM) from 2003 to 2011. The global annual mean RE from aerosol-radiation interactions (REari) of all fire aerosols is 0.16 ± 0.01 W m-2 (1σ uncertainty), mainly due to the absorption of fire BC (0.25 ± 0.01 W m-2), while fire POM induces a small effect (-0.05 and 0.04 ± 0.01 W m-2 based on two different methods). Strong positive REari is found in the Arctic and in the oceanic regions west of southern Africa and South America as a result of amplified absorption of fire BC above low-level clouds, in general agreement with satellite observations. The global annual mean RE due to aerosol-cloud interactions (REaci) of all fire aerosols is -0.70 ± 0.05 W m-2, resulting mainly from the fire POM effect (-0.59 ± 0.03 W m-2). REari (0.43 ± 0.03 W m-2) and REaci (-1.38 ± 0.23 W m-2) in the Arctic are stronger than in the tropics (0.17 ± 0.02 and -0.82 ± 0.09 W m-2 for REari and REaci), although the fire aerosol burden is higher in the tropics. The large cloud liquid water path over land areas and low solar zenith angle of the Arctic favor the strong fire aerosol REaci (up to -15 W m-2) during the Arctic summer. Significant surface cooling, precipitation reduction and increasing amounts of low-level cloud are also found in the Arctic summer as a result of the fire aerosol REaci based on the atmosphere-only simulations. The global annual mean RE due to surface-albedo changes (REsac) over land areas (0.03 ± 0.10 W m-2) is small and statistically insignificant and is mainly due to the fire BC-in-snow effect (0.02 W m-2) with the maximum albedo effect

  19. Global Structure of Three Distinct Accretion Flows and Outflows around Black Holes through Two-Dimensional Radiation-Magnetohydrodynamic Simulations

    CERN Document Server

    Ohsuga, Ken

    2011-01-01

    We present the detailed global structure of black hole accretion flows and outflows through newly performed two-dimensional radiation-magnetohydrodynamic simulations. By starting from a torus threaded with weak toroidal magnetic fields and by controlling the central density of the initial torus, rho_0, we can reproduce three distinct modes of accretion flow. In model A with the highest central density, an optically and geometrically thick supercritical accretion disk is created. The radiation force greatly exceeds the gravity above the disk surface, thereby driving a strong outflow (or jet). Because of the mild beaming, the apparent (isotropic) photon luminosity is ~22L_E (where L_E is the Eddington luminosity) in the face-on view. Even higher apparent luminosity is feasible if we increase the flow density. In model B with a moderate density, radiative cooling of the accretion flow is so efficient that a standard-type, cold, and geometrically thin disk is formed at radii greater than ~7R_S (where R_S is the S...

  20. Global Radiation-Magnetohydrodynamic Simulations of Black Hole Accretion Flow and Outflow: Unified Model of Three States

    CERN Document Server

    Ohsuga, Ken; Mori, Masao; Kato, Yoshiaki

    2009-01-01

    Black-hole accretion systems are known to possess several distinct modes (or spectral states), such as low/hard state, high/soft state, and so on. Since the dynamics of the corresponding flows is distinct, theoretical models were separately discussed for each state. We here propose a unified model based on our new, global, two-dimensional radiation-magnetohydrodynamic simulations. By controlling a density normalization we could for the first time reproduce three distinct modes of accretion flow and outflow with one numerical code. When the density is large (model A), a geometrically thick, very luminous disk forms, in which photon trapping takes place. When the density is moderate (model B), the accreting gas can effectively cool by emitting radiation, thus generating a thin disk, i.e., the soft-state disk. When the density is too low for radiative cooling to be important (model C), a disk becomes hot, thick, and faint; i.e., the hard-state disk. The magnetic energy is amplified within the disk up to about tw...

  1. An Updated Estimation of Radiative Forcing due to CO2 and Its Effect on Global Surface Temperature Change

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; ZHANG Ruoyu; SHI Guangyu

    2013-01-01

    New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model.The stratospheric adjusted radiative forcing (ARF)due to CO2 from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m-2,which was 17% larger than that of the IPCC's 4th Assessment Report because of the rapid increase in CO2 concentrations since 2005.A new formula is proposed to accurately describe the relationship between the ARF of CO2 and its concentration.Furthermore,according to the relationship between the ARF and surface temperature change,possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2 increases to 1.5,2,2.5,3,3.5 and 4 times that of the concentration in the year 2008.The result was values of +2.2℃,+3.8℃,+5.1℃,+6.2℃,+7.1℃ and +8.0℃ respectively,based on a middle-level climate sensitivity parameter of 0.8 K (W m-2)-1.Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios (pulsed and sustained emissions) as a comparison,according to the Absolute Global Temperature change Potential (AGTP) of CO2.Results showed that CO2 will likely continue to contribute to global warming if no emission controls are imposed,and the effect on the Earth-atmosphere system will be difficult to restore to its original level.

  2. A comparison of global reanalyses to satellite observations: quantifying errors in Cloud Fraction and TOA cloud radiative forcings

    Science.gov (United States)

    Dolinar, E. K.; Dong, X.; Xi, B.

    2014-12-01

    As the improvements of observing systems, model parameterizations, and advanced assimilation techniques, a few reanalyses data sets become available; however, it is necessary to understand their strengths and biases before exploiting them. In this study, we investigate five contemporary reanalyses (20CR, CFSR, Era-Interim, JRA-25, and MERRA). In detail, we first compared the cloud fraction, TOA radiation fluxes and cloud radiative forcings using CERES MODIS SYN1deg and EBAF products on the global scale. We then analyze the differences and similarities between these parameters in tropical and mid-latitudes under convective and subsidence regimes. It is important to note that CERES MODIS and EBAF results are used as reference to evaluate these simulated parameters, and these data cover the period from 03/2000 to 02/2012. The preliminary results show that most of the reanalyses under estimate cloud fraction on global average, and the SW, LW, and Net CRFs are biased by as much as 3.9 (CFSR), -8.7 (JRA-25), and -5.7 (JRA-25) Wm-2, respectively. Convective and subsidence regimes are identified as the strong ascending and descending branches of the large general circulation in the tropics and mid-latitudes. This metric helps to identify the physical characteristics in specific areas and the types of clouds that reside there. Clouds are typically over estimated in convective areas while in the subsidence region clouds are under estimated. Sensitivity studies show that these regimes exhibit different regressive behaviors when comparing cloud fraction to CRFs, especially in the LW CRF. The error analysis reveals information that can be useful for modelers so that they may develop better parameterizations for clouds and how they interact with incoming solar and outgoing infrared radiation.

  3. Hawking radiation of Dirac monopoles from the global monopole black hole with quantum gravity effects

    Science.gov (United States)

    Jusufi, Kimet; Apostolovska, Gordana

    2016-12-01

    In this paper we study the quantum tunneling of Dirac magnetic monopoles from the global monopole black hole under quantum gravity effects. We start from the modified Maxwell's equations and the Generalized Uncertainty Relation (GUP), to recover the GUP corrected temperature for the global monopole black hole by solving the modified Dirac equation via Hamilton-Jacobi method. Furthermore, we also include the quantum corrections beyond the semiclassical approximation, in particular, first we find the logarithmic corrections of GUP corrected entropy and finally we calculate the GUP corrected specific heat capacity. It is argued that the GUP effects may prevent a black hole from complete evaporation and leave remnants.

  4. A New Database of Global and Direct Solar Radiation Using the Eastern Meteosat Satellite, Models and Validation

    Directory of Open Access Journals (Sweden)

    Ana Gracia Amillo

    2014-08-01

    Full Text Available We present a new database of solar radiation at ground level for Eastern Europe and Africa, the Middle East and Asia, estimated using satellite images from the Meteosat East geostationary satellites. The method presented calculates global horizontal (G and direct normal irradiance (DNI at hourly intervals, using the full Meteosat archive from 1998 to present. Validation of the estimated global horizontal and direct normal irradiance values has been performed by comparison with high-quality ground station measurements. Due to the low number of ground measurements in the viewing area of the Meteosat Eastern satellites, the validation of the calculation method has been extended by a comparison of the estimated values derived from the same class of satellites but positioned at 0°E, where more ground stations are available. Results show a low overall mean bias deviation (MBD of +1.63 Wm−2 or +0.73% for global horizontal irradiance. The mean absolute bias of the individual station MBD is 2.36%, while the root mean square deviation of the individual MBD values is 3.18%. For direct normal irradiance the corresponding values are overall MBD of +0.61 Wm−2 or +0.62%, while the mean absolute bias of the individual station MBD is 5.03% and the root mean square deviation of the individual MBD values is 6.30%. The resulting database of hourly solar radiation values will be made freely available. These data will also be integrated into the PVGIS web application to allow users to estimate the energy output of photovoltaic (PV systems not only in Europe and Africa, but now also in Asia.

  5. Comparison of Direct Normal Irradiance Derived from Silicon and Thermopile Global Hemispherical Radiation Detectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Myers, D. R.

    2010-01-01

    Concentrating solar applications utilize direct normal irradiance (DNI) radiation, a measurement rarely available. The solar concentrator industry has begun to deploy numerous measurement stations to prospect for suitable system deployment sites. Rotating shadowband radiometers (RSR) using silicon photodiodes as detectors are typically deployed. This paper compares direct beam estimates from RSR to a total hemispherical measuring radiometer (SPN1) multiple fast thermopiles. These detectors simultaneously measure total and diffuse radiation from which DNI can be computed. Both the SPN1 and RSR-derived DNI are compared to DNI measured with thermopile pyrheliometers. Our comparison shows that the SPN1 radiometer DNI estimated uncertainty is somewhat greater than, and on the same order as, the RSR DNI estimates for DNI magnitudes useful to concentrator technologies.

  6. Global micro RNA expression in papillary thyroid carcinomas of young patients exposed to radiation

    Energy Technology Data Exchange (ETDEWEB)

    Unger, K.; Elmahjoub, A.; Thomas, G. [Human Cancer Studies Group, Surgery and Cancer, Imperial College London, London (United Kingdom); Bogdanova, T. [Institute of Endocrinology and Metabolism, Academy of Medical Sciences of the Ukraine, Kiew (Ukraine)

    2012-07-01

    One of the main effects of the Chernobyl reactor accident is an increase in childhood papillary thyroid carcinomas (PTC) in the regions that were contaminated with radio-iodine from the fallout. Despite a considerable research effort, molecular profiles have yet to be identified that reliably distinguish between age matched patients with radiation associated and sporadic PTCs. Expression of micro RNAs (miRNA) have recently been studied extensively in many different cancer types. MiRNAs have the potential to provide insights into the network of molecular pathways that are involved in the development of tumorigenesis as they are involved in the regulation of networks of mRNAs. In addition, miRNAs can be studied in formalin-fixed paraffin embedded material, making them ideal for clinical studies. This study was designed specifically to identify differentially expressed miRNAs in patients with childhood PTC that were exposed (n=11) and non-exposed (n=9) to irradiation. The results suggest that in radiation-associated childhood PTC DNA repair processes which are reflected by genes that encode DNA-binding proteins are de-regulated. DNA mutation and double-strand breaks are induced by ionising radiation and subsequent mis-repair and inactivation of tumour suppressor genes and the activation of oncogenes leads to growth and proliferation of the tumour cell. These findings suggest that in addition to the MAP kinase pathway which is known to be a key pathway in PTC, additional pathways such as the Fc epsilon RI signalling, the VEGF pathway and p53 signalling pathway seem to be involved in radiation-associated tumorigenesis of PTC

  7. Multiresolution analysis of the spatiotemporal variability in global radiation observed by a dense network of 99 pyranometers

    Science.gov (United States)

    Lakshmi Madhavan, Bomidi; Deneke, Hartwig; Witthuhn, Jonas; Macke, Andreas

    2017-03-01

    The time series of global radiation observed by a dense network of 99 autonomous pyranometers during the HOPE campaign around Jülich, Germany, are investigated with a multiresolution analysis based on the maximum overlap discrete wavelet transform and the Haar wavelet. For different sky conditions, typical wavelet power spectra are calculated to quantify the timescale dependence of variability in global transmittance. Distinctly higher variability is observed at all frequencies in the power spectra of global transmittance under broken-cloud conditions compared to clear, cirrus, or overcast skies. The spatial autocorrelation function including its frequency dependence is determined to quantify the degree of similarity of two time series measurements as a function of their spatial separation. Distances ranging from 100 m to 10 km are considered, and a rapid decrease of the autocorrelation function is found with increasing frequency and distance. For frequencies above 1/3 min-1 and points separated by more than 1 km, variations in transmittance become completely uncorrelated. A method is introduced to estimate the deviation between a point measurement and a spatially averaged value for a surrounding domain, which takes into account domain size and averaging period, and is used to explore the representativeness of a single pyranometer observation for its surrounding region. Two distinct mechanisms are identified, which limit the representativeness; on the one hand, spatial averaging reduces variability and thus modifies the shape of the power spectrum. On the other hand, the correlation of variations of the spatially averaged field and a point measurement decreases rapidly with increasing temporal frequency. For a grid box of 10 km × 10 km and averaging periods of 1.5-3 h, the deviation of global transmittance between a point measurement and an area-averaged value depends on the prevailing sky conditions: 2.8 (clear), 1.8 (cirrus), 1.5 (overcast), and 4.2 % (broken

  8. Global model simulations of the impact of ocean-going ships on aerosols, clouds, and the radiation budget

    Directory of Open Access Journals (Sweden)

    A. Lauer

    2007-10-01

    Full Text Available International shipping contributes significantly to the fuel consumption of all transport related activities. Specific emissions of pollutants such as sulfur dioxide (SO2 per kg of fuel emitted are higher than for road transport or aviation. Besides gaseous pollutants, ships also emit various types of particulate matter. The aerosol impacts the Earth's radiation budget directly by scattering and absorbing the solar and thermal radiation and indirectly by changing cloud properties. Here we use ECHAM5/MESSy1-MADE, a global climate model with detailed aerosol and cloud microphysics to study the climate impacts of international shipping. The simulations show that emissions from ships significantly increase the cloud droplet number concentration of low marine water clouds by up to 5% to 30% depending on the ship emission inventory and the geographic region. Whereas the cloud liquid water content remains nearly unchanged in these simulations, effective radii of cloud droplets decrease, leading to cloud optical thickness increase of up to 5–10%. The sensitivity of the results is estimated by using three different emission inventories for present-day conditions. The sensitivity analysis reveals that shipping contributes to 2.3% to 3.6% of the total sulfate burden and 0.4% to 1.4% to the total black carbon burden in the year 2000 on the global mean. In addition to changes in aerosol chemical composition, shipping increases the aerosol number concentration, e.g. up to 25% in the size range of the accumulation mode (typically >0.1 μm over the Atlantic. The total aerosol optical thickness over the Indian Ocean, the Gulf of Mexico and the Northeastern Pacific increases by up to 8–10% depending on the emission inventory. Changes in aerosol optical thickness caused by shipping induced modification of aerosol particle number concentration and chemical composition lead to a change in the shortwave radiation budget at the top of the

  9. Estimativas das componentes da radiação solar incidente em superfícies inclinadas baseadas na radiação global horizontal Estimates of solar radiation components on a tilted surface based on global horizontal radiation

    Directory of Open Access Journals (Sweden)

    Adilson P. Souza

    2011-03-01

    Full Text Available Foram avaliadas equações estatísticas de estimativas com agrupamentos de dados anuais e mensais e suas respectivas validações, para as componentes global, direta e difusa da radiação solar incidente em superfícies inclinadas a 12,85, 22,85 e 32,85º, com face para o Norte, nas condições climáticas e geográficas de Botucatu, SP. Empregou-se as frações das três componentes da radiação a do topo da atmosfera em correlação com o coeficiente de transmissividade atmosférica do plano horizontal, em uma base de dados de abril/1998 a dezembro/2007, cujas medidas nas três inclinações ocorreram em diferentes períodos, todavia concomitantes ao plano horizontal. O aumento do ângulo de inclinação da superfície propiciou aumento do espalhamento dos valores diários do índice de claridade para superfícies inclinada e horizontal. Nos agrupamentos anuais os piores desempenhos foram verificados na estimativa da radiação difusa diária para superfície inclinada, com valores máximos de espalhamentos iguais a 3,89 MJ m-2 d-1 (43,65% e ajustamento em torno de 62%. Na estimativa das componentes global e direta da radiação solar nos planos inclinados, podem ser aplicadas, tanto as equações anuais como as mensais, com desempenhos dependentes das condições climáticas.Statistics equations and validations with groups of annual and monthly data were evaluated for global, direct and diffuse solar radiation components incident on the tilted surface to 12.85, 22.85 and 32.85° with the face North, in climate and geographical conditions of Botucatu, SP. It was employed the fractions of three components of extraterrestrial radiation in correlation with the coefficient clearness index horizontal plane, in a database of April/1998 to December/2007, whose measures at different periods in three inclinations, however concomitant to the horizontal plane. Increasing the angle of the surface led to increased scattering of the daily values of

  10. MONTHLY AVERAGE FLOW IN RÂUL NEGRU HYDROGRAPHIC BASIN

    Directory of Open Access Journals (Sweden)

    VIGH MELINDA

    2014-03-01

    Full Text Available Râul Negru hydrographic basin represents a well individualised and relatively homogenous physical-geographical unity from Braşov Depression. The flow is controlled by six hydrometric stations placed on the main collector and on two of the most powerful tributaries. Our analysis period is represented by the last 25 years (1988 - 2012 and it’s acceptable for make pertinent conclusions. The maximum discharge month is April, that it’s placed in the high flow period: March – June. Minimum discharges appear in November - because of the lack of pluvial precipitations; in January because of high solid precipitations and because of water volume retention in ice. Extreme discharge frequencies vary according to their position: in the mountain area – small basin surface; into a depression – high basin surface. Variation coefficients point out very similar variation principles, showing a relative homogeneity of flow processes.

  11. The influence of eruption season on the global aerosol evolution and radiative impact of tropical volcanic eruptions

    Directory of Open Access Journals (Sweden)

    M. Toohey

    2011-08-01

    Full Text Available Simulations of tropical volcanic eruptions using a general circulation model with coupled aerosol microphysics are used to assess the influence of season of eruption on the aerosol evolution and radiative impacts at the Earth's surface. This analysis is presented for eruptions with SO2 injection magnitudes of 17 and 700 Tg, the former consistent with estimates of the 1991 Mt. Pinatubo eruption, the later a near-"super eruption". For each eruption magnitude, simulations are performed with eruptions at 15° N, at four equally spaced times of year, and sensitivity to eruption season is quantified as the difference between the maximum and minimum cumulative anomalies.

    Eruption season has a significant influence on aerosol optical depth (AOD and clear-sky shortwave (SW radiative flux anomalies for both eruption magnitudes. The sensitivity to eruption season for both fields is generally weak in the tropics, but increases in the mid- and high latitudes, reaching maximum values of ~80 %. Global mean AOD and clear-sky SW anomalies show sensitivity to eruption season on the order of 15–20 %, which results from differences in aerosol effective radius for the different eruption seasons. Smallest aerosol size and largest cumulative impact result from a January eruption for the Pinatubo-magnitude, and from a July eruption for the near-super eruption. In contrast to AOD and clear-sky SW anomalies, all-sky SW anomalies are found to be insensitive to season of eruption for the Pinatubo-magnitude eruption experiment, due to the reflection of solar radiation by clouds in the mid- to high latitudes. However, differences in all-sky SW anomalies between eruptions in different seasons are significant for the larger eruption magnitude, and the ~15 % sensitivity to eruption season of the global mean all-sky SW anomalies is comparable to the sensitivity of global mean AOD and clear-sky SW anomalies. Our estimates of sensitivity to eruption season

  12. Literature Review and Global Consensus on Management of Acute Radiation Syndrome Affecting Nonhematopoietic Organ Systems

    Science.gov (United States)

    Dainiak, Nicholas; Gent, Robert Nicolas; Carr, Zhanat; Schneider, Rita; Bader, Judith; Buglova, Elena; Chao, Nelson; Coleman, C. Norman; Ganser, Arnold; Gorin, Claude; Hauer-Jensen, Martin; Huff, L. Andrew; Lillis-Hearne, Patricia; Maekawa, Kazuhiko; Nemhauser, Jeffrey; Powles, Ray; Schünemann, Holger; Shapiro, Alla; Stenke, Leif; Valverde, Nelson; Weinstock, David; White, Douglas; Albanese, Joseph; Meineke, Viktor

    2013-01-01

    Objectives The World Health Organization convened a panel of experts to rank the evidence for medical countermeasures for management of acute radiation syndrome (ARS) in a hypothetical scenario involving the hospitalization of 100 to 200 victims. The goal of this panel was to achieve consensus on optimal management of ARS affecting nonhematopoietic organ systems based upon evidence in the published literature. Methods English-language articles were identified in MEDLINE and PubMed. Reference lists of retrieved articles were distributed to conferees in advance of and updated during the meeting. Published case series and case reports of ARS, publications of randomized controlled trials of relevant interventions used to treat nonirradiated individuals, reports of studies in irradiated animals, and prior recommendations of subject matter experts were selected. Studies were extracted using the Grading of Recommendations Assessment Development and Evaluation system. In cases in which data were limited or incomplete, a narrative review of the observations was made. Results No randomized controlled trials of medical countermeasures have been completed for individuals with ARS. Reports of countermeasures were often incompletely described, making it necessary to rely on data generated in nonirradiated humans and in experimental animals. A strong recommendation is made for the administration of a serotonin-receptor antagonist prophylactically when the suspected exposure is >2 Gy and topical steroids, antibiotics, and antihistamines for radiation burns, ulcers, or blisters; excision and grafting of radiation ulcers or necrosis with intractable pain; provision of supportive care to individuals with neurovascular syndrome; and administration of electrolyte replacement therapy and sedatives to individuals with significant burns, hypovolemia, and/ orshock. A strong recommendation is made against the use of systemic steroids in the absence of a specific indication. A weak

  13. Tension between reducing sea-level rise and global warming through solar-radiation management

    Science.gov (United States)

    Irvine, P. J.; Sriver, R. L.; Keller, K.

    2012-02-01

    Geoengineering using solar-radiation management (SRM) is gaining interest as a potential strategy to reduce future climate change impacts. Basic physics and past observations suggest that reducing insolation will, on average, cool the Earth. It is uncertain, however, whether SRM can reduce climate change stressors such as sea-level rise or rates of surface air temperature change. Here we use an Earth system model of intermediate complexity to quantify the possible response of sea levels and surface air temperatures to projected climate forcings and SRM strategies. We find that SRM strategies introduce a potentially strong tension between the objectives to reduce (1) the rate of temperature change and (2) sea-level rise. This tension arises primarily because surface air temperatures respond faster to radiative forcings than sea levels. Our results show that the forcing required to stop sea-level rise could cause a rapid cooling with a rate similar to the peak business-as-usual warming rate. Furthermore, termination of SRM was found to produce warming rates up to five times greater than the maximum rates under the business-as-usual CO2 scenario, whereas sea-level rise rates were only 30% higher. Reducing these risks requires a slow phase-out of many decades and thus commits future generations.

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

    Science.gov (United States)

    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.

  15. Global model simulations of the impact of ocean-going ships on aerosols, clouds, and the radiation budget

    Directory of Open Access Journals (Sweden)

    A. Lauer

    2007-07-01

    Full Text Available International shipping contributes significantly to the fuel consumption of all transport related activities. Specific emissions of pollutants such as sulfur dioxide (SO2 per kg of fuel emitted are higher than for road transport or aviation. Besides gaseous pollutants, ships also emit various types of particulate matter. The aerosol impacts the Earth's radiation budget directly by scattering and absorbing incoming solar radiation and indirectly by changing cloud properties. Here we use ECHAM5/MESSy1-MADE, a global climate model with detailed aerosol and cloud microphysics, to show that emissions from ships significantly increase the cloud droplet number concentration of low maritime water clouds. Whereas the cloud liquid water content remains nearly unchanged in these simulations, effective radii of cloud droplets decrease, leading to cloud optical thickness increase up to 5–10%. The sensitivity of the results is estimated by using three different emission inventories for present day conditions. The sensitivity analysis reveals that shipping contributes with 2.3% to 3.6% to the total sulfate burden and 0.4% to 1.4% to the total black carbon burden in the year 2000. In addition to changes in aerosol chemical composition, shipping increases the aerosol number concentration, e.g. up to 25% in the size range of the accumulation mode (typically >0.1 μm over the Atlantic. The total aerosol optical thickness over the Indian Ocean, the Gulf of Mexico and the Northeastern Pacific increases up to 8–10% depending on the emission inventory. Changes in aerosol optical thickness caused by the shipping induced modification of aerosol particle number concentration and chemical composition lead to a change of the net top of the atmosphere (ToA clear sky radiation of about −0.013 W/m2 to −0.036 W/m2 on global annual average. The estimated all-sky direct aerosol effect calculated from these changes ranges between −0

  16. Long-Term Variations of the Electron Slot Region and Global Radiation Belt Structure

    Science.gov (United States)

    Fung, Shing F.; Shao, Xi; Tan, Lun C.

    2005-01-01

    We report the observations of changes of the nominal position of the quiet-time radiation belt slot over the solar cycles. It has been found that the slot region, believed to be a result of enhanced precipitation losses of energetic electrons due to their interactions with VLF waves in the magnetosphere, tends to shift to higher L (approximately 3) during a solar maximum compared to its canonical L value of approximately 2.5, which is more typical of a solar minimum. The solar-cycle migration of the slot can be understood in terms of the solar-cycle changes in ionospheric densities, which may cause the optimal wave-particle interaction region during higher solar activity periods to move to higher altitudes and higher latitudes, thus higher L. Our analysis also suggests that the primary wave-particle interaction processes that result in the slot formation are located off of the magnetic equator.

  17. Establishing a Global Radiation Oncology Collaboration in Education (GRaCE)

    DEFF Research Database (Denmark)

    Turner, Sandra; Eriksen, Jesper G; Trotter, Theresa;

    2015-01-01

    from the ESTRO School, encompassing many European countries adopting the ESTRO Core Curriculum, and clinician educators from Canada, Denmark, the United Kingdom, Australia and New Zealand considered the training and educational arrangements within their jurisdictions, identifying similarities......Representatives from countries and regions world-wide who have implemented modern competency-based radiation- or clinical oncology curricula for training medical specialists, met to determine the feasibility and value of an ongoing international collaboration. In this forum, educational leaders...... and challenges between programs. Common areas of educational interest and need were defined, which included development of new competency statements and assessment tools, and the application of the latter. The group concluded that such an international cooperation, which might expand to include others...

  18. The UK Met Office global circulation model with a sophisticated radiation scheme applied to the hot Jupiter HD 209458b

    Science.gov (United States)

    Amundsen, David S.; Mayne, Nathan J.; Baraffe, Isabelle; Manners, James; Tremblin, Pascal; Drummond, Benjamin; Smith, Chris; Acreman, David M.; Homeier, Derek

    2016-10-01

    To study the complexity of hot Jupiter atmospheres revealed by observations of increasing quality, we have adapted the UK Met Office Global Circulation Model (GCM), the Unified Model (UM), to these exoplanets. The UM solves the full 3D Navier-Stokes equations with a height-varying gravity, avoiding the simplifications used in most GCMs currently applied to exoplanets. In this work we present the coupling of the UM dynamical core to an accurate radiation scheme based on the two-stream approximation and correlated-k method with state-of-the-art opacities from ExoMol. Our first application of this model is devoted to the extensively studied hot Jupiter HD 209458b. We have derived synthetic emission spectra and phase curves, and compare them to both previous models also based on state-of-the-art radiative transfer, and to observations. We find a reasonable agreement between observations and both our days side emission and hot spot offset, however, our night side emissions is too large. Overall our results are qualitatively similar to those found by Showman et al. (2009, ApJ, 699, 564) with the SPARC/MITgcm, however, we note several quantitative differences: Our simulations show significant variation in the position of the hottest part of the atmosphere with pressure, as expected from simple timescale arguments, and in contrast to the "vertical coherency" found by Showman et al. (2009). We also see significant quantitative differences in calculated synthetic observations. Our comparisons strengthen the need for detailed intercomparisons of dynamical cores, radiation schemes and post-processing tools to understand these differences. This effort is necessary in order to make robust conclusions about these atmospheres based on GCM results.

  19. Global simulations of axisymmetric radiative black hole accretion discs in general relativity with a mean-field magnetic dynamo

    Science.gov (United States)

    Sądowski, Aleksander; Narayan, Ramesh; Tchekhovskoy, Alexander; Abarca, David; Zhu, Yucong; McKinney, Jonathan C.

    2015-02-01

    We present a mean-field model that emulates the magnetic dynamo operating in magnetized accretion discs. We have implemented this model in the general relativisic radiation magnetohydrodynamic (GRRMHD) code KORAL, using results from local shearing sheet simulations of the magnetorotational instability to fix the parameters of the dynamo. With the inclusion of this dynamo, we are able to run 2D axisymmetric GRRMHD simulations of accretion discs for arbitrarily long times. The simulated discs exhibit sustained turbulence, with the poloidal and toroidal magnetic field components driven towards a state similar to that seen in 3D studies. Using this dynamo code, we present a set of long-duration global simulations of super-Eddington, optically thick discs around non-spinning and spinning black holes. Super-Eddington discs around non-rotating black holes exhibit a surprisingly large efficiency, η ≈ 0.04, independent of the accretion rate, where we measure efficiency in terms of the total energy output, both radiation and mechanical, flowing out to infinity. This value significantly exceeds the efficiency predicted by slim disc models for these accretion rates. Super-Eddington discs around spinning black holes are even more efficient, and appear to extract black hole rotational energy through a process similar to the Blandford-Znajek mechanism. All the simulated models are characterized by highly super-Eddington radiative fluxes collimated along the rotation axis. We also present a set of simulations that were designed to have Eddington or slightly sub-Eddington accretion rates (dot{M} ≲ 2dot{M}_Edd). None of these models reached a steady state. Instead, the discs collapsed as a result of runaway cooling, presumably because of a thermal instability.

  20. Development of Multi-Sensor Global Cloud and Radiance Composites for Earth Radiation Budget Monitoring from DSCOVR

    Science.gov (United States)

    Khlopenkov, Konstantin; Duda, David; Thieman, Mandana; Minnis, Patrick; Su, Wenying; Bedka, Kristopher

    2017-01-01

    The Deep Space Climate Observatory (DSCOVR) enables analysis of the daytime Earth radiation budget via the onboard Earth Polychromatic Imaging Camera (EPIC) and National Institute of Standards and Technology Advanced Radiometer (NISTAR). Radiance observations and cloud property retrievals from low earth orbit and geostationary satellite imagers have to be co-located with EPIC pixels to provide scene identification in order to select anisotropic directional models needed to calculate shortwave and longwave fluxes. A new algorithm is proposed for optimal merging of selected radiances and cloud properties derived from multiple satellite imagers to obtain seamless global hourly composites at 5-kilometer resolution. An aggregated rating is employed to incorporate several factors and to select the best observation at the time nearest to the EPIC measurement. Spatial accuracy is improved using inverse mapping with gradient search during reprojection and bicubic interpolation for pixel resampling. The composite data are subsequently remapped into EPIC-view domain by convolving composite pixels with the EPIC point spread function (PSF) defined with a half-pixel accuracy. PSF-weighted average radiances and cloud properties are computed separately for each cloud phase. The algorithm has demonstrated contiguous global coverage for any requested time of day with a temporal lag of under 2 hours in over 95 percent of the globe.

  1. Estimativa da radiação solar global a partir dos dados de insolação, para Santa Maria - RS Estimation of global radiation from insolation data for Santa Maria, RS, Brazil

    Directory of Open Access Journals (Sweden)

    Galileo Adeli Buriol

    2012-09-01

    Full Text Available Foram determinados os coeficientes a e b da equação de Angströn-Prescott para a estimativa da radiação solar global para Santa Maria, RS. Utilizaram-se os dados diários da intensidade de fluxo de radiação solar global e de insolação (brilho solar registrados na Estação Meteorológica pertencente ao 8° Distrito de Meteorologia, localizada no Campus da Universidade Federal de Santa Maria - UFSM, período 2002-2008. Os dados foram copiados no banco de dados do 8° Distrito de Meteorologia - 8° DISME, em Porto Alegre, e calculados os valores diários de radiação solar global no topo da atmosfera e de insolação máxima possível, considerando a latitude local. Com esses dados, foram determinadas as equações mensais e estacionais de regressão para a estimativa da radiação solar global em função da insolação. Constatou-se que existe alta correlação entre os dados de radiação solar global com aqueles de insolação, sendo, assim, possível estimar a radiação solar global em função da insolação.Coefficients a and b of the Angströn - Prescott equation to estimate global solar radiation for Santa Maria, RS were determined. Daily data of global solar radiation and sunshine, were obtained from the Meteorological Station which belongs to the 8th District of Meteorology, located on the campus of the Federal University of Santa Maria - UFSM, period from 2002 to 2008. The mentioned data were copied from the database of the 8th District of Meteorology - 8th DISME in Porto Alegre. Top of atmosphere radiation and possible maximum sunshine were calculated considering local latitude. With such elements, monthly regression equations were determined for the estimation of solar radiation as a function of insolation. We found a high correlation between insolation and global solar radiation and it's possible to estimate the solar radiation depending on the measured insolation.

  2. Mechanisms of Formation of Secondary Organic Aerosols and Implications for Global Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Seinfeld, John H. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2011-12-02

    Organic material constitutes about 50% of global atmospheric aerosol mass, and the dominant source of organic aerosol is the oxidation of volatile hydrocarbons, to produce secondary organic aerosol (SOA). Understanding the formation of SOA is crucial to predicting present and future climate effects of atmospheric aerosols. The goal of this program is to significantly increase our understanding of secondary organic aerosol (SOA) formation in the atmosphere. Ambient measurements indicate that the amount of SOA in the atmosphere exceeds that predicted in current models based on existing laboratory chamber data. This would suggest that either the SOA yields measured in laboratory chambers are understated or that all major organic precursors have not been identified. In this research program we are systematically exploring these possibilities.

  3. Impacts of global open-fire aerosols on direct radiative, cloud and surface-albedo effects simulated with CAM5

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yiquan; Lu, Zheng; Liu, Xiaohong; Qian, Yun; Zhang, Kai; Wang, Yuhang; Yang, Xiu-Qun

    2016-11-29

    Aerosols from open-land fires could significantly perturb the global radiation balance and induce climate change. In this study, Community Atmosphere Model version 5 (CAM5) with prescribed daily fire aerosol emissions is used to investigate the spatial and seasonal characteristics of radiative effects (REs, relative to the case of no fires) of open-fire aerosols including black carbon (BC) and particulate organic matter (POM) from 2003 to 2011. The global annual mean RE from aerosol–radiation interactions (REari) of all fire aerosols is 0.16 ± 0.01 W m-2 (1σ uncertainty), mainly due to the absorption of fire BC (0.25 ± 0.01 W m-2), while fire POM induces a small effect (-0.05 and 0.04 ± 0.01 W m-2 based on two different methods). Strong positive REari is found in the Arctic and in the oceanic regions west of southern Africa and South America as a result of amplified absorption of fire BC above low-level clouds, in general agreement with satellite observations. The global annual mean RE due to aerosol–cloud interactions (REaci) of all fire aerosols is -0.70 ± 0.05 W m-2, resulting mainly from the fire POM effect (-0.59 ± 0.03 W m-2). REari (0.43 ± 0.03 W m-2) and REaci (-1.38 ± 0.23 W m-2) in the Arctic are stronger than in the tropics (0.17 ± 0.02 and -0.82 ± 0.09 W m-2 for REari and REaci), although the fire aerosol burden is higher in the tropics. The large cloud liquid water path over land areas and low solar zenith angle of the Arctic favor the strong fire aerosol REaci (up to -15 Wm-2) during the Arctic summer. Significant surface cooling, precipitation reduction and increasing amounts of low-level cloud are also found in the Arctic summer as a result of the fire aerosol REaci based on the atmosphere-only simulations. The global annual mean RE due to surface-albedo changes (REsac) over land areas (0.03 ± 0.10 W m-2) is small

  4. Comparison of 37 months global net radiation flux derived from PICARD-BOS over the same period observations of CERES and ARGO

    Science.gov (United States)

    Zhu, Ping; Wild, Martin

    2016-04-01

    The absolute level of the global net radiation flux (NRF) is fixed at the level of [0.5-1.0] Wm-2 based on the ocean heat content measurements [1]. The space derived global NRF is at the same order of magnitude than the ocean [2]. Considering the atmosphere has a negligible effects on the global NRF determination, the surface global NRF is consistent with the values determined from space [3]. Instead of studying the absolute level of the global NRF, we focus on the interannual variation of global net radiation flux, which were derived from the PICARD-BOS experiment and its comparison with values over the same period but obtained from the NASA-CERES system and inferred from the ocean heat content survey by ARGO network. [1] Allan, Richard P., Chunlei Liu, Norman G. Loeb, Matthew D. Palmer, Malcolm Roberts, Doug Smith, and Pier-Luigi Vidale (2014), Changes in global net radiative imbalance 1985-2012, Geophysical Research Letters, 41 (no.15), 5588-5597. [2] Loeb, Norman G., John M. Lyman, Gregory C. Johnson, Richard P. Allan, David R. Doelling, Takmeng Wong, Brian J. Soden, and Graeme L. Stephens (2012), Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty, Nature Geoscience, 5 (no.2), 110-113. [3] Wild, Martin, Doris Folini, Maria Z. Hakuba, Christoph Schar, Sonia I. Seneviratne, Seiji Kato, David Rutan, Christof Ammann, Eric F. Wood, and Gert Konig-Langlo (2015), the energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models, Climate Dynamics, 44 (no.11-12), 3393-3429.

  5. Quantitative Evaluation of MODIS Fire Radiative Power Measurement for Global Smoke Emissions Assessment

    Science.gov (United States)

    Ichoku, Charles; Ellison, Luke

    2011-01-01

    Satellite remote sensing is providing us tremendous opportunities to measure the fire radiative energy (FRE) release rate or power (FRP) from open biomass burning, which affects many vegetated regions of the world on a seasonal basis. Knowledge of the biomass burning characteristics and emission source strengths of different (particulate and gaseous) smoke constituents is one of the principal ingredients upon which the assessment, modeling, and forecasting of their distribution and impacts depend. This knowledge can be gained through accurate measurement of FRP, which has been shown to have a direct relationship with the rates of biomass consumption and emissions of major smoke constituents. Over the last decade or so, FRP has been routinely measured from space by both the MODIS sensors aboard the polar orbiting Terra and Aqua satellites, and the SEVIRI sensor aboard the Meteosat Second Generation (MSG) geostationary satellite. During the last few years, FRP has steadily gained increasing recognition as an important parameter for facilitating the development of various scientific studies and applications relating to the quantitative characterization of biomass burning and their emissions. To establish the scientific integrity of the FRP as a stable quantity that can be measured consistently across a variety of sensors and platforms, with the potential of being utilized to develop a unified long-term climate data record of fire activity and impacts, it needs to be thoroughly evaluated, calibrated, and validated. Therefore, we are conducting a detailed analysis of the FRP products from MODIS to evaluate the uncertainties associated with them, such as those due to the effects of satellite variable observation geometry and other factors, in order to establish their error budget for use in diverse scientific research and applications. In this presentation, we will show recent results of the MODIS FRP uncertainty analysis and error mitigation solutions, and demonstrate

  6. Evaluation of artificial neural network (ANN and adaptive neuro-fuzzy inference system (ANFIS methods in prediction of global solar radiation

    Directory of Open Access Journals (Sweden)

    AA Sabziparvar

    2011-03-01

    Full Text Available Solar radiation is an important climate parameter which can affect hydrological and meteorological processes. This parameter is a key element in development of solar energy application studies. The purpose of this study is the assessment of artificial intelligence techniques in prediction of solar radiation (Rs using artificial neural network (ANN and adaptive neuro-fuzzy inference system (ANFIS. Minimum temperature, maximum temperature, average relative humidity, sunshine hours and daily solar radiation recorded in four synoptic stations (Esfahan, Urmieh, Shiraz and Kerman were used during the period 1992-2006. The results showed that ANN and ANFIS intelligent models are powerful tools in prediction of global solar radiation for the selected stations. Prediction by ANN was found to be more accurate than ANFIS. Also, the accuracy of prediction in Kerman with higher sunny hours was better than other stations (R2> 0.9. Additionally, using linear regression model, the most effective factors affecting Rs in each site was introduced. The results revealed that sunshine hour is the most important determining parameter affecting surface solar radiation. In contrast, in most sites minimum air temperature and mean relative humidity showed the least effect on surface global solar radiation.

  7. CH3Cl, CH2Cl2, CHCl3, and CCl4: Infrared spectra, radiative efficiencies, and global warming potentials

    Science.gov (United States)

    Wallington, Timothy J.; Pivesso, Bruno Pasquini; Lira, Alane Moura; Anderson, James E.; Nielsen, Claus Jørgen; Andersen, Niels Højmark; Hodnebrog, Øivind

    2016-05-01

    Infrared spectra for the title compounds were measured experimentally in 700 Torr of air at 295 K and systematically modeled in B3LYP, M06-2X and MP2 calculations employing various basis sets. Calibrated infrared spectra over the wavenumber range 600-3500 cm-1 are reported and combined with literature data to provide spectra for use in experimental studies and radiative transfer calculations. Integrated absorption cross sections are (units of cm-1 molecule-1): CH3Cl, 660-780 cm-1, (3.89±0.19)×10-18; CH2Cl2, 650-800 cm-1, (2.16±0.11)×10-17; CHCl3, 720-810 cm-1, (4.08±0.20)×10-17; and CCl4, 730-825 cm-1, (6.30±0.31)×10-17. CH3Cl, CH2Cl2, CHCl3, and CCl4 have radiative efficiencies of 0.004, 0.028, 0.070, and 0.174 W m-2 ppb-1 and global warming potentials (100 year horizon) of 5, 8, 15, and 1775, respectively. Quantum chemistry calculations generally predict larger band intensities than the experimental values. The best agreement with experiments is obtained in MP2(Full) calculations employing basis sets of at least triple-zeta quality augmented by diffuse functions. The B3LYP functional is found ill-suited for calculating vibrational frequencies and infrared intensities of halocarbons.

  8. Shortwave direct radiative effects of above cloud aerosols over global oceans derived from eight years of CALIOP and MODIS observations

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2015-09-01

    Full Text Available In this paper, we studied the frequency of occurrence and shortwave direct radiative effects (DRE of above-cloud aerosols (ACAs over global oceans using eight years of collocated CALIOP and MODIS observations. Similar to previous work, we found high ACA occurrence in four regions: Southeast (SE Atlantic region where ACAs are mostly light-absorbing aerosols, i.e., smoke and polluted dust according to CALIOP classification, originating from biomass burning over African Savanna; Tropical Northeast Atlantic and Arabian Sea where ACAs are predominantly windblown dust from the Sahara and Arabian desert, respectively; and Northwest Pacific where ACAs are mostly transported smoke and polluted dusts from Asian. From radiative transfer simulations based on CALIOP-MODIS observations and a set of the preselected aerosol optical models, we found the DREs of ACAs at the top of atmosphere (TOA to be positive (i.e., warming in the SE Atlantic and NW Pacific regions, but negative (i.e., cooling in TNE Atlantic and Arabian Sea. The cancellation of positive and negative regional DREs results in a global ocean annual mean diurnally averaged cloudy-sky DRE of 0.015 W m−2 (range of −0.03 to 0.06 W m−2 at TOA. The DREs at surface and within atmosphere are −0.15 W m−2 (range of −0.09 to −0.21 W m−2, and 0.17 W m−2 (range of 0.11 to 0.24 W m−2, respectively. The regional and seasonal mean DREs are much stronger. For example, in the SE Atlantic region the JJA (July ~ August seasonal mean cloudy-sky DRE is about 0.7 W m−2 (range of 0.2 to 1.2 W m−2 at TOA. The uncertainty in our DRE computations is mainly cause by the uncertainties in the aerosol optical properties, in particular aerosol absorption, and uncertainties in the CALIOP operational aerosol optical thickness retrieval. In situ and remotely sensed measurements of ACA from future field campaigns and satellite missions, and improved lidar retrieval algorithm, in particular vertical feature

  9. Shortwave direct radiative effects of above cloud aerosols over global oceans derived from eight years of CALIOP and MODIS observations

    Science.gov (United States)

    Zhang, Z.; Meyer, K.; Yu, H.; Platnick, S.; Colarco, P.; Liu, Z.; Oreopoulos, L.

    2015-09-01

    In this paper, we studied the frequency of occurrence and shortwave direct radiative effects (DRE) of above-cloud aerosols (ACAs) over global oceans using eight years of collocated CALIOP and MODIS observations. Similar to previous work, we found high ACA occurrence in four regions: Southeast (SE) Atlantic region where ACAs are mostly light-absorbing aerosols, i.e., smoke and polluted dust according to CALIOP classification, originating from biomass burning over African Savanna; Tropical Northeast Atlantic and Arabian Sea where ACAs are predominantly windblown dust from the Sahara and Arabian desert, respectively; and Northwest Pacific where ACAs are mostly transported smoke and polluted dusts from Asian. From radiative transfer simulations based on CALIOP-MODIS observations and a set of the preselected aerosol optical models, we found the DREs of ACAs at the top of atmosphere (TOA) to be positive (i.e., warming) in the SE Atlantic and NW Pacific regions, but negative (i.e., cooling) in TNE Atlantic and Arabian Sea. The cancellation of positive and negative regional DREs results in a global ocean annual mean diurnally averaged cloudy-sky DRE of 0.015 W m-2 (range of -0.03 to 0.06 W m-2) at TOA. The DREs at surface and within atmosphere are -0.15 W m-2 (range of -0.09 to -0.21 W m-2), and 0.17 W m-2 (range of 0.11 to 0.24 W m-2), respectively. The regional and seasonal mean DREs are much stronger. For example, in the SE Atlantic region the JJA (July ~ August) seasonal mean cloudy-sky DRE is about 0.7 W m-2 (range of 0.2 to 1.2 W m-2) at TOA. The uncertainty in our DRE computations is mainly cause by the uncertainties in the aerosol optical properties, in particular aerosol absorption, and uncertainties in the CALIOP operational aerosol optical thickness retrieval. In situ and remotely sensed measurements of ACA from future field campaigns and satellite missions, and improved lidar retrieval algorithm, in particular vertical feature masking, would help reduce the

  10. Variability and trends of downward surface global solar radiation over the Iberian Peninsula based on ERA-40 reanalysis

    KAUST Repository

    Perdigão, João Carlos

    2016-01-26

    © 2016 Royal Meteorological Society. A climate study of the incidence of downward surface global solar radiation (SSRD) in the Iberian Peninsula (IP) based primarily on ERA-40 reanalysis is presented. NCEP/NCAR reanalysis and ground-based records from several Portuguese and Spanish stations have been also considered. The results show that reanalysis can capture a similar inter-annual variability as compared to ground-based observations, especially on a monthly basis, even though annual ERA-40 (NCEP/NCAR) values tend to underestimate (overestimate) the observations with a mean relative difference of around 20Wm-2 (40Wm-2). On the other hand, ground-based measurements in Portuguese stations during the period 1964-1989 show a tendency to decrease until the mid-1970s followed by an increase up to the end of the study period, in line with the dimming/brightening phenomenon reported in the literature. Nevertheless, there are different temporal behaviours as a greater increase since the 1970s is observed in the south and less industrialized regions. Similarly, the ERA-40 reanalysis shows a noticeable decrease until the early 1970s followed by a slight increase up to the end of the 1990s, suggesting a dimming/brightening transition around the early 1970s, earlier in the south and centre and later in the north of the IP. Although there are slight differences in the magnitude of the trends as well as the turning year of the dimming/brightening periods, the decadal changes of ERA-40 fairly agree with the ground-based observations in Portugal and Spain, in contrast to most of the literature for other regions of the world, and is used in the climatology of the SSRD in the study area. NCEP/NCAR reanalysis does not capture the decadal variations of SSRD in the IP. The results show that part of the decadal variability of the global radiation in the IP is related to changes in cloud cover (represented in ERA-40).

  11. Estimation of global solar radiation using an artificial neural network based on an interpolation technique in southeast China

    Science.gov (United States)

    Zou, Ling; Wang, Lunche; Lin, Aiwen; Zhu, Hongji; Peng, Yuling; Zhao, Zhenzhen

    2016-08-01

    Solar radiation plays important roles in energy application, vegetation growth and climate change. Empirical relations and machine-learning methods have been widely used to estimate global solar radiation (GSR) in recent years. An artificial neural network (ANN) based on spatial interpolation is developed to estimate GSR in southeast China. The improved Bristow-Campbell (IBC) model and the improved Ångström-Prescott (IA-P) model are compared with the ANN model to explore the best model in solar radiation modeling. Daily meteorological parameters, such as sunshine duration hours, mean temperature, maximum temperature, minimum temperature, relative humidity, precipitation, air pressure, water vapor pressure, and wind speed, along with station-measured GSR and a daily surface GSR dataset over China obtained from the Data Assimilation and Modeling Center for Tibetan Multi-spheres (DAM), are used to predict GSR and to validate the models in this work. The ANN model with the network of 9-17-1 provides better accuracy than the two improved empirical models in GSR estimation. The root-mean-square error (RMSE), mean bias error (MBE), and determination coefficient (R2) are 2.65 MJ m-2, -0.94 MJ m-2, and 0.68 in the IA-P model; 2.19 MJ m-2, 1.11 MJ m-2, and 0.83 in the IBC model; 1.34 MJ m-2, -0.11 MJ m-2, and 0.91 in the ANN model, respectively. The regional monthly mean GSR in the measured dataset, DAM dataset, and ANN model is analyzed. The RMSE (RMSE %) is 1.07 MJ m-2 (8.91%) and the MBE (MBE %) is -0.62 MJ m-2 (-5.21%) between the measured and ANN-estimated GSR. The statistical errors of RMSE (RMSE %) are 0.91 MJ m-2 (7.28%) and those of MBE (MBE %) are -0.15 MJ m-2 (-1.20%) between DAM and ANN-modeled GSR. The correlation coefficients and R2 are larger than 0.95. The regional mean GSR is 12.58 MJ m-2. The lowest GSR is observed in the northwest area, and it increases from northwest to southeast. The annual mean GSR decreases by 0.02 MJ m-2 decade-1 over the entire

  12. ANFIS, SVM and ANN soft-computing techniques to estimate daily global solar radiation in a warm sub-humid environment

    Science.gov (United States)

    Quej, Victor H.; Almorox, Javier; Arnaldo, Javier A.; Saito, Laurel

    2017-03-01

    Daily solar radiation is an important variable in many models. In this paper, the accuracy and performance of three soft computing techniques (i.e., adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN) and support vector machine (SVM) were assessed for predicting daily horizontal global solar radiation from measured meteorological variables in the Yucatán Peninsula, México. Model performance was assessed with statistical indicators such as root mean squared error (RMSE), mean absolute error (MAE) and coefficient of determination (R2). The performance assessment indicates that the SVM technique with requirements of daily maximum and minimum air temperature, extraterrestrial solar radiation and rainfall has better performance than the other techniques and may be a promising alternative to the usual approaches for predicting solar radiation.

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

    Science.gov (United States)

    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.

  14. A global model simulation of present and future nitrate aerosols and their direct radiative forcing of climate

    Directory of Open Access Journals (Sweden)

    D. A. Hauglustaine

    2014-03-01

    Full Text Available The ammonia cycle and nitrate particle formation have been introduced in the LMDz-INCA global model. Both fine nitrate particles formation in the accumulation mode and coarse nitrate forming on existing dust and sea-salt particles are considered. The model simulates distributions of nitrates and related species in agreement with previous studies and observations. The calculated present-day total nitrate direct radiative forcing since the pre-industrial is −0.056 W m−2. This forcing has the same magnitude than the forcing associated with organic carbon particles and represents 18% of the sulfate forcing. Fine particles largely dominate the nitrate forcing representing close to 90% of this value. The model has been used to investigate the future changes in nitrates and direct radiative forcing of climate based on snapshot simulations for the four Representative Concentration Pathway (RCP scenarios and for the 2030, 2050 and 2100 time horizons. Due to a decrease in fossil fuel emissions in the future, the concentrations of most of the species involved in the nitrate-ammonium-sulfate system drop by 2100 except for ammonia which originates from agricultural practices and for which emissions significantly increase in the future. Despite the decrease of nitrate surface levels in Europe and Northern America, the global burden of accumulation mode nitrates increases by up to a factor of 2.6 in 2100. This increase in nitrate in the future arises despite decreasing NOx emissions due to increased availability of ammonia to form ammonium nitrate. The total aerosol direct forcing decreases from its present-day value of −0.234 W m−2 to a range of −0.070 to −0.130 W m−2 in 2100 based on the considered scenario. The direct forcing decreases for all aerosols except for nitrates for which the direct negative forcing increases to a range of −0.060 to −0.115 W m−2 in 2100. Including nitrates in the radiative forcing calculations increases the

  15. A global model simulation of present and future nitrate aerosols and their direct radiative forcing of climate

    Science.gov (United States)

    Hauglustaine, D. A.; Balkanski, Y.; Schulz, M.

    2014-10-01

    The ammonia cycle and nitrate particle formation are introduced into the LMDz-INCA (Laboratoire de Météorologie Dynamique, version 4 - INteraction with Chemistry and Aerosols, version 3) global model. An important aspect of this new model is that both fine nitrate particle formation in the accumulation mode and coarse nitrate forming on existing dust and sea-salt particles are considered. The model simulates distributions of nitrates and related species in agreement with previous studies and observations. The calculated present-day total nitrate direct radiative forcing since the pre-industrial is -0.056 W m-2. This forcing corresponds to 18% of the sulfate forcing. Fine particles largely dominate the nitrate forcing, representing close to 90% of this value. The model has been used to investigate the future changes in nitrates and direct radiative forcing of climate based on snapshot simulations for the four representative concentration pathway (RCP) scenarios and for the 2030, 2050, and 2100 time horizons. Due to a decrease in fossil fuel emissions in the future, the concentration of most of the species involved in the nitrate-ammonium-sulfate system drop by 2100 except for ammonia, which originates from agricultural practices and for which emissions significantly increase in the future. Despite the decrease of nitrate surface levels in Europe and North America, the global burden of accumulation mode nitrates increases by up to a factor of 2.6 in 2100. This increase in ammonium nitrate in the future arises despite decreasing NOx emissions due to increased availability of ammonia to form ammonium nitrate. The total aerosol direct forcing decreases from its present-day value of -0.234 W m-2 to a range of -0.070 to -0.130 W m-2 in 2100 based on the considered scenario. The direct forcing decreases for all aerosols except for nitrates, for which the direct negative forcing increases to a range of -0.060 to -0.115 W m-2 in 2100. Including nitrates in the radiative

  16. A study of uncertainties in the sulfate distribution and its radiative forcing associated with sulfur chemistry in a global aerosol model

    Directory of Open Access Journals (Sweden)

    D. Goto

    2011-04-01

    Full Text Available The direct radiative forcing by sulfate aerosols is still uncertain, mainly because the uncertainties are largely derived from differences in sulfate column burdens and its vertical distributions among global aerosol models. One of possible reasons of the large difference in the computed values is that the radiative forcing delicately depends on various simplifications of the sulfur processes made in the models. In this study, therefore, we investigated impacts of different parts of the sulfur chemistry module in a global aerosol model, SPRINTARS, on the sulfate distribution and its radiative forcing. Important studies were effects of simplified and more physical-based sulfur processes in terms of treatment of sulfur chemistry, oxidant chemistry, and dry deposition process of sulfur components. The results showed that the difference in the aqueous-phase sulfur chemistry among these treatments has the largest impact on the sulfate distribution. Introduction of all the improvements mentioned above brought the model values noticeably closer to in-situ measurements than those in the simplified methods used in the original SPRINTARS model. At the same time, these improvements also led the computed sulfate column burdens and its vertical distributions in good agreement with other AEROCOM model values. The global annual mean radiative forcings due to aerosol direct effect of anthropogenic sulfate was thus estimated to be −0.3 W m−2, whereas the original SPRINTARS model showed −0.2 W m−2. The magnitude of the difference between original and improved methods was approximately 50% of the uncertainty among estimates by the world's global aerosol models reported by the IPCC-AR4 assessment report. Findings in the present study, therefore, may suggest that the model differences in the simplifications of the sulfur processes are still a part of the large uncertainty in their simulated radiative forcings.

  17. Comparison of two intelligent models to estimate the instantaneous global solar radiation in semi-arid climate conditions: Application in Iran

    Indian Academy of Sciences (India)

    Mostafa Zamani Mohiabadi; Mohsen Mirzaei

    2017-07-01

    Solar radiation incident on the earth’s surface is a fundamental input for many aspects of climatology, hydrology, biology, and architecture. In addition, it is an important parameter in solar energy applications. Due to the high cost of the measuring instruments of solar radiation, many researchers have suggested different empirical methods to estimate this essential parameter. In this study, with the help of fuzzy systems and neural networks, two models have been designed to estimate the instantaneous global solar radiation in Rafsanjan city which has a typical climatic conditions of semi-arid region of middle eastern countries. In fuzzy and neural network model, the inputs are the number of the given day in the year, time, ambient temperature and cloudiness, The comparison between the results of the models and the measurements, shows that the estimated global radiation is similar to the measurement; for fuzzy model, statistical indicators RMSE, MBE and t-test are 103.4367 (w/m2), 4.1169 (w/m2) and 9.1318, respectively and for ANN, they are 85.46 (w/m2), 3.08 (w/m2) and 5.41, respectively. As the results indicate, both models are able to estimate the amount of radiation well, while the neural network has a higher accuracy. The output of the modes for six other cities of Iran, with similar climate conditions, also proves the ability of the proposed models.

  18. Evaluation of the relative ability of three models, the isotropic, Klucher and Hay, to predict the global radiation on a tilted surface in Beer Sheva, Israel

    Energy Technology Data Exchange (ETDEWEB)

    Kudish, A.I. (Ben-Gurion Univ. of the Negev, Beersheba (Israel). Solar Energy Lab.); Ianetz, A. (Israel Meteorological Service, Bet Dagan (Israel). Research and Development Dept.)

    1991-01-01

    The purpose of this work was to test the relative ability of three widely used models, isotropic, Klucher and Hay, to predict the total radiation incident on a titled surface. The last two models correct the isotropic model for the inherent anisotropy present in the diffuse component of global radiation. A statistical analysis of the three models, using values of measured normal incidence beam and global radiation on a horizontal surface and on a south-facing surface inclined at 40{sup o}C at a semi-arid site, Beer Sheva, Israel (31{sup o}15'N, 34{sup o}48'E), gave the following conclusions: (i) on a yearly basis, the Hay model gives the most accurate prediction of total radiation on a tilted surface, i.e. an average RMSE value of 4.0%. (ii) from April to August, the accuracy of the isotropic model approaches that of the Hay model; (iii) from January to March and from September to December, the accuracy of the Klucher and Hay models are comparable; and (iv) based upon the results of the analysis, the simple isotropic model provides a very good first approximation of the total radiation incident on south-facing surfaces inclined up to an angle of 40{sup o}. (author).

  19. A simplified model for generating sequences of global solar radiation data for isolated sites: Using artificial neural network and a library of Markov transition matrices approach

    Energy Technology Data Exchange (ETDEWEB)

    Mellit, A. [University Center of Medea, Institute of Engineering Sciences, Department of Electronics, Ain Dahab, Mdea 26000 (Algeria); Benghanem, M. [University of Sciences Technology Houari Boumediene (USTHB), Faculty of Electrical Engineering, El-Alia, P.O. Box 32, Algiers 16111 (Algeria); Arab, A. Hadj [Development Center of Renewable Energy (CDER), P.O. Box 62, Bouzareah, Algiers 16000 (Algeria); Guessoum, A. [Faculty of Science Engineering, Department of Electronics, Blida University, Blida (Algeria)

    2005-11-01

    The purpose of this work is to develop a hybrid model which will be used to predict the daily global solar radiation data by combining between an artificial neural network (ANN) and a library of Markov transition matrices (MTM) approach. Developed model can generate a sequence of global solar radiation data using a minimum of input data (latitude, longitude and altitude), especially in isolated sites. A data base of daily global solar radiation data has been collected from 60 meteorological stations in Algeria during 1991-2000. Also a typical meteorological year (TMY) has been built from this database. Firstly, a neural network block has been trained based on 60 known monthly solar radiation data from the TMY. In this way, the network was trained to accept and even handle a number of unusual cases. The neural network can generate the monthly solar radiation data. Secondly, these data have been divided by corresponding extraterrestrial value in order to obtain the monthly clearness index values. Based on these monthly clearness indexes and using a library of MTM block we can generate the sequences of daily clearness indexes. Known data were subsequently used to investigate the accuracy of the prediction. Furthermore, the unknown validation data set produced very accurate prediction; with an RMSE error not exceeding 8% between the measured and predicted data. A correlation coefficient ranging from 90% and 92% have been obtained; also this model has been compared to the traditional models AR, ARMA, Markov chain, MTM and measured data. Results obtained indicate that the proposed model can successfully be used for the estimation of the daily solar radiation data for any locations in Algeria by using as input the altitude, the longitude, and the latitude. Also, the model can be generalized for any location in the world. An application of sizing PV systems in isolated sites has been applied in order to confirm the validity of this model. (author)

  20. Review of Annual Global Mean Energy Budget and Radiative Force%全球年平均能流与辐射强迫研究进展

    Institute of Scientific and Technical Information of China (English)

    高凤玲; 华泽钊; 陶乐仁; 崔国民

    2013-01-01

    The concept of greenhouse effect was introduced and the state of research on greenhouse effect and global warming from the point view of annual global mean energy budget and radiative forcing were described, which concluded that anthropogenic factors were the major cause for global wanning. The problems existing in the study of global warming were pointed out as high uncertainties existing in downward long-wave radiation, surface latent energy flux and aerosol radiation force in the annual global mean energy budget. It suggested that the observation and study of stratospheric water vapor and spectral composition of solar radiation should be enhanced and measures of energy conservation and emission reduction should be taken.%介绍了温室效应的概念;从全球年平均能流及辐射强迫的角度概述了当前温室效应及全球变暖的研究现状,说明人为因素是造成全球变暖的主因.对目前全球变暖研究中存在的问题讨论指出,全球年平均能流中大气向下的长波辐射和地表潜热通量以及气溶胶的辐射强迫仍存在着较大的不确定性,应该加强对平流层水蒸汽及太阳活动光谱分析的观测和研究:须采取一定的节能减排措施.

  1. Present and potential future contributions of sulfate, black and organic carbon aerosols from China to global air quality, premature mortality and radiative forcing

    Science.gov (United States)

    Saikawa, Eri; Naik, Vaishali; Horowitz, Larry W.; Liu, Junfeng; Mauzerall, Denise L.

    Aerosols are harmful to human health and have both direct and indirect effects on climate. China is a major contributor to global emissions of sulfur dioxide (SO 2), a sulfate (SO 42-) precursor, organic carbon (OC), and black carbon (BC) aerosols. Although increasingly examined, the effect of present and potential future levels of these emissions on global premature mortality and climate change has not been well quantified. Through both direct radiative effects and indirect effects on clouds, SO 42- and OC exert negative radiative forcing (cooling) while BC exerts positive forcing (warming). We analyze the effect of China's emissions of SO 2, SO 42-, OC and BC in 2000 and for three emission scenarios in 2030 on global surface aerosol concentrations, premature mortality, and radiative forcing (RF). Using global models of chemical transport (MOZART-2) and radiative transfer (GFDL RTM), and combining simulation results with gridded population data, mortality rates, and concentration-response relationships from the epidemiological literature, we estimate the contribution of Chinese aerosols to global annual premature mortality and to RF in 2000 and 2030. In 2000, we estimate these aerosols cause approximately 470 000 premature deaths in China and an additional 30 000 deaths globally. In 2030, aggressive emission controls lead to a 50% reduction in premature deaths from the 2000 level to 240 000 in China and 10 000 elsewhere, while under a high emissions scenario premature deaths increase 50% from the 2000 level to 720 000 in China and to 40 000 elsewhere. Because the negative RF from SO 42- and OC is larger than the positive forcing from BC, Chinese aerosols lead to global net direct RF of -74 mW m -2 in 2000 and between -15 and -97 mW m -2 in 2030 depending on the emissions scenario. Our analysis indicates that increased effort to reduce greenhouse gases is essential to address climate change as China's anticipated reduction of aerosols will result in the

  2. Radiative Forcing Due to Enhancements in Tropospheric Ozone and Carbonaceous Aerosols Caused by Asian Fires During Spring 2008

    Science.gov (United States)

    Natarajan, Murali; Pierce, R. Bradley; Lenzen, Allen J.; Al-Saadi, Jassim A.; Soja, Amber J.; Charlock, Thomas P.; Rose, Fred G.; Winker, David M.; Worden, John R.

    2012-01-01

    Simulations of tropospheric ozone and carbonaceous aerosol distributions, conducted with the Real-time Air Quality Modeling System (RAQMS), are used to study the effects of major outbreaks of fires that occurred in three regions of Asia, namely Thailand, Kazakhstan, and Siberia, during spring 2008. RAQMS is a global scale meteorological and chemical modeling system. Results from these simulations, averaged over April 2008, indicate that tropospheric ozone column increases by more than 10 Dobson units (DU) near the Thailand region, and by lesser amounts in the other regions due to the fires. Widespread increases in the optical depths of organic and black carbon aerosols are also noted. We have used an off-line radiative transfer model to evaluate the direct radiative forcing due to the fire-induced changes in atmospheric composition. For clear sky, the monthly averaged radiative forcing at the top of the atmosphere (TOA) is mostly negative with peak values less than -12 W/sq m occurring near the fire regions. The negative forcing represents the increased outgoing shortwave radiation caused by scattering due to carbonaceous aerosols. At high latitudes, the radiative forcing is positive due to the presence of absorbing aerosols over regions of high surface albedo. Regions of positive forcing at TOA are more pronounced under total sky conditions. The monthly averaged radiative forcing at the surface is mostly negative, and peak values of less than -30 W/sq m occur near the fire regions. Persistently large negative forcing at the surface could alter the surface energy budget and potentially weaken the hydrological cycle.

  3. Study on Earth Radiation Budget mission scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Dlhopolsky, R.; Hollmann, R.; Mueller, J.; Stuhlmann, R. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Atmosphaerenphysik

    1997-12-31

    The goal of this study is to study optimized satellite configurations for observation of the radiation balance of the earth. We present a literature survey of earth radiation budget missions and instruments. We develop a parametric tool to simulate realistic multiple satellite mission scenarios. This tool is a modular computer program which models satellite orbits and scanning operation. We use Meteosat data sampled at three hour intervals as a database to simulate atmospheric scenes. Input variables are satellite equatorial crossing time and instrument characteristics. Regional, zonal and global monthly averages of shortwave and longwave fluxes for an ideal observing system and several realistic satellite scenarios are produced. Comparisons show that the three satellite combinations which have equatorial crossing times at midmorning, noon and midafternoon provide the best shortwave monitoring. Crossing times near sunrise and sunset should be avoided for the shortwave. Longwave diurnal models are necessary over and surfaces and cloudy regions, if there are only two measurements made during daylight hours. We have found in the shortwave inversion comparison that at least 15% of the monthly regional errors can be attributed to the shortwave anisotropic models used. (orig.) 68 refs.

  4. Study of the dependence between the simultaneous wind speed and the global solar radiation measurements using the Time dependent Intrinsic Correlation method

    Science.gov (United States)

    Schmitt, F. G.; Calif, R.; Huang, Y.

    2014-12-01

    Wind and global solar radiation are complex atmospheric processes exhibiting nonstationary and nonlinear properties, involving with a high level intermittency degree on a broad range of spatial and temporal scales. It has been shown recently that the wind speed and the solar global radiation had intermittent and multiscaling statistics on mesoscales range.The emergence of electricity production units combining renewable wind and solar energy generation, need the understanding of the dependence between these two processes. The interest is to develop strategic tools in order to smooth the aggregate power output of this kind of electricity production unit.In this study, we study their multi-scale dynamics and we investigate possible correlations at different scales using a new methodology called Time Dependent Intrinsic Correlation (TDIC) based on the EMD (Emiprical Mode Decomposition) method. For that, the Time Dependent Intrinsic Correlation method is applied to simultaneous wind and global solar radiation measurements. The two time series are collected with a sampling time t=1h during five years at Guadeloupean Archipelago (French West Indies) located at 16°15'N latitude and 60°30'W longitude. After decomposition of both times series in fast and slow fluctuations with the EMD method, the Hilbert spectra are estimated for the both time series. The time evolution and the scale dependence of their correlation are determined at different time scales and for different intrinsic modes functions.

  5. Investigating the Performance of Chosen Models for the Estimation of Global Solar Radiation on Horizontal Surface - A Case Study in Terny Hdiel, Tlemcen of Algeria

    Directory of Open Access Journals (Sweden)

    Aicha Soufi

    2014-07-01

    Full Text Available Any study or application of solar energy in a given site requires a complete and detailed knowledge of the available solar resources. Hence, the aim of this work is to evaluate global solar radiation on a horizontal surface in Teny Benu-Hdiel, Tlemcen, Algeria (latitude 34° 46'60" N, longitude 1°22'0" E using measured meteorological data. The data were recorded in the period 1983 to 2005 using NASA's surface meteorology and solar energy-model. From these models, the new empirical constants have been obtained for Teny Benu-Hdiel. The selected models give very good results with the exception of second model (Quadratic model. Moreover, The results showed that the correlation of global solar radiation with sunshine hours, air temperature, relative humidity gives very accurate estimates for selected location (R2=0.997. Further to this, the global solar radiation values created for this study can be used in the designed and optimized performance of a stand-alone photovoltaic system for agricultural applications.

  6. Infrared Absorption Spectra, Radiative Efficiencies, and Global Warming Potentials of Newly-Detected Halogenated Compounds: CFC-113a, CFC-112 and HCFC-133a

    Directory of Open Access Journals (Sweden)

    Maryam Etminan

    2014-07-01

    Full Text Available CFC-113a (CF3CCl3, CFC-112 (CFCl2CFCl2 and HCFC-133a (CF3CH2Cl are three newly detected molecules in the atmosphere that are almost certainly emitted as a result of human activity. It is important to characterise the possible contribution of these gases to radiative forcing of climate change and also to provide information on the CO2-equivalence of their emissions. We report new laboratory measurements of absorption cross-sections of these three compounds at a resolution of 0.01 cm−1 for two temperatures 250 K and 295 K in the spectral range of 600–1730 cm−1. These spectra are then used to calculate the radiative efficiencies and global warming potentials (GWP. The radiative efficiencies are found to be between 0.15 and 0.3 W∙m−2∙ppbv−1. The GWP for a 100 year time horizon, relative to carbon dioxide, ranges from 340 for the relatively short-lived HCFC-133a to 3840 for the longer-lived CFC-112. At current (2012 concentrations, these gases make a trivial contribution to total radiative forcing; however, the concentrations of CFC-113a and HCFC-133a are continuing to increase. The 2012 CO2-equivalent emissions, using the GWP (100, are estimated to be about 4% of the current global CO2-equivalent emissions of HFC-134a.

  7. Some quantity aspects of the solar radiation in Mexicali, B.C., Mexico; Algunos aspectos cuantitativos de la radiacion solar en Mexicali, B.C., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Cueto; Rafael [Instituto de Ingenieria, U.A.B.C., Mexicali, Baja California (Mexico)

    2000-07-01

    Study of the global solar radiation is very useful for assesing the potential efficiency of systems designed for solar energy utilization. This paper explore some aspects of solar in Mexicali, B.C., Mexico, analysis of the monthly averages global solar radiation and general atmospheric transparency for the year 1998 are discussed. The statistical distribution of the clearness index is determined using histograms of frequencies. The percentage number of days with solar radiation values bellow a certain value is analyzed and discussed. The period of successive days having radiation less than 10 MJ/m{sup 2} dia-1 and 13 MJ/m{sup 2} dia{sup -}1 is examined and presented graphically. [Spanish] El estudio de la radiacion solar global es muy util para evaluar la eficiencia potencial de sistemas que en su diseno esten basados en la utilizacion de energia solar. En particular, en este articulo se exploran algunos aspectos cuantitativos de la radiacion solar en Mexicali, B.C., Mexico: se analizan los promedios mensuales de radiacion solar global y la transparencia atmosferica para el ano de 1998. Se determina la distribucion estadistica del indice de claridad usando histogramas de frecuencias. Se analizan y discuten el porcentaje de dias con valores de radiacion solar inferiores a cierto valor y se presentan graficamente el periodo de dias sucesivos que tienen valores de radiacion menores a 10 MJ/m{sup 2} dia{sup -}1 y 13MJ/m{sup 2} dia{sup -}1.

  8. Re-construction of global solar radiation time series from 1933 to 2013 at the Izaña Atmospheric Observatory

    Directory of Open Access Journals (Sweden)

    R. D. García

    2014-04-01

    Full Text Available This paper presents the re-construction of the 80 year time series of daily global shortwave downward radiation (SDR at the subtropical high-mountain Izaña Atmospheric Observatory (IZO, Spain. For this purpose, we combine SDR estimates from sunshine duration (SD data using the Ångström–Prescott method over the 1933/1991 period, and SDR observations directly performed by pyranometers between 1992 and 2013. Since SDR measurements have been used as a reference, a strict quality control has been applied, when it was not possible data have been re-calibrated by using the LibRadtran model. By comparing to high quality SDR measurements, the precision and consistency over time of SDR estimations from SD data have successfully been documented. We obtain a overall root mean square error (RMSE of 9.2% and an agreement between the variances of SDR estimations and SDR measurements within 92% (correlation coefficient of 0.96. Nonetheless, this agreement significantly increases when the SDR estimation is done considering different daily fractions of clear sky (FCS. In that case, RMSE is reduced by half, up to about 4.5%, when considering percentages of FCS > 40% (90% of days in the testing period. Furthermore, we prove that the SDR estimations can monitor the SDR anomalies in consistency with SDR measurements and, then, can be suitable for re-constructing solar radiation time series. The re-constructed IZO global SDR time series between 1933 and 2013 confirms discontinuities and periods of increases/decreases of solar radiation at Earth's surface observed at a global scale, such as the early brightening, dimming and brightening. This fact supports the consistency of the IZO SDR time series presented in this work, which may be a reference for solar radiation studies in the subtropical North Atlantic region.

  9. A study of uncertainties in the sulfate distribution and its radiative forcing associated with sulfur chemistry in a global aerosol model

    Directory of Open Access Journals (Sweden)

    D. Goto

    2011-11-01

    Full Text Available The direct radiative forcing by sulfate aerosols is still uncertain, mainly because the uncertainties are largely derived from differences in sulfate column burdens and its vertical distributions among global aerosol models. One possible reason for the large difference in the computed values is that the radiative forcing delicately depends on various simplifications of the sulfur processes made in the models. In this study, therefore, we investigated impacts of different parts of the sulfur chemistry module in a global aerosol model, SPRINTARS, on the sulfate distribution and its radiative forcing. Important studies were effects of simplified and more physical-based sulfur processes in terms of treatment of sulfur chemistry, oxidant chemistry, and dry deposition process of sulfur components. The results showed that the difference in the aqueous-phase sulfur chemistry among these treatments has the largest impact on the sulfate distribution. Introduction of all the improvements mentioned above brought the model values noticeably closer to in-situ measurements than those in the simplified methods used in the original SPRINTARS model. At the same time, these improvements also brought the computed sulfate column burdens and its vertical distributions into good agreement with other AEROCOM model values. The global annual mean radiative forcing due to the direct effect of anthropogenic sulfate aerosol was thus estimated to be −0.26 W m−2 (−0.30 W m−2 with a different SO2 inventory, whereas the original SPRINTARS model showed −0.18 W m−2 (−0.21 W m−2 with a different SO2 inventory. The magnitude of the difference between original and improved methods was approximately 50% of the uncertainty among estimates by the world's global aerosol models reported by the IPCC-AR4 assessment report. Findings in the present study, therefore, may suggest that the model differences in the

  10. Ultraviolet radiation climatology of the Earth`s surface and lower atmosphere. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Madronich, S. [National Center for Atmospheric Research, Boulder, CO (United States). Atmospheric Chemistry Div.; Stamnes, K. [Univ. of Alaska, Fairbanks, AK (United States). Dept. of Physics

    1999-03-01

    Ultraviolet (UV) radiation is the driving force of tropospheric chemistry and is furthermore detrimental to most living tissues. A three year modeling program was carried out to characterize the UV radiation in the lower atmosphere, with the objective of development a climatology of UV biologically active radiation, and of photo-dissociation reaction rates that are key to tropospheric chemistry. A comprehensive model, the Tropospheric Ultraviolet-Visible (TUV) model, was developed and made available to the scientific community. The model incorporates updated spectroscopic data, recent advances in radiative transfer theory, and allows flexible customization for the needs of different users. The TUV model has been used in conjunction with satellite-derived measurements of total atmospheric ozone and cloud amount, to develop a global climatology of UV radiation reaching the surface of the Earth. Initial validation studies are highly encouraging, showing that model predictions agree with direct measurements to ca. 5--10% at times when environmental conditions are well known, and to 10--30% for monthly averages when local environmental conditions can only be estimated remotely from satellite-based measurements. Additional validation studies are continuing.

  11. Reductions in soil surface albedo as a function of biochar application rate: implications for global radiative forcing

    NARCIS (Netherlands)

    Verheijen, F.G.A.; Jeffery, S.L.; Velde, te M.; Penizek, V.; Beland, M.; Bastos, A.C.; Keizer, J.J.

    2013-01-01

    Biochar can be defined as pyrolysed (charred) biomass produced for application to soils with the aim of mitigating global climate change while improving soil functions. Sustainable biochar application to soils has been estimated to reduce global greenhouse gas emissions by 71-130 Pg CO2-C-e over 100

  12. Reductions in soil surface albedo as a function of biochar application rate: implications for global radiative forcing

    NARCIS (Netherlands)

    Verheijen, F.G.A.; Jeffery, S.L.; Velde, te M.; Penizek, V.; Beland, M.; Bastos, A.C.; Keizer, J.J.

    2013-01-01

    Biochar can be defined as pyrolysed (charred) biomass produced for application to soils with the aim of mitigating global climate change while improving soil functions. Sustainable biochar application to soils has been estimated to reduce global greenhouse gas emissions by 71-130 Pg CO2-C-e over 100

  13. Hourly model to estimate solar global radiation for all months of the year for Botucatu, Sao Paulo State; Modelos horarios para estimativa da radiacao solar global para todos os meses do ano para Botucatu-SP

    Energy Technology Data Exchange (ETDEWEB)

    Laperuta Filho, Jayme; Lunardi, Dalva M. Cury [UNESP, Botucatu, SP (Brazil). Faculdade de Ciencias Agronomicas

    1997-12-31

    The objective of this work was establish and daily models for estimate of solar global radiation for the months of the year, in Botucatu-SP 22 deg C 52`S,48 deg C 26`W Grw). The obtention of these models showed be viable high degree of reliability considering that they are specific for hours and months that originated them. The coefficients a and b presented monthly and hourly variations, taking into account that b showed higher relative variability than a. In all months studied, the linear adjustment was not appropriate before 7 a.m and after 5 p.m. (author) 7 refs., 5 tabs.

  14. 球形磁单极荷电黑洞的Hawking辐射%The Hawking Radiation of the Charged Black Hole with a Global Monopole

    Institute of Scientific and Technical Information of China (English)

    刘晶晶; 陈德友

    2008-01-01

    Applying Hamliton-Jacobi method, the tunneling characteristic of the charged black hole with a global monopole is investigated by taking the self-gravitational interaction as well as the energy conservation and charge conservation into account. The radiation spectrum deviates from the purely thermal one and the tunneling probability is related to the change of Bekenstein-Hawking entropy. The result satisfies an underlying unitary theory and gives a correction to the Hawking radiation.%利用Hamliton-Jacobi方法,考虑自引力作用及能量和电荷守恒研究了球形磁单极荷电黑洞的隧穿辐射特性,得到的隧穿辐射谱不再是纯热谱,其隧穿几率与Hawking熵有关,所得到结果满足幺正性原理且对Hawking辐射进行了修正.

  15. Modeling radiation belt radial diffusion in ULF wave fields: 1. Quantifying ULF wave power at geosynchronous orbit in observations and in global MHD model

    Science.gov (United States)

    Huang, Chia-Lin; Spence, Harlan E.; Singer, Howard J.; Hughes, W. Jeffrey

    2010-06-01

    To provide critical ULF wave field information for radial diffusion studies in the radiation belts, we quantify ULF wave power (f = 0.5-8.3 mHz) in GOES observations and magnetic field predictions from a global magnetospheric model. A statistical study of 9 years of GOES data reveals the wave local time distribution and power at geosynchronous orbit in field-aligned coordinates as functions of wave frequency, solar wind conditions (Vx, ΔPd and IMF Bz) and geomagnetic activity levels (Kp, Dst and AE). ULF wave power grows monotonically with increasing solar wind Vx, dynamic pressure variations ΔPd and geomagnetic indices in a highly correlated way. During intervals of northward and southward IMF Bz, wave activity concentrates on the dayside and nightside sectors, respectively, due to different wave generation mechanisms in primarily open and closed magnetospheric configurations. Since global magnetospheric models have recently been used to trace particles in radiation belt studies, it is important to quantify the wave predictions of these models at frequencies relevant to electron dynamics (mHz range). Using 27 days of real interplanetary conditions as model inputs, we examine the ULF wave predictions modeled by the Lyon-Fedder-Mobarry magnetohydrodynamic code. The LFM code does well at reproducing, in a statistical sense, the ULF waves observed by GOES. This suggests that the LFM code is capable of modeling variability in the magnetosphere on ULF time scales during typical conditions. The code provides a long-missing wave field model needed to quantify the interaction of radiation belt electrons with realistic, global ULF waves throughout the inner magnetosphere.

  16. Development of a site-independent mathematical model for the estimation of global solar radiation on earth’s surface around the globe

    Directory of Open Access Journals (Sweden)

    Iranna Korachagaon, V.N. Bapat

    2012-01-01

    Full Text Available Measured air temperature, relative humidity, wind and moisture measurements for 210 sites around the earth were used for the model development. The models were formulated using multi-parameter input regression type empirical relations. The estimation of Global Solar Radiation (GSR were made using various combinations of data sets, with use of 1 parameter to 11 parameters. After validation with 665 data sites on these models, finally two candidate models have been proposed. These models are capable of covering 50% of the land area on earth surface between latitude ± 30º, enabling estimation accuracy to 93% of sites, with RMSE limiting to 15%.

  17. Estimation of spectral solar radiation based on global insolation and characteristics of spectral solar radiation on a tilt surface; Zenten nissharyo ni motozuku zenten nissha supekutoru no suitei to keishamen bunko tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Baba, H.; Kanayama, K.; Endo, N.; Koromohara, K.; Takayama, H. [Kitami Institute of Technology, Hokkaido (Japan)

    1996-10-27

    Use of global insolation for estimating the corresponding spectral distribution is proposed. Measurements of global insolation spectrum throughout a year were compiled for clear days and cloudy days, ranked by 100W/m{sup 2}, for the clarification of spectral distribution. Global insolation quantity for a clear day was subject mainly to sun elevation. The global insolation spectral distribution with the sun elevation not lower than 15{degree} was similar to Bird`s model. Under the cloudy sky, energy density was lower in the region of wavelengths longer than the peak wavelength of 0.46{mu}m, and the distribution curve was sharper than that under the clear sky. Values given by Bird`s model were larger than measured values in the wavelength range of 0.6-1.8{mu}m, which was attributed to absorption by vapor. From the standard spectral distribution charts for the clear sky and cloudy sky, and from the dimensionless spectral distributions obtained by dividing them by the peak values, spectral distributions could be estimated of insolation quantities for the clear sky, cloudy sky, etc. As for the characteristics of spectral solar radiation on a tilt surface obtained from Bird`s model, they agreed with actually measured values at an angle of inclination of 60{degree} or smaller. 6 refs., 10 figs., 1 tab.

  18. Relationship between Net Radiation and Broadband Solar Radiation in the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    HU Bo; WANG Yuesi; LIU Guangren

    2012-01-01

    The characteristics of net radiation (Rn) (0.3-10 μm) in Lhasa and Haibei in the Tibetan Plateau were analyzed based on long-term in-situ measurements of surface radiation data.The monthly average of daily Rn reached a minimum during the winter period followed by an increase until May and then a decline until January.This variation is consistent with solar activity.The annual mean daily total Rn values were 0.92MJ m-2 d-1 and 0.66 MJ m-2 d-1 in Lhasa and Haibei,respectively.A relationship between Rn and broadband solar radiation (Rs) was demonstrated by a good linear correlation at the two sites.Rn can be an accurate estimate from Rs.The estimated Rn values were similar to the observed values,and the relative deviations between the estimates and measurements of Rn were 2.8% and 3.8% in Lhasa and Haibei,respectively.The application of the Rn estimating model to other locations showed that it could provide acceptable estimated Rn values from the Rs data.Furthermore,we analyzed the influence of clouds on Rn by different clear index (Ks),defined as the ratio of Rs to the extraterrestrial solar irradiance on a horizontal surface.The results indicate that more accurate results are associated with increased cloudy conditions.The influence of the albedo was also considered,but its inclusion in the model resulted in only a slight improvement.Because surface albedo is not usually measured,an expression based solely on global solar radiation could be of more extensive use.

  19. Construction of a Matched Global Cloud and Radiance Product from LEO/GEO and EPIC Observations to Estimate Daytime Earth Radiation Budget from DSCOVR

    Science.gov (United States)

    Duda, David P.; Khlopenkov, Konstantin V.; Thiemann, Mandana; Palikonda, Rabindra; Sun-Mack, Sunny; Minnis, Patrick; Su, Wenying

    2016-01-01

    With the launch of the Deep Space Climate Observatory (DSCOVR), new estimates of the daytime Earth radiation budget can be computed from a combination of measurements from the two Earth-observing sensors onboard the spacecraft, the Earth Polychromatic Imaging Camera (EPIC) and the National Institute of Standards and Technology Advanced Radiometer (NISTAR). Although these instruments can provide accurate top-of-atmosphere (TOA) radiance measurements, they lack sufficient resolution to provide details on small-scale surface and cloud properties. Previous studies have shown that these properties have a strong influence on the anisotropy of the radiation at the TOA, and ignoring such effects can result in large TOA-flux errors. To overcome these effects, high-resolution scene identification is needed for accurate Earth radiation budget estimation. Selected radiance and cloud property data measured and derived from several low earth orbit (LEO, including NASA Terra and Aqua MODIS, NOAA AVHRR) and geosynchronous (GEO, including GOES (east and west), METEOSAT, INSAT-3D, MTSAT-2, and HIMAWARI-8) satellite imagers were collected to create hourly 5-km resolution global composites of data necessary to compute angular distribution models (ADM) for reflected shortwave (SW) and longwave (LW) radiation. The satellite data provide an independent source of radiance measurements and scene identification information necessary to construct ADMs that are used to determine the daytime Earth radiation budget. To optimize spatial matching between EPIC measurements and the high-resolution composite cloud properties, LEO/GEO retrievals within the EPIC fields of view (FOV) are convolved to the EPIC point spread function (PSF) in a similar manner to the Clouds and the Earth's Radiant Energy System (CERES) Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product. Examples of the merged LEO/GEO/EPIC product will be presented, describing the chosen radiance and cloud properties and

  20. High-resolution global grids of revised Priestley–Taylor and Hargreaves–Samani coefficients for assessing ASCE-standardized reference crop evapotranspiration and solar radiation

    Directory of Open Access Journals (Sweden)

    V. G. Aschonitis

    2017-08-01

    Full Text Available The objective of the study is to provide global grids (0.5° of revised annual coefficients for the Priestley–Taylor (P-T and Hargreaves–Samani (H-S evapotranspiration methods after calibration based on the ASCE (American Society of Civil Engineers-standardized Penman–Monteith method (the ASCE method includes two reference crops: short-clipped grass and tall alfalfa. The analysis also includes the development of a global grid of revised annual coefficients for solar radiation (Rs estimations using the respective Rs formula of H-S. The analysis was based on global gridded climatic data of the period 1950–2000. The method for deriving annual coefficients of the P-T and H-S methods was based on partial weighted averages (PWAs of their mean monthly values. This method estimates the annual values considering the amplitude of the parameter under investigation (ETo and Rs giving more weight to the monthly coefficients of the months with higher ETo values (or Rs values for the case of the H-S radiation formula. The method also eliminates the effect of unreasonably high or low monthly coefficients that may occur during periods where ETo and Rs fall below a specific threshold. The new coefficients were validated based on data from 140 stations located in various climatic zones of the USA and Australia with expanded observations up to 2016. The validation procedure for ETo estimations of the short reference crop showed that the P-T and H-S methods with the new revised coefficients outperformed the standard methods reducing the estimated root mean square error (RMSE in ETo values by 40 and 25 %, respectively. The estimations of Rs using the H-S formula with revised coefficients reduced the RMSE by 28 % in comparison to the standard H-S formula. Finally, a raster database was built consisting of (a global maps for the mean monthly ETo values estimated by ASCE-standardized method for both reference crops, (b global maps for the revised annual

  1. Comparison of global irradiance measurements of the official Spanish radiometric network for 2006 with satellite estimated data

    Directory of Open Access Journals (Sweden)

    J. M. Sancho

    2011-01-01

    Full Text Available The monthly average values of daily global irradiance measured in broadband at 40 stations of the National Radiometric Network of the Spanish Meteorological Agency have been compared with the monthly values of SIS (Surface Incoming Shortwave radiation of the Climate Monitoring-Satellite Application Facility for 2006. It is calculated by the data from the instrument Spinning Enhanced Visible and Infrared Imager of the Meteosat Second Generation satellite and of the Advanced Very High Resolution Radiometer of the NOAA polar satellites. The results show a great similarity between the data from both sources of information, and the discrepancies found are around 5%. The aim of such a comparison is to evaluate the suitability of the use of the SIS data for the elaboration of an atlas of solar irradiance available in Spain.

  2. Studying the Physical Basis of Global Warming: Thermal Effects of the Interaction between Radiation and Matter and Greenhouse Effect

    Science.gov (United States)

    Besson, Ugo; De Ambrosis, Anna; Mascheretti, Paolo

    2010-01-01

    We present a teaching module dealing with the thermal effects of interaction between radiation and matter, the infrared emission of bodies and the greenhouse effect devoted to university level and teacher education. The module stresses the dependence of the optical properties of materials (transparency, absorptivity and emissivity) on radiation…

  3. Studying the Physical Basis of Global Warming: Thermal Effects of the Interaction between Radiation and Matter and Greenhouse Effect

    Science.gov (United States)

    Besson, Ugo; De Ambrosis, Anna; Mascheretti, Paolo

    2010-01-01

    We present a teaching module dealing with the thermal effects of interaction between radiation and matter, the infrared emission of bodies and the greenhouse effect devoted to university level and teacher education. The module stresses the dependence of the optical properties of materials (transparency, absorptivity and emissivity) on radiation…

  4. Variability in UVB radiation in Beijing, China.

    Science.gov (United States)

    Bo, Hu; Xinghua, Zhang; Yuesi, Wang

    2013-01-01

    The variation characteristics of Ultraviolet-B (UVB; 280-315 nm) radiation over Beijing were explored using measured data that were collected in Beijing from November 2010 to October 2011. Seasonal variations in UVB radiation and influence of ozone and clearness index on the ratio of UVB to broadband solar radiation (G) were investigated. The annual value of UVB radiation in Beijing is 6.37 MJ m(-2), and monthly average value ranges from 4.96 to 28.37 kJ m(-2) d(-1). The maximum daily total UVB radiation ranges from 6.55 kJ m(-2) d(-1) in November to 54.22 kJ m(-2) d(-1) in July. The monthly minimum of daily total UVB radiation varies from 0.5 kJ m(-2) d(-1) in February to 11.52 kJ m(-2) d(-1) in July. The monthly average of the ratio of UVB radiation to G ranges from 0.007 to 0.017%, with an annual average value of 0.012%. The variation in slant ozone column causes annual cycle of the ratio UVB radiation to G, with maximum value in summer. In addition, clouds have a greater effect on G than UVB radiation. Thus, the ratio increases by more than 17% when the atmospheric conditions change from clear to cloudy.

  5. Atmospheric lifetimes, infrared absorption spectra, radiative forcings and global warming potentials of NF3 and CF3CF2Cl (CFC-115)

    Science.gov (United States)

    Totterdill, Anna; Kovács, Tamás; Feng, Wuhu; Dhomse, Sandip; Smith, Christopher J.; Gómez-Martín, Juan Carlos; Chipperfield, Martyn P.; Forster, Piers M.; Plane, John M. C.

    2016-09-01

    Fluorinated compounds such as NF3 and C2F5Cl (CFC-115) are characterised by very large global warming potentials (GWPs), which result from extremely long atmospheric lifetimes and strong infrared absorptions in the atmospheric window. In this study we have experimentally determined the infrared absorption cross sections of NF3 and CFC-115, calculated the radiative forcing and efficiency using two radiative transfer models and identified the effect of clouds and stratospheric adjustment. The infrared cross sections are within 10 % of previous measurements for CFC-115 but are found to be somewhat larger than previous estimates for NF3, leading to a radiative efficiency for NF3 that is 25 % larger than that quoted in the Intergovernmental Panel on Climate Change Fifth Assessment Report. A whole atmosphere chemistry-climate model was used to determine the atmospheric lifetimes of NF3 and CFC-115 to be (509 ± 21) years and (492 ± 22) years, respectively. The GWPs for NF3 are estimated to be 15 600, 19 700 and 19 700 over 20, 100 and 500 years, respectively. Similarly, the GWPs for CFC-115 are 6030, 7570 and 7480 over 20, 100 and 500 years, respectively.

  6. Relevant Analysis of Grassland Temperature and Ground Net Radiation in Guilin

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The aim was to study the relevance of grassland temperature and ground net radiation in Guilin.[Method] By dint of ground observation data and net radiation of national benchmark climate station in Guilin from 2007 to 2009,the changes of grassland temperature and ground net radiation were expounded and their relations were pointed out.[Result] The annual changes trends of grassland temperature and ground net radiation in Guilin were basically the same.Monthly average maximum value all appeared i...

  7. Hawking Radiation of Charged and Magnetized Particles from the Global Monopole Black Hole with Quantum Gravity Effects

    CERN Document Server

    Jusufi, Kimet

    2016-01-01

    In this paper we study the quantum tunneling of charged and magnetized particles (magnetic monopoles) from the global monopole black hole by incorporating the quantum gravity effects. Starting from the modified Maxwell's equations and Generalized Uncertainty Relation (GUP), we recover the GUP corrected temperate for the global monopole black hole by solving the modified Dirac equation via Hamilton-Jacobi method. Furthermore, we also include the quantum corrections beyond the semiclassical approximation, in particular, first we find the logarithmic corrections of GUP corrected entropy and finally we calculate the GUP corrected specific heat capacity.

  8. Developing a global mixed-canopy, height-variable vegetation structure dataset for estimating global vegetation albedo by a clumped canopy radiative transfer scheme in the NASA Ent Terrestrial Biosphere Model and GISS GCM

    Science.gov (United States)

    Montes, Carlo; Kiang, Nancy Y.; Ni-Meister, Wenge; Yang, Wenze; Schaaf, Crystal; Aleinov, Igor; Jonas, Jeffrey A.; Zhao, Feng; Yao, Tian; Wang, Zhuosen; Sun, Qingsong; Carrer, Dominique

    2016-04-01

    Processes determining biosphere-atmosphere coupling are strongly influenced by vegetation structure. Thus, ecosystem carbon sequestration and evapotranspiration affecting global carbon and water balances will depend upon the spatial extent of vegetation, its vertical structure, and its physiological variability. To represent this globally, Dynamic Global Vegetation Models (DGVMs) coupled to General Circulation Models (GCMs) make use of satellite and/or model-based vegetation classifications often composed by homogeneous communities. This work aims at developing a new Global Vegetation Structure Dataset (GVSD) by incorporating varying vegetation heights for mixed plant communities to be used as boundary conditions to the Analytical Clumped Two-Stream (ACTS) canopy radiative transfer scheme (Ni-Meister et al., 2010) incorporated into the NASA Ent Terrestrial Biosphere Model (TBM), the DGVM coupled to the NASA Goddard Institute for Space Studies (GISS) GCM. Information sources about land surface and vegetation characteristics obtained from a number of earth observation platforms and algorithms include the Moderate Resolution Imaging Spectroradiometer (MODIS) land cover and plant functional types (PFTs) (Friedl et al., 2010), soil albedo derived from MODIS (Carrer et al., 2014), along with vegetation height from the Geoscience Laser Altimeter System (GLAS) on board ICESat (Ice, Cloud, and land Elevation Satellite) (Simard et al., 2011; Tang et al., 2014). Three widely used Leaf Area Index (LAI) products are compared as input to the GVSD and ACTS forcing in terms of vegetation albedo: Global Data Sets of Vegetation (LAI)3g (Zhu et al. 2013), Beijing Normal University LAI (Yuan et al., 2011), and MODIS MOD15A2H product (Yang et al., 2006). Further PFT partitioning is performed according to a climate classification utilizing the Climate Research Unit (CRU; Harris et al., 2013) and the NOAA Global Precipitation Climatology Centre (GPCC; Scheider et al., 2014) data. Final

  9. Atmospheric, radiative, and hydrologic effects of future land use and land cover changes: A global and multimodel climate picture

    Science.gov (United States)

    Quesada, Benjamin; Arneth, Almut; de Noblet-Ducoudré, Nathalie

    2017-05-01

    Land use and land cover changes (LULCC) modulate land surface energy, heat, moisture, and momentum fluxes. Using simulations performed with and without LULCC for five earth system models, averaged over the 2071-2100 period, we quantify the biophysical effects in response to a future realistic LULCC scenario (Representative Concentration Pathway RCP8.5) on 15 climate variables (i.e., atmospheric, radiative, wind, hydrologic variables, and heat fluxes). We find that climate models are able to simulate some robust and strong climate perturbations in response to LULCC. In tropical regions with substantial LULCC, significantly higher skin temperatures, less precipitation and soil moisture, less evaporation and clouds, more incoming radiation and stronger winds, more anticyclonic conditions and subsidence, are simulated in response to future LULCC. In midlatitude and high latitude, LULCC result in autumn cooling and higher tropospheric pressures, while East Asia is drier, warmer, with higher sensible heat flux and lower evaporation. The tropical wind strengthening and weakening of the hydrological cycle are comparable in magnitude to their future regional changes induced by greenhouse gases under RCP8.5, which make LULCC an indispensable forcing to take into account in future climatic assessments. Finally, our study reveals significant indirect atmospheric processes triggered by LULCC, implying substantial changes in incoming radiation, which dominate climatic responses over the direct effects, particularly in boreal regions.

  10. Assessment of BSRN radiation records for the computation of monthly means

    Energy Technology Data Exchange (ETDEWEB)

    Roesch, Andreas; Wild, Martin F.; Ohmura, Atsumu; Dutton, Ellsworth G.; Long, Charles N.; Zhang, Taiping

    2011-02-23

    The accuracy of the Baseline Surface Radiation Network (BSRN) radiation monthly averages are assessed by investigating data gap frequency due to missing or discarded high time resolution data. The monthly statistics, especially means are considered to be important and useful values for climate research, model performance evaluations and for assessing the quality of satellite computations. The study investigates the spread in different algorithms that have been applied for the computation of monthly means from minute values. We found that a substantial fraction of the radiation fluxes observed at BSRN sites is either missing or flagged as questionable. The percentage of missing data is 4.4%, 13.0%, and 6.5% for global radiation, direct shortwave radiation, and downwelling longwave radiation, respectively. Most flagged data in the shortwave are due to nighttime instrumental noise and can reasonably be set to zero after correcting for thermal offsets in the daytime data. The paper reveals that the computation of monthly means from 1-minute observations distinctly depends on the selected method. The intra-method difference generally increases with an increasing fraction of missing data. The study demonstrates that the handling of flagged data clearly impacts on monthly mean estimates obtained with different methods. We showed that the spread of monthly shortwave fluxes are generally clearly higher than for downwelling longwave radiation. Overall, BSRN observation provide sufficient accuracy and completeness for reliable estimates of monthly mean values. However, we should aim at further increasing the data quality by reducing the data gap frequency and the number of outliers. The authors suggest using a standardized method for the computation of monthly means in order to avoid a mismatch of published monthly mean radiation fluxes from BSRN.

  11. Detection of Nonlinearity of the Solar Radiation Time Series%太阳辐射时间序列的非线性检验

    Institute of Scientific and Technical Information of China (English)

    李余琪; 彭江北; 甘敏

    2012-01-01

    It is important and beneficial to test the nonlinearity of the solar radiation time series for their analysis,modeling and prediction. This paper tests the nonlinearity of the solar radiation time series based on the surrogate data method,and the third-order moment of the time series is used as the test statistic. The daily global solar radiation data from Dillon,Montana and Green River,Wyoming and the monthly average daily global solar radiation data are cosidered. The statistical results of the numerical analysis show that the daily global solar radiation time series exists nonliearity,whereas the monthly average daily global solar radiation time seires does not. So,it is necessary to test the nonliearity before modedling and predicting the solar radation.%检验太阳辐射时间序列是否有非线性特征,对于分析、建模和预测太阳辐射量是重要、有益的.提出用基于替代数据的检验方法来检验太阳辐射时间序列是否存在非线性特征,并将数据序列的三阶矩作为检验统计量.选取了美国Montana州Dillon地区和Wyoming州Green River地区每日总辐射量、Utah州Moab地区的每月日平均总辐射量时间序列作为检验对象.数值分析的统计结果表明所研究的日总辐射时间序列存在非线性,而每月日平均总辐射时间序列未检测出非线性.因而,对太阳辐射时间序列建模和预测之前,检验其是否有非线性特征是必要的.

  12. Prognostic land surface albedo from a dynamic global vegetation model clumped canopy radiative transfer scheme and satellite-derived geographic forest heights

    Science.gov (United States)

    Kiang, N. Y.; Yang, W.; Ni-Meister, W.; Aleinov, I. D.; Jonas, J.

    2014-12-01

    Vegetation cover was introduced into general circulations models (GCMs) in the 1980's to account for the effect of land surface albedo and water vapor conductance on the Earth's climate. Schemes assigning canopy albedoes by broad biome type have been superceded in 1990's by canopy radiative transfer schemes for homogeneous canopies obeying Beer's Law extinction as a function of leaf area index (LAI). Leaf albedo and often canopy height are prescribed by plant functional type (PFT). It is recognized that this approach does not effectively describe geographic variation in the radiative transfer of vegetated cover, particularly for mixed and sparse canopies. GCM-coupled dynamic global vegetation models (DGVMs) have retained these simple canopy representations, with little further evaluation of their albedos. With the emergence lidar-derived canopy vertical structure data, DGVM modelers are now revisiting albedo simulation. We present preliminary prognostic global land surface albedo produced by the Ent Terrestrial Biosphere Model (TBM), a DGVM coupled to the NASA Goddard Institute for Space Studies (GISS) GCM. The Ent TBM is a next generation DGVM designed to incorporate variation in canopy heights, and mixed and sparse canopies. For such dynamically varying canopy structure, it uses the Analytical Clumped Two-Stream (ACTS) canopy radiative transfer model, which is derived from gap probability theory for canopies of tree cohorts with ellipsoidal crowns, and accounts for soil, snow, and bare stems. We have developed a first-order global vegetation structure data set (GVSD), which gives a year of satellite-derived geographic variation in canopy height, maximum canopy leaf area, and seasonal LAI. Combined with Ent allometric relations, this data set provides population density and foliage clumping within crowns. We compare the Ent prognostic albedoes to those of the previous GISS GCM scheme, and to satellite estimates. The impact of albedo differences on surface

  13. Compatibility of different measurement techniques of global solar radiation and application for long-term observations at Izaña Observatory

    Science.gov (United States)

    Delia García, Rosa; Cuevas, Emilio; García, Omaira Elena; Ramos, Ramón; Romero-Campos, Pedro Miguel; de Ory, Fernado; Cachorro, Victoria Eugenia; de Frutos, Angel

    2017-03-01

    A 1-year inter-comparison of classical and modern radiation and sunshine duration (SD) instruments has been performed at Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain) starting on 17 July 2014. We compare daily global solar radiation (GSRH) records measured with a Kipp & Zonen CM-21 pyranometer, taken in the framework of the Baseline Surface Radiation Network, with those measured with a multifilter rotating shadowband radiometer (MFRSR), a bimetallic pyranometer (PYR) and GSRH estimated from sunshine duration performed by a Campbell-Stokes sunshine recorder (CS) and a Kipp & Zonen sunshine duration sensor (CSD). Given that the BSRN GSRH records passed strict quality controls (based on principles of physical limits and comparison with the LibRadtran model), they have been used as reference in the inter-comparison study. We obtain an overall root mean square error (RMSE) of ˜ 0.9 MJm-2 (4 %) for PYR and MFRSR GSRH, 1.9 (7 %) and 1.2 MJm-2 (5 %) for CS and CSD GSRH, respectively. Factors such as temperature, relative humidity (RH) and the solar zenith angle (SZA) have been shown to moderately affect the GSRH observations. As an application of the methodology developed in this work, we have re-evaluated the GSRH data time series obtained at IZO with two PYRs between 1977 and 1991. Their high consistency and temporal stability have been proved by comparing with GSRH estimates obtained from SD observations. These results demonstrate that (1) the continuous-basis inter-comparison of different GSRH techniques offers important diagnostics for identifying inconsistencies between GSRH data records, and (2) the GSRH measurements performed with classical and more simple instruments are consistent with more modern techniques and, thus, valid to recover GSRH data time series and complete worldwide distributed GSRH data. The inter-comparison and quality assessment of these different techniques have allowed us to obtain a complete and consistent

  14. On the uses of a new linear scheme for stratospheric methane in global models: water source, transport tracer and radiative forcing

    Directory of Open Access Journals (Sweden)

    B. M. Monge-Sanz

    2013-09-01

    Full Text Available This study evaluates effects and applications of a new linear parameterisation for stratospheric methane and water vapour. The new scheme (CoMeCAT is derived from a 3-D full-chemistry-transport model (CTM. It is suitable for any global model, and is shown here to produce realistic profiles in the TOMCAT/SLIMCAT 3-D CTM and the ECMWF (European Centre for Medium-Range Weather Forecasts general circulation model (GCM. Results from the new scheme are in good agreement with the full-chemistry CTM CH4 field and with observations from the Halogen Occultation Experiment (HALOE. The scheme is also used to derive stratospheric water increments, which in the CTM produce vertical and latitudinal H2O variations in fair agreement with satellite observations. Stratospheric H2O distributions in the ECMWF GCM show realistic overall features, although concentrations are smaller than in the CTM run (up to 0.5 ppmv smaller above 10 hPa. The potential of the new CoMeCAT tracer for evaluating stratospheric transport is exploited to assess the impacts of nudging the free-running GCM to ERA-40 and ERA-Interim reanalyses. The nudged GCM shows similar transport patterns to the offline CTM forced by the corresponding reanalysis data. The new scheme also impacts radiation and temperature in the model. Compared to the default CH4 climatology and H2O used by the ECMWF radiation scheme, the main effect on ECMWF temperatures when considering both CH4 and H2O from CoMeCAT is a decrease of up to 1.0 K over the tropical mid/low stratosphere. The effect of using the CoMeCAT scheme for radiative forcing (RF calculations is investigated using the offline Edwards–Slingo radiative transfer model. Compared to the default model option of a tropospheric global 3-D CH4 value, the CoMeCAT distribution produces an overall change in the annual mean net RF of up to −30 mW m−2.

  15. Projected changes in surface solar radiation in CMIP5 global climate models and in EURO-CORDEX regional climate models for Europe

    Science.gov (United States)

    Bartók, Blanka; Wild, Martin; Folini, Doris; Lüthi, Daniel; Kotlarski, Sven; Schär, Christoph; Vautard, Robert; Jerez, Sonia; Imecs, Zoltán

    2016-12-01

    The objective of the present work is to compare the projections of surface solar radiation (SSR) simulated by four regional climate models (CCLM, RCA4, WRF, ALADIN) with the respective fields of their ten driving CMIP5 global climate models. First the annual and seasonal SSR changes are examined in the regional and in the global climate models based on the RCP8.5 emission scenarios. The results show significant discrepancies between the projected SSR, the multi-model mean of RCMs indicates a decrease in SSR of -0.60 W/m2 per decade over Europe, while the multi-model mean of the associated GCMs used to drive the RCMs gives an increase in SSR of +0.39 W/m2 per decade for the period of 2006-2100 over Europe. At seasonal scale the largest differences appear in spring and summer. The different signs of SSR projected changes can be interpreted as the consequence of the different behavior of cloud cover in global and regional climate models. Cloudiness shows a significant decline in GCMs with -0.24% per decade which explains the extra income in SSR, while in case of the regional models no significant changes in cloudiness can be detected. The reduction of SSR in RCMs can be attributed to increasing atmospheric absorption in line with the increase of water vapor content. Both global and regional models overestimate SSR in absolute terms as compared to surface observations, in line with an underestimation of cloud cover. Regional models further have difficulties to adequately reproduce the observed trends in SSR over the past decades.

  16. Global Gene Expression Alterations as a Crucial Constituent of Human Cell Response to Low Doses of Ionizing Radiation Exposure

    Science.gov (United States)

    Sokolov, Mykyta; Neumann, Ronald

    2015-01-01

    Exposure to ionizing radiation (IR) is inevitable to humans in real-life scenarios; the hazards of IR primarily stem from its mutagenic, carcinogenic, and cell killing ability. For many decades, extensive research has been conducted on the human cell responses to IR delivered at a low dose/low dose (LD) rate. These studies have shown that the molecular-, cellular-, and tissue-level responses are different after low doses of IR (LDIR) compared to those observed after a short-term high-dose IR exposure (HDIR). With the advent of high-throughput technologies in the late 1990s, such as DNA microarrays, changes in gene expression have also been found to be ubiquitous after LDIR. Very limited subset of genes has been shown to be consistently up-regulated by LDIR, including CDKN1A. Further research on the biological effects and mechanisms induced by IR in human cells demonstrated that the molecular and cellular processes, including transcriptional alterations, activated by LDIR are often related to protective responses and, sometimes, hormesis. Following LDIR, some distinct responses were observed, these included bystander effects, and adaptive responses. Changes in gene expression, not only at the level of mRNA, but also miRNA, have been found to crucially underlie these effects having implications for radiation protection purposes. PMID:26729107

  17. Global Gene Expression Alterations as a Crucial Constituent of Human Cell Response to Low Doses of Ionizing Radiation Exposure

    Directory of Open Access Journals (Sweden)

    Mykyta Sokolov

    2015-12-01

    Full Text Available Exposure to ionizing radiation (IR is inevitable to humans in real-life scenarios; the hazards of IR primarily stem from its mutagenic, carcinogenic, and cell killing ability. For many decades, extensive research has been conducted on the human cell responses to IR delivered at a low dose/low dose (LD rate. These studies have shown that the molecular-, cellular-, and tissue-level responses are different after low doses of IR (LDIR compared to those observed after a short-term high-dose IR exposure (HDIR. With the advent of high-throughput technologies in the late 1990s, such as DNA microarrays, changes in gene expression have also been found to be ubiquitous after LDIR. Very limited subset of genes has been shown to be consistently up-regulated by LDIR, including CDKN1A. Further research on the biological effects and mechanisms induced by IR in human cells demonstrated that the molecular and cellular processes, including transcriptional alterations, activated by LDIR are often related to protective responses and, sometimes, hormesis. Following LDIR, some distinct responses were observed, these included bystander effects, and adaptive responses. Changes in gene expression, not only at the level of mRNA, but also miRNA, have been found to crucially underlie these effects having implications for radiation protection purposes.

  18. Evaluation of cloud fraction and its radiative effect simulated by IPCC AR4 global models against ARM surface observations

    Directory of Open Access Journals (Sweden)

    Y. Qian

    2012-02-01

    Full Text Available Cloud Fraction (CF is the dominant modulator of radiative fluxes. In this study, we evaluate CF simulated in the IPCC AR4 GCMs against ARM long-term ground-based measurements, with a focus on the vertical structure, total amount of cloud and its effect on cloud shortwave transmissivity. Comparisons are performed for three climate regimes as represented by the Department of Energy Atmospheric Radiation Measurement (ARM sites: Southern Great Plains (SGP, Manus, Papua New Guinea and North Slope of Alaska (NSA. Our intercomparisons of three independent measurements of CF or sky-cover reveal that the relative differences are usually less than 10% (5% for multi-year monthly (annual mean values, while daily differences are quite significant. The total sky imager (TSI produces smaller total cloud fraction (TCF compared to a radar/lidar dataset for highly cloudy days (CF > 0.8, but produces a larger TCF value than the radar/lidar for less cloudy conditions (CF < 0.3. The compensating errors in lower and higher CF days result in small biases of TCF between the vertically pointing radar/lidar dataset and the hemispheric TSI measurements as multi-year data is averaged. The unique radar/lidar CF measurements enable us to evaluate seasonal variation of cloud vertical structures in the GCMs.

    Both inter-model deviation and model bias against observation are investigated in this study. Another unique aspect of this study is that we use simultaneous measurements of CF and surface radiative fluxes to diagnose potential discrepancies among the GCMs in representing other cloud optical properties than TCF. The results show that the model-observation and inter-model deviations have similar magnitudes for the TCF and the normalized cloud effect, and these deviations are larger than those in surface downward solar radiation and cloud transmissivity. This implies that other dimensions of cloud in addition to cloud amount, such as cloud optical thickness and

  19. Radiation balance at the surface in the city of São Paulo, Brazil: diurnal and seasonal variations

    NARCIS (Netherlands)

    Ferreira, M.J.; Oliveira, de A.P.; Soares, J.; Codato, G.; Wilde Barbaro, E.; Escobedo, J.F.

    2012-01-01

    The main goal of this work is to describe the diurnal and seasonal variations of the radiation balance components at the surface in the city of São Paulo based on observations carried out during 2004. Monthly average hourly values indicate that the amplitudes of the diurnal cycles of net radiation (

  20. Global emission estimates and radiative impact of C4F10, C5F12, C6F14, C7F16 and C8F18

    Science.gov (United States)

    Ivy, D. J.; Rigby, M.; Baasandorj, M.; Burkholder, J. B.; Prinn, R. G.

    2012-08-01

    estimated in this study. In addition, we present measured infrared absorption spectra for C7F16 and C8F18, and estimate their radiative efficiencies and global warming potentials (GWPs). We find that C8F18's radiative efficiency is similar to trifluoromethyl sulfur pentafluoride's (SF5F3) at 0.57 W m-2 ppb-1, which is the highest radiative efficiency of any measured atmospheric species. Using the 100-yr time horizon GWPs, the total radiative impact of the high molecular weight perfluorocarbons emissions are also estimated; we find the high molecular weight PFCs peak contribution was in 1997 at 24 000 Gg of carbon dioxide (CO2) equivalents and has decreased by a factor of three to 7300 Gg of CO2 equivalents in 2010. This 2010 cumulative emission rate for the high molecular weight PFCs is comparable to: 0.02% of the total CO2 emissions, 0.81% of the total hydrofluorocarbon emissions, or 1.07% of the total chlorofluorocarbon emissions projected for 2010 (Velders et al., 2009). In terms of the total PFC emission budget, including the lower molecular weight PFCs, the high molecular weight PFCs peak contribution was also in 1997 at 15.4% and was 6% of the total PFC emissions in CO2 equivalents in 2009.

  1. Experimental investigations of the distribution of pulsed-plasma-generator radiation at its various spatial orientation and global anisotropy of space

    Energy Technology Data Exchange (ETDEWEB)

    Baurov, Yu.A.; Timofeev, I.B.; Chernikov, V.A.; Chalkin, S.F.; Konradov, A.A

    2003-05-26

    Results of experimental investigation of plasma luminous emittance (integrated with respect to time and quartz transmission band spectrum) of a pulsed plasma generator depending on its axis spatial position, are presented. It is shown that the spatial distribution of plasma radiant intensity is of clearly anisotropic character, that is, there exists a cone of the plasma generator axial directions in which the radiation of plasma reaches its peak. A possible explanation of the results obtained based on a hypothesis of global anisotropy of space caused by the existence of a cosmological vectorial potential A{sub g}, is given. It is shown that the vector A{sub g} has the following coordinates in the second equatorial coordinate system: right ascension {alpha}=293 deg. {+-}10 deg., declination {delta}=36 deg. {+-}10 deg. The experimental results are in accordance with those of the earlier experiments on determining the direction of A{sub g}.

  2. Characterisation of Special Sensor Microwave Water Vapor Profiler (SSM/T-2) radiances using radiative transfer simulations from global atmospheric reanalyses

    Science.gov (United States)

    Kobayashi, Shinya; Poli, Paul; John, Viju O.

    2017-02-01

    The near-global and all-sky coverage of satellite observations from microwave humidity sounders operating in the 183 GHz band complement radiosonde and aircraft observations and satellite infrared clear-sky observations. The Special Sensor Microwave Water Vapor Profiler (SSM/T-2) of the Defense Meteorological Satellite Program began operations late 1991. It has been followed by several other microwave humidity sounders, continuing today. However, expertise and accrued knowledge regarding the SSM/T-2 data record is limited because it has remained underused for climate applications and reanalyses. In this study, SSM/T-2 radiances are characterised using several global atmospheric reanalyses. The European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA-Interim), the first ECMWF reanalysis of the 20th-century (ERA-20C), and the Japanese 55-year Reanalysis (JRA-55) are projected into SSM/T-2 radiance space using a fast radiative transfer model. The present study confirms earlier indications that the polarisation state of SSM/T-2 antenna is horizontal (not vertical) in the limit of nadir viewing. The study also formulates several recommendations to improve use of the SSM/T-2 measurement data in future fundamental climate data records or reanalyses. Recommendations are (1) to correct geolocation errors, especially for DMSP 14; (2) to blacklist poor quality data identified in the paper; (3) to correct for inter-satellite biases, estimated here on the order of 1 K, by applying an inter-satellite recalibration or, for reanalysis, an automated (e.g., variational) bias correction; and (4) to improve precipitating cloud filtering or, for reanalysis, consider an all-sky assimilation scheme where radiative transfer simulations account for the scattering effect of hydrometeors.

  3. Evaluation of cloud fraction and its radiative effect simulated by IPCC AR4 global models against ARM surface observations

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Yun; Long, Charles N.; Wang, Hailong; Comstock, Jennifer M.; McFarlane, Sally A.; Xie, Shaocheng

    2012-02-17

    Cloud Fraction (CF) is the dominant modulator of radiative fluxes. In this study, we evaluate CF simulations in the IPCC AR4 GCMs against ARM ground measurements, with a focus on the vertical structure, total amount of cloud and its effect on cloud shortwave transmissivity, for both inter-model deviation and model-measurement discrepancy. Our intercomparisons of three CF or sky-cover related dataset reveal that the relative differences are usually less than 10% (5%) for multi-year monthly (annual) mean values, while daily differences are quite significant. The results also show that the model-observation and the inter-model deviations have a similar magnitude for the total CF (TCF) and the normalized cloud effect, and they are twice as large as the surface downward solar radiation and cloud transmissivity. This implies that the other cloud properties, such as cloud optical depth and height, have a similar magnitude of disparity to TCF among the GCMs, and suggests that a better agreement among the GCMs in solar radiative fluxes could be the result of compensating errors in either cloud vertical structure, cloud optical depth or cloud fraction. Similar deviation pattern between inter-model and model-measurement suggests that the climate models tend to generate larger bias against observations for those variables with larger inter-model deviation. The simulated TCF from IPCC AR4 GCMs are very scattered through all seasons over three ARM sites: Southern Great Plains (SGP), Manus, Papua New Guinea and North Slope of Alaska (NSA). The GCMs perform better at SGP than at Manus and NSA in simulating the seasonal variation and probability distribution of TCF; however, the TCF in these models is remarkably underpredicted and cloud transmissivity is less susceptible to the change of TCF than the observed at SGP. Much larger inter-model deviation and model bias are found over NSA than the other sites in estimating the TCF, cloud transmissivity and cloud-radiation interaction

  4. Irradiação global, direta e difusa, para a região de Cascavel, Estado do Paraná = Global, direct and diffuse irradiation in the region of Cascavel, Paraná State

    Directory of Open Access Journals (Sweden)

    Patricia Aparecida de Oliveira Drechmer

    2006-01-01

    Full Text Available O presente trabalho apresenta um estudo sobre os níveis das irradiações global, direta e difusa incidentes na superfície terrestre, a irradiação incidente no topo da atmosfera e a insolação relativa mensal, para a cidade de Cascavel-PR. As componentes da radiação solar foram monitoradas entre janeiro de 2001 e fevereiro de 2003 na Estação Experimental Agrometeorológica da Unioeste, Cascavel, Estado do Paraná. Na medição da radiação global foi utilizado um piranômetro KIPP & ZONEN-CM3 e para medir a componente direta foiutilizado um pireliômetro EPPLEY-NIP acoplado a um rastreador solar. A radiação difusa foi calculada pela diferença entre as radiações global e direta. Os níveis médios mensais das irradiações global, direta e difusa, foram respectivamente, 51,8%, 31,7% e 20,17% dairradiação incidente no topo da atmosfera. O índice de insolação relativa apresentou valor máximo em agosto (61,43% e mínimo em fevereiro (34,35%, períodos caracterizados respectivamente por dias de céu limpo e nublados no hemisfério sul.This paper reports a study about the diffuse, direct and global radiation levels on surface of earth, the irradiation over the top of atmosphere and the monthly relative sunstroke in the city of Cascavel, State of Paraná, southern Brazil. The solar radiation components were monitored from January, 2001 to February, 2003 at Estação Experimental Agrometeorológica of Unioeste, Cascavel, Parana State. Global radiation was monitored by a pyranometer KIPP & ZONEN-CM3 and direct radiation was monitored by a pyrheliometer EPPLEY-NIP coupled to a solar tracer. The diffuse radiation wasmonitored through the difference between global and direct radiation. Monthly average levels of global, direct and diffuse irradiations were 51.8%, 31.7% and 20.17% of the irradiation in the top of atmosphere. The relative isolation index showed the maximum value in August (61.43% and the minimum in February (34.35%. These

  5. Global and regional radiative forcing from 20 % reductions in BC, OC and SO4 - an HTAP2 multi-model study

    Science.gov (United States)

    Weum Stjern, Camilla; Hallvard Samset, Bjørn; Myhre, Gunnar; Bian, Huisheng; Chin, Mian; Davila, Yanko; Dentener, Frank; Emmons, Louisa; Flemming, Johannes; Søvde Haslerud, Amund; Henze, Daven; Eiof Jonson, Jan; Kucsera, Tom; Tronstad Lund, Marianne; Schulz, Michael; Sudo, Kengo; Takemura, Toshihiko; Tilmes, Simone

    2016-11-01

    In the Hemispheric Transport of Air Pollution Phase 2 (HTAP2) exercise, a range of global atmospheric general circulation and chemical transport models performed coordinated perturbation experiments with 20 % reductions in emissions of anthropogenic aerosols, or aerosol precursors, in a number of source regions. Here, we compare the resulting changes in the atmospheric load and vertically resolved profiles of black carbon (BC), organic aerosols (OA) and sulfate (SO4) from 10 models that include treatment of aerosols. We use a set of temporally, horizontally and vertically resolved profiles of aerosol forcing efficiency (AFE) to estimate the impact of emission changes in six major source regions on global radiative forcing (RF) pertaining to the direct aerosol effect, finding values between. 51.9 and 210.8 mW m-2 Tg-1 for BC, between -2.4 and -17.9 mW m-2 Tg-1 for OA and between -3.6 and -10.3 W m-2 Tg-1 for SO4. In most cases, the local influence dominates, but results show that mitigations in south and east Asia have substantial impacts on the radiative budget in all investigated receptor regions, especially for BC. In Russia and the Middle East, more than 80 % of the forcing for BC and OA is due to extra-regional emission reductions. Similarly, for North America, BC emissions control in east Asia is found to be more important than domestic mitigations, which is consistent with previous findings. Comparing fully resolved RF calculations to RF estimates based on vertically averaged AFE profiles allows us to quantify the importance of vertical resolution to RF estimates. We find that locally in the source regions, a 20 % emission reduction strengthens the radiative forcing associated with SO4 by 25 % when including the vertical dimension, as the AFE for SO4 is strongest near the surface. Conversely, the local RF from BC weakens by 37 % since BC AFE is low close to the ground. The fraction of BC direct effect forcing attributable to intercontinental transport, on the

  6. Estimativa do saldo de radiação em girassol como função da radiação solar global Estimation of net radiation in sunflower as a function of solar radiation

    Directory of Open Access Journals (Sweden)

    Arno B Heldwein

    2012-02-01

    Full Text Available Objetivou-se com este trabalho a obtenção de modelos para a estimativa do saldo de radiação (Q* a partir da radiação solar global incidente (Rg sobre dosseis de plantas de girassol. Os experimentos foram conduzidos na área experimental da Universidade Federal de Santa Maria, nos anos de 2007, 2008 e 2009. O Q* foi medido com saldos radiômetros instalados acima das plantas e a Rg em estações meteorológicas automáticas. Para fins de cálculo foram efetuadas as somas diárias de Q* e de Rg, obtendo-se a relação entre Q* e Rg para cada dia. Obtiveram-se, então, modelos com elevado coeficiente de determinação e baixo RQME no teste entre valores medidos e estimados de um banco de dados independente, indicando precisão na estimativa do saldo de radiação em dosseis de girassol, independendo da época de cultivo no ano. A função linear geral obtida com dados de diferentes épocas de cultivo foi: Q* = 0,5285 Rg (R² = 0,95, que no teste apresentou RQME = 1,04 MJ m-2 d-1. Conclui-se que o saldo de radiação (Q* pode ser estimado utilizando-se a radiação solar global medida em estações automáticas, com precisão suficiente para os diferentes fins na agrometeorologia do girassol.This study aimed to develop models for estimating the net radiation (Q * from the incident solar radiation (Rg on canopies of sunflower plants. The experiments were conducted at the Plant Science Department of the Federal University of Santa Maria in 2007, 2008 and 2009 years. Q* was measured by net radiometers above the plants and Rg by automatic weather stations. For purposes of calculation, daily sums of Q* and Rg were performed, obtaining the relationship between Q* and Rg for each day. Models with high coefficient of determination and low RQME were obtained in test between measured and estimated values from an independent database, indicating precision to estimate net radiation in sunflower canopies, regardless of cultivation time in year. The general

  7. IrrE, a global regulator of extreme radiation resistance in Deinococcus radiodurans, enhances salt tolerance in Escherichia coli and Brassica napus.

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    Jie Pan

    Full Text Available BACKGROUND: Globally, about 20% of cultivated land is now affected by salinity. Salt tolerance is a trait of importance to all crops in saline soils. Previous efforts to improve salt tolerance in crop plants have met with only limited success. Bacteria of the genus Deinococcus are known for their ability to survive highly stressful conditions, and therefore possess a unique pool of genes conferring extreme resistance. In Deinococcus radiodurans, the irrE gene encodes a global regulator responsible for extreme radioresistance. METHODOLOGY/PRINCIPAL FINDINGS: Using plate assays, we showed that IrrE protected E. coli cells against salt shock and other abiotic stresses such as oxidative, osmotic and thermal shocks. Comparative proteomic analysis revealed that IrrE functions as a switch to regulate different sets of proteins such as stress responsive proteins, protein kinases, glycerol-degrading enzymes, detoxification proteins, and growth-related proteins in E. coli. We also used quantitative RT-PCR to investigate expression of nine selected stress-responsive genes in transgenic and wild-type Brassica napus plants. Transgenic B. napus plants expressing the IrrE protein can tolerate 350 mM NaCl, a concentration that inhibits the growth of almost all crop plants. CONCLUSIONS: Expression of IrrE, a global regulator for extreme radiation resistance in D. radiodurans, confers significantly enhanced salt tolerance in both E. coli and B. napus. We thus propose that the irrE gene might be used as a potentially promising transgene to improve abiotic stress tolerances in crop plants.

  8. Global emission estimates and radiative impact of C4F10, C5F12, C6F14, C7F16 and C8F18

    Directory of Open Access Journals (Sweden)

    R. G. Prinn

    2012-05-01

    7F16 and C8F18, and estimate their radiative efficiencies and global warming potentials (GWPs. We find that C8F18's radiative efficiency is similar to trifluoromethyl sulfur pentafluoride's (SF5CF3 at 0.57 W m−2 ppb−1, which is the highest radiative efficiency of any measured atmospheric species. Using the 100-yr time horizon GWPs, the high molecular weight perfluorocarbons studied here contributed up to 15.4% of the total PFC emissions in CO2 equivalents in 1997 and 6% of the total PFC emissions in 2009.

  9. Coronal heating and wind acceleration by nonlinear Alfvén waves – global simulations with gravity, radiation, and conduction

    Directory of Open Access Journals (Sweden)

    T. K. Suzuki

    2008-03-01

    Full Text Available We review our recent results of global one-dimensional (1-D MHD simulations for the acceleration of solar and stellar winds. We impose transverse photospheric motions corresponding to the granulations, which generate outgoing Alfvén waves. We treat the propagation and dissipation of the Alfvén waves and consequent heating from the photosphere by dynamical simulations in a self-consistent manner. Nonlinear dissipation of Alfven waves becomes quite effective owing to the stratification of the atmosphere (the outward decrease of the density. We show that the coronal heating and the solar wind acceleration in the open magnetic field regions are natural consequence of the footpoint fluctuations of the magnetic fields at the surface (photosphere. We find that the properties of the solar wind sensitively depend on the fluctuation amplitudes at the solar surface because of the nonlinearity of the Alfvén waves, and that the wind speed at 1 AU is mainly controlled by the field strength and geometry of flux tubes. Based on these results, we point out that both fast and slow solar winds can be explained by the dissipation of nonlinear Alfvén waves in a unified manner. We also discuss winds from red giant stars driven by Alfvén waves, focusing on different aspects from the solar wind.

  10. Exploiting simultaneous observational constraints on mass and absorption to estimate the global direct radiative forcing of black carbon and brown carbon

    Science.gov (United States)

    Wang, X.; Heald, C. L.; Ridley, D. A.; Schwarz, J. P.; Spackman, J. R.; Perring, A. E.; Coe, H.; Liu, D.; Clarke, A. D.

    2014-10-01

    Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand a global model simulation (GEOS-Chem) of BC to include the absorption enhancement associated with BC coating and separately treat both the aging and physical properties of fossil-fuel and biomass-burning BC. In addition we develop a global simulation of brown carbon (BrC) from both secondary (aromatic) and primary (biomass burning and biofuel) sources. The global mean lifetime of BC in this simulation (4.4 days) is substantially lower compared to the AeroCom I model means (7.3 days), and as a result, this model captures both the mass concentrations measured in near-source airborne field campaigns (ARCTAS, EUCAARI) and surface sites within 30%, and in remote regions (HIPPO) within a factor of 2. We show that the new BC optical properties together with the inclusion of BrC reduces the model bias in absorption aerosol optical depth (AAOD) at multiple wavelengths by more than 50% at AERONET sites worldwide. However our improved model still underestimates AAOD by a factor of 1.4 to 2.8 regionally, with the largest underestimates in regions influenced by fire. Using the RRTMG model integrated with GEOS-Chem we estimate that the all-sky top-of-atmosphere DRF of BC is +0.13 Wm-2 (0.08 Wm-2 from anthropogenic sources and 0.05 Wm-2 from biomass burning). If we scale our model to match AERONET AAOD observations we estimate the DRF of BC is +0.21 Wm-2, with an additional +0.11 Wm-2 of warming from BrC. Uncertainties in size, optical properties, observations, and emissions suggest an overall uncertainty in BC DRF of -80%/+140%. Our estimates are at the lower end of the 0.2-1.0 Wm-2 range from previous studies, and substantially less than the +0.6 Wm-2 DRF estimated in the IPCC 5th Assessment Report. We suggest that the DRF of BC has previously been overestimated due to the overestimation of the BC lifetime (including the

  11. When do Acacia mellifera trees use water? Responses of sap velocity to soil water availability, vapour pressure deficit and global radiation.

    Science.gov (United States)

    de Blécourt, Marleen; Thomsen, Simon; Gröngröft, Alexander; Eschenbach, Annette

    2017-04-01

    Acacia mellifera (multi-stem deciduous tree) is one of the dominant woody species responsible for bush encroachment in southern African savannahs. However, very little is known on water use, transpiration or xylem sap flow of A. mellifera. We analyzed the responses of sap velocity in A. mellifera to soil moisture, vapour pressure deficit and global radiation. This knowledge is necessary to improve hydrological modelling and will as such contribute to our understanding of the impacts of bush encroachment in (semi) arid savannahs on the soil water balance. We monitored sap velocities at two sites that differed in tree density in a semi-arid thornbush savannah in central Namibia (mean annual precipitation = 346 mm). Sap velocities were derived using the Heat Ratio Method. Measurements were done in four periods of 3-4 months between November 2014 and September 2016. The measurement periods covered the transitions between the dry and rainy season and vice versa, and the dry season. In two of these periods we did measurements at all stems of three trees per site (a total of 17-19 stems), while in the other two periods sap velocities were measured on one stem per tree for six to eight trees per site. The study was done in the framework of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management) granted by the German Federal Ministry of Education and Research (BMBF). Preliminary results indicate that the day-to-day fluctuations in cumulative daily sap velocity showed a three-phase interaction with soil water tension (minimum soil water tension of four sensors to 1-m depth). Phase I: At soil water tension radiation. Phase II: At soil water tensions between pF 2.5 and pF 3.2, sap velocities were negatively related to soil water tension. Phase III: At soil water tensions > pF 3.2 no sap flow could be detected.

  12. Shortwave direct radiative effects of above-cloud aerosols over global oceans derived from 8 years of CALIOP and MODIS observations

    Science.gov (United States)

    Zhang, Zhibo; Meyer, Kerry; Yu, Hongbin; Platnick, Steven; Colarco, Peter; Liu, Zhaoyan; Oreopoulos, Lazaros

    2016-03-01

    In this paper, we studied the frequency of occurrence and shortwave direct radiative effects (DREs) of above-cloud aerosols (ACAs) over global oceans using 8 years (2007-2014) of collocated CALIOP and MODIS observations. Similar to previous work, we found high ACA occurrence in four regions: southeastern (SE) Atlantic region, where ACAs are mostly light-absorbing aerosols, i.e., smoke and polluted dust according to CALIOP classification, originating from biomass burning over the African Savanna; tropical northeastern (TNE) Atlantic and the Arabian Sea, where ACAs are predominantly windblown dust from the Sahara and Arabian deserts, respectively; and the northwestern (NW) Pacific, where ACAs are mostly transported smoke and polluted dusts from Asian. From radiative transfer simulations based on CALIOP-MODIS observations and a set of the preselected aerosol optical models, we found the DREs of ACAs at the top of atmosphere (TOA) to be positive (i.e., warming) in the SE Atlantic and NW Pacific regions, but negative (i.e., cooling) in the TNE Atlantic Ocean and the Arabian Sea. The cancellation of positive and negative regional DREs results in a global ocean annual mean diurnally averaged cloudy-sky DRE of 0.015 W m-2 (range of -0.03 to 0.06 W m-2) at TOA. The DREs at surface and within the atmosphere are -0.15 W m-2 (range of -0.09 to -0.21 W m-2), and 0.17 W m-2 (range of 0.11 to 0.24 W m-2), respectively. The regional and seasonal mean DREs are much stronger. For example, in the SE Atlantic region, the JJA (July-August) seasonal mean cloudy-sky DRE is about 0.7 W m-2 (range of 0.2 to 1.2 W m-2) at TOA. All our DRE computations are publicly available1. The uncertainty in our DRE computations is mainly caused by the uncertainties in the aerosol optical properties, in particular aerosol absorption, the uncertainties in the CALIOP operational aerosol optical thickness retrieval, and the ignorance of cloud and potential aerosol diurnal cycle. In situ and remotely sensed

  13. Shortwave Direct Radiative Effects of Above-Cloud Aerosols Over Global Oceans Derived From 8 Years of CALIOP and MODIS Observations

    Science.gov (United States)

    Zhang, Zhibo; Meyer, Kerry; Yu, Hongbin; Platnick, Steven; Colarco, Peter; Liu, Zhaoyan; Oraiopoulos, Lazaros

    2016-01-01

    In this paper, we studied the frequency of occurrence and shortwave direct radiative effects (DREs) of above-cloud aerosols (ACAs) over global oceans using 8 years (2007-2014) of collocated CALIOP and MODIS observations. Similar to previous work, we found high ACA occurrence in four regions: southeastern (SE) Atlantic region, where ACAs are mostly light-absorbing aerosols, i.e., smoke and polluted dust according to CALIOP classification, originating from biomass burning over the African Savanna; tropical northeastern (TNE) Atlantic and the Arabian Sea, where ACAs are predominantly windblown dust from the Sahara and Arabian deserts, respectively; and the northwestern (NW) Pacific, where ACAs are mostly transported smoke and polluted dusts from Asia. From radiative transfer simulations based on CALIOP-MODIS observations and a set of the preselected aerosol optical models, we found the DREs of ACAs at the top of atmosphere (TOA) to be positive (i.e., warming) in the SE Atlantic and NW Pacific regions, but negative (i.e., cooling) in the TNE Atlantic Ocean and the Arabian Sea. The cancellation of positive and negative regional DREs results in a global ocean annual mean diurnally averaged cloudy-sky DRE of 0.015 W m(exp. -2) [range of -0.03 to 0.06 W m (exp. -2)] at TOA. The DREs at surface and within the atmosphere are -0.015 W m(exp. -2) [range of -0.09 to -0.21 W m(exp. -2)], and 0.17 W m(exp. -2) [range of 0.11 to 0.24 W m(exp. -2)], respectively. The regional and seasonal mean DREs are much stronger. For example, in the SE Atlantic region, the JJA (July-August) seasonal mean cloudy-sky DRE is about 0.7 W m(exp. -2) [range of 0.2 to 1.2 W m(exp. -2)] at TOA. All our DRE computations are publicly available. The uncertainty in our DRE computations is mainly caused by the uncertainties in the aerosol optical properties, in particular aerosol absorption, the uncertainties in the CALIOP operational aerosol optical thickness retrieval, and the ignorance of cloud and

  14. Generalized models for estimation of diffuse solar radiation based on clearness index and sunshine duration in India: Applicability under different climatic zones

    Science.gov (United States)

    Jamil, Basharat; Siddiqui, Abid T.

    2017-05-01

    Generalized models for assessment of monthly average diffuse solar radiation over India were established using long-term solar radiation data available for 15 years (1986-2000) obtained from Indian Meteorological Department (IMD), Pune. Regression analysis was employed to correlate the diffuse fraction (K̅d) with clearness index (K̅t) and relative sunshine period (S̅/S̅o) together. Seven new models (with two input variables i.e. global solar radiation and relative sunshine period) were developed using data of the measurement sites. Well-established models from literature were also compared with the proposed models. Statistical tests used to evaluate the accuracy of models were mean bias error, root mean square error, mean percentage error, coefficient of determination, t-statistics and normalized median absolute deviation. Global performance indicator (GPI) was used to rank the models. Further, the empirical models were applied on the five representative locations under diverse climatic zones (i.e. Hot & Dry, Warm & Humid, Temperate, Cold and Composite climates) prescribed by the Energy Conservation Building Code (ECBC) for India. Proposed models were also compared within each climatic zone and best model was recommended. Developed models were found to have good performance on collective data as well as under each climatic zone individually.

  15. Significant Findings: Seasonal Distributions of Global Ocean Chlorophyll and Nutrients With a Coupled Ocean General Circulation, Biogeochemical, and Radiative Model. 2; Comparisons With Satellite and In Situ Data

    Science.gov (United States)

    Gregg, Watson W.; Busalacchi, Antonio (Technical Monitor)

    2000-01-01

    A coupled ocean general circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. Biogeochemical processes in the model were determined from the influences of circulation and turbulence dynamics, irradiance availability, and the interactions among three functional phytoplankton groups (diatoms, chlorophytes, and picoplankton) and three nutrients (nitrate, ammonium, and silicate). Basin scale (>1000 km) model chlorophyll seasonal distributions were statistically positively correlated with CZCS chlorophyll in 10 of 12 major oceanographic regions, and with SeaWiFS in all 12. Notable disparities in magnitudes occurred, however, in the tropical Pacific, the spring/summer bloom in the Antarctic, autumn in the northern high latitudes, and during the southwest monsoon in the North Indian Ocean. Synoptic scale (100-1000 km) comparisons of satellite and in situ data exhibited broad agreement, although occasional departures were apparent. Model nitrate distributions agreed with in situ data, including seasonal dynamics, except for the equatorial Atlantic. The overall agreement of the model with satellite and in situ data sources indicated that the model dynamics offer a reasonably realistic simulation of phytoplankton and nutrient dynamics on basin and synoptic scales.

  16. Spatial Distribution of Global Solar Radiation in Huang-Huai-Hai Region over Rugged Terrain%起伏地形下黄淮海地区太阳总辐射的空间分布研究

    Institute of Scientific and Technical Information of China (English)

    张峰; 胡波

    2013-01-01

    太阳辐射是地球上最基本最重要的能源,它的变化影响着温度、湿度、降水和大气环流特征等的变化.利用MTCLIM模型模拟了起伏地形下黄淮海地区年太阳辐射总量的空间分布状况,结果表明,在黄淮海地区,年太阳辐射总量的分布大体上呈现由西北向东南的递减趋势;太阳总辐射高值区位于黄淮海地区的西北部和西南少部分地区,低值中心则在沿海地区;影响太阳总辐射的因素主要包括地形地势、气候、纬度高低等方面.该研究可为其他地区太阳总辐射空间分布研究提供方法和技术参考,研究结果可为合理高效利用黄淮海地区的太阳总辐射能源提供科学依据.%Solar radiation is the most basic and important energy on the earth. Its change affected the changes of temperature, humidity, precipitation and atmosphere circulation characteristics. The spatial distribution of annual global solar radiation in Huang-Huai-Hai region over rugged terrain was simulated by using the MTCLIM Model. The results showed that; the distribution of global solar radiation is showing a decreasing trend from the northwest to the southeast in Huang-Huai-Hai region; the high-value area of global solar radiation are located in the northwest and small parts of southwest in Huang-Huai-Hai region, and the low-value area are located in the coastal areas; the influential factors of global solar radiation mainly include topography, amplitude, climate, and latitude. The research can provide method and reference for the spatial distribution of global solar radiation in other regions, also can provide scientific basis for reasonable and efficient utilization of solar radiation energy in Huang-Huai-Hai region.

  17. Long-term variations of estimated global solar radiation and the influencing factors in Hunan province, China during 1980-2013

    Science.gov (United States)

    Zou, Ling; Lin, Aiwen; Wang, Lunche; Xia, Xiangao; Gong, Wei; Zhu, Hongji; Zhao, Zhenzhen

    2016-04-01

    Long-term variation of estimated global solar radiation (E g↓) and its relationship with total cloud cover (TCC), low cloud cover (LCC), water vapor content (WVC) and aerosol optical depth (AOD) were investigated based on the observations at 21 meteorological stations in Hunan province, China. Long-term variations of all variables were calculated for each station; the Mann-Kendall trend test was used to detect the significant level of temporal development trend for each variable; the Pearson correlation analysis was used to measure their linear relationships. Annual E g↓ generally decreased at the rate of -2.11 × 10-3 MJ m-2 decade-1 in Hunan province during 1980-2013. Seasonal mean E g↓ decreased at the rate of -11.99 × 10-3, -4.71 × 10-3 and -4.51 × 10-3 MJ m-2 decade-1 in summer, autumn and winter, respectively, while the increasing trend was observed in spring (15.74 × 10-3 MJ m-2 decade-1). The annual variation of E g↓ in Hunan province was dominantly determined by the variations of AOD (0.33 × 10-3 decade-1) and LCC (0.24 % p decade-1). But the spatial variation of E g↓ in Hunan province was complex. All 21 stations were divided into four groups according to the long-term trends of E g↓, TCC, LCC, AOD and WVC. An increasing E g↓ was observed at stations in group 1, which was determined by the variability of TCC. The variability of AOD and TCC might contribute to the increasing E g↓ in group 2. There were decreasing trends of E g↓ for the stations in group 3 and group 4, which were largely determined by the increases of AOD and LCC.

  18. Variability analysis of the reconstructed daily global solar radiation under all-sky and cloud-free conditions in Madrid during the period 1887-1950

    Science.gov (United States)

    Antón, M.; Román, R.; Sanchez-Lorenzo, A.; Calbó, J.; Vaquero, J. M.

    2017-07-01

    This study focuses on the analysis of the daily global solar radiation (GSR) reconstructed from sunshine duration measurements at Madrid (Spain) from 1887 to 1950. Additionally, cloud cover information recorded simultaneously by human observations for the study period was also analyzed and used to select cloud-free days. First, the day-to-day variability of reconstructed GSR data was evaluated, finding a strong relationship between GSR and cloudiness. The second step was to analyze the long-term evolution of the GSR data which exhibited two clear trends with opposite sign: a marked negative trend of - 36 kJ/m2 per year for 1887-1915 period and a moderate positive trend of + 13 kJ/m2 per year for 1916-1950 period, both statistically significant at the 95% confidence level. Therefore, there is evidence of ;early dimming; and ;early brightening; periods in the reconstructed GSR data for all-sky conditions in Madrid from the late 19th to the mid-20th centuries. Unlike the long-term evolution of GSR data, cloud cover showed non-statistically significant trends for the two analyzed sub-periods, 1887-1915 and 1916-1950. Finally, GSR trends were analyzed exclusively under cloud-free conditions in summer by means of the determination of the clearness index for those days with all cloud cover observations equal to zero oktas. The long-term evolution of the clearness index was in accordance with the ;early dimming; and ;early brightening; periods, showing smaller trends but still statistically significant. This result points out that aerosol load variability could have had a non-negligible influence on the long-term evolution of GSR even as far as from the late 19th century.

  19. The Site-Directed A184S Mutation in the HTH Domain of the Global Regulator IrrE Enhances Deinococcus radiodurans R1 Tolerance to UV Radiation and MMC Shock.

    Science.gov (United States)

    Zhang, Chen; Zhou, Zhengfu; Zhang, Wei; Chen, Zhen; Song, Yuan; Lu, Wei; Lin, Min; Chen, Ming

    2015-12-28

    IrrE is a highly conserved global regulator in the Deinococcus genus and contributes to survival from high doses of UV radiation, ionizing radiation, and desiccation. Drad-IrrE and Dgob-IrrE from Deinococcus radiodurans and Deinococcus gobiensis I-0 each share 66% sequence identity. However, Dgob-IrrE showed a stronger protection phenotype against UV radiation than Drad- IrrE in the D. radiodurans irrE-deletion mutant (ΔirrE), which may be due to amino acid residues differences around the DNA-binding HTH domain. Site-directed mutagenesis was used to generate a Drad-IrrE A184S single mutant, which has been characterized and compared with the ΔirrE mutant complemented strain with Drad-irrE, designated ΔirrE-E. The effects of the A184S mutation following UV radiation and mitomycin C (MMC) shock were determined. The A184S mutant displayed significantly increased resistance to UV radiation and MMC shock. The corresponding A184 site in Dgob-IrrE was inversely mutated, generating the S131A mutant, which exhibited a loss of resistance against UV radiation, MMC shock, and desiccation. qPCR analysis revealed that critical genes in the DNA repair system, such as recA, pprA, uvrA, and ddrB, were remarkably induced after UV radiation and MMC shock in the ΔirrE-IE and A184S mutants. These data suggested that A184S improves the ability against UV radiation and MMC shock, providing new insights into the modification of IrrE. We speculated that the serine residue may determine the efficiency of DNA binding, leading to the increased expression of IrrE-dependent genes important for protection against DNA damage.

  20. Estimation of Solar Radiation in South Eastern Nigeria | Nwokocha ...

    African Journals Online (AJOL)

    Estimation of Solar Radiation in South Eastern Nigeria. ... Knowledge of global solar radiation is of fundamental importance for all solar energy conversion ... the Sayigh equation for estimating the global solar radiation, analyzing data from ...

  1. Solar radiation models - review

    Directory of Open Access Journals (Sweden)

    M. Jamil Ahmad, G.N. Tiwari

    2010-05-01

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

  2. Surface radiation budget in the Clouds and the Earth's Radiant Energy System (CERES) effort and in the Global Energy and Water Cycle Experiment (GEWEX)

    Science.gov (United States)

    Charlock, Thomas P.; Smith, G. L.; Rose, Fred G.

    1990-01-01

    The surface radiation budget (SRB) and the atmospheric radiative flux divergence (ARD) are vital components of the weather and climate system. The importance of radiation in a complex international scientific endeavor, the GEWEX of the World Climate Research Programme is explained. The radiative transfer techniques and satellite instrumentation that will be used to retrieve the SRB and ARD later in this decade with the CERES are discussed; CERES is a component of the Earth Observing System satellite program. Examples of consistent SRB and ARD retrievals made with Nimbus-7 and International Satellite Cloud Climatology Project data from July 1983 are presented.

  3. Global sensitivity analysis of Leaf-Canopy radiative transfer Model for analysis and quantification of uncertainties in remote sensed data product generation

    Science.gov (United States)

    Furfaro, R.; Morris, R. D.; Kottas, A.; Taddy, M.; Ganapol, B. D.

    2007-12-01

    Analyzing, quantifying and reporting the uncertainty in remote sensed data products is critical for our understanding of Earth's coupled system. It is the only way in which the uncertainty of further analyses using these data products as inputs can be quantified. Analyzing the source of the data product uncertainties can identify where the models must be improved, or where better input information must be obtained. Here we focus on developing a probabilistic framework for analysis of uncertainties occurring when satellite data (e.g., MODIS) are employed to retrieve biophysical properties of vegetation. Indeed, the process of remotely estimating vegetation properties involves inverting a Radiative Transfer Model (RTM), as in the case of the MOD15 algorithm where seven atmospherically corrected reflectance factors are ingested and compared to a set of computed, RTM-based, reflectances (look-up table) to infer the Leaf Area Index (LAI). Since inversion is generally ill-conditioned, and since a-priori information is important in constraining the inverse model, sensitivity analysis plays a key role in defining which parameters have the greatest impact to the computed observation. We develop a framework to perform global sensitivity analysis, i.e., to determine how the output changes as all inputs vary continuously. We used a coupled Leaf-Canopy radiative transfer Model (LCM) to approximate the functional relationship between the observed reflectance and vegetation biophysical parameters. LCM was designed to study the feasibility of detecting leaf/canopy biochemistry using remote sensed observations and has the unique capability to include leaf biochemistry (e.g., chlorophyll, water, lignin, protein) as input parameters. The influence of LCM input parameters (including canopy morphological and biochemical parameters) on the hemispherical reflectance is captured by computing the "main effects", which give information about the influence of each input, and the "sensitivity

  4. Variabilidade sazonal da relação entre a radiação fotossinteticamente ativa e a radiação global na bacia do rio Doce, Estado de Minas Gerais = Seasonal variability of the relationship between the photosynthetically active radiation and the global radiation at the river Doce basin, Minas Gerais State

    Directory of Open Access Journals (Sweden)

    Antonio José Steidle Neto

    2006-07-01

    Full Text Available O conhecimento da Radiação Fotossinteticamente Ativa (RFA é importante para diferentes áreas relacionadas à fisiologia vegetal e ciências agrárias. Modelos de estimativa de RFA a partir da Radiação Global (Rg são extremamente úteis, visto que a Rg é convencionalmente medida nas estações meteorológicas. Assim, analisou-se a variabilidade sazonal da relação RFA/Rg em cinco áreas localizadas na bacia do rio Doce, Estado de Minas Gerais, considerando-se os períodos secos e chuvosos dos anos de 2001 a 2004. As relações RFA/Rg obtidas para os períodos secos e chuvosos, assim como para todos os dados, apresentaram concordância com as relações determinadas por diversos pesquisadores em diferentes áreas do mundo. Analisando-se os resultados, constatou-se que, de maneira geral,as relações RFA/Rg tendem a ser superiores durante os períodos chuvosos comparativamente aos secos. Por este estudo, pôde-se concluir que existe variação interanual desta relação, demonstrando assim a necessidade de se considerar esta variabilidade para estimaradequadamente a RFA a partir da Rg. The knowledge of the Photosynthetically Active Radiation (PAR is important to different areas of vegetal physiology and agricultural sciences. Estimation models of the PAR based on the Global Radiation (GR are extremely useful, since the GR is conventionally measured atthe meteorological stations. Thus, the seasonal variability of the relationship PAR/GR was analyzed in five areas located at the river Doce basin, Minas Gerais State, Brazil, considering the dry and wet periods of the years 2001 to 2004. The relationships PAR/GR obtained for the dry and wet periods, and also to all data, presented agreement with those ones determined by several researchers in different areas of the world. Results showed that the relationshipsPAR/GR generally tend to be greater during the wet periods when compared with the dry ones. By this work, it could be concluded that

  5. Seasonal Variation in Monthly Average Air Change Rates Using Passive Tracer Gas Measurements

    DEFF Research Database (Denmark)

    Frederiksen, Marie; Bergsøe, Niels Christian; Kolarik, Barbara

    2011-01-01

    Indoor air quality in dwellings is largely determined by the air change rate (ACR) and the magnitude of indoor air pollution sources. Concurrently, great efforts are made to make buildings energy efficient, which may result in low ACRs. In the present study, the monthly ACR averages were measured...

  6. CHAMP climate data based on the inversion of monthly average bending angles

    Directory of Open Access Journals (Sweden)

    J. Danzer

    2014-12-01

    Exploitation of Meteorological Satellites Radio Occultation Meteorology Satellite Application Facility (ROM SAF operational processing. In this study it is demonstrated that the API retrieval technique works well for CHAMP data, enabling the generation of long-term stratospheric RO climate data records from August 2001 and onward. The resulting CHAMP refractivity climatologies are found to be practically identical to the standard retrieval at the DMI (Danish Meteorological Institute below altitudes of 35 km. Between 35 and 50 km, the differences between the two retrieval methods started to increase, showing largest differences at high latitudes and high altitudes. Furthermore, in the winter hemisphere high-latitude region, the biases relative to ECMWF (European Centre for Medium-range Weather Forecasts were generally smaller for the new approach than for the standard retrieval.

  7. Razão entre radiação fotossinteticamente ativa e radiação global no cultivo do tomateiro em casa-de-vegetação Ratio between photosynthetically active radiation and global radiation during tomato growth inside greenhouse

    Directory of Open Access Journals (Sweden)

    Antonio J. Steidle Neto

    2008-12-01

    Full Text Available Propôs-se, com este trabalho, determinar e analisar as variações da razão entre a radiação fotossinteticamente ativa (RFA e a radiação global (Rg durante o período de crescimento do tomateiro (Lycopersicon esculentum Mill., cv. Duradoro cultivado em substrato de areia sob condições de ambiente protegido. Medições de Rg e RFA foram conduzidas no interior de uma casa-de-vegetação, coberta com filme plástico de polietileno, durante a estação seca, em Viçosa, MG. Paralelamente, a Rg foi medida também em uma estação meteorológica automática. A razão RFA/Rg sofreu uma redução de 1,691 para 1,574 mol MJ-1, no período compreendido entre as 1ª e 9ª semanas após o transplante e se manteve praticamente estável entre as 9ª e 13ª semanas, oscilando entre 1,571 e 1,587 mol MJ-1. Posteriormente, com a ocorrência da alternância de condições de céu claro para dias nublados, a RFA/Rg sofreu aumentos consideráveis (1,93 e 2,07 mol MJ-1, os quais estão próximos dos obtidos em outras localidades do Brasil. Com base nos resultados, é possível afirmar que ocorreu efeito pouco expressivo da expansão foliar da cultura em reflexões múltiplas da radiação solar no interior do ambiente protegido e um efeito marcante da nebulosidade na razão RFA/Rg.It was proposed in this study to determine and analyze variations in the ratio between photosynthetically active radiation (PAR and global solar radiation (GR during the growth season of tomato (Lycopersicon esculentum Mill., cv. Duradoro crop in sand substract under protected cultivation. Measurements of GR and PAR were conducted inside of a single layer polyethylene greenhouse during the dry season in Viçosa, Minas Gerais, Brazil. Simultaneously, the GR was measured in an automatic weather station. The PAR/GR ratio decreased from 1.691 to 1.574 mol MJ-1, from the first to the ninth week after transplanting, and was relatively constant, oscillating between 1.571 and 1.587 from

  8. Calibration of the Ångström-Prescott coefficients (a, b) under different time scales and their impacts in estimating global solar radiation in the Yellow River basin

    DEFF Research Database (Denmark)

    Liu, Xiaoyling; Mei, Xurong; Li, Yuzhong

    2009-01-01

    The Ångström-Prescott (A-P) equation relating in its current form the incident top-of-atmosphere solar radiation to the solar radiation received at the surface, is one of the most accurate and widely used sunshine-based methods estimating global solar radiation (Rs). The key in its application is...... higher a and lower b and larger variations over those using daily data. At yearly time scale, the sunshine-radiation relationship can no longer be described by the linear A-P formula. The difference in coefficients between daily and monthly calibration was rather large accounting for 71...... location. However, the large effect of time scales on a and b produced no significant impact on the estimation accuracy of Rs because of the conservative response of the sum a + b to time scale. In this sense, the coefficients calibrated at daily scale are interchangeable with those calibrated at monthly...... scale, indicating the high flexibility of the A-P formula. Nevertheless, calibration made at daily scale has two important advantages over monthly scale in that it requires fewer years' data to obtain stabilized coefficients, and that it is easily predicted more accurately with common site information...

  9. Assessment of BSRN radiation records for the computation of monthly means

    Directory of Open Access Journals (Sweden)

    A. Roesch

    2011-02-01

    Full Text Available The integrity of the Baseline Surface Radiation Network (BSRN radiation monthly averages are assessed by investigating the impact on monthly means due to the frequency of data gaps caused by missing or discarded high time resolution data. The monthly statistics, especially means, are considered to be important and useful values for climate research, model performance evaluations and for assessing the quality of satellite (time- and space-averaged data products. The study investigates the spread in different algorithms that have been applied for the computation of monthly means from 1-min values.

    The paper reveals that the computation of monthly means from 1-min observations distinctly depends on the method utilized to account for the missing data. The intra-method difference generally increases with an increasing fraction of missing data. We found that a substantial fraction of the radiation fluxes observed at BSRN sites is either missing or flagged as questionable. The percentage of missing data is 4.4%, 13.0%, and 6.5% for global radiation, direct shortwave radiation, and downwelling longwave radiation, respectively. Most flagged data in the shortwave are due to nighttime instrumental noise and can reasonably be set to zero after correcting for thermal offsets in the daytime data. The study demonstrates that the handling of flagged data clearly impacts on monthly mean estimates obtained with different methods. We showed that the spread of monthly shortwave fluxes is generally clearly higher than for downwelling longwave radiation.

    Overall, BSRN observations provide sufficient accuracy and completeness for reliable estimates of monthly mean values. However, the value of future data could be further increased by reducing the frequency of data gaps and the number of outliers. It is shown that two independent methods for accounting for the diurnal and seasonal variations in the missing data permit consistent monthly means to

  10. Global atmospheric changes.

    OpenAIRE

    Piver, W T

    1991-01-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the proces...

  11. Transgenerational Radiation Epigenetics

    Science.gov (United States)

    2014-11-01

    showed altered expression in normal lung from F3 mice. Thus, traces of the effects of a single dose of radiation during development persist into...radiation showed a loss of global cytosine methylation in DNA from thymus , implicating profound epigenetic dysregulation (Tawa et al., 1998; Pogribny...for the carcinogenic and transgenerational effects of radiation. It is also anticipated that these epigenetic signatures will be developed as

  12. Relative Accuracy of 1-Minute and Daily Total Solar Radiation Data for 12 Global and 4 Direct Beam Solar Radiometers: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Myers, D. R.; Wilcox, S. M.

    2009-03-01

    This report evaluates the relative performance of 12 global and four direct beam solar radiometers deployed at a single site over a 12-month period. Test radiometer irradiances were compared with a reference irradiance consisting of either an absolute cavity radiometer (during calibrations) or a low uncertainty thermopile pyrheliometer (during the evaluation period) for pyrheliometers; and for pyranometers a reference global irradiance computed from the reference pyrheliometer and diffuse irradiance from a shaded pyranometer.

  13. DOENÇA RESPIRATÓRIA E SUA RELAÇÃO COM RADIAÇÃO SOLAR GLOBAL, RADIAÇÃO EXTRATERRESTRE, RADIAÇÃO UV E ÍNDICE DE LIMPIDEZ ATMOSFÉRICO / RESPIRATORY DISEASE AND ITS RELATIONSHIP WITH GLOBAL SOLAR RADIATION, EXTRATERRESTRIAL RADIATION, RADIATION AND UV INDEX CLARITY ATMOSPHERIC

    OpenAIRE

    SOUZA, AMAURY DE; ORLANDO SOUZA E AFANI DURUIGAN DE SOUZA

    2010-01-01

    Mudanças climáticas têm sido correlacionadas com variações na composição química da atmosfera e com a emissão e deposição de poluentes na superfície terrestre e seu impacto em doenças respiratórias. Os objetivos desse trabalho são de estudar o comportamento da radiação solar global, extraterrestre e índice de ultravioleta; calcular o índice de limpidez; observar a freqüência de dias claros com base nos valores do índice de limpidez e fazer uma correlação com a concentração de ozônio de superf...

  14. Ultra-violet radiation is responsible for the differences in global epidemiology of chickenpox and the evolution of varicella-zoster virus as man migrated out of Africa

    Directory of Open Access Journals (Sweden)

    Rice Philip S

    2011-04-01

    Full Text Available Abstract Background Of the eight human herpes viruses, varicella-zoster virus, which causes chickenpox and zoster, has a unique epidemiology. Primary infection is much less common in children in the tropics compared with temperate areas. This results in increased adult susceptibility causing outbreaks, for example in health-care workers migrating from tropical to temperate countries. The recent demonstration that there are different genotypes of varicella-zoster virus and their geographic segregation into tropical and temperate areas suggests a distinct, yet previously unconsidered climatic factor may be responsible for both the clinical and molecular epidemiological features of this virus infection. Presentation of the hypothesis Unlike other human herpes viruses, varicella-zoster virus does not require intimate contact for infection to occur indicating that transmission may be interrupted by a geographically restricted climatic factor. The factor with the largest difference between tropical and temperate zones is ultra-violet radiation. This could reduce the infectiousness of chickenpox cases by inactivating virus in vesicles, before or after rupture. This would explain decreased transmissibility in the tropics and why the peak chickenpox incidence in temperate zones occurs during winter and spring, when ultra-violet radiation is at its lowest. The evolution of geographically restricted genotypes is also explained by ultra-violet radiation driving natural selection of different virus genotypes with varying degrees of resistance to inactivation, tropical genotypes being the most resistant. Consequently, temperate viruses should be more sensitive to its effects. This is supported by the observation that temperate genotypes are found in the tropics only in specific circumstances, namely where ultra-violet radiation has either been excluded or significantly reduced in intensity. Testing the Hypothesis The hypothesis is testable by exposing

  15. Determination of the global daily radiation the value during the day; Determinacion de la irradiacion global diaria a partir de un minimo de valores de la irradiancia a lo largo del dia

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, M.; Fernandes, F.; Santos, J.; Prado, T.

    2004-07-01

    This paper is about the minimum number of solar irradiance values distributed along a day that lets to estimate the daily solar irradiation with an acceptable margin of error. The final objective of the study is to use the irradiance calculated from Meteosat images for obtaining solar radiation maps. The data base utilised is the radiance (minute radiation) and daily irradiation data base from the meteo-radiometric station of the University of Vigo Solar Lab for the years 2002 and 2003. Acceptable results are found with three values of the irradiance covering the six central hours of the day. In this case it is proposed a second order equation as the optimal regression adjustment. It is found also that it is not necessary to use more than five irradiance values covering the ten central hours of the day given that the optimal lineal regression adjustment is lineal, that is the proposed. (Author)

  16. Estimativa da produtividade de arroz irrigado em função da radiação solar global e da temperatura mínima do ar Rice yield estimates based on global solar radiation and minimum air temperature

    Directory of Open Access Journals (Sweden)

    Silvio Steinmetz

    2013-02-01

    Full Text Available Considerando-se a importância da produção do arroz irrigado no Estado do Rio Grande do Sul e que o seu desempenho é influenciado pelas condições meteorológicas, o objetivo deste trabalho foi estimar a produtividade de grãos dessa cultura em função da radiação solar global e da temperatura mínima do ar, usando procedimentos de análise de regressão linear simples e múltipla. Realizou-se um experimento de campo, em Capão do Leão, RS, durante três anos agrícolas. Empregaram-se, em cada ano agrícola, seis datas de semeadura e oito cultivares de diferentes grupos de comprimento de ciclo. Dez colmos principais de cada cultivar foram marcados, para determinarem-se os principais estádios de desenvolvimento. A variável dependente (Y foi a média da produtividade de quatro repetições, de cada época de semeadura, e as variáveis independentes foram: a média da radiação solar global (X¹, a média da temperatura mínima do ar (X² e a média da temperatura mínima do ar elevada ao quadrado (X³, computadas em quatro períodos de desenvolvimento da planta para a radiação solar global e em três períodos para a temperatura mínima do ar. A maioria das variáveis, quando testadas isoladamente, apresentou uma relação linear significativa com a produtividade, mas os coeficientes de determinação (r² foram mais elevados nas regressões lineares múltiplas envolvendo as principais variáveis. Modelos de regressão que utilizam como variáveis preditoras a radiação solar global e a temperatura mínima do ar, em diferentes períodos de desenvolvimento da planta, mostram-se adequados para a estimativa da produtividade de grãos de arroz irrigado.Considering the importance of irrigated rice production in the State of Rio Grande do Sul and that its performance is influenced by the weather conditions, the objective of this study was to estimate the grain yield of this crop as a function of global solar radiation and minimum air

  17. Retrieving air humidity, global solar radiation, and reference evapotranspiration from daily temperatures: development and validation of new methods for Mexico. Part III: reference evapotranspiration

    Science.gov (United States)

    Lobit, P.; Gómez Tagle, A.; Bautista, F.; Lhomme, J. P.

    2017-07-01

    We evaluated two methods to estimate evapotranspiration (ETo) from minimal weather records (daily maximum and minimum temperatures) in Mexico: a modified reduced set FAO-Penman-Monteith method (Allen et al. 1998, Rome, Italy) and the Hargreaves and Samani (Appl Eng Agric 1(2): 96-99, 1985) method. In the reduced set method, the FAO-Penman-Monteith equation was applied with vapor pressure and radiation estimated from temperature data using two new models (see first and second articles in this series): mean temperature as the average of maximum and minimum temperature corrected for a constant bias and constant wind speed. The Hargreaves-Samani method combines two empirical relationships: one between diurnal temperature range ΔT and shortwave radiation Rs, and another one between average temperature and the ratio ETo/Rs: both relationships were evaluated and calibrated for Mexico. After performing a sensitivity analysis to evaluate the impact of different approximations on the estimation of Rs and ETo, several model combinations were tested to predict ETo from daily maximum and minimum temperature alone. The quality of fit of these models was evaluated on 786 weather stations covering most of the territory of Mexico. The best method was found to be a combination of the FAO-Penman-Monteith reduced set equation with the new radiation estimation and vapor pressure model. As an alternative, a recalibration of the Hargreaves-Samani equation is proposed.

  18. Radiation Protection

    Science.gov (United States)

    ... EPA United States Environmental Protection Agency Search Search Radiation Protection Share Facebook Twitter Google+ Pinterest Contact Us Radiation Protection Document Library View and download EPA radiation ...

  19. Methane emissions from six crop species exposed to three components of global climate change: temperature, ultraviolet-B radiation and water stress.

    Science.gov (United States)

    Qaderi, Mirwais M; Reid, David M

    2009-10-01

    We examined the effects of temperature, ultraviolet-B (UVB) radiation and watering regime on aerobic methane (CH(4)) emission from six crops-faba bean, sunflower, pea, canola, barley and wheat. Plants were grown in controlled-environment growth chambers under two temperature regimes (24/20 and 30/26 degrees C), three levels of UVB radiation [0 (zero), 5 (ambient) and 10 (enhanced) kJ m(-2) d(-1)] and two watering regimes (well watered and water stressed). A gas chromatograph with a flame ionization detector was used to measure CH(4) emission rates [ng g(-1) dry weight (DW) h(-1)] from detached fresh leaves of each species and attached leaves of pea plants. Plant growth [stem height, leaf area (LA) and aboveground dry matter (AG biomass)] and gas exchange [net CO(2) assimilation (A(N)), transpiration (E) and water use efficiency (WUE)] were also determined. We found that higher temperature, water stress and UVB radiation at the zero and enhanced levels significantly enhanced CH(4) emissions. Crop species varied in CH(4) emission, which was highest for pea and lowest for barley. Higher temperature and water stress reduced all growth parameters, whereas ambient and enhanced UVB decreased stem height but increased LA and AG biomass. Higher temperature decreased A(N) and WUE but increased E, whereas water stress decreased A(N) but increased E and WUE. Zero and enhanced UVB reduced A(N) and E. Growth and gas exchange varied with species. Overall, CH(4) emission was negatively correlated with stem height and AG biomass. We conclude that CH(4) emissions may increase under climatic stress conditions and this extra source might contribute to the 'greenhouse effect'.

  20. Radiation Therapy

    Science.gov (United States)

    ... the area is stitched shut. Another treatment, called proton-beam radiation therapy , focuses the radiation on the ... after radiation treatment ends. Sore mouth and tooth decay. If you received radiation therapy to the head ...

  1. Radiation sickness

    Science.gov (United States)

    ... radiation. There are two basic types of radiation: ionizing and nonionizing. Nonionizing radiation comes in the form of light, radio waves, microwaves and radar. This kind of radiation usually ...

  2. Radiation dosimetry.

    OpenAIRE

    Cameron, J

    1991-01-01

    This article summarizes the basic facts about the measurement of ionizing radiation, usually referred to as radiation dosimetry. The article defines the common radiation quantities and units; gives typical levels of natural radiation and medical exposures; and describes the most important biological effects of radiation and the methods used to measure radiation. Finally, a proposal is made for a new radiation risk unit to make radiation risks more understandable to nonspecialists.

  3. Energy efficiency of photovoltaic modules mono and polycrystalline in function of global solar radiation; Eficiencia energetica de modulos fotovoltaicos mono e poli-cristalinos em funcao da radiacao solar global

    Energy Technology Data Exchange (ETDEWEB)

    Seraphim, Odivaldo Jose [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas. Dept. de Engenharia Rural], e-mail: seraphim@fca.unesp.br; Siqueira, Jair Antonio Cruz [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil). Centro de Ciencias Exatas e Tecnologicas], e-mail: jairsiqueira@fca.unesp.br; Silva, Carliane Diniz e [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil); Fiorentino, Jair de Jesus [Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Dept. de Engenharia Eletrica], e-mail: jairfiorentino@terra.com.br; Araujo, Joao Alberto Borges de [Faculdade de Tecnologia de Botucatu (FATEC), SP (Brazil). Dept. de Engenharia de Producao

    2004-07-01

    This research proposes a methodology to evaluate the acting of the solar energy conversion in electric energy, generated by photovoltaic modules installed under field conditions, constituted monocrystalline and polycrystalline silicon cells. The modules were appraised with relationship to energy efficiency for different marks and potency levels, in function of the readiness of solar radiation, being used loads sized for the nominal potency level of each module. The energy efficiency values calculated with the data obtained in field, didn't agree with the technical information presented by the makers of the modules monocrystalline, as being more efficient than the polycrystalline. Was ended, therefore, that the modules of the appraised marks presented inferior medium efficiency at 50% of the values supplied by the makers (author)

  4. Evaluation of solar radiation abundance and electricity production capacity for application and development of solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Rahim, Mustamin [Department of Architecture, Khairun University, Ternate (Indonesia); Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University (Japan); Yoshino, Jun; Yasuda, Takashi [Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University (Japan)

    2012-07-01

    This study was undertaken to analyze solar radiation abundance to ascertain the potential of solar energy as an electrical energy resource. Local weather forecasting for predicting solar radiation is performed using a meteorological model MM5. The prediction results are compared with observed results obtained from the Japan Meteorological Agency for verification of the data accuracy. Results show that local weather forecasting has high accuracy. Prediction of solar radiation is similar with observation results. Monthly average values of solar radiation are sufficiently good during March–September. Electrical energy generated by photovoltaic cells is almost proportional to the solar radiation amount. Effects of clouds on solar radiation can be removed by monthly averaging. The balance between supply and demand of electricity can be estimated using a standard curve obtained from the temporal average. When the amount of solar radiation every hour with average of more than 100 km radius area does not yield the standard curve, we can estimate the system of storage and auxiliary power necessary based on the evaluated results of imbalance between supply and demand.

  5. Global atmospheric change and herbivory: Effects of elevated levels of UV-B radiation, atmospheric CO{sub 2} and temperature on boreal woody plants and their herbivores

    Energy Technology Data Exchange (ETDEWEB)

    Veteli, T.

    2003-07-01

    The aim of this study was to assess the effects of elevated ultraviolet-B radiation (UV-B, 280- 320 nm), atmospheric CO{sub 2}, temperature and soil nitrogen level on the growth and chemical quality of boreal deciduous woody plants and on performance of the herbivorous insects feeding on them. Eggs and larvae of Operophtera brumata (L.) (Lepidoptera, Geometridae) were subjected to elevated UV-B radiation in the laboratory. Two willow species, Salix phylicifolia L. (Salicaceae) and S. myrsinifolia Salisb., were grown in an UV-B irradiation field where the responses of both plants and their herbivorous insects were monitored. S. myrsinifolia, Betula pendula Ehrh. (Betulaceae) and B. pubescens Roth. were subjected to elevated CO{sub 2} and temperature and different fertilisation levels in closed-top climatic chambers. To assess the indirect effects of the different treatments, the leaves of experimental willows and birches were fed to larvae of Phratora vitellinae (L.) (Coleoptera, Chrysomelidae) and adults of Agellastica alni L. in the laboratory. Elevated UV-B radiation significantly decreased the survival and performance of eggs and larvae of O. brumata. It also increased concentrations of some flavonoids and phenolic acids in S. myrsinifolia and S. phylicifolia, while the low-UV-B- absorbing phenolics, e. g. condensed tannins, gallic acid derivatives and salicylates, either decreased or remained unaffected. Both the height growth and biomass of one S. phylicifolia clone was sensitive to elevated levels of UV-B radiation. Abundance of adults and larvae of a willow- feeding leaf beetle, P. vitellinae, was increased under elevated UV-B; but this did not lead to increased leaf damage on the host plants. There were no significant differences in performance of the larvae feeding on differentially treated willow leaves, but adult A. alni preferred UV-B-treated leaves to ambient control leaves. Elevated CO{sub 2} and temperature significantly increased the height growth

  6. Reductions in Depth-integrated Picophytoplanktonic Photosynthesis Due to Inhibition by Ultraviolet and Photosynthetically Available Radiation: Global Predictions for $\\textit{Prochlorococcus}$ and $\\textit{Synechococcus}$

    CERN Document Server

    Neale, Patrick J

    2016-01-01

    Phytoplankton photosynthesis in most natural waters is often inhibited by ultraviolet (UV) and intense photosynthetically available radiation (PAR) but the effects on ocean productivity have received little consideration aside from polar areas subject to periodic enhanced UV-B due to depletion of stratospheric ozone. Here we consider responses in the temperate and tropical mid-ocean regions typically dominated by picophytoplankton including the prokaryotic lineages, $\\textit{Prochlorococcus}$ and $\\textit{Synechococcus}$. Spectral models of photosynthetic response for each lineage were constructed using model strains cultured at different growth irradiances and temperatures. In the model, inhibition becomes more severe once exposure exceeds a threshold (Emax) related to repair capacity. Model parameters are presented for $\\textit{Prochlorococcus}$ adding to those previously presented for $\\textit{Synechococcus}$. The models were applied to the estimation of mid-day, water-column photosynthesis based on an atm...

  7. Estimating photosynthetically available radiation at the ocean surface for primary production (3P Project): modeling, evaluation, and application to global MERIS imagery

    Science.gov (United States)

    Ramon, Didier; Jolivet, Dominique; Tan, Jing; Frouin, Robert

    2016-05-01

    The goal of the Photosynthetically available radiation (PAR) for Primary Production (3P) project is to provide robust, complete, and user-friendly satellite radiation products for ecosystem modeling, carbon cycle investigations, and climate change monitoring. A specific objective is to design and distribute a daily PAR product from MERIS and potentially the recent OLCI. In view of this, a PAR algorithm, based on the NASA Ocean Biology Processing Group (OBPG) operational algorithm, has been developed. The algorithm takes into account statistical diurnal variability of clouds using 3-hourly International Satellite Cloud Climatology (ISCCP) data. The PAR modeling, simplified to accommodate the information available, is evaluated using a Monte Carlo tool that simulates the satellite radiance and corresponding daily PAR. The daily PAR estimates obtained from reduced resolution (i.e., 1 km) MERIS data are evaluated against in situ measurements routinely collected from fixed buoys and platforms, namely BOUSSOLE in the Mediterranean Sea, CCE- 1 and -2 off the West coast of the United States, and COVE in the coastal Atlantic Ocean. The agreement between estimated and measured values is good on a daily time scale and substantially improved on a monthly time scale, with a bias of 2.7 (7.7%) E/m2/day and RMS errors of 8.5 (24.9%) and 4.5 (12.9%) E/m2/day. The bias is reduced significantly (by 1.8%) when using diurnal cloud climatology. Overestimation in cloudy conditions is partly explained by decoupling the clear atmosphere from the cloud/surface layer. Large gaps in regions affected by sun glint (not processed because incorrectly interpreted as cloudy) are adequately filled in the monthly PAR imagery. The statistical performance is satisfactory for long-term studies of aquatic primary production, especially in view of the much larger uncertainties on the fraction of PAR absorbed by live algae and the quantum yield of carbon fixation.

  8. Inflation of Molecular Clock Rates and Dates: Molecular Phylogenetics, Biogeography, and Diversification of a Global Cicada Radiation from Australasia (Hemiptera: Cicadidae: Cicadettini).

    Science.gov (United States)

    Marshall, David C; Hill, Kathy B R; Moulds, Max; Vanderpool, Dan; Cooley, John R; Mohagan, Alma B; Simon, Chris

    2016-01-01

    Dated phylogenetic trees are important for studying mechanisms of diversification, and molecular clocks are important tools for studies of organisms lacking good fossil records. However, studies have begun to identify problems in molecular clock dates caused by uncertainty of the modeled molecular substitution process. Here we explore Bayesian relaxed-clock molecular dating while studying the biogeography of ca. 200 species from the global cicada tribe Cicadettini. Because the available fossils are few and uninformative, we calibrate our trees in part with a cytochrome oxidase I (COI) clock prior encompassing a range of literature estimates for arthropods. We show that tribe-level analyses calibrated solely with the COI clock recover extremely old dates that conflict with published estimates for two well-studied New Zealand subclades within Cicadettini. Additional subclade analyses suggest that COI relaxed-clock rates and maximum-likelihood branch lengths become inflated relative to EF-1[Formula: see text] intron and exon rates and branch lengths as clade age increases. We present corrected estimates derived from: (i) an extrapolated EF-1[Formula: see text] exon clock derived from COI-calibrated analysis within the largest New Zealand subclade; (ii) post hoc scaling of the tribe-level chronogram using results from subclade analyses; and (iii) exploitation of a geological calibration point associated with New Caledonia. We caution that considerable uncertainty is generated due to dependence of substitution estimates on both the taxon sample and the choice of model, including gamma category number and the choice of empirical versus estimated base frequencies. Our results suggest that diversification of the tribe Cicadettini commenced in the early- to mid-Cenozoic and continued with the development of open, arid habitats in Australia and worldwide. We find that Cicadettini is a rare example of a global terrestrial animal group with an Australasian origin, with all non

  9. Global warming

    Science.gov (United States)

    Houghton, John

    2005-06-01

    'Global warming' is a phrase that refers to the effect on the climate of human activities, in particular the burning of fossil fuels (coal, oil and gas) and large-scale deforestation, which cause emissions to the atmosphere of large amounts of 'greenhouse gases', of which the most important is carbon dioxide. Such gases absorb infrared radiation emitted by the Earth's surface and act as blankets over the surface keeping it warmer than it would otherwise be. Associated with this warming are changes of climate. The basic science of the 'greenhouse effect' that leads to the warming is well understood. More detailed understanding relies on numerical models of the climate that integrate the basic dynamical and physical equations describing the complete climate system. Many of the likely characteristics of the resulting changes in climate (such as more frequent heat waves, increases in rainfall, increase in frequency and intensity of many extreme climate events) can be identified. Substantial uncertainties remain in knowledge of some of the feedbacks within the climate system (that affect the overall magnitude of change) and in much of the detail of likely regional change. Because of its negative impacts on human communities (including for instance substantial sea-level rise) and on ecosystems, global warming is the most important environmental problem the world faces. Adaptation to the inevitable impacts and mitigation to reduce their magnitude are both necessary. International action is being taken by the world's scientific and political communities. Because of the need for urgent action, the greatest challenge is to move rapidly to much increased energy efficiency and to non-fossil-fuel energy sources.

  10. Radiation Therapy

    Science.gov (United States)

    Radiation therapy is a cancer treatment. It uses high doses of radiation to kill cancer cells and stop them from ... half of all cancer patients receive it. The radiation may be external, from special machines, or internal, ...

  11. Radiation dosimetry

    CERN Document Server

    Hine, Gerald J; Hine, Gerald J

    1956-01-01

    Radiation Dosimetry focuses on the advancements, processes, technologies, techniques, and principles involved in radiation dosimetry, including counters and calibration and standardization techniques. The selection first offers information on radiation units and the theory of ionization dosimetry and interaction of radiation with matter. Topics include quantities derivable from roentgens, determination of dose in roentgens, ionization dosimetry of high-energy photons and corpuscular radiations, and heavy charged particles. The text then examines the biological and medical effects of radiation,

  12. Effects of DNA-targeted ionizing radiation produced by 5-[125I]iodo-2'-deoxyuridine on global gene expression in primary human cells

    Directory of Open Access Journals (Sweden)

    Panyutin Igor G

    2007-06-01

    differentially expressed transcripts reveal strikingly non-random chromosomal distribution in all the cell lines we used. Conclusion Our data suggest that DNA-targeted ionizing radiation produced by 125I-IUdR results in changes in expression of only a limited subset of genes in primary human cells. The responsive genes are distributed non-randomly among the chromosomes; and a significant fraction of them is p53-dependent in the transcriptional regulation.

  13. Thermodynamics of Radiation Modes

    Science.gov (United States)

    Pina, Eduardo; de la Selva, Sara Maria Teresa

    2010-01-01

    We study the equilibrium thermodynamics of the electromagnetic radiation in a cavity of a given volume and temperature. We found three levels of description, the thermodynamics of one mode, the thermodynamics of the distribution of frequencies in a band by summing over the frequencies in it and the global thermodynamics by summing over all the…

  14. Study of the OH and Cl-initiated oxidation, IR absorption cross-section, radiative forcing, and global warming potential of four C4-hydrofluoroethers.

    Science.gov (United States)

    Oyaro, Nathan; Sellevåg, Stig R; Nielsen, Claus J

    2004-11-01

    Infrared absorption cross-sections and OH and Cl reaction rate coefficients for four C4-hydrofluoroethers (CF3)2CHOCH3, CF3CH2OCH2CF3, CF3CF2CH2OCH3, and CHF2CF2CH2OCH3 are reported. Relative rate measurements at 298 K and 1013 hPa of OH and Cl reaction rate coefficients give k(OH+(CF3)2CHOCH3) = (1.27+/-0.13) x 10(-13), k(OH+CF3CH2OCH2CF3) = (1.51+/-0.24) x 10(-13), k(OH+CF3CF2CH2OCH3) = (6.42+/-0.33) x 10(-13), k(OH+CHF2CF2CH2OCH3) = (8.7 +/-0.5) x 10(-13), k(Cl+(CF3)2CHOCH3) = (8.4+/-1.3) x 10(-12), k(Cl+CF3CH2OCH2CF3) = (6.5+/-1.7) x 10(-13), k(Cl+CF3CF2CH2OCH3) = (4.0+/-0.8) x 10(-11), and k(Cl+CHF2CF2CH2OCH3) = (2.65+/-0.17) x 10(-11) cm3 molecule(-1) s(-1). The primary products of the OH and Cl reactions with the fluorinated ethers have been identified as esters, and OH and Cl reaction rate coefficients for one of these, CF3CH2OCHO, are reported: k(OH+CF3CH2OCHO) = (7.7+/-0.9) x 10(-14) and kCl+CF3CH2OCHO) = (6.3+/-1.9) x 10(-14) cm3 molecule(-1) s(-1) The rate coefficient for the Cl-atom reaction with CHF2CH2F is derived as k(Cl+CHF2CH2F) = (3.0+/-0.9) x 10(-14) cm3 molecule(-1) s(-1) at 298 K. The error limits include 3sigma from the statistical data analyses as well as the errors in the rate coefficients of the reference compounds employed. The tropospheric lifetimes of the hydrofluoroethers are estimated to be short tauOH((CF3)2CHOCH3) approximately 100 days, tauOH(CF3CH2OCH2CF3) approximately 80 days, tauOH(CF3CF2CH2OCH3) approximately 20 days, and tauOH(CHF2CF2CH2OCH3) approximately 14 days, and their global warming potentials are small compared to CFC-11.

  15. Radiation protection

    CERN Document Server

    CERN. Geneva

    2001-01-01

    This will be a simple explanation of the reasons why CERN has to be careful about radiation protections issues, a practical guide on how to recognize radiation dangers, the monitoring systems that make sure radiation levels are well tolerable norms, and a quick summary of what radiation levels mean in terms of personal risk.

  16. Globalization, Globalisation

    OpenAIRE

    Ethier, Wilfred J.

    2002-01-01

    This paper addresses a complex of globalization issues: the effect of globalization on the skill premium; the effect of globalization on unemployment; the relative importance of globalization and exogenous technical change; the effect of globalization on the ability of national governments to conduct independent social policies. Thinking about these topics has been dominated by a large empirical literature concluding that trade has played a relatively minor role in the rise of the skill premi...

  17. Against Globalization

    DEFF Research Database (Denmark)

    Philipsen, Lotte; Baggesgaard, Mads Anders

    2013-01-01

    In order to understand globalization, we need to consider what globalization is not. That is, in order to understand the mechanisms and elements that work toward globalization, we must, in a sense, read against globalization, highlighting the limitations of the concept and its inherent conflicts....... Only by employing this as a critical practice will we be analytically able to gain a dynamic understanding of the forces of globalization as they unfold today and as they have developed historically....

  18. Global warming without global mean precipitation increase?

    Science.gov (United States)

    Salzmann, Marc

    2016-06-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K(-1) decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge.

  19. Global Warming without Global Mean Precipitation Increase?

    Science.gov (United States)

    Salzmann, Marc

    2017-04-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large (3-4% per kelvin). This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7%K-1 decrease of the water vapor concentration with cooling from anthropogenic aerosol since the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean hydrological response to GHG warming has until recently been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHGs increases in the future, a clear signal will emerge.

  20. Using satellites to investigate the sensitivity of longwave downward radiation to water vapor at high elevations

    Science.gov (United States)

    Naud, Catherine M.; Miller, James R.; Landry, Chris

    2012-03-01

    Many studies suggest that high-elevation regions may be among the most sensitive to future climate change. However, in situ observations in these often remote locations are too sparse to determine the feedbacks responsible for enhanced warming rates. One of these feedbacks is associated with the sensitivity of longwave downward radiation (LDR) to changes in water vapor, with the sensitivity being particularly large in many high-elevation regions where the average water vapor is often low. We show that satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) can be used to expand the current ground-based observational database and that the monthly averaged clear-sky satellite estimates of humidity and LDR are in good agreement with the well-instrumented Center for Snow and Avalanche Studies ground-based site in the southwestern Colorado Rocky Mountains. The relationship between MODIS-retrieved precipitable water vapor and surface specific humidity across the contiguous United States was found to be similar to that previously found for the Alps. More important, we show that satellites capture the nonlinear relationship between LDR and water vapor and confirm that LDR is especially sensitive to changes in water vapor at high elevations in several midlatitude mountain ranges. Because the global population depends on adequate fresh water, much of which has its source in high mountains, it is critically important to understand how climate will change there. We demonstrate that satellites can be used to investigate these feedbacks in high-elevation regions where the coverage of surface-based observations is insufficient to do so.

  1. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P.; Koskela, T.; Damski, J.; Supperi, A. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1996-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  2. Global Strategy

    DEFF Research Database (Denmark)

    Li, Peter Ping

    2013-01-01

    Global strategy differs from domestic strategy in terms of content and process as well as context and structure. The content of global strategy can contain five key elements, while the process of global strategy can have six major stages. These are expounded below. Global strategy is influenced...... by rich and complementary local contexts with diverse resource pools and game rules at the national level to form a broad ecosystem at the global level. Further, global strategy dictates the interaction or balance between different entry strategies at the levels of internal and external networks....

  3. Radiation Therapy: Professions in Radiation Therapy

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Professions in Radiation Therapy Radiation Oncologist Therapeutic Medical Physicist Radiation Therapist Dosimetrist Radiation Oncology Nurse Social Worker Dietitian Radiation Oncologist Radiation oncologists are physicians who oversee the ...

  4. Global climate feedbacks

    Energy Technology Data Exchange (ETDEWEB)

    Manowitz, B.

    1990-10-01

    The important physical, chemical, and biological events that affect global climate change occur on a mesoscale -- requiring high spatial resolution for their analysis. The Department of Energy has formulated two major initiatives under the US Global Change Program: ARM (Atmospheric Radiation Measurements), and CHAMMP (Computer Hardware Advanced Mathematics and Model Physics). ARM is designed to use ground and air-craft based observations to document profiles of atmospheric composition, clouds, and radiative fluxes. With research and models of important physical processes, ARM will delineate the relationships between trace gases, aerosol and cloud structure, and radiative transfer in the atmosphere, and will improve the parameterization of global circulation models. The present GCMs do not model important feedbacks, including those from clouds, oceans, and land processes. The purpose of this workshop is to identify such potential feedbacks, to evaluate the uncertainties in the feedback processes (and, if possible, to parameterize the feedback processes so that they can be treated in a GCM), and to recommend research programs that will reduce the uncertainties in important feedback processes. Individual reports are processed separately for the data bases.

  5. Radiative heating in global climate models

    Energy Technology Data Exchange (ETDEWEB)

    Baer, F.; Arsky, N.; Rocque, K. [Univ. of Maryland, College Park, MD (United States)

    1996-04-01

    LWR algorithms from various GCMs vary significantly from one another for the same clear sky input data. This variability becomes pronounced when clouds are included. We demonstrate this effect by intercomparing the various models` output using observed data including clouds from ARM/CART data taken in Oklahoma.

  6. Globalization & technology

    DEFF Research Database (Denmark)

    Narula, Rajneesh

    Technology and globalization are interdependent processes. Globalization has a fundamental influence on the creation and diffusion of technology, which, in turn, affects the interdependence of firms and locations. This volume examines the international aspect of this interdependence at two levels...

  7. Global Health

    Science.gov (United States)

    ... globalhealth/what/default.htm) CDC protects Americans through global health. frame support disabled and/or not supported ... Public Health Emergencies More stories Infographic More infographics Global Health & You OUTBREAKS DISEASES & CONDITIONS TRAVEL CDC JOBS ...

  8. PEMANASAN GLOBAL

    Directory of Open Access Journals (Sweden)

    Vivi Triana

    2008-03-01

    Full Text Available Pemanasan global (global warming pada dasarnya merupakan fenomena peningkatan temperature global dari tahun ke tahun karena terjadinya efek rumah kaca (greenhouse effect yang disebabkan oleh meningkatnya emisi gas-gas seperti karbondioksida (CO2, metana (CH4, dinitrooksida (N2O dan CFC sehingga energy matahari terperangkap dalam atmosfer bumi. Berbagai literatur menunjukkan kenaikan temperatur global termasuk Indonesia yang terjadi pada kisaran 1,5 – 40 °C pada akhir abad 21.

  9. Alternative application for the radiation background in the development of the atlas database of atmospheric radiation

    CERN Document Server

    De la Hoz, Ivan Arturo Morales

    2014-01-01

    Nowadays radiation is one of the variables to be considered in the environmental forecasting and it is meaningful in the increase of global warming, together greenhouse effect. The radiation considered by the meteorological organizations depends on the World Radiometric Reference (WRR), the World Standard Group (WSG), addressed by the World Meteorological Organization (WMO). This work is based on the cosmic microwave background, as a variable to be estimated in order to get information about the incident radiation in the Earth's atmosphere, as a valuable and meaningful contribution in the building of the radiation atlas by the (UPME) and (IDEAM). Due to the fact that the variables considered are ultraviolet and infrared radiation, ozone column, direct radiation and diffuse radiation, the last two get the global radiation, and are the only ones to be evaluated by the national meteorological organizations in the country. The study of the cosmic background radiation as a research project will provide data which ...

  10. Global Education.

    Science.gov (United States)

    Longstreet, Wilma S., Ed.

    1988-01-01

    This issue contains an introduction ("The Promise and Perplexity of Globalism," by W. Longstreet) and seven articles dedicated to exploring the meaning of global education for today's schools. "Global Education: An Overview" (J. Becker) develops possible definitions, identifies objectives and skills, and addresses questions and…

  11. Global HRD.

    Science.gov (United States)

    1997

    This document contains four papers from a symposium on global human resource development (HRD). "Globalization of Human Resource Management (HRM) in Government: A Cross-Cultural Perspective" (Pan Suk Kim) relates HRM to national cultures and addresses its specific functional aspects with a unique dimension in a global organization.…

  12. Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations

    Science.gov (United States)

    Vergara-Temprado, Jesús; Murray, Benjamin J.; Wilson, Theodore W.; O'Sullivan, Daniel; Browse, Jo; Pringle, Kirsty J.; Ardon-Dryer, Karin; Bertram, Allan K.; Burrows, Susannah M.; Ceburnis, Darius; DeMott, Paul J.; Mason, Ryan H.; O'Dowd, Colin D.; Rinaldi, Matteo; Carslaw, Ken S.

    2017-03-01

    Ice-nucleating particles (INPs) are known to affect the amount of ice in mixed-phase clouds, thereby influencing many of their properties. The atmospheric INP concentration changes by orders of magnitude from terrestrial to marine environments, which typically contain much lower concentrations. Many modelling studies use parameterizations for heterogeneous ice nucleation and cloud ice processes that do not account for this difference because they were developed based on INP measurements made predominantly in terrestrial environments without considering the aerosol composition. Errors in the assumed INP concentration will influence the simulated amount of ice in mixed-phase clouds, leading to errors in top-of-atmosphere radiative flux and ultimately the climate sensitivity of the model. Here we develop a global model of INP concentrations relevant for mixed-phase clouds based on laboratory and field measurements of ice nucleation by K-feldspar (an ice-active component of desert dust) and marine organic aerosols (from sea spray). The simulated global distribution of INP concentrations based on these two species agrees much better with currently available ambient measurements than when INP concentrations are assumed to depend only on temperature or particle size. Underestimation of INP concentrations in some terrestrial locations may be due to the neglect of INPs from other terrestrial sources. Our model indicates that, on a monthly average basis, desert dusts dominate the contribution to the INP population over much of the world, but marine organics become increasingly important over remote oceans and they dominate over the Southern Ocean. However, day-to-day variability is important. Because desert dust aerosol tends to be sporadic, marine organic aerosols dominate the INP population on many days per month over much of the mid- and high-latitude Northern Hemisphere. This study advances our understanding of which aerosol species need to be included in order to

  13. Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Vergara-Temprado, Jesús; Murray, Benjamin J.; Wilson, Theodore W.; O& amp; apos; Sullivan, Daniel; Browse, Jo; Pringle, Kirsty J.; Ardon-Dryer, Karin; Bertram, Allan K.; Burrows, Susannah M.; Ceburnis, Darius; DeMott, Paul J.; Mason, Ryan H.; O& amp; apos; Dowd, Colin D.; Rinaldi, Matteo; Carslaw, Ken S.

    2017-01-01

    Ice-nucleating particles (INPs) are known to affect the amount of ice in mixed-phase clouds, thereby influencing many of their properties. The atmospheric INP concentration changes by orders of magnitude from terrestrial to marine environments, which typically contain much lower concentrations. Many modelling studies use parameterizations for heterogeneous ice nucleation and cloud ice processes that do not account for this difference because they were developed based on INP measurements made predominantly in terrestrial environments without considering the aerosol composition. Errors in the assumed INP concentration will influence the simulated amount of ice in mixed-phase clouds, leading to errors in top-of-atmosphere radiative flux and ultimately the climate sensitivity of the model. Here we develop a global model of INP concentrations relevant for mixed-phase clouds based on laboratory and field measurements of ice nucleation by K-feldspar (an ice-active component of desert dust) and marine organic aerosols (from sea spray). The simulated global distribution of INP concentrations based on these two species agrees much better with currently available ambient measurements than when INP concentrations are assumed to depend only on temperature or particle size. Underestimation of INP concentrations in some terrestrial locations may be due to the neglect of INPs from other terrestrial sources. Our model indicates that, on a monthly average basis, desert dusts dominate the contribution to the INP population over much of the world, but marine organics become increasingly important over remote oceans and they dominate over the Southern Ocean. However, day-to-day variability is important. Because desert dust aerosol tends to be sporadic, marine organic aerosols dominate the INP population on many days per month over much of the mid- and high-latitude Northern Hemisphere. This study advances our understanding of which aerosol species need to be included in order to

  14. Analysis of solar radiation variations over Nanjing region in recent 40 years%南京地区近40年来太阳辐射变化

    Institute of Scientific and Technical Information of China (English)

    张运林; 秦伯强; 陈伟民

    2003-01-01

    The data utilized in this analysis consisted of extraterrestrial radiation, global radiation,diffuse radiation, direct radiation, total cloud cover and relative sunshine. The annual variations andtrend were analyzed for monthly mean daily total global, direct, and diffuse radiation on a horizontalsurface and for the relations between global, direct, diffuse radiation and relative sunshine, total cloudcover. The climatological calculation equations of global and direct radiation are put forward. Theresults show that global and direct radiations are characterized by decrease and diffuse radiation byincrease. The main causes are due to the increase of concentration of suspended particles andatmospheric turbidifies rather than cloud cover variations.

  15. Global usability

    CERN Document Server

    Douglas, Ian

    2011-01-01

    The concept of usability has become an increasingly important consideration in the design of all kinds of technology. As more products are aimed at global markets and developed through internationally distributed teams, usability design needs to be addressed in global terms. Interest in usability as a design issue and specialist area of research and education has developed steadily in North America and Europe since the 1980's. However, it is only over the last ten years that it has emerged as a global concern. Global Usability provides an introduction to the important issues in globalizing des

  16. Protocol for Combined Analysis of FOXFIRE, SIRFLOX, and FOXFIRE-Global Randomized Phase III Trials of Chemotherapy +/- Selective Internal Radiation Therapy as First-Line Treatment for Patients With Metastatic Colorectal Cancer.

    Science.gov (United States)

    Virdee, Pradeep S; Moschandreas, Joanna; Gebski, Val; Love, Sharon B; Francis, E Anne; Wasan, Harpreet S; van Hazel, Guy; Gibbs, Peter; Sharma, Ricky A

    2017-03-28

    In colorectal cancer (CRC), unresectable liver metastases are associated with a poor prognosis. The FOXFIRE (an open-label randomized phase III trial of 5-fluorouracil, oxaliplatin, and folinic acid +/- interventional radioembolization as first-line treatment for patients with unresectable liver-only or liver-predominant metastatic colorectal cancer), SIRFLOX (randomized comparative study of FOLFOX6m plus SIR-Spheres microspheres versus FOLFOX6m alone as first-line treatment in patients with nonresectable liver metastases from primary colorectal carcinoma), and FOXFIRE-Global (assessment of overall survival of FOLFOX6m plus SIR-Spheres microspheres versus FOLFOX6m alone as first-line treatment in patients with nonresectable liver metastases from primary colorectal carcinoma in a randomized clinical study) clinical trials were designed to evaluate the efficacy and safety of combining first-line chemotherapy with selective internal radiation therapy (SIRT) using yttrium-90 resin microspheres, also called transarterial radioembolization. The aim of this analysis is to prospectively combine clinical data from 3 trials to allow adequate power to evaluate the impact of chemotherapy with SIRT on overall survival. Eligible patients are adults with histologically confirmed CRC and unequivocal evidence of liver metastases which are not treatable by surgical resection or local ablation with curative intent at the time of study entry. Patients may also have limited extrahepatic metastases. Final analysis will take place when all participants have been followed up for a minimum of 2 years. Efficacy and safety estimates derived using individual participant data (IPD) from SIRFLOX, FOXFIRE, and FOXFIRE-Global will be pooled using 2-stage prospective meta-analysis. Secondary outcome measures include progression-free survival (PFS), liver-specific PFS, health-related quality of life, response rate, resection rate, and adverse event profile. The large study population will

  17. Pelvic radiation - discharge

    Science.gov (United States)

    Radiation of the pelvis - discharge; Cancer treatment - pelvic radiation; Prostate cancer - pelvic radiation; Ovarian cancer - pelvic radiation; Cervical cancer - pelvic radiation; Uterine cancer - pelvic radiation; Rectal cancer - pelvic radiation

  18. 1961~2005年云贵高原太阳辐射变化特征及其影响因子%Variation Characteristics of Global Radiation and the Associated Climatic Factors over Yunnan- Guizhou Plateau in the Southwestern Part of China for 1961 - 2005

    Institute of Scientific and Technical Information of China (English)

    郑小波; 王学锋; 罗宇翔; 陈娟

    2011-01-01

    The variation characteristics of the global radiation and the meteorological factors such as cloud cover, humidity, wind speed, visibility, and sunshine duration which may impact the global radiation over the Yunnan -Guizhou Plateau in the southwestern part of China were studied by mathematical statistics method, with which thedata of nine radiation observation stations and about 200 weather stations from 1961 to 2005 were involved. The results show that the spatial distribution characteristics of annual global radiation are higher in the western part than the eastern part, and the highest is at Lijiang station (6207 MJ ? M-2 ? A-1), the lowest is at Zunyi station (3340 MJ ? M-2 ? A-1). The global radiations in six out of nine stations have no significant linear trend (P>0.1) in inter-annual variation, but the other three stations (Mengzi, Guiyang, and Zunyi) have a significant decline (P<0. 001) from the 1960s to the 1980s, and then followed by slight (Mengzi) or significant increasing (Guiyang). The main reason of the global radiation declining in Mengzi may owe to the visibility decreasing, and that in Guiyang is concerned with the increasing total cloud cover which result in sunshine duration decreasing. The cloud cover increasing and visibility decreasing are the reasons of the global radiation decline in Zunyi. Overall, interannual or decadal time scale variations of the global radiation are relative to the cloud cover and sunshine duration on the Yunnan - Guizhou Plateau during 1961 - 2005. The sunshine duration at city stations (Kunming and Guiyang) decreased with visibility reducing.%利用云贵高原1961~2005年9个日射站辐射和气候观测资料以及能见度观测资料等,采用数理统计方法,研究了该区域到达地表太阳总辐射量(以下简称总辐射)变化特征及其影响因子.结果表明:该区年总辐射的空间分布特点是西部高于东部,丽江站最高(6207MJ·m-2·a-1),遵义站最低(3340MJ·m-2·a-1).1961

  19. Two-dimensional monthly average ozone balance from limb infrared monitor of the stratosphere and stratospheric and mesospheric sounder data

    Science.gov (United States)

    Jackman, C. H.; Stolarski, R. S.; Kaye, J. A.

    1986-01-01

    For many years, atmospheric scientists have been concerned with the balance of ozone production and loss terms in the upper stratosphere. Crutzen and Schmailzl (1983) found that the ozone loss was higher than the ozone production in the upper stratosphere. In the present investigation, previous studies are used as a basis in the conduction of a two-dimensional calculation of the production and loss of ozone. The monthly and zonally averaged loss and production rates for ozone are computed using recent Nimbus 7 satellite measurements of stratospheric constituents and accepted reaction and photodissociation rates. It is found that ozone has a loss rate which is about 40-60 percent higher than the production in the photochemical region.

  20. ANALYSIS OF THE STATISTICAL BEHAVIOUR OF DAILY MAXIMUM AND MONTHLY AVERAGE RAINFALL ALONG WITH RAINY DAYS VARIATION IN SYLHET, BANGLADESH

    Directory of Open Access Journals (Sweden)

    G. M. J. HASAN

    2014-10-01

    Full Text Available Climate, one of the major controlling factors for well-being of the inhabitants in the world, has been changing in accordance with the natural forcing and manmade activities. Bangladesh, the most densely populated countries in the world is under threat due to climate change caused by excessive use or abuse of ecology and natural resources. This study checks the rainfall patterns and their associated changes in the north-eastern part of Bangladesh mainly Sylhet city through statistical analysis of daily rainfall data during the period of 1957 - 2006. It has been observed that a good correlation exists between the monthly mean and daily maximum rainfall. A linear regression analysis of the data is found to be significant for all the months. Some key statistical parameters like the mean values of Coefficient of Variability (CV, Relative Variability (RV and Percentage Inter-annual Variability (PIV have been studied and found to be at variance. Monthly, yearly and seasonal variation of rainy days also analysed to check for any significant changes.

  1. Moving toward climate-informed agricultural decision support - can we use PRISM data for more than just monthly averages?

    Science.gov (United States)

    Decision support systems/models for agriculture are varied in target application and complexity, ranging from simple worksheets to near real-time forecast systems requiring significant computational and manpower resources. Until recently, most such decision support systems have been constructed with...

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

    African Journals Online (AJOL)

    HOD

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

  3. Solar influences on global change

    Science.gov (United States)

    1994-01-01

    Monitoring of the Sun and the Earth has yielded new knowledge essential to this debate. There is now no doubt that the total radiative energy from the Sun that heats the Earth's surface changes over decadal time scales as a consequence of solar activity. Observations indicate as well that changes in ultraviolet radiation and energetic particles from the Sun, also connected with the solar activity, modulate the layer of ozone that protects the biosphere from the solar ultraviolet radiation. This report reassesses solar influences on global change in the light of this new knowledge of solar and atmospheric variability. Moreover, the report considers climate change to be encompassed within the broader concept of global change; thus the biosphere is recognized to be part of a larger, coupled Earth system. Implementing a program to continuously monitor solar irradiance over the next several decades will provide the opportunity to estimate solar influences on global change, assuming continued maintenance of observations of climate and other potential forcing mechanisms. In the lower atmosphere, an increase in solar radiation is expected to cause global warming. In the stratosphere, however, the two effects produce temperature changes of opposite sign. A monitoring program that would augment long term observations of tropospheric parameters with similar observations of stratospheric parameters could separate these diverse climate perturbations and perhaps isolate a greenhouse footprint of climate change. Monitoring global change in the troposphere is a key element of all facets of the United States Global Change Research Program (USGCRP), not just of the study of solar influences on global change. The need for monitoring the stratosphere is also important for global change research in its own right because of the stratospheric ozone layer.

  4. Atoms, Radiation, and Radiation Protection

    CERN Document Server

    Turner, James E

    2007-01-01

    Atoms, Radiation, and Radiation Protection offers professionals and advanced students a comprehensive coverage of the major concepts that underlie the origins and transport of ionizing radiation in matter. Understanding atomic structure and the physical mechanisms of radiation interactions is the foundation on which much of the current practice of radiological health protection is based. The work covers the detection and measurement of radiation and the statistical interpretation of the data. The procedures that are used to protect man and the environment from the potential harmful effects of

  5. Radiation Chemistry

    Science.gov (United States)

    Wojnárovits, L.

    Ionizing radiation causes chemical changes in the molecules of the interacting medium. The initial molecules change to new molecules, resulting in changes of the physical, chemical, and eventually biological properties of the material. For instance, water decomposes to its elements H2 and O2. In polymers, degradation and crosslinking take place. In biopolymers, e.g., DNS strand breaks and other alterations occur. Such changes are to be avoided in some cases (radiation protection), however, in other cases they are used for technological purposes (radiation processing). This chapter introduces radiation chemistry by discussing the sources of ionizing radiation (radionuclide sources, machine sources), absorption of radiation energy, techniques used in radiation chemistry research, and methods of absorbed energy (absorbed dose) measurements. Radiation chemistry of different classes of inorganic (water and aqueous solutions, inorganic solids, ionic liquids (ILs)) and organic substances (hydrocarbons, halogenated compounds, polymers, and biomolecules) is discussed in concise form together with theoretical and experimental backgrounds. An essential part of the chapter is the introduction of radiation processing technologies in the fields of polymer chemistry, food processing, and sterilization. The application of radiation chemistry to nuclear technology and to protection of environment (flue gas treatment, wastewater treatment) is also discussed.

  6. Radiation carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Fry, R.J.M.

    1976-01-01

    The risk of iatrogenic tumors with radiation therapy is so outweighed by the benefit of cure that estimates of risk have not been considered necessary. However, with the introduction of chemotherapy, combined therapy, and particle radiation therapy, the comparative risks should be examined. In the case of radiation, total dose, fractionation, dose rate, dose distribution, and radiation quality should be considered in the estimation of risk. The biological factors that must be considered include incidence of tumors, latent period, degree of malignancy, and multiplicity of tumors. The risk of radiation induction of tumors is influenced by the genotype, sex, and age of the patient, the tissues that will be exposed, and previous therapy. With chemotherapy the number of cells at risk is usually markedly higher than with radiation therapy. Clearly the problem of the estimation of comparative risks is complex. This paper presents the current views on the comparative risks and the importance of the various factors that influence the estimation of risk.

  7. Radiation acoustics

    CERN Document Server

    Lyamshev, Leonid M

    2004-01-01

    Radiation acoustics is a developing field lying at the intersection of acoustics, high-energy physics, nuclear physics, and condensed matter physics. Radiation Acoustics is among the first books to address this promising field of study, and the first to collect all of the most significant results achieved since research in this area began in earnest in the 1970s.The book begins by reviewing the data on elementary particles, absorption of penetrating radiation in a substance, and the mechanisms of acoustic radiation excitation. The next seven chapters present a theoretical treatment of thermoradiation sound generation in condensed media under the action of modulated penetrating radiation and radiation pulses. The author explores particular features of the acoustic fields of moving thermoradiation sound sources, sound excitation by single high-energy particles, and the efficiency and optimal conditions of thermoradiation sound generation. Experimental results follow the theoretical discussions, and these clearl...

  8. 24 - 27 BIT Corrected

    African Journals Online (AJOL)

    DR. AMIN

    MODELS FOR SUNSHINE HOURS OF KATSINA, NIGERIA. B. I. Tijjani ... been determined to estimate monthly average daily global solar radiation using sunshine hours for. Katsina (Lat ... The climate of Katsina is tropically continental and is.

  9. Hawking radiation

    Science.gov (United States)

    Parentani, Renaud; Spindel, Philippe

    2011-12-01

    Hawking radiation is the thermal radiation predicted to be spontaneously emitted by black holes. It arises from the steady conversion of quantum vacuum fluctuations into pairs of particles, one of which escaping at infinity while the other is trapped inside the black hole horizon. It is named after the physicist Stephen Hawking who derived its existence in 1974. This radiation reduces the mass of black holes and is therefore also known as black hole evaporation.

  10. Global Warming: Physics and Facts

    Energy Technology Data Exchange (ETDEWEB)

    Levi, B.G. [Physics Today, New York, NY (United States); Hafemeister, D. [Committee on Foreign Relations (U.S. Senate), Washington, DC (United States); Scribner, R. [Georgetown Univ., Washington, DC (United States)] [eds.

    1992-05-01

    This report contains papers on: A tutorial on global atmospheric energetics and the greenhouse effect; global climate models: what and how; comparison of general circulation models; climate and the earth`s radiation budget; temperature and sea level change; short-term climate variability and predictions; the great ocean conveyor; trace gases in the atmosphere: temporal and spatial trends; the geochemical carbon cycle and the uptake of fossil fuel CO{sub 2}; forestry and global warming; the physical and policy linkages; policy implications of greenhouse warming; options for lowering US carbon dioxide emissions; options for reducing carbon dioxide emissions; and science and diplomacy: a new partnership to protect the environment.

  11. Global Warming: Physics and Facts

    Energy Technology Data Exchange (ETDEWEB)

    Levi, B.G. (Physics Today, New York, NY (United States)); Hafemeister, D. (Committee on Foreign Relations (U.S. Senate), Washington, DC (United States)); Scribner, R. (Georgetown Univ., Washington, DC (United States)) (eds.)

    1992-01-01

    This report contains papers on: A tutorial on global atmospheric energetics and the greenhouse effect; global climate models: what and how; comparison of general circulation models; climate and the earth's radiation budget; temperature and sea level change; short-term climate variability and predictions; the great ocean conveyor; trace gases in the atmosphere: temporal and spatial trends; the geochemical carbon cycle and the uptake of fossil fuel CO{sub 2}; forestry and global warming; the physical and policy linkages; policy implications of greenhouse warming; options for lowering US carbon dioxide emissions; options for reducing carbon dioxide emissions; and science and diplomacy: a new partnership to protect the environment.

  12. Global fordeling

    DEFF Research Database (Denmark)

    Busck, Ole Gunni

    2015-01-01

    Øgede globale økologiske distributionskonflikter i kraft af neoliberal globalisering drevet af kravet om økonomisk vækst......Øgede globale økologiske distributionskonflikter i kraft af neoliberal globalisering drevet af kravet om økonomisk vækst...

  13. Global Uddannelse

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal

    Antologien handler om "demokratiproblemer i den globale sammenhæng" (del I) og "demokratiproblemer i uddannelse og for de offentligt ansatte" (del II), bundet sammen af et mellemstykke, der rækker ud mod begge poler både det globale og det lokale ved at knytte det til forholdet mellem marked...

  14. Gendering Globalization

    DEFF Research Database (Denmark)

    2009-01-01

    The current global financial situation bluntly and brutally brings home the fact that the global and local are closely connected in times of opportunity as well as crises. The articles in this issue of Asia Insights are about ontra-action between Asia, particularly China, and the Nordic countries...

  15. Solar shortwave radiation in the Iberian Peninsula along the last six decades

    Science.gov (United States)

    Bilbao, Julia; Román, Roberto; de Miguel, Argimiro; Pérez-Burgos, Ana

    2014-05-01

    The solar total shortwave radiation (SW, 305-2,800 nm) reaching the Earth surface is a key factor in the Earth energy balance and in the climate change. A decrease in SW levels has a cooling effect over the Earth. The SW changes are of interest in order to know the possible climatic effects. However long-term measured SW series are scarce, for example the oldest SW measurements in Spain are from 1973. The main objective of this work is to reconstruct and analyze nine long-term SW series from 1950 to 2011 in nine Spanish places located in the Iberian Peninsula. The data from different satellite retrievals were downloaded at the nine places: Total ozone column from different databases, spectral surface albedo and water vapour column from MODIS instrument, aerosol optical depth at 443 nm and Angström Exponent (between 443 nm and 670 nm) from MISR instrument onboard Terra satellite, and single scattering albedo from OMI instrument onboard Aura satellite. Moreover, sunshine duration records taken in the places were used. The UVSPEC/Libradtran radiative transfer model was run to obtain the daily SW irradiation under cloudless conditions in each location using as inputs monthly climatology tables calculated with the mentioned satellite retrievals. A model to obtain SW irradiation through the cloudless simulations and the sunshine records was developed, finding a great agreement with the monthly averaged SW measurements: a root mean square error of 5% and a mean bias error of 0.7%. The proposed model was used to obtain the daily SW irradiation, and the monthly, seasonal and annual averages, on the nine locations from 1950 to 2011. The homogeneity of these series was tested obtaining that all series are homogeneous. The anomalies of the series were calculated and a new series (Iberian Peninsula) of anomalies were obtained as an average of the nine locations. The annual SW on the Iberian Peninsula (the averaged series) shown a negative and statistically significant (99

  16. Global Mindsets

    DEFF Research Database (Denmark)

    Global Mindsets: Exploration and Perspectives seeks to tackle a topic that is relatively new in research and practice, and is considered by many to be critical for firms seeking to conduct global business. It argues that multiple mindsets exist (across and within organizations), that they operate...... it is important for future scholars and managers and how it could be conceptualized. Global Mindsets: Exploration and Perspectives is split into two major sections; the first examines where the literature currently is with respect to the knowledge in the field and what conceptual frameworks guide the thinking......, and should help researchers determine areas of high potential research needs in the future. Given the fluid sense of global mindsets in action, the authors of this book have adopted a flexible and wide-ranging approach. Global Mindsets: Exploration and Perspectives includes conceptual chapters that push...

  17. Global marketing and globalization miths

    OpenAIRE

    2012-01-01

    Global marketing and advertising: understanding cultural paradoxes, de Marieke de Mooij, 3rd ed. Thousand Oaks, CA. Sage Publications, 2010, 322p. Global marketing and advertising: understanding cultural paradoxes, de Marieke de Mooij, 3rd ed. Thousand Oaks, CA. Sage Publications, 2010, 322p.

  18. Global Content in Global Coursebooks

    Directory of Open Access Journals (Sweden)

    Mimoun Melliti

    2013-10-01

    Full Text Available This study aims at exploring the issue of “globality” in global coursebooks as manifested in investing features of connectedness, avoiding inappropriacy, and preserving inclusivity. To do this exploration, two research methods, content analysis and the questionnaire, were adopted. The content of an example of global coursebooks, Headway Intermediate (H/I, in addition to the perception of 251 of its users at Institute Bourguiba for Living Languages (IBLV were investigated. The results obtained revealed that “globality,” in terms of connectedness, inappropriacy, and inclusivity is partial in H/I as learners’ perceptions of it do not map with the content in the coursebook. This study raises questions about the suitability of global coursebooks to globally diverse learners and reveals the necessity of taking measures in the direction of localizing the content of English as a foreign language (EFL coursebooks.

  19. Global Rome

    DEFF Research Database (Denmark)

    Is 21st-century Rome a global city? Is it part of Europe's core or periphery? This volume examines the “real city” beyond Rome's historical center, exploring the diversity and challenges of life in neighborhoods affected by immigration, neoliberalism, formal urban planning, and grassroots social...... movements. The contributors engage with themes of contemporary urban studies–the global city, the self-made city, alternative modernities, capital cities and nations, urban change from below, and sustainability. Global Rome serves as a provocative introduction to the Eternal City and makes an original...

  20. Going Global

    DEFF Research Database (Denmark)

    Harrington, Brooke

    2015-01-01

    This study links theories of relationality and institutional change to deepen understanding of professionals’ role in globalization. In previous institutional research, it has been conventional to treat professionals as agents of firms or transnational organizations, and institutional change...... environment. It also broadens the model of agency to include invention and improvisation by individual professionals, as a counterpart to collective strategic action. The argument is based on data from a 16-nation study exploring the emergence of a particular ‘globalized localism’: the transformation...... to specify a new, more detailed model of the ways local practices and ideas develop into global institutions....

  1. Global Rome

    DEFF Research Database (Denmark)

    Is 21st-century Rome a global city? Is it part of Europe's core or periphery? This volume examines the “real city” beyond Rome's historical center, exploring the diversity and challenges of life in neighborhoods affected by immigration, neoliberalism, formal urban planning, and grassroots social...... movements. The contributors engage with themes of contemporary urban studies–the global city, the self-made city, alternative modernities, capital cities and nations, urban change from below, and sustainability. Global Rome serves as a provocative introduction to the Eternal City and makes an original...

  2. On quality control procedures for solar radiation and meteorological measures, from subhourly to montly average time periods

    Science.gov (United States)

    Espinar, B.; Blanc, P.; Wald, L.; Hoyer-Klick, C.; Schroedter-Homscheidt, M.; Wanderer, T.

    2012-04-01

    Meteorological data measured by ground stations are often a key element in the development and validation of methods exploiting satellite images. These data are considered as a reference against which satellite-derived estimates are compared. Long-term radiation and meteorological measurements are available from a large number of measuring stations. However, close examination of the data often reveals a lack of quality, often for extended periods of time. This lack of quality has been the reason, in many cases, of the rejection of large amount of available data. The quality data must be checked before their use in order to guarantee the inputs for the methods used in modelling, monitoring, forecast, etc. To control their quality, data should be submitted to several conditions or tests. After this checking, data that are not flagged by any of the test is released as a plausible data. In this work, it has been performed a bibliographical research of quality control tests for the common meteorological variables (ambient temperature, relative humidity and wind speed) and for the usual solar radiometrical variables (horizontal global and diffuse components of the solar radiation and the beam normal component). The different tests have been grouped according to the variable and the average time period (sub-hourly, hourly, daily and monthly averages). The quality test may be classified as follows: • Range checks: test that verify values are within a specific range. There are two types of range checks, those based on extrema and those based on rare observations. • Step check: test aimed at detecting unrealistic jumps or stagnation in the time series. • Consistency checks: test that verify the relationship between two or more time series. The gathered quality tests are applicable for all latitudes as they have not been optimized regionally nor seasonably with the aim of being generic. They have been applied to ground measurements in several geographic locations, what

  3. Global Mindset

    DEFF Research Database (Denmark)

    Sørensen, Olav Jull

    2016-01-01

    The concept of Global Mindset (GM) – the way to think about the global reality – is on the agenda of multinational companies concomitant with the increase in global complexity, uncertainty and diversity. In spite of a number of studies, the concept is still fluid and far from a managerial...... way of thinking about the global business reality. The other extreme is a GM as an organizational capability and process with a GM in a continuous state of becoming – and thus in a continuously alignment with a dynamic context. In addition, we argue for what we call “situational capabilities”, i.......e. the capability to sense (quickly), reflect (constructively) and act purposefully (for mutual benefit). A case on an MNC is used at the end to show the organizational manifestations of a GM....

  4. Global Derivatives

    DEFF Research Database (Denmark)

    Andersen, Torben Juul

    ." - Steen Parsholt, Chairman and CEO, Aon Nordic Region. "Andersen has done a wonderful job of developing a comprehensive text that deals with risk management in global markets. I would recommend this book to any student or businessman who has a need to better understand the risks and risk management...... management practice. Of particular note is the global and integrated approach chosen in this book which should be of special interest to aspiring managers active in global and international markets." - Dr Jean-Pierre Zigrand, Lecturer in Finance, London School of Economics, UK. More than 90 per cent...... management situations. Its key features include: derivatives are introduced in a global market perspective; describes major derivative pricing models for practical use, extending these principles to valuation of real options; practical applications of derivative instruments are richly illustrated...

  5. Global Managers

    DEFF Research Database (Denmark)

    Barakat, Livia L.; Lorenz, Melanie P.; Ramsey, Jase R.

    2016-01-01

    urpose: – The purpose of this paper is to examine the effect of cultural intelligence (CQ) on the job performance of global managers. Design/methodology/approach: – In total, 332 global managers were surveyed from multinational companies operating in Brazil. The mediating effect of job satisfaction...... was tested on the CQ-job performance relationship. Findings: – The findings suggest that job satisfaction transmits the effect of CQ to job performance, such that global managers high in CQ exhibit more job satisfaction in an international setting, and therefore perform better at their jobs. Practical...... implications: – Results imply that global managers should increase their CQ in order to improve their job satisfaction and ultimately perform better in an international context. Originality/value: – The authors make three primary contributions to the international business literature. First, the authors...

  6. Gendered Globalization

    DEFF Research Database (Denmark)

    Milwertz, Cecilia Nathansen; Cai, Yiping

    2017-01-01

    Both the People’s Republic of China (PRC) and Nordic countries (Sweden, Iceland, Denmark, Norway and Finland) view gender equality as a social justice issue and are politically committed towards achieving gender equality nationally and internationally. Since China has taken a proactive position o...... on globalization and global governance, gender equality is possibly an area that China may wish to explore in collaboration with the Nordic countries....

  7. Radiation Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Castor, J I

    2003-10-16

    The discipline of radiation hydrodynamics is the branch of hydrodynamics in which the moving fluid absorbs and emits electromagnetic radiation, and in so doing modifies its dynamical behavior. That is, the net gain or loss of energy by parcels of the fluid material through absorption or emission of radiation are sufficient to change the pressure of the material, and therefore change its motion; alternatively, the net momentum exchange between radiation and matter may alter the motion of the matter directly. Ignoring the radiation contributions to energy and momentum will give a wrong prediction of the hydrodynamic motion when the correct description is radiation hydrodynamics. Of course, there are circumstances when a large quantity of radiation is present, yet can be ignored without causing the model to be in error. This happens when radiation from an exterior source streams through the problem, but the latter is so transparent that the energy and momentum coupling is negligible. Everything we say about radiation hydrodynamics applies equally well to neutrinos and photons (apart from the Einstein relations, specific to bosons), but in almost every area of astrophysics neutrino hydrodynamics is ignored, simply because the systems are exceedingly transparent to neutrinos, even though the energy flux in neutrinos may be substantial. Another place where we can do ''radiation hydrodynamics'' without using any sophisticated theory is deep within stars or other bodies, where the material is so opaque to the radiation that the mean free path of photons is entirely negligible compared with the size of the system, the distance over which any fluid quantity varies, and so on. In this case we can suppose that the radiation is in equilibrium with the matter locally, and its energy, pressure and momentum can be lumped in with those of the rest of the fluid. That is, it is no more necessary to distinguish photons from atoms, nuclei and electrons, than it is

  8. Global Managers

    DEFF Research Database (Denmark)

    Barakat, Livia L.; Lorenz, Melanie P.; Ramsey, Jase R.

    2016-01-01

    Purpose: – The purpose of this paper is to examine the effect of cultural intelligence (CQ) on the job performance of global managers. Design/methodology/approach: – In total, 332 global managers were surveyed from multinational companies operating in Brazil. The mediating effect of job satisfact...... behavior literature, it is not often explicitly associated with global managers that are working in cross-cultural settings. Finally, the authors posit that job satisfaction mediates the relationship between CQ and job performance.......Purpose: – The purpose of this paper is to examine the effect of cultural intelligence (CQ) on the job performance of global managers. Design/methodology/approach: – In total, 332 global managers were surveyed from multinational companies operating in Brazil. The mediating effect of job...... satisfaction was tested on the CQ-job performance relationship. Findings: – The findings suggest that job satisfaction transmits the effect of CQ to job performance, such that global managers high in CQ exhibit more job satisfaction in an international setting, and therefore perform better at their jobs...

  9. Global warming

    CERN Document Server

    Hulme, M

    1998-01-01

    Global warming-like deforestation, the ozone hole and the loss of species- has become one of the late 20the century icons of global environmental damage. The threat, is not the reality, of such a global climate change has motivated governments. businesses and environmental organisations, to take serious action ot try and achieve serious control of the future climate. This culminated last December in Kyoto in the agreement for legally-binding climate protocol. In this series of three lectures I will provide a perspective on the phenomenon of global warming that accepts the scientific basis for our concern, but one that also recognises the dynamic interaction between climate and society that has always exited The future will be no different. The challenge of global warning is not to pretend it is not happening (as with some pressure groups), nor to pretend it threatens global civilisation (as with other pressure groups), and it is not even a challenge to try and stop it from happening-we are too far down the ro...

  10. Global Ocean Phytoplankton

    Science.gov (United States)

    Franz, B. A.; Behrenfeld, M. J.; Siegel, D. A.; Werdell, P. J.

    2014-01-01

    Marine phytoplankton are responsible for roughly half the net primary production (NPP) on Earth, fixing atmospheric CO2 into food that fuels global ocean ecosystems and drives the ocean's biogeochemical cycles. Phytoplankton growth is highly sensitive to variations in ocean physical properties, such as upper ocean stratification and light availability within this mixed layer. Satellite ocean color sensors, such as the Sea-viewing Wide Field-of-view Sensor (SeaWiFS; McClain 2009) and Moderate Resolution Imaging Spectroradiometer (MODIS; Esaias 1998), provide observations of sufficient frequency and geographic coverage to globally monitor physically-driven changes in phytoplankton distributions. In practice, ocean color sensors retrieve the spectral distribution of visible solar radiation reflected upward from beneath the ocean surface, which can then be related to changes in the photosynthetic phytoplankton pigment, chlorophyll- a (Chla; measured in mg m-3). Here, global Chla data for 2013 are evaluated within the context of the 16-year continuous record provided through the combined observations of SeaWiFS (1997-2010) and MODIS on Aqua (MODISA; 2002-present). Ocean color measurements from the recently launched Visible and Infrared Imaging Radiometer Suite (VIIRS; 2011-present) are also considered, but results suggest that the temporal calibration of the VIIRS sensor is not yet sufficiently stable for quantitative global change studies. All MODISA (version 2013.1), SeaWiFS (version 2010.0), and VIIRS (version 2013.1) data presented here were produced by NASA using consistent Chla algorithms.

  11. Amazonia and Global Change

    Science.gov (United States)

    Keller, Michael; Bustamante, Mercedes; Gash, John; Silva Dias, Pedro

    Amazonia and Global Change synthesizes results of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) for scientists and students of Earth system science and global environmental change. LBA, led by Brazil, asks how Amazonia currently functions in the global climate and biogeochemical systems and how the functioning of Amazonia will respond to the combined pressures of climate and land use change, such as • Wet season and dry season aerosol concentrations and their effects on diffuse radiation and photosynthesis • Increasing greenhouse gas concentration, deforestation, widespread biomass burning and changes in the Amazonian water cycle • Drought effects and simulated drought through rainfall exclusion experiments • The net flux of carbon between Amazonia and the atmosphere • Floodplains as an important regulator of the basin carbon balance including serving as a major source of methane to the troposphere • The impact of the likely increased profitability of cattle ranching. The book will serve a broad community of scientists and policy makers interested in global change and environmental issues with high-quality scientific syntheses accessible to nonspecialists in a wide community of social scientists, ecologists, atmospheric chemists, climatologists, and hydrologists.

  12. Diffuse solar radiation: measurement reliability

    Energy Technology Data Exchange (ETDEWEB)

    Butera, F.M.; Farruggia, S.; Festa, R.; Ratto, C.

    Numerous empirical relationships, found in literature, allow - where only the average monthly or daily value of global radiation on a horizontal surface is known - the determination of the components of both diffuse and direct radiations. These relationships result from the elaboration of data recorded mostly at weather stations located in North America. With the use of hourly data of global and diffuse solar radiation, recorded in Genova, Italy, during a period of six years, it is shown that the above mentioned relationships give values which systematically differ from experimental ones, even if some offer better results than others. Furthermore, the extent of the difference and the similar results obtained from other researchers indicate the possibility of specific weather conditions in the Mediterranean area.

  13. Radiation Exposure

    Science.gov (United States)

    ... on to any children you have after the exposure. A lot of radiation over a short period, ... skin burns and reduced organ function. If the exposure is large enough, it can cause premature aging ...

  14. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

    a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

  15. Aerosol properties and associated radiative effects over Cairo (Egypt)

    Science.gov (United States)

    El-Metwally, M.; Alfaro, S. C.; Wahab, M. M. Abdel; Favez, O.; Mohamed, Z.; Chatenet, B.

    2011-02-01

    Cairo is one of the largest megacities in the World and the particle load of its atmosphere is known to be particularly important. In this work we aim at assessing the temporal variability of the aerosol's characteristics and the magnitude of its impacts on the transfer of solar radiation. For this we use the level 2 quality assured products obtained by inversion of the instantaneous AERONET sunphotometer measurements performed in Cairo during the Cairo Aerosol CHaracterization Experiment (CACHE), which lasted from the end of October 2004 to the end of March 2006. The analysis of the temporal variation of the aerosol's optical depth (AOD) and spectral dependence suggests that the aerosol is generally a mixture of at least 3 main components differing in composition and size. This is confirmed by the detailed analysis of the monthly-averaged size distributions and associated optical properties (single scattering albedo and asymmetry parameter). The components of the aerosol are found to be 1) a highly absorbing background aerosol produced by daily activities (traffic, industry), 2) an additional, 'pollution' component produced by the burning of agricultural wastes in the Nile delta, and 3) a coarse desert dust component. In July, an enhancement of the accumulation mode is observed due to the atmospheric stability favoring its building up and possibly to secondary aerosols being produced by active photochemistry. More generally, the time variability of the aerosol's characteristics is due to the combined effects of meteorological factors and seasonal production processes. Because of the large values of the AOD achieved during the desert dust and biomass burning episodes, the instantaneous aerosol radiative forcing (RF) at both the top (TOA) and bottom (BOA) of the atmosphere is maximal during these events. For instance, during the desert dust storm of April 8, 2005 RF BOA, RF TOA, and the corresponding atmospheric heating rate peaked at - 161.7 W/m 2, - 65.8 W/m 2

  16. Radiation Transport

    Energy Technology Data Exchange (ETDEWEB)

    Urbatsch, Todd James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  17. Radiation Protection

    Energy Technology Data Exchange (ETDEWEB)

    Loos, M

    2001-04-01

    Major achievements of SCK-CEN's Radiation Protection Department in 2000 are described. The main areas for R and D of the department remain neutron dosimetry and neutron activation analysis, safeguards information handling and non-destructive assay techniques. Further activities include low-level radioactivity measurements in environmental and biological samples and radiation protection research. Finally, achievements in decision strategy research and social sciences in nuclear research are reported.

  18. Live with radiation from the basics to practice. Proceedings; Leben mit Strahlung - Von den Grundlagen zur Praxis. Tagungsbeitraege

    Energy Technology Data Exchange (ETDEWEB)

    Maringer, Franz Josef; Czarwinski, Renate; Geringer, Thomas; Brandl, Alexander; Steurer, Andreas (eds.)

    2009-07-01

    The conference proceedings of the common radiation protection meeting 2009 in Alpbach, Tyrol include29 papers concerning global safety, 33 papers concerning environment, 18 papers concerning radiation protection in medicine, and 16 papers concerning live with radiation.

  19. Synchrotron radiation with radiation reaction

    Science.gov (United States)

    Nelson, Robert W.; Wasserman, Ira

    1991-04-01

    A rigorous discussion is presented of the classical motion of a relativistic electron in a magnetic field and the resulting electromagnetic radiation when radiation reaction is important. In particular, for an electron injected with initial energy gamma(0), a systematic perturbative solution to the Lorentz-Dirac equation of motion is developed for field strengths satisfying gamma(0) B much less than 6 x 10 to the 15th G. A particularly accurate solution to the electron orbital motion in this regime is found and it is demonstrated how lowest-order corrections can be calculated. It is shown that the total energy-loss rate corresponds to what would be found using the exact Larmor power formula without including radiation reaction. Provided that the particle energy and field strength satisfy the same contraint, it is explicitly demonstrated that the intuitive prescription for calculating the time-integrated radiation spectrum described above is correct.

  20. Global Programs

    Science.gov (United States)

    Lindberg Christensen, Lars; Russo, P.

    2009-05-01

    IYA2009 is a global collaboration between almost 140 nations and more than 50 international organisations sharing the same vision. Besides the common brand, mission, vision and goals, IAU established eleven cornerstones programmes to support the different IYA2009 stakeholder to organize events, activities under a common umbrella. These are global activities centred on specific themes and are aligned with IYA2009's main goals. Whether it is the support and promotion of women in astronomy, the preservation of dark-sky sites around the world or educating and explaining the workings of the Universe to millions, the eleven Cornerstones are key elements in the success of IYA2009. However, the process of implementing global projects across cultural boundaries is challenging and needs central coordination to preserve the pre-established goals. During this talk we will examine the ups and downs of coordinating such a project and present an overview of the principal achievements for the Cornerstones so far.

  1. Global Inequality

    DEFF Research Database (Denmark)

    Niño-Zarazúa, Miguel; Roope, Laurence; Tarp, Finn

    2016-01-01

    This paper measures trends in global interpersonal inequality during 1975–2010 using data from the most recent version of the World Income Inequality Database (WIID). The picture that emerges using ‘absolute,’ and even ‘centrist’ measures of inequality, is very different from the results obtained...... using standard ‘relative’ inequality measures such as the Gini coefficient or Coefficient of Variation. Relative global inequality has declined substantially over the decades. In contrast, ‘absolute’ inequality, as captured by the Standard Deviation and Absolute Gini, has increased considerably...... and unabated. Like these ‘absolute’ measures, our ‘centrist’ inequality indicators, the Krtscha measure and an intermediate Gini, also register a pronounced increase in global inequality, albeit, in the case of the latter, with a decline during 2005 to 2010. A critical question posed by our findings is whether...

  2. Abdominal radiation - discharge

    Science.gov (United States)

    Radiation - abdomen - discharge; Cancer - abdominal radiation; Lymphoma - abdominal radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after radiation treatment starts, you might notice changes ...

  3. Brain radiation - discharge

    Science.gov (United States)

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  4. Another globalization

    Directory of Open Access Journals (Sweden)

    Prof. Ph.D. Ion Bucur

    2007-05-01

    Full Text Available Finding the anachronisms and the failures of the present globalization, as well as the vitiated system of world-wide government, has stimulated the debates regarding the identification of a more equitable form of globalization to favor the acceleration of the economic increase and the reduction of poverty.The deficiency of the present international economic institutions, especially the lack of transparency and democratic responsibility, claims back with acuteness the reformation of the architecture of the international institutional system and the promotion of those economical policies which must ensure the stability world-wide economy and the amelioration of the international equity.

  5. Conceived globals

    DEFF Research Database (Denmark)

    Cheraghi, Maryam; Schøtt, Thomas

    2016-01-01

    A firm may be conceived global, in the sense that, before its birth, the founding entrepreneur has a transnational network of advisors which provides an embedding for organising the upstart that may include assembling resources and marketing abroad. The purpose is to account for the entrepreneurs...... the intending, starting and operating phases, fairly constantly with only small fluctuations. The firm is conceived global in terms of the entrepreneur's transnational networking already in the pre-birth phase, when the entrepreneur is intending to start the firm. These phase effects hardly depend on attributes...

  6. Going global?

    DEFF Research Database (Denmark)

    Fejerskov, Adam Moe; Rasmussen, Christel

    2016-01-01

    During the past decade, academic attention to the role of private foundations in international development cooperation has greatly intensified. The largest foundations have increased their global giving and moved towards strategic social impact, but we do not know if such processes have also...... occurred at a more micro level. This article explores this issue by studying the international activities of Danish foundations. It finds that grant-making on global issues is increasing, and that several foundations have undergone transformations in their approach to grantmaking, making them surprisingly...

  7. Ethical issues in radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Lars (ed.)

    2000-03-15

    Ethical theories are relevant to the current recommendations and standards for radiation protection. Radiation protection is not only a matter for science. It is also a problem of philosophy. In order for protection regulations to be respected, it must correspond to widely accepted ethical values among those who are affected by the regulations. The workshop covered the following issues: Problems in Present Protection Policy, ICRP Protection Policy - A Historical Perspective, Radiation Risk - What we know and what we believe, Present ICRP Recommendations, Ethical Values in the Context of ICRP Recommendations, Collective Responsibility for Invisible Harm, Environmental Protection - Ethical Issues, The Global Change of Values, and Procedural justice and Radiation Protection. Six workshop contributions and a workshop summary are presented in this report.

  8. Speaking globally

    NARCIS (Netherlands)

    van der Linden, M.

    2009-01-01

    The recent growth of the working classes in various parts of the Global South (or what was called the Tricontinent of Africa, Asia, and Latin America some years ago) has important consequences for labor historians. For a very long time labor history was mainly based in the North Atlantic region,

  9. Global Sourcing

    NARCIS (Netherlands)

    M.J. Mol; R.J.M. van Tulder (Rob); P.R. Beije (Paul)

    2002-01-01

    textabstractSince the early 1990s international - or even global - outsourcing of intermediate products from suppliers has been propagated as a key means to improve the performance of firms. It is argued that becoming more lean and internationally focused is beneficial for the buyer as

  10. Global glance

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Molycorp Announces Successful Close of Neo Materials Acquisition Molycorp, Inc. announced on 11 June 2012 that its acquisition of Canadian-based Neo Material Technologies Inc. has officially closed, creating a global rare earth leader with a combination of a world-class rare earth resource, ultra-high-purity rare earth processing capabilities, and full 'mine-to-magnetics' vertical integration.

  11. Justice Globalism

    NARCIS (Netherlands)

    Wilson, Erin; Steger, Manfred; Siracusa, Joseph; Battersby, Paul

    2014-01-01

    The pursuit of a global order founded on universal rules extends beyond economics into the normative spheres of law, politics and justice. Justice globalists claim universal principles applicable to all societies irrespective of religion or ideology. This view privileges human rights, democracy and

  12. Global overeksponering

    DEFF Research Database (Denmark)

    Rosenstand, Claus A. Foss

    2007-01-01

    - idet min lillebror er blandt de anholdte; og mine forældre derfor skulle være blandt de skyldige. Hvilket har fået mig til at fare i blækhuset, med en alternativ forklaringsmodel, der ikke handler om skyld. Kulturen omkring Ungdomshuset er globalt orienteret, og derfor meget sensible overfor global...... forandringer. Den globale orientering kommer blandt andet til udtryk i det relativt store internationale netværk, som bakker de unge op i deres protester - enten ved tilstedeværelse i København eller andre sympatiaktioner. Siden den 11. september, 2001, er globale realiteter blevet eksponeret i massemedierne...... også sig selv og sin omverden igennem en global optik. Ungdommen af i dag er som børn vokset op i et samfund og dannelseskultur, der ikke har været globalt orienteret, hvor demokratiske værdier som frihed, lighed, menneskerettigheder her hersket i det socialdemokratiske projekt om sammenhængskraft. Og...

  13. Global Games

    NARCIS (Netherlands)

    van Bottenburg, Maarten

    2001-01-01

    Why is soccer the sport of choice in South America, while baseball has soared to popularity in the Carribean? How did cricket become India's national sport, while China is a stronghold of table tennis? In Global Games, Maarten van Bottenburg asserts that it is the 'hidden competition' of social and

  14. Justice Globalism

    NARCIS (Netherlands)

    Wilson, Erin; Steger, Manfred; Siracusa, Joseph; Battersby, Paul

    2014-01-01

    The pursuit of a global order founded on universal rules extends beyond economics into the normative spheres of law, politics and justice. Justice globalists claim universal principles applicable to all societies irrespective of religion or ideology. This view privileges human rights, democracy and

  15. Globalizing America

    DEFF Research Database (Denmark)

    Brewer, Thomas L.; Boyd, Gavin

    An argument that globalization is an ungoverned integration process in which US firms are agents of structural change. It describes the benefits and costs (for example, generating pressure for protection of US home markets), and reviews the expansion of interdependencies between the US and others....

  16. Global overeksponering

    DEFF Research Database (Denmark)

    Rosenstand, Claus A. Foss

    2007-01-01

    - idet min lillebror er blandt de anholdte; og mine forældre derfor skulle være blandt de skyldige. Hvilket har fået mig til at fare i blækhuset, med en alternativ forklaringsmodel, der ikke handler om skyld. Kulturen omkring Ungdomshuset er globalt orienteret, og derfor meget sensible overfor global...... forandringer. Den globale orientering kommer blandt andet til udtryk i det relativt store internationale netværk, som bakker de unge op i deres protester - enten ved tilstedeværelse i København eller andre sympatiaktioner. Siden den 11. september, 2001, er globale realiteter blevet eksponeret i massemedierne...... også sig selv og sin omverden igennem en global optik. Ungdommen af i dag er som børn vokset op i et samfund og dannelseskultur, der ikke har været globalt orienteret, hvor demokratiske værdier som frihed, lighed, menneskerettigheder her hersket i det socialdemokratiske projekt om sammenhængskraft. Og...

  17. Global militarization

    Energy Technology Data Exchange (ETDEWEB)

    Wallensteen, P.; Galtung, J.; Portales, C.

    1985-01-01

    This book contains 10 chapters. Some of the titles are: Military Formations and Social Formations: A Structural Analysis; Global Conflict Formations: Present Developments and Future Directions; War and the Power of Warmakers in Western Europe and Elsewhere, 1600-1980; and The Urban Type of Society and International War.

  18. Global Games

    NARCIS (Netherlands)

    van Bottenburg, Maarten

    2001-01-01

    Why is soccer the sport of choice in South America, while baseball has soared to popularity in the Carribean? How did cricket become India's national sport, while China is a stronghold of table tennis? In Global Games, Maarten van Bottenburg asserts that it is the 'hidden competition' of social and

  19. Analysis of solar radiation variations over Nanjing region in recent 40 years

    Institute of Scientific and Technical Information of China (English)

    ZHANGYunlin; QINBoqiang; CHENWeimin

    2003-01-01

    The data utilized in this analysis consisted of extraterrestrial radiation,global radiation,diffuse radiation,total cloud cover and relative sunshine.The annual variations and trend were analyzed for monthly mean daily total global,direct,and diffuse radiation on a horizontal surface and for the relations between global,direct,diffuse radiation and relative sunshine,total cloud cover.The climatlolgical calculation equations of global and direct radiation are put forward.The results show that global and direct radiations are characterized by decrease and diffuse radiation by increase.The main causes are due to the increase of concentration of suspended particles and atmospheric turbidities rather than cloud cover variations.

  20. Directional radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, Jonathan L.

    2017-09-12

    Directional radiation detectors and systems, methods, and computer-readable media for using directional radiation detectors to locate a radiation source are provided herein. A directional radiation detector includes a radiation sensor. A radiation attenuator partially surrounds the radiation sensor and defines an aperture through which incident radiation is received by the radiation sensor. The aperture is positioned such that when incident radiation is received directly through the aperture and by the radiation sensor, a source of the incident radiation is located within a solid angle defined by the aperture. The radiation sensor senses at least one of alpha particles, beta particles, gamma particles, or neutrons.

  1. Estimation of hourly clear-sky solar radiation for P. D. R. Yemen

    Energy Technology Data Exchange (ETDEWEB)

    Abdul Aziz, G.M. (Aden Univ., (P.D.R. Yemen) Faculty of Engineering)

    1990-01-01

    Monthly average hourly clear sky solar radiation for some principal stations in P.D.R. Yemen are evaluated. Hottel's model is used to predict the hourly clear sky beam and horizontal solar radiation and that of Liu and Jordan for the estimation of clear sky diffuse radiation. The two methods are combined to obtain the clear sky total radiation. Maximum and minimum clear sky total solar radiation are evaluated. The maxima are situated between 21.0 MJ/m{sup 2} and 26.6 MJ/m{sup 2}, minima between 15.0 MJ/m{sup 2} and 19.1 MJ/m{sup 2} for Aden and Mukairas respectively. Mean hourly clear-sky solar radiation are computed and discussed. 75% of the estimated radiation on a horizontal surface is obtained between 9 a.m.-3 p.m. The average intensity is about 700 W.m{sup 2} for Aden and 900 W/m{sup 2} for Mukairas. (author).

  2. Cherenkov radiation; La radiation Cerenkov

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    When the radioactivity has been discovered, it was observed by researchers that different materials as mineral salts or solutions were emitting a weak light when submitted to radioactivity beams. At the beginning it has been thought that it was fluorescent light. In 1934, Cherenkov, a russian physicist, worked on the luminescence of uranyl salts solutions caused by gamma radiation and observed a very weak light was emitted by pure liquid. After further studies, he concluded that this phenomena was different from fluorescence. Since then, it has been called Cherenkov effect. This blue light emission is produced when charged particles are going through a transparent medium with an upper velocity than light velocity. This can happen only in medium with large refractive index as water or glass. It also presents its different properties discovered afterwards. The different applications of the Cherenkov radiation are discussed as counting techniques for radiation detectors or comic ray detectors. (M.P.)

  3. Aerosol absorption and radiative forcing

    Directory of Open Access Journals (Sweden)

    P. Stier

    2007-05-01

    Full Text Available We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006 significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA radiative forcing clear-sky from –0.79 to –0.53 W m−2 (33% and all-sky from –0.47 to –0.13 W m−2 (72%. Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36% clear-sky and of 0.12 W m−2 (92% all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W

  4. Radiation Technology Against Bioterrorism

    Science.gov (United States)

    2004-10-25

    application of radiation processing: radiation crosslinking of polymers and radiation sterilization of health care products have developed into substantial...municipal waste water, • radiation inactivation of bioterrorism agents, • electron beam processing of flue gases, • radiation crosslinking , • radiation...Electron beam processing of flue gases 6. Radiation crosslinking 7. Radiation curing 3 Radiation Technology Against Bioterrorism L.G. Gazsó and G

  5. Global warming and greenhouse gases

    OpenAIRE

    Belić Dragoljub S.

    2006-01-01

    Global warming or Climate change refers to long-term fluctuations in temperature, precipitation, wind, and other elements of the Earth's climate system. Natural processes such as solar-irradiance variations, variations in the Earth's orbital parameters, and volcanic activity can produce variations in climate. The climate system can also be influenced by changes in the concentration of various gases in the atmosphere, which affect the Earth's absorption of radiation.

  6. Global Europa

    DEFF Research Database (Denmark)

    Manners, Ian

    2010-01-01

    The mythology of the European Union (EU) in world politics can be told and untold in many different ways. This article focuses on the lore or stories of who did what to whom, the ideological projection of the past onto the present and the escapist pleasure of story telling in looking at the mytho......The mythology of the European Union (EU) in world politics can be told and untold in many different ways. This article focuses on the lore or stories of who did what to whom, the ideological projection of the past onto the present and the escapist pleasure of story telling in looking...... at the mythology of ‘global Europa' - the EU in the world. It concludes with a reflection on the way in which the many diverse myths of global Europa compete for daily attention, whether as lore, ideology, or pleasure. In this respect the mythology of global Europa is part of our everyday existence, part of the EU...

  7. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  8. Projections of UV radiation changes in the 21st century: impact of ozone recovery and cloud effects

    Directory of Open Access Journals (Sweden)

    A. F. Bais

    2011-08-01

    Full Text Available Monthly averaged surface erythemal solar irradiance (UV-Ery for local noon from 1960 to 2100 has been derived using radiative transfer calculations and projections of ozone, temperature and cloud change from 14 chemistry climate models (CCM, as part of the CCMVal-2 activity of SPARC. Our calculations show the influence of ozone depletion and recovery on erythemal irradiance. In addition, we investigate UV-Ery changes caused by climate change due to increasing greenhouse gas concentrations. The latter include effects of both stratospheric ozone and cloud changes. The derived estimates provide a global picture of the likely changes in erythemal irradiance during the 21st century. Uncertainties arise from the assumed scenarios, different parameterizations – particularly of cloud effects on UV-Ery – and the spread in the CCM projections. The calculations suggest that relative to 1980, annually mean UV-Ery in the 2090s will be on average ~12 % lower at high latitudes in both hemispheres, ~3 % lower at mid latitudes, and marginally higher (~1 % in the tropics. The largest reduction (~16 % is projected for Antarctica in October. Cloud effects are responsible for 2–3 % of the reduction in UV-Ery at high latitudes, but they slightly moderate it at mid-latitudes (~1 %. The year of return of erythemal irradiance to values of certain milestones (1965 and 1980 depends largely on the return of column ozone to the corresponding levels and is associated with large uncertainties mainly due to the spread of the model projections. The inclusion of cloud effects in the calculations has only a small effect of the return years. At mid and high latitudes, changes in clouds and stratospheric ozone transport by global circulation changes due to greenhouse gases will sustain the erythemal irradiance at levels below those in 1965, despite the removal of ozone depleting substances. At northern high latitudes (60°–90°, the projected decreases in cloud

  9. Global Noise and Global Englishes

    Directory of Open Access Journals (Sweden)

    Alastair Pennycook

    2013-09-01

    Full Text Available Global Noise: Rap and Hip-Hop Outside the USA, alluding to Tricia Rose’s US rap-music book, Black Noise, aims to do much more than merely extend the reach of the study of rap and hip-hop beyond the USA, as its subtitle might suggest. While acknowledging the importance of the work of both Rose and Potter, this collection’s editor, Tony Mitchell, contests their respective views that rap and hip-hop are essentially expressions of African-American culture, and that all forms of rap and hip-hop derive from these origins. He argues that these forms have become ‘a vehicle for global youth affiliations and a tool for reworking local iden- tity all over the world’.

  10. Global climate experiment; Globales Klimaexperiment

    Energy Technology Data Exchange (ETDEWEB)

    Quasching, V. [Deutsche Zentrum fuer Luft- und Raumfahrt e.V., Plataforma Solar de Almeria (Spain)

    2003-07-01

    Continued greenhouse gas emissions are part of one of our today's largest scientific experiments. Most scientists agree that anthropogenic influences are responsible for already observed climatic changes. Others demand further investigations and justify continued unlimited use of fossil energy sources. This paper describes generally accepted facts on greenhouse gas emissions and climatic change with focus on part and influence of the global energy industry. [German] Mit dem fortgesetzten Ausstoss von Treibhausgasen wird zurzeit ein globales naturwissenschaftliches Experiment betrieben. Viele Wissenschaftler sind sich einig, dass bereits beobachtete Klimaveraenderungen auf den Einfluss des Menschen zurueckzufuehren sind. Andere fordern hingegen weitere Untersuchungen und halten bis dahin eine weitere uneingeschraenkte Verwendung fossiler Energietraeger fuer gerechtfertigt. Dieser Beitrag fasst weitgehend anerkannte Fakten ueber Treibhausgasemissionen und Klimaveraenderungen zusammen und beschreibt die Rolle und den Einfluss der Energiewirtschaft.

  11. Strategic Global Climate Command?

    Science.gov (United States)

    Long, J. C. S.

    2016-12-01

    Researchers have been exploring geoengineering because Anthropogenic GHG emissions could drive the globe towards unihabitability for people, wildlife and vegetation. Potential global deployment of these technologies is inherently strategic. For example, solar radiation management to reflect more sunlight might be strategically useful during a period of time where the population completes an effort to cease emissions and carbon removal technologies might then be strategically deployed to move the atmospheric concentrations back to a safer level. Consequently, deployment of these global technologies requires the ability to think and act strategically on the part of the planet's governments. Such capacity most definitely does not exist today but it behooves scientists and engineers to be involved in thinking through how global command might develop because the way they do the research could support the development of a capacity to deploy intervention rationally -- or irrationally. Internationalizing research would get countries used to working together. Organizing the research in a step-wise manner where at each step scientists become skilled at explaining what they have learned, the quality of the information they have, what they don't know and what more they can do to reduce or handle uncertainty, etc. Such a process can increase societal confidence in being able to make wise decisions about deployment. Global capacity will also be enhanced if the sceintific establishment reinvents misssion driven research so that the programs will identify the systemic issues invovled in any proposed technology and systematically address them with research while still encouraging individual creativity. Geoengineering will diverge from climate science in that geoengineering research needs to design interventions for some publically desirable goal and investigates whether a proposed intervention will acheive desired outcomes. The effort must be a systems-engineering design problem

  12. Space Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R.

    1968-01-01

    This booklet discusses three kinds of space radiation, cosmic rays, Van Allen Belts, and solar plasma. Cosmic rays are penetrating particles that we cannot see, hear or feel, which come from distant stars. Van Allen Belts, named after their discoverer are great belts of protons and electrons that the earth has captured in its magnetic trap. Solar plasma is a gaseous, electrically neutral mixture of positive and negative ions that the sun spews out from convulsed regions on its surface.

  13. Radiation protection

    CERN Multimedia

    Radioactive Shipping Service

    2005-01-01

    The section of the radiation protection group in charge of shipping radioactive material would like to remind users that all radioactive material leaving CERN must be checked for radioactivity and must be shipped according to the procedure given at http://cern.ch/service-rp-shipping Do not hesitate to contact us for any question or control. Radioactive Shipping Service: service-rp-shipping@cern.ch Tél. 73171

  14. Radiation protection

    CERN Document Server

    2005-01-01

    The section of the Radiation Protection Group in charge of shipping radioactive material would like to remind users that all radioactive material leaving CERN must be checked for radioactivity and must be shipped according to the procedure given at http://cern.ch/service-rp-shipping Do not hesitate to contact us for any question or control. Radioactive Shipping Service: service-rp-shipping@cern.ch Tel. 73171

  15. Radiation protection

    CERN Multimedia

    2005-01-01

    The section of the Radiation Protection Group in charge of shipping radioactive material would like to remind users that all radioactive material leaving CERN must be checked for radioactivity and must be shipped according to the procedure given at http://cern.ch/service-rp-shipping Do not hesitate to contact us for any question or control. Radioactive Shipping Service: service-rp-shipping@cern.ch Tél. 73171

  16. Global Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamoorthy, Sriram; Daily, Jeffrey A.; Vishnu, Abhinav; Palmer, Bruce J.

    2015-11-01

    Global Arrays (GA) is a distributed-memory programming model that allows for shared-memory-style programming combined with one-sided communication, to create a set of tools that combine high performance with ease-of-use. GA exposes a relatively straightforward programming abstraction, while supporting fully-distributed data structures, locality of reference, and high-performance communication. GA was originally formulated in the early 1990’s to provide a communication layer for the Northwest Chemistry (NWChem) suite of chemistry modeling codes that was being developed concurrently.

  17. Radiatively Generated $\

    CERN Document Server

    Joshipura, A S; Joshipura, Anjan S.; Rindani, Saurabh D.

    2003-01-01

    We study the consequences of assuming that the mass scale $\\Delta_{odot}$ corresponding to the solar neutrino oscillations and mixing angle $U_{e3}$ corresponding to the electron neutrino oscillation at CHOOZ are radiatively generated through the standard electroweak gauge interactions. All the leptonic mass matrices having zero $\\Delta_{odot}$ and $U_{e3}$ at a high scale lead to a unique low energy value for the $\\Delta_{odot}$ which is determined by the (known) size of the radiative corrections, solar and the atmospheric mixing angle and the Majorana mass of the neutrino observed in neutrinoless double beta decay. This prediction leads to the following consequences: ($i$) The MSSM radiative corrections generate only the dark side of the solar neutrino solutions. ($ii$) The inverted mass hierarchy ($m,-m,0$) at the high scale fails in generating the LMA solution but it can lead to the LOW or vacuum solutions. ($iii$) The $\\Delta_{odot}$ generated in models with maximal solar mixing at a high scale is zero t...

  18. Radiation Engineering for Designers

    Science.gov (United States)

    Pellish, Jonathan A.

    2015-01-01

    This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

  19. Acute Radiation Syndrome

    Science.gov (United States)

    ... Matters Information on Specific Types of Emergencies Acute Radiation Syndrome (ARS): A Fact Sheet for the Public ... is called the radiation dose. People exposed to radiation will get ARS only if: The radiation dose ...

  20. Chest radiation - discharge

    Science.gov (United States)

    Radiation - chest - discharge; Cancer - chest radiation; Lymphoma - chest radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after your first treatment: It may be hard ...

  1. Risk Factors: Radiation

    Science.gov (United States)

    Radiation of certain wavelengths, called ionizing radiation, has enough energy to damage DNA and cause cancer. Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation.

  2. Radiation Engineering for Designers

    Science.gov (United States)

    Pellish, Jonathan A.

    2015-01-01

    This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

  3. Global Properties of Solar Flares

    CERN Document Server

    Hudson, Hugh S

    2011-01-01

    This article broadly reviews our knowledge of solar flares. There is a particular focus on their global properties, as opposed to the microphysics such as that needed for magnetic reconnection or particle acceleration as such. Indeed solar flares will always remain in the domain of remote sensing, so we cannot observe the microscales directly and must understand the basic physics entirely via the global properties plus theoretical inference. The global observables include the general energetics -radiation in flares and mass loss in coronal mass ejections (CMEs) - and the formation of different kinds of ejection and global wave disturbance: the type II radio-burst exciter, the Moreton wave, the EIT "wave," and the "sunquake" acoustic waves in the solar interior. Flare radiation and CME kinetic energy can have comparable magnitudes, of order 10^32 erg each for an X-class event, with the bulk of the radiant energy in the visible-UV continuum. We argue that the impulsive phase of the flare dominates the energetic...

  4. Elements of change 1994. Climate-radiation feedbacks: The current state of the science

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    This report presents the details of the Climate-Radiation Feedback summer seminar. Topics include: radiative transfer; radiative properties of clouds; absorption of radiation in the atmosphere due to clouds; global cloud climatology; aerosols; general circulation models; and convection. Individual papers have been indexed separately for the database.

  5. Environmental assessment for the Atmospheric Radiation Measurement (ARM) Program: Southern Great Plains Cloud and Radiation Testbed (CART) site

    Energy Technology Data Exchange (ETDEWEB)

    Policastro, A.J.; Pfingston, J.M.; Maloney, D.M.; Wasmer, F.; Pentecost, E.D.

    1992-03-01

    The Atmospheric Radiation Measurement (ARM) Program is aimed at supplying improved predictive capability of climate change, particularly the prediction of cloud-climate feedback. The objective will be achieved by measuring the atmospheric radiation and physical and meteorological quantities that control solar radiation in the earth`s atmosphere and using this information to test global climate and related models. The proposed action is to construct and operate a Cloud and Radiation Testbed (CART) research site in the southern Great Plains as part of the Department of Energy`s Atmospheric Radiation Measurement Program whose objective is to develop an improved predictive capability of global climate change. The purpose of this CART research site in southern Kansas and northern Oklahoma would be to collect meteorological and other scientific information to better characterize the processes controlling radiation transfer on a global scale. Impacts which could result from this facility are described.

  6. Global environmental policy; Globale Umweltpolitik

    Energy Technology Data Exchange (ETDEWEB)

    Varwick, J. (ed.)

    2008-07-01

    For some years, the interest in global environmental problems and global environmental policy increased substantially. In order to prevent a sustainable and irreversible damage of the global ecological systems, it requires an ecological restructuring of the economy of the industrial nations and a environmental compatible development in the developing countries. Under this aspect, the book under consideration dedicates itself to this problem by means of five scientific contributions: (a) The principle sustainability (Felix Ekardt); (b) Climate change as a world problem (Andreas Rechkemmer); (c) The role of the pioneer of the European Union in the international climate policy: Successes and challenges (Sebastian Oberthuer); (d) Cause for conflict water (Tobias Lindenberg); (e) Environmental political instruments in theory and practice (Johanna Reichenbach/Till Requate). Instruction practice also is concerned with a cross section topic consisting of environmental and European politics: Competent instructions concerning to the European Union - an instruction series for the secondary school I (George Wiesseno, Valentin Eck). Two forum contributions go beyond the topic: (a) Against rigid (society-)political borders in the science (Tim Engartner); (b) Elections in Hamburg - Schwarz-Gruen as new coalition model for the federation? In the column 'the current topic' Gotthard Breit reports on the protests against China on the occasion of the Olympic Games 2008. The author focuses some strangenesses in the debate and pleads for a sober view of the topic. With a report on 'the Beutelsbacher discussions' at 18th to 20th February, 2008, Timo Web finishes this book.

  7. Global teaching of global seismology

    Science.gov (United States)

    Stein, S.; Wysession, M.

    2005-12-01

    Our recent textbook, Introduction to Seismology, Earthquakes, & Earth Structure (Blackwell, 2003) is used in many countries. Part of the reason for this may be our deliberate attempt to write the book for an international audience. This effort appears in several ways. We stress seismology's long tradition of global data interchange. Our brief discussions of the science's history illustrate the contributions of scientists around the world. Perhaps most importantly, our discussions of earthquakes, tectonics, and seismic hazards take a global view. Many examples are from North America, whereas others are from other areas. Our view is that non-North American students should be exposed to North American examples that are type examples, and that North American students should be similarly exposed to examples elsewhere. For example, we illustrate how the Euler vector geometry changes a plate boundary from spreading, to strike-slip, to convergence using both the Pacific-North America boundary from the Gulf of California to Alaska and the Eurasia-Africa boundary from the Azores to the Mediterranean. We illustrate diffuse plate boundary zones using western North America, the Andes, the Himalayas, the Mediterranean, and the East Africa Rift. The subduction zone discussions examine Japan, Tonga, and Chile. We discuss significant earthquakes both in the U.S. and elsewhere, and explore hazard mitigation issues in different contexts. Both comments from foreign colleagues and our experience lecturing overseas indicate that this approach works well. Beyond the specifics of our text, we believe that such a global approach is facilitated by the international traditions of the earth sciences and the world youth culture that gives students worldwide common culture. For example, a video of the scene in New Madrid, Missouri that arose from a nonsensical earthquake prediction in 1990 elicits similar responses from American and European students.

  8. Diffuse solar radiation and associated meteorological parameters in India

    Directory of Open Access Journals (Sweden)

    A. B. Bhattacharya

    Full Text Available Solar diffuse radiation data including global radiation, shortwave and longwave balances, net radiation and sunshine hours have been extensively analyzed to study the variation of diffuse radiation with turbidity and cloud discharges appearing in the form of atmospherics over the tropics. Results of surface radiation measurements at Calcutta, Poona, Delhi and Madras are presented together with some meteorological parameters. The monthly values of diffuse radiation and the monthly ratios of diffuse to global solar radiation have been examined, with a special emphasis in relation to the noise level of atmospherics at Calcutta in the very low frequency band. The results exhibit some definite seasonal changes which appear to be in close agreement with one another.

  9. Global gamesmanship.

    Science.gov (United States)

    MacMillan, Ian C; van Putten, Alexander B; McGrath, Rita Gunther

    2003-05-01

    Competition among multinationals these days is likely to be a three-dimensional game of global chess: The moves an organization makes in one market are designed to achieve goals in another in ways that aren't immediately apparent to its rivals. The authors--all management professors-call this approach "competing under strategic interdependence," or CSI. And where this interdependence exists, the complexity of the situation can quickly overwhelm ordinary analysis. Indeed, most business strategists are terrible at anticipating the consequences of interdependent choices, and they're even worse at using interdependency to their advantage. In this article, the authors offer a process for mapping the competitive landscape and anticipating how your company's moves in one market can influence its competitive interactions in others. They outline the six types of CSI campaigns--onslaughts, contests, guerrilla campaigns, feints, gambits, and harvesting--available to any multiproduct or multimarket corporation that wants to compete skillfully. They cite real-world examples such as the U.S. pricing battle Philip Morris waged with R.J. Reynolds--not to gain market share in the domestic cigarette market but to divert R.J. Reynolds's resources and attention from the opportunities Philip Morris was pursuing in Eastern Europe. And, using data they collected from their studies of consumer-products companies Procter & Gamble and Unilever, the authors describe how to create CSI tables and bubble charts that present a graphical look at the competitive landscape and that may uncover previously hidden opportunities. The CSI mapping process isn't just for global corporations, the authors explain. Smaller organizations that compete with a portfolio of products in just one national or regional market may find it just as useful for planning their next business moves.

  10. Global Mindset in Context

    DEFF Research Database (Denmark)

    Nielsen, Rikke Kristine

    2017-01-01

    This paper addresses the call for identification of organizational contingencies related to global mindset, exploration of different forms of global mindset and their relationship with global strategies (Osland, Bird, Mendenhall & Osland, 2006). To this end, this paper explores global mindset...

  11. Thermodynamics of radiation modes

    Energy Technology Data Exchange (ETDEWEB)

    Pina, Eduardo; De la Selva, Sara Maria Teresa [Departamento de Fisica, Universidad Autonoma Metropolitana - Iztapalapa, PO Box 55 534, Mexico, D F, 09340 (Mexico)], E-mail: pge@xanum.uam.mx, E-mail: tere@xanum.uam.mx

    2010-03-15

    We study the equilibrium thermodynamics of the electromagnetic radiation in a cavity of a given volume and temperature. We found three levels of description, the thermodynamics of one mode, the thermodynamics of the distribution of frequencies in a band by summing over the frequencies in it and the global thermodynamics by summing over all the frequencies. One equation relating frequency and volume is used to define the thermodynamics of one mode, and to explain the mystery of the frequency-dependent quantities having a similar behaviour to the non-frequency-dependent quantities for some thermodynamic equations and different behaviour for others. Besides, this frequency-volume relation is used to count the number of modes in a band of frequency.

  12. Estimation of Hourly Solar Radiation at the Surface under Cloudless Conditions on the Tibetan Plateau Using a Simple Radiation Model

    Institute of Scientific and Technical Information of China (English)

    LIANG Hong; ZHANG Renhe; LIU Jingmiao; SUN Zhian; CHENG Xinghong

    2012-01-01

    In this study,the clear sky hourly global and net solar irradiances at the surface determined using SUNFLUX,a simple parameterization scheme,for three stations (Gaize,Naqu,and Lhasa) on the Tibetan Plateau were evaluated against observation data.Our modeled results agree well with observations.The correlation coefficients between modeled and observed values were >0.99 for all three stations.The relative error of modeled results,in average was < 7%,and the root-mean-square variance was < 27 W m-2.The solar irradiances in the radiation model were slightly overestimated compared with observation data;there were at least two likely causes.First,the radiative effects of aerosols were not included in the radiation model.Second,solar irradiances determined by thermopile pyranometers include a thermal offset error that causes solar radiation to be slightly underestimated.The solar radiation absorbed by the ozone and water vapor was estimated. The results show that monthly mean solar radiation absorbed by the ozone is < 2% of the global solar radiation (< 14 W m-2).Solar radiation absorbed by water vapor is stronger in summer than in winter.The maximum amount of monthly mean solar radiation absorbed by water vapor can be up to 13% of the global solar radiation (95W m-2).This indicates that water vapor measurements with high precision are very important for precise determination of solar radiation.

  13. Global VTEC-modelling in near real-time based on space geodetic techniques, adapted B-spline expansions and Kalman-filtering including observations of the Sun's radiation

    Science.gov (United States)

    Börger, Klaus; Schmidt, Michael; Dettmering, Denise; Limberger, Marco; Erdogan, Eren; Seitz, Florian; Brandert, Sylvia; Görres, Barbara; Kersten, Wilhelm; Bothmer, Volker; Hinrichs, Johannes; Venzmer, Malte; Mrotzek, Niclas

    2016-04-01

    Today, the observations of space geodetic techniques are usually available with a rather low latency which applies to space missions observing the solar terrestrial environment, too. Therefore, we can use all these measurements in near real-time to compute and to provide ionosphere information, e.g. the vertical total electron content (VTEC). GSSAC and BGIC support a project aiming at a service for providing ionosphere information. This project is called OPTIMAP, meaning "Operational Tool for Ionosphere Mapping and Prediction"; the scientific work is mainly done by the German Geodetic Research Institute of the Technical University Munich (DGFI-TUM) and the Institute for Astrophysics of the University of Goettingen (IAG). The OPTIMAP strategy for providing ionosphere target quantities of high quality, such as VTEC or the electron density, includes mathematical approaches and tools allowing for the model adaptation to the real observational scenario as a significant improvement w.r.t. the traditional well-established methods. For example, OPTIMAP combines different observation types such as GNSS (GPS, GLONASS), Satellite Altimetry (Jason-2), DORIS as well as radio-occultation measurements (FORMOSAT#3/COSMIC). All these observations run into a Kalman-filter to compute global ionosphere maps, i.e. VTEC, for the current instant of time and as a forecast for a couple of subsequent days. Mathematically, the global VTEC is set up as a series expansion in terms of two-dimensional basis functions defined as tensor products of trigonometric B-splines for longitude and polynomial B-splines for latitude. Compared to the classical spherical harmonics, B-splines have a localizing character and, therefore, can handle an inhomogeneous data distribution properly. Finally, B-splines enable a so-called multi-resolution-representation (MRR) enabling the combination of global and regional modelling approaches. In addition to the geodetic measurements, Sun observations are pre

  14. cambio global

    Directory of Open Access Journals (Sweden)

    B. Alonso

    2006-01-01

    Full Text Available Un avance significativo dentro del área de la ecología sólo se podrá lograr con la adopción generalizada de un sistema basado en el uso compartido de los datos entre científicos. Esta práctica, apoyada por el desarrollo de metadatos precisos que acompañen a los propios datos, conseguirá aumentar la escala temporal y espacial de los objetos de estudio, ventajas evidentes en un área en la que cuestiones de carácter global como el estudio de los efectos del cambio climático van adquiriendo cada vez mayor importancia. En la actualidad existen numerosos grupos de científicos que trabajan voluntariamente en el desarrollo de herramientas que faciliten a los científicos la documentación y el almacenaje de sus datos. Asimismo, Internet está demostrando ser un potente instrumento para compartirlos. Aprovechar estos recursos es decisión nuestra.