WorldWideScience

Sample records for stretched-grid model intercomparison

  1. Simulating the characteristics of tropical cyclones over the South West Indian Ocean using a Stretched-Grid Global Climate Model

    Science.gov (United States)

    Maoyi, Molulaqhooa L.; Abiodun, Babatunde J.; Prusa, Joseph M.; Veitch, Jennifer J.

    2018-03-01

    Tropical cyclones (TCs) are one of the most devastating natural phenomena. This study examines the capability of a global climate model with grid stretching (CAM-EULAG, hereafter CEU) in simulating the characteristics of TCs over the South West Indian Ocean (SWIO). In the study, CEU is applied with a variable increment global grid that has a fine horizontal grid resolution (0.5° × 0.5°) over the SWIO and coarser resolution (1° × 1°—2° × 2.25°) over the rest of the globe. The simulation is performed for the 11 years (1999-2010) and validated against the Joint Typhoon Warning Center (JTWC) best track data, global precipitation climatology project (GPCP) satellite data, and ERA-Interim (ERAINT) reanalysis. CEU gives a realistic simulation of the SWIO climate and shows some skill in simulating the spatial distribution of TC genesis locations and tracks over the basin. However, there are some discrepancies between the observed and simulated climatic features over the Mozambique channel (MC). Over MC, CEU simulates a substantial cyclonic feature that produces a higher number of TC than observed. The dynamical structure and intensities of the CEU TCs compare well with observation, though the model struggles to produce TCs with a deep pressure centre as low as the observed. The reanalysis has the same problem. The model captures the monthly variation of TC occurrence well but struggles to reproduce the interannual variation. The results of this study have application in improving and adopting CEU for seasonal forecasting over the SWIO.

  2. ERRICCA radon model intercomparison exercise

    International Nuclear Information System (INIS)

    Andersen, C.E.; Albarracin, D.; Csige, I.; Graaf, E.R. van der; Jiranek, M.; Rehs, B.; Svoboda, Z.; Toro, L.

    1999-04-01

    Numerical models based on finite-difference or finite-element methods are used by various research groups in studies of radon-222 transport through soil and building materials. Applications range from design of radon remediation systems to more fundamental studies of radon transport. To ascertain that results obtained with these models are of good quality, it is necessary that such models are tested. This document reports on a benchmark test organized by the EU project ERRICCA: European Research into Radon in Construction Concerted Action. The test comprises the following cases: 1) Steady-state diffusive radon profiles in dry and wet soils, 2) steady-state entry of soil gas and radon into a house, 3) time-dependent radon exhalation from a building-material sample. These cases cover features such as: soil heterogeneity, anisotropy, 3D-effects, time dependency, combined advective and diffusive transport of radon, flux calculations, and partitioning of radon between air and water in soil pores. Seven groups participated in the intercomparison. All groups submitted results without knowing the results of others. For these results, relatively large group-to-group discrepancies were observed. Because of this, all groups scrutinized their computations (once more) and engaged in follow-up discussions with others. During this debugging process, problems were indeed identified (and eliminated). The accordingly revised results were in better agreement than those reported initially. Some discrepancies, however, still remain. All in all, it seems that the exercise has served its purpose and stimulated improvements relating to the quality of numerical modelling of radon transport. To maintain a high quality of modelling, it is recommended that additional exercises are carried out. (au)

  3. ERRICCA radon model intercomparison exercise

    DEFF Research Database (Denmark)

    Andersen, C.E.; Albarracín, D.; Csige, I.

    1999-01-01

    -state diffusive radon profiles in dry and wet soils, (2) steady-state entry of soil gas and radon into a house, (3) time-dependent radon exhalation from abuilding-material sample. These cases cover features such as: soil heterogeneity, anisotropy, 3D-effects, time dependency, combined advective and diffusive......, still remain. All in all, it seems that the exercise has served its purpose and stimulated improvements relating to the quality of numerical modelling of radon transport. To maintain a high quality of modelling, it is recommendedthat additional exercises are carried out....

  4. Radiative-convective equilibrium model intercomparison project

    Science.gov (United States)

    Wing, Allison A.; Reed, Kevin A.; Satoh, Masaki; Stevens, Bjorn; Bony, Sandrine; Ohno, Tomoki

    2018-03-01

    RCEMIP, an intercomparison of multiple types of models configured in radiative-convective equilibrium (RCE), is proposed. RCE is an idealization of the climate system in which there is a balance between radiative cooling of the atmosphere and heating by convection. The scientific objectives of RCEMIP are three-fold. First, clouds and climate sensitivity will be investigated in the RCE setting. This includes determining how cloud fraction changes with warming and the role of self-aggregation of convection in climate sensitivity. Second, RCEMIP will quantify the dependence of the degree of convective aggregation and tropical circulation regimes on temperature. Finally, by providing a common baseline, RCEMIP will allow the robustness of the RCE state across the spectrum of models to be assessed, which is essential for interpreting the results found regarding clouds, climate sensitivity, and aggregation, and more generally, determining which features of tropical climate a RCE framework is useful for. A novel aspect and major advantage of RCEMIP is the accessibility of the RCE framework to a variety of models, including cloud-resolving models, general circulation models, global cloud-resolving models, single-column models, and large-eddy simulation models.

  5. Regional Data Assimilation Using a Stretched-Grid Approach and Ensemble Calculations

    Science.gov (United States)

    Fox-Rabinovitz, M. S.; Takacs, L. L.; Govindaraju, R. C.; Atlas, Robert (Technical Monitor)

    2002-01-01

    The global variable resolution stretched grid (SG) version of the Goddard Earth Observing System (GEOS) Data Assimilation System (DAS) incorporating the GEOS SG-GCM (Fox-Rabinovitz 2000, Fox-Rabinovitz et al. 2001a,b), has been developed and tested as an efficient tool for producing regional analyses and diagnostics with enhanced mesoscale resolution. The major area of interest with enhanced regional resolution used in different SG-DAS experiments includes a rectangle over the U.S. with 50 or 60 km horizontal resolution. The analyses and diagnostics are produced for all mandatory levels from the surface to 0.2 hPa. The assimilated regional mesoscale products are consistent with global scale circulation characteristics due to using the SG-approach. Both the stretched grid and basic uniform grid DASs use the same amount of global grid-points and are compared in terms of regional product quality.

  6. The third RAdiation transfer Model Intercomparison (RAMI) exercise: Documenting progress in canopy reflectance models

    NARCIS (Netherlands)

    Widlowski, J.L.; Taberner, M.; Pinty, B.; Bruniquel-Pinel, V.; Disney, M.I.; Fernandes, R.; Gastellu-Etchegorry, J.P.; Gobron, N.; Kuusk, A.; Lavergne, T.; LeBlanc, S.; Lewis, P.E.; Martin, E.; Mõttus, M.; North, P.R.J.; Qin, W.; Robustelli, M.; Rochdi, N.; Ruiloba, R.; Thompson, R.; Verhoef, W.; Verstraete, M.M.; Xie, D.

    2007-01-01

    [1] The Radiation Transfer Model Intercomparison ( RAMI) initiative benchmarks canopy reflectance models under well-controlled experimental conditions. Launched for the first time in 1999, this triennial community exercise encourages the systematic evaluation of canopy reflectance models on a

  7. Third Radiation Transfer Model Intercomparison (RAMI) exercise : Documenting progress in canopy reflectance models

    NARCIS (Netherlands)

    Widlowski, J.-L.; Taberner, M.; Pinty, B.; Bruniquel-Pinel, V.; Disney, M.; Fernandes, R.; Gastellu-Etchegorry, J.P.; Gobron, N.; Kuusk, A.; Lavergne, T.; Leblanc, S.; Lewis, P.E.; Martin, E.; Mottus, M.; North, P.R.J.; Qin, W.; Robustelli, M.; Rochdi, N.; Ruiloba, R.; Soler, C.; Thompson, R.; Verhoef, W.; Xie, D.; Thompson, R.

    2007-01-01

    The Radiation Transfer Model Intercomparison (RAMI) initiative benchmarks canopy reflectance models under well‐controlled experimental conditions. Launched for the first time in 1999, this triennial community exercise encourages the systematic evaluation of canopy reflectance models on a voluntary

  8. The Geoengineering Model Intercomparison Project (GeoMIP)

    KAUST Repository

    Kravitz, Ben

    2011-01-31

    To evaluate the effects of stratospheric geoengineering with sulphate aerosols, we propose standard forcing scenarios to be applied to multiple climate models to compare their results and determine the robustness of their responses. Thus far, different modeling groups have used different forcing scenarios for both global warming and geoengineering, complicating the comparison of results. We recommend four experiments to explore the extent to which geoengineering might offset climate change projected in some of the Climate Model Intercomparison Project 5 experiments. These experiments focus on stratospheric aerosols, but future experiments under this framework may focus on different means of geoengineering. © 2011 Royal Meteorological Society.

  9. Results of the Marine Ice Sheet Model Intercomparison Project, MISMIP

    Directory of Open Access Journals (Sweden)

    F. Pattyn

    2012-05-01

    Full Text Available Predictions of marine ice-sheet behaviour require models that are able to robustly simulate grounding line migration. We present results of an intercomparison exercise for marine ice-sheet models. Verification is effected by comparison with approximate analytical solutions for flux across the grounding line using simplified geometrical configurations (no lateral variations, no effects of lateral buttressing. Unique steady state grounding line positions exist for ice sheets on a downward sloping bed, while hysteresis occurs across an overdeepened bed, and stable steady state grounding line positions only occur on the downward-sloping sections. Models based on the shallow ice approximation, which does not resolve extensional stresses, do not reproduce the approximate analytical results unless appropriate parameterizations for ice flux are imposed at the grounding line. For extensional-stress resolving "shelfy stream" models, differences between model results were mainly due to the choice of spatial discretization. Moving grid methods were found to be the most accurate at capturing grounding line evolution, since they track the grounding line explicitly. Adaptive mesh refinement can further improve accuracy, including fixed grid models that generally perform poorly at coarse resolution. Fixed grid models, with nested grid representations of the grounding line, are able to generate accurate steady state positions, but can be inaccurate over transients. Only one full-Stokes model was included in the intercomparison, and consequently the accuracy of shelfy stream models as approximations of full-Stokes models remains to be determined in detail, especially during transients.

  10. Firn Model Intercomparison Experiment (FirnMICE)

    DEFF Research Database (Denmark)

    Lundin, Jessica M.D.; Stevens, C. Max; Arthern, Robert

    2017-01-01

    Evolution of cold dry snow and firn plays important roles in glaciology; however, the physical formulation of a densification law is still an active research topic. We forced eight firn-densification models and one seasonal-snow model in six different experiments by imposing step changes in tempe...

  11. Arctic Ocean Model Intercomparison Using Sound Speed

    Science.gov (United States)

    Dukhovskoy, D. S.; Johnson, M. A.

    2002-05-01

    The monthly and annual means from three Arctic ocean - sea ice climate model simulations are compared for the period 1979-1997. Sound speed is used to integrate model outputs of temperature and salinity along a section between Barrow and Franz Josef Land. A statistical approach is used to test for differences among the three models for two basic data subsets. We integrated and then analyzed an upper layer between 2 m - 50 m, and also a deep layer from 500 m to the bottom. The deep layer is characterized by low time-variability. No high-frequency signals appear in the deep layer having been filtered out in the upper layer. There is no seasonal signal in the deep layer and the monthly means insignificantly oscillate about the long-period mean. For the deep ocean the long-period mean can be considered quasi-constant, at least within the 19 year period of our analysis. Thus we assumed that the deep ocean would be the best choice for comparing the means of the model outputs. The upper (mixed) layer was chosen to contrast the deep layer dynamics. There are distinct seasonal and interannual signals in the sound speed time series in this layer. The mixed layer is a major link in the ocean - air interaction mechanism. Thus, different mean states of the upper layer in the models might cause different responses in other components of the Arctic climate system. The upper layer also strongly reflects any differences in atmosphere forcing. To compare data from the three models we have used a one-way t-test for the population mean, the Wilcoxon one-sample signed-rank test (when the requirement of normality of tested data is violated), and one-way ANOVA method and F-test to verify our hypothesis that the model outputs have the same mean sound speed. The different statistical approaches have shown that all models have different mean characteristics of the deep and upper layers of the Arctic Ocean.

  12. International codes and model intercomparison for intermediate energy activation yields

    International Nuclear Information System (INIS)

    Rolf, M.; Nagel, P.

    1997-01-01

    The motivation for this intercomparison came from data needs of accelerator-based waste transmutation, energy amplification and medical therapy. The aim of this exercise is to determine the degree of reliability of current nuclear reaction models and codes when calculating activation yields in the intermediate energy range up to 5000 MeV. Emphasis has been placed for a wide range of target elements ( O, Al, Fe, Co, Zr and Au). This work is mainly based on calculation of (P,xPyN) integral cross section for incident proton. A qualitative description of some of the nuclear models and code options employed is made. The systematics of graphical presentation of the results allows a quick quantitative measure of agreement or deviation. This code intercomparison highlights the fact that modeling calculations of energy activation yields may at best have uncertainties of a factor of two. The causes of such discrepancies are multi-factorial. Problems are encountered which are connected with the calculation of nuclear masses, binding energies, Q-values, shell effects, medium energy fission and Fermi break-up. (A.C.)

  13. Community Intercomparison Suite (CIS) v1.4.0: A tool for intercomparing models and observations

    NARCIS (Netherlands)

    Watson-Parris, Duncan; Schutgens, Nick; Cook, Nicholas; Kipling, Zak; Kershaw, Philip; Gryspeerdt, Edward; Lawrence, Bryan; Stier, Philip

    2016-01-01

    The Community Intercomparison Suite (CIS) is an easy-to-use command-line tool which has been developed to allow the straightforward intercomparison of remote sensing, in-situ and model data. While there are a number of tools available for working with climate model data, the large diversity of

  14. A River Model Intercomparison Project in Preparation for SWOT

    Science.gov (United States)

    David, C. H.; Andreadis, K.; Famiglietti, J. S.; Beighley, E.; Boone, A. A.; Yamazaki, D.; Paiva, R. C. D.; Fleischmann, A. S.; Collischonn, W.; Fisher, C. K.; Kim, H.; Biancamaria, S.

    2017-12-01

    The Surface Water and Ocean Topography (SWOT) mission is currently scheduled to launch at the beginning of next decade. SWOT is expected to retrieve unprecedented measurements of water extent, elevation, and slope in the largest terrestrial water bodies. Such potential transformative information motivates the investigation of our ability to ingest the associated data into continental-scale models of terrestrial hydrology. In preparation for the expected SWOT observations, an inter-comparison of continental-scale river models is being performed. This comparison experiment focuses on four of the world's largest river basins: the Amazon, the Mississippi, the Niger, and the Saint-Lawrence. This ongoing project focuses on two main research questions: 1) How can we best prepare for the expected SWOT continental to global measurements before SWOT even flies?, and 2) What is the added value of including SWOT terrestrial measurements into global hydro models for enhancing our understanding of the terrestrial water cycle and the climate system? We present here the results of the second year of this project which now includes simulations from six numerical models of rivers over the Mississippi and sheds light on the implications of various modeling choices on simulation quality as well as on the potential impact of SWOT observations.

  15. Blind intercomparison of nuclear models for predicting charged particle emission

    International Nuclear Information System (INIS)

    Shibata, K.; Cierjacks, S.

    1994-01-01

    Neutron activation data are important for dosimetry, radiation-damage and production of long-lived activities. For fusion energy applications, it is required to develop 'low-activation materials' from the viewpoints of safety, maintenance and waste disposal. Existing evaluated activation cross-section libraries are to a large extent based on nuclear-model calculations. The former Nuclear Energy Agency Nuclear Data Committee, NEANDC, (presently replaced by the NEA Nuclear Science Committee) organized the working group on activation cross sections. The first meeting of the group was held in 1989, and it was then agreed that a blind intercomparison of nuclear-model calculations should be undertaken in order to test the predictive power of the theoretical calculations. As a first stage the working group selected the reactions 60g Co(n,p) 60 Fe and 60m Co(n,p) 60 Fe, for which no experimental data were available, in the energy range from 1 to 20 MeV. The preliminary results compiled at the NEA Data Bank were sent to each participant and a meeting was held during the International Conference on Nuclear Data for Science and Technology in Julich 1991 to discuss the results. Following the outcome of the discussion in Julich, it was decided to extend this intercomparison. In the second-stage calculation, the same optical-model parameters were employed for neutrons, protons and α-particles, i.e., V = 50 MeV, W = 10 MeV, r = 1.25 fm and a = 0.6 fm with the Woods-Saxon volume-type form factors. No spin-orbit interaction was considered. Concerning the level density, the Fermi gas model with a = A/8 MeV -1 was assumed without pairing corrections. Moreover, gamma-ray competition was neglected to simplify the calculation. This report describes the final results of the blind comparison. Section 2 deals with a survey of the received contributions. The final results are graphically presented in section 3. 67 figs., 1 tab., 12 refs

  16. Statistical intercomparison of global climate models: A common principal component approach with application to GCM data

    International Nuclear Information System (INIS)

    Sengupta, S.K.; Boyle, J.S.

    1993-05-01

    Variables describing atmospheric circulation and other climate parameters derived from various GCMs and obtained from observations can be represented on a spatio-temporal grid (lattice) structure. The primary objective of this paper is to explore existing as well as some new statistical methods to analyze such data structures for the purpose of model diagnostics and intercomparison from a statistical perspective. Among the several statistical methods considered here, a new method based on common principal components appears most promising for the purpose of intercomparison of spatio-temporal data structures arising in the task of model/model and model/data intercomparison. A complete strategy for such an intercomparison is outlined. The strategy includes two steps. First, the commonality of spatial structures in two (or more) fields is captured in the common principal vectors. Second, the corresponding principal components obtained as time series are then compared on the basis of similarities in their temporal evolution

  17. Intercomparison of middle-atmospheric wind in observations and models

    Directory of Open Access Journals (Sweden)

    R. Rüfenacht

    2018-04-01

    Full Text Available Wind profile information throughout the entire upper stratosphere and lower mesosphere (USLM is important for the understanding of atmospheric dynamics but became available only recently, thanks to developments in remote sensing techniques and modelling approaches. However, as wind measurements from these altitudes are rare, such products have generally not yet been validated with (other observations. This paper presents the first long-term intercomparison of wind observations in the USLM by co-located microwave radiometer and lidar instruments at Andenes, Norway (69.3° N, 16.0° E. Good correspondence has been found at all altitudes for both horizontal wind components for nighttime as well as daylight conditions. Biases are mostly within the random errors and do not exceed 5–10 m s−1, which is less than 10 % of the typically encountered wind speeds. Moreover, comparisons of the observations with the major reanalyses and models covering this altitude range are shown, in particular with the recently released ERA5, ECMWF's first reanalysis to cover the whole USLM region. The agreement between models and observations is very good in general, but temporally limited occurrences of pronounced discrepancies (up to 40 m s−1 exist. In the article's Appendix the possibility of obtaining nighttime wind information about the mesopause region by means of microwave radiometry is investigated.

  18. Results of the eruptive column model inter-comparison study

    Science.gov (United States)

    Costa, Antonio; Suzuki, Yujiro; Cerminara, M.; Devenish, Ben J.; Esposti Ongaro, T.; Herzog, Michael; Van Eaton, Alexa; Denby, L.C.; Bursik, Marcus; de' Michieli Vitturi, Mattia; Engwell, S.; Neri, Augusto; Barsotti, Sara; Folch, Arnau; Macedonio, Giovanni; Girault, F.; Carazzo, G.; Tait, S.; Kaminski, E.; Mastin, Larry G.; Woodhouse, Mark J.; Phillips, Jeremy C.; Hogg, Andrew J.; Degruyter, Wim; Bonadonna, Costanza

    2016-01-01

    This study compares and evaluates one-dimensional (1D) and three-dimensional (3D) numerical models of volcanic eruption columns in a set of different inter-comparison exercises. The exercises were designed as a blind test in which a set of common input parameters was given for two reference eruptions, representing a strong and a weak eruption column under different meteorological conditions. Comparing the results of the different models allows us to evaluate their capabilities and target areas for future improvement. Despite their different formulations, the 1D and 3D models provide reasonably consistent predictions of some of the key global descriptors of the volcanic plumes. Variability in plume height, estimated from the standard deviation of model predictions, is within ~ 20% for the weak plume and ~ 10% for the strong plume. Predictions of neutral buoyancy level are also in reasonably good agreement among the different models, with a standard deviation ranging from 9 to 19% (the latter for the weak plume in a windy atmosphere). Overall, these discrepancies are in the range of observational uncertainty of column height. However, there are important differences amongst models in terms of local properties along the plume axis, particularly for the strong plume. Our analysis suggests that the simplified treatment of entrainment in 1D models is adequate to resolve the general behaviour of the weak plume. However, it is inadequate to capture complex features of the strong plume, such as large vortices, partial column collapse, or gravitational fountaining that strongly enhance entrainment in the lower atmosphere. We conclude that there is a need to more accurately quantify entrainment rates, improve the representation of plume radius, and incorporate the effects of column instability in future versions of 1D volcanic plume models.

  19. Last interglacial temperature evolution – a model inter-comparison

    Directory of Open Access Journals (Sweden)

    P. Bakker

    2013-03-01

    Full Text Available There is a growing number of proxy-based reconstructions detailing the climatic changes that occurred during the last interglacial period (LIG. This period is of special interest, because large parts of the globe were characterized by a warmer-than-present-day climate, making this period an interesting test bed for climate models in light of projected global warming. However, mainly because synchronizing the different palaeoclimatic records is difficult, there is no consensus on a global picture of LIG temperature changes. Here we present the first model inter-comparison of transient simulations covering the LIG period. By comparing the different simulations, we aim at investigating the common signal in the LIG temperature evolution, investigating the main driving forces behind it and at listing the climate feedbacks which cause the most apparent inter-model differences. The model inter-comparison shows a robust Northern Hemisphere July temperature evolution characterized by a maximum between 130–125 ka BP with temperatures 0.3 to 5.3 K above present day. A Southern Hemisphere July temperature maximum, −1.3 to 2.5 K at around 128 ka BP, is only found when changes in the greenhouse gas concentrations are included. The robustness of simulated January temperatures is large in the Southern Hemisphere and the mid-latitudes of the Northern Hemisphere. For these regions maximum January temperature anomalies of respectively −1 to 1.2 K and −0.8 to 2.1 K are simulated for the period after 121 ka BP. In both hemispheres these temperature maxima are in line with the maximum in local summer insolation. In a number of specific regions, a common temperature evolution is not found amongst the models. We show that this is related to feedbacks within the climate system which largely determine the simulated LIG temperature evolution in these regions. Firstly, in the Arctic region, changes in the summer sea-ice cover control the evolution of LIG winter

  20. The ARM-GCSS Intercomparison Study of Single-Column Models and Cloud System Models

    International Nuclear Information System (INIS)

    Cederwall, R.T.; Rodriques, D.J.; Krueger, S.K.; Randall, D.A.

    1999-01-01

    The Single-Column Model (SCM) Working Group (WC) and the Cloud Working Group (CWG) in the Atmospheric Radiation Measurement (ARM) Program have begun a collaboration with the GEWEX Cloud System Study (GCSS) WGs. The forcing data sets derived from the special ARM radiosonde measurements made during the SCM Intensive Observation Periods (IOPs), the wealth of cloud and related data sets collected by the ARM Program, and the ARM infrastructure support of the SCM WG are of great value to GCSS. In return, GCSS brings the efforts of an international group of cloud system modelers to bear on ARM data sets and ARM-related scientific questions. The first major activity of the ARM-GCSS collaboration is a model intercomparison study involving SCMs and cloud system models (CSMs), also known as cloud-resolving or cloud-ensemble models. The SCM methodologies developed in the ARM Program have matured to the point where an intercomparison will help identify the strengths and weaknesses of various approaches. CSM simulations will bring much additional information about clouds to evaluate cloud parameterizations used in the SCMs. CSMs and SCMs have been compared successfully in previous GCSS intercomparison studies for tropical conditions. The ARM Southern Great Plains (SGP) site offers an opportunity for GCSS to test their models in continental, mid-latitude conditions. The Summer 1997 SCM IOP has been chosen since it provides a wide range of summertime weather events that will be a challenging test of these models

  1. Ice Sheet Model Intercomparison Project (ISMIP6) contribution to CMIP6

    NARCIS (Netherlands)

    Nowicki, Sophie M J; Payne, Anthony; Larour, Eric; Seroussi, Helene; Goelzer, Heiko|info:eu-repo/dai/nl/412549123; Lipscomb, William; Gregory, Jonathan; Abe-Ouchi, Ayako; Shepherd, Andrew

    2016-01-01

    Reducing the uncertainty in the past, present, and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model

  2. Crop rotation modelling-A European model intercomparison

    Czech Academy of Sciences Publication Activity Database

    Kollas, C.; Kersebaum, K. C.; Nendel, C.; Manevski, K.; Müller, C.; Palosuo, T.; Armas-Herrera, C.; Beaudoin, N.; Bindi, M.; Charefeddine, M.; Conradt, T.; Constantin, J.; Eitzinger, J.; Ewert, F.; Ferrise, R.; Gaiser, T.; de Cortazar-Atauri, I. G.; Giglio, L.; Hlavinka, Petr; Hoffman, H.; Hofmann, M.; Launay, M.; Manderscheid, R.; Mary, B.; Mirschel, W.; Moriondo, M.; Olesen, J. E.; Öztürk, I.; Pacholski, A.; Ripoche-Wachter, D.; Roggero, P. P.; Roncossek, S.; Rötter, R. P.; Ruget, F.; Sharif, B.; Trnka, Miroslav; Ventrella, D.; Waha, K.; Wegehenkel, M.; Weigel, H-J.; Wu, L.

    2015-01-01

    Roč. 70, oct (2015), s. 98-111 ISSN 1161-0301 Institutional support: RVO:67179843 Keywords : model ensemble * crop simulation models * catch crop * intermediate crop * treatment * Multi-year Subject RIV: GC - Agronomy Impact factor: 3.186, year: 2015

  3. EURADOS intercomparison on measurements and Monte Carlo modelling for the assessment of Americium in a USTUR leg phantom

    International Nuclear Information System (INIS)

    Lopez, M. A.; Broggio, D.; Capello, K.; Cardenas-Mendez, E.; El-Faramawy, N.; Franck, D.; James, A. C.; Kramer, G. H.; Lacerenza, G.; Lynch, T. P.; Navarro, J. F.; Navarro, T.; Perez, B.; Ruehm, W.; Tolmachev, S. Y.; Weitzenegger, E.

    2011-01-01

    A collaboration of the EURADOS working group on 'Internal Dosimetry' and the United States Transuranium and Uranium Registries (USTUR) has taken place to carry out an intercomparison on measurements and Monte Carlo modelling determining americium deposited in the bone of a USTUR leg phantom. Preliminary results and conclusions of this intercomparison exercise are presented here. (authors)

  4. Use of an operational model evaluation system for model intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Foster, K. T., LLNL

    1998-03-01

    The Atmospheric Release Advisory Capability (ARAC) is a centralized emergency response system used to assess the impact from atmospheric releases of hazardous materials. As part of an on- going development program, new three-dimensional diagnostic windfield and Lagrangian particle dispersion models will soon replace ARAC`s current operational windfield and dispersion codes. A prototype model performance evaluation system has been implemented to facilitate the study of the capabilities and performance of early development versions of these new models relative to ARAC`s current operational codes. This system provides tools for both objective statistical analysis using common performance measures and for more subjective visualization of the temporal and spatial relationships of model results relative to field measurements. Supporting this system is a database of processed field experiment data (source terms and meteorological and tracer measurements) from over 100 individual tracer releases.

  5. Model Intercomparison Study to Investigate a Dense Contaminant Plume in a Complex Hydrogeologic System

    International Nuclear Information System (INIS)

    Williams, Mark D.; Cole, Charles R.; Foley, Michael G.; Zinina, Galina A.; Zinin, Alexander I.; Vasil'Kova, Nelly A.; Samsonova, Lilia M.

    2001-01-01

    A joint Russian and U.S. model intercomparison study was undertaken for developing more realistic contaminant transport models of the Mayak Site, Southern Urals. The test problems were developed by the Russian Team based on their experience modeling contaminant migration near Lake Karachai. The intercomparison problems were designed to address lake and contaminant plume interactions, as well as river interactions and plume density effects. Different numerical codes were used. Overall there is good agreement between the results of both models. Features shown by both models include (1) the sinking of the plume below the lake, (2) the raising of the water table in the fresh water adjacent to the lake in response to the increased pressure from the dense plume, and (3) the formation of a second sinking plume in an area where evapotranspiration exceeded infiltration, thus increasing the solute concentrations above the source (i.e., lake) values

  6. The Agricultural Model Intercomparison and Improvement Project (AgMIP): Overview and Progress

    Science.gov (United States)

    Rosenzweig, C.; Hatfield, J.; Jones, J. W.; Ruane, A. C.

    2012-12-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) is an international effort to assess the state of global agricultural modeling and to understand climate impacts on the agricultural sector. AgMIP connects the climate science, crop modeling, and agricultural economic modeling communities to generate probabilistic projections of current and future climate impacts. The goals of AgMIP are to improve substantially the characterization of risk of hunger and world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. This presentation will describe the general approach of AgMIP and highlight its findings and activities. AgMIP crop model intercomparisons have been established for wheat (27 models participating), maize (25 models), and rice (15+ models), and are being established for sugarcane, soybean, sorghum/millet, and peanut. In coordination with these pilots, methodologies to utilize weather generators and downscaled climate simulations for agricultural applications are under development. An AgMIP global agricultural economics model intercomparison with participation of 11 international groups is ongoing, and a number of global biophysical models are currently being evaluated for future climate impacts on agricultural lands both as part of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) and for contribution to the IPCC Fifth Assessment Report (AR5). AgMIP is also organizing regional research efforts, and has already held workshops in South America, Sub-Saharan Africa, South Asia, Europe, and North America. Outcomes from these meetings have informed AgMIP activities, and 10 research teams from Sub-Saharan Africa and South Asia have been selected for project funding. Additional activities are planned for Australia and East Asia. As the AgMIP research community continues to work towards its goals, three key cross-cutting scientific challenges have emerged and are being

  7. Large-Scale Features of Pliocene Climate: Results from the Pliocene Model Intercomparison Project

    Science.gov (United States)

    Haywood, A. M.; Hill, D.J.; Dolan, A. M.; Otto-Bliesner, B. L.; Bragg, F.; Chan, W.-L.; Chandler, M. A.; Contoux, C.; Dowsett, H. J.; Jost, A.; hide

    2013-01-01

    Climate and environments of the mid-Pliocene warm period (3.264 to 3.025 Ma) have been extensively studied.Whilst numerical models have shed light on the nature of climate at the time, uncertainties in their predictions have not been systematically examined. The Pliocene Model Intercomparison Project quantifies uncertainties in model outputs through a coordinated multi-model and multi-mode data intercomparison. Whilst commonalities in model outputs for the Pliocene are clearly evident, we show substantial variation in the sensitivity of models to the implementation of Pliocene boundary conditions. Models appear able to reproduce many regional changes in temperature reconstructed from geological proxies. However, data model comparison highlights that models potentially underestimate polar amplification. To assert this conclusion with greater confidence, limitations in the time-averaged proxy data currently available must be addressed. Furthermore, sensitivity tests exploring the known unknowns in modelling Pliocene climate specifically relevant to the high latitudes are essential (e.g. palaeogeography, gateways, orbital forcing and trace gasses). Estimates of longer-term sensitivity to CO2 (also known as Earth System Sensitivity; ESS), support previous work suggesting that ESS is greater than Climate Sensitivity (CS), and suggest that the ratio of ESS to CS is between 1 and 2, with a "best" estimate of 1.5.

  8. A potato model intercomparison across varying climates and productivity levels

    DEFF Research Database (Denmark)

    H. Fleisher, David; Condori, Bruno; Quiroz, Roberto

    2017-01-01

    A potato crop multi-model assessment was conducted to quantify variation among models and evaluate responses to climate change. Nine modeling groups simulated agronomic and climatic responses at low- (Chinoli, Bolivia and Gisozi, Burundi) and high- (Jyndevad, Denmark and Washington, United States.......01). These are the first reported results quantifying uncertainty for tuber/root crops and suggest modeling assessments of climate change impact on potato may be improved using an ensemble approach....

  9. A potato model intercomparison across varying climates and productivity levels.

    Science.gov (United States)

    Fleisher, David H; Condori, Bruno; Quiroz, Roberto; Alva, Ashok; Asseng, Senthold; Barreda, Carolina; Bindi, Marco; Boote, Kenneth J; Ferrise, Roberto; Franke, Angelinus C; Govindakrishnan, Panamanna M; Harahagazwe, Dieudonne; Hoogenboom, Gerrit; Naresh Kumar, Soora; Merante, Paolo; Nendel, Claas; Olesen, Jorgen E; Parker, Phillip S; Raes, Dirk; Raymundo, Rubi; Ruane, Alex C; Stockle, Claudio; Supit, Iwan; Vanuytrecht, Eline; Wolf, Joost; Woli, Prem

    2017-03-01

    A potato crop multimodel assessment was conducted to quantify variation among models and evaluate responses to climate change. Nine modeling groups simulated agronomic and climatic responses at low-input (Chinoli, Bolivia and Gisozi, Burundi)- and high-input (Jyndevad, Denmark and Washington, United States) management sites. Two calibration stages were explored, partial (P1), where experimental dry matter data were not provided, and full (P2). The median model ensemble response outperformed any single model in terms of replicating observed yield across all locations. Uncertainty in simulated yield decreased from 38% to 20% between P1 and P2. Model uncertainty increased with interannual variability, and predictions for all agronomic variables were significantly different from one model to another (P < 0.001). Uncertainty averaged 15% higher for low- vs. high-input sites, with larger differences observed for evapotranspiration (ET), nitrogen uptake, and water use efficiency as compared to dry matter. A minimum of five partial, or three full, calibrated models was required for an ensemble approach to keep variability below that of common field variation. Model variation was not influenced by change in carbon dioxide (C), but increased as much as 41% and 23% for yield and ET, respectively, as temperature (T) or rainfall (W) moved away from historical levels. Increases in T accounted for the highest amount of uncertainty, suggesting that methods and parameters for T sensitivity represent a considerable unknown among models. Using median model ensemble values, yield increased on average 6% per 100-ppm C, declined 4.6% per °C, and declined 2% for every 10% decrease in rainfall (for nonirrigated sites). Differences in predictions due to model representation of light utilization were significant (P < 0.01). These are the first reported results quantifying uncertainty for tuber/root crops and suggest modeling assessments of climate change impact on potato may be

  10. IPRT polarized radiative transfer model intercomparison project - Three-dimensional test cases (phase B)

    Science.gov (United States)

    Emde, Claudia; Barlakas, Vasileios; Cornet, Céline; Evans, Frank; Wang, Zhen; Labonotte, Laurent C.; Macke, Andreas; Mayer, Bernhard; Wendisch, Manfred

    2018-04-01

    Initially unpolarized solar radiation becomes polarized by scattering in the Earth's atmosphere. In particular molecular scattering (Rayleigh scattering) polarizes electromagnetic radiation, but also scattering of radiation at aerosols, cloud droplets (Mie scattering) and ice crystals polarizes. Each atmospheric constituent produces a characteristic polarization signal, thus spectro-polarimetric measurements are frequently employed for remote sensing of aerosol and cloud properties. Retrieval algorithms require efficient radiative transfer models. Usually, these apply the plane-parallel approximation (PPA), assuming that the atmosphere consists of horizontally homogeneous layers. This allows to solve the vector radiative transfer equation (VRTE) efficiently. For remote sensing applications, the radiance is considered constant over the instantaneous field-of-view of the instrument and each sensor element is treated independently in plane-parallel approximation, neglecting horizontal radiation transport between adjacent pixels (Independent Pixel Approximation, IPA). In order to estimate the errors due to the IPA approximation, three-dimensional (3D) vector radiative transfer models are required. So far, only a few such models exist. Therefore, the International Polarized Radiative Transfer (IPRT) working group of the International Radiation Commission (IRC) has initiated a model intercomparison project in order to provide benchmark results for polarized radiative transfer. The group has already performed an intercomparison for one-dimensional (1D) multi-layer test cases [phase A, 1]. This paper presents the continuation of the intercomparison project (phase B) for 2D and 3D test cases: a step cloud, a cubic cloud, and a more realistic scenario including a 3D cloud field generated by a Large Eddy Simulation (LES) model and typical background aerosols. The commonly established benchmark results for 3D polarized radiative transfer are available at the IPRT website (http

  11. GMMIP (v1.0) contribution to CMIP6: Global Monsoons Model Inter-comparison Project

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Tianjun; Turner, Andrew G.; Kinter, James L.; Wang, Bin; Qian, Yun; Chen, Xiaolong; Wu, Bo; Wang, Bin; Liu, Bo; Zou, Liwei; He, Bian

    2016-10-10

    The Global Monsoons Model Inter-comparison Project (GMMIP) has been endorsed by the panel of Coupled Model Inter-comparison Project (CMIP) as one of the participating model inter-comparison projects (MIPs) in the sixth phase of CMIP (CMIP6). The focus of GMMIP is on monsoon climatology, variability, prediction and projection, which is relevant to four of the “Grand Challenges” proposed by the World Climate Research Programme. At present, 21 international modeling groups are committed to joining GMMIP. This overview paper introduces the motivation behind GMMIP and the scientific questions it intends to answer. Three tiers of experiments, of decreasing priority, are designed to examine (a) model skill in simulating the climatology and interannual-to-multidecadal variability of global monsoons forced by the sea surface temperature during historical climate period; (b) the roles of the Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation in driving variations of the global and regional monsoons; and (c) the effects of large orographic terrain on the establishment of the monsoons. The outputs of the CMIP6 Diagnostic, Evaluation and Characterization of Klima experiments (DECK), “historical” simulation and endorsed MIPs will also be used in the diagnostic analysis of GMMIP to give a comprehensive understanding of the roles played by different external forcings, potential improvements in the simulation of monsoon rainfall at high resolution and reproducibility at decadal timescales. The implementation of GMMIP will improve our understanding of the fundamental physics of changes in the global and regional monsoons over the past 140 years and ultimately benefit monsoons prediction and projection in the current century.

  12. The international coordination of climate model validation and intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Gates, W L [Lawrence Livermore National Lab. Livermore, CA (United States). Program for Climate Model Diagnosis and Intercomparison

    1996-12-31

    Climate modeling, whereby basic physical laws are used to integrate the physics and dynamics of climate into a consistent system, plays a key role in climate research and is the medium through. Depending upon the portion(s) of the climate system being considered, climate models range from those concerned only with the equilibrium globally-averaged surface temperature to those depicting the 3-dimensional time-dependent evolution of the coupled atmosphere, ocean, sea ice and land surface. Here only the latter class of models are considered, which are commonly known as general circulation models (or GCMs). (author)

  13. The international coordination of climate model validation and intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Gates, W.L. [Lawrence Livermore National Lab. Livermore, CA (United States). Program for Climate Model Diagnosis and Intercomparison

    1995-12-31

    Climate modeling, whereby basic physical laws are used to integrate the physics and dynamics of climate into a consistent system, plays a key role in climate research and is the medium through. Depending upon the portion(s) of the climate system being considered, climate models range from those concerned only with the equilibrium globally-averaged surface temperature to those depicting the 3-dimensional time-dependent evolution of the coupled atmosphere, ocean, sea ice and land surface. Here only the latter class of models are considered, which are commonly known as general circulation models (or GCMs). (author)

  14. Assessing Agricultural Risks of Climate Change in the 21st Century in a Global Gridded Crop Model Intercomparison

    Science.gov (United States)

    Rosenzweig, Cynthia E.; Elliott, Joshua; Deryng, Delphine; Ruane, Alex C.; Mueller, Christoph; Arneth, Almut; Boote, Kenneth J.; Folberth, Christian; Glotter, Michael; Khabarov, Nikolay

    2014-01-01

    Here we present the results from an intercomparison of multiple global gridded crop models (GGCMs) within the framework of the Agricultural Model Intercomparison and Improvement Project and the Inter-Sectoral Impacts Model Intercomparison Project. Results indicate strong negative effects of climate change, especially at higher levels of warming and at low latitudes; models that include explicit nitrogen stress project more severe impacts. Across seven GGCMs, five global climate models, and four representative concentration pathways, model agreement on direction of yield changes is found in many major agricultural regions at both low and high latitudes; however, reducing uncertainty in sign of response in mid-latitude regions remains a challenge. Uncertainties related to the representation of carbon dioxide, nitrogen, and high temperature effects demonstrated here show that further research is urgently needed to better understand effects of climate change on agricultural production and to devise targeted adaptation strategies.

  15. Airborne spread of foot-and-mouth disease - Model intercomparison

    DEFF Research Database (Denmark)

    Gloster, John; Jones, Andrew; Redington, Alison

    2010-01-01

    Foot-and-mouth disease virus (FMDV) spreads by direct contact between animals, by animal products (milk, meat and semen), by mechanical transfer on people or fomites and by the airborne route, with the relative importance of each mechanism depending on the particular outbreak characteristics....... Atmospheric dispersion models have been developed to assess airborne spread of FMDV in a number of countries, including the UK, Denmark, Australia, New Zealand, USA and Canada. These models were compared at a Workshop hosted by the Institute for Animal Health/Met Office in 2008. Each modeller was provided...... with data relating to the 1967 outbreak of FMD in Hampshire, UK, and asked to predict the spread of FMDV by the airborne route. A number of key issues emerged from the Workshop and subsequent modelling work: (1) in general all models predicted similar directions for livestock at risk, with much...

  16. Ice Sheet Model Intercomparison Project (ISMIP6) contribution to CMIP6

    Science.gov (United States)

    Nowicki, Sophie M.J.; Payne, Tony; Larour, Eric; Seroussi, Helene; Goelzer, Heiko; Lipscomb, William; Gregory, Jonathan; Abe-Ouchi, Ayako; Shepherd, Andrew

    2018-01-01

    Reducing the uncertainty in the past, present and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model Intercomparison Project – phase 6 (CMIP6) focusing on the Greenland and Antarctic Ice Sheets. In this paper, we describe the framework for ISMIP6 and its relationship to other activities within CMIP6. The ISMIP6 experimental design relies on CMIP6 climate models and includes, for the first time within CMIP, coupled ice sheet – climate models as well as standalone ice sheet models. To facilitate analysis of the multi-model ensemble and to generate a set of standard climate inputs for standalone ice sheet models, ISMIP6 defines a protocol for all variables related to ice sheets. ISMIP6 will provide a basis for investigating the feedbacks, impacts, and sea-level changes associated with dynamic ice sheets and for quantifying the uncertainty in ice-sheet-sourced global sea-level change. PMID:29697697

  17. Ice Sheet Model Intercomparison Project (ISMIP6) Contribution to CMIP6

    Science.gov (United States)

    Nowicki, Sophie M. J.; Payne, Tony; Larour, Eric; Seroussi, Helene; Goelzer, Heiko; Lipscomb, William; Gregory, Jonathan; Abe-Ouchi, Ayako; Shepherd, Andrew

    2016-01-01

    Reducing the uncertainty in the past, present, and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model Intercomparison Project phase 6 (CMIP6) focusing on the Greenland and Antarctic ice sheets. In this paper, we describe the framework for ISMIP6 and its relationship with other activities within CMIP6. The ISMIP6 experimental design relies on CMIP6 climate models and includes, for the first time within CMIP, coupled ice-sheetclimate models as well as standalone ice-sheet models. To facilitate analysis of the multi-model ensemble and to generate a set of standard climate inputs for standalone ice-sheet models, ISMIP6 defines a protocol for all variables related to ice sheets. ISMIP6 will provide a basis for investigating the feedbacks, impacts, and sea-level changes associated with dynamic ice sheets and for quantifying the uncertainty in ice-sheet-sourced global sea-level change.

  18. The Geoengineering Model Intercomparison Project (GeoMIP)

    KAUST Repository

    Kravitz, Ben; Robock, Alan; Boucher, Olivier; Schmidt, Hauke; Taylor, Karl E.; Stenchikov, Georgiy L.; Schulz, Michael

    2011-01-01

    To evaluate the effects of stratospheric geoengineering with sulphate aerosols, we propose standard forcing scenarios to be applied to multiple climate models to compare their results and determine the robustness of their responses. Thus far

  19. Historical and idealized climate model experiments: an EMIC intercomparison

    DEFF Research Database (Denmark)

    Eby, M.; Weaver, A. J.; Alexander, K.

    2012-01-01

    Both historical and idealized climate model experiments are performed with a variety of Earth System Models of Intermediate Complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE...... and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land-use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures...... the Medieval Climate Anomaly and the Little Ice Age estimated from paleoclimate reconstructions. This in turn could be a result of errors in the reconstructions of volcanic and/or solar radiative forcing used to drive the models or the incomplete representation of certain processes or variability within...

  20. Airborne spread of foot-and-mouth disease - model intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Gloster, J; Jones, A; Redington, A; Burgin, L; Sorensen, J H; Turner, R; Dillon, M; Hullinger, P; Simpson, M; Astrup, P; Garner, G; Stewart, P; D' Amours, R; Sellers, R; Paton, D

    2008-09-04

    Foot-and-mouth disease is a highly infectious vesicular disease of cloven-hoofed animals caused by foot-and-mouth disease virus. It spreads by direct contact between animals, by animal products (milk, meat and semen), by mechanical transfer on people or fomites and by the airborne route - with the relative importance of each mechanism depending on the particular outbreak characteristics. Over the years a number of workers have developed or adapted atmospheric dispersion models to assess the risk of foot-and-mouth disease virus spread through the air. Six of these models were compared at a workshop hosted by the Institute for Animal Health/Met Office during 2008. A number of key issues emerged from the workshop and subsequent modelling work: (1) in general all of the models predicted similar directions for 'at risk' livestock with much of the remaining differences strongly related to differences in the meteorological data used; (2) determination of an accurate sequence of events is highly important, especially if the meteorological conditions vary substantially during the virus emission period; and (3) differences in assumptions made about virus release, environmental fate, and subsequent infection can substantially modify the size and location of the downwind risk area. Close relationships have now been established between participants, which in the event of an outbreak of disease could be readily activated to supply advice or modelling support.

  1. Historical and idealized climate model experiments: an EMIC intercomparison

    DEFF Research Database (Denmark)

    Eby, M.; Weaver, A. J.; Alexander, K.

    2012-01-01

    Both historical and idealized climate model experiments are performed with a variety of Earth System Models of Intermediate Complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE......, are used to assess the contributions of different climate forcings to the overall climate and carbon cycle response. The response of surface air temperature is the linear sum of the individual forcings, while the carbon cycle response shows considerable synergy between land-use change and CO2... and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land-use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures...

  2. The Agricultural Model Intercomparison and Improvement Project (AgMIP): Protocols and Pilot Studies

    Science.gov (United States)

    Rosenzweig, C.; Jones, J. W.; Hatfield, J. L.; Ruane, A. C.; Boote, K. J.; Thorburn, P.; Antle, J. M.; Nelson, G. C.; Porter, C.; Janssen, S.; hide

    2012-01-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) is a major international effort linking the climate, crop, and economic modeling communities with cutting-edge information technology to produce improved crop and economic models and the next generation of climate impact projections for the agricultural sector. The goals of AgMIP are to improve substantially the characterization of world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. Analyses of the agricultural impacts of climate variability and change require a transdisciplinary effort to consistently link state-of-the-art climate scenarios to crop and economic models. Crop model outputs are aggregated as inputs to regional and global economic models to determine regional vulnerabilities, changes in comparative advantage, price effects, and potential adaptation strategies in the agricultural sector. Climate, Crop Modeling, Economics, and Information Technology Team Protocols are presented to guide coordinated climate, crop modeling, economics, and information technology research activities around the world, along with AgMIP Cross-Cutting Themes that address uncertainty, aggregation and scaling, and the development of Representative Agricultural Pathways (RAPs) to enable testing of climate change adaptations in the context of other regional and global trends. The organization of research activities by geographic region and specific crops is described, along with project milestones. Pilot results demonstrate AgMIP's role in assessing climate impacts with explicit representation of uncertainties in climate scenarios and simulations using crop and economic models. An intercomparison of wheat model simulations near Obregón, Mexico reveals inter-model differences in yield sensitivity to [CO2] with model uncertainty holding approximately steady as concentrations rise, while uncertainty related to choice of crop model increases with

  3. Design and results of the ice sheet model initialisation initMIP-Greenland: an ISMIP6 intercomparison

    Directory of Open Access Journals (Sweden)

    H. Goelzer

    2018-04-01

    Full Text Available Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6, which is the primary activity within the Coupled Model Intercomparison Project Phase 6 (CMIP6 focusing on the ice sheets. Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of (1 the initial present-day state of the ice sheet and (2 the response in two idealised forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without additional forcing and in response to a large perturbation (prescribed surface mass balance anomaly; they should not be interpreted as sea-level projections. We present and discuss results that highlight the diversity of data sets, boundary conditions, and initialisation techniques used in the community to generate initial states of the Greenland ice sheet. We find good agreement across the ensemble for the dynamic response to surface mass balance changes in areas where the simulated ice sheets overlap but differences arising from the initial size of the ice sheet. The model drift in the control experiment is reduced for models that participated in earlier intercomparison exercises.

  4. Design and results of the ice sheet model initialisation experiments initMIP-Greenland: an ISMIP6 intercomparison

    Science.gov (United States)

    Goelzer, Heiko; Nowicki, Sophie; Edwards, Tamsin; Beckley, Matthew; Abe-Ouchi, Ayako; Aschwanden, Andy; Calov, Reinhard; Gagliardini, Olivier; Gillet-Chaulet, Fabien; Golledge, Nicholas R.; Gregory, Jonathan; Greve, Ralf; Humbert, Angelika; Huybrechts, Philippe; Kennedy, Joseph H.; Larour, Eric; Lipscomb, William H.; Le clec'h, Sébastien; Lee, Victoria; Morlighem, Mathieu; Pattyn, Frank; Payne, Antony J.; Rodehacke, Christian; Rückamp, Martin; Saito, Fuyuki; Schlegel, Nicole; Seroussi, Helene; Shepherd, Andrew; Sun, Sainan; van de Wal, Roderik; Ziemen, Florian A.

    2018-04-01

    Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives) have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6), which is the primary activity within the Coupled Model Intercomparison Project Phase 6 (CMIP6) focusing on the ice sheets. Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of (1) the initial present-day state of the ice sheet and (2) the response in two idealised forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without additional forcing) and in response to a large perturbation (prescribed surface mass balance anomaly); they should not be interpreted as sea-level projections. We present and discuss results that highlight the diversity of data sets, boundary conditions, and initialisation techniques used in the community to generate initial states of the Greenland ice sheet. We find good agreement across the ensemble for the dynamic response to surface mass balance changes in areas where the simulated ice sheets overlap but differences arising from the initial size of the ice sheet. The model drift in the control experiment is reduced for models that participated in earlier intercomparison exercises.

  5. Looking beyond general metrics for model comparison - lessons from an international model intercomparison study

    Science.gov (United States)

    de Boer-Euser, Tanja; Bouaziz, Laurène; De Niel, Jan; Brauer, Claudia; Dewals, Benjamin; Drogue, Gilles; Fenicia, Fabrizio; Grelier, Benjamin; Nossent, Jiri; Pereira, Fernando; Savenije, Hubert; Thirel, Guillaume; Willems, Patrick

    2017-01-01

    International collaboration between research institutes and universities is a promising way to reach consensus on hydrological model development. Although model comparison studies are very valuable for international cooperation, they do often not lead to very clear new insights regarding the relevance of the modelled processes. We hypothesise that this is partly caused by model complexity and the comparison methods used, which focus too much on a good overall performance instead of focusing on a variety of specific events. In this study, we use an approach that focuses on the evaluation of specific events and characteristics. Eight international research groups calibrated their hourly model on the Ourthe catchment in Belgium and carried out a validation in time for the Ourthe catchment and a validation in space for nested and neighbouring catchments. The same protocol was followed for each model and an ensemble of best-performing parameter sets was selected. Although the models showed similar performances based on general metrics (i.e. the Nash-Sutcliffe efficiency), clear differences could be observed for specific events. We analysed the hydrographs of these specific events and conducted three types of statistical analyses on the entire time series: cumulative discharges, empirical extreme value distribution of the peak flows and flow duration curves for low flows. The results illustrate the relevance of including a very quick flow reservoir preceding the root zone storage to model peaks during low flows and including a slow reservoir in parallel with the fast reservoir to model the recession for the studied catchments. This intercomparison enhanced the understanding of the hydrological functioning of the catchment, in particular for low flows, and enabled to identify present knowledge gaps for other parts of the hydrograph. Above all, it helped to evaluate each model against a set of alternative models.

  6. EURADOS intercomparison exercise on Monte Carlo modelling of a medical linear accelerator.

    Science.gov (United States)

    Caccia, Barbara; Le Roy, Maïwenn; Blideanu, Valentin; Andenna, Claudio; Arun, Chairmadurai; Czarnecki, Damian; El Bardouni, Tarek; Gschwind, Régine; Huot, Nicolas; Martin, Eric; Zink, Klemens; Zoubair, Mariam; Price, Robert; de Carlan, Loïc

    2017-01-01

    In radiotherapy, Monte Carlo (MC) methods are considered a gold standard to calculate accurate dose distributions, particularly in heterogeneous tissues. EURADOS organized an international comparison with six participants applying different MC models to a real medical linear accelerator and to one homogeneous and four heterogeneous dosimetric phantoms. The aim of this exercise was to identify, by comparison of different MC models with a complete experimental dataset, critical aspects useful for MC users to build and calibrate a simulation and perform a dosimetric analysis. Results show on average a good agreement between simulated and experimental data. However, some significant differences have been observed especially in presence of heterogeneities. Moreover, the results are critically dependent on the different choices of the initial electron source parameters. This intercomparison allowed the participants to identify some critical issues in MC modelling of a medical linear accelerator. Therefore, the complete experimental dataset assembled for this intercomparison will be available to all the MC users, thus providing them an opportunity to build and calibrate a model for a real medical linear accelerator.

  7. Cloud radiative effects and changes simulated by the Coupled Model Intercomparison Project Phase 5 models

    Science.gov (United States)

    Shin, Sun-Hee; Kim, Ok-Yeon; Kim, Dongmin; Lee, Myong-In

    2017-07-01

    Using 32 CMIP5 (Coupled Model Intercomparison Project Phase 5) models, this study examines the veracity in the simulation of cloud amount and their radiative effects (CREs) in the historical run driven by observed external radiative forcing for 1850-2005, and their future changes in the RCP (Representative Concentration Pathway) 4.5 scenario runs for 2006-2100. Validation metrics for the historical run are designed to examine the accuracy in the representation of spatial patterns for climatological mean, and annual and interannual variations of clouds and CREs. The models show large spread in the simulation of cloud amounts, specifically in the low cloud amount. The observed relationship between cloud amount and the controlling large-scale environment are also reproduced diversely by various models. Based on the validation metrics, four models—ACCESS1.0, ACCESS1.3, HadGEM2-CC, and HadGEM2-ES—are selected as best models, and the average of the four models performs more skillfully than the multimodel ensemble average. All models project global-mean SST warming at the increase of the greenhouse gases, but the magnitude varies across the simulations between 1 and 2 K, which is largely attributable to the difference in the change of cloud amount and distribution. The models that simulate more SST warming show a greater increase in the net CRE due to reduced low cloud and increased incoming shortwave radiation, particularly over the regions of marine boundary layer in the subtropics. Selected best-performing models project a significant reduction in global-mean cloud amount of about -0.99% K-1 and net radiative warming of 0.46 W m-2 K-1, suggesting a role of positive feedback to global warming.

  8. The Carbon Dioxide Removal Model Intercomparison Project (CDRMIP: rationale and experimental protocol for CMIP6

    Directory of Open Access Journals (Sweden)

    D. P. Keller

    2018-03-01

    Full Text Available The recent IPCC reports state that continued anthropogenic greenhouse gas emissions are changing the climate, threatening severe, pervasive and irreversible impacts. Slow progress in emissions reduction to mitigate climate change is resulting in increased attention to what is called geoengineering, climate engineering, or climate intervention – deliberate interventions to counter climate change that seek to either modify the Earth's radiation budget or remove greenhouse gases such as CO2 from the atmosphere. When focused on CO2, the latter of these categories is called carbon dioxide removal (CDR. Future emission scenarios that stay well below 2 °C, and all emission scenarios that do not exceed 1.5 °C warming by the year 2100, require some form of CDR. At present, there is little consensus on the climate impacts and atmospheric CO2 reduction efficacy of the different types of proposed CDR. To address this need, the Carbon Dioxide Removal Model Intercomparison Project (or CDRMIP was initiated. This project brings together models of the Earth system in a common framework to explore the potential, impacts, and challenges of CDR. Here, we describe the first set of CDRMIP experiments, which are formally part of the 6th Coupled Model Intercomparison Project (CMIP6. These experiments are designed to address questions concerning CDR-induced climate reversibility, the response of the Earth system to direct atmospheric CO2 removal (direct air capture and storage, and the CDR potential and impacts of afforestation and reforestation, as well as ocean alkalinization.>

  9. The Carbon Dioxide Removal Model Intercomparison Project (CDRMIP): rationale and experimental protocol for CMIP6

    Science.gov (United States)

    Keller, David P.; Lenton, Andrew; Scott, Vivian; Vaughan, Naomi E.; Bauer, Nico; Ji, Duoying; Jones, Chris D.; Kravitz, Ben; Muri, Helene; Zickfeld, Kirsten

    2018-03-01

    The recent IPCC reports state that continued anthropogenic greenhouse gas emissions are changing the climate, threatening severe, pervasive and irreversible impacts. Slow progress in emissions reduction to mitigate climate change is resulting in increased attention to what is called geoengineering, climate engineering, or climate intervention - deliberate interventions to counter climate change that seek to either modify the Earth's radiation budget or remove greenhouse gases such as CO2 from the atmosphere. When focused on CO2, the latter of these categories is called carbon dioxide removal (CDR). Future emission scenarios that stay well below 2 °C, and all emission scenarios that do not exceed 1.5 °C warming by the year 2100, require some form of CDR. At present, there is little consensus on the climate impacts and atmospheric CO2 reduction efficacy of the different types of proposed CDR. To address this need, the Carbon Dioxide Removal Model Intercomparison Project (or CDRMIP) was initiated. This project brings together models of the Earth system in a common framework to explore the potential, impacts, and challenges of CDR. Here, we describe the first set of CDRMIP experiments, which are formally part of the 6th Coupled Model Intercomparison Project (CMIP6). These experiments are designed to address questions concerning CDR-induced climate reversibility, the response of the Earth system to direct atmospheric CO2 removal (direct air capture and storage), and the CDR potential and impacts of afforestation and reforestation, as well as ocean alkalinization.>

  10. The PSACOIN level 1B exercise: A probabilistic code intercomparison involving a four compartment biosphere model

    International Nuclear Information System (INIS)

    Klos, R.A.; Sinclair, J.E.; Torres, C.; Mobbs, S.F.; Galson, D.A.

    1991-01-01

    The probabilistic Systems Assessment Code (PSAC) User Group of the OECD Nuclear Energy Agency has organised a series of code intercomparison studies of relevance to the performance assessment of underground repositories for radioactive wastes - known collectively by the name PSACOIN. The latest of these to be undertaken is designated PSACOIN Level 1b, and the case specification provides a complete assessment model of the behaviour of radionuclides following release into the biosphere. PSACOIN Level 1b differs from other biosphere oriented intercomparison exercises in that individual dose is the end point of the calculations as opposed to any other intermediate quantity. The PSACOIN Level 1b case specification describes a simple source term which is used to simulate the release of activity to the biosphere from certain types of near surface waste repository, the transport of radionuclides through the biosphere and their eventual uptake by humankind. The biosphere sub model comprises 4 compartments representing top and deep soil layers, river water and river sediment. The transport of radionuclides between the physical compartments is described by ten transfer coefficients and doses to humankind arise from the simultaneous consumption of water, fish, meat, milk, and grain as well as from dust inhalation and external γ-irradiation. The parameters of the exposure pathway sub model are chosen to be representative of an individual living in a small agrarian community. (13 refs., 3 figs., 2 tabs.)

  11. Biogeochemical Protocols and Diagnostics for the CMIP6 Ocean Model Intercomparison Project (OMIP)

    Science.gov (United States)

    Orr, James C.; Najjar, Raymond G.; Aumont, Olivier; Bopp, Laurent; Bullister, John L.; Danabasoglu, Gokhan; Doney, Scott C.; Dunne, John P.; Dutay, Jean-Claude; Graven, Heather; hide

    2017-01-01

    The Ocean Model Intercomparison Project (OMIP) focuses on the physics and biogeochemistry of the ocean component of Earth system models participating in the sixth phase of the Coupled Model Intercomparison Project (CMIP6). OMIP aims to provide standard protocols and diagnostics for ocean models, while offering a forum to promote their common assessment and improvement. It also offers to compare solutions of the same ocean models when forced with reanalysis data (OMIP simulations) vs. when integrated within fully coupled Earth system models (CMIP6). Here we detail simulation protocols and diagnostics for OMIP's biogeochemical and inert chemical tracers. These passive-tracer simulations will be coupled to ocean circulation models, initialized with observational data or output from a model spin-up, and forced by repeating the 1948-2009 surface fluxes of heat, fresh water, and momentum. These so-called OMIP-BGC simulations include three inert chemical tracers (CFC-11, CFC-12, SF [subscript] 6) and biogeochemical tracers (e.g., dissolved inorganic carbon, carbon isotopes, alkalinity, nutrients, and oxygen). Modelers will use their preferred prognostic BGC model but should follow common guidelines for gas exchange and carbonate chemistry. Simulations include both natural and total carbon tracers. The required forced simulation (omip1) will be initialized with gridded observational climatologies. An optional forced simulation (omip1-spunup) will be initialized instead with BGC fields from a long model spin-up, preferably for 2000 years or more, and forced by repeating the same 62-year meteorological forcing. That optional run will also include abiotic tracers of total dissolved inorganic carbon and radiocarbon, CTabio and 14CTabio, to assess deep-ocean ventilation and distinguish the role of physics vs. biology. These simulations will be forced by observed atmospheric histories of the three inert gases and CO2 as well as carbon isotope ratios of CO2. OMIP-BGC simulation

  12. Biogeochemical protocols and diagnostics for the CMIP6 Ocean Model Intercomparison Project (OMIP)

    Science.gov (United States)

    Orr, James C.; Najjar, Raymond G.; Aumont, Olivier; Bopp, Laurent; Bullister, John L.; Danabasoglu, Gokhan; Doney, Scott C.; Dunne, John P.; Dutay, Jean-Claude; Graven, Heather; Griffies, Stephen M.; John, Jasmin G.; Joos, Fortunat; Levin, Ingeborg; Lindsay, Keith; Matear, Richard J.; McKinley, Galen A.; Mouchet, Anne; Oschlies, Andreas; Romanou, Anastasia; Schlitzer, Reiner; Tagliabue, Alessandro; Tanhua, Toste; Yool, Andrew

    2017-06-01

    The Ocean Model Intercomparison Project (OMIP) focuses on the physics and biogeochemistry of the ocean component of Earth system models participating in the sixth phase of the Coupled Model Intercomparison Project (CMIP6). OMIP aims to provide standard protocols and diagnostics for ocean models, while offering a forum to promote their common assessment and improvement. It also offers to compare solutions of the same ocean models when forced with reanalysis data (OMIP simulations) vs. when integrated within fully coupled Earth system models (CMIP6). Here we detail simulation protocols and diagnostics for OMIP's biogeochemical and inert chemical tracers. These passive-tracer simulations will be coupled to ocean circulation models, initialized with observational data or output from a model spin-up, and forced by repeating the 1948-2009 surface fluxes of heat, fresh water, and momentum. These so-called OMIP-BGC simulations include three inert chemical tracers (CFC-11, CFC-12, SF6) and biogeochemical tracers (e.g., dissolved inorganic carbon, carbon isotopes, alkalinity, nutrients, and oxygen). Modelers will use their preferred prognostic BGC model but should follow common guidelines for gas exchange and carbonate chemistry. Simulations include both natural and total carbon tracers. The required forced simulation (omip1) will be initialized with gridded observational climatologies. An optional forced simulation (omip1-spunup) will be initialized instead with BGC fields from a long model spin-up, preferably for 2000 years or more, and forced by repeating the same 62-year meteorological forcing. That optional run will also include abiotic tracers of total dissolved inorganic carbon and radiocarbon, CTabio and 14CTabio, to assess deep-ocean ventilation and distinguish the role of physics vs. biology. These simulations will be forced by observed atmospheric histories of the three inert gases and CO2 as well as carbon isotope ratios of CO2. OMIP-BGC simulation protocols are

  13. Biogeochemical protocols and diagnostics for the CMIP6 Ocean Model Intercomparison Project (OMIP

    Directory of Open Access Journals (Sweden)

    J. C. Orr

    2017-06-01

    Full Text Available The Ocean Model Intercomparison Project (OMIP focuses on the physics and biogeochemistry of the ocean component of Earth system models participating in the sixth phase of the Coupled Model Intercomparison Project (CMIP6. OMIP aims to provide standard protocols and diagnostics for ocean models, while offering a forum to promote their common assessment and improvement. It also offers to compare solutions of the same ocean models when forced with reanalysis data (OMIP simulations vs. when integrated within fully coupled Earth system models (CMIP6. Here we detail simulation protocols and diagnostics for OMIP's biogeochemical and inert chemical tracers. These passive-tracer simulations will be coupled to ocean circulation models, initialized with observational data or output from a model spin-up, and forced by repeating the 1948–2009 surface fluxes of heat, fresh water, and momentum. These so-called OMIP-BGC simulations include three inert chemical tracers (CFC-11, CFC-12, SF6 and biogeochemical tracers (e.g., dissolved inorganic carbon, carbon isotopes, alkalinity, nutrients, and oxygen. Modelers will use their preferred prognostic BGC model but should follow common guidelines for gas exchange and carbonate chemistry. Simulations include both natural and total carbon tracers. The required forced simulation (omip1 will be initialized with gridded observational climatologies. An optional forced simulation (omip1-spunup will be initialized instead with BGC fields from a long model spin-up, preferably for 2000 years or more, and forced by repeating the same 62-year meteorological forcing. That optional run will also include abiotic tracers of total dissolved inorganic carbon and radiocarbon, CTabio and 14CTabio, to assess deep-ocean ventilation and distinguish the role of physics vs. biology. These simulations will be forced by observed atmospheric histories of the three inert gases and CO2 as well as carbon isotope ratios of CO2. OMIP-BGC simulation

  14. DCMIP2016: a review of non-hydrostatic dynamical core design and intercomparison of participating models

    Science.gov (United States)

    Ullrich, Paul A.; Jablonowski, Christiane; Kent, James; Lauritzen, Peter H.; Nair, Ramachandran; Reed, Kevin A.; Zarzycki, Colin M.; Hall, David M.; Dazlich, Don; Heikes, Ross; Konor, Celal; Randall, David; Dubos, Thomas; Meurdesoif, Yann; Chen, Xi; Harris, Lucas; Kühnlein, Christian; Lee, Vivian; Qaddouri, Abdessamad; Girard, Claude; Giorgetta, Marco; Reinert, Daniel; Klemp, Joseph; Park, Sang-Hun; Skamarock, William; Miura, Hiroaki; Ohno, Tomoki; Yoshida, Ryuji; Walko, Robert; Reinecke, Alex; Viner, Kevin

    2017-12-01

    Atmospheric dynamical cores are a fundamental component of global atmospheric modeling systems and are responsible for capturing the dynamical behavior of the Earth's atmosphere via numerical integration of the Navier-Stokes equations. These systems have existed in one form or another for over half of a century, with the earliest discretizations having now evolved into a complex ecosystem of algorithms and computational strategies. In essence, no two dynamical cores are alike, and their individual successes suggest that no perfect model exists. To better understand modern dynamical cores, this paper aims to provide a comprehensive review of 11 non-hydrostatic dynamical cores, drawn from modeling centers and groups that participated in the 2016 Dynamical Core Model Intercomparison Project (DCMIP) workshop and summer school. This review includes a choice of model grid, variable placement, vertical coordinate, prognostic equations, temporal discretization, and the diffusion, stabilization, filters, and fixers employed by each system.

  15. DCMIP2016: a review of non-hydrostatic dynamical core design and intercomparison of participating models

    Directory of Open Access Journals (Sweden)

    P. A. Ullrich

    2017-12-01

    Full Text Available Atmospheric dynamical cores are a fundamental component of global atmospheric modeling systems and are responsible for capturing the dynamical behavior of the Earth's atmosphere via numerical integration of the Navier–Stokes equations. These systems have existed in one form or another for over half of a century, with the earliest discretizations having now evolved into a complex ecosystem of algorithms and computational strategies. In essence, no two dynamical cores are alike, and their individual successes suggest that no perfect model exists. To better understand modern dynamical cores, this paper aims to provide a comprehensive review of 11 non-hydrostatic dynamical cores, drawn from modeling centers and groups that participated in the 2016 Dynamical Core Model Intercomparison Project (DCMIP workshop and summer school. This review includes a choice of model grid, variable placement, vertical coordinate, prognostic equations, temporal discretization, and the diffusion, stabilization, filters, and fixers employed by each system.

  16. Theoretical intercomparison of multi-step direct reaction models and computational intercomparison of multi-step direct reaction models

    International Nuclear Information System (INIS)

    Koning, A.J.

    1992-08-01

    In recent years several statistical theories have been developed concerning multistep direct (MSD) nuclear reactions. In addition, dominant in applications is a whole class of semiclassical models that may be subsumed under the heading of 'generalized exciton models'. These are basically MSD-type extensions on top of compound-like concepts. In this report the relationship between their underlying statistical MSD-postulates is highlighted. A command framework is outlined that enables to generate the various MSD theories through assigning statistical properties to different parts of the nuclear Hamiltonian. Then it is shown that distinct forms of nuclear randomness are embodied in the mentioned theories. All these theories appear to be very similar at a qualitative level. In order to explain the high energy-tails and forward-peaked angular distribution typical for particles emitted in MSD reactions, it is imagined that the incident continuum particle stepwise looses its energy and direction in a sequence of collisions, thereby creating new particle-hole pairs in the target system. At each step emission may take place. The statistical aspect comes in because many continuum states are involved in the process. These are supposed to display chaotic behavior, the associated randomness assumption giving rise to important simplifications in the expression for MSD emission cross sections. This picture suggests that mentioned MSD models can be interpreted as a variant of essentially one and the same theory. However, this appears not to be the case. To show this usual MSD distinction within the composite reacting nucleus between the fast continuum particle and the residual interactions, the nucleons of the residual core are to be distinguished from those of the leading particle with the residual system. This distinction will turn out to be crucial to present analysis. 27 refs.; 5 figs.; 1 tab

  17. Interannual Tropical Rainfall Variability in General Circulation Model Simulations Associated with the Atmospheric Model Intercomparison Project.

    Science.gov (United States)

    Sperber, K. R.; Palmer, T. N.

    1996-11-01

    The interannual variability of rainfall over the Indian subcontinent, the African Sahel, and the Nordeste region of Brazil have been evaluated in 32 models for the period 1979-88 as part of the Atmospheric Model Intercomparison Project (AMIP). The interannual variations of Nordeste rainfall are the most readily captured, owing to the intimate link with Pacific and Atlantic sea surface temperatures. The precipitation variations over India and the Sahel are less well simulated. Additionally, an Indian monsoon wind shear index was calculated for each model. Evaluation of the interannual variability of a wind shear index over the summer monsoon region indicates that the models exhibit greater fidelity in capturing the large-scale dynamic fluctuations than the regional-scale rainfall variations. A rainfall/SST teleconnection quality control was used to objectively stratify model performance. Skill scores improved for those models that qualitatively simulated the observed rainfall/El Niño- Southern Oscillation SST correlation pattern. This subset of models also had a rainfall climatology that was in better agreement with observations, indicating a link between systematic model error and the ability to simulate interannual variations.A suite of six European Centre for Medium-Range Weather Forecasts (ECMWF) AMIP runs (differing only in their initial conditions) have also been examined. As observed, all-India rainfall was enhanced in 1988 relative to 1987 in each of these realizations. All-India rainfall variability during other years showed little or no predictability, possibly due to internal chaotic dynamics associated with intraseasonal monsoon fluctuations and/or unpredictable land surface process interactions. The interannual variations of Nordeste rainfall were best represented. The State University of New York at Albany/National Center for Atmospheric Research Genesis model was run in five initial condition realizations. In this model, the Nordeste rainfall

  18. The Cloud Feedback Model Intercomparison Project Observational Simulator Package: Version 2

    Science.gov (United States)

    Swales, Dustin J.; Pincus, Robert; Bodas-Salcedo, Alejandro

    2018-01-01

    The Cloud Feedback Model Intercomparison Project Observational Simulator Package (COSP) gathers together a collection of observation proxies or satellite simulators that translate model-simulated cloud properties to synthetic observations as would be obtained by a range of satellite observing systems. This paper introduces COSP2, an evolution focusing on more explicit and consistent separation between host model, coupling infrastructure, and individual observing proxies. Revisions also enhance flexibility by allowing for model-specific representation of sub-grid-scale cloudiness, provide greater clarity by clearly separating tasks, support greater use of shared code and data including shared inputs across simulators, and follow more uniform software standards to simplify implementation across a wide range of platforms. The complete package including a testing suite is freely available.

  19. The Cloud Feedback Model Intercomparison Project Observational Simulator Package: Version 2

    Directory of Open Access Journals (Sweden)

    D. J. Swales

    2018-01-01

    Full Text Available The Cloud Feedback Model Intercomparison Project Observational Simulator Package (COSP gathers together a collection of observation proxies or satellite simulators that translate model-simulated cloud properties to synthetic observations as would be obtained by a range of satellite observing systems. This paper introduces COSP2, an evolution focusing on more explicit and consistent separation between host model, coupling infrastructure, and individual observing proxies. Revisions also enhance flexibility by allowing for model-specific representation of sub-grid-scale cloudiness, provide greater clarity by clearly separating tasks, support greater use of shared code and data including shared inputs across simulators, and follow more uniform software standards to simplify implementation across a wide range of platforms. The complete package including a testing suite is freely available.

  20. Intercomparison and analyses of the climatology of the West African monsoon in the West African monsoon modeling and evaluation project (WAMME) first model intercomparison experiment

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongkang; Sales, Fernando De [University of California, Los Angeles, CA (United States); Lau, W.K.M.; Schubert, Siegfried D.; Wu, Man-Li C. [NASA, Goddard Space Flight Center, Greenbelt, MD (United States); Boone, Aaron [Centre National de Recherches Meteorologiques, Meteo-France Toulouse, Toulouse (France); Feng, Jinming [University of California, Los Angeles, CA (United States); Chinese Academy of Sciences, Institute of Atmospheric Physics, Beijing (China); Dirmeyer, Paul; Guo, Zhichang [Center for Ocean-Land-Atmosphere Interactions, Calverton, MD (United States); Kim, Kyu-Myong [University of Maryland Baltimore County, Baltimore, MD (United States); Kitoh, Akio [Meteorological Research Institute, Tsukuba (Japan); Kumar, Vadlamani [National Center for Environmental Prediction, Camp Springs, MD (United States); Wyle Information Systems, Gaithersburg, MD (United States); Poccard-Leclercq, Isabelle [Universite de Bourgogne, Centre de Recherches de Climatologie UMR5210 CNRS, Dijon (France); Mahowald, Natalie [Cornell University, Ithaca, NY (United States); Moufouma-Okia, Wilfran; Rowell, David P. [Met Office Hadley Centre, Exeter (United Kingdom); Pegion, Phillip [NASA, Goddard Space Flight Center, Greenbelt, MD (United States); National Center for Environmental Prediction, Camp Springs, MD (United States); Schemm, Jae; Thiaw, Wassila M. [National Center for Environmental Prediction, Camp Springs, MD (United States); Sealy, Andrea [The Caribbean Institute for Meteorology and Hydrology, St. James (Barbados); Vintzileos, Augustin [National Center for Environmental Prediction, Camp Springs, MD (United States); Science Applications International Corporation, Camp Springs, MD (United States); Williams, Steven F. [National Center for Atmospheric Research, Boulder, CO (United States)

    2010-07-15

    This paper briefly presents the West African monsoon (WAM) modeling and evaluation project (WAMME) and evaluates WAMME general circulation models' (GCM) performances in simulating variability of WAM precipitation, surface temperature, and major circulation features at seasonal and intraseasonal scales in the first WAMME experiment. The analyses indicate that models with specified sea surface temperature generally have reasonable simulations of the pattern of spatial distribution of WAM seasonal mean precipitation and surface temperature as well as the averaged zonal wind in latitude-height cross-section and low level circulation. But there are large differences among models in simulating spatial correlation, intensity, and variance of precipitation compared with observations. Furthermore, the majority of models fail to produce proper intensities of the African Easterly Jet (AEJ) and the tropical easterly jet. AMMA Land Surface Model Intercomparison Project (ALMIP) data are used to analyze the association between simulated surface processes and the WAM and to investigate the WAM mechanism. It has been identified that the spatial distributions of surface sensible heat flux, surface temperature, and moisture convergence are closely associated with the simulated spatial distribution of precipitation; while surface latent heat flux is closely associated with the AEJ and contributes to divergence in AEJ simulation. Common empirical orthogonal functions (CEOF) analysis is applied to characterize the WAM precipitation evolution and has identified a major WAM precipitation mode and two temperature modes (Sahara mode and Sahel mode). Results indicate that the WAMME models produce reasonable temporal evolutions of major CEOF modes but have deficiencies/uncertainties in producing variances explained by major modes. Furthermore, the CEOF analysis shows that WAM precipitation evolution is closely related to the enhanced Sahara mode and the weakened Sahel mode, supporting

  1. The Agricultural Model Intercomparison and Improvement Project (AgMIP): Progress and Preliminary Results

    Science.gov (United States)

    Rosenzweig, C.

    2011-12-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) is a distributed climate-scenario simulation exercise for historical model intercomparison and future climate change conditions with participation of multiple crop and agricultural trade modeling groups around the world. The goals of AgMIP are to improve substantially the characterization of risk of hunger and world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. Recent progress and the current status of AgMIP will be presented, highlighting three areas of activity: preliminary results from crop pilot studies, outcomes from regional workshops, and emerging scientific challenges. AgMIP crop modeling efforts are being led by pilot studies, which have been established for wheat, maize, rice, and sugarcane. These crop-specific initiatives have proven instrumental in testing and contributing to AgMIP protocols, as well as creating preliminary results for aggregation and input to agricultural trade models. Regional workshops are being held to encourage collaborations and set research activities in motion for key agricultural areas. The first of these workshops was hosted by Embrapa and UNICAMP and held in Campinas, Brazil. Outcomes from this meeting have informed crop modeling research activities within South America, AgMIP protocols, and future regional workshops. Several scientific challenges have emerged and are currently being addressed by AgMIP researchers. Areas of particular interest include geospatial weather generation, ensemble methods for climate scenarios and crop models, spatial aggregation of field-scale yields to regional and global production, and characterization of future changes in climate variability.

  2. The Agriculture Model Intercomparison and Improvement Project (AgMIP) (Invited)

    Science.gov (United States)

    Rosenzweig, C.

    2010-12-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) is a distributed climate-scenario simulation exercise for historical model intercomparison and future climate change conditions with participation of multiple crop and world agricultural trade modeling groups around the world. The goals of AgMIP are to improve substantially the characterization of risk of hunger and world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. Historical period results will spur model improvement and interaction among major modeling groups, while future period results will lead directly to tests of adaptation and mitigation strategies across a range of scales. AgMIP will consist of a multi-scale impact assessment utilizing the latest methods for climate and agricultural scenario generation. Scenarios and modeling protocols will be distributed on the web, and multi-model results will be collated and analyzed to ensure the widest possible coverage of agricultural crops and regions. AgMIP will place regional changes in agricultural production in a global context that reflects new trading opportunities, imbalances, and shortages in world markets resulting from climate change and other driving forces for food supply. Such projections are essential inputs from the Vulnerability, Impacts, and Adaptation (VIA) research community to the Intergovernmental Panel on Climate Change Fifth Assessment (AR5), now underway, and the UN Framework Convention on Climate Change. They will set the context for local-scale vulnerability and adaptation studies, supply test scenarios for national-scale development of trade policy instruments, provide critical information on changing supply and demand for water resources, and elucidate interactive effects of climate change and land use change. AgMIP will not only provide crucially-needed new global estimates of how climate change will affect food supply and hunger in the

  3. The GRENE-TEA model intercomparison project (GTMIP) Stage 1 forcing data set

    Science.gov (United States)

    Sueyoshi, T.; Saito, K.; Miyazaki, S.; Mori, J.; Ise, T.; Arakida, H.; Suzuki, R.; Sato, A.; Iijima, Y.; Yabuki, H.; Ikawa, H.; Ohta, T.; Kotani, A.; Hajima, T.; Sato, H.; Yamazaki, T.; Sugimoto, A.

    2016-01-01

    Here, the authors describe the construction of a forcing data set for land surface models (including both physical and biogeochemical models; LSMs) with eight meteorological variables for the 35-year period from 1979 to 2013. The data set is intended for use in a model intercomparison study, called GTMIP, which is a part of the Japanese-funded Arctic Climate Change Research Project. In order to prepare a set of site-fitted forcing data for LSMs with realistic yet continuous entries (i.e. without missing data), four observational sites across the pan-Arctic region (Fairbanks, Tiksi, Yakutsk, and Kevo) were selected to construct a blended data set using both global reanalysis and observational data. Marked improvements were found in the diurnal cycles of surface air temperature and humidity, wind speed, and precipitation. The data sets and participation in GTMIP are open to the scientific community (doi:10.17592/001.2015093001).

  4. Intercomparison exercises

    International Nuclear Information System (INIS)

    Arunachalam, J.

    2007-01-01

    Intercomparison exercises are vital to many a national programmes. These are only tools available with the laboratories to prove their competence to an international audience and also for the accrediting agencies to assess a laboratory

  5. An Intercomparison of ERS-Scat, AMSR-E Soil Moisture Observations with Model Simulations over France

    NARCIS (Netherlands)

    Rudiger, C.; Calvet, J.C.; Gruhier, C.; Holmes, T.R.H.; de Jeu, R.A.M.; Wagner, W.W.

    2009-01-01

    This paper presents a study undertaken in preparation of the work leading up to the assimilation of Soil Moisture and Ocean Salinity (SMOS) observations into the land surface model (LSM) Interaction Soil Biosphere Atmosphere (ISBA) at Météo-France. This study consists of an intercomparison

  6. Intercomparison of state-of-the-art models for wind energy resources with mesoscale models:

    Science.gov (United States)

    Olsen, Bjarke Tobias; Hahmann, Andrea N.; Sempreviva, Anna Maria; Badger, Jake; Joergensen, Hans E.

    2016-04-01

    vertical resolution, model parameterizations, surface roughness length) that could be used to group the various models and interpret the results of the intercomparison. 3. Main body abstract Twenty separate entries were received by the deadline of 31 March 2015. They included simulations done with various versions of the Weather Research and Forecast (WRF) model, but also of six other well-known mesoscale models. The various entries represent an excellent sample of the various models used in by the wind energy industry today. The analysis of the submitted time series included comparison to observations, summarized with well-known measures such as biases, RMSE, correlations, and of sector-wise statistics, e.g. frequency and Weibull A and k. The comparison also includes the observed and modeled temporal spectra. The various statistics were grouped as a function of the various models, their spatial resolution, forcing data, and the various integration methods. Many statistics have been computed and will be presented in addition to those shown in the Helsinki presentation. 4. Conclusions The analysis of the time series from twenty entries has shown to be an invaluable source of information about state of the art in wind modeling with mesoscale models. Biases between the simulated and observed wind speeds at hub heights (80-100 m AGL) from the various models are around ±1.0 m/s and fairly independent of the site and do not seem to be directly related to the model horizontal resolution used in the modeling. As probably expected, the wind speeds from the simulations using the various version of the WRF model cluster close to each other, especially in their description of the wind profile.

  7. Climate change impacts on tree ranges: model intercomparison facilitates understanding and quantification of uncertainty.

    Science.gov (United States)

    Cheaib, Alissar; Badeau, Vincent; Boe, Julien; Chuine, Isabelle; Delire, Christine; Dufrêne, Eric; François, Christophe; Gritti, Emmanuel S; Legay, Myriam; Pagé, Christian; Thuiller, Wilfried; Viovy, Nicolas; Leadley, Paul

    2012-06-01

    Model-based projections of shifts in tree species range due to climate change are becoming an important decision support tool for forest management. However, poorly evaluated sources of uncertainty require more scrutiny before relying heavily on models for decision-making. We evaluated uncertainty arising from differences in model formulations of tree response to climate change based on a rigorous intercomparison of projections of tree distributions in France. We compared eight models ranging from niche-based to process-based models. On average, models project large range contractions of temperate tree species in lowlands due to climate change. There was substantial disagreement between models for temperate broadleaf deciduous tree species, but differences in the capacity of models to account for rising CO(2) impacts explained much of the disagreement. There was good quantitative agreement among models concerning the range contractions for Scots pine. For the dominant Mediterranean tree species, Holm oak, all models foresee substantial range expansion. © 2012 Blackwell Publishing Ltd/CNRS.

  8. Intercomparison of the seasonal cycle of tropical surface stress in 17 AMIP atmospheric general circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Saji, N.H.; Goswami, B.N. [Indian Inst. of Sci., Bangalore (India). Centre for Atmos. and Oceanic Sci.

    1997-08-01

    The mean state of the tropical atmosphere is important as the nature of the coupling between the ocean and the atmosphere depends nonlinearly on the basic state of the coupled system. The simulation of the annual cycle of the tropical surface wind stress by 17 atmospheric general circulation models (AGCMs) is examined and intercompared. The models considered were part of the atmospheric model intercomparison project (AMIP) and were integrated with observed sea surface temperature (SST) for the decade 1979-1988. Several measures have been devised to intercompare the performance of the 17 models on global tropical as well as regional scales. Within the limits of observational uncertainties, the models under examination simulate realistic tropical area-averaged zonal and meridional annual mean stresses. This is a noteworthy improvement over older generation low resolution models which were noted for their simulation of surface stresses considerably weaker than the observations. The models also simulate realistic magnitudes of the spatial distribution of the annual mean surface stress field and are seen to reproduce realistically its observed spatial pattern. Similar features are observed in the simulations of the annual variance field. The models perform well over almost all the tropical regions apart from a few. Of these, the simulations over Somali are interesting. Over this region, the models are seen to underestimate the annual mean zonal and meridional stresses. There is also wide variance between the different models in simulating these quantities. 44 refs.

  9. Inter-comparison of dynamic models for radionuclide transfer to marine biota in a Fukushima accident scenario

    Energy Technology Data Exchange (ETDEWEB)

    Vives i Batlle, J.; Beresford, N. A.; Beaugelin-Seiller, K.; Bezhenar, R.; Brown, J.; Cheng, J. -J.; Ćujić, M.; Dragović, S.; Duffa, C.; Fiévet, B.; Hosseini, A.; Jung, K. T.; Kamboj, S.; Keum, D. -K.; Kryshev, A.; LePoire, D.; Maderich, V.; Min, B. -I.; Periáñez, R.; Sazykina, T.; Suh, K. -S.; Yu, C.; Wang, C.; Heling, R.

    2016-03-01

    We report an inter-comparison of eight models designed to predict the radiological exposure of radionuclides in marine biota. The models were required to simulate dynamically the uptake and turnover of radionuclides by marine organisms. Model predictions of radionuclide uptake and turnover using kinetic calculations based on biological half-life (TB1/2) and/or more complex metabolic modelling approaches were used to predict activity concentrations and, consequently, dose rates of 90Sr, 131I and 137Cs to fish, crustaceans, macroalgae and molluscs under circumstances where the water concentrations are changing with time. For comparison, the ERICA Tool, a model commonly used in environmental assessment, and which uses equilibrium concentration ratios, was also used. As input to the models we used hydrodynamic forecasts of water and sediment activity concentrations using a simulated scenario reflecting the Fukushima accident releases. Although model variability is important, the intercomparison gives logical results, in that the dynamic models predict consistently a pattern of delayed rise of activity concentration in biota and slow decline instead of the instantaneous equilibrium with the activity concentration in seawater predicted by the ERICA Tool. The differences between ERICA and the dynamic models increase the shorter the TB1/2 becomes; however, there is significant variability between models, underpinned by parameter and methodological differences between them. The need to validate the dynamic models used in this intercomparison has been highlighted, particularly in regards to optimisation of the model biokinetic parameters.

  10. The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, Brian C.; Tebaldi, Claudia; van Vuuren, Detlef P.; Eyring, Veronika; Friedlingstein, Pierre; Hurtt, George; Knutti, Reto; Kriegler, Elmar; Lamarque, Jean-Francois; Lowe, Jason; Meehl, Gerald A.; Moss, Richard; Riahi, Keywan; Sanderson, Benjamin M.

    2016-01-01

    Projections of future climate change play a fundamental role in improving understanding of the climate system as well as characterizing societal risks and response options. The Scenario Model Intercomparison Project (ScenarioMIP) is the primary activity within Phase 6 of the Coupled Model Intercomparison Project (CMIP6) that will provide multi-model climate projections based on alternative scenarios of future emissions and land use changes produced with integrated assessment models. In this paper, we describe ScenarioMIP's objectives, experimental design, and its relation to other activities within CMIP6. The ScenarioMIP design is one component of a larger scenario process that aims to facilitate a wide range of integrated studies across the climate science, integrated assessment modeling, and impacts, adaptation, and vulnerability communities, and will form an important part of the evidence base in the forthcoming Intergovernmental Panel on Climate Change (IPCC) assessments. At the same time, it will provide the basis for investigating a number of targeted science and policy questions that are especially relevant to scenario-based analysis, including the role of specific forcings such as land use and aerosols, the effect of a peak and decline in forcing, the consequences of scenarios that limit warming to below 2 °C, the relative contributions to uncertainty from scenarios, climate models, and internal variability, and long-term climate system outcomes beyond the 21st century. To serve this wide range of scientific communities and address these questions, a design has been identified consisting of eight alternative 21st century scenarios plus one large initial condition ensemble and a set of long-term extensions, divided into two tiers defined by relative priority. Some of these scenarios will also provide a basis for variants planned to be run in other CMIP6-Endorsed MIPs to investigate questions related to specific forcings. Harmonized, spatially

  11. A statistical intercomparison of temperature and precipitation predicted by four general circulation models with historical data

    International Nuclear Information System (INIS)

    Grotch, S.L.

    1991-01-01

    This study is a detailed intercomparison of the results produced by four general circulation models (GCMs) that have been used to estimate the climatic consequences of a doubling of the CO 2 concentration. Two variables, surface air temperature and precipitation, annually and seasonally averaged, are compared for both the current climate and for the predicted equilibrium changes after a doubling of the atmospheric CO 2 concentration. The major question considered here is: how well do the predictions from different GCMs agree with each other and with historical climatology over different areal extents, from the global scale down to the range of only several gridpoints? Although the models often agree well when estimating averages over large areas, substantial disagreements become apparent as the spatial scale is reduced. At scales below continental, the correlations observed between different model predictions are often very poor. The implications of this work for investigation of climatic impacts on a regional scale are profound. For these two important variables, at least, the poor agreement between model simulations of the current climate on the regional scale calls into question the ability of these models to quantitatively estimate future climatic change on anything approaching the scale of a few (< 10) gridpoints, which is essential if these results are to be used in meaningful resource-assessment studies. A stronger cooperative effort among the different modeling groups will be necessary to assure that we are getting better agreement for the right reasons, a prerequisite for improving confidence in model projections. 11 refs.; 10 figs

  12. Coupled Model Intercomparison Project 5 (CMIP5) simulations of climate following volcanic eruptions

    KAUST Repository

    Driscoll, Simon; Bozzo, Alessio; Gray, Lesley J.; Robock, Alan; Stenchikov, Georgiy L.

    2012-01-01

    The ability of the climate models submitted to the Coupled Model Intercomparison Project 5 (CMIP5) database to simulate the Northern Hemisphere winter climate following a large tropical volcanic eruption is assessed. When sulfate aerosols are produced by volcanic injections into the tropical stratosphere and spread by the stratospheric circulation, it not only causes globally averaged tropospheric cooling but also a localized heating in the lower stratosphere, which can cause major dynamical feedbacks. Observations show a lower stratospheric and surface response during the following one or two Northern Hemisphere (NH) winters, that resembles the positive phase of the North Atlantic Oscillation (NAO). Simulations from 13 CMIP5 models that represent tropical eruptions in the 19th and 20th century are examined, focusing on the large-scale regional impacts associated with the large-scale circulation during the NH winter season. The models generally fail to capture the NH dynamical response following eruptions. They do not sufficiently simulate the observed post-volcanic strengthened NH polar vortex, positive NAO, or NH Eurasian warming pattern, and they tend to overestimate the cooling in the tropical troposphere. The findings are confirmed by a superposed epoch analysis of the NAO index for each model. The study confirms previous similar evaluations and raises concern for the ability of current climate models to simulate the response of a major mode of global circulation variability to external forcings. This is also of concern for the accuracy of geoengineering modeling studies that assess the atmospheric response to stratosphere-injected particles.

  13. Coupled Model Intercomparison Project 5 (CMIP5) simulations of climate following volcanic eruptions

    KAUST Repository

    Driscoll, Simon

    2012-09-16

    The ability of the climate models submitted to the Coupled Model Intercomparison Project 5 (CMIP5) database to simulate the Northern Hemisphere winter climate following a large tropical volcanic eruption is assessed. When sulfate aerosols are produced by volcanic injections into the tropical stratosphere and spread by the stratospheric circulation, it not only causes globally averaged tropospheric cooling but also a localized heating in the lower stratosphere, which can cause major dynamical feedbacks. Observations show a lower stratospheric and surface response during the following one or two Northern Hemisphere (NH) winters, that resembles the positive phase of the North Atlantic Oscillation (NAO). Simulations from 13 CMIP5 models that represent tropical eruptions in the 19th and 20th century are examined, focusing on the large-scale regional impacts associated with the large-scale circulation during the NH winter season. The models generally fail to capture the NH dynamical response following eruptions. They do not sufficiently simulate the observed post-volcanic strengthened NH polar vortex, positive NAO, or NH Eurasian warming pattern, and they tend to overestimate the cooling in the tropical troposphere. The findings are confirmed by a superposed epoch analysis of the NAO index for each model. The study confirms previous similar evaluations and raises concern for the ability of current climate models to simulate the response of a major mode of global circulation variability to external forcings. This is also of concern for the accuracy of geoengineering modeling studies that assess the atmospheric response to stratosphere-injected particles.

  14. A statistical intercomparison of temperature and precipitation predicted by four general circulation models with historical data

    International Nuclear Information System (INIS)

    Grotch, S.L.

    1990-01-01

    This study is a detailed intercomparison of the results produced by four general circulation models (GCMs) that have been used to estimate the climatic consequences of a doubling of the CO 2 concentration. Two variables, surface air temperature and precipitation, annually and seasonally averaged, are compared for both the current climate and for the predicted equilibrium changes after a doubling of the atmospheric CO 2 concentration. The major question considered here is: how well do the predictions from different GCMs agree with each other and with historical climatology over different areal extents, from the global scale down to the range of only several gridpoints? Although the models often agree well when estimating averages over large areas, substantial disagreements become apparent as the spatial scale is reduced. At scales below continental, the correlations observed between different model predictions are often very poor. The implications of this work for investigation of climatic impacts on a regional scale are profound. For these two important variables, at least, the poor agreement between model simulations of the current climate on the regional scale calls into question the ability of these models to quantitatively estimate future climatic change on anything approaching the scale of a few (< 10) gridpoints, which is essential if these results are to be used in meaningful resource-assessment studies. A stronger cooperative effort among the different modeling groups will be necessary to assure that we are getting better agreement for the right reasons, a prerequisite for improving confidence in model projections

  15. Intercomparison and validation of snow albedo parameterization schemes in climate models

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, Christina A.; Winther, Jan-Gunnar [Norwegian Polar Institute, Tromsoe (Norway)

    2005-09-01

    Snow albedo is known to be crucial for heat exchange at high latitudes and high altitudes, and is also an important parameter in General Circulation Models (GCMs) because of its strong positive feedback properties. In this study, seven GCM snow albedo schemes and a multiple linear regression model were intercompared and validated against 59 years of in situ data from Svalbard, the French Alps and six stations in the former Soviet Union. For each site, the significant meteorological parameters for modeling the snow albedo were identified by constructing the 95% confidence intervals. The significant parameters were found to be: temperature, snow depth, positive degree day and a dummy of snow depth, and the multiple linear regression model was constructed to include these. Overall, the intercomparison showed that the modeled snow albedo varied more than the observed albedo for all models, and that the albedo was often underestimated. In addition, for several of the models, the snow albedo decreased at a faster rate or by a greater magnitude during the winter snow metamorphosis than the observed albedo. Both the temperature dependent schemes and the prognostic schemes showed shortcomings. (orig.)

  16. Ocean response to volcanic eruptions in Coupled Model Intercomparison Project 5 simulations

    KAUST Repository

    Ding, Yanni

    2014-09-01

    We examine the oceanic impact of large tropical volcanic eruptions as they appear in ensembles of historical simulations from eight Coupled Model Intercomparison Project Phase 5 models. These models show a response that includes lowering of global average sea surface temperature by 0.1–0.3 K, comparable to the observations. They show enhancement of Arctic ice cover in the years following major volcanic eruptions, with long-lived temperature anomalies extending to the middepth and deep ocean on decadal to centennial timescales. Regional ocean responses vary, although there is some consistent hemispheric asymmetry associated with the hemisphere in which the eruption occurs. Temperature decreases and salinity increases contribute to an increase in the density of surface water and an enhancement in the overturning circulation of the North Atlantic Ocean following these eruptions. The strength of this overturning increase varies considerably from model to model and is correlated with the background variability of overturning in each model. Any cause/effect relationship between eruptions and the phase of El Niño is weak.

  17. Intercomparison of terrestrial carbon fluxes and carbon use efficiency simulated by CMIP5 Earth System Models

    Science.gov (United States)

    Kim, Dongmin; Lee, Myong-In; Jeong, Su-Jong; Im, Jungho; Cha, Dong Hyun; Lee, Sanggyun

    2017-12-01

    This study compares historical simulations of the terrestrial carbon cycle produced by 10 Earth System Models (ESMs) that participated in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Using MODIS satellite estimates, this study validates the simulation of gross primary production (GPP), net primary production (NPP), and carbon use efficiency (CUE), which depend on plant function types (PFTs). The models show noticeable deficiencies compared to the MODIS data in the simulation of the spatial patterns of GPP and NPP and large differences among the simulations, although the multi-model ensemble (MME) mean provides a realistic global mean value and spatial distributions. The larger model spreads in GPP and NPP compared to those of surface temperature and precipitation suggest that the differences among simulations in terms of the terrestrial carbon cycle are largely due to uncertainties in the parameterization of terrestrial carbon fluxes by vegetation. The models also exhibit large spatial differences in their simulated CUE values and at locations where the dominant PFT changes, primarily due to differences in the parameterizations. While the MME-simulated CUE values show a strong dependence on surface temperatures, the observed CUE values from MODIS show greater complexity, as well as non-linear sensitivity. This leads to the overall underestimation of CUE using most of the PFTs incorporated into current ESMs. The results of this comparison suggest that more careful and extensive validation is needed to improve the terrestrial carbon cycle in terms of ecosystem-level processes.

  18. Cloud-resolving model intercomparison of an MC3E squall line case: Part I-Convective updrafts: CRM Intercomparison of a Squall Line

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Jiwen [Pacific Northwest National Laboratory, Richland Washington USA; Han, Bin [Pacific Northwest National Laboratory, Richland Washington USA; School of Atmospheric Sciences, Nanjing University, Nanjing China; Varble, Adam [Department of Atmospheric Sciences, University of Utah, Salt Lake City Utah USA; Morrison, Hugh [National Center for Atmospheric Research, Boulder Colorado USA; North, Kirk [Department of Atmospheric and Oceanic Sciences, McGill University, Montreal Quebec USA; Kollias, Pavlos [Department of Atmospheric and Oceanic Sciences, McGill University, Montreal Quebec USA; School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook New York USA; Chen, Baojun [School of Atmospheric Sciences, Nanjing University, Nanjing China; Dong, Xiquan [Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson Arizona USA; Giangrande, Scott E. [Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton New York USA; Khain, Alexander [The Institute of the Earth Science, The Hebrew University of Jerusalem, Jerusalem Israel; Lin, Yun [Department of Atmospheric Sciences, Texas A& M University, College Station Texas USA; Mansell, Edward [NOAA/OAR/National Severe Storms Laboratory, Norman Oklahoma USA; Milbrandt, Jason A. [Meteorological Research Division, Environment and Climate Change Canada, Dorval Canada; Stenz, Ronald [Department of Atmospheric Sciences, University of North Dakota, Grand Forks North Dakota USA; Thompson, Gregory [National Center for Atmospheric Research, Boulder Colorado USA; Wang, Yuan [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena California USA

    2017-09-06

    A constrained model intercomparison study of a mid-latitude mesoscale squall line is performed using the Weather Research & Forecasting (WRF) model at 1-km horizontal grid spacing with eight cloud microphysics schemes, to understand specific processes that lead to the large spread of simulated cloud and precipitation at cloud-resolving scales, with a focus of this paper on convective cores. Various observational data are employed to evaluate the baseline simulations. All simulations tend to produce a wider convective area than observed, but a much narrower stratiform area, with most bulk schemes overpredicting radar reflectivity. The magnitudes of the virtual potential temperature drop, pressure rise, and the peak wind speed associated with the passage of the gust front are significantly smaller compared with the observations, suggesting simulated cool pools are weaker. Simulations also overestimate the vertical velocity and Ze in convective cores as compared with observational retrievals. The modeled updraft velocity and precipitation have a significant spread across the eight schemes even in this strongly dynamically-driven system. The spread of updraft velocity is attributed to the combined effects of the low-level perturbation pressure gradient determined by cold pool intensity and buoyancy that is not necessarily well correlated to differences in latent heating among the simulations. Variability of updraft velocity between schemes is also related to differences in ice-related parameterizations, whereas precipitation variability increases in no-ice simulations because of scheme differences in collision-coalescence parameterizations.

  19. Intercomparison of reactive transport models applied to degradation of a concrete / clay interface

    International Nuclear Information System (INIS)

    Burnol, A.; Blanc, P.; Tournassat, C.; Lassin, A.; Gaucher, E.C.

    2005-01-01

    Full text of publication follows: Assuming a future disposal of spent nuclear fuel in deep geologic formation of Callovian- Oxfordian argillite in France, concrete will be used extensively to construct the disposal chambers in the host formation, and also as radioactive waste containment material. After being sealed, the repository will become saturated with interstitial waters from the Callovian-Oxfordian argillite, which will produce high pH solutions through interaction with the concrete. The aggressiveness of these alkaline solutions may weaken the clay's confinement properties (bentonite and argillite) with respect to long-lived radionuclides by change of the mineralogy. Conversely, the clayey formation with a high partial pressure of CO 2 represents an aggressive media for the concrete. The hydrogeological and chemical reactions of deep-underground systems are therefore intimately coupled and reactive transport models are increasingly used for performance assessment of nuclear waste disposal [1]. The main objective of this study is to present an intercomparison study using different reactive transport codes, where among PHREEQC1D [2], PHAST [3] and TOUGHREACT [4] applied to determine, in space and time, the extension of the alkaline perturbation and the associated degradation of concrete. The calculations were carried out after the definition of a complete mineralogy for both media. The experimental work made in the European Ecoclay II project [5] allowed a selection of reaction paths and of new phases for the thermodynamic database. Calculations were carried out over a simulated period of 100,000 years at different temperatures. Results of the different codes are compared and discussed. [1] De Windt L., Burnol A., Montarnal P., Van Der Lee.J., (2003) Intercomparison of reactive transport models applied to UO 2 oxidative dissolution and uranium migration., Journal of Contaminant Hydrology, 61, 1-4, 303-312; [2] Parkhurst D.L., Appelo C.A.J. (1999) - User

  20. Consistency of climate change projections from multiple global and regional model intercomparison projects

    Science.gov (United States)

    Fernández, J.; Frías, M. D.; Cabos, W. D.; Cofiño, A. S.; Domínguez, M.; Fita, L.; Gaertner, M. A.; García-Díez, M.; Gutiérrez, J. M.; Jiménez-Guerrero, P.; Liguori, G.; Montávez, J. P.; Romera, R.; Sánchez, E.

    2018-03-01

    We present an unprecedented ensemble of 196 future climate projections arising from different global and regional model intercomparison projects (MIPs): CMIP3, CMIP5, ENSEMBLES, ESCENA, EURO- and Med-CORDEX. This multi-MIP ensemble includes all regional climate model (RCM) projections publicly available to date, along with their driving global climate models (GCMs). We illustrate consistent and conflicting messages using continental Spain and the Balearic Islands as target region. The study considers near future (2021-2050) changes and their dependence on several uncertainty sources sampled in the multi-MIP ensemble: GCM, future scenario, internal variability, RCM, and spatial resolution. This initial work focuses on mean seasonal precipitation and temperature changes. The results show that the potential GCM-RCM combinations have been explored very unevenly, with favoured GCMs and large ensembles of a few RCMs that do not respond to any ensemble design. Therefore, the grand-ensemble is weighted towards a few models. The selection of a balanced, credible sub-ensemble is challenged in this study by illustrating several conflicting responses between the RCM and its driving GCM and among different RCMs. Sub-ensembles from different initiatives are dominated by different uncertainty sources, being the driving GCM the main contributor to uncertainty in the grand-ensemble. For this analysis of the near future changes, the emission scenario does not lead to a strong uncertainty. Despite the extra computational effort, for mean seasonal changes, the increase in resolution does not lead to important changes.

  1. The Palaeoclimate and Terrestrial Exoplanet Radiative Transfer Model Intercomparison Project (PALAEOTRIP: experimental design and protocols

    Directory of Open Access Journals (Sweden)

    C. Goldblatt

    2017-11-01

    Full Text Available Accurate radiative transfer calculation is fundamental to all climate modelling. For deep palaeoclimate, and increasingly terrestrial exoplanet climate science, this brings both the joy and the challenge of exotic atmospheric compositions. The challenge here is that most standard radiation codes for climate modelling have been developed for modern atmospheric conditions and may perform poorly away from these. The palaeoclimate or exoclimate modeller must either rely on these or use bespoke radiation codes, and in both cases rely on either blind faith or ad hoc testing of the code. In this paper, we describe the protocols for the Palaeoclimate and Terrestrial Exoplanet Radiative Transfer Model Intercomparison Project (PALAEOTRIP to systematically address this. This will compare as many radiation codes used for palaeoclimate or exoplanets as possible, with the aim of identifying the ranges of far-from-modern atmospheric compositions in which the codes perform well. This paper describes the experimental protocol and invites community participation in the project through 2017–2018.

  2. Intercomparison of model predictions of tritium concentrations in soil and foods following acute airborne HTO exposure

    International Nuclear Information System (INIS)

    Barry, P.J.; Watkins, B.M.; Belot, Y.; Davis, P.A.; Edlund, O.; Galeriu, D.; Raskob, W.; Russell, S.; Togawa, O.

    1998-01-01

    This paper describes the results of a model intercomparision exercise for predicting tritium transport through foodchains. Modellers were asked to assume that farmland was exposed for one hour to an average concentration in air of 10 4 MBq tritium m -3 . They were given the initial soil moisture content and 30 days of hourly averaged historical weather and asked to predict HTO and OBT concentrations in foods at selected times up to 30 days later when crops were assumed to be harvested. Two fumigations were postulated, one at 10.00 h (i.e., in day-light), and the other at 24.00 h (i.e., in darkness).Predicted environmental media concentrations after the daytime exposure agreed within an order of magnitude in most cases. Important sources of differences were variations in choices of numerical values for transport parameters. The different depths of soil layers used in the models appeared to make important contributions to differences in predictions for the given scenario. Following the night-time exposure, however, greater differences in predicted concentrations appeared. These arose largely because of different ways key processes were assumed to be affected by darkness. Uptake of HTO by vegetation and the rate it is converted to OBT were prominent amongst these processes. Further research, experimental data and modelling intercomparisons are required to resolve some of these issues. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. National Centers for Environmental Prediction-Department of Energy (NCEP-DOE) Atmospheric Model Intercomparison Project (AMIP)-II Reanalysis (Reanalysis-2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NCEP-DOE Atmospheric Model Intercomparison Project (AMIP-II) reanalysis is a follow-on project to the "50-year" (1948-present) NCEP-NCAR Reanalysis Project....

  4. Intercomparison and biokinetic model validation of radionuclide intake assessment. Report of a co-ordinated research project. 1996-1998

    International Nuclear Information System (INIS)

    1999-03-01

    This TECDOC presents the results of a Co-ordinated Research Project (CRP) on Intercomparison and Biokinetic Model Validation of Radionuclide Intake Assessment, including the conclusions of a Research Co-ordination Meeting held from 6 to 8 July 1998. The present CRP on Intercomparison and Biokinetic Model Validation of Radionuclide Intake Assessment is part of the activities of the IAEA's Occupational Protection programme. The objective of this programme is to promote an internationally harmonized approach for optimizing occupational radiation protection through: the development of guides, within the IAEA's activities for establishing standards for radiation protection, for restricting radiation exposures in the workplace and for applying current occupational radiation protection techniques; and the promotion of application of these guidelines

  5. Model Evaluation and Uncertainty in Agricultural Impacts Assessments: Results and Strategies from the Agricultural Model Intercomparison and Improvement Project (AgMIP)

    Science.gov (United States)

    Rosenzweig, C.; Hatfield, J.; Jones, J. W.; Ruane, A. C.

    2012-12-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) is an international effort to assess the state of global agricultural modeling and to understand climate impacts on the agricultural sector. AgMIP connects the climate science, crop modeling, and agricultural economic modeling communities to generate probabilistic projections of current and future climate impacts. The goals of AgMIP are to improve substantially the characterization of risk of hunger and world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. This presentation will describe the general approach of AgMIP, highlight AgMIP efforts to evaluate climate, crop, and economic models, and discuss AgMIP uncertainty assessments. Model evaluation efforts will be outlined using examples from various facets of AgMIP, including climate scenario generation, the wheat crop model intercomparison, and the global agricultural economics model intercomparison being led in collaboration with the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). Strategies developed to quantify uncertainty in each component of AgMIP, as well as the propagation of uncertainty through the climate-crop-economic modeling framework, will be detailed and preliminary uncertainty assessments that highlight crucial areas requiring improved models and data collection will be introduced.

  6. Assessment of the results of the 1998 Intercomparison of Individual Monitoring Systems under IAEA Model Project RLA/9/030

    International Nuclear Information System (INIS)

    Da Silva, Teogenes

    1999-01-01

    In this report the results of an intercomparison program within the framework of the IAEA model project RLA/9/030 are presented. This is the first phase of the study the main purpose was to establish a mechanism to identify and improve the current situation of each country as far as the performance of each individual monitoring system is concerned. This phase as was coordinated by Brazil through the Centro de Desenvolvimento da Tecnologia Nuclear that verified the performance of the participant laboratories. The following countries were invited to participate in the 1998 intercomparison: Bolivia, Costa Rica, Guatemala, Nicaragua, Panama, Jamaica and Paraguay. The performance of the laboratories was evaluated for dose assessment in terms of photon dose equivalent Hx

  7. Results of the 1999. Intercomparison of Individual Monitoring Systems under the IAEA Model Project RLA/9/030

    International Nuclear Information System (INIS)

    Da Silva, Teogenes

    2000-01-01

    In this report the results of the second phase of the intercomparison program within the framework of the IAEA model project RLA/9/030 are presented. In this second phase the objective was to evaluate the performance in terms of the quantity personal dose equivalent, Hp (10) for x and gamma radiation in the energy range form 20 KeV to 1.25 MeV. The main purpose of phase II should be the verification of the quality and reliability of the personnel monitoring system of each participating country. The Centro de Desenvolvimento da Tecnologia Nuclear was the reference laboratory that verified the performance of the participant laboratories. The following countries were invited to participate in the 1999 intercomparison: Bolivia, Colombia, Costa Rica, Dominican Republic, el Salvador, Guatemala, Jamaica, Nicaragua, Panama and Paraguay

  8. Introduction The Role of the Agricultural Model Intercomparison and Improvement Project

    Science.gov (United States)

    Rosenzweig, Cynthia; Hillel, Daniel

    2015-01-01

    Climate impacts on agriculture are of increasing concern in both the scientific and policy communities because of the need to ensure food security for a growing population. A special challenge is posed by the changes in the frequency and intensity of heat-waves, droughts, and episodic rainstorms already underway in many parts of the world. Changes in production are directly linked to such variations in temperature and precipitation during the growing season, and often to offseason changes in weather affecting soil-water storage and availability to crops. This is not an isolated problem but one of both global and regional importance, because of impacts on the livelihoods of smallholder farmers as well as consequences for the world food trade system. This two-part set the Agricultural Model Intercomparison and Improvement Project (AgMIP): Integrated Crop and Economic Assessments is the first to be entirely devoted to AgMIP (www.agmip.org). AgMIP is a major international research program focused on climate change and agriculture. The goal of the two parts is to advance the field by providing detailed information on new simulation techniques and assessments being conducted by this program. It presents information about new methods of global and regional integrated assessment, results from agricultural regions, and adaptation strategies for maintaining food security under changing climate conditions.

  9. Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM). I: Model intercomparison with current land use

    Science.gov (United States)

    Breuer, L.; Huisman, J.A.; Willems, P.; Bormann, H.; Bronstert, A.; Croke, B.F.W.; Frede, H.-G.; Graff, T.; Hubrechts, L.; Jakeman, A.J.; Kite, G.; Lanini, J.; Leavesley, G.; Lettenmaier, D.P.; Lindstrom, G.; Seibert, J.; Sivapalan, M.; Viney, N.R.

    2009-01-01

    This paper introduces the project on 'Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM)' that aims at investigating the envelope of predictions on changes in hydrological fluxes due to land use change. As part of a series of four papers, this paper outlines the motivation and setup of LUCHEM, and presents a model intercomparison for the present-day simulation results. Such an intercomparison provides a valuable basis to investigate the effects of different model structures on model predictions and paves the ground for the analysis of the performance of multi-model ensembles and the reliability of the scenario predictions in companion papers. In this study, we applied a set of 10 lumped, semi-lumped and fully distributed hydrological models that have been previously used in land use change studies to the low mountainous Dill catchment, Germany. Substantial differences in model performance were observed with Nash-Sutcliffe efficiencies ranging from 0.53 to 0.92. Differences in model performance were attributed to (1) model input data, (2) model calibration and (3) the physical basis of the models. The models were applied with two sets of input data: an original and a homogenized data set. This homogenization of precipitation, temperature and leaf area index was performed to reduce the variation between the models. Homogenization improved the comparability of model simulations and resulted in a reduced average bias, although some variation in model data input remained. The effect of the physical differences between models on the long-term water balance was mainly attributed to differences in how models represent evapotranspiration. Semi-lumped and lumped conceptual models slightly outperformed the fully distributed and physically based models. This was attributed to the automatic model calibration typically used for this type of models. Overall, however, we conclude that there was no superior model if several measures of model

  10. The impact of geoengineering on vegetation in experiment G1 of the Geoengineering Model Intercomparison Project

    Science.gov (United States)

    Irvine, Peter; Glienke, Susanne; Lawrence, Mark

    2015-04-01

    Solar Radiation Management (SRM) has been proposed as a means to partly counteract global warming. The Geoengineering Model Intercomparison Project (GeoMIP) simulated the climate consequences of a number of SRM techniques, but the effects on vegetation have not yet been thoroughly studied. Here, the vegetation response to the idealized GeoMIP G1 experiment is analyzed, in which a reduction of the solar constant counterbalances the radiative effects of quadrupled atmospheric CO2 concentrations; the results from eight fully coupled earth system models (ESMs) are included. For most models and regions, changes in net primary productivity (NPP) are dominated by the increase in CO2, via the CO2 fertilization effect. As SRM will lower temperatures, in high latitudes this will reverse gains in NPP from the lifting of temperature limitations. In low latitudes this cooling relative to the 4xCO2 simulation decreases plant respiration whilst having little effect on gross primary productivity, increasing NPP. Despite reductions in precipitation in most regions in response to SRM, runoff and NPP increase in many regions including those previously highlighted as potentially being at risk of drought under SRM. This is due to simultaneous reductions in evaporation and increases in water use efficiency by plants due to higher CO2 concentrations. The relative differences between models in the vegetation response are substantially larger than the differences in their climate responses. The largest differences between models are for those with and without a nitrogen-cycle, with a much smaller CO2 fertilization effect for the former. These results suggest that until key vegetation processes are integrated into ESM predictions, the vegetation response to SRM will remain highly uncertain.

  11. A protocol for the intercomparison of marine fishery and ecosystem models: Fish-MIP v1.0

    Directory of Open Access Journals (Sweden)

    D. P. Tittensor

    2018-04-01

    Full Text Available Model intercomparison studies in the climate and Earth sciences communities have been crucial to building credibility and coherence for future projections. They have quantified variability among models, spurred model development, contrasted within- and among-model uncertainty, assessed model fits to historical data, and provided ensemble projections of future change under specified scenarios. Given the speed and magnitude of anthropogenic change in the marine environment and the consequent effects on food security, biodiversity, marine industries, and society, the time is ripe for similar comparisons among models of fisheries and marine ecosystems. Here, we describe the Fisheries and Marine Ecosystem Model Intercomparison Project protocol version 1.0 (Fish-MIP v1.0, part of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP, which is a cross-sectoral network of climate impact modellers. Given the complexity of the marine ecosystem, this class of models has substantial heterogeneity of purpose, scope, theoretical underpinning, processes considered, parameterizations, resolution (grain size, and spatial extent. This heterogeneity reflects the lack of a unified understanding of the marine ecosystem and implies that the assemblage of all models is more likely to include a greater number of relevant processes than any single model. The current Fish-MIP protocol is designed to allow these heterogeneous models to be forced with common Earth System Model (ESM Coupled Model Intercomparison Project Phase 5 (CMIP5 outputs under prescribed scenarios for historic (from the 1950s and future (to 2100 time periods; it will be adapted to CMIP phase 6 (CMIP6 in future iterations. It also describes a standardized set of outputs for each participating Fish-MIP model to produce. This enables the broad characterization of differences between and uncertainties within models and projections when assessing climate and fisheries impacts on marine ecosystems

  12. A protocol for the intercomparison of marine fishery and ecosystem models: Fish-MIP v1.0

    Science.gov (United States)

    Tittensor, Derek P.; Eddy, Tyler D.; Lotze, Heike K.; Galbraith, Eric D.; Cheung, William; Barange, Manuel; Blanchard, Julia L.; Bopp, Laurent; Bryndum-Buchholz, Andrea; Büchner, Matthias; Bulman, Catherine; Carozza, David A.; Christensen, Villy; Coll, Marta; Dunne, John P.; Fernandes, Jose A.; Fulton, Elizabeth A.; Hobday, Alistair J.; Huber, Veronika; Jennings, Simon; Jones, Miranda; Lehodey, Patrick; Link, Jason S.; Mackinson, Steve; Maury, Olivier; Niiranen, Susa; Oliveros-Ramos, Ricardo; Roy, Tilla; Schewe, Jacob; Shin, Yunne-Jai; Silva, Tiago; Stock, Charles A.; Steenbeek, Jeroen; Underwood, Philip J.; Volkholz, Jan; Watson, James R.; Walker, Nicola D.

    2018-04-01

    Model intercomparison studies in the climate and Earth sciences communities have been crucial to building credibility and coherence for future projections. They have quantified variability among models, spurred model development, contrasted within- and among-model uncertainty, assessed model fits to historical data, and provided ensemble projections of future change under specified scenarios. Given the speed and magnitude of anthropogenic change in the marine environment and the consequent effects on food security, biodiversity, marine industries, and society, the time is ripe for similar comparisons among models of fisheries and marine ecosystems. Here, we describe the Fisheries and Marine Ecosystem Model Intercomparison Project protocol version 1.0 (Fish-MIP v1.0), part of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), which is a cross-sectoral network of climate impact modellers. Given the complexity of the marine ecosystem, this class of models has substantial heterogeneity of purpose, scope, theoretical underpinning, processes considered, parameterizations, resolution (grain size), and spatial extent. This heterogeneity reflects the lack of a unified understanding of the marine ecosystem and implies that the assemblage of all models is more likely to include a greater number of relevant processes than any single model. The current Fish-MIP protocol is designed to allow these heterogeneous models to be forced with common Earth System Model (ESM) Coupled Model Intercomparison Project Phase 5 (CMIP5) outputs under prescribed scenarios for historic (from the 1950s) and future (to 2100) time periods; it will be adapted to CMIP phase 6 (CMIP6) in future iterations. It also describes a standardized set of outputs for each participating Fish-MIP model to produce. This enables the broad characterization of differences between and uncertainties within models and projections when assessing climate and fisheries impacts on marine ecosystems and the

  13. New Results from the Geoengineering Model Intercomparison Project (GeoMIP)

    Science.gov (United States)

    Robock, A.; Kravitz, B.

    2013-12-01

    The Geoengineering Model Intercomparison Project (GeoMIP) was designed to determine robust climate system model responses to Solar Radiation Management (SRM). While mitigation (reducing greenhouse gases emissions) is the most effective way of reducing future climate change, SRM (the deliberate modification of incoming solar radiation) has been proposed as a means of temporarily alleviating some of the effects of global warming. For society to make informed decisions as to whether SRM should ever be implemented, information is needed on the benefits, risks, and side effects, and GeoMIP seeks to aid in that endeavor. GeoMIP has organized four standardized climate model simulations involving reduction of insolation or increased amounts of stratospheric sulfate aerosols to counteract increasing greenhouse gases. Thirteen comprehensive atmosphere-ocean general circulation models have participated in the project so far. GeoMIP is a 'CMIP Coordinated Experiment' as part of the Climate Model Intercomparison Project 5 (CMIP5) and has been endorsed by SPARC (Stratosphere-troposphere Processes And their Role in Climate). GeoMIP has held three international workshops and has produced a number of recent journal articles. GeoMIP has found that if increasing greenhouse gases could be counteracted with insolation reduction, the global average temperature could be kept constant, but global average precipitation would reduce, particularly in summer monsoon regions around the world. Temperature changes would also not be uniform. The tropics would cool, but high latitudes would warm, with continuing, but reduced sea ice and ice sheet melting. Temperature extremes would still increase, but not as much as without SRM. If SRM were halted all at once, there would be rapid temperature and precipitation increases at 5-10 times the rates from gradual global warming. SRM combined with CO2 fertilization would have small impacts on rice production in China, but would increase maize production

  14. WETCHIMP-WSL: intercomparison of wetland methane emissions models over West Siberia

    Directory of Open Access Journals (Sweden)

    T. J. Bohn

    2015-06-01

    Full Text Available Wetlands are the world's largest natural source of methane, a powerful greenhouse gas. The strong sensitivity of methane emissions to environmental factors such as soil temperature and moisture has led to concerns about potential positive feedbacks to climate change. This risk is particularly relevant at high latitudes, which have experienced pronounced warming and where thawing permafrost could potentially liberate large amounts of labile carbon over the next 100 years. However, global models disagree as to the magnitude and spatial distribution of emissions, due to uncertainties in wetland area and emissions per unit area and a scarcity of in situ observations. Recent intensive field campaigns across the West Siberian Lowland (WSL make this an ideal region over which to assess the performance of large-scale process-based wetland models in a high-latitude environment. Here we present the results of a follow-up to the Wetland and Wetland CH4 Intercomparison of Models Project (WETCHIMP, focused on the West Siberian Lowland (WETCHIMP-WSL. We assessed 21 models and 5 inversions over this domain in terms of total CH4 emissions, simulated wetland areas, and CH4 fluxes per unit wetland area and compared these results to an intensive in situ CH4 flux data set, several wetland maps, and two satellite surface water products. We found that (a despite the large scatter of individual estimates, 12-year mean estimates of annual total emissions over the WSL from forward models (5.34 ± 0.54 Tg CH4 yr−1, inversions (6.06 ± 1.22 Tg CH4 yr−1, and in situ observations (3.91 ± 1.29 Tg CH4 yr−1 largely agreed; (b forward models using surface water products alone to estimate wetland areas suffered from severe biases in CH4 emissions; (c the interannual time series of models that lacked either soil thermal physics appropriate to the high latitudes or realistic emissions from unsaturated peatlands tended to be dominated by a single environmental driver

  15. The Cloud Feedback Model Intercomparison Project (CFMIP) contribution to CMIP6.

    Science.gov (United States)

    Webb, Mark J.; Andrews, Timothy; Bodas-Salcedo, Alejandro; Bony, Sandrine; Bretherton, Christopher S.; Chadwick, Robin; Chepfer, Helene; Douville, Herve; Good, Peter; Kay, Jennifer E.; hide

    2017-01-01

    The primary objective of CFMIP is to inform future assessments of cloud feedbacks through improved understanding of cloud-climate feedback mechanisms and better evaluation of cloud processes and cloud feedbacks in climate models. However, the CFMIP approach is also increasingly being used to understand other aspects of climate change, and so a second objective has now been introduced, to improve understanding of circulation, regional-scale precipitation, and non-linear changes. CFMIP is supporting ongoing model inter-comparison activities by coordinating a hierarchy of targeted experiments for CMIP6, along with a set of cloud-related output diagnostics. CFMIP contributes primarily to addressing the CMIP6 questions 'How does the Earth system respond to forcing?' and 'What are the origins and consequences of systematic model biases?' and supports the activities of the WCRP Grand Challenge on Clouds, Circulation and Climate Sensitivity. A compact set of Tier 1 experiments is proposed for CMIP6 to address this question: (1) what are the physical mechanisms underlying the range of cloud feedbacks and cloud adjustments predicted by climate models, and which models have the most credible cloud feedbacks? Additional Tier 2 experiments are proposed to address the following questions. (2) Are cloud feedbacks consistent for climate cooling and warming, and if not, why? (3) How do cloud-radiative effects impact the structure, the strength and the variability of the general atmospheric circulation in present and future climates? (4) How do responses in the climate system due to changes in solar forcing differ from changes due to CO2, and is the response sensitive to the sign of the forcing? (5) To what extent is regional climate change per CO2 doubling state-dependent (non-linear), and why? (6) Are climate feedbacks during the 20th century different to those acting on long-term climate change and climate sensitivity? (7) How do regional climate responses (e.g. in precipitation

  16. North American Carbon Project (NACP) Regional Model-Model and Model-Data Intercomparison Project

    Science.gov (United States)

    Huntzinger, D. N.; Post, W. M.; Jacobson, A. R.; Cook, R. B.

    2009-05-01

    Available observations are localized and widely separated in both space and time, so we depend heavily on models to characterize, understand, and predict carbon fluxes at regional and global scales. The results from each model differ because they use different approaches (forward vs. inverse), modeling strategies (detailed process, statistical, observation based), process representation, boundary conditions, initial conditions, and driver data. To investigate these differences we conducted a model-model and model-data comparison using available forward ecosystem model and atmospheric inverse output, along with regional scale inventory data. Forward or "bottom-up" models typically estimate carbon fluxes through a set of physiological relationships, and are based on our current mechanistic understanding of how carbon is exchanged within ecosystems. Inverse or "top-down" analyses use measured atmospheric concentrations of CO2, coupled with an atmospheric transport model to infer surface flux distributions. Although bottom-up models do fairly well at reproducing measured fluxes (i.e., net ecosystem exchange) at a given location, they vary considerably in their estimates of carbon flux over regional or continental scales, suggesting difficulty in scaling mechanistic relationships to large areas and/or timescales. Conversely, top-down inverse models predict fluxes that are quantitatively consistent with atmospheric measurements, suggesting that they are capturing large scale variability in flux quite well, but offer limited insights into the processes controlling this variability and how fluxes vary at fine spatial scales. The analyses focused on identifying and quantifying spatial and temporal patterns of carbon fluxes among the models; quantifying across-model variability, as well as comparing simulated or estimated surface fluxes and biomass to observed values at regional to continental scales for the period 2000-2005. The analysis focused on the following three

  17. The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Overview and Description of Models, Simulations and Climate Diagnostics

    Science.gov (United States)

    Lamarque, J.-F.; Shindell, D. T.; Naik, V.; Plummer, D.; Josse, B.; Righi, M.; Rumbold, S. T.; Schulz, M.; Skeie, R. B.; Strode, S.; hide

    2013-01-01

    The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) consists of a series of time slice experiments targeting the long-term changes in atmospheric composition between 1850 and 2100, with the goal of documenting composition changes and the associated radiative forcing. In this overview paper, we introduce the ACCMIP activity, the various simulations performed (with a requested set of 14) and the associated model output. The 16 ACCMIP models have a wide range of horizontal and vertical resolutions, vertical extent, chemistry schemes and interaction with radiation and clouds. While anthropogenic and biomass burning emissions were specified for all time slices in the ACCMIP protocol, it is found that the natural emissions are responsible for a significant range across models, mostly in the case of ozone precursors. The analysis of selected present-day climate diagnostics (precipitation, temperature, specific humidity and zonal wind) reveals biases consistent with state-of-the-art climate models. The model-to- model comparison of changes in temperature, specific humidity and zonal wind between 1850 and 2000 and between 2000 and 2100 indicates mostly consistent results. However, models that are clear outliers are different enough from the other models to significantly affect their simulation of atmospheric chemistry.

  18. A systematic intercomparison of regional flood frequency analysis models in a simulation framework

    Science.gov (United States)

    Ganora, Daniele; Laio, Francesco; Claps, Pierluigi

    2015-04-01

    Regional frequency analysis (RFA) is a well-established methodology to provide an estimate of the flood frequency curve (or other discharge-related variables), based on the fundamental concept of substituting temporal information at a site (no data or short time series) by exploiting observations at other sites (spatial information). Different RFA paradigms exist, depending on the way the information is transferred to the site of interest. Despite the wide use of such methodology, a systematic comparison between these paradigms has not been performed. The aim of this study is to provide a framework wherein carrying out the intercomparison: we thus synthetically generate data through Monte Carlo simulations for a number of (virtual) stations, following a GEV parent distribution; different scenarios can be created to represent different spatial heterogeneity patterns by manipulating the parameters of the parent distribution at each station (e.g. with a linear variation in space of the shape parameter of the GEV). A special case is the homogeneous scenario where each station record is sampled from the same parent distribution. For each scenario and each simulation, different regional models are applied to evaluate the 200-year growth factor at each station. Results are than compared to the exact growth factor of each station, which is known in our virtual world. Considered regional approaches include: (i) a single growth curve for the whole region; (ii) a multiple-region model based on cluster analysis which search for an adequate number of homogeneous subregions; (iii) a Region-of-Influence model which defines a homogeneous subregion for each site; (iv) a spatially-smooth estimation procedure based on linear regressions.. A further benchmark model is the at-site estimate based on the analysis of the local record. A comprehensive analysis of the results of the simulations shows that, if the scenario is homogeneous (no spatial variability), all the regional approaches

  19. The Agricultural Model Intercomparison and Improvement Project: Phase I Activities by a Global Community of Science. Chapter 1

    Science.gov (United States)

    Rosenzweig, Cynthia E.; Jones, James W.; Hatfield, Jerry L.; Antle, John M.; Ruane, Alexander C.; Mutter, Carolyn Z.

    2015-01-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) was founded in 2010. Its mission is to improve substantially the characterization of world food security as affected by climate variability and change, and to enhance adaptation capacity in both developing and developed countries. The objectives of AgMIP are to: Incorporate state-of-the-art climate, crop/livestock, and agricultural economic model improvements into coordinated multi-model regional and global assessments of future climate impacts and adaptation and other key aspects of the food system. Utilize multiple models, scenarios, locations, crops/livestock, and participants to explore uncertainty and the impact of data and methodological choices. Collaborate with regional experts in agronomy, animal sciences, economics, and climate to build a strong basis for model applications, addressing key climate related questions and sustainable intensification farming systems. Improve scientific and adaptive capacity in modeling for major agricultural regions in the developing and developed world, with a focus on vulnerable regions. Improve agricultural data and enhance data-sharing based on their intercomparison and evaluation using best scientific practices. Develop modeling frameworks to identify and evaluate promising adaptation technologies and policies and to prioritize strategies.

  20. CityDelta: A model intercomparison study to explore the impact of emission reductions in European cities in 2010

    International Nuclear Information System (INIS)

    Cuvelier, C.; Thunis, P.; Vignati, E.; Vautard, R.; Hodzic, A.; Vautard, R.; Hodzic, A.; Amann, M.; Bessagnet, B.; Honore, C.; Rouil, L.; Bedogni, M.; Berkowicz, R.; Brandt, J.; Brocheton, F.; Peuch, V.H.; Builtjes, P.; Schaap, M.; Carnavale, C.; Volta, M.; Coppalle, A.; Denby, B.; Douros, J.; Moussiopoulos, N.; Graf, A.; Hellmuth, O.; Jonson, J.; Tarrason, L.; Wind, P.; Kerschbaumer, A.; Stern, R.; De Leeuw, F.; Minguzzi, E.; Pertot, C.; Pirovano, G.; Sauter, F.; White, L.; Zuber, A.

    2007-01-01

    This paper gives an overview of the set up, methodology and the obtained results of the CityDelta (phase 1 and 2) project. In the context of the Clean Air For Europe programme of the European Commission, the CityDelta project was designed to evaluate the impact of emission-reduction strategies on air quality at the European continental scale and in European cities. Ozone and particulate matter (PM) are the main components that have been studied. To achieve this goal, a model intercomparison study was organized with the participation of more than 20 modelling groups with a large number of modelling configurations. Two following main topics can be identified in the project. First, in order to evaluate their strengths and weaknesses, the participating models were evaluated against observations in a control year (1999). An accompanying paper will discuss in detail this evaluation aspect for four European cities. The second topic is the actual evaluation of the impact of emission reductions on levels of ozone and PM, with particular attention to the differences between large-scale and fine-scale models. An accompanying paper will discuss this point in detail. In this overview paper the main input to the intercomparison is described as well as the use of the ensemble approach. Finally, attention is given to the policy relevant issue on how to implement the urban air quality signal into large-scale air quality models through the use of functional relationships. (authors)

  1. A report on intercomparison studies of computer programs which respectively model: i) radionuclide migration ii) equilibrium chemistry of groundwater

    International Nuclear Information System (INIS)

    Broyd, T.W.; McD Grant, M.; Cross, J.E.

    1985-01-01

    This report describes two intercomparison studies of computer programs which respectively model: i) radionuclide migration ii) equilibrium chemistry of groundwaters. These studies have been performed by running a series of test cases with each program and comparing the various results obtained. The work forms a part of the CEC MIRAGE project (MIgration of RAdionuclides in the GEosphere) and has been jointly funded by the CEC and the United Kingdom Department of the Environment. Presentations of the material contained herein were given at plenary meetings of the MIRAGE project in Brussels in March, 1984 (migration) and March, 1985 (equilibrium chemistry) respectively

  2. The Land Use Model Intercomparison Project (LUMIP) contribution to CMIP6: rationale and experimental design

    Science.gov (United States)

    Lawrence, David M.; Hurtt, George C.; Arneth, Almut; Brovkin, Victor; Calvin, Kate V.; Jones, Andrew D.; Jones, Chris D.; Lawrence, Peter J.; de Noblet-Ducoudré, Nathalie; Pongratz, Julia; Seneviratne, Sonia I.; Shevliakova, Elena

    2016-09-01

    Human land-use activities have resulted in large changes to the Earth's surface, with resulting implications for climate. In the future, land-use activities are likely to expand and intensify further to meet growing demands for food, fiber, and energy. The Land Use Model Intercomparison Project (LUMIP) aims to further advance understanding of the impacts of land-use and land-cover change (LULCC) on climate, specifically addressing the following questions. (1) What are the effects of LULCC on climate and biogeochemical cycling (past-future)? (2) What are the impacts of land management on surface fluxes of carbon, water, and energy, and are there regional land-management strategies with the promise to help mitigate climate change? In addressing these questions, LUMIP will also address a range of more detailed science questions to get at process-level attribution, uncertainty, data requirements, and other related issues in more depth and sophistication than possible in a multi-model context to date. There will be particular focus on the separation and quantification of the effects on climate from LULCC relative to all forcings, separation of biogeochemical from biogeophysical effects of land use, the unique impacts of land-cover change vs. land-management change, modulation of land-use impact on climate by land-atmosphere coupling strength, and the extent to which impacts of enhanced CO2 concentrations on plant photosynthesis are modulated by past and future land use.LUMIP involves three major sets of science activities: (1) development of an updated and expanded historical and future land-use data set, (2) an experimental protocol for specific LUMIP experiments for CMIP6, and (3) definition of metrics and diagnostic protocols that quantify model performance, and related sensitivities, with respect to LULCC. In this paper, we describe LUMIP activity (2), i.e., the LUMIP simulations that will formally be part of CMIP6. These experiments are explicitly designed to be

  3. Inter-Comparison of Retrieved and Modelled Soil Moisture and Coherency of Remotely Sensed Hydrology Data

    Science.gov (United States)

    Kolassa, Jana; Aires, Filipe

    2013-04-01

    A neural network algorithm has been developed for the retrieval of Soil Moisture (SM) from global satellite observations. The algorithm estimates soil moisture from a synergy of passive and active microwave, infrared and visible satellite observations in order to capture the different SM variabilities that the individual sensors are sensitive to. The advantages and drawbacks of each satellite observation have been analysed and the information type and content carried by each observation have been determined. A global data set of monthly mean soil moisture for the 1993-2000 period has been computed with the neural network algorithm (Kolassa et al., in press, 2012). The resulting soil moisture retrieval product has then been used in an inter-comparison study including soil moisture from (1) the HTESSEL model (Balsamo et al., 2009), (2) the WACMOS satellite product (Liu et al., 2011), and (3) in situ measurements from the International Soil Moisture Network (Dorigo et al., 2011). The analysis showed that the satellite remote sensing products are well-suited to capture the spatial variability of the in situ data and even show the potential to improve the modelled soil moisture. Both satellite retrievals also display a good agreement with the temporal structures of the in situ data, however, HTESSEL appears to be more suitable for capturing the temporal variability (Kolassa et al., in press, 2012). The use of this type of neural network approach is currently being investigated as a retrieval option for the SMOS mission. Our soil moisture retrieval product has also been used in a coherence study with precipitation data from GPCP (Adler et al., 2003) and inundation estimates from GIEMS (Prigent et al., 2007). It was investigated on a global scale whether the three observation-based datasets are coherent with each other and show the expected behaviour. For most regions of the Earth, the datasets were consistent and the behaviour observed could be explained with the known

  4. Intercomparison I

    International Nuclear Information System (INIS)

    Cortes P, A.; Garcia D, O.; Becerril V, A.

    1997-01-01

    Assuming the importance that have the use of measurement procedures which yield consistent results with other laboratories it is necessary to participate in international intercomparisons. In this time, the Radioactive patterns laboratory (LPR) at Metrology Department of National Institute of Nuclear Research participated in the Quality Appraisement Program (QAP) which was organized by the Energy Department of the United States in march 1997. In this program soil samples, vegetables and contaminated air filters were distributed with different radioisotopes. This laboratory took part in the measurement and analysis of one of the air filters. This filter was contaminated with 12 radioisotopes, 7 β emissors, 4 α and γ emissors and a β pure emissor. The β - γ emissors were measured with a gamma spectrometer system with a Ge high purity detector. From the 7 activity measurements corresponding to the β, γ emissors were qualified as acceptable. In this work, the used equipment is described and the procedure followed is reported for the problem filter measurement as well as the obtained results. (Author)

  5. Evaluation and intercomparison of Ozone and PM10 simulations by several chemistry transport models over four European cities within the CityDelta project

    NARCIS (Netherlands)

    Vautard, R.; Builtjes, P.H.J.; Thunis, P.; Cuvelier, C.; Bedogni, M.; Bessagnet, B.; Honoré, C.; Moussiopoulos, N.; Pirovano, G.; Schaap, M.; Stern, R.; Tarrason, L.; Wind, P.

    2007-01-01

    The CityDelta project Cuvelier et al. [2006. CityDelta: a model intercomparison study to explore the impact of emission reductions in European cities in 2010. Atmospheric Environment] is designed to evaluate the air quality response of several emission abatement scenarios for 2010 at the scale of

  6. A multi-model intercomparison of halogenated very short-lived substances (TransCom-VSLS): linking oceanic emissions and tropospheric transport for a reconciled estimate of the stratospheric source gas injection of bromine

    OpenAIRE

    Hossaini, R.; Patra, P. K.; Leeson, A. A.; Krysztofiak, G.; Abraham, N. L.; Andrews, S. J.; Archibald, A. T.; Aschmann, J.; Atlas, E. L.; Belikov, D. A.; Bonisch, H.; Carpenter, L. J.; Dhomse, S.; Dorf, M.; Engel, A.

    2016-01-01

    The first concerted multi-model intercomparison of halogenated very short-lived substances (VSLS) has been performed, within the framework of the ongoing Atmospheric Tracer Transport Model Intercomparison Project (TransCom). Eleven global models or model variants participated (nine chemical transport models and two chemistry–climate models) by simulating the major natural bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2), over a 20-year period (1993–2012). Except f...

  7. MVL spatiotemporal analysis for model intercomparison in EPS: application to the DEMETER multi-model ensemble

    Science.gov (United States)

    Fernández, J.; Primo, C.; Cofiño, A. S.; Gutiérrez, J. M.; Rodríguez, M. A.

    2009-08-01

    In a recent paper, Gutiérrez et al. (Nonlinear Process Geophys 15(1):109-114, 2008) introduced a new characterization of spatiotemporal error growth—the so called mean-variance logarithmic (MVL) diagram—and applied it to study ensemble prediction systems (EPS); in particular, they analyzed single-model ensembles obtained by perturbing the initial conditions. In the present work, the MVL diagram is applied to multi-model ensembles analyzing also the effect of model formulation differences. To this aim, the MVL diagram is systematically applied to the multi-model ensemble produced in the EU-funded DEMETER project. It is shown that the shared building blocks (atmospheric and ocean components) impose similar dynamics among different models and, thus, contribute to poorly sampling the model formulation uncertainty. This dynamical similarity should be taken into account, at least as a pre-screening process, before applying any objective weighting method.

  8. Historical and idealized climate model experiments: an intercomparison of Earth system models of intermediate complexity

    DEFF Research Database (Denmark)

    Eby, M.; Weaver, A. J.; Alexander, K.

    2013-01-01

    Both historical and idealized climate model experiments are performed with a variety of Earth system models of intermediate complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE...... and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures, overall 20...

  9. Inter-comparison of Computer Codes for TRISO-based Fuel Micro-Modeling and Performance Assessment

    International Nuclear Information System (INIS)

    Boer, Brian; Keun Jo, Chang; Wu, Wen; Ougouag, Abderrafi M.; McEachren, Donald; Venneri, Francesco

    2010-01-01

    The Next Generation Nuclear Plant (NGNP), the Deep Burn Pebble Bed Reactor (DB-PBR) and the Deep Burn Prismatic Block Reactor (DB-PMR) are all based on fuels that use TRISO particles as their fundamental constituent. The TRISO particle properties include very high durability in radiation environments, hence the designs reliance on the TRISO to form the principal barrier to radioactive materials release. This durability forms the basis for the selection of this fuel type for applications such as Deep Bun (DB), which require exposures up to four times those expected for light water reactors. It follows that the study and prediction of the durability of TRISO particles must be carried as part of the safety and overall performance characterization of all the designs mentioned above. Such evaluations have been carried out independently by the performers of the DB project using independently developed codes. These codes, PASTA, PISA and COPA, incorporate models for stress analysis on the various layers of the TRISO particle (and of the intervening matrix material for some of them), model for fission products release and migration then accumulation within the SiC layer of the TRISO particle, just next to the layer, models for free oxygen and CO formation and migration to the same location, models for temperature field modeling within the various layers of the TRISO particle and models for the prediction of failure rates. All these models may be either internal to the code or external. This large number of models and the possibility of different constitutive data and model formulations and the possibility of a variety of solution techniques makes it highly unlikely that the model would give identical results in the modeling of identical situations. The purpose of this paper is to present the results of an inter-comparison between the codes and to identify areas of agreement and areas that need reconciliation. The inter-comparison has been carried out by the cooperating

  10. Photochemical modeling in California with two chemical mechanisms: model intercomparison and response to emission reductions.

    Science.gov (United States)

    Cai, Chenxia; Kelly, James T; Avise, Jeremy C; Kaduwela, Ajith P; Stockwell, William R

    2011-05-01

    An updated version of the Statewide Air Pollution Research Center (SAPRC) chemical mechanism (SAPRC07C) was implemented into the Community Multiscale Air Quality (CMAQ) version 4.6. CMAQ simulations using SAPRC07C and the previously released version, SAPRC99, were performed and compared for an episode during July-August, 2000. Ozone (O3) predictions of the SAPRC07C simulation are generally lower than those of the SAPRC99 simulation in the key areas of central and southern California, especially in areas where modeled concentrations are greater than the federal 8-hr O3 standard of 75 parts per billion (ppb) and/or when the volatile organic compound (VOC)/nitrogen oxides (NOx) ratio is less than 13. The relative changes of ozone production efficiency (OPE) against the VOC/NOx ratio at 46 sites indicate that the OPE is reduced in SAPRC07C compared with SAPRC99 at most sites by as much as approximately 22%. The SAPRC99 and SAPRC07C mechanisms respond similarly to 20% reductions in anthropogenic VOC emissions. The response of the mechanisms to 20% NOx emissions reductions can be grouped into three cases. In case 1, in which both mechanisms show a decrease in daily maximum 8-hr O3 concentration with decreasing NOx emissions, the O3 decrease in SAPRC07C is smaller. In case 2, in which both mechanisms show an increase in O3 with decreasing NOx emissions, the O3 increase is larger in SAPRC07C. In case 3, SAPRC07C simulates an increase in O3 in response to reduced NOx emissions whereas SAPRC99 simulates a decrease in O3 for the same region. As a result, the areas where NOx controls would be disbeneficial are spatially expanded in SAPRC07C. Although the results presented here are valuable for understanding differences in predictions and model response for SAPRC99 and SAPRC07C, the study did not evaluate the impact of mechanism differences in the context of the U.S. Environmental Protection Agency's guidance for using numerical models in demonstrating air quality attainment

  11. Assessing doses to terrestrial wildlife at a radioactive waste disposal site: inter-comparison of modelling approaches.

    Science.gov (United States)

    Johansen, M P; Barnett, C L; Beresford, N A; Brown, J E; Černe, M; Howard, B J; Kamboj, S; Keum, D-K; Smodiš, B; Twining, J R; Vandenhove, H; Vives i Batlle, J; Wood, M D; Yu, C

    2012-06-15

    Radiological doses to terrestrial wildlife were examined in this model inter-comparison study that emphasised factors causing variability in dose estimation. The study participants used varying modelling approaches and information sources to estimate dose rates and tissue concentrations for a range of biota types exposed to soil contamination at a shallow radionuclide waste burial site in Australia. Results indicated that the dominant factor causing variation in dose rate estimates (up to three orders of magnitude on mean total dose rates) was the soil-to-organism transfer of radionuclides that included variation in transfer parameter values as well as transfer calculation methods. Additional variation was associated with other modelling factors including: how participants conceptualised and modelled the exposure configurations (two orders of magnitude); which progeny to include with the parent radionuclide (typically less than one order of magnitude); and dose calculation parameters, including radiation weighting factors and dose conversion coefficients (typically less than one order of magnitude). Probabilistic approaches to model parameterisation were used to encompass and describe variable model parameters and outcomes. The study confirms the need for continued evaluation of the underlying mechanisms governing soil-to-organism transfer of radionuclides to improve estimation of dose rates to terrestrial wildlife. The exposure pathways and configurations available in most current codes are limited when considering instances where organisms access subsurface contamination through rooting, burrowing, or using different localised waste areas as part of their habitual routines. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  12. An Intercomparison of Model Predictions for an Urban Contamination Resulting from the Explosion of a Radiological Dispersal Device

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Won Tae; Jeong, Hyo Jun; Kim, Eun Han; Han, Moon Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-03-15

    The METRO-K is a model for a radiological dose assessment due to a radioactive contamination in the Korean urban environment. The model has been taken part in the Urban Remediation Working Group within the IAEA's (International Atomic Energy Agency) EMRAS (Environmental Modeling for Radiation Safety) program. The Working Croup designed for the intercomparison of radioactive contamination to be resulted from the explosion of a radiological dispersal device in a hypothetical city. This paper dealt intensively with a part among a lot of predictive results which had been performed in the EMRAS program. The predictive results of three different models (METRO-K, RESRAD-RDD, CPHR) were submitted to the Working Group. The gap of predictive results was due to the difference of mathematical modeling approaches, parameter values, understanding of assessors. Even if final results (for example, dose rates from contaminated surfaces which might affect to a receptor) are similar, the understanding on the contribution of contaminated surfaces showed a great difference. Judging from the authors, it is due to the lack of understanding and information on radioactive terrors as well as the social and cultural gaps which assessors have been experienced. Therefore, it can be known that the experience of assessors and their subjective judgements might be important factors to get reliable results. If the acquisition of a little additional information is possible, it was identified that the METRO-K might be a useful tool for decision support against contamination resulting from radioactive terrors by improving the existing model.

  13. An Intercomparison of Model Predictions for an Urban Contamination Resulting from the Explosion of a Radiological Dispersal Device

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Jeong, Hyo Jun; Kim, Eun Han; Han, Moon Hee

    2009-01-01

    The METRO-K is a model for a radiological dose assessment due to a radioactive contamination in the Korean urban environment. The model has been taken part in the Urban Remediation Working Group within the IAEA's (International Atomic Energy Agency) EMRAS (Environmental Modeling for Radiation Safety) program. The Working Croup designed for the intercomparison of radioactive contamination to be resulted from the explosion of a radiological dispersal device in a hypothetical city. This paper dealt intensively with a part among a lot of predictive results which had been performed in the EMRAS program. The predictive results of three different models (METRO-K, RESRAD-RDD, CPHR) were submitted to the Working Group. The gap of predictive results was due to the difference of mathematical modeling approaches, parameter values, understanding of assessors. Even if final results (for example, dose rates from contaminated surfaces which might affect to a receptor) are similar, the understanding on the contribution of contaminated surfaces showed a great difference. Judging from the authors, it is due to the lack of understanding and information on radioactive terrors as well as the social and cultural gaps which assessors have been experienced. Therefore, it can be known that the experience of assessors and their subjective judgements might be important factors to get reliable results. If the acquisition of a little additional information is possible, it was identified that the METRO-K might be a useful tool for decision support against contamination resulting from radioactive terrors by improving the existing model.

  14. Interpretation of complexometric titration data: An intercomparison of methods for estimating models of trace metal complexation by natural organic ligands

    NARCIS (Netherlands)

    Pižeta, I.; Sander, S.G.; Hudson, R.J.M.; Omanovic, D.; Baars, O.; Barbeau, K.A.; Buck, K.N.; Bundy, R.M.; Carrasco, G.; Croot, P.L.; Garnier, C.; Gerringa, L.J.A.; Gledhill, M.; Hirose, K.; Kondo, Y.; Laglera, L.M.; Nuester, J.; Rijkenberg, M.J.A.; Takeda, S.; Twining, B.S.; Wells, M.

    2015-01-01

    With the common goal of more accurately and consistently quantifying ambient concentrations of free metal ions and natural organic ligands in aquatic ecosystems, researchers from 15 laboratories that routinely analyze trace metal speciation participated in an intercomparison of statistical methods

  15. Assessing doses to terrestrial wildlife at a radioactive waste disposal site: Inter-comparison of modelling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, M.P., E-mail: mathew.johansen@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW, 2232 (Australia); Barnett, C.L., E-mail: clb@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster (United Kingdom); Beresford, N.A., E-mail: nab@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster (United Kingdom); Brown, J.E., E-mail: justin.brown@nrpa.no [Norwegian Radiation Protection Authority, Oesteraas (Norway); Cerne, M., E-mail: marko.cerne@ijs.si [Jozef Stefan Institute, Ljubljana (Slovenia); Howard, B.J., E-mail: bjho@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster (United Kingdom); Kamboj, S., E-mail: skamboj@anl.gov [Argonne National Laboratory, IL (United States); Keum, D.-K., E-mail: dkkeum@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Smodis, B. [Jozef Stefan Institute, Ljubljana (Slovenia); Twining, J.R., E-mail: jrt@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW, 2232 (Australia); Vandenhove, H., E-mail: hvandenh@sckcen.be [Belgian Nuclear Research Centre, Mol (Belgium); Vives i Batlle, J., E-mail: jvbatll@sckcen.be [Belgian Nuclear Research Centre, Mol (Belgium); Wood, M.D., E-mail: m.d.wood@salford.ac.uk [University of Salford, Manchester (United Kingdom); Yu, C., E-mail: cyu@anl.gov [Argonne National Laboratory, IL (United States)

    2012-06-15

    Radiological doses to terrestrial wildlife were examined in this model inter-comparison study that emphasised factors causing variability in dose estimation. The study participants used varying modelling approaches and information sources to estimate dose rates and tissue concentrations for a range of biota types exposed to soil contamination at a shallow radionuclide waste burial site in Australia. Results indicated that the dominant factor causing variation in dose rate estimates (up to three orders of magnitude on mean total dose rates) was the soil-to-organism transfer of radionuclides that included variation in transfer parameter values as well as transfer calculation methods. Additional variation was associated with other modelling factors including: how participants conceptualised and modelled the exposure configurations (two orders of magnitude); which progeny to include with the parent radionuclide (typically less than one order of magnitude); and dose calculation parameters, including radiation weighting factors and dose conversion coefficients (typically less than one order of magnitude). Probabilistic approaches to model parameterisation were used to encompass and describe variable model parameters and outcomes. The study confirms the need for continued evaluation of the underlying mechanisms governing soil-to-organism transfer of radionuclides to improve estimation of dose rates to terrestrial wildlife. The exposure pathways and configurations available in most current codes are limited when considering instances where organisms access subsurface contamination through rooting, burrowing, or using different localised waste areas as part of their habitual routines. - Highlights: Black-Right-Pointing-Pointer Assessment of modelled dose rates to terrestrial biota from radionuclides. Black-Right-Pointing-Pointer The substantial variation among current approaches is quantifiable. Black-Right-Pointing-Pointer The dominant variable was soil

  16. Forward Model Studies of Water Vapor Using Scanning Microwave Radiometers, Global Positioning System, and Radiosondes during the Cloudiness Intercomparison Experiment

    International Nuclear Information System (INIS)

    Mattioli, Vinia; Westwater, Ed R.; Gutman, S.; Morris, Victor R.

    2005-01-01

    Brightness temperatures computed from five absorption models and radiosonde observations were analyzed by comparing them with measurements from three microwave radiometers at 23.8 and 31.4 GHz. Data were obtained during the Cloudiness Inter-Comparison experiment at the U.S. Department of Energy's Atmospheric Radiation Measurement Program's (ARM) site in North-Central Oklahoma in 2003. The radiometers were calibrated using two procedures, the so-called instantaneous ?tipcal? method and an automatic self-calibration algorithm. Measurements from the radiometers were in agreement, with less than a 0.4-K difference during clear skies, when the instantaneous method was applied. Brightness temperatures from the radiometer and the radiosonde showed an agreement of less than 0.55 K when the most recent absorption models were considered. Precipitable water vapor (PWV) computed from the radiometers were also compared to the PWV derived from a Global Positioning System station that operates at the ARM site. The instruments agree to within 0.1 cm in PWV retrieval

  17. Downscale cascades in tracer transport test cases: an intercomparison of the dynamical cores in the Community Atmosphere Model CAM5

    Directory of Open Access Journals (Sweden)

    J. Kent

    2012-12-01

    Full Text Available The accurate modeling of cascades to unresolved scales is an important part of the tracer transport component of dynamical cores of weather and climate models. This paper aims to investigate the ability of the advection schemes in the National Center for Atmospheric Research's Community Atmosphere Model version 5 (CAM5 to model this cascade. In order to quantify the effects of the different advection schemes in CAM5, four two-dimensional tracer transport test cases are presented. Three of the tests stretch the tracer below the scale of coarse resolution grids to ensure the downscale cascade of tracer variance. These results are compared with a high resolution reference solution, which is simulated on a resolution fine enough to resolve the tracer during the test. The fourth test has two separate flow cells, and is designed so that any tracer in the western hemisphere should not pass into the eastern hemisphere. This is to test whether the diffusion in transport schemes, often in the form of explicit hyper-diffusion terms or implicit through monotonic limiters, contains unphysical mixing.

    An intercomparison of three of the dynamical cores of the National Center for Atmospheric Research's Community Atmosphere Model version 5 is performed. The results show that the finite-volume (CAM-FV and spectral element (CAM-SE dynamical cores model the downscale cascade of tracer variance better than the semi-Lagrangian transport scheme of the Eulerian spectral transform core (CAM-EUL. Each scheme tested produces unphysical mass in the eastern hemisphere of the separate cells test.

  18. A limited area model intercomparison on the 'Montserrat-2000' flash-flood event using statistical and deterministic methods

    Directory of Open Access Journals (Sweden)

    S. Mariani

    2005-01-01

    Full Text Available In the scope of the European project Hydroptimet, INTERREG IIIB-MEDOCC programme, limited area model (LAM intercomparison of intense events that produced many damages to people and territory is performed. As the comparison is limited to single case studies, the work is not meant to provide a measure of the different models' skill, but to identify the key model factors useful to give a good forecast on such a kind of meteorological phenomena. This work focuses on the Spanish flash-flood event, also known as 'Montserrat-2000' event. The study is performed using forecast data from seven operational LAMs, placed at partners' disposal via the Hydroptimet ftp site, and observed data from Catalonia rain gauge network. To improve the event analysis, satellite rainfall estimates have been also considered. For statistical evaluation of quantitative precipitation forecasts (QPFs, several non-parametric skill scores based on contingency tables have been used. Furthermore, for each model run it has been possible to identify Catalonia regions affected by misses and false alarms using contingency table elements. Moreover, the standard 'eyeball' analysis of forecast and observed precipitation fields has been supported by the use of a state-of-the-art diagnostic method, the contiguous rain area (CRA analysis. This method allows to quantify the spatial shift forecast error and to identify the error sources that affected each model forecasts. High-resolution modelling and domain size seem to have a key role for providing a skillful forecast. Further work is needed to support this statement, including verification using a wider observational data set.

  19. The Program for Climate Model Diagnosis and Intercomparison (PCMDI) Software Development: Applications, Infrastructure, and Middleware/Networks

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Dean N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-06-30

    The status of and future plans for the Program for Climate Model Diagnosis and Intercomparison (PCMDI) hinge on software that PCMDI is either currently distributing or plans to distribute to the climate community in the near future. These software products include standard conventions, national and international federated infrastructures, and community analysis and visualization tools. This report also mentions other secondary software not necessarily led by or developed at PCMDI to provide a complete picture of the overarching applications, infrastructures, and middleware/networks. Much of the software described anticipates the use of future technologies envisioned over the span of next year to 10 years. These technologies, together with the software, will be the catalyst required to address extreme-scale data warehousing, scalability issues, and service-level requirements for a diverse set of well-known projects essential for predicting climate change. These tools, unlike the previous static analysis tools of the past, will support the co-existence of many users in a productive, shared virtual environment. This advanced technological world driven by extreme-scale computing and the data it generates will increase scientists’ productivity, exploit national and international relationships, and push research to new levels of understanding.

  20. Inter-comparison of different models for estimating clear sky solar global radiation for the Negev region of Israel

    International Nuclear Information System (INIS)

    Ianetz, Amiran; Lyubansky, Vera; Setter, Ilan; Kriheli, Boris; Evseev, Efim G.; Kudish, Avraham I.

    2007-01-01

    Solar global radiation is a function of solar altitude, site altitude, albedo, atmospheric transparency and cloudiness, whereas solar global radiation on a clear day is defined such that it is a function of all the abovementioned parameters except cloudiness. Consequently, analysis of the relative magnitudes of solar global radiation and solar global radiation on a clear day provides a platform for studying the influence of cloudiness on solar global radiation. The Iqbal filter for determining the day type has been utilized to calculate the monthly average clear day solar global radiation at three sites in the Negev region of Israel. An inter-comparison between four models for estimating clear sky solar global radiation at the three sites was made. The relative accuracy of the four models was determined by comparing the monthly average daily clear sky solar global radiation to that determined using the Iqbal filter. The analysis was performed on databases consisting of measurements made during the time interval of January 1991 to December 2004. The monthly average daily clear sky solar global radiation determined by the Berlynd model was found to give the best agreement with that determined using the Iqbal filter. The Berlynd model was then utilized to calculate a daily clear day index, K c , which is defined as the ratio of the daily solar global radiation to the daily clear day solar global radiation. It is suggested that this index be used as an indication of the degree of cloudiness. Linear regression analysis was performed on the individual monthly databases for each site to determine the correlation between the daily clear day index and the daily clearness index, K T

  1. Understanding the Reach of Agricultural Impacts from Climate Extremes in the Agricultural Model Intercomparison and Improvement Project (AgMIP)

    Science.gov (United States)

    Ruane, A. C.

    2016-12-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) has been working since 2010 to build a modeling framework capable of representing the complexities of agriculture, its dependence on climate, and the many elements of society that depend on food systems. AgMIP's 30+ activities explore the interconnected nature of climate, crop, livestock, economics, food security, and nutrition, using common protocols to systematically evaluate the components of agricultural assessment and allow multi-model, multi-scale, and multi-method analysis of intertwining changes in socioeconomic development, environmental change, and technological adaptation. AgMIP is now launching Coordinated Global and Regional Assessments (CGRA) with a particular focus on unforeseen consequences of development strategies, interactions between global and local systems, and the resilience of agricultural systems to extreme climate events. Climate extremes shock the agricultural system through local, direct impacts (e.g., droughts, heat waves, floods, severe storms) and also through teleconnections propagated through international trade. As the climate changes, the nature of climate extremes affecting agriculture is also likely to change, leading to shifting intensity, duration, frequency, and geographic extents of extremes. AgMIP researchers are developing new scenario methodologies to represent near-term extreme droughts in a probabilistic manner, field experiments that impose heat wave conditions on crops, increased resolution to differentiate sub-national drought impacts, new behavioral functions that mimic the response of market actors faced with production shortfalls, analysis of impacts from simultaneous failures of multiple breadbasket regions, and more detailed mapping of food and socioeconomic indicators into food security and nutrition metrics that describe the human impact in diverse populations. Agricultural models illustrate the challenges facing agriculture, allowing

  2. Further AMBER and Ecolego Intercomparisons

    International Nuclear Information System (INIS)

    Maul, Philip; Robinson, Peter; Broed, Robert

    2004-01-01

    The AMBER compartmental modelling software is used by Quintessa in undertaking Performance Assessment (PA) calculations for SKI. SSI and NRPA are supporting the development of Ecolego which is based on the Matlab/Simulink general purpose modelling software for undertaking PA calculations. Intercomparison calculations using AMBER and Ecolego have been undertaken based on calculation cases considered in SKB's SR97 assessment. The reasons for undertaking such intercomparisons included: 1. to give confidence in the use of AMBER and Ecolego for whole system PA calculations for a deep repository; and 2. to provide SKI and SSI with an understanding of some of the technical issues raised by seeking to repeat the SR97 calculations with different models and software. Conclusions drawn from these intercomparisons included: 1. Both modelling packages successfully reproduced SKB's SR97 calculations for the near field, geosphere and biosphere. 2. AMBER and Ecolego calculations were typically in agreement to within one significant figure, but in several instances the SR97 documentation was not sufficiently clear to enable the implementation of the models in AMBER and Ecolego to be unambiguous. In order to gain more information on the comparisons between the two codes, additional intercomparisons have been undertaken using input data from the Vault Safety Case originally undertaken as part of an IAEA research project (ISAM). The comparisons between the AMBER and Ecolego calculations for the ISAM vault safety case have shown excellent agreement. Calculations at specified times generally agree to around three significant figures, and calculations of peak radionuclide fluxes and concentrations agree to two significant figures. This agreement is particularly good given the large number of model compartments and the inclusion of decay changes of up to six members. The most important situation where agreement may not be as good as that generally found is where radionuclides have been

  3. Host model uncertainties in aerosol radiative forcing estimates: results from the AeroCom Prescribed intercomparison study

    Directory of Open Access Journals (Sweden)

    P. Stier

    2013-03-01

    Full Text Available Simulated multi-model "diversity" in aerosol direct radiative forcing estimates is often perceived as a measure of aerosol uncertainty. However, current models used for aerosol radiative forcing calculations vary considerably in model components relevant for forcing calculations and the associated "host-model uncertainties" are generally convoluted with the actual aerosol uncertainty. In this AeroCom Prescribed intercomparison study we systematically isolate and quantify host model uncertainties on aerosol forcing experiments through prescription of identical aerosol radiative properties in twelve participating models. Even with prescribed aerosol radiative properties, simulated clear-sky and all-sky aerosol radiative forcings show significant diversity. For a purely scattering case with globally constant optical depth of 0.2, the global-mean all-sky top-of-atmosphere radiative forcing is −4.47 Wm−2 and the inter-model standard deviation is 0.55 Wm−2, corresponding to a relative standard deviation of 12%. For a case with partially absorbing aerosol with an aerosol optical depth of 0.2 and single scattering albedo of 0.8, the forcing changes to 1.04 Wm−2, and the standard deviation increases to 1.01 W−2, corresponding to a significant relative standard deviation of 97%. However, the top-of-atmosphere forcing variability owing to absorption (subtracting the scattering case from the case with scattering and absorption is low, with absolute (relative standard deviations of 0.45 Wm−2 (8% clear-sky and 0.62 Wm−2 (11% all-sky. Scaling the forcing standard deviation for a purely scattering case to match the sulfate radiative forcing in the AeroCom Direct Effect experiment demonstrates that host model uncertainties could explain about 36% of the overall sulfate forcing diversity of 0.11 Wm−2 in the AeroCom Direct Radiative Effect experiment. Host model errors in aerosol radiative forcing are largest in regions of uncertain host model

  4. Upper-soil moisture inter-comparison from SMOS's products and land surface models over the Iberian Peninsula

    Science.gov (United States)

    Polcher, Jan; Barella-Ortiz, Anaïs; Aires, Filipe; Balsamo, Gianpaolo; Gelati, Emiliano; Rodríguez-Fernández, Nemesio

    2015-04-01

    Soil moisture is a key state variable of the hydrological cycle. It conditions runoff, infiltration and evaporation over continental surfaces, and is key for forecasting droughts and floods. It plays thus an important role in surface-atmosphere interactions. Surface Soil Moisture (SSM) can be measured by in situ measurements, by satellite observations or modelled using land surface models. As a complementary tool, data assimilation can be used to combine both modelling and satellite observations. The work presented here is an inter-comparison of retrieved and modelled SSM data, for the 2010 - 2012 period, over the Iberian Peninsula. The region has been chosen because its vegetation cover is not very dense and includes strong contrasts in the rainfall regimes and thus a diversity of behaviours for SSM. Furthermore this semi-arid region is strongly dependent on a good management of its water resources. Satellite observations correspond to the Soil Moisture and Ocean Salinity (SMOS) retrievals: the L2 product from an optimal interpolation retrieval, and 3 other products using Neural Network retrievals with different input information: SMOS time indexes, purely SMOS data, or addition of the European Advanced Scaterometer (ASCAT) backscattering, and the Moderate-Resolution Imaging Spectrometer (MODIS) surface temperature information. The modelled soil moistures have been taken from the ORCHIDEE (ORganising Carbon and Hydrology In Dynamic EcosystEms) and the HTESSEL (Hydrology-Tiled ECMWF Scheme for Surface Exchanges over Land) land surface models. Both models are forced with the same atmospheric conditions (as part of the Earth2Observe FP7 project) over the period but they represent the surface soil moisture with very different degrees of complexity. ORCHIDEE has 5 levels in the top 5 centimetres of soil while in HTESSEL this variable is part of the top soil moisture level. The two types of SMOS retrievals are compared to the model outputs in their spatial and temporal

  5. Intercomparison of IPCC AR4 models with ERA-40 and NCEP/NCAR reanalysis within the AFRICA-CORDEX domain

    Science.gov (United States)

    León, M.; González, Y.; Díaz, J. P.; Expósito, F. J.; Pérez, J. C.; González, A.

    2012-04-01

    One of the most useful techniques to obtain regional climate projections along the XXI century is to run a mesoscale model driven by coarse input data (initial and boundaries conditions) obtained from Atmosphere-Ocean coupled Global Circulation Models (AOGCM). This is the dynamical downscaling approach. To correctly configure the dynamical downscaling approach it is necessary to choose the correct input dataset that project the climatic situation in a more accurate way and to establish a boundary to the errors in the results associated to these input data. In this study, we consider that the agreement of models with present observations is a way to assign confidence to the quality of a model. With this aim we intercompare the surface temperature of 21 IPCC AR4 runs models with the results from the reanalysis databases ERA40 and NCEP/NCAR in the CORDEX-AFRICA domain in the period 1961-2000. Thus, we have studied the seasonal cycles of the four decades of this period in addition to the probability density functions (PDFs) of the IPCC models. The statistical study allows us to classify the IPCC AR4 models according to their discrepancies with reanalysis data for the CORDEX domain. In general, the MRI CGCM 2.3.2 IPCC AR4 model presents the best fits compared with the reanalysis databases regarding to the correlation factor, root mean square (rms) and PDF skill score. For the intercomparison with ERA-40, the percentage of points with rms lower than 2°C is over 80%, for the four decades; with 89% of the points showing correlations coefficients larger than 0.80 and a 76 % of the data presents skill-scores values, based on the common areas of the PDFs, above a threshold of 0.7. Acknowledgements The authors acknowledge to the MEC (Ministry of Education and Science, Spain) for the next supports: projects CGL2007-66477-C02-02/CLI, CGL2008-04740/CLI, CGL2010-21366-C04-01 and UNLL08-3E-007.

  6. Intercomparison of four regional climate models for the German State of Saxonia

    Science.gov (United States)

    Kreienkamp, F.; Spekat, A.; Enke, W.

    2009-09-01

    Results from four regional climate models which focus on Central Europe are presented: CCLM, the climate version of the German Weather Service's Local Model - REMO, the regional dynamic model from the Max Planck Institute for Meteorology in Hamburg - STAR, the statistical model developed at the PIK Potsdam Institute and WETTREG, the statistic-dynamic model developed by the company CEC Potsdam. For the area of the German State of Saxonia a host of properties and indicators were analyzed aiming to show the models' abilities to reconstruct the current climate and compare climate model scenarios. These include a group of thermal indicators, such as the number of ice, frost, summer and hot days, the number of tropical nights; then there are hydrometeorological indicators such as the exceedance of low and high precipitation thresholds; humidity, cloudiness and wind indicators complement the array. A selection of them showing similarities and differences of the models investigated will be presented.

  7. Intercomparison of hydrological model structures and calibration approaches in climate scenario impact projections

    Science.gov (United States)

    Vansteenkiste, Thomas; Tavakoli, Mohsen; Ntegeka, Victor; De Smedt, Florimond; Batelaan, Okke; Pereira, Fernando; Willems, Patrick

    2014-11-01

    The objective of this paper is to investigate the effects of hydrological model structure and calibration on climate change impact results in hydrology. The uncertainty in the hydrological impact results is assessed by the relative change in runoff volumes and peak and low flow extremes from historical and future climate conditions. The effect of the hydrological model structure is examined through the use of five hydrological models with different spatial resolutions and process descriptions. These were applied to a medium sized catchment in Belgium. The models vary from the lumped conceptual NAM, PDM and VHM models over the intermediate detailed and distributed WetSpa model to the fully distributed MIKE SHE model. The latter model accounts for the 3D groundwater processes and interacts bi-directionally with a full hydrodynamic MIKE 11 river model. After careful and manual calibration of these models, accounting for the accuracy of the peak and low flow extremes and runoff subflows, and the changes in these extremes for changing rainfall conditions, the five models respond in a similar way to the climate scenarios over Belgium. Future projections on peak flows are highly uncertain with expected increases as well as decreases depending on the climate scenario. The projections on future low flows are more uniform; low flows decrease (up to 60%) for all models and for all climate scenarios. However, the uncertainties in the impact projections are high, mainly in the dry season. With respect to the model structural uncertainty, the PDM model simulates significantly higher runoff peak flows under future wet scenarios, which is explained by its specific model structure. For the low flow extremes, the MIKE SHE model projects significantly lower low flows in dry scenario conditions in comparison to the other models, probably due to its large difference in process descriptions for the groundwater component, the groundwater-river interactions. The effect of the model

  8. The Significance of Quality Assurance within Model Intercomparison Projects at the World Data Centre for Climate (WDCC)

    Science.gov (United States)

    Toussaint, F.; Hoeck, H.; Stockhause, M.; Lautenschlager, M.

    2014-12-01

    The classical goals of a quality assessment system in the data life cycle are (1) to encourage data creators to improve their quality assessment procedures to reach the next quality level and (2) enable data consumers to decide, whether a dataset has a quality that is sufficient for usage in the target application, i.e. to appraise the data usability for their own purpose.As the data volumes of projects and the interdisciplinarity of data usage grow, the need for homogeneous structure and standardised notation of data and metadata increases. This third aspect is especially valid for the data repositories, as they manage data through machine agents. So checks for homogeneity and consistency in early parts of the workflow become essential to cope with today's data volumes.Selected parts of the workflow in the model intercomparison project CMIP5 and the archival of the data for the interdiscipliary user community of the IPCC-DDC AR5 and the associated quality checks are reviewed. We compare data and metadata checks and relate different types of checks to their positions in the data life cycle.The project's data citation approach is included in the discussion, with focus on temporal aspects of the time necessary to comply with the project's requirements for formal data citations and the demand for the availability of such data citations.In order to make different quality assessments of projects comparable, WDCC developed a generic Quality Assessment System. Based on the self-assessment approach of a maturity matrix, an objective and uniform quality level system for all data at WDCC is derived which consists of five maturity quality levels.

  9. Results of the dosimetry intercomparison

    International Nuclear Information System (INIS)

    Dure, Elsa S.

    2000-07-01

    The appropriate way to verify the accuracy of the results of dose reported by the laboratories that offer lend personal dosimetry service is in the periodic participation of round of intercomparison dosimetry, undertaken by laboratories whose standards are trace (Secondary Laboratory). The Laboratory of External Personal Dosimetry of the CNEA-PY has participated in three rounds of intercomparison. The first two were organized in the framework of the Model Project RLA/9/030 RADIOLOGICAL WASTE SECURITY, and the irradiations were carried out in the Laboratory of Regional Calibration of the Center of Nuclear Technology Development, Belo Horizonte-Brazil (1998) and in the National Laboratory of Metrology of the ionizing radiations of the Institute of Radioprotection and Dosimetry, Rio de Janeiro-Brazil (1999). The third was organized by the IAEA and the irradiations were made in the Physikalisch-Technische Bundesanstalt PTB, Braunschweig - Federal Republic of Germany (1999-2000) [es

  10. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP

    Directory of Open Access Journals (Sweden)

    D. S. Stevenson

    2013-03-01

    Full Text Available Ozone (O3 from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP has been used to calculate tropospheric ozone radiative forcings (RFs. All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750 to present-day (2010 tropospheric ozone RF of 410 mW m−2. The model range of pre-industrial to present-day changes in O3 produces a spread (±1 standard deviation in RFs of ±17%. Three different radiation schemes were used – we find differences in RFs between schemes (for the same ozone fields of ±10%. Applying two different tropopause definitions gives differences in RFs of ±3%. Given additional (unquantified uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of ±30% for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44±12%, nitrogen oxides (31 ± 9%, carbon monoxide (15 ± 3% and non-methane volatile organic compounds (9 ± 2%; earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m−2 DU−1, a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m−2; relative to 1750 for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5 of 350, 420, 370 and 460 (in 2030, and 200, 300, 280 and 600 (in 2100. Models show some coherent responses of ozone to climate change

  11. An intercomparison of mesoscale models at simple sites for wind energy applications

    DEFF Research Database (Denmark)

    Olsen, Bjarke Tobias; Hahmann, Andrea N.; Sempreviva, Anna Maria

    2017-01-01

    of the output from 25 NWP models is presented for three sites in northern Europe characterized by simple terrain. The models are evaluated sing a number of statistical properties relevant to wind energy and verified with observations. On average the models have small wind speed biases offshore and aloft ( ... %) and larger biases closer to the surface over land (> 7 %). A similar pattern is detected for the inter-model spread. Strongly stable and strongly unstable atmospheric stability conditions are associated with larger wind speed errors. Strong indications are found that using a grid spacing larger than 3 km...... decreases the accuracy of the models, but we found no evidence that using a grid spacing smaller than 3 km is necessary for these simple sites. Applying the models to a simple wind energy offshore wind farm highlights the importance of capturing the correct distributions of wind speed and direction....

  12. Testing and intercomparison of model predictions of radionuclide migration from a hypothetical area source

    International Nuclear Information System (INIS)

    O'Brien, R.S.; Yu, C.; Zeevaert, T.; Olyslaegers, G.; Amado, V.; Setlow, L.W.; Waggitt, P.W.

    2008-01-01

    This work was carried out as part of the International Atomic Energy Agency's EMRAS program. One aim of the work was to develop scenarios for testing computer models designed for simulating radionuclide migration in the environment, and to use these scenarios for testing the models and comparing predictions from different models. This paper presents the results of the development and testing of a hypothetical area source of NORM waste/residue using two complex computer models and one screening model. There are significant differences in the methods used to model groundwater flow between the complex models. The hypothetical source was used because of its relative simplicity and because of difficulties encountered in finding comprehensive, well-validated data sets for real sites. The source consisted of a simple repository of uniform thickness, with 1 Bq g -1 of uranium-238 ( 238 U) (in secular equilibrium with its decay products) distributed uniformly throughout the waste. These approximate real situations, such as engineered repositories, waste rock piles, tailings piles and landfills. Specification of the site also included the physical layout, vertical stratigraphic details, soil type for each layer of material, precipitation and runoff details, groundwater flow parameters, and meteorological data. Calculations were carried out with and without a cover layer of clean soil above the waste, for people working and living at different locations relative to the waste. The predictions of the two complex models showed several differences which need more detailed examination. The scenario is available for testing by other modelers. It can also be used as a planning tool for remediation work or for repository design, by changing the scenario parameters and running the models for a range of different inputs. Further development will include applying models to real scenarios and integrating environmental impact assessment methods with the safety assessment tools currently

  13. Intercomparison of single-column models for GABLS3: preliminary results

    NARCIS (Netherlands)

    Bosveld, F.C.; Bruijn, de E.I.F.; Holtslag, A.A.M.

    2008-01-01

    The GEWEX Atmospheric Boundary-Layer Study (GABLS) focus on the representation of stable boundary layers in atmospheric models (Holtslag, 2006). One of the main goals of GABLS is to provide a mondial platform for the atmospheric boundary layer research community through the organisation of model

  14. Spatio-temporal characteristics of Agulhas leakage: a model inter-comparison study

    CSIR Research Space (South Africa)

    Holton, L

    2016-05-01

    Full Text Available and thermohaline structure at the Good Hope line, a transect to the south west of the southern tip of Africa , is used to identify features that are robust regardless of the model used and takes into account the thermohaline biases of each model. When determined...

  15. Intercomparison of the community multiscale air quality model and CALGRID using process analysis.

    Science.gov (United States)

    O'Neill, Susan M; Lamb, Brian K

    2005-08-01

    This study was designed to examine the similarities and differences between two advanced photochemical air quality modeling systems: EPA Models-3/CMAQ and CALGRID/CALMET. Both modeling systems were applied to an ozone episode that occurred along the I-5 urban corridor in western Washington and Oregon during July 11-14, 1996. Both models employed the same modeling domain and used the same detailed gridded emission inventory. The CMAQ model was run using both the CB-IV and RADM2 chemical mechanisms, while CALGRID was used with the SAPRC-97 chemical mechanism. Outputfrom the Mesoscale Meteorological Model (MM5) employed with observational nudging was used in both models. The two modeling systems, representing three chemical mechanisms and two sets of meteorological inputs, were evaluated in terms of statistical performance measures for both 1- and 8-h average observed ozone concentrations. The results showed that the different versions of the systems were more similar than different, and all versions performed well in the Portland region and downwind of Seattle but performed poorly in the more rural region north of Seattle. Improving the meteorological input into the CALGRID/CALMET system with planetary boundary layer (PBL) parameters from the Models-3/CMAQ meteorology preprocessor (MCIP) improved the performance of the CALGRID/CALMET system. The 8-h ensemble case was often the best performer of all the cases indicating that the models perform better over longer analysis periods. The 1-h ensemble case, derived from all runs, was not necessarily an improvement over the five individual cases, but the standard deviation about the mean provided a measure of overall modeling uncertainty. Process analysis was applied to examine the contribution of the individual processes to the species conservation equation. The process analysis results indicated that the two modeling systems arrive at similar solutions by very different means. Transport rates are faster and exhibit

  16. Forecasting the northern African dust outbreak towards Europe in April 2011: a model intercomparison

    Directory of Open Access Journals (Sweden)

    N. Huneeus

    2016-04-01

    Full Text Available In the framework of the World Meteorological Organisation's Sand and Dust Storm Warning Advisory and Assessment System, we evaluated the predictions of five state-of-the-art dust forecast models during an intense Saharan dust outbreak affecting western and northern Europe in April 2011. We assessed the capacity of the models to predict the evolution of the dust cloud with lead times of up to 72 h using observations of aerosol optical depth (AOD from the AErosol RObotic NETwork (AERONET and the Moderate Resolution Imaging Spectroradiometer (MODIS and dust surface concentrations from a ground-based measurement network. In addition, the predicted vertical dust distribution was evaluated with vertical extinction profiles from the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP. To assess the diversity in forecast capability among the models, the analysis was extended to wind field (both surface and profile, synoptic conditions, emissions and deposition fluxes. Models predict the onset and evolution of the AOD for all analysed lead times. On average, differences among the models are larger than differences among lead times for each individual model. In spite of large differences in emission and deposition, the models present comparable skill for AOD. In general, models are better in predicting AOD than near-surface dust concentration over the Iberian Peninsula. Models tend to underestimate the long-range transport towards northern Europe. Our analysis suggests that this is partly due to difficulties in simulating the vertical distribution dust and horizontal wind. Differences in the size distribution and wet scavenging efficiency may also account for model diversity in long-range transport.

  17. Forecasting the northern African dust outbreak towards Europe in April 2011: a model intercomparison

    Science.gov (United States)

    Huneeus, N.; Basart, S.; Fiedler, S.; Morcrette, J.-J.; Benedetti, A.; Mulcahy, J.; Terradellas, E.; Pérez García-Pando, C.; Pejanovic, G.; Nickovic, S.; Arsenovic, P.; Schulz, M.; Cuevas, E.; Baldasano, J. M.; Pey, J.; Remy, S.; Cvetkovic, B.

    2016-04-01

    In the framework of the World Meteorological Organisation's Sand and Dust Storm Warning Advisory and Assessment System, we evaluated the predictions of five state-of-the-art dust forecast models during an intense Saharan dust outbreak affecting western and northern Europe in April 2011. We assessed the capacity of the models to predict the evolution of the dust cloud with lead times of up to 72 h using observations of aerosol optical depth (AOD) from the AErosol RObotic NETwork (AERONET) and the Moderate Resolution Imaging Spectroradiometer (MODIS) and dust surface concentrations from a ground-based measurement network. In addition, the predicted vertical dust distribution was evaluated with vertical extinction profiles from the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP). To assess the diversity in forecast capability among the models, the analysis was extended to wind field (both surface and profile), synoptic conditions, emissions and deposition fluxes. Models predict the onset and evolution of the AOD for all analysed lead times. On average, differences among the models are larger than differences among lead times for each individual model. In spite of large differences in emission and deposition, the models present comparable skill for AOD. In general, models are better in predicting AOD than near-surface dust concentration over the Iberian Peninsula. Models tend to underestimate the long-range transport towards northern Europe. Our analysis suggests that this is partly due to difficulties in simulating the vertical distribution dust and horizontal wind. Differences in the size distribution and wet scavenging efficiency may also account for model diversity in long-range transport.

  18. Technical Note: On the use of nudging for aerosol-climate model intercomparison studies

    Science.gov (United States)

    Zhang, K.; Wan, H.; Liu, X.; Ghan, S. J.; Kooperman, G. J.; Ma, P.-L.; Rasch, P. J.; Neubauer, D.; Lohmann, U.

    2014-08-01

    Nudging as an assimilation technique has seen increased use in recent years in the development and evaluation of climate models. Constraining the simulated wind and temperature fields using global weather reanalysis facilitates more straightforward comparison between simulation and observation, and reduces uncertainties associated with natural variabilities of the large-scale circulation. On the other hand, the forcing introduced by nudging can be strong enough to change the basic characteristics of the model climate. In the paper we show that for the Community Atmosphere Model version 5 (CAM5), due to the systematic temperature bias in the standard model and the sensitivity of simulated ice formation to anthropogenic aerosol concentration, nudging towards reanalysis results in substantial reductions in the ice cloud amount and the impact of anthropogenic aerosols on long-wave cloud forcing. In order to reduce discrepancies between the nudged and unconstrained simulations, and meanwhile take the advantages of nudging, two alternative experimentation methods are evaluated. The first one constrains only the horizontal winds. The second method nudges both winds and temperature, but replaces the long-term climatology of the reanalysis by that of the model. Results show that both methods lead to substantially improved agreement with the free-running model in terms of the top-of-atmosphere radiation budget and cloud ice amount. The wind-only nudging is more convenient to apply, and provides higher correlations of the wind fields, geopotential height and specific humidity between simulation and reanalysis. Results from both CAM5 and a second aerosol-climate model ECHAM6-HAM2 also indicate that compared to the wind-and-temperature nudging, constraining only winds leads to better agreement with the free-running model in terms of the estimated shortwave cloud forcing and the simulated convective activities. This suggests nudging the horizontal winds but not temperature is a

  19. NACP MsTMIP: Global and North American Driver Data for Multi-Model Intercomparison

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides environmental data that have been standardized and aggregated for use as input to carbon cycle models at global (0.5-degree resolution) and...

  20. NACP MsTMIP: Global and North American Driver Data for Multi-Model Intercomparison

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides environmental data that have been standardized and aggregated for use as input to carbon cycle models at global (0.5-degree...

  1. Inter-comparison of receptor models for PM source apportionment: Case study in an industrial area

    Science.gov (United States)

    Viana, M.; Pandolfi, M.; Minguillón, M. C.; Querol, X.; Alastuey, A.; Monfort, E.; Celades, I.

    2008-05-01

    Receptor modelling techniques are used to identify and quantify the contributions from emission sources to the levels and major and trace components of ambient particulate matter (PM). A wide variety of receptor models are currently available, and consequently the comparability between models should be evaluated if source apportionment data are to be used as input in health effects studies or mitigation plans. Three of the most widespread receptor models (principal component analysis, PCA; positive matrix factorization, PMF; chemical mass balance, CMB) were applied to a single PM10 data set (n=328 samples, 2002-2005) obtained from an industrial area in NE Spain, dedicated to ceramic production. Sensitivity and temporal trend analyses (using the Mann-Kendall test) were applied. Results evidenced the good overall performance of the three models (r2>0.83 and α>0.91×between modelled and measured PM10 mass), with a good agreement regarding source identification and high correlations between input (CMB) and output (PCA, PMF) source profiles. Larger differences were obtained regarding the quantification of source contributions (up to a factor of 4 in some cases). The combined application of different types of receptor models would solve the limitations of each of the models, by constructing a more robust solution based on their strengths. The authors suggest the combined use of factor analysis techniques (PCA, PMF) to identify and interpret emission sources, and to obtain a first quantification of their contributions to the PM mass, and the subsequent application of CMB. Further research is needed to ensure that source apportionment methods are robust enough for application to PM health effects assessments.

  2. From Past to future: the Paleoclimate Modelling Intercomparison Project's contribution to CMIP6

    Science.gov (United States)

    Kageyama, Masa; Braconnot, Pascale; Harrison, Sandy; Haywood, Alan; Jungclaus, Johann; Otto-Bliesner, Bette; Abe-Ouchi, Ayako

    2016-04-01

    Since the 1990s, PMIP has developed with the following objectives: 1/to evaluate the ability of climate models used for climate prediction in simulating well-documented past climates outside the range of present and recent climate variability; 2/to understand the mechanisms of these climate changes, in particular the role of the different climate feedbacks. To achieve these goals, PMIP has actively fostered paleo-data syntheses, multi-model analyses, including analyses of relationships between model results from past and future simulations, and model-data comparisons. For CMIP6, PMIP will focus on five past periods: - the Last Millennium (850 CE - present), to analyse natural climate variability on multidecadal or longer time-scales - the mid-Holocene, 6000 years ago, to compare model runs with paleodata for a period of warmer climate in the Northern Hemisphere, with an enhanced hydrological cycle - the Last Glacial Maximum, 21000 years ago, to evaluate the ability of climate models to represent a cold climate extreme and examine whether paleoinformation about this period can help and constrain climate sensitivity - the Last InterGlacial (~127,000 year ago), which provides a benchmark for a period of high sea-level stand - the mid-Pliocene warm period (~3.2 million years ago), which allows for the evaluation of the model's long-term response to a CO2 level analogous to the modern one. This poster will present the rationale of these "PMIP4-CMIP6" experiments. Participants are invited to come and discuss about the experimental set-up and the model output to be distributed via CMIP6. For more information and discussion of the PMIP4-CMIP6 experimental design, please visit: https://wiki.lsce.ipsl.fr/pmip3/doku.php/pmip3:cmip6:design:index

  3. A coarse resolution North Atlantic ocean circulation model: an intercomparison study with a paleoceanographic example

    Directory of Open Access Journals (Sweden)

    Dan Seidov

    Full Text Available Paleoreconstructions suggest that during the Last Glacial Maximum (LGM the North Atlantic circulation was noticeably different from its present state. However, the glacial salt conveyor belt is believed to be similar to the present-day's conveyor, albeit weaker and shallower because of an increased freshwater flux in high-latitudes. We present here the investigation of the conveyor operation based on ocean circulation modelling using two numerical models in parallel. The GFDL primitive equation model and a planetary geostrophic model are employed to address the problem of the paleocirculation modelling in cases of uncertain and sparse data comprising the glacial surface boundary conditions. The role of different simplifications that may be used in the ocean climate studies, including the role of grid resolution, bottom topography, coast-line, etc., versus glacial-interglacial changes of the ocean surface climatology is considered. The LGM reverse conveyor gyre appeared to be the most noticeable feature of the glacial-to-interglacial alteration of the ocean circulation. The reversed upper-ocean conveyor, weaker and subducting 'normal' conveyor in the intermediate depths, and the change of the deep-ocean return flow route are robust signatures of the glacial North Atlantic climate. The results are found to be 'model-independent' and fairly insensitive to all factors other than the onset of the glacial surface conditions.

  4. A coarse resolution North Atlantic ocean circulation model: an intercomparison study with a paleoceanographic example

    Directory of Open Access Journals (Sweden)

    D. Seidov

    1996-02-01

    Full Text Available Paleoreconstructions suggest that during the Last Glacial Maximum (LGM the North Atlantic circulation was noticeably different from its present state. However, the glacial salt conveyor belt is believed to be similar to the present-day's conveyor, albeit weaker and shallower because of an increased freshwater flux in high-latitudes. We present here the investigation of the conveyor operation based on ocean circulation modelling using two numerical models in parallel. The GFDL primitive equation model and a planetary geostrophic model are employed to address the problem of the paleocirculation modelling in cases of uncertain and sparse data comprising the glacial surface boundary conditions. The role of different simplifications that may be used in the ocean climate studies, including the role of grid resolution, bottom topography, coast-line, etc., versus glacial-interglacial changes of the ocean surface climatology is considered. The LGM reverse conveyor gyre appeared to be the most noticeable feature of the glacial-to-interglacial alteration of the ocean circulation. The reversed upper-ocean conveyor, weaker and subducting 'normal' conveyor in the intermediate depths, and the change of the deep-ocean return flow route are robust signatures of the glacial North Atlantic climate. The results are found to be 'model-independent' and fairly insensitive to all factors other than the onset of the glacial surface conditions.

  5. Global Climate Models Intercomparison of Anthropogenic Aerosols Effects on Regional Climate over North Pacific

    Science.gov (United States)

    Hu, J.; Zhang, R.; Wang, Y.; Ming, Y.; Lin, Y.; Pan, B.

    2015-12-01

    Aerosols can alter atmospheric radiation and cloud physics, which further exert impacts on weather and global climate. With the development and industrialization of the developing Asian countries, anthropogenic aerosols have received considerable attentions and remain to be the largest uncertainty in the climate projection. Here we assess the performance of two stat-of-art global climate models (National Center for Atmospheric Research-Community Atmosphere Model 5 (CAM5) and Geophysical Fluid Dynamics Laboratory Atmosphere Model 3 (AM3)) in simulating the impacts of anthropogenic aerosols on North Pacific storm track region. By contrasting two aerosol scenarios, i.e. present day (PD) and pre-industrial (PI), both models show aerosol optical depth (AOD) enhanced by about 22%, with CAM5 AOD 40% lower in magnitude due to the long range transport of anthropogenic aerosols. Aerosol effects on the ice water path (IWP), stratiform precipitation, convergence and convection strengths in the two models are distinctive in patterns and magnitudes. AM3 shows qualitatively good agreement with long-term satellite observations, while CAM5 overestimates convection and liquid water path resulting in an underestimation of large-scale precipitation and IWP. Due to coarse resolution and parameterization in convection schemes, both models' performance on convection needs to be improved. Aerosols performance on large-scale circulation and radiative budget are also examined in this study.

  6. Intercomparison of lepton-nucleus scattering models in the quasielastic region

    Science.gov (United States)

    Sobczyk, Joanna E.

    2017-10-01

    I present a discussion of the models of nuclear effects used to describe the inclusive electron-nucleus scattering in the quasielastic (QE) peak region, aiming to compare them and to draw conclusions about their reliability when applied in neutrino-nucleus interactions. A basic motivation is to reduce the systematic errors in the neutrino oscillation experiments. I concentrate on the neutrino energy profile of the T2K experiment, which provides me with a region of the greatest importance in terms of the highest contribution to the charge-current quasielastic (CCQE) cross section. Only electron-nucleus data that overlap with this region is chosen. In order to clarify the analysis, I split the data sets into three groups and draw conclusions separately from each one of them. Six models are selected for this comparison: Benhar's spectral function with and without the final-state interactions (Benhar's SF + FSI); the Valencia spectral function (Valencia SF), for higher energy transfers only with the hole spectral function; the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) model; and the local and global Fermi gas models. The latter two are included as a benchmark to quantify the roles of various nuclear effects. All six models are often used in neutrino scattering studies. A short theoretical description of each model is given. Although in the selected data sets the QE mechanism dominates, I also discuss the possible impact of the 2p2h and the Δ contributions.

  7. Evaluation and intercomparison of three-dimensional global marine carbon cycle models

    Energy Technology Data Exchange (ETDEWEB)

    Caldeira, K., LLNL

    1998-07-01

    The addition of carbon dioxide to the atmosphere from fossil fuel burning and deforestation has profound implications for the future of the earth`s climate and hence for humankind itself. Society is looking toward the community of environmental scientists to predict the consequences of increased atmospheric carbon dioxide so that sound input can be provided to economists, environmental engineers, and, ultimately, policy makers. Environmental scientists have responded to this challenge through the creation of several ambitious, highly-coordinated programs, each focused on a different aspect of the climate system. Recognizing that numerical models, be they relatively simple statistical-empirical models or highly complex process-oriented models, are the only means for predicting the future of the climate system, all of these programs include the development of accurate, predictive models as a central goal. The Joint Global Ocean Flux Study (JGOFS) is one such program, and was built on the well-founded premise that biological, chemical and physical oceanographic processes have a profound influence on the C0{sub 2} content of the atmosphere. The, cap-stone, phase of JGOFS, the Synthesis and Modeling Project (SMP), is charged with the development of models that can be used in the prediction of future air-sea partitioning of C0{sub 2}. JGOFS, particularly the SMP phase, has a number of interim goals as well, including the determination of fluxes and inventories of carbon in the modern ocean that air germane to the air-sea partitioning of C0{sub 2}. Models have a role to play here too, because many of these fluxes and inventories, such as the distributions of anthropogenic dissolved inorganic carbon (DIC), new primary production and aphotic zone remineralization, while not amenable to direct observation on the large scale, can be determined using a variety of modeling approaches (Siegenthaler and Oeschger, 1987; Maier-Reimer and Hasselman, 1987, Bacastow and Maier

  8. Technical Note: On the use of nudging for aerosol–climate model intercomparison studies

    Directory of Open Access Journals (Sweden)

    K. Zhang

    2014-08-01

    Full Text Available Nudging as an assimilation technique has seen increased use in recent years in the development and evaluation of climate models. Constraining the simulated wind and temperature fields using global weather reanalysis facilitates more straightforward comparison between simulation and observation, and reduces uncertainties associated with natural variabilities of the large-scale circulation. On the other hand, the forcing introduced by nudging can be strong enough to change the basic characteristics of the model climate. In the paper we show that for the Community Atmosphere Model version 5 (CAM5, due to the systematic temperature bias in the standard model and the sensitivity of simulated ice formation to anthropogenic aerosol concentration, nudging towards reanalysis results in substantial reductions in the ice cloud amount and the impact of anthropogenic aerosols on long-wave cloud forcing. In order to reduce discrepancies between the nudged and unconstrained simulations, and meanwhile take the advantages of nudging, two alternative experimentation methods are evaluated. The first one constrains only the horizontal winds. The second method nudges both winds and temperature, but replaces the long-term climatology of the reanalysis by that of the model. Results show that both methods lead to substantially improved agreement with the free-running model in terms of the top-of-atmosphere radiation budget and cloud ice amount. The wind-only nudging is more convenient to apply, and provides higher correlations of the wind fields, geopotential height and specific humidity between simulation and reanalysis. Results from both CAM5 and a second aerosol–climate model ECHAM6-HAM2 also indicate that compared to the wind-and-temperature nudging, constraining only winds leads to better agreement with the free-running model in terms of the estimated shortwave cloud forcing and the simulated convective activities. This suggests nudging the horizontal winds but

  9. Radionuclides in fruit systems: Model prediction-experimental data intercomparison study

    International Nuclear Information System (INIS)

    Ould-Dada, Z.; Carini, F.; Eged, K.; Kis, Z.; Linkov, I.; Mitchell, N.G.; Mourlon, C.; Robles, B.; Sweeck, L.; Venter, A.

    2006-01-01

    This paper presents results from an international exercise undertaken to test model predictions against an independent data set for the transfer of radioactivity to fruit. Six models with various structures and complexity participated in this exercise. Predictions from these models were compared against independent experimental measurements on the transfer of 134 Cs and 85 Sr via leaf-to-fruit and soil-to-fruit in strawberry plants after an acute release. Foliar contamination was carried out through wet deposition on the plant at two different growing stages, anthesis and ripening, while soil contamination was effected at anthesis only. In the case of foliar contamination, predicted values are within the same order of magnitude as the measured values for both radionuclides, while in the case of soil contamination models tend to under-predict by up to three orders of magnitude for 134 Cs, while differences for 85 Sr are lower. Performance of models against experimental data is discussed together with the lessons learned from this exercise

  10. Technical Note: On the Use of Nudging for Aerosol-Climate Model Intercomparison Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai; Wan, Hui; Liu, Xiaohong; Ghan, Steven J.; Kooperman, G. J.; Ma, Po-Lun; Rasch, Philip J.; Neubauer, David; Lohmann, U.

    2014-08-26

    Nudging is an assimilation technique widely used in the development and evaluation of climate models. Con- straining the simulated wind and temperature fields using global weather reanalysis facilitates more straightforward comparison between simulation and observation, and reduces uncertainties associated with natural variabilities of the large-scale circulation. On the other hand, the artificial forcing introduced by nudging can be strong enough to change the basic characteristics of the model climate. In the paper we show that for the Community Atmosphere Model version 5, due to the systematic temperature bias in the standard model and the relatively strong sensitivity of homogeneous ice nucleation to aerosol concentration, nudging towards reanalysis results in substantial reductions in the ice cloud amount and the impact of anthropogenic aerosols on longwave cloud forcing. In order to reduce discrepancies between the nudged and unconstrained simulations and meanwhile take the advantages of nudging, two alternative experimentation methods are evaluated. The first one constrains only the horizontal winds. The second method nudges both winds and temperature, but replaces the long-term climatology of the reanalysis by that of the model. Results show that both methods lead to substantially improved agreement with the free-running model in terms of the top-of-atmosphere radiation budget and cloud ice amount. The wind-only nudging is more convenient to apply, and provides higher correlations of the wind fields, geopotential height and specific humidity between simulation and reanalysis. This suggests that nudging the horizontal winds but not temperature is a good strategy, especially for studies that involve both warm and cold clouds.

  11. Aerosol indirect effects -- general circulation model intercomparison and evaluation with satellite data

    Energy Technology Data Exchange (ETDEWEB)

    Quaas, Johannes; Ming, Yi; Menon, Surabi; Takemura, Toshihiko; Wang, Minghuai; Penner, Joyce E.; Gettelman, Andrew; Lohmann, Ulrike; Bellouin, Nicolas; Boucher, Olivier; Sayer, Andrew M.; Thomas, Gareth E.; McComiskey, Allison; Feingold, Graham; Hoose, Corinna; Kristjansson, Jon Egill; Liu, Xiaohong; Balkanski, Yves; Donner, Leo J.; Ginoux, Paul A.; Stier, Philip; Feichter, Johann; Sednev, Igor; Bauer, Susanne E.; Koch, Dorothy; Grainger, Roy G.; Kirkevag, Alf; Iversen, Trond; Seland, Oyvind; Easter, Richard; Ghan, Steven J.; Rasch, Philip J.; Morrison, Hugh; Lamarque, Jean-Francois; Iacono, Michael J.; Kinne, Stefan; Schulz, Michael

    2009-04-10

    Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterizes aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (Ta) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (Nd) compares relatively well to the satellite data at least over the ocean. The relationship between Ta and liquid water path is simulated much too strongly by the models. It is shown that this is partly related to the representation of the second aerosol indirect effect in terms of autoconversion. A positive relationship between total cloud fraction (fcld) and Ta as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong fcld - Ta relationship, our results indicate that none can be identified as unique explanation. Relationships similar to the ones found in satellite data between Ta and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - Ta relationship show a strong positive correlation between Ta and fcld The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of Ta, and parameterisation assumptions such as a lower bound on Nd

  12. The Agricultural Model Intercomparison and Improvement Project (AgMIP) Town Hall

    Science.gov (United States)

    Ruane, Alex; Rosenzweig, Cynthia; Kyle, Page; Basso, Bruno; Winter, Jonathan; Asseng, Senthold

    2015-01-01

    AgMIP (www.agmip.org) is an international community of climate, crop, livestock, economics, and IT experts working to further the development and application of multi-model, multi-scale, multi-disciplinary agricultural models that can inform policy and decision makers around the world. This meeting will engage the AGU community by providing a brief overview of AgMIP, in particular its new plans for a Coordinated Global and Regional Assessment of climate change impacts on agriculture and food security for AR6. This Town Hall will help identify opportunities for participants to become involved in AgMIP and its 30+ activities.

  13. Modelling of atmospheric mid-infrared radiative transfer: the AMIL2DA algorithm intercomparison experiment

    International Nuclear Information System (INIS)

    Clarmann, T. von; Hoepfner, M.; Funke, B.; Lopez-Puertas, M.; Dudhia, A.; Jay, V.; Schreier, F.; Ridolfi, M.; Ceccherini, S.; Kerridge, B.J.; Reburn, J.; Siddans, R.

    2003-01-01

    When retrieving atmospheric parameters from radiance spectra, the forward modelling of radiative transfer through the Earth's atmosphere plays a key role, since inappropriate modelling directly maps on to the retrieved state parameters. In the context of pre-launch activities of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) experiment, which is a high resolution limb emission sounder for measurement of atmospheric composition and temperature, five scientific groups intercompared their forward models within the framework of the Advanced MIPAS Level 2 Data Analysis (AMIL2DA) project. These forward models have been developed, or, in certain respects, adapted in order to be used as part of the groups' MIPAS data processing. The following functionalities have been assessed: the calculation of line strengths including non-local thermodynamic equilibrium, the evaluation of the spectral line shape, application of chi-factors and semi-empirical continua, the interpolation of pre-tabulated absorption cross sections in pressure and temperature, line coupling, atmospheric ray tracing, the integration of the radiative transfer equation through an inhomogeneous atmosphere, the convolution of monochromatic spectra with an instrument line shape function, and the integration of the incoming radiances over the instrument field of view

  14. Intercomparison and validation of operational coastal-scale models, the experience of the project MOMAR.

    Science.gov (United States)

    Brandini, C.; Coudray, S.; Taddei, S.; Fattorini, M.; Costanza, L.; Lapucci, C.; Poulain, P.; Gerin, R.; Ortolani, A.; Gozzini, B.

    2012-04-01

    The need for regional governments to implement operational systems for the sustainable management of coastal waters, in order to meet the requirements imposed by legislation (e.g. EU directives such as WFD, MSFD, BD and relevant national legislation) often lead to the implementation of coastal measurement networks and to the construction of computational models that surround and describe parts of regional seas without falling in the classic definition of regional/coastal models. Although these operational models may be structured to cover parts of different oceanographic basins, they can have considerable advantages and highlight relevant issues, such as the role of narrow channels, straits and islands in coastal circulation, as both in physical and biogeochemical processes such as in the exchanges of water masses among basins. Two models of this type were made in the context of cross-border European project MOMAR: an operational model of the Tuscan Archipelago sea and one around the Corsica coastal waters, which are both located between the Tyrrhenian and the Algerian-Ligurian-Provençal basins. Although these two models were based on different computer codes (MARS3D and ROMS), they have several elements in common, such as a 400 m resolution, boundary conditions from the same "father" model, and an important area of overlap, the Corsica channel, which has a key role in the exchange of water masses between the two oceanographic basins. In this work we present the results of the comparison of these two ocean forecasting systems in response to different weather and oceanographic forcing. In particular, we discuss aspects related to the validation of the two systems, and a systematic comparison between the forecast/hindcast based on such hydrodynamic models, as regards to both operational models available at larger scale, both to in-situ measurements made by fixed or mobile platforms. In this context we will also present the results of two oceanographic cruises in the

  15. Aerosol indirect effects ? general circulation model intercomparison and evaluation with satellite data

    Energy Technology Data Exchange (ETDEWEB)

    Quaas, Johannes; Ming, Yi; Menon, Surabi; Takemura, Toshihiko; Wang, Minghuai; Penner, Joyce E.; Gettelman, Andrew; Lohmann, Ulrike; Bellouin, Nicolas; Boucher, Olivier; Sayer, Andrew M.; Thomas, Gareth E.; McComiskey, Allison; Feingold, Graham; Hoose, Corinna; Kristansson, Jon Egill; Liu, Xiaohong; Balkanski, Yves; Donner, Leo J.; Ginoux, Paul A.; Stier, Philip; Grandey, Benjamin; Feichter, Johann; Sednev, Igor; Bauer, Susanne E.; Koch, Dorothy; Grainger, Roy G.; Kirkevag, Alf; Iversen, Trond; Seland, Oyvind; Easter, Richard; Ghan, Steven J.; Rasch, Philip J.; Morrison, Hugh; Lamarque, Jean-Francois; Iacono, Michael J.; Kinne, Stefan; Schulz, Michael

    2010-03-12

    Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth ({tau}{sub a}) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. It is found that the model-simulated influence of aerosols on cloud droplet number concentration (N{sub d}) compares relatively well to the satellite data at least over the ocean. The relationship between {tau}{sub a} and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (f{sub cld}) and {tau}{sub a} as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong f{sub cld} - {tau}{sub a} relationship, our results indicate that none can be identified as a unique explanation. Relationships similar to the ones found in satellite data between {tau}{sub a} and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - {tau}{sub a} relationship show a strong positive correlation between {tau}{sub a} and f{sub cld} The short-wave total aerosol radiative forcing as simulated by the GCMs is

  16. Eddy dynamics over continental slopes under retrograde winds: Insights from a model inter-comparison

    Science.gov (United States)

    Wang, Yan; Stewart, Andrew L.

    2018-01-01

    Mesoscale eddies are ubiquitous in the ocean and play a key role in exchanges across continental slopes. In this study the properties of wind-driven baroclinic turbulence are investigated using eddy-resolving process simulations, focusing on the case of retrograde winds that arises around the margins of the subtropical gyres. In contrast to a flat-bottomed ocean, over steep slopes eddies develop from baroclinic instabilities are confined to the top few hundred meters. Deeper in the water column baroclinic instability and vertical momentum transfer are suppressed, so wind-input momentum is exported toward the open ocean by eddies before traversing down to the ocean bed. Close to the sloping topography, eddy energy sourced from the upper ocean is converted to potential energy, steepening isopycnals and driving bottom-trapped prograde flows. This process is associated with upgradient lateral buoyancy fluxes and downgradient isopycnal potential vorticity fluxes, and cannot be reproduced via linear stability calculations. These properties of wind-driven shelf/slope turbulence are contrasted against simulations with flat bathymetry. The key differences described above hinge on the flow close to the steep topographic slope, which may be sensitive to the model's vertical coordinate system. The simulations are therefore replicated using models that employ geopotential coordinates, terrain-following coordinates, and isopycnal coordinates. Quantitative inter-model discrepancies in the momentum and energy budgets are much more pronounced in the presence of a steep bottom slope. However, the key findings of this study are consistent across the models, suggesting that they are robust and warrant incorporation into parameterizations of eddy transfer across continental slopes.

  17. Intercomparison of the terrestrial food chain models FOOD-MARC and ECOSYS

    International Nuclear Information System (INIS)

    Proehl, G.; Friedland, W.; Paretzke, H.G.

    1985-12-01

    Time-dependent food chain models, FOOD-MARC and ECOSYS, have been developed independently at the NRPB and at the GSF respectively. Both models are compared with respect to the model assumptions and the parameters used. A further point of this study is the analysis of the influence of actual differences in agricultural conditions in the United Kingdom and the Federal Republic of Germany on the results. A single deposition of 1 Bq/m 2 was assumed of selected radionuclides on an area in agricultural use. The endpoints considered are the resulting activity concentrations in plant and animal foodstuffs as a function of time after deposition. The cumulative concentrations integrated over 50 years are calculated. A deposition in winter (January 1) and another one in summer (July 1) are considered separately to point out the seasonal influence on the contamination of foodstuffs. In this comparison, the products vegetables, grain, roots, milk, meat, and the radionuclides Sr-89/90, Ru-106, Cs-134/137, I-129/131/133, and Pu-239 are taken into account. The activity concentrations in food products are calculated for the times 7 d, 30 d, 100 d, 200 d, 1 a, 2 a, 5 a, 10 a, 20 a, and 50 a after the single deposition on January 1 or July 1. (orig./HP)

  18. An intercomparison of regional climate model data for hydrological impact studies in Denmark

    DEFF Research Database (Denmark)

    Van Roosmalen, Lieke Petronella G; Christensen, Jens Hesselbjerg; Butts, Michael

    2010-01-01

    The use of high-resolution regional climate models (RCM) to examine the hydrological impacts of climate change has grown significantly in recent years due to the improved representation of the local climate. However, the application is not straightforward because most RCMs are subject to consider......The use of high-resolution regional climate models (RCM) to examine the hydrological impacts of climate change has grown significantly in recent years due to the improved representation of the local climate. However, the application is not straightforward because most RCMs are subject...... to considerable systematic errors. In this study, projected climate change data from the RCM HIRHAM4 are used to generate climate scenario time series of precipitation, temperature, and reference evapotranspiration for the period 2071-2100 for hydrological impact assessments in Denmark. RCM output for the present......-day period (1961-1990) are compared to an observational data set, with precipitation corrected for undercatch and wetting losses, to quantify systematic model errors. A delta change method is applied to cope with these biases. A question arises as to how variable the climate change signals are...

  19. An intercomparison of several diagnostic meteorological processors used in mesoscale air quality modeling

    Energy Technology Data Exchange (ETDEWEB)

    Vimont, J.C. [National Park Service, Lakewood, CO (United States); Scire, J.S. [Sigma Research Corp., Concord, MA (United States)

    1994-12-31

    A major component, and area of uncertainty, in mesoscale air quality modeling, is the specification of the meteorological fields which affect the transport and dispersion of pollutants. Various options are available for estimating the wind and mixing depth fields over a mesoscale domain. Estimates of the wind field can be obtained from spatial and temporal interpolation of available observations or from diagnostic meteorological models, which estimate a meteorological field from available data and adjust those fields based on parameterizations of physical processes. A major weakness of these processors is their dependence on spatially and temporally sparse input data, particularly upper air data. These problems are exacerbated in regions of complex terrain and along the shorelines of large bodies of water. Similarly, the estimation of mixing depth is also reliant upon sparse observations and the parameterization of the convective and mechanical processes. The meteorological processors examined in this analysis were developed to drive different Lagrangian puff models. This paper describes the algorithms these processors use to estimate the wind fields and mixing depth fields.

  20. Improving National Water Modeling: An Intercomparison of two High-Resolution, Continental Scale Models, CONUS-ParFlow and the National Water Model

    Science.gov (United States)

    Tijerina, D.; Gochis, D.; Condon, L. E.; Maxwell, R. M.

    2017-12-01

    Development of integrated hydrology modeling systems that couple atmospheric, land surface, and subsurface flow is growing trend in hydrologic modeling. Using an integrated modeling framework, subsurface hydrologic processes, such as lateral flow and soil moisture redistribution, are represented in a single cohesive framework with surface processes like overland flow and evapotranspiration. There is a need for these more intricate models in comprehensive hydrologic forecasting and water management over large spatial areas, specifically the Continental US (CONUS). Currently, two high-resolution, coupled hydrologic modeling applications have been developed for this domain: CONUS-ParFlow built using the integrated hydrologic model ParFlow and the National Water Model that uses the NCAR Weather Research and Forecasting hydrological extension package (WRF-Hydro). Both ParFlow and WRF-Hydro include land surface models, overland flow, and take advantage of parallelization and high-performance computing (HPC) capabilities; however, they have different approaches to overland subsurface flow and groundwater-surface water interactions. Accurately representing large domains remains a challenge considering the difficult task of representing complex hydrologic processes, computational expense, and extensive data needs; both models have accomplished this, but have differences in approach and continue to be difficult to validate. A further exploration of effective methodology to accurately represent large-scale hydrology with integrated models is needed to advance this growing field. Here we compare the outputs of CONUS-ParFlow and the National Water Model to each other and with observations to study the performance of hyper-resolution models over large domains. Models were compared over a range of scales for major watersheds within the CONUS with a specific focus on the Mississippi, Ohio, and Colorado River basins. We use a novel set of approaches and analysis for this comparison

  1. Tables and intercomparisons of evolutionary sequences of models for massive stars

    International Nuclear Information System (INIS)

    Chin, Chaowen; Stothers, R.B.

    1990-01-01

    Tables of evolutionary sequences of models for massive stars have been prepared for a variety of physical input parameters that are normally treated as free. These parameters include the interior convective mixing scheme, the mixing length in the outer convective envelope, the rate of stellar-wind mass loss, the initial stellar mass, and the initial chemical composition. Ranges of specified initial mass and initial chemical composition are M = 10-120 solar masses, Xe = 0.602-0.739, and Ze = 0.021-0.044. The tables cover evolution of the star from the ZAMS to either the end of core H burning or the end of core He burning. Differences among the evolutionary tracks are illustrated primarily in terms of the interior mixing scheme, since the amount and timing of stellar wind mass loss are still very uncertain for initial masses above about 30 solar masses. 52 refs

  2. NRC model simulations in support of the hydrologic code intercomparison study (HYDROCOIN): Level 1-code verification

    International Nuclear Information System (INIS)

    1988-03-01

    HYDROCOIN is an international study for examining ground-water flow modeling strategies and their influence on safety assessments of geologic repositories for nuclear waste. This report summarizes only the combined NRC project temas' simulation efforts on the computer code bench-marking problems. The codes used to simulate thesee seven problems were SWIFT II, FEMWATER, UNSAT2M USGS-3D, AND TOUGH. In general, linear problems involving scalars such as hydraulic head were accurately simulated by both finite-difference and finite-element solution algorithms. Both types of codes produced accurate results even for complex geometrics such as intersecting fractures. Difficulties were encountered in solving problems that invovled nonlinear effects such as density-driven flow and unsaturated flow. In order to fully evaluate the accuracy of these codes, post-processing of results using paricle tracking algorithms and calculating fluxes were examined. This proved very valuable by uncovering disagreements among code results even through the hydraulic-head solutions had been in agreement. 9 refs., 111 figs., 6 tabs

  3. Intercomparison of the Charnock and COARE bulk wind stress formulations for coastal ocean modelling

    Directory of Open Access Journals (Sweden)

    J. M. Brown

    2013-08-01

    Full Text Available The accurate parameterisation of momentum and heat transfer across the air–sea interface is vital for realistic simulation of the atmosphere–ocean system. In most modelling applications accurate representation of the wind stress is required to numerically reproduce surge, coastal ocean circulation, surface waves, turbulence and mixing. Different formulations can be implemented and impact the accuracy of the instantaneous and long-term residual circulation, the surface mixed layer, and the generation of wave-surge conditions. This, in turn, affects predictions of storm impact, sediment pathways, and coastal resilience to climate change. The specific numerical formulation needs careful selection to ensure the accuracy of the simulation. Two wind stress parameterisations widely used in the ocean circulation and the storm surge communities respectively are studied with focus on an application to the NW region of the UK. Model–observation validation is performed at two nearshore and one estuarine ADCP (acoustic Doppler current profiler stations in Liverpool Bay, a hypertidal region of freshwater influence (ROFI with vast intertidal areas. The period of study covers both calm and extreme conditions to test the robustness of the 10 m wind stress component of the Coupled Ocean–Atmosphere Response Experiment (COARE bulk formulae and the standard Charnock relation. In this coastal application a realistic barotropic–baroclinic simulation of the circulation and surge elevation is set-up, demonstrating greater accuracy occurs when using the Charnock relation, with a constant Charnock coefficient of 0.0185, for surface wind stress during this one month period.

  4. ABACC's laboratory intercomparison program

    International Nuclear Information System (INIS)

    Almeida, Gevaldo L. de; Esteban, Adolfo; Almeida, Silvio G. de; Araujo, Radier M. de; Rocha, Zildete

    1996-01-01

    A Laboratory Intercomparison Program involving Brazilian and Argentine laboratories, with the special participation of New Brunswick Laboratory - DOE and IAEA Seibersdorf Safeguards Laboratory, was implanted by ABACC having as main purpose to qualify a network to provide analytical services to this Agency on its role as administrator of the Common System of Accountability and Control of Nuclear Materials. For the first round robin of this Program, 15 laboratories were invited to perform elemental analysis on UO 2 samples, by using any desired method. Thirteen confirmed the participation and 10 reported the results. After an evaluation of the results by using a Two-Way Variance Analysis applied to a nested error model, it was found that 5 of them deviate less than 0.1% from the reference value established for the UO 2 uranium contents, being thus situated within the limits adopted for the target values, while the remaining ones reach a maximal deviation of 0.44%. The outcome of this evaluation, was sent to the laboratories, providing them with a feedback to improve their performance by applying corrective actions to the detected sources of errors or bias related to the methods techniques and procedures. (author)

  5. Experimental design for three interrelated marine ice sheet and ocean model intercomparison projects: MISMIP v. 3 (MISMIP +), ISOMIP v. 2 (ISOMIP +) and MISOMIP v. 1 (MISOMIP1)

    Energy Technology Data Exchange (ETDEWEB)

    Asay-Davis, Xylar S. [Potsdam Inst. for Climate Impact Research (Germany). Earth System Analysis; Cornford, Stephen L. [Univ. of Bristol (United Kingdom). Centre for Polar Observation and Modelling; Durand, Gaël [Centre National de la Recherche Scientifique (CNRS), Grenoble (France); Univ. of Grenoble (France); Galton-Fenzi, Benjamin K. [Australian Antarctic Division and Antarctic Climate and Ecosystems Cooperative Research Centre, Tasmania (Australia); Gladstone, Rupert M. [Antarctic Climate and Ecosystems Cooperative Research Centre, Tasmania (Australia); ETH Zurich (Switzerland). Research Center for Hydraulic Engineering; Gudmundsson, G. Hilmar [British Antarctic Survey, Cambridge (United Kingdom); Hattermann, Tore [Akvaplan-niva, Tromso (Norway); Helmholtz Centre for Polar and Marine Research, Bremerhaven (Germany). Alfred Wegener Inst.; Holland, David M. [New York Univ. (NYU), NY (United States)' . Courant Inst. of Mathematical Sciences; Holland, Denise [New York Univ. (NYU), Abu Dahabi (United Arab Emirates); Holland, Paul R. [British Antarctic Survey, Cambridge (United Kingdom); Martin, Daniel F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mathiot, Pierre [British Antarctic Survey, Cambridge (United Kingdom); Met Office, Exeter (United Kingdom); Pattyn, Frank [Univ. of Libre, Brussels (Belgium). Lab. of Glaciology; Seroussi, Hélène [California Inst. of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab.

    2016-01-01

    Coupled ice sheet-ocean models capable of simulating moving grounding lines are just becoming available. Such models have a broad range of potential applications in studying the dynamics of marine ice sheets and tidewater glaciers, from process studies to future projections of ice mass loss and sea level rise. The Marine Ice Sheet-Ocean Model Intercomparison Project (MISOMIP) is a community effort aimed at designing and coordinating a series of model intercomparison projects (MIPs) for model evaluation in idealized setups, model verification based on observations, and future projections for key regions of the West Antarctic Ice Sheet (WAIS).

    Here we describe computational experiments constituting three interrelated MIPs for marine ice sheet models and regional ocean circulation models incorporating ice shelf cavities. These consist of ice sheet experiments under the Marine Ice Sheet MIP third phase (MISMIP+), ocean experiments under the Ice Shelf-Ocean MIP second phase (ISOMIP+) and coupled ice sheet-ocean experiments under the MISOMIP first phase (MISOMIP1). All three MIPs use a shared domain with idealized bedrock topography and forcing, allowing the coupled simulations (MISOMIP1) to be compared directly to the individual component simulations (MISMIP+ and ISOMIP+). The experiments, which have qualitative similarities to Pine Island Glacier Ice Shelf and the adjacent region of the Amundsen Sea, are designed to explore the effects of changes in ocean conditions, specifically the temperature at depth, on basal melting and ice dynamics. In future work, differences between model results will form the basis for the evaluation of the participating models.

  6. Pitfalls and modelling inconsistencies in computational radiation dosimetry: Lessons learnt from the QUADOS intercomparison. Part I: Neutrons and uncertainties

    International Nuclear Information System (INIS)

    Siebert, B. R. L.; Tanner, R. J.; Chartier, J. L.; Agosteo, S.; Grosswendt, B.; Gualdrini, G.; Menard, S.; Kodeli, I.; Leuthold, G. P.; Price, R. A.; Tagziria, H.; Terrissol, M.; Zankl, M.

    2006-01-01

    The QUADOS EU cost shared action conducted an intercomparison on the usage of numerical methods in radiation protection and dosimetry. The eight problems proposed were intended to test the usage of Monte Carlo and deterministic methods by assessing the accuracy with which the codes are applied and also the methods used to evaluate uncertainty in the answer gained through these methods. The overall objective was to spread good practice through the community and give users information on how to assess the uncertainties associated with their calculated results. (authors)

  7. Assessing radiation impact at a protected coastal sand dune site: an intercomparison of models for estimating the radiological exposure of non-human biota

    International Nuclear Information System (INIS)

    Wood, Michael D.; Beresford, Nicholas A.; Barnett, Catherine L.; Copplestone, David; Leah, Richard T.

    2009-01-01

    This paper presents the application of three publicly available biota dose assessment models (the ERICA Tool, R and D128/SP1a and RESRAD-BIOTA) to an assessment of the Drigg coastal sand dunes. Using measured 90 Sr, 99 Tc, 137 Cs, 238 Pu, 239+240 Pu and 241 Am activity concentrations in sand dune soil, activity concentration and dose rate predictions are made for a range of organisms including amphibians, birds, invertebrates, mammals, reptiles, plants and fungi. Predicted biota activity concentrations are compared to measured data where available. The main source of variability in the model predictions is the transfer parameters used and it is concluded that developing the available transfer databases should be a focus of future research effort. The value of taking an informed user approach to investigate the way in which models may be expected to be applied in practice is highlighted and a strategy for the future development of intercomparison exercises is presented.

  8. SOIL moisture data intercomparison

    Science.gov (United States)

    Kerr, Yann; Rodriguez-Frenandez, Nemesio; Al-Yaari, Amen; Parens, Marie; Molero, Beatriz; Mahmoodi, Ali; Mialon, Arnaud; Richaume, Philippe; Bindlish, Rajat; Mecklenburg, Susanne; Wigneron, Jean-Pierre

    2016-04-01

    The Soil Moisture and Ocean Salinity satellite (SMOS) was launched in November 2009 and started delivering data in January 2010. Subsequently, the satellite has been in operation for over 6 years while the retrieval algorithms from Level 1 to Level 2 underwent significant evolutions as knowledge improved. Other approaches for retrieval at Level 2 over land were also investigated while Level 3 and 4 were initiated. In this présentation these improvements are assessed by inter-comparisons of the current Level 2 (V620) against the previous version (V551) and new products either using neural networks or Level 3. In addition a global evaluation of different SMOS soil moisture (SM) products is performed comparing products with those of model simulations and other satellites (AMSR E/ AMSR2 and ASCAT). Finally, all products were evaluated against in situ measurements of soil moisture (SM). The study demonstrated that the V620 shows a significant improvement (including those at level1 improving level2)) with respect to the earlier version V551. Results also show that neural network based approaches can yield excellent results over areas where other products are poor. Finally, global comparison indicates that SMOS behaves very well when compared to other sensors/approaches and gives consistent results over all surfaces from very dry (African Sahel, Arizona), to wet (tropical rain forests). RFI (Radio Frequency Interference) is still an issue even though detection has been greatly improved while RFI sources in several areas of the world are significantly reduced. When compared to other satellite products, the analysis shows that SMOS achieves its expected goals and is globally consistent over different eco climate regions from low to high latitudes and throughout the seasons.

  9. Multi-model Mean Nitrogen and Sulfur Deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Evaluation Historical and Projected Changes

    Science.gov (United States)

    Lamarque, J.-F.; Dentener, F.; McConnell, J.; Ro, C.-U.; Shaw, M.; Vet, R.; Bergmann, D.; Cameron-Smith, P.; Doherty, R.; Faluvegi, G.; hide

    2013-01-01

    We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000-2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. For this time slice, we find a multi-model mean deposition of 50 Tg(N) yr1 from nitrogen oxide emissions, 60 Tg(N) yr1 from ammonia emissions, and 83 Tg(S) yr1 from sulfur emissions. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching 1300 mg(N) m2 yr1 averaged over regional to continental scale regions in RCP 2.6 and 8.5, 3050 larger than the values in any region currently (2000). The new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.

  10. Multi-model Mean Nitrogen and Sulfur Deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Evaluation of Historical and Projected Future Changes

    Energy Technology Data Exchange (ETDEWEB)

    Lamarque, Jean-Francois; Dentener, Frank; McConnell, J.R.; Ro, C-U; Shaw, Mark; Vet, Robert; Bergmann, D.; Cameron-Smith, Philip; Dalsoren, S.; Doherty, R.; Faluvegi, G.; Ghan, Steven J.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Plummer, David; Shindell, Drew; Skeie, R. B.; Stevenson, D. S.; Strode, S.; Zeng, G.; Curran, M.; Dahl-Jensen, D.; Das, S.; Fritzsche, D.; Nolan, M.

    2013-08-20

    We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000-2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States, but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching >1300 mgN/m2/yr averaged over regional to continental scale regions in RCP 2.6 and 8.5, ~30-50% larger than the values in any region currently (2000). Despite known issues, the new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.

  11. Air quality and climate change, Topic 3 of the Model Inter-Comparison Study for Asia Phase III (MICS-Asia III) - Part 1: Overview and model evaluation

    Science.gov (United States)

    Gao, Meng; Han, Zhiwei; Liu, Zirui; Li, Meng; Xin, Jinyuan; Tao, Zhining; Li, Jiawei; Kang, Jeong-Eon; Huang, Kan; Dong, Xinyi; Zhuang, Bingliang; Li, Shu; Ge, Baozhu; Wu, Qizhong; Cheng, Yafang; Wang, Yuesi; Lee, Hyo-Jung; Kim, Cheol-Hee; Fu, Joshua S.; Wang, Tijian; Chin, Mian; Woo, Jung-Hun; Zhang, Qiang; Wang, Zifa; Carmichael, Gregory R.

    2018-04-01

    Topic 3 of the Model Inter-Comparison Study for Asia (MICS-Asia) Phase III examines how online coupled air quality models perform in simulating high aerosol pollution in the North China Plain region during wintertime haze events and evaluates the importance of aerosol radiative and microphysical feedbacks. A comprehensive overview of the MICS-Asia III Topic 3 study design, including descriptions of participating models and model inputs, the experimental designs, and results of model evaluation, are presented. Six modeling groups from China, Korea and the United States submitted results from seven applications of online coupled chemistry-meteorology models. Results are compared to meteorology and air quality measurements, including data from the Campaign on Atmospheric Aerosol Research Network of China (CARE-China) and the Acid Deposition Monitoring Network in East Asia (EANET). The correlation coefficients between the multi-model ensemble mean and the CARE-China observed near-surface air pollutants range from 0.51 to 0.94 (0.51 for ozone and 0.94 for PM2.5) for January 2010. However, large discrepancies exist between simulated aerosol chemical compositions from different models. The coefficient of variation (SD divided by the mean) can reach above 1.3 for sulfate in Beijing and above 1.6 for nitrate and organic aerosols in coastal regions, indicating that these compositions are less consistent from different models. During clean periods, simulated aerosol optical depths (AODs) from different models are similar, but peak values differ during severe haze events, which can be explained by the differences in simulated inorganic aerosol concentrations and the hygroscopic growth efficiency (affected by varied relative humidity). These differences in composition and AOD suggest that future models can be improved by including new heterogeneous or aqueous pathways for sulfate and nitrate formation under hazy conditions, a secondary organic aerosol (SOA) formation chemical

  12. Environmental radioactivity intercomparison measurements

    International Nuclear Information System (INIS)

    2000-01-01

    In the context of the North Cotentin radioecological group set up in 1997 by the Ministry of the Environment and the Ministry of the Secretariat d'Etat a la Sante, the Swiss Federal Office of Public health, a national organization of independent status with respect to nuclear energy, conducted a series of measurements in the north Cotentin in 1998. Some sites proposed by local association 'Angry mothers' were examined in particular. This association has now taken the initiative to organize a large scale international intercomparison, ' North Cotentin 2000', in the vicinity of local nuclear installations. Besides the scientific aspect of the intercomparison, a specific aim of this intercomparison consists in providing to the local population with a real opportunity for direct exchange with participating international teams. The primary concern of the workshop is the determination, by in situ gamma spectrometry, of both natural and artificial concentrations and resulting ambient dose rates at selected marine ( beach) and terrestrial sites. A particular aim of the workshop also is to test the capacity of mobile teams to produce reliable results in the field of low level measurements on trace of special radionuclides (I 129 , Sr 90 , H 3 , C 14 , and alpha emitters) from environmental samples, using both direct ( in situ) and differed ( laboratory methods). an overview of the results obtained will be prepared for the benefit of the public. (N.C.)

  13. The AgMIP GRIDded Crop Modeling Initiative (AgGRID) and the Global Gridded Crop Model Intercomparison (GGCMI)

    Science.gov (United States)

    Elliott, Joshua; Muller, Christoff

    2015-01-01

    Climate change is a significant risk for agricultural production. Even under optimistic scenarios for climate mitigation action, present-day agricultural areas are likely to face significant increases in temperatures in the coming decades, in addition to changes in precipitation, cloud cover, and the frequency and duration of extreme heat, drought, and flood events (IPCC, 2013). These factors will affect the agricultural system at the global scale by impacting cultivation regimes, prices, trade, and food security (Nelson et al., 2014a). Global-scale evaluation of crop productivity is a major challenge for climate impact and adaptation assessment. Rigorous global assessments that are able to inform planning and policy will benefit from consistent use of models, input data, and assumptions across regions and time that use mutually agreed protocols designed by the modeling community. To ensure this consistency, large-scale assessments are typically performed on uniform spatial grids, with spatial resolution of typically 10 to 50 km, over specified time-periods. Many distinct crop models and model types have been applied on the global scale to assess productivity and climate impacts, often with very different results (Rosenzweig et al., 2014). These models are based to a large extent on field-scale crop process or ecosystems models and they typically require resolved data on weather, environmental, and farm management conditions that are lacking in many regions (Bondeau et al., 2007; Drewniak et al., 2013; Elliott et al., 2014b; Gueneau et al., 2012; Jones et al., 2003; Liu et al., 2007; M¨uller and Robertson, 2014; Van den Hoof et al., 2011;Waha et al., 2012; Xiong et al., 2014). Due to data limitations, the requirements of consistency, and the computational and practical limitations of running models on a large scale, a variety of simplifying assumptions must generally be made regarding prevailing management strategies on the grid scale in both the baseline and

  14. Gamma spectroscopy modelization intercomparison of the modelization results using two different codes (MCNP, and Pascalys-mercure)

    International Nuclear Information System (INIS)

    Luneville, L.; Chiron, M.; Toubon, H.; Dogny, S.; Huver, M.; Berger, L.

    2001-01-01

    The research performed in common these last 3 years by the French Atomic Commission CEA, COGEMA and Eurisys Mesures had for main subject the realization of a complete tool of modelization for the largest range of realistic cases, the Pascalys modelization software. The main purpose of the modelization was to calculate the global measurement efficiency, which delivers the most accurate relationship between the photons emitted by the nuclear source in volume, punctual or deposited form and the germanium hyper pure detector, which detects and analyzes the received photons. It has been stated since long time that experimental global measurement efficiency becomes more and more difficult to address especially for complex scene as we can find in decommissioning and dismantling or in case of high activities for which the use of high activity reference sources become difficult to use for both health physics point of view and regulations. The choice of a calculation code is fundamental if accurate modelization is searched. MCNP represents the reference code but its use is long time calculation consuming and then not practicable in line on the field. Direct line-of-sight point kernel code as the French Atomic Commission 3-D analysis Mercure code can represent the practicable compromise between the most accurate MCNP reference code and the realistic performances needed in modelization. The comparison between the results of Pascalys-Mercure and MCNP code taking in account the last improvements of Mercure in the low energy range where the most important errors can occur, is presented in this paper, Mercure code being supported in line by the recent Pascalys 3-D modelization scene software. The incidence of the intrinsic efficiency of the Germanium detector is also approached for the total efficiency of measurement. (authors)

  15. Intercomparison between CMIP5 model and MODIS satellite-retrieved data of aerosol optical depth, cloud fraction, and cloud-aerosol interactions

    Science.gov (United States)

    Sockol, Alyssa; Small Griswold, Jennifer D.

    2017-08-01

    Aerosols are a critical component of the Earth's atmosphere and can affect the climate of the Earth through their interactions with solar radiation and clouds. Cloud fraction (CF) and aerosol optical depth (AOD) at 550 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used with analogous cloud and aerosol properties from Historical Phase 5 of the Coupled Model Intercomparison Project (CMIP5) model runs that explicitly include anthropogenic aerosols and parameterized cloud-aerosol interactions. The models underestimate AOD by approximately 15% and underestimate CF by approximately 10% overall on a global scale. A regional analysis is then used to evaluate model performance in two regions with known biomass burning activity and absorbing aerosol (South America (SAM) and South Africa (SAF)). In SAM, the models overestimate AOD by 4.8% and underestimate CF by 14%. In SAF, the models underestimate AOD by 35% and overestimate CF by 13.4%. Average annual cycles show that the monthly timing of AOD peaks closely match satellite data in both SAM and SAF for all except the Community Atmosphere Model 5 and Geophysical Fluid Dynamics Laboratory (GFDL) models. Monthly timing of CF peaks closely match for all models (except GFDL) for SAM and SAF. Sorting monthly averaged 2° × 2.5° model or MODIS CF as a function of AOD does not result in the previously observed "boomerang"-shaped CF versus AOD relationship characteristic of regions with absorbing aerosols from biomass burning. Cloud-aerosol interactions, as observed using daily (or higher) temporal resolution data, are not reproducible at the spatial or temporal resolution provided by the CMIP5 models.

  16. Representative Agricultural Pathways: A Trans-Disciplinary Approach to Agricultural Model Inter-comparison, Improvement, Climate Impact Assessment and Stakeholder Engagement

    Science.gov (United States)

    Antle, J. M.; Valdivia, R. O.; Claessens, L.; Nelson, G. C.; Rosenzweig, C.; Ruane, A. C.; Vervoort, J.

    2013-12-01

    The global change research community has recognized that new pathway and scenario concepts are needed to implement impact and vulnerability assessment that is logically consistent across local, regional and global scales. For impact and vulnerability assessment, new socio-economic pathway and scenario concepts are being developed. Representative Agricultural Pathways (RAPs) are designed to extend global pathways to provide the detail needed for global and regional assessment of agricultural systems. In addition, research by the Agricultural Model Inter-comparison and Improvement Project (AgMIP) shows that RAPs provide a powerful way to engage stakeholders in climate-related research throughout the research process and in communication of research results. RAPs are based on the integrated assessment framework developed by AgMIP. This framework shows that both bio-physical and socio-economic drivers are essential components of agricultural pathways and logically precede the definition of adaptation and mitigation scenarios that embody associated capabilities and challenges. This approach is based on a trans-disciplinary process for designing pathways and then translating them into parameter sets for bio-physical and economic models that are components of agricultural integrated assessments of climate impact, adaptation and mitigation. RAPs must be designed to be part of a logically consistent set of drivers and outcomes from global to regional and local. Global RAPs are designed to be consistent with higher-level global socio-economic pathways, but add key agricultural drivers such as agricultural growth trends that are not specified in more general pathways, as illustrated in a recent inter-comparison of global agricultural models. To create pathways at regional or local scales, further detail is needed. At this level, teams of scientists and other experts with knowledge of the agricultural systems and regions work together through a step-wise process. Experiences

  17. Assessing radiation impact at a protected coastal sand dune site: an intercomparison of models for estimating the radiological exposure of non-human biota

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Michael D., E-mail: mwood@liv.ac.u [Institute for Sustainable Water Integrated Management and Ecosystem Research (SWIMMER), Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom); School of Biological Sciences, Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom); Beresford, Nicholas A.; Barnett, Catherine L. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, Lancashire LA1 4AP (United Kingdom); Copplestone, David [Environment Agency, PO Box 12, Richard Fairclough House, Knutsford Road, Latchford, Warrington, Cheshire WA4 1HG (United Kingdom); Leah, Richard T. [Institute for Sustainable Water Integrated Management and Ecosystem Research (SWIMMER), Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom); School of Biological Sciences, Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom)

    2009-12-15

    This paper presents the application of three publicly available biota dose assessment models (the ERICA Tool, R and D128/SP1a and RESRAD-BIOTA) to an assessment of the Drigg coastal sand dunes. Using measured {sup 90}Sr, {sup 99}Tc, {sup 137}Cs, {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am activity concentrations in sand dune soil, activity concentration and dose rate predictions are made for a range of organisms including amphibians, birds, invertebrates, mammals, reptiles, plants and fungi. Predicted biota activity concentrations are compared to measured data where available. The main source of variability in the model predictions is the transfer parameters used and it is concluded that developing the available transfer databases should be a focus of future research effort. The value of taking an informed user approach to investigate the way in which models may be expected to be applied in practice is highlighted and a strategy for the future development of intercomparison exercises is presented.

  18. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    Energy Technology Data Exchange (ETDEWEB)

    Klein, S A; McCoy, R B; Morrison, H; Ackerman, A; Avramov, A; deBoer, G; Chen, M; Cole, J; DelGenio, A; Golaz, J; Hashino, T; Harrington, J; Hoose, C; Khairoutdinov, M; Larson, V; Liu, X; Luo, Y; McFarquhar, G; Menon, S; Neggers, R; Park, S; Poellot, M; von Salzen, K; Schmidt, J; Sednev, I; Shipway, B; Shupe, M; Spangenberg, D; Sud, Y; Turner, D; Veron, D; Falk, M; Foster, M; Fridlind, A; Walker, G; Wang, Z; Wolf, A; Xie, S; Xu, K; Yang, F; Zhang, G

    2008-02-27

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The observed liquid water path of around 160 g m{sup -2} was about two-thirds of the adiabatic value and much greater than the mass of ice crystal precipitation which when integrated from the surface to cloud top was around 15 g m{sup -2}. The simulations were performed by seventeen single-column models (SCMs) and nine cloud-resolving models (CRMs). While the simulated ice water path is generally consistent with the observed values, the median SCM and CRM liquid water path is a factor of three smaller than observed. Results from a sensitivity study in which models removed ice microphysics indicate that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this general underestimate, the simulated liquid and ice water paths of several models are consistent with the observed values. Furthermore, there is some evidence that models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter is also present. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics. This case study, which has been well observed from both aircraft and ground-based remote sensors, could be a benchmark for model simulations of mixed-phase clouds.

  19. Evaluation of Preindustrial to Present-day Black Carbon and its Albedo Forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Lamarque, J.-F.; Flanner, M. G.; Jiao, C.; Shindell, Drew; Berntsen, T.; Bisiauxs, M.; Cao, J.; Collins, W. J.; Curran, M.; Edwards, R.; Faluvegi, G.; Ghan, Steven J.; Horowitz, L.; McConnell, J.R.; Ming, J.; Myhre, G.; Nagashima, T.; Naik, Vaishali; Rumbold, S.; Skeie, R. B.; Sudo, K.; Takemura, T.; Thevenon, F.; Xu, B.; Yoon, Jin-Ho

    2013-03-05

    As a part of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), we evaluate the historical black carbon (BC) aerosols simulated by 8 ACCMIP models against the observations including 12 ice core records, a long-term surface mass concentrations and recent Arctic BC snowpack measurements. We also estimate BC albedo forcing by performing additional simulations using the NCAR Community Land and Sea-Ice model 4 with prescribed meteorology from 1996-2000, which includes the SNICAR BC-snow model. We evaluated the vertical profile of BC snow concentrations from these offline simulations to using recent BC snowpack measurements. Despite using the same BC emissions, global BC burden differs by approximately a factor of 3 among models due to the differences in aerosol removal parameterizations and simulated meteorology among models; 34 Gg to 103 Gg in 1850 and 82 Gg to 315 Gg in 2000. However,models agree well on 2.5~3 times increase in the global BC burden from preindustrial to present-day, which matches with the 2.5 times increase in BC emissions. We find a large model diversity at both NH and SH high latitude regions for BC burden and at SH high latitude regions for deposition fluxes. The ACCMIP simulations match the observed BC mass concentrations well in Europe and North America except at Jungfrauch and Ispra. However, the models fail to capture the Arctic BC seasonality due tosevere underestimations during winter and spring. Compared to recent snowpack measurements, the simulated vertically resolved BC snow concentrations are, on average, within a factor of 2-3 of observations except for Greenland and Arctic Ocean. However, model and observation differ widely due to missing interannual variations in emissions and possibly due to the choice of the prescribed meteorology period (i.e., 1996-2000).

  20. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Stephen A.; McCoy, Renata B.; Morrison, Hugh; Ackerman, Andrew S.; Avramov, Alexander; de Boer, Gijs; Chen, Mingxuan; Cole, Jason N.S.; Del Genio, Anthony D.; Falk, Michael; Foster, Michael J.; Fridlind, Ann; Golaz, Jean-Christophe; Hashino, Tempei; Harrington, Jerry Y.; Hoose, Corinna; Khairoutdinov, Marat F.; Larson, Vincent E.; Liu, Xiaohong; Luo, Yali; McFarquhar, Greg M.; Menon, Surabi; Neggers, Roel A. J.; Park, Sungsu; Poellot, Michael R.; Schmidt, Jerome M.; Sednev, Igor; Shipway, Ben J.; Shupe, Matthew D.; Spangenberg, Douglas A.; Sud, Yogesh C.; Turner, David D.; Veron, Dana E.; von Salzen, Knut; Walker, Gregory K.; Wang, Zhien; Wolf, Audrey B.; Xie, Shaocheng; Xu, Kuan-Man; Yang, Fanglin; Zhang, Gong

    2009-02-02

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The observed average liquid water path of around 160 g m{sup -2} was about two-thirds of the adiabatic value and much greater than the average mass of ice crystal precipitation which when integrated from the surface to cloud top was around 15 g m{sup -2}. The simulations were performed by seventeen single-column models (SCMs) and nine cloud-resolving models (CRMs). While the simulated ice water path is generally consistent with the observed values, the median SCM and CRM liquid water path is a factor of three smaller than observed. Results from a sensitivity study in which models removed ice microphysics suggest that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this general underestimate, the simulated liquid and ice water paths of several models are consistent with the observed values. Furthermore, there is evidence that models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter is also present. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics.

  1. Tritium in the food chain. Intercomparison of model predictions of contamination in soil, crops, milk and beef after a short exposure to tritiated water vapour in air

    International Nuclear Information System (INIS)

    Barry, P.

    1996-09-01

    Future fusion reactors using tritium as fuel will contain large inventories of the gas. The possibility that a significant fraction of an inventory may accidentally escape into the atmosphere from this and other potential sources such as tritium handling facilities and some fission reactors e g, PWRs has to be recognized and its potential impact on local human populations and biota assessed. Tritium gas is relatively inert chemically and of low radiotoxicity but it is readily oxidized by soil organisms to the mixed oxide, HTO or tritiated water. In this form it is highly mobile, strongly reactive biologically and much more toxic. Models of how tritiated water vapour is transported through the biosphere to foodstuffs important to man are essential components of such an assessment and it is important to test the models for their suitability when used for this purpose. To evaluate such models, access to experimental measurements made after actual releases are needed. There have however, been very few accidental releases of tritiated water to the atmosphere and the experimental findings of those that have occurred have been used to develop the models under test. Models must nevertheless be evaluated before their predictions can be used to decide the acceptability or otherwise of designing and operating major nuclear facilities. To fulfil this need a model intercomparison study was carried out for a hypothetical release scenario. The study described in this report is a contribution to the development of model evaluation procedures in general as well as a description of the results of applying these procedures to the particular case of models of HTO transport in the biosphere which are currently in use or being developed. The study involved eight modelers using seven models in as many countries. In the scenario farmland was exposed to 1E10 Bq d/m 3 of HTO in air during 1 hour starting at midnight in one case and at 10.00 a.m. in the other, 30 days before harvest of crops

  2. Tritium in the food chain. Intercomparison of model predictions of contamination in soil, crops, milk and beef after a short exposure to tritiated water vapour in air

    Energy Technology Data Exchange (ETDEWEB)

    Barry, P. [PJS Barry (Canada)] [and others

    1996-09-01

    Future fusion reactors using tritium as fuel will contain large inventories of the gas. The possibility that a significant fraction of an inventory may accidentally escape into the atmosphere from this and other potential sources such as tritium handling facilities and some fission reactors e g, PWRs has to be recognized and its potential impact on local human populations and biota assessed. Tritium gas is relatively inert chemically and of low radiotoxicity but it is readily oxidized by soil organisms to the mixed oxide, HTO or tritiated water. In this form it is highly mobile, strongly reactive biologically and much more toxic. Models of how tritiated water vapour is transported through the biosphere to foodstuffs important to man are essential components of such an assessment and it is important to test the models for their suitability when used for this purpose. To evaluate such models, access to experimental measurements made after actual releases are needed. There have however, been very few accidental releases of tritiated water to the atmosphere and the experimental findings of those that have occurred have been used to develop the models under test. Models must nevertheless be evaluated before their predictions can be used to decide the acceptability or otherwise of designing and operating major nuclear facilities. To fulfil this need a model intercomparison study was carried out for a hypothetical release scenario. The study described in this report is a contribution to the development of model evaluation procedures in general as well as a description of the results of applying these procedures to the particular case of models of HTO transport in the biosphere which are currently in use or being developed. The study involved eight modelers using seven models in as many countries. In the scenario farmland was exposed to 1E10 Bq d/m{sup 3} of HTO in air during 1 hour starting at midnight in one case and at 10.00 a.m. in the other, 30 days before harvest of

  3. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part II: Multi-layered cloud

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, H; McCoy, R B; Klein, S A; Xie, S; Luo, Y; Avramov, A; Chen, M; Cole, J; Falk, M; Foster, M; Genio, A D; Harrington, J; Hoose, C; Khairoutdinov, M; Larson, V; Liu, X; McFarquhar, G; Poellot, M; Shipway, B; Shupe, M; Sud, Y; Turner, D; Veron, D; Walker, G; Wang, Z; Wolf, A; Xu, K; Yang, F; Zhang, G

    2008-02-27

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a deep, multi-layered, mixed-phase cloud system observed during the ARM Mixed-Phase Arctic Cloud Experiment. This cloud system was associated with strong surface turbulent sensible and latent heat fluxes as cold air flowed over the open Arctic Ocean, combined with a low pressure system that supplied moisture at mid-level. The simulations, performed by 13 single-column and 4 cloud-resolving models, generally overestimate the liquid water path and strongly underestimate the ice water path, although there is a large spread among the models. This finding is in contrast with results for the single-layer, low-level mixed-phase stratocumulus case in Part I of this study, as well as previous studies of shallow mixed-phase Arctic clouds, that showed an underprediction of liquid water path. The overestimate of liquid water path and underestimate of ice water path occur primarily when deeper mixed-phase clouds extending into the mid-troposphere were observed. These results suggest important differences in the ability of models to simulate Arctic mixed-phase clouds that are deep and multi-layered versus shallow and single-layered. In general, models with a more sophisticated, two-moment treatment of the cloud microphysics produce a somewhat smaller liquid water path that is closer to observations. The cloud-resolving models tend to produce a larger cloud fraction than the single-column models. The liquid water path and especially the cloud fraction have a large impact on the cloud radiative forcing at the surface, which is dominated by the longwave flux for this case.

  4. Constraining surface emissions of air pollutants using inverse modelling: method intercomparison and a new two-step two-scale regularization approach

    Energy Technology Data Exchange (ETDEWEB)

    Saide, Pablo (CGRER, Center for Global and Regional Environmental Research, Univ. of Iowa, Iowa City, IA (United States)), e-mail: pablo-saide@uiowa.edu; Bocquet, Marc (Universite Paris-Est, CEREA Joint Laboratory Ecole des Ponts ParisTech and EDF RandD, Champs-sur-Marne (France); INRIA, Paris Rocquencourt Research Center (France)); Osses, Axel (Departamento de Ingeniera Matematica, Universidad de Chile, Santiago (Chile); Centro de Modelamiento Matematico, UMI 2807/Universidad de Chile-CNRS, Santiago (Chile)); Gallardo, Laura (Centro de Modelamiento Matematico, UMI 2807/Universidad de Chile-CNRS, Santiago (Chile); Departamento de Geofisica, Universidad de Chile, Santiago (Chile))

    2011-07-15

    When constraining surface emissions of air pollutants using inverse modelling one often encounters spurious corrections to the inventory at places where emissions and observations are colocated, referred to here as the colocalization problem. Several approaches have been used to deal with this problem: coarsening the spatial resolution of emissions; adding spatial correlations to the covariance matrices; adding constraints on the spatial derivatives into the functional being minimized; and multiplying the emission error covariance matrix by weighting factors. Intercomparison of methods for a carbon monoxide inversion over a city shows that even though all methods diminish the colocalization problem and produce similar general patterns, detailed information can greatly change according to the method used ranging from smooth, isotropic and short range modifications to not so smooth, non-isotropic and long range modifications. Poisson (non-Gaussian) and Gaussian assumptions both show these patterns, but for the Poisson case the emissions are naturally restricted to be positive and changes are given by means of multiplicative correction factors, producing results closer to the true nature of emission errors. Finally, we propose and test a new two-step, two-scale, fully Bayesian approach that deals with the colocalization problem and can be implemented for any prior density distribution

  5. Impacts of historic and projected land-cover, land-use, and land-management change on carbon and water fluxes: The Land Use Model Intercomparison Project (LUMIP)

    Science.gov (United States)

    Lawrence, D. M.; Lombardozzi, D. L.; Lawrence, P.; Hurtt, G. C.

    2017-12-01

    Human land-use activities have resulted in large changes to the Earth surface, with resulting implications for climate. In the future, land-use activities are likely to intensify to meet growing demands for food, fiber, and energy. The Land Use Model Intercomparison Project (LUMIP) aims to further advance understanding of the broad question of impacts of land-use and land-cover change (LULCC) as well as more detailed science questions to get at process-level attribution, uncertainty, and data requirements in more depth and sophistication than possible in a multi-model context to date. LUMIP is multi-faceted and aims to advance our understanding of land-use change from several perspectives. In particular, LUMIP includes a factorial set of land-only simulations that differ from each other with respect to the specific treatment of land use or land management (e.g., irrigation active or not, crop fertilization active or not, wood harvest on or not), or in terms of prescribed climate. This factorial series of experiments serves several purposes and is designed to provide a detailed assessment of how the specification of land-cover change and land management affects the carbon, water, and energy cycle response to land-use change. The potential analyses that are possible through this set of experiments are vast. For example, comparing a control experiment with all land management active to an experiment with no irrigation allows a multi-model assessment of whether or not the increasing use of irrigation during the 20th century is likely to have significantly altered trends of regional water and energy fluxes (and therefore climate) and/or crop yield and carbon fluxes in agricultural regions. Here, we will present preliminary results from the factorial set of experiments utilizing the Community Land Model (CLM5). The analyses presented here will help guide multi-model analyses once the full set of LUMIP simulations are available.

  6. Composition Changes After the "Halloween" Solar Proton Event: The High-Energy Particle Precipitation in the Atmosphere (HEPPA) Model Versus MIPAS Data Intercomparison Study

    Science.gov (United States)

    Funke, B.; Baumgaertner, A.; Calisto, M.; Egorova, T.; Jackman, C. H.; Kieser, J.; Krivolutsky, A.; Lopez-Puertas, M.; Marsh. D. R.; Reddmann, T.; hide

    2010-01-01

    analysis of chlorine species perturbations has shown that the encountered differences between models and observations, particularly the underestimation of observed ClONO2 enhancements, are related to a smaller availability of ClO in the polar night region already before the SPE. In general, the intercomparison has demonstrated that differences in the meteorology and/or initial state of the atmosphere in the simulations causes a relevant variability of the model results, even on a short timescale of only a few days.

  7. The sensitivity of the Arctic sea ice to orbitally induced insolation changes: a study of the mid-Holocene Paleoclimate Modelling Intercomparison Project 2 and 3 simulations

    Directory of Open Access Journals (Sweden)

    M. Berger

    2013-04-01

    Full Text Available In the present work the Arctic sea ice in the mid-Holocene and the pre-industrial climates are analysed and compared on the basis of climate-model results from the Paleoclimate Modelling Intercomparison Project phase 2 (PMIP2 and phase 3 (PMIP3. The PMIP3 models generally simulate smaller and thinner sea-ice extents than the PMIP2 models both for the pre-industrial and the mid-Holocene climate. Further, the PMIP2 and PMIP3 models all simulate a smaller and thinner Arctic summer sea-ice cover in the mid-Holocene than in the pre-industrial control climate. The PMIP3 models also simulate thinner winter sea ice than the PMIP2 models. The winter sea-ice extent response, i.e. the difference between the mid-Holocene and the pre-industrial climate, varies among both PMIP2 and PMIP3 models. Approximately one half of the models simulate a decrease in winter sea-ice extent and one half simulates an increase. The model-mean summer sea-ice extent is 11 % (21 % smaller in the mid-Holocene than in the pre-industrial climate simulations in the PMIP2 (PMIP3. In accordance with the simple model of Thorndike (1992, the sea-ice thickness response to the insolation change from the pre-industrial to the mid-Holocene is stronger in models with thicker ice in the pre-industrial climate simulation. Further, the analyses show that climate models for which the Arctic sea-ice responses to increasing atmospheric CO2 concentrations are similar may simulate rather different sea-ice responses to the change in solar forcing between the mid-Holocene and the pre-industrial. For two specific models, which are analysed in detail, this difference is found to be associated with differences in the simulated cloud fractions in the summer Arctic; in the model with a larger cloud fraction the effect of insolation change is muted. A sub-set of the mid-Holocene simulations in the PMIP ensemble exhibit open water off the north-eastern coast of Greenland in summer, which can provide a fetch

  8. The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) Contribution to CMIP6: Investigation of Sea-Level and Ocean Climate Change in Response to CO2 Forcing

    Science.gov (United States)

    Gregory, Jonathan M.; Bouttes, Nathaelle; Griffies, Stephen M.; Haak, Helmuth; Hurlin, William J.; Jungclaus, Johann; Kelley, Maxwell; Lee, Warren G.; Marshall, John; Romanou, Anastasia; hide

    2016-01-01

    The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) aims to investigate the spread in simulations of sea-level and ocean climate change in response to CO2 forcing by atmosphere-ocean general circulation models (AOGCMs). It is particularly motivated by the uncertainties in projections of ocean heat uptake, global-mean sealevel rise due to thermal expansion and the geographical patterns of sea-level change due to ocean density and circulation change. FAFMIP has three tier-1 experiments, in which prescribed surface flux perturbations of momentum, heat and freshwater respectively are applied to the ocean in separate AOGCM simulations. All other conditions are as in the pre-industrial control. The prescribed fields are typical of pattern and magnitude of changes in these fluxes projected by AOGCMs for doubled CO2 concentration. Five groups have tested the experimental design with existing AOGCMs. Their results show diversity in the pattern and magnitude of changes, with some common qualitative features. Heat and water flux perturbation cause the dipole in sea-level change in the North Atlantic, while momentum and heat flux perturbation cause the gradient across the Antarctic Circumpolar Current. The Atlantic meridional overturning circulation (AMOC) declines in response to the heat flux perturbation, and there is a strong positive feedback on this effect due to the consequent cooling of sea-surface temperature in the North Atlantic, which enhances the local heat input to the ocean. The momentum and water flux perturbations do not substantially affect the AMOC. Heat is taken up largely as a passive tracer in the Southern Ocean, which is the region of greatest heat input, while the weakening of the AMOC causes redistribution of heat towards lower latitudes. Future analysis of these and other phenomena with the wider range of CMIP6 FAFMIP AOGCMs will benefit from new diagnostics of temperature and salinity tendencies, which will enable investigation of the model

  9. Assessing the impacts of 1.5°C of global warming - The Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) approach

    Science.gov (United States)

    Frieler, Katja; Warszawski, Lila; Zhao, Fang

    2017-04-01

    In Paris, France, December 2015 the Conference of Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC) invited the IPCC to provide a "special report in 2018 on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways". In Nairobi, Kenya, April 2016 the IPCC panel accepted the invitation. Here we describe the model simulations planned within the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) to address the request by providing tailored cross-sectoral consistent impacts projections. The protocol is designed to allow for 1) a separation of the impacts of the historical warming starting from pre-industrial conditions from other human drivers such as historical land use changes (based on pre-industrial and historical impact model simulations), 2) a quantification of the effects of an additional warming to 1.5°C including a potential overshoot and long term effects up to 2300 in comparison to a no-mitigation scenario (based on the low emissions Representative Concentration Pathway RCP2.6 and a no-mitigation scenario RCP6.0) keeping socio-economic conditions fixed at year 2005 levels, and 3) an assessment of the climate effects based on the same climate scenarios but accounting for parallel changes in socio-economic conditions following the middle of the road Shared Socioeconomic Pathway (SSP2) and differential bio-energy requirements associated with the transformation of the energy system to reach RCP2.6 compared to RCP6.0. To provide the scientific basis for an aggregation of impacts across sectors and an analysis of cross-sectoral interactions potentially damping or amplifying sectoral impacts the protocol is designed to provide consistent impacts projections across a range of impact models from different sectors (global and regional hydrological models, global gridded crop models, global vegetation models, regional forestry models, global and regional marine

  10. The Community Intercomparison Suite (CIS)

    Science.gov (United States)

    Watson-Parris, Duncan; Schutgens, Nick; Cook, Nick; Kipling, Zak; Kershaw, Phil; Gryspeerdt, Ed; Lawrence, Bryan; Stier, Philip

    2017-04-01

    Earth observations (both remote and in-situ) create vast amounts of data providing invaluable constraints for the climate science community. Efficient exploitation of these complex and highly heterogeneous datasets has been limited however by the lack of suitable software tools, particularly for comparison of gridded and ungridded data, thus reducing scientific productivity. CIS (http://cistools.net) is an open-source, command line tool and Python library which allows the straight-forward quantitative analysis, intercomparison and visualisation of remote sensing, in-situ and model data. The CIS can read gridded and ungridded remote sensing, in-situ and model data - and many other data sources 'out-of-the-box', such as ESA Aerosol and Cloud CCI product, MODIS, Cloud CCI, Cloudsat, AERONET. Perhaps most importantly however CIS also employs a modular plugin architecture to allow for the reading of limitless different data types. Users are able to write their own plugins for reading the data sources which they are familiar with, and share them within the community, allowing all to benefit from their expertise. To enable the intercomparison of this data the CIS provides a number of operations including: the aggregation of ungridded and gridded datasets to coarser representations using a number of different built in averaging kernels; the subsetting of data to reduce its extent or dimensionality; the co-location of two distinct datasets onto a single set of co-ordinates; the visualisation of the input or output data through a number of different plots and graphs; the evaluation of arbitrary mathematical expressions against any number of datasets; and a number of other supporting functions such as a statistical comparison of two co-located datasets. These operations can be performed efficiently on local machines or large computing clusters - and is already available on the JASMIN computing facility. A case-study using the GASSP collection of in-situ aerosol observations

  11. Tropical and Subtropical Cloud Transitions in Weather and Climate Prediction Models: The GCSS/WGNE Pacific Cross-Section Intercomparison (GPCI)

    Science.gov (United States)

    Teixeira, J.; Cardoso, S.; Bonazzola, M.; Cole, J.; DeGenio, A.; DeMott, C.; Franklin, C.; Hannay, C.; Jakob, C.; Jiao, Y.; hide

    2011-01-01

    A model evaluation approach is proposed in which weather and climate prediction models are analyzed along a Pacific Ocean cross section, from the stratocumulus regions off the coast of California, across the shallow convection dominated trade winds, to the deep convection regions of the ITCZ the Global Energy and Water Cycle Experiment Cloud System Study/Working Group on Numerical Experimentation (GCSS/ WGNE) Pacific Cross-Section Intercomparison (GPCI). The main goal of GPCI is to evaluate and help understand and improve the representation of tropical and subtropical cloud processes in weather and climate prediction models. In this paper, a detailed analysis of cloud regime transitions along the cross section from the subtropics to the tropics for the season June July August of 1998 is presented. This GPCI study confirms many of the typical weather and climate prediction model problems in the representation of clouds: underestimation of clouds in the stratocumulus regime by most models with the corresponding consequences in terms of shortwave radiation biases; overestimation of clouds by the 40-yr ECMWF Re-Analysis (ERA-40) in the deep tropics (in particular) with the corresponding impact in the outgoing longwave radiation; large spread between the different models in terms of cloud cover, liquid water path and shortwave radiation; significant differences between the models in terms of vertical cross sections of cloud properties (in particular), vertical velocity, and relative humidity. An alternative analysis of cloud cover mean statistics is proposed where sharp gradients in cloud cover along the GPCI transect are taken into account. This analysis shows that the negative cloud bias of some models and ERA-40 in the stratocumulus regions [as compared to the first International Satellite Cloud Climatology Project (ISCCP)] is associated not only with lower values of cloud cover in these regimes, but also with a stratocumulus-to-cumulus transition that occurs too

  12. Sensitivity of global and regional terrestrial carbon storage to the direct CO2 effect and climate change based on the CMIP5 model intercomparison.

    Science.gov (United States)

    Peng, Jing; Dan, Li; Huang, Mei

    2014-01-01

    Global and regional land carbon storage has been significantly affected by increasing atmospheric CO2 concentration and climate change. Based on fully coupled climate-carbon-cycle simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5), we investigate sensitivities of land carbon storage to rising atmospheric CO2 concentration and climate change over the world and 21 regions during the 130 years. Overall, the simulations suggest that consistently spatial positive effects of the increasing CO2 concentrations on land carbon storage are expressed with a multi-model averaged value of 1.04 PgC per ppm. The stronger positive values are mainly located in the broad areas of temperate and tropical forest, especially in Amazon basin and western Africa. However, large heterogeneity distributed for sensitivities of land carbon storage to climate change. Climate change causes decrease in land carbon storage in most tropics and the Southern Hemisphere. In these regions, decrease in soil moisture (MRSO) and enhanced drought somewhat contribute to such a decrease accompanied with rising temperature. Conversely, an increase in land carbon storage has been observed in high latitude and altitude regions (e.g., northern Asia and Tibet). The model simulations also suggest that global negative impacts of climate change on land carbon storage are predominantly attributed to decrease in land carbon storage in tropics. Although current warming can lead to an increase in land storage of high latitudes of Northern Hemisphere due to elevated vegetation growth, a risk of exacerbated future climate change may be induced due to release of carbon from tropics.

  13. Sensitivity of global and regional terrestrial carbon storage to the direct CO2 effect and climate change based on the CMIP5 model intercomparison.

    Directory of Open Access Journals (Sweden)

    Jing Peng

    Full Text Available Global and regional land carbon storage has been significantly affected by increasing atmospheric CO2 concentration and climate change. Based on fully coupled climate-carbon-cycle simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5, we investigate sensitivities of land carbon storage to rising atmospheric CO2 concentration and climate change over the world and 21 regions during the 130 years. Overall, the simulations suggest that consistently spatial positive effects of the increasing CO2 concentrations on land carbon storage are expressed with a multi-model averaged value of 1.04 PgC per ppm. The stronger positive values are mainly located in the broad areas of temperate and tropical forest, especially in Amazon basin and western Africa. However, large heterogeneity distributed for sensitivities of land carbon storage to climate change. Climate change causes decrease in land carbon storage in most tropics and the Southern Hemisphere. In these regions, decrease in soil moisture (MRSO and enhanced drought somewhat contribute to such a decrease accompanied with rising temperature. Conversely, an increase in land carbon storage has been observed in high latitude and altitude regions (e.g., northern Asia and Tibet. The model simulations also suggest that global negative impacts of climate change on land carbon storage are predominantly attributed to decrease in land carbon storage in tropics. Although current warming can lead to an increase in land storage of high latitudes of Northern Hemisphere due to elevated vegetation growth, a risk of exacerbated future climate change may be induced due to release of carbon from tropics.

  14. Dust Model Intercomparison and Extensive Comparison to Observations in the Western Mediterranean for the Summer 2012 Pre-ChArMEx/TRAQA Campaign

    Science.gov (United States)

    Basart, S.; Dulac, F.; Baldasano, J. M.

    2014-12-01

    The present analysis focuses on the model capability to properly simulate long-range Saharan dust transport for summer 2012 in the Western Mediterranean. In this period, Saharan dust events were numerous as shown by satellite and ground-based remote sensing observations.An exhaustive comparison of model outputs against other models and observations can reveal weaknesses of individual models, provide an assessment of uncertainties in simulating the dust cycle and give additional information on sources for potential model improvement. For this kind of study, multiple and different observations are combined to deliver a detailed idea of the structure and evolution of the dust cloud and the state of the atmosphere at the different stages of the event. The present contribution shows an intercomparison of a set of 7 European regional dust model simulations (NMMB/BSC-Dust, ALADIN, Meso-NH, RegCM, CHIMERE, COSMO/MUSCAT; MOCAGE and BSC-DREAM8b). In this study, the model outputs are compared against a variety of both ground-based and airborne in situ and remote sensing measurements performed during the pre-ChArMEx/TRAQA field campaign which included in particular several AERONET sites, the airborne lidar LNG, sounding with a ULA and with the new balloonborne optical particle counter LOAC showing large particles (>15 µm), the CARAGA network of weekly deposition samples, etc. The models are also compared with satellite aerosol products (including MSG/SEVIRI, MODIS, POLDER and CALIOP), which provide a description of the spatial AOD distribution over the basin. These observational datasets provide a complete set of unusual quantitative constraints for model simulations of this period, combining data on aerosol optical depth, vertical distribution, particle size distribution, deposition flux, and chemical and optical properties. Acknowledgements are addressed to OMP/SEDOO for the ChArMEx data portal and to CNES for balloon operations and funding. The other main sponsors of the

  15. Intercomparison of two BRDF models in the estimation of the directional emissivity in MIR channel from MSG1-SEVIRI data.

    Science.gov (United States)

    Jiang, Geng-Ming; Li, Zhao-Liang

    2008-11-10

    This work intercompared two Bi-directional Reflectance Distribution Function (BRDF) models, the modified Minnaert's model and the RossThick-LiSparse-R model, in the estimation of the directional emissivity in Middle Infra-Red (MIR) channel from the data acquired by the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) onboard the first Meteosat Second Generation (MSG1). The bi-directional reflectances in SEVIRI channel 4 (3.9 microm) were estimated from the combined MIR and Thermal Infra-Red (TIR) data and then were used to estimate the directional emissivity in this channel with aid of the BRDF models. The results show that: (1) Both models can relatively well describe the non-Lambertian reflective behavior of land surfaces in SEVIRI channel 4; (2) The RossThick-LiSparse-R model is better than the modified Minnaert's model in modeling the bi-directional reflectances, and the directional emissivities modeled by the modified Minnaert's model are always lower than the ones obtained by the RossThick-LiSparse-R model with averaged emissivity differences of approximately 0.01 and approximately 0.04 over the vegetated and bare areas, respectively. The use of the RossThick-LiSparse-R model in the estimation of the directional emissivity in MIR channel is recommended.

  16. Intercomparisons of Prognostic, Diagnostic, and Inversion Modeling Approaches for Estimation of Net Ecosystem Exchange over the Pacific Northwest Region

    Science.gov (United States)

    Turner, D. P.; Jacobson, A. R.; Nemani, R. R.

    2013-12-01

    The recent development of large spatially-explicit datasets for multiple variables relevant to monitoring terrestrial carbon flux offers the opportunity to estimate the terrestrial land flux using several alternative, potentially complimentary, approaches. Here we developed and compared regional estimates of net ecosystem exchange (NEE) over the Pacific Northwest region of the U.S. using three approaches. In the prognostic modeling approach, the process-based Biome-BGC model was driven by distributed meteorological station data and was informed by Landsat-based coverages of forest stand age and disturbance regime. In the diagnostic modeling approach, the quasi-mechanistic CFLUX model estimated net ecosystem production (NEP) by upscaling eddy covariance flux tower observations. The model was driven by distributed climate data and MODIS FPAR (the fraction of incident PAR that is absorbed by the vegetation canopy). It was informed by coarse resolution (1 km) data about forest stand age. In both the prognostic and diagnostic modeling approaches, emissions estimates for biomass burning, harvested products, and river/stream evasion were added to model-based NEP to get NEE. The inversion model (CarbonTracker) relied on observations of atmospheric CO2 concentration to optimize prior surface carbon flux estimates. The Pacific Northwest is heterogeneous with respect to land cover and forest management, and repeated surveys of forest inventory plots support the presence of a strong regional carbon sink. The diagnostic model suggested a stronger carbon sink than the prognostic model, and a much larger sink that the inversion model. The introduction of Landsat data on disturbance history served to reduce uncertainty with respect to regional NEE in the diagnostic and prognostic modeling approaches. The FPAR data was particularly helpful in capturing the seasonality of the carbon flux using the diagnostic modeling approach. The inversion approach took advantage of a global

  17. nonlinMIP contribution to CMIP6: model intercomparison project for non-linear mechanisms: physical basis, experimental design and analysis principles (v1.0

    Directory of Open Access Journals (Sweden)

    P. Good

    2016-11-01

    Full Text Available nonlinMIP provides experiments that account for state-dependent regional and global climate responses. The experiments have two main applications: (1 to focus understanding of responses to CO2 forcing on states relevant to specific policy or scientific questions (e.g. change under low-forcing scenarios, the benefits of mitigation, or from past cold climates to the present day, or (2 to understand the state dependence (non-linearity of climate change – i.e. why doubling the forcing may not double the response. State dependence (non-linearity of responses can be large at regional scales, with important implications for understanding mechanisms and for general circulation model (GCM emulation techniques (e.g. energy balance models and pattern-scaling methods. However, these processes are hard to explore using traditional experiments, which explains why they have had so little attention in previous studies. Some single model studies have established novel analysis principles and some physical mechanisms. There is now a need to explore robustness and uncertainty in such mechanisms across a range of models (point 2 above, and, more broadly, to focus work on understanding the response to CO2 on climate states relevant to specific policy/science questions (point 1. nonlinMIP addresses this using a simple, small set of CO2-forced experiments that are able to separate linear and non-linear mechanisms cleanly, with a good signal-to-noise ratio – while being demonstrably traceable to realistic transient scenarios. The design builds on the CMIP5 (Coupled Model Intercomparison Project Phase 5 and CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima protocols, and is centred around a suite of instantaneous atmospheric CO2 change experiments, with a ramp-up–ramp-down experiment to test traceability to gradual forcing scenarios. In all cases the models are intended to be used with CO2 concentrations rather than CO2 emissions as the input. The

  18. nonlinMIP contribution to CMIP6: model intercomparison project for non-linear mechanisms: physical basis, experimental design and analysis principles (v1.0)

    Science.gov (United States)

    Good, Peter; Andrews, Timothy; Chadwick, Robin; Dufresne, Jean-Louis; Gregory, Jonathan M.; Lowe, Jason A.; Schaller, Nathalie; Shiogama, Hideo

    2016-11-01

    nonlinMIP provides experiments that account for state-dependent regional and global climate responses. The experiments have two main applications: (1) to focus understanding of responses to CO2 forcing on states relevant to specific policy or scientific questions (e.g. change under low-forcing scenarios, the benefits of mitigation, or from past cold climates to the present day), or (2) to understand the state dependence (non-linearity) of climate change - i.e. why doubling the forcing may not double the response. State dependence (non-linearity) of responses can be large at regional scales, with important implications for understanding mechanisms and for general circulation model (GCM) emulation techniques (e.g. energy balance models and pattern-scaling methods). However, these processes are hard to explore using traditional experiments, which explains why they have had so little attention in previous studies. Some single model studies have established novel analysis principles and some physical mechanisms. There is now a need to explore robustness and uncertainty in such mechanisms across a range of models (point 2 above), and, more broadly, to focus work on understanding the response to CO2 on climate states relevant to specific policy/science questions (point 1). nonlinMIP addresses this using a simple, small set of CO2-forced experiments that are able to separate linear and non-linear mechanisms cleanly, with a good signal-to-noise ratio - while being demonstrably traceable to realistic transient scenarios. The design builds on the CMIP5 (Coupled Model Intercomparison Project Phase 5) and CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima) protocols, and is centred around a suite of instantaneous atmospheric CO2 change experiments, with a ramp-up-ramp-down experiment to test traceability to gradual forcing scenarios. In all cases the models are intended to be used with CO2 concentrations rather than CO2 emissions as the input. The understanding

  19. Intercomparison of regional-scale hydrological models and climate change impacts projected for 12 large river basins worldwide—a synthesis

    Science.gov (United States)

    Krysanova, Valentina; Vetter, Tobias; Eisner, Stephanie; Huang, Shaochun; Pechlivanidis, Ilias; Strauch, Michael; Gelfan, Alexander; Kumar, Rohini; Aich, Valentin; Arheimer, Berit; Chamorro, Alejandro; van Griensven, Ann; Kundu, Dipangkar; Lobanova, Anastasia; Mishra, Vimal; Plötner, Stefan; Reinhardt, Julia; Seidou, Ousmane; Wang, Xiaoyan; Wortmann, Michel; Zeng, Xiaofan; Hattermann, Fred F.

    2017-10-01

    An intercomparison of climate change impacts projected by nine regional-scale hydrological models for 12 large river basins on all continents was performed, and sources of uncertainty were quantified in the framework of the ISIMIP project. The models ECOMAG, HBV, HYMOD, HYPE, mHM, SWAT, SWIM, VIC and WaterGAP3 were applied in the following basins: Rhine and Tagus in Europe, Niger and Blue Nile in Africa, Ganges, Lena, Upper Yellow and Upper Yangtze in Asia, Upper Mississippi, MacKenzie and Upper Amazon in America, and Darling in Australia. The model calibration and validation was done using WATCH climate data for the period 1971-2000. The results, evaluated with 14 criteria, are mostly satisfactory, except for the low flow. Climate change impacts were analyzed using projections from five global climate models under four representative concentration pathways. Trends in the period 2070-2099 in relation to the reference period 1975-2004 were evaluated for three variables: the long-term mean annual flow and high and low flow percentiles Q 10 and Q 90, as well as for flows in three months high- and low-flow periods denoted as HF and LF. For three river basins: the Lena, MacKenzie and Tagus strong trends in all five variables were found (except for Q 10 in the MacKenzie); trends with moderate certainty for three to five variables were confirmed for the Rhine, Ganges and Upper Mississippi; and increases in HF and LF were found for the Upper Amazon, Upper Yangtze and Upper Yellow. The analysis of projected streamflow seasonality demonstrated increasing streamflow volumes during the high-flow period in four basins influenced by monsoonal precipitation (Ganges, Upper Amazon, Upper Yangtze and Upper Yellow), an amplification of the snowmelt flood peaks in the Lena and MacKenzie, and a substantial decrease of discharge in the Tagus (all months). The overall average fractions of uncertainty for the annual mean flow projections in the multi-model ensemble applied for all basins

  20. Intercomparison of Environmental Nuclear Radiation Measuring

    Institute of Scientific and Technical Information of China (English)

    GAO; Fei; NI; Ning; HOU; Jin-bing; SONG; Ming-zhe

    2015-01-01

    In 2015,Radiation Metrology Division of China Institute of Atomic Energy organized an environmental monitoring of nuclear radiation measuring intercomparison,and 9laboratories attended.The intercomparison included environmental level dosemeters and protection level

  1. Intercomparison of radiocarbon bomb pulse and 210Pb age models. A study in a peat bog core from North Poland

    International Nuclear Information System (INIS)

    Piotrowska, Natalia; Vleeschouwer, Francois De; Sikorski, Jaroslaw; Pawlyta, Jacek; Fagel, Nathalie; Roux, Gael Le; Pazdur, Anna

    2010-01-01

    Radiocarbon and 210 Pb were measured on the uppermost 40 cm of a Wardenaar peat core retrieved from a Baltic raised bog at Slowinskie Blota (Pomerania, North Poland). This site is the subject of ongoing multiproxy studies covering the last 1300 years. Radiocarbon age model was constructed on the basis of 14 AMS dates obtained on selected Sphagnum spp. fragments, with use of P S equence tool. We present here a comparison of this model with the age model obtained using CRS model classically applied to 210 Pb measurements.

  2. Intercomparison of radiocarbon bomb pulse and 210Pb age models. A study in a peat bog core from North Poland

    Science.gov (United States)

    Piotrowska, Natalia; De Vleeschouwer, François; Sikorski, Jarosław; Pawlyta, Jacek; Fagel, Nathalie; Le Roux, Gaël; Pazdur, Anna

    2010-04-01

    Radiocarbon and 210Pb were measured on the uppermost 40 cm of a Wardenaar peat core retrieved from a Baltic raised bog at Słowińskie Błota (Pomerania, North Poland). This site is the subject of ongoing multiproxy studies covering the last 1300 years. Radiocarbon age model was constructed on the basis of 14 AMS dates obtained on selected Sphagnum spp. fragments, with use of P_Sequence tool. We present here a comparison of this model with the age model obtained using CRS model classically applied to 210Pb measurements.

  3. Changes in atmospheric variability in a glacial climate and the impacts on proxy data: a model intercomparison

    Directory of Open Access Journals (Sweden)

    F. S. R. Pausata

    2009-09-01

    Full Text Available Using four different climate models, we investigate sea level pressure variability in the extratropical North Atlantic in the preindustrial climate (1750 AD and at the Last Glacial Maximum (LGM, 21 kyrs before present in order to understand how changes in atmospheric circulation can affect signals recorded in climate proxies.

    In general, the models exhibit a significant reduction in interannual variance of sea level pressure at the LGM compared to pre-industrial simulations and this reduction is concentrated in winter. For the preindustrial climate, all models feature a similar leading mode of sea level pressure variability that resembles the leading mode of variability in the instrumental record: the North Atlantic Oscillation (NAO. In contrast, the leading mode of sea level pressure variability at the LGM is model dependent, but in each model different from that in the preindustrial climate. In each model, the leading (NAO-like mode of variability explains a smaller fraction of the variance and also less absolute variance at the LGM than in the preindustrial climate.

    The models show that the relationship between atmospheric variability and surface climate (temperature and precipitation variability change in different climates. Results are model-specific, but indicate that proxy signals at the LGM may be misinterpreted if changes in the spatial pattern and seasonality of surface climate variability are not taken into account.

  4. A single-column model intercomparison on the stratocumulus representation in present-day and future climate

    NARCIS (Netherlands)

    Dal Gesso, S.; Van der Dussen, J.J.; Siebesma, A.P.; De Roode, S.R.; Boutle, I.A.; Kamae, Y.; Roehrig, R.; Vial, J.

    2015-01-01

    Six Single-Column Model (SCM) versions of climate models are evaluated on the basis of their representation of the dependence of the stratocumulus-topped boundary layer regime on the free tropospheric thermodynamic conditions. The study includes two idealized experiments corresponding to the

  5. Cross-scale intercomparison of climate change impacts simulated by regional and global hydrological models in eleven large river basins

    Energy Technology Data Exchange (ETDEWEB)

    Hattermann, F. F.; Krysanova, V.; Gosling, S. N.; Dankers, R.; Daggupati, P.; Donnelly, C.; Flörke, M.; Huang, S.; Motovilov, Y.; Buda, S.; Yang, T.; Müller, C.; Leng, G.; Tang, Q.; Portmann, F. T.; Hagemann, S.; Gerten, D.; Wada, Y.; Masaki, Y.; Alemayehu, T.; Satoh, Y.; Samaniego, L.

    2017-01-04

    Ideally, the results from models operating at different scales should agree in trend direction and magnitude of impacts under climate change. However, this implies that the sensitivity of impact models designed for either scale to climate variability and change is comparable. In this study, we compare hydrological changes simulated by 9 global and 9 regional hydrological models (HM) for 11 large river basins in all continents under reference and scenario conditions. The foci are on model validation runs, sensitivity of annual discharge to climate variability in the reference period, and sensitivity of the long-term average monthly seasonal dynamics to climate change. One major result is that the global models, mostly not calibrated against observations, often show a considerable bias in mean monthly discharge, whereas regional models show a much better reproduction of reference conditions. However, the sensitivity of two HM ensembles to climate variability is in general similar. The simulated climate change impacts in terms of long-term average monthly dynamics evaluated for HM ensemble medians and spreads show that the medians are to a certain extent comparable in some cases with distinct differences in others, and the spreads related to global models are mostly notably larger. Summarizing, this implies that global HMs are useful tools when looking at large-scale impacts of climate change and variability, but whenever impacts for a specific river basin or region are of interest, e.g. for complex water management applications, the regional-scale models validated against observed discharge should be used.

  6. Intercomparison and evaluation of global aerosol microphysical properties among AeroCom models of a range of complexity

    Directory of Open Access Journals (Sweden)

    G. W. Mann

    2014-05-01

    Full Text Available Many of the next generation of global climate models will include aerosol schemes which explicitly simulate the microphysical processes that determine the particle size distribution. These models enable aerosol optical properties and cloud condensation nuclei (CCN concentrations to be determined by fundamental aerosol processes, which should lead to a more physically based simulation of aerosol direct and indirect radiative forcings. This study examines the global variation in particle size distribution simulated by 12 global aerosol microphysics models to quantify model diversity and to identify any common biases against observations. Evaluation against size distribution measurements from a new European network of aerosol supersites shows that the mean model agrees quite well with the observations at many sites on the annual mean, but there are some seasonal biases common to many sites. In particular, at many of these European sites, the accumulation mode number concentration is biased low during winter and Aitken mode concentrations tend to be overestimated in winter and underestimated in summer. At high northern latitudes, the models strongly underpredict Aitken and accumulation particle concentrations compared to the measurements, consistent with previous studies that have highlighted the poor performance of global aerosol models in the Arctic. In the marine boundary layer, the models capture the observed meridional variation in the size distribution, which is dominated by the Aitken mode at high latitudes, with an increasing concentration of accumulation particles with decreasing latitude. Considering vertical profiles, the models reproduce the observed peak in total particle concentrations in the upper troposphere due to new particle formation, although modelled peak concentrations tend to be biased high over Europe. Overall, the multi-model-mean data set simulates the global variation of the particle size distribution with a good degree

  7. Inter-comparison of state-of-the-art MSS and geoid models in the Arctic Ocean

    DEFF Research Database (Denmark)

    Skourup, Henriette; Farrell, Sinead; Hendricks, Stefan

    in errors in the estimated freeboard heights, especially in areas with a sparse lead distribution in consolidated ice conditions. Additionally these errors can impact ocean geostrophic current estimates and remaining biases in the models may impact longer-term, multi-sensor oceanographic time-series of sea......State-of-the-art Arctic Ocean mean sea surface (MSS) and geoid models are used to support sea ice freeboard estimation from satellite altimeters, and for oceanographic studies. However, errors in a given model in the high frequency domain, e.g. due to unresolved gravity features, can result...

  8. Inter-comparison of energy balance and hydrological models for land surface energy flux estimation over a whole river catchment

    DEFF Research Database (Denmark)

    Guzinski, R.; Nieto, H.; Stisen, S.

    2015-01-01

    Evapotranspiration (ET) is the main link between the natural water cycle and the land surface energy budget. Therefore water-balance and energy-balance approaches are two of the main methodologies for modelling this process. The water-balance approach is usually implemented as a complex....... The temporal patterns produced by the remote sensing and hydrological models are quite highly correlated (r ≈ 0.8). This indicates potential benefits to the hydrological modelling community of integrating spatial information derived through remote sensing methodology (contained in the ET maps...

  9. Daily temperature changes and variability in ENSEMBLES regional models predictions: Evaluation and intercomparison for the Ebro Valley (NE Iberia)

    KAUST Repository

    El Kenawy, Ahmed M.; Ló pez-Moreno, Juan Ignacio; McCabe, Matthew; Brunsell, Nathaniel A.; Vicente-Serrano, Sergio M.

    2014-01-01

    We employ a suite of regional climate models (RCMs) to assess future changes in summer (JJA) maximum temperature (Tmax) over the Ebro basin, the largest hydrological division in the Iberian Peninsula. Under the A1B emission scenario, future changes

  10. An intercomparison between the surface heat flux feedback in five coupled models, COADS and the NCEP reanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Frankignoul, C.; Kestenare, E. [Universite Pierre et Marie Curie, Institute Pierre-Simon Laplace, Laboratoire d' Oceanographie Dynamique et de Climatologie, 4 place Jussieu, 75252 Paris Cedex 05 (France); Botzet, M. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Carril, A.F. [Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Drange, H. [Nansen Environmental and Remote Sensing Center, Bergen (Norway); Pardaens, A. [Hadley Centre for Climate Prediction and Research, Met Office (United Kingdom); Terray, L.; Sutton, R. [Department of Meteorology, University of Reading (United Kingdom)

    2004-04-01

    The surface heat flux feedback is estimated in the Atlantic and the extra-tropical Indo-Pacific, using monthly heat flux and sea surface temperature anomaly data from control simulations with five global climate models, and it is compared to estimates derived from COADS and the NCEP reanalysis. In all data sets, the heat flux feedback is negative nearly everywhere and damps the sea surface temperature anomalies. At extra-tropical latitudes, it is strongly dominated by the turbulent fluxes. The radiative feedback can be positive or negative, depending on location and season, but it remains small, except in some models in the tropical Atlantic. The negative heat flux feedback is strong in the mid-latitude storm tracks, exceeding 40 W m{sup -2} K{sup -1} at place, but in the Northern Hemisphere it is substantially underestimated in several models. The negative feedback weakens at high latitudes, although the models do not reproduce the weak positive feedback found in NCEP in the northern North Atlantic. The main differences are found in the tropical Atlantic where the heat flux feedback is weakly negative in some models, as in the observations, and strongly negative in others where it can exceed 30 W m{sup -2} K{sup -1} at large scales, in part because of a strong contribution of the radiative fluxes, in particular during spring. A comparison between models with similar atmospheric or oceanic components suggests that the atmospheric model is primarily responsible for the heat flux feedback differences at extra-tropical latitudes. In the tropical Atlantic, the ocean behavior plays an equal role. The differences in heat flux feedback in the tropical Atlantic are reflected in the sea surface temperature anomaly persistence, which is too small in models where the heat flux damping is large. A good representation of the heat flux feedback is thus required to simulate climate variability realistically. (orig.)

  11. The fourth phase of the radiative transfer model intercomparison (RAMI) exercise: Actual canopy scenarios and conformity testing

    Czech Academy of Sciences Publication Activity Database

    Widlowski, J. L.; Mio, C.; Disney, M.; Adams, J.; Andredakis, I.; Atzberger, C.; Brennan, J.; Busetto, L.; Chelle, M.; Ceccherini, G.; Colombo, R.; Coté, J. F.; Eenmaee, A.; Essery, R.; Gastellu-Etchegorry, J. P.; Gobron, N.; Grau, E.; Haverd, V.; Homolová, Lucie; Huang, H.; Hunt, L.; Kobayashi, H.; Koetz, B.; Kuusk, A.; Kuusk, J.; Lang, M.; Lewis, P. E.; Lovell, J. L.; Malenovský, Zbyněk; Meroni, M.; Morsdorf, F.; Mottus, M.; Ni-Meister, W.; Pinty, B.; Rautiainen, M.; Schlerf, M.; Somers, B.; Stuckens, J.; Verstraete, M. M.; Yang, W.; Zhao, F.; Zenone, T.

    2015-01-01

    Roč. 169, nov (2015), s. 418-437 ISSN 0034-4257 Institutional support: RVO:67179843 Keywords : forest reflectance model * absolute radiometric calibration * remote-sensing data * Conformity testing * Radiative transfer * Model benchmarking * 3D virtual plant canopy * Digital hemispherical photography * Optical remote sensing * Shared risk * Guarded acceptance * gcos * iso -13528 Subject RIV: EH - Ecology, Behaviour Impact factor: 5.881, year: 2015

  12. Presentation of the EURODELTA III intercomparison exercise - evaluation of the chemistry transport models' performance on criteria pollutants and joint analysis with meteorology

    Science.gov (United States)

    Bessagnet, Bertrand; Pirovano, Guido; Mircea, Mihaela; Cuvelier, Cornelius; Aulinger, Armin; Calori, Giuseppe; Ciarelli, Giancarlo; Manders, Astrid; Stern, Rainer; Tsyro, Svetlana; García Vivanco, Marta; Thunis, Philippe; Pay, Maria-Teresa; Colette, Augustin; Couvidat, Florian; Meleux, Frédérik; Rouïl, Laurence; Ung, Anthony; Aksoyoglu, Sebnem; María Baldasano, José; Bieser, Johannes; Briganti, Gino; Cappelletti, Andrea; D'Isidoro, Massimo; Finardi, Sandro; Kranenburg, Richard; Silibello, Camillo; Carnevale, Claudio; Aas, Wenche; Dupont, Jean-Charles; Fagerli, Hilde; Gonzalez, Lucia; Menut, Laurent; Prévôt, André S. H.; Roberts, Pete; White, Les

    2016-10-01

    The EURODELTA III exercise has facilitated a comprehensive intercomparison and evaluation of chemistry transport model performances. Participating models performed calculations for four 1-month periods in different seasons in the years 2006 to 2009, allowing the influence of different meteorological conditions on model performances to be evaluated. The exercise was performed with strict requirements for the input data, with few exceptions. As a consequence, most of differences in the outputs will be attributed to the differences in model formulations of chemical and physical processes. The models were evaluated mainly for background rural stations in Europe. The performance was assessed in terms of bias, root mean square error and correlation with respect to the concentrations of air pollutants (NO2, O3, SO2, PM10 and PM2.5), as well as key meteorological variables. Though most of meteorological parameters were prescribed, some variables like the planetary boundary layer (PBL) height and the vertical diffusion coefficient were derived in the model preprocessors and can partly explain the spread in model results. In general, the daytime PBL height is underestimated by all models. The largest variability of predicted PBL is observed over the ocean and seas. For ozone, this study shows the importance of proper boundary conditions for accurate model calculations and then on the regime of the gas and particle chemistry. The models show similar and quite good performance for nitrogen dioxide, whereas they struggle to accurately reproduce measured sulfur dioxide concentrations (for which the agreement with observations is the poorest). In general, the models provide a close-to-observations map of particulate matter (PM2.5 and PM10) concentrations over Europe rather with correlations in the range 0.4-0.7 and a systematic underestimation reaching -10 µg m-3 for PM10. The highest concentrations are much more underestimated, particularly in wintertime. Further evaluation of

  13. Presentation of the EURODELTA III intercomparison exercise – evaluation of the chemistry transport models' performance on criteria pollutants and joint analysis with meteorology

    Directory of Open Access Journals (Sweden)

    B. Bessagnet

    2016-10-01

    Full Text Available The EURODELTA III exercise has facilitated a comprehensive intercomparison and evaluation of chemistry transport model performances. Participating models performed calculations for four 1-month periods in different seasons in the years 2006 to 2009, allowing the influence of different meteorological conditions on model performances to be evaluated. The exercise was performed with strict requirements for the input data, with few exceptions. As a consequence, most of differences in the outputs will be attributed to the differences in model formulations of chemical and physical processes. The models were evaluated mainly for background rural stations in Europe. The performance was assessed in terms of bias, root mean square error and correlation with respect to the concentrations of air pollutants (NO2, O3, SO2, PM10 and PM2.5, as well as key meteorological variables. Though most of meteorological parameters were prescribed, some variables like the planetary boundary layer (PBL height and the vertical diffusion coefficient were derived in the model preprocessors and can partly explain the spread in model results. In general, the daytime PBL height is underestimated by all models. The largest variability of predicted PBL is observed over the ocean and seas. For ozone, this study shows the importance of proper boundary conditions for accurate model calculations and then on the regime of the gas and particle chemistry. The models show similar and quite good performance for nitrogen dioxide, whereas they struggle to accurately reproduce measured sulfur dioxide concentrations (for which the agreement with observations is the poorest. In general, the models provide a close-to-observations map of particulate matter (PM2.5 and PM10 concentrations over Europe rather with correlations in the range 0.4–0.7 and a systematic underestimation reaching −10 µg m−3 for PM10. The highest concentrations are much more underestimated, particularly in

  14. Composition changes after the "Halloween" solar proton event: the High Energy Particle Precipitation in the Atmosphere (HEPPA model versus MIPAS data intercomparison study

    Directory of Open Access Journals (Sweden)

    B. Funke

    2011-09-01

    additional ion chemistry (HNO3 formation via ion-ion recombination and water cluster ions into the chemical schemes. An overestimation of observed H2O2 enhancements by all models hints at an underestimation of the OH/HO2 ratio in the upper polar stratosphere during the SPE. The analysis of chlorine species perturbations has shown that the encountered differences between models and observations, particularly the underestimation of observed ClONO2 enhancements, are related to a smaller availability of ClO in the polar night region already before the SPE. In general, the intercomparison has demonstrated that differences in the meteorology and/or initial state of the atmosphere in the simulations cause a relevant variability of the model results, even on a short timescale of only a few days.

  15. Intercomparison On Depth Dose Measurement

    International Nuclear Information System (INIS)

    Rohmah, N; Akhadi, M

    1996-01-01

    Intercomparation on personal dose evaluation system has been carried out between CSRSR-NAEA of Indonesia toward Standard Laboratory of JAERI (Japan) and ARL (Australia). The intercomparison was in 10 amm depth dose measurement , Hp (10), from the intercomparison result could be stated that personal depth dose measurement conducted by CSRSR was sufficiently good. Deviation of dose measurement result using personal dosemeter of TLD BG-1 type which were used by CSRSR in the intercomparison and routine photon personal dose monitoring was still in internationally agreed limit. Maximum deviation of reported doses by CSRSR compared to delivered doses for dosemeter irradiation by JAERI was -10.0 percent and by ARL was +29 percent. Maximum deviation permitted in personal dose monitoring is ± 50 percent

  16. Intercomparison of Cement Solid-Solution Models. Issues Affecting the Geochemical Evolution of Repositories for Radioactive Waste

    International Nuclear Information System (INIS)

    Benbow, Steven; Savage, David; Walker, Colin

    2007-05-01

    Many concepts for the geological storage of radioactive waste incorporate cement based materials, which act to provide a chemical barrier, impede groundwater flow or provide structural integrity of the underground structures. Thus, it is important to understand the long-term behaviour of these materials when modelling scenarios for the potential release and migration of radionuclides. In the presence of invasive groundwater, the chemical and physical properties of cement, such as its pH buffering capacity, resistance to flow, and its mechanical properties, are expected to evolve with time. Modelling the degradation of cement is complicated by the fact that the long term pH buffer is controlled by the incongruent dissolution behaviour of calcium-silicate-hydrate (C-S-H) gel. It has been previously shown (SKI Report 2005:64) that it is possible to simulate the long term evolution of both the physical and chemical properties of cement based materials in an invasive groundwater using a fully coupled geochemical transport model. The description of the incongruent dissolution of C-S-H gel was based on a binary solid solution aqueous solution (SSAS) between end-member components portlandite (Ca(OH) 2 ) and a C-S-H gel composition expressed by its component oxides (CaH 2 SiO 4 ). The models considered a range of uncertainties including different groundwater compositions, parameterised couplings between the evolution of porosity with permeability and diffusivity and alternative secondary mineral assemblages. The results of the modelling suggested that alternative evolutions were possible under these different conditions. The focus of this report is to address the uncertainty regarding the choice of model for the C-S-H gel dissolution. We compare two alternative C-S-H SSAS models with the one that was used in the previous report, with an emphasis on a direct comparison of the model predictions. Thus we have chosen one simple simulated experimental model based on those in the

  17. The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP contribution to CMIP6: investigation of sea-level and ocean climate change in response to CO2 forcing

    Directory of Open Access Journals (Sweden)

    J. M. Gregory

    2016-11-01

    Full Text Available The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP aims to investigate the spread in simulations of sea-level and ocean climate change in response to CO2 forcing by atmosphere–ocean general circulation models (AOGCMs. It is particularly motivated by the uncertainties in projections of ocean heat uptake, global-mean sea-level rise due to thermal expansion and the geographical patterns of sea-level change due to ocean density and circulation change. FAFMIP has three tier-1 experiments, in which prescribed surface flux perturbations of momentum, heat and freshwater respectively are applied to the ocean in separate AOGCM simulations. All other conditions are as in the pre-industrial control. The prescribed fields are typical of pattern and magnitude of changes in these fluxes projected by AOGCMs for doubled CO2 concentration. Five groups have tested the experimental design with existing AOGCMs. Their results show diversity in the pattern and magnitude of changes, with some common qualitative features. Heat and water flux perturbation cause the dipole in sea-level change in the North Atlantic, while momentum and heat flux perturbation cause the gradient across the Antarctic Circumpolar Current. The Atlantic meridional overturning circulation (AMOC declines in response to the heat flux perturbation, and there is a strong positive feedback on this effect due to the consequent cooling of sea-surface temperature in the North Atlantic, which enhances the local heat input to the ocean. The momentum and water flux perturbations do not substantially affect the AMOC. Heat is taken up largely as a passive tracer in the Southern Ocean, which is the region of greatest heat input, while the weakening of the AMOC causes redistribution of heat towards lower latitudes. Future analysis of these and other phenomena with the wider range of CMIP6 FAFMIP AOGCMs will benefit from new diagnostics of temperature and salinity tendencies, which will enable

  18. Evaluation of preindustrial to present-day black carbon and its albedo forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP

    Directory of Open Access Journals (Sweden)

    Y. H. Lee

    2013-03-01

    Full Text Available As part of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP, we evaluate the historical black carbon (BC aerosols simulated by 8 ACCMIP models against observations including 12 ice core records, long-term surface mass concentrations, and recent Arctic BC snowpack measurements. We also estimate BC albedo forcing by performing additional simulations using offline models with prescribed meteorology from 1996–2000. We evaluate the vertical profile of BC snow concentrations from these offline simulations using the recent BC snowpack measurements. Despite using the same BC emissions, the global BC burden differs by approximately a factor of 3 among models due to differences in aerosol removal parameterizations and simulated meteorology: 34 Gg to 103 Gg in 1850 and 82 Gg to 315 Gg in 2000. However, the global BC burden from preindustrial to present-day increases by 2.5–3 times with little variation among models, roughly matching the 2.5-fold increase in total BC emissions during the same period. We find a large divergence among models at both Northern Hemisphere (NH and Southern Hemisphere (SH high latitude regions for BC burden and at SH high latitude regions for deposition fluxes. The ACCMIP simulations match the observed BC surface mass concentrations well in Europe and North America except at Ispra. However, the models fail to predict the Arctic BC seasonality due to severe underestimations during winter and spring. The simulated vertically resolved BC snow concentrations are, on average, within a factor of 2–3 of the BC snowpack measurements except for Greenland and the Arctic Ocean. For the ice core evaluation, models tend to adequately capture both the observed temporal trends and the magnitudes at Greenland sites. However, models fail to predict the decreasing trend of BC depositions/ice core concentrations from the 1950s to the 1970s in most Tibetan Plateau ice cores. The distinct temporal trend at the Tibetan

  19. Evaluation of preindustrial to present-day black carbon and its albedo forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    Science.gov (United States)

    Lee, Y. H.; Lamarque, J.-F.; Flanner, M. G.; Jiao, C.; Shindell, D. T.; Bernsten, T.; Bisiaux, M. M.; Cao, J.; Collins, W. J.; Curran, M.; hide

    2013-01-01

    As part of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), we evaluate the historical black carbon (BC) aerosols simulated by 8 ACCMIP models against observations including 12 ice core records, long-term surface mass concentrations, and recent Arctic BC snowpack measurements. We also estimate BC albedo forcing by performing additional simulations using offline models with prescribed meteorology from 1996-2000. We evaluate the vertical profile of BC snow concentrations from these offline simulations using the recent BC snowpack measurements. Despite using the same BC emissions, the global BC burden differs by approximately a factor of 3 among models due to differences in aerosol removal parameterizations and simulated meteorology: 34 Gg to 103 Gg in 1850 and 82 Gg to 315 Gg in 2000. However, the global BC burden from preindustrial to present-day increases by 2.5-3 times with little variation among models, roughly matching the 2.5-fold increase in total BC emissions during the same period.We find a large divergence among models at both Northern Hemisphere (NH) and Southern Hemisphere (SH) high latitude regions for BC burden and at SH high latitude regions for deposition fluxes. The ACCMIP simulations match the observed BC surface mass concentrations well in Europe and North America except at Ispra. However, the models fail to predict the Arctic BC seasonality due to severe underestimations during winter and spring. The simulated vertically resolved BC snow concentrations are, on average, within a factor of 2-3 of the BC snowpack measurements except for Greenland and the Arctic Ocean. For the ice core evaluation, models tend to adequately capture both the observed temporal trends and the magnitudes at Greenland sites. However, models fail to predict the decreasing trend of BC depositions/ice core concentrations from the 1950s to the 1970s in most Tibetan Plateau ice cores. The distinct temporal trend at the Tibetan Plateau ice cores

  20. ARM/GCSS/SPARC TWP-ICE CRM Intercomparison Study

    Science.gov (United States)

    Fridlind, Ann; Ackerman, Andrew; Petch, Jon; Field, Paul; Hill, Adrian; McFarquhar, Greg; Xie, Shaocheng; Zhang, Minghua

    2010-01-01

    Specifications are provided for running a cloud-resolving model (CRM) and submitting results in a standardized format for inclusion in a n intercomparison study and archiving for public access. The simulated case study is based on measurements obtained during the 2006 Tropical Warm Pool - International Cloud Experiment (TWP-ICE) led by the U. S. department of Energy Atmospheric Radiation Measurement (ARM) program. The modeling intercomparison study is based on objectives developed in concert with the Stratospheric Processes And their Role in Climate (SPARC) program and the GEWEX cloud system study (GCSS) program. The Global Energy and Water Cycle Experiment (GEWEX) is a core project of the World Climate Research PRogramme (WCRP).

  1. Assessing the impacts of 1.5 °C global warming – simulation protocol of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2b

    Directory of Open Access Journals (Sweden)

    K. Frieler

    2017-11-01

    Full Text Available In Paris, France, December 2015, the Conference of the Parties (COP to the United Nations Framework Convention on Climate Change (UNFCCC invited the Intergovernmental Panel on Climate Change (IPCC to provide a special report in 2018 on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways. In Nairobi, Kenya, April 2016, the IPCC panel accepted the invitation. Here we describe the response devised within the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP to provide tailored, cross-sectorally consistent impact projections to broaden the scientific basis for the report. The simulation protocol is designed to allow for (1 separation of the impacts of historical warming starting from pre-industrial conditions from impacts of other drivers such as historical land-use changes (based on pre-industrial and historical impact model simulations; (2 quantification of the impacts of additional warming up to 1.5 °C, including a potential overshoot and long-term impacts up to 2299, and comparison to higher levels of global mean temperature change (based on the low-emissions Representative Concentration Pathway RCP2.6 and a no-mitigation pathway RCP6.0 with socio-economic conditions fixed at 2005 levels; and (3 assessment of the climate effects based on the same climate scenarios while accounting for simultaneous changes in socio-economic conditions following the middle-of-the-road Shared Socioeconomic Pathway (SSP2, Fricko et al., 2016 and in particular differential bioenergy requirements associated with the transformation of the energy system to comply with RCP2.6 compared to RCP6.0. With the aim of providing the scientific basis for an aggregation of impacts across sectors and analysis of cross-sectoral interactions that may dampen or amplify sectoral impacts, the protocol is designed to facilitate consistent impact projections from a range of impact models across

  2. Assessing the impacts of 1.5 °C global warming - simulation protocol of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2b)

    Science.gov (United States)

    Frieler, Katja; Lange, Stefan; Piontek, Franziska; Reyer, Christopher P. O.; Schewe, Jacob; Warszawski, Lila; Zhao, Fang; Chini, Louise; Denvil, Sebastien; Emanuel, Kerry; Geiger, Tobias; Halladay, Kate; Hurtt, George; Mengel, Matthias; Murakami, Daisuke; Ostberg, Sebastian; Popp, Alexander; Riva, Riccardo; Stevanovic, Miodrag; Suzuki, Tatsuo; Volkholz, Jan; Burke, Eleanor; Ciais, Philippe; Ebi, Kristie; Eddy, Tyler D.; Elliott, Joshua; Galbraith, Eric; Gosling, Simon N.; Hattermann, Fred; Hickler, Thomas; Hinkel, Jochen; Hof, Christian; Huber, Veronika; Jägermeyr, Jonas; Krysanova, Valentina; Marcé, Rafael; Müller Schmied, Hannes; Mouratiadou, Ioanna; Pierson, Don; Tittensor, Derek P.; Vautard, Robert; van Vliet, Michelle; Biber, Matthias F.; Betts, Richard A.; Bodirsky, Benjamin Leon; Deryng, Delphine; Frolking, Steve; Jones, Chris D.; Lotze, Heike K.; Lotze-Campen, Hermann; Sahajpal, Ritvik; Thonicke, Kirsten; Tian, Hanqin; Yamagata, Yoshiki

    2017-11-01

    In Paris, France, December 2015, the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC) invited the Intergovernmental Panel on Climate Change (IPCC) to provide a special report in 2018 on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways. In Nairobi, Kenya, April 2016, the IPCC panel accepted the invitation. Here we describe the response devised within the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) to provide tailored, cross-sectorally consistent impact projections to broaden the scientific basis for the report. The simulation protocol is designed to allow for (1) separation of the impacts of historical warming starting from pre-industrial conditions from impacts of other drivers such as historical land-use changes (based on pre-industrial and historical impact model simulations); (2) quantification of the impacts of additional warming up to 1.5 °C, including a potential overshoot and long-term impacts up to 2299, and comparison to higher levels of global mean temperature change (based on the low-emissions Representative Concentration Pathway RCP2.6 and a no-mitigation pathway RCP6.0) with socio-economic conditions fixed at 2005 levels; and (3) assessment of the climate effects based on the same climate scenarios while accounting for simultaneous changes in socio-economic conditions following the middle-of-the-road Shared Socioeconomic Pathway (SSP2, Fricko et al., 2016) and in particular differential bioenergy requirements associated with the transformation of the energy system to comply with RCP2.6 compared to RCP6.0. With the aim of providing the scientific basis for an aggregation of impacts across sectors and analysis of cross-sectoral interactions that may dampen or amplify sectoral impacts, the protocol is designed to facilitate consistent impact projections from a range of impact models across different sectors (global

  3. Cloud-Resolving Modeling Intercomparison Study of a Squall Line Case from MC3E - Properties of Convective Core

    Science.gov (United States)

    Fan, J.; Han, B.; Varble, A.; Morrison, H.; North, K.; Kollias, P.; Chen, B.; Dong, X.; Giangrande, S. E.; Khain, A.; Lin, Y.; Mansell, E.; Milbrandt, J.; Stenz, R.; Thompson, G.; Wang, Y.

    2016-12-01

    The large spread in CRM model simulations of deep convection and aerosol effects on deep convective clouds (DCCs) makes it difficult to (1) further our understanding of deep convection and (2) define "benchmarks" and then limit their use in parameterization developments. A constrained model intercomparsion study on a mid-latitude mesoscale squall line is performed using the Weather Research & Forecasting (WRF) model at 1-km horizontal grid spacing with eight cloud microphysics schemes to understand specific processes that lead to the large spreads of simulated convection and precipitation. Various observational data are employed to evaluate the baseline simulations. All simulations tend to produce a wider convective area but a much narrower stratiform area. The magnitudes of virtual potential temperature drop, pressure rise, and wind speed peak associated with the passage of the gust front are significantly smaller compared with the observations, suggesting simulated cool pools are weaker. Simulations generally overestimate the vertical velocity and radar reflectivity in convective cores compared with the retrievals. The modeled updraft velocity and precipitation have a significant spread across eight schemes. The spread of updraft velocity is the combination of both low-level pressure perturbation gradient (PPG) and buoyancy. Both PPG and thermal buoyancy are small for simulations of weak convection but both are large for those of strong convection. Ice-related parameterizations contribute majorly to the spread of updraft velocity, while they are not the reason for the large spread of precipitation. The understandings gained in this study can help to focus future observations and parameterization development.

  4. TransCom N2O model inter-comparison, Part II : Atmospheric inversion estimates of N2O emissions

    NARCIS (Netherlands)

    Thompson, R. L.; Ishijima, K.; Saikawa, E.; Corazza, M.; Karstens, U.; Patra, P. K.; Bergamaschi, P.; Chevallier, F.; Dlugokencky, E.; Prinn, R. G.; Weiss, R. F.; O'Doherty, S.; Fraser, P. J.; Steele, L. P.; Krummel, P. B.; Vermeulen, A.; Tohjima, Y.; Jordan, A.; Haszpra, L.; Steinbacher, M.; Van Der Laan, S.; Aalto, T.; Meinhardt, F.; Popa, Maria Elena; Moncrieff, J.; Bousquet, P.

    2014-01-01

    This study examines N2O emission estimates from 5 different atmospheric inversion frameworks. The 5 frameworks differ in the choice of atmospheric transport model, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation dataset. The mean

  5. TransCom N2O model inter-comparison - Part 2 : Atmospheric inversion estimates of N2O emissions

    NARCIS (Netherlands)

    Thompson, R. L.; Ishijima, K.; Saikawa, E.; Corazza, M.; Karstens, U.; Patra, P. K.; Bergamaschi, P.; Chevallier, F.; Dlugokencky, E.; Prinn, R. G.; Weiss, R. F.; O'Doherty, S.; Fraser, P. J.; Steele, L. P.; Krummel, P. B.; Vermeulen, A.; Tohjima, Y.; Jordan, A.; Haszpra, L.; Steinbacher, M.; Van Der Laan, S.; Aalto, T.; Meinhardt, F.; Popa, Maria Elena|info:eu-repo/dai/nl/375806407; Moncrieff, J.; Bousquet, P.

    2014-01-01

    This study examines N2O emission estimates from five different atmospheric inversion frameworks based on chemistry transport models (CTMs). The five frameworks differ in the choice of CTM, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation

  6. How accurate are estimates of glacier ice thickness? Results from ITMIX, the Ice Thickness Models Intercomparison eXperiment

    DEFF Research Database (Denmark)

    Farinotti, Daniel; Brinkerhoff, Douglas J.; Clarke, Garry K. C.

    2017-01-01

    Knowledge of the ice thickness distribution of glaciers and ice caps is an important prerequisite for many glaciological and hydrological investigations. A wealth of approaches has recently been presented for inferring ice thickness from characteristics of the surface. With the Ice Thickness Models...

  7. Intercomparison and Evaluation of Aerosol Microphysical Properties among AeroCom Global Models of a Range of Complexity

    Czech Academy of Sciences Publication Activity Database

    Mann, G.W.; Carslaw, K.S.; Reddington, C.L.; Pringle, K.J.; Schulz, M.; Asmi, A.; Spracklen, D.V.; Ridley, D.A.; Woodhouse, M.T.; Lee, L.A.; Zhang, K.; Ghan, S.H.; Easter, R.C.; Liu, X.; Stier, P.; Lee, Y.H.; Adams, P.J.; Tost, H.; Lelieveld, J.; Bauer, S.E.; Tsigaridis, K.; van Noije, T.P.C.; Strunk, A.; Vignati, E.; Bellouin, N.; Dalvi, M.; Johnson, C.E.; Bergman, T.; Kokkola, H.; von Salzen, K.; Yu, F.; Luo, G.; Petzold, A.; Heintzenberger, J.; Clarke, A.; Ogren, J.A.; Gras, J.; Baltensperger, U.; Kaminski, U.; Jennings, S.G.; O'Dowd, C.D.; Harrison, R. M.; Beddows, D.C.S.; Kulmala, M.; Viisanen, Y.; Ulevicius, V.; Mihalopoulos, N.; Ždímal, Vladimír; Fiebich, M.; Hansson, H.-C.; Swietlicki, E.; Henzig, J.S.

    2014-01-01

    Roč. 14, č. 9 (2014), s. 4679-4713 ISSN 1680-7316 Institutional support: RVO:67985858 Keywords : global climate models * aerosol processes * particle size distributions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.053, year: 2014

  8. The "Grey Zone" cold air outbreak global model intercomparison: A cross evaluation using large-eddy simulations

    Science.gov (United States)

    Tomassini, Lorenzo; Field, Paul R.; Honnert, Rachel; Malardel, Sylvie; McTaggart-Cowan, Ron; Saitou, Kei; Noda, Akira T.; Seifert, Axel

    2017-03-01

    A stratocumulus-to-cumulus transition as observed in a cold air outbreak over the North Atlantic Ocean is compared in global climate and numerical weather prediction models and a large-eddy simulation model as part of the Working Group on Numerical Experimentation "Grey Zone" project. The focus of the project is to investigate to what degree current convection and boundary layer parameterizations behave in a scale-adaptive manner in situations where the model resolution approaches the scale of convection. Global model simulations were performed at a wide range of resolutions, with convective parameterizations turned on and off. The models successfully simulate the transition between the observed boundary layer structures, from a well-mixed stratocumulus to a deeper, partly decoupled cumulus boundary layer. There are indications that surface fluxes are generally underestimated. The amount of both cloud liquid water and cloud ice, and likely precipitation, are under-predicted, suggesting deficiencies in the strength of vertical mixing in shear-dominated boundary layers. But also regulation by precipitation and mixed-phase cloud microphysical processes play an important role in the case. With convection parameterizations switched on, the profiles of atmospheric liquid water and cloud ice are essentially resolution-insensitive. This, however, does not imply that convection parameterizations are scale-aware. Even at the highest resolutions considered here, simulations with convective parameterizations do not converge toward the results of convection-off experiments. Convection and boundary layer parameterizations strongly interact, suggesting the need for a unified treatment of convective and turbulent mixing when addressing scale-adaptivity.

  9. Intercomparison of Streamflow Simulations between WRF-Hydro and Hydrology Laboratory-Research Distributed Hydrologic Model Frameworks

    Science.gov (United States)

    KIM, J.; Smith, M. B.; Koren, V.; Salas, F.; Cui, Z.; Johnson, D.

    2017-12-01

    The National Oceanic and Atmospheric Administration (NOAA)-National Weather Service (NWS) developed the Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) framework as an initial step towards spatially distributed modeling at River Forecast Centers (RFCs). Recently, the NOAA/NWS worked with the National Center for Atmospheric Research (NCAR) to implement the National Water Model (NWM) for nationally-consistent water resources prediction. The NWM is based on the WRF-Hydro framework and is run at a 1km spatial resolution and 1-hour time step over the contiguous United States (CONUS) and contributing areas in Canada and Mexico. In this study, we compare streamflow simulations from HL-RDHM and WRF-Hydro to observations from 279 USGS stations. For streamflow simulations, HL-RDHM is run on 4km grids with the temporal resolution of 1 hour for a 5-year period (Water Years 2008-2012), using a priori parameters provided by NOAA-NWS. The WRF-Hydro streamflow simulations for the same time period are extracted from NCAR's 23 retrospective run of the NWM (version 1.0) over CONUS based on 1km grids. We choose 279 USGS stations which are relatively less affected by dams or reservoirs, in the domains of six different RFCs. We use the daily average values of simulations and observations for the convenience of comparison. The main purpose of this research is to evaluate how HL-RDHM and WRF-Hydro perform at USGS gauge stations. We compare daily time-series of observations and both simulations, and calculate the error values using a variety of error functions. Using these plots and error values, we evaluate the performances of HL-RDHM and WRF-Hydro models. Our results show a mix of model performance across geographic regions.

  10. Intercomparison of modal and sectional aerosol microphysics representations within the same 3-D global chemical transport model

    Directory of Open Access Journals (Sweden)

    G. W. Mann

    2012-05-01

    Full Text Available In the most advanced aerosol-climate models it is common to represent the aerosol particle size distribution in terms of several log-normal modes. This approach, motivated by computational efficiency, makes assumptions about the shape of the particle distribution that may not always capture the properties of global aerosol. Here, a global modal aerosol microphysics module (GLOMAP-mode is evaluated and improved by comparing against a sectional version (GLOMAP-bin and observations in the same 3-D global offline chemistry transport model. With both schemes, the model captures the main features of the global particle size distribution, with sub-micron aerosol approximately unimodal in continental regions and bi-modal in marine regions. Initial bin-mode comparisons showed that the current values for two size distribution parameter settings in the modal scheme (mode widths and inter-modal separation sizes resulted in clear biases compared to the sectional scheme. By adjusting these parameters in the modal scheme, much better agreement is achieved against the bin scheme and observations. Annual mean surface-level mass of sulphate, sea-salt, black carbon (BC and organic carbon (OC are within 25% in the two schemes in nearly all regions. Surface level concentrations of condensation nuclei (CN, cloud condensation nuclei (CCN, surface area density and condensation sink also compare within 25% in most regions. However, marine CCN concentrations between 30° N and 30° S are systematically 25–60% higher in the modal model, which we attribute to differences in size-resolved particle growth or cloud-processing. Larger differences also exist in regions or seasons dominated by biomass burning and in free-troposphere and high-latitude regions. Indeed, in the free-troposphere, GLOMAP-mode BC is a factor 2–4 higher than GLOMAP-bin, likely due to differences in size-resolved scavenging. Nevertheless, in most parts of the atmosphere, we conclude that bin

  11. Air quality modelling in the summer over the eastern Mediterranean using WRF-Chem: chemistry and aerosol mechanism intercomparison

    Science.gov (United States)

    Georgiou, George K.; Christoudias, Theodoros; Proestos, Yiannis; Kushta, Jonilda; Hadjinicolaou, Panos; Lelieveld, Jos

    2018-02-01

    We employ the WRF-Chem model to study summertime air pollution, the intense photochemical activity and their impact on air quality over the eastern Mediterranean. We utilize three nested domains with horizontal resolutions of 80, 16 and 4 km, with the finest grid focusing on the island of Cyprus, where the CYPHEX campaign took place in July 2014. Anthropogenic emissions are based on the EDGAR HTAP global emission inventory, while dust and biogenic emissions are calculated online. Three simulations utilizing the CBMZ-MOSAIC, MOZART-MOSAIC, and RADM2-MADE/SORGAM gas-phase and aerosol mechanisms are performed. The results are compared with measurements from a dense observational network of 14 ground stations in Cyprus. The model simulates T2 m, Psurf, and WD10 m accurately, with minor differences in WS10 m between model and observations at coastal and mountainous stations attributed to limitations in the representation of the complex topography in the model. It is shown that the south-eastern part of Cyprus is mostly affected by emissions from within the island, under the dominant (60 %) westerly flow during summertime. Clean maritime air from the Mediterranean can reduce concentrations of local air pollutants over the region during westerlies. Ozone concentrations are overestimated by all three mechanisms (9 % ≤ NMB ≤ 23 %) with the smaller mean bias (4.25 ppbV) obtained by the RADM2-MADE/SORGAM mechanism. Differences in ozone concentrations can be attributed to the VOC treatment by the three mechanisms. The diurnal variability of pollution and ozone precursors is not captured (hourly correlation coefficients for O3 ≤ 0.29). This might be attributed to the underestimation of NOx concentrations by local emissions by up to 50 %. For the fine particulate matter (PM2.5), the lowest mean bias (9 µg m-3) is obtained with the RADM2-MADE/SORGAM mechanism, with overestimates in sulfate and ammonium aerosols. Overestimation of sulfate aerosols by this mechanism may be

  12. An intercomparison of stratospheric gravity wave potential energy densities from METOP GPS radio occultation measurements and ECMWF model data

    Science.gov (United States)

    Rapp, Markus; Dörnbrack, Andreas; Kaifler, Bernd

    2018-02-01

    Temperature profiles based on radio occultation (RO) measurements with the operational European METOP satellites are used to derive monthly mean global distributions of stratospheric (20-40 km) gravity wave (GW) potential energy densities (EP) for the period July 2014-December 2016. In order to test whether the sampling and data quality of this data set is sufficient for scientific analysis, we investigate to what degree the METOP observations agree quantitatively with ECMWF operational analysis (IFS data) and reanalysis (ERA-Interim) data. A systematic comparison between corresponding monthly mean temperature fields determined for a latitude-longitude-altitude grid of 5° by 10° by 1 km is carried out. This yields very low systematic differences between RO and model data below 30 km (i.e., median temperature differences is between -0.2 and +0.3 K), which increases with height to yield median differences of +1.0 K at 34 km and +2.2 K at 40 km. Comparing EP values for three selected locations at which also ground-based lidar measurements are available yields excellent agreement between RO and IFS data below 35 km. ERA-Interim underestimates EP under conditions of strong local mountain wave forcing over northern Scandinavia which is apparently not resolved by the model. Above 35 km, RO values are consistently much larger than model values, which is likely caused by the model sponge layer, which damps small-scale fluctuations above ˜ 32 km altitude. Another reason is the well-known significant increase of noise in RO measurements above 35 km. The comparison between RO and lidar data reveals very good qualitative agreement in terms of the seasonal variation of EP, but RO values are consistently smaller than lidar values by about a factor of 2. This discrepancy is likely caused by the very different sampling characteristics of RO and lidar observations. Direct comparison of the global data set of RO and model EP fields shows large correlation coefficients (0

  13. Corrosion studies of tantalum in oxidizing media - intercomparison of data obtained in model media and in a test facility

    International Nuclear Information System (INIS)

    Vehlow, J.; Wieczorek, H.

    1989-01-01

    The suitability of tantalum as a material for wet incineration of combustible wastes has been tested in model mixtures of sulfuric and nitric acid at about 250deg C. In addition parts of a semi-technical test facility have been investigated, which had been in operation for more than 3000 h. In general there is good correspondence between predicted wall losses and those found under real conditions. (orig.) [de

  14. Daily temperature changes and variability in ENSEMBLES regional models predictions: Evaluation and intercomparison for the Ebro Valley (NE Iberia)

    KAUST Repository

    El Kenawy, Ahmed M.

    2014-12-18

    We employ a suite of regional climate models (RCMs) to assess future changes in summer (JJA) maximum temperature (Tmax) over the Ebro basin, the largest hydrological division in the Iberian Peninsula. Under the A1B emission scenario, future changes in both mean values and their corresponding time varying percentiles were examined by comparing the control period (1971-2000) with two future time slices: 2021-2050 and 2071-2100. Here, the rationale is to assess how lower/upper tails of temperature distributions will change in the future and whether these changes will be consistent with those of the mean. The model validation results demonstrate significant differences among the models in terms of their capability to representing the statistical characteristics (e.g., mean, skewness and asymmetry) of the observed climate. The results also indicate that the current substantial warming observed in the Ebro basin is expected to continue during the 21st century, with more intense warming occurring at higher altitudes and in areas with greater distance from coastlines. All models suggest that the region will experience significant positive changes in both the cold and warm tails of temperature distributions. However, the results emphasize that future changes in the lower and upper tails of the summer Tmax distribution may not follow the same warming rate as the mean condition. In particular, the projected changes in the warm tail of the summer Tmax are shown to be significantly larger than changes in both mean values and the cold tail, especially at the end of the 21st century. The finding suggests that much of the changes in the summer Tmax percentiles will be driven by a shift in the entire distribution of temperature rather than only changes in the central tendency. Better understanding of the possible implications of future climate systems provides information useful for vulnerability assessments and the development of local adaptation strategies for multi

  15. Application of WRF/Chem over East Asia: Part I. Model evaluation and intercomparison with MM5/CMAQ

    Science.gov (United States)

    Zhang, Yang; Zhang, Xin; Wang, Litao; Zhang, Qiang; Duan, Fengkui; He, Kebin

    2016-01-01

    In this work, the application of the online-coupled Weather Research and Forecasting model with chemistry (WRF/Chem) version 3.3.1 is evaluated over East Asia for January, April, July, and October 2005 and compared with results from a previous application of an offline model system, i.e., the Mesoscale Model and Community Multiple Air Quality modeling system (MM5/CMAQ). The evaluation of WRF/Chem is performed using multiple observational datasets from satellites and surface networks in mainland China, Hong Kong, Taiwan, and Japan. WRF/Chem simulates well specific humidity (Q2) and downward longwave and shortwave radiation (GLW and GSW) with normalized mean biases (NMBs) within 24%, but shows moderate to large biases for temperature at 2-m (T2) (NMBs of -9.8% to 75.6%) and precipitation (NMBs of 11.4-92.7%) for some months, and wind speed at 10-m (WS10) (NMBs of 66.5-101%), for all months, indicating some limitations in the YSU planetary boundary layer scheme, the Purdue Lin cloud microphysics, and the Grell-Devenyi ensemble scheme. WRF/Chem can simulate the column abundances of gases reasonably well with NMBs within 30% for most months but moderately to significantly underpredicts the surface concentrations of major species at all sites in nearly all months with NMBs of -72% to -53.8% for CO, -99.4% to -61.7% for NOx, -84.2% to -44.5% for SO2, -63.9% to -25.2% for PM2.5, and -68.9% to 33.3% for PM10, and aerosol optical depth in all months except for October with NMBs of -38.7% to -16.2%. The model significantly overpredicts surface concentrations of O3 at most sites in nearly all months with NMBs of up to 160.3% and NO3- at the Tsinghua site in all months. Possible reasons for large underpredictions include underestimations in the anthropogenic emissions of CO, SO2, and primary aerosol, inappropriate vertical distributions of emissions of SO2 and NO2, uncertainties in upper boundary conditions (e.g., for O3 and CO), missing or inaccurate model representations (e

  16. Atmospheric stability and turbulence fluxes at Horns Rev—an intercomparison of sonic, bulk and WRF model data

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Hahmann, Andrea N.

    2012-01-01

    anemometer at 15 m height and potential temperature differences between the water and the air above. Surface flux estimations from the advanced weather research and forecast (WRF) model are also validated against the sonic and bulk data. The correlation between the sonic and bulk estimates of friction...... to the surface, not only from a systematic bulk and WRF under‐prediction of the friction velocity when compared with the sonic value but also because of the lower magnitude of the sonic heat flux compared with that from the WRF simulations. Although they are not measured but parameterized or estimated, the bulk......–WRF comparisons of friction velocity and 10 m wind speed show good agreement. It is also shown that on a long‐term basis, the WRF and bulk estimates of stability are nearly equal and that a correction towards a slightly stable atmospheric condition has to be applied to the long‐term wind profile at Horns Rev...

  17. Evaluation of Cloud-Resolving and Limited Area Model Intercomparison Simulations Using TWP-ICE Observations. Part 2 ; Precipitation Microphysics

    Science.gov (United States)

    Varble, Adam; Zipser, Edward J.; Fridland, Ann M.; Zhu, Ping; Ackerman, Andrew S.; Chaboureau, Jean-Pierre; Fan, Jiwen; Hill, Adrian; Shipway, Ben; Williams, Christopher

    2014-01-01

    Ten 3-D cloud-resolving model (CRM) simulations and four 3-D limited area model (LAM) simulations of an intense mesoscale convective system observed on 23-24 January 2006 during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE) are compared with each other and with observations and retrievals from a scanning polarimetric radar, colocated UHF and VHF vertical profilers, and a Joss-Waldvogel disdrometer in an attempt to explain a low bias in simulated stratiform rainfall. Despite different forcing methodologies, similar precipitation microphysics errors appear in CRMs and LAMs with differences that depend on the details of the bulk microphysics scheme used. One-moment schemes produce too many small raindrops, which biases Doppler velocities low, but produces rainwater contents (RWCs) that are similar to observed. Two-moment rain schemes with a gamma shape parameter (mu) of 0 produce excessive size sorting, which leads to larger Doppler velocities than those produced in one-moment schemes but lower RWCs. Two-moment schemes also produce a convective median volume diameter distribution that is too broad relative to observations and, thus, may have issues balancing raindrop formation, collision-coalescence, and raindrop breakup. Assuming a mu of 2.5 rather than 0 for the raindrop size distribution improves one-moment scheme biases, and allowing mu to have values greater than 0 may improve excessive size sorting in two-moment schemes. Underpredicted stratiform rain rates are associated with underpredicted ice water contents at the melting level rather than excessive rain evaporation, in turn likely associated with convective detrainment that is too high in the troposphere and mesoscale circulations that are too weak. A limited domain size also prevents a large, well-developed stratiform region like the one observed from developing in CRMs, although LAMs also fail to produce such a region.

  18. Intercomparison of transuranics in sediments

    International Nuclear Information System (INIS)

    Nilsson, K.

    1981-01-01

    This paper summarizes the results of a recent intercomparison of transuranic analyses in Nordic sediments undertaken by five laboratories. Five different samplers were tested to determine their consistency and utility. Plutonium and americium were determined in all the samples and the analysis of variance is discussed. (author)

  19. Assimilation of passive and active CCI soil moisture products into hydrological modelling: an intercomparison study in Europe

    Science.gov (United States)

    Maggioni, V.; Massari, C.; Camici, S.; Brocca, L.; Marchesini, I.

    2017-12-01

    Soil moisture (SM) is a key variable in rainfall-runoff partitioning since it acts on the main hydrological processes taking part within a catchment. Modeling SM is often a difficult task due to its large variability at different temporal and spatial scales. Ground soil moisture measurements are a valuable tool for improving runoff prediction but are often limited and suffer from spatial representativeness issues. Remotely sensed observations offer a new source of data able to cope the latter issues thus opening new possibilities for improving flood simulations worldwide. Today, several different SM products are available at increased accuracy with respect to the past. Some interesting products are those derived from the Climate Change Initiative (CCI) which offer the most complete and most consistent global SM data record based on active and passive microwave sensors.Thanks to the combination of multiple sensors within an active, a passive and an active+passive products, the CCI SM is expected to provide a significant benefit for the improvement of rainfall-runoff simulations through data assimilation. However, previous studies have shown that the success of the assimilation is not only related to the accuracy of the observations but also to the specific climate and the catchment physical and hydrological characteristics as well as to many necessary choices related to the assimilation technique. These choices along with the type of SM observations (i.e. passive or active) might play an important role for the success or the failure of the assimilation exercise which is not still clear. In this study, based on a large dataset of catchments covering large part of the Europe, we assimilated satellite SM observations from the passive and the active CCI SM products into Modello Idrologico Semiditribuito in Continuo (MISDc, Brocca et al. 2011). Rainfall and temperature data were collected from the European Climate Assessment & Dataset (E-OBS) while discharge data were

  20. Preliminary report: STOIC CGCM intercomparison - equatorial sections

    International Nuclear Information System (INIS)

    Davey, M; Huddleston, M; Sperber, K R.

    1999-01-01

    An intercomparison and assessment of the tropical behaviour of coupled general circulation models (CGCMs) is being carried out, to identify common strengths and weaknesses and thus guide future CGCM development. The work is being carried out as part of the CLIVAR climate research programme, as a WG-SIP (Working Group on Seasonal to Interannual Prediction) project called STOIC (Study of Tropical Oceans In CGCMs), organised by Michael Davey. This project complements a companion sub-project called ENSIP (El Ni no Simulation Intercomparison Project) organised by Mojib Latif (Max- Planck-Institute for Meteorology) that focusses on equatorial Pacific CGCM behaviour (Latif et al. 1999). Previous coupled model assessments (Mechoso et al. 1995, Neelin et al. 1992, and ENSIP) have focussed on tropical Pacific behaviour. The aim of STOIC is to look at model performance in all tropical ocean regions. This status report contains a sample of the STOIC assessment work, highlighting mean and inter- annual equatorial sea surface temperatures and zonal windstresses. The intention is to submit STOIC and ENSIP papers in mid-1999 for publication together in a refereed journal

  1. UK laboratory intercomparison on internal dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Speed, J.; Birchall, A.; Bull, R.; Cockerill, R.; Jarvis, N.S.; Marsh, J.W.; Peace, M.S.; Roberts, G.; Scarlett, C.; Spencer, D.; Stewart, P

    2003-07-01

    A laboratory intercomparison for internal dose assessment from a variety of intake scenarios is described. This is the first UK intercomparison using the revised ICRP Human Respiratory Tract and biokinetic models. Four United Kingdom laboratories participated and six cases were assessed. Overall, the agreement in internal dose assessments between laboratories was considered satisfactory with 79% of the assessed committed effective doses, e(50), for cases within a band of {+-}40% of the median value. The range (highest/lowest) in e(50) estimated by the laboratories was smallest (1.2) for a case involving inhalation of {sup 137}Cs. The range was greatest (6.0) for a case involving a wound with, and possible inhalation of, {sup 238}Pu, {sup 239}Pu and {sup 241}Am; the variation between laboratories in assessment of intakes could not be considered to be satisfactory in this case. Judgements on the most appropriate data to use in estimating intakes, choice of parameter values for use with the ICRP models and allowing for the effects of treatment with DTPA were important sources of variability between laboratories. (author)

  2. Intercomparison of active personal dosemeters in interventional radiology

    International Nuclear Information System (INIS)

    Clairand, I.; Struelens, L.; Bordy, J. M.; Daures, J.; Debroas, J.; Denozieres, M.; Donadille, L.; Gouriou, J.; Itie, C.; Vaz, P.; D'Errico, F.

    2008-01-01

    The use of active personal dosemeters (APD) in interventional radiology was evaluated by Working Group 9 (Radiation protection dosimetry of medical staff) of the CONRAD project, which is a Coordination Action supported by the European Commission within its sixth Framework Programme. Interventional radiology procedures can be very complex and they can lead to relatively high doses to personnel who stand close to the primary radiation field and are mostly exposed to radiation scattered by the patient. For the adequate dosimetry of the scattered photons, APDs must be able to respond to low-energy [10-100 keV] and pulsed radiation with relatively high instantaneous dose rates. An intercomparison of five APD models deemed suitable for application in interventional radiology was organised in March 2007. The intercomparison used pulsed and continuous radiation beams, at CEA-LIST (Saclay (France)) and IRSN (Fontenay-aux-Roses (France)), respectively. A specific configuration, close to the clinical practice, was considered. The reference dose, in terms of Hp(10), was derived from air kerma measurements and from the measured and calculated energy distributions of the scattered radiation field. Additional Monte Carlo calculations were performed to investigate the energy spectra for different experimental conditions of the intercomparison. The results of this intercomparison are presented in this work and indicate which APDs are able to provide a correct response when used in the specific low-energy spectra and dose rates of pulsed X-rays encountered in interventional radiology. (authors)

  3. Pinatubo Emulation in Multiple Models (POEMs): co-ordinated experiments in the ISA-MIP model intercomparison activity component of the SPARC Stratospheric Sulphur and it's Role in Climate initiative (SSiRC)

    Science.gov (United States)

    Lee, Lindsay; Mann, Graham; Carslaw, Ken; Toohey, Matthew; Aquila, Valentina

    2016-04-01

    The World Climate Research Program's SPARC initiative has a new international activity "Stratospheric Sulphur and its Role in Climate" (SSiRC) to better understand changes in stratospheric aerosol and precursor gaseous sulphur species. One component of SSiRC involves an intercomparison "ISA-MIP" of composition-climate models that simulate the stratospheric aerosol layer interactively. Within PoEMS each modelling group will run a "perturbed physics ensemble" (PPE) of interactive stratospheric aerosol (ISA) simulations of the Pinatubo eruption, varying several uncertain parameters associated with the eruption's SO2 emissions and model processes. A powerful new technique to quantify and attribute sources of uncertainty in complex global models is described by Lee et al. (2011, ACP). The analysis uses Gaussian emulation to derive a probability density function (pdf) of predicted quantities, essentially interpolating the PPE results in multi-dimensional parameter space. Once trained on the ensemble, a Monte Carlo simulation with the fast Gaussian emulator enabling a full variance-based sensitivity analysis. The approach has already been used effectively by Carslaw et al., (2013, Nature) to quantify the uncertainty in the cloud albedo effect forcing from a 3D global aerosol-microphysics model allowing to compare the sensitivy of different predicted quantities to uncertainties in natural and anthropogenic emissions types, and structural parameters in the models. Within ISA-MIP, each group will carry out a PPE of runs, with the subsequent analysis with the emulator assessing the uncertainty in the volcanic forcings predicted by each model. In this poster presentation we will give an outline of the "PoEMS" analysis, describing the uncertain parameters to be varied and the relevance to further understanding differences identified in previous international stratospheric aerosol assessments.

  4. Intercomparison of gamma ray analysis software packages

    International Nuclear Information System (INIS)

    1998-04-01

    The IAEA undertook an intercomparison exercise to review available software for gamma ray spectra analysis. This document describes the methods used in the intercomparison exercise, characterizes the software packages reviewed and presents the results obtained. Only direct results are given without any recommendation for a particular software or method for gamma ray spectra analysis

  5. Air quality and climate change, Topic 3 of the Model Inter-Comparison Study for Asia Phase III (MICS-Asia III – Part 1: Overview and model evaluation

    Directory of Open Access Journals (Sweden)

    M. Gao

    2018-04-01

    Full Text Available Topic 3 of the Model Inter-Comparison Study for Asia (MICS-Asia Phase III examines how online coupled air quality models perform in simulating high aerosol pollution in the North China Plain region during wintertime haze events and evaluates the importance of aerosol radiative and microphysical feedbacks. A comprehensive overview of the MICS-Asia III Topic 3 study design, including descriptions of participating models and model inputs, the experimental designs, and results of model evaluation, are presented. Six modeling groups from China, Korea and the United States submitted results from seven applications of online coupled chemistry–meteorology models. Results are compared to meteorology and air quality measurements, including data from the Campaign on Atmospheric Aerosol Research Network of China (CARE-China and the Acid Deposition Monitoring Network in East Asia (EANET. The correlation coefficients between the multi-model ensemble mean and the CARE-China observed near-surface air pollutants range from 0.51 to 0.94 (0.51 for ozone and 0.94 for PM2.5 for January 2010. However, large discrepancies exist between simulated aerosol chemical compositions from different models. The coefficient of variation (SD divided by the mean can reach above 1.3 for sulfate in Beijing and above 1.6 for nitrate and organic aerosols in coastal regions, indicating that these compositions are less consistent from different models. During clean periods, simulated aerosol optical depths (AODs from different models are similar, but peak values differ during severe haze events, which can be explained by the differences in simulated inorganic aerosol concentrations and the hygroscopic growth efficiency (affected by varied relative humidity. These differences in composition and AOD suggest that future models can be improved by including new heterogeneous or aqueous pathways for sulfate and nitrate formation under hazy conditions, a secondary organic aerosol (SOA

  6. Intercomparison Measurements Zavazna Poruba '98

    International Nuclear Information System (INIS)

    Kostial, J.; Nemcovic, V.; Cabanekova, H.; Durcik, M.; Svatosova, O.; Fueloep, M.; Buban, P.; Galbavy, V.; Dzubara, M.; Svatos, J.

    1998-01-01

    The periodical intercomparison exercises of mobile radiological laboratories was organized in order to improve the measuring methods and to gain a good basis for quality assurance. 20 teams from 10 countries were registered for the workshop from which 20 arrived and participated only as observers. There altogether 73 participants. The list of participants is enclosed in and of this report. The aims of 1998 intercomparison measurements were: (1) to compare the results of the measurements by in-situ spectrometry assuming the different distribution; (2) to improve cooperation among different institutions in Europe; (3) to test the ability of the teams to produce results at the spot; (4) to test the teams capability to produce results for Cs-137 with real distribution without having soil density and alpha/ro prior measurement. The program of the workshop consisted from two parts: field exercises and presentations. Field exercises were: (1) In-situ gamma spectrometry of natural and artificial radionuclides and their contribution to ambient dose rate over an area with heterogeneous distribution of the contamination of cesium-137 at Zavazna Poruba. (2) Dose rate measurement from cobalt-60 source; (3) Identification and determination of activity and depth of a buried source by in-situ spectrometry; (4) Search for lost sources by mobile radiological laboratory; (6) In-situ measurements and dose rate measurement above the water-level of Liptovska Mara; (6) In-situ gamma spectrometry on the bank of the dam an area Liptovsky Trnovec

  7. Chemical Modeling of the Reactivity of Short-Lived Greenhouse Gases: A Model Inter-Comparison Prescribing a Well-Measured, Remote Troposphere

    Science.gov (United States)

    Prather, Michael J.; Flynn, Clare M.; Zhu, Xin; Steenrod, Stephen D.; Strode, Sarah A.; Fiore, Arlene M.; Correa, Gustavo; Murray, Lee T.; Lamarque, Jean-Francois

    2018-01-01

    We develop a new protocol for merging in situ measurements with 3-D model simulations of atmospheric chemistry with the goal of integrating over the data to identify the most reactive air parcels in terms of tropospheric production and loss of the greenhouse gases ozone and methane. Presupposing that we can accurately measure atmospheric composition, we examine whether models constrained by such measurements agree on the chemical budgets for ozone and methane. In applying our technique to a synthetic data stream of 14,880 parcels along 180W, we are able to isolate the performance of the photochemical modules operating within their global chemistry-climate and chemistry-transport models, removing the effects of modules controlling tracer transport, emissions, and scavenging. Differences in reactivity across models are driven only by the chemical mechanism and the diurnal cycle of photolysis rates, which are driven in turn by temperature, water vapor, solar zenith angle, clouds, and possibly aerosols and overhead ozone, which are calculated in each model. We evaluate six global models and identify their differences and similarities in simulating the chemistry through a range of innovative diagnostics. All models agree that the more highly reactive parcels dominate the chemistry (e.g., the hottest 10% of parcels control 25-30% of the total reactivities), but do not fully agree on which parcels comprise the top 10%. Distinct differences in specific features occur, including the regions of maximum ozone production and methane loss, as well as in the relationship between photolysis and these reactivities. Unique, possibly aberrant, features are identified for each model, providing a benchmark for photochemical module development. Among the 6 models tested here, 3 are almost indistinguishable based on the inherent variability caused by clouds, and thus we identify 4, effectively distinct, chemical models. Based on this work, we suggest that water vapor differences in

  8. Third IAEA nuclear accident intercomparison experiment

    Energy Technology Data Exchange (ETDEWEB)

    Miric, I; Ubovic, Z

    1974-05-15

    The purpose of this report is to present the results of the International Atomic Energy Agency intercomparison experiments held at the 'Boris Kidric' Institute, Vinca, in May 1973. The experiments are parts of a multilaboratory intercomparison programme sponsored by the IAEA for the evaluation of nuclear accident dosimetry systems and eventually recommendation of dosimetry systems that will provide adequate informations in the event of a criticality accident. The previous two studies were held at the Valduc Centre near Dijon (France) in June 1970 and at the ORNL in Oak Ridge (USA), in May 1971. Parts of the intercomparison studies were coordination meetings. The topics and conclusions of the Third coordination meeting are given in the Chairman's Report of F.F. Haywood. This paper will deal, therefore, only with data concerning the Third intercomparison experiments in which the RB reactor at Vinca was used as a source of mixed radiation. (author)

  9. Report on the Intercomparison Exercises 1993

    DEFF Research Database (Denmark)

    Aminot, A.; Boer, J. de; Cofino, W.

    This report covers the intercomparison exercises - 1993 of the project Quasimeme - Quality Assurance of Information for Marine Environmental Monitoring in Europe. The report is prepared under contract for the measurement and testing programme (BCR) of the European Community....

  10. Third IAEA nuclear accident intercomparison experiment

    International Nuclear Information System (INIS)

    Miric, I.; Ubovic, Z.

    1974-05-01

    The purpose of this report is to present the results of the International Atomic Energy Agency intercomparison experiments held at the 'Boris Kidric' Institute, Vinca, in May 1973. The experiments are parts of a multilaboratory intercomparison programme sponsored by the IAEA for the evaluation of nuclear accident dosimetry systems and eventually recommendation of dosimetry systems that will provide adequate informations in the event of a criticality accident. The previous two studies were held at the Valduc Centre near Dijon (France) in June 1970 and at the ORNL in Oak Ridge (USA), in May 1971. Parts of the intercomparison studies were coordination meetings. The topics and conclusions of the Third coordination meeting are given in the Chairman's Report of F.F. Haywood. This paper will deal, therefore, only with data concerning the Third intercomparison experiments in which the RB reactor at Vinca was used as a source of mixed radiation. (author)

  11. A multi-model intercomparison of halogenated very short-lived substances (TransCom-VSLS: linking oceanic emissions and tropospheric transport for a reconciled estimate of the stratospheric source gas injection of bromine

    Directory of Open Access Journals (Sweden)

    R. Hossaini

    2016-07-01

    Full Text Available The first concerted multi-model intercomparison of halogenated very short-lived substances (VSLS has been performed, within the framework of the ongoing Atmospheric Tracer Transport Model Intercomparison Project (TransCom. Eleven global models or model variants participated (nine chemical transport models and two chemistry–climate models by simulating the major natural bromine VSLS, bromoform (CHBr3 and dibromomethane (CH2Br2, over a 20-year period (1993–2012. Except for three model simulations, all others were driven offline by (or nudged to reanalysed meteorology. The overarching goal of TransCom-VSLS was to provide a reconciled model estimate of the stratospheric source gas injection (SGI of bromine from these gases, to constrain the current measurement-derived range, and to investigate inter-model differences due to emissions and transport processes. Models ran with standardised idealised chemistry, to isolate differences due to transport, and we investigated the sensitivity of results to a range of VSLS emission inventories. Models were tested in their ability to reproduce the observed seasonal and spatial distribution of VSLS at the surface, using measurements from NOAA's long-term global monitoring network, and in the tropical troposphere, using recent aircraft measurements – including high-altitude observations from the NASA Global Hawk platform. The models generally capture the observed seasonal cycle of surface CHBr3 and CH2Br2 well, with a strong model–measurement correlation (r  ≥  0.7 at most sites. In a given model, the absolute model–measurement agreement at the surface is highly sensitive to the choice of emissions. Large inter-model differences are apparent when using the same emission inventory, highlighting the challenges faced in evaluating such inventories at the global scale. Across the ensemble, most consistency is found within the tropics where most of the models (8 out of 11 achieve best agreement to

  12. 1982 radon intercomparison exercises at EML

    International Nuclear Information System (INIS)

    Fisenne, I.M.; George, A.C.; Keller, H.W.

    1983-03-01

    This report summarizes the results of two radon measurement intercomparison exercises held in 1982. Sixteen organizations, including five United States federal departments, two state governments, two national laboratories, three universities, three private sector laboratories and Swedish National Institute participated in these exercises. The results indicate good agreement among the participants at the 30 pCi 222 Rn/L level. With the continued interest and cooperation of groups involved in radon measurements, twp intercomparison exercises are planned during 1983

  13. Dosimetry intercomparisons between fast neutron radiotherapy facilities

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.B.; Otte, V.A.

    1975-01-01

    Neutron dosimetry intercomparisons have been made between M.D. Anderson Hospital and Tumor Institute, Naval Research Laboratory, University of Washington Hospital, and Hammersmith Hospital. The parameters that are measured during these visits are: tissue kerma in air, tissue dose at depth of dose maximum, depth dose, beam profiles, neutron/gamma ratios and photon calibrations of ionization chambers. A preliminary report of these intercomparisons will be given including a comparison of the calculation and statement of tumor doses for each institution

  14. Intercomparison of Rn-222 determination from groundwater

    DEFF Research Database (Denmark)

    Vesterbacka, P.; Pettersson, H.; Hanste, U.-M.

    2010-01-01

    An intercomparison exercise on Rn-222 determination in groundwater was organized between eight Nordic laboratories. The individual laboratory results were in most cases within 20% of the median value and within reported uncertainties. Considering the particular difficulties in preparing, transpor......An intercomparison exercise on Rn-222 determination in groundwater was organized between eight Nordic laboratories. The individual laboratory results were in most cases within 20% of the median value and within reported uncertainties. Considering the particular difficulties in preparing...

  15. Intercomparison of TCCON and MUSICA Water Vapour Products

    Science.gov (United States)

    Weaver, D.; Strong, K.; Deutscher, N. M.; Schneider, M.; Blumenstock, T.; Robinson, J.; Notholt, J.; Sherlock, V.; Griffith, D. W. T.; Barthlott, S.; García, O. E.; Smale, D.; Palm, M.; Jones, N. B.; Hase, F.; Kivi, R.; Ramos, Y. G.; Yoshimura, K.; Sepúlveda, E.; Gómez-Peláez, Á. J.; Gisi, M.; Kohlhepp, R.; Warneke, T.; Dohe, S.; Wiegele, A.; Christner, E.; Lejeune, B.; Demoulin, P.

    2014-12-01

    We present an intercomparison between the water vapour products from the Total Carbon Column Observing Network (TCCON) and the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA), two datasets from ground-based Fourier Transform InfraRed (FTIR) spectrometers with good global representation. Where possible, comparisons to radiosondes are also included. The near-infrared TCCON measurements are optimized to provide precise monitoring of greenhouse gases for carbon cycle studies; however, TCCON's retrievals also produce water vapour products. The mid-infrared MUSICA products result from retrievals optimized to give precise and accurate information about H2O, HDO, and δD. The MUSICA water vapour products have been validated by extensive intercomparisons with H2O and δD in-situ measurements made from ground, radiosonde, and aircraft (Schneider et al. 2012, 2014), as well as by intercomparisons with satellite-based H2O and δD remote sensing measurements (Wiegele et al., 2014). This dataset provides a valuable reference point for other measurements of water vapour. This study is motivated by the limited intercomparisons performed for TCCON water vapour products and limited characterisation of their uncertainties. We compare MUSICA and TCCON products to assess the potential for TCCON measurements to contribute to studies of the water cycle, water vapour's role in climate and use as a tracer for atmospheric dynamics, and to evaluate the performance of climate models. The TCCON and MUSICA products result from measurements taken using the same FTIR instruments, enabling a comparison with constant instrumentation. The retrieval techniques differ, however, in their method and a priori information. We assess the impact of these differences and characterize the comparability of the TCCON and MUSICA datasets.

  16. A Methodological Inter-Comparison of Gridded Meteorological Products

    Science.gov (United States)

    Newman, A. J.; Clark, M. P.; Longman, R. J.; Giambelluca, T. W.; Arnold, J.

    2017-12-01

    Here we present a gridded meteorology inter-comparison using the state of Hawaíi as a testbed. This inter-comparison is motivated by two general goals: 1) the broad user community of gridded observation based meteorological fields should be aware of inter-product differences and the reasons they exist, which allows users to make informed choices on product selection to best meet their specific application(s); 2) we want to demonstrate the utility of inter-comparisons to meet the first goal, yet highlight that they are limited to mostly generic statements regarding attribution of differences that limits our understanding of these complex algorithms and obscures future research directions. Hawaíi is a useful testbed because it is a meteorologically complex region with well-known spatial features that are tied to specific physical processes (e.g. the trade wind inversion). From a practical standpoint, there are now several monthly climatological and daily precipitation and temperature datasets available that are being used for impact modeling. General conclusions that have emerged are: 1) differences in input station data significantly influence product differences; 2) prediction of precipitation occurrence is crucial across multiple metrics; 3) derived temperature statistics (e.g. diurnal temperature range) may have large spatial differences across products; and 4) attribution of differences to methodological choices is difficult and may limit the outcomes of these inter-comparisons, particularly from a development viewpoint. Thus, we want to continue to move the community towards frameworks that allow for multiple options throughout the product generation chain and allow for more systematic testing.

  17. Second Latin American intercomparison on internal dose assessment

    International Nuclear Information System (INIS)

    Rojo, A.; Puerta, N.; Gossio, S.; Gomez Parada, I.; Cruz Suarez, R.; Lopez, E.; Medina, C.; Lastra Boylan, J.; Pinheiro Ramos, M.; Mora Ramirez, E.; Alves dos Reis, A.; Yanez, H.; Rubio, J.; Vironneau Janicek, L.; Somarriba Vanegas, F.; Puerta Ortiz, J.; Salas Ramirez, M.; Lopez Bejerano, G.; Da Silva, T.; Miri Oliveira, C.; Teran, M.; Alfaro, M.; Garcia, T.; Angeles, A.; Dure Romero, E.; Farias de Lima, F.

    2016-01-01

    Internal dosimetry intercomparisons are essential for the verification of applied models and the consistency of results. To that aim, the First Regional Intercomparison was organised in 2005, and that results led to the Second Regional Intercomparison Exercise in 2013, which was organised in the frame of the RLA 9/066 and coordinated by Autoridad Regulatoria Nuclear of Argentina. Four simulated cases covering intakes of 131 I, 137 Cs and Tritium were proposed. Nineteen centres from thirteen different countries participated in this exercise. This paper analyses the participants' results in this second exercise in order to test their skills and acquired knowledge, particularly in the application of the IDEAS Guidelines. It is important to highlight the increased number of countries that participated in this exercise compared with the first one and, furthermore, the improvement in the overall performance. The impact of the International Atomic Energy Agency (IAEA) Projects since 2003 has led to a significant enhancement of internal dosimetry capabilities that strengthen the radiation protection of workers. (authors)

  18. SECOND LATIN AMERICAN INTERCOMPARISON ON INTERNAL DOSE ASSESSMENT.

    Science.gov (United States)

    Rojo, A; Puerta, N; Gossio, S; Gómez Parada, I; Cruz Suarez, R; López, E; Medina, C; Lastra Boylan, J; Pinheiro Ramos, M; Mora Ramírez, E; Alves Dos Reis, A; Yánez, H; Rubio, J; Vironneau Janicek, L; Somarriba Vanegas, F; Puerta Ortiz, J; Salas Ramírez, M; López Bejerano, G; da Silva, T; Miri Oliveira, C; Terán, M; Alfaro, M; García, T; Angeles, A; Duré Romero, E; Farias de Lima, F

    2016-09-01

    Internal dosimetry intercomparisons are essential for the verification of applied models and the consistency of results'. To that aim, the First Regional Intercomparison was organised in 2005, and that results led to the Second Regional Intercomparison Exercise in 2013, which was organised in the frame of the RLA 9/066 and coordinated by Autoridad Regulatoria Nuclear of Argentina. Four simulated cases covering intakes of (131)I, (137)Cs and Tritium were proposed. Ninteen centres from thirteen different countries participated in this exercise. This paper analyses the participants' results in this second exercise in order to test their skills and acquired knowledge, particularly in the application of the IDEAS Guidelines. It is important to highlight the increased number of countries that participated in this exercise compared with the first one and, furthermore, the improvement in the overall performance. The impact of the International Atomic Energy Agency (IAEA) Projects since 2003 has led to a significant enhancement of internal dosimetry capabilities that strengthen the radiation protection of workers. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Crop rotation modelling - A European model intercomparison

    DEFF Research Database (Denmark)

    Kollas, Chris; Kersebaum, Kurt C; Nendel, Claas

    2015-01-01

    Diversification of crop rotations is considered an option to increase the resilience of European crop production under climate change. So far, however, many crop simulation studies have focused on predicting single crops in separate one-year simulations. Here, we compared the capability of fiftee...

  20. What is the difference between a 2, 3, 4, or 5 °C world and how good are we at telling this difference? Results from ISI-MIP the first Inter-Sectoral Impact Model Intercomparison Project

    Science.gov (United States)

    Frieler, K.; Huber, V.; Piontek, F.; Schewe, J.; Serdeczny, O.; Warszawski, L.

    2012-12-01

    The Inter-sectoral Impact Model Intercomparison Project (ISI-MIP) aims to synthesize the state-of-the-art knowledge of climate change impacts at different levels of global warming. Over 25 climate impact modelling teams from around the world, working within the agriculture, water, biomes, infrastructure and health sectors, are collaborating to find answers to the question "What is the difference between a 2, 3, 4, or 5 °C world and how good are we at telling this difference?". The analysis is based on common, bias-corrected climate projections, and socio-economic pathways. The first, fast-tracked phase of the ISI-MIP has a focus on global impact models. The project's experimental design is formulated to distinguish the uncertainty introduced by the impact models themselves, from the inherent uncertainty in the climate projections and the variety of plausible socio-economic futures. Novel metrics, developed to emphasize societal impacts, will be used to identify regional 'hot-spots' of climate change impacts, as well as to quantify the cross-sectoral impact of the increasing frequency of extreme events in future climates. We present here first results from the Fast-Track phase of the project covering impact simulations in the biomes, agriculture and water sectors, in which the societal impacts of climate change are quantified for different levels of global warming. We also discuss the design of the scenario set-up and impact indicators chosen to suit the unique cross-sectoral, multi-model nature of the project.

  1. SimilarityExplorer: A visual inter-comparison tool for multifaceted climate data

    Science.gov (United States)

    J. Poco; A. Dasgupta; Y. Wei; W. Hargrove; C. Schwalm; R. Cook; E. Bertini; C. Silva

    2014-01-01

    Inter-comparison and similarity analysis to gauge consensus among multiple simulation models is a critical visualization problem for understanding climate change patterns. Climate models, specifically, Terrestrial Biosphere Models (TBM) represent time and space variable ecosystem processes, for example, simulations of photosynthesis and respiration, using algorithms...

  2. Impact of Spatial Scales on the Intercomparison of Climate Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wei; Steptoe, Michael; Chang, Zheng; Link, Robert; Clarke, Leon; Maciejewski, Ross

    2017-01-01

    Scenario analysis has been widely applied in climate science to understand the impact of climate change on the future human environment, but intercomparison and similarity analysis of different climate scenarios based on multiple simulation runs remain challenging. Although spatial heterogeneity plays a key role in modeling climate and human systems, little research has been performed to understand the impact of spatial variations and scales on similarity analysis of climate scenarios. To address this issue, the authors developed a geovisual analytics framework that lets users perform similarity analysis of climate scenarios from the Global Change Assessment Model (GCAM) using a hierarchical clustering approach.

  3. Intercomparison of PIXE spectrometry software packages

    International Nuclear Information System (INIS)

    2003-02-01

    During the year 2000, an exercise was organized to make a intercomparison of widely available software packages for analysis of particle induced X ray emission (PIXE) spectra. This TECDOC describes the method used in this intercomparison exercise and presents the results obtained. It also gives a general overview of the participating software packages. This includes basic information on their user interface, graphical presentation capabilities, physical phenomena taken in account, way of presenting results, etc. No recommendation for a particular software package or method for spectrum analysis is given. It is intended that the readers reach their own conclusions and make their own choices, according to their specific needs. This TECDOC will be useful to anyone involved in PIXE spectrum analysis. This TECDOC includes a companion CD with the complete set of test spectra used for intercomparison. The test spectra on this CD can be used to test any PIXE spectral analysis software package

  4. Intercomparison of alpha particle spectrometry software packages

    International Nuclear Information System (INIS)

    1999-08-01

    Software has reached an important level as the 'logical controller' at different levels, from a single instrument to an entire computer-controlled experiment. This is also the case for software packages in nuclear instruments and experiments. In particular, because of the range of applications of alpha-particle spectrometry, software packages in this field are often used. It is the aim of this intercomparison to test and describe the abilities of four such software packages. The main objectives of the intercomparison were the ability of the programs to determine the peak areas and the peak area uncertainties, and the statistical control and stability of reported results. In this report, the task, methods and results of the intercomparison are presented in order to asist the potential users of such software and to stimulate the development of even better alpha-particle spectrum analysis software

  5. Intercomparison exercises - a 'must' or a 'need'

    International Nuclear Information System (INIS)

    Paraschiva, Mircea-Valentin; Cherestes, Margareta; Cherestes, Codrut

    2011-01-01

    The national legislation and the IAEA's Basic Safety Standards Series require the implementation of a QA programme for approval of dosimetry services. The implementation of a quality system according to EN ISO/IEC17025:2005 standard is a way to demonstrate that the dosimetry service is technically competent and capable of generating technically valid results. There are around fifty different standards relevant to individual monitoring, which indicates the complexity and difficulty of understanding and using the appropriate standard in routine work. The new recommendations published by European Commission - RP-160 - bring together requirements and guidance given in 96/29/EURATOM Directive, ICRP Publications, ICRU Reports and IAEA technical documents. The aim of these recommendations is to address the growing need for improvement and harmonization of practices and procedures used in individual dosimetry, for a mutual recognition of dose assessments performed by Approved Dosimetry Services across Europe. An intercomparison exercise among dosimetry services is like a performance test. The results of intercomparisons are published but anonimized. In many Member States participation in international intercomparisons is strongly recommended as results can be used to support an application for approval or accreditation. In this paper we present the results of our participation in two intercomparison exercises: EURADOS Intercomparison 2008 and EURADOS Intercomparison 2010. The results are displayed using the 'trumpet curves' (ISO 14146). The corrective actions are presented and also the lessons learned. At first exercise, in 2008, we have participated with one dosimetric system - photographic dosemeter - and at the second one, we have participated with two dosimetric systems: photographic and thermoluminescent. (authors)

  6. EURADOS intercomparison 2012 for neutron dosemeters

    International Nuclear Information System (INIS)

    Fantuzzi, E.; Chevallier, M.A.; Cruz-Suarez, R.; Luszik-Bhadra, M.; Mayer, S.; Thomas, D.J.; Tanner, R.; Vanhavere, F.

    2014-11-01

    EURADOS, within the work performed by Working Group 2 - Harmonization of Individual Monitoring in Europe, has started a self-sustained programme of regular intercomparisons and has successfully executed three intercomparisons for whole body photon dosemeters (IC2008, IC2010, IC2012) and one intercomparison for extremity dosemeters for photon and beta fields (IC2009). In 2012, the EURADOS intercomparison IC2012n was launched for personal neutron dosemeters routinely used to measure personal dose equivalent, Hp(10), in individual monitoring. No systems under development were allowed to participate. IC2012n was carried out by a EURADOS nominated Organization Group (OG) consisting of: Marie- Anne Chevallier (IRSN, F), Rodolfo Cruz-Suarez (IAEA, UN-Vienna), Marlies Luszik-Bhadra (PTB, D), Sabine Mayer (PSI, CH), David J. Thomas (NPL, UK), Rick Tanner (PHE, UK), Filip Vanhavere (SCK-CEN, B) led by a Coordinator, Elena Fantuzzi (ENEA, I). 31 participants registered for the comparison, with 34 dosimetry systems. In total 816 dosemeters were irradiated in selected neutron fields on an ISO slab phantom. The irradiations were performed at 2 European accredited laboratories which are both National Primary Metrology Laboratories for ionizing radiation: NPL (National Physical Laboratory, UK) and PTB (Physikalisch-Technische Bundesanstalt, D). All irradiations were carried out according to the irradiation plan developed by the OG. The overall results show that most, although not all, dosimetric systems perform acceptably well (within a factor of 2) for irradiations with a bare radionuclide source ( 252 Cf at 0 ), whilst more than half of the systems underestimate the reference value for irradiations from non-normal angles of incidence irradiations ( 252 Cf at 45 ) or for simulated workplace fields ( 252 Cf(D 2 O) or 252 Cf source behind a shadow cone). The performance for 250 keV mono-energetic neutron irradiations varies mainly reflecting the detection principle on which the

  7. EURADOS intercomparison 2012 for neutron dosemeters

    Energy Technology Data Exchange (ETDEWEB)

    Fantuzzi, E. [ENEA-Radiation Protection Institute, Bologna (Italy); Chevallier, M.A. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Fontenay-aux-Roses (France); Cruz-Suarez, R. [International Atomic Energy Agency, Vienna (Austria); Luszik-Bhadra, M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Mayer, S. [Paul Scherrer Institute (PSI), Villigen (Switzerland); Thomas, D.J. [National Physical Laboratory (NPL), Teddington (United Kingdom); Tanner, R. [Public Health England, Oxon (United Kingdom); Vanhavere, F. [SCK-CEN, Belgian Nuclear Research Centre, Mol (Belgium)

    2014-11-15

    EURADOS, within the work performed by Working Group 2 - Harmonization of Individual Monitoring in Europe, has started a self-sustained programme of regular intercomparisons and has successfully executed three intercomparisons for whole body photon dosemeters (IC2008, IC2010, IC2012) and one intercomparison for extremity dosemeters for photon and beta fields (IC2009). In 2012, the EURADOS intercomparison IC2012n was launched for personal neutron dosemeters routinely used to measure personal dose equivalent, Hp(10), in individual monitoring. No systems under development were allowed to participate. IC2012n was carried out by a EURADOS nominated Organization Group (OG) consisting of: Marie- Anne Chevallier (IRSN, F), Rodolfo Cruz-Suarez (IAEA, UN-Vienna), Marlies Luszik-Bhadra (PTB, D), Sabine Mayer (PSI, CH), David J. Thomas (NPL, UK), Rick Tanner (PHE, UK), Filip Vanhavere (SCK-CEN, B) led by a Coordinator, Elena Fantuzzi (ENEA, I). 31 participants registered for the comparison, with 34 dosimetry systems. In total 816 dosemeters were irradiated in selected neutron fields on an ISO slab phantom. The irradiations were performed at 2 European accredited laboratories which are both National Primary Metrology Laboratories for ionizing radiation: NPL (National Physical Laboratory, UK) and PTB (Physikalisch-Technische Bundesanstalt, D). All irradiations were carried out according to the irradiation plan developed by the OG. The overall results show that most, although not all, dosimetric systems perform acceptably well (within a factor of 2) for irradiations with a bare radionuclide source ({sup 252}Cf at 0 ), whilst more than half of the systems underestimate the reference value for irradiations from non-normal angles of incidence irradiations ({sup 252}Cf at 45 ) or for simulated workplace fields ({sup 252}Cf(D{sub 2}O) or {sup 252}Cf source behind a shadow cone). The performance for 250 keV mono-energetic neutron irradiations varies mainly reflecting the detection

  8. Computational intercomparison of the mathematical model of a clinical accelerator LINAC 6MV using two different Monte Carlo codes: MCNPx and EGSnrc; Intercomparacao computacional do modelo matematico de um acelerador clinico LINAC 6MV utilizando dois codigos de Monte Carlo diferentes: MCNPx e EGSnrc

    Energy Technology Data Exchange (ETDEWEB)

    Castelo e Silva, L.A., E-mail: castelo@ifsp.edu.br [Instituto Federal de Sao Paulo (IFSP), SP (Brazil); Mendes, M.B.; Goncalves, B.R.; Santos, D.M.M.; Vieira, M.V.; Fonseca, R.L.M.; Zenobio, M.A.F.; Fonseca, T.C.F. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Paixao, L. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2016-07-01

    The main goal of this work is to publish the results of an inter-comparison simulation exercise of a clinical 10 x 10 cm{sup 2} beam model of a 6 MV LINAC using two different Monte Carlo codes: the MCNPX and EGSnrc. Results obtained for the dosimetric parameters PDD{sub 20,10} and TPR{sub 20,10} were compared with experimental data obtained in Radiotherapy and Megavoltage Institute of Minas Gerais. The main challenges on the computational modeling of this system are reported and discussed for didactic purposes in the area of modeling and simulation. (author)

  9. Field intercomparison of prevailing sonic anemometers

    Science.gov (United States)

    Mauder, Matthias; Zeeman, Matthias J.

    2018-01-01

    Three-dimensional sonic anemometers are the core component of eddy covariance systems, which are widely used for micrometeorological and ecological research. In order to characterize the measurement uncertainty of these instruments we present and analyse the results from a field intercomparison experiment of six commonly used sonic anemometer models from four major manufacturers. These models include Campbell CSAT3, Gill HS-50 and R3, METEK uSonic-3 Omni, R. M. Young 81000 and 81000RE. The experiment was conducted over a meadow at the TERENO/ICOS site DE-Fen in southern Germany over a period of 16 days in June of 2016 as part of the ScaleX campaign. The measurement height was 3 m for all sensors, which were separated by 9 m from each other, each on its own tripod, in order to limit contamination of the turbulence measurements by adjacent structures as much as possible. Moreover, the high-frequency data from all instruments were treated with the same post-processing algorithm. In this study, we compare the results for various turbulence statistics, which include mean horizontal wind speed, standard deviations of vertical wind velocity and sonic temperature, friction velocity, and the buoyancy flux. Quantitative measures of uncertainty, such as bias and comparability, are derived from these results. We find that biases are generally very small for all sensors and all computed variables, except for the sonic temperature measurements of the two Gill sonic anemometers (HS and R3), confirming a known transducer-temperature dependence of the sonic temperature measurement. The best overall agreement between the different instruments was found for the mean wind speed and the buoyancy flux.

  10. A model-data intercomparison of CO2 exchange across North America: Results from the North American Carbon Program Site Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Schwalm, C.R.; Williams, C.A.; Schaefer, K.; Anderson, R.; Arain, M.A.; Baker, I.; Black, T.A.; Chen, G.; Ciais, P.; Davis, K. J.; Desai, A. R.; Dietze, M.; Dragoni, D.; Fischer, M.L.; Flanagan, L.B.; Grant, R.F.; Gu, L.; Hollinger, D.; Izaurralde, R.C.; Kucharik, C.; Lafleur, P.M.; Law, B.E.; Li, L.; Li, Z.; Liu, S.; Lokupitiya, E.; Luo, Y.; Ma, S.; Margolis, H.; Matamala, R.; McCaughey, H.; Monson, R. K.; Oechel, W. C.; Peng, C.; Poulter, B.; Price, D.T.; Riciutto, D.M.; Riley, W.J.; Sahoo, A.K.; Sprintsin, M.; Sun, J.; Tian, H.; Tonitto, C.; Verbeeck, H.; Verma, S.B.

    2011-06-01

    Our current understanding of terrestrial carbon processes is represented in various models used to integrate and scale measurements of CO{sub 2} exchange from remote sensing and other spatiotemporal data. Yet assessments are rarely conducted to determine how well models simulate carbon processes across vegetation types and environmental conditions. Using standardized data from the North American Carbon Program we compare observed and simulated monthly CO{sub 2} exchange from 44 eddy covariance flux towers in North America and 22 terrestrial biosphere models. The analysis period spans {approx}220 site-years, 10 biomes, and includes two large-scale drought events, providing a natural experiment to evaluate model skill as a function of drought and seasonality. We evaluate models' ability to simulate the seasonal cycle of CO{sub 2} exchange using multiple model skill metrics and analyze links between model characteristics, site history, and model skill. Overall model performance was poor; the difference between observations and simulations was {approx}10 times observational uncertainty, with forested ecosystems better predicted than nonforested. Model-data agreement was highest in summer and in temperate evergreen forests. In contrast, model performance declined in spring and fall, especially in ecosystems with large deciduous components, and in dry periods during the growing season. Models used across multiple biomes and sites, the mean model ensemble, and a model using assimilated parameter values showed high consistency with observations. Models with the highest skill across all biomes all used prescribed canopy phenology, calculated NEE as the difference between GPP and ecosystem respiration, and did not use a daily time step.

  11. Analysis of the REAL-84 intercomparison exercise

    International Nuclear Information System (INIS)

    1987-10-01

    The document presents the conclusions and the recommendations of the specialists' meeting organized by the IAEA and held in Jackson Hole (USA) between 27-29 May 1987 as a result of the analysis of the REAL-84 intercomparison exercise for improving the accuracy in radiation damage predictions in the neutron environment using good quality input data and proper calculation methods. 6 refs

  12. Intercomparison of high energy neutron personnel dosimeters

    International Nuclear Information System (INIS)

    McDonald, J.C.; Akabani, G.; Loesch, R.M.

    1993-03-01

    An intercomparison of high-energy neutron personnel dosimeters was performed to evaluate the uniformity of the response characteristics of typical neutron dosimeters presently in use at US Department of Energy (DOE) accelerator facilities. It was necessary to perform an intercomparison because there are no national or international standards for high-energy neutron dosimetry. The testing that is presently under way for the Department of Energy Laboratory Accreditation Program (DOELAP) is limited to the use of neutron sources that range in energy from about 1 keV to 2 MeV. Therefore, the high-energy neutron dosimeters presently in use at DOE accelerator facilities are not being tested effectively. This intercomparison employed neutrons produced by the 9 Be(p,n) 9 B interaction at the University of Washington cyclotron, using 50-MeV protons. The resulting neutron energy spectrum extended to a maximum of approximately 50-MeV, with a mean energy of about 20-MeV. Intercomparison results for currently used dosimeters, including Nuclear Type A (NTA) film, thermoluminescent dosimeter (TLD)-albedo, and track-etch dosimeters (TEDs), indicated a wide variation in response to identical doses of high-energy neutrons. Results of this study will be discussed along with a description of plans for future work

  13. Intercomparison of radiocarbon bomb pulse and {sup 210}Pb age models. A study in a peat bog core from North Poland

    Energy Technology Data Exchange (ETDEWEB)

    Piotrowska, Natalia, E-mail: natalia.piotrowska@polsl.p [Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego, 2, Gliwice 44100 (Poland); Vleeschouwer, Francois De; Sikorski, Jaroslaw; Pawlyta, Jacek [Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego, 2, Gliwice 44100 (Poland); Fagel, Nathalie; Roux, Gael Le [Clays and Palaeoclimate Unit, Department of Geology, University of Liege, Allee du 6 Aout, B18, Sart Tilman, Liege 4000 (Belgium); Pazdur, Anna [Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego, 2, Gliwice 44100 (Poland)

    2010-04-15

    Radiocarbon and {sup 210}Pb were measured on the uppermost 40 cm of a Wardenaar peat core retrieved from a Baltic raised bog at Slowinskie Blota (Pomerania, North Poland). This site is the subject of ongoing multiproxy studies covering the last 1300 years. Radiocarbon age model was constructed on the basis of 14 AMS dates obtained on selected Sphagnum spp. fragments, with use of P{sub S}equence tool. We present here a comparison of this model with the age model obtained using CRS model classically applied to {sup 210}Pb measurements.

  14. Reproducibility in cyclostratigraphy: initiating an intercomparison project

    Science.gov (United States)

    Sinnesael, Matthias; De Vleeschouwer, David; Zeeden, Christian; Claeys, Philippe

    2017-04-01

    The study of astronomical climate forcing and the application of cyclostratigraphy have experienced a spectacular growth over the last decades. In the field of cyclostratigraphy a broad range in methodological approaches exist. However, comparative study between the different approaches is lacking. Different cases demand different approaches, but with the growing importance of the field, questions arise about reproducibility, uncertainties and standardization of results. The radioisotopic dating community, in particular, has done far-reaching efforts to improve reproducibility and intercomparison of radioisotopic dates and their errors. To satisfy this need in cyclostratigraphy, we initiate a comparable framework for the community. The aims are to investigate and quantify reproducibility of, and uncertainties related to cyclostratigraphic studies and to provide a platform to discuss the merits and pitfalls of different methodologies, and their applicabilities. With this poster, we ask the feedback from the community on how to design this comparative framework in a useful, meaningful and productive manner. In parallel, we would like to discuss how reproducibility should be tested and what uncertainties should stand for in cyclostratigraphy. On the other hand, we intend to trigger interest for a cyclostratigraphic intercomparison project. This intercomparison project would imply the analysis of artificial and genuine geological records by individual researchers. All participants would be free to determine their method of choice. However, a handful of criterions will be required for an outcome to be comparable. The different results would be compared (e.g. during a workshop or a special session), and the lessons learned from the comparison could potentially be reported in a review paper. The aim of an intercomparison project is not to rank the different methods according to their merits, but to get insight into which specific methods are most suitable for which

  15. Med-CORDEX: a first coordinated inter-comparison of high-resolution and fully coupled regional climate models for the Mediterranean

    Science.gov (United States)

    Somot, Samuel

    2015-04-01

    Due to its geographical, meteorological and oceanographic features, the Mediterranean region can be considered as one of the best place to test and use regional climate modelling tools. It has been chosen as one of the CORDEX sub-domain (MED) leading to the Med-CORDEX initiative. This open and voluntary initiative, financially supported by MISTRALS/HyMeX, has been proposed by the Mediterranean climate modelling research community as a follow-up of previous initiatives. In addition to the CORDEX-like simulations (Atmosphere-RCM, 50 km, ERA-Interim and GCM driven runs), Med-CORDEX includes additional simulations to experiment some of the regional climate modelling current challenges. We present here the status and results of these additional simulations dedicated to the use of (1) very high-resolution Regional Climate Models (RCM, up to 10 km) and (2) fully coupled Regional Climate System Models (RCSM), coupling the various components of the regional climate (atmosphere, land surface and hydrology, river and ocean). Today, Med-CORDEX gathers 23 different modelling groups from 9 different countries (France, Italy, Spain, Serbia, Turkey, Greece, Tunisia, Germany, Hungary) in Europe, Middle-East and North-Africa. They use 12 different atmosphere RCMs including land-surface representation, 4 river models, 10 regional ocean models and 12 different Regional Climate System Models. Almost all the simulations planned (Evaluation, Historical and Scenarios modes) have been completed by the modelling teams. More than half of the runs are archived and freely available for non-commercial use through a dedicated database hosted at ENEA at www.medcordex.eu in common and standardized netcdf format (265,000 files and 3.6 Tb uploaded). This includes atmosphere-only, ocean-only and fully coupled regional climate models. In particular multi-model regional ocean simulations have been archived in a common and standardized format for the first time in the history of the Mediterranean Sea

  16. Evolution of Precipitation Structure During the November DYNAMO MJO Event: Cloud-Resolving Model Intercomparison and Cross Validation Using Radar Observations

    Science.gov (United States)

    Li, Xiaowen; Janiga, Matthew A.; Wang, Shuguang; Tao, Wei-Kuo; Rowe, Angela; Xu, Weixin; Liu, Chuntao; Matsui, Toshihisa; Zhang, Chidong

    2018-04-01

    Evolution of precipitation structures are simulated and compared with radar observations for the November Madden-Julian Oscillation (MJO) event during the DYNAmics of the MJO (DYNAMO) field campaign. Three ground-based, ship-borne, and spaceborne precipitation radars and three cloud-resolving models (CRMs) driven by observed large-scale forcing are used to study precipitation structures at different locations over the central equatorial Indian Ocean. Convective strength is represented by 0-dBZ echo-top heights, and convective organization by contiguous 17-dBZ areas. The multi-radar and multi-model framework allows for more stringent model validations. The emphasis is on testing models' ability to simulate subtle differences observed at different radar sites when the MJO event passed through. The results show that CRMs forced by site-specific large-scale forcing can reproduce not only common features in cloud populations but also subtle variations observed by different radars. The comparisons also revealed common deficiencies in CRM simulations where they underestimate radar echo-top heights for the strongest convection within large, organized precipitation features. Cross validations with multiple radars and models also enable quantitative comparisons in CRM sensitivity studies using different large-scale forcing, microphysical schemes and parameters, resolutions, and domain sizes. In terms of radar echo-top height temporal variations, many model sensitivity tests have better correlations than radar/model comparisons, indicating robustness in model performance on this aspect. It is further shown that well-validated model simulations could be used to constrain uncertainties in observed echo-top heights when the low-resolution surveillance scanning strategy is used.

  17. Future change of climate in South America in the late twenty-first century: intercomparison of scenarios from three regional climate models

    Science.gov (United States)

    Marengo, Jose A.; Ambrizzi, Tercio; Da Rocha, Rosmeri P.; Alves, Lincoln M.; Cuadra, Santiago V.; Valverde, Maria C.; Torres, Roger R.; Santos, Daniel C.; Ferraz, Simone E. T.

    2010-11-01

    Regional climate change projections for the last half of the twenty-first century have been produced for South America, as part of the CREAS (Cenarios REgionalizados de Clima Futuro da America do Sul) regional project. Three regional climate models RCMs (Eta CCS, RegCM3 and HadRM3P) were nested within the HadAM3P global model. The simulations cover a 30-year period representing present climate (1961-1990) and projections for the IPCC A2 high emission scenario for 2071-2100. The focus was on the changes in the mean circulation and surface variables, in particular, surface air temperature and precipitation. There is a consistent pattern of changes in circulation, rainfall and temperatures as depicted by the three models. The HadRM3P shows intensification and a more southward position of the subtropical Pacific high, while a pattern of intensification/weakening during summer/winter is projected by the Eta CCS/RegCM3. There is a tendency for a weakening of the subtropical westerly jet from the Eta CCS and HadRM3P, consistent with other studies. There are indications that regions such of Northeast Brazil and central-eastern and southern Amazonia may experience rainfall deficiency in the future, while the Northwest coast of Peru-Ecuador and northern Argentina may experience rainfall excesses in a warmer future, and these changes may vary with the seasons. The three models show warming in the A2 scenario stronger in the tropical region, especially in the 5°N-15°S band, both in summer and especially in winter, reaching up to 6-8°C warmer than in the present. In southern South America, the warming in summer varies between 2 and 4°C and in winter between 3 and 5°C in the same region from the 3 models. These changes are consistent with changes in low level circulation from the models, and they are comparable with changes in rainfall and temperature extremes reported elsewhere. In summary, some aspects of projected future climate change are quite robust across this set of

  18. Intercomparison of Meteorological Forcing Data from Empirical and Mesoscale Model Sources in the N.F. American River Basin in northern California

    Science.gov (United States)

    Wayand, N. E.; Hamlet, A. F.; Hughes, M. R.; Feld, S.; Lundquist, J. D.

    2012-12-01

    The data required to drive distributed hydrological models is significantly limited within mountainous terrain due to a scarcity of observations. This study evaluated three common configurations of forcing data: a) one low-elevation station, combined with empirical techniques, b) gridded output from the Weather Research and Forecasting (WRF) model, and c) a combination of the two. Each configuration was evaluated within the heavily-instrumented North Fork American River Basin in northern California, during October-June 2000-2010. Simulations of streamflow and snowpack using the Distributed Hydrology Soil and Vegetation Model (DHSVM) highlighted precipitation and radiation as variables whose sources resulted in significant differences. The best source of precipitation data varied between years. On average, the performance of WRF and the single station distributed using the Parameter Regression on Independent Slopes Model (PRISM), were not significantly different. The average percent biases in simulated streamflow were 3.4% and 0.9%, for configurations a) and b) respectively, even though precipitation compared directly with gauge measurements was biased high by 6% and 17%, suggesting that gauge undercatch may explain part of the bias. Simulations of snowpack using empirically-estimated long-wave irradiance resulted in melt rates lower than those observed at high-elevation sites, while at lower-elevations the same forcing caused significant mid-winter melt that was not observed (Figure 1). These results highlight the complexity of how forcing data sources impact hydrology over different areas (high vs. low elevation snow) and different time-periods. Overall, results support the use of output from the WRF model over empirical techniques in regions with limited station data. FIG. 1. (a,b) Simulated SWE from DHSVM compared to observations at the Sierra Snow Lab (2100m) and Blue Canyon (1609m) during 2008 - 2009. Modeled (c,d) internal pack temperature, (e,f) downward

  19. The sensitivity of Alpine summer convection to surrogate climate change: an intercomparison between convection-parameterizing and convection-resolving models

    Directory of Open Access Journals (Sweden)

    M. Keller

    2018-04-01

    Full Text Available Climate models project an increase in heavy precipitation events in response to greenhouse gas forcing. Important elements of such events are rain showers and thunderstorms, which are poorly represented in models with parameterized convection. In this study, simulations with 12 km horizontal grid spacing (convection-parameterizing model, CPM and 2 km grid spacing (convection-resolving model, CRM are employed to investigate the change in the diurnal cycle of convection with warmer climate. For this purpose, simulations of 11 days in June 2007 with a pronounced diurnal cycle of convection are compared with surrogate simulations from the same period. The surrogate climate simulations mimic a future climate with increased temperatures but unchanged relative humidity and similar synoptic-scale circulation. Two temperature scenarios are compared: one with homogeneous warming (HW using a vertically uniform warming and the other with vertically dependent warming (VW that enables changes in lapse rate.The two sets of simulations with parameterized and explicit convection exhibit substantial differences, some of which are well known from the literature. These include differences in the timing and amplitude of the diurnal cycle of convection, and the frequency of precipitation with low intensities. The response to climate change is much less studied. We can show that stratification changes have a strong influence on the changes in convection. Precipitation is strongly increasing for HW but decreasing for the VW simulations. For cloud type frequencies, virtually no changes are found for HW, but a substantial reduction in high clouds is found for VW. Further, we can show that the climate change signal strongly depends upon the horizontal resolution. In particular, significant differences between CPM and CRM are found in terms of the radiative feedbacks, with CRM exhibiting a stronger negative feedback in the top-of-the-atmosphere energy budget.

  20. The sensitivity of Alpine summer convection to surrogate climate change: an intercomparison between convection-parameterizing and convection-resolving models

    Science.gov (United States)

    Keller, Michael; Kröner, Nico; Fuhrer, Oliver; Lüthi, Daniel; Schmidli, Juerg; Stengel, Martin; Stöckli, Reto; Schär, Christoph

    2018-04-01

    Climate models project an increase in heavy precipitation events in response to greenhouse gas forcing. Important elements of such events are rain showers and thunderstorms, which are poorly represented in models with parameterized convection. In this study, simulations with 12 km horizontal grid spacing (convection-parameterizing model, CPM) and 2 km grid spacing (convection-resolving model, CRM) are employed to investigate the change in the diurnal cycle of convection with warmer climate. For this purpose, simulations of 11 days in June 2007 with a pronounced diurnal cycle of convection are compared with surrogate simulations from the same period. The surrogate climate simulations mimic a future climate with increased temperatures but unchanged relative humidity and similar synoptic-scale circulation. Two temperature scenarios are compared: one with homogeneous warming (HW) using a vertically uniform warming and the other with vertically dependent warming (VW) that enables changes in lapse rate. The two sets of simulations with parameterized and explicit convection exhibit substantial differences, some of which are well known from the literature. These include differences in the timing and amplitude of the diurnal cycle of convection, and the frequency of precipitation with low intensities. The response to climate change is much less studied. We can show that stratification changes have a strong influence on the changes in convection. Precipitation is strongly increasing for HW but decreasing for the VW simulations. For cloud type frequencies, virtually no changes are found for HW, but a substantial reduction in high clouds is found for VW. Further, we can show that the climate change signal strongly depends upon the horizontal resolution. In particular, significant differences between CPM and CRM are found in terms of the radiative feedbacks, with CRM exhibiting a stronger negative feedback in the top-of-the-atmosphere energy budget.

  1. Intercomparison of Satellite Derived Gravity Time Series with Inferred Gravity Time Series from TOPEX/POSEIDON Sea Surface Heights and Climatological Model Output

    Science.gov (United States)

    Cox, C.; Au, A.; Klosko, S.; Chao, B.; Smith, David E. (Technical Monitor)

    2001-01-01

    The upcoming GRACE mission promises to open a window on details of the global mass budget that will have remarkable clarity, but it will not directly answer the question of what the state of the Earth's mass budget is over the critical last quarter of the 20th century. To address that problem we must draw upon existing technologies such as SLR, DORIS, and GPS, and climate modeling runs in order to improve our understanding. Analysis of long-period geopotential changes based on SLR and DORIS tracking has shown that addition of post 1996 satellite tracking data has a significant impact on the recovered zonal rates and long-period tides. Interannual effects such as those causing the post 1996 anomalies must be better characterized before refined estimates of the decadal period changes in the geopotential can be derived from the historical database of satellite tracking. A possible cause of this anomaly is variations in ocean mass distribution, perhaps associated with the recent large El Nino/La Nina. In this study, a low-degree spherical harmonic gravity time series derived from satellite tracking is compared with a TOPEX/POSEIDON-derived sea surface height time series. Corrections for atmospheric mass effects, continental hydrology, snowfall accumulation, and ocean steric model predictions will be considered.

  2. Robustness and sensitivities of central U.S. summer convection in the super-parameterized CAM: Multi-model intercomparison with a new regional EOF index

    Science.gov (United States)

    Kooperman, Gabriel J.; Pritchard, Michael S.; Somerville, Richard C. J.

    2013-06-01

    Mesoscale convective systems (MCSs) can bring up to 60% of summer rainfall to the central United States but are not simulated by most global climate models. In this study, a new empirical orthogonal function based index is developed to isolate the MCS activity, similar to that developed by Wheeler and Hendon (2004) for the Madden-Julian Oscillation. The index is applied to compactly compare three conventional- and super-parameterized (SP) versions (3.0, 3.5, and 5.0) of the National Center for Atmospheric Research Community Atmosphere Model (CAM). Results show that nocturnal, eastward propagating convection is a robust effect of super-parameterization but is sensitive to its specific implementation. MCS composites based on the index show that in SP-CAM3.5, convective MCS anomalies are unrealistically large scale and concentrated, while surface precipitation is too weak. These aspects of the MCS signal are improved in the latest version (SP-CAM5.0), which uses high-order microphysics.

  3. The Vertical Structure of Relative Humidity and Ozone in the Tropical Upper Troposphere: Intercomparisons Among In Situ Observations, A-Train Measurements and Large-Scale Models

    Science.gov (United States)

    Selkirk, Henry B.; Manyin, Michael; Douglass, Anne R.; Oman, Luke; Pawson, Steven; Ott, Lesley; Benson, Craig; Stolarski, Richard

    2010-01-01

    In situ measurements in the tropics have shown that in regions of active convection, relative humidity with respect to ice in the upper troposphere is typically close to saturation on average, and supersaturations greater than 20% are not uncommon. Balloon soundings with the cryogenic frost point hygrometer (CFH) at Costa Rica during northern summer, for example, show this tendency to be strongest between 11 and 15.5 km (345-360 K potential temperature, or approximately 250-120 hPa). this is the altitude range of deep convective detrainment. Additionally, simultaneous ozonesonde measurements show that stratospheric air (O3 greater than 150 ppbv) can be found as low as approximately 14 km (350 K/150 hPa). In contrast, results from northern winter show a much drier upper troposphere and little penetration of stratospheric air below the tropopause at 17.5 km (approximately 383 K). We show that these results are consistent with in situ measurements from the Measurement of Ozone and water vapor by Airbus In-service airCraft (MOZAIC) program which samples a wider, though still limited, range of tropical locations. To generalize to the tropics as a whole, we compare our insitu results to data from two A-Train satellite instruments, the Atmospheric Infrared Sounder (AIRS) and the Microwave Limb Sounder (MLS) on the Aqua and Aura satellites respectively. Finally, we examine the vertical structure of water vapor, relative humidity and ozone in the NASA Goddard MERRA analysis, an assimilation dataset, and a new version of the GEOS CCM, a free-running chemistry-climate model. We demonstrate that conditional probability distributions of relative humidity and ozone are a sensitive diagnostic for assessing the representation of deep convection and upper troposphere/lower stratosphere mixing processes in large-scale analyses and climate models.

  4. Results from 2010 Caliban Criticality Dosimetry Intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Veinot, K. G.

    2011-10-12

    The external dosimetry program participated in a criticality dosimetry intercomparison conducted at the Caliban facility in Valduc, France in 2010. Representatives from the dosimetry and instrumentation groups were present during testing which included irradiations of whole-body beta/gamma (HBGT) and neutron thermoluminescent dosimeters (TLDs), a fixed nuclear accident dosimeter (FNAD), electronic alarming dosimeters, and a humanoid phantom filled with reference man concentrations of sodium. This report reviews the testing procedures, preparations, irradiations, and presents results of the tests.

  5. Environmental radioactivity measurement intercomparison exercise 1990

    International Nuclear Information System (INIS)

    Jerome, S.M.

    1991-05-01

    In a recent national intercomparison exercise, 49 laboratories involved in making environmental radioactivity measurements took part in the analysis of samples supplied by the National Physical Laboratory (NPL) in the United Kingdom. There were two sets of samples; one containing pure β-emitters and one containing β/γ-emitters. Two thirds of the participants measured the β/γ-emitter sample only, the remainder measured both. The results are presented. (author)

  6. Atmospheric Correction Inter-Comparison Exercise

    Directory of Open Access Journals (Sweden)

    Georgia Doxani

    2018-02-01

    Full Text Available The Atmospheric Correction Inter-comparison eXercise (ACIX is an international initiative with the aim to analyse the Surface Reflectance (SR products of various state-of-the-art atmospheric correction (AC processors. The Aerosol Optical Thickness (AOT and Water Vapour (WV are also examined in ACIX as additional outputs of AC processing. In this paper, the general ACIX framework is discussed; special mention is made of the motivation to initiate the experiment, the inter-comparison protocol, and the principal results. ACIX is free and open and every developer was welcome to participate. Eventually, 12 participants applied their approaches to various Landsat-8 and Sentinel-2 image datasets acquired over sites around the world. The current results diverge depending on the sensors, products, and sites, indicating their strengths and weaknesses. Indeed, this first implementation of processor inter-comparison was proven to be a good lesson for the developers to learn the advantages and limitations of their approaches. Various algorithm improvements are expected, if not already implemented, and the enhanced performances are yet to be assessed in future ACIX experiments.

  7. Mobile Radiological Laboratories Intercomparison Measurements - Chernobyl

    International Nuclear Information System (INIS)

    Martincic, R.; Glavic-Cindro, D.; Korun, M.; Pucelj, B.; Vodenik, B.

    2001-01-01

    Full text: In last decade different institutions in European countries have organised periodic intercomparison exercises of mobile radiological laboratories to improve the preparedness of emergency monitoring teams. The 12th Regular Workshop on Mobile Radiological Laboratories was held in Exclusion Zone of the Chernobyl NPP, Ukraine from September 13 to September 18, 1999 under the acronym MORAL-12. The European Centre of Technological Safety (TESEC), Kiev, Ukraine and J. Stefan Institute, Ljubljana, Slovenia organised Intercomparison Measurements 99 jointly under the auspices of the International Atomic Energy Agency (IAEA). Nineteen teams from 9 countries and IAEA participated in the Workshop. Six field and personal and equipment contamination control exercises were prepared and conducted at two measuring sites with very different ambient dose rate levels. The Workshop pointed out that such exercises are very valuable for rapid, efficient and harmonised emergency response in case of nuclear or radiological emergency. The teams had an opportunity to test their ability to perform field measurements in the contaminated environment, and to report results on the spot, as well as to test their emergency preparedness and persistence. They gained new experiences for fieldwork under stress conditions. An overview and results of these intercomparison measurements are presented and lessons learned are discussed. (author)

  8. Intercomparison campaign of Contracted Partner Institutes 1997

    International Nuclear Information System (INIS)

    Reinen, H.A.J.M.; Tijsmans, M.H.; Van Tuinen, S.T.; Overwater, R.M.W.; Aldenkamp, F.J.

    1998-01-01

    The Dutch National Plan for Nuclear Emergency Planning and Response (EPR) is trained frequently. Intercomparison campaigns and exercises are part of this training for the Contracted Partner Institutes (CPI). The results of an intercomparison campaign in 1997 for the CPI are reported. Two carbon cartridges, one contaminated homogeneously and one inhomogeneously with 131 I, and a water sample contaminated with 134 Cs and 137 Cs were analysed by means of gamma spectroscopy. The results had to be faxed to RIVM within the time limits prescribed in the emergency protocols for CPI, i.e. 2 hours for the cartridges and 24 hours for the water sample. Most CPI reported in time. The results for the inhomogeneously contaminated cartridge are within 25% from the accepted reference value (ARV). For the homogeneously contaminated cartridge the results are within 40% from the ARV. In reality, the contamination of the cartridge will have an exponential profile, with most of the activity in the first few millimeters. In this situation results can be expected to be within 20% from the true value. The results for the water sample are within 5% from the ARV. Although most CPI have applied corrections for coincidence summing for 134 Cs there is still a systematic error of 4% for this nuclide. In regard of the requirements for measurements during emergency situations, the results of this intercomparison campaign are satisfactory

  9. On the methodology of the intercomparison of TND evaluations

    International Nuclear Information System (INIS)

    Yiftah, S.; Caner, M.; Gur, Y.

    1979-03-01

    The paper presents the problems which arise when two independent complete nuclear data evaluations of the same nuclide are available. A detailed intercomparison of the evaluations can be a multi-levelled exercise of considerable detail, the stages of which cannot always be performed. However, a detailed intercomparison can be a rich source for improving considerably the nuclear data used for the different applications. Preliminary examples of intercomparison are given for illustrative purpose. (B.G.)

  10. Neutron dosimetry intercomparison run for verification of the neutron fluence

    International Nuclear Information System (INIS)

    Penev, I.; Kinova, L.

    2001-01-01

    For the neutron fluence verification the intercomparison runs Balakovo and KORPUS have been carried out. The participation in the international intercomparison runs shows that in order to more precisely verify the calculated values of the neutron fluence more intercomparison exercises are necessary. Due to such exercises the results improved after calibration of Nb performed and are in a very good agreement with RIIAR results in spite of the different approaches in the determination of its activity

  11. Results of the IAEA/RCA personal dosemeter intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Norio; Momose, Takumaro; Hayashi, Naomi [Environment and Safety Division, Tokai Works, Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

    2000-06-01

    The intercomparison of personal dosemeters for photon was carried out between 1990 and 1996 as part of the IAEA/RCA 'strengthening of radiation protection infrastructure' project. Japan Nuclear Cycle Development Institute participated in the intercomparison as one of the in-house personal dosimetry service organizations in Japan and also served the host irradiating laboratory. This report summarizes the dose evaluation results obtained from the JNC-TLD badges in the past four intercomparison programs. In the latest intercomparison the evaluated doses agreed to the reference doses with an accuracy of 10%. (author)

  12. Program for Climate Model Diagnosis and Intercomparison

    Data.gov (United States)

    Federal Laboratory Consortium — PCMDI was established in 1989 at the Lawrence Livermore National Laboratory (LLNL), located in the San Francisco Bay area, in California. Our staff includes research...

  13. Dosimetry intercomparisons in European medical device sterilization plants

    DEFF Research Database (Denmark)

    Miller, A.; Sharpe, P.H.G.

    2000-01-01

    Dosimetry intercomparisons have been carried out involving two-thirds of all European radiation sterilization facilities. Dosimeters for the intercomparisons were supplied by two accredited calibration laboratories. The results show good agreement, and indicate overall dosimetry accuracy of the o...... of the order of +/-5% (1 sigma) for both Co-60 and electron beam plants. (C) 2000 Elsevier Science Ltd. All rights reserved....

  14. DOE Radiological Calibrations Intercomparison Program: Results of fiscal year 1987

    International Nuclear Information System (INIS)

    Cummings, F.M.; McDonald, J.C.

    1988-06-01

    This report presents the FY 1987 results of the radiological calibrations intercomparison program. The intercomparison operation is discussed, and the equipment is described, particularly the instrument set, the beta source set, and relevant calculations. Solutions to problems and improvements in the program are suggested, and conclusions are then introduced. 9 refs., 3 figs., 8 tabs

  15. The intercomparison of aerosol codes

    International Nuclear Information System (INIS)

    Dunbar, I.H.; Fermandjian, J.; Gauvain, J.

    1988-01-01

    The behavior of aerosols in a reactor containment vessel following a severe accident could be an important determinant of the accident source term to the environment. Various processes result in the deposition of the aerosol onto surfaces within the containment, from where they are much less likely to be released. Some of these processes are very sensitive to particle size, so it is important to model the aerosol growth processes: agglomeration and condensation. A number of computer codes have been written to model growth and deposition processes. They have been tested against each other in a series of code comparison exercises. These exercises have investigated sensitivities to physical and numerical assumptions and have also proved a useful means of quality control for the codes. Various exercises in which code predictions are compared with experimental results are now under way

  16. Atmospheric Correction Inter-comparison Exercise (ACIX)

    Science.gov (United States)

    Vermote, E.; Doxani, G.; Gascon, F.; Roger, J. C.; Skakun, S.

    2017-12-01

    The free and open data access policy to Landsat-8 (L-8) and Sentinel-2 (S-2) satellite imagery has encouraged the development of atmospheric correction (AC) approaches for generating Bottom-of-Atmosphere (BOA) products. Several entities have started to generate (or plan to generate in the short term) BOA reflectance products at global scale for L-8 and S-2 missions. To this end, the European Space Agency (ESA) and National Aeronautics and Space Administration (NASA) have initiated an exercise on the inter-comparison of the available AC processors. The results of the exercise are expected to point out the strengths and weaknesses, as well as communalities and discrepancies of various AC processors, in order to suggest and define ways for their further improvement. In particular, 11 atmospheric processors from five different countries participate in ACIX with the aim to inter-compare their performance when applied to L-8 and S-2 data. All the processors should be operational without requiring parametrization when applied on different areas. A protocol describing in details the inter-comparison metrics and the test dataset based on the AERONET sites has been agreed unanimously during the 1st ACIX workshop in June 2016. In particular, a basic and an advanced run of each of the processor were requested in the frame of ACIX, with the aim to draw robust and reliable conclusions on the processors' performance. The protocol also describes the comparison metrics of the aerosol optical thickness and water vapour products of the processors with the corresponding AERONET measurements. Moreover, concerning the surface reflectances, the inter-comparison among the processors is defined, as well as the comparison with the MODIS surface reflectance and with a reference surface reflectance product. Such a reference product will be obtained using the AERONET characterization of the aerosol (size distribution and refractive indices) and an accurate radiative transfer code. The inter-comparison

  17. Intercomparison of radiation dosimeters for individual monitoring

    International Nuclear Information System (INIS)

    1993-05-01

    The Co-ordinated Research Programme on Intercomparison for Individual Monitoring was established to provide participants with an opportunity to assess (1) their ability to measure external photon radiation fields and (2) the potential impact of introduction of the new operational quantities on their dosimetry programmes. Twenty-four laboratories from 18 IAEA Member States and three international organizations, including the IAEA, participated. The results of phase II of the CRP are presented in this document, which includes a compilation of the presentations and conclusions from the meeting. Refs, figs and tabs

  18. Radiocarbon intercomparison program for Chauvet Cave

    International Nuclear Information System (INIS)

    Cuzange, M.T.; Delque-Kolic, E.; Oberlin, C.; Goslar, T.; Grootes, P.M.; Nadeau, M.J.; Higham, T.; Ramsey, C.B.; Kaltnecker, E.; Paterne, M.; Valladas, H.; Van der Plicht, J.; Van der Plicht, J.; Clottes, J.; Geneste, J.M.

    2007-01-01

    We present the first results of an accelerator mass spectrometry (AMS) radiocarbon intercomparison program on 3 different charcoal samples collected in one of the hearths of the Megaceros gallery of Chauvet Cave (Ardeche, France). This cave, rich in parietal decoration, is important for the study of the appearance and evolution of prehistoric art because certain drawings have been 14 C dated to the Aurignacian period at the beginning of the Upper Paleolithic. The new dates indicate an age of about 32,000 BP, which is consistent with this attribution and in agreement with the results from the same sector of the cave measured previously at the Laboratoire des Sciences du Climat et de l'Environnement (LSCE). Six laboratories were involved in the intercomparison. Samples were measured in 4 AMS facilities: Center for Isotope Research, Groningen University, the Netherlands; the Oxford Radiocarbon Accelerator Unit, UK; the Centre de datation par le carbone 14, Univ. Claude Bernard Lyon 1, France (measured by AMS facilities of Poznan University, Poland); and the LSCE, UMR CEA-CNRS-UVSQ, France (measured by the Leibniz-Labor of Christian-Albrechts-Universitat Kiel, Germany). (authors)

  19. Summary of 'IAEA intercomparison of IBA software'

    International Nuclear Information System (INIS)

    Barradas, N.P.; Arstila, K.; Battistig, G.; Bianconi, M.; Dytlewski, N.; Jeynes, C.; Kotai, E.; Lulli, G.; Mayer, M.; Rauhala, E.; Szilagyi, E.; Thompson, M.

    2008-01-01

    The International Atomic Energy Agency has sponsored a formal intercomparison exercise for the seven depth profiling ion beam analysis codes, which are: GISA, RUMP, RBX, DEPTH, DataFurnace, SIMNRA and MCERD. This intercomparison is published in Nucl. Instr. and Meth. B [N.P. Barradas, K. Arstila, G. Battistig, M. Bianconi, N. Dytlewski, C. Jeynes, E. Kotai, G. Lulli, M. Mayer, E. Rauhala, E. Szilagyi, M. Thompson, Nucl. Instr. and Meth. B 262 (2007) 281-303] and summarised here. The codes implement all known physical effects and they are all evaluated. We demonstrate that there is agreement between codes often better than 0.1%; and also detailed agreement with real spectra, showing in particular that the SRIM 2003 stopping powers for Si are correct to 0.6% for 1.5 MeV He. For the case of heavy ion elastic recoil detection (HI-ERD) the single scattering codes performed poorly for scattered particles, although recoiled particles were calculated correctly

  20. Thorium in the workplace measurement intercomparison

    International Nuclear Information System (INIS)

    Modna, D.K.; Jerome, S.M.; White, M.A.; Woods, M.J.

    2000-01-01

    The monitoring of radionuclides in the nuclear industry has been recognized as the most straightforward way of assessing health and safety issues associated with the exposure of the workforce to potentially harmful radiation doses. Much of this is achieved by measurements in the workplace itself and by the bioassay and monitoring of workers in the industry. However, there also exists a significant 'non-nuclear' industry where workers are exposed to radioactive materials, for example where this involves thorium, which is made wide use of in the aerospace and other high technology industries. As such work involves the processing of thorium bearing materials, the workforce is potentially exposed to 232 Th and its daughter nuclides. Thus, to monitor the workforce effectively, it is important to be able to measure both 232 Th and the decay products of 232 Th where they are in an unknown state of radioactive equilibrium and this is where monitoring laboratories may experience some difficulty. Accordingly, the Health and Safety Laboratory in the UK has organized a EC wide project on the monitoring of thorium in the 'non-nuclear' workplace; this project is currently ongoing. We report the results of the first intercomparison of this project involving two solutions of 232 Th, one in radioactive equilibrium and one not in equilibrium with its daughters. The results are presented with some comments on how this intercomparison has progressed and how these first results will inform the rest of the project

  1. AMBER and Ecolego Intercomparisons using Calculations from SR 97

    International Nuclear Information System (INIS)

    Maul, Philip; Robinson, Peter; Avila, Rodolfo; Broed, Robert; Pereira, Antonio

    2003-08-01

    The AMBER compartmental modelling software has been used by Quintessa in undertaking Performance Assessment (PA) calculations for SKI for the last four years. In particular, it was used in helping to identify key issues in the safety case for SFR 1. SSI and the Norwegian Radiation Protection Authority (NRPA) are supporting the development of Ecolego which is based on the Matlab/Simulink general purpose modelling software and provides a user-friendly Graphical User Interface which is particularly suitable for undertaking PA calculations. At SKI/SSI expert group meetings in September 2002, Quintessa presented some radionuclide transport calculations for a deep repository for spent fuel using AMBER. Comparisons were presented with calculations undertaken by SKB in their SR 97 study. It was agreed that it would be useful to undertake some intercomparison calculations using AMBER and Ecolego based on calculation cases considered in SR 97. The reasons for undertaking such intercomparisons include: 1. to give confidence in the use of AMBER and Ecolego for whole system PA calculations for a deep repository; and 2. to provide SKI and SSI with an understanding of some of the technical issues raised by seeking to repeat the SR 97 calculations with different models and software. This report documents the intercomparison calculations that have been undertaken. The main conclusions that have been drawn are: 1. Both modelling packages could successfully reproduce SKB's SR 97 calculations for the near field, geosphere and biosphere. 2. The results of the deterministic calculations for the near field and both deterministic and probabilistic calculations for the biosphere, where AMBER and Ecolego used compartment models, were typically in agreement to within one significant figure. The identical results for the calculated equilibrium inventories in Bay sediments illustrate that the calculations by AMBER and Ecolego are essentially the same when the compartment models are identical

  2. The 1996 Radon Intercomparison Exercise at PSI

    International Nuclear Information System (INIS)

    Schuler, C.; Butterweck-Dempewolf, G.

    1997-05-01

    The 1996 Radon Intercomparison Exercise at PSI was organized by the PSI Reference Laboratory for Radon Gas Activity Concentration Measurements. A total of 14 laboratories, companies and institutions participated with radon gas detectors and measuring instruments. The detectors and instruments were exposed in the PSI radon chamber during seven days in a reference atmosphere with an average radon gas concentration of about 6000 Bqm -3 . Comparison of the results of electret ionization chambers, track etch detectors and measuring instruments with the PSI target value showed the criteria for traceability and reproducibility demanded by the Federal Office for Health for the acknowledgement of Swiss Radon Gas Measurement Laboratories to be fulfilled for all participants. Exposure of track etch detectors stored for more than one year demonstrated that this detector type can suffer sensitivity loss by a too long storage period. (author) figs., tabs., refs

  3. Intercomparison measurements with albedo neutron dosimeters

    International Nuclear Information System (INIS)

    Alberts, W.G.; Kluge, H.

    1994-01-01

    Since the introduction of the albedo dosimeter as the official personal neutron dosimeter the dosimetry services concerned have participated in intercomparison measurements at the PTB. Their albedo dosimeters were irradiated in reference fields produced by unmoderated and D 2 O-moderated 252 Cf neutron sources in the standard irradiation facility of the PTB. Six fields with fluences different in energy and angle distribution could be realised in order to determine the response of the albedo dosimeter. The dose equivalent values evaluated by the services were compared with the reference values of the PTB for the directional dose equivalent H'(10). The results turned out to be essentially dependent on the evaluation method and the choice of the calibration factors. (orig.) [de

  4. Czech results at criticality dosimetry intercomparison 2002.

    Science.gov (United States)

    Frantisek, Spurný; Jaroslav, Trousil

    2004-01-01

    Two criticality dosimetry systems were tested by Czech participants during the intercomparison held in Valduc, France, June 2002. The first consisted of the thermoluminescent detectors (TLDs) (Al-P glasses) and Si-diodes as passive neutron dosemeters. Second, it was studied to what extent the individual dosemeters used in the Czech routine personal dosimetry service can give a reliable estimation of criticality accident exposure. It was found that the first system furnishes quite reliable estimation of accidental doses. For routine individual dosimetry system, no important problems were encountered in the case of photon dosemeters (TLDs, film badge). For etched track detectors in contact with the 232Th or 235U-Al alloy, the track density saturation for the spark counting method limits the upper dose at approximately 1 Gy for neutrons with the energy >1 MeV.

  5. Result of the intercomparison exercise on radon measuring instruments and radon detectors 'bev- radon ring 2005'

    International Nuclear Information System (INIS)

    Baumgartner, A.; Maringer, F.J.; Michai, P.; Kreuziger, M.

    2006-01-01

    In spring 2005 the Federal Office of Metrology and Surveying (B.E.V.) invited all in Austria working radon measuring institutes to an intercomparison exercise at the radon calibration laboratory in the Arsenal. The aim of this intercomparison was on the one hand an objective inquiry and documentation of the current metrological potential on the section of radon measurement in Austria - both quantitative and qualitative- and on the other hand an initiative for the participating laboratories to optimize and improve their applied calibration-, measurement and analyse technique. Ten contacted Austrian radon laboratories were prepared to participate on the radon intercomparison exercise. The intercomparison exercise was carried out from 14. till 29. June at the radon calibration laboratory in the Arsenal of the B.E.V.. As radon emanation source a five stepped arranged, at the Arsenal built radon source was used. The source ( A.D.O.T.T.O. 1 is filled with a certified Ra- 226-standard solution of the Czech Metrological Institute (C.M.I.), Prag. A simple statistic based model was used for the evaluation and assessment of the results from the participants, which consider the statistic nature of the radioactive decay combined uncertainty. Altogether 183 measuring instruments participated the intercomparison exercise. Two reference measuring instruments, 22 active and 159 passive measuring instruments. The active measuring instruments formed 6 types of instruments and as passive radon detectors were 7 different types used from the participants. The positioning of the radon measuring instruments and detectors in the radon calibration laboratory was executed in regard to statistic points of view. From the active measuring instruments 17 could qualify and from the passive methods six from eight participants were in compliance to the given criteria. Radon measurements, which could have financial and economics relating implications (e.g. architectural redevelopment or

  6. The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses

    Directory of Open Access Journals (Sweden)

    H. E. Thornton

    2009-02-01

    Full Text Available This paper presents results from the first detailed intercomparison of stratosphere-lower mesosphere water vapour analyses; it builds on earlier results from the EU funded framework V "Assimilation of ENVISAT Data" (ASSET project. Stratospheric water vapour plays an important role in many key atmospheric processes and therefore an improved understanding of its daily variability is desirable. With the availability of high resolution, good quality Michelson Interferometer for Passive Atmospheric Sounding (MIPAS water vapour profiles, the ability of four different atmospheric models to assimilate these data is tested. MIPAS data have been assimilated over September 2003 into the models of the European Centre for Medium Range Weather Forecasts (ECMWF, the Belgian Institute for Space and Aeronomy (BIRA-IASB, the French Service d'Aéronomie (SA-IPSL and the UK Met Office. The resultant middle atmosphere humidity analyses are compared against independent satellite data from the Halogen Occultation Experiment (HALOE, the Polar Ozone and Aerosol Measurement (POAM III and the Stratospheric Aerosol and Gas Experiment (SAGE II. The MIPAS water vapour profiles are generally well assimilated in the ECMWF, BIRA-IASB and SA systems, producing stratosphere-mesosphere water vapour fields where the main features compare favourably with the independent observations. However, the models are less capable of assimilating the MIPAS data where water vapour values are locally extreme or in regions of strong humidity gradients, such as the southern hemisphere lower stratosphere polar vortex. Differences in the analyses can be attributed to the choice of humidity control variable, how the background error covariance matrix is generated, the model resolution and its complexity, the degree of quality control of the observations and the use of observations near the model boundaries. Due to the poor performance of the Met Office analyses the results are not included in

  7. The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses

    Science.gov (United States)

    Thornton, H. E.; Jackson, D. R.; Bekki, S.; Bormann, N.; Errera, Q.; Geer, A. J.; Lahoz, W. A.; Rharmili, S.

    2009-02-01

    This paper presents results from the first detailed intercomparison of stratosphere-lower mesosphere water vapour analyses; it builds on earlier results from the EU funded framework V "Assimilation of ENVISAT Data" (ASSET) project. Stratospheric water vapour plays an important role in many key atmospheric processes and therefore an improved understanding of its daily variability is desirable. With the availability of high resolution, good quality Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) water vapour profiles, the ability of four different atmospheric models to assimilate these data is tested. MIPAS data have been assimilated over September 2003 into the models of the European Centre for Medium Range Weather Forecasts (ECMWF), the Belgian Institute for Space and Aeronomy (BIRA-IASB), the French Service d'Aéronomie (SA-IPSL) and the UK Met Office. The resultant middle atmosphere humidity analyses are compared against independent satellite data from the Halogen Occultation Experiment (HALOE), the Polar Ozone and Aerosol Measurement (POAM III) and the Stratospheric Aerosol and Gas Experiment (SAGE II). The MIPAS water vapour profiles are generally well assimilated in the ECMWF, BIRA-IASB and SA systems, producing stratosphere-mesosphere water vapour fields where the main features compare favourably with the independent observations. However, the models are less capable of assimilating the MIPAS data where water vapour values are locally extreme or in regions of strong humidity gradients, such as the southern hemisphere lower stratosphere polar vortex. Differences in the analyses can be attributed to the choice of humidity control variable, how the background error covariance matrix is generated, the model resolution and its complexity, the degree of quality control of the observations and the use of observations near the model boundaries. Due to the poor performance of the Met Office analyses the results are not included in the intercomparison

  8. Identification of irradiated foodstuffs: results of a European test intercomparison

    International Nuclear Information System (INIS)

    Raffi, J.; Belliardo, J.-J.; Agnel, J.-P.; Vincent, P.

    1993-01-01

    The results of an intercomparison, organized by the Community Bureau of Reference (Commission of the European Communities), on the use of Electron Spin Resonance spectroscopy for the identification of irradiated food are presented. A qualitative intercomparison was carried out using beef and trout bones, sardine scales, pistachio nut shells, dried grapes and papaya. Protocols are proposed for meat bones, fish bones (with some restrictions) and fruits such as dried grapes and papaya. The protocol for pistachio nuts and fruits such as strawberries is more complicated and further research is needed prior the organization of future intercomparisons. A quantitative intercomparison on poultry bones was also organized. Laboratories were able to distinguish between chicken bones irradiated at 1 to 3 kGy or 7 to 10 kGy. (author)

  9. Electron spin resonance intercomparison studies on irradiated foodstuffs

    International Nuclear Information System (INIS)

    Raffi, J.

    1992-01-01

    The results of intercomparison studies organized by the Community Bureau of Reference on the use of electron spin resonance spectroscopy for the identification of irradiated food are presented. A qualitative intercomparison was carried out using beef and trout bones, sardine scales, pistachio nut shells, dried grapes and papaya. A quantitative intercomparison involving the use of poultry bones was also organized. There was no difficulty in identifying meat bones, dried grapes and papaya. In the case of fish bones there is a need for further kinetic studies using different fish species. The identification of pistachio nut shells is more complicated and further research is needed prior to the organization of a further intercomparison. Laboratories were able to distinguish between chicken bones irradiated in the range 1 to 3 KGy or 7 to 10 KGy although there was a partial overlap between the results from different laboratories

  10. International NMR-based Environmental Metabolomics Intercomparison Exercise

    Science.gov (United States)

    Several fundamental requirements must be met so that NMR-based metabolomics and the related technique of metabonomics can be formally adopted into environmental monitoring and chemical risk assessment. Here we report an intercomparison exercise which has evaluated the effectivene...

  11. Electron spin resonance intercomparison studies on irradiated foodstuffs

    Energy Technology Data Exchange (ETDEWEB)

    Raffi, J [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (FR)

    1992-07-01

    The results of intercomparison studies organized by the Community Bureau of Reference on the use of electron spin resonance spectroscopy for the identification of irradiated food are presented. A qualitative intercomparison was carried out using beef and trout bones, sardine scales, pistachio nut shells, dried grapes and papaya. A quantitative intercomparison involving the use of poultry bones was also organized. There was no difficulty in identifying meat bones, dried grapes and papaya. In the case of fish bones there is a need for further kinetic studies using different fish species. The identification of pistachio nut shells is more complicated and further research is needed prior to the organization of a further intercomparison. Laboratories were able to distinguish between chicken bones irradiated in the range 1 to 3 KGy or 7 to 10 KGy although there was a partial overlap between the results from different laboratories.

  12. Intercomparison Measurements Exercises of Mobile Radiological Laboratories (invited paper)

    International Nuclear Information System (INIS)

    Martincic, R.

    2000-01-01

    After the reactor accident in Chernobyl, the importance of mobile radiological laboratories became evident and in situ gamma spectrometry became a common method for the rapid detection of gamma emitters in the environment. Since then different institutions in European countries have organised periodic intercomparison exercises of mobile radiological laboratories to improve the measurement methods and the preparedness of emergency monitoring teams. The general objectives of these workshops are to promote the knowledge and to exchange the experiences of emergency monitoring teams that use mobile radiological laboratories, as well as to foster the international harmonisation of emergency monitoring procedures and cooperation among teams. Finally, the results of intercomparison measurements have shown that such exercises are mandatory for rapid, efficient and correct environmental monitoring in nuclear or radiological emergencies. An overview of these intercomparison measurements is given, results from the 1999 intercomparison workshop are presented and lessons learned are discussed. (author)

  13. An international intercomparison of absorbed dose measurements for radiation therapy

    International Nuclear Information System (INIS)

    Taiman Kadni; Noriah Mod Ali

    2002-01-01

    Dose intercomparison on an international basis has become an important component of quality assurance measurement i.e. to check the performance of absorbed dose measurements in radiation therapy. The absorbed dose to water measurements for radiation therapy at the SSDL, MINT have been regularly compared through international intercomparison programmes organised by the IAEA Dosimetry Laboratory, Seibersdorf, Austria such as IAEA/WHO TLD postal dose quality audits and the Intercomparison of therapy level ionisation chamber calibration factors in terms of air kerma and absorbed dose to water calibration factors. The results of these intercomparison in terms of percentage deviations for Cobalt 60 gamma radiation and megavoltage x-ray from medical linear accelerators participated by the SSDL-MINT during the year 1985-2001 are within the acceptance limit. (Author)

  14. Performance of dichromate dosimetry systems in calibration and dose intercomparison

    International Nuclear Information System (INIS)

    Bof, E.S.; Smolko, E.

    1999-01-01

    This report presents the results of the High Dose Dosimetry Laboratory of Argentina during ten years of international intercomparisons for high dose with the International Dose Assurance Service (IDAS) of the IAEA, using the standard high dose dichromate dosimetry system, and the results of a high dose intercomparison regional exercise in which our Laboratory acted as a reference laboratory, using the standard high dose and low dose dichromate dosimetry system. (author)

  15. Intercomparison of radon gas detectors 1999 and 2000 at PSI

    International Nuclear Information System (INIS)

    Schuler, Christoph; Butterweck, Gernot

    2000-10-01

    This report describes the results of two radon intercomparison exercises performed by the Reference Laboratory for Radon Gas Activity Concentration Measurements at Paul Scherrer Institut from Sep 9th to Oct 6th, 1999, and from March 21st to 28th, 2000. Radon gas detectors and instruments were exposed in the PSI Radon Chamber in reference atmospheres to 1060 kBqhm -3 radon gas exposure at an average radon gas concentration of 6400 Bqm -3 and to 2050 kBqhm -3 radon gas exposure at an average radon gas concentration of 12500 Bqm -3 , respectively. These intercomparison exercises determined the performance of electret ionisation chambers, track etch detectors and measuring instruments at high humidity (1999 Intercomparison Exercise) and at a high radon gas exposure (2000 Intercomparison Exercise). In the 1999 Intercomparison Exercise, electret ionisation chambers revealed an influence on high humidity. This effect may be due to impurities on a microscopic scale on the electrets of these detectors. With few exceptions, in both the 1999 and the 2000 Radon Intercomparison Exercise the deviations of the measurement results to the reference radon gas concentration values were less than 15% (traceability criterion) and the standard deviation of the results of five detectors less than 15% (reproducibility criterion). (author) [de

  16. Comprehensive Australasian multicentre dosimetric intercomparison: issues, logistics and recommendations.

    Science.gov (United States)

    Ebert, M A; Harrison, K M; Cornes, D; Howlett, S J; Joseph, D J; Kron, T; Hamilton, C S; Denham, J W

    2009-02-01

    The present paper describes the logistics of the 2004-2008 Australasian Level III Dosimetry Intercomparison. Dosimetric intercomparisons (or 'audits') can be used in radiotherapy to evaluate the accuracy and quality of radiation delivery. An intercomparison was undertaken in New Zealand and Australia to evaluate the feasibility and logistics of ongoing dosimetric intercomparisons that evaluate all steps in the radiotherapy treatment process, known as a 'Level III' intercomparison. The study commenced in 2002 with the establishment of a study team, definition of the study protocol, acquisition of appropriate equipment and recruitment of participating radiotherapy centres. Measurements were undertaken between October 2004 and March 2008, and included collation of data on time, costs and logistics of the study. Forty independent Australian and New Zealand radiotherapy centres agreed to participate. Measurement visits were made to 37 of these centres. Data is presented on the costs of the study and the level of support required. The study involved the participation of 16 staff at the study centre who invested over 4000 hours in the study, and of over 200 professionals at participating centres. Recommendations are provided for future phantom-based intercomparisons. It is hoped that the present paper will be of benefit to any centres or groups contemplating similar activities by identifying the processes involved in establishing the study, the potential hazards and pitfalls, and expected resource requirements.

  17. First intercomparison exercise in the frame of the coordinated investigation program of the IAEA on regional intercomparison of personal dosimetry

    International Nuclear Information System (INIS)

    Massera, G.; Papadopulos, S.B.; Gregori, B.N.; DaSilva, T.; Griffith, R.; )

    1998-01-01

    During the days 7 and 11 of October of 1996 took place in Buenos Aires, Argentina, the first Meeting of the Coordinated Investigation program of the IAEA on Regional Intercomparison of Personal Dosimetry for Latin American. In this meeting participated nine representatives of reference laboratories and of personal dosimetry of the region. Fundamental aspect of personal dosimetry relates with the quantity personal dose equivalent Hp application and the implementation of intercomparison exercise in order to improve the quality of the dose estimation have been discussed. Also lectures carried out by the specialist on Hp and practical aspects of it implementation; answer and calibration according to the ISO 4037; intercomparison methods: procedures and organizations. It was carried out the first intercomparison exercise where the participants collaborated in the preparations and irradiations of personal dosemeters they have brought. (author)

  18. Reflecting on the challenges of building a rich interconnected metadata database to describe the experiments of phase six of the coupled climate model intercomparison project (CMIP6) for the Earth System Documentation Project (ES-DOC) and anticipating the opportunities that tooling and services based on rich metadata can provide.

    Science.gov (United States)

    Pascoe, C. L.

    2017-12-01

    The Coupled Model Intercomparison Project (CMIP) has coordinated climate model experiments involving multiple international modelling teams since 1995. This has led to a better understanding of past, present, and future climate. The 2017 sixth phase of the CMIP process (CMIP6) consists of a suite of common experiments, and 21 separate CMIP-Endorsed Model Intercomparison Projects (MIPs) making a total of 244 separate experiments. Precise descriptions of the suite of CMIP6 experiments have been captured in a Common Information Model (CIM) database by the Earth System Documentation Project (ES-DOC). The database contains descriptions of forcings, model configuration requirements, ensemble information and citation links, as well as text descriptions and information about the rationale for each experiment. The database was built from statements about the experiments found in the academic literature, the MIP submissions to the World Climate Research Programme (WCRP), WCRP summary tables and correspondence with the principle investigators for each MIP. The database was collated using spreadsheets which are archived in the ES-DOC Github repository and then rendered on the ES-DOC website. A diagramatic view of the workflow of building the database of experiment metadata for CMIP6 is shown in the attached figure.The CIM provides the formalism to collect detailed information from diverse sources in a standard way across all the CMIP6 MIPs. The ES-DOC documentation acts as a unified reference for CMIP6 information to be used both by data producers and consumers. This is especially important given the federated nature of the CMIP6 project. Because the CIM allows forcing constraints and other experiment attributes to be referred to by more than one experiment, we can streamline the process of collecting information from modelling groups about how they set up their models for each experiment. End users of the climate model archive will be able to ask questions enabled by the

  19. Intercomparison exercise on internal dose assessment. Final report of a joint IAEA-IDEAS project

    International Nuclear Information System (INIS)

    2007-09-01

    There have been several intercomparison exercises organized already at national and international levels for the assessment of occupational exposure due to intakes of radionuclides. These intercomparison exercises revealed significant differences in approaches, methods and assumptions, and consequently in the results. Because of the relevance of the issue for internal dosimetrists, the IAEA organized a new intercomparison exercise in cooperation with the IDEAS project General Guidelines for the Evaluation of Incorporation Monitoring Data, launched under the 5th EU Framework Programme (EU Contract No. FIKR-CT2001-00160). This new intercomparison exercise focused especially on the effect of the guidelines for harmonization of internal dosimetry. It also considered the following aspects: - to provide possibilities for the participating laboratories to check the quality of their internal dose assessment methods in applying the recent ICRP recommendations (e.g. for the new respiratory tract model); - to compare different approaches in interpretation of internal contamination monitoring data; - to quantify the differences in internal dose assessments based on the new guidelines or on other procedures, respectively; - to provide some figures for the influence of the input parameters on the monitoring results; and - to provide a broad forum for information exchange. Several cases have been selected for this exercise with the aim of covering a wide range of practices in the nuclear fuel cycle and in medical applications. The cases were: 1. Acute intake of HTO; 2. Acute inhalation of fission products 137 Cs and 90 Sr; 3. Intake of 60 Co; 4. Repeated intakes of 131 I; 5. Intake of enriched uranium; 6. Single intake of plutonium radionuclides and 241 Am. An Internet based approach had been used for the presentation of the cases, collection of responses and potential discussion of the results. Solutions to these cases were reported by 80 participants worldwide. This report

  20. INTERCOMPARISON OF RESULTS FOR A PWR ROD EJECTION ACCIDENT

    Energy Technology Data Exchange (ETDEWEB)

    DIAMOND,D.J.; ARONSON,A.; JO,J.; AVVAKUMOV,A.; MALOFEEV,V.; SIDOROV,V.; FERRARESI,P.; GOUIN,C.; ANIEL,S.; ROYER,M.E.

    1999-10-01

    This study is part of an overall program to understand the uncertainty in best-estimate calculations of the local fuel enthalpy during the rod ejection accident. Local fuel enthalpy is used as the acceptance criterion for this design-basis event and can also be used to estimate fuel damage for the purpose of determining radiological consequences. The study used results from neutron kinetics models in PARCS, BARS, and CRONOS2, codes developed in the US, the Russian Federation, and France, respectively. Since BARS uses a heterogeneous representation of the fuel assembly as opposed to the homogeneous representations in PARCS and CRONOS, the effect of the intercomparison was primarily to compare different intra-assembly models. Quantitative comparisons for core power, reactivity, assembly fuel enthalpy and pin power were carried out. In general the agreement between methods was very good providing additional confidence in the codes and providing a starting point for a quantitative assessment of the uncertainty in calculated fuel enthalpy using best-estimate methods.

  1. Intercomparison of Operational Ocean Forecasting Systems in the framework of GODAE

    Science.gov (United States)

    Hernandez, F.

    2009-04-01

    representation, either due to model and forcing fields errors, or assimilation scheme efficiency. Comparisons to sea-ice satellite products also evidence discrepancies linked to model, forcing and assimilation strategies of each forecasting system. Key words: Intercomparison, ocean analysis, operational oceanography, system assessment, metrics, validation GODAE Intercomparison Team: L. Bertino (NERSC/Norway), G. Brassington (BMRC/Australia), E. Chassignet (FSU/USA), J. Cummings (NRL/USA), F. Davidson (DFO/Canda), M. Drévillon (CERFACS/France), P. Hacker (IPRC/USA), M. Kamachi (MRI/Japan), J.-M. Lellouche (CERFACS/France), K. A. Lisæter (NERSC/Norway), R. Mahdon (UKMO/UK), M. Martin (UKMO/UK), A. Ratsimandresy (DFO/Canada), and C. Regnier (Mercator Ocean/France)

  2. Intercomparison of aerosol instruments: number concentration

    International Nuclear Information System (INIS)

    Knutson, E.O.; Sinclair, D.; Tu, K.W.; Hinchliffe, L.; Franklin, H.

    1982-05-01

    An intercomparison of aerosol instruments conducted February 23-27, 1981, at the Environmental Measurements Laboratory (EML) focused on five instruments: the Pollak and TSI condensation nucleus counters; the Active Scattering Aerosol Spectrometer (ASAS-X); and two aerosol electrometers. Test aerosols of sodium chloride and ammonium fluorescein generated by nebulization/electrostatic classification were used to obtain 195 lines of comparison data. Concentrations measured by the ASAS-X and the TSI aerosol electrometer averaged respectively 1.388 and 1.581 times that measured by the Pollak. These ratios were very stable during the week and there was little effect of particle size or material. Most other comparisons were equally stable. However, a review of past work at EML and elsewhere led to the disturbing conclusion that these ratios may change from year to year, or from season to season. A filter sample was taken from microscopy, concurrent with readings from the ASAS-X and the TSI condensation nucleus counters. In this sample, the two instruments differed by 20%. Within its 20% uncertainty, the filter result matched both the TSI and ASAS-X readings

  3. Intercomparisons of nine sky brightness detectors.

    Science.gov (United States)

    den Outer, Peter; Lolkema, Dorien; Haaima, Marty; van der Hoff, Rene; Spoelstra, Henk; Schmidt, Wim

    2011-01-01

    Nine Sky Quality Meters (SQMs) have been intercompared during a night time measurement campaign held in the Netherlands in April 2011. Since then the nine SQMs have been distributed across The Netherlands and form the Dutch network for monitoring night sky brightness. The goal of the intercomparison was to infer mutual calibration factors and obtain insight into the variability of the SQMs under different meteorological situations. An ensemble average is built from the individual measurements and used as a reference to infer the mutual calibration factors. Data required additional synchronization prior to the calibration determination, because the effect of moving clouds combined with small misalignments emerges as time jitter in the measurements. Initial scatter of the individual instruments lies between ±14%. Individual night time sums range from -16% to +20%. Intercalibration reduces this to 0.5%, and -7% to +9%, respectively. During the campaign the smallest luminance measured was 0.657 ± 0.003 mcd/m(2) on 12 April, and the largest value was 5.94 ± 0.03 mcd/m(2) on 2 April. During both occurrences interfering circumstances like snow cover or moonlight were absent.

  4. Aircraft to aircraft intercomparison during SEMAPHORE

    Science.gov (United States)

    Lambert, Dominique; Durand, Pierre

    1998-10-01

    During the Structure des Echanges Mer-Atmosphère, Propriétés des Hétérogénéités Océaniques: Recherche Expérimentale (SEMAPHORE) experiment, performed in the Azores region in 1993, two French research aircraft were simultaneously used for in situ measurements in the atmospheric boundary layer. We present the results obtained from one intercomparison flight between the two aircraft. The mean parameters generally agree well, although the temperature has to be slightly shifted in order to be in agreement for the two aircraft. A detailed comparison of the turbulence parameters revealed no bias. The agreement is good for variances and is satisfactory for fluxes and skewness. A thorough study of the errors involved in flux computation revealed that the greatest accuracy is obtained for latent heat flux. Errors in sensible heat flux are considerably greater, and the worst results are obtained for momentum flux. The latter parameter, however, is more accurate than expected from previous parameterizations.

  5. Intercomparison for individual monitoring. Vol. 1

    International Nuclear Information System (INIS)

    1991-10-01

    Twenty-one laboratories from 19 countries participated in the Intercomparison. The exposures were conducted in May and June of 1988, and the dosimeters were returned to the participating laboratories for processing. The results were returned to the IAEA in late 1988. They were reviewed and compiled at the end of the year. The technical background for the CRP is described in the papers appearing in Parts 1 and 2 of this report. The results are summarized in Parts 3 and 4. An important aspect of the programme was comparison of the techniques used to evaluate the participants' dosimeters (Part 5). There are a number of technical and philosophical issues related to implementation of the ICRU operational quantities, particularly as they relate to needs of Agency Member States (Part 6). Various aspects of the dosimetry system affect the accuracy and precision of the overall results (Part 7). The report concludes with a Summary and Conclusions in Part 8, and a complete list of the participants is shown in Part 9. (orig./DG)

  6. Argentine Republic intercomparison programme for personal dosimeters

    International Nuclear Information System (INIS)

    Gregori, Beatriz N.; Papadopulos, Susana B.; Kunst, Juan J.; Cruzate, Juan A.; Saravi, Margarita C.

    2004-01-01

    In 1997 an Intercomparison Program for individual monitoring started in order to test (on a voluntary basis) the performance in absorbed dose and personal dose equivalent determinations. The aim of the program was also to gain some insight into the general aspects related to the type of the personnel dosimeter used, the calibration procedures, the phantom spectral dependence and the management of radiological quantities. The Regional Reference Center for Dosimetry (CCR), of the Argentine National Atomic Energy Commission and the Physical Dosimetry Laboratory of the Argentine National Regulatory Authority, performed the irradiations. Those were done free air and on ICRU phantom, using X-ray, quality ISO: W60, W80, W110 and W200; and 137 Cs and 60 Co gamma rays, normal and angular (0, 30, 60 degrees) incidence. In the framework of the Program, an upgraded workshop took place and the national standard, IRAM 17146, was elaborated as well. In this work, the laboratories performance and its temporal evolution is shown from 1997 up to 2002. The suggestions to improve their performance are also included. (author)

  7. Intercomparison between ICRP60 and ICRP103

    International Nuclear Information System (INIS)

    Mahdy, M. T. A.

    2014-04-01

    In this project inter-comparison between the recommendations from ICRP publication 60, 1900 and the recommendations from ICRP publication 103, 2007 is made. The present 2007 recommendations is an update based on the latest available scientific information of the biology and physics of radiation exposure .This comparison covers the Exposure situations, Tissue Weighting Factors wT, Radiation Weighting Factors wR, and the three Fundamental Principles of Radiological Protection and the protection of the environment. ICRP has retained its fundamental hypothesis for the induction of stochastic effects of linearity of dose and effect without threshold and a dose and dose-rate effectiveness factor (DDREF) of 2 to derive nominal risk coefficients for low doses and low dose rates. While the overall detriment from low radiation doses has remained unchanged, ICRP has made adjustments to the values of the radiation and tissue weighting factors. In particular, the tissue weighting factor for breast has increased while that for gonads has decreased. There are some presentational changes to the system of protection. While ICRP has maintained the three fundamental principles-justification, optimization of protection, and dose limitation-it has attempted to develop a more holistic approach to radiological protection covering all exposure situations-planned, existing and emergency and all radiation sources, whether of natural or artificial origin. Dose constraints and reference levels are categorized into three bands which should assist in rationalizing the many values of dose restrictions given in earlier ICRP publications. (au)

  8. The IAEA intercomparison for individual monitoring

    International Nuclear Information System (INIS)

    Griffith, R.V.; Boehm, J.; Herrman, D.; Strachotinsky, C.; Thompson, I.M.G.

    1990-01-01

    In 1985 the International Commission on Radiation Units and Measurements introduced a new set of operational quantities for radiation protection purposes through Report 39. The International Atomic Energy Agency has been concerned with the impact of possible adoption of these quantities by its 113 Member States. Thus the Agency implemented a Coordinated Research Programme on Intercomparison for Individual Monitoring in 1987. The first phase completed with a Research Coordination meeting of the participants in April, 1989. Photon exposures were provided at 11 energies over a range from 18 keV to 1.25 MeV at three standards laboratories in Austria, the GDR and the UK. Technical coordination was provided by the PTB, Braunschweig. Twenty one laboratories from 19 countries participated with film, TLD of various types, and combination dosemeters. Irradiations were performed on the IAEA 30 cm cubic, water-filled phantom that is in use throughout its network of 61 Secondary Standard Dosimetry Laboratories. Conversion coefficients for the IAEA phantom were calculated by the PTB and confirmed through measurements at ASMW in the GDR. Preliminary results indicated that the type of dosemeter (film or TLD) had little effect on the quality of results. The most important factor appears to be the specific techniques used for data interpretation. (author)

  9. Intercomparisons of Nine Sky Brightness Detectors

    Directory of Open Access Journals (Sweden)

    Henk Spoelstra

    2011-10-01

    Full Text Available Nine Sky Quality Meters (SQMs have been intercompared during a night time measurement campaign held in the Netherlands in April 2011. Since then the nine SQMs have been distributed across the Netherlands and form the Dutch network for monitoring night sky brightness. The goal of the intercomparison was to infer mutual calibration factors and obtain insight into the variability of the SQMs under different meteorological situations. An ensemble average is built from the individual measurements and used as a reference to infer the mutual calibration factors. Data required additional synchronization prior to the calibration determination, because the effect of moving clouds combined with small misalignments emerges as time jitter in the measurements. Initial scatter of the individual instruments lies between ±14%. Individual night time sums range from −16% to +20%. Intercalibration reduces this to 0.5%, and −7% to +9%, respectively. During the campaign the smallest luminance measured was 0.657 ± 0.003 mcd/m2 on 12 April, and the largest value was 5.94 ± 0.03 mcd/m2 on 2 April. During both occurrences interfering circumstances like snow cover or moonlight were absent.

  10. Fennec dust forecast intercomparison over the Sahara in June 2011

    Directory of Open Access Journals (Sweden)

    J.-P. Chaboureau

    2016-06-01

    Full Text Available In the framework of the Fennec international programme, a field campaign was conducted in June 2011 over the western Sahara. It led to the first observational data set ever obtained that documents the dynamics, thermodynamics and composition of the Saharan atmospheric boundary layer (SABL under the influence of the heat low. In support to the aircraft operation, four dust forecasts were run daily at low and high resolutions with convection-parameterizing and convection-permitting models, respectively. The unique airborne and ground-based data sets allowed the first ever intercomparison of dust forecasts over the western Sahara. At monthly scale, large aerosol optical depths (AODs were forecast over the Sahara, a feature observed by satellite retrievals but with different magnitudes. The AOD intensity was correctly predicted by the high-resolution models, while it was underestimated by the low-resolution models. This was partly because of the generation of strong near-surface wind associated with thunderstorm-related density currents that could only be reproduced by models representing convection explicitly. Such models yield emissions mainly in the afternoon that dominate the total emission over the western fringes of the Adrar des Iforas and the Aïr Mountains in the high-resolution forecasts. Over the western Sahara, where the harmattan contributes up to 80 % of dust emission, all the models were successful in forecasting the deep well-mixed SABL. Some of them, however, missed the large near-surface dust concentration generated by density currents and low-level winds. This feature, observed repeatedly by the airborne lidar, was partly forecast by one high-resolution model only.

  11. EURADOS intercomparison 2006 to harmonise European early warning dosimetry systems

    International Nuclear Information System (INIS)

    Dombrowski, H.; Neumaier, S.; Thompson, I. M. G.; Wissmann, F.

    2009-01-01

    In 2006, the European Radiation Dosimetry (EURADOS) Working Group on Environmental Radiation Monitoring (WG3) organised a third European intercomparison of dosimetry systems operated in national early warning networks. Similar to the intercomparisons in 1999 and 2002, the main aim of this exercise was to support the process of harmonisation of area monitoring in Europe by providing the network operators with basic information on the calibration and performance of their dosimetry systems. In order to characterise these systems, their following basic parameters were investigated: the response to terrestrial and cosmic radiation, the detectors' inherent background, the response at low dose rates, the energy dependence of the response as well as the sensitivity of the detector systems to small changes of the dose rate in a natural environmental radiation field. In the 2006 EURADOS intercomparison, scientists from seven countries participated to study the characteristics of 11 detector systems. All results are presented in terms of the operational quantity ambient dose equivalent, H * (10). The advent of this quantity has caused the development of new detector systems for area monitoring. Some of these new systems participated in a EURADOS intercomparison for the first time. The results are consistently presented together with uncertainties so that statistical effects can be distinguished from real detector features, which improves the interpretation of the results. By using the results of this intercomparison, some detectors were re-calibrated. The achievable improvements concerning harmonisation in dose-rate measurements in the natural environment are discussed. (authors)

  12. Intercomparison of JAERI Torso Phantom lung sets

    International Nuclear Information System (INIS)

    Kramer, Gary H.; Hauck, Barry M.

    2000-01-01

    During the course of an IAEA sponsored In Vivo intercomparison using the JAERI phantom the Human Monitoring Laboratory was able to intercompare thirteen lung sets made by three suppliers. One set consisted of sliced lungs with planar inserts containing different radionuclides. The others consisted of whole lung sets with the activity homogeneously distributed throughout the tissue substitute material. Radionuclides in the study were: natural uranium, 3% enriched uranium, 241 Am, 238 Pu, 239 Pu, 152 Eu, and 232 Th Except for the 241 Am (59.5 keV) and occasionally one of the 232 Th (209 keV) photopeaks, the lung sets that had radioactivity homogeneously distributed throughout the tissue equivalent lung tissue material showed good agreement. The 241 Am lung set gave a counting efficiency that appeared 25% too high for all overlay plate configurations. This was observed by other participants. It exemplifies that the manufacture of tissue substitute lung sets is still something of a black art. Despite all precautions, this lung set is either inhomogeneous or has had the wrong activity added. Heterogeneity can lead to an error in the activity estimate of a factor of three if the activity was severely localised due to improper mixing. A factor of 1.25, which appears to be the discrepancy, could easily be explained in this way. It will not be known for some time, however, what the true reason is as the participants are still waiting for the destructive analysis of this lung set to determine the 'true' activity. The sliced lungs ( 241 Am, 152 Eu, and U-nat) manufactured by the Human Monitoring Laboratory are in excellent agreement with the other lung sets. The advantages of sliced lung sets and planar sources are manifold. Activity can be distributed in a known and reproducible manner to mimic either a homogeneous or heterogeneous distribution in the lung. Short lived radionuclides can be used. Cost is much less than purchasing or manufacturing lung sets that have the

  13. Argentine intercomparison programme for personal dosimetry

    International Nuclear Information System (INIS)

    Gregori, B.N.; Papadopulos, S.B.; Cruzate, J.; Kunst, J.J.; Saravi, M.

    2005-01-01

    Full text: In 1997 began in Argentine, sponsored by Nuclear Regulatory Authority (ARN) the intercomparison program for personal dosimetry laboratories, on a voluntary basis. Up to know 6 exercises have been done. The program began with a workshop to present the quantities, personal dose equivalent, Hp(10) and extremities dose equivalent, Hs(d). The first aim of this program was to know the true sate of personal dosimetry laboratories in the country, and then introduce the personal dose equivalent, Hp(10) into the dose measurements. The Regional Reference Center for Dosimetry (CCR), belonging to CNEA and the Physical Dosimetry Laboratory of ARN performed the irradiation. Those were done air free and on ICRU phantom, using x-ray, quality ISO: W60, W110 and W200; and 137 Cs and 60 Co gamma rays. The irradiation was made following ISO 4037 (2) recommendations. There are studied the dose, energy and angular response of the different measuring system. The range of the dose analyzed was from 0.2 mSv up to 80 mSv. The beam incidence was normal and also 20 o and 60 o . The dosimeters irradiation's were performed kerma in free in air and in phantom in order to study the availability of the service to evaluate the behavior as a function of kerma free in air or Hp(10). At the same time several items have been asked to each participant referring to the action range, the detectors characteristics, the laboratory procedures, the existence of an algorithm and its use for the dosimeter evaluation and the wish to participate in a quality assurance program. The program worked in writing a standard of personal dosimetry laboratories, that was published in 2001. In this work the results of each laboratory and its performance based on the ICRP-60 and ICRP-35 acceptance criteria are shown. Also the laboratory evolution and inquiry analyses have been included. (author)

  14. Tenth ORNL Personnel Dosimetry Intercomparison Study

    International Nuclear Information System (INIS)

    Swaja, R.E.; Chou, T.L.; Sims, C.S.; Greene, R.T.

    1985-03-01

    The Tenth Personnel Dosimetry Intercomparison Study was conducted at the Oak Ridge National Laboratory during April 9-11, 1984. Dosemeter badges from 31 participating organizations were mounted on 40cm Lucite phantoms and exposed to a range of dose equivalents which could be encountered during routine personnel monitoring in mixed radiation fields. The Health Physics Research Reactor served as the only source of radiation for eight of the ten irradiations which included a low (approx. 0.50 mSv) and high (approx. 10.00 mSv) neutron dose equivalent run for each of four shield conditions. Two irradiations were also conducted for which concrete- and Lucite-shield reactor irradiations were gamma-enhanced using a 137 Cs source. Results indicated that some participants had difficulty obtaining measurable indication of neutron and gamma exposures at dose equivalents less than about 0.50 mSv and 0.20 mSv, respectively. Albedo dosemeters provided the best overall accuracy and precision for the neutron measurements. Direct interaction TLD systems showed significant variation in accuracy with incident spectrum, and threshold neutron dosemeters (film and recoil track) underestimated reference values by more than 50%. Gamma dose equivalents estimated in the mixed fields were higher than reference values with TL gamma dosemeters generally yielding more accurate results than film. Under the conditions of this study in which participants had information concerning exposure conditions and radiation field characteristics prior to dosemeter evaluation, only slightly more than half of all reported results met regulatory standards for neutron and gamma accuracy. 19 refs., 2 figs., 29 tabs

  15. AQCS 1990. Intercomparison runs, reference materials

    International Nuclear Information System (INIS)

    1990-01-01

    The purpose of the Analytical Quality Control Services (AQCS) programme provided by the International Atomic Energy Agency (Agency) is to assist laboratories engaged in the analysis of nuclear, environmental, biological, and materials of marine origin for radionuclide, major, minor and trace elements, as well as stable isotopes using atomic and nuclear analytical techniques, to check the quality of their work. Such a control is necessary since results of analytical activities may be the basis upon which economic, administrative, medical or legal decisions are taken; they must, therefore, be documented to be sufficiently reliable. The Agency has instituted the AQCS-programme which for 1990 will involve distributing samples for Intercomparison Runs and Reference Materials in a way similar to that of previous years. The Agency's Analytical Quality Control Services (AQCS) programme provides mainly three types of materials: materials which can be used in analytical laboratories working in the fields of nuclear technology and isotope hydrology. These include uranium ore Reference Materials and other substances of interest for nuclear fuel technology as well as stable isotope Reference Materials for mass spectrometric determination of isotope ratios in natural waters; materials with known content of uranium, thorium and/or transuranium elements or fission products for the determination of environmental radioactivity or control of nuclear safety; materials for use in the determination of stable trace elements in environmental, biomedical and marine research. Radiochemical methods such as neutron activation or isotope dilution analysis are often used in the determination of such trace elements and constitute an important contribution of nuclear techniques to applied science. Tabs

  16. Reference values and evaluation of the results of intercomparisons

    International Nuclear Information System (INIS)

    Aigner, H.; Deron, S.; Kuhn, E.

    1981-01-01

    The need of a reference value for the composition of materials distributed in intercomparisons is generally recognized. A single reference laboratory or a group of reference laboratories may be used to establish this reference value. The respective advantages and limitations of the two approaches are discussed. The reference measurements must be evaluated to provide the confidence limits of the reference value but also an estimate of the possible heterogeneity of the materials and its samples. The results of the intercomparison measurements should themselves be evaluated to test and discuss the significance of the biases of individual and selected groups of laboratories or techniques. The approach taken by the Analytical Quality Control Services of the International Atomic Energy Agency is illustrated by the SR-1 intercomparison on uranium assay in UO 2 powder

  17. Intercomparison of different operational oceanographic forecast products in the CMEMS IBI area

    Science.gov (United States)

    Lorente, Pablo; Sotillo, Marcos G.; Dabrowski, Tomasz; Amo-Baladrón, Arancha; Aznar, Roland; De Pascual, Alvaro; Levier, Bruno; Bowyer, Peter; Cossarini, Gianpiero; Salon, Stefano; Tonani, Marina; Alvarez-Fanjul, Enrique

    2017-04-01

    The development of skill assessment software packages and dedicated web applications is a relatively novel theme in operational oceanography. Within the CMEMS IBI-MFC, the quality of IBI (Iberia-Biscay-Ireland) forecast products is assessed by means of NARVAL (North Atlantic Regional VALidation) web-based tool. The validation of IBI against independent in situ and remote-sensing measurements is routinely conducted to evaluate model's veracity and prognostic capabilities. Noticeable efforts are in progress to define meaningful skill scores and statistical metrics to quantitatively assess the quality and reliability of the IBI model solution. Likewise, the IBI-MFC compares the IBI forecast products with other model solutions by setting up specific intercomparison exercises on overlapping areas at diverse timescales. In this context, NARVAL web tool already includes a specific module to evaluate strengths and weaknesses of IBI versus other CMEMS operational ocean forecasting systems (OOFSs). In particular, the IBI physical ocean solution is compared against the CMEMS MED and NWS OOFSs. These CMEMS regional services delivered for the Mediterranean and the North West Shelves include data assimilation schemes in their respective operational chains and generate analogous ocean forecast products to the IBI ones. A number of physical parameters (i.e. sea surface temperature, salinity and current velocities) are evaluated through NARVAL on a daily basis in the overlapping areas existing between these three regional systems. NARVAL is currently being updated in order to extend this intercomparison of ocean model parameters to the biogeochemical solutions provided by the aforementioned OOFSs. More specifically, the simulated chlorophyll concentration is evaluated over several subregions of particular concern by using as benchmark the CMEMS satellite-derived observational products. In addition to this IBI comparison against other regional CMEMS products on overlapping areas, a

  18. Optimal interpolation method for intercomparison of atmospheric measurements.

    Science.gov (United States)

    Ridolfi, Marco; Ceccherini, Simone; Carli, Bruno

    2006-04-01

    Intercomparison of atmospheric measurements is often a difficult task because of the different spatial response functions of the experiments considered. We propose a new method for comparison of two atmospheric profiles characterized by averaging kernels with different vertical resolutions. The method minimizes the smoothing error induced by the differences in the averaging kernels by exploiting an optimal interpolation rule to map one profile into the retrieval grid of the other. Compared with the techniques published so far, this method permits one to retain the vertical resolution of the less-resolved profile involved in the intercomparison.

  19. Analysis of laboratory intercomparison data: a matter of independence

    Directory of Open Access Journals (Sweden)

    Mauro F. Rebelo

    2003-05-01

    Full Text Available When laboratory intercomparison exercises are conducted, there is no a priori dependence of the concentration of a certain compound determined in one laboratory to that determined by another(s. The same applies when comparing different methodologies. A existing data set of total mercury readings in fish muscle samples involved in a Brazilian intercomparison exercise was used to show that correlation analysis is the most effective statistical tool in this kind of experiments. Problems associated with alternative analytical tools such as mean or paired 't'-test comparison and regression analysis are discussed.

  20. Environmental radioactive intercomparison program and radioactive standards program

    Energy Technology Data Exchange (ETDEWEB)

    Dilbeck, G. [Environmental Monitoring Systems Laboratory, Las Vegas, NV (United States)

    1993-12-31

    The Environmental Radioactivity Intercomparison Program described herein provides quality assurance support for laboratories involved in analyzing public drinking water under the Safe Drinking Water Act (SDWA) Regulations, and to the environmental radiation monitoring activities of various agencies. More than 300 federal and state nuclear facilities and private laboratories participate in some phase of the program. This presentation describes the Intercomparison Program studies and matrices involved, summarizes the precision and accuracy requirements of various radioactive analytes, and describes the traceability determinations involved with radioactive calibration standards distributed to the participants. A summary of program participants, sample and report distributions, and additional responsibilities of this program are discussed.

  1. International intercomparison of neutron spectra evaluating methods using activation detectors

    International Nuclear Information System (INIS)

    Fischer, A.

    1975-06-01

    The international intercomparison of neutron spectrum evaluation methods using activation detectors was organized by the IAEA in 1971 - 1972. All of the contributions and the results of a critical evaluation are presented here. The spectra of different contributors are compared to a reference spectrum by means of different integrals and weighting functions. Different cross section sets, foil numbers, energy point systems, guess spectra used by the contributors cause differences in the resulting spectra. The possible ways of separating these effects are also investigated. Suggestions are made for the organization of a new intercomparison on the basis of more uniform input data. (orig.) [de

  2. Comparing apples and oranges: the Community Intercomparison Suite

    Science.gov (United States)

    Schutgens, Nick; Stier, Philip; Kershaw, Philip; Pascoe, Stephen

    2015-04-01

    Visual representation and comparison of geoscientific datasets presents a huge challenge due to the large variety of file formats and spatio-temporal sampling of data (be they observations or simulations). The Community Intercomparison Suite attempts to greatly simplify these tasks for users by offering an intelligent but simple command line tool for visualisation and colocation of diverse datasets. In addition, CIS can subset and aggregate large datasets into smaller more manageable datasets. Our philosophy is to remove as much as possible the need for specialist knowledge by the user of the structure of a dataset. The colocation of observations with model data is as simple as: "cis col ::" which will resample the simulation data to the spatio-temporal sampling of the observations, contingent on a few user-defined options that specify a resampling kernel. As an example, we apply CIS to a case study of biomass burning aerosol from the Congo. Remote sensing observations, in-situe observations and model data are shown in various plots, with the purpose of either comparing different datasets or integrating them into a single comprehensive picture. CIS can deal with both gridded and ungridded datasets of 2, 3 or 4 spatio-temporal dimensions. It can handle different spatial coordinates (e.g. longitude or distance, altitude or pressure level). CIS supports both HDF, netCDF and ASCII file formats. The suite is written in Python with entirely publicly available open source dependencies. Plug-ins allow a high degree of user-moddability. A web-based developer hub includes a manual and simple examples. CIS is developed as open source code by a specialist IT company under supervision of scientists from the University of Oxford and the Centre of Environmental Data Archival as part of investment in the JASMIN superdatacluster facility.

  3. Design of the MISMIP+, ISOMIP+, and MISOMIP ice-sheet, ocean, and coupled ice sheet-ocean intercomparison projects

    Science.gov (United States)

    Asay-Davis, Xylar; Cornford, Stephen; Martin, Daniel; Gudmundsson, Hilmar; Holland, David; Holland, Denise

    2015-04-01

    The MISMIP and MISMIP3D marine ice sheet model intercomparison exercises have become popular benchmarks, and several modeling groups have used them to show how their models compare to both analytical results and other models. Similarly, the ISOMIP (Ice Shelf-Ocean Model Intercomparison Project) experiments have acted as a proving ground for ocean models with sub-ice-shelf cavities.As coupled ice sheet-ocean models become available, an updated set of benchmark experiments is needed. To this end, we propose sequel experiments, MISMIP+ and ISOMIP+, with an end goal of coupling the two in a third intercomparison exercise, MISOMIP (the Marine Ice Sheet-Ocean Model Intercomparison Project). Like MISMIP3D, the MISMIP+ experiments take place in an idealized, three-dimensional setting and compare full 3D (Stokes) and reduced, hydrostatic models. Unlike the earlier exercises, the primary focus will be the response of models to sub-shelf melting. The chosen configuration features an ice shelf that experiences substantial lateral shear and buttresses the upstream ice, and so is well suited to melting experiments. Differences between the steady states of each model are minor compared to the response to melt-rate perturbations, reflecting typical real-world applications where parameters are chosen so that the initial states of all models tend to match observations. The three ISOMIP+ experiments have been designed to to make use of the same bedrock topography as MISMIP+ and using ice-shelf geometries from MISMIP+ results produced by the BISICLES ice-sheet model. The first two experiments use static ice-shelf geometries to simulate the evolution of ocean dynamics and resulting melt rates to a quasi-steady state when far-field forcing changes in either from cold to warm or from warm to cold states. The third experiment prescribes 200 years of dynamic ice-shelf geometry (with both retreating and advancing ice) based on a BISICLES simulation along with similar flips between warm and

  4. Results of the regional intercomparison on internal dosimetry – 2013: Interpretation of monitoring data for effective dose assessment due to internal exposure

    International Nuclear Information System (INIS)

    Rojo, A.M.; Puerta, N.; Gossio, S.; Gómez Parada, I.

    2015-01-01

    Internal dosimetry intercomparisons are essential for the verification of the models applied and the results consistency. To that aim, the 1. Regional Intercomparison Exercise was organized in 2005 in the frame of the RLA 9/049. The results of this exercise led to the 2. Regional Intercomparison Exercise in 2013, which was organized in the frame of the RLA 9/066 and coordinated by Autoridad Regulatoria Nuclear (ARN) of Argentina. Four simulated cases covering intakes of “1”3”1I, “1”3”7Cs and Tritium were proposed. The exercise counted with the participation of 19 centres from 13 countries. This report shows a complete analysis of the participant’s results in this 2nd. exercise, useful to test their skills and acquired knowledge, particularly in applying the IDEAS guidelines. It is important to highlight the improvement in the general performance of the participants. (authors) [es

  5. Safety assessment of near surface radioactive waste disposal facilities: Model intercomparison using simple hypothetical data (Test Case 1). First report of NSARS. Part of the co-ordinated research programme on the safety assessment of near surface radioactive waste disposal facilities (NSARS)

    International Nuclear Information System (INIS)

    1995-11-01

    In many countries near surface disposal is the preferred option for the comparatively large volumes of low and intermediate level wastes which arise during nuclear power plant operations, nuclear fuel reprocessing and also for the wastes arising from radionuclide applications in hospitals and research establishments. Near surface disposal is also widely practised in the case of hazardous wastes from chemical industries. It is obviously necessary to show that waste disposal methods are safe and that both man and the environment will be adequately protected. Following a previous related Co-ordinated Research Programme (CRP) on ''Migration and Biological Transfer of Radionuclides from Shallow Land Burial'' during 1985 to 1989 (IAEA-TECDOC-579, Vienna, 1990), the issue of reliability of safety assessments was identified as an important topic for further support and development. A new CRP was formulated with the acronym NSARS (Near Surface Radioactive Waste Disposal Safety Assessment Reliability Study). This technical document is the first report of from the CRP and contains the intercomparison of results of the first test exercise (Test Case 1) on modelling of potential radiation exposures as a result of near surface disposal. Test Case 1 is based on entirely hypothetical data and includes consideration of exposures due to leaching and as a result of human intrusion into the site. Refs, figs and tabs

  6. Safety assessment of near surface radioactive waste disposal facilities: Model intercomparison using simple hypothetical data (Test Case 1). First report of NSARS. Part of the co-ordinated research programme on the safety assessment of near surface radioactive waste disposal facilities (NSARS)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    In many countries near surface disposal is the preferred option for the comparatively large volumes of low and intermediate level wastes which arise during nuclear power plant operations, nuclear fuel reprocessing and also for the wastes arising from radionuclide applications in hospitals and research establishments. Near surface disposal is also widely practised in the case of hazardous wastes from chemical industries. It is obviously necessary to show that waste disposal methods are safe and that both man and the environment will be adequately protected. Following a previous related Co-ordinated Research Programme (CRP) on ``Migration and Biological Transfer of Radionuclides from Shallow Land Burial`` during 1985 to 1989 (IAEA-TECDOC-579, Vienna, 1990), the issue of reliability of safety assessments was identified as an important topic for further support and development. A new CRP was formulated with the acronym NSARS (Near Surface Radioactive Waste Disposal Safety Assessment Reliability Study). This technical document is the first report of from the CRP and contains the intercomparison of results of the first test exercise (Test Case 1) on modelling of potential radiation exposures as a result of near surface disposal. Test Case 1 is based on entirely hypothetical data and includes consideration of exposures due to leaching and as a result of human intrusion into the site. Refs, figs and tabs.

  7. The program of international intercomparison of accident dosimetry

    International Nuclear Information System (INIS)

    2002-06-01

    The French institute of radioprotection and nuclear safety (IRSN) has carried out in June 2002 an international intercomparison program for the testing of the physical and biological accident dosimetry techniques. The intercomparison is jointly organized by the IRSN and the OECD-NEA with the sustain of the European commission and the collaboration of the CEA centre of Valduc (France). About 30 countries have participated to this program. Each country has supplied its own dosimeters and biological samples which have been irradiated using the Silene reactor of CEA-Valduc or a 60 Co source. These experiments allow to test the new dosimetric techniques that have been developed since the previous intercomparison program (1993) and to confirm or improve the performances of older techniques. Aside from the intercomparison exercise, this report makes a status of the known radiological accidents and of the effects of high doses of ionizing radiations on human health (symptoms, therapeutics). It explains the phenomenology of criticality accidents, the prevention means, and the history of such accidents up to the Tokai-Mura one in 1999. Finally, the dosimetry of criticality is presented with its physical and biological techniques. (J.S.)

  8. Intercomparison of IAEA airborne particulate matter reference material. Appendix 19

    International Nuclear Information System (INIS)

    Landsberger, Sheldon; Wu, De; Vermette, Stephen; Cizek, William

    1995-01-01

    Fifty air filters with fine and coarse fractions were prepared from NIST 2710 contaminated soil. Eighteen pairs were made and sent to seventeen laboratories of the CRP program on Applied Research on Air Pollution Using Nuclear-Related Analytical Techniques for elemental determination. The results of this intercomparison are discussed in this paper. (author)

  9. Intercomparison of low-level tritium in water

    International Nuclear Information System (INIS)

    Sipka, V.; Zupancic, M.; Hadzisehovic, M.; Bacic, S.; Vukovic, Z.

    1989-01-01

    In 1985 the Section of Isotope Hydrology of the IAEA organized the fourth intercomparison for low-level tritium counting in waters. Four water samples with different 3 H concentration were sent to 85 laboratories willing to participate. The results from the different laboratories were presented in the unified questionnaires and coded. The participation in the intercomparisons for every laboratory doing low-level 3 H measurements in the waters is very important and useful. This is a best way to check the entire procedure and methods of the measurements and the reliability of the standards used. Since our laboratories are doing the natural 3 H concentration measurement in the waters for the environmental control and hydrology reasons it was necessary to take part in this intercomparison. Our standard procedure was applied. The 3 H activity in the samples was measured by liquid scintillation counting after an electrolytic enrichment. The results of our measurements of the four water samples, received from the organizers, are presented on the figures and tables presenting summary of the intercomparison. It is clear that our measurement (procedure and standards) have given satisfactory results (author)

  10. Intercomparison program of personal dosemeters in the Argentine Republic

    International Nuclear Information System (INIS)

    Gregori, B.N.; Papadopulos, S.B.; Kunst, J.J.

    1998-01-01

    During 1997, under the auspices of the Nuclear Regulatory Authority (ARN), its was held the third exercise of intercomparison of laboratories of personal dosimetry. The dosemeters were irradiated in X-ray beams ISO quality W60, W110, W200 and gamma sources cesium 137 and cobalt 60. The irradiation were performed kerma free in air and in phantom in order to study the capacity to evaluate both conditions. An extent range of doses (low-high) have been given 0.3 mSv- 20mSv in order to determine the operative performance o each laboratory. Over 19 laboratories of Argentina, participated 13 (65%) and finished the intercomparison 12 (60%) of them. The systems of dosimetry detection were based on film and TLD. During this intercomparison as inquiry about several items related with the laboratories have been made. In this work are shown the individual laboratory results of the intercomparison related with the acceptance curve criteria ICRP 60 and 55. (author)

  11. PNNL Results from 2010 CALIBAN Criticality Accident Dosimeter Intercomparison Exercise

    International Nuclear Information System (INIS)

    Hill, Robin L.; Conrady, Matthew M.

    2011-01-01

    This document reports the results of the Hanford personnel nuclear accident dosimeter (PNAD) and fixed nuclear accident dosimeter (FNAD) during a criticality accident dosimeter intercomparison exercise at the CEA Valduc Center on September 20-23, 2010. Pacific Northwest National Laboratory (PNNL) participated in a criticality accident dosimeter intercomparison exercise at the Commissariat a Energie Atomique (CEA) Valduc Center near Dijon, France on September 20-23, 2010. The intercomparison exercise was funded by the U.S. Department of Energy, Nuclear Criticality Safety Program, with Lawrence Livermore National Laboratory as the lead Laboratory. PNNL was one of six invited DOE Laboratory participants. The other participating Laboratories were: Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 National Security Complex at Oak Ridge, and Sandia National Laboratory (SNL). The goals of PNNL's participation in the intercomparison exercise were to test and validate the procedures and algorithm currently used for the Hanford personnel nuclear accident dosimeters (PNADs) on the metallic reactor, CALIBAN, to test exposures to PNADs from the side and from behind a phantom, and to test PNADs that were taken from a historical batch of Hanford PNADs that had varying degrees of degradation of the bare indium foil. Similar testing of the PNADs was done on the Valduc SILENE test reactor in 2009 (Hill and Conrady, 2010). The CALIBAN results are reported here.

  12. RCA/IAEA third external dosimetry intercomparison in East Asia

    International Nuclear Information System (INIS)

    Momose, T.; Yamamoto, H.; Cruz Suarez, R.

    2005-01-01

    Full text: Several intercomparison exercises were organized by the International Atomic Energy Agency (IAEA) on the determination of operational quantities at the regional or interregional basis. These exercises revealed significant differences in the approach, methods and assumptions, and consequently in the measurement results obtained by participating laboratories. In the East Asia region, the third phase of the Hp(10) intercomparison, organized within the frame of the Regional Cooperation Agreement (RCA) as a follow-up to previous exercises during 1990-92 and 1995-96, was completed mid-2004. The first phase grouped 25 laboratories from 16 member states, and 4 Secondary Standards Dosimetry Laboratories irradiated dosimeters in 6 different qualities for photon and beta radiations. In the second phase, 23 laboratories from 16 member states participated, and 3 Secondary Standards Dosimetry Laboratories provided irradiation in 5 different radiation qualities simulating workplace fields. The results of the second phase for the determination of operational quantities Hp(d) were satisfactory for all participating Member States, with marked improvement from the first phase; the laboratories demonstrated good performance in both quantities tested. These results underline the importance of such an intercomparison programme as a key element towards the harmonization of quantities and units on an international level. This paper presents the results of this RCA/IAEA intercomparison, and also the forthcoming RCA activities supporting intercomparison runs for the assessment of occupational exposure. Member states strongly recommend that the IAEA continue acting as a focal point for, inter alia, training in all forms, particularly in measurements and dosimetry techniques. This exercise also stressed the importance for the IAEA to take an active role in establishing a network of monitoring laboratories for radiation protection purposes, as it would provide for better information

  13. Second radiocarbon intercomparison program for the Chauvet-Pont d'Arc cave, Ardeche, France

    International Nuclear Information System (INIS)

    Quiles, A.; Valladas, H.; Kaltnecker, E.; Geneste, J.M.; Clottes, J.; Berthier, B.; Delque-Kolic, E.; Dumoulin, J.P.

    2014-01-01

    The Chauvet-Pont d'Arc Cave is one of the most important sites for the study of the earliest manifestations and development of prehistoric art at the beginning of the Upper Paleolithic. Different dating techniques have been performed thus far (AMS 14 C, U/Th TIMS, 36 Cl dating) to model the chronological framework of this decorated cave. The cave yielded several large charcoal fragments, which enabled the opportunity for obtaining multiple dates; thus, a First Radiocarbon Intercomparison Program (FIP) was initiated in 2004 using three charcoal pieces. The FIP demonstrated that those cross-dated samples belonged to a time period associated with the first human occupation. One of the statistical interests of an intercomparison program is to reduce the uncertainty on the sample age; thus, to further assess the accuracy of the chronological framework, the Second Intercomparison Program (SIP) involving 10 international 14 C laboratories was carried out on two pieces of charcoal found inside two hearth structures of the Galerie des Megaceros. Each laboratory used its own pretreatment and AMS facilities. In total, 21 and 22 measurements were performed, respectively, which yielded consistent results averaging ∼32 ka BP. Two strategies have currently been developed to identify statistical outliers and to deal with them; both lead to quasi-identical calibrated combined densities. Finally, the new results were compared with those of the FIP, leading to the important conclusion that five different samples from at least three different hearth structures give really tightened temporal densities, associated with one short human occupation in the Galerie des Megaceros. (authors)

  14. Result of the intercomparison exercise on radon measuring instruments and radon detectors 'bev- radon ring 2005'

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, A. [Vienna Univ. of Technology, Atominstitut, Wien (Austria); Maringer, F.J.; Michai, P.; Kreuziger, M. [BEV-Federal Office of Metrology and Surveying, Wien (Austria)

    2006-07-01

    In spring 2005 the Federal Office of Metrology and Surveying (B.E.V.) invited all in Austria working radon measuring institutes to an intercomparison exercise at the radon calibration laboratory in the Arsenal. The aim of this intercomparison was on the one hand an objective inquiry and documentation of the current metrological potential on the section of radon measurement in Austria - both quantitative and qualitative- and on the other hand an initiative for the participating laboratories to optimize and improve their applied calibration-, measurement and analyse technique. Ten contacted Austrian radon laboratories were prepared to participate on the radon intercomparison exercise. The intercomparison exercise was carried out from 14. till 29. June at the radon calibration laboratory in the Arsenal of the B.E.V.. As radon emanation source a five stepped arranged, at the Arsenal built radon source was used. The source ( A.D.O.T.T.O. 1 is filled with a certified Ra- 226-standard solution of the Czech Metrological Institute (C.M.I.), Prag. A simple statistic based model was used for the evaluation and assessment of the results from the participants, which consider the statistic nature of the radioactive decay combined uncertainty. Altogether 183 measuring instruments participated the intercomparison exercise. Two reference measuring instruments, 22 active and 159 passive measuring instruments. The active measuring instruments formed 6 types of instruments and as passive radon detectors were 7 different types used from the participants. The positioning of the radon measuring instruments and detectors in the radon calibration laboratory was executed in regard to statistic points of view. From the active measuring instruments 17 could qualify and from the passive methods six from eight participants were in compliance to the given criteria. Radon measurements, which could have financial and economics relating implications (e.g. architectural redevelopment or

  15. BRDF Characterization and Calibration Inter-Comparison between Terra MODIS, Aqua MODIS, and S-NPP VIIRS

    Science.gov (United States)

    Chang, Tiejun; Xiong, Xiaoxiong (Jack); Angal, Amit; Wu, Aisheng

    2016-01-01

    The inter-comparison of reflective solar bands (RSB) between Terra MODIS, Aqua MODIS, and SNPP VIIRS is very important for assessment of each instrument's calibration and to identify calibration improvements. One of the limitations of using their ground observations for the assessment is a lack of the simultaneous nadir overpasses (SNOs) over selected pseudo-invariant targets. In addition, their measurements over a selected Earth view target have significant difference in solar and view angles, and these differences magnify the effects of Bidirectional Reflectance Distribution Function (BRDF). In this work, an inter-comparison technique using a semi-empirical BRDF model is developed for reflectance correction. BRDF characterization requires a broad coverage of solar and view angles in the measurements over selected pseudo-invariant targets. Reflectance measurements over Libya 1, 2, and 4 desert sites from both the Aqua and Terra MODIS are regressed to a BRDF model with an adjustable coefficient accounting for the calibration difference between the two instruments. The BRDF coefficients for three desert sites for MODIS bands 1 to 9 are derived and the wavelength dependencies are presented. The analysis and inter-comparison are for MODIS bands 1 to 9 and VIIRS moderate resolution radiometric bands (M bands) M1, M2, M4, M5, M7, M8, M10 and imaging bands (I bands) I1-I3. Results show that the ratios from different sites are in good agreement. The ratios between Terra and Aqua MODIS from year 2003 to 2014 are presented. The inter-comparison between MODIS and VIIRS are analyzed for year 2014.

  16. An intercomparison of Canadian external dosimetry processors for radiation protection

    International Nuclear Information System (INIS)

    1989-10-01

    The five Canadian external dosimetry processors have participated in a two-stage intercomparison. The first stage involved dosimeters to known radiation fields under controlled laboratory conditions. The second stage involved exposing dosimeters to radiation fields in power reactor working environments. The results for each stage indicated the dose reported by each processor relative to an independently determined dose and relative to the others. The results of the intercomparisons confirm the original supposition: namely that the average differences in reported dose among five processors are much less than the uncertainty limits recommended by the ICRP. This report provides a description of the experimental methods as well as a discussion of the results for each stage. The report also includes a set of recommendations

  17. The April 1994 and October 1994 radon intercomparisons at EML

    International Nuclear Information System (INIS)

    Fisenne, I.M.; George, A.C.; Perry, P.M.; Keller, H.W.

    1995-10-01

    Quality assurance/quality control (QA/QC) are the backbone of many commercial and research processes and programs. QA/QC research tests the state of a functioning system, be it the production of manufactured goods or the ability to make accurate and precise measurements. The quality of the radon measurements in the US have been tested under controlled conditions in semi-annual radon gas intercomparison exercises sponsored by the Environmental Measurements Laboratory (EML) since 1981. The two Calendar Year 1994 radon gas intercomparison exercises were conducted in the EML exposure chamber. Thirty-two groups including US Federal facilities, USDOE contractors, national and state laboratories, universities and foreign institutions participated in these exercises. The majority of the participant's results were within ±10% of the EML value at radon concentrations of 570 and 945 Bq m -3

  18. Results of the 2001 NRPB intercomparison of passive radon detectors

    CERN Document Server

    Howarth, C B

    2002-01-01

    As in previous years, an intercomparison of passive radon detectors was held at NRPB in 2001. Forty-seven laboratories submitted 62 sets of passive detectors to this intercomparison. The exercise included three exposures to radon and its decay products at different equilibrium factors. An additional exposure at the CERN - EU high Energy Reference Facility (CERF) to a simulated cosmic ray spectrum was also offered to participants. After exposure, the detectors were returned to their originating laboratories for assessment. Participants reported the estimated exposure for each detector before they were notified of the exposures given to the detectors. The results obtained by participating laboratories were classified according to the spread of results from detectors exposed together and by the difference between the mean result of each group and the actual exposure given. Thirty-five percent of the laboratories achieved the highest classification for accuracy, while 9% were in the lowest category. The proportio...

  19. Intercomparison of radon gas detectors 1997 at PSI

    International Nuclear Information System (INIS)

    Schuler, Christoph; Butterweck-Dempewolf, Gernot

    1998-05-01

    Between Nov 14 and Nov 20, 1997, the Reference Laboratory for Radon Gas Activity Concentration Measurements at Paul Scherrer Institut performed the 1997 Radon Intercomparison Exercise. Radon gas detectors and instruments were exposed in the PSI Radon Chamber during seven days in a reference atmosphere with an average radon gas concentration of 3860 Bqm -3 . The majority of the participants at this intercomparison were Swiss Radon Gas Measurement Laboratories acknowledged by the Swiss Federal Office for Health. Criteria for this acknowledgement are a deviation of the measurement results to the reference value below 15% (traceability criterion) and a standard deviation of the mean of five detector measurement results below 15% (reproducibility criterion). With the exception of three participants, the results of electret ionisation chambers, track etch detectors and measuring instruments fulfilled the demanded traceability and reproducibility criteria. (author)

  20. Preparation and application of radioactive soil samples for intercomparison

    International Nuclear Information System (INIS)

    Gao Zequan; Li Zhou; Li Pengxiang; Wang Ruijun; Ren Xiaona

    2014-01-01

    This article summarized the preparation process and intercomparison results of the simulated environmental radioactive soil samples. The components of the matrix were: SiO 2 , Al 2 O 3 , Fe 2 O 3 , MgO, CaO, NaCl, KCl and TiO 2 . All of the components were milled, oven-dried, sieved and then blended together. The homogeneity test was according to GB 15000. 5-1994, and no significant differences were observed. The 3 H analysis soils were spiked natural soils with the moisture content of 15%. Eight laboratories attended this intercomparison. The results proves that the preparation of the simulated soils were suitable for the inter-laboratories comparison. (authors)

  1. Photon dosimetry intercomparisons at Tygerberg and Groote Schuur hospitals

    International Nuclear Information System (INIS)

    Jones, D.T.L.; Symons, J.E.; Schreuder, A.N.; Van der Merwe, E.J.; Rossouw, A.; Hough, J.K.; Lazarus, G.L.

    1994-08-01

    A national photon dosimetry intercomparison was undertaken at 8 hospitals at the beginning of 1989 prior to the commencement of randomised clinical trials involving neutron therapy at the National Accelerator Centre. The results obtained were in agreement at all but two hospitals. Following these studies it was agreed that a uniform photon dosimetry protocol, the AAPM TG2 protocol, be adopted countrywide. The clinical program at the National Accelerator Centre is now far advanced and it was deemed appropriate to undertake a new photon dosimetry intercomparison at two local hospitals, through which all patients are referred. The procedure involved was to compare the doses measured at each hospital under specified conditions by National Accelerator staff with the doses measured by the hospital physicists using their own equipment and protocols. The results obtained were in good agreement, confirming the validity of the dosimetry techniques used. 8 refs., 8 tabs

  2. Intercomparisons in the radiation monitoring network of the Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Tuckova, S; Malatova, I [National Radiation Protection Inst., Prague (Czech Republic); Drabova, D [State Office for Nuclear Safety, Prague (Czech Republic)

    1996-12-31

    In Czech Republic, altogether 11 laboratories, equipped by semiconductor gamma spectrometry supply regularly to the Centre of Radiation Monitoring Network the measured data about the radionuclide activity concentration in different environmental samples, participating thus in monitoring of radiation situation in the country. The Center of Radiation Monitoring Network of Czech Republic periodically organizes through its reference laboratories interlaboratory comparison tests ensuring thus quality of the measurements within the radiation monitoring network. A ring intercomparison test was organized in 1994. The piece of steel rather highly contaminated by {sup 60}Co was used. In the intercomparison test 1994-1995 of pulverized concrete breeze-block containing fly ash with natural radionuclides were used. Results of this measurement is given as an example (authors).

  3. Spectroradiometer Intercomparison and Impact on Characterizing Photovoltaic Device Performance: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Habte, A.; Andreas, A.; Ottoson, L.; Gueymard, C.; Fedor, G.; Fowler, S.; Peterson, J.; Naranen, E.; Kobashi, T.; Akiyama, A.; Takagi, S.

    2014-11-01

    Indoor and outdoor testing of photovoltaic (PV) device performance requires the use of solar simulators and natural solar radiation, respectively. This performance characterization requires accurate knowledge of spectral irradiance distribution that is incident on the devices. Spectroradiometers are used to measure the spectral distribution of solar simulators and solar radiation. On September 17, 2013, a global spectral irradiance intercomparison using spectroradiometers was organized by the Solar Radiation Research Laboratory (SRRL) at the National Renewable Energy Laboratory (NREL). This paper presents highlights of the results of this first intercomparison, which will help to decrease systematic inter-laboratory differences in the measurements of the outputs or efficiencies of PV devices and harmonize laboratory experimental procedures.

  4. Tropospheric ozone lidar intercomparison experiment, TROLIX '91, field phase report

    International Nuclear Information System (INIS)

    Boesenberg, J.; Ancellet, G.; Bergwerff, H.; Cossart, G. v.; Fiedler, J.; Jonge, C. de; Mellqvist, J.; Mitev, V.; Sonnemann, G.; Swart, D.; Wallinder, E.

    1993-01-01

    The Tropospheric Ozone Lidar Intercomparison Experiment TROLIX '91 has been initiated as part of the TESLAS subproject of the cooperative programme EUROTRAC. It has been performed in June 1991 at the Rijksinstitut voor Volksgezondheid en Milieuhygiene (RIVM) in Bilthoven, The Netherlands. The experiment was based on the simultaneous operation of different types of differential absorption lidars (DIAL), a special version of a Differential Optical Absorption Spectroscopy Instrument (DOAS), helicopter borne in situ instruments, and many other supporting measurements. After a short introduction to the general methodology the instruments are described, the experimental operations are explained, and a selection of data are presented. Some examples are given for the results of the intercomparison, as far as they have been available at the present stage of evaluation. The main purpose of this report, however, is to provide an overview over the material collected during the experiment, on order to facilitate further detailed studies in cooperation between the different groups which have participated. (orig.)

  5. Development of a transfer instrument for neutron dosimetry intercomparison

    International Nuclear Information System (INIS)

    Greene, D.; Miles, J.

    1974-01-01

    Comparisons are reported for fast neutron dosemeters which were designed to be transportable so as to enable intercomparisons between institutions using neutrons for radiotherapy or radiobiology. The systems considered are : 1) the ferrous sulphate dosemeter, 2) the lithium fluoride thermoluminescent dosemeter, 3) ionization chambers with various walls and gases. Work on photographic film dosimetry indicated that the system was not suitable and was not pursued. The sources used were 60 Co, the cyclotron at Hammersmith Hospital in London and 252 Cf

  6. GODAE Inter-Comparisons in the Tasman and Coral Seas

    Science.gov (United States)

    2012-08-01

    and salinity. All have their strengths and weaknesses, and each system out-performs all others in one aspect or another. With few exceptions, all... Auckland and Fiji (Fig 1), was occupied during the inter- comparison period. The observed T section from this line is shown in Fig 6a. Comparisons of T...has certain strengths and weaknesses. Inter-comparisons are regarded as valuable exer- cises that provide important insights into the ocean forecast

  7. The 2008 intercomparison exercise for radon gas measurement instruments at PSI; Die Vergleichsmessung 2008 fuer Radongasmessgeraete am PSI

    Energy Technology Data Exchange (ETDEWEB)

    Butterweck, G.; Schuler, Ch.; Mayer, S.

    2010-09-15

    Sixteen radon measurement services participated in the 2008 Radon Intercomparison Exercise performed at the Reference Laboratory for Radon Gas Activity Concentration Measurements at the Paul Scherrer Institute (PSI) during August 28{sup th} to September 7{sup th}, 2008 on behalf of the Swiss Federal Office of Public Health (FOPH). Twelve of these laboratories were approved by the FOPH and their participation in the intercomparison exercise was a requirement to warrant quality of measurement. Radon gas dosemeters (etched-track, electronic and electret ionisation chambers) and instruments (ionization chambers) were exposed in the PSI Radon Chamber in a reference atmosphere with an average radon gas concentration of 627 Bq m{sup -3} leading to a radon gas exposure of 155 kBq h m{sup -3}. One measuring instrument participating for testing purposes stored values for part of the exposure interval (30.8. - 7.9.2008). The exposure during this partial interval was 117 kBq h m{sup -3} at an average radon gas concentration of 624 Bq m{sup -3}. The exposure of 155 kBq h m{sup -3} was the lowest used at the PSI intercomparisons down to the present day. Especially the LLT electret ionisation chambers used by some of the laboratories reached the lower end of their measurement range with this exposure. Unexpected deviations of instruments of the same model seem to show a dependence on the serial number and thus production date. (authors)

  8. A soil sampling intercomparison exercise for the ALMERA network

    International Nuclear Information System (INIS)

    Belli, Maria; Zorzi, Paolo de; Sansone, Umberto; Shakhashiro, Abduhlghani; Gondin da Fonseca, Adelaide; Trinkl, Alexander; Benesch, Thomas

    2009-01-01

    Soil sampling and analysis for radionuclides after an accidental or routine release is a key factor for the dose calculation to members of the public, and for the establishment of possible countermeasures. The IAEA organized for selected laboratories of the ALMERA (Analytical Laboratories for the Measurement of Environmental Radioactivity) network a Soil Sampling Intercomparison Exercise (IAEA/SIE/01) with the objective of comparing soil sampling procedures used by different laboratories. The ALMERA network is a world-wide network of analytical laboratories located in IAEA member states capable of providing reliable and timely analysis of environmental samples in the event of an accidental or intentional release of radioactivity. Ten ALMERA laboratories were selected to participate in the sampling exercise. The soil sampling intercomparison exercise took place in November 2005 in an agricultural area qualified as a 'reference site', aimed at assessing the uncertainties associated with soil sampling in agricultural, semi-natural, urban and contaminated environments and suitable for performing sampling intercomparison. In this paper, the laboratories sampling performance were evaluated.

  9. Primary standardization of cesium-137 for international intercomparison

    International Nuclear Information System (INIS)

    Srivastava, P.K.

    1977-01-01

    Primary standards of cesium-137 are of great importance for precise radiation measurements because, due to its simple decay-scheme and long half-life, it is widely used for the calibration of radiation detectors. Also 137 Cs is used for the measurement of fission-yield and uranium burn-up in reactor engineering studies. In view of these, an international intercomparison was organised on a limited scale to correlate the standards established at the Bhabha Atomic Research Centre (BARC), Bombay(India) and Physikalisch-Technische Bundesanstalt (PTB), West Germany. The ''efficiency tracing technique'' was developed at BARC for the primary standardization of 137 Cs for this intercomparison. Two tracers, namely 82 Br and 60 Co, were employed to trace the beta efficiency of the 4 πβ-γ coincidence counting system. It is shown that this technique offers high accuracy and inherent reliability. The ''tracing-technique'' for 137 Cs standardization is briefly described. The gravimetric method of dilution and preparation of mixed sources of 137 Cs - 82 Br and 137 Cs - 60 Co are given. The various counting parameters and settings are included. Data reduction and the estimation of systematic and statistical errors are discussed. The results of the intercomparison, which are also included, show that the agreement between the measurments of BARC and PTB is within 0.5%. (author)

  10. A soil sampling intercomparison exercise for the ALMERA network

    Energy Technology Data Exchange (ETDEWEB)

    Belli, Maria [Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Via di Castel Romano 100, I-00128 Roma (Italy)], E-mail: maria.belli@apat.it; Zorzi, Paolo de [Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Via di Castel Romano 100, I-00128 Roma (Italy)], E-mail: paolo.dezorzi@isprambiente.it; Sansone, Umberto [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria)], E-mail: u.sansone@iaea.org; Shakhashiro, Abduhlghani [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria)], E-mail: a.shakhashiro@iaea.org; Gondin da Fonseca, Adelaide [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria)], E-mail: a.gondin-da-fonseca-azeredo@iaea.org; Trinkl, Alexander [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria)], E-mail: a.trinkl@iaea.org; Benesch, Thomas [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, A-2444 Seibersdorf (Austria)], E-mail: t.benesch@iaea.org

    2009-11-15

    Soil sampling and analysis for radionuclides after an accidental or routine release is a key factor for the dose calculation to members of the public, and for the establishment of possible countermeasures. The IAEA organized for selected laboratories of the ALMERA (Analytical Laboratories for the Measurement of Environmental Radioactivity) network a Soil Sampling Intercomparison Exercise (IAEA/SIE/01) with the objective of comparing soil sampling procedures used by different laboratories. The ALMERA network is a world-wide network of analytical laboratories located in IAEA member states capable of providing reliable and timely analysis of environmental samples in the event of an accidental or intentional release of radioactivity. Ten ALMERA laboratories were selected to participate in the sampling exercise. The soil sampling intercomparison exercise took place in November 2005 in an agricultural area qualified as a 'reference site', aimed at assessing the uncertainties associated with soil sampling in agricultural, semi-natural, urban and contaminated environments and suitable for performing sampling intercomparison. In this paper, the laboratories sampling performance were evaluated.

  11. Reactor neutron activation analysis on reference materials from intercomparison runs

    International Nuclear Information System (INIS)

    Pantelica, A.; Salagean, M.

    2003-01-01

    A review of using the Instrumental Neutron Activation Analysis (INAA) technique in our laboratory to determine major, minor and trace elements in mineral and biological samples from international intercomparison runs organised by IAEA Vienna, IAEA-MEL Monaco, 'pb-anal' Kosice, INCT Warszawa and IPNT Krakow is presented. Neutron irradiation was carried out at WWR-S reactor in Bucharest (short and long irradiation) during 1982-1997 and at TRIGA reactor in Pitesti (long irradiation) during the later period. The following type of materials were analysed: soils, marine sediments, uranium phosphate ore, water sludge, copper flue dust, whey powder, yeast, cereal flour (rye and wheat), marine animal tissue (mussel, garfish and tuna fish), as well as vegetal tissue (seaweed, cabbage, spinach, alfalfa, algae, tea leaves and herbs). The following elements could be, in general, determined: Ag, As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, Hg, K, La, Lu, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, W, Yb and Zn of long-lived radionuclides, as well as Al, Ca, Cl, Cu, Mg, Mn, and Ti of short-lived radionuclides. Data obtained in our laboratory for various matrix samples presented and compared with the intercomparison certified values. The intercomparison exercises offer to the participating laboratories the opportunity to test the accuracy of their analytical methods as well as to acquire valuable Reference Materials/ standards for future analytical applications. (authors)

  12. Psacoin level 1A intercomparison probabilistic system assessment code (PSAC) user group

    International Nuclear Information System (INIS)

    Nies, A.; Laurens, J.M.; Galson, D.A.; Webster, S.

    1990-01-01

    This report describes an international code intercomparison exercise conducted by the NEA Probabilistic System Assessment Code (PSAC) User Group. The PSACOIN Level 1A exercise is the third of a series designed to contribute to the verification of probabilistic codes that may be used in assessing the safety of radioactive waste disposal systems or concepts. Level 1A is based on a more realistic system model than that used in the two previous exercises, and involves deep geological disposal concepts with a relatively complex structure of the repository vault. The report compares results and draws conclusions with regard to the use of different modelling approaches and the possible importance to safety of various processes within and around a deep geological repository. In particular, the relative significance of model uncertainty and data variability is discussed

  13. DRDC Ottawa Participation in the SILENE Accident Dosimetry Intercomparison Exercise. June 10-21, 2002

    National Research Council Canada - National Science Library

    Prud'homme-Lalonde, L

    2002-01-01

    .... The SILENE International Accident Dosimetry Intercomparison Exercise at Valduc, France in June 2002 coincided with DRDC Ottawa work designed to refine its proposed criticality dosimetry system...

  14. Dosimetry audits and intercomparisons in radiotherapy: A Malaysian profile

    International Nuclear Information System (INIS)

    Noor, Noramaliza M.; Nisbet, A.; Hussein, M.; Chu S, Sarene; Kadni, T.; Abdullah, N.; Bradley, D.A.

    2017-01-01

    Quality audits and intercomparisons are important in ensuring control of processes in any system of endeavour. Present interest is in control of dosimetry in teletherapy, there being a need to assess the extent to which there is consistent radiation dose delivery to the patient. In this study we review significant factors that impact upon radiotherapy dosimetry, focusing upon the example situation of radiotherapy delivery in Malaysia, examining existing literature in support of such efforts. A number of recommendations are made to provide for increased quality assurance and control. In addition to this study, the first level of intercomparison audit i.e. measuring beam output under reference conditions at eight selected Malaysian radiotherapy centres is checked; use being made of 9 µm core diameter Ge-doped silica fibres (Ge-9 µm). The results of Malaysian Secondary Standard Dosimetry Laboratory (SSDL) participation in the IAEA/WHO TLD postal dose audit services during the period between 2011 and 2015 will also been discussed. In conclusion, following review of the development of dosimetry audits and the conduct of one such exercise in Malaysia, it is apparent that regular periodic radiotherapy audits and intercomparison programmes should be strongly supported and implemented worldwide. The programmes to-date demonstrate these to be a good indicator of errors and of consistency between centres. A total of ei+ght beams have been checked in eight Malaysian radiotherapy centres. One out of the eight beams checked produced an unacceptable deviation; this was found to be due to unfamiliarity with the irradiation procedures. Prior to a repeat measurement, the mean ratio of measured to quoted dose was found to be 0.99 with standard deviation of 3%. Subsequent to the repeat measurement, the mean distribution was 1.00, and the standard deviation was 1.3%. - Highlights: • We review significant factors that impact upon radiotherapy dosimetry, • We carried out the

  15. The OptIC Data Assimilation Intercomparison: A Statistical Critique

    Science.gov (United States)

    Enting, I. G.; Clisby, N.

    2008-12-01

    The development of improved terrestrial carbon models has assumed great importance because of concerns about significant climate-to-carbon feedback processes. The complexity of the interactions leads to considerable difficulties in the process of model calibration. The OptIC intercomparison explored some aspects of model calibration, using an idealised terrestrial carbon model. Participants were invited to estimate model parameters in various cases defined by specified time series of the model state, with various forms of added noise. The study identified the crucial importance of the choice of cost function. The present analysis revisits the OptIC study, by considering it as an exercise in statistical estimation. This treats the observations as random variables. Consequently parameter estimates, â, based on observations will also be random variables whose distribution is known as the 'sampling distribution'. Key questions for any specific case are: Are departures from â/a_true =1 indication of bias or sampling error? Under what circumstance are uncertainty estimates (of Var[â]) reliable? We consider cases where the estimate is obtained by minimising a cost function, ΘX. Assuming that we know the true form of ℓ, the log likelihood, there are three different characterisations of uncertainty that should be distinguished: (i) The uncertainty from maximum-likelihood estimates, corresponding (either exactly or asymptotically) to the Cramer-Rao bound. In a realistic calibration situation, we won't be able to determine this because the 'true' form of the likelihood is unknown. (ii) The actual uncertainty associated with using a particular cost function. If the true noise distribution is known, this can be calculated in simple cases and determined from simulations in more complicated cases. (iii) The 'formal uncertainty' based on assuming (usually incorrectly) that ΘX is the true likelihood. In the first stage of the analysis, the distinctions are illustrated by

  16. Intracoin - International Nuclide Transport Code Intercomparison Study

    International Nuclear Information System (INIS)

    1984-09-01

    The purpose of the project is to obtain improved knowledge of the influence of various strategies for radionuclide transport modelling for the safety assessment of final repositories for nuclear waste. This is a report of the first phase of the project which was devoted to a comparison of the numerical accuracy of the computer codes used in the study. The codes can be divided into five groups, namely advection-dispersion models, models including matrix diffusion and chemical effects and finally combined models. The results are presented as comparisons of calculations since the objective of level 1 was code verification. (G.B.)

  17. Final Progress Report: Collaborative Research: Decadal-to-Centennial Climate & Climate Change Studies with Enhanced Variable and Uniform Resolution GCMs Using Advanced Numerical Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Fox-Rabinovitz, M; Cote, J

    2009-06-05

    The joint U.S-Canadian project has been devoted to: (a) decadal climate studies using developed state-of-the-art GCMs (General Circulation Models) with enhanced variable and uniform resolution; (b) development and implementation of advanced numerical techniques; (c) research in parallel computing and associated numerical methods; (d) atmospheric chemistry experiments related to climate issues; (e) validation of regional climate modeling strategies for nested- and stretched-grid models. The variable-resolution stretched-grid (SG) GCMs produce accurate and cost-efficient regional climate simulations with mesoscale resolution. The advantage of the stretched grid approach is that it allows us to preserve the high quality of both global and regional circulations while providing consistent interactions between global and regional scales and phenomena. The major accomplishment for the project has been the successful international SGMIP-1 and SGMIP-2 (Stretched-Grid Model Intercomparison Project, phase-1 and phase-2) based on this research developments and activities. The SGMIP provides unique high-resolution regional and global multi-model ensembles beneficial for regional climate modeling and broader modeling community. The U.S SGMIP simulations have been produced using SciDAC ORNL supercomputers. Collaborations with other international participants M. Deque (Meteo-France) and J. McGregor (CSIRO, Australia) and their centers and groups have been beneficial for the strong joint effort, especially for the SGMIP activities. The WMO/WCRP/WGNE endorsed the SGMIP activities in 2004-2008. This project reflects a trend in the modeling and broader communities to move towards regional and sub-regional assessments and applications important for the U.S. and Canadian public, business and policy decision makers, as well as for international collaborations on regional, and especially climate related issues.

  18. Spatial inter-comparison of Top-down emission inventories in European urban areas

    Science.gov (United States)

    Trombetti, Marco; Thunis, Philippe; Bessagnet, Bertrand; Clappier, Alain; Couvidat, Florian; Guevara, Marc; Kuenen, Jeroen; López-Aparicio, Susana

    2018-01-01

    This paper presents an inter-comparison of the main Top-down emission inventories currently used for air quality modelling studies at the European level. The comparison is developed for eleven European cities and compares the distribution of emissions of NOx, SO2, VOC and PPM2.5 from the road transport, residential combustion and industry sectors. The analysis shows that substantial differences in terms of total emissions, sectorial emission shares and spatial distribution exist between the datasets. The possible reasons in terms of downscaling approaches and choice of spatial proxies are analysed and recommendations are provided for each inventory in order to work towards the harmonisation of spatial downscaling and proxy calibration, in particular for policy purposes. The proposed methodology may be useful for the development of consistent and harmonised European-wide inventories with the aim of reducing the uncertainties in air quality modelling activities.

  19. Intercomparison of whole-body averaged SAR in European and Japanese voxel phantoms

    International Nuclear Information System (INIS)

    Dimbylow, Peter J; Hirata, Akimasa; Nagaoka, Tomoaki

    2008-01-01

    This paper provides an intercomparison of the HPA male and female models, NORMAN and NAOMI with the National Institute of Information and Communications Technology (NICT) male and female models, TARO and HANAKO. The calculations of the whole-body SAR in these four phantoms were performed at the HPA, at NICT and at the Nagoya Institute of Technology (NIT). These were for a plane wave with a vertically aligned electric field incident upon the front of the body from 30 MHz to 3 GHz for isolated conditions. As well as investigating the general differences through this frequency range, particular emphasis was placed on the assumptions of how dielectric properties are assigned to tissues (particularly skin and fat) and the consequence of using different algorithms for calculating SAR at the higher frequencies.

  20. An international intercomparison of passive dosemeters, electronic dosemeters and dose rate meters used for environmental radiation measurements

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Thompson, I.M.G.

    1995-01-01

    during 1994. The intercomparison was organised by the Physikalisch Technische Bundesanstalt (PTB), Braunschweig, Germany, and by the Riso National Laboratory, Roskilde, Denmark. This paper describes the intercomparison experiments performed at the newly established Riso Natural Environmental Radiation...

  1. Intercomparison of a 'Bottom-up' and 'Top-down' Modeling Paradigm for estimating carbon and latent heat fluxes over a variety of vegetative regimes across the U.S., Agricultural and Forest Meteorology

    Science.gov (United States)

    Biophysical models intended for routine applications at a range of scales should attempt to balance the competing demands of generality and simplicity and be capable of realistically simulating the response of CO2 and energy fluxes to environmental and physiological forcings. At the same time they m...

  2. GEO-LEO reflectance band inter-comparison with BRDF and atmospheric scattering corrections

    Science.gov (United States)

    Chang, Tiejun; Xiong, Xiaoxiong Jack; Keller, Graziela; Wu, Xiangqian

    2017-09-01

    The inter-comparison of the reflective solar bands between the instruments onboard a geostationary orbit satellite and onboard a low Earth orbit satellite is very helpful to assess their calibration consistency. GOES-R was launched on November 19, 2016 and Himawari 8 was launched October 7, 2014. Unlike the previous GOES instruments, the Advanced Baseline Imager on GOES-16 (GOES-R became GOES-16 after November 29 when it reached orbit) and the Advanced Himawari Imager (AHI) on Himawari 8 have onboard calibrators for the reflective solar bands. The assessment of calibration is important for their product quality enhancement. MODIS and VIIRS, with their stringent calibration requirements and excellent on-orbit calibration performance, provide good references. The simultaneous nadir overpass (SNO) and ray-matching are widely used inter-comparison methods for reflective solar bands. In this work, the inter-comparisons are performed over a pseudo-invariant target. The use of stable and uniform calibration sites provides comparison with appropriate reflectance level, accurate adjustment for band spectral coverage difference, reduction of impact from pixel mismatching, and consistency of BRDF and atmospheric correction. The site in this work is a desert site in Australia (latitude -29.0 South; longitude 139.8 East). Due to the difference in solar and view angles, two corrections are applied to have comparable measurements. The first is the atmospheric scattering correction. The satellite sensor measurements are top of atmosphere reflectance. The scattering, especially Rayleigh scattering, should be removed allowing the ground reflectance to be derived. Secondly, the angle differences magnify the BRDF effect. The ground reflectance should be corrected to have comparable measurements. The atmospheric correction is performed using a vector version of the Second Simulation of a Satellite Signal in the Solar Spectrum modeling and BRDF correction is performed using a semi

  3. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

    2015-10-20

    Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

  4. Report on the intercomparison for the isotope standards limestone KH 2 and polyethylene foil PEF 1

    International Nuclear Information System (INIS)

    Gerstenberger, H.; Herrmann, M.

    1983-01-01

    The isotope abundance of 13 C and 18 O of a carbonate was measured by an intercomparison in order to create a new working standard for the mass spectrometric determination of isotopic variations in natural materials. For the same purpose a polyethylene was subjected an intercomparison and the abundance of 13 C and D has been determined. (author)

  5. Initial Results of an Intercomparison of AMS-Based Atmospheric 14CO2 Measurements

    NARCIS (Netherlands)

    Miller, John; Lehman, Scott; Wolak, Chad; Turnbull, Jocelyn; Dunn, Gregory; Graven, Heather; Keeling, Ralph; Meijer, Harro A. J.; Aerts-Bijma, Anita Th; Palstra, Sanne W. L.; Smith, Andrew M.; Allison, Colin; Southon, John; Xu, Xiaomei; Nakazawa, Takakiyo; Aoki, Shuji; Nakamura, Toshio; Guilderson, Thomas; LaFranchi, Brian; Mukai, Hitoshi; Terao, Yukio; Uchida, Masao; Kondo, Miyuki

    2013-01-01

    This article presents results from the first 3 rounds of an international intercomparison of measurements of Delta(CO2)-C-14 in liter-scale samples of whole air by groups using accelerator mass spectrometry (AMS). The ultimate goal of the intercomparison is to allow the merging of Delta(CO2)-C-14

  6. Dosimetry audits and intercomparisons in radiotherapy: A Malaysian profile

    Science.gov (United States)

    M. Noor, Noramaliza; Nisbet, A.; Hussein, M.; Chu S, Sarene; Kadni, T.; Abdullah, N.; Bradley, D. A.

    2017-11-01

    Quality audits and intercomparisons are important in ensuring control of processes in any system of endeavour. Present interest is in control of dosimetry in teletherapy, there being a need to assess the extent to which there is consistent radiation dose delivery to the patient. In this study we review significant factors that impact upon radiotherapy dosimetry, focusing upon the example situation of radiotherapy delivery in Malaysia, examining existing literature in support of such efforts. A number of recommendations are made to provide for increased quality assurance and control. In addition to this study, the first level of intercomparison audit i.e. measuring beam output under reference conditions at eight selected Malaysian radiotherapy centres is checked; use being made of 9 μm core diameter Ge-doped silica fibres (Ge-9 μm). The results of Malaysian Secondary Standard Dosimetry Laboratory (SSDL) participation in the IAEA/WHO TLD postal dose audit services during the period between 2011 and 2015 will also been discussed. In conclusion, following review of the development of dosimetry audits and the conduct of one such exercise in Malaysia, it is apparent that regular periodic radiotherapy audits and intercomparison programmes should be strongly supported and implemented worldwide. The programmes to-date demonstrate these to be a good indicator of errors and of consistency between centres. A total of ei+ght beams have been checked in eight Malaysian radiotherapy centres. One out of the eight beams checked produced an unacceptable deviation; this was found to be due to unfamiliarity with the irradiation procedures. Prior to a repeat measurement, the mean ratio of measured to quoted dose was found to be 0.99 with standard deviation of 3%. Subsequent to the repeat measurement, the mean distribution was 1.00, and the standard deviation was 1.3%.

  7. An intercomparison exercise on radionuclides in sediment samples

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, S.P.

    1996-07-01

    An intercomparison exercise on artificial and natural radionuclides in two sediment samples, one from the Baltic Sea and one from the Kattegat, has been carried out under the EKO-1 project or the Nordic Safety Research Programme (NKS) for the period 1996-97. The measurement techniques have included direct gamma-ray spectrometry with Ge and NaI detectors, and radiochemical procedures followed by beta counting and alpha spectrometry. The participants have 21 laboratories. Results were submitted for Cs-137, Cs-134, Co-60, Sb-125, Pu-239,240, Pu-238, Am-241, Sr-90, Ra-226, Th-232 and K-40, Pb-210, Po-210 and U-235. The analytical performance of the participants was evaluated for those radionuclides where six or more data sets were received. Statistical tests were made to see if individual results agreed with overall average radionuclide concentrations in the two sediment materials within target standard deviations. The results of these tests show that for Cs-137, Cs-134, Ra-226, Th-232 and K-40 the analytical performance criteria were not met for 20-40% of the data sets. For plutonium isotopes the tests show that the performance criteria were not met for 13% of the data sets. Tests of overall analytical performance show that 61% of the data sets do not meet the combined performance criteria. This shows that there is room for considerable improvement of analytical quality for most of the laboratories that have participated in this intercomparison. The intercomparison exercise has furthermore demonstrated several elementary problems in analytical work. (au) 57 tabs., 16 ills., 1 ref.

  8. Australian participation in international intercomparisons of environmental dosemeters

    International Nuclear Information System (INIS)

    Boas, J.F.; David, R.C.; Jones, J.

    2002-01-01

    The Environmental Measurements Laboratory of the U.S. Department of Energy has conducted international intercomparisons of environmental dosemeters at regular intervals since 1974. This paper reports the results obtained in the 10th and 11th intercomparisons by JFB and JGY at the Australian Radiation Laboratory (in 1992 and 1996 respectively) and in the 12th intercomparison by JFB and DRCT at the Australian Radiation Protection and Nuclear Safety Agency and by JGY and JJ at Australian Radiation Serviceces during 2000 and 2001. The ARL/ARPANSA measurements used a simple dosemeter holder containing two CaSO 4 :Dy impregnated Teflon discs, one unshielded and the other shielded by approximately 2.4 mm of Cu. The ARS measurements used a commercially available TLD badge case containing a CaSO 4 :Dy impregnated Teflon card. The commercial badge case was not symmetrical in design. The filtration in the front and rear sections of the commercial badge case varied from an open area to an area shielded by copper, tin and cadmium. The results obtained were generally within ±15% of the reference values measured by EML using high-pressure ionisation chambers for dosemeters exposed hi the field to environmental radiation and for dosemeters given a single exposure to 137 Cs or 241 Am at EML or an associated laboratory. Similar agreement was obtained for dosemeters exposed in the field and also given a single exposure to 137 Cs radiation. In order to obtain this measure of agreement, the dosemeters were individually calibrated and the readouts corrected for fading. Copyright (2002) Australasian Radiation Protection Society Inc

  9. An intercomparison exercise on radionuclides in sediment samples

    International Nuclear Information System (INIS)

    Nielsen, S.P.

    1996-07-01

    An intercomparison exercise on artificial and natural radionuclides in two sediment samples, one from the Baltic Sea and one from the Kattegat, has been carried out under the EKO-1 project or the Nordic Safety Research Programme (NKS) for the period 1996-97. The measurement techniques have included direct gamma-ray spectrometry with Ge and NaI detectors, and radiochemical procedures followed by beta counting and alpha spectrometry. The participants have 21 laboratories. Results were submitted for Cs-137, Cs-134, Co-60, Sb-125, Pu-239,240, Pu-238, Am-241, Sr-90, Ra-226, Th-232 and K-40, Pb-210, Po-210 and U-235. The analytical performance of the participants was evaluated for those radionuclides where six or more data sets were received. Statistical tests were made to see if individual results agreed with overall average radionuclide concentrations in the two sediment materials within target standard deviations. The results of these tests show that for Cs-137, Cs-134, Ra-226, Th-232 and K-40 the analytical performance criteria were not met for 20-40% of the data sets. For plutonium isotopes the tests show that the performance criteria were not met for 13% of the data sets. Tests of overall analytical performance show that 61% of the data sets do not meet the combined performance criteria. This shows that there is room for considerable improvement of analytical quality for most of the laboratories that have participated in this intercomparison. The intercomparison exercise has furthermore demonstrated several elementary problems in analytical work. (au) 57 tabs., 16 ills., 1 ref

  10. IAEA/IDEAS intercomparison exercise on internal dose assessment

    International Nuclear Information System (INIS)

    Doerfel, H.; Andrasi, A.; Cruz-Suarez, R.; Castellani, C. M.; Hurtgen, C.; Marsh, J.; Zeger, J.

    2007-01-01

    An Internet based intercomparison exercise on assessment of occupational exposure due to intakes of radionuclides has been performed to check the applicability of the 'General Guidelines for the Assessment of Internal Dose from Monitoring Data' developed by the IDEAS group. There were six intake cases presented on the Internet and 81 participants worldwide reported solutions to these cases. Results of the exercise indicate that the guidelines have a positive influence on the methodologies applied for dose assessments and, if correctly applied, improve the harmonisation of assessed doses. (authors)

  11. ENDFIC - A program for indexing and intercomparison of ENDFs

    International Nuclear Information System (INIS)

    Gopalakrishnan, V.; Devan, K.

    1995-01-01

    The program ENDFIC, a nuclear data utility program in FORTRAN, was written under contract on 'Indexing and Intercomparison Programme of Evaluated Nuclear Data Files' (No. 7866/RB/TC), between Indira Gandhi Centre for Atomic Research, Kalpakkam, and the International Atomic Energy Agency, Vienna. The program can be used for the following two activities: i. INFO activity: to find from a given ENDF/B formatted evaluated nuclear data library, information regarding the contents of the library; ii. COMP activity: to do comparison of cross sections from several given ENDF libraries. 1 ref

  12. Intercomparison of 131I activity measurements in nuclear medicine

    International Nuclear Information System (INIS)

    Kim, G. Y.; Yang, H. K.; Lim, C. I.; Lee, H. K.; Jeong, H. K.

    2004-01-01

    Activity measurements in nuclear medicine using a dose calibrator have been performed for several decades and their reliability has varied. To minimise the radiation dose to patients with radionuclides, it is necessary to ensure that the sample administered is accurately assayed. Recognizing the importance of intercomparison in nuclear medicine and the need to make access to activity standards traceable to the international measurement system, the KFDA, as a national secondary standard dosimetry laboratory (SSDL), started an intercomparison program in 2002. This program was initiated by survey to all nuclear medicine centres regarding general information about their dose calibrators, radioisotopes etc. 71 nuclear medicine centres (79 dose calibrators) participated in the intercomparison program with 131 I isotope. To assess the accuracy of clinical measurements of the activity of 131 I solutions and to determine the reason for the disagreement, an intercomparison was conducted using 4 ml aliquots in 10 ml P6 vial with a total activity in the region of 10 -20 MBq. The reference time of decay for all solutions was 0:00 on 25 September 2002. The half-life used was 8.04 days. For the evaluation of solution in KFDA, a sealed, high pressure and re-entrant ionisation chamber, NPL-CRC radionuclide calibrators were used. The verification of our calibration quality was by means of a comparison with the Korea Primary Standard Laboratory (KRISS). The activity ratio of KFDA to KRISS for the 131 I solutions is 1.011. The difference between the value quoted by the clinic, A hospital and the value obtained by the KFDA, A KFDA , is expressed as a percent deviation, i.e. DEV(%) 100x(A hospital -A KFDA )/A KFDA . From the data obtained it was found that 61% of the calibrators showed a deviation within +/-5%; 23% had a deviation in the range 5% 131 I solution activity measurements, using dose calibrators in Koreas, and also to provide the participants with a traceable standard to

  13. Methods and advantages of intercomparisons of TLDs for environmental monitoring

    International Nuclear Information System (INIS)

    Ranogajec-Komor, M.; Klemic, G.

    1997-01-01

    One of the most difficult tasks facing the international community is the monitoring of environmental radiation for potential increases due to facility accidents or weapons activity. Monitoring networks have been established to provide a record of natural background radiation as well as measure any radiation releases from a facility. Thermoluminescent dosimeters (TLDs) are an important element of such networks and are the most widely used passive detector for environmental monitoring. In order to reach a high international standard in the application of TLDs in routine environmental monitoring, there is a need for a intercomparisons. (authors)

  14. Intercomparison of radiation protection instruments based on microdosimetric principles

    International Nuclear Information System (INIS)

    Dietze, G.; Guldbakke, S.; Kluge, H.; Schmitz, T.

    1986-11-01

    Dosemeters based on low-pressure tissue-equivalent proportional counters were developed for the application in radiation protection area monitoring by several groups in Europe. Five different prototypes have been intercompared in a 60 Co photon field, in monoenergetic neutron fields with various energies between 73 keV and 5 MeV and in three neutron fields at a 252 Cf source moderated by a D 2 O sphere. This report describes the radiation fields, the measuring devices and first results of the intercomparison. Additional measurements with a system used in microdosimetry and with a conventional dose equivalent rate meter for neutrons (Rem Counter) were also described. (orig.) [de

  15. International nuclear accident dosimetry intercomparison: results of Czech participation

    International Nuclear Information System (INIS)

    Spurny, F.; Votockova, I.

    1996-01-01

    An international intercomparison scheme for criticality accident dosimetry systems took place at the SILENE reactor, Valduc, France in June 1993. The dosemeters were exposed both on phantoms and in free air to radiation from the reactor, both shielded by lead and bare. The results obtained during this event by Czech participants are presented and compared with the average values obtained by the complete group of participants and with the reference values. The systems used consisted mostly of Si-diodes and thermoluminescent detectors, some supporting measurements were performed with solid state nuclear track detectors and using the albedo principle. The agreement between the data sets is very good. 7 tabs., 13 refs

  16. Intercomparison of radionuclide measurements in marine sediment sample IAEA-368

    International Nuclear Information System (INIS)

    Ballestra, S.; Lopez, J.J.; Gastaud, J.; Parsi, P.; Vas, D.; Noshkin, V.

    1991-08-01

    The results of an intercomparison exercise on a Pacific Ocean sediment sample, IAEA-368, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 89 laboratories representing 37 countries have been evaluated. The following are the recommended values, with confidence intervals, for 60 Co, 155 Eu, 210 7Pb, 226 Ra, 238 U, 238 Pu and 239+240 Pu (Reference date: 1 January 1990). Information values for 40 K, 90 Sr, 137 Cs, 228 Th, 230 Th, 232 Th, 234 U, 235 U and 241 Am are also reported. (author)

  17. Intercomparison of radionuclide measurements in marine sediment sample IAEA-367

    International Nuclear Information System (INIS)

    Ballestra, S.; Lopez, J.J.; Gastaud, J.; Vas, D.; Noshkin, V.

    1991-08-01

    The results of an intercomparison exercise on a Pacific Ocean sediment sample, IAEA-367, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 81 laboratories representing 37 countries have been evaluated. The following are the recommended values, with confidence intervals, for 60 Co, 90 Sr, 137 Cs, 239+240 Pu (Reference date: 1 January 1990). Information values for 155 Eu, 238 Pu, 241 Am, and 241 Pu are reported. Information values for the following natural radionuclides 40 K, 226 Ra, 228 Th, 230 Th, 234 U, 235 U and 238 U are also reported. (author)

  18. The inspirations with a radioactive intercomparison on a wine sample

    International Nuclear Information System (INIS)

    Su Qiong

    1993-12-01

    The methods used and results in a radioactive intercomparison on a wine sample are reported, which was organized by WHO-IRC in May, 1992. In order to analyse and compare the results obtained by all laboratories from WHO-IRC report (IRC NOTE No.41, 1993) are given. A re-measured new result about nuclide 40 K in the sample is also reported which coincides quite well with the result reported to IRC in a deviation of less than +-1%. And the problems concerning 'reference values' and standard sources etc. are also discussed

  19. Inter-comparison of ice sheet mass balance products from GRACE: ESA CCI Round Robin results

    DEFF Research Database (Denmark)

    Groth, A.; Horwath, M.; Horvath, A.

    -term satellite-based data products are generated for selected ECVs. Since ice sheet mass balance is an ECV parameter of highest interest, both the AIS_cci and the GIS_cci project will provide mass balance products based on satellite gravimetry data: (a) time series of monthly mass changes for individual drainage...... basins, and (b) gridded mass changes covering the entire ice sheet.Gravimetry Mass Balance (GMB) products are derived from data acquired by the GRACE (Gravity Recovery and Climate Experiment) mission. Although GRACE data have the advantage of being directly sensitive to mass changes, their limited...... drainage basins the GMB time series are compared to independent mass balance products based on satellite altimetry and firn densification information from a regional climate model. This inter-comparison has aided the algorithm definition for the operational ECV production....

  20. RCA/IAEA third external dosimetry intercomparisons in East Asia region

    International Nuclear Information System (INIS)

    Yamamoto, H.; Yoshizawa, M.; Murakami, H.; Momose, T.; Tsujimura, N.; Kanai, K.; Cruz-Suarez, R.

    2007-01-01

    Several intercomparison exercises were organised by the International Atomic Energy Agency (IAEA) on the determination of operational quantities at the regional or inter-regional basis. In East Asia region, a third phase of the intercomparison finished in mid 2004. It was organised within the frame of the Regional Cooperation Agreement (RCA) as a follow-up to previous exercises carried out during 1990-1992 and 1995-1996. The results of this intercomparison for the determination of operational quantities were satisfactory for all Member States. The laboratories demonstrated a good performance in quantities tested. The purpose of this paper is to present the results of the RCA/IAEA intercomparison and the future of RCA activities in support of assessment of occupational exposure by organising intercomparison runs. (authors)

  1. Eurados self-sustained programme of intercomparisons for individual monitoring services

    International Nuclear Information System (INIS)

    Grimbergen, T. W. M.; Figel, M.; Romero, A. M.; Stadtmann, H.; McWhan, A. F.

    2011-01-01

    Within EURADOS working group 2, a system for self-sustained intercomparisons for individual monitoring services for external radiation was developed. With the intercomparison results, the participants can show compliance within their quality management system, compare their results with those from other participants and develop plans for improvement of their system. The costs of the exercises are covered by the participants fees. In this programme, the first intercomparison exercise for whole-body dosemeters has been executed in 2008 with 62 participating dosimetry systems from participants across Europe. In general, film systems show the largest deviations, although the results of some participants indicate that it is possible to achieve results with a film system with similar quality as for thermoluminescence dosimetry (TLD) systems. A second intercomparison has been organised for extremity dosemeters in 2009. For 2010 it is planned to organise a second intercomparison for whole-body dosemeters. (authors)

  2. Safety criteria: Intercomparison and aggregation of risks

    International Nuclear Information System (INIS)

    Yadigaroglu, G.

    1987-08-01

    Review of the assumptions underlying the use of limit lines in nuclear regulation and risk comparisons led to an alternative approach, where frequency-consequence curves are divided into two components: number of accidents during a specified time period and consequences conditional upon the occurrence of an unwanted event. This approach leads to a neat separation between natural and technological disasters. To compare probability distributions when stochastic dominance principles are not applicable, risk indices based on a linearized moments model (LMM) were established. The LMM permits explicit introduction of individual, societal or group opinions, thus incorporating the various perceptions of risks by society directly into the evaluation process. A questionnaire was applied to elicit empirical data which were then compared with the predictions of the linearized moments model. Furthermore the LMM also allows the comparison of events in those cases where the cumulative probability distributions cross each other. For the evaluation of a probability distribution that crosses the limit line, the risk index of the limit line (calculated by using the LMM) should be compared to the index of the accident under consideration

  3. Intercomparison of aerosol-cloud-precipitation interactions in stratiform orographic mixed-phase clouds

    Science.gov (United States)

    Muhlbauer, A.; Hashino, T.; Xue, L.; Teller, A.; Lohmann, U.; Rasmussen, R. M.; Geresdi, I.; Pan, Z.

    2010-09-01

    Anthropogenic aerosols serve as a source of both cloud condensation nuclei (CCN) and ice nuclei (IN) and affect microphysical properties of clouds. Increasing aerosol number concentrations is hypothesized to retard the cloud droplet coalescence and the riming in mixed-phase clouds, thereby decreasing orographic precipitation. This study presents results from a model intercomparison of 2-D simulations of aerosol-cloud-precipitation interactions in stratiform orographic mixed-phase clouds. The sensitivity of orographic precipitation to changes in the aerosol number concentrations is analysed and compared for various dynamical and thermodynamical situations. Furthermore, the sensitivities of microphysical processes such as coalescence, aggregation, riming and diffusional growth to changes in the aerosol number concentrations are evaluated and compared. The participating numerical models are the model from the Consortium for Small-Scale Modeling (COSMO) with bulk microphysics, the Weather Research and Forecasting (WRF) model with bin microphysics and the University of Wisconsin modeling system (UWNMS) with a spectral ice habit prediction microphysics scheme. All models are operated on a cloud-resolving scale with 2 km horizontal grid spacing. The results of the model intercomparison suggest that the sensitivity of orographic precipitation to aerosol modifications varies greatly from case to case and from model to model. Neither a precipitation decrease nor a precipitation increase is found robustly in all simulations. Qualitative robust results can only be found for a subset of the simulations but even then quantitative agreement is scarce. Estimates of the aerosol effect on orographic precipitation are found to range from -19% to 0% depending on the simulated case and the model. Similarly, riming is shown to decrease in some cases and models whereas it increases in others, which implies that a decrease in riming with increasing aerosol load is not a robust result

  4. BIPM project: Intercomparison of water triple-point cells

    Science.gov (United States)

    Chattle, M. V.; Butler, J.

    1994-12-01

    The paper presents the results of an intercomparison between 3 triple point of water cells circulated by the Bureau International des Poids et Measures (BIPM), and a cell which is one of those used as a reference cell at the National Physical Laboratory (NPL). All 4 cells were prepared, stored and measured in the manner normally adopted at NPL. The results of the intercomparison show that over the course of about 6 weeks the temperatures of the 3 circulated cells generally agreed within 0.20 mK, with a maximum difference of 0.27(7) mK. Over the same period, the total variations of temperature measured in the 3 individual cells were 0.04 mK, 0.08 mK and 0.18 mK, respectively; the NPL cell varied by 0.10 mK. Gallium point measurements made over a similar period confirmed that these differences were partly due to small drifts in the thermometer resistance or in the measuring system.

  5. PIDIE, plutonium isotopic determination inter-comparison exercise

    International Nuclear Information System (INIS)

    Harry, R.J.S.

    1990-07-01

    PIDIE (Plutonium Isotopic Determination Inter-comparison Exercise) is one of the projects of the ESARDA Working Group on Techniques and Standards for Non-Destructive Analysis. PIDIE is placed against the historical background of the general development of international standards. Its results are also reviewed in the light of the original purpose of the project. Sets of seven sealed Pu samples of different isotopic composition, each containing 0,45 grammes, were sent to the 9 participating laboratories for three separate determinations of the unknown isotopic composition, to investigate error sources and , if possible to improve the knowledge of γ-emission probabilities. An additional question was to examine the possible improvement of such measurements using reference samples. No important bias has been observed in the results of this inter-comparison. The apparent improvement in the precision and accuracy of the result seems to arise from both better equipment and more elaborate spectrum evaluation methods. (author). 39 refs.; 1 fig.; 5 tabs

  6. Preliminary results of the alpha particle registration intercomparison ALRIT

    International Nuclear Information System (INIS)

    Paretzke, H.G.

    1976-01-01

    In view of the widespread interest in alpha particle registration with solid state nuclear track detectors, an international intercomparison of such measurements has been arranged. Sixteen sets of fourteen detectors each were sent to GSF-Neuherberg, there irradiated carefully with different alpha particle fields, and then returned for evaluation. Fourteen irradiation runs were made for each set simulating seven different irradiation situations commonly encountered in practical applications. The preliminary results of this intercomparison reported in this paper are based on the results of eight sets. They show good agreement with respect to the determination of track densities in the case of vertical incident alpha particles. Also the results obtained for determination of particle energies and angle of incidence in most cases were rather accurate. However, apparently it is still rather difficult to determine accurately and precisely the specific activity of alpha emitters on a thick filter positioned at some distance, i.e. for the case of 2π-incidence and a broad energy spectrum. (orig.) [de

  7. DOE radiological calibrations intercomparison program: Results of fiscal year 1986

    International Nuclear Information System (INIS)

    Cummings, F.M.; Roberson, P.L.; McDonald, J.C.

    1987-05-01

    The Department of Energy Radiological Calibration Intercomparison Program was initiated in January 1986, under the research portion of the DOE Laboratory Accreditation Program. The program operates via the exchange of transfer standards, consisting of instrument sets and standard secondary beta sources. There are two instrument sets and the scheduled use has been staggered such that one set is available for use during each month. One set of secondary standard beta sources is available for use bimonthly. During the 1986 fiscal year, five laboratories used the instrument sets and three laboratories used the beta source set. Results were reported for all the measurements. The average and one standard deviation of the ratios of participant results to Pacific Northwest Laboratory calibration values were 1.12 +- 0.17 for gamma measurements. Those ratios for the gamma measurements varied from 0.98 to 3.06. The larger differences of results from measurements performed at two facilities were directly attributable to unfamiliarity with the intercomparison instruments. The average and one standard deviation of the ratios of participant results to PNL calibration values obtained using the secondary 90 Sr beta source was 1.02 +- 0.05, which is well within measurement uncertainties. The one participant who performed measurements using 147 Pm and 204 Tl sources obtained ratios of 0.68 and 1.11, respectively. No measurements were performed using neutron or x-ray sources

  8. Intercomparison 2003 for Radon measurement services at PSI

    CERN Document Server

    Butterweck, G

    2003-01-01

    Twelve radon measurement services participated in the 2003 Radon Intercomparison Exercise performed at the Reference Laboratory for Radon Gas Activity Concentration Measurements at Paul Scherrer Institut (PSI) during March 13th to 24th, 2003. Ten of these laboratories were approved by the Swiss Federal Office of Public Health and their participation in the intercomparison exercise was a requirement to warrant quality of measurement. Radon gas detectors (etched-track and electret ionisation chambers) and instruments (ionisation chambers and electrostatic precipitation) were exposed in the PSI Radon Chamber in a reference atmosphere with an average radon gas concentration of 1950 Bqm sup - sup 3 leading to a radon gas exposure of 517 kBqhm sup - sup 3. Additional five electret-detectors of an approved measuring service were purchased by the Swiss Federal Office of Public Health for a spot check. Two of these were exposed as described above, two had an exposure of 247 kBqhm sup - sup 3 at an average radon concen...

  9. In-situ gammaspectrometry intercomparison exercise in Salzburg/Austria

    International Nuclear Information System (INIS)

    Steger, F.; Lovranich, E.; Lettner, H.; Andrasi, A.

    1996-01-01

    In-situ gamma-spectrometry has become a useful method of assessing the nuclide concentrations of man-made and natural gamma-emitters in the soil. For the quality assurance of the measurements, periodically conducted intercomparison exercises are essential. Therefore exercises were organized in different European countries since 1990, the last one was conducted in Salzburg /Austria in September 1994. The participation of 24 measurement-teams from all over Europe emphasizes the importance of the intercomparison. Salzburg was selected because the Province of Salzburg /Austria was among the most heavily contaminated regions outside the former USSR by the Chernobyl fallout. Two different typical sites were selected for the measurements: Site 1 was inside the urban area of Salzburg on intensively used grassland which had not been tilled since the deposition of the fallout. This site is representative for intensively used agricultural regions in the Province of Salzburg. Site 2 was in the mountainous regions of the Hohe Tauern at an elevated altitude of 1600 m, representing the agricultural soil- and contamination conditions of the Alpine regions in the Tauern. The two sites differ significantly in terms of soil characteristics, a crucial parameter for the evaluation of in-situ gamma-spectra. The participants used different approaches for the evaluation of the gamma-spectra in terms of considering the depth distribution. In the paper the results from the 24 European teams are presented. (author)

  10. Extremity ring dosimetry intercomparison in reference and workplace fields

    International Nuclear Information System (INIS)

    Ginjaume, M.; Carinou, E.; Donadille, L.; Jankowski, J.; Rimpler, A.; Sans Merce, M.; Vanhavere, F.; Denoziere, M.; Daures, J.; Bordy, J. M.; Itie, C.; Covens, P.

    2008-01-01

    An intercomparison of ring dosemeters has been organised with the aim of assessing the technical capabilities of available extremity dosemeters and focusing on their performance at clinical workplaces with potentially high extremity doses. Twenty-four services from 16 countries participated in the intercomparison. The dosemeters were exposed to reference photon ( 137 Cs) and beta ( 147 Pm, 85 Kr and 90 Sr/ 90 Y) fields together with fields representing realistic exposure situations in interventional radiology (direct and scattered radiation) and nuclear medicine ( 99m Tc and 18 F). It has been found that most dosemeters provided satisfactory measurements of H p (0.07) for photon radiation, both in reference and realistic fields. However, only four dosemeters fulfilled the established requirements for all radiation qualities. The main difficulties were found for the measurement of low-energy beta radiation. Finally, the results also showed a general under-response of detectors to 18 F, which was attributed to the difficulties of the dosimetric systems to measure the positron contribution to the dose. (authors)

  11. Intercomparison test of various aerosol measurement techniques

    International Nuclear Information System (INIS)

    Cherdron, W.; Hassa, C.; Jordan, S.

    1984-01-01

    At the suggestion of the CONT group (Containment Loading and Response), which is a subgroup of the Safety Working Group of the Fast Reactor Coordinating Committee, a group of experts undertook a comparison of the techniques of sodium aerosol measurement used in various laboratories in the EC. The following laboratories took part in the exercise: CEN-Mol (Belgium), CEA-Cadarache (France), CEA-Fontenay-aux-Roses (France), KfK-Karlsruhe (Federal Republic of Germany), ENEA-Bologna (Italy), and UKAEA-Winfrith (United Kingdom). The objective of the aerosol measurement workshop was to assess the applicability and reliability of specific aerosol measuring instruments. Measurements performed with equipment from the participating laboratories were evaluated using a standard procedure. This enabled an estimate of the accuracy of the experimental data to be provided for the verification of aerosol codes. Thus these results can be used as input for the physical modelling of aerosol behaviour, and the work reported here is a contribution to the definition of the radioactive source term for severe accidents in LMFBRs. The aerosol experts participating in the exercise agreed to concentrate on the techniques of measuring aerosol particle size distributions. The tests were performed at the FAUNA test facility using the aerosol loop. A sodium spray fire, which provides a continuous aerosol source of variable concentration, was produced under open-loop conditions in this facility. Although the primary objective of the workshop was to determine the particle size distributions of the aerosols, measurements of the sodium mass concentration were also made

  12. Luminescence dating of architectural ceramics from an early medieval abbey: The St Philbert Intercomparison (Loire Atlantique, France)

    Energy Technology Data Exchange (ETDEWEB)

    Guibert, P. [CNRS-Universite Bordeaux, UMR 5060, IRAMAT-CRP2A, Maison de l' Archeologie, F-33607 Pessac (France)], E-mail: guibert@u-bordeaux3.fr; Bailiff, I.K. [University of Durham, Department of Archaeology, Luminescence Laboratory, South Road, Durham, DH1 3LE (United Kingdom); Blain, S. [CNRS-Universite Bordeaux, UMR 5060, IRAMAT-CRP2A, Maison de l' Archeologie, F-33607 Pessac (France); University of Durham, Department of Archaeology, Luminescence Laboratory, South Road, Durham, DH1 3LE (United Kingdom); Gueli, A.M. [LDL and BBCC, Department of Physics and Astronomy, Centro Siciliano di Fisica Nucleare e di Struttura della Materia, Universita di Catania and INFN Sezione di Catania, via Santa Sofia 64, I-95123 Catania (Italy); Martini, M.; Sibilia, E. [INFN, CNR-INFN and CUDAM, Univ. Milano Bicocca, U5, via R. Cozzi 53, I-20125 Milano (Italy); Stella, G.; Troja, S.O. [LDL and BBCC, Department of Physics and Astronomy, Centro Siciliano di Fisica Nucleare e di Struttura della Materia, Universita di Catania and INFN Sezione di Catania, via Santa Sofia 64, I-95123 Catania (Italy)

    2009-05-15

    An experimental intercomparison was performed with brick samples from an early medieval building in the west of France, the St-Philbert-de-Grandlieu abbey. A potentially complex set of microdosimetric problems emerged from characterisation measurements, providing a robust test of the routine procedures used by each laboratory. The dating results obtained using quartz coarse grains and fine grain samples span over a large period of time, exhibiting overdispersion, and where systematic deviations appear between quartz and fine grain chronologies. Factors causing such scatter are analysed in detail, including internal radioactivity of quartz grains, millimetre-scale heterogeneity in the fabric, and the observation and modelling of fading behaviour of fine grain minerals.

  13. Luminescence dating of architectural ceramics from an early medieval abbey: The St Philbert Intercomparison (Loire Atlantique, France)

    International Nuclear Information System (INIS)

    Guibert, P.; Bailiff, I.K.; Blain, S.; Gueli, A.M.; Martini, M.; Sibilia, E.; Stella, G.; Troja, S.O.

    2009-01-01

    An experimental intercomparison was performed with brick samples from an early medieval building in the west of France, the St-Philbert-de-Grandlieu abbey. A potentially complex set of microdosimetric problems emerged from characterisation measurements, providing a robust test of the routine procedures used by each laboratory. The dating results obtained using quartz coarse grains and fine grain samples span over a large period of time, exhibiting overdispersion, and where systematic deviations appear between quartz and fine grain chronologies. Factors causing such scatter are analysed in detail, including internal radioactivity of quartz grains, millimetre-scale heterogeneity in the fabric, and the observation and modelling of fading behaviour of fine grain minerals.

  14. A dosimetric intercomparison of brachytherapy facilities in Ireland, Scotland and the North of England

    International Nuclear Information System (INIS)

    Heeney, Conor; McClean, Brendan; Kelly, Colin

    2005-01-01

    Background and purpose: A dosimetric intercomparison of brachytherapy remote afterloading units in Ireland, Scotland and the North of England has been carried out involving 9 radiotherapy centres, and sampling 5 HDR and 6 LDR units. Materials and methods: Absolute calibrations have been performed in air on both HDR and LDR sources. The results are expressed in terms of a ratio of local to calibrated value. Frequency distributions were obtained for the multi-source LDR units by individually measuring each source. Using these distributions the effect of non-uniform source strength on the dose rate at Manchester point A was assessed for a typical clinical brachytherapy insertion for carcinoma of the cervix. Both frequency and dose rate distribution curves were modeled using normal statistics and characterised in terms of the mean (μ) and standard deviation (σ). Results: Evaluation of the HDR units indicated a mean ratio of 1.008 (±0.01) while for LDR the mean ratio was 0.997 (±0.02). The LDR frequency distributions demonstrated a variation of σ values extending from 1.4 to 3.0% of μ. It was shown that this non-uniformity in source strength introduced an uncertainty in the treatment planning process of between 0.8 and 1.8% when compared to the assumption of uniform source strength. Conclusions: The results of this intercomparison indicate dosimetric consistency between centres for both LDR and HDR units. The distribution of LDR source strengths were within expected limits and the resultant dose rate distributions were considered clinically acceptable

  15. Psacoin level S intercomparison: An International code intercomparison exercise on a hypothetical safety assessment case study for radioactive waste disposal systems

    International Nuclear Information System (INIS)

    1993-06-01

    This report documents the Level S exercise of the Probabilistic System Assessment Group (PSAG). Level S is the fifth in a series of Probabilistic Code Intercomparison (PSACOIN) exercises designed to contribute to the verification of probabilistic codes and methodologies that may be used in assessing the safety of radioactive waste disposal systems and concepts. The focus of the Level S exercise lies on sensitivity analysis. Given a common data set of model output and input values the participants were asked to identify both the underlying model's most important parameters (deterministic sensitivity analysis) and the link between the distributions of the input and output values (distribution sensitivity analysis). Agreement was generally found where it was expected and the exercise has achieved its objectives in acting as a focus for testing and discussing sensitivity analysis issues. Among the outstanding issues that have been identified are: (i) that techniques for distribution sensitivity analysis are needed that avoid the problem of statistical noise; (ii) that further investigations are warranted on the most appropriate way of handling large numbers of effectively zero results generated by Monte Carlo sampling; and (iii) that methods need to be developed for demonstrating that the results of sensitivity analysis are indeed correct

  16. Proceedings: special panel on geothermal model intercomparison study

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-17

    Separate abstracts were prepared for five papers. Two papers were abstracted previously for EDB. Five panel responses to the project, three workshop session summaries, and conclusions drawn are also included in this report. (MHR)

  17. Last interglacial temperature evolution – a model inter-comparison

    NARCIS (Netherlands)

    Bakker, P.; Stone, E.J.; Charbit, S.; Gröger, M.; Krebs-Kanzow, U.; Ritz, S.P.; Varma, V.; Khon, S.; Lunt, D.J.; Mikolajewicz, U.; Prange, M.; Renssen, H.; Schneider, B.; Schulz, M.

    2013-01-01

    There is a growing number of proxy-based reconstructions detailing the climatic changes that occurred during the last interglacial period (LIG). This period is of special interest, because large parts of the globe were characterized by a warmer-than-present-day climate, making this period an

  18. Intercomparison of Martian Lower Atmosphere Simulated Using Different Planetary Boundary Layer Parameterization Schemes

    Science.gov (United States)

    Natarajan, Murali; Fairlie, T. Duncan; Dwyer Cianciolo, Alicia; Smith, Michael D.

    2015-01-01

    We use the mesoscale modeling capability of Mars Weather Research and Forecasting (MarsWRF) model to study the sensitivity of the simulated Martian lower atmosphere to differences in the parameterization of the planetary boundary layer (PBL). Characterization of the Martian atmosphere and realistic representation of processes such as mixing of tracers like dust depend on how well the model reproduces the evolution of the PBL structure. MarsWRF is based on the NCAR WRF model and it retains some of the PBL schemes available in the earth version. Published studies have examined the performance of different PBL schemes in NCAR WRF with the help of observations. Currently such assessments are not feasible for Martian atmospheric models due to lack of observations. It is of interest though to study the sensitivity of the model to PBL parameterization. Typically, for standard Martian atmospheric simulations, we have used the Medium Range Forecast (MRF) PBL scheme, which considers a correction term to the vertical gradients to incorporate nonlocal effects. For this study, we have also used two other parameterizations, a non-local closure scheme called Yonsei University (YSU) PBL scheme and a turbulent kinetic energy closure scheme called Mellor- Yamada-Janjic (MYJ) PBL scheme. We will present intercomparisons of the near surface temperature profiles, boundary layer heights, and wind obtained from the different simulations. We plan to use available temperature observations from Mini TES instrument onboard the rovers Spirit and Opportunity in evaluating the model results.

  19. Outline of the 1996-1998 IAEA co-ordinated research project on intercomparison for individual monitoring of external exposure from photon radiation

    International Nuclear Information System (INIS)

    Boehm, J.; Gustafsson, M.; Ouvrard, R.

    1999-01-01

    The outline of the IAEA Co-ordinated Research Project 1996-1998 on intercomparison for individual monitoring is described. The intercomparison focused on IAEA Member States in Eastern Europe and was based on the operational quantity personal dose equivalent, H p (10). The three phases of the intercomparison were: the preparatory phase including a workshop, the 'type-test' intercomparison, and the 'simulated workplace field' intercomparison. Details of the phases are given. (author)

  20. Intercomparison of personal dose equivalent measurements by active personal dosimeters. Final report of a joint IAEA-EURADOS project

    International Nuclear Information System (INIS)

    2007-11-01

    Active personal dosimeters (APD) are widely used in many countries, i.e. in the medical field and as operational dosimeters in nuclear power plants. Their use as legal dosimeters is already established in a few countries, and will increase in the near future. In the majority of countries, APDs have not undergone accreditation programmes or intercomparisons. In 2001, an EURADOS (European Radiation Dosimetry Group) Working Group on harmonization of individual monitoring was formed, funded by the European Commission, in the fifth framework programme, and by the participating institutes. The work addressed four issues; inter alia also an inventory of new developments in individual monitoring with an emphasis on the possibilities and performance of active (electronic) dosimeters for both photon/beta and neutron dosimetry. Within the work on this issue, a catalogue of the most extensively used active personal dosimeters (APDs) suitable for individual monitoring was made. On the basis of the knowledge gained in this activity, the organization of an international intercomparison, which would address APDs, was considered of great value to the dosimetric community. The IAEA in cooperation with EURADOS organized such an intercomparison in which most of the testing criteria as described in two internationally accepted standards (IEC61526 and IEC61283) were used. Additionally, simulated workplace fields were used for testing the APD reactions to pulsed X ray fields and mixed gamma/X ray fields. This is the first time that results of comparisons of such types are published, which is of great importance for APD end users in medical diagnostic and surgery X ray applications. Nine suppliers from six countries in Europe and the USA participated in the intercomparison with 13 different models. One of the models was a special design for extremity dose measurements. Irradiations and readout was done by two accredited calibration laboratories in Belgium and France and the French

  1. Lessons learnt from participation in international inter-comparison exercise for environmental radioactivity measurement

    International Nuclear Information System (INIS)

    Jha, S.K.; Pulhani, Vandana; Sartandel, Sangeeta

    2016-06-01

    Environmental Radioactivity Measurement Section of Health Physics Division is regularly carrying out surveillance of the radioactivity concentration in the environment. The laboratory participates in the inter-comparison exercises conducted by various international agencies for quality assurance and quality control of analytical estimations. This report summarizes the results of the analysis of radioactivity in environmental matrices of the inter-comparison exercises. The participation in inter-comparison exercises has demonstrated competence in radionuclide identification and estimations, equivalence with the results of other participating laboratories, validated adopted analytical methods, introduced traceability to measurement etc. at national and international level. (author)

  2. Nuclear accident dosimetry, Report on the Third IAEA intercomparison experiment at Vinca, Yugoslavia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1977-03-15

    The objective of this report is to present the results of the third IAEA intercomparison experiment held at the Boris Kidric Institute, Vinca, in May 1973. These experiments were a part of multi laboratory intercomparison programme sponsored by the IAEA for evaluation of nuclear accident dosimetry systems that ought to provide adequate information in the event of criticality accidents. This report deals with the data concerning the Third intercomparison experiments in which the RB reactor at Vinca was used as a source of mixed radiation.

  3. International intercomparison on the neutron flux density spectrum just before the REAL-80 project

    International Nuclear Information System (INIS)

    Ertek, C.

    1981-06-01

    This work briefly presents the results of the international intercomparison on the neutron flux density spectrum just before the REAL-80 intercomparison project. Some of the results of this intercomparison with a smaller number of laboratories will be also reflected in the REAL-80 project, therefore, it has some significant issues. This work is performed within the IAEA programme on standardization of reactor radiation measurements, one of the important objectives of which is the assistance of laboratories in Member States to implement or intercompare the multiple foil activation techniques for different neutron field measurements

  4. Report on intercomparison exercise SR-54. Determination of impurities in U3O8

    International Nuclear Information System (INIS)

    Doubek, N.; Bagliano, G.; Deron, S.

    1984-04-01

    The report presents results of a laboratory intercomparison of impurities in U 3 O 8 sample organized by the IAEA's Analytical Quality Control Service. Twelve laboratories in 11 countries sent their results. The framework of the intercomparison was therefore conceived mainly as a ''mean'' to laboratories dealing with analysis of impurities in uranium samples to check the reliability of their results. The evaluation was based on 97 laboratory means obtained with emission spectroscopy, atomic absorption techniques and neutron activation analysis. The concentration of three elements could be certified as a result of this intercomparison; informational values could be established for an additional six elements

  5. Intercomparison of radionuclide measurements in marine sediment sample IAEA-135

    International Nuclear Information System (INIS)

    Ballestra, S.; Gastaud, J.; Lopez, J.J.; Parsi, P.; Vas, D.

    1993-08-01

    The results of an intercomparison exercise on a marine sediment from Irish Sea, IAEA-135, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 151 laboratories representing 51 countries have been evaluated. The following are the recommended values, with confidence intervals, for 40 K, 60 Co, 134 Cs, 137 Cs, 154 Eu, 155 Eu, 226 Ra, 228 Ra, 232 Th, 238 Pu, 239+240 Pu (Reference date: 1 January 1992). Information values for 57 Co, 90 Sr, 106 Ru, 125 Sb, 210 Pb, 210 Po, 228 Th, 230 Th, 234 U, 235 U, 238 U and 241 Am are also reported. All values are expressed in Bq kg -1 dry weight. (author)

  6. Intercomparison of radionuclide measurements in marine sediment sample IAEA-367

    Energy Technology Data Exchange (ETDEWEB)

    Ballestra, S; Lopez, J J; Gastaud, J; Vas, D; Noshkin, V

    1991-08-01

    The results of an intercomparison exercise on a Pacific Ocean sediment sample, IAEA-367, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 81 laboratories representing 37 countries have been evaluated. The following are the recommended values, with confidence intervals, for {sup 60}Co, {sup 90}Sr, {sup 137}Cs, {sup 239+240}Pu (Reference date: 1 January 1990). Information values for {sup 155}Eu, {sup 238}Pu, {sup 241}Am, and {sup 241}Pu are reported. Information values for the following natural radionuclides {sup 40}K, {sup 226}Ra, {sup 228}Th, {sup 230}Th, {sup 234}U, {sup 235}U and {sup 238}U are also reported. (author)

  7. Intercomparison of radionuclide measurements in marine sediment sample IAEA-135

    Energy Technology Data Exchange (ETDEWEB)

    Ballestra, S; Gastaud, J; Lopez, J J; Parsi, P; Vas, D

    1993-08-01

    The results of an intercomparison exercise on a marine sediment from Irish Sea, IAEA-135, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 151 laboratories representing 51 countries have been evaluated. The following are the recommended values, with confidence intervals, for {sup 40}K, {sup 60}Co, {sup 134}Cs, {sup 137}Cs, {sup 154}Eu, {sup 155}Eu, {sup 226}Ra, {sup 228}Ra, {sup 232}Th,{sup 238}Pu, {sup 239+240}Pu (Reference date: 1 January 1992). Information values for {sup 57}Co, {sup 90}Sr, {sup 106}Ru, {sup 125}Sb, {sup 210}Pb, {sup 210}Po, {sup 228}Th, {sup 230}Th, {sup 234}U, {sup 235}U, {sup 238}U and {sup 241}Am are also reported. All values are expressed in Bq kg{sup -1} dry weight. (author)

  8. Intercomparison of radionuclide measurements in marine sediment sample IAEA-368

    Energy Technology Data Exchange (ETDEWEB)

    Ballestra, S; Lopez, J J; Gastaud, J; Parsi, P; Vas, D; Noshkin, V

    1991-08-01

    The results of an intercomparison exercise on a Pacific Ocean sediment sample, IAEA-368, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 89 laboratories representing 37 countries have been evaluated. The following are the recommended values, with confidence intervals, for {sup 60}Co, {sup 155}Eu, {sup 210}7Pb, {sup 226}Ra, {sup 238}U, {sup 238}Pu and{sup 239+240}Pu (Reference date: 1 January 1990). Information values for {sup 40}K, {sup 90}Sr, {sup 137}Cs, {sup 228}Th, {sup 230}Th, {sup 232}Th, {sup 234}U, {sup 235}U and {sup 241}Am are also reported. (author)

  9. Austrian WBC intercomparison by means of a BOMAB phantom

    Energy Technology Data Exchange (ETDEWEB)

    Castellani, C.M.; Battisti, P.; Tarroni [ENEA, Centro Ricerche Ezio Clementel, Bologna (Italy). Dipt. Ambiente; Edelmeier, R. [Bundesamt fuer Eich- und Vermessungswesen, Wien (Austria)

    1998-07-01

    The paper discusses the results obtained in the intercomparison between the Austrian Institute for Legal Metrology and the ENEA (National Agency for New Technology, Energy and the Environment) Institute for Radiation Protection, which gave a BOMAB phantom. Values related to potassium content and MBA (minimum detectable activity) for each identified nuclide are also discussed. [Italian] L'Istituto Austriaco di Metrologia Legale ha organizzato l'interconfronto usando un fantoccio gelificato di tipo BOMAB fornito dall'Istituto di Radioprotezione dell'ENEA nel periodo marzo-giugno 1996. Vengono riportati i risultati ottenuti relativi al contenuto di potassio e all'attivita' minima rilevabile (MDA) per ogni nuclide identificato.

  10. Intercomparison of different instruments for measuring radon concentration in air

    International Nuclear Information System (INIS)

    Shimo, Michikuni; Iida, Takao

    1990-01-01

    An intercomparison of different instruments for measurement of radon concentration was carried out. The instruments include an ionization chamber, the charcoal-trap method, a flow-type ionization chamber (pulse-counting method), a two-filter method, an electrostatic collection method and a passive integration radon monitor. All instruments except for the passive radon monitor have been calibrated independently. Measurements were performed over a concentration range from about 3.5 Bq·m -3 (in outdoor air) to 110 Bq·m -3 (in indoor air). The results obtained by these techniques, except the two-filter technique, are comparable. Radon daughter concentration measured using a filter-sampling method was about 52% of radon concentration. (author)

  11. Intercomparison of different instruments that measure radon concentration in air

    International Nuclear Information System (INIS)

    Shimo, M.; Iida, T.; Ikebe, Y.

    1987-01-01

    An intercomparison of different instruments for measurement of radon concentration was carried out. The instruments include an ionization chamber, the charcoal-trap technique, a flow-type ionization chamber (pulse-counting technique), a two-filter method, an electrostatic collection method and a passive integrating radon monitor. All instruments except for the passive radon monitor have been calibrated independently. Measurements were performed over a concentration range from about 3.5 Bq/m/sup 3/ (in outdoor air) to 110 Bq/m/sup 3/ (in indoor air). The results obtained from these techniques, except the two-filter technique, are comparable. Radon daughter concentration measured using a filter-sampling technique was about 52% of radon concentrations

  12. Radiation quality assurance intercomparison studies 1974--1975

    International Nuclear Information System (INIS)

    1975-10-01

    The Quality Assurance Branch of the Monitoring Systems Research and Development Division at the U.S. Environmental Protection Agency's Environmental Monitoring and Support Laboratory-Las Vegas prepares and distributes calibrated low-level radioactive solutions to Federal, State, and private laboratories involved in environmental radiation monitoring and surveillance. These solutions are used for both the calibration of counting instruments and chemical yield determinations. Since the laboratories using these samples must have confidence in their accuracy, the Quality Assurance Branch has instituted intercomparison studies with the National Bureau of Standards and with the Energy Research and Development Administration Health and Service Laboratory. The results of the studies conducted during 1974 and 1975 are described

  13. Intercomparison of radionuclide measurements on marine sediment sample IAEA-300

    International Nuclear Information System (INIS)

    Ballestra, S.; Gastaud, J.; Lopez, J.J.; Parsi, P.; Vas, D.

    1994-09-01

    The results of an intercomparison exercise on a sediment from Baltic Sea, IAEA-300, designed for the determination of artificial and natural radionuclides' levels, are reported. The data from 159 laboratories representing 51 countries have been evaluated. The following are the recommended values, with confidence intervals, 40 K, 60 Co, 125 Sb, 134 Cs, 137 Cs, 155 Eu, 210 Pb, 210 Po, 228 Ra, 234 U, 238 U, 239+240 Pu and 241 Am. Information values for 54 Mn, 90 Sr, 226 Ra, 228 Th, 230 Th, 232 Th, 235 U and 238 Pu are also reported. All values are given on the reference date of 1 January 1993 and expressed in Bq kg -1 dry weight. (author)

  14. Report on the intercomparison run IAEA-156 radionuclides in clover

    International Nuclear Information System (INIS)

    Strachnov, V.; Valkovic, V.; Dekner, R.

    1991-01-01

    This report contains the results of the intercomparison IAEA-156 on the determination of radionuclides in clover. Initially participants were requested to determine the levels of 134 Cs, 137 Cs, 40 K, 90 Sr and invited to provide data for other radionuclides. The participants included 46 laboratories located in 25 countries, and statistical evaluation of their data yield recommended values for these four radionuclides. Additional radionuclides reported were 210 Pb, 239 Pu and 125 Sb; however, insufficient data exists to statistically determine recommended values for these radionuclides. The following are the recommended values, with confidence intervals, for the most frequently measured radionuclides (reference date: 1 August 1986): 134 Cs 132.1 Bq/kg (126.4-137.7); 137 Cs 264 Bq/kg (254-274); 40 K 657 Bq/kg (637-676); 90 Sr 14.8 Bq/kg (13.4-16.3). Figs and tabs

  15. Intercomparison test on hearing protectors (EU, VG4)

    DEFF Research Database (Denmark)

    Poulsen, Torben

    1997-01-01

    Real Ear Attenuation at Threshold (REAT) was measured on 16 human test subjects in accordance with EN 24869-1. Insertion loss for the individual cups was determined in accordance with EN 352-1, paragraph 7.11-7.11.3.3. Both the REAT and the insertion loss measurements were performed in an approxi......Real Ear Attenuation at Threshold (REAT) was measured on 16 human test subjects in accordance with EN 24869-1. Insertion loss for the individual cups was determined in accordance with EN 352-1, paragraph 7.11-7.11.3.3. Both the REAT and the insertion loss measurements were performed...... in an approximated diffuse field. The field was established in a semi reverberant room with uncorrelated one-third octave bands of noise from two loudspeakers. The measurements are part of a European intercomparison project 'Sound attenuation in accordance with EN-24869-1'....

  16. International intercomparison of environmental dosimeters under field and laboratory conditions

    International Nuclear Information System (INIS)

    Gesell, T.F.; de Planque Burke, G.; Becker, K.

    1975-04-01

    Based on the results of a pilot study at ORNL in 1973, a more comprehensive international intercomparison of integrating dosimeters for the assessment of external penetrating environmental radiation fields was carried out. Forty-one laboratories from eleven countries participated in this study. A total of 56 sets of six detectors each were mailed to and from Houston, Texas, where they were exposed for three months (July to September 1974) as follows: two in an unprotected space out-of-doors 1 m above ground; two in an air-conditioned shielded area with a known, low exposure rate; and two with the second group, but with an additional exposure to 30 mR. Evaluation of the dosimeters provides information on the calibration precision, the accuracy of field measurement, and transit exposure. Results are discussed. (U.S.)

  17. Ground-based intercomparison of two isoprene measurement techniques

    Directory of Open Access Journals (Sweden)

    E. Leibrock

    2003-01-01

    Full Text Available An informal intercomparison of two isoprene (C5H8 measurement techniques was carried out during Fall of 1998 at a field site located approximately 3 km west of Boulder, Colorado, USA. A new chemical ionization mass spectrometric technique (CIMS was compared to a well-established gas chromatographic technique (GC. The CIMS technique utilized benzene cation chemistry to ionize isoprene. The isoprene levels measured by the CIMS were often larger than those obtained with the GC. The results indicate that the CIMS technique suffered from an anthropogenic interference associated with air masses from the Denver, CO metropolitan area as well as an additional interference occurring in clean conditions. However, the CIMS technique is also demonstrated to be sensitive and fast. Especially after introduction of a tandem mass spectrometric technique, it is therefore a candidate for isoprene measurements in remote environments near isoprene sources.

  18. SSDL Argentina: Dosimetric intercomparison programme for cobalt 60 therapy units

    Energy Technology Data Exchange (ETDEWEB)

    Saravi, M; Papadopulos, S; Mugliaroli, H [Comision Nacional de Energia Atomica, Buenos Aires (Argentina)

    1996-08-01

    Thermoluminescence dosimeters (TLD) are widely used to verify absorbed dose delivered from radiation therapy beams. The Secondary Standard Dosimetry Laboratory (SSDL) of Argentina uses TLD for its mailed dose intercomparison programme for cobalt 60 radiation therapy units. Results obtained since 1978 as well as causes of dose discrepancies greater than 5% are analyzed. Results of the external quality control performed by the IAEA for this programme indicate that the dose evaluated by the SSDL TLD service for the participating centers is about 1% lower than that evaluated by the IAEA TLD service. This deviation is accepted taking on account that a {+-} 2% dose uncertainty for TLD dosimetry is reasonable. (author). 5 refs, 5 figs, 2 tabs.

  19. Intercomparison of radionuclide measurements on marine sediment sample IAEA-300

    Energy Technology Data Exchange (ETDEWEB)

    Ballestra, S; Gastaud, J; Lopez, J J; Parsi, P; Vas, D

    1994-09-01

    The results of an intercomparison exercise on a sediment from Baltic Sea, IAEA-300, designed for the determination of artificial and natural radionuclides' levels, are reported. The data from 159 laboratories representing 51 countries have been evaluated. The following are the recommended values, with confidence intervals, {sup 40}K, {sup 60}Co, {sup 125}Sb, {sup 134}Cs, {sup 137}Cs, {sup 155}Eu, {sup 210}Pb, {sup 210}Po, {sup 228}Ra, {sup 234}U, {sup 238}U, {sup 239+240}Pu and {sup 241}Am. Information values for {sup 54}Mn, {sup 90}Sr, {sup 226}Ra, {sup 228}Th, {sup 230}Th, {sup 232}Th, {sup 235}U and {sup 238}Pu are also reported. All values are given on the reference date of 1 January 1993 and expressed in Bq kg{sup -1} dry weight. (author)

  20. Precision intercomparison of beam current monitors at CEBAF

    International Nuclear Information System (INIS)

    Kazimi, R.; Dunham, B.; Krafft, G.A.; Legg, R.; Liang, C.; Sinclair, C.; Mamosser, J.

    1995-01-01

    The CEBAF accelerator delivers a CW electron beam at fundamental 1497 MHz, with average beam current up to 200 μA. Accurate, stable nonintercepting beam current monitors are required for: setup/control, monitoring of beam current and beam losses for machine protection and personnel safety, and providing beam current information to experimental users. Fundamental frequency stainless steel RF cavities have been chosen for these beam current monitors. This paper reports on precision intercomparison between two such RF cavities, an Unser monitor, and two Faraday cups, all located in the injector area. At the low beam energy in the injector, it is straightforward to verify the high efficiency of the Faraday cups, and the Unser monitor included a wire through it to permit an absolute calibration. The cavity intensity monitors have proven capable of stable, high precision monitoring of the beam current

  1. Low-Level Waste Drum Assay Intercomparison Study

    International Nuclear Information System (INIS)

    Greutzmacher, K.; Kuzminski, J.; Myers, S. C.

    2003-01-01

    Nuclear waste assay is an integral element of programs such as safeguards, waste management, and waste disposal. The majority of nuclear waste is packaged in drums and analyzed by various nondestructive assay (NDA) techniques to identify and quantify the radioactive content. Due to various regulations and the public interest in nuclear issues, the analytical results are required to be of high quality and supported by a rigorous Quality Assurance (QA) program. A valuable QA tool is an intercomparison program in which a known sample is analyzed by a number of different facilities. While transuranic waste (TRU) certified NDA teams are evaluated through the Performance Demonstration Program (PDP), low-level waste (LLW) assay specialists have not been afforded a similar opportunity. NDA specialists from throughout the DOE complex were invited to participate in this voluntary drum assay intercomparison study that was organized and facilitated by the Solid Waste Operations and the Safeguards Science and Technology groups at the Los Alamos National Laboratory and by Eberline Services. Each participating NDA team performed six replicate blind measurements of two 55-gallon drums with relatively low-density matrices (a 19.1 kg shredded paper matrix and a 54.4 kg mixed metal, rubber, paper and plastic matrix). This paper presents the results from this study, with an emphasis on discussing the lessons learned as well as desirable follow up programs for the future. The results will discuss the accuracy and precision of the replicate measurements for each NDA team as well as any issues that arose during the effort

  2. IAEA/ WHO TLD postal dose intercomparison results in Bangladesh

    International Nuclear Information System (INIS)

    Mollah, A.S.; Bhuiyan, N.U.; Rahman, S.

    2001-01-01

    Full text: For the accurate delivery of prescribed dose to the patients, high precision and accuracy in radiation dosimetry is required. The hospital/medical physicist is responsible for the accurate delivery of whole planned radiation doses to the patients prescribed by the radio therapist. The proper delivery of radiation doses depends upon the accurate output measurements of doses from the therapy machines. In Bangladesh, only six 60 Co units and five deep therapy machines are in use. Some more are expected to be installed soon. Still in 2001, none of the Government radiotherapy centers in Bangladesh was properly equipped with medical physicists as well as radiotherapy dosimetry equipment. Bangladesh Atomic Energy Commission (BAEC) is responsible for radiation safety in Bangladesh and BAEC has assigned Secondary Standard Dosimetry Laboratory (SSDL) of Bangladesh for providing dosimetry calibration to all radiotherapy centers in Bangladesh. The output measurements of therapy machines are performed once in a year by SSDL and the results are compared by participating in the annual TLD postal dose intercomparison program organized by IAEA/WHO SSDL Network. The absorbed dose to water is determined using IAEA dosimetry protocol (TRS 277 and 381) and water phantom of size 30 x 30 x 30 cm 3 , The measurements of SSDL are traceable to NPL of UK. The accuracy achieved in SSDL, Bangladesh has been found better than ± 3.5%, which is within the prescribed limit of dosimetry standard of IAEA. The methodology of output dose measurements in different radiotherapy centers in Bangladesh is described along with the IAEA/WHO intercomparison results

  3. Intercomparison of ozone measurements between Lidar and ECC-sondes

    Energy Technology Data Exchange (ETDEWEB)

    Grabbe, G.C. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Boesenberg, J. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Dier, H. [Meteorologisches Obs., Lindenberg (Germany); Goersdorf, U. [Meteorologisches Obs., Lindenberg (Germany); Matthias, V. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Peters, G. [Meteorologisches Obs., Lindenberg (Germany); Schaberl, T. [Hamburg Univ. (Germany). Meteorologisches Inst.; Senff, C. [Hamburg Univ. (Germany). Meteorologisches Inst.

    1996-02-01

    An intercomparison experiment for measurements of ozone vertical profiles in the lower troposphere was performed using a ground-based ozone DIAL (DIfferential Absorption Lidar) and ECC-sondes (Electrochemical Concentration Cell) attached to tethered as well as free flying balloons, which took place in June of 1994. The tethered balloon was used for ozone soundings in the planetary boundary layer up to an altitude of 500 m, while in the free troposphere free flying balloons were used. For the time series of up to 90 min obtained with the tethersondes both averages and standard deviations are compared. The mean difference for all measurements amounted to 3.5 {mu}g/m{sup 3} only, corresponding to 3.5%. For the instantaneous profiles compared to the free flying sondes the differences were only marginally larger, with a mean value of 3.6 {mu}g/m{sup 3} corresponding to 4.1%. With two exceptions all averages for a single profile stayed below 7 {mu}g/m{sup 3}. Larger individual excursions were observed. In some cases, in particular in regions of steep aerosol gradients at layer boundaries, most probably the lidar values cause the deviation, while in other cases the ECC-sonde is suspected to yield erroneous results. For the measured standard deviation those retrieved from DIAL measurements are generally larger than measured by the ECC-sondes, especially in regions of inhomogeneous aerosol distribution. For the measurements reported here, this is attributed to residual errors in the aerosol correction of the DIAL measurements. The general agreement found in this intercomparison is regarded as excellent, DIAL is proven to be a very valuable tool for detailed studies of the ozone distribution in the lower troposphere. (orig.)

  4. Results of the Argentinian intercomparison on internal dosimetry – 2014. Interpretation of monitoring data for effective dose assessment due to internal exposure

    International Nuclear Information System (INIS)

    Rojo, A.M.; Puerta, N.; Gossio, S.; Gómez Parada, I.

    2015-01-01

    Internal dosimetry intercomparisons are essential for the verification of the models applied and the results consistency. To that aim, in 2014 the National Intercomparison Exercise was organized and coordinated by the Internal Dosimetry Laboratory of the Nuclear Regulatory Authority (ARN) of Argentina. Four simulated cases covering intakes of “1”3”1I, “1”3”7Cs and tritium were proposed. The exercise counted with the participation of four internal dosimetry services from the nuclear power plants (NA-SA CNA and NA-SA CNE) and the CNEA Atomic Centres: Bariloche (CAB) and Ezeiza (CAE). This report shows a complete analysis of the participant’s results in this exercise. (authors) [es

  5. Report on the intercomparison run IAEA-384. Radionuclides in Fangataufa lagoon sediment

    International Nuclear Information System (INIS)

    Povinec, P.P.; Pham, M.K.

    2000-01-01

    The accurate and precise determinations of radionuclide concentrations in marine samples are important aspects of marine radioactivity assessments and the use of radionuclides in studies of oceanographic processes. To address the problem of data quality, and to assist Member States in verifying the performance of their laboratories, the IAEA Marine Environment Laboratory (MEL) in Monaco has conducted intercomparison exercises on radionuclides in marine samples for many years as part of its contribution to the IAEA's programme of Analytical Quality Control Services (AQCS). For this intercomparison exercise, in 1996 IAEA-MEL collected sediment in Fangataufa lagoon, French Polynesia. The sample aliquots were distributed during 1997-1998 for intercomparison of anthropogenic and natural radionuclides. 110 laboratories worldwide agreed to participate. Of these, only 94 sent results which could be used in the evaluation of this intercomparison exercise. This report describes the results obtained from 94 laboratories on anthropogenic and natural radionuclide determinations in Fangataufa lagoon sediment

  6. Report on the intercomparison run IAEA-384. Radionuclides in Fangataufa lagoon sediment

    Energy Technology Data Exchange (ETDEWEB)

    Povinec, P P; Pham, M K

    2000-07-01

    The accurate and precise determinations of radionuclide concentrations in marine samples are important aspects of marine radioactivity assessments and the use of radionuclides in studies of oceanographic processes. To address the problem of data quality, and to assist Member States in verifying the performance of their laboratories, the IAEA Marine Environment Laboratory (MEL) in Monaco has conducted intercomparison exercises on radionuclides in marine samples for many years as part of its contribution to the IAEA's programme of Analytical Quality Control Services (AQCS). For this intercomparison exercise, in 1996 IAEA-MEL collected sediment in Fangataufa lagoon, French Polynesia. The sample aliquots were distributed during 1997-1998 for intercomparison of anthropogenic and natural radionuclides. 110 laboratories worldwide agreed to participate. Of these, only 94 sent results which could be used in the evaluation of this intercomparison exercise. This report describes the results obtained from 94 laboratories on anthropogenic and natural radionuclide determinations in Fangataufa lagoon sediment.

  7. IAEA intercomparisons in the frame of the occupational radiation protection programme

    International Nuclear Information System (INIS)

    Mrabit, K.; Cruz Suarez, R.

    2005-01-01

    The IAEA safety activities to support the assessment of occupational exposure through a comprehensive set of safety guides, safety reports and other related documents will soon be completed. Several intercomparison exercises were organized by the IAEA on the determination of radionuclides in human urine samples, whole body counting and external dosimetry. These previous intercomparison exercises revealed significant differences in the approaches, methods and assumptions, and consequently in the results. This underlined the importance of this kind of intercomparison programme as a key element of the international harmonization of quantities and units. The purpose of this paper is to present the current and future IAEA activities in support of assessment of occupational exposure by organizing intercomparison runs

  8. HPLC/DAD Intercomparison on Phytoplankton Pigments (HIP-1, HIP-2, HIP-3 and HIP-4)

    OpenAIRE

    CANUTI Elisabetta; RAS Josephine; GRUNG Merete; ROTTGERS Rudiger; COSTA GOELA Priscilla; ARTUSO Florinda; CATALDI Dario

    2016-01-01

    From 2009 to 2015, in the context of the MERIS (Medium Resolution Imaging Spectrometer) validation activities, the JRC Marine Optical Laboratory organised four HPLC Intercomparison exercises for Phytoplankton Pigment measurements (HIP-1, HIP-2, HIP-3 and HIP-4), involving seven European accredited and reference laboratories. The objectives of these intercomparison exercises were: creating a reference community at European level for phytoplankton pigment analysis capable of supporting satel...

  9. Intercomparison run for uranium and tritium determination in urine samples, organised by Nuclear Regulatory Authority, Argentina

    CERN Document Server

    Serdeiro, N H; Equillor, H E

    2003-01-01

    The Nuclear Regulatory Authority (ARN), Argentina, has carried out an intercomparison run for tritium and uranium determination in urine, in November 2002. The aim of this exercise was to assess the performance of the laboratories that usually inform these radionuclides and to provide technical support in order to have an appropriate occupational monitoring in vitro. In the present work, the results of the intercomparison and the assessment of each laboratory are published.

  10. Intercomparison run for uranium and tritium determination in urine samples, organised by Nuclear Regulatory Authority, Argentina

    International Nuclear Information System (INIS)

    Serdeiro, Nelida H.; Equillor, Hugo E.; Bonino, Nestor O.

    2003-01-01

    The Nuclear Regulatory Authority (ARN), Argentina, has carried out an intercomparison run for tritium and uranium determination in urine, in November 2002. The aim of this exercise was to assess the performance of the laboratories that usually inform these radionuclides and to provide technical support in order to have an appropriate occupational monitoring in vitro. In the present work, the results of the intercomparison and the assessment of each laboratory are published. (author)

  11. Evaluation of Brazilian intercomparison program data from 1991 to 1995 of radionuclide assays in environmental samples

    International Nuclear Information System (INIS)

    Vianna, Maria Elizabeth Couto M.; Tauhata, Luiz; Oliveira, Antonio Eduardo de; Oliveira, Josue Peter de; Clain, Almir Faria; Ferreira, Ana Cristina M.

    1998-01-01

    Historical radioanalytical data from the Institute of Radiation Protection and Dosimetry (IRD) national intercomparison program from 1991 to 1995 were analyzed to evaluate the performance of sixteen Brazilian laboratories in radionuclide analyses in environmental samples. Data are comprised of measurements of radionuclides in 435 spiked environmental samples distributed in fifteen