WorldWideScience

Sample records for climate numerical analyses

  1. Numeric tools for tachogram analyse

    Directory of Open Access Journals (Sweden)

    Artur RYGUŁA

    2007-01-01

    Full Text Available Paper describes numeric application supporting driving analysis process on attitude of tachogram data. Actual accessible units recording road and speed in function of the time were used. Also potential optimisation areas of driving were shown. Additionally in the paper are presented road safety level in Poland in the context of dangerous driver’s behaviour.

  2. Numeric tools for tachogram analyse

    OpenAIRE

    Artur RYGUŁA; Andrzej MITAS

    2007-01-01

    Paper describes numeric application supporting driving analysis process on attitude of tachogram data. Actual accessible units recording road and speed in function of the time were used. Also potential optimisation areas of driving were shown. Additionally in the paper are presented road safety level in Poland in the context of dangerous driver’s behaviour.

  3. Impact of wind-driven rain on historic brick wall buildings in a moderately cold and humid climate: Numerical analyses of mould growth risk, indoor climate and energy consumption

    DEFF Research Database (Denmark)

    Masaru, Abuku; Janssen, Hans; Roels, Staf

    2009-01-01

    This paper gives an onset to whole building hygrothermal modelling in which the interaction between interior and exterior climates via building enclosures is simulated under a moderately cold and humid climate. The focus is particularly on the impact of wind-driven rain (WDR) oil the hygrothermal...... response, mould growth at interior wall surfaces, indoor climate and energy consumption. First the WDR load oil the facades of a 4 m x 4 m x 10 m tower is determined. Then the hygrothermal behaviour of the brick walls is analysed oil a horizontal slice through the tower. The simulations demonstrate...... that WDR loads can have a significant impact on mould growth especially at the edges of the walls. Finally, for the case analysed, the WDR load Causes a significant increase of indoor relative humidity and energy consumption for heating. (C) 2008 Elsevier B.V. All rights reserved....

  4. Constructing a framework for risk analyses of climate change effects on the water budget of differently sloped vineyards with a numeric simulation using the Monte Carlo method coupled to a water balance model.

    Science.gov (United States)

    Hofmann, Marco; Lux, Robert; Schultz, Hans R

    2014-01-01

    Grapes for wine production are a highly climate sensitive crop and vineyard water budget is a decisive factor in quality formation. In order to conduct risk assessments for climate change effects in viticulture models are needed which can be applied to complete growing regions. We first modified an existing simplified geometric vineyard model of radiation interception and resulting water use to incorporate numerical Monte Carlo simulations and the physical aspects of radiation interactions between canopy and vineyard slope and azimuth. We then used four regional climate models to assess for possible effects on the water budget of selected vineyard sites up 2100. The model was developed to describe the partitioning of short-wave radiation between grapevine canopy and soil surface, respectively, green cover, necessary to calculate vineyard evapotranspiration. Soil water storage was allocated to two sub reservoirs. The model was adopted for steep slope vineyards based on coordinate transformation and validated against measurements of grapevine sap flow and soil water content determined down to 1.6 m depth at three different sites over 2 years. The results showed good agreement of modeled and observed soil water dynamics of vineyards with large variations in site specific soil water holding capacity (SWC) and viticultural management. Simulated sap flow was in overall good agreement with measured sap flow but site-specific responses of sap flow to potential evapotranspiration were observed. The analyses of climate change impacts on vineyard water budget demonstrated the importance of site-specific assessment due to natural variations in SWC. The improved model was capable of describing seasonal and site-specific dynamics in soil water content and could be used in an amended version to estimate changes in the water budget of entire grape growing areas due to evolving climatic changes. PMID:25540646

  5. Constructing a framework for risk analyses of climate change effects on the water budget of differently sloped vineyards with a numeric simulation using the Monte Carlo method coupled to a water balance model

    Directory of Open Access Journals (Sweden)

    Marco eHofmann

    2014-12-01

    Full Text Available Grapes for wine production are a highly climate sensitive crop and vineyard water budget is a decisive factor in quality formation. In order to conduct risk assessments for climate change effects in viticulture models are needed which can be applied to complete growing regions. We first modified an existing simplified geometric vineyard model of radiation interception and resulting water use to incorporate numerical Monte Carlo simulations and the physical aspects of radiation interactions between canopy and vineyard slope and azimuth. We then used four regional climate models to assess for possible effects on the water budget of selected vineyard sites up 2100. The model was developed to describe the partitioning of short-wave radiation between grapevine canopy and soil surface, respectively green cover, necessary to calculate vineyard evapotranspiration. Soil water storage was allocated to two sub reservoirs. The model was adopted for steep slope vineyards based on coordinate transformation and validated against measurements of grapevine sap flow and soil water content determined down to 1.6 m depth at three different sites over two years. The results showed good agreement of modelled and observed soil water dynamics of vineyards with large variations in site specific soil water holding capacity and viticultural management. Simulated sap flow was in overall good agreement with measured sap flow but site-specific responses of sap flow to potential evapotranspiration were observed. The analyses of climate change impacts on vineyard water budget demonstrated the importance of site-specific assessment due to natural variations in soil water holding capacity. The improved model was capable of describing seasonal and site-specific dynamics in soil water content and could be used in an amended version to estimate changes in the water budget of entire grape growing areas due to evolving climatic changes.

  6. Constructing a framework for risk analyses of climate change effects on the water budget of differently sloped vineyards with a numeric simulation using the Monte Carlo method coupled to a water balance model.

    Science.gov (United States)

    Hofmann, Marco; Lux, Robert; Schultz, Hans R

    2014-01-01

    Grapes for wine production are a highly climate sensitive crop and vineyard water budget is a decisive factor in quality formation. In order to conduct risk assessments for climate change effects in viticulture models are needed which can be applied to complete growing regions. We first modified an existing simplified geometric vineyard model of radiation interception and resulting water use to incorporate numerical Monte Carlo simulations and the physical aspects of radiation interactions between canopy and vineyard slope and azimuth. We then used four regional climate models to assess for possible effects on the water budget of selected vineyard sites up 2100. The model was developed to describe the partitioning of short-wave radiation between grapevine canopy and soil surface, respectively, green cover, necessary to calculate vineyard evapotranspiration. Soil water storage was allocated to two sub reservoirs. The model was adopted for steep slope vineyards based on coordinate transformation and validated against measurements of grapevine sap flow and soil water content determined down to 1.6 m depth at three different sites over 2 years. The results showed good agreement of modeled and observed soil water dynamics of vineyards with large variations in site specific soil water holding capacity (SWC) and viticultural management. Simulated sap flow was in overall good agreement with measured sap flow but site-specific responses of sap flow to potential evapotranspiration were observed. The analyses of climate change impacts on vineyard water budget demonstrated the importance of site-specific assessment due to natural variations in SWC. The improved model was capable of describing seasonal and site-specific dynamics in soil water content and could be used in an amended version to estimate changes in the water budget of entire grape growing areas due to evolving climatic changes.

  7. A Climate System Model, Numerical Simulation and Climate Predictability

    Institute of Scientific and Technical Information of China (English)

    ZENG Qingcun; WANG Huijun; LIN Zhaohui; ZHOU Guangqing; YU Yongqiang

    2007-01-01

    @@ The implementation of the project has lasted for more than 20 years. As a result, the following key innovative achievements have been obtained, ranging from the basic theory of climate dynamics, numerical model development and its related computational theory to the dynamical climate prediction using the climate system models:

  8. Climate system model, numerical simulation and climate predictability

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Thanks to its work of past more than 20 years,a research team led by Prof.ZENG Qingcun and Prof.WANG Huijun from the CAS Institute of Atmospheric Physics (IAP) has scored innovative achievements in their studies of basic theory of climate dynamics,numerical model development,its related computational theory,and the dynamical climate prediction using the climate system models.Their work received a second prize of the National Award for Natural Sciences in 2005.

  9. Numerical Analyses of Plate Loading Test

    Directory of Open Access Journals (Sweden)

    Ionuţ-Ovidiu Toma

    2009-01-01

    Full Text Available A numerical simulation of plate loading test, in order to underlines the size effect on settlements and derived values of geotechnical parameters, is shown. The study is based on the comparison between the results obtained by Finite Element Method (FEM using the Mohr-Coulomb soil model and by some observations from literature. The obtained numerical results revealed that the subgrade reaction coefficient is strictly dependent on parameters like size of the loaded area and loading magnitude, and thus completely general and generic, and not a fundamental material property of soil that can somehow be determined rationally, as often one claims to be.

  10. Use of EBSD Data in Numerical Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Becker, R; Wiland, H

    2000-01-14

    Experimentation, theory and modeling have all played vital roles in defining what is known about microstructural evolution and the effects of microstructure on material properties. Recently, technology has become an enabling factor, allowing significant advances to be made on several fronts. Experimental evidence of crystallographic slip and the basic theory of crystal plasticity were established in the early 20th Century, and the theory and models evolved incrementally over the next 60 years. (Asaro provides a comprehensive review of the mechanisms and basic plasticity models.) During this time modeling was primarily concerned with the average response of polycrystalline aggregates. While some detailed finite element modeling (FEM) with crystal plasticity constitutive relations was done in the early 1980s, such simulations over taxed the capabilities of the available computer hardware. Advances in computer capability led to a flurry of activity in finite element modeling in the next 10 years, increasing understanding of microstructure evolution and pushing the limits of theories and material characterization. Automated Electron Back Scatter Diffraction (EBSD) has produced a similar revolution in material characterization. The data collected is extensive and many questions about the evolution of microstructure and its role in determining mechanic properties can now be addressed. It is also now possible to obtain sufficient information about lattice orientations on a fine enough scale to allow detailed quantitative comparisons of experiments and newly emerging large scale numerical simulations. The insight gained from the coupling of EBSD and FEM studies will provide impetus for further development of microstructure models and theories of microstructure evolution. Early studies connecting EBSD data to finite element models used manual measurements to define initial orientations for the simulation. In one study, manual measurements of the deformed structure were also

  11. Advancement and prospect of short-term numerical climate prediction

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The defects of present methods of short-term numerical climate prediction are discussed in this paper, and four challenging problems are put forward. Considering our under developed computer conditions, we should innovate in the approcuch of numerical climate prediction on the basis of our own achievements and experiences in the field of short-term numerical climate prediction. It is possibly an effective way to settle the present defects of short-term numerical climate prediction.``

  12. Dynamic behaviour of a rolling tyre: Experimental and numerical analyses

    Science.gov (United States)

    Gonzalez Diaz, Cristobal; Kindt, Peter; Middelberg, Jason; Vercammen, Stijn; Thiry, Christophe; Close, Roland; Leyssens, Jan

    2016-03-01

    Based on the results of experimental and numerical analyses, the effect of rotation on the tyre dynamic behaviour is investigated. Better understanding of these effects will further improve the ability to control and optimize the noise and vibrations that result from the interaction between the road surface and the rolling tyre. Therefore, more understanding in the complex tyre dynamic properties will contribute to develop tyre design strategies to lower the tyre/road noise while less affecting other tyre performances. The presented work is performed in the framework of the European industry-academia project TIRE-DYN, with partners Goodyear, Katholieke Universiteit Leuven and LMS International. The effect of rotation on the tyre dynamic behaviour is quantified for different operating conditions of the tyre, such as load, air pressure and rotation speed. By means of experimental and numerical analyses, the effects of rotation on the tyre dynamic behaviour are studied.

  13. Analysing climate impact on energy demand using the MOLAND model

    OpenAIRE

    Liu, Xiaochen; Twumasi, Bright Osei

    2008-01-01

    The importance and contribution of climate to energy demand are discussed. A linear regression model is developed to analyse future energy demand corresponding to climate change. The methodology for spatial analysis and integration to MOLAND are also provided in order to investigate possible consequences of different urban development paths on energy consumption patterns.

  14. NUMERICAL ANALYSES OF THE UNDERGROUND EXPLOITATION OF DIMENSION STONE

    Directory of Open Access Journals (Sweden)

    Biljana Kovačević-Zelić

    1996-12-01

    Full Text Available Underground exploitation of dimension stone is spreading lately for three main reasons; economy, organisation and environment. Moreover, underground openings can be used for many purposes. Underground exploitation is different from surface quarrying only in the first stage, the removal of top slice, descending slices are worked as in conventional quarries. In underground stone quarries, stability problems require adequate studies in order to avoid expensive artificial support measures, The article presents numerical analyses of an underground stone quarry made using of the finite difference code FLAC (the paper is published in Croatian.

  15. Mathematical and Numerical Analyses of Peridynamics for Multiscale Materials Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Du, Qiang [Pennsylvania State Univ., State College, PA (United States)

    2014-11-12

    The rational design of materials, the development of accurate and efficient material simulation algorithms, and the determination of the response of materials to environments and loads occurring in practice all require an understanding of mechanics at disparate spatial and temporal scales. The project addresses mathematical and numerical analyses for material problems for which relevant scales range from those usually treated by molecular dynamics all the way up to those most often treated by classical elasticity. The prevalent approach towards developing a multiscale material model couples two or more well known models, e.g., molecular dynamics and classical elasticity, each of which is useful at a different scale, creating a multiscale multi-model. However, the challenges behind such a coupling are formidable and largely arise because the atomistic and continuum models employ nonlocal and local models of force, respectively. The project focuses on a multiscale analysis of the peridynamics materials model. Peridynamics can be used as a transition between molecular dynamics and classical elasticity so that the difficulties encountered when directly coupling those two models are mitigated. In addition, in some situations, peridynamics can be used all by itself as a material model that accurately and efficiently captures the behavior of materials over a wide range of spatial and temporal scales. Peridynamics is well suited to these purposes because it employs a nonlocal model of force, analogous to that of molecular dynamics; furthermore, at sufficiently large length scales and assuming smooth deformation, peridynamics can be approximated by classical elasticity. The project will extend the emerging mathematical and numerical analysis of peridynamics. One goal is to develop a peridynamics-enabled multiscale multi-model that potentially provides a new and more extensive mathematical basis for coupling classical elasticity and molecular dynamics, thus enabling next

  16. NASA Earth Exchange (NEX) Supporting Analyses for National Climate Assessments

    Science.gov (United States)

    Nemani, R. R.; Thrasher, B. L.; Wang, W.; Lee, T. J.; Melton, F. S.; Dungan, J. L.; Michaelis, A.

    2015-12-01

    The NASA Earth Exchange (NEX) is a collaborative computing platform that has been developed with the objective of bringing scientists together with the software tools, massive global datasets, and supercomputing resources necessary to accelerate research in Earth systems science and global change. NEX supports several research projects that are closely related with the National Climate Assessment including the generation of high-resolution climate projections, identification of trends and extremes in climate variables and the evaluation of their impacts on regional carbon/water cycles and biodiversity, the development of land-use management and adaptation strategies for climate-change scenarios, and even the exploration of climate mitigation through geo-engineering. Scientists also use the large collection of satellite data on NEX to conduct research on quantifying spatial and temporal changes in land surface processes in response to climate and land-cover-land-use changes. Researchers, leveraging NEX's massive compute/storage resources, have used statistical techniques to downscale the coarse-resolution CMIP5 projections to fulfill the demands of the community for a wide range of climate change impact analyses. The DCP-30 (Downscaled Climate Projections at 30 arcsecond) for the conterminous US at monthly, ~1km resolution and the GDDP (Global Daily Downscaled Projections) for the entire world at daily, 25km resolution are now widely used in climate research and applications, as well as for communicating climate change. In order to serve a broader community, the NEX team in collaboration with Amazon, Inc, created the OpenNEX platform. OpenNEX provides ready access to NEX data holdings, including the NEX-DCP30 and GDDP datasets along with a number of pertinent analysis tools and workflows on the AWS infrastructure in the form of publicly available, self contained, fully functional Amazon Machine Images (AMI's) for anyone interested in global climate change.

  17. Improving Climate Communication through Comprehensive Linguistic Analyses Using Computational Tools

    Science.gov (United States)

    Gann, T. M.; Matlock, T.

    2014-12-01

    An important lesson on climate communication research is that there is no single way to reach out and inform the public. Different groups conceptualize climate issues in different ways and different groups have different values and assumptions. This variability makes it extremely difficult to effectively and objectively communicate climate information. One of the main challenges is the following: How do we acquire a better understanding of how values and assumptions vary across groups, including political groups? A necessary starting point is to pay close attention to the linguistic content of messages used across current popular media sources. Careful analyses of that information—including how it is realized in language for conservative and progressive media—may ultimately help climate scientists, government agency officials, journalists and others develop more effective messages. Past research has looked at partisan media coverage of climate change, but little attention has been given to the fine-grained linguistic content of such media. And when researchers have done detailed linguistic analyses, they have relied primarily on hand-coding, an approach that is costly, labor intensive, and time-consuming. Our project, building on recent work on partisan news media (Gann & Matlock, 2014; under review) uses high dimensional semantic analyses and other methods of automated classification techniques from the field of natural language processing to quantify how climate issues are characterized in media sources that differ according to political orientation. In addition to discussing varied linguistic patterns, we share new methods for improving climate communication for varied stakeholders, and for developing better assessments of their effectiveness.

  18. Using Weather Data and Climate Model Output in Economic Analyses of Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Auffhammer, Maximilian [University of California at Berkeley; Hsiang, Solomon M. [Princeton University; Schlenker, Wolfram [Columbia University; Sobel, Adam H. [Columbia University

    2013-06-28

    Economists are increasingly using weather data and climate model output in analyses of the economic impacts of climate change. This article introduces a set of weather data sets and climate models that are frequently used, discusses the most common mistakes economists make in using these products, and identifies ways to avoid these pitfalls. We first provide an introduction to weather data, including a summary of the types of datasets available, and then discuss five common pitfalls that empirical researchers should be aware of when using historical weather data as explanatory variables in econometric applications. We then provide a brief overview of climate models and discuss two common and significant errors often made by economists when climate model output is used to simulate the future impacts of climate change on an economic outcome of interest.

  19. Seasonal cycle of Martian climate : Experimental data and numerical simulation

    NARCIS (Netherlands)

    Rodin, A. V.; Willson, R. J.

    2006-01-01

    The most adequate theoretical method of investigating the present-day Martian climate is numerical simulation based on a model of general circulation of the atmosphere. First and foremost, such models encounter the greatest difficulties in description of aerosols and clouds, which in turn essentiall

  20. Numerical tables on physical and chemical analyses of Rhine water

    International Nuclear Information System (INIS)

    Tables on the places of measurement, the sampling methods and the methods of analysis used. The numerical tables of the measurement results are broken down in general parameters, organic, entrophicating and anorganic substances, orgnic micro-pollutants and radioactivity. (GG)

  1. Numerical analyses in the design of umbrella arch systems

    Institute of Scientific and Technical Information of China (English)

    J. Oke; N. Vlachopoulos; M.S. Diederichs

    2014-01-01

    Due to advances in numerical modelling, it is possible to capture complex support-ground interaction in two dimensions and three dimensions for mechanical analysis of complex tunnel support systems, although such analysis may still be too complex for routine design calculations. One such system is the forepole element, installed within the umbrella arch temporary support system for tunnels, which warrants such support measures. A review of engineering literature illustrates that a lack of design standards exists regarding the use of forepole elements. Therefore, when designing such support, de-signers must employ complex numerical models combined with engineering judgement. With reference to past developments by others and new investigations conducted by the authors on the Driskos tunnel in Greece and the Istanbul metro, this paper illustrates how advanced numerical modelling tools can facilitate understanding of the influences of design parameters associated with the use of forepole ele-ments. In addition, this paper highlights the complexity of the ground-support interaction when simulated with two-dimensional (2D) finite element software using a homogenous reinforced region, and three-dimensional (3D) finite difference software using structural elements. This paper further il-lustrates sequential optimisation of two design parameters (spacing and overlap) using numerical modelling. With regard to capturing system behaviour in the region between forepoles for the purpose of dimensioning spacing, this paper employs three distinctive advanced numerical models:particle codes, continuous finite element models with joint set and Voronoi blocks. Finally, to capture the behaviour/failure ahead of the tunnel face (overlap parameter), 2D axisymmetric models are employed. Finally, conclusions of 2D and 3D numerical assessment on the Driskos tunnel are drawn. The data enriched case study is examined to determine an optimum design, based on the proposed optimisation of

  2. Numerical and Experimental Analyses of Residual Stresses in

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Hattel, Jesper; Lorentzen, Torben

    1999-01-01

    Butt-welding in one pass with SMAW of two 10mm mild steel plates is investigated. In order to predict the residual stress fields associated with the welding procedure, a finite element model in 3D has been developed in ABAQUS. This model applies a sequential thermal and mechanical numerical...

  3. Mathematical and Numerical Analyses of Peridynamics for Multiscale Materials Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Gunzburger, Max [Florida State Univ., Tallahassee, FL (United States)

    2015-02-17

    We have treated the modeling, analysis, numerical analysis, and algorithmic development for nonlocal models of diffusion and mechanics. Variational formulations were developed and finite element methods were developed based on those formulations for both steady state and time dependent problems. Obstacle problems and optimization problems for the nonlocal models were also treated and connections made with fractional derivative models.

  4. Analytical and numerical analyses of hydrologic well-bore experiments

    International Nuclear Information System (INIS)

    An analytical approximate method and a finite-difference numerical model (based on the rate at which a borehole fills with water) were developed to estimate permeability of the Magenta Formation in southeastern New Mexico near the proposed Waste Isolation Pilot Project (WIPP) site. The analytical treatment applies to certain simple geometries with idealized boundary conditions (constant properties, ground water compressibility negligible). Permissible geometries include water-collecting cylinders with large needle-like aspect ratios located beneath the water table. The analytical treatment clearly shows the sensitivity of inferences and conclusions to material properties and geometries. Much of the existing well-bore fill-rate data fall within the range of validity of this simplified analysis. Admission of compressibility effects into the generalized Darcy law, and a nondimensionalization of the equations identify the range of experimental conditions and material properties for which the approximations are invalid. In the numerical capability to complement this analytical treatment, numerous restrictions have been removed so that the code can treat complex geometries for a variety of boundary conditions and variable properties. The compressibility term that is excluded in the analytical treatment is maintained in these numerical solutions. The resulting equations are formally parabolicand can be solved by an implicit integrator with guaranteed stability. The two methods, applied to several different experimental situations, agree with each other. 9 figures, 3 tables

  5. Numerical and theoretical analyses of underground explosion cavity decoupling

    Science.gov (United States)

    Jensen, R.; Aldridge, D. F.; Chael, E. P.

    2013-12-01

    It has long been established that the amplitudes of seismic waves radiated from an underground explosion can be reduced by detonating the explosive within a fluid-filled cavity of adequate size. Significant amplitude reduction occurs because the reflection coefficient at the fluid/rock interface (i.e., the cavity wall) is large. In fact, the DC frequency limit of the reflection coefficient for a spherically-diverging seismic wave incident upon a concentric spherical interface is -1.0, independent of radius of curvature and all material properties. In order to quantify to the degree of amplitude reduction expected in various realistic scenarios, we are conducting mathematical and numerical investigations into the so-called 'cavity decoupling problem' for a buried explosion. Our working tool is a numerical algorithm for simulating fully-coupled seismic and acoustic wave propagation in mixed solid/fluid media. Solution methodology involves explicit, time-domain, finite differencing of the elastodynamic velocity-stress partial differential system on a three-dimensional staggered spatial grid. Conditional logic is used to avoid shear stress updating within fluid zones; this approach leads to computational efficiency gains for models containing a significant proportion of ideal fluid. Numerical stability and accuracy are maintained at air/rock interfaces (where the contrast in mass density is on the order of 1 to 2000) via an FD operator 'order switching' formalism. The fourth-order spatial FD operator used throughout the bulk of the earth model is reduced to second-order in the immediate vicinity of a high-contrast interface. Point explosions detonated at the center of an air-filled or water-filled spherical cavity lead to strong resonant oscillations in radiated seismic energy, with period controlled by cavity radius and sound speed of the fill fluid. If the explosion is off-center, or the cavity is non-spherical, shear waves are generated in the surrounding elastic

  6. Application of climatic indices to analyse viticultural suitability in Extremadura, south-western Spain

    Science.gov (United States)

    Moral, Francisco J.; Rebollo, Francisco J.; Paniagua, Luis L.; García, Abelardo; de Salazar, Enrique Martínez

    2016-01-01

    Although climate is recognised as one of the main drivers of viticulture success, its main features have not been sufficiently described in many viticultural regions, including Extremadura, which contains one of the largest grapevine-growing areas in Europe. Using climatic data from 80 weather stations located throughout Extremadura, seven bioclimatic indices were calculated to estimate heat accumulation and potential water balance during the growing season and the thermal regime during the ripening of grapes. Differences in some climatic indices were found, and after a multivariate geographic analysis, four groups were delimited containing weather stations with similar climatic features, with variability between groups explained by heat accumulation and tempearture and thermal amplitude during the ripening season. Suitability for cultivation of grapevines without thermal restriction and temperate nights during the ripening period are the main characteristics of the weather stations studied, but spatial variability found in climatic potential denotes the importance of differentiating locations to properly relate the viticultural climate to grape quality factors and the style of wines produced. The climatic features of the four groups are very similar to those described in other viticultural regions, including those in close proximity to Extremadura and others worldwide, but few studies have used broad and updated temporal climate data for computing bioclimatic indices as in this case study. Finally, trends in climate indices were analysed. Results revealed that all groups have experienced warmer growing seasons, driven mainly by changes in minimum temperatures. This fact has numerous potential impacts, including changes in grapevine phenological timing, disruption of balanced composition in grapes (ultimately affecting wine characteristics), alterations in varieties grown and spatial changes in viable winegrape-growing zones.

  7. Experimental and numerical analyses of micro rotary shaft pumps

    International Nuclear Information System (INIS)

    This paper presents experimental and numerical results obtained with micro rotary shaft pumps (RSP). Impellers with a diameter of 2.5 mm, different outlet widths and blade number were coupled with semicircular volutes with different eccentricities. Experimental data for every impeller–volute couple were reported and include the flow rate, head and overall efficiency. Different rotational speeds were tested up to 24 000 rpm, obtaining pressure increases up to 5.7 kPa and flow rates up to 80 ml min−1. The non-dimensional performance was also computed obtaining the maximum head coefficient of 0.49 and the maximum flow coefficient of 0.138. Furthermore, experimental data were compared with 3D time-dependent CFD simulations. The focus of the simulation was to study the flow field structure inside the impeller and in the volute. Moreover, CFD data allowed for the calculation of the hydraulic efficiency of the pump and for the impeller to highlight the stator rotor interference influence on the pump characteristics, as well as to show the distribution of losses inside the volute

  8. Numerical simulations of hydraulic redistribution across climates: The role of the root hydraulic conductivities

    Science.gov (United States)

    Quijano, Juan C.; Kumar, Praveen

    2015-10-01

    Hydraulic redistribution, a process by which vegetation roots redistribute soil moisture, has been recognized as an important mechanism impacting several processes that regulate plant water uptake, energy and water partitioning, and biogeochemical cycling. We analyze how the magnitude of hydraulic redistribution varies across ecosystems that are exposed to different climates and seasonal patterns of incoming shortwave radiation and precipitation. Numerical simulation studies are performed over 10 Ameriflux sites, which show that hydraulic redistribution predictions are significantly influenced by the specified root hydraulic conductivities. We performed sensitivity analyses by considering expected ranges of root conductivities based on previous experimental studies, and found contrasting patterns in energy-limited and water-limited ecosystems. In energy-limited ecosystems, there is a threshold above which high root conductivities enhance hydraulic redistribution with no increase in transpiration, while in water-limited ecosystems increase in root conductivities was always associated with enhancements in both transpiration and hydraulic redistribution. Further we found differences in the magnitude and seasonality of hydraulic redistribution and transpiration across different climates, regulated by interplay between precipitation and transpiration. The annual hydraulic redistribution to transpiration flux ratio (HR/Tr) was significant in Mediterranean climates (HR/Tr ≈ 30%), and in the tropical humid climates (HR/Tr ≈ 15%). However, in the continental climates hydraulic redistribution occurs only during sporadic precipitation events throughout the summer resulting in lower annual magnitudes (HR/Tr hydrology, and enhance our understanding about the variability of hydraulic redistribution across different climates.

  9. Analyses on Climate Characteristics in Xingtai City during 1954 - 2010

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective]The research aimed to analyze climate characteristics in Xingtai City during 1954-2010.[Method] Based on climate data in Xingtai City during 1954-2010,by using line chart,trend chart,climatic variability and statistical diagram,the climate characteristics in Xingtai City in 57 years were analyzed.[Result] The annual average temperature,annual average maximum and minimum temperatures in Xingtai City during 1954-2010 all presented gradual rise trend.The rise velocity of annual average maximum tempe...

  10. Comparison of Numerical Analyses with a Static Load Test of a Continuous Flight Auger Pile

    Directory of Open Access Journals (Sweden)

    Hoľko Michal

    2014-12-01

    Full Text Available The article deals with numerical analyses of a Continuous Flight Auger (CFA pile. The analyses include a comparison of calculated and measured load-settlement curves as well as a comparison of the load distribution over a pile's length. The numerical analyses were executed using two types of software, i.e., Ansys and Plaxis, which are based on FEM calculations. Both types of software are different from each other in the way they create numerical models, model the interface between the pile and soil, and use constitutive material models. The analyses have been prepared in the form of a parametric study, where the method of modelling the interface and the material models of the soil are compared and analysed.

  11. An abrupt stochastic damage function to analyse climate policy benefits

    OpenAIRE

    Ha-Duong, Minh; Dumas, Patrice

    2004-01-01

    Chapter in Alain Haurie and Laurent Viguier (eds.) 2005, The coupling of climate and economic dynamics, Essays on Integrated Assessment. Series: Advances in Global Change Research, Vol. 22 , Kluwerhttp://www.centre-cired.fr/perso/haduong/files/Dumas.ea-2004-AbruptStochasticDamage.pdf This paper studies uncertainty about the non-linearity of climate change impact. The DIAM 2.3 model is used to compute the sensitivity of optimal CO2 emissions paths with respect to damage function parameters....

  12. How scaling fluctuation analyses can transform our view of the climate

    Science.gov (United States)

    Lovejoy, Shaun; Schertzer, Daniel

    2013-04-01

    There exist a bewildering diversity of proxy climate data including tree rings, ice cores, lake varves, boreholes, ice cores, pollen, foraminifera, corals and speleothems. Their quantitative use raises numerous questions of interpretation and calibration. Even in classical cases - such as the isotope signal in ice cores - the usual assumption of linear dependence on ambient temperature is only a first approximation. In other cases - such as speleothems - the isotope signals arise from multiple causes (which are not always understood) and this hinders their widespread use. We argue that traditional interpretations and calibrations - based on essentially deterministic comparisons between instrumental data, model outputs and proxies (albeit with the help of uncertainty analyses) - have been both overly ambitious while simultaneously underexploiting the data. The former since comparisons typically involve series at different temporal resolutions and from different geographical locations - one does not expect agreement in a deterministic sense, while with respect to climate models, one only expects statistical correspondences. The proxies are underexploited since comparisons are done at unique temporal and / or spatial resolutions whereas the fluctuations they describe provide information over wide ranges of scale. A convenient method of overcoming these difficulties is the use of fluctuation analysis systematically applied over the full range of available scales to determine the scaling proeprties. The new transformative element presented here, is to define fluctuations ΔT in a series T(t) at scale Δt not by differences (ΔT(Δt) = T(t+Δt) - T(t)) but rather by the difference in the means over the first and second halves of the lag Δt . This seemingly minor change - technically from "poor man's" to "Haar" wavelets - turns out to make a huge difference since for example, it is adequate for analysing temperatures from seconds to hundreds of millions of years yet

  13. Numerical techniques in linear duct acoustics. [finite difference and finite element analyses

    Science.gov (United States)

    Baumeister, K. J.

    1980-01-01

    Both finite difference and finite element analyses of small amplitude (linear) sound propagation in straight and variable area ducts with flow, as might be found in a typical turboject engine duct, muffler, or industrial ventilation system, are reviewed. Both steady state and transient theories are discussed. Emphasis is placed on the advantages and limitations associated with the various numerical techniques. Examples of practical problems are given for which the numerical techniques have been applied.

  14. Climate Prediction Center (CPC) US daily temperature analyses

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The U.S. daily temperature analyses are maps depicting various temperature quantities utilizing daily maximum and minimum temperature data across the US. Maps are...

  15. X-ray CT analyses, models and numerical simulations: a comparison with petrophysical analyses in an experimental CO2 study

    Science.gov (United States)

    Henkel, Steven; Pudlo, Dieter; Enzmann, Frieder; Reitenbach, Viktor; Albrecht, Daniel; Ganzer, Leonhard; Gaupp, Reinhard

    2016-06-01

    An essential part of the collaborative research project H2STORE (hydrogen to store), which is funded by the German government, was a comparison of various analytical methods for characterizing reservoir sandstones from different stratigraphic units. In this context Permian, Triassic and Tertiary reservoir sandstones were analysed. Rock core materials, provided by RWE Gasspeicher GmbH (Dortmund, Germany), GDF Suez E&P Deutschland GmbH (Lingen, Germany), E.ON Gas Storage GmbH (Essen, Germany) and RAG Rohöl-Aufsuchungs Aktiengesellschaft (Vienna, Austria), were processed by different laboratory techniques; thin sections were prepared, rock fragments were crushed and cubes of 1 cm edge length and plugs 3 to 5 cm in length with a diameter of about 2.5 cm were sawn from macroscopic homogeneous cores. With this prepared sample material, polarized light microscopy and scanning electron microscopy, coupled with image analyses, specific surface area measurements (after Brunauer, Emmet and Teller, 1938; BET), He-porosity and N2-permeability measurements and high-resolution microcomputer tomography (μ-CT), which were used for numerical simulations, were applied. All these methods were practised on most of the same sample material, before and on selected Permian sandstones also after static CO2 experiments under reservoir conditions. A major concern in comparing the results of these methods is an appraisal of the reliability of the given porosity, permeability and mineral-specific reactive (inner) surface area data. The CO2 experiments modified the petrophysical as well as the mineralogical/geochemical rock properties. These changes are detectable by all applied analytical methods. Nevertheless, a major outcome of the high-resolution μ-CT analyses and following numerical data simulations was that quite similar data sets and data interpretations were maintained by the different petrophysical standard methods. Moreover, the μ-CT analyses are not only time saving, but also non

  16. From Global Climate Model Projections to Local Impacts Assessments: Analyses in Support of Planning for Climate Change

    Science.gov (United States)

    Snover, A. K.; Littell, J. S.; Mantua, N. J.; Salathe, E. P.; Hamlet, A. F.; McGuire Elsner, M.; Tohver, I.; Lee, S.

    2010-12-01

    Assessing and planning for the impacts of climate change require regionally-specific information. Information is required not only about projected changes in climate but also the resultant changes in natural and human systems at the temporal and spatial scales of management and decision making. Therefore, climate impacts assessment typically results in a series of analyses, in which relatively coarse-resolution global climate model projections of changes in regional climate are downscaled to provide appropriate input to local impacts models. This talk will describe recent examples in which coarse-resolution (~150 to 300km) GCM output was “translated” into information requested by decision makers at relatively small (watershed) and large (multi-state) scales using regional climate modeling, statistical downscaling, hydrologic modeling, and sector-specific impacts modeling. Projected changes in local air temperature, precipitation, streamflow, and stream temperature were developed to support Seattle City Light’s assessment of climate change impacts on hydroelectric operations, future electricity load, and resident fish populations. A state-wide assessment of climate impacts on eight sectors (agriculture, coasts, energy, forests, human health, hydrology and water resources, salmon, and urban stormwater infrastructure) was developed for Washington State to aid adaptation planning. Hydro-climate change scenarios for approximately 300 streamflow locations in the Columbia River basin and selected coastal drainages west of the Cascades were developed in partnership with major water management agencies in the Pacific Northwest to allow planners to consider how hydrologic changes may affect management objectives. Treatment of uncertainty in these assessments included: using “bracketing” scenarios to describe a range of impacts, using ensemble averages to characterize the central estimate of future conditions (given an emissions scenario), and explicitly assessing

  17. Evaluation of fracture toughness of copper thin films by combining numerical analyses and experimental tests

    International Nuclear Information System (INIS)

    In this paper, a method of combining numerical analyses and experimental tests is used to evaluate fracture toughness of copper thin films of 15μm thickness. Far field loadings of a global local finite element model are inversely estimated by matching crack opening profiles in experiments with numerical results. The fracture toughness is then evaluated using the J integral for cracks in thin films under far field loadings. In experiments, Cu thin films attached to Aluminum sheets are loaded indirectly, and crack opening profiles are observed by microscope camera. Stress versus strain curves of Cu thin films are obtained through micro tensile tests, and the grain size of Cu thin films is observed by TEM analysis. The results show that the fracture toughness of Cu thin films with 500nm∼1μm sized grains is 6,962J/m'2'

  18. Numerical modeling of shoreline undulations part 1: Constant wave climate

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg; Fredsøe, Jørgen

    2013-01-01

    This paper presents a numerical study of the non-linear development of alongshore undulations up to fully developed quasi-steady equilibrium. A numerical model which describes the longshore sediment transport along arbitrarily shaped shorelines is applied, based on a spectral wave model, a depth...... integrated flow model, a wave-phase resolving sediment transport description and a one-line shoreline model.First the length of the shoreline undulations is determined in the linear regime using a stability analysis. Next the further evolution from the linear to the fully non-linear regime is described. In...

  19. Cyclic behavior of soils and numerical analyses in cold regions and seismic zones

    Institute of Scientific and Technical Information of China (English)

    Tadatsugu Tanaka

    2015-01-01

    The solutions of boundary value problems involving strain-softening material property contain serious difficulties from both modeling of strain-localization and a viewpoint of numerical procedure. Mesh size-dependent hardening modulus is considered to alleviate the mesh size-dependency of the solution. The elasto-plastic soil model with kinematic hardening model considering the cumulative deformation by cyclic loading is developed. In finite element analyses, the dynamic relaxation method combined with the generalized return-mapping algorithm is applied to the static drained and un-drained tri-axial tests and plane strain tests. The cyclic behavior of retaining wall problems by freeze and thaw in cold regions is also analyzed. Finally the dynamic progressive failure analysis of rockfill dam is carried out.

  20. Analytical and numerical analyses of an unconfined aquifer test considering unsaturated zone characteristics

    Science.gov (United States)

    Moench, A.F.

    2008-01-01

    A 7-d, constant rate aquifer test conducted by University of Waterloo researchers at Canadian Forces Base Borden in Ontario, Canada, is useful for advancing understanding of fluid flow processes in response to pumping from an unconfined aquifer. Measured data include not only drawdown in the saturated zone but also volumetric soil moisture measured at various times and distances from the pumped well. Analytical analyses were conducted with the model published in 2001 by Moench and colleagues, which allows for gradual drainage but does not include unsaturated zone characteristics, and the model published in 2006 by Mathias and Butler, which assumes that moisture retention and relative hydraulic conductivity (RHC) in the unsaturated zone are exponential functions of pressure head. Parameters estimated with either model yield good matches between measured and simulated drawdowns in piezometers. Numerical analyses were conducted with two versions of VS2DT: one that uses traditional Brooks and Corey functional relations and one that uses a RHC function introduced in 2001 by Assouline that includes an additional parameter that accounts for soil structure and texture. The analytical model of Mathias and Butler and numerical model of VS2DT with the Assouline model both show that the RHC function must contain a fitting parameter that is different from that used in the moisture retention function. Results show the influence of field-scale heterogeneity and suggest that the RHC at the Borden site declines more rapidly with elevation above the top of the capillary fringe than would be expected if the parameters were to reflect local- or core-scale soil structure and texture.

  1. Numerical and experimental analyses of the translation of bubbles due to non-spherical interface deformations

    Science.gov (United States)

    Igualada-Villodre, Elena; Fuster, Daniel; Rodríguez-Rodríguez, Javier; Dutilleul, Hugo

    2014-11-01

    Bubbles developing strong interface deformations (e.g. jetting) experience a strong net force that influences significantly their translational motion. In this work, the translation of bubbles as a result of non-spherical interface deformations is studied both numerically and experimentally. The Gerris flow solver is used to solve for a simplified model of the oscillation of a gas bubble in an incompressible liquid. In particular, we solve for the 3D conservation equations in both phases in a system where the total volume changes in the gas are imposed. Assuming a uniform pressure within the bubble, the conservation equations inside the bubble can be rewritten as a function of the temporal evolution of the bubble's volume. Thus, using volume change rates experimentally measured, we identify different regimes in which the bubble deformation induces a net translation velocity significantly larger than the one obtained with models assuming spherical symmetry. We explore the effect of three parameters: Weber number, dimensionless intensity of the pressure wave and relative distance of the source of the non-spherical perturbation. We support the conclusions extracted from the numerical analyses with experimental measurements of the bubble translational velocity exposed to shock waves.

  2. Analysing the vulnerability of buildings to climate change: Summer heat and flooding

    Directory of Open Access Journals (Sweden)

    Johannes Nikolowski

    2013-04-01

    Full Text Available The REGKLAM project (Development and Testing of an Integrated Regional Climate Change Adaption Programme for the Model Region Dresden forms part of the KLIMZUG programme (Managing Climate Change in the Regions for the Future funded by the German Federal Ministry of Education and Research. It is concerned with the adaptation of important sectors of the Dresden region to climate change. One aim is to investigate and where necessary reduce the vulnerability of buildings and settlement structures to changing climatic conditions. This paper looks at flood damage as an example for the potential of climate change impacts on buildings. In ex-post analyses and projections, the article presents the results of regional climatological studies. Interfaces between meteorology and civil engineering are discussed. On the basis of a typology of building stock in the region, the vulnerability of given building types to given impacts was analysed in the form of impact models. The examples of environmental causes chosen were summer heat and flooding. The paper concludes with a discussion of how buildings can be adapted to cope with the impacts described.

  3. PROGRESS IN THE STUDY OF RETROSPECTIVE NUMERICAL SCHEME AND THE CLIMATE PREDICTION

    Institute of Scientific and Technical Information of China (English)

    DONG Wenjie; CHOU Jieming; FENG Guolin

    2004-01-01

    The retrospective numerical scheme (RNS) is a numerical computation scheme designed for multiple past value problems of the initial value in mathematics and considering the selfmemory property of the system in physics. This paper briefly presents the historical background of RNS, elaborates the relation of the scheme with other difference schemes and other meteorological prediction methods, and introduces the application of RNS to the regional climatic self-memory model,simplified climate model, barotropic model, spectral model, and mesoscale model. At last, the paper sums up and points out the application perspective of the scheme and the direction for the future study.

  4. Analyses on the climate change responses over China under SRES B2 scenario using PRECIS

    Institute of Scientific and Technical Information of China (English)

    XU Yinlong; ZHANG Yong; LIN Erda; LIN Wantao; DONG Wenjie; Richard Jones; David Hassell; Simon Wilson

    2006-01-01

    The PRECIS, a regional climate model system developed at the UK Met Office Hadley Centre for Climate Prediction and Research, which is nested in one-way mode within the HadAM3P, a higher-resolution version of the atmospheric component of the Hadley Centre climate model HadCM3, is employed to simulate the baseline (1961-1990) climate for evaluation of model's capacity of simulating present climate and analyze the future climate change responses in the time-slice of 2071-2100 (2080s) under SRES B2 scenario over China relative to baseline average. It is indicated from the comparison of the simulated baseline climate with in situ observation that PRECIS can simulate the local distribution characteristics of surface air temperature over China quite well; generally speaking, the simulation for precipitation in the north of China and in winter is better than in the south of China and in summer, respectively; the simulation of precipitation in summer is sensitive to topography, and the simulated precipitation values are lower than observations over southeast coastal areas. It is shown from the analyses on the simulated climate change responses in 2080s under SRES B2 scenario relative to baseline that there would be an obvious surface air temperature increase in the north of China relative to that in the south of China, and especially in Northwest China and Northeast China, the amplitude of summer mean surface air temperature increments could reach 5℃; there would be an overall increase of the simulated precipitation in 2080s under SRES B2 scenario over most areas of China, while there would be significant precipitation decreases in South China in winter; there would be obvious precipitation decreases in Northeast China and North China in summer with high surface air temperature increase. However, it presents an obvious precipitation increase over the middle and lower reaches of the Yangtze River in summer.

  5. Stable carbon isotope analyses in sediments and its implications for reconstructing climatic and environmental changes

    International Nuclear Information System (INIS)

    The relative significance of the 20th-century climatic and environmental changes must be assessed form the long-term global-scale perspective available from a spectrum of proxy histories. In many cases geochemical proxies in sediments are needed to supplement the established use of the stable isotope analyses for paleotemperature and paleo-hydrological modeling so as to understand the past environment conditions and evaluate predictive models of climate. The stable carbon isotope fractionation during photosynthesis and the system CO2 (gas)-CO2-(aqueous)-HCO3- (aqueous) are reviewed; and application of the stable carbon isotope to reconstruction of palaeo-climatic and palaeo-environmental changes, especially CO2 levels during the late Quaternary are discussed

  6. Numerical Modeling for Flood Mapping under Climate Change Impacts: Transboundary Dniester River Study

    Science.gov (United States)

    Zheleznyak, Mark; Kolomiets, Pavlo; Dzjuba, Natalia; Ievgen, Ievgen; Sorokin, Maxim; Denisov, Nickolai; Ischuk, Oleksiy; Koeppel, Sonja

    2015-04-01

    The Dniester river is shared by Ukraine and Moldova. Ukraine being both upstream and downstream of Moldova. The basin is especially suffering from heavy floods, often with transboundary impacts: in Ukraine, disastrous floods in July 2008, which were possibly partly caused or exacerbated by climate change. Within the UNECE | ENVSEC project "Reducing vulnerability to extreme floods and climate change in the Dniester river basin" the numerical flood risks mapping for several "hot spots" along the Dniester river was initiated Two transboundary sites: "Mohyliv Podylskiy- Ataki" and "Dubossary HPP-, Mayaki" (in the delta zone) were chosen for flood risk modelling/mapping. . Floodplain inundation at Mohyliv Podylskiy- Ataki during historical and projected extreme floods scenarios is simulated by 2D model COASTOX -UN based on the numerical solution of shallow water equations on unstructured grid. The scenario of extreme flood, July 2008 that caused hazardous flooding of the riverside areas of Mohyliv Podylskiy has been used for model verification and calibration. The floodmarks of the inundated in 2008 streets have been collected and GIS processed to be used together with the data from the city's water gage station for model testing. The comparison of the simulated dynamics of floodplain inundation during 2008 flood with the observed data show good accuracy of the model. The technologies of the flood modeling and GIS based risk assessments verified for this site are implemented for analyses of the vulnerability to extreme floods for Q=7600 m3 / sec inflow to Dniester reservoir ( 1% flood for contemporary climate assessment) and for Q=8700 m3 / sec. that is considered as projection of 1% flood maximum for XXI century The detailed flood mapping was provided for all cases and was shown that 13% increase in water elevation for future extreme flood scenario will provide at 20% increasing of flooded areas in Mohilev Podolsky. For the site Dubossary NPP in Moldova downstream till

  7. Numerical simulations and analyses of temperature control loop heat pipe for space CCD camera

    Science.gov (United States)

    Meng, Qingliang; Yang, Tao; Li, Chunlin

    2016-10-01

    As one of the key units of space CCD camera, the temperature range and stability of CCD components affect the image's indexes. Reasonable thermal design and robust thermal control devices are needed. One kind of temperature control loop heat pipe (TCLHP) is designed, which highly meets the thermal control requirements of CCD components. In order to study the dynamic behaviors of heat and mass transfer of TCLHP, particularly in the orbital flight case, a transient numerical model is developed by using the well-established empirical correlations for flow models within three dimensional thermal modeling. The temperature control principle and details of mathematical model are presented. The model is used to study operating state, flow and heat characteristics based upon the analyses of variations of temperature, pressure and quality under different operating modes and external heat flux variations. The results indicate that TCLHP can satisfy the thermal control requirements of CCD components well, and always ensure good temperature stability and uniformity. By comparison between flight data and simulated results, it is found that the model is to be accurate to within 1°C. The model can be better used for predicting and understanding the transient performance of TCLHP.

  8. Thermal-hydraulics numerical analyses of Pebble Bed Advanced High Temperature Reactor hot channel

    International Nuclear Information System (INIS)

    Background: The thermal hydraulics behavior of the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) hot channel was studied. Purpose: We aim to analyze the thermal-hydraulics behavior of the PB-AHTR, such as pressure drop, temperature distribution of coolant and pebble bed as well as thermal removal capacity in the condition of loss of partial coolant. Methods: We used a modified FLUENT code which was coupled with a local non-equilibrium porous media model by introducing a User Defined Scalar (UDS) in the calculation domain of the reactor core and subjoining different resistance terms (Ergun and KTA) to calculate the temperature of coolant, solid phase of pebble bed and pebble center in the core. Results: Computational results showed that the resistance factor has great influence on pressure drop and velocity distribution, but less impact on the temperature of coolant, solid phase of pebble bed and pebble center. We also confirmed the heat removal capacity of the PB-AHTR in the condition of nominal and loss of partial coolant conditions. Conclusion: The numerical analyses results can provide a useful proposal to optimize the design of PB-AHTR. (authors)

  9. The Sahel Region of West Africa: Examples of Climate Analyses Motivated By Drought Management Needs

    Science.gov (United States)

    Ndiaye, O.; Ward, M. N.; Siebert, A. B.

    2011-12-01

    The Sahel is one of the most drought-prone regions in the world. This paper focuses on climate sources of drought, and some new analyses mostly driven by users needing climate information to help in drought management strategies. The Sahel region of West Africa is a transition zone between equatorial climate and vegetation to the south, and desert to the north. The climatology of the region is dominated by dry conditions for most of the year, with a single peak in rainfall during boreal summer. The seasonal rainfall total contains both interannual variability and substantial decadal to multidecadal variability (MDV). This brings climate analysis and drought management challenges across this range of timescales. The decline in rainfall from the wet decades of the 1950s and 60s to the dry decades of the 1970s and 80s has been well documented. In recent years, a moderate recovery has emerged, with seasonal totals in the period 1994-2010 significantly higher than the average rainfall 1970-1993. These MDV rainfall fluctuations have expression in large-scale sea-surface temperature fluctuations in all ocean basins, placing the changes in drought frequency within broader ocean-atmosphere climate fluctuation. We have evaluated the changing character of low seasonal rainfall total event frequencies in the Sahel region 1950-2010, highlighting the role of changes in the mean, variance and distribution shape of seasonal rainfall totals as the climate has shifted through the three observed phases. We also consider the extent to which updating climate normals in real-time can damp the bias in expected event frequency, an important issue for the feasibility of index insurance as a drought management tool in the presence of a changing climate. On the interannual timescale, a key factor long discussed for agriculture is the character of rainfall onset. An extended dry spell often occurs early in the rainy season before the crop is fully established, and this often leads to crop

  10. Influence of external climate forcing on coastal upwelling systems analysed in ensemble of past millennium climate simulations

    Science.gov (United States)

    Tim, Nele; Zorita, Eduardo; Hünicke, Birgit; Yi, Xin; Emeis, Kay

    2016-04-01

    Eastern Boundary Upwelling Systems are highly productive coastal ocean areas where nutrient rich, cold water upwells by the action of favorable winds. Observations over the 20th century and ocean sediment records, which may be indicative of upwelling, display an intensification due to stronger external climate forcing, such as increasing greenhouse gas concentrations or changes in solar irradiance. This intensification is compatible with the hypothesis put forward by Bakun (1990) that a stronger external radiative forcing should lead to a more intense coastal upwelling. Here, we analyze ensemble of simulations covering the past millennium with the aim of identifying and quantifying the role of external climate forcing on upwelling in the major Eastern Boundary Upwelling System. We analyse the decadal variability and centennial trends of upwelling in ensemble of simulations with the global climate model MPI-ESM covering the past millennium, the last 150 years and the next 100 years. The future simulations were driven by three IPCC scenarios of concentrations of anthropogenic greenhouse gases, RCP2.5, RCP4.5 and RCP 8.5. For the past millennium and the last 150 years, coastal upwelling does not show any imprint of external forcing. This result indicates that chaotic internal variability has dominated upwelling intensity in major upwelling regions over the last thousand years and even since industrialisation up to present. For the 21st century, all ensemble members show a consistent and significant intensification of upwelling in the strongest scenario RCP8.5 for the Benguela upwelling region, consistent and significant weakening for Morocco and California, and no significant change for the Peruvian upwelling. Weaker scenarios do not produce consistent long-term trends that are replicated in all ensemble members. The results are confirmed by analysing another ensemble of past millennium simulations with the model CESM-CAM5 (Community Earth System Model

  11. Estimation of the mean depth of boreal lakes for use in numerical weather prediction and climate modelling

    Directory of Open Access Journals (Sweden)

    Margarita Choulga

    2014-03-01

    Full Text Available Lakes influence the structure of the atmospheric boundary layer and, consequently, the local weather and local climate. Their influence should be taken into account in the numerical weather prediction (NWP and climate models through parameterisation. For parameterisation, data on lake characteristics external to the model are also needed. The most important parameter is the lake depth. Global database of lake depth GLDB (Global Lake Database is developed to parameterise lakes in NWP and climate modelling. The main purpose of the study is to upgrade GLDB by use of indirect estimates of the mean depth for lakes in boreal zone, depending on their geological origin. For this, Tectonic Plates Map, geological, geomorphologic maps and the map of Quaternary deposits were used. Data from maps were processed by an innovative algorithm, resulting in 141 geological regions where lakes were considered to be of kindred origin. To obtain a typical mean lake depth for each of the selected regions, statistics from GLDB were gained and analysed. The main result of the study is a new version of GLDB with estimations of the typical mean lake depth included. Potential users of the product are NWP and climate models.

  12. Interaction Between Typhoon and Western Pacific Subtropical Anticyclone:Data Analyses and Numerical Experiments

    Institute of Scientific and Technical Information of China (English)

    Ren Suling; LIU Yimin; WU Guoxiong

    2008-01-01

    Three kinds of typhoons with distinct tracks are sorted based on a set of typhoon data from 1958 to 1998.The results of composite analyses confirln that difierent typhoon tracks correspond to ditierent patterns of the subtropical anticyclone over the western Pacific(SAWP).When the tracks are westward,the SAWP is strong,with a zonal form,and stretches westward;when the tracks are recurring,the main body of the SAWP shifts eastward and breaks near 160°E;and When the tracks are northward,the SAWP is located far east of its normal position.Based on the above result,two different initial fields are configured,one has a zonal and strong SAWP,and the other has a meridional and weak SAWP.By using the GOALS R42L9 climate model,a temperature disturbance is added into these two difierent initial fields to force the formation of a typhoon.Westward and northward tracked typhoons are well simulated,thus verifying that different patterns of the SAWP have different effects on typhoon tracks.Results also show that typhoons can induce barotropic Rossby waves propagating to the mid and high latitudes.Under different background zonal flows,the wave trains triggered by the typhoons of westward and northward tracks are also different,and their effects on the mid and high latitude circulations and the SAWP are difierent.Compared to a northward tracked typhoon,a westward tracked typhoon is able to induce positive geopotential height anomaly to its north and northwest,resulting in the SAWP strengthening and developing westward.

  13. Simulating infectious disease risk based on climatic drivers: from numerical weather prediction to long term climate change scenario

    Science.gov (United States)

    Caminade, C.; Ndione, J. A.; Diallo, M.; MacLeod, D.; Faye, O.; Ba, Y.; Dia, I.; Medlock, J. M.; Leach, S.; McIntyre, K. M.; Baylis, M.; Morse, A. P.

    2012-04-01

    Climate variability is an important component in determining the incidence of a number of diseases with significant health and socioeconomic impacts. In particular, vector born diseases are the most likely to be affected by climate; directly via the development rates and survival of both the pathogen and the vector, and indirectly through changes in the surrounding environmental conditions. Disease risk models of various complexities using different streams of climate forecasts as inputs have been developed within the QWeCI EU and ENHanCE ERA-NET project frameworks. This work will present two application examples, one for Africa and one for Europe. First, we focus on Rift Valley fever over sub-Saharan Africa, a zoonosis that affects domestic animals and humans by causing an acute fever. We show that the Rift Valley fever outbreak that occurred in late 2010 in the northern Sahelian region of Mauritania might have been anticipated ten days in advance using the GFS numerical weather prediction system. Then, an ensemble of regional climate projections is employed to model the climatic suitability of the Asian tiger mosquito for the future over Europe. The Asian tiger mosquito is an invasive species originally from Asia which is able to transmit West Nile and Chikungunya Fever among others. This species has spread worldwide during the last decades, mainly through the shipments of goods from Asia. Different disease models are employed and inter-compared to achieve such a task. Results show that the climatic conditions over southern England, central Western Europe and the Balkans might become more suitable for the mosquito (including the proviso that the mosquito has already been introduced) to establish itself in the future.

  14. Simulation of the world ocean climate with a massively parallel numerical model

    Science.gov (United States)

    Ushakov, K. V.; Ibrayev, R. A.; Kalmykov, V. V.

    2015-07-01

    The INM-IO numerical World Ocean model is verified through the calculation of the model ocean climate. The numerical experiment was conducted for a period of 500 years following the CORE-I protocol. We analyze some basic elements of the large-scale ocean circulation and local and integral characteristics of the model solution. The model limitations and ways they are overcome are described. The results generally fit the level of leading models. This experiment is a necessary step preceding the transition to high-resolution diagnostic and prognostic calculations of the state of the World Ocean and its individual basins.

  15. Combined analytical and numerical approaches in Dynamic Stability analyses of engineering systems

    Science.gov (United States)

    Náprstek, Jiří

    2015-03-01

    Dynamic Stability is a widely studied area that has attracted many researchers from various disciplines. Although Dynamic Stability is usually associated with mechanics, theoretical physics or other natural and technical disciplines, it is also relevant to social, economic, and philosophical areas of our lives. Therefore, it is useful to occasionally highlight the general aspects of this amazing area, to present some relevant examples and to evaluate its position among the various branches of Rational Mechanics. From this perspective, the aim of this study is to present a brief review concerning the Dynamic Stability problem, its basic definitions and principles, important phenomena, research motivations and applications in engineering. The relationships with relevant systems that are prone to stability loss (encountered in other areas such as physics, other natural sciences and engineering) are also noted. The theoretical background, which is applicable to many disciplines, is presented. In this paper, the most frequently used Dynamic Stability analysis methods are presented in relation to individual dynamic systems that are widely discussed in various engineering branches. In particular, the Lyapunov function and exponent procedures, Routh-Hurwitz, Liénard, and other theorems are outlined together with demonstrations. The possibilities for analytical and numerical procedures are mentioned together with possible feedback from experimental research and testing. The strengths and shortcomings of these approaches are evaluated together with examples of their effective complementing of each other. The systems that are widely encountered in engineering are presented in the form of mathematical models. The analyses of their Dynamic Stability and post-critical behaviour are also presented. The stability limits, bifurcation points, quasi-periodic response processes and chaotic regimes are discussed. The limit cycle existence and stability are examined together with their

  16. Constraint envelope analyses of macroecological patterns reveal climatic effects on Pleistocene mammal extinctions

    Science.gov (United States)

    Lima-Ribeiro, Matheus S.; Hortal, Joaquín; Varela, Sara; Diniz-Filho, José Alexandre F.

    2014-07-01

    Quantitative analysis of macroecological patterns for late Pleistocene assemblages can be useful for disentangling the causes of late Quaternary extinctions (LQE). However, previous analyses have usually assumed linear relationships between macroecological traits, such as body size and range size/range shift, that may have led to erroneous interpretations. Here, we analyzed mammalian datasets to show how macroecological patterns support climate change as an important driver of the LQE, which is contrary to previous analyses that did not account for more complex relationships among traits. We employed quantile regression methods that allow a detailed and fine-tuned quantitative analysis of complex macroecological patterns revealed as polygonal relationships (i.e., constraint envelopes). We showed that these triangular-shaped envelopes that describe the macroecological relationship between body size and geographical range shift reflect nonrandom extinction processes under which the large-bodied species are more prone to extinction during events of severe habitat loss, such as glacial/interglacial transitions. Hence, we provide both a theoretical background and methodological framework to better understand how climate change induces body size-biased species sorting and shapes complex macroecological patterns.

  17. Analysing bifurcations encountered in numerical modelling of current transfer to cathodes of dc glow and arc discharges

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P G C; Benilov, M S; Cunha, M D; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2009-10-07

    Bifurcations and/or their consequences are frequently encountered in numerical modelling of current transfer to cathodes of gas discharges, also in apparently simple situations, and a failure to recognize and properly analyse a bifurcation may create difficulties in the modelling and hinder the understanding of numerical results and the underlying physics. This work is concerned with analysis of bifurcations that have been encountered in the modelling of steady-state current transfer to cathodes of glow and arc discharges. All basic types of steady-state bifurcations (fold, transcritical, pitchfork) have been identified and analysed. The analysis provides explanations to many results obtained in numerical modelling. In particular, it is shown that dramatic changes in patterns of current transfer to cathodes of both glow and arc discharges, described by numerical modelling, occur through perturbed transcritical bifurcations of first- and second-order contact. The analysis elucidates the reason why the mode of glow discharge associated with the falling section of the current-voltage characteristic in the solution of von Engel and Steenbeck seems not to appear in 2D numerical modelling and the subnormal and normal modes appear instead. A similar effect has been identified in numerical modelling of arc cathodes and explained.

  18. Numerical and experimental analyses of resin infusion manufacturing processes of composite materials

    CERN Document Server

    Wang, Peng; Molimard, Jérôme; Vautrin, Alain; Minni, Jean-Christophe; 10.1177/0021998311421990

    2012-01-01

    Liquid resin infusion (LRI) processes are promising manufacturing routes to produce large, thick, or complex structural parts. They are based on the resin flow induced, across its thickness, by a pressure applied onto a preform/resin stacking. However, both thickness and fiber volume fraction of the final piece are not well controlled since they result from complex mechanisms which drive the transient mechanical equilibrium leading to the final geometrical configuration. In order to optimize both design and manufacturing parameters, but also to monitor the LRI process, an isothermal numerical model has been developed which describes the mechanical interaction between the deformations of the porous medium and the resin flow during infusion.1, 2 With this numerical model, it is possible to investigate the LRI process of classical industrial part shapes. To validate the numerical model, first in 2D, and to improve the knowledge of the LRI process, this study details a comparison between numerical simulations and...

  19. Global terrestrial water storage connectivity revealed using complex climate network analyses

    Directory of Open Access Journals (Sweden)

    A. Y. Sun

    2015-04-01

    Full Text Available Terrestrial water storage (TWS exerts a key control in global water, energy, and biogeochemical cycles. Although certain causal relationships exist between precipitation and TWS, the latter also reflects impacts of anthropogenic activities. Thus, quantification of the spatial patterns of TWS will not only help to understand feedbacks between climate dynamics and hydrologic cycle, but also provide new model calibration constraints for improving the current land surface models. In this work, the connectivity of TWS is quantified using the climate network theory, which has received broad attention in the climate modeling community in recent years. Complex networks of TWS anomalies are built using two global TWS datasets, a remote-sensing product that is obtained from the Gravity Recovery and Climate Experiment (GRACE satellite mission, and a model-generated dataset from the global land data assimilation system's NOAH model (GLDAS-NOAH. Both datasets have 1 ° × 1 ° resolutions and cover most global land areas except for permafrost regions. TWS networks are built by first quantifying pairwise correlation among all valid TWS anomaly time series, and then applying a statistical cutoff threshold to retain only the most important features in the network. Basinwise network connectivity maps are used to illuminate connectivity of individual river basins with other regions. The constructed network degree centrality maps show TWS hotspots around the globe and the patterns are consistent with recent GRACE studies. Parallel analyses of networks constructed using the two datasets indicate that the GLDAS-NOAH model captures many of the spatial patterns shown by GRACE, although significant discrepancies exist in some regions. Thus, our results provide important insights for constraining land surface models, especially in data sparse regions.

  20. NUMERICAL SIMULATION ANALYSES ON REINFORCEMENT FUNCTION OF THE TENSIONED AND GROUTED BOLTS

    Institute of Scientific and Technical Information of China (English)

    邹喜正; 李华祥

    1998-01-01

    The purpose of the paper is to calculate the equivalent mechanics parameters of reinforced surroundings, which is based on the assume that the reinforcement of bolts is equivalent to the improvement of mechanics parameters of surroundings and combines with site engineering practice. Use numerical simulation analysis to study the reinforcement mechanism of full length bolts, thus to provide theoretical bases for bolting design.

  1. Numerical andexperimental analyses of hydrodynamic performance of a cha- nnel type planing trimaran

    Institute of Scientific and Technical Information of China (English)

    SU Yu-min; WANG Shuo; SHEN Hai-long; DUXin

    2014-01-01

    This paper studies the hydrodynamic performance of a channel type planing trimaran. A numerical simulation is carried out based on a RANS-VOF solver to analyze the hydrodynamic performance of the channel type planing trimaran. A series of hydrodynamic experiments in towing tank were carried out, in which both the running attitude and the resistance performance of the trimaran model were recorded. Some hydrodynamic characteristics of the channel type planning trimaran are shown by the results. Firstly, the resistance declines significantly, with the forward speed across the high-speed resistance peak due to the combined effects of the aerodynamic and hydrodynamic lifts. Secondly, the resistance performance is influenced markedly by the longitudinal positio- ns of centre of the gravity and the displacements. Besides, the pressure distribution on the hull and the two-phase flow in the channel are discussed in the numerical simulations.

  2. Experimental and Numerical Analyses of New Massive Wooden Shear-Wall Systems

    Directory of Open Access Journals (Sweden)

    Luca Pozza

    2014-07-01

    Full Text Available Three innovative massive wooden shear-wall systems (Cross-Laminated-Glued Wall, Cross-Laminated-Stapled Wall, Layered Wall with dovetail inserts were tested and their structural behaviour under seismic action was assessed with numerical simulations. The wall specimens differ mainly in the method used to assemble the layers of timber boards composing them. Quasi-static cyclic loading tests were carried out and then reproduced with a non-linear numerical model calibrated on the test results to estimate the most appropriate behaviour factor for each system. Non-linear dynamic simulations of 15 artificially generated seismic shocks showed that these systems have good dissipative capacity when correctly designed and that they can be assigned to the medium ductility class of Eurocode 8. This work also shows the influence of deformations in wooden panels and base connectors on the behaviour factor and dissipative capacity of the system.

  3. Physical mechanisms involved in grooved flat heat pipes: experimental and numerical analyses

    OpenAIRE

    Lips, S.; Lefevre, F.; Bonjour, J.

    2011-01-01

    An experimental database, obtained with flat plate heat pipes (FPHP) with longitudinal grooves is presented. The capillary pressure measured by confocal microscopy and the temperature field in the wall are presented in various experimental conditions (vapour space thickness, filing ratio, heat transfer rate, tilt angle, fluid). Coupled hydrodynamic and thermal models are developed. Experimental results are compared to results of numerical models. Physical mechanisms involved in grooved heat p...

  4. Numerical analyses of the effect of SG‐interlayer shear stiffness on the structural performance of reinforced glass beams

    DEFF Research Database (Denmark)

    Louter, C.; Nielsen, Jens Henrik

    2013-01-01

    -interlayers and the reinforcement are incorporated. In the model, the glass parts are allowed to crack, but all other parts are assumed linear elastic throughout the analyses. By changing the shear modulus of the SG-interlayer in multiple analyses, its contribution to the overall structural performance of the beams – especially......This paper focuses on the numerical modelling of SentryGlas-laminated reinforced glass beams. In these beams, which have been experimentally investigated in preceding research, a stainless steel reinforcement section is laminated at the inner recessed edge of a triple-layer glass beam by means...... of SentryGlas (SG) interlayer sheets. The current contribution numerically investigates the effect of the SG-interlayer shear stiffness on the overall structural response of the beams. This is done by means of a 3D finite element model in which the individual glass layers, the SG...

  5. Numerical analyses of the effect of SG-interlayer shear stiffness on the structural performance of reinforced glass beams

    DEFF Research Database (Denmark)

    Louter, C.; Nielsen, Jens Henrik

    2013-01-01

    -interlayers and the reinforcement are incorporated. In the model, the glass parts are allowed to crack, but all other parts are assumed linear elastic throughout the analyses. By changing the shear modulus of the SG-interlayer in multiple analyses, its contribution to the overall structural performance of the beams - especially......This paper focuses on the numerical modelling of SentryGlas-laminated reinforced glass beams. In these beams, which have been experimentally investigated in preceding research, a stainless steel reinforcement section is laminated at the inner recessed edge of a triple-layer glass beam by means...... of SentryGlas (SG) interlayer sheets. The current contribution numerically investigates the effect of the SG-interlayer shear stiffness on the overall structural response of the beams. This is done by means of a 3D finite element model in which the individual glass layers, the SG...

  6. Retrieval of temperature profiles from CHAMP for climate monitoring: intercomparison with Envisat MIPAS and GOMOS and different atmospheric analyses

    Directory of Open Access Journals (Sweden)

    A. Gobiet

    2007-02-01

    temperature or pressure value derived from meteorological analyses is prone to introduce biases from the initialisation data to the retrieved temperatures down to below 25 km. Above 30 to 35 km, GNSS RO delivers a considerable amount of observed information up to around 40 km, which is particularly interesting for numerical weather prediction (NWP systems, where direct assimilation of non-initialized (a priori-free observed RO bending angles is thus the method of choice. The results underline the value of RO for climate applications.

  7. Sub-grid Parameterization of Cumulus Vertical Velocities for Climate and Numerical Weather Prediction Models

    Science.gov (United States)

    Cooke, William; Donner, Leo

    2015-04-01

    Microphysical and aerosol processes determine the magnitude of climate forcing by aerosol-cloud interactions, are central aspects of cloud-climate feedback, and are important elements in weather systems for which accurate forecasting is a major goal of numerical weather prediction. Realistic simulation of these processes demands not only accurate microphysical and aerosol process representations but also realistic simulation of the vertical motions in which the aerosols and microphysics act. Aerosol activation, for example, is a strong function of vertical velocity. Cumulus parameterizations for climate and numerical weather prediction models have recently begun to include vertical velocities among the statistics they predict. These vertical velocities have been subject to only limited evaluation using observed vertical velocities. Deployments of multi-Doppler radars and dual-frequency profilers in recent field campaigns have substantially increased the observational base of cumulus vertical velocities, which for decades had been restricted mostly to GATE observations. Observations from TWP-ICE (Darwin, Australia) and MC3E (central United States) provide previously unavailable information on the vertical structure of cumulus vertical velocities and observations in differing synoptic contexts from those available in the past. They also provide an opportunity to independently evaluate cumulus parameterizations with vertical velocities tuned to earlier GATE observations. This presentation will compare vertical velocities observed in TWP-ICE and MC3E with cumulus vertical velocities using the parameterization in the GFDL CM3 climate model. Single-column results indicate parameterized vertical velocities are frequently greater than observed. Errors in parameterized vertical velocities exhibit similarities to vertical velocities explicitly simulated by cloud-system resolving models, and underlying issues in the treatment of microphysics may be important for both. The

  8. The Virtual Institute of Integrated Climate and Landscape Evolution Analyses - ICLEA

    Science.gov (United States)

    Schwab, Markus; Brauer, Achim; Błaszkiewicz, Mirosław; Raab, Thomas; Wilmking, Martin; Blume, Theresa; Iclea Team

    2014-05-01

    The GFZ, Greifswald University and the Brandenburg University of Technology together with their partner the Polish Academy of Sciences strive for focusing their research capacities and expertise in a Helmholtz Virtual Institute for Integrated Climate and Landscape Evolution Analyses (ICLEA). The Coordination Team is based at the GFZ in Potsdam and consists of a permanent scientific manager and administrative personnel. ICLEA offers young researchers an interdisciplinary and structured education and promote their early independence through coaching and mentoring. Postdoctoral rotation positions at the ICLEA partner institutions ensure mobility of young researchers and promote dissemination of information and expertise between disciplines. Training, Research and Analytical workshops between research partners of the ICLEA virtual institute are another important measure to qualify young researchers. The long-term mission of the Virtual Institute is to provide a substantiated data basis for sustained environmental maintenance based on a profound process understanding at all relevant time scales. Aim is to explore processes of climate and landscape evolution in an historical cultural landscape extending from northeastern Germany into northwestern Poland. The northern-central European lowlands will be facilitated as a natural laboratory providing an ideal case for utilizing a systematic and holistic approach. In ICLEA five complementary work packages (WP) are established according to the key research aspects. WP 1 focus on monitoring mainly hydrology and soil moisture as well as meteorological parameters. WP 2 is linking present day and future monitoring data with the most recent past through analysing satellite images. This WP will further provide larger spatial scales. WP 3-5 focus on different natural archives to obtain a broad variety of high quality proxy data. Tree rings provide sub-seasonal data for the last centuries up to few millennia, varved lake sediments

  9. Numerical Experiments on the Spin-up Time for Seasonal-Scale Regional Climate Modeling

    Institute of Scientific and Technical Information of China (English)

    ZHONG Zhong; HU Yijia; MIN Jinzhong; XU Honglei

    2007-01-01

    In this paper, the numerical experiments on the issue of spin-up time for seasonal-scale regional climate modeling were conducted with the newly Regional Climate Model (RegCM3), in the case of the abnormal climate event during the summer of 1998 in China. To test the effect of spin-up time on the regional climate simulation results for such abnormal climate event, a total of 11 experiments were performed with different spin-up time from 10 days to 6 months, respectively. The simulation results show that, for the meteorological variables in the atmosphere, the model would be running in "climate mode" after 4-8-day spin-up time, then,it is independent of the spin-up time basically, and the simulation errors are mainly caused by the model's failure in describing the atmospheric processes over the model domain. This verifies again that the regional climate modeling is indeed a lateral boundary condition problem as demonstrated by earlier research work.The simulated mean precipitation rate over each subregion is not sensitive to the spin-up time, but the precipitation scenario is somewhat different for the experiment with different spin-up time, which shows that there exists the uncertainty in the simulation to precipitation scenario, and such a uncertainty exhibits more over the areas where heavy rainfall happened. Generally, for monthly-scale precipitation simulation, aspin-up time of 1 month is enough, whereas a spin-up time of 2 months is better for seasonal-scale one.Furthermore, the relationship between the precipitation simulation error and the advancement/withdrawal of East Asian summer monsoon was analyzed. It is found that the variability of correlation coefficient for precipitation is more significant over the areas where the summer monsoon is predominant. Therefore, the model's capability in reproducing precipitation features is related to the heavy rainfall processes associated with the advancement/withdrawal of East Asian summer monsoon, which suggests

  10. Influence of Impeller Geometry on the Unsteady Flow in a Centrifugal Fan: Numerical and Experimental Analyses

    Directory of Open Access Journals (Sweden)

    M. Younsi

    2007-01-01

    Full Text Available The aim of this study is to evaluate the influence of design parameters on the unsteady flow in a forward-curved centrifugal fan and their impact on the aeroacoustic behavior. To do so, numerical and experimental studies have been carried out on four centrifugal impellers designed with various geometrical parameters. The same volute casing has been used to study these impellers. The effects on the unsteady flow behavior related to irregular blade spacing, blade count and radial distance between the impeller periphery and the volute tongue have been studied. The numerical simulations of the unsteady flow have been carried out using computational fluid dynamics (CFD tools based on the unsteady Reynolds averaged Navier Stokes (URANS approach. The study is focused on the unsteadiness induced by the aerodynamic interaction between the volute and the rotating impeller blades. In order to predict the acoustic pressure at far field, the unsteady flow variables provided by the CFD calculations have been used as inputs in the Ffowcs Williams-Hawkings equations (FW-H. The experimental part of this work concerns measurement of aerodynamic performance of the fans using a test bench built according to ISO 5801 (1997 standard. In addition to this, pressure microphones have been flush mounted on the volute tongue surface in order to measure the wall pressure fluctuations. The sound pressure level (SPL measurements have been carried out in an anechoic room in order to remove undesired noise reflections. Finally, the numerical results have been compared with the experimental measurements and a correlation between the wall pressure fluctuations and the far field noise signals has been found.

  11. Numerical analyses on cooling process of superconducting insertion quadrupole magnets for BEPC II

    International Nuclear Information System (INIS)

    A pair of superconducting insertion quadrupole magnets (SCQ), and a superconducting solenoid magnets (SSM) were used in the Beijing Electron-Positron Collider Upgrade (BEPC II) in order to reduce the length of the beam, and to increase distinguish and identification ability of the particle. A cryogenic plant of 500 W at 4.5 K was to be built for the operation of the superconducting magnets. The paper described the cooling process for the SCQ and SSM magnets. Two kinds of cooling schemes for SCQ magnets, supercritical helium cooling and subcooled liquid helium cooling, were compared by numerical method. Thermal parameters of two kinds of cooling process were provided. Finally, the design of the subcooler, one of key components was presented. (authors)

  12. Numerical analyses of pressure fluctuations induced by interblade vortices in a model Francis turbine

    Institute of Scientific and Technical Information of China (English)

    左志钢; 刘树红; 刘德民; 覃大清; 吴玉林

    2015-01-01

    Interblade vortices can greatly influence the stable operations of Francis turbines. As visible interblade vortices are essentially cavitating flows, i.e., the ones to cause interblade vortex cavitations, an unsteady simulation with a method using the RNG k-εturbulence model and the Zwart-Gerber-Belamri (ZGB) cavitation model is carried out to predict the pressure fluctuations induced. Modifications of the turbulence viscosity are made to improve the resolutions. The interblade vortices of two different appearances are observed from the numerical results, namely, the columnar and streamwise vortices, as is consistent with the experimental results. The pressure fluctuations of different frequencies are found to be induced by the interblade vortices on incipient and developed interblade vortex lines, respectively, on the Hill diagram of the model runner’s parameters. From the centrifugal Rayleigh instability criterion, it follows that the columnar interblade vortices are stable and the streamwise interblade vortices are unstable in the model Francis turbine.

  13. Qualitative and numerical analyses of the effects of river inflow variations on mixing diagrams in estuaries

    Science.gov (United States)

    Cifuentes, L.A.; Schemel, L.E.; Sharp, J.H.

    1990-01-01

    The effects of river inflow variations on alkalinity/salinity distributions in San Francisco Bay and nitrate/salinity distributions in Delaware Bay are described. One-dimensional, advective-dispersion equations for salinity and the dissolved constituents are solved numerically and are used to simulate mixing in the estuaries. These simulations account for time-varying river inflow, variations in estuarine cross-sectional area, and longitudinally varying dispersion coefficients. The model simulates field observations better than models that use constant hydrodynamic coefficients and uniform estuarine geometry. Furthermore, field observations and model simulations are consistent with theoretical 'predictions' that the curvature of propery-salinity distributions depends on the relation between the estuarine residence time and the period of river concentration variation. ?? 1990.

  14. Numerical analyses of influence of overlying pit excavation on existing tunnels

    Institute of Scientific and Technical Information of China (English)

    郑刚; 魏少伟

    2008-01-01

    The response of existing tunnel due to overlying excavation was studied using 2D FEM (Finite element method). Three typical locations of tunnel with respect to excavation, namely at the central line under the excavation bottom, directly under the base of diaphragm wall and outside of diaphragm, were considered. The variation of tunnel response with the change of location of tunnel was analyzed. The stress path of soil surrounding tunnel during the process of excavation was compared. Numerical analysis results indicate that the underlying tunnels at different locations under the excavation will experience convergence and divergence due to overlying excavation. Moreover, the tunnel located below base of diaphragm wall will experience distortion. The deformation is mainly due to the uneven changes of ground contact pressure on tunnel linings. Both the vertical and horizontal displacement of the tunnel decrease with the increase of the tunnel embedded depth beneath the formation of excavation.

  15. Numerical analyses of a water pool under loadings caused by a condensation induced water hammer

    Energy Technology Data Exchange (ETDEWEB)

    Timperi, A.; Paettikangas, T.; Calonius, K.; Tuunanen, J.; Poikolainen, J.; Saarenheimo, A. [VTT Industrial Systems (Finland)

    2004-03-01

    Three-dimensional simulations of a rapidly condensing steam bubble in a water pool have been performed by using the commercial computational fluid dynamics (CFD) code Star-CD. The condensing bubble was modelled by using a mass sink in a single-phase calculation. The pressure load on the wall of the pool was determined and transferred to the structural analyses code ABAQUS. The analyses were done for a test pool at Lappeenranta University of Technology. The structural integrity of the pool during steam experiments was investigated by assuming as a test load the rapid condensation of a steam bubble with a diameter of 20 cm. The mass sink for modelling the collapse of the bubble was deter-mined from the potential theory of incompressible fluid. The rapid condensation of the bubble within 25 ms initiated a strong condensation water hammer. The maximum amplitude of the pressure load on the pool wall was approximately 300 kPa. The loads caused by the high compression waves lasted only about 0.4 ms. The loadings caused by larger bubbles or more rapid collapse could not be calculated with the present method. (au)

  16. Understanding the Flow Physics of Shock Boundary-Layer Interactions Using CFD and Numerical Analyses

    Science.gov (United States)

    Friedlander, David J.

    2013-01-01

    Computational fluid dynamic (CFD) analyses of the University of Michigan (UM) Shock/Boundary-Layer Interaction (SBLI) experiments were performed as an extension of the CFD SBLI Workshop held at the 48th AIAA Aerospace Sciences Meeting in 2010. In particular, the UM Mach 2.75 Glass Tunnel with a semi-spanning 7.75deg wedge was analyzed in attempts to explore key physics pertinent to SBLI's, including thermodynamic and viscous boundary conditions as well as turbulence modeling. Most of the analyses were 3D CFD simulations using the OVERFLOW flow solver, with additional quasi-1D simulations performed with an in house MATLAB code interfacing with the NIST REFPROP code to explore perfect verses non-ideal air. A fundamental exploration pertaining to the effects of particle image velocimetry (PIV) on post-processing data is also shown. Results from the CFD simulations showed an improvement in agreement with experimental data with key contributions including adding a laminar zone upstream of the wedge and the necessity of mimicking PIV particle lag for comparisons. Results from the quasi-1D simulation showed that there was little difference between perfect and non-ideal air for the configuration presented.

  17. Responsible Climate Change Adaptation : Exploring, analysing and evaluating public and private responsibilities for urban adaptation to climate change

    NARCIS (Netherlands)

    Mees, Heleen

    2014-01-01

    Cities are vulnerable to climate change. To deal with climate change, city governments and private actors such as businesses and citizens need to adapt to its effects, such as sea level rise, storm surges, intense rainfall and heatwaves. However, adaptation planning and action is often hampered when

  18. NUMERICAL ANALYSES FOR TREATING DIFFUSION IN SINGLE-, TWO-, AND THREE-PHASE BINARY ALLOY SYSTEMS

    Science.gov (United States)

    Tenney, D. R.

    1994-01-01

    This package consists of a series of three computer programs for treating one-dimensional transient diffusion problems in single and multiple phase binary alloy systems. An accurate understanding of the diffusion process is important in the development and production of binary alloys. Previous solutions of the diffusion equations were highly restricted in their scope and application. The finite-difference solutions developed for this package are applicable for planar, cylindrical, and spherical geometries with any diffusion-zone size and any continuous variation of the diffusion coefficient with concentration. Special techniques were included to account for differences in modal volumes, initiation and growth of an intermediate phase, disappearance of a phase, and the presence of an initial composition profile in the specimen. In each analysis, an effort was made to achieve good accuracy while minimizing computation time. The solutions to the diffusion equations for single-, two-, and threephase binary alloy systems are numerically calculated by the three programs NAD1, NAD2, and NAD3. NAD1 treats the diffusion between pure metals which belong to a single-phase system. Diffusion in this system is described by a one-dimensional Fick's second law and will result in a continuous composition variation. For computational purposes, Fick's second law is expressed as an explicit second-order finite difference equation. Finite difference calculations are made by choosing the grid spacing small enough to give convergent solutions of acceptable accuracy. NAD2 treats diffusion between pure metals which form a two-phase system. Diffusion in the twophase system is described by two partial differential equations (a Fick's second law for each phase) and an interface-flux-balance equation which describes the location of the interface. Actual interface motion is obtained by a mass conservation procedure. To account for changes in the thicknesses of the two phases as diffusion

  19. Numerical and experimental analyses of the radiant heat flux produced by quartz heating systems

    Science.gov (United States)

    Turner, Travis L.; Ash, Robert L.

    1994-01-01

    A method is developed for predicting the radiant heat flux distribution produced by tungsten filament, tubular fused-quartz envelope heating systems with reflectors. The method is an application of Monte Carlo simulation, which takes the form of a random walk or ray tracing scheme. The method is applied to four systems of increasing complexity, including a single lamp without a reflector, a single lamp with a Hat reflector, a single lamp with a parabolic reflector, and up to six lamps in a six-lamp contoured-reflector heating unit. The application of the Monte Carlo method to the simulation of the thermal radiation generated by these systems is discussed. The procedures for numerical implementation are also presented. Experiments were conducted to study these quartz heating systems and to acquire measurements of the corresponding empirical heat flux distributions for correlation with analysis. The experiments were conducted such that several complicating factors could be isolated and studied sequentially. Comparisons of the experimental results with analysis are presented and discussed. Good agreement between the experimental and simulated results was obtained in all cases. This study shows that this method can be used to analyze very complicated quartz heating systems and can account for factors such as spectral properties, specular reflection from curved surfaces, source enhancement due to reflectors and/or adjacent sources, and interaction with a participating medium in a straightforward manner.

  20. Numerical analyses of caisson breakwaters on soft foundations under wave cyclic loading

    Science.gov (United States)

    Wang, Yuan-zhan; Yan, Zhen; Wang, Yu-chi

    2016-03-01

    A caisson breakwater is built on soft foundations after replacing the upper soft layer with sand. This paper presents a dynamic finite element method to investigate the strength degradation and associated pore pressure development of the intercalated soft layer under wave cyclic loading. By combining the undrained shear strength with the empirical formula of overconsolidation clay produced by unloading and the development model of pore pressure, the dynamic degradation law that describes the undrained shear strength as a function of cycle number and stress level is derived. Based on the proposed dynamic degradation law and M-C yield criterion, a dynamic finite element method is numerically implemented to predict changes in undrained shear strength of the intercalated soft layer by using the general-purpose FEM software ABAQUS, and the accuracy of the method is verified. The effects of cycle number and amplitude of the wave force on the degradation of the undrained shear strength of the intercalated soft layer and the associated excess pore pressure response are investigated by analyzing an overall distribution and three typical sections underneath the breakwater. By comparing the undrained shear strength distributions obtained by the static method and the quasi-static method with the undrained shear strength distributions obtained by the dynamic finite element method in the three typical sections, the superiority of the dynamic finite element method in predicting changes in undrained shear strength is demonstrated.

  1. Numerical Analyses of Caisson Breakwaters on Soft Foundations Under Wave Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    王元战; 焉振; 王禹迟

    2016-01-01

    A caisson breakwater is built on soft foundations after replacing the upper soft layer with sand. This paper presents a dynamic finite element method to investigate the strength degradation and associated pore pressure development of the intercalated soft layer under wave cyclic loading. By combining the undrained shear strength with the empirical formula of overconsolidation clay produced by unloading and the development model of pore pressure, the dynamic degradation law that describes the undrained shear strength as a function of cycle number and stress level is derived. Based on the proposed dynamic degradation law and M-C yield criterion, a dynamic finite element method is numerically implemented to predict changes in undrained shear strength of the intercalated soft layer by using the general-purpose FEM software ABAQUS, and the accuracy of the method is verified. The effects of cycle number and amplitude of the wave force on the degradation of the undrained shear strength of the intercalated soft layer and the associated excess pore pressure response are investigated by analyzing an overall distribution and three typical sections underneath the breakwater. By comparing the undrained shear strength distributions obtained by the static method and the quasi-static method with the undrained shear strength distributions obtained by the dynamic finite element method in the three typical sections, the superiority of the dynamic finite element method in predicting changes in undrained shear strength is demonstrated.

  2. An anisotropic numerical model for thermal hydraulic analyses: application to liquid metal flow in fuel assemblies

    Science.gov (United States)

    Vitillo, F.; Vitale Di Maio, D.; Galati, C.; Caruso, G.

    2015-11-01

    A CFD analysis has been carried out to study the thermal-hydraulic behavior of liquid metal coolant in a fuel assembly of triangular lattice. In order to obtain fast and accurate results, the isotropic two-equation RANS approach is often used in nuclear engineering applications. A different approach is provided by Non-Linear Eddy Viscosity Models (NLEVM), which try to take into account anisotropic effects by a nonlinear formulation of the Reynolds stress tensor. This approach is very promising, as it results in a very good numerical behavior and in a potentially better fluid flow description than classical isotropic models. An Anisotropic Shear Stress Transport (ASST) model, implemented into a commercial software, has been applied in previous studies, showing very trustful results for a large variety of flows and applications. In the paper, the ASST model has been used to perform an analysis of the fluid flow inside the fuel assembly of the ALFRED lead cooled fast reactor. Then, a comparison between the results of wall-resolved conjugated heat transfer computations and the results of a decoupled analysis using a suitable thermal wall-function previously implemented into the solver has been performed and presented.

  3. NUMERICAL ANALYSES OF DESIGN AND ASSEMBLY FOR MAIN COMPONENTS OF BESIII

    Institute of Scientific and Technical Information of China (English)

    ZENG Pan; LEI Liping; ZHAO Ruihai; LI Ying; CHEN Yuanbo; TANG Xiao

    2007-01-01

    The design and manufacture of the main drift chamber(MDC) and the electro-magnetic calorimeter are most important issues in Beijing electron-positron collider upgraded projects. The whole mass of electro-magnetic calorimeter (EMC) in BESIII is 40t, thus high stiffness, strength and dynamical properties are required for the design of entire structural of electro-magnetic calorimeter. Based on numerical technique, the strength and the dynamical properties of EMC are analyzed, which provide theoretical reference for the design of entire structural of EMC. The MDC is composed of the elements with 28680 pre-stressed high-sensitive wires and during the assembly the wires are stringed layer by layer. The stretching forces of the wires vary continuously and couple with each other in the whole process. The modeling technique with high precision (especially "element birth and death") is carefully used to study the stress state during the process of assembly. So the variations of the stretching force of the wire are investigated, and several design schemes are evaluated and optimized. The research results have been adopted in the Beijing electron-positron collider's new project directly.

  4. Numerical analyses on optical limiting performances of chloroindium phthalocyanines with different substituent positions

    Science.gov (United States)

    Yu-Jin, Zhang; Xing-Zhe, Li; Ji-Cai, Liu; Chuan-Kui, Wang

    2016-01-01

    Optical limiting properties of two soluble chloroindium phthalocyanines with α- and β-alkoxyl substituents in nanosecond laser field have been studied by solving numerically the coupled singlet-triplet rate equation together with the paraxial wave field equation under the Crank-Nicholson scheme. Both transverse and longitudinal effects of the laser field on photophysical properties of the compounds are considered. Effective transfer time between the ground state and the lowest triplet state is defined in reformulated rate equations to characterize dynamics of singlet-triplet state population transfer. It is found that both phthalocyanines exhibit good nonlinear optical absorption abilities, while the compound with α-substituent shows enhanced optical limiting performance. Our ab-initio calculations reveal that the phthalocyanine with α-substituent has more obvious electron delocalization and lower frontier orbital transfer energies, which are responsible for its preferable photophysical properties. Project supported by the National Basic Research Program of China (Grant No. 2011CB808100), the National Natural Science Foundation of China (Grant Nos. 11204078 and 11574082), and the Fundamental Research Funds for the Central Universities of China (Grant No. 2015MS54).

  5. Theoretical and numerical analyses of a slit-masked chicane for modulated bunch generation

    Science.gov (United States)

    Zhu, X.; Broemmelsiek, D. R.; Shin, Y.-M.

    2015-10-01

    Density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The beam modulation is studied with a masked chicane by the analytic model and simulations with the beam parameters of the Fermilab Accelerator Science and Technology (FAST) facility. With the chicane design parameters (bending angle of 18o, bending radius of 0.95 m and R56 ~ -0.19 m) and a nominal beam of 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 μ m and aperture width 300 μ m induces a modulation of bunch-to-bunch spacing ~ 100 μ m to the bunch with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell (PIC) simulations, including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in beam modulation with bunch-to-bunch distance around 100 μ m and a corresponding modulation frequency of 3 THz. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by tracking code Elegant. The simulation analysis indicates that the sliced beam by the slit-mask with 3 ~ 6% correlated energy spread has modulation lengths about 187 μ m (0.25 nC), 270 μ m (1 nC) and 325 μ m (3.2 nC). The theoretical and numerical data proved the capability of the designed masked chicane in producing modulated bunch train with micro-bunch length around 100 fs.

  6. Adapting CALIPSO Climate Measurements for Near Real Time Analyses and Forecasting

    Science.gov (United States)

    Vaughan, Mark A.; Trepte, Charles R.; Winker, David M.; Avery, Melody A.; Campbell, James; Hoff, Ray; Young, Stuart; Getzewich, Brian J.; Tackett, Jason L.; Kar, Jayanta

    2011-01-01

    The Cloud-Aerosol Lidar and Infrared Pathfinder satellite Observations (CALIPSO) mission was originally conceived and designed as a climate measurements mission, with considerable latency between data acquisition and the release of the level 1 and level 2 data products. However, the unique nature of the CALIPSO lidar backscatter profiles quickly led to the qualitative use of CALIPSO?s near real time (i.e., ? expedited?) lidar data imagery in several different forecasting applications. To enable quantitative use of their near real time analyses, the CALIPSO project recently expanded their expedited data catalog to include all of the standard level 1 and level 2 lidar data products. Also included is a new cloud cleared level 1.5 profile product developed for use by operational forecast centers for verification of aerosol predictions. This paper describes the architecture and content of the CALIPSO expedited data products. The fidelity and accuracy of the expedited products are assessed via comparisons to the standard CALIPSO data products.

  7. A record of Holocene climate change from lake geochemical analyses in southeastern Arabia

    Science.gov (United States)

    Parker, Adrian G.; Goudie, Andrew S.; Stokes, Stephen; White, Kevin; Hodson, Martin J.; Manning, Michelle; Kennet, Derek

    2006-11-01

    Lacustrine sediments from southeastern Arabia reveal variations in lake level corresponding to changes in the strength and duration of Indian Ocean Monsoon (IOM) summer rainfall and winter cyclonic rainfall. The late glacial/Holocene transition of the region was characterised by the development of mega-linear dunes. These dunes became stabilised and vegetated during the early Holocene and interdunal lakes formed in response to the incursion of the IOM at approximately 8500 cal yr BP with the development of C3 dominated savanna grasslands. The IOM weakened ca. 6000 cal yr BP with the onset of regional aridity, aeolian sedimentation and dune reactivation and accretion. Despite this reduction in precipitation, the lake was maintained by winter dominated rainfall. There was a shift to drier adapted C4 grasslands across the dune field. Lake sediment geochemical analyses record precipitation minima at 8200, 5000 and 4200 cal yr BP that coincide with Bond events in the North Atlantic. A number of these events correspond with changes in cultural periods, suggesting that climate was a key mechanism affecting human occupation and exploitation of this region.

  8. Responsible Climate Change Adaptation : Exploring, analysing and evaluating public and private responsibilities for urban adaptation to climate change

    OpenAIRE

    Mees, Heleen

    2014-01-01

    Cities are vulnerable to climate change. To deal with climate change, city governments and private actors such as businesses and citizens need to adapt to its effects, such as sea level rise, storm surges, intense rainfall and heatwaves. However, adaptation planning and action is often hampered when the relevant public and private actors have only vague and ambiguous responsibilities. Some exploration on the issue of public and private responsibilities has been undertaken in the literature, b...

  9. An improved lake model for climate simulations: Model structure, evaluation, and sensitivity analyses in CESM1

    Directory of Open Access Journals (Sweden)

    Zachary Subin

    2012-02-01

    Full Text Available Lakes can influence regional climate, yet most general circulation models have, at best, simple and largely untested representations of lakes. We developed the Lake, Ice, Snow, and Sediment Simulator(LISSS for inclusion in the land-surface component (CLM4 of an earth system model (CESM1. The existing CLM4 lake modelperformed poorly at all sites tested; for temperate lakes, summer surface water temperature predictions were 10–25uC lower than observations. CLM4-LISSS modifies the existing model by including (1 a treatment of snow; (2 freezing, melting, and ice physics; (3 a sediment thermal submodel; (4 spatially variable prescribed lakedepth; (5 improved parameterizations of lake surface properties; (6 increased mixing under ice and in deep lakes; and (7 correction of previous errors. We evaluated the lake model predictions of water temperature and surface fluxes at three small temperate and boreal lakes where extensive observational data was available. We alsoevaluated the predicted water temperature and/or ice and snow thicknesses for ten other lakes where less comprehensive forcing observations were available. CLM4-LISSS performed very well compared to observations for shallow to medium-depth small lakes. For large, deep lakes, the under-prediction of mixing was improved by increasing the lake eddy diffusivity by a factor of 10, consistent with previouspublished analyses. Surface temperature and surface flux predictions were improved when the aerodynamic roughness lengths were calculated as a function of friction velocity, rather than using a constant value of 1 mm or greater. We evaluated the sensitivity of surface energy fluxes to modeled lake processes and parameters. Largechanges in monthly-averaged surface fluxes (up to 30 W m22 were found when excluding snow insulation or phase change physics and when varying the opacity, depth, albedo of melting lake ice, and mixing strength across ranges commonly found in real lakes. Typical

  10. Numerical Simulation on Climate Effects of Freezing-Thawing Processes Using CCM3

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A parameterization of soil freezing-thawing physics for use in the land-surface model of the National Center for Atmospheric Research(NCAR) Community Climate Model(CCM3) is developed and evaluated.The new parameterization scheme has improved the representation of physical processes in the existing land surface model.Numerical simulations using CCM3 with improved land-surface processes and with the original land-surface processes are compared against the NCEP reanalysis.It is found that the CCM3 version using the improved land surface model shows significant improvements in simulating precipitation in China during the summer season,the general circulation over East Asia,and wind fields over the Tibet Plateau.For the summer season,the improved model was able to better simulate the Indian summer monsoon components,including the mean northerly wind in the upper troposphere and mean southerly wind in the lower troposphere.

  11. Introduction and systematic assessment for IAP numerical annual climate prediction system

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong; LIN Zhaohui; ZENG Qingcun

    2003-01-01

    The IAP numerical annual climate prediction system has been presented in this paper. In order to evaluate this annual prediction system, annual ensemble hindcast experiments over a 21-year period from 1980 to 2000 have been done. Systematic assessment shows that this annual prediction system has higher predictability for summer climate in tropic than in extra-tropic area, and higher predictabilities over ocean than over land for the fields of precipitation, sea level pressure and surface air temperature; for 500 hPa geopotential height field, the predictability assuming a zonal distribution decreases from tropic to middle-high latitudes, and in China it is the highest among those of all fields. Correlation analysis shows that the prediction ability of IAP annual prediction system to summer temperature is higher than that to precipitation, and the prediction skill can be remarkably improved by the correction system. Furthermore, the comparison between annual and extraseasonal hindcasts indicates that precipitation hindcasted extraseasonally is better than that done annually, and the major discrepancy exists in middle-high latitudes.

  12. Building world narratives for climate change impact, adaptation and vulnerability analyses

    OpenAIRE

    Hallegatte, Stéphane; Valentin, Przyluski; Vogt-Schilb, Adrien

    2011-01-01

    International audience The impacts of climate change on human systems depend not only on the level of emissions but also on how inherently vulnerable these systems are to the changing climate. The large uncertainties over future development and structure of societies and economies mean that the assessment of climate change efects is complex. One way to deal with this complexity is by using scenario analysis that takes account of these socio-economic diferences. The challenge is to identify...

  13. Application of Microneedle Arrays for Enhancement of Transdermal Permeation of Insulin: In Vitro Experiments, Scaling Analyses and Numerical Simulations.

    Science.gov (United States)

    Leeladurga, V; Teja, U Chandra; Sultana, S K Ashraf; Sudeep, K; Anusha, V Sai Sri; Han, Tao; Nalluri, Buchi N; Das, Diganta B

    2016-08-01

    The aim of this investigation is to study the effect of donor concentration and microneedle (MN) length on permeation of insulin and further evaluating the data using scaling analyses and numerical simulations. Histological evaluation of skin sections was carried to evaluate the skin disruption and depth of penetration by MNs. Scaling analyses were done using dimensionless parameters like concentration of drug (C t/C s), thickness (h/L) and surface area of the skin (S a/L (2)). Simulation studies were carried out using MATLAB and COMSOL software to simulate the insulin permeation using histological sections of MN-treated skin and experimental parameters like passive diffusion coefficient. A 1.6-fold increase in transdermal flux and 1.9-fold decrease in lag time values were observed with 1.5 mm MN when compared with passive studies. Good correlation (R (2) > 0.99) was observed between different parameters using scaling analyses. Also, the in vitro and simulated permeations profiles were found to be similar (f 2 ≥ 50). Insulin permeation significantly increased with increase in donor concentration and MN length (p < 0.05). The developed scaling correlations and numerical simulations were found to be accurate and would help researchers to predict the permeation of insulin with new dimensions of MN in optimizing insulin delivery. Overall, it can be inferred that the application of MNs can significantly enhance insulin permeation and may be an efficient alternative for injectable insulin therapy in humans. PMID:26729523

  14. Numerical investigation of climate factors impact on carbon cycle in the East Asian terrestrial ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Mabuchi, K. [Meteorological Research Institute, Tsukuba (Japan); Takahashi, K. [Japan Meteorological Agency, Tokyo (Japan); Nasahara, K.N. [Univ. of Tsukuba (Japan). Inst. of Agricultural and Forest Engineering

    2009-07-01

    The present state of environmental problems due to global warming resulting from increases of greenhouse gases has reached new levels. The international treaty known as the United Nations Framework Convention on Climate Change (UNFCCC) was adopted in 1992 to begin to consider what can be done to reduce global warming. The Kyoto Protocol, adopted in 1997 at the third Conference of the Parties to the UNFCCC (COP 3), proposed a worldwide reduction of greenhouse gas emission. Under these conditions, it became necessary to monitor the increases of greenhouse gases, especially carbon dioxide, and to conduct research to further understand the mechanisms of interactions between environmental changes and the carbon balance. Estimations of the carbon dioxide budget are of great importance in taking the proper steps to deal with increased concentrations due to anthropogenic emissions, and in predictions of future concentration levels. The main components of the carbon dioxide budget are anthropogenic emissions, atmospheric concentration, the exchange between the atmosphere and ocean, and the exchange between the atmosphere and terrestrial ecosystems. Among these components, the role of the terrestrial ecosystem is still uncertain, due to the heterogeneity of that system. Using a regional climate model that includes a terrestrial biosphere model, numerical simulations were performed to clarify the mechanism of the carbon cycle between the terrestrial ecosystem and the atmosphere and to investigate the climate factors impact on the carbon cycle in the East Asian terrestrial ecosystem. Model verifications were performed with regard to the principal elements: precipitation and vegetation phenology. The variations of the atmospheric carbon dioxide concentration simulated by the model were validated using the data at six in situ observatories. After the confirmations of the model performance, regional features of the impact of climate factors on the gross primary production (GPP

  15. Combining analytical frameworks to assess livelihood vulnerability to climate change and analyse adaptation options☆

    Science.gov (United States)

    Reed, M.S.; Podesta, G.; Fazey, I.; Geeson, N.; Hessel, R.; Hubacek, K.; Letson, D.; Nainggolan, D.; Prell, C.; Rickenbach, M.G.; Ritsema, C.; Schwilch, G.; Stringer, L.C.; Thomas, A.D.

    2013-01-01

    Experts working on behalf of international development organisations need better tools to assist land managers in developing countries maintain their livelihoods, as climate change puts pressure on the ecosystem services that they depend upon. However, current understanding of livelihood vulnerability to climate change is based on a fractured and disparate set of theories and methods. This review therefore combines theoretical insights from sustainable livelihoods analysis with other analytical frameworks (including the ecosystem services framework, diffusion theory, social learning, adaptive management and transitions management) to assess the vulnerability of rural livelihoods to climate change. This integrated analytical framework helps diagnose vulnerability to climate change, whilst identifying and comparing adaptation options that could reduce vulnerability, following four broad steps: i) determine likely level of exposure to climate change, and how climate change might interact with existing stresses and other future drivers of change; ii) determine the sensitivity of stocks of capital assets and flows of ecosystem services to climate change; iii) identify factors influencing decisions to develop and/or adopt different adaptation strategies, based on innovation or the use/substitution of existing assets; and iv) identify and evaluate potential trade-offs between adaptation options. The paper concludes by identifying interdisciplinary research needs for assessing the vulnerability of livelihoods to climate change. PMID:25844020

  16. Meta-analyses of the determinants and outcomes of belief in climate change

    Science.gov (United States)

    Hornsey, Matthew J.; Harris, Emily A.; Bain, Paul G.; Fielding, Kelly S.

    2016-06-01

    Recent growth in the number of studies examining belief in climate change is a positive development, but presents an ironic challenge in that it can be difficult for academics, practitioners and policy makers to keep pace. As a response to this challenge, we report on a meta-analysis of the correlates of belief in climate change. Twenty-seven variables were examined by synthesizing 25 polls and 171 academic studies across 56 nations. Two broad conclusions emerged. First, many intuitively appealing variables (such as education, sex, subjective knowledge, and experience of extreme weather events) were overshadowed in predictive power by values, ideologies, worldviews and political orientation. Second, climate change beliefs have only a small to moderate effect on the extent to which people are willing to act in climate-friendly ways. Implications for converting sceptics to the climate change cause--and for converting believers’ intentions into action--are discussed.

  17. A new numerical framework for simulating the control of weather and climate on the evolution of soil-mantled hillslopes

    Science.gov (United States)

    Bovy, Benoît; Braun, Jean; Demoulin, Alain

    2016-06-01

    We present a new numerical framework for simulating short to long-term hillslope evolution. This modeling framework, to which we have given the name CLICHE (CLImate Control on Hillslope Evolution), aims to better capture the control of climate on soil dynamics. It allows the use of realistic forcing that involves, through a specific time discretization scheme, the variability of both the temperature and precipitation at time scales ranging from the daily rainfall events to the climatic oscillations of the Quaternary, also including seasonal variability. Two simple models of soil temperature and soil water balance permit the link between the climatic inputs and derived quantities that take part in the computation of the soil flux, such as the surface water discharge and the depth of the non-frozen soil layer. Using this framework together with a multi-process parameterization of soil transport, we apply an original method to calculate hillslope effective diffusivity as a function of climate. This allows us to demonstrate the ability of the model to simulate observed rates of hillslope erosion under different climates (cold and temperate) with a single set of parameter values. Numerical experiments furthermore suggest a potential high peak of sediment transport on hillslopes during the glacial-interglacial transitions of the Quaternary. We finally discuss the need to improve the parameterization of the soil production and transport processes in order to explicitly account for other key controlling factors that are also climate-sensitive, such as biological activity.

  18. A numerical model of continental topographic evolution integrating thin sheet tectonics, river transport, and climate

    Science.gov (United States)

    Garcia-Castellanos, D.; Jimenez-Munt, I.

    2013-12-01

    How much does the erosion and sedimentation at the crust's surface influence on the patterns and distribution of tectonic deformation? This question has been mostly addressed from a numerical modelling perspective, at scales ranging from local to orogenic. Here we present a model that aims at constraining this phenomenon at the continental scale. With this purpose, we couple a thin-sheet viscous model of continental deformation with a stream-power surface transport model. The model also incorporates flexural isostatic compensation that permits the formation of large sedimentary foreland basins and a precipitation model that reproduces basic climatic effects such as continentality and orographic rainfall and rain shadow. We quantify the feedbacks between these 4 processes in a synthetic scenario inspired by the India-Asia collision. The model reproduces first-order characteristics of the growth of the Tibetan Plateau as a result of the Indian indentation. A large intramountain basin (comparable to the Tarim Basin) develops when predefining a hard inherited area in the undeformed foreland (Asia). The amount of sediment trapped in it is very sensitive to climatic parameters, particularly to evaporation, because it crucially determines its endorheic/exorheic drainage. We identify some degree of feedback between the deep and the surface processes occurs, leading locally to a <20% increase in deformation rates if orographic precipitation is account for (relative to a reference model with evenly-distributed precipitation). These enhanced thickening of the crust takes place particularly in areas of concentrated precipitation and steep slope, i.e., at the upwind flank of the growing plateau. This effect is particularly enhanced at the corners of the indenter (syntaxes). We hypothesize that this may provide clues for better understanding the mechanisms underlying the intriguing tectonic aneurisms documented in the syntaxes of the Himalayas.

  19. Numerical simulation of the impact of underlying surface changes on Arctic climate

    Institute of Scientific and Technical Information of China (English)

    LIU Xiying; XIA Huasheng

    2014-01-01

    Using a regional atmospheric model for Arctic climate simulation, two groups of numerical experiments were carried out to study the inlfuence of changes in the underlying surface (land surface, sea surface, and sea ice (LS/SS/SI)) from mild ice years to severe ice years on Arctic climate. In each experiment in the same group, the initial values and lateral boundary conditions were identical. The underlying surface conditions were updated every six hours. The model was integrated for 10 a and monthly mean results were saved for analysis. Variations in annual mean surface air temperature were closely correlated with changes in LS/SS/SI, with a maximum change of more than 15 K. The impact of changes in LS/SS/SI on low-level air temperature was also evident, with signiifcant changes seen over the ocean. However, the maximum change was less than 2 K. For air temperature above 700 hPa, the impact of LS/SS/SI changes was not signiifcant. The distribution of annual mean sea level pressure differences was coincident with the distribution of annual mean sea ice concentration. The difference centers were located in the Barents Sea, the Kara Sea, and the East Siberian Sea, with the maximum value exceeding 3 hPa. For geopotential height, some results passed and some failed at-test. For results passing thet-test, the area of signiifcance did not decrease with height. There was a signiifcant difference at high levels, with a value of 27 gpm in the difference center at 200 hPa.

  20. Numerical analyses of the electromagnetic force acting on high-temperature superconducting power cables due to fault current

    International Nuclear Information System (INIS)

    In Japan, the development of the 66 kV class REB2C3O7−x (RE123; RE stands for rare earth) high-temperature superconducting (HTS) power cable was begun in 2008 as a national project. 66 kV class RE123 HTS power cables may be subjected to a fault current of 31.5 kArms for 2 s. Therefore, the electromagnetic and thermal characteristics of HTS power cables have to be determined under fault conditions to ensure stability and feasibility. In this study, numerical analyses were performed using a computer program on the basis of the finite element method and an equivalent circuit model to evaluate the electromagnetic and thermal behaviors of a 66 kV class HTS model cable resulting from the fault current. The electromagnetic forces acting on coated conductors that are assembled in the HTS model cable were also numerically simulated under the fault condition. The result found was that the maximum electromagnetic force acting on the coated conductor in the peeling and compression direction was less than 20 kPa. However, the irreversible Ic degradations caused by the peeling and compression stress were above several MPa in previous studies. Thus, the results of this study indicate a low probability of Ic degradation of the 66 kV class HTS power cable being caused by the electromagnetic force due to the fault current. (paper)

  1. Combining analytiacal frameworks to assess livelihood vulnerability to climate change and analyse adaptiation option

    NARCIS (Netherlands)

    Reed, M.S.; Podesta, G.; Fazey, I.; Geeson, N.; Hessel, R.; Hubacek, K.; Letson, D.; Nainggolan, D.; Prell, C.; Rickenbach, M.G.; Ritsema, C.J.; Schwilch, G.; Springer, L.C.; Thomas, A.D.

    2013-01-01

    Experts working on behalf of international development organisations need better tools to assist land managers in developing countries maintain their livelihoods, as climate change puts pressure on the ecosystem services that they depend upon. However, current understanding of livelihood vulnerabili

  2. Analysing the Scalability of Climate Codes Using New Features of Scalasca

    OpenAIRE

    Harlacher, M.; Calotoiu, A.; Dennis, J; de Wolf, F

    2016-01-01

    This paper shows how recently developed features of the performance analysis tool Scalasca helped gain important insights into the performance behaviour of state-of-the-art climate codes in the CESM (Community Earth System Model) ensemble. Particular emphasis is given to the load balance of the sea-ice model and the scaling behaviour of the atmospheric model. The presented work is a result of the project Enabling Climate Simulation at Extreme Scale, which has been funded through the G8 Resear...

  3. Predictability of Regional Climate: A Bayesian Approach to Analysing a WRF Model Ensemble

    Science.gov (United States)

    Bruyere, C. L.; Mesquita, M. D. S.; Paimazumder, D.

    2013-12-01

    This study investigates aspects of climate predictability with a focus on climatic variables and different characteristics of extremes over nine North American climatic regions and two selected Atlantic sectors. An ensemble of state-of-the-art Weather Research and Forecasting Model (WRF) simulations is used for the analysis. The ensemble is comprised of a combination of various physics schemes, initial conditions, domain sizes, boundary conditions and breeding techniques. The main objectives of this research are: 1) to increase our understanding of the ability of WRF to capture regional climate information - both at the individual and collective ensemble members, 2) to investigate the role of different members and their synergy in reproducing regional climate 3) to estimate the associated uncertainty. In this study, we propose a Bayesian framework to study the predictability of extremes and associated uncertainties in order to provide a wealth of knowledge about WRF reliability and provide further clarity and understanding of the sensitivities and optimal combinations. The choice of the Bayesian model, as opposed to standard methods, is made because: a) this method has a mean square error that is less than standard statistics, which makes it a more robust method; b) it allows for the use of small sample sizes, which are typical in high-resolution modeling; c) it provides a probabilistic view of uncertainty, which is useful when making decisions concerning ensemble members.

  4. A NUMERICAL SIMULATION OF THE EFFECT ON CHINESE REGIONAL CLIMATE DUE TO SEASONAL VARIATION OF LAND SURFACE PARAMETERS (PART I)

    Institute of Scientific and Technical Information of China (English)

    孙健; 李维亮; 周秀骥

    2001-01-01

    Sensitivity experiment is an important method to study the effect on regional climate due to seasonal variation of land surface parameters. Using China Regional Climate Model (CRCM)nested in CCM1, we first simulate Chinese regional climate, then two numerical sensitivity experiments on the effect of vegetation and roughness length are made. The results show that:(1) If the vegetation is replaced with the monthly data of 1997, precipitation and land-surface temperature are both changed clearly, precipitation decreases and land surface temperature increases, but there is no regional correspondence between these changes. And the results are much better than the results when climate average vegetation was used in the CRCM. (2) If the roughness length is replaced with the monthly data of 1997, there is significant change on land surface temperature, and there is very good regional correspondence between these changes. But the effect on precipitation is very small.

  5. A new hierarchical Bayesian approach to analyse environmental and climatic influences on debris flow occurrence

    Science.gov (United States)

    Jomelli, Vincent; Pavlova, Irina; Eckert, Nicolas; Grancher, Delphine; Brunstein, Daniel

    2015-12-01

    How can debris flow occurrences be modelled at regional scale and take both environmental and climatic conditions into account? And, of the two, which has the most influence on debris flow activity? In this paper, we try to answer these questions with an innovative Bayesian hierarchical probabilistic model that simultaneously accounts for how debris flows respond to environmental and climatic variables. In it, full decomposition of space and time effects in occurrence probabilities is assumed, revealing an environmental and a climatic trend shared by all years/catchments, respectively, clearly distinguished from residual "random" effects. The resulting regional and annual occurrence probabilities evaluated as functions of the covariates make it possible to weight the respective contribution of the different terms and, more generally, to check the model performances at different spatio-temporal scales. After suitable validation, the model can be used to make predictions at undocumented sites and could be used in further studies for predictions under future climate conditions. Also, the Bayesian paradigm easily copes with missing data, thus making it possible to account for events that may have been missed during surveys. As a case study, we extract 124 debris flow event triggered between 1970 and 2005 in 27 catchments located in the French Alps from the French national natural hazard survey and model their variability of occurrence considering environmental and climatic predictors at the same time. We document the environmental characteristics of each debris flow catchment (morphometry, lithology, land cover, and the presence of permafrost). We also compute 15 climate variables including mean temperature and precipitation between May and October and the number of rainy days with daily cumulative rainfall greater than 10/15/20/25/30/40 mm day- 1. Application of our model shows that the combination of environmental and climatic predictors explained 77% of the overall

  6. Framework for multi-scale integrated impact analyses of climate change mitigation options

    NARCIS (Netherlands)

    Perez-Soba, M.; Parr, T.; Roupioz, L.F.S.; Winograd, M.; Peña-Claros, M.; Varela Ortega, C.; Ascarrunz, N.; Balvanera, P.; Bholanath, P.; Equihua, M.; Guerreiro, L.; Jones, L.; Maass, M.; Thonicke, K.

    2013-01-01

    Tropical forest ecosystems are hotspots for biodiversity and represent one of the largest terrestrial carbon stocks, making their role in climate change mitigation (CCM) programmes increasingly important (e.g. REDD+). In Latin America these ecosystems suffer from high land use pressures that have re

  7. Impact of climate change on the distribution of Aedes albopictus (Diptera: Culicidae) in northern Japan: retrospective analyses.

    Science.gov (United States)

    Mogi, Motoyoshi; Tuno, Nobuko

    2014-05-01

    The impact of climate change on the distribution of Aedes albopictus (Skuse) was analyzed in northern Japan, where chronological distribution records are incomplete. We analyzed local climate data using linear regression of the thermal suitability index (TSI) for the mosquito and mean annual temperature as functions of time. In northern Japan, thermal conditions since the early 20th century have become increasingly suitable for Ae. albopictus, more as a result of decreasing coldness in the overwintering season than increasing warmth in the reproductive season. Based on recent discovery records of Ae. albopictus in the northern border range, we determined thermal criteria for estimating when its persistent establishment became thermally possible. Retrospective analyses indicated that those criteria were reached in most coastal lowlands of northern Honshu before the accelerated temperature increase after the mid-1980s and the first records of this species after 1990; at some sites, temperature criteria were reached during or before the early 20th century. Expansion of the thermally suitable range after 1990 was supported only for inland areas and the northernmost Pacific coast. The estimated expansion rate was approximately 26 km per decade. Our analyses also demonstrated the importance of local climate heterogeneity (apart from north-south or altitudinal temperature gradients) in determining the expansion pattern. PMID:24897849

  8. Impact of climate change on the distribution of Aedes albopictus (Diptera: Culicidae) in northern Japan: retrospective analyses.

    Science.gov (United States)

    Mogi, Motoyoshi; Tuno, Nobuko

    2014-05-01

    The impact of climate change on the distribution of Aedes albopictus (Skuse) was analyzed in northern Japan, where chronological distribution records are incomplete. We analyzed local climate data using linear regression of the thermal suitability index (TSI) for the mosquito and mean annual temperature as functions of time. In northern Japan, thermal conditions since the early 20th century have become increasingly suitable for Ae. albopictus, more as a result of decreasing coldness in the overwintering season than increasing warmth in the reproductive season. Based on recent discovery records of Ae. albopictus in the northern border range, we determined thermal criteria for estimating when its persistent establishment became thermally possible. Retrospective analyses indicated that those criteria were reached in most coastal lowlands of northern Honshu before the accelerated temperature increase after the mid-1980s and the first records of this species after 1990; at some sites, temperature criteria were reached during or before the early 20th century. Expansion of the thermally suitable range after 1990 was supported only for inland areas and the northernmost Pacific coast. The estimated expansion rate was approximately 26 km per decade. Our analyses also demonstrated the importance of local climate heterogeneity (apart from north-south or altitudinal temperature gradients) in determining the expansion pattern.

  9. Examining the response of larch needle carbohydrates to climate using compound-specific δ13C and concentration analyses

    Science.gov (United States)

    Rinne, Katja T.; Saurer, Matthias; Kirdyanov, Alexander V.; Bryukhanova, Marina V.; Prokushkin, Anatoly S.; Churakova Sidorova, Olga V.; Siegwolf, Rolf T. W.

    2016-04-01

    Little is known about the dynamics of concentrations and carbon isotope ratios of individual carbohydrates in leaves in response to climatic and physiological factors. Improved knowledge of the isotopic ratio in sugars will enhance our understanding of the tree ring isotope ratio and will help to decipher environmental conditions in retrospect more reliably. Carbohydrate samples from larch (Larix gmelinii) needles of two sites in the continuous permafrost zone of Siberia with differing growth conditions were analysed with the Compound-Specific Isotope Analysis (CSIA). We compared concentrations and carbon isotope values (δ13C) of sucrose, fructose, glucose and pinitol combined with phenological data. The results for the variability of the needle carbohydrates show high dynamics with distinct seasonal characteristics between and within the studied years with a clear link to the climatic conditions, particularly vapour pressure deficit. Compound-specific differences in δ13C values as a response to climate were detected. The δ13C of pinitol, which contributes up to 50% of total soluble carbohydrates, was almost invariant during the whole growing season. Our study provides the first in-depth characterization of compound-specific needle carbohydrate isotope variability, identifies involved mechanisms and shows the potential of such results for linking tree physiological responses to different climatic conditions.

  10. Analyses of climate and extreme indices in Central and Eastern Europe within the CECILIA project

    Science.gov (United States)

    Hirschi, M.; Boberg, F.; Christensen, O. B.; Seneviratne, S. I.; Stepanek, P.; Wp4 Members, Cecilia

    2009-04-01

    The EU-project CECILIA (Central and Eastern Europe Climate Change Impact and VulnerabiLIty Assessment) aims at delivering a climate change impacts and vulnerability assessment in targeted areas of Central and Eastern Europe. This region appears particularly vulnerable with regard to future changes in extremes (Christensen and Christensen 2003, Schär et al. 2004), likely due to regional specificities such as highly varying topography and continentality, and due to changes in soil moisture content (Seneviratne et al. 2006). In the project, emphasis is given to applications of regional climate modeling studies at a resolution of 10 km for local impact studies in key sectors of the region. The project includes the analysis of extreme weather events in present day and future climate in the target region. For this purpose, an extensive list of precipitation and temperature indices was defined. Observational data used for the indices calculation comes from the European Climate Assessment & Dataset project (ECA&D, Klein Tank et al. 2002), from the ENSEMBLES gridded observations (E-Obs, Haylock et al. 2008), and from station data of the local partners in Central and Eastern Europe. Moreover, the same indices were calculated consistently for a selection of pre-existing RCM datasets (PRUDENCE, ENSEMBLES), and for the CECILIA driving models. Later on, the 10 km high-resolution climate simulations from CECILIA will be included in the analysis. Here we focus on the analysis of a selection of temperature indices, and on the validation of the model-derived indices with the observations. Generally, the spatial agreement between the models and the observations is very good for mean, maximum and minimum temperature (both in terms of the spatial variability and the spatial correlation). The spread between the models is larger for the daily temperature range, with most models showing larger spatial variability compared to the observations. When it comes to heat and cold wave indices

  11. Energetic and exergetic analyses of carbon dioxide transcritical refrigeration systems for hot climates

    Directory of Open Access Journals (Sweden)

    Fazelpour Farivar

    2015-01-01

    Full Text Available In the last two decades many scientific papers and reports have been published in the field of the application of the carbon dioxide as a refrigerant for refrigeration systems and heat pumps. Special attention has been paid to the transcritical cycle. However, almost no papers discussed such cycles for hot climates, i.e., when the temperature of the environment is higher than 40ºС during a long period of time. This paper deals with the energetic and exergetic evaluation of a CO2 refrigeration system operating in a transcritical cycle under hot climatic conditions. The performance and exergy efficiency of the CO2 refrigeration system depend on the operation conditions. The effect of varying these conditions is also investigated as well as the limitations associated with these conditions.

  12. Late Holocene climatic changes in Tierra del Fuego based on multiproxy analyses of peat deposits

    OpenAIRE

    Mauquoy, D.; Blaauw, Maarten; van Geel, B; Borromei, A.; M. Quattrocchio; Chambers, F.M.; Possnert, G.

    2004-01-01

    A ca. 1400-yr record from a raised bog in Isla Grande, Tierra del Fuego, Argentina, registers climate fluctuations, including a Medieval Warm Period, although evidence for the 'Little Ice Age' is less clear. Changes in temperature and/or precipitation were inferred from plant macrofossils, pollen, fungal spores, testate amebae, and peat humification. The chronology was established using a C-14 wiggle-matching technique that provides improved age control for at least part of the record compare...

  13. Energetic and exergetic analyses of carbon dioxide transcritical refrigeration systems for hot climates

    OpenAIRE

    Fazelpour Farivar

    2015-01-01

    In the last two decades many scientific papers and reports have been published in the field of the application of the carbon dioxide as a refrigerant for refrigeration systems and heat pumps. Special attention has been paid to the transcritical cycle. However, almost no papers discussed such cycles for hot climates, i.e., when the temperature of the environment is higher than 40ºС during a long period of time. This paper deals with the energetic and exerget...

  14. The climate change law of the federal government. Analyses and proposals to its further development; Das Klimaschutzrecht des Bundes. Analyse und Vorschlaege zu seiner Weiterentwicklung

    Energy Technology Data Exchange (ETDEWEB)

    Sina, Stephan; Garstetter, Christiane; Bausch, Camilla; Goerlach, Benjamin; Neubauer, Alexander [Ecologic gGmbH Institut fuer Internationale und Europaeische Umweltpolitik, Berlin (Germany); Rodi, Michael [Greifswald Univ. (Germany). Lehrstuhl fuer oeffentliches Recht, Finanz- und Steuerrecht

    2011-09-15

    The present report provides an analysis of the current German federal climate change law. Due to the crosssectoral character of this law, the study comprises regulations from different sectors and areas of law such as emissions trading, the energy sector and agriculture. Based on this analysis, proposals for the advancement of the German federal law of climate change are developed in five particular areas: a potential outline for a general climate protection act serving as the central legal act for climate change law, further considerations on the structure of climate change law, development proposals related to energy grids, federal requirements for municipal climate protection as well as agricultural land use. (orig.)

  15. The effect of climate forcing on numerical simulations of the Cordilleran ice sheet at the Last Glacial Maximum

    OpenAIRE

    Seguinot, J.; C. Khroulev; I. Rogozhina; A. P. Stroeven; Q. Zhang

    2013-01-01

    We present an ensemble of numerical simulations of the Cordilleran ice sheet during the Last Glacial Maximum performed with the Parallel Ice Sheet Model (PISM), applying temperature offsets to the present-day climatologies from five different datasets. Monthly mean surface air temperature and precipitation from WorldClim, the NCEP/NCAR reanalysis, the ERA-Interim reanalysis, the Climate Forecast System Reanalysis and the North American Regional Reanalysis ar...

  16. The effect of climate forcing on numerical simulations of the Cordilleran ice sheet at the Last Glacial Maximum

    OpenAIRE

    Seguinot, J.; C. Khroulev; I. Rogozhina; A. P. Stroeven; Q. Zhang

    2014-01-01

    We present an ensemble of numerical simulations of the Cordilleran ice sheet during the Last Glacial Maximum performed with the Parallel Ice Sheet Model (PISM), applying temperature offsets to the present-day climatologies from five different data sets. Monthly mean surface air temperature and precipitation from WorldClim, the NCEP/NCAR reanalysis, the ERA-Interim reanalysis, the Climate Forecast System Reanalysis and the North American Regional Reanalysis are used to compute surface mass bal...

  17. ICLEA - The Virtual Institute of Integrated Climate and Landscape Evolution Analyses

    Science.gov (United States)

    Schwab, Markus J.; Brauer, Achim; Błaszkiewicz, Mirosław; Blume, Theresa; Itzerott, Sibylle; Raab, Thomas; Wilmking, Martin; Iclea Team

    2016-04-01

    In the Virtual Institute ICLEA we view on past changes as natural experiments as a guidebook for better anticipation of future changes and their impacts. Since the natural evolution became increasingly superimposed by human impacts since the Neolithic we include an in-depth discussion of impacts of climate and environment change on societies and vice versa. The partner focusing their research capacities and expertise in ICLEA and offers young researchers an interdisciplinary and structured education and promote their early independence through coaching and mentoring. Training, Research and Analytical workshops between research partners of ICLEA are an important measure to qualify young researchers. Understanding causes and effects of present-day climate change on landscapes and the human habitat faces two main challenges, (I) too short time series of instrumental observation that do not cover the full range of variability since mechanisms of climate change and landscape evolution work on different time scales, which often not susceptible to human perception, and, (II) distinct regional differences due to the location with respect to oceanic/continental climatic influences, the geological underground, and the history and intensity of anthropogenic land-use. Both challenges are central for the ICLEA research strategy and demand a high degree of interdisciplinary. In particular, the need to link observations and measurements of ongoing changes with information from the past taken from natural archives requires joint work of scientists with very different time perspectives. On the one hand, scientists that work at geological time scales of thousands and more years and, on the other hand, those observing and investigating recent processes at short time scales. The long-term mission of the Virtual Institute is to provide a substantiated data basis for sustained environmental maintenance based on a profound process understanding at all relevant time scales. Aim is to

  18. Recent Regional Climate State and Change - Derived through Downscaling Homogeneous Large-scale Components of Re-analyses

    Science.gov (United States)

    Von Storch, H.; Klehmet, K.; Geyer, B.; Li, D.; Schubert-Frisius, M.; Tim, N.; Zorita, E.

    2015-12-01

    Global re-analyses suffer from inhomogeneities, as they process data from networks under development. However, the large-scale component of such re-analyses is mostly homogeneous; additional observational data add in most cases to a better description of regional details and less so on large-scale states. Therefore, the concept of downscaling may be applied to homogeneously complementing the large-scale state of the re-analyses with regional detail - wherever the condition of homogeneity of the large-scales is fulfilled. Technically this can be done by using a regional climate model, or a global climate model, which is constrained on the large scale by spectral nudging. This approach has been developed and tested for the region of Europe, and a skillful representation of regional risks - in particular marine risks - was identified. While the data density in Europe is considerably better than in most other regions of the world, even here insufficient spatial and temporal coverage is limiting risk assessments. Therefore, downscaled data-sets are frequently used by off-shore industries. We have run this system also in regions with reduced or absent data coverage, such as the Lena catchment in Siberia, in the Yellow Sea/Bo Hai region in East Asia, in Namibia and the adjacent Atlantic Ocean. Also a global (large scale constrained) simulation has been. It turns out that spatially detailed reconstruction of the state and change of climate in the three to six decades is doable for any region of the world.The different data sets are archived and may freely by used for scientific purposes. Of course, before application, a careful analysis of the quality for the intended application is needed, as sometimes unexpected changes in the quality of the description of large-scale driving states prevail.

  19. The analyses of extreme climate events over China based on CMIP5 historical and future simulations

    Science.gov (United States)

    Yang, S.; Dong, W.; Feng, J.; Chou, J.

    2013-12-01

    The extreme climate events have a serious influence on human society. Based on observations and 12 simulations from Coupled Model Intercomparison Project Phase 5 (CMIP5), Climatic extremes and their changes over china in history and future scenarios of three Representative Concentration Pathways (RCPs) are analyzed. Because of the background of global warming, in observations, the frost days (FD) and low-temperature threshold days (TN10P) have decreasing trend, and summer days (SU), high-temperature threshold days (TX90P), the heavy precipitation days (R20) and contribution of heavy precipitation days (P95T) show an increasing trend. Most coupled models can basically simulate main characteristics of most extreme indexes. The models reproduce the mean FD and TX90P value best and can give basic trends of the FD, TN10P, SU and TX90P. High correlation coefficients between simulated results and observation are found in FD, SU and P95T. For FD and SU index, most of the models have good ability to capture the spatial differences between the mean state of the 1986-2005 and 1961-1980 periods, but for other indexes, most of models' simulation ability for spatial disparity are not so satisfactory and have to be promoted. Under the high emission scenario of RCP8.5, the century-scale linear changes of Multi-Model Ensembles (MME) for FD, SU, TN10P, TX90P, R20 and P95T are -46.9, 46.0, -27.1, 175.4, 2.9 days and 9.9%, respectively. Due to the complexities of physical process parameterizations and the limitation of forcing data, a large uncertainty still exists in the simulations of climatic extremes. Fig.1 Observed and modeled multi-year average for each index (Dotted line: observation) Table1. Extreme index definition

  20. Southern African continental climate since the late Pleistocene: Insights from biomarker analyses of Kalahari salt pan sediments

    Science.gov (United States)

    Belz, Lukas; Schüller, Irka; Wehrmann, Achim; Wilkes, Heinz

    2016-04-01

    The climate system of sub-tropical southern Africa is mainly controlled by large scale atmospheric and marine circulation processes and, therefore, very sensitive to global climate change. This underlines the importance of paleoenvironmental reconstructions in order to estimate regional implications of current global changes. However, the majority of studies on southern African paleoclimate are based on the investigation of marine sedimentary archives and past climate development especially in continental areas is still poorly understood. This emphasizes the necessity of continental proxy-data from this area. Proxy datasets from local geoarchives especially of the southwestern Kalahari region are still scarce. A main problem is the absence of conventional continental climatic archives, due to the lack of lacustrine systems. In this study we are exploring the utility of sediments from western Kalahari salt pans, i.e. local depressions which are flooded temporarily during rainfall events. An age model based on 14C dating of total organic carbon (TOC) shows evidence that sedimentation predominates over erosional processes with respect to pan formation. Besides the analyses of basic geochemical bulk parameters including TOC, δ13CTOC, total inorganic carbon, δ13CTIC, δ18OTIC, total nitrogen and δ15N, our paleo-climatic approach focuses on reconstruction of local vegetation assemblages to identify changes in the ecosystem. This is pursued using plant biomarkers, particularly leaf wax n-alkanes and n-alcohols and their stable carbon and hydrogen isotopic signatures. Results show prominent shifts in n-alkane and n-alkanol distributions and compound specific carbon isotope values, pointing to changes to a more grass dominated environment during Heinrich Stadial 1 (18.5-14.6 ka BP), while hydrogen isotope values suggest wetter phases during Holocene and LGM. This high variability indicates the local vulnerability to global change.

  1. A technology framework to analyse the Climate Change impact on biodiversity species distribution

    Science.gov (United States)

    Nativi, S.; Khalsa, S. J.; Geller, G. N.; O'Tuama, E.; Thomas, D.; Mazzetti, P.; Santoro, M.

    2009-04-01

    Several biodiversity application scenarios require modeling the impact of climate change on species distribution. For this purpose, heterogeneous data resources and modeling services are required to interoperate. An information technology and service framework to study the Climate Change impact on biodiversity species distribution is presented. This framework allows the development of relevant biodiversity application scenarios. These draw on data and information exchange from a series of systems interconnected through SOA (Service Oriented Architecture) applying established international standards as well as Community interoperability arrangements. The overall system architecture consists of six main logical components: - Biodiversity Data Provider: a component which is able to provide biodiversity data. - Climatological Data Provider: a component which is able to provide climatological data. - Catalog: a component which is able to perform queries on the available biodiversity and climatological datasets. - Model Provider: a component which is able to run ENM (Ecological Niche Models) on the selected biodiversity and climatological datasets. - Use Scenario Controller: a component which acts as a workflow controller implementing the business process of a typical biodiversity scenario. It is controlled by the user through the GUI. - Graphical User Interface (GUI): The component for user interaction. It controls the workflow manager to perform the required operations for implementing the biodiversity basic scenario. These components play the three typical roles of a SOA where Consumers discover Providers through a Registry. In our framework Data and Model providers are the Service Providers; the GUI-Controller pair acts as a Consumer and the Catalog plays the role of the Registry. Where necessary it also acts as a Broker between Consumer and Providers. This fourth component is necessary for heterogeneous and federated systems. The framework was conceived and

  2. Analyses of Observed and Anticipated Changes in Extreme Climate Events in the Northwest Himalaya

    Directory of Open Access Journals (Sweden)

    Dharmaveer Singh

    2016-02-01

    Full Text Available In this study, past (1970-2005 as well as future long term (2011-2099 trends in various extreme events of temperature and precipitation have been investigated over selected hydro-meteorological stations in the Sutlej river basin. The ensembles of two Coupled Model Intercomparison Project (CMIP3 models: third generation Canadian Coupled Global Climate Model and Hadley Centre Coupled Model have been used for simulation of future daily time series of temperature (maximum and minimum and precipitation under A2 emission scenario. Large scale atmospheric variables of both models and National Centre for Environmental Prediction/National Centre for Atmospheric Research reanalysis data sets have been downscaled using statistical downscaling technique at individual stations. A total number of 25 extreme indices of temperature (14 and precipitation (11 as specified by the Expert Team of the World Meteorological Organization and Climate Variability and Predictability are derived for the past and future periods. Trends in extreme indices are detected over time using the modified Mann-Kendall test method. The stations which have shown either decrease or no change in hot extreme events (i.e., maximum TMax, warm days, warm nights, maximum TMin, tropical nights, summer days and warm spell duration indicators for 1970–2005 and increase in cold extreme events (cool days, cool nights, frost days and cold spell duration indicators are predicted to increase and decrease respectively in the future. In addition, an increase in frequency and intensity of extreme precipitation events is also predicted.

  3. Late Quaternary climate and environmental changes in a permafrost section near Igarka, Northern Siberia based on leaf wax analyses

    Science.gov (United States)

    Schaefer, Imke; Schweri, Lea; Zech, Jana; Tananaev, Nikita; Zech, Roland

    2016-04-01

    Leaf wax biomarkers, such as long chain n-alkanes and n-alkanoic acids, and their carbon isotopic composition are a promising tool for reconstructing past climate and environmental changes and gain more and more attention in paleoresearch. Here we present the results of leaf wax analyses from a permafrost outcrop at the left banks of the Yenisei River near the city of Igarka, Northern Russia. Fluvio-glacial sediments are exposed in the lower part of the outcrop and probably date back to ~60 ka. The upper part consist of aeolian sediments deposited since, overprinted by various pedogenetic processes. First results indicate a continuous contribution of deciduous trees to the vegetation during the last glacial. Compound specific deuterium and radiocarbon analyses are in progress in order to investigate changes in paleoclimate and to establish a robust chronology.

  4. Permafrost response to climate change: Linking field observation with numerical simulation

    Science.gov (United States)

    Hayashi, M.; Rivière, A.; Quinton, W. L.; McKenzie, J. M.; Voss, C. I.

    2013-12-01

    The Scotty Creek basin (152 km2) is located in the Northwest Territories, Canada, within the peat-covered discontinuous permafrost zone with a high density of wetlands. The extensive peat layer (up to 3-4 m thick) is underlain by generally clay-rich glacial sediments. The landcover consists of peat plateaus underlain by permafrost, permafrost-free channel fens, and connected and isolated permafrost-free ombrotrophic flat bogs, occurring as a complex mosaic of patches. The runoff from peat plateaus drains into isolated bogs and a network of connected bogs and fens. During the course of field studies since 1999, stark changes have been observed on the permafrost plateaus, including a deepening of active layer, soil settlement and depression formation, and changes in the lateral and vertical extent of the unsaturated zone. In general, the area of permafrost plateaus is decreasing, and the areas of fens and bog areas are increasing. These changes affect water flow and induce changes in heat transport, which in turn affect the aforementioned changes in permafrost plateaus (i.e. feedback processes). The goal of this study is to understand the feedbacks and their effects on permafrost degradation by used of the field observations and numerical simulations. We use a modified version of the three-dimensional SUTRA model that can simulate groundwater flow and heat transport, including freeze-thaw processes. Numerical simulation of heat transport accounts for the effects of latent heat associated with freezing and thawing, and variable heat capacity, thermal conductivity, and permeability as a function of ice content. The model is used to simulate the plateau-fen-bog complex, where intensive field studies have generated a large amount of data. The SUTRA model does not simulate complex surface processes such as radiative and turbulent heat exchange, snow accumulation and melt, and canopy effects. We use an energy and water transfer model, Northern Ecosystem Soil Temperature

  5. Numerical Simulation of Long-Term Climate Change in East Asia

    Institute of Scientific and Technical Information of China (English)

    TANG Jianping; SU Bingkai; ZHAO Ming; ZHAO Deming

    2006-01-01

    A 10-yr regional climate simulation was performed using the fifth-generation PSU/NCAR Mesoscale Model Version 3 (MM5V3) driven by large-scale NCEP/NCAR reanalyses. Simulations of winter and summer mean regional climate features were examined against observations. The results showed that the model could well simulate the 10-yr winter and summer mean circulation, temperature, and moisture transport at middle and low levels. The simulated winter and summer mean sea level pressure agreed with the NCAR/NCEP reanalysis data. The model could well simulate the distribution and intensity of winter mean precipitation rates as well as the distribution of summer mean precipitation rates, but it overestimated the summer mean precipitation over North China. The model's ability to simulate the regional climate change in winter was superior to that in summer. In addition, the model could simulate the inter-annual variation of seasonal precipitation and surface air temperature. Geopotential heights and temperature at middle and high levels between simulations and observations exhibited high anomaly correlation coefficients. The model also showed large variability to simulate the regional climate change associated with the El Nino events. The MM5V3 well simulated the anomalies of summer mean precipitation in 1992 and 1995, while it demonstrated much less ability to simulate that in 1998. Generally speaking, the MM5V3 is capable of simulating the regional climate change, and could be used for long-term regional climate simulation.

  6. Climate change in the Iberian Upwelling System: a numerical study using GCM downscaling

    Science.gov (United States)

    Cordeiro Pires, Ana; Nolasco, Rita; Rocha, Alfredo; Ramos, Alexandre M.; Dubert, Jesus

    2016-07-01

    The present work aims at evaluating the impacts of a climate change scenario on the hydrography and dynamics of the Iberian Upwelling System. Using regional ocean model configurations, the study domain is forced with three different sets of surface fields: a climatological dataset to provide the control run; a dataset obtained from averaging several global climate models (GCM) that integrate the Intergovernmental Panel for Climate Change (IPCC) models used in climate scenarios, for the same period as the climatological dataset; and this same dataset but for a future period, retrieved from the IPCC A2 climate scenario. After ascertaining that the ocean run forced with the GCM dataset for the present compared reasonably well with the climatologically forced run, the results for the future run (relative to the respective present run) show a general temperature increase (from +0.5 to +3 °C) and salinity decrease (from -0.1 to -0.3), particularly in the upper 100-200 m, although these differences depend strongly on season and distance to the coast. There is also strengthening of the SST cross-shore gradient associated to upwelling, which causes narrowing and shallowing of the upwelling jet. This effect is contrary to the meridional wind stress intensification that is also observed, which would tend to strengthen the upwelling jet.

  7. A NUMERICAL SIMULATION OF THE EFFECT ON CHINESE REGIONAL CLIMATE DUE TO SEASONAL VARIATION OF LAND SURFACE PARAMETERS (PART II)

    Institute of Scientific and Technical Information of China (English)

    孙健; 李维亮; 周秀骥

    2001-01-01

    The effect on climate due to seasonal variation of vegetation and roughness length was simulated in Part I of this essay. In Part II, the individual effect of albedo and the joint effect of all those factors (vegetation, roughness length and albedo) were calculated by numerical sensitivity experiments. The results showed that: (1) There is no significant effect on precipitation if the albedo of 4 seasons is used to replace the CRCM's climate average data, but the effect on land surface temperature can be seen clearly. And the effect also can be seen in adjacent regions. (2) If all these three factors are used to replace the CRCM's climate average data at the same time, the effect on precipitation is significant, the most variation value is 300 mm. And the effect on temperature is similar to what we can see if only one of these factors in CRCM is replaced by monthly or seasonal data. (3) Seasonal variation of land surface parameters has important effect not only on regional climate, but also on global environment.

  8. Grid-Mapping of Hellas Planitia, Mars - Geostatistical Analyses of Cold-Climate Landforms

    Science.gov (United States)

    Voelker, Martin; Hauber, Ernst; Jaumann, Ralf

    2016-10-01

    Hellas Planitia is one of the largest impact basins on Mars, with a diameter of 2,300 km and located in the southern mid-latitudes. The basin also contains the topographically lowest parts of the planet, making it of special interest for water and ice-related geomorphological activities. We applied a Grid-Mapping method to analyze the geographical distribution of possibly ice-related landforms (e.g., latitude-dependent mantle [LDM] and scalloped terrain) in a visual and statistical manner. Thus, we are able to look for yet unrecognized correlations between the landforms themselves and external parameters such as elevation, slope inclination, slope aspect (azimuth), and thermal inertia.By using this method, the study area is separated into 20,100 grids, each 20×20 km. Mapping is based on CTX images at a scale of 1:30,000 in a GIS environment. Because of the huge size of the study area, only every second grid has been mapped. For 21 different landforms, we attributed one of the five following classes to each grid: "dominant", "present", "possible", "absent", and "no data". The non-mapped grids were interpolated later. Statistical calculations have only considered "dominant" and "present" values for reliable results. In normalized distribution diagrams only bins with more than 30 samples are shown.Despite LDM covers Hellas almost entirely, our map shows an elliptical 800×200 km gap in NE Hellas. We suggest this lack of LDM may be the result of the dominant wind circulation pattern within the basin. According to global climate models, cold south-polar wind currents enter Hellas at a breach in its SW rim and rotate clockwise in Hellas. When they reach the northern parts of the Hellas floor around 30°S they warm up, and begin to move south again, subliming or preventing the evolution of LDM in the NE portions of Hellas because of the higher air temperature. In contrast to LDM, scalloped terrain occurs on higher inclined slopes between 6° to 9°. As they are

  9. Numerical modeling of shoreline undulations part 2: Varying wave climate and comparison with observations

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg; Fredsøe, Jørgen

    2013-01-01

    waves with a directional spreading. In this paper, these findings are extended to firstly include the effect of a varying wave climate on the shoreline morphology and secondly, to tune the model to two naturally occurring shorelines. It is found that the effect of a variable wave climate is to slow down...... the development of the morphology and in some cases to inhibit the formation of shore-parallel spits at the crest of the undulations. On one of the natural shorelines, the west coast of Namibia, the shore is exposed to very obliquely waves from one main direction. Here, the shoreline model is able to...

  10. Numerical simulations of a full-scale polymer electrolyte fuel cell with analysing systematic performance in an automotive application

    International Nuclear Information System (INIS)

    Highlights: • A 3-D full-scale fuel cell performance is numerically simulated. • Generated and consumed power in the system is affected by operating condition. • Systematic analysis predicts the net power of conceptual PEFC stack. - Abstract: In fuel cell powered electric vehicles, the net power efficiency is a critical factor in terms of fuel economy and commercialization. Although the fuel cell stack produces enough power to drive the vehicles, the transferred power to the power train could be significantly reduced due to the power consumption to operate the system components of air blower and cooling module. Thus the systematic analysis on the operating condition of the fuel cell stack is essential to predict the net power generation. In this paper numerical simulation is conducted to characterize the fuel cell performance under various operating conditions. Three dimensional and full-scale fuel cell of the active area of 355 cm2 is numerically modelled with 47.3 million grids to capture the complexities of the fluid dynamics, heat transfer and electrochemical reactions. The proposed numerical model requires large computational time and cost, however, it can be powerful to reasonably predict the fuel cell system performance at the early stage of conceptual design without requiring prototypes. Based on the model, it has been shown that the net power is reduced down to 90% of the gross power due to the power consumption of air blower and cooling module

  11. NUMERICAL SIMULATION OF INFLUENCE OF INDIAN OCEAN SSTA ON WEATHER AND CLIMATE IN ASIAN MONSOON REGION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Sea surface temperature anomaly (SSTA) exerts great influence on the generation of global weather and climate. Much progress has been made with respect to SSTA in the Pacific Ocean region in contrast to the Indian Ocean. The IAP9L model, which is developed at the Institute of Atmospheric Physics of the Chinese Academy of Science, is used to simulate the influence of the Indian Ocean SSTA on the general circulation and weather/climate anomalies in the monsoon region of Asia. It is found that the warm (cool) SSTA in the equatorial low latitudes of the Indian Ocean triggers winter (summer) teleconnection patterns in middle and higher latitudes of the Northern Hemisphere that are similar to PNA or EAP. They play a very important role in the anomaly of circulation or weather and climate in the middle and lower latitudes of the Asian summer monsoon region. With the warm (cool) SSTA forcing in the Indian Ocean, the Asian summer monsoon sets up at a late (early) date and withdraws at a early (late) date, lasting for a short (long) duration at a weak (strong) intensity. The Indian Ocean SSTA is shown to be an indicator for precipitation variation in China.

  12. Climate Sensitivity of Franz-Josef Glacier, New Zealand, as revealed by numerical modelling

    NARCIS (Netherlands)

    Oerlemans, J.

    1997-01-01

    The sensitivity of Franz Josef Glacier is studied with a numerical ice-flow model. The model calculates ice mass flux along a central flow line and deals with the three-dimensional geometry in a parameterized way. Forcing is provided through a mass balance model that generates specific balance from

  13. Testing the Ability of Numerical Model to Simulate Climate and Its Change With 4D-EOF Analysis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The four-dimensional empirical orthogonal function (4D-EOF), which in reality is a simple combination of three-dimensional EOF (3D-EOF) and extended EOF (EEOF), is put forward in this paper to test the ability of numerical model to simulate climate and its change. The 4D-EOF analysis is able to reveal not only the horizontal characteristic pattern of analyzed variable, and its corresponding annual and inter-annual variations, but also the vertical structural characteristics. The method suggested is then used to analyze the monthly mean 100-, 500-, 700-, and 1000-hPa geopotential height fields (4941 grids and grid spacing 60 km) and their anomaly fields in 1989-1998 simulated by the MM5V3 from the RMIP (Regional Climate Model Inter-comparison Project for East Asia)-Ⅱ, as well as their counterparts (used as the observed fields)from the NCEP/NCAR re-analysis dataset in the same period. The ability of MM5V3 in simulating East Asian climate and its change is tested by comparing the 4D-EOF analysis results of the simulated and observed datasets. The comparative analyzed results show that the horizontal pattern of the first eigenvector of the observed monthly mean geopotential height fields and its vertical equivalent barotropic feature were well simulated; the simulations of the first two eigenvectors of the observed monthly mean geopotential height anomaly fields were also successful for their horizontal abnormal distributions and significant equivalent barotropic features in the vertical were well reproduced; and furthermore, the observed characteristics,such as the variation with height, the annual and inter-annual variations of the monthly mean geopotential height/anomaly fields were also well reflected in the simulation. Therefore, the 4D-EOF is able to comprehensively test numerical model's ability of simulating the climate and its change, and the simulation ability of MM5V3 for the climate and its change in East Asia in the 1990s was satisfactory.

  14. Numerical analyses on optimizing a heat pipe thermal management system for lithium-ion batteries during fast charging

    International Nuclear Information System (INIS)

    Thermal management is crucial for the operation of electric vehicles because lithium ion batteries are vulnerable to excessive heat generation during fast charging or other severe scenarios. In this work, an optimized heat pipe thermal management system (HPTMS) is proposed for fast charging lithium ion battery cell/pack. A numerical model is developed and comprehensively validated with experimental results. This model is then employed to investigate the thermal performance of the HPTMS under steady state and transient conditions. It is found that a cylinder vortex generator placed in front of the heat pipe condensers in the coolant stream improves the temperature uniformity. The uses of cooper heat spreaders and cooling fins greatly improve the performance of the thermal management system. Experiments and transient simulations of heat pipe thermal management system integrated with batteries prove that the improved HPTMS is capable for thermal management of batteries during fast charging. The air-cooled HPTMS is infeasible for thermal management of batteries during fast charging at the pack level due to the limitation of low specific heat capacity. - Highlights: • We develop a numerical model for optimizing a heat pipe thermal management system for fast charging batteries. • The numerical model is comprehensively validated with experimental data. • A cylinder vortex generator is placed at the inlet of the cooling stream to improve the temperature uniformity. • We validate the effectiveness of the optimized system with integration of prismatic batteries

  15. Impact of the closure of Indonesian seaway on climate: A numerical modeling study

    Institute of Scientific and Technical Information of China (English)

    YU Yongqiang; ZHOU Zuyi; ZHANG Xuehong

    2003-01-01

    Using a global OGCM and its relevant coupled ocean-atmosphere GCM with the contemporary, 6 MaBP and 14 MaBP oceanic topography, respectively, a series of numerical experiments are implemented in order to investigate the effect of the north shift of Australian continent on the tropical oceanic circulation, especially the formation of the western Pacific warm pool. The numerical experiments of the individual OGCM forced by the modern atmospheric circulation indicate that the closure of Indonesian passage results in warming in the tropical Pacific Ocean and cooling in the tropical Indian Ocean; furthermore, it also results in change in source of the Indonesian Through Flow (ITF) water, e.g. ITF mainly originates from the south Pacific at 14 MaBP, but it mainly originates from the north Pacific now. The coupled model shows similar results as the individual OGCM qualitatively.

  16. 3-D Numerical Modeling of Heat Transport Phenomena in Soil under Climatic Conditions of Southern Thailand

    Directory of Open Access Journals (Sweden)

    Jompob WAEWSAK

    2014-12-01

    Full Text Available This paper presents a 3-D numerical modeling of heat transport phenomena in soil due to a change of sensible and latent heat, under the ambient conditions of southern Thailand. The vertical soil temperature profile within 3 m was predicted based on energy balance and 3 modes of heat transfer mechanisms, i.e., conduction, convection, and radiation. Mathematical models for estimation of solar radiation intensity, ambient and sky temperatures, relative humidity, and surface wind velocity were used as model inputs. 3-D numerical implicit finite difference schemes, i.e., forward time, and forward, center, and backward spaces were used for discretizing the set of governing, initial, and boundary condition equations. The set of pseudo-linear equations were then solved using the single step Gauss-Seidel iteration method. Computer code was developed by using MATLAB computer software. The soil physical effects; density, thermal conductivity, emissivity, absorptivity, and latent heat on amplitude of soil temperature variation were investigated. Numerical results were validated in comparison to the experimental results. It was found that 3-D numerical modeling could predict the soil temperature to almost the same degree as results that were obtained by experimentation, especially at a depth of 1 m. The root mean square error at ground surface and at depths of 0.5, 1, 1.5, 2, 2.5 and 3 m were 0.169, 0.153, 0.097, 0.116, 0.120, 0.115, and 0.098, respectively. Furthermore, it was found that variation of soil temperature occurred within 0.75 m only.

  17. Numerical model predictions of autogenic fluvial terraces and comparison to climate change expectations

    Science.gov (United States)

    Limaye, Ajay B. S.; Lamb, Michael P.

    2016-03-01

    Terraces eroded into sediment (alluvial) and bedrock (strath) preserve an important history of river activity. River terraces are thought to form when a river switches from a period of slow vertical incision and valley widening to fast vertical incision and terrace abandonment. Consequently, terraces are often interpreted to reflect changing external drivers including tectonics, sea level, and climate. In contrast, the intrinsic unsteadiness of lateral migration in rivers may generate terraces even under constant rates of vertical incision without external forcing. To explore this mechanism, we simulate landscape evolution by a vertically incising, meandering river and isolate the age and geometry of autogenic river terraces. Modeled autogenic terraces form for a wide range of lateral and vertical incision rates and are often paired and longitudinally extensive for intermediate ratios of vertical-to-lateral erosion rate. Autogenic terraces have a characteristic reoccurrence time that scales with the time for relief generation. There is a preservation bias against older terraces due to reworking of previously visited parts of the valley. Evolving, spatial differences in bank strength between bedrock and sediment reduce terrace formation frequency and length, favor pairing, and can explain sublinear terrace margins at valley boundaries. Age differences and geometries for modeled autogenic terraces are consistent, in cases, with natural terraces and overlap with metrics commonly attributed to terrace formation due to climate change. We suggest a new phase space of terrace properties that may allow differentiation of autogenic terraces from terraces formed by external drivers.

  18. Theoretical analyses and numerical experiments of variational assimilation for one-dimensional ocean temperature model with techniques in inverse problems

    Institute of Scientific and Technical Information of China (English)

    HUANG Sixun; HAN Wei; WU Rongsheng

    2004-01-01

    In the present work, the data assimilation problem in meteorology and physical oceanography is re-examined using the variational optimal control approaches in combination with regularization techniques in inverse problem. Here the estimations of the initial condition,boundary condition and model parameters are performed simultaneously in the framework of variational data assimilation. To overcome the difficulty of ill-posedness, especially for the model parameters distributed in space and time, an additional term is added into the cost functional as a stabilized functional. Numerical experiments show that even with noisy observations the initial conditions and model parameters are recovered to an acceptable degree of accuracy.

  19. Experimental and numerical analyses of pure copper during ECFE process as a novel severe plastic deformation method

    Directory of Open Access Journals (Sweden)

    M. Ebrahimi

    2014-02-01

    Full Text Available In this paper, a new severe plastic deformation method called equal channel forward extrusion (ECFE process has been proposed and investigated by experimental and numerical approaches on the commercial pure copper billets. The experimental results indicated that the magnitudes of yield strength, ultimate tensile strength and Vickers micro-hardness have been markedly improved from 114 MPa, 204 MPa and 68 HV as the annealed condition to 269 MPa, 285 MPa and 126 HV after the fourth pass of ECFE process, respectively. In addition, scanning electron microscopy observation of the samples showed that the average grain size of the as-received state which is about 22 μm has been reduced to 1.4 μm after the final pass. The numerical investigation suggested that although one pass ECFE process fabricates material with the mean effective strain magnitude of about 1, the level of imposed effective plastic strain gradually diminishes from the circumference to the center of the deformed billet.

  20. Numerical Analyses of Bearing Capacity of Deep-Embedded Large-Diameter Cylindrical Structure on Soft Ground Against Lateral Loads

    Institute of Scientific and Technical Information of China (English)

    LUAN Mao-tian; FAN Qing-lai

    2006-01-01

    Presented in this paper is a three-dimensional plastic limit analysis method of bearing capacity of the deeply-embedded large-diameter cylindrical structure in the cross-anisotropic soft ground. The most likely failure mechanism is assumed to be of a composite rupture surface which is composed of an individual wedge in the passive zone or two wedges in both active and passive zones near the mudline, depending on the separation or bonding state at the interface between the cylindrical structure and neighboring soils in the active wedge, and a truncated spherical slip surface at the base of the cylinder when the structure tends to overturn around a point located on the symmetry axis of the structure. The cylindrical structure and soil interaction system under consideration is also numerically analyzed by the finite element method by virtue of the general-purpose FEM software ABAQUS, in which the soil is assumed to obey tie Hill's criterion of yield. Both the failure mechanism assumed and the plastic limit analysis predictions are validated by numerical computations based on FEM. For the K0-consolidated ground of clays typically with anisotropic undrained strength property, it is indicated through a parametric study that limit analysis without consideration of anisotropy of soil overestimates the lateral ultimate bearing capacity of a deeply-embedded cylindrical structure in soft ground in a certain condition.

  1. GIS-Mapping and Statistical Analyses to Identify Climate-Vulnerable Communities and Populations Exposed to Superfund Sites

    Science.gov (United States)

    Climate change-related cumulative health risks are expected to be disproportionately greater for overburdened communities, due to differential proximity and exposures to chemical sources and flood zones. Communities and populations vulnerable to climate change-associated impacts ...

  2. Gliese 581d Habitable with a CO2-rich atmosphere: Results from Numerical Climate Simulations.

    Science.gov (United States)

    Wordsworth, Robin; Forget, F.; Selsis, F.; Madeleine, J. B.; Millour, E.; Eymet, V.

    2010-10-01

    The exoplanet Gl581d (discovered in 2007) is relatively low mass and near to the outer edge of its system's habitable zone, which has led to much speculation on its possible climate. To help understand the possible conditions on this planet, we have developed a new universal 3D global climate model (GCM). It is derived from the LMD GCMs already used to simulate the Earth, Mars and other terrestrial atmospheres in the solar system, and hence has already been validated over a wide range of physical conditions. We have performed a range of simulations to assess whether, given simple combinations of chemically stable gases (CO2, H2O and N2), Gl581d could sustain liquid water on its surface. Compared to a Sun-like star, the red dwarf Gliese 581 allows higher planetary temperatures, because Rayleigh scattering is reduced. Taking into account the scattering greenhouse effect of both CO2 and H2O clouds, we find that several tens of bars of CO2 are sufficient to maintain global mean temperatures above the melting point of water. As Gl581d is probably in a tidally resonant orbit, condensables such as water and CO2 may be trapped on its dark sides or poles. However, we find that even with conservative assumptions, redistribution of heat by the atmosphere is enough to allow stable conditions with surface liquid water. A dense atmosphere of this kind is quite possible for such a large planet, and could be distinguished from other cases using future observations.

  3. Safety of existing installations under dynamic loads: observations on nonlinear response of piping systems - experiments, numerical analyses

    International Nuclear Information System (INIS)

    The nonlinear response of piping systems under base excitation or due to pressure waves caused by simulated breaks and valve closure has been investigated experimentally at the HDR reactor. Structural analysis of ruptured piping and the related design of pipe whips restraints are usually performed on the basis of nonlinear material behavior, with powerful computational techniques being used increasingly. Some aspects of these developments (high-level earthquake tests, high-level pressure wave tests, pipe rupture nonlinear analyses) are summarized with implications for qualification and optimal backfitting of operating nuclear power plants. (Z.S.) 7 refs

  4. Numerical analysis of DNA microarray data of Campylobacter jejuni strains correlated with survival, cytolethal distending toxin and haemolysin analyses

    DEFF Research Database (Denmark)

    On, Stephen L.W.; Dorrell, N.; Petersen, L.;

    2006-01-01

    -genome microarray analysis was used to determine the gene-level complementarity of 12 Danish strains to the pathogenic, genome-sequenced strain NCTC 11168. Cytolethal distending toxin (CDT) and haemolysin activities, and survival characteristics under aerobic conditions at room temperature were also determined....... Among the strains examined, 439 genes were polymorphic. Numerical analysis of these data by use of the squared Euclidean distance coefficient and Ward's clustering method clearly delineated strains into two clusters. CDT and haemolysin activities of cluster 1 strains were not statistically significantly...... flagellar, lipo-oligosaccharide, and membrane transport proteins. Our data indicate a correlation between C. jejuni genomic content, particularly in surface-coding regions, and its capacity for environmental survival, and may help explain why certain serotypes are more commonly reported in human disease....

  5. Study on dynamic response of embedded long span corrugated steel culverts using scaled model shaking table tests and numerical analyses

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A series of scaled-model shaking table tests and its simulation analyses using dynamic finite element method were performed to clarify the dynamic behaviors and the seismic stability of embedded corrugated steel culverts due to strong earthquakes like the 1995 Hyogoken-nanbu earthquake. The dynamic strains of the embedded culvert models and the seismic soil pressure acting on the models due to sinusoidal and random strong motions were investigated. This study verified that the corrugated culvert model was subjected to dynamic horizontal forces (lateral seismic soil pressure) from the surrounding ground,which caused the large bending strains on the structure; and that the structures do not exceed the allowable plastic deformation and do not collapse completely during strong earthquake like Hyogoken-nanbu earthquake. The results obtained are useful for design and construction of embedded long span corrugated steel culverts in seismic regions.

  6. Numerical analyses and experiment investigations of an annular micro gas turbine power system using fuels with low heating values

    Institute of Scientific and Technical Information of China (English)

    YANG ChunHsiang; LEE ChengChia; HSIAO JenHao; CHEN ChiunHsun

    2009-01-01

    This study investigates the effects of using fuels with low heating values on the performance of an annular micro gas turbine(MGT)experimentally and numerically.The MGT used in this study is MW-54,whose original fuel is liquid(Jet al).Its fuel supply system is re-designed to use biogas fuel with low heating value(LHV).The purpose is to reduce the size of a biogas distributed power supply system and to enhance its popularization.This study assesses the practicability of using fuels with LHVs by using various mixing ratios of methane(CH_4)and carbon dioxide(CO_2).Prior to experiments,the corresponding simulations,aided by the commercial code CFD-ACE+,were carried out to investigate the cooling effect in a perforated combustion chamber and combustion behavior in an annular MGT when LHV gas was used.The main purposes are to confirm that there are no hot spots occurring in the liners and the exhaust temperatures of combustor are lower than 700℃ when MGT is operated under different conditions,in experiments,fuel pressure and mass flow rate,turbine rotational speed,generator power output,and temperature distribution were measured to analyze MGT performance.Experimental results indicate that the presented MGT system operates successfully under each tested condition when the minimum heating value of the simulated fuel is approximately 50%of pure methane.The power output is around 170 W at 85000 r/min as 90%CH_4 with 10%CO_2 is used and 70 W at 60000 r/min as 70%CH_4 with 30%CO_2 is used.When a critical limit of 60%CH_4 is used,the power output is extremely low.Furthermore,the best theoretical Brayton cycle efficiency for such MGT is calculated as 23%according to the experimental data while LHV fuel is used.Finally,the numerical results and experiment results reveal that MGT performance can be improved further and the possible solutions for performance improvement are suggested for the future studies.

  7. Numerical analyses and experiment investigations of an annular micro gas turbine power system using fuels with low heating values

    Institute of Scientific and Technical Information of China (English)

    YANG; ChunHsiang; LEE; ChengChia; HSIAO; JenHao; CHEN; ChiunHsun

    2009-01-01

    This study investigates the effects of using fuels with low heating values on the performance of an annular micro gas turbine(MGT)experimentally and numerically.The MGT used in this study is MW-54, whose original fuel is liquid(Jet A1).Its fuel supply system is re-designed to use biogas fuel with low heating value(LHV).The purpose is to reduce the size of a biogas distributed power supply system and to enhance its popularization.This study assesses the practicability of using fuels with LHVs by using various mixing ratios of methane(CH4)and carbon dioxide(CO2).Prior to experiments,the corresponding simulations,aided by the commercial code CFD-ACE+,were carried out to investigate the cooling effect in a perforated combustion chamber and combustion behavior in an annular MGT when LHV gas was used.The main purposes are to confirm that there are no hot spots occurring in the liners and the exhaust temperatures of combustor are lower than 700°C when MGT is operated under different conditions.In experiments,fuel pressure and mass flow rate,turbine rotational speed,generator power output,and temperature distribution were measured to analyze MGT performance.Experimental results indicate that the presented MGT system operates successfully under each tested condition when the minimum heating value of the simulated fuel is approximately 50%of pure methane.The power output is around 170 W at 85000 r/min as 90%CH4 with 10%CO2 is used and 70 W at 60000 r/min as 70%CH4 with 30%CO2 is used.When a critical limit of 60%CH4 is used,the power output is extremely low. Furthermore,the best theoretical Brayton cycle efficiency for such MGT is calculated as 23%according to the experimental data while LHV fuel is used.Finally,the numerical results and experiment results reveal that MGT performance can be improved further and the possible solutions for performance im- provement are suggested for the future studies.

  8. Acoustic Defect-Mode Waveguides Fabricated in Sonic Crystal: Numerical Analyses by Elastic Finite-Difference Time-Domain Method

    Science.gov (United States)

    Miyashita, Toyokatsu

    2006-05-01

    A novel acoustic waveguide composed of a line of single defects in a sonic crystal is shown to have desirable properties for acoustic circuits. The absence of a scatterer, i.e., a single defect or a point defect, in artificial crystals such as photonic crystals and phononic crystals leads to some localized resonant modes around the defect. Single defects in a sonic crystal made of acrylic resin cylinders in air are shown in this paper to have resonant modes or defect modes, which are excited successively to form a mode guided along a line of defects. Both a straight waveguide and a sharp bending waveguide composed of lines of single defects are shown equally to have a good transmission with small reflections at the inlet as well as at the outlet within the full band gap of the sonic crystal. Their advantages over conventional line-defect waveguides are clearly shown by their transmission versus frequency characteristics and also by typical examples of their spatial acoustic field distribution. On the basis of these properties, coupled defect-mode waveguides are investigated, and a high mode-coupling ratio is obtained. Defect-mode waveguides in a sonic crystal are expected to be desirable elements for functional acoustic circuits. The results of the elastic finite difference time domain (FDTD) method used as a tool of numerical calculation are also investigated and precisely compared with the experimental band gaps.

  9. Analyses of Numerical Responses and Main Life Parameters for Determining the Suppression of Amblyseius cucumeris on Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-xuan; LIN Jian-zhen; JI Jie; CHEN Xie; KANG Yu-mei

    2005-01-01

    In this paper, the numeral response and main parameters of experimental population life table were analyzed for determiningthe suppressing ability of Amblyseius cucumeris on Panonychus citri. The result showed that: (1) Under 21-31 ℃ and 1-9 prey densities/leaf fragment condition, the prey consumptions ofA. cucumeris increased with the temperature or prey density; (2) In 1:3 predator-prey ratio treatment, the suppression ofP. citri (Ro=34.0053; T=19.4369; t=3.8204) was rather weak, it was enhanced as the ratio over 5:30, and the populations ofP. citri in these treatments can be fully controlled within 4-5 days; (3) Under 25±1℃, 80-85% RH and 15L: 9D illumination conditions, the net reproductive rate, mean generation duration and the time for population double increase ofP. citri (Ro=34.0053; T=19.4369; t=3.8204) were higher than those ofA. cucumeris (Ro=21.8750; T=16.8943; t=3.7954). While the intrinsic rate of increase and finite rate of increase of the former (rm=0.1814; λ= 1.1989) were lower than those of the latter (rm=0.1826; λ= 1.2004). These results indicated that A. cucumeris is a desirable bio-control agent to suppress P. citri at lower population stage in citrus orchard.

  10. Integrated numerical modeling of a landslide early warning system in a context of adaptation to future climatic pressures

    Science.gov (United States)

    Khabarov, Nikolay; Huggel, Christian; Obersteiner, Michael; Ramírez, Juan Manuel

    2010-05-01

    Mountain regions are typically characterized by rugged terrain which is susceptible to different types of landslides during high-intensity precipitation. Landslides account for billions of dollars of damage and many casualties, and are expected to increase in frequency in the future due to a projected increase of precipitation intensity. Early warning systems (EWS) are thought to be a primary tool for related disaster risk reduction and climate change adaptation to extreme climatic events and hydro-meteorological hazards, including landslides. An EWS for hazards such as landslides consist of different components, including environmental monitoring instruments (e.g. rainfall or flow sensors), physical or empirical process models to support decision-making (warnings, evacuation), data and voice communication, organization and logistics-related procedures, and population response. Considering this broad range, EWS are highly complex systems, and it is therefore difficult to understand the effect of the different components and changing conditions on the overall performance, ultimately being expressed as human lives saved or structural damage reduced. In this contribution we present a further development of our approach to assess a landslide EWS in an integral way, both at the system and component level. We utilize a numerical model using 6 hour rainfall data as basic input. A threshold function based on a rainfall-intensity/duration relation was applied as a decision criterion for evacuation. Damage to infrastructure and human lives was defined as a linear function of landslide magnitude, with the magnitude modelled using a power function of landslide frequency. Correct evacuation was assessed with a ‘true' reference rainfall dataset versus a dataset of artificially reduced quality imitating the observation system component. Performance of the EWS using these rainfall datasets was expressed in monetary terms (i.e. damage related to false and correct evacuation). We

  11. Numerical and Experimental Pore-scale Analyses of Inert and Reactive Multiple Colloidal Particles in Complex Flow Domains

    Science.gov (United States)

    Basagaoglu, H.; Succi, S.; Melchionna, S.; Allwein, S.; Dixon, H.

    2008-12-01

    A fluctuating lattice-Boltzmann model was developed to simulate pore-scale flow and transport of multiple particles in geometrically complex porous and fractured domains. The model is based on the original work of Ladd [J. Fluid Mech., 271, 285, 1994] and the modeling approach based on the virtual intraparticle fluid nodes as proposed by Ding and Aidun [J. Stat. Phys., 112, 685, 2003]. The model has been improved by introducing two-body electrostatic and van der Waals potentials. Moreover, the commonly used bounce-back algorithm to simulate no-slip conditions has been replaced by an immersed boundary condition to simulate softer particle-wall interactions. The simulation results captured the wall and inertial effects on trajectories of a single particle in different Reynolds number flows in smooth-walled channels, consistent with earlier numerical simulation results. Multiple-particle simulations in porous and fractured domains captured trains of particles crossing multiple streamlines in fast-flow paths and lagged particles in slow-flow paths as has been observed in our experiments and reported in the literature. Experimental studies are focused on two-dimensional flow for three microflow cell geometries and use monodispersed particles in dense and dilute concentrations. The average particle sizes are 2, 10 and 30 microns, and the interaction between particle surfaces is controlled by the use of surfactants. Three two- dimensional flow cells with a 50 to 500 micron width have been manufactured to evaluate scale effects. Preliminary results are available for the flow of 2 micron poly(lactic-co-glycolic acid) [PLGA] microspheres dispersed in polyvinyl alcohol solution (PVA) in a 500-micron tube with inline flow obstruction with dilute and concentrated solutions. These results demonstrate particle streamlines and show particle-particle and particle-wall interactions. The experimental findings are compared with simulation results.

  12. SLOPE FAILURE MECHANISMS IN COHESIVE SOILS: INSIGHTS FROM THEORETICAL AND NUMERICAL ANALYSES OF FIELD AND LABORATORY-TRIGGERED EVENTS

    Science.gov (United States)

    Malet, J.; Spickermann, A.; van Asch, T.

    2009-12-01

    A landslide can show a variety of failure modes which depends on the given conditions of the slope such as geometry, material characteristics and presence of discontinuities. Besides the gravity as main loading factor, it is assumed that slope failures are often caused by hydrological processes. The identification and modelling of failure modes and triggering mechanisms are essential requirements in landslide forecasting and in the design of reliable early warning systems. This work is an attempt to get a better understanding of the mode of failure and possible failure mechanisms taking place in cohesive slopes. Theoretical analysis has been carried out on the basis of (1) field observations of two failure events of the clay-rich Super-Sauze mudslide (Southeast France) and (2) small-scale landslides triggered in a flume using clay from Zoelen (Netherlands) and reworked black marls from Super-Sauze. To investigate the failure behaviour numerically a simple analytical model, named 2LM (Landslide Liquefaction Model) (van Asch et al. 2006; van Asch & Malet, in press) is used. The model assumes that liquefaction is related to previous development of slip surfaces, i.e. deformation of the landslide body (sliding blocks, slumps) during motion leading to the generation of excess pore water pressure and thus to fluidization. The model is based on the theory of limiting equilibrium dividing the area above an estimated slip surface into slices of constant width. Immediately after failure, the difference in movement for each slice is calculated assuming a viscous shear band and using the Coulomb-viscous model. The differential movements conduct to differential strains which are transferred to excess pore water pressures. The potential fluidization is then evaluated for each slice in relation to the displacements. Results from an application of this model on the two slump-type failures that occurred in the Super-Sauze mudslide are presented. Then the model is applied to the

  13. Design and analysis of high-numerical-aperture beam shaping systems; Design und Analyse von Strahlformungssystemen hoher numerischer Apertur

    Energy Technology Data Exchange (ETDEWEB)

    Schweitzer, Hagen

    2009-11-24

    The generation of light tailored to measure stands today in the center of many innovative applications. A possibility of the flexible manipulation of light is the laser-beam shaping.Aim is thereby to transform the intensity profile of a laser beam to a wanted profile. The main topic of this thesis is the modeling and propagation of laser light in paraxial and non-paraxial beam-shaping systems as well as the optimization of these systems by means of a generalized projection algorithm. This algorithm is applied for the optimization by means of aspherical formula or polynomials point-by-point parametrized beam shaping surfaces. It is shown that during the optimization a regardment of diffraction, interference, and abberations is possible. The latter can not only be regarded, but directly used for the beam shaping. Finally it is shown that the aberrations of spherical catalogue lenses are already sufficient for some beam-shaping applications. The efficiency of the developed optimization algorithms is demonstrated both on paraxial and on non-paraxial beam-shaping examples with a numerical aperture of up to 0.62. Finally in the present thesis concepts for the achromatization and for the wave-length multiplexing are introduced, which are based on the application of diverse surfaces and materials with different dispersion. While the achromatization aims to make the optical function of a beam-shaping system wave-length independent, the wavelength multiplexing tries directly to realize different optical functions for diverse design wavelengths. [German] Die Erzeugung massgeschneiderten Lichts steht heute im Mittelpunkt vieler innovativer Anwendungen. Eine Moeglichkeit der flexiblen Manipulation von Licht ist die Laserstrahlformung. Ziel ist es dabei, das Intensitaetsprofil eines Laserstrahls in ein gewuenschtes Profil umzuformen. Schwerpunkt dieser Arbeit ist die Modellierung und Ausbreitung von Laserlicht in paraxialen und nicht-paraxialen Strahlformungssystemen sowie die

  14. Magnetic and Sedimentological Analyses of Sediment Cores from Otsego Lake Reveal Climate and Possible Delta Dynamics Throughout the Holocene

    Science.gov (United States)

    Geiss, C. E.; Hasbargen, L. E.

    2015-12-01

    Otsego Lake (42°43'N, -74°54'W) is a large oligotrophic, monomictic lake in upstate New York that occupies a narrow, N-S trending basin (approx. 13 km length, 2 km width) and has a maximum water depth of approx. 50 m. We collected two sediment cores from a shallow (4 m water depth) bench near the SW shore of the lake. The cores were collected approximately 200 m off-shore from a small stream delta. Age control was established through five 14C AMS-dates obtained from terrestrial plant macrofossils. We analyzed sediments for their magnetic properties (magnetic susceptibility, anhysteretic- and isothermal remanent magnetization, hysteresis properties and coercivity distributions) and performed loss-on-ignition and X-ray analyses to determine the relative abundance of organic matter, quartz and calcite. The watershed of Otsego Lake rests in glacial debris and Devonian shale and limestone. The base of the core (> 9 ka) consists mostly of silt-sized, massive to weakly laminated siliceous and strongly magnetic sediments. Between 8-9 ka the climate warmed sufficiently to allow for the formation of calcareous sediments. Between 8 - 6 ka magnetic minerals are characterized by low abundance and small grainsize, while organic and inorganic carbon increase. Sedimentation rates decrease significantly between 6-2 ka (from ~100 cm/ka to 12-15 cm/ka). During this time interval the relative abundance of quartz increases, sediment becomes slightly more magnetic, and the magnetic grain-size increases as well. We interpret this time period as a low-stand, when lower lake levels allow for the redeposition and possible loss of sediment into the deeper part of the lake, as well as increased terrigenous input from the nearby lakeshore. This lowstand is clearly identified as a strong, continuous reflector in GPR profiles. Sediments younger than 2 ka are characterized by variable abundances of magnetic minerals, with magnetic remanence peaks appearing semi-periodically approximately every

  15. 3D numerical analyses for the quantitative risk assessment of subsidence and water flood due to the partial collapse of an abandoned gypsum mine.

    Science.gov (United States)

    Castellanza, R.; Orlandi, G. M.; di Prisco, C.; Frigerio, G.; Flessati, L.; Fernandez Merodo, J. A.; Agliardi, F.; Grisi, S.; Crosta, G. B.

    2015-09-01

    After the abandonment occurred in the '70s, the mining system (rooms and pillars) located in S. Lazzaro di Savena (BO, Italy), grown on three levels with the method rooms and pillars, has been progressively more and more affected by degradation processes due to water infiltration. The mine is located underneath a residential area causing significant concern to the local municipality. On the basis of in situ surveys, laboratory and in situ geomechanical tests, some critical scenarios were adopted in the analyses to simulate the progressive collapse of pillars and of roofs in the most critical sectors of the mine. A first set of numerical analyses using 3D geotechnical FEM codes were performed to predict the extension of the subsidence area and its interaction with buildings. Secondly 3D CFD analyses were used to evaluated the amount of water that could be eventually ejected outside the mine and eventually flooding the downstream village. The predicted extension of the subsidence area together with the predicted amount of the ejected water have been used to design possible remedial measurements.

  16. Physical and numerical modelling of permafrost dynamic during a climatic cycle: implications for Meuse - Haute-Marne site

    International Nuclear Information System (INIS)

    This manuscript deals about works realized on the permafrost modelling in porous media and its impact on the hydrogeological circulations. These are parts of the Andra's studies on the nuclear waste storage and, on the environmental studies of the Meuse/Haute-Marne (MHM) site. During a climatic cycle, cold periods can generate permafrost (ground with temperature lower than 0 C for 2 consecutive years). This peri-glacial structure propagates towards deep geological layers, and, due to its very low permeability, can stop the flow of water bodies like aquifers. This work presents the elaboration of two numerical models (with Cast3M code (CEA)): (i) a model with thermal conduction, used for the study of a cold wave propagation in porous media with phase transition (water-ice); (ii) a more complex model, managing the thermo-hydraulic coupling of ground phenomenon (conduction, convection and transition of phase). After validation, these two models offer three axes of development: (i) benchmark proposition by the study of two generic test-cases; (ii) study of the local air temperature signal on MHM site: importance of high frequency temperature variations (centennial scale) for permafrost depth and stability; (iii) study of the dynamics of a thermal discontinuity in a typical hydrological system river-plain: closure time of the system by the permafrost according to various parameters (temperatures, geothermal flow, hydrological flow directions). (author)

  17. Climatization

    DEFF Research Database (Denmark)

    Grant, Stephen; Tamason, Charlotte Crim; Jensen, Peter Kjær Mackie

    2015-01-01

    by climate change, in order to reach an intended goal or to distractthe discussion from the real problem which might have a different root course than caused bythe climate change effects. The implications of climatization are currently unclear – particularly to what extent climatizinga disaster might......In recent years, there has been a developing trend of labelling some disasters as ‘climatechange disasters’. In doing so, a discursive phenomenon can emerge that the authors havecoined ‘climatization’ which is specified as framing a disastrous event or degraded environmentalcondition as caused...... in the context of Bangladesh – a country that is expectedto be among the worst affected by climate change and a country in which some peopleclaim the effects of climate change can already be seen. A qualitative field study whichincluded key informant interviews, focus group discussions and a literature review...

  18. A simple object-oriented and open-source model for scientific and policy analyses of the global climate system - Hector v1.0

    Science.gov (United States)

    Hartin, C. A.; Patel, P.; Schwarber, A.; Link, R. P.; Bond-Lamberty, B. P.

    2015-04-01

    Simple climate models play an integral role in the policy and scientific communities. They are used for climate mitigation scenarios within integrated assessment models, complex climate model emulation, and uncertainty analyses. Here we describe Hector v1.0, an open source, object-oriented, simple global climate carbon-cycle model. This model runs essentially instantaneously while still representing the most critical global-scale earth system processes. Hector has a three-part main carbon cycle: a one-pool atmosphere, land, and ocean. The model's terrestrial carbon cycle includes primary production and respiration fluxes, accommodating arbitrary geographic divisions into, e.g., ecological biomes or political units. Hector actively solves the inorganic carbon system in the surface ocean, directly calculating air-sea fluxes of carbon and ocean pH. Hector reproduces the global historical trends of atmospheric [CO2], radiative forcing, and surface temperatures. The model simulates all four Representative Concentration Pathways (RCPs) with equivalent rates of change of key variables over time compared to current observations, MAGICC (a well-known simple climate model), and models from the 5th Coupled Model Intercomparison Project. Hector's flexibility, open-source nature, and modular design will facilitate a broad range of research in various areas.

  19. Analyses of possible changes in intense and extreme wind speeds over northern Europe under climate change scenarios

    DEFF Research Database (Denmark)

    Pryor, Sara; Barthelmie, Rebecca Jane; Clausen, Niels-Erik;

    2012-01-01

    %) in the southwest of the domain and across the central Baltic Sea by the end of the current century. As in prior downscaling of ECHAM4, dynamical downscaling of ECHAM5 indicates a tendency towards increased energy density and thus wind power generation potential over the course of the C21st. However, caution should......21st. Even then, significant changes are indicated only in the SW of the domain and across the central Baltic Sea where there is some evidence for relatively small magnitude increases in the 50 year return period wind speed (of up to 15%). There are marked differences in results based on the two...... Regional Climate Models. Additionally, internal (inherent) variability and initial conditions exert a strong impact on projected wind climates throughout the twenty-first century. Simulations of wind gusts by one of the RCMs (RCA3) indicate some evidence for increased magnitudes (of up to +10...

  20. Characterization of rapid climate changes through isotope analyses of ice and entrapped air in the NEEM ice core

    DEFF Research Database (Denmark)

    Guillevic, Myriam

    Greenland ice core have revealed the occurrence of rapid climatic instabilities during the last glacial period, known as Dansgaard-Oeschger (DO) events, while marine cores from the North Atlantic have evidenced layers of ice rafted debris deposited by icebergs melt, caused by the collapse...... of Northern hemisphere ice sheets, known as Heinrich events. The imprint of DO and Heinrich events is also recorded at mid to low latitudes in different archives of the northern hemisphere. A detailed multi-proxy study of the sequence of these rapid instabilities is essential for understanding the climate...... mechanisms at play. Recent analytical developments have made possible to measure new paleoclimate proxies in Greenland ice cores. In this thesis we first contribute to these analytical developments by measuring the new innovative parameter 17O-excess at LSCE (Laboratoire des Sciences du Climatet de l...

  1. The impacts of climate change and environmental management policies on the trophic regimes in the Mediterranean Sea: Scenario analyses

    Science.gov (United States)

    Lazzari, P.; Mattia, G.; Solidoro, C.; Salon, S.; Crise, A.; Zavatarelli, M.; Oddo, P.; Vichi, M.

    2014-07-01

    The impacts of climate change and environmental management policies on the Mediterranean Sea were analyzed in multi-annual simulations of carbon cycling in a planktonic ecosystem model. The modeling system is based on a high-resolution coupled physical-biogeochemical ocean model that is off-line and forced by medium-resolution global climate simulations and by estimates of continental and river inputs of freshwater and nutrients. The simulations span the periods 1990-2000 and 2090-2100, assuming the IPCC SRES A1B scenario of climatic change at the end of the century. The effects of three different options on land use, mediated through rivers, are also considered. All scenarios indicate that the increase in temperature fuels an increase in metabolic rates. The gross primary production increases approximately 5% over the present-day figures, but the changes in productivity rates are compensated by augmented community respiration rates, so the net community production is stable with respect to present-day figures. The 21st century simulations are characterized by a reduction in the system biomass and by an enhanced accumulation of semi-labile dissolved organic matter. The largest changes in organic carbon production occur close to rivers, where the influence of changes in future nutrient is higher.

  2. Energy and climate change: the main analyses of Regards sur la Terre. An annual publication on sustainable development

    International Nuclear Information System (INIS)

    In November 2006, the French Development Agency, AFD (Agence francaise de developpement) and the Institute for Sustainable Development and International Relations, IDDRI (Institut du developpement durable et des relations internationales) launched an annual publication on sustainable development in a global perspective, Regards sur la Terre, published by Les Presses de Sciences Po (Paris). Regards sur la Terre includes an analysis of the most important international events of the last twelve months in the field of sustainable development, along with a thematic section, which in the first edition focused on energy and climate change. This booklet presents the overall introduction of the 2007 publication and the introduction of its thematic section, as well as a selection of the main chapters dealing with the theme of energy and climate change. Contents: Awakening and crisis of confidence; Reorienting our Societies; Energy in the world: Challenges and prospects; Challenges and constraints for energy supply: The coal hard facts; Satisfying energy growth in emerging countries; Diversifying power generation in China; From Rio to Marrakech: Development in climate negotiations; An international coordination regime come what may; The perspective of developing countries; An American 'point of view'

  3. Preliminary assessment of late quaternary vegetation and climate of southeastern Utah based on analyses of packrat middens

    International Nuclear Information System (INIS)

    Packrat midden sequences from two caves (elevations 1585 and 2195 m; 5200 and 7200 ft) southwest of the Abajo Mountains in southeast Utah record vegetation changes that are attributed to climatic changes occurring during the last 13,000 years. These data are useful in assessing potential future climates at proposed nuclear waste sites in the area. Paleoclimates are reconstructed by defining modern elevational analogs for the vegetation assemblages identified in the middens. Based on the midden record, a climate most extreme from the present occurred prior to approximately 10,000 years before present (BP), when mean annual temperature was probably 3 to 4C (5.5 to 7F) cooler than present. However, cooling could not have exceeded 5C (9F) at 1585 m (5200 ft). Accompanying mean annual precipitation is estimated to have been from 35 to 140% greater than at present, with rainfall concentrated in the winter months. Vegetational changes beginning approximately 10,000 years BP are attributed to increased summer and mean annual temperatures, a decreasing frequency of spring freezes, and a shift from winter- to summer-dominant rainfall. Greater effective moisture than present is inferred at both cave sites from approximately 8000 to 4000 years BP. Modern flora was present at both sites by about 2000 years BP

  4. Numerical-experimental analyses by Hot-Wire method of an alumina cylinder for future studies on thermal conductivity of the fusion breeder materials

    International Nuclear Information System (INIS)

    The determination of the thermal conductivity of breeder materials is one of the main goal in order to find the best candidate material for the fusion reactor technology. Experimental tests have been and will be carried out with a dedicated experimental devices, built at the Department of Civil and Industrial Engineering of the University of Pisa. The methodological approach used in doing that is characterized by two main phases strictly interrelated each other: the first one focused on the experimental evaluation of thermal conductivity of a ceramic material, by means of hot wire method, to be subsequently used in the second phase, based on the test rig method, to determine the thermal conductivity of pebble bed material. To the purpose, two different experimental devices have been designed and built. This paper deals with the first phase of the methodology. In this framework, the equipment set up and built to perform Hot wire tests, the ceramic material (a cylinder of alumina), the experimental procedure and the measured results obtained varying the temperature, are presented and discussed. The experimental campaign has been lead from 50°C up to 400°C. The thermal conductivity of the ceramic material at different bulk temperatures has been obtained in stationary conditions (detected on the basis of the temperature values measured during the experiment). Numerical analyses have been also performed by means of FEM code Ansys©. The numerical results were in quite good agreement with the experimental one, confirming also the reliability of code in reproducing heat transfer phenomena

  5. Isotopic and chemical analyses of a temperate firn core from a Chinese alpine glacier and its regional climatic significance

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Mt. Yulong is the southernmost currently glacier-covered area in Eurasia, including China. There are 19 sub-tropical temperate glaciers on the mountain, controlled by the south-western monsoon climate. In the summer of 1999, a firn core, 10. 10 m long, extending down to glacier ice, was recovered in the accumulation area of the largest glacier, Baishui No. 1. Periodic variations of climatic signals above 7. 8 m depth were apparent, and net accumulation of four years was identified by the annual oscillations of isotopic and ionic composition. The boundaries of annual accumulation were confirmed by higher values of electrical conductivity and pH, and by dirty refreezing ice layers at the levels of summer surfaces. Calculated mean annual net accumulation from 1994/1995 to 1997/1998 was about 900 mm water equivalent. The amplitude of isotopic variations in the profile decreased with increasing depth, and isotopic homogenization occurred below 7. 8 m as a result of meltwater percolation. Variations of δ18O above 7. 8 m showed an approximate correlation with the winter climatic trend at Li Jiang Station, 25 km away. Concentrations of Ca2+ and Mg2+ were much higher than those of Na+ and K+ , indicating that the air masses for precipitation were mainly from a continental source, and that the core material accumulated during the winter period. The close correspondence of C1- and Na+ indicated their common origin. Very low concentrations of SO2-4 and NO3- suggest that pollution caused by human activities is quite low in the area. The mean annual net accumulation in the core and the estimated ablation indicate that the average annual precipitation above the glacier's equilibrium line is 2400 - 3150 mm, but this needs to be confirmed by long term observation of mass balance.

  6. The climate station of the University of Hohenheim: analyses of air temperature and precipitation time series since 1878

    Science.gov (United States)

    Wulfmeyer, Volker; Henning-Müller, Ingeborg

    2006-01-01

    At the University of Hohenheim (UHOH), one of the longest records in Germany concerning meteorological surface data exists. Since the late nineteenth century, time series of several surface variables such as temperature, precipitation, wind and relative humidity have been measured. Particularly, since 1878, almost continuous time series of temperature and precipitation are available.We are focusing our analysis on temperature as well as on precipitation. We demonstrate that the UHOH data provide another homogeneous, and from other sources, independent time record. Its errors are also well specified.Long time series are essential for investigating climate trends as well as statistics of extreme events. We are investigating trends in temperature and compare these to climatologies. We observe an increase in temperature of about 0.6 °C between 1971 and 2000 in comparison to the average between 1878 and 2002. Not only this amount but also the shape of the temperature curve are in striking agreement with trends assessed by the Intergovernmental Panel on Climate Change in the Northern Hemisphere. It shows also the same behavior of the Climate Research Unit (CRU) climatology using the grid point surrounding our measurement site. This demonstrates a low influence of local effects on the temperature trend at our measurement site. It also indicates that temperature fields have a large spatial correlation length. We found a reduction of 2.2 frost days and a reduction of 1.2 ice days per decade. In the summer of 2003, the mean temperature was 21.8 °C, which was 5 standard deviations larger than the mean value of 16.9 °C between 1878 and 2002.The precipitation patterns at our site show a significant increase of precipitation in winter, whereas in summer a trend is not significant. Particularly in winter, we find an increase of 12%. We also detected indications of a shift of precipitation to more extreme values.

  7. Basic Diagnosis and Prediction of Persistent Contrail Occurrence using High-resolution Numerical Weather Analyses/Forecasts and Logistic Regression. Part I: Effects of Random Error

    Science.gov (United States)

    Duda, David P.; Minnis, Patrick

    2009-01-01

    Straightforward application of the Schmidt-Appleman contrail formation criteria to diagnose persistent contrail occurrence from numerical weather prediction data is hindered by significant bias errors in the upper tropospheric humidity. Logistic models of contrail occurrence have been proposed to overcome this problem, but basic questions remain about how random measurement error may affect their accuracy. A set of 5000 synthetic contrail observations is created to study the effects of random error in these probabilistic models. The simulated observations are based on distributions of temperature, humidity, and vertical velocity derived from Advanced Regional Prediction System (ARPS) weather analyses. The logistic models created from the simulated observations were evaluated using two common statistical measures of model accuracy, the percent correct (PC) and the Hanssen-Kuipers discriminant (HKD). To convert the probabilistic results of the logistic models into a dichotomous yes/no choice suitable for the statistical measures, two critical probability thresholds are considered. The HKD scores are higher when the climatological frequency of contrail occurrence is used as the critical threshold, while the PC scores are higher when the critical probability threshold is 0.5. For both thresholds, typical random errors in temperature, relative humidity, and vertical velocity are found to be small enough to allow for accurate logistic models of contrail occurrence. The accuracy of the models developed from synthetic data is over 85 percent for both the prediction of contrail occurrence and non-occurrence, although in practice, larger errors would be anticipated.

  8. Relation between the sedimentary organic record and the climatic oscilations in the Holocene attested by palynofacies and organic geochemical analyses from a pond of altitude in southern Brazil

    Directory of Open Access Journals (Sweden)

    GABRIELLI T. GADENS-MARCON

    2014-09-01

    Full Text Available This paper presents the quantitative and qualitative results obtained from palynofacies and geochemistry analyses carried out on a core covering approximately 8000 years of sedimentation of a pond of altitude located at the mining district of Ametista do Sul, southernmost Brazil. The main objective of this paper is to consider the paleoclimatic and paleoenvironmental significance of these analyses. The hydrological isolation renders this pond climatically sensitive to variations in pluviometric regime and this enabled infer rainfall events during the early Holocene, which was responsible for the beginning of the processes of water accumulation in the gossan and the sedimentation of the pond. Changes in the pattern of moisture over the time become the drier environment, resulting in the intermittent pattern of water depth that currently exists at the site. The fluctuations in water depth are inferred from the frequency of Botryococcus and other algae, which tend to decrease progressively toward the top where the autochthonous elements are replaced by parautochthonous and allochthonous elements. Pseudoschizaea, in turn, appears to act as a biological marker of these transitional intervals. The present results are of great importance for understanding the extent of climate change and its environmental impacts at regional and global levels.

  9. Numerical Simulation of the Effects of Grassland Degradation on the Surface Climate in Overgrazing Area of Northwest China

    Directory of Open Access Journals (Sweden)

    Yanfei Li

    2013-01-01

    Full Text Available The climatic effects of LUCC have been a focus of current researches on global climate change. The objective of this study is to investigate climatic effects of grassland degradation in Northwest China. Based on the stimulation of the conversion from grassland to other land use types during the next 30 years, the potential effects of grassland degradation on regional climate in the overgrazing area of Northwest China from 2010 to 2040 have been explored with Weather Research and Forecasting model (WRF. The analysis results show that grassland will mainly convert into barren land, croplands, and urban land, which accounts for 42%, 48%, and 10% of the total converted grassland area, respectively. The simulation results indicate that the WRF model is appropriate for the simulation of the impact of grassland degradation on climate change. The grassland degradation during the next 30 years will result in the decrease of latent heat flux, which will further lead to the increase of temperature in summer, with an increment of 0.4–1.2°C, and the decrease of temperature in winter, with a decrement of 0.2°C. In addition, grassland degradation will cause the decrease of precipitation in both summer and winter, with a decrement of 4–20 mm.

  10. Numerical Atmospheric-Hydrologic Modeling-Based Flood Frequency Analysis from Future Climate Projections at Cache Creek Watershed, California.

    Science.gov (United States)

    Trinh, T. Q.; Ishida, K.; Fischer, I.; Kavvas, M. L.

    2015-12-01

    Effect of climate change on hydrologic flow regimes, particularly extreme events, necessitates modeling of future flows in order to best inform water resources management. This study simulated future flows in the Cache Creek watershed in California, over the 21st century using a hydro-climate model (WEHY-HCM) forced by future climate projections. The future climate projections, based on four emission scenarios simulated by two GCMs (ECHAM5 and CCSM3) under several initial conditions, were dynamically downscaled using MM5, a regional climate model. The downscaled future precipitation data were bias-corrected before being input into the WEHY model to simulate the detailed flow at hourly intervals along the main Cache Creek branch and its tributaries during 2010-2099. The results suggest an increasing trend in flood magnitudes and their intensities at the outlet of the study region throughout the 21st century. Similarly, estimates of the 100 and 200-year floods increased throughout the study period. The observed differences in the estimated future flood frequencies between the first half and the second half of 21st century may be an evidence of the non-stationarity in the 21st century hydrological regime over the study region.

  11. Reconstructing glacier-based climates of LGM Europe and Russia – Part 1: Numerical modelling and validation methods

    Directory of Open Access Journals (Sweden)

    A. J. Payne

    2007-10-01

    Full Text Available The mountain environments of mid-latitude Europe and Arctic Russia contain widespread evidence of Late-Quaternary glaciers that have been prescribed to the Last Glacial Maximum (LGM. This glacial-geological record has yet to be used to quantitatively reconstruct the LGM climate of these regions. Here we describe a simple glacier-climate model that can be used to derive regional temperature and precipitation information from a known glacier distribution. The model was tested against the present day distribution of glaciers in Europe. The model is capable of adequately predicting the spatial distribution, snowline and equilibrium line altitude climate of glaciers in the Alps, Scandinavia, Caucasus and Pyrenees Mountains. This verification demonstrated that the model can be used to investigate former climates such as the LGM. Reconstructions of LGM climates from proxy evidence are an important method of assessing retrospective general circulation model (GCM simulations. LGM palaeoclimate reconstructions from glacial-geological evidence would be of particular benefit to investigations in Europe and Russia, where to date only fossil pollen data have been used to assess continental-scale GCM simulations.

  12. Reconstructing glacier-based climates of LGM Europe and Russia – Part 1: Numerical modelling and validation methods

    Directory of Open Access Journals (Sweden)

    R. Allen

    2008-11-01

    Full Text Available The mountain environments of mid-latitude Europe and Arctic Russia contain widespread evidence of Late-Quaternary glaciers that have been attributed to the Last Glacial Maximum (LGM. This glacial-geological record has yet to be used to quantitatively reconstruct the LGM climate of these regions. Here we describe a simple glacier-climate model that can be used to derive regional temperature and precipitation information from a known glacier distribution. The model was tested against the present day distribution of glaciers in Europe. The model is capable of adequately predicting the spatial distribution, snowline and equilibrium line altitude climate of glaciers in the Alps, Scandinavia, Caucasus and Pyrenees Mountains. This verification demonstrated that the model can be used to investigate former climates such as the LGM. Reconstructions of LGM climates from proxy evidence are an important method of assessing retrospective general circulation model (GCM simulations. LGM palaeoclimate reconstructions from glacial-geological evidence would be of particular benefit to investigations in Europe and Russia, where to date only fossil pollen data have been used to assess continental-scale GCM simulations.

  13. Numerical climate modeling and verification of selected areas for heat waves of Pakistan using ensemble prediction system

    Science.gov (United States)

    Amna, S.; Samreen, N.; Khalid, B.; Shamim, A.

    2013-06-01

    Depending upon the topography, there is an extreme variation in the temperature of Pakistan. Heat waves are the Weather-related events, having significant impact on the humans, including all socioeconomic activities and health issues as well which changes according to the climatic conditions of the area. The forecasting climate is of prime importance for being aware of future climatic changes, in order to mitigate them. The study used the Ensemble Prediction System (EPS) for the purpose of modeling seasonal weather hind-cast of three selected areas i.e., Islamabad, Jhelum and Muzaffarabad. This research was purposely carried out in order to suggest the most suitable climate model for Pakistan. Real time and simulated data of five General Circulation Models i.e., ECMWF, ERA-40, MPI, Meteo France and UKMO for selected areas was acquired from Pakistan Meteorological Department. Data incorporated constituted the statistical temperature records of 32 years for the months of June, July and August. This study was based on EPS to calculate probabilistic forecasts produced by single ensembles. Verification was done out to assess the quality of the forecast t by using standard probabilistic measures of Brier Score, Brier Skill Score, Cross Validation and Relative Operating Characteristic curve. The results showed ECMWF the most suitable model for Islamabad and Jhelum; and Meteo France for Muzaffarabad. Other models have significant results by omitting particular initial conditions.

  14. A Numerical Simulation Study of Impacts of Historical Land-Use Changes on the Regional Climate in China Since 1700

    Institute of Scientific and Technical Information of China (English)

    LI Qiaoping; DING Yihui; DONG Wenjie

    2007-01-01

    By using the improved regional climate model (BCC_RegCM1.0), a series of modeling experiments are undertaken to investigate the impacts of historical land-use changes (LUCs) on the regional climate in China.Simulations are conducted for 2 years using estimated land-use for 1700, 1800, 1900, 1950, and 1990. The conversion of land cover in these periods was extensive over China, where large areas were altered from forests to either grass or crops, or from grasslands to crops. Results show that, since 1700, historical LUCs have significant effects on regional climate change, with rainfall increasing in the middle and lower reaches of the Yangtze River Basin, Northwest China, and Northeast China, but decreasing by different degrees in other regions. The air temperature shows significant warming over large areas in recent hundred years,especially from 1950 to 1990, which is consistent with the warming caused by increasing greenhouse gases.On the other hand, historical LUCs have obvious effects on mean circulation, with the East Asian winter and summer monsoonal flows becoming more intensive, which is mainly attributed to the amplified temperature difference between ocean and land due to vegetation change. Thus, it would be given more attention to the impacts of LUCs on regional climate change.

  15. Analysing the emission gap between pledged emission reductions under the Cancun Agreements and the 2C climate target

    Energy Technology Data Exchange (ETDEWEB)

    Den Elzen, M.G.J.; Roelfsema, M.; Hof, A.F. [Netherlands Environmental Assessment Agency PBL, Den Haag (Netherlands); Boettcher, H. [Institute for Applied Systems Analysis IIASA, Laxenburg (Austria); Grassi, G. [Joint Research Centre JRC, European Commission, Ispra (Italy)

    2012-04-15

    In the Cancun Agreements, Annex I Parties (industrialised countries) and non-Annex I Parties (developing countries) made voluntary pledges to reduce greenhouse gas emissions by 2020. The Cancun Agreements also state a long-term target of limiting temperature increase to a maximum of 2C above pre-industrial levels. This report is an update of the PBL report 'Evaluation of the Copenhagen Accord', which similar to earlier studies showed that there is a possible gap in emissions between the emission level resulting from the pledges and the level necessary to achieve the 2C target. The updates involve new information on many topics that have become available over the last two years, including updated national business-as-usual emission projections as provided by the countries themselves, and more information on uncertainties and on factors influencing the size of the emission gap. In this context, the main objective of this report can be formulated as follows: This report analyses the effect of the pledges put forward by the Parties in the Cancun Agreements on the emission gap, taking into account all the new information available. It pays specific attention to uncertainties and risks and describes in more detail the emission implications of the pledges and actions of the 12 largest emitting countries or regions.

  16. Exploiting the weekly cycle as observed over Europe to analyse aerosol indirect effects in two climate models

    Directory of Open Access Journals (Sweden)

    J. Quaas

    2009-05-01

    Full Text Available A weekly cycle in aerosol pollution and meteorological quantities is observed over Europe. In the present study we exploit this effect to analyse aerosol-cloud-radiation interactions. A weekly cycle is imposed on anthropogenic emissions in two general circulation models that include parameterizations of aerosol cycles and cloud microphysics. It is found that the simulated weekly cycles in sulfur dioxide, sulfate, and aerosol optical depth in both models agree reasonably well with the observed ones indicating model skill in simulating the aerosol cycle. A distinct weekly cycle in cloud droplet number concentration is demonstrated in both observations and models. For other variables, such as cloud liquid water path, cloud cover, top-of-the-atmosphere radiation fluxes, precipitation, and surface temperature, large variability and contradictory results between observations, model simulations, and model control simulations without a weekly cycle in emissions prevent us from reaching any firm conclusions about the potential aerosol impact on meteorology or the realism of the modeled second aerosol indirect effects.

  17. Exploiting the weekly cycle as observed over Europe to analyse aerosol indirect effects in two climate models

    Directory of Open Access Journals (Sweden)

    H. Joos

    2009-11-01

    Full Text Available A weekly cycle in aerosol pollution and some meteorological quantities is observed over Europe. In the present study we exploit this effect to analyse aerosol-cloud-radiation interactions. A weekly cycle is imposed on anthropogenic emissions in two general circulation models that include parameterizations of aerosol processes and cloud microphysics. It is found that the simulated weekly cycles in sulfur dioxide, sulfate, and aerosol optical depth in both models agree reasonably well with those observed indicating model skill in simulating the aerosol cycle. A distinct weekly cycle in cloud droplet number concentration is demonstrated in both observations and models. For other variables, such as cloud liquid water path, cloud cover, top-of-the-atmosphere radiation fluxes, precipitation, and surface temperature, large variability and contradictory results between observations, model simulations, and model control simulations without a weekly cycle in emissions prevent us from reaching any firm conclusions about the potential aerosol impact on meteorology or the realism of the modelled second aerosol indirect effects.

  18. Case study Sylt - Consequences and integrated assessment of climate change. Final report; Klimaaenderung und Kueste. Fallstudie Sylt - Integrative Analyse und Bewertung der Folgen von Klimaaenderungen. Endbericht

    Energy Technology Data Exchange (ETDEWEB)

    Fraenzle, O.; Sterr, H.; Daschkeit, A.

    2001-05-01

    This final report deals with the structure of the 'case study Sylt' against the background of climate change and possible consequences. In cooperation with the other projects of the case study an instrument is developed which maintains interdisciplinary communication and cooperation. First the 'System Sylt' is described to identify and specify the relevant aspects of functional relationships between the natural and the social system. The focal points are (1) the first-order impacts of climate change, (2) the potential ecological changes in the near future and (3) the image of the North-Sea island Sylt. With regard to the image of Sylt we find some discrepancies existing between a statical respectively a dynamical view; these discrepancies are inherent parts of the future development. All results are seen in the context of 'Integrated Coastal Zone Management' (ICZM) to derive general and specific recommendations for political action and further research. (orig.) [German] Vor dem Hintergrund von Annahmen bezueglich der zukuenftigen klimatischen Entwicklung werden die Konzeption sowie die Vorgehensweise der integrativen Analyse im Rahmen der Fallstudie Sylt dargestellt. Unter Anbindung an das Sylt-GIS wird ein Instrument entwickelt und erprobt, das die (bislang seltene) fachuebergreifende Analyse von Klimafolgen unterstuetzt. Diese muendet zunaechst in eine Darstellung des 'Systems Sylt' auf der Grundlage der wichtigsten Prozesse und Randbedingungen. Die auf dieser Basis identifizierten Kernberichte des 'Systems Sylt' werden in einem weiteren exemplarisch und unter Einbezug des in den disziplinaeren Teilvorhaben der Fallstudie erarbeiteten Wissens einer vertiefenden Analyse unterzogen. Dabei wird erstens auf den Bereich der Folgen eines moeglichen Klimawandels eingegangen, zweitens auf vergangene und zukuenftig moegliche oekologische Veraenderungen und drittens auf das Sylt-Image. Durch eine detailliertere Analyse des

  19. The CM SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite

    Directory of Open Access Journals (Sweden)

    M. Schröder

    2012-09-01

    Full Text Available The "European Organisation for the Exploitation of Meteorological Satellites" (EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF aims at the provision and sound validation of well documented Climate Data Records (CDRs in sustained and operational environments. In this study, a total column water vapour (WVPA climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I, a climatology of WVPA has been generated within the Hamburg Ocean-Atmosphere Fluxes and Parameters from Satellite (HOAPS framework. Within a research and operation transition activity the HOAPS data and operations capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, kriging, has been developed and applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses and from the Japan Meteorological Agency (JMA-JRA. This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m−2. The absolute bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m−2. For the period 1991–2006, the root mean square error (RMSE to both reanalysis is approximately 2 kg m−2. As SSM/I WVPA and radiances are assimilated in JMA and all

  20. The CM SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite

    Directory of Open Access Journals (Sweden)

    M. Schröder

    2013-03-01

    Full Text Available The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF aims at the provision and sound validation of well documented Climate Data Records (CDRs in sustained and operational environments. In this study, a total column water vapour path (WVPA climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I, a climatology of WVPA has been generated within the Hamburg Ocean–Atmosphere Fluxes and Parameters from Satellite (HOAPS framework. Within a research and operation transition activity the HOAPS data and operation capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, namely kriging, has been applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses and from the Japan Meteorological Agency (JMA–JRA. This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m−2. The absolute value of the bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m−2. For the period 1991–2006, the root mean square error (RMSE for both reanalyses is approximately 2 kg m−2. As SSM/I WVPA and radiances are assimilated into JMA and all ECMWF analyses and

  1. A Moving Coordinate Numerical Method for Analyses of Electromagneto-Mechanical Coupled Behavior of Structures in a Strong Magnetic Field Aiming at Application to Tokamak Structures

    Science.gov (United States)

    Li, Weixin; Yuan, Zhensheng; Chen, Zhenmao

    2014-12-01

    Analysis of the electromagneto-mechanical coupling effect contributes greatly to the high accuracy estimation of the EM load of many EM devices, such as a tokamak structure during plasma disruption. This paper presents a method for the numerical analysis of the electromagneto-mechanical coupling effect on the basis of Maxwell's equations in the Lagrangian description and staggered load transfer scheme, which can treat the coupled behaviors of magnetic damping and magnetic stiffness effects at the same time. Codes were developed based on the ANSYS development platform and were applied to solve two typical numerical examples: the TEAM Problem 16 and dynamic behavior analysis of a shallow arch under electromagnetic force. The good consistency of numerical results and experimental data demonstrates the validity and accuracy of the proposed method and the related numerical codes.

  2. Mathematical and numerical analysis of hyper-elastic systems and introduction of plasticity; Analyse mathematique et numerique de systemes hyperelastiques et introduction de la plasticite

    Energy Technology Data Exchange (ETDEWEB)

    Kluth, G

    2008-12-15

    The goal is to model mathematically and numerically the dynamic phenomenons for solids in finite plasticity. We suggest a model that we call hyper-elasto-plastic based on hyper-elastic systems of conservation laws and on the use of an equation of state that we have constructed so as to achieve the plastic yield criterion of Von Mises. This model gives exact (analytic) solutions with shock split to flyer-plate experiments. The mathematical analysis of this model is done (hyperbolicity, characteristic fields, involutions and entropy). In the numerical part, we give 1D and 2D Lagrangian schemes which satisfy an entropy criterion. Moreover, thanks to a special discretization of the equations on deformation gradient, we satisfy some discrete involutions. In this work, the degeneracy of the solid model into hydrodynamic models is studied at the continuous level, and achieved at the numerical one. On different problems, we show the validity of our model and our numerical schemes. (author)

  3. Integrated Assessment on Effects of Short-Lived Climate Pollutants (SLCPs) in Asia based on Numerical Models

    Science.gov (United States)

    Takemura, T.; Sudo, K.; Ueda, K.; Masutomi, Y.; Watanabe, S.; Nakata, M.; Takahashi, H. G.; Goto, D.

    2015-12-01

    Air pollution over the Asian region is a serious social problem. For example, activities of the Climate and Clean Air Coalition (CCAC) under the UNFCCC focus on raising awareness and improving scientific understanding of short-lived climate pollutant (SLCP) impacts and mitigation strategies. Our Japanese research project is searching an optimum reduction path of SLCPs considering climate change, health impacts, and agricultural damages. For this purpose, we use aerosol and chemistry models, SPRINTARS and CHASER, respectively, which have been developed by our group, coupled with a general circulation model, MIROC. In the phase 1 of this project, changes in concentrations and radiative forcing of each major SLCPs originating from China, east Asia, southeast Asia, and south Asia in the last 30 years are estimated with the models. Transient simulations along the new emission scenario, SSPs (Shared Socio-economic Pathways) are executed using the MIROC-SPRINTARS/CHASER with ocean circulation in the phase 2 to analyze full feedbacks including hydrological cycle affected by SLCPs. These simulated results will be utilized to estimate health and agricultural impacts of SLCPs. In this presentation, we discuss the optimum reduction path of SLCPs taking both mitigation of global warming and air pollution into consideration. Acknowledgements: Simulations in this study were executed with the supercomputer system of the National Institute for Environmental Studies, Japan. This study is partly supported by the Environment Research and Technology Development Fund (S-12-3) of the Ministry of the Environment, Japan and JSPS KAKENHI Grant Number 15H01728 and 15K12190.

  4. Modeling and numerical analysis of non-equilibrium two-phase flows; Modelisation et analyse numerique des ecoulements diphasiques en desequilibre

    Energy Technology Data Exchange (ETDEWEB)

    Rascle, P.; El Amine, K. [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1997-12-31

    We are interested in the numerical approximation of two-fluid models of nonequilibrium two-phase flows described by six balance equations. We introduce an original splitting technique of the system of equations. This technique is derived in a way such that single phase Riemann solvers may be used: moreover, it allows a straightforward extension to various and detailed exchange source terms. The properties of the fluids are first approached by state equations of ideal gas type and then extended to real fluids. For the construction of numerical schemes , the hyperbolicity of the full system is not necessary. When based on suitable kinetic unwind schemes, the algorithm can compute flow regimes evolving from mixture to single phase flows and vice versa. The whole scheme preserves the physical features of all the variables which remain in the set of physical states. Several stiff numerical tests, such as phase separation and phase transition are displayed in order to highlight the efficiency of the proposed method. The document is a PhD thesis divided in 6 chapters and two annexes. They are entitled: 1. - Introduction (in French), 2. - Two-phase flow, modelling and hyperbolicity (in French), 3. - A numerical method using upwind schemes for the resolution of two-phase flows without exchange terms (in English), 4. - A numerical scheme for one-phase flow of real fluids (in English), 5. - An upwind numerical for non-equilibrium two-phase flows (in English), 6. - The treatment of boundary conditions (in English), A.1. The Perthame scheme (in English) and A.2. The Roe scheme (in English). 136 refs. This document represents a PhD thesis in the speciality Applied Mathematics presented par Khalid El Amine to the Universite Paris 6.

  5. Petroleum system and thermal history of the Upper Rhine Graben : implications from organic geochemical analyses, oil-source rock correlations and numerical modelling

    OpenAIRE

    Böcker, Johannes

    2015-01-01

    The Upper Rhine Graben (URG) forms the central section of the European Cenozoic Rift System and is a mature hydrocarbon province. During previous exploration periods, about 50 oil fields and several gas fields were discovered accompanied by a huge number of exploration and production wells and numerous seismic profiles. Surprisingly, in 2003 a geothermal well found oil in the Buntsandstein reservoir and discovered unexpectedly the Römerberg oil field, which promptly doubled the total recovera...

  6. Numeric age determination for investigations of climate variability. Final report; Numerische Altersbestimmungen fuer Untersuchungen zur Klimavariabilitaet. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Geyh, M.A.

    2002-04-20

    Studies on the palaeoclimatic variability must be based on a reliable chronological platform using absolute or phsical dates. The Institute for Geoscientific Research in Hannover delivered {sup 14}C (and {sup 230}Th/U) dates for palaeoclimatic projects. The University of Stuttgart-Hohenheim used 40 {sup 14}C dates in order to investigate the Holocene vegetation history of the plateau of Tibet. Additional 17 {sup 14}C dates were determined to estimate the anthropogenic aerosol input in Europe in prehistoric and historic times. Geomorphologic and pedologic aspects of climate research within the Highlands of Central Asia have been studied by the University in Goettingen using 104 {sup 14}C dates. The causes of the dramatic deterioration of the human living conditions due to the rapid growth of raised bogs in northern Germany during the middle Holocene was the research topic of the Institute of Coastal Research in Wilhelmshaven. 131 {sup 14}C dates proved that this long-term process is only indirectly related to the global climate change. The Institute of Geoscientific Research in Hannover studied the reliability of {sup 230}Th/U dates of lacustrine sediments form the Altiplano in South America. It applied 24 {sup 14}C dates in order to explain the dispute of the climatic variability in this region. (orig.) [German] Studien zur Klimavariabilitaet sind auf absolute oder wenigstens physikalische Alter angewiesen. Die Sektion 3 der GGA lieferte {sup 14}C- (und {sup 230}Th/U-)Daten fuer palaeoklimatische Untersuchungen im Rahmen des BMBF-Forschungsprogramms 'Klimavariabilitaet'. Die Arbeitsgruppe (AG) der Universitaet Hohenheim (Prof. Dr. B. Frenzel) verwendete 40 {sup 14}C-Daten, um unterschiedliche Vorstellungen zur holozaenen Vegetationsgeschichte des Hochlands von Tibet klaeren zu helfen. Weitere 17 {sup 14}C-Daten wurden zur Abschaetzung des anthropogenen Aerosol-Eintrags in praehistorischer und geschichtlicher Zeit in Europa bestimmt. Die geomorphologisch

  7. Macro economic analyses related to the White Paper No 21 (2011-2012). Norwegian Climate Policy.; Makroanalyser i tilknytning til Klimameldingen 2012

    Energy Technology Data Exchange (ETDEWEB)

    Faehn, Taran; Jacobsen, Karl

    2012-11-01

    We report results from analyses performed for the Ministry of Finance and the Ministry of the Environment of specified climate policy scenarios. The results are computed by means of the model MSG-TECH, which is a computable general equilibrium model that allows for technological abatement options. All the scenarios model the participation in EU emissions trading scheme (ETS), which implies obligations of the firms to mitigate or purchase allowances. The scenarios also include the Kyoto commitments and the Norwegian government's pledges in the wake of the Copenhagen negotiations 2010 to reduce domestic emissions by 30 per cent and 100 per cent by 2020 and 2050, respectively. These ambitions can be met by exploiting international green mechanisms like CDM project funding. The studied scenarios differ in their assumptions about domestic emission prices. None of the scenarios obtain the ambitions set by the Parliament's Climate Agreement in 2008, corresponding to reductions of between 12 and 14 million tons from the reference in 2020. The most ambitious regime in this analysis results in a cut of 4.3 million tons CO{sub 2} equivalents in 2020, while the least ambitious obtains 1.6 million abated tons. In 2050 the cuts constitute between 5.8 and 8.9 million tons CO{sub 2} equivalents. The scenarios P10 and P20 assume a uniform carbon price of all Kyoto gas emissions (except emissions from agriculture). In the former, the uniform price corresponds to the estimated global marginal costs of avoiding a temperature increase above two degrees C. It is operationalised to 280 Nok in 2020 and 1020 Nok in 2050, respectively (in real 2011-prices). This implies that EU ETS sources pay a tax on top of the ETS price that equalise the carbon price within the rest of the economy. This scenario results in a domestic abatement of 2.0 million tons in 2020 and 8.9 million tons in 2050. In the second scenario, the uniform carbon price is assumed to increase faster until 2020

  8. Guidebook for territories' support in the analysis of their socio-economical vulnerability to climate change; Guide d'accompagnement des territoires pour l'analyse de leur vulnerabilite socio-economique au changement climatique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The work of the inter-ministerial group 'Impacts of Climate Change, Adaptation and Associated Costs for France', which met between March 2007 and October 2009, led to a sector-based assessment of all climate change related impacts and of associated adaptation measures. The aim was to obtain quantified elements that could underpin public policy decision-making and especially development of the National Adaptation Plan. While the sectoral analyses focused on quantifying the costs of adaptation, the approach of the 'Territories' group, co-steered by the Datar (regional development delegation) and Ademe (agency for energy management and environment), addressed the subject of interactions between players and activities, both spatial (sharing of resources between different uses, etc.) and temporal (transition from one situation to another, etc.) and the corresponding means for adjustment. It was in this context that the SOeS proposed a methodology for diagnosis of the socio-economic vulnerability of a given sub-national territory in the face of climate change. This document provides a broad-brush outline of the accompanying guidelines developed by Sogreah Consultants SAS for use by local players. A three step approach is followed to draw up the vulnerability profile of a territory: 1 - characterising the territory by the identification of the priority activities and physical features; 2 - using the analysis tools to produce a matrix of indices of vulnerability to climate change per hazard; 3 - drawing up an initial vulnerability profile by bringing together the information from the matrix and that from feedback, either by activity or group of activities, or by environment, depending on aims. The profile leads to identification of the important issues as well as allowing identification of potential impacts to be studied in more depth. Guidelines were tested in three pilot territories facing different climate change issues: Wateringues, in the Nord

  9. Interactions between Climate, Socioeconomics, and Land Dynamics in Qinghai Province, China: A LUCD Model-Based Numerical Experiment

    Directory of Open Access Journals (Sweden)

    Xiangzheng Deng

    2013-01-01

    Full Text Available This simulation-based research produces a set of forecast land use data of Qinghai Province, China, applying the land use change dynamics (LUCD model. The simulation results show that the land use pattern will almost keep being consistent in the period from 2010 to 2050 with that in 2000 in Qinghai Province. Grassland and barren or sparsely vegetated land will cover more than 80% of the province’s total area. The land use change will be inconspicuous in the period from 2010 to 2050 involving only 0.49% of the province’s land. The expansion of urban and built-up land, grassland, and barren or sparsely vegetated land and the area reduction of mixed dryland/irrigated cropland and pasture, water bodies, and snow or ice will dominate land use changes of the case study area. The changes of urban and built-up land and mixed dryland/irrigated cropland and pasture will slow down over time. Meanwhile, the change rates of water bodies, snow and ice, barren or sparsely vegetated land, and grassland will show an inverted U-shaped trajectory. Except for providing underlying surfaces for RCMs for future climate change assessment, this empirical research of regional land use change may enhance the understanding of land surface system dynamics.

  10. Hydrologic and climatic implications of stable isotope and minor element analyses of authigenic calcite silts and gastropod shells from a mid-Pleistocene pluvial lake, Western Desert, Egypt

    Science.gov (United States)

    Kieniewicz, Johanna M.; Smith, Jennifer R.

    2007-11-01

    Authigenic calcite silts at Wadi Midauwara in Kharga Oasis, Egypt, indicate the prolonged presence of surface water during the Marine Isotope Stage 5e pluvial phase recognized across North Africa. Exposed over an area of ˜ 4.25 km 2, these silts record the ponding of water derived from springs along the Libyan Plateau escarpment and from surface drainage. The δ 18O values of these lacustrine carbonates (- 11.3‰ to - 8.0‰ PDB), are too high to reflect equilibrium precipitation with Nubian aquifer water or water of an exclusively Atlantic origin. Mg/Ca and Sr/Ca of the silts have a modest negative covariance with silt δ 18O values, suggesting that the water may have experienced the shortest residence time in local aquifers when the water δ 18O values were highest. Furthermore, intra-shell δ 18O, Sr/Ca, and Ba/Ca analyses of the freshwater gastropod Melanoides tuberculata are consistent with a perennially fresh water source, suggesting that strong evaporative effects expected in a monsoonal climate did not occur, or that dry season spring flow was of sufficient magnitude to mute the effects of evaporation. The input of a second, isotopically heavier water source to aquifers, possibly Indian Ocean monsoonal rain, could explain the observed trends in δ 18O and minor element ratios.

  11. Numerical insight into the seismic behavior of eight masonry towers in Northern Italy: FE pushover vs non-linear dynamic analyses

    Science.gov (United States)

    Milani, Gabriele; Valente, Marco

    2015-12-01

    This study presents some FE results regarding the behavior under horizontal loads of eight existing masonry towers located in the North-East of Italy. The towers, albeit unique for geometric and architectural features, show some affinities which justify a comparative analysis, as for instance the location and the similar masonry material. Their structural behavior under horizontal loads is therefore influenced by geometrical issues, such as slenderness, walls thickness, perforations, irregularities, presence of internal vaults, etc., all features which may be responsible for a peculiar output. The geometry of the towers is deduced from both existing available documentation and in-situ surveys. On the basis of such geometrical data, a detailed 3D realistic mesh is conceived, with a point by point characterization of each single geometric element. The FE models are analysed under seismic loads acting along geometric axes of the plan section, both under non-linear static (pushover) and non-linear dynamic excitation assumptions. A damage-plasticity material model exhibiting softening in both tension and compression, already available in the commercial code Abaqus, is used for masonry. Pushover analyses are performed with both G1 and G2 horizontal loads distribution, according to Italian code requirements, along X+/- and Y+/- directions. Non-linear dynamic analyses are performed along both X and Y directions with a real accelerogram scaled to different peak ground accelerations. Some few results are presented in this paper. It is found that the results obtained with pushover analyses reasonably well fit expensive non-linear dynamic simulations, with a slightly less conservative trend.

  12. Numerical insight into the seismic behavior of eight masonry towers in Northern Italy: FE pushover vs non-linear dynamic analyses

    International Nuclear Information System (INIS)

    This study presents some FE results regarding the behavior under horizontal loads of eight existing masonry towers located in the North-East of Italy. The towers, albeit unique for geometric and architectural features, show some affinities which justify a comparative analysis, as for instance the location and the similar masonry material. Their structural behavior under horizontal loads is therefore influenced by geometrical issues, such as slenderness, walls thickness, perforations, irregularities, presence of internal vaults, etc., all features which may be responsible for a peculiar output. The geometry of the towers is deduced from both existing available documentation and in-situ surveys. On the basis of such geometrical data, a detailed 3D realistic mesh is conceived, with a point by point characterization of each single geometric element. The FE models are analysed under seismic loads acting along geometric axes of the plan section, both under non-linear static (pushover) and non-linear dynamic excitation assumptions. A damage-plasticity material model exhibiting softening in both tension and compression, already available in the commercial code Abaqus, is used for masonry. Pushover analyses are performed with both G1 and G2 horizontal loads distribution, according to Italian code requirements, along X+/− and Y+/− directions. Non-linear dynamic analyses are performed along both X and Y directions with a real accelerogram scaled to different peak ground accelerations. Some few results are presented in this paper. It is found that the results obtained with pushover analyses reasonably well fit expensive non-linear dynamic simulations, with a slightly less conservative trend

  13. Numerical insight into the seismic behavior of eight masonry towers in Northern Italy: FE pushover vs non-linear dynamic analyses

    Energy Technology Data Exchange (ETDEWEB)

    Milani, Gabriele, E-mail: milani@stru.polimi.it, E-mail: gabriele.milani@polimi.it; Valente, Marco [Department of Architecture, Built Environment and Construction Engineering (ABC), Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)

    2015-12-31

    This study presents some FE results regarding the behavior under horizontal loads of eight existing masonry towers located in the North-East of Italy. The towers, albeit unique for geometric and architectural features, show some affinities which justify a comparative analysis, as for instance the location and the similar masonry material. Their structural behavior under horizontal loads is therefore influenced by geometrical issues, such as slenderness, walls thickness, perforations, irregularities, presence of internal vaults, etc., all features which may be responsible for a peculiar output. The geometry of the towers is deduced from both existing available documentation and in-situ surveys. On the basis of such geometrical data, a detailed 3D realistic mesh is conceived, with a point by point characterization of each single geometric element. The FE models are analysed under seismic loads acting along geometric axes of the plan section, both under non-linear static (pushover) and non-linear dynamic excitation assumptions. A damage-plasticity material model exhibiting softening in both tension and compression, already available in the commercial code Abaqus, is used for masonry. Pushover analyses are performed with both G1 and G2 horizontal loads distribution, according to Italian code requirements, along X+/− and Y+/− directions. Non-linear dynamic analyses are performed along both X and Y directions with a real accelerogram scaled to different peak ground accelerations. Some few results are presented in this paper. It is found that the results obtained with pushover analyses reasonably well fit expensive non-linear dynamic simulations, with a slightly less conservative trend.

  14. Localization and analysis of error sources for the numerical SIL proof; Lokalisierung und Analyse von Fehlerquellen beim numerischen SIL-Nachweis

    Energy Technology Data Exchange (ETDEWEB)

    Duepont, D.; Litz, L. [Technische Univ. Kaiserslautern (Germany). Lehrstuhl fuer Automatisierungstechnik; Netter, P. [Infraserv GmbH und Co. Hoechst KG, Frankfurt am Main (Germany)

    2008-07-01

    According to the standard IEC 61511 each safety-related loop is assigned to one of the four Safety Integrity Levels (SILs). For every safety-related loop a SIL-specific Probability of Failure on Demand (PFD) must be proven. Usually, the PFD calculation is performed based upon the failure rates of each loop component aided by commercial software tools. However, this bottom-up approach suffers from many uncertainties. Especially, a lack of reliable failure rate data causes many problems. Reference data collected in different environments are available to solve this situation. However, this pragmatism leads to a PFD bandwidth, not to a single PFD value as desired. In order to make a decision for a numerical value appropriate for the chemical and pharmaceutical process industry a data ascertainment has been initiated by the European NAMUR. Its results display large deficiencies for the bottom-up approach. The error sources leading to this situation are located and analyzed. (orig.)

  15. 3D Numerical Simulation of the Geothermal Field of Permafrost at Salluit in Nunavik, Québec, in Response to Climate Warming. Research in Progress.

    Science.gov (United States)

    Fortier, R.; Allard, M.; Gagnon, O.

    2002-12-01

    survey aims at providing information on the geological and geotechnical characteristics of permafrost. Thermistor cables in deep boreholes, meteorological stations, dataloggers for the measurement of surface temperature, and thermal probes have been also installed in the valley. Air photographs will be used to produce a digital terrain model of the valley. This integrated multi-technique approach is essential for properly assessing the permafrost conditions in the valley. The study will provide the data needed for the development of a 3D model of permafrost conditions in the valley. A 3D numerical simulation of the geothermal field of permafrost in the valley will be then undertaken. This simulation is a major challenge giving the size of the thermal field and the variability in permafrost conditions. The impacts of climate warming on the thermal field of permafrost will be simulated and predicted by forcing the surface temperature to increase following different scenarios of climate warming. It is planned to combine the geotechnical properties and the simulation of the geothermal field of permafrost in order to define threshold values of permafrost strength and slope instability and set a pre-warning scheme of permafrost temperature in case of further warming in the coming years. The monitoring of permafrost temperature will be continued in the future. If the scheme is reached, actions can be then undertaken to mitigate the impacts of climate warming on the infrastructures and protect the population of Salluit.

  16. Analysis and numerical modeling of the global free infra-gravity wave climate for the SWOT mission

    Science.gov (United States)

    Ardhuin, Fabrice; Aucan, Jérome; Rawat, Arshad

    2013-04-01

    All sea level variations of the order of 1 cm at scales under 30 km are of great interest for the future Surface Water Ocean Topography (SWOT) satellite mission. That satellite should provide high-resolution maps of the sea surface height for analysis of meso to sub-mesoscale currents, but that will require a filtering of all gravity wave motions in the data. Free infragravity waves (FIGWs) are generated and radiate offshore when swells and/or wind seas and their associated bound infragravity waves impact exposed coastlines. Free infragravity waves have dominant periods comprised between 1 and 10 minutes and horizontal wavelengths of up to tens of kilometers. Given the length scales of the infragravity waves wavelength and amplitude, the infragravity wave field will can a significant fraction the signal measured by the future SWOT mission. In this study, we analyze the data from recovered bottom pressure recorders of the Deep-ocean Assessment and Reporting of Tsunami (DART) program. This analysis includes data spanning several years between 2006 and 2010, from stations at different latitudes in the North and South Pacific, the North Atlantic, the Gulf of Mexico and the Caribbean Sea. We present and discuss the following conclusions: (1) The amplitude of free infragravity waves can reach several centimeters, higher than the precision sought for the SWOT mission. (2) The free infragravity signal is higher in the Eastern North Pacific than in the Western North Pacific, possibly due to smaller incident swell and seas impacting the nearby coastlines. (3) Free infragravity waves are higher in the North Pacific than in the North Atlantic, possibly owing to different average continental shelves configurations in the two basins. (4) There is a clear seasonal cycle at the high latitudes North Atlantic and Pacific stations that is much less pronounced or absent at the tropical stations, consistent with the generation mechanism of free infragravity waves. Our numerical model

  17. Analysis of the global free infra-gravity wave climate for the SWOT mission, and preliminary results of numerical modelling

    Science.gov (United States)

    Rawat, A.; Aucan, J.; Ardhuin, F.

    2012-12-01

    All sea level variations of the order of 1 cm at scales under 30 km are of great interest for the future Surface Water Ocean Topography (SWOT) satellite mission. That satellite should provide high-resolution maps of the sea surface height for analysis of meso to sub-mesoscale currents, but that will require a filtering of all gravity wave motions in the data. Free infragravity waves (FIGWs) are generated and radiate offshore when swells and/or wind seas and their associated bound infragravity waves impact exposed coastlines. Free infragravity waves have dominant periods comprised between 1 and 10 minutes and horizontal wavelengths of up to tens of kilometers. Given the length scales of the infragravity waves wavelength and amplitude, the infragravity wave field will can a significant fraction the signal measured by the future SWOT mission. In this study, we analyze the data from recovered bottom pressure recorders of the Deep-ocean Assessment and Reporting of Tsunami (DART) program. This analysis includes data spanning several years between 2006 and 2010, from stations at different latitudes in the North and South Pacific, the North Atlantic, the Gulf of Mexico and the Caribbean Sea. We present and discuss the following conclusions: (1) The amplitude of free infragravity waves can reach several centimeters, higher than the precision sought for the SWOT mission. (2) The free infragravity signal is higher in the Eastern North Pacific than in the Western North Pacific, possibly due to smaller incident swell and seas impacting the nearby coastlines. (3) Free infragravity waves are higher in the North Pacific than in the North Atlantic, possibly owing to different average continental shelves configurations in the two basins. (4) There is a clear seasonal cycle at the high latitudes North Atlantic and Pacific stations that is much less pronounced or absent at the tropical stations, consistent with the generation mechanism of free infragravity waves. Our numerical model

  18. School climate and delinquency among Chinese adolescents: analyses of effortful control as a moderator and deviant peer affiliation as a mediator.

    Science.gov (United States)

    Bao, Zhenzhou; Li, Dongping; Zhang, Wei; Wang, Yanhui

    2015-01-01

    School climate is the quality and character of school life and reflects the norms, goals, values, interpersonal relationships, teaching and learning practices, and the organizational structure of a school. There is substantial literature documenting the negative association between positive school climate and adolescent delinquency, but little is known about the moderating and mediating mechanisms underlying this relationship. The aim of this study was to examine whether the direct and indirect pathways between school climate and adolescent delinquency would be moderated by effortful control. A sample of 2,758 Chinese adolescents (M age = 13.53 years, SD = 1.06) from 10 middle schools completed anonymous questionnaires regarding school climate, effortful control, deviant peer affiliation, and delinquency. After gender, age, geographical area, and socioeconomic status were included as covariates, the results revealed that school climate was significantly associated with adolescent delinquent behavior. This direct association was moderated by effortful control, such that the negative relationship between positive school climate and delinquency was only significant among adolescents low in effortful control. Moreover, the indirect association between school climate and delinquency via deviant peer affiliation was also moderated by effortful control. Specifically, the moderating effect of effortful control was not only manifested in the relationship between school climate and deviant peer affiliation, but also in the relationship between deviant peer affiliation and delinquency. These findings contribute to understanding the mechanisms through which positive school climate might reduce delinquent behavior and have important implications for prevention efforts aimed at diminishing adolescent delinquency.

  19. Basic Diagnosis and Prediction of Persistent Contrail Occurrence using High-resolution Numerical Weather Analyses/Forecasts and Logistic Regression. Part II: Evaluation of Sample Models

    Science.gov (United States)

    Duda, David P.; Minnis, Patrick

    2009-01-01

    Previous studies have shown that probabilistic forecasting may be a useful method for predicting persistent contrail formation. A probabilistic forecast to accurately predict contrail formation over the contiguous United States (CONUS) is created by using meteorological data based on hourly meteorological analyses from the Advanced Regional Prediction System (ARPS) and from the Rapid Update Cycle (RUC) as well as GOES water vapor channel measurements, combined with surface and satellite observations of contrails. Two groups of logistic models were created. The first group of models (SURFACE models) is based on surface-based contrail observations supplemented with satellite observations of contrail occurrence. The second group of models (OUTBREAK models) is derived from a selected subgroup of satellite-based observations of widespread persistent contrails. The mean accuracies for both the SURFACE and OUTBREAK models typically exceeded 75 percent when based on the RUC or ARPS analysis data, but decreased when the logistic models were derived from ARPS forecast data.

  20. Interdiffusion of the aluminum magnesium system. Quantitative analysis and numerical model; Interdiffusion des Aluminium-Magnesium-Systems. Quantitative Analyse und numerische Modellierung

    Energy Technology Data Exchange (ETDEWEB)

    Seperant, Florian

    2012-03-21

    Aluminum coatings are a promising approach to protect magnesium alloys against corrosion and thereby making them accessible to a variety of technical applications. Thermal treatment enhances the adhesion of the aluminium coating on magnesium by interdiffusion. For a deeper understanding of the diffusion process at the interface, a quantitative description of the Al-Mg system is necessary. On the basis of diffusion experiments with infinite reservoirs of aluminum and magnesium, the interdiffusion coefficients of the intermetallic phases of the Al-Mg-system are calculated with the Sauer-Freise method for the first time. To solve contradictions in the literature concerning the intrinsic diffusion coefficients, the possibility of a bifurcation of the Kirkendall plane is considered. Furthermore, a physico-chemical description of interdiffusion is provided to interpret the observed phase transitions. The developed numerical model is based on a temporally varied discretization of the space coordinate. It exhibits excellent quantitative agreement with the experimentally measured concentration profile. This confirms the validity of the obtained diffusion coefficients. Moreover, the Kirkendall shift in the Al-Mg system is simulated for the first time. Systems with thin aluminum coatings on magnesium also exhibit a good correlation between simulated and experimental concentration profiles. Thus, the diffusion coefficients are also valid for Al-coated systems. Hence, it is possible to derive parameters for a thermal treatment by simulation, resulting in an optimized modification of the magnesium surface for technical applications.

  1. Numerical analyses of turbulence structure in rectangular ducts with rough and smooth walls. Applicability of simple analysis method using algebraic Reynolds stress model

    International Nuclear Information System (INIS)

    A numerical analysis has been performed for fully developed turbulent flow in a rectangular duct with smooth and rough walls by using algebraic Reynolds stress model. The wall functions and the universal law of the wall, which are used as the boundary conditions of turbulent energy and dissipation, apply in the present analysis instead of taking shape of roughness element into account. Therefore, the roughness enters through the log law relating the velocity at the first grid point away from the wall with the friction velocity. Two kinds of turbulent flows are examined, i.e., one is the turbulent flow in a rectangular duct with two roughened facing walls and the other is that flow in a rectangular duct with longitudinal ridges located lower and upper walls. These two kinds of calculated results are compared with experimental data each other. As for the comparison of rectangular duct with two roughened facing walls, the present calculated results show less distortion of streamwise velocity than the experimental data. This discrepancy may be attributable to assumption of the uniform roughness wall in calculation and separated flow observed in the experiment. On the other hand, calculated results of rectangular duct with ridges show a reasonable agreement in the streamwise velocity and the distributions of the Reynolds stresses. These examinations suggest the validity of the present method using the wall functions. (author)

  2. Experimental and numerical analyses on a plate heat exchanger with phase change for waste heat recovery at off-design conditions

    Science.gov (United States)

    Cipollone, Roberto; Bianchi, Giuseppe; Di Battista, Davide; Fatigati, Fabio

    2015-11-01

    This paper analyzes the performances of an evaporator for small scale waste heat recovery applications based on bottoming Organic Rankine Cycles with net output power in the range 2-5 kW. The heat recovery steam generator is a plate heat exchanger with oil as hot stream and an organic fluid on the cold side. An experimental characterization of the heat exchanger was carried out at different operating points measuring temperatures, pressures and flow rates on both sides. The measurement data further allowed to validate a numerical model of the evaporator whereas heat transfer coefficients were evaluated comparing several literature correlations, especially for the phase-change of the organic fluid. With reference to a waste heat recovery application in industrial compressed air systems, multiple off-design conditions were simulated considering the effects of oil mass flow rate and temperature on the superheating of the organic fluid, a key parameter to ensure a proper operation of the expansion machine, thus of the energy recovery process.

  3. Numerical study on the effects of aspect ratio and orientation of an urban street canyon on outdoor thermal comfort in hot and dry climate

    Energy Technology Data Exchange (ETDEWEB)

    Ali-Toudert, Fazia; Mayer, Helmut [Meteorological Institute, University of Freiburg,Werderring 10, D-79085 Freiburg (Germany)

    2006-02-01

    This paper discusses the contribution of street design, i.e. aspect ratio (or height-to-width ratio, H/W) and solar orientation, towards the development of a comfortable micro climate at street level for pedestrians. The investigation is carried out by using the three-dimensional numerical model ENVI-met, which simulates the microclimatic changes within urban environments in a high spatial and temporal resolution. Model calculations are run for a typical summer day in Ghardaia, Algeria (32.40{sup o}N, 3.80{sup o}E, 469ma.s.l.), a region characterized by a hot and dry climate. Symmetrical urban canyons, with various height-to-width ratios (i.e. H/W=0.5, 1, 2 and 4) and different solar orientations (i.e. E-W, N-S, NE-SW and NW-SE), have been studied. Special emphasis is placed on a human bio-meteorological assessment of these microclimates by using the physiologically equivalent temperature (PET). The results show contrasting patterns of thermal comfort between shallow and deep urban streets as well as between the various orientations studied. A comparison of all case studies reveals that the time and period of day during which extreme heat stress occurs, as well as the spatial distribution of PETs at street level, depend strongly on aspect ratio and street orientation. This is crucial since it will directly influence the design choices in relation to street usage, e.g. streets planned exclusively for pedestrian use or including motor traffic, and also the time of frequentation of urban spaces. Both investigated urban factors can mitigate extreme heat stress if appropriately combined. The solar access indoors has been briefly discussed as an additional criterion in designing the street by including winter needs for solar energy. (author)

  4. Investigating the sensitivity of numerical model simulations of the modern state of the Greenland ice-sheet and its future response to climate change

    Directory of Open Access Journals (Sweden)

    E. J. Stone

    2010-09-01

    Full Text Available Ice thickness and bedrock topography are essential boundary conditions for numerical modelling of the evolution of the Greenland ice-sheet (GrIS. The datasets currently in use by the majority of GrIS modelling studies are over two decades old and based on data collected from the 1970s and 80s. We use a newer, high-resolution Digital Elevation Model of the GrIS and new temperature and precipitation forcings to drive the Glimmer ice-sheet model offline under steady state, present day climatic conditions. Comparisons are made of ice-sheet geometry between these new datasets and older ones used in the EISMINT-3 exercise. We find that changing to the newer bedrock and ice thickness makes the greatest difference to Greenland ice volume and ice surface extent. When all boundary conditions and forcings are simultaneously changed to the newer datasets the ice-sheet is 33% larger in volume compared with observation and 17% larger than that modelled by EISMINT-3.

    We performed a tuning exercise to improve the modelled present day ice-sheet. Several solutions were chosen in order to represent improvement in different aspects of the GrIS geometry: ice thickness, ice volume and ice surface extent. We applied these new parameter sets for Glimmer to several future climate scenarios where atmospheric CO2 concentration was elevated to 400, 560 and 1120 ppmv (compared with 280 ppmv in the control using a fully coupled General Circulation Model. Collapse of the ice-sheet was found to occur between 400 and 560 ppmv, a threshold substantially lower than previously modelled using the standard EISMINT-3 setup. This work highlights the need to assess carefully boundary conditions and forcings required by ice-sheet models, particularly in terms of the abstractions required for large-scale ice-sheet models, and the implications that these can have on predictions of ice-sheet geometry under past and future climate scenarios.

  5. Global sensitivity analysis of thermo-mechanical models in numerical weld modelling; Analyse de sensibilite globale de modeles thermomecaniques de simulation numerique du soudage

    Energy Technology Data Exchange (ETDEWEB)

    Petelet, M

    2007-10-15

    Current approach of most welding modellers is to content themselves with available material data, and to chose a mechanical model that seems to be appropriate. Among inputs, those controlling the material properties are one of the key problems of welding simulation: material data are never characterized over a sufficiently wide temperature range {exclamation_point} This way to proceed neglect the influence of the uncertainty of input data on the result given by the computer code. In this case, how to assess the credibility of prediction? This thesis represents a step in the direction of implementing an innovative approach in welding simulation in order to bring answers to this question, with an illustration on some concretes welding cases. The global sensitivity analysis is chosen to determine which material properties are the most sensitive in a numerical welding simulation and in which range of temperature. Using this methodology require some developments to sample and explore the input space covering welding of different steel materials. Finally, input data have been divided in two groups according to their influence on the output of the model (residual stress or distortion). In this work, complete methodology of the global sensitivity analysis has been successfully applied to welding simulation and lead to reduce the input space to the only important variables. Sensitivity analysis has provided answers to what can be considered as one of the probable frequently asked questions regarding welding simulation: for a given material which properties must be measured with a good accuracy and which ones can be simply extrapolated or taken from a similar material? (author)

  6. Climate Physics

    Science.gov (United States)

    Space, William

    2007-01-01

    Numerous connections exist between climate science and topics normally covered in physics and physical science courses. For instance, lessons on heat and light can be used to introduce basic climate science, and the study of electric circuits provides a context for studying the relationship between electricity consumption and carbon pollution. To…

  7. Numerical Simulation Study on the Impacts of Tropospheric O3 and CO2 Concentration Changes on Winter Wheat. Part Ⅱ:Simulation Results and Analyses

    Institute of Scientific and Technical Information of China (English)

    ZHENG Changling; WANG Chunyi

    2006-01-01

    With the rapid development of industrialization and urbanization, the enrichment of tropospheric ozone and carbon dioxide concentration at striking rates has caused effects on biosphere, especially on crops. It is generally accepted that the increase of CO2 concentration will have obverse effects on plant productivity while ozone is reported as the air pollutant most damaging to agricultural crops and other plants. The Model of Carbon and Nitrogen Biogeochemistry in Agroecosystems (DNDC) was adapted to evaluate simultaneously impacts of climate change on winter wheat.Growth development and yield formation of winter wheat under different Os and CO2 concentration conditions are simulated with the improved DNDC model whose structure has been described in another paper. Through adjusting the DNDC model applicability, winter wheat growth and development in Gucheng Station were simulated well in 1993 and 1999, which is in favor of modifying the model further. The model was validated against experiment observation, including development stage data, leaf area index, each organ biomass, and total aboveground biomass. Sensitivity tests demonstrated that the simulated results in development stage and biomass were sensitive to temperature change. The main conclusions of the paper are the following: 1) The growth and yield of winter wheat under CO2 concentration of 500 ppmv, 700 ppmv and the current ozone concentration are simulated respectively by the model. The results are well fitted with the observed data of OTCs experiments. The results show that increase of CO2 concentration may improve the growth of winter wheat and elevate the yield. 2) The growth and yield of winter wheat under O3 concentration of 50 ppbv, 100 ppbv, 200 ppbv and the based concentration CO2 are simulated respectively by the model. The simulated curves of stem, leaf, and spike organs growth as well as leaf area index are well accounted with the observed data. The results reveal that ozone has negative

  8. Response of ice cover on shallow lakes of the North Slope of Alaska to contemporary climate conditions (1950–2011: radar remote sensing and numerical modeling data analysis

    Directory of Open Access Journals (Sweden)

    C. M. Surdu

    2013-07-01

    Full Text Available Air temperature and winter precipitation changes over the last five decades have impacted the timing, duration, and thickness of the ice cover on Arctic lakes as shown by recent studies. In the case of shallow tundra lakes, many of which are less than 3 m deep, warmer climate conditions could result in thinner ice covers and consequently, to a smaller fraction of lakes freezing to their bed in winter. However, these changes have not yet been comprehensively documented. The analysis of a 20 yr time series of ERS-1/2 synthetic aperture radar (SAR data and a numerical lake ice model were employed to determine the response of ice cover (thickness, freezing to the bed, and phenology on shallow lakes of the North Slope of Alaska (NSA to climate conditions over the last six decades. Analysis of available SAR data from 1991–2011, from a sub-region of the NSA near Barrow, shows a reduction in the fraction of lakes that freeze to the bed in late winter. This finding is in good agreement with the decrease in ice thickness simulated with the Canadian Lake Ice Model (CLIMo, a lower fraction of lakes frozen to the bed corresponding to a thinner ice cover. Observed changes of the ice cover show a trend toward increasing floating ice fractions from 1991 to 2011, with the greatest change occurring in April, when the grounded ice fraction declined by 22% (α = 0.01. Model results indicate a trend toward thinner ice covers by 18–22 cm (no-snow and 53% snow depth scenarios, α = 0.01 during the 1991–2011 period and by 21–38 cm (α = 0.001 from 1950–2011. The longer trend analysis (1950–2011 also shows a decrease in the ice cover duration by ∼24 days consequent to later freeze-up dates by 5.9 days (α = 0.1 and earlier break-up dates by 17.7–18.6 days (α = 0.001.

  9. Climate change

    NARCIS (Netherlands)

    Marchal, V.; Dellink, R.; Vuuren, D.P. van; Clapp, C.; Chateau, J.; Magné, B.; Lanzi, E.; Vliet, J. van

    2012-01-01

    This chapter analyses the policy implications of the climate change challenge. Are current emission reduction pledges made in Copenhagen/Cancun enough to stabilise the climate and limit global average temperature increase to 2 oC? If not, what will the consequences be? What alternative growth pathwa

  10. Hydrogeologic influence on changes in snowmelt runoff with climate warming: Numerical experiments on a mid-elevation catchment in the Sierra Nevada, USA

    Science.gov (United States)

    Jepsen, S. M.; Harmon, T. C.; Meadows, M. W.; Hunsaker, C. T.

    2016-02-01

    The role of hydrogeology in mediating long-term changes in mountain streamflow, resulting from reduced snowfall in a potentially warmer climate, is currently not well understood. We explore this by simulating changes in stream discharge and evapotranspiration from a mid-elevation, 1-km2 catchment in the southern Sierra Nevada of California (USA) in response to reduced snowfall under warmer conditions, for a plausible range in subsurface hydrologic properties. Simulations are performed using a numerical watershed model, the Penn State Integrated Hydrologic Model (PIHM), constrained by observations from a meteorological station, stream gauge, and eddy covariance tower. We predict that the fraction of precipitation occurring as snowfall would decrease from approximately 47% at current conditions to 25%, 12%, and 5% for air temperature changes of +2, +4, and +6 °C. For each of these warming scenarios, changes in mean annual discharge and evapotranspiration simulated by the different plausible soil models show large ranges relative to averages, with coefficients of variation ranging from -3 to 3 depending on warming scenario. With warming and reduced snowfall, substrates with greater storage capacity show less soil moisture limitation on evapotranspiration during the late spring and summer, resulting in greater reductions in annual stream discharge. These findings indicate that the hydrologic response of mountain catchments to atmospheric warming and reduced snowfall may substantially vary across elevations with differing soil and regolith properties, a relationship not typically accounted for in approaches relying on space-for-time substitution. An additional implication of our results is that model simulations of annual stream discharge in response to snowfall-to-rainfall transitions may be relatively uncertain for study areas where subsurface properties are not well constrained.

  11. Late-Holocene climate variability and ecosystem responses in Alaska inferred from high-resolution multiproxy sediment analyses at Grizzly Lake

    Science.gov (United States)

    Tinner, Willy; Beer, Ruth; Bigler, Christian; Clegg, Benjamin F.; Jones, Richard T.; Kaltenrieder, Petra; van Raden, Ulrike J.; Gilli, Adrian; Hu, Feng Sheng

    2015-10-01

    The late-Holocene shift from Picea glauca (white spruce) to Picea mariana (black spruce) forests marked the establishment of modern boreal forests in Alaska. To understand the patterns and drivers of this vegetational change and the associated late-Holocene environmental dynamics, we analyzed radiocarbon-dated sediments from Grizzly Lake for chironomids, diatoms, pollen, macrofossils, charcoal, element composition, particle size, and magnetic properties for the period 4100-1800 cal BP. Chironomid assemblages reveal two episodes of decreased July temperature, at ca. 3300-3150 (ca -1 °C) and 2900-2550 cal BP (ca -2 °C). These episodes coincided with climate change elsewhere in the Northern Hemisphere, atmospheric reorganization, and low solar activity. Diatom-inferred lake levels dropped by ca. 5 m at 3200 cal BP, suggesting dry conditions during the period 3200-1800 cal BP. P. glauca declined and P. mariana expanded at ca. 3200 cal BP; this vegetational change was linked to diatom-inferred low lake levels and thus decreased moisture availability. Forest cover declined at 3300-3100, 2800-2500 and 2300-2100 cal BP and soil erosion as inferred from increased values of Al, K, Si, Ti, and Ca intensified, when solar irradiance was low. Plant taxa adapted to disturbance and cold climate (e.g. Alnus viridis, shrub Betula, Epilobium) expanded during these periods of reduced forest cover. This open vegetation type was associated with high fire activity that peaked at 2800 cal BP, when climatic conditions were particularly cold and dry. Forest recovery lagged behind subsequent climate warming (≤+3 °C) by ca. 75-225 years. Our multiproxy data set suggests that P. glauca was dominant under warm-moist climatic conditions, whereas P. mariana prevailed under cold-dry and warm-dry conditions. This pattern implies that climatic warming, as anticipated for this century, may promote P. glauca expansions, if moisture availability will be sufficiently high, while P. mariana may

  12. An open GIS framework for recording and analysing post-occupancy changes in residential buildings - a climate-related case study

    Energy Technology Data Exchange (ETDEWEB)

    Etzion, Y.; Portnov, B.A.; Erell, E.; Meir, I.; Pearlmutter, D. [Ben-Gurion Univ. of the Negev, Unit of Desert Architecture and Urban Planning, Sede-Boker (Israel)

    2001-12-01

    A GIS-based method is proposed, which simplifies recording and analysis of post-occupancy changes in residential buildings. Each modification is considered as a unique record in a database, and has a string assigned to it in a multi-parametric matrix. Its position in the matrix is determined by functional relationships with other housing modifications, orientation, adjacent inner and outer spaces, building materials and physical size. The method was tested in three residential neighbourhoods in two towns in the Negev desert of Israel, with the intention of (a) highlighting modifications related to the climatic performance of buildings and (b) developing a set of recommendations aimed at improving the design of new residential buildings. In the buildings surveyed, post-occupancy changes were made primarily in ground-level apartments and in outdoor private spaces. Building modifications appear to vary in different functional areas of the dwelling units, suggesting a connection between dweller preferences and climatic response. (Author)

  13. Dutch climate and energy policy. Analysis of policy reviews 1989-2012; Het Nederlandse Klimaat- en Energiebeleid. Analyse van beleidsevaluaties 1989-2012

    Energy Technology Data Exchange (ETDEWEB)

    Faber, J.; Blom, M.J.; De Bruyn, S.M.; Nelissen, D.; Aarnink, S.J.; De Buck, A.; Bennink, D. [CE Delft, Delft (Netherlands); Oosterhuis, F.H.; Kuik, O.J. [Instituut voor Milieuvraagstukken IVM, Vrije Universiteit VU, Amsterdam (Netherlands)

    2012-11-15

    The Dutch government has had climate policy in place since 1989. Since 1999 that policy has been intensified with a view to meeting Kyoto commitments for the period 2008-2012. The Dutch Parliament requested a review of the costs and effects of the measures implemented in the context of Dutch climate and energy policy, based on the available review studies, with led to the commissioning of the present report [Dutch] De Nederlandse overheid voert sinds 1989 klimaatbeleid. Vanaf 1999 is het beleid geïntensiveerd met het oog op het halen van de Kyoto-doelstelling in de periode 2008-2012. De Tweede Kamer wil een overzicht hebben van de kosten en effecten van beleidsinstrumenten van het Nederlandse klimaat- en energiebeleid, op basis van bestaande evaluatiestudies en heeft daarom deze studie laten uitvoeren.

  14. Biogas production in Oestfold. Analysis of climate utility and economy in a value chain perspective; Biogassproduksjon i Oestfold. Analyse av klimanytte og oekonomi i et verdikjedeperspektiv

    Energy Technology Data Exchange (ETDEWEB)

    Arnoey, Silje; Moeller, Hanne; Modahl, Ingunn Saur; Soerby, Ivar; Hanssen, Ole Joergen

    2013-03-01

    Waste management is an important issue. How we choose to deal with food waste that occurs, affects climate through emissions from all phases of waste management. One way of handling waste is to produce biogas from it. General results of the project 'the continuation of biogas model' has shown that the use of food waste as a substrate for biogas production in interaction with manure and great climate benefit. In order to assess the development of biogas production specifically for Oestfold, the general model was used for analysis with specific Oestfold data.The project's goal is that through the development of Oestfoldforskning's present climate and economic models will be carried out analyzes where these models will be tested with specific data of hypothetical case.These analyzes will form the basis for a strategic decision on the location and design of biogas plants in Oestfold. It should be noted that this report only will present greenhouse gas emissions, which represent an environmental indicator, and that the result of greenhouse gas emissions may not be directly transferable to other environmental indicators. Shortened version. (eb)

  15. Effects of technological progress and climate protection on electric power generation. Analyses using a General Equilibrium Model; Auswikungen des technologischen Fortschritts und des Klimaschutzes auf die Stromerzeugung. Analysen mit einem Allgemeinen Gleichgewichtsmodell

    Energy Technology Data Exchange (ETDEWEB)

    Zuern, Marcel

    2010-07-01

    The target of this thesis is the analysis of the connection between technological change and the development of global GHG with a quantitative analytic framework. Due to the special importance of the electricity generation sector for the mitigation of CO{sub 2} special attention is paid to this sector. The analysis of technological progress, particularly in the power generation sector on a global level, asks for substantial requirements of the analytic framework. The great number of actors and the interplay of interdependent factors make an analytical solution to the problem impossible. Therefore, a quantitative numerical model is necessary in order to analyse technological change on a global level. For the analysis of innovation and technological progress the sectoral, regional and chronological dimensions have to be considered explicitly: The analysis should take all economic areas into account because innovations are not restricted to a certain industrial sector or certain area of the economy but involve the whole economy. Concerning the geographical dimension innovations are not bound to a single country but spread out over national borders. Adjustments to technological development take time to unfold, and therefore an analytical framework should cover a long-term horizon. The same requirements apply to the regional, geographical and chronological dimensions when analysing measures to reduce GHG. The general equilibrium model used in this work (CGE - Computable General Equilibrium) fulfils all of the requirements listed above. Since the GHG problem is a global one, its analysis demands of model that is appropriate for this level. The structure of GHG models and the use of economic data on the global level allow for the correct methodology therefore. Since adjustments to measures of climate protection as well as innovations and technological change need time, a dynamic general equilibrium model with a long-term time horizon is used. Further advantages of CGE

  16. Study and Application of Parallel I/O Technology in Numerical Climate Model%并行I/O技术在气候数值模式中的应用研究

    Institute of Scientific and Technical Information of China (English)

    魏敏; 徐金秀; 王在志

    2014-01-01

    在气候变化数值模拟工作中,气候数值模式运行效率主要受到计算效率和I/O效率的共同影响。目前,模式计算部分已经基本实现并行,计算效率显著提升。随着气候数值模式时空分辨率的提高,对I/O效率的需求也不断增加,数据并行I/O技术已经成为提高模式整体运行效率的有效方法之一。文中深入分析了BCC AGCM模式串行I/O算法及NetC-DF数据结构特点,采用基于MPI-IO的高层I/O库对模式I/O算法进行并行优化,优化后可支持多类气象要素并行输出,输出效率明显提升。为我国应对气候变化数值模式的运行效率优化工作,进行了有益的技术探索和积累。%Computational efficiency and I/O efficiency affect the efficiency of numerical climate model together in climate change numeri-cal simulation. Model computation section has been parallelized and the efficiency significantly increased. With the improvement of spatial and temporal resolution of numerical climate model,the demand of data access efficiency is also increased dramatically. The parallel I/O technology has become an effective method to improve the efficiency of numerical climate model. In this paper,analyze the serial I/O al-gorithm of BCC AGCM mode and the data structure features of NetCDF. Use high level I/O library based on MPI-IO to optimize model data interface,the new system can support parallel output of multiple meteorological elements and data output efficiency has improved sig-nificantly. Carry out useful technical exploration and accumulation for the efficiency optimization of numerical climate model.

  17. Qualification des logiciels numériques. Application à un logiciel d'analyse de la combustion dans les moteurs à allumage commandé Qualification of Numerical Software. Application to a Software for Analysing Combustion in Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Vignes J.

    2006-11-01

    Full Text Available La simulation numérique est actuellement très utilisée pour étudier les systèmes physiques. Elle nécessite un programme de calcul scientifique constitué d'un modèle mathématique représentatif du problème étudié et des méthodes numériques de résolution associées. Elle fournit des résultats numériques censés représenter le phénomène physique. Pour pouvoir valider la simulation, il est absolument indispensable, d'une part, d'estimer la propagation des erreurs d'arrondi due à l'arithmétique approchée des ordinateurs et, d'autre part, d'évaluer l'influence des erreurs de données sur les résultats fournis. Nous présentons, dans cet article, le logiciel CADNA qui permet de valider les logiciels numériques. Nous l'appliquons à un logiciel de simulation d'analyse de la combustion dans les moteurs à allumage commandé et en montrons son efficacité. For analyzing physical phenomena, numerical simulation is used more and more frequently. Starting with a mathematical model describing the phenomenon being analyzed, this simulation consists in creating a scientific computing program expressing this model by implementing the numerical methods required for solving it. Simulation is considered to be valid when the results its provides are in agreement with the results issuing from experimenting with the phenomenon. However, to conclude in the possible validity of the simulation, the numerical results provided by the computer must be previously validated. Yet, these results contain a computing error resulting from the propagation of round-off errors caused by the floating-point arithmetic used by the computer. They also contain an error coming from the uncertainties concerning the data of the problem. Hence it is first indispensable to assess the influence of these errors. This article is made up of two parts. The first part concerns the validation of numerical software results. After making a brief review of the floating

  18. Statistical analyses for the purpose of an early detection of global and regional climate change due to the anthropogenic greenhouse effect; Statistische Analysen zur Frueherkennung globaler und regionaler Klimaaenderungen aufgrund des anthropogenen Treibhauseffektes

    Energy Technology Data Exchange (ETDEWEB)

    Grieser, J.; Staeger, T.; Schoenwiese, C.D.

    2000-03-01

    The report answers the question where, why and how different climate variables have changed within the last 100 years. The analyzed variables are observed time series of temperature (mean, maximum, minimum), precipitation, air pressure, and water vapour pressure in a monthly resolution. The time series are given as station data and grid box data as well. Two kinds of time-series analysis are performed. The first is applied to find significant changes concerning mean and variance of the time series. Thereby also changes in the annual cycle and frequency of extreme events arise. The second approach is used to detect significant spatio-temporal patterns in the variations of climate variables, which are most likely driven by known natural and anthropogenic climate forcings. Furtheron, an estimation of climate noise allows to indicate regions where certain climate variables have changed significantly due to the enhanced anthropogenic greenhouse effect. (orig.) [German] Der Bericht gibt Antwort auf die Frage, wo sich welche Klimavariable wie und warum veraendert hat. Ausgangspunkt der Analyse sind huntertjaehrige Zeitreihen der Temperatur (Mittel, Maximum, Minimum), des Niederschlags, Luftdrucks und Wasserdampfpartialdrucks in monatlicher Aufloesung. Es wurden sowohl Stationsdaten als auch Gitterpunktdaten verwendet. Mit Hilfe der strukturorientierten Zeitreihenzerlegung wurden signifikankte Aenderungen im Mittel und in der Varianz der Zeitreihen gefunden. Diese betreffen auch Aenderungen im Jahresgang und in der Haeufigkeit extremer Ereignisse. Die ursachenorientierte Zeitreihenzerlegung selektiert signifikante raumzeitliche Variationen der Klimavariablen, die natuerlichen bzw. anthropogenen Klimaantrieben zugeordnet werden koennen. Eine Abschaetzung des Klimarauschens erlaubt darueber hinaus anzugeben, wo und wie signifikant der anthropogene Treibhauseffekt welche Klimavariablen veraendert hat. (orig.)

  19. Bridging long proxy data time series and instrumental observation in the Virtual Institute of Integrated Climate and Landscape Evolution Analyses - ICLEA

    Science.gov (United States)

    Schwab, Markus J.; Brauer, Achim; Błaszkiewicz, Mirosław; Raab, Thomas; Wilmking, Martin

    2015-04-01

    Understanding causes and effects of present-day climate change on landscapes and the human habitat faces two main challenges, (i) too short time series of instrumental observation that do not cover the full range of variability since mechanisms of climate change and landscape evolution work on different time scales, which often not susceptible to human perception, and, (ii) distinct regional differences due to the location with respect to oceanic/continental climatic influences, the geological underground, and the history and intensity of anthropogenic land-use. Both challenges are central for the ICLEA research strategy and demand a high degree of interdisciplinary. In particular, the need to link observations and measurements of ongoing changes with information from the past taken from natural archives requires joint work of scientists with very different time perspectives. On the one hand, scientists that work at geological time scales of thousands and more years and, on the other hand, those observing and investigating recent processes at short time scales. The GFZ, Greifswald University and the Brandenburg University of Technology together with their partner the Polish Academy of Sciences strive for focusing their research capacities and expertise in ICLEA. ICLEA offers young researchers an interdisciplinary and structured education and promote their early independence through coaching and mentoring. Postdoctoral rotation positions at the ICLEA partner institutions ensure mobility of young researchers and promote dissemination of information and expertise between disciplines. Training, Research and Analytical workshops between research partners of the ICLEA virtual institute are another important measure to qualify young researchers. The long-term mission of the Virtual Institute is to provide a substantiated data basis for sustained environmental maintenance based on a profound process understanding at all relevant time scales. Aim is to explore processes of

  20. Analyses of surface and groundwater flow characteristics of the Ljubljana moor and water resources vulnerability to climate and land use change and groundwater overdraft

    Science.gov (United States)

    Globevnik, Lidija; Bracic Zeleznik, Branka

    2016-04-01

    One of the biggest water resource of Slovenian capital is groundwater of Ljubljana moor (Ljubljansko barje) aquifer. Quantity and quality of groundwater in Ljubljana moor aquifer directly depend on precipitation, surface water and riparian ecosystems of the Moor and indirectly by groundwater recharge from higher-lying mountainous karstic areas of forests and grasslands. Maintaining high groundwater level of the Ljubljana moor not only sustain stable water balance of aquifer, but also its riparian and wetland character. It also inhibit larger subsidence of the terrain. The paper addresses the vulnerability of the Ljubljana moor water resources to climate and land use change and due to groundwater overdraft. The results should help in selecting suitable mitigation measures and management of the Ljubljana moor area. We analyze surface and groundwater flow characteristics of water recharge area of one water work on the Ljubljana moor (Brest) from the point of view of climate change, changes in land use and water pumping practices. The I\\vska River, a tributary to the Ljubljanica River, recharges the area in the gravel bar, which lies just below the hills. We use existing data of meteorological, hydrological and hydrogeological monitoring and simulate rainfall-runoff processes. We use a conceptual semi-distributed rainfall-runoff model HBV-Light and simulate hydrological characteristics of the Ljubljana Moor (groundwater level fluctuations and recharge, surface - groundwater interchange) with two hydrodynamic models, DHI MIKE FLOOD (surface flow, 2D simulation) and DHI MIKE SHE (groundwater flow). For a calibration of runoff model HBV Light and MIKE SHE we use measured daily discharge data of the river I\\vska (1970-2010) and groundwater level data along the river (2010-2013) respectively. In groundwater modelling, we include the data of water pumping. Daily precipitation and temperature for period 2020 - 2050 are from ESAMBLE project for two GCM climate scenarios. We

  1. Climate and anthropogenic factors influencing an estuarine ecosystem from NW Iberia: new high resolution multiproxy analyses from San Simón Bay (Ría de Vigo)

    Science.gov (United States)

    Muñoz Sobrino, Castor; García-Moreiras, Iria; Castro, Yoel; Martínez Carreño, Natalia; de Blas, Esther; Fernandez Rodríguez, Carlos; Judd, Alan; García-Gil, Soledad

    2014-06-01

    Two sedimentary sequences (coastal and subtidal) were studied in San Simón Bay (Ría de Vigo), situated on the Atlantic coast of NW Iberia. The coastal record is a shallowing upward sequence which evidences a locally-developed low marsh, situated below the current beach, and dated at the second half of the 4th century. During the following decades this low marsh was progressively replaced by an alder swamp which formed on it. This suggests an apparent stabilisation or slow-down of the relative sea-level (RSL), in this site, at the beginning of the Dark Ages (DA). The subtidal sequence studied reflects the main changes in the landscape, the hydrological conditions, climate and RSL affecting this part of NW Iberia during the last 1250 years. Evidence of changing dinocysts content in the sediment reveals that two centennial or decadal-scale episodes existed of shelf marine waters more intensely penetrating inside the bay: between the 15th-18th centuries and at ca 1800-1930 AD. Besides, we related different proxies with the occurrence of four main climatic stages, namely the previously described Dark Ages (DA, ca 350-750 AD), the Mediaeval Climatic Anomaly (MCA, ca 750-1100 AD) and the Little Ice Age (LIA. ca 1500-1930 AD); in addition we propose a regional MCA/LIA transition (ca 1100-1500 AD) that it has not been previously described. Our environmental characterization indicates a persistent North Atlantic Oscillation (NAO) negative mode domain in Ría de Vigo during the MCA, but this became weaker during the LIA and, probably, also during the earlier DA. NAO mode become more irregular during the MCA/LIA transition, generally persisting in dominant negative mode except for a phase of minor upwelling intensification, at ca 1150-1350 AD, which mainly affected the external parts of the ria. We postulate that an almost simultaneous phase (ca 1100-1350 AD) of stronger continental contribution in the sediments may be related to increasing storm intensities, probably linked

  2. Development of regional future climate change scenarios in South America using the Eta CPTEC/HadCM3 climate change projections: climatology and regional analyses for the Amazon, Sao Francisco and the Parana River basins

    Energy Technology Data Exchange (ETDEWEB)

    Marengo, Jose A.; Chou, Sin Chan; Alves, Lincoln M.; Pesquero, Jose F.; Soares, Wagner R.; Santos, Daniel C.; Lyra, Andre A.; Sueiro, Gustavo; Chagas, Diego J.; Gomes, Jorge L.; Bustamante, Josiane F.; Tavares, Priscila [National Institute for Space Research (INPE) Cachoeira Paulista, Sao Paulo (Brazil); Kay, Gillian; Betts, Richard [UK Met Office Hadley Centre, Exeter, Devon (United Kingdom)

    2012-05-15

    The objective of this study is to assess the climate projections over South America using the Eta-CPTEC regional model driven by four members of an ensemble of the Met Office Hadley Centre Global Coupled climate model HadCM3. The global model ensemble was run over the twenty-first century according to the SRES A1B emissions scenario, but with each member having a different climate sensitivity. The four members selected to drive the Eta-CPTEC model span the sensitivity range in the global model ensemble. The Eta-CPTEC model nested in these lateral boundary conditions was configured with a 40-km grid size and was run over 1961-1990 to represent baseline climate, and 2011-2100 to simulate possible future changes. Results presented here focus on austral summer and winter climate of 2011-2040, 2041-2070 and 2071-2100 periods, for South America and for three major river basins in Brazil. Projections of changes in upper and low-level circulation and the mean sea level pressure (SLP) fields simulate a pattern of weakening of the tropical circulation and strengthening of the subtropical circulation, marked by intensification at the surface of the Chaco Low and the subtropical highs. Strong warming (4-6 C) of continental South America increases the temperature gradient between continental South America and the South Atlantic. This leads to stronger SLP gradients between continent and oceans, and to changes in moisture transport and rainfall. Large rainfall reductions are simulated in Amazonia and Northeast Brazil (reaching up to 40%), and rainfall increases around the northern coast of Peru and Ecuador and in southeastern South America, reaching up to 30% in northern Argentina. All changes are more intense after 2040. The Precipitation-Evaporation (P-E) difference in the A1B downscaled scenario suggest water deficits and river runoff reductions in the eastern Amazon and Sao Francisco Basin, making these regions susceptible to drier conditions and droughts in the future

  3. Climate Change

    OpenAIRE

    The IJOEM

    2010-01-01

    This chapter analyses the policy implications of the climate change challenge. Are current emission reduction pledges made in Copenhagen/Cancun enough to stabilise the climate and limit global average temperature increase to 2 oC? If not, what will the consequences be? What alternative growth pathways could stabilise the global average atmospheric concentration of greenhouse gases (GHG) at 450 ppm, the level which has a 50% chance of keeping the temperature rise to 2 oC? What policies are nee...

  4. Analysing Italian Regional Patterns in Green Economy and Climate Change. Can Italy Leverage on Europe 2020 Strategy to Face Sustainable Growth Challenges ?

    Directory of Open Access Journals (Sweden)

    Francesco BONSINETTO

    2013-12-01

    Full Text Available European cities and regions are facing the crucial challenge of greening their economy towards more sustainable patterns. Politicians and policy-makers should promote new policies for sustainable growth including renewables, greenhouse gas emissions, energy efficiency and biodiversity. All of these aspects can be considered as a boost for local and regional economy. In this regard, European countries and regions can benefit from the Europe 2020 Strategy which is defined as Europe’s blueprint for a smart, sustainable and inclusive future, providing a ten year roadmap for growth and jobs. EU2020S was designed as a European exit strategy from the global economic and financial crisis in view of new European economic governance. This study discusses the above issues regarding Italy and intends to provide some answers on the perspectives of the new EU2020S. It draws from a research project supported by ESPON, the S.I.E.S.T.A. Project, focused on the territorial dimension of the EU2020S. Therefore, this paper aims at analyzing Italian regional patterns on climate change, green economy and energy within the context of EU2020S and at providing policy recommendations for better achieving the goals of the Strategy.

  5. Development and application of a numerical simulation system to evaluate the impact of anthropogenic heat fluxes on urban boundary layer climate

    OpenAIRE

    Krpo, Andrea

    2009-01-01

    Increasing economic development, and growing population, generated during the last decades a very important growth of cities. Urban regions include nowadays more than half of the global population and, by 2030, this proportion is forecasted to increase to three quarters. A consequent more and more extensive use of natural resources, together with increasing anthropogenic activities such as emissions from traffic and factories, or heating from air-conditioning facilities, modify local climate ...

  6. Reconstructing the response of C3 and C4 plants to decadal-scale climate change during the late Pleistocene in southern Illinois using isotopic analyses of calcified rootlets

    Science.gov (United States)

    Wang, Hongfang; Greenberg, S.E.

    2007-01-01

    The ??13C and ??18O values of well-preserved carbonate rhizoliths (CRs) provide detailed insights into changes in the abundance of C3 and C4 plants in response to approximately decadal-scale changes in growing-season climate. We performed stable isotope analyses on 35-40 CRs sampled at 1-cm intervals from an 18-cm-thick paleosol formed in southern Illinois during Wisconsin interstadial 2. Minimum ??13C values show little variation with depth, whereas maximum values vary dramatically, and average values show noticeable variability; maximum ??18O values vary less than the minimum ??18O values. These findings indicate that a diverse and stable C3 flora with a limited number of C4 grass species prevailed during this interval, and suggest that the maximum growing-season temperatures were relatively stable, but minimum growing-season temperatures varied considerably. Two general patterns characterize the relationships between the ??13C and ??18O values obtained from the 1-cm samples. In some cases, low ??13C values correspond to low ??18O values and high ??13C values correspond to high ??18O values, suggesting that cooler growing-season temperatures favored C3 and warmer growing-season temperatures favored C4 plants. In other cases, low ??13C values correspond to high ??18O values, likely suggesting that wetter growing-season conditions were favorable to C3 plants. The high density of well-preserved CRs in this paleosol provides a unique opportunity to study detailed ecological responses to high-resolution variability in growing-season climate. ?? 2006 University of Washington.

  7. Etruscan numerals

    Directory of Open Access Journals (Sweden)

    Alemko Gluhak

    1978-12-01

    Full Text Available The origm of the Etruscan numerals was tried to be explained in many ways, considering the meanings given to numerals. In this article etymologies of the Etruscan numerals are given with regard to the order given by Wilkins, Pfiffif and Izbicki – u, zal, ci, śa, max, hu, sem, cezp, nur, śar.

  8. Numerical analysis

    CERN Document Server

    Khabaza, I M

    1960-01-01

    Numerical Analysis is an elementary introduction to numerical analysis, its applications, limitations, and pitfalls. Methods suitable for digital computers are emphasized, but some desk computations are also described. Topics covered range from the use of digital computers in numerical work to errors in computations using desk machines, finite difference methods, and numerical solution of ordinary differential equations. This book is comprised of eight chapters and begins with an overview of the importance of digital computers in numerical analysis, followed by a discussion on errors in comput

  9. Numerical modeling of the Snowmass Creek paleoglacier, Colorado, and climate in the Rocky Mountains during the Bull Lake glaciation (MIS 6)

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Leonard; Mitchell A. Plummer; Paul E. Carrara

    2014-04-01

    Well-preserved moraines from the penultimate, or Bull Lake, glaciation of Snowmass Creek Valley in the Elk Range of Colorado present an opportunity to examine the character of the high-altitude climate in the Rocky Mountains during Marine Oxygen Isotope Stage 6. This study employs a 2-D coupled mass/energy balance and flow model to assess the magnitudes of temperature and precipitation change that could have sustained the glacier in mass-balance equilibrium at its maximum extent during the Bull Lake glaciation. Variable substrate effects on glacier flow and ice thickness make the modeling somewhat more complex than in geologically simpler settings. Model results indicate that a temperature depression of about 6.7°C compared with the present (1971–2000 AD) would have been necessary to sustain the Snowmass Creek glacier in mass-balance equilibrium during the Bull Lake glaciation, assuming no change in precipitation amount or seasonality. A 50% increase or decrease from modern precipitation would have been coupled with 5.2°C and 9.1°C Bull Lake temperature depressions respectively. Uncertainty in these modeled temperature depressions is about 1°C.

  10. AMS analyses at ANSTO

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, E.M. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Physics Division

    1998-03-01

    The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with {sup 14}C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for {sup 14}C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent`s indigenous Aboriginal peoples. (author)

  11. Island shadow effects and the wave climate of the Western Tuamotu Archipelago (French Polynesia) inferred from altimetry and numerical model data.

    Science.gov (United States)

    Andréfouët, Serge; Ardhuin, Fabrice; Queffeulou, Pierre; Le Gendre, Romain

    2012-01-01

    To implement a numerical model of atoll lagoon circulation, we characterized first the significant wave height (Hs) regime of the Western Tuamotu Archipelago and the local attenuation due to the protection offered by large atolls in the south Tuamotu. Altimetry satellite data and a WAVEWATCH III two-way nested wave model at 5 km resolution from 2000 to 2010 were used. Correlation between altimetry and model was high (0.88) over the period. According to the wave model, the archipelago inner seas experienced attenuated Hs year-long with a yearly average Hs around 1.3m vs a minimum of 1.6m elsewhere. The island shadow effect is especially significant in the austral winter. In contrast with southern atolls, Western Tuamotu experienced only few days per year of Hs larger than 2.5m generated by very high Hs southern swell, transient western local storms, strong easterly winds, and during the passage of distant hurricanes. PMID:22795488

  12. Reliance, liance et alliance : opérationnalité des concepts dans l'analyse du climat socio-relationnel de groupes restreints d'apprentissage en ligne

    Directory of Open Access Journals (Sweden)

    Jean-Jacques Quintin

    2010-10-01

    Full Text Available La recherche que nous présentons ici se donne pour but de mesurer le lien entre le "climat socio-relationnel" d'un groupe restreint engagé dans un travail collaboratif en ligne et la qualité des travaux collectifs produits. La démarche méthodologique adoptée, basée sur une analyse des échanges asynchrones entre les membres d'un groupe, nous permet d'aboutir à un modèle opératoire qui fait état des composantes du "climat socio-relationnel" susceptibles d'expliquer les résultats d'apprentissage obtenus. Deux notions – dérivées du concept sociologique de reliance – seront mobilisées : la liance et l'alliance. La première rend compte de la qualité de la relation (la chaleur, l'intimité, les émotions… qui se crée entre les interlocuteurs au cours de leurs échanges asynchrones. La seconde traduit la manière dont les participants confortent leur contrat d'association en vue de la réalisation du travail commun, afin de répondre aux exigences pédagogiques fixées. Les résultats de cette recherche montrent que, dans notre situation d'étude, le modèle de la reliance explique une part substantielle de la qualité moyenne des produits de l'apprentissage collectif et possède une homogénéité interne non négligeable. Ces éléments concourent à étayer l'assise conceptuelle et le caractère opératoire du modèle présenté.The aim of the research we are presenting here is to measure the link between the "socio-relational climate" of a small group in a collaborative work environment and the quality of the collective work they provide. The methodological approach adopted, based on an analysis of the asynchronous exchanges between members of a group, allows us to find a procedure that takes stock of some components of "socio-relational climate" that could account for the results in terms of learning. Two notions – derivatives of the sociological concept "reliance" – will be called upon: "liance" and "alliance". The

  13. Numerical taxonomy

    OpenAIRE

    Inger, Robert F.

    2012-01-01

    For some strange reason the attitudes of taxonomists and systematists towards the phrase "numerical taxonomy" fall into two extreme positions. On the one hand are those who think numerical taxonomy provides the only means of reaching objective conclusions, that any other approach to taxonomy is sterile, subjective, and really not quite scientific. At the other extreme are those taxonomists who think numerical taxonomy has no place in their science, that it is unclean or is likely to be ...

  14. Numerical simulation of groundwater artificial recharge in a semiarid-climate basin of northwest Mexico, case study the Guadalupe Valley Aquifer, Baja California

    Science.gov (United States)

    Campos-Gaytan, J. R.; Herrera-Oliva, C. S.

    2013-05-01

    In this study was analyzed through a regional groundwater flow model the effects on groundwater levels caused by the application of different future groundwater management scenarios (2007-2025) at the Guadalupe Valley, in Baja California, Mexico. Among these studied alternatives are those scenarios designed in order to evaluate the possible effects generated for the groundwater artificial recharge in order to satisfy a future water demand with an extraction volume considered as sustainable. The State of Baja California has been subject to an increment of the agricultural, urban and industrials activities, implicating a growing water-demand. However, the State is characterized by its semiarid-climate with low surface water availability; therefore, has resulted in an extensive use of groundwater in local aquifer. Water level measurements indicate there has been a decline in water levels in the Guadalupe Valley for the past 30 years. The Guadalupe Valley aquifer represents one the major sources of water supply in Ensenada region. It supplies about 25% of the water distributed by the public water supplier at the city of Ensenada and in addition constitutes the main water resource for the local wine industries. Artificially recharging the groundwater system is one water resource option available to the study zone, in response to increasing water demand. The existing water supply system for the Guadalupe Valley and the city of Ensenada is limited since water use demand periods in 5 to 10 years or less will require the construction of additional facilities. To prepare for this short-term demand, one option available to water managers is to bring up to approximately 3.0 Mm3/year of treated water of the city of Ensenada into the valley during the low-demand winter months, artificially recharge the groundwater system, and withdraw the water to meet the summer demands. A 2- Dimensional groundwater flow was used to evaluate the effects of the groundwater artificial recharge

  15. 宁夏近百年来的气候变化及突变分析%Period and Jump Analyses of Climatic Variation in Ningxia in Recent Hundred Years

    Institute of Scientific and Technical Information of China (English)

    李艳春; 李艳芳

    2001-01-01

    Using Mann-Kendall jump test and moving t test, the periods andjump character of climatic variation in Ningxia in recent century are analysed based on the data of annual rainfall and temperature departure during recent hundred years in north of Ningxia and the data of temperature and precipitation obtained from 19 meterological stations of Ningxia since using apparatus. The results show that the climate in Ningxia during recent century can be divided into 5 main periods. Before 1930's, it was a dry and cold period; from 1930's to the middle 1950's, a warm and humid period; from the middle 1950's to the late 1960's, a cold and humid period; from the late 1960's to the middle 1980's, a cold and dry period, and from the middle 1980's to now, a warm and dry period. The annual mean temperature as well as autumn and winter temperature became jump in the middle 1980's. About 1960's, the annual precipitation became jump and in the middle and late 1970's, the autumn precipitation of Ningxia became jump.%以宁夏北部地区近百年来的年降水量、气温距平资料以及全区各季有仪器观测以来的温度降水资料为基础,利用Mann-Kendall突变检验法和滑动t检验法,分析了宁夏近百年来气候变化的阶段性和突变特点。结果表明:近百年来宁夏气候大概经历了五个主要阶段;80年代中期年平均气温及秋冬季平均气温发生突变;60年代左右年降水量发生突变;70年代中后期全区秋季降水量出现突变。

  16. Numerical Development

    Science.gov (United States)

    Siegler, Robert S.; Braithwaite, David W.

    2016-01-01

    In this review, we attempt to integrate two crucial aspects of numerical development: learning the magnitudes of individual numbers and learning arithmetic. Numerical magnitude development involves gaining increasingly precise knowledge of increasing ranges and types of numbers: from non-symbolic to small symbolic numbers, from smaller to larger…

  17. LHS (latin hypercubes) sampling of the material properties of steels for the analysis of the global sensitivity in welding numerical simulation; Echantillonnage LHS des proprietes materiau des aciers pour l analyse de sensibilite globale en simulation numerique du soudage

    Energy Technology Data Exchange (ETDEWEB)

    Petelet, Matthieu; Asserin, Olivier [CEA, DRT / LITEN / DTH / LTA, Bat 611, 91191 Gif sur Yvette Cedex (France); Iooss, Bertrand [CEA, DEN / CAD / DER / SESI / LCFR, Bat 212, 13108 St-Paul-lez-Durance Cedex (France); Petelet, Matthieu; Loredo, Alexandre [ISAT / LRMA, 49 rue Melle Bourgeois, BP 31, 58027 Nevers Cedex (France)

    2006-07-01

    In this work, the method of sensitivity analysis allowing to identify the inlet data the most influential on the variability of the responses (residual stresses and distortions). Classically, the sensitivity analysis is carried out locally what limits its validity domain to a given material. A global sensitivity analysis method is proposed; it allows to cover a material domain as wide as those of the steels series. A probabilistic modeling giving the variability of the material parameters in the steels series is proposed. The original aspect of this work consists in the use of the sampling method by latin hypercubes (LHS) of the material parameters which forms the inlet data (dependent of temperature) of the numerical simulations. Thus, a statistical approach has been applied to the welding numerical simulation: LHS sampling of the material properties, global sensitivity analysis what has allowed the reduction of the material parameterization. (O.M.)

  18. Numerical analysis

    CERN Document Server

    Rao, G Shanker

    2006-01-01

    About the Book: This book provides an introduction to Numerical Analysis for the students of Mathematics and Engineering. The book is designed in accordance with the common core syllabus of Numerical Analysis of Universities of Andhra Pradesh and also the syllabus prescribed in most of the Indian Universities. Salient features: Approximate and Numerical Solutions of Algebraic and Transcendental Equation Interpolation of Functions Numerical Differentiation and Integration and Numerical Solution of Ordinary Differential Equations The last three chapters deal with Curve Fitting, Eigen Values and Eigen Vectors of a Matrix and Regression Analysis. Each chapter is supplemented with a number of worked-out examples as well as number of problems to be solved by the students. This would help in the better understanding of the subject. Contents: Errors Solution of Algebraic and Transcendental Equations Finite Differences Interpolation with Equal Intervals Interpolation with Unequal Int...

  19. Groundwater flow dynamics of weathered hard-rock aquifers under climate-change conditions: an illustrative example of numerical modeling through the equivalent porous media approach in the north-western Pyrenees (France)

    Science.gov (United States)

    Jaunat, J.; Dupuy, A.; Huneau, F.; Celle-Jeanton, H.; Le Coustumer, P.

    2016-09-01

    A numerical groundwater model of the weathered crystalline aquifer of Ursuya (a major water source for the north-western Pyrenees region, south-western France) has been computed based on monitoring of hydrological, hydrodynamic and meteorological parameters over 3 years. The equivalent porous media model was used to simulate groundwater flow in the different layers of the weathered profile: from surface to depth, the weathered layer (5 · 10-8 ≤ K ≤ 5 · 10-7 m s-1), the transition layer (7 · 10-8 ≤ K ≤ 1 · 10-5 m s-1, the highest values being along major discontinuities), two fissured layers (3.5 · 10-8 ≤ K ≤ 5 · 10-4 m s-1, depending on weathering profile conditions and on the existence of active fractures), and the hard-rock basement simulated with a negligible hydraulic conductivity ( K = 1 10 -9 ). Hydrodynamic properties of these five calculation layers demonstrate both the impact of the weathering degree and of the discontinuities on the groundwater flow. The great agreement between simulated and observed hydraulic conditions allowed for validation of the methodology and its proposed use for application on analogous aquifers. With the aim of long-term management of this strategic aquifer, the model was then used to evaluate the impact of climate change on the groundwater resource. The simulations performed according to the most pessimistic climatic scenario until 2050 show a low sensitivity of the aquifer. The decreasing trend of the natural discharge is estimated at about -360 m3 y-1 for recharge decreasing at about -5.6 mm y-1 (0.8 % of annual recharge).

  20. Aerial Moisture Transport in the Earth Climate System: A Study of the Mean State and Perturbations Due to CO2-Doubling using Numerical Water Tracers and a Novel Linear Algebra Analysis Framework

    Science.gov (United States)

    Singh, H. A.; Bitz, C. M.; Nusbaumer, J. M.; Noone, D. C.

    2015-12-01

    Aerial moisture transport is fundamental to the climate system, and numerical water tracers (WTs) are a powerful tool for understanding this transport. Here, we present a novel matrix operator framework that permits systematic, rather than ad hoc, analysis of WT results. We use this framework to study moisture transport, from evaporation (or sublimation) to precipitation, in a state-of-the-art global climate model (GCM) which incorporates WTs. This framework separates moisture divergence over a given tagged region into local divergence (the export of locally-evaporated moisture) and remote convergence (the import of remotely-evaporated moisture). The remote convergence term may be further subdivided into zonal, meridional, intrabasin, and interbasin parts, and can be used to predict precipitation given a particular spatial pattern of evaporation (demonstrated in Figure 1a). Findings from analysis of the preindustrial mean state concur with findings from earlier moisture transport studies: water evaporated at the equator and high latitudes tends to precipitate locally, whereas water evaporated in the subtropics and midlatitudes tends to precipitate remotely; water evaporated in the subtropics diverges both equatorward and poleward of its source region, while water evaporated in the midlatitudes mostly diverges poleward. New insights from the method reveal fundamental differences between the major ocean basins, with the Atlantic basin having the largest local divergence, smallest remote convergence, and greatest interbasin moisture export. With quasi-equilibrium CO2-doubling, we find that a greater fraction of locally-evaporated moisture is exported, moisture exchange between ocean basins increases (shown in Figure 2c), and moisture convergence within a given basin shifts towards greater distances between moisture source and sink regions. These changes can be understood in terms of a greater moisture residence time with warming, or, equivalently, a robust increase in

  1. Mathematical and numerical analysis of a multi-velocity multi-fluid model for interpenetration of miscible fluids; Analyse mathematique et numerique d'un modele multifluide multivitesse pour l'interpenetration de fluides miscibles

    Energy Technology Data Exchange (ETDEWEB)

    Enaux, C

    2007-11-15

    The simulation of indirect laser implosion requires an accurate knowledge of the inter-penetration of the laser target materials turned into plasma. This work is devoted to the study of a multi-velocity multi-fluid model recently proposed by Scannapieco and Cheng (SC) to describe the inter-penetration of miscible fluids. In this document, we begin with presenting the SC model in the context of miscible fluids flow modelling. Afterwards, the mathematical analysis of the model is carried out (study of the hyperbolicity, existence of a strictly convex mathematical entropy, asymptotic analysis and diffusion limit). As a conclusion the problem is well set. Then, we focus on the problem of numerical resolution of systems of conservation laws with a relaxation source term, because SC model belongs to this class. The main difficulty of this task is to capture on a coarse grid the asymptotic behaviour of the system when the source term is stiff. The main contribution of this work lies in the proposition of a new technique, allowing us to construct a Lagrangian numerical flux taking into account the presence of the source term. This technique is applied first on the model-problem of a one-dimensional Euler system with friction, and then on the multi-fluid SC model. In both cases, we prove that the new scheme is asymptotic-preserving and entropic under a CFL-like condition. The two-dimensional extension of the scheme is done by using a standard alternate directions method. Some numerical results highlight the contribution of the new flux, compared with a standard Lagrange plus Remap scheme where the source term is processed using an operator splitting. (author)

  2. On the Sensitivity of L/E Analysis of Super-Kamiokande Atmospheric Neutrino Data to Neutrino Oscillation Part~2 --- Four Possible L/E Analyses for the Maximum Oscillation by the Numerical Computer Experiment ---

    CERN Document Server

    Konishi, E; Galkin, V I; Ishiwata, M; Nakamura, I; Takahashi, N; Kato, M; Misaki, A

    2010-01-01

    In the previous paper (Part~1), we have verified that the SK assumption on the direction does not hold in the analysis of neutrino events occurred inside the SK detector. We have made four possible L/E analyses, L_nu/E_nu, L_nu/E_mu, L_mu/E_nu and L_mu/E_mu. Among four kinds of L/E analyses, we have shown that only L_nu/E_nu analysis can give the signature of maximum oscillations clearly, while the L_mu/E_mu analysis which are really done by Super-Kamiokande Collaboration cannot give the maximum oscillation at all. It is thus concluded that Super-Kamiokande type experiment cannot find the maximum oscillation from L/E analysis. Therefore, we would suggest Super-Kamiokande Collaboration to re-analyze the zenith angle distribution of the neutrino events which occur inside the detector carefully.

  3. Numerical analysis

    CERN Document Server

    Scott, L Ridgway

    2011-01-01

    Computational science is fundamentally changing how technological questions are addressed. The design of aircraft, automobiles, and even racing sailboats is now done by computational simulation. The mathematical foundation of this new approach is numerical analysis, which studies algorithms for computing expressions defined with real numbers. Emphasizing the theory behind the computation, this book provides a rigorous and self-contained introduction to numerical analysis and presents the advanced mathematics that underpin industrial software, including complete details that are missing from m

  4. Numerical analysis

    CERN Document Server

    Brezinski, C

    2012-01-01

    Numerical analysis has witnessed many significant developments in the 20th century. This book brings together 16 papers dealing with historical developments, survey papers and papers on recent trends in selected areas of numerical analysis, such as: approximation and interpolation, solution of linear systems and eigenvalue problems, iterative methods, quadrature rules, solution of ordinary-, partial- and integral equations. The papers are reprinted from the 7-volume project of the Journal of Computational and Applied Mathematics on '/homepage/sac/cam/na2000/index.html<

  5. Numerical analyses of composite foundation of geosynthetic-encased stone columns subjected to vertical loading%竖向荷载下加筋碎石桩复合地基数值分析

    Institute of Scientific and Technical Information of China (English)

    陈建峰; 童振湄; 柳军修; 冯守中

    2013-01-01

    A three-dimensional finite element seepage-coupling numerical modeling is performed on a 6m thick soft foundation reinforced by geosynthetic-encasement stone column (GESC) with diameter of 0.8 m. The load transfer mechanism and deformation characteristics of GESC composite foundation subjected to vertical loading and excess pore pressure dissipation are analyzed using the numerical model. Compared to conventional stone column (CSC) composite foundation, the stress concentration ratio (SCR) in GESC composite foundation apparently increases while the excess pore pressure, settlement and column shaft bulging apparently decrease. The performance of GESC is further improved with an increase of geosynthetic stiffness. An apparent differential settlement between column and surrounding soil emerges to form a soil arching during consolidation of the surrounding soil, which leads to little change in SCR values after loading. Reinforcement length is found to have a significant influence on SCR and settlement in GESC composite foundation. Full length reinforcement is required for GESCs in composite foundation to assure their entire stiffness and less settlement.%采用三维有限元程序建立了一长为6 m、直径为0.8 m的加筋碎石桩复合地基流固耦合数值模型,分析了其在堆载和孔压消散过程中的荷载传递和变形特性。较传统碎石桩,加筋碎石桩复合地基桩土应力比显著增大,超孔压、沉降和桩身侧向变形显著减小,且随筋材刚度的增大,其性能进一步改善。加筋碎石桩复合地基在桩间土固结过程中产生明显的桩土差异沉降,形成土拱效应,使得堆载结束后桩土应力比变化很小。筋材长度对加筋碎石桩复合地基桩土应力比和沉降影响显著,应对其全长加筋才能保证桩体刚度和有效减少沉降。

  6. Numerical Integration

    Science.gov (United States)

    Sozio, Gerry

    2009-01-01

    Senior secondary students cover numerical integration techniques in their mathematics courses. In particular, students would be familiar with the "midpoint rule," the elementary "trapezoidal rule" and "Simpson's rule." This article derives these techniques by methods which secondary students may not be familiar with and an approach that…

  7. Numerical Relativity

    Science.gov (United States)

    Baker, John G.

    2009-01-01

    Recent advances in numerical relativity have fueled an explosion of progress in understanding the predictions of Einstein's theory of gravity, General Relativity, for the strong field dynamics, the gravitational radiation wave forms, and consequently the state of the remnant produced from the merger of compact binary objects. I will review recent results from the field, focusing on mergers of two black holes.

  8. Climatologie des états de mer en Atlantique nord-est : analyse du climat actuelet des évolutions futures sous scénarios de changement climatique par descente d'échelle dynamique et statistique

    OpenAIRE

    Laugel, Amélie

    2013-01-01

    Wave climate analysis is of utmost importance to understand the evolution and dynamics of coastal zones, to estimate the occurrence of extreme events, to design protections for ports, onshore and offshore infrastructure, to characterize wave resources for wave energy conversion, to quantify sediment erosion and accretion processes, et cetera. Thus, this thesis project aims to improve knowledge of wave climatology in the growing context of climate change prediction with a two-step approach: (i...

  9. Uncertainty assessment tool for climate change impact indicators

    Science.gov (United States)

    Otto, Juliane; Keup-Thiel, Elke; Jacob, Daniela; Rechid, Diana; Lückenkötter, Johannes; Juckes, Martin

    2015-04-01

    A major difficulty in the study of climate change impact indicators is dealing with the numerous sources of uncertainties of climate and non-climate data . Its assessment, however, is needed to communicate to users the degree of certainty of climate change impact indicators. This communication of uncertainty is an important component of the FP7 project "Climate Information Portal for Copernicus" (CLIPC). CLIPC is developing a portal to provide a central point of access for authoritative scientific information on climate change. In this project the Climate Service Center 2.0 is in charge of the development of a tool to assess the uncertainty of climate change impact indicators. The calculation of climate change impact indicators will include climate data from satellite and in-situ observations, climate models and re-analyses, and non-climate data. There is a lack of a systematic classification of uncertainties arising from the whole range of climate change impact indicators. We develop a framework that intends to clarify the potential sources of uncertainty of a given indicator and provides - if possible - solutions how to quantify the uncertainties. To structure the sources of uncertainties of climate change impact indicators, we first classify uncertainties along a 'cascade of uncertainty' (Reyer 2013). Our cascade consists of three levels which correspond to the CLIPC meta-classification of impact indicators: Tier-1 indicators are intended to give information on the climate system. Tier-2 indicators attempt to quantify the impacts of climate change on biophysical systems (i.e. flood risks). Tier-3 indicators primarily aim at providing information on the socio-economic systems affected by climate change. At each level, the potential sources of uncertainty of the input data sets and its processing will be discussed. Reference: Reyer, C. (2013): The cascade of uncertainty in modeling forest ecosystem responses to environmental change and the challenge of sustainable

  10. Phytoplankton and Climate

    Science.gov (United States)

    Moisan, John R.

    2009-01-01

    Ocean phytoplankton supply about half of the oxygen that humans utilize to sustain life. In this lecture, we will explore how phytoplankton plays a critical role in modulating the Earth's climate. These tiny organisms are the base of the Ocean's food web. They can modulate the rate at which solar heat is absorbed by the ocean, either through direct absorption or through production of highly scattering cellular coverings. They take up and help sequester carbon dioxide, a key greenhouse gas that modulated the Earth's climate. They are the source of cloud nucleation gases that are key to cloud formation/processes. They are also able to modify the nutrient budgets of the ocean through active uptake of inert atmospheric nitrogen. Climate variations have a pronounced impact on phytoplankton dynamics. Long term variations in the climate have been studied through geological interpretations on its influence on phytoplankton populations. The presentation will focus on presenting the numerous linkages that have been observed between climate and phytoplankton and further discuss how present climate change scenarios are likely to impact phytoplankton populations as well as present findings from several studies that have tried to understand how the climate might react to the feedbacks from these numerous climate-phytop|ankton linkages.

  11. From Richardson to early numerical weather prediction

    OpenAIRE

    Lynch, Peter

    2010-01-01

    The development of computer models for numerical simulation of the atmosphere and oceans is one of the great scientific triumphs of the past fifty years. These models have added enormously to our understanding of the complex processes in the atmosphere and oceans. The consequences for humankind of ongoing climate change will be far-reaching. Earth system models are the best means we have of predicting the future of our climate. The basic ideas of numerical forecasting and c...

  12. Numerical analysis of resonances induced by s wave neutrons in transmission time-of-flight experiments with a computer IBM 7094 II; Methodes d'analyse des resonances induites par les neutrons s dans les experiences de transmission par temps de vol et automatisation de ces methodes sur ordinateur IBM 7094 II

    Energy Technology Data Exchange (ETDEWEB)

    Corge, Ch. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-01-01

    Numerical analysis of transmission resonances induced by s wave neutrons in time-of-flight experiments can be achieved in a fairly automatic way on an IBM 7094/II computer. The involved computations are carried out following a four step scheme: 1 - experimental raw data are processed to obtain the resonant transmissions, 2 - values of experimental quantities for each resonance are derived from the above transmissions, 3 - resonance parameters are determined using a least square method to solve the over determined system obtained by equalling theoretical functions to the correspondent experimental values. Four analysis methods are gathered in the same code, 4 - graphical control of the results is performed. (author) [French] L'automatisation, sur ordinateur IBM 7094/II, de l'analyse des resonances induites par les neutrons s dans les experiences de transmission par temps de vol a ete accomplie en la decomposant selon un schema articule en quatre phases: 1 - le traitement des donnees experimentales brutes pour obtenir les transmissions interfero-resonnantes, 2 - la determination des grandeurs d'analyse a partir des transmissions precedentes, 3 - l'analyse proprement dite des resonances dont les parametres sont obtenus par la resolution d'un systeme surabondant. Quatre methodes d'analyse sont groupees en un meme programme, 4 - la procedure de verification graphique. (auteur)

  13. The CCPP-ARM Parameterization Testbed (CAPT): Where Climate Simulation Meets Weather Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, T J; Potter, G L; Williamson, D L; Cederwall, R T; Boyle, J S; Fiorino, M; Hnilo, J J; Olson, J G; Xie, S; Yio, J J

    2003-11-21

    To significantly improve the simulation of climate by general circulation models (GCMs), systematic errors in representations of relevant processes must first be identified, and then reduced. This endeavor demands, in particular, that the GCM parameterizations of unresolved processes should be tested over a wide range of time scales, not just in climate simulations. Thus, a numerical weather prediction (NWP) methodology for evaluating model parameterizations and gaining insights into their behavior may prove useful, provied that suitable adaptations are made for implementation in climate GCMs. This method entails the generation of short-range weather forecasts by realistically initialized climate GCM, and the application of six-hourly NWP analyses and observations of parameterized variables to evaluate these forecasts. The behavior of the parameterizations in such a weather-forecasting framework can provide insights on how these schemes might be improved, and modified parameterizations then can be similarly tested. In order to further this method for evaluating and analyzing parameterizations in climate GCMs, the USDOE is funding a joint venture of its Climate Change Prediction Program (CCPP) and Atmospheric Radiation Measurement (ARM) Program: the CCPP-ARM Parameterization Testbed (CAPT). This article elaborates the scientific rationale for CAPT, discusses technical aspects of its methodology, and presents examples of its implementation in a representative climate GCM. Numerical weather prediction methods show promise for improving parameterizations in climate GCMs.

  14. The Removal of Numerical Drift from Scientific Models

    Directory of Open Access Journals (Sweden)

    John Collins

    2013-04-01

    Full Text Available Computer programs often behave differently under different compilers or in different computingenvironments. Relative debugging is a collection of techniques by which these differences are analysed.Differences may arise because ofdifferent interpretations of errors in the code, because of bugs in thecompilers or because of numerical drift, and all of these were observed in the present study. Numericaldrift arises when small and acceptable differences in values computed by different systems areintegrated, so that the results drift apart. This is well understood and need not degrade the validity of theprogram results. Coding errors and compiler bugs may degrade the results and should be removed. Thispaper describes a technique for the comparison of two program runs which removes numerical drift andtherefore exposes coding and compiler errors. The procedure is highly automated and requires very littleintervention by the user. The technique is applied to the Weather Research and Forecasting model, themost widely used weather and climate modelling code

  15. Numerical analysis

    CERN Document Server

    Jacques, Ian

    1987-01-01

    This book is primarily intended for undergraduates in mathematics, the physical sciences and engineering. It introduces students to most of the techniques forming the core component of courses in numerical analysis. The text is divided into eight chapters which are largely self-contained. However, with a subject as intricately woven as mathematics, there is inevitably some interdependence between them. The level of difficulty varies and, although emphasis is firmly placed on the methods themselves rather than their analysis, we have not hesitated to include theoretical material when we consider it to be sufficiently interesting. However, it should be possible to omit those parts that do seem daunting while still being able to follow the worked examples and to tackle the exercises accompanying each section. Familiarity with the basic results of analysis and linear algebra is assumed since these are normally taught in first courses on mathematical methods. For reference purposes a list of theorems used in the t...

  16. 中国内陆河流域植被对气候变化的敏感性差异%Sensitivity analyses of different vegetations responding to climate change in inland river basin of China

    Institute of Scientific and Technical Information of China (English)

    HOU Peng; WANG Qiao; CAO Guangzhen; WANG Changzuo; ZHAN Zhiming; YANG Bingfeng

    2012-01-01

    @@%Terrestrial ecosystem and climate system are closely related to each other.Faced with the unavoidable global climate change,it is important to investigate terrestrial ecosystem responding to climate change.In inland river basin of arid and semi-arid regions in China,sensitivity difference of vegetation responding to climate change from 1998 to 2007 was analyzed in this paper.(1) Differences in the global spatio-temporal distribution of vegetation and climate are obvious.The vegetation change shows a slight degradation in this whole region.Degradation is more obvious in densely vegetated areas.Temperature shows a general downward trend with a linear trend coefficient of-1.1467.Conversely,precipitation shows an increasing trend with a linear trend coefficient of 0.3896.(2) About the central tendency response,there are similar features in spatial distribution of both NDVI responding to precipitation (NDVI-P) and NDVI responding to AI (NDVI-AI),which are contrary to that of NDVI responding to air temperature (NDVI-T).Typical sensitivity region of NDVI-P and NDVI-AI mainly covers the northern temperate arid steppe and the northern temperate desert steppe.NDVI-T typical sensitivity region mainly covers the northern temperate desert steppe.(3) Regarding the fluctuation amplitude response,NDVI-T is dominated by the lower sensitivity,typical regions of the warm temperate shrubby,selui-shrubby,bare extreme dry desert,and northern temperate meadow steppe in the east and temperate semi-shrubby,dwarf arboreous desert in the north are high response.(4) Fluctuation amplitude responses between NDVI-P and NDVI-AI present a similar spatial distribution.The typical sensitivity region mainly covers the northern temperate desert steppe.There are various linear change trend responses of NDVI-T,NDVI-P and NDVI-AI.As to the NDVI-T and NDVI-AI,which are influenced by the boundary effect of semi-arid and semi-humid climate zones,there is less correlation of their linear change tendency

  17. Mammoth ecosystem: Climatic areal, animal's density and cause of extinctions

    Science.gov (United States)

    Zimov, S.; Zimov, N.; Zimova, G.; Chapin, S. F.

    2008-12-01

    During the last glaciations Mammoth Ecosystem (ME) occupied territory from present-day France to Canada and from the Arctic islands to China. This ecosystem played major role in global carbon cycle and human settling around the planet. Causes of extinction of this ecosystem are debatable. Analyses of hundreds of radiocarbon dates of ME animal fossil remains showed that warming and moistening of climate wasn't accompanied by animal extinction. On the opposite, on the north right after the warming rise of herbivore population was observed. Reconstruction of ME climatic areal showed that its climatic optimum lies within range of annual precipitation of 200-350 mm and average summer temperatures of +8-+12oC which corresponds with modern climate of Northern Siberia. Analyses of bones and skeletons concentrations in permafrost of Northern Siberia showed that animal density in ME was similar to African savannah. That was a high productive ecosystem that could sustain in wide variety of climates because numerous herbivores maintained there pastures themselves.

  18. The impact of possible climate catastrophes on global warming policy

    International Nuclear Information System (INIS)

    Recent studies on global warming have introduced the inherent uncertainties associated with the costs and benefits of climate policies and have often shown that abatement policies are likely to be less aggressive or postponed in comparison to those resulting from traditional cost-benefit analyses (CBA). Yet, those studies have failed to include the possibility of sudden climate catastrophes. The aim of this paper is to account simultaneously for possible continuous and discrete damages resulting from global warming, and to analyse their implications on the optimal path of abatement policies. Our approach is related to the new literature on investment under uncertainty, and relies on some recent developments of the real option in which we incorporated negative jumps (climate catastrophes) in the stochastic process corresponding to the net benefits associated with the abatement policies. The impacts of continuous and discrete climatic risks can therefore be considered separately. Our numerical applications lead to two main conclusions: (i) gradual, continuous uncertainty in the global warming process is likely to delay the adoption of abatement policies as found in previous studies, with respect to the standard CBA; however (ii) the possibility of climate catastrophes accelerates the implementation of these policies as their net discounted benefits increase significantly

  19. Climate science: Misconceptions of global catastrophe

    Science.gov (United States)

    Rocklöv, Joacim

    2016-04-01

    American attitudes to changing weather, and therefore to climate change, have been analysed on the basis of US migration patterns since the 1970s. The findings have implications for the success of global climate policies. See Letter p.357

  20. Climate Change

    Science.gov (United States)

    ... in a place over a period of time. Climate change is major change in temperature, rainfall, snow, or ... by natural factors or by human activities. Today climate changes are occurring at an increasingly rapid rate. Climate ...

  1. NUMERICAL ANALYSES OF THE UNDERGROUND EXPLOITATION OF DIMENSION STONE

    OpenAIRE

    1996-01-01

    Underground exploitation of dimension stone is spreading lately for three main reasons; economy, organisation and environment. Moreover, underground openings can be used for many purposes. Underground exploitation is different from surface quarrying only in the first stage, the removal of top slice, descending slices are worked as in conventional quarries. In underground stone quarries, stability problems require adequate studies in order to avoid expensive artificial support measures, ...

  2. Numerical Analysis of Multiscale Computations

    CERN Document Server

    Engquist, Björn; Tsai, Yen-Hsi R

    2012-01-01

    This book is a snapshot of current research in multiscale modeling, computations and applications. It covers fundamental mathematical theory, numerical algorithms as well as practical computational advice for analysing single and multiphysics models containing a variety of scales in time and space. Complex fluids, porous media flow and oscillatory dynamical systems are treated in some extra depth, as well as tools like analytical and numerical homogenization, and fast multipole method.

  3. NASA and the National Climate Assessment: Promoting awareness of NASA Earth science

    Science.gov (United States)

    Leidner, A. K.

    2014-12-01

    NASA Earth science observations, models, analyses, and applications made significant contributions to numerous aspects of the Third National Climate Assessment (NCA) report and are contributing to sustained climate assessment activities. The agency's goal in participating in the NCA was to ensure that NASA scientific resources were made available to understand the current state of climate change science and climate change impacts. By working with federal agency partners and stakeholder communities to develop and write the report, the agency was able to raise awareness of NASA climate science with audiences beyond the traditional NASA community. To support assessment activities within the NASA community, the agency sponsored two competitive programs that not only funded research and tools for current and future assessments, but also increased capacity within our community to conduct assessment-relevant science and to participate in writing assessments. Such activities fostered the ability of graduate students, post-docs, and senior researchers to learn about the science needs of climate assessors and end-users, which can guide future research activities. NASA also contributed to developing the Global Change Information System, which deploys information from the NCA to scientists, decision makers, and the public, and thus contributes to climate literacy. Finally, NASA satellite imagery and animations used in the Third NCA helped the pubic and decision makers visualize climate changes and were frequently used in social media to communicate report key findings. These resources are also key for developing educational materials that help teachers and students explore regional climate change impacts and opportunities for responses.

  4. An improved numerical method for nonlinear terms of spectral model and its applications

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    At present, the spectral model is one of the most widely applied numerical models in the research of numerical prediction and climatic variation. To improve the precision and efficiency of spectral method can greatly contribute to the development of numerical prediction. As the core part of spectral method, the calculating method of nonlinear terms always concentrates on numerical solution of atmospheric dynamical processes in the spectral space. However, there was little study in this field in the late thirty years. According to the principle of nonlinear term calculation with the dimensionality degradation and latitudinal perfect spectral method, we designed a new nonlinear term calculating method and made it compatible well with the common numerical algorithms of the spectral model used internationally. With an own-designed spectral dynamical framework suiting for the numerical application in common uses, theoretical analyses and numerical experiments have also been deeply conducted to compare our new method with the widely-used transform method in an attempt to advance the development of numerical algorithms of spectral model.

  5. Effects of climate variability and climate change on crop production in southern Mali

    NARCIS (Netherlands)

    Traore, B.; Corbeels, M.; Wijk, van M.T.; Rufino, M.C.; Giller, K.E.

    2013-01-01

    In West Africa predictions of future changes in climate and especially rainfall are highly uncertain, and up to now no long-term analyses are available of the effects of climate on crop production. This study analyses long-term trends in climate variability at N'Tarla and Sikasso in southern Mali us

  6. The importance of buisiness climate and people climate on regional rerformance

    DEFF Research Database (Denmark)

    Eriksson, Rikard; Hansen, Høgni Kalsø; Lindgren, Urban

    2014-01-01

    capita (GRP) at the regional level, this paper analyses the influence of business climate (business-friendly assets) and people climate (amenities). Based on panel-data regressions, it is shown that both business and people climate are related to regional performance. The exact nature...... of these relationships is, however, dependent on how both regional performance and business or people climate is defined....

  7. Future Climate Analysis

    International Nuclear Information System (INIS)

    This report documents an analysis that was performed to estimate climatic variables for the next 10,000 years by forecasting the timing and nature of climate change at Yucca Mountain, Nevada, the site of a repository for spent nuclear fuel and high-level radioactive waste. The future-climate estimates are based on an analysis of past-climate data from analog meteorological stations, and this report provides the rationale for the selection of these analog stations. The stations selected provide an upper and a lower climate bound for each future climate, and the data from those sites will provide input to the following reports: ''Simulation of Net Infiltration for Present-Day and Potential Future Climates'' (BSC 2004 [DIRS 170007]), ''Total System Performance Assessment (TSPA) Model/Analysis for the License Application'' (BSC 2004 [DIRS 168504]), ''Features, Events, and Processes in UZ Flow and Transport'' (BSC 2004 [DIRS 170012]), and ''Features, Events, and Processes in SZ Flow and Transport'' (BSC 2004 [DIRS 170013]). Forecasting long-term future climates, especially for the next 10,000 years, is highly speculative and rarely attempted. A very limited literature exists concerning the subject, largely from the British radioactive waste disposal effort. The discussion presented here is one available forecasting method for establishing upper and lower bounds for future climate estimates. The selection of different methods is directly dependent on the available evidence used to build a forecasting argument. The method used here involves selecting a particular past climate from many past climates, as an analog for future climate. While alternative analyses are possible for the case presented for Yucca Mountain, the evidence (data) used would be the same and the conclusions would not be expected to drastically change. Other studies might develop a different rationale or select other past climates resulting in a different future climate analog. Other alternative

  8. Future Climate Analysis

    Energy Technology Data Exchange (ETDEWEB)

    C. G. Cambell

    2004-09-03

    This report documents an analysis that was performed to estimate climatic variables for the next 10,000 years by forecasting the timing and nature of climate change at Yucca Mountain, Nevada, the site of a repository for spent nuclear fuel and high-level radioactive waste. The future-climate estimates are based on an analysis of past-climate data from analog meteorological stations, and this report provides the rationale for the selection of these analog stations. The stations selected provide an upper and a lower climate bound for each future climate, and the data from those sites will provide input to the following reports: ''Simulation of Net Infiltration for Present-Day and Potential Future Climates'' (BSC 2004 [DIRS 170007]), ''Total System Performance Assessment (TSPA) Model/Analysis for the License Application'' (BSC 2004 [DIRS 168504]), ''Features, Events, and Processes in UZ Flow and Transport'' (BSC 2004 [DIRS 170012]), and ''Features, Events, and Processes in SZ Flow and Transport'' (BSC 2004 [DIRS 170013]). Forecasting long-term future climates, especially for the next 10,000 years, is highly speculative and rarely attempted. A very limited literature exists concerning the subject, largely from the British radioactive waste disposal effort. The discussion presented here is one available forecasting method for establishing upper and lower bounds for future climate estimates. The selection of different methods is directly dependent on the available evidence used to build a forecasting argument. The method used here involves selecting a particular past climate from many past climates, as an analog for future climate. While alternative analyses are possible for the case presented for Yucca Mountain, the evidence (data) used would be the same and the conclusions would not be expected to drastically change. Other studies might develop a different rationale or select other past

  9. The volcanic contribution to climate change of the past 100 years

    International Nuclear Information System (INIS)

    Volcanic eruptions which inject large amounts of sulfur-rich gas into the stratosphere produce dust veils which last several years and cool the earth's surface. At the same time these dust veils absorb enough solar radiation to warm the stratosphere. Since these temperature changes at the earth's surface and in the stratosphere are both in the opposite direction to the hypothesized effects from greenhouse gases, they act to delay and mask the detection of greenhouse effects on the climate system. A large portion of the global climate change of the past 100 years may be due to the effects of volcanoes, but a definitive answer is not yet clear. While effects over several years have been demonstrated with both data studies and numerical models, long-term effects, while found in climate model calculations, await confirmation with more realistic models. In this paper chronologies of past volcanic eruptions and the evidence from data analyses and climate model calculations are reviewed

  10. Temperate climate - Innovative outputs nexus

    OpenAIRE

    Coccia, M.

    2014-01-01

    Technological change is a vital human activity that interacts with geographic factors and environment. The purpose of the study here is to analyse the relationship between geo-climate zones of the globe and technological outputs in order to detect favourable areas that spur higher technological change and, as a consequence, human development. The main finding is that innovative outputs are higher in geographical areas with a temperate climate (latitudes). In fact, warm temperate climates are ...

  11. Climate change and group dynamics

    NARCIS (Netherlands)

    Postmes, Tom

    2015-01-01

    The characteristics and views of people sceptical about climate change have been analysed extensively. A study now confirms that sceptics in the US have some characteristics of a social movement, but shows that the same group dynamics propel believers

  12. Apports de l’analyse de la conformité réglementaire, de l’analyse des risques professionnels et de l'évaluation du climat de sécurité à la construction de la culture de sécurité

    OpenAIRE

    Lefranc, Guénolé

    2012-01-01

    Safety culture is increasingly important to the corporate agenda. The SafetyCulture concept is not new, but gained popularity in the late 80s following the Chernobyl accident. The main cause of the disaster was said to be a deficient Safety culture.The term is now used widely and definitions are numerous. The Safety culture literature contains three major explanatory factors shaping the formation of a safety culture: "organizational", "behavioural" and "psychological".The objective of this th...

  13. Climate Projections and Uncertainty Communication.

    Science.gov (United States)

    Joslyn, Susan L; LeClerc, Jared E

    2016-01-01

    Lingering skepticism about climate change might be due in part to the way climate projections are perceived by members of the public. Variability between scientists' estimates might give the impression that scientists disagree about the fact of climate change rather than about details concerning the extent or timing. Providing uncertainty estimates might clarify that the variability is due in part to quantifiable uncertainty inherent in the prediction process, thereby increasing people's trust in climate projections. This hypothesis was tested in two experiments. Results suggest that including uncertainty estimates along with climate projections leads to an increase in participants' trust in the information. Analyses explored the roles of time, place, demographic differences (e.g., age, gender, education level, political party affiliation), and initial belief in climate change. Implications are discussed in terms of the potential benefit of adding uncertainty estimates to public climate projections. PMID:26695995

  14. Climate Projections and Uncertainty Communication.

    Science.gov (United States)

    Joslyn, Susan L; LeClerc, Jared E

    2016-01-01

    Lingering skepticism about climate change might be due in part to the way climate projections are perceived by members of the public. Variability between scientists' estimates might give the impression that scientists disagree about the fact of climate change rather than about details concerning the extent or timing. Providing uncertainty estimates might clarify that the variability is due in part to quantifiable uncertainty inherent in the prediction process, thereby increasing people's trust in climate projections. This hypothesis was tested in two experiments. Results suggest that including uncertainty estimates along with climate projections leads to an increase in participants' trust in the information. Analyses explored the roles of time, place, demographic differences (e.g., age, gender, education level, political party affiliation), and initial belief in climate change. Implications are discussed in terms of the potential benefit of adding uncertainty estimates to public climate projections.

  15. Triple oxygen and sulfur isotope analyses of sulfate extracted from voluminous volcanic ashes in the Oligocene John Day Formation: insight into dry climate conditions and ozone contribution to supereruptions

    Science.gov (United States)

    Workman, J.; Bindeman, I. N.; Martin, E.; Retallack, G.; Palandri, J. L.; Weldon, N.

    2014-12-01

    Large volume pyroclastic silicic eruptions emit hundreds of megatons of SO2 into the troposphere and stratosphere that is oxidized into sulfuric acid (H2SO4) by a variety of reactions with mass independent oxygen signatures (MIF), Δ17O>0. Sulfuric acid is then preserved as gypsum in parental volcanic deposits. Diagenic effects are mass dependent and can dilute, but otherwise do not affect MIF ratios. Pleistocene Yellowstone and Bishop tuffs and modern volcanic eruptions preserved under arid climate conditions in North American playa lakes, preserve small amounts of volcanic sulfate as gypsum. This gypsum's Δ17O>0, in combination with isotopic variations of δ18O, δ33S and δ34S is distinct from sedimentary sulfate and reveals its original MIF sulfate isotopic signal and the effect of super eruptions on the atmosphere, and ozone consumption in particular. We use linear algebraic equations to resolve volcanic versus sedimentary (MIF=0) sources. We have found that many large volume ignimbrites have very high initial Δ17O in volcanic sulfate that can only be acquired from reaction with stratospheric ozone. We here investigate nine thick (>2 m) ash beds ranging in age from ~33-23 Ma in the John Day Formation of central Oregon, including massive 28.6 Ma Picture Gorge tuff of newly identified Crooked River supercaldera. The 28.6 Ma Picture Gorge tuff (PGT) has the highest measured Δ17O of 3.5‰, and other tuffs (Tin Roof, Biotite, Deep Creek) have +1.3 to 3.4‰ Δ17O excesses. Sulfate from modern smaller tropospheric eruptions studied for comparison have a resolvable 0.4‰ range consistent with liquid-phase based H2O2 oxidation. The PGT is coeval with the ignimbrite flare-up in western N. America, the 28-29 Ma eruption of the 5000 km3 Fish Canyon tuff and the 28 Ma Never Summer Field eruption in Nebraska-Colorado that have the highest measured Δ17O of 6‰ (Bao et al. 2003). We speculate on the climatic/atmospheric effects of these multiple ~28 Ma supereruptions

  16. The climate file

    International Nuclear Information System (INIS)

    A series of interviews of a member of the IPCC (Intergovernmental Panel on Climate Change) and of researchers gives an overview of scientific knowledge on climate, discusses what could be a good agreement at the Copenhagen conference, outlines what is at stake in these negotiations, and proposes an overview of the French policy for the struggle against climate change. An article comments the content of a report published by the CAS (Centre d'Analyse Strategique), and more particularly the position of Russia and of the OPEC before the Copenhagen negotiations. A last article comments the results of three opinion surveys made in France about climate change, its origins and solutions, and about the representation French people have of greenhouse effect

  17. Stable isotopic analyses in paleoclimatic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Wigand, P.E. [Univ. and Community College System of Nevada, Reno, NV (United States)

    1995-09-01

    Most traditional paleoclimatic proxy data have inherent time lags between climatic input and system response that constrain their use in accurate reconstruction of paleoclimate chronology, scaling of its variability, and the elucidation of the processes that determine its impact on the biotic and abiotic environment. With the exception of dendroclimatology, and studies of short-lived organisms and pollen recovered from annually varved lacustrine sediments, significant periods of time ranging from years, to centuries, to millennia may intervene between climate change and its first manifestation in paleoclimatic proxy data records. Reconstruction of past climate through changes in plant community composition derived from pollen sequences and plant remains from ancient woodrat middens, wet environments and dry caves all suffer from these lags. However, stable isotopic analyses can provide more immediate indication of biotic response to climate change. Evidence of past physiological response of organisms to changes in effective precipitation as climate varies can be provided by analyses of the stable isotopic content of plant macrofossils from various contexts. These analyses consider variation in the stable isotopic (hydrogen, oxygen and carbon) content of plant tissues as it reflects (1) past global or local temperature through changes in meteoric (rainfall) water chemistry in the case of the first two isotopes, and (2) plant stress through changes in plant respiration/transpiration processes under differing water availability, and varying atmospheric CO, composition (which itself may actually be a net result of biotic response to climate change). Studies currently being conducted in the Intermountain West indicate both long- and short-term responses that when calibrated with modem analogue studies have the potential of revealing not only the timing of climate events, but their direction, magnitude and rapidity.

  18. Analysis of climatically relevant processes in the troposphere using ground-based remote measuring methods (windprofiler/RASS). Final report; Analyse klimatisch relevanter Prozesse in der Troposphaere mit Hilfe bodengebundener Fernerkundungsmethoden (Windprofiler/RASS). Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Steinhagen, H.; Christoph, A.; Engelbart, D.; Goersdorf, U.; Hirsch, L.; Lippmann, J.; Neisser, J.; Wergen, W.

    1995-09-01

    In the framework of the present research project the Meterological Observatory of Lindenberg (MOL) was equipped with the scientific and technical means necessary for the future operational application at the German weather service of ground-based remote sounding technologies such as `windprofiler radar`, radio-acoustic sounding system (RASS). Several case studies were used to demonstrate the multifarious possibilities of analysing mesoscale tropospheric structures by means of windprofiler radar and RASS. Besides this, further information such as mixing layer thickness and heat flux were derived from windprofiler and RASS measurements and the applied algorithms were tried on case examples. (orig./AKF) [Deutsch] Im Rahmen dieses Forschungsvorhabens sind am Meteorologischen Observatorium Lindenberg (MOL) wissenschaftliche und technische Voraussetzungen fuer eine zukuenftige operationelle Anwendung aktiver bodengebundener Fernsondierungstechnologien, wie `Windprofiler-Radar` und `Radio-Akustisches-Sondierungs-System (RASS)` im Deutschen Wetterdienst geschaffen worden. An Hand mehrerer Fallstudien wurden die vielfaeltigen Moeglichkeiten zur Analyse mesoskaliger troposphaerischer Strukturen mit Windprofiler-Radar und RASS demonstriert. Darueber hinaus wurden aus Windprofiler-/RASS-Messungen weiterfuehrende Informationen, wie Mischungsschichthoehe und Waermefluss abgeleitet und die entsprechenden Algorithmen am Fallbeispielen erprobt. (orig./AKF)

  19. Developing the architecture for the Climate Information Portal for Copernicus

    Science.gov (United States)

    Som de Cerff, Wim; Thijsse, Peter; Plieger, Maarten; Pascoe, Stephen; Jukes, Martin; Leadbetter, Adam; Goosen, Hasse; de Vreede, Ernst

    2015-04-01

    Climate change is impacting the environment, society and policy decisions. Information about climate change is available from many sources, but not all of them are reliable. The CLIPC project is developing a portal to provide a single point of access for authoritative scientific information on climate change. This ambitious objective is made possible through the Copernicus Earth Observation Programme for Europe, which will deliver a new generation of environmental measurements of climate quality. The data about the physical environment which is used to inform climate change policy and adaptation measures comes from several categories: satellite measurements, terrestrial observing systems, model projections and simulations and from re-analyses (syntheses of all available observations constrained with numerical weather prediction systems). These data categories are managed by different communities: CLIPC will provide a single point of access for the whole range of data. Information on data value and limitations will be provided as part of a knowledge base of authoritative climate information. The impacts of climate change on society will generally reflect a range of different environmental and climate system changes, and different sectors and actors within society will react differently to these changes. The CLIPC portal will provide some a number of indicators showing impacts on specific sectors which have been generated using a range of factors selected through structured expert consultation. It will also, as part of the transformation services, allow users to explore the consequences of using different combinations of driving factors which they consider to be of particular relevance to their work or life. The portal will provide information on the scientific quality and pitfalls of such transformations to prevent misleading usage of the results. The CLIPC project will not be able to process a comprehensive range of climate change impacts on the physical

  20. Climate Informatics

    Science.gov (United States)

    Monteleoni, Claire; Schmidt, Gavin A.; Alexander, Francis J.; Niculescu-Mizil, Alexandru; Steinhaeuser, Karsten; Tippett, Michael; Banerjee, Arindam; Blumenthal, M. Benno; Ganguly, Auroop R.; Smerdon, Jason E.; Tedesco, Marco

    2013-01-01

    The impacts of present and potential future climate change will be one of the most important scientific and societal challenges in the 21st century. Given observed changes in temperature, sea ice, and sea level, improving our understanding of the climate system is an international priority. This system is characterized by complex phenomena that are imperfectly observed and even more imperfectly simulated. But with an ever-growing supply of climate data from satellites and environmental sensors, the magnitude of data and climate model output is beginning to overwhelm the relatively simple tools currently used to analyze them. A computational approach will therefore be indispensable for these analysis challenges. This chapter introduces the fledgling research discipline climate informatics: collaborations between climate scientists and machine learning researchers in order to bridge this gap between data and understanding. We hope that the study of climate informatics will accelerate discovery in answering pressing questions in climate science.

  1. Nonlinearly combined impacts of initial perturbation from human activities and parameter perturbation from climate change on the grassland ecosystem

    Directory of Open Access Journals (Sweden)

    G. Sun

    2011-11-01

    Full Text Available Human activities and climate change are important factors that affect grassland ecosystems. A new optimization approach, the approach of conditional nonlinear optimal perturbation (CNOP related to initial and parameter perturbations, is employed to explore the nonlinearly combined impacts of human activities and climate change on a grassland ecosystem using a theoretical grassland model. In our study, it is assumed that the initial perturbations and parameter perturbations are regarded as human activities and climate change, respectively. Numerical results indicate that the climate changes causing the maximum effect in the grassland ecosystem are different under disparate intensities of human activities. This implies the pattern of climate change is very critical to the maintenance or degradation of grassland ecosystem in light of high intensity of human activities and that the grassland ecosystem should be rationally managed when the moisture index decreases. The grassland ecosystem influenced by the nonlinear combination of human activities and climate change undergoes abrupt change, while the grassland ecosystem affected by other types of human activities and climate change fails to show the abrupt change under a certain range of perturbations with the theoretical model. The further numerical analyses also indicate that the growth of living biomass and the evaporation from soil surface shaded by the wilted biomass may be crucial factors contributing to the abrupt change of the grassland equilibrium state within the theoretical model.

  2. The application analyses for primary spectrum pyrometer

    Institute of Scientific and Technical Information of China (English)

    FU; TaiRan

    2007-01-01

    In the applications of primary spectrum pyrometry, based on the dynamic range and the minimum sensibility of the sensor, the application issues, such as the measurement range and the measurement partition, were investigated through theoretical analyses. For a developed primary spectrum pyrometer, the theoretical predictions of measurement range and the distributions of measurement partition were presented through numerical simulations. And the measurement experiments of high-temperature blackbody and standard temperature lamp were processed to further verify the above theoretical analyses and numerical results. Therefore the research in the paper provides the helpful supports for the applications of primary spectrum pyrometer and other radiation pyrometers.……

  3. Numerical Propulsion System Simulation

    Science.gov (United States)

    Naiman, Cynthia

    2006-01-01

    The NASA Glenn Research Center, in partnership with the aerospace industry, other government agencies, and academia, is leading the effort to develop an advanced multidisciplinary analysis environment for aerospace propulsion systems called the Numerical Propulsion System Simulation (NPSS). NPSS is a framework for performing analysis of complex systems. The initial development of NPSS focused on the analysis and design of airbreathing aircraft engines, but the resulting NPSS framework may be applied to any system, for example: aerospace, rockets, hypersonics, power and propulsion, fuel cells, ground based power, and even human system modeling. NPSS provides increased flexibility for the user, which reduces the total development time and cost. It is currently being extended to support the NASA Aeronautics Research Mission Directorate Fundamental Aeronautics Program and the Advanced Virtual Engine Test Cell (AVETeC). NPSS focuses on the integration of multiple disciplines such as aerodynamics, structure, and heat transfer with numerical zooming on component codes. Zooming is the coupling of analyses at various levels of detail. NPSS development includes capabilities to facilitate collaborative engineering. The NPSS will provide improved tools to develop custom components and to use capability for zooming to higher fidelity codes, coupling to multidiscipline codes, transmitting secure data, and distributing simulations across different platforms. These powerful capabilities extend NPSS from a zero-dimensional simulation tool to a multi-fidelity, multidiscipline system-level simulation tool for the full development life cycle.

  4. Celebrity Climate Contrarians: Understanding a keystone species in contemporary climate science-policy-public interactions

    Science.gov (United States)

    Boykoff, M. T.

    2012-12-01

    Since the 1980s, a keystone species called 'climate contrarians' has emerged and thrived. Through resistance to dominant interpretations of scientific evidence, and often outlier views on optimal responses to climate threats, contrarians have raised many meta-level questions: for instance, questions involve to what extent have their varied interventions been effective in terms of sparking a new and wise Copernican revolution; or do their amplified voices instead service entrenched carbon-based industry interests while they blend debates over 'climate change' with other culture wars? While the value of their influence has generated numerous debates, there is no doubt that climate contrarians have had significant influence on climate science, policy and public communities in ways that are larger than would be expected from their relative abundance in society. As such, a number of these actors have achieved 'celebrity status' in science-policy circles, and, at times, larger public spaces. This presentation focuses on how - particularly through amplified mass media attention to their movements - various outlier interventions have demonstrated themselves to be (often deliberately) detrimental to efforts that seek to enlarge rather than constrict the spectrum of possibility for mobilizing appropriate responses to ongoing climate challenges. Also, this work analyses the growth pathways of these charismatic megafauna through interview data and participant observations completed by the author at the 2011 Heartland Institute's Sixth International Conference on Climate Change. This provides detail on how outlier perspectives characterized as climate contrarians do work in these spaces under the guise of public intellectualism to achieve intended goals and objectives. The research undertaken and related in the presentation here seeks to better understand motivations that prop up these contrarian stances, such as possible ideological or evidentiary disagreement to the orthodox

  5. Techniques for analyses of trends in GRUAN data

    Directory of Open Access Journals (Sweden)

    G. E. Bodeker

    2014-12-01

    Full Text Available The Global Climate Observing System (GCOS Reference Upper Air Network (GRUAN provides reference quality RS92 radiosonde measurements of temperature, pressure and humidity. A key attribute of reference quality measurements, and hence GRUAN data, is that each datum has a well characterised and traceable estimate of the measurement uncertainty. The long-term homogeneity of the measurement records, and their well characterised uncertainties, make these data suitable for reliably detecting changes in global and regional climate on decadal time scales. Considerable effort is invested in GRUAN operations to (i describe and analyse all sources of measurement uncertainty to the extent possible, (ii quantify and synthesize the contribution of each source of uncertainty to the total measurement uncertainty, and (iii verify that the evaluated net uncertainty is within the required target uncertainty. However, if the climate science community is not sufficiently well informed on how to capitalize on this added value, the significant investment in estimating meaningful measurement uncertainties is largely wasted. This paper presents and discusses the techniques that will need to be employed to reliably quantify long-term trends in GRUAN data records. A pedagogical approach is taken whereby numerical recipes for key parts of the trend analysis process are explored. The paper discusses the construction of linear least squares regression models for trend analysis, boot-strapping approaches to determine uncertainties in trends, dealing with the combined effects of autocorrelation in the data and measurement uncertainties in calculating the uncertainty on trends, best practice for determining seasonality in trends, how to deal with co-linear basis functions, and interpreting derived trends. Synthetic data sets are used to demonstrate these concepts which are then applied to a first analysis of temperature trends in RS92 radiosonde upper air soundings at the GRUAN

  6. Analyses on Four Climate Abnormalities of China in 2011 and Their Causes%2011年中国4次成灾性气候异常及其原因分析

    Institute of Scientific and Technical Information of China (English)

    梁丰; 汤懋苍; 高晓清; 惠小英; 郭维栋

    2013-01-01

    Four major climate anomalies of China in 2011,including severe drought in the middle reach of Yangtze River in spring and summer,the drought-flood abrupt alternation in the middle and lower reaches of the Yangtze River in early June,the autumn flood in middle reach of the Yellow River and freezing rain in winter of Guizhou are analyzed.The results show that they are well related with earthquakes.When the earthquake occurred,the geothermal vortex will develop that lead to precipitation increasing in this area.And after a period of earthquake,the geothermal vortex will weakened that cause to precipitation reducing.It is the result of big underground cold vortex.When two earthquakes occurred in one year,the beat vortex will form in the middle of them and it has a tremendous impact to flood.%为了研究地震与气候异常的关系,从地震活动的角度对2011年发生在我国的4次成灾性气候异常进行了分析.结果表明,2011年长江中游春、夏季大旱的直接原因是3月24日发生在缅甸的7.2级地震;长江中下游6月上旬出现旱涝急转则与3月11日日本东部的9.0级地震及缅甸地震密不可分;鄂赣交界发生的4.6级地震对黄河中游秋汛的影响最为明显,这是“震侧强涡”造成的结果;2012年1月贵州冻雨较多也是受到印度锡金和我国东海两个地震形成的“拍涡”影响,这表明地震活动是影响天气、气候变化的可能原因之一.

  7. Evaluating Parameterizations in General Circulation Models: Climate Simulation Meets Weather Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, T J; Potter, G L; Williamson, D L; Cederwall, R T; Boyle, J S; Fiorino, M; Hnilo, J J; Olson, J G; Xie, S; Yio, J J

    2004-05-06

    To significantly improve the simulation of climate by general circulation models (GCMs), systematic errors in representations of relevant processes must first be identified, and then reduced. This endeavor demands that the GCM parameterizations of unresolved processes, in particular, should be tested over a wide range of time scales, not just in climate simulations. Thus, a numerical weather prediction (NWP) methodology for evaluating model parameterizations and gaining insights into their behavior may prove useful, provided that suitable adaptations are made for implementation in climate GCMs. This method entails the generation of short-range weather forecasts by a realistically initialized climate GCM, and the application of six-hourly NWP analyses and observations of parameterized variables to evaluate these forecasts. The behavior of the parameterizations in such a weather-forecasting framework can provide insights on how these schemes might be improved, and modified parameterizations then can be tested in the same framework. In order to further this method for evaluating and analyzing parameterizations in climate GCMs, the U.S. Department of Energy is funding a joint venture of its Climate Change Prediction Program (CCPP) and Atmospheric Radiation Measurement (ARM) Program: the CCPP-ARM Parameterization Testbed (CAPT). This article elaborates the scientific rationale for CAPT, discusses technical aspects of its methodology, and presents examples of its implementation in a representative climate GCM.

  8. [Research on greenhouse-gas-induced climate change

    Energy Technology Data Exchange (ETDEWEB)

    Schlesinger, M.

    1995-12-31

    This climate research focuses on the following topics: model development and testing; climate simulations and analyses; analyses of observed climate; development of analysis methods; global warming: physics, economics and policy; and participation in international research efforts. Also summarized are six projects that are proposed for the next five years.

  9. Numerical simulation of drifting sand

    OpenAIRE

    Alhajraf, Salem

    2000-01-01

    Two-phase flows are involved in many industrial and natural flow phenomena varying from as specific as the transport of crude oil in pipelines to as general as the dispersion of pollutants in the atmosphere. Numerical modelling based on Computational Fluid Dynamics (CFD), has attracted the attention of scientists and engineers from a wide range of backgrounds over recent decades during which these models have been extensively developed, analysed and applied to many practical...

  10. Numerical algorithms in secondary creep

    International Nuclear Information System (INIS)

    The problem of stationary creep is presented as well as its variational formulation, when weak constraints are established, capable of assuring one single solution. A second, so-called elasto-creep problem, is further analysed, together with its variational formulation. It is shown that its stationary solution coincides with that of the stationary creep and the advantages of this formulation with respect to the former one is emphasized. Some numerical applications showing the efficiency of the method propesed are finally presented

  11. Climate change

    International Nuclear Information System (INIS)

    Based on contributions on 120 French and foreign scientists representing different disciplines (mathematics, physics, mechanics, chemistry, biology, medicine, and so on), this report proposes an overview of the scientific knowledge and debate about climate change. It discusses the various indicators of climate evolution (temperatures, ice surfaces, sea level, biological indicators) and the various factors which may contribute to climate evolution (greenhouse gases, solar radiation). It also comments climate evolutions in the past as they can be investigated through some geological, thermal or geochemical indicators. Then, the authors describe and discuss the various climate mechanisms: solar activity, oceans, ice caps, greenhouse gases. In a third part, the authors discuss the different types of climate models which differ by the way they describe processes, and the current validation process for these models

  12. Climate Change

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn; Hansen, Ernst Jan de Place

    2011-01-01

    and evaluated in a Danish context. The uncertainty of the scenarios leaves major challenges that, if not addressed and taken into account in building design, will grow far more serious as climate change progresses. Cases implemented in the Danish building stock illustrate adaptation to climate change...... and illustrate how building design can include mitigating measures to counteract climate change. Cases studied were individual buildings as well as the urban environment. Furthermore the paper describes some of the issues that must be addressed, as the building sector is investing in measures to adapt to climate......This paper presents the effects of climate change relevant for Denmark, including the change in mean year values as well as the extent of maximum and minimum extremes. Described by the Intergovernmental Panel on Climate Change, the assumptions that the scenarios are based on were outlined...

  13. Climate Change

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn; Hansen, Ernst Jan de Place

    2011-01-01

    This paper presents the effects of climate change relevant for Denmark, including the change in mean year values as well as the extent of maximum and minimum extremes. Described by the Intergovernmental Panel on Climate Change, the assumptions that the scenarios are based on were outlined...... and evaluated in a Danish context. The uncertainty of the scenarios leaves major challenges that, if not addressed and taken into account in building design, will grow far more serious as climate change progresses. Cases implemented in the Danish building stock illustrate adaptation to climate change...... and illustrate how building design can include mitigating measures to counteract climate change. Cases studied were individual buildings as well as the urban environment. Furthermore the paper describes some of the issues that must be addressed, as the building sector is investing in measures to adapt to climate...

  14. Climate Research

    OpenAIRE

    Hamann, Ilse; Meier zu Verl, Christian; Horstmann, Wolfram

    2011-01-01

    The findings described in the following sections of this chapter are to a large extent based on an analysis of documents available to me at the institution where I work, i.e. in the Data Management department (DM) of the German Climate Computing Centre (DKRZ, Deutsches Klimarechenzentrum), or are part of websites of other institutions in the climate research community. Additional information about aspects of the research infrastructure in climate science comes from what I could glean from the...

  15. Sproglig Metode og Analyse

    DEFF Research Database (Denmark)

    le Fevre Jakobsen, Bjarne

    Publikationen indeholder øvematerialer, tekster, powerpointpræsentationer og handouts til undervisningsfaget Sproglig Metode og Analyse på BA og tilvalg i Dansk/Nordisk 2010-2011......Publikationen indeholder øvematerialer, tekster, powerpointpræsentationer og handouts til undervisningsfaget Sproglig Metode og Analyse på BA og tilvalg i Dansk/Nordisk 2010-2011...

  16. Stochastic Climate Theory and Modelling

    CERN Document Server

    Franzke, Christian L E; Berner, Judith; Williams, Paul D; Lucarini, Valerio

    2014-01-01

    Stochastic methods are a crucial area in contemporary climate research and are increasingly being used in comprehensive weather and climate prediction models as well as reduced order climate models. Stochastic methods are used as subgrid-scale parameterizations as well as for model error representation, uncertainty quantification, data assimilation and ensemble prediction. The need to use stochastic approaches in weather and climate models arises because we still cannot resolve all necessary processes and scales in comprehensive numerical weather and climate prediction models. In many practical applications one is mainly interested in the largest and potentially predictable scales and not necessarily in the small and fast scales. For instance, reduced order models can simulate and predict large scale modes. Statistical mechanics and dynamical systems theory suggest that in reduced order models the impact of unresolved degrees of freedom can be represented by suitable combinations of deterministic and stochast...

  17. Numerical Integration with Derivatives

    Institute of Scientific and Technical Information of China (English)

    Hu Cheng

    2006-01-01

    A new formula with derivatives for numerical integration was presented. Based on this formula and the Richardson extrapolation process, a numerical integration method was established. It can converge faster than the Romberg's. With the same accuracy, the computation of the new numerical integration with derivatives is only half of that of Romberg's numerical integration.

  18. Climate Certainties and Uncertainties

    International Nuclear Information System (INIS)

    In issue 380 of Futuribles in December 2011, Antonin Pottier analysed in detail the workings of what is today termed 'climate scepticism' - namely the propensity of certain individuals to contest the reality of climate change on the basis of pseudo-scientific arguments. He emphasized particularly that what fuels the debate on climate change is, largely, the degree of uncertainty inherent in the consequences to be anticipated from observation of the facts, not the description of the facts itself. In his view, the main aim of climate sceptics is to block the political measures for combating climate change. However, since they do not admit to this political posture, they choose instead to deny the scientific reality. This month, Futuribles complements this socio-psychological analysis of climate-sceptical discourse with an - in this case, wholly scientific - analysis of what we know (or do not know) about climate change on our planet. Pierre Morel gives a detailed account of the state of our knowledge in the climate field and what we are able to predict in the medium/long-term. After reminding us of the influence of atmospheric meteorological processes on the climate, he specifies the extent of global warming observed since 1850 and the main origin of that warming, as revealed by the current state of knowledge: the increase in the concentration of greenhouse gases. He then describes the changes in meteorological regimes (showing also the limits of climate simulation models), the modifications of hydrological regimes, and also the prospects for rises in sea levels. He also specifies the mechanisms that may potentially amplify all these phenomena and the climate disasters that might ensue. Lastly, he shows what are the scientific data that cannot be disregarded, the consequences of which are now inescapable (melting of the ice-caps, rises in sea level etc.), the only remaining uncertainty in this connection being the date at which these things will happen. 'In this

  19. Climate variability and climate change

    International Nuclear Information System (INIS)

    Changes of variability with climate change are likely to have a substantial impact on vegetation and society, rivaling the importance of changes in the mean values themselves. A variety of paleoclimate and future climate simulations performed with the GISS global climate model is used to assess how the variabilities of temperature and precipitation are altered as climate warms or cools. In general, as climate warms, temperature variability decreases due to reductions in the latitudinal temperature gradient and precipitation variability increases together with the intensity of the hydrologic cycle. If future climate projections are accurate, the reduction in temperature variability will be minimized by the rapid change in mean temperatures, but the hydrologic variability will be amplified by increased evapotranspiration. Greater hydrologic variability would appear to pose a potentially severe problem for the next century. 19 refs.; 3 figs.; 2 tabs

  20. Climate variability and climate change

    International Nuclear Information System (INIS)

    Changes of variability with climate change are likely to have a substantial impact on vegetation and society, rivaling the importance of changes in the mean values themselves. A variety of paleoclimate and future climate simulations performed with the GISS global climate model is used to assess how the variabilities of temperature and precipitation are altered as climate warms or cools. In general, as climate warms, temperature variability decreases due to reductions in the latitudinal temperature gradient and precipitation variability increases together with the intensity of the hydrologic cycle. If future climate projections are accurate, the reduction in temperature variability will be minimized by the rapid change in mean temperatures, but the hydrologic variability will be amplified by increased evapotranspiration. Greater hydrologic variability would appear to pose a potentially severe problem for the next century

  1. Etude Climat no. 37 '10 lessons from 10 years of the CDM'

    International Nuclear Information System (INIS)

    Among the publications of CDC Climat Research, 'Climate Reports' offer in-depth analyses on a given subject. This issue addresses the following points: The Clean Development Mechanism (CDM) is the first and by far the largest carbon offset instrument in the world. To date, it is the only market based on an environmental commodity which managed to attract several billions of euros of private capital on an annual basis. Being the first-of-a-kind climate change mitigation instrument, the CDM followed a 'learning by doing' pattern undergoing numerous reforms throughout its more than 10-year history. Although the post-2012 fate of the mechanism remains uncertain, one should not 'throw out the baby with the bath water' as the lessons from the CDM experience may be useful not only for the CDM reform but also for new market instruments

  2. iClimate: a climate data and analysis portal

    Science.gov (United States)

    Goodman, P. J.; Russell, J. L.; Merchant, N.; Miller, S. J.; Juneja, A.

    2015-12-01

    We will describe a new climate data and analysis portal called iClimate that facilitates direct comparisons between available climate observations and climate simulations. Modeled after the successful iPlant Collaborative Discovery Environment (www.iplantcollaborative.org) that allows plant scientists to trade and share environmental, physiological and genetic data and analyses, iClimate provides an easy-to-use platform for large-scale climate research, including the storage, sharing, automated preprocessing, analysis and high-end visualization of large and often disparate observational and model datasets. iClimate will promote data exploration and scientific discovery by providing: efficient and high-speed transfer of data from nodes around the globe (e.g. PCMDI and NASA); standardized and customized data/model metrics; efficient subsampling of datasets based on temporal period, geographical region or variable; and collaboration tools for sharing data, workflows, analysis results, and data visualizations with collaborators or with the community at large. We will present iClimate's capabilities, and demonstrate how it will simplify and enhance the ability to do basic or cutting-edge climate research by professionals, laypeople and students.

  3. Climate Controlled?

    Science.gov (United States)

    Harney, John O.

    2014-01-01

    More than 250 higher education leaders from campuses across the U.S. met last week in Boston for the 2014 Presidential Summit on Climate Leadership. The summit was organized by Second Nature, the supporting organization for the American College & University Presidents' Climate Commitment (ACUPCC). Almost 700 colleges and universities have…

  4. Numerical Simulation of Maize Yield Variation in Northeast China Under B2 Climate Change Scenario%SRES B2气候情景下东北玉米产量变化数值模拟

    Institute of Scientific and Technical Information of China (English)

    袁东敏; 尹志聪; 郭建平

    2014-01-01

    采用区域气候模式 PRECIS 与东北玉米模拟模型相耦合的方法,模拟了基准气候(BS,1961-1990年)、B2气候情景下考虑和不考虑 CO2直接影响(肥效作用)未来40年(2011-2050年)我国东北玉米生育期和产量的变化状况。结果表明:不考虑 CO2直接影响时,未来40年的平均变化情况以减产为主,幅度和熟性密切相关。在松嫩平原部分地区减产幅度最大,超过20%,但21世纪20年代的10年间东北玉米减产面积小,大部分地区表现为20%以内的增产。不考虑 CO2直接影响,玉米产量变化是由气象条件变化引起的,温度过高和降水减少是玉米减产的主要原因;CO2直接影响对玉米产量的补偿效应不可忽视。与不考虑 CO2直接影响的情况相比,未来40年平均的产量变化地理分布形势相似,但产量变化的幅度减小,减产幅度达到10%以上的范围缩小。研究气候变化对东北玉米产量的影响时,必须同时考虑 CO2肥效作用和气象条件的变化,在 B2情景下未来40年内,各年代东北玉米生育期变化的地理分布相对比较稳定,和玉米熟性关系紧密。%In order to assess the variation of maize growth due to climate change,the maize yield model is upgra-ded and coupled with a regional climate model named PRECIS.The maize growth period and yield in Northeast China are simulated both under baseline (1961 -1990)and B2 climate change scenario (2011 -2050).The variations over the next 40 years are predicted by considering and not considering CO2 fertilizer efficiency (direct influence)separately.A direct influence module of CO2 is added into the maize growth model to make concentration of CO2 as an input variable.The upgraded model can simulate the yield and the increase of C4 crop,especially maize,with different concentration of CO2 .And results fit the field ex-periments well.Furthermore,this model could distinguish fertilizer

  5. Does climate directly influence NPP globally?

    Science.gov (United States)

    Chu, Chengjin; Bartlett, Megan; Wang, Youshi; He, Fangliang; Weiner, Jacob; Chave, Jérôme; Sack, Lawren

    2016-01-01

    The need for rigorous analyses of climate impacts has never been more crucial. Current textbooks state that climate directly influences ecosystem annual net primary productivity (NPP), emphasizing the urgent need to monitor the impacts of climate change. A recent paper challenged this consensus, arguing, based on an analysis of NPP for 1247 woody plant communities across global climate gradients, that temperature and precipitation have negligible direct effects on NPP and only perhaps have indirect effects by constraining total stand biomass (Mtot ) and stand age (a). The authors of that study concluded that the length of the growing season (lgs ) might have a minor influence on NPP, an effect they considered not to be directly related to climate. In this article, we describe flaws that affected that study's conclusions and present novel analyses to disentangle the effects of stand variables and climate in determining NPP. We re-analyzed the same database to partition the direct and indirect effects of climate on NPP, using three approaches: maximum-likelihood model selection, independent-effects analysis, and structural equation modeling. These new analyses showed that about half of the global variation in NPP could be explained by Mtot combined with climate variables and supported strong and direct influences of climate independently of Mtot , both for NPP and for net biomass change averaged across the known lifetime of the stands (ABC = average biomass change). We show that lgs is an important climate variable, intrinsically correlated with, and contributing to mean annual temperature and precipitation (Tann and Pann ), all important climatic drivers of NPP. Our analyses provide guidance for statistical and mechanistic analyses of climate drivers of ecosystem processes for predictive modeling and provide novel evidence supporting the strong, direct role of climate in determining vegetation productivity at the global scale.

  6. Climate change and amphibians

    Directory of Open Access Journals (Sweden)

    Corn, P. S.

    2005-01-01

    Full Text Available Amphibian life histories are exceedingly sensitive to temperature and precipitation, and there is good evidence that recent climate change has already resulted in a shift to breeding earlier in the year for some species. There are also suggestions that the recent increase in the occurrence of El Niño events has caused declines of anurans in Central America and is linked to elevated mortality of amphibian embryos in the northwestern United States. However, evidence linking amphibian declines in Central America to climate relies solely on correlations, and the mechanisms underlying the declines are not understood. Connections between embryo mortality and declines in abundance have not been demonstrated. Analyses of existing data have generally failed to find a link between climate and amphibian declines. It is likely, however, that future climate change will cause further declines of some amphibian species. Reduced soil moisture could reduce prey species and eliminate habitat. Reduced snowfall and increased summer evaporation could have dramatic effects on the duration or occurrence of seasonal wetlands, which are primary habitat for many species of amphibians. Climate change may be a relatively minor cause of current amphibian declines, but it may be the biggest future challenge to the persistence of many species

  7. Parameter sensitivity of climate models and climate driven ecological systems

    NARCIS (Netherlands)

    Moolenaar, H.E.

    2006-01-01

    Uncertainty in the outcome of numerical models of physical and biological processes, such as the climate and ecological systems, is widely recognized. One contributing factor is uncertainty in model parameters. Because of this uncertainty, a range of model outcomes is usually given. This might obstr

  8. Likely Ranges of Climate Change in Bolivia

    NARCIS (Netherlands)

    Seiler, C.; Hutjes, R.W.A.; Kabat, P.

    2013-01-01

    Bolivia is facing numerous climate-related threats, ranging from water scarcity due to rapidly retreating glaciers in the Andes to a partial loss of the Amazon forest in the lowlands. To assess what changes in climate may be expected in the future, 35 global circulation models (GCMs) from the third

  9. Climate variability and climate change vulnerability and adaptation. Workshop summary

    International Nuclear Information System (INIS)

    Representatives from fifteen countries met in Prague, Czech Republic, on September 11-15, 1995, to share results from the analysis of vulnerability and adaptation to global climate change. The workshop focused on the issues of global climate change and its impacts on various sectors of a national economy. The U.N. Framework Convention on Climate Change (FCCC), which has been signed by more than 150 governments worldwide, calls on signatory parties to develop and communicate measures they are implementing to respond to global climate change. An analysis of a country's vulnerability to changes in the climate helps it identify suitable adaptation measures. These analyses are designed to determine the extent of the impacts of global climate change on sensitive sectors such as agricultural crops, forests, grasslands and livestock, water resources, and coastal areas. Once it is determined how vulnerable a country may be to climate change, it is possible to identify adaptation measures for ameliorating some or all of the effects.The objectives of the vulnerability and adaptation workshop were to: The objectives of the vulnerability and adaptation workshop were to: Provide an opportunity for countries to describe their study results; Encourage countries to learn from the experience of the more complete assessments and adjust their studies accordingly; Identify issues and analyses that require further investigation; and Summarize results and experiences for governmental and intergovernmental organizations

  10. Applied climate-change analysis: the climate wizard tool.

    Directory of Open Access Journals (Sweden)

    Evan H Girvetz

    Full Text Available BACKGROUND: Although the message of "global climate change" is catalyzing international action, it is local and regional changes that directly affect people and ecosystems and are of immediate concern to scientists, managers, and policy makers. A major barrier preventing informed climate-change adaptation planning is the difficulty accessing, analyzing, and interpreting climate-change information. To address this problem, we developed a powerful, yet easy to use, web-based tool called Climate Wizard (http://ClimateWizard.org that provides non-climate specialists with simple analyses and innovative graphical depictions for conveying how climate has and is projected to change within specific geographic areas throughout the world. METHODOLOGY/PRINCIPAL FINDINGS: To demonstrate the Climate Wizard, we explored historic trends and future departures (anomalies in temperature and precipitation globally, and within specific latitudinal zones and countries. We found the greatest temperature increases during 1951-2002 occurred in northern hemisphere countries (especially during January-April, but the latitude of greatest temperature change varied throughout the year, sinusoidally ranging from approximately 50 degrees N during February-March to 10 degrees N during August-September. Precipitation decreases occurred most commonly in countries between 0-20 degrees N, and increases mostly occurred outside of this latitudinal region. Similarly, a quantile ensemble analysis based on projections from 16 General Circulation Models (GCMs for 2070-2099 identified the median projected change within countries, which showed both latitudinal and regional patterns in projected temperature and precipitation change. CONCLUSIONS/SIGNIFICANCE: The results of these analyses are consistent with those reported by the Intergovernmental Panel on Climate Change, but at the same time, they provide examples of how Climate Wizard can be used to explore regionally- and temporally

  11. Climate change and climate policy

    International Nuclear Information System (INIS)

    The climate issue is a great political and scientific challenge for several reasons: (1) There are many uncertain aspects of the climate problem, such as future emission of climate gases, the response of the climate system upon these gases, and the effects of climate changes. (2) It is probable, however, that anthropogenic emission of climate gases, deforestation etc. will cause noticeable climate changes in the future. This might be observed as increased frequency of extreme weather situations. This appears to be a greater threat than a gradual increase of temperature and precipitation. (3) Since the climate system is large and react only relatively slowly on changes in for instance the emission of climate gases, the climate problem can only be solved by means of long-term measures. (4) The climate changes may be irreversible. A rational short-term strategy is to ensure maximum flexibility, which can be done by ''slowing down'' (curtailing emissions) and by avoiding irreversible actions as much as possible. The long-term challenge is to develop an economically responsible alternative to the present fossil-based energy system that permits carbon-efficient technologies to compete on price with coal and unconventional oil and gas. Norway is in a special position by being a large exporter of fossil fuel and at the same time wanting to appear responsible in environmental matters. This combination may incur considerable expenses upon Norway and it is therefore important that environmental commitments like the Kyoto agreement can be honoured to the lowest possible cost. The costs can be minimized by: (1) minimizing the measure costs in Norway, (2) working to make the international quota price as low as possible, and (3) reducing the loss of petroleum income as much as possible. This report describes the earth's climate history, the forces behind climatic changes and what the prospects for the future look like. It also reviews what is being done to curtail the emission of

  12. From climate assessment to climate services

    OpenAIRE

    Visbeck, Martin

    2008-01-01

    The Intergovernmental Panel for Climate Change has convinced the public that climate change is real. To tackle it, the panel needs complementary climate services that provide continuous climate information for all regions and the globe.

  13. Climatic change

    International Nuclear Information System (INIS)

    This book proposes both a scientific and societal approach of a phenomenon which is today the object of lot of debates. Climates perception is illustrated with examples taken in various modern civilizations and in the history of mankind. The Sahara example illustrates the notion of climate evolution. The last chapters are devoted to forecasting and scenarios for the future, taking into account the share of uncertainty. The controversies generated by these forecasts and the Kyoto protocol stakes demonstrate the tight links between the scientific, economical and political aspects in climatic change debates. (J.S.)

  14. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove;

    2007-01-01

    The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  15. State Wildlife Action Plans as Tools for Adapting to a Continuously Changing Climate

    Science.gov (United States)

    Metivier, D. W.; Yocum, H.; Ray, A. J.

    2015-12-01

    Public land management plans are potentially powerful policies for building sustainability and adaptive capacity. Land managers are recognizing the need to respond to numerous climate change impacts on natural and human systems. For the first time, in 2015, the federal government required each state to incorporate climate change into their State Wildlife Action Plans (SWAP) as a condition for funding. As important land management tools, SWAPs have the potential to guide state agencies in shaping and implementing practices for climate change adaptation. Intended to be revised every ten years, SWAPs can change as conditions and understanding of climate change evolves. This study asks what practices are states using to integrate climate change, and how does this vary between states? To answer this question, we conducted a broad analysis among seven states (CO, MT, NE, ND, SD, UT, WY) and a more in-depth analysis of four states (CO, ND, SD, WY). We use seven key factors that represent best practices for incorporating climate change identified in the literature. These best practices are species prioritization, key habitats, threats, monitoring, partnerships and participation, identification of management options, and implementation of management options. The in-depth analysis focuses on how states are using climate change information for specific habitats addressed in the plans. We find that states are integrating climate change in many different ways, showing varying degrees of sophistication and preparedness. We summarize different practices and highlight opportunities to improve the effectiveness of plans through: communication tools across state lines and stakeholders, explicit targeting of key habitats, enforcement and monitoring progress and success, and conducting vulnerability analyses that incorporate topics beyond climate and include other drivers, trajectories, and implications of historic and future land-use change.

  16. Report sensory analyses veal

    OpenAIRE

    Veldman, M.; Schelvis-Smit, A.A.M.

    2005-01-01

    On behalf of a client of Animal Sciences Group, different varieties of veal were analyzed by both instrumental and sensory analyses. The sensory evaluation was performed with a sensory analytical panel in the period of 13th of May and 31st of May, 2005. The three varieties of veal were: young bull, pink veal and white veal. The sensory descriptive analyses show that the three groups Young bulls, pink veal and white veal, differ significantly in red colour for the raw meat as well as the baked...

  17. Climate catastrophes

    Science.gov (United States)

    Budyko, Mikhail

    1999-05-01

    Climate catastrophes, which many times occurred in the geological past, caused the extinction of large or small populations of animals and plants. Changes in the terrestrial and marine biota caused by the catastrophic climate changes undoubtedly resulted in considerable fluctuations in global carbon cycle and atmospheric gas composition. Primarily, carbon dioxide and other greenhouse gas contents were affected. The study of these catastrophes allows a conclusion that climate system is very sensitive to relatively small changes in climate-forcing factors (transparency of the atmosphere, changes in large glaciations, etc.). It is important to take this conclusion into account while estimating the possible consequences of now occurring anthropogenic warming caused by the increase in greenhouse gas concentration in the atmosphere.

  18. Climate Reconstructions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Paleoclimatology Program archives reconstructions of past climatic conditions derived from paleoclimate proxies, in addition to the Program's large...

  19. Climate engineering

    OpenAIRE

    Platt, Ulrich

    2014-01-01

    Es klingt wie eine Mischung aus Größenwahn und Science Fiction: Wissenschaftler wollen das Klima mit Hightechverfahren beeinflussen. "Climate engineering" heißt der Fachbegriff. Natürlich geht es dabei nicht um den verregneten Sommer, sondern um den globalen Klimawandel. Campus-Reporter Nils Birschmann hat sich bei den Umweltforschern der Uni Heidelberg umgehört, ob was dran ist am "climate engineering". Der Beitrag erschien in der Sendereihe "Campus-Report" - einer Beitragsreihe, in ...

  20. Assessing Elementary Science Methods Students' Understanding about Global Climate Change

    Science.gov (United States)

    Lambert, Julie L.; Lindgren, Joan; Bleicher, Robert

    2012-01-01

    Global climate change, referred to as climate change in this paper, has become an important planetary issue, and given that K-12 students have numerous alternative conceptions or lack of prior knowledge, it is critical that teachers have an understanding of the fundamental science underlying climate change. Teachers need to understand the natural…

  1. Validation of two high‐resolution climate simulations over Scandinavia

    DEFF Research Database (Denmark)

    Mayer, Stephanie; Maule, Cathrine Fox; Sobolowski, Stefan;

    2014-01-01

    Before running climate projections with numerical models it is important to validate their performance under present climate conditions. Within the RiskChange project two high‐resolution regional climate models were run as a perfect boundary experiment over Scandinavia. The simulations are valida...

  2. Meta-analyses

    NARCIS (Netherlands)

    Hendriks, M.A.; Luyten, J.W.; Scheerens, J.; Sleegers, P.J.C.; Scheerens, J.

    2014-01-01

    In this chapter results of a research synthesis and quantitative meta-analyses of three facets of time effects in education are presented, namely time at school during regular lesson hours, homework, and extended learning time. The number of studies for these three facets of time that could be used

  3. Probabilistic safety analyses (PSA)

    International Nuclear Information System (INIS)

    The guide shows how the probabilistic safety analyses (PSA) are used in the design, construction and operation of light water reactor plants in order for their part to ensure that the safety of the plant is good enough in all plant operational states

  4. Wavelet Analyses and Applications

    Science.gov (United States)

    Bordeianu, Cristian C.; Landau, Rubin H.; Paez, Manuel J.

    2009-01-01

    It is shown how a modern extension of Fourier analysis known as wavelet analysis is applied to signals containing multiscale information. First, a continuous wavelet transform is used to analyse the spectrum of a nonstationary signal (one whose form changes in time). The spectral analysis of such a signal gives the strength of the signal in each…

  5. Report sensory analyses veal

    NARCIS (Netherlands)

    Veldman, M.; Schelvis-Smit, A.A.M.

    2005-01-01

    On behalf of a client of Animal Sciences Group, different varieties of veal were analyzed by both instrumental and sensory analyses. The sensory evaluation was performed with a sensory analytical panel in the period of 13th of May and 31st of May, 2005. The three varieties of veal were: young bull,

  6. Deactivations during the numerical processing

    Institute of Scientific and Technical Information of China (English)

    FENG HongBo; ZHANG Ye; TANG YiYuan; JIN Jing; DONG Feng; FENG ShiGang; ZHANG WuTian

    2007-01-01

    Deactivation has been encountered frequently in functional brain imaging researches. However,the deactivations during the numerical processing have not been reported yet. In this study,the functional magnetic resonance imaging (fMRI) was employed to investigate the pattern of the deactivation in the brain of 15 healthy subjects during the numerical addition task. Analyses revealed significant deactivations in several brain regions,including the posterior cingulate,precuneus,anterior cingulate and prefrontal cortex. Especially,we found notable deactivation in bilateral insula. Accounting for the cognitive functions of these regions participating in a combinated way,we discuss their contributions in sustaining the brain activity during conscious resting state,and indicate that the insula is an important area of gathering auditory information from the external world.

  7. Changing climate, changing frames

    International Nuclear Information System (INIS)

    Highlights: ► We show development of flood policy frames in context of climate change attention. ► Rising attention on climate change influences traditional flood policy framing. ► The new framing employs global-scale scientific climate change knowledge. ► With declining attention, framing disregards climate change, using local knowledge. ► We conclude that frames function as sensemaking devices selectively using knowledge. -- Abstract: Water management and particularly flood defence have a long history of collective action in low-lying countries like the Netherlands. The uncertain but potentially severe impacts of the recent climate change issue (e.g. sea level rise, extreme river discharges, salinisation) amplify the wicked and controversial character of flood safety policy issues. Policy proposals in this area generally involve drastic infrastructural works and long-term investments. They face the difficult challenge of framing problems and solutions in a publicly acceptable manner in ever changing circumstances. In this paper, we analyse and compare (1) how three key policy proposals publicly frame the flood safety issue, (2) the knowledge referred to in the framing and (3) how these frames are rhetorically connected or disconnected as statements in a long-term conversation. We find that (1) framings of policy proposals differ in the way they depict the importance of climate change, the relevant timeframe and the appropriate governance mode; (2) knowledge is selectively mobilised to underpin the different frames and (3) the frames about these proposals position themselves against the background of the previous proposals through rhetorical connections and disconnections. Finally, we discuss how this analysis hints at the importance of processes of powering and puzzling that lead to particular framings towards the public at different historical junctures

  8. Universal Numeric Segmented Display

    CERN Document Server

    Azad, Md Abul kalam; Kamruzzaman, S M

    2010-01-01

    Segmentation display plays a vital role to display numerals. But in today's world matrix display is also used in displaying numerals. Because numerals has lots of curve edges which is better supported by matrix display. But as matrix display is costly and complex to implement and also needs more memory, segment display is generally used to display numerals. But as there is yet no proposed compact display architecture to display multiple language numerals at a time, this paper proposes uniform display architecture to display multiple language digits and general mathematical expressions with higher accuracy and simplicity by using a 18-segment display, which is an improvement over the 16 segment display.

  9. Projection of future climate changes

    International Nuclear Information System (INIS)

    Climate models provide the opportunity to anticipate how the climate system may change due to anthropogenic activities during the 21. century. Studies are based on numerical simulations that explore the evolution of the mean climate and its variability according to different socio-economic scenarios. We present a selection of results from phase 5 of the Climate model intercomparison project (CMIP5) with an illustrative focus on the two French models that participated to this exercise. We describe the effects of human perturbations upon surface temperature, precipitation, the cryo-sphere, but also extreme weather events and the carbon cycle. Results show a number of robust features, on the amplitude and geographical patterns of the expected changes and on the processes at play in these changes. They also show the limitations of such a prospective exercise and persistent uncertainties on some key aspects. (authors)

  10. Climate and isotopic tracers

    International Nuclear Information System (INIS)

    The applications of natural radioactivity and isotopic measurements in the sciences concerning Earth and its atmosphere, are numerous: carbon 14 dating with the Tandetron apparatus at the Cea, measurement of oxygen 18 in coral or sediment limestone for the determination of ocean temperature and salinity, carbon 14 dating of corals for the determination of sea level variations, deuterium content in polar ice-cap leads to temperature variations determination; isotopic measurements also enable the determination of present climate features such as global warming, oceanic general circulation

  11. Climate Mobile: A Climate Education App For Everyone

    Science.gov (United States)

    Yunck, T. P.

    2011-12-01

    There exists a vast and energetic community of non-scientists concerned about climate change and engaged in exploring how they can contribute to our collective response. There are also many, equally energetic, who question the scientific consensus on climate change. To professionals who follow the debates it is plain that few non-scientists possess up-to-date climate information, or the means to make meaningful use of such information as can be found scattered across the internet. To remedy this GeoOptics Inc. has developed, as a spinoff of NASA's "Climate Virtual Observatory," an educational iPhone app called Climate Mobile, aka "CliMate." It allows users to call up the latest information on global surface and atmospheric temperatures and trends, Arctic ice cover, weather, atmospheric CO2 concentrations, and solar activity, along with IPCC climate forecasts and tutorials on climate change, space weather, greenhouse warming, and other subjects. Two advanced tools, the Climate Analyzer and the Sensor Data Comparator, allow the citizen-scientist to explore climate data in greater depth. The Analyzer offers access to the 130-year global surface temperature data from NOAA/NCDC and NASA/GISS, and the 32-year atmospheric temperature record from the MSU and AMSU instruments on NOAA satellites. Users can examine data for the full globe, or partitioned by N/S hemisphere or land and ocean and can filter, plot and compare the data over any desired interval, using smoothing windows ranging from 1 month to 15 years. The Comparator allows users to compare atmospheric temperature data from AIRS, GPS radio occultation, and ECMWF global analyses both regionally and globally, and compute instrumental biases and sigmas under different filtering strategies to better understand the inherent properties of each. With these tools users can generate and view plots, tailor the plot characteristics, save the results, or send them to a URL or email address. To illustrate the utility of the

  12. Extreme climatic events in a changing climate: a review

    Science.gov (United States)

    Beniston, M.

    2003-04-01

    While changes in the long-term mean state of climate will have many important consequences on numerous environmental, social, and economic sectors, the most significant impacts of climatic change are likely to come about from shifts in the intensity and frequency of extreme weather events. Indeed, insurance costs resulting from extreme weather events have been steadily increasing over the last two decades, in response to both population pressures in regions that are at risk, but also because of the frequency and severity of certain forms of extremes. Regions now safe from catastrophic wind storms, heat waves, and floods could suddenly become vulnerable. The associated damage costs would consequently be extremely high. It seems appropriate, therefore, considering the environmental, human and economic costs exerted by extreme climatic events, to address the problem of whether there may be significant shifts in extremes of wind, precipitation or temperature in a changing global climate. In order to achieve these goals, the level of current scientific understanding and the availability of computational resources now enable numerical modeling techniques to be applied to this problem area. Examples will be given of particular numerical simulations of extreme events that have affected Western Europe and the alpine region in recent years. These simulations and impacts studies will be compared to observed events and trends during the 20th century, where adequate data is available to assess the manner in which certain forms of extreme events have changed, in part as a response to the global warming observed over the last 100 years.

  13. Present-day climatic equivalents of European Cenozoic climates

    Science.gov (United States)

    Utescher, Torsten; Mosbrugger, Volker; Ivanov, Dimiter; Dilcher, David L.

    2009-07-01

    Recently, continental climate evolution in Central Europe over the last 45 Ma has been reconstructed from the palaeobotanical record using a Nearest Living Relative methodology (Coexistence Approach; CA). The reconstructed climate curves document in detail the transition from almost tropical conditions in the Mid-Eocene to a temperate climate at the Pliocene/Pleistocene transition. The observed climatic shifts are primarily expressed as non-proportional changes of the different variables taken into account. In the present study a published palaeoclimate data set for a total of 42 macrofloras complemented by new calculations is used as base to analyse the climatic space in which a fossil flora existed. To define these spaces CA intervals calculated for 3 temperature (mean annual temperature, cold and warm month mean) and 3 precipitation variables (mean annual precipitation, mean monthly precipitation of the driest and of the wettest month) are combined. Using a global gridded climatology (10' resolution), this climate space is then utilized to identify Recent climate analogues with respect to the variables regarded. For 18 macrofloras climatic analogue regions with respect to 6 variables are identified on the globe. For 16 macrofloras, analogues exist when three temperature parameters and mean annual precipitation are regarded. No Recent equivalents are found in 8 cases. This corroborates the assumption of the temporary existence of non-analogue climates in the Cenozoic. As shown by multivariate statistics the observed anomalies with respect to present-day conditions basically refer to high winter temperatures. Deploying a GIS, the Recent climate analogues can be presented as sets of grid cells for each flora that can be mapped on a globe. Once identified, these regions can be merged with adequate thematic layers to assess additional proxy data for the palaeofloras. To exemplify the procedure Koeppen climate type, numbers of days with ground frost, as well as

  14. The climate myth

    International Nuclear Information System (INIS)

    The apparent consensus of opinion about the human responsibility in the climate crisis is crumbling down. This book presents a sceptical point of view about the link between global warming and the anthropic carbon dioxide emissions. Targeting his critics on some key-points, the author explains with simple words the weaknesses of some arguments, in particular the statistical ones, that have been considered as conclusive: historical reconstruction of global ambient temperatures, ice cores analysis, climate models reliability.. Behind these particular deficiencies emerges a deeper epistemological question involving the real nature of carbon-related theories. By comparing the present day climate hypothesis to other episodes of the sciences history, the author advances that we are again in presence of a new case of 'pathological science'. Finally, he calls our attention on the insidious trend of some scientifical talks which is to consider the Earth as a subject instead of an object. The importance of the political, economical and social stakes of the climate debate imposes that we give a particular attention to these analyses. (J.S.)

  15. Griechenland eine Analyse

    Directory of Open Access Journals (Sweden)

    Frank Ehrhold

    2013-01-01

    Full Text Available During the last several years Greece has been under consistent and severe economic pressure; high national debt, trade deficit, and an undefined future has led to a persistent climate of uncertainty and presents a threat to economic recovery. As a result of the near-bankruptcy of Greece in 2010, the Greek government now receives financial relief from members of the European Monetary Union (EMU and International Monetary Fund (IMF, both of the afore-mentioned parties monitoring, with the European Central Bank (ECB and European Commission, the economic transformation process and guiding the Greek economy towards international competitiveness. Yet available data proves that Greece’s economy is still shrinking-- while unemployment rates still rise, debt to GDP ratio worsens, and private investment sinks. Furthermore, there is still controversy whether Greece will remain within the monetary union or not. Is Greece’s economy better of outside the European Monetary Union?

  16. Possible future HERA analyses

    CERN Document Server

    Geiser, Achim

    2015-01-01

    A variety of possible future analyses of HERA data in the context of the HERA data preservation programme is collected, motivated, and commented. The focus is placed on possible future analyses of the existing $ep$ collider data and their physics scope. Comparisons to the original scope of the HERA programme are made, and cross references to topics also covered by other participants of the workshop are given. This includes topics on QCD, proton structure, diffraction, jets, hadronic final states, heavy flavours, electroweak physics, and the application of related theory and phenomenology topics like NNLO QCD calculations, low-x related models, nonperturbative QCD aspects, and electroweak radiative corrections. Synergies with other collider programmes are also addressed. In summary, the range of physics topics which can still be uniquely covered using the existing data is very broad and of considerable physics interest, often matching the interest of results from colliders currently in operation. Due to well-e...

  17. Statistisk analyse med SPSS

    OpenAIRE

    Linnerud, Kristin; Oklevik, Ove; Slettvold, Harald

    2004-01-01

    Dette notatet har sitt utspring i forelesninger og undervisning for 3.års studenter i økonomi og administrasjon ved høgskolen i Sogn og Fjordane. Notatet er særlig lagt opp mot undervisningen i SPSS i de to kursene ”OR 685 Marknadsanalyse og merkevarestrategi” og ”BD 616 Økonomistyring og analyse med programvare”.

  18. Volcanic Eruptions and Climate

    Science.gov (United States)

    Robock, A.

    2012-12-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  19. Biomass feedstock analyses

    Energy Technology Data Exchange (ETDEWEB)

    Wilen, C.; Moilanen, A.; Kurkela, E. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1996-12-31

    The overall objectives of the project `Feasibility of electricity production from biomass by pressurized gasification systems` within the EC Research Programme JOULE II were to evaluate the potential of advanced power production systems based on biomass gasification and to study the technical and economic feasibility of these new processes with different type of biomass feed stocks. This report was prepared as part of this R and D project. The objectives of this task were to perform fuel analyses of potential woody and herbaceous biomasses with specific regard to the gasification properties of the selected feed stocks. The analyses of 15 Scandinavian and European biomass feed stock included density, proximate and ultimate analyses, trace compounds, ash composition and fusion behaviour in oxidizing and reducing atmospheres. The wood-derived fuels, such as whole-tree chips, forest residues, bark and to some extent willow, can be expected to have good gasification properties. Difficulties caused by ash fusion and sintering in straw combustion and gasification are generally known. The ash and alkali metal contents of the European biomasses harvested in Italy resembled those of the Nordic straws, and it is expected that they behave to a great extent as straw in gasification. Any direct relation between the ash fusion behavior (determined according to the standard method) and, for instance, the alkali metal content was not found in the laboratory determinations. A more profound characterisation of the fuels would require gasification experiments in a thermobalance and a PDU (Process development Unit) rig. (orig.) (10 refs.)

  20. Possible future HERA analyses

    Energy Technology Data Exchange (ETDEWEB)

    Geiser, Achim

    2015-12-15

    A variety of possible future analyses of HERA data in the context of the HERA data preservation programme is collected, motivated, and commented. The focus is placed on possible future analyses of the existing ep collider data and their physics scope. Comparisons to the original scope of the HERA pro- gramme are made, and cross references to topics also covered by other participants of the workshop are given. This includes topics on QCD, proton structure, diffraction, jets, hadronic final states, heavy flavours, electroweak physics, and the application of related theory and phenomenology topics like NNLO QCD calculations, low-x related models, nonperturbative QCD aspects, and electroweak radiative corrections. Synergies with other collider programmes are also addressed. In summary, the range of physics topics which can still be uniquely covered using the existing data is very broad and of considerable physics interest, often matching the interest of results from colliders currently in operation. Due to well-established data and MC sets, calibrations, and analysis procedures the manpower and expertise needed for a particular analysis is often very much smaller than that needed for an ongoing experiment. Since centrally funded manpower to carry out such analyses is not available any longer, this contribution not only targets experienced self-funded experimentalists, but also theorists and master-level students who might wish to carry out such an analysis.

  1. Modular Construction of Shape-Numeric Analyzers

    Directory of Open Access Journals (Sweden)

    Bor-Yuh Evan Chang

    2013-09-01

    Full Text Available The aim of static analysis is to infer invariants about programs that are precise enough to establish semantic properties, such as the absence of run-time errors. Broadly speaking, there are two major branches of static analysis for imperative programs. Pointer and shape analyses focus on inferring properties of pointers, dynamically-allocated memory, and recursive data structures, while numeric analyses seek to derive invariants on numeric values. Although simultaneous inference of shape-numeric invariants is often needed, this case is especially challenging and is not particularly well explored. Notably, simultaneous shape-numeric inference raises complex issues in the design of the static analyzer itself. In this paper, we study the construction of such shape-numeric, static analyzers. We set up an abstract interpretation framework that allows us to reason about simultaneous shape-numeric properties by combining shape and numeric abstractions into a modular, expressive abstract domain. Such a modular structure is highly desirable to make its formalization and implementation easier to do and get correct. To achieve this, we choose a concrete semantics that can be abstracted step-by-step, while preserving a high level of expressiveness. The structure of abstract operations (i.e., transfer, join, and comparison follows the structure of this semantics. The advantage of this construction is to divide the analyzer in modules and functors that implement abstractions of distinct features.

  2. NOVEL METHOD SOLVING NUMERICAL INSTABILITIES IN TOPOLOGY OPTIMIZATION

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Numerical instabilities are often encountered in FE solution of continuum topology optimization. The essence of the numerical instabilities is given from the inverse partial differential equation (PDE) point of view. On the basis of the strict mathematical theory, a novel method, named as window filter and multi-grid method, which solves the numerical instabilities, is proposed. Convergent analyses and a numerical example are presented.

  3. Climatic changes

    DEFF Research Database (Denmark)

    Majgaard Krarup, Jonna

    2014-01-01

    According to Cleo Paskal climatic changes are environmental changes. They are global, but their impact is local, and manifests them selves in the landscape, in our cities, in open urban spaces, and in everyday life. The landscape and open public spaces will in many cases be the sites where...... measurements to handle climatic changes will be positioned and enacted. Measurements taken are mostly adaptive or aimed to secure and protect existing values, buildings, infrastructure etc., but will in many cases also affects functions, meaning and peoples identification with the landscape and the open urban...... be addressed in order to develop and support social sustainability and identification. This paper explore and discuss how the handling of climatic changes in landscape and open urban spaces might hold a potential for them to become common goods....

  4. Temperate climate - Innovative outputs nexus

    NARCIS (Netherlands)

    Coccia, M.

    2014-01-01

    Technological change is a vital human activity that interacts with geographic factors and environment. The purpose of the study here is to analyse the relationship between geo-climate zones of the globe and technological outputs in order to detect favourable areas that spur higher technological chan

  5. Uncertainty quantification and validation of combined hydrological and macroeconomic analyses.

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Jacquelynne; Parks, Mancel Jordan; Jennings, Barbara Joan; Kaplan, Paul Garry; Brown, Theresa Jean; Conrad, Stephen Hamilton

    2010-09-01

    Changes in climate can lead to instabilities in physical and economic systems, particularly in regions with marginal resources. Global climate models indicate increasing global mean temperatures over the decades to come and uncertainty in the local to national impacts means perceived risks will drive planning decisions. Agent-based models provide one of the few ways to evaluate the potential changes in behavior in coupled social-physical systems and to quantify and compare risks. The current generation of climate impact analyses provides estimates of the economic cost of climate change for a limited set of climate scenarios that account for a small subset of the dynamics and uncertainties. To better understand the risk to national security, the next generation of risk assessment models must represent global stresses, population vulnerability to those stresses, and the uncertainty in population responses and outcomes that could have a significant impact on U.S. national security.

  6. Numerical methods using Matlab

    CERN Document Server

    Gupta, Abhishek

    2015-01-01

    Numerical Methods with MATLAB provides a highly-practical reference work to assist anyone working with numerical methods. A wide range of techniques are introduced, their merits discussed and fully working MATLAB code samples supplied to demonstrate how they can be coded and applied. Numerical methods have wide applicability across many scientific, mathematical, and engineering disciplines and are most often employed in situations where working out an exact answer to the problem by another method is impractical. Numerical Methods with MATLAB presents each topic in a concise and readable

  7. Numerical methods using Matlab

    CERN Document Server

    Lindfield, George

    2012-01-01

    Numerical Methods using MATLAB, 3e, is an extensive reference offering hundreds of useful and important numerical algorithms that can be implemented into MATLAB for a graphical interpretation to help researchers analyze a particular outcome. Many worked examples are given together with exercises and solutions to illustrate how numerical methods can be used to study problems that have applications in the biosciences, chaos, optimization, engineering and science across the board. Numerical Methods using MATLAB, 3e, is an extensive reference offering hundreds of use

  8. Advance in Application of Regional Climate Models in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; YAN Minhua; CHEN Panqin; XU Helan

    2008-01-01

    Regional climate models have become the powerful tools for simulating regional climate and its changeprocess and have been widely used in China. Using regional climate models, some research results have been obtainedon the following aspects: 1) the numerical simulation of East Asian monsoon climate, including exceptional monsoonprecipitation, summer precipitation distribution, East Asian circulation, multi-year climate average condition, summerrain belt and so on; 2) the simulation of arid climate of the western China, including thermal effect of the Qing-hai-Tibet Plateau, the plateau precipitation in the Qilian Mountains; and the impacts of greenhouse effects (CO2 dou-bling) upon climate in the western China; and 3) the simulation of the climate effect of underlying surface changes, in-cluding the effect of soil on climate formation, the influence of terrain on precipitation, the effect of regional soil deg-radation on regional climate, the effect of various underlying surfaces on regional climate, the effect of land-sea con-trast on the climate formulation, the influence of snow cover over the plateau regions on the regional climate, the effectof vegetation changes on the regional climate, etc. In the process of application of regional climate models, the prefer-ences of the models are improved so that better simulation results are gotten. At last, some suggestions are made aboutthe application of regional climate models in regional climate research in the future.

  9. Simulation of an ensemble of future climate time series with an hourly weather generator

    Science.gov (United States)

    Caporali, E.; Fatichi, S.; Ivanov, V. Y.; Kim, J.

    2010-12-01

    There is evidence that climate change is occurring in many regions of the world. The necessity of climate change predictions at the local scale and fine temporal resolution is thus warranted for hydrological, ecological, geomorphological, and agricultural applications that can provide thematic insights into the corresponding impacts. Numerous downscaling techniques have been proposed to bridge the gap between the spatial scales adopted in General Circulation Models (GCM) and regional analyses. Nevertheless, the time and spatial resolutions obtained as well as the type of meteorological variables may not be sufficient for detailed studies of climate change effects at the local scales. In this context, this study presents a stochastic downscaling technique that makes use of an hourly weather generator to simulate time series of predicted future climate. Using a Bayesian approach, the downscaling procedure derives distributions of factors of change for several climate statistics from a multi-model ensemble of GCMs. Factors of change are sampled from their distributions using a Monte Carlo technique to entirely account for the probabilistic information obtained with the Bayesian multi-model ensemble. Factors of change are subsequently applied to the statistics derived from observations to re-evaluate the parameters of the weather generator. The weather generator can reproduce a wide set of climate variables and statistics over a range of temporal scales, from extremes, to the low-frequency inter-annual variability. The final result of such a procedure is the generation of an ensemble of hourly time series of meteorological variables that can be considered as representative of future climate, as inferred from GCMs. The generated ensemble of scenarios also accounts for the uncertainty derived from multiple GCMs used in downscaling. Applications of the procedure in reproducing present and future climates are presented for different locations world-wide: Tucson (AZ

  10. Organizational Climate for Successful Aging.

    Science.gov (United States)

    Zacher, Hannes; Yang, Jie

    2016-01-01

    Research on successful aging at work has neglected contextual resources such as organizational climate, which refers to employees' shared perceptions of their work environment. We introduce the construct of organizational climate for successful aging (OCSA) and examine it as a buffer of the negative relationship between employee age and focus on opportunities (i.e., beliefs about future goals and possibilities at work). Moreover, we expected that focus on opportunities, in turn, positively predicts job satisfaction, organizational commitment, and motivation to continue working after official retirement age. Data came from 649 employees working in 120 companies (M age = 44 years, SD = 13). We controlled for organizational tenure, psychological climate for successful aging (i.e., individuals' perceptions), and psychological and organizational age discrimination climate. Results of multilevel analyses supported our hypotheses. Overall, our findings suggest that OCSA is an important contextual resource for successful aging at work. PMID:27458405

  11. Organizational Climate for Successful Aging.

    Science.gov (United States)

    Zacher, Hannes; Yang, Jie

    2016-01-01

    Research on successful aging at work has neglected contextual resources such as organizational climate, which refers to employees' shared perceptions of their work environment. We introduce the construct of organizational climate for successful aging (OCSA) and examine it as a buffer of the negative relationship between employee age and focus on opportunities (i.e., beliefs about future goals and possibilities at work). Moreover, we expected that focus on opportunities, in turn, positively predicts job satisfaction, organizational commitment, and motivation to continue working after official retirement age. Data came from 649 employees working in 120 companies (M age = 44 years, SD = 13). We controlled for organizational tenure, psychological climate for successful aging (i.e., individuals' perceptions), and psychological and organizational age discrimination climate. Results of multilevel analyses supported our hypotheses. Overall, our findings suggest that OCSA is an important contextual resource for successful aging at work.

  12. Digital differential analysers

    CERN Document Server

    Shilejko, A V; Higinbotham, W

    1964-01-01

    Digital Differential Analysers presents the principles, operations, design, and applications of digital differential analyzers, a machine with the ability to present initial quantities and the possibility of dividing them into separate functional units performing a number of basic mathematical operations. The book discusses the theoretical principles underlying the operation of digital differential analyzers, such as the use of the delta-modulation method and function-generator units. Digital integration methods and the classes of digital differential analyzer designs are also reviewed. The te

  13. Wavelet analyses and applications

    Energy Technology Data Exchange (ETDEWEB)

    Bordeianu, Cristian C [Faculty of Physics, University of Bucharest, Bucharest, RO 077125 (Romania); Landau, Rubin H [Department of Physics, Oregon State University, Corvallis, OR 97331 (United States); Paez, Manuel J [Department of Physics, University of Antioquia, Medellin (Colombia)], E-mail: cristian.bordeianu@brahms.fizica.unibuc.ro, E-mail: rubin@science.oregonstate.edu, E-mail: mpaez@fisica.udea.edu.co

    2009-09-15

    It is shown how a modern extension of Fourier analysis known as wavelet analysis is applied to signals containing multiscale information. First, a continuous wavelet transform is used to analyse the spectrum of a nonstationary signal (one whose form changes in time). The spectral analysis of such a signal gives the strength of the signal in each frequency as a function of time. Next, the theory is specialized to discrete values of time and frequency, and the resulting discrete wavelet transform is shown to be useful for data compression. This paper is addressed to a broad community, from undergraduate to graduate students to general physicists and to specialists in other fields than wavelets.

  14. Systemdynamisk analyse av vannkraftsystem

    OpenAIRE

    Rydning, Anja

    2007-01-01

    I denne oppgaven er det gjennomført en dynamisk analyse av vannkraftverket Fortun kraftverk. Tre fenomener er særlig vurdert i denne oppgaven: Sjaktsvingninger mellom svingesjakt og magasin, trykkstøt ved turbinen som følge av retardasjonstrykk ved endring i turbinvannføringen og reguleringsstabilitet. Sjaktsvingningene og trykkstøt beregnes analytisk ut fra kontinuitets- og bevegelsesligningen. Modeller av Fortun kraftverk er laget for å beregne trykkstøt og sjaktsvingninger. En modell e...

  15. Natural versus anthropogenic climate change: Swedish farmers' joint construction of climate perceptions.

    Science.gov (United States)

    Asplund, Therese

    2016-07-01

    While previous research into understandings of climate change has usually examined general public perceptions, this study offers an audience-specific departure point. This article analyses how Swedish farmers perceive climate change and how they jointly shape their understandings. The agricultural sector is of special interest because it both contributes to and is directly affected by climate change. Through focus group discussions with Swedish farmers, this study finds that (1) farmers relate to and understand climate change through their own experiences, (2) climate change is understood either as a natural process subject to little or no human influence or as anthropogenic and (3) various communication tools contribute to the formation of natural and anthropogenic climate change frames. The article ends by discussing frame resonance and frame clash in public understanding of climate change and by comparing potential similarities and differences in how various segments of the public make sense of climate change.

  16. Natural versus anthropogenic climate change: Swedish farmers' joint construction of climate perceptions.

    Science.gov (United States)

    Asplund, Therese

    2016-07-01

    While previous research into understandings of climate change has usually examined general public perceptions, this study offers an audience-specific departure point. This article analyses how Swedish farmers perceive climate change and how they jointly shape their understandings. The agricultural sector is of special interest because it both contributes to and is directly affected by climate change. Through focus group discussions with Swedish farmers, this study finds that (1) farmers relate to and understand climate change through their own experiences, (2) climate change is understood either as a natural process subject to little or no human influence or as anthropogenic and (3) various communication tools contribute to the formation of natural and anthropogenic climate change frames. The article ends by discussing frame resonance and frame clash in public understanding of climate change and by comparing potential similarities and differences in how various segments of the public make sense of climate change. PMID:25471349

  17. Norwegian climate research. An evaluation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-06-15

    [English] In early 2011, the Norwegian Research Council (RCN) appointed a committee to review Norwegian climate research. The aim of the evaluation was to provide a critical review of Norwegian climate research in an international perspective and to recommend measures to enhance the quality, efficiency and relevance of future climate research. The Evaluation Committee met three times: in August and December 2011, and March 2012. RCN sent an invitation to 140 research organisations to participate by delivering background information on their climate research. Based on the initial response, 48 research units were invited to submit self-assessments and 37 research units responded. These were invited to hearings during the second meeting of the Evaluation Committee in December. In our judgement, a great majority of the most active research units are covered by this evaluation report. It should be emphasised that the evaluation concerned the Norwegian landscape of climate research rather than individual scientists or research units. Bibliometric analyses and social network analyses provided additional information. We are aware of problems in making comparisons across disciplinary publishing traditions, especially with regard to the differences between the natural and social sciences and the humanities. The Evaluation Committee also reviewed a number of governmental and RCN policy documents and conducted interviews with the chairs of the NORKLIMA Programme Steering Board and the Norwegian IPY Committee, as well as with staff members of RCN. Additional information was received from hearings organised by RCN with the science communities and various stakeholders in January 2012. For the purpose of this evaluation, climate research was divided into three broad thematic areas: 1. The climate system and climate change: research on climate variability and change in order to improve our capability of understanding climate and of projecting climate change for different time

  18. Numerical Modelling of Streams

    DEFF Research Database (Denmark)

    Vestergaard, Kristian

    In recent years there has been a sharp increase in the use of numerical water quality models. Numeric water quality modeling can be divided into three steps: Hydrodynamic modeling for the determination of stream flow and water levels. Modelling of transport and dispersion of a conservative...

  19. Climate Change Impacts on the Congo Basin Region

    NARCIS (Netherlands)

    Ludwig, F.; Franssen, W.; Jans, W.W.P.; Kruijt, B.; Supit, I.

    2012-01-01

    This report presents analyses of climate change impacts in the Congo Basin on water for agriculture and hydropower, forest ecosystem functioning and carbon storage and impacts of climate variability and change on future economic development. To quantify the impacts of future climate we developed a m

  20. Numerical Transducer Modeling

    DEFF Research Database (Denmark)

    Henriquez, Vicente Cutanda

    This thesis describes the development of a numerical model of the propagation of sound waves in fluids with viscous and thermal losses, with application to the simulation of acoustic transducers, in particular condenser microphones for measurement. The theoretical basis is presented, numerical...... that are allowable in this case: linear variations, absence of flow, harmonic time variation, thermodynamical equilibrium and physical dimensions much larger than the molecular mean free path. A formulation of the BEM is also developed with an improvement designed to cope with the numerical difficulty associated...... with very close surfaces, as found in condenser microphones, where the membrane has a backplate very close behind. This improvement could be useful for many other problems where the BEM is applied. The numerical implementation that includes both viscous and thermal effects is then worked out. Some numerical...

  1. Numerical Verification of Industrial Numerical Codes

    Directory of Open Access Journals (Sweden)

    Montan Sethy

    2012-04-01

    Full Text Available Several approximations occur during a numerical simulation: physical effects mapy be discarded, continuous functions replaced by discretized ones and real numbers replaced by finite-precision representations. The use of the floating point arithmetic generates round-off errors at each arithmetical expression and some mathematical properties are lost. The aim of the numerical verification activity at EDF R&D is to study the effect of the round-off error propagation on the results of a numerical simulation. It is indeed crucial to perform a numerical verification of industrial codes such as developped at EDF R&D even more for code running in HPC environments. This paper presents some recent studies around the numerical verification at EDF R&D. Le résultat d’un code de simulation numérique subit plusieurs approximations effectuées lors de la modélisation mathématique du problème physique, de la discrétisation du modèle mathématique et de la résolution numérique en arithmétique flottante. L’utilisation de l’arithmétique flottante génère en effet des erreurs d’arrondi lors de chaque opération flottante et des propriétés mathématiques sont perdues. Il existe à EDF R&D une activité transverse de vérification numérique consistant à étudier l’effet de la propagation des erreurs d’arrondi sur les résultats des simulations. Il est en effet important de vérifier numériquement des codes industriels et ce d’autant plus s’ils sont éxécutés dans environnements de calcul haute performance. Ce papier présente des études récentes autour de la vérification numérique à EDF R&D.

  2. Uncertainty in climate science and climate policy

    OpenAIRE

    Rougier, Jonathan; Crucifix, Michel

    2014-01-01

    This essay, written by a statistician and a climate scientist, describes our view of the gap that exists between current practice in mainstream climate science, and the practical needs of policymakers charged with exploring possible interventions in the context of climate change. By `mainstream' we mean the type of climate science that dominates in universities and research centres, which we will term `academic' climate science, in contrast to `policy' climate science; aspects of this distinc...

  3. EEG analyses with SOBI.

    Energy Technology Data Exchange (ETDEWEB)

    Glickman, Matthew R.; Tang, Akaysha (University of New Mexico, Albuquerque, NM)

    2009-02-01

    The motivating vision behind Sandia's MENTOR/PAL LDRD project has been that of systems which use real-time psychophysiological data to support and enhance human performance, both individually and of groups. Relevant and significant psychophysiological data being a necessary prerequisite to such systems, this LDRD has focused on identifying and refining such signals. The project has focused in particular on EEG (electroencephalogram) data as a promising candidate signal because it (potentially) provides a broad window on brain activity with relatively low cost and logistical constraints. We report here on two analyses performed on EEG data collected in this project using the SOBI (Second Order Blind Identification) algorithm to identify two independent sources of brain activity: one in the frontal lobe and one in the occipital. The first study looks at directional influences between the two components, while the second study looks at inferring gender based upon the frontal component.

  4. Network class superposition analyses.

    Science.gov (United States)

    Pearson, Carl A B; Zeng, Chen; Simha, Rahul

    2013-01-01

    Networks are often used to understand a whole system by modeling the interactions among its pieces. Examples include biomolecules in a cell interacting to provide some primary function, or species in an environment forming a stable community. However, these interactions are often unknown; instead, the pieces' dynamic states are known, and network structure must be inferred. Because observed function may be explained by many different networks (e.g., ≈ 10(30) for the yeast cell cycle process), considering dynamics beyond this primary function means picking a single network or suitable sample: measuring over all networks exhibiting the primary function is computationally infeasible. We circumvent that obstacle by calculating the network class ensemble. We represent the ensemble by a stochastic matrix T, which is a transition-by-transition superposition of the system dynamics for each member of the class. We present concrete results for T derived from boolean time series dynamics on networks obeying the Strong Inhibition rule, by applying T to several traditional questions about network dynamics. We show that the distribution of the number of point attractors can be accurately estimated with T. We show how to generate Derrida plots based on T. We show that T-based Shannon entropy outperforms other methods at selecting experiments to further narrow the network structure. We also outline an experimental test of predictions based on T. We motivate all of these results in terms of a popular molecular biology boolean network model for the yeast cell cycle, but the methods and analyses we introduce are general. We conclude with open questions for T, for example, application to other models, computational considerations when scaling up to larger systems, and other potential analyses. PMID:23565141

  5. Climate Change: Basic Information

    Science.gov (United States)

    ... are here: EPA Home Climate Change Basic Information Climate Change: Basic Information On This Page Climate change ... We can make a difference How is the climate changing in the U.S.? Observations across the United ...

  6. Coexistence, Classroom Climate and Philosophy for Children

    Directory of Open Access Journals (Sweden)

    Gonzalo Romero Izarra

    2008-12-01

    Full Text Available In this paper we analyse the relationship between the classroom’s social climate and the general climate of society in which the school is inserted. We consider essential to start from this reflection in order to define an educational process for social transformation. Philosophy for Children is a methodological option to improve this social climate as it offers teachers and pupils a potentially transforming work that deepens into the values of human relationships for people who are concerned with what happens around them. These are the foundations for democratic relations and a positive classroom social climate.

  7. Efficient climate policies under technology and climate uncertainty

    International Nuclear Information System (INIS)

    This article explores efficient climate policies in terms of investment streams into fossil and renewable energy technologies. The investment decisions maximise social welfare while observing a probabilistic guardrail for global mean temperature rise under uncertain technology and climate parameters. Such a guardrail constitutes a chance constraint, and the resulting optimisation problem is an instance of chance constrained programming, not stochastic programming as often employed. Our analysis of a model of economic growth and endogenous technological change, MIND, suggests that stringent mitigation strategies cannot guarantee a very high probability of limiting warming to 2 oC since preindustrial time under current uncertainty about climate sensitivity and climate response time scale. Achieving the 2 oC temperature target with a probability P* of 75% requires drastic carbon dioxide emission cuts. This holds true even though we have assumed an aggressive mitigation policy on other greenhouse gases from, e.g., the agricultural sector. The emission cuts are deeper than estimated from a deterministic calculation with climate sensitivity fixed at the P* quantile of its marginal probability distribution (3.6 oC). We show that earlier and cumulatively larger investments into the renewable sector are triggered by including uncertainty in the technology and climate response time scale parameters. This comes at an additional GWP loss of 0.3%, resulting in a total loss of 0.8% GWP for observing the chance constraint. We obtained those results with a new numerical scheme to implement constrained welfare optimisation under uncertainty as a chance constrained programming problem in standard optimisation software such as GAMS. The scheme is able to incorporate multivariate non-factorial probability measures such as given by the joint distribution of climate sensitivity and response time. We demonstrate the scheme for the case of a four-dimensional parameter space capturing

  8. Climate and development

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, A.K.

    1984-01-01

    The authors review the existing knowledge on the inter-relationships between climate and patterns of development; the impact variables on water and agricultural development; and the effects of climate on human health. A case study is also given of the effect of climatic fluctuations on human population in Mesopotamia. Contents: Climate and Development; Climate and Agriculture; Climate and Water Management; Climate and Health; Effects of Climate Fluctation on Human Populations; Study of Mesopotamian Society.

  9. Uralic numerals : is the evolution of numeral system reconstructable? : (Reading new Václav Balzhek's book on numerals in Eurasia) / Vladimir Napolskich

    Index Scriptorium Estoniae

    Napolskich, Vladimir

    2003-01-01

    Rmt.: Balzhek, Václav. Numerals. Comparative-etymological analyses of numeral systems and their implications (saharan, nubian, egyptian, berber, kartvelian, ralic, altaic and indo-european languages). Brno, 1999. (Spisy Masarykovy Univerzity v Brné. Filozofická fakulta; 322). Ülevaade uurali keelte arvsõnu käsitlevast osast

  10. Uncertainty in climate science and climate policy

    CERN Document Server

    Rougier, Jonathan

    2014-01-01

    This essay, written by a statistician and a climate scientist, describes our view of the gap that exists between current practice in mainstream climate science, and the practical needs of policymakers charged with exploring possible interventions in the context of climate change. By `mainstream' we mean the type of climate science that dominates in universities and research centres, which we will term `academic' climate science, in contrast to `policy' climate science; aspects of this distinction will become clearer in what follows. In a nutshell, we do not think that academic climate science equips climate scientists to be as helpful as they might be, when involved in climate policy assessment. Partly, we attribute this to an over-investment in high resolution climate simulators, and partly to a culture that is uncomfortable with the inherently subjective nature of climate uncertainty.

  11. Numerical Experiment on the Impact of the Urbanizing on Regional Climate and Water Resources in Huanghe-Huaihe-Haihe Zone%大规模城镇化对黄淮海地区气候及水资源影响的数值试验

    Institute of Scientific and Technical Information of China (English)

    陈怀亮; 徐祥德; 李飞; 王兰宁; 杜子璇

    2012-01-01

    Numerical experiment has been carried out over HHH (Huanghe-Huaihe-Haihe) zone by using regional climate model RegCM3 for 5 years (2001-2005). The simulation has two tests, a control test and a sensitivity test on urbanizing conditions. The output results of the regional climate model are precipitation, evaporation, temperature, humidity, soil moisture, runoff, and the total water vapor con-tent. The difference value between sensitivity test and control test responds to the influence of vegetation variation on regional climate and water resources in HHH zone. The results showed that the urbanization could weaken the local wind field, decrease rainfall and water resources and make the temperature in-crease. The variations resulting in the autumn drought happen easily, the floods became more severity be- cause of the increasing of runoff in summer. The urbanization caused the decreasing of soil moisture holding capaci- ty, and stimulated the vegetation degradation greatly. Accordingly, the climate abnormity and the shortening ofwater resources in HHH zone transformed tempestuously, and led to the ecological environment deteriorating.%黄淮海地区是我国传统的农耕区,也是经济快速发展、城镇化进程快速推进的区域之一,使得该地区植被覆盖发生了明显变化。为研究城镇化对气候与水资源的影响,应用RegCM3区域气候模式,通过控制试验和敏感性试验,在保证积分时间(2001-2005年)的情况下,输出降水、蒸发、温度、湿度、土壤水分、径流、整层水汽含量等资料,利用敏感性试验和控制试验输出量的差值,来分析黄淮海地区城镇化对气候和水资源要素的影响情况。结果表明,城镇化对研究地区气候及水资源造成的影响主要表现在使局地风场减弱、降水减少、地面气温增加、空气湿度减小、水资源总量减少、土壤含水量减少和地表径流增加等方面,从而对气候和水资源造成影响。

  12. Numerical distance protection

    CERN Document Server

    Ziegler, Gerhard

    2011-01-01

    Distance protection provides the basis for network protection in transmission systems and meshed distribution systems. This book covers the fundamentals of distance protection and the special features of numerical technology. The emphasis is placed on the application of numerical distance relays in distribution and transmission systems.This book is aimed at students and engineers who wish to familiarise themselves with the subject of power system protection, as well as the experienced user, entering the area of numerical distance protection. Furthermore it serves as a reference guide for s

  13. Numerical problems in physics

    CERN Document Server

    Singh, Devraj

    2015-01-01

    Numerical Problems in Physics, Volume 1 is intended to serve the need of the students pursuing graduate and post graduate courses in universities with Physics and Materials Science as subject including those appearing in engineering, medical, and civil services entrance examinations. KEY FEATURES: * 29 chapters on Optics, Wave & Oscillations, Electromagnetic Field Theory, Solid State Physics & Modern Physics * 540 solved numerical problems of various universities and ompetitive examinations * 523 multiple choice questions for quick and clear understanding of subject matter * 567 unsolved numerical problems for grasping concepts of the various topic in Physics * 49 Figures for understanding problems and concept

  14. Climate sensitivity

    OpenAIRE

    Roy THOMPSON

    2015-01-01

    Earth has been habitable through most of its history, but the anthropogenically mediated greenhouse effect, if sufficiently strong, can threaten Earth's long-standing equability. This paper's main aim is to determine the strength of the anthropogenic greenhouse effect (the climate sensitivity) from observational data and basic physics alone, without recourse to the parameterisations of earth-system models and their inevitable uncertainties. A key finding is that the sensitivity can be constra...

  15. Climate oblige

    International Nuclear Information System (INIS)

    This file contains 15 articles discussing various aspects of the struggle against climatic change: 'greening' the industry in order to cope with the COP 21 expectations of a 2 deg C maximum warming at the end of this century; financing the transition energy policy in the poorest countries; the issues and stakes for the COP 21 conference to be held in Paris; towards an energy system with fossil fuels to be left in the ground, especially coal; emerging and developing countries could be in the future at the forefront to benefit from the renewable energy technologies; towards a 100 pc renewable France with wind and solar power; low carbon electric power (including nuclear power) is one of the best solutions against global warming; solar energy: the example of India and its 100 GW objective in 2022; the main struggle against climatic change lies in the cities and especially with the development of low-energy buildings and energy conservation systems; with de-polluted engine, connectivity and light structure technologies, the automotive sector can mix mobility and environment protection; some examples of the environmental policy underway in Grenoble city; green collective transportation systems in Sweden; application of simulation tools and satellite observations for climatic change forecasting and analysis; the importance of eco-design of manufactured products following the 'from well to wheel' and 'from cradle to grave' concepts

  16. Website-analyse

    DEFF Research Database (Denmark)

    Thorlacius, Lisbeth

    2009-01-01

    planlægning af de funktionelle og indholdsmæssige aspekter ved websites. Der findes en stor mængde teori- og metodebøger, som har specialiseret sig i de tekniske problemstillinger i forbindelse med interaktion og navigation, samt det sproglige indhold på websites. Den danske HCI (Human Computer Interaction...... hyperfunktionelle websites. Det primære ærinde for HCI-eksperterne er at udarbejde websites, som er brugervenlige. Ifølge deres direktiver skal websites være opbygget med hurtige og effektive navigations- og interaktionsstrukturer, hvor brugeren kan få sine informationer ubesværet af lange downloadingshastigheder...... eller blindgyder, når han/hun besøger sitet. Studier i design og analyse af de visuelle og æstetiske aspekter i planlægning og brug af websites har imidlertid kun i et begrænset omfang været under reflektorisk behandling. Det er baggrunden for dette kapitel, som indleder med en gennemgang af æstetikkens...

  17. Climate change, insurance, and the buildings sector: Technological synergisms between adaptation and mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Evan

    2002-11-01

    Examining the intersection of risk analysis and sustainable energy strategies reveals numerous examples of energy efficient and renewable energy technologies that offer insurance loss-prevention benefits. The growing threat of climate change provides an added motivation for the risk community to better understand this area of opportunity. While analyses of climate change mitigation typically focus on the emissions-reduction characteristics of sustainable energy technologies, less often recognized are a host of synergistic ways in which these technologies also offer adaptation benefits, e.g. making buildings more resilient to natural disasters. While there is already some relevant activity, there remain various barriers to significantly expanding these efforts. Achieving successful integration of sustainable energy considerations with risk-management objectives requires a more proactive orientation, and coordination among diverse actors and industry groups.

  18. Climate change, insurance and the building sector: technological synergisms between adaptation and mitigation

    International Nuclear Information System (INIS)

    Examining the intersection of risk analysis and sustainable energy strategies reveals numerous examples of energy-efficient and renewable energy technologies that offer insurance loss-prevention benefits. The growing threat of climate change provides an added motivation for the risk community to understand better this area of opportunity. While analyses of climate change mitigation typically focus on the emissions-reduction characteristics of sustainable energy technologies, less often recognised are a host of synergistic ways in which these technologies also offer adaptation benefits, e.g. making buildings more resilient to natural disasters. While there is already some relevant activity, there remain various barriers to expanding these efforts significantly. Achieving successful integration of sustainable energy considerations with risk-management objectives requires a more proactive orientation, and coordination among diverse actors and industry groups. (author)

  19. Introduction to numerical analysis

    CERN Document Server

    Hildebrand, F B

    1987-01-01

    Well-known, respected introduction, updated to integrate concepts and procedures associated with computers. Computation, approximation, interpolation, numerical differentiation and integration, smoothing of data, other topics in lucid presentation. Includes 150 additional problems in this edition. Bibliography.

  20. Numerical semigroups and applications

    CERN Document Server

    Assi, Abdallah

    2016-01-01

    This work presents applications of numerical semigroups in Algebraic Geometry, Number Theory, and Coding Theory. Background on numerical semigroups is presented in the first two chapters, which introduce basic notation and fundamental concepts and irreducible numerical semigroups. The focus is in particular on free semigroups, which are irreducible; semigroups associated with planar curves are of this kind. The authors also introduce semigroups associated with irreducible meromorphic series, and show how these are used in order to present the properties of planar curves. Invariants of non-unique factorizations for numerical semigroups are also studied. These invariants are computationally accessible in this setting, and thus this monograph can be used as an introduction to Factorization Theory. Since factorizations and divisibility are strongly connected, the authors show some applications to AG Codes in the final section. The book will be of value for undergraduate students (especially those at a higher leve...

  1. Advances in Numerical Methods

    CERN Document Server

    Mastorakis, Nikos E

    2009-01-01

    Features contributions that are focused on significant aspects of current numerical methods and computational mathematics. This book carries chapters that advanced methods and various variations on known techniques that can solve difficult scientific problems efficiently.

  2. Mathematical and Physical Ideas for Climate Science

    CERN Document Server

    Lucarini, Valerio; Herbert, Corentin; Pascale, Salvatore; Wouters, Jeroen

    2013-01-01

    The climate is an excellent example of a forced, dissipative system dominated by nonlinear processes and featuring non-trivial dynamics of a vast range of spatial and temporal scales. The understanding of the climate's structural and multiscale properties is crucial for the provision of a unifying picture of its dynamics an thd for the implementation of accurate and efficient numerical models. In this interdisciplinary review, we are guided by our interest in exploring the nexus between climate and concepts such as energy, entropy, symmetry, response, multiscale interactions, and its potential relevance in terms of numerical modeling. We describe the Nambu reformulation of fluid dynamics, and the possible potential of such theory for constructing numerical models of the geophysical fluids. We focus on the very promising results on the statistical mechanics of quasi-equilibrium geophysical flows, which are extremely useful in the direction of constructing a robust theory of geophysical macro turbulence. The se...

  3. Climate Ambassador Programmes in Municipalities

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard; Pedersen, Stine Rahbek

    2016-01-01

    Some Danish municipalities have developed ambassador programmes which generate environmental and climate change mitigation efforts in local public administrations and institutions. This chapter analyses the characteristics and experiences of four ambassador programmes now operating...... in the municipalities of Furesø, Lyngby-Taarbæk, Frederiksberg and Hvidovre. Two of the ambassador programmes presented here focus primarily on climate change mitigation initiatives, and two have a broader focus on sustainable development. Important elements for the impact of these programmes are the networking among...

  4. Assessment of Human Health Vulnerability to Climate Variability and Change in Cuba

    OpenAIRE

    Bultó, Paulo Lázaro Ortíz; Rodríguez, Antonio Pérez; Valencia, Alina Rivero; Vega, Nicolás León; Gonzalez, Manuel Díaz; Carrera, Alina Pérez

    2006-01-01

    In this study we assessed the potential effects of climate variability and change on population health in Cuba. We describe the climate of Cuba as well as the patterns of climate-sensitive diseases of primary concern, particularly dengue fever. Analyses of the associations between climatic anomalies and disease patterns highlight current vulnerability to climate variability. We describe current adaptations, including the application of climate predictions to prevent disease outbreaks. Finally...

  5. Interactions of Mean Climate Change and Climate Variability on Food Security Extremes

    Science.gov (United States)

    Ruane, Alexander C.; McDermid, Sonali; Mavromatis, Theodoros; Hudson, Nicholas; Morales, Monica; Simmons, John; Prabodha, Agalawatte; Ahmad, Ashfaq; Ahmad, Shakeel; Ahuja, Laj R.

    2015-01-01

    Recognizing that climate change will affect agricultural systems both through mean changes and through shifts in climate variability and associated extreme events, we present preliminary analyses of climate impacts from a network of 1137 crop modeling sites contributed to the AgMIP Coordinated Climate-Crop Modeling Project (C3MP). At each site sensitivity tests were run according to a common protocol, which enables the fitting of crop model emulators across a range of carbon dioxide, temperature, and water (CTW) changes. C3MP can elucidate several aspects of these changes and quantify crop responses across a wide diversity of farming systems. Here we test the hypothesis that climate change and variability interact in three main ways. First, mean climate changes can affect yields across an entire time period. Second, extreme events (when they do occur) may be more sensitive to climate changes than a year with normal climate. Third, mean climate changes can alter the likelihood of climate extremes, leading to more frequent seasons with anomalies outside of the expected conditions for which management was designed. In this way, shifts in climate variability can result in an increase or reduction of mean yield, as extreme climate events tend to have lower yield than years with normal climate.C3MP maize simulations across 126 farms reveal a clear indication and quantification (as response functions) of mean climate impacts on mean yield and clearly show that mean climate changes will directly affect the variability of yield. Yield reductions from increased climate variability are not as clear as crop models tend to be less sensitive to dangers on the cool and wet extremes of climate variability, likely underestimating losses from water-logging, floods, and frosts.

  6. Theoretical numerical analysis

    CERN Document Server

    Wendroff, Burton

    2014-01-01

    Theoretical Numerical Analysis focuses on the presentation of numerical analysis as a legitimate branch of mathematics. The publication first elaborates on interpolation and quadrature and approximation. Discussions focus on the degree of approximation by polynomials, Chebyshev approximation, orthogonal polynomials and Gaussian quadrature, approximation by interpolation, nonanalytic interpolation and associated quadrature, and Hermite interpolation. The text then ponders on ordinary differential equations and solutions of equations. Topics include iterative methods for nonlinear systems, matri

  7. Exact Numerical Processing

    OpenAIRE

    García Chamizo, Juan Manuel; Mora Pascual, Jerónimo Manuel; Mora Mora, Higinio

    2003-01-01

    A model of an exact arithmetic processing is presented. We describe a representation format that gives us a greater expressive capability and covers a wider numerical set. The rational numbers are represented by means of fractional notation and explicit codification of its periodic part. We also give a brief description of exact arithmetic operations on the proposed format. This model constitutes a good alternative for the symbolic arithmetic, in special when numerical exact values are requir...

  8. Status of numerical relativity

    Indian Academy of Sciences (India)

    Masaru Shibata

    2004-10-01

    I describe the current status of numerical relativity from my personal point of view. Here, I focus mainly on explaining the numerical implementations necessary for simulating general relativistic phenomena such as the merger of compact binaries and stellar collapse, emphasizing the well-developed current status of such implementations that enable simulations for several astrophysical phenomena. Some of our latest results for simulation of binary neutron star mergers are briefly presented.

  9. Numerical computations with GPUs

    CERN Document Server

    Kindratenko, Volodymyr

    2014-01-01

    This book brings together research on numerical methods adapted for Graphics Processing Units (GPUs). It explains recent efforts to adapt classic numerical methods, including solution of linear equations and FFT, for massively parallel GPU architectures. This volume consolidates recent research and adaptations, covering widely used methods that are at the core of many scientific and engineering computations. Each chapter is written by authors working on a specific group of methods; these leading experts provide mathematical background, parallel algorithms and implementation details leading to

  10. Numerical transducer modelling

    DEFF Research Database (Denmark)

    Cutanda, Vicente

    1999-01-01

    Numerical modelling is of importance for the design, improvement and study of acoustic transducers such as microphones and accelerometers. Techniques like the boundary element method and the finite element method are the most common supplement to the traditional empirical and analytical approaches...... errors and instabilities in the computations of numerical solutions. An investigation to deal with this narrow-gap problem has been carried out....

  11. Evidence of climatic niche shift during biological invasion

    OpenAIRE

    Broennimann, Olivier; Urs A Treier; Müller-Schärer, Heinz; Thuiller, W.; Peterson, A. T.; Guisan, Antoine

    2007-01-01

    Niche-based models calibrated in the native range by relating species observations to climatic variables are commonly used to predict the potential spatial extent of species’ invasion. This climate matching approach relies on the assumption that invasive species conserve their climatic niche in the invaded ranges. We test this assumption by analysing the climatic niche spaces of Spotted Knapweed in western North America and Europe. We show with robust cross-continental data that a shift of th...

  12. Climate Change

    DEFF Research Database (Denmark)

    Richardson, Katherine; Steffen, Will; Liverman, Diana;

    Ministerial careers can be notoriously nasty, brutish, and short, with the doctrine of ministerial accountability leading to numerous prematurely ended political careers. But how do European democracies compare? Looking at evidence from seven countries, Jonathan Bright, Holger Doring, and Conor L...

  13. The Impact of Climate on Holiday Destination Choice

    Energy Technology Data Exchange (ETDEWEB)

    Bigano, A. [Fondazione Eni Enrico Mattei, Milan (Italy); Hamilton, J.M. [Research unit Sustainability and Global Change, Hamburg University and Centre for Marine and Atmospheric Science, Hamburg (Germany); Tol, R.S.J. [Institute for Environmental Studies, Vrije Universiteit, Amsterdam (Netherlands)

    2006-06-15

    The holiday destination choice is analysed for tourists from 45 countries, representing all continents and all climates. Tourists are deterred by distance, political instability and poverty, and attracted to coasts. Tourists prefer countries with a sunny yet mild climate, shun climates that are too hot or too cold. A country's tourists' aversion for poverty and distance can be predicted by that country's average per capita income. The preferred holiday climate is the same for all tourists, independent of the home climate. However, tourists from hotter climates have more pronounced preferences.

  14. SSCM analyses of biomass resources in Randers, Norddjurs and Syddjurs

    Energy Technology Data Exchange (ETDEWEB)

    2010-07-15

    This project has been commissioned by ENERCOAST whose overall aim is to stimulate increased use and production of biomass, and create a market for bio energy in the North Sea region. The Enercoast project has been financed by the EU Interreg IVB with partners from Denmark, Germany, United Kingdom, Sweden and Norway. The Danish project leader is AgroBusiness Park/ CBMI /Innovation Centre for Bioenergy and Environmental Technology. Central Region Denmark is co-financing 34% of the Danish portion of the project, while the municipalities of Norddjurs, Syddjurs and Randers are contributing to the project with their working hours. The Danish portion of this project focuses on three Danish municipalities, Randers, Norddjurs, and Syddjurs, and the possibilities to reach local energy and climate targets by increasing the use and production of biomass. The project is divided into 6 phases of which this report is part of the second and third phase which focus on analyses of various biomass resources on a local level including carrying out SSCM analyses of these resources. The aim of this report is to assess the sustainability of relevant bio energy supply chains related to the resource accessibility in the three municipalities with main focus on biogas, straw, wood residues and energy crops for combined heat and power production. Sustainable Supply Chain Management (SSCM) is a concept that has many definitions and the methodologies used to approach this are numerous. In this report the SSCM analysis is used to answer the following question: What are the possibilities of increased use of biomass for energy production in the three municipalities, and what consequences are associated with the utilisation of each of the selected resources described through our case studies? For each of the resource case studies an overview of the supply chain is illustrated through a matrix. Each step of the supply chain from the primal material production in on end to heat and electricity

  15. Population effects of increased climate variation

    OpenAIRE

    Drake, John M.

    2005-01-01

    Global circulation models predict and numerous observations confirm that anthropogenic climate change has altered high-frequency climate variability. However, it is not yet well understood how changing patterns of environmental variation will affect wildlife population dynamics and other ecological processes. Theory predicts that a population's long-run growth rate is diminished and the chance of population extinction is increased as environmental variation increases. This results from the fa...

  16. The Evaluation of Climate Change Risks

    OpenAIRE

    Popescu, Constantin; Maria-Luiza HRESTIC

    2012-01-01

    Nowadays, it is acknowledged that climatic changes represent a serious threat for the environment and, so, this problem has been approached at numerous conferences, conventions and summits. The climate is strongly influenced by the changes in the atmospheric concentrations of certain gases that hold the solar radiations on the Earth’s surface (the greenhouse effect). The water vapors and the carbon dioxide (CO2) present in the atmosphere have always generated a natural greenhouse effect, with...

  17. Global post-Kyoto scenario analyses at PSI

    Energy Technology Data Exchange (ETDEWEB)

    Kypreos, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Scenario analyses are described here using the Global MARKAL-Macro Trade (GMMT) model to study the economic implications of the Kyoto Protocol to the UN Convention on Climate change. Some conclusions are derived in terms of efficient implementations of the post-Kyoto extensions of the Protocol. (author) 2 figs., 5 refs.

  18. Frontiers in Numerical Relativity

    Science.gov (United States)

    Evans, Charles R.; Finn, Lee S.; Hobill, David W.

    2011-06-01

    Preface; Participants; Introduction; 1. Supercomputing and numerical relativity: a look at the past, present and future David W. Hobill and Larry L. Smarr; 2. Computational relativity in two and three dimensions Stuart L. Shapiro and Saul A. Teukolsky; 3. Slowly moving maximally charged black holes Robert C. Ferrell and Douglas M. Eardley; 4. Kepler's third law in general relativity Steven Detweiler; 5. Black hole spacetimes: testing numerical relativity David H. Bernstein, David W. Hobill and Larry L. Smarr; 6. Three dimensional initial data of numerical relativity Ken-ichi Oohara and Takashi Nakamura; 7. Initial data for collisions of black holes and other gravitational miscellany James W. York, Jr.; 8. Analytic-numerical matching for gravitational waveform extraction Andrew M. Abrahams; 9. Supernovae, gravitational radiation and the quadrupole formula L. S. Finn; 10. Gravitational radiation from perturbations of stellar core collapse models Edward Seidel and Thomas Moore; 11. General relativistic implicit radiation hydrodynamics in polar sliced space-time Paul J. Schinder; 12. General relativistic radiation hydrodynamics in spherically symmetric spacetimes A. Mezzacappa and R. A. Matzner; 13. Constraint preserving transport for magnetohydrodynamics John F. Hawley and Charles R. Evans; 14. Enforcing the momentum constraints during axisymmetric spacelike simulations Charles R. Evans; 15. Experiences with an adaptive mesh refinement algorithm in numerical relativity Matthew W. Choptuik; 16. The multigrid technique Gregory B. Cook; 17. Finite element methods in numerical relativity P. J. Mann; 18. Pseudo-spectral methods applied to gravitational collapse Silvano Bonazzola and Jean-Alain Marck; 19. Methods in 3D numerical relativity Takashi Nakamura and Ken-ichi Oohara; 20. Nonaxisymmetric rotating gravitational collapse and gravitational radiation Richard F. Stark; 21. Nonaxisymmetric neutron star collisions: initial results using smooth particle hydrodynamics

  19. Global Air Quality and Climate

    Science.gov (United States)

    Fiore, Arlene M.; Naik, Vaishali; Steiner, Allison; Unger, Nadine; Bergmann, Dan; Prather, Michael; Righi, Mattia; Rumbold, Steven T.; Shindell, Drew T.; Skeie, Ragnhild B.; Sudo, Kengo; Szopa, Sophie; Horowitz, Larry W.; Takemura, Toshihiko; Zeng, Guang; Cameron-Smith, Philip J.; Cionni, Irene; Collins, William J.; Dalsoren, Stig; Eyring, Veronika; Folberth, Gerd A.; Ginoux, Paul; Josse, Batrice; Lamarque, Jean-Francois; OConnor, Fiona M.; Mackenzie, Ian A.; Nagashima, Tatsuya; Shindell, Drew Todd; Spracklen, Dominick V.

    2012-01-01

    Emissions of air pollutants and their precursors determine regional air quality and can alter climate. Climate change can perturb the long-range transport, chemical processing, and local meteorology that influence air pollution. We review the implications of projected changes in methane (CH4), ozone precursors (O3), and aerosols for climate (expressed in terms of the radiative forcing metric or changes in global surface temperature) and hemispheric-to-continental scale air quality. Reducing the O3 precursor CH4 would slow near-term warming by decreasing both CH4 and tropospheric O3. Uncertainty remains as to the net climate forcing from anthropogenic nitrogen oxide (NOx) emissions, which increase tropospheric O3 (warming) but also increase aerosols and decrease CH4 (both cooling). Anthropogenic emissions of carbon monoxide (CO) and non-CH4 volatile organic compounds (NMVOC) warm by increasing both O3 and CH4. Radiative impacts from secondary organic aerosols (SOA) are poorly understood. Black carbon emission controls, by reducing the absorption of sunlight in the atmosphere and on snow and ice, have the potential to slow near-term warming, but uncertainties in coincident emissions of reflective (cooling) aerosols and poorly constrained cloud indirect effects confound robust estimates of net climate impacts. Reducing sulfate and nitrate aerosols would improve air quality and lessen interference with the hydrologic cycle, but lead to warming. A holistic and balanced view is thus needed to assess how air pollution controls influence climate; a first step towards this goal involves estimating net climate impacts from individual emission sectors. Modeling and observational analyses suggest a warming climate degrades air quality (increasing surface O3 and particulate matter) in many populated regions, including during pollution episodes. Prior Intergovernmental Panel on Climate Change (IPCC) scenarios (SRES) allowed unconstrained growth, whereas the Representative

  20. The U.S. National Climate Assessment: The Science of Climate Change

    Science.gov (United States)

    Walsh, J. E.; Wuebbles, D. J.; Hayhoe, K.; Kunkel, K.; Stephens, G. L.; Thorne, P.; Wehner, M. F.; Willis, J. K.; Vose, R.

    2012-12-01

    The U.S. National Climate Assessment (NCA) draws upon the latest scientific understanding of climate and climate change, synthesizing recent advances in the understanding of the science of climate change, and providing a succinct overview of the past and projected effects of climate change on the United States. This presentation will provide an overview of draft findings from the 2013 NCA report chapter on the science of climate change, including observed trends and projected future climate changes for the United States. The chapter and the associated appendix discusses both natural- and human-induced forcings on the climate system, the resulting effects on temperature and precipitation, including the effects of natural variability, and examines shifts in the growing season, frequency and intensity of extreme weather events, sea level rise, ice cover, and ocean acidification. The chapter includes regional analyses, including evaluations for Alaska and Hawaii, and well as for various regions of the continental United States. We also developed a special appendix for the assessment on commonly asked questions about the science of climate change. The chapter provides a foundation for the entire NCA report, which evaluates climate change trends and impacts in each region of the United States and on various socioeconomic and ecological sectors. It is also a key contribution to international climate assessments, including the Intergovernmental Panel on Climate Change, especially with respect to the state of knowledge of ongoing and projected changes of extreme events (heat waves, droughts, hurricanes, heavy precipitation) in the United States.

  1. Climate - Options for broadening climate policy

    OpenAIRE

    Aerts JCJH; Asselt H van; Bakker SJA; Bayangos V; Beers C van; Berk MM; Biermann F; Bouwer LM; van Bree L; Dorland K; Elzen ME den; Gupta J; Heemst J van; Jansen JC; Nabuurs GJ

    2005-01-01

    In this study ways are explored to increase the policy coherence between the climate regime and a selected number of climate relevant policy areas, by adding a non-climate policy track to national and international climate strategies. The report assesses first the potential, synergies and trade-offs of linking the climate regime to relevant other policy areas, including poverty reduction, land-use, security of energy supply, trade and finance and air quality and health. Next the possibilities...

  2. National climate strategy. Finland. Government report to Parliament

    International Nuclear Information System (INIS)

    At the session held in Kyoto in 1997, the Parties to the Climate Convention agreed on legally binding targets for reducing greenhouse gas emissions. Under the so- called Kyoto Protocol, the Member States of the European Community and the European Union shall reduce their annual emissions by eight per cent annually during the years 2008-2012 compared to the 1990 level. Within the Community, the targets have been allotted among the Member States so that Finland's annual greenhouse gas emissions may amount on average to no more than the 1990 level during the commitment period 2008-2012. This National Climate Strategy, submitted to Parliament in the form of a Government report, contains the principles, targets and measures that the Government finds necessary in order to meet our national target. The background material for the strategy consists of sector-specific reports made by the various ministries. The ministerial working group has coordinated the preparation of the strategy. For the strategy, the ministries have carried out and commissioned numerous separate analyses and studies, the reports of which have been published in the course of preparing the strategy. Based on these end the sector-specific reports, a background report to the National Climate Programme entitled 'The Need for and Possibilities of Reducing Greenhouse Gas Emissions in Finland' was compiled for the ministerial working group. The report was co-ordinated by the Kyoto contact network composed of civil servants from the various ministries. The report describes in more detail the factors influencing economic growth, energy consumption and production, and other elements affecting the development of greenhouse gases, which were used as underlying assumptions when determining the recommendations for action under the strategy. The economic and other effects of alternative courses of action were also analysed and described in the above-mentioned background study. It has been published in the Internet on

  3. Climate Concerns

    Institute of Scientific and Technical Information of China (English)

    TANG YUANKAI

    2010-01-01

    @@ From June to August 2009, the western part of northeast China's Liaoning Province suffered from drought and extremely high temperatures, which damaged about 4.9 million hectares of farmland. Almost 827,000 hectares yielded no harvest as a result of the drought and 3 million people were impacted. The villagers might not know that a conference held in December on the other side of the globe has something to do with their hard times, but many are waking up to the reality that the disastrous effects of climate change have already begun to exert great influence on people's lives.

  4. Climate Change

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    According to the National Academy of Sciences in American,the Earth's surface temperature has risen by about 1 degree Fahrenheit in the past century, with accelerated warming during the past two decades. There is new and stronger evidence that most of the warming over the last 50 years is attributable to human activities.Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases-primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed although uncertainties exist about exactly how earth's climate responds to them.

  5. Classifying climate change adaptation frameworks

    Science.gov (United States)

    Armstrong, Jennifer

    2014-05-01

    Complex socio-ecological demographics are factors that must be considered when addressing adaptation to the potential effects of climate change. As such, a suite of deployable climate change adaptation frameworks is necessary. Multiple frameworks that are required to communicate the risks of climate change and facilitate adaptation. Three principal adaptation frameworks have emerged from the literature; Scenario - Led (SL), Vulnerability - Led (VL) and Decision - Centric (DC). This study aims to identify to what extent these adaptation frameworks; either, planned or deployed are used in a neighbourhood vulnerable to climate change. This work presents a criterion that may be used as a tool for identifying the hallmarks of adaptation frameworks and thus enabling categorisation of projects. The study focussed on the coastal zone surrounding the Sizewell nuclear power plant in Suffolk in the UK. An online survey was conducted identifying climate change adaptation projects operating in the study area. This inventory was analysed to identify the hallmarks of each adaptation project; Levels of dependency on climate model information, Metrics/units of analysis utilised, Level of demographic knowledge, Level of stakeholder engagement, Adaptation implementation strategies and Scale of adaptation implementation. The study found that climate change adaptation projects could be categorised, based on the hallmarks identified, in accordance with the published literature. As such, the criterion may be used to establish the matrix of adaptation frameworks present in a given area. A comprehensive summary of the nature of adaptation frameworks in operation in a locality provides a platform for further comparative analysis. Such analysis, enabled by the criterion, may aid the selection of appropriate frameworks enhancing the efficacy of climate change adaptation.

  6. The butterfly and the tornado: chaos theory and climate change

    International Nuclear Information System (INIS)

    In this book, the author addresses two topics: the theory of chaos, and climate change. The first chapters propose a prehistory and history of chaos, from Newton, Laplace and Lorenz and their controversies as far as prehistory of chaos is concerned, and with different works performed during the twentieth century (Hadamard, Birkhoff, van der Pol, and so on, until Lorenz, the MIT meteorologist and the discovery of the Butterfly Effect, and more recent works by Yorke and Feigenbaum about the logistic equation and the transition to chaos) as far as recent history is concerned. The next chapter describes the deterministic chaos by introducing non linear dynamic systems and distinguishing three regimes: steady, periodic or chaotic. The second part addresses climate change, outlines that global warming is a reality, that the main origin is the increase of greenhouse effect, and that CO2 emissions related to human activity are the main origin of this additional greenhouse effect. The author notably recalls the controversy about the analysis of the global average temperature curve, discusses the assessment of average temperatures from a statistical point of view and in relationship with the uneven distribution of survey stations. The last chapter discusses the numerical modelling of time and climate, and the validity of the Butterfly Effect. The author also proposes a brief overview of the IPCC, discusses the emergence of an international climate policy (UN convention, Kyoto protocol), evokes the use of game theory to ensure a convergence of treaties, and analyses the economic situation of several countries (including Spain) since the Kyoto protocol

  7. Numerical Propulsion System Simulation Architecture

    Science.gov (United States)

    Naiman, Cynthia G.

    2004-01-01

    The Numerical Propulsion System Simulation (NPSS) is a framework for performing analysis of complex systems. Because the NPSS was developed using the object-oriented paradigm, the resulting architecture is an extensible and flexible framework that is currently being used by a diverse set of participants in government, academia, and the aerospace industry. NPSS is being used by over 15 different institutions to support rockets, hypersonics, power and propulsion, fuel cells, ground based power, and aerospace. Full system-level simulations as well as subsystems may be modeled using NPSS. The NPSS architecture enables the coupling of analyses at various levels of detail, which is called numerical zooming. The middleware used to enable zooming and distributed simulations is the Common Object Request Broker Architecture (CORBA). The NPSS Developer's Kit offers tools for the developer to generate CORBA-based components and wrap codes. The Developer's Kit enables distributed multi-fidelity and multi-discipline simulations, preserves proprietary and legacy codes, and facilitates addition of customized codes. The platforms supported are PC, Linux, HP, Sun, and SGI.

  8. Numerical modeling of foam flows

    International Nuclear Information System (INIS)

    Liquid foam flows are involved in numerous applications, e.g. food and cosmetics industries, oil extraction, nuclear decontamination. Moreover, their study leads to fundamental knowledge: as it is easier to manipulate and analyse, foam is used as a model material to understand the flow of emulsions, polymers, pastes, or cell aggregates, all of which display both solid and liquid behaviour. Systematic experiments performed by Francois Graner et al. provide precise data that emphasize the non Newtonian properties of the foam. Meanwhile, Pierre Saramito proposed a visco-elasto-plastic continuous tensorial model, akin to predict the behaviour of the foam. The goal of this thesis is to understand this complex behaviour, using these two elements. We have built and validated a resolution algorithm based on a bidimensional finite elements methods. The numerical solutions are in excellent agreement with the spatial distribution of all measured quantities, and confirm the predictive capabilities of the model. The dominant parameters have been identified and we evidenced the fact that the viscous, elastic, and plastic contributions to the flow have to be treated simultaneously in a tensorial formalism. We provide a substantial contribution to the understanding of foams and open the path to realistic simulations of complex VEP flows for industrial applications. (author)

  9. Choice of baseline climate data impacts projected species' responses to climate change.

    Science.gov (United States)

    Baker, David J; Hartley, Andrew J; Butchart, Stuart H M; Willis, Stephen G

    2016-07-01

    Climate data created from historic climate observations are integral to most assessments of potential climate change impacts, and frequently comprise the baseline period used to infer species-climate relationships. They are often also central to downscaling coarse resolution climate simulations from General Circulation Models (GCMs) to project future climate scenarios at ecologically relevant spatial scales. Uncertainty in these baseline data can be large, particularly where weather observations are sparse and climate dynamics are complex (e.g. over mountainous or coastal regions). Yet, importantly, this uncertainty is almost universally overlooked when assessing potential responses of species to climate change. Here, we assessed the importance of historic baseline climate uncertainty for projections of species' responses to future climate change. We built species distribution models (SDMs) for 895 African bird species of conservation concern, using six different climate baselines. We projected these models to two future periods (2040-2069, 2070-2099), using downscaled climate projections, and calculated species turnover and changes in species-specific climate suitability. We found that the choice of baseline climate data constituted an important source of uncertainty in projections of both species turnover and species-specific climate suitability, often comparable with, or more important than, uncertainty arising from the choice of GCM. Importantly, the relative contribution of these factors to projection uncertainty varied spatially. Moreover, when projecting SDMs to sites of biodiversity importance (Important Bird and Biodiversity Areas), these uncertainties altered site-level impacts, which could affect conservation prioritization. Our results highlight that projections of species' responses to climate change are sensitive to uncertainty in the baseline climatology. We recommend that this should be considered routinely in such analyses. PMID:26950769

  10. Choice of baseline climate data impacts projected species' responses to climate change.

    Science.gov (United States)

    Baker, David J; Hartley, Andrew J; Butchart, Stuart H M; Willis, Stephen G

    2016-07-01

    Climate data created from historic climate observations are integral to most assessments of potential climate change impacts, and frequently comprise the baseline period used to infer species-climate relationships. They are often also central to downscaling coarse resolution climate simulations from General Circulation Models (GCMs) to project future climate scenarios at ecologically relevant spatial scales. Uncertainty in these baseline data can be large, particularly where weather observations are sparse and climate dynamics are complex (e.g. over mountainous or coastal regions). Yet, importantly, this uncertainty is almost universally overlooked when assessing potential responses of species to climate change. Here, we assessed the importance of historic baseline climate uncertainty for projections of species' responses to future climate change. We built species distribution models (SDMs) for 895 African bird species of conservation concern, using six different climate baselines. We projected these models to two future periods (2040-2069, 2070-2099), using downscaled climate projections, and calculated species turnover and changes in species-specific climate suitability. We found that the choice of baseline climate data constituted an important source of uncertainty in projections of both species turnover and species-specific climate suitability, often comparable with, or more important than, uncertainty arising from the choice of GCM. Importantly, the relative contribution of these factors to projection uncertainty varied spatially. Moreover, when projecting SDMs to sites of biodiversity importance (Important Bird and Biodiversity Areas), these uncertainties altered site-level impacts, which could affect conservation prioritization. Our results highlight that projections of species' responses to climate change are sensitive to uncertainty in the baseline climatology. We recommend that this should be considered routinely in such analyses.

  11. Climate Analytics as a Service

    Science.gov (United States)

    Schnase, John L.; Duffy, Daniel Q.; McInerney, Mark A.; Webster, W. Phillip; Lee, Tsengdar J.

    2014-01-01

    Climate science is a big data domain that is experiencing unprecedented growth. In our efforts to address the big data challenges of climate science, we are moving toward a notion of Climate Analytics-as-a-Service (CAaaS). CAaaS combines high-performance computing and data-proximal analytics with scalable data management, cloud computing virtualization, the notion of adaptive analytics, and a domain-harmonized API to improve the accessibility and usability of large collections of climate data. MERRA Analytic Services (MERRA/AS) provides an example of CAaaS. MERRA/AS enables MapReduce analytics over NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) data collection. The MERRA reanalysis integrates observational data with numerical models to produce a global temporally and spatially consistent synthesis of key climate variables. The effectiveness of MERRA/AS has been demonstrated in several applications. In our experience, CAaaS is providing the agility required to meet our customers' increasing and changing data management and data analysis needs.

  12. Numerical Algorithms Based on Biorthogonal Wavelets

    Science.gov (United States)

    Ponenti, Pj.; Liandrat, J.

    1996-01-01

    Wavelet bases are used to generate spaces of approximation for the resolution of bidimensional elliptic and parabolic problems. Under some specific hypotheses relating the properties of the wavelets to the order of the involved operators, it is shown that an approximate solution can be built. This approximation is then stable and converges towards the exact solution. It is designed such that fast algorithms involving biorthogonal multi resolution analyses can be used to resolve the corresponding numerical problems. Detailed algorithms are provided as well as the results of numerical tests on partial differential equations defined on the bidimensional torus.

  13. Intertemporal social choice and climate stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Howarth, R.B. [Dartmouth College, Hanover, NH (United States). Environmental Studies Program

    2001-07-01

    This paper examines the implications of alternative approaches to intertemporal social choice in a numerically calibrated model of interactions between global climate change and the world economy. Under cost-benefit analysis, relatively modest steps towards greenhouse gas emissions abatement are justified as economically efficient. Under classical utilitarianism and the precautionary principle, in contrast, aggressive steps towards climate stabilization emerge as socially optimal. The paper reviews the value judgement that support each of these normative approaches, arguing that the precautionary principle is most loosely tied to the goals and objectives of the Framework Convention on Climate Change. (Author)

  14. Data Sources for the Analyses

    Data.gov (United States)

    U.S. Environmental Protection Agency — Links are provided for the National Wetlands Inventory, National Hydrography Dataset, and the WorldClim-Global Climate Data source data websites This dataset is...

  15. Solar magnetic fields and terrestrial climate

    CERN Document Server

    Georgieva, Katya; Kirov, Boian

    2014-01-01

    Solar irradiance is considered one of the main natural factors affecting terrestrial climate, and its variations are included in most numerical models estimating the effects of natural versus anthropogenic factors for climate change. Solar wind causing geomagnetic disturbances is another solar activity agent whose role in climate change is not yet fully estimated but is a subject of intense research. For the purposes of climate modeling, it is essential to evaluate both the past and the future variations of solar irradiance and geomagnetic activity which are ultimately due to the variations of solar magnetic fields. Direct measurements of solar magnetic fields are available for a limited period, but can be reconstructed from geomagnetic activity records. Here we present a reconstruction of total solar irradiance based on geomagnetic data, and a forecast of the future irradiance and geomagnetic activity relevant for the expected climate change.

  16. Probability Measures for Numerical Solutions of Differential Equations

    OpenAIRE

    Conrad, Patrick R.; Girolami, Mark; Särkkä, Simo; Stuart, Andrew; Zygalakis, Konstantinos

    2015-01-01

    In this paper, we present a formal quantification of epistemic uncertainty induced by numerical solutions of ordinary and partial differential equation models. Numerical solutions of differential equations contain inherent uncertainties due to the finite dimensional approximation of an unknown and implicitly defined function. When statistically analysing models based on differential equations describing physical, or other naturally occurring, phenomena, it is therefore important to explicitly...

  17. Processes Understanding of Decadal Climate Variability

    Science.gov (United States)

    Prömmel, Kerstin; Cubasch, Ulrich

    2016-04-01

    The realistic representation of decadal climate variability in the models is essential for the quality of decadal climate predictions. Therefore, the understanding of those processes leading to decadal climate variability needs to be improved. Several of these processes are already included in climate models but their importance has not yet completely been clarified. The simulation of other processes requires sometimes a higher resolution of the model or an extension by additional subsystems. This is addressed within one module of the German research program "MiKlip II - Decadal Climate Predictions" (http://www.fona-miklip.de/en/) with a focus on the following processes. Stratospheric processes and their impact on the troposphere are analysed regarding the climate response to aerosol perturbations caused by volcanic eruptions and the stratospheric decadal variability due to solar forcing, climate change and ozone recovery. To account for the interaction between changing ozone concentrations and climate a computationally efficient ozone chemistry module is developed and implemented in the MiKlip prediction system. The ocean variability and air-sea interaction are analysed with a special focus on the reduction of the North Atlantic cold bias. In addition, the predictability of the oceanic carbon uptake with a special emphasis on the underlying mechanism is investigated. This addresses a combination of physical, biological and chemical processes.

  18. Climate and environmental change in China. 1951-2012

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dahe [Chinese Academy of Sciences, Lanzhou (China). Cold and Arid Regions Environmental and Engineering Research Institute; Academy of Meteorological Sciences, Beijing, BJ (China). State Meteorological Administration; Ding, Yongjian [Chinese Academy of Sciences, Lanzhou (China). Cold and Arid Regions Environmental and Engineering Research Institute; Mu, Mu (ed.) [Chinese Academy of Sciences, Qingdao (China). Inst. of Oceanology

    2016-02-01

    Through numerous color figures and tables, this book presents the most up-to-date knowledge on climate and environmental change in China. It documents the evidence and attribution of climate and environmental changes in the past few decades and discusses the impacts of climate change on environments, economy, and society. The book further provides projections of climate change and its impacts in the future. Finally, it offers the climate change mitigation and adaption technologies with strategic options which will be of interest for policy makers, researchers and the general public as well.

  19. Climate and environmental change in China. 1951-2012

    International Nuclear Information System (INIS)

    Through numerous color figures and tables, this book presents the most up-to-date knowledge on climate and environmental change in China. It documents the evidence and attribution of climate and environmental changes in the past few decades and discusses the impacts of climate change on environments, economy, and society. The book further provides projections of climate change and its impacts in the future. Finally, it offers the climate change mitigation and adaption technologies with strategic options which will be of interest for policy makers, researchers and the general public as well.

  20. Uncertainty of the Numerical Solution of a Nonlinear System's Long-term Behavior and Global Convergence of the Numerical Pattern

    Institute of Scientific and Technical Information of China (English)

    胡淑娟; 丑纪范

    2004-01-01

    The computational uncertainty principle in nonlinear ordinary differential equations makes the numerical solution of the long-term behavior of nonlinear atmospheric equations have no meaning. The main reason is that, in the error analysis theory of present-day computational mathematics, the non-linear process between truncation error and rounding erroris treated as a linear operation. In this paper, based on the operator equations of large-scale atmospheric movement, the above limitation is overcome by using the notion of cell mapping. Through studying the global asymptotic characteristics of the numerical pattern of the large-scale atmospheric equations, the definitions of the global convergence and an appropriate discrete algorithm of the numerical pattern are put forward. Three determinant theorems about the global convergence of the numerical pattern are presented, which provide the theoretical basis for constructing the globally convergent numerical pattern. Further, it is pointed out that only a globally convergent numerical pattern can improve the veracity of climatic prediction.

  1. Introduction to Numerical Methods

    Energy Technology Data Exchange (ETDEWEB)

    Schoonover, Joseph A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-14

    These are slides for a lecture for the Parallel Computing Summer Research Internship at the National Security Education Center. This gives an introduction to numerical methods. Repetitive algorithms are used to obtain approximate solutions to mathematical problems, using sorting, searching, root finding, optimization, interpolation, extrapolation, least squares regresion, Eigenvalue problems, ordinary differential equations, and partial differential equations. Many equations are shown. Discretizations allow us to approximate solutions to mathematical models of physical systems using a repetitive algorithm and introduce errors that can lead to numerical instabilities if we are not careful.

  2. Matlab numerical calculations

    CERN Document Server

    Lopez, Cesar

    2015-01-01

    MATLAB is a high-level language and environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spreadsheets or traditional programming languages, such as C/C++ or Java. This book is designed for use as a scientific/business calculator so that you can get numerical solutions to problems involving a wide array of mathematics using MATLAB. Just look up the function y

  3. Numerical Modeling of Ocean Circulation

    Science.gov (United States)

    Miller, Robert N.

    2007-01-01

    The modelling of ocean circulation is important not only for its own sake, but also in terms of the prediction of weather patterns and the effects of climate change. This book introduces the basic computational techniques necessary for all models of the ocean and atmosphere, and the conditions they must satisfy. It describes the workings of ocean models, the problems that must be solved in their construction, and how to evaluate computational results. Major emphasis is placed on examining ocean models critically, and determining what they do well and what they do poorly. Numerical analysis is introduced as needed, and exercises are included to illustrate major points. Developed from notes for a course taught in physical oceanography at the College of Oceanic and Atmospheric Sciences at Oregon State University, this book is ideal for graduate students of oceanography, geophysics, climatology and atmospheric science, and researchers in oceanography and atmospheric science. Features examples and critical examination of ocean modelling and results Demonstrates the strengths and weaknesses of different approaches Includes exercises to illustrate major points and supplement mathematical and physical details

  4. Targeting climate diversity in conservation planning to build resilience to climate change

    Science.gov (United States)

    Heller, Nicole E.; Kreitler, Jason R.; Ackerly, David; Weiss, Stuart; Recinos, Amanda; Branciforte, Ryan; Flint, Lorraine E.; Flint, Alan L.; Micheli, Elisabeth

    2015-01-01

    consistently show greater climate stability than homogenous areas. The analysis suggests that utilizing high-resolution climate and hydrological data in conservation planning improves the likely resilience of biodiversity to climate change. We used these analyses to suggest new conservation priorities for the San Francisco Bay Area.

  5. A numerical model of coastline deformation for sandy beach at downstream of a jetty

    Institute of Scientific and Technical Information of China (English)

    SUN Linyun; PAN Junning; XING Fu; LIU Jiaju

    2004-01-01

    A reformed numerical model based on the "one-line theory" for beach deformation is presented. In this model, thechange of beach slope during coastline procession is eonsidered. A wave numerical model combined with wave re-fraction, diffraction and reflection is used to simulate wave climate to increase numerical accuracy. The results showthat the numerical model has a good precision based on the adequate field data. The results can be applied to practical engineering.

  6. Analysis of numerical methods

    CERN Document Server

    Isaacson, Eugene

    1994-01-01

    This excellent text for advanced undergraduates and graduate students covers norms, numerical solution of linear systems and matrix factoring, iterative solutions of nonlinear equations, eigenvalues and eigenvectors, polynomial approximation, and other topics. It offers a careful analysis and stresses techniques for developing new methods, plus many examples and problems. 1966 edition.

  7. Numerical analysis using Sage

    CERN Document Server

    Anastassiou, George A

    2015-01-01

    This is the first numerical analysis text to use Sage for the implementation of algorithms and can be used in a one-semester course for undergraduates in mathematics, math education, computer science/information technology, engineering, and physical sciences. The primary aim of this text is to simplify understanding of the theories and ideas from a numerical analysis/numerical methods course via a modern programming language like Sage. Aside from the presentation of fundamental theoretical notions of numerical analysis throughout the text, each chapter concludes with several exercises that are oriented to real-world application.  Answers may be verified using Sage.  The presented code, written in core components of Sage, are backward compatible, i.e., easily applicable to other software systems such as Mathematica®.  Sage is  open source software and uses Python-like syntax. Previous Python programming experience is not a requirement for the reader, though familiarity with any programming language is a p...

  8. Global analysis theory of climate system and its applications

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The idea and main theoretical results of the global analysis theory of climate system are briefly summarized in this paper. A theorem on the global behavior of climate system is given, i.e. there exists a global attractor in the dynamical equations of climate, any state of climate system will be evolved into the global attractor as time increases, indicating the nonlinear adjustment process of climate system to external forcing. The different effects of external forcing, dissipation and nonlinearity on the long-term behavior of solutions are pointed out, and some main applications of the global analysis theory are also introduced. Especially, three applications, the adjustment and evolution processes of climate, the principle of numerical model design and the optimally numerical integration, are discussed.

  9. Effects of climate change on water demand and water availability for power plants - examples for the German capital Berlin

    Science.gov (United States)

    Voegele, Stefan; Koch, Hagen; Grünewald, Uwe

    2010-05-01

    Effects of climate change on water demand and water availability for power plants - examples for the German capital Berlin Stefan Vögelea, Hagen Kochb&c, Uwe Grünewaldb a Forschungszentrum Jülich, Institute of Energy Research - Systems Analysis and Technology Evaluation, D-52425 Jülich, Germany b Brandenburg University of Technology Cottbus, Chair Hydrology and Water Resources Management, P.O. Box. 101 344, D-03013 Cottbus, Germany c Potsdam Institute for Climate Impact Research, Research Domain Climate Impacts and Vulnerabilities, P.O. Box 601203, D-14412 Potsdam, Germany Numerous power plants in Europe had to be throttled in the summer months of the years 2003 and 2006 due to water shortages and high water temperatures. Therefore, the effects of climate change on water availability and water temperature, and their effects on electric power generation in power plants have received much attention in the last years. The water demand of a power plant for cooling depends on the temperature of the surface waters from which the cooling water is withdrawn. Furthermore, air temperature and air humidity influence the water demand if a cooling tower is used. Beside climatic parameters, the demand for water depends on economic and technological factors as well as on the electricity demand and the socio-political framework. Since the different systems are connected with certain levels of uncertainty, scenarios of socio-economic development and climate change should be used in analyses of climate change on power plants and to identify adaptation measures. In this presentation the effects of global change, comprising technological, socio-economic and climate change, and adaptation options to water shortages for power plants in the German capital Berlin in the short- and long-term are analysed. The interconnection between power plants, i.e. water demand, and water resources management, i.e. water availability, is described in detail. By changing the cooling system of power

  10. Numerical simulation and analysis of axial instabilities occurrence and development in turbomachines. Application to a break transient in a helium nuclear reactor; Simulation numerique et analyse du declenchement et du developpement des instabilites axiales dans les turbomachines: application a un transitoire de breche dans un reacteur nucleaire a helium

    Energy Technology Data Exchange (ETDEWEB)

    Tauveron, N

    2006-02-15

    The subject of the present work was to develop models able to simulate axial instabilities occurrence and development in multistage turbomachines. The construction of a 1D unsteady axisymmetric model of internal flow in a turbomachine (at the scale of the row) has followed different steps: generation of steady correlations, adapted to different regimes (off-design conditions, low mass flowrate, negative mass flow rate); building of a model able to describe transient behaviour; use of implicit time schemes adapted to long transients; validation of the model in comparison of experimental investigations, measurements and numerical results from the bibliography. This model is integrated in a numerical tool, which has the capacity to describe the gas dynamics in a complete circuit containing different elements (ducts, valves, plenums). Thus, the complete model can represent the coupling between local and global phenomena, which is a very important mechanism in axial instability occurrence and development. An elementary theory has also been developed, based on a generalisation of Greitzer's model. These models, which were validated on various configurations, have provided complementary elements for the validation of the complete model. They have also allowed a more comprehensive description of physical phenomena at stake in instability occurrence and development by quantifying various effects (inertia, compressibility, performance levels) and underlying the main phenomena (in particular the collapse and recovery kinetics of the plenum), which were the only retained in the final elementary theory. The models were first applied to academic configurations (compression system), and then to an innovative industrial project: a helium cooled fast nuclear reactor with a Brayton cycle. The use of the models have brought comprehensive elements to surge occurrence due to a break event. It has been shown that surge occurrence is highly dependent of break location and that surge

  11. The meaning and measurement of implementation climate

    Directory of Open Access Journals (Sweden)

    Bergmire Dawn M

    2011-07-01

    Full Text Available Abstract Background Climate has a long history in organizational studies, but few theoretical models integrate the complex effects of climate during innovation implementation. In 1996, a theoretical model was proposed that organizations could develop a positive climate for implementation by making use of various policies and practices that promote organizational members' means, motives, and opportunities for innovation use. The model proposes that implementation climate--or the extent to which organizational members perceive that innovation use is expected, supported, and rewarded--is positively associated with implementation effectiveness. The implementation climate construct holds significant promise for advancing scientific knowledge about the organizational determinants of innovation implementation. However, the construct has not received sufficient scholarly attention, despite numerous citations in the scientific literature. In this article, we clarify the meaning of implementation climate, discuss several measurement issues, and propose guidelines for empirical study. Discussion Implementation climate differs from constructs such as organizational climate, culture, or context in two important respects: first, it has a strategic focus (implementation, and second, it is innovation-specific. Measuring implementation climate is challenging because the construct operates at the organizational level, but requires the collection of multi-dimensional perceptual data from many expected innovation users within an organization. In order to avoid problems with construct validity, assessments of within-group agreement of implementation climate measures must be carefully considered. Implementation climate implies a high degree of within-group agreement in climate perceptions. However, researchers might find it useful to distinguish implementation climate level (the average of implementation climate perceptions from implementation climate strength (the

  12. An ethical response to climate change

    OpenAIRE

    Geoffrey William Lamberton

    2014-01-01

    This paper examines the ethical question of the responsibility of business organisations to respond to climate change. Ethical principles of ‘polluter pays‘, ‘historic culpability’ and ‘equitable distribution of the carbon budget’ are applied to the question of ‘should business respond to climate change’, using rights and utilitarian ethical analyses. An ethical argument is established for business organisations to decarbonise their production and distribution systems rather than delay action...

  13. Managing Climate Change Refugia for Climate Adaptation.

    Science.gov (United States)

    Morelli, Toni Lyn; Daly, Christopher; Dobrowski, Solomon Z; Dulen, Deanna M; Ebersole, Joseph L; Jackson, Stephen T; Lundquist, Jessica D; Millar, Constance I; Maher, Sean P; Monahan, William B; Nydick, Koren R; Redmond, Kelly T; Sawyer, Sarah C; Stock, Sarah; Beissinger, Steven R

    2016-01-01

    Refugia have long been studied from paleontological and biogeographical perspectives to understand how populations persisted during past periods of unfavorable climate. Recently, researchers have applied the idea to contemporary landscapes to identify climate change refugia, here defined as areas relatively buffered from contemporary climate change over time that enable persistence of valued physical, ecological, and socio-cultural resources. We differentiate historical and contemporary views, and characterize physical and ecological processes that create and maintain climate change refugia. We then delineate how refugia can fit into existing decision support frameworks for climate adaptation and describe seven steps for managing them. Finally, we identify challenges and opportunities for operationalizing the concept of climate change refugia. Managing climate change refugia can be an important option for conservation in the face of ongoing climate change. PMID:27509088

  14. Managing Climate Change Refugia for Climate Adaptation

    Science.gov (United States)

    Daly, Christopher; Dobrowski, Solomon Z.; Dulen, Deanna M.; Ebersole, Joseph L.; Jackson, Stephen T.; Lundquist, Jessica D.; Millar, Constance I.; Maher, Sean P.; Monahan, William B.; Nydick, Koren R.; Redmond, Kelly T.; Sawyer, Sarah C.; Stock, Sarah; Beissinger, Steven R.

    2016-01-01

    Refugia have long been studied from paleontological and biogeographical perspectives to understand how populations persisted during past periods of unfavorable climate. Recently, researchers have applied the idea to contemporary landscapes to identify climate change refugia, here defined as areas relatively buffered from contemporary climate change over time that enable persistence of valued physical, ecological, and socio-cultural resources. We differentiate historical and contemporary views, and characterize physical and ecological processes that create and maintain climate change refugia. We then delineate how refugia can fit into existing decision support frameworks for climate adaptation and describe seven steps for managing them. Finally, we identify challenges and opportunities for operationalizing the concept of climate change refugia. Managing climate change refugia can be an important option for conservation in the face of ongoing climate change. PMID:27509088

  15. Natural climate variability and future climate policy

    Science.gov (United States)

    Ricke, Katharine L.; Caldeira, Ken

    2014-05-01

    Large ensemble climate modelling experiments demonstrate the large role natural variability plays in local climate on a multi-decadal timescale. Variability in local weather and climate influences individual beliefs about climate change. To the extent that support for climate mitigation policies is determined by citizens' local experiences, natural variability will strongly influence the timescale for implementation of such policies. Under a number of illustrative threshold criteria for both national and international climate action, we show that variability-driven uncertainty about local change, even in the face of a well-constrained estimate of global change, can potentially delay the time to policy implementation by decades. Because several decades of greenhouse gas emissions can have a large impact on long-term climate outcomes, there is substantial risk associated with climate policies driven by consensus among individuals who are strongly influenced by local weather conditions.

  16. Database application platform for earthquake numerical simulation

    Institute of Scientific and Technical Information of China (English)

    LUO Yan; ZHENG Yue-jun; CHEN Lian-wang; LU Yuan-zhong; HUANG Zhong-xian

    2006-01-01

    @@ Introduction In recent years, all kinds of observation networks of seismology have been established, which have been continuously producing numerous digital information. In addition, there are many study results about 3D velocity structure model and tectonic model of crust (Huang and Zhao, 2006; Huang et al, 2003; Li and Mooney, 1998),which are valuable for studying the inner structure of the earth and earthquake preparation process. It is badly needed to combine the observed data, experimental study and theoretical analyses results by the way of numerical simulation and develop a database and a corresponding application platform to be used by numerical simulation,and is also a significant way to promote earthquake prediction.

  17. Numerical shadow and geometry of quantum states

    Energy Technology Data Exchange (ETDEWEB)

    Dunkl, Charles F [Department of Mathematics, University of Virginia, Charlottesville, VA 22904-4137 (United States); Gawron, Piotr; Miszczak, Jaroslaw A; Puchala, Zbigniew [Institute of Theoretical and Applied Informatics, Polish Academy of Sciences, Baltycka 5, 44-100 Gliwice (Poland); Holbrook, John A [Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Zyczkowski, Karol, E-mail: cfd5z@virginia.edu, E-mail: gawron@iitis.pl, E-mail: jholbroo@uoguelph.ca, E-mail: miszczak@iitis.pl, E-mail: z.puchala@iitis.pl, E-mail: karol@tatry.if.uj.edu.pl [Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland)

    2011-08-19

    The totality of normalized density matrices of dimension N forms a convex set Q{sub N} in R{sup N2-1}. Working with the flat geometry induced by the Hilbert-Schmidt distance, we consider images of orthogonal projections of Q{sub N} onto a two-plane and show that they are similar to the numerical ranges of matrices of dimension N. For a matrix A of dimension N, one defines its numerical shadow as a probability distribution supported on its numerical range W(A), induced by the unitarily invariant Fubini-Study measure on the complex projective manifold CP{sup N-1}. We define generalized, mixed-state shadows of A and demonstrate their usefulness to analyse the structure of the set of quantum states and unitary dynamics therein.

  18. Numerical shadow and geometry of quantum states

    CERN Document Server

    Dunkl, Charles F; Holbrook, John A; Miszczak, Jarosław A; Puchała, Zbigniew; Życzkowski, Karol

    2011-01-01

    The totality of normalised density matrices of order N forms a convex set Q_N in R^(N^2-1). Working with the flat geometry induced by the Hilbert-Schmidt distance we consider images of orthogonal projections of Q_N onto a two-plane and show that they are similar to the numerical ranges of matrices of order N. For a matrix A of a order N one defines its numerical shadow as a probability distribution supported on its numerical range W(A), induced by the unitarily invariant Fubini-Study measure on the complex projective manifold CP^(N-1). We define generalized, mixed-states shadows of A and demonstrate their usefulness to analyse the structure of the set of quantum states and unitary dynamics therein.

  19. Gray wolves as climate change buffers in Yellowstone.

    OpenAIRE

    Wilmers Christopher C; Getz Wayne M

    2005-01-01

    Understanding the mechanisms by which climate and predation patterns by top predators co-vary to affect community structure accrues added importance as humans exert growing influence over both climate and regional predator assemblages. In Yellowstone National Park, winter conditions and reintroduced gray wolves (Canis lupus) together determine the availability of winter carrion on which numerous scavenger species depend for survival and reproduction. As climate changes in Yellowstone, therefo...

  20. Sense in Sensitivity: Assessing Species Vulnerability to Climate Change

    OpenAIRE

    Mcdougall, Amy

    2013-01-01

    This thesis investigates the impact of future climate change upon species vulnerability. Reports of shifts in species distributions are already numerous, but the pattern of change is not fully understood. This thesis looks to predict which species are likely to be most at risk under climate change and why? This thesis takes the equation; Vulnerability= Sensitivity + Exposure to better discover which species are most vulnerable to climate change. Additionally, this research explores how mitiga...

  1. The Earth's Equilibrium Climate Sensitivity and Thermal Inertia

    OpenAIRE

    Royce, B.S.H.; Lam, S H

    2013-01-01

    The Earth's equilibrium climate sensitivity has received much attention because of its relevance and importance for global warming policymaking. This paper focuses on the Earth's \\emph{thermal inertia time scale} which has received relatively little attention. The difference between the observed transient climate sensitivity and the equilibrium climate sensitivity is shown to be proportional to the thermal inertia time scale, and the numerical value of the proportionality factor is determined...

  2. Class Generation for Numerical Wind Atlases

    DEFF Research Database (Denmark)

    Cutler, N.J.; Jørgensen, B.H.; Ersbøll, Bjarne Kjær;

    2006-01-01

    A new optimised clustering method is presented for generating wind classes for mesoscale modelling to produce numerical wind atlases. It is compared with the existing method of dividing the data in 12 to 16 sectors, 3 to 7 wind-speed bins and dividing again according to the stability of the atmos......A new optimised clustering method is presented for generating wind classes for mesoscale modelling to produce numerical wind atlases. It is compared with the existing method of dividing the data in 12 to 16 sectors, 3 to 7 wind-speed bins and dividing again according to the stability...... of the atmosphere. Wind atlases are typically produced using many years of on-site wind observations at many locations. Numerical wind atlases are the result of mesoscale model integrations based on synoptic scale wind climates and can be produced in a number of hours of computation. 40 years of twice daily NCEP...... by optimising the representation of the data and by automating the procedure more. The Karlsruhe Atmospheric Mesoscale Model (KAMM) is combined with the WAsP analysis to produce numerical wind atlases for two sites, Ireland and Egypt. The model results are compared with wind atlases made from measurements...

  3. TRACKING CLIMATE MODELS

    Data.gov (United States)

    National Aeronautics and Space Administration — CLAIRE MONTELEONI*, GAVIN SCHMIDT, AND SHAILESH SAROHA* Climate models are complex mathematical models designed by meteorologists, geophysicists, and climate...

  4. Biomathematical Approach Towards a Linear Climatic Index

    Directory of Open Access Journals (Sweden)

    V. Kumar

    1985-01-01

    Full Text Available The approach is aimed towards integration of major climatic elements for evolving a linear climatic index based on annual averages of three climatic parameters, viz; diurnal range of temperatures, daily mean temperature and precipitation respectively. The index is a measure of aridity of a place, being positive for all arid regions and negative for all humid regions and is effectively applicable to high altitudes. The climatic index, so derived, is termed as 'Linear Aridity Index' and has been compared against Thornthwaite's Moisture Index for 32 meteorological stations in India and neighbourhood (including coastal, non-coastal and high altitude which reveals a close correlation between the two indices. More stations in India and neighbourhood have been analysed in terms of the index value for studying the climatic pattern in India. A nomogram has also been developed for quick evaluation of the index from the given values of the three parameters used.

  5. Can increased organic consumption mitigate climate changes?

    DEFF Research Database (Denmark)

    Heerwagen, Lennart Ravn; Andersen, Laura Mørch; Christensen, Tove;

    2014-01-01

    consumers. As some consumers believe that climate change can be mitigated by consuming organic food, the authors propose that this is taken into account in the development of organic farming. Originality/value – The authors propose a shift from analysing the climate-friendliness of production to addressing......Purpose – The purpose of this paper is to investigate the evidence for a positive correlation between increased consumption of organic products and potential climate change mitigation via decreased consumption of meat and it is discussed to what extent organic consumption is motivated by climate...... correlation between increasing organic budget shares and decreasing meat budget shares is found. People include food-related behaviour such as the purchase of organic food and reduced meat consumption as ways to mitigate climate change. However, other behavioural modifications such as reduction of car usage...

  6. Climate impact from peat utilisation in Sweden

    International Nuclear Information System (INIS)

    The climate impact from the use of peat for energy production in Sweden has been evaluated in terms of contribution to atmospheric radiative forcing. This was done by attempting to answer the question 'What will be the climate impact if one would use 1 m2 of mire for peat extraction during 20 years?'. Two different methods of after-treatment were studied: afforestation and restoration of wetland. The climate impact from a peatland - wetland energy scenario and a peatland - forestry energy scenario was compared to the climate impact from coal, natural gas and forest residues. Sensitivity analyses were performed to evaluate which parameters that are important to take into consideration in order to minimize the climate impact from peat utilisation

  7. Alien Phytogeographic Regions of Southern Africa: Numerical Classification, Possible Drivers, and Regional Threats

    Science.gov (United States)

    Hugo, Sanet; Van Rensburg, Berndt J.; Van Wyk, Abraham E.; Steenkamp, Yolande

    2012-01-01

    The distributions of naturalised alien plant species that have invaded natural or semi-natural habitat are often geographically restricted by the environmental conditions in their new range, implying that alien species with similar environmental requirements and tolerances may form assemblages and characterise particular areas. The aim of this study was to use objective numerical techniques to reveal any possible alien phytogeographic regions (i.e. geographic areas with characteristic alien plant assemblages) in southern Africa. Quarter degree resolution presence records of naturalised alien plant species of South Africa, Lesotho, Swaziland, Namibia and Botswana were analysed through a divisive hierarchical classification technique, and the output was plotted on maps for further interpretation. The analyses revealed two main alien phytogeographic regions that could be subdivided into eight lower level phytogeographic regions. Along with knowledge of the environmental requirements of the characteristic species and supported by further statistical analyses, we hypothesised on the main drivers of alien phytogeographic regions, and suggest that environmental features such as climate and associated biomes were most important, followed by human activities that modify climatic and vegetation features, such as irrigation and agriculture. Most of the characteristic species are not currently well-known as invasive plant species, but many may have potential to become troublesome in the future. Considering the possibility of biotic homogenization, these findings have implications for predicting the characteristics of the plant assemblages of the future. However, the relatively low quality of the dataset necessitates further more in-depth studies with improved data before the findings could be directly beneficial for management. PMID:22574145

  8. Climatic controls on diffuse groundwater recharge across Australia

    Directory of Open Access Journals (Sweden)

    O. V. Barron

    2012-05-01

    Full Text Available Reviews of field studies of groundwater recharge have attempted to investigate how climate characteristics control recharge, but due to a lack of data have not been able to draw any strong conclusions beyond that rainfall is the major determinant. This study has used numerical modeling for a range of Köppen-Geiger climate types (tropical, arid and temperate to investigate the effect of climate variables on recharge for different soil and vegetation types. For the majority of climate types the total annual rainfall had a weaker correlation with recharge than the rainfall parameters reflecting rainfall intensity. In regions with winter-dominated rainfall, annual recharge under the same annual rainfall, soils and vegetation conditions is greater than in regions with summer-dominated rainfall. The relative importance of climate parameters other than rainfall is higher for recharge under annual vegetation, but overall is highest in the tropical climate type. Solar radiation and vapour pressure deficit show a greater relative importance than mean annual daily mean temperature. Climate parameters have lowest relative importance in the arid climate type (with cold winters and the temperate climate type. For 75% of all considered cases of soil, vegetation and climate types recharge elasticity varies between 2 and 4, indicating a 20% to 40% change in recharge for a 10% change in annual rainfall Understanding how climate controls recharge under the observed historical climate allows more informed choices of analogue sites if they are to be used for climate change impact assessments.

  9. Numerical Relativity Beyond Astrophysics

    OpenAIRE

    Garfinkle, David

    2016-01-01

    Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black...

  10. Hybrid undulator numerical optimization

    Energy Technology Data Exchange (ETDEWEB)

    Hairetdinov, A.H. [Kurchatov Institute, Moscow (Russian Federation); Zukov, A.A. [Solid State Physics Institute, Chernogolovka (Russian Federation)

    1995-12-31

    3D properties of the hybrid undulator scheme arc studied numerically using PANDIRA code. It is shown that there exist two well defined sets of undulator parameters which provide either maximum on-axis field amplitude or minimal higher harmonics amplitude of the basic undulator field. Thus the alternative between higher field amplitude or pure sinusoidal field exists. The behavior of the undulator field amplitude and harmonics structure for a large set of (undulator gap)/(undulator wavelength) values is demonstrated.

  11. a numerical study

    OpenAIRE

    Sousa, Antonio C. M.

    2015-01-01

    This paper reports on a numerical study for steady flow and heat transfer distribution for a configuration relevant to Liquid Composite Molding, where agap between a porous substrate and the solid boundary of a mold cavity yieldsan edge flow. The flowwithin the porous domain is modeled by the Brinkman-Forchheimer formulation, and the edge flow itself is described by theNavier-Stokes equations. The cure of the fluid (resin) is simulated as a volumetric heat generation. The predictions are obta...

  12. Handbook of numerical analysis

    CERN Document Server

    Ciarlet, Philippe G

    Mathematical finance is a prolific scientific domain in which there exists a particular characteristic of developing both advanced theories and practical techniques simultaneously. Mathematical Modelling and Numerical Methods in Finance addresses the three most important aspects in the field: mathematical models, computational methods, and applications, and provides a solid overview of major new ideas and results in the three domains. Coverage of all aspects of quantitative finance including models, computational methods and applications Provides an overview of new ideas an

  13. Species distributions and climate change - linking the past and the future

    DEFF Research Database (Denmark)

    Levinsky, Irina

    light on the impact of future climate change on biodiversity. In my PhD, I relate past climatic changes and their impact on the distributions of African birds and mammals to potential impacts of future climate change: I revisit the role of refugia as areas where species survived adverse climatic......Climate change is predicted to have a marked impact on biodiversity, and changes in the distributions of numerous species have already been correlated with ongoing climate change. Climatic oscillations, however, were also the rule during the Pleistocene, and a look to the past may therefore shed...

  14. Use of air/ground heat exchangers for heating and cooling of buildings - in-situ measurements, analytical modeling, numerical simulation and system analysis[Dissertation 3357]; Utilisation des echangeurs air/sol pour le chauffage et le rafraichissement des batiments. Mesures in situ, modelisation analytique, simulation numerique et analyse systemique

    Energy Technology Data Exchange (ETDEWEB)

    Hollmuller, P.

    2002-07-01

    In this thesis, physical properties and practical implementation of air/ground heat exchangers were studied. These exchangers consist in ducts placed in the upper ground layer (up to a depth of several meters). Air is circulated through the ducts, with heat transfer from and to the surrounding earth/sand/gravel material, with heat diffusion (conductive and capacitive effects) through this material. Air/ground heat exchangers are used to preheat or cool the air needed by the ventilation system of a building (open loop systems), or to heat up or cool the air in a greenhouse (closed loop systems). The reported study consisted in: (i) case studies of built examples, by detailed measuring and monitoring and data analysis. (ii) modeling the basic system. (iii) solving the basic equations both numerically (by computerized simulation) and analytically. (iv) identifying the basic features of these systems. (v) establishing recommendations for the practical implementation, especially in what regards sizing. It turned out that daily and seasonal heat storage/delivery by means of an air/ground heat exchanger have to be considered separately, with ad hoc rules of thumb each. Depending on parameter values a phase shift by as much as half the period may even be observed, with very little damping of the temperature oscillation. In Switzerland the main relevance for these systems is for improving thermal comfort in buildings in the summer time when outdoor temperature is higher than 26 {sup o}C, and for damping the amplitude of day/night temperature variations in horticultural greenhouses. The work carried out can be considered as of basic relevance for all applications of the systems studied.

  15. Planetary climates (princeton primers in climate)

    CERN Document Server

    Ingersoll, Andrew

    2013-01-01

    This concise, sophisticated introduction to planetary climates explains the global physical and chemical processes that determine climate on any planet or major planetary satellite--from Mercury to Neptune and even large moons such as Saturn's Titan. Although the climates of other worlds are extremely diverse, the chemical and physical processes that shape their dynamics are the same. As this book makes clear, the better we can understand how various planetary climates formed and evolved, the better we can understand Earth's climate history and future.

  16. Polar ices: rapid climatic changes

    International Nuclear Information System (INIS)

    The recent successes of the European GRIP (GReenland Ice core Project) and American GISP 2 (Greenland Ice Sheet Project) drillings which have reached in 1992 and 1993 the basement rocks of central Greenland (SUMMIT site, 3250 m of altitude) have allow to reconstruct the climate evolution for the last 100,000 years or more. A comparison of climatic informations deduced from these two drillings with records from Vostok (Antarctica) is given in this paper. The δD and δ18O isotopic approach have been used for the reconstruction of climatic series and paleotemperatures in polar regions. Empirical relationships explained by Rayleigh's isotopic models are used as a base for paleotemperature reconstructions from isotopic analyses of ice. A one degree Celsius cooling corresponds to an oxygen 18 decay of 0.67 per thousand and to a 6 per thousand deuterium decay. The GRIP and GISP 2 drillings have demonstrated the exceptional stability of Greenland climate during the last 10.000 years in comparison with strong instabilities encountered during the last 100.000 years and also recorded in North Atlantic marine sediments. The time scales associated with these instabilities are of the order of a few decades for the warming phase. Thanks to Vostok ice-trapped air bubbles analyses, it is now well demonstrated that the strongest instabilities (cooling during the last deglaciation and major glaciation inter stages) are also recorded but less pronounced in Antarctica. GRIP data for the last interglacial stage have been interpreted in terms of climate instabilities but neither GISP 2 results nor Vostok results allow to confirm this interpretation. (J.S.). 29 refs, 3 figs

  17. Numerical Analyses of Thermal Effect of Ventilation on the Surrounding Rock of Shaft in Permafrost regions (Ⅰ) :Airflow Temperature Varying in An Intake Shaft%矿井通风对多年冻土井筒围岩热影响的数值分析(Ⅰ):人风井筒风温的变化规律

    Institute of Scientific and Technical Information of China (English)

    何维维; 盛煜

    2013-01-01

    There are abundant mineral resources in permafrost region of China and the mineral resources exploitation has become one of mainly economic developmental types. As a main resource of energy and raw materials, the mineral resources exploitation promotes economic growth of the western China. However, since the ecosystem of the Qinghai-Tibetan Plateau are very fragile and sensitive to changes in climate and ground surface conditions, a series of environmental geological problems caused by mining resources exploitation, such as the destruction of the ecosystem environment, the destroy of resources and geological hazard. With a large of energy quantity demanded and gradually decreasing of yield of open-pit mining, researches on underground mining are even more badly needed in permafrost region. Based on the relevant research achievements in unfrozen earth area and the meteorological data of Jiangcang coalfield in permafrost area, using calculation program of airflow temperature in an intake shaft, varying law of airflow temperature in an intake shaft was studied by the use of critical temperature. The factors of influencing the airflow temperature were determined and the fitted equation of convection heat transfer boundary conditions between mining ventilation and the surrounding rock of the shaft in permafrost regions was found. The calculation methods and results are given as references for the next study on thermal influence of the surrounding rock of shaft in permafrost regions under the action of mining ventilation.%多年冻土区蕴藏着丰富的矿产资源,矿业开发已成为多年冻土区经济发展的主要产业之一,但是其开采过程将不可避免地受到冻土的影响,也造成多年冻土区生态环境恶化的影响.在西部大开发的进程中,能源需求量逐渐增加,而多年冻土区矿山露天开采量逐渐减少,开展多年冻土区矿山地下开采相关的研究工作显得尤为迫切.基于前人在非冻土区的相关

  18. Report of the workshop on Climate Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The IPCC Working Group I (WGI) held this Workshop on Climate Sensitivity as a major keystone in activities preparing for the WGI contribution to the IPCC Fourth Assessment Report (AR4). One of the most important parameters in climate science is the 'climate sensitivity', broadly defined as the global mean temperature change for a given forcing, often that of a doubling of atmospheric carbon dioxide. Climate sensitivity has played a central role throughout the history of IPCC in interpretation of model outputs, in evaluation of future climate changes expected from various scenarios, and it is closely linked to attribution of currently observed climate changes. An ongoing challenge to models and to climate projections has been to better define this key parameter, and to understand the differences in computed values between various models. Throughout the last three IPCC assessments the climate sensitivity has been estimated as being in the range 1.5 to 4.5 deg. C for CO{sub 2} doubling (i.e., uncertain by a factor of three), making this parameter central to discussions of uncertainty in climate change. The aims of the workshop were to: - Evaluate a range of climate model results so as to relate different climate sensitivity estimates to differences descriptions of physical processes, particularly those related to atmospheric water vapor, clouds, lapse rate changes, ocean heat uptake, treatment of evapotranspiration, land-atmosphere coupling, etc.; - Obtain a more comprehensive picture of the relationships between climate sensitivity and other model features such as resolution, numerical approach, radiative transfer parameters, etc.; - Consider how current, historical, and paleo-climatic data can aid in the determination of the likely range of climate sensitivity; - Improve the understanding of the interpretation and limits of the climate sensitivity concept, including for example possible dependencies upon different forcing agents, predictability questions

  19. Seismic stability analyses - embankment dams

    Energy Technology Data Exchange (ETDEWEB)

    Boudreau, Stephane; Boulanger, Pierre; Caron, Louis Philippe [BPR, Montreal, (Canada); Karray, Mourad [Sherbrooke University, Sherbrooke, (Canada)

    2010-07-01

    An understanding of the effect of earthquakes is necessary to the design of safe dams. A wide number of methods are currently used or being developed for analysing the dynamic slop stability of embankments/dams. This paper investigated the effects of the dynamic aspects (natural period, amplifications and intensity of seismic loading) in the analysis of small dams. A procedure was developed to evaluate the performance of pseudo-static analyses by comparison with fully dynamic analyses. Static, pseudo-static, and dynamic analyses were performed using finite elements and Mohr-Coulomb shear strength criteria. The overall safety factor (FS) was compared using the reduction factor concept. The study worked on two examples of small dams located at moderate and violent seismic regions in the province of Quebec. These examples illustrated the difference between pseudo-static and dynamic analyses. The study also investigated the values of the kh coefficient for Eastern Canada seismicity.

  20. Climate Change: The Physical Basis and Latest Results

    CERN Document Server

    CERN. Geneva

    2009-01-01

    The 2007 Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) concludes: "Warming in the climate system is unequivocal." Without the contribution of Physics to climate science over many decades, such a statement would not have been possible. Experimental physics enables us to read climate archives such as polar ice cores and so provides the context for the current changes. For example, today the concentration of CO2 in the atmosphere, the second most important greenhouse gas, is 28% higher than any time during the last 800,000 years. Classical fluid mechanics and numerical mathematics are the basis of climate models from which estimates of future climate change are obtained. But major instabilities and surprises in the Earth System are still unknown. These are also to be considered when the climatic consequences of proposals for geo-engineering are estimated. Only Physics will permit us to further improve our understanding in order to provide the foundation for policy decisions facing the...

  1. Assessing climate impacts

    OpenAIRE

    Wohl, Ellen E.; Roger S. Pulwarty; Zhang, Jian Yun

    2000-01-01

    Assessing climate impacts involves identifying sources and characteristics of climate variability, and mitigating potential negative impacts of that variability. Associated research focuses on climate driving mechanisms, biosphere–hydrosphere responses and mediation, and human responses. Examples of climate impacts come from 1998 flooding in the Yangtze River Basin and hurricanes in the Caribbean and Central America. Although we have limited understanding of the fu...

  2. Climate Change Schools Project...

    Science.gov (United States)

    McKinzey, Krista

    2010-01-01

    This article features the award-winning Climate Change Schools Project which aims to: (1) help schools to embed climate change throughout the national curriculum; and (2) showcase schools as "beacons" for climate change teaching, learning, and positive action in their local communities. Operating since 2007, the Climate Change Schools Project…

  3. Differences in the climatic debts of birds and butterflies at a continental scale

    NARCIS (Netherlands)

    Devictor, V.; Swaay, van C.; Brereton, T.; Brotons, L.; Chamberlain, D.; Heliölä, J.; Herrando, S.; Julliard, R.; Kuussaari, M.; Lindström, A.; Reif, J.; Roy, D.B.; Schweiger, O.; Settele, J.; Stefanescu, C.; Strien, van A.; Turnhout, van C.; Vermouzek, Z.; Wallis de Vries, M.F.; Wynhoff, I.; Jiguet, F.

    2012-01-01

    Climate changes have profound effects on the distribution of numerous plant and animal species(1-3). However, whether and how different taxonomic groups are able to track climate changes at large spatial scales is still unclear. Here, we measure and compare the climatic debt accumulated by bird and

  4. Numerical differential protection

    CERN Document Server

    Ziegler, Gerhard

    2012-01-01

    Differential protection is a fast and selective method of protection against short-circuits. It is applied in many variants for electrical machines, trans?formers, busbars, and electric lines.Initially this book covers the theory and fundamentals of analog and numerical differential protection. Current transformers are treated in detail including transient behaviour, impact on protection performance, and practical dimensioning. An extended chapter is dedicated to signal transmission for line protection, in particular, modern digital communication and GPS timing.The emphasis is then pla

  5. Hitchhikers’ guide to analysing bird ringing data

    Directory of Open Access Journals (Sweden)

    Harnos Andrea

    2015-12-01

    Full Text Available Bird ringing datasets constitute possibly the largest source of temporal and spatial information on vertebrate taxa available on the globe. Initially, the method was invented to understand avian migration patterns. However, data deriving from bird ringing has been used in an array of other disciplines including population monitoring, changes in demography, conservation management and to study the effects of climate change to name a few. Despite the widespread usage and importance, there are no guidelines available specifically describing the practice of data management, preparation and analyses of ringing datasets. Here, we present the first of a series of comprehensive tutorials that may help fill this gap. We describe in detail and through a real-life example the intricacies of data cleaning and how to create a data table ready for analyses from raw ringing data in the R software environment. Moreover, we created and present here the R package; ringR, designed to carry out various specific tasks and plots related to bird ringing data. Most methods described here can also be applied to a wide range of capture-recapture type data based on individual marking, regardless to taxa or research question.

  6. Developments in numerical ecology

    Energy Technology Data Exchange (ETDEWEB)

    Legendre, P.; Legendre, L.

    1987-01-01

    From earlier ecological studies it has become apparent that simple univariate or bivariate statistics are often inappropriate, and that multivariate statistical analyses must be applied. Despite several difficulties arising from the application of multivariate methods, community ecology has acquired a mathematical framework, with three consequences: it can develop as an exact science; it can be applied operationally as a computer-assisted science to the solution of environmental problems; and it can exchange information with other disciplines using the language of mathematics.

  7. Climate targets and cost-effective climate stabilization pathways

    Science.gov (United States)

    Held, H.

    2015-08-01

    Climate economics has developed two main tools to derive an economically adequate response to the climate problem. Cost benefit analysis weighs in any available information on mitigation costs and benefits and thereby derives an "optimal" global mean temperature. Quite the contrary, cost effectiveness analysis allows deriving costs of potential policy targets and the corresponding cost- minimizing investment paths. The article highlights pros and cons of both approaches and then focusses on the implications of a policy that strives at limiting global warming to 2 °C compared to pre-industrial values. The related mitigation costs and changes in the energy sector are summarized according to the IPCC report of 2014. The article then points to conceptual difficulties when internalizing uncertainty in these types of analyses and suggests pragmatic solutions. Key statements on mitigation economics remain valid under uncertainty when being given the adequate interpretation. Furthermore, the expected economic value of perfect climate information is found to be on the order of hundreds of billions of Euro per year if a 2°-policy were requested. Finally, the prospects of climate policy are sketched.

  8. Climate Networks and Extreme Events

    Science.gov (United States)

    Kurths, J.

    2014-12-01

    We analyse some climate dynamics from a complex network approach. This leads to an inverse problem: Is there a backbone-like structure underlying the climate system? For this we propose a method to reconstruct and analyze a complex network from data generated by a spatio-temporal dynamical system. This approach enables us to uncover relations to global circulation patterns in oceans and atmosphere. The global scale view on climate networks offers promising new perspectives for detecting dynamical structures based on nonlinear physical processes in the climate system. Moreover, we evaluate different regional climate models from this aspect. This concept is also applied to Monsoon data in order to characterize the regional occurrence of extreme rain events and its impact on predictability. Changing climatic conditions have led to a significant increase in magnitude and frequency of spatially extensive extreme rainfall events in the eastern Central Andes of South America. These events impose substantial natural hazards for population, economy, and ecology by floods and landslides. For example, heavy floods in Bolivia in early 2007 affected more than 133.000 households and produced estimated costs of 443 Mio. USD. Here, we develop a general framework to predict extreme events by combining a non-linear synchronization technique with complex networks. We apply our method to real-time satellite-derived rainfall data and are able to predict a large amount of extreme rainfall events. Our study reveals a linkage between polar and subtropical regimes as responsible mechanism: Extreme rainfall in the eastern Central Andes is caused by the interplay of northward migrating frontal systems and a low-level wind channel from the western Amazon to the subtropics, providing additional moisture. Frontal systems from the Antarctic thus play a key role for sub-seasonal variability of the South American Monsoon System.

  9. Climate services to improve public health.

    Science.gov (United States)

    Jancloes, Michel; Thomson, Madeleine; Costa, María Mánez; Hewitt, Chris; Corvalan, Carlos; Dinku, Tufa; Lowe, Rachel; Hayden, Mary

    2014-04-25

    A high level expert panel discussed how climate and health services could best collaborate to improve public health. This was on the agenda of the recent Third International Climate Services Conference, held in Montego Bay, Jamaica, 4-6 December 2013. Issues and challenges concerning a demand led approach to serve the health sector needs, were identified and analysed. Important recommendations emerged to ensure that innovative collaboration between climate and health services assist decision-making processes and the management of climate-sensitive health risk. Key recommendations included: a move from risk assessment towards risk management; the engagement of the public health community with both the climate sector and development sectors, whose decisions impact on health, particularly the most vulnerable; to increase operational research on the use of policy-relevant climate information to manage climate- sensitive health risks; and to develop in-country capacities to improve local knowledge (including collection of epidemiological, climate and socio-economic data), along with institutional interaction with policy makers.

  10. Geopolitics of climate change: A review

    Directory of Open Access Journals (Sweden)

    Bošnjaković Branko

    2012-01-01

    Full Text Available The paper reviews the geopolitical elements of the emerging discourse on how to control, and cope with climate change. Two complementary approaches may be distinguished: the actor-related approach analyses the positioning of states and interest groups, which develop strategies on coping with climate change; the other approach addresses processes and problem areas (physical, economic, demographic… emerging in the geographic space as a consequence of, or linked to climate change. With failing mitigation policies and instruments, the urgency of adaptation to climate change is increasing. Assessment of regional consequences of climate change includes the perceptions and motivations of presumed losers or winners. New security implications related to climate change are emerging in the Arctic, South-East Asia, Africa and the Pacific. Energy supply security is a dominant factor in geopolitical considerations. The geopolitics of climate change is inextricably linked to many other issues of globalization. Significant shift of global power raises the discussion of ethical responsibility. Climate change is evolving as a testing ground for competitiveness and innovation potential of political and economic models in achieving sustainability.

  11. Scaling Climate Change Communication for Behavior Change

    Science.gov (United States)

    Rodriguez, V. C.; Lappé, M.; Flora, J. A.; Ardoin, N. M.; Robinson, T. N.

    2014-12-01

    Ultimately, effective climate change communication results in a change in behavior, whether the change is individual, household or collective actions within communities. We describe two efforts to promote climate-friendly behavior via climate communication and behavior change theory. Importantly these efforts are designed to scale climate communication principles focused on behavior change rather than soley emphasizing climate knowledge or attitudes. Both cases are embedded in rigorous evaluations (randomized controlled trial and quasi-experimental) of primary and secondary outcomes as well as supplementary analyses that have implications for program refinement and program scaling. In the first case, the Girl Scouts "Girls Learning Environment and Energy" (GLEE) trial is scaling the program via a Massive Open Online Course (MOOC) for Troop Leaders to teach the effective home electricity and food and transportation energy reduction programs. The second case, the Alliance for Climate Education (ACE) Assembly Program, is advancing the already-scaled assembly program by using communication principles to further engage youth and their families and communities (school and local communities) in individual and collective actions. Scaling of each program uses online learning platforms, social media and "behavior practice" videos, mastery practice exercises, virtual feedback and virtual social engagement to advance climate-friendly behavior change. All of these communication practices aim to simulate and advance in-person train-the-trainers technologies.As part of this presentation we outline scaling principles derived from these two climate change communication and behavior change programs.

  12. Measure the Climate, Model the City

    Science.gov (United States)

    Boufidou, E.; Commandeur, T. J. F.; Nedkov, S. B.; Zlatanova, S.

    2011-08-01

    Modern large cities are characterized by a high building concentration, little aeration and lack of green spaces. Such characteristics create an urban climate which is different from the climate outside of cities. An example of an urban climate effect is the so-called Urban Heat Island: cities tend to be warmer than the surrounding rural areas. The higher temperature results in an increase in energy consumption since people, especially in summer, use artificial means to cool themselves. Although means of mitigating the UHI effect exist, they are difficult to justify, as knowledge about urban climate is limited, and analysis tools are lacking. This paper presents the work carried during the 2010 MSc Geomatics Synthesis Project. A 3D spatial relational database has been implemented which is meant to act as starting point in the development of a 3D climate-enabled geographical information system. To this end, the database stores 3D geometries representing the built environment and its thematic properties. The database is also able to store measurements of climate parameters, in this case temperature, obtained through mobile sensors. Spatial analyses and queries are supported, allowing users to calculate areas, distances, buffers, add and remove geometries and thematic attributes. The database design is based on the CityGML information model which has been extended to allow the storage of climate parameters relevant to urban climate research.

  13. Building an advanced climate model: Program plan for the CHAMMP (Computer Hardware, Advanced Mathematics, and Model Physics) Climate Modeling Program

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-01

    The issue of global warming and related climatic changes from increasing concentrations of greenhouse gases in the atmosphere has received prominent attention during the past few years. The Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP) Climate Modeling Program is designed to contribute directly to this rapid improvement. The goal of the CHAMMP Climate Modeling Program is to develop, verify, and apply a new generation of climate models within a coordinated framework that incorporates the best available scientific and numerical approaches to represent physical, biogeochemical, and ecological processes, that fully utilizes the hardware and software capabilities of new computer architectures, that probes the limits of climate predictability, and finally that can be used to address the challenging problem of understanding the greenhouse climate issue through the ability of the models to simulate time-dependent climatic changes over extended times and with regional resolution.

  14. Arctic Climate Tipping Points

    OpenAIRE

    Lenton, Timothy M.

    2012-01-01

    There is widespread concern that anthropogenic global warming will trigger Arctic climate tipping points. The Arctic has a long history of natural, abrupt climate changes, which together with current observations and model projections, can help us to identify which parts of the Arctic climate system might pass future tipping points. Here the climate tipping points are defined, noting that not all of them involve bifurcations leading to irreversible change. Past abrupt climate changes in the A...

  15. Cosmic Rays and Climate

    OpenAIRE

    Kirkby, Jasper

    2008-01-01

    Among the most puzzling questions in climate change is that of solar-climate variability, which has attracted the attention of scientists for more than two centuries. Until recently, even the existence of solar-climate variability has been controversial - perhaps because the observations had largely involved temporary correlations between climate and the sunspot cycle. Over the last few years, however, diverse reconstructions of past climate change have revealed clear associations with cosmic...

  16. Mathematics of Climate Change

    OpenAIRE

    Halstadtrø, Ida

    2013-01-01

    Mathematics in climate research is rarely mentioned in the everyday conversations or in the media when talking about climate changes. This thesis therefore focus on the central role mathematics plays in climate research, through describing the different models used in predicting future weather and climate. In Chapter 1, a general introduction to climate, its components and feedbacks, and today's status is given. Chapter 2 concentrates on the dynamical models represented by ordinary differenti...

  17. Confidence in Numerical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    This PowerPoint presentation offers a high-level discussion of uncertainty, confidence and credibility in scientific Modeling and Simulation (M&S). It begins by briefly evoking M&S trends in computational physics and engineering. The first thrust of the discussion is to emphasize that the role of M&S in decision-making is either to support reasoning by similarity or to “forecast,” that is, make predictions about the future or extrapolate to settings or environments that cannot be tested experimentally. The second thrust is to explain that M&S-aided decision-making is an exercise in uncertainty management. The three broad classes of uncertainty in computational physics and engineering are variability and randomness, numerical uncertainty and model-form uncertainty. The last part of the discussion addresses how scientists “think.” This thought process parallels the scientific method where by a hypothesis is formulated, often accompanied by simplifying assumptions, then, physical experiments and numerical simulations are performed to confirm or reject the hypothesis. “Confidence” derives, not just from the levels of training and experience of analysts, but also from the rigor with which these assessments are performed, documented and peer-reviewed.

  18. Numerical wind tunnels

    CERN Document Server

    Souza, Paulo Victor Santos

    2015-01-01

    Flow of viscous fluids are not usually discussed in detail in general and basic courses of physics. This is due in part to the fact that the Navier-Stokes equation has analytical solution only for a few restricted cases, while more sophisticated problems can only be solved by numerical methods. In this text, we present a computer simulation of wind tunnel, i.e., we present a set of programs to solve the Navier-Stokes equation for an arbitrary object inserted in a wind tunnel. The tunnel enables us to visualize the formation of vortices behind object, the so-called von K\\'arm\\'an vortices, and calculate the drag force on the object. We believe that this numerical wind tunnel can support the teacher and allow a more elaborate discussion of viscous flow. The potential of the tunnel is exemplified by the study of the drag on a simplified model of wing whose angle of attack can be controlled. A link to download the programs that make up the tunnel appears at the end.

  19. Feed analyses and their interpretation.

    Science.gov (United States)

    Hall, Mary Beth

    2014-11-01

    Compositional analysis is central to determining the nutritional value of feedstuffs for use in ration formulation. The utility of the values and how they should be used depends on how representative the feed subsample is, the nutritional relevance and analytical variability of the assays, and whether an analysis is suitable to be applied to a particular feedstuff. Commercial analyses presently available for carbohydrates, protein, and fats have improved nutritionally pertinent description of feed fractions. Factors affecting interpretation of feed analyses and the nutritional relevance and application of currently available analyses are discussed.

  20. Randomness and Earth climate variability

    CERN Document Server

    Levinshtein, Michael E; Dmitriev, Alexander P; Shmakov, Pavel M

    2015-01-01

    Paleo-Sciences including palaeoclimatology and palaeoecology have accumulated numerous records related to climatic changes. The researchers have usually tried to identify periodic and quasi-periodic processes in these paleoscientific records. In this paper, we show that this analysis is incomplete. As follows from our results, random processes, namely processes with a single-time-constant (noise with a Lorentzian noise spectrum), play a very important and, perhaps, a decisive role in numerous natural phenomena. For several of very important natural phenomena the characteristic time constants are very similar and equal to (5-8)x10^3 years. However, this value is not universal. For example, the spectral density fluctuations of the atmospheric radiocarbon 14C are characterized by a Lorentzian with time constant 300 years. The frequency dependence of spectral density fluctuations for benthic 18O records contains two Lorentzians with time constans 8000 years and > 105 years.

  1. The carbon rent economics of climate policy

    International Nuclear Information System (INIS)

    By reducing the demand for fossil fuels, climate policy can reduce scarcity rents for fossil resource owners. As mitigation policies ultimately aim to limit emissions, a new scarcity for “space” in the atmosphere to deposit emissions is created. The associated scarcity rent, or climate rent (that is, for example, directly visible in permit prices under an emission trading scheme) can be higher or lower than the original fossil resource rent. In this paper, we analyze analytically and numerically the impact of mitigation targets, resource availability, backstop costs, discount rates and demand parameters on fossil resource rents and the climate rent. We assess whether and how owners of oil, gas and coal can be compensated by a carbon permit grandfathering rule. One important finding is that reducing (cumulative) fossil resource use could actually increase scarcity rents and benefit fossil resource owners under a permit grandfathering rule. For our standard parameter setting overall scarcity rents under climate policy increase slightly. While low discount rates of resource owners imply higher rent losses due to climate policies, new developments of reserves or energy efficiency improvements could more than double scarcity rents under climate policy. Another important implication is that agents receiving the climate rent (regulating institutions or owners of grandfathered permits) could influence the climate target such that rents are maximized, rather than to limit global warming to a socially desirable level. For our basic parameter setting, rents would be maximized at approximately 650 GtC emissions (50% of business-as-usual emissions) implying a virtual certainty of exceeding a 2 °C target and a likelihood of 4 °C warming. - Highlights: • Fossil resource rents form a substantial share of the global GDP. • Fossil resource owners can benefit from climate policy. • Climate targets might be influenced by rent-maximizing aspects

  2. Novethic explains the links between climate and finance

    International Nuclear Information System (INIS)

    The COP 21 conference is the stage for UN climate negotiations among countries and has elicited unprecedented involvement by economic and financial players. For more than a year now, Novethic has been analysing and quantifying the move to incorporate the climate into financial management, a movement that counts nearly 1,000 investors representing Euro 30 trillion. Novethic has prepared four quick guides to ending coal investments, green financing, carbon risk and the climate commitments of the systemic banks and insurance companies

  3. From "Inspiration-driven" Research to "Industrial-strength" Research: Applying User-developed Climate Analytics at Large scale

    Science.gov (United States)

    Radhakrishnan, A.; Mason, E. E.; Langenhorst, A. R.; Balaji, V.; Nikonov, S.

    2014-12-01

    Numerous climate models, several parameters output from a vast range of climate scenarios -- most likely motivates a climate scientist to analyze a suite of available data to research and address a plethora of scientific questions, eg. occurrence of El Niño events or simply validate and compute specialized metrics for a specific climate field. Providing a platform for our scientists to work with data from different models both in-house and extending a similar approach to the application of climate analysis on data from different modeling centers is a key goal that will be addressed in this presentation. Model intercomparison projects, Earth System Grid Federation and knowledge exchange within the climate science community have all enabled successful establishment of "data standards and controlled vocabulary" . This opens key possibilities to facilitate techniques used to "explore" dataset(s) in the Big-Data archive and perform climate analyses following a simple, standardized templated approach. A typical pattern of use would be where the scientist works with a few datasets interactively to refine and extract a signal of a particular climate phenomenon. At this point data access patterns are random, as the analysis is exploratory. We call this the "inspiration-driven" phase of research. Subsequently, the scientist would need to apply her analysis to a much wider set of data: different models and scenarios from CMIP5 for example. This can be thought of as the "industrial" phase of research. We provide a pathway for user-developed analyses to transition from inspiration to industry. We will illustrate techniques being adopted at GFDL to develop analysis through interactive computational exploration on selected data; Provide analysis capabilities in batch workflows (using: Flexible Runtime Environment) and also web-based with data exploration mechanisms tapped from GFDL's Curator infrastructure. Comparing climate data both at the inter and intra-laboratory level

  4. Wavelet-based spatial comparison technique for analysing and evaluating two-dimensional geophysical model fields

    Directory of Open Access Journals (Sweden)

    S. Saux Picart

    2011-11-01

    Full Text Available Complex numerical models of the Earth's environment, based around 3-D or 4-D time and space domains are routinely used for applications including climate predictions, weather forecasts, fishery management and environmental impact assessments. Quantitatively assessing the ability of these models to accurately reproduce geographical patterns at a range of spatial and temporal scales has always been a difficult problem to address. However, this is crucial if we are to rely on these models for decision making. Satellite data are potentially the only observational dataset able to cover the large spatial domains analysed by many types of geophysical models. Consequently optical wavelength satellite data is beginning to be used to evaluate model hindcast fields of terrestrial and marine environments. However, these satellite data invariably contain regions of occluded or missing data due to clouds, further complicating or impacting on any comparisons with the model. A methodology has recently been developed to evaluate precipitation forecasts using radar observations. It allows model skill to be evaluated at a range of spatial scales and rain intensities. Here we extend the original method to allow its generic application to a range of continuous and discontinuous geophysical data fields, and therefore allowing its use with optical satellite data. This is achieved through two major improvements to the original method: (i all thresholds are determined based on the statistical distribution of the input data, so no a priori knowledge about the model fields being analysed is required and (ii occluded data can be analysed without impacting on the metric results. The method can be used to assess a model's ability to simulate geographical patterns over a range of spatial scales. We illustrate how the method provides a compact and concise way of visualising the degree of agreement between spatial features in two datasets. The application of the new method, its

  5. The development of climatic scenarios for Finland

    Energy Technology Data Exchange (ETDEWEB)

    Carter, T.; Tuomenvirta, H. [Finnish Meteorological Inst., Helsinki (Finland); Posch, M. [National Inst. of Public Health and the Environment, Bilthoven (Netherlands)

    1996-12-31

    One of the main objectives of the Finnish Research Programme on Climate Change (SILMU) has been to assess the possible impacts of future changes in climate due to the enhanced greenhouse effect on natural systems and human activities in Finland. In order to address this objective, it was first necessary to specify the types of climate changes to be expected in the Finnish region. Estimates of future climate are conventionally obtained using numerical models, which simulate the evolution of the future climate in response to radiative forcing due to changes in the composition of the atmosphere (i.e. of greenhouse gases and aerosols). However, there are large uncertainties in the model estimates because current knowledge and understanding of atmospheric processes remains incomplete. Since accurate predictions of climate change are not available, an alternative approach is to develop scenarios. These are plausible projections which reflect the best estimates to the future conditions but at the same time embrace the likely uncertainties attached to these estimates. In order to obtain expert opinion on the most appropriate methods of providing scenarios for SILMU, an International Workshop was organised in 1993. The recommendations of the Workshop formed the basis of the present project, initiated in 1994, to develop standard climatic scenarios for Finland

  6. Challenges in bias correcting climate change simulations

    Science.gov (United States)

    Maraun, Douglas; Shepherd, Ted; Zappa, Giuseppe; Gutierrez, Jose; Widmann, Martin; Hagemann, Stefan; Richter, Ingo; Soares, Pedro; Mearns, Linda

    2016-04-01

    Biases in climate model simulations - if these are directly used as input for impact models - will introduce further biases in subsequent impact simulations. In response to this issue, so-called bias correction methods have been developed to post-process climate model output. These methods are now widely used and a crucial component in the generation of high resolution climate change projections. Bias correction is conceptually similar to model output statistics, which has been successfully used for several decades in numerical weather prediction. Yet in climate science, some authors outrightly dismiss any form of bias correction. Starting from this seeming contradiction, we highlight differences between the two contexts and infer consequences and limitations for the applicability of bias correction to climate change projections. We first show that cross validation approaches successfully used to evaluate weather forecasts are fundamentally insufficient to evaluate climate change bias correction. We further demonstrate that different types of model mismatches with observations require different solutions, and some may not sensibly be mitigated. In particular we consider the influence of large-scale circulation biases, biases in the persistence of weather regimes, and regional biases caused by an insufficient representation of the flow-topography interaction. We conclude with a list of recommendations and suggestions for future research to reduce, to post-process, and to cope with climate model biases.

  7. Efficient ALL vs. ALL collision risk analyses

    Science.gov (United States)

    Escobar, D.; Paskowitz, M.; Agueda, A.; Garcia, G.; Molina, M.

    2011-09-01

    In recent years, the space debris has gained a lot of attention due to the increasing amount of uncontrolled man-made objects orbiting the Earth. This population poses a significant and constantly growing thread to operational satellites. In order to face this thread in an independent manner, ESA has launched an initiative for the development of a European SSA System where GMV is participating via several activities. Apart from those activities financed by ESA, GMV has developed closeap, a tool for efficient conjunction assessment and collision probability prediction. ESÁs NAPEOS has been selected as computational engine and numerical propagator to be used in the tool, which can be considered as an add-on to the standard NAPEOS package. closeap makes use of the same orbit computation, conjunction assessment and collision risk algorithms implemented in CRASS, but at the same time both systems are completely independent. Moreover, the implementation in closeap has been validated against CRASS with excellent results. This paper describes the performance improvements implemented in closeap at algorithm level to ensure that the most time demanding scenarios (e.g., all catalogued objects are analysed against each other - all vs. all scenarios -) can be analysed in a reasonable amount of time with commercial-off-the-shelf hardware. However, the amount of space debris increases steadily due to the human activities. Thus, the number of objects involved in a full collision assessment is expected to increase notably and, consequently, the computational cost, which scales as the square of the number of objects, will increase as well. Additionally, orbit propagation algorithms that are computationally expensive might be needed to predict more accurately the trajectories of the space debris. In order to cope with such computational needs, the next natural step in the development of collision assessment tools is the use of parallelization techniques. In this paper we investigate

  8. Funding climate adaptation strategies with climate derivatives

    Directory of Open Access Journals (Sweden)

    L. Richard Little

    2015-01-01

    Full Text Available Climate adaptation requires large capital investments that could be provided not only by traditional sources like governments and banks, but also by derivatives markets. Such markets would allow two parties with different tolerances and expectations about climate risks to transact for their mutual benefit and, in so doing, finance climate adaptation. Here we calculate the price of a derivative called a European put option, based on future sea surface temperature (SST in Tasmania, Australia, with an 18 °C strike threshold. This price represents a quantifiable indicator of climate risk, and forms the basis for aquaculture industries exposed to the risk of higher SST to finance adaptation strategies through the sale of derivative contracts. Such contracts provide a real incentive to parties with different climate outlooks, or risk exposure to take a market assessment of climate change.

  9. Attitude stability analyses for small artificial satellites

    International Nuclear Information System (INIS)

    The objective of this paper is to analyze the stability of the rotational motion of a symmetrical spacecraft, in a circular orbit. The equilibrium points and regions of stability are established when components of the gravity gradient torque acting on the spacecraft are included in the equations of rotational motion, which are described by the Andoyer's variables. The nonlinear stability of the equilibrium points of the rotational motion is analysed here by the Kovalev-Savchenko theorem. With the application of the Kovalev-Savchenko theorem, it is possible to verify if they remain stable under the influence of the terms of higher order of the normal Hamiltonian. In this paper, numerical simulations are made for a small hypothetical artificial satellite. Several stable equilibrium points were determined and regions around these points have been established by variations in the orbital inclination and in the spacecraft principal moment of inertia. The present analysis can directly contribute in the maintenance of the spacecraft's attitude

  10. Digital analyses of cartometric Fruska Gora guidelines

    Directory of Open Access Journals (Sweden)

    Živković Dragica

    2013-01-01

    Full Text Available Modern geo morphological topography research have been using quantity statistic and cartographic methods for topographic relief features, mutual relief features, mutual connection analyses on the grounds of good quality numeric parameters etc. Topographic features are important for topographic activities are important for important natural activities. Important morphological characteristics are precisely at the angle of topography, hypsometry, and topography exposition and so on. Small yet unknown relief slants can deeply affect land configuration, hypsometry, topographic exposition etc. Expositions modify the light and heat of interconnected phenomena: soil and air temperature, soil disintegration, the length of vegetation period, the complexity of photosynthesis, the fruitfulness of agricultural crops, the height of snow limit etc. [Projekat Ministarstva nauke Republike Srbije, br. 176008 i br. III44006

  11. The German contribution to the global forest policy. Analysis and evaluation of the engagement for biodiversity conservation and mitigation measures climatic change; Der deutsche Beitrag zur globalen Waldpolitik. Analyse und Bewertung des Engagements zum Erhalt der Biodiversitaet und zur Eindaemmung des Klimawandels

    Energy Technology Data Exchange (ETDEWEB)

    Busch, Anika

    2013-07-01

    The booklet on the German contribution to the global forest policy covers with analysis and evaluation of the engagement for biodiversity conservation and mitigation measures climatic change. The analysis is based on expert interviews; the theoretical background is the conception on society by Niklas Lehmann. The evaluation includes the issues of allocation of public goods, the improvement of public participation, and improvement of financing resources.

  12. FLUCTUATION EFFECT OF EQUILIBRIUM MOISTURE CONTENT OF LOW SUBGRADE UNDER HIGH GROUNDWATER LEVEL IN HOT AND HUMID CLIMATIC REGIONS

    Directory of Open Access Journals (Sweden)

    Que Yun

    2016-05-01

    Full Text Available In order to reveal the fluctuation effect of equilibrium moisture content of low subgrade in hot and humid climatic regions, the effect of temperature on the fluctuation of the equilibrium moisture content of subgrade was analysed. Taking the typical climate and the subgrade soil in Fujian province as an example, three technological methods - theoretical analysis, numerical simulation and indoor simulation experiment - were adopted in the investigation of the fluctuation effect of equilibrium moisture content of subgrade. The results show that, computing results from the formula of the equilibrium moisture content of subgrade, the numerical simulation results are closer to each other in consideration of the temperature effect. The test results can not reflect the relationship between the equilibrium moisture content and the height of embankment. The maximum fluctuation range of the equilibrium moisture content of the cement concrete pavement is less than 2 percent in Fujian area, and this phenomenon presents the effect of the moist-hot climate on the equilibrium moisture content. Equilibrium moisture content presents a declining trend with the increment of the temperature and the compactness. So, if matric potential considering temperature indirectly reflects the influence of thermal potential, then the equilibrium moisture content of low subgrade under high groundwater level can be estimated approximately. The fluctuation range of equilibrium moisture content in different layers of subgrade can be reduced effectively with the increment of the roadbed compaction degree.

  13. Conjoint-Analyse und Marktsegmentierung

    OpenAIRE

    Steiner, Winfried J.; Baumgartner, Bernhard

    2003-01-01

    Die Marktsegmentierung zählt neben der Neuproduktplanung und Preisgestaltung zu den wesentlichen Einsatzgebieten der Conjoint-Analyse. Neben traditionell eingesetzten zweistufigen Vorgehensweisen, bei denen Conjoint-Analyse und Segmentierung in zwei getrennten Schritten erfolgen, stehen heute mit Methoden wie der Clusterwise Regression oder Mixture-Modellen neuere Entwicklungen, die eine simultane Segmentierung und Präferenzschätzung ermöglichen, zur Verfügung. Der Beitrag gibt einen Überblic...

  14. 3D Geo-Information in Urban Climate Studies

    Science.gov (United States)

    Petrescu, F.; Aldea, M.; Luca, O.; Iacoboaea, C.; Gaman, F.; Parlow, E.

    2016-10-01

    3D geo-information is essential for urban climate studies. It is obvious that both natural environment and built-up environment play the fundamental role in defining the climatic conditions for urban areas, which affect the quality of human life and human comfort. The paper presents the main categories of 3D geo-information used in urban climate studies and roles in creating and operating the numerical models specially designed to simulate urban planning scenarios and improvement of the urban climate situation.

  15. Global water resources affected by human interventions and climate change

    NARCIS (Netherlands)

    Haddeland, I.; Heinke, J.; Biemans, H.; Eisner, S.; Flörke, M.; Hanasaki, N.; Konzmann, M.; Ludwig, F.; Masaki, Y.; Schewe, J.; Stacke, T.; Tessler, Z.; Wada, Y.; Wisser, D.

    2014-01-01

    Humans directly change the dynamics of the water cycle through dams constructed for water storage, and through water withdrawals for industrial, agricultural, or domestic purposes. Climate change is expected to additionally affect water supply and demand. Here, analyses of climate change and direct

  16. Global water resources affected by human interventionss and climate change

    NARCIS (Netherlands)

    Haddeland, I.; Heinke, J.; Biemans, H.; Eisner, S.; Florke, M.F.; Hanasaki, N.; Konzmann, M.; Ludwig, F.

    2014-01-01

    Humans directly change the dynamics of the water cycle through dams constructed for water storage, and through water withdrawals for industrial, agricultural, or domestic purposes. Climate change is expected to additionally affect water supply and demand. Here, analyses of climate change and direct

  17. Global imprint of climate change on marine life

    DEFF Research Database (Denmark)

    Poloczanska, Elvira S.; Brown, Christopher J.; Sydeman, William J.;

    2013-01-01

    Past meta-analyses of the response of marine organisms to climate change have examined a limited range of locations1,2, taxonomic groups2–4 and/or biological responses5,6. This has precluded a robust overview of the effect of climate change in the global ocean. Here, we synthesized all available ...

  18. Climate change ethics, rights, and policies: an introduction

    NARCIS (Netherlands)

    Barry, J.; Mol, A.P.J.; Zito, A.R.

    2013-01-01

    Climate change continues to dominate academic work within green/environmental politics. Indeed, there appears to be almost an inverse relationship between the lack of political leadership on tackling climate change and the growth in ever more sophisticated academic analyses of this complex and multi

  19. The stability likelihood of an international climate agreement

    NARCIS (Netherlands)

    Dellink, R.B.; Finus, M.; Olieman, N.J.

    2008-01-01

    Results derived from empirical analyses on the stability of climate coalitions are usually very sensitive to the large uncertainties associated with the benefits and costs of climate policies. This paper provides the methodology of Stability Likelihood (SL) that links uncertainties about benefits an

  20. Track 3: growth of nuclear technology and research numerical and computational aspects of the coupled three-dimensional core/plant simulations: organization for economic cooperation and development/U.S. nuclear regulatory commission pressurized water reactor main-steam-line-break benchmark-I. 5. Analyses of the OECD MSLB Benchmark with the Codes DYN3D and DYN3D/ATHLET

    International Nuclear Information System (INIS)

    The code DYN3D coupled with ATHLET was used for the analysis of the OECD Main-Steam-Line-Break (MSLB) Benchmark, which is based on real plant design and operational data of the TMI-1 pressurized water reactor (PWR). Like the codes RELAP or TRAC,ATHLET is a thermal-hydraulic system code with point or one-dimensional neutron kinetic models. ATHLET, developed by the Gesellschaft for Anlagen- und Reaktorsicherheit, is widely used in Germany for safety analyses of nuclear power plants. DYN3D consists of three-dimensional nodal kinetic models and a thermal-hydraulic part with parallel coolant channels of the reactor core. DYN3D was coupled with ATHLET for analyzing more complex transients with interactions between coolant flow conditions and core behavior. It can be applied to the whole spectrum of operational transients and accidents, from small and intermediate leaks to large breaks of coolant loops or steam lines at PWRs and boiling water reactors. The so-called external coupling is used for the benchmark, where the thermal hydraulics is split into two parts: DYN3D describes the thermal hydraulics of the core, while ATHLET models the coolant system. Three exercises of the benchmark were simulated: Exercise 1: point kinetics plant simulation (ATHLET) Exercise 2: coupled three-dimensional neutronics/core thermal-hydraulics evaluation of the core response for given core thermal-hydraulic boundary conditions (DYN3D) Exercise 3: best-estimate coupled core-plant transient analysis (DYN3D/ATHLET). Considering the best-estimate cases (scenarios 1 of exercises 2 and 3), the reactor does not reach criticality after the reactor trip. Defining more serious tests for the codes, the efficiency of the control rods was decreased (scenarios 2 of exercises 2 and 3) to obtain recriticality during the transient. Besides the standard simulation given by the specification, modifications are introduced for sensitivity studies. The results presented here show (a) the influence of a reduced