WorldWideScience

Sample records for climate numerical analyses

  1. 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

    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.......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...

  2. 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:

  3. 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.

  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.

  5. 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.

  6. Some numerical analyses of flows with separation

    Science.gov (United States)

    Kuwahara, K.

    Computational study of high Reynolds number flow with large separation is the most important problem now in computational aerodynamics. Some examples of recent results of studies of such flows are presented. The methods used are finite-difference methods and vortex methods. The first example is that of an incompressible flow past two cylinders computed by the finite-difference method based on a stream function-vorticity formulation of the Navier-Stokes equations. It is pointed out that special care must be taken to determine the boundary values of the stream function on the bodies when using this method. The second example is that of an incompressible flow past a circular cylinder at a critical Reynolds number computed by the MAC method using an improved upwind difference. The sharp drag reduction is first captured numerically by this computation. Third is an example of the simplest version of the new vortex methods without conformal mapping, which enables us to compute incompressible flows with large separation very easily and economically. The last example is of a transonic flow past an oscillating airfoil computed by the Beam-Warming scheme.

  7. 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

  8. 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.``

  9. Historical Phenological Observations: Past Climate Impact Analyses and Climate Reconstructions

    Science.gov (United States)

    Rutishauser, T.; Luterbacher, J.; Meier, N.; Jeanneret, F.; Pfister, C.; Wanner, H.

    2007-12-01

    Plant phenological observations have been found an important indicator of climate change impacts on seasonal and interannual vegetation development for the late 20th/early 21st century. Our contribution contains three parts that are essential for the understanding (part 1), the analysis (part 2) and the application (part 3) of historical phenological observations in global change research. First, we propose a definition for historical phenonolgy (Rutishauser, 2007). We shortly portray the first appearance of phenological observations in Medieval philosophical and literature sources, the usage and application of this method in the Age of Enlightenment (Carl von Linné, Charles Morren), as well as the development in the 20th century (Schnelle, Lieth) to present-day networks (COST725, USA-NPN) Second, we introduce a methodological approach to estimate 'Statistical plants' from historical phenological observations (Rutishauser et al., JGR-Biogeoscience, in press). We combine spatial averaging methods and regression transfer modeling to estimate 'statistical plant' dates from historical observations that often contain gaps, changing observers and changing locations. We apply the concept to reconstruct a statistical 'Spring plant' as the weighted mean of the flowering date of cherry and apple tree and beech budburst of Switzerland 1702- 2005. Including dating total data uncertainty we estimate 10 at interannual and 3.4 days at decadal time scales. Third, we apply two long-term phenological records to describe plant phenological response to spring temperature and reconstruct warm-season temperatures from grape harvest dates (Rutishauser et al, submitted; Meier et al, GRL, in press).

  10. 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.

  11. 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.

  12. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Auffhammer, M.; Hsiang, S. M.; Schlenker, W.; Sobel, A.

    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.

  14. Experimental and numerical analyses of magnesium alloy hot workability

    Directory of Open Access Journals (Sweden)

    F. Abbassi

    2016-12-01

    Full Text Available Due to their hexagonal crystal structure, magnesium alloys have relatively low workability at room temperature. In this study, the hot workability behavior of cast-extruded AZ31B magnesium alloy is studied through hot compression testing, numerical modeling and microstructural analyses. Hot deformation tests are performed at temperatures of 250 °C to 400 °C under strain rates of 0.01 to 1.0 s−1. Transmission electron microscopy is used to reveal the presence of dynamic recrystallization (DRX, dynamic recovery (DRY, cracks and shear bands. To predict plastic instabilities during hot compression tests of AZ31B magnesium alloy, the authors use Johnson–Cook damage model in a 3D finite element simulation. The optimal hot workability of magnesium alloy is found at a temperature (T of 400 °C and strain rate (ε˙ of 0.01 s−1. Stability is found at a lower strain rate, and instability is found at a higher strain rate.

  15. 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

  16. ANALYSES OF LANDSCAPE GEOGRAPHIC IMPACTS OF POTENTIAL CLIMATE CHANGE IN HUNGARY

    Directory of Open Access Journals (Sweden)

    PÉTER CSORBA

    2012-06-01

    Full Text Available Change of climate can be a remarkable turning point in the 21st century history of mankind. An important task of landscape geographic research is forecasting environmental, nature protection, land use demands and helping mitigation of disadvantageous processes from the aspect of society. ALADIN and REMO numeric climate models predict strong warming and lack of summer precipitation for the area of Hungary for the period between 2021 and 2100. There is a predictedgrowth in frequency of extreme weather events (heat waves, droughts hailstorms. Changes have been forecasted using data presented in table 1. For analyses of complex landscape geographic impacts ofclimate change the area of Hungary have been divided into 18 mesoregions with 5.000-10.000 km2 area each (figure 1. The main aspect of choosing the regions was that they should have homogeneousphysical, geographic and land use endowments and, for this reason, they should react to climate change the same way. Relationships between landscape forming factors and meteorological elementsexamined by us have been taken into consideration. Results of analyses of impacts of the meteorological factors on the changes of relief through the mass movements are presented in this paper. Changes of landscape sensibility of mesoregions to mass movements have been presented in the last chapter for the periods between 2021-2050 and 2071-2100 according to numeric climate models.

  17. 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.

  18. 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

  19. 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...... analysis. In order to evaluate and refine the model parameters for the thermal analysis, the numerical results from this analysis are compared with experimental measurements of the temperature. To evaluate the predicted stress/strain fields, the mechanical model has been validated experimentally. This has...

  20. 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.

  1. Use of EBSD data in mesoscale numerical analyses

    Energy Technology Data Exchange (ETDEWEB)

    Becker, R; Wiland, H

    2000-03-30

    EBSD and FEM studies will provide impetus for further development of microstructure models and theories of microstructure evolution. Early studies connecting EBSD data to detailed finite element models used manual measurements to define initial orientations for the simulations. In one study, manual measurements of the deformed structure were also obtained for comparison with the model predictions. More recent work has taken advantage of automated data collection on deformed specimens as a means of collecting detailed and spatially correlated data for FEM model validation. Although it will not be discussed here, EBSD data can also be incorporated in FEM analyses in a less direct manner that is suitable for simulations where the element size is much larger than the grain size. The purpose of such models is to account for the effects of evolving material anisotropy in macro-scale simulations. In these analyses, a polycrystal plasticity model (e.g., a Taylor model or a self-consistent model), or a yield surface constructed from a polycrystal plasticity model, is used to determine the constitutive response of each element. The initial orientations used in the polycrystal plasticity model can be obtained from EBSD analyses or by fitting distributions of discrete orientations to x-ray data. The use of EBSD data is advantageous in that it is easier to account for spatial gradients of orientation distribution within a part. Another area in which EBSD data is having a great impact is on recrystallization modeling. EBSD techniques can be used to collect data for quantitative microstructural analysis (Humphreys, 1998). This data can be used to infer growth kinetics of specific orientations, and this information can be synthesized into more accurate grain growth or recrystallization models (Vogel et al., 1996). A second role which EBSD techniques may play in recrystallization modeling is in determining initial structures for the models. A realistic starting structure is vital for

  2. Numerical Modeling of Climate-Chemistry Connections: Recent Developments and Future Challenges

    Directory of Open Access Journals (Sweden)

    Patrick Jöckel

    2013-05-01

    Full Text Available This paper reviews the current state and development of different numerical model classes that are used to simulate the global atmospheric system, particularly Earth’s climate and climate-chemistry connections. The focus is on Chemistry-Climate Models. In general, these serve to examine dynamical and chemical processes in the Earth atmosphere, their feedback, and interaction with climate. Such models have been established as helpful tools in addition to analyses of observational data. Definitions of the global model classes are given and their capabilities as well as weaknesses are discussed. Examples of scientific studies indicate how numerical exercises contribute to an improved understanding of atmospheric behavior. There, the focus is on synergistic investigations combining observations and model results. The possible future developments and challenges are presented, not only from the scientific point of view but also regarding the computer technology and respective consequences for numerical modeling of atmospheric processes. In the future, a stronger cross-linkage of subject-specific scientists is necessary, to tackle the looming challenges. It should link the specialist discipline and applied computer science.

  3. Advances and Challenges in Numerical Weather and Climate Prediction

    Science.gov (United States)

    Yu, Tsann-Wang

    2010-10-01

    In this review article, the dispersive nature of various waves that exist in the atmosphere is first reviewed. These waves include Rossby waves, Kelvin wave, acoustic wave, internal and external gravity waves and many others, whose intrinsic nature and great relevancy to weather and climate forecasts are described. This paper then describes the latest development in global observations and data analysis and assimilation methodologies. These include three-dimensional and four dimensional variational data assimilation systems that are being used in the world's major operational weather and climate forecasting centers. Some of the recent results in using novel atmospheric satellite and chemical observation data applied to these data assimilation systems and those from the latest development in high resolution modeling and the ensemble forecasting approach in the operational numerical weather forecasting centers are also presented. Finally, problems of inherent errors associated with initial conditions, and those associated with the coupling of dynamics and physics and their related numerical issues in variational data assimilation systems are discussed.

  4. Analysing responses to climate change through the lens of reflexivity.

    Science.gov (United States)

    Davidson, Debra

    2012-12-01

    Sociologists are increasingly directing attention toward social responses to climate change. As is true of any new field of inquiry, theoretical frameworks guiding the research to date have room for improvement. One advance could be achieved through closer engagement with Reflexivity Theory, particularly the work of Margaret Archer, who asks just how individuals come to give attention to certain problems, and formulate responses to them. Individuals vary significantly in regard to their understanding of and concern for anthropogenic climate change, and these standpoints in turn influence commitment to mitigation and adaptation. The emergent social interactions among all such agents in turn influence the morphogenetic trajectories through which social structures will evolve, but the role of 'meta-reflexives' is particularly crucial. Identifying pathways of individual climate change reflexivity can make a valuable contribution to our understanding of the potential for and nature of collective responses. In this paper, I explore climate change reflexivity, with particular attention to climate change meta-reflexives, through a qualitative analysis of personal interviews with residents of two small communities in Alberta, Canada. Applying Reflexivity Theory to this context articulates dimensions of reflexive processing not elaborated in current theoretical treatments, including future outlook and comfort with uncertainty, among others.

  5. 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

  6. Notes of Numerical Simulation of Summer Rainfall in China with a Regional Climate Model REMO

    Institute of Scientific and Technical Information of China (English)

    CUI Xuefeng; HUANG Gang; CHEN Wen

    2008-01-01

    Regional climate models are major tools for regional climate simulation and their output are mostly used for climate impact studies. Notes are reported from a series of numerical simulations of summer rainfall in China with a regional climate model. Domain sizes and running modes are major foci. The results reveal that the model in forecast mode driven by "perfect" boundaries could reasonably represent the inter-annual differences: heavy rainfall along the Yangtze River in 1998 and dry conditions in 1997. Model simulation in climate mode differs to a greater extent from observation than that in forecast mode. This may be due to the fact that in climate mode it departs further from the driving fields and relies more on internal model dynamical processes. A smaller domain in climate mode outperforms a larger one. Further development of model parameterizations including dynamic vegetation are encouraged in future studies.

  7. Computational model for supporting SHM systems design: Damage identification via numerical analyses

    Science.gov (United States)

    Sartorato, Murilo; de Medeiros, Ricardo; Vandepitte, Dirk; Tita, Volnei

    2017-02-01

    This work presents a computational model to simulate thin structures monitored by piezoelectric sensors in order to support the design of SHM systems, which use vibration based methods. Thus, a new shell finite element model was proposed and implemented via a User ELement subroutine (UEL) into the commercial package ABAQUS™. This model was based on a modified First Order Shear Theory (FOST) for piezoelectric composite laminates. After that, damaged cantilever beams with two piezoelectric sensors in different positions were investigated by using experimental analyses and the proposed computational model. A maximum difference in the magnitude of the FRFs between numerical and experimental analyses of 7.45% was found near the resonance regions. For damage identification, different levels of damage severity were evaluated by seven damage metrics, including one proposed by the present authors. Numerical and experimental damage metrics values were compared, showing a good correlation in terms of tendency. Finally, based on comparisons of numerical and experimental results, it is shown a discussion about the potentials and limitations of the proposed computational model to be used for supporting SHM systems design.

  8. Static and modal numerical analyses for the roof structure of a railway freight refrigerated car

    Directory of Open Access Journals (Sweden)

    Raffaele Sepe

    2015-07-01

    Full Text Available Numerical analyses by finite element method and experimental tests are used to determine static and dynamic behaviour of railway vehicles. Experimental measurements are very time consuming and expensive, so they cannot be used at all stages of design. Numerical simulations do not have the disadvantages of experimental methods, but it is necessary to verify them by experiments to obtain realistic results. Fullwidth/ full-length, half-width/full-length and half-width/half-length modeling approaches can be used to determine static and vibrational behaviours of railway vehicles depending or not on the symmetry of roof structure and applied load. Different static loading cases defined in standards such as EN 12663, UIC CODE OR 577 and ERRI B12/RP17 have to be considered in FE analyses. Evaluation of stress states, buckling and vibrational behaviours for a roof structure of a railway freight refrigerated car are presented. To highlight the vibrational behaviour of the structure normal mode (free vibration analyses are performed. As a result of the relevant simulations, structural characteristics and structural weaknesses of the design are determined.

  9. 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 the fully non-linear regime down-drift spits and migrating shoreline undulations are described.Three different shoreline shapes are found depending on the wave conditions: undulations with no spits, undulations with shore parallel spit and undulations with reconnecting spits. © 2012 Published by Elsevier B.V....

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nikolowski, Johannes; Zimm, Jakob; Naumann, Thomas [Leibniz Institute of Ecological Urban and Regional Development, Dresden (Germany); Goldberg, Valeri [Technische Univ. Dresden (Germany). Chair of Meteorology

    2013-04-15

    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. (orig.)

  12. ANALYSES OF ERRORS IN MEDIUM-TERM NUMERICAL FORECAST PRODUCTS FOR THE SUBTROPICAL HIGH 1998

    Institute of Scientific and Technical Information of China (English)

    王兴荣; 姚叶青; 尚瑜; 陈晓平; 程小泉; 率爱梅

    2003-01-01

    By statistic and dynamic analyses, we have come to the following concl usions: (1) The ECMWF medium-term numerical forecast can forecast medium-term ac tivity of subtropical high, and the accuracy rate of forecast cannot have large improvement by translational corrections. (2) The important cause for the ECMWF medium-term numerical forecast to have errors in 1998 is that the astronomical t ide is not included in the model. (3) Two indexes are found from which it can be judged that ECMWF medium-term numerical forecast will have errors if the astro nomical tide is ignored in the model : ① When the 54.7° line under the moon of the nodical month astronomical singularities coincides with the trough-line of the subtropical jet flow from 50°E to 150°E on the 500 hPa level at 2000 L.T. of the same day, and is approximately vertical (α>60°) with the isotherm, then the day 0 - 2 days after the appearance of the nodical month astronomical singu larities is defined as the initial day. Then in three successive days after the initial day, ECMWF medium-term numerical forecast of the northern latitude of th e 588 line at 120 °E will have continuous errors as large as two latitudes (7/9 ). Otherwise, it won't have continuous errors (13/13). ② Otherwise, if the 54.7 ° line is in the range of a low pressure between two high pressures, then ther e is a dispersive error on the day of the nodical month astronomical singulariti es (5/7). There is not any error (6/6) otherwise.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. Reproductive mode evolution in lizards revisited: updated analyses examining geographic, climatic and phylogenetic effects support the cold-climate hypothesis.

    Science.gov (United States)

    Watson, C M; Makowsky, R; Bagley, J C

    2014-12-01

    Viviparity, the bearing of live young, has evolved well over 100 times among squamate reptiles. This reproductive strategy is hypothesized to allow maternal control of the foetus' thermal environment and thereby to increase the fitness of the parents and offspring. Two hypotheses have been posited to explain this phenomenon: (i) the cold-climate hypothesis (CCH), which advocates low temperatures as the primary selective force; and (ii) the maternal manipulation hypothesis (MMH), which advocates temperature variability as the primary selective force. Here, we investigate whether climatic and geographic variables associated with the CCH vs. the MMH best explain the current geographical distributions of viviparity in lizards while incorporating recent advances in comparative methods, squamate phylogenetics and geospatial analysis. To do this, we compared nonphylogenetic and phylogenetic models predicting viviparity based on point-of-capture data from 20,994 museum specimens representing 215 lizard species in conjunction with spatially explicit bioclimatic and geographic (elevation and latitude) data layers. The database we analysed emphasized Nearctic lizards from three species-rich genera (Phrynosoma, Plestiodon and Sceloporus); however, we additionally analysed a less substantial, but worldwide sample of species to verify the universality of our Nearctic results. We found that maximum temperature of the warmest month (and, less commonly, elevation and maximum temperature of the driest quarter) was frequently the best predictor of viviparity and showed an association consistent with the CCH. Our results strongly favour the CCH over the MMH in explaining lizard reproductive mode evolution.

  18. 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.

  19. 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.

  20. 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.

  1. Experimental and numerical evaluation of a solar passive cooling system under hot and humid climatic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rincon, Jose; Almao, Nastia [Universidad del Zulia, Lab. de Simulacion Computacional, Zulia (Venezuela); Gonzalez, Eduardo [Universidad del Zulia, Inst. de Investigaciones de la Facultad de Arquitectura, Zulia (Venezuela)

    2001-07-01

    The thermal performance of a solar passive cooling system (SPCS) under a hot and humid climate is experimentally and numerically evaluated. The experimental data were obtained from two full scale cells, with identical walls, but different roof configurations. One cell has a highly-insulated roof and the other has an SPCS incorporated consisting of a thermal mass (water), which is cooled by evaporation and long wave nocturnal radiation. The study was conducted taking into account the local climatic conditions of Maracaibo, a tropical city located in Venezuela. The numerical evaluation was accomplished using the computational code 'EVITA' which is based on the finite volume approach with high order bounded treatment of the convective terms. A PISO-like solution algorithm is used to solve the transient form of the continuity, momentum and energy equations. It has been demonstrated experimentally and numerically that under a hot and humid climate, it is possible to keep the indoor temperature below the outdoor temperature, using a passive cooling technique of a roof pond. The numerical results obtained using the model have demonstrated that the computational code used is a suitable cost-efficient alternative for the thermal performance evaluation of SPCS. (Author)

  2. Numerical analyses of high Reynolds number flow of high pressure fuel gas through rough pipes

    Energy Technology Data Exchange (ETDEWEB)

    Cadorin, Margherita; Morini, Mirko; Pinelli, Michele [ENDIF - Engineering Department in Ferrara, University of Ferrara, Via Saragat, 1 - 44122 Ferrara (Italy)

    2010-07-15

    In this paper, a CFD commercial code is used to evaluate the pressure drop through pipes in a stream of high pressure gas. Both hexahedral and tetrahedral grids are considered. Preliminarily, a grid sensitivity analysis is carried out by comparing CFD results with analytical results. Each grid is characterized by a different number and thickness of layers in order to investigate the behavior of the grid with respect to the boundary layer. Then, the model is validated by using a literature test case, in which high pressure gas flow through a rough pipe is experimentally studied. Moreover, various equations of state (i.e., constant properties, Ideal Gas and Redlich-Kwong equations) and boundary conditions (e.g., pressure, mass flow, etc.) are taken into consideration and compared. Finally, the model is used to extrapolate the behavior of gaseous fuels (i.e., natural gas, biogas and hydrogen-methane mixture) flowing at high pressure through pipes of different roughness. The analyses show that the radial depth of the prism layers on pipe wall has to be controlled to allow the correct resolution of the boundary layer. Moreover, the results highlight that the first element height of the prism layer should be high enough to avoid inconsistencies in the rough model application. At the same time, the grid used for calculations does not strongly influence the numerical results and hence tune of the first element height to perfectly fit the roughness is not always justified. The final analysis on the different gaseous fuels put into evidence the capability of the CFD analysis to determine the energy performance of fuel transportation in gas pipeline. (author)

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Controls on Yardang Morphology: Insights from Field Measurements, Lidar Topographic Analyses, and Numerical Modeling

    Science.gov (United States)

    Pelletier, J. D.; Kapp, P. A.

    2014-12-01

    Yardangs are streamlined bedforms sculpted by the wind and wind-blown sand. They can form as relatively resistant exposed rocks erode more slowly than surrounding exposed rocks, thus causing the more resistant rocks to stand higher in the landscape and deflect the wind and wind-blown sand into adjacent troughs in a positive feedback. How this feedback gives rise to streamlined forms that locally have a consistent size is not well understood theoretically. In this study we combine field measurements in the yardangs of Ocotillo Wells SVRA with analyses of airborne and terrestrial lidar datasets and numerical modeling to quantify and understand the controls on yardang morphology. The classic model for yardang morphology is that they evolve to an ideal 4:1 length-to-width aspect ratio that minimizes aerodynamic drag. We show using computational fluid dynamics (CFD) modeling that this model is incorrect: the 4:1 aspect ratio is the value corresponding to minimum drag for free bodies, i.e. obstacles around which air flows on all sides. Yardangs, in contrast, are embedded in Earth's surface. For such rough streamlined half-bodies, the aspect ratio corresponding to minimum drag is larger than 20:1. As an alternative to the minimum-drag model, we propose that the aspect ratio of yardangs not significantly influenced by structural controls is controlled by the angle of dispersion of the aerodynamic jet created as deflected wind and wind-blown sand exits the troughs between incipient yardang noses. Aerodynamic jets have a universal dispersion angle of 11.8 degrees, thus predicting a yardang aspect ratio of ~5:1. We developed a landscape evolution model that combines the physics of boundary layer flow with aeolian saltation and bedrock erosion to form yardangs with a range of sizes and aspect ratios similar to those observed in nature. Yardangs with aspect ratios both larger and smaller than 5:1 occur in the model since the strike and dip of the resistant rock unit also exerts

  8. Large Eddy Simulations (LES) and Direct Numerical Simulations (DNS) for the computational analyses of high speed reacting flows

    Science.gov (United States)

    Givi, Peyman; Madnia, Cyrus K.; Steinberger, C. J.; Frankel, S. H.

    1992-01-01

    The principal objective is to extend the boundaries within which large eddy simulations (LES) and direct numerical simulations (DNS) can be applied in computational analyses of high speed reacting flows. A summary of work accomplished during the last six months is presented.

  9. 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...

  10. 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.

  11. 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

  12. Late Glacial climate and palaeoenvironment in the Southern Carpathian Mountains inferred by chironomid and pollen analyses

    Science.gov (United States)

    Tóth, M.; Heiri, O.; Magyari, E.; Braun, M.; Buczkó, K.; Bálint, M.; Jakab, G.

    2009-04-01

    The Southern Carpathian Mountains have several glacial lakes with their sediments extending back to the Late Glacial period (ca. 11,500-14,700 calibrated radiocarbon years BP). This area has so far missed quantitative palaeoclimate records that are however much needed in order to obtain a continental-scale picture of ecosystem reorganization in response to rapid climatic changes during the Late Glacial. High-resolution chironomid and pollen analyses can both provide such records. In this study these two methods are applied to the sediment sequence of a small sub-alpine lake, Taul dintre Brazi (Retezat Mts, 1740 m a.s.l., 0.5 ha). The lake is situated on base-poor, granite bedrock, within the Picea abies forest belt. Our aim was (1) to study changes in the chironomid fauna, (2) to obtain summer temperature estimates using a chironomid-mean July air temperature inference model, and finally (3) to compare the chironomid-inferred climate record with a pollen-based quantitative climate record (plant functional type method). Here we provide first results from this multi-proxy study. The Late Glacial and Early Holocene part of this core was analysed at 100-200 yr resolution. During the Oldest Dryas the chironomid fauna was dominated by Pseudodiamesa and Tanytarsini species; the start of the Lateglacial interstadial was marked by the diversification of Tanytarsini (Tanytarsus lugens-type, Tanytarsus pallidicornis-type, Paratanytarsus sp, Micropsectra insignilobus-type) and the disappearance of Pseudodiamesa suggesting a distinct increase in summer temperature. At the same time afforestation by Larix, Pinus cembra, Pinus mugo and Picea abies was signaled by the pollen, stomatal and plant macrofossil records. During the Younger Dryas reversal the chironomid fauna showed increasing abundance of Micropsectra insignilobus-type, a chironomid typical for cool, nutrient poor lakes whereas the pollen, plant macrofossil and stomatal records pointed to a decrease of Picea abies

  13. 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

    The present work applies the shoreline model from part 1 to a real environment. In part 1, a numerical shoreline model which could handle the development of arbitrarily shaped shorelines was applied to consider the development of shoreline undulations on an unstable shoreline exposed to incoming...... 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 describe...

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. The Direct Numerical Simulation of A Turbulent Channel Flow with Analyses of the Database

    Institute of Scientific and Technical Information of China (English)

    ChunxiaoXU; ZhaoshunZHANG

    1996-01-01

    The database of fully developed turbulent channel flow at low Reynolds number is set up through direct numerical simulations.The budget of dissipation-rate of turbulent kinetic energy is calculated and some existing models for the transport equation of the dissipation rate are evaluated.A new model for the turbulent production and viscous destruction terms is given.It makes a considerable improvement in the near-wall behavior,A new flow structure contributing much to high kurtosis levels in transverse velocity fluctuation in viscous sublayer is found.The common characters they possessed are described.

  19. 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.

  20. Detrending phenological time series improves climate-phenology analyses and reveals evidence of plasticity.

    Science.gov (United States)

    Iler, Amy M; Inouye, David W; Schmidt, Niels M; Høye, Toke T

    2017-03-01

    Time series have played a critical role in documenting how phenology responds to climate change. However, regressing phenological responses against climatic predictors involves the risk of finding potentially spurious climate-phenology relationships simply because both variables also change across years. Detrending by year is a way to address this issue. Additionally, detrending isolates interannual variation in phenology and climate, so that detrended climate-phenology relationships can represent statistical evidence of phenotypic plasticity. Using two flowering phenology time series from Colorado, USA and Greenland, we detrend flowering date and two climate predictors known to be important in these ecosystems: temperature and snowmelt date. In Colorado, all climate-phenology relationships persist after detrending. In Greenland, 75% of the temperature-phenology relationships disappear after detrending (three of four species). At both sites, the relationships that persist after detrending suggest that plasticity is a major component of sensitivity of flowering phenology to climate. Finally, simulations that created different strengths of correlations among year, climate, and phenology provide broader support for our two empirical case studies. This study highlights the utility of detrending to determine whether phenology is related to a climate variable in observational data sets. Applying this as a best practice will increase our understanding of phenological responses to climatic variation and change.

  1. 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.

  2. 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.

  3. Measurement of the circumferential mechanical properties of the umbilical vein: experimental and numerical analyses.

    Science.gov (United States)

    Karimi, Alireza; Navidbakhsh, Mahdi; Rezaee, Taraneh; Hassani, Kamran

    2015-01-01

    Coronary artery disease is responsible for almost 30% of all deaths worldwide. The saphenous vein and umbilical vein (UV) are the most common veins using for treatment as a coronary artery bypass graft (CABG). The mechanical properties of UV belonging to its long-term patency for CABG are very important. However, there is a lack of knowledge on the linear elastic and nonlinear hyperelastic mechanical properties of the UV. In this study, three stress definitions (second Piola-Kichhoff stress, engineering stress and true stress) and four strain definitions (Almansi-Hamel strain, Green-St Venant strain, engineering strain and true strain) are used to determine the elastic modulus, maximum stress and strain of eight human UVs under circumferential loading. The nonlinear mechanical behaviour of the UV is computationally investigated using Mooney-Rivlin hyperelastic model. A numerical finite element analysis is also carried out to simulate the constitutive modelling versus its numerical results. The results show that the Almansi-Hamel strain definition overestimates the elastic modulus while Green-St Venant strain definition underestimates the elastic modulus at different stress definitions. The true stress-true strain definition, which gives more accurate measurements of the tissue's response using the instantaneous values, reveals the Young's modulus and maximum stress of 2.18 and 6.01 MPa, respectively. The Mooney-Rivlin material model is well represented by the nonlinear mechanical behaviour of the UV. The findings of this study could have implications not only for understanding the extension and rupture mechanism of UV but also for interventions and surgeries, including balloon angioplasty, bypass and stenting.

  4. 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.

  5. 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)

  6. 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

  7. 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

  8. 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.

  9. 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).

  10. 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.

  11. 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.

  12. 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.

  13. Impacts of the 2011 East Japan tsunami in the Papua region, Indonesia: field observation data and numerical analyses

    Science.gov (United States)

    Diposaptono, Subandono; Muhari, Abdul; Imamura, Fumihiko; Koshimura, Shunichi; Yanagisawa, Hideaki

    2013-09-01

    This paper presents post-tsunami survey results describing the impacts of the 2011 East Japan tsunami in Yos Sudarso Bay, Papua, Indonesia. Although the far-field tsunami had a height of 0.8 m measured at a tide gauge inside the small U-shaped bay, it severely damaged four villages scattered along the bay. Detailed numerical analysis was carried out to explain the damages. We used a well-verified source model in the near- and far-field cases to model the propagation of the tsunami southward in the Pacific until reaching Papua Island, Indonesia. The numerical analyses demonstrate two causes of damage in the bay: the maximum tsunami velocity (3.5 m s-1) floated the houses in the villages of Tobati and Enggros and caused them to collapse, and water trapped by the hook-shaped peninsula amplified the tsunami height at the Holtekamp and Hanurata.

  14. Numerical simulation of greening effects for idealised roofs with regional climate forcing

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Guenter [Hannover Univ. (Germany). Inst. fuer Meteorologie und Klimatologie

    2012-04-15

    A numerical model was used to simulate temperature distribution in and above an extensive green roof with a long term forcing adopted from a regional climate model. Time variations of temperature for different time scales ranging from days to decades have been calculated. The results are in good agreement with selected field experiments and generally reinforce the understanding prevailing in literature regarding temperature differences of green roofs compared to a concrete roof. Green roofs result in a significant reduction of daytime human heat load and an improvement of thermal comfort conditions, while during night-time a concrete roof favours low temperatures and a low number of minimum temperatures above 20 C (tropical nights). A future shift in seasonal precipitation would necessitate irrigation in the summer months to ensure the vitality of roof vegetation. An estimation of the amount of additional watering and the increased number of watering days per year is given. (orig.)

  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

    2013-10-01

    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.

  16. 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

  17. 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.

  18. 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.

  19. Spatio-temporal analyses of impacts of multiple climatic hazards in a savannah ecosystem of Ghana

    Directory of Open Access Journals (Sweden)

    Gerald A.B. Yiran, PhD

    2016-01-01

    Full Text Available Ghana’s savannah ecosystem has been subjected to a number of climatic hazards of varying severity. This paper presents a spatial, time-series analysis of the impacts of multiple hazards on the ecosystem and human livelihoods over the period 1983–2012, using the Upper East Region of Ghana as a case study. Our aim is to understand the nature of hazards (their frequency, magnitude and duration and how they cumulatively affect humans. Primary data were collected using questionnaires, focus group discussions, in-depth interviews and personal observations. Secondary data were collected from documents and reports. Calculations of the standard precipitation index (SPI and crop failure index used rainfall data from 4 weather stations (Manga, Binduri, Vea and Navrongo and crop yield data of 5 major crops (maize, sorghum, millet, rice and groundnuts respectively. Temperature and windstorms were analysed from the observed weather data. We found that temperatures were consistently high and increasing. From the SPI, drought frequency varied spatially from 9 at Binduri to 13 occurrences at Vea; dry spells occurred at least twice every year and floods occurred about 6 times on average, with slight spatial variations, during 1988–2012, a period with consistent data from all stations. Impacts from each hazard varied spatio-temporally. Within the study period, more 70% of years recorded severe crop losses with greater impacts when droughts and floods occur in the same year, especially in low lying areas. The effects of crop losses were higher in districts with no/little irrigation (Talensi, Nabdam, Garu-Tempane, Kassena-Nankana East. Frequency and severity of diseases and sicknesses such as cerebrospinal meningitis, heat rashes, headaches and malaria related to both dry and wet conditions have increased steadily over time. Other impacts recorded with spatio-temporal variations included destruction to housing, displacement, injury and death of people. These

  20. 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

  1. 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.

  2. Alluvial fan response to climatic change: Insights from numerical modeling (Invited)

    Science.gov (United States)

    Pelletier, J. D.

    2009-12-01

    Alluvial fans in the western U.S. exhibit a regionally correlative sequence of Plio-Quaternary deposits. Cosmogenic and U-series dating has greatly improved the age control on these deposits and their associated terraces and generally strengthened the case for aggradation during humid-to-arid transitions. Still, the linkages between climate change, upland basin response, and alluvial fan response are not well constrained. Fans may fill and cut as a result of autogenetic processes/internal adjustments, changes in regional temperature (which controls snowmelt-induced flooding), changes in the frequency-size distribution of rainfall events, and/or changes in upslope vegetation. Here I describe the results of a numerical modeling study designed to better constrain the relationships between different end-member forcing mechanisms and the geologic record of alluvial fan deposits and terraces. The model solves the evolution of the fan topography using Exner's equation (conservation of mass) coupled with a nonlinear, threshold-controlled transport relation for sand and gravel. Bank retreat is modeled using an advection equation with a rate proportional to bank shear stress. I begin by considering the building of a fan under conditions of constant water and sediment supply. This simple system exhibits all of the complexity of fans developed under experimental conditions, and it provides insights into the mechanisms that control avulsions and it provides a baseline estimate for the within-fan relief that can result from autogenetic processes. Relationships between the magnitude and period of variations in the sediment-to-water ratio and the geomorphic response of fans are then discussed. I also consider the response of a coupled drainage basin-fan system to changes in climate, including the hydrologic and vegetation response of upland hillslopes. Fans can aggrade or incise in response to the same climatic event depending on the relief of the upstream drainage basin, which

  3. 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

  4. A numerical investigation on exergy analyses of a pyroelectric tryglycine sulfate (TGS)-based solar energy harvesting system

    Science.gov (United States)

    Sharma, Manish; Vaish, Rahul; Singh Chauhan, Vishal

    2016-02-01

    This study is based on a numerical demonstration of energy and exergy analyses of a solar energy harvesting system based on the pyroelectric effect. The performance of a tryglycine sulfate (TGS) single crystal was investigated mathematically in the present study. The power output was optimized for different load resistances and load capacitances. The maximum power output was obtained as 0.95 μW across a load resistance of 40 MΩ and a 4.7 μF load capacitor. Further exergy analysis was performed for a pyroelectric energy harvesting system. Maximum values for electrical and thermal exergies obtained are 0.12 μW and 12 mW, respectively. Furthermore the maximum obtained electrical and thermal exergy efficiencies are 0.000 037% and 3.6%, respectively. The average thermal exergy efficiency is 2.15% for a cycle frequency of 0.014 Hz.

  5. 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.

  6. A graphical user interface for numerical modeling of acclimation responses of vegetation to climate change

    Science.gov (United States)

    Le, Phong V. V.; Kumar, Praveen; Drewry, Darren T.; Quijano, Juan C.

    2012-12-01

    Ecophysiological models that vertically resolve vegetation canopy states are becoming a powerful tool for studying the exchange of mass, energy, and momentum between the land surface and the atmosphere. A mechanistic multilayer canopy-soil-root system model (MLCan) developed by Drewry et al. (2010a) has been used to capture the emergent vegetation responses to elevated atmospheric CO2 for both C3 and C4 plants under various climate conditions. However, processing input data and setting up such a model can be time-consuming and error-prone. In this paper, a graphical user interface that has been developed for MLCan is presented. The design of this interface aims to provide visualization capabilities and interactive support for processing input meteorological forcing data and vegetation parameter values to facilitate the use of this model. In addition, the interface also provides graphical tools for analyzing the forcing data and simulated numerical results. The model and its interface are both written in the MATLAB programming language. Finally, an application of this model package for capturing the ecohydrological responses of three bioenergy crops (maize, miscanthus, and switchgrass) to local environmental drivers at two different sites in the Midwestern United States is presented.

  7. 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

  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. 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.)

  13. 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

  14. 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.

  15. 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.

  16. Long-Term Sun Climate Connections, Revealed by the Analyses of Historical and Other Proxy Records

    Science.gov (United States)

    Pang, K. D.; Yau, K.

    2004-12-01

    The Sun, once considered constant, actually goes through 11-year, decadal, centennial, and even longer cycles. Our analysis of historical sunspot and aurora records, carbon-14 and beryllium-10 abundances from long-lived trees and deep polar ice cores, respectively, shows that it has gone through nine long cycles in the past 1800 years. Although these changes amounted to China). Total solar irradiances, reconstructed from historical sunspot records, were 0.25% lower then. This correlates nicely with an estimated 0.5-degree drop in Northern Hemisphere summer surface temperatures during the Little Ice Age [Lean, GRL 22, 3195, 1995]. We have also analyzed Chinese historical weather records for comparison. Reports of unseasonable cold are classified by the degree of severity: (1) Late (April-June) or early (July-September) killing frosts; (2) Bitter cold/heavy snowfall; and (3) Heavy sustained snowfall, bitter cold with frozen wells, rivers and icebound seas. The latter cases were often widespread and multi-year. All categories occurred most frequently during the coldest part of the Little Ice Age. The Category 3 episodes were in 1652-54, 1656, 1664, 1670-72, 1676-77, 1683, 1688-91, 1716, and 1718-19. For example the Yangtze River and its lakes froze up to 3-4 times in 1650-1700. The coldest period thus coincides with the Maunder Minimum, and is consistent with general circulation model hindcast winter conditions for China [Shindell, Science, 294, 2149, 2001]. There was only one Category 3 episode between the Maunder and Dalton Minima--in 1761 (due to a large volcanic eruption); and two in the Dalton Minimum (1795-1825)--in 1796 and 1814-17. The Sun has gradually brightened since the Dalton Minimum. But the climate of China remained cold through the 19th century, as in the rest of the world, probably due to increased volcanic aerosol loading of the atmosphere [Sato, JGR 98, 22987, 1993]. The climate of China seems to have been warm during the Late 14th-Century Maximum

  17. 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.

  18. Direct numerical simulation and stability analyses of three-dimensional swirling jets and wakes exhibiting vortex breakdown

    Science.gov (United States)

    Ruith, Michael Rudolf

    Vortex breakdown of nominally axisymmetric, swirling incompressible jets and wakes issuing into a semi-infinite domain is studied by means of direct numerical simulations, as well as local and global linear stability analyses. From the point of view of specifying conditions at the open boundaries, this class of flows is particularly challenging due to its ability to support traveling waves. Several boundary conditions, ranging from free-slip and various homogeneous Neumann conditions to radiation conditions, are implemented in a staggered grid, finite difference algorithm that solves the unsteady Navier-Stokes equations in cylindrical coordinates by means of a fractional step method. Their advantages and shortcomings are evaluated in detail, and the question of the proper implementation of intermediate step boundary conditions is addressed. The data obtained from a large variety of test simulations points to the radiation condition as the most suitable lateral and outflow boundary condition for both high and low entrainment jets and wakes. A two-parameterc low entrainment velocity profile for which the steady, axisymmetric breakdown is well studied is selected for further investigation. Hence, issues regarding the role of three-dimensionality and unsteadiness with respect to the existence, mode selection, and internal structure of vortex breakdown can be addressed in terms of the two governing parameters and the Reynolds number. Low Reynolds numbers are found to yield flow fields lacking breakdown bubbles or helical breakdown modes even for high swirl. In contrast, highly swirling flows at large Reynolds numbers exhibit bubble, helical or double helical breakdown modes, where the axisymmetric mode is promoted by a jet-like axial velocity profile, while a wake-like profile renders the flow helically unstable and ultimately yields non-axisymmetric breakdown modes. It is shown that a transition from super- to subcritical flow, accurately predicts the parameter

  19. SWIFT: Semi-empirical and numerically efficient stratospheric ozone chemistry for global climate models

    OpenAIRE

    Kreyling, Daniel; Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2015-01-01

    The SWIFT model is a fast yet accurate chemistry scheme for calculating the chemistry of stratospheric ozone. It is mainly intended for use in Global Climate Models (GCMs), Chemistry Climate Models (CCMs) and Earth System Models (ESMs). For computing time reasons these models often do not employ full stratospheric chem- istry modules, but use prescribed ozone instead. This can lead to insufficient representation between stratosphere and troposphere. The SWIFT stratospheric ozone chem...

  20. Numerical Simulation of Regional Climate Change under IPCC A2 Scenario in China

    Institute of Scientific and Technical Information of China (English)

    TANG Jianping; CHEN Xing; ZHAO Ming; SU Bingkai

    2009-01-01

    Regional climate change in China under the IPCC A2 Scenario, was simulated for continuous 10-yr period by the MM5V3, using the output of an IPCC A2 run from CISRO Mark 3 climate system model as lateral and surface boundary conditions. The regional climate change of surface air temperature, precipitation, and circulation were analyzed. The results showed that (1) the distribution of mean circulation, surface air temperature, and precipitation was reproduced by the MM5V3. The regional climate model was capable to improve the regional climate simulation driven by GCM. (2) The climate change simulation under the IPCC A2 Scenario indicated that the surface air temperature in China would increase in the future, with a stronger trend in winter and the increasing magnitude from the south to the north. The precipitation distribution would appear a distinct change as well. Annual mean precipitation would remarkably increase in Northeast China, Yangtze and Huaihe River Valley, and the south area of the valley. Meanwhile, rainfall would show a decreasing trend in partial areas of North China, and many regions of Southwest and Northwest China.

  1. 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.

  2. 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

  3. 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.

  4. Numerical modeling study into the climatic impact of deforestation associated with the fall of Mayan Empire

    Science.gov (United States)

    Kongoli, C.; Nair, U. S.; Welch, R. M.; Sever, T. L.; Irwin, D.; Pielke, R. A.

    2002-05-01

    The collapse the Mayan Empire, which flourished from 250 to 900 AD in the Southern Mexico and Central American regions, is one of the greatest demographic disasters in the human history. Early studies of Mayan civilization found cessation in dating and inscription of monuments in the ninth century. Later studies suggest a two-thirds decline in Mayan population numbering millions between 830 and 900 AD. The reason for this population decline and the subsequent collapse of Mayan Empire in ninth century is not known. The mass exodus of population has been ruled out since the population in the surrounding regions remained stable during this time period. Other suggested reasons for this population decline include conflict, disease, warfare, climate change. However, studies of historical pollen data indicate increased rates of deforestation starting in the fifth century with most of the trees in the region being cut down by the ninth century. Lake core sediments document a major drought around 800 AD that was one of the most intense drought in an 8000 year history. A recent study on climatic reconstruction from pollen records also indicate that climate became drier following the collapse of the Mayan Empire, and suggest that this may be due to the cutting down of trees. In the present study, the effect of forest clearing on the regional climate in the Mayan region is examined using the Colorado State University Regional Atmospheric Modeling System (CSU RAMS). The RAMS is being used to simulate the rainfall over the Mayan region for conditions where the surface is assumed to be completely forested and deforested. Simulations are being done for two months, both in the wet and dry season. Comparison of RAMS simulated rainfall between the completely forested and deforested scenarios are expected to provide bounds on regional climate change brought about by deforestation. Further details will be presented at the conference.

  5. Tropical cyclones in a T159 resolution global climate model: comparison with observations and re-analyses

    Science.gov (United States)

    Bengtsson, L.; Hodges, K. I.; Esch, M.

    2007-08-01

    Tropical cyclones have been investigated in a T159 version of the MPI ECHAM5 climate model using a novel technique to diagnose the evolution of the three-dimensional vorticity structure of tropical cyclones, including their full life cycle from weak initial vortices to their possible extra-tropical transition. Results have been compared with re-analyses [the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-yr Re-analysis (ERA40) and Japanese 25 yr re-analysis (JRA25)] and observed tropical storms during the period 1978-1999 for the Northern Hemisphere. There is no indication of any trend in the number or intensity of tropical storms during this period in ECHAM5 or in re-analyses but there are distinct inter-annual variations. The storms simulated by ECHAM5 are realistic both in space and time, but the model and even more so the re-analyses, underestimate the intensities of the most intense storms (in terms of their maximum wind speeds). There is an indication of a response to El Niño-Southern Oscillation (ENSO) with a smaller number of Atlantic storms during El Niño in agreement with previous studies. The global divergence circulation responds to El Niño by setting up a large-scale convergence flow, with the centre over the central Pacific with enhanced subsidence over the tropical Atlantic. At the same time there is an increase in the vertical wind shear in the region of the tropical Atlantic where tropical storms normally develop. There is a good correspondence between the model and ERA40 except that the divergence circulation is somewhat stronger in the model. The model underestimates storms in the Atlantic but tends to overestimate them in the Western Pacific and in the North Indian Ocean. It is suggested that the overestimation of storms in the Pacific by the model is related to an overly strong response to the tropical Pacific sea surface temperature (SST) anomalies. The overestimation in the North Indian Ocean is likely to be due to an over

  6. 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.

  7. 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.

  8. 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

    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...... 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...

  9. 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

  10. 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

    Molecular epidemiological studies of the enteric pathogen Campylobacter jejuni have suggested that not all animal isolates are equally pathogenic to humans. We examined the use of numerical analysis of whole-genomotype data as a potential tool for evaluating C. jejuni virulence potential. Whole-g...

  11. Numerical modelling and analysing of conjugate radiation- convective heat transfer of fin-tube radiator of spacecraft

    Science.gov (United States)

    Delcov, A.; Hodenkov, A.; Zhuikov, D.

    2015-10-01

    This paper covered the problem of assessing the effectiveness of the section of the fin-tube radiator of space thermal control system. The task of calculating the conjugate radiation-convective heat transfer is presented. The results of numerical simulation are described.

  12. 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 ...

  13. 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.

  14. 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.

  15. 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.

  16. 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

    at the post-breakage stage - is investigated. From the results of the analyses it is observed that the residual load-bearing capacity, i.e. the load-bearing capacity after glass fracture, increases with an increasing shear modulus of the SG-interlayer. Furthermore, the load-displacement response from...

  17. A numerical model to simulate physical states of snowpack for climate studies

    Science.gov (United States)

    Niwano, M.; Aoki, T.; Kuchiki, K.; Hosaka, M.; Kodama, Y.

    2011-12-01

    In recent years, several physically based snow albedo models for general circulation models (GCMs) have been developed to improve the accuracy of climate simulations. Since these snow albedo models generally require snow grain size or specific surface area of snow as an input parameter, internal physical states of snowpack should also be calculated accurately in GCMs. For this reason, we developed a multilayered physical snowpack model named Snow Metamorphism and Albedo Process (SMAP) model. SMAP model takes energy balance, mass balance, snow settlement, phase changes, water percolation, and snow metamorphism into account. We validated SMAP model using meteorological and snow impurities (black carbon and dust) data measured during 2007-2009 winters (November to April) at Sapporo, Japan. The root mean square error (RMSE) values of snow depth were 0.064 m for 2007-2008 winter and 0.075 m for 2008-2009 winter. The RMSE values of shortwave albedo were 0.051 for 2007-2008 winter and 0.084 for 2008-2009. Although the RMSE value of shortwave albedo during 2008-2009 winter was somewhat large, it was attributed to an error that SMAP model could not simulate rapid complete melting. In fact, we obtained the RMSE value of 0.048 from 1 January to 15 March, 2009 when simulated snowpack continuously survived whole time. These results confirm that SMAP model can be used for climate simulations as well as studies on snow physical processes. Using SMAP model, we investigated the effects of snow impurities on snowmelt at Sapporo by means of "pure snow experiment". We found that snowpack durations at Sapporo were shortened by 19 days during 2007-2008 winter and 16 days during 2008-2009 winter by the forcing of snow impurities.

  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. Theoretical analyses and numerical simulations of the torsional mode for two acoustic viscometers with preliminary experimental tests.

    Science.gov (United States)

    Ai, Yuhui; Lange, Rebecca A

    2008-03-01

    A rigorous analysis of the torsional modes in both a cylindrical wave guide and the associated static viscous fluid field has been conducted from the solid and the fluid wave equations and the coupled boundary conditions. As a result, two acoustic viscometer models, along with four independent equations connecting the density and the viscosity of the fluid with the attenuation and the phase velocity of the torsional wave in the wave guide, have been developed. The analysis shows that the product of the viscosity and the density of the fluid can be measured from the end reflection coefficient of the torsional wave in the wave guide and that both the viscosity and the density can be determined simultaneously from either the phase velocity or the attenuation of the torsional wave in a single cylindrical wave guide. For the simultaneous measurements of the viscosity and the density, the independent equations have to be solved numerically, for example, using Matlab (The MathWorks, Natick, MA), given either the attenuation or the phase velocity in the wave guide that is surrounded by the fluid. To demonstrate the technical feasibility, numerical simulations have been conducted to discern viscosity, phase velocity, and density, all versus attenuation, at different frequencies, and with variable dimension of a molybdenum rod, so that both the advantages and the disadvantages of the simultaneous measurements can be explored. In the end, to test the two models, preliminary experiments on two viscous standards were conducted at 23 degrees C, and good agreements have been achieved between the viscosities measured from both models and for both standards.

  2. Application of the flow dimension concept for numerical drawdown data analyses in mixed-flow karst systems

    Science.gov (United States)

    Giese, M.; Reimann, T.; Liedl, R.; Maréchal, J.-C.; Sauter, M.

    2017-01-01

    A numerical discrete conduit-continuum model is employed to investigate large-scale groundwater abstraction in karst aquifers. The application of large-scale experiments is one approach to deal with the scale problem in hydraulic parameter assessment, caused by significant contrasts of hydraulic parameters in a karst aquifer. Here, conduit drawdown is evaluated by diagnostic plots and by considering the apparent flow dimension. These tools are frequently used for the interpretation of hydraulic borehole tests by analytical solutions. In contrast to existing analytical solutions, a numerical groundwater model allows the incorporation of the effect of complex parameter distributions. The objective is to demonstrate the application of diagnostic plots and flow dimension analysis for a systematic analysis of the effect of different boundary conditions as well as sink/source terms for idealized two-dimensional mixed karst aquifer systems, which ultimately extends existing analytical solutions and, therefore, contributes to the interpretation of measured field data. The analysis is focused on the apparent flow dimension and shows the extension of the cross-sectional flow area for selected models. The results are used to evaluate the large-scale pumping test of the karstified Cent Fonts catchment (Languedoc, France). The inverse calibration of two realistic, but still simplified, catchment models reveals that the apparent flow dimension supplies useful information about the general flow pattern during the Cent Fonts pumping test. The flow dimension after the end of the storage period can be explained by a large contribution of exchange flow resulting in a strong influence of radial flow on regional, i.e., kilometer scale.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. The future thermal regime of numerical simulating permafrost on Qinghai-Xizang (Tibet) Plateau, China, under climate warming

    Institute of Scientific and Technical Information of China (English)

    李述训; 程国栋; 郭东信

    1996-01-01

    Numerical simulation indicates that the future thermal regime of permafrost on Qinghai-Xizang Plateau will change as the air temperature continuously rises at 0.04℃/a. The calculated results show that when Ts are 0, -0.5, -1.5, -2.5, -3.5 and - 4.5℃ under equilibium between climate and permafrost thermal regime, the mean annual temperatures at the depth of 14 m correspondingly equal to -0.11, -0.59, -1.52, -2.45, -3.21 and -4.32℃, and the permafrost thicknesses respectively equal to 16.8, 29.0, 54.1, 79.4, 112.1 and 131.0m. 50 years later, the temperatures at the depth of 14m will rises to 0.0, 0.0, -0.36, -1.23, -2.16, -3.06℃ under the given condition. When TS is lower than -1.1℃, the permafrost will respectively change from initial 2.0, 1.8, 1.6, 1.4m to 2.2, 2.0, 1.8, 1.6m for TS=-1.5, -2.5. - 3.5 and -4.5℃. If TS is higher than - 1.1℃, the frozen ground will change from the attachment type of frozen ground into the detachment type of frozen ground. Therefore, if future air temperature rises a

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

    DEFF Research Database (Denmark)

    Guillevic, Myriam

    'Environnement, France). At the Centre for Ice and Climate (CIC, Denmark) we contribute to the development of a protocol for absolute referencing of methane gas isotopes, and making full air standard with known concentration and isotopic composition of methane. Then, air (δ15N) and water stable isotope measurements from......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...

  13. Examining the response of needle carbohydrates from Siberian larch trees to climate using compound-specific δ(13) C and concentration analyses.

    Science.gov (United States)

    Rinne, K T; Saurer, M; Kirdyanov, A V; Bryukhanova, M V; Prokushkin, A S; Churakova Sidorova, O V; Siegwolf, R T W

    2015-11-01

    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 (δ(13) C) 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 δ(13) C values as a response to climate were detected. The δ(13) C 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.

  14. 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

    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......%) 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...

  15. Study on convective mixing for thermal striping phenomena. Experimental analyses on mixing process in parallel triple-jet and comparisons between numerical methods

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, N.; Kamide, H.; Nishimura, M. [Japan Nuclear Cycle Development Institute, O-arai Engineering Center, Ibaraki (Japan)

    2001-07-01

    A quantitative evaluation on thermal striping, in which temperature fluctuation due to convective mixing imposes thermal fatigue on structural components, is of importance for reactor safety. As for convective mixing in fluid, a water experiment was performed on vertical, parallel triple-jet: a cold jet at the center and hot jets in both side. Mixing behavior between the triple jets and frequency characteristics of temperature fluctuation were obtained by temperature measurement. Three kinds of numerical analyses based on the finite difference method for the experiment were carried out. Two types of turbulence models were used in the calculations, namely k-i two equation turbulence model (k-i Model) and low Reynolds number turbulence stress and heat flux equation model (LRSFM). Furthermore, a direct numerical simulation (DNS) was performed. The DNS could simulate the time-averaged temperature field in the experiment. The results obtained from the k-i Model and the LRSFM reached uniform temperature more downstream than in the experiment and overestimated the temperature fluctuation intensities in the mixing region. As for the prominent frequency in temperature fluctuation due to oscillation of the jets, the frequency obtained by the LRSFM was in good agreement with that in the experiment. The profile of power spectrum density of temperature fluctuations calculated by the DNS was close to the experimental results. The DNS is applicable to the convective mixing of multiple jets. (author)

  16. The record of Miocene climatic events in AND-2A drill core (Antarctica): Insights from provenance analyses of basement clasts

    Science.gov (United States)

    Sandroni, Sonia; Talarico, Franco M.

    2011-01-01

    This paper includes the results of a detailed quantitative provenance investigation on gravel-size clasts occurring within the late Early to Late Miocene sedimentary glacimarine section recovered for the first time by the AND-2A core in the SW sector of the Ross Sea (southern McMurdo Sound, Antarctica). This period of time is of crucial interest, as it includes two of the major Cenozoic events in the global climatic evolution: the mid-Miocene climatic optimum and the middle Miocene climate transition. Petrographical and mineral chemistry data on basement clasts allow to individuate two different diagnostic clast assemblages, which clearly suggest two specific sectors of southern Victoria Land as the most likely sources: the Mulock-Skelton glacier and the Koettlitz-Blue glacier regions. Distribution patterns reveal high fluctuations of the detritus source areas throughout the investigated core interval, variations which can be interpreted as the direct result of an evolving McMurdo Sound paleogeography during the late Early to Late Miocene. Consistently with sedimentological studies, gravel-fraction clast distribution patterns clearly testify that the Antarctic ice sheet experienced a dramatic contraction at ca. 17.35 ± 0.14 Ma (likely correlated to the onset of the climatic optimum), and in a gravel-fraction clasts show that the variations of paleoenvironmental drivers characterising this period were able to exert deep transformation of the Antarctic ice sheet and reveal the methodology to be a powerful tool for the reconstruction of paleo-glacial-flow direction and paleogeographic scenarios.

  17. 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.

  18. Regionwide Geodynamic Analyses of the Cenozoic Carbonate Burial in Sri Lanka Related to Climate and Atmospheric CO2

    Directory of Open Access Journals (Sweden)

    Amila Sandaruwan Ratnayake

    2016-12-01

    Full Text Available Asian tectonism and exhumation are critical components to develop modern icehouse climate. In this study, stratigraphic sections of eight wells in the Mannar and Cauvery basins were considered. The author demonstrated that this local system records a wealth of information to understated regional and global paleoclimatic trends over the Cenozoic era. The lithostratigraphic framework has been generally characterized by deposition of carbonate-rich sediments since the Middle Cenozoic. Geological provenance of carbonate sediments had probably related to local sources from Sri Lankan and Indian land masses. The main controlling factor of carbonate burial is rather questionable. However, this carbonate burial has indicated the possible link to the Middle to Late Cenozoic global climatic transition. This major climatic shift was characterized by long-term reduction of atmospheric carbon dioxide concentration over the Cenozoic era. Consequently, this geological trend (carbonate burial has a straightforward teleconnection to the global cooling towards the glaciated earth followed by the development of polar ice sheets that persist today.

  19. 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.

  20. Portfolio effects, climate change, and the persistence of small populations: analyses on the rare plant Saussurea weberi.

    Science.gov (United States)

    Abbott, Ronald E; Doak, Daniel F; Peterson, Megan L

    2017-04-01

    The mechanisms that stabilize small populations in the face of environmental variation are crucial to their long-term persistence. Building from diversity-stability concepts in community ecology, within-population diversity is gaining attention as an important component of population stability. Genetic and microhabitat variation within populations can generate diverse responses to common environmental fluctuations, dampening temporal variability across the population as a whole through portfolio effects. Yet, the potential for portfolio effects to operate at small scales within populations or to change with systematic environmental shifts, such as climate change, remain largely unexplored. We tracked the abundance of a rare alpine perennial plant, Saussurea weberi, in 49 1-m(2) plots within a single population over 20 yr. We estimated among-plot correlations in log annual growth rate to test for population-level synchrony and quantify portfolio effects across the 20-yr study period and also in 5-yr subsets based on June temperature quartiles. Asynchrony among plots, due to different plot-level responses to June temperature, reduced overall fluctuations in abundance and the probability of decline in population models, even when accounting for the effects of density dependence on dynamics. However, plots became more synchronous and portfolio effects decreased during the warmest years of the study, suggesting that future climate warming may erode stabilizing mechanisms in populations of this rare plant.

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

    Science.gov (United States)

    Lo Frano, R.; Moscardini, M.; Aquaro, D.

    2014-11-01

    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.

  2. 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.

  3. 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.

  4. Numerical Analyses of the Non-Newtonian Flow Performance and Thermal Effect on a Bearing Coated with a High Tin Content

    Directory of Open Access Journals (Sweden)

    K. Mehala

    2016-12-01

    Full Text Available The hydrodynamic bearings are stressed by severe workings conditions, such as speed, load, and the oil will be increasingly solicit by pressure and shear. The Newtonian behavior is far from being awarded in this case, the most loaded bearings operating at very high speeds; the shear rate of the oil is of higher order. A numerical analysis of the behavior of non-Newtonian fluid for plain cylindrical journal bearing finite dimension coated with antifriction material with a high tin content, for to facilitate the accommodation of the surfaces and save the silk of the shaft in the case of a contact. this analyses is implemented using the code-ANSYS CFX, by solving the energy equation with the finite difference method, considering that laminar regime and the fluid is non Newtonian by using the power law Ostwald model, the coefficient n is equal to 1.25 and for different model such as Bingham, cross and Hereshek-Bulkley model. This study aims to better predict the non-Newtonian behavior of the oil film in bearings operating under more severe conditions. The purpose conducted during this study is to predict the effect of non-Newtonian behavior of the film; the journal bearing operating under severe conditions, the speed of rotation varies from 1000 to 9000 rpm and the bearing working under radial load 2 to 10 kN. Temperature and the pressure within the fluid film assumed non-Newtonian are high, with a coefficient n greater than 1 that is to say for viscoelastic fluids.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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)

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Climate-dependent sediment production: numerical modeling and field observations of variable grain size distributions from heterogeneous hillslope weathering of fractured basalt flows, Kohala Peninsula, Hawaii

    Science.gov (United States)

    Murphy, B. P.; Johnson, J. P.

    2012-12-01

    We present a numerical model for hillslope sediment production that includes climate-dependent chemical weathering rates and bedrock fracture spacings, and predicts how grain size distributions vary with climate and hillslope erosion rate. Understanding sediment preparation, or the in situ reduction of fractured bedrock to coarse sediment by heterogeneous weathering on hillslopes, is critical to understanding the evolution of mountainous landscapes, as sediment supply rates and size distributions can strongly influence river incision rates. The majority of soil production models assume a homogenous substrate and uniform weathering front, and therefore do not track the size of rock fragments and corestones, which become the sediment supplied to channels by hillslope erosion. Our model is inspired by the Kohala Peninsula on the big island of Hawaii, which has a gradient of mean annual precipitation (MAP) spanning over an order of magnitude that has been shown to influence the weathering rates of the basalt. Previous geochemical studies have constrained climate-dependent weathering rates for local soil production. Using these inputs, we developed a kinetics-based numerical model for the chemical weathering of initially fractured basalt into soil and coarse sediment over 150ky. Following first-order reaction kinetics, chemical weathering in the model decreases exponentially with both depth below the surface and time. The model starts with a column of repeating basalt flows (typically 1 m thick), each with fracture spacing distributions consistent with thermal-mechanical cooling characteristics. Each individual fracture-bound block is assumed to weather from the surface inwards, similar in form to a weathering rind. Since the model is constructed of discrete blocks, larger blocks remain as unweathered corestones (the "sediment"), surrounded by weathered material. In addition to a MAP-dependent initial surface weathering rate and rate constant, climate is also reflected

  17. 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

  18. Numerical modelling of climate change impacts on freshwater lenses on the North Sea Island of Borkum using hydrological and geophysical methods

    Directory of Open Access Journals (Sweden)

    H. Sulzbacher

    2012-10-01

    Full Text Available A numerical, density dependent groundwater model is set up for the North Sea Island of Borkum to estimate climate change impacts on coastal aquifers and especially the situation of barrier islands in the Wadden Sea. The database includes information from boreholes, a seismic survey, a helicopter-borne electromagnetic (HEM survey, monitoring of the freshwater-saltwater boundary by vertical electrode chains in two boreholes, measurements of groundwater table, pumping and slug tests, as well as water samples. Based on a statistical analysis of borehole columns, seismic sections and HEM, a hydrogeological model is set up. The groundwater model is developed using the finite-element programme FEFLOW. The density dependent groundwater model is calibrated on the basis of hydraulic, hydrological and geophysical data, in particular spatial HEM and local monitoring data. Verification runs with the calibrated model show good agreement between measured and computed hydraulic heads. A good agreement is also obtained between measured and computed density or total dissolved solids data for both the entire freshwater lens on a large scale and in the area of the well fields on a small scale.

    For simulating future changes in this coastal groundwater system until the end of the current century, we use the climate scenario A2, specified by the Intergovernmental Panel on Climate Change and, in particular, the data for the German North Sea coast. Simulation runs show proceeding salinisation with time beneath the well fields of the two waterworks Waterdelle and Ostland.

    The modelling study shows that the spreading of well fields is an appropriate protection measure against excessive salinisation of the water supply until the end of the current century.

  19. Hydrogeological flux scenarios at Forsmark. Generic numerical flow simulations and compilation of climatic information for use in the safety analysis SFR1 SAR-08

    Energy Technology Data Exchange (ETDEWEB)

    Vidstrand, Patrik (Bergab, Goeteborg (SE)); Naeslund, Jens-Ove (Swedish Nuclear Fuel and Waste Management Co., Stockholm (SE)); Hartikainen, Juha (Helsinki Univ. of Technology, Helsinki (FI)); Svensson, Urban (CFE AB, Karlskrona (SE))

    2007-11-15

    In the earlier modelling for SFR-SAFE it was concluded that the groundwater flow would increase with time along with the shoreline displacement. Even though the numerical results are different the same conclusion is drawn after this study. General conclusions from the present study are that: The upper boundary conditions have a significant impact on the groundwater flow in the geosphere. The characteristic of the surface in regards of being a recharge or discharge area affects the results. In general, a discharge area will experience an increase in groundwater flow under changed conditions. The presence of caging fracture zones affects the results, and, for the tested un-frozen SFR situation, the resulting effect is an increase in groundwater flow. Specific conclusions regarding the relative change of groundwater flow due to different surface conditions are that: The permafrost scenarios, along with the development from sporadic permafrost to continuous permafrost, yield increased groundwater flows in unfrozen parts of the domain. The increase is one order of magnitude or less. In the permafrost, the flow is negligible. The ice sheet scenarios yield situations with significantly increased groundwater flow. The results indicate an increase by two to three orders of magnitude. These increased values, however, apply only for short duration intervals. It is possible that such intervals may be only a couple of years. In the selected climate Base variant, repeating the conditions for the last glacial cycle, permafrost conditions occur after 8,000 years. In the climate variant affected by increased greenhouse warming, permafrost conditions do not occur until after more than 50,000 years. In the chosen climate variants, ice sheets reach the Forsmark area and cause significantly increased groundwater flow, after approx60,000 years or more

  20. 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.

  1. The uncertainty of UTCI due to uncertainties in the determination of radiation fluxes derived from numerical weather prediction and regional climate model simulations.

    Science.gov (United States)

    Schreier, Stefan F; Suomi, Irene; Bröde, Peter; Formayer, Herbert; Rieder, Harald E; Nadeem, Imram; Jendritzky, Gerd; Batchvarova, Ekaterina; Weihs, Philipp

    2013-03-01

    In this study we examine the determination accuracy of both the mean radiant temperature (Tmrt) and the Universal Thermal Climate Index (UTCI) within the scope of numerical weather prediction (NWP), and global (GCM) and regional (RCM) climate model simulations. First, Tmrt is determined and the so-called UTCI-Fiala model is then used for the calculation of UTCI. Taking into account the uncertainties of NWP model (among others the HIgh Resolution Limited Area Model HIRLAM) output (temperature, downwelling short-wave and long-wave radiation) stated in the literature, we simulate and discuss the uncertainties of Tmrt and UTCI at three stations in different climatic regions of Europe. The results show that highest negative (positive) differences to reference cases (under assumed clear-sky conditions) of up to -21°C (9°C) for Tmrt and up to -6°C (3.5°C) for UTCI occur in summer (winter) due to cloudiness. In a second step, the uncertainties of RCM simulations are analyzed: three RCMs, namely ALADIN (Aire Limitée Adaptation dynamique Développement InterNational), RegCM (REGional Climate Model) and REMO (REgional MOdel) are nested into GCMs and used for the prediction of temperature and radiation fluxes in order to estimate Tmrt and UTCI. The inter-comparison of RCM output for the three selected locations shows that biases between 0.0 and ±17.7°C (between 0.0 and ±13.3°C) for Tmrt (UTCI), and RMSE between ±0.5 and ±17.8°C (between ±0.8 and ±13.4°C) for Tmrt (UTCI) may be expected. In general the study shows that uncertainties of UTCI, due to uncertainties arising from calculations of radiation fluxes (based on NWP models) required for the prediction of Tmrt, are well below ±2°C for clear-sky cases. However, significant higher uncertainties in UTCI of up to ±6°C are found, especially when prediction of cloudiness is wrong.

  2. Comparisons of observed seasonal climate features with a winter and summer numerical simulation produced with the GLAS general circulation model

    Science.gov (United States)

    Halem, M.; Shukla, J.; Mintz, Y.; Wu, M. L.; Godbole, R.; Herman, G.; Sud, Y.

    1979-01-01

    Results are presented from numerical simulations performed with the general circulation model (GCM) for winter and summer. The monthly mean simulated fields for each integration are compared with observed geographical distributions and zonal averages. In general, the simulated sea level pressure and upper level geopotential height field agree well with the observations. Well simulated features are the winter Aleutian and Icelandic lows, the summer southwestern U.S. low, the summer and winter oceanic subtropical highs in both hemispheres, and the summer upper level Tibetan high and Atlantic ridge. The surface and upper air wind fields in the low latitudes are in good agreement with the observations. The geographical distirbutions of the Earth-atmosphere radiation balance and of the precipitation rates over the oceans are well simulated, but not all of the intensities of these features are correct. Other comparisons are shown for precipitation along the ITCZ, rediation balance, zonally averaged temperatures and zonal winds, and poleward transports of momentum and sensible heat.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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.)

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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)

  13. 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

  14. 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.

  15. Exploratory analyses for the assessment of climate change impacts on the energy production in an Amazon run-of-river hydropower plant

    Directory of Open Access Journals (Sweden)

    Guilherme Samprogna Mohor

    2015-09-01

    New hydrological insights for the region: The high inter-model variability in the climate projections drives a high variability in the projected hydrological impacts. Results indicate an increase of basin's sensitivity to climate change and vulnerability of water exploitation. Uncertainties prevent the identification of a singular optimal solution for impacts assessment. However, exploratory analysis of the plant design robustness for hydropower generation show a reduction in the energy production even under projections of increased discharge, due to plant capacity limitations. This is valuable information for stakeholders to decide about energy production strategies.

  16. 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.

  17. 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.

  18. 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)

  19. Numerical Analyses of Energetic Particles in LHD

    Energy Technology Data Exchange (ETDEWEB)

    Todo, Yasushi [National Institute for Fusion Science, Toki, Japan; Murakami, S. [Kyoto University, Japan; Yamamoto, T. [Kyoto University, Japan; Fukuyama, A. [Kyoto University, Japan; Spong, Donald A [ORNL; Yamamoto, S. [Nagoya University, Japan; Osakabe, M. [National Institute for Fusion Science, Toki, Japan; Nakajima, N. [National Institute for Fusion Science, Toki, Japan

    2010-01-01

    The confinement of energetic ions generated by neutral beam injection (NBI) and ion cyclotron resonance frequency heating is studied using GNET simulation code, in which the drift kinetic equation is solved in five-dimensional phase-space. The steady-state distributions of the energetic ions are obtained, and characteristics of the energetic-ion distribution depending on the plasma heating method are shown. The magnetic configuration effect on the energetic-ion confinement is also investigated, and it is found that the energetic-ion confinement is improved by a strong inward shift of the magnetic axis position in the major radius direction. The interaction between energetic particles and Alfven eigenmodes are investigated using the MEGA code and the AE3D code. A reduced version of the MEGA code has been developed to simulate the Alfven eigenmode (AE) evolution in the Large Helical Device (LHD) plasma with NBI and collisions taken into account. The spatial profile and frequency of the AE modes in the LHD plasma are analyzed with the AE3D code. The evolution of energetic particles and AE mode amplitude and phase are followed in a self-consistent way, while the AE spatial profiles are assumed to be constant. It is demonstrated that the AE bursts can be simulated with the new code.

  20. Climate Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Lindzen, Richard [M.I.T.

    2011-11-09

    Warming observed thus far is entirely consistent with low climate sensitivity. However, the result is ambiguous because the sources of climate change are numerous and poorly specified. Model predictions of substantial warming aredependent on positive feedbacks associated with upper level water vapor and clouds, but models are notably inadequate in dealing with clouds and the impacts of clouds and water vapor are intimately intertwined. Various approaches to measuring sensitivity based on the physics of the feedbacks will be described. The results thus far point to negative feedbacks. Problems with these approaches as well as problems with the concept of climate sensitivity will be described.

  1. 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.)

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. Challenges faced by NGOs in the political harsh climate of Zimbabwe : analysing the effects on sustainability and promotion of human rights.

    OpenAIRE

    Chakawarika, Bertha

    2011-01-01

    Non-governmental organizations (NGOs) have gained a very high status as the leading practitioners of development in Africa. African governments have reacted obscurely to the existence of these agencies. Although they recognise the economic resources NGOs can raise, they tend to resist the political pluralisation contingent to popular development action. This article describes the role of NGOs in Zimbabwe and analyses the dynamics of government-NGO relations and the effects on promotion and p...

  8. 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.

  9. Temporal scaling analysis of irradiance estimated from daily satellite data and numerical modelling

    Science.gov (United States)

    Vindel, Jose M.; Navarro, Ana A.; Valenzuela, Rita X.; Ramírez, Lourdes

    2016-11-01

    The temporal variability of global irradiance estimated from daily satellite data and numerical models has been compared for different spans of time. According to the time scale considered, a different behaviour can be expected for each climate. Indeed, for all climates and at small scale, the persistence decreases as this scale increases, but the mediterranean climate, and its continental variety, shows higher persistence than oceanic climate. The probabilities of maintaining the values of irradiance after a certain period of time have been used as a first approximation to analyse the quality of each source, according to the climate. In addition, probability distributions corresponding to variations of clearness indices measured at several stations located in different climate zones have been compared with those obtained from satellite and modelling estimations. For this work, daily radiation data from the reanalysis carried out by the European Centre for Medium-Range Weather Forecasts and from the Satellite Application Facilities on climate monitoring have been used for mainland Spain. According to the results, the temporal series estimation of irradiance is more accurate when using satellite data, independent of the climate considered. In fact, the coefficients of determination corresponding to the locations studied are always above 0.92 in the case of satellite data, while this coefficient decreases to 0.69 for some cases of the numerical model. This conclusion is more evident in oceanic climates, where the most important errors can be observed. Indeed, in this case, the RRMSE derived from the CM-SAF estimations is 20.93%, while in the numerical model, it is 48.33%. Analysis of the probabilities corresponding to variations in the clearness indices also shows a better behaviour of the satellite-derived estimates for oceanic climate. For the standard mediterranean climate, the satellite also provides better results, though the numerical model improves

  10. The Effect of Pleistocene Climate Fluctuations on Distribution of European Abalone (Haliotis tuberculata), Revealed by Combined Mitochondrial and Nuclear Marker Analyses.

    Science.gov (United States)

    Roussel, Valérie; Van Wormhoudt, Alain

    2017-04-01

    The genetic differentiation among the populations of the European abalone Haliotis tuberculata was investigated using different markers to better understand the evolutionary history and exchanges between populations. Three markers were used: mitochondrial cytochrome oxidase I (COI), the sperm lysin nuclear gene, and eight nuclear microsatellites. These markers present different characteristics concerning mutation rate and inheritance, which provided complementary information about abalone history and gene diversity. Genetic diversity and relationships among subspecies were calculated from a sample of approximately 500 individuals, collected from 17 different locations in the north-eastern Atlantic Ocean, Macaronesia, and Mediterranean Sea. COI marker was used to explore the phylogeny of the species with a network analysis and two phylogenetic methods. The analysis revealed 18 major haplotypes grouped into two distinct clades with a pairwise sequence divergence up to 3.5 %. These clades do not correspond to subspecies but revealed many contacts along Atlantic coast during the Pleistocene interglaciations. The sperm lysin gene analysis separated two different subtaxa: one associated to Macaronesian islands, and the other to all other populations. Moreover, a small population of the northern subtaxon was isolated in the Adriatic Sea-probably before the separation of the two lineages-and evolved independently. Microsatellites were analyzed by different genetics methods, including the Bayesian clustering method and migration patterns analysis. It revealed genetically distinct microsatellite patterns among populations from Mediterranean Sea, Brittany and Normandy, Morocco, and Canary and Balearic islands. Gene flow is asymmetric among the regions; the Azores and the Canary Islands are particularly isolated and have low effective population sizes. Our results support the hypothesis that climate changes since the Pleistocene glaciations have played a major role in the

  11. Uncertainties in vertical groundwater fluxes from 1-D steady state heat transport analyses caused by heterogeneity, multidimensional flow, and climate change

    Science.gov (United States)

    Irvine, Dylan J.; Cartwright, Ian; Post, Vincent E. A.; Simmons, Craig T.; Banks, Eddie W.

    2016-02-01

    Steady state 1-D analytical solutions to estimate groundwater fluxes from temperature profiles are an attractive option because they are simple to apply, with no complex boundary or initial conditions. Steady state solutions have been applied to estimate both aquifer scale fluxes as well as to estimate groundwater discharge to streams. This study explores the sources of uncertainty in flux estimates from regional scale aquifers caused by sensor precision, aquifer heterogeneity, multidimensional flow and variations in surface temperature due to climate change. Synthetic temperature profiles were generated using 2-D groundwater flow and heat transport models with homogeneous and heterogeneous hydraulic and thermal properties. Temperature profiles were analyzed assuming temperature can be determined with a precision between 0.1°C and 0.001°C. Analysis of synthetic temperature profiles show that the Bredehoeft and Papadopulos (1965) method can provide good estimates of the mean vertical Darcy flux over the length of the temperature profile. Reliable flux estimates were obtained when the ratio of vertical to horizontal flux was as low as 0.1, and in heterogeneous media, providing that temperature at the upper boundary was constant in time. However, temporal increases in surface temperature led to over-estimation of fluxes. Overestimates increased with time since the onset of, and with the rate of surface warming. Overall, the Bredehoeft and Papadopulos (1965) method may be more robust for the conditions with constant temperature distributions than previously thought, but that transient methods that account for surface warming should be used to determine fluxes in shallow aquifers.

  12. Kvalitative analyser ..

    DEFF Research Database (Denmark)

    Boolsen, Merete Watt

    bogen forklarer de fundamentale trin i forskningsprocessen og applikerer dem på udvalgte kvalitative analyser: indholdsanalyse, Grounded Theory, argumentationsanalyse og diskursanalyse......bogen forklarer de fundamentale trin i forskningsprocessen og applikerer dem på udvalgte kvalitative analyser: indholdsanalyse, Grounded Theory, argumentationsanalyse og diskursanalyse...

  13. ÉLABORATION D'UN MODÈLE DU CLIMAT DISTRIBUÉ À L'ÉCHELLE DE L'ABRI ET DE LA PLANTE EN CULTURES ORNEMENTALES SOUS SERRES : ANALYSE DES TRANSFERTS DE MASSE ET DE CHALEUR, BILANS ÉNERGÉTIQUES

    OpenAIRE

    Morille, B.

    2012-01-01

    The objectives of this thesis are to develop a numerical tool which would be able to provide exhaustive information on the evolution of the distributed climate in a greenhouse. The thesis is based on experimental and numerical approaches and aims for giving information on the main concerns of the growers: the temperature and the humidity management with a special attention giving to the reduction of the energy consumptions. This is the reason why the study considers two situations in which th...

  14. 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.

  15. 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)

  16. Numerical Simulation of Soil Moisture Variation on Climate%土壤含水量改变对气候影响的数值模拟

    Institute of Scientific and Technical Information of China (English)

    郭亚娜; 潘益农

    2011-01-01

    中国南北方水土资源配置不合理,南方水多耕地少,北方水少耕地多.南水北调工程通过跨流域的水资源合理配置,大大缓解北方水资源严重短缺问题.本文用两层嵌套的中尺度气象模式MM5及其耦合的陆面过程模式,研究调水对局地气象环境的影响.研究表明,实施南水北调后,春季和夏季北方地区土壤含水量增加、累积降水量增加,地表温度降低.夏季的土壤含水量、地表温度、累积降水量的变化幅度明显大于春季.另外干燥的土壤环境条件,对气象环境的改变更明显.春季和夏季土壤含水量变化的区域、地表温度的降低的地区都不只局限于南水北调受水区,而是散布到周边地区.另外还可以看出,在土壤含水量未改变的地区有明显的降雨量增加,最大降雨量增加区域与土壤水份的变化中心区域不重合.%Water resource appears the serious region difference between southern and northern part of China. The northern part belongs to the dry region which water is hard up; however, the supply exceeds demand that is the character of water resources in the southern part. Along with the economical development and the climatic fluctuation, the contradiction between the supply and demand for water resource in the northern part is gradually becoming serious, since 1980s. The trend of climatic fluctuation is represented by the decreasing precipitation and increasing temperature. The economical loss and the environmental degeneration become more obvious than ever before. The drought affects people's life and work seriously. Water transportation from south part to north part of China is a valid measure to resolve this problem. Through water transportation from south to north part of China, the contradiction involving water shortage could be solved. It could improve environment and accelerate the speed of social development. The change of soil moisture that influences on the local

  17. 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

  18. 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

  19. Climate Action Benefits: Electricity

    Science.gov (United States)

    This page provides background on the relationship between electricity and climate change and describes what the CIRA Electricity analyses cover. It provides links to the subsectors Electricity Demand and Electricity Supply.

  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. 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).

  2. 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.)

  3. Approaching the Edge of Abrupt Climate Change

    Science.gov (United States)

    Ramadhin, C.; Yi, C.

    2015-12-01

    The phenomenon of Abrupt Climate Change (ACC) became evident as paleoclimate data analyses began revealing that Earth's climate has the ability to rapidly switch from one state to the next in just a few decades after thresholds are crossed. Previously paleo-climatologists thought these switches were gradual but now there is growing concern to identify thresholds and the dominant feedback mechanisms that propel systems toward thresholds. Current human civilization relies heavily on climate stability and ACC threatens immense disruption with potentially disastrous consequences for all ecosystems. Therefore, prediction of the climate system's approach to threshold values would prove vital for the resilience of civilization through development of appropriate adaptation strategies when that shift occurs. Numerous studies now establish that earth systems are experiencing dramatic changes both by system interactions and anthropogenic sources adding urgency for comprehensive knowledge of tipping point identification. Despite this, predictions are difficult due to the immensity of interactions among feedback mechanisms. In this paper, we attempt to narrow this broad spectrum of critical feedback mechanisms by reviewing several publications on role of feedbacks in initiating past climate transitions establishing the most critical ones and significance in current climate changes. Using a compilation of paleoclimate datasets we compared the rates of deglaciations with that of glacial inceptions, which are approximately 5-10 times slower. We hypothesize that the critical feedbacks are unique to each type of transition such that warmings are dominated by the ice-albedo feedback while coolings are a combination of temperature - CO2 and temperature-precipitation followed by the ice-albedo feedbacks. Additionally, we propose the existence of a commonality in the dominant trigger feedbacks for astronomical and millennial timescale abrupt climate shifts and as such future studies

  4. 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...

  5. 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)

  6. Future climate resources for tourism in Europe based on the daily Tourism Climatic Index

    NARCIS (Netherlands)

    Perch-Nielsen, S.; Amelung, B.; Knutti, R.

    2010-01-01

    Climate is an important resource for many types of tourism. One of several metrics for the suitability of climate for sightseeing is Mieczkowski’s “Tourism Climatic Index” (TCI), which summarizes and combines seven climate variables. By means of the TCI, we analyse the present climate resources for

  7. 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...

  8. 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

  9. Mathematical and numerical analysis of the resistive magnetohydrodynamics system with self-generated magnetic field terms; Analyse mathematique et numerique du systeme de la magnetohydrodynamique resistive avec termes de champ magnetique auto-genere

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Marc

    2011-10-14

    This work is devoted to the construction of numerical methods that allow the accurate simulation of inertial confinement fusion (ICF) implosion processes by taking self-generated magnetic field terms into account. In the sequel, we first derive a two-temperature resistive magnetohydrodynamics model and describe the considered closure relations. The resulting system of equations is then split in several subsystems according to the nature of the underlying mathematical operator. Adequate numerical methods are then proposed for each of these subsystems. Particular attention is paid to the development of finite volume schemes for the hyperbolic operator which actually is the hydrodynamics or ideal magnetohydrodynamics system depending on whether magnetic fields are considered or not. More precisely, a new class of high-order accurate dimensionally split schemes for structured meshes is proposed using the Lagrange re-map formalism. One of these schemes' most innovative features is that they have been designed in order to take advantage of modern massively parallel computer architectures. This property can for example be illustrated by the dimensionally split approach or the use of artificial viscosity techniques and is practically highlighted by sequential performance and parallel efficiency figures. Hyperbolic schemes are then combined with finite volume methods for dealing with the thermal and resistive conduction operators and taking magnetic field generation into account. In order to study the characteristics and effects of self-generated magnetic field terms, simulation results are finally proposed with the complete two-temperature resistive magnetohydrodynamics model on a test problem that represents the state of an ICF capsule at the beginning of the deceleration phase. (author)

  10. 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<

  11. 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…

  12. 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.

  13. Numerical Macaulification

    CERN Document Server

    Migliore, Juan

    2012-01-01

    An unpublished example due to Joe Harris from 1983 (or earlier) gave two smooth space curves with the same Hilbert function, but one of the curves was arithmetically Cohen-Macaulay (ACM) and the other was not. Starting with an arbitrary homogeneous ideal in any number of variables, we give two constructions, each of which produces, in a finite number of steps, an ideal with the Hilbert function of a codimension two ACM subscheme. We call the subscheme associated to such an ideal "numerically ACM." We study the connections between these two constructions, and in particular show that they produce ideals with the same Hilbert function. We call the resulting ideal from either construction a "numerical Macaulification" of the original ideal. Specializing to the case where the ideals are unmixed of codimension two, we show that (a) every even liaison class, $\\mathcal L$, contains numerically ACM subschemes, (b) the subset, $\\mathcal M$, of numerically ACM subschemes in $\\mathcal L$ has, by itself, a Lazarsfeld-Rao ...

  14. Adapting California’s ecosystems to a changing climate

    Science.gov (United States)

    Elizabeth Chornesky,; David Ackerly,; Paul Beier,; Frank Davis,; Flint, Lorraine E.; Lawler, Joshua J.; Moyle, Peter B.; Moritz, Max A.; Scoonover, Mary; Byrd, Kristin B.; Alvarez, Pelayo; Heller, Nicole E.; Micheli, Elisabeth; Weiss, Stuart

    2017-01-01

    Significant efforts are underway to translate improved understanding of how climate change is altering ecosystems into practical actions for sustaining ecosystem functions and benefits. We explore this transition in California, where adaptation and mitigation are advancing relatively rapidly, through four case studies that span large spatial domains and encompass diverse ecological systems, institutions, ownerships, and policies. The case studies demonstrate the context specificity of societal efforts to adapt ecosystems to climate change and involve applications of diverse scientific tools (e.g., scenario analyses, downscaled climate projections, ecological and connectivity models) tailored to specific planning and management situations (alternative energy siting, wetland management, rangeland management, open space planning). They illustrate how existing institutional and policy frameworks provide numerous opportunities to advance adaptation related to ecosystems and suggest that progress is likely to be greatest when scientific knowledge is integrated into collective planning and when supportive policies and financing enable action.

  15. Theoretical and Numerical Analyses of Fatigue Crack Growth and Rupture of Diseased Vessel%动脉硬化血管疲劳裂纹扩展与破裂理论与数值分析

    Institute of Scientific and Technical Information of China (English)

    李志勇; 裴璇

    2012-01-01

    动脉粥样硬化的斑块破裂是中风和心肌梗死的主要原因.斑块破裂与血液和剪切应力存在一定的关系.基于血管是天然的周期性低应力环境,本文将血管斑块破裂处理成一个疲劳问题,将血管简化成圆筒,探讨斑块中的裂纹扩展与疲劳破坏,并考查血管内外径比、血栓、血压等因素对疲劳寿命的影响.应力强度因子的计算采用经典圆筒内壁单边裂纹的理论公式,疲劳裂纹扩展利用著名的Paris法则,并利用数值方法求解裂纹扩展过程.研究发现,在血管内外径比不变时,内径的大小对疲劳裂纹扩展的影响几乎可以忽略不计;血栓形成会增加血管壁厚,降低应力集中,该单一因素在疲劳意义上反而会有利;血压对血管疲劳寿命的影响非常大,成指数次减小或增加.%Plaque rupture is a major cause of heart attack. Mechanical factors including blood pressure and shear stress have been found to be related to the rupture risk. The blood vessel is naturally under a periodical and low-level pressure stress state, therefore, the plaque rupture can be treated as a fatigue problem. By simplifying the blood vessel as a cylinder, the crack propagation and the fatigue rupture are investigated. The theoretical solution for an edge crack in a classical cylinder is used to calculate the Stress Intensity Factor (SIF) with the Paris Law being utilized to determine the crack growth rate. The fatigue crack growth is numerically simulated. The various factors that may influence the fatigue life are studied. The results show that when the ratio of the external radius to the internal radius is fixed, the effect of the internal radius on the fatigue crack growth can be neglected; the thrombus with an increase of the wall thickness will reduce the stress concentration, this single factor may have a positive effect to the vascular life from the point view of fatigue; the blood pressure has a great effect on the

  16. 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

  17. 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

  18. Climate protection by means of state aids. An analysis of the state aid framework of energy political and environmental political measures; Klimaschutz durch Beihilfen. Eine Analyse des beihilferechtlichen Rahmens fuer energie- und umweltpolitische Massnahmen

    Energy Technology Data Exchange (ETDEWEB)

    Behlau, Volker; Lutz, Jana; Schuett, Manuel

    2012-07-01

    The authors of the book under consideration report on an analysis of the state aid framework of energy political and environmental political measures. This book consists of the following chapters: (1) Subsidies as an instrument of the law on climate protection and environmental protection (V. Behlau, J. Lutz, M. Schuett); (2) The material prohibition of State aid of Art. 107 AEUV (Treaty on the Functioning of the European Union) (V. Behlau); (3) State aids for the environmental protection in the legislative practice and decision practice of the European Commission (J. Lutz, V. Behlau, M. Schuett, F. Bartl); (4) State aids for the environmental protection in the European procedural law (M. Schuett); (5) Altmark Trans, Ferring and Co. - Is the leading back of the state aid regime also economically interesting for climate protection relevant measures? (V. Behlau, J. Lutz, S. Sobotta, M. Schuett); (6) Concluding remarks (V. Behlau, J. Lutz, M. Schuett).

  19. 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.

  20. Numerical Investigation of Boiling

    Science.gov (United States)

    Sagan, Michael; Tanguy, Sebastien; Colin, Catherine

    2012-11-01

    In this work, boiling is numerically investigated, using two phase flow direct numerical simulation based on a level set / Ghost Fluid method. Nucleate boiling implies both thermal issue and multiphase dynamics issues at different scales and at different stages of bubble growth. As a result, the different phenomena are investigated separately, considering their nature and the scale at which they occur. First, boiling of a static bubble immersed in an overheated liquid is analysed. Numerical simulations have been performed at different Jakob numbers in the case of strong density discontinuity through the interface. The results show a good agreement on bubble radius evolution between the theoretical evolution and numerical simulation. After the validation of the code for the Scriven test case, interaction of a bubble with a wall is studied. A numerical method taking into account contact angle is evaluated by comparing simulations of the spreading of a liquid droplet impacting on a plate, with experimental data. Then the heat transfer near the contact line is investigated, and simulations of nucleate boiling are performed considering different contact angles values. Finally, the relevance of including a model to take into account the evaporation of the micro layer is discussed.

  1. 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....

  2. Physical fundamentals of climate and climate models. Main research programme of Deutsche Forschungsgemeinschaft, 1978-1985. Final report. Physikalische Grundlagen des Klimas und Klimamodelle. Forschungsschwerpunkt der Deutschen Forschungsgemeinschaft, 1978-1985. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Wippermann, F.

    1988-01-01

    The results of the main point of research 'Physical Fundamentals of Climate and Climate Models' of the German Research Council (DFG) are summarized. Time series analyses, sensitivity of the global climate, blockings, variability of global pressure fields and geopotential fields, circulation models as well as statistical tests of theories are demonstrated by examples under the heading 'global climate'. In the second part (mesoscale climate) the regional field experiments MESOKLIP, DISKUS, PUKK and MERKUR are described and single phenomena and their numeric simulation are dealt with. This includes the canalization of the air flow in valleys, thermal wind systems as well as ground layer jet streams. A bibliography contains original papers, theses and reports written within the framework of the research progamme.

  3. 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

  4. 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...

  5. Cervical Spine Injuries - Numerical Analyses and Statistical Survey

    OpenAIRE

    2002-01-01

    Injuries to the neck, or cervical region, are very importantsince there is a potential risk of damage to the spinal cord.Any neck injury can have devastating if not life threateningconsequences. High-speed transportation as well as leisure-timeadventures have increased the number of serious neck injuriesand made us increasingly aware of its consequences.Surveillance systems and epidemiological studies are importantprerequisites in defining the scope of the problem. Thedevelopment of mechanica...

  6. 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

  7. Formulation of an ocean model for global climate simulations

    Directory of Open Access Journals (Sweden)

    S. M. Griffies

    2005-01-01

    Full Text Available This paper summarizes the formulation of the ocean component to the Geophysical Fluid Dynamics Laboratory's (GFDL climate model used for the 4th IPCC Assessment (AR4 of global climate change. In particular, it reviews the numerical schemes and physical parameterizations that make up an ocean climate model and how these schemes are pieced together for use in a state-of-the-art climate model. Features of the model described here include the following: (1 tripolar grid to resolve the Arctic Ocean without polar filtering, (2 partial bottom step representation of topography to better represent topographically influenced advective and wave processes, (3 more accurate equation of state, (4 three-dimensional flux limited tracer advection to reduce overshoots and undershoots, (5 incorporation of regional climatological variability in shortwave penetration, (6 neutral physics parameterization for representation of the pathways of tracer transport, (7 staggered time stepping for tracer conservation and numerical efficiency, (8 anisotropic horizontal viscosities for representation of equatorial currents, (9 parameterization of exchange with marginal seas, (10 incorporation of a free surface that accomodates a dynamic ice model and wave propagation, (11 transport of water across the ocean free surface to eliminate unphysical ``virtual tracer flux' methods, (12 parameterization of tidal mixing on continental shelves. We also present preliminary analyses of two particularly important sensitivities isolated during the development process, namely the details of how parameterized subgridscale eddies transport momentum and tracers.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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)

  13. 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.

  14. 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.

  15. 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

  16. Climate change and skin.

    Science.gov (United States)

    Balato, N; Ayala, F; Megna, M; Balato, A; Patruno, C

    2013-02-01

    Global climate appears to be changing at an unprecedented rate. Climate change can be caused by several factors that include variations in solar radiation received by earth, oceanic processes (such as oceanic circulation), plate tectonics, and volcanic eruptions, as well as human-induced alterations of the natural world. Many human activities, such as the use of fossil fuel and the consequent accumulation of greenhouse gases in the atmosphere, land consumption, deforestation, industrial processes, as well as some agriculture practices are contributing to global climate change. Indeed, many authors have reported on the current trend towards global warming (average surface temperature has augmented by 0.6 °C over the past 100 years), decreased precipitation, atmospheric humidity changes, and global rise in extreme climatic events. The magnitude and cause of these changes and their impact on human activity have become important matters of debate worldwide, representing climate change as one of the greatest challenges of the modern age. Although many articles have been written based on observations and various predictive models of how climate change could affect social, economic and health systems, only few studies exist about the effects of this change on skin physiology and diseases. However, the skin is the most exposed organ to environment; therefore, cutaneous diseases are inclined to have a high sensitivity to climate. For example, global warming, deforestation and changes in precipitation have been linked to variations in the geographical distribution of vectors of some infectious diseases (leishmaniasis, lyme disease, etc) by changing their spread, whereas warm and humid environment can also encourage the colonization of the skin by bacteria and fungi. The present review focuses on the wide and complex relationship between climate change and dermatology, showing the numerous factors that are contributing to modify the incidence and the clinical pattern of many

  17. 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

  18. 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...

  19. 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...

  20. 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.……

  1. Ultrascale Visualization of Climate Data

    Science.gov (United States)

    Williams, Dean N.; Bremer, Timo; Doutriaux, Charles; Patchett, John; Williams, Sean; Shipman, Galen; Miller, Ross; Pugmire, David R.; Smith, Brian; Steed, Chad; Bethel, E. Wes; Childs, Hank; Krishnan, Harinarayan; Prabhat; Wehner, Michael; Silva, Claudio T.; Santos, Emanuele; Koop, David; Ellqvist, Tommy; Poco, Jorge; Gevecki, Berk; Chaudhary, Aashish; Bauer, Andy; Potter, Gerald L.; Maxwell, Thomas P.

    2013-01-01

    Fueled by exponential increases in the computational and storage capabilities of high-performance computing platforms, climate simulations are evolving toward higher numerical fidelity, complexity, volume, and dimensionality. These technological breakthroughs are coming at a time of exponential growth in climate data, with estimates of hundreds of exabytes by 2020. To meet the challenges and exploit the opportunities that such explosive growth affords, a consortium of four national laboratories, two universities, a government agency, and two private companies formed to explore the next wave in climate science. Working in close collaboration with domain experts, the Ultrascale Visualization Climate Data Analysis Tools (UV-CDAT) project aims to provide high-level solutions to a variety of climate data analysis and visualization problems.

  2. 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...

  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. 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.

  5. 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.

  6. 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.

  7. 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

  8. Climate change matters.

    Science.gov (United States)

    Macpherson, Cheryl Cox

    2014-04-01

    One manifestation of climate change is the increasingly severe extreme weather that causes injury, illness and death through heat stress, air pollution, infectious disease and other means. Leading health organisations around the world are responding to the related water and food shortages and volatility of energy and agriculture prices that threaten health and health economics. Environmental and climate ethics highlight the associated challenges to human rights and distributive justice but rarely address health or encompass bioethical methods or analyses. Public health ethics and its broader umbrella, bioethics, remain relatively silent on climate change. Meanwhile global population growth creates more people who aspire to Western lifestyles and unrestrained socioeconomic growth. Fulfilling these aspirations generates more emissions; worsens climate change; and undermines virtues and values that engender appreciation of, and protections for, natural resources. Greater understanding of how virtues and values are evolving in different contexts, and the associated consequences, might nudge the individual and collective priorities that inform public policy toward embracing stewardship and responsibility for environmental resources necessary to health. Instead of neglecting climate change and related policy, public health ethics and bioethics should explore these issues; bring transparency to the tradeoffs that permit emissions to continue at current rates; and offer deeper understanding about what is at stake and what it means to live a good life in today's world.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bhatti, N.; Cirillo, R.R. [Argonne National Lab., IL (United States); Dixon, R.K. [U.S. Country Studies Program, Washington, DC (United States)] [and others

    1995-12-31

    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. 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

  11. 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...

  12. Numerical Limit Analysis of Precast Concrete Structures

    DEFF Research Database (Denmark)

    Herfelt, Morten Andersen; Poulsen, Peter Noe; Hoang, Linh Cao

    2016-01-01

    optimisation as well as material optimisation is given and a four-storey shear wall is analysed using load optimisation. The analysis yields a capacity more than three times larger than the design load for the critical load case, and the collapse mode and stress distribution are analysed. Finally, numerical...

  13. 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 holdings...

  14. Climate Change

    Science.gov (United States)

    ... events, such as hurricanes and wildfires. These can cause death, injuries, stress, and mental health problems. Researchers are studying the best ways to lessen climate change and reduce its impact on our health. NIH: ...

  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. A Robust, Scalable Framework for Conducting Climate Change Susceptibility Analyses

    Science.gov (United States)

    2014-05-01

    including changes in flowering phenology (Bradley et al. 1999), temperature regimes (Barber et al. 2000), and hydrologic cycles (IPCC 2007, Knapp et...average and variation of susceptibility metrics can be calculated to evaluate and compare regions of interest (Figure 1). ERDC/EL TN-14-1 May 2014...average susceptibility scores as well as the variation in the scores across the scenarios can give natural resource managers the ability to prioritize

  17. 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…

  18. 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.

  19. Climate Models

    Science.gov (United States)

    Druyan, Leonard M.

    2012-01-01

    Climate models is a very broad topic, so a single volume can only offer a small sampling of relevant research activities. This volume of 14 chapters includes descriptions of a variety of modeling studies for a variety of geographic regions by an international roster of authors. The climate research community generally uses the rubric climate models to refer to organized sets of computer instructions that produce simulations of climate evolution. The code is based on physical relationships that describe the shared variability of meteorological parameters such as temperature, humidity, precipitation rate, circulation, radiation fluxes, etc. Three-dimensional climate models are integrated over time in order to compute the temporal and spatial variations of these parameters. Model domains can be global or regional and the horizontal and vertical resolutions of the computational grid vary from model to model. Considering the entire climate system requires accounting for interactions between solar insolation, atmospheric, oceanic and continental processes, the latter including land hydrology and vegetation. Model simulations may concentrate on one or more of these components, but the most sophisticated models will estimate the mutual interactions of all of these environments. Advances in computer technology have prompted investments in more complex model configurations that consider more phenomena interactions than were possible with yesterday s computers. However, not every attempt to add to the computational layers is rewarded by better model performance. Extensive research is required to test and document any advantages gained by greater sophistication in model formulation. One purpose for publishing climate model research results is to present purported advances for evaluation by the scientific community.

  20. 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

  1. Quantifying the impact of model inaccuracy in climate change impact assessment studies using an agro-hydrological model

    Directory of Open Access Journals (Sweden)

    P. Droogers

    2008-04-01

    Full Text Available Numerical simulation models are frequently applied to assess the impact of climate change on hydrology and agriculture. A common hypothesis is that unavoidable model errors are reflected in the reference situation as well as in the climate change situation so that by comparing reference to scenario model errors will level out. For a polder in The Netherlands an innovative procedure has been introduced, referred to as the Model-Scenario-Ratio (MSR, to express model inaccuracy on climate change impact assessment studies based on simulation models comparing a reference situation to a climate change situation. The SWAP (Soil Water Atmosphere Plant model was used for the case study and the reference situation was compared to two climate change scenarios. MSR values close to 1, indicating that impact assessment is mainly a function of the scenario itself rather than of the quality of the model, were found for most indicators evaluated. A climate change scenario with enhanced drought conditions and indicators based on threshold values showed lower MSR values, indicating that model accuracy is an important component of the climate change impact assessment. It was concluded that the MSR approach can be applied easily and will lead to more robust impact assessment analyses.

  2. IPCC A1B情景下中国西南地区气候变化的数值模拟%Numerical Simulations of Climate Change under IPCC A1B Scenario in Southwestern China

    Institute of Scientific and Technical Information of China (English)

    吴迪; 裴源生; 赵勇; 肖伟华

    2012-01-01

    利用ECHAM5/MPI-OM全球海气耦合模式模拟的当代(1986-2000年)和IPCC A1B情景下未来(2011-2025年)2×15a的模拟输出格点场资料,驱动20 km高水平分辨率区域气候模式RegCM3进行西南地区气候变化的数值模拟,主要分析未来地面温度和降水的可能变化。结果表明:①通过与32个地面气象站观测资料和CRU资料对比分析,RegCM3能够很好的模拟研究区基准时段地面温度和降水的局地分布特征。②A1B情景下未来西南地区年、四季平均温度均明显增加,北部温度变化幅度大于南部。③最高/最低温度一致升高,冬季最高/最低温度变化幅度大于夏季;年、秋冬季降水有所增加,冬季降水增加明显,而春夏季降水略有减少。④研究区未来春夏季温度升高、降水减少的趋势可能导致局部地区高温、干旱等极端天气的可能性增大;同时冬季降水增加,可能加重局部地区洪涝灾害的风险。%Climate change over southwestern China is simulated by a regional climate model(RegCM3),using the output from a global coupled atmosphere-ocean model(ECHAM5/MPI-OM) as lateral and surface boundary conditions.Two sets of 15 years of simulations at 20-km gird resolution for present days(1986-2000) and future(2011-2025,under IPCC_A1B scenario) are conducted to analyze the effects of surface air temperature and precipitation on the drought as a focal area.Results show that RegCM3 can reproduce well the spatial distribution of surface air temperature and precipitation in southwestern China compared with the observed data of 32 meteorological stations and grid data of CRU,and simulated annual and summer precipitation is much higher than winter precipitation.The simulated precipitation in winter is higher than observed values.During 2011-2025,there might be a remarkably warming either annually or in other seasons.The temperature change in the northern region is bigger than that in the

  3. 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

  4. 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...

  5. Risk Aversion, Intergenerational Equity and Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Ha-Duong, Minh [CNRS-CIRED, Paris (France); Treich, N. [LEERNA-INRA, University of Toulouse (France)

    2004-06-01

    The paper investigates a climate-economy model with an iso-elastic welfare function in which one parameter {gamma} measures relative risk-aversion and a distinct parameter {rho} measures resistance to intertemporal substitution. We show both theoretically and numerically that climate policy responds differently to variations in the two parameters. In particular, we show that higher {gamma} but lower {rho} leads to increase emissions control. We also argue that climate-economy models based on intertemporal expected utility maximization, i.e. models where {gamma} ={rho}, may misinterpret the sensitivity of the climate policy to risk-aversion.

  6. 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....

  7. Climate and society: passed climates, man era, future climate: essential reference marks; Climat et societe: Climats passes, passage de l'homme, climat futur: reperes essentiels

    Energy Technology Data Exchange (ETDEWEB)

    Melieres, M.A.; Marechal, Ch.

    2010-07-01

    This teaching book takes stock of the climate change question which has moved beyond the simple scientific framework. Man will play a key role in the changes to come and the choices he is going to make will have a major impact on our environment and on our societies. The aim of this book is to draw out the essential marks from the multiple disciplines involved in the study of climate change in order to get a global overview of the question. Starting from simple mechanisms showing up the driving components of the climate equilibrium (like the greenhouse effect), the authors analyse the climates of the past, and describe the different causes of the actual climate change and its possible evolution in the future. The global nature of the climate warming in progress is demonstrated and some of its actual impacts on the environment are shown up. The importance of the anthropic influence in this change is underlined as well as the stakes of the mastery of our greenhouse gas emissions. (J.S.)

  8. Seasonal Variability of Wind Climate in Hungary

    Directory of Open Access Journals (Sweden)

    PÉLINÉ NÉMETH, Csilla

    2011-01-01

    Full Text Available One of the most important effects of climate variability and climate change may comefrom changes in the intensity and frequency of climatic extremes. Responding to the need of newclimatologic analyses, complex wind field research was carried out to study and provide reliableinformation about the state and variability of wind climate in Hungary. First of all, special attentionwas paid on creation of a high quality, homogeneous data series. The research is based on 36-yearlong(1975–2010 wind data series of 36 Hungarian synoptic meteorological stations. The means andextremes of near-surface wind conditions assist in estimating the regional effects of climate change,therefore a complex wind climate analysis was carried out. Spatial and temporal distribution of meanand extreme wind characteristics were estimated; wind extremes and trends were interpolated andmapped over the country. Furthermore, measured and ERA Interim reanalysis data were compared inorder to estimate the effects of regional climate change.

  9. 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…

  10. 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,

  11. Contesting Citizenship: Comparative Analyses

    DEFF Research Database (Denmark)

    Siim, Birte; Squires, Judith

    2007-01-01

    . Comparative citizenship analyses need to be considered in relation to multipleinequalities and their intersections and to multiple governance and trans-national organisinf. This, in turn, suggests that comparative citizenship analysis needs to consider new spaces in which struggles for equal citizenship occur...

  12. 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

  13. 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.

  14. 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.

  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. 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

  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. 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?

  19. Mode analysis of numerical geodynamo models

    CERN Document Server

    Schrinner, Martin; Hoyng, Peter

    2011-01-01

    It has been suggested in Hoyng (2009) that dynamo action can be analysed by expansion of the magnetic field into dynamo modes and statistical evaluation of the mode coefficients. We here validate this method by analysing a numerical geodynamo model and comparing the numerically derived mean mode coefficients with the theoretical predictions. The model belongs to the class of kinematically stable dynamos with a dominating axisymmetric, antisymmetric with respect to the equator and non-periodic fundamental dynamo mode. The analysis requires a number of steps: the computation of the so-called dynamo coefficients, the derivation of the temporally and azimuthally averaged dynamo eigenmodes and the decomposition of the magnetic field of the numerical geodynamo model into the eigenmodes. For the determination of the theoretical mode excitation levels the turbulent velocity field needs to be projected on the dynamo eigenmodes. We compare the theoretically and numerically derived mean mode coefficients and find reason...

  20. Extracting scaling laws from numerical dynamo models

    CERN Document Server

    Stelzer, Z

    2013-01-01

    Earth's magnetic field is generated by processes in the electrically conducting, liquid outer core, subsumed under the term `geodynamo'. In the last decades, great effort has been put into the numerical simulation of core dynamics following from the magnetohydrodynamic (MHD) equations. However, the numerical simulations are far from Earth's core in terms of several control parameters. Different scaling analyses found simple scaling laws for quantities like heat transport, flow velocity, magnetic field strength and magnetic dissipation time. We use an extensive dataset of 116 numerical dynamo models compiled by Christensen and co-workers to analyse these scalings from a rigorous model selection point of view. Our method of choice is leave-one-out cross-validation which rates models according to their predictive abilities. In contrast to earlier results, we find that diffusive processes are not negligible for the flow velocity and magnetic field strength in the numerical dynamos. Also the scaling of the magneti...

  1. Analysing Access Control Specifications

    DEFF Research Database (Denmark)

    Probst, Christian W.; Hansen, René Rydhof

    2009-01-01

    . Recent events have revealed intimate knowledge of surveillance and control systems on the side of the attacker, making it often impossible to deduce the identity of an inside attacker from logged data. In this work we present an approach that analyses the access control configuration to identify the set......When prosecuting crimes, the main question to answer is often who had a motive and the possibility to commit the crime. When investigating cyber crimes, the question of possibility is often hard to answer, as in a networked system almost any location can be accessed from almost anywhere. The most...... of credentials needed to reach a certain location in a system. This knowledge allows to identify a set of (inside) actors who have the possibility to commit an insider attack at that location. This has immediate applications in analysing log files, but also nontechnical applications such as identifying possible...

  2. 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...

  3. 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.

  4. The pace of shifting climate in marine and terrestrial ecosystems

    DEFF Research Database (Denmark)

    Burrows, Michael T.; Schoeman, David S.; Buckley, Lauren B.

    2011-01-01

    Climate change challenges organisms to adapt or move to track changes in environments in space and time. We used two measures of thermal shifts from analyses of global temperatures over the past 50 years to describe the pace of climate change that species should track: the velocity of climate cha...

  5. 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

  6. 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.

  7. 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.)

  8. 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.

  9. Strengthening Climate Services Capabilities and Regional Engagement at NOAA's National Climatic Data Center

    Science.gov (United States)

    Shea, E.

    2008-12-01

    The demand for sector-based climate information is rapidly expanding. In order to support this demand, it is crucial that climate information is managed in an effective, efficient, and user-conscious manner. NOAA's National Climatic Data Center is working closely with numerous partners to develop a comprehensive interface that is authoritative, accessible, and responsive to a variety of sectors, stakeholders, and other users. This talk will explore these dynamics and activities, with additional perspectives on climate services derived from the regional and global experiences of the NOAA Integrated Data and Environmental Applications (IDEA) Center in the Pacific. The author will explore the importance of engaging partners and customers in the development, implementation and emergence of a national climate service program. The presentation will draw on the author's experience in climate science and risk management programs in the Pacific, development of regional and national climate services programs and insights emerging from climate services development efforts in NCDC. In this context, the author will briefly discuss some of guiding principles for effective climate services and applications including: - Early and continuous dialogue, partnership and collaboration with users/customers; - Establishing and sustaining trust and credibility through a program of shared learning and joint problem- solving; - Understanding the societal context for climate risk management and using a problem-focused approach to the development of products and services; - Addressing information needs along a continuum of timescales from extreme events to long-term change; and - Embedding education, outreach and communications activities as critical program elements in effective climate services. By way of examples, the author will reference lessons learned from: early Pacific Island climate forecast applications and climate assessment activities; the implementation of the Pacific Climate

  10. Climate change risk perception and communication: addressing a critical moment?

    Science.gov (United States)

    Pidgeon, Nick

    2012-06-01

    Climate change is an increasingly salient issue for societies and policy-makers worldwide. It now raises fundamental interdisciplinary issues of risk and uncertainty analysis and communication. The growing scientific consensus over the anthropogenic causes of climate change appears to sit at odds with the increasing use of risk discourses in policy: for example, to aid in climate adaptation decision making. All of this points to a need for a fundamental revision of our conceptualization of what it is to do climate risk communication. This Special Collection comprises seven papers stimulated by a workshop on "Climate Risk Perceptions and Communication" held at Cumberland Lodge Windsor in 2010. Topics addressed include climate uncertainties, images and the media, communication and public engagement, uncertainty transfer in climate communication, the role of emotions, localization of hazard impacts, and longitudinal analyses of climate perceptions. Climate change risk perceptions and communication work is critical for future climate policy and decisions.

  11. 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.

  12. 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.

  13. 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.

  14. Multilocus phylogenetic and geospatial analyses illuminate diversification patterns and the biogeographic history of Malagasy endemic plated lizards (Gerrhosauridae: Zonosaurinae).

    Science.gov (United States)

    Blair, C; Noonan, B P; Brown, J L; Raselimanana, A P; Vences, M; Yoder, A D

    2015-02-01

    Although numerous studies have attempted to find single unifying mechanisms for generating Madagascar's unique flora and fauna, little consensus has been reached regarding the relative importance of climatic, geologic and ecological processes as catalysts of diversification of the region's unique biota. Rather, recent work has shown that both biological and physical drivers of diversification are best analysed in a case-by-case setting with attention focused on the ecological and life-history requirements of the specific phylogenetic lineage under investigation. Here, we utilize a comprehensive analytical approach to examine evolutionary drivers and elucidate the biogeographic history of Malagasy plated lizards (Zonosaurinae). Data from three genes are combined with fossil information to construct time-calibrated species trees for zonosaurines and their African relatives, which are used to test alternative diversification hypotheses. Methods are utilized for explicitly incorporating phylogenetic uncertainty into downstream analyses. Species distribution models are created for 14 of 19 currently recognized species, which are then used to estimate spatial patterns of species richness and endemicity. Spatially explicit analyses are employed to correlate patterns of diversity with both topographic heterogeneity and climatic stability through geologic time. We then use inferred geographic ranges to estimate the biogeographic history of zonosaurines within each of Madagascar's major biomes. Results suggest constant Neogene and Quaternary speciation with divergence from the African most recent common ancestor ~30 million years ago when oceanic currents and African rivers facilitated dispersal. Spatial patterns of diversity appear concentrated along coastal regions of northern and southern Madagascar. We find no relationship between either topographic heterogeneity or climatic stability and patterns of diversity. Ancestral state reconstructions suggest that western dry

  15. 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.

  16. Quantifying climatic variability in monsoonal northern China over the last 2200 years and its role in driving Chinese dynastic changes

    Science.gov (United States)

    Li, Jianyong; Dodson, John; Yan, Hong; Zhang, David D.; Zhang, Xiaojian; Xu, Qinghai; Lee, Harry F.; Pei, Qing; Cheng, Bo; Li, Chunhai; Ni, Jian; Sun, Aizhi; Lu, Fengyan; Zong, Yongqiang

    2017-03-01

    Our understanding on the spatial-temporal patterns of climatic variability over the last few millennia in the East Asian monsoon-dominated northern China (NC), and its role at a macro-scale in affecting the prosperity and depression of Chinese dynasties is limited. Quantitative high-resolution, regionally-synthesized palaeoclimatic reconstructions as well as simulations, and numerical analyses of their relationships with various fine-scale, numerical agro-ecological, social-economic, and geo-political historical records during the period of China's history, are presented here for NC. We utilize pollen data together with climate modeling to reconstruct and simulate decadal- to centennial-scale variations in precipitation or temperature for NC during the last 2200 years (-200-2000 AD). We find an overall cyclic-pattern (wet/warm or dry/cold) in the precipitation and temperature anomalies on centennial- to millennial-scale that can be likely considered as a representative for the entire NC by comparison with other related climatic records. We suggest that solar activity may play a key role in driving the climatic fluctuations in NC during the last 22 centuries, with its quasi ∼100, 50, 23, or 22-year periodicity clearly identified in our climatic reconstructions. We employ variation partitioning and redundancy analysis to quantify the independent effects of climatic factors on accounting for the total variation of 17 fine-grained numerical Chinese historical records. We quantitatively illustrate that precipitation (67.4%) may have been more important than temperature (32.5%) in causing the overall agro-ecological and macro-geopolitical shifts in imperial China with NC as the central ruling region and an agricultural heartland over the last 2200 years.

  17. Mathematical paradigms of climate science

    CERN Document Server

    Cannarsa, Piermarco; Jones, Christopher; Portaluri, Alessandro

    2016-01-01

    This book, featuring a truly interdisciplinary approach, provides an overview of cutting-edge mathematical theories and techniques that promise to play a central role in climate science. It brings together some of the most interesting overview lectures given by the invited speakers at an important workshop held in Rome in 2013 as a part of MPE2013 (“Mathematics of Planet Earth 2013”). The aim of the workshop was to foster the interaction between climate scientists and mathematicians active in various fields linked to climate sciences, such as dynamical systems, partial differential equations, control theory, stochastic systems, and numerical analysis. Mathematics and statistics already play a central role in this area. Likewise, computer science must have a say in the efforts to simulate the Earth’s environment on the unprecedented scale of petabytes. In the context of such complexity, new mathematical tools are needed to organize and simplify the approach. The growing importance of data assimilation te...

  18. 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.

  19. 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.

  20. 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.

  1. Climate - Options for broadening climate policy

    NARCIS (Netherlands)

    Aerts JCJH; Asselt H van; Bakker SJA; Bayangos V; Beers C van; Berk MM; Biermann F; Bouwer LM; Bree L van; Coninck HC de; Dorland K; Elzen ME den; Gupta J; Heemst J van; Jansen JC; Kok MTJ; Nabuurs GJ; Veraert J; Verhagen A; Kok MTJ; Coninck HC de; ECN; KMD

    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

  2. The value of climate measures; Verdien av klimatiltak

    Energy Technology Data Exchange (ETDEWEB)

    Aaheim, H.A.

    1996-02-01

    This report discusses international studies of the cost and usefulness of climate measures. Studies of the value of carrying out climate measures can be classified in two broad categories. One category analyses the cost of achieving defined goals about emission of climate gases, usually limited to CO{sub 2} emission. These are sometimes referred to as studies of cost-effectiveness. The other category tries to find measures giving net profit, and this type of studies are the most demanding. Micro-oriented analyses lay stress on the description of physical changes such as properties of specific technologies and physical damage by climate changes. Then the changes are valued according to market prices. Macro-economic analyses, on the other hand, stress the description of supply and demand relationships. Here, the changes in the markets upon climate measures are studied, but this method is not suitable for analyses of specific technologies. Economic analyses of climate changes are relatively new, but the methods are traditional. Some of the main issues discussed in the report are: (1) the connection between climate policies and other environmental policies, (2) the impact on world trade of an international climate agreement, (3) evaluation of the national costs of climate measures, and (4) the impact of technological changes on global emissions of climate gases. 62 refs., 8 figs., 8 tabs.

  3. 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...

  4. 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.

  5. 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.

  6. Global air quality and climate.

    Science.gov (United States)

    Fiore, Arlene M; Naik, Vaishali; Spracklen, Dominick V; Steiner, Allison; Unger, Nadine; Prather, Michael; Bergmann, Dan; Cameron-Smith, Philip J; Cionni, Irene; Collins, William J; Dalsøren, Stig; Eyring, Veronika; Folberth, Gerd A; Ginoux, Paul; Horowitz, Larry W; Josse, Béatrice; Lamarque, Jean-François; MacKenzie, Ian A; Nagashima, Tatsuya; O'Connor, Fiona M; Righi, Mattia; Rumbold, Steven T; Shindell, Drew T; Skeie, Ragnhild B; Sudo, Kengo; Szopa, Sophie; Takemura, Toshihiko; Zeng, Guang

    2012-10-07

    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 (CH(4)), ozone precursors (O(3)), 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 O(3) precursor CH(4) would slow near-term warming by decreasing both CH(4) and tropospheric O(3). Uncertainty remains as to the net climate forcing from anthropogenic nitrogen oxide (NO(x)) emissions, which increase tropospheric O(3) (warming) but also increase aerosols and decrease CH(4) (both cooling). Anthropogenic emissions of carbon monoxide (CO) and non-CH(4) volatile organic compounds (NMVOC) warm by increasing both O(3) and CH(4). 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 O(3) and particulate matter) in many populated regions, including during pollution episodes. Prior Intergovernmental Panel on Climate Change (IPCC) scenarios (SRES) allowed unconstrained growth, whereas

  7. 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

  8. 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

  9. 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

  10. Network class superposition analyses.

    Directory of Open Access Journals (Sweden)

    Carl A B Pearson

    Full Text Available 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.

  11. Impacts of Climate Change on Energy Consumption and Peak Demand in Buildings: A Detailed Regional Approach

    Energy Technology Data Exchange (ETDEWEB)

    Dirks, James A.; Gorrissen, Willy J.; Hathaway, John E.; Skorski, Daniel C.; Scott, Michael J.; Pulsipher, Trenton C.; Huang, Maoyi; Liu, Ying; Rice, Jennie S.

    2015-01-01

    This paper presents the results of numerous commercial and residential building simulations, with the purpose of examining the impact of climate change on peak and annual building energy consumption over the portion of the Eastern Interconnection (EIC) located in the United States. The climate change scenario considered (IPCC A2 scenario as downscaled from the CASCaDE data set) has changes in mean climate characteristics as well as changes in the frequency and duration of intense weather events. This investigation examines building energy demand for three annual periods representative of climate trends in the CASCaDE data set at the beginning, middle, and end of the century--2004, 2052, and 2089. Simulations were performed using the Building ENergy Demand (BEND) model which is a detailed simulation platform built around EnergyPlus. BEND was developed in collaboration with the Platform for Regional Integrated Modeling and Analysis (PRIMA), a modeling framework designed to simulate the complex interactions among climate, energy, water, and land at decision-relevant spatial scales. Over 26,000 building configurations of different types, sizes, vintages, and, characteristics which represent the population of buildings within the EIC, are modeled across the 3 EIC time zones using the future climate from 100 locations within the target region, resulting in nearly 180,000 spatially relevant simulated demand profiles for each of the 3 years. In this study, the building stock characteristics are held constant based on the 2005 building stock in order to isolate and present results that highlight the impact of the climate signal on commercial and residential energy demand. Results of this analysis compare well with other analyses at their finest level of specificity. This approach, however, provides a heretofore unprecedented level of specificity across multiple spectrums including spatial, temporal, and building characteristics. This capability enables the ability to

  12. 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。

  13. 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.

  14. 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.

  15. 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

  16. 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...

  17. 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.

  18. Micromechanical Analyses of Sturzstroms

    Science.gov (United States)

    Imre, Bernd; Laue, Jan; Springman, Sarah M.

    2010-05-01

    have been made observable and reproducible within a physical and a distinct element numerical modelling environment (DEM). As link between field evidence gained from the deposits of natural sturzstroms, the physical model within the ETH Geotechnical Drum Centrifuge (Springman et al., 2001) and the numerical model PFC-3D (Cundall and Strack, 1979; Itasca, 2005), serves a deterministic fractal analytical comminution model (Sammis et al., 1987; Steacy and Sammis, 1991). This approach allowed studying the effects of dynamic fragmentation within sturzstroms at true (macro) scale within the distinct element model, by allowing for a micro-mechanical, distinct particle based, and cyclic description of fragmentation at the same time, without losing significant computational efficiency. Theses experiments indicate rock mass and boundary conditions, which allow an alternating fragmenting and dilating dispersive regime to evolve and to be sustained long enough to replicate the spreading and run out of sturzstroms. The fragmenting spreading model supported here is able to explain the run out of a dry granular flow, beyond the travel distance predicted by a Coulomb frictional sliding model, without resorting to explanations by mechanics that can only be valid for certain, specific of the boundary conditions. The implications derived suggest that a sturzstrom, because of its strong relation to internal fractal fragmentation and other inertial effects, constitutes a landslide category of its own. Its mechanics differ significantly from all other gravity driven mass flows. This proposition does not exclude the possible appearance of frictionites, Toma hills or suspension flows etc., but it considers them as secondary features. The application of a fractal comminution model to describe natural and experimental sturzstrom deposits turned out to be a useful tool for sturzstrom research. Implemented within the DEM, it allows simulating the key features of sturzstrom successfully and

  19. 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...

  20. 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)

  1. 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.

  2. On the reliability of Seasonal Climate Forecasts

    CERN Document Server

    Weisheimer, Antje

    2013-01-01

    Seasonal climate forecasts are being used increasingly across a range of application sectors. A recent UK governmental report asked: How good are seasonal climate forecasts on a scale of 1-5 (where 5 is very good), and how good can we expect them to be in 30 years time? Seasonal climate forecasts are made from ensembles of integrations of numerical models of climate. We argue that goodness should be assessed primarily in terms of the probabilistic reliability of these ensemble-based forecasts and that a 5 should be reserved for systems which are not only reliable overall, but where, in particular, small ensemble spread is a reliable indicator of low ensemble forecast error. We study the reliability of regional temperature and precipitation forecasts of the current operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts, universally regarded as a world leading operational institute producing seasonal climate forecasts. A wide range of goodness rankings, depending on regio...

  3. 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.

  4. 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.

  5. 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

  6. Abrupt climate change: can society cope?

    Science.gov (United States)

    Hulme, Mike

    2003-09-15

    Consideration of abrupt climate change has generally been incorporated neither in analyses of climate-change impacts nor in the design of climate adaptation strategies. Yet the possibility of abrupt climate change triggered by human perturbation of the climate system is used to support the position of both those who urge stronger and earlier mitigative action than is currently being contemplated and those who argue that the unknowns in the Earth system are too large to justify such early action. This paper explores the question of abrupt climate change in terms of its potential implications for society, focusing on the UK and northwest Europe in particular. The nature of abrupt climate change and the different ways in which it has been defined and perceived are examined. Using the example of the collapse of the thermohaline circulation (THC), the suggested implications for society of abrupt climate change are reviewed; previous work has been largely speculative and has generally considered the implications only from economic and ecological perspectives. Some observations about the implications from a more social and behavioural science perspective are made. If abrupt climate change simply implies changes in the occurrence or intensity of extreme weather events, or an accelerated unidirectional change in climate, the design of adaptation to climate change can proceed within the existing paradigm, with appropriate adjustments. Limits to adaptation in some sectors or regions may be reached, and the costs of appropriate adaptive behaviour may be large, but strategy can develop on the basis of a predicted long-term unidirectional change in climate. It would be more challenging, however, if abrupt climate change implied a directional change in climate, as, for example, may well occur in northwest Europe following a collapse of the THC. There are two fundamental problems for society associated with such an outcome: first, the future changes in climate currently being

  7. 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.

  8. 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.

  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. 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

  11. 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

  12. Numerical Methods for Multilattices

    CERN Document Server

    Abdulle, Assyr; Shapeev, Alexander V

    2011-01-01

    Among the efficient numerical methods based on atomistic models, the quasicontinuum (QC) method has attracted growing interest in recent years. The QC method was first developed for crystalline materials with Bravais lattice and was later extended to multilattices (Tadmor et al, 1999). Another existing numerical approach to modeling multilattices is homogenization. In the present paper we review the existing numerical methods for multilattices and propose another concurrent macro-to-micro method in the homogenization framework. We give a unified mathematical formulation of the new and the existing methods and show their equivalence. We then consider extensions of the proposed method to time-dependent problems and to random materials.

  13. 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.

  14. Aerosols, Clouds, and Precipitation as Scale Interactions in the Climate System and Controls on Climate Change

    Science.gov (United States)

    Donner, Leo

    Clouds are major regulators of atmospheric energy flows. Their character depends on atmospheric composition, dynamics, and thermodynamic state. Clouds can assume organized structures whose scales are planetary, while processes important for determining basic properties occur on the scale of microns. The range of processes, scales, and interactions among them has precluded the development of concise theories for the role of clouds in climate, and limitations in modeling clouds in complex climate models remain among the key uncertainties in understanding and projecting climate change. The distribution function of vertical velocities (updraft speeds) in clouds is an important control on climate forcing by clouds and possibly a strong correlate with climate sensitivity. (Climate forcing refers to the change in Earth's energy balance as atmospheric composition changes, in particular, due to human activity. Climate sensitivity is defined here as the equilibrium change in globally averaged annual surface temperature as a result of doubled carbon dioxide.) Vertical velocities are central because they determine the thermodynamic environment governing phase changes of water, with both equilibrium and non-equilibrium phenomena important. The spatial and temporal spectra of relevant vertical velocities includes scales both numerically resolved by climate models and below their resolution limit. The latter implies a requirement to parameterize these smaller scale motions in models. The scale dependence of vertical velocities and emerging observational constraints on their distribution provide new opportunities for representing aerosols, clouds, and precipitation in climate models. Success in doing so could provide important breakthroughs in understanding both climate forcing and sensitivity.

  15. Managing Climate Change Refugia for Climate Adaptation

    Science.gov (United States)

    The concept of refugia has long been studied from theoretical and paleontological 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 ref...

  16. Putting the Nation on a Path for Climate Resilience and Preparedness

    Science.gov (United States)

    Putting current data in a historical context, NOAA publishes the monthly State of the Climate Report that includes analyses of the Nation's recent climate conditions, their unusualness, and their rank within long‐term trends.

  17. 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...

  18. 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

  19. 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...

  20. 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.

  1. From polycrystal to multi-crystal: ''numerical meso-scope'' development for a local analysis in the elasto-viscoplastic field; Du polycristal au multicristal: elaboration d'un mesoscope numerique pour une analyse locale en elastoviscoplasticite

    Energy Technology Data Exchange (ETDEWEB)

    Heraud, St

    2000-07-01

    The knowledge of the local mechanical fields over several adjacent grains is needed for a better understanding of damage initiation and intergranular. failure in metallic polycrystals. This thesis aimed at the derivation of such fields through a 'numerical meso-scope': this simulation tool relies on the finite element analysis of a multi-crystalline pattern embedded in a large matrix whose mechanical behaviour is derived experimentally from classical tests performed on the studied metal. First, we derived macroscopic elastic-viscoplastic constitutive equations from tensile and creep tests on a AIS1316 stainless steel and we inferred from them the general form of similar, but crystallographic equations to be used for the single crystals; the corresponding parameters were determined by fitting the computed overall response of an aggregate made of 1000 grains with the macroscopic experimental one. We then investigated a creep-damaged area of the same steel and we simulated the same grain ensemble in the 'numerical meso-scope' so as to compare the computed normal stress on all grain boundaries with the observed de-bonded boundaries: this showed the most damaged boundaries to sustain the largest normal stress. Another application was concerned with the understanding of the origin of intergranular damage of aged AIS321 stainless steel. A similar approach was adopted with help of the meso-scope: it showed that observations could not be explained by a sole intragranular hardening as it is currently proposed in the literature. Thus the pertinence of the 'numerical meso-scope' concept can now be demonstrated, which opens on a number of new interesting perspectives. (author)

  2. Static Analysis Numerical Algorithms

    Science.gov (United States)

    2016-04-01

    STATIC ANALYSIS OF NUMERICAL ALGORITHMS KESTREL TECHNOLOGY, LLC APRIL 2016 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION...3. DATES COVERED (From - To) NOV 2013 – NOV 2015 4. TITLE AND SUBTITLE STATIC ANALYSIS OF NUMERICAL ALGORITHMS 5a. CONTRACT NUMBER FA8750-14-C... algorithms , linear digital filters and integrating accumulators, modifying existing versions of Honeywell’s HiLiTE model-based development system and

  3. 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

  4. 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.

  5. 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....

  6. 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...

  7. 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...

  8. Climate Change Indicators

    Science.gov (United States)

    Presents information, charts and graphs showing measured climate changes across 40 indicators related to greenhouse gases, weather and climate, oceans, snow and ice, heath and society, and ecosystems.

  9. 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...

  10. Climate impact from peat utilisation in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Uppenberg, S.; Zetterberg, L.; Aahman, M.

    2001-08-01

    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 m{sup 2} 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.

  11. 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

  12. 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.

  13. Effects of climate model interdependency on the uncertainty quantification of extreme rainfall projections

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Madsen, H.; Rosbjerg, Dan;

    Changes in rainfall extremes under climate change conditions are subject to numerous uncertainties. One of the most important uncertainties arises from the inherent uncertainty in climate models. In recent years, many efforts have been made in creating large multi-model ensembles of both Regional...... Climate Models (RCMs) and General Circulation Models (GCMs). These multi-model ensembles provide the information needed to estimate probabilistic climate change projections. Several probabilistic methods have been suggested. One common assumption in most of these methods is that the climate models...... of accounting for the climate model interdependency when estimating the uncertainty of climate change projections....

  14. Indicators for Tracking European Vulnerabilities to the Risks of Infectious Disease Transmission due to Climate Change

    Directory of Open Access Journals (Sweden)

    Jonathan E. Suk

    2014-02-01

    Full Text Available A wide range of infectious diseases may change their geographic range, seasonality and incidence due to climate change, but there is limited research exploring health vulnerabilities to climate change. In order to address this gap, pan-European vulnerability indices were developed for 2035 and 2055, based upon the definition vulnerability = impact/adaptive capacity. Future impacts were projected based upon changes in temperature and precipitation patterns, whilst adaptive capacity was developed from the results of a previous pan-European study. The results were plotted via ArcGISTM to EU regional (NUTS2 levels for 2035 and 2055 and ranked according to quintiles. The models demonstrate regional variations with respect to projected climate-related infectious disease challenges that they will face, and with respect to projected vulnerabilities after accounting for regional adaptive capacities. Regions with higher adaptive capacities, such as in Scandinavia and central Europe, will likely be better able to offset any climate change impacts and are thus generally less vulnerable than areas with lower adaptive capacities. The indices developed here provide public health planners with information to guide prioritisation of activities aimed at strengthening regional preparedness for the health impacts of climate change. There are, however, many limitations and uncertainties when modeling health vulnerabilities. To further advance the field, the importance of variables such as coping capacity and governance should be better accounted for, and there is the need to systematically collect and analyse the interlinkages between the numerous and ever-expanding environmental, socioeconomic, demographic and epidemiologic datasets so as to promote the public health capacity to detect, forecast, and prepare for the health threats due to climate change.

  15. Recent climatological trend of the Saharan heat low and its impact on the West African climate

    Science.gov (United States)

    Lavaysse, Christophe; Flamant, Cyrille; Evan, Amato; Janicot, Serge; Gaetani, Marco

    2016-12-01

    The Saharan heat low (SHL) plays a pivotal role in the West African monsoon system in spring and summer. The recent trend in SHL activity has been analysed using two sets of numerical weather prediction (NWP) model reanalyses and Atmospheric Models Intercomparison Project simulations from 15 climate models performed in the framework of the 5th Coupled Models Intercomparison Project (CMIP5) exercise. A local increase of temperature in the Sahara during the 90s is found in the two sets of NWP models temperature. This increase is stronger within the SHL region than over the surrounding areas. Using different temporal filters (under 25 days, 25-100 days and above 300 days), we show that this is accompanied by a slight but widespread increase of temperature, and a change in the filtered signal under 25 days during the transition period of the 90s. We also show that SHL pulsations occurring at different time scales impact the West Africa climate on a variety of spatial scales, from the regional scale (for the high band pass) to the synoptic scale (for the low band pass signal). Despite a large variability in the temporal trends for 15 climate models from the CMIP5 project, the warming trend in the 90s is observed in the models ensemble mean. Nevertheless, large discrepancies are found between the NWP models reanalyses and the climate model simulations regarding the spatial and temporal evolutions of the SHL as well as its impact on West African climate at the different time scales. These comparisons also reveal that climate models represent the West African monsoon interactions with SHL pulsations quite differently. We provide recommendations to use some of them depending on the time scales of the processes at play (synoptic, seasonal, interannual) and based on key SHL metrics (location, mean intensity, global trend, interaction with the West African monsoon dynamics).

  16. Shifts in climate suitability for wine production as a result of climate change in a temperate climate wine region of Romania

    Science.gov (United States)

    Irimia, Liviu Mihai; Patriche, Cristian Valeriu; Quenol, Hervé; Sfîcă, Lucian; Foss, Chris

    2017-01-01

    Climate change is causing important shifts in the suitability of regions for wine production. Fine scale mapping of these shifts helps us to understand the evolution of vineyard climates, and to find solutions through viticultural adaptation. The aim of this study is to identify and map the structural and spatial shifts that occurred in the climatic suitability for wine production of the Cotnari wine growing region (Romania) between 1961 and 2013. Discontinuities in trends of temperature were identified, and the averages and trends of 13 climatic parameters for the 1961 to 1980 and 1981 to 2013 time periods were analysed. Using the averages of these climatic parameters, climate suitability for wine production was calculated at a resolution of 30 m and mapped for each time period, and the changes analysed. The results indicate shifts in the area's historic climatic profile, due to an increase of heliothermal resources and precipitation constancy. The area's climate suitability for wine production was modified by the loss of climate suitability for white table wines, sparkling wines and wine for distillates; shifts in suitability to higher altitudes by about 67 m, and a 48.6% decrease in the area suitable for quality white wines; and the occurrence of suitable climates for red wines at lower altitudes. The study showed that climate suitability for wine production has a multi-level spatial structure, with classes requiring a cooler climate being located at a higher altitude than those requiring a warmer climate. Climate change has therefore resulted in the shift of climate suitability classes for wine production to higher altitudes.

  17. REDD+ and Climate Smart Agriculture in landscapes

    NARCIS (Netherlands)

    Salvini, G.

    2016-01-01

    Global challenges posed by an increasing food demand and climate change call for innovative mechanisms that consider both agriculture and forests. Agriculture and forests are deeply interconnected in mosaic landscapes, just as multiple pieces of the same puzzle. These pieces are handled by numerous

  18. 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.

  19. Abrupt climate change and extinction events

    Science.gov (United States)

    Crowley, Thomas J.

    1988-01-01

    There is a growing body of theoretical and empirical support for the concept of instabilities in the climate system, and indications that abrupt climate change may in some cases contribute to abrupt extinctions. Theoretical indications of instabilities can be found in a broad spectrum of climate models (energy balance models, a thermohaline model of deep-water circulation, atmospheric general circulation models, and coupled ocean-atmosphere models). Abrupt transitions can be of several types and affect the environment in different ways. There is increasing evidence for abrupt climate change in the geologic record and involves both interglacial-glacial scale transitions and the longer-term evolution of climate over the last 100 million years. Records from the Cenozoic clearly show that the long-term trend is characterized by numerous abrupt steps where the system appears to be rapidly moving to a new equilibrium state. The long-term trend probably is due to changes associated with plate tectonic processes, but the abrupt steps most likely reflect instabilities in the climate system as the slowly changing boundary conditions caused the climate to reach some threshold critical point. A more detailed analysis of abrupt steps comes from high-resolution studies of glacial-interglacial fluctuations in the Pleistocene. Comparison of climate transitions with the extinction record indicates that many climate and biotic transitions coincide. The Cretaceous-Tertiary extinction is not a candidate for an extinction event due to instabilities in the climate system. It is quite possible that more detailed comparisons and analysis will indicate some flaws in the climate instability-extinction hypothesis, but at present it appears to be a viable candidate as an alternate mechanism for causing abrupt environmental changes and extinctions.

  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. 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.

  2. 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.

  3. Double Exposure: Photographing Climate Change

    Science.gov (United States)

    Arnold, D. P.; Wake, C. P.; Romanow, G. B.

    2008-12-01

    Double Exposure, Photographing Climate Change, is a fine-art photography exhibition that examines climate change through the prism of melting glaciers. The photographs are twinned shots of glaciers, taken in the mid-20th century by world-renowned photographer Brad Washburn, and in the past two years by Boston journalist/photographer David Arnold. Arnold flew in Washburn's aerial "footprints", replicating stunning black and white photographs, and documenting one irreversible aspect of climate change. Double Exposure is art with a purpose. It is designed to educate, alarm and inspire its audiences. Its power lies in its beauty and the shocking changes it has captured through a camera lens. The interpretive text, guided by numerous experts in the fields of glaciology, global warming and geology, helps convey the message that climate change has already forced permanent changes on the face of our planet. The traveling exhibit premiered at Boston's Museum of Science in April and is now criss-crossing the nation. The exhibit covers changes in the 15 glaciers that have been photographed as well as related information about global warming's effect on the planet today.

  4. 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...

  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. Efficient numerical integration of neutrino oscillations in matter

    Science.gov (United States)

    Casas, F.; D'Olivo, J. C.; Oteo, J. A.

    2016-12-01

    A special purpose solver, based on the Magnus expansion, well suited for the integration of the linear three neutrino oscillations equations in matter is proposed. The computations are speeded up to two orders of magnitude with respect to a general numerical integrator, a fact that could smooth the way for massive numerical integration concomitant with experimental data analyses. Detailed illustrations about numerical procedure and computer time costs are provided.

  7. Efficient numerical integration of neutrino oscillations in matter

    CERN Document Server

    Casas, Fernando; D'Olivo, Juan Carlos

    2016-01-01

    A special purpose solver, based on the Magnus expansion, well suited for the integration of the linear three neutrino oscillations equations in matter is proposed. The computations are speeded up to two orders of magnitude with respect to a general numerical integrator, a fact that could smooth the way for massive numerical integration concomitant with experimental data analyses. Detailed illustrations about numerical procedure and computer time costs are provided.

  8. 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

  9. 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…

  10. 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…

  11. 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...... tools and implementation techniques are described and performance tests are carried out. The equations that govern the motion of fluids with losses and the corresponding boundary conditions are reduced to a form that is tractable for the Boundary Element Method (BEM) by adopting some hypotheses...... 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...

  12. Integrated climate and hydrology modelling

    DEFF Research Database (Denmark)

    Larsen, Morten Andreas Dahl

    global warming and increased frequency of extreme events. The skill in developing projections of both the present and future climate depends essentially on the ability to numerically simulate the processes of atmospheric circulation, hydrology, energy and ecology. Previous modelling efforts of climate...... and hydrology models to more directly include the interaction between the atmosphere and the land surface. The present PhD study is motivated by an ambition of developing and applying a modelling tool capable of including the interaction and feedback mechanisms between the atmosphere and the land surface...... to the LSM in HIRHAM. A wider range of processes are included at the land surface, subsurface flow is distributed in three dimensions and the temporal and spatial resolution is higher. Secondly, the feedback mechanisms of e.g. soil moisture and recipitation between the two models are included...

  13. Climate Change Impacts on Future Wave Climate around the UK

    Directory of Open Access Journals (Sweden)

    William G. Bennett

    2016-11-01

    Full Text Available Understanding the changes in future storm wave climate is crucial for coastal managers and planners to make informed decisions required for sustainable coastal management and for the renewable energy industry. To investigate potential future changes to storm climate around the UK, global wave model outputs of two time slice experiments were analysed with 1979–2009 representing present conditions and 2075–2100 representing the future climate. Three WaveNet buoy sites around the United Kingdom, which represent diverse site conditions and have long datasets, were chosen for this study. A storm event definition (Dissanayake et al., 2015 was used to separate meteorologically-independent storm events from wave data, which in turn allowed storm wave characteristics to be analysed. Model outputs were validated through a comparison of the modelled storm data with observed storm data for overlapping periods. Although no consistent trends across all future clusters were observed, there were no significant increases in storm wave height, storm count or storm power in the future, at least according to the global wave projection results provided by the chosen model.

  14. 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...

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. A numerical study on a lumped-parameter model and a CFD code coupling for the analysis of the loss of coolant accident in a reactor containment; Etude numerique 0D-multiD pour l'analyse de perte de refrigerant dans une enceinte de confinement d'un reacteur nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Y.J.

    2005-12-15

    In the case of PWR severe accident (Loss of Coolant Accident, LOCA), the inner containment ambient properties such as temperature, pressure and gas species concentrations due to the released steam condensation are the main factors that determine the risk. For this reason, their distributions should be known accurately, but the complexity of the geometry and the computational costs are strong limitations to conduct full three-dimensional numerical simulations. An alternative approach is presented in this thesis, namely, the coupling between a lumped-parameter model and a CFD. The coupling is based on the introduction of a 'heat transfer function' between both models and it is expected that large decreases in the CPU-costs may be achieved. First of all, wall condensation models, such as the Uchida or the Chilton-Colburn models which are implemented in the code CAST3M/TONUS, are investigated. They are examined through steady-state calculations by using the code TONUS-0D, based on lumped parameter models. The temperature and the pressure within the inner containment are compared with those reported in the archival literature. In order to build the 'heat transfer function', natural convection heat transfer is then studied by using the code CAST3M for a partitioned cavity which represents a simplified geometry of the reactor containment. At a first step, two-dimensional natural convection heat transfer without condensation is investigated only. Either the incompressible-Boussinesq fluid flow model or the asymptotic low Mach model are considered for solving the time dependent conservation equations. The SUPG finite element method and the implicit scheme are applied for the numerical discretization. The computed results are qualified by the second-order Richardson extrapolation method which allows obtaining the so-called 'Exact values', i.e. grid size independent values. The computations are also validated through non-partitioned cavity case

  1. 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

  2. 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.

  3. Numerical Estimation in Preschoolers

    Science.gov (United States)

    Berteletti, Ilaria; Lucangeli, Daniela; Piazza, Manuela; Dehaene, Stanislas; Zorzi, Marco

    2010-01-01

    Children's sense of numbers before formal education is thought to rely on an approximate number system based on logarithmically compressed analog magnitudes that increases in resolution throughout childhood. School-age children performing a numerical estimation task have been shown to increasingly rely on a formally appropriate, linear…

  4. 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.

  5. 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...

  6. Numerical methods in control

    Science.gov (United States)

    Mehrmann, Volker; Xu, Hongguo

    2000-11-01

    We study classical control problems like pole assignment, stabilization, linear quadratic control and H[infinity] control from a numerical analysis point of view. We present several examples that show the difficulties with classical approaches and suggest reformulations of the problems in a more general framework. We also discuss some new algorithmic approaches.

  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. Final report on numerical simulation of processes of hot sheet bending in the frame of the project EUREKA-FASP (EU353). v. 3. Pt. 5. Pt. 6. New source representation obtained by comparison with experimental temperature data; Parametric analyses of area heating processes in the sheet hot bending

    Energy Technology Data Exchange (ETDEWEB)

    Carmignani, B.; Toselli, G. [ENEA, Centro Ricerche `E. Clementel`, Bologna (Italy). Dip. Innovazione

    1996-10-01

    This work is the final report of the activity developed in the frame of the European project EUREKA-FASP (EU353) concerning the numerical simulation of the processes of the hot shaping or bending of large sheets, of interest of the ship-buildings, by the use of ABACUS code in its implicit version (ABAQUS/S). The work has been subdivided in 6 parts according to different considered aspects and made choices. Substantially, two different types of sheet heating processes have been considered, that is line heating and area heating processes, while two aims have been pursued; (1) to single out the best strategies in order to simulate the shaping of large sheets in a suitable way corresponding to the experience, adopting thermo-structural computation codes, as ABAQUS; (2) to verify and suggest, in some cases, orientations and indications for the design of an automate machine managed by an expert system (one of the aims of FASP project) for the heating of large sheets, able to provide the required shaping or bending of these sheets.

  9. Exploitation of Parallelism in Climate Models

    Energy Technology Data Exchange (ETDEWEB)

    Baer, F.; Tribbia, J.J.; Williamson, D.L.

    1999-03-01

    The US Department of Energy (DOE), through its CHAMMP initiative, hopes to develop the capability to make meaningful regional climate forecasts on time scales exceeding a decade, such capability to be based on numerical prediction type models. We propose research to contribute to each of the specific items enumerated in the CHAMMP announcement (Notice 91-3); i.e., to consider theoretical limits to prediction of climate and climate change on appropriate time scales, to develop new mathematical techniques to utilize massively parallel processors (MPP), to actually utilize MPPs as a research tool, and to develop improved representations of some processes essential to climate prediction. In particular, our goals are to: (1) Reconfigure the prediction equations such that the time iteration process can be compressed by use of MMP architecture, and to develop appropriate algorithms. (2) Develop local subgrid scale models which can provide time and space dependent parameterization for a state- of-the-art climate model to minimize the scale resolution necessary for a climate model, and to utilize MPP capability to simultaneously integrate those subgrid models and their statistics. (3) Capitalize on the MPP architecture to study the inherent ensemble nature of the climate problem. By careful choice of initial states, many realizations of the climate system can be determined concurrently and more realistic assessments of the climate prediction can be made in a realistic time frame. To explore these initiatives, we will exploit all available computing technology, and in particular MPP machines. We anticipate that significant improvements in modeling of climate on the decadal and longer time scales for regional space scales will result from our efforts.

  10. Climate sensitivity and climate change under strong forcing

    Science.gov (United States)

    Boer, G. J.; Hamilton, K.; Zhu, W.

    2005-06-01

    A version of the National Centre for Atmospheric Research (NCAR) coupled climate model is integrated under current climate conditions and in a series of experiments with climate forcings ranging from modest to very strong. The purpose of the experiments is to investigate the nature and behaviour of the climate feedback/sensitivity of the model, its evolution with time and climate state, the robustness of model parameterizations as forcing levels increase, and the possibility of a “runaway” warming under strong forcing. The model is integrated for 50 years, or to failure, after increasing the solar constant by 2.5, 10, 15, 25, 35, and 45% of its control value. The model successfully completes 50 years of integration for the 2.5, 10, 15, and 25% solar constant increases but fails for increases of 35% and 45%. The effective global climate sensitivity evolves with time and analysis indicates that a new equilibrium will be obtained for the 2.5, 10, and 15% cases but that runaway warming is underway for the 25% increase in solar constant. Feedback processes are analysed both locally and globally in terms of longwave and shortwave, clear-sky/surface, and cloud forcing components. Feedbacks in the system must be negative overall and of sufficient strength to balance the positive forcing if the system is to attain a new equilibrium. Longwave negative feedback processes strengthen in a reasonably linear fashion as temperature increases but shortwave feedback processes do not. In particular, solar cloud feedback becomes less negative and, for the 25% forcing case, eventually becomes positive, resulting in temperatures that “run away”. The conditions under which a runaway climate warming might occur have previously been investigated using simpler models. For sufficiently strong forcing, the greenhouse effect of increasing water vapour in a warmer atmosphere is expected to overwhelm the negative feedback of the longwave cooling to space as temperature increases. This is

  11. 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.

  12. Numerical simulation of axial flow compressors.

    OpenAIRE

    Jesuino Takachi Tomita

    2002-01-01

    This work deals with the numerical simulation of axial flow compressors, from design to performance prediction. The stage performance prediction uses the meanline flow properties. Stage-stacking is used to analyse a multi-stage compressor. A computer program, written in FORTRAN, was developed and is able to design an axial flow compressor given air mass flow, total pressure ratio, overall efficiency and design speed. All geometrical data relevant to the compressor performance prediction is ca...

  13. Beyond climate: disturbance niche shifts in invasive species

    OpenAIRE

    González-Moreno, Pablo; Diez, Jeffrey M.; Richardson, David M.; Vilà, Montserrat

    2015-01-01

    Analysing how species niches shift between native and introduced ranges is a powerful tool for understanding the determinants of species distributions and for anticipating range expansions by invasive species. Most studies only consider the climatic niche, by correlating widely available presence-only data with regional climate. However, habitat characteristics and disturbance also shape species niches, thereby potentially confounding shifts attributed only to differences in climate. Here we ...

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Staff Turnover in Assertive Community Treatment (Act) Teams: The Role of Team Climate.

    Science.gov (United States)

    Zhu, Xi; Wholey, Douglas R; Cain, Cindy; Natafgi, Nabil

    2017-03-01

    Staff turnover in Assertive Community Treatment (ACT) teams can result in interrupted services and diminished support for clients. This paper examines the effect of team climate, defined as team members' shared perceptions of their work environment, on turnover and individual outcomes that mediate the climate-turnover relationship. We focus on two climate dimensions: safety and quality climate and constructive conflict climate. Using survey data collected from 26 ACT teams, our analyses highlight the importance of safety and quality climate in reducing turnover, and job satisfaction as the main mediator linking team climate to turnover. The findings offer practical implications for team management.

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. Mapping the landscape of climate engineering

    Science.gov (United States)

    Oldham, P.; Szerszynski, B.; Stilgoe, J.; Brown, C.; Eacott, B.; Yuille, A.

    2014-01-01

    In the absence of a governance framework for climate engineering technologies such as solar radiation management (SRM), the practices of scientific research and intellectual property acquisition can de facto shape the development of the field. It is therefore important to make visible emerging patterns of research and patenting, which we suggest can effectively be done using bibliometric methods. We explore the challenges in defining the boundary of climate engineering, and set out the research strategy taken in this study. A dataset of 825 scientific publications on climate engineering between 1971 and 2013 was identified, including 193 on SRM; these are analysed in terms of trends, institutions, authors and funders. For our patent dataset, we identified 143 first filings directly or indirectly related to climate engineering technologies—of which 28 were related to SRM technologies—linked to 910 family members. We analyse the main patterns discerned in patent trends, applicants and inventors. We compare our own findings with those of an earlier bibliometric study of climate engineering, and show how our method is consistent with the need for transparency and repeatability, and the need to adjust the method as the field develops. We conclude that bibliometric monitoring techniques can play an important role in the anticipatory governance of climate engineering. PMID:25404683

  5. Multiple Imputation for Network Analyses

    NARCIS (Netherlands)

    Krause, Robert; Huisman, Mark; Steglich, Christian; Snijders, Thomas

    2016-01-01

    Missing data on network ties is a fundamental problem for network analyses. The biases induced by missing edge data, even when missing completely at random (MCAR), are widely acknowledged and problematic for network analyses (Kossinets, 2006; Huisman & Steglich, 2008; Huisman, 2009). Although model-

  6. 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.

  7. The climate crisis calls for a new educational era

    DEFF Research Database (Denmark)

    Mehlsen, Camilla

    2009-01-01

    The International Alliance of Leading Education Institutes is analysing the role that education ought to play in a world struggling with climate change. Professor Jeppe Læssøe talks about the initial findings.......The International Alliance of Leading Education Institutes is analysing the role that education ought to play in a world struggling with climate change. Professor Jeppe Læssøe talks about the initial findings....

  8. 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

  9. 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.

  10. 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.

  11. PUBLIC PRIVATE COLLABORATION ON CLIMATE CHANGE MITIGATION

    DEFF Research Database (Denmark)

    Dirckinck-Holmfeld, Kasper

    ’ activities to combine local business support with the climate and environmental agenda under the concept of green growth • The learning and competences of the municipal officers. The insights from these five analyses are combined into the sixth analysis as an assessment of the competencies needed to assist...

  12. Ecosystem based approaches to climate adaptation

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Jensen, Anne; Termansen, Mette

    This report analyses the prospects and barriers of applying ecosystem based approaches systematically to climate adaptation in urban areas, taking the case of green roofs in Copenhagen Municipality. It looks at planning aspects of green roofs in Copenhagen as well as citizen views and preferences...

  13. Why Interfaces are the Key for Developing Climate Services

    Science.gov (United States)

    Cortekar, Jörg; Bender, Steffen; Groth, Markus

    2015-04-01

    Responding to climate change today involves both mitigation to address the cause and adaptation as a response to already on-going and expected changes. But to what exactly do we have to adapt? And what happens, when environmental, economical or administrative boundary conditions changes? In recent years the concept of climate services has evolved to provide user tailored information to meet individual adaptation needs. According to the Global Framework for Climate Services, climate services involve high-quality data e.g. on temperature, rainfall, wind, etc., as well as maps, risk and vulnerability analyses, assessments, and long-term projections and scenarios. Depending on specific user's needs, these data and information products may be combined with non-meteorological sector-specific data, such as agricultural production, flood risk maps or health trends, and other socio-economic variables to support decision-making of stakeholders who are affected by climate change. This, still non-exhaustive list already indicates that many different scientific disciplines are involved in the development and provision of climate services. Integrating different and equally important scientific approaches to contribute to the solution of one specific problem is challenging. In economics, for instance, many different and promising methods and tools such as cost-benefit-analyses are available which play a key role in providing policy makers and other stakeholders with data and information in order to create a robust decision-making basis for efficiently using scarce budgets. Cost-benefit-analysis is a well-established method in economic theory, its application in the field of climate change adaptation, however, is still new. The bulk of cost and benefit assessments currently pursues a top-down-approach. That is, the required data is generated by downscaling cost and benefit estimations of global impact assessment models to a specific region. In many cases global information are not

  14. The Copernicus Climate Change Service (C3S): Open Access to a Climate Data Store

    Science.gov (United States)

    Thepaut, Jean-Noel; Dee, Dick

    2016-04-01

    In November 2014, The European Centre for Medium-range Weather Forecasts (ECMWF) signed an agreement with the European Commission to deliver two of the Copernicus Earth Observation Programme Services on the Commission's behalf. The ECMWF delivered services - the Copernicus Climate Change Service (C3S) and Atmosphere Monitoring Service (CAMS) - will bring a consistent standard to how we monitor and predict atmospheric conditions and climate change. They will maximise the potential of past, current and future earth observations - ground, ocean, airborne, satellite - and analyse these to monitor and predict atmospheric conditions and in the future, climate change. With the wealth of free and open data that the services provide, they will help business users to assess the impact of their business decisions and make informed choices, delivering a more energy efficient and climate aware economy. These sound investment decisions now will not only stimulate growth in the short term, but reduce the impact of climate change on the economy and society in the future. C3S is in its proof of concept phase and through its Climate Data Store will provide • global and regional climate data reanalyses; • multi-model seasonal forecasts; • customisable visual data to enable examination of wide range of scenarios and model the impact of changes; • access to all the underlying data, including climate data records from various satellite and in-situ observations. In addition, C3S will provide key indicators on climate change drivers (such as carbon dioxide) and impacts (such as reducing glaciers). The aim of these indicators will be to support European adaptation and mitigation policies in a number of economic sectors. At the heart of the Service is the provision of open access to a one stop shop (the Climate Data Store) of climate data and modelling, analysing more than 20 Essential Climate Variables to build a global picture of our past, present and future climate and developing

  15. FUTURE CLIMATE ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    R.M. Forester

    2000-03-14

    This Analysis/Model Report (AMR) 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 (YM), Nevada (Figure l), the site of a potential repository for high-level radioactive waste. The future-climate estimates are based on an analysis of past-climate data from analog meteorological stations, and this AMR 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 infiltration model (USGS 2000) and for the total system performance assessment for the Site Recommendation (TSPA-SR) at YM. 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 method, among many, of establishing upper and lower bounds for future climate estimates. The method used here involves selecting a particular past climate from many past climates, as an analog for future climate. Other studies might develop a different rationale or select other past climates resulting in a different future climate analog.

  16. Modeling the water balance of sloped vineyards under various climate change scenarios

    Directory of Open Access Journals (Sweden)

    Hofmann Marco

    2015-01-01

    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 to 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 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.

  17. Natural Climate Variability and Future Climate Policy

    Science.gov (United States)

    Ricke, K.; Caldeira, K.

    2013-12-01

    Individual beliefs about climate change and willingness-to-pay for its mitigation are influenced by local weather and climate. Large ensemble climate modeling experiments have demonstrated the large role natural variability plays in local weather and climate on a multidecadal timescale. Here we illustrate how if support for global climate policies and subsequent implementation of those policies are determined by citizens' local experiences, natural variability could influence the timeline for implementation of emissions reduction policies by decades. The response of complex social systems to local and regional changes in weather and climate cannot be quantitatively predicted with confidence. Both the form and timing of the societal response can be affected by interactions between social systems and the physical climate system. Here, to illustrate one type of influence decadal natural variability can have on climate policy, we consider a simple example in which the only question is when, if ever, the different parties will support emissions reduction. To analyze the potential effect that unpredictable extreme events may have on the time to reach a global agreement on climate policy, we analyzed the output from a 40-member Community Climate System Model version 3 simulation ensemble to illustrate how local experiences might affect the timing of acceptance of strong climate policy measures. We assume that a nation's decision to take strong actions to abate emissions is contingent upon the local experiences of its citizens and then examine how the timelines for policy action may be influenced by variability in local weather. To illustrate, we assume that a social 'tipping point' is reached at the national level occurs when half of the population of a nation has experienced a sufficiently extreme event. If climate policies are driven by democratic consensus then variability in weather could result in significantly disparate times-to-action. For the top six CO2 emitters

  18. Linking Teleconnections and Iowa's Climate

    Science.gov (United States)

    Rowe, S. T.; Villarini, G.; Lavers, D. A.; Scoccimarro, E.

    2013-12-01

    In recent years Iowa and the U.S. Midwest has experienced both extreme drought and flood periods. With a drought in 2012 bounded by major floods in 2011 and 2013, the rapid progression from one extreme to the next is on the forefront of the public mind. Given that Iowa is a major agricultural state, extreme weather conditions can have severe socioeconomic consequences. In this research we investigate the large-scale climate processes that occurred concurrently and before a range of dry/wet and cold/hot periods to improve process understanding of these events. It is essential to understand the large-scale climate processes, as these can then provide valuable insight toward the development of long-term climate forecasts for Iowa. In this study monthly and seasonal surface temperature and precipitation over 1950-2012 across Iowa are used. Precipitation and surface temperature data are retrieved from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) Climate Group at Oregon State University. The large-scale atmospheric fields are obtained from the National Center for Environmental Prediction (NCEP) / National Center for Atmospheric Research (NCAR) Reanalysis 1 Project. Precipitation is stratified according to wet, normal, and dry conditions, while temperature according to hot, average, and cold periods. Different stratification criteria based on the precipitation and temperature distributions are examined. Mean sea-level pressure and sea-surface temperature composite maps for the northern hemisphere are then produced for the wet/dry conditions, and cold/hot conditions. Further analyses include correlation, anomalies, and assessment of large-scale planetary wave activity, shedding light on the differences and similarities among the opposite weather conditions. The results of this work will highlight regional weather patterns that are related to the climate over Iowa, providing valuable insight into the mechanisms controlling the occurrence of

  19. 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

  20. Organizational Climates: An Essay

    Science.gov (United States)

    Schneider, Benjamin

    1975-01-01

    The purposes of this essay are to (a) present some evidence about the importance of the climate concept as an aid in understanding employee behavior in work organizations and (b) provide a framework for guiding future climate research. (Author)

  1. Doriot Climatic Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — The Doriot Climatic Chambers are two, 60-feet long, 11-feet high, 15-feet wide chambers that are owned and operated by NSRDEC. The Doriot Climatic Chambers are among...

  2. Climate Change and Health

    Science.gov (United States)

    ... sheets Fact files Questions & answers Features Multimedia Contacts Climate change and health Fact sheet Reviewed June 2016 Key ... in improved health, particularly through reduced air pollution. Climate change Over the last 50 years, human activities – particularly ...

  3. Uncertainty Quantification in Climate Modeling and Projection

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Yun; Jackson, Charles; Giorgi, Filippo; Booth, Ben; Duan, Qingyun; Forest, Chris; Higdon, Dave; Hou, Z. Jason; Huerta, Gabriel

    2016-05-01

    The projection of future climate is one of the most complex problems undertaken by the scientific community. Although scientists have been striving to better understand the physical basis of the climate system and to improve climate models, the overall uncertainty in projections of future climate has not been significantly reduced (e.g., from the IPCC AR4 to AR5). With the rapid increase of complexity in Earth system models, reducing uncertainties in climate projections becomes extremely challenging. Since uncertainties always exist in climate models, interpreting the strengths and limitations of future climate projections is key to evaluating risks, and climate change information for use in Vulnerability, Impact, and Adaptation (VIA) studies should be provided with both well-characterized and well-quantified uncertainty. The workshop aimed at providing participants, many of them from developing countries, information on strategies to quantify the uncertainty in climate model projections and assess the reliability of climate change information for decision-making. The program included a mixture of lectures on fundamental concepts in Bayesian inference and sampling, applications, and hands-on computer laboratory exercises employing software packages for Bayesian inference, Markov Chain Monte Carlo methods, and global sensitivity analyses. The lectures covered a range of scientific issues underlying the evaluation of uncertainties in climate projections, such as the effects of uncertain initial and boundary conditions, uncertain physics, and limitations of observational records. Progress in quantitatively estimating uncertainties in hydrologic, land surface, and atmospheric models at both regional and global scales was also reviewed. The application of Uncertainty Quantification (UQ) concepts to coupled climate system models is still in its infancy. The Coupled Model Intercomparison Project (CMIP) multi-model ensemble currently represents the primary data for

  4. Climate bifurcation during the last deglaciation?

    Directory of Open Access Journals (Sweden)

    T. M. Lenton

    2012-07-01

    Full Text Available There were two abrupt warming events during the last deglaciation, at the start of the Bølling-Allerød and at the end of the Younger Dryas, but their underlying dynamics are unclear. Some abrupt climate changes may involve gradual forcing past a bifurcation point, in which a prevailing climate state loses its stability and the climate tips into an alternative state, providing an early warning signal in the form of slowing responses to perturbations, which may be accompanied by increasing variability. Alternatively, short-term stochastic variability in the climate system can trigger abrupt climate changes, without early warning. Previous work has found signals consistent with slowing down during the last deglaciation as a whole, and during the Younger Dryas, but with conflicting results in the run-up to the Bølling-Allerød. Based on this, we hypothesise that a bifurcation point was approached at the end of the Younger Dryas, in which the cold climate state, with weak Atlantic overturning circulation, lost its stability, and the climate tipped irreversibly into a warm interglacial state. To test the bifurcation hypothesis, we analysed two different climate proxies in three Greenland ice cores, from the Last Glacial Maximum to the end of the Younger Dryas. Prior to the Bølling warming, there was a robust increase in climate variability but no consistent slowing down signal, suggesting this abrupt change was probably triggered by a stochastic fluctuation. The transition to the warm Bølling-Allerød state was accompanied by a slowing down in climate dynamics and an increase in climate variability. We suggest that the Bølling warming excited an internal mode of variability in Atlantic meridional overturning circulation strength, causing multi-centennial climate fluctuations. However, the return to the Younger Dryas cold state increased climate stability. We find no consistent evidence for slowing down during the Younger Dryas, or in a longer

  5. Progress in the Study of Nonlinear Atmospheric Dynamics and Predictability of Weather and Climate in China (2007-2011)

    Institute of Scientific and Technical Information of China (English)

    ZHOU Feifan; DING Ruiqiang; FENG Guolin; FU Zuntao; DUAN Wansuo

    2012-01-01

    Recent progress in the study of nonlinear atmospheric dynamics and related predictability of weather and climate in China (2007-2011) are briefly introduced in this article.Major achievements in the study of nonlinear atmospheric dynamics have been classified into two types:(1) progress based on the analysis of solutions of simplified control equations,such as the dynamics of NAO,the optimal precursors for blocking onset,and the behavior of nonlinear waves,and (2) progress based on data analyses,such as the nonlinear analyses of fluctuations and recording-breaking temperature events,the long-range correlation of extreme events,and new methods of detecting abrupt dynamical change.Major achievements in the study of predictability include the following:(1) the application of nonlinear local Lyapunov exponents (NLLE) to weather and climate predictability; (2) the application of condition nonlinear optimal perturbation (CNOP) to the studies of El Ni(n)o-Southern Oscillation (ENSO) predictions,ensemble forecasting,targeted observation,and sensitivity analysis of the ecosystem; and (3) new strategies proposed for predictability studies.The results of these studies have provided greater understanding of the dynamics and nonlinear mechanisms of atmospheric motion,and they represent new ideas for developing numerical models and improving the forecast skill of weather and climate events.

  6. Progress in the study of nonlinear atmospheric dynamics and predictability of weather and climate in China (2007-2011)

    Science.gov (United States)

    Zhou, Feifan; Ding, Ruiqiang; Feng, Guolin; Fu, Zuntao; Duan, Wansuo

    2012-09-01

    Recent progress in the study of nonlinear atmospheric dynamics and related predictability of weather and climate in China (2007-2011) are briefly introduced in this article. Major achievements in the study of nonlinear atmospheric dynamics have been classified into two types: (1) progress based on the analysis of solutions of simplified control equations, such as the dynamics of NAO, the optimal precursors for blocking onset, and the behavior of nonlinear waves, and (2) progress based on data analyses, such as the nonlinear analyses of fluctuations and recording-breaking temperature events, the long-range correlation of extreme events, and new methods of detecting abrupt dynamical change. Major achievements in the study of predictability include the following: (1) the application of nonlinear local Lyapunov exponents (NLLE) to weather and climate predictability; (2) the application of condition nonlinear optimal perturbation (CNOP) to the studies of El Niño-Southern Oscillation (ENSO) predictions, ensemble forecasting, targeted observation, and sensitivity analysis of the ecosystem; and (3) new strategies proposed for predictability studies. The results of these studies have provided greater understanding of the dynamics and nonlinear mechanisms of atmospheric motion, and they represent new ideas for developing numerical models and improving the forecast skill of weather and climate events.

  7. Abrupt change in climate and climate models

    Directory of Open Access Journals (Sweden)

    A. J. Pitman

    2006-01-01

    Full Text Available First, we review the evidence that abrupt climate changes have occurred in the past and then demonstrate that climate models have developing capacity to simulate many of these changes. In particular, the processes by which changes in the ocean circulation drive abrupt changes appear to be captured by climate models to a degree that is encouraging. The evidence that past changes in the ocean have driven abrupt change in terrestrial systems is also convincing, but these processes are only just beginning to be included in climate models. Second, we explore the likelihood that climate models can capture those abrupt changes in climate that may occur in the future due to the enhanced greenhouse effect. We note that existing evidence indicates that a major collapse of the thermohaline circulation seems unlikely in the 21st century, although very recent evidence suggests that a weakening may already be underway. We have confidence that current climate models can capture a weakening, but a collapse in the 21st century of the thermohaline circulation is not projected by climate models. Worrying evidence of instability in terrestrial carbon, from observations and modelling studies, is beginning to accumulate. Current climate models used by the Intergovernmental Panel on Climate Change for the 4th Assessment Report do not include these terrestrial carbon processes. We therefore can not make statements with any confidence regarding these changes. At present, the scale of the terrestrial carbon feedback is believed to be small enough that it does not significantly affect projections of warming during the first half of the 21st century. However, the uncertainties in how biological systems will respond to warming are sufficiently large to undermine confidence in this belief and point us to areas requiring significant additional work.

  8. Abrupt change in climate and climate models

    Directory of Open Access Journals (Sweden)

    A. J. Pitman

    2006-07-01

    Full Text Available First, we review the evidence that abrupt climate changes have occurred in the past and then demonstrate that climate models have developing capacity to simulate many of these changes. In particular, the processes by which changes in the ocean circulation drive abrupt changes appear to be captured by climate models to a degree that is encouraging. The evidence that past changes in the ocean have driven abrupt change in terrestrial systems is also convincing, but these processes are only just beginning to be included in climate models. Second, we explore the likelihood that climate models can capture those abrupt changes in climate that may occur in the future due to the enhanced greenhouse effect. We note that existing evidence indicates that a major collapse of the thermohaline circulate seems unlikely in the 21st century, although very recent evidence suggests that a weakening may already be underway. We have confidence that current climate models can capture a weakening, but a collapse of the thermohaline circulation in the 21st century is not projected by climate models. Worrying evidence of instability in terrestrial carbon, from observations and modelling studies, is beginning to accumulate. Current climate models used by the Intergovernmental Panel on Climate Change for the 4th Assessment Report do not include these terrestrial carbon processes. We therefore can not make statements with any confidence regarding these changes. At present, the scale of the terrestrial carbon feedback is believed to be small enough that it does not significantly affect projections of warming during the first half of the 21st century. However, the uncertainties in how biological systems will respond to warming are sufficiently large to undermine confidence in this belief and point us to areas requiring significant additional work.

  9. Regional climate change mitigation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rowlands, Ian H. [UNEP Collaborating Centre on Energy and Environment, and Univ. of Waterloo (Canada)

    1998-10-01

    The purpose of this paper is to explore some of the key methodological issues that arise from an analysis of regional climate change mitigation options. The rationale for any analysis of regional mitigation activities, emphasising both the theoretical attractiveness and the existing political encouragement and the methodology that has been developed are reviewed. The differences arising from the fact that mitigation analyses have been taken from the level of the national - where the majority of the work has been completed to date - to the level of the international - that is, the `regional` - will be especially highlighted. (EG)

  10. Potential effects of climate change on freshwater ecosystems of the New England/Mid-Atlantic Region

    Science.gov (United States)

    Moore, M.V.; Pace, M.L.; Mather, J.R.; Murdoch, Peter S.; Howarth, R.W.; Folt, C.L.; Chen, C.-Y.; Hemond, Harold F.; Flebbe, P.A.; Driscoll, C.T.

    1997-01-01

    Numerous freshwater ecosystems, dense concentrations of humans along the eastern seaboard, extensive forests and a history of intensive land use distinguish the New England/Mid-Atlantic Region. Human population densities are forecast to increase in portions of the region at the same time that climate is expected to be changing. Consequently, the effects of humans and climatic change are likely to affect freshwater ecosystems within the region interactively. The general climate, at present, is humid continental, and the region receives abundant precipitation. Climatic projections for a 2 ??CO2 atmosphere, however, suggest warmer and drier conditions for much of this region. Annual temperature increases ranging from 3-5??C are projected, with the greatest increases occurring in autumn or winter. According to a water balance model, the projected increase in temperature will result in greater rates of evaporation and evapotranspiration. This could cause a 21 and 31% reduction in annual stream flow in the southern and northern sections of the region, respectively, with greatest reductions occurring in autumn and winter. The amount and duration of snow cover is also projected to decrease across the region, and summer convective thunderstorms are likely to decrease in frequency but increase in intensity. The dual effects of climate change and direct anthropogenic stress will most likely alter hydrological and biogeochemical processes, and, hence, the floral and faunal communities of the region's freshwater ecosystems. For example, the projected increase in evapotranspiration and evaporation could eliminate most bog ecosystems, and increases in water temperature may increase bioaccumulation, and possibly biomagnification, of organic and inorganic contaminants. Not all change may be adverse. For example, a decrease in runoff may reduce the intensity of ongoing estuarine eutrophication, and acidification of aquatic habitats during the spring snowmelt period may be

  11. Gender and Climate Justice

    OpenAIRE

    Ana Agostino; Rosa Lizarde

    2012-01-01

    Ana Agostino and Rosa Lizarde explore the concept of climate justice as a rights approach to climate change. They propose that those in the South who are most affected by environmental changes need to receive justice from those in the North who are most responsible for climate change. They apply a gender lens to climate change, analyzing how women have been specifically hit by the phenomenon and how they are responding.

  12. Olfactometric analyses or odors measurement by sensorial analyses; Analyses olfactometriques ou mesure des odeurs par analyse sensorielle

    Energy Technology Data Exchange (ETDEWEB)

    Gouronnec, A.M. [Institut de Radioprotection et de Surete Nucleaire (IRSN), 92 - Clamart (France)

    2004-06-15

    The olfactometric analyses presented here are applied to industrial odors being able to generate harmful effects for people. The aim of the olfactometric analyses is to quantify odors, to qualify them or to join a pleasant or an unpleasant character to them (hedonism notion). The aim of this work is at first to present the different measurements carried out, the different measurement methods used and the current applications for each of the methods. (O.M.)

  13. 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

  14. The influence of negative climate changes on physical development of urban and rural areas in Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Rahman NURKOVIĆ

    2014-11-01

    Full Text Available The influence of negative climate changes on physical development of urban and rural areas of Bosnia and Herzegovina has been analysed in the paper. So, economy and society in urban and rural areas of Bosnia and Herzegovina are susceptible to environmental consequences of climate changes. In practice, this means that poorer countries in development of economic activities will suffer most due to climate changes, while some developed countries can be in a position to use new commercial possibilities. Presently, there is a significant scientific consensus that human activity affected the increase of atmospheric concentration of greenhouse gases, respectively the carbon dioxide, methane, nitrous oxide, ozone and chlorofluorocarbon, as a result of global changes of climate that will probably change dramatically during the next centuries in Bosnia and Herzegovina. More and more intensive industrialisation and urbanisation, as well as tourism, a growing phenomenon of the 21st century, have numerous negative direct, indirect and multiplicative effects on flora and fauna habitats of Bosnia and Herzegovina. For all mentioned above, this paper tries to indicate to a need for more significant investing into tourism development, which is presently at a very low level of development in Bosnia and Herzegovina. In the past ten years a dynamical development of tertiary activities in urban and rural areas has been distinguished; among which shopping centres take a significant position. 

  15. Direct and indirect effects of climate change on amphibian populations

    Science.gov (United States)

    Blaustein, Andrew R.; Walls, Susan C.; Bancroft, Betsy A.; Lawler, Joshua J.; Searle, Catherine L.; Gervasi, Stephanie S.

    2010-01-01

    As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth, reproduction and dispersal capabilities. Moreover, climate change can alter amphibian habitats including vegetation, soil, and hydrology. Climate change can influence food availability, predator-prey relationships and competitive interactions which can alter community structure. Climate change can also alter pathogen-host dynamics and greatly influence how diseases are manifested. Changes in climate can interact with other stressors such as UV-B radiation and contaminants. The interactions among all these factors are complex and are probably driving some amphibian population declines and extinctions.

  16. Climate models and scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Fortelius, C.; Holopainen, E.; Kaurola, J.; Ruosteenoja, K.; Raeisaenen, J. [Helsinki Univ. (Finland). Dept. of Meteorology

    1996-12-31

    In recent years the modelling of interannual climate variability has been studied, the atmospheric energy and water cycles, and climate simulations with the ECHAM3 model. In addition, the climate simulations of several models have been compared with special emphasis in the area of northern Europe

  17. Regionalizing global climate models

    NARCIS (Netherlands)

    Pitman, A.J.; Arneth, A.; Ganzeveld, L.N.

    2012-01-01

    Global climate models simulate the Earth's climate impressively at scales of continents and greater. At these scales, large-scale dynamics and physics largely define the climate. At spatial scales relevant to policy makers, and to impacts and adaptation, many other processes may affect regional and

  18. Simulating Global Climate Summits

    Science.gov (United States)

    Vesperman, Dean P.; Haste, Turtle; Alrivy, Stéphane

    2014-01-01

    One of the most persistent and controversial issues facing the global community is climate change. With the creation of the UN Framework Convention on Climate Change (UNFCCC) in 1992 and the Kyoto Protocol (1997), the global community established some common ground on how to address this issue. However, the last several climate summits have failed…

  19. Climate Observations from Space

    Science.gov (United States)

    Briggs, Stephen

    2016-07-01

    The latest Global Climate Observing System (GCOS) Status Report on global climate observations, delivered to the UNFCCC COP21 in November 2016, showed how satellite data are critical for observations relating to climate. Of the 50 Essential Climate Variables (ECVs) identified by GCOS as necessary for understanding climate change, about half are derived only from satellite data while half of the remainder have a significant input from satellites. Hence data from Earth observing satellite systems are now a fundamental requirement for understanding the climate system and for managing the consequences of climate change. Following the Paris Agreement of COP21 this need is only greater. Not only will satellites have to continue to provide data for modelling and predicting climate change but also for a much wider range of actions relating to climate. These include better information on loss and damage, resilience, improved adaptation to change, and on mitigation including information on greenhouse gas emissions. In addition there is an emerging need for indicators of the risks associated with future climate change which need to be better quantified, allowing policy makers both to understand what decisions need to be taken, and to see the consequences of their actions. The presentation will set out some of the ways in which satellite data are important in all aspects of understanding, managing and predicting climate change and how they may be used to support future decisions by those responsible for policy related to managing climate change and its consequences.

  20. Climate Change Law

    NARCIS (Netherlands)

    Farber, D.A.; Peeters, Marjan

    2016-01-01

    This book brings together over seventy fifty authors for a comprehensive examination of the emerging global regime of climate change law. Despite the relative youth of climate change law, we can already begin to see the outlines of legal regimes addressing climate change mitigation and adaptation (a

  1. 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

  2. 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.

  3. Philosophy of climate science part I: observing climate change

    OpenAIRE

    Frigg, Roman; Thompson, Erica; Werndl, Charlotte

    2015-01-01

    This is the first of three parts of an introduction to the philosophy of climate science. In this first part about observing climate change, the topics of definitions of climate and climate change, data sets and data models, detection of climate change, and attribution of climate change will be discussed.

  4. Sand dune patterns on Titan controlled by long-term climate cycles

    Science.gov (United States)

    Ewing, Ryan C.; Hayes, Alex G.; Lucas, Antoine

    2015-01-01

    Linear sand dunes cover the equatorial latitudes of Saturn's moon Titan and are shaped by global wind patterns. These dunes are thought to reflect present-day diurnal, tidal and seasonal winds, but climate models have failed to reproduce observed dune morphologies with these wind patterns. Dunes diagnostic of a specific wind or formative timescale have remained elusive. Here we analyse radar imagery from NASA's Cassini spacecraft and identify barchan, star and reoriented dunes in sediment-limited regions of Titan's equatorial dune fields that diverge by 23° on average from the orientation of linear dunes. These morphologies imply shifts in wind direction and sediment availability. Using a numerical model, we estimate that the observed reorientation of dune crests to a change in wind direction would have taken around 3,000 Saturn years (1 Saturn year ~ 29.4 Earth years) or longer--a timescale that exceeds diurnal, seasonal or tidal cycles. We propose that shifts in winds and sediment availability are the product of long-term climate cycles associated with variations in Saturn's orbit. Orbitally controlled landscape evolution--also proposed to explain the distribution of Titan's polar lakes--implies a dune-forming climate on equatorial Titan that is analogous to Earth.

  5. Climate agreements under limited participation, asymmetric information and market imperfections

    Energy Technology Data Exchange (ETDEWEB)

    Hagem, Cathrine

    1996-12-31

    This thesis relates to climate agreements and cost efficiency by analysing the formation of a system of quota leading to distributed discharge of emissions between countries. Main fields concerned are the greenhouse effect, the political process, efficient and cost-effective climate agreements, and climate agreements under limited participation, asymmetric information and market imperfections covering fields like limited participation in climate agreements, limited participation and indirect impact on non-participating countries` emissions, limited participation and direct impact on non-participating countries` emissions under asymmetric information, and non-competitive market for tradeable quotas. 166 refs., 7 tabs.

  6. 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...... studies of the consistency of marine ecological observations with expectations under climate change. This yielded a metadatabase of 1,735 marine biological responses for which either regional or global climate change was considered as a driver. Included were instances of marine taxa responding as expected...

  7. Climate-conscious architecture. Design and wind testing method for climates in change

    Energy Technology Data Exchange (ETDEWEB)

    Kuismanen, K.

    2008-07-01

    The main objective of this research was to develop practical tools with which it is possible to improve the environment, micro-climate and energy economy of buildings and plans in different climate zones, and take the climate change into account. The parts of the study are: State of art study into existing know-how about climate and planning. Study of the effects of climate change on the built environment. Development of simple micro-climate, nature and built environment analysis methods. Defining the criteria of an acceptable micro-climatic environment. Development of the wind test blower. Presenting ways to interpret test results and draw conclusions. Development of planning and design guidelines for different climate zones. An important part of the research is the development of the CASE wind test instrument, different wind simulation techniques, and the methods of observing the results. Bioclimatic planning and architectural design guidelines for different climate zones are produced. The analyse tools developed give a qualitative overall view, which can be deepened towards a quantitative analyse with wind testing measurements and roughness calculations. No mechanical rules are suggested, but complementary viewpoints and practices introduced to a normal planning process as well as improvement of consultative knowledge. The 'method' is that there is no strict mechanical method, but a deeper understanding of bioclimatic matters. Climate-conscious planning with the developed CASE method, make it possible to design a better micro-climate for new or old built-up areas. Winds can be used in to ventilate exhaust fumes and other pollutants, which improves the quality of air and the healthiness of the urban environment. The analyses and scale-model tests make it possible to shield cold windy areas and to diminish the cooling effect of wind on facades. According to studies in Scandinavian countries this will bring energy savings of 5-15 per cent. The method can

  8. 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.

  9. Assessing Climate Change Induced Turnover in Bird Communities Using Climatically Analogous Regions

    Directory of Open Access Journals (Sweden)

    Janine Sybertz

    2015-02-01

    Full Text Available It is crucial to define and quantify possible impacts of climate change on wildlife in order to be able to pre-adapt management strategies for nature conservation. Thus, it is necessary to assess which species might be affected by climatic changes, especially at the regional scale. We present a novel approach to estimate possible climate change induced turnovers in bird communities and apply this method to Lüneburg Heath, a region in northern Germany. By comparing species pools of future climatically analogous regions situated in France with the Lüneburg Heath species pool, we detected possible trends for alterations within the regional bird community in the course of climate change. These analyses showed that the majority of bird species in Lüneburg Heath will probably be able to tolerate the projected future climate conditions, but that bird species richness, in general, may decline. Species that might leave the community were often significantly associated with inland wetland habitats, but the proportion of inland wetlands within the regions had a significant influence on the magnitude of this effect. Our results suggest that conservation efforts in wetlands have to be strengthened in light of climate change because many species are, in principle, able to tolerate future climate conditions if sufficient habitat is available.

  10. Arctic Climate Systems Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ivey, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Backus, George A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Peterson, Kara J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); van Bloemen Waanders, Bart G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swiler, Laura Painton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Desilets, Darin Maurice [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reinert, Rhonda Karen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    This study began with a challenge from program area managers at Sandia National Laboratories to technical staff in the energy, climate, and infrastructure security areas: apply a systems-level perspective to existing science and technology program areas in order to determine technology gaps, identify new technical capabilities at Sandia that could be applied to these areas, and identify opportunities for innovation. The Arctic was selected as one of these areas for systems level analyses, and this report documents the results. In this study, an emphasis was placed on the arctic atmosphere since Sandia has been active in atmospheric research in the Arctic since 1997. This study begins with a discussion of the challenges and benefits of analyzing the Arctic as a system. It goes on to discuss current and future needs of the defense, scientific, energy, and intelligence communities for more comprehensive data products related to the Arctic; assess the current state of atmospheric measurement resources available for the Arctic; and explain how the capabilities at Sandia National Laboratories can be used to address the identified technological, data, and modeling needs of the defense, scientific, energy, and intelligence communities for Arctic support.

  11. 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....../NCAR reanalysis geostrophic wind data (approximately 200 km resolution) are represented in typically around 150 classes, each with a frequency of occurrence. The mean wind-speed and direction in each class is used as input data to force the mesoscale model, which downscales the wind to a 5 km resolution while...

  12. Climate forcings and climate sensitivities diagnosed from atmospheric global circulation models

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Bruce T. [Boston University, Department of Geography and Environment, Boston, MA (United States); Knight, Jeff R.; Ringer, Mark A. [Met Office Hadley Centre, Exeter (United Kingdom); Deser, Clara; Phillips, Adam S. [National Center for Atmospheric Research, Boulder, CO (United States); Yoon, Jin-Ho [University of Maryland, Cooperative Institute for Climate and Satellites, Earth System Science Interdisciplinary Center, College Park, MD (United States); Cherchi, Annalisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici, and Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy)

    2010-12-15

    Understanding the historical and future response of the global climate system to anthropogenic emissions of radiatively active atmospheric constituents has become a timely and compelling concern. At present, however, there are uncertainties in: the total radiative forcing associated with changes in the chemical composition of the atmosphere; the effective forcing applied to the climate system resulting from a (temporary) reduction via ocean-heat uptake; and the strength of the climate feedbacks that subsequently modify this forcing. Here a set of analyses derived from atmospheric general circulation model simulations are used to estimate the effective and total radiative forcing of the observed climate system due to anthropogenic emissions over the last 50 years of the twentieth century. They are also used to estimate the sensitivity of the observed climate system to these emissions, as well as the expected change in global surface temperatures once the climate system returns to radiative equilibrium. Results indicate that estimates of the effective radiative forcing and total radiative forcing associated with historical anthropogenic emissions differ across models. In addition estimates of the historical sensitivity of the climate to these emissions differ across models. However, results suggest that the variations in climate sensitivity and total climate forcing are not independent, and that the two vary inversely with respect to one another. As such, expected equilibrium temperature changes, which are given by the product of the total radiative forcing and the climate sensitivity, are relatively constant between models, particularly in comparison to results in which the total radiative forcing is assumed constant. Implications of these results for projected future climate forcings and subsequent responses are also discussed. (orig.)

  13. Addressing Climate Crisis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ A series of extreme global weather events,like floods in Pakistan and droughts in Russia,should serve as a call to the world to take action against climate change.But worries have been mounting since global climate talks stalled,partly due to rifts between developed and developing countries.What efforts should be made to force progress in the negotiating process? What role has China played in combating climate change? Su Wei,China's chief climate negotiator and Director-General of the Climate Change Department of the National Development and Reform Commission(NDRC),sat down with Beijing Review reporter Hu Yue to answer these questions and more.

  14. Assessment of coastal vulnerability to climate change hazards at the regional scale: the case study of the North Adriatic Sea

    Directory of Open Access Journals (Sweden)

    S. Torresan

    2012-07-01

    Full Text Available Sea level rise, changes in storms and wave climate as a consequence of global climate change are expected to increase the size and magnitude of flooded and eroding coastal areas, thus having profound impacts on coastal communities and ecosystems. River deltas, beaches, estuaries and lagoons are considered particularly vulnerable to the adverse effects of climate change, which should be studied at the regional/local scale. This paper presents a regional vulnerability assessment (RVA methodology developed to analyse site-specific spatial information on coastal vulnerability to the envisaged effects of global climate change, and assist coastal communities in operational coastal management and conservation. The main aim of the RVA is to identify key vulnerable receptors (i.e. natural and human ecosystems in the considered region and localize vulnerable hot spot areas, which could be considered as homogeneous geographic sites for the definition of adaptation strategies. The application of the RVA methodology is based on a heterogeneous subset of bio-geophysical and socio-economic vulnerability indicators (e.g. coastal topography, geomorphology, presence and distribution of vegetation cover, location of artificial protection, which are a measure of the potential harm from a range of climate-related impacts (e.g. sea level rise inundation, storm surge flooding, coastal erosion. Based on a system of numerical weights and scores, the RVA provides relative vulnerability maps that allow to prioritize more vulnerable areas and targets of different climate-related impacts in the examined region and to support the identification of suitable areas for human settlements, infrastructures and economic activities, providing a basis for coastal zoning and land use planning. The implementation, performance and results of the methodology for the coastal area of the North Adriatic Sea (Italy are fully described in the paper.

  15. Changing Climates @ Colorado State: 100 (Multidisciplinary) Views of Climate Change

    Science.gov (United States)

    Campbell, S.; Calderazzo, J.; Changing Climates, Cmmap Education; Diversity Team

    2011-12-01

    We would like to talk about a multidisciplinary education and outreach program we co-direct at Colorado State University, with support from an NSF-funded STC, CMMAP, the Center for Multiscale Modeling of Atmospheric Processes. We are working to raise public literacy about climate change by providing information that is high quality, up to date, thoroughly multidisciplinary, and easy for non-specialists to understand. Our primary audiences are college-level students, their teachers, and the general public. Our motto is Climate Change is Everybody's Business. To encourage and help our faculty infuse climate-change content into their courses, we have organized some 115 talks given by as many different speakers-speakers drawn from 28 academic departments, all 8 colleges at CSU, and numerous other entities from campus, the community, and farther afield. We began with a faculty-teaching-faculty series and then broadened our attentions to the whole campus and surrounding community. Some talks have been for narrowly focused audiences such as extension agents who work on energy, but most are for more eclectic groups of students, staff, faculty, and citizens. We count heads at most events, and our current total is roughly 6,000. We have created a website (http://changingclimates.colostate.edu) that includes videotapes of many of these talks, short videos we have created, and annotated sources that we judge to be accurate, interesting, clearly written, and aimed at non-specialists, including books, articles and essays, websites, and a few items specifically for college teachers (such as syllabi). Pages of the website focus on such topics as how the climate works / how it changes; what's happening / what might happen; natural ecosystems; agriculture; impacts on people; responses from ethics, art, literature; communication; daily life; policy; energy; and-pulling all the pieces together-the big picture. We have begun working on a new series of very short videos that can be

  16. Financing climate change adaptation.

    Science.gov (United States)

    Bouwer, Laurens M; Aerts, Jeroen C J H

    2006-03-01

    This paper examines the topic of financing adaptation in future climate change policies. A major question is whether adaptation in developing countries should be financed under the 1992 United Nations Framework Convention on Climate Change (UNFCCC), or whether funding should come from other sources. We present an overview of financial resources and propose the employment of a two-track approach: one track that attempts to secure climate change adaptation funding under the UNFCCC; and a second track that improves mainstreaming of climate risk management in development efforts. Developed countries would need to demonstrate much greater commitment to the funding of adaptation measures if the UNFCCC were to cover a substantial part of the costs. The mainstreaming of climate change adaptation could follow a risk management path, particularly in relation to disaster risk reduction. 'Climate-proofing' of development projects that currently do not consider climate and weather risks could improve their sustainability.

  17. Cosmic Rays and Climate

    CERN Document Server

    Kirkby, Jasper

    2007-01-01

    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 correlations between climate and the sunspot cycle that had persisted for only a few decades. Over the last few years, however, diverse reconstructions of past climate change have revealed clear associations with cosmic ray variations recorded in cosmogenic isotope archives, providing persuasive evidence for solar or cosmic ray forcing of the climate. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Although this remains a mystery, observations suggest that cloud cover may be influenced by cosmic rays, which are modulated by the solar wind and, on longer time scales, by the geomagnetic fiel...

  18. What Is Climate?

    Science.gov (United States)

    Lovejoy, S.

    2013-01-01

    Most people have an intuitive understanding of the weather as referring to the state of the atmosphere at a given time and place and of the climate as a kind of average weather. A popular expression of this dichotomy is "the climate is what you expect, the weather is what you get" (Heinlein [1973, p. 352], although often attributed to Mark Twain). Implicit in this belief is the notion of climate as a kind of constant natural state to which the weather would converge if it were averaged over a long enough period. A corollary is that climate change is a consequence of "climate forcings," which are external to the natural climate system and which tend to prevent averages from converging to their true values. In this framework, past climate change may be attributed to orbital changes, variations in solar output, volcanic eruptions, etc. For the recent period, anthropogenic forcings can be added.

  19. Climate Change in Prehistory

    Science.gov (United States)

    Burroughs, William James

    2005-06-01

    How did humankind deal with the extreme challenges of the last Ice Age? How have the relatively benign post-Ice Age conditions affected the evolution and spread of humanity across the globe? By setting our genetic history in the context of climate change during prehistory, the origin of many features of our modern world are identified and presented in this illuminating book. It reviews the aspects of our physiology and intellectual development that have been influenced by climatic factors, and how features of our lives - diet, language and the domestication of animals - are also the product of the climate in which we evolved. In short: climate change in prehistory has in many ways made us what we are today. Climate Change in Prehistory weaves together studies of the climate with anthropological, archaeological and historical studies, and will fascinate all those interested in the effects of climate on human development and history.

  20. Data assimilation experiments with MPIESM climate model

    Directory of Open Access Journals (Sweden)

    Belyaev Konstantin

    2016-01-01

    Full Text Available Further development of data assimilation technique and its application in numerical experiments with state-of-the art Max Plank Institute Earth System model have been carried out. In particularly, the stability problem of assimilation is posed and discussed In the experiments the sea surface height data from archive Archiving, Validating and Interpolating Satellite Ocean have been used. All computations have been realized on cluster system of German Climate Computing Center. The results of numerical experiments with and without assimilation were recorded and analyzed. A special attention has been focused on the Arctic zone. It is shown that there is a good coincidence of model tendencies and independent data.

  1. Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project

    CERN Document Server

    Aylott, Benjamin; Boggs, William D; Boyle, Michael; Brady, Patrick R; Brown, Duncan A; Brügmann, Bernd; Buchman, Luisa T; Buonanno, Alessandra; Cadonati, Laura; Camp, Jordan; Campanelli, Manuela; Centrella, Joan; Chatterji, Shourov; Christensen, Nelson; Chu, Tony; Diener, Peter; Dorband, Nils; Etienne, Zachariah B; Faber, Joshua; Fairhurst, Stephen; Farr, Benjamin; Fischetti, Sebastian; Guidi, Gianluca; Goggin, Lisa M; Hannam, Mark; Herrmann, Frank; Hinder, Ian; Husa, Sascha; Kalogera, Vicky; Keppel, Drew; Kidder, Lawrence E; Kelly, Bernard J; Krishnan, Badri; Laguna, Pablo; Lousto, Carlos O; Mandel, Ilya; Marronetti, Pedro; Matzner, Richard; McWilliams, Sean T; Matthews, Keith D; Mercer, R Adam; Mohapatra, Satyanarayan R P; Mroué, Abdul H; Nakano, Hiroyuki; Ochsner, Evan; Pan, Yi; Pekowsky, Larne; Pfeiffer, Harald P; Pollney, Denis; Pretorius, Frans; Raymond, Vivien; Reisswig, Christian; Rezzolla, Luciano; Rinne, Oliver; Robinson, Craig; Röver, Christian; Santamaría, Lucía; Sathyaprakash, Bangalore; Scheel, Mark A; Schnetter, Erik; Seiler, Jennifer; Shapiro, Stuart L; Shoemaker, Deirdre; Sperhake, Ulrich; Stroeer, Alexander; Sturani, Riccardo; Tichy, Wolfgang; Liu, Yuk Tung; van der Sluys, Marc; van Meter, James R; Vaulin, Ruslan; Vecchio, Alberto; Veitch, John; Viceré, Andrea; Whelan, John T; Zlochower, Yosef

    2009-01-01

    The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search algorithms using numerically generated waveforms and to foster closer collaboration between the numerical relativity and data analysis communities. We describe the results of the first NINJA analysis which focused on gravitational waveforms from binary black hole coalescence. Ten numerical relativity groups contributed numerical data which were used to generate a set of gravitational-wave signals. These signals were injected into a simulated data set, designed to mimic the response of the Initial LIGO and Virgo gravitational-wave detectors. Nine groups analysed this data using search and parameter-estimation pipelines. Matched filter algorithms, un-modelled-burst searches and Bayesian parameter-estimation and model-selection algorithms were applied to the da...

  2. Is journalism failing on climate?

    Science.gov (United States)

    Rahmstorf, Stefan

    2012-12-01

    science journalists. Perhaps this can be most clearly seen from the end result: does the public have a realistic understanding of climate science? Data from the world's prime science nation, the US, suggest not. To give just one striking example, a representative poll conducted by Yale and George Mason Universities (Leiserowitz et al 2011) in 2011 asked the US public what percentage of climate scientists think that global warming is happening. The true answer is a number well above 95%, as surveys of climate scientists or the scientific literature show (Anderegg et al 2010, Doran and Kendall Zimmerman 2009, Oreskes 2004), fully consistent with my own direct experience of working in the climate science community over the past twenty years. But only a small minority (13%) of the survey respondents picked the correct category (81-100%). The largest group of respondents (24%) chose the category 41-60%, i.e. they erroneously thought there are two roughly equal camps in climate science—and this despite the question not even being about the anthropogenic contribution to global warming, but only about the measured fact that global climate is warming! That shows that the general public, at least in the US, has no idea of the very broad consensus that exists in the scientific community about fundamental aspects of climate change. How can such a vast misconception of what is controversial and what is well-established in climate science come about? Important evidence is provided by the analyses of media articles on climate change in six countries just published by James Painter, a BBC journalist for many years, and Teresa Ashe from the University of London (Painter and Ashe 2012). Painter and Ashe analysed climate articles in quality newspapers in the USA, Brazil, China, France, India and the UK over two periods in 2007 and 2009/2010. They find that the voices of 'climate sceptics' are particularly present in the US and the UK, namely in one third and one fifth of the examined

  3. Mitogenomic analyses from ancient DNA

    DEFF Research Database (Denmark)

    Paijmans, Johanna L.A.; Gilbert, M Thomas P; Hofreiter, Michael

    2013-01-01

    analyses (whether using modern or ancient DNA) were largely restricted to the analysis of short fragments of the mitochondrial genome. However, due to many technological advances during the past decade, a growing number of studies have explored the power of complete mitochondrial genome sequences...... (mitogenomes). Such studies were initially limited to analyses of extant organisms, but developments in both DNA sequencing technologies and general methodological aspects related to working with degraded DNA have resulted in complete mitogenomes becoming increasingly popular for ancient DNA studies as well....... To date, at least 124 partially or fully assembled mitogenomes from more than 20 species have been obtained, and, given the rapid progress in sequencing technology, this number is likely to dramatically increase in the future. The increased information content offered by analysing full mitogenomes has...

  4. Mathematical and numerical foundations of turbulence models and applications

    CERN Document Server

    Chacón Rebollo, Tomás

    2014-01-01

    With applications to climate, technology, and industry, the modeling and numerical simulation of turbulent flows are rich with history and modern relevance. The complexity of the problems that arise in the study of turbulence requires tools from various scientific disciplines, including mathematics, physics, engineering, and computer science. Authored by two experts in the area with a long history of collaboration, this monograph provides a current, detailed look at several turbulence models from both the theoretical and numerical perspectives. The k-epsilon, large-eddy simulation, and other models are rigorously derived and their performance is analyzed using benchmark simulations for real-world turbulent flows. Mathematical and Numerical Foundations of Turbulence Models and Applications is an ideal reference for students in applied mathematics and engineering, as well as researchers in mathematical and numerical fluid dynamics. It is also a valuable resource for advanced graduate students in fluid dynamics,...

  5. Incorporating climate change projections into riparian restoration planning and design

    Science.gov (United States)

    Perry, Laura G.; Lindsay V. Reynolds,; Beechie, Timothy J.; Collins, Mathias J.; Shafroth, Patrick B.

    2015-01-01

    Climate change and associated changes in streamflow may alter riparian habitats substantially in coming decades. Riparian restoration provides opportunities to respond proactively to projected climate change effects, increase riparian ecosystem resilience to climate change, and simultaneously address effects of both climate change and other human disturbances. However, climate change may alter which restoration methods are most effective and which restoration goals can be achieved. Incorporating climate change into riparian restoration planning and design is critical to long-term restoration of desired community composition and ecosystem services. In this review, we discuss and provide examples of how climate change might be incorporated into restoration planning at the key stages of assessing the project context, establishing restoration goals and design criteria, evaluating design alternatives, and monitoring restoration outcomes. Restoration planners have access to numerous tools to predict future climate, streamflow, and riparian ecology at restoration sites. Planners can use those predictions to assess which species or ecosystem services will be most vulnerable under future conditions, and which sites will be most suitable for restoration. To accommodate future climate and streamflow change, planners may need to adjust methods for planting, invasive species control, channel and floodplain reconstruction, and water management. Given the considerable uncertainty in future climate and streamflow projections, riparian ecological responses, and effects on restoration outcomes, planners will need to consider multiple potential future scenarios, implement a variety of restoration methods, design projects with flexibility to adjust to future conditions, and plan to respond adaptively to unexpected change.

  6. 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......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 validated with respect to timing, location and intensity of extreme events. The main objective of the RiskChange project (www.riskchange.dhigroup.com) is to establish a consistent scientifically‐based framework for risk‐based design using state‐of‐the‐art knowledge of future changes in climate extreme...... statistics. Very high resolution is required in impact models that are employed to address particular societal needs and risks in terms of adaptation to future climate challenges, (e.g. future storm surge protection of coastlines and low‐level lands or drainage systems in urban areas). The purpose...

  7. Computing the Alexander Polynomial Numerically

    DEFF Research Database (Denmark)

    Hansen, Mikael Sonne

    2006-01-01

    Explains how to construct the Alexander Matrix and how this can be used to compute the Alexander polynomial numerically.......Explains how to construct the Alexander Matrix and how this can be used to compute the Alexander polynomial numerically....

  8. Numerical Relativity Beyond Astrophysics

    CERN Document Server

    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 holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.

  9. Numerical relativity beyond astrophysics

    Science.gov (United States)

    Garfinkle, David

    2017-01-01

    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 holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.

  10. Learning numerical progressions.

    Science.gov (United States)

    Vitz, P C; Hazan, D N

    1974-01-01

    Learning of simple numerical progressions and compound progressions formed by combining two or three simple progressions is investigated. In two experiments, time to solution was greater for compound vs simple progressions; greater the higher the progression's solution level; and greater if the progression consisted of large vs small numbers. A set of strategies is proposed to account for progression learning based on the assumption S computes differences between integers, differences between differences, etc., in a hierarchical fashion. Two measures of progression difficulty, each a summary of the strategies, are proposed; C1 is a count of the number of differences needed to solve a progression; C2 is the same count with higher level differences given more weight. The measures accurately predict in both experiments the mean time to solve 16 different progressions with C2 being somewhat superior. The measures also predict the learning difficulty of 10 other progressions reported by Bjork (1968).

  11. Climate change impacts on US agriculture and forestry: benefits of global climate stabilization

    Science.gov (United States)

    Beach, Robert H.; Cai, Yongxia; Thomson, Allison; Zhang, Xuesong; Jones, Russell; McCarl, Bruce A.; Crimmins, Allison; Martinich, Jeremy; Cole, Jefferson; Ohrel, Sara; DeAngelo, Benjamin; McFarland, James; Strzepek, Kenneth; Boehlert, Brent

    2015-09-01

    Increasing atmospheric carbon dioxide levels, higher temperatures, altered precipitation patterns, and other climate change impacts have already begun to affect US agriculture and forestry, with impacts expected to become more substantial in the future. There have been numerous studies of climate change impacts on agriculture or forestry, but relatively little research examining the long-term net impacts of a stabilization scenario relative to a case with unabated climate change. We provide an analysis of the potential benefits of global climate change mitigation for US agriculture and forestry through 2100, accounting for landowner decisions regarding land use, crop mix, and management practices. The analytic approach involves a combination of climate models, a crop process model (EPIC), a dynamic vegetation model used for forests (MC1), and an economic model of the US forestry and agricultural sector (FASOM-GHG). We find substantial impacts on productivity, commodity markets, and consumer and producer welfare for the stabilization scenario relative to unabated climate change, though the magnitude and direction of impacts vary across regions and commodities. Although there is variability in welfare impacts across climate simulations, we find positive net benefits from stabilization in all cases, with cumulative impacts ranging from 32.7 billion to 54.5 billion over the period 2015-2100. Our estimates contribute to the literature on potential benefits of GHG mitigation and can help inform policy decisions weighing alternative mitigation and adaptation actions.

  12. Climate change impacts on US agriculture and forestry: benefits of global climate stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Beach, Robert H.; Cai, Yongxia; Thomson, Allison; Zhang, Xuesong; Jones, Russell; McCarl, Bruce A.; Crimmins, Allison; Martinich, Jeremy; Cole, Jefferson; Ohrel, Sara; DeAngelo, Benjamin; McFarland, James; Strzepek, Kenneth; Boehlert, Brent

    2015-09-01

    Increasing atmospheric carbon dioxide levels, higher temperatures, altered precipitation patterns, and other climate change impacts have already begun to affect US agriculture and forestry, with impacts expected to become more substantial in the future. There have been numerous studies of climate change impacts on agriculture or forestry, but relatively little research examining the long-term net impacts of a stabilization scenario relative to a case with unabated climate change. We provide an analysis of the potential benefits of global climate change mitigation for US agriculture and forestry through 2100, accounting for landowner decisions regarding land use, crop mix, and management practices. The analytic approach involves a combination of climate models, a crop process model (EPIC), a dynamic vegetation model used for forests (MC1), and an economic model of the US forestry and agricultural sector (FASOM-GHG). We find substantial impacts on productivity, commodity markets, and consumer and producer welfare for the stabilization scenario relative to unabated climate change, though the magnitude and direction of impacts vary across regions and commodities. Although there is variability in welfare impacts across climate simulations, we find positive net benefits from stabilization in all cases, with cumulative impacts ranging from $32.7 billion to $54.5 billion over the period 2015-2100. Our estimates contribute to the literature on potential benefits of GHG mitigation and can help inform policy decisions weighing alternative mitigation and adaptation actions.

  13. Providing Western Regional Climate Services - Perspectives from the Western Regional Climate Center

    Science.gov (United States)

    Brown, T. J.; Redmond, K. T.

    2014-12-01

    The western United States faces distinct challenges such as persistent drought, dwindling water resources amidst an expanding population, and climate-sensitive alpine environments. The complex terrain of the region compounds these challenges. The Western Regional Climate Center (WRCC), one of six National Oceanic and Atmospheric Administration (NOAA) university-based regional climate centers, has been providing climate services since 1986 that support the unique needs of stakeholders in the mountainous region of the western U.S. This includes meteorological data, tools, and products for thousands of stations across the West, and gridded data products, such as based on PRISM for example, that are used for drought assessment among other needs. WRCC and partners have developed numerous web-based tools and products to support decision-making and research pertinent to the West. Changing climate and variability along with the diverse physical and human geographies of the western U.S. require continuous advancements in climate knowledge and applications development. Examples include the need for tools and model downscaling that support and inform adaptation, mitigation and resiliency planning; web-based analytics that would allow users to interact and explore temporal and spatial data and relationships, and products from new satellite sensors that can provide higher resolution information on soil moisture and vegetation health given the sparseness of in-situ observations for the vastness of the West. This presentation provides an overview of some insights, opportunities and challenges of providing current and future climate services in the West.

  14. Climate plan 2004; Plan climat 2004

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The Climate Plan is an action plan drawn up by the French Government to respond to the climate change challenge, first by 2010 (complying with the Kyoto Protocol target), and, secondly, beyond this date. Projections for France show that national emissions could be 10% higher than the Kyoto target in 2010 if no measures are taken. This is particularly due to increasing emissions in the sectors affecting daily life (residential-tertiary sectors, transport, etc.). For this reason, the Climate Plan contains measures affecting all sectors of the economy and the daily life of all French citizens with a view to economizing the equivalent of 54 million tonnes of CO{sub 2} each year by the year 2010, which will help to reverse the trend significantly. Beyond 2010, the Climate Plan sets out a strategy for technological research which will enable France to meet a target of reducing greenhouse gas emissions four or fivefold by 2050. (author)

  15. An extensible analysable system model

    DEFF Research Database (Denmark)

    Probst, Christian W.; Hansen, Rene Rydhof

    2008-01-01

    , this does not hold for real physical systems. Approaches such as threat modelling try to target the formalisation of the real-world domain, but still are far from the rigid techniques available in security research. Many currently available approaches to assurance of critical infrastructure security......Analysing real-world systems for vulnerabilities with respect to security and safety threats is a difficult undertaking, not least due to a lack of availability of formalisations for those systems. While both formalisations and analyses can be found for artificial systems such as software...

  16. Climate vulnerability of drinking water supplies

    Science.gov (United States)

    Selmeczi, Pál; Homolya, Emese; Rotárné Szalkai, Ágnes

    2016-04-01

    Extreme weather conditions in Hungary led to difficulties in drinking water management on diverse occasions in the past. Due to reduced water resources and the coexisting high demand for drinking water in dry summer periods the availability of a number of water supplies became insufficient therefore causing limitations in water access. In some other cases, as a result of floods and flash floods over karstic areas evolving in consequence of excessive precipitation, several water supplies had to be excluded in order to avoid the risk of infections. More frequent occurrence of extreme weather conditions and further possible changes in the future induce the necessity for an analysis of the vulnerability of drinking water resources to climate change. Since 95% of the total drinking water supply in Hungary originates from subsurface layers, significance of groundwater resources is outstanding. The aim of our work carried out in the frames of the NAGiS (National Adaptation Geo-information System) project was to build up a methodology for the study and determination of the vulnerability of drinking water supplies to climate. The task covered analyses of climatic parameters influencing drinking water supplies principally and hydrogeological characteristics of the geological media that significantly determines vulnerability. Effects on drinking water resources and their reduction or exclusion may imply societal and economic consequences therefore we extended the analyses to the investigation of possibilities concerning the adaptation capacity to changed conditions. We applied the CIVAS (Climate Impact and Vulnerability Assessment Scheme) model developed in the frames of the international climate research project CLAVIER (Climate Change and Variability: Impact on Central and Eastern Europe) to characterize climate vulnerability of drinking water supplies. The CIVAS model, being based on the combined evaluation of exposure, sensitivity and adaptability, provides a unified

  17. An ethical response to climate change

    Directory of Open Access Journals (Sweden)

    Geoffrey William Lamberton

    2014-09-01

    Full Text Available 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. Government policies required to remove barriers which are delaying a widespread and meaningful response by business to humankind’s greatest moral challenge together with the ethical implications are discussed.

  18. Proceeding of 1998-workshop on MHD computations. Study on numerical methods related to plasma confinement

    Energy Technology Data Exchange (ETDEWEB)

    Kako, T.; Watanabe, T. [eds.

    1999-04-01

    This is the proceeding of 'Study on Numerical Methods Related to Plasma Confinement' held in National Institute for Fusion Science. In this workshop, theoretical and numerical analyses of possible plasma equilibria with their stability properties are presented. These are also various talks on mathematical as well as numerical analyses related to the computational methods for fluid dynamics and plasma physics. The 14 papers are indexed individually. (J.P.N.)

  19. Reacting Flow of Hydrogen Chloride and Ammonia in Experimental and Numerical Modelling

    Institute of Scientific and Technical Information of China (English)

    Dariusz Kardas; Katarzyna Falkowska

    2003-01-01

    The experimental and numerical investigations of the flow with reaction of two gases: hydrogen chloride HCl and ammonia NH_3 were performed.The article contains description of the visualisation method of the formation and flow of particles of ammonia chloride NH_4Cl.Analyses of mean concentration and variance of concentration fluctuations of dispersed phase were performed for different outputs of gases.Numerical calculations were performed for analysed phenomenon. Both numerical and visualisation results were matched and compared.

  20. Blue Jeans, Chewing Gum and Climate Change Litigation: American Exports to Europe

    OpenAIRE

    Daniel G Hare

    2013-01-01

    This paper analyses how American-style climate change litigation might be adopted by the European Union ('EU') and projects potential methods by which the EU might employ the US model, if it indeed chooses to take the climate change battle to the courts. By synthesising existing US case law in the environment and climate change fields, the paper roughly defines the 'American model' of climate change litigation as parens patriae actions, oftentimes based in the tort of public nuisance, brought...

  1. Data Visualization and Analysis for Climate Studies using NASA Giovanni Online System

    Science.gov (United States)

    Rui, Hualan; Leptoukh, Gregory; Lloyd, Steven

    2008-01-01

    With many global earth observation systems and missions focused on climate systems and the associated large volumes of observational data available for exploring and explaining how climate is changing and why, there is an urgent need for climate services. Giovanni, the NASA GES DISC Interactive Online Visualization ANd ANalysis Infrastructure, is a simple to use yet powerful tool for analysing these data for research on global warming and climate change, as well as for applications to weather. air quality, agriculture, and water resources,

  2. Quality management and perceptions of teamwork and safety climate in European hospitals

    OpenAIRE

    Kristensen, S; Hammer, A.; Bartels, P; Sunol, R.; Groene, O.; Thompson, CA; Arah, OA; Kutaj-Wasikowska, H; Michel, P.; Wagner, C

    2015-01-01

    This study aimed to investigate the associations of quality management systems with teamwork and safety climate, and to describe and compare differences in perceptions of teamwork climate and safety climate among clinical leaders and frontline clinicians.We used a multi-method, cross-sectional approach to collect survey data of quality management systems and perceived teamwork and safety climate. Our data analyses included descriptive and multilevel regression methods.Data on implementation o...

  3. Tropical deforestation and climate change

    Energy Technology Data Exchange (ETDEWEB)

    Ebeling, J.

    2006-08-15

    This dissertation evaluates recent proposals to include tropical deforestation into international climate change mitigation strategies. Deforestation is responsible for up to 25 percent of global greenhouse gas emissions. The research aim here is to evaluate implications of a range of policy options for the environmental effectiveness of a prospective agreement, as well as for its political and economic attractiveness for different countries and stakeholders. A literature review, 48 key stakeholder interviews, analyses of submissions to the United Nations Framework Convention on Climate Change (UNFCCC), modelling approaches and statistical analyses were carried out to answer these questions. On this basis the study identifies potential deal breakers and explores possible solutions to existing 'real' and perceived obstacles. Findings suggest that, given sufficient political will, an effective agreement between current UNFCCC Parties is feasible and that existing concerns can be addressed in pragmatic ways. Among the different policy alternatives, creating a new carbon trading mechanism under a post-2012 Kyoto regime is likely to deliver greatest economic and environmental benefits. Measuring emission reductions against national-level baselines based on historical base periods would increase the environmental integrity of resulting carbon credits. The study also finds that potential monetary benefits are distributed very unevenly between potential host countries, and that this may partly explain current negotiation positions. Complementary approaches, not based on emission trading, may have to be developed to foster broader support for an agreement. Finally, setting more ambitious emission reduction targets for industrialised countries would overcome concerns about 'flooding' of carbon markets, and would make the most of a unique opportunity to tackle both climate change and deforestation.

  4. Climate@Home: Crowdsourcing Climate Change Research

    Science.gov (United States)

    Xu, C.; Yang, C.; Li, J.; Sun, M.; Bambacus, M.

    2011-12-01

    Climate change deeply impacts human wellbeing. Significant amounts of resources have been invested in building super-computers that are capable of running advanced climate models, which help scientists understand climate change mechanisms, and predict its trend. Although climate change influences all human beings, the general public is largely excluded from the research. On the other hand, scientists are eagerly seeking communication mediums for effectively enlightening the public on climate change and its consequences. The Climate@Home project is devoted to connect the two ends with an innovative solution: crowdsourcing climate computing to the general public by harvesting volunteered computing resources from the participants. A distributed web-based computing platform will be built to support climate computing, and the general public can 'plug-in' their personal computers to participate in the research. People contribute the spare computing power of their computers to run a computer model, which is used by scientists to predict climate change. Traditionally, only super-computers could handle such a large computing processing load. By orchestrating massive amounts of personal computers to perform atomized data processing tasks, investments on new super-computers, energy consumed by super-computers, and carbon release from super-computers are reduced. Meanwhile, the platform forms a social network of climate researchers and the general public, which may be leveraged to raise climate awareness among the participants. A portal is to be built as the gateway to the climate@home project. Three types of roles and the corresponding functionalities are designed and supported. The end users include the citizen participants, climate scientists, and project managers. Citizen participants connect their computing resources to the platform by downloading and installing a computing engine on their personal computers. Computer climate models are defined at the server side. Climate

  5. Loss of frugivore seed dispersal services under climate change.

    Science.gov (United States)

    Mokany, Karel; Prasad, Soumya; Westcott, David A

    2014-05-27

    The capacity of species to track shifting climates into the future will strongly influence outcomes for biodiversity under a rapidly changing climate. However, we know remarkably little about the dispersal abilities of most species and how these may be influenced by climate change. Here we show that climate change is projected to substantially reduce the seed dispersal services provided by frugivorous vertebrates in rainforests across the Australian Wet Tropics. Our model projections show reductions in both median and long-distance seed dispersal, which may markedly reduce the capacity of many rainforest plant species to track shifts in suitable habitat under climate change. However, our analyses suggest that active management to maintain the abundances of a small set of important frugivores under climate change could markedly reduce the projected loss of seed dispersal services and facilitate shifting distributions of rainforest plant species.

  6. Betting and Belief: Prediction Markets and Attribution of Climate Change

    CERN Document Server

    Nay, John J; Gilligan, Jonathan M

    2016-01-01

    Despite much scientific evidence, a large fraction of the American public doubts that greenhouse gases are causing global warming. We present a simulation model as a computational test-bed for climate prediction markets. Traders adapt their beliefs about future temperatures based on the profits of other traders in their social network. We simulate two alternative climate futures, in which global temperatures are primarily driven either by carbon dioxide or by solar irradiance. These represent, respectively, the scientific consensus and a hypothesis advanced by prominent skeptics. We conduct sensitivity analyses to determine how a variety of factors describing both the market and the physical climate may affect traders' beliefs about the cause of global climate change. Market participation causes most traders to converge quickly toward believing the "true" climate model, suggesting that a climate market could be useful for building public consensus.

  7. Soil Moisture-Ecosystem-Climate Interactions in a Changing Climate

    Science.gov (United States)

    Seneviratne, S. I.; Davin, E.; Hirschi, M.; Mueller, B.; Orlowsky, B.; Teuling, A.

    2011-12-01

    Soil moisture is a key variable of the climate system. It constrains plant transpiration and photosynthesis in several regions of the world, with consequent impacts on the water, energy and biogeochemical cycles (e.g. Seneviratne et al. 2010). Moreover it is a storage component for precipitation and radiation anomalies, inducing persistence in the climate system. Finally, it is involved in a number of feedbacks at the local, regional and global scales, and plays a major role in climate-change projections. This presentation will provide an overview on these interactions, based on several recent publications (e.g. Seneviratne et al. 2006, Orlowsky and Seneviratne 2010, Teuling et al. 2010, Hirschi et al. 2011). In particular, it will highlight possible impacts of soil moisture-ecosystem coupling for climate extremes such as heat waves and droughts, and the resulting interconnections between biophysical and biogeochemical feedbacks in the context of climate change. Finally, it will also address recent regional- to global-scale trends in land hydrology and ecosystem functioning, as well as issues and potential avenues for investigating these trends (e.g. Jung et al. 2010, Mueller et al. 2011). References Hirschi, M., S.I. Seneviratne, V. Alexandrov, F. Boberg, C. Boroneant, O.B. Christensen, H. Formayer, B. Orlowsky, and P. Stepanek, 2011: Observational evidence for soil-moisture impact on hot extremes in southeastern Europe. Nature Geoscience, 4, 17-21, doi:10.1038/ngeo1032. Jung, M., et al., 2010: Recent decline in the global land evapotranspiration trend due to limited moisture supply. Nature, 467, 951-954. doi:10.1038/nature09396 Mueller, B., S.I. Seneviratne, et al.: Evaluation of global observations-based evapotranspiration datasets and IPCC AR4 simulations, Geophys. Res. Lett., 38, L06402, doi:10.1029/2010GL046230 Orlowsky, B., and S.I. Seneviratne, 2010: Statistical analyses of land-atmosphere feedbacks and their possible pitfalls. J. Climate, 23(14), 3918

  8. Climate Literacy Ambassadors

    Science.gov (United States)

    Ackerman, S. A.; Mooney, M. E.

    2011-12-01

    The Climate Literacy Ambassadors program is a collaborative effort to advance climate literacy led by the Cooperative Institute of Meteorological Satellite Studies (CIMSS) at the University of Wisconsin-Madison. With support from NASA, CIMSS is coordinating a three-tiered program to train G6-12 teachers to be Ambassadors of Climate Literacy in their schools and communities. The complete training involves participation at a teacher workshop combined with web-based professional development content around Global and Regional Climate Change. The on-line course utilizes e-learning technology to clarify graphs and concepts from the 2007 Intergovernmental Panel on Climate Change Summary for Policy Makers with content intricately linked to the Climate Literacy: The Essential Principles of Climate Science. Educators who take the course for credit can develop lesson plans or opt for a project of their choosing. This session will showcase select lesson plans and projects, ranging from a district-wide action plan that engaged dozens of teachers to Ambassadors volunteering at the Aldo Leopold Climate Change Nature Center to a teacher who tested a GLOBE Student Climate Research Campaign (SCRC) learning project with plans to participate in the SCRC program. Along with sharing successes from the CIMSS Climate Literacy Ambassadors project, we will share lessons learned related to the challenges of sustaining on-line virtual educator communities.

  9. Evaluation "Risk analyses of agroparks"

    NARCIS (Netherlands)

    Ge, L.

    2011-01-01

    Dit TransForum project richt zich op analyse van de onzekerheden en mogelijkheden van agroparken. Dit heeft geleid tot een risicomodel dat de kwalitatieve en/of kwantitatieve onzekerheden van een agropark project in kaart brengt. Daarmee kunnen maatregelen en managementstrategiën worden geïdentifice

  10. Descriptive Analyses of Mechanical Systems

    DEFF Research Database (Denmark)

    Andreasen, Mogens Myrup; Hansen, Claus Thorp

    2003-01-01

    Forord Produktanalyse og teknologianalyse kan gennmføres med et bredt socio-teknisk sigte med henblik på at forstå kulturelle, sociologiske, designmæssige, forretningsmæssige og mange andre forhold. Et delområde heri er systemisk analyse og beskrivelse af produkter og systemer. Nærværende kompend...

  11. First Numerical Simulations of Anomalous Hydrodynamics

    CERN Document Server

    Hongo, Masaru; Hirano, Tetsufumi

    2013-01-01

    Anomalous hydrodynamics is a low-energy effective theory that captures effects of quantum anomalies. We develop a numerical code of anomalous hydrodynamics and apply it to dynamics of heavy-ion collisions, where anomalous transports are expected to occur. This is the first attempt to perform fully non-linear numerical simulations of anomalous hydrodynamics. We discuss implications of the simulations for possible experimental observations of anomalous transport effects. From analyses of the charge-dependent elliptic flow parameters ($v_2^\\pm$) as a function of the net charge asymmetry $A_\\pm$, we quantitatively verify that the linear dependence of $\\Delta v_2 \\equiv v_2^- - v_2^+$ on the net charge asymmetry $A_\\pm$ cannot be regarded as a sensitive signal of anomalous transports, contrary to previous studies. We, however, find that the intercept $\\Delta v_2(A_\\pm=0)$ is sensitive to anomalous transport effects.

  12. Numerical Simulation of the Lightning Return Stroke.

    Science.gov (United States)

    da Frota Mattos, Marcos Andre

    Available from UMI in association with The British Library. Requires signed TDF. Several lightning return stroke models were developed in this work. Initially very simple models were developed, and subsequently many of the main features of the channel were added. The corona effect, the geometrical parameters, non-linear losses and the cloud losses are these features. To solve the RLC network model of the channel the numerical technique known as TLM was used. A numerical sensitivity study was made to analyse the influence of the filtering and the Gibbs effects on the results. A sensitivity study of the channel's parameters was also made. For the first time three of the main measured lightning channel quantities were calculated showing good agreement with observations. These quantities are the electromagnetic field, current waveshape at ground and the velocity of propagation. The surge impedence and the current rise-time were also calculated at all heights.

  13. Numerical Analysis of Dynamic Direct Tension and Direct Compression Tests

    Science.gov (United States)

    1993-01-01

    material model employed in the nonlinear analysis is a hypoelastic model based on a uniaxial stress-strain relation (Figure 18) that is generalized to...rates. Both an elastic and inelastic concrete material model were employed in all numerical analyses. The modes of failure predicted by the numerical... models ; (2) augmenting the system by adding other typical scenarios, with the ultimate goal of expanding it into a general task-oriented system/shell; and

  14. Experimental and Numerical Analysis of Steel Joints in Round Wood

    Directory of Open Access Journals (Sweden)

    Mikolášek David

    2014-12-01

    Full Text Available The paper analyses a drawn steel joint in round logs for which several types of reinforcements have been proposed. The load-carrying capacity of the reinforcements have been tested in laboratories. At the same time, numerical modelling has been performed - it has focused, in particular, on rigidity of the joints during the loading process. Physical and geometrical nonlinearities have been taken into account. The Finite Element Method and 3D computation models have been used in the numerical calculations.

  15. Study on the Trace Species in the Stratosphere and Their Impact on Climate

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The trace gases (O3,HCl,CH4,H2O,NO,NO2) in the stratosphere play an important role, not only in the photochemical processes in which the ozone layer destroyed, but also in the radiative processes. In this paper, we review the works on the distribution and variation of the trace gases in the stratosphere and their impact on climate, which have been carried out at the University of Science and Technology of China in the recent 20 years. The Halogen Occultation Experiment (HALOE) data were used to analyse the distribution and variation of the mixing ratio of these trace gases and the temperature trends in the stratosphere in the most recent decade. And the reanalyzed National Centers of Environmental Prediction (NCEP)/NCAR data were also used to give the temperature trends and compared with the results from HALOE data. Numerical simulations were also carried out to study the impact of ozone depletion on the global climate. In this review, the distributions of the trace gases, especially those over the Qinghai-Xizang Plateau, are discussed, and the variations and trends for the trace gases in various levels in the stratosphere have been given for the most recent decade. The temperature variation and the cooling trend obtained from HALOE data in the middle and lower stratosphere for the last 13 years are significant, which agree well with the results from NCEP/NCAR data. While the temperature trend in the upper stratosphere in this period do not seem to have much cooling. The numerical simulations show that either the Antarctic ozone hole or the ozone valley over Qinghai-Xizang Plateau affect not only the temperature and circulation in the stratosphere, but also the temperature, pressure and wind fields in the troposphere, then lead to the global climate change.

  16. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    Aim of project:To analyse and model the transient thermal field from arc welding (SMAW, V-shaped buttweld in 15mm plate) and to some extend the mechanical response due to the thermal field. - To implement this model in a general purpose finite element program such as ABAQUS.The simulation...... stress is also taken into account.Work carried out:With few means it is possible to define a thermal model which describes the thermal field from the welding process in reasonable agreement with reality. Identical results are found with ABAQUS and Rosenthal’s analytical solution of the governing heat...... transfer equation under same conditions. It is relative easy tointroduce boundary conditions such as convection and radiation where not surprisingly the radiation has the greatest influence especially from the high temperature regions in the weld pool and the heat affected zone.Due to the large temperature...

  17. The spatial distribution of extreme climate events, another climate inequity for the world’s most vulnerable people

    Science.gov (United States)

    Green, Donna

    2016-09-01

    Does the climate change signal emerge equally from internal climate variability across the globe? If not, are there particular locations where temperature extremes might disproportionately affect specific populations? The letter by Harrington et al (2016 Environ. Res. Lett. 11 055007) argues that people living in low latitude countries, which contain the majority of the world’s poorest people, are—and will continue to be—disproportionately affected by increases in temperature extremes. Due to differences in expertise of climate scientists, and climate impact and adaptation scientists, few climate extreme event analyses are spatially disaggregated and linked to local populations’ socio-economic characteristics. The research presented in this letter begins to bridge this gap by providing evidence of inequitable spatial impacts from climate extremes on the world’s poorest people.

  18. An Overview of BCC Climate System Model Development and Application for Climate Change Studies

    Institute of Scientific and Technical Information of China (English)

    WU Tongwen; WU Fanghua; LIU Yiming; ZHANG Fang; SHI Xueli; CHU Min; ZHANG Jie; FANG Yongjie; WANG Fang; LU Yixiong; LIU Xiangwen; SONG Lianchun; WEI Min; LIU Qianxia; ZHOU Wenyan; DONG Min; ZHAO Qigeng; JI Jinjun; Laurent LI; ZHOU Mingyu; LI Weiping; WANG Zaizhi; ZHANG Hua; XIN Xiaoge; ZHANG Yanwu; ZHANG Li; LI Jianglong

    2014-01-01

    This paper reviews recent progress in the development of the Beijing Climate Center Climate System Model (BCC-CSM) and its four component models (atmosphere, land surface, ocean, and sea ice). Two recent versions are described: BCC-CSM1.1 with coarse resolution (approximately 2.8125◦×2.8125◦) and BCC-CSM1.1(m) with moderate resolution (approximately 1.125◦×1.125◦). Both versions are fully cou-pled climate-carbon cycle models that simulate the global terrestrial and oceanic carbon cycles and include dynamic vegetation. Both models well simulate the concentration and temporal evolution of atmospheric CO2 during the 20th century with anthropogenic CO2 emissions prescribed. Simulations using these two versions of the BCC-CSM model have been contributed to the Coupled Model Intercomparison Project phase fi ve (CMIP5) in support of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). These simulations are available for use by both national and international communities for investigating global climate change and for future climate pro jections. Simulations of the 20th century climate using BCC-CSM1.1 and BCC-CSM1.1(m) are presented and validated, with particular focus on the spatial pattern and seasonal evolution of precipitation and surface air temperature on global and continental scales. Simulations of climate during the last millennium and pro jections of climate change during the next century are also presented and discussed. Both BCC-CSM1.1 and BCC-CSM1.1(m) perform well when compared with other CMIP5 models. Preliminary analyses in-dicate that the higher resolution in BCC-CSM1.1(m) improves the simulation of mean climate relative to BCC-CSM1.1, particularly on regional scales.