WorldWideScience

Sample records for model horizontal resolution

  1. Influence of horizontal resolution and ensemble size on model performance

    CSIR Research Space (South Africa)

    Dalton, A

    2014-10-01

    Full Text Available Computing costs increase with an increase in global model resolution and ensemble size. This paper strives to determine the extent to which resolution and ensemble size affect seasonal forecast skill when simulating mid-summer rainfall totals over...

  2. The horizontal resolution of MIPAS

    Directory of Open Access Journals (Sweden)

    J.-C. Lambert

    2009-02-01

    Full Text Available Limb remote sensing from space provides atmospheric composition measurements at high vertical resolution while the information is smeared in the horizontal domain. The horizontal components of two-dimensional (altitude and along-track coordinate averaging kernels of a limb retrieval constrained to horizontal homogeneity can be used to estimate the horizontal resolution of limb retrievals. This is useful for comparisons of measured data with modeled data, to construct horizontal observation operators in data assimilation applications or when measurements of different horizontal resolution are intercompared. We present these averaging kernels for retrievals of temperature, H2O, O3, CH4, N2O, HNO3 and NO2 from MIPAS (Michelson Interferometer for Passive Atmospheric Sounding high-resolution limb emission spectra. The horizontal smearing of a MIPAS retrieval in terms of full width at half maximum of the rows of the horizontal averaging kernel matrix varies typically between about 200 and 350 km for most species, altitudes and atmospheric conditions. The range where 95% of the information originates from varies from about 260 to 440 km for these cases. This information spread is smaller than the MIPAS horizontal sampling, i.e. MIPAS data are horizontally undersampled, and the effective horizontal resolution is driven by the sampling rather than the smearing. The point where the majority of the information originates from is displaced from the tangent point towards the satellite by typically less than 10 km for trace gas profiles and about 50 to 100 km for temperature, with a few exceptions for uppermost altitudes. The geolocation of a MIPAS profile is defined as the tangent point of the middle line of sight in a MIPAS limb scan. The majority of the information displacement with respect to this nominal geolocation of the measurement is caused by the satellite movement and the geometrical

  3. Future changes in regional precipitation simulated by a half-degree coupled climate model: Sensitivity to horizontal resolution

    Science.gov (United States)

    Shields, Christine A.; Kiehl, Jeffrey T.; Meehl, Gerald A.

    2016-06-01

    The global fully coupled half-degree Community Climate System Model Version 4 (CCSM4) was integrated for a suite of climate change ensemble simulations including five historical runs, five Representative Concentration Pathway 8.5 [RCP8.5) runs, and a long Pre-Industrial control run. This study focuses on precipitation at regional scales and its sensitivity to horizontal resolution. The half-degree historical CCSM4 simulations are compared to observations, where relevant, and to the standard 1° CCSM4. Both the half-degree and 1° resolutions are coupled to a nominal 1° ocean. North American and South Asian/Indian monsoon regimes are highlighted because these regimes demonstrate improvements due to higher resolution, primarily because of better-resolved topography. Agriculturally sensitive areas are analyzed and include Southwest, Central, and Southeast U.S., Southern Europe, and Australia. Both mean and extreme precipitation is discussed for convective and large-scale precipitation processes. Convective precipitation tends to decrease with increasing resolution and large-scale precipitation tends to increase. Improvements for the half-degree agricultural regions can be found for mean and extreme precipitation in the Southeast U.S., Southern Europe, and Australian regions. Climate change responses differ between the model resolutions for the U.S. Southwest/Central regions and are seasonally dependent in the Southeast and Australian regions. Both resolutions project a clear drying signal across Southern Europe due to increased greenhouse warming. Differences between resolutions tied to the representation of convective and large-scale precipitation play an important role in the character of the climate change and depend on regional influences.

  4. Assimilation of radar reflectivity into the LM COSMO model with a high horizontal resolution

    Czech Academy of Sciences Publication Activity Database

    Sokol, Zbyněk; Řezáčová, Daniela

    2006-01-01

    Roč. 13, č. 4 (2006), s. 317-330 ISSN 1350-4827 R&D Projects: GA ČR GA205/04/0114 Institutional research plan: CEZ:AV0Z30420517 Keywords : precipitation forecast * assimilation * radar reflectivity * NWP model * local storm Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.453, year: 2006

  5. Performance of European chemistry transport models as function of horizontal resolution

    NARCIS (Netherlands)

    Schaap, M.; Cuvelier, C.; Hendriks, C.; Bessagnet, B.; Baldasano, J.M.; Colette, A.; Thunis, P.; Karam, D.; Fagerli, H.; Graff, A.; Kranenburg, R.; Nyiri, A.; Pay, M.T.; Rouïl, L.; Schulz, M.; Simpson, D.; Stern, R.; Terrenoire, E.; Wind, P.

    2015-01-01

    Air pollution causes adverse effects on human health as well as ecosystems and crop yield and also has an impact on climate change trough short-lived climate forcers. To design mitigation strategies for air pollution, 3D Chemistry Transport Models (CTMs) have been developed to support the decision

  6. Air quality over Europe and Iberian Peninsula for 2004 at high horizontal resolution: evaluation of the CALIOPE modelling system

    Science.gov (United States)

    Jorba, O.; Piot, M.; Pay, M. T.; Jiménez-Guerrero, P.; López, E.; Pérez, C.; Gassó, S.; Baldasano, J. M.

    2009-09-01

    In the frame of the CALIOPE project (Baldasano et al., 2008a), a high-resolution air quality forecasting system, WRF-ARW/HERMES/CMAQ/DREAM, is under development and applied to the European domain (12km x 12km, 1hr) as well as to the Iberian Peninsula domain (4km x 4km, 1hr) to provide air quality forecasts for Spain (http://www.bsc.es/caliope/). The simulation of such high-resolution model system is possible by its implementation on the MareNostrum supercomputer. To reassure potential users and reduce uncertainties, the model system must be evaluated to assess its performances in terms of air quality levels and dynamics reproducibility. The present contribution describes a thorough quantitative evaluation study performed for a reference year (2004). CALIOPE is a complex system that integrates a variety of environmental models. WRF-ARW provides high-resolution meteorological fields to the system. It is configured with 38 vertical layers reaching up to 50 hPa. Meteorological initial and boundary conditions are obtained from the NCEP final analysis data. The HERMES emission model (Baldasano et al., 2008b) computes the emissions for the Iberian Peninsula simulation at 4 km horizontal resolution every hour using a bottom-up approach. For the European domain, HERMES disaggregates the EMEP expert emission inventory for 2004. The CMAQ chemical transport model solves the physico-chemical processes in the system. The vertical resolution of CMAQ for gas-phase and aerosols has been increased from 8 to 15 layers in order to simulate vertical exchanges more accurately. Chemical boundary conditions are provided by the LMDz-INCA2 global climate-chemistry model (see Hauglustaine et al., 2004). Finally, the DREAM model simulates long-range transport of mineral dust over the domains under study. In order to evaluate the performances of the CALIOPE system, model simulations were compared with ground-based measurements from the EMEP and Spanish air quality networks. For the European

  7. Alleviating tropical Atlantic sector biases in the Kiel climate model by enhancing horizontal and vertical atmosphere model resolution: climatology and interannual variability

    Science.gov (United States)

    Harlaß, Jan; Latif, Mojib; Park, Wonsun

    2018-04-01

    We investigate the quality of simulating tropical Atlantic (TA) sector climatology and interannual variability in integrations of the Kiel climate model (KCM) with varying atmosphere model resolution. The ocean model resolution is kept fixed. A reasonable simulation of TA sector annual-mean climate, seasonal cycle and interannual variability can only be achieved at sufficiently high horizontal and vertical atmospheric resolution. Two major reasons for the improvements are identified. First, the western equatorial Atlantic westerly surface wind bias in spring can be largely eliminated, which is explained by a better representation of meridional and especially vertical zonal momentum transport. The enhanced atmospheric circulation along the equator in turn greatly improves the thermal structure of the upper equatorial Atlantic with much reduced warm sea surface temperature (SST) biases. Second, the coastline in the southeastern TA and steep orography are better resolved at high resolution, which improves wind structure and in turn reduces warm SST biases in the Benguela upwelling region. The strongly diminished wind and SST biases at high atmosphere model resolution allow for a more realistic latitudinal position of the intertropical convergence zone. Resulting stronger cross-equatorial winds, in conjunction with a shallower thermocline, enable a rapid cold tongue development in the eastern TA in boreal spring. This enables simulation of realistic interannual SST variability and its seasonal phase locking in the KCM, which primarily is the result of a stronger thermocline feedback. Our findings suggest that enhanced atmospheric resolution, both vertical and horizontal, could be a key to achieving more realistic simulation of TA climatology and interannual variability in climate models.

  8. Vertical and horizontal resolution dependency in the model representation of tracer dispersion along the continental slope in the northern Gulf of Mexico

    Science.gov (United States)

    Bracco, Annalisa; Choi, Jun; Kurian, Jaison; Chang, Ping

    2018-02-01

    A set of nine regional ocean model simulations at various horizontal (from 1 to 9 km) and vertical (from 25 to 150 layers) resolutions with different vertical mixing parameterizations is carried out to examine the transport and mixing of a passive tracer released near the ocean bottom over the continental slope in the northern Gulf of Mexico. The release location is in proximity to the Deepwater Horizon oil well that ruptured in April 2010. Horizontal and diapycnal diffusivities are calculated and their dependence on the model set-up and on the representation of mesoscale and submesoscale circulations is discussed. Horizontal and vertical resolutions play a comparable role in determining the modeled horizontal diffusivities. Vertical resolution is key to a proper representation of passive tracer propagation and - in the case of the Gulf of Mexico - contributes to both confining the tracer along the continental slope and limiting its vertical spreading. The choice of the tracer advection scheme is also important, with positive definiteness in the tracer concentration being achieved at the price of spurious mixing across density surfaces. In all cases, however, the diapycnal mixing coefficient derived from the model simulations overestimates the observed value, indicating an area where model improvement is needed.

  9. Response of precipitation extremes to idealized global warming in an aqua-planet climate model: Towards robust projection across different horizontal resolutions

    Energy Technology Data Exchange (ETDEWEB)

    Li, F.; Collins, W.D.; Wehner, M.F.; Williamson, D.L.; Olson, J.G.

    2011-04-15

    Current climate models produce quite heterogeneous projections for the responses of precipitation extremes to future climate change. To help understand the range of projections from multimodel ensembles, a series of idealized 'aquaplanet' Atmospheric General Circulation Model (AGCM) runs have been performed with the Community Atmosphere Model CAM3. These runs have been analysed to identify the effects of horizontal resolution on precipitation extreme projections under two simple global warming scenarios. We adopt the aquaplanet framework for our simulations to remove any sensitivity to the spatial resolution of external inputs and to focus on the roles of model physics and dynamics. Results show that a uniform increase of sea surface temperature (SST) and an increase of low-to-high latitude SST gradient both lead to increase of precipitation and precipitation extremes for most latitudes. The perturbed SSTs generally have stronger impacts on precipitation extremes than on mean precipitation. Horizontal model resolution strongly affects the global warming signals in the extreme precipitation in tropical and subtropical regions but not in high latitude regions. This study illustrates that the effects of horizontal resolution have to be taken into account to develop more robust projections of precipitation extremes.

  10. Impact of horizontal resolution on prediction of tropical cyclones over ...

    Indian Academy of Sciences (India)

    Two cyclones, which formed over the Bay of Bengal during the years 1995 and 1997, are simulated using a regional weather prediction model with two horizontal resolutions of 165km and 55 km. The model is found to perform reasonably well towards simulation of the storms. The structure, intensity and track of the cyclones ...

  11. Indian Summer Monsoon Simulations: Usefulness of Increasing Horizontal Resolution, Manual Tuning, and Semi-Automatic Tuning in Reducing Present-Day Model Biases.

    Science.gov (United States)

    Anand, Abhishek; Mishra, Saroj K; Sahany, Sandeep; Bhowmick, Mansi; Rawat, Janmejai Singh; Dash, S K

    2018-02-23

    Coupled Global Climate Models (CGCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) are unable to resolve the spatial and temporal characteristics of the South Asian Monsoon satisfactorily. A CGCM with the capability to reliably project the global as well as the regional climatic features would be a valuable tool for scientists and policymakers. Analysis of 28 CMIP5 models highlights varying degree of biases in precipitation and 2 m surface air temperature (T2m) over south Asia, and the Community Earth System Model (CESM) developed at the National Center for Atmospheric Research is found to be one of the best performing models. However, like all other CMIP5 models, CESM also has some inherent model biases. Using CESM, it is found that the precipitation and T2M biases reduce with increase in the model horizontal resolution from 2° to 0.5°. Further, a few deep convective parameters in the Zhang-McFarlane convection scheme are tuned for 2° and 1° model resolutions using both manual and semi-automatic model tuning methods. Comparing results from the two tuning methods we find that the performance of the manually tuned model is better than that of the semi-automated one.

  12. The Sensitivity of Heavy Precipitation to Horizontal Resolution, Domain Size, and Rain Rate Assimilation: Case Studies with a Convection-Permitting Model

    Directory of Open Access Journals (Sweden)

    Xingbao Wang

    2016-01-01

    Full Text Available The Australian Community Climate and Earth-System Simulator (ACCESS is used to test the sensitivity of heavy precipitation to various model configurations: horizontal resolution, domain size, rain rate assimilation, perturbed physics, and initial condition uncertainties, through a series of convection-permitting simulations of three heavy precipitation (greater than 200 mm day−1 cases in different synoptic backgrounds. The larger disparity of intensity histograms and rainfall fluctuation caused by different model configurations from their mean and/or control run indicates that heavier precipitation forecasts have larger uncertainty. A cross-verification exercise is used to quantify the impacts of different model parameters on heavy precipitation. The dispersion of skill scores with control run used as “truth” shows that the impacts of the model resolution and domain size on the quantitative precipitation forecast are not less than those of perturbed physics and initial field uncertainties in these not intentionally selected heavy precipitation cases. The result indicates that model resolution and domain size should be considered as part of probabilistic precipitation forecasts and ensemble prediction system design besides the model initial field uncertainty.

  13. The Evaluation of the Spanish Air Quality Modelling System: CALIOPE. Dynamics and Chemistry over Europe and Iberian Peninsula for 2004 at high horizontal resolution

    Science.gov (United States)

    Piot, M.; Pay, M.; Jorba, O.; Lopez, E.; Pirez, C.; Gasso, S.; Baldasano, J. M.

    2009-12-01

    In Europe, human exposure to air pollution often exceeds standards set by the EU commission (Directives 1996/62/EC, 2002/3/EC, 2008/50/EC) and the World Health Organization (WHO). Urban/suburban areas are predominantly impacted upon, although exceedances of particulate matter (PM10 and PM2.5) and Ozone (O3) also take place in rural areas. Within the CALIOPE project, a high-resolution air quality forecasting system, namely WRF-ARW/HERMES04/CMAQ/BSC-DREAM, has been developed and applied to the European domain (12x12 sq. km, 1hr) as well as the Spanish domain (4x4 sq. km, 1hr). The simulation of such high-resolution model system has been made possible by its implementation on the MareNostrum supercomputer. This contribution describes a thorough quantitative evaluation study performed for the reference year 2004. The WRF-ARW meteorological model contains 38 vertical layers reaching up to 50 hPa. The vertical resolution of the CMAQ chemistry-transport model for gas-phase and aerosols has been increased from 8 to 15 layers in order to simulate vertical exchanges more accurately. Gas phase boundary conditions are provided by the LMDz-INCA2 global climate-chemistry model. For the European simulation, emissions are disaggregated from the EMEP emission inventory for 2004 to the utilized resolution using the criteria implemented in the HERMES04 emission model. The HERMES04 model system, running through a bottom-up approach, is used to estimate emissions for Spain at a 1x1 sq. km horizontal resolution, every hour. In order to evaluate the performances of the CALIOPE system, the model simulation for Europe was compared with ground-based measurements from the EMEP and the Spanish air quality networks (total of 60 stations for O3, 43 for NO2, 31 for SO2, 25 for PM10 and 16 for PM2.5). The model simulation for Europe satisfactorily reproduces O3 concentrations throughout the year (annual correlation: 0.66) with relatively small errors: MNGE values range from 13% to 26%, and MNBE

  14. Assimilation of the radar-derived water vapour mixing ratio into the LM COSMO model with a high horizontal resolution

    Czech Academy of Sciences Publication Activity Database

    Sokol, Zbyněk; Řezáčová, Daniela

    2009-01-01

    Roč. 92, č. 3 (2009), s. 331-342 ISSN 0169-8095. [International workshop on precipitation in urban areas /7./. St. Moritz, 07.12.2006-10.12.2006] R&D Projects: GA ČR GA205/07/0905; GA MŠk OC 112 Institutional research plan: CEZ:AV0Z30420517 Keywords : Precipitation * Local convective storm assimilation * Radar reflectivity * NWP model Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.811, year: 2009

  15. Evaluating the CALIOPE air quality modelling system: dynamics and chemistry over Europe and Iberian Peninsula for 2004 at high horizontal resolution

    Science.gov (United States)

    Piot, M.; Pay, M. T.; Jorba, O.; Baldasano, J. M.; Jiménez-Guerrero, P.; López, E.; Pérez, C.; Gassó, S.

    2009-04-01

    Peninsula simulation at 4 km horizontal resolution, every hour. In order to evaluate the performances of the CALIOPE system, model simulations were compared with ground-based measurements from the EMEP and Spanish air quality networks. For the European domain, 45 stations have been used to evaluate NO2, 60 for O3, 39 for SO2, 25 for PM10 and 16 for PM2.5. On the other hand, the Iberian Peninsula domain has been evaluated against 75 NO2 stations, 84 O3 stations, 69 for SO2, and 46 for PM10. Such large number of observations allows us to provide a detailed discussion of the model skills over quite different geographical locations and meteorological situations. The model simulation for Europe satisfactorily reproduces O3 concentrations throughout the year with relatively small errors: MNGE values range from 13% to 24%, and MNBE values show a slight negative bias ranging from -15% to 0%. These values lie within the range defined by the US-EPA guidelines (MNGE: +/- 30-35%; MNBE: +/- 10-15%). NO2 is less accurately simulated, with a mean MNBE of -47% caused by an overall underestimation in concentrations. The reproduction of SO2 concentrations is relatively correct but false peaks are reported (mean MNBE=22%). The simulated variation of particulate matter is reliable, with a mean correlation of 0.5. False peaks were reduced by use of an improved 8-bin aerosol description in the DREAM dust model, but mean aerosol levels are still underestimated. This problem is most probably related to uncertainties in our knowledge of the sources and in the description of the sulfate chemistry. The model simulation for Europe will be used to force the nested high-resolution simulation of the Iberian Peninsula. The performances of the latter will be also presented. Such high resolution simulation will allow analysing the small scale features observed over Spain. REFERENCES Baldasano J.M, P. Jiménez-Guerrero, O. Jorba, C. Pérez, E. López, P. Güereca, F. Martin, M. García-Vivanco, I. Palomino

  16. Simulations of the transport and deposition of {sup 137}Cs over Europe after the Chernobyl Nuclear Power Plant accident. Influence of varying emission-altitude and model horizontal and vertical resolution

    Energy Technology Data Exchange (ETDEWEB)

    Evangeliou, N.; Balkanski, Y.; Cozic, A. [Institut Pierre et Simon Laplace, Gif sur Yvette (France). Lab. des Sciences du Climat et de l' Environnement; Moeller, A.P. [Univ. Paris-Sud, Orsay (France). Lab. d' Ecologie, Systematique et Evolution

    2013-07-01

    The coupled model LMDZORINCA has been used to simulate the transport, wet and dry deposition of the radioactive tracer {sup 137}Cs after accidental releases. For that reason, two horizontal resolutions were deployed and used in the model, a regular grid of 2.5 x 1.27 , and the same grid stretched over Europe to reach a resolution of 0.66 x 0.51 . The vertical dimension is represented with two different resolutions, 19 and 39 levels respectively, extending up to the mesopause. Four different simulations are presented in this work; the first uses the regular grid over 19 vertical levels assuming that the emissions took place at the surface (RG19L(S)), the second also uses the regular grid over 19 vertical levels but realistic source injection heights (RG19L); in the third resolution the grid is regular and the vertical resolution 39 levels (RG39L) and finally, it is extended to the stretched grid with 19 vertical levels (Z19L). The model is validated with the Chernobyl accident which occurred in Ukraine (ex-USSR) on 26 May 1986 using the emission inventory from Brandt et al. (2002). This accident has been widely studied since 1986, and a large database has been created containing measurements of atmospheric activity concentration and total cumulative deposition for {sup 137}Cs from most of the European countries. According to the results, the performance of the model to predict the transport and deposition of the radioactive tracer was efficient and accurate presenting low biases in activity concentrations and deposition inventories, despite the large uncertainties on the intensity of the source released. The best agreement with observations was obtained using the highest horizontal resolution of the model (Z19L run). The model managed to predict the radioactive contamination in most of the European regions (similar to De Cort et al., 1998), and also the arrival times of the radioactive fallout. As regards to the vertical resolution, the largest biases were obtained

  17. Simulations of the transport and deposition of 137Cs over Europe after the Chernobyl Nuclear Power Plant accident: influence of varying emission-altitude and model horizontal and vertical resolution

    Science.gov (United States)

    Evangeliou, N.; Balkanski, Y.; Cozic, A.; Møller, A. P.

    2013-07-01

    The coupled model LMDZORINCA has been used to simulate the transport, wet and dry deposition of the radioactive tracer 137Cs after accidental releases. For that reason, two horizontal resolutions were deployed and used in the model, a regular grid of 2.5° × 1.27°, and the same grid stretched over Europe to reach a resolution of 0.66° × 0.51°. The vertical dimension is represented with two different resolutions, 19 and 39 levels respectively, extending up to the mesopause. Four different simulations are presented in this work; the first uses the regular grid over 19 vertical levels assuming that the emissions took place at the surface (RG19L(S)), the second also uses the regular grid over 19 vertical levels but realistic source injection heights (RG19L); in the third resolution the grid is regular and the vertical resolution 39 levels (RG39L) and finally, it is extended to the stretched grid with 19 vertical levels (Z19L). The model is validated with the Chernobyl accident which occurred in Ukraine (ex-USSR) on 26 May 1986 using the emission inventory from Brandt et al. (2002). This accident has been widely studied since 1986, and a large database has been created containing measurements of atmospheric activity concentration and total cumulative deposition for 137Cs from most of the European countries. According to the results, the performance of the model to predict the transport and deposition of the radioactive tracer was efficient and accurate presenting low biases in activity concentrations and deposition inventories, despite the large uncertainties on the intensity of the source released. The best agreement with observations was obtained using the highest horizontal resolution of the model (Z19L run). The model managed to predict the radioactive contamination in most of the European regions (similar to De Cort et al., 1998), and also the arrival times of the radioactive fallout. As regards to the vertical resolution, the largest biases were obtained for

  18. Capital and interest in horizontal innovation models

    OpenAIRE

    Man-Seop Park

    2010-01-01

    Horizontal innovation models have a common structure of three sequentially connected sectors. This structure--production of commodities by means of commodities--necessitates the compounding of interest on an input that goes through multiple production periods before the final good is produced. I argue that this aspect is missed (or deliberately assumed away) in typical horizontal innovation models and that this practice generates internal inconsistency in relation to the long run nature of th...

  19. Impact of horizontal resolution on prediction of tropical cyclones over ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    great importance. During the last two decades, there have been considerable improvements in the prediction of tropical cyclones by numerical models. High res- ... focus is on the use of high-resolution hydro- .... Verification analysis and forecast of mean sea level pressure (all at 00 UTC); (a) analysis on 9th Nov.'95,.

  20. Techniques for studying gravity waves and turbulence: Horizontal, vertical and temporal resolution needed

    Science.gov (United States)

    Avery, S. K.; Carter, D. A.

    1983-01-01

    One of the most important atmospheric measurements that is needed is a measure of the gravity-wave spectrum. The MST radar has been investigated as means to measure the temporal resolution required to determine gravity-wave oscillations. The required vertical and horizontal resolution is dependent on the particular part of the gravity wave spectrum that is analyzed. Horizontal spacing is also discussed.

  1. Parametric study for horizontal steam generator modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ovtcharova, I. [Energoproekt, Sofia (Bulgaria)

    1995-12-31

    In the presentation some of the calculated results of horizontal steam generator PGV - 440 modelling with RELAP5/Mod3 are described. Two nodalization schemes have been used with different components in the steam dome. A study of parameters variation on the steam generator work and calculated results is made in cases with separator and branch.

  2. Modelling Nitrogen Transformation in Horizontal Subsurface Flow ...

    African Journals Online (AJOL)

    A mathematical model was developed to permit dynamic simulation of nitrogen interaction in a pilot horizontal subsurface flow constructed wetland receiving effluents from primary facultative pond. The system was planted with Phragmites mauritianus, which was provided with root zone depth of 75 cm. The root zone was ...

  3. Effects of horizontal grid resolution on evapotranspiration partitioning using TerrSysMP

    Science.gov (United States)

    Shrestha, P.; Sulis, M.; Simmer, C.; Kollet, S.

    2018-02-01

    Biotic leaf transpiration (T) and abiotic evaporation (E) are the two major pathways by which water is transferred from land surfaces to the atmosphere. Earth system models simulating the terrestrial water, carbon and energy cycle are required to reliably embed the role of soil and vegetation processes in order to realistically reproduce both fluxes including their relative contributions to total evapotranspiration (ET). Earth system models are also being used with increasing spatial resolutions to better simulate the effects of surface heterogeneity on the regional water and energy cycle and to realistically include effects of subsurface lateral flow paths, which are expected to feed back on the exchange fluxes and their partitioning in the model. Using the hydrological component of the Terrestrial Systems Modeling Platform (TerrSysMP), we examine the uncertainty in the estimates of T/ET ratio due to horizontal model grid resolution for a dry and wet year in the Inde catchment (western Germany). The aggregation of topography results in smoothing of slope magnitudes and the filtering of small-scale convergence and divergence zones, which directly impacts the surface-subsurface flow. Coarsening of the grid resolution from 120 m to 960 m increased the available soil moisture for ground evaporation, and decreased T/ET ratio by about 5% and 8% for dry and wet year respectively. The change in T/ET ratio was more pronounced for agricultural crops compared to forested areas, indicating a strong local control of vegetation on the ground evaporation, affecting the domain average statistics.

  4. Modelling the horizontal steam generator with APROS

    Energy Technology Data Exchange (ETDEWEB)

    Ylijoki, J. [VTT Energy, Espoo (Finland); Palsinajaervi, C.; Porkholm, K. [IVO International Ltd, Vantaa (Finland)

    1995-12-31

    In this paper the capability of the five- and six-equation models of the simulation code APROS to simulate the behaviour of the horizontal steam generator is discussed. Different nodalizations are used in the modelling and the results of the stationary state runs are compared. Exactly the same nodalizations have been created for the five- and six-equation models. The main simulation results studied in this paper are void fraction and mass flow distributions in the secondary side of the steam generator. It was found that quite a large number of simulation volumes is required to simulate the distributions with a reasonable accuracy. The simulation results of the different models are presented and their validity is discussed. (orig.). 4 refs.

  5. Extreme scaling for global weather forecasts at O(1km) horizontal resolution

    Science.gov (United States)

    Wedi, Nils; Düben, Peter

    2017-04-01

    We report on recent experimentation towards improved scalability of high resolution simulations with the Integrated Forecast System of the European Centre for Medium-Range Weather Forecasts (ECMWF). A significant step towards further savings both in terms of throughput and speed-up is provided by the impact on simulations if numerical precision is selectively reduced in high resolution simulations from double to single precision. However, while higher horizontal resolution evidently increases the cost of simulations, there are other computational cost drivers arising from increasing model complexity through coupling of ocean waves, and including the ocean circulation and its interaction with the atmosphere. The cost/benefit ratios of these different modelling aspects are evaluated and illustrated with global simulations for the "Medicane" Trixie, a rare, high-impact weather event in the Mediterranean with a tropical-like cyclone structure that was observed in October/November 2016. High resolution simulations with IFS are performed as part of the ESiWACE project (www.esiwace.eu).

  6. MIPAS-ENVISAT limb-sounding measurements: trade-off study for improvement of horizontal resolution.

    Science.gov (United States)

    Ridolfi, Marco; Magnani, Luca; Carlotti, Massimo; Dinelli, Bianca Maria

    2004-11-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a limb-scanning spectrometer that has operated onboard the Environmental Satellite since the end of March 2002. Common features of limb-scanning experiments are both high vertical resolution and poor horizontal resolution. We exploit the two-dimensional geo-fit retrieval approach [Appl. Opt. 40, 1872-1875 (2001)] to investigate the possibility of improving the horizontal resolution of MIPAS measurements. Two different strategies are considered for this purpose, one exploiting the possibility (offered by the geo-fit analysis method) for an arbitrary definition of the retrieval grid, the other based on the possibility of saving measurement time by degrading the spectral resolution of the interferometer. The performances of the two strategies are compared in terms of the trade-off between the attained horizontal resolution and the retrieval precision. We find that for ozone it is possible to improve by a factor of 2 the horizontal resolution, which in the nominal measurement plan is approximately 530 km. This improvement corresponds to a degradation of the retrieval precision, which on average varies from a factor of 1.4 to 2.5, depending on the adopted spectral resolution.

  7. Sensitivity of RegCM3 simulations to horizontal resolution

    CSIR Research Space (South Africa)

    Bopape, Mary-Jane M

    2009-09-01

    Full Text Available Dynamic downscaling for climate studies utilises a regional climate model that is nested within a global climate model (GCM) or global reanalyses. The GCM or global reanalyses data is interpolated to the RCM's grid and used to drive the RCM...

  8. Climatological features of stratospheric streamers in the FUB-CMAM with increased horizontal resolution

    Directory of Open Access Journals (Sweden)

    K. Krüger

    2005-01-01

    Full Text Available The purpose of this study is to investigate horizontal transport processes in the winter stratosphere using data with a resolution relevant for chemistry and climate modeling. For this reason the Freie Universität Berlin Climate Middle Atmosphere Model (FUB-CMAM with its model top at 83 km altitude, increased horizontal resolution T42 and the semi-Lagrangian transport scheme for advecting passive tracers is used. A new approach of this paper is the classification of specific transport phenomena within the stratosphere into tropical-subtropical streamers (e.g. Offermann et al., 1999 and polar vortex extrusions hereafter called polar vortex streamers. To investigate the role played by these large-scale structures on the inter-annual and seasonal variability of transport processes in northern mid-latitudes, the global occurrence of such streamers was calculated based on a 10-year model climatology, concentrating on the existence of the Arctic polar vortex. For the identification and counting of streamers, the new method of zonal anomaly was chosen. The analysis of the months October-May yielded a maximum occurrence of tropical-subtropical streamers during Arctic winter and spring in the middle and upper stratosphere. Synoptic maps revealed highest intensities in the subtropics over East Asia with a secondary maximum over the Atlantic in the northern hemisphere. Furthermore, tropical-subtropical streamers exhibited a higher occurrence than polar vortex streamers, indicating that the subtropical barrier is more permeable than the polar vortex barrier (edge in the model, which is in good correspondence with observations (e.g. Plumb, 2002; Neu et al., 2003. Interesting for the total ozone decrease in mid-latitudes is the consideration of the lower stratosphere for tropical-subtropical streamers and the stratosphere above ~20 km altitude for polar vortex streamers, where strongest ozone depletion is observed at polar latitudes (WMO, 2003. In the

  9. Cuttings Transport Models and Experimental Visualization of Underbalanced Horizontal Drilling

    Directory of Open Access Journals (Sweden)

    Na Wei

    2013-01-01

    Full Text Available Aerated underbalanced horizontal drilling technology has become the focus of the drilling industry at home and abroad, and one of the engineering core issues is the horizontal borehole cleaning. Therefore, calculating the minimum injection volume of gas and liquid accurately is essential for the construction in aerated underbalanced horizontal drilling. This paper establishes a physical model of carrying cuttings and borehole cleaning in wellbore of horizontal well and a critical transport mathematical model according to gas-liquid-solid flow mechanism and large plane dunes particle transport theory.

  10. A modified calculation model for groundwater flowing to horizontal ...

    Indian Academy of Sciences (India)

    well pipe and aquifer couples the turbulent flow inside the horizontal seepage well with laminar flow in the aquifer. .... In the well pipe, the relationship between hydraulic head loss and flow velocity .... the steady-state mathematic model is developed for groundwater flowing to the horizontal seepage well under a river valley.

  11. Security camera resolution measurements: Horizontal TV lines versus modulation transfer function measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Birch, Gabriel Carisle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Griffin, John Clark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    The horizontal television lines (HTVL) metric has been the primary quantity used by division 6000 related to camera resolution for high consequence security systems. This document shows HTVL measurements are fundamen- tally insufficient as a metric to determine camera resolution, and propose a quantitative, standards based methodology by measuring the camera system modulation transfer function (MTF), the most common and accepted metric of res- olution in the optical science community. Because HTVL calculations are easily misinterpreted or poorly defined, we present several scenarios in which HTVL is frequently reported, and discuss their problems. The MTF metric is discussed, and scenarios are presented with calculations showing the application of such a metric.

  12. Condensation of steam in horizontal pipes: model development and validation

    International Nuclear Information System (INIS)

    Szijarto, R.

    2015-01-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich presents the development and validation of a model for the condensation of steam in horizontal pipes. Condensation models were introduced and developed particularly for the application in the emergency cooling system of a Gen-III+ boiling water reactor. Such an emergency cooling system consists of slightly inclined horizontal pipes, which are immersed in a cold water tank. The pipes are connected to the reactor pressure vessel. They are responsible for a fast depressurization of the reactor core in the case of accident. Condensation in horizontal pipes was investigated with both one-dimensional system codes (RELAP5) and three-dimensional computational fluid dynamics software (ANSYS FLUENT). The performance of the RELAP5 code was not sufficient for transient condensation processes. Therefore, a mechanistic model was developed and implemented. Four models were tested on the LAOKOON facility, which analysed direct contact condensation in a horizontal duct

  13. A modified calculation model for groundwater flowing to horizontal ...

    Indian Academy of Sciences (India)

    The simulation models for groundwater flowing to horizontal seepage wells proposed by Wang and Zhang (2007) are based on the theory of coupled seepage-pipe flow model which treats the well pipe as a highly permeable medium. However, the limitations of the existing model were found during applications. Specifically ...

  14. A model of strategic marketing alliances for hospices: horizontal alliances.

    Science.gov (United States)

    Self, D R; Starnes, B J

    1999-01-01

    This article develops two previous research efforts. William J. Winston (1994, 1995) has proposed a set of strategies by which health care organizations can benefit from forging strategic alliances. Raadt and Self (1997) have proposed a classification model of alliances including horizontal, vertical, internal and osmotic. In the first of two articles, this paper presents a model of horizontal alliances. The subsets include transregional, service mergers, networks, venture capital investments, trade and professional organizations, and promotional alliances. Advantages and disadvantages of each are discussed.

  15. Models for prediction of global solar radiation on horizontal surface ...

    African Journals Online (AJOL)

    The estimation of global solar radiation continues to play a fundamental role in solar engineering systems and applications. This paper compares various models for estimating the average monthly global solar radiation on horizontal surface for Akure, Nigeria, using solar radiation and sunshine duration data covering years ...

  16. Numerical modeling of secondary side thermohydraulics of horizontal steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Melikhov, V.I.; Melikhov, O.I.; Nigmatulin, B.I. [Research and Engineering Centre of LWR Nuclear Plants Safety, Moscow (Russian Federation)

    1995-12-31

    A mathematical model for the transient three-dimensional secondary side thermal hydraulics of the horizontal steam generator has been developed. The calculations of the steam generator PGV-1000 and PGV-4 nominal regimes and comparison of numerical and experimental results have been carried out. 7 refs.

  17. Cosmological implication of massive neutrinos in a horizontal model context

    International Nuclear Information System (INIS)

    Goldman, C.

    1985-04-01

    An extended version of the Glashow-Weinberg-Salam model for the eletroweak interactions is studied in detail. It has an extra global horizontal symmetry, which allows the appearance of neutrino mass terms. The constraints imposed by the standard cosmological model were used to determine the allowed range of variations of the free parameters of this model. As applications, the solar neutrinos problem and the formation of large scale structures in the universe is studied. (Author) [pt

  18. Improving Arctic sea ice edge forecasts by assimilating high horizontal resolution sea ice concentration data into the US Navy's ice forecast systems

    Science.gov (United States)

    Posey, P. G.; Metzger, E. J.; Wallcraft, A. J.; Hebert, D. A.; Allard, R. A.; Smedstad, O. M.; Phelps, M. W.; Fetterer, F.; Stewart, J. S.; Meier, W. N.; Helfrich, S. R.

    2015-08-01

    This study presents the improvement in ice edge error within the US Navy's operational sea ice forecast systems gained by assimilating high horizontal resolution satellite-derived ice concentration products. Since the late 1980's, the ice forecast systems have assimilated near real-time sea ice concentration derived from the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSMI and then SSMIS). The resolution of the satellite-derived product was approximately the same as the previous operational ice forecast system (25 km). As the sea ice forecast model resolution increased over time, the need for higher horizontal resolution observational data grew. In 2013, a new Navy sea ice forecast system (Arctic Cap Nowcast/Forecast System - ACNFS) went into operations with a horizontal resolution of ~ 3.5 km at the North Pole. A method of blending ice concentration observations from the Advanced Microwave Scanning Radiometer (AMSR2) along with a sea ice mask produced by the National Ice Center (NIC) has been developed, resulting in an ice concentration product with very high spatial resolution. In this study, ACNFS was initialized with this newly developed high resolution blended ice concentration product. The daily ice edge locations from model hindcast simulations were compared against independent observed ice edge locations. ACNFS initialized using the high resolution blended ice concentration data product decreased predicted ice edge location error compared to the operational system that only assimilated SSMIS data. A second evaluation assimilating the new blended sea ice concentration product into the pre-operational Navy Global Ocean Forecast System 3.1 also showed a substantial improvement in ice edge location over a system using the SSMIS sea ice concentration product alone. This paper describes the technique used to create the blended sea ice concentration product and the significant improvements in ice edge forecasting in both of the

  19. Numerical Modelling of the Mining Induced Horizontal Displacement

    Directory of Open Access Journals (Sweden)

    Tajduś Krzysztof

    2015-12-01

    Full Text Available The paper presents results of numerical calculations and modeling of mining-induced surface deformation based on Finite Element Method (FEM. Applying the numerical method discussed to calculations allows us to assume a larger number of factors, such as rock mass structure, fracture network, rock properties, etc., which essentially affect the results obtained. On the basis of an elastic transversely isotropic model, an analysis of horizontal displacement distribution and surface subsidence was carried out for two sample regions of mines. The results of numerical calculations were later compared with the measured values. Such an analysis proved that the applied numerical model properly described distribution and values of subsidence and slope of subsidence trough, though there were serious differences in the values of calculated horizontal displacement, especially in areas of far influence range. In order to improve the matching, the influence of boundary conditions of the model on the value of calculated horizontal displacement was analyzed. The results are presented in graphs.

  20. Experimental consequences of a horizontal gauge model for CP nonconservation

    International Nuclear Information System (INIS)

    Hou, W.; Soni, A.

    1985-01-01

    The experimental consequences of a model that links CP nonconservation with horizontal interactions and is based on the gauge group SU/sub l//sup W/(2) x SU/sub R//sup H/(2) x U/sup Y/ (1) are investigated. The magnitude of the observed CP nonconservation and that of the K/sub L/-K/sub S/ mass difference constrains the horizontal gauge boson masses (M/sub s/crR) such that 66 TeV> or approx. =M/sub s/crR>5 TeV. The model implies an extremely small value for Vertical Barepsilon'/epsilonVertical Bar. The branching ratio for K/sub L/→μe (K→πμe) could be greater than roughly-equal10 -10 (approx.10 -12 ). theta/sub QFD/ vanishes at the tree level. The contribution from the gauge sector, arising at two loops, is also discussed

  1. Modelling studies of horizontal steam generator PGV-1000 with Cathare

    Energy Technology Data Exchange (ETDEWEB)

    Karppinen, I. [VTT Energy, Espoo (Finland)

    1995-12-31

    To perform thermal-hydraulic studies applied to nuclear power plants equipped with VVER, a program of qualification and assessment of the CATHARE computer code is in progress at the Institute of Protection and Nuclear Safety (IPSN). In this paper studies of modelling horizontal steam generator of VVER-1000 with the CATHARE computer code are presented. Steady state results are compared with measured data from the fifth unit of Novovoronezh nuclear power plant. (orig.). 10 refs.

  2. Field Red Horizontal Branch Star Chemical Compositions from High Resolution Infrared Spectra

    Science.gov (United States)

    Sneden, Chris; Afsar, Melike; Bozkurt, Zeynep; Bocek-Topcu, Gamze; Mace, Gregory N.; Kim, Hwihyun; Kaplan, Kyle; Kidder, Benjamin; McLane, Jacob

    2017-06-01

    We have observed three field red horizontal branch stars with the Immersion Grating Infrared Spectrograph (IGRINS). The high resolution (R~45000) high signal-to-noise (S/N > 200) spectra obtained with IGRINS cover the complete H-band (1.50-1.80 micron) and K-band (1.90-2.45 micron). We analyzed hundreds of lines of the ubiquitous OH, CN, and CO molecular bands, and found more than 80 lines of atomic species that were useful for abundance work. A combination of good laboratory transition probabilities (when available) and ones derived from reverse solar analyses were employed. Our transition data were checked through studies of the Arcturus Atlas spectrum. We derived abundances from synthetic spectra instead of from equivalent widths. With IGRINS data we were able to extract metallicities and abundance ratios for more than 20 elements, including several not detectable or poorly represented in optical wavelength regions. Our abundances from IGRINS spectra are in excellent accord with those derived from optical spectrum studies. These results are directly applicable to calibrations of results from lower-resolution and/or S/N infrared spectral surveys. IGRINS observations will give high reolution spectroscopic access to heavily obscured normal red giants and other cool stars with unusual element mixes.This work used the Immersion Grating Infrared Spectrograph (IGRINS) that was developed under a collaboration between the University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI) with the financial support of the US National Science Foundation (NSF; grant AST-1229522), of the University of Texas at Austin, and of the Korean GMT Project of KASI. Our project also has been supported by NSF grants AST~1211585 and AST~1616040, by the University of Texas Rex G. Baker, Jr. Centennial Research Endowment, and by The Scientific and Technological Research Council of Turkey (TUBITAK, project No. 112T929).

  3. a Variable Resolution Global Spectral Model.

    Science.gov (United States)

    Hardiker, Vivek Manohar

    A conformal transformation suggested by F. Schimdt is followed to implement a global spectral model with variable horizontal resolution. A conformal mapping is defined between the real physical sphere (Earth) to a transformed (Computational) sphere. The model equations are discretized on the computational sphere and the conventional spectral technique is applied to solve the model equations. There are two types of transformations used in the present study, namely, the Stretching transformation and the Rotation of the horizontal grid points. Application of the stretching transformation results in finer resolution along the meridional direction. The stretching is controlled by a parameter C. The rotation transformation can be used to relocate the North Pole of the model to any point on the geographic sphere. The idea is now to rotate the pole to the area of interest and refine the resolution around the new pole by applying the stretching transformation. The stretching transformation can be applied alone without the rotation. A T-42 Spectral Shallow-Water model is transformed by applying the stretching transformation alone as well as the two transformations together. A T-42 conventional Spectral Shallow-Water model is run as the control experiment and a conventional T-85 Spectral Shallow-Water model run is treated as the benchmark (Truth) solution. RMS error analysis for the geopotential field as well as the wind field is performed to evaluate the forecast made by the transformed model. It is observed that the RMS error of the transformed model is lower than that of the control run in a latitude band, for the case of stretching transformation alone, while for the total transformation (rotation followed by stretching), similar results are obtained for a rectangular domain. A multi-level global spectral model is designed from the current FSU global spectral model in order to implement the conformal transformation. The transformed T-85 model is used to study Hurricane

  4. Global horizontal irradiance clear sky models : implementation and analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua S.; Hansen, Clifford W.; Reno, Matthew J.

    2012-03-01

    Clear sky models estimate the terrestrial solar radiation under a cloudless sky as a function of the solar elevation angle, site altitude, aerosol concentration, water vapor, and various atmospheric conditions. This report provides an overview of a number of global horizontal irradiance (GHI) clear sky models from very simple to complex. Validation of clear-sky models requires comparison of model results to measured irradiance during clear-sky periods. To facilitate validation, we present a new algorithm for automatically identifying clear-sky periods in a time series of GHI measurements. We evaluate the performance of selected clear-sky models using measured data from 30 different sites, totaling about 300 site-years of data. We analyze the variation of these errors across time and location. In terms of error averaged over all locations and times, we found that complex models that correctly account for all the atmospheric parameters are slightly more accurate than other models, but, primarily at low elevations, comparable accuracy can be obtained from some simpler models. However, simpler models often exhibit errors that vary with time of day and season, whereas the errors for complex models vary less over time.

  5. Hyper-Resolution Groundwater Modeling using MODFLOW 6

    Science.gov (United States)

    Hughes, J. D.; Langevin, C.

    2017-12-01

    MODFLOW 6 is the latest version of the U.S. Geological Survey's modular hydrologic model. MODFLOW 6 was developed to synthesize many of the recent versions of MODFLOW into a single program, improve the way different process models are coupled, and to provide an object-oriented framework for adding new types of models and packages. The object-oriented framework and underlying numerical solver make it possible to tightly couple any number of hyper-resolution models within coarser regional models. The hyper-resolution models can be used to evaluate local-scale groundwater issues that may be affected by regional-scale forcings. In MODFLOW 6, hyper-resolution meshes can be maintained as separate model datasets, similar to MODFLOW-LGR, which simplifies the development of a coarse regional model with imbedded hyper-resolution models from a coarse regional model. For example, the South Atlantic Coastal Plain regional water availability model was converted from a MODFLOW-2000 model to a MODFLOW 6 model. The horizontal discretization of the original model is approximately 3,218 m x 3,218 m. Hyper-resolution models of the Aiken and Sumter County water budget areas in South Carolina with a horizontal discretization of approximately 322 m x 322 m were developed and were tightly coupled to a modified version of the original coarse regional model that excluded these areas. Hydraulic property and aquifer geometry data from the coarse model were mapped to the hyper-resolution models. The discretization of the hyper-resolution models is fine enough to make detailed analyses of the effect that changes in groundwater withdrawals in the production aquifers have on the water table and surface-water/groundwater interactions. The approach used in this analysis could be applied to other regional water availability models that have been developed by the U.S. Geological Survey to evaluate local scale groundwater issues.

  6. Slag transport models for vertical and horizontal surfaces. [SLGTR code

    Energy Technology Data Exchange (ETDEWEB)

    Chow, L S.H.; Johnson, T R

    1978-01-01

    In a coal-fired MHD system, all downstream component surfaces that are exposed to combustion gases will be covered by a solid, liquid, or solid-liquid film of slag, seed, or a mixture of the two, the specific nature of the film depending on the physical properties of the slag and seed and on local conditions. An analysis was made of a partly-liquid slag film flowing on a cooled vertical or horizontal wall of a large duct, through which passed slag-laden combustion gases. The model is applicable to the high-temperature steam generators in the downstream system of an MHD power plant and was used in calculations for a radiant-boiler concept similar to that in the 1000-MWe Gilbert-STD Baseline Plant study and also for units large enough for 230 and 8 lb/s (104.3 and 3.5 kg/s) of combustion gas. The qualitative trends of the results are similar for both vertical and horizontal surfaces. The results show the effects of the slag film, slag properties, and gas emissivity on the heat flux to the steam tubes. The slag film does not reduce the rate of heat transfer in proportion to its surface temperature, because most of the heat is radiated from the gas and particles suspended in it to the slag surface.

  7. Horizontal soil water potential heterogeneity: simplifying approaches for crop water dynamics models

    Science.gov (United States)

    Couvreur, V.; Vanderborght, J.; Beff, L.; Javaux, M.

    2014-05-01

    Soil water potential (SWP) is known to affect plant water status, and even though observations demonstrate that SWP distribution around roots may limit plant water availability, its horizontal heterogeneity within the root zone is often neglected in hydrological models. As motive, using a horizontal discretisation significantly larger than one centimetre is often essential for computing time considerations, especially for large-scale hydrodynamics models. In this paper, we simulate soil and root system hydrodynamics at the centimetre scale and evaluate approaches to upscale variables and parameters related to root water uptake (RWU) for two crop systems: a densely seeded crop with an average uniform distribution of roots in the horizontal direction (winter wheat) and a wide-row crop with lateral variations in root density (maize). In a first approach, the upscaled water potential at soil-root interfaces was assumed to equal the bulk SWP of the upscaled soil element. Using this assumption, the 3-D high-resolution model could be accurately upscaled to a 2-D model for maize and a 1-D model for wheat. The accuracy of the upscaled models generally increased with soil hydraulic conductivity, lateral homogeneity of root distribution, and low transpiration rate. The link between horizontal upscaling and an implicit assumption on soil water redistribution was demonstrated in quantitative terms, and explained upscaling accuracy. In a second approach, the soil-root interface water potential was estimated by using a constant rate analytical solution of the axisymmetric soil water flow towards individual roots. In addition to the theoretical model properties, effective properties were tested in order to account for unfulfilled assumptions of the analytical solution: non-uniform lateral root distributions and transient RWU rates. Significant improvements were however only noticed for winter wheat, for which the first approach was already satisfying. This study confirms that the

  8. Computational modeling of the nonlinear stochastic dynamics of horizontal drillstrings

    Science.gov (United States)

    Cunha, Americo; Soize, Christian; Sampaio, Rubens

    2015-11-01

    This work intends to analyze the nonlinear stochastic dynamics of drillstrings in horizontal configuration. For this purpose, it considers a beam theory, with effects of rotatory inertia and shear deformation, which is capable of reproducing the large displacements that the beam undergoes. The friction and shock effects, due to beam/borehole wall transversal impacts, as well as the force and torque induced by bit-rock interaction, are also considered in the model. Uncertainties of bit-rock interaction model are taken into account using a parametric probabilistic approach. Numerical simulations have shown that the mechanical system of interest has a very rich nonlinear stochastic dynamics, which generate phenomena such as bit-bounce, stick-slip, and transverse impacts. A study aiming to maximize the drilling process efficiency, varying drillstring velocities of translation and rotation is presented. Also, the work presents the definition and solution of two optimizations problems, one deterministic and one robust, where the objective is to maximize drillstring rate of penetration into the soil respecting its structural limits.

  9. High resolution reservoir geological modelling using outcrop information

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Changmin; Lin Kexiang; Liu Huaibo [Jianghan Petroleum Institute, Hubei (China)] [and others

    1997-08-01

    This is China`s first case study of high resolution reservoir geological modelling using outcrop information. The key of the modelling process is to build a prototype model and using the model as a geological knowledge bank. Outcrop information used in geological modelling including seven aspects: (1) Determining the reservoir framework pattern by sedimentary depositional system and facies analysis; (2) Horizontal correlation based on the lower and higher stand duration of the paleo-lake level; (3) Determining the model`s direction based on the paleocurrent statistics; (4) Estimating the sandbody communication by photomosaic and profiles; (6) Estimating reservoir properties distribution within sandbody by lithofacies analysis; and (7) Building the reservoir model in sandbody scale by architectural element analysis and 3-D sampling. A high resolution reservoir geological model of Youshashan oil field has been built by using this method.

  10. The problem of multicollinearity in horizontal solar radiation estimation models and a new model for Turkey

    International Nuclear Information System (INIS)

    Demirhan, Haydar

    2014-01-01

    Highlights: • Impacts of multicollinearity on solar radiation estimation models are discussed. • Accuracy of existing empirical models for Turkey is evaluated. • A new non-linear model for the estimation of average daily horizontal global solar radiation is proposed. • Estimation and prediction performance of the proposed and existing models are compared. - Abstract: Due to the considerable decrease in energy resources and increasing energy demand, solar energy is an appealing field of investment and research. There are various modelling strategies and particular models for the estimation of the amount of solar radiation reaching at a particular point over the Earth. In this article, global solar radiation estimation models are taken into account. To emphasize severity of multicollinearity problem in solar radiation estimation models, some of the models developed for Turkey are revisited. It is observed that these models have been identified as accurate under certain multicollinearity structures, and when the multicollinearity is eliminated, the accuracy of these models is controversial. Thus, a reliable model that does not suffer from multicollinearity and gives precise estimates of global solar radiation for the whole region of Turkey is necessary. A new nonlinear model for the estimation of average daily horizontal solar radiation is proposed making use of the genetic programming technique. There is no multicollinearity problem in the new model, and its estimation accuracy is better than the revisited models in terms of numerous statistical performance measures. According to the proposed model, temperature, precipitation, altitude, longitude, and monthly average daily extraterrestrial horizontal solar radiation have significant effect on the average daily global horizontal solar radiation. Relative humidity and soil temperature are not included in the model due to their high correlation with precipitation and temperature, respectively. While altitude has

  11. Resolution of thermal striping issue downstream of a horizontal pipe elbow in stratified pipe flow

    International Nuclear Information System (INIS)

    Kuzay, T.M.; Kasza, K.E.

    1985-01-01

    A thermally stratified pipe flow produced by a thermal transient when passing through a horizontal elbow as a result of secondary flow gives rise to large thermal fluctuations on the inner curvature wall of the downstream piping. These fluctuations were measured in a specially instrumented horizontal pipe and elbow system on a test set-up using water in the Mixing Components Technology Facility (MCTF) at Argonne National Laboratory (ANL). This study is part of a larger program which is studying the influence of thermal buoyancy on general reactor component performance. This paper discusses the influence of pipe flow generated thermal oscillations on the thermal stresses induced in the pipe walls. The instrumentation was concentrated around the exit plane of the 90 0 sweep elbow, since prior tests had indicated that the largest thermal fluctuations would occur within about one hydraulic diameter downstream of the elbow exit. The thermocouples were located along the inner curvature of the piping and measured the near surface fluid temperature. The test matrix involved thermal downramps under turbulent flow conditions

  12. Synthetic horizontal branch models for globular clusters - the luminosity of the horizontal branch and the Oosterhoff effect

    International Nuclear Information System (INIS)

    Lee, Y.W.; Demarque, P.; Zinn, R.

    1987-01-01

    The variation of horizontal-branch (HB) luminosities with metal abundances is analyzed on the basis of HB models synthesized from theoretical HB evolutionary tracks. The focus is on the Oosterhoff effect, as related to period shifts in globular-cluster RR Lyr variables. The construction of the models and the Oosterhoff period groups is explained in detail, and the implications for globular-cluster ages are considered. The ratio of Delta M(bol) (RR) to Delta Fe/H for the HB is calculated as 0.24, slightly steeper than that found by Sandage (1981 and 1982). 35 references

  13. ALCAR - A Model for Horizontal R&D Consortia

    Energy Technology Data Exchange (ETDEWEB)

    Barthold, G.B.; Das, S.K.; Hayden, H.W.

    1999-03-01

    The ALCARTM Consortium was created to develop a low cost, non-heat treatable automotive body sheet alloy. This paper will discuss the management aspects of organizing and running a horizontal consortium for competing companies to cooperate in conducting pre-competitive research and development involving the US Department of Energy, National Laboratories, Universities and industrial consultants.

  14. Influence of Regional Climate Model spatial resolution on wind climates

    Science.gov (United States)

    Pryor, S. C.; Barthelmie, R. J.; Nikulin, G.; Jones, C.

    2010-12-01

    Global and regional climate models are being run at increasingly fine horizontal and vertical resolution with the goal of increased skill. However, relatively few studies have quantified the change in modeled wind climates that derives from applying a Regional Climate Model (RCM) at varying resolutions, and the response to varying resolution may be highly non-linear since most models run in climate mode are hydrostatic. Thus, herein we examine the influence of grid-resolution on modelled wind speeds and gusts and derived extremes thereof over southern Scandinavia using output from the Rossby Centre (RCA3) RCM run at four different resolutions from 50 x 50 km to 6 x 6 km, and with two different vertical grid-spacings. Domain averaged fifty-year return period wind speeds and wind gusts derived using the method of moments approach to compute the Gumbel parameters, increase with resolution (Table 1), though the change is strongly mediated by the model grid-cell surface characteristics. Power spectra of the 3-hourly model time-step ‘instantaneous’ wind speeds and daily wind gusts at all four resolutions show clear peaks in the variance associated with bi-annual, annual, seasonal and synoptic frequencies. The variance associated with these peaks is enhanced with increased resolution, though not in a monotonic fashion, and is more marked in wind gusts than wind speeds. Relative to in situ observations, the model generally underestimates the variance, particularly associated with the synoptic time scale, even for the highest resolution simulations. There is some evidence to suggest that the change in the power spectra with horizontal resolution is less marked in the transition from 12.5 km to 6.25 km, than from 50 to 25 km, or 25 km to 12.5 km.Table 1. Domain averaged mean annual wind speed (U), 50-year return period extreme wind speed (U50yr) and wind gust (Gust50yr) (m/s) from the four RCA3 simulations at different resolution based on output from 1987-2008. The

  15. Modeling of leachate recirculation using combined drainage blanket-horizontal trench systems in bioreactor landfills.

    Science.gov (United States)

    Feng, Shi-Jin; Cao, Ben-Yi; Xie, Hai-Jian

    2017-10-01

    Leachate recirculation in municipal solid waste (MSW) landfills operated as bioreactors offers significant economic and environmental benefits. Combined drainage blanket (DB)-horizontal trench (HT) systems can be an alternative to single conventional recirculation approaches and can have competitive advantages. The key objectives of this study are to investigate combined drainage blanket -horizontal trench systems, to analyze the effects of applying two recirculation systems on the leachate migration in landfills, and to estimate some key design parameters (e.g., the steady-state flow rate, the influence width, and the cumulative leachate volume). It was determined that an effective recirculation model should consist of a moderate horizontal trench injection pressure head and supplementary leachate recirculated through drainage blanket, with an objective of increasing the horizontal unsaturated hydraulic conductivity and thereby allowing more leachate to flow from the horizontal trench system in a horizontal direction. In addition, design charts for engineering application were established using a dimensionless variable formulation.

  16. Allocating emissions to 4 km and 1 km horizontal spatial resolutions and its impact on simulated NOx and O3 in Houston, TX

    Science.gov (United States)

    Pan, Shuai; Choi, Yunsoo; Roy, Anirban; Jeon, Wonbae

    2017-09-01

    A WRF-SMOKE-CMAQ air quality modeling system was used to investigate the impact of horizontal spatial resolution on simulated nitrogen oxides (NOx) and ozone (O3) in the Greater Houston area (a non-attainment area for O3). We employed an approach recommended by the United States Environmental Protection Agency to allocate county-based emissions to model grid cells in 1 km and 4 km horizontal grid resolutions. The CMAQ Integrated Process Rate analyses showed a substantial difference in emissions contributions between 1 and 4 km grids but similar NOx and O3 concentrations over urban and industrial locations. For example, the peak NOx emissions at an industrial and urban site differed by a factor of 20 for the 1 km and 8 for the 4 km grid, but simulated NOx concentrations changed only by a factor of 1.2 in both cases. Hence, due to the interplay of the atmospheric processes, we cannot expect a similar level of reduction of the gas-phase air pollutants as the reduction of emissions. Both simulations reproduced the variability of NASA P-3B aircraft measurements of NOy and O3 in the lower atmosphere (from 90 m to 4.5 km). Both simulations provided similar reasonable predictions at surface, while 1 km case depicted more detailed features of emissions and concentrations in heavily polluted areas, such as highways, airports, and industrial regions, which are useful in understanding the major causes of O3 pollution in such regions, and to quantify transport of O3 to populated communities in urban areas. The Integrated Reaction Rate analyses indicated a distinctive difference of chemistry processes between the model surface layer and upper layers, implying that correcting the meteorological conditions at the surface may not help to enhance the O3 predictions. The model-observation O3 bias in our studies (e.g., large over-prediction during the nighttime or along Gulf of Mexico coastline), were due to uncertainties in meteorology, chemistry or other processes. Horizontal grid

  17. A novel super-resolution camera model

    Science.gov (United States)

    Shao, Xiaopeng; Wang, Yi; Xu, Jie; Wang, Lin; Liu, Fei; Luo, Qiuhua; Chen, Xiaodong; Bi, Xiangli

    2015-05-01

    Aiming to realize super resolution(SR) to single image and video reconstruction, a super resolution camera model is proposed for the problem that the resolution of the images obtained by traditional cameras behave comparatively low. To achieve this function we put a certain driving device such as piezoelectric ceramics in the camera. By controlling the driving device, a set of continuous low resolution(LR) images can be obtained and stored instantaneity, which reflect the randomness of the displacements and the real-time performance of the storage very well. The low resolution image sequences have different redundant information and some particular priori information, thus it is possible to restore super resolution image factually and effectively. The sample method is used to derive the reconstruction principle of super resolution, which analyzes the possible improvement degree of the resolution in theory. The super resolution algorithm based on learning is used to reconstruct single image and the variational Bayesian algorithm is simulated to reconstruct the low resolution images with random displacements, which models the unknown high resolution image, motion parameters and unknown model parameters in one hierarchical Bayesian framework. Utilizing sub-pixel registration method, a super resolution image of the scene can be reconstructed. The results of 16 images reconstruction show that this camera model can increase the image resolution to 2 times, obtaining images with higher resolution in currently available hardware levels.

  18. Is Convection Sensitive to Model Vertical Resolution and Why?

    Science.gov (United States)

    Xie, S.; Lin, W.; Zhang, G. J.

    2017-12-01

    Model sensitivity to horizontal resolutions has been studied extensively, whereas model sensitivity to vertical resolution is much less explored. In this study, we use the US Department of Energy (DOE)'s Accelerated Climate Modeling for Energy (ACME) atmosphere model to examine the sensitivity of clouds and precipitation to the increase of vertical resolution of the model. We attempt to understand what results in the behavior change (if any) of convective processes represented by the unified shallow and turbulent scheme named CLUBB (Cloud Layers Unified by Binormals) and the Zhang-McFarlane deep convection scheme in ACME. A short-term hindcast approach is used to isolate parameterization issues from the large-scale circulation. The analysis emphasizes on how the change of vertical resolution could affect precipitation partitioning between convective- and grid-scale as well as the vertical profiles of convection-related quantities such as temperature, humidity, clouds, convective heating and drying, and entrainment and detrainment. The goal is to provide physical insight into potential issues with model convective processes associated with the increase of model vertical resolution. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Horizontal Positional Accuracy of Google Earth’s High-Resolution Imagery Archive

    Directory of Open Access Journals (Sweden)

    David Potere

    2008-12-01

    Full Text Available Google Earth now hosts high-resolution imagery that spans twenty percent of the Earth’s landmass and more than a third of the human population. This contemporary highresolution archive represents a significant, rapidly expanding, cost-free and largely unexploited resource for scientific inquiry. To increase the scientific utility of this archive, we address horizontal positional accuracy (georegistration by comparing Google Earth with Landsat GeoCover scenes over a global sample of 436 control points located in 109 cities worldwide. Landsat GeoCover is an orthorectified product with known absolute positional accuracy of less than 50 meters root-mean-squared error (RMSE. Relative to Landsat GeoCover, the 436 Google Earth control points have a positional accuracy of 39.7 meters RMSE (error magnitudes range from 0.4 to 171.6 meters. The control points derived from satellite imagery have an accuracy of 22.8 meters RMSE, which is significantly more accurate than the 48 control-points based on aerial photography (41.3 meters RMSE; t-test p-value < 0.01. The accuracy of control points in more-developed countries is 24.1 meters RMSE, which is significantly more accurate than the control points in developing countries (44.4 meters RMSE; t-test p-value < 0.01. These findings indicate that Google Earth highresolution imagery has a horizontal positional accuracy that is sufficient for assessing moderate-resolution remote sensing products across most of the world’s peri-urban areas.

  20. High-resolution mass spectrometer with correction of horizontal and vertical aberrations

    International Nuclear Information System (INIS)

    Sachenko, V.D.; Fridlyanskij, G.V.

    1980-01-01

    Principles of calculation of the ion-optical system of a high-precision two-cascade sector type mass-spectrometer with total correction of spherical aberrations as well as the group of second order vertical aberrations are considered. A mass-spectrometer construction is described and some test results of the spectrometer are given. Configuration of boundaries of a spectrometer magnetic field has been formed by means of convex magnetic screens adjoining concave edqes of pole pieces. An energy diaphragm has been installed in the intermediate focus of the system. Precision slits of a source and receiver were made according to a spring parallelogram resolution of spectrometer constituted 80-100 thousands at a level of 10% of peak height. At a residual pressure of 5x10 -7 torr and 3-5x10 -5 torr inlet pressure in the source for Ar ''tail'' intensity in a neighbouring line amounted to 0.6x10 -6 of a main line. A measurement error for relative mass difference using the method of peak matching didnot exceed 1-2x10 -6

  1. High-resolution digital movies of emerging flux and horizontal flows in active regions on the sun

    Science.gov (United States)

    Topka, K.; Ferguson, S.; Frank, Z.; Tarbell, T.; Title, A.

    1988-01-01

    High-resolution observations of active regions in many wavelength bands obtained at the Vacuum Tower Telescope of NSO/Sunspot (Sacramento Peak) are presented. The SOUP tunable filter, HRSO 1024 x 1024 CCD camera, and a sunspot tracker for image stabilization were used. Subarrays of 512 x 512 pixels were processed digitally and recorded on videodisk in movie format. The movies with 0.5 to 1 arcsecond resolution of the following simultaneous observations were shown: green continuum, longitudinal magnetogram, Doppler velocity, Fe I 5576 A line center, H alpha wings, and H alpha line center. The best set of movies show a 90 x 90 arcsecond field-of-view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Flux emergence is most easily discovered in line center movies: an elongated dark feature appears first, followed soon after by bright points at one or both ends. A brief, strong upflow is seen when the dark feature first appears; downflow in the bright points persists much longer. The magnetic flux appears to increase gradually over this extended period. Some of the flux emergence events were studied in detail, with measurements of horizontal and vertical velocities and magnetic flux versus time within one footpoint of the loop.

  2. High-resolution digital movies of emerging flux and horizontal flows in active regions on the sun

    International Nuclear Information System (INIS)

    Topka, K.; Ferguson, S.; Frank, Z.; Tarbell, T.; Title, A.

    1988-01-01

    High-resolution observations of active regions in many wavelength bands obtained at the Vacuum Tower Telescope of NSO/Sunspot (Sacramento Peak) are presented. The SOUP tunable filter, HRSO 1024 x 1024 CCD camera, and a sunspot tracker for image stabilization were used. Subarrays of 512 x 512 pixels were processed digitally and recorded on videodisk in movie format. The movies with 0.5 to 1 arcsecond resolution of the following simultaneous observations were shown: green continuum, longitudinal magnetogram, Doppler velocity, Fe I 5576 A line center, H alpha wings, and H alpha line center. The best set of movies show a 90 x 90 arcsecond field-of-view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Flux emergence is most easily discovered in line center movies: an elongated dark feature appears first, followed soon after by bright points at one or both ends. A brief, strong upflow is seen when the dark feature first appears; downflow in the bright points persists much longer. The magnetic flux appears to increase gradually over this extended period. Some of the flux emergence events were studied in detail, with measurements of horizontal and vertical velocities and magnetic flux versus time within one footpoint of the loop

  3. A 4.5 km resolution Arctic Ocean simulation with the global multi-resolution model FESOM 1.4

    Science.gov (United States)

    Wang, Qiang; Wekerle, Claudia; Danilov, Sergey; Wang, Xuezhu; Jung, Thomas

    2018-04-01

    In the framework of developing a global modeling system which can facilitate modeling studies on Arctic Ocean and high- to midlatitude linkage, we evaluate the Arctic Ocean simulated by the multi-resolution Finite Element Sea ice-Ocean Model (FESOM). To explore the value of using high horizontal resolution for Arctic Ocean modeling, we use two global meshes differing in the horizontal resolution only in the Arctic Ocean (24 km vs. 4.5 km). The high resolution significantly improves the model's representation of the Arctic Ocean. The most pronounced improvement is in the Arctic intermediate layer, in terms of both Atlantic Water (AW) mean state and variability. The deepening and thickening bias of the AW layer, a common issue found in coarse-resolution simulations, is significantly alleviated by using higher resolution. The topographic steering of the AW is stronger and the seasonal and interannual temperature variability along the ocean bottom topography is enhanced in the high-resolution simulation. The high resolution also improves the ocean surface circulation, mainly through a better representation of the narrow straits in the Canadian Arctic Archipelago (CAA). The representation of CAA throughflow not only influences the release of water masses through the other gateways but also the circulation pathways inside the Arctic Ocean. However, the mean state and variability of Arctic freshwater content and the variability of freshwater transport through the Arctic gateways appear not to be very sensitive to the increase in resolution employed here. By highlighting the issues that are independent of model resolution, we address that other efforts including the improvement of parameterizations are still required.

  4. A meteorological distribution system for high-resolution terrestrial modeling (MicroMet)

    Science.gov (United States)

    Glen E. Liston; Kelly Elder

    2006-01-01

    An intermediate-complexity, quasi-physically based, meteorological model (MicroMet) has been developed to produce high-resolution (e.g., 30-m to 1-km horizontal grid increment) atmospheric forcings required to run spatially distributed terrestrial models over a wide variety of landscapes. The following eight variables, required to run most terrestrial models, are...

  5. Using High Spatial-resolution Regional Atmospheric Data for Computation of GRACE Atmospheric De-aliasing Models

    OpenAIRE

    YOU Wei

    2017-01-01

    Focusing on the problem that the spatial horizontal resolution of ECMWFop or ERA-Interim atmospheric data is not enough for the computation of atmospheric de-aliasing models in GRACE gravity recovery, a method of suitable fusion of local high spatial horizontal resolution atmospheric data and global atmospheric data is proposed. A set of improved atmospheric de-aliasing models is calculated by using the atmospheric data from the local area of Europe and ERA-Interim. The quality of the modifie...

  6. Horizontal stratified flow model for the 1-D module of WCOBRA/TRAC-TF2: modeling and validation

    International Nuclear Information System (INIS)

    Liao, J.; Frepoli, C.; Ohkawa, K.

    2011-01-01

    For a two-phase flow in a horizontal pipe, the individual phases may separate by gravity. This horizontal stratification significantly impacts the interfacial drag, interfacial heat transfer and wall drag of the two phase flow. For a PWR small break LOCA, the horizontal stratification in cold legs is a highly important phenomenon during loop seal clearance, boiloff and recovery periods. The low interfacial drag in the stratified flow directly controls the time period for the loop clearance and the level of residual water in the loop seal. Horizontal stratification in hot legs also impacts the natural circulation stage of a small break LOCA. In addition, the offtake phenomenon and cold leg condensation phenomenon are also affected by the occurrence of horizontal stratification in the cold legs. In the 1-D module of the WCOBRA/TRAC-TF2 computer code, a horizontal stratification criterion was developed by combining the Taitel-Dukler model and the Wallis-Dobson model, which approximates the viscous Kelvin-Helmholtz neutral stability boundary. The objective of this paper is to present the horizontal stratification model implemented in the code and its assessment against relevant data. The adequacy of the horizontal stratification transition criterion is confirmed by examining the code-predicted flow regime in a horizontal pipe with the measured data in the flow regime map. The void fractions (or liquid level) for the horizontal stratified flow in cold leg or hot leg are predicted with a reasonable accuracy. (author)

  7. Assimilating high horizontal resolution sea ice concentration data into the US Navy's ice forecast systems: Arctic Cap Nowcast/Forecast System (ACNFS) and the Global Ocean Forecast System (GOFS 3.1)

    Science.gov (United States)

    Posey, P. G.; Metzger, E. J.; Wallcraft, A. J.; Hebert, D. A.; Allard, R. A.; Smedstad, O. M.; Phelps, M. W.; Fetterer, F.; Stewart, J. S.; Meier, W. N.; Helfrich, S. R.

    2015-04-01

    This study presents the improvement in the US Navy's operational sea ice forecast systems gained by assimilating high horizontal resolution satellite-derived ice concentration products. Since the late 1980's, the ice forecast systems have assimilated near real-time sea ice concentration derived from the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSMI and then SSMIS). The resolution of the satellite-derived product was approximately the same as the previous operational ice forecast system (25 km). As the sea ice forecast model resolution increased over time, the need for higher horizontal resolution observational data grew. In 2013, a new Navy sea ice forecast system (Arctic Cap Nowcast/Forecast System - ACNFS) went into operations with a horizontal resolution of ~3.5 km at the North Pole. A method of blending ice concentration observations from the Advanced Microwave Scanning Radiometer (AMSR2) along with a sea ice mask produced by the National Ice Center (NIC) has been developed resulting in an ice concentration product with very high spatial resolution. In this study, ACNFS was initialized with this newly developed high resolution blended ice concentration product. The daily ice edge locations from model hindcast simulations were compared against independent observed ice edge locations. ACNFS initialized using the high resolution blended ice concentration data product decreased predicted ice edge location error compared to the operational system that only assimilated SSMIS data. A second evaluation assimilating the new blended sea ice concentration product into the pre-operational Navy Global Ocean Forecast System 3.1 also showed a substantial improvement in ice edge location over a system using the SSMIS sea ice concentration product alone. This paper describes the technique used to create the blended sea ice concentration product and the significant improvements to both of the Navy's sea ice forecasting systems.

  8. Diagnostic Evaluation of Ozone Production and Horizontal Transport in a Regional Photochemical Air Quality Modeling System

    Science.gov (United States)

    A diagnostic model evaluation effort has been performed to focus on photochemical ozone formation and the horizontal transport process since they strongly impact the temporal evolution and spatial distribution of ozone (O3) within the lower troposphere. Results from th...

  9. Applying horizontal diffusion on pressure surface to mesoscale models on terrain-following coordinates

    Science.gov (United States)

    Hann-Ming Henry Juang; Ching-Teng Lee; Yongxin Zhang; Yucheng Song; Ming-Chin Wu; Yi-Leng Chen; Kevin Kodama; Shyh-Chin Chen

    2005-01-01

    The National Centers for Environmental Prediction regional spectral model and mesoscale spectral model (NCEP RSM/MSM) use a spectral computation on perturbation. The perturbation is defined as a deviation between RSM/MSM forecast value and their outer model or analysis value on model sigma-coordinate surfaces. The horizontal diffusion used in the models applies...

  10. A model for diffuse and global irradiation on horizontal surface

    International Nuclear Information System (INIS)

    Jain, P.C.

    1984-01-01

    The intensity of the direct radiation and the diffuse radiation at any time on a horizontal surface are each expressed as fractions of the intensity of the extraterrestrial radiation. Using these and assuming a random distribution of the bright sunshine hours and not too wide variations in the values of the transmission coefficients, a number of relations for estimating the global and the diffuse irradiation are derived. Two of the relations derived are already known empirically. The formulation lends more confidence in the use of the already empirically known relations providing them a theoretical basis, and affords more flexibility to the estimation techniques by supplying new equations. The study identifies three independent basic parameters and the constants appearing in the various equations as simple functions of these three basic parameters. Experimental data for the diffuse irradiation, the global irradiation and the bright sunshine duration for Macerata (Italy), Salisbury and Bulawayo (Zimbabwe) is found to show good correlation for the linear equations, and the nature and the interrelationships of the constants are found to be as predicted by the theory

  11. A modified calculation model for groundwater flowing to horizontal ...

    Indian Academy of Sciences (India)

    All these valleys are located in Loess plateau of northern Shaanxi, China. The existing calculation model for single hori- zontal seepage well was built by Wang and Zhang. (2007) based on theory of coupled seepage-pipe flow and equivalent hydraulic conductivity (Chen. 1995; Chen and Lin 1998a, 1998b; Chen and.

  12. Can chemical transport models improve global horizontal irradiance forecasts?

    Czech Academy of Sciences Publication Activity Database

    Brabec, Marek; Konár, Ondřej; Resler, Jaroslav; Krč, Pavel; Pelikán, Emil; Eben, Kryštof

    2014-01-01

    Roč. 11, - (2014), EMS2014-404 [EMS Annual Meeting /14./ & European Conference on Applied Climatology (ECAC) /10./. 06.10.2014-10.10.2014, Prague] Institutional support: RVO:67985807 Keywords : renewable energy * mathematical modeling Subject RIV: DG - Athmosphere Sciences, Meteorology

  13. A cellular and molecular model of response kinetics and adaptation in primate cones and horizontal cells

    NARCIS (Netherlands)

    Hateren, Hans van

    2005-01-01

    A model for the sensitivity regulation in the primate outer retina is developed and validated using horizontal cell measurements from the literature. The main conclusion is that the phototransduction of the cones is the key factor regulating sensitivity. The model consists of a nonlinearity cascaded

  14. Modeling a horizontal wiggler in an electron storage ring

    International Nuclear Information System (INIS)

    Helm, R.H.

    1979-02-01

    The effects of a wiggler on the beam parameters depend on several integrals involving the machine functions and the field distribution in the wiggler. It is shown that these integrals are separable into sums of products of terms containing only the initial values of the machine functions, and terms containing integrals over the wiggler fields. The field-dependent integrals may be determined by numerical integrations based on measured field distribution. In typical wiggler designs, the energy and excitation dependencies of the integrals may be modeled mathematically by simple power series

  15. Evidence of horizontal and vertical transport of water in the Southern Hemisphere tropical tropopause layer (TTL from high-resolution balloon observations

    Directory of Open Access Journals (Sweden)

    S. M. Khaykin

    2016-09-01

    Full Text Available High-resolution in situ balloon measurements of water vapour, aerosol, methane and temperature in the upper tropical tropopause layer (TTL and lower stratosphere are used to evaluate the processes affecting the stratospheric water budget: horizontal transport (in-mixing and hydration by cross-tropopause overshooting updrafts. The obtained in situ evidence of these phenomena are analysed using satellite observations by Aura MLS (Microwave Limb Sounder and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation together with trajectory and transport modelling performed using CLaMS (Chemical Lagrangian Model of the Stratosphere and HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory model. Balloon soundings were conducted during March 2012 in Bauru, Brazil (22.3° S in the frame of the TRO-Pico campaign for studying the impact of convective overshooting on the stratospheric water budget. The balloon payloads included two stratospheric hygrometers: FLASH-B (Fluorescence Lyman-Alpha Stratospheric Hygrometer for Balloon and Pico-SDLA instrument as well as COBALD (Compact Optical Backscatter Aerosol Detector sondes, complemented by Vaisala RS92 radiosondes. Water vapour vertical profiles obtained independently by the two stratospheric hygrometers are in excellent agreement, ensuring credibility of the vertical structures observed. A signature of in-mixing is inferred from a series of vertical profiles, showing coincident enhancements in water vapour (of up to 0.5 ppmv and aerosol at the 425 K (18.5 km level. Trajectory analysis unambiguously links these features to intrusions from the Southern Hemisphere extratropical stratosphere, containing more water and aerosol, as demonstrated by MLS and CALIPSO global observations. The in-mixing is successfully reproduced by CLaMS simulations, showing a relatively moist filament extending to 20° S. A signature of local cross-tropopause transport of water is observed in

  16. Evidence of horizontal and vertical transport of water in the Southern Hemisphere tropical tropopause layer (TTL) from high-resolution balloon observations

    Science.gov (United States)

    Khaykin, Sergey M.; Pommereau, Jean-Pierre; Riviere, Emmanuel D.; Held, Gerhard; Ploeger, Felix; Ghysels, Melanie; Amarouche, Nadir; Vernier, Jean-Paul; Wienhold, Frank G.; Ionov, Dmitry

    2016-09-01

    High-resolution in situ balloon measurements of water vapour, aerosol, methane and temperature in the upper tropical tropopause layer (TTL) and lower stratosphere are used to evaluate the processes affecting the stratospheric water budget: horizontal transport (in-mixing) and hydration by cross-tropopause overshooting updrafts. The obtained in situ evidence of these phenomena are analysed using satellite observations by Aura MLS (Microwave Limb Sounder) and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) together with trajectory and transport modelling performed using CLaMS (Chemical Lagrangian Model of the Stratosphere) and HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model. Balloon soundings were conducted during March 2012 in Bauru, Brazil (22.3° S) in the frame of the TRO-Pico campaign for studying the impact of convective overshooting on the stratospheric water budget. The balloon payloads included two stratospheric hygrometers: FLASH-B (Fluorescence Lyman-Alpha Stratospheric Hygrometer for Balloon) and Pico-SDLA instrument as well as COBALD (Compact Optical Backscatter Aerosol Detector) sondes, complemented by Vaisala RS92 radiosondes. Water vapour vertical profiles obtained independently by the two stratospheric hygrometers are in excellent agreement, ensuring credibility of the vertical structures observed. A signature of in-mixing is inferred from a series of vertical profiles, showing coincident enhancements in water vapour (of up to 0.5 ppmv) and aerosol at the 425 K (18.5 km) level. Trajectory analysis unambiguously links these features to intrusions from the Southern Hemisphere extratropical stratosphere, containing more water and aerosol, as demonstrated by MLS and CALIPSO global observations. The in-mixing is successfully reproduced by CLaMS simulations, showing a relatively moist filament extending to 20° S. A signature of local cross-tropopause transport of water is observed in a particular

  17. Integrating autonomous Problem Resolution Models with Remedy

    OpenAIRE

    Marquina, M A; Padilla, J; Ramos, R

    2000-01-01

    This paper briefly defines the concept of Problem Resolution Model and shows possible approaches to the issues which may arise when integrating various PRMs to present a consistent view to the end user, despite of the peculiarities of each physical implementation. Integration refers to various autonomous PRMs having to interact as problems pass from one to another in the resolution flow. This process should be transparent to the user and internally there must be a way to track in which stage ...

  18. The effect of high-resolution orography on numerical modelling of atmospheric flow: a preliminary experiment

    International Nuclear Information System (INIS)

    Scarani, C.; Tampieri, F.; Tibaldi, S.

    1983-01-01

    The effect of increasing the resolution of the topography in models of numerical weather prediction is assessed. Different numerical experiments have been performed, referring to a case of cyclogenesis in the lee of the Alps. From the comparison, it appears that the lower atmospheric levels are better described by the model with higherresolution topography; comparable horizontal resolution runs with smoother topography appear to be less satisfactory in this respect. It turns out also that the vertical propagation of the signal due to the front-mountain interaction is faster in the high-resolution experiment

  19. A prototype 3-D simulation model for horizontal directional drilling associated with environmental remediation

    International Nuclear Information System (INIS)

    Allouche, E. N.; Ariaratnam, S. T.; Biggar, K. W.

    1997-01-01

    The use of horizontal directional drilling technology in environmental remediation projects was discussed. Three case histories are described to show the growth in the use of the technology in remediation applications. Further growth in the use of the technology is predicted as the cost of installation and risks borne by the contractor decline. Both of these impediments can be minimized by utilizing numerical tools such as modeling and simulation, which can contribute to reducing uncertainty and to increasing productivity. Details of one such application, named SEDDO (Simulation Environment of Horizontal Directional Drilling Operations), are provided. 10 refs., 3 figs

  20. Modeling a green inventory routing problem for perishable products with horizontal collaboration

    NARCIS (Netherlands)

    Soysal, M.; Bloemhof-Ruwaard, J.M.; Haijema, R.; Vorst, van der J.G.A.J.

    2017-01-01

    Increasing concerns on energy use, emissions and food waste require advanced models for food logistics management. Our interest in this study is to analyse the benefits of horizontal collaboration related to perishability, energy use (CO2 emissions) from transportation operations and logistics costs

  1. Regional modelling of tracer transport by tropical convection – Part 2: Sensitivity to model resolutions

    Directory of Open Access Journals (Sweden)

    J. Arteta

    2009-09-01

    Full Text Available The general objective of this series of two papers is to evaluate long duration limited-area simulations with idealised tracers as a possible tool to assess the tracer transport in chemistry-transport models (CTMs. In this second paper we analyse the results of three simulations using different horizontal and vertical resolutions. The goal is to study the impact of the model spatial resolution on convective transport of idealized tracer in the tropics. The reference simulation (REF uses a 60 km horizontal resolution and 300 m vertically in the upper troposphere/lower stratosphere (UTLS. A 20 km horizontal resolution simulation (HR is run as well as a simulation with 850 m vertical resolution in the UTLS (CVR. The simulations are run for one month during the SCOUT-O3 field campaign. Aircraft data, TRMM rainrate estimates and radiosoundings have been used to evaluate the simulations. They show that the HR configuration gives generally a better agreement with the measurements than the REF simulation. The CVR simulation gives generally the worst results. The vertical distribution of the tropospheric tracers for the simulations has a similar shape with a ~15 km altitude maximum for the 6h-lifetime tracer of 0.4 ppbv for REF, 1.2 for HR and 0.04 for CVR. These differences are related to the dynamics produced by the three simulations that leads to larger values of the upward velocities on average for HR and lower for CVR compared to REF. HR simulates more frequent and stronger convection leading to enhanced fluxes compared to REF and higher detrainment levels compared to CVR. HR provides also occasional overshoots over the cold point dynamical barrier. For the stratospheric tracers the differences between the three simulations are small. The diurnal cycle of the fluxes of all tracers in the Tropical Tropopause Layer exhibits a maximum linked to the maximum of convective activity.

  2. Rule-based Modelling and Tunable Resolution

    Directory of Open Access Journals (Sweden)

    Russ Harmer

    2009-11-01

    Full Text Available We investigate the use of an extension of rule-based modelling for cellular signalling to create a structured space of model variants. This enables the incremental development of rule sets that start from simple mechanisms and which, by a gradual increase in agent and rule resolution, evolve into more detailed descriptions.

  3. Mechanical and mathematical models of multi-stage horizontal fracturing strings and their application

    Directory of Open Access Journals (Sweden)

    Zhanghua Lian

    2015-03-01

    Full Text Available Multi-stage SRV fracturing in horizontal wells is a new technology developed at home and abroad in recent years to effectively develop shale gas or low-permeability reservoirs, but on the other hand makes the mechanical environment of fracturing strings more complicated at the same time. In view of this, based on the loading features of tubing strings during the multi-stage fracturing of a horizontal well, mechanical models were established for three working cases of multiple packer setting, open differential-pressure sliding sleeve, and open ball-injection sliding sleeve under a hold-down packer. Moreover, mathematical models were respectively built for the above three cases. According to the Lame formula and Von Mises stress calculation formula for the thick-walled cylinder in the theory of elastic mechanics, a mathematical model was also established to calculate the equivalent stress for tubing string safety evaluation when the fracturing string was under the combined action of inner pressure, external squeezing force and axial stress, and another mathematical model was built for the mechanical strength and safety evaluation of multi-stage fracturing strings. In addition, a practical software was developed for the mechanical safety evaluation of horizontal well multi-stage fracturing strings according to the mathematical model developed for the mechanical calculation of the multi-packer string in horizontal wells. The research results were applied and verified in a gas well of Tahe Oilfield in the Tarim Basin with excellent effects, providing a theoretical basis and a simple and reliable technical means for optimal design and safety evaluation of safe operational parameters of multi-stage fracturing strings in horizontal wells.

  4. Distributed Modeling with Parflow using High Resolution LIDAR Data

    Science.gov (United States)

    Barnes, M.; Welty, C.; Miller, A. J.

    2012-12-01

    Urban landscapes provide a challenging domain for the application of distributed surface-subsurface hydrologic models. Engineered water infrastructure and altered topography influence surface and subsurface flow paths, yet these effects are difficult to quantify. In this work, a parallel, distributed watershed model (ParFlow) is used to simulate urban watersheds using spatial data at the meter and sub-meter scale. An approach using GRASS GIS (Geographic Resources Analysis Support System) is presented that incorporates these data to construct inputs for the ParFlow simulation. LIDAR topography provides the basis for the fully coupled overland flow simulation. Methods to address real discontinuities in the urban land-surface for use with the grid-based kinematic wave approximation used in ParFlow are presented. The spatial distribution of impervious surface is delineated accurately from high-resolution land cover data; hydrogeological properties are specified from literature values. An application is presented for part of the Dead Run subwatershed of the Gwynns Falls in Baltimore County, MD. The domain is approximately 3 square kilometers, and includes a highly impacted urban stream, a major freeway, and heterogeneous urban development represented at a 10-m horizontal resolution and 1-m vertical resolution. This resolution captures urban features such as building footprints and highways at an appropriate scale. The Dead Run domain provides an effective test case for ParFlow application at the fine scale in an urban environment. Preliminary model runs employ a homogeneous subsurface domain with no-flow boundaries. Initial results reflect the highly articulated topography of the road network and the combined influence of surface runoff from impervious surfaces and subsurface flux toward the channel network. Subsequent model runs will include comparisons of the coupled surface-subsurface response of alternative versions of the Dead Run domain with and without impervious

  5. Modeling the Influence of Coseismic Horizontal Seafloor Displacement on Tsunami Generation and Propagation

    Science.gov (United States)

    Lotto, G. C.; Dunham, E. M.

    2014-12-01

    Conventional tsunami generation theory assumes that vertical uplift at the seafloor is entirely responsible for sea surface uplift after an earthquake. This vertical uplift, which includes direct vertical displacement as well as contributions from horizontal displacement of the sloped seabed, is low-pass filtered to account for nonhydrostatic ocean response at short wavelengths and used as an initial condition in tsunami models. However, Song et al. [2008] suggest that for geometries and horizontal displacements associated with realistic tsunamis, horizontal momentum transfer plays a key role in determining tsunami height. To gain insight into this problem, we use a provably stable and accurate finite difference method that can model the full seismic, ocean acoustic, and tsunami wavefield generated by megathrust earthquakes in two dimensions. This is done using summation-by-parts (SBP) finite difference operators and weak enforcement of boundary conditions via the simultaneous approximation term (SAT) method. Our numerical method rigorously couples the elastodynamic response of the solid Earth with that of a compressible ocean, in the presence of gravity. We model surface gravity waves using a linearized traction-free boundary condition on the perturbed free surface of an ocean initially in hydrostatic balance. We have applied our method to study the seismic, ocean acoustic, and tsunami waves generated by rupture on a thrust fault extending to the bottom of an ocean of constant depth. The results of our model disagree somewhat with the tsunami predicted by the standard approach; the amplitude of the landward traveling tsunami is smaller than predicted, while the amplitude of the seaward traveling tsunami is larger than predicted. We are presently studying if this difference is a directivity effect associated with up-dip rupture propagation or is related to horizontal momentum transfer to the ocean. Using our method, we have the potential to investigate tsunamis

  6. Prediction Model of Mechanical Extending Limits in Horizontal Drilling and Design Methods of Tubular Strings to Improve Limits

    Directory of Open Access Journals (Sweden)

    Wenjun Huang

    2017-01-01

    Full Text Available Mechanical extending limit in horizontal drilling means the maximum horizontal extending length of a horizontal well under certain ground and down-hole mechanical constraint conditions. Around this concept, the constrained optimization model of mechanical extending limits is built and simplified analytical results for pick-up and slack-off operations are deduced. The horizontal extending limits for kinds of tubular strings under different drilling parameters are calculated and drawn. To improve extending limits, an optimal design model of drill strings is built and applied to a case study. The results indicate that horizontal extending limits are underestimated a lot when the effects of friction force on critical helical buckling loads are neglected. Horizontal extending limits firstly increase and tend to stable values with vertical depths. Horizontal extending limits increase faster but finally become smaller with the increase of horizontal pushing forces for tubular strings of smaller modulus-weight ratio. Sliding slack-off is the main limit operation and high axial friction is the main constraint factor constraining horizontal extending limits. A sophisticated installation of multiple tubular strings can greatly inhibit helical buckling and increase horizontal extending limits. The optimal design model is called only once to obtain design results, which greatly increases the calculation efficiency.

  7. Generalized Lorenz models and their routes to chaos. II. Energy-conserving horizontal mode truncations

    International Nuclear Information System (INIS)

    Roy, D.; Musielak, Z.E.

    2007-01-01

    All attempts to generalize the three-dimensional Lorenz model by selecting higher-order Fourier modes can be divided into three categories, namely: vertical, horizontal and vertical-horizontal mode truncations. The previous study showed that the first method allowed only construction of a nine-dimensional system when the selected modes were energy-conserving. The results presented in this paper demonstrate that a five-dimensional model is the lowest-order generalized Lorenz model that can be constructed by the second method and that its route to chaos is the same as that observed in the original Lorenz model. It is shown that the onset of chaos in both systems is determined by a number of modes that describe the vertical temperature difference in a convection roll. In addition, a simple rule that allows selecting modes that conserve energy for each method is derived

  8. Interpolating and Estimating Horizontal Diffuse Solar Irradiation to Provide UK-Wide Coverage: Selection of the Best Performing Models

    Directory of Open Access Journals (Sweden)

    Diane Palmer

    2017-02-01

    Full Text Available Plane-of-array (PoA irradiation data is a requirement to simulate the energetic performance of photovoltaic devices (PVs. Normally, solar data is only available as global horizontal irradiation, for a limited number of locations, and typically in hourly time resolution. One approach to handling this restricted data is to enhance it initially by interpolation to the location of interest; next, it must be translated to PoA data by separately considering the diffuse and the beam components. There are many methods of interpolation. This research selects ordinary kriging as the best performing technique by studying mathematical properties, experimentation and leave-one-out-cross validation. Likewise, a number of different translation models has been developed, most of them parameterised for specific measurement setups and locations. The work presented identifies the optimum approach for the UK on a national scale. The global horizontal irradiation will be split into its constituent parts. Divers separation models were tried. The results of each separation algorithm were checked against measured data distributed across the UK. It became apparent that while there is little difference between procedures (14 Wh/m2 mean bias error (MBE, 12 Wh/m2 root mean square error (RMSE, the Ridley, Boland, Lauret equation (a universal split algorithm consistently performed well. The combined interpolation/separation RMSE is 86 Wh/m2.

  9. Moving towards Hyper-Resolution Hydrologic Modeling

    Science.gov (United States)

    Rouf, T.; Maggioni, V.; Houser, P.; Mei, Y.

    2017-12-01

    Developing a predictive capability for terrestrial hydrology across landscapes, with water, energy and nutrients as the drivers of these dynamic systems, faces the challenge of scaling meter-scale process understanding to practical modeling scales. Hyper-resolution land surface modeling can provide a framework for addressing science questions that we are not able to answer with coarse modeling scales. In this study, we develop a hyper-resolution forcing dataset from coarser resolution products using a physically based downscaling approach. These downscaling techniques rely on correlations with landscape variables, such as topography, roughness, and land cover. A proof-of-concept has been implemented over the Oklahoma domain, where high-resolution observations are available for validation purposes. Hourly NLDAS (North America Land Data Assimilation System) forcing data (i.e., near-surface air temperature, pressure, and humidity) have been downscaled to 500m resolution over the study area for 2015-present. Results show that correlation coefficients between the downscaled temperature dataset and ground observations are consistently higher than the ones between the NLDAS temperature data at their native resolution and ground observations. Not only correlation coefficients are higher, but also the deviation around the 1:1 line in the density scatterplots is smaller for the downscaled dataset than the original one with respect to the ground observations. Results are therefore encouraging as they demonstrate that the 500m temperature dataset has a good agreement with the ground information and can be adopted to force the land surface model for soil moisture estimation. The study has been expanded to wind speed and direction, incident longwave and shortwave radiation, pressure, and precipitation. Precipitation is well known to vary dramatically with elevation and orography. Therefore, we are pursuing a downscaling technique based on both topographical and vegetation

  10. Sensing Property Modeling for the Novel Horizontal-vertical Composite Underground Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Nanying Shentu

    2014-08-01

    Full Text Available Due to invisibility and complexity of the underground displacement monitoring, there exit few practical monitoring sensors capable of monitoring the underground horizontal and vertical displacements simultaneously. A novel electromagnetic underground displacement sensor able to monitor both the horizontal and the vertical displacements was proposed in our previous studies and abbreviated as the H-V type sensor. Through comprehensive application of Hall sensing mechanism analysis, 3D magnetic field distribution solution to the permanent magnet, and multidimensional numerical integration method, a model called the Equivalent Magnetic Charge-Numerical Integration Model (EMC-NI is presented in this paper and serves as the H-V type sensor’s Hall voltage measurement model. This model can quantitatively evaluate the complicated relationship among the sensor’s Hall voltage output, its measuring parameters (underground horizontal displacement, vertical displacement and tilt angle at different depth within the monitored soil rock mass and morphological parameters (geometry, shape and property parameters for the sensor units. Comprehensive studies and comparisons have conducted between the experimentally measured and EMC-NI modeled Hall voltage under counterpart conditions, through which not only the model’s modeling effectiveness and calculation accuracy are objectively evaluated, but also some valuable theoretical support is provided for the sensor’ sensing properties evaluation, design optimization, and subsequent study of displacement parameter inversion approach.

  11. Modeling the kinematic effect of horizontal strain rates on firn depth-density profiles

    Science.gov (United States)

    Horlings, A. N.; Stevens, C. M.; Holschuh, N.; Christianson, K. A.; Waddington, E. D.

    2017-12-01

    Firn compaction must be considered in interpretation of satellite repeat-altimetry measurements for ice-sheet mass balance estimates that are used to determine land-ice contribution to sea-level change. Firn compaction models remain the largest source of uncertainty in determining ice-sheet mass balance from repeat altimetry because the physical processes responsible for firn compaction are not fully understood. Most commonly used firn compaction models are 1-D, empirical or semi-empirical, and built on steady-state assumptions. These assumptions may be inappropriate in some regions, particularly areas of dynamic flow. In many of these regions, the horizontal strain rate due to dynamic ice flow can be similar in magnitude to the vertical strain rate from firn compaction. Therefore, horizontal stresses are important to consider in calculating firn depth-density profiles, yet are not represented in the current generation of firn compaction models. Here, we incorporate the kinematic effect of longitudinal strain on firn depth-density profiles in the dry snow zone. In every time step, the firn first densifies and consequently thins via a firn densification model; then, the firn stretches (thins) as stipulated by an imposed longitudinal strain rate without further density changes. Idealized tests show that the kinematic effect for longitudinal strain rates larger than 10-4 yr-1 can significantly decrease the depth-integrated porosity (> 0.5m) for climatic conditions representative of northeast Greenland. For conditions common on Thwaites Glacier, West Antarctica, results indicate that the kinematic effect on the firn column can shallow the bubble close-off depth by 20m and decrease the depth-integrated porosity by 7m. These results suggest that incorporating horizontal stresses into firn compaction models is essential to accurately model firn depth-density profiles in regions of ice sheets with high horizontal strain rates.

  12. Cirrus Horizontal Heterogeneity Effects on Cloud Optical Properties Retrieved from MODIS VNIR to TIR Channels as a Function of the Spatial Resolution

    Science.gov (United States)

    Fauchez, T.; Platnick, S. E.; Sourdeval, O.; Wang, C.; Meyer, K.; Cornet, C.; Szczap, F.

    2017-12-01

    Cirrus are an important part of the Earth radiation budget but an assessment of their role yet remains highly uncertain. Cirrus optical properties such as Cloud Optical Thickness (COT) and ice crystal effective particle size (Re) are often retrieved with a combination of Visible/Near InfraRed (VNIR) and ShortWave-InfraRed (SWIR) reflectance channels. Alternatively, Thermal InfraRed (TIR) techniques, such as the Split Window Technique (SWT), have demonstrated better sensitivity to thin cirrus. However, current satellite operational products for both retrieval methods assume that cloudy pixels are horizontally homogeneous (Plane Parallel and Homogeneous Approximation (PPHA)) and independent (Independent Pixel Approximation (IPA)). The impact of these approximations on cirrus retrievals needs to be understood and, as far as possible, corrected. Horizontal heterogeneity effects can be more easily estimated and corrected in the TIR range because they are mainly dominated by the PPA bias, which primarily depends on the COT subpixel heterogeneity. For solar reflectance channels, in addition to the PPHA bias, the IPA can lead to significant retrieval errors if there is large photon transport between cloudy columns in addition to brightening and shadowing effects that are more difficult to quantify.The effects of cirrus horizontal heterogeneity are here studied on COT and Re retrievals obtained using simulated MODIS reflectances at 0.86 and 2.11 μm and radiances at 8.5, 11.0 and 12.0 μm, for spatial resolutions ranging from 50 m to 10 km. For each spatial resolution, simulated TOA reflectances and radiances are combined for cloud optical property retrievals with a research-level optimal estimation retrieval method (OEM). The impact of horizontal heterogeneity on the retrieved products is assessed for different solar geometries and various combinations of the five channels.

  13. Impact of atmospheric model resolution on simulation of ENSO feedback processes: a coupled model study

    Science.gov (United States)

    Hua, Lijuan; Chen, Lin; Rong, Xinyao; Su, Jingzhi; Wang, Lu; Li, Tim; Yu, Yongqiang

    2018-03-01

    This study examines El Niño-Southern Oscillation (ENSO)-related air-sea feedback processes in a coupled general circulation model (CGCM) to gauge model errors and pin down their sources in ENSO simulation. Three horizontal resolutions of the atmospheric component (T42, T63 and T106) of the CGCM are used to investigate how the simulated ENSO behaviors are affected by the resolution. We find that air-sea feedback processes in the three experiments mainly differ in terms of both thermodynamic and dynamic feedbacks. We also find that these processes are simulated more reasonably in the highest resolution version than in the other two lower resolution versions. The difference in the thermodynamic feedback arises from the difference in the shortwave-radiation (SW) feedback. Due to the severely (mildly) excessive cold tongue in the lower (higher) resolution version, the SW feedback is severely (mildly) underestimated. The main difference in the dynamic feedback processes lies in the thermocline feedback and the zonal-advection feedback, both of which are caused by the difference in the anomalous thermocline response to anomalous zonal wind stress. The difference in representing the anomalous thermocline response is attributed to the difference in meridional structure of zonal wind stress anomaly in the three simulations, which is linked to meridional resolution.

  14. The horizontally homogeneous model equations of incompressible atmospheric flow in general orthogonal coordinates

    DEFF Research Database (Denmark)

    Jørgensen, Bo Hoffmann

    2003-01-01

    The goal of this brief report is to express the model equations for an incompressible flow which is horizontally homogeneous. It is intended as a computationally inexpensive starting point of a more complete solution for neutral atmospheric flow overcomplex terrain. This idea was set forth...... by Ayotte and Taylor (1995) and in the work of Beljaars et al. (1987). Unlike the previous models, the present work uses general orthogonal coordinates. Strong conservation form of the model equations is employedto allow a robust and consistent numerical procedure. An invariant tensor form of the model...

  15. Economic Integration and Quality Standards in a Duopoly Model with Horizontal and Vertical Product Differentiation

    DEFF Research Database (Denmark)

    Nielsen, Jørgen Ulff-Møller; Hansen, Jørgen Drud

    This paper examines the effects of trade barriers on quality levels in a duopoly model for two countries with one producer in each country. The products are both vertically and horizontally differentiated. In absence of quality regulation, the two producers determine prices and quality levels...... product. On the unregulated markets, integration increases welfare in both countries if they are almost of similar size. However, if the countries are very asymmetrical with respect to size, market integration may harm welfare in the large country. Welfare effects by introduction of minimum quality...... standards are also ambiguous depending on the parameters of the model. Keywords: Vertical product differentiation; horizontal product differentiation; market integration; duopoly; minimum quality standard. JEL: F12, F13, F14....

  16. A Comprehensive Comparison Study of Empirical Cutting Transport Models in Inclined and Horizontal Wells

    Directory of Open Access Journals (Sweden)

    Asep Mohamad Ishaq Shiddiq

    2017-07-01

    Full Text Available In deviated and horizontal drilling, hole-cleaning issues are a common and complex problem. This study explored the effect of various parameters in drilling operations and how they affect the flow rate required for effective cutting transport. Three models, developed following an empirical approach, were employed: Rudi-Shindu’s model, Hopkins’, and Tobenna’s model. Rudi-Shindu’s model needs iteration in the calculation. Firstly, the three models were compared using a sensitivity analysis of drilling parameters affecting cutting transport. The result shows that the models have similar trends but different values for minimum flow velocity. Analysis was conducted to examine the feasibility of using Rudi-Shindu’s, Hopkins’, and Tobenna’s models. The result showed that Hopkins’ model is limited by cutting size and revolution per minute (RPM. The minimum flow rate from Tobenna’s model is affected only by well inclination, drilling fluid weight and drilling fluid rheological property. Meanwhile, Rudi-Shindu’s model is limited by inclinations above 45°. The study showed that the investigated models are not suitable for horizontal wells because they do not include the effect of lateral section.

  17. Modelling, simulation and optimization of agricultural sprayer boom horizontal motion behaviour

    Directory of Open Access Journals (Sweden)

    Anna-Gret Borchert

    2015-08-01

    Full Text Available The study reported here presents a method offering realistic depiction of horizontal motion behaviour of agricultural sprayer booms and for reducing the extent of the simulation model involved. Additionally, various solutions of reducing boom vibrations are presented and compared with the help of simulation. Thereby is demonstrated the extent to which boom motion behaviour on booms with large working widths can be improved through passive vibration absorbers and an active vibration isolation.

  18. Numerical Modeling and Experimental Analysis of Scale Horizontal Axis Marine Hydrokinetic (MHK) Turbines

    Science.gov (United States)

    Javaherchi, Teymour; Stelzenmuller, Nick; Seydel, Joseph; Aliseda, Alberto

    2013-11-01

    We investigate, through a combination of scale model experiments and numerical simulations, the evolution of the flow field around the rotor and in the wake of Marine Hydrokinetic (MHK) turbines. Understanding the dynamics of this flow field is the key to optimizing the energy conversion of single devices and the arrangement of turbines in commercially viable arrays. This work presents a comparison between numerical and experimental results from two different case studies of scaled horizontal axis MHK turbines (45:1 scale). In the first case study, we investigate the effect of Reynolds number (Re = 40,000 to 100,000) and Tip Speed Ratio (TSR = 5 to 12) variation on the performance and wake structure of a single turbine. In the second case, we study the effect of the turbine downstream spacing (5d to 14d) on the performance and wake development in a coaxial configuration of two turbines. These results provide insights into the dynamics of Horizontal Axis Hydrokinetic Turbines, and by extension to Horizontal Axis Wind Turbines in close proximity to each other, and highlight the capabilities and limitations of the numerical models. Once validated at laboratory scale, the numerical model can be used to address other aspects of MHK turbines at full scale. Supported by DOE through the National Northwest Marine Renewable Energy Center.

  19. Soliton wave model for simulating the slug formation in vertical-to-horizontal partially blocked pipes

    International Nuclear Information System (INIS)

    Nihan Onder; Alberto Teyssedou; Danila Roubtsov

    2005-01-01

    velocity and the slug predominant frequency were obtained from the void fraction signals. The waves were filmed using a digital video camera and the frame images were used to extract their amplitudes. Even though, for co-current flows, the formation of slugs has been explained in terms of the Kelvin-Helmholtz instability criterion, we did not observe that the slugging phenomena were triggered by this type of instability. Thus, the objective of this paper is to provide a model that explain the formation of slugs in a CCF. The model is based on the Boussinesq nonlinear system of equations that are discretized by using leap-frog scheme and solved numerically. The results have been used to obtain the slug frequency and propagation velocity. We have calculated the slug frequency from the lag time between the instant a train of solitons are formed in the horizontal leg and the instant that two trains of solitons collide with each other to form a slug. The slug propagation velocity has been estimated by using a control volume approach, the average horizontal velocity given by the model and the velocity of gravitational waves. The predictions of the model were compared with the slug data; in general, a good agreement between the predictions and the data was found. (authors)

  20. High resolution extremity CT for biomechanics modeling

    International Nuclear Information System (INIS)

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-01-01

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling

  1. High resolution extremity CT for biomechanics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-09-23

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling.

  2. Near-wellbore modeling of a horizontal well with Computational Fluid Dynamics

    DEFF Research Database (Denmark)

    Szanyi, Márton L.; Hemmingsen, Casper Schytte; Yan, Wei

    2018-01-01

    horizontal well producing from the Siri field, offshore Denmark. The performance of the well is investigated with an emphasis on the inflow profile and the productivity index for different formation damage scenarios. A considerable redistribution of the inflow profile were found when the filtrate invasion...... dimensional numerical models, to predict the inflow to the well. The present study considers the applicability of CFD for near-wellbore modeling through benchmark cases with available analytical solutions. Moreover, single phase steady-state numerical investigations are performed on a specific perforated...

  3. A numerical model for the thermal history of rocks based on confined horizontal fission tracks

    DEFF Research Database (Denmark)

    Jensen, Peter Klint; Hansen, Kirsten; Kunzendorf, Helmar

    1992-01-01

    A numerical model for determination of the thermal history of rocks is presented. It is shown that the thermal history may be uniquely determined as a piece-by-piece linear function on the basis of etched confined, horizontal fission track length distributions, their surface densities...... measured in transmitted light are biased favouring short tracks compared with measurements in reflected light. Testing of the model is performed on apatites from a tuffaceous sandstone from Bornholm (Denmark) yielding an estimate of the thermal history for the period of about 280 Ma back in time....

  4. Modeling of global horizontal irradiance in the United Arab Emirates with artificial neural networks

    International Nuclear Information System (INIS)

    Hejase, Hassan A.N.; Al-Shamisi, Maitha H.; Assi, Ali H.

    2014-01-01

    This paper employs ANN (Artificial Neural Network) models to estimate GHI (global horizontal irradiance) for three major cities in the UAE (United Arab Emirates), namely Abu Dhabi, Dubai and Al-Ain. City data are then used to develop a comprehensive global GHI model for other nearby locations in the UAE. The ANN models use MLP (Multi-Layer Perceptron) and RBF (Radial Basis Function) techniques with comprehensive training algorithms, architectures, and different combinations of inputs. The UAE models are tested and validated against individual city models and data available from the UAE Solar Atlas with good agreement as attested by the computed statistical error parameters. The optimal ANN model is MLP-based and requires four mean daily weather parameters; namely, maximum temperature, wind speed, sunshine hours, and relative humidity. The computed statistical error parameters for the optimal MLP-ANN model in relation to the measured three-cities mean data (referred to as UAE data) are MBE (mean bias error) = −0.0003 kWh/m 2 , RMSE = 0.179 kWh/m 2 , R 2  = 99%, NSE (Nash-Sutcliffe model Efficiency coefficient) = 99%, and t-statistic = 0.005 at 5% significance level. Results prove the suitability of the ANN models for estimating the monthly mean daily GHI in different locations of the UAE. - Highlights: • ANN prediction models for the GHI (global horizontal irradiance) in the UAE. • Models used to estimate the potential of global solar radiation for UAE cities. • Data from the UAE Solar Atlas are used to validate developed ANN models. • ANN models are more efficient than regression models in predicting GHI

  5. Decadal prediction skill using a high-resolution climate model

    Science.gov (United States)

    Monerie, Paul-Arthur; Coquart, Laure; Maisonnave, Éric; Moine, Marie-Pierre; Terray, Laurent; Valcke, Sophie

    2017-11-01

    The ability of a high-resolution coupled atmosphere-ocean general circulation model (with a horizontal resolution of a quarter of a degree in the ocean and of about 0.5° in the atmosphere) to predict the annual means of temperature, precipitation, sea-ice volume and extent is assessed based on initialized hindcasts over the 1993-2009 period. Significant skill in predicting sea surface temperatures is obtained, especially over the North Atlantic, the tropical Atlantic and the Indian Ocean. The Sea Ice Extent and volume are also reasonably predicted in winter (March) and summer (September). The model skill is mainly due to the external forcing associated with well-mixed greenhouse gases. A decrease in the global warming rate associated with a negative phase of the Pacific Decadal Oscillation is simulated by the model over a suite of 10-year periods when initialized from starting dates between 1999 and 2003. The model ability to predict regional change is investigated by focusing on the mid-90's Atlantic Ocean subpolar gyre warming. The model simulates the North Atlantic warming associated with a meridional heat transport increase, a strengthening of the North Atlantic current and a deepening of the mixed layer over the Labrador Sea. The atmosphere plays a role in the warming through a modulation of the North Atlantic Oscillation: a negative sea level pressure anomaly, located south of the subpolar gyre is associated with a wind speed decrease over the subpolar gyre. This leads to a reduced oceanic heat-loss and favors a northward displacement of anomalously warm and salty subtropical water that both concur to the subpolar gyre warming. We finally conclude that the subpolar gyre warming is mainly triggered by ocean dynamics with a possible contribution of atmospheric circulation favoring its persistence.

  6. The influence of model resolution on ozone in industrial volatile organic compound plumes.

    Science.gov (United States)

    Henderson, Barron H; Jeffries, Harvey E; Kim, Byeong-Uk; Vizuete, William G

    2010-09-01

    Regions with concentrated petrochemical industrial activity (e.g., Houston or Baton Rouge) frequently experience large, localized releases of volatile organic compounds (VOCs). Aircraft measurements suggest these released VOCs create plumes with ozone (O3) production rates 2-5 times higher than typical urban conditions. Modeling studies found that simulating high O3 productions requires superfine (1-km) horizontal grid cell size. Compared with fine modeling (4-kmin), the superfine resolution increases the peak O3 concentration by as much as 46%. To understand this drastic O3 change, this study quantifies model processes for O3 and "odd oxygen" (Ox) in both resolutions. For the entire plume, the superfine resolution increases the maximum O3 concentration 3% but only decreases the maximum Ox concentration 0.2%. The two grid sizes produce approximately equal Ox mass but by different reaction pathways. Derived sensitivity to oxides of nitrogen (NOx) and VOC emissions suggests resolution-specific sensitivity to NOx and VOC emissions. Different sensitivity to emissions will result in different O3 responses to subsequently encountered emissions (within the city or downwind). Sensitivity of O3 to emission changes also results in different simulated O3 responses to the same control strategies. Sensitivity of O3 to NOx and VOC emission changes is attributed to finer resolved Eulerian grid and finer resolved NOx emissions. Urban NOx concentration gradients are often caused by roadway mobile sources that would not typically be addressed with Plume-in-Grid models. This study shows that grid cell size (an artifact of modeling) influences simulated control strategies and could bias regulatory decisions. Understanding the dynamics of VOC plume dependence on grid size is the first step toward providing more detailed guidance for resolution. These results underscore VOC and NOx resolution interdependencies best addressed by finer resolution. On the basis of these results, the

  7. A method to predict geomechanical properties and model well stability in horizontal boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Gentzis, Thomas [Petron Resources, L.P., 3000 Internet Boulevard, Suite 400, Frisco, TX 75034 (United States); Deisman, Nathan; Chalaturnyk, Richard J. [Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB (Canada)

    2009-04-01

    A methodology is proposed to quickly assess the stability risk for horizontal wells drilled in coal seams. The first task involves the estimation of strength and deformation parameters of the coal by indirect methods, such as the use of core description to assign a Geological Strength Index (Gi). The second task involves the use of a finite element analysis called FLAC to investigate factors such as the depth of fluid penetration while drilling the horizontal well and the stability of the wellbore during simulated production. These two factors are important because coal fines generated by the drill bit action are carried by the drilling fluid into the cleat system of the coal, thereby plugging the permeability pathways, and causing formation damage. On the other hand, a wellbore that may become unstable during pressure drawdown would require a perforated or slotted production liner. In this study, the conditions of drilling and production necessary for a stable horizontal well drilled into a Mannville coal seam at 750-800 m in the central Alberta Plains, were studied. Modeling showed that the depth of fluid penetration would be at least 2.2 m if there is no filter cake formation while drilling underbalanced. Drilling fluid penetration would be minimal if a filter cake is formed under overbalanced conditions. Furthermore, FLAC analysis showed that drilling a smaller diameter hole (5 cm) would be preferable because this size results in a stable wellbore during production compared to the standard 15-cm diameter hole. (author)

  8. A high resolution WRF model for wind energy forecasting

    Science.gov (United States)

    Vincent, Claire Louise; Liu, Yubao

    2010-05-01

    The increasing penetration of wind energy into national electricity markets has increased the demand for accurate surface layer wind forecasts. There has recently been a focus on forecasting the wind at wind farm sites using both statistical models and numerical weather prediction (NWP) models. Recent advances in computing capacity and non-hydrostatic NWP models means that it is possible to nest mesoscale models down to Large Eddy Simulation (LES) scales over the spatial area of a typical wind farm. For example, the WRF model (Skamarock 2008) has been run at a resolution of 123 m over a wind farm site in complex terrain in Colorado (Liu et al. 2009). Although these modelling attempts indicate a great hope for applying such models for detailed wind forecasts over wind farms, one of the obvious challenges of running the model at this resolution is that while some boundary layer structures are expected to be modelled explicitly, boundary layer eddies into the inertial sub-range can only be partly captured. Therefore, the amount and nature of sub-grid-scale mixing that is required is uncertain. Analysis of Liu et al. (2009) modelling results in comparison to wind farm observations indicates that unrealistic wind speed fluctuations with a period of around 1 hour occasionally occurred during the two day modelling period. The problem was addressed by re-running the same modelling system with a) a modified diffusion constant and b) two-way nesting between the high resolution model and its parent domain. The model, which was run with horizontal grid spacing of 370 m, had dimensions of 505 grid points in the east-west direction and 490 points in the north-south direction. It received boundary conditions from a mesoscale model of resolution 1111 m. Both models had 37 levels in the vertical. The mesoscale model was run with a non-local-mixing planetary boundary layer scheme, while the 370 m model was run with no planetary boundary layer scheme. It was found that increasing the

  9. Fine reservoir structure modeling based upon 3D visualized stratigraphic correlation between horizontal wells: methodology and its application

    Science.gov (United States)

    Chenghua, Ou; Chaochun, Li; Siyuan, Huang; Sheng, James J.; Yuan, Xu

    2017-12-01

    As the platform-based horizontal well production mode has been widely applied in petroleum industry, building a reliable fine reservoir structure model by using horizontal well stratigraphic correlation has become very important. Horizontal wells usually extend between the upper and bottom boundaries of the target formation, with limited penetration points. Using these limited penetration points to conduct well deviation correction means the formation depth information obtained is not accurate, which makes it hard to build a fine structure model. In order to solve this problem, a method of fine reservoir structure modeling, based on 3D visualized stratigraphic correlation among horizontal wells, is proposed. This method can increase the accuracy when estimating the depth of the penetration points, and can also effectively predict the top and bottom interfaces in the horizontal penetrating section. Moreover, this method will greatly increase not only the number of points of depth data available, but also the accuracy of these data, which achieves the goal of building a reliable fine reservoir structure model by using the stratigraphic correlation among horizontal wells. Using this method, four 3D fine structure layer models have been successfully built of a specimen shale gas field with platform-based horizontal well production mode. The shale gas field is located to the east of Sichuan Basin, China; the successful application of the method has proven its feasibility and reliability.

  10. Modelling and control of growing slugs in horizontal multiphase pipe flows

    Directory of Open Access Journals (Sweden)

    Steinar M. Elgsæter

    2006-07-01

    Full Text Available In this paper, the use of active control to restrict the length of growing slugs in horizontal pipelines is investigated. Specifically, the paper attempts to determine if such control can be attained with realistic measurements and actuators. Simulations in OLGA2000 show that a feedback controller can use measurements or estimates of slug length to control the growth of a slug in a horizontal pipeline by partially closing inlet or outlet chokes. A control-volume approach is used to develop a low-order model of inlet choke-slug growth dynamics based on mass- and impulse balances. The resulting model is a system of nonlinear differential-algebraic equations, which is suitable for observer-design. The tuned model is found to be in good agreement with experiments and OLGA2000-simulations. Linearizations of the model are found to be observable around realistic trajectories when rates and pressures at the inlet and outlet are measured. An extended Luenberger-observer is shown to give good estimates of slug length and -position in simulations even under model uncertainty.

  11. A New Model to Predict Productivity of Multiple-Fractured Horizontal Well in Naturally Fractured Reservoirs

    Directory of Open Access Journals (Sweden)

    Junchao Wang

    2015-01-01

    Full Text Available In order to predict productivity of multiple-fractured horizontal well in fractured reservoir, flow models of reservoir and hydraulic fractures based on the volumetric source idealization are developed. The models are solved by utilizing Laplace transformation and orthogonal transformation, and flow rate of the well is calculated by coupling the two models. Compared to traditional point source functions, volumetric source function has many advantages in properties of function and programming calculation. The productivity predicting model is verified via an analytical ternary-porosity model. Moreover, a practical example of fractured horizontal well is studied to analyze the productivity and its influent factors. The result shows that flow rate of each fracture is different and inner fracture contributes least to productivity. Meanwhile, there are optimizing ranges for number, length, and conductivity of hydraulic fractures. In low-permeability reservoir, increasing surface area in contact with reservoir by increasing number and length of hydraulic fractures is the most effective method to improve the productivity.

  12. What model resolution is required in climatological downscaling over complex terrain?

    Science.gov (United States)

    El-Samra, Renalda; Bou-Zeid, Elie; El-Fadel, Mutasem

    2018-05-01

    This study presents results from the Weather Research and Forecasting (WRF) model applied for climatological downscaling simulations over highly complex terrain along the Eastern Mediterranean. We sequentially downscale general circulation model results, for a mild and wet year (2003) and a hot and dry year (2010), to three local horizontal resolutions of 9, 3 and 1 km. Simulated near-surface hydrometeorological variables are compared at different time scales against data from an observational network over the study area comprising rain gauges, anemometers, and thermometers. The overall performance of WRF at 1 and 3 km horizontal resolution was satisfactory, with significant improvement over the 9 km downscaling simulation. The total yearly precipitation from WRF's 1 km and 3 km domains exhibited Wind speeds, on the other hand, are generally overestimated for all model resolutions, in comparison with observational data, particularly on the coast (up to 50%) compared to inland stations (up to 40%). The findings therefore indicate that a 3 km resolution is sufficient for the downscaling, especially that it would allow more years and scenarios to be investigated compared to the higher 1 km resolution at the same computational effort. In addition, the results provide a quantitative measure of the potential errors for various hydrometeorological variables.

  13. Integrating autonomous Problem Resolution Models with Remedy

    CERN Document Server

    Marquina, M A; Ramos, R

    2000-01-01

    This paper briefly defines the concept of Problem Resolution Model and shows possible approaches to the issues which may arise when integrating various PRMs to present a consistent view to the end user, despite of the peculiarities of each physical implementation. Integration refers to various autonomous PRMs having to interact as problems pass from one to another in the resolution flow. This process should be transparent to the user and internally there must be a way to track in which stage of the resolution process any problem is. This means addressing two different issues. On one side PRMs which are to be integrated need to comply with certain interface standards. These standards must ensure that problems exchanged between them can always be traced. On the other side problems owned by different PRMs should be presented to the end user under a homogeneous view. This means having an uniform criteria for automatic notification messages, a single reference point (www) where users can query the status of proble...

  14. Using a stand-level model to predict light absorption in stands with vertically and horizontally heterogeneous canopies

    Directory of Open Access Journals (Sweden)

    David I Forrester

    2014-09-01

    Full Text Available Background Forest ecosystem functioning is strongly influenced by the absorption of photosynthetically active radiation (APAR, and therefore, accurate predictions of APAR are critical for many process-based forest growth models. The Lambert-Beer law can be applied to estimate APAR for simple homogeneous canopies composed of one layer, one species, and no canopy gaps. However, the vertical and horizontal structure of forest canopies is rarely homogeneous. Detailed tree-level models can account for this heterogeneity but these often have high input and computational demands and work on finer temporal and spatial resolutions than required by stand-level growth models. The aim of this study was to test a stand-level light absorption model that can estimate APAR by individual species in mixed-species and multi-layered stands with any degree of canopy openness including open-grown trees to closed canopies. Methods The stand-level model was compared with a detailed tree-level model that has already been tested in mixed-species stands using empirical data. Both models were parameterised for five different forests, including a wide range of species compositions, species proportions, stand densities, crown architectures and canopy structures. Results The stand-level model performed well in all stands except in the stand where extinction coefficients were unusually variable and it appears unlikely that APAR could be predicted in such stands using (tree- or stand-level models that do not allow individuals of a given species to have different extinction coefficients, leaf-area density or analogous parameters. Conclusion This model is parameterised with species-specific information about extinction coefficients and mean crown length, diameter, height and leaf area. It could be used to examine light dynamics in complex canopies and in stand-level growth models.

  15. A Simple Physics-Based Model Predicts Oil Production from Thousands of Horizontal Wells in Shales

    KAUST Repository

    Patzek, Tadeusz

    2017-10-18

    Over the last six years, crude oil production from shales and ultra-deep GOM in the United States has accounted for most of the net increase of global oil production. Therefore, it is important to have a good predictive model of oil production and ultimate recovery in shale wells. Here we introduce a simple model of producing oil and solution gas from the horizontal hydrofractured wells. This model is consistent with the basic physics and geometry of the extraction process. We then apply our model thousands of wells in the Eagle Ford shale. Given well geometry, we obtain a one-dimensional nonlinear pressure diffusion equation that governs flow of mostly oil and solution gas. In principle, solutions of this equation depend on many parameters, but in practice and within a given oil shale, all but three can be fixed at typical values, leading to a nonlinear diffusion problem we linearize and solve exactly with a scaling

  16. High Resolution Hurricane Storm Surge and Inundation Modeling (Invited)

    Science.gov (United States)

    Luettich, R.; Westerink, J. J.

    2010-12-01

    Coastal counties are home to nearly 60% of the U.S. population and industry that accounts for over 16 million jobs and 10% of the U.S. annual gross domestic product. However, these areas are susceptible to some of the most destructive forces in nature, including tsunamis, floods, and severe storm-related hazards. Since 1900, tropical cyclones making landfall on the US Gulf of Mexico Coast have caused more than 9,000 deaths; nearly 2,000 deaths have occurred during the past half century. Tropical cyclone-related adjusted, annualized losses in the US have risen from 1.3 billion from 1949-1989, to 10.1 billion from 1990-1995, and $35.8 billion per year for the period 2001-2005. The risk associated with living and doing business in the coastal areas that are most susceptible to tropical cyclones is exacerbated by rising sea level and changes in the characteristics of severe storms associated with global climate change. In the five years since hurricane Katrina devastated the northern Gulf of Mexico Coast, considerable progress has been made in the development and utilization of high resolution coupled storm surge and wave models. Recent progress will be presented with the ADCIRC + SWAN storm surge and wave models. These tightly coupled models use a common unstructured grid in the horizontal that is capable of covering large areas while also providing high resolution (i.e., base resolution down to 20m plus smaller subgrid scale features such as sea walls and levees) in areas that are subject to surge and inundation. Hydrodynamic friction and overland winds are adjusted to account for local land cover. The models scale extremely well on modern high performance computers allowing rapid turnaround on large numbers of compute cores. The models have been adopted for FEMA National Flood Insurance Program studies, hurricane protection system design and risk analysis, and quasi-operational forecast systems for several regions of the country. They are also being evaluated as

  17. High Resolution Model Intercomparison Project (HighResMIP v1.0 for CMIP6

    Directory of Open Access Journals (Sweden)

    R. J. Haarsma

    2016-11-01

    Full Text Available Robust projections and predictions of climate variability and change, particularly at regional scales, rely on the driving processes being represented with fidelity in model simulations. The role of enhanced horizontal resolution in improved process representation in all components of the climate system is of growing interest, particularly as some recent simulations suggest both the possibility of significant changes in large-scale aspects of circulation as well as improvements in small-scale processes and extremes. However, such high-resolution global simulations at climate timescales, with resolutions of at least 50 km in the atmosphere and 0.25° in the ocean, have been performed at relatively few research centres and generally without overall coordination, primarily due to their computational cost. Assessing the robustness of the response of simulated climate to model resolution requires a large multi-model ensemble using a coordinated set of experiments. The Coupled Model Intercomparison Project 6 (CMIP6 is the ideal framework within which to conduct such a study, due to the strong link to models being developed for the CMIP DECK experiments and other model intercomparison projects (MIPs. Increases in high-performance computing (HPC resources, as well as the revised experimental design for CMIP6, now enable a detailed investigation of the impact of increased resolution up to synoptic weather scales on the simulated mean climate and its variability. The High Resolution Model Intercomparison Project (HighResMIP presented in this paper applies, for the first time, a multi-model approach to the systematic investigation of the impact of horizontal resolution. A coordinated set of experiments has been designed to assess both a standard and an enhanced horizontal-resolution simulation in the atmosphere and ocean. The set of HighResMIP experiments is divided into three tiers consisting of atmosphere-only and coupled runs and spanning the period

  18. A Physically Based Horizontal Subgrid-scale Turbulent Mixing Parameterization for the Convective Boundary Layer in Mesoscale Models

    Science.gov (United States)

    Zhou, Bowen; Xue, Ming; Zhu, Kefeng

    2017-04-01

    Compared to the representation of vertical turbulent mixing through various PBL schemes, the treatment of horizontal turbulence mixing in the boundary layer within mesoscale models, with O(10) km horizontal grid spacing, has received much less attention. In mesoscale models, subgrid-scale horizontal fluxes most often adopt the gradient-diffusion assumption. The horizontal mixing coefficients are usually set to a constant, or through the 2D Smagorinsky formulation, or in some cases based on the 1.5-order turbulence kinetic energy (TKE) closure. In this work, horizontal turbulent mixing parameterizations using physically based characteristic velocity and length scales are proposed for the convective boundary layer based on analysis of a well-resolved, wide-domain large-eddy simulation (LES). The proposed schemes involve different levels of sophistication. The first two schemes can be used together with first-order PBL schemes, while the third uses TKE to define its characteristic velocity scale and can be used together with TKE-based higher-order PBL schemes. The current horizontal mixing formulations are also assessed a priori through the filtered LES results to illustrate their limitations. The proposed parameterizations are tested a posteriori in idealized simulations of turbulent dispersion of a passive scalar. Comparisons show improved horizontal dispersion by the proposed schemes, and further demonstrate the weakness of the current schemes.

  19. A numerical model for the thermal history of rocks based on confined horizontal fission tracks

    International Nuclear Information System (INIS)

    Jensen, P.K.; Kunzendorf, Helmar; Hansen, Kirsten

    1992-01-01

    A numerical model for determination of the thermal history of rocks is presented. It is shown that the thermal history may be uniquely determined as a piece-by-piece linear function on the basis of etched confined, horizontal fission track length distributions, their surface densities, and the uranium content. The initial track length distribution is taken into account. A relation between the measured track length distribution and age is given which includes correction for partial annealing. The annealing model used is the fanning Arrhenius plot. It is shown that track length distributions measured in transmitted light are biased favouring short tracks compared with measurements in reflected light. Testing of the model is performed on apatites from a tuffaceous sandstone from Bornholm (Denmark) yielding an estimate of the thermal history for the period of about 280 Ma back in time. (author)

  20. Advanced Reservoir Characterization and Development through High-Resolution 3C3D Seismic and Horizontal Drilling: Eva South Marrow Sand Unit, Texas County, Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler,David M.; Miller, William A.; Wilson, Travis C.

    2002-03-11

    The Eva South Morrow Sand Unit is located in western Texas County, Oklahoma. The field produces from an upper Morrow sandstone, termed the Eva sandstone, deposited in a transgressive valley-fill sequence. The field is defined as a combination structural stratigraphic trap; the reservoir lies in a convex up -dip bend in the valley and is truncated on the west side by the Teepee Creek fault. Although the field has been a successful waterflood since 1993, reservoir heterogeneity and compartmentalization has impeded overall sweep efficiency. A 4.25 square mile high-resolution, three component three-dimensional (3C3D) seismic survey was acquired in order to improve reservoir characterization and pinpoint the optimal location of a new horizontal producing well, the ESU 13-H.

  1. Multi-resolution voxel phantom modeling: a high-resolution eye model for computational dosimetry.

    Science.gov (United States)

    Caracappa, Peter F; Rhodes, Ashley; Fiedler, Derek

    2014-09-21

    Voxel models of the human body are commonly used for simulating radiation dose with a Monte Carlo radiation transport code. Due to memory limitations, the voxel resolution of these computational phantoms is typically too large to accurately represent the dimensions of small features such as the eye. Recently reduced recommended dose limits to the lens of the eye, which is a radiosensitive tissue with a significant concern for cataract formation, has lent increased importance to understanding the dose to this tissue. A high-resolution eye model is constructed using physiological data for the dimensions of radiosensitive tissues, and combined with an existing set of whole-body models to form a multi-resolution voxel phantom, which is used with the MCNPX code to calculate radiation dose from various exposure types. This phantom provides an accurate representation of the radiation transport through the structures of the eye. Two alternate methods of including a high-resolution eye model within an existing whole-body model are developed. The accuracy and performance of each method is compared against existing computational phantoms.

  2. The M-2 ocean tide loading wave in Alaska: vertical and horizontal displacements, modelled and observed

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Scherneck, H.G.

    2003-01-01

    Crustal deformations caused by surface load due to ocean tides are strongly dependent on the surface load closest to the observing site. In order to correctly model this ocean loading effect near irregular coastal areas, a high-resolution coastline is required. A test is carried out using two GPS...

  3. Horizontal ground coupled heat pump: Thermal-economic modeling and optimization

    International Nuclear Information System (INIS)

    Sanaye, Sepehr; Niroomand, Behzad

    2010-01-01

    The modeling and optimizing processes of a Ground Coupled Heat Pump (GCHP) with closed Horizontal Ground Heat eXchanger (HGHX) are presented in this paper. After thermal modeling of GCHP including HGHX, the optimum design parameters of the system were estimated by minimizing a defined objective function (total of investment and operation costs) subject to a list of constraints. This procedure was performed applying Genetic Algorithm technique. For given heating/cooling loads and various climatic conditions, the optimum values of saturated temperature/pressure of condenser and evaporator as well as inlet and outlet temperatures of the water source in cooling and heating modes were predicted. Then, for our case study, the design parameters as well as the configuration of HGHX were obtained. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, and soil type were discussed.

  4. Horizontal, anomalous U(1) symmetry for the more minimal supersymmetric standard model

    International Nuclear Information System (INIS)

    Nelson, A.E.; Wright, D.

    1997-01-01

    We construct explicit examples with a horizontal, open-quotes anomalousclose quotes U(1) gauge group, which, in a supersymmetric extension of the standard model, reproduce qualitative features of the fermion spectrum and CKM matrix, and suppress FCNC and proton decay rates without the imposition of global symmetries. We review the motivation for such open-quotes moreclose quotes minimal supersymmetric standard models and their predictions for the sparticle spectrum. There is a mass hierarchy in the scalar sector which is the inverse of the fermion mass hierarchy. We show in detail why ΔS=2 FCNCs are greatly suppressed when compared with naive estimates for nondegenerate squarks. copyright 1997 The American Physical Society

  5. Simulation of horizontal pipe two-phase slug flows using the two-fluid model

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Malca, Arturo J. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica. Nucleo de Simulacao Termohidraulica de Dutos (SIMDUT); Nieckele, Angela O. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica

    2005-07-01

    Slug flow occurs in many engineering applications, mainly in the transport of hydrocarbon fluids in pipelines. The intermittency of slug flow causes severe unsteady loading on the pipelines carrying the fluids, which gives rise to design problems. Therefore, it is important to be able to predict the onset and development of slug flow as well as slug characteristics. The present work consists in the simulation of two-phase flow in slug pattern through horizontal pipes using the two-fluid model in its transient and one-dimensional form. The advantage of this model is that the flow field is allowed to develop naturally from a given initial conditions as part of the transient calculation; the slug evolves automatically as a product of the computed flow development. Simulations are then carried out for a large number of flow conditions that lead a slug flow. (author)

  6. A Variable Resolution Stretched Grid General Circulation Model: Regional Climate Simulation

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.; Takacs, Lawrence L.; Govindaraju, Ravi C.; Suarez, Max J.

    2000-01-01

    The development of and results obtained with a variable resolution stretched-grid GCM for the regional climate simulation mode, are presented. A global variable resolution stretched- grid used in the study has enhanced horizontal resolution over the U.S. as the area of interest The stretched-grid approach is an ideal tool for representing regional to global scale interaction& It is an alternative to the widely used nested grid approach introduced over a decade ago as a pioneering step in regional climate modeling. The major results of the study are presented for the successful stretched-grid GCM simulation of the anomalous climate event of the 1988 U.S. summer drought- The straightforward (with no updates) two month simulation is performed with 60 km regional resolution- The major drought fields, patterns and characteristics such as the time averaged 500 hPa heights precipitation and the low level jet over the drought area. appear to be close to the verifying analyses for the stretched-grid simulation- In other words, the stretched-grid GCM provides an efficient down-scaling over the area of interest with enhanced horizontal resolution. It is also shown that the GCM skill is sustained throughout the simulation extended to one year. The developed and tested in a simulation mode stretched-grid GCM is a viable tool for regional and subregional climate studies and applications.

  7. Productivity model for gas reservoirs with open-hole multi-fracturing horizontal wells and optimization of hydraulic fracture parameters

    Directory of Open Access Journals (Sweden)

    Jianqiang Xue

    2017-12-01

    Full Text Available Multi-fractured horizontal wells are commonly employed to improve the productivity of low and ultra-low permeability gas reservoirs. However, conventional productivity models for open-hole multi-fractured horizontal wells do not consider the interferences between hydraulic fractures and the open-hole segments, resulting in significant errors in calculation results. In this article, a novel productivity prediction model for gas reservoirs with open-hole multi-fractured horizontal wells was proposed based on complex potential theories, potential superimposition, and numerical analysis. Herein, an open-hole segment between two adjacent fractures was regarded as an equivalent fracture, which was discretized as in cases of artificial fractures. The proposed model was then applied to investigate the effects of various parameters, such as the angle between the fracture and horizontal shaft, fracture quantity, fracture length, diversion capacity of fractures, horizontal well length, and inter-fracture distance, on the productivity of low permeability gas reservoirs with multi-fractured horizontal wells. Simulation results revealed that the quantity, length, and distribution of fractures had significant effects on the productivity of low permeability gas reservoirs while the effects of the diversion capacity of fractures and the angle between the fracture and horizontal shaft were negligible. Additionally, a U-shaped distribution of fracture lengths was preferential as the quantity of fractures at shaft ends was twice that in the middle area. Keywords: Low permeability gas reservoir, Multi-fractured horizontal well, Productivity prediction, Open-hole completion, Unsteady-state flow, Fracture parameters optimization

  8. A characteristics of East Asian climate using high-resolution regional climate model

    Science.gov (United States)

    Yhang, Y.

    2013-12-01

    Climate research, particularly application studies for water, agriculture, forestry, fishery and energy management require fine scale multi-decadal information of meteorological, oceanographic and land states. Unfortunately, spatially and temporally homogeneous multi-decadal observations of these variables in high horizontal resolution are non-existent. Some long term surface records of temperature and precipitation exist, but the number of observation is very limited and the measurements are often contaminated by changes in instrumentation over time. Some climatologically important variables, such as soil moisture, surface evaporation, and radiation are not even measured over most of East Asia. Reanalysis is one approach to obtaining long term homogeneous analysis of needed variables. However, the horizontal resolution of global reanalysis is of the order of 100 to 200 km, too coarse for many application studies. Regional climate models (RCMs) are able to provide valuable regional finescale information, especially in regions where the climate variables are strongly regulated by the underlying topography and the surface heterogeneity. In this study, we will provide accurately downscaled regional climate over East Asia using the Global/Regional Integrated Model system [GRIMs; Hong et al. 2013]. A mixed layer model is embedded within the GRIMs in order to improve air-sea interaction. A detailed description of the characteristics of the East Asian summer and winter climate will be presented through the high-resolution numerical simulations. The increase in horizontal resolution is expected to provide the high-quality data that can be used in various application areas such as hydrology or environmental model forcing.

  9. The ground surface energy balance in modelling horizontal ground heat exchangers

    Science.gov (United States)

    Bortoloni, M.; Bottarelli, M.; Su, Y.

    2017-01-01

    The performance of horizontal ground heat exchangers (HGHEs) is strongly dependent on climatic conditions, due to the low installation depth. In numerical modelling of HGHEs, the estimation of shallow soil temperature distribution is a key issue, therefore the boundary condition (BC) at the ground surface should be assigned carefully. With this in mind, a model of the energy balance at the ground surface (GSEB), based on weather variables, was developed. The model was tested as the 3rd kind BC at ground surface in modelling HGHEs by means of the FEM code Comsol Multiphysics, solving the unsteady heat transfer problem in a 2D domain. The GSEB model was calibrated and validated with the observed soil temperature at different depths. In addition, the effect on numerical solutions of different BCs, when assigned at the ground surface, was analysed. Three different simulations were carried out applying the GSEB model, the equivalent surface heat flux and temperature as boundary conditions of the 1st, 2nd and 3rd kind, respectively. The results of this study indicate that the use of the GSEB model is a preferable approach to the problem and that the use of the equivalent surface temperature can be considered as a reasonable simplification.

  10. Minnesota Digital Elevation Model - Tiled 93 Meter Resolution

    Data.gov (United States)

    Minnesota Department of Natural Resources — Digital Elevation Model (DEM) at a resolution of 93 meters. Original data resolution was 3 arc seconds which corresponds (approximately) to a matrix of points at a...

  11. Optimization of Multi-Cluster Fracturing Model under the Action of Induced Stress in Horizontal Wells

    Directory of Open Access Journals (Sweden)

    Shanyong Liu

    2016-05-01

    Full Text Available Volume fracturing in shale gas forms complex fracture networks and increases stimulated reservoir volume through large-scale fracturing operation with plug-perforation technology. However, some perforation clusters are stimulated unevenly after fracturing. This study aims to solve this problem by analyzing the shortcomings of the conventional fracturing model and developing a coupled model based on the 2D fracture motion equation, energy conservation law, linear elastic mechanics, and stress superposition principle. First, a multi-fracture in-situ stress model was built by studying the induced stress produced by the fracture initiation to deduce the multi-fracture induced stress impact factor on the basis of the stress superposition principle. Then, the classical Perkins–Kern–Nordgren model was utilized with the crustal stress model. Finally, a precise fracturing design method was used to optimize perforation and fracturing parameters under the new model. Results demonstrate that the interference effect among fractures is the major factor causing the non-uniform propagation of each fracture. Compression on the main horizontal stress increases the net pressure. Therefore, both the degree of operation difficulty and the complexity of fracture geometry are improved. After applying the optimal design, the production is increased by 20%, and the cost is reduced by 15%.

  12. Modeling horizontal gene transfer (HGT in the gut of the Chagas disease vector Rhodnius prolixus

    Directory of Open Access Journals (Sweden)

    Durvasula Ravi V

    2011-05-01

    Full Text Available Abstract Background Paratransgenesis is an approach to reducing arthropod vector competence using genetically modified symbionts. When applied to control of Chagas disease, the symbiont bacterium Rhodococcus rhodnii, resident in the gut lumen of the triatomine vector Rhodnius prolixus (Hemiptera: Reduviidae, is transformed to export cecropin A, an insect immune peptide. Cecropin A is active against Trypanosoma cruzi, the causative agent of Chagas disease. While proof of concept has been achieved in laboratory studies, a rigorous and comprehensive risk assessment is required prior to consideration of field release. An important part of this assessment involves estimating probability of transgene horizontal transfer to environmental organisms (HGT. This article presents a two-part risk assessment methodology: a theoretical model predicting HGT in the gut of R. prolixus from the genetically transformed symbiont R. rhodnii to a closely related non-target bacterium, Gordona rubropertinctus, in the absence of selection pressure, and a series of laboratory trials designed to test the model. Results The model predicted an HGT frequency of less than 1.14 × 10-16 per 100,000 generations at the 99% certainty level. The model was iterated twenty times, with the mean of the ten highest outputs evaluated at the 99% certainty level. Laboratory trials indicated no horizontal gene transfer, supporting the conclusions of the model. Conclusions The model treats HGT as a composite event, the probability of which is determined by the joint probability of three independent events: gene transfer through the modalities of transformation, transduction, and conjugation. Genes are represented in matrices and Monte Carlo method and Markov chain analysis are used to simulate and evaluate environmental conditions. The model is intended as a risk assessment instrument and predicts HGT frequency of less than 1.14 × 10-16 per 100,000 generations. With laboratory studies that

  13. Modeling of sand-water slurry flow through horizontal pipe using CFD

    Directory of Open Access Journals (Sweden)

    Kumar Gopaliya Manoj

    2016-09-01

    Full Text Available The paper presents three-dimensional CFD analysis of two-phase (sand-water slurry flows through 263 mm diameter pipe in horizontal orientation for mixture velocity range of 3.5-4.7 m/s and efflux concentration range of 9.95-34% with three particle sizes viz. 0.165 mm, 0.29 mm and 0.55 mm with density 2650 kg/m3. RNG k-ε turbulence closure equations with Eulerian multi-phase model is used to simulate various slurry flows. The simulated values of local solid concentration are compared with the experimental data and are found to be in good agreement for all particle sizes. Effects of particle size on various slurry flow parameters such as pressure drop, solid phase velocity distribution, friction factor, granular pressure, turbulent viscosity, turbulent kinetic energy and its dissipation have been analyzed.

  14. Economic Integration and Quality Standards in a Duopoly Model with Horizontal and Vertical Product Differentiation

    DEFF Research Database (Denmark)

    Hansen, Jørgen Drud; Nielsen, Jørgen Ulff-Møller

    2006-01-01

    This paper examines the effects of trade barriers on quality levels in a duopoly model for two countries with one producer in each country. The products are both vertically and horizontally differentiated. In absence of quality regulation, the two producers determine prices and quality levels...... product. On the unregulated markets, integration increases welfare in both countries if they are almost of similar size. However, if the countries are very asymmetrical with respect to size, market integration may harm welfare in the large country. Welfare effects by introduction of minimum quality...... in a two stage game. The firms choose the quality level in the first game, and their prices in the second game. The Nash equilibrium illustrates that the producer in the large country produces a higher quality than the producer in the small country. However, a reduction of the trade barrier twists...

  15. Implementing Problem Resolution Models in Remedy

    CERN Document Server

    Marquina, M A; Ramos, R

    2000-01-01

    This paper defines the concept of Problem Resolution Model (PRM) and describes the current implementation made by the User Support unit at CERN. One of the main challenges of User Support services in any High Energy Physics institute/organization is to address solving of the computing-relatedproblems faced by their researchers. The User Support group at CERN is the IT unit in charge of modeling the operations of the Help Desk and acts as asecond level support to some of the support lines whose problems are receptioned at the Help Desk. The motivation behind the use of a PRM is to provide well defined procedures and methods to react in an efficient way to a request for solving a problem,providing advice, information etc. A PRM is materialized on a workflow which has a set of defined states in which a problem can be. Problems move from onestate to another according to actions as decided by the person who is handling them. A PRM can be implemented by a computer application, generallyreferred to as Problem Report...

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

    Directory of Open Access Journals (Sweden)

    Michael S. Okundamiya

    2013-10-01

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

  17. A Mathematical Pressure Transient Analysis Model for Multiple Fractured Horizontal Wells in Shale Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Yan Zeng

    2018-01-01

    Full Text Available Multistage fractured horizontal wells (MFHWs have become the main technology for shale gas exploration. However, the existing models have neglected the percolation mechanism in nanopores of organic matter and failed to consider the differences among the reservoir properties in different areas. On that account, in this study, a modified apparent permeability model was proposed describing gas flow in shale gas reservoirs by integrating bulk gas flow in nanopores and gas desorption from nanopores. The apparent permeability was introduced into the macroseepage model to establish a dynamic pressure analysis model for MFHWs dual-porosity formations. The Laplace transformation and the regular perturbation method were used to obtain an analytical solution. The influences of fracture half-length, fracture permeability, Langmuir volume, matrix radius, matrix permeability, and induced fracture permeability on pressure and production were discussed. Results show that fracture half-length, fracture permeability, and induced fracture permeability exert a significant influence on production. A larger Langmuir volume results in a smaller pressure and pressure derivative. An increase in matrix permeability increases the production rate. Besides, this model fits the actual field data relatively well. It has a reliable theoretical foundation and can preferably describe the dynamic changes of pressure in the exploration process.

  18. Global spatially explicit CO2 emission metrics at 0.25° horizontal resolution for forest bioenergy

    Science.gov (United States)

    Cherubini, F.

    2015-12-01

    Bioenergy is the most important renewable energy option in studies designed to align with future RCP projections, reaching approximately 250 EJ/yr in RCP2.6, 145 EJ/yr in RCP4.5 and 180 EJ/yr in RCP8.5 by the end of the 21st century. However, many questions enveloping the direct carbon cycle and climate response to bioenergy remain partially unexplored. Bioenergy systems are largely assessed under the default climate neutrality assumption and the time lag between CO2 emissions from biomass combustion and CO2 uptake by vegetation is usually ignored. Emission metrics of CO2 from forest bioenergy are only available on a case-specific basis and their quantification requires processing of a wide spectrum of modelled or observed local climate and forest conditions. On the other hand, emission metrics are widely used to aggregate climate impacts of greenhouse gases to common units such as CO2-equivalents (CO2-eq.), but a spatially explicit analysis of emission metrics with global forest coverage is today lacking. Examples of emission metrics include the global warming potential (GWP), the global temperature change potential (GTP) and the absolute sustained emission temperature (aSET). Here, we couple a global forest model, a heterotrophic respiration model, and a global climate model to produce global spatially explicit emission metrics for CO2 emissions from forest bioenergy. We show their applications to global emissions in 2015 and until 2100 under the different RCP scenarios. We obtain global average values of 0.49 ± 0.03 kgCO2-eq. kgCO2-1 (mean ± standard deviation), 0.05 ± 0.05 kgCO2-eq. kgCO2-1, and 2.14·10-14 ± 0.11·10-14 °C (kg yr-1)-1, and 2.14·10-14 ± 0.11·10-14 °C (kg yr-1)-1 for GWP, GTP and aSET, respectively. We also present results aggregated at a grid, national and continental level. The metrics are found to correlate with the site-specific turnover times and local climate variables like annual mean temperature and precipitation. Simplified

  19. Sensitivities of the hydrologic cycle to model physics, grid resolution, and ocean type in the aquaplanet Community Atmosphere Model

    Science.gov (United States)

    Benedict, James J.; Medeiros, Brian; Clement, Amy C.; Pendergrass, Angeline G.

    2017-06-01

    Precipitation distributions and extremes play a fundamental role in shaping Earth's climate and yet are poorly represented in many global climate models. Here, a suite of idealized Community Atmosphere Model (CAM) aquaplanet simulations is examined to assess the aquaplanet's ability to reproduce hydroclimate statistics of real-Earth configurations and to investigate sensitivities of precipitation distributions and extremes to model physics, horizontal grid resolution, and ocean type. Little difference in precipitation statistics is found between aquaplanets using time-constant sea-surface temperatures and those implementing a slab ocean model with a 50 m mixed-layer depth. In contrast, CAM version 5.3 (CAM5.3) produces more time mean, zonally averaged precipitation than CAM version 4 (CAM4), while CAM4 generates significantly larger precipitation variance and frequencies of extremely intense precipitation events. The largest model configuration-based precipitation sensitivities relate to choice of horizontal grid resolution in the selected range 1-2°. Refining grid resolution has significant physics-dependent effects on tropical precipitation: for CAM4, time mean zonal mean precipitation increases along the Equator and the intertropical convergence zone (ITCZ) narrows, while for CAM5.3 precipitation decreases along the Equator and the twin branches of the ITCZ shift poleward. Increased grid resolution also reduces light precipitation frequencies and enhances extreme precipitation for both CAM4 and CAM5.3 resulting in better alignment with observational estimates. A discussion of the potential implications these hydrologic cycle sensitivities have on the interpretation of precipitation statistics in future climate projections is also presented.Plain Language SummaryPrecipitation plays a fundamental role in shaping Earth's climate. Global climate models predict the average precipitation reasonably well but often struggle to accurately represent how often it

  20. Validation of the Beddoes-Leishman Dynamic Stall Model for Horizontal Axis Wind Turbines using MEXICO data

    NARCIS (Netherlands)

    Pereira, R.; Schepers, G.; Pavel, M.D.

    2011-01-01

    The aim of this study is to assess the load predicting capability of a classical Beddoes-Leishman dynamic stall model in a horizontal axis wind turbine (HAWT) environment, in the presence of yaw-misalignment. The dynamic stall model was tailored to the HAWT environment, and validated against

  1. Regional Quasi-Three-Dimensional Unsaturated-Saturated Water Flow Model Based on a Vertical-Horizontal Splitting Concept

    Directory of Open Access Journals (Sweden)

    Yan Zhu

    2016-05-01

    Full Text Available Due to the high nonlinearity of the three-dimensional (3-D unsaturated-saturated water flow equation, using a fully 3-D numerical model is computationally expensive for large scale applications. A new unsaturated-saturated water flow model is developed in this paper based on the vertical/horizontal splitting (VHS concept to split the 3-D unsaturated-saturated Richards’ equation into a two-dimensional (2-D horizontal equation and a one-dimensional (1-D vertical equation. The horizontal plane of average head gradient in the triangular prism element is derived to split the 3-D equation into the 2-D equation. The lateral flow in the horizontal plane of average head gradient represented by the 2-D equation is then calculated by the water balance method. The 1-D vertical equation is discretized by the finite difference method. The two equations are solved simultaneously by coupling them into a unified nonlinear system with a single matrix. Three synthetic cases are used to evaluate the developed model code by comparing the modeling results with those of Hydrus1D, SWMS2D and FEFLOW. We further apply the model to regional-scale modeling to simulate groundwater table fluctuations for assessing the model applicability in complex conditions. The proposed modeling method is found to be accurate with respect to measurements.

  2. High-resolution DEM Effects on Geophysical Flow Models

    Science.gov (United States)

    Williams, M. R.; Bursik, M. I.; Stefanescu, R. E. R.; Patra, A. K.

    2014-12-01

    Geophysical mass flow models are numerical models that approximate pyroclastic flow events and can be used to assess the volcanic hazards certain areas may face. One such model, TITAN2D, approximates granular-flow physics based on a depth-averaged analytical model using inputs of basal and internal friction, material volume at a coordinate point, and a GIS in the form of a digital elevation model (DEM). The volume of modeled material propagates over the DEM in a way that is governed by the slope and curvature of the DEM surface and the basal and internal friction angles. Results from TITAN2D are highly dependent upon the inputs to the model. Here we focus on a single input: the DEM, which can vary in resolution. High resolution DEMs are advantageous in that they contain more surface details than lower-resolution models, presumably allowing modeled flows to propagate in a way more true to the real surface. However, very high resolution DEMs can create undesirable artifacts in the slope and curvature that corrupt flow calculations. With high-resolution DEMs becoming more widely available and preferable for use, determining the point at which high resolution data is less advantageous compared to lower resolution data becomes important. We find that in cases of high resolution, integer-valued DEMs, very high-resolution is detrimental to good model outputs when moderate-to-low (solutions for rectification of the problem.

  3. Population-Dynamic Modeling of Bacterial Horizontal Gene Transfer by Natural Transformation.

    Science.gov (United States)

    Mao, Junwen; Lu, Ting

    2016-01-05

    Natural transformation is a major mechanism of horizontal gene transfer (HGT) and plays an essential role in bacterial adaptation, evolution, and speciation. Although its molecular underpinnings have been increasingly revealed, natural transformation is not well characterized in terms of its quantitative ecological roles. Here, by using Neisseria gonorrhoeae as an example, we developed a population-dynamic model for natural transformation and analyzed its dynamic characteristics with nonlinear tools and simulations. Our study showed that bacteria capable of natural transformation can display distinct population behaviors ranging from extinction to coexistence and to bistability, depending on their HGT rate and selection coefficient. With the model, we also illustrated the roles of environmental DNA sources-active secretion and passive release-in impacting population dynamics. Additionally, by constructing and utilizing a stochastic version of the model, we examined how noise shapes the steady and dynamic behaviors of the system. Notably, we found that distinct waiting time statistics for HGT events, namely a power-law distribution, an exponential distribution, and a mix of the both, are associated with the dynamics in the regimes of extinction, coexistence, and bistability accordingly. This work offers a quantitative illustration of natural transformation by revealing its complex population dynamics and associated characteristics, therefore advancing our ecological understanding of natural transformation as well as HGT in general. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. Experimental modelling and CFD simulation of air/water flow in a horizontal channel

    International Nuclear Information System (INIS)

    Thomas Hoehne; Christophe Vallee

    2005-01-01

    Full text of publication follows: For the investigation of air/water slug flow, a horizontal channel with rectangular cross-section was build at Forschungszentrum Rossendorf. The channel allows the investigation of air/water co- and counter current flows under atmospheric pressure, especially the slug behaviour. Optical measurements were performed with a high-speed camera, and were complemented by simultaneous dynamical pressure measurements. CFD simulation of the stratified co-current flow was performed using the code CFX-5 applying the two fluid model with the free surface option. The grid contains 100000 control volumes. The turbulence was modeled separately for each phase using the k, ω-turbulence model. The results show wave formation up to slug development with closure of the whole channel cross section, where the slug is propagating towards the outlet of the channel with an increasing speed compared to the water velocity and an increase of the pressure level in the channel after the slug front. The qualitative slug formation in the CFX calculation is in good agreement with the experiment, while the calculated pressure distribution shows higher peak values than the measured one. (authors)

  5. Mathematical model of the crystallizing blank`s thermal state at the horizontal continuous casting machine

    Directory of Open Access Journals (Sweden)

    Kryukov Igor Yu.

    2017-01-01

    Full Text Available Present article is devoted to the development of the mathematical model, which describes thermal state and crystallization process of the rectangular cross-section blank while continious process of extraction from a horysontal continious casting machine (HCCM.The developed model took cue for the heat-transfer properties of non-iron metal teeming; its temperature on entry to the casting mold; cooling conditions of blank in the carbon molds in the presence of a copper water cooler. Besides, has been considered the asymmetry of heat interchange from blank`s head and drag at mold, coming out from fluid contraction and features of the horizontal casting mold. The developed mathematical model allows to determine alterations in crystallizing blank of the following factors with respect to time: temperature pattern of crystallizing blank under different technical working regimes of HCCM; boundaries of solid two-phase field and liquid two-phase filed; blank`s thickness variation under shrinkage of the ingot`s material

  6. Investigating the northern Adriatic Sea ecosystem state with a very high resolution model

    Science.gov (United States)

    Mattia, Gelsomina; Zavatarelli, Marco; Lovato, Tomas

    2015-04-01

    The northern Adriatic Sea ecosystem dynamics is simulated using the coupling of the BFM (Biogeochemical Flux Model) with the NEMO (Nucleus for European Models of the Ocean) model. The modeling system is implemented at very high horizontal (~800 m) and vertical (95 z-level) resolution and is nested with a coarser scale Adriatic/Mediterranean model. Simulation in hindcast and projection mode are being executed and are aimed to evaluate the ecosystem attributes (vigor, organization, resilience), in order to understand the ecosystem state of the basin with respect to the so-called "Good Ecosystem State" (GES) as defined by the EU-MSF9 Directive. Skill of the model in replicating integrated environmental indices such as the EU-EEACS1023+ is also investigated. Finally the model is also open to an off-line coupling with an higher trophic level (HTL) model.

  7. Simulating the Agulhas system in global ocean models - nesting vs. multi-resolution unstructured meshes

    Science.gov (United States)

    Biastoch, Arne; Sein, Dmitry; Durgadoo, Jonathan V.; Wang, Qiang; Danilov, Sergey

    2018-01-01

    Many questions in ocean and climate modelling require the combined use of high resolution, global coverage and multi-decadal integration length. For this combination, even modern resources limit the use of traditional structured-mesh grids. Here we compare two approaches: A high-resolution grid nested into a global model at coarser resolution (NEMO with AGRIF) and an unstructured-mesh grid (FESOM) which allows to variably enhance resolution where desired. The Agulhas system around South Africa is used as a testcase, providing an energetic interplay of a strong western boundary current and mesoscale dynamics. Its open setting into the horizontal and global overturning circulations also requires global coverage. Both model configurations simulate a reasonable large-scale circulation. Distribution and temporal variability of the wind-driven circulation are quite comparable due to the same atmospheric forcing. However, the overturning circulation differs, owing each model's ability to represent formation and spreading of deep water masses. In terms of regional, high-resolution dynamics, all elements of the Agulhas system are well represented. Owing to the strong nonlinearity in the system, Agulhas Current transports of both configurations and in comparison with observations differ in strength and temporal variability. Similar decadal trends in Agulhas Current transport and Agulhas leakage are linked to the trends in wind forcing.

  8. Modelling of stratified gas-liquid two-phase flow in horizontal circular pipes

    International Nuclear Information System (INIS)

    Sampaio, P.A.B. de; Faccini, J.L.H.; Su, J.

    2006-01-01

    This paper reports numerical and experimental investigation of stratified gas-liquid two-phase flow in horizontal circular pipes. The Reynolds average Navier-Stokes equations (RANS) with κ ω model development stratified gas-liquid two-phase flow are solved by using the finite element methods. A smooth interface surface is assumed without considered the effects of the interfacial waves. The continuity of the shear stress across the interface is enforced with the continuity of the velocity being automatically satisfied by the variational formulation. For it is given position and interface and longitudinal pressure gradient, an inner iteration loop runs to solve nonlinear equations the Newton-Raphson scheme is used to solve the transcendental equations by an outer iteration to determinate the interface position in a 5.2 mm ID circular pipe was measured experimentally by the ultrasonic ultra pulse-echo technique. The numeral were also compared with results in 21 mm ID circular pipe report by Masala (2004). The good agreement between the numerical and experimental results indicates that κ ω model can be applied for the numerical simulation of stratified gas-liquid two phase flow. (author)

  9. The modelling of condensation in horizontal tubes and the comparison with experimental data

    Directory of Open Access Journals (Sweden)

    Bryk Rafał

    2017-01-01

    Full Text Available The condensation in horizontal tubes plays an important role in determining the operation mode of passive safety systems of modern nuclear power plants. In this paper, two different approaches for modelling of this phenomenon are compared and verified against experimental data. The first approach is based on the flow regime map developed by Tandon. Depending on the regime, the heat transfer coefficient is calculated according to corresponding semi-empirical correlation. The second approach uses a general, fully empirical correlation proposed by Shah. Both models are developed with utilization of the object-oriented, equation-based Modelica language and the open-source Open-Modelica environment. The results are compared with data obtained during a large scale integral test, simulating a Loss of Coolant Accident scenario performed at the dedicated Integral Test Facility Karlstein (INKA which was built at the Components Testing Department of AREVA in Karlstein, Germany. The INKA facility was designed to test the performance of the passive safety systems of KERENA, the new AREVA boiling water reactor design. INKA represents the KERENA containment with a volume scaling of 1:24. Components heights and levels over the ground are in the full scale. The comparison of simulations results shows a good agreement.

  10. Modeling and analysis of ORNL horizontal storage tank mobilization and mixing

    International Nuclear Information System (INIS)

    Mahoney, L.A.; Terrones, G.; Eyler, L.L.

    1994-06-01

    The retrieval and treatment of radioactive sludges that are stored in tanks constitute a prevalent problem at several US Department of Energy sites. The tanks typically contain a settled sludge layer with non-Newtonian rheological characteristics covered by a layer of supernatant. The first step in retrieval is the mobilization and mixing of the supernatant and sludge in the storage tanks. Submerged jets have been proposed to achieve sludge mobilization in tanks, including the 189 m 3 (50,000 gallon) Melton Valley Storage tanks (MVST) at Oak Ridge National Laboratory (ORNL) and the planned 378 m 3 (100,000 gallon) tanks being designed as part of the MVST Capacity Increase Project (MVST-CIP). This report focuses on the modeling of mixing and mobilization in horizontal cylindrical tanks like those of the MVST design using submerged, recirculating liquid jets. The computer modeling of the mobilization and mixing processes uses the TEMPEST computational fluid dynamics program (Trend and Eyler 1992). The goals of the simulations are to determine under what conditions sludge mobilization using submerged liquid jets is feasible in tanks of this configuration, and to estimate mixing times required to approach homogeneity of the contents

  11. The three-zone composite productivity model for a multi-fractured horizontal shale gas well

    Science.gov (United States)

    Qi, Qian; Zhu, Weiyao

    2018-02-01

    Due to the nano-micro pore structures and the massive multi-stage multi-cluster hydraulic fracturing in shale gas reservoirs, the multi-scale seepage flows are much more complicated than in most other conventional reservoirs, and are crucial for the economic development of shale gas. In this study, a new multi-scale non-linear flow model was established and simplified, based on different diffusion and slip correction coefficients. Due to the fact that different flow laws existed between the fracture network and matrix zone, a three-zone composite model was proposed. Then, according to the conformal transformation combined with the law of equivalent percolation resistance, the productivity equation of a horizontal fractured well, with consideration given to diffusion, slip, desorption, and absorption, was built. Also, an analytic solution was derived, and the interference of the multi-cluster fractures was analyzed. The results indicated that the diffusion of the shale gas was mainly in the transition and Fick diffusion regions. The matrix permeability was found to be influenced by slippage and diffusion, which was determined by the pore pressure and diameter according to the Knudsen number. It was determined that, with the increased half-lengths of the fracture clusters, flow conductivity of the fractures, and permeability of the fracture network, the productivity of the fractured well also increased. Meanwhile, with the increased number of fractures, the distance between the fractures decreased, and the productivity slowly increased due to the mutual interfere of the fractures.

  12. Using terrestrial laser scanning data to drive decimetric resolution urban inundation models

    Science.gov (United States)

    Fewtrell, Timothy; Duncan, Alastair; Horritt, Matthew; Bates, Paul

    2010-05-01

    The availability of LiDAR data has led to the proliferation a wide variety of research streams from DEM segmentation (Mason et al., 2007) to mapping the vertical profile of vegetation (Blair et al., 1999) and floodplain inundation modelling (Bates et al., 2003). As the specifications of LiDAR systems have improved, the vertical accuracy and spatial resolution of airborne systems have increased to ~5-10 cm and ~25 cm respectively (Baltsavias, 1999), giving highly resolved digital surface models (DSMs) of the urban environment (Mason et al., 2007). More recently, terrestrial laser scanners have started to be employed to capture even higher accuracy (i.e. ~1-3cm horizontal resolution) 3D point cloud data for applications in engineering, transportation, urban planning, among others (Lichti et al., 2008). Such very high resolution terrestrial laser scanning data have, however, yet to be used in urban hydraulic models, despite the fact that anecdotal and modelling evidence of the hydraulic process at work during urban floods suggests that features with very small horizontal and vertical length scales (i.e. walls, kerbs, steps, road cambers and storm drains) can have a significant impact on the flow development. In this paper we therefore investigate the potential utility of terrestrial laser scanning data for improving flood risk assessments in urban areas. To do this two key problems have to be dealt with. First, we require methods to process terrestrial laser scanning data in order to extract hydraulically relevant information. As such a number of processing steps are presented and a variety of resolution DEMs are derived. Second, we need to employ highly computationally efficient hydraulic algorithms in order to build models at the scale of the terrestrial laser scanner data and still simulate flows over spatial domains that are not trivially small. In this study, two state-of-the-art numerical models are used to demonstrate complex urban flood flows for pluvial and

  13. Modeling the Test-Retest Statistics of a Localization Experiment in the Full Horizontal Plane.

    Science.gov (United States)

    Morsnowski, André; Maune, Steffen

    2016-10-01

    Two approaches to model the test-retest statistics of a localization experiment basing on Gaussian distribution and on surrogate data are introduced. Their efficiency is investigated using different measures describing directional hearing ability. A localization experiment in the full horizontal plane is a challenging task for hearing impaired patients. In clinical routine, we use this experiment to evaluate the progress of our cochlear implant (CI) recipients. Listening and time effort limit the reproducibility. The localization experiment consists of a 12 loudspeaker circle, placed in an anechoic room, a "camera silens". In darkness, HSM sentences are presented at 65 dB pseudo-erratically from all 12 directions with five repetitions. This experiment is modeled by a set of Gaussian distributions with different standard deviations added to a perfect estimator, as well as by surrogate data. Five repetitions per direction are used to produce surrogate data distributions for the sensation directions. To investigate the statistics, we retrospectively use the data of 33 CI patients with 92 pairs of test-retest-measurements from the same day. The first model does not take inversions into account, (i.e., permutations of the direction from back to front and vice versa are not considered), although they are common for hearing impaired persons particularly in the rear hemisphere. The second model considers these inversions but does not work with all measures. The introduced models successfully describe test-retest statistics of directional hearing. However, since their applications on the investigated measures perform differently no general recommendation can be provided. The presented test-retest statistics enable pair test comparisons for localization experiments.

  14. Assessment of fluid-to-fluid modelling of critical heat flux in horizontal 37-element bundle flows

    International Nuclear Information System (INIS)

    Yang, S.K.

    2006-01-01

    Fluid-to-fluid modelling laws of critical heat flux (CHF) available in the literature were reviewed. The applicability of the fluid-to-fluid modelling laws was assessed using available data ranging from low to high mass fluxes in horizontal 37-element bundles simulating a CANDU fuel string. Correlations consisting of dimensionless similarity groups were derived using modelling fluid data (Freon-12) to predict water CHF data in horizontal 37-element bundles with uniform and non-uniform axial-heat flux distribution (AFD). The results showed that at mass fluxes higher than ∼4,000 kg/m 2 s (water equivalent value), the vertical fluid-to-fluid modelling laws of Ahmad (1973) and Katto (1979) predict water CHF in horizontal 37-element bundles with non-uniform AFD with average errors of 1.4% and 3.0% and RMS errors of 5.9% and 6.1%, respectively. The Francois and Berthoud (2003) fluid-to-fluid modelling law predicts CHF in non-uniformly heated 37-element bundles in the horizontal orientation with an average error of 0.6% and an RMS error of 10.4% over the available range of 2,000 to 6,200 kg/m 2 s. (author)

  15. Diagnostic tools for evaluating quasi-horizontal transport in global-scale chemistry models

    Science.gov (United States)

    Lee, Huikyo; Youn, Daeok; Patten, Kenneth O.; Olsen, Seth C.; Wuebbles, Donald J.

    2012-10-01

    The upper troposphere and lower stratosphere (UTLS) plays an important role in climate and atmospheric chemistry. Despite its importance on the point of causing deep intrusions of tropics originated air into the midlatitudes, the quasi-horizontal transport process in the UTLS, represented by global chemistry-transport models (CTMs) or chemistry-climate models (CCMs), cannot easily be diagnosed with conventional analyses on isobaric surfaces. We use improved diagnostic tools to better evaluate CTMs and CCMs relative to satellite observations in the region of UTLS. Using the Hellinger distance, vertical profiles of probability density functions (PDFs) of chemical tracers simulated by the Model for OZone And Related chemical Tracers 3.1 (MOZART-3.1) are quantitatively compared with satellite data from the Microwave Limb Sounder (MLS) instrument in the tropopause relative altitude coordinate to characterize features of tracer distributions near the tropopause. Overall, the comparison of PDFs between MLS and MOZART-3.1 did not satisfy the same population assumption. Conditional PDFs are used to understand the meteorological differences between global climate models and the real atmosphere and the conditional PDFs between MOZART-3.1 and MLS showed better agreement compared to the original PDFs. The low static stability during high tropopause heights at midlatitudes suggests that the variation of tropopause height is related to transport processes from the tropics to midlatitudes. MOZART-3.1 with the GEOS4 GCM winds reproduces episodes of the tropical air intrusions. However, our diagnostic analyses show that the GEOS4 GCM did not properly reproduce the high tropopause cases at midlatitudes especially in spring.

  16. Global tropospheric ozone modeling: Quantifying errors due to grid resolution

    Science.gov (United States)

    Wild, Oliver; Prather, Michael J.

    2006-06-01

    Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quantifying the errors in regional and global budgets. The sensitivity to vertical mixing through the parameterization of boundary layer turbulence is also examined. We find less ozone production in the boundary layer at higher resolution, consistent with slower chemical production in polluted emission regions and greater export of precursors. Agreement with ozonesonde and aircraft measurements made during the NASA TRACE-P campaign over the western Pacific in spring 2001 is consistently better at higher resolution. We demonstrate that the numerical errors in transport processes on a given resolution converge geometrically for a tracer at successively higher resolutions. The convergence in ozone production on progressing from T21 to T42, T63, and T106 resolution is likewise monotonic but indicates that there are still large errors at 120 km scales, suggesting that T106 resolution is too coarse to resolve regional ozone production. Diagnosing the ozone production and precursor transport that follow a short pulse of emissions over east Asia in springtime allows us to quantify the impacts of resolution on both regional and global ozone. Production close to continental emission regions is overestimated by 27% at T21 resolution, by 13% at T42 resolution, and by 5% at T106 resolution. However, subsequent ozone production in the free troposphere is not greatly affected. We find that the export of short-lived precursors such as NOx by convection is overestimated at coarse resolution.

  17. Sensing Property Modeling for the Novel Horizontal-vertical Composite Underground Displacement Sensor

    OpenAIRE

    Nanying Shentu; Guohua Qiu; Xiong Li; Renyuan Tong; Qing Li

    2014-01-01

    Due to invisibility and complexity of the underground displacement monitoring, there exit few practical monitoring sensors capable of monitoring the underground horizontal and vertical displacements simultaneously. A novel electromagnetic underground displacement sensor able to monitor both the horizontal and the vertical displacements was proposed in our previous studies and abbreviated as the H-V type sensor. Through comprehensive application of Hall sensing mechanism analysis, 3D magnetic ...

  18. New modelling of transient well test and rate decline analysis for a horizontal well in a multiple-zone reservoir

    International Nuclear Information System (INIS)

    Nie, Ren-Shi; Guo, Jian-Chun; Jia, Yong-Lu; Zhu, Shui-Qiao; Rao, Zheng; Zhang, Chun-Guang

    2011-01-01

    The no-type curve with negative skin of a horizontal well has been found in the current research. Negative skin is very significant to transient well test and rate decline analysis. This paper first presents the negative skin problem where the type curves with negative skin of a horizontal well are oscillatory. In order to solve the problem, we propose a new model of transient well test and rate decline analysis for a horizontal well in a multiple-zone composite reservoir. A new dimensionless definition of r D is introduced in the dimensionless mathematical modelling under different boundaries. The model is solved using the Laplace transform and separation of variables techniques. In Laplace space, the solutions for both constant rate production and constant wellbore pressure production are expressed in a unified formula. We provide graphs and thorough analysis of the new standard type curves for both well test and rate decline analysis; the characteristics of type curves are the reflections of horizontal well production in a multiple-zone reservoir. An important contribution of our paper is that our model removed the oscillation in type curves and thus solved the negative skin problem. We also show that the characteristics of type curves depend heavily on the properties of different zones, skin factor, well length, formation thickness, etc. Our research can be applied to a real case study

  19. A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.

    Science.gov (United States)

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

  20. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2011-12-01

    Full Text Available Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

  1. The influence of the solar radiation model on the calcutated solar radiation from a horizontal surface to a tilted surface

    DEFF Research Database (Denmark)

    Andersen, Elsa; Lund, Hans; Furbo, Simon

    2004-01-01

    in the calculation. The weather data are measured at the solar radiation measurement station, SMS at the Department of Civil Engineering at the Technical University of Denmark. In this study the weather data are combined with solar collector calculations based on solar collector test carried out at Solar Energy...... Center, SEC, Denmark. With measured solar radiation on horizontal and the different solar radiation processing models the total radiation is calculated on differently tilted and oriented surfaces and compared with the measured solar radiation on the different surfaces. Further, the impact on the yearly......Measured solar radiation data are most commonly available as total solar radiation on a horizontal surface. When using solar radiation measured on horizontal to calculate the solar radiation on tilted surfaces and thereby the thermal performance of different applications such as buildings and solar...

  2. Analysis of Freight Trip Generation Model for Food and Beverage in Belo Horizonte (Brazil

    Directory of Open Access Journals (Sweden)

    Leise Kelli de Oliveira

    2017-01-01

    Full Text Available Today, one of the main challenges faced in urban logistics is the distribution of goods. In Brazil, mid to large cities have experienced consequences of unplanned urban sprawl and lack of adequate transportation infrastructure. The relationship between urban planning and transport stands out the attractiveness of some urban activities with direct impacts on the movement of people and goods and other component elements of urban space. The segment of bars and restaurants falls within this context, therefore is a vital activity responsible for significant percentage of jobs and revenue in a city. Altogether, foods & beverages commercial activities move daily large volumes of goods to meet the need of customers. This paper presents the results of a freight trip generation model developed for pubs and restaurants in Belo Horizonte (Brazil. Once performed the model determined the number of trips generated per day per establishment. In order to expand the discrete result to a continuous one, the results were geographically interpolated to a continuous surface and extrapolated within the city limits. The data for the freight trip generation model were obtained by survey. For this, we designed a structured questionnaire to obtain information about goods, frequency, operational time, place of performance of the loading/unloading of goods, establishment size and the number of employees. Besides these information, we investigated the acceptance of alternative practices in the delivery of goods, such as off-peak delivery. To accomplish the proposed models, we applied a simple linear regression, correlating the following variables: (i Number of trips versus area of the establishment; (ii Number of trips versus number of employees; (iii Number of trips versus operation day of the establishment. With the results of the linear regression for travel generations, conducted the data interpolation based on the standard deviation of the results to define the sample

  3. Performance and Economic Modeling of Horizontally Drilled Ground-Source Heat Pumps in Select California Climates

    Science.gov (United States)

    Wiryadinata, Steven

    Service life modeling was performed to gage the viability of unitary 3.5 kWt, ground-source terminal heat pumps (GTHP) employing horizontal directionally drilled geothermal heat exchangers (GHX) over air-source terminal heat pumps (PTHP) in hotels and motels and residential apartment building sectors in California's coastal and inland climates. Results suggest the GTHP can reduce hourly peak demand for the utility by 7%-25% compared to PTHP, depending on the climate and building type. The annual energy savings, which range from -1% to 5%, are highly dependent on the GTHP pump energy use relative to the energy savings attributed to the difference in ground and air temperatures (DeltaT). In mild climates with small ?T, the pump energy use may overcome any advantage to utilizing a GHX. The majority of total levelized cost savings - ranging from 0.18/ft2 to 0.3/ft 2 - are due to reduced maintenance and lifetime capital cost normally associated with geothermal heat pump systems. Without these reductions (not validated for the GTHP system studied), the GTHP technology does not appear to offer significant advantages over PTHP in the climate zones studied here. The GTHP levelized cost was most sensitive to variations in installed cost and in some cases, energy use (influenced by climate zone choice), which together highlights the importance of climate selection for installation, and the need for larger market penetration of ground-source systems in order to bring down installed costs as the technology matures.

  4. GPS horizontal deformation model in the southern region of the Iberian Peninsula and northern Africa (SPINA)

    International Nuclear Information System (INIS)

    Rosado Moscoso, B.; Fernández-Ros, A.; Jiménez Jiménez, A.; Berrocoso Domínguez, M.

    2017-01-01

    Global Navigation Satellite System (GNSS), and in particular Global Positioning System (GPS) technology provides a powerful tool for studying geodynamic processes. As a consequence of GPS studies, it is now possible to analyze the interaction between tectonic plates in order to evaluate and establish the characteristics of their boundaries. In this study, our main interest is to focus on the time series analysis obtained from observations of GNSS-GPS satellites. Each GPS observation session provides topocentric geodetic coordinates (east, north, elevation) of the permanent stations that constitute the geodetic network established for this purpose. This paper shows a detailed topocentric coordinate time-series study for sites belonging to what we call the SPINA network, which stands for south of the Iberian Peninsula, north of Africa region. The series under study are processed by techniques of relative positioning with respect to the IGS (International GNSS Service) reference station located in Villafranca. These times series have been analyzed using filter processes, harmonic adjustments and wavelets. A surface velocity field is derived from the time series of daily solutions for each station, whose observations span 8 years or longer. This allows us to obtain a horizontal displacement model to show the regional geodynamic main characteristics. [es

  5. Practical models to estimate horizontal irradiance in clear sky conditions: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, German A.; Hernandez, Alejandro L.; Saravia, Luis R. [Department of Physics, School of Exact Sciences, National University of Salta, Bolivia Avenue 5150, 4400 Salta Capital (Argentina); INENCO (Institute of Non Conventional Energy Research), Bolivia Avenue 5150, 4400 Salta Capital (Argentina)

    2010-11-15

    The Argentinean Northwest (ANW) is a high altitude region located alongside Los Andes Mountains. The ANW is also one of the most insolated regions in the world due to its altitude and particular climate. However, the characterization of the solar resource in the region is incomplete as there are no stations to measure solar radiation continuously and methodically. With irradiance data recently having been measured at three sites in the Salta Province, a study was carried out that resulted in a practical model to quickly and efficiently estimate the horizontal irradiance in high altitude sites in clear sky conditions. This model uses the altitude above sea level (A) as a variable and generates a representative clearness index as a result (k{sub t-R}) that is calculated for each site studied. This index k{sub t-R} is then used with the relative optical air mass and the extraterrestrial irradiance to estimate the instantaneous clearness index (k{sub t}). Subsequently, the index k{sub t-R} is corrected by introducing the atmospheric pressure in the definition of relative optical air mass proposed by Kasten. The results are satisfactory as errors in the irradiance estimations with respect to measured values do not exceed 5% for pressure corrected air masses AM{sub c} < 2. This model will be used in a feasibility study to locate sites for the installation of solar thermal power plants in the ANW. A prototype of a CLFR solar power plant is being built in the INENCO Campus, at the National University of Salta. (author)

  6. A Meteorological Distribution System for High Resolution Terrestrial Modeling (MicroMet)

    Science.gov (United States)

    Liston, G. E.; Elder, K.

    2004-12-01

    Spatially distributed terrestrial models generally require atmospheric forcing data on horizontal grids that are of higher resolution than available meteorological data. Furthermore, the meteorological data collected may not necessarily represent the area of interest's meteorological variability. To address these deficiencies, computationally efficient and physically realistic methods must be developed to take available meteorological data sets (e.g., meteorological tower observations) and generate high-resolution atmospheric-forcing distributions. This poster describes MicroMet, a quasi-physically-based, but simple meteorological distribution model designed to produce high-resolution (e.g., 5-m to 1-km horizontal grid increments) meteorological data distributions required to run spatially distributed terrestrial models over a wide variety of landscapes. The model produces distributions of the seven fundamental atmospheric forcing variables required to run most terrestrial models: air temperature, relative humidity, wind speed, wind direction, incoming solar radiation, incoming longwave radiation, and precipitation. MicroMet includes a preprocessor that analyzes meteorological station data and identifies and repairs potential data deficiencies. The model uses known relationships between meteorological variables and the surrounding area (primarily topography) to distribute those variables over any given landscape. MicroMet performs two kinds of adjustments to available meteorological data: 1) when there are data at more than one location, at a given time, the data are spatially interpolated over the domain using a Barnes objective analysis scheme, and 2) physical sub-models are applied to each MicroMet variable to improve its realism at a given point in space and time with respect to the terrain. The three, 25-km by 25-km, Cold Land Processes Experiment (CLPX) mesoscale study areas (MSAs: Fraser, North Park, and Rabbit Ears) will be used as example Micro

  7. Land use and topography influence in a complex terrain area: A high resolution mesoscale modelling study over the Eastern Pyrenees using the WRF model

    Science.gov (United States)

    Jiménez-Esteve, B.; Udina, M.; Soler, M. R.; Pepin, N.; Miró, J. R.

    2018-04-01

    Different types of land use (LU) have different physical properties which can change local energy balance and hence vertical fluxes of moisture, heat and momentum. This in turn leads to changes in near-surface temperature and moisture fields. Simulating atmospheric flow over complex terrain requires accurate local-scale energy balance and therefore model grid spacing must be sufficient to represent both topography and land-use. In this study we use both the Corine Land Cover (CLC) and United States Geological Survey (USGS) land use databases for use with the Weather Research and Forecasting (WRF) model and evaluate the importance of both land-use classification and horizontal resolution in contributing to successful modelling of surface temperatures and humidities observed from a network of 39 sensors over a 9 day period in summer 2013. We examine case studies of the effects of thermal inertia and soil moisture availability at individual locations. The scale at which the LU classification is observed influences the success of the model in reproducing observed patterns of temperature and moisture. Statistical validation of model output demonstrates model sensitivity to both the choice of LU database used and the horizontal resolution. In general, results show that on average, by a) using CLC instead of USGS and/or b) increasing horizontal resolution, model performance is improved. We also show that the sensitivity to these changes in the model performance shows a daily cycle.

  8. High-resolution urban flood modelling - a joint probability approach

    Science.gov (United States)

    Hartnett, Michael; Olbert, Agnieszka; Nash, Stephen

    2017-04-01

    The hydrodynamic modelling of rapid flood events due to extreme climatic events in urban environment is both a complex and challenging task. The horizontal resolution necessary to resolve complexity of urban flood dynamics is a critical issue; the presence of obstacles of varying shapes and length scales, gaps between buildings and the complex geometry of the city such as slopes affect flow paths and flood levels magnitudes. These small scale processes require a high resolution grid to be modelled accurately (2m or less, Olbert et al., 2015; Hunter et al., 2008; Brown et al., 2007) and, therefore, altimetry data of at least the same resolution. Along with availability of high-resolution LiDAR data and computational capabilities, as well as state of the art nested modelling approaches, these problems can now be overcome. Flooding and drying, domain definition, frictional resistance and boundary descriptions are all important issues to be addressed when modelling urban flooding. In recent years, the number of urban flood models dramatically increased giving a good insight into various modelling problems and solutions (Mark et al., 2004; Mason et al., 2007; Fewtrell et al., 2008; Shubert et al., 2008). Despite extensive modelling work conducted for fluvial (e.g. Mignot et al., 2006; Hunter et al., 2008; Yu and Lane, 2006) and coastal mechanisms of flooding (e.g. Gallien et al., 2011; Yang et al., 2012), the amount of investigations into combined coastal-fluvial flooding is still very limited (e.g. Orton et al., 2012; Lian et al., 2013). This is surprising giving the extent of flood consequences when both mechanisms occur simultaneously, which usually happens when they are driven by one process such as a storm. The reason for that could be the fact that the likelihood of joint event is much smaller than those of any of the two contributors occurring individually, because for fast moving storms the rainfall-driven fluvial flood arrives usually later than the storm surge

  9. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  10. Load Test and Model Calibration of a Horizontally Curved Steel Box-Girder Bridge

    Directory of Open Access Journals (Sweden)

    Freydoon Rezaie

    2015-12-01

    Full Text Available In this paper, full scale load test of a horizontally curved steel box-girder bridge is carried out in order to detect structural defects, which reportedly result in unwanted vibrations in nearby buildings. The bridge is tested under the passage of six heavy vehicles at different speeds, so as to determine its static and dynamic responses. A total number of one hundred and two (102 sensors are used to measure the displacements, strains, and accelerations of different points of the bridge. It is observed that the bridge vibrates at a fundamental frequency of 2.6 Hz intensively and the first mode of vibration is torsional instead of flexural. The dominant frequency of vibration of the nearby buildings is computed to be approximately 2.5Hz using rational formulas. Thus, nearness of the fundamental frequency of the bridge to those of the adjacent buildings may be causing resonance phenomenon. However, in static load tests, low ranges of strain and displacement illustrated adequate structural capacity and appropriate safety under static loads. Numerical models are created using ANSYS and SAP2000 software products, so as to design the loading test and calibrate the finite element models. The connections of the transversal elements to the girders, transversal element spacing, and changes of the stiffness values of the slabs were found to be the most influential issues in the finite elements calibration process. Finally, considering the total damage of all members, the final health score of the bridge was evaluated as 89% indicating that the bridge is in a very good situation.

  11. Global tropospheric ozone modeling: Quantifying errors due to grid resolution

    OpenAIRE

    Wild, Oliver; Prather, Michael J

    2006-01-01

    Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quant...

  12. Modelling horizontal steam generator with ATHLET. Verification of different nodalization schemes and implementation of verified constitutive equations

    Energy Technology Data Exchange (ETDEWEB)

    Beliaev, J.; Trunov, N.; Tschekin, I. [OKB Gidropress (Russian Federation); Luther, W. [GRS Garching (Germany); Spolitak, S. [RNC-KI (Russian Federation)

    1995-12-31

    Currently the ATHLET code is widely applied for modelling of several Power Plants of WWER type with horizontal steam generators. A main drawback of all these applications is the insufficient verification of the models for the steam generator. This paper presents the nodalization schemes for the secondary side of the steam generator, the results of stationary calculations, and preliminary comparisons to experimental data. The consideration of circulation in the water inventory of the secondary side is proved to be necessary. (orig.). 3 refs.

  13. Variable-Resolution Ensemble Climatology Modeling of Sierra Nevada Snowpack within the Community Earth System Model (CESM)

    Science.gov (United States)

    Rhoades, A.; Ullrich, P. A.; Zarzycki, C. M.; Levy, M.; Taylor, M.

    2014-12-01

    Snowpack is crucial for the western USA, providing around 75% of the total fresh water supply (Cayan et al., 1996) and buffering against seasonal aridity impacts on agricultural, ecosystem, and urban water demands. The resilience of the California water system is largely dependent on natural stores provided by snowpack. This resilience has shown vulnerabilities due to anthropogenic global climate change. Historically, the northern Sierras showed a net decline of 50-75% in snow water equivalent (SWE) while the southern Sierras showed a net accumulation of 30% (Mote et al., 2005). Future trends of SWE highlight that western USA SWE may decline by 40-70% (Pierce and Cayan, 2013), snowfall may decrease by 25-40% (Pierce and Cayan, 2013), and more winter storms may tend towards rain rather than snow (Bales et al., 2006). The volatility of Sierran snowpack presents a need for scientific tools to help water managers and policy makers assess current and future trends. A burgeoning tool to analyze these trends comes in the form of variable-resolution global climate modeling (VRGCM). VRGCMs serve as a bridge between regional and global models and provide added resolution in areas of need, eliminate lateral boundary forcings, provide model runtime speed up, and utilize a common dynamical core, physics scheme and sub-grid scale parameterization package. A cubed-sphere variable-resolution grid with 25 km horizontal resolution over the western USA was developed for use in the Community Atmosphere Model (CAM) within the Community Earth System Model (CESM). A 25-year three-member ensemble climatology (1980-2005) is presented and major snowpack metrics such as SWE, snow depth, snow cover, and two-meter surface temperature are assessed. The ensemble simulation is also compared to observational, reanalysis, and WRF model datasets. The variable-resolution model provides a mechanism for reaching towards non-hydrostatic scales and simulations are currently being developed with refined

  14. Dynamics modeling and periodic control of horizontal-axis wind turbines

    Science.gov (United States)

    Stol, Karl Alexander

    2001-07-01

    The development of large multi-megawatt wind turbines has increased the need for active feedback control to meet multiple performance objectives. Power regulation is still of prime concern but there is an increasing interest in mitigating loads for these very large, dynamically soft and highly integrated power systems. This work explores the opportunities for utilizing state space modeling, modal analysis, and multi-objective controllers in advanced horizontal-axis wind turbines. A linear state-space representation of a generic, multiple degree-of-freedom wind turbine is developed to test various control methods and paradigms. The structural model, SymDyn, provides for limited flexibility in the tower, drive train and blades assuming a rigid component architecture with joint springs and dampers. Equations of motion are derived symbolically, verified by numerical simulation, and implemented in the Matlab with Simulink computational environment. AeroDyn, an industry-standard aerodynamics package for wind turbines, provides the aerodynamic load data through interfaced subroutines. Linearization of the structural model produces state equations with periodic coefficients due to the interaction of rotating and non-rotating components. Floquet theory is used to extract the necessary modal properties and several parametric studies identify the damping levels and dominant dynamic coupling influences. Two separate issues of control design are investigated: full-state feedback and state estimation. Periodic gains are developed using time-varying LQR techniques and many different time-invariant control designs are constructed, including a classical PID controller. Disturbance accommodating control (DAC) allows the estimation of wind speed for minimization of the disturbance effects on the system. Controllers are tested in simulation for multiple objectives using measurement of rotor position and rotor speed only and actuation of independent blade pitch. It is found that

  15. The M-2 ocean tide loading wave in Alaska: vertical and horizontal displacements, modelled and observed

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Scherneck, H.G.

    2003-01-01

    Crustal deformations caused by surface load due to ocean tides are strongly dependent on the surface load closest to the observing site. In order to correctly model this ocean loading effect near irregular coastal areas, a high-resolution coastline is required. A test is carried out using two GPS...... sites located in Alaska, where the ocean tide loading effect is large and consequently observed easily by relative positioning with GPS. The selected sites are Fair (Fairbanks) and Chi3 (located on an island that separates Prince William Sound from the Gulf of Alaska). Processing hourly baseline...... solutions between Fair and Chi3 during a period of 49 days yields a significant ocean tide loading effect. The data is processed using different strategies for the tropospheric delay correction. However, the best results are obtained when we use 1-h ZTD (Zenith Tropospheric Delay) parameters for hourly...

  16. An Analytical Model for Simulating Heavy-Oil Recovery by Cyclic Steam Injection Using Horizontal Wells, SUPRI TR-118

    Energy Technology Data Exchange (ETDEWEB)

    Diwan, Utpal; Kovscek, Anthony R.

    1999-08-09

    In this investigation, existing analytical models for cyclic steam injection and oil recovery are reviewed and a new model is proposed that is applicable to horizontal wells. A new flow equation is developed for oil production during cyclic steaming of horizontal wells. The model accounts for the gravity-drainage of oil along the steam-oil interface and through the steam zone. Oil viscosity, effective permeability, geometry of the heated zone, porosity, mobile oil saturation, and thermal diffusivity of the reservoir influence the flow rate of oil in the model. The change in reservoir temperature with time is also modeled, and it results in the expected decline in oil production rate during the production cycle as the reservoir cools. Wherever appropriate, correlations and incorporated to minimize data requirements. A limited comparison to numerical simulation results agrees well, indicating that essential physics are successfully captured. Cyclic steaming appears to be a systematic met hod for heating a cold reservoir provided that a relatively uniform distribution of steam is obtained along the horizontal well during injection. A sensitivity analysis shows that the process is robust over the range of expected physical parameters.

  17. Constructing a multi-sided business model for a smart horizontal IoT service platform

    NARCIS (Netherlands)

    Berkers, F.; Roelands, M.; Bomhof, F.; Bachet, T.; Van Rijn, M.; Koers, W.

    2013-01-01

    In order to realize a viable business ecosystem in the Internet of Things (IoT), we investigated how a smart horizontal IoT service platform can bring value and economies of scale to all required ecosystem stakeholders. By means of an example application domain case, this paper constructs a

  18. High Resolution 3-D Finite-Volume Coastal Ocean Modeling in Lower Campbell River and Discovery Passage, British Columbia, Canada

    Directory of Open Access Journals (Sweden)

    Yuehua Lin

    2014-03-01

    Full Text Available The 3-D unstructured-grid, Finite-Volume Coastal Ocean Model (FVCOM was used to simulate the flows in Discovery Passage including the adjoining Lower Campbell River, British Columbia, Canada. Challenges in the studies include the strong tidal currents (e.g., up to 7.8 m/s in Seymour Narrows and tailrace discharges, small-scale topographic features and steep bottom slopes, and stratification affected by the Campbell River freshwater discharges. Two applications of high resolution 3-D FVCOM modeling were conducted. One is for the Lower Campbell River extending upstream as far as the John Hart Hydroelectric dam. The horizontal resolution varies from 0.27 m to 32 m in the unstructured triangular mesh to resolve the tailrace flow. The bottom elevation decreases ~14 m within the distance of ~1.4 km along the river. This pioneering FVCOM river modeling demonstrated a very good performance in simulating the river flow structures. The second application is to compute ocean currents immediately above the seabed along the present underwater electrical cable crossing routes across Discovery Passage. Higher resolution was used near the bottom with inter-layer spacing ranging from 0.125 to 0.0005 of total water depth. The model behaves very well in simulating the strong tidal currents in the area at high resolution in both the horizontal and vertical. One year maximum near bottom tidal current along the routes was then analyzed using the model results.

  19. Joint analysis of longitudinal feed intake and single recorded production traits in pigs using a novel horizontal model

    DEFF Research Database (Denmark)

    Shirali, M.; Strathe, A. B.; Mark, T.

    2017-01-01

    - and first-order Legendre polynomials of age on test, respectively. The fixed effect and random residual variance were estimated for each weekly FI trait. Residual feed intake (RFI) was derived from the conditional distribution of FI given the breeding values of ADG100 and LMP. The heritability of FI varied......A novel Horizontal model is presented for multitrait analysis of longitudinal traits through random regression analysis combined with single recorded traits. Weekly ADFI on test for Danish Duroc, Landrace, and Yorkshire boars were available from the national test station and were collected from 30...... to 100 kg BW. Single recorded production traits of ADG from birth to 30 kg BW (ADG30), ADG from 30 to 100 kg BW (ADG100), and lean meat percentage (LMP) were available from breeding herds or the national test station. The Horizontal model combined random regression analysis of feed intake (FI...

  20. MODELLING PARTICIPATORY GEOGRAPHIC INFORMATION SYSTEM FOR CUSTOMARY LAND CONFLICT RESOLUTION

    Directory of Open Access Journals (Sweden)

    E. A. Gyamera

    2017-11-01

    Full Text Available Since land contributes to about 73 % of most countries Gross Domestic Product (GDP, attention on land rights have tremendously increased globally. Conflicts over land have therefore become part of the major problems associated with land administration. However, the conventional mechanisms for land conflict resolution do not provide satisfactory result to disputants due to various factors. This study sought to develop a Framework of using Participatory Geographic Information System (PGIS for customary land conflict resolution. The framework was modelled using Unified Modelling Language (UML. The PGIS framework, called butterfly model, consists of three units namely, Social Unit (SU, Technical Unit (TU and Decision Making Unit (DMU. The name butterfly model for land conflict resolution was adopted for the framework based on its features and properties. The framework has therefore been recommended to be adopted for land conflict resolution in customary areas.

  1. PIV and Hotwire Measurement and Analysis of Tip Vortices and Turbulent Wake Generated by a Model Horizontal Axis Wind Turbine

    Science.gov (United States)

    Green, D.; Tan, Y. M.; Chamorro, L. P.; Arndt, R.; Sotiropoulos, F.; Sheng, J.

    2011-12-01

    Understanding vortical flow structures and turbulence in the wake flow behind a Horizontal Axis Wind Turbine (HAWT) has widespread applications in efficient blade design. Moreover, the knowledge of wake-turbine interactions allows us to devise optimal operational parameters, such as the spatial allocation and control algorithms of wind turbines, for a densely populated wind farm. To understand the influence of tip vortices on energy containing mean flow and turbulence, characteristics of vortical structures and turbulence must be quantified thoroughly. In this study, we conduct phase-locked Particle Image Velocimetry (PIV) measurements of the flow before and after a model HAWT, which is located in a zero-pressure gradient wind tunnel with a cross section of 1.7 × 1.7 m and a test section of 16 m in length. A three-blade model HAWT with a diameter of 605 mm and tip-speed ratio of 5 is used. PIV images are recorded by a 2048 × 2048 CCD camera and streamed at 6 Hz continuously; and phased locked with the passage of the blade at its vertical position. Each PIV measurement covers a 0.13 × 0.13 m2 sample area with the spatial resolution of 63 μm and a vector spacing of 0.5 mm. All experiments are conducted at the free-stream wind speed of 10 m/s. Flow fields at thirty consecutive downstream locations up to six rotor diameters and 144 mid chord lengths are measured. At each location, we obtain at least 10,000 instantaneous PIV realizations or 20,000 images. Three different configurations: single, dual, and trio turbines located at 5 rotor diameter upstream to each other, are examined experimentally. The flow statistics include mean wake velocity distributions, characteristics of tip vortices evolving downstream, fluctuation velocity, turbulent kinetic energy, stresses, and energy spectra. We find that tip vortices decay much faster in the wake of the upstream turbines (multiple-turbine configurations), whereas they maintain the coherence and strength behind a single

  2. High resolution experiments with the ALADIN-Climate regional climate model

    Science.gov (United States)

    Csima, G.

    2009-09-01

    The global climate models are able to describe the climate of the Earth at a rather coarse resolution providing realistic projections only for the synoptic scale characteristics of the climate. For this reason, they are insufficient for detailed regional or local scale estimations. However, impact studies and policy makers need simulations including all the effects caused by local features. Consequently, techniques for downscaling global climate model simulations - such as regional climate modelling - are essential. The ALADIN-Climate regional climate model (developed by Météo France on the basis of the internationally developed ALADIN modelling system) was adapted at the Hungarian Meteorological Service a few years ago. In the framework of the CECILIA project (www.cecilia-eu.org), the ALADIN-Climate regional climate model runs at high (10 km) horizontal resolution. Therefore, it is anticipated to give more realistic climate estimation for this century than either the global models or the lower resolution regional climate models. The ALADIN-Climate model was coupled to both ERA-40 re-analysis data and the ARPEGE/OPA global atmosphere-ocean general circulation model for the past - 1961-1990 - as the reference period. For the future time slices of 2021-2050 and 2071-2100, the lateral boundary conditions were provided by the same global model with the use of A1B SRES scenario. The results have been validated against different observational datasets for the past, and have been compared to the results of the ARPEGE-Climat global model in order to expose the added value of the regional climate model. The ALADIN-Climate model has also been evaluated for the future to give an estimation of climate change in the Carpathian Basin.

  3. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    OpenAIRE

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2011-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both h...

  4. A hybrid downscaling using statistical correction and high resolution regional climate model information

    Science.gov (United States)

    Wakazuki, Y.

    2017-12-01

    The author presented the outline of a statistical downscaling method using high resolution regional climate model simulation results, which is called hybrid-downscaling, at AGU fall meeting 2016. This presentation is the extension. The statistical downscaling is calculated with lighter computational costs for various patterns of climate states in future which are needed to estimate uncertainty of regional climate change. However, the estimation accuracy is low in the region where the density of observation is low. On the other hand, dynamical downscaling using regional climate model (RCM) use huge computational costs. However, climatological features are well reproduced even in the region where the density of observation is low. I proposed a method to compensate the disadvantages of statistical and dynamical downscaling methods in the hybrid-downscaling. The downscaling processes are divided into horizontal interpolation (HI) and bias correction (BC). In HI, middle-resolution multi-RCM simulation results are interpolated to high resolution data which has grid sizes of 1-2 km. The HI model for climatological variables such as mean precipitation and temperature is learned by using the high resolution dynamical downscaling result. In BC, correction ratio/difference of high-resolution data are estimated by a generalized linear model with predictors of geographical elements. In this method, spatial distribution is largely influenced by the high-resolution RCM result. The hybrid-downscaling model has been applied for regional climate model simulation with the target region around Japan. Multiple future climate simulations had been performed to cover the uncertainty with 24 and 6 km grid sizes. However, only two climate simulations had been calculated with 2 km grid size because of huge computational costs. To estimate 2 km grid information, two kinds of hybrid-downscaling, in which 24 and 6 km RCM results were used as middle-resolution RCMs, were performed. The

  5. Free fermion resolution of supergroup WZNW models

    Energy Technology Data Exchange (ETDEWEB)

    Quella, T.; Schomerus, V.

    2007-06-15

    Extending our earlier work on PSL(2 vertical stroke 2), we explain how to reduce the solution of WZNW models on general type I supergroups to those defined on the bosonic subgroup. The new analysis covers in particular the supergroups GL(M vertical stroke N) along with several close relatives such as PSL(N vertical stroke N), certain Poincar'e supergroups and the series OSP(2 vertical stroke 2N). This remarkable progress relies on the use of a special Feigin-Fuchs type representation. In preparation for the field theory analysis, we shall exploit a minisuperspace analogue of a free fermion construction to deduce the spectrum of the Laplacian on type I supergroups. The latter is shown to be non-diagonalizable. After lifting these results to the full WZNW model, we address various issues of the field theory, including its modular invariance and the computation of correlation functions. In agreement with previous findings, supergroup WZNW models allow to study chiral and non-chiral aspects of logarithmic conformal field theory within a geometric framework. We shall briefly indicate how insights from WZNW models carry over to non-geometric examples, such as e.g. the W(p) triplet models.

  6. Multi-scale climate modelling over Southern Africa using a variable-resolution global model

    CSIR Research Space (South Africa)

    Engelbrecht, FA

    2011-12-01

    Full Text Available -resolution global simulations, to ultra-high resolution simulations at the micro-scale. The model used for these experiments is a variable-resolution global atmospheric model, the conformal-cubic atmospheric model (CCAM). It is shown that CCAM may be used to obtain...

  7. Horizontal and vertical velocities derived from the IDS contribution to ITRF2014, and comparisons with geophysical models

    Science.gov (United States)

    Moreaux, G.; Lemoine, F. G.; Argus, D. F.; Santamaría-Gómez, A.; Willis, P.; Soudarin, L.; Gravelle, M.; Ferrage, P.

    2016-10-01

    In the context of the 2014 realization of the International Terrestrial Reference Frame, the International DORIS (Doppler Orbitography Radiopositioning Integrated by Satellite) Service (IDS) has delivered to the IERS a set of 1140 weekly SINEX files including station coordinates and Earth orientation parameters, covering the time period from 1993.0 to 2015.0. From this set of weekly SINEX files, the IDS combination centre estimated a cumulative DORIS position and velocity solution to obtain mean horizontal and vertical motion of 160 stations at 71 DORIS sites. The main objective of this study is to validate the velocities of the DORIS sites by comparison with external models or time-series. Horizontal velocities are compared with two recent global plate models (GEODVEL 2010 and NNR-MORVEL56). Prior to the comparisons, DORIS horizontal velocities were corrected for Global Isostatic Adjustment from the ICE-6G (VM5a) model. For more than half of the sites, the DORIS horizontal velocities differ from the global plate models by less than 2-3 mm yr-1. For five of the sites (Arequipa, Dionysos/Gavdos, Manila and Santiago) with horizontal velocity differences with respect to these models larger than 10 mm yr-1, comparisons with GNSS estimates show the veracity of the DORIS motions. Vertical motions from the DORIS cumulative solution are compared with the vertical velocities derived from the latest GPS cumulative solution over the time span 1995.0-2014.0 from the University of La Rochelle solution at 31 co-located DORIS-GPS sites. These two sets of vertical velocities show a correlation coefficient of 0.83. Vertical differences are larger than 2 mm yr-1 at 23 percent of the sites. At Thule, the disagreement is explained by fine-tuned DORIS discontinuities in line with the mass variations of outlet glaciers. Furthermore, the time evolution of the vertical time-series from the DORIS station in Thule show similar trends to the GRACE equivalent water height.

  8. Analysis of condensation on a horizontal cylinder with unknown wall temperature and comparison with the Nusselt model of film condensation

    Science.gov (United States)

    Bahrami, Parviz A.

    1996-01-01

    Theoretical analysis and numerical computations are performed to set forth a new model of film condensation on a horizontal cylinder. The model is more general than the well-known Nusselt model of film condensation and is designed to encompass all essential features of the Nusselt model. It is shown that a single parameter, constructed explicitly and without specification of the cylinder wall temperature, determines the degree of departure from the Nusselt model, which assumes a known and uniform wall temperature. It is also known that the Nusselt model is reached for very small, as well as very large, values of this parameter. In both limiting cases the cylinder wall temperature assumes a uniform distribution and the Nusselt model is approached. The maximum deviations between the two models is rather small for cases which are representative of cylinder dimensions, materials and conditions encountered in practice.

  9. Horizontal shellside thermosiphon reboilers

    International Nuclear Information System (INIS)

    Yilmaz, S.B.

    1987-01-01

    Horizontal shellside thermosiphon reboilers are commonly used in the petroleum processing industries. These units have received very little attention in the literature, and there is no published data for their performance. Due to the lacek of advanced design methods for horizontal thermosiphon reboilers, Heat Transfer Research, Inc. (HTRI) has started a few years ago a comprehensive research program to determine, model and predict the thermal and hydraulic performance of these units. The results of the HTRI research indicates that horizontal thermosiphon reboilers are superior in thermal performance to kettle reboilers and vertical tubeside thermosiphon reboilers. This paper also reviews the state-of-the-art in horizontal thermosiphon reboiler design. Typical design practices and rules-of-thumbs are discussed

  10. High Resolution Lidar Digital Elevation Models and Low Resolution Shaded Relief Maps of Antarctica from USGS, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Lidar high-resolution elevation digital elevation model data and low-resolution shaded relief maps of Antarctica are available for download from the U.S. Antarctic...

  11. Analytical models for lower and upper bounds of the condensation-induced water hammer in long horizontal pipes

    International Nuclear Information System (INIS)

    Chun, Moon Hyun; Park, Joo Wan; Nam, Ho Yun

    1992-01-01

    Improved analytical models have been proposed that can predict the lower and upper limits of the water hammer region for given flow conditions by incorporation of recent advances made in the understanding of phenomena associated with the condensation-induced water hammer into existing methods. Present models are applicable for steam-water counterflow in a long horizontal pipe geometry. Both lower and upper bounds of the water hammer region are expressed in terms of the 'critical inlet water flow rate' as a function of axial position. Water hammer region boundaries predicted by present and typical existing models are compared for particular flow conditions of the water hammer event occurred at San Onofre Unit 1 to assess the applicability of the models examined. The result shows that present models for lower and upper bounds of the water hammer region compare favorably with the best performing existing models

  12. GLOBATO: An enhanced global relief model at 30 arc-seconds resolution

    Science.gov (United States)

    O'Leary, V.; Amante, C.

    2017-12-01

    The National Centers for Environmental Information (NCEI), an office of the National Oceanic and Atmospheric Administration (NOAA), first developed a digital bathymetric and elevation model, ETOPO5, from publicly available data in 1993. For nearly 25 years, NCEI's ETOPO family of global relief models have supported research at a planetary scale, including tsunami forecasting, ocean circulation modeling, visualization of the seafloor, understanding geological phenomena, and aiding the development of other global and regional elevation models. GLOBATO (GLObal BAThymetry and TOpography) is now the most detailed version released by NCEI with a horizontal resolution of 30 arc-seconds and succeeds ETOPO1 with the inclusion of several new or updated data-sets for the seafloor as well as land areas. GLOBATO is a compilation of data derived from models of satellite measurements, ship depth soundings, and multibeam surveys, as well as regional models developed for Greenland and Antarctica. These data were converted from different formats, resolutions, spatial distributions, and projections into a single global model using GDAL v2.2 and MB-System v5.5. As with previous NCEI models, GLOBATO is available in two formats, "bedrock elevation" (measured as the base of major ice sheets) and "ice surface elevation" (measured as the surface of major ice sheets) which provides comprehensive topographic and bathymetric coverage between +- 90 degrees latitude and +- 180 degrees longitude. Adhering to best practices, GLOBATO, all related digital products, and any supporting documentation are available online through the NCEI data portal. These new, high resolution models will better support the variety of research ETOPO1 has made possible.

  13. Experimental contribution to the improvement of horizontal two-phase flow transition modeling

    International Nuclear Information System (INIS)

    Ozturk, O.C.

    2013-01-01

    Several horizontal water-air two-phase adiabatic flows (dispersed bubbly flows and intermittent flows) and their axial evolutions have been studied in the METERO experiment which is consisted of a horizontal circular test section with an internal diameter of 100 mm. Different measurement techniques have been improved and utilized to measure the flow characteristics in order to bring a local description and axial evolution of the flows. The responsible physical mechanisms of the flow regimes and their transitions, particularly the competition between turbulent force and buoyancy force have been explained. The differences between dispersed bubbly flows and intermittent flows have been highlighted and the physical process at the origin of these differences has been explained. Two new dimensionless flow regime maps have been proposed: the first one brings an improvement to the representation of Taitel and Dukler (1976) and proposes new transition criteria. The second novel map takes into account the effects of turbulent and buoyancy forces and the void fraction. (author) [fr

  14. Constraining Stochastic Parametrisation Schemes Using High-Resolution Model Simulations

    Science.gov (United States)

    Christensen, H. M.; Dawson, A.; Palmer, T.

    2017-12-01

    Stochastic parametrisations are used in weather and climate models as a physically motivated way to represent model error due to unresolved processes. Designing new stochastic schemes has been the target of much innovative research over the last decade. While a focus has been on developing physically motivated approaches, many successful stochastic parametrisation schemes are very simple, such as the European Centre for Medium-Range Weather Forecasts (ECMWF) multiplicative scheme `Stochastically Perturbed Parametrisation Tendencies' (SPPT). The SPPT scheme improves the skill of probabilistic weather and seasonal forecasts, and so is widely used. However, little work has focused on assessing the physical basis of the SPPT scheme. We address this matter by using high-resolution model simulations to explicitly measure the `error' in the parametrised tendency that SPPT seeks to represent. The high resolution simulations are first coarse-grained to the desired forecast model resolution before they are used to produce initial conditions and forcing data needed to drive the ECMWF Single Column Model (SCM). By comparing SCM forecast tendencies with the evolution of the high resolution model, we can measure the `error' in the forecast tendencies. In this way, we provide justification for the multiplicative nature of SPPT, and for the temporal and spatial scales of the stochastic perturbations. However, we also identify issues with the SPPT scheme. It is therefore hoped these measurements will improve both holistic and process based approaches to stochastic parametrisation. Figure caption: Instantaneous snapshot of the optimal SPPT stochastic perturbation, derived by comparing high-resolution simulations with a low resolution forecast model.

  15. Climate change evolution of the hydrological balance of the Mediterranean, Black and Caspian Seas: impact of climate model resolution

    Science.gov (United States)

    Elguindi, Nellie; Somot, S.; Déqué, M.; Ludwig, W.

    2011-01-01

    In this study we have evaluated the ability of the CNRM-ARPEGE CLIMATE V4 general circulation model (GCM) to estimate the present-day hydrological budget components [precipitation minus evaporation over the sea ( P - E) and fresh water runoff ( R)] over the Mediterranean, Black and Caspian sea basins. Three simulations were performed which were exactly identical except for horizontal resolution, allowing for a unique opportunity to isolate and study the effects of resolution on simulating the hydrological components. Model calculated values of runoff and P - E were compared to a variety of data sources and show that the model's performance improves significantly with increased resolution, especially in regions with mountainous terrain. Corresponding future climate simulations (following the IPCC A2 scenario) were also performed and indicate that while resolution does not seem to have a significant effect on the qualitative impacts of future climate change on the hydrologic balance, quantitatively the results vary significantly among the models. These results suggests that high resolution global models, or downscaling models such as RCMs, are necessary in order to assess the magnitude of future changes in the hydrological components of these basins.

  16. \\HIGH RESOLUTION 3D MODELING OF THE BEHAIM GLOBE

    Directory of Open Access Journals (Sweden)

    F. Menna

    2012-07-01

    Full Text Available The article describes the 3D surveying and modeling of the Behaim globe, the oldest still existing and intact globe of the earth, preserved at the German National Museum of Nuremberg, Germany. The work is primarily performed using high-resolution digital images and automatic photogrammetric techniques. Triangulation-based laser scanning is also employed to fill some gaps in the derived image-based 3D geometry and perform geometric comparisons. Major problems are encountered in texture mapping. The 3D modeling project and the creation of high-resolution map-projections is performed for scientific, conservation, visualization and education purposes.

  17. THERMOSS: a thermohydraulic model of flow stagnation in a horizontal fuel channel

    International Nuclear Information System (INIS)

    Gulshani, P.; Caplan, M.Z.; Spinks, N.J.

    1984-01-01

    Following a postulated inlet-side small break in the CANDU reactor, emergency coolant is injected to refull the horizontal fuel channels and remove the decay heat. As part of the accident analysis, the effects of loss of forced circulation during the accident are predicted. A break size exists for which, at the end of pump rundown, the break force balances the natural circulation force and the channel flow is reduced to near zero. The subcooled, stagnant channel condition is referred to as the standing-start condition. Subsequently, the channel coolant boils and stratifies. Eventually the steam flow from the channel heats up the endfitting to the saturation temperature and reaches the vertical feeder. The resulting buoyancy-induced flow then refills the channel. One dimensional, two-fluid conservation equations are solved in closed form to predict the duration of stagnation. In this calculation the channel water level is an important intermediate variable because it determines the amount of steam production

  18. Modelling of Heat Transfer Phenomena for Vertical and Horizontal Configurations of In-Pool Condensers and Comparison with Experimental Findings

    Directory of Open Access Journals (Sweden)

    Davide Papini

    2010-01-01

    Different condenser tube arrangements have been developed for applications to the next generation NPPs. The two most used configurations, namely, horizontal and vertical tube condensers, are thoroughly investigated in this paper. Several thermal-hydraulic features were explored, being the analysis mainly devoted to the description of the best-estimate correlations and models for heat transfer coefficient prediction. In spite of a more critical behaviour concerning thermal expansion issues, vertical tube condensers offer remarkably better thermal-hydraulic performances. An experimental validation of the vertical tube correlations is provided by PERSEO facility (SIET labs, Piacenza, showing a fairly good agreement.

  19. Air quality modelling in the Berlin-Brandenburg region using WRF-Chem v3.7.1: sensitivity to resolution of model grid and input data

    Science.gov (United States)

    Kuik, Friderike; Lauer, Axel; Churkina, Galina; Denier van der Gon, Hugo A. C.; Fenner, Daniel; Mar, Kathleen A.; Butler, Tim M.

    2016-12-01

    Air pollution is the number one environmental cause of premature deaths in Europe. Despite extensive regulations, air pollution remains a challenge, especially in urban areas. For studying summertime air quality in the Berlin-Brandenburg region of Germany, the Weather Research and Forecasting Model with Chemistry (WRF-Chem) is set up and evaluated against meteorological and air quality observations from monitoring stations as well as from a field campaign conducted in 2014. The objective is to assess which resolution and level of detail in the input data is needed for simulating urban background air pollutant concentrations and their spatial distribution in the Berlin-Brandenburg area. The model setup includes three nested domains with horizontal resolutions of 15, 3 and 1 km and anthropogenic emissions from the TNO-MACC III inventory. We use RADM2 chemistry and the MADE/SORGAM aerosol scheme. Three sensitivity simulations are conducted updating input parameters to the single-layer urban canopy model based on structural data for Berlin, specifying land use classes on a sub-grid scale (mosaic option) and downscaling the original emissions to a resolution of ca. 1 km × 1 km for Berlin based on proxy data including traffic density and population density. The results show that the model simulates meteorology well, though urban 2 m temperature and urban wind speeds are biased high and nighttime mixing layer height is biased low in the base run with the settings described above. We show that the simulation of urban meteorology can be improved when specifying the input parameters to the urban model, and to a lesser extent when using the mosaic option. On average, ozone is simulated reasonably well, but maximum daily 8 h mean concentrations are underestimated, which is consistent with the results from previous modelling studies using the RADM2 chemical mechanism. Particulate matter is underestimated, which is partly due to an underestimation of secondary organic aerosols

  20. Analysis of Circulation Patterns in the Gulf of Finland, Baltic Sea, Simulated with a High-Resolution Hydrodynamic Model

    Science.gov (United States)

    Westerlund, A.

    2017-12-01

    The Gulf of Finland in the Baltic Sea is a long, estuary-like sea area that is a direct continuation of the Baltic Proper. Short-term surface circulation in the gulf is mainly wind driven. The stability of currents varies from season to season. The relatively large freshwater input from the eastern end and the more saline deep water flow from the main basin at the western end maintain horizontal density gradients. We studied circulation patterns in the gulf with a high-resolution 3D hydrodynamic model setup. The configuration was based on the NEMO model and had 0.25 NM horizontal resolution and vertical resolution of 1 m. Our multi-year simulation revealed high year to year variability in the circulation. The persistency of currents in the Gulf of Finland is known to be low, with high variability in time and space. This was clearly demonstrated by our results. Processes affecting circulation patterns were analysed. These included upwelling-related alongshore currents. Several strong upwelling related coastal currents were present in the results on both northern and southern coast of the Gulf. The effect of wind forcing on the circulation in the gulf was also considered. We analysed wind forcing and found that annual differences contributed to the modelled circulation patterns.

  1. Improving MJO Prediction and Simulation Using AGCM Coupled Ocean Model with Refined Vertical Resolution

    Science.gov (United States)

    Tu, Chia-Ying; Tseng, Wan-Ling; Kuo, Pei-Hsuan; Lan, Yung-Yao; Tsuang, Ben-Jei; Hsu, Huang-Hsiung

    2017-04-01

    Precipitation in Taiwan area is significantly influenced by MJO (Madden-Julian Oscillation) in the boreal winter. This study is therefore conducted by toggling the MJO prediction and simulation with a unique model structure. The one-dimensional TKE (Turbulence Kinetic Energy) type ocean model SIT (Snow, Ice, Thermocline) with refined vertical resolution near surface is able to resolve cool skin, as well as diurnal warm layer. SIT can simulate accurate SST and hence give precise air-sea interaction. By coupling SIT with ECHAM5 (MPI-Meteorology), CAM5 (NCAR) and HiRAM (GFDL), the MJO simulations in 20-yrs climate integrations conducted by three SIT-coupled AGCMs are significant improved comparing to those driven by prescribed SST. The horizontal resolutions in ECHAM5, CAM5 and HiRAM are 2-deg., 1-deg and 0.5-deg., respectively. This suggests that the improvement of MJO simulation by coupling SIT is AGCM-resolution independent. This study further utilizes HiRAM coupled SIT to evaluate its MJO forecast skill. HiRAM has been recognized as one of the best model for seasonal forecasts of hurricane/typhoon activity (Zhao et al., 2009; Chen & Lin, 2011; 2013), but was not as successful in MJO forecast. The preliminary result of the HiRAM-SIT experiment during DYNAMO period shows improved success in MJO forecast. These improvements of MJO prediction and simulation in both hindcast experiments and climate integrations are mainly from better-simulated SST diurnal cycle and diurnal amplitude, which is contributed by the refined vertical resolution near ocean surface in SIT. Keywords: MJO Predictability, DYNAMO

  2. Effect of Leukocyte-Rich and Platelet-Rich Plasma on Healing of a Horizontal Medial Meniscus Tear in a Rabbit Model

    Directory of Open Access Journals (Sweden)

    Kyun Ho Shin

    2015-01-01

    Full Text Available There are limited reports on the effect of platelet-rich plasma (PRP on meniscus healing. The purpose of this study was to investigate the effect of leukocyte-rich PRP (L-PRP on potential healing of the horizontal medial meniscus tears in a rabbit model. A horizontal medial meniscus tear was created in both knees of nine skeletally mature adult rabbits. Left or right knees were randomly assigned to a L-PRP group, or a control group. 0.5 mL of L-PRP from 10 mL of each rabbit’s whole blood was prepared and injected into the horizontal tears in a L-PRP group. None was applied to the horizontal tears in a control group. The histological assessment of meniscus healing was performed at two, four, and six weeks after surgery. We found that there were no significant differences of quantitative histologic scoring between two groups at 2, 4, and 6 weeks after surgery (p>0.05. This study failed to show the positive effect of single injection of L-PRP on enhancing healing of the horizontal medial meniscus tears in a rabbit model. Single injection of L-PRP into horizontal meniscus tears may not effectively enhance healing of horizontal medial meniscus tears.

  3. Problem Resolution through Electronic Mail: A Five-Step Model.

    Science.gov (United States)

    Grandgenett, Neal; Grandgenett, Don

    2001-01-01

    Discusses the use of electronic mail within the general resolution and management of administrative problems and emphasizes the need for careful attention to problem definition and clarity of language. Presents a research-based five-step model for the effective use of electronic mail based on experiences at the University of Nebraska at Omaha.…

  4. Observation and characterization of flow in critical sections of a horizontal pressurized gating system using water models

    Directory of Open Access Journals (Sweden)

    Jaiganesh Venkataramani

    2013-07-01

    Full Text Available This work is concerned with the hydraulics and flow characterization in a pressurized, horizontal gating system with multiple ingates attached to a plate mold, using transparent water models. Runners with two different aspect ratios (w/h = 0.5 and 2 and four different types of ingates (rectangular, convergent, divergent and venturi were examined for their influence on flow behavior. Flow behavior was visualized using a high speed camera capable of capturing images up to 10,000 frames per second. Real time experimentation with a few runner – ingate combinations were carried out to validate the usefulness of water models in predicting the filling behavior. Comparison of the approaches provided useful insights into the filling behavior in critical sections of the flow passages as well as the utility of water models towards understanding of the filling behavior during real time casting.

  5. Modeling Protein Structure at Near Atomic Resolutions With Gorgon

    Science.gov (United States)

    Baker, Matthew L.; Abeysinghe, Sasakthi S.; Schuh, Stephen; Coleman, Ross A.; Abrams, Austin; Marsh, Michael P.; Hryc, Corey F.; Ruths, Troy; Chiu, Wah; Ju, Tao

    2011-01-01

    Electron cryo-microscopy (cryo-EM) has played an increasingly important role in elucidating the structure and function of macromolecular assemblies in near native solution conditions. Typically, however, only non-atomic resolution reconstructions have been obtained for these large complexes, necessitating computational tools for integrating and extracting structural details. With recent advances in cryo-EM, maps at near-atomic resolutions have been achieved for several macromolecular assemblies from which models have been manually constructed. In this work, we describe a new interactive modeling toolkit called Gorgon targeted at intermediate to near-atomic resolution density maps (10-3.5 Å), particularly from cryo-EM. Gorgon's de novo modeling procedure couples sequence-based secondary structure prediction with feature detection and geometric modeling techniques to generate initial protein backbone models. Beyond model building, Gorgon is an extensible interactive visualization platform with a variety of computational tools for annotating a wide variety of 3D volumes. Examples from cryo-EM maps of Rotavirus and Rice Dwarf Virus are used to demonstrate its applicability to modeling protein structure. PMID:21296162

  6. Field Demonstration of Horizontal Infill Drilling Using Cost-effective Integrated Reservoir Modeling--Mississippian Carbonates, Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Saibal Bhattacharya

    2005-08-31

    data constraints afflicting mature Mississippian fields. A publicly accessible databank of representative petrophysical properties and relationships was developed to overcome the paucity of such data that is critical to modeling the storage and flow in these reservoirs. Studies in 3 Mississippian fields demonstrated that traditional reservoir models built by integrating log, core, DST, and production data from existing wells on 40-acre spacings are unable to delineate karst-induced compartments, thus making 3D-seismic data critical to characterize these fields. Special attribute analyses on 3D data were shown to delineate reservoir compartments and predict those with pay porosities. Further testing of these techniques is required to validate their applicability in other Mississippian reservoirs. This study shows that detailed reservoir characterization and simulation on geomodels developed by integrating wireline log, core, petrophysical, production and pressure, and 3D-seismic data enables better evaluation of a candidate field for horizontal infill applications. In addition to reservoir compartmentalization, two factors were found to control the economic viability of a horizontal infill well in a mature Mississippian field: (a) adequate reservoir pressure support, and (b) an average well spacing greater than 40-acres.

  7. Computational Fluid Dynamic Modeling of Horizontal Air-Ground Heat Exchangers (HAGHE for HVAC Systems

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2014-12-01

    Full Text Available In order to satisfy the requirements of Directive 2010/31/EU for Zero Energy Buildings (ZEB, innovative solutions were investigated for building HVAC systems. Horizontal air-ground heat exchangers (HAGHE offer a significant contribution in reducing energy consumption for ventilation, using the thermal energy stored underground, in order to pre-heat or pre-cool the ventilation air, in winter and summer, respectively. This is particularly interesting in applications for industrial, commercial and education buildings where keeping the indoor air quality under control is extremely important. Experimental measurements show that, throughout the year, the outside air temperature fluctuations are mitigated at sufficient ground depth (about 3 m because of the high thermal inertia of the soil, the ground temperature is relatively constant and instead higher than that of the outside air in winter and lower in summer. The study aims to numerically investigate the behavior of HAGHE by varying the air flow rate and soil conductivity in unsteady conditions by using annual weather data of South-East Italy. The analysis shows that, in warm climates, the HAGHE brings a real advantage for only a few hours daily in winter, while it shows significant benefits in the summer for the cooling of ventilation air up to several temperature degrees, already by a short pipe.

  8. The Peano-series solution for modeling shear horizontal waves in piezoelectric plates

    Directory of Open Access Journals (Sweden)

    Ben Ghozlen M.H.

    2012-06-01

    Full Text Available The shear horizontal (SH wave devices have been widely used in electroacoustic. To improve their performance, the phase velocity dispersion and the electromechanical coupling coefficient of the Lamb wave should be calculated exactly in the design. Therefore, this work is to analyze exactly the Lamb waves polarized in the SH direction in homogeneous plate pie.zoelectric material (PZT-5H. An alternative method is proposed to solve the wave equation in such a structure without using the standard method based on the electromechanical partial waves. This method is based on an analytical solution, the matricant explicitly expressed under the Peano series expansion form. Two types of configuration have been addressed, namely the open circuited and the short circuited. Results confirm that the SH wave provides a number of attractive properties for use in sensing and signal processing applications. It has been found that the phase velocity remains nearly constant for all values of h/λ (h is the plate thickness, λ the acoustic wavelength. Secondly the SH0 wave mode can provide very high electromechanical coupling. Graphical representations of electrical and mechanical amounts function of depth are made, they are in agreement with the continuity rules. The developed Peano technique is in agreement with the classical approach, and can be suitable with cylindrical geometry.

  9. Droplet evaporation on a horizontal substrate under gravity field by mesoscopic modeling.

    Science.gov (United States)

    Xie, Chiyu; Zhang, Jianying; Bertola, Volfango; Wang, Moran

    2016-02-01

    The evaporation of water drop deposited on a horizontal substrate is investigated using a lattice Boltzmann method (LBM) for multiphase flows with a large-density ratio. To account for the variation of evaporation flux distribution along the drop interface, a novel evaporation scheme is introduced into the LBM framework, and validated by comparison with experimental data. We aim at discovering the effect of gravity on the evaporating drop in detail, and various evaporation conditions are considered as well as different wetting properties of the substrates. An effective diameter is introduced as an indicator of the critical drop size under which gravity is negligible. Our results show that such critical diameter is much smaller than the capillary length, which has been widely accepted as the critical size in previous and current works. The critical diameter is found to be almost independent of the evaporation conditions and the surface wettability. A correlation between this critical diameter and the capillary length is also proposed for easy use in applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Horizontal rotation of the local stress field in response to magmatic activity: Evidence from case studies and modeling

    Science.gov (United States)

    Roman, D. C.

    2003-12-01

    A complete understanding of the initiation, evolution, and termination of volcanic eruptions requires reliable monitoring techniques to detect changes in the conduit system during periods of activity, as well as corresponding knowledge of conduit structure and of magma physical properties. Case studies of stress field orientation prior to, during, and after magmatic activity can be used to relate changes in stress field orientation to the state of the magmatic conduit system. These relationships may be tested through modeling of induced stresses. Here I present evidence from case studies and modeling that horizontal rotation of the axis of maximum compressive stress at an active volcano indicates pressurization of a magmatic conduit, and that this rotation, when observed, may also be indicative of the physical properties of the ascending magma. Changes in the local stress field orientation during the 1992 eruption sequence at Crater Peak (Mt. Spurr), Alaska were analyzed by calculating and inverting subsets of over 150 fault-plane solutions. Local stress tensors for four time periods, corresponding approximately to changes in activity at the volcano, were calculated based on the misfit of individual fault-plane solutions to a regional stress tensor. Results indicate that for nine months prior to the eruption, local maximum compressive stress was oriented perpendicular to regional maximum compressive stress. A similar horizontal rotation was observed beginning in November of 1992, coincident with an episode of elevated earthquake and tremor activity indicating intrusion of magma into the conduit. During periods of quiescence the local stress field was similar to the regional stress field. Similar horizontal rotations have been observed at Mt. Ruapehu, New Zealand (Miller and Savage 2001, Gerst 2003), Usu Volcano, Japan (Fukuyama et al. 2001), Unzen Volcano, Japan (Umakoshi et al. 2001), and Mt. St. Helens Volcano, USA (Moran 1994) in conjunction with eruptive

  11. Modeled Full-Flight Aircraft Emissions Impacts on Air Quality and Their Sensitivity to Grid Resolution

    Science.gov (United States)

    Vennam, L. P.; Vizuete, W.; Talgo, K.; Omary, M.; Binkowski, F. S.; Xing, J.; Mathur, R.; Arunachalam, S.

    2017-12-01

    Aviation is a unique anthropogenic source with four-dimensional varying emissions, peaking at cruise altitudes (9-12 km). Aircraft emission budgets in the upper troposphere lower stratosphere region and their potential impacts on upper troposphere and surface air quality are not well understood. Our key objective is to use chemical transport models (with prescribed meteorology) to predict aircraft emissions impacts on the troposphere and surface air quality. We quantified the importance of including full-flight intercontinental emissions and increased horizontal grid resolution. The full-flight aviation emissions in the Northern Hemisphere contributed 1.3% (mean, min-max: 0.46, 0.3-0.5 ppbv) and 0.2% (0.013, 0.004-0.02 μg/m3) of total O3 and PM2.5 concentrations at the surface, with Europe showing slightly higher impacts (1.9% (O3 0.69, 0.5-0.85 ppbv) and 0.5% (PM2.5 0.03, 0.01-0.05 μg/m3)) than North America (NA) and East Asia. We computed seasonal aviation-attributable mass flux vertical profiles and aviation perturbations along isentropic surfaces to quantify the transport of cruise altitude emissions at the hemispheric scale. The comparison of coarse (108 × 108 km2) and fine (36 × 36 km2) grid resolutions in NA showed 70 times and 13 times higher aviation impacts for O3 and PM2.5 in coarser domain. These differences are mainly due to the inability of the coarse resolution simulation to capture nonlinearities in chemical processes near airport locations and other urban areas. Future global studies quantifying aircraft contributions should consider model resolution and perhaps use finer scales near major aviation source regions.

  12. A generative model for resolution enhancement of diffusion MRI data.

    Science.gov (United States)

    Yap, Pew-Thian; An, Hongyu; Chen, Yasheng; Shen, Dinggang

    2013-01-01

    The advent of diffusion magnetic resonance imaging (DMRI) presents unique opportunities for the exploration of white matter connectivity in vivo and non-invasively. However, DMRI suffers from insufficient spatial resolution, often limiting its utility to the studying of only major white matter structures. Many image enhancement techniques rely on expensive scanner upgrades and complex time-consuming sequences. We will instead take a post-processing approach in this paper for resolution enhancement of DMRI data. This will allow the enhancement of existing data without re-acquisition. Our method uses a generative model that reflects the image generation process and, after the parameters of the model have been estimated, we can effectively sample high-resolution images from this model. More specifically, we assume that the diffusion-weighted signal at each voxel is an agglomeration of signals from an ensemble of fiber segments that can be oriented and located freely within the voxel. Our model for each voxel therefore consists of an arbitrary number of signal generating fiber segments, and the model parameters that need to be determined are the locations and orientations of these fiber segments. Solving for these parameters is an ill-posed problem. However, by borrowing information from neighboring voxels, we show that this can be solved by using Markov chain Monte Carlo (MCMC) methods such as the Metropolis-Hastings algorithm. Preliminary results indicate that out method substantially increases structural visibility in both subcortical and cortical regions.

  13. Importance of resolution and model configuration when downscaling extreme precipitation

    Directory of Open Access Journals (Sweden)

    Adrian J. Champion

    2014-07-01

    Full Text Available Dynamical downscaling is frequently used to investigate the dynamical variables of extra-tropical cyclones, for example, precipitation, using very high-resolution models nested within coarser resolution models to understand the processes that lead to intense precipitation. It is also used in climate change studies, using long timeseries to investigate trends in precipitation, or to look at the small-scale dynamical processes for specific case studies. This study investigates some of the problems associated with dynamical downscaling and looks at the optimum configuration to obtain the distribution and intensity of a precipitation field to match observations. This study uses the Met Office Unified Model run in limited area mode with grid spacings of 12, 4 and 1.5 km, driven by boundary conditions provided by the ECMWF Operational Analysis to produce high-resolution simulations for the Summer of 2007 UK flooding events. The numerical weather prediction model is initiated at varying times before the peak precipitation is observed to test the importance of the initialisation and boundary conditions, and how long the simulation can be run for. The results are compared to raingauge data as verification and show that the model intensities are most similar to observations when the model is initialised 12 hours before the peak precipitation is observed. It was also shown that using non-gridded datasets makes verification more difficult, with the density of observations also affecting the intensities observed. It is concluded that the simulations are able to produce realistic precipitation intensities when driven by the coarser resolution data.

  14. Comparison of wind and wind shear climatologies derived from high-resolution radiosondes and the ECMWF model

    Science.gov (United States)

    Houchi, K.; Stoffelen, A.; Marseille, G. J.; de Kloe, J.

    2010-11-01

    The climatology of atmospheric horizontal wind and its vertical gradient, i.e., wind shear, is characterized as a function of climate region. For a better representation of the average atmospheric wind and shear and their variabilities, high-resolution radiosonde wind profiles up to about 30 km altitude are compared with the collocated operational ECMWF model for short-range forecast winds. Statistics of zonal and meridional winds are established from both data sets. The results show mainly similarity in the probability distributions of the modeled and observed horizontal winds, practically at all levels of the atmosphere, while at the same time the vertical shear of the wind is substantially underestimated in the model. The comparison of shear statistics of radiosonde and ECMWF model winds shows that the model wind shear mean and variability are on average a factor of 2.5 (zonal) and 3 (meridional) smaller than of radiosondes in the free troposphere, while in the stratosphere, the planetary boundary layer results are more variable. By applying vertical averaging to the radiosonde data, it is found that the effective vertical resolution of the ECMWF model is typically 1.7 km. Moreover, it is found for individually collocated radiosonde model wind and shear profiles that the model wind may lack in some cases variability larger than 5 m s-1 and 0.015 s-1, respectively, due mainly to the effect of lacking vertical resolution, in particular near the jets. Besides the general importance of this study in highlighting the difference in the representation of the atmospheric wind shear by model and observations, it is more specifically relevant for the future Atmospheric Dynamics Mission (ADM-Aeolus) of the European Space Agency due for launch in 2012. The results presented here are used to generate a realistic global atmospheric database, which is necessary to conduct simulations of the Aeolus Doppler wind lidar in order optimize its vertical sampling and processing.

  15. Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO2 emissions

    Directory of Open Access Journals (Sweden)

    S. Feng

    2016-07-01

    Full Text Available Megacities are major sources of anthropogenic fossil fuel CO2 (FFCO2 emissions. The spatial extents of these large urban systems cover areas of 10 000 km2 or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO2 emissions over the Los Angeles (LA megacity area. The Weather Research and Forecasting (WRF-Chem model was coupled to a very high-resolution FFCO2 emission product, Hestia-LA, to simulate atmospheric CO2 concentrations across the LA megacity at spatial resolutions as fine as  ∼  1 km. We evaluated multiple WRF configurations, selecting one that minimized errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May–June 2010. Our results show no significant difference between moderate-resolution (4 km and high-resolution (1.3 km simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution and Hestia-LA (1.3 km resolution fossil fuel CO2 emission products to evaluate the impact of the spatial resolution of the CO2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO2 concentrations. We find that high spatial resolution in the fossil fuel CO2 emissions is more important than in the atmospheric model to capture CO2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO2 fields reflect the coverage of

  16. Nonlinear flow model of multiple fractured horizontal wells with stimulated reservoir volume including the quadratic gradient term

    Science.gov (United States)

    Ren, Junjie; Guo, Ping

    2017-11-01

    The real fluid flow in porous media is consistent with the mass conservation which can be described by the nonlinear governing equation including the quadratic gradient term (QGT). However, most of the flow models have been established by ignoring the QGT and little work has been conducted to incorporate the QGT into the flow model of the multiple fractured horizontal (MFH) well with stimulated reservoir volume (SRV). This paper first establishes a semi-analytical model of an MFH well with SRV including the QGT. Introducing the transformed pressure and flow-rate function, the nonlinear model of a point source in a composite system including the QGT is linearized. Then the Laplace transform, principle of superposition, numerical discrete method, Gaussian elimination method and Stehfest numerical inversion are employed to establish and solve the seepage model of the MFH well with SRV. Type curves are plotted and the effects of relevant parameters are analyzed. It is found that the nonlinear effect caused by the QGT can increase the flow capacity of fluid flow and influence the transient pressure positively. The relevant parameters not only have an effect on the type curve but also affect the error in the pressure calculated by the conventional linear model. The proposed model, which is consistent with the mass conservation, reflects the nonlinear process of the real fluid flow, and thus it can be used to obtain more accurate transient pressure of an MFH well with SRV.

  17. Experimental determination and modelling of interface area concentration in horizontal stratified flow

    International Nuclear Information System (INIS)

    Junqua-Moullet, Alexandra

    2003-01-01

    This research thesis concerns the modelling and experimentation of biphasic liquid/gas flows (water/air) while using the two-fluid model, a six-equation model. The author first addresses the modelling of interfacial magnitudes for a known topology (problem of two-fluid model closure, closure relationships for some variables, equation for a given configuration). She reports the development of an equation system for interfacial magnitudes. The next parts deal with experiments and report the study of stratified flows in the THALC experiment, and more particularly the study of the interfacial area concentration and of the liquid velocities in such flows. Results are discussed, as well as their consistency

  18. High Resolution Global Climate Modeling with GEOS-5: Intense Precipitation, Convection and Tropical Cyclones on Seasonal Time-Scales.

    Science.gov (United States)

    Putnam, WilliamM.

    2011-01-01

    In 2008 the World Modeling Summit for Climate Prediction concluded that "climate modeling will need-and is ready-to move to fundamentally new high-resolution approaches to capitalize on the seamlessness of the weather-climate continuum." Following from this, experimentation with very high-resolution global climate modeling has gained enhanced priority within many modeling groups and agencies. The NASA Goddard Earth Observing System model (GEOS-5) has been enhanced to provide a capability for the execution at the finest horizontal resolutions POS,SIOle with a global climate model today. Using this high-resolution, non-hydrostatic version of GEOS-5, we have developed a unique capability to explore the intersection of weather and climate within a seamless prediction system. Week-long weather experiments, to mUltiyear climate simulations at global resolutions ranging from 3.5- to 14-km have demonstrated the predictability of extreme events including severe storms along frontal systems, extra-tropical storms, and tropical cyclones. The primary benefits of high resolution global models will likely be in the tropics, with better predictions of the genesis stages of tropical cyclones and of the internal structure of their mature stages. Using satellite data we assess the accuracy of GEOS-5 in representing extreme weather phenomena, and their interaction within the global climate on seasonal time-scales. The impacts of convective parameterization and the frequency of coupling between the moist physics and dynamics are explored in terms of precipitation intensity and the representation of deep convection. We will also describe the seasonal variability of global tropical cyclone activity within a global climate model capable of representing the most intense category 5 hurricanes.

  19. Advanced modelling of the transport phenomena across horizontal clothing microclimates with natural convection.

    Science.gov (United States)

    Mayor, T S; Couto, S; Psikuta, A; Rossi, R M

    2015-12-01

    The ability of clothing to provide protection against external environments is critical for wearer's safety and thermal comfort. It is a function of several factors, such as external environmental conditions, clothing properties and activity level. These factors determine the characteristics of the different microclimates existing inside the clothing which, ultimately, have a key role in the transport processes occurring across clothing. As an effort to understand the effect of transport phenomena in clothing microclimates on the overall heat transport across clothing structures, a numerical approach was used to study the buoyancy-driven heat transfer across horizontal air layers trapped inside air impermeable clothing. The study included both the internal flow occurring inside the microclimate and the external flow occurring outside the clothing layer, in order to analyze the interdependency of these flows in the way heat is transported to/from the body. Two-dimensional simulations were conducted considering different values of microclimate thickness (8, 25 and 52 mm), external air temperature (10, 20 and 30 °C), external air velocity (0.5, 1 and 3 m s(-1)) and emissivity of the clothing inner surface (0.05 and 0.95), which implied Rayleigh numbers in the microclimate spanning 4 orders of magnitude (9 × 10(2)-3 × 10(5)). The convective heat transfer coefficients obtained along the clothing were found to strongly depend on the transport phenomena in the microclimate, in particular when natural convection is the most important transport mechanism. In such scenario, convective coefficients were found to vary in wavy-like manner, depending on the position of the flow vortices in the microclimate. These observations clearly differ from data in the literature for the case of air flow over flat-heated surfaces with constant temperature (which shows monotonic variations of the convective heat transfer coefficients, along the length of the surface). The flow

  20. Advanced modelling of the transport phenomena across horizontal clothing microclimates with natural convection

    Science.gov (United States)

    Mayor, T. S.; Couto, S.; Psikuta, A.; Rossi, R. M.

    2015-12-01

    The ability of clothing to provide protection against external environments is critical for wearer's safety and thermal comfort. It is a function of several factors, such as external environmental conditions, clothing properties and activity level. These factors determine the characteristics of the different microclimates existing inside the clothing which, ultimately, have a key role in the transport processes occurring across clothing. As an effort to understand the effect of transport phenomena in clothing microclimates on the overall heat transport across clothing structures, a numerical approach was used to study the buoyancy-driven heat transfer across horizontal air layers trapped inside air impermeable clothing. The study included both the internal flow occurring inside the microclimate and the external flow occurring outside the clothing layer, in order to analyze the interdependency of these flows in the way heat is transported to/from the body. Two-dimensional simulations were conducted considering different values of microclimate thickness (8, 25 and 52 mm), external air temperature (10, 20 and 30 °C), external air velocity (0.5, 1 and 3 m s-1) and emissivity of the clothing inner surface (0.05 and 0.95), which implied Rayleigh numbers in the microclimate spanning 4 orders of magnitude (9 × 102-3 × 105). The convective heat transfer coefficients obtained along the clothing were found to strongly depend on the transport phenomena in the microclimate, in particular when natural convection is the most important transport mechanism. In such scenario, convective coefficients were found to vary in wavy-like manner, depending on the position of the flow vortices in the microclimate. These observations clearly differ from data in the literature for the case of air flow over flat-heated surfaces with constant temperature (which shows monotonic variations of the convective heat transfer coefficients, along the length of the surface). The flow patterns and

  1. PRODUCTIVITY OF FRACTURED HORIZONTAL WELLS

    Directory of Open Access Journals (Sweden)

    Stjepan Antolović

    2009-12-01

    Full Text Available The interest and performance of horizontal drilling and completions has increased during the last two decades. Horizontal wells are advantageous compared to vertical wells in thin reservoirs, reservoirs with favorable vertical permeability and reservoirs with water and gas coning problems. In many reservoirs, the ratio of horizontal permeability to the vertical permeability is substantially larger than one and often is close to 10. Thus, these reservoirs are very good candidates for hydraulic fracturing. By hydraulic fracturing one or more fractures are created, which can be longitudinal or orthogonal. By that, flow is altered and it mostly conducts horizontally through reservoir toward horizontal wellbore. With this altered flow, fluid is produced faster, with less pressure loss by fluid unit of produced fluid. Some of the existing mathematical models to determine the productivity of multifractured horizontal wells are presented in this work (the paper is published in Croatian.

  2. A high resolution hydrodynamic 3-D model simulation of the malta shelf area

    Directory of Open Access Journals (Sweden)

    A. F. Drago

    2003-01-01

    Full Text Available The seasonal variability of the water masses and transport in the Malta Channel and proximity of the Maltese Islands have been simulated by a high resolution (1.6 km horizontal grid on average, 15 vertical sigma layers eddy resolving primitive equation shelf model (ROSARIO-I. The numerical simulation was run with climatological forcing and includes thermohaline dynamics with a turbulence scheme for the vertical mixing coefficients on the basis of the Princeton Ocean Model (POM. The model has been coupled by one-way nesting along three lateral boundaries (east, south and west to an intermediate coarser resolution model (5 km implemented over the Sicilian Channel area. The fields at the open boundaries and the atmospheric forcing at the air-sea interface were applied on a repeating "perpetual" year climatological cycle. The ability of the model to reproduce a realistic circulation of the Sicilian-Maltese shelf area has been demonstrated. The skill of the nesting procedure was tested by model-modelc omparisons showing that the major features of the coarse model flow field can be reproduced by the fine model with additional eddy space scale components. The numerical results included upwelling, mainly in summer and early autumn, along the southern coasts of Sicily and Malta; a strong eastward shelf surface flow along shore to Sicily, forming part of the Atlantic Ionian Stream, with a presence throughout the year and with significant seasonal modulation, and a westward winter intensified flow of LIW centered at a depth of around 280 m under the shelf break to the south of Malta. The seasonal variability in the thermohaline structure of the domain and the associated large-scale flow structures can be related to the current knowledge on the observed hydrography of the area. The level of mesoscale resolution achieved by the model allowed the spatial and temporal evolution of the changing flow patterns, triggered by internal dynamics, to be followed in

  3. A high resolution hydrodynamic 3-D model simulation of the malta shelf area

    Directory of Open Access Journals (Sweden)

    A. F. Drago

    Full Text Available The seasonal variability of the water masses and transport in the Malta Channel and proximity of the Maltese Islands have been simulated by a high resolution (1.6 km horizontal grid on average, 15 vertical sigma layers eddy resolving primitive equation shelf model (ROSARIO-I. The numerical simulation was run with climatological forcing and includes thermohaline dynamics with a turbulence scheme for the vertical mixing coefficients on the basis of the Princeton Ocean Model (POM. The model has been coupled by one-way nesting along three lateral boundaries (east, south and west to an intermediate coarser resolution model (5 km implemented over the Sicilian Channel area. The fields at the open boundaries and the atmospheric forcing at the air-sea interface were applied on a repeating "perpetual" year climatological cycle.

    The ability of the model to reproduce a realistic circulation of the Sicilian-Maltese shelf area has been demonstrated. The skill of the nesting procedure was tested by model-modelc omparisons showing that the major features of the coarse model flow field can be reproduced by the fine model with additional eddy space scale components. The numerical results included upwelling, mainly in summer and early autumn, along the southern coasts of Sicily and Malta; a strong eastward shelf surface flow along shore to Sicily, forming part of the Atlantic Ionian Stream, with a presence throughout the year and with significant seasonal modulation, and a westward winter intensified flow of LIW centered at a depth of around 280 m under the shelf break to the south of Malta. The seasonal variability in the thermohaline structure of the domain and the associated large-scale flow structures can be related to the current knowledge on the observed hydrography of the area. The level of mesoscale resolution achieved by the model allowed the spatial and temporal evolution of the changing flow patterns, triggered by

  4. High resolution topography and land cover databases for wind resource assessment using mesoscale models

    Science.gov (United States)

    Barranger, Nicolas; Stathopoulos, Christos; Kallos, Georges

    2013-04-01

    In wind resource assessment, mesoscale models can provide wind flow characteristics without the use of mast measurements. In complex terrain, local orography and land cover data assimilation are essential parameters to accurately simulate the wind flow pattern within the atmospheric boundary layer. State-of-the-art Mesoscale Models such as RAMS usually provides orography and landuse data with of resolution of 30s (about 1km). This resolution is necessary for solving mesocale phenomena accurately but not sufficient when the aim is to quantitatively estimate the wind flow characteristics passing over sharp hills or ridges. Furthermore, the abrupt change in land cover characterization is nor always taken into account in the model with a low resolution land use database. When land cover characteristics changes dramatically, parameters such as roughness, albedo or soil moisture that can highly influence the Atmospheric Boundary Layer meteorological characteristics. Therefore they require to be accurately assimilated into the model. Since few years, high resolution databases derived from satellite imagery (Modis, SRTM, LandSat, SPOT ) are available online. Being converted to RAMS requirements inputs, an evaluation of the model requires to be achieved. For this purpose, three new high resolution land cover and two topographical databases are implemented and tested in RAMS. The analysis of terrain variability is performed using basis functions of space frequency and amplitude. Practically, one and two dimension Fast Fourier Transform is applied to terrain height to reveal the main characteristics of local orography according to the obtained wave spectrum. By this way, a comparison between different topographic data sets is performed, based on the terrain power spectrum entailed in the terrain height input. Furthermore, this analysis is a powerful tool in the determination of the proper horizontal grid resolution required to resolve most of the energy containing spectrum

  5. Estuarine modeling: Does a higher grid resolution improve model performance?

    Science.gov (United States)

    Ecological models are useful tools to explore cause effect relationships, test hypothesis and perform management scenarios. A mathematical model, the Gulf of Mexico Dissolved Oxygen Model (GoMDOM), has been developed and applied to the Louisiana continental shelf of the northern ...

  6. Towards a 1km resolution global flood risk model

    Science.gov (United States)

    Bates, Paul; Neal, Jeff; Sampson, Chris; Smith, Andy

    2014-05-01

    Recent advances in computationally efficient numerical algorithms and new High Performance Computing architectures now make high (1-2km) resolution global hydrodynamic models a realistic proposition. However in many areas of the world the data sets and tools necessary to undertake such modelling do not currently exist. In particular, five major problems need to be resolved: (1) the best globally available terrain data (SRTM) was generated from X-band interferometric radar data which does not penetrate vegetation canopies and which has significant problems in determining ground elevations in urban areas; (2) a global river bathymetry data set does not currently exist; (3) most river channels globally are less than the smallest currently resolvable grid scale (1km) and therefore require a sub-grid treatment; (4) a means to estimate the magnitude of the T year flood at any point along the global river network does not currently exist; and (5) a large proportion of flood losses are generated by off-floodplain surface water flows which are not well represented in current hydrodynamic modelling systems. In this paper we propose solutions to each of these five issues as part of a concerted effort to develop a 1km (or better) resolution global flood hazard model. We describe the new numerical algorithms, computer architectures and computational resources used, and demonstrate solutions to the five previously intractable problems identified above. We conduct a validation study of the modelling against satellite imagery of major flooding on the Mississippi-Missouri confluence plain in the central USA before outlining a proof-of-concept regional study for SE Asia as a step towards a global scale model. For SE Asia we simulate flood hazard for ten different flood return periods over the entire Thailand, Cambodia, Vietnam, Malaysia and Laos region at 1km resolution and show that the modelling produces coherent, consistent and sensible simulations of extent and water depth.

  7. Crack growth rate in core shroud horizontal welds using two models for a BWR

    Energy Technology Data Exchange (ETDEWEB)

    Arganis Juárez, C.R., E-mail: carlos.arganis@inin.gob.mx; Hernández Callejas, R.; Medina Almazán, A.L.

    2015-05-15

    Highlights: • Two models were used to predict SCC growth rate in a core shroud of a BWR. • A weld residual stress distribution with 30% stress relaxation by neutron was used. • Agreement is shown between the measurements of SCC growth rate and the predictions. • Slip–oxidation model is better at low fluences and empirical model at high fluences. - Abstract: An empirical crack growth rate correlation model and a predictive model based on the slip–oxidation mechanism for Stress Corrosion Cracking (SCC) were used to calculate the crack growth rate in a BWR core shroud. In this study, the crack growth rate was calculated by accounting for the environmental factors related to aqueous environment, neutron irradiation to high fluence and the complex residual stress conditions resulting from welding. In estimating the SCC behavior the crack growth measurements data from a Boiling Water Reactor (BWR) plant are referred to, and the stress intensity factor vs crack depth throughout thickness is calculated using a generic weld residual stress distribution for a core shroud, with a 30% stress relaxation induced by neutron irradiation. Quantitative agreement is shown between the measurements of SCC growth rate and the predictions of the slip–oxidation mechanism model for relatively low fluences (5 × 10{sup 24} n/m{sup 2}), and the empirical model predicted better the SCC growth rate than the slip–oxidation model for high fluences (>1 × 10{sup 25} n/m{sup 2}). The relevance of the models predictions for SCC growth rate behavior depends on knowing the model parameters.

  8. A High-Resolution Model of Water Mass Transformation and Transport in the Weddell Sea

    Science.gov (United States)

    Hazel, J.; Stewart, A.

    2016-12-01

    The ocean circulation around the Antarctic margins has a pronounced impact on the global ocean and climate system. One of these impacts includes closing the global meridional overturning circulation (MOC) via formation of dense Antarctic Bottom Water (AABW), which ventilates a large fraction of the subsurface ocean. AABW is also partially composed of modified Circumpolar Deep Water (CDW), a warm, mid-depth water mass whose transport towards the continent has the potential to induce rapid retreat of marine-terminating glaciers. Previous studies suggest that these water mass exchanges may be strongly influenced by high-frequency processes such as downslope gravity currents, tidal flows, and mesoscale/submesoscale eddy transport. However, evaluating the relative contributions of these processes to near-Antarctic water mass transports is hindered by the region's relatively small scales of motion and the logistical difficulties in taking measurements beneath sea ice.In this study we develop a regional model of the Weddell Sea, the largest established source of AABW. The model is forced by an annually-repeating atmospheric state constructed from the Antarctic Mesoscale Prediction System data and by annually-repeating lateral boundary conditions constructed from the Southern Ocean State Estimate. The model incorporates the full Filchner-Ronne cavity and simulates the thermodynamics and dynamics of sea ice. To analyze the role of high-frequency processes in the transport and transformation of water masses, we compute the model's overturning circulation, water mass transformations, and ice sheet basal melt at model horizontal grid resolutions ranging from 1/2 degree to 1/24 degree. We temporally decompose the high-resolution (1/24 degree) model circulation into components due to mean, eddy and tidal flows and discuss the geographical dependence of these processes and their impact on water mass transformation and transport.

  9. Validation of Simplified Load Equations Through Loads Measurement and Modeling of a Small Horizontal-Axis Wind Turbine Tower

    Energy Technology Data Exchange (ETDEWEB)

    Dana, Scott [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Van Dam, Jeroen J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Damiani, Rick R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-24

    As part of an ongoing effort to improve the modeling and prediction of small wind turbine dynamics, the National Renewable Energy Laboratory (NREL) tested a small horizontal-axis wind turbine in the field at the National Wind Technology Center. The test turbine was a 2.1-kW downwind machine mounted on an 18-m multi-section fiberglass composite tower. The tower was instrumented and monitored for approximately 6 months. The collected data were analyzed to assess the turbine and tower loads and further validate the simplified loads equations from the International Electrotechnical Commission (IEC) 61400-2 design standards. Field-measured loads were also compared to the output of an aeroelastic model of the turbine. In particular, we compared fatigue loads as measured in the field, predicted by the aeroelastic model, and calculated using the simplified design equations. Ultimate loads at the tower base were assessed using both the simplified design equations and the aeroelastic model output. The simplified design equations in IEC 61400-2 do not accurately model fatigue loads and a discussion about the simplified design equations is discussed.

  10. THERMOSS: A thermohydraulic model of flow stagnation in a horizontal fuel channel

    International Nuclear Information System (INIS)

    Gulshani, P.; Caplan, M.Z.; Spinks, N.J.

    1984-01-01

    A model, called THERMOSS, is developed to compute the duration of stagnation in a CANDU reactor fuel channel with subcooled, stagnant initial conditions. The model solves, in closed form, the one dimensional, two-fluid conservation equations. In the computation of the duration of stagnation, the channel water level is an important intermediate variable because it determines the amount of steam production. A feature of the model is that water level is determined by a momentum balance between frictional pressure drop in the steam phase and hydrostatic head in the liquid phase. This is in contrast to an ealier model in which the level was determined from mass balance considerations. A satisfactory agreement between the predicted and experimentally observed channel water level and duration of stagnation is obtained. (orig.)

  11. Range-Specific High-Resolution Mesoscale Model Setup: Data Assimilation

    Science.gov (United States)

    Watson, Leela R.

    2014-01-01

    Mesoscale weather conditions can have an adverse effect on space launch, landing, and ground processing at the Eastern Range (ER) in Florida and Wallops Flight Facility (WFF) in Virginia. During summer, land-sea interactions across Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) lead to sea breeze front formation, which can spawn deep convection that can hinder operations and endanger personnel and resources. Many other weak locally driven low-level boundaries and their interactions with the sea breeze front and each other can also initiate deep convection in the KSC/CCAFS area. Some of these other boundaries include the Indian River breeze front, Banana River breeze front, outflows from previous convection, horizontal convective rolls, convergence lines from other inland bodies of water such as Lake Okeechobee, the trailing convergence line from convergence of sea breeze fronts due to the shape of Cape Canaveral, frictional convergence lines from the islands in the Bahamas, convergence lines from soil moisture differences, convergence lines from cloud shading, and others. All these subtle weak boundary interactions often make forecasting of operationally important weather very difficult at KSC/CCAFS during the convective season (May-Oct). These convective processes often build quickly, last a short time (60 minutes or less), and occur over small distances, all of which also poses a significant challenge to the local forecasters who are responsible for issuing weather advisories, watches, and warnings. Surface winds during the transition seasons of spring and fall pose the most difficulties for the forecasters at WFF. They also encounter problems forecasting convective activity and temperature during those seasons. Therefore, accurate mesoscale model forecasts are needed to aid in their decision making. Both the ER and WFF would benefit greatly from high-resolution mesoscale model output to better forecast a variety of unique weather

  12. Integrated 3D geology modeling constrained by facies and horizontal well data for Block M of the Orinoco heavy oil belt

    Energy Technology Data Exchange (ETDEWEB)

    Longxin, M.; Baojun, X.; Shancheng, Z.; Guoqing, H. [CNPC America Ltd., Caracas (Venezuela)

    2008-10-15

    Horizontal well drilling with cold production were used to develop most of heavy oil fields in Venezuela's Orinoco heavy oil belt. This study interpreted the horizontal well logs of Block M of the Orinoco heavy oil belt in an effort to improve production from this highly porous and permeable reservoir. The reservoir is comprised primarily of non-consolidated sandstones. A porosity calculation formula for the horizontal well without porosity logs was established based on the study of horizontal well logging data of block M in the Orinoco heavy oil belt. A high quality 3-D simulation tool was used to separate the block into several different sections. A set of methods were presented in order to identify if the well track was approaching an adjacent formation, to estimate the distance between the well track and the adjacent formation, and to correct the deep resistivity of the horizontal section affected by the adjacent formation. A set of interpretation techniques were established, based on the combination of well logging data, seismic data and the oilfield development performance data. It was concluded that the development of the precise 3D geological model helped to establish a solid foundation for guiding the well position design and the drilling of the horizontal well. It also contributed to the reservoir numerical simulation and the effective development of the oil field. 6 refs., 2 tabs., 14 figs.

  13. Improving Arctic Sea Ice Edge Forecasts by Assimilating High Horizontal Resolution Sea Ice Concentration Data into the US Navy’s Ice Forecast Systems

    Science.gov (United States)

    2016-06-13

    Satellite Program (DMSP) Special Sensor Mi- crowave/Imager ( SSMI and then SSMIS ). The resolution of the satellite-derived product was approximately...that only assimilated SSMIS data. A second evaluation as- similating the new blended sea ice concentration product into the pre-operational Navy...Global Ocean Forecast System 3.1 also showed a substantial improvement in ice edge location over a system using the SSMIS sea ice concentration product

  14. A model study of mixing and entrainment in the horizontally evolving atmospheric convective boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Fedorovich, E.; Kaiser, R. [Univ. Karlsruhe, Inst. fuer Hydrologie und Wasserwirtschaft (Germany)

    1997-10-01

    We present results from a parallel wind-tunnel/large-eddy simulation (LES) model study of mixing and entrainment in the atmospheric convective boundary layer (CBL) longitudinally developing over a heated surface. The advection-type entrainment of warmer air from upper turbulence-free layers into the growing CBL has been investigated. Most of numerical and laboratory model studies of the CBL carried out so far dealt with another type of entrainment, namely the non-steady one, regarding the CBL growth as a non-stationary process. In the atmosphere, both types of the CBL development can take place, often being superimposed. (au)

  15. New flow boiling heat transfer model for hydrocarbons evaporating inside horizontal tubes

    International Nuclear Information System (INIS)

    Chen, G. F.; Gong, M. Q.; Wu, J. F.; Zou, X.; Wang, S.

    2014-01-01

    Hydrocarbons have high thermodynamic performances, belong to the group of natural refrigerants, and they are the main components in mixture Joule-Thomson low temperature refrigerators (MJTR). New evaluations of nucleate boiling contribution and nucleate boiling suppression factor in flow boiling heat transfer have been proposed for hydrocarbons. A forced convection heat transfer enhancement factor correlation incorporating liquid velocity has also been proposed. In addition, the comparisons of the new model and other classic models were made to evaluate its accuracy in heat transfer prediction

  16. Performance and results of the high-resolution biogeochemical model PELAGOS025 within NEMO

    Science.gov (United States)

    Epicoco, I.; Mocavero, S.; Macchia, F.; Vichi, M.; Lovato, T.; Masina, S.; Aloisio, G.

    2015-12-01

    The present work aims at evaluating the scalability performance of a high-resolution global ocean biogeochemistry model (PELAGOS025) on massive parallel architectures and the benefits in terms of the time-to-solution reduction. PELAGOS025 is an on-line coupling between the physical ocean model NEMO and the BFM biogeochemical model. Both the models use a parallel domain decomposition along the horizontal dimension. The parallelisation is based on the message passing paradigm. The performance analysis has been done on two parallel architectures, an IBM BlueGene/Q at ALCF (Argonne Leadership Computing Facilities) and an IBM iDataPlex with Sandy Bridge processors at CMCC (Euro Mediterranean Center on Climate Change). The outcome of the analysis demonstrated that the lack of scalability is due to several factors such as the I/O operations, the memory contention, the load unbalancing due to the memory structure of the BFM component and, for the BlueGene/Q, the absence of a hybrid parallelisation approach.

  17. An Improved Rate-Transient Analysis Model of Multi-Fractured Horizontal Wells with Non-Uniform Hydraulic Fracture Properties

    Directory of Open Access Journals (Sweden)

    Youwei He

    2018-02-01

    Full Text Available Although technical advances in hydraulically fracturing and drilling enable commercial production from tight reservoirs, oil/gas recovery remains at a low level. Due to the technical and economic limitations of well-testing operations in tight reservoirs, rate-transient analysis (RTA has become a more attractive option. However, current RTA models hardly consider the effect of the non-uniform production on rate decline behaviors. In fact, PLT results demonstrate that production profile is non-uniform. To fill this gap, this paper presents an improved RTA model of multi-fractured horizontal wells (MFHWs to investigate the effects of non-uniform properties of hydraulic fractures (production of fractures, fracture half-length, number of fractures, fracture conductivity, and vertical permeability on rate transient behaviors through the diagnostic type curves. Results indicate obvious differences on the rate decline curves among the type curves of uniform properties of fractures (UPF and non-uniform properties of fractures (NPF. The use of dimensionless production integral derivative curve magnifies the differences so that we can diagnose the phenomenon of non-uniform production. Therefore, it’s significant to incorporate the effects of NPF into the RDA models of MFHWs, and the model proposed in this paper enables us to better evaluate well performance based on long-term production data.

  18. Modeling total phosphorus removal in an aquatic environment restoring horizontal subsurface flow constructed wetland based on artificial neural networks.

    Science.gov (United States)

    Li, Wei; Zhang, Yan; Cui, Lijuan; Zhang, Manyin; Wang, Yifei

    2015-08-01

    A horizontal subsurface flow constructed wetland (HSSF-CW) was designed to improve the water quality of an artificial lake in Beijing Wildlife Rescue and Rehabilitation Center, Beijing, China. Artificial neural networks (ANNs), including multilayer perceptron (MLP) and radial basis function (RBF), were used to model the removal of total phosphorus (TP). Four variables were selected as the input parameters based on the principal component analysis: the influent TP concentration, water temperature, flow rate, and porosity. In order to improve model accuracy, alternative ANNs were developed by incorporating meteorological variables, including precipitation, air humidity, evapotranspiration, solar heat flux, and barometric pressure. A genetic algorithm and cross-validation were used to find the optimal network architectures for the ANNs. Comparison of the observed data and the model predictions indicated that, with careful variable selection, ANNs appeared to be an efficient and robust tool for predicting TP removal in the HSSF-CW. Comparison of the accuracy and efficiency of MLP and RBF for predicting TP removal showed that the RBF with additional meteorological variables produced the most accurate results, indicating a high potentiality for modeling TP removal in the HSSF-CW.

  19. Effects of lateral boundary condition resolution and update frequency on regional climate model predictions

    Science.gov (United States)

    Pankatz, Klaus; Kerkweg, Astrid

    2015-04-01

    . Theoretically, regional down-scaling should act like a magnifying glass. It should reveal details on small scales which a global model cannot resolve, but it should not affect the large scale flow. As the development of the small scale features takes some time, it is important that the air stays long enough within the regional domain. The spin-up time of the small scale features is, of course, dependent on the resolution of the LBC and the resolution of the RCM. The second study examines the quality of decadal hind-casts over Europe of the decade 2001-2010 when the horizontal resolution of the driving model, namely 2.8°, 1.8°, 1.4°, 1.1°, from which the LBC are calculated, is altered. The study shows, that a smaller resolution gap between LBC resolution and RCM resolution might be beneficial.

  20. A high-resolution global flood hazard model

    Science.gov (United States)

    Sampson, Christopher C.; Smith, Andrew M.; Bates, Paul B.; Neal, Jeffrey C.; Alfieri, Lorenzo; Freer, Jim E.

    2015-09-01

    Floods are a natural hazard that affect communities worldwide, but to date the vast majority of flood hazard research and mapping has been undertaken by wealthy developed nations. As populations and economies have grown across the developing world, so too has demand from governments, businesses, and NGOs for modeled flood hazard data in these data-scarce regions. We identify six key challenges faced when developing a flood hazard model that can be applied globally and present a framework methodology that leverages recent cross-disciplinary advances to tackle each challenge. The model produces return period flood hazard maps at ˜90 m resolution for the whole terrestrial land surface between 56°S and 60°N, and results are validated against high-resolution government flood hazard data sets from the UK and Canada. The global model is shown to capture between two thirds and three quarters of the area determined to be at risk in the benchmark data without generating excessive false positive predictions. When aggregated to ˜1 km, mean absolute error in flooded fraction falls to ˜5%. The full complexity global model contains an automatically parameterized subgrid channel network, and comparison to both a simplified 2-D only variant and an independently developed pan-European model shows the explicit inclusion of channels to be a critical contributor to improved model performance. While careful processing of existing global terrain data sets enables reasonable model performance in urban areas, adoption of forthcoming next-generation global terrain data sets will offer the best prospect for a step-change improvement in model performance.

  1. Nested high resolution models for the coastal areas of the North Indian Ocean

    Science.gov (United States)

    Wobus, Fred; Shapiro, Georgy

    2017-04-01

    Oceanographic processes at coastal scales require much higher horizontal resolution from both ocean models and observations as compared to deep water oceanography. Aside from a few exceptions such as land-locked seas, the hydrodynamics of coastal shallow waters is strongly influenced by the tides, which in turn control the mixing, formation of temperature fronts and other phenomena. The numerical modelling of the coastal domains requires good knowledge of the lateral boundary conditions. The application of lateral boundary conditions to ocean models is a notoriously tricky task, but can only be avoided with global ocean models. Smaller scale regional ocean models are typically nested within global models, and even smaller-scale coastal models may be nested within regional models, creating a nesting chain. However a direct nesting of a very high resolution coastal model into a coarse resolution global model results in degrading of the accuracy of the outputs due to the large difference between the model resolutions. This is why a nesting chain has to be applied, so that every increase in resolution is kept within a reasonable minimum (typically by a factor of 3 to 5 at each step). Global models are traditionally non-tidal, so at some stage of the nesting chain the tides need to be introduced. This is typically done by calculating the tidal constituents from a dedicated tidal model (e.g. TPXO) for all boundary points of a nested model. The tidal elevation at each boundary location can then be calculated from the harmonics at every model time step and the added to the parent model non-tidal SSH. This combination of harmonics-derived tidal SSH and non-tidal parent model SSH is typically applied to the nested domain using the Flather condition, together with the baroclinic velocities from the parent model. The harmonics-derived SSH cannot be added to an SSH signal that is already tidal, so the parent model SSH has to be either detided or taken from a non-tidal model

  2. High-Resolution Mesoscale Model Setup for the Eastern Range and Wallops Flight Facility

    Science.gov (United States)

    Watson, Leela R.; Zavodsky, Bradley T.

    2015-01-01

    Mesoscale weather conditions can have an adverse effect on space launch, landing, ground processing, and weather advisories, watches, and warnings at the Eastern Range (ER) in Florida and Wallops Flight Facility (WFF) in Virginia. During summer, land-sea interactions across Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) lead to sea breeze front formation, which can spawn deep convection that can hinder operations and endanger personnel and resources. Many other weak locally-driven low-level boundaries and their interactions with the sea breeze front and each other can also initiate deep convection in the KSC/CCAFS area. These convective processes often last 60 minutes or less and pose a significant challenge to the local forecasters. Surface winds during the transition seasons (spring and fall) pose the most difficulties for the forecasters at WFF. They also encounter problems forecasting convective activity and temperature during those seasons. Therefore, accurate mesoscale model forecasts are needed to better forecast a variety of unique weather phenomena. Global and national scale models cannot properly resolve important local-scale weather features at each location due to their horizontal resolutions being much too coarse. Therefore, a properly tuned local data assimilation (DA) and forecast model at a high resolution is needed to provide improved capability. To accomplish this, a number of sensitivity tests were performed using the Weather Research and Forecasting (WRF) model in order to determine the best DA/model configuration for operational use at each of the space launch ranges to best predict winds, precipitation, and temperature. A set of Perl scripts to run the Gridpoint Statistical Interpolation (GSI)/WRF in real-time were provided by NASA's Short-term Prediction Research and Transition Center (SPoRT). The GSI can analyze many types of observational data including satellite, radar, and conventional data. The GSI/WRF scripts

  3. Crust and Mantle Deformation Revealed from High-Resolution Radially Anisotropic Velocity Models

    Science.gov (United States)

    Li, A.; Dave, R.; Yao, Y.

    2017-12-01

    Love wave tomography, which can achieve a similar model resolution as Rayleigh wave, so far has limited applications to the USArray data. Recently, we have developed high-resolution Love wave phase velocity maps in the Wyoming craton and Texas using data at the Transportable Array stations. 3-D, radially anisotropic velocity models are obtained by jointly inverting Love and Rayleigh wave phase velocities. A high-velocity anomaly extending to about 200 km depth beneath central Wyoming correlates with negative radial anisotropy (Vsv>Vsh), suggesting that mantle downwelling develops under the cratonic lithosphere. Surprisingly, the significantly low velocity beneath the Yellowstone hotspot, which has been interpreted as partial melting and asthenospheric upwelling, is associated with the largest radial anisotropy (Vsh>Vsv) in the area. This observation does not support mantle upwelling. Instead, it indicates that the upper mantle beneath the hotspot has experienced strong shear deformation probably by the plate motion and large-scale mantle flow. In Texas, positive radial anisotropy in the lower crust extends from the coast to the Ouachita belt, which is characterized by high velocity and negative radial anisotropy. In the upper mantle, large variations of velocity and anisotropy exit under the coastal plain. A common feature in these anisotropic models is that high-velocity anomalies in the upper mantle often correlate with negative anisotropy (Vsv>Vsh) while low-velocity anomalies are associated with positive anisotropy (Vsh>Vsv). The manifestation of mantle downweling as negative radial anisotropy is largely due to the relatively high viscosity of the high-velocity mantle block, which is less affected by the surrounding large-scale horizontal flow. However, mantle upwelling, which is often associated with low-velocity anomalies, presumably low-viscosity mantle blocks, is invisible in radial anisotropy models. Such upwelling may happen too quickly to make last

  4. CFD Modeling of Gas-Liquid Bubbly Flow in Horizontal Pipes: Influence of Bubble Coalescence and Breakup

    Directory of Open Access Journals (Sweden)

    K. Ekambara

    2012-01-01

    Full Text Available Modelling of gas-liquid bubbly flows is achieved by coupling a population balance equation with the three-dimensional, two-fluid, hydrodynamic model. For gas-liquid bubbly flows, an average bubble number density transport equation has been incorporated in the CFD code CFX 5.7 to describe the temporal and spatial evolution of the gas bubbles population. The coalescence and breakage effects of the gas bubbles are modeled. The coalescence by the random collision driven by turbulence and wake entrainment is considered, while for bubble breakage, the impact of turbulent eddies is considered. Local spatial variations of the gas volume fraction, interfacial area concentration, Sauter mean bubble diameter, and liquid velocity are compared against experimental data in a horizontal pipe, covering a range of gas (0.25 to 1.34 m/s and liquid (3.74 to 5.1 m/s superficial velocities and average volume fractions (4% to 21%. The predicted local variations are in good agreement with the experimental measurements reported in the literature. Furthermore, the development of the flow pattern was examined at three different axial locations of L/D = 25, 148, and 253. The first location is close to the entrance region where the flow is still developing, while the second and the third represent nearly fully developed bubbly flow patterns.

  5. Fuzzy logic-based analogue forecasting and hybrid modelling of horizontal visibility

    Science.gov (United States)

    Tuba, Zoltán; Bottyán, Zsolt

    2018-04-01

    Forecasting visibility is one of the greatest challenges in aviation meteorology. At the same time, high accuracy visibility forecasts can significantly reduce or make avoidable weather-related risk in aviation as well. To improve forecasting visibility, this research links fuzzy logic-based analogue forecasting and post-processed numerical weather prediction model outputs in hybrid forecast. Performance of analogue forecasting model was improved by the application of Analytic Hierarchy Process. Then, linear combination of the mentioned outputs was applied to create ultra-short term hybrid visibility prediction which gradually shifts the focus from statistical to numerical products taking their advantages during the forecast period. It gives the opportunity to bring closer the numerical visibility forecast to the observations even it is wrong initially. Complete verification of categorical forecasts was carried out; results are available for persistence and terminal aerodrome forecasts (TAF) as well in order to compare. The average value of Heidke Skill Score (HSS) of examined airports of analogue and hybrid forecasts shows very similar results even at the end of forecast period where the rate of analogue prediction in the final hybrid output is 0.1-0.2 only. However, in case of poor visibility (1000-2500 m), hybrid (0.65) and analogue forecasts (0.64) have similar average of HSS in the first 6 h of forecast period, and have better performance than persistence (0.60) or TAF (0.56). Important achievement that hybrid model takes into consideration physics and dynamics of the atmosphere due to the increasing part of the numerical weather prediction. In spite of this, its performance is similar to the most effective visibility forecasting methods and does not follow the poor verification results of clearly numerical outputs.

  6. Three-dimensional modelling of horizontal chemical vapor deposition. I - MOCVD at atmospheric pressure

    Science.gov (United States)

    Ouazzani, Jalil; Rosenberger, Franz

    1990-01-01

    A systematic numerical study of the MOCVD of GaAs from trimethylgallium and arsine in hydrogen or nitrogen carrier gas at atmospheric pressure is reported. Three-dimensional effects are explored for CVD reactors with large and small cross-sectional aspect ratios, and the effects on growth rate uniformity of tilting the susceptor are investigated for various input flow rates. It is found that, for light carrier gases, thermal diffusion must be included in the model. Buoyancy-driven three-dimensional flow effects can greatly influence the growth rate distribution through the reactor. The importance of the proper design of the lateral thermal boundary conditions for obtaining layers of uniform thickness is emphasized.

  7. Stable, accurate and efficient computation of normal modes for horizontal stratified models

    Science.gov (United States)

    Wu, Bo; Chen, Xiaofei

    2016-08-01

    We propose an adaptive root-determining strategy that is very useful when dealing with trapped modes or Stoneley modes whose energies become very insignificant on the free surface in the presence of low-velocity layers or fluid layers in the model. Loss of modes in these cases or inaccuracy in the calculation of these modes may then be easily avoided. Built upon the generalized reflection/transmission coefficients, the concept of `family of secular functions' that we herein call `adaptive mode observers' is thus naturally introduced to implement this strategy, the underlying idea of which has been distinctly noted for the first time and may be generalized to other applications such as free oscillations or applied to other methods in use when these cases are encountered. Additionally, we have made further improvements upon the generalized reflection/transmission coefficient method; mode observers associated with only the free surface and low-velocity layers (and the fluid/solid interface if the model contains fluid layers) are adequate to guarantee no loss and high precision at the same time of any physically existent modes without excessive calculations. Finally, the conventional definition of the fundamental mode is reconsidered, which is entailed in the cases under study. Some computational aspects are remarked on. With the additional help afforded by our superior root-searching scheme and the possibility of speeding calculation using a less number of layers aided by the concept of `turning point', our algorithm is remarkably efficient as well as stable and accurate and can be used as a powerful tool for widely related applications.

  8. Neuromorphic model of magnocellular and parvocellular visual paths: spatial resolution

    International Nuclear Information System (INIS)

    Aguirre, Rolando C; Felice, Carmelo J; Colombo, Elisa M

    2007-01-01

    Physiological studies of the human retina show the existence of at least two visual information processing channels, the magnocellular and the parvocellular ones. Both have different spatial, temporal and chromatic features. This paper focuses on the different spatial resolution of these two channels. We propose a neuromorphic model, so that they match the retina's physiology. Considering the Deutsch and Deutsch model (1992), we propose two configurations (one for each visual channel) of the connection between the retina's different cell layers. The responses of the proposed model have similar behaviour to those of the visual cells: each channel has an optimum response corresponding to a given stimulus size which decreases for larger or smaller stimuli. This size is bigger for the magno path than for the parvo path and, in the end, both channels produce a magnifying of the borders of a stimulus

  9. Modeling noncontact atomic force microscopy resolution on corrugated surfaces

    Directory of Open Access Journals (Sweden)

    Kristen M. Burson

    2012-03-01

    Full Text Available Key developments in NC-AFM have generally involved atomically flat crystalline surfaces. However, many surfaces of technological interest are not atomically flat. We discuss the experimental difficulties in obtaining high-resolution images of rough surfaces, with amorphous SiO2 as a specific case. We develop a quasi-1-D minimal model for noncontact atomic force microscopy, based on van der Waals interactions between a spherical tip and the surface, explicitly accounting for the corrugated substrate (modeled as a sinusoid. The model results show an attenuation of the topographic contours by ~30% for tip distances within 5 Å of the surface. Results also indicate a deviation from the Hamaker force law for a sphere interacting with a flat surface.

  10. CFD modelling of liquid-solid transport in the horizontal eccentric annuli

    Science.gov (United States)

    Sayindla, Sneha; Challabotla, Niranjan Reddy

    2017-11-01

    In oil and gas drilling operations, different types of drilling fluids are used to transport the solid cuttings in an annulus between drill pipe and well casing. The inner pipe is often eccentric and flow inside the annulus can be laminar or turbulent regime. In the present work, Eulerian-Eulerian granular multiphase CFD model is developed to systematically investigate the effect of the rheology of the drilling fluid type (Newtonian and non-Newtonian), drill pipe eccentricity and inner pipe rotation on the efficiency of cuttings transport. Both laminar and turbulent flow regimes were considered. Frictional pressure drop is computed and compared with the flow loop experimental results reported in the literature. The results confirm that the annular frictional pressure loss in a fully eccentric annulus are significantly lesser than the concentric annulus. Inner pipe rotation improve the efficiency of the cuttings transport in laminar flow regime. Cuttings transport velocity and concentration distribution were analysed to predict the different flow patterns such as stationary bed, moving bed, heterogeneous and homogeneous bed formation.

  11. A Comprehensive Prediction Model of Hydraulic Extended-Reach Limit Considering the Allowable Range of Drilling Fluid Flow Rate in Horizontal Drilling.

    Science.gov (United States)

    Li, Xin; Gao, Deli; Chen, Xuyue

    2017-06-08

    Hydraulic extended-reach limit (HERL) model of horizontal extended-reach well (ERW) can predict the maximum measured depth (MMD) of the horizontal ERW. The HERL refers to the well's MMD when drilling fluid cannot be normally circulated by drilling pump. Previous model analyzed the following two constraint conditions, drilling pump rated pressure and rated power. However, effects of the allowable range of drilling fluid flow rate (Q min  ≤ Q ≤ Q max ) were not considered. In this study, three cases of HERL model are proposed according to the relationship between allowable range of drilling fluid flow rate and rated flow rate of drilling pump (Q r ). A horizontal ERW is analyzed to predict its HERL, especially its horizontal-section limit (L h ). Results show that when Q min  ≤ Q r  ≤ Q max (Case I), L h depends both on horizontal-section limit based on rated pump pressure (L h1 ) and horizontal-section limit based on rated pump power (L h2 ); when Q min  < Q max  < Q r (Case II), L h is exclusively controlled by L h1 ; while L h is only determined by L h2 when Q r  < Q min  < Q max (Case III). Furthermore, L h1 first increases and then decreases with the increase in drilling fluid flow rate, while L h2 keeps decreasing as the drilling fluid flow rate increases. The comprehensive model provides a more accurate prediction on HERL.

  12. Watershed sensitivity and hydrologic response to high-resolution climate model

    Science.gov (United States)

    Troin, M.; Caya, D.

    2012-12-01

    Global climate models (GCMs) are fundamental research tools to assess climate change impacts on water resources. Regional climate models (RCMs) are complementary to GCMs. The added benefit of RCMs for hydrological applications is still not well understood because watersheds respond differently to RCM experiments. It is expected that the new generation of RCMs improve the representation of climate processes making it more attractive for impact studies. Given the cost of RCMs, it is ascertain to identify whether high-resolution RCMs allow offering more details than what is simulated in GCMs or RCMs with coarser resolution to address impacts on water resources. This study aims to assess the added value of RCM with emphasis on using high-resolution climate models. More specifically is how the hydrological cycle is represented when the resolution in climate models is increased (45 vs 200km; 15 vs 45km). We used simulations from the Canadian RCM (CRCM) driven by reanalyses integrated on high-resolution domains (45 and 15km) and CRCM driven by multiple members of two GCMs (the Canadian CGCM3; the German ECHAM5) with a horizontal resolution of 45 km. CRCM data and data from their host GCMs are compared to observation over 1971-2000. Precipitation and temperature from CRCM and GCMs' simulations are inputted into the hydrological SWAT model to simulate streamflow in watersheds for the historical period. The selected watersheds are two basins in Quebec (QC) and one basin in British Columbia (BC), Canada. CRCM-45km driven by GCMs performs well in representing precipitation but shows a cold bias of 3.3°C. Such bias in temperature is more significant for the BC basin (4.5°C) due to the Rocky Mountains. For the CRCM-45km/GCM combination (CGCM3 or ECHAM5), comparable skills in reproducing the observed climate are identified even though CGCM3 analyzed alone provides more accurate indication of climatology in the basins than ECHAM5. When we compared to GCMs results, CRCM-45km

  13. A semi-empirical model for the estimation of maximum horizontal displacement due to liquefaction-induced lateral spreading

    Science.gov (United States)

    Faris, Allison T.; Seed, Raymond B.; Kayen, Robert E.; Wu, Jiaer

    2006-01-01

    During the 1906 San Francisco Earthquake, liquefaction-induced lateral spreading and resultant ground displacements damaged bridges, buried utilities, and lifelines, conventional structures, and other developed works. This paper presents an improved engineering tool for the prediction of maximum displacement due to liquefaction-induced lateral spreading. A semi-empirical approach is employed, combining mechanistic understanding and data from laboratory testing with data and lessons from full-scale earthquake field case histories. The principle of strain potential index, based primary on correlation of cyclic simple shear laboratory testing results with in-situ Standard Penetration Test (SPT) results, is used as an index to characterized the deformation potential of soils after they liquefy. A Bayesian probabilistic approach is adopted for development of the final predictive model, in order to take fullest advantage of the data available and to deal with the inherent uncertainties intrinstiic to the back-analyses of field case histories. A case history from the 1906 San Francisco Earthquake is utilized to demonstrate the ability of the resultant semi-empirical model to estimate maximum horizontal displacement due to liquefaction-induced lateral spreading.

  14. The near wake structure and the development of vorticity behind a model horizontal axis wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, P.; Wood, D. [The Univ. of Newcastle, Dept. of Mechanical Engineering, Callaghan (Australia)

    1997-08-01

    The wake of a two bladed model HAWT operating at zero yaw angle and in a steady flow in a wind tunnel was measured using hot wire probes. By phase locked averaging and moving the probe axially and radially the full three dimensional mean flow file was determined. All measurements were within two chord lengths of the blades and at tip speed ratios giving high turbine power output, a condition approaching runaway, and a stalled condition. For all tip speed ratios the wakes were significantly three dimensional. Large velocity variations were associated with vortex structures in the wakes, and irrotational fluctuations caused by the blade bound circulation. The vorticity clearly defined the hub and tip vortices that traced helical paths downstream, with the constant tip vortex pitch inversely proportional to tip speed ratio. Close to the blades the flow was complicated, though vortex roll-up was completed within one chord length. Considerable changes in wake structure occurred with tip speed ratio. At high power output the wake showed tip and hub vortices connected by a diffuse vortex sheet of mostly radial vorticity from the blade boundary layers; blade bound circulation was almost constant. The structure approaching runaway was similar though the hub vortex was not well defined and formed a vortex sheet around the hub which lifted away and diffused. The stalled condition was more complicated, with evidence of incomplete tip and hub vortex formation. The stream-wise velocity of the tip vortex core decreased with increasing tip speed ratio, but this was never aligned with local streamlines. The core of the tip vortex was not circular but more elliptical. A phase locked averaged angular momentum analysis was undertaken, the extra terms introduced through phase locked averaging were small. (Abstract Truncated)

  15. Modeling Extreme Precipitation over East China with a Global Variable-Resolution Modeling Framework (MPAS)

    Science.gov (United States)

    Zhao, C.; Xu, M.; Wang, Y.; Guo, J.; Hu, Z.; Ruby, L.; Duda, M.; Skamarock, W. C.

    2017-12-01

    Modeling extreme precipitation requires high-resolution scales. Traditional regional downscaling modeling framework has some issues such as ill-posed boundary conditions, mismatches between the driving global and regional dynamics and physics, and the lack of regional feedback to global scales. The non-hydrostatic Model for Prediction Across Scales (MPAS), a global variable-resolution modeling framework, offers an opportunity to obtain regional features at high-resolution scales using regional mesh refinement without boundary limiting. In this study, the MPAS model is first time applied with the refined meshes over East China at various high-resolutions (16 km and 4 km) to simulate an extreme precipitation event during 26-27 June 2012. The simulations are evaluated with the ground observations from the Chinese Meteorological Administration (CMA) network and the reanalysis data. Sensitivity experiments with different physics and forecast lead time are conducted to understand the uncertainties in simulating spatial and temporal variation of precipitation. The variable-resolution simulations are also compared with the traditional global uniform-resolution simulations at a relatively low scale ( 30 km) and a relatively high scale ( 16 km). The analysis shows that the variable-resolution simulation can capture the high-scale feature of precipitation over East China as the uniform-resolution simulation at a relatively high scale. It also indicates that high-resolution significantly improves the capability of simulating extreme precipitation. The MPAS simulations are also compared with the traditional limited-area simulations at similar scales using the Weather Research and Forecasting Model (WRF). The difference between the simulations using these two different modeling framework is also discussed.

  16. Effects of Model Resolution and Ocean Mixing on Forced Ice-Ocean Physical and Biogeochemical Simulations Using Global and Regional System Models

    Science.gov (United States)

    Jin, Meibing; Deal, Clara; Maslowski, Wieslaw; Matrai, Patricia; Roberts, Andrew; Osinski, Robert; Lee, Younjoo J.; Frants, Marina; Elliott, Scott; Jeffery, Nicole; Hunke, Elizabeth; Wang, Shanlin

    2018-01-01

    The current coarse-resolution global Community Earth System Model (CESM) can reproduce major and large-scale patterns but is still missing some key biogeochemical features in the Arctic Ocean, e.g., low surface nutrients in the Canada Basin. We incorporated the CESM Version 1 ocean biogeochemical code into the Regional Arctic System Model (RASM) and coupled it with a sea-ice algal module to investigate model limitations. Four ice-ocean hindcast cases are compared with various observations: two in a global 1° (40˜60 km in the Arctic) grid: G1deg and G1deg-OLD with/without new sea-ice processes incorporated; two on RASM's 1/12° (˜9 km) grid R9km and R9km-NB with/without a subgrid scale brine rejection parameterization which improves ocean vertical mixing under sea ice. Higher-resolution and new sea-ice processes contributed to lower model errors in sea-ice extent, ice thickness, and ice algae. In the Bering Sea shelf, only higher resolution contributed to lower model errors in salinity, nitrate (NO3), and chlorophyll-a (Chl-a). In the Arctic Basin, model errors in mixed layer depth (MLD) were reduced 36% by brine rejection parameterization, 20% by new sea-ice processes, and 6% by higher resolution. The NO3 concentration biases were caused by both MLD bias and coarse resolution, because of excessive horizontal mixing of high NO3 from the Chukchi Sea into the Canada Basin in coarse resolution models. R9km showed improvements over G1deg on NO3, but not on Chl-a, likely due to light limitation under snow and ice cover in the Arctic Basin.

  17. eWaterCycle: A high resolution global hydrological model

    Science.gov (United States)

    van de Giesen, Nick; Bierkens, Marc; Drost, Niels; Hut, Rolf; Sutanudjaja, Edwin

    2014-05-01

    In 2013, the eWaterCycle project was started, which has the ambitious goal to run a high resolution global hydrological model. Starting point was the PCR-GLOBWB built by Utrecht University. The software behind this model will partially be re-engineered in order to enable to run it in a High Performance Computing (HPC) environment. The aim is to have a spatial resolution of 1km x 1km. The idea is also to run the model in real-time and forecasting mode, using data assimilation. An on-demand hydraulic model will be available for detailed flow and flood forecasting in support of navigation and disaster management. The project faces a set of scientific challenges. First, to enable the model to run in a HPC environment, model runs were analyzed to examine on which parts of the program most CPU time was spent. These parts were re-coded in Open MPI to allow for parallel processing. Different parallelization strategies are thinkable. In our case, it was decided to use watershed logic as a first step to distribute the analysis. There is rather limited recent experience with HPC in hydrology and there is much to be learned and adjusted, both on the hydrological modeling side and the computer science side. For example, an interesting early observation was that hydrological models are, due to their localized parameterization, much more memory intensive than models of sister-disciplines such as meteorology and oceanography. Because it would be deadly to have to swap information between CPU and hard drive, memory management becomes crucial. A standard Ensemble Kalman Filter (enKF) would, for example, have excessive memory demands. To circumvent these problems, an alternative to the enKF was developed that produces equivalent results. This presentation shows the most recent results from the model, including a 5km x 5km simulation and a proof of concept for the new data assimilation approach. Finally, some early ideas about financial sustainability of an operational global

  18. Assessing Australian Rainfall Projections in Two Model Resolutions

    Science.gov (United States)

    Taschetto, A.; Haarsma, R. D.; Sen Gupta, A.

    2016-02-01

    Australian climate is projected to change with increases in greenhouse gases. The IPCC reports an increase in extreme daily rainfall across the country. At the same time, mean rainfall over southeast Australia is projected to reduce during austral winter, but to increase during austral summer, mainly associated with changes in the surrounding oceans. Climate models agree better on the future reduction of average rainfall over the southern regions of Australia compared to the increase in extreme rainfall events. One of the reasons for this disagreement may be related to climate model limitations in simulating the observed mechanisms associated with the mid-latitude weather systems, in particular due to coarse model resolutions. In this study we investigate how changes in sea surface temperature (SST) affect Australian mean and extreme rainfall under global warming, using a suite of numerical experiments at two model resolutions: about 126km (T159) and 25km (T799). The numerical experiments are performed with the earth system model EC-EARTH. Two 6-member ensembles are produced for the present day conditions and a future scenario. The present day ensemble is forced with the observed daily SST from the NOAA National Climatic Data Center from 2002 to 2006. The future scenario simulation is integrated from 2094 to 2098 using the present day SST field added onto the future SST change created from a 17-member ensemble based on the RCP4.5 scenario. Preliminary results show an increase in extreme rainfall events over Tasmania associated with enhanced convection driven by the Tasman Sea warming. We will further discuss how the projected changes in SST will impact the southern mid-latitude weather systems that ultimately affect Australian rainfall.

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

    Science.gov (United States)

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

    2016-08-01

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

  20. High resolution modelling of extreme precipitation events in urban areas

    Science.gov (United States)

    Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

    2015-04-01

    The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with

  1. Effect of model resolution on a regional climate model simulation over southeast Australia

    KAUST Repository

    Evans, J. P.

    2013-03-26

    Dynamically downscaling climate projections from global climate models (GCMs) for use in impacts and adaptation research has become a common practice in recent years. In this study, the CSIRO Mk3.5 GCM is downscaled using the Weather Research and Forecasting (WRF) regional climate model (RCM) to medium (50 km) and high (10 km) resolution over southeast Australia. The influence of model resolution on the present-day (1985 to 2009) modelled regional climate and projected future (2075 to 2099) changes are examined for both mean climate and extreme precipitation characteristics. Increasing model resolution tended to improve the simulation of present day climate, with larger improvements in areas affected by mountains and coastlines. Examination of circumstances under which increasing the resolution decreased performance revealed an error in the GCM circulation, the effects of which had been masked by the coarse GCM topography. Resolution modifications to projected changes were largest in regions with strong topographic and coastline influences, and can be large enough to change the sign of the climate change projected by the GCM. Known physical mechanisms for these changes included orographic uplift and low-level blocking of air-masses caused by mountains. In terms of precipitation extremes, the GCM projects increases in extremes even when the projected change in the mean was a decrease: but this was not always true for the higher resolution models. Thus, while the higher resolution RCM climate projections often concur with the GCM projections, there are times and places where they differ significantly due to their better representation of physical processes. It should also be noted that the model resolution can modify precipitation characteristics beyond just its mean value.

  2. Evaluation of the Actuator Line Model with coarse resolutions

    Science.gov (United States)

    Draper, M.; Usera, G.

    2015-06-01

    The aim of the present paper is to evaluate the Actuator Line Model (ALM) in spatial resolutions coarser than what is generally recommended, also using larger time steps. To accomplish this, the ALM has been implemented in the open source code caffa3d.MBRi and validated against experimental measurements of two wind tunnel campaigns (stand alone wind turbine and two wind turbines in line, case A and B respectively), taking into account two spatial resolutions: R/8 and R/15 (R is the rotor radius). A sensitivity analysis in case A was performed in order to get some insight into the influence of the smearing factor (3D Gaussian distribution) and time step size in power and thrust, as well as in the wake, without applying a tip loss correction factor (TLCF), for one tip speed ratio (TSR). It is concluded that as the smearing factor is larger or time step size is smaller the power is increased, but the velocity deficit is not as much affected. From this analysis, a smearing factor was obtained in order to calculate precisely the power coefficient for that TSR without applying TLCF. Results with this approach were compared with another simulation choosing a larger smearing factor and applying Prandtl's TLCF, for three values of TSR. It is found that applying the TLCF improves the power estimation and weakens the influence of the smearing factor. Finally, these 2 alternatives were tested in case B, confirming that conclusion.

  3. Large-watershed flood simulation and forecasting based on different-resolution distributed hydrological model

    Science.gov (United States)

    Li, J.

    2017-12-01

    Large-watershed flood simulation and forecasting is very important for a distributed hydrological model in the application. There are some challenges including the model's spatial resolution effect, model performance and accuracy and so on. To cope with the challenge of the model's spatial resolution effect, different model resolution including 1000m*1000m, 600m*600m, 500m*500m, 400m*400m, 200m*200m were used to build the distributed hydrological model—Liuxihe model respectively. The purpose is to find which one is the best resolution for Liuxihe model in Large-watershed flood simulation and forecasting. This study sets up a physically based distributed hydrological model for flood forecasting of the Liujiang River basin in south China. Terrain data digital elevation model (DEM), soil type and land use type are downloaded from the website freely. The model parameters are optimized by using an improved Particle Swarm Optimization(PSO) algorithm; And parameter optimization could reduce the parameter uncertainty that exists for physically deriving model parameters. The different model resolution (200m*200m—1000m*1000m ) are proposed for modeling the Liujiang River basin flood with the Liuxihe model in this study. The best model's spatial resolution effect for flood simulation and forecasting is 200m*200m.And with the model's spatial resolution reduction, the model performance and accuracy also become worse and worse. When the model resolution is 1000m*1000m, the flood simulation and forecasting result is the worst, also the river channel divided based on this resolution is differs from the actual one. To keep the model with an acceptable performance, minimum model spatial resolution is needed. The suggested threshold model spatial resolution for modeling the Liujiang River basin flood is a 500m*500m grid cell, but the model spatial resolution with a 200m*200m grid cell is recommended in this study to keep the model at a best performance.

  4. Revised Phylogeny and Novel Horizontally Acquired Virulence Determinants of the Model Soft Rot Phytopathogen Pectobacterium wasabiae SCC3193

    Science.gov (United States)

    Koskinen, Patrik; Nokso-Koivisto, Jussi; Pasanen, Miia; Broberg, Martin; Plyusnin, Ilja; Törönen, Petri; Holm, Liisa; Pirhonen, Minna; Palva, E. Tapio

    2012-01-01

    Soft rot disease is economically one of the most devastating bacterial diseases affecting plants worldwide. In this study, we present novel insights into the phylogeny and virulence of the soft rot model Pectobacterium sp. SCC3193, which was isolated from a diseased potato stem in Finland in the early 1980s. Genomic approaches, including proteome and genome comparisons of all sequenced soft rot bacteria, revealed that SCC3193, previously included in the species Pectobacterium carotovorum, can now be more accurately classified as Pectobacterium wasabiae. Together with the recently revised phylogeny of a few P. carotovorum strains and an increasing number of studies on P. wasabiae, our work indicates that P. wasabiae has been unnoticed but present in potato fields worldwide. A combination of genomic approaches and in planta experiments identified features that separate SCC3193 and other P. wasabiae strains from the rest of soft rot bacteria, such as the absence of a type III secretion system that contributes to virulence of other soft rot species. Experimentally established virulence determinants include the putative transcriptional regulator SirB, two partially redundant type VI secretion systems and two horizontally acquired clusters (Vic1 and Vic2), which contain predicted virulence genes. Genome comparison also revealed other interesting traits that may be related to life in planta or other specific environmental conditions. These traits include a predicted benzoic acid/salicylic acid carboxyl methyltransferase of eukaryotic origin. The novelties found in this work indicate that soft rot bacteria have a reservoir of unknown traits that may be utilized in the poorly understood latent stage in planta. The genomic approaches and the comparison of the model strain SCC3193 to other sequenced Pectobacterium strains, including the type strain of P. wasabiae, provides a solid basis for further investigation of the virulence, distribution and phylogeny of soft rot

  5. Revised phylogeny and novel horizontally acquired virulence determinants of the model soft rot phytopathogen Pectobacterium wasabiae SCC3193.

    Directory of Open Access Journals (Sweden)

    Johanna Nykyri

    Full Text Available Soft rot disease is economically one of the most devastating bacterial diseases affecting plants worldwide. In this study, we present novel insights into the phylogeny and virulence of the soft rot model Pectobacterium sp. SCC3193, which was isolated from a diseased potato stem in Finland in the early 1980s. Genomic approaches, including proteome and genome comparisons of all sequenced soft rot bacteria, revealed that SCC3193, previously included in the species Pectobacterium carotovorum, can now be more accurately classified as Pectobacterium wasabiae. Together with the recently revised phylogeny of a few P. carotovorum strains and an increasing number of studies on P. wasabiae, our work indicates that P. wasabiae has been unnoticed but present in potato fields worldwide. A combination of genomic approaches and in planta experiments identified features that separate SCC3193 and other P. wasabiae strains from the rest of soft rot bacteria, such as the absence of a type III secretion system that contributes to virulence of other soft rot species. Experimentally established virulence determinants include the putative transcriptional regulator SirB, two partially redundant type VI secretion systems and two horizontally acquired clusters (Vic1 and Vic2, which contain predicted virulence genes. Genome comparison also revealed other interesting traits that may be related to life in planta or other specific environmental conditions. These traits include a predicted benzoic acid/salicylic acid carboxyl methyltransferase of eukaryotic origin. The novelties found in this work indicate that soft rot bacteria have a reservoir of unknown traits that may be utilized in the poorly understood latent stage in planta. The genomic approaches and the comparison of the model strain SCC3193 to other sequenced Pectobacterium strains, including the type strain of P. wasabiae, provides a solid basis for further investigation of the virulence, distribution and phylogeny

  6. High-resolution Doppler model of the human gait

    Science.gov (United States)

    Geisheimer, Jonathan L.; Greneker, Eugene F., III; Marshall, William S.

    2002-07-01

    A high resolution Doppler model of the walking human was developed for analyzing the continuous wave (CW) radar gait signature. Data for twenty subjects were collected simultaneously using an infrared motion capture system along with a two channel 10.525 GHz CW radar. The motion capture system recorded three-dimensional coordinates of infrared markers placed on the body. These body marker coordinates were used as inputs to create the theoretical Doppler output using a model constructed in MATLAB. The outputs of the model are the simulated Doppler signals due to each of the major limbs and the thorax. An estimated radar cross section for each part of the body was assigned using the Lund & Browder chart of estimated body surface area. The resultant Doppler model was then compared with the actual recorded Doppler gait signature in the frequency domain using the spectrogram. Comparison of the two sets of data has revealed several identifiable biomechanical features in the radar gait signature due to leg and body motion. The result of the research shows that a wealth of information can be unlocked from the radar gait signature, which may be useful in security and biometric applications.

  7. Low Resolution Refinement of Atomic Models Against Crystallographic Data.

    Science.gov (United States)

    Nicholls, Robert A; Kovalevskiy, Oleg; Murshudov, Garib N

    2017-01-01

    This review describes some of the problems encountered during low-resolution refinement and map calculation. Refinement is considered as an application of Bayes' theorem, allowing combination of information from various sources including crystallographic experimental data and prior chemical and structural knowledge. The sources of prior knowledge relevant to macromolecules include basic chemical information such as bonds and angles, structural information from reference models of known homologs, knowledge about secondary structures, hydrogen bonding patterns, and similarity of non-crystallographically related copies of a molecule. Additionally, prior information encapsulating local conformational conservation is exploited, keeping local interatomic distances similar to those in the starting atomic model. The importance of designing an accurate likelihood function-the only link between model parameters and observed data-is emphasized. The review also reemphasizes the importance of phases, and describes how the use of raw observed amplitudes could give a better correlation between the calculated and "true" maps. It is shown that very noisy or absent observations can be replaced by calculated structure factors, weighted according to the accuracy of the atomic model. This approach helps to smoothen the map. However, such replacement should be used sparingly, as the bias toward errors in the model could be too much to avoid. It is in general recommended that, whenever a new map is calculated, map quality should be judged by inspection of the parts of the map where there is no atomic model. It is also noted that it is advisable to work with multiple blurred and sharpened maps, as different parts of a crystal may exhibit different degrees of mobility. Doing so can allow accurate building of atomic models, accounting for overall shape as well as finer structural details. Some of the results described in this review have been implemented in the programs REFMAC5, Pro

  8. HIGH-RESOLUTION ATMOSPHERIC ENSEMBLE MODELING AT SRNL

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R.; Werth, D.; Chiswell, S.; Etherton, B.

    2011-05-10

    The High-Resolution Mid-Atlantic Forecasting Ensemble (HME) is a federated effort to improve operational forecasts related to precipitation, convection and boundary layer evolution, and fire weather utilizing data and computing resources from a diverse group of cooperating institutions in order to create a mesoscale ensemble from independent members. Collaborating organizations involved in the project include universities, National Weather Service offices, and national laboratories, including the Savannah River National Laboratory (SRNL). The ensemble system is produced from an overlapping numerical weather prediction model domain and parameter subsets provided by each contributing member. The coordination, synthesis, and dissemination of the ensemble information are performed by the Renaissance Computing Institute (RENCI) at the University of North Carolina-Chapel Hill. This paper discusses background related to the HME effort, SRNL participation, and example results available from the RENCI website.

  9. Introduction of a Horizontal and Vertical Split Flow Model of Emergency Department Patients as a Response to Overcrowding.

    Science.gov (United States)

    Wallingford, Gregory; Joshi, Nikita; Callagy, Patrice; Stone, Jamie; Brown, Ian; Shen, Sam

    2017-11-20

    ED overcrowding is an issue that is affecting every emergency department and every hospital. The inability to maintain patient flow into and out of the emergency department paralyzes the ability to provide effective and timely patient care. Many solutions have been proposed on how to mitigate the effects of ED overcrowding. Solutions involve either hospital-wide initiatives or ED-based solutions. In this article, the authors seek to describe and provide metrics for a patient flow methodology that targets ESI 3 patients in a vertical flow model. In the Stanford Emergency Department, a vertical flow model was created from existing ED space by removing fold-down horizontal stretchers and replacing them with multiple chairs that allowed for assessment and medical management in an upright sitting position. The model was launched and sustained through frequent interdisciplinary huddles, detailed inclusion and exclusion criteria, scripted text on how to promote the flow model to patients, and close analytics of metrics. Metrics for success included patient length of stay (LOS) for those triaged to the vertical flow area compared with ESI 3 patients triaged to the traditional emergency department as a comparison group. The secondary outcome is the total number of patients seen in the vertical flow area. This was a 6-month-September 2014, to February 2015-retrospective pre- and postintervention study that examined LOS as a marker for effective launch and implementation of a vertical patient workflow model. The patients triaged to the vertical flow area in the study period tended to be younger than in the control period (43 years versus 52 years, P = 0.00). There was a significant decrease in our primary end point: the total LOS for ESI 3 patients triaged to the vertical flow area (270 minutes versus 384 minutes, P = 0.00). Implementation of a vertical patient flow strategy can decrease LOS for the vertical ESI 3 patients based upon the inclusion and exclusion criteria

  10. A high-resolution European dataset for hydrologic modeling

    Science.gov (United States)

    Ntegeka, Victor; Salamon, Peter; Gomes, Goncalo; Sint, Hadewij; Lorini, Valerio; Thielen, Jutta

    2013-04-01

    There is an increasing demand for large scale hydrological models not only in the field of modeling the impact of climate change on water resources but also for disaster risk assessments and flood or drought early warning systems. These large scale models need to be calibrated and verified against large amounts of observations in order to judge their capabilities to predict the future. However, the creation of large scale datasets is challenging for it requires collection, harmonization, and quality checking of large amounts of observations. For this reason, only a limited number of such datasets exist. In this work, we present a pan European, high-resolution gridded dataset of meteorological observations (EFAS-Meteo) which was designed with the aim to drive a large scale hydrological model. Similar European and global gridded datasets already exist, such as the HadGHCND (Caesar et al., 2006), the JRC MARS-STAT database (van der Goot and Orlandi, 2003) and the E-OBS gridded dataset (Haylock et al., 2008). However, none of those provide similarly high spatial resolution and/or a complete set of variables to force a hydrologic model. EFAS-Meteo contains daily maps of precipitation, surface temperature (mean, minimum and maximum), wind speed and vapour pressure at a spatial grid resolution of 5 x 5 km for the time period 1 January 1990 - 31 December 2011. It furthermore contains calculated radiation, which is calculated by using a staggered approach depending on the availability of sunshine duration, cloud cover and minimum and maximum temperature, and evapotranspiration (potential evapotranspiration, bare soil and open water evapotranspiration). The potential evapotranspiration was calculated using the Penman-Monteith equation with the above-mentioned meteorological variables. The dataset was created as part of the development of the European Flood Awareness System (EFAS) and has been continuously updated throughout the last years. The dataset variables are used as

  11. Modeling, design, packing and experimental analysis of liquid-phase shear-horizontal surface acoustic wave sensors

    Science.gov (United States)

    Pollard, Thomas B

    Recent advances in microbiology, computational capabilities, and microelectromechanical-system fabrication techniques permit modeling, design, and fabrication of low-cost, miniature, sensitive and selective liquid-phase sensors and lab-on-a-chip systems. Such devices are expected to replace expensive, time-consuming, and bulky laboratory-based testing equipment. Potential applications for devices include: fluid characterization for material science and industry; chemical analysis in medicine and pharmacology; study of biological processes; food analysis; chemical kinetics analysis; and environmental monitoring. When combined with liquid-phase packaging, sensors based on surface-acoustic-wave (SAW) technology are considered strong candidates. For this reason such devices are focused on in this work; emphasis placed on device modeling and packaging for liquid-phase operation. Regarding modeling, topics considered include mode excitation efficiency of transducers; mode sensitivity based on guiding structure materials/geometries; and use of new piezoelectric materials. On packaging, topics considered include package interfacing with SAW devices, and minimization of packaging effects on device performance. In this work novel numerical models are theoretically developed and implemented to study propagation and transduction characteristics of sensor designs using wave/constitutive equations, Green's functions, and boundary/finite element methods. Using developed simulation tools that consider finite-thickness of all device electrodes, transduction efficiency for SAW transducers with neighboring uniform or periodic guiding electrodes is reported for the first time. Results indicate finite electrode thickness strongly affects efficiency. Using dense electrodes, efficiency is shown to approach 92% and 100% for uniform and periodic electrode guiding, respectively; yielding improved sensor detection limits. A numerical sensitivity analysis is presented targeting viscosity

  12. Lexical ambiguity resolution for Turkish in direct transfer machine translation models

    OpenAIRE

    Tantuğ, A. Cüneyd; Tantug, A. Cuneyd; Oflazer, Kemal; Adalı, Eşref; Adali, Esref

    2006-01-01

    This paper presents a statistical lexical ambiguity resolution method in direct transfer machine translation models in which the target language is Turkish. Since direct transfer MT models do not have full syntactic information, most of the lexical ambiguity resolution methods are not very helpful. Our disambiguation model is based on statistical language models. We have investigated the performances of some statistical language model types and parameters in lexical ambiguity resolution for o...

  13. Nitrogen Removal in a Horizontal Subsurface Flow Constructed Wetland Estimated Using the First-Order Kinetic Model

    Directory of Open Access Journals (Sweden)

    Lijuan Cui

    2016-11-01

    Full Text Available We monitored the water quality and hydrological conditions of a horizontal subsurface constructed wetland (HSSF-CW in Beijing, China, for two years. We simulated the area-based constant and the temperature coefficient with the first-order kinetic model. We examined the relationships between the nitrogen (N removal rate, N load, seasonal variations in the N removal rate, and environmental factors—such as the area-based constant, temperature, and dissolved oxygen (DO. The effluent ammonia (NH4+-N and nitrate (NO3−-N concentrations were significantly lower than the influent concentrations (p < 0.01, n = 38. The NO3−-N load was significantly correlated with the removal rate (R2 = 0.96, p < 0.01, but the NH4+-N load was not correlated with the removal rate (R2 = 0.02, p > 0.01. The area-based constants of NO3−-N and NH4+-N at 20 °C were 27 ± 26 (mean ± SD and 14 ± 10 m∙year−1, respectively. The temperature coefficients for NO3−-N and NH4+-N were estimated at 1.004 and 0.960, respectively. The area-based constants for NO3−-N and NH4+-N were not correlated with temperature (p > 0.01. The NO3−-N area-based constant was correlated with the corresponding load (R2 = 0.96, p < 0.01. The NH4+-N area rate was correlated with DO (R2 = 0.69, p < 0.01, suggesting that the factors that influenced the N removal rate in this wetland met Liebig’s law of the minimum.

  14. Modeling of Arctic Storms with a Variable High-Resolution General Circulation Model

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Mark A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roesler, Erika Louise [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bosler, Peter Andrew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    The Department of Energy’s (DOE) Biological and Environmental Research project, “Water Cycle and Climate Extremes Modeling” is improving our understanding and modeling of regional details of the Earth’s water cycle. Sandia is using high resolution model behavior to investigate storms in the Arctic.

  15. A computational model for estimating the mechanics of horizontal flapping flight in bats: model description and validation.

    Science.gov (United States)

    Watts, P; Mitchell, E J; Swartz, S M

    2001-08-01

    We combine three-dimensional descriptions of the movement patterns of the shoulder, elbow, carpus, third metacarpophalangeal joint and wingtip with a constant-circulation estimation of aerodynamic force to model the wing mechanics of the grey-headed flying fox (Pteropus poliocephalus) in level flight. Once rigorously validated, this computer model can be used to study diverse aspects of flight. In the model, we partitioned the wing into a series of chordwise segments and calculated the magnitude of segmental aerodynamic forces assuming an elliptical, spanwise distribution of circulation at the middle of the downstroke. The lift component of the aerodynamic force is typically an order of magnitude greater than the thrust component. The largest source of drag is induced drag, which is approximately an order of magnitude greater than body form and skin friction drag. Using this model and standard engineering beam theory, we calculate internal reaction forces, moments and stresses at the humeral and radial midshaft during flight. To assess the validity of our model, we compare the model-derived stresses with our previous in vivo empirical measurements of bone strain from P. poliocephalus in free flapping flight. Agreement between bone stresses from the simulation and those calculated from empirical strain measurements is excellent and suggests that the computer model captures a significant portion of the mechanics and aerodynamics of flight in this species.

  16. High Resolution Modelling of Crop Response to Climate Change

    Science.gov (United States)

    Mirmasoudi, S. S.; Byrne, J. M.; MacDonald, R. J.; Lewis, D.

    2014-12-01

    Crop production is one of the most vulnerable sectors to climatic variability and change. Increasing atmospheric CO2 concentration and other greenhouse gases are causing increases in global temperature. In western North America, water supply is largely derived from mountain snowmelt. Climate change will have a significant impact on mountain snowpack and subsequently, the snow-derived water supply. This will strain water supplies and increase water demand in areas with substantial irrigation agriculture. Increasing temperatures may create heat stress for some crops regardless of soil water supply, and increasing surface O3 and other pollutants may damage crops and ecosystems. CO2 fertilization may or may not be an advantage in future. This work is part of a larger study that will address a series of questions based on a range of future climate scenarios for several watersheds in western North America. The key questions are: (1) how will snowmelt and rainfall runoff vary in future; (2) how will seasonal and inter-annual soil water supply vary, and how might that impacts food supplies; (3) how might heat stress impact (some) crops even with adequate soil water; (4) will CO2 fertilization alter crop yields; and (5) will pollution loads, particularly O3, cause meaningful changes to crop yields? The Generate Earth Systems Science (GENESYS) Spatial Hydrometeorological Model is an innovative, efficient, high-resolution model designed to assess climate driven changes in mountain snowpack derived water supplies. We will link GENESYS to the CROPWAT crop model system to assess climate driven changes in water requirement and associated crop productivity for a range of future climate scenarios. Literature bases studies will be utilised to develop approximate crop response functions for heat stress, CO2 fertilization and for O3 damages. The overall objective is to create modeling systems that allows meaningful assessment of agricultural productivity at a watershed scale under a

  17. Optimal waste load allocation using graph model for conflict resolution.

    Science.gov (United States)

    Saberi, Leila; Niksokhan, Mohammad Hossein

    2017-03-01

    In this paper, a new methodology is proposed for waste load allocation in river systems using the decision support system (DSS) for the graph model for conflict resolution II (GMCRII), multi-criteria decision making (MCDM) analysis and the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm. Minimization of total treatment and penalty costs and minimization of biological oxygen demand violation of standards at the check point are considered as the main objectives of this study. At first, the water quality along the river was simulated using the Streeter-Phelps (S-P) equation coupled with the MOPSO model. Thereby a trade-off curve between the objectives is obtained and a set of non-dominated solutions is selected. In the next step, the best alternative is chosen using MCDM techniques and the GMCRII DSS package and non-cooperative stability definitions. The applicability and efficiency of the methodology are examined in a real-world case study of the Sefidrud River in the northern part of Iran.

  18. Hyper-resolution urban flood modeling using high-resolution radar precipitation and LiDAR data

    Science.gov (United States)

    Noh, S. J.; Lee, S.; Lee, J.; Seo, D. J.

    2016-12-01

    Floods occur most frequently among all natural hazards, often causing widespread economic damage and loss of human lives. In particular, urban flooding is becoming increasingly costly and difficult to manage with a greater concentration of population and assets in urban centers. Despite of known benefits for accurate representation of small scale features and flow interaction among different flow domains, which have significant impact on flood propagation, high-resolution modeling has not been fully utilized due to expensive computation and various uncertainties from model structure, input and parameters. In this study, we assess the potential of hyper-resolution hydrologic-hydraulic modeling using high-resolution radar precipitation and LiDAR data for improved urban flood prediction and hazard mapping. We describe a hyper-resolution 1D-2D coupled urban flood model for pipe and surface flows and evaluate the accuracy of the street-level inundation information produced. For detailed geometric representation of urban areas and for computational efficiency, we use 1 m-resolution topographical data, processed from LiDAR measurements, in conjunction with adaptive mesh refinement. For street-level simulation in large urban areas at grid sizes of 1 to 10 m, a hybrid parallel computing scheme using MPI and openMP is also implemented in a high-performance computing system. The modeling approach developed is applied for the Johnson Creek Catchment ( 40 km2), which makes up the Arlington Urban Hydroinformatics Testbed. In addition, discussion will be given on availability of hyper-resolution simulation archive for improved real-time flood mapping.

  19. The effect of a dragging anchor on a horizontal layer of rockfill : A Prototype and a Scale Model Test

    NARCIS (Netherlands)

    Crum, S.; Van der Hoeven, M.L.E.B.; Krouwel, L.P.H.C.; Verhagen, H.J.

    2015-01-01

    Quantifying the penetration depth of a dragging anchor on a horizontal layer of rockfill provides the possibility to optimize the layer thickness of rockfill layers with a protective function. Current research on this subject is limited and is often aimed at anchor capacities in sand and clay.

  20. A high-resolution ambient seismic noise model for Europe

    Science.gov (United States)

    Kraft, Toni

    2014-05-01

    measurement precision (i.e. earthquake location), while considering this extremely complex boundary condition. To solve this problem I have developed a high-resolution ambient seismic noise model for Europe. The model is based on land-use data derived from satellite imagery by the EU-project CORINE in a resolution of 100x100m. The the CORINE data consists of several land-use classes, which, besides others, contain: industrial areas, mines, urban fabric, agricultural areas, permanent corps, forests and open spaces. Additionally, open GIS data for highways, and major and minor roads and railway lines were included from the OpenStreetMap project (www.openstreetmap.org). This data was divided into three classes that represent good, intermediate and bad ambient conditions of the corresponding land-use class based on expert judgment. To account for noise propagation away from its source a smoothing operator was applied to individual land-use noise-fields. Finally, the noise-fields were stacked to obtain an European map of ambient noise conditions. A calibration of this map with data of existing seismic stations Europe allowed me to estimate the expected noise level in actual ground motion units for the three ambient noise condition classes of the map. The result is a high-resolution ambient seismic noise map, that allows the network designer to make educated predictions on the expected noise level for arbitrary location in Europe. The ambient noise model was successfully tested in several network optimization projects in Switzerland and surrounding countries and will hopefully be a valuable contribution to improving the data quality of microseismic monitoring networks in Europe.

  1. The internal gravity wave spectrum in two high-resolution global ocean models

    Science.gov (United States)

    Arbic, B. K.; Ansong, J. K.; Buijsman, M. C.; Kunze, E. L.; Menemenlis, D.; Müller, M.; Richman, J. G.; Savage, A.; Shriver, J. F.; Wallcraft, A. J.; Zamudio, L.

    2016-02-01

    We examine the internal gravity wave (IGW) spectrum in two sets of high-resolution global ocean simulations that are forced concurrently by atmospheric fields and the astronomical tidal potential. We analyze global 1/12th and 1/25th degree HYCOM simulations, and global 1/12th, 1/24th, and 1/48th degree simulations of the MITgcm. We are motivated by the central role that IGWs play in ocean mixing, by operational considerations of the US Navy, which runs HYCOM as an ocean forecast model, and by the impact of the IGW continuum on the sea surface height (SSH) measurements that will be taken by the planned NASA/CNES SWOT wide-swath altimeter mission. We (1) compute the IGW horizontal wavenumber-frequency spectrum of kinetic energy, and interpret the results with linear dispersion relations computed from the IGW Sturm-Liouville problem, (2) compute and similarly interpret nonlinear spectral kinetic energy transfers in the IGW band, (3) compute and similarly interpret IGW contributions to SSH variance, (4) perform comparisons of modeled IGW kinetic energy frequency spectra with moored current meter observations, and (5) perform comparisons of modeled IGW kinetic energy vertical wavenumber-frequency spectra with moored observations. This presentation builds upon our work in Muller et al. (2015, GRL), who performed tasks (1), (2), and (4) in 1/12th and 1/25th degree HYCOM simulations, for one region of the North Pacific. New for this presentation are tasks (3) and (5), the inclusion of MITgcm solutions, and the analysis of additional ocean regions.

  2. Complex mean circulation over the inner shelf south of Martha's Vineyard revealed by observations and a high-resolution model

    Science.gov (United States)

    Ganju, Neil K.; Lentz, Steven J.; Kirincich, Anthony R.; Farrar, J. Thomas

    2011-01-01

    Inner-shelf circulation is governed by the interaction between tides, baroclinic forcing, winds, waves, and frictional losses; the mean circulation ultimately governs exchange between the coast and ocean. In some cases, oscillatory tidal currents interact with bathymetric features to generate a tidally rectified flow. Recent observational and modeling efforts in an overlapping domain centered on the Martha's Vineyard Coastal Observatory (MVCO) provided an opportunity to investigate the spatial and temporal complexity of circulation on the inner shelf. ADCP and surface radar observations revealed a mean circulation pattern that was highly variable in the alongshore and cross-shore directions. Nested modeling incrementally improved representation of the mean circulation as grid resolution increased and indicated tidal rectification as the generation mechanism of a counter-clockwise gyre near the MVCO. The loss of model skill with decreasing resolution is attributed to insufficient representation of the bathymetric gradients (Δh/h), which is important for representing nonlinear interactions between currents and bathymetry. The modeled momentum balance was characterized by large spatial variability of the pressure gradient and horizontal advection terms over short distances, suggesting that observed inner-shelf momentum balances may be confounded. Given the available observational and modeling data, this work defines the spatially variable mean circulation and its formation mechanism—tidal rectification—and illustrates the importance of model resolution for resolving circulation and constituent exchange near the coast. The results of this study have implications for future observational and modeling studies near the MVCO and other inner-shelf locations with alongshore bathymetric variability.

  3. Blending process modeling and control by multivariate curve resolution.

    Science.gov (United States)

    Jaumot, J; Igne, B; Anderson, C A; Drennen, J K; de Juan, A

    2013-12-15

    The application of the Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) method to model and control blend processes of pharmaceutical formulations is assessed. Within the MCR-ALS framework, different data analysis approaches have been tested depending on the objective of the study, i.e., knowing the effect of different factors in the evolution of the blending process (modeling) or detecting the blend end-point and monitoring the concentration of the different species during and at the end of the process (control). Data analysis has been carried out studying multiple blending runs simultaneously taking advantage of the multiset mode of the MCR-ALS method. During the ALS optimization, natural constraints, such as non-negativity (spectral and concentration directions) have been applied for blend modeling. When blending control is the main purpose, a variant of the MCR-ALS algorithm with correlation constraint in the concentration direction has been additionally used. This constraint incorporates an internal calibration procedure, which relates resolved concentration values (in arbitrary units) with the real reference concentration values in the calibration samples (known references) providing values in real concentration scale in the final MCR-ALS results. Two systems consisting of pharmaceutical mixtures of an active principle (acetaminophen) with two or four excipients have been investigated. In the first case, MCR results allowed the description of the evolution of the individual compounds and the assessment of some physical effects in the blending process. In the second case, MCR analysis allowed the detection of the end-point of the process and the assessment of the effects linked to variations in the concentration level of the compounds. © 2013 Elsevier B.V. All rights reserved.

  4. Analysis and high resolution modelling of black carbon vertical profiles measured over three Italian valleys

    Science.gov (United States)

    Gandolfi, Ilaria; Curci, Gabriele; Falasca, Serena; Ferrero, Luca

    2017-04-01

    Analysis and high resolution modelling of black carbon vertical profiles measured over three Italian valleys Ilaria Gandolfi1,2, Gabriele Curci1,2, Serena Falasca1,2, Luca Ferrero3 1 Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy 2 Center of Excellence CETEMPS, University of L'Aquila, L'Aquila, Italy 3 POLARIS Research Centre, Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126, Milan, Italy Last decades were characterized by a growing interest in aerosols: mainly for their effect on human health and on the energy balance of solar and planetary radiation, thus their role in climate change. In this study, we analyze the evolution of vertical profile of black carbon (BC) through tethered balloon observations and chemistry-transport modelling. Black carbon is regarded as the second most important anthropogenic climate forcing agent and its concentration varies significantly depending on the altitude and the sources on the territory. In winter of 2010 University Of Milan Bicocca conducted three intensive measurements campaigns over three Italian basin valleys (Terni, Po Valley, Passiria Valley). The choice of the valleys was made taking into consideration the orography and the river basin structure. The measurement campaign was based on a helium-filled tethered balloon, on which the instrumentation for the analysis has been mounted; the instrumentation consisted on a meteorological station, an OPC, a cascade impactor and a micro-Aethalometer. Subsequently, at University of L'Aquila simulations were produced to help interpretation of these vertical aerosol profiles (mass, composition and distribution) and related optical properties (scattering, absorption) using a chemistry-transport model (WRF-CHIMERE) at high horizontal resolution (1 km). The analysis focused primarily on the calculation of the heating rate and of the Direct Radiative Effect (DRE), and on the analysis of the

  5. High Resolution Downscaling For Mesoamerica And The Caribbean Of CMIP5 Global Model Simulations: Identifying Vulnerability And Adaptation Needs

    Science.gov (United States)

    Oglesby, R. J.; Rowe, C. M.; Hays, C.

    2012-12-01

    High-resolution (4-12 km) dynamical downscaling simulations of future climate change between now and 2060 have been made for Mesoamerica and the Caribbean. We use the Weather Research and Forecasting (WRF) regional climate model to downscale results from the NCAR CCSM4 CMIP5 RCP8.5 global simulation. The entire region is covered at 12 km horizontal spatial resolution, with as much as possible (especially in mountainous regions) at 4 km. We compare a control period (2006-2010) with 50 years into the future (2056-2060). The motivation for making these computationally-demanding model simulations is to better define local and regional climate change effects so as to better identify and quantify impacts and associated vulnerabilities. This is an essential precursor to developing robust adaptation strategies. These simulations have been made in conjunction with our partners from the countries involved. As expected, all areas warm, with the warming in general largest in inland regions, and less towards coastal regions. Higher elevation regions also tend to warm somewhat more than lower elevation regions, a result that could not be reliably obtained, in detail, from coarse-scale global models. The precipitation signal is much more mixed, and demonstrates more clearly the need for high resolution. The effects of changes in the large-scale trade wind regime tend to be restricted to the immediate Atlantic coast, while the interior is less-well posed, with some indication of a northward shift in precipitation regime, due to changes both in the large-scale ITCZ, and the regional scale Caribbean and Gulf of Mexico low-level jets. Topographic resolution continues to play a key role. The new results are currently being used by both climate scientists and policy makers to evaluate vulnerabilities, and hence develop adaptation strategies for the affected countries.

  6. Investigation of gravity waves using horizontally resolved radial velocity measurements

    Science.gov (United States)

    Stober, G.; Sommer, S.; Rapp, M.; Latteck, R.

    2013-10-01

    The Middle Atmosphere Alomar Radar System (MAARSY) on the island of Andøya in Northern Norway (69.3° N, 16.0° E) observes polar mesospheric summer echoes (PMSE). These echoes are used as tracers of atmospheric dynamics to investigate the horizontal wind variability at high temporal and spatial resolution. MAARSY has the capability of pulse-to-pulse beam steering allowing for systematic scanning experiments to study the horizontal structure of the backscatterers as well as to measure the radial velocities for each beam direction. Here we present a method to retrieve gravity wave parameters from these horizontally resolved radial wind variations by applying velocity azimuth display and volume velocity processing. Based on the observations a detailed comparison of the two wind analysis techniques is carried out in order to determine the zonal and meridional wind as well as to measure first-order inhomogeneities. Further, we demonstrate the possibility to resolve the horizontal wave properties, e.g., horizontal wavelength, phase velocity and propagation direction. The robustness of the estimated gravity wave parameters is tested by a simple atmospheric model.

  7. Investigation of gravity waves using horizontally resolved radial velocity measurements

    Directory of Open Access Journals (Sweden)

    G. Stober

    2013-10-01

    Full Text Available The Middle Atmosphere Alomar Radar System (MAARSY on the island of Andøya in Northern Norway (69.3° N, 16.0° E observes polar mesospheric summer echoes (PMSE. These echoes are used as tracers of atmospheric dynamics to investigate the horizontal wind variability at high temporal and spatial resolution. MAARSY has the capability of pulse-to-pulse beam steering allowing for systematic scanning experiments to study the horizontal structure of the backscatterers as well as to measure the radial velocities for each beam direction. Here we present a method to retrieve gravity wave parameters from these horizontally resolved radial wind variations by applying velocity azimuth display and volume velocity processing. Based on the observations a detailed comparison of the two wind analysis techniques is carried out in order to determine the zonal and meridional wind as well as to measure first-order inhomogeneities. Further, we demonstrate the possibility to resolve the horizontal wave properties, e.g., horizontal wavelength, phase velocity and propagation direction. The robustness of the estimated gravity wave parameters is tested by a simple atmospheric model.

  8. High-resolution modeling of protein structures based on flexible fitting of low-resolution structural data.

    Science.gov (United States)

    Zheng, Wenjun; Tekpinar, Mustafa

    2014-01-01

    To circumvent the difficulty of directly solving high-resolution biomolecular structures, low-resolution structural data from Cryo-electron microscopy (EM) and small angle solution X-ray scattering (SAXS) are increasingly used to explore multiple conformational states of biomolecular assemblies. One promising venue to obtain high-resolution structural models from low-resolution data is via data-constrained flexible fitting. To this end, we have developed a new method based on a coarse-grained Cα-only protein representation, and a modified form of the elastic network model (ENM) that allows large-scale conformational changes while maintaining the integrity of local structures including pseudo-bonds and secondary structures. Our method minimizes a pseudo-energy which linearly combines various terms of the modified ENM energy with an EM/SAXS-fitting score and a collision energy that penalizes steric collisions. Unlike some previous flexible fitting efforts using the lowest few normal modes, our method effectively utilizes all normal modes so that both global and local structural changes can be fully modeled with accuracy. This method is also highly efficient in computing time. We have demonstrated our method using adenylate kinase as a test case which undergoes a large open-to-close conformational change. The EM-fitting method is available at a web server (http://enm.lobos.nih.gov), and the SAXS-fitting method is available as a pre-compiled executable upon request. © 2014 Elsevier Inc. All rights reserved.

  9. Numerical Investigation on the Heat Extraction Capacity of Dual Horizontal Wells in Enhanced Geothermal Systems Based on the 3-D THM Model

    Directory of Open Access Journals (Sweden)

    Zhixue Sun

    2018-01-01

    Full Text Available The Enhanced Geothermal System (EGS constructs an artificial thermal reservoir by hydraulic fracturing to extract heat economically from hot dry rock. As the core element of the EGS heat recovery process, mass and heat transfer of working fluid mainly occurs in fractures. Since the direction of the natural and induced fractures are generally perpendicular to the minimum principal stress in the formation, as an effective stimulation approach, horizontal well production could increase the contact area with the thermal reservoir significantly. In this paper, the thermal reservoir is developed by a dual horizontal well system and treated as a fractured porous medium composed of matrix rock and discrete fracture network. Using the local thermal non-equilibrium theory, a coupled THM mathematical model and an ideal 3D numerical model are established for the EGS heat extraction process. EGS heat extraction capacity is evaluated in the light of thermal recovery lifespan, average outlet temperature, heat production, electricity generation, energy efficiency and thermal recovery rate. The results show that with certain reservoir and production parameters, the heat production, electricity generation and thermal recovery lifespan can achieve the commercial goal of the dual horizontal well system, but the energy efficiency and overall thermal recovery rate are still at low levels. At last, this paper puts forward a series of optimizations to improve the heat extraction capacity, including production conditions and thermal reservoir construction design.

  10. Demonstration of Effects on Tropical Cyclone Forecasts with a High Resolution Global Model from Variation in Cumulus Convection Parameterization

    Science.gov (United States)

    Miller, Timothy L.; Robertson, Franklin R.; Cohen, Charles; Mackaro, Jessica

    2009-01-01

    The Goddard Earth Observing System Model, Version 5 (GEOS-5) is a system of models that have been developed at Goddard Space Flight Center to support NASA's earth science research in data analysis, observing system modeling and design, climate and weather prediction, and basic research. The work presented used GEOS-5 with 0.25o horizontal resolution and 72 vertical levels (up to 0.01 hP) resolving both the troposphere and stratosphere, with closer packing of the levels close to the surface. The model includes explicit (grid-scale) moist physics, as well as convective parameterization schemes. Results will be presented that will demonstrate strong dependence in the results of modeling of a strong hurricane on the type of convective parameterization scheme used. The previous standard (default) option in the model was the Relaxed Arakawa-Schubert (RAS) scheme, which uses a quasi-equilibrium closure. In the cases shown, this scheme does not permit the efficient development of a strong storm in comparison with observations. When this scheme is replaced by a modified version of the Kain-Fritsch scheme, which was originally developed for use on grids with intervals of order 25 km such as the present one, the storm is able to develop to a much greater extent, closer to that of reality. Details of the two cases will be shown in order to elucidate the differences in the two modeled storms.

  11. Arctic storms simulated in atmospheric general circulation models under uniform high, uniform low, and variable resolutions

    Science.gov (United States)

    Roesler, E. L.; Bosler, P. A.; Taylor, M.

    2016-12-01

    The impact of strong extratropical storms on coastal communities is large, and the extent to which storms will change with a warming Arctic is unknown. Understanding storms in reanalysis and in climate models is important for future predictions. We know that the number of detected Arctic storms in reanalysis is sensitive to grid resolution. To understand Arctic storm sensitivity to resolution in climate models, we describe simulations designed to identify and compare Arctic storms at uniform low resolution (1 degree), at uniform high resolution (1/8 degree), and at variable resolution (1 degree to 1/8 degree). High-resolution simulations resolve more fine-scale structure and extremes, such as storms, in the atmosphere than a uniform low-resolution simulation. However, the computational cost of running a globally uniform high-resolution simulation is often prohibitive. The variable resolution tool in atmospheric general circulation models permits regional high-resolution solutions at a fraction of the computational cost. The storms are identified using the open-source search algorithm, Stride Search. The uniform high-resolution simulation has over 50% more storms than the uniform low-resolution and over 25% more storms than the variable resolution simulations. Storm statistics from each of the simulations is presented and compared with reanalysis. We propose variable resolution as a cost-effective means of investigating physics/dynamics coupling in the Arctic environment. Future work will include comparisons with observed storms to investigate tuning parameters for high resolution models. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2016-7402 A

  12. Production of solar radiation bankable datasets from high-resolution solar irradiance derived with dynamical downscaling Numerical Weather prediction model

    Directory of Open Access Journals (Sweden)

    Yassine Charabi

    2016-11-01

    Full Text Available A bankable solar radiation database is required for the financial viability of solar energy project. Accurate estimation of solar energy resources in a country is very important for proper siting, sizing and life cycle cost analysis of solar energy systems. During the last decade an important progress has been made to develop multiple solar irradiance database (Global Horizontal Irradiance (GHI and Direct Normal Irradiance (DNI, using satellite of different resolution and sophisticated models. This paper assesses the performance of High-resolution solar irradiance derived with dynamical downscaling Numerical Weather Prediction model with, GIS topographical solar radiation model, satellite data and ground measurements, for the production of bankable solar radiation datasets. For this investigation, NWP model namely Consortium for Small-scale Modeling (COSMO is used for the dynamical downscaling of solar radiation. The obtained results increase confidence in solar radiation data base obtained from dynamical downscaled NWP model. The mean bias of dynamical downscaled NWP model is small, on the order of a few percents for GHI, and it could be ranked as a bankable datasets. Fortunately, these data are usually archived in the meteorological department and gives a good idea of the hourly, monthly, and annual incident energy. Such short time-interval data are valuable in designing and operating the solar energy facility. The advantage of the NWP model is that it can be used for solar radiation forecast since it can estimate the weather condition within the next 72–120 hours. This gives a reasonable estimation of the solar radiation that in turns can be used to forecast the electric power generation by the solar power plant.

  13. Estimates of Climate Change Impact on River Discharge in Japan Based on a Super-High-Resolution Climate Model

    Directory of Open Access Journals (Sweden)

    Yoshinobu Sato

    2012-01-01

    Full Text Available The impact of climate change on river discharge was assessed by hydrological simulations for several major river basins in Japan using the latest version of a super-high-resolution atmospheric general circulation model (AGCM with a horizontal resolution of about 20 km. Projections were made using two different datasets, one representing the present climate (1980 - 1999 and the other representing the end of the 21st century (2080 - 2099 assuming the SRES A1B scenario. River discharge was estimated by a distributed hydrological model calibrated against observed river discharge in advance. The results showed that even if the amount of precipitation does not change much in the future, river discharge will change significantly because of the increase in rainfall, decrease in snowmelt, and increase in evapotranspiration with higher air temperature. The impact of climate change on river discharge will be more significant in the northern part of Japan, especially in the Tohoku and Hokuriku regions. In these regions, the monthly average river discharge at the end of the 21st century was projected to be more than 200% higher in February and approximately 50 - 60% lower in May compared with the present flow. These results imply that the increase in air temperature has important consequences for the hydrological cycle, particularly in regions where the water supply is currently dominated by snowmelt.

  14. Oil-material fractionation in Gulf deep water horizontal intrusion layer: Field data analysis with chemodynamic fate model for Macondo 252 oil spill.

    Science.gov (United States)

    Melvin, A T; Thibodeaux, L J; Parsons, A R; Overton, E; Valsaraj, K T; Nandakumar, K

    2016-04-15

    Among the discoveries of the Deepwater Horizon blowout was the so-called "sub-surface plume"; herein termed the "oil-trapping layer". Hydrocarbons were found positioned at ~1100-1300m with thickness ~100-150m and moving horizontally to the SW in a vertically stratified layer at the junction of the cold abyssal water and the permanent thermocline. This study focuses on its formation process and fate of the hydrocarbons within. The originality of this work to the field is two-fold, first it provides a conceptual framework which places layer origin in the context of a horizontal "intrusion" from the near-field, vertical, blow-out plume and second, it offers a theoretical model for the hydrocarbon chemicals within the horizontal layer as it moves far-afield. The model quantifies the oil-material fractionation process for the soluble and fine particle. The classical Box model, retrofitted with an internal gradient, the "G-Box", allows an approach that includes turbulent eddy diffusion coupled with droplet rise velocity and reactive decay to produce a simple, explicit, transparent, algebraic model with few parameters for the fate of the individual fractions. Computations show the soluble and smallest liquid droplets moving very slowly vertically through the layer appearing within the trapping layer at low concentration with high persistence. The larger droplets move-through this trapping zone quickly, attain high concentrations, and eventually form the sea surface slick. It impacts the field of oil spill engineering science by providing the conceptual idea and the algorithms for projecting the quantities and fractions of oil-material in a deep water, horizontal marine current being dispersed and moving far afield. In the field of oil spill modeling this work extends the current generation near-field plume source models to the far-field. The theory portrays the layer as an efficient oil-material trap. The model-forecasted concentration profiles for alkanes and aromatics

  15. Vertical binocular disparity is encoded implicitly within a model neuronal population tuned to horizontal disparity and orientation.

    Directory of Open Access Journals (Sweden)

    Jenny C A Read

    2010-04-01

    Full Text Available Primary visual cortex is often viewed as a "cyclopean retina", performing the initial encoding of binocular disparities between left and right images. Because the eyes are set apart horizontally in the head, binocular disparities are predominantly horizontal. Yet, especially in the visual periphery, a range of non-zero vertical disparities do occur and can influence perception. It has therefore been assumed that primary visual cortex must contain neurons tuned to a range of vertical disparities. Here, I show that this is not necessarily the case. Many disparity-selective neurons are most sensitive to changes in disparity orthogonal to their preferred orientation. That is, the disparity tuning surfaces, mapping their response to different two-dimensional (2D disparities, are elongated along the cell's preferred orientation. Because of this, even if a neuron's optimal 2D disparity has zero vertical component, the neuron will still respond best to a non-zero vertical disparity when probed with a sub-optimal horizontal disparity. This property can be used to decode 2D disparity, even allowing for realistic levels of neuronal noise. Even if all V1 neurons at a particular retinotopic location are tuned to the expected vertical disparity there (for example, zero at the fovea, the brain could still decode the magnitude and sign of departures from that expected value. This provides an intriguing counter-example to the common wisdom that, in order for a neuronal population to encode a quantity, its members must be tuned to a range of values of that quantity. It demonstrates that populations of disparity-selective neurons encode much richer information than previously appreciated. It suggests a possible strategy for the brain to extract rarely-occurring stimulus values, while concentrating neuronal resources on the most commonly-occurring situations.

  16. Validation of high-resolution aerosol optical thickness simulated by a global non-hydrostatic model against remote sensing measurements

    Science.gov (United States)

    Goto, Daisuke; Sato, Yousuke; Yashiro, Hisashi; Suzuki, Kentaroh; Nakajima, Teruyuki

    2017-02-01

    A high-performance computing resource allows us to conduct numerical simulations with a horizontal grid spacing that is sufficiently high to resolve cloud systems. The cutting-edge computational capability, which was provided by the K computer at RIKEN in Japan, enabled the authors to perform long-term, global simulations of air pollutions and clouds with unprecedentedly high horizontal resolutions. In this study, a next generation model capable of simulating global air pollutions with O(10 km) grid spacing by coupling an atmospheric chemistry model to the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) was performed. Using the newly developed model, month-long simulations for July were conducted with 14 km grid spacing on the K computer. Regarding the global distributions of aerosol optical thickness (AOT), it was found that the correlation coefficient (CC) between the simulation and AERONET measurements was approximately 0.7, and the normalized mean bias was -10%. The simulated AOT was also compared with satellite-retrieved values; the CC was approximately 0.6. The radiative effects due to each chemical species (dust, sea salt, organics, and sulfate) were also calculated and compared with multiple measurements. As a result, the simulated fluxes of upward shortwave radiation at the top of atmosphere and the surface compared well with the observed values, whereas those of downward shortwave radiation at the surface were underestimated, even if all aerosol components were considered. However, the aerosol radiative effects on the downward shortwave flux at the surface were found to be as high as 10 W/m2 in a global scale; thus, simulated aerosol distributions can strongly affect the simulated air temperature and dynamic circulation.

  17. High-resolution numerical modeling of meteorological and hydrological conditions during May 2014 floods in Serbia

    Science.gov (United States)

    Vujadinovic, Mirjam; Vukovic, Ana; Cvetkovic, Bojan; Pejanovic, Goran; Nickovic, Slobodan; Djurdjevic, Vladimir; Rajkovic, Borivoj; Djordjevic, Marija

    2015-04-01

    In May 2014 west Balkan region was affected by catastrophic floods in Serbia, Bosnia and Herzegovina and eastern parts of Croatia. Observed precipitation amount were extremely high, on many stations largest ever recorded. In the period from 12th to 18th of May, most of Serbia received between 50 to 100 mm of rainfall, while western parts of the country, which were influenced the most, had over 200 mm of rainfall, locally even more than 300 mm. This very intense precipitation came when the soil was already saturated after a very wet period during the second half of April and beginning of May, when most of Serbia received between 120 i 170 mm of rainfall. New abundant precipitation on already saturated soil increased surface and underground water flow, caused floods, soil erosion and landslides. High water levels, most of them record breaking, were measured on the Sava, Drina, Dunav, Kolubara, Ljig, Ub, Toplica, Tamnava, Jadar, Zapadna Morava, Velika Morava, Mlava and Pek river. Overall, two cities and 17 municipals were severely affected by the floods, 32000 people were evacuated from their homes, while 51 died. Material damage to the infrastructure, energy power system, crops, livestock funds and houses is estimated to more than 2 billion euro. Although the operational numerical weather forecast gave in generally good precipitation prediction, flood forecasting in this case was mainly done through the expert judgment rather than relying on dynamic hydrological modeling. We applied an integrated atmospheric-hydrologic modelling system to some of the most impacted catchments in order to timely simulate hydrological response, and examine its potentials as a flood warning system. The system is based on the Non-hydrostatic Multiscale Model NMMB, which is a numerical weather prediction model that can be used on a broad range of spatial and temporal scales. Its non-hydrostatic module allows high horizontal resolution and resolving cloud systems as well as large

  18. Influence of air quality model resolution on uncertainty associated with health impacts

    Directory of Open Access Journals (Sweden)

    T. M. Thompson

    2012-10-01

    Full Text Available We use regional air quality modeling to evaluate the impact of model resolution on uncertainty associated with the human health benefits resulting from proposed air quality regulations. Using a regional photochemical model (CAMx, we ran a modeling episode with meteorological inputs simulating conditions as they occurred during August through September 2006 (a period representative of conditions leading to high ozone, and two emissions inventories (a 2006 base case and a 2018 proposed control scenario, both for Houston, Texas at 36, 12, 4 and 2 km resolution. The base case model performance was evaluated for each resolution against daily maximum 8-h averaged ozone measured at monitoring stations. Results from each resolution were more similar to each other than they were to measured values. Population-weighted ozone concentrations were calculated for each resolution and applied to concentration response functions (with 95% confidence intervals to estimate the health impacts of modeled ozone reduction from the base case to the control scenario. We found that estimated avoided mortalities were not significantly different between the 2, 4 and 12 km resolution runs, but the 36 km resolution may over-predict some potential health impacts. Given the cost/benefit analysis requirements motivated by Executive Order 12866 as it applies to the Clean Air Act, the uncertainty associated with human health impacts and therefore the results reported in this study, we conclude that health impacts calculated from population weighted ozone concentrations obtained using regional photochemical models at 36 km resolution fall within the range of values obtained using fine (12 km or finer resolution modeling. However, in some cases, 36 km resolution may not be fine enough to statistically replicate the results achieved using 2, 4 or 12 km resolution. On average, when modeling at 36 km resolution, an estimated 5 deaths per week during the May through September ozone

  19. Horizontal Equity, Once More

    OpenAIRE

    Musgrave, Richard A.

    1990-01-01

    Reconsiders the proposition that vertical equity is the primary norm for tax design, with horizontal equity a mere derivative therefrom. In the case of limited policy options, vertical and horizontal equity goals may conflict so that a trade-off will be needed. Independent values must then be assigned to each, confirming the standing of a horizontal as well as vertical equity as a primary norm.

  20. High resolution forecast of heavy precipitation with Lokal Modell: analysis of two case studies in the Alpine area

    Directory of Open Access Journals (Sweden)

    M. Elementi

    2005-01-01

    Full Text Available Northern Italy is frequently affected by severe precipitation conditions often inducing flood events with associated loss of properties, damages and casualties. The capability of correctly forecast these events, strongly required for an efficient support to civil protection actions, is still nowadays a challenge. This difficulty is also related with the complex structure of the precipitation field in the Alpine area and, more generally, over the Italian territory. Recently a new generation of non-hydrostatic meteorological models, suitable to be used at very high spatial resolution, has been developed. In this paper the performance of the non-hydrostatic Lokal Modell developed by the COSMO Consortium, is analysed with regard to a couple of intense precipitation events occurred in the Piemonte region in Northern Italy. These events were selected among the reference cases of the Hydroptimet/INTERREG IIIB project. LM run at the operational resolution of 7km provides a good forecast of the general rain structure, with an unsatisfactory representation of the precipitation distribution across the mountain ranges. It is shown that the inclusion of the new prognostic equations for cloud ice, rain and snow produces a remarkable improvement, reducing the precipitation in the upwind side and extending the intense rainfall area to the downwind side. The unrealistic maxima are decreased towards observed values. The use of very high horizontal resolution (2.8 km improves the general shape of the precipitation field in the flat area of the Piemonte region but, keeping active the moist convection scheme, sparse and more intense rainfall peaks are produced. When convective precipitation is not parametrised but explicitly represented by the model, this negative effect is removed.

  1. Inter-generational micro-class mobility during and after socialism: The power, education, autonomy, capital, and horizontal (PEACH) model in Hungary.

    Science.gov (United States)

    Lippényi, Zoltán; Gerber, Theodore P

    2016-07-01

    We propose a theoretical model of how occupational mobility operates differently under socialism than under market regimes. Our model specifies four vertical dimensions of occupational resources-power, education, autonomy, and capital-plus a horizontal dimension consisting of linkages among occupations in the same economic branch. Given the nature of state socialist political-economic institutions, we expect power to exhibit much stronger effects in the socialist mobility regime, while autonomy and capital should play greater stratifying roles after the market transition. Education should have stable effects, and horizontal linkages should diminish in strength with market reforms. We estimate our model's parameters using data from surveys conducted in Hungary during and after the socialist period. We adopt a micro-class approach, though we test it against approaches that use more aggregated class categories. Our model provides a superior fit to other mobility models, and our results confirm our hypotheses about the distinctive features of the state socialist mobility regime. Mobility researchers often look for common patterns characterizing mobility in all industrialized societies. Our findings suggest that national institutions can produce fundamentally distinct patterns of mobility. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. A Comprehensive School-based Conflict-Resolution Model.

    Science.gov (United States)

    Woody, Debra

    2001-01-01

    Describes a comprehensive school-based conflict-resolution approach designed by two school-based social workers and implemented in an "alternative" urban high school over a two-year period. Results indicate that a more cooperative atmosphere developed in the school as a result of the program and that the program was effective in reducing both…

  3. High-resolution modelling of health impacts from air pollution using the integrated model system EVA

    Science.gov (United States)

    Brandt, Jørgen; Andersen, Mikael S.; Bønløkke, Jakob; Christensen, Jesper H.; Geels, Camilla; Hansen, Kaj M.; Jensen, Steen S.; Ketzel, Matthias; Plejdrup, Marlene S.; Sigsgaard, Torben; Silver, Jeremy D.

    2014-05-01

    A high-resolution assessment of health impacts from air pollution and related external cost has been conducted for Denmark using the integrated EVA model system. The EVA system has been further developed by implementing an air quality model with a 1 km x 1 km resolution covering the whole of Denmark. New developments of the integrated model system will be presented as well as results for health impacts and related external costs over several decades. Furthermore, the sensitivity of health impacts to model resolution will be studied. We have developed an integrated model system EVA (Economic Valuation of Air pollution), based on the impact-pathway chain, to assess the health impacts and health-related economic externalities of air pollution resulting from specific emission sources or sectors. The system is used to support policymaking with respect to emission control. In Brandt et al. (2013a; 2013b), the EVA system was used to assess the impacts in Europe and Denmark from the past, present and future total air pollution levels as well as the contribution from the major anthropogenic emission sectors. The EVA system was applied using the hemispheric chemistry-transport model, the Danish Eulerian Hemispheric Model (DEHM), with nesting capability for higher resolution over Europe (50 km x 50 km) and Northern Europe (16.7 km x 16.7 km). In this study an Urban Background Model (UBM) has been further developed to cover the whole of Denmark with a 1 km x 1 km resolution and the model has been implemented as a part of the integrated model system, EVA. The EVA system is based on the impact-pathway methodology. The site-specific emissions will result (via atmospheric transport and chemistry) in a concentration distribution, which together with detailed population data, are used to estimate the population-level exposure. Using exposure-response functions and economic valuations, the exposure is transformed into impacts on human health and related external costs. In this study

  4. Objective Tuning of Model Parameters in CAM5 Across Different Spatial Resolutions

    Science.gov (United States)

    Bulaevskaya, V.; Lucas, D. D.

    2014-12-01

    Parameterizations of physical processes in climate models are highly dependent on the spatial and temporal resolution and must be tuned for each resolution under consideration. At high spatial resolutions, objective methods for parameter tuning are computationally prohibitive. Our work has focused on calibrating parameters in the Community Atmosphere Model 5 (CAM5) for three spatial resolutions: 1, 2, and 4 degrees. Using perturbed-parameter ensembles and uncertainty quantification methodology, we have identified input parameters that minimize discrepancies of energy fluxes simulated by CAM5 across the three resolutions and with respect to satellite observations. We are also beginning to exploit the parameter-resolution relationships to objectively tune parameters in a high-resolution version of CAM5 by leveraging cheaper, low-resolution simulations and statistical models. We will present our approach to multi-resolution climate model parameter tuning, as well as the key findings. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 and was supported from the DOE Office of Science through the Scientific Discovery Through Advanced Computing (SciDAC) project on Multiscale Methods for Accurate, Efficient, and Scale-Aware Models of the Earth System.

  5. Assessment of prediction skill in equatorial Pacific Ocean in high resolution model of CFS

    Science.gov (United States)

    Arora, Anika; Rao, Suryachandra A.; Pillai, Prasanth; Dhakate, Ashish; Salunke, Kiran; Srivastava, Ankur

    2018-01-01

    The effect of increasing atmospheric resolution on prediction skill of El Niño southern oscillation phenomenon in climate forecast system model is explored in this paper. Improvement in prediction skill for sea surface temperature (SST) and winds at all leads compared to low resolution model in the tropical Indo-Pacific basin is observed. High resolution model is able to capture extreme events reasonably well. As a result, the signal to noise ratio is improved in the high resolution model. However, spring predictability barrier (SPB) for summer months in Nino 3 and Nino 3.4 region is stronger in high resolution model, in spite of improvement in overall prediction skill and dynamics everywhere else. Anomaly correlation coefficient of SST in high resolution model with observations in Nino 3.4 region targeting boreal summer months when predicted at lead times of 3-8 months in advance decreased compared its lower resolution counterpart. It is noted that higher variance of winds predicted in spring season over central equatorial Pacific compared to observed variance of winds results in stronger than normal response on subsurface ocean, hence increases SPB for boreal summer months in high resolution model.

  6. Ozone Production in Global Tropospheric Models: Quantifying Errors due to Grid Resolution

    Science.gov (United States)

    Wild, O.; Prather, M. J.

    2005-12-01

    Ozone production in global chemical models is dependent on model resolution because ozone chemistry is inherently nonlinear, the timescales for chemical production are short, and precursors are artificially distributed over the spatial scale of the model grid. In this study we examine the sensitivity of ozone, its precursors, and its production to resolution by running a global chemical transport model at four different resolutions between T21 (5.6° × 5.6°) and T106 (1.1° × 1.1°) and by quantifying the errors in regional and global budgets. The sensitivity to vertical mixing through the parameterization of boundary layer turbulence is also examined. We find less ozone production in the boundary layer at higher resolution, consistent with slower chemical production in polluted emission regions and greater export of precursors. Agreement with ozonesonde and aircraft measurements made during the NASA TRACE-P campaign over the Western Pacific in spring 2001 is consistently better at higher resolution. We demonstrate that the numerical errors in transport processes at a given resolution converge geometrically for a tracer at successively higher resolutions. The convergence in ozone production on progressing from T21 to T42, T63 and T106 resolution is likewise monotonic but still indicates large errors at 120~km scales, suggesting that T106 resolution is still too coarse to resolve regional ozone production. Diagnosing the ozone production and precursor transport that follow a short pulse of emissions over East Asia in springtime allows us to quantify the impacts of resolution on both regional and global ozone. Production close to continental emission regions is overestimated by 27% at T21 resolution, by 13% at T42 resolution, and by 5% at T106 resolution, but subsequent ozone production in the free troposphere is less significantly affected.

  7. Uncertainty of global summer precipitation in the CMIP5 models: a comparison between high-resolution and low-resolution models

    Science.gov (United States)

    Huang, Danqing; Yan, Peiwen; Zhu, Jian; Zhang, Yaocun; Kuang, Xueyuan; Cheng, Jing

    2018-04-01

    The uncertainty of global summer precipitation simulated by the 23 CMIP5 CGCMs and the possible impacts of model resolutions are investigated in this study. Large uncertainties exist over the tropical and subtropical regions, which can be mainly attributed to convective precipitation simulation. High-resolution models (HRMs) and low-resolution models (LRMs) are further investigated to demonstrate their different contributions to the uncertainties of the ensemble mean. It shows that the high-resolution model ensemble means (HMME) and low-resolution model ensemble mean (LMME) mitigate the biases between the MME and observation over most continents and oceans, respectively. The HMME simulates more precipitation than the LMME over most oceans, but less precipitation over some continents. The dominant precipitation category in the HRMs (LRMs) is the heavy precipitation (moderate precipitation) over the tropic regions. The combinations of convective and stratiform precipitation are also quite different: the HMME has much higher ratio of stratiform precipitation while the LMME has more convective precipitation. Finally, differences in precipitation between the HMME and LMME can be traced to their differences in the SST simulations via the local and remote air-sea interaction.

  8. Developing and measuring healthcare capacity and quality in Burundi: LifeNet International’s horizontal conversion franchise model

    Directory of Open Access Journals (Sweden)

    Michael F Brooks

    2016-01-01

    Full Text Available In a departure from traditional “vertical” healthcare interventions in low-resource settings that work to combat a single specific health issue, LifeNet International (LN uses a horizontal conversion franchise to develop and measure healthcare capacity and quality in primarily faith-based health centers in East Africa. Through a comprehensive franchise package of Medical Training, Management Training, Pharmaceutical Supply, and Growth Financing, LN is able to leverage existing resources and respond to a greater number of the obstacles preventing facilities from providing quality care. Through its Quality Score Card, LN measures improvements in quality of care within its network. This tool has measured consistent and significant improvements in quality of care following LN partnership. Together, these services improve quality of care at East African primary care facilities in ways that issue-specific, “vertical” interventions cannot.

  9. Soft-sensors: model-based estimation of inflow in horizontal wells using the extended Kalman filter

    NARCIS (Netherlands)

    Gryzlov, A.; Schiferli, W.; Mudde, R.F.

    2013-01-01

    The growing demand for hydrocarbon production has resulted in improved oilfield management using various control and optimization strategies. These strategies increasingly require downhole equipment to obtain real-time oil and gas production rates with sufficient spatial and temporal resolution. In

  10. Development and testing of a high-resolution model for tropospheric sulfate driven by observation-derived meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Benkovitz, C.M. [Brookhaven National Lab., Upton, NY (United States). Environmental Chemistry Div.

    1994-05-01

    A high-resolution three-dimensional Eulerian transport and transformation model has been developed to simulate concentrations of tropospheric sulfate for specific times and locations; it was applied over the North Atlantic and adjacent continental regions during October and November, 1986. The model represents emissions of anthropogenic SO{sub 2} and sulfate and of biogenic sulfur species, horizontal and vertical transport, gas-phase oxidation of SO{sub 2} and dimethylsulfide, aqueous-phase oxidation of SO{sub 2}, and wet and dry deposition of SO{sub 2}, sulfate, and methanesulfonic acid (MSA). The meteorological driver is the 6-hour output from the forecast model of the European Centre for Medium-Range Weather Forecasts. Calculated sulfate concentrations and column burdens, examined in detail for October 15 and October 22 at 6Z, are related to existing weather patterns. These results exhibit rich temporal and spatial structure; the characteristic (1/e) temporal autocorrelation time for the sulfate column burdens over the central North Atlantic averages 20 hours; 95% of the values were 25 hours or less. The characteristic distance of spatial autocorrelation over this region depends on direction and averages 1,600 km; with 10{sup th} percentile value of 400 km and 90{sup th} percentile value of 1,700 km. Daily average model sulfate concentrations at the lowest vertical accurately represent the spatial variability, temporal episodicity, and absolute magnitudes of surface concentrations measured by monitoring stations in Europe, Canada and Barbados.

  11. A 3D Finite Element Model with Improved Spatial Resolution to Investigate the Effect of Varying Viscosity on Antarctica

    Science.gov (United States)

    Blank, B.; van der Wal, W.; Pappa, F.; Ebbing, J.

    2017-12-01

    B. Blank1, H. Hu1, W. van der Wal1, F Pappa2, J. Ebbing21Delft University of Technology 2Christian-Albrechts-University of KielSince the beginning of the 2000's time-variable gravity data from GRACE has proved to be an effective method for mapping ice mass loss in Antarctica. However, Glacial Isostatic Adjustment (GIA) models are required to correct for GIA induced mass changes. While most GIA models have adopted an Earth model that only varies radially in parameters, it has long been clear that the Earth structure also varies with longitude and latitude. For this study a new global 3D GIA model has been developed within the finite element software package ABAQUS, which can be modified to operate on a spatial resolution down to 50 km locally. The model is being benchmarked against normal model models for surface loading. It will be used to investigate the effects of a 3D varying lithosphere and upper asthenosphere in Antarctica. Viscosity which will be computed from temperature estimates with laboratory based flow laws. A new 3D temperature map of the Antarctic lithosphere has been developed within ESA's GOCE+ project based on seismic data as well as on GOCE and GRACE inferred gravity gradients. Output from the GIA model with this new temperature estimates will be compared to that of 1D viscosity profiles and other recent 3D viscosity models based on seismic data. From these side to side comparisons we want to investigate the influence of the viscosity map on uplift rates and horizontal movement. Finally the results can be compared to GPS measurement to investigate the validity of all models.

  12. Resolution and Probabilistic Models of Components in CryoEM Maps of Mature P22 Bacteriophage

    Science.gov (United States)

    Pintilie, Grigore; Chen, Dong-Hua; Haase-Pettingell, Cameron A.; King, Jonathan A.; Chiu, Wah

    2016-01-01

    CryoEM continues to produce density maps of larger and more complex assemblies with multiple protein components of mixed symmetries. Resolution is not always uniform throughout a cryoEM map, and it can be useful to estimate the resolution in specific molecular components of a large assembly. In this study, we present procedures to 1) estimate the resolution in subcomponents by gold-standard Fourier shell correlation (FSC); 2) validate modeling procedures, particularly at medium resolutions, which can include loop modeling and flexible fitting; and 3) build probabilistic models that combine high-accuracy priors (such as crystallographic structures) with medium-resolution cryoEM densities. As an example, we apply these methods to new cryoEM maps of the mature bacteriophage P22, reconstructed without imposing icosahedral symmetry. Resolution estimates based on gold-standard FSC show the highest resolution in the coat region (7.6 Å), whereas other components are at slightly lower resolutions: portal (9.2 Å), hub (8.5 Å), tailspike (10.9 Å), and needle (10.5 Å). These differences are indicative of inherent structural heterogeneity and/or reconstruction accuracy in different subcomponents of the map. Probabilistic models for these subcomponents provide new insights, to our knowledge, and structural information when taking into account uncertainty given the limitations of the observed density. PMID:26743049

  13. Progressive refining of spatial and temporal resolutions in a hydrological model: how far should we go?

    Science.gov (United States)

    de Lavenne, Alban; Ficchi, Andrea; Goullet, Julien

    2017-04-01

    Choosing a modelling resolution for an hydrological model is an important preliminary question. However, it is quite often arbitrary determined by the modeller experience according to the objective, the model capacity or the available measurements. The hydrological literature provides numerous studies which focus on the effect of refining either spatial resolution or (sometimes) temporal resolution in order to better catch hydrological response. In this study, we investigate the impact of changing simultaneously both resolutions on hydrological model performance. The idea is that these resolutions are linked and should be considered together. Thus, we look for the combination of spatial and temporal resolutions fitting at best each catchment behaviour and type of rainfall events. A large data set of 240 catchments scattered all around France is used, and in particular, we benefit from a high-resolution precipitation database (ANTILOPE, Météo-France) that describes hourly precipitation at 1 km2 resolution. Data were aggregated at different time steps (1h, 3h, 6h, 12h and 24h). Streamflow simulations are performed at these different time steps using the GR5 model in its lumped and semi-distributed version (GRSD, de Lavenne et al. (2016)), with a mesh grid of 500, 250, 100 and 50 km2. Ten different indices are used to describe spatio-temporal characteristics of rainfall events, in order to analyse in which contexts refined resolutions are needed to improve the performance of the model. These indices characterise the spatial variability, localisation, movement, intensity and temporal variability of rainfall events. In addition to some indices already reported in the hydrological literature, we propose some new indices like an indice usually applied in economics. This analysis at different time steps, events and catchments demonstrates the limits for some of them and allows to propose some corrections (Goullet J., 2016). Model performances are shown to be

  14. Hydrologic Derivatives for Modeling and Analysis—A new global high-resolution database

    Science.gov (United States)

    Verdin, Kristine L.

    2017-07-17

    The U.S. Geological Survey has developed a new global high-resolution hydrologic derivative database. Loosely modeled on the HYDRO1k database, this new database, entitled Hydrologic Derivatives for Modeling and Analysis, provides comprehensive and consistent global coverage of topographically derived raster layers (digital elevation model data, flow direction, flow accumulation, slope, and compound topographic index) and vector layers (streams and catchment boundaries). The coverage of the data is global, and the underlying digital elevation model is a hybrid of three datasets: HydroSHEDS (Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales), GMTED2010 (Global Multi-resolution Terrain Elevation Data 2010), and the SRTM (Shuttle Radar Topography Mission). For most of the globe south of 60°N., the raster resolution of the data is 3 arc-seconds, corresponding to the resolution of the SRTM. For the areas north of 60°N., the resolution is 7.5 arc-seconds (the highest resolution of the GMTED2010 dataset) except for Greenland, where the resolution is 30 arc-seconds. The streams and catchments are attributed with Pfafstetter codes, based on a hierarchical numbering system, that carry important topological information. This database is appropriate for use in continental-scale modeling efforts. The work described in this report was conducted by the U.S. Geological Survey in cooperation with the National Aeronautics and Space Administration Goddard Space Flight Center.

  15. Nonlinear Adjustment Model with Integral and Its Application to Super Resolution Image Reconstruction

    Directory of Open Access Journals (Sweden)

    ZHU Jianjun

    2015-07-01

    Full Text Available The process of super resolution image reconstruction is such a process that multiple observations are taken on the same target to obtain low resolution images, then the low resolution images are used to reconstruct the real image of the target, namely high resolution image. This process is similar to that in the field of surveying and mapping, in which the same target is observed repeatedly and the optimal values is calculated with surveying adjustment methods. In this paper, the method of surveying adjustment is applied into super resolution image reconstruction. A integral nonlinear adjustment model for super resolution image reconstruction is proposed at first. And then the model is parameterized with a quadratic function. Finally the model is solved with the least squares adjustment method. Based on the proposed adjustment method, the specific strategy of image reconstruction is presented. This method for super resolution image reconstruction can make quantitative analysis of the results, and avoid successfully ill-condition problem, etc. The results show that, compared to the traditional method of super resolution image reconstruction, this method has greatly improved the visual effects, and the PSNR and SSIM has also greatly improved, so the method is reliable and feasible.

  16. An Assessment of the South Asian Summer Monsoon Variability for Present and Future Climatologies Using a High Resolution Regional Climate Model (RegCM4.3) under the AR5 Scenarios

    OpenAIRE

    Mujtaba Hassan; Pengfei Du; Shaofeng Jia; Waheed Iqbal; Rashid Mahmood; Wulong Ba

    2015-01-01

    We assessed the present and future climatologies of mean summer monsoon over South Asia using a high resolution regional climate model (RegCM4) with a 25 km horizontal resolution. In order to evaluate the performance of the RegCM4 for the reference period (1976–2005) and for the far future (2070–2099), climate change projections under two greenhouse gas representative concentration pathways (RCP4.5 and RCP8.5) were made, the lateral boundary conditions being provided by the geophysical fluid...

  17. A statistical prediction model based on sparse representations for single image super-resolution.

    Science.gov (United States)

    Peleg, Tomer; Elad, Michael

    2014-06-01

    We address single image super-resolution using a statistical prediction model based on sparse representations of low- and high-resolution image patches. The suggested model allows us to avoid any invariance assumption, which is a common practice in sparsity-based approaches treating this task. Prediction of high resolution patches is obtained via MMSE estimation and the resulting scheme has the useful interpretation of a feedforward neural network. To further enhance performance, we suggest data clustering and cascading several levels of the basic algorithm. We suggest a training scheme for the resulting network and demonstrate the capabilities of our algorithm, showing its advantages over existing methods based on a low- and high-resolution dictionary pair, in terms of computational complexity, numerical criteria, and visual appearance. The suggested approach offers a desirable compromise between low computational complexity and reconstruction quality, when comparing it with state-of-the-art methods for single image super-resolution.

  18. Data Driven Approach for High Resolution Population Distribution and Dynamics Models

    Energy Technology Data Exchange (ETDEWEB)

    Bhaduri, Budhendra L [ORNL; Bright, Eddie A [ORNL; Rose, Amy N [ORNL; Liu, Cheng [ORNL; Urban, Marie L [ORNL; Stewart, Robert N [ORNL

    2014-01-01

    High resolution population distribution data are vital for successfully addressing critical issues ranging from energy and socio-environmental research to public health to human security. Commonly available population data from Census is constrained both in space and time and does not capture population dynamics as functions of space and time. This imposes a significant limitation on the fidelity of event-based simulation models with sensitive space-time resolution. This paper describes ongoing development of high-resolution population distribution and dynamics models, at Oak Ridge National Laboratory, through spatial data integration and modeling with behavioral or activity-based mobility datasets for representing temporal dynamics of population. The model is resolved at 1 km resolution globally and describes the U.S. population for nighttime and daytime at 90m. Integration of such population data provides the opportunity to develop simulations and applications in critical infrastructure management from local to global scales.

  19. Relative Dispersion from a High-Resolution Coastal Model of the Adriatic Sea

    National Research Council Canada - National Science Library

    Haza, Angelique C; Poje, Andrew C; Ozgokmen, Tamay M; Martin, Paul

    2008-01-01

    Synthetic drifter trajectories computed from velocity data produced by a high-resolution NCOM model are used to investigate the scaling of relative dispersion and the distribution of finite-scale Lyapunov exponent (FSLE...

  20. Impact of precipitation spatial resolution on the hydrological response of an integrated distributed water resources model

    DEFF Research Database (Denmark)

    Fu, Suhua; Sonnenborg, Torben; Jensen, Karsten Høgh

    2011-01-01

    Precipitation is a key input variable to hydrological models, and the spatial variability of the input is expected to impact the hydrological response predicted by a distributed model. In this study, the effect of spatial resolution of precipitation on runoff , recharge and groundwater head...... was analyzed in the Alergaarde catchment in Denmark. Six different precipitation spatial resolutions were used as inputs to a physically based, distributed hydrological model, the MIKE SHE model. The results showed that the resolution of precipitation input had no apparent effect on annual water balance...... of the total catchment and runoff discharge hydrograph at watershed outlet. On the other hand, groundwater recharge and groundwater head were both aff ected. The impact of the spatial resolution of precipitation input is reduced with increasing catchment size. The effect on stream discharge is relatively low...

  1. A Toolkit for Building Hybrid, Multi-Resolution PMESII Models

    National Research Council Canada - National Science Library

    Bachman, John A; Harper, Karen A

    2007-01-01

    ...) models in support of a Commander's Predictive Environment (CPE) was developed. This development environment is based upon Charles River Analytic's Graphical Agent Development Environment (GRADE...

  2. Vertical and horizontal subsidiarity

    Directory of Open Access Journals (Sweden)

    Ivan V. Daniluk

    2016-02-01

    Full Text Available This article makes an attempt to analyze the principle of subsidiarity in its two main manifestations, namely vertical and horizontal, to outline the principles of relations between the state and regions within the vertical subsidiarity, and features a collaboration of the government and civil society within the horizontal subsidiarity. Scientists identify two types, or two levels of the subsidiarity principle: vertical subsidiarity and horizontal subsidiarity. First, vertical subsidiarity (or territorial concerning relations between the state and other levels of subnational government, such as regions and local authorities; second, horizontal subsidiarity (or functional concerns the relationship between state and citizen (and civil society. Vertical subsidiarity expressed in the context of the distribution of administrative responsibilities to the appropriate higher level lower levels relative to the state structure, ie giving more powers to local government. However, state intervention has subsidiary-lower action against local authorities in cases of insolvency last cope on their own, ie higher organisms intervene only if the duties are less authority is insufficient to achieve the goals. Horizontal subsidiarity is within the relationship between power and freedom, and is based on the assumption that the concern for the common good and the needs of common interest community, able to solve community members (as individuals and citizens’ associations and role of government, in accordance horizontal subsidiarity comes to attracting features subsidiarity assistance, programming, coordination and possibly control.

  3. A comparative verification of high resolution precipitation forecasts using model output statistics

    Science.gov (United States)

    van der Plas, Emiel; Schmeits, Maurice; Hooijman, Nicolien; Kok, Kees

    2017-04-01

    Verification of localized events such as precipitation has become even more challenging with the advent of high-resolution meso-scale numerical weather prediction (NWP). The realism of a forecast suggests that it should compare well against precipitation radar imagery with similar resolution, both spatially and temporally. Spatial verification methods solve some of the representativity issues that point verification gives rise to. In this study a verification strategy based on model output statistics is applied that aims to address both double penalty and resolution effects that are inherent to comparisons of NWP models with different resolutions. Using predictors based on spatial precipitation patterns around a set of stations, an extended logistic regression (ELR) equation is deduced, leading to a probability forecast distribution of precipitation for each NWP model, analysis and lead time. The ELR equations are derived for predictands based on areal calibrated radar precipitation and SYNOP observations. The aim is to extract maximum information from a series of precipitation forecasts, like a trained forecaster would. The method is applied to the non-hydrostatic model Harmonie (2.5 km resolution), Hirlam (11 km resolution) and the ECMWF model (16 km resolution), overall yielding similar Brier skill scores for the 3 post-processed models, but larger differences for individual lead times. Besides, the Fractions Skill Score is computed using the 3 deterministic forecasts, showing somewhat better skill for the Harmonie model. In other words, despite the realism of Harmonie precipitation forecasts, they only perform similarly or somewhat better than precipitation forecasts from the 2 lower resolution models, at least in the Netherlands.

  4. Automatic Detection and Resolution of Lexical Ambiguity in Process Models

    NARCIS (Netherlands)

    Pittke, F.; Leopold, H.; Mendling, J.

    2015-01-01

    System-related engineering tasks are often conducted using process models. In this context, it is essential that these models do not contain structural or terminological inconsistencies. To this end, several automatic analysis techniques have been proposed to support quality assurance. While formal

  5. A Toolkit for Building Hybrid, Multi-Resolution PMESII Models

    Science.gov (United States)

    2007-11-01

    Ptolemy Integration 23 4. Support for Interoperable PMESII Modeling 31 5. Support for PMESII Model Verification and Validation 34 5.1 Verification 34...terrorist leader behavior .............................................. 20 Figure 3-2: Editors for Two Ptolemy Components in the GRADE Edit Workspace...27 Figure 3-3: Selecting the Customize→Ports Context Menu Item in the Ptolemy Component Editor

  6. A new timing model for calculating the intrinsic timing resolution of a scintillator detector

    International Nuclear Information System (INIS)

    Shao Yiping

    2007-01-01

    The coincidence timing resolution is a critical parameter which to a large extent determines the system performance of positron emission tomography (PET). This is particularly true for time-of-flight (TOF) PET that requires an excellent coincidence timing resolution (<<1 ns) in order to significantly improve the image quality. The intrinsic timing resolution is conventionally calculated with a single-exponential timing model that includes two parameters of a scintillator detector: scintillation decay time and total photoelectron yield from the photon-electron conversion. However, this calculation has led to significant errors when the coincidence timing resolution reaches 1 ns or less. In this paper, a bi-exponential timing model is derived and evaluated. The new timing model includes an additional parameter of a scintillator detector: scintillation rise time. The effect of rise time on the timing resolution has been investigated analytically, and the results reveal that the rise time can significantly change the timing resolution of fast scintillators that have short decay time constants. Compared with measured data, the calculations have shown that the new timing model significantly improves the accuracy in the calculation of timing resolutions

  7. Toward an ultra-high resolution community climate system model for the BlueGene platform

    International Nuclear Information System (INIS)

    Dennis, John M; Jacob, Robert; Vertenstein, Mariana; Craig, Tony; Loy, Raymond

    2007-01-01

    Global climate models need to simulate several small, regional-scale processes which affect the global circulation in order to accurately simulate the climate. This is particularly important in the ocean where small scale features such as oceanic eddies are currently represented with adhoc parameterizations. There is also a need for higher resolution to provide climate predictions at small, regional scales. New high-performance computing platforms such as the IBM BlueGene can provide the necessary computational power to perform ultra-high resolution climate model integrations. We have begun to investigate the scaling of the individual components of the Community Climate System Model to prepare it for integrations on BlueGene and similar platforms. Our investigations show that it is possible to successfully utilize O(32K) processors. We describe the scalability of five models: the Parallel Ocean Program (POP), the Community Ice CodE (CICE), the Community Land Model (CLM), and the new CCSM sequential coupler (CPL7) which are components of the next generation Community Climate System Model (CCSM); as well as the High-Order Method Modeling Environment (HOMME) which is a dynamical core currently being evaluated within the Community Atmospheric Model. For our studies we concentrate on 1/10 0 resolution for CICE, POP, and CLM models and 1/4 0 resolution for HOMME. The ability to simulate high resolutions on the massively parallel petascale systems that will dominate high-performance computing for the foreseeable future is essential to the advancement of climate science

  8. Investigating the Effects of Grid Resolution of WRF Model for Simulating the Atmosphere for use in the Study of Wake Turbulence

    Science.gov (United States)

    Prince, Alyssa; Trout, Joseph; di Mercurio, Alexis

    2017-01-01

    The Weather Research and Forecasting (WRF) Model is a nested-grid, mesoscale numerical weather prediction system maintained by the Developmental Testbed Center. The model simulates the atmosphere by integrating partial differential equations, which use the conservation of horizontal momentum, conservation of thermal energy, and conservation of mass along with the ideal gas law. This research investigated the possible use of WRF in investigating the effects of weather on wing tip wake turbulence. This poster shows the results of an investigation into the accuracy of WRF using different grid resolutions. Several atmospheric conditions were modeled using different grid resolutions. In general, the higher the grid resolution, the better the simulation, but the longer the model run time. This research was supported by Dr. Manuel A. Rios, Ph.D. (FAA) and the grant ``A Pilot Project to Investigate Wake Vortex Patterns and Weather Patterns at the Atlantic City Airport by the Richard Stockton College of NJ and the FAA'' (13-G-006). Dr. Manuel A. Rios, Ph.D. (FAA), and the grant ``A Pilot Project to Investigate Wake Vortex Patterns and Weather Patterns at the Atlantic City Airport by the Richard Stockton College of NJ and the FAA''

  9. The Winfrith horizontal impact rig

    International Nuclear Information System (INIS)

    Barr, P.

    1985-12-01

    The Horizontal Impact Rig has been designed to allow studies of the impact of radioactive material transport containers and their associated transport vehicles and impact limiters, using large scale models, and to allow physically large missiles to be projected for studying the impact behaviour of metal and concrete structures. It provides an adequately rigid support structure for impact experiments with targets of large dimensions. Details of its design, instrumentation, performance prediction and construction are given. (U.K.)

  10. Modelling of a single-component two-phase flow regime map in a horizontal pipe with rod bundles

    International Nuclear Information System (INIS)

    Busono, P.; Chang, J.S.; Krishnan, V.S.

    2004-01-01

    Many flow regime maps in current use for modelling two-phase flow with rod bundles were developed for adiabatic situations and without interface mass transfer being taken into account. This paper describes the development of a flow regime map which includes the modelling the mass transfer between the two phases. The model used is a modified form of the mechanistic model proposed by Osamusali and Chang. The effect of interfacial mass transfer on flow regime transitions predicted by the new model is discussed in detail in this paper. (author)

  11. A regional high resolution model of the marine mercury cycle.

    Science.gov (United States)

    Bieser, J.; Daewel, U.; Schrum, C.

    2017-12-01

    One of the main sources for mercury intoxication is the uptake of methylmercury from sea food. However, only little is known about the dynamics of methylmercury in the marine environment and its accumulation along the food chain. To further our understanding of the pathways from anthropogenic emissions of elemental mercury to the bio-accumulation of methylmercury in fish we developed the first regional Eulerian three dimensional multi-media chemistry transport model (MECOSMO) that includes atmosphere, ocean, and ecosystem. The marine part of the model includes a complete representation of the marine ecosystem ranging from phytoplankton up to higher trophic levels, including fish. We used the MECOSMO model to reconstruct mercury concentrations in water and biota in the North- and Baltic Sea for the past 60 years. Based on our model we examined the natural short and longterm variability of the system as well as long term trends in the distribution and amount of methylmercury in water and fish. Based on our findings we show how models can be utilized to develop future measurement strategies for marine mercury. Finally, the presented modelling system can be used to project the impact of future perturbations in the system (i.e.: emission reductions, climate change, nutrient control) on the mercury accumulation in sea food. Thereby, supporting the implementation of the Minamata Convention on Mercury on a regional scale by enabling us to estimate the impact of emission reductions on the marine mercury cycle.

  12. Reducing uncertainty in high-resolution sea ice models.

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Kara J.; Bochev, Pavel Blagoveston

    2013-07-01

    Arctic sea ice is an important component of the global climate system, reflecting a significant amount of solar radiation, insulating the ocean from the atmosphere and influencing ocean circulation by modifying the salinity of the upper ocean. The thickness and extent of Arctic sea ice have shown a significant decline in recent decades with implications for global climate as well as regional geopolitics. Increasing interest in exploration as well as climate feedback effects make predictive mathematical modeling of sea ice a task of tremendous practical import. Satellite data obtained over the last few decades have provided a wealth of information on sea ice motion and deformation. The data clearly show that ice deformation is focused along narrow linear features and this type of deformation is not well-represented in existing models. To improve sea ice dynamics we have incorporated an anisotropic rheology into the Los Alamos National Laboratory global sea ice model, CICE. Sensitivity analyses were performed using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA) to determine the impact of material parameters on sea ice response functions. Two material strength parameters that exhibited the most significant impact on responses were further analyzed to evaluate their influence on quantitative comparisons between model output and data. The sensitivity analysis along with ten year model runs indicate that while the anisotropic rheology provides some benefit in velocity predictions, additional improvements are required to make this material model a viable alternative for global sea ice simulations.

  13. Impact of rainfall temporal resolution on urban water quality modelling performance and uncertainties.

    Science.gov (United States)

    Manz, Bastian Johann; Rodríguez, Juan Pablo; Maksimović, Cedo; McIntyre, Neil

    2013-01-01

    A key control on the response of an urban drainage model is how well the observed rainfall records represent the real rainfall variability. Particularly in urban catchments with fast response flow regimes, the selection of temporal resolution in rainfall data collection is critical. Furthermore, the impact of the rainfall variability on the model response is amplified for water quality estimates, as uncertainty in rainfall intensity affects both the rainfall-runoff and pollutant wash-off sub-models, thus compounding uncertainties. A modelling study was designed to investigate the impact of altering rainfall temporal resolution on the magnitude and behaviour of uncertainties associated with the hydrological modelling compared with water quality modelling. The case study was an 85-ha combined sewer sub-catchment in Bogotá (Colombia). Water quality estimates showed greater sensitivity to the inter-event variability in rainfall hyetograph characteristics than to changes in the rainfall input temporal resolution. Overall, uncertainties from the water quality model were two- to five-fold those of the hydrological model. However, owing to the intrinsic scarcity of observations in urban water quality modelling, total model output uncertainties, especially from the water quality model, were too large to make recommendations for particular model structures or parameter values with respect to rainfall temporal resolution.

  14. The application of high temporal resolution data in river catchment modelling and management strategies.

    Science.gov (United States)

    Crockford, L; O'Riordain, S; Taylor, D; Melland, A R; Shortle, G; Jordan, P

    2017-08-21

    Modelling changes in river water quality, and by extension developing river management strategies, has historically been reliant on empirical data collected at relatively low temporal resolutions. With access to data collected at higher temporal resolutions, this study investigated how these new dataset types could be employed to assess the precision and accuracy of two phosphorus (P) load apportionment models (LAMs) developed on lower resolution empirical data. Predictions were made of point and diffuse sources of P across ten different sampling scenarios. Sampling resolution ranged from hourly to monthly through the use of 2000 newly created datasets from high frequency P and discharge data collected from a eutrophic river draining a 9.48 km 2 catchment. Outputs from the two LAMs were found to differ significantly in the P load apportionment (51.4% versus 4.6% from point sources) with reducing precision and increasing bias as sampling frequency decreased. Residual analysis identified a large deviation from observed data at high flows. This deviation affected the apportionment of P from diffuse sources in particular. The study demonstrated the potential problems in developing empirical models such as LAMs based on temporally relatively poorly-resolved data (the level of resolution that is available for the majority of catchments). When these models are applied ad hoc and outside an expert modelling framework using extant datasets of lower resolution, interpretations of their outputs could potentially reduce the effectiveness of management decisions aimed at improving water quality.

  15. Addressing capability computing challenges of high-resolution global climate modelling at the Oak Ridge Leadership Computing Facility

    Science.gov (United States)

    Anantharaj, Valentine; Norman, Matthew; Evans, Katherine; Taylor, Mark; Worley, Patrick; Hack, James; Mayer, Benjamin

    2014-05-01

    During 2013, high-resolution climate model simulations accounted for over 100 million "core hours" using Titan at the Oak Ridge Leadership Computing Facility (OLCF). The suite of climate modeling experiments, primarily using the Community Earth System Model (CESM) at nearly 0.25 degree horizontal resolution, generated over a petabyte of data and nearly 100,000 files, ranging in sizes from 20 MB to over 100 GB. Effective utilization of leadership class resources requires careful planning and preparation. The application software, such as CESM, need to be ported, optimized and benchmarked for the target platform in order to meet the computational readiness requirements. The model configuration needs to be "tuned and balanced" for the experiments. This can be a complicated and resource intensive process, especially for high-resolution configurations using complex physics. The volume of I/O also increases with resolution; and new strategies may be required to manage I/O especially for large checkpoint and restart files that may require more frequent output for resiliency. It is also essential to monitor the application performance during the course of the simulation exercises. Finally, the large volume of data needs to be analyzed to derive the scientific results; and appropriate data and information delivered to the stakeholders. Titan is currently the largest supercomputer available for open science. The computational resources, in terms of "titan core hours" are allocated primarily via the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) and ASCR Leadership Computing Challenge (ALCC) programs, both sponsored by the U.S. Department of Energy (DOE) Office of Science. Titan is a Cray XK7 system, capable of a theoretical peak performance of over 27 PFlop/s, consists of 18,688 compute nodes, with a NVIDIA Kepler K20 GPU and a 16-core AMD Opteron CPU in every node, for a total of 299,008 Opteron cores and 18,688 GPUs offering a cumulative 560

  16. A new high resolution tidal model in the arctic ocean

    DEFF Research Database (Denmark)

    Cancet, M.; Andersen, Ole Baltazar; Lyard, F.

    The Arctic Ocean is a challenging region for tidal modeling, because of its complex and not well-documented bathymetry, together combined with the intermittent presence of sea ice and the fact that the in situ tidal observations are rather scarce at such high latitudes. As a consequence......, the accuracy of the global tidal models decreases by several centimeters in the Polar Regions. In particular, it has a large impact on the quality of the satellite altimeter sea surface heights in these regions (ERS1/2, Envisat, CryoSat-2, SARAL/AltiKa and the future Sentinel-3 mission). Better knowledge...... of the tides improves the quality of the high latitudes altimeter sea surface heights and of all derived products, such as the altimetry-derived geostrophic currents, the mean sea surface and the mean dynamic topography. In addition, accurate tidal models are highly strategic information for ever...

  17. Quantitative Research: A Dispute Resolution Model for FTC Advertising Regulation.

    Science.gov (United States)

    Richards, Jef I.; Preston, Ivan L.

    Noting the lack of a dispute mechanism for determining whether an advertising practice is truly deceptive without generating the costs and negative publicity produced by traditional Federal Trade Commission (FTC) procedures, this paper proposes a model based upon early termination of the issues through jointly commissioned behavioral research. The…

  18. High Resolution PV Power Modeling for Distribution Circuit Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Norris, B. L.; Dise, J. H.

    2013-09-01

    NREL has contracted with Clean Power Research to provide 1-minute simulation datasets of PV systems located at three high penetration distribution feeders in the service territory of Southern California Edison (SCE): Porterville, Palmdale, and Fontana, California. The resulting PV simulations will be used to separately model the electrical circuits to determine the impacts of PV on circuit operations.

  19. Numerical resolution of a model of tumour growth.

    Science.gov (United States)

    Muñoz, Ana I

    2016-03-01

    We consider and solve numerically a mathematical model of tumour growth based on cancer stem cells (CSC) hypothesis with the aim of gaining some insight into the relation of different processes leading to exponential growth in solid tumours and into the evolution of different subpopulations of cells. The model consists of four hyperbolic equations of first order to describe the evolution of four subpopulations of cells. A fifth equation is introduced to model the evolution of the moving boundary. The coefficients of the model represent the rates at which reactions occur. In order to integrate numerically the four hyperbolic equations, a formulation in terms of the total derivatives is posed. A finite element discretization is applied to integrate the model equations in space. Our numerical results suggest the existence of a pseudo-equilibrium state reached at the early stage of the tumour, for which the fraction of CSC remains small. We include the study of the behaviour of the solutions for longer times and we obtain that the solutions to the system of partial differential equations stabilize to homogeneous steady states whose values depend only on the values of the parameters. We show that CSC may comprise different proportions of the tumour, becoming, in some cases, the predominant type of cells within the tumour. We also obtain that possible effective measure to detain tumour progression should combine the targeting of CSC with the targeting of progenitor cells. © The Authors 2015. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  20. Utilization of Short-Simulations for Tuning High-Resolution Climate Model

    Science.gov (United States)

    Lin, W.; Xie, S.; Ma, P. L.; Rasch, P. J.; Qian, Y.; Wan, H.; Ma, H. Y.; Klein, S. A.

    2016-12-01

    Many physical parameterizations in atmospheric models are sensitive to resolution. Tuning the models that involve a multitude of parameters at high resolution is computationally expensive, particularly when relying primarily on multi-year simulations. This work describes a complementary set of strategies for tuning high-resolution atmospheric models, using ensembles of short simulations to reduce the computational cost and elapsed time. Specifically, we utilize the hindcast approach developed through the DOE Cloud Associated Parameterization Testbed (CAPT) project for high-resolution model tuning, which is guided by a combination of short (global mean statistics and many spatial features are consistent between Atmospheric Model Intercomparison Project (AMIP)-type simulations and CAPT-type hindcasts, with just a small number of short-term simulations for the latter over the corresponding season. The use of CAPT hindcasts to find parameter choice for the reduction of large model biases dramatically improves the turnaround time for the tuning at high resolution. Improvement seen in CAPT hindcasts generally translates to improved AMIP-type simulations. An iterative CAPT-AMIP tuning approach is therefore adopted during each major tuning cycle, with the former to survey the likely responses and narrow the parameter space, and the latter to verify the results in climate context along with assessment in greater detail once an educated set of parameter choice is selected. Limitations on using short-term simulations for tuning climate model are also discussed.

  1. The implementation of sea ice model on a regional high-resolution scale

    Science.gov (United States)

    Prasad, Siva; Zakharov, Igor; Bobby, Pradeep; McGuire, Peter

    2015-09-01

    The availability of high-resolution atmospheric/ocean forecast models, satellite data and access to high-performance computing clusters have provided capability to build high-resolution models for regional ice condition simulation. The paper describes the implementation of the Los Alamos sea ice model (CICE) on a regional scale at high resolution. The advantage of the model is its ability to include oceanographic parameters (e.g., currents) to provide accurate results. The sea ice simulation was performed over Baffin Bay and the Labrador Sea to retrieve important parameters such as ice concentration, thickness, ridging, and drift. Two different forcing models, one with low resolution and another with a high resolution, were used for the estimation of sensitivity of model results. Sea ice behavior over 7 years was simulated to analyze ice formation, melting, and conditions in the region. Validation was based on comparing model results with remote sensing data. The simulated ice concentration correlated well with Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and Ocean and Sea Ice Satellite Application Facility (OSI-SAF) data. Visual comparison of ice thickness trends estimated from the Soil Moisture and Ocean Salinity satellite (SMOS) agreed with the simulation for year 2010-2011.

  2. Lagrangian Timescales of Southern Ocean Upwelling in a Hierarchy of Model Resolutions

    Science.gov (United States)

    Drake, Henri F.; Morrison, Adele K.; Griffies, Stephen M.; Sarmiento, Jorge L.; Weijer, Wilbert; Gray, Alison R.

    2018-01-01

    In this paper we study upwelling pathways and timescales of Circumpolar Deep Water (CDW) in a hierarchy of models using a Lagrangian particle tracking method. Lagrangian timescales of CDW upwelling decrease from 87 years to 31 years to 17 years as the ocean resolution is refined from 1° to 0.25° to 0.1°. We attribute some of the differences in timescale to the strength of the eddy fields, as demonstrated by temporally degrading high-resolution model velocity fields. Consistent with the timescale dependence, we find that an average Lagrangian particle completes 3.2 circumpolar loops in the 1° model in comparison to 0.9 loops in the 0.1° model. These differences suggest that advective timescales and thus interbasin merging of upwelling CDW may be overestimated by coarse-resolution models, potentially affecting the skill of centennial scale climate change projections.

  3. Development of fine-resolution analyses and expanded large-scale forcing properties: 2. Scale awareness and application to single-column model experiments

    Science.gov (United States)

    Feng, Sha; Li, Zhijin; Liu, Yangang; Lin, Wuyin; Zhang, Minghua; Toto, Tami; Vogelmann, Andrew M.; Endo, Satoshi

    2015-01-01

    three-dimensional fields have been produced using the Community Gridpoint Statistical Interpolation (GSI) data assimilation system for the U.S. Department of Energy's Atmospheric Radiation Measurement Program (ARM) Southern Great Plains region. The GSI system is implemented in a multiscale data assimilation framework using the Weather Research and Forecasting model at a cloud-resolving resolution of 2 km. From the fine-resolution three-dimensional fields, large-scale forcing is derived explicitly at grid-scale resolution; a subgrid-scale dynamic component is derived separately, representing subgrid-scale horizontal dynamic processes. Analyses show that the subgrid-scale dynamic component is often a major component over the large-scale forcing for grid scales larger than 200 km. The single-column model (SCM) of the Community Atmospheric Model version 5 is used to examine the impact of the grid-scale and subgrid-scale dynamic components on simulated precipitation and cloud fields associated with a mesoscale convective system. It is found that grid-scale size impacts simulated precipitation, resulting in an overestimation for grid scales of about 200 km but an underestimation for smaller grids. The subgrid-scale dynamic component has an appreciable impact on the simulations, suggesting that grid-scale and subgrid-scale dynamic components should be considered in the interpretation of SCM simulations.

  4. Core surface flow modelling from high-resolution secular variation

    DEFF Research Database (Denmark)

    Holme, R.; Olsen, Nils

    2006-01-01

    -flux hypothesis, but the spectrum of the SV implies that a conclusive test of frozen-flux is not possible. We parametrize the effects of diffusion as an expected misfit in the flow prediction due to departure from the frozen-flux hypothesis; at low spherical harmonic degrees, this contribution dominates...... the expected departure of the SV predictions from flow to the observed SV, while at high degrees the SV model uncertainty is dominant. We construct fine-scale core surface flows to model the SV. Flow non-uniqueness is a serious problem because the flows are sufficiently small scale to allow flow around non......-series of magnetic data and better parametrization of the external magnetic field....

  5. Data Integration for the Generation of High Resolution Reservoir Models

    Energy Technology Data Exchange (ETDEWEB)

    Albert Reynolds; Dean Oliver; Gaoming Li; Yong Zhao; Chaohui Che; Kai Zhang; Yannong Dong; Chinedu Abgalaka; Mei Han

    2009-01-07

    The goal of this three-year project was to develop a theoretical basis and practical technology for the integration of geologic, production and time-lapse seismic data in a way that makes best use of the information for reservoir description and reservoir performance predictions. The methodology and practical tools for data integration that were developed in this research project have been incorporated into computational algorithms that are feasible for large scale reservoir simulation models. As the integration of production and seismic data require calibrating geological/geostatistical models to these data sets, the main computational tool is an automatic history matching algorithm. The following specific goals were accomplished during this research. (1) We developed algorithms for calibrating the location of the boundaries of geologic facies and the distribution of rock properties so that production and time-lapse seismic data are honored. (2) We developed and implemented specific procedures for conditioning reservoir models to time-lapse seismic data. (3) We developed and implemented algorithms for the characterization of measurement errors which are needed to determine the relative weights of data when conditioning reservoir models to production and time-lapse seismic data by automatic history matching. (4) We developed and implemented algorithms for the adjustment of relative permeability curves during the history matching process. (5) We developed algorithms for production optimization which accounts for geological uncertainty within the context of closed-loop reservoir management. (6) To ensure the research results will lead to practical public tools for independent oil companies, as part of the project we built a graphical user interface for the reservoir simulator and history matching software using Visual Basic.

  6. Uncertainty of SWAT model at different DEM resolutions in a large mountainous watershed.

    Science.gov (United States)

    Zhang, Peipei; Liu, Ruimin; Bao, Yimeng; Wang, Jiawei; Yu, Wenwen; Shen, Zhenyao

    2014-04-15

    The objective of this study was to enhance understanding of the sensitivity of the SWAT model to the resolutions of Digital Elevation Models (DEMs) based on the analysis of multiple evaluation indicators. The Xiangxi River, a large tributary of Three Gorges Reservoir in China, was selected as the study area. A range of 17 DEM spatial resolutions, from 30 to 1000 m, was examined, and the annual and monthly model outputs based on each resolution were compared. The following results were obtained: (i) sediment yield was greatly affected by DEM resolution; (ii) the prediction of dissolved oxygen load was significantly affected by DEM resolutions coarser than 500 m; (iii) Total Nitrogen (TN) load was not greatly affected by the DEM resolution; (iv) Nitrate Nitrogen (NO₃-N) and Total Phosphorus (TP) loads were slightly affected by the DEM resolution; and (v) flow and Ammonia Nitrogen (NH₄-N) load were essentially unaffected by the DEM resolution. The flow and dissolved oxygen load decreased more significantly in the dry season than in the wet and normal seasons. Excluding flow and dissolved oxygen, the uncertainties of the other Hydrology/Non-point Source (H/NPS) pollution indicators were greater in the wet season than in the dry and normal seasons. Considering the temporal distribution uncertainties, the optimal DEM resolutions for flow was 30-200 m, for sediment and TP was 30-100 m, for dissolved oxygen and NO₃-N was 30-300 m, for NH₄-N was 30 to 70 m and for TN was 30-150 m. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Assessment of Land Surface Models in a High-Resolution Atmospheric Model during Indian Summer Monsoon

    Science.gov (United States)

    Attada, Raju; Kumar, Prashant; Dasari, Hari Prasad

    2018-04-01

    Assessment of the land surface models (LSMs) on monsoon studies over the Indian summer monsoon (ISM) region is essential. In this study, we evaluate the skill of LSMs at 10 km spatial resolution in simulating the 2010 monsoon season. The thermal diffusion scheme (TDS), rapid update cycle (RUC), and Noah and Noah with multi-parameterization (Noah-MP) LSMs are chosen based on nature of complexity, that is, from simple slab model to multi-parameterization options coupled with the Weather Research and Forecasting (WRF) model. Model results are compared with the available in situ observations and reanalysis fields. The sensitivity of monsoon elements, surface characteristics, and vertical structures to different LSMs is discussed. Our results reveal that the monsoon features are reproduced by WRF model with all LSMs, but with some regional discrepancies. The model simulations with selected LSMs are able to reproduce the broad rainfall patterns, orography-induced rainfall over the Himalayan region, and dry zone over the southern tip of India. The unrealistic precipitation pattern over the equatorial western Indian Ocean is simulated by WRF-LSM-based experiments. The spatial and temporal distributions of top 2-m soil characteristics (soil temperature and soil moisture) are well represented in RUC and Noah-MP LSM-based experiments during the ISM. Results show that the WRF simulations with RUC, Noah, and Noah-MP LSM-based experiments significantly improved the skill of 2-m temperature and moisture compared to TDS (chosen as a base) LSM-based experiments. Furthermore, the simulations with Noah, RUC, and Noah-MP LSMs exhibit minimum error in thermodynamics fields. In case of surface wind speed, TDS LSM performed better compared to other LSM experiments. A significant improvement is noticeable in simulating rainfall by WRF model with Noah, RUC, and Noah-MP LSMs over TDS LSM. Thus, this study emphasis the importance of choosing/improving LSMs for simulating the ISM phenomena in

  8. Assessment of Land Surface Models in a High-Resolution Atmospheric Model during Indian Summer Monsoon

    KAUST Repository

    Attada, Raju

    2018-04-17

    Assessment of the land surface models (LSMs) on monsoon studies over the Indian summer monsoon (ISM) region is essential. In this study, we evaluate the skill of LSMs at 10 km spatial resolution in simulating the 2010 monsoon season. The thermal diffusion scheme (TDS), rapid update cycle (RUC), and Noah and Noah with multi-parameterization (Noah-MP) LSMs are chosen based on nature of complexity, that is, from simple slab model to multi-parameterization options coupled with the Weather Research and Forecasting (WRF) model. Model results are compared with the available in situ observations and reanalysis fields. The sensitivity of monsoon elements, surface characteristics, and vertical structures to different LSMs is discussed. Our results reveal that the monsoon features are reproduced by WRF model with all LSMs, but with some regional discrepancies. The model simulations with selected LSMs are able to reproduce the broad rainfall patterns, orography-induced rainfall over the Himalayan region, and dry zone over the southern tip of India. The unrealistic precipitation pattern over the equatorial western Indian Ocean is simulated by WRF–LSM-based experiments. The spatial and temporal distributions of top 2-m soil characteristics (soil temperature and soil moisture) are well represented in RUC and Noah-MP LSM-based experiments during the ISM. Results show that the WRF simulations with RUC, Noah, and Noah-MP LSM-based experiments significantly improved the skill of 2-m temperature and moisture compared to TDS (chosen as a base) LSM-based experiments. Furthermore, the simulations with Noah, RUC, and Noah-MP LSMs exhibit minimum error in thermodynamics fields. In case of surface wind speed, TDS LSM performed better compared to other LSM experiments. A significant improvement is noticeable in simulating rainfall by WRF model with Noah, RUC, and Noah-MP LSMs over TDS LSM. Thus, this study emphasis the importance of choosing/improving LSMs for simulating the ISM phenomena

  9. Using Molecular Simulation to Model High-Resolution Cryo-EM Reconstructions.

    Science.gov (United States)

    Kirmizialtin, Serdal; Loerke, Justus; Behrmann, Elmar; Spahn, Christian M T; Sanbonmatsu, Karissa Y

    2015-01-01

    An explosion of new data from high-resolution cryo-electron microscopy (cryo-EM) studies has produced a large number of data sets for many species of ribosomes in various functional states over the past few years. While many methods exist to produce structural models for lower resolution cryo-EM reconstructions, high-resolution reconstructions are often modeled using crystallographic techniques and extensive manual intervention. Here, we present an automated fitting technique for high-resolution cryo-EM data sets that produces all-atom models highly consistent with the EM density. Using a molecular dynamics approach, atomic positions are optimized with a potential that includes the cross-correlation coefficient between the structural model and the cryo-EM electron density, as well as a biasing potential preserving the stereochemistry and secondary structure of the biomolecule. Specifically, we use a hybrid structure-based/ab initio molecular dynamics potential to extend molecular dynamics fitting. In addition, we find that simulated annealing integration, as opposed to straightforward molecular dynamics integration, significantly improves performance. We obtain atomistic models of the human ribosome consistent with high-resolution cryo-EM reconstructions of the human ribosome. Automated methods such as these have the potential to produce atomistic models for a large number of ribosome complexes simultaneously that can be subsequently refined manually. © 2015 Elsevier Inc. All rights reserved.

  10. Submesoscale features and their interaction with fronts and internal tides in a high-resolution coupled atmosphere-ocean-wave model of the Bay of Bengal

    Science.gov (United States)

    Jensen, Tommy G.; Shulman, Igor; Wijesekera, Hemantha W.; Anderson, Stephanie; Ladner, Sherwin

    2018-03-01

    Large freshwater fluxes into the Bay of Bengal by rainfall and river discharges result in strong salinity fronts in the bay. In this study, a high-resolution coupled atmosphere-ocean-wave model with comprehensive physics is used to model the weather, ocean circulation, and wave field in the Bay of Bengal. Our objective is to explore the submesoscale activity that occurs in a realistic coupled model that resolves mesoscales and allows part of the submesoscale field. Horizontal resolution in the atmosphere varies from 2 to 6 km and is 13 km for surface waves, while the ocean model is submesoscale permitting with resolutions as high as 1.5 km and a vertical resolution of 0.5 m in the upper 10 m. In this paper, three different cases of oceanic submesoscale features are discussed. In the first case, heavy rainfall and intense downdrafts produced by atmospheric convection are found to force submesoscale currents, temperature, and salinity anomalies in the oceanic mixed layer and impact the mesoscale flow. In a second case, strong solitary-like waves are generated by semidiurnal tides in the Andaman Sea and interact with mesoscale flows and fronts and affect submesoscale features generated along fronts. A third source of submesoscale variability is found further north in the Bay of Bengal where river outflows help maintain strong salinity gradients throughout the year. For that case, a comparison with satellite observations of sea surface height anomalies, sea surface temperature, and chlorophyll shows that the model captures the observed mesoscale eddy features of the flow field, but in addition, submesoscale upwelling and downwelling patterns associated with ageostrophic secondary circulations along density fronts are also captured by the model.

  11. The ICE-6G_C (VM5a) Global Model of the GIA Process: Antarctica at High Spatial Resolution

    Science.gov (United States)

    Peltier, W. R.; Drummond, R.; Argus, D. F.

    2016-12-01

    The ICE-6G_C (VM5a) global model of the glacial isostatic adjustment process (Argus et al., 2014 GJI 198, 537-563; Peltier et al. , 2015, JGR 119, doi:10.1002/2014JB011176) is the latest model in the ICE-nG (VMx) sequence. The model continues to be unique in that it is the only model whose properties are made freely available at each iterative step in its development. This latest version, which embodies detailed descriptions of the Laurentide , Fennoscandian/Barents Sea, Greenland and Antarctic ice sheets through the most recent glacial cycle, is a refinement based primarily upon the incorporation of the constraints being provided by GPS measurements of the vertical and horizontal motion of the crust as well as GRACE observations of the time dependent gravity field. The model has been shown to provide exceptionally accurate predictions of these space geodetic observations of the response to the most recent Late Quaternary glacial cycle. Particular attention has been paid to the Antarctic component as it is well known on the basis of analyses of the sedimentary stratigraphy off-shore and geomorphological characteristics of the continental shelf, that the Last Glacial Maximum state of the southern continent was one in which grounded ice extended out to the shelf break in most locations, including significant fractions of the Ross Sea and Weddell Sea embayments. In the latter regions especially, it is expected that grounded ice would have existed below sea level. In ICE-6G_C (VM5a) a grounding line tracking algorithm was employed (Stuhne and Peltier, 2015 JGR 120, 1841-1865) in order to describe the unloading of the solid surface by ice that was initially grounded below sea level, an apparently unique characteristic of this model. In the initially published version, in which the Sea Level Equation (SLE) was inverted on a basis of spherical harmonics truncated at degree and order 256, this led to "ringing" in the embayments when the Stokes coefficients of the model

  12. The effects of digital elevation model resolution on the calculation and predictions of topographic wetness indices.

    Energy Technology Data Exchange (ETDEWEB)

    Drover, Damion, Ryan

    2011-12-01

    One of the largest exports in the Southeast U.S. is forest products. Interest in biofuels using forest biomass has increased recently, leading to more research into better forest management BMPs. The USDA Forest Service, along with the Oak Ridge National Laboratory, University of Georgia and Oregon State University are researching the impacts of intensive forest management for biofuels on water quality and quantity at the Savannah River Site in South Carolina. Surface runoff of saturated areas, transporting excess nutrients and contaminants, is a potential water quality issue under investigation. Detailed maps of variable source areas and soil characteristics would therefore be helpful prior to treatment. The availability of remotely sensed and computed digital elevation models (DEMs) and spatial analysis tools make it easy to calculate terrain attributes. These terrain attributes can be used in models to predict saturated areas or other attributes in the landscape. With laser altimetry, an area can be flown to produce very high resolution data, and the resulting data can be resampled into any resolution of DEM desired. Additionally, there exist many maps that are in various resolutions of DEM, such as those acquired from the U.S. Geological Survey. Problems arise when using maps derived from different resolution DEMs. For example, saturated areas can be under or overestimated depending on the resolution used. The purpose of this study was to examine the effects of DEM resolution on the calculation of topographic wetness indices used to predict variable source areas of saturation, and to find the best resolutions to produce prediction maps of soil attributes like nitrogen, carbon, bulk density and soil texture for low-relief, humid-temperate forested hillslopes. Topographic wetness indices were calculated based on the derived terrain attributes, slope and specific catchment area, from five different DEM resolutions. The DEMs were resampled from LiDAR, which is a

  13. Topogrid Derived 10 Meter Resolution Digital Elevation Model of the Shenandoah National Park and Surrounding Region, Virginia

    Science.gov (United States)

    Chirico, Peter G.; Tanner, Seth D.

    2004-01-01

    Explanation The purpose of developing a new 10m resolution DEM of the Shenandoah National Park Region was to more accurately depict geologic structure, surfical geology, and landforms of the Shenandoah National Park Region in preparation for automated landform classification. Previously, only a 30m resolution DEM was available through the National Elevation Dataset (NED). During production of the Shenandoah10m DEM of the Park the Geography Discipline of the USGS completed a revised 10m DEM to be included into the NED. However, different methodologies were used to produce the two similar DEMs. The ANUDEM algorithm was used to develop the Shenadoah DEM data. This algorithm allows for the inclusion of contours, streams, rivers, lake and water body polygons as well as spot height data to control the elevation model. A statistical analysis using over 800 National Geodetic Survey (NGS) first and second order vertical control points reveals that the Shenandoah10m DEM, produced as a part of the Appalachian Blue Ridge Landscape project, has a vertical accuracy of ?4.87 meters. The metadata for the 10m NED data reports a vertical accuracy of ?7m. A table listing the NGS control points, the elevation comparison, and the RMSE for the Shenandoah10m DEM is provided. The process of automated terrain classification involves developing statistical signatures from the DEM for each type of surficial deposit and landform type. The signature will be a measure of several characteristics derived from the elevation data including slope, aspect, planform curvature, and profile curvature. The quality of the DEM is of critical importance when extracting terrain signatures. The highest possible horizontal and vertical accuracy is required. The more accurate Shenandoah 10m DEM can now be analyzed and integrated with the geologic observations to yield statistical correlations between the two in the development of landform and surface geology mapping projects.

  14. Modeling acquisition geometries with improved super-resolution in digital breast tomosynthesis

    Science.gov (United States)

    Acciavatti, Raymond J.; Wileyto, E. Paul; Maidment, Andrew D. A.

    2016-03-01

    In digital breast tomosynthesis (DBT), a reconstruction is created from multiple x-ray projection images. Our previous work demonstrated that the reconstruction is capable of super-resolution (i.e., subpixel resolution) relative to the detector. In order for super-resolution to yield a reliable improvement in image quality, it should be achievable at all positions in the reconstruction. This paper demonstrates that super-resolution is not achievable at all depths, or at all heights above the breast support. For this purpose, a bar pattern phantom was imaged using a commercial DBT system. A goniometry stand was used to orient the long axis of the parallel bars along an oblique plane relative to the breast support. This setup allowed a single test frequency to be visualized over a continuous range of depths. The orientation of the test frequency was parallel to the direction of x-ray tube motion. An oblique reconstruction in the plane of the bar pattern phantom showed that the existence of super-resolution is depth-dependent. To identify design strategies for optimizing super-resolution, a theoretical model was then developed in which a test frequency higher than the alias frequency of the detector was simulated. Two design modifications that improve super-resolution are identified. In particular, it is shown that reducing the spacing between the x-ray source positions minimizes the number of depths lacking super-resolution. Additionally, introducing detector motion along the direction perpendicular to the breast support allows for more uniform super-resolution throughout the image volume. In conclusion, this work presents strategies for optimizing super-resolution in DBT.

  15. Sensorless Modeling of Varying Pulse Width Modulator Resolutions in Three-Phase Induction Motors.

    Science.gov (United States)

    Marko, Matthew David; Shevach, Glenn

    2017-01-01

    A sensorless algorithm was developed to predict rotor speeds in an electric three-phase induction motor. This sensorless model requires a measurement of the stator currents and voltages, and the rotor speed is predicted accurately without any mechanical measurement of the rotor speed. A model of an electric vehicle undergoing acceleration was built, and the sensorless prediction of the simulation rotor speed was determined to be robust even in the presence of fluctuating motor parameters and significant sensor errors. Studies were conducted for varying pulse width modulator resolutions, and the sensorless model was accurate for all resolutions of sinusoidal voltage functions.

  16. Robust Hydrological Forecasting for High-resolution Distributed Models Using a Unified Data Assimilation Approach

    Science.gov (United States)

    Hernandez, F.; Liang, X.

    2017-12-01

    Reliable real-time hydrological forecasting, to predict important phenomena such as floods, is invaluable to the society. However, modern high-resolution distributed models have faced challenges when dealing with uncertainties that are caused by the large number of parameters and initial state estimations involved. Therefore, to rely on these high-resolution models for critical real-time forecast applications, considerable improvements on the parameter and initial state estimation techniques must be made. In this work we present a unified data assimilation algorithm called Optimized PareTo Inverse Modeling through Inverse STochastic Search (OPTIMISTS) to deal with the challenge of having robust flood forecasting for high-resolution distributed models. This new algorithm combines the advantages of particle filters and variational methods in a unique way to overcome their individual weaknesses. The analysis of candidate particles compares model results with observations in a flexible time frame, and a multi-objective approach is proposed which attempts to simultaneously minimize differences with the observations and departures from the background states by using both Bayesian sampling and non-convex evolutionary optimization. Moreover, the resulting Pareto front is given a probabilistic interpretation through kernel density estimation to create a non-Gaussian distribution of the states. OPTIMISTS was tested on a low-resolution distributed land surface model using VIC (Variable Infiltration Capacity) and on a high-resolution distributed hydrological model using the DHSVM (Distributed Hydrology Soil Vegetation Model). In the tests streamflow observations are assimilated. OPTIMISTS was also compared with a traditional particle filter and a variational method. Results show that our method can reliably produce adequate forecasts and that it is able to outperform those resulting from assimilating the observations using a particle filter or an evolutionary 4D variational

  17. Mathematical modeling of Fe(II), Cu(II), Ni(II) and Zn(II) removal in a horizontal rotating tubular bioreactor.

    Science.gov (United States)

    Rezić, Tonči; Zeiner, Michaela; Santek, Božidar; Novak, Srđan

    2011-11-01

    Industrial wastewaters polluted with toxic heavy metals are serious ecological and environmental problem. Therefore, in this study multi-heavy metals (Fe(2+), Cu(2+), Ni(2+) and Zn(2+)) removal process with mixed microbial culture was examined in the horizontal rotating tubular bioreactor (HRTB) by different combinations of process parameters. Hydrodynamic conditions and biomass sorption capacity have main impact on the removal efficiency of heavy metals: Fe(2+) 95.5-79.0%, Ni(2+) 92.7-54.8%, Cu(2+) 87.7-54.9% and Zn(2+) 81.8-38.1%, respectively. On the basis of experimental results, integral mathematical model of removal heavy metals in the HRTB was established. It combines hydrodynamics (mixing), mass transfer and kinetics to define bioprocess conduction in the HRTB. Mixing in the HRTB was described by structured cascade model and metal ion removal by two combined diffusion-adsorption models, respectively. For Langmuir model, average variances between experimental and simulated concentrations of metal ions were in the range of 1.22-10.99 × 10(-3) and for the Freundlich model 0.12-3.98 × 10(-3), respectively. On the basis of previous facts, it is clear that developed integral bioprocess model with Freundlich model is more efficient in the prediction of concentration of metal ions in the HRTB. Furthermore, the results obtained also pointed out that the established model is at the same time accurate and robust and therefore it has great potential for use in the scale-up procedure.

  18. High Resolution Modeling of the Water Cycle to Refine GRACE Signal Analysis in the Gulf of Alaska Drainage

    Science.gov (United States)

    Beamer, J.; Hill, D. F.; Arendt, A. A.; Luthcke, S. B.; Liston, G. E.

    2015-12-01

    A comprehensive study of the Gulf of Alaska (GOA) drainage basin was carried out to improve understanding of the coastal freshwater discharge (FWD) and surface mass balance (SMB) of glaciers. Coastal FWD and SMB for all glacier surfaces were modeled using a suite of physically based, spatially distributed weather, energy-balance snow/ice melt, soil water balance, and runoff routing models at a high resolution (1 km horizontal grid; daily time step). A 35 year hind cast was performed, providing complete records of precipitation, runoff, snow water equivalent (SWE) depth, evapotranspiration, coastal FWD and glacier SMB. Meteorological forcing was provided by the North American Regional Reanalysis (NARR), Modern Era Retrospective Analysis for Research and Applications (MERRA), and NCEP Climate Forecast System Reanalysis (CFSR) datasets. A fourth dataset was created by bias-correcting the NARR data to recently-developed monthly weather grids based on PRISM climatologies (NARR-BC). Each weather dataset and model combination was individually calibrated using PRISM climatologies, streamflow, and glacier mass balance measurements from four locations in the study domain. Simulated mean annual FWD into the GOA ranged from 600 km3 yr-1 using NARR to 850 km3 yr-1 from NARR-BC. The CFSR-forced simulations with optimized model parameters produced a simulated regional water storage that compared favorably to data from the NASA/DLR Gravity Recovery and Climate Experiment (GRACE) high resolution mascon solutions (Figure). Glacier runoff, taken as the sum of rainfall, snow and ice melt occurring on glacier surfaces, ranged from 260 km3 yr-1 from MERRA to 400 km3 yr-1 from NARR-BC, approximately one half of the signal from both glaciers and surrounding terrain. The large contribution from non-glacier surfaces to the seasonal water balance is likely not being fully removed from GRACE solutions aimed at isolating the glacier signal alone. We will discuss methods to use our simulations

  19. The southern high-resolution modeling consortium - a source for research and operational collaboration

    Science.gov (United States)

    Gary L. Achtemeier; Scott L. Goodrick; Yongqiang Liu

    2003-01-01

    The Southern High-Resolution Modeling Consortium (SHRMC) is one of five regional Fire Consortia for Advanced Modeling of Meteorology and Smoke (FCAMMS) consortia established as part of the National Fire Plan. FCAMMS involves research and development activities collaborating across all land management agencies, NOAA, NASA, and Universities. These activities will support...

  20. Impact of climate change on river flooding assessed with different spatial model resolutions

    NARCIS (Netherlands)

    Booij, Martijn J.

    2005-01-01

    The impact of climate change on flooding in the river Meuse is assessed on a daily basis using spatially and temporally changed climate patterns and a hydrological model with three different spatial resolutions. This is achieved by selecting a hydrological modelling framework and implementing

  1. An object model for genome information at all levels of resolution

    Energy Technology Data Exchange (ETDEWEB)

    Honda, S.; Parrott, N.W.; Smith, R.; Lawrence, C.

    1993-12-31

    An object model for genome data at all levels of resolution is described. The model was derived by considering the requirements for representing genome related objects in three application domains: genome maps, large-scale DNA sequencing, and exploring functional information in gene and protein sequences. The methodology used for the object-oriented analysis is also described.

  2. Monte Carlo Bayesian Inference on a Statistical Model of Sub-Gridcolumn Moisture Variability using High-Resolution Cloud Observations

    Science.gov (United States)

    Norris, P. M.; da Silva, A. M., Jr.

    2016-12-01

    Norris and da Silva recently published a method to constrain a statistical model of sub-gridcolumn moisture variability using high-resolution satellite cloud data. The method can be used for large-scale model parameter estimation or cloud data assimilation (CDA). The gridcolumn model includes assumed-PDF intra-layer horizontal variability and a copula-based inter-layer correlation model. The observables used are MODIS cloud-top pressure, brightness temperature and cloud optical thickness, but the method should be extensible to direct cloudy radiance assimilation for a small number of channels. The algorithm is a form of Bayesian inference with a Markov chain Monte Carlo (MCMC) approach to characterizing the posterior distribution. This approach is especially useful in cases where the background state is clear but cloudy observations exist. In traditional linearized data assimilation methods, a subsaturated background cannot produce clouds via any infinitesimal equilibrium perturbation, but the Monte Carlo approach is not gradient-based and allows jumps into regions of non-zero cloud probability. In the example provided, the method is able to restore marine stratocumulus near the Californian coast where the background state has a clear swath. The new approach not only significantly reduces mean and standard deviation biases with respect to the assimilated observables, but also improves the simulated rotational-Ramman scattering cloud optical centroid pressure against independent (non-assimilated) retrievals from the OMI instrument. One obvious difficulty for the method, and other CDA methods, is the lack of information content in passive cloud observables on cloud vertical structure, beyond cloud-top and thickness, thus necessitating strong dependence on the background vertical moisture structure. It is found that a simple flow-dependent correlation modification due to Riishojgaard is helpful, better honoring inversion structures in the background state.

  3. Modelling hydrodynamics of horizontal flow steel slag filters designed to upgrade phosphorus removal in small wastewater treatment plants.

    Science.gov (United States)

    Barca, Cristian; Roche, Nicolas; Troesch, Stéphane; Andrès, Yves; Chazarenc, Florent

    2018-01-15

    Steel slag filters, if well designed and operated, may upgrade phosphorus removal in small wastewater treatment plants such as stabilization ponds and constructed wetlands. The main objective of this study was to develop a systemic modelling approach to describe changes in the hydraulic performances and internal hydrodynamics of steel slag filters under real dynamic operating conditions. The experimental retention time distribution curves (RTD curves) determined from tracer experiments performed at different times during the first year of operation of two field-scale steel slag filters were analyzed through a three stage process. First, a statistical analysis of the RTD curves was performed to determine statistical parameters of the retention time distribution. Second, classical tanks in series (TIS) and plug flow with dispersion (PFD) models were used to obtain a first evaluation of the dispersion and mixing regime. Finally, a multi-flow path TIS model, based on the assumption of several flow paths with different hydraulic properties, is proposed to accurately describe the internal hydrodynamics. Overall, the results of this study indicate that higher CaO content, round shape, and larger grain size distribution of steel slag may promote plug-like flow rather than dispersion. The results of the multi-flow path TIS model suggest that the internal hydrodynamics of steel slag filters can be primarily described by two main flow paths: (i) a faster main flow path showing higher plug flow, followed by (ii) a slower secondary flow path showing higher dispersion. The results also showed that internal hydrodynamics may change over time as a consequence of physical-chemical phenomena occurring in the filter, including accumulation of precipitates, slag hydration and carbonation, and particle segregation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. A Technology Pathway for Airbreathing, Combined-Cycle, Horizontal Space Launch Through SR-71 Based Trajectory Modeling

    Science.gov (United States)

    Kloesel, Kurt J.; Ratnayake, Nalin A.; Clark, Casie M.

    2011-01-01

    Access to space is in the early stages of commercialization. Private enterprises, mainly under direct or indirect subsidy by the government, have been making headway into the LEO launch systems infrastructure, of small-weight-class payloads of approximately 1000 lbs. These moderate gains have emboldened the launch industry and they are poised to move into the middle-weight class (roughly 5000 lbs). These commercially successful systems are based on relatively straightforward LOX-RP, two-stage, bi-propellant rocket technology developed by the government 40 years ago, accompanied by many technology improvements. In this paper we examine a known generic LOX-RP system with the focus on the booster stage (1st stage). The booster stage is then compared to modeled Rocket-Based and Turbine-Based Combined Cycle booster stages. The air-breathing propulsion stages are based on/or extrapolated from known performance parameters of ground tested RBCC (the Marquardt Ejector Ramjet) and TBCC (the SR-71/J-58 engine) data. Validated engine models using GECAT and SCCREAM are coupled with trajectory optimization and analysis in POST-II to explore viable launch scenarios using hypothetical aerospaceplane platform obeying the aerodynamic model of the SR-71. Finally, and assessment is made of the requisite research technology advances necessary for successful commercial and government adoption of combined-cycle engine systems for space access.

  5. Evaluation of the hydrological flow paths in a gravel bed filter modeling a horizontal subsurface flow wetland by using a multi-tracer experiment.

    Science.gov (United States)

    Birkigt, Jan; Stumpp, Christine; Małoszewski, Piotr; Nijenhuis, Ivonne

    2018-04-15

    In recent years, constructed wetland systems have become into focus as means of cost-efficient organic contaminant management. Wetland systems provide a highly reactive environment in which several removal pathways of organic chemicals may be present at the same time; however, specific elimination processes and hydraulic conditions are usually separately investigated and thus not fully understood. The flow system in a three dimensional pilot-scale horizontal subsurface constructed wetland was investigated applying a multi-tracer test combined with a mathematical model to evaluate the flow and transport processes. The results indicate the existence of a multiple flow system with two distinct flow paths through the gravel bed and a preferential flow at the bottom transporting 68% of tracer mass resulting from the inflow design of the model wetland system. There the removal of main contaminant chlorobenzene was up to 52% based on different calculation approaches. Determined retention times in the range of 22d to 32.5d the wetland has a heterogeneous flow pattern. Differences between simulated and measured tracer concentrations in the upper sediment indicate diffusion dominated processes due to stagnant water zones. The tracer study combining experimental evaluation with mathematical modeling demonstrated the complexity of flow and transport processes in the constructed wetlands which need to be taken into account during interpretation of the determining attenuation processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Modeling and inversion of PS-wave moveout asymmetry for tilted TI media: Part 1 - Horizontal TTI layer

    Digital Repository Service at National Institute of Oceanography (India)

    Dewangan, P.; Tsvankin, I.

    arrowright H11009, we add a denominator H208491+Cx2H20850 to the cubic term in equation C-14: H9004tPS = Ax + Bx 3 1+Cx2 , H2084920H20850 Figure 5. Polar plot H20849in kilometersH20850 of the offset xminH20849H9251H20850 for the model from Figure 3. The stars... FoothillsH20850. D108 DewanganandTsvankin Application of equation 1 produces reflection SS data with the traveltimes of SS primaries but generally distorted amplitudes. The moveout of the constructed SS-waves in common-midpoint H20849CMPH20850 geometry...

  7. Using Lie Symmetry Analysis to Solve a Problem That Models Mass Transfer from a Horizontal Flat Plate

    Directory of Open Access Journals (Sweden)

    W. Sinkala

    2012-01-01

    Full Text Available We use Lie symmetry analysis to solve a boundary value problem that arises in chemical engineering, namely, mass transfer during the contact of a solid slab with an overhead flowing fluid. This problem was earlier tackled using Adomian decomposition method (Fatoorehchi and Abolghasemi 2011, leading to the Adomian series form of solution. It turns out that the application of Lie group analysis yields an elegant form of the solution. After introducing the governing mathematical model and some preliminaries of Lie symmetry analysis, we compute the Lie point symmetries admitted by the governing equation and use these to construct the desired solution as an invariant solution.

  8. Comparison of Satellite NO2 Observations with High Resolution Model Simulations over the Balkan Peninsula

    International Nuclear Information System (INIS)

    Zyrichidou, I.; Koukouli, M. E.; Balis, D. S.; Katragkou, E.; Poupkou, A.; Kioutsioukis, I.; Markakis, K.; Melas, D.; van der A., R.; Boersma, F. K.; Roozendael, M. van

    2010-01-01

    High resolution model estimations of tropospheric NO 2 column amounts from the Comprehensive Air Quality Model (CAMx) were simulated for the Balkan Peninsula and were compared with satellite data for a period of one year, in order to study the characteristics of the spatial and temporal variability of pollution in the area. The Balkan area is considered a crossroad of different pollution sources and therefore has been divided in urban, industrial and rural regions, aiming to investigate the consistency of satellite retrievals and model predictions at high spatial resolution. Satellite measurements of tropospheric NO 2 are available daily at 13:30 LT since 2004 from OMI/Aura with a resolution of 13x24 km. The anthropogenic emissions used in CAMx for the domain under study, was compiled employing bottom-up approaches (road transport sector, off-road machinery) as well as other national registries and international databases. High resolution GIS maps (road network, landuses, population) were also used in order to achieve high spatial resolution. In most of the cases the model reveals similar spatial patterns with the satellite data, while over certain areas discrepancies were found and investigated.

  9. Analytical model of SiPM time resolution and order statistics with crosstalk

    Energy Technology Data Exchange (ETDEWEB)

    Vinogradov, S., E-mail: Sergey.Vinogradov@liverpool.ac.uk [University of Liverpool and Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Warrington WA4 4AD (United Kingdom); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Leninskiy Prospekt 53, Moscow (Russian Federation)

    2015-07-01

    Time resolution is the most important parameter of photon detectors in a wide range of time-of-flight and time correlation applications within the areas of high energy physics, medical imaging, and others. Silicon photomultipliers (SiPM) have been initially recognized as perfect photon-number-resolving detectors; now they also provide outstanding results in the scintillator timing resolution. However, crosstalk and afterpulsing introduce false secondary non-Poissonian events, and SiPM time resolution models are experiencing significant difficulties with that. This study presents an attempt to develop an analytical model of the timing resolution of an SiPM taking into account statistics of secondary events resulting from a crosstalk. Two approaches have been utilized to derive an analytical expression for time resolution: the first one based on statistics of independent identically distributed detection event times and the second one based on order statistics of these times. The first approach is found to be more straightforward and “analytical-friendly” to model analog SiPMs. Comparisons of coincidence resolving times predicted by the model with the known experimental results from a LYSO:Ce scintillator and a Hamamatsu MPPC are presented.

  10. Analytical model of SiPM time resolution and order statistics with crosstalk

    International Nuclear Information System (INIS)

    Vinogradov, S.

    2015-01-01

    Time resolution is the most important parameter of photon detectors in a wide range of time-of-flight and time correlation applications within the areas of high energy physics, medical imaging, and others. Silicon photomultipliers (SiPM) have been initially recognized as perfect photon-number-resolving detectors; now they also provide outstanding results in the scintillator timing resolution. However, crosstalk and afterpulsing introduce false secondary non-Poissonian events, and SiPM time resolution models are experiencing significant difficulties with that. This study presents an attempt to develop an analytical model of the timing resolution of an SiPM taking into account statistics of secondary events resulting from a crosstalk. Two approaches have been utilized to derive an analytical expression for time resolution: the first one based on statistics of independent identically distributed detection event times and the second one based on order statistics of these times. The first approach is found to be more straightforward and “analytical-friendly” to model analog SiPMs. Comparisons of coincidence resolving times predicted by the model with the known experimental results from a LYSO:Ce scintillator and a Hamamatsu MPPC are presented

  11. Can Low-Resolution Airborne Laser Scanning Data Be Used to Model Stream Rating Curves?

    Directory of Open Access Journals (Sweden)

    Steve W. Lyon

    2015-03-01

    Full Text Available This pilot study explores the potential of using low-resolution (0.2 points/m2 airborne laser scanning (ALS-derived elevation data to model stream rating curves. Rating curves, which allow the functional translation of stream water depth into discharge, making them integral to water resource monitoring efforts, were modeled using a physics-based approach that captures basic geometric measurements to establish flow resistance due to implicit channel roughness. We tested synthetically thinned high-resolution (more than 2 points/m2 ALS data as a proxy for low-resolution data at a point density equivalent to that obtained within most national-scale ALS strategies. Our results show that the errors incurred due to the effect of low-resolution versus high-resolution ALS data were less than those due to flow measurement and empirical rating curve fitting uncertainties. As such, although there likely are scale and technical limitations to consider, it is theoretically possible to generate rating curves in a river network from ALS data of the resolution anticipated within national-scale ALS schemes (at least for rivers with relatively simple geometries. This is promising, since generating rating curves from ALS scans would greatly enhance our ability to monitor streamflow by simplifying the overall effort required.

  12. Toward a Unified Representation of Atmospheric Convection in Variable-Resolution Climate Models

    Energy Technology Data Exchange (ETDEWEB)

    Walko, Robert [Univ. of Miami, Coral Gables, FL (United States)

    2016-11-07

    The purpose of this project was to improve the representation of convection in atmospheric weather and climate models that employ computational grids with spatially-variable resolution. Specifically, our work targeted models whose grids are fine enough over selected regions that convection is resolved explicitly, while over other regions the grid is coarser and convection is represented as a subgrid-scale process. The working criterion for a successful scheme for representing convection over this range of grid resolution was that identical convective environments must produce very similar convective responses (i.e., the same precipitation amount, rate, and timing, and the same modification of the atmospheric profile) regardless of grid scale. The need for such a convective scheme has increased in recent years as more global weather and climate models have adopted variable resolution meshes that are often extended into the range of resolving convection in selected locations.

  13. High resolution climate simulations with the AWI Climate Model (AWI-CM)

    Science.gov (United States)

    Sein, Dmitry; Semmler, Tido; Danilov, Sergey; Rackow, Thomas; Sidorenko, Dmitry; Jung, Thomas

    2017-04-01

    The ocean component of AWI-CM (FESOM) uses unstructured meshes, which allows the use of variable resolutions without traditional nesting. Due to the flexibility of unstructured meshes, one needs to carefully design meshes so that the variable resolution can most efficiently improve the simulated results with the least possible computational cost. We propose a new approach to set up variable resolution, which uses the satellite-observed sea surface height variability to determine the regions where high resolution should be assigned. This approach is verified using both idealized experiments and ocean simulations. It will also become one of the standard mesh design methods for general FESOM users. The added value of the use of the high resolution ocean model is demonstrated by two different FESOM ocean setups (LR and HR) coupled with the atmospheric model ECHAM6. LR (low resolution) employs a coarse mesh with nominal resolution of about 100 km in the global ocean, about 25 km north of 50°N, about 35 km in the equatorial band, and moderate refinement along the coasts. HR (high resolution) uses a locally eddy-resolving mesh. Its design relies on the AVISO satellite altimetry product. The coarsest resolution on this mesh is set to 60 km, and the finest resolution is 10 km. The refinement was determined by a low-pass filtered SSH variance (SSHV) pattern derived from the AVISO data. Fine resolution is obtained in regions with high SSHV, including the pathways of main currents - the Gulf Stream, Kuroshio, Antarctic Circumpolar Current (ACC) and Agulhas Current. The HR mesh contains about 1.3 million surface grid nodes, which is close to the number of nodes on a 1/4° Mercator mesh (only wet nodes are dealt with on unstructured meshes). This mesh size ensures reasonably fast simulations with available computational resources. The AWI-CM simulations with the two global ocean setups were carried out in the framework of the PRIMAVERA EU project according to the High

  14. A SYSTEM DYNAMICS-BASED CONFLICT RESOLUTION MODEL FOR RIVER WATER QUALITY MANAGEMENT

    Directory of Open Access Journals (Sweden)

    M. Karamouz, M. Akhbari, A. Moridi, R. Kerachian

    2006-07-01

    Full Text Available System dynamics approach by simulating a bargaining process can be used for resolving conflict of interests in water quality management. This approach can be a powerful alternative for traditional approaches for conflict resolution, which often rely on classical game theory. Waste load allocation models for river water quality management determine the optimal monthly waste load allocation to each point load. Most of these approaches are based on the multi-objective optimization models and do not consider the existing conflicts. In this study, a system dynamics-based conflict resolution model is presented for monthly waste load allocation in river systems. In this model, the stakeholders and decision-makers negotiate with each other considering their relative authorities, aspirations and dissatisfactions. System dynamics approach is actually used for simulating the bargaining process among the players. The model incorporates the objectives and preferences of stakeholders and decision-makers of the system in the form of utility functions and could provide a final agreement among the players. To evaluate the spatial and temporal variation of the concentration of the water quality indicator in the system, a water quality simulation model is also linked to the conflict resolution model. In the proposed model, a pre-assigned utility is allocated to different water users and the results are evaluated using a simulation model. The allocated utilities are tested and adjusted in order to provide an agreement between the assumed utilities and the utilities assigned by the model. The proposed model is applied to the Karkheh River system located in the southwest of Iran. The results show that the model can effectively incorporate the preferences of the players in providing a final agreement and the runtime of the proposed model is much less than the classical conflict resolution models. It is also shown that the waste load allocation can significantly reduce

  15. Downscaled climate change projections with uncertainty assessment over India using a high resolution multi-model approach.

    Science.gov (United States)

    Kumar, Pankaj; Wiltshire, Andrew; Mathison, Camilla; Asharaf, Shakeel; Ahrens, Bodo; Lucas-Picher, Philippe; Christensen, Jens H; Gobiet, Andreas; Saeed, Fahad; Hagemann, Stefan; Jacob, Daniela

    2013-12-01

    This study presents the possible regional climate change over South Asia with a focus over India as simulated by three very high resolution regional climate models (RCMs). One of the most striking results is a robust increase in monsoon precipitation by the end of the 21st century but regional differences in strength. First the ability of RCMs to simulate the monsoon climate is analyzed. For this purpose all three RCMs are forced with ECMWF reanalysis data for the period 1989-2008 at a horizontal resolution of ~25 km. The results are compared against independent observations. In order to simulate future climate the models are driven by lateral boundary conditions from two global climate models (GCMs: ECHAM5-MPIOM and HadCM3) using the SRES A1B scenario, except for one RCM, which only used data from one GCM. The results are presented for the full transient simulation period 1970-2099 and also for several time slices. The analysis concentrates on precipitation and temperature over land. All models show a clear signal of gradually wide-spread warming throughout the 21st century. The ensemble-mean warming over India is 1.5°C at the end of 2050, whereas it is 3.9°C at the end of century with respect to 1970-1999. The pattern of projected precipitation changes shows considerable spatial variability, with an increase in precipitation over the peninsular of India and coastal areas and, either no change or decrease further inland. From the analysis of a larger ensemble of global climate models using the A1B scenario a wide spread warming (~3.2°C) and an overall increase (~8.5%) in mean monsoon precipitation by the end of the 21st century is very likely. The influence of the driving GCM on the projected precipitation change simulated with each RCM is as strong as the variability among the RCMs driven with one. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Impact of a simple parameterization of convective gravity-wave drag in a stratosphere-troposphere general circulation model and its sensitivity to vertical resolution

    Directory of Open Access Journals (Sweden)

    C. Bossuet

    1998-02-01

    Full Text Available Systematic westerly biases in the southern hemisphere wintertime flow and easterly equatorial biases are experienced in the Météo-France climate model. These biases are found to be much reduced when a simple parameterization is introduced to take into account the vertical momentum transfer through the gravity waves excited by deep convection. These waves are quasi-stationary in the frame of reference moving with convection and they propagate vertically to higher levels in the atmosphere, where they may exert a significant deceleration of the mean flow at levels where dissipation occurs. Sixty-day experiments have been performed from a multiyear simulation with the standard 31 levels for a summer and a winter month, and with a T42 horizontal resolution. The impact of this parameterization on the integration of the model is found to be generally positive, with a significant deceleration in the westerly stratospheric jet and with a reduction of the easterly equatorial bias. The sensitivity of the Météo-France climate model to vertical resolution is also investigated by increasing the number of vertical levels, without moving the top of the model. The vertical resolution is increased up to 41 levels, using two kinds of level distribution. For the first, the increase in vertical resolution concerns especially the troposphere (with 22 levels in the troposphere, and the second treats the whole atmosphere in a homogeneous way (with 15 levels in the troposphere; the standard version of 31 levels has 10 levels in the troposphere. A comparison is made between the dynamical aspects of the simulations. The zonal wind and precipitation are presented and compared for each resolution. A positive impact is found with the finer tropospheric resolution on the precipitation in the mid-latitudes and on the westerly stratospheric jet, but the general impact on the model climate is weak, the physical parameterizations used appear to be mostly independent to the

  17. Impact of a simple parameterization of convective gravity-wave drag in a stratosphere-troposphere general circulation model and its sensitivity to vertical resolution

    Directory of Open Access Journals (Sweden)

    C. Bossuet

    Full Text Available Systematic westerly biases in the southern hemisphere wintertime flow and easterly equatorial biases are experienced in the Météo-France climate model. These biases are found to be much reduced when a simple parameterization is introduced to take into account the vertical momentum transfer through the gravity waves excited by deep convection. These waves are quasi-stationary in the frame of reference moving with convection and they propagate vertically to higher levels in the atmosphere, where they may exert a significant deceleration of the mean flow at levels where dissipation occurs. Sixty-day experiments have been performed from a multiyear simulation with the standard 31 levels for a summer and a winter month, and with a T42 horizontal resolution. The impact of this parameterization on the integration of the model is found to be generally positive, with a significant deceleration in the westerly stratospheric jet and with a reduction of the easterly equatorial bias. The sensitivity of the Météo-France climate model to vertical resolution is also investigated by increasing the number of vertical levels, without moving the top of the model. The vertical resolution is increased up to 41 levels, using two kinds of level distribution. For the first, the increase in vertical resolution concerns especially the troposphere (with 22 levels in the troposphere, and the second treats the whole atmosphere in a homogeneous way (with 15 levels in the troposphere; the standard version of 31 levels has 10 levels in the troposphere. A comparison is made between the dynamical aspects of the simulations. The zonal wind and precipitation are presented and compared for each resolution. A positive impact is found with the finer tropospheric resolution on the precipitation in the mid-latitudes and on the westerly stratospheric jet, but the general impact on the model climate is weak, the physical parameterizations used appear to be mostly independent to the

  18. High-resolution modeling of coastal freshwater discharge and glacier mass balance in the Gulf of Alaska watershed

    Science.gov (United States)

    Beamer, J. P.; Hill, D. F.; Arendt, A.; Liston, G. E.

    2016-05-01

    A comprehensive study of the Gulf of Alaska (GOA) drainage basin was carried out to improve understanding of the coastal freshwater discharge (FWD) and glacier volume loss (GVL). Hydrologic processes during the period 1980-2014 were modeled using a suite of physically based, spatially distributed weather, energy-balance snow/ice melt, soil water balance, and runoff routing models at a high-resolution (1 km horizontal grid; daily time step). Meteorological forcing was provided by the North American Regional Reanalysis (NARR), Modern Era Retrospective Analysis for Research and Applications (MERRA), and Climate Forecast System Reanalysis (CFSR) data sets. Streamflow and glacier mass balance modeled using MERRA and CFSR compared well with observations in four watersheds used for calibration in the study domain. However, only CFSR produced regional seasonal and long-term trends in water balance that compared favorably with independent Gravity Recovery and Climate Experiment (GRACE) and airborne altimetry data. Mean annual runoff using CFSR was 760 km3 yr-1, 8% of which was derived from the long-term removal of stored water from glaciers (glacier volume loss). The annual runoff from CFSR was partitioned into 63% snowmelt, 17% glacier ice melt, and 20% rainfall. Glacier runoff, taken as the sum of rainfall, snow, and ice melt occurring each season on glacier surfaces, was 38% of the total seasonal runoff, with the remaining runoff sourced from nonglacier surfaces. Our simulations suggests that existing GRACE solutions, previously reported to represent glacier mass balance alone, are actually measuring the full water budget of land and ice surfaces.

  19. Validation of a global hydrodynamic flood inundation model against high resolution observation data of urban flooding

    Science.gov (United States)

    Bates, Paul; Sampson, Chris; Smith, Andy; Neal, Jeff

    2015-04-01

    In this work we present further validation results for a hyper-resolution global flood inundation model. We use a true hydrodynamic model that uses highly efficient numerical algorithms (LISFLOOD-FP) to simulate flood inundation at ~1km resolution globally and then use downscaling algorithms to determine flood extent and water depth at 3 seconds of arc spatial resolution (~90m at the equator). The global model has ~150 million cells and requires ~180 hours of CPU time for a 10 year simulation period. Terrain data are taken from a custom version of the SRTM data set that has been processed specifically for hydrodynamic modelling. Return periods of flood flows along the entire global river network are determined using: (1) empirical relationships between catchment characteristics and index flood magnitude in different hydroclimatic zones derived from global runoff data; and (2) an index flood growth curve, also empirically derived. Bankful return period flow is then used to set channel width and depth, and flood defence impacts are modelled using empirical relationships between GDP, urbanization and defence standard of protection. The results of these simulations are global flood hazard maps for a number of different return period events from 1 in 5 to 1 in 1000 years. This method has already been show to compare well to return period flood hazard maps derived from models built with high resolution and accuracy local data (Sampson et al., submitted), yet the output from the global flood model has not yet been compared to real flood observations. Whilst the spatial resolution of the global model is high given the size of the model domain, ~1km resolution is still coarse compared to the models typically used to simulate urban flooding and the data typically used to validate these (~25m or less). Comparison of the global model to real-world observations or urban flooding therefore represents an exceptionally stringent test of model skill. In this paper we therefore

  20. Last Glacial Maximum simulations over southern Africa using a variable-resolution global model: synoptic-scale verification

    CSIR Research Space (South Africa)

    Nkoana, R

    2015-09-01

    Full Text Available the paleoclimate of the Cape south coast region of South Africa using high resolution regional climate modelling. The model used for this purpose is a variable-resolution global atmospheric model, the conformal-cubic atmospheric model (CCAM), which has been...

  1. High resolution transmission spectroscopy as a diagnostic for Jovian exoplanet atmospheres: constraints from theoretical models

    Energy Technology Data Exchange (ETDEWEB)

    Kempton, Eliza M.-R. [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States); Perna, Rosalba [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Heng, Kevin, E-mail: kemptone@grinnell.edu [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2014-11-01

    We present high resolution transmission spectra of giant planet atmospheres from a coupled three-dimensional (3D) atmospheric dynamics and transmission spectrum model that includes Doppler shifts which arise from winds and planetary motion. We model Jovian planets covering more than two orders of magnitude in incident flux, corresponding to planets with 0.9-55 day orbital periods around solar-type stars. The results of our 3D dynamical models reveal certain aspects of high resolution transmission spectra that are not present in simple one-dimensional (1D) models. We find that the hottest planets experience strong substellar to anti-stellar (SSAS) winds, resulting in transmission spectra with net blueshifts of up to 3 km s{sup –1}, whereas less irradiated planets show almost no net Doppler shifts. We find only minor differences between transmission spectra for atmospheres with temperature inversions and those without. Compared to 1D models, peak line strengths are significantly reduced for the hottest atmospheres owing to Doppler broadening from a combination of rotation (which is faster for close-in planets under the assumption of tidal locking) and atmospheric winds. Finally, high resolution transmission spectra may be useful in studying the atmospheres of exoplanets with optically thick clouds since line cores for very strong transitions should remain optically thick to very high altitude. High resolution transmission spectra are an excellent observational test for the validity of 3D atmospheric dynamics models, because they provide a direct probe of wind structures and heat circulation. Ground-based exoplanet spectroscopy is currently on the verge of being able to verify some of our modeling predictions, most notably the dependence of SSAS winds on insolation. We caution that interpretation of high resolution transmission spectra based on 1D atmospheric models may be inadequate, as 3D atmospheric motions can produce a noticeable effect on the absorption

  2. Monte Carlo Bayesian Inference on a Statistical Model of Sub-Gridcolumn Moisture Variability Using High-Resolution Cloud Observations. Part 1: Method

    Science.gov (United States)

    Norris, Peter M.; Da Silva, Arlindo M.

    2016-01-01

    A method is presented to constrain a statistical model of sub-gridcolumn moisture variability using high-resolution satellite cloud data. The method can be used for large-scale model parameter estimation or cloud data assimilation. The gridcolumn model includes assumed probability density function (PDF) intra-layer horizontal variability and a copula-based inter-layer correlation model. The observables used in the current study are Moderate Resolution Imaging Spectroradiometer (MODIS) cloud-top pressure, brightness temperature and cloud optical thickness, but the method should be extensible to direct cloudy radiance assimilation for a small number of channels. The algorithm is a form of Bayesian inference with a Markov chain Monte Carlo (MCMC) approach to characterizing the posterior distribution. This approach is especially useful in cases where the background state is clear but cloudy observations exist. In traditional linearized data assimilation methods, a subsaturated background cannot produce clouds via any infinitesimal equilibrium perturbation, but the Monte Carlo approach is not gradient-based and allows jumps into regions of non-zero cloud probability. The current study uses a skewed-triangle distribution for layer moisture. The article also includes a discussion of the Metropolis and multiple-try Metropolis versions of MCMC.

  3. Role of land state in a high resolution mesoscale model for simulating the Uttarakhand heavy rainfall event over India

    Science.gov (United States)

    Rajesh, P. V.; Pattnaik, S.; Rai, D.; Osuri, K. K.; Mohanty, U. C.; Tripathy, S.

    2016-04-01

    In 2013, Indian summer monsoon witnessed a very heavy rainfall event (>30 cm/day) over Uttarakhand in north India, claiming more than 5000 lives and property damage worth approximately 40 billion USD. This event was associated with the interaction of two synoptic systems, i.e., intensified subtropical westerly trough over north India and north-westward moving monsoon depression formed over the Bay of Bengal. The event had occurred over highly variable terrain and land surface characteristics. Although global models predicted the large scale event, they failed to predict realistic location, timing, amount, intensity and distribution of rainfall over the region. The goal of this study is to assess the impact of land state conditions in simulating this severe event using a high resolution mesoscale model. The land conditions such as multi-layer soil moisture and soil temperature fields were generated from High Resolution Land Data Assimilation (HRLDAS) modelling system. Two experiments were conducted namely, (1) CNTL (Control, without land data assimilation) and (2) LDAS, with land data assimilation (i.e., with HRLDAS-based soil moisture and temperature fields) using Weather Research and Forecasting (WRF) modelling system. Initial soil moisture correlation and root mean square error for LDAS is 0.73 and 0.05, whereas for CNTL it is 0.63 and 0.053 respectively, with a stronger heat low in LDAS. The differences in wind and moisture transport in LDAS favoured increased moisture transport from Arabian Sea through a convectively unstable region embedded within two low pressure centers over Arabian Sea and Bay of Bengal. The improvement in rainfall is significantly correlated to the persistent generation of potential vorticity (PV) in LDAS. Further, PV tendency analysis confirmed that the increased generation of PV is due to the enhanced horizontal PV advection component rather than the diabatic heating terms due to modified flow fields. These results suggest that, two

  4. A multi-stage intelligent approach based on an ensemble of two-way interaction model for forecasting the global horizontal radiation of India

    International Nuclear Information System (INIS)

    Jiang, He; Dong, Yao; Xiao, Ling

    2017-01-01

    Highlights: • Ensemble learning system is proposed to forecast the global solar radiation. • LASSO is utilized as feature selection method for subset model. • GSO is used to select the weight vector aggregating the response of subset model. • A simple and efficient algorithm is designed based on thresholding function. • Theoretical analysis focusing on error rate is provided. - Abstract: Forecasting of effective solar irradiation has developed a huge interest in recent decades, mainly due to its various applications in grid connect photovoltaic installations. This paper develops and investigates an ensemble learning based multistage intelligent approach to forecast 5 days global horizontal radiation at four given locations of India. The two-way interaction model is considered with purpose of detecting the associated correlation between the features. The main structure of the novel method is the ensemble learning, which is based on Divide and Conquer principle, is applied to enhance the forecasting accuracy and model stability. An efficient feature selection method LASSO is performed in the input space with the regularization parameter selected by Cross-Validation. A weight vector which best represents the importance of each individual model in ensemble system is provided by glowworm swarm optimization. The combination of feature selection and parameter selection are helpful in creating the diversity of the ensemble learning. In order to illustrate the validity of the proposed method, the datasets at four different locations of the India are split into training and test datasets. The results of the real data experiments demonstrate the efficiency and efficacy of the proposed method comparing with other competitors.

  5. Investigations of the transportation characteristics of biomass fuel particles in a horizontal pipeline through CFD modelling and experimental measurement

    International Nuclear Information System (INIS)

    Gubba, S.R.; Ingham, D.B.; Larsen, K.J.; Ma, L.; Pourkashanian, M.; Qian, X.; Williams, A.; Yan, Y.

    2012-01-01

    Recent national and international emission legislations to reduce emissions of carbon dioxide are forcing power generation industries using coal to look at various alternatives, such as biomass and especially by co-firing techniques. Biomass is transported to the burners either mixed with the primary fuel, in general, coal, or used in dedicated pipelines. In both cases, transportation of biomass is difficult due to its composition, size, shape and physical behaviour in comparison to the transportation of coal. This study considers experimental measurements for biomass particle transportation in a pipeline with a transverse elbow and compares the results with those using computation fluid dynamic (CFD) techniques. Various materials: flour, willow, wood, bark and a mixture of flour and willow, have been considered in the present investigation. The experimental work was performed using the dynamic changes in the electrostatic charges of biomass particles in conjunction with correlation signal processing techniques. The CFD simulations were performed by considering the effects of gravity, non-spherical drag (based on estimated shape factor), detailed information of the particle distribution, particle wall collisions and particle–particle interactions. Good quantitative and qualitative agreement was obtained between the CFD simulations and the experimental data. It is concluded that particle–particle interactions are of less importance if the mass loading ratio of particles to air is less than 0.03. -- Highlights: ► Dispersed biomass particle transportation is studied using experiments and CFD. ► Inclusion of asphericity in the drag model clearly demonstrated the improvements. ► Gravity effects are found to be important for correct particle distribution in pipe lines. ► Inter-particle collisions were less important for mass loading ratios <0.05 kg/kg.

  6. Refinement of atomic models in high resolution EM reconstructions using Flex-EM and local assessment.

    Science.gov (United States)

    Joseph, Agnel Praveen; Malhotra, Sony; Burnley, Tom; Wood, Chris; Clare, Daniel K; Winn, Martyn; Topf, Maya

    2016-05-01

    As the resolutions of Three Dimensional Electron Microscopic reconstructions of biological macromolecules are being improved, there is a need for better fitting and refinement methods at high resolutions and robust approaches for model assessment. Flex-EM/MODELLER has been used for flexible fitting of atomic models in intermediate-to-low resolution density maps of different biological systems. Here, we demonstrate the suitability of the method to successfully refine structures at higher resolutions (2.5-4.5Å) using both simulated and experimental data, including a newly processed map of Apo-GroEL. A hierarchical refinement protocol was adopted where the rigid body definitions are relaxed and atom displacement steps are reduced progressively at successive stages of refinement. For the assessment of local fit, we used the SMOC (segment-based Manders' overlap coefficient) score, while the model quality was checked using the Qmean score. Comparison of SMOC profiles at different stages of refinement helped in detecting regions that are poorly fitted. We also show how initial model errors can have significant impact on the goodness-of-fit. Finally, we discuss the implementation of Flex-EM in the CCP-EM software suite. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. The sensitivity of ecosystem service models to choices of input data and spatial resolution

    Science.gov (United States)

    Bagstad, Kenneth J.; Cohen, Erika; Ancona, Zachary H.; McNulty, Steven; Sun, Ge

    2018-01-01

    Although ecosystem service (ES) modeling has progressed rapidly in the last 10–15 years, comparative studies on data and model selection effects have become more common only recently. Such studies have drawn mixed conclusions about whether different data and model choices yield divergent results. In this study, we compared the results of different models to address these questions at national, provincial, and subwatershed scales in Rwanda. We compared results for carbon, water, and sediment as modeled using InVEST and WaSSI using (1) land cover data at 30 and 300 m resolution and (2) three different input land cover datasets. WaSSI and simpler InVEST models (carbon storage and annual water yield) were relatively insensitive to the choice of spatial resolution, but more complex InVEST models (seasonal water yield and sediment regulation) produced large differences when applied at differing resolution. Six out of nine ES metrics (InVEST annual and seasonal water yield and WaSSI) gave similar predictions for at least two different input land cover datasets. Despite differences in mean values when using different data sources and resolution, we found significant and highly correlated results when using Spearman's rank correlation, indicating consistent spatial patterns of high and low values. Our results confirm and extend conclusions of past studies, showing that in certain cases (e.g., simpler models and national-scale analyses), results can be robust to data and modeling choices. For more complex models, those with different output metrics, and subnational to site-based analyses in heterogeneous environments, data and model choices may strongly influence study findings.

  8. Equivalent physical models and formulation of equivalent source layer in high-resolution EEG imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yao Dezhong [School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu City, 610054, Sichuan Province (China); He Bin [The University of Illinois at Chicago, IL (United States)

    2003-11-07

    In high-resolution EEG imaging, both equivalent dipole layer (EDL) and equivalent charge layer (ECL) assumed to be located just above the cortical surface have been proposed as high-resolution imaging modalities or as intermediate steps to estimate the epicortical potential. Presented here are the equivalent physical models of these two equivalent source layers (ESL) which show that the strength of EDL is proportional to the surface potential of the layer when the outside of the layer is filled with an insulator, and that the strength of ECL is the normal current of the layer when the outside is filled with a perfect conductor. Based on these equivalent physical models, closed solutions of ECL and EDL corresponding to a dipole enclosed by a spherical layer are given. These results provide the theoretical basis of ESL applications in high-resolution EEG mapping.

  9. Equivalent physical models and formulation of equivalent source layer in high-resolution EEG imaging.

    Science.gov (United States)

    Yao, Dezhong; He, Bin

    2003-11-07

    In high-resolution EEG imaging, both equivalent dipole layer (EDL) and equivalent charge layer (ECL) assumed to be located just above the cortical surface have been proposed as high-resolution imaging modalities or as intermediate steps to estimate the epicortical potential. Presented here are the equivalent physical models of these two equivalent source layers (ESL) which show that the strength of EDL is proportional to the surface potential of the layer when the outside of the layer is filled with an insulator, and that the strength of ECL is the normal current of the layer when the outside is filled with a perfect conductor. Based on these equivalent physical models, closed solutions of ECL and EDL corresponding to a dipole enclosed by a spherical layer are given. These results provide the theoretical basis of ESL applications in high-resolution EEG mapping.

  10. Towards multi-resolution global climate modeling with ECHAM6-FESOM. Part II: climate variability

    Science.gov (United States)

    Rackow, T.; Goessling, H. F.; Jung, T.; Sidorenko, D.; Semmler, T.; Barbi, D.; Handorf, D.

    2018-04-01

    This study forms part II of two papers describing ECHAM6-FESOM, a newly established global climate model with a unique multi-resolution sea ice-ocean component. While part I deals with the model description and the mean climate state, here we examine the internal climate variability of the model under constant present-day (1990) conditions. We (1) assess the internal variations in the model in terms of objective variability performance indices, (2) analyze variations in global mean surface temperature and put them in context to variations in the observed record, with particular emphasis on the recent warming slowdown, (3) analyze and validate the most common atmospheric and oceanic variability patterns, (4) diagnose the potential predictability of various climate indices, and (5) put the multi-resolution approach to the test by comparing two setups that differ only in oceanic resolution in the equatorial belt, where one ocean mesh keeps the coarse 1° resolution applied in the adjacent open-ocean regions and the other mesh is gradually refined to 0.25°. Objective variability performance indices show that, in the considered setups, ECHAM6-FESOM performs overall favourably compared to five well-established climate models. Internal variations of the global mean surface temperature in the model are consistent with observed fluctuations and suggest that the recent warming slowdown can be explained as a once-in-one-hundred-years event caused by internal climate variability; periods of strong cooling in the model (`hiatus' analogs) are mainly associated with ENSO-related variability and to a lesser degree also to PDO shifts, with the AMO playing a minor role. Common atmospheric and oceanic variability patterns are simulated largely consistent with their real counterparts. Typical deficits also found in other models at similar resolutions remain, in particular too weak non-seasonal variability of SSTs over large parts of the ocean and episodic periods of almost absent

  11. Self-modeling curve resolution (SMCR) by particle swarm optimization (PSO).

    Science.gov (United States)

    Shinzawa, Hideyuki; Jiang, Jian-Hui; Iwahashi, Makio; Noda, Isao; Ozaki, Yukihiro

    2007-07-09

    Particle swarm optimization (PSO) combined with alternating least squares (ALS) is introduced to self-modeling curve resolution (SMCR) in this study for effective initial estimate. The proposed method aims to search concentration profiles or pure spectra which give the best resolution result by PSO. SMCR sometimes yields insufficient resolution results by getting trapped in a local minimum with poor initial estimates. The proposed method enables to reduce an undesirable effect of the local minimum in SMCR due to the advantages of PSO. Moreover, a new criterion based on global phase angle is also proposed for more effective performance of SMCR. It takes full advantage of data structure, that is to say, a sequential change with respect to a perturbation can be considered in SMCR with the criterion. To demonstrate its potential, SMCR by PSO is applied to concentration-dependent near-infrared (NIR) spectra of mixture solutions of oleic acid (OA) and ethanol. Its curve resolution performances are compared with SMCR with evolving factor analysis (EFA). The results show that SMCR by PSO yields significantly better curve resolution performances than those by EFA. It is revealed that SMCR by PSO is less sensitive to a local minimum in SMCR and it can be a new effective tool for curve resolution analysis.

  12. On the impact of using high-resolution atmosphere models for GRACE de-aliasing

    Science.gov (United States)

    You, Wei; Kusche, Jürgen; Forootan, Ehsan; Eicker, Annette; Bollmeyer, Christoph; Ohlwein, Christian

    2015-04-01

    The accurate reduction of atmospheric mass change has an important impact on the quality of temporal gravity and mass change recovery using GRACE (Gravity Recovery and Climate Experiment) observations, both at longer (signal separation) and shorter (de-aliasing) time-scales. This impact will be even more important for GRACE-FO and future satellite gravimetry missions such as ESA's NGGM. Any major improvement of temporal gravity field models will likely necessitate improvements of the atmospheric de-aliasing models. The state-of-the-art methodology of atmospheric de-aliasing uses ECMWFop (European Centre for Medium-Range Weather Forecasts operational analysis) or ERA-Interim reanalysis data with spatial resolution of about 0.5°or 0.75°and 2-D or 3-D integration methods to compute atmosphere de-aliasing models. Yet it is suspected that this resolution may lead to errors, for example, due to insufficient orographic representation in mountainous regions. In this study, we focus on using high-resolution regional meteorological models like COSMO-EU (COnsortium for Small-Scale MOdelling) or the COSMO-REA6 reanalysis with spatial resolution of about 0.0625°or 0.055,°together with ERA-Interim to determine atmosphere de-aliasing models by 2-D and 3-D integration methods. The quality of the atmospheric de-aliasing models, derived from different input fields and integration techniques will be assessed. In particular, the impact of spatial resolution on the recovery of GRACE gravity fields will be evaluated.

  13. Quantifying the Representation Error of Land Biosphere Models using High Resolution Footprint Analyses and UAS Observations

    Science.gov (United States)

    Hanson, C. V.; Schmidt, A.; Law, B. E.; Moore, W.

    2015-12-01

    The validity of land biosphere model outputs rely on accurate representations of ecosystem processes within the model. Typically, a vegetation or land cover type for a given area (several Km squared or larger resolution), is assumed to have uniform properties. The limited spacial and temporal resolution of models prevents resolving finer scale heterogeneous flux patterns that arise from variations in vegetation. This representation error must be quantified carefully if models are informed through data assimilation in order to assign appropriate weighting of model outputs and measurement data. The representation error is usually only estimated or ignored entirely due to the difficulty in determining reasonable values. UAS based gas sensors allow measurements of atmospheric CO2 concentrations with unprecedented spacial resolution, providing a means of determining the representation error for CO2 fluxes empirically. In this study we use three dimensional CO2 concentration data in combination with high resolution footprint analyses in order to quantify the representation error for modelled CO2 fluxes for typical resolutions of regional land biosphere models. CO2 concentration data were collected using an Atlatl X6A hexa-copter, carrying a highly calibrated closed path infra-red gas analyzer based sampling system with an uncertainty of ≤ ±0.2 ppm CO2. Gas concentration data was mapped in three dimensions using the UAS on-board position data and compared to footprints generated using WRF 3.61. Chad Hanson, Oregon State University, Corvallis, OR Andres Schmidt, Oregon State University, Corvallis, OR Bev Law, Oregon State University, Corvallis, OR

  14. Descriptive and predictive evaluation of high resolution Markov chain precipitation models

    DEFF Research Database (Denmark)

    Sørup, Hjalte Jomo Danielsen; Madsen, Henrik; Arnbjerg-Nielsen, Karsten

    2012-01-01

    . Continuous modelling of the Markov process proved attractive because of a marked decrease in the number of parameters. Inclusion of seasonality into the continuous Markov chain model proved difficult. Monte Carlo simulations with the models show that it is very difficult for all the model formulations......A time series of tipping bucket recordings of very high temporal and volumetric resolution precipitation is modelled using Markov chain models. Both first and second‐order Markov models as well as seasonal and diurnal models are investigated and evaluated using likelihood based techniques....... The first‐order Markov model seems to capture most of the properties of precipitation, but inclusion of seasonal and diurnal variation improves the model. Including a second‐order Markov Chain component does improve the descriptive capabilities of the model, but is very expensive in its parameter use...

  15. Obtaining high-resolution stage forecasts by coupling large-scale hydrologic models with sensor data

    Science.gov (United States)

    Fries, K. J.; Kerkez, B.

    2017-12-01

    We investigate how "big" quantities of distributed sensor data can be coupled with a large-scale hydrologic model, in particular the National Water Model (NWM), to obtain hyper-resolution forecasts. The recent launch of the NWM provides a great example of how growing computational capacity is enabling a new generation of massive hydrologic models. While the NWM spans an unprecedented spatial extent, there remain many questions about how to improve forecast at the street-level, the resolution at which many stakeholders make critical decisions. Further, the NWM runs on supercomputers, so water managers who may have access to their own high-resolution measurements may not readily be able to assimilate them into the model. To that end, we ask the question: how can the advances of the large-scale NWM be coupled with new local observations to enable hyper-resolution hydrologic forecasts? A methodology is proposed whereby the flow forecasts of the NWM are directly mapped to high-resolution stream levels using Dynamical System Identification. We apply the methodology across a sensor network of 182 gages in Iowa. Of these sites, approximately one third have shown to perform well in high-resolution flood forecasting when coupled with the outputs of the NWM. The quality of these forecasts is characterized using Principal Component Analysis and Random Forests to identify where the NWM may benefit from new sources of local observations. We also discuss how this approach can help municipalities identify where they should place low-cost sensors to most benefit from flood forecasts of the NWM.

  16. High-resolution modeling assessment of tidal stream resource in Western Passage of Maine, USA

    Science.gov (United States)

    Yang, Zhaoqing; Wang, Taiping; Feng, Xi; Xue, Huijie; Kilcher, Levi

    2017-04-01

    Although significant efforts have been taken to assess the maximum potential of tidal stream energy at system-wide scale, accurate assessment of tidal stream energy resource at project design scale requires detailed hydrodynamic simulations using high-resolution three-dimensional (3-D) numerical models. Extended model validation against high quality measured data is essential to minimize the uncertainties of the resource assessment. Western Passage in the State of Maine in U.S. has been identified as one of the top ranking sites for tidal stream energy development in U.S. coastal waters, based on a number of criteria including tidal power density, market value and transmission distance. This study presents an on-going modeling effort for simulating the tidal hydrodynamics in Western Passage using the 3-D unstructured-grid Finite Volume Community Ocean Model (FVCOM). The model domain covers a large region including the entire the Bay of Fundy with grid resolution varies from 20 m in the Western Passage to approximately 1000 m along the open boundary near the mouth of Bay of Fundy. Preliminary model validation was conducted using existing NOAA measurements within the model domain. Spatial distributions of tidal power density were calculated and extractable tidal energy was estimated using a tidal turbine module embedded in FVCOM under different tidal farm scenarios. Additional field measurements to characterize resource and support model validation were discussed. This study provides an example of high resolution resource assessment based on the guidance recommended by the International Electrotechnical Commission Technical Specification.

  17. The effect of re-solution models on fission gas disposition in irradiated UO2 fuel

    International Nuclear Information System (INIS)

    Wazzan, A.R.; Orkent, D.; Villalobos, A.

    1985-01-01

    A computer code developed earlier by Villalobos et al. to predict fission gas behavior in uranium oxide fuel under steady-state irradiation conditions and where bubble gas resolution is represented with the single knock-on model (SKO) is modified to replace the SKO model with the complete bubble destruction model (CBD). The CBD model required that bubble nucleation be included in the analysis. The revised code is used to compute gas release and total swelling. Both are found to be insensitive to whether they are obtained with the CBD or the SKO option. This is mainly because at low atomic percent of burnup, total swelling is dominated by the grain-edge bubble gas contribution, and release is dependent on the formation of a complete grainface/grain-edge tunnel network - factors that are not much affected by either the SKO or CBD models. At higher atomic percent of burnup, intragranular swelling, which can be sensitive to the re-solution model, contributes more to swelling. But even then, computations at 1.0 at .% burnup suggest total swelling will continue to be dominated by grain-edge gas. These results suggest that in modeling swelling and release in irradiated uranium dioxide fuel, the simpler SKO resolution model is satisfactory

  18. Constructing multi-resolution Markov State Models (MSMs) to elucidate RNA hairpin folding mechanisms.

    Science.gov (United States)

    Huang, Xuhui; Yao, Yuan; Bowman, Gregory R; Sun, Jian; Guibas, Leonidas J; Carlsson, Gunnar; Pande, Vijay S

    2010-01-01

    Simulating biologically relevant timescales at atomic resolution is a challenging task since typical atomistic simulations are at least two orders of magnitude shorter. Markov State Models (MSMs) provide one means of overcoming this gap without sacrificing atomic resolution by extracting long time dynamics from short simulations. MSMs coarse grain space by dividing conformational space into long-lived, or metastable, states. This is equivalent to coarse graining time by integrating out fast motions within metastable states. By varying the degree of coarse graining one can vary the resolution of an MSM; therefore, MSMs are inherently multi-resolution. Here we introduce a new algorithm Super-level-set Hierarchical Clustering (SHC), to our knowledge, the first algorithm focused on constructing MSMs at multiple resolutions. The key insight of this algorithm is to generate a set of super levels covering different density regions of phase space, then cluster each super level separately, and finally recombine this information into a single MSM. SHC is able to produce MSMs at different resolutions using different super density level sets. To demonstrate the power of this algorithm we apply it to a small RNA hairpin, generating MSMs at four different resolutions. We validate these MSMs by showing that they are able to reproduce the original simulation data. Furthermore, long time folding dynamics are extracted from these models. The results show that there are no metastable on-pathway intermediate states. Instead, the folded state serves as a hub directly connected to multiple unfolded/misfolded states which are separated from each other by large free energy barriers.

  19. High resolution global flood hazard map from physically-based hydrologic and hydraulic models.

    Science.gov (United States)

    Begnudelli, L.; Kaheil, Y.; McCollum, J.

    2017-12-01

    The global flood map published online at http://www.fmglobal.com/research-and-resources/global-flood-map at 90m resolution is being used worldwide to understand flood risk exposure, exercise certain measures of mitigation, and/or transfer the residual risk financially through flood insurance programs. The modeling system is based on a physically-based hydrologic model to simulate river discharges, and 2D shallow-water hydrodynamic model to simulate inundation. The model can be applied to large-scale flood hazard mapping thanks to several solutions that maximize its efficiency and the use of parallel computing. The hydrologic component of the modeling system is the Hillslope River Routing (HRR) hydrologic model. HRR simulates hydrological processes using a Green-Ampt parameterization, and is calibrated against observed discharge data from several publicly-available datasets. For inundation mapping, we use a 2D Finite-Volume Shallow-Water model with wetting/drying. We introduce here a grid Up-Scaling Technique (UST) for hydraulic modeling to perform simulations at higher resolution at global scale with relatively short computational times. A 30m SRTM is now available worldwide along with higher accuracy and/or resolution local Digital Elevation Models (DEMs) in many countries and regions. UST consists of aggregating computational cells, thus forming a coarser grid, while retaining the topographic information from the original full-resolution mesh. The full-resolution topography is used for building relationships between volume and free surface elevation inside cells and computing inter-cell fluxes. This approach almost achieves computational speed typical of the coarse grids while preserving, to a significant extent, the accuracy offered by the much higher resolution available DEM. The simulations are carried out along each river of the network by forcing the hydraulic model with the streamflow hydrographs generated by HRR. Hydrographs are scaled so that the peak

  20. Polarization Vision and the Development of Retinal Network Models. Neuronal Information Transfer Functions From Cones and Horizontal Cells to Bipolar Cells

    National Research Council Canada - National Science Library

    Kamermans, Maarten; Hawryshyn, Craig

    2008-01-01

    ... with. Furthermore, the study demonstrated how horizontal cells, that store global stimulus parameters such as spectral composition and e-vector orientation of the global stimulus, adjust the gains...

  1. Applying GIS and fine-resolution digital terrain models to assess three-dimensional population distribution under traffic impacts.

    Science.gov (United States)

    Wu, Chih-Da; Lung, Shih-Chun Candice

    2012-01-01

    Pollution exhibits significant variations horizontally and vertically within cities; therefore, the size and three-dimensional (3D) spatial distribution of population are significant determinants of urban health. This paper presents a novel methodology, 3D digital geography (3DIG) methodology, for investigating 3D spatial distributions of population in close proximity to traffic, thus the potential highly exposed population under traffic impacts. 3DIG applies geographic information system and fine-resolution (5 m) digital terrain models to obtain the number of building floors in residential zones of the Taipei metropolis; the vertical distribution of population at different floors was estimated based on demographic data in each census tract. In addition, population within 5, 10, 20, 50, and 100 m from the roadways was estimated. Field validation indicated that model results were reliable and accurate; the final population estimation differs only by 0.88% from the demographic database. The results showed that among the total 6.5 million Taipei residents, 0.8 (12.3%), 1.5 (22.9%), 2.3 (34.9), and 2.7 (41.1%) million residents live on the first or second floor within 5, 10, 20, and 50 m, respectively, of municipal roads. There are 22 census tracts with more than half of their residents living on the first or second floor within 5 m of municipal roads. In addition, half of the towns in Taipei city and county with >13.9% and 12.1% of residents live on the first and second floors within 5 m of municipal roads, respectively. These findings highlight the huge number of Taipei residents in close proximity to traffic and have significant implications for exposure assessment and environmental epidemiological studies. This study demonstrates that 3DIG is a versatile methodology for various research and policy planning in which 3D spatial population distribution is the central focus.

  2. High-resolution dynamical downscaling of re-analysis data over the Kerguelen Islands using the WRF model

    Science.gov (United States)

    Fonseca, Ricardo; Martín-Torres, Javier

    2018-03-01

    We have used the Weather Research and Forecasting (WRF) model to simulate the climate of the Kerguelen Islands (49° S, 69° E) and investigate its inter-annual variability. Here, we have dynamically downscaled 30 years of the Climate Forecast System Reanalysis (CFSR) over these islands at 3-km horizontal resolution. The model output is found to agree well with the station and radiosonde data at the Port-aux-Français station, the only location in the islands for which observational data is available. An analysis of the seasonal mean WRF data showed a general increase in precipitation and decrease in temperature with elevation. The largest seasonal rainfall amounts occur at the highest elevations of the Cook Ice Cap in winter where the summer mean temperature is around 0 °C. Five modes of variability are considered: conventional and Modoki El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Subtropical IOD (SIOD) and Southern Annular Mode (SAM). It is concluded that a key mechanism by which these modes impact the local climate is through interaction with the diurnal cycle in particular in the summer season when it has a larger magnitude. One of the most affected regions is the area just to the east of the Cook Ice Cap extending into the lower elevations between the Gallieni and Courbet Peninsulas. The WRF simulation shows that despite the small annual variability, the atmospheric flow in the Kerguelen Islands is rather complex which may also be the case for the other islands located in the Southern Hemisphere at similar latitudes.

  3. Horizontalidade e verticalidade: os modelos de improvisação de Pixinguinha e K-Ximbinho no choro brasileiro Horizontal and vertical structures: Pixinguinha and K-Ximbinho's models of improvisation in the Brazilian Music

    Directory of Open Access Journals (Sweden)

    Paula Veneziano Valente

    2011-06-01

    Full Text Available Análise sobre os procedimentos de improvisação utilizados por Pixinguinha em 1 x 0 (1947 e por K-Ximbinho em Velhos Companheiros (1981. Uma comparação das diferenças e semelhanças entre suas abordagens mostra uma preferência pelos modelos estilísticos vertical ou horizontal.Analysis of the improvisation procedures of Brazilian instrumentalists Pixinguinha in 1 x 0 (One to zero; 1947 and K-Ximbinho in Velhos Companheiros (Old pals; 1981. A comparison of differences and similarities in their approaches reveals a preference for horizontal or vertical stylistic models.

  4. Key features of the IPSL ocean atmosphere model and its sensitivity to atmospheric resolution

    Energy Technology Data Exchange (ETDEWEB)

    Marti, Olivier; Braconnot, P.; Bellier, J.; Brockmann, P.; Caubel, A.; Noblet, N. de; Friedlingstein, P.; Idelkadi, A.; Kageyama, M. [Unite Mixte CEA-CNRS-UVSQ, IPSL/LSCE, Gif-sur-Yvette Cedex (France); Dufresne, J.L.; Bony, S.; Codron, F.; Fairhead, L.; Grandpeix, J.Y.; Hourdin, F.; Musat, I. [Unite Mixte CNRS-Ecole Polytechnique-ENS-UPCM, IPSL/LMD, Paris Cedex 05 (France); Benshila, R.; Guilyardi, E.; Levy, C.; Madec, G.; Mignot, J.; Talandier, C. [unite mixte CNRS-IRD-UPMC, IPLS/LOCEAN, Paris Cedex 05 (France); Cadule, P.; Denvil, S.; Foujols, M.A. [Institut Pierre Simon Laplace des Sciences de l' Environnement (IPSL), Paris Cedex 05 (France); Fichefet, T.; Goosse, H. [Universite Catholique de Louvain, Institut d' Astronomie et de Geophysique Georges Lemaitre, Louvain-la-Neuve (Belgium); Krinner, G. [Unite mixte CNRS-UJF Grenoble, LGGE, BP96, Saint-Martin-d' Heres (France); Swingedouw, D. [CNRS/CERFACS, Toulouse (France)

    2010-01-15

    This paper presents the major characteristics of the Institut Pierre Simon Laplace (IPSL) coupled ocean-atmosphere general circulation model. The model components and the coupling methodology are described, as well as the main characteristics of the climatology and interannual variability. The model results of the standard version used for IPCC climate projections, and for intercomparison projects like the Paleoclimate Modeling Intercomparison Project (PMIP 2) are compared to those with a higher resolution in the atmosphere. A focus on the North Atlantic and on the tropics is used to address the impact of the atmosphere resolution on processes and feedbacks. In the North Atlantic, the resolution change leads to an improved representation of the storm-tracks and the North Atlantic oscillation. The better representation of the wind structure increases the northward salt transports, the deep-water formation and the Atlantic meridional overturning circulation. In the tropics, the ocean-atmosphere dynamical coupling, or Bjerknes feedback, improves with the resolution. The amplitude of ENSO (El Nino-Southern oscillation) consequently increases, as the damping processes are left unchanged. (orig.)

  5. Model Building to Facilitate Understanding of Holliday Junction and Heteroduplex Formation, and Holliday Junction Resolution

    Science.gov (United States)

    Selvarajah, Geeta; Selvarajah, Susila

    2016-01-01

    Students frequently expressed difficulty in understanding the molecular mechanisms involved in chromosomal recombination. Therefore, we explored alternative methods for presenting the two concepts of the double-strand break model: Holliday junction and heteroduplex formation, and Holliday junction resolution. In addition to a lecture and…

  6. Wind turbine large-eddy simulations on very coarse grid resolutions using an actuator line model

    NARCIS (Netherlands)

    Martínez-Tossas, Luis A.; Stevens, Richard J.A.M.; Meneveau, Charles

    2016-01-01

    In this work the accuracy of the Actuator Line Model (ALM) in Large Eddy Simulations of wind turbine flow is studied under the specific conditions of very coarse spatial resolutions. For finely-resolved conditions, it is known that ALM provides better accuracy compared to the standard Actuator Disk

  7. Wind Farm Large-Eddy Simulations on Very Coarse Grid Resolutions using an Actuator Line Model

    NARCIS (Netherlands)

    Martinez, L.A.; Meneveau, C.; Stevens, Richard Johannes Antonius Maria

    2016-01-01

    In this work the accuracy of the Actuator Line Model (ALM) in Large Eddy Simula- tions of wind turbine flow is studied under the speci c conditions of very coarse spatial resolutions. For finely-resolved conditions, it is known that ALM provides better accuracy compared to the standard Actuator Disk

  8. Role of land state in a high resolution mesoscale model for ...

    Indian Academy of Sciences (India)

    Land surface characteristics; high resolution mesoscale model; Uttarakhand rainfall; monsoon season. .... radiation flux at the. Analysis for Research and surface (SW). Applications (MERRA). Downward longwave radiation flux at the surface (LW). Rain rate (PCP) ...... cal diffusion package with an explicit treatment of.

  9. Higher surface mass balance of the Greenland ice sheet revealed by high-resolution climate modeling

    NARCIS (Netherlands)

    Ettema, J.|info:eu-repo/dai/nl/304831913; van den Broeke, M.R.|info:eu-repo/dai/nl/073765643; van Meijgaard, E.; van de Berg, W.J.|info:eu-repo/dai/nl/304831611; Bamber, Jonathan L.; Box, J.E.; Bales, R.C.

    2009-01-01

    High-resolution (∼11 km) regional climate modeling shows total annual precipitation on the Greenland ice sheet for 1958–2007 to be up to 24% and surface mass balance up to 63% higher than previously thought. The largest differences occur in coastal southeast Greenland, where the much higher

  10. A distributed stream temperature model using high resolution temperature observations (vol 11, pg 1469, 2007)

    NARCIS (Netherlands)

    Westhoff, M. C.; Savenije, H.G.; Luxemburg, W. M. J.; Stelling, G.S.; van de Giesen, N.C.; Selker, J. S.; Pfister, L.; Uhlenbrook, S.

    2007-01-01

    Distributed temperature data are used as input and as calibration data for an energy based temperature model of a first order stream in Luxembourg. A DTS (Distributed Temperature Sensing) system with a fiber optic cable of 1500m was used to measure stream water temperature with 1m resolution each 2

  11. Cloud-Based Tools to Support High-Resolution Modeling (Invited)

    Science.gov (United States)

    Jones, N.; Nelson, J.; Swain, N.; Christensen, S.

    2013-12-01

    The majority of watershed models developed to support decision-making by water management agencies are simple, lumped-parameter models. Maturity in research codes and advances in the computational power from multi-core processors on desktop machines, commercial cloud-computing resources, and supercomputers with thousands of cores have created new opportunities for employing more accurate, high-resolution distributed models for routine use in decision support. The barriers for using such models on a more routine basis include massive amounts of spatial data that must be processed for each new scenario and lack of efficient visualization tools. In this presentation we will review a current NSF-funded project called CI-WATER that is intended to overcome many of these roadblocks associated with high-resolution modeling. We are developing a suite of tools that will make it possible to deploy customized web-based apps for running custom scenarios for high-resolution models with minimal effort. These tools are based on a software stack that includes 52 North, MapServer, PostGIS, HT Condor, CKAN, and Python. This open source stack provides a simple scripting environment for quickly configuring new custom applications for running high-resolution models as geoprocessing workflows. The HT Condor component facilitates simple access to local distributed computers or commercial cloud resources when necessary for stochastic simulations. The CKAN framework provides a powerful suite of tools for hosting such workflows in a web-based environment that includes visualization tools and storage of model simulations in a database to archival, querying, and sharing of model results. Prototype applications including land use change, snow melt, and burned area analysis will be presented. This material is based upon work supported by the National Science Foundation under Grant No. 1135482

  12. Usefulness of high resolution coastal models for operational oil spill forecast: the "Full City" accident

    Directory of Open Access Journals (Sweden)

    G. Broström

    2011-11-01

    Full Text Available Oil spill modeling is considered to be an important part of a decision support system (DeSS for oil spill combatment and is useful for remedial action in case of accidents, as well as for designing the environmental monitoring system that is frequently set up after major accidents. Many accidents take place in coastal areas, implying that low resolution basin scale ocean models are of limited use for predicting the trajectories of an oil spill. In this study, we target the oil spill in connection with the "Full City" accident on the Norwegian south coast and compare operational simulations from three different oil spill models for the area. The result of the analysis is that all models do a satisfactory job. The "standard" operational model for the area is shown to have severe flaws, but by applying ocean forcing data of higher resolution (1.5 km resolution, the model system shows results that compare well with observations. The study also shows that an ensemble of results from the three different models is useful when predicting/analyzing oil spill in coastal areas.

  13. Performance of a TV white space database with different terrain resolutions and propagation models

    Directory of Open Access Journals (Sweden)

    A. M. Fanan

    2017-11-01

    Full Text Available Cognitive Radio has now become a realistic option for the solution of the spectrum scarcity problem in wireless communication. TV channels (the primary user can be protected from secondary-user interference by accurate prediction of TV White Spaces (TVWS by using appropriate propagation modelling. In this paper we address two related aspects of channel occupancy prediction for cognitive radio. Firstly we investigate the best combination of empirical propagation model and spatial resolution of terrain data for predicting TVWS by examining the performance of three propagation models (Extended-Hata, Davidson-Hata and Egli in the TV band 470 to 790 MHz along with terrain data resolutions of 1000, 100 and 30 m, when compared with a comprehensive set of propagation measurements taken in randomly-selected locations around Hull, UK. Secondly we describe how such models can be integrated into a database-driven tool for cognitive radio channel selection within the TVWS environment.

  14. Using High Resolution Model Data to Improve Lightning Forecasts across Southern California

    Science.gov (United States)

    Capps, S. B.; Rolinski, T.

    2014-12-01

    Dry lightning often results in a significant amount of fire starts in areas where the vegetation is dry and continuous. Meteorologists from the USDA Forest Service Predictive Services' program in Riverside, California are tasked to provide southern and central California's fire agencies with fire potential outlooks. Logistic regression equations were developed by these meteorologists several years ago, which forecast probabilities of lightning as well as lightning amounts, out to seven days across southern California. These regression equations were developed using ten years of historical gridded data from the Global Forecast System (GFS) model on a coarse scale (0.5 degree resolution), correlated with historical lightning strike data. These equations do a reasonably good job of capturing a lightning episode (3-5 consecutive days or greater of lightning), but perform poorly regarding more detailed information such as exact location and amounts. It is postulated that the inadequacies in resolving the finer details of episodic lightning events is due to the coarse resolution of the GFS data, along with limited predictors. Stability parameters, such as the Lifted Index (LI), the Total Totals index (TT), Convective Available Potential Energy (CAPE), along with Precipitable Water (PW) are the only parameters being considered as predictors. It is hypothesized that the statistical forecasts will benefit from higher resolution data both in training and implementing the statistical model. We have dynamically downscaled NCEP FNL (Final) reanalysis data using the Weather Research and Forecasting model (WRF) to 3km spatial and hourly temporal resolution across a decade. This dataset will be used to evaluate the contribution to the success of the statistical model of additional predictors in higher vertical, spatial and temporal resolution. If successful, we will implement an operational dynamically downscaled GFS forecast product to generate predictors for the resulting

  15. A seamless, high-resolution digital elevation model (DEM) of the north-central California coast

    Science.gov (United States)

    Foxgrover, Amy C.; Barnard, Patrick L.

    2012-01-01

    A seamless, 2-meter resolution digital elevation model (DEM) of the north-central California coast has been created from the most recent high-resolution bathymetric and topographic datasets available. The DEM extends approximately 150 kilometers along the California coastline, from Half Moon Bay north to Bodega Head. Coverage extends inland to an elevation of +20 meters and offshore to at least the 3 nautical mile limit of state waters. This report describes the procedures of DEM construction, details the input data sources, and provides the DEM for download in both ESRI Arc ASCII and GeoTIFF file formats with accompanying metadata.

  16. MODELING THE TRANSPORT AND CHEMICAL EVOLUTION OF ONSHORE AND OFFSHORE EMISSIONS AND THEIR IMPACT ON LOCAL AND REGIONAL AIR QUALITY USING A VARIABLE-GRID-RESOLUTION AIR QUALITY MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Kiran Alapaty

    2003-12-01

    This document, the project's first semiannual report, summarizes the research performed from 04/17/2003 through 10/16/2003. Portions of the research in several of the project's eight tasks were completed, and results obtained are briefly presented. We have tested the applicability of two different atmospheric boundary layer schemes for use in air quality model simulations. Preliminary analysis indicates that a scheme that uses sophisticated atmospheric boundary physics resulted in better simulation of atmospheric circulations. We have further developed and tested a new surface data assimilation technique to improve meteorological simulations, which will also result in improved air quality model simulations. Preliminary analysis of results indicates that using the new data assimilation technique results in reduced modeling errors in temperature and moisture. Ingestion of satellite-derived sea surface temperatures into the mesoscale meteorological model led to significant improvements in simulated clouds and precipitation compared to that obtained using traditional analyzed sea surface temperatures. To enhance the capabilities of an emissions processing system so that it can be used with our variable-grid-resolution air quality model, we have identified potential areas for improvements. Also for use in the variable-grid-resolution air quality model, we have tested a cloud module offline for its functionality, and have implemented and tested an efficient horizontal diffusion algorithm within the model.

  17. Restructuring of high-resolution satellite precipitation products for hydrological modeling

    Science.gov (United States)

    Chen, C. J.; Senarath, S. U. S.

    2014-12-01

    Most river basins of the world lack dense networks of precipitation gauges that produce high-quality precipitation data. In these basins, it is difficult to ensure systematic, unbiased hydrological modeling without relying on other sources of precipitation data. Although especially useful for data-scarce river basins, satellite-based precipitation still contains uncertainties that could propagate through hydrological modeling into simulated results, such as flow and stage. One of the main sources of uncertainty is the gridding process itself, typically associated with geo-statistical adjustments/calibrations founded on various interpolation schemes and ground-based measurements. Thus, the accuracy of a satellite precipitation product is inversely related to its resolution, both spatially and temporally. This also holds true for most gridded global/regional data sets. This study presents a method that integrates area-conservative regridding with fraction-redistribution to correct the satellite-based CMORPH data set (~8-km resolution and 30-minute time step) using rain-gauge-based APHRODITE (0.25 degree resolution and daily time step). This method can be broadly applied for refining any pairs of gridded data at different resolutions containing complementary information. Inter-comparison of modeled flow between the usage of the prior- and post-corrected CMORPH, APHRODITE, and gauge data is conducted spanning several orders of magnitude for catchments in Southeast Asia.

  18. The Resolution of Inflammation: A Mathematical Model of Neutrophil and Macrophage Interactions

    KAUST Repository

    Dunster, J. L.

    2014-07-23

    © 2014, Society for Mathematical Biology. There is growing interest in inflammation due to its involvement in many diverse medical conditions, including Alzheimer’s disease, cancer, arthritis and asthma. The traditional view that resolution of inflammation is a passive process is now being superceded by an alternative hypothesis whereby its resolution is an active, anti-inflammatory process that can be manipulated therapeutically. This shift in mindset has stimulated a resurgence of interest in the biological mechanisms by which inflammation resolves. The anti-inflammatory processes central to the resolution of inflammation revolve around macrophages and are closely related to pro-inflammatory processes mediated by neutrophils and their ability to damage healthy tissue. We develop a spatially averaged model of inflammation centring on its resolution, accounting for populations of neutrophils and macrophages and incorporating both pro- and anti-inflammatory processes. Our ordinary differential equation model exhibits two outcomes that we relate to healthy and unhealthy states. We use bifurcation analysis to investigate how variation in the system parameters affects its outcome. We find that therapeutic manipulation of the rate of macrophage phagocytosis can aid in resolving inflammation but success is critically dependent on the rate of neutrophil apoptosis. Indeed our model predicts that an effective treatment protocol would take a dual approach, targeting macrophage phagocytosis alongside neutrophil apoptosis.

  19. Improving temporal resolution of pulmonary perfusion imaging in rats using the partially separable functions model.

    Science.gov (United States)

    Brinegar, Cornelius; Schmitter, Sarah S; Mistry, Nilesh N; Johnson, G Allan; Liang, Zhi-Pei

    2010-10-01

    Dynamic contrast-enhanced MRI (or DCE-MRI) is a useful tool for measuring blood flow and perfusion, and it has found use in the study of pulmonary perfusion in animal models. However, DCE-MRI experiments are difficult in small animals such as rats. A recently developed method known as Interleaved Radial Imaging and Sliding window-keyhole (IRIS) addresses this problem by using a data acquisition scheme that covers (k,t)-space with data acquired from multiple bolus injections of a contrast agent. However, the temporal resolution of IRIS is limited by the effects of temporal averaging inherent in the sliding window and keyhole operations. This article describes a new method to cover (k,t)-space based on the theory of partially separable functions (PSF). Specifically, a sparse sampling of (k,t)-space is performed to acquire two data sets, one with high-temporal resolution and the other with extended k-space coverage. The high-temporal resolution training data are used to determine the temporal basis functions of the PSF model, whereas the other data set is used to determine the spatial variations of the model. The proposed method was validated by simulations and demonstrated by an experimental study. In this particular study, the proposed method achieved a temporal resolution of 32 msec.

  20. Towards Direct Simulation of Future Tropical Cyclone Statistics in a High-Resolution Global Atmospheric Model

    Directory of Open Access Journals (Sweden)

    Michael F. Wehner

    2010-01-01

    Full Text Available We present a set of high-resolution global atmospheric general circulation model (AGCM simulations focusing on the model's ability to represent tropical storms and their statistics. We find that the model produces storms of hurricane strength with realistic dynamical features. We also find that tropical storm statistics are reasonable, both globally and in the north Atlantic, when compared to recent observations. The sensitivity of simulated tropical storm statistics to increases in sea surface temperature (SST is also investigated, revealing that a credible late 21st century SST increase produced increases in simulated tropical storm numbers and intensities in all ocean basins. While this paper supports previous high-resolution model and theoretical findings that the frequency of very intense storms will increase in a warmer climate, it differs notably from previous medium and high-resolution model studies that show a global reduction in total tropical storm frequency. However, we are quick to point out that this particular model finding remains speculative due to a lack of radiative forcing changes in our time-slice experiments as well as a focus on the Northern hemisphere tropical storm seasons.

  1. Grid vs Mesh: The case of Hyper-resolution Modeling in Urban Landscapes

    Science.gov (United States)

    Grimley, L. E.; Tijerina, D.; Khanam, M.; Tiernan, E. D.; Frazier, N.; Ogden, F. L.; Steinke, R. C.; Maxwell, R. M.; Cohen, S.

    2017-12-01

    In this study, the relative performance of ADHydro and GSSHA was analyzed for a small and large rainfall event in an urban watershed called Dead Run near Baltimore, Maryland. ADHydro is a physics-based, distributed, hydrologic model that uses an unstructured mesh and operates in a high performance computing environment. The Gridded Surface/Subsurface Hydrological Analysis (GSSHA) model, which is maintained by the US Army Corps of Engineers, is a physics-based, distributed, hydrologic model that incorporates subsurface utilities and uses a structured mesh. A large portion of the work served as alpha-testing of ADHydro, which is under development by the CI-WATER modeling team at the University of Wyoming. Triangular meshes at variable resolutions were created to assess the sensitivity of ADHydro to changes in resolution and test the model's ability to handle a complicated urban routing network with structures present. ADHydro was compared with GSSHA which does not have the flexibility of an unstructured grid but does incorporate the storm drainage network. The modelled runoff hydrographs were compared to observed United States Geological Survey (USGS) stream gage data. The objective of this study was to analyze the effects of mesh type and resolution using ADHydro and GSSHA in simulations of an urban watershed.

  2. Comparison of elastic-viscous-plastic and viscous-plastic dynamics models using a high resolution Arctic sea ice model

    Energy Technology Data Exchange (ETDEWEB)

    Hunke, E.C. [Los Alamos National Lab., NM (United States); Zhang, Y. [Naval Postgraduate School, Monterey, CA (United States)

    1997-12-31

    A nonlinear viscous-plastic (VP) rheology proposed by Hibler (1979) has been demonstrated to be the most suitable of the rheologies commonly used for modeling sea ice dynamics. However, the presence of a huge range of effective viscosities hinders numerical implementations of this model, particularly on high resolution grids or when the ice model is coupled to an ocean or atmosphere model. Hunke and Dukowicz (1997) have modified the VP model by including elastic waves as a numerical regularization in the case of zero strain rate. This modification (EVP) allows an efficient, fully explicit discretization that adapts well to parallel architectures. The authors present a comparison of EVP and VP dynamics model results from two 5-year simulations of Arctic sea ice, obtained with a high resolution sea ice model. The purpose of the comparison is to determine how differently the two dynamics models behave, and to decide whether the elastic-viscous-plastic model is preferable for high resolution climate simulations, considering its high efficiency in parallel computation. Results from the first year of this experiment (1990) are discussed in detail in Hunke and Zhang (1997).

  3. An empirically grounded agent based model for modeling directs, conflict detection and resolution operations in air traffic management.

    Science.gov (United States)

    Bongiorno, Christian; Miccichè, Salvatore; Mantegna, Rosario N

    2017-01-01

    We present an agent based model of the Air Traffic Management socio-technical complex system aiming at modeling the interactions between aircraft and air traffic controllers at a tactical level. The core of the model is given by the conflict detection and resolution module and by the directs module. Directs are flight shortcuts that are given by air controllers to speed up the passage of an aircraft within a certain airspace and therefore to facilitate airline operations. Conflicts between flight trajectories can occur for two main reasons: either the planning of the flight trajectory was not sufficiently detailed to rule out all potential conflicts or unforeseen events during the flight require modifications of the flight plan that can conflict with other flight trajectories. Our model performs a local conflict detection and resolution procedure. Once a flight trajectory has been made conflict-free, the model searches for possible improvements of the system efficiency by issuing directs. We give an example of model calibration based on real data. We then provide an illustration of the capability of our model in generating scenario simulations able to give insights about the air traffic management system. We show that the calibrated model is able to reproduce the existence of a geographical localization of air traffic controllers' operations. Finally, we use the model to investigate the relationship between directs and conflict resolutions (i) in the presence of perfect forecast ability of controllers, and (ii) in the presence of some degree of uncertainty in flight trajectory forecast.

  4. An empirically grounded agent based model for modeling directs, conflict detection and resolution operations in air traffic management.

    Directory of Open Access Journals (Sweden)

    Christian Bongiorno

    Full Text Available We present an agent based model of the Air Traffic Management socio-technical complex system aiming at modeling the interactions between aircraft and air traffic controllers at a tactical level. The core of the model is given by the conflict detection and resolution module and by the directs module. Directs are flight shortcuts that are given by air controllers to speed up the passage of an aircraft within a certain airspace and therefore to facilitate airline operations. Conflicts between flight trajectories can occur for two main reasons: either the planning of the flight trajectory was not sufficiently detailed to rule out all potential conflicts or unforeseen events during the flight require modifications of the flight plan that can conflict with other flight trajectories. Our model performs a local conflict detection and resolution procedure. Once a flight trajectory has been made conflict-free, the model searches for possible improvements of the system efficiency by issuing directs. We give an example of model calibration based on real data. We then provide an illustration of the capability of our model in generating scenario simulations able to give insights about the air traffic management system. We show that the calibrated model is able to reproduce the existence of a geographical localization of air traffic controllers' operations. Finally, we use the model to investigate the relationship between directs and conflict resolutions (i in the presence of perfect forecast ability of controllers, and (ii in the presence of some degree of uncertainty in flight trajectory forecast.

  5. Theoretical limit of spatial resolution in diffuse optical tomography using a perturbation model

    International Nuclear Information System (INIS)

    Konovalov, A B; Vlasov, V V

    2014-01-01

    We have assessed the limit of spatial resolution of timedomain diffuse optical tomography (DOT) based on a perturbation reconstruction model. From the viewpoint of the structure reconstruction accuracy, three different approaches to solving the inverse DOT problem are compared. The first approach involves reconstruction of diffuse tomograms from straight lines, the second – from average curvilinear trajectories of photons and the third – from total banana-shaped distributions of photon trajectories. In order to obtain estimates of resolution, we have derived analytical expressions for the point spread function and modulation transfer function, as well as have performed a numerical experiment on reconstruction of rectangular scattering objects with circular absorbing inhomogeneities. It is shown that in passing from reconstruction from straight lines to reconstruction using distributions of photon trajectories we can improve resolution by almost an order of magnitude and exceed the accuracy of reconstruction of multi-step algorithms used in DOT. (optical tomography)

  6. Modelling high-resolution electron microscopy based on core-loss spectroscopy

    International Nuclear Information System (INIS)

    Allen, L.J.; Findlay, S.D.; Oxley, M.P.; Witte, C.; Zaluzec, N.J.

    2006-01-01

    There are a number of factors affecting the formation of images based on core-loss spectroscopy in high-resolution electron microscopy. We demonstrate unambiguously the need to use a full nonlocal description of the effective core-loss interaction for experimental results obtained from high angular resolution electron channelling electron spectroscopy. The implications of this model are investigated for atomic resolution scanning transmission electron microscopy. Simulations are used to demonstrate that core-loss spectroscopy images formed using fine probes proposed for future microscopes can result in images that do not correspond visually with the structure that has led to their formation. In this context, we also examine the effect of varying detector geometries. The importance of the contribution to core-loss spectroscopy images by dechannelled or diffusely scattered electrons is reiterated here

  7. The effect of different weather data sets and their resolution on climate-based daylight modelling

    DEFF Research Database (Denmark)

    Iversen, A; Svendsen, Svend; Nielsen, Toke Rammer

    2013-01-01

    Climate-based daylight modelling is based on the available weather data, which means that the weather data used as input to the daylight simulations are of great importance. In this paper, the effect on the outcome of the daylight simulations of using one weather data file rather than another...... for the same location was investigated. Furthermore, the effect of using weather data sets with an hourly resolution compared to a one-minute resolution was investigated. The results showed that the lighting dependencies varied by up to 2% depending on the chosen weather data file and indoor illuminance...... threshold. The energy consumption for artificial lighting was underestimated when simulating with time steps of hourly means compared to one-minute resolution. The findings from this comparison show that the dynamic, short-term effects of the weather have a surprisingly small impact on the simulation...

  8. Modeling the potential area of occupancy at fine resolution may reduce uncertainty in species range estimates

    DEFF Research Database (Denmark)

    Jiménez-Alfaro, Borja; Draper, David; Nogues, David Bravo

    2012-01-01

    resolution. To illustrate the ability of fine-resolution species distribution models for obtaining new measures of species ranges and their impact in conservation planning, we estimate the potential AOO of an endangered species in alpine environments. We use field occurrences of relict Empetrum nigrum......Area of Occupancy (AOO), is a measure of species geographical ranges commonly used for species red listing. In most cases, AOO is estimated using reported localities of species distributions at coarse grain resolution, providing measures subjected to uncertainties of data quality and spatial...... Area (MPA). As defined here, the potential AOO provides spatially-explicit measures of species ranges which are permanent in the time and scarcely affected by sampling bias. The overestimation of these measures may be reduced using higher thresholds of habitat suitability, but standard rules as the MPA...

  9. LTE modeling of inhomogeneous chromospheric structure using high-resolution limb observations

    Science.gov (United States)

    Lindsey, C.

    1987-01-01

    The paper discusses considerations relevant to LTE modeling of rough atmospheres. Particular attention is given to the application of recent high-resolution observations of the solar limb in the far-infrared and radio continuum to the modeling of chromospheric spicules. It is explained how the continuum limb observations can be combined with morphological knowledge of spicule structure to model the physical conditions in chromospheric spicules. This discussion forms the basis for a chromospheric model presented in a parallel publication based on observations ranging from 100 microns to 2.6 mm.

  10. Application of multi-scale wavelet entropy and multi-resolution Volterra models for climatic downscaling

    Science.gov (United States)

    Sehgal, V.; Lakhanpal, A.; Maheswaran, R.; Khosa, R.; Sridhar, Venkataramana

    2018-01-01

    This study proposes a wavelet-based multi-resolution modeling approach for statistical downscaling of GCM variables to mean monthly precipitation for five locations at Krishna Basin, India. Climatic dataset from NCEP is used for training the proposed models (Jan.'69 to Dec.'94) and are applied to corresponding CanCM4 GCM variables to simulate precipitation for the validation (Jan.'95-Dec.'05) and forecast (Jan.'06-Dec.'35) periods. The observed precipitation data is obtained from the India Meteorological Department (IMD) gridded precipitation product at 0.25 degree spatial resolution. This paper proposes a novel Multi-Scale Wavelet Entropy (MWE) based approach for clustering climatic variables into suitable clusters using k-means methodology. Principal Component Analysis (PCA) is used to obtain the representative Principal Components (PC) explaining 90-95% variance for each cluster. A multi-resolution non-linear approach combining Discrete Wavelet Transform (DWT) and Second Order Volterra (SoV) is used to model the representative PCs to obtain the downscaled precipitation for each downscaling location (W-P-SoV model). The results establish that wavelet-based multi-resolution SoV models perform significantly better compared to the traditional Multiple Linear Regression (MLR) and Artificial Neural Networks (ANN) based frameworks. It is observed that the proposed MWE-based clustering and subsequent PCA, helps reduce the dimensionality of the input climatic variables, while capturing more variability compared to stand-alone k-means (no MWE). The proposed models perform better in estimating the number of precipitation events during the non-monsoon periods whereas the models with clustering without MWE over-estimate the rainfall during the dry season.

  11. Dictionary learning based noisy image super-resolution via distance penalty weight model.

    Science.gov (United States)

    Han, Yulan; Zhao, Yongping; Wang, Qisong

    2017-01-01

    In this study, we address the problem of noisy image super-resolution. Noisy low resolution (LR) image is always obtained in applications, while most of the existing algorithms assume that the LR image is noise-free. As to this situation, we present an algorithm for noisy image super-resolution which can achieve simultaneously image super-resolution and denoising. And in the training stage of our method, LR example images are noise-free. For different input LR images, even if the noise variance varies, the dictionary pair does not need to be retrained. For the input LR image patch, the corresponding high resolution (HR) image patch is reconstructed through weighted average of similar HR example patches. To reduce computational cost, we use the atoms of learned sparse dictionary as the examples instead of original example patches. We proposed a distance penalty model for calculating the weight, which can complete a second selection on similar atoms at the same time. Moreover, LR example patches removed mean pixel value are also used to learn dictionary rather than just their gradient features. Based on this, we can reconstruct initial estimated HR image and denoised LR image. Combined with iterative back projection, the two reconstructed images are applied to obtain final estimated HR image. We validate our algorithm on natural images and compared with the previously reported algorithms. Experimental results show that our proposed method performs better noise robustness.

  12. Image reconstructions from super-sampled data sets with resolution modeling in PET imaging.

    Science.gov (United States)

    Li, Yusheng; Matej, Samuel; Metzler, Scott D

    2014-12-01

    Spatial resolution in positron emission tomography (PET) is still a limiting factor in many imaging applications. To improve the spatial resolution for an existing scanner with fixed crystal sizes, mechanical movements such as scanner wobbling and object shifting have been considered for PET systems. Multiple acquisitions from different positions can provide complementary information and increased spatial sampling. The objective of this paper is to explore an efficient and useful reconstruction framework to reconstruct super-resolution images from super-sampled low-resolution data sets. The authors introduce a super-sampling data acquisition model based on the physical processes with tomographic, downsampling, and shifting matrices as its building blocks. Based on the model, we extend the MLEM and Landweber algorithms to reconstruct images from super-sampled data sets. The authors also derive a backprojection-filtration-like (BPF-like) method for the super-sampling reconstruction. Furthermore, they explore variant methods for super-sampling reconstructions: the separate super-sampling resolution-modeling reconstruction and the reconstruction without downsampling to further improve image quality at the cost of more computation. The authors use simulated reconstruction of a resolution phantom to evaluate the three types of algorithms with different super-samplings at different count levels. Contrast recovery coefficient (CRC) versus background variability, as an image-quality metric, is calculated at each iteration for all reconstructions. The authors observe that all three algorithms can significantly and consistently achieve increased CRCs at fixed background variability and reduce background artifacts with super-sampled data sets at the same count levels. For the same super-sampled data sets, the MLEM method achieves better image quality than the Landweber method, which in turn achieves better image quality than the BPF-like method. The authors also demonstrate

  13. Characterisation of leukocytes in a human skin blister model of acute inflammation and resolution.

    Directory of Open Access Journals (Sweden)

    William Jenner

    Full Text Available There is an increasing need to understand the leukocytes and soluble mediators that drive acute inflammation and bring about its resolution in humans. We therefore carried out an extensive characterisation of the cantharidin skin blister model in healthy male volunteers. A novel fluorescence staining protocol was designed and implemented, which facilitated the identification of cell populations by flow cytometry. We observed that at the onset phase, 24 h after blister formation, the predominant cells were CD16hi/CD66b+ PMNs followed by HLA-DR+/CD14+ monocytes/macrophages, CD11c+ and CD141+ dendritic cells as well as Siglec-8+ eosinophils. CD3+ T cells, CD19+ B cells and CD56+ NK cells were also present, but in comparatively fewer numbers. During resolution, 72 h following blister induction, numbers of PMNs declined whilst the numbers of monocyte/macrophages remain unchanged, though they upregulated expression of CD16 and CD163. In contrast, the overall numbers of dendritic cells and Siglec-8+ eosinophils increased. Post hoc analysis of these data revealed that of the inflammatory cytokines measured, TNF-α but not IL-1β or IL-8 correlated with increased PMN numbers at the onset. Volunteers with the greatest PMN infiltration at onset displayed the fastest clearance rates for these cells at resolution. Collectively, these data provide insight into the cells that occupy acute resolving blister in humans, the soluble mediators that may control their influx as well as the phenotype of mononuclear phagocytes that predominate the resolution phase. Further use of this model will improve our understanding of the evolution and resolution of inflammation in humans, how defects in these over-lapping pathways may contribute to the variability in disease longevity/chronicity, and lends itself to the screen of putative anti-inflammatory or pro-resolution therapies.

  14. Characterisation of leukocytes in a human skin blister model of acute inflammation and resolution.

    Science.gov (United States)

    Jenner, William; Motwani, Madhur; Veighey, Kristin; Newson, Justine; Audzevich, Tatsiana; Nicolaou, Anna; Murphy, Sharon; Macallister, Raymond; Gilroy, Derek W

    2014-01-01

    There is an increasing need to understand the leukocytes and soluble mediators that drive acute inflammation and bring about its resolution in humans. We therefore carried out an extensive characterisation of the cantharidin skin blister model in healthy male volunteers. A novel fluorescence staining protocol was designed and implemented, which facilitated the identification of cell populations by flow cytometry. We observed that at the onset phase, 24 h after blister formation, the predominant cells were CD16hi/CD66b+ PMNs followed by HLA-DR+/CD14+ monocytes/macrophages, CD11c+ and CD141+ dendritic cells as well as Siglec-8+ eosinophils. CD3+ T cells, CD19+ B cells and CD56+ NK cells were also present, but in comparatively fewer numbers. During resolution, 72 h following blister induction, numbers of PMNs declined whilst the numbers of monocyte/macrophages remain unchanged, though they upregulated expression of CD16 and CD163. In contrast, the overall numbers of dendritic cells and Siglec-8+ eosinophils increased. Post hoc analysis of these data revealed that of the inflammatory cytokines measured, TNF-α but not IL-1β or IL-8 correlated with increased PMN numbers at the onset. Volunteers with the greatest PMN infiltration at onset displayed the fastest clearance rates for these cells at resolution. Collectively, these data provide insight into the cells that occupy acute resolving blister in humans, the soluble mediators that may control their influx as well as the phenotype of mononuclear phagocytes that predominate the resolution phase. Further use of this model will improve our understanding of the evolution and resolution of inflammation in humans, how defects in these over-lapping pathways may contribute to the variability in disease longevity/chronicity, and lends itself to the screen of putative anti-inflammatory or pro-resolution therapies.

  15. Using domain knowledge and domain-inspired discourse model for coreference resolution for clinical narratives.

    Science.gov (United States)

    Jindal, Prateek; Roth, Dan

    2013-01-01

    This paper presents a coreference resolution system for clinical narratives. Coreference resolution aims at clustering all mentions in a single document to coherent entities. A knowledge-intensive approach for coreference resolution is employed. The domain knowledge used includes several domain-specific lists, a knowledge intensive mention parsing, and task informed discourse model. Mention parsing allows us to abstract over the surface form of the mention and represent each mention using a higher-level representation, which we call the mention's semantic representation (SR). SR reduces the mention to a standard form and hence provides better support for comparing and matching. Existing coreference resolution systems tend to ignore discourse aspects and rely heavily on lexical and structural cues in the text. The authors break from this tradition and present a discourse model for "person" type mentions in clinical narratives, which greatly simplifies the coreference resolution. This system was evaluated on four different datasets which were made available in the 2011 i2b2/VA coreference challenge. The unweighted average of F1 scores (over B-cubed, MUC and CEAF) varied from 84.2% to 88.1%. These experiments show that domain knowledge is effective for different mention types for all the datasets. Error analysis shows that most of the recall errors made by the system can be handled by further addition of domain knowledge. The precision errors, on the other hand, are more subtle and indicate the need to understand the relations in which mentions participate for building a robust coreference system. This paper presents an approach that makes an extensive use of domain knowledge to significantly improve coreference resolution. The authors state that their system and the knowledge sources developed will be made publicly available.

  16. High-resolution Modeling Assisted Design of Customized and Individualized Transcranial Direct Current Stimulation Protocols

    Science.gov (United States)

    Bikson, Marom; Rahman, Asif; Datta, Abhishek; Fregni, Felipe; Merabet, Lotfi

    2012-01-01

    Objectives Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity currents facilitating or inhibiting spontaneous neuronal activity. tDCS is attractive since dose is readily adjustable by simply changing electrode number, position, size, shape, and current. In the recent past, computational models have been developed with increased precision with the goal to help customize tDCS dose. The aim of this review is to discuss the incorporation of high-resolution patient-specific computer modeling to guide and optimize tDCS. Methods In this review, we discuss the following topics: (i) The clinical motivation and rationale for models of transcranial stimulation is considered pivotal in order to leverage the flexibility of neuromodulation; (ii) The protocols and the workflow for developing high-resolution models; (iii) The technical challenges and limitations of interpreting modeling predictions, and (iv) Real cases merging modeling and clinical data illustrating the impact of computational models on the rational design of rehabilitative electrotherapy. Conclusions Though modeling for non-invasive brain stimulation is still in its development phase, it is predicted that with increased validation, dissemination, simplification and democratization of modeling tools, computational forward models of neuromodulation will become useful tools to guide the optimization of clinical electrotherapy. PMID:22780230

  17. Horizontal Branch stars as AmFm/HgMn stars

    OpenAIRE

    Michaud, G.; Richer, J.

    2008-01-01

    Recent observations and models for horizontal branch stars are briefly described and compared to models for AmFm stars. The limitations of those models are emphasized by a comparison to observations and models for HgMn stars.

  18. Mathematical modelling and numerical resolution of multi-phase compressible fluid flows problems

    International Nuclear Information System (INIS)

    Lagoutiere, Frederic

    2000-01-01

    This work deals with Eulerian compressible multi-species fluid dynamics, the species being either mixed or separated (with interfaces). The document is composed of three parts. The first parts devoted to the numerical resolution of model problems: advection equation, Burgers equation, and Euler equations, in dimensions one and two. The goal is to find a precise method, especially for discontinuous initial conditions, and we develop non dissipative algorithms. They are based on a downwind finite-volume discretization under some stability constraints. The second part treats of the mathematical modelling of fluids mixtures. We construct and analyse a set of multi-temperature and multi-pressure models that are entropy, symmetrizable, hyperbolic, not ever conservative. In the third part, we apply the ideas developed in the first part (downwind discretization) to the numerical resolution of the partial differential problems we have constructed for fluids mixtures in the second part. We present some numerical results in dimensions one and two. (author) [fr

  19. A Mathematical Model on the Resolution of Extrusion Bioprinting for the Development of New Bioinks

    Directory of Open Access Journals (Sweden)

    Ratima Suntornnond

    2016-09-01

    Full Text Available Pneumatic extrusion-based bioprinting is a recent and interesting technology that is very useful for biomedical applications. However, many process parameters in the bioprinter need to be fully understood in order to print at an adequate resolution. In this paper, a simple yet accurate mathematical model to predict the printed width of a continuous hydrogel line is proposed, in which the resolution is expressed as a function of nozzle size, pressure, and printing speed. A thermo-responsive hydrogel, pluronic F127, is used to validate the model predictions. This model could provide a platform for future correlation studies on pneumatic extrusion-based bioprinting as well as for developing new bioink formulations.

  20. Multi-Resolution Multimedia QoE Models for IPTV Applications

    Directory of Open Access Journals (Sweden)

    Prasad Calyam

    2012-01-01

    Full Text Available Internet television (IPTV is rapidly gaining popularity and is being widely deployed in content delivery networks on the Internet. In order to proactively deliver optimum user quality of experience (QoE for IPTV, service providers need to identify network bottlenecks in real time. In this paper, we develop psycho-acoustic-visual models that can predict user QoE of multimedia applications in real time based on online network status measurements. Our models are neural network based and cater to multi-resolution IPTV applications that include QCIF, QVGA, SD, and HD resolutions encoded using popular audio and video codec combinations. On the network side, our models account for jitter and loss levels, as well as router queuing disciplines: packet-ordered and time-ordered FIFO. We evaluate the performance of our multi-resolution multimedia QoE models in terms of prediction characteristics, accuracy, speed, and consistency. Our evaluation results demonstrate that the models are pertinent for real-time QoE monitoring and resource adaptation in IPTV content delivery networks.

  1. Quantifying uncertainty due to internal variability using high-resolution regional climate model simulations

    Science.gov (United States)

    Gutmann, E. D.; Ikeda, K.; Deser, C.; Rasmussen, R.; Clark, M. P.; Arnold, J. R.

    2015-12-01

    The uncertainty in future climate predictions is as large or larger than the mean climate change signal. As such, any predictions of future climate need to incorporate and quantify the sources of this uncertainty. One of the largest sources comes from the internal, chaotic, variability within the climate system itself. This variability has been approximated using the 30 ensemble members of the Community Earth System Model (CESM) large ensemble. Here we examine the wet and dry end members of this ensemble for cool-season precipitation in the Colorado Rocky Mountains with a set of high-resolution regional climate model simulations. We have used the Weather Research and Forecasting model (WRF) to simulate the periods 1990-2000, 2025-2035, and 2070-2080 on a 4km grid. These simulations show that the broad patterns of change depicted in CESM are inherited by the high-resolution simulations; however, the differences in the height and location of the mountains in the WRF simulation, relative to the CESM simulation, means that the location and magnitude of the precipitation changes are very different. We further show that high-resolution simulations with the Intermediate Complexity Atmospheric Research model (ICAR) predict a similar spatial pattern in the change signal as WRF for these ensemble members. We then use ICAR to examine the rest of the CESM Large Ensemble as well as the uncertainty in the regional climate model due to the choice of physics parameterizations.

  2. YUP.SCX: coaxing atomic models into medium resolution electron density maps.

    Science.gov (United States)

    Tan, Robert K-Z; Devkota, Batsal; Harvey, Stephen C

    2008-08-01

    The structures of large macromolecular complexes in different functional states can be determined by cryo-electron microscopy, which yields electron density maps of low to intermediate resolutions. The maps can be combined with high-resolution atomic structures of components of the complex, to produce a model for the complex that is more accurate than the formal resolution of the map. To this end, methods have been developed to dock atomic models into density maps rigidly or flexibly, and to refine a docked model so as to optimize the fit of the atomic model into the map. We have developed a new refinement method called YUP.SCX. The electron density map is converted into a component of the potential energy function to which terms for stereochemical restraints and volume exclusion are added. The potential energy function is then minimized (using simulated annealing) to yield a stereochemically-restrained atomic structure that fits into the electron density map optimally. We used this procedure to construct an atomic model of the 70S ribosome in the pre-accommodation state. Although some atoms are displaced by as much as 33A, they divide themselves into nearly rigid fragments along natural boundaries with smooth transitions between the fragments.

  3. Horizontal wells in subsurface remediation

    International Nuclear Information System (INIS)

    Losonsky, G.; Beljin, M.S.

    1992-01-01

    This paper reports on horizontal wells which offer an effective alternative to vertical wells in various environmental remediation technologies. Hydrogeological advantages of horizontal wells over vertical wells include a larger zone of influence, greater screen length, higher specific capacity and lower groundwater screen entrance velocity. Because of these advantages, horizontal wells can reduce treatment time and costs of groundwater recovery (pump-and-treat), in situ groundwater aeration (sparging) and soil gas extraction (vacuum extraction). Horizontal wells are also more effective than vertical wells in landfill leachate collection (under-drains), bioremediation, and horizontal grout injection

  4. Application of Radioxenon Stack Emission Data in High-Resolution Atmospheric Transport Modelling

    Science.gov (United States)

    Kusmierczyk-Michulec, J.; Schoeppner, M.; Kalinowski, M.; Bourgouin, P.; Kushida, N.; Barè, J.

    2017-12-01

    The Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) has developed the capability to run high-resolution atmospheric transport modelling by employing WRF and Flexpart-WRF. This new capability is applied to simulate the impact of stack emission data on simulated concentrations and how the availability of such data improves the overall accuracy of atmospheric transport modelling. The presented case study focuses on xenon-133 emissions from IRE, a medical isotope production facility in Belgium, and air concentrations detected at DEX33, a monitoring station close to Freiburg, Germany. The CTBTO is currently monitoring the atmospheric concentration of xenon-133 at 25 stations and will further expand the monitoring efforts to 40 stations worldwide. The incentive is the ability to detect xenon-133 that has been produced and released from a nuclear explosion. A successful detection can be used to prove the nuclear nature of an explosion and even support localization efforts. However, xenon-133 is also released from nuclear power plants and to a larger degree from medical isotope production facilities. The availability of stack emission data in combination with atmospheric transport modelling can greatly facilitate the understanding of xenon-133 concentrations detected at monitoring stations to distinguish between xenon-133 that has been emitted from a nuclear explosion and from civilian sources. Newly available stack emission data is used with a high-resolution version of the Flexpart atmospheric transport model, namely Flexpart-WRF, to assess the impact of the emissions on the detected concentrations and the advantage gained from the availability of such stack emission data. The results are analyzed with regard to spatial and time resolution of the high-resolution model and in comparison to conventional atmospheric transport models with and without stack emission data.

  5. High-resolution stochastic integrated thermal–electrical domestic demand model

    International Nuclear Information System (INIS)

    McKenna, Eoghan; Thomson, Murray

    2016-01-01

    Highlights: • A major new version of CREST’s demand model is presented. • Simulates electrical and thermal domestic demands at high-resolution. • Integrated structure captures appropriate time-coincidence of variables. • Suitable for low-voltage network and urban energy analyses. • Open-source development in Excel VBA freely available for download. - Abstract: This paper describes the extension of CREST’s existing electrical domestic demand model into an integrated thermal–electrical demand model. The principle novelty of the model is its integrated structure such that the timing of thermal and electrical output variables are appropriately correlated. The model has been developed primarily for low-voltage network analysis and the model’s ability to account for demand diversity is of critical importance for this application. The model, however, can also serve as a basis for modelling domestic energy demands within the broader field of urban energy systems analysis. The new model includes the previously published components associated with electrical demand and generation (appliances, lighting, and photovoltaics) and integrates these with an updated occupancy model, a solar thermal collector model, and new thermal models including a low-order building thermal model, domestic hot water consumption, thermostat and timer controls and gas boilers. The paper reviews the state-of-the-art in high-resolution domestic demand modelling, describes the model, and compares its output with three independent validation datasets. The integrated model remains an open-source development in Excel VBA and is freely available to download for users to configure and extend, or to incorporate into other models.

  6. Future precipitation in Portugal: high-resolution projections using WRF model and EURO-CORDEX multi-model ensembles

    Science.gov (United States)

    Soares, Pedro M. M.; Cardoso, Rita M.; Lima, Daniela C. A.; Miranda, Pedro M. A.

    2017-10-01

    Portugal, which is located in the west limit of the Mediterranean subtropics, is a small region with a complex orography with large precipitation gradients and interannual variability. In this study, the newer and higher resolution regional climate simulations, covering Portugal, are evaluated in present climate and used to investigate the rainfall projections for the end of the twenty-first century, following the RCP4.5 and RCP8.5 emission scenarios. The EURO-CORDEX historical simulations, at 0.11° and at 0.44° resolution, are evaluated against gridded observations of precipitation, which allows the assembly of four multi-model ensembles. An extra simulation, at even higher resolution (9 km) with WRF is also analysed. In present climate, the models are able to describe the precipitation temporal and spatial patterns as well its distributions, although there is a large spread and an overestimation of larger rainfall quantiles. The multi-model ensembles show that selecting the best performing models adds quality to the overall representation of rainfall. The high-resolution simulations augment the spatial details of precipitation, but objectively do not seem to add value with respect to the coarse resolution. Regarding the RCP8.5 scenario, WRF and the multi-model ensembles consistently predict important losses of precipitation in Portugal in spring, summer and autumn, ranging from -10% and -50%. For all seasons, the changes are more severe in the southern basins. The precipitation distributions show, for all models, important reductions of the contribution from low to moderate/high precipitation bins and augments of days with strong rainfall. Furthermore, a prominent growth of high-ranking percentiles is predicted reaching values over 70% in some regions. Generally, the changes associated with the RCP4.5 scenario have the same signal and features, but with smaller magnitudes.

  7. The sensitivity of biological finite element models to the resolution of surface geometry: a case study of crocodilian crania

    Science.gov (United States)

    Evans, Alistair R.; McHenry, Colin R.

    2015-01-01

    The reliability of finite element analysis (FEA) in biomechanical investigations depends upon understanding the influence of model assumptions. In producing finite element models, surface mesh resolution is influenced by the resolution of input geometry, and influences the resolution of the ensuing solid mesh used for numerical analysis. Despite a large number of studies incorporating sensitivity studies of the effects of solid mesh resolution there has not yet been any investigation into the effect of surface mesh resolution upon results in a comparative context. Here we use a dataset of crocodile crania to examine the effects of surface resolution on FEA results in a comparative context. Seven high-resolution surface meshes were each down-sampled to varying degrees while keeping the resulting number of solid elements constant. These models were then subjected to bite and shake load cases using finite element analysis. The results show that incremental decreases in surface resolution can result in fluctuations in strain magnitudes, but that it is possible to obtain stable results using lower resolution surface in a comparative FEA study. As surface mesh resolution links input geometry with the resulting solid mesh, the implication of these results is that low resolution input geometry and solid meshes may provide valid results in a comparative context. PMID:26056620

  8. The sensitivity of biological finite element models to the resolution of surface geometry: a case study of crocodilian crania

    Directory of Open Access Journals (Sweden)

    Matthew R. McCurry

    2015-06-01

    Full Text Available The reliability of finite element analysis (FEA in biomechanical investigations depends upon understanding the influence of model assumptions. In producing finite element models, surface mesh resolution is influenced by the resolution of input geometry, and influences the resolution of the ensuing solid mesh used for numerical analysis. Despite a large number of studies incorporating sensitivity studies of the effects of solid mesh resolution there has not yet been any investigation into the effect of surface mesh resolution upon results in a comparative context. Here we use a dataset of crocodile crania to examine the effects of surface resolution on FEA results in a comparative context. Seven high-resolution surface meshes were each down-sampled to varying degrees while keeping the resulting number of solid elements constant. These models were then subjected to bite and shake load cases using finite element analysis. The results show that incremental decreases in surface resolution can result in fluctuations in strain magnitudes, but that it is possible to obtain stable results using lower resolution surface in a comparative FEA study. As surface mesh resolution links input geometry with the resulting solid mesh, the implication of these results is that low resolution input geometry and solid meshes may provide valid results in a comparative context.

  9. Forecast skill of a high-resolution real-time mesoscale model designed for weather support of operations at Kennedy Space Center and Cape Canaveral Air Station

    Science.gov (United States)

    Taylor, Gregory E.; Zack, John W.; Manobianco, John

    1994-01-01

    NASA funded Mesoscale Environmental Simulations and Operations (MESO), Inc. to develop a version of the Mesoscale Atmospheric Simulation System (MASS). The model has been modified specifically for short-range forecasting in the vicinity of KSC/CCAS. To accomplish this, the model domain has been limited to increase the number of horizontal grid points (and therefore grid resolution) and the model' s treatment of precipitation, radiation, and surface hydrology physics has been enhanced to predict convection forced by local variations in surface heat, moisture fluxes, and cloud shading. The objective of this paper is to (1) provide an overview of MASS including the real-time initialization and configuration for running the data pre-processor and model, and (2) to summarize the preliminary evaluation of the model's forecasts of temperature, moisture, and wind at selected rawinsonde station locations during February 1994 and July 1994. MASS is a hydrostatic, three-dimensional modeling system which includes schemes to represent planetary boundary layer processes, surface energy and moisture budgets, free atmospheric long and short wave radiation, cloud microphysics, and sub-grid scale moist convection.

  10. The influence of air quality model resolution on health impact assessment for fine particulate matter and its components.

    Science.gov (United States)

    Li, Ying; Henze, Daven K; Jack, Darby; Kinney, Patrick L

    2016-02-01

    Health impact assessments for fine particulate matter (PM2.5) often rely on simulated concentrations generated from air quality models. However, at the global level, these models often run at coarse resolutions, resulting in underestimates of peak concentrations in populated areas. This study aims to quantitatively examine the influence of model resolution on the estimates of mortality attributable to PM 2.5 and its species in the USA. We use GEOS-Chem, a global 3-D model of atmospheric composition, to simulate the 2008 annual average concentrations of PM2.5 and its six species over North America. The model was run at a fine resolution of 0.5 × 0.66° and a coarse resolution of 2 × 2.5°, and mortality was calculated using output at the two resolutions. Using the fine-modeled concentrations, we estimate that 142,000 PM 2.5 -related deaths occurred in the USA in 2008, and the coarse resolution produces a national mortality estimate that is 8 % lower than the fine-model estimate. Our spatial analysis of mortality shows that coarse resolutions tend to substantially underestimate mortality in large urban centers. We also re-grid the fine-modeled concentrations to several coarser resolutions and repeat mortality calculation at these resolutions. We found that model resolution tends to have the greatest influence on mortality estimates associated with primary species and the least impact on dust-related mortality. Our findings provide evidence of possible biases in quantitative PM 2.5 health impact assessments in applications of global atmospheric models at coarse spatial resolutions.

  11. Evaluation of high-resolution forecasts with the non-hydrostaticnumerical weather prediction model Lokalmodell for urban air pollutionepisodes in Helsinki, Oslo and Valencia

    Directory of Open Access Journals (Sweden)

    B. Fay

    2006-01-01

    Full Text Available The operational numerical weather prediction model Lokalmodell LM with 7,km horizontal resolution was evaluated for forecasting meteorological conditions during observed urban air pollution episodes. The resolution was increased to experimental 2.8 km and 1.1 km resolution by one-way interactive nesting without introducing urbanisation of physiographic parameters or parameterisations. The episodes examined are two severe winter inversion-induced episodes in Helsinki in December 1995 and Oslo in January 2003, three suspended dust episodes in spring and autumn in Helsinki and Oslo, and a late-summer photochemical episode in the Valencia area. The evaluation was basically performed against observations and radiosoundings and focused on the LM skill at forecasting the key meteorological parameters characteristic for the specific episodes. These included temperature inversions, atmospheric stability and low wind speeds for the Scandinavian episodes and the development of mesoscale recirculations in the Valencia area. LM forecasts often improved due to higher model resolution especially in mountainous areas like Oslo and Valencia where features depending on topography like temperature, wind fields and mesoscale valley circulations were better described. At coastal stations especially in Helsinki, forecast gains were due to the improved physiographic parameters (land fraction, soil type, or roughness length. The Helsinki and Oslo winter inversions with extreme nocturnal inversion strengths of 18°C were not sufficiently predicted with all LM resolutions. In Helsinki, overprediction of surface temperatures and low-level wind speeds basically led to underpredicted inversion strength. In the Oslo episode, the situation was more complex involving erroneous temperature advection and mountain-induced effects for the higher resolutions. Possible explanations include the influence of the LM treatment of snow cover, sea ice and stability-dependence of transfer

  12. High-resolution global CO2 modeling: a comparison to GOSAT column CO2 retrievals

    Science.gov (United States)

    Baker, D. F.

    2010-12-01

    Over a year’s worth of column CO2 concentrations retrieved by the Japanese Greenhouse-gases Observing Satellite (GOSAT) are now available: with a global distribution and good sensitivity down to the surface, these data could provide an important new view of the functioning of the global carbon cycle. The retrievals seem to be corrupted by systematic errors with a magnitude of several ppm, however; to be truly useful, these biases must be greatly reduced before being used in atmospheric transport inversions. Here GOSAT column CO2 retrievals are compared to values from a high-resolution global atmospheric transport model; the residuals are correlated with a variety of factors (including aerosol optical depth, cloud coverage, surface type, and viewing geometry) globally, across a full year of data, to help identify systematic errors in the retrievals and attribute them to possible causes. This broad comparison to model data is meant to complement the comparison to in situ CO2 measurements and upward-looking Fourier spectrometer data currently being used to validate the retrievals at a relatively few times and locations. NASA’s GEOS5 analyzed meteorology products at 0.5° x 0.67° resolution (lat/lon) are used both to compute diurnally-varying land biospheric fluxes (with the SiB model) and to transport these fluxes through the atmosphere with the off-line PCTM model (40 vertical layers, also at 0.5° x 0.67°). Global fossil fuel fluxes with similarly-high spatial resolution, but low temporal resolution, plus monthly varying air-sea fluxes from an ocean model, are also transported. The net fluxes and CO2 fields are optimized at coarse scales in a Transcom-like time-dependent inversion to agree with data from the in situ CO2 measurement network before the GOSAT comparison is made.

  13. Uncertainty of soil erosion modelling using open source high resolution and aggregated DEMs

    Directory of Open Access Journals (Sweden)

    Arun Mondal

    2017-05-01

    Full Text Available Digital Elevation Model (DEM is one of the important parameters for soil erosion assessment. Notable uncertainties are observed in this study while using three high resolution open source DEMs. The Revised Universal Soil Loss Equation (RUSLE model has been applied to analysis the assessment of soil erosion uncertainty using open source DEMs (SRTM, ASTER and CARTOSAT and their increasing grid space (pixel size from the actual. The study area is a part of the Narmada river basin in Madhya Pradesh state, which is located in the central part of India and the area covered 20,558 km2. The actual resolution of DEMs is 30 m and their increasing grid spaces are taken as 90, 150, 210, 270 and 330 m for this study. Vertical accuracy of DEMs has been assessed using actual heights of the sample points that have been take