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Sample records for grounded gracefully program

  1. Grace Murray Hopper - Programming Pioneer

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 2. Grace Murray Hopper - Programming Pioneer. V Rajaraman. Article-in-a-Box Volume 6 Issue 2 February 2001 pp 2-3. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/006/02/0002-0003 ...

  2. The potential of ground gravity measurements to validate GRACE data

    Directory of Open Access Journals (Sweden)

    D. Crossley

    2003-01-01

    Full Text Available New satellite missions are returning high precision, time-varying, satellite measurements of the Earth’s gravity field. The GRACE mission is now in its calibration/- validation phase and first results of the gravity field solutions are imminent. We consider here the possibility of external validation using data from the superconducting gravimeters in the European sub-array of the Global Geodynamics Project (GGP as ‘ground truth’ for comparison with GRACE. This is a pilot study in which we use 14 months of 1-hour data from the beginning of GGP (1 July 1997 to 30 August 1998, when the Potsdam instrument was relocated to South Africa. There are 7 stations clustered in west central Europe, and one station, Metsahovi in Finland. We remove local tides, polar motion, local and global air pressure, and instrument drift and then decimate to 6-hour samples. We see large variations in the time series of 5–10µgal between even some neighboring stations, but there are also common features that correlate well over the 427-day period. The 8 stations are used to interpolate a minimum curvature (gridded surface that extends over the geographical region. This surface shows time and spatial coherency at the level of 2– 4µgal over the first half of the data and 1–2µgal over the latter half. The mean value of the surface clearly shows a rise in European gravity of about 3µgal over the first 150 days and a fairly constant value for the rest of the data. The accuracy of this mean is estimated at 1µgal, which compares favorably with GRACE predictions for wavelengths of 500 km or less. Preliminary studies of hydrology loading over Western Europe shows the difficulty of correlating the local hydrology, which can be highly variable, with large-scale gravity variations.Key words. GRACE, satellite gravity, superconducting gravimeter, GGP, ground truth

  3. Preliminary Results from Powell Research Group on Integrating GRACE Satellite and Ground-based Estimates of Groundwater Storage Changes

    Science.gov (United States)

    Scanlon, B. R.; Zhang, Z.; Reitz, M.; Rodell, M.; Sanford, W. E.; Save, H.; Wiese, D. N.; Croteau, M. J.; McGuire, V. L.; Pool, D. R.; Faunt, C. C.; Zell, W.

    2017-12-01

    Groundwater storage depletion is a critical issue for many of the major aquifers in the U.S., particularly during intense droughts. GRACE (Gravity Recovery and Climate Experiment) satellite-based estimates of groundwater storage changes have attracted considerable media attention in the U.S. and globally and interest in GRACE products continues to increase. For this reason, a Powell Research Group was formed to: (1) Assess variations in groundwater storage using a variety of GRACE products and other storage components (snow, surface water, and soil moisture) for major aquifers in the U.S., (2) Quantify long-term trends in groundwater storage from ground-based monitoring and regional and national modeling, and (3) Use ground-based monitoring and modeling to interpret GRACE water storage changes within the context of extreme droughts and over-exploitation of groundwater. The group now has preliminary estimates from long-term trends and seasonal fluctuations in water storage using different GRACE solutions, including CSR, JPL and GSFC. Approaches to quantifying uncertainties in GRACE data are included. This work also shows how GRACE sees groundwater depletion in unconfined versus confined aquifers, and plans for future work will link GRACE data to regional groundwater models. The wealth of ground-based observations for the U.S. provides a unique opportunity to assess the reliability of GRACE-based estimates of groundwater storage changes.

  4. Saving Grace - A Climate Change Documentary Education Program

    Science.gov (United States)

    Byrne, J. M.; McDaniel, S.; Graham, J.; Little, L.; Hoggan, J. C.

    2012-12-01

    Saving Grace conveys climate change knowledge from the best international scientists and social scientists using a series of new media formats. An Education and Communication Plan (ECP) has been developed to disseminate climate change knowledge on impacts, mitigation and adaptation for individuals, and for all sectors of society. The research team is seeking contacts with science and social science colleagues around the world to provide the knowledge base for the ECP. Poverty enslaves…and climate change has, and will, spread and deepen poverty to hundreds of millions of people, primarily in the developing world. And make no mistake; we are enslaving hundreds of millions of people in a depressing and debilitating poverty that in numbers will far surpass the horrors of the slave trade of past centuries. Saving Grace is the story of that poverty - and minimizing that poverty. Saving Grace stars the best of the world's climate researchers. Saving Grace presents the science; who, where and why of greenhouse gases that drive climate change; current and projected impacts of a changing climate around the world; and most important, solutions to the climate change challenges we face.

  5. Hydrology in Central Europe - a Comparison Between Data from the GRACE Satellite Mission and Ground Superconducting Gravimeters

    Science.gov (United States)

    Crossley, D.; de Linage, C.; Boy, J.-P.; Hinderer, J.

    2009-04-01

    The surface gravity field is subject to many influences of mass redistribution within the Earth system, operating at the microgal (10-8 m s-2) level and at timescales from minutes to years. We include deformation within the Earth (tides, polar motion), motions within the atmosphere (local, regional, and global loading; also mass attractions), the oceans (non-tidal currents), and near-surface hydrology derived from rainfall (local, regional, and global contributions). In central Europe a network of 7 superconducting gravimeters (the only instrument with the required resolution for this type of work) has been operating for many years, recording variations at the sub-microgal level. Hydrology is the largest component in the un-modelled residual signal, most of which comes from an area within a few hundred m of the instrument. We use data from 2002-2007 to construct a regionalized ground gravity data set that is analyzed by Principal Component (EOF) analysis to extract the predominantly seasonal signal common to all stations. This we compare with the GRACE-derived field using solutions from GFZ Potsdam, CSR Texas, and GRGS Toulouse. There is very good agreement on the phase of the two different types of data, but the amplitude of the ground signal is complicated by the local hydrology around several of the stations, which is both above and below the instrument. We show our most recent analysis and compare the results with the GLDAS global hydrology model from NASA.

  6. GRACE manual

    International Nuclear Information System (INIS)

    Ishikawa, T.; Kawabata, S.; Shimizu, Y.; Kaneko, T.; Kato, K.; Tanaka, H.

    1993-02-01

    This manual is composed of three kinds of objects, theoretical background for calculating the cross section of elementary process, usage and technical details of the GRACE system. Throughout this manual we take the tree level process e + e - → W + W - γ as an example, including the e ± -scalar boson interactions. The real FORTRAN source code for this process is attached in the relevant sections as well as the results of calculation, which might be a great help for understanding the practical use of the system. (J.P.N.)

  7. Ground-Water Protection and Monitoring Program

    International Nuclear Information System (INIS)

    Dresel, P.E.

    1995-01-01

    This section of the 1994 Hanford Site Environmental Report summarizes the ground-water protection and monitoring program strategy for the Hanford Site in 1994. Two of the key elements of this strategy are to (1) protect the unconfined aquifer from further contamination, and (2) conduct a monitoring program to provide early warning when contamination of ground water does occur. The monitoring program at Hanford is designed to document the distribution and movement of existing ground-water contamination and provides a historical baseline for evaluating current and future risk from exposure to the contamination and for deciding on remedial action options

  8. Ground-Water Protection and Monitoring Program

    Energy Technology Data Exchange (ETDEWEB)

    Dresel, P.E.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the ground-water protection and monitoring program strategy for the Hanford Site in 1994. Two of the key elements of this strategy are to (1) protect the unconfined aquifer from further contamination, and (2) conduct a monitoring program to provide early warning when contamination of ground water does occur. The monitoring program at Hanford is designed to document the distribution and movement of existing ground-water contamination and provides a historical baseline for evaluating current and future risk from exposure to the contamination and for deciding on remedial action options.

  9. Time Changes of the European Gravity Field from GRACE: A Comparison with Ground Measurements from Superconducting Gravimeters and with Hydrology Model Predictions

    Science.gov (United States)

    Hinderer, J.; Lemoine, Frank G.; Crossley, D.; Boy, J.-P.

    2004-01-01

    We investigate the time-variable gravity changes in Europe retrieved from the initial GRACE monthly solutions spanning a 18 month duration from April 2002 to October 2003. Gravity anomaly maps are retrieved in Central Europe from the monthly satellite solutions we compare the fields according to various truncation levels (typically between degree 10 and 20) of the initial fields (expressed in spherical harmonics to degree 120). For these different degrees, an empirical orthogonal function (EOF) decomposition of the time-variable gravity field leads us to its main spatial and temporal characteristics. We show that the dominant signal is found to be annual with an amplitude and a phase both in agreement with predictions in Europe modeled using snow and soil-moisture variations from recent hydrology models. We compare these GRACE gravity field changes to surface gravity observations from 6 superconducting gravimeters of the GGP (Global Geodynamics Project) European sub-network, with a special attention to loading corrections. Initial results suggest that all 3 data sets (GRACE, hydrology and GGP) are responding to annual changes in near-surface water in Europe of a few microGal (at length scales of approx.1000 km) that show a high value in winter and a summer minimum. We also point out that the GRACE gravity field evolution seems to indicate that there is a trend in gravity between summer 2002 and summer 2003 which can be related to the 2003 heatwave in Europe and its hydrological consequences (drought). Despite the limited time span of our analysis and the uncertainties in retrieving a regional solution from the network of gravimeters, the calibration and validation aspects of the GRACE data processing based on the annual hydrology cycle in Europe are in progress.

  10. Economy and Grace

    DEFF Research Database (Denmark)

    Pedersen, Else Marie Wiberg

    2015-01-01

    Luther develops his idea the grace of God in tandem with his idea of economy, and a society characterized by ethical and social values such as love of neighbour and caring for the poor. Hence, the reformer's search for a gracious God is developed along with his criticism of the current indulgence...... doctrine and the emerging 'oeconomia moderna'. Thus, building on a simul gratia et oeconomia, grace and economy simultaneously, Luther's reformation theology can be perceived as te intersection of an economy of grace and a horizontal social economy (works of love) in quotidian life that together constitute...

  11. GRACE with FORM

    International Nuclear Information System (INIS)

    Fujimoto, J.; Ishikawa, T.; Kato, K.; Kaneko, T.; Nakazawa, N..; Shimizu, Y.; Vermaseren, J.; Yasui, Y.

    2006-01-01

    A new version of GRACE/1-loop, a system for the automatic calculation of 1-loop Feynman diagrams, has been developed after the replacement of its symbolic manipulation engine from REDUCE to FORM. This enables us the efficient memory management that is essential for the handling of a tremendous number of Feynman diagrams, so that the performance of GRACE/1-loop is significantly improved as demonstrated in the text

  12. PVM-GRACE

    International Nuclear Information System (INIS)

    Yuasa, F.; Perret-Gallix, D.; Kawabata, S.; Ishikawa, T.

    1997-01-01

    We have implemented PVM in GRACE: an automatic Feynman diagram computation package, to benefit from the available CPU power distributed over a cluster of workstations as well as from a massive parallel machine. It is clearly shown that PVM-GRACE gives excellent performance in terms of reduction of elapsed time when the network overhead is kept small as compared to the processing time. (orig.)

  13. Grace and Courtesy and Beyond

    Science.gov (United States)

    Schaefer, Pat

    2015-01-01

    Taking up the cause of grace and courtesy across the planes of education, Pat Schaefer tells of the grace and courtesy of successive planes within a school culture and gives a glimpse of how the Montessori vision of a new society can look. Grace and courtesy go well beyond the practice of manners and into the topic of deep observation and…

  14. Contributions of GRACE to Climate Monitoring

    Science.gov (United States)

    Rodell, Matthew; Famiglietti, James; Chambers, Don P.; Wahr, John

    2011-01-01

    The NASA/German Gravity Recovery and Climate Experiment (GRACE) was launched in March 2002. Rather than looking downward, GRACE continuously monitors the locations of and precise distance between twin satellites which orbit in tandem about 200 km apart. Variations in mass near Earth's surface cause heterogeneities in its gravity field, which in turn affect the orbits of satellites. Thus scientists can use GRACE data to map Earth's gravity field with enough accuracy to discern month to month changes caused by ocean circulation and redistribution of water stored on and in the land. Other gravitational influences, such as atmospheric circulation, post-glacial rebound, and solid earth movements are either independently determined and removed or are negligible on a monthly to sub-decadal timescale. Despite its coarse spatial (>150,000 sq km at mid-latitudes) and temporal (approx monthly) resolutions, GRACE has enabled significant advancements in the oceanic, hydrologic, and cryospheric science, and has great potential for climate monitoring, because it is the only global observing system able to measure ocean bottom pressures, total terrestrial water storage, and ice mass changes. The best known GRACE results are estimates of Greenland and Antarctic ice sheet loss rates. Previously, scientists had estimated ice mass losses using ground and satellite based altimetry and surface mass balance estimates based on snowfall accumulation and glacier discharge. While such measurements are still very useful for their spatial detail, they are imperfectly correlated with large-scale ice mass changes, due to snow and ice compaction and incomplete spatial coverage. GRACE enables scientists to generate monthly time series of Greenland and Antarctic ice mass, which have confirmed the shrinking of the polar ice sheets, one of the most obvious and indisputable manifestations of climate change. Further, GRACE has located and quantified hot spots of ice loss in southeastern Greenland and

  15. Global inter-annual gravity changes from GRACE: Early results

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Hinderer, J.

    2005-01-01

    with an accuracy of 0.4 muGal corresponding to 9 mm water thickness on spatial scales longer than 1300 km. Four of the most widely used global hydrological models have been investigated for their spatial comparison with GRACE observations of inter-annual gravity field variations due to changes in continental water...... storage. The Global Land Data Assimilation System model has a spatial correlation coefficient with GRACE observations of 0.65 over the northern hemisphere. This demonstrates that the observed gravity field changes on these scales are largely related to changes in continental water storage.......Fifteen monthly gravity field solutions from the GRACE twin satellites launched more than two years ago have been studied to estimate gravity field changes between 2002 and 2003. The results demonstrate that GRACE is capable of capturing the changes in ground water on inter-annual scales...

  16. History of ground motion programs at the Nevada Test Site

    International Nuclear Information System (INIS)

    Banister, J.R.

    1984-01-01

    Some measurements were made in the atmospheric testing era, but the study of ground motion from nuclear tests became of wider interest after the instigation of underground testing. The ground motion generated by underground nuclear test has been investigated for a number of reasons including understanding basic phenomena, operational and safety concerns, yield determination, stimulation of earthquake concerns, and developing methods to aid in treaty verifications. This history of ground motion programs will include discussing early studies, high yield programs, Peaceful Nuclear Explosions tests, and some more recent developments. 6 references, 10 figures

  17. Multicultural Ground Teams in Space Programs

    Science.gov (United States)

    Maier, M.

    2012-01-01

    In the early years of space flight only two countries had access to space. In the last twenty years, there have been major changes in how we conduct space business. With the fall of the iron curtain and the growing of the European Union, more and more players were able to join the space business and space science. By end of the last century, numerous countries, agencies and companies earned the right to be equal partners in space projects. This paper investigates the impact of multicultural teams in the space arena. Fortunately, in manned spaceflight, especially for long duration missions, there are several studies and simulations reporting on multicultural team impact. These data have not been as well explored on the team interactions within the ground crews. The focus of this paper are the teams working on the ISS project. Hypotheses will be drawn from the results of space crew research to determine parallels and differences for this vital segment of success in space missions. The key source of the data will be drawn from structured interviews with managers and other ground crews on the ISS project.

  18. GRACE star camera noise

    Science.gov (United States)

    Harvey, Nate

    2016-08-01

    Extending results from previous work by Bandikova et al. (2012) and Inacio et al. (2015), this paper analyzes Gravity Recovery and Climate Experiment (GRACE) star camera attitude measurement noise by processing inter-camera quaternions from 2003 to 2015. We describe a correction to star camera data, which will eliminate a several-arcsec twice-per-rev error with daily modulation, currently visible in the auto-covariance function of the inter-camera quaternion, from future GRACE Level-1B product releases. We also present evidence supporting the argument that thermal conditions/settings affect long-term inter-camera attitude biases by at least tens-of-arcsecs, and that several-to-tens-of-arcsecs per-rev star camera errors depend largely on field-of-view.

  19. Using GRACE to constrain precipitation amount over cold mountainous basins

    Science.gov (United States)

    Behrangi, Ali; Gardner, Alex S.; Reager, John T.; Fisher, Joshua B.

    2017-01-01

    Despite the importance for hydrology and climate-change studies, current quantitative knowledge on the amount and distribution of precipitation in mountainous and high-elevation regions is limited due to instrumental and retrieval shortcomings. Here by focusing on two large endorheic basins in High Mountain Asia, we show that satellite gravimetry (Gravity Recovery and Climate Experiment (GRACE)) can be used to provide an independent estimate of monthly accumulated precipitation using mass balance equation. Results showed that the GRACE-based precipitation estimate has the highest agreement with most of the commonly used precipitation products in summer, but it deviates from them in cold months, when the other products are expected to have larger errors. It was found that most of the products capture about or less than 50% of the total precipitation estimated using GRACE in winter. Overall, Global Precipitation Climatology Project (GPCP) showed better agreement with GRACE estimate than other products. Yet on average GRACE showed 30% more annual precipitation than GPCP in the study basins. In basins of appropriate size with an absence of dense ground measurements, as is a typical case in cold mountainous regions, we find GRACE can be a viable alternative to constrain monthly and seasonal precipitation estimates from other remotely sensed precipitation products that show large bias.

  20. Canova's 'The Three Graces'

    Directory of Open Access Journals (Sweden)

    Marković Kamenko M.

    2009-01-01

    Full Text Available Antonio Canova (1757-1822, the epitome of the neo-classical style, was born in a small village Passagno in the province of Treviso. At the age of fourteen he started learning sculpture in Venice; at first, he was placed under Giovanni Bernardi and, later on, under Giovanni Ferrari. After he had established himself as a sculptor, he moved to Rome, the city of classisists in which he would later achieve a worldwide fame. The highest level of his art were the statues of naked women which exposed a new type of female beauty as well as a new poetic style based on the beauty conceived in ancient Greece. This work gives a story of one of Canova's unknown pieces. It is about a group of marble statues 'The Three Graces' which can be found in the Regional Museum of Art in Craiova. Not even a word has it been written referring to this particular sculpture in Romania. These are the first words about this piece of art, placed somewhere out of sight at a dark corner of the museum only because they do not possess any valid documentation concerning its purchase. Only the signature was left on it by the author; however, it is certain that it came to life a few years after he moved to London. The sculpture might have been made (around 1820 four or five years prior to his first marble group of statues 'The Three Graces' standing in the Hermitage Museum in St Petersburg.

  1. Ground Robotic Hand Applications for the Space Program study (GRASP)

    Science.gov (United States)

    Grissom, William A.; Rafla, Nader I. (Editor)

    1992-01-01

    This document reports on a NASA-STDP effort to address research interests of the NASA Kennedy Space Center (KSC) through a study entitled, Ground Robotic-Hand Applications for the Space Program (GRASP). The primary objective of the GRASP study was to identify beneficial applications of specialized end-effectors and robotic hand devices for automating any ground operations which are performed at the Kennedy Space Center. Thus, operations for expendable vehicles, the Space Shuttle and its components, and all payloads were included in the study. Typical benefits of automating operations, or augmenting human operators performing physical tasks, include: reduced costs; enhanced safety and reliability; and reduced processing turnaround time.

  2. An Economy of Grace

    Directory of Open Access Journals (Sweden)

    Victor Tan Chen

    2017-03-01

    Full Text Available This essay is adapted from a plenary talk the author gave at the “Growing Apart: The Implications of Economic Inequality” interdisciplinary conference at Boston College on 9 April 2016, as well as portions of his book Cut Loose: Jobless and Hopeless in an Unfair Economy, a sociological ethnography based on interviews and observations of unemployed autoworkers in Detroit, Michigan, and Windsor, Canada, during and after the Great Recession. The essay discusses four themes from this research. First, it provides a sociological understanding of how long-term unemployment and economic inequality are experienced by today’s less advantaged workers. Second, it illustrates how social policy can improve their circumstances. Third, it examines the limits of policy, and how dealing with inequality also requires changing the broader culture. Fourth, it makes the case for one possible approach to bring about that cultural change: a morality of grace.

  3. NASA 3D Models: GRACE

    Data.gov (United States)

    National Aeronautics and Space Administration — GRACE (Gravity Recovery and Climate Experiment), twin satellites launched in March 2002, are making detailed measurements of Earth's gravity field which will lead to...

  4. NASA 3D Models: Grace

    Data.gov (United States)

    National Aeronautics and Space Administration — GRACE (Gravity Recovery and Climate Experiment), twin satellites launched in March 2002, are making detailed measurements of Earth's gravity field which will lead to...

  5. Constellation Program Electrical Ground Support Equipment Research and Development

    Science.gov (United States)

    McCoy, Keegan S.

    2010-01-01

    At the Kennedy Space Center, I engaged in the research and development of electrical ground support equipment for NASA's Constellation Program. Timing characteristics playa crucial role in ground support communications. Latency and jitter are two problems that must be understood so that communications are timely and consistent within the Kennedy Ground Control System (KGCS). I conducted latency and jitter tests using Alien-Bradley programmable logic controllers (PLCs) so that these two intrinsic network properties can be reduced. Time stamping and clock synchronization also play significant roles in launch processing and operations. Using RSLogix 5000 project files and Wireshark network protocol analyzing software, I verified master/slave PLC Ethernet module clock synchronization, master/slave IEEE 1588 communications, and time stamping capabilities. All of the timing and synchronization test results are useful in assessing the current KGCS operational level and determining improvements for the future.

  6. GRACE Status at Mission End

    Science.gov (United States)

    Tapley, B. D.; Flechtner, F. M.; Watkins, M. M.; Bettadpur, S. V.

    2017-12-01

    The twin satellites of the Gravity Recovery and Climate Experiment (GRACE) were launched on March 17, 2002 and have operated for nearly 16 years. The mission objectives are to observe the spatial and temporal variations of the Earth's mass through its effects on the gravity field at the GRACE satellite altitude. The mass changes observed are related to both the changes within the solid earth and the change within and between the Erath system components. A significant cause of the time varying mass is water motion and the GRACE mission has provided a continuous decade long measurement sequence which characterizes the seasonal cycle of mass transport between the oceans, land, cryosphere and atmosphere; its inter-annual variability; and the climate driven secular, or long period, mass transport signals. The fifth reanalysis on the mission data set, the RL05 data, were released in mid-2013. With the planned launch of GRACE Follow-On in early 2018, plans are underway for a reanalysis that will be consistent with the GRACE FO processing standards. The mission is entering the final phases of its operation life with mission end expected to occur in early 2018. The current mission operations strategy emphasizes extending the mission lifetime to obtain an overlap with the GRACE FO. This presentation will review the mission status and the projections for mission lifetime, describe the current operations philosophy and its impact on the science data, discuss the issues related to achieving the GRACE and GRACE FO connection and discuss issues related to science data products during this phase of the mission period.

  7. Ground-source heat pump case studies and utility programs

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P.J.; Boyd, T.L.; Rogers, R.L.

    1995-04-01

    Ground-source heat pump systems are one of the promising new energy technologies that has shown rapid increase in usage over the past ten years in the United States. These systems offer substantial benefits to consumers and utilities in energy (kWh) and demand (kW) savings. The purpose of this study was to determine what existing monitored data was available mainly from electric utilities on heat pump performance, energy savings and demand reduction for residential, school and commercial building applications. In order to verify the performance, information was collected for 253 case studies from mainly utilities throughout the United States. The case studies were compiled into a database. The database was organized into general information, system information, ground system information, system performance, and additional information. Information was developed on the status of demand-side management of ground-source heat pump programs for about 60 electric utility and rural electric cooperatives on marketing, incentive programs, barriers to market penetration, number units installed in service area, and benefits.

  8. Remote Monitoring of Groundwater Overdraft Using GRACE and InSAR

    Science.gov (United States)

    Scher, C.; Saah, D.

    2017-12-01

    Gravity Recovery and Climate Experiment (GRACE) data paired with radar-derived analyses of volumetric changes in aquifer storage capacity present a viable technique for remote monitoring of aquifer depletion. Interferometric Synthetic Aperture Radar (InSAR) analyses of ground level subsidence can account for a significant portion of mass loss observed in GRACE data and provide information on point-sources of overdraft. This study summed one water-year of GRACE monthly mass change grids and delineated regions with negative water storage anomalies for further InSAR analyses. Magnitude of water-storage anomalies observed by GRACE were compared to InSAR-derived minimum volumetric changes in aquifer storage capacity as a result of measurable compaction at the surface. Four major aquifers were selected within regions where GRACE observed a net decrease in water storage (Central Valley, California; Mekong Delta, Vietnam; West Bank, occupied Palestinian Territory; and the Indus Basin, South Asia). Interferogram imagery of the extent and magnitude of subsidence within study regions provided estimates for net minimum volume of groundwater extracted between image acquisitions. These volumetric estimates were compared to GRACE mass change grids to resolve a percent contribution of mass change observed by GRACE likely due to groundwater overdraft. Interferograms revealed characteristic cones of depression within regions of net mass loss observed by GRACE, suggesting point-source locations of groundwater overdraft and demonstrating forensic potential for the use of InSAR and GRACE data in remote monitoring of aquifer depletion. Paired GRACE and InSAR analyses offer a technique to increase the spatial and temporal resolution of remote applications for monitoring groundwater overdraft in addition to providing a novel parameter - measurable vertical deformation at the surface - to global groundwater models.

  9. Grace and Courtesy: Empowering Children, Liberating Adults

    Science.gov (United States)

    Sackett, Ginni

    2015-01-01

    Ginni Sackett delves into the many implications of grace and courtesy, from social relations and the basis of community to respect for the child's personality. Her point of departure is modern social living with grace and dignity. Hers is an exploration over two generations of seeing grace and courtesy as a comprehensive social view that is the…

  10. Seismic Safety Program: Ground motion and structural response

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    In 1964, John A. Blume & Associates Research Division (Blume) began a broad-range structural response program to assist the Nevada Operations Office of the US Atomic Energy Commission (AEC) in ensuring the continued safe conduct of underground nuclear detonation testing at the Nevada Test Site (NTS) and elsewhere. Blume`s long experience in earthquake engineering provided a general basis for the program, but much more specialized knowledge was required for the AEC`s purposes. Over the next 24 years Blume conducted a major research program to provide essential understanding of the detailed nature of the response of structures to dynamic loads such as those imposed by seismic wave propagation. The program`s results have been embodied in a prediction technology which has served to provide reliable advanced knowledge of the probable effects of seismic ground motion on all kinds of structures, for use in earthquake engineering and in building codes as well as for the continuing needs of the US Department of Energy`s Nevada Operations Office (DOE/NV). This report is primarily an accounting of the Blume work, beginning with the setting in 1964 and the perception of the program needs as envisioned by Dr. John A. Blume. Subsequent chapters describe the structural response program in detail and the structural prediction procedures which resulted; the intensive data acquisition program which, as is discussed at some length, relied heavily on the contributions of other consultant-contractors in the DOE/NV Seismic Safety Support Program; laboratory and field studies to provide data on building elements and structures subjected to dynamic loads from sources ranging from testing machines to earthquakes; structural response activities undertaken for testing at the NTS and for off-NTS underground nuclear detonations; and concluding with an account of corollary studies including effects of natural forces and of related studies on building response.

  11. Rainfall Product Evaluation for the TRMM Ground Validation Program

    Science.gov (United States)

    Amitai, E.; Wolff, D. B.; Robinson, M.; Silberstein, D. S.; Marks, D. A.; Kulie, M. S.; Fisher, B.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Evaluation of the Tropical Rainfall Measuring Mission (TRMM) satellite observations is conducted through a comprehensive Ground Validation (GV) Program. Standardized instantaneous and monthly rainfall products are routinely generated using quality-controlled ground based radar data from four primary GV sites. As part of the TRMM GV program, effort is being made to evaluate these GV products and to determine the uncertainties of the rainfall estimates. The evaluation effort is based on comparison to rain gauge data. The variance between the gauge measurement and the true averaged rain amount within the radar pixel is a limiting factor in the evaluation process. While monthly estimates are relatively simple to evaluate, the evaluation of the instantaneous products are much more of a challenge. Scattegrams of point comparisons between radar and rain gauges are extremely noisy for several reasons (e.g. sample volume discrepancies, timing and navigation mismatches, variability of Z(sub e)-R relationships), and therefore useless for evaluating the estimates. Several alternative methods, such as the analysis of the distribution of rain volume by rain rate as derived from gauge intensities and from reflectivities above the gauge network will be presented. Alternative procedures to increase the accuracy of the estimates and to reduce their uncertainties also will be discussed.

  12. Kantian Grace as Ethical Gymnastics

    NARCIS (Netherlands)

    Vanden Auweele, Dennis

    2017-01-01

    Kant’s concept of grace in Religion within the Bounds of Mere Reason is a difficult topic, exegetically speaking. Obviously enough, Kant subscribes positively to a notion of divine assistance. This appears awkward given his rationalist ethics rooted in personal autonomy. This has given cause to

  13. Measuring Earth: Current status of the GRACE Follow-On Laser Ranging Interferometer

    Science.gov (United States)

    Schütze, Daniel; LRI Team

    2016-05-01

    The GRACE mission that was launched in 2002 has impressively proven the feasibility of low-orbit satellite-to-satellite tracking for Earth gravity observations. Especially mass transport related to Earth's hydrological system could be well resolved both spatially and temporally. This allows to study processes such as polar ice sheet decline and ground water depletion in great detail. Owing to GRACE's success, NASA and GFZ will launch the successor mission GRACE Follow-On in 2017. In addition to the microwave ranging system, GRACE Follow-On will be the first mission to use a Laser Ranging Interferometer as technology demonstrator to track intersatellite distance changes with unprecedented precision. This new ranging device inherits some of the technologies which have been developed for the future spaceborne gravitational wave detector LISA. I will present the architecture of the Laser Ranging Interferometer, point out similarities and differences to LISA, and conclude with the current status of the flight hardware production.

  14. The GPM Ground Validation Program: Pre to Post-Launch

    Science.gov (United States)

    Petersen, W. A.

    2014-12-01

    NASA GPM Ground Validation (GV) activities have transitioned from the pre to post-launch era. Prior to launch direct validation networks and associated partner institutions were identified world-wide, covering a plethora of precipitation regimes. In the U.S. direct GV efforts focused on use of new operational products such as the NOAA Multi-Radar Multi-Sensor suite (MRMS) for TRMM validation and GPM radiometer algorithm database development. In the post-launch, MRMS products including precipitation rate, types and data quality are being routinely generated to facilitate statistical GV of instantaneous and merged GPM products. To assess precipitation column impacts on product uncertainties, range-gate to pixel-level validation of both Dual-Frequency Precipitation Radar (DPR) and GPM microwave imager data are performed using GPM Validation Network (VN) ground radar and satellite data processing software. VN software ingests quality-controlled volumetric radar datasets and geo-matches those data to coincident DPR and radiometer level-II data. When combined MRMS and VN datasets enable more comprehensive interpretation of ground-satellite estimation uncertainties. To support physical validation efforts eight (one) field campaigns have been conducted in the pre (post) launch era. The campaigns span regimes from northern latitude cold-season snow to warm tropical rain. Most recently the Integrated Precipitation and Hydrology Experiment (IPHEx) took place in the mountains of North Carolina and involved combined airborne and ground-based measurements of orographic precipitation and hydrologic processes underneath the GPM Core satellite. One more U.S. GV field campaign (OLYMPEX) is planned for late 2015 and will address cold-season precipitation estimation, process and hydrology in the orographic and oceanic domains of western Washington State. Finally, continuous direct and physical validation measurements are also being conducted at the NASA Wallops Flight Facility multi

  15. Reducing errors in the GRACE gravity solutions using regularization

    Science.gov (United States)

    Save, Himanshu; Bettadpur, Srinivas; Tapley, Byron D.

    2012-09-01

    The nature of the gravity field inverse problem amplifies the noise in the GRACE data, which creeps into the mid and high degree and order harmonic coefficients of the Earth's monthly gravity fields provided by GRACE. Due to the use of imperfect background models and data noise, these errors are manifested as north-south striping in the monthly global maps of equivalent water heights. In order to reduce these errors, this study investigates the use of the L-curve method with Tikhonov regularization. L-curve is a popular aid for determining a suitable value of the regularization parameter when solving linear discrete ill-posed problems using Tikhonov regularization. However, the computational effort required to determine the L-curve is prohibitively high for a large-scale problem like GRACE. This study implements a parameter-choice method, using Lanczos bidiagonalization which is a computationally inexpensive approximation to L-curve. Lanczos bidiagonalization is implemented with orthogonal transformation in a parallel computing environment and projects a large estimation problem on a problem of the size of about 2 orders of magnitude smaller for computing the regularization parameter. Errors in the GRACE solution time series have certain characteristics that vary depending on the ground track coverage of the solutions. These errors increase with increasing degree and order. In addition, certain resonant and near-resonant harmonic coefficients have higher errors as compared with the other coefficients. Using the knowledge of these characteristics, this study designs a regularization matrix that provides a constraint on the geopotential coefficients as a function of its degree and order. This regularization matrix is then used to compute the appropriate regularization parameter for each monthly solution. A 7-year time-series of the candidate regularized solutions (Mar 2003-Feb 2010) show markedly reduced error stripes compared with the unconstrained GRACE release 4

  16. Grace and Courtesy for the Whole School

    Science.gov (United States)

    Cobb, Mary Lou

    2015-01-01

    Mary Lou Cobb gives a framework from a very practical point of view, leaning on the aspects of grace and courtesy that are fundamental and arise out of a Montessori administrative point of view. Her examples are pragmatic, such as the grace and courtesy of a greeting, of movement, as a whole-school culture, and the right use of language. She calls…

  17. Living Grace and Courtesy in the Primary

    Science.gov (United States)

    Soholt, Polli

    2015-01-01

    Polli Soholt looks at grace and courtesy from the 3-6 classroom perspective with clear theory explanations as they pertain to the larger classroom culture. She discusses the link between older and young children and the presence of the teacher as a model for grace and takes a brief look to neural science for proof of the existence of social…

  18. Grace and Courtesy in the Elementary Community

    Science.gov (United States)

    Huneke-Stone, Elise

    2015-01-01

    Don't be fooled by Elise Huneke-Stone's disarming beginning where she implies that grace and courtesy is not normally associated with the elementary. She goes on to elaborate that grace and courtesy is indeed everywhere: in project-based learning, understanding of moral precepts, social and intellectual independence, in the utilization of empathy,…

  19. Numerical precision control and GRACE

    International Nuclear Information System (INIS)

    Fujimoto, J.; Hamaguchi, N.; Ishikawa, T.; Kaneko, T.; Morita, H.; Perret-Gallix, D.; Tokura, A.; Shimizu, Y.

    2006-01-01

    The control of the numerical precision of large-scale computations like those generated by the GRACE system for automatic Feynman diagram calculations has become an intrinsic part of those packages. Recently, Hitachi Ltd. has developed in FORTRAN a new library HMLIB for quadruple and octuple precision arithmetic where the number of lost-bits is made available. This library has been tested with success on the 1-loop radiative correction to e + e - ->e + e - τ + τ - . It is shown that the approach followed by HMLIB provides an efficient way to track down the source of numerical significance losses and to deliver high-precision results yet minimizing computing time

  20. Antarctic Ocean Tides from GRACE Intersatellite Tracking Data and Hydrodynamic Assimilation

    Science.gov (United States)

    Erofeeva, S.; Han, S.; Ray, R.; Egbert, G.; Luthcke, S.

    2007-12-01

    Long-wavelength components of the oceanic tides surrounding Antarctica are estimated from over three years of GRACE satellite-to-satellite ranging measurements. An inversion is performed for the major constituents M2, O1, and S2, parameterized as localized average mass anomalies relative to a prior tidal model. Satellite state adjustments are made simultaneously. These long-wavelength anomalies are then assimilated into a high-resolution regional hydrodynamic tidal model. Comparisons to independent "ground truth" data, previously collected by King and Padman, show that assimilation of the GRACE inversions results in improved accuracy, for all three constituents.

  1. Florida's ground water quality monitoring program: background hydrogeochemistry

    OpenAIRE

    Maddox, Gary; Upchurch, Sam; Lloyd, Jacqueline; Scott, Tom

    1992-01-01

    The purpose of this report is to present the results of the initial quantification of background water quality in each of the state's major potable aquifer systems. Results are presented and interpreted in light of the influencing factors which locally and regionally affect ambient ground-water quality. This initial data will serve as a baseline from which future sampling results can be compared. Future sampling of the Network will indicate the extent to which Flori...

  2. 76 FR 10899 - Decision To Evaluate a Petition To Designate a Class of Employees From the W.R. Grace and Company...

    Science.gov (United States)

    2011-02-28

    ... Employees From the W.R. Grace and Company in Curtis, MD, To Be Included in the Special Exposure Cohort... evaluate a petition to designate a class of employees from the W.R. Grace and Company in Curtis, Maryland... Compensation Program Act of 2000. The initial proposed definition for the class being evaluated, subject to...

  3. Earthquake Signal Visible in GRACE Data

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure1 This figure shows the effect of the December 2004 great Sumatra earthquake on the Earth's gravity field as observed by GRACE. The signal is expressed in terms of the relative acceleration of the two GRACE satellites, in this case a few nanometers per second squared, or about 1 billionth of the acceleration we experience everyday at the Earth's surface.GRACE observations show comparable signals in the region of the earthquake. Other natural variations are also apparent in the expected places, whereas no other significant change would be expected in the region of the earthquake GRACE, twin satellites launched in March 2002, are making detailed measurements of Earth's gravity field which will lead to discoveries about gravity and Earth's natural systems. These discoveries could have far-reaching benefits to society and the world's population.

  4. 77 FR 73452 - Grace Period Study

    Science.gov (United States)

    2012-12-10

    ... survey may be distributed in waves for convenience. The Grace Period Study survey will be an electronic... information that is used for sampling purposes will be maintained in a separate file from the quantitative...

  5. Progress towards CSR RL06 GRACE gravity solutions

    Science.gov (United States)

    Save, Himanshu

    2017-04-01

    The GRACE project plans to re-processes the GRACE mission data in order to be consistent with the first gravity products released by the GRACE-FO project. The next generation Release-06 (RL06) gravity products from GRACE will include the improvements in GRACE Level-1 data products, background gravity models and the processing methodology. This paper will outline the planned improvements for CSR - RL06 and discuss the preliminary results. This paper will discuss the evolution of the quality of the GRACE solutions, especially over the past few years. We will also discuss the possible challenges we may face in connecting/extending the measurements of mass fluxes from the GRACE era to the GRACE-FO era due quality of the GRACE solutions from recent years.

  6. The Light and the Grace: Christian Metaphors

    Directory of Open Access Journals (Sweden)

    Iacob COMAN

    2011-01-01

    Full Text Available Our present study continues to provide guidance and meaning for those who are open and have the courage to ask the kind of questions superior to reason. The acceptance of unreasonable realities expresses sometimes the portrait of a non-modern and superstitious man, a portrait dismantled by the contemporary science in order to get the assurance of control over the material and spiritual reality around us. However, the acceptance of unreasonable realities, born by the reason’s questions, expresses in other circumstances the access to super-reason and super-faith. The Light and the Grace from super-existence toward the human nature, and the implications these have, as a divine communication method and metaphors, and as a call to dialogic sharing with the Divine, are the objects of our present study. Super-reason and super-faith can and must characterize also the modern man. The Light and the Grace express both the cause and the means; God who is Light and Grace does communicate Himself in a salvific manner through Light and Grace, and we, as destinations of Light and of Grace can communicate ourselves as Light and Grace to our neighbors.

  7. Ground-Based Photometric Measurements HAES Program Support.

    Science.gov (United States)

    1979-01-31

    A3, A-, E, F (J) Spatial structure of optical irregularities from F (K) Auroral electric fields from G, (BI, 132) ( L ) Pederson and Hall...investigator on this program was Mr. R. D. Sears. Also contributing significantly to the program were D. R. Hillendahl and G. Rogers . We acknowledge the...WBM experiment 57 23 Plot of height-integrated Pederson conductivities versus horizontal distance from Chatanika zenith for WBM experiment 58 24

  8. Construction Management Program Builds Financial Development from the Ground up

    Science.gov (United States)

    Nobe, Michael D.; Shuler, Scott; Grosse, Larry

    2007-01-01

    Recent economic and legislative changes have hit higher education hard and threaten the financial viability of many educational programs nationwide. With state support dwindling to less than 10 percent in some cases, institutions across the nation face a financial crisis. Many strategies have been explored and implemented, from campaigns to…

  9. Building a visionary astrophysics program from the ground up

    Science.gov (United States)

    Mathews, Geoffrey S.; Barnes, Joshua Edward; Coleman, Paul; Gal, Roy R.; Meech, Karen J.; Mendez, Roberto Hugo; Nassir, Michael A.; Sanders, David B.

    2015-08-01

    The University of Hawaii’s Institute for Astronomy is in the process of implementing a new Bachelor of Science in Astrophysics at UH Manoa. This requires a significant adjustment in the role of the IfA, which has long been at the forefront of modern astronomy in Hawaii and is now broadening its educational mission. The IfA’s history of excellence in research and access to observational resources are expected to draw students from around the nation and the world. These factors have inspired our programmatic focus culminating in a senior year research experience. We expect that the program will produce many undergraduate astrophysics majors, making it an ideal testbed to apply modern theories of learning to the teaching of astrophysics. We have explicitly designed the major around three pillars: physical theory, the application of physics to astrophysical phenomena, and the development of core observational astronomy skills. We describe our cooperative approach to developing a program-level curriculum map of key concepts and skills, as well as descriptors of student success throughout the program. These are central tools for course design, program assessment, and professional development.

  10. Status of CSR RL06 GRACE reprocessing and preliminary results

    Science.gov (United States)

    Save, H.

    2017-12-01

    The GRACE project plans to re-processes the GRACE mission data in order to be consistent with the first gravity products released by the GRACE-FO project. The RL06 reprocessing will harmonize the GRACE time-series with the first release of GRACE-FO. This paper catalogues the changes in the upcoming RL06 release and discusses the quality improvements as compared to the current RL05 release. The processing and parameterization changes as compared to the current release are also discussed. This paper discusses the evolution of the quality of the GRACE solutions and characterize the errors over the past few years. The possible challenges associated with connecting the GRACE time series with that from GRACE-FO are also discussed.

  11. Development of a package program for estimating ground level concentrations of radioactive gases

    International Nuclear Information System (INIS)

    Nilkamhang, W.

    1986-01-01

    A package program for estimating ground level concentration of radioactive gas from elevate release was develop for use on IBM P C microcomputer. The main program, GAMMA PLUME NT10, is based on the well known VALLEY MODEL which is a Fortran computer code intended for mainframe computers. Other two options were added, namely, calculation of radioactive gas ground level concentration in Ci/m 3 and dose equivalent rate in mren/hr. In addition, a menu program and editor program were developed to render the program easier to use since the option could be readily selected and the input data could be easily modified as required through the keyboard. The accuracy and reliability of the program is almost identical to the mainframe. Ground level concentration of radioactive radon gas due to ore program processing in the nuclear chemistry laboratory of the Department of Nuclear Technology was estimated. In processing radioactive ore at a rate of 2 kg/day, about 35 p Ci/s of radioactive gas was released from a 14 m stack. When meteorological data of Don Muang (average for 5 years 1978-1982) were used maximum ground level concentration and the dose equivalent rate were found to be 0.00094 p Ci/m 3 and 5.0 x 10 -10 mrem/hr respectively. The processing time required for the above problem was about 7 minutes for any case of source on IBM P C which was acceptable for a computer of this class

  12. GRace: a MATLAB-based application for fitting the discrimination-association model.

    Science.gov (United States)

    Stefanutti, Luca; Vianello, Michelangelo; Anselmi, Pasquale; Robusto, Egidio

    2014-10-28

    The Implicit Association Test (IAT) is a computerized two-choice discrimination task in which stimuli have to be categorized as belonging to target categories or attribute categories by pressing, as quickly and accurately as possible, one of two response keys. The discrimination association model has been recently proposed for the analysis of reaction time and accuracy of an individual respondent to the IAT. The model disentangles the influences of three qualitatively different components on the responses to the IAT: stimuli discrimination, automatic association, and termination criterion. The article presents General Race (GRace), a MATLAB-based application for fitting the discrimination association model to IAT data. GRace has been developed for Windows as a standalone application. It is user-friendly and does not require any programming experience. The use of GRace is illustrated on the data of a Coca Cola-Pepsi Cola IAT, and the results of the analysis are interpreted and discussed.

  13. Grace and Courtesy across the Planes of Development

    Science.gov (United States)

    Ludick, Pat

    2015-01-01

    Pat Ludick's commentary on grace and courtesy is established by a philosophical orientation to development: Grace is oriented to the life of the interior that is consciousness and being, and courtesy moves outward to daily living where civility reflects on success with human interactions. Pat's projected grace and courtesy across the planes is…

  14. Study of Extreme Weather Hazards Using GRACE

    Science.gov (United States)

    Zhang, Y.; Shum, C. K.; Shang, K.; Guo, J.; Schwartz, F. W.; Akyılmaz, O.; Feng, W.; Forootan, E.; LIU, G.; Zhong, M.

    2017-12-01

    Extreme weather events significantly affect humans and economics in the region. Synoptic and timely observations of these abrupt meteoro-hydrological hazards would benefit disaster management and improve storm forecasting. Contemporary processing of the Gravity Recovery and Climate Experiment (GRACE) twin-satellite data at monthly sampling would miss or under-sample abrupt events such as large ice storms with durations much shorter than a month. Here, we employ the energy balance approach processing GRACE Level 1 data, which is flexible to allow sub-monthly solutions at daily sampling covering the genesis and evolution of large winter storms. We studied the 2008 Southeast China snow and ice storm, which lasted from mid-January to mid-February, and affected 21 out of China's 34 provinces with heavy snows, ice and freezing rains, caused extensive damage and transportation disruption, displaced nearly 1.7 million people, and claimed 129 lives. We also investigated the devastating North America blizzard which occurred during late January through mid-February 2010. The massive accumulations of snow and ice in both storms slightly changed the gravity field of the Earth, and were sensitive to the GRACE satellite measurements, manifested as transient terrestrial water storage (TWS) change. We compared our solutions with other available high temporal frequency GRACE solutions. The GRACE observed total storage change for both storms are in good agreement with in situ precipitation measurements, and with GRACE observations clearly show the complex genesis, decline, strengthening and melting phases depicting the detailed evolution of these example large snow storms.

  15. Towards Improved Snow Water Equivalent Estimation via GRACE Assimilation

    Science.gov (United States)

    Forman, Bart; Reichle, Rofl; Rodell, Matt

    2011-01-01

    Passive microwave (e.g. AMSR-E) and visible spectrum (e.g. MODIS) measurements of snow states have been used in conjunction with land surface models to better characterize snow pack states, most notably snow water equivalent (SWE). However, both types of measurements have limitations. AMSR-E, for example, suffers a loss of information in deep/wet snow packs. Similarly, MODIS suffers a loss of temporal correlation information beyond the initial accumulation and final ablation phases of the snow season. Gravimetric measurements, on the other hand, do not suffer from these limitations. In this study, gravimetric measurements from the Gravity Recovery and Climate Experiment (GRACE) mission are used in a land surface model data assimilation (DA) framework to better characterize SWE in the Mackenzie River basin located in northern Canada. Comparisons are made against independent, ground-based SWE observations, state-of-the-art modeled SWE estimates, and independent, ground-based river discharge observations. Preliminary results suggest improved SWE estimates, including improved timing of the subsequent ablation and runoff of the snow pack. Additionally, use of the DA procedure can add vertical and horizontal resolution to the coarse-scale GRACE measurements as well as effectively downscale the measurements in time. Such findings offer the potential for better understanding of the hydrologic cycle in snow-dominated basins located in remote regions of the globe where ground-based observation collection if difficult, if not impossible. This information could ultimately lead to improved freshwater resource management in communities dependent on snow melt as well as a reduction in the uncertainty of river discharge into the Arctic Ocean.

  16. Ground Truth Studies - A hands-on environmental science program for students, grades K-12

    Science.gov (United States)

    Katzenberger, John; Chappell, Charles R.

    1992-01-01

    The paper discusses the background and the objectives of the Ground Truth Studies (GTSs), an activity-based teaching program which integrates local environmental studies with global change topics, utilizing remotely sensed earth imagery. Special attention is given to the five key concepts around which the GTS programs are organized, the pilot program, the initial pilot study evaluation, and the GTS Handbook. The GTS Handbook contains a primer on global change and remote sensing, aerial and satellite images, student activities, glossary, and an appendix of reference material. Also described is a K-12 teacher training model. International participation in the program is to be initiated during the 1992-1993 school year.

  17. Ocean tides in GRACE monthly averaged gravity fields

    DEFF Research Database (Denmark)

    Knudsen, Per

    2003-01-01

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

  18. From the ground up: building a minimally invasive aortic valve surgery program

    OpenAIRE

    Nguyen, Tom C.; Lamelas, Joseph

    2015-01-01

    Minimally invasive aortic valve replacement (MIAVR) is associated with numerous advantages including improved patient satisfaction, cosmesis, decreased transfusion requirements, and cost-effectiveness. Despite these advantages, little information exists on how to build a MIAVR program from the ground up. The steps to build a MIAVR program include compiling a multi-disciplinary team composed of surgeons, cardiologists, anesthesiologists, perfusionists, operating room (OR) technicians, and nurs...

  19. Kennedy Space Center: Constellation Program Electrical Ground Support Equipment Research and Development

    Science.gov (United States)

    McCoy, Keegan

    2010-01-01

    The Kennedy Space Center (KSC) is NASA's spaceport, launching rockets into space and leading important human spaceflight research. This spring semester, I worked at KSC on Constellation Program electrical ground support equipment through NASA's Undergraduate Student Research Program (USRP). This report includes a discussion of NASA, KSC, and my individual research project. An analysis of Penn State's preparation of me for an internship and my overall impressions of the Penn State and NASA internship experience conclude the report.

  20. Identifying Barriers in Implementing Outcomes-Based Assessment Program Review: A Grounded Theory Analysis

    Science.gov (United States)

    Bresciani, Marilee J.

    2011-01-01

    The purpose of this grounded theory study was to identify the typical barriers encountered by faculty and administrators when implementing outcomes-based assessment program review. An analysis of interviews with faculty and administrators at nine institutions revealed a theory that faculty and administrators' promotion, tenure (if applicable),…

  1. Ground beetle (Coleoptera: Carabidae) assemblages in the Conservation Reserve Program crop rotation systems in Interior Alaska

    Science.gov (United States)

    Adult ground beetles (Coleoptera: Carabidae) abundance and diversity were documented on Conservation Research Program (CRP) agricultural lands in Delta Junction, Alaska (64ºN, 145º W). Twenty species were documented based on a total sample of 6,116 specimens collected during 2006 and 2007. Two speci...

  2. A nonlinear programming approach to lower bounds for the ground-state energy of helium

    International Nuclear Information System (INIS)

    Porras, I.; Feldmann, D.M.; King, F.W.

    1999-01-01

    Lower-bound estimates for the ground-state energy of the helium atom are determined using nonlinear programming techniques. Optimized lower bounds are determined for single-particle, radially correlated, and general correlated wave functions. The local nature of the method employed makes it a very severe test of the accuracy of the wave function

  3. Glacial Isostatic Adjustment as a Source of Noise for the Interpretation of GRACE Data

    Science.gov (United States)

    Wahr, J.; Velicogna, I.; Paulson, A.

    2009-05-01

    Viscoelastic relaxation in the Earth's mantle caused by wide-spread deglaciation following the last glacial maximum (LGM), can appear as a secular trend in measurements of the Earth's time-variable gravity field. The presence of this trend can provide an opportunity to use gravity observations to constrain models of the glacial isostatic adjustment (GIA) process. But it can also be a nuisance for people who are using the gravity observations to learn about other things. Gravity observations, whether from satellites or from ground-based gravimeters, can not distinguish between the gravitational effects of water/snow/ice variations on or near the surface, and those caused by density variations deep within the mantle. Unmodeled or mismodeled GIA signals can sometimes make it difficult to use gravity observations to learn about secular changes in water/snow/ice from such places as northern Canada, Scandinavia, Antarctica, and Greenland: places where there was considerable long-term deglaciation following the LGM. These issues have become particularly important since the 2002 launch of the GRACE gravity satellite mission. GIA signals in northern Canada and Scandinavia are clearly evident in the GRACE data. But the presence of GIA signals in these and other regions has sometimes caused problems for long-term hydrological and, especially, cryospheric studies with GRACE. GIA model errors, for example, are by far the largest source of uncertainty when using GRACE to estimate present-day thinning rates of the Antarctic ice sheet. This talk will discuss the contributions of the GIA signal to GRACE time-variable gravity measurements; partly as an opportunity to study the GIA process, but mostly as a source of uncertainty for other applications.

  4. Recovery Act: Finite Volume Based Computer Program for Ground Source Heat Pump Systems

    Energy Technology Data Exchange (ETDEWEB)

    James A Menart, Professor

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled Finite Volume Based Computer Program for Ground Source Heat Pump Systems. The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump. The

  5. Finite Volume Based Computer Program for Ground Source Heat Pump System

    Energy Technology Data Exchange (ETDEWEB)

    Menart, James A. [Wright State University

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled ?Finite Volume Based Computer Program for Ground Source Heat Pump Systems.? The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump

  6. Using Enhanced Grace Water Storage Data to Improve Drought Detection by the U.S. and North American Drought Monitors

    Science.gov (United States)

    Houborg, Rasmus; Rodell, Matthew; Lawrimore, Jay; Li, Bailing; Reichle, Rolf; Heim, Richard; Rosencrans, Matthew; Tinker, Rich; Famiglietti, James S.; Svoboda, Mark; hide

    2011-01-01

    NASA's Gravity Recovery and Climate Experiment (GRACE) satellites measure time variations of the Earth's gravity field enabling reliable detection of spatio-temporal variations in total terrestrial water storage (TWS), including groundwater. The U.S. and North American Drought Monitors rely heavily on precipitation indices and do not currently incorporate systematic observations of deep soil moisture and groundwater storage conditions. Thus GRACE has great potential to improve the Drought Monitors by filling this observational gap. GRACE TWS data were assimilating into the Catchment Land Surface Model using an ensemble Kalman smoother enabling spatial and temporal downscaling and vertical decomposition into soil moisture and groundwater components. The Drought Monitors combine several short- and long-term drought indicators expressed in percentiles as a reference to their historical frequency of occurrence. To be consistent, we generated a climatology of estimated soil moisture and ground water based on a 60-year Catchment model simulation, which was used to convert seven years of GRACE assimilated fields into drought indicator percentiles. At this stage we provide a preliminary evaluation of the GRACE assimilated moisture and indicator fields.

  7. Further results on super graceful labeling of graphs

    Directory of Open Access Journals (Sweden)

    Gee-Choon Lau

    2016-08-01

    Full Text Available Let G=(V(G,E(G be a simple, finite and undirected graph of order p and size q. A bijection f:V(G∪E(G→{k,k+1,k+2,…,k+p+q−1} such that f(uv=|f(u−f(v| for every edge uv∈E(G is said to be a k-super graceful labeling of G. We say G is k-super graceful if it admits a k-super graceful labeling. For k=1, the function f is called a super graceful labeling and a graph is super graceful if it admits a super graceful labeling. In this paper, we study the super gracefulness of complete graph, the disjoint union of certain star graphs, the complete tripartite graphs K(1,1,n, and certain families of trees. We also present four methods of constructing new super graceful graphs. In particular, all trees of order at most 7 are super graceful. We conjecture that all trees are super graceful.

  8. Groundwater depletion in Central Mexico: Use of GRACE and InSAR to support water resources management

    Science.gov (United States)

    Castellazzi, Pascal; Martel, Richard; Rivera, Alfonso; Huang, Jianliang; Pavlic, Goran; Calderhead, Angus I.; Chaussard, Estelle; Garfias, Jaime; Salas, Javier

    2016-08-01

    Groundwater deficits occur in several areas of Central Mexico, where water resource assessment is limited by the availability and reliability of field data. In this context, GRACE and InSAR are used to remotely assess groundwater storage loss in one of Mexico's most important watersheds in terms of size and economic activity: the Lerma-Santiago-Pacifico (LSP). In situ data and Land Surface Models are used to subtract soil moisture and surface water storage changes from the total water storage change measured by GRACE satellites. As a result, groundwater mass change time-series are obtained for a 12 years period. ALOS-PALSAR images acquired from 2007 to 2011 were processed using the SBAS-InSAR algorithm to reveal areas subject to ground motion related to groundwater over-exploitation. In the perspective of providing guidance for groundwater management, GRACE and InSAR observations are compared with official water budgets and field observations. InSAR-derived subsidence mapping generally agrees well with official water budgets, and shows that deficits occur mainly in cities and irrigated agricultural areas. GRACE does not entirely detect the significant groundwater losses largely reported by official water budgets, literature and InSAR observations. The difference is interpreted as returns of wastewater to the groundwater flow systems, which limits the watershed scale groundwater depletion but suggests major impacts on groundwater quality. This phenomenon is enhanced by ground fracturing as noticed in the field. Studying the fate of the extracted groundwater is essential when comparing GRACE data with higher resolution observations, and particularly in the perspective of further InSAR/GRACE combination in hydrogeology.

  9. Integrating Enhanced Grace Terrestrial Water Storage Data Into the U.S. and North American Drought Monitors

    Science.gov (United States)

    Housborg, Rasmus; Rodell, Matthew

    2010-01-01

    NASA's Gravity Recovery and Climate Experiment (GRACE) satellites measure time variations nf the Earth's gravity field enabling reliable detection of spatio-temporal variations in total terrestrial water storage (TWS), including ground water. The U.S. and North American Drought Monitors are two of the premier drought monitoring products available to decision-makers for assessing and minimizing drought impacts, but they rely heavily on precipitation indices and do not currently incorporate systematic observations of deep soil moisture and groundwater storage conditions. Thus GRACE has great potential to improve the Drought Monitors hy filling this observational gap. Horizontal, vertical and temporal disaggregation of the coarse-resolution GRACE TWS data has been accomplished by assimilating GRACE TWS anomalies into the Catchment Land Surface Model using ensemble Kalman smoother. The Drought Monitors combine several short-term and long-term drought indices and indicators expressed in percentiles as a reference to their historical frequency of occurrence for the location and time of year in question. To be consistent, we are in the process of generating a climatology of estimated soil moisture and ground water based on m 60-year Catchment model simulation which will subsequently be used to convert seven years of GRACE assimilated fields into soil moisture and groundwater percentiles. for systematic incorporation into the objective blends that constitute Drought Monitor baselines. At this stage we provide a preliminary evaluation of GRACE assimilated Catchment model output against independent datasets including soil moisture observations from Aqua AMSR-E and groundwater level observations from the U.S. Geological Survey's Groundwater Climate Response Network.

  10. Can GRACE detect winter snows in Japan?

    Science.gov (United States)

    Heki, Kosuke

    2010-05-01

    Current spatial resolution of the GRACE (Gravity Recovery and Climate Experiment) satellites is 300-400 km, and so its hydrological applications have been limited to continents and large islands. The Japanese Islands have width slightly smaller than this spatial resolution, but are known to show large amplitude seasonal changes in surface masses due mainly to winter snow. Such loads are responsible for seasonal crustal deformation observed with GEONET, a dense array of GPS (Global Positioning System) receivers in Japan (Heki, 2001). There is also a dense network of surface meteorological sensors for, e.g. snow depths, atmospheric pressures, etc. Heki (2004) showed that combined effects of surface loads, i.e. snow (predominant), atmosphere, soil moisture, dam impoundment, can explain seasonal crustal deformation observed by GPS to a large extent. The total weight of the winter snow in the Japanese Islands in its peak season may reach ~50 Gt. This is comparable to the annual loss of mountain glaciers in the Asian high mountains (Matsuo & Heki, 2010), and is above the detection level of GRACE. In this study, I use GRACE Level-2 Release-4 data from CSR, Univ. Texas, up to 2009 November, and evaluated seasonal changes in surface loads in and around the Japanese Islands. After applying a 350 km Gaussian filter and a de-striping filter, the peak-to-peak change of the water depth becomes ~4 cm in northern Japan. The maximum value is achieved in February-March. The region of large winter load spans from Hokkaido, Japan, to northeastern Honshu, which roughly coincides with the region of deep snow in Japan. Next I compiled snow depth data from surface meteorological observations, and converted them to loads using time-dependent snow density due to compaction. By applying the same spatial filter as the GRACE data, its spatial pattern becomes similar to the GRACE results. The present study suggests that GRACE is capable of detecting seasonal mass changes in an island arc not

  11. A Dynamic Programming-Based Heuristic for the Shift Design Problem in Airport Ground Handling

    DEFF Research Database (Denmark)

    Clausen, Tommy

    We consider the heterogeneous shift design problem for a workforce with multiple skills, where work shifts are created to cover a given demand as well as possible while minimizing cost and satisfying a flexible set of constraints. We focus mainly on applications within airport ground handling whe...... programming that allows flexibility in modeling the workforce. Parameters allow a planner to determine the level of demand coverage that best fulfills the requirements of the organization. Results are presented from several diverse real-life ground handling instances.......We consider the heterogeneous shift design problem for a workforce with multiple skills, where work shifts are created to cover a given demand as well as possible while minimizing cost and satisfying a flexible set of constraints. We focus mainly on applications within airport ground handling where...

  12. Temperature corrected-calibration of GRACE's accelerometer

    Science.gov (United States)

    Encarnacao, J.; Save, H.; Siemes, C.; Doornbos, E.; Tapley, B. D.

    2017-12-01

    Since April 2011, the thermal control of the accelerometers on board the GRACE satellites has been turned off. The time series of along-track bias clearly show a drastic change in the behaviour of this parameter, while the calibration model has remained unchanged throughout the entire mission lifetime. In an effort to improve the quality of the gravity field models produced at CSR in future mission-long re-processing of GRACE data, we quantify the added value of different calibration strategies. In one approach, the temperature effects that distort the raw accelerometer measurements collected without thermal control are corrected considering the housekeeping temperature readings. In this way, one single calibration strategy can be consistently applied during the whole mission lifetime, since it is valid to thermal the conditions before and after April 2011. Finally, we illustrate that the resulting calibrated accelerations are suitable for neutral thermospheric density studies.

  13. Data Mining for Understanding and Impriving Decision-Making Affecting Ground Delay Programs

    Science.gov (United States)

    Kulkarni, Deepak; Wang, Yao Xun; Sridhar, Banavar

    2013-01-01

    The continuous growth in the demand for air transportation results in an imbalance between airspace capacity and traffic demand. The airspace capacity of a region depends on the ability of the system to maintain safe separation between aircraft in the region. In addition to growing demand, the airspace capacity is severely limited by convective weather. During such conditions, traffic managers at the FAA's Air Traffic Control System Command Center (ATCSCC) and dispatchers at various Airlines' Operations Center (AOC) collaborate to mitigate the demand-capacity imbalance caused by weather. The end result is the implementation of a set of Traffic Flow Management (TFM) initiatives such as ground delay programs, reroute advisories, flow metering, and ground stops. Data Mining is the automated process of analyzing large sets of data and then extracting patterns in the data. Data mining tools are capable of predicting behaviors and future trends, allowing an organization to benefit from past experience in making knowledge-driven decisions. The work reported in this paper is focused on ground delay programs. Data mining algorithms have the potential to develop associations between weather patterns and the corresponding ground delay program responses. If successful, they can be used to improve and standardize TFM decision resulting in better predictability of traffic flows on days with reliable weather forecasts. The approach here seeks to develop a set of data mining and machine learning models and apply them to historical archives of weather observations and forecasts and TFM initiatives to determine the extent to which the theory can predict and explain the observed traffic flow behaviors.

  14. Predictive Models of Duration of Ground Delay Programs in New York Area Airports

    Science.gov (United States)

    Kulkarni, Deepak

    2011-01-01

    Initially planned GDP duration often turns out to be an underestimate or an overestimate of the actual GDP duration. This, in turn, results in avoidable airborne or ground delays in the system. Therefore, better models of actual duration have the potential of reducing delays in the system. The overall objective of this study is to develop such models based on logs of GDPs. In a previous report, we described descriptive models of Ground Delay Programs. These models were defined in terms of initial planned duration and in terms of categorical variables. These descriptive models are good at characterizing the historical errors in planned GDP durations. This paper focuses on developing predictive models of GDP duration. Traffic Management Initiatives (TMI) are logged by Air Traffic Control facilities with The National Traffic Management Log (NTML) which is a single system for automated recoding, coordination, and distribution of relevant information about TMIs throughout the National Airspace System. (Brickman, 2004 Yuditsky, 2007) We use 2008-2009 GDP data from the NTML database for the study reported in this paper. NTML information about a GDP includes the initial specification, possibly one or more revisions, and the cancellation. In the next section, we describe general characteristics of Ground Delay Programs. In the third section, we develop models of actual duration. In the fourth section, we compare predictive performance of these models. The final section is a conclusion.

  15. How youth get engaged: grounded-theory research on motivational development in organized youth programs.

    Science.gov (United States)

    Dawes, Nickki Pearce; Larson, Reed

    2011-01-01

    For youth to benefit from many of the developmental opportunities provided by organized programs, they need to not only attend but become psychologically engaged in program activities. This research was aimed at formulating empirically based grounded theory on the processes through which this engagement develops. Longitudinal interviews were conducted with 100 ethnically diverse youth (ages 14–21) in 10 urban and rural arts and leadership programs. Qualitative analysis focused on narrative accounts from the 44 youth who reported experiencing a positive turning point in their motivation or engagement. For 38 of these youth, this change process involved forming a personal connection. Similar to processes suggested by self-determination theory (Ryan & Deci, 2000), forming a personal connection involved youth's progressive integration of personal goals with the goals of program activities. Youth reported developing a connection to 3 personal goals that linked the self with the activity: learning for the future, developing competence, and pursuing a purpose. The role of purpose for many youth suggests that motivational change can be driven by goals that transcend self-needs. These findings suggest that youth need not enter programs intrinsically engaged--motivation can be fostered--and that programs should be creative in helping youth explore ways to form authentic connections to program activities.

  16. Data Mining for Understanding and Improving Decision-making Affecting Ground Delay Programs

    Science.gov (United States)

    Kulkarni, Deepak; Wang, Yao; Sridhar, Banavar

    2013-01-01

    The continuous growth in the demand for air transportation results in an imbalance between airspace capacity and traffic demand. The airspace capacity of a region depends on the ability of the system to maintain safe separation between aircraft in the region. In addition to growing demand, the airspace capacity is severely limited by convective weather. During such conditions, traffic managers at the FAA's Air Traffic Control System Command Center (ATCSCC) and dispatchers at various Airlines' Operations Center (AOC) collaborate to mitigate the demand-capacity imbalance caused by weather. The end result is the implementation of a set of Traffic Flow Management (TFM) initiatives such as ground delay programs, reroute advisories, flow metering, and ground stops. Data Mining is the automated process of analyzing large sets of data and then extracting patterns in the data. Data mining tools are capable of predicting behaviors and future trends, allowing an organization to benefit from past experience in making knowledge-driven decisions.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    Representatives from countries and regions world-wide who have implemented modern competency-based radiation- or clinical oncology curricula for training medical specialists, met to determine the feasibility and value of an ongoing international collaboration. In this forum, educational leaders...... with similar goals, would provide a valuable vehicle to ensure training program currency, through sharing of resources and expertise, and enhance high quality radiation oncology education. Potential projects for the Global Radiation Oncology Collaboration in Education (GRaCE) were agreed upon...

  18. Results from GRACE/SUSY at one-loop

    Indian Academy of Sciences (India)

    We report the recent development on the SUSY calculations with the help of GRACE system. GRACE/SUSY/1LOOP is the computer code which can generate Feynman diagrams in the MSSM automatically and compute one-loop amplitudes in the numerical way. We present new results of various two-body decay widths ...

  19. High-resolution CSR GRACE RL05 mascons

    Science.gov (United States)

    Save, Himanshu; Bettadpur, Srinivas; Tapley, Byron D.

    2016-10-01

    The determination of the gravity model for the Gravity Recovery and Climate Experiment (GRACE) is susceptible to modeling errors, measurement noise, and observability issues. The ill-posed GRACE estimation problem causes the unconstrained GRACE RL05 solutions to have north-south stripes. We discuss the development of global equal area mascon solutions to improve the GRACE gravity information for the study of Earth surface processes. These regularized mascon solutions are developed with a 1° resolution using Tikhonov regularization in a geodesic grid domain. These solutions are derived from GRACE information only, and no external model or data is used to inform the constraints. The regularization matrix is time variable and will not bias or attenuate future regional signals to some past statistics from GRACE or other models. The resulting Center for Space Research (CSR) mascon solutions have no stripe errors and capture all the signals observed by GRACE within the measurement noise level. The solutions are not tailored for specific applications and are global in nature. This study discusses the solution approach and compares the resulting solutions with postprocessed results from the RL05 spherical harmonic solutions and other global mascon solutions for studies of Arctic ice sheet processes, ocean bottom pressure variation, and land surface total water storage change. This suite of comparisons leads to the conclusion that the mascon solutions presented here are an enhanced representation of the RL05 GRACE solutions and provide accurate surface-based gridded information that can be used without further processing.

  20. From the ground up: building a minimally invasive aortic valve surgery program.

    Science.gov (United States)

    Nguyen, Tom C; Lamelas, Joseph

    2015-03-01

    Minimally invasive aortic valve replacement (MIAVR) is associated with numerous advantages including improved patient satisfaction, cosmesis, decreased transfusion requirements, and cost-effectiveness. Despite these advantages, little information exists on how to build a MIAVR program from the ground up. The steps to build a MIAVR program include compiling a multi-disciplinary team composed of surgeons, cardiologists, anesthesiologists, perfusionists, operating room (OR) technicians, and nurses. Once assembled, this team can then approach hospital administrators to present a cost-benefit analysis of MIAVR, emphasizing the importance of reduced resource utilization in the long-term to offset the initial financial investment that will be required. With hospital approval, training can commence to provide surgeons and other staff with the necessary knowledge and skills in MIAVR procedures and outcomes. Marketing and advertising of the program through the use of social media, educational conferences, grand rounds, and printed media will attract the initial patients. A dedicated website for the program can function as a "virtual lobby" for patients wanting to learn more. Initially, conservative selection criteria of cases that qualify for MIAVR will set the program up for success by avoiding complex co-morbidities and surgical techniques. During the learning curve phase of the program, patient safety should be a priority.

  1. How robotics programs influence young women's career choices : a grounded theory model

    Science.gov (United States)

    Craig, Cecilia Dosh-Bluhm

    The fields of engineering, computer science, and physics have a paucity of women despite decades of intervention by universities and organizations. Women's graduation rates in these fields continue to stagnate, posing a critical problem for society. This qualitative grounded theory (GT) study sought to understand how robotics programs influenced young women's career decisions and the program's effect on engineering, physics, and computer science career interests. To test this, a study was mounted to explore how the FIRST (For Inspiration and Recognition of Science and Technology) Robotics Competition (FRC) program influenced young women's college major and career choices. Career theories suggested that experiential programs coupled with supportive relationships strongly influence career decisions, especially for science, technology, engineering, and mathematics careers. The study explored how and when young women made career decisions and how the experiential program and! its mentors and role models influenced career choice. Online focus groups and interviews (online and face-to-face) with 10 female FRC alumnae and GT processes (inductive analysis, open coding, categorizations using mind maps and content clouds) were used to generate a general systems theory style model of the career decision process for these young women. The study identified gender stereotypes and other career obstacles for women. The study's conclusions include recommendations to foster connections to real-world challenges, to develop training programs for mentors, and to nurture social cohesion, a mostly untapped area. Implementing these recommendations could help grow a critical mass of women in engineering, physics, and computer science careers, a social change worth pursuing.

  2. Improvements in GRACE Gravity Fields Using Regularization

    Science.gov (United States)

    Save, H.; Bettadpur, S.; Tapley, B. D.

    2008-12-01

    The unconstrained global gravity field models derived from GRACE are susceptible to systematic errors that show up as broad "stripes" aligned in a North-South direction on the global maps of mass flux. These errors are believed to be a consequence of both systematic and random errors in the data that are amplified by the nature of the gravity field inverse problem. These errors impede scientific exploitation of the GRACE data products, and limit the realizable spatial resolution of the GRACE global gravity fields in certain regions. We use regularization techniques to reduce these "stripe" errors in the gravity field products. The regularization criteria are designed such that there is no attenuation of the signal and that the solutions fit the observations as well as an unconstrained solution. We have used a computationally inexpensive method, normally referred to as "L-ribbon", to find the regularization parameter. This paper discusses the characteristics and statistics of a 5-year time-series of regularized gravity field solutions. The solutions show markedly reduced stripes, are of uniformly good quality over time, and leave little or no systematic observation residuals, which is a frequent consequence of signal suppression from regularization. Up to degree 14, the signal in regularized solution shows correlation greater than 0.8 with the un-regularized CSR Release-04 solutions. Signals from large-amplitude and small-spatial extent events - such as the Great Sumatra Andaman Earthquake of 2004 - are visible in the global solutions without using special post-facto error reduction techniques employed previously in the literature. Hydrological signals as small as 5 cm water-layer equivalent in the small river basins, like Indus and Nile for example, are clearly evident, in contrast to noisy estimates from RL04. The residual variability over the oceans relative to a seasonal fit is small except at higher latitudes, and is evident without the need for de-striping or

  3. GRACE, time-varying gravity, Earth system dynamics and climate change

    Science.gov (United States)

    Wouters, B.; Bonin, J. A.; Chambers, D. P.; Riva, R. E. M.; Sasgen, I.; Wahr, J.

    2014-11-01

    Continuous observations of temporal variations in the Earth's gravity field have recently become available at an unprecedented resolution of a few hundreds of kilometers. The gravity field is a product of the Earth's mass distribution, and these data—provided by the satellites of the Gravity Recovery And Climate Experiment (GRACE)—can be used to study the exchange of mass both within the Earth and at its surface. Since the launch of the mission in 2002, GRACE data has evolved from being an experimental measurement needing validation from ground truth, to a respected tool for Earth scientists representing a fixed bound on the total change and is now an important tool to help unravel the complex dynamics of the Earth system and climate change. In this review, we present the mission concept and its theoretical background, discuss the data and give an overview of the major advances GRACE has provided in Earth science, with a focus on hydrology, solid Earth sciences, glaciology and oceanography.

  4. Estimating Antarctica land topography from GRACE gravity and ICESat altimetry data

    Science.gov (United States)

    Wu, I.; Chao, B. F.; Chen, Y.

    2009-12-01

    We propose a new method combining GRACE (Gravity Recovery and Climate Experiment) gravity and ICESat (Ice, Cloud, and land Elevation Satellite) altimetry data to estimate the land topography for Antarctica. Antarctica is the fifth-largest continent in the world and about 98% of Antarctica is covered by ice, where in-situ measurements are difficult. Some experimental airborne radar and ground-based radar data have revealed very limited land topography beneath heavy ice sheet. To estimate the land topography for the full coverage of Antarctica, we combine GRACE data that indicate the mass distribution, with data of ICESat laser altimetry that provide high-resolution mapping of ice topography. Our approach is actually based on some geological constraints: assuming uniform densities of the land and ice considering the Airy-type isostasy. In the beginning we construct an initial model for the ice thickness and land topography based on the BEDMAP ice thickness and ICESat data. Thereafter we forward compute the model’s gravity field and compare with the GRACE observed data. Our initial model undergoes the adjustments to improve the fit between modeled results and the observed data. Final examination is done by comparing our results with previous but sparse observations of ice thickness to reconfirm the reliability of our results. As the gravitational inversion problem is non-unique, our estimating result is just one of all possibilities constrained by available data in optimal way.

  5. GRACE, time-varying gravity, Earth system dynamics and climate change

    International Nuclear Information System (INIS)

    Wouters, B; Bonin, J A; Chambers, D P; Riva, R E M; Sasgen, I; Wahr, J

    2014-01-01

    Continuous observations of temporal variations in the Earth's gravity field have recently become available at an unprecedented resolution of a few hundreds of kilometers. The gravity field is a product of the Earth's mass distribution, and these data—provided by the satellites of the Gravity Recovery And Climate Experiment (GRACE)—can be used to study the exchange of mass both within the Earth and at its surface. Since the launch of the mission in 2002, GRACE data has evolved from being an experimental measurement needing validation from ground truth, to a respected tool for Earth scientists representing a fixed bound on the total change and is now an important tool to help unravel the complex dynamics of the Earth system and climate change. In this review, we present the mission concept and its theoretical background, discuss the data and give an overview of the major advances GRACE has provided in Earth science, with a focus on hydrology, solid Earth sciences, glaciology and oceanography. (review article)

  6. User Guide and Documentation for Five MODFLOW Ground-Water Modeling Utility Programs

    Science.gov (United States)

    Banta, Edward R.; Paschke, Suzanne S.; Litke, David W.

    2008-01-01

    This report documents five utility programs designed for use in conjunction with ground-water flow models developed with the U.S. Geological Survey's MODFLOW ground-water modeling program. One program extracts calculated flow values from one model for use as input to another model. The other four programs extract model input or output arrays from one model and make them available in a form that can be used to generate an ArcGIS raster data set. The resulting raster data sets may be useful for visual display of the data or for further geographic data processing. The utility program GRID2GRIDFLOW reads a MODFLOW binary output file of cell-by-cell flow terms for one (source) model grid and converts the flow values to input flow values for a different (target) model grid. The spatial and temporal discretization of the two models may differ. The four other utilities extract selected 2-dimensional data arrays in MODFLOW input and output files and write them to text files that can be imported into an ArcGIS geographic information system raster format. These four utilities require that the model cells be square and aligned with the projected coordinate system in which the model grid is defined. The four raster-conversion utilities are * CBC2RASTER, which extracts selected stress-package flow data from a MODFLOW binary output file of cell-by-cell flows; * DIS2RASTER, which extracts cell-elevation data from a MODFLOW Discretization file; * MFBIN2RASTER, which extracts array data from a MODFLOW binary output file of head or drawdown; and * MULT2RASTER, which extracts array data from a MODFLOW Multiplier file.

  7. Grace announces coal-to-methanol project

    Energy Technology Data Exchange (ETDEWEB)

    Myers, R

    1980-02-15

    WR Grace and Co. are planning a feasibility study for a plant to produce 5000 tons/day of methanol and 6000 tons/day of carbon dioxide from captive coal reserves in Colorado. The study will be performed by Energy Transition Co. (ETCo). The producers would be used for pipeline transmission of pulverised coal, probably to California. At the destination the coal would go to a power station, the methanol to a gas turbine and the carbon dioxide to an oil producer for tertiary recovery.

  8. The design, validation, and performance of Grace

    Directory of Open Access Journals (Sweden)

    Ru Zhu

    2016-05-01

    Full Text Available The design, validation and performance of Grace, a GPU-accelerated micromagnetic simulation software, are presented. The software adopts C+ + Accelerated Massive Parallelism (C+ + AMP so that it runs on GPUs from various hardware vendors including NVidia, AMD and Intel. At large simulation scales, up to two orders of magnitude of speedup factor is observed, compared to CPU-based micromagnetic simulation software OOMMF. The software can run on high-end professional GPUs as well as budget personal laptops, and is free to download.

  9. Along-track geopotential difference and deflection of the vertical from grace range rate : Use of GEOGRACE

    NARCIS (Netherlands)

    Tangdamrongsub, N.; Hwang, Cheinway

    2016-01-01

    We present a theory and numerical algorithm to directly determine the time-varying along-track geopotential difference and deflection of the vertical at the Gravity Recovery and Climate Experiment (GRACE) satellite altitude. The determination was implemented using the GEOGRACE computer program

  10. Isotope Brayton ground demonstration testing and flight qualification. Volume 1. Technical program

    Energy Technology Data Exchange (ETDEWEB)

    1974-12-09

    A program is proposed for the ground demonstration, development, and flight qualification of a radioisotope nuclear heated dynamic power system for use on space missions beginning in the 1980's. This type of electrical power system is based upon and combines two aerospace technologies currently under intense development; namely, the MHW isotope heat source and the closed Brayton cycle gas turbine. This power system represents the next generation of reliable, efficient economic electrical power equipment for space, and will be capable of providing 0.5 to 2.0 kW of electric power to a wide variety of spacecraft for earth orbital and interplanetary missions. The immediate design will be based upon the requirements for the Air Force SURVSATCOM mission. The proposal is presented in three volumes plus an Executive Summary. This volume describes the tasks in the technical program.

  11. Interim site characterization report and ground-water monitoring program for the Hanford site solid waste landfill

    International Nuclear Information System (INIS)

    Fruland, R.M.; Hagan, R.A.; Cline, C.S.; Bates, D.J.; Evans, J.C.; Aaberg, R.L.

    1989-07-01

    Federal and state regulations governing the operation of landfills require utilization of ground-water monitoring systems to determine whether or not landfill operations impact ground water at the point of compliance (ground water beneath the perimeter of the facility). A detection-level ground-water monitoring system was designed, installed, and initiated at the Hanford Site Solid Waste Landfill (SWL). Chlorinated hydrocarbons were detected at the beginning of the ground-water monitoring program and continue to be detected more than 1 year later. The most probable source of the chlorinated hydrocarbons is washwater discharged to the SWL between 1985 and 1987. This is an interim report and includes data from the characterization work that was performed during well installation in 1987, such as field observations, sediment studies, and geophysical logging results, and data from analyses of ground-water samples collected in 1987 and 1988, such as field parameter measurements and chemical analyses. 38 refs., 27 figs., 8 tabs

  12. Ground test program for a full-size solar dynamic heat receiver

    Science.gov (United States)

    Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, T. W.

    1991-01-01

    Test hardware, facilities, and procedures were developed to conduct ground testing of a full-size, solar dynamic heat receiver in a partially simulated, low earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment was designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed-Brayton cycle engine simulator to circulate and condition the helium-xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described.

  13. A comparison of the gravity field over Central Europe from superconducting gravimeters, GRACE and global hydrological models, using EOF analysis

    Science.gov (United States)

    Crossley, David; de Linage, Caroline; Hinderer, Jacques; Boy, Jean-Paul; Famiglietti, James

    2012-05-01

    We analyse data from seven superconducting gravimeter (SG) stations in Europe from 2002 to 2007 from the Global Geodynamics Project (GGP) and compare seasonal variations with data from GRACE and several global hydrological models - GLDAS, WGHM and ERA-Interim. Our technique is empirical orthogonal function (EOF) decomposition of the fields that allows for the inherent incompatibility of length scales between ground and satellite observations. GGP stations below the ground surface pose a problem because part of the attraction from soil moisture comes from above the gravimeter, and this gives rise to a complex (mixed) gravity response. The first principle component (PC) of the EOF decomposition is the main indicator for comparing the fields, although for some of the series it accounts for only about 50 per cent of the variance reduction. PCs for GRACE solutions RL04 from CSR and GFZ are filtered with a cosine taper (degrees 20-40) and a Gaussian window (350 km). Significant differences are evident between GRACE solutions from different groups and filters, though they all agree reasonably well with the global hydrological models for the predominantly seasonal signal. We estimate the first PC at 10-d sampling to be accurate to 1 μGal for GGP data, 1.5 μGal for GRACE data and 1 μGal between the three global hydrological models. Within these limits the CNES/GRGS solution and ground GGP data agree at the 79 per cent level, and better when the GGP solution is restricted to the three above-ground stations. The major limitation on the GGP side comes from the water mass distribution surrounding the underground instruments that leads to a complex gravity effect. To solve this we propose a method for correcting the SG residual gravity series for the effects of soil moisture above the station.

  14. Assessing groundwater depletion and dynamics using GRACE and InSAR: Potential and limitations

    Science.gov (United States)

    Castellazzi, Pascal; Martel, Richard; Galloway, Devin L.; Longuevergne, Laurent; Rivera, Alfonso

    2016-01-01

    In the last decade, remote sensing of the temporal variation of ground level and gravity has improved our understanding of groundwater dynamics and storage. Mass changes are measured by GRACE (Gravity Recovery and Climate Experiment) satellites, whereas ground deformation is measured by processing synthetic aperture radar satellites data using the InSAR (Interferometry of Synthetic Aperture Radar) techniques. Both methods are complementary and offer different sensitivities to aquifer system processes. GRACE is sensitive to mass changes over large spatial scales (more than 100,000 km2). As such, it fails in providing groundwater storage change estimates at local or regional scales relevant to most aquifer systems, and at which most groundwater management schemes are applied. However, InSAR measures ground displacement due to aquifer response to fluid-pressure changes. InSAR applications to groundwater depletion assessments are limited to aquifer systems susceptible to measurable deformation. Furthermore, the inversion of InSAR-derived displacement maps into volume of depleted groundwater storage (both reversible and largely irreversible) is confounded by vertical and horizontal variability of sediment compressibility. During the last decade, both techniques have shown increasing interest in the scientific community to complement available in situ observations where they are insufficient. In this review, we present the theoretical and conceptual bases of each method, and present idealized scenarios to highlight the potential benefits and challenges of combining these techniques to remotely assess groundwater storage changes and other aspects of the dynamics of aquifer systems.

  15. Correcting GRACE gravity fields for ocean tide effects

    DEFF Research Database (Denmark)

    Knudsen, Per; Andersen, Ole Baltazar

    2002-01-01

    [1] The GRACE mission will be launch in early 2002 and will map the Earth's gravity fields and its variations with unprecedented accuracy during its 5-year lifetime. Unless ocean tide signals and their load upon the solid earth are removed from the GRACE data, their long period aliases obscure more...... tide model if altimetry corrected for inverted barometer effects was used in its derivation. To study the temporal characteristics of the ocean tidal constituents when sampled by GRACE, approximate alias frequencies were derived assuming a sampling of half a sidereal day. Those results show...

  16. An overview of the joint FAA/NASA aircraft/ground runway friction program

    Science.gov (United States)

    Yager, Thomas J.

    1989-01-01

    There is a need for information on runways which may become slippery due to various forms and types of contaminants. Experience has shown that since the beginning of all weather aircraft operations, there have been landing and aborted takeoff incidents and/or accidents each year where aircraft have either run off the end or veered off the shoulder of low friction runways. NASA Langley's Landing and Impact Dynamics Branch is involved in several research programs directed towards obtaining a better understanding of how different tire properties interact with varying pavement surface characteristics to produce acceptable performance for aircraft ground handling requirements. One such effort, which was jointly supported by not only NASA and the FAA but by several aviation industry groups including the Flight Safety Foundation, is described.

  17. The ground support computer and in-orbit survey data analysis program for the SEEP experiment

    International Nuclear Information System (INIS)

    Voss, H.D.; Datlowe, D.W.; Mobilia, J.; Roselle, S.N.

    1985-01-01

    The ground support computer equipment (GSE) and production survey plot and analysis software are described for the Stimulated Emissions of Energetic Particles (SEEP) experiment on the S81-1 satellite. A general purpose satellite data acquisition circuit was developed based on a Z-80 portable microcomputer. By simply changing instrument control software and electrical connectors, automatic testing and control of the various SEEP instruments was accomplished. A new feature incorporated into the SEEP data analysis phase was the development of a correlative data base for all of the SEEP instruments. A CPU efficient survey plot program (with ephemeris) was developed to display the approximate 3100 hours of data, with a time resolution of 0.5 sec, from the ten instrument sensors. The details of the general purpose multigraph algorithms and plot formats are presented. For the first time new associations are being investigated of simultaneous particle, X-ray, optical and plasma density satellite measurements

  18. A Test Run of the EGSIEM Near Real-Time Service Based on GRACE Mission Data

    Science.gov (United States)

    Kvas, A.; Gruber, C.; Gouweleeuw, B.; Guntner, A.; Mayer-Gürr, T.; Flechtner, F. M.

    2017-12-01

    To enable the use of GRACE and GRACE-FO data for rapid monitoring applications, the EGSIEM (European Gravity Service for Improved Emergency Management) project, funded by the Horizon 2020 Framework Program for Research and Innovation of the European Union, has implemented a demonstrator for a near real-time (NRT) gravity field service. The goal of this service is to provide daily gravity field solutions with a maximum latency of five days. For this purpose, two independent approaches were developed at the German Research Centre for Geosciences (GFZ) and Graz University of Technology (TUG). Based on these daily gravity field solutions, statistical flood and drought indicators are derived by the EGSIEM Hydrological Service, developed at GFZ. The NRT products are subsequently provided to the Center for Satellite based Crisis Information (ZKI) at the German Aerospace Center as well as the Global Flood Awareness System (GloFAS) at the Joint Research Center of the European Commission. In the first part of this contribution, the performance of the service based on a statistical analysis of historical flood events during the GRACE period is evaluated. Then, results from the six month long operational test run of the service which started on April 1st 2017 are presented and a comparison between historical and operational gravity products and flood indicators is made.

  19. Estimation of regional mass anomalies from Gravity Recovery and Climate Experiment (GRACE) over Himalayan region

    Science.gov (United States)

    Agrawal, R.; Singh, S. K.; Rajawat, A. S.; Ajai

    2014-11-01

    Time-variable gravity changes are caused by a combination of postglacial rebound, redistribution of water and snow/ice on land and as well as in the ocean. The Gravity Recovery and Climate Experiment (GRACE) satellite mission, launched in 2002, provides monthly average of the spherical harmonic co-efficient. These spherical harmonic co-efficient describe earth's gravity field with a resolution of few hundred kilometers. Time-variability of gravity field represents the change in mass over regional level with accuracies in cm in terms of Water Equivalent Height (WEH). The WEH reflects the changes in the integrated vertically store water including snow cover, surface water, ground water and soil moisture at regional scale. GRACE data are also sensitive towards interior strain variation, surface uplift and surface subsidence cover over a large area. GRACE data was extracted over the three major Indian River basins, Indus, Ganga and Brahmaputra, in the Himalayas which are perennial source of fresh water throughout the year in Northern Indian Plain. Time series analysis of the GRACE data was carried out from 2003-2012 over the study area. Trends and amplitudes of the regional mass anomalies in the region were estimated using level 3 GRACE data product with a spatial resolution at 10 by 10 grid provided by Center for Space Research (CSR), University of Texas at Austin. Indus basin has shown a subtle decreasing trend from 2003-2012 however it was observed to be statistically insignificant at 95 % confidence level. Ganga and Brahmaputra basins have shown a clear decreasing trend in WEH which was also observed to be statistically significant. The trend analysis over Ganga and Brahamputra basins have shown an average annual change of -1.28 cm and -1.06 cm in terms of WEH whereas Indus basin has shown a slight annual change of -0.07 cm. This analysis will be helpful to understand the loss of mass in terms of WEH over Indian Himalayas and will be crucial for hydrological and

  20. Seasonal changes in the European gravity field from GRACE: A comparison with superconducting gravimeters and hydrology model predictions

    Science.gov (United States)

    Hinderer, Jacques; Andersen, Ole; Lemoine, Frank; Crossley, David; Boy, Jean-Paul

    2006-01-01

    This paper is devoted to the investigation of seasonal changes of the Earth's gravity field from GRACE satellites and the comparison with surface gravity measurements in Europe from the Global Geodynamics Project (GGP) sub-network, as well as with recent hydrology models for continental soil moisture and snow. We used gravity maps in Europe retrieved from the initial GRACE monthly solutions spanning a 21-month duration from April 2002 to December 2003 for various truncation levels of the initial spherical harmonic decomposition of the field. The transfer function between satellite-derived and ground gravity changes due to continental hydrology is studied and we also compute the theoretical ratio of gravity versus radial displacement (in μGal/mm) involved in the hydrological loading process. The 'mean' value (averaged in time and in space over Europe) from hydrologic forward modeling is found to be close to -1.0 μGal/mm and we show that this value can be explained by a strong low degree ( n = 5-6) peak in the hydrology amplitude spectrum. The dominant time-variable signal from GRACE is found to be annual with an amplitude and a phase both of which are in fair agreement with predictions in Europe from recent hydrology models. Initial results suggest that all three data sets (GRACE, hydrology and GGP) respond to annual changes in near-surface water in Europe of a few μGal (at length scales of ˜1000 km) that show a high value in winter and a summer minimum. Despite the limited time span of our analysis and the uncertainties in separating purely local effects from regional ones in superconducting gravimeter data, the calibration and validation aspects of the GRACE data processing based on the annual hydrology cycle in Europe are in progress.

  1. The GRACE system for the minimal supersymmetric standard model

    International Nuclear Information System (INIS)

    Tanaka, H.; Kaneko, T.; Jimbo, M.; Kon, T.

    1997-01-01

    The algorithm of constructing the Feynman amplitudes for the GRACE system is extended to processes involving supersymmetric particles. New vertex amplitude subroutines needed to compute these processes are now part of the CHANEL library. (orig.)

  2. REVIEW A SPACE FOR GRACE: TOWARDS AN AESTHETICS OF ...

    African Journals Online (AJOL)

    REVIEW. A SPACE FOR. GRACE: TOWARDS. AN AESTHETICS OF. PREACHING ... Cilliers' views of space and time are clearly post-Einstein and post-. Hawking. .... in the step-by-step, week-in-week-out process of sermon preparation. The.

  3. A Feynman graph selection tool in GRACE system

    International Nuclear Information System (INIS)

    Yuasa, Fukuko; Ishikawa, Tadashi; Kaneko, Toshiaki

    2001-01-01

    We present a Feynman graph selection tool grcsel, which is an interpreter written in C language. In the framework of GRACE, it enables us to get a subset of Feynman graphs according to given conditions

  4. Grace Omollo Misere and Anne Akoth Misere | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Combinatorics has led Grace to work on a conjecture proposed by John Conway, ... and governments in Kenya and the region improve their performance through the ... African women mathematical scientists working on climate change issues.

  5. Comparison of GRACE with in situ hydrological measurement data ...

    African Journals Online (AJOL)

    Comparison of GRACE with in situ hydrological measurement data shows storage depletion in Hai River basin, Northern China. ... of the world, their application in conjunction with hydrological models could improve hydrological studies.

  6. Benefits and Pitfalls of GRACE Terrestrial Water Storage Data Assimilation

    Science.gov (United States)

    Girotto, Manuela

    2018-01-01

    Satellite observations of terrestrial water storage (TWS) from the Gravity Recovery and Climate Experiment (GRACE) mission have a coarse resolution in time (monthly) and space (roughly 150,000 sq km at midlatitudes) and vertically integrate all water storage components over land, including soil moisture and groundwater. Nonetheless, data assimilation can be used to horizontally downscale and vertically partition GRACE-TWS observations. This presentation illustrates some of the benefits and drawbacks of assimilating TWS observations from GRACE into a land surface model over the continental United States and India. The assimilation scheme yields improved skill metrics for groundwater compared to the no-assimilation simulations. A smaller impact is seen for surface and root-zone soil moisture. Further, GRACE observes TWS depletion associated with anthropogenic groundwater extraction. Results from the assimilation emphasize the importance of representing anthropogenic processes in land surface modeling and data assimilation systems.

  7. PHAST--a program for simulating ground-water flow, solute transport, and multicomponent geochemical reactions

    Science.gov (United States)

    Parkhurst, David L.; Kipp, Kenneth L.; Engesgaard, Peter; Charlton, Scott R.

    2004-01-01

    The computer program PHAST simulates multi-component, reactive solute transport in three-dimensional saturated ground-water flow systems. PHAST is a versatile ground-water flow and solute-transport simulator with capabilities to model a wide range of equilibrium and kinetic geochemical reactions. The flow and transport calculations are based on a modified version of HST3D that is restricted to constant fluid density and constant temperature. The geochemical reactions are simulated with the geochemical model PHREEQC, which is embedded in PHAST. PHAST is applicable to the study of natural and contaminated ground-water systems at a variety of scales ranging from laboratory experiments to local and regional field scales. PHAST can be used in studies of migration of nutrients, inorganic and organic contaminants, and radionuclides; in projects such as aquifer storage and recovery or engineered remediation; and in investigations of the natural rock-water interactions in aquifers. PHAST is not appropriate for unsaturated-zone flow, multiphase flow, density-dependent flow, or waters with high ionic strengths. A variety of boundary conditions are available in PHAST to simulate flow and transport, including specified-head, flux, and leaky conditions, as well as the special cases of rivers and wells. Chemical reactions in PHAST include (1) homogeneous equilibria using an ion-association thermodynamic model; (2) heterogeneous equilibria between the aqueous solution and minerals, gases, surface complexation sites, ion exchange sites, and solid solutions; and (3) kinetic reactions with rates that are a function of solution composition. The aqueous model (elements, chemical reactions, and equilibrium constants), minerals, gases, exchangers, surfaces, and rate expressions may be defined or modified by the user. A number of options are available to save results of simulations to output files. The data may be saved in three formats: a format suitable for viewing with a text editor; a

  8. Improving groundwater storage and soil moisture estimates by assimilating GRACE, SMOS, and SMAP data into CABLE using ensemble Kalman batch smoother and particle batch smoother frameworks

    Science.gov (United States)

    Han, S. C.; Tangdamrongsub, N.; Yeo, I. Y.; Dong, J.

    2017-12-01

    Soil moisture and groundwater storage are important information for comprehensive understanding of the climate system and accurate assessment of the regional/global water resources. It is possible to derive the water storage from land surface models but the outputs are commonly biased by inaccurate forcing data, inefficacious model physics, and improper model parameter calibration. To mitigate the model uncertainty, the observation (e.g., from remote sensing as well as ground in-situ data) are often integrated into the models via data assimilation (DA). This study aims to improve the estimation of soil moisture and groundwater storage by simultaneously assimilating satellite observations from the Gravity Recovery And Climate Experiment (GRACE), the Soil Moisture Ocean Salinity (SMOS), and the Soil Moisture Active Passive (SMAP) into the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model using the ensemble Kalman batch smoother (EnBS) and particle batch smoother (PBS) frameworks. The uncertainty of GRACE observation is obtained rigorously from the full error variance-covariance matrix of the GRACE data product. This method demonstrates the use of a realistic representative of GRACE uncertainty, which is spatially correlated in nature, leads to a higher accuracy of water storage computation. Additionally, the comparison between EnBS and PBS results is discussed to understand the filter's performance, limitation, and suitability. The joint DA is demonstrated in the Goulburn catchment, South-East Australia, where diverse ground observations (surface soil moisture, root-zone soil moisture, and groundwater level) are available for evaluation of our DA results. Preliminary results show that both smoothers provide significant improvement of surface soil moisture and groundwater storage estimates. Importantly, our developed DA scheme disaggregates the catchment-scale GRACE information into finer vertical and spatial scales ( 25 km). We present an

  9. Results from GRACE/SUSY at one-loop

    International Nuclear Information System (INIS)

    Fujimoto, J.; Ishikawa, T.; Kurihara, Y.; Jimbo, M.; Yasui, Y.; Kaneko, T.; Kon, T.; Kuroda, M.; Shimizu, Y.

    2007-01-01

    We report the recent development on the SUSY calculations with the help of GRACE system. GRACE/SUSY/1LOOP is the computer code which can generate Feynman diagrams in the MSSM automatically and compute one-loop amplitudes in the numerical way. We present new results of various two-body widths and chargino pair production at ILC (international linear collider) at one-loop level. (author)

  10. Greenland ice mass balance from GPS, GRACE and ICESat

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

    Greenland, using stereoscopic coverage by aerial photographs recorded in 1985, and subsequent comparative surface elevation data from ICESat (Ice, Cloud and land Elevation Satellite) and ATM (Airborne Topographic Mapper) supplemented with measurements from GPS and the Gravity Recovery and Climate Experiment...... (GRACE) satellite gravity mission, launched in March, 2002. The GRACE results provide a direct measure of mass loss, while the GPS data are used to monitor crustal uplift caused by ice mass loss close to the GPS sites....

  11. Constraining precipitation amount and distribution over cold regions using GRACE

    Science.gov (United States)

    Behrangi, A.; Reager, J. T., II; Gardner, A. S.; Fisher, J.

    2017-12-01

    Current quantitative knowledge on the amount and distribution of precipitation in high-elevation and high latitude regions is limited due to instrumental and retrieval shortcomings. Here we demonstrate how that satellite gravimetry (Gravity Recovery and Climate Experiment, GRACE) can be used to provide an independent estimate of monthly accumulated precipitation using mass balance. Results showed that the GRACE-based precipitation estimate has the highest agreement with most of the commonly used precipitation products in summer, but it deviates from them in cold months, when the other products are expected to have larger error. We also observed that as near surface temperature decreases products tend to underestimate accumulated precipitation retrieved from GRACE. The analysis performed using various products such as GPCP, GPCC, TRMM, and gridded station data over vast regions in high latitudes and two large endorheic basins in High Mountain Asia. Based on the analysis over High Mountain Asia it was found that most of the products capture about or less than 50% of the total precipitation estimated using GRACE in winter. Overall, GPCP showed better agreement with GRACE estimate than other products. Yet on average GRACE showed 30% more annual precipitation than GPCP in the study basin.

  12. Predictive power of the grace score in population with diabetes.

    Science.gov (United States)

    Baeza-Román, Anna; de Miguel-Balsa, Eva; Latour-Pérez, Jaime; Carrillo-López, Andrés

    2017-12-01

    Current clinical practice guidelines recommend risk stratification in patients with acute coronary syndrome (ACS) upon admission to hospital. Diabetes mellitus (DM) is widely recognized as an independent predictor of mortality in these patients, although it is not included in the GRACE risk score. The objective of this study is to validate the GRACE risk score in a contemporary population and particularly in the subgroup of patients with diabetes, and to test the effects of including the DM variable in the model. Retrospective cohort study in patients included in the ARIAM-SEMICYUC registry, with a diagnosis of ACS and with available in-hospital mortality data. We tested the predictive power of the GRACE score, calculating the area under the ROC curve. We assessed the calibration of the score and the predictive ability based on type of ACS and the presence of DM. Finally, we evaluated the effect of including the DM variable in the model by calculating the net reclassification improvement. The GRACE score shows good predictive power for hospital mortality in the study population, with a moderate degree of calibration and no significant differences based on ACS type or the presence of DM. Including DM as a variable did not add any predictive value to the GRACE model. The GRACE score has an appropriate predictive power, with good calibration and clinical applicability in the subgroup of diabetic patients. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  13. Grace buys aquatic quimica to boost water treatment stake

    International Nuclear Information System (INIS)

    Hunter, D.

    1993-01-01

    How W.R. Grace (Boca Raton, FL) president and newly appointed CEO J.P. Bolduc plans to expand Grace's core businesses following his drastic portfolio pruning during the past 18 months is a key question for Grace watchers. Grace's acquisition of $70-million/year water treatment firm Aquatec Quimica (Sao Paulo) is one indicator. Grace's $300-million/year Dearborn water treatment business is currently a weak number three [in the world market], and we want to be number one or number two, nothing less, Bolduc insists. The Aquatc buy meets his criterion of a synergistic and strategic acquisition with which he plans to expand the business, backed by more focused R ampersand D. Disposal last month of Homco oil field services operation, for $98.5 million, takes Bolduc toward his $500-million target for the year for asset sales. These totaled $1.1 billion at the end of 1992. The final tally will be more than the $1.5-billion target previously stated, Bolduc says, due to higher realizations on certain sales and additions to the list, including Grace Culinary and Colowyo Coal

  14. Seasonal changes in the European gravity field from GRACE: A comparison with superconducting gravimeters and hydrology model predictions

    DEFF Research Database (Denmark)

    Hinderer, J.; Andersen, Ole Baltazar; Lemoine, F.

    2006-01-01

    This paper is devoted to the investigation of seasonal changes of the Earth's gravity field from GRACE satellites and the comparison with surface gravity measurements in Europe from the Global Geodynamics Project (GGP) sub-network, as well as with recent hydrology models for continental soil...... moisture and snow. We used gravity maps in Europe retrieved from the initial GRACE monthly solutions spanning a 21 -month duration from April 2002 to December 2003 for various truncation levels of the initial spherical harmonic decomposition of the field. The transfer function between satellite......-derived and ground gravity changes due to continental hydrology is studied and we also compute the theoretical ratio of gravity versus radial displacement (in mu Gal/mm) involved in the hydrological loading process. The 'mean' value (averaged in time and in space over Europe) from hydrologic forward modeling...

  15. Detecting seasonal and long-term vertical displacement in the North China Plain using GRACE and GPS

    Directory of Open Access Journals (Sweden)

    L. Wang

    2017-06-01

    Full Text Available In total, 29 continuous Global Positioning System (GPS time series data together with data from Gravity Recovery and Climate Experiment (GRACE are analysed to determine the seasonal displacements of surface loadings in the North China Plain (NCP. Results show significant seasonal variations and a strong correlation between GPS and GRACE results in the vertical displacement component; the average correlation and weighted root-mean-squares (WRMS reduction between GPS and GRACE are 75.6 and 28.9 % respectively, when atmospheric and non-tidal ocean effects were removed, but the annual peak-to-peak amplitude of GPS (1.2–6.3 mm is greater than the data (1.0–2.2 mm derived from GRACE. We also calculate the trend rate as well as the seasonal signal caused by the mass load change from GRACE data; the rate of GRACE-derived terrestrial water storage (TWS loss (after multiplying by the scaling factor in the NCP was 3.39 cm yr−1 (equivalent to 12.42 km3 yr−1 from 2003 to 2009. For a 10-year time span (2003 to 2012, the rate loss of TWS was 2.57 cm yr−1 (equivalent to 9.41 km3 yr−1, which is consistent with the groundwater storage (GWS depletion rate (the rate losses of GWS were 2.49 and 2.72 cm yr−1 during 2003–2009 and 2003–2012 respectively estimated from GRACE-derived results after removing simulated soil moisture (SM data from the Global Land Data Assimilation System (GLDAS/Noah model. We also found that GRACE-derived GWS changes are in disagreement with the groundwater level changes from observations of shallow aquifers from 2003 to 2009, especially between 2010 and 2013. Although the shallow groundwater can be recharged from the annual climate-driven rainfall, the important facts indicate that GWS depletion is more serious in deep aquifers. The GRACE-derived result shows an overall uplift in the whole region at the 0.37–0.95 mm yr−1 level from 2004 to 2009, but the rate of change direction is

  16. 13 CFR 120.1425 - Grounds for enforcement actions-Intermediaries participating in the Microloan Program and NTAPs.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Grounds for enforcement actions-Intermediaries participating in the Microloan Program and NTAPs. 120.1425 Section 120.1425 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Risk-Based Lender Oversight Enforcement Actions § 120...

  17. Global Assessment of New GRACE Mascons Solutions for Hydrologic Applications

    Science.gov (United States)

    Save, H.; Zhang, Z.; Scanlon, B. R.; Wiese, D. N.; Landerer, F. W.; Long, D.; Longuevergne, L.; Chen, J.

    2016-12-01

    Advances in GRACE (Gravity Recovery and Climate Experiment) satellite data processing using new mass concentration (mascon) solutions have greatly increased the spatial localization and amplitude of recovered total Terrestrial Water Storage (TWS) signals; however, limited testing has been conduct on land hydrologic applications. In this study we compared TWS anomalies from (1) Center for Space Research mascons (CSR-M) solution with (2) NASA JPL mascon (JPL-M) solution, and with (3) a CSR gridded spherical harmonic rescaled (sf) solution from Tellus (CSRT-GSH.sf) in 176 river basins covering 80% of the global land area. There is good correspondence in TWS anomalies from mascons (CSR-M and JPL-M) and SH solutions based on high correlations between time series (rank correlation coefficients mostly >0.9). The long-term trends in basin TWS anomalies represent a relatively small signal (up to ±20 mm/yr) with differences among GRACE solutions and inter-basin variability increasing with decreasing basin size. Long-term TWS declines are greatest in (semi)arid and irrigated basins. Annual and semiannual signals have much larger amplitudes (up to ±250 mm). There is generally good agreement among GRACE solutions, increasing confidence in seasonal fluctuations from GRACE data. Rescaling spherical harmonics to restore lost signal increases agreement with mascons solutions for long-term trends and seasonal fluctuations. There are many advantages to using GRACE mascons solutions relative to SH solutions, such as reduced leakage from land to ocean increasing signal amplitude, and constraining results by applying geophysical data during processing with little or no post-processing requirements, making mascons more user friendly for non-geodetic users. This inter-comparison of various GRACE solutions should allow hydrologists to better select suitable GRACE products for hydrologic applications.

  18. GRACE storage-runoff hystereses reveal the dynamics of ...

    Science.gov (United States)

    Watersheds function as integrated systems where climate and geology govern the movement of water. In situ instrumentation can provide local-scale insights into the non-linear relationship between streamflow and water stored in a watershed as snow, soil moisture, and groundwater. However, there is a poor understanding of these processes at the regional scale—primarily because of our inability to measure water stores and fluxes in the subsurface. Now NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites quantify changes in the amount of water stored across and through the Earth, providing measurements of regional hydrologic behavior. Here we apply GRACE data to characterize for the first time how regional watersheds function as simple, dynamic systems through a series of hysteresis loops. While the physical processes underlying the loops are inherently complex, the vertical integration of terrestrial water in the GRACE signal provides process-based insights into the dynamic and non-linear function of regional-scale watersheds. We use this process-based understanding with GRACE data to effectively forecast seasonal runoff (mean R2 of 0.91) and monthly runoff (mean R2 of 0.77) in three regional-scale watersheds (>150,000 km2) of the Columbia River Basin, USA. Data from the Gravity Recovery and Climate Experiment (GRACE) satellites provide a novel dataset for understanding changes in the amount of water stored across and through the surface of the Ear

  19. The unrealised ethical potential of the Methodist theology of prevenient grace

    Directory of Open Access Journals (Sweden)

    David N. Field

    2015-10-01

    Full Text Available This article examines the unrealised ethical potential of the theology of prevenient grace. It begins with a brief analysis of John Wesley’s rejection of slavery as rooted in his theology of prevenient grace. This is demonstrated in the next section which analyses Wesley’s notion of prevenient grace. This is followed by a constructive proposal for a contemporary theology of prevenient grace and some ethical implications of this theology, for contemporary social and political ethics, are developed.

  20. Application of GRACE to the Evaluation of an Ice Flow Model of the Greenland Ice Sheet

    Science.gov (United States)

    Schlegel, N.; Wiese, D. N.; Watkins, M. M.; Larour, E. Y.; Box, J. E.; Fettweis, X.; van den Broeke, M. R.; Morlighem, M.; Boening, C.; Seroussi, H. L.

    2014-12-01

    Quantifying Greenland's future contribution to sea level rise is a challenging task and requires accurate estimates of ice flow sensitivity to climate change. Transient ice flow models are promising tools for estimating future ice sheet behavior. However, confidence in these types of future projections is low, especially because evaluation of model historical runs is so challenging due to the scarcity of continental-wide data for validation. For more than a decade, NASA's GRACE has continuously acquired time-variable measurements of the Earth's gravity field and has provided unprecedented surveillance of mass balance of the ice sheets, offering an opportunity for ice sheet model evaluation. Here, we take advantage of a new high-resolution (~300 km) monthly mascon solution for the purpose of mass balance comparison with an independent, historical ice flow model simulation using the Ice Sheet System Model (ISSM). The comparison highlights which regions of the ice sheet differ most from GRACE. Investigation of regional differences in trends and seasonal amplitudes between simulations forced with three different Regional Climate Model (RCM)-based estimates of surface mass balance (SMB) allows us to make conclusions about the relative contributions of various error sources in the model hindcast. This study constitutes the first regional comparison of GRACE data and an ice sheet model. Conclusions will aid in the improvement of RCM SMB estimates as well as ice sheet simulation estimates of present and future rates of sea level rise. This work was performed at the California Institute of Technology's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration's Cryosphere Program and President's and Director's Fund Program.

  1. Synergies Between Grace and Regional Atmospheric Modeling Efforts

    Science.gov (United States)

    Kusche, J.; Springer, A.; Ohlwein, C.; Hartung, K.; Longuevergne, L.; Kollet, S. J.; Keune, J.; Dobslaw, H.; Forootan, E.; Eicker, A.

    2014-12-01

    In the meteorological community, efforts converge towards implementation of high-resolution (precipitation, evapotranspiration and runoff data; confirming that the model does favorably at representing observations. We show that after GRACE-derived bias correction, basin-average hydrological conditions prior to 2002 can be reconstructed better than before. Next, comparing GRACE with CLM forced by EURO-CORDEX simulations allows identifying processes needing improvement in the model. Finally, we compare COSMO-EU atmospheric pressure, a proxy for mass corrections in satellite gravimetry, with ERA-Interim over Europe at timescales shorter/longer than 1 month, and spatial scales below/above ERA resolution. We find differences between regional and global model more pronounced at high frequencies, with magnitude at sub-grid scale and larger scale corresponding to 1-3 hPa (1-3 cm EWH); relevant for the assessment of post-GRACE concepts.

  2. Land Water Storage within the Congo Basin Inferred from GRACE Satellite Gravity Data

    Science.gov (United States)

    Crowley, John W.; Mitrovica, Jerry X.; Bailey, Richard C.; Tamisiea, Mark E.; Davis, James L.

    2006-01-01

    GRACE satellite gravity data is used to estimate terrestrial (surface plus ground) water storage within the Congo Basin in Africa for the period of April, 2002 - May, 2006. These estimates exhibit significant seasonal (30 +/- 6 mm of equivalent water thickness) and long-term trends, the latter yielding a total loss of approximately 280 km(exp 3) of water over the 50-month span of data. We also combine GRACE and precipitation data set (CMAP, TRMM) to explore the relative contributions of the source term to the seasonal hydrological balance within the Congo Basin. We find that the seasonal water storage tends to saturate for anomalies greater than 30-44 mm of equivalent water thickness. Furthermore, precipitation contributed roughly three times the peak water storage after anomalously rainy seasons, in early 2003 and 2005, implying an approximately 60-70% loss from runoff and evapotranspiration. Finally, a comparison of residual land water storage (monthly estimates minus best-fitting trends) in the Congo and Amazon Basins shows an anticorrelation, in agreement with the 'see-saw' variability inferred by others from runoff data.

  3. Drought Analysis of the Haihe River Basin Based on GRACE Terrestrial Water Storage

    Directory of Open Access Journals (Sweden)

    Jianhua Wang

    2014-01-01

    Full Text Available The Haihe river basin (HRB in the North China has been experiencing prolonged, severe droughts in recent years that are accompanied by precipitation deficits and vegetation wilting. This paper analyzed the water deficits related to spatiotemporal variability of three variables of the gravity recovery and climate experiment (GRACE derived terrestrial water storage (TWS data, precipitation, and EVI in the HRB from January 2003 to January 2013. The corresponding drought indices of TWS anomaly index (TWSI, precipitation anomaly index (PAI, and vegetation anomaly index (AVI were also compared for drought analysis. Our observations showed that the GRACE-TWS was more suitable for detecting prolonged and severe droughts in the HRB because it can represent loss of deep soil water and ground water. The multiyear droughts, of which the HRB has sustained for more than 5 years, began in mid-2007. Extreme drought events were detected in four periods at the end of 2007, the end of 2009, the end of 2010, and in the middle of 2012. Spatial analysis of drought risk from the end of 2011 to the beginning of 2012 showed that human activities played an important role in the extent of drought hazards in the HRB.

  4. Monitoring groundwater storage changes in the highly seasonal humid tropics: Validation of GRACE measurements in the Bengal Basin

    Science.gov (United States)

    Shamsudduha, M.; Taylor, R. G.; Longuevergne, L.

    2012-02-01

    Satellite monitoring of changes in terrestrial water storage provides invaluable information regarding the basin-scale dynamics of hydrological systems where ground-based records are limited. In the Bengal Basin of Bangladesh, we test the ability of satellite measurements under the Gravity Recovery and Climate Experiment (GRACE) to trace both the seasonality and trend in groundwater storage associated with intensive groundwater abstraction for dry-season irrigation and wet-season (monsoonal) recharge. We show that GRACE (CSR, GRGS) datasets of recent (2003 to 2007) groundwater storage changes (ΔGWS) correlate well (r = 0.77 to 0.93, p value CSR. Changes in surface water storage estimated from a network of 298 river gauging stations and soil-moisture derived from Land Surface Models explain 22% and 33% of ΔTWS, respectively. Groundwater depletion estimated from borehole hydrographs (-0.52 ± 0.30 km3 yr-1) is within the range of satellite-derived estimates (-0.44 to -2.04 km3 yr-1) that result from uncertainty associated with the simulation of soil moisture (CLM, NOAH, VIC) and GRACE signal-processing techniques. Recent (2003 to 2007) estimates of groundwater depletion are substantially greater than long-term (1985 to 2007) mean (-0.21 ± 0.03 km3 yr-1) and are explained primarily by substantial increases in groundwater abstraction for the dry-season irrigation and public water supplies over the last two decades.

  5. GRACE score predicts heart failure admission following acute coronary syndrome.

    Science.gov (United States)

    McAllister, David A; Halbesma, Nynke; Carruthers, Kathryn; Denvir, Martin; Fox, Keith A

    2015-04-01

    Congestive heart failure (CHF) is a common and preventable complication of acute coronary syndrome (ACS). Nevertheless, ACS risk scores have not been shown to predict CHF risk. We investigated whether the at-discharge Global Registry of Acute Coronary Events (GRACE) score predicts heart failure admission following ACS. Five-year mortality and hospitalization data were obtained for patients admitted with ACS from June 1999 to September 2009 to a single centre of the GRACE registry. CHF was defined as any admission assigned WHO International Classification of Diseases 10 diagnostic code I50. The hazard ratio (HR) for CHF according to GRACE score was estimated in Cox models adjusting for age, gender and the presence of CHF on index admission. Among 1,956 patients, CHF was recorded on index admission in 141 patients (7%), and 243 (12%) were admitted with CHF over 3.8 median years of follow-up. Compared to the lowest quintile, patients in the highest GRACE score quintile had more CHF admissions (116 vs 17) and a shorter time to first admission (1.2 vs 2.0 years, HR 9.87, 95% CI 5.93-16.43). Per standard deviation increment in GRACE score, the instantaneous risk was more than two-fold higher (HR 2.28; 95% CI 2.02-2.57), including after adjustment for CHF on index admission, age and gender (HR 2.49; 95% CI 2.06-3.02). The C-statistic for CHF admission at 1-year was 0.74 (95% CI 0.70-0.79). The GRACE score predicts CHF admission, and may therefore be used to target ACS patients at high risk of CHF with clinical monitoring and therapies. © The European Society of Cardiology 2014.

  6. Density and fledging success of ground-nesting passerines in Conservation Reserve Program fields in the northeastern Great Plains

    Science.gov (United States)

    Koford, Rolf R.

    1999-01-01

    The Conservation Reserve Program, initiated in 1985, was designed primarily to reduce soil erosion and crop surpluses. A secondary benefit was the provision of habitat for wildlife. Grassland bird populations, many of which declined in the decades prior to the Conservation Reserve Program, may have benefited from the Conservation Reserve Program if reproduction in this newly available habitat has been at least as high as it would have been in the absence of the Conservation Reserve Program. On study areas in North Dakota and Minnesota, I examined breeding densities and fledging success of grassland birds in Conservation Reserve Program fields and in an alternative habitat of similar structure, idle grassland fields on federal Waterfowl Production Areas. Fields were 10 to 25 hectares in size. The avifaunas of these two habitats were similar, although brush-dependent species were more abundant on Waterfowl Protection Areas. The common species in these habitats included ones whose continental populations have declined, such as Grasshopper Sparrow (Ammodramus savannarum), Savannah Sparrow (Passerculus sandwichensis), and Bobolink (Dolichonyx oryzivorus). These ground-nesting species were pooled with other ground nesters in an analysis of fledging success, which revealed no significant differences between habitats, between states, or among years (1991-1993). Predation was the primary cause of nest failure. I concluded that Conservation Reserve Program fields in this region were suitable breeding habitat for several species whose populations had declined prior to the Conservation Reserve Program era. This habitat appeared to be as secure for nests of ground-nesting birds as another suitable habitat in North Dakota and Minnesota.

  7. Global analysis of approaches for deriving total water storage changes from GRACE satellites and implications for groundwater storage change estimation

    Science.gov (United States)

    Long, D.; Scanlon, B. R.; Longuevergne, L.; Chen, X.

    2015-12-01

    Increasing interest in use of GRACE satellites and a variety of new products to monitor changes in total water storage (TWS) underscores the need to assess the reliability of output from different products. The objective of this study was to assess skills and uncertainties of different approaches for processing GRACE data to restore signal losses caused by spatial filtering based on analysis of 1°×1° grid scale data and basin scale data in 60 river basins globally. Results indicate that scaling factors from six land surface models (LSMs), including four models from GLDAS-1 (Noah 2.7, Mosaic, VIC, and CLM 2.0), CLM 4.0, and WGHM, are similar over most humid, sub-humid, and high-latitude regions but can differ by up to 100% over arid and semi-arid basins and areas with intensive irrigation. Large differences in TWS anomalies from three processing approaches (scaling factor, additive, and multiplicative corrections) were found in arid and semi-arid regions, areas with intensive irrigation, and relatively small basins (e.g., ≤ 200,000 km2). Furthermore, TWS anomaly products from gridded data with CLM4.0 scaling factors and the additive correction approach more closely agree with WGHM output than the multiplicative correction approach. Estimation of groundwater storage changes using GRACE satellites requires caution in selecting an appropriate approach for restoring TWS changes. A priori ground-based data used in forward modeling can provide a powerful tool for explaining the distribution of signal gains or losses caused by low-pass filtering in specific regions of interest and should be very useful for more reliable estimation of groundwater storage changes using GRACE satellites.

  8. Applicability of a generic monitoring program for radioactive waste burial grounds at Oak Ridge National Laboratory and Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    1978-07-01

    Six burial grounds were evaluated at Oak Ridge to determine which would be most suitable for testing the generic monitoring approach, and two were selected. Burial Ground 4 was chosen because it is known to be leaking radioactivity and a monitoring program is desirable to determine the source, pattern and extent of the leakage. Burial Ground 6 was chosen because the most complete radiologic and geologic data is available and modern burial practices have been utilized at this site. At the Idaho National Engineering Laboratory (INEL) only one burial ground exists, the Radioactive Waste Management Complex (RWMC). The data available on the burial grounds are insufficient for an adequate understanding of radionuclide migration patterns and accordingly, inadequate for the design of reliable monitoring programs. It was decided, therefore, that preliminary monitoring programs should be designed in order to obtain additional data for a later implementation of reliable monitoring programs. The monitoring programs designed for ORNL consist primarily of the installation of surface water monitoring stations, the surveillance of trench sump wells, a test boring program to study subsurface geologic conditions, a ground water sampling program and the installation of instrumentation, specifically infiltrometers and evaporation pans, to develop data on site water balances. The program designed for the INEL burial ground includes installation of trench sumps, a ground water monitoring program, test borings to further define subsurface geohydrologic conditions and the installation of instrumentation to develop data on the site water balance. The estimated costs of implementing the recommended programs are about $420,820 for monitoring Burial Grounds 4 and 6 at Oak Ridge and $382,060 for monitoring the RWMC at INEL. 12 figures

  9. Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions

    International Nuclear Information System (INIS)

    1993-01-01

    This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake's ground motion is a function of the earthquake's magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. Therefore, empirically based approaches that are used for other regions, such as Western North America, are not appropriate for Eastern North America. Moreover, recent advances in science and technology have now made it possible to combine theoretical and empirical methods to develop new procedures and models for estimating ground motion. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. Specifically considered are magnitudes M from 5 to 8, distances from 0 to 500 km, and frequencies from 1 to 35 Hz. This document, Volume IV, provides Appendix 8.B, Laboratory Investigations of Dynamic Properties of Reference Sites

  10. Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions

    International Nuclear Information System (INIS)

    1993-01-01

    This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake's ground motion is a function of the earthquake's magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. Therefore, empirically based approaches that are used for other regions, such as Western North America, are not appropriate for Eastern North America. Moreover, recent advances in science and technology have now made it possible to combine theoretical and empirical methods to develop new procedures and models for estimating ground motion. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. Specifically considered are magnitudes M from 5 to 8, distances from 0 to 500 km, and frequencies from 1 to 35 Hz

  11. 3-D GRACE gravity model for the 2011 Japan earthquake

    Indian Academy of Sciences (India)

    Corresponding author. e-mail: rgss1fes@iitr.ac.in/rgssastry@gmail.com. The GRACE mission has contributed to the seismic characterization of major earthquakes in offshore ... −13μGal), fully accounting for co-seismic mass redistribution.

  12. In between St. Augustine and Luther: Grace and justification

    Directory of Open Access Journals (Sweden)

    Michael M. Ramos

    2014-12-01

    Full Text Available The view presented in this study emphasized grace as a cause of spiritual strength and justification of man. In understanding the deep meaning and nature of grace, this paper analyzes the formations given on the subject by two great minds, St. Augustine and Martin Luther. Because of the great influence of their work on the theology of grace and justification, this paper attempts to seek whether man’s understanding and belief of prudence would mean nothing at all, that any good that he will perform on his behalf would do nothing for his own justification. Thus it raises the question on the purpose of man’s freedom if his proprium is nothing and that divine prudence is the source of everything good. This led to the idea that grace is the primary energy source of man to make good, not by his own, but by divine prudence to obtain justification. Therefore, in this sense there is nothing good in man.

  13. Identifying water mass depletion in northern Iraq observed by GRACE

    NARCIS (Netherlands)

    Mulder, G.; Olsthoorn, T.N.; Al-manmi, D.A.M.A.; Schrama, E.J.O.; Smidt, E.H.

    2015-01-01

    Observations acquired by Gravity Recovery And Climate Experiment (GRACE) mission indicate a mass loss of 146 ± 6 mm equivalent water height (EWH) in northern Iraq between 2007 and 2009. These data are used as an independent validation of lake mass variations and a rainfall-runoff model, which is

  14. "Amazing Grace": Literature as a Window on Colonial Slavery.

    Science.gov (United States)

    Basker, James G.

    2003-01-01

    Describes the book, "Amazing Grace: An Anthology of Poems about Slavery 1660-1810." Presents poems, written by 250 writers, that focus on slavery during the 150 year period. Provides examples of materials included in this book and how it can enable students to increase their understanding of slavery. (CMK)

  15. Q&A: Grace Anne Koppel, Living Well with COPD

    Science.gov (United States)

    ... their own lives back is the most rewarding thing we have ever done. Read More "The Challenge of COPD" Articles Q&A: Grace Anne Koppel, Living Well with COPD / What is COPD? / What Causes COPD? / Getting Tested / Am I at Risk? / COPD Quiz Fall ...

  16. Attention, Asceticism, and Grace: Simone Weil and Higher Education

    Science.gov (United States)

    Roberts, Peter

    2011-01-01

    The work of the French thinker Simone Weil has exerted an important influence on scholars in a wide range of fields. To date, however, her writings have attracted comparatively little interest from educationists. This article discusses some of the key concepts in Weil's philosophy--gravity, grace, decreation, and attention--and assesses their…

  17. Terrestrial Water Storage from GRACE and Satellite Altimetry in the Okavango Delta (Botswana)

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Krogh, Pernille Engelbredt; Bauer-Gottwein, Peter

    2010-01-01

    New technology can for the first time enable the accurate retrieval of the global and regional water budgets from space-borne and ground-based gravity surveys. Water is mankind’s most critical natural resource, but it is being heavily used throughout the globe. The aim of this paper is to outline...... the HYDROGRAV project dealing with improving large scale hydrological model with time variable gravity observations. Also preliminary HYDROGRAV investigationsa of terrestrial water storage variations in the Okavango delta in Botswana are presented. Data from 4 years of satellite altimetry, GRACE derived TWS...... and GLDAS hydrological model all show a clear annual variation corresponding to the well known seasonality of the delta. However, they also all show an increasing trend in the amount of water storage in the region over the last 4 years....

  18. Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions

    International Nuclear Information System (INIS)

    1993-01-01

    This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake's ground motion is a function of the earthquake's magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. This document, Volume II, contains Appendices 2, 3, 5, 6, and 7 covering the following topics: Eastern North American Empirical Ground Motion Data; Examination of Variance of Seismographic Network Data; Soil Amplification and Vertical-to-Horizontal Ratios from Analysis of Strong Motion Data From Active Tectonic Regions; Revision and Calibration of Ou and Herrmann Method; Generalized Ray Procedure for Modeling Ground Motion Attenuation; Crustal Models for Velocity Regionalization; Depth Distribution Models; Development of Generic Site Effects Model; Validation and Comparison of One-Dimensional Site Response Methodologies; Plots of Amplification Factors; Assessment of Coupling Between Vertical ampersand Horizontal Motions in Nonlinear Site Response Analysis; and Modeling of Dynamic Soil Properties

  19. Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions. Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    1993-03-18

    This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake`s ground motion is a function of the earthquake`s magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. This document, Volume II, contains Appendices 2, 3, 5, 6, and 7 covering the following topics: Eastern North American Empirical Ground Motion Data; Examination of Variance of Seismographic Network Data; Soil Amplification and Vertical-to-Horizontal Ratios from Analysis of Strong Motion Data From Active Tectonic Regions; Revision and Calibration of Ou and Herrmann Method; Generalized Ray Procedure for Modeling Ground Motion Attenuation; Crustal Models for Velocity Regionalization; Depth Distribution Models; Development of Generic Site Effects Model; Validation and Comparison of One-Dimensional Site Response Methodologies; Plots of Amplification Factors; Assessment of Coupling Between Vertical & Horizontal Motions in Nonlinear Site Response Analysis; and Modeling of Dynamic Soil Properties.

  20. Ground-Water Quality Data in the Coastal Los Angeles Basin Study Unit, 2006: Results from the California GAMA Program

    Science.gov (United States)

    Mathany, Timothy M.; Land, Michael; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 860 square-mile Coastal Los Angeles Basin study unit (CLAB) was investigated from June to November of 2006 as part of the Statewide Basin Assessment Project of the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment was developed in response to the Ground-Water Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Coastal Los Angeles Basin study was designed to provide a spatially unbiased assessment of raw ground-water quality within CLAB, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 69 wells in Los Angeles and Orange Counties. Fifty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (?grid wells?). Fourteen additional wells were selected to evaluate changes in ground-water chemistry or to gain a greater understanding of the ground-water quality within a specific portion of the Coastal Los Angeles Basin study unit ('understanding wells'). Ground-water samples were analyzed for: a large number of synthetic organic constituents [volatile organic compounds (VOCs), gasoline oxygenates and their degradates, pesticides, polar pesticides, and pesticide degradates, pharmaceutical compounds, and potential wastewater-indicators]; constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), 1,4-dioxane, and 1,2,3-trichloropropane (1,2,3-TCP)]; inorganic constituents that can occur naturally [nutrients, major and minor ions, and trace elements]; radioactive constituents [gross-alpha and gross-beta radiation, radium isotopes, and radon-222]; and microbial indicators. Naturally occurring isotopes [stable isotopic ratios of hydrogen and oxygen, and activities of tritium and carbon-14

  1. Ground-Water Quality Data in the Santa Clara River Valley Study Unit, 2007: Results from the California GAMA Program

    Science.gov (United States)

    Montrella, Joseph; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 460-square-mile Santa Clara River Valley study unit (SCRV) was investigated from April to June 2007 as part of the statewide Priority Basin project of the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of the quality of raw ground water used for public water supplies within SCRV, and to facilitate a statistically consistent basis for comparing water quality throughout California. Fifty-seven ground-water samples were collected from 53 wells in Ventura and Los Angeles Counties. Forty-two wells were selected using a randomized grid-based method to provide statistical representation of the study area (grid wells). Eleven wells (understanding wells) were selected to further evaluate water chemistry in particular parts of the study area, and four depth-dependent ground-water samples were collected from one of the eleven understanding wells to help understand the relation between water chemistry and depth. The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, potential wastewater-indicator compounds, and pharmaceutical compounds), a constituent of special interest (perchlorate), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial constituents. Naturally occurring isotopes (tritium, carbon-13, carbon-14 [abundance], stable isotopes of hydrogen and oxygen in water, stable isotopes of nitrogen and oxygen in nitrate, chlorine-37, and bromine-81), and dissolved noble gases also were measured to help identify the source

  2. Characteristic mega-basin water storage behavior using GRACE.

    Science.gov (United States)

    Reager, J T; Famiglietti, James S

    2013-06-01

    [1] A long-standing challenge for hydrologists has been a lack of observational data on global-scale basin hydrological behavior. With observations from NASA's Gravity Recovery and Climate Experiment (GRACE) mission, hydrologists are now able to study terrestrial water storage for large river basins (>200,000 km 2 ), with monthly time resolution. Here we provide results of a time series model of basin-averaged GRACE terrestrial water storage anomaly and Global Precipitation Climatology Project precipitation for the world's largest basins. We address the short (10 year) length of the GRACE record by adopting a parametric spectral method to calculate frequency-domain transfer functions of storage response to precipitation forcing and then generalize these transfer functions based on large-scale basin characteristics, such as percent forest cover and basin temperature. Among the parameters tested, results show that temperature, soil water-holding capacity, and percent forest cover are important controls on relative storage variability, while basin area and mean terrain slope are less important. The derived empirical relationships were accurate (0.54 ≤  E f  ≤ 0.84) in modeling global-scale water storage anomaly time series for the study basins using only precipitation, average basin temperature, and two land-surface variables, offering the potential for synthesis of basin storage time series beyond the GRACE observational period. Such an approach could be applied toward gap filling between current and future GRACE missions and for predicting basin storage given predictions of future precipitation.

  3. Global evaluation of new GRACE mascon products for hydrologic applications

    Science.gov (United States)

    Scanlon, Bridget R.; Zhang, Zizhan; Save, Himanshu; Wiese, David N.; Landerer, Felix W.; Long, Di; Longuevergne, Laurent; Chen, Jianli

    2016-12-01

    Recent developments in mascon (mass concentration) solutions for GRACE (Gravity Recovery and Climate Experiment) satellite data have significantly increased the spatial localization and amplitude of recovered terrestrial Total Water Storage anomalies (TWSA); however, land hydrology applications have been limited. Here we compare TWSA from April 2002 through March 2015 from (1) newly released GRACE mascons from the Center for Space Research (CSR-M) with (2) NASA JPL mascons (JPL-M), and with (3) CSR Tellus gridded spherical harmonics rescaled (sf) (CSRT-GSH.sf) in 176 river basins, ˜60% of the global land area. Time series in TWSA mascons (CSR-M and JPL-M) and spherical harmonics are highly correlated (rank correlation coefficients mostly >0.9). The signal from long-term trends (up to ±20 mm/yr) is much less than that from seasonal amplitudes (up to 250 mm). Net long-term trends, summed over all 176 basins, are similar for CSR and JPL mascons (66-69 km3/yr) but are lower for spherical harmonics (˜14 km3/yr). Long-term TWSA declines are found mostly in irrigated basins (-41 to -69 km3/yr). Seasonal amplitudes agree among GRACE solutions, increasing confidence in GRACE-based seasonal fluctuations. Rescaling spherical harmonics significantly increases agreement with mascons for seasonal fluctuations, but less for long-term trends. Mascons provide advantages relative to spherical harmonics, including (1) reduced leakage from land to ocean increasing signal amplitude, and (2) application of geophysical data constraints during processing with little empirical postprocessing requirements, making it easier for nongeodetic users. Results of this product intercomparison should allow hydrologists to better select suitable GRACE solutions for hydrologic applications.

  4. Ground-Water Quality Data in the Southeast San Joaquin Valley, 2005-2006 - Results from the California GAMA Program

    Science.gov (United States)

    Burton, Carmen A.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 3,800 square-mile Southeast San Joaquin Valley study unit (SESJ) was investigated from October 2005 through February 2006 as part of the Priority Basin Assessment Project of Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment project was developed in response to the Ground-Water Quality Monitoring Act of 2001 and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The SESJ study was designed to provide a spatially unbiased assessment of raw ground-water quality within SESJ, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 99 wells in Fresno, Tulare, and Kings Counties, 83 of which were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and 16 of which were sampled to evaluate changes in water chemistry along ground-water flow paths or across alluvial fans (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine, and 1,2,3-trichloropropane), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected at approximately 10 percent of the wells, and the results

  5. Ground-Water Quality Data in the Southern Sacramento Valley, California, 2005 - Results from the California GAMA Program

    Science.gov (United States)

    Milby Dawson, Barbara J.; Bennett, George L.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 2,100 square-mile Southern Sacramento Valley study unit (SSACV) was investigated from March to June 2005 as part of the Statewide Basin Assessment Project of Ground-Water Ambient Monitoring and Assessment (GAMA) Program. This study was designed to provide a spatially unbiased assessment of raw ground-water quality within SSACV, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 83 wells in Placer, Sacramento, Solano, Sutter, and Yolo Counties. Sixty-seven of the wells were selected using a randomized grid-based method to provide statistical representation of the study area. Sixteen of the wells were sampled to evaluate changes in water chemistry along ground-water flow paths. Four additional samples were collected at one of the wells to evaluate water-quality changes with depth. The GAMA Statewide Basin Assessment project was developed in response to the Ground-Water Quality Monitoring Act of 2001 and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The ground-water samples were analyzed for a large number of man-made organic constituents (volatile organic compounds [VOCs], pesticides and pesticide degradates, pharmaceutical compounds, and wastewater-indicator constituents), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, matrix spikes

  6. Ground-Water Quality Data in the Central Sierra Study Unit, 2006 - Results from the California GAMA Program

    Science.gov (United States)

    Ferrari, Matthew J.; Fram, Miranda S.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 950 square kilometer (370 square mile) Central Sierra study unit (CENSIE) was investigated in May 2006 as part of the Priority Basin Assessment project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Assessment project was developed in response to the Ground-Water Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). This study was designed to provide a spatially unbiased assessment of the quality of raw ground water used for drinking-water supplies within CENSIE, and to facilitate statistically consistent comparisons of ground-water quality throughout California. Samples were collected from thirty wells in Madera County. Twenty-seven of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and three were selected to aid in evaluation of specific water-quality issues (understanding wells). Ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], gasoline oxygenates and degradates, pesticides and pesticide degradates), constituents of special interest (N-nitrosodimethylamine, perchlorate, and 1,2,3-trichloropropane), naturally occurring inorganic constituents [nutrients, major and minor ions, and trace elements], radioactive constituents, and microbial indicators. Naturally occurring isotopes [tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon], and dissolved noble gases also were measured to help identify the sources and ages of the sampled ground water. In total, over 250 constituents and water-quality indicators were investigated. Quality-control samples (blanks, replicates, and samples for matrix spikes) were collected at approximately one-sixth of the wells, and

  7. Ground-Water Quality Data in the Kern County Subbasin Study Unit, 2006 - Results from the California GAMA Program

    Science.gov (United States)

    Shelton, Jennifer L.; Pimentel, Isabel; Fram, Miranda S.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 3,000 square-mile Kern County Subbasin study unit (KERN) was investigated from January to March, 2006, as part of the Priority Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Assessment project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The Kern County Subbasin study was designed to provide a spatially unbiased assessment of raw (untreated) ground-water quality within KERN, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 50 wells within the San Joaquin Valley portion of Kern County. Forty-seven of the wells were selected using a randomized grid-based method to provide a statistical representation of the ground-water resources within the study unit. Three additional wells were sampled to aid in the evaluation of changes in water chemistry along regional ground-water flow paths. The ground-water samples were analyzed for a large number of man-made organic constituents (volatile organic compounds [VOCs], pesticides, and pesticide degradates), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon) and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, and laboratory matrix spikes) were collected and analyzed at approximately 10 percent of

  8. Ground-Water Quality Data in the Middle Sacramento Valley Study Unit, 2006 - Results from the California GAMA Program

    Science.gov (United States)

    Schmitt, Stephen J.; Fram, Miranda S.; Milby Dawson, Barbara J.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 3,340 square mile Middle Sacramento Valley study unit (MSACV) was investigated from June through September, 2006, as part of the California Groundwater Ambient Monitoring and Assessment (GAMA) program. The GAMA Priority Basin Assessment project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Middle Sacramento Valley study was designed to provide a spatially unbiased assessment of raw ground-water quality within MSACV, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 108 wells in Butte, Colusa, Glenn, Sutter, Tehama, Yolo, and Yuba Counties. Seventy-one wells were selected using a randomized grid-based method to provide statistical representation of the study unit (grid wells), 15 wells were selected to evaluate changes in water chemistry along ground-water flow paths (flow-path wells), and 22 were shallow monitoring wells selected to assess the effects of rice agriculture, a major land use in the study unit, on ground-water chemistry (RICE wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], gasoline oxygenates and degradates, pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon), and dissolved noble gases also were measured to help identify the sources and ages of the sampled ground water. Quality-control samples (blanks

  9. Ground-Water Quality Data in the Coachella Valley Study Unit, 2007: Results from the California GAMA Program

    Science.gov (United States)

    Goldrath, Dara A.; Wright, Michael T.; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 820 square-mile Coachella Valley Study Unit (COA) was investigated during February and March 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of raw ground water used for public-water supplies within the Coachella Valley, and to facilitate statistically consistent comparisons of ground-water quality throughout California. Samples were collected from 35 wells in Riverside County. Nineteen of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells). Sixteen additional wells were sampled to evaluate changes in water chemistry along selected ground-water flow paths, examine land use effects on ground-water quality, and to collect water-quality data in areas where little exists. These wells were referred to as 'understanding wells'. The ground-water samples were analyzed for a large number of organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, pharmaceutical compounds, and potential wastewater-indicator compounds), constituents of special interest (perchlorate and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (uranium, tritium, carbon-14, and stable isotopes of hydrogen, oxygen, and boron), and dissolved noble gases (the last in collaboration with Lawrence Livermore National Laboratory) also were measured to help identify the source and age of the sampled

  10. Effect of the Programmed Nutrition Beef Program on moisture retention of cooked ground beef patties and enhanced strip loins.

    Science.gov (United States)

    2015-02-01

    This study evaluated the influence of the Programmed Nutrition Beef Program and exogenous growth promotants (ExGP) on water holding capacity characteristics of enhanced beef strip loins. Sixty, frozen strip loins, arranged in a 2 × 2 factorial treatment arrangement with dietary program serving as the first factor and use of ExGP as the second factor, were thawed, injected with an enhancement solution, and stored for 7 days. Loins from ExGP cattle possessed the ability to bind more (P water before pumping and bind less (P water after pumping and storage. Loin pH across treatments was similar (P > 0.10) before injection, but increased post-injection and after storage (P 0.10). The Programmed Nutrition Beef Program and use of ExGPs minimally impacted water holding capacity of enhanced frozen/thawed beef strip loins.

  11. Shuttle Ground Support Equipment (GSE) T-0 Umbilical to Space Shuttle Program (SSP) Flight Elements Consultation

    Science.gov (United States)

    Wilson, Timmy R.; Kichak, Robert A.; McManamen, John P.; Kramer-White, Julie; Raju, Ivatury S.; Beil, Robert J.; Weeks, John F.; Elliott, Kenny B.

    2009-01-01

    The NASA Engineering and Safety Center (NESC) was tasked with assessing the validity of an alternate opinion that surfaced during the investigation of recurrent failures at the Space Shuttle T-0 umbilical interface. The most visible problem occurred during the Space Transportation System (STS)-112 launch when pyrotechnics used to separate Solid Rocket Booster (SRB) Hold-Down Post (HDP) frangible nuts failed to fire. Subsequent investigations recommended several improvements to the Ground Support Equipment (GSE) and processing changes were implemented, including replacement of ground-half cables and connectors between flights, along with wiring modifications to make critical circuits quad-redundant across the interface. The alternate opinions maintained that insufficient data existed to exonerate the design, that additional data needed to be gathered under launch conditions, and that the interface should be further modified to ensure additional margin existed to preclude failure. The results of the assessment are contained in this report.

  12. Aircraft and ground vehicle friction correlation test results obtained under winter runway conditions during joint FAA/NASA Runway Friction Program

    Science.gov (United States)

    Yager, Thomas J.; Vogler, William A.; Baldasare, Paul

    1988-01-01

    Aircraft and ground vehicle friction data collected during the Joint FAA/NASA Runway Friction Program under winter runway conditions are discussed and test results are summarized. The relationship between the different ground vehicle friction measurements obtained on compacted snow- and ice-covered conditions is defined together with the correlation to aircraft tire friction performance under similar runway conditions.

  13. Development of methodology and computer programs for the ground response spectrum and the probabilistic seismic hazard analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joon Kyoung [Semyung Univ., Research Institute of Industrial Science and Technol , Jecheon (Korea, Republic of)

    1996-12-15

    Objective of this study is to investigate and develop the methodologies and corresponding computer codes, compatible to the domestic seismological and geological environments, for estimating ground response spectrum and probabilistic seismic hazard. Using the PSHA computer program, the Cumulative Probability Functions(CPDF) and Probability Functions (PDF) of the annual exceedence have been investigated for the analysis of the uncertainty space of the annual probability at ten interested seismic hazard levels (0.1 g to 0.99 g). The cumulative provability functions and provability functions of the annual exceedence have been also compared to those results from the different input parameter spaces.

  14. Ground-Water Quality Data in the Southern Sierra Study Unit, 2006 - Results from the California GAMA Program

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2007-01-01

    Ground-water quality in the approximately 1,800 square-mile Southern Sierra study unit (SOSA) was investigated in June 2006 as part of the Statewide Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Southern Sierra study was designed to provide a spatially unbiased assessment of raw ground-water quality within SOSA, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from fifty wells in Kern and Tulare Counties. Thirty-five of the wells were selected using a randomized grid-based method to provide statistical representation of the study area, and fifteen were selected to evaluate changes in water chemistry along ground-water flow paths. The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates, pharmaceutical compounds, and wastewater-indicator compounds], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), and 1,2,3-trichloropropane (1,2,3-TCP)], naturally occurring inorganic constituents [nutrients, major and minor ions, and trace elements], radioactive constituents, and microbial indicators. Naturally occurring isotopes [tritium, and carbon-14, and stable isotopes of hydrogen and oxygen in water], and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, and samples for matrix spikes) were collected for approximately one-eighth of the wells, and the results for these samples were used to evaluate the quality of the data for the ground-water samples. Assessment of the

  15. Ground-Water Quality Data in the Central Eastside San Joaquin Basin 2006: Results from the California GAMA Program

    Science.gov (United States)

    Landon, Matthew K.; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 1,695-square-mile Central Eastside study unit (CESJO) was investigated from March through June 2006 as part of the Statewide Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The study was designed to provide a spatially unbiased assessment of raw ground-water quality within CESJO, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 78 wells in Merced and Stanislaus Counties. Fifty-eight of the 78 wells were selected using a randomized grid-based method to provide statistical representation of the study unit (grid wells). Twenty of the wells were selected to evaluate changes in water chemistry along selected lateral or vertical ground-water flow paths in the aquifer (flow-path wells). The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), gasoline oxygenates and their degradates, pesticides and pesticide degradates], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), and 1,2,3-trichloropropane (1,2,3-TCP)], inorganic constituents that can occur naturally [nutrients, major and minor ions, and trace elements], radioactive constituents, and microbial indicators. Naturally occurring isotopes [tritium, carbon-14, and uranium isotopes and stable isotopes of hydrogen, oxygen, nitrogen, sulfur, and carbon], and dissolved noble and other gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected

  16. Ground-Water Quality Data in the San Francisco Bay Study Unit, 2007: Results from the California GAMA Program

    Science.gov (United States)

    Ray, Mary C.; Kulongoski, Justin T.; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 620-square-mile San Francisco Bay study unit (SFBAY) was investigated from April through June 2007 as part of the Priority Basin project of the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The study was designed to provide a spatially unbiased assessment of raw ground-water quality, as well as a statistically consistent basis for comparing water quality throughout California. Samples in SFBAY were collected from 79 wells in San Francisco, San Mateo, Santa Clara, Alameda, and Contra Costa Counties. Forty-three of the wells sampled were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells). Thirty-six wells were sampled to aid in evaluation of specific water-quality issues (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOC], pesticides and pesticide degradates, pharmaceutical compounds, and potential wastewater-indicator compounds), constituents of special interest (perchlorate and N-nitrosodimethylamine [NDMA]), naturally occurring inorganic constituents (nutrients, major and minor ions, trace elements, chloride and bromide isotopes, and uranium and strontium isotopes), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, carbon-14 isotopes, and stable isotopes of hydrogen, oxygen, nitrogen, boron, and carbon), and dissolved noble gases (noble gases were analyzed in collaboration with Lawrence Livermore National Laboratory) also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blank samples

  17. Reliability program plan for the Isotope Brayton Ground Demonstration System (phase I)

    International Nuclear Information System (INIS)

    1975-01-01

    The reliability and quality assurance organizational relationships, the methods to be used, the tasks to be completed, and the documentation to be published are presented. The total program is intended to provide the necessary reliability and quality assurance associated with the design, fabrication, and testing of the GDS. It is consistent with the general objectives of the ERDA Quality Assurance (QA) program requirements document ''SNS-1'' dated April 1972 and reliability program requirements document ''SNS-2'' dated 17 June 1974 but has been specifically modified for the GDS with the intent of establishing background data for the subsequent Phase II effort

  18. GRACE-derived terrestrial water storage depletion associated with the 2003 European heat wave

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Seneviratne, S.I.; Hinderer, J.

    2005-01-01

    water storage depletion observed from GRACE can be related to the record-breaking heat wave that occurred in central Europe in 2003. We validate the measurements from GRACE using two independent hydrological estimates and direct gravity observations from superconducting gravimeters in Europe. All...... datasets agree well with the GRACE measurements despite the disparity of the employed information; the difference between datasets tends to be within GRACE margin of error. The April-to-August terrestrial water storage depletion is found to be significantly larger in 2003 than in 2002 from both models......The GRACE twin satellites reveal large inter-annual terrestrial water-storage variations between 2002 and 2003 for central Europe. GRACE observes a negative trend in regional water storage from 2002 to 2003 peaking at -7.8 cm in central Europe with an accuracy of 1 cm. The 2003 excess terrestrial...

  19. A hardware-in-the-loop simulation program for ground-based radar

    Science.gov (United States)

    Lam, Eric P.; Black, Dennis W.; Ebisu, Jason S.; Magallon, Julianna

    2011-06-01

    A radar system created using an embedded computer system needs testing. The way to test an embedded computer system is different from the debugging approaches used on desktop computers. One way to test a radar system is to feed it artificial inputs and analyze the outputs of the radar. More often, not all of the building blocks of the radar system are available to test. This will require the engineer to test parts of the radar system using a "black box" approach. A common way to test software code on a desktop simulation is to use breakpoints so that is pauses after each cycle through its calculations. The outputs are compared against the values that are expected. This requires the engineer to use valid test scenarios. We will present a hardware-in-the-loop simulator that allows the embedded system to think it is operating with real-world inputs and outputs. From the embedded system's point of view, it is operating in real-time. The hardware in the loop simulation is based on our Desktop PC Simulation (PCS) testbed. In the past, PCS was used for ground-based radars. This embedded simulation, called Embedded PCS, allows a rapid simulated evaluation of ground-based radar performance in a laboratory environment.

  20. Seasonal effects on ground water chemistry of the Ouachita Mountains. National Uranium Resource Evaluation Program

    International Nuclear Information System (INIS)

    Steele, K.F.; Fay, W.M.; Cavendor, P.N.

    1982-08-01

    Samples from 13 ground water sites (10 springs and 3 wells) in the Ouachita Mountains were collected nine times during a 16-month period. Daily sampling of six sites was carried out over an 11-day period, with rain during this period. Finally, hourly sampling was conducted at a single site over a 7-hour period. The samples were analyzed for pH, conductivity, temperature, total alkalinity, nitrate, ammonia, sulfate, phosphate, chloride, silica, Na, K, Li, Ca, Mg, Sr, Ba, Fe, Mn, Zn, Cu, Co, Ni, Pb, Hg, Br, F, V, Al, Dy, and U. Despite the dry season during late summer, and wet seasons during late spring and late fall in the Ouachita Mountain region, there was no significant change in the ground water chemistry with season. Likewise, there was no significant change due to rain storm events (daily sampling) or hourly sampling. The report is issued in draft form, without detailed technical and copy editing. This was done to make the report available to the public before the end of the National Uranium Resource Evaluation. 9 figures, 19 tables

  1. Shaping a valued learning journey: Student satisfaction with learning in undergraduate nursing programs, a grounded theory study.

    Science.gov (United States)

    Smith, Morgan R; Grealish, Laurie; Henderson, Saras

    2018-05-01

    Student satisfaction is a quality measure of increasing importance in undergraduate programs, including nursing programs. To date theories of student satisfaction have focused primarily on students' perceptions of the educational environment rather than their perceptions of learning. Understanding how students determine satisfaction with learning is necessary to facilitate student learning across a range of educational contexts and meet the expectations of diverse stakeholders. To understand undergraduate nursing students' satisfaction with learning. Constructivist grounded theory methodology was used to identify how nursing students determined satisfaction with learning. Two large, multi-campus, nursing schools in Australia. Seventeen demographically diverse undergraduate nursing students studying different stages of a three year program participated in the study. Twenty nine semi-structured interviews were conducted. Students were invited to describe situations where they had been satisfied or dissatisfied with their learning. A constructivist grounded theory approach was used to analyse the data. Students are satisfied with learning when they shape a valued learning journey that accommodates social contexts of self, university and nursing workplace. The theory has three phases. Phase 1 - orienting self to valued learning in the pedagogical landscape; phase 2 - engaging with valued learning experiences across diverse pedagogical terrain; and phase 3 - recognising valued achievement along the way. When students experience a valued learning journey they are satisfied with their learning. Student satisfaction with learning is unique to the individual, changes over time and maybe transient or sustained, mild or intense. Finding from the research indicate areas where nurse academics may facilitate satisfaction with learning in undergraduate nursing programs while mindful of the expectations of other stakeholders such as the university, nurse registering authorities

  2. Status of GRACE system - automatic computation of cross sections

    International Nuclear Information System (INIS)

    Fujimoto, J.; Ishikawa, T.; Kawabata, S.; Kurihara, Y.; Shimizu, Y.; Kato, K.; Nakazawa, N.; Kaneko, T.; Tanaka, H.

    1995-01-01

    Automated system is an essential tool for high-energy physics and GRACE system for tree processes makes it possible to calculate cross sections for complicated processes exactly. To check the output of the automatic system we make comparison between Hooft-t-Feynman gauge and unitary gauge, the exchange of external particles, and we check the independence of UV divergence parameter and that of IR divergence parameter

  3. Assessment of 3D hydrologic deformation using GRACE and GPS

    Science.gov (United States)

    Watson, C. S.; Tregoning, P.; Fleming, K.; Burgette, R. J.; Featherstone, W. E.; Awange, J.; Kuhn, M.; Ramillien, G.

    2009-12-01

    Hydrological processes cause variations in gravitational potential and surface deformations, both of which are detectable with ever increasing precision using space geodetic techniques. By comparing the elastic deformation computed from continental water load estimates derived from the Gravity Recovery and Climate Experiment (GRACE), with three-dimensional surface deformation derived from GPS observations, there is clear potential to better understand global to regional hydrological processes, in addition to acquiring further insight into the systematic error contributions affecting each space geodetic technique. In this study, we compare elastic deformation derived from water load estimates taken from the CNES, CSR, GFZ and JPL time variable GRACE fields. We compare these surface displacements with those derived at a global network of GPS sites that have been homogeneously reprocessed in the GAMIT/GLOBK suite. We extend our comparison to include a series of different GPS solutions, with each solution only subtly different based on the methodology used to down weight the height component in realizing site coordinates on the terrestrial reference frame. Each of the GPS solutions incorporate modeling of atmospheric loading and utilization of the VMF1 and a priori zenith hydrostatic delays derived via ray tracing through ECMWF meteorological fields. The agreement between GRACE and GPS derived deformations is not limited to the vertical component, with excellent agreement in the horizontal component across areas where large hydrologic signals occur over broad spatial scales (with correlation in horizontal components as high as 0.9). Agreement is also observed at smaller scales, including across Europe. These comparisons assist in understanding the magnitude of current error contributions within both space geodetic techniques. With the emergence of homogeneously reprocessed GPS time series spanning the GRACE mission, this technique offers one possible means of

  4. Evaluation of multiple satellite evaporation products in two dryland regions using GRACE

    KAUST Repository

    Lopez, Oliver

    2015-12-01

    Remote sensing has become a valuable tool for monitoring the water cycle variables in areas that lack the availability of ground-based measurements. Integrating multiple remote sensing-based estimates of evaporation, precipitation, and the terrestrial water storage changes with local measurements of streamflow into a consistent estimate of the regional water budget is a challenge, due to the scale mismatch among the retrieved variables. Evapotranspiration, including soil evaporation, interception losses and canopy transpiration, has received special focus in a number of recent studies that aim to provide global or regional estimates of evaporation at regular time intervals using a variety of remote sensing input. In arid and semi-arid regions, modeling of evaporation is particularly challenging due to the relatively high role of the soil evaporation component in these regions and the variable nature of rainfall events that drive the evaporation process. In this study, we explore the hydrological consistency of remote sensing products in terms of water budget closure and the correlation among spatial patterns of precipitation (P), evaporation (E) and terrestrial water storage, using P-E as a surrogate of water storage changes, with special attention to the evaporation component. The analysis is undertaken within two dryland regions that have presented recent significant changes in climatology (Murray-Darling Basin in Australia) and water storage (the Saq aquifer in northern Saudi Arabia). Water storage changes were derived from the Gravity Recovery and Climate Experiment (GRACE) spherical harmonic (SH) coefficients. Six remote sensing-based evaporation estimates were subtracted from the Global Precipitation Climatology Project (GPCP)-based precipitation estimates and were compared with GRACE-derived water storage changes. Our results suggest that it is not possible to close the water balance by using satellite data alone, even when adopting a spherical harmonic

  5. Results and Error Estimates from GRACE Forward Modeling over Antarctica

    Science.gov (United States)

    Bonin, Jennifer; Chambers, Don

    2013-04-01

    Forward modeling using a weighted least squares technique allows GRACE information to be projected onto a pre-determined collection of local basins. This decreases the impact of spatial leakage, allowing estimates of mass change to be better localized. The technique is especially valuable where models of current-day mass change are poor, such as over Antarctica. However when tested previously, the least squares technique has required constraints in the form of added process noise in order to be reliable. Poor choice of local basin layout has also adversely affected results, as has the choice of spatial smoothing used with GRACE. To develop design parameters which will result in correct high-resolution mass detection and to estimate the systematic errors of the method over Antarctica, we use a "truth" simulation of the Antarctic signal. We apply the optimal parameters found from the simulation to RL05 GRACE data across Antarctica and the surrounding ocean. We particularly focus on separating the Antarctic peninsula's mass signal from that of the rest of western Antarctica. Additionally, we characterize how well the technique works for removing land leakage signal from the nearby ocean, particularly that near the Drake Passage.

  6. California Drought Recovery Assessment Using GRACE Satellite Gravimetry Information

    Science.gov (United States)

    Love, C. A.; Aghakouchak, A.; Madadgar, S.; Tourian, M. J.

    2015-12-01

    California has been experiencing its most extreme drought in recent history due to a combination of record high temperatures and exceptionally low precipitation. An estimate for when the drought can be expected to end is needed for risk mitigation and water management. A crucial component of drought recovery assessments is the estimation of terrestrial water storage (TWS) deficit. Previous studies on drought recovery have been limited to surface water hydrology (precipitation and/or runoff) for estimating changes in TWS, neglecting the contribution of groundwater deficits to the recovery time of the system. Groundwater requires more time to recover than surface water storage; therefore, the inclusion of groundwater storage in drought recovery assessments is essential for understanding the long-term vulnerability of a region. Here we assess the probability, for varying timescales, of California's current TWS deficit returning to its long-term historical mean. Our method consists of deriving the region's fluctuations in TWS from changes in the gravity field observed by NASA's Gravity Recovery and Climate Experiment (GRACE) satellites. We estimate the probability that meteorological inputs, precipitation minus evaporation and runoff, over different timespans will balance the current GRACE-derived TWS deficit (e.g. in 3, 6, 12 months). This method improves upon previous techniques as the GRACE-derived water deficit comprises all hydrologic sources, including surface water, groundwater, and snow cover. With this empirical probability assessment we expect to improve current estimates of California's drought recovery time, thereby improving risk mitigation.

  7. Inter-comparison of GRACE data over India

    Science.gov (United States)

    Banerjee, Chandan; Kumar, D. Nagesh

    2016-05-01

    The advent of satellite remote sensing and its use in hydrology has facilitated a huge leap in the understanding of the various water resources, its interaction with ecological systems and anthropogenic creations. Recently, NASA and German Aerospace Research Agency-DLR launched the Gravity Recovery and Climate Experiment (GRACE) satellite mission consisting of two satellites. They measure the time varying gravity which gives changes in the distribution of mass on the surface of the earth which after removing atmospheric and oceanic effects is majorly caused by changes in Terrestrial Water Storage (TWS) changes. GRACE data is generally available as spherical harmonic coefficients, which is difficult for hydrologists to understand and interpret. JPL's TELLUS website is now providing gridded global data set in the form of mass anomaly derived from the Level-2 data sets of spherical harmonic coefficients of 3 sources, viz. CSR, GFZ and JPL. Before using these data sets for solving hydrological problems, it is important to understand the differences and similarities between these data sets as direct calibration of GRACE data is not possible. In this study we do an inter-comparison of the Level-3 Release 05 data sets over India. We compare the data sets using Pearson, Spearman and Kendall correlation. CSR and GFZ data sets appear to be closest to each other whereas JPL and GFZ data sets are most different from each other.

  8. Reformation or Revolution? Herman Bavinck and Henri de Lubac on Nature and Grace

    Directory of Open Access Journals (Sweden)

    Parker Gregory W.

    2017-10-01

    Full Text Available Henri de Lubac’s treatment of the relationship between nature and grace will be critiqued by Herman Bavinck’s ‘grace restores nature’ theme. In two significant addresses, Bavinck critiqued a Roman Catholic approach to nature and grace. De Lubac’s influence upon Roman Catholic thinking addressing nature and grace occurred post-Bavinck and has altered Catholic thinking on the subject. Neo-Calvinist scholar, Wolter Huttinga admits that Bavinck and de Lubac offer similar critiques of Roman Catholicism (Huttinga 2014. The question remains then, do Bavinck’s critiques still hold? I propose that Bavinck’s account of grace restores nature still makes valid critiques of a post-Vatican II construction of nature and grace. The paper is broken into three sections: (1 an exploration of de Lubac’s nature and grace theme, (2 the framework of Bavinck’s ‘grace restores nature’ theme, and (3 a Bavinckian critique of de Lubac’s nature and grace theme.

  9. ARMA models for earthquake ground motions. Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Chang, Mark K.; Kwiatkowski, Jan W.; Nau, Robert F.; Oliver, Robert M.; Pister, Karl S.

    1981-02-01

    This report contains an analysis of four major California earthquake records using a class of discrete linear time-domain processes commonly referred to as ARMA (Autoregressive/Moving-Average) models. It has been possible to analyze these different earthquakes, identify the order of the appropriate ARMA model(s), estimate parameters and test the residuals generated by these models. It has also been possible to show the connections, similarities and differences between the traditional continuous models (with parameter estimates based on spectral analyses) and the discrete models with parameters estimated by various maximum likelihood techniques applied to digitized acceleration data in the time domain. The methodology proposed in this report is suitable for simulating earthquake ground motions in the time domain and appears to be easily adapted to serve as inputs for nonlinear discrete time models of structural motions. (author)

  10. DEPDOSE: An interactive, microcomputer based program to calculate doses from exposure to radionuclides deposited on the ground

    International Nuclear Information System (INIS)

    Beres, D.A.; Hull, A.P.

    1991-12-01

    DEPDOSE is an interactive, menu driven, microcomputer based program designed to rapidly calculate committed dose from radionuclides deposited on the ground. The program is designed to require little or no computer expertise on the part of the user. The program consisting of a dose calculation section and a library maintenance section. These selections are available to the user from the main menu. The dose calculation section provides the user with the ability to calculate committed doses, determine the decay time needed to reach a particular dose, cross compare deposition data from separate locations, and approximate a committed dose based on a measured exposure rate. The library maintenance section allows the user to review and update dose modifier data as well as to build and maintain libraries of radionuclide data, dose conversion factors, and default deposition data. The program is structured to provide the user easy access for reviewing data prior to running the calculation. Deposition data can either be entered by the user or imported from other databases. Results can either be displayed on the screen or sent to the printer

  11. Improved estimates of global sea level change from Ice Sheets, glaciers and land water storage using GRACE

    Science.gov (United States)

    Velicogna, I.; Hsu, C. W.; Ciraci, E.; Sutterley, T. C.

    2015-12-01

    We use observations of time variable gravity from GRACE to estimate mass changes for the Antarctic and Greenland Ice Sheets, the Glaciers and Ice Caps (GIC) and land water storage for the time period 2002-2015 and evaluate their total contribution to sea level. We calculate regional sea level changes from these present day mass fluxes using an improved scaling factor for the GRACE data that accounts for the spatial and temporal variability of the observed signal. We calculate a separate scaling factor for the annual and the long-term components of the GRACE signal. To estimate the contribution of the GIC, we use a least square mascon approach and we re-analyze recent inventories to optimize the distribution of mascons and recover the GRACE signal more accurately. We find that overall, Greenland controls 43% of the global trend in eustatic sea level rise, 16% for Antarctica and 29% for the GIC. The contribution from the GIC is dominated by the mass loss of the Canadian Arctic Archipelago, followed by Alaska, Patagonia and the High Mountains of Asia. We report a marked increase in mass loss for the Canadian Arctic Archipelago. In Greenland, following the 2012 high summer melt, years 2013 and 2014 have slowed down the increase in mass loss, but our results will be updated with summer 2015 observations at the meeting. In Antarctica, the mass loss is still on the rise with increased contributions from the Amundsen Sea sector and surprisingly from the Wilkes Land sector of East Antarctica, including Victoria Land. Conversely, the Queen Maud Land sector experienced a large snowfall in 2009-2013 and has now resumed to a zero mass gain since 2013. We compare sea level changes from these GRACE derived mass fluxes after including the atmospheric and ocean loading signal with sea level change from satellite radar altimetry (AVISO) corrected for steric signal of the ocean using Argo measurements and find an excellent agreement in amplitude, phase and trend in these estimates

  12. Field manual for ground water reconnaissance. Savannah River Laboratory National Uranium Resource Evaluation Program

    International Nuclear Information System (INIS)

    Ferguson, R.B.; Price, V.; Baucom, E.I.

    1977-01-01

    A manual is presented that is intended to direct and coordinate field operations, site selection, groundwater sample collection, and information codes for the Savannah River Laboratory (SRL) contribution to the National Uranium Resource Evaluation (NURE) program. The manual provides public relations information for field sampling teams as well as technical direction

  13. U.S. Army’s Ground Vehicle Energy Storage R&D Programs & Goals

    Science.gov (United States)

    2010-11-10

    STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES Briefing to ARPA-E BEEST Meeting 14. ABSTRACT NA 15...Program Collaboration & DOD Customers DOE Material Developers Battery Developers ANL USABC National Labs Universities Industrial Developers...qualification for military lead acid batteries; 6 water baths, 31 circuits, 1 thermal chamber • Electrochemical Research & Analysis Lab (EARL

  14. Recovery Act: Tennessee Energy Efficient Schools Initiative Ground Source Heat Pump Program

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Terry [Townsend Engineering, Inc., Davenport, IA (United States); Slusher, Scott [Townsend Engineering, Inc., Davenport, IA (United States)

    2017-04-24

    The Tennessee Energy Efficient Schools Initiative (EESI) Hybrid-Water Source Heat Pump (HY-GSHP) Program sought to provide installation costs and operation costs for different Hybrid water source heat pump systems’ configurations so that other State of Tennessee School Districts will have a resource for comparison purposes if considering a geothermal system.

  15. System safety program plan for the Isotope Brayton Ground Demonstration System (phase I)

    International Nuclear Information System (INIS)

    1976-01-01

    The safety engineering effort to be undertaken in achieving an acceptable level of safety in the Brayton Isotope Power System (BIPS) development program is discussed. The safety organizational relationships, the methods to be used, the tasks to be completed, and the documentation to be published are described. The plan will be updated periodically as the need arises

  16. A Grounded Theory of Professional Learning in an Authentic Online Professional Development Program

    Science.gov (United States)

    Teräs, Hanna; Kartoglu, Umit

    2017-01-01

    Online professional development (OPD) programs have become increasingly popular. However, participating in professional development does not always lead to profound professional learning. Previous research endeavours have often focussed on measuring user acceptance or on comparing the effectiveness of OPD with a face-to-face delivery, but there is…

  17. Long-term ground-water monitoring program and performance-evaluation plan for the extraction system at the former Nike Missile Battery Site, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Senus, Michael P.; Tenbus, Frederick J.

    2000-01-01

    This report presents lithologic and ground-water-quality data collected during April and May 2000 in the remote areas of the tidal wetland of West Branch Canal Creek, Aberdeen Proving Ground, Maryland. Contamination of the Canal Creek aquifer with volatile organic compounds has been documented in previous investigations of the area. This study was conducted to investigate areas that were previously inaccessible because of deep mud and shallow water, and to support ongoing investigations of the fate and transport of volatile organic compounds in the Canal Creek aquifer. A unique vibracore drill rig mounted on a hovercraft was used for drilling and ground-water sampling. Continuous cores of the wetland sediment and of the Canal Creek aquifer were collected at five sites. Attempts to sample ground water were made by use of a continuous profiler at 12 sites, without well installation, at a total of 81 depths within the aquifer. Of those 81 attempts, only 34 sampling depths produced enough water to collect samples. Ground-water samples from two sites had the highest concentrations of volatile organic compounds?with total volatile organic compound concentrations in the upper part of the aquifer ranging from about 15,000 to 50,000 micrograms per liter. Ground-water samples from five sites had much lower total volatile organic compound concentrations (95 to 2,100 micrograms per liter), whereas two sites were essentially not contaminated, with total volatile organic compound concentrations less than or equal to 5 micrograms per liter.

  18. Grace under Fire: Sociocultural Competency Training.

    Science.gov (United States)

    Avery, Wayne W.; Bawtenheimer, Pat; Pearson, Hilary; Westwood, Dianne

    2001-01-01

    Employers want employees who can communicate effectively, work as part of a team, and think on their feet. To help students acquire these qualities, the faculty of health sciences and counseling at Vancouver Community College integrated a sociocultural training model into their human relations programs. Evaluations indicate that students'…

  19. New advanced netted ground based and topside radio diagnostics for Space Weather Program

    Science.gov (United States)

    Rothkaehl, Hanna; Krankowski, Andrzej; Morawski, Marek; Atamaniuk, Barbara; Zakharenkova, Irina; Cherniak, Iurii

    2014-05-01

    To give a more detailed and complete understanding of physical plasma processes that govern the solar-terrestrial space, and to develop qualitative and quantitative models of the magnetosphere-ionosphere-thermosphere coupling, it is necessary to design and build the next generation of instruments for space diagnostics and monitoring. Novel ground- based wide-area sensor networks, such as the LOFAR (Low Frequency Array) radar facility, comprising wide band, and vector-sensing radio receivers and multi-spacecraft plasma diagnostics should help solve outstanding problems of space physics and describe long-term environmental changes. The LOw Frequency ARray - LOFAR - is a new fully digital radio telescope designed for frequencies between 30 MHz and 240 MHz located in Europe. The three new LOFAR stations will be installed until summer 2015 in Poland. The LOFAR facilities in Poland will be distributed among three sites: Lazy (East of Krakow), Borowiec near Poznan and Baldy near Olsztyn. All they will be connected via PIONIER dedicated links to Poznan. Each site will host one LOFAR station (96 high-band+96 low-band antennas). They will most time work as a part of European network, however, when less charged, they can operate as a national network The new digital radio frequency analyzer (RFA) on board the low-orbiting RELEC satellite was designed to monitor and investigate the ionospheric plasma properties. This two-point ground-based and topside ionosphere-located space plasma diagnostic can be a useful new tool for monitoring and diagnosing turbulent plasma properties. The RFA on board the RELEC satellite is the first in a series of experiments which is planned to be launched into the near-Earth environment. In order to improve and validate the large scales and small scales ionospheric structures we will used the GPS observations collected at IGS/EPN network employed to reconstruct diurnal variations of TEC using all satellite passes over individual GPS stations and the

  20. Grounding Teacher Education in Practice around the World: An Examination of Teacher Education Coursework in Teacher Education Programs in Finland, Norway, and the United States

    Science.gov (United States)

    Jenset, Inga Staal; Klette, Kirsti; Hammerness, Karen

    2018-01-01

    Worldwide, teacher educators and policy makers have called for teacher preparation that is more deeply linked to practice. Yet we know little about how such linkages are achieved within different international programs. We examine the degree to which programs provide opportunities to learn that are grounded in practice, during university…

  1. Safeguarding Self-Governance: A Grounded Theory of Older Patients’ Pattern of Behavior in Relation to their Relatives in Fast-track Programs

    DEFF Research Database (Denmark)

    Berthelsen, Connie B.; Frederiksen, Kirsten; Lindhardt Damsgaard, Tove

    2014-01-01

    Abstract The aim of this study was to generate a grounded theory of older patients’ pattern of behavior in relation to their relatives’ involvement in fast-track programs during total joint replacement. Sixteen patients were recruited in orthopedic wards. Data collection included 11 interviews......, shielding, distancing, and masking. Keywords: Fast-track program, grounded theory, older patients, relatives, total joint replacement.......-governance emerged in the analysis as the core category of our theory and pattern of behavior of the older patients in relation to their relatives. The older patients’ main concern was to complete the fast-track program while maintaining autonomy, which they resolved through four strategies of actions: embracing...

  2. Aviation System Capacity Program Terminal Area Productivity Project: Ground and Airborne Technologies

    Science.gov (United States)

    Giulianetti, Demo J.

    2001-01-01

    Ground and airborne technologies were developed in the Terminal Area Productivity (TAP) project for increasing throughput at major airports by safely maintaining good-weather operating capacity during bad weather. Methods were demonstrated for accurately predicting vortices to prevent wake-turbulence encounters and to reduce in-trail separation requirements for aircraft approaching the same runway for landing. Technology was demonstrated that safely enabled independent simultaneous approaches in poor weather conditions to parallel runways spaced less than 3,400 ft apart. Guidance, control, and situation-awareness systems were developed to reduce congestion in airport surface operations resulting from the increased throughput, particularly during night and instrument meteorological conditions (IMC). These systems decreased runway occupancy time by safely and smoothly decelerating the aircraft, increasing taxi speed, and safely steering the aircraft off the runway. Simulations were performed in which optimal trajectories were determined by air traffic control (ATC) and communicated to flight crews by means of Center TRACON Automation System/Flight Management System (CTASFMS) automation to reduce flight delays, increase throughput, and ensure flight safety.

  3. Assimilation of Gridded GRACE Terrestrial Water Storage Estimates in the North American Land Data Assimilation System

    Science.gov (United States)

    Kumar, Sujay V.; Zaitchik, Benjamin F.; Peters-Lidard, Christa D.; Rodell, Matthew; Reichle, Rolf; Li, Bailing; Jasinski, Michael; Mocko, David; Getirana, Augusto; De Lannoy, Gabrielle; hide

    2016-01-01

    The objective of the North American Land Data Assimilation System (NLDAS) is to provide best available estimates of near-surface meteorological conditions and soil hydrological status for the continental United States. To support the ongoing efforts to develop data assimilation (DA) capabilities for NLDAS, the results of Gravity Recovery and Climate Experiment (GRACE) DA implemented in a manner consistent with NLDAS development are presented. Following previous work, GRACE terrestrial water storage (TWS) anomaly estimates are assimilated into the NASA Catchment land surface model using an ensemble smoother. In contrast to many earlier GRACE DA studies, a gridded GRACE TWS product is assimilated, spatially distributed GRACE error estimates are accounted for, and the impact that GRACE scaling factors have on assimilation is evaluated. Comparisons with quality-controlled in situ observations indicate that GRACE DA has a positive impact on the simulation of unconfined groundwater variability across the majority of the eastern United States and on the simulation of surface and root zone soil moisture across the country. Smaller improvements are seen in the simulation of snow depth, and the impact of GRACE DA on simulated river discharge and evapotranspiration is regionally variable. The use of GRACE scaling factors during assimilation improved DA results in the western United States but led to small degradations in the eastern United States. The study also found comparable performance between the use of gridded and basin averaged GRACE observations in assimilation. Finally, the evaluations presented in the paper indicate that GRACE DA can be helpful in improving the representation of droughts.

  4. Variable thickness transient ground-water flow model. Volume 3. Program listings

    International Nuclear Information System (INIS)

    Reisenauer, A.E.

    1979-12-01

    The Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program is developing and applying the methodology for assessing the far-field, long-term post-closure safety of deep geologic nuclear waste repositories. AEGIS is being performed by Pacific Northwest Laboratory (PNL) under contract with the Office of Nuclear Waste Isolation (OWNI) for the Department of Energy (DOE). One task within AEGIS is the development of methodology for analysis of the consequences (water pathway) from loss of repository containment as defined by various release scenarios. Analysis of the long-term, far-field consequences of release scenarios requires the application of numerical codes which simulate the hydrologic systems, model the transport of released radionuclides through the hydrologic systems to the biosphere, and, where applicable, assess the radiological dose to humans. Hydrologic and transport models are available at several levels of complexity or sophistication. Model selection and use are determined by the quantity and quality of input data. Model development under AEGIS and related programs provides three levels of hydrologic models, two levels of transport models, and one level of dose models (with several separate models). This is the third of 3 volumes of the description of the VTT (Variable Thickness Transient) Groundwater Hydrologic Model - second level (intermediate complexity) two-dimensional saturated groundwater flow

  5. Signal and noise in Gravity Recovery and Climate Experiment (GRACE) observed surface mass variations

    NARCIS (Netherlands)

    Schrama, E.J.O.; Wouters, B.; Lavallée, D.A.

    2007-01-01

    The Gravity Recovery and Climate Experiment (GRACE) product used for this study consists of 43 monthly potential coefficient sets released by the GRACE science team which are used to generate surface mass thickness grids expressed as equivalent water heights (EQWHs). We optimized both the smoothing

  6. Estimating continental water storage variations in Central Asia area using GRACE data

    International Nuclear Information System (INIS)

    Dapeng, Mu; Zhongchang, Sun; Jinyun, Guo

    2014-01-01

    The goal of GRACE satellite is to determine time-variations of the Earth's gravity, and particularly the effects of fluid mass redistributions at the surface of the Earth. This paper uses GRACE Level-2 RL05 data provided by CSR to estimate water storage variations of four river basins in Asia area for the period from 2003 to 2011. We apply a two-step filtering method to reduce the errors in GRACE data, which combines Gaussian averaging function and empirical de-correlation method. We use GLDAS hydrology to validate the result from GRACE. Special averaging approach is preformed to reduce the errors in GLDAS. The results of former three basins from GRACE are consistent with GLDAS hydrology model. In the Tarim River basin, there is more discrepancy between GRACE and GLDAS. Precipitation data from weather station proves that the results of GRACE are more plausible. We use spectral analysis to obtain the main periods of GRACE and GLDAS time series and then use least squares adjustment to determine the amplitude and phase. The results show that water storage in Central Asia is decreasing

  7. Evaluating Renewable Groundwater Stress with GRACE data in Greece

    Science.gov (United States)

    Lakshmi, V.; Gemitzi, A.

    2016-12-01

    Groundwater is a resilient water source and its importance as a fundamental resource is even greater in times of drought where groundwater stress conditions are greatest for areas like Mediterranean and adverse climate change effects are expected. The present study evaluates Renewable Groundwater Stress (RGS) as the ratio of groundwater use to groundwater availability, quantifying use as the trend in GRACE-derived subsurface anomalies (ΔGWtrend) and renewable groundwater availability as mean annual recharge. Estimates for mean annual recharge were used from groundwater studies conducted for the various regions in Greece, mainly in the form of numerical models. Our results highlighted two RGS regimes in Greece out of the four characteristic stress regimes, i.e. Overstressed, Variable Stress, Human-Dominated Stress and Unstressed, defined as a function of the sign of use and the sign of groundwater availability (positive or negative). Variable Stress areas are found in central Greece (Thessaly region), where intense agricultural activities take place, with negative ΔGWtrend values combined with positive mean annual recharge rates. RGS values range from -0.05 - 0, indicating however a low impact area. Within this region, adverse effects of groundwater overexploitation are already evident, based on the negative GRACE anomalies, recharge however still remains positive, amending the adverse over pumping impacts. The rest of Greek aquifers fall within the unstressed category, with RGS values from 0.02 - 0.05, indicating that the rate of use is less than the natural recharge rate. The highest Unstressed RGS values are observed in Crete Island and in Northeastern Greece. However, the case of Crete is highly uncertain, as precipitation and recharge in this area demonstrate exceptionally high variability and the coarse resolution of GRACE results does not allow for reliable estimates.

  8. Monitoring Lakes in Africa with Altimetry and GRACE

    Science.gov (United States)

    Carabajal, C. C.; Boy, J. P.

    2017-12-01

    Thanks to more than two decades of radar altimetry measurements from TOPEX/POSEIDON, Jason 1, 2 and 3, ENVISAT and others, 18 Ice, Cloud and Land Elevation Satellite (ICESat) laser altimeter measurement campaigns over 6 years, and 15 years of Gravity Recovery And Climate Experiment (GRACE) observations, water levels changes of major lakes and reservoirs can be remotely measured regularly with unprecedented precision, facilitating monitoring of continental water storage variations. Smaller footprint laser altimeters like ICESat are more suitable for the retrieval of water level variations of small inland water bodies, better discriminating water returns when water height measurements have the potential to be contaminated by land or vegetation. Using imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) contemporaneous with the altimetry data collections, in combination with careful examination of the laser waveforms, one can better isolate returns form the water surface. Combining these altimetry observations, we derive and compare water height estimates for several lakes and reservoirs in Africa from radar and laser altimetry measurements, we estimate the surface extent of each individual water body from available MODIS imagery, and derive corresponding estimates of volume variations for each water body. Mass variations from time-variable gravity measurements from the GRACE mission, using the latest one-degree global iterated mascons solution from GSFC are then transformed into volume changes, assuming a constant density, and compared to altimetry plus imagery estimates. These methods demonstrate the power of combined observations to monitor water resources and facilitate their management. Upcoming laser altimetry missions like ICESat-2, with vastly improved coverage and temporal sampling, continuous observations, better measurements techniques, including inland water products specifically formulated for these applications, when combined with SWOT

  9. Using GPS and GRACE data to assess Solid Earth elastic parameters at regional scale

    DEFF Research Database (Denmark)

    Barletta, Valentina Roberta; Borghi, A.; Aoudia, A.

    2012-01-01

    We propose a way to combine GPS and GRACE data for regional scale cross check and validation especially of the most commonly used PREM (Preliminary Earth Reference Model). In form of h and k Love numbers, global PREM is very often used to simulate elastic rebound due to present-day ice mass loss......, to derive the mass distribution produced by the observed GRACE time series, and it is also used for atmospheric loading correction both in GPS and in GRACE dealiasing products. GRACE data provide load estimates, usually given as water equivalent mass distribution, from which one derives the Earth elastic...... response, by convolution with suitable elastic green functions, relying on selected Earth model and related layering and elastic parameters. We calculate at regional scale the time series of monthly uplift associated with the mass redistribution observed by GRACE implementing the high resolution technique...

  10. Graceful, harmonious and magic type labelings relations and techniques

    CERN Document Server

    López, Susana C

    2017-01-01

    Aimed toward upper undergraduate and graduate students in mathematics, this book examines the foremost forms of graph labelings including magic, harmonious, and graceful labelings. An overview of basic graph theory concepts and notation is provided along with the origins of graph labeling. Common methods and techniques are presented introducing readers to links between graph labels. A variety of useful techniques are presented to analyze and understand properties of graph labelings. The classical results integrated with new techniques, complete proofs, numerous exercises, and a variety of open problems, will provide readers with a solid understanding of graph labelings.

  11. Checkpointing for graceful degradation in distributed embedded systems

    Science.gov (United States)

    Sababha, Belal Hussein

    Graceful degradation is an approach to developing dependable safety-critical embedded applications, where redundant active or standby resources are used to cope with faults through a system reconfiguration at run-time. Compared to traditional hardware and software redundancy, it is a promising technique that may achieve dependability with a significant reduction in cost, size, weight, and power requirements. Reconfiguration at run-time necessitates using proper checkpointing protocols to support state reservation to ensure correct task restarts after a system reconfiguration. One of the most common checkpointing protocols are communication induced checkpointing (CIC) protocols, which are well developed and understood for large parallel and information systems, but not much has been done for resource limited embedded systems. This work implements and evaluates some of the most common CIC protocols in a periodic resource constrained distributed embedded system for graceful degradation purposes. A test-bed has been developed and used for the evaluation of the various protocols. The implemented protocols are thoroughly studied and performances are contrasted. Specifically the periodicity property and how it benefits checkpointing in embedded systems is investigated. This work introduces a unique effort of CIC protocol implementation and evaluation in the field of distributed embedded systems. Other than providing a test-bed for graceful degradation support, this work shows that some checkpointing protocols that are not efficient in large information systems and supercomputers perform well in embedded systems. We show that a simple index-based CIC protocol, such as the BCS protocol, is more appropriate in embedded system applications compared to other protocols that piggyback a significant amount of information to reduce the number of forced checkpoints. Finally, this work proposes a whole graceful degradation approach to achieve fault tolerance in resource constrained

  12. Seasonal Gravity Field Variations from GRACE and Hydrological Models

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Hinderer, Jacques; Lemoine, Frank G.

    2004-01-01

    . Four global hydrological models covering the same period in 2002–2003 as the GRACE observations were investigated to for their mutual consistency in estimates of annual variation in terrestrial water storage and related temporal changes in gravity field. The hydrological models differ by a maximum of 2...... µGal or nearly 5 cm equivalent water storage in selected regions. Integrated over all land masses the standard deviation among the annual signal from the four hydrological models are 0.6 µGal equivalent to around 1.4 cm in equivalent water layer thickness. The estimated accuracy of the annual...

  13. Complete mitogenome of the Graceful Shark Carcharhinus amblyrhynchoides (Carcharhiniformes: Carcharhinidae).

    Science.gov (United States)

    Feutry, Pierre; Pillans, Richard D; Kyne, Peter M; Chen, Xiao

    2016-01-01

    In this manuscript we describe the first complete mitochondrial sequence for the Near Threatened Graceful Shark Carcharhinus amblyrhynchoides. It is 16,705 bp in length, consists of two rRNA genes, 22 tRNA genes, 13 protein-coding genes and one control region with the typical gene arrangement pattern and translate orientation in vertebrates. The overall base composition is 31.4% A, 25.1% C, 13.2% G and 30.3% T. The shortest tRNA-Ser2 cannot fold into a clover-leaf secondary structure due to the lack of the dihydrouridine arm.

  14. Solar maximum mission: Ground support programs at the Harvard Radio Astronomy Station

    Science.gov (United States)

    Maxwell, A.

    1983-01-01

    Observations of the spectral characteristics of solar radio bursts were made with new dynamic spectrum analyzers of high sensitivity and high reliability, over the frequency range 25-580 MHz. The observations also covered the maximum period of the current solar cycle and the period of international cooperative programs designated as the Solar Maximum Year. Radio data on shock waves generated by solar flares were combined with optical data on coronal transients, taken with equipment on the SMM and other satellites, and then incorporated into computer models for the outward passage of fast-mode MHD shocks through the solar corona. The MHD models are non-linear, time-dependent and for the most recent models, quasi-three-dimensional. They examine the global response of the corona for different types of input pulses (thermal, magnetic, etc.) and for different magnetic topologies (for example, open and closed fields). Data on coronal shocks and high-velocity material ejected from solar flares have been interpreted in terms of a model consisting of three main velocity regimes.

  15. Evapotranspiration Estimation over Yangtze River Basin from GRACE satellite measurement and in situ data

    Science.gov (United States)

    Li, Qiong; Luo, Zhicai; Zhong, Bo; Wang, Haihong; Zhou, Zebing

    2016-04-01

    As the critical component of hydrologic cycle, evapotranspiration (ET) plays an important role in global water exchanges and energy flow across the hydrosphere, atmosphere and biosphere. Influenced by the Asian monsoon, the Yangtze River Basin (YRB) suffer from the several severe floods and droughts over the last decades due to the significant difference between temporal and spatial distribution terrestrial water storages. As an indispensable part, it is practically important to assessment ET in the YRB accompany with increased population and rapid economic and agriculture development. Average ET over the YRB is computed as the residual of terrestrial water budget using the Gravity Recovery and Climate Experiment (GRACE) satellite-based measurements and the ground-based observations. The GRACE-based ET were well coincidence with the ET from MODIS, with the correlation coefficient of 0.853, and the correlation coefficient is 0.696 while comparing with the ET ground-based observation. The mean monthly average of ET from these various estimates is 56.9 mm/month over the whole YRB, and peak between June and August. Monthly variations of ET reach a maximum in Wujiang with 69.11 mm/month and a minimum in Jinshajiang with 39.01 mm/month. Based on the correlation between ET and independent estimates of near-surface temperature and soil moisture, it is showed that as the temperature increased, the ET of the seven sub-catchment were rising except for the Poyang Lake and Donting Lake. And we also can infer that the midstream of YRB is significant correlated with ESON especially in the Hanjiang basin. The Surface Humidity Index over the YRB was gradually decreased and its variations in each sub-catchment showed a significant decreasing trend in Jinshajiang and Mingjiang. This research has important potential for use in large-scale water budget assessments and intercomparison studies. Acknowledgements: This research is supported by the National Natural Science Foundation of

  16. On the origins of Earth rotation anomalies: New insights on the basis of both “paleogeodetic” data and Gravity Recovery and Climate Experiment (GRACE) data

    Science.gov (United States)

    Peltier, W. R.; Luthcke, Scott B.

    2009-11-01

    The theory previously developed to predict the impact on Earth's rotational state of the late Pleistocene glaciation cycle is extended. In particular, we examine the extent to which a departure of the infinite time asymptote of the viscoelastic tidal Love number of degree 2, "k2T," from the observed "fluid" Love number, "kf," impacts the theory. A number of tests of the influence of the difference in these Love numbers on theoretical predictions of the model of the glacial isostatic adjustment (GIA) process are explored. Relative sea level history predictions are shown not to be sensitive to the difference even though they are highly sensitive to the influence of the changing rotational state itself. We also explore in detail the accuracy with which the Gravity Recovery and Climate Experiment (GRACE) satellite system is able to observe the global GIA process including the time-dependent amplitude of the degree 2 and order 1 spherical harmonic components of the gravitational field, the only components that are significantly influenced by rotational effects. It is explicitly shown that the GRACE observation of these properties of the time-varying gravitational field is sufficiently accurate to rule out the values predicted by the ICE-5G (VM2) model of Peltier (2004). However, we also note that this model is constrained only by data from an epoch during which modern greenhouse gas induced melting of both the great polar ice-sheets and small ice sheets and glaciers was not occurring. Such modern loss of grounded continental ice strongly influences the evolving rotational state of the planet and thus the values of the degree 2 and order 1 Stokes coefficients as they are currently being measured by the GRACE satellite system. A series of sensitivity tests are employed to demonstrate this fact. We suggest that the accuracy of scenarios for modern land ice melting may be tested by ensuring that such scenarios conform to the GRACE observations of these crucial time

  17. GIA Model Statistics for GRACE Hydrology, Cryosphere, and Ocean Science

    Science.gov (United States)

    Caron, L.; Ivins, E. R.; Larour, E.; Adhikari, S.; Nilsson, J.; Blewitt, G.

    2018-03-01

    We provide a new analysis of glacial isostatic adjustment (GIA) with the goal of assembling the model uncertainty statistics required for rigorously extracting trends in surface mass from the Gravity Recovery and Climate Experiment (GRACE) mission. Such statistics are essential for deciphering sea level, ocean mass, and hydrological changes because the latter signals can be relatively small (≤2 mm/yr water height equivalent) over very large regions, such as major ocean basins and watersheds. With abundant new >7 year continuous measurements of vertical land motion (VLM) reported by Global Positioning System stations on bedrock and new relative sea level records, our new statistical evaluation of GIA uncertainties incorporates Bayesian methodologies. A unique aspect of the method is that both the ice history and 1-D Earth structure vary through a total of 128,000 forward models. We find that best fit models poorly capture the statistical inferences needed to correctly invert for lower mantle viscosity and that GIA uncertainty exceeds the uncertainty ascribed to trends from 14 years of GRACE data in polar regions.

  18. Climate-driven seasonal geocenter motion during the GRACE period

    Science.gov (United States)

    Zhang, Hongyue; Sun, Yu

    2018-03-01

    Annual cycles in the geocenter motion time series are primarily driven by mass changes in the Earth's hydrologic system, which includes land hydrology, atmosphere, and oceans. Seasonal variations of the geocenter motion have been reliably determined according to Sun et al. (J Geophys Res Solid Earth 121(11):8352-8370, 2016) by combining the Gravity Recovery And Climate Experiment (GRACE) data with an ocean model output. In this study, we reconstructed the observed seasonal geocenter motion with geophysical model predictions of mass variations in the polar ice sheets, continental glaciers, terrestrial water storage (TWS), and atmosphere and dynamic ocean (AO). The reconstructed geocenter motion time series is shown to be in close agreement with the solution based on GRACE data supporting with an ocean bottom pressure model. Over 85% of the observed geocenter motion time series, variance can be explained by the reconstructed solution, which allows a further investigation of the driving mechanisms. We then demonstrated that AO component accounts for 54, 62, and 25% of the observed geocenter motion variances in the X, Y, and Z directions, respectively. The TWS component alone explains 42, 32, and 39% of the observed variances. The net mass changes over oceans together with self-attraction and loading effects also contribute significantly (about 30%) to the seasonal geocenter motion in the X and Z directions. Other contributing sources, on the other hand, have marginal (less than 10%) impact on the seasonal variations but introduce a linear trend in the time series.

  19. Characteristic precipitation patterns of El Niño/La Niña in time-variable gravity fields by GRACE

    OpenAIRE

    Morishita, Yu; Heki, Kosuke

    2008-01-01

    El Niño and La Niña are known to bring about characteristic patterns of anomalous precipitation in various regions of the world. We extracted temporary and regional gravity changes from monthly gravity fields recovered by the GRACE satellites, and converted them to the changes in surface mass, possibly ground or subsurface water in land area. Such mass changes in the 2006-2007 El Niño and 2005-2006 La Niña episodes agreed well with precipitation anomaly patterns inferred from meteorological r...

  20. High-frequency signal and noise estimates of CSR GRACE RL04

    Science.gov (United States)

    Bonin, Jennifer A.; Bettadpur, Srinivas; Tapley, Byron D.

    2012-12-01

    A sliding window technique is used to create daily-sampled Gravity Recovery and Climate Experiment (GRACE) solutions with the same background processing as the official CSR RL04 monthly series. By estimating over shorter time spans, more frequent solutions are made using uncorrelated data, allowing for higher frequency resolution in addition to daily sampling. Using these data sets, high-frequency GRACE errors are computed using two different techniques: assuming the GRACE high-frequency signal in a quiet area of the ocean is the true error, and computing the variance of differences between multiple high-frequency GRACE series from different centers. While the signal-to-noise ratios prove to be sufficiently high for confidence at annual and lower frequencies, at frequencies above 3 cycles/year the signal-to-noise ratios in the large hydrological basins looked at here are near 1.0. Comparisons with the GLDAS hydrological model and high frequency GRACE series developed at other centers confirm CSR GRACE RL04's poor ability to accurately and reliably measure hydrological signal above 3-9 cycles/year, due to the low power of the large-scale hydrological signal typical at those frequencies compared to the GRACE errors.

  1. GRACE-Assimilated Drought Indicators for the U.S. Drought Monitor

    Science.gov (United States)

    Rui, Hualan; Vollmer, Bruce; Teng, Bill; Loeser, Carlee; Beaudoing, Hiroko; Rodell, Matt

    2018-01-01

    The Gravity Recovery and Climate Experiment (GRACE) mission detects changes in Earth's gravity field by precisely monitoring the changes in distance between two satellites orbiting the Earth in tandem. Scientists at NASA's Goddard Space Flight Center generate GRACE-assimilated groundwater and soil moisture drought indicators each week, for drought monitor-related studies and applications. The GRACE-assimilated Drought Indicator Version 2.0 data product (GRACE-DA-DM V2.0) is archived at, and distributed by, the NASA GES DISC (Goddard Earth Sciences Data and Information Services Center). More information about the data and data access is available on the data product landing page at https://disc.gsfc.nasa.gov/datasets /GRACEDADM_CLSM0125US_7D_2.0/summary. The GRACE-DA-DM V2.0 data product contains three drought indicators: Groundwater Percentile, Root Zone Soil Moisture Percentile, and Surface Soil Moisture Percentile. The drought indicators are of wet or dry conditions, expressed as a percentile, indicating the probability of occurrence within the period of record from 1948 to 2012. These GRACE-assimilated drought indicators, with improved spatial and temporal resolutions, should provide a more comprehensive and objective identification of drought conditions. This presentation describes the basic characteristics of the data and data services at NASA GES DISC and collaborative organizations, and uses a few examples to demonstrate the simple ways to explore the GRACE-assimilated drought indicator data.

  2. ITSG-Grace2016 data preprocessing methodologies revisited: impact of using Level-1A data products

    Science.gov (United States)

    Klinger, Beate; Mayer-Gürr, Torsten

    2017-04-01

    For the ITSG-Grace2016 release, the gravity field recovery is based on the use of official GRACE (Gravity Recovery and Climate Experiment) Level-1B data products, generated by the Jet Propulsion Laboratory (JPL). Before gravity field recovery, the Level-1B instrument data are preprocessed. This data preprocessing step includes the combination of Level-1B star camera (SCA1B) and angular acceleration (ACC1B) data for an improved attitude determination (sensor fusion), instrument data screening and ACC1B data calibration. Based on a Level-1A test dataset, provided for individual month throughout the GRACE period by the Center of Space Research at the University of Texas at Austin (UTCSR), the impact of using Level-1A instead of Level-1B data products within the ITSG-Grace2016 processing chain is analyzed. We discuss (1) the attitude determination through an optimal combination of SCA1A and ACC1A data using our sensor fusion approach, (2) the impact of the new attitude product on temporal gravity field solutions, and (3) possible benefits of using Level-1A data for instrument data screening and calibration. As the GRACE mission is currently reaching its end-of-life, the presented work aims not only at a better understanding of GRACE science data to reduce the impact of possible error sources on the gravity field recovery, but it also aims at preparing Level-1A data handling capabilities for the GRACE Follow-On mission.

  3. Sensitivity of GRACE-derived estimates of groundwater-level changes in southern Ontario, Canada

    Science.gov (United States)

    Hachborn, Ellen; Berg, Aaron; Levison, Jana; Ambadan, Jaison Thomas

    2017-12-01

    Amidst changing climates, understanding the world's water resources is of increasing importance. In Ontario, Canada, low water conditions are currently assessed using only precipitation and watershed-based stream gauges by the Conservation Authorities in Ontario and the Ministry of Natural Resources and Forestry. Regional groundwater-storage changes in Ontario are not currently measured using satellite data by research institutes. In this study, contributions from the Gravity Recovery and Climate Experiment (GRACE) data are compared to a hydrogeological database covering southern Ontario from 2003 to 2013, to determine the suitability of GRACE total water storage estimates for monitoring groundwater storage in this location. Terrestrial water storage data from GRACE were used to determine monthly groundwater storage (GWS) anomaly values. GWS values were also determined by multiplying groundwater-level elevations (from the Provincial Groundwater Monitoring Network wells) by specific yield. Comparisons of GRACE-derived GWS to well-based GWS data determined that GRACE is sufficiently sensitive to obtain a meaningful signal in southern Ontario. Results show that GWS values produced by GRACE are useful for identifying regional changes in groundwater storage in areas with limited available hydrogeological characterization data. Results also indicate that GRACE may have an ability to forecast changes in groundwater storage, which will become useful when monitoring climate shifts in the near future.

  4. User's guide to Model Viewer, a program for three-dimensional visualization of ground-water model results

    Science.gov (United States)

    Hsieh, Paul A.; Winston, Richard B.

    2002-01-01

    Model Viewer is a computer program that displays the results of three-dimensional groundwater models. Scalar data (such as hydraulic head or solute concentration) may be displayed as a solid or a set of isosurfaces, using a red-to-blue color spectrum to represent a range of scalar values. Vector data (such as velocity or specific discharge) are represented by lines oriented to the vector direction and scaled to the vector magnitude. Model Viewer can also display pathlines, cells or nodes that represent model features such as streams and wells, and auxiliary graphic objects such as grid lines and coordinate axes. Users may crop the model grid in different orientations to examine the interior structure of the data. For transient simulations, Model Viewer can animate the time evolution of the simulated quantities. The current version (1.0) of Model Viewer runs on Microsoft Windows 95, 98, NT and 2000 operating systems, and supports the following models: MODFLOW-2000, MODFLOW-2000 with the Ground-Water Transport Process, MODFLOW-96, MOC3D (Version 3.5), MODPATH, MT3DMS, and SUTRA (Version 2D3D.1). Model Viewer is designed to directly read input and output files from these models, thus minimizing the need for additional postprocessing. This report provides an overview of Model Viewer. Complete instructions on how to use the software are provided in the on-line help pages.

  5. Status of Electrostatic Accelerometer Development for Gravity Recovery and Climate Experiment Follow-On Mission (GRACE FO)

    Science.gov (United States)

    Perrot, Eddy; Boulanger, Damien; Christophe, Bruno; Foulon, Bernard; Liorzou, Françoise; Lebat, Vincent; Huynh, Phuong-Anh

    2015-04-01

    The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory), is an Earth-orbiting gravity mission, continuation of the GRACE mission, which will produce an accurate model of the Earth's gravity field variation providing global climatic data during five years at least. The mission involves two satellites in a loosely controlled tandem formation, with a micro-wave link measuring the inter-satellites distance variation. Earth's mass distribution non-uniformities cause variations of the inter-satellite distance. This variation is measured to recover gravity, after subtracting the non-gravitational contributors, as the residual drag. ONERA (the French Aerospace Lab) is developing, manufacturing and testing electrostatic accelerometers measuring this residual drag applied on the satellites. The accelerometer is composed of two main parts: the Sensor Unit (including the Sensor Unit Mechanics - SUM - and the Front-End Electronic Unit - FEEU) and the Interface Control Unit - ICU. In the Accelerometer Core, located in the Sensor Unit Mechanics, the proof mass is levitated and maintained at the center of an electrode cage by electrostatic forces. Thus, any drag acceleration applied on the satellite involves a variation on the servo-controlled electrostatic suspension of the mass. The voltage on the electrodes providing this electrostatic force is the measurement output of the accelerometer. The impact of the accelerometer defaults (geometry, electronic and parasitic forces) leads to bias, misalignment and scale factor error, non-linearity and noise. Some of these accelerometer defaults are characterized by tests with micro-gravity pendulum bench on ground and with drops in ZARM catapult. The Critical Design Review was achieved successfully on September 2014. The Engineering Model (EM) was integrated and tested successfully, with ground levitation, drops, Electromagnetic Compatibility and thermal vacuum. The integration of the first Flight Model has begun on December 2014

  6. Tests Results of the Electrostatic Accelerometer Flight Models for Gravity Recovery and Climate Experiment Follow-On Mission (GRACE FO)

    Science.gov (United States)

    Perrot, E.; Boulanger, D.; Christophe, B.; Foulon, B.; Lebat, V.; Huynh, P. A.; Liorzou, F.

    2015-12-01

    The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory), is an Earth-orbiting gravity mission, continuation of the GRACE mission, which will produce an accurate model of the Earth's gravity field variation providing global climatic data during five years at least. The mission involves two satellites in a loosely controlled tandem formation, with a micro-wave link measuring the inter-satellites distance variation. Earth's mass distribution non-uniformities cause variations of the inter-satellite distance. This variation is measured to recover gravity, after subtracting the non-gravitational contributors, as the residual drag. ONERA (the French Aerospace Lab) is developing, manufacturing and testing electrostatic accelerometers measuring this residual drag applied on the satellites. The accelerometer is composed of two main parts: the Sensor Unit (including the Sensor Unit Mechanics - SUM - and the Front-End Electronic Unit - FEEU) and the Interface Control Unit - ICU. In the Accelerometer Core, located in the Sensor Unit Mechanics, the proof mass is levitated and maintained at the center of an electrode cage by electrostatic forces. Thus, any drag acceleration applied on the satellite involves a variation on the servo-controlled electrostatic suspension of the mass. The voltage on the electrodes providing this electrostatic force is the output measurement of the accelerometer. The impact of the accelerometer defaults (geometry, electronic and parasitic forces) leads to bias, misalignment and scale factor error, non-linearity and noise. Some of these accelerometer defaults are characterized by tests with micro-gravity pendulum bench on ground and with drops in ZARM catapult. The Critical Design Review was achieved successfully on September 2014. The Engineering Model (EM) was integrated and tested successfully, with ground levitation, drops, Electromagnetic Compatibility and thermal vacuum. The integration of the two Flight Models was done on July 2015. The

  7. Automatic computation of cross sections in HEP. Status of GRACE system

    International Nuclear Information System (INIS)

    Yuasa, F.; Fujimoto, J.; Ishikawa, T.

    2000-01-01

    For the study of reactions in High Energy Physics (HEP) automatic computation systems have been developed are widely used nowadays. GRACE is one of such systems and it has achieved much success in analyzing experimental data. Since we deal with the cross section whose value can be given by calculating hundreds of Feynman diagrams, we manage the large scale calculation, so that effective symbolic manipulation, the treat of singularity in the numerical integration are required. The talk will describe the software design of GRACE system and computational techniques in the GRACE. (author)

  8. Using Tikhonov Regularization for Spatial Projections from CSR Regularized Spherical Harmonic GRACE Solutions

    Science.gov (United States)

    Save, H.; Bettadpur, S. V.

    2013-12-01

    It has been demonstrated before that using Tikhonov regularization produces spherical harmonic solutions from GRACE that have very little residual stripes while capturing all the signal observed by GRACE within the noise level. This paper demonstrates a two-step process and uses Tikhonov regularization to remove the residual stripes in the CSR regularized spherical harmonic coefficients when computing the spatial projections. We discuss methods to produce mass anomaly grids that have no stripe features while satisfying the necessary condition of capturing all observed signal within the GRACE noise level.

  9. Inflation with a graceful exit in a random landscape

    International Nuclear Information System (INIS)

    Pedro, F.G.; Westphal, A.

    2016-11-01

    We develop a stochastic description of small-field inflationary histories with a graceful exit in a random potential whose Hessian is a Gaussian random matrix as a model of the unstructured part of the string landscape. The dynamical evolution in such a random potential from a small-field inflation region towards a viable late-time de Sitter (dS) minimum maps to the dynamics of Dyson Brownian motion describing the relaxation of non-equilibrium eigenvalue spectra in random matrix theory. We analytically compute the relaxation probability in a saddle point approximation of the partition function of the eigenvalue distribution of the Wigner ensemble describing the mass matrices of the critical points. When applied to small-field inflation in the landscape, this leads to an exponentially strong bias against small-field ranges and an upper bound N<<10 on the number of light fields N participating during inflation from the non-observation of negative spatial curvature.

  10. Inflation with a graceful exit in a random landscape

    Energy Technology Data Exchange (ETDEWEB)

    Pedro, F.G. [Univ. Autonoma de Madrid (Spain). Dept. de Fisica Teorica y Inst. de Fisica Teorica UAM/CSIC; Westphal, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group

    2016-11-15

    We develop a stochastic description of small-field inflationary histories with a graceful exit in a random potential whose Hessian is a Gaussian random matrix as a model of the unstructured part of the string landscape. The dynamical evolution in such a random potential from a small-field inflation region towards a viable late-time de Sitter (dS) minimum maps to the dynamics of Dyson Brownian motion describing the relaxation of non-equilibrium eigenvalue spectra in random matrix theory. We analytically compute the relaxation probability in a saddle point approximation of the partition function of the eigenvalue distribution of the Wigner ensemble describing the mass matrices of the critical points. When applied to small-field inflation in the landscape, this leads to an exponentially strong bias against small-field ranges and an upper bound N<<10 on the number of light fields N participating during inflation from the non-observation of negative spatial curvature.

  11. Gravity Variation in Siberia: GRACE Observation and Possible Causes

    Directory of Open Access Journals (Sweden)

    Benjamin Fong Chao

    2011-01-01

    Full Text Available We report the finding, from the GRACE observation, of an increasing trend in the gravity anomaly in Siberia at the rate of up to 0.5 ugal yr-1 during 2003/1 - 2009/12, in the backdrop of a negative anomaly of magnitude on the order of ~-10 mgal. In consideration of the non-uniqueness of the gravitational inverse problem, we examine in some detail the various possible geophysical causes to explain the increasing gravity signal. We find two geophysical mechanisms being the most plausible, namely the melting of permafrost and the GIA post-glacial rebound. We conclude that these two mechanisms cannot be ruled out as causes for the regional gravity increase in Siberia, based on gravity data and in want of ancillary geophysical data in the region. More definitive identification of the contributions of the various causes awaits further studies.

  12. Status and Assessments of CSR GRACE Level-2 Data Products

    Science.gov (United States)

    Bettadpur, Srinivas; Kang, Zhigui; Nagel, Peter; Pastor, Rick; Poole, Steve; Ries, John; Save, Himanshu

    2015-04-01

    The joint NASA/DLR GRACE mission has successfully operated for more than 13 years, and has provided a remarkable record of global mass flux due to a large variety of geophysical and climate processes at various spatio-temporal scales. The University of Texas Center for Space Research (CSR) hosts the mission PI, and is responsible for delivery of operational (presently denoted as Release-05 or RL05) gravity field data products. In addition, CSR generates and distributes a variety of other gravity field data products, including products generated from the use of satellite laser ranging data. This poster will provide an overview of all these data products, their relative quality, potential applications, and future plans for their development and delivery.

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

    Science.gov (United States)

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

    2015-10-01

    Representatives from countries and regions world-wide who have implemented modern competency-based radiation- or clinical oncology curricula for training medical specialists, met to determine the feasibility and value of an ongoing international collaboration. In this forum, educational leaders from the ESTRO School, encompassing many European countries adopting the ESTRO Core Curriculum, and clinician educators from Canada, Denmark, the United Kingdom, Australia and New Zealand considered the training and educational arrangements within their jurisdictions, identifying similarities and challenges between programs. Common areas of educational interest and need were defined, which included development of new competency statements and assessment tools, and the application of the latter. The group concluded that such an international cooperation, which might expand to include others with similar goals, would provide a valuable vehicle to ensure training program currency, through sharing of resources and expertise, and enhance high quality radiation oncology education. Potential projects for the Global Radiation Oncology Collaboration in Education (GRaCE) were agreed upon, as was a strategy designed to maintain momentum. This paper describes the rationale for establishing this collaboration, presents a comparative view of training in the jurisdictions represented, and reports early goals and priorities. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. RCRA Facility Investigation/Remedial Investigation Report for the Grace Road Site (631-22G)

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, E.

    1998-10-02

    This report summarizes the activities and documents the results of a Resource Conservation and Recovery Act Facility Investigation/Remedial Investigation conducted at Grace Road Site on the Savannah River Site near Aiken, South Carolina.

  15. RCRA Facility Investigation/Remedial Investigation Report for the Grace Road Site (631-22G)

    International Nuclear Information System (INIS)

    Palmer, E.

    1998-01-01

    This report summarizes the activities and documents the results of a Resource Conservation and Recovery Act Facility Investigation/Remedial Investigation conducted at Grace Road Site on the Savannah River Site near Aiken, South Carolina

  16. Assessing sequential data assimilation techniques for integrating GRACE data into a hydrological model

    KAUST Repository

    Khaki, M.; Hoteit, Ibrahim; Kuhn, M.; Awange, J.; Forootan, E.; van Dijk, A.; Schumacher, M.; Pattiaratchi, C.

    2017-01-01

    The time-variable terrestrial water storage (TWS) products from the Gravity Recovery And Climate Experiment (GRACE) have been increasingly used in recent years to improve the simulation of hydrological models by applying data assimilation techniques

  17. RFP to work on formation flying capabilities for spacecrafts for the GRACE project

    DEFF Research Database (Denmark)

    Riis, Troels; Thuesen, Gøsta; Kilsgaard, Søren

    1999-01-01

    The National Aeronautics and Space Agency of USA, NASA, are working on formation flying capabilities for spacecrafts, GRACE Project. IAU and JPL are developing the inter spacecraft attitude link to be used on the two spacecrafts.......The National Aeronautics and Space Agency of USA, NASA, are working on formation flying capabilities for spacecrafts, GRACE Project. IAU and JPL are developing the inter spacecraft attitude link to be used on the two spacecrafts....

  18. Measuring the Value of Earth Observation Information with the Gravity Research and Climate Experiment (GRACE) Satellite

    Science.gov (United States)

    Bernknopf, R.; Kuwayama, Y.; Brookshire, D.; Macauley, M.; Zaitchik, B.; Pesko, S.; Vail, P.

    2014-12-01

    Determining how much to invest in earth observation technology depends in part on the value of information (VOI) that can be derived from the observations. We design a framework and then evaluate the value-in-use of the NASA Gravity Research and Climate Experiment (GRACE) for regional water use and reliability in the presence of drought. As a technology that allows measurement of water storage, the GRACE Data Assimilation System (DAS) provides information that is qualitatively different from that generated by other water data sources. It provides a global, reproducible grid of changes in surface and subsurface water resources on a frequent and regular basis. Major damages from recent events such as the 2012 Midwest drought and the ongoing drought in California motivate the need to understand the VOI from remotely sensed data such as that derived from GRACE DAS. Our conceptual framework models a dynamic risk management problem in agriculture. We base the framework on information from stakeholders and subject experts. The economic case for GRACE DAS involves providing better water availability information. In the model, individuals have a "willingness to pay" (wtp) for GRACE DAS - essentially, wtp is an expression of savings in reduced agricultural input costs and for costs that are influenced by regional policy decisions. Our hypothesis is that improvements in decision making can be achieved with GRACE DAS measurements of water storage relative to data collected from groundwater monitoring wells and soil moisture monitors that would be relied on in the absence of GRACE DAS. The VOI is estimated as a comparison of outcomes. The California wine grape industry has features that allow it to be a good case study and a basis for extrapolation to other economic sectors. We model water use in this sector as a sequential decision highlighting the attributes of GRACE DAS input as information for within-season production decisions as well as for longer-term water reliability.

  19. Time-variations of the regional evapotranspiration rate from GRACE satellite gravimetry

    OpenAIRE

    Ramillien , Guillaume; Frappart , Frédéric; Güntner , Andreas; Ngo-Duc , Thanh; Cazenave , Anny; Laval , Katia

    2006-01-01

    International audience; Since its launch in March 2002, the GRACE mission is measuring the global time variations of the Earth's gravity field with a current resolution of ~500 km. Especially over the continents, these measurements represent the integrated land water mass including surface waters (lakes, wetlands and rivers), soil moisture, groundwater and snow cover. In this study, we use the GRACE land water solutions computed by Ramillien et al. (2005a) through an iterative inversion of mo...

  20. Water balance of the Arctic drainage system using GRACE gravimetry products

    OpenAIRE

    Frappart, F; Ramillien, G; Famiglietti, JS

    2011-01-01

    International audience; Land water and snow mass anomalies versus time were computed from the inversion of 50 GRACE geoids (August 2002 to February 2007) from the RL04 GFZ release and used to characterize the hydrology of the Arctic drainage system. GRACE-based time series have been compared to snow water equivalent and snow depth climatologies, and snowfall for validation purpose. Time series of regional averages of water volume were estimated for the 11 largest Peri-Arctic basins. Strong co...

  1. On Graceful Spider Graphs with at Most Four Legs of Lengths Greater than One

    Directory of Open Access Journals (Sweden)

    A. Panpa

    2016-01-01

    Full Text Available A graceful labeling of a tree T with n edges is a bijection f:V(T→{0,1,2,…,n} such that {|f(u-f(v|:uv∈E(T} equal to {1,2,…,n}. A spider graph is a tree with at most one vertex of degree greater than 2. We show that all spider graphs with at most four legs of lengths greater than one admit graceful labeling.

  2. Towards Designing Graceful Degradation into Trajectory Based Operations: A Human-systems Integration Approach

    Science.gov (United States)

    Edwards, Tamsyn; Lee, Paul

    2017-01-01

    One of the most fundamental changes to the air traffic management system in NextGen is the concept of trajectory based operations (TBO). With the introduction of such change, system safety and resilience is a critical concern, in particular, the ability of systems to gracefully degrade. In order to design graceful degradation into a TBO envrionment, knowledge of the potential causes of degradation, and appropriate solutions, is required. In addition, previous research has predominantly explored the technological contribution to graceful degradation, frequently neglecting to consider the role of the human operator, specifically, air traffic controllers (ATCOs). This is out of step with real-world operations, and potentially limits an ecologically valid understanding of achieving graceful degradation in an air traffic control (ATC) environment. The following literature review aims to identify and summarize the literature to date on the potential causes of degradation in ATC and the solutions that may be applied within a TBO context, with a specific focus on the contribution of the air traffic controller. A framework of graceful degradation, developed from the literature, is presented. It is argued that in order to achieve graceful degradation within TBO, a human-system integration approach must be applied.

  3. Towards Designing Graceful Degradation into Trajectory Based Operations: A Human-Machine System Integration Approach

    Science.gov (United States)

    Edwards, Tamsyn; Lee, Paul

    2017-01-01

    One of the most fundamental changes to the air traffic management system in NextGen is the concept of trajectory based operations (TBO). With the introduction of such change, system safety and resilience is a critical concern, in particular, the ability of systems to gracefully degrade. In order to design graceful degradation into a TBO envrionment, knowledge of the potential causes of degradation, and appropriate solutions, is required. In addition, previous research has predominantly explored the technological contribution to graceful degradation, frequently neglecting to consider the role of the human operator, specifically, air traffic controllers (ATCOs). This is out of step with real-world operations, and potentially limits an ecologically valid understanding of achieving graceful degradation in an air traffic control (ATC) environment. The following literature review aims to identify and summarize the literature to date on the potential causes of degradation in ATC and the solutions that may be applied within a TBO context, with a specific focus on the contribution of the air traffic controller. A framework of graceful degradation, developed from the literature, is presented. It is argued that in order to achieve graceful degradation within TBO, a human-system integration approach must be applied.

  4. Regional GRACE-based estimates of water mass variations over Australia: validation and interpretation

    Science.gov (United States)

    Seoane, L.; Ramillien, G.; Frappart, F.; Leblanc, M.

    2013-04-01

    Time series of regional 2°-by-2° GRACE solutions have been computed from 2003 to 2011 with a 10 day resolution by using an energy integral method over Australia [112° E 156° E; 44° S 10° S]. This approach uses the dynamical orbit analysis of GRACE Level 1 measurements, and specially accurate along-track K Band Range Rate (KBRR) residuals (1 μm s-1 level of error) to estimate the total water mass over continental regions. The advantages of regional solutions are a significant reduction of GRACE aliasing errors (i.e. north-south stripes) providing a more accurate estimation of water mass balance for hydrological applications. In this paper, the validation of these regional solutions over Australia is presented as well as their ability to describe water mass change as a reponse of climate forcings such as El Niño. Principal component analysis of GRACE-derived total water storage maps show spatial and temporal patterns that are consistent with independent datasets (e.g. rainfall, climate index and in-situ observations). Regional TWS show higher spatial correlations with in-situ water table measurements over Murray-Darling drainage basin (80-90%), and they offer a better localization of hydrological structures than classical GRACE global solutions (i.e. Level 2 GRGS products and 400 km ICA solutions as a linear combination of GFZ, CSR and JPL GRACE solutions).

  5. HYDROGRAV - Hydrological model calibration and terrestrial water storage monitoring from GRACE gravimetry and satellite altimetry, First results

    DEFF Research Database (Denmark)

    Andersen, O.B.; Krogh, P.E.; Michailovsky, C.

    2008-01-01

    Space-borne and ground-based time-lapse gravity observations provide new data for water balance monitoring and hydrological model calibration in the future. The HYDROGRAV project (www.hydrograv.dk) will explore the utility of time-lapse gravity surveys for hydrological model calibration and terre...... change from 2002 to 2008 along with in-situ gravity time-lapse observations and radar altimetry monitoring of surface water for the southern Africa river basins will be presented.......Space-borne and ground-based time-lapse gravity observations provide new data for water balance monitoring and hydrological model calibration in the future. The HYDROGRAV project (www.hydrograv.dk) will explore the utility of time-lapse gravity surveys for hydrological model calibration...... and terrestrial water storage monitoring. Merging remote sensing data from GRACE with other remote sensing data like satellite altimetry and also ground based observations are important to hydrological model calibration and water balance monitoring of large regions and can serve as either supplement or as vital...

  6. Impact of GPS antenna phase center and code residual variation maps on orbit and baseline determination of GRACE

    Science.gov (United States)

    Mao, X.; Visser, P. N. A. M.; van den IJssel, J.

    2017-06-01

    Precision Orbit Determination (POD) is a prerequisite for the success of many Low Earth Orbiting (LEO) satellite missions. With high-quality, dual-frequency Global Positioning System (GPS) receivers, typically precisions of the order of a few cm are possible for single-satellite POD, and of a few mm for relative POD of formation flying spacecraft with baselines up to hundreds of km. To achieve the best precision, the use of Phase Center Variation (PCV) maps is indispensable. For LEO GPS receivers, often a-priori PCV maps are obtained by a pre-launch ground campaign, which is not able to represent the real space-borne environment of satellites. Therefore, in-flight calibration of the GPS antenna is more widely conducted. This paper shows that a further improvement is possible by including the so-called Code Residual Variation (CRV) maps in absolute/undifferenced and relative/Double-differenced (DD) POD schemes. Orbit solutions are produced for the GRACE satellite formation for a four months test period (August-November, 2014), demonstrating enhanced orbit precision after first using the in-flight PCV maps and a further improvement after including the CRV maps. The application of antenna maps leads to a better consistency with independent Satellite Laser Ranging (SLR) and K-band Ranging (KBR) low-low Satellite-to-Satellite Tracking (ll-SST) observations. The inclusion of the CRV maps results also in a much better consistency between reduced-dynamic and kinematic orbit solutions for especially the cross-track direction. The improvements are largest for GRACE-B, where a cross-talk between the GPS main antenna and the occultation antenna yields higher systematic observation residuals. For high-precision relative POD which necessitates DD carrier-phase ambiguity fixing, in principle frequency-dependent PCV maps would be required. To this aim, use is made of an Extended Kalman Filter (EKF) that is capable of optimizing relative spacecraft dynamics and iteratively fixing

  7. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 3: Design philosophy and programming details

    Science.gov (United States)

    Torak, L.J.

    1993-01-01

    A MODular Finite-Element, digital-computer program (MODFE) was developed to simulate steady or unsteady-state, two-dimensional or axisymmetric ground-water-flow. The modular structure of MODFE places the computationally independent tasks that are performed routinely by digital-computer programs simulating ground-water flow into separate subroutines, which are executed from the main program by control statements. Each subroutine consists of complete sets of computations, or modules, which are identified by comment statements, and can be modified by the user without affecting unrelated computations elsewhere in the program. Simulation capabilities can be added or modified by either adding or modifying subroutines that perform specific computational tasks, and the modular-program structure allows the user to create versions of MODFE that contain only the simulation capabilities that pertain to the ground-water problem of interest. MODFE is written in a Fortran programming language that makes it virtually device independent and compatible with desk-top personal computers and large mainframes. MODFE uses computer storage and execution time efficiently by taking advantage of symmetry and sparseness within the coefficient matrices of the finite-element equations. Parts of the matrix coefficients are computed and stored as single-subscripted variables, which are assembled into a complete coefficient just prior to solution. Computer storage is reused during simulation to decrease storage requirements. Descriptions of subroutines that execute the computational steps of the modular-program structure are given in tables that cross reference the subroutines with particular versions of MODFE. Programming details of linear and nonlinear hydrologic terms are provided. Structure diagrams for the main programs show the order in which subroutines are executed for each version and illustrate some of the linear and nonlinear versions of MODFE that are possible. Computational aspects of

  8. Results of the indoor radiological survey at the W.R. Grace Co., Curtis Bay site, Baltimore, Maryland

    International Nuclear Information System (INIS)

    Cottrell, W.D.; Foley, R.D.; Johnson, C.A.

    1989-07-01

    The W.R. Grace Company, Davison Chemical Division, conducted developmental research and extraction of thorium from monazite ore at its Curtis Bay facility in Baltimore, Maryland, during the 1950s under contract to the Atomic Energy Commission (AEC). Only one of the numerous buildings on the site was used for these operations. A 1979 aerial survey of the site for the Department of Energy (DOE) indicated that a comprehensive ground survey was required to determine whether or not any contamination remained from the AEC activities in that building. A radiological scoping survey performed later that year for DOE by a team from the Measurement Applications and Development Group of the Health and Safety Research Division, Oak Ridge National Laboratory (ORNL), disclosed surface contamination (alpha) levels in excess of DOE criteria on all five levels of the building. As a result of this finding, two additional surveys were performed in 1986 by ORNL at the request of DOE to evaluate any present or potential health risk. They are detailed in this report. The results of the 1986 surveys revealed several areas having elevated levels of radiation as a result of significant quantities of thorium on some building surfaces such as floors and ceiling beams. Most areas were small spots and in locations of low occupancy; thus, the possibility for significant exposure to workers was judged to be low. To confirm this evaluation, annual radiation exposure estimates for workers frequenting the few, larger contaminated areas on the site were derived using ORNL survey data and occupancy factors provided by the W.R. Grace Company. Estimates ranged from 27 to 41 mrem/yr or a maximum of 41% of the basic dose limit of 100 mrem/yr for members of the general public. 2 refs., 14 figs., 8 tabs

  9. Groundwater Depletion in the West Liaohe River Basin, China and Its Implications Revealed by GRACE and In Situ Measurements

    Directory of Open Access Journals (Sweden)

    Yulong Zhong

    2018-03-01

    Full Text Available The West Liaohe River Basin (WLRB is one of the most sensitive areas to climate change in China and an important grain production base in the Inner Mongolia Autonomous Region of China. Groundwater depletion in this region is becoming a critical issue. Here, we used the Gravity Recovery and Climate Experiment (GRACE satellite data and in situ well observations to estimate groundwater storage (GWS variations and discussed the driving factors of GWS changes in the WLRB. GRACE detects a GWS decline rate of −0.92 ± 0.49 km3/yr in the WLRB during 2005–2011, consistent with the estimate from in situ observations (−0.96 ± 0.19 km3/yr. This long-term GWS depletion is attributed to reduced precipitation and extensive groundwater overexploitation in the 2000s. Long-term groundwater level observations and reconstructed total water storage variations since 1980 show favorable agreement with precipitation anomalies at interannual timescales, both of which are significantly influenced by the El Niño-Southern Oscillation (ENSO. Generally, the WLRB receives more/less precipitation during the El Niño/La Niña periods. One of the strongest El Niño events on record in 1997–1998 and a subsequent strong La Niña drastically transform the climate of WLRB into a decade-long drought period, and accelerate the groundwater depletion in the WLRB after 1998. This study demonstrates the significance of integrating satellite observations, ground-based measurements, and climatological data for interpreting regional GWS changes from a long-term perspective.

  10. GRASP [GRound-Water Adjunct Sensitivity Program]: A computer code to perform post-SWENT [simulator for water, energy, and nuclide transport] adjoint sensitivity analysis of steady-state ground-water flow: Technical report

    International Nuclear Information System (INIS)

    Wilson, J.L.; RamaRao, B.S.; McNeish, J.A.

    1986-11-01

    GRASP (GRound-Water Adjunct Senstivity Program) computes measures of the behavior of a ground-water system and the system's performance for waste isolation, and estimates the sensitivities of these measures to system parameters. The computed measures are referred to as ''performance measures'' and include weighted squared deviations of computed and observed pressures or heads, local Darcy velocity components and magnitudes, boundary fluxes, and travel distance and time along travel paths. The sensitivities are computed by the adjoint method and are exact derivatives of the performance measures with respect to the parameters for the modeled system, taken about the assumed parameter values. GRASP presumes steady-state, saturated grondwater flow, and post-processes the results of a multidimensional (1-D, 2-D, 3-D) finite-difference flow code. This document describes the mathematical basis for the model, the algorithms and solution techniques used, and the computer code design. The implementation of GRASP is verified with simple one- and two-dimensional flow problems, for which analytical expressions of performance measures and sensitivities are derived. The linkage between GRASP and multidimensional finite-difference flow codes is described. This document also contains a detailed user's manual. The use of GRASP to evaluate nuclear waste disposal issues has been emphasized throughout the report. The performance measures and their sensitivities can be employed to assist in directing data collection programs, expedite model calibration, and objectively determine the sensitivity of projected system performance to parameters

  11. Global models underestimate large decadal declining and rising water storage trends relative to GRACE satellite data

    Science.gov (United States)

    Scanlon, Bridget R.; Zhang, Zizhan; Save, Himanshu; Sun, Alexander Y.; van Beek, Ludovicus P. H.; Wiese, David N.; Reedy, Robert C.; Longuevergne, Laurent; Döll, Petra; Bierkens, Marc F. P.

    2018-01-01

    Assessing reliability of global models is critical because of increasing reliance on these models to address past and projected future climate and human stresses on global water resources. Here, we evaluate model reliability based on a comprehensive comparison of decadal trends (2002–2014) in land water storage from seven global models (WGHM, PCR-GLOBWB, GLDAS NOAH, MOSAIC, VIC, CLM, and CLSM) to trends from three Gravity Recovery and Climate Experiment (GRACE) satellite solutions in 186 river basins (∼60% of global land area). Medians of modeled basin water storage trends greatly underestimate GRACE-derived large decreasing (≤−0.5 km3/y) and increasing (≥0.5 km3/y) trends. Decreasing trends from GRACE are mostly related to human use (irrigation) and climate variations, whereas increasing trends reflect climate variations. For example, in the Amazon, GRACE estimates a large increasing trend of ∼43 km3/y, whereas most models estimate decreasing trends (−71 to 11 km3/y). Land water storage trends, summed over all basins, are positive for GRACE (∼71–82 km3/y) but negative for models (−450 to −12 km3/y), contributing opposing trends to global mean sea level change. Impacts of climate forcing on decadal land water storage trends exceed those of modeled human intervention by about a factor of 2. The model-GRACE comparison highlights potential areas of future model development, particularly simulated water storage. The inability of models to capture large decadal water storage trends based on GRACE indicates that model projections of climate and human-induced water storage changes may be underestimated. PMID:29358394

  12. Ice loading model for Glacial Isostatic Adjustment in the Barents Sea constrained by GRACE gravity observations

    Science.gov (United States)

    Root, Bart; Tarasov, Lev; van der Wal, Wouter

    2014-05-01

    The global ice budget is still under discussion because the observed 120-130 m eustatic sea level equivalent since the Last Glacial Maximum (LGM) can not be explained by the current knowledge of land-ice melt after the LGM. One possible location for the missing ice is the Barents Sea Region, which was completely covered with ice during the LGM. This is deduced from relative sea level observations on Svalbard, Novaya Zemlya and the North coast of Scandinavia. However, there are no observations in the middle of the Barents Sea that capture the post-glacial uplift. With increased precision and longer time series of monthly gravity observations of the GRACE satellite mission it is possible to constrain Glacial Isostatic Adjustment in the center of the Barents Sea. This study investigates the extra constraint provided by GRACE data for modeling the past ice geometry in the Barents Sea. We use CSR release 5 data from February 2003 to July 2013. The GRACE data is corrected for the past 10 years of secular decline of glacier ice on Svalbard, Novaya Zemlya and Frans Joseph Land. With numerical GIA models for a radially symmetric Earth, we model the expected gravity changes and compare these with the GRACE observations after smoothing with a 250 km Gaussian filter. The comparisons show that for the viscosity profile VM5a, ICE-5G has too strong a gravity signal compared to GRACE. The regional calibrated ice sheet model (GLAC) of Tarasov appears to fit the amplitude of the GRACE signal. However, the GRACE data are very sensitive to the ice-melt correction, especially for Novaya Zemlya. Furthermore, the ice mass should be more concentrated to the middle of the Barents Sea. Alternative viscosity models confirm these conclusions.

  13. Empowering families by engaging and relating Murri way: a grounded theory study of the implementation of the Cape York Baby Basket program.

    Science.gov (United States)

    McCalman, Janya; Searles, Andrew; Bainbridge, Roxanne; Ham, Rachael; Mein, Jacki; Neville, Johanna; Campbell, Sandra; Tsey, Komla

    2015-05-21

    Evaluating program outcomes without considering how the program was implemented can cause misunderstandings and inefficiencies when initiating program improvements. In conjunction with a program evaluation, reported elsewhere, this paper theorises the process of implementing an Indigenous Australian maternal and child health program. The Baby Basket program was developed in 2009 for the remote Cape York region and aimed to improve the attendance and engagement of Indigenous women at antenatal and postnatal clinics through providing three baskets of maternal and baby goods and associated health education. Constructivist grounded theory methods were used to generate and analyse data from qualitative interviews and focus groups with Indigenous women who received the baskets, their extended family members, and healthcare workers who delivered them. Data was coded in NVivo with concepts iteratively compared until higher order constructs and their relationships could be modelled to explain the common purpose for participants, the process involved in achieving that purpose, key strategies, conditions and outcomes. Theoretical terms are italicised. Program implementation entailed empowering families through a process of engaging and relating Murri (Queensland Indigenous) way. Key influencing conditions of the social environment were the remoteness of communities, keeping up with demand, families' knowledge, skills and roles and organisational service approaches and capacities. Engaging and relating Murri way occurred through four strategies: connecting through practical support, creating a culturally safe practice, becoming informed and informing others, and linking at the clinic. These strategies resulted in women and families taking responsibility for health through making healthy choices, becoming empowered health consumers and advocating for community changes. The theoretical model was applied to improve and revise Baby Basket program implementation, including

  14. Inflation with a graceful exit in a random landscape

    Energy Technology Data Exchange (ETDEWEB)

    Pedro, F.G. [Departamento de Física Teórica and Instituto de Física Teórica UAM/CSIC,Universidad Autónoma de Madrid,Cantoblanco, 28049 Madrid (Spain); Westphal, A. [Deutsches Elektronen-Synchrotron DESY, Theory Group,D-22603 Hamburg (Germany)

    2017-03-30

    We develop a stochastic description of small-field inflationary histories with a graceful exit in a random potential whose Hessian is a Gaussian random matrix as a model of the unstructured part of the string landscape. The dynamical evolution in such a random potential from a small-field inflation region towards a viable late-time de Sitter (dS) minimum maps to the dynamics of Dyson Brownian motion describing the relaxation of non-equilibrium eigenvalue spectra in random matrix theory. We analytically compute the relaxation probability in a saddle point approximation of the partition function of the eigenvalue distribution of the Wigner ensemble describing the mass matrices of the critical points. When applied to small-field inflation in the landscape, this leads to an exponentially strong bias against small-field ranges and an upper bound N≪10 on the number of light fields N participating during inflation from the non-observation of negative spatial curvature.

  15. Monitoring the spatio-temporal changes of terrestrial water storage using GRACE data in the Tarim River basin between 2002 and 2015.

    Science.gov (United States)

    Yang, Peng; Xia, Jun; Zhan, Chesheng; Qiao, Yunfeng; Wang, Yueling

    2017-10-01

    With the threat of water shortages intensifying, the need to identify the terrestrial water storage (TWS) variation in the Tarim River Basin (TRB) becomes very significant for managing its water resource. Due to the lack of large-scale hydrological data, this study employed the Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) to monitor TWS variation in the TRB during the period of 2002-2015, cooperating with two statistical techniques, Principal Component Analysis (PCA) - Empirical Orthogonal Function (EOF) and Multiple Linear Regression (MLR). Results indicated that (1) the Tropical rainfall measuring mission (TRMM) data can be applied well in the TRB; (2) the EOF result showed that both the time series of TRMM precipitation and GRACE-derived TWS in the TRB between 2002 and 2015 were dominated by the annual signals, which were followed by the semiannual signals; (3) the linear trend for the spatially averaged GRACE-derived TWS changes exhibited an decrease of 1.6±1.1mm/a, and the EOF result indicated a significant decrease of 4.1±1.5mm/a in the north of TRB; (4) while the precipitation variations was the major driver for the TWS changes, the GLDAS-derived TWS (i.e., soil moisture) decrease and ground water decrease played the major role in the TWS decrease in the north of TRB for the significant correlation (P<0.05). The changes of TWS might be linked to excessive exploitation of water resources, increased population, and shrinking water supplies, which would impact on the water level of the lakes or reservoir. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Ground-Water Quality Data in the Monterey Bay and Salinas Valley Basins, California, 2005 - Results from the California GAMA Program

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2007-01-01

    Ground-water quality in the approximately 1,000-square-mile Monterey Bay and Salinas Valley study unit was investigated from July through October 2005 as part of the California Ground-Water Ambient Monitoring and Assessment (GAMA) program. The study was designed to provide a spatially unbiased assessment of raw ground-water quality, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 94 public-supply wells and 3 monitoring wells in Monterey, Santa Cruz, and San Luis Obispo Counties. Ninety-one of the public-supply wells sampled were selected to provide a spatially distributed, randomized monitoring network for statistical representation of the study area. Six wells were sampled to evaluate changes in water chemistry: three wells along a ground-water flow path were sampled to evaluate lateral changes, and three wells at discrete depths from land surface were sampled to evaluate changes in water chemistry with depth from land surface. The ground-water samples were analyzed for volatile organic compounds (VOCs), pesticides, pesticide degradates, nutrients, major and minor ions, trace elements, radioactivity, microbial indicators, and dissolved noble gases (the last in collaboration with Lawrence Livermore National Laboratory). Naturally occurring isotopes (tritium, carbon-14, helium-4, and the isotopic composition of oxygen and hydrogen) also were measured to help identify the source and age of the sampled ground water. In total, 270 constituents and water-quality indicators were investigated for this study. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, and (or) blended with other waters to maintain water quality. In addition, regulatory thresholds apply to treated water that is served to the consumer, not to raw ground water. In this study, only six constituents, alpha radioactivity, N

  17. Dynamics of the Antarctic Circumpolar Current as seen by GRACE (Invited)

    Science.gov (United States)

    Thomas, M.; Dobslaw, H.; Bergmann, I.

    2010-12-01

    The Antarctic Circumpolar Current, being the strongest and longest ocean current on Earth, connects the three great ocean basins and contributes substantially to the global re-distribution of water masses, with a significant impact on global climate. Observational coverage from in-situ measurements is sparse due to the harsh environmental conditions, and satellite altimetry does not capture the full extent of the current due to seasonal sea-ice coverage. Ocean bottom pressure variations as sensed with the satellite gravity mission GRACE provide a promising way to broaden our observational basis. Besides monthly mean gravity fields that provide ocean bottom pressure variations averaged over 30 days, several alternative GRACE products with higher temporal resolution have been developed during the most recent years. These include 10-day solutions from GRGS Toulouse, weekly solutions from the GFZ Potsdam as well as constrained daily solutions from the University of Bonn which have been obtained by means of a Kalman filtering approach. In this presentation, ocean bottom pressure derived from these alternative GRACE releases will be contrasted against both in-situ observations and output from a numerical ocean model, highlighting the additional information contained in these GRACE solutions with respect to the standard monthly fields. By means of statistical analyses of ocean bottom pressure variations and barotropic transports it will be demonstrated how these new GRACE releases are contributing to our understanding of this highly dynamic great ocean conveyor.

  18. The Value of Information from a GRACE-Enhanced Drought Severity Index

    Science.gov (United States)

    Kuwayama, Y.; Bernknopf, R.; Macauley, M.; Brookshire, D.; Zaitchik, B. F.; Rodell, M.

    2013-12-01

    Water storage anomalies derived from the Gravity Recovery and Climate Experiment Data Assimilation System (GRACE-DAS) have been used to enhance the information contained in drought indicators. The potential value of this information is to inform local and regional decisions to improve economic welfare in the face of drought. Based on a characterization of current drought evaluations, a modeling framework has been structured to analyze the contributed value of the Earth observations in the assessment of the onset and duration of droughts and their regional impacts. The analysis focuses on (1) characterizing how GRACE-DAS provides Earth observation information for a drought warning, (2) assessing how a GRACE-DAS-enhanced U.S. Drought Monitor would improve economic outcomes in a region, and (3) applying this enhancement process in a decision framework to illustrate the potential role of GRACE data products in a recent drought and response scenario for a value-of-information (VOI) analysis. The VOI analysis quantifies the relative contribution of enhanced understanding and communication of the societal benefits associated with GRACE Earth observation science. Our emphasis is to illustrate the role of an enhanced National Integrated Drought Information System outlook on three key societal outcomes: effects on particular economic sectors, changes in land management decisions, and reductions in damages to ecosystem services.

  19. New GRACE-Derived Storage Change Estimates Using Empirical Mode Extraction

    Science.gov (United States)

    Aierken, A.; Lee, H.; Yu, H.; Ate, P.; Hossain, F.; Basnayake, S. B.; Jayasinghe, S.; Saah, D. S.; Shum, C. K.

    2017-12-01

    Estimated mass change from GRACE spherical harmonic solutions have north/south stripes and east/west banded errors due to random noise and modeling errors. Low pass filters like decorrelation and Gaussian smoothing are typically applied to reduce noise and errors. However, these filters introduce leakage errors that need to be addressed. GRACE mascon estimates (JPL and CSR mascon solutions) do not need decorrelation or Gaussian smoothing and offer larger signal magnitudes compared to the GRACE spherical harmonics (SH) filtered results. However, a recent study [Chen et al., JGR, 2017] demonstrated that both JPL and CSR mascon solutions also have leakage errors. We developed a new postprocessing method based on empirical mode decomposition to estimate mass change from GRACE SH solutions without decorrelation and Gaussian smoothing, the two main sources of leakage errors. We found that, without any post processing, the noise and errors in spherical harmonic solutions introduced very clear high frequency components in the spatial domain. By removing these high frequency components and reserve the overall pattern of the signal, we obtained better mass estimates with minimum leakage errors. The new global mass change estimates captured all the signals observed by GRACE without the stripe errors. Results were compared with traditional methods over the Tonle Sap Basin in Cambodia, Northwestern India, Central Valley in California, and the Caspian Sea. Our results provide larger signal magnitudes which are in good agreement with the leakage corrected (forward modeled) SH results.

  20. Low-degree gravity change from GPS data of COSMIC and GRACE satellite missions

    Science.gov (United States)

    Lin, Tingjung; Hwang, Cheinway; Tseng, Tzu-Pang; Chao, B. F.

    2012-01-01

    This paper demonstrates estimation of time-varying gravity harmonic coefficients from GPS data of COSMIC and GRACE satellite missions. The kinematic orbits of COSMIC and GRACE are determined to the cm-level accuracy. The NASA Goddard's GEODYN II software is used to model the orbit dynamics of COSMIC and GRACE, including the effect of a static gravity field. The surface forces are estimated per one orbital period. Residual orbits generated from kinematic and reference orbits serve as observables to determine the harmonic coefficients in the weighted-constraint least-squares. The monthly COSMIC and GRACE GPS data from September 2006 to December 2007 (16 months) are processed to estimate harmonic coefficients to degree 5. The geoid variations from the GPS and CSR RL04 (GRACE) solutions show consistent patterns over space and time, especially in regions of active hydrological changes. The monthly GPS-derived second zonal coefficient closely resembles the SLR-derived and CSR RL04 values, and third and fourth zonal coefficients resemble the CSR RL04 values.

  1. Assimilating GRACE terrestrial water storage data into a conceptual hydrology model for the River Rhine

    Science.gov (United States)

    Widiastuti, E.; Steele-Dunne, S. C.; Gunter, B.; Weerts, A.; van de Giesen, N.

    2009-12-01

    Terrestrial water storage (TWS) is a key component of the terrestrial and global hydrological cycles, and plays a major role in the Earth’s climate. The Gravity Recovery and Climate Experiment (GRACE) twin satellite mission provided the first space-based dataset of TWS variations, albeit with coarse resolution and limited accuracy. Here, we examine the value of assimilating GRACE observations into a well-calibrated conceptual hydrology model of the Rhine river basin. In this study, the ensemble Kalman filter (EnKF) and smoother (EnKS) were applied to assimilate the GRACE TWS variation data into the HBV-96 rainfall run-off model, from February 2003 to December 2006. Two GRACE datasets were used, the DMT-1 models produced at TU Delft, and the CSR-RL04 models produced by UT-Austin . Each center uses its own data processing and filtering methods, yielding two different estimates of TWS variations and therefore two sets of assimilated TWS estimates. To validate the results, the model estimated discharge after the data assimilation was compared with measured discharge at several stations. As expected, the updated TWS was generally somewhere between the modeled and observed TWS in both experiments and the variance was also lower than both the prior error covariance and the assumed GRACE observation error. However, the impact on the discharge was found to depend heavily on the assimilation strategy used, in particular on how the TWS increments were applied to the individual storage terms of the hydrology model.

  2. Capital Grace of the Word Incarnate According to Saint Thomas Aquinas

    Directory of Open Access Journals (Sweden)

    Lucia Marie Siemering

    2016-06-01

    Full Text Available The doctrine of capital grace was developed during the Scholastic period and bears on many areas of theology including ecclesiology, Christology, sacraments, and Trinitarian theology with regard to the missions of the Word and the Holy Spirit. Viewed from a Christological standpoint, capital grace sheds light on how Christ in his human nature can be said to be a source of grace to the members of the Church. Following his contemporaries, the young Thomas Aquinas espoused a view in which Christ is a meritorious, ministerial, and dispositive cause of grace according to his human nature, and an efficient cause according to his divinity. After a deeper reading of John Damascene’s treatment of Christ’s humanity being an instrument of his divinity, Thomas was able to articulate a view in which Christ’s human nature is an instrumental efficient cause of grace. This view undergirds Aquinas’s strong conception of Christ as one acting person in two natures.

  3. NOAA's Joint Polar Satellite System's (JPSS) Proving Ground and Risk Reduction (PGRR) Program - Bringing JPSS Science into Support of Key NOAA Missions!

    Science.gov (United States)

    Sjoberg, W.; McWilliams, G.

    2017-12-01

    This presentation will focus on the continuity of the NOAA Joint Polar Satellite System (JPSS) Program's Proving Ground and Risk Reduction (PGRR) and key activities of the PGRR Initiatives. The PGRR Program was established in 2012, following the launch of the Suomi National Polar Partnership (SNPP) satellite. The JPSS Program Office has used two PGRR Project Proposals to establish an effective approach to managing its science and algorithm teams in order to focus on key NOAA missions. The presenter will provide details of the Initiatives and the processes used by the initiatives that have proven so successful. Details of the new 2017 PGRR Call-for-Proposals and the status of project selections will be discussed.

  4. Time-variations of equivalent water heights'from Grace Mission and in-situ river stages in the Amazon basin Variações temporais do equivalente à altura d'água obtidas da Missão Grace e da altura d'água in-situ nos rios da bacia Amazônica

    Directory of Open Access Journals (Sweden)

    Flavio Guilherme Vaz de Almeida

    2012-03-01

    Full Text Available Gravity Recovery and Climate Experiment (GRACE mission is dedicated to measuring temporal variations of the Earth's gravity field. In this study, the Stokes coefficients made available by Groupe de Recherche en Géodésie Spatiale (GRGS at a 10-day interval were converted into equivalent water height (EWH for a ~4-year period in the Amazon basin (from July-2002 to May-2006. The seasonal amplitudes of EWH signal are the largest on the surface of Earth and reach ~ 1250mm at that basin's center. Error budget represents ~130 mm of EWH, including formal errors on Stokes coefficient, leakage errors (12 ~ 21 mm and spectrum truncation (10 ~ 15 mm. Comparison between in situ river level time series measured at 233 ground-based hydrometric stations (HS in the Amazon basin and vertically-integrated EWH derived from GRACE is carried out in this paper. Although EWH and HS measure different water bodies, in most of the cases a high correlation (up to ~80% is detected between the HS series and EWH series at the same site. This correlation allows adjusting linear relationships between in situ and GRACE-based series for the major tributaries of the Amazon river. The regression coefficients decrease from up to down stream along the rivers reaching the theoretical value 1 at the Amazon's mouth in the Atlantic Ocean. The variation of the regression coefficients versus the distance from estuary is analysed for the largest rivers in the basin. In a second step, a classification of the proportionality between in situ and GRACE time-series is proposed.A missão espacial Gravity Recovery and Climate Experiment (GRACE é dedicada às medidas das variações temporais no campo gravitacional da Terra. Neste estudo, os coeficientes de Stokes disponibilizados pelo Groupe de Recherche en Géodésie Spatiale (GRGS com intervalos de 10 dias foram convertidos no equivalente à altura d'água (EWH para um período de 4 anos na bacia Amazônica (de julho de 2002 a maio de 2006

  5. Grace and Courtesy: A Human Responsibility. AMI/USA Conference (Oak Brook, Illinois, July 23-26, 1998).

    Science.gov (United States)

    American Montessori International of the United States, Inc., Rochester, NY.

    This conference proceedings compile presentations from a 1998 meeting of the American Montessori International of the United States, focusing on the importance of grace and courtesy in children's lives and in Montessori education. The papers presented are: (1) "Grace--The Felicity of Being" (Renilde Montessori); (2) "A Montessori…

  6. Surface mass redistribution inversion from global GPS deformation and Gravity Recovery and Climate Experiment (GRACE) gravity data

    NARCIS (Netherlands)

    Kusche, J.; Schrama, E.J.O.

    2005-01-01

    Monitoring hydrological redistributions through their integrated gravitational effect is the primary aim of the Gravity Recovery and Climate Experiment (GRACE) mission. Time?variable gravity data from GRACE can be uniquely inverted to hydrology, since mass transfers located at or near the Earth's

  7. Sensitivity of the Gravity Recovery and Climate Experiment (GRACE) to the complexity of aquifer systems for monitoring of groundwater

    Science.gov (United States)

    Katpatal, Yashwant B.; Rishma, C.; Singh, Chandan K.

    2018-05-01

    The Gravity Recovery and Climate Experiment (GRACE) satellite mission is aimed at assessment of groundwater storage under different terrestrial conditions. The main objective of the presented study is to highlight the significance of aquifer complexity to improve the performance of GRACE in monitoring groundwater. Vidarbha region of Maharashtra, central India, was selected as the study area for analysis, since the region comprises a simple aquifer system in the western region and a complex aquifer system in the eastern region. Groundwater-level-trend analyses of the different aquifer systems and spatial and temporal variation of the terrestrial water storage anomaly were studied to understand the groundwater scenario. GRACE and its field application involve selecting four pixels from the GRACE output with different aquifer systems, where each GRACE pixel encompasses 50-90 monitoring wells. Groundwater storage anomalies (GWSA) are derived for each pixel for the period 2002 to 2015 using the Release 05 (RL05) monthly GRACE gravity models and the Global Land Data Assimilation System (GLDAS) land-surface models (GWSAGRACE) as well as the actual field data (GWSAActual). Correlation analysis between GWSAGRACE and GWSAActual was performed using linear regression. The Pearson and Spearman methods show that the performance of GRACE is good in the region with simple aquifers; however, performance is poorer in the region with multiple aquifer systems. The study highlights the importance of incorporating the sensitivity of GRACE in estimation of groundwater storage in complex aquifer systems in future studies.

  8. "A Prairie Childhood" by Edith Abbott: An Excerpt from "The Children's Champion," a Biography of Grace Abbott

    Science.gov (United States)

    Sorensen, John

    2003-01-01

    Grace Abbott's courageous struggles--to protect the rights of immigrants, to increase the role of women in government, and to improve the lives of all children--are filled with adventurous tales of the remarkable human ability to seek out suffering and to do something about it. "A Prairie Childhood" is an excerpt from the Grace Abbott biography…

  9. Statistically optimal estimation of Greenland Ice Sheet mass variations from GRACE monthly solutions using an improved mascon approach

    NARCIS (Netherlands)

    Ran, J.; Ditmar, P.G.; Klees, R.; Farahani, H.

    2017-01-01

    We present an improved mascon approach to transform monthly spherical harmonic solutions based on GRACE satellite data into mass anomaly estimates in Greenland. The GRACE-based spherical harmonic coefficients are used to synthesize gravity anomalies at satellite altitude, which are then inverted

  10. Development of KSC program for investigating and generating field failure rates. Reliability handbook for ground support equipment

    Science.gov (United States)

    Bloomquist, C. E.; Kallmeyer, R. H.

    1972-01-01

    Field failure rates and confidence factors are presented for 88 identifiable components of the ground support equipment at the John F. Kennedy Space Center. For most of these, supplementary information regarding failure mode and cause is tabulated. Complete reliability assessments are included for three systems, eight subsystems, and nine generic piece-part classifications. Procedures for updating or augmenting the reliability results are also included.

  11. NRC Task Force report on review of the federal/state program for regulation of commercial low-level radioactive waste burial grounds

    International Nuclear Information System (INIS)

    1977-01-01

    The underlying issue explored in this report is that of Federal vs State regulation of commercial radioactive waste burial grounds. The need for research and development, a comprehensive set of standards and criteria, a national plan for low-level waste management, and perpetual care funding are closely related to the central issue and are also discussed. Five of the six commercial burial grounds are regulated by Agreement States; the sixth is regulated solely by the NRC (NRC also regulates Special Nuclear Material at the sites). The sites are operated commercially. The operators contribute to the perpetual care funds for the sites at varying rates. The States have commitments for the perpetual care of the decommissioned sites except for one site, located on Federally owned land. Three conclusions are reached. Federal control over the disposal of low-level waste should be increased by requiring joint Federal/State site approval, NRC licensing, Federal ownership of the land, and a Federally administered perpetual care program. The NRC should accelerate the development of its regulatory program for the disposal of low-level waste. The undisciplined proliferation of low-level burial sites must be avoided. NRC should evaluate alternative disposal methods, conduct necessary studies, and develop a comprehensive low-level waste regulatory program (i.e., accomplish the above recommendations) prior to the licensing of new disposal sites

  12. Mass balance of Greenland and the Canadian Ice Caps from combined altimetry and GRACE inversion

    DEFF Research Database (Denmark)

    Forsberg, René; Simonsen, Sebastian Bjerregaard; Sørensen, Louise Sandberg

    The combination of GRACE and altimetry data may yield a high resolution mass balance time series of the Greenlandice sheet, highlighting the varying individual mass loss behaviour of major glaciers. By including the Canadian arctic ice caps in the estimation, a more reliable estimate of the mass...... loss of both Greenlandand the Canadian ice caps may be obtained, minimizing the leakage errors otherwise unavoidable by GRACE. Actually, the absolute value of the Greenlandice sheet mass loss is highly dependent on methods and how the effects of Arctic Canadian ice caps are separated in the GRACE...... loss of the ice caps and ice sheet basins for the period 2003-15. This period shows a marked increase of ice sheet melt, especially in NW and NE Greenland, but also show large variability, with the melt anomaly year of 2012 showing a record mass loss, followed by 2013 with essentially no Greenland mass...

  13. Large scale mass redistribution and surface displacement from GRACE and SLR

    Science.gov (United States)

    Cheng, M.; Ries, J. C.; Tapley, B. D.

    2012-12-01

    Mass transport between the atmosphere, ocean and solid earth results in the temporal variations in the Earth gravity field and loading induced deformation of the Earth. Recent space-borne observations, such as GRACE mission, are providing extremely high precision temporal variations of gravity field. The results from 10-yr GRACE data has shown a significant annual variations of large scale vertical and horizontal displacements occurring over the Amazon, Himalayan region and South Asia, African, and Russian with a few mm amplitude. Improving understanding from monitoring and modeling of the large scale mass redistribution and the Earth's response are a critical for all studies in the geosciences, in particular for determination of Terrestrial Reference System (TRS), including geocenter motion. This paper will report results for the observed seasonal variations in the 3-dimentional surface displacements of SLR and GPS tracking stations and compare with the prediction from time series of GRACE monthly gravity solution.

  14. Request for personal participation of the salvific grace in the celebration of the sacred sacraments

    Directory of Open Access Journals (Sweden)

    Jan Szczych

    2016-06-01

    Full Text Available It is through the participation of the faithful in the sacramental liturgies of the Church that salvation is accomplished. The faithful, desirous of a supernatural relationship with God, through their own life experience endeavor to actively translate into practice the mystery of Christ’s salvific grace. For this reason, the words pronounced by the person when first requesting the grace of any sacrament, either for themselves or on someone else’s behalf, find their full justification when repeated during the actual ceremony. Intentional request for the concession of any sacrament, which enables a personal participation of Christ’s grace, is a result of Christian faith, and activates a conscious and fruitful participation in the redeeming sacrifice of Christ.

  15. Spread of ice mass loss into northwest Greenland observed by GRACE and GPS

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Wahr, John; Bevis, Michael

    2010-01-01

    Global Positioning System (GPS) measurements from three long-term sites on bedrock adjacent to the ice sheet. The GRACE results provide a direct measure of mass loss averaged over scales of a few hundred km. The GPS data are used to monitor crustal uplift caused by ice mass loss close to the sites....... The GRACE results can be used to predict crustal uplift, which can be compared with the GPS data. In addition to showing that the northwest ice sheet margin is now losing mass, the uplift results from both the GPS measurements and the GRACE predictions show rapid acceleration in southeast Greenland in late...... 2003, followed by a moderate deceleration in 2006. Because that latter deceleration is weak, southeast Greenland still appears to be losing ice mass at a much higher rate than it was prior to fall 2003. In a more general sense, the analysis described here demonstrates that GPS uplift measurements can...

  16. A Record-High Ocean Bottom Pressure in the South Pacific Observed by GRACE

    Science.gov (United States)

    Boening, Carmen; Lee, Tong; Zlotnicki, Victor

    2011-01-01

    In late 2009 to early 2010, the Gravity Recovery and Climate Experiment (GRACE) satellite pair observed a record increase in ocean bottom pressure (OBP) over a large mid-latitude region of the South East Pacific. Its magnitude is substantially larger than other oceanic events in the Southern Hemisphere found in the entire GRACE data records (2003-2010) on multi-month time scales. The OBP data help to understand the nature of a similar signal in sea surface height (SSH) anomaly observed by altimetry: the SSH increase is mainly due to mass convergence. Analysis of the barotropic vorticity equation using scatterometer data, atmospheric reanalysis product, and GRACE and altimeter an atmospheric reanalysis product observations suggests that the observed OBP/SSH signal was primarily caused by wind stress curl associated with a strong and persistent anticyclone in late 2009 in combination with effects of planetary vorticity gradient, bottom topography, and friction

  17. Predictive modeling of cholera using GRACE and TRMM satellite data

    Science.gov (United States)

    Jutla, A.; Akanda, A. S. S.; Colwell, R. R.

    2015-12-01

    Cholera outbreaks can be classified in three forms- epidemic (sudden or seasonal outbreaks), endemic (recurrence and persistence of the disease for several consecutive years) and mixed-mode endemic (combination of certain epidemic and endemic conditions) with significant spatial and temporal heterogeneity. Endemic cholera is related to floods and droughts in regions where water and sanitation infrastructure are inadequate or insufficient. With more than a decade of terrestrial water storage (TWS) data obtained from Gravity Recovery and Climate Experiment (GRACE), understanding dynamics of river discharge is now feasible. We explored lead-lag relationships between TWS in the Ganges-Brahmaputra-Meghna (GBM) basin and endemic cholera in Bangladesh. Since bimodal seasonal peaks in cholera in Bangladesh occur during the spring and autumn season, two separate models, between TWS and disease time series (2002 to 2010) were developed. TWS, hence water availability, showed an asymmetrical, strong association with spring (τ=-0.53; pcholera prevalence up to five to six months in advance. One unit (cm of water) decrease in water availability in the basin increased odds of above normal cholera by 24% [confidence interval (CI) 20-31%; pcholera in the autumn by 29% [CI:22-33%; pcholera is related with warm temperatures and heavy rainfall. Using TRMM data for several locations in Asia and Africa, probability of cholera increases 18% [CI:15-23%; p<0.05] after heavy precipitation resulted in a societal conditions where access to safe water and sanitation was disrupted. Results from mechanistic modeling framework using systems approach that include satellite based hydroclimatic information with tradition disease transmission models will also be presented.

  18. Comparison of observed and modeled seasonal crustal vertical displacements derived from multi-institution GPS and GRACE solutions

    Science.gov (United States)

    Gu, Yanchao; Fan, Dongming; You, Wei

    2017-07-01

    Eleven GPS crustal vertical displacement (CVD) solutions for 110 IGS08/IGS14 core stations provided by the International Global Navigation Satellite Systems Service Analysis Centers are compared with seven Gravity Recovery and Climate Experiment (GRACE)-modeled CVD solutions. The results of the internal comparison of the GPS solutions from multiple institutions imply large uncertainty in the GPS postprocessing. There is also evidence that GRACE solutions from both different institutions and different processing approaches (mascon and traditional spherical harmonic coefficients) show similar results, suggesting that GRACE can provide CVD results of good internal consistency. When the uncertainty of the GPS data is accounted for, the GRACE data can explain as much as 50% of the actual signals and more than 80% of the GPS annual signals. Our study strongly indicates that GRACE data have great potential to correct the nontidal loading in GPS time series.

  19. On Common Constitutional Ground: How Georgia's Scholarship Tax Credits Mirror Other State Programs and Expand Educational Opportunity

    Science.gov (United States)

    Carpenter, Dick M., II.; Erickson, Angela C.

    2016-01-01

    In 2008, Georgia launched a tax-credit scholarship program to expand educational opportunities for the state's pre-K through 12th-grade students by providing them scholarships to attend private schools. Georgia's scholarship tax credit program will help over 13,000 children get the best education for their needs at secular and religious private…

  20. Human-induced Terrestrial Water Storage Change: A Global Analysis using Hydrological Models and GRACE

    Science.gov (United States)

    Felfelani, F.; Pokhrel, Y. N.

    2016-12-01

    Hydrological models and data derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are used to study terrestrial water storage (TWS) change; however, both have disadvantages that necessitate the integrated use of them. While GRACE doesn't disintegrate the vertical storage into its components, most models do not account for human activities. Here we use two Land Surface Models (LSMs), i.e., HiGW-MAT and PCRGLOBWB that fully couple natural and human drivers of changes in water cycle, explicitly simulating the changes in various TWS compartments. We first evaluate the models performance with GRACE observations. Then, we quantify the human footprint over global river basins located in different geographic and climate regions. To quantify human impacts, a new framework is proposed based on the GRACE observations (representing both climate variability and human activities) together with the natural simulation of LSMs using water budget equation (P-ET-R; P for precipitation, ET for evapotranspiration, and R for runoff). Finally, we examine the uncertainty in TWS simulations arising from the uncertainties in forcing data. Results indicate that, in snow-dominated regions, PCRGLOBWB generally fails to reproduce neither the interannual variability of observed TWS nor the seasonal cycle, while HiGW-MAT model shows significantly better results. In basins with human signatures, PCRGLOBWB generally shows better agreement with GRACE compared to HiGW-MAT. It is found that HiGW-MAT tends to overestimate groundwater depletion in basins with human impacts (e.g., Amudarya, Colorado, Euphrates and Indus), which results in larger negative interannual TWS trend compared to GRACE. Euphrates and Ganges river basins experience the highest human-induced TWS deficit rates (2.08 cm/yr and 1.94 cm/yr, respectively) during the simulation period of 2002-2010. Uncertainty analysis of results from the same model but with different forcing data suggests a high standard

  1. Comparison of Decadal Water Storage Trends from Global Hydrological Models and GRACE Satellite Data

    Science.gov (United States)

    Scanlon, B. R.; Zhang, Z. Z.; Save, H.; Sun, A. Y.; Mueller Schmied, H.; Van Beek, L. P.; Wiese, D. N.; Wada, Y.; Long, D.; Reedy, R. C.; Doll, P. M.; Longuevergne, L.

    2017-12-01

    Global hydrology is increasingly being evaluated using models; however, the reliability of these global models is not well known. In this study we compared decadal trends (2002-2014) in land water storage from 7 global models (WGHM, PCR-GLOBWB, and GLDAS: NOAH, MOSAIC, VIC, CLM, and CLSM) to storage trends from new GRACE satellite mascon solutions (CSR-M and JPL-M). The analysis was conducted over 186 river basins, representing about 60% of the global land area. Modeled total water storage trends agree with those from GRACE-derived trends that are within ±0.5 km3/yr but greatly underestimate large declining and rising trends outside this range. Large declining trends are found mostly in intensively irrigated basins and in some basins in northern latitudes. Rising trends are found in basins with little or no irrigation and are generally related to increasing trends in precipitation. The largest decline is found in the Ganges (-12 km3/yr) and the largest rise in the Amazon (43 km3/yr). Differences between models and GRACE are greatest in large basins (>0.5x106 km2) mostly in humid regions. There is very little agreement in storage trends between models and GRACE and among the models with values of r2 mostly store water over decadal timescales that is underrepresented by the models. The storage capacity in the modeled soil and groundwater compartments may be insufficient to accommodate the range in water storage variations shown by GRACE data. The inability of the models to capture the large storage trends indicates that model projections of climate and human-induced changes in water storage may be mostly underestimated. Future GRACE and model studies should try to reduce the various sources of uncertainty in water storage trends and should consider expanding the modeled storage capacity of the soil profiles and their interaction with groundwater.

  2. Prognostic Accuracy of the GRACE Score in Octogenarians and Nonagenarians with Acute Coronary Syndromes

    Directory of Open Access Journals (Sweden)

    Antonio Mauricio dos Santos Cerqueira Junior

    2018-02-01

    Full Text Available Abstract Background: The GRACE Score was derived and validated from a cohort in which octogenarians and nonagenarians were poorly represented. Objective: To test the accuracy of the GRACE score in predicting in-hospital mortality of very elderly individuals with acute coronary syndromes (ACS. Methods: Prospective observational study conducted in the intensive coronary care unit of a tertiary center from September 2011 to August 2016. Patients consecutively admitted due to ACS were selected, and the very elderly group was defined by age ≥ 80 years. The GRACE Score was based on admission data and its accuracy was tested regarding prediction of in-hospital death. Statistical significance was defined by p value < 0,05. Results: A total of 994 individuals was studied, 57% male, 77% with non-ST elevation myocardial infarction and 173 (17% very elderly patients. The mean age of the sample was 65 ± 13 years, and the mean age of very elderly patients subgroup was 85 ± 3.7 years. The C-statistics of the GRACE Score in very elderly patients was 0.86 (95% CI = 0.78 - 0.93, with no difference when compared to the value for younger individuals 0.83 (95% CI = 0.75 - 0.91, with p = 0.69. The calibration of the score in very elderly patients was described by χ2 test of Hosmer-Lemeshow = 2.2 (p = 0.98, while the remaining patients presented χ2 = 9.0 (p = 0.35. Logistic regression analysis for death prediction did not show interaction between GRACE Score and variable of very elderly patients (p = 0.25. Conclusion: The GRACE Score in very elderly patients is accurate in predicting in-hospital ACS mortality, similarly to younger patients.

  3. Radial and tangential gravity rates from GRACE in areas of glacial isostatic adjustment

    Science.gov (United States)

    van der Wal, Wouter; Kurtenbach, Enrico; Kusche, Jürgen; Vermeersen, Bert

    2011-11-01

    In areas dominated by Glacial Isostatic Adjustment (GIA), the free-air gravity anomaly rate can be converted to uplift rate to good approximation by using a simple spectral relation. We provide quantitative comparisons between gravity rates derived from monthly gravity field solutions (GFZ Potsdam, CSR Texas, IGG Bonn) from the Gravity Recovery and Climate Experiment (GRACE) satellite mission with uplift rates measured by GPS in these areas. The band-limited gravity data from the GRACE satellite mission can be brought to very good agreement with the point data from GPS by using scaling factors derived from a GIA model (the root-mean-square of differences is 0.55 mm yr-1 for a maximum uplift rate signal of 10 mm yr-1). The root-mean-square of the differences between GRACE derived uplift rates and GPS derived uplift rates decreases with increasing GRACE time period to a level below the uncertainty that is expected from GRACE observations, GPS measurements and the conversion from gravity rate to uplift rate. With the current length of time-series (more than 8 yr) applying filters and a hydrology correction to the GRACE data does not reduce the root-mean-square of differences significantly. The smallest root-mean-square was obtained with the GFZ solution in Fennoscandia and with the CSR solution in North America. With radial gravity rates in excellent agreement with GPS uplift rates, more information on the GIA process can be extracted from GRACE gravity field solutions in the form of tangential gravity rates, which are equivalent to a rate of change in the deflection of the vertical scaled by the magnitude of gravity rate vector. Tangential gravity rates derived from GRACE point towards the centre of the previously glaciated area, and are largest in a location close to the centre of the former ice sheet. Forward modelling showed that present day tangential gravity rates have maximum sensitivity between the centre and edge of the former ice sheet, while radial gravity

  4. Resolving mass flux at high spatial and temporal resolution using GRACE intersatellite measurements

    DEFF Research Database (Denmark)

    Rowlands, D. D.; Luthcke, S. B.; Klosko, S. M.

    2005-01-01

    resolution. Using 4° × 4° blocks at 10-day intervals, we estimate the mass of surplus or deficit water over a 52° × 60° grid centered on the Amazon basin for July 2003. We demonstrate that the recovered signals are coherent and correlate well with the expected hydrological signal....... the estimation of static monthly parameters. Through an analysis of the GRACE data residuals, we show that the fundamental temporal and spatial resolution of the GRACE data is 10 days and 400 km. We present an approach similar in concept to altimetric methods that recovers submonthly mass flux at a high spatial...

  5. A Comparison of Two Commercial Volumetry Software Programs in the Analysis of Pulmonary Ground-Glass Nodules: Segmentation Capability and Measurement Accuracy

    Science.gov (United States)

    Kim, Hyungjin; Lee, Sang Min; Lee, Hyun-Ju; Goo, Jin Mo

    2013-01-01

    Objective To compare the segmentation capability of the 2 currently available commercial volumetry software programs with specific segmentation algorithms for pulmonary ground-glass nodules (GGNs) and to assess their measurement accuracy. Materials and Methods In this study, 55 patients with 66 GGNs underwent unenhanced low-dose CT. GGN segmentation was performed by using 2 volumetry software programs (LungCARE, Siemens Healthcare; LungVCAR, GE Healthcare). Successful nodule segmentation was assessed visually and morphologic features of GGNs were evaluated to determine factors affecting segmentation by both types of software. In addition, the measurement accuracy of the software programs was investigated by using an anthropomorphic chest phantom containing simulated GGNs. Results The successful nodule segmentation rate was significantly higher in LungCARE (90.9%) than in LungVCAR (72.7%) (p = 0.012). Vascular attachment was a negatively influencing morphologic feature of nodule segmentation for both software programs. As for measurement accuracy, mean relative volume measurement errors in nodules ≥ 10 mm were 14.89% with LungCARE and 19.96% with LungVCAR. The mean relative attenuation measurement errors in nodules ≥ 10 mm were 3.03% with LungCARE and 5.12% with LungVCAR. Conclusion LungCARE shows significantly higher segmentation success rates than LungVCAR. Measurement accuracy of volume and attenuation of GGNs is acceptable in GGNs ≥ 10 mm by both software programs. PMID:23901328

  6. A comparison of two commercial volumetry software programs in the analysis of pulmonary ground-glass nodules: Segmentation capability and measurement accuracy

    International Nuclear Information System (INIS)

    Kim, Hyung Jin; Park, Chang Min; Lee, Sang Min; Lee, Hyun Joo; Goo, Jin Mo

    2013-01-01

    To compare the segmentation capability of the 2 currently available commercial volumetry software programs with specific segmentation algorithms for pulmonary ground-glass nodules (GGNs) and to assess their measurement accuracy. In this study, 55 patients with 66 GGNs underwent unenhanced low-dose CT. GGN segmentation was performed by using 2 volumetry software programs (LungCARE, Siemens Healthcare; LungVCAR, GE Healthcare). Successful nodule segmentation was assessed visually and morphologic features of GGNs were evaluated to determine factors affecting segmentation by both types of software. In addition, the measurement accuracy of the software programs was investigated by using an anthropomorphic chest phantom containing simulated GGNs. The successful nodule segmentation rate was significantly higher in LungCARE (90.9%) than in LungVCAR (72.7%) (p = 0.012). Vascular attachment was a negatively influencing morphologic feature of nodule segmentation for both software programs. As for measurement accuracy, mean relative volume measurement errors in nodules ≥ 10 mm were 14.89% with LungCARE and 19.96% with LungVCAR. The mean relative attenuation measurement errors in nodules ≥ 10 mm were 3.03% with LungCARE and 5.12% with LungVCAR. LungCARE shows significantly higher segmentation success rates than LungVCAR. Measurement accuracy of volume and attenuation of GGNs is acceptable in GGNs ≥ 10 mm by both software programs.

  7. A comparison of two commercial volumetry software programs in the analysis of pulmonary ground-glass nodules: Segmentation capability and measurement accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Jin; Park, Chang Min; Lee, Sang Min; Lee, Hyun Joo; Goo, Jin Mo [Dept. of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul (Korea, Republic of)

    2013-08-15

    To compare the segmentation capability of the 2 currently available commercial volumetry software programs with specific segmentation algorithms for pulmonary ground-glass nodules (GGNs) and to assess their measurement accuracy. In this study, 55 patients with 66 GGNs underwent unenhanced low-dose CT. GGN segmentation was performed by using 2 volumetry software programs (LungCARE, Siemens Healthcare; LungVCAR, GE Healthcare). Successful nodule segmentation was assessed visually and morphologic features of GGNs were evaluated to determine factors affecting segmentation by both types of software. In addition, the measurement accuracy of the software programs was investigated by using an anthropomorphic chest phantom containing simulated GGNs. The successful nodule segmentation rate was significantly higher in LungCARE (90.9%) than in LungVCAR (72.7%) (p = 0.012). Vascular attachment was a negatively influencing morphologic feature of nodule segmentation for both software programs. As for measurement accuracy, mean relative volume measurement errors in nodules ≥ 10 mm were 14.89% with LungCARE and 19.96% with LungVCAR. The mean relative attenuation measurement errors in nodules ≥ 10 mm were 3.03% with LungCARE and 5.12% with LungVCAR. LungCARE shows significantly higher segmentation success rates than LungVCAR. Measurement accuracy of volume and attenuation of GGNs is acceptable in GGNs ≥ 10 mm by both software programs.

  8. An Evaluation of the Availability and Application of Microcomputer Software Programs for Use in Air Force Ground Transportation Squadrons

    Science.gov (United States)

    1988-09-01

    software programs capable of being used on a microcomputer will be considered for analysis. No software intended for use on a miniframe or mainframe...Dial-A-Log consists of a program written in a computer language called L-10 that is run on a DEC-20 miniframe . The combination of the specific...proliferation of software dealing with microcomputers. Instead, they were geared more towards managing the use of miniframe or mainframe computer

  9. Analysis of the altitudinal structure of Storm-enhanced density using Total Electron Content data of space-borne and ground-based GPS receivers

    Directory of Open Access Journals (Sweden)

    Yukari Goi

    2013-11-01

    Full Text Available The altitudinal structure of Storm-enhanced density (SED was studied using the Total Electron Content (TEC data of the GPS receiver on the Gravity Recovery and Climate Experiment (GRACE satellite and the ground-based GPS receivers. The GRACETEC-data are derived from the GPS receiver on the GRACE satellite. A SED is a high-electron density phenomenon that extends from the Equatorial Ionization Anomaly (EIA toward the north-west in the northern hemisphere during geomagnetic disturbed time. TwoSEDs were observed as TEC variations in the GRACE-TEC data and in the ground-GPS TEC data. The ground-GPS TEC data is the TEC data between the ground GPS receiver and the GPS satellites. The SED observed in the GRACE-TEC data appeared at higher latitudes than that in the ground-GPS TEC data. We concluded detected that the altitudinal structure of the SED would be different between at lower than at higher latitudes due to the effects of the eastward E×B drift.

  10. Ground-Water Quality Data in the Owens and Indian Wells Valleys Study Unit, 2006: Results from the California GAMA Program

    Science.gov (United States)

    Densmore, Jill N.; Fram, Miranda S.; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 1,630 square-mile Owens and Indian Wells Valleys study unit (OWENS) was investigated in September-December 2006 as part of the Priority Basin Project of Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in collaboration with the California State Water Resources Control Board (SWRCB). The Owens and Indian Wells Valleys study was designed to provide a spatially unbiased assessment of raw ground-water quality within OWENS study unit, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 74 wells in Inyo, Kern, Mono, and San Bernardino Counties. Fifty-three of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and 21 wells were selected to evaluate changes in water chemistry in areas of interest (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates, pharmaceutical compounds, and potential wastewater- indicator compounds], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), and 1,2,3- trichloropropane (1,2,3-TCP)], naturally occurring inorganic constituents [nutrients, major and minor ions, and trace elements], radioactive constituents, and microbial indicators. Naturally occurring isotopes [tritium, and carbon-14, and stable isotopes of hydrogen and oxygen in water], and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. This study evaluated the quality of raw ground water in the aquifer in the OWENS study unit and did not attempt to evaluate the quality of treated water

  11. Compilation, assessment and expansion of the strong earthquake ground motion data base. Seismic Safety Margins Research Program (SSMRP)

    International Nuclear Information System (INIS)

    Crouse, C.B.; Hileman, J.A.; Turner, B.E.; Martin, G.R.

    1980-09-01

    A catalog has been prepared which contains information for: (1) world-wide, ground-motion accelerograms (2) the accelerograph sites where these records were obtained, and (3) the seismological parameters of the causative earthquakes. The catalog is limited to data for those accelerograms which have been digitized and published. In addition, the quality and completeness of these data are assessed. This catalog is unique because it is the only publication which contains comprehensive information on the recording conditions of all known digitized accelerograms. However, information for many accelerograms is missing. Although some literature may have been overlooked, most of the missing data has not been published. Nevertheless, the catalog provides a convenient reference and useful tool for earthquake engineering research and applications. (author)

  12. PRECONDITIONED CONJUGATE-GRADIENT 2 (PCG2), a computer program for solving ground-water flow equations

    Science.gov (United States)

    Hill, Mary C.

    1990-01-01

    This report documents PCG2 : a numerical code to be used with the U.S. Geological Survey modular three-dimensional, finite-difference, ground-water flow model . PCG2 uses the preconditioned conjugate-gradient method to solve the equations produced by the model for hydraulic head. Linear or nonlinear flow conditions may be simulated. PCG2 includes two reconditioning options : modified incomplete Cholesky preconditioning, which is efficient on scalar computers; and polynomial preconditioning, which requires less computer storage and, with modifications that depend on the computer used, is most efficient on vector computers . Convergence of the solver is determined using both head-change and residual criteria. Nonlinear problems are solved using Picard iterations. This documentation provides a description of the preconditioned conjugate gradient method and the two preconditioners, detailed instructions for linking PCG2 to the modular model, sample data inputs, a brief description of PCG2, and a FORTRAN listing.

  13. Grounded theory.

    Science.gov (United States)

    Harris, Tina

    2015-04-29

    Grounded theory is a popular research approach in health care and the social sciences. This article provides a description of grounded theory methodology and its key components, using examples from published studies to demonstrate practical application. It aims to demystify grounded theory for novice nurse researchers, by explaining what it is, when to use it, why they would want to use it and how to use it. It should enable nurse researchers to decide if grounded theory is an appropriate approach for their research, and to determine the quality of any grounded theory research they read.

  14. A comparison of annual vertical crustal displacements from GPS and Gravity Recovery and Climate Experiment (GRACE) over Europe

    Science.gov (United States)

    van Dam, T.; Wahr, J.; LavalléE, David

    2007-03-01

    We compare approximately 3 years of GPS height residuals (with respect to the International Terrestrial Reference Frame) with predictions of vertical surface displacements derived from the Gravity Recovery and Climate Experiment (GRACE) gravity fields for stations in Europe. An annual signal fit to the residual monthly heights, corrected for atmospheric pressure and barotropic ocean loading effects, should primarily represent surface displacements due to long-wavelength variations in water storage. A comparison of the annual height signal from GPS and GRACE over Europe indicates that at most sites, the annual signals do not agree in amplitude or phase. We find that unlike the annual signal predicted from GRACE, the annual signal in the GPS heights is not coherent over the region, displaying significant variability from site to site. Confidence in the GRACE data and the unlikely possibility of large-amplitude small-scale features in the load field not captured by the GRACE data leads us to conclude that some of the discrepancy between the GPS and GRACE observations is due to technique errors in the GPS data processing. This is evidenced by the fact that the disagreement between GPS and GRACE is largest at coastal sites, where mismodeling of the semidiurnal ocean tidal loading signal can result in spurious annual signals.

  15. Glacial isostatic adjustment on the Northern Hemisphere - new results from GRACE

    Science.gov (United States)

    Mueller, J.; Steffen, H.; Gitlein, O.; Denker, H.; Timmen, L.

    2007-12-01

    The Earth's gravity field mapped by the Gravity Recovery and Climate Experiment (GRACE) satellite mission shows variations due to the integral effect of mass variations in the atmosphere, hydrosphere and geosphere. The Earth's gravity field is provided in form of monthly solutions by several institutions, e.~g. GFZ Potsdam, CSR and JPL. During the GRACE standard processing of these analysis centers, oceanic and atmospheric contributions as well as tidal effects are reduced. The solutions of the analysis centers differ slightly, which is due the application of different reduction models and center-specific processing schemes. We present our investigation of mass variations in the areas of glacial isostatic adjustment (GIA) in North America and Northern Europe from GRACE data. One key issue is the separation of GIA parts and the reduction of the observed quantities by applying dedicated filters (e.~g. isotropic, non-isotropic, and destriping filters) and global models of hydrological variations (e.~g. WGHM, LaDWorld, GLDAS). In a further step, we analyze the results of both regions regarding their reliability, and finally present a comparison to results of a geodynamical modeling and absolute gravity measurements. Our results clearly show that the quality of the GRACE-derived gravity- change signal benefits from improved reduction models and chosen analysis techniques. Nevertheless, the comparison to results of geodynamic models still reveals differences, and thus further studies are in progress.

  16. Groundwater storage changes in arctic permafrost watersheds from GRACE and in situ measurements

    International Nuclear Information System (INIS)

    Muskett, Reginald R; Romanovsky, Vladimir E

    2009-01-01

    The Arctic permafrost regions make up the largest area component of the cryosphere. Observations from the Gravity Recovery and Climate Experiment (GRACE) mission offer to provide a greater understanding of changes in water mass within permafrost regions. We investigate a GRACE monthly time series, snow water equivalent from the special scanning microwave imager (SSM/I), vegetation water content and soil moisture from the advanced microwave scanning radiometer for the Earth observation system (AMSR-E) and in situ discharge of the Lena, Yenisei, Ob', and Mackenzie watersheds. The GRACE water equivalent mass change responded to mass loading by snow accumulation in winter and mass unloading by runoff in spring-summer. Comparison of secular trends from GRACE to runoff suggests groundwater storage increased in the Lena and Yenisei watersheds, decreased in the Mackenzie watershed, and was unchanged in the Ob' watershed. We hypothesize that the groundwater storage changes are linked to the development of closed- and open-talik in the continuous permafrost zone and the decrease of permafrost lateral extent in the discontinuous permafrost zone of the watersheds.

  17. Using an SLR inversion to measure the mass balance of Greenland before and during GRACE

    Science.gov (United States)

    Bonin, Jennifer

    2016-04-01

    The GRACE mission has done an admirable job of measuring large-scale mass changes over Greenland since its launch in 2002. However before that time, measurements of large-scale ice mass balance were few and far between, leading to a lack of baseline knowledge. High-quality Satellite Laser Ranging (SLR) data existed a decade earlier, but normally has too low a spatial resolution to be used for this purpose. I demonstrate that a least squares inversion technique can reconstitute the SLR data and use it to measure ice loss over Greenland. To do so, I first simulate the problem by degrading today's GRACE data to a level comparable with SLR, then demonstrating that the inversion can re-localize Greenland's contribution to the low-resolution signal, giving an accurate time series of mass change over all of Greenland which compares well with the full-resolution GRACE estimates. I then utilize that method on the actual SLR data, resulting in an independent 1994-2014 time series of mass change over Greenland. I find favorable agreement between the pure-SLR inverted results and the 2012 Ice-sheet Mass Balance Inter-comparison Exercise (IMBIE) results, which are largely based on the "input-output" modeling method before GRACE's launch.

  18. Augustin Erath's reconciliation of Thomist and Molinist Doctrines on Grace and Free Human Action

    Czech Academy of Sciences Publication Activity Database

    Dvořák, Petr

    2016-01-01

    Roč. 64, Suppl. (2016), s. 185-207 ISSN 0015-1831 R&D Projects: GA ČR GB14-37038G Institutional support: RVO:67985955 Keywords : free will * divine action * divine causation * grace Subject RIV: AA - Philosophy ; Religion

  19. Analysis of Seasonal Variability in Gulf of Alaska Glacier Mass Balance using GRACE

    Science.gov (United States)

    Arendt, A. A.; Luthcke, S. B.; Oneel, S.; Gardner, A. S.; Hill, D. F.

    2011-12-01

    Mass variations of glaciers in Alaska/northwestern Canada must be quantified in order to assess impacts on ecosystems, human infrastructure, and global sea level. Here we combine Gravity Recovery and Climate Experiment (GRACE) observations with a wide range of satellite and field data to investigate drivers of these recent changes, with a focus on seasonal variations. Our central focus will be the exceptionally high mass losses of 2009, which do not correlate with weather station temperature and precipitation data, but may be linked to ash fall from the March 31, 2009 eruption of Mt. Redoubt. The eruption resulted in a significant decrease in MODIS-derived surface albedo over many Alaska glacier regions, and likely contributed to some of the 2009 anomalous mass loss observed by GRACE. We also focus on the Juneau and Stikine Icefield regions that are far from the volcanic eruption but experienced the largest mass losses of any region in 2009. Although rapid drawdown of tidewater glaciers was occurring in southeast Alaska during 2009, we show these changes were probably not sufficiently widespread to explain all of the GRACE signal in those regions. We examine additional field and satellite datasets to quantify potential errors in the climate and GRACE fields that could result in the observed discrepancy.

  20. Satellite altimetry and GRACE gravimetry for studies of annual water storage variations in Bangladesh

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Berry, P.; Freeman, J.

    2008-01-01

    Four different data sources have been compared with respect to observations of the annual water storage variations in the region of Bangladesh. Data from satellite altimeters and river gauges estimates the variation in surface water storage in the major rivers of Bangladesh. The GRACE satellites ...

  1. Flight-Like Optical Reference Cavity for GRACE Follow-On Laser Frequency Stabilization

    Science.gov (United States)

    Folkner, W. M.; deVine, G.; Klipstein, W. M.; McKenzie, K.; Spero, R.; Thompson, R.; Yu, N.; Stephens, M.; Leitch, J.; Pierce, R.; hide

    2011-01-01

    We describe a prototype optical cavity and associated optics that has been developed to provide a stable frequency reference for a future space-based laser ranging system. This instrument is being considered for inclusion as a technology demonstration on the recently announced GRACE follow-on mission, which will monitor variations in the Earth's gravity field.

  2. Evaluation of recent GRACE monthly solution series with an ice sheet perspective

    Science.gov (United States)

    Horwath, Martin; Groh, Andreas

    2016-04-01

    GRACE monthly global gravity field solutions have undergone a remarkable evolution, leading to the latest (Release 5) series by CSR, GFZ, and JPL, to new series by other processing centers, such as ITSG and AIUB, as well as to efforts to derive combined solutions, particularly by the EGSIEM (European Gravity Service for Improved Emergency Management) project. For applications, such as GRACE inferences on ice sheet mass balance, the obvious question is on what GRACE solution series to base the assessment. Here we evaluate different GRACE solution series (including the ones listed above) in a unified framework. We concentrate on solutions expanded up to degree 90 or higher, since this is most appropriate for polar applications. We empirically assess the error levels in the spectral as well as in the spatial domain based on the month-to-month scatter in the high spherical harmonic degrees. We include empirical assessment of error correlations. We then apply all series to infer Antarctic and Greenland mass change time series and compare the results in terms of apparent signal content and noise level. We find that the ITSG solutions show lowest noise level in the high degrees (above 60). A preliminary combined solution from the EGSIEM project shows lowest noise in the degrees below 60. This virtue maps into the derived ice mass time series, where the EGSIEM-based results show the lowest noise in most cases. Meanwhile, there is no indication that any of the considered series systematically dampens actual geophysical signals.

  3. GRACE Hydrological estimates for small basins: Evaluating processing approaches on the High Plains Aquifer, USA

    Science.gov (United States)

    Longuevergne, Laurent; Scanlon, Bridget R.; Wilson, Clark R.

    2010-11-01

    The Gravity Recovery and Climate Experiment (GRACE) satellites provide observations of water storage variation at regional scales. However, when focusing on a region of interest, limited spatial resolution and noise contamination can cause estimation bias and spatial leakage, problems that are exacerbated as the region of interest approaches the GRACE resolution limit of a few hundred km. Reliable estimates of water storage variations in small basins require compromises between competing needs for noise suppression and spatial resolution. The objective of this study was to quantitatively investigate processing methods and their impacts on bias, leakage, GRACE noise reduction, and estimated total error, allowing solution of the trade-offs. Among the methods tested is a recently developed concentration algorithm called spatiospectral localization, which optimizes the basin shape description, taking into account limited spatial resolution. This method is particularly suited to retrieval of basin-scale water storage variations and is effective for small basins. To increase confidence in derived methods, water storage variations were calculated for both CSR (Center for Space Research) and GRGS (Groupe de Recherche de Géodésie Spatiale) GRACE products, which employ different processing strategies. The processing techniques were tested on the intensively monitored High Plains Aquifer (450,000 km2 area), where application of the appropriate optimal processing method allowed retrieval of water storage variations over a portion of the aquifer as small as ˜200,000 km2.

  4. Selecting Candidates for Key Leadership Positions in Program Executive Offices Ground Combat Systems and Combat Service and Combat Service Support

    Science.gov (United States)

    2016-10-14

    start or continue a profitable growth pattern and boost morale and motivation, a poor decision may bring the company to the brink of financial...HON Frank Kendall issued a memorandum titled “Key Leadership Positions and Qualification Criteria” (Kendall, 2013). This memorandum provides a...Chief Developmental Tester • Program Lead, Business Financial Manager SELECTING CANDIDATES FOR KEY LEADERSHIP POSITIONS 4

  5. Breaking Ground: Analysis of the Assessment System and Impact of Mexico's Teacher Incentive Program "Carrera Magisterial." Technical Report

    Science.gov (United States)

    Santibanez, Lucrecia; Martinez, Jose Felipe; Datar, Ashlesha; McEwan, Patrick J.; Setodji, Claude Messan; Basurto-Davila, Ricardo

    2007-01-01

    Mexico's Carrera Magisterial (CM) is one of the pioneer teacher incentive programs in the world. It was instituted in 1992 and designed jointly by the federal education authorities, state authorities, and the teachers' union as a horizontal promotion system that rewards teachers with salary bonuses on the basis of their performance. Teacher…

  6. The Use of Grounded Theory to Develop a Framework for Understanding Student Retention in Community College Nursing Programs

    Science.gov (United States)

    Priode, Kimberly S.

    2013-01-01

    Gaining admission into pre-licensure nursing programs has proven to be quite difficult for the average college student. Topping the list of crucial priorities for many academic institutions is the retention of these nursing students. Yet, the reality is that many students decide not to complete their course of study for reasons other than academic…

  7. Quantifying Modern Recharge to the Nubian Sandstone Aquifer System: Inferences from GRACE and Land Surface Models

    Science.gov (United States)

    Mohamed, A.; Sultan, M.; Ahmed, M.; Yan, E.

    2014-12-01

    The Nubian Sandstone Aquifer System (NSAS) is shared by Egypt, Libya, Chad and Sudanand is one of the largest (area: ~ 2 × 106 km2) groundwater systems in the world. Despite its importance to the population of these countries, major hydrological parameters such as modern recharge and extraction rates remain poorly investigated given: (1) the large extent of the NSAS, (2) the absence of comprehensive monitoring networks, (3) the general inaccessibility of many of the NSAS regions, (4) difficulties in collecting background information, largely included in unpublished governmental reports, and (5) limited local funding to support the construction of monitoring networks and/or collection of field and background datasets. Data from monthly Gravity Recovery and Climate Experiment (GRACE) gravity solutions were processed (Gaussian smoothed: 100 km; rescaled) and used to quantify the modern recharge to the NSAS during the period from January 2003 to December 2012. To isolate the groundwater component in GRACE data, the soil moisture and river channel storages were removed using the outputs from the most recent Community Land Model version 4.5 (CLM4.5). GRACE-derived recharge calculations were performed over the southern NSAS outcrops (area: 835 × 103 km2) in Sudan and Chad that receive average annual precipitation of 65 km3 (77.5 mm). GRACE-derived recharge rates were estimated at 2.79 ± 0.98 km3/yr (3.34 ± 1.17 mm/yr). If we take into account the total annual extraction rates (~ 0.4 km3; CEDARE, 2002) from Chad and Sudan the average annual recharge rate for the NSAS could reach up to ~ 3.20 ± 1.18 km3/yr (3.84 ± 1.42 mm/yr). Our recharge rates estimates are similar to those calculated using (1) groundwater flow modelling in the Central Sudan Rift Basins (4-8 mm/yr; Abdalla, 2008), (2) WaterGAP global scale groundwater recharge model (plans are underway for the deployment of a GRACE follow-On and GRACE-II missions, we suggest that within the next few years, GRACE

  8. Sediment-Mass Accumulation Rate and Variability in the East China Sea Detected by GRACE

    Directory of Open Access Journals (Sweden)

    Ya-Chi Liu

    2016-09-01

    Full Text Available The East China Sea (ECS is a region with shallow continental shelves and a mixed oceanic circulation system allowing sediments to deposit on its inner shelf, particularly near the estuary of the Yangtze River. The seasonal northward-flowing Taiwan Warm Current and southward-flowing China Coastal Current trap sediments from the Yangtze River, which are accumulated over time at rates of up to a few mm/year in equivalent water height. Here, we use the Gravity Recovery and Climate Experiment (GRACE gravity products from three data centres to determine sediment mass accumulation rates (MARs and variability on the ECS inner shelf. We restore the atmospheric and oceanic effects to avoid model contaminations on gravity signals associated with sediment masses. We apply destriping and spatial filters to improve the gravity signals from GRACE and use the Global Land Data Assimilation System to reduce land leakage. The GRACE-derived MARs over April 2002–March 2015 on the ECS inner shelf are about 6 mm/year and have magnitudes and spatial patterns consistent with those from sediment-core measurements. The GRACE-derived monthly sediment depositions show variations at time scales ranging from six months to more than two years. Typically, a positive mass balance of sediment deposition occurs in late fall to early winter when the southward coastal currents prevail. A negative mass balance happens in summer when the coastal currents are northward. We identify quasi-biennial sediment variations, which are likely to be caused by quasi-biennial variations in rain and erosion in the Yangtze River basin. We briefly explain the mechanisms of such frequency-dependent variations in the GRACE-derived ECS sediment deposition. There is no clear perturbation on sediment deposition over the ECS inner shelf induced by the Three Gorges Dam. The limitations of GRACE in resolving sediment deposition are its low spatial resolution (about 250 km and possible contaminations by

  9. GRACE L1b inversion through a self-consistent modified radial basis function approach

    Science.gov (United States)

    Yang, Fan; Kusche, Juergen; Rietbroek, Roelof; Eicker, Annette

    2016-04-01

    Implementing a regional geopotential representation such as mascons or, more general, RBFs (radial basis functions) has been widely accepted as an efficient and flexible approach to recover the gravity field from GRACE (Gravity Recovery and Climate Experiment), especially at higher latitude region like Greenland. This is since RBFs allow for regionally specific regularizations over areas which have sufficient and dense GRACE observations. Although existing RBF solutions show a better resolution than classical spherical harmonic solutions, the applied regularizations cause spatial leakage which should be carefully dealt with. It has been shown that leakage is a main error source which leads to an evident underestimation of yearly trend of ice-melting over Greenland. Unlike some popular post-processing techniques to mitigate leakage signals, this study, for the first time, attempts to reduce the leakage directly in the GRACE L1b inversion by constructing an innovative modified (MRBF) basis in place of the standard RBFs to retrieve a more realistic temporal gravity signal along the coastline. Our point of departure is that the surface mass loading associated with standard RBF is smooth but disregards physical consistency between continental mass and passive ocean response. In this contribution, based on earlier work by Clarke et al.(2007), a physically self-consistent MRBF representation is constructed from standard RBFs, with the help of the sea level equation: for a given standard RBF basis, the corresponding MRBF basis is first obtained by keeping the surface load over the continent unchanged, but imposing global mass conservation and equilibrium response of the oceans. Then, the updated set of MRBFs as well as standard RBFs are individually employed as the basis function to determine the temporal gravity field from GRACE L1b data. In this way, in the MRBF GRACE solution, the passive (e.g. ice melting and land hydrology response) sea level is automatically

  10. Insights about data assimilation frameworks for integrating GRACE with hydrological models

    Science.gov (United States)

    Schumacher, Maike; Kusche, Jürgen; Van Dijk, Albert I. J. M.; Döll, Petra; Schuh, Wolf-Dieter

    2016-04-01

    Improving the understanding of changes in the water cycle represents a challenging objective that requires merging information from various disciplines. Debates exist on selecting an appropriate assimilation technique to integrate GRACE-derived terrestrial water storage changes (TWSC) into hydrological models in order to downscale and disaggregate GRACE TWSC, overcome model limitations, and improve monitoring and forecast skills. Yet, the effect of the specific data assimilation technique in conjunction with ill-conditioning, colored noise, resolution mismatch between GRACE and model, and other complications is still unclear. Due to its simplicity, ensemble Kalman filters or smoothers (EnKF/S) are often applied. In this study, we show that modification of the filter approach might open new avenues to improve the integration process. Particularly, we discuss an improved calibration and data assimilation (C/DA) framework (Schumacher et al., 2016), which is based on the EnKF and was extended by the square root analysis scheme (SQRA) and the singular evolutive interpolated Kalman (SEIK) filter. In addition, we discuss an off-line data blending approach (Van Dijk et al., 2014) that offers the chance to merge multi-model ensembles with GRACE observations. The investigations include: (i) a theoretical comparison, focusing on similarities and differences of the conceptual formulation of the filter algorithms, (ii) a practical comparison, for which the approaches were applied to an ensemble of runs of the WaterGAP Global Hydrology Model (WGHM), as well as (iii) an impact assessment of the GRACE error structure on C/DA results. First, a synthetic experiment over the Mississippi River Basin (USA) was used to gain insights about the C/DA set-up before applying it to real data. The results indicated promising performances when considering alternative methods, e.g. applying the SEIK algorithm improved the correlation coefficient and root mean square error (RMSE) of TWSC by 0

  11. Long Range River Discharge Forecasting Using the Gravity Recovery and Climate Experiment (GRACE) Satellite to Predict Conditions for Endemic Cholera

    Science.gov (United States)

    Jutla, A.; Akanda, A. S.; Colwell, R. R.

    2014-12-01

    Prediction of conditions of an impending disease outbreak remains a challenge but is achievable if the associated and appropriate large scale hydroclimatic process can be estimated in advance. Outbreaks of diarrheal diseases such as cholera, are related to episodic seasonal variability in river discharge in the regions where water and sanitation infrastructure are inadequate and insufficient. However, forecasting river discharge, few months in advance, remains elusive where cholera outbreaks are frequent, probably due to non-availability of geophysical data as well as transboundary water stresses. Here, we show that satellite derived water storage from Gravity Recovery and Climate Experiment Forecasting (GRACE) sensors can provide reliable estimates on river discharge atleast two months in advance over regional scales. Bayesian regression models predicted flooding and drought conditions, a prerequisite for cholera outbreaks, in Bengal Delta with an overall accuracy of 70% for upto 60 days in advance without using any other ancillary ground based data. Forecasting of river discharge will have significant impacts on planning and designing intervention strategies for potential cholera outbreaks in the coastal regions where the disease remain endemic and often fatal.

  12. Does C-reactive Protein Add Prognostic Value to GRACE Score in Acute Coronary Syndromes?

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Luis Cláudio Lemos, E-mail: lccorreia@terra.com.br; Vasconcelos, Isis; Garcia, Guilherme; Kalil, Felipe; Ferreira, Felipe; Silva, André; Oliveira, Ruan; Carvalhal, Manuela; Freitas, Caio; Noya-Rabelo, Márcia Maria [Escola Bahiana de Medicina e Saúde Pública, Salvador, BA (Brazil); Hospital São Rafael, Salvador, BA (Brazil)

    2014-05-15

    The incremental prognostic value of plasma levels of C-reactive protein (CRP) in relation to GRACE score has not been established in patients with acute coronary syndrome (ACS) with non-ST segment elevation. To test the hypothesis that CRP measurements at admission increases the prognostic value of GRACE score in patients with ACS. A total of 290 subjects, consecutively admitted for ACS, with plasma material obtained upon admission CRP measurement using a high-sensitivity method (nephelometry) were studied. Cardiovascular outcomes during hospitalization were defined by the combination of death, nonfatal myocardial infarction or nonfatal refractory angina. The incidence of cardiovascular events during hospitalization was 15% (18 deaths, 11 myocardial infarctions, 13 angina episodes) with CRP showing C-statistics of 0.60 (95% CI = 0.51-0.70, p = 0.034) in predicting these outcomes. After adjustment for the GRACE score, elevated CRP (defined as the best cutoff point) tended to be associated with hospital events (OR = 1.89, 95% CI = 0.92 to 3.88, p = 0.08). However, the addition of the variable elevated CRP in the GRACE model did not result in significant increase in C-statistics, which ranged from 0.705 to 0.718 (p = 0.46). Similarly, there was no significant reclassification of risk with the addition of CRP in the predictor model (net reclassification = 5.7 %, p = 0.15). Although CRP is associated with hospital outcomes, this inflammatory marker does not increase the prognostic value of the GRACE score.

  13. Can we observe the fronts of the Antarctic Circumpolar Current using GRACE OBP?

    Science.gov (United States)

    Makowski, J.; Chambers, D. P.; Bonin, J. A.

    2014-12-01

    The Antarctic Circumpolar Current (ACC) and the Southern Ocean remains one of the most undersampled regions of the world's oceans. The ACC is comprised of four major fronts: the Sub-Tropical Front (STF), the Polar Front (PF), the Sub-Antarctic Front (SAF), and the Southern ACC Front (SACCF). These were initially observed individually from repeat hydrographic sections and their approximate locations globally have been quantified using all available temperature data from the World Ocean and Climate Experiment (WOCE). More recent studies based on satellite altimetry have found that the front positions are more dynamic and have shifted south by up to 1° on average since 1993. Using ocean bottom pressure (OBP) data from the current Gravity Recovery and Climate Experiment (GRACE) we have measured integrated transport variability of the ACC south of Australia. However, differentiation of variability of specific fronts has been impossible due to the necessary smoothing required to reduce noise and correlated errors in the measurements. The future GRACE Follow-on (GFO) mission and the post 2020 GRACE-II mission are expected to produce higher resolution gravity fields with a monthly temporal resolution. Here, we study the resolution and error characteristics of GRACE gravity data that would be required to resolve variations in the front locations and transport. To do this, we utilize output from a high-resolution model of the Southern Ocean, hydrology models, and ice sheet surface mass balance models; add various amounts of random and correlated errors that may be expected from GFO and GRACE-II; and quantify requirements needed for future satellite gravity missions to resolve variations along the ACC fronts.

  14. Groundwater Withdrawals under Drought: Reconciling GRACE and Models in the United States High Plains Aquifer

    Science.gov (United States)

    Nie, W.; Zaitchik, B. F.; Kumar, S.; Rodell, M.

    2017-12-01

    Advanced Land Surface Models (LSM) offer a powerful tool for studying and monitoring hydrological variability. Highly managed systems, however, present a challenge for these models, which typically have simplified or incomplete representations of human water use, if the process is represented at all. GRACE, meanwhile, detects the total change in water storage, including change due to human activities, but does not resolve the source of these changes. Here we examine recent groundwater declines in the US High Plains Aquifer (HPA), a region that is heavily utilized for irrigation and that is also affected by episodic drought. To understand observed decline in groundwater (well observation) and terrestrial water storage (GRACE) during a recent multi-year drought, we modify the Noah-MP LSM to include a groundwater pumping irrigation scheme. To account for seasonal and interannual variability in active irrigated area we apply a monthly time-varying greenness vegetation fraction (GVF) dataset to the model. A set of five experiments were performed to study the impact of irrigation with groundwater withdrawal on the simulated hydrological cycle of the HPA and to assess the importance of time-varying GVF when simulating drought conditions. The results show that including the groundwater pumping irrigation scheme in Noah-MP improves model agreement with GRACE mascon solutions for TWS and well observations of groundwater anomaly in the southern HPA, including Texas and Kansas, and that accounting for time-varying GVF is important for model realism under drought. Results for the HPA in Nebraska are mixed, likely due to misrepresentation of the recharge process. This presentation will highlight the value of the GRACE constraint for model development, present estimates of the relative contribution of climate variability and irrigation to declining TWS in the HPA under drought, and identify opportunities to integrate GRACE-FO with models for water resource monitoring in heavily

  15. Does C-reactive Protein Add Prognostic Value to GRACE Score in Acute Coronary Syndromes?

    International Nuclear Information System (INIS)

    Correia, Luis Cláudio Lemos; Vasconcelos, Isis; Garcia, Guilherme; Kalil, Felipe; Ferreira, Felipe; Silva, André; Oliveira, Ruan; Carvalhal, Manuela; Freitas, Caio; Noya-Rabelo, Márcia Maria

    2014-01-01

    The incremental prognostic value of plasma levels of C-reactive protein (CRP) in relation to GRACE score has not been established in patients with acute coronary syndrome (ACS) with non-ST segment elevation. To test the hypothesis that CRP measurements at admission increases the prognostic value of GRACE score in patients with ACS. A total of 290 subjects, consecutively admitted for ACS, with plasma material obtained upon admission CRP measurement using a high-sensitivity method (nephelometry) were studied. Cardiovascular outcomes during hospitalization were defined by the combination of death, nonfatal myocardial infarction or nonfatal refractory angina. The incidence of cardiovascular events during hospitalization was 15% (18 deaths, 11 myocardial infarctions, 13 angina episodes) with CRP showing C-statistics of 0.60 (95% CI = 0.51-0.70, p = 0.034) in predicting these outcomes. After adjustment for the GRACE score, elevated CRP (defined as the best cutoff point) tended to be associated with hospital events (OR = 1.89, 95% CI = 0.92 to 3.88, p = 0.08). However, the addition of the variable elevated CRP in the GRACE model did not result in significant increase in C-statistics, which ranged from 0.705 to 0.718 (p = 0.46). Similarly, there was no significant reclassification of risk with the addition of CRP in the predictor model (net reclassification = 5.7 %, p = 0.15). Although CRP is associated with hospital outcomes, this inflammatory marker does not increase the prognostic value of the GRACE score

  16. Using GRACE Satellite Gravimetry for Assessing Large-Scale Hydrologic Extremes

    Directory of Open Access Journals (Sweden)

    Alexander Y. Sun

    2017-12-01

    Full Text Available Global assessment of the spatiotemporal variability in terrestrial total water storage anomalies (TWSA in response to hydrologic extremes is critical for water resources management. Using TWSA derived from the gravity recovery and climate experiment (GRACE satellites, this study systematically assessed the skill of the TWSA-climatology (TC approach and breakpoint (BP detection method for identifying large-scale hydrologic extremes. The TC approach calculates standardized anomalies by using the mean and standard deviation of the GRACE TWSA corresponding to each month. In the BP detection method, the empirical mode decomposition (EMD is first applied to identify the mean return period of TWSA extremes, and then a statistical procedure is used to identify the actual occurrence times of abrupt changes (i.e., BPs in TWSA. Both detection methods were demonstrated on basin-averaged TWSA time series for the world’s 35 largest river basins. A nonlinear event coincidence analysis measure was applied to cross-examine abrupt changes detected by these methods with those detected by the Standardized Precipitation Index (SPI. Results show that our EMD-assisted BP procedure is a promising tool for identifying hydrologic extremes using GRACE TWSA data. Abrupt changes detected by the BP method coincide well with those of the SPI anomalies and with documented hydrologic extreme events. Event timings obtained by the TC method were ambiguous for a number of river basins studied, probably because the GRACE data length is too short to derive long-term climatology at this time. The BP approach demonstrates a robust wet-dry anomaly detection capability, which will be important for applications with the upcoming GRACE Follow-On mission.

  17. Combining GRACE and Altimetry to solve for present day mass changes and GIA

    Science.gov (United States)

    Rietbroek, R.; Lück, C.; Uebbing, B.; Kusche, J.; King, M. A.

    2017-12-01

    Past and present day sea level rise is closely linked to geoid and surface deformation changes from the ongoing glacial isostatic adjustment (GIA). Sea level, as detected by radar altimetry, senses the radial deformation of the ocean floor as mantle material slowly flows back to the locations of the former glacial domes. This manifests itself as a net subsidence when averaged over the entire ocean, but can regionally be seen as an uplift for locations close to the former ice sheets. Furthermore, mass driven sea level as derived from GRACE, is even more sensitive to GIA induced mass redistribution in the solid Earth. Consequently, errors in GIA corrections, most notably errors in mantle viscosity and ice histories, have a different leverage on regional sea level estimates from GRACE and altimetry. In this study, we discuss the abilities of a GRACE-altimetry combination to co-estimate GIA corrections together with present day contributors to sea level, rather than simply prescribing a GIA correction from a model. The data is combined in a joint inversion scheme which makes use of spatial patterns to parameterize present day loading effects and GIA. We show that the GRACE-altimetry combination requires constraints, but generally steers the Antarctic GIA signal towards a weaker present day signal in Antarctica compared to a ICE5-G(VM2) derived model. Furthermore, in light of the aging GRACE mission, we show sensitivity studies of how well one could estimate GIA corrections when using other low earth orbiters such as SWARM or CHAMP. Finally, we show whether the Antarctic GNSS station network may be useful in separating GIA from present day mass signals in this type of inversion schemes.

  18. Comparison of GPS and GRACE hydrological loading signatures in Myanmar, India, Bangladesh, and Bhutan

    Science.gov (United States)

    Materna, K.; Feng, L.; Lindsey, E. O.; Hill, E.; Burgmann, R.

    2017-12-01

    The elastic response of the lithosphere to surface mass redistributions produces significant deformation that can be observed in geodetic time series. This deformation is especially pronounced in Southeast Asia, where the annual monsoon produces large-amplitude hydrological loads. The MIBB network of 20 continuous GPS stations in Myanmar, India, Bangladesh, and Bhutan, operational since 2012, provides an opportunity to study the earth's response to these loads. In this study, we use GRACE gravity products as an estimate of surface water distribution, and input these estimates into an elastic loading calculation. We compare the predicted deformation with that observed with GPS. We find that elastic loading from the GRACE gravity field is able to explain the phase and the peak-to-peak amplitude (typically 2-3 cm) of the vertical GPS oscillations in northeast India and central Myanmar. GRACE-based corrections reduce the RMS scatter of the GPS data by 30%-45% in these regions. However, this approach does not capture all of the variation in central Bangladesh and southern Myanmar. Local hydrological effects, non-tidal ocean loads, poroelastic deformation, or differences in elastic properties may explain discrepancies between the GPS and GRACE signals in these places. The results of our calculations have practical implications for campaign GPS measurements in Myanmar, which make up the majority of geodetic measurements at this point. We may be able to reduce errors in campaign measurements and increase the accuracy of velocity estimates by correcting for hydrologic signals with GRACE data. The results also have potential implications for crustal rheology in Southeast Asia.

  19. Monitoring groundwater storage changes in the highly dynamic Bengal Basin: validation of GRACE measurements

    Science.gov (United States)

    Shamsudduha, M.; Taylor, R. G.; Longuevergne, L.

    2011-12-01

    Monitoring of spatio-temporal changes in terrestrial water storage (ΔTWS) provides valuable information regarding the basin-scale dynamics of hydrological systems. Recent satellite measurements of the ΔTWS under the Gravity Recovery and Climate Experiment (GRACE) enable the derivation of groundwater storage changes (ΔGWS) where in situ data are limited. In the well monitored and highly-dynamic Bengal Basin of Bangladesh, we test the ability of GRACE measurements to trace the seasonality and trend in groundwater storage associated with intensive groundwater abstraction for dry-season irrigation and wet-season (monsoonal) recharge. Two different GRACE products (CSR and GRGS) and data processing methods (gridded and spherical harmonics) are also compared. Results show that GRACE derived estimates of recent (2003 to 2007) ΔGWS correlate well (r=0.77 to 0.93, p-value CSR for these estimates. ΔGWS accounts for 44% of the total variation in ΔTWS in the Bengal Basin. Changes in surface water storage (ΔSWS) estimated from a network of 298 river gauging stations and soil moisture storage (ΔSMS) derived from Land Surface Models explain 22% and 33% of ΔTWS respectively. Groundwater depletion estimated from borehole hydrographs (-0.52±0.30 km3/yr) is within the range of satellite-derived estimates (-0.44 to -2.04 km3/yr) that result from uncertainty associated with ΔSMS (CLM, NOAH, VIC) and GRACE data processing techniques. Recent (2003 to 2007) estimates of groundwater depletion are substantially greater than the long-term (1985 to 2007) mean (-0.21±0.03 km3/yr) and are explained primarily by substantial increases in groundwater abstraction for the dry-season irrigation and drinking water supplies over the last two decades.

  20. Constraining Earth's Rheology of the Barents Sea Using Grace Gravity Change Observations

    Science.gov (United States)

    van der Wal, W.; Root, B. C.; Tarasov, L.

    2014-12-01

    The Barents Sea region was ice covered during last glacial maximum and experiences Glacial Isostatic Adjustment (GIA). Because of the limited amount of relevant geological and geodetic observations, it is difficult to constrain GIA models for this region. With improved ice sheet models and gravity observations from GRACE, it is possible to better constrain Earth rheology. This study aims to constrain the upper mantle viscosity and elastic lithosphere thickness from GRACE data in the Barents Sea region. The GRACE observations are corrected for current ice melting on Svalbard, Novaya Zemlya and Frans Joseph Land. A secular trend in gravity rate trend is estimated from the CSR release 5 GRACE data for the period of February 2003 to July 2013. Furthermore, long wavelength effects from distant large mass balance signals such as Greenland ice melting are filtered out. A new high-variance set of ice loading histories from calibrated glaciological modeling are used in the GIA modeling as it is found that ICE-5G over-estimates the observed GIA gravity change in the region. It is found that the rheology structure represented by VM5a results in over-estimation of the observed gravity change in the region for all ice sheet chronologies investigated. Therefore, other rheological Earth models were investigated. The best fitting upper mantle viscosity and elastic lithosphere thickness in the Barents Sea region are 4 (±0.5)*10^20 Pas and 110 (±20) km, respectively. The GRACE satellite mission proves to be a useful constraint in the Barents Sea Region for improving our knowledge on the upper mantle rheology.

  1. Phase Error Modeling and Its Impact on Precise Orbit Determination of GRACE Satellites

    Directory of Open Access Journals (Sweden)

    Jia Tu

    2012-01-01

    Full Text Available Limiting factors for the precise orbit determination (POD of low-earth orbit (LEO satellite using dual-frequency GPS are nowadays mainly encountered with the in-flight phase error modeling. The phase error is modeled as a systematic and a random component each depending on the direction of GPS signal reception. The systematic part and standard deviation of random part in phase error model are, respectively, estimated by bin-wise mean and standard deviation values of phase postfit residuals computed by orbit determination. By removing the systematic component and adjusting the weight of phase observation data according to standard deviation of random component, the orbit can be further improved by POD approach. The GRACE data of 1–31 January 2006 are processed, and three types of orbit solutions, POD without phase error model correction, POD with mean value correction of phase error model, and POD with phase error model correction, are obtained. The three-dimensional (3D orbit improvements derived from phase error model correction are 0.0153 m for GRACE A and 0.0131 m for GRACE B, and the 3D influences arisen from random part of phase error model are 0.0068 m and 0.0075 m for GRACE A and GRACE B, respectively. Thus the random part of phase error model cannot be neglected for POD. It is also demonstrated by phase postfit residual analysis, orbit comparison with JPL precise science orbit, and orbit validation with KBR data that the results derived from POD with phase error model correction are better than another two types of orbit solutions generated in this paper.

  2. Mass Evolution of Mediterranean, Black, Red, and Caspian Seas from GRACE and Altimetry: Accuracy Assessment and Solution Calibration

    Science.gov (United States)

    Loomis, B. D.; Luthcke, S. B.

    2016-01-01

    We present new measurements of mass evolution for the Mediterranean, Black, Red, and Caspian Seas as determined by the NASA Goddard Space Flight Center (GSFC) GRACE time-variable global gravity mascon solutions. These new solutions are compared to sea surface altimetry measurements of sea level anomalies with steric corrections applied. To assess their accuracy, the GRACE and altimetry-derived solutions are applied to the set of forward models used by GSFC for processing the GRACE Level-1B datasets, with the resulting inter-satellite range acceleration residuals providing a useful metric for analyzing solution quality.

  3. Ground-Water Quality Data in the Upper Santa Ana Watershed Study Unit, November 2006-March 2007: Results from the California GAMA Program

    Science.gov (United States)

    Kent, Robert; Belitz, Kenneth

    2009-01-01

    Ground-water quality in the approximately 1,000-square-mile Upper Santa Ana Watershed study unit (USAW) was investigated from November 2006 through March 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Upper Santa Ana Watershed study was designed to provide a spatially unbiased assessment of raw ground-water quality within USAW, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 99 wells in Riverside and San Bernardino Counties. Ninety of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells). Nine wells were selected to provide additional understanding of specific water-quality issues identified within the basin (understanding wells). The ground-water samples were analyzed for a large number of organic constituents (volatile organic compounds [VOCs], pesticides and pesticide degradates, pharmaceutical compounds, and potential wastewater-indicator compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], 1,4-dioxane, and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water) and dissolved noble gases also were measured to help identify sources and ages of the sampled ground water. Dissolved gases, and isotopes of nitrogen gas and of dissolved nitrate also were measured in order to investigate the sources and occurrence of

  4. GRACE-Based Analysis of Total Water Storage Trends and Groundwater Fluctuations in the North-Western Sahara Aquifer System (NWSAS) and Tindouf Aquifer in Northwest Africa

    Science.gov (United States)

    Lezzaik, K. A.; Milewski, A.

    2013-12-01

    Optimal water management practices and strategies, in arid and semi-arid environments, are often hindered by a lack of quantitative and qualitative understanding of hydrological processes. Moreover, progressive overexploitation of groundwater resources to meet agricultural, industrial, and domestic requirements is drawing concern over the sustainability of such exhaustive abstraction levels, especially in environments where groundwater is a major source of water. NASA's GRACE (gravity recovery and climate change experiment) mission, since March 2002, has advanced the understanding of hydrological events, especially groundwater depletion, through integrated measurements and modeling of terrestrial water mass. In this study, GLDAS variables (rainfall rate, evapotranspiration rate, average soil moisture), and TRMM 3B42.V7A precipitation satellite data, were used in combination with 95 GRACE-generated gravitational anomalies maps, to quantify total water storage change (TWSC) and groundwater storage change (GWSC) from January 2003 to December 2010 (excluding June 2003), in the North-Western Sahara Aquifer System (NWSAS) and Tindouf Aquifer System in northwestern Africa. Separately processed and computed GRACE products by JPL (Jet Propulsion Laboratory, NASA), CSR (Center of Space Research, UT Austin), and GFZ (German Research Centre for Geoscience, Potsdam), were used to determine which GRACE dataset(s) best reflect total water storage and ground water changes in northwest Africa. First-order estimates of annual TWSC for NWSAS (JPL: +5.297 BCM; CSR: -5.33 BCM; GFZ: -9.96 BCM) and Tindouf Aquifer System (JPL: +1.217 BCM; CSR: +0.203 BCM; GFZ: +1.019 BCM), were computed using zonal averaging over a span of eight years. Preliminary findings of annual GWSC for NWSAS (JPL: +2.45 BCM; CSR: -2.278 BCM; GFZ: -6.913 BCM) and Tindouf Aquifer System (JPL: +1.108 BCM; CSR: +0.094 BCM; GFZ: +0.910 BCM), were calculating using a water budget approach, parameterized by GLDAS

  5. Finite-element three-dimensional ground-water (FE3DGW) flow model - formulation, program listings and users' manual

    International Nuclear Information System (INIS)

    Gupta, S.K.; Cole, C.R.; Bond, F.W.

    1979-12-01

    The Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program is developing and applying the methodology for assessing the far-field, long-term post-closure safety of deep geologic nuclear waste repositories. AEGIS is being performed by Pacific Northwest Laboratory (PNL) under contract with the Office of Nuclear Waste Isolation (OWNI) for the Department of Energy (DOE). One task within AEGIS is the development of methodology for analysis of the consequences (water pathway) from loss of repository containment as defined by various release scenarios. Analysis of the long-term, far-field consequences of release scenarios requires the application of numerical codes which simulate the hydrologic systems, model the transport of released radionuclides through the hydrologic systems to the biosphere, and, where applicable, assess the radiological dose to humans. Hydrologic and transport models are available at several levels of complexity or sophistication. Model selection and use are determined by the quantity and quality of input data. Model development under AEGIS and related programs provides three levels of hydrologic models, two levels of transport models, and one level of dose models (with several separate models). This document consists of the description of the FE3DGW (Finite Element, Three-Dimensional Groundwater) Hydrologic model third level (high complexity) three-dimensional, finite element approach (Galerkin formulation) for saturated groundwater flow

  6. Amazing grace: Vancouver's supervised injection facility granted six-month lease on life

    Directory of Open Access Journals (Sweden)

    Small Dan

    2008-01-01

    the light of the scientific evidence, and lead the way towards to provision of a permanent medical exemption for injection facilities from Canada's Controlled Drugs and Substances Act (CDSA. In so doing, the Prime Minister would be on the brink of grace and would rescue a life saving health program from perpetual political interference.

  7. Non-Linear Non Stationary Analysis of Two-Dimensional Time-Series Applied to GRACE Data, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovative two-dimensional (2D) empirical mode decomposition (EMD) analysis was applied to NASA's Gravity Recovery and Climate Experiment (GRACE)...

  8. Evaluating Greenland glacial isostatic adjustment corrections using GRACE, altimetry and surface mass balance data

    International Nuclear Information System (INIS)

    Sutterley, Tyler C; Velicogna, Isabella; Csatho, Beata; Rezvan-Behbahani, Soroush; Babonis, Greg; Van den Broeke, Michiel

    2014-01-01

    Glacial isostatic adjustment (GIA) represents a source of uncertainty for ice sheet mass balance estimates from the Gravity Recovery and Climate Experiment (GRACE) time-variable gravity measurements. We evaluate Greenland GIA corrections from Simpson et al (2009 Quat. Sci. Rev. 28 1631–57), A et al (2013 Geophys. J. Int. 192 557–72) and Wu et al (2010 Nature Geosci. 3 642–6) by comparing the spatial patterns of GRACE-derived ice mass trends calculated using the three corrections with volume changes from ICESat (Ice, Cloud, and land Elevation Satellite) and OIB (Operation IceBridge) altimetry missions, and surface mass balance products from the Regional Atmospheric Climate Model (RACMO). During the period September 2003–August 2011, GRACE ice mass changes obtained using the Simpson et al (2009 Quat. Sci. Rev. 28 1631–57) and A et al (2013 Geophys. J. Int. 192 557–72) GIA corrections yield similar spatial patterns and amplitudes, and are consistent with altimetry observations and surface mass balance data. The two GRACE estimates agree within 2% on average over the entire ice sheet, and better than 15% in four subdivisions of Greenland. The third GRACE estimate corrected using the (Wu et al 2010 Nature Geosci. 3 642–6)) GIA shows similar spatial patterns, but produces an average ice mass loss for the entire ice sheet that is 64 − 67 Gt yr −1 smaller. In the Northeast the recovered ice mass change is 46–49 Gt yr −1 (245–270%) more positive than that deduced from the other two corrections. By comparing the spatial and temporal variability of the GRACE estimates with trends of volume changes from altimetry and surface mass balance from RACMO, we show that the Wu et al (2010 Nature Geosci. 3 642–6) correction leads to a large mass increase in the Northeast that is inconsistent with independent observations. (paper)

  9. Determination of groundwater abstractions by means of GRACE data and Artificial Neural Networks

    Science.gov (United States)

    Gemitzi, Alexandra; Tsagkarakis, Konstantinos; Lakshmi, Venkat

    2017-04-01

    The EU Water Framework Directive requires for each groundwater body the determination of annual average rates of abstraction from all points providing more than 10m3 per day as well as groundwater level monitoring, so as to ensure that the available groundwater resource is not exceeded by the long-term annual average rate of abstraction. In order to acquire such information in situ observation networks are necessary. However, there are cases, e.g. Greece where WFD monitoring programme has not yet become operational due to bureaucratic, socioeconomic and often political constraints. The present study aims at determining groundwater use at the aquifer scale by using Gravity Recovery and Climate Experiment (GRACE) satellite data coupled with readily available meteorological data. Traditionally, GRACE data have been used at the global and regional scale due to their coarse resolution and the difficulties in disaggregating the various Total Water Storage (TWS) components. Previous works have evaluated the subsurface anomalies (ΔGW), using supplementary data sets and hydrologic modeling results in order to disaggregate GRACE TWS anomalies into their various components. Recent works however, have shown that changes in groundwater storage are dominating the GRACE Total Water Storage (TWS) changes, therefore it was though reasonable to use changes in Grace derived TWS in order to quantify abstractions from a groundwater body. Statistical downscaling was performed using an Artificial Neural Network in the form a Multilayer Perceptron model, in conjunction with local meteorological data. An ensemble of 100 ANNs provided a means of quantifying uncertainty and improving generalization. The methodology was applied in Rhodope area (NE Greece) and proved to be an efficient way of downscaling GRACE data in order to estimate the monthly quantity of water extracted from a certain aquifer. Although our methodology does not aim at estimating abstractions at single points, it manages

  10. Greenland Ice Sheet seasonal and spatial mass variability from model simulations and GRACE (2003-2012)

    Science.gov (United States)

    Alexander, Patrick M.; Tedesco, Marco; Schlegel, Nicole-Jeanne; Luthcke, Scott B.; Fettweis, Xavier; Larour, Eric

    2016-06-01

    Improving the ability of regional climate models (RCMs) and ice sheet models (ISMs) to simulate spatiotemporal variations in the mass of the Greenland Ice Sheet (GrIS) is crucial for prediction of future sea level rise. While several studies have examined recent trends in GrIS mass loss, studies focusing on mass variations at sub-annual and sub-basin-wide scales are still lacking. At these scales, processes responsible for mass change are less well understood and modeled, and could potentially play an important role in future GrIS mass change. Here, we examine spatiotemporal variations in mass over the GrIS derived from the Gravity Recovery and Climate Experiment (GRACE) satellites for the January 2003-December 2012 period using a "mascon" approach, with a nominal spatial resolution of 100 km, and a temporal resolution of 10 days. We compare GRACE-estimated mass variations against those simulated by the Modèle Atmosphérique Régionale (MAR) RCM and the Ice Sheet System Model (ISSM). In order to properly compare spatial and temporal variations in GrIS mass from GRACE with model outputs, we find it necessary to spatially and temporally filter model results to reproduce leakage of mass inherent in the GRACE solution. Both modeled and satellite-derived results point to a decline (of -178.9 ± 4.4 and -239.4 ± 7.7 Gt yr-1 respectively) in GrIS mass over the period examined, but the models appear to underestimate the rate of mass loss, especially in areas below 2000 m in elevation, where the majority of recent GrIS mass loss is occurring. On an ice-sheet-wide scale, the timing of the modeled seasonal cycle of cumulative mass (driven by summer mass loss) agrees with the GRACE-derived seasonal cycle, within limits of uncertainty from the GRACE solution. However, on sub-ice-sheet-wide scales, some areas exhibit significant differences in the timing of peaks in the annual cycle of mass change. At these scales, model biases, or processes not accounted for by models related

  11. Ground-Water Quality Data in the San Fernando-San Gabriel Study Unit, 2005 - Results from the California GAMA Program

    Science.gov (United States)

    Land, Michael; Belitz, Kenneth

    2008-01-01

    Ground-water quality in the approximately 460 square mile San Fernando-San Gabriel study unit (SFSG) was investigated between May and July 2005 as part of the Priority Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Assessment Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The San Fernando-San Gabriel study was designed to provide a spatially unbiased assessment of raw ground-water quality within SFSG, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 52 wells in Los Angeles County. Thirty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and seventeen wells were selected to aid in the evaluation of specific water-quality issues or changes in water chemistry along a historic ground-water flow path (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates], constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), 1,2,3-trichloropropane (1,2,3-TCP), and 1,4-dioxane], naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected at approximately one-fifth (11 of 52) of the wells, and the results for these

  12. GRACE gravity model: assssment in terms of deep ocean currents from hydrography and from the ECCO ocean model

    Science.gov (United States)

    Zlotnicki, V.; Stammer, D.; Fukumori, I.

    2003-01-01

    Here we assess the new generation of gravity models, derived from GRACE data. The differences between a global geoid model (one from GRACE data and one the well-known EGM-96), minus a Mean Sea Surface derived from over a decade of altimetric data are compared to hydrographic data from the Levitus compilation and to the ECCO numerical ocean model, which assimilates altimetry and other data.

  13. Human Factors Throughout the Life Cycle: Lessons Learned from the Shuttle Program. [Human Factors in Ground Processing

    Science.gov (United States)

    Kanki, Barbara G.

    2011-01-01

    With the ending of the Space Shuttle Program, it is critical that we not forget the Human Factors lessons we have learned over the years. At every phase of the life cycle, from manufacturing, processing and integrating vehicle and payload, to launch, flight operations, mission control and landing, hundreds of teams have worked together to achieve mission success in one of the most complex, high-risk socio-technical enterprises ever designed. Just as there was great diversity in the types of operations performed at every stage, there was a myriad of human factors that could further complicate these human systems. A single mishap or close call could point to issues at the individual level (perceptual or workload limitations, training, fatigue, human error susceptibilities), the task level (design of tools, procedures and aspects of the workplace), as well as the organizational level (appropriate resources, safety policies, information access and communication channels). While we have often had to learn through human mistakes and technological failures, we have also begun to understand how to design human systems in which individuals can excel, where tasks and procedures are not only safe but efficient, and how organizations can foster a proactive approach to managing risk and supporting human enterprises. Panelists will talk about their experiences as they relate human factors to a particular phase of the shuttle life cycle. They will conclude with a framework for tying together human factors lessons-learned into system-level risk management strategies.

  14. Statistically optimal estimation of Greenland Ice Sheet mass variations from GRACE monthly solutions using an improved mascon approach

    Science.gov (United States)

    Ran, J.; Ditmar, P.; Klees, R.; Farahani, H. H.

    2018-03-01

    We present an improved mascon approach to transform monthly spherical harmonic solutions based on GRACE satellite data into mass anomaly estimates in Greenland. The GRACE-based spherical harmonic coefficients are used to synthesize gravity anomalies at satellite altitude, which are then inverted into mass anomalies per mascon. The limited spectral content of the gravity anomalies is properly accounted for by applying a low-pass filter as part of the inversion procedure to make the functional model spectrally consistent with the data. The full error covariance matrices of the monthly GRACE solutions are properly propagated using the law of covariance propagation. Using numerical experiments, we demonstrate the importance of a proper data weighting and of the spectral consistency between functional model and data. The developed methodology is applied to process real GRACE level-2 data (CSR RL05). The obtained mass anomaly estimates are integrated over five drainage systems, as well as over entire Greenland. We find that the statistically optimal data weighting reduces random noise by 35-69%, depending on the drainage system. The obtained mass anomaly time-series are de-trended to eliminate the contribution of ice discharge and are compared with de-trended surface mass balance (SMB) time-series computed with the Regional Atmospheric Climate Model (RACMO 2.3). We show that when using a statistically optimal data weighting in GRACE data processing, the discrepancies between GRACE-based estimates of SMB and modelled SMB are reduced by 24-47%.

  15. Comparison of precision orbit derived density estimates for CHAMP and GRACE satellites

    Science.gov (United States)

    Fattig, Eric Dale

    Current atmospheric density models cannot adequately represent the density variations observed by satellites in Low Earth Orbit (LEO). Using an optimal orbit determination process, precision orbit ephemerides (POE) are used as measurement data to generate corrections to density values obtained from existing atmospheric models. Densities obtained using these corrections are then compared to density data derived from the onboard accelerometers of satellites, specifically the CHAMP and GRACE satellites. This comparison takes two forms, cross correlation analysis and root mean square analysis. The densities obtained from the POE method are nearly always superior to the empirical models, both in matching the trends observed by the accelerometer (cross correlation), and the magnitudes of the accelerometer derived density (root mean square). In addition, this method consistently produces better results than those achieved by the High Accuracy Satellite Drag Model (HASDM). For satellites orbiting Earth that pass through Earth's upper atmosphere, drag is the primary source of uncertainty in orbit determination and prediction. Variations in density, which are often not modeled or are inaccurately modeled, cause difficulty in properly calculating the drag acting on a satellite. These density variations are the result of many factors; however, the Sun is the main driver in upper atmospheric density changes. The Sun influences the densities in Earth's atmosphere through solar heating of the atmosphere, as well as through geomagnetic heating resulting from the solar wind. Data are examined for fourteen hour time spans between November 2004 and July 2009 for both the CHAMP and GRACE satellites. This data spans all available levels of solar and geomagnetic activity, which does not include data in the elevated and high solar activity bins due to the nature of the solar cycle. Density solutions are generated from corrections to five different baseline atmospheric models, as well as

  16. Measuring Zonal Transport Variability of the Antarctic Circumpolar Current Using GRACE Ocean Bottom Pressure

    Science.gov (United States)

    Makowski, J.; Chambers, D. P.; Bonin, J. A.

    2012-12-01

    Previous studies have suggested that ocean bottom pressure (OBP) can be used to measure the transport variability of the Antarctic Circumpolar Current (ACC). Using OBP data from the JPL ECCO model and the Gravity Recovery and Climate Experiment (GRACE), we examine the zonal transport variability of the ACC integrated between the major fronts between 2003-2010. The JPL ECCO data are used to determine average front positions for the time period studies, as well as where transport is mainly zonal. Statistical analysis will be conducted to determine the uncertainty of the GRACE observations using a simulated data set. We will also begin looking at low frequency changes and how coherent transport variability is from region to region of the ACC. Correlations with bottom pressure south of the ACC and the average basin transports will also be calculated to determine the probability of using bottom pressure south of the ACC as a means for describing the ACC dynamics and transport.

  17. Product shipping information using graceful labeling on undirected tree graph approach

    Science.gov (United States)

    Kuan, Yoong Kooi; Ghani, Ahmad Termimi Ab

    2017-08-01

    Product shipping information is the related information of an ordered product that ready to be shipped to the foreign customer's company, where the information represents as an irrefutable proof in black and white to the local manufacturer by E-mails. This messy and unordered list of information is stored in E-mail folders by the people incharge, which do not function in collating the information properly. So, in this paper, an algorithm is proposed on how to rearrange the messy information from the sequence of a path graph structure into a concise version of a caterpillar graph with achieving the concept of graceful labeling. The final graceful caterpillar graph consists of the full listed information together with the numbering, which able to assist people get the information fleetly for shipping arrangement procedure.

  18. Project GRACE A grid based search tool for the global digital library

    CERN Document Server

    Scholze, Frank; Vigen, Jens; Prazak, Petra; The Seventh International Conference on Electronic Theses and Dissertations

    2004-01-01

    The paper will report on the progress of an ongoing EU project called GRACE - Grid Search and Categorization Engine (http://www.grace-ist.org). The project participants are CERN, Sheffield Hallam University, Stockholm University, Stuttgart University, GL 2006 and Telecom Italia. The project started in 2002 and will finish in 2005, resulting in a Grid based search engine that will search across a variety of content sources including a number of electronic thesis and dissertation repositories. The Open Archives Initiative (OAI) is expanding and is clearly an interesting movement for a community advocating open access to ETD. However, the OAI approach alone may not be sufficiently scalable to achieve a truly global ETD Digital Library. Many universities simply offer their collections to the world via their local web services without being part of any federated system for archiving and even those dissertations that are provided with OAI compliant metadata will not necessarily be picked up by a centralized OAI Ser...

  19. Inter-comparison of ice sheet mass balance products from GRACE: ESA CCI Round Robin results

    DEFF Research Database (Denmark)

    Groth, A.; Horwath, M.; Horvath, A.

    -term satellite-based data products are generated for selected ECVs. Since ice sheet mass balance is an ECV parameter of highest interest, both the AIS_cci and the GIS_cci project will provide mass balance products based on satellite gravimetry data: (a) time series of monthly mass changes for individual drainage...... basins, and (b) gridded mass changes covering the entire ice sheet.Gravimetry Mass Balance (GMB) products are derived from data acquired by the GRACE (Gravity Recovery and Climate Experiment) mission. Although GRACE data have the advantage of being directly sensitive to mass changes, their limited...... drainage basins the GMB time series are compared to independent mass balance products based on satellite altimetry and firn densification information from a regional climate model. This inter-comparison has aided the algorithm definition for the operational ECV production....

  20. Monitoring mass changes in the Volta River basin using GRACE satellite gravity and TRMM precipitation

    Directory of Open Access Journals (Sweden)

    Vagner G. Ferreira

    Full Text Available GRACE satellite gravity data was used to estimate mass changes within the Volta River basin in West African for the period of January, 2005 to December, 2010. We also used the precipitation data from the Tropical Rainfall Measurement Mission (TRMM to determine relative contributions source to the seasonal hydrological balance within the Volta River basin. We found out that the seasonal mass change tends to be detected by GRACE for periods from 1 month in the south to 4 months in the north of the basin after the rainfall events. The results suggested a significant gain in water storage in the basin at reference epoch 2007.5 and a dominant annual cycle for the period under consideration for both in the mass changes and rainfall time series. However, there was a low correlation between mass changes and rainfall implying that there must be other processes which cause mass changes without rainfall in the upstream of the Volta River basin.

  1. Mass loss of Greenland from GRACE, IceSat and CryoSat

    DEFF Research Database (Denmark)

    Forsberg, René; Sørensen, Louise Sandberg; Fredenslund Levinsen, Joanna

    2013-01-01

    CryoSat data over the Greenland Ice Sheet are used to continue elevation height change data over the Greenland ice sheet, following a decade of detailed monitoring of ice sheet changes with GRACE and IceSat. The combination and validation of the different data for measuring changes is quantified...... by using available airborne lidar data from IceBridge and CryoVEx. There is a special challenge of using CryoSat as fill-in between EnviSat and Sentinel-3 for the longterm measurements of surface elevation changes, a key essential climate variable in the ESA Climate Change Initiative. Another challenge...... is the joint utilization of both altimetry and gravity field change measurements for consistent estimates of regional change patterns. In the paper we analyze GRACE, IceSat and CryoSat data since 2003, and present consistent estimates of overall mass changes with average values around -220 GT/year, showing...

  2. Insights into the Earth System mass variability from CSR-RL05 GRACE gravity fields

    Science.gov (United States)

    Bettadpur, S.

    2012-04-01

    The next-generation Release-05 GRACE gravity field data products are the result of extensive effort applied to the improvements to the GRACE Level-1 (tracking) data products, and to improvements in the background gravity models and processing methodology. As a result, the squared-error upper-bound in RL05 fields is half or less than the squared-error upper-bound in RL04 fields. The CSR-RL05 field release consists of unconstrained gravity fields as well as a regularized gravity field time-series that can be used for several applications without any post-processing error reduction. This paper will describe the background and the nature of these improvements in the data products, and provide an error characterization. We will describe the insights these new series offer in measuring the mass flux due to diverse Hydrologic, Oceanographic and Cryospheric processes.

  3. Seasonal Hydrological Loading in Southern Tibet Detected by Joint Analysis of GPS and GRACE.

    Science.gov (United States)

    Zou, Rong; Wang, Qi; Freymueller, Jeffrey T; Poutanen, Markku; Cao, Xuelian; Zhang, Caihong; Yang, Shaomin; He, Ping

    2015-12-04

    In southern Tibet, ongoing vertical and horizontal motions due to the collision between India and Eurasia are monitored by large numbers of global positioning system (GPS) continuous and campaign sites installed in the past decade. Displacements measured by GPS usually include tectonic deformation as well as non-tectonic, time-dependent signals. To estimate the regional long-term tectonic deformation using GPS more precisely, seasonal elastic deformation signals associated with surface loading must be removed from the observations. In this study, we focus on seasonal variation in vertical and horizontal motions of southern Tibet by performing a joint analysis of GRACE (Gravity Recovery and Climate Experiment) and GPS data, not only using continuous sites but also GPS campaign-mode sites. We found that the GPS-observed and GRACE-modeled seasonal oscillations are in good agreements, and a seasonal displacement model demonstrates that the main reason for seasonal variations in southern Tibet is from the summer monsoon and its precipitation. The biggest loading appears from July to August in the summer season. Vertical deformations observed by GPS and modeled by GRACE are two to three times larger than horizontal oscillations, and the north components demonstrate larger amplitudes than the east components. We corrected the GPS position time series using the GRACE-modeled seasonal variations, which gives significant reductions in the misfit and weighted root-mean-squares (WRMS). Misfit (χ2 divided by degree of freedom) reductions for campaign sites range between 20% and 56% for the vertical component, and are much smaller for the horizontal components. Moreover, time series of continuous GPS (cGPS) sites near the 2015 Nepal earthquakes must be corrected using appropriate models of seasonal loading for analyzing postseismic deformation to avoid biasing estimates of the postseismic relaxation.

  4. Measuring Two Decades of Ice Mass Loss using GRACE and SLR

    Science.gov (United States)

    Bonin, J. A.; Chambers, D. P.

    2016-12-01

    We use Satellite Laser Ranging (SLR) to extend the time series of ice mass change back in time to 1994. The SLR series is of far lesser spatial resolution than GRACE, so we apply a constrained inversion technique to better localize the signal. We approximate the likely errors due to SLR's measurement errors combined with the inversion errors from using a low-resolution series, then estimate the interannual mass change over Greenland and Antarctica.

  5. Seasonal Mass Changes in the Red Sea Observed By GPS and Grace

    Science.gov (United States)

    Alothman, A. O.; Fing, W.; Fernandes, R. M. S.; Bos, M. S.; Elsaka, B.

    2014-12-01

    The Red Sea is a semi-enclosed basin and exchanges water with the Gulf of Aden through the strait of Bab-el-Mandeb at the southern part of the sea. Its circulation is affected by the Indian Monsoon through its connection via the Gulf of Aden. Two distinctive (in summer and in winter) seasonal signals represent the water exchange. To understand the seasonal mass changes in the Red Sea, estimates of the mass changes based on two geodetic techniques are presented: from the Gravity Recovery and Climate Experiment (GRACE) and from the Global Navigation Satellite System (GNSS). The GRACE solutions were truncated up to spherical harmonic degree and order degree 60 to estimate the average monthly mass change in the atmosphere and ocean from models (several hours). GNSS solution is based on observations from four stations along the Red Sea that have been acquired in continuous mode starting in 2007 (having at least 5 years' data-span). The time series analysis of the observed GNSS vertical deformation of these sites has been analyzed. The results revealed that the GNSS observed vertical loading agrees with the atmospheric loading (ATML) assuming that the hydrological signal along the costs of the Red sea is negligible. Computed values of daily vertical atmospheric loading using the NCEP surface pressure data (Inverted Barometer IB) for the 4 stations for 2003 until 2013 are provided. Comparison of the GRACE and GNSS solutions has shown significant annual mass variations in the Red Sea (about 15 cm annual amplitude). After removing the atmospheric effect (ATML), the ocean loading can be observed by GNSS and GRACE estimates in the Red Sea.

  6. Mass-induced [|#8#|]Sea Level Variations in the Red Sea from Satellite Altimetry and GRACE

    Science.gov (United States)

    Feng, W.; Lemoine, J.; Zhong, M.; Hsu, H.

    2011-12-01

    We have analyzed mass-induced sea level variations (SLVs) in the Red Sea from steric-corrected altimetry and GRACE between January 2003 and December 2010. The steric component of SLVs in the Red Sea calculated from climatological temperature and salinity data is relatively small and anti-phase with the mass-induced SLV. The total SLV in the Red Sea is mainly driven by the mass-induced SLV, which increases in winter when the Red Sea gains the water mass from the Gulf of Aden and vice versa in summer. Spatial and temporal patterns of mass-induced SLVs in the Red Sea from steric-corrected altimetry agree very well with GRACE observations. Both of two independent observations show high annual amplitude in the central Red Sea (>20cm). Total mass-induced SLVs in the Red Sea from two independent observations have similar annual amplitude and phase. One main purpose of our work is to see whether GRGS's ten-day GRACE results can observe intra-seasonal mass change in the Red Sea. The wavelet coherence analysis indicates that GRGS's results show the high correlation with the steric-corrected SLVs on intra-seasonal time scale. The agreement is excellent for all the time-span until 1/3 year period and is patchy between 1/3 and 1/16 year period. Furthermore, water flux estimates from current-meter arrays and moorings show mass gain in winter and mass loss in summer, which is also consistent with altimetry and GRACE.

  7. Development and Release of a GRACE-FO "Grand Simulation" Data Set by JPL

    Science.gov (United States)

    Fahnestock, E.; Yuan, D. N.; Wiese, D. N.; McCullough, C. M.; Harvey, N.; Sakumura, C.; Paik, M.; Bertiger, W. I.; Wen, H. Y.; Kruizinga, G. L. H.

    2017-12-01

    The GRACE-FO mission, to be launched early in 2018, will require several stages of data processing to be performed within its Science Data System (SDS). In an effort to demonstrate effective implementation and inter-operation of this level 1, 2, and 3 data processing, and to verify its combined ability to recover a truth Earth gravity field to within top-level requirements, the SDS team has performed a system test which it has termed the "Grand Simulation". This process starts with iteration to converge on a mutually consistent integrated truth orbit, non-gravitational acceleration time history, and spacecraft attitude time history, generated with the truth models for all elements of the integrated system (geopotential, both GRACE-FO spacecraft, constellation of GPS spacecraft, etc.). Level 1A data products are generated and then the GPS time to onboard receiver time clock error is introduced into those products according to a realistic truth clock offset model. The various data products are noised according to current best estimate noise models, and then some are used within a precision orbit determination and clock offset estimation/recovery process. Processing from level 1A to level 1B data products uses the recovered clock offset to correct back to GPS time, and performs gap-filling, compression, etc. This exercises nearly all software pathways intended for processing actual GRACE-FO science data. Finally, a monthly gravity field is recovered and compared against the truth background field. In this talk we briefly summarize the resulting performance vs. requirements, and lessons learned in the system test process. Finally, we provide information for use of the level 1B data set by the general community for gravity solution studies and software trials in anticipation of operational GRACE-FO data. ©2016 California Institute of Technology. Government sponsorship acknowledged.

  8. Antarctic contribution to sea level rise observed by GRACE with improved GIA correction

    Science.gov (United States)

    Ivins, Erik R.; James, Thomas S.; Wahr, John; Schrama, Ernst J. O.; Landerer, Felix W.; Simon, Karen M.

    2013-06-01

    Antarctic volume changes during the past 21 thousand years are smaller than previously thought, and here we construct an ice sheet history that drives a forward model prediction of the glacial isostatic adjustment (GIA) gravity signal. The new model, in turn, should give predictions that are constrained with recent uplift data. The impact of the GIA signal on a Gravity Recovery and Climate Experiment (GRACE) Antarctic mass balance estimate depends on the specific GRACE analysis method used. For the method described in this paper, the GIA contribution to the apparent surface mass change is re-evaluated to be +55±13 Gt/yr by considering a revised ice history model and a parameter search for vertical motion predictions that best fit the GPS observations at 18 high-quality stations. Although the GIA model spans a range of possible Earth rheological structure values, the data are not yet sufficient for solving for a preferred value of upper and lower mantle viscosity nor for a preferred lithospheric thickness. GRACE monthly solutions from the Center for Space Research Release 04 (CSR-RL04) release time series from January 2003 to the beginning of January 2012, uncorrected for GIA, yield an ice mass rate of +2.9± 29 Gt/yr. The new GIA correction increases the solved-for ice mass imbalance of Antarctica to -57±34 Gt/yr. The revised GIA correction is smaller than past GRACE estimates by about 50 to 90 Gt/yr. The new upper bound to the sea level rise from the Antarctic ice sheet, averaged over the time span 2003.0-2012.0, is about 0.16±0.09 mm/yr.

  9. Arctic Ocean gravity, geoid and sea-ice freeboard heights from ICESat and GRACE

    DEFF Research Database (Denmark)

    Forsberg, René; Skourup, Henriette

    2005-01-01

    Gravity Project in combination with GRACE gravity field models to derive an improved Arctic geoid model. This model is then used to convert ICESat measurements to sea-ice freeboard heights with a coarse lowest-level surface method. The derived freeboard heights show a good qualitative agreement...... all major tectonic features of the Arctic Ocean, and has an accuracy of 6 mGal compared to recent airborne gravity data, illustrating the usefulness of ICESat data for gravity field determination....

  10. Global and regional seasonal variations of the geoid detected by GRACE

    Czech Academy of Sciences Publication Activity Database

    Kostelecký, J.; Bezděk, Aleš; Klokočník, Jaroslav

    2013-01-01

    Roč. 10, č. 3 (2013), s. 285-291 ISSN 1214-9705 R&D Projects: GA ČR GA13-36843S Grant - others:EU(XE) NTIS CZ1.05/1.1.00/02.0090 Institutional support: RVO:67985815 Keywords : GRACE mission * seasonal variations * geoid Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.667, year: 2013

  11. Multidisciplinary Studies of the Fate and Transport of Contaminants in Ground Water at the U.S. Geological Survey Cape Cod Toxic Substances Hydrology Program Research Site, Massachusetts

    Science.gov (United States)

    Leblanc, D. R.; Smith, R. L.; Kent, D. B.; Barber, L. B.; Harvey, R. W.

    2008-12-01

    The U.S. Geological Survey conducts multidisciplinary research on the physical, chemical, and microbiological processes affecting ground-water contaminants of global concern at its Cape Cod Toxic Substances Hydrology Program site in Massachusetts, USA. The work centers on a 6-kilometer-long plume of treated wastewater in a glacial sand and gravel aquifer. The plume is characterized by distinct geochemical zones caused by the biodegradation of organic materials in treated wastewater that was disposed to the aquifer by rapid infiltration during the period 1936-95. A core group of hydrogeologists, geochemists, microbiologists, and geophysicists has been involved in the research effort for more than two decades. The effort has been enhanced by stable funding, a readily accessible site, a relatively simple hydrologic setting, and logistical support from an adjacent military base. The research team uses a three-part approach to plan and conduct research at the site. First, detailed spatial and temporal monitoring of the plume since the late 1970s provides field evidence of important contaminant-transport processes and provides the basis for multidisciplinary, process-oriented studies. Second, ground-water tracer experiments are conducted in various geochemical zones in the plume to study factors that control the rate and extent of contaminant transport. Several arrays of multilevel sampling devices, including an array with more than 15,000 individual sampling points, are used to conduct these experiments. Plume-scale (kilometers) and tracer-test-scale (1- 100 meters) studies are complemented by laboratory experiments and mathematical modeling of flow and reactive transport. Third, results are applied to the treated-wastewater plume, other contaminant plumes at the military base, and other sites nationally to evaluate the applicability of the findings and to point toward further research. Examples of findings to date include that (1) macrodispersivity can be related to

  12. Intensified water storage loss by biomass burning in Kalimantan: Detection by GRACE

    Science.gov (United States)

    Han, Jiancheng; Tangdamrongsub, Natthachet; Hwang, Cheinway; Abidin, Hasanuddin Z.

    2017-03-01

    Biomass burning is the principal tool for land clearing and a primary driver of land use change in Kalimantan (the Indonesian part of Borneo island). Biomass burning here has consumed millions of hectares of peatland and swamp forests. It also degrades air quality in Southeast Asia, perturbs the global carbon cycle, threatens ecosystem health and biodiversity, and potentially affects the global water cycle. Here we present the optimal estimate of water storage changes over Kalimantan from NASA's Gravity Recovery and Climate Experiment (GRACE). Over August 2002 to December 2014, our result shows a north-south dipole pattern in the long-term changes in terrestrial water storage (TWS) and groundwater storage (GWS). Both TWS and GWS increase in the northern part of Kalimantan, while they decrease in the southern part where fire events are the most severe. The loss rates in TWS and GWS in the southern part are 0.56 ± 0.11 cm yr-1 and 0.55 ± 0.10 cm yr-1, respectively. We use GRACE estimates, burned area, carbon emissions, and hydroclimatic data to study the relationship between biomass burning and water storage losses. The analysis shows that extensive biomass burning results in excessive evapotranspiration, which then increases long-term water storage losses in the fire-prone region of Kalimantan. Our results show the potentials of GRACE and its follow-on missions in assisting water storage and fire managements in a region with extensive biomass burning such as Kalimantan.

  13. The celestial mechanics approach: application to data of the GRACE mission

    Science.gov (United States)

    Beutler, Gerhard; Jäggi, Adrian; Mervart, Leoš; Meyer, Ulrich

    2010-11-01

    The celestial mechanics approach (CMA) has its roots in the Bernese GPS software and was extensively used for determining the orbits of high-orbiting satellites. The CMA was extended to determine the orbits of Low Earth Orbiting satellites (LEOs) equipped with GPS receivers and of constellations of LEOs equipped in addition with inter-satellite links. In recent years the CMA was further developed and used for gravity field determination. The CMA was developed by the Astronomical Institute of the University of Bern (AIUB). The CMA is presented from the theoretical perspective in (Beutler et al. 2010). The key elements of the CMA are illustrated here using data from 50 days of GPS, K-Band, and accelerometer observations gathered by the Gravity Recovery And Climate Experiment (GRACE) mission in 2007. We study in particular the impact of (1) analyzing different observables [Global Positioning System (GPS) observations only, inter-satellite measurements only], (2) analyzing a combination of observations of different types on the level of the normal equation systems (NEQs), (3) using accelerometer data, (4) different orbit parametrizations (short-arc, reduced-dynamic) by imposing different constraints on the stochastic orbit parameters, and (5) using either the inter-satellite ranges or their time derivatives. The so-called GRACE baseline, i.e., the achievable accuracy of the GRACE gravity field for a particular solution strategy, is established for the CMA.

  14. Seasonal Mass Changes and Crustal Vertical Deformations Constrained by GPS and GRACE in Northeastern Tibet

    Directory of Open Access Journals (Sweden)

    Yuanjin Pan

    2016-08-01

    Full Text Available Surface vertical deformation includes the Earth’s elastic response to mass loading on or near the surface. Continuous Global Positioning System (CGPS stations record such deformations to estimate seasonal and secular mass changes. We used 41 CGPS stations to construct a time series of coordinate changes, which are decomposed by empirical orthogonal functions (EOFs, in northeastern Tibet. The first common mode shows clear seasonal changes, indicating seasonal surface mass re-distribution around northeastern Tibet. The GPS-derived result is then assessed in terms of the mass changes observed in northeastern Tibet. The GPS-derived common mode vertical change and the stacked Gravity Recovery and Climate Experiment (GRACE mass change are consistent, suggesting that the seasonal surface mass variation is caused by changes in the hydrological, atmospheric and non-tidal ocean loads. The annual peak-to-peak surface mass changes derived from GPS and GRACE results show seasonal oscillations in mass loads, and the corresponding amplitudes are between 3 and 35 mm/year. There is an apparent gradually increasing gravity between 0.1 and 0.9 μGal/year in northeast Tibet. Crustal vertical deformation is determined after eliminating the surface load effects from GRACE, without considering Glacial Isostatic Adjustment (GIA contribution. It reveals crustal uplift around northeastern Tibet from the corrected GPS vertical velocity. The unusual uplift of the Longmen Shan fault indicates tectonically sophisticated processes in northeastern Tibet.

  15. Separation of GRACE geoid time-variations using Independent Component Analysis

    Science.gov (United States)

    Frappart, F.; Ramillien, G.; Maisongrande, P.; Bonnet, M.

    2009-12-01

    Independent Component Analysis (ICA) is a blind separation method based on the simple assumptions of the independence of the sources and the non-Gaussianity of the observations. An approach based on this numerical method is used here to extract hydrological signals over land and oceans from the polluting striping noise due to orbit repetitiveness and present in the GRACE global mass anomalies. We took advantage of the availability of monthly Level-2 solutions from three official providers (i.e., CSR, JPL and GFZ) that can be considered as different observations of the same phenomenon. The efficiency of the methodology is first demonstrated on a synthetic case. Applied to one month of GRACE solutions, it allows to clearly separate the total water storage change from the meridional-oriented spurious gravity signals on the continents but not on the oceans. This technique gives results equivalent as the destriping method for continental water storage for the hydrological patterns with less smoothing. This methodology is then used to filter the complete series of the 2002-2009 GRACE solutions.

  16. Evaluating short-term hydro-meteorological fluxes using GRACE-derived water storage changes

    Science.gov (United States)

    Eicker, A.; Jensen, L.; Springer, A.; Kusche, J.

    2017-12-01

    Atmospheric and terrestrial water budgets, which represent important boundary conditions for both climate modeling and hydrological studies, are linked by evapotranspiration (E) and precipitation (P). These fields are provided by numerical weather prediction models and atmospheric reanalyses such as ERA-Interim and MERRA-Land; yet, in particular the quality of E is still not well evaluated. Via the terrestrial water budget equation, water storage changes derived from products of the Gravity Recovery and Climate Experiment (GRACE) mission, combined with runoff (R) data can be used to assess the realism of atmospheric models. In this contribution we will investigate the closure of the water balance for short-term fluxes, i.e. the agreement of GRACE water storage changes with P-E-R flux time series from different (global and regional) atmospheric reanalyses, land surface models, as well as observation-based data sets. Missing river runoff observations will be extrapolated using the calibrated rainfall-runoff model GR2M. We will perform a global analysis and will additionally focus on selected river basins in West Africa. The investigations will be carried out for various temporal scales, focusing on short-term fluxes down to daily variations to be detected in daily GRACE time series.

  17. Global sea level variations from altimetry, GRACE and Argo data over 2005–2014

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2015-07-01

    Full Text Available Total sea level variations (SLVs are caused by two major components: steric variations due to thermal expansion of seawater, and mass-induced variations due to mass exchange between ocean and land. In this study, the global SLV and its steric and mass components were estimated by satellite altimetry, Argo float data and the Gravity Recovery and Climate Experiment (GRACE data over 2005–2014. Space gravimetry observations from GRACE suggested that two-thirds of the global mean sea level rise rate observed by altimetry (i.e., 3.1 ± 0.3 mm/a from 2005 to 2014 could be explained by an increase in ocean mass. Furthermore, the global mean sea level was observed to drop significantly during the 2010/2011 La Niña event, which may be attributed to the decline of ocean mass and steric SLV. Since early 2011, the global mean sea level began to rise rapidly, which was attributed to an increase in ocean mass. The findings in this study suggested that the global mean sea-level budget was closed from 2005 to 2014 based on altimetry, GRACE, and Argo data.

  18. Impact of combining GRACE and GOCE gravity data on ocean circulation estimates

    Directory of Open Access Journals (Sweden)

    T. Janjić

    2012-02-01

    Full Text Available With the focus on the Southern Ocean circulation, results of assimilation of multi-mission-altimeter data and the GRACE/GOCE gravity data into the finite element ocean model (FEOM are investigated. We use the geodetic method to obtain the dynamical ocean topography (DOT. This method combines the multi-mission-altimeter sea surface height and the GRACE/GOCE gravity field. Using the profile approach, the spectral consistency of both fields is achieved by filtering the sea surface height and the geoid. By combining the GRACE and GOCE data, a considerably shorter filter length can be used, which results in more DOT details. We show that this increase in resolution of measured DOT carries onto the results of data assimilation for the surface data. By assimilating only absolute dynamical topography data using the ensemble Kalman filter, we were able to improve modeled fields. Results are closer to observations which were not used for assimilation and lie outside the area covered by altimetry in the Southern Ocean (e.g. temperature of surface drifters or deep temperatures in the Weddell Sea area at 800 m depth derived from Argo composite.

  19. Contributions of GRACE to Understanding of Spatial Distribution of Spring Flooding in Snow-dominated Afghan Watersheds

    Science.gov (United States)

    Roningen, J. M.; Daly, S. F.; Vuyovich, C.

    2012-12-01

    In Afghanistan, where both historical and current in situ hydrologic records are extremely limited, the development and stability operations communities require guidance as to how to best utilize capabilities in remote sensing of the water cycle to understand and predict seasonal flooding. In this study, three versions of Level 3 GRACE datasets (CSR, CSR 4.1 and GRGS) are compared to TRMM 3B42 products, SSM/I-derived snow water equivalent products (SWE), and MODIS-derived flooding extents to assess their potential for contributing to an understanding of the spatial and temporal patterns of spring flooding in Afghanistan from the period 2002-2012. GRACE, which allows for assessment of correlations between small-scale temporal changes in the gravitational field of the earth with changes in the total water storage in the hydrosphere, opens the possibility for incorporation of subsurface components of the hydrologic cycle into remote monitoring and modeling of water resources. GRACE data exhibit clear seasonal fluctuations in many areas of Afghanistan, but an assessment is required of the extent to which this data can be disaggregated spatially and related to geographic patterns of precipitation, snowmelt and flooding. In this study, TRMM 3B42 and SSM/I-derived SWE datasets were used as proxies for measured precipitation. These datasets were convolved with a Gaussian filter with a 300 km half-radius at each reported GRACE data point in order to compensate for spatial correlation ('leakage' effects) in the GRACE data. In mountainous and snowmelt-dominated basins such as the majority of those in this study, GRACE analyses that make use of land surface model (LSM) derived estimates may not provide adequate characterization of snow water equivalent and soil moisture in this region. Therefore, soil and subsurface moisture were evaluated as a single storage component using the GRACE data, and flooding occurrence was evaluated as a qualitative surface expression of this

  20. Grounding Anger Management

    Directory of Open Access Journals (Sweden)

    Odis E. Simmons, PhD

    2017-06-01

    Full Text Available One of the things that drew me to grounded theory from the beginning was Glaser and Strauss’ assertion in The Discovery of Grounded Theory that it was useful as a “theoretical foothold” for practical applications (p. 268. From this, when I was a Ph.D student studying under Glaser and Strauss in the early 1970s, I devised a GT based approach to action I later came to call “grounded action.” In this short paper I’ll present a very brief sketch of an anger management program I developed in 1992, using grounded action. I began my research by attending a two-day anger management training workshop designed for training professionals in the most commonly used anger management model. Like other intervention programs I had seen, this model took a psychologizing and pathologizing approach to the issue. Following this, I sat through the full course of an anger management program that used this model, observing the reactions of the participants and the approach of the facilitator. Following each session I conducted open-ended interviews with most of the participants, either individually or in groups of two or three. I had also done previous research in counseling and social work contexts that turned out to be very relevant to an anger management program design.

  1. Analysis of seasonal position variation for selected GNSS sites in Poland using loading modelling and GRACE data

    Directory of Open Access Journals (Sweden)

    Marcin Rajner

    2017-07-01

    Full Text Available In this study we compared weekly GNSS position time series with modelled values of crustal deformations on the basis of Gravity Recovery and Climate Experiment (GRACE data. The Global Navigation Satellite Systems (GNSS time series were taken from homogeneously reprocessed global network solutions within the International GNSS Service (IGS Reprocessing 1 project and from regional solutions performed by Warsaw University of Technology (WUT European Permanent Network (EPN Local Analysis Center (LAC within the EPN reprocessing project. Eight GNSS sites from the territory of Poland with observation timespans between 2.5 and 13 years were selected for this study. The Total Water Equivalent (TWE estimation from GRACE data was used to compute deformations using the Green's function formalism. High frequency components were removed from GRACE data to avoid aliasing problems. Since GRACE observes mainly the mass transport in continental storage of water, we also compared GRACE deformations and the GNSS position time series, with the deformations computed on the basis of a hydrosphere model. We used the output of Water GAP Hydrology Model (WGHM to compute deformations in the same manner as for the GRACE data. The WGHM gave slightly larger amplitudes than GNSS and GRACE. The atmospheric non-tidal loading effect was removed from GNSS position time series before comparing them with modelled deformations. The results confirmed that the major part of observed seasonal variations for GNSS vertical components can be attributed to the hydrosphere loading. The results for these components agree very well both in the amplitude and phase. The decrease in standard deviation of the residual GNSS position time series for vertical components corrected for the hydrosphere loading reached maximally 36% and occurred for all but one stations for both global and regional solutions. For horizontal components the amplitudes are about three times smaller than for vertical

  2. [Management of NSTEMI in a hospital without interventional cardiology and without use of GRACE score: Does the clinician appreciation match the GRACE score calculated retrospectively for the coronarography delay?

    Science.gov (United States)

    Bouriche, F; Yvorra, S; Hassan, A; Paganelli, F; Bonello, L; Luigi, S; Attia, F

    2017-11-01

    The management of non-ST segment elevation acute coronary syndromes (NSTEACS) remains an issue for mobidity, mortality, and an economic stake. The first aim of the study was to evaluate the additional value of the GRACE score for the compliance with the recommended times to coronary angiography in an hospital without interventional cardiology. We also analysed the in-hospital and 6-month mortality and the predictive factors of compliance for the coronarography delays. Retrospective monocenter cross-sectional study including consecutive patients with chest pain suggestive of a NSTEACS during 1 year. Data of the delay to coronarography were collected and GRACE score was calculated a posteriori. The time to perform coronary angiography was non-compliant in 49% of cases (27 patients out of 55). The calculation of the GRACE score would have allowed correcting the delay for two patients of our cohort. Clinical appreciation, troponin elevation, ECG modifications were associated with the delay compliance. Age <75 years predisposed to recommended delays. Renal failure and history of coronaropathy were significantly associated with non compliant delays. A non-compliant delay was significantly associated with higher mortality. In our experience, the knowledge of the GRACE score had little impact on the timing of coronary angiography. However, as a predictor of mid and long term mortality, GRACE score remains SCA ST+ useful to intensify surveillance of high-risk patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. TFTR grounding scheme and ground-monitor system

    International Nuclear Information System (INIS)

    Viola, M.

    1983-01-01

    The Tokamak Fusion Test Reactor (TFTR) grounding system utilizes a single-point ground. It is located directly under the machine, at the basement floor level, and is tied to the building perimeter ground. Wired to this single-point ground, via individual 500 MCM insulated cables, are: the vacuum vessel; four toroidal field coil cases/inner support structure quadrants; umbrella structure halves; the substructure ring girder; radial beams and columns; and the diagnostic systems. Prior to the first machine operation, a ground-loop removal program was initiated. It required insulation of all hangers and supports (within a 35-foot radius of the center of the machine) of the various piping, conduits, cable trays, and ventilation systems. A special ground-monitor system was designed and installed. It actively monitors each of the individual machine grounds to insure that there are no inadvertent ground loops within the machine structure or its ground and that the machine grounds are intact prior to each pulse. The TFTR grounding system has proven to be a very manageable system and one that is easy to maintain

  4. Recent changes in terrestrial water storage in the Upper Nile Basin: an evaluation of commonly used gridded GRACE products

    Directory of Open Access Journals (Sweden)

    M. Shamsudduha

    2017-09-01

    Full Text Available GRACE (Gravity Recovery and Climate Experiment satellite data monitor large-scale changes in total terrestrial water storage (ΔTWS, providing an invaluable tool where in situ observations are limited. Substantial uncertainty remains, however, in the amplitude of GRACE gravity signals and the disaggregation of TWS into individual terrestrial water stores (e.g. groundwater storage. Here, we test the phase and amplitude of three GRACE ΔTWS signals from five commonly used gridded products (i.e. NASA's GRCTellus: CSR, JPL, GFZ; JPL-Mascons; GRGS GRACE using in situ data and modelled soil moisture from the Global Land Data Assimilation System (GLDAS in two sub-basins (LVB: Lake Victoria Basin; LKB: Lake Kyoga Basin of the Upper Nile Basin. The analysis extends from January 2003 to December 2012, but focuses on a large and accurately observed reduction in ΔTWS of 83 km3 from 2003 to 2006 in the Lake Victoria Basin. We reveal substantial variability in current GRACE products to quantify the reduction of ΔTWS in Lake Victoria that ranges from 80 km3 (JPL-Mascons to 69 and 31 km3 for GRGS and GRCTellus respectively. Representation of the phase in TWS in the Upper Nile Basin by GRACE products varies but is generally robust with GRGS, JPL-Mascons, and GRCTellus (ensemble mean of CSR, JPL, and GFZ time-series data, explaining 90, 84, and 75 % of the variance respectively in "in situ" or "bottom-up" ΔTWS in the LVB. Resolution of changes in groundwater storage (ΔGWS from GRACE ΔTWS is greatly constrained by both uncertainty in changes in soil-moisture storage (ΔSMS modelled by GLDAS LSMs (CLM, NOAH, VIC and the low annual amplitudes in ΔGWS (e.g. 1.8–4.9 cm observed in deeply weathered crystalline rocks underlying the Upper Nile Basin. Our study highlights the substantial uncertainty in the amplitude of ΔTWS that can result from different data-processing strategies in commonly used, gridded GRACE products; this uncertainty is

  5. Recent changes in terrestrial water storage in the Upper Nile Basin: an evaluation of commonly used gridded GRACE products

    Science.gov (United States)

    Shamsudduha, Mohammad; Taylor, Richard G.; Jones, Darren; Longuevergne, Laurent; Owor, Michael; Tindimugaya, Callist

    2017-09-01

    GRACE (Gravity Recovery and Climate Experiment) satellite data monitor large-scale changes in total terrestrial water storage (ΔTWS), providing an invaluable tool where in situ observations are limited. Substantial uncertainty remains, however, in the amplitude of GRACE gravity signals and the disaggregation of TWS into individual terrestrial water stores (e.g. groundwater storage). Here, we test the phase and amplitude of three GRACE ΔTWS signals from five commonly used gridded products (i.e. NASA's GRCTellus: CSR, JPL, GFZ; JPL-Mascons; GRGS GRACE) using in situ data and modelled soil moisture from the Global Land Data Assimilation System (GLDAS) in two sub-basins (LVB: Lake Victoria Basin; LKB: Lake Kyoga Basin) of the Upper Nile Basin. The analysis extends from January 2003 to December 2012, but focuses on a large and accurately observed reduction in ΔTWS of 83 km3 from 2003 to 2006 in the Lake Victoria Basin. We reveal substantial variability in current GRACE products to quantify the reduction of ΔTWS in Lake Victoria that ranges from 80 km3 (JPL-Mascons) to 69 and 31 km3 for GRGS and GRCTellus respectively. Representation of the phase in TWS in the Upper Nile Basin by GRACE products varies but is generally robust with GRGS, JPL-Mascons, and GRCTellus (ensemble mean of CSR, JPL, and GFZ time-series data), explaining 90, 84, and 75 % of the variance respectively in "in situ" or "bottom-up" ΔTWS in the LVB. Resolution of changes in groundwater storage (ΔGWS) from GRACE ΔTWS is greatly constrained by both uncertainty in changes in soil-moisture storage (ΔSMS) modelled by GLDAS LSMs (CLM, NOAH, VIC) and the low annual amplitudes in ΔGWS (e.g. 1.8-4.9 cm) observed in deeply weathered crystalline rocks underlying the Upper Nile Basin. Our study highlights the substantial uncertainty in the amplitude of ΔTWS that can result from different data-processing strategies in commonly used, gridded GRACE products; this uncertainty is disregarded in analyses of

  6. Grit or Grace: Packing for the Camino de Santiago

    OpenAIRE

    Havard, Megan

    2017-01-01

    As the director of a new collegiate study-abroad program that will invite students to complete a segment of a Christian pilgrimage across northern Spain, the Camino de Santiago (Way of St. James), I am tasked with setting the expectations of students, parents and administrators, and with addressing the needs of student travellers. The present chapter analyses several genres of cultural artefacts that novice pilgrims, such as my students, are likely to encounter prior to departure: travel guid...

  7. Ground water

    International Nuclear Information System (INIS)

    Osmond, J.K.; Cowart, J.B.

    1982-01-01

    The subject is discussed under the headings: background and theory (introduction; fractionation in the hydrosphere; mobility factors; radioisotope evolution and aquifer classification; aquifer disequilibria and geochemical fronts); case studies (introduction; (a) conservative, and (b) non-conservative, behaviour); ground water dating applications (general requirements; radon and helium; radium isotopes; uranium isotopes). (U.K.)

  8. Ground water

    International Nuclear Information System (INIS)

    Osmond, J.K.; Cowart, J.B.

    1992-01-01

    The great variations in concentrations and activity ratios of 234 U/ 238 U in ground waters and the features causing elemental and isotopic mobility in the hydrosphere are discussed. Fractionation processes and their application to hydrology and other environmental problems such as earthquake, groundwater and aquifer dating are described. (UK)

  9. The use of GRACE data to monitor natural and anthropogenic induced variations in water availability across Africa

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Mohamed; Sultan, Mohamed; Wahr, John; Yan, Eugene

    2014-05-27

    Inter-annual trends in terrestrial water storage (TWS) were extracted from monthly (01/2003–09/2012) Gravity Recovery and Climate Experiment (GRACE) data acquired over Africa and correlated (in a geographic information system [GIS] environment) with relevant temporal remote sensing, geologic, and hydrologic datasets. Findings include the following: (1) large sectors of Africa are undergoing statistically significant TWS variations (+ 44 mm/yr to -15 mm/yr) due to natural and anthropogenic causes; (2) warming of the tropical Atlantic Ocean apparently intensified Atlantic monsoons and increased precipitation and TWS over western and central Africa; (3) warming in the central Indian Ocean decreased precipitation and TWS over eastern Africa; (4) the high frequency of flooding events increased TWS over the Zambezi and Okavango basins; (5) extraction of fossil groundwater decreased TWS over the Saharan aquifers; (6) deforestation decreased TWS in three subbasins (Ubangi, Congo, and Sangha) of the Congo River Basin; and (7) the construction of dams increased TWS in the Blue Nile and Atbara subbasins. Given the 10 years of monthly GRACE data acquired on the subbasin scale across the globe, as well as the plans underway for deployment of a GRACE-FO and GRACE-II, using GRACE-derived TWS data should be considered an alternative, viable index for measuring temporal and spatial variations in water availability.

  10. Earth Surface Deformation in the North China Plain Detected by Joint Analysis of GRACE and GPS Data

    Science.gov (United States)

    Liu, Renli; Li, Jiancheng; Fok, Hok Sum; Shum, C.K.; Li, Zhao

    2014-01-01

    Mass redistribution of the Earth causes variable loading that deforms the solid Earth. While most recent studies using geodetic techniques focus on regions (such as the Amazon basin and the Nepal Himalayas) with large seasonal deformation amplitudes on the order of 1–4 cm due to hydrologic loading, few such studies have been conducted on the regions where the seasonal deformation amplitude is half as large. Here, we use joint GPS and GRACE data to investigate the vertical deformation due to hydrologic loading in the North China Plain, where significant groundwater depletion has been reported. We found that the GPS- and GRACE-derived secular trends and seasonal signals are in good agreement, with an uplift magnitude of 1–2 mm/year and a correlation of 85.0%–98.5%, respectively. This uplift rate is consistent with groundwater depletion rate estimated from GRACE data and in-situ groundwater measurements from earlier report studies; whereas the seasonal hydrologic variation reflects human behavior of groundwater pumping for agriculture irrigation in spring, leading to less water storage in summer than that in the winter season. However, less than 20% of weighted root-mean-squared (WRMS) reductions were detected for all the selected GPS stations when GRACE-derived seasonal deformations were removed from detrended GPS height time series. This discrepancy is probably because the GRACE-derived seasonal signals are large-scale, while the GPS-derived signals are local point measurements. PMID:25340454

  11. Earth surface deformation in the North China Plain detected by joint analysis of GRACE and GPS data.

    Science.gov (United States)

    Liu, Renli; Li, Jiancheng; Fok, Hok Sum; Shum, C K; Li, Zhao

    2014-10-22

    Mass redistribution of the Earth causes variable loading that deforms the solid Earth. While most recent studies using geodetic techniques focus on regions (such as the Amazon basin and the Nepal Himalayas) with large seasonal deformation amplitudes on the order of 1-4 cm due to hydrologic loading, few such studies have been conducted on the regions where the seasonal deformation amplitude is half as large. Here, we use joint GPS and GRACE data to investigate the vertical deformation due to hydrologic loading in the North China Plain, where significant groundwater depletion has been reported. We found that the GPS- and GRACE-derived secular trends and seasonal signals are in good agreement, with an uplift magnitude of 1-2 mm/year and a correlation of 85.0%-98.5%, respectively. This uplift rate is consistent with groundwater depletion rate estimated from GRACE data and in-situ groundwater measurements from earlier report studies; whereas the seasonal hydrologic variation reflects human behavior of groundwater pumping for agriculture irrigation in spring, leading to less water storage in summer than that in the winter season. However, less than 20% of weighted root-mean-squared (WRMS) reductions were detected for all the selected GPS stations when GRACE-derived seasonal deformations were removed from detrended GPS height time series. This discrepancy is probably because the GRACE-derived seasonal signals are large-scale, while the GPS-derived signals are local point measurements.

  12. Evaluation of two transport aircraft and several ground test vehicle friction measurements obtained for various runway surface types and conditions. A summary of test results from joint FAA/NASA Runway Friction Program

    Science.gov (United States)

    Yager, Thomas J.; Vogler, William A.; Baldasare, Paul

    1990-01-01

    Tests with specially instrumented NASA Boeing 737 and 727 aircraft together with several different ground friction measuring devices were conducted for a variety of runway surface types and conditions. These tests are part of joint FAA/NASA Aircraft/Ground Vehicle Runway Friction Program aimed at obtaining a better understanding of aircraft ground handling performance under adverse weather conditions and defining relationships between aircraft and ground vehicle tire friction measurements. Aircraft braking performance on dry, wet, snow and ice-covered runway conditions is discussed as well as ground vehicle friction data obtained under similar runway conditions. For a given contaminated runway surface condition, the correlation between ground vehicles and aircraft friction data is identified. The influence of major test parameters on friction measurements such as speed, test tire characteristics, type and amount of surface contaminant, and ambient temperature are discussed. The effect of surface type on wet friction levels is also evaluated from comparative data collected on grooved and ungrooved concrete and asphalt surfaces.

  13. Assimilation of GRACE Terrestrial Water Storage into a Land Surface Model: Evaluation 1 and Potential Value for Drought Monitoring in Western and Central Europe

    Science.gov (United States)

    Li, Bailing; Rodell, Matthew; Zaitchik, Benjamin F.; Reichle, Rolf H.; Koster, Randal D.; van Dam, Tonie M.

    2012-01-01

    A land surface model s ability to simulate states (e.g., soil moisture) and fluxes (e.g., runoff) is limited by uncertainties in meteorological forcing and parameter inputs as well as inadequacies in model physics. In this study, anomalies of terrestrial water storage (TWS) observed by the Gravity Recovery and Climate Experiment (GRACE) satellite mission were assimilated into the NASA Catchment land surface model in western and central Europe for a 7-year period, using a previously developed ensemble Kalman smoother. GRACE data assimilation led to improved runoff correlations with gauge data in 17 out of 18 hydrological basins, even in basins smaller than the effective resolution of GRACE. Improvements in root zone soil moisture were less conclusive, partly due to the shortness of the in situ data record. In addition to improving temporal correlations, GRACE data assimilation also reduced increasing trends in simulated monthly TWS and runoff associated with increasing rates of precipitation. GRACE assimilated root zone soil moisture and TWS fields exhibited significant changes in their dryness rankings relative to those without data assimilation, suggesting that GRACE data assimilation could have a substantial impact on drought monitoring. Signals of drought in GRACE TWS correlated well with MODIS Normalized Difference Vegetation Index (NDVI) data in most areas. Although they detected the same droughts during warm seasons, drought signatures in GRACE derived TWS exhibited greater persistence than those in NDVI throughout all seasons, in part due to limitations associated with the seasonality of vegetation.

  14. Geochemical orientation survey of stream sediment, stream water, and ground water near uranium prospects, Monticello area, New York. National Uranium Resource Evaluation Program

    International Nuclear Information System (INIS)

    Rose, A.W.; Smith, A.T.; Wesolowski, D.

    1982-08-01

    A detailed geochemical test survey has been conducted in a 570 sq km area around six small copper-uranium prospects in sandstones of the Devonian Catskill Formation near Monticello in southern New York state. This report summarizes and interprets the data for about 500 stream sediment samples, 500 stream water samples, and 500 ground water samples, each analyzed for 40 to 50 elements. The groundwater samples furnish distinctive anomalies for uranium, helium, radon, and copper near the mineralized localities, but the samples must be segregated into aquifers in order to obtain continuous well-defined anomalies. Two zones of uranium-rich water (1 to 16 parts per billion) can be recognized on cross sections; the upper zone extends through the known occurrences. The anomalies in uranium and helium are strongest in the deeper parts of the aquifers and are diluted in samples from shallow wells. In stream water, copper and uranium are slightly anomalous, as in an ore factor derived from factor analysis. Ratios of copper, uranium, and zinc to conductivity improve the resolution of anomalies. In stream sediment, extractable uranium, copper, niobium, vanadium, and an ore factor furnish weak anomalies, and ratios of uranium and copper to zinc improve the definition of anomalies. The uranium/thorium ratio is not helpful. Published analyses of rock samples from the nearby stratigraphic section show distinct anomalies in the zone containing the copper-uranium occurrences. This report is being issued without the normal detailed technical and copy editing, to make the data available to the public before the end of the National Uranium Reconnaissance Evaluation program

  15. Geochemical orientation survey of stream sediment, stream water, and ground water near uranium prospects, Monticello area, New York. National Uranium Resource Evaluation Program

    Energy Technology Data Exchange (ETDEWEB)

    Rose, A. W.; Smith, A. T.; Wesolowski, D.

    1982-08-01

    A detailed geochemical test survey has been conducted in a 570 sq km area around six small copper-uranium prospects in sandstones of the Devonian Catskill Formation near Monticello in southern New York state. This report summarizes and interprets the data for about 500 stream sediment samples, 500 stream water samples, and 500 ground water samples, each analyzed for 40 to 50 elements. The groundwater samples furnish distinctive anomalies for uranium, helium, radon, and copper near the mineralized localities, but the samples must be segregated into aquifers in order to obtain continuous well-defined anomalies. Two zones of uranium-rich water (1 to 16 parts per billion) can be recognized on cross sections; the upper zone extends through the known occurrences. The anomalies in uranium and helium are strongest in the deeper parts of the aquifers and are diluted in samples from shallow wells. In stream water, copper and uranium are slightly anomalous, as in an ore factor derived from factor analysis. Ratios of copper, uranium, and zinc to conductivity improve the resolution of anomalies. In stream sediment, extractable uranium, copper, niobium, vanadium, and an ore factor furnish weak anomalies, and ratios of uranium and copper to zinc improve the definition of anomalies. The uranium/thorium ratio is not helpful. Published analyses of rock samples from the nearby stratigraphic section show distinct anomalies in the zone containing the copper-uranium occurrences. This report is being issued without the normal detailed technical and copy editing, to make the data available to the public before the end of the National Uranium Reconnaissance Evaluation program.

  16. The use of gravimetric data from GRACE mission in the understanding of polar motion variations

    Science.gov (United States)

    Seoane, L.; Nastula, J.; Bizouard, C.; Gambis, D.

    2009-08-01

    Tesseral coefficients C21 and S21 derived from Gravity Recovery and Climate Experiment (GRACE) observations allow to compute the mass term of the polar-motion excitation function. This independent estimation can improve the geophysical models and, in addition, determine the unmodelled phenomena. In this paper, we intend to validate the polar motion excitation derived from GRACE's last release (GRACE Release 4) computed by different institutes: GeoForschungsZentrum (GFZ), Postdam, Germany; Center for Space Research (CSR), Austin, USA; Jet Propulsion Laboratory (JPL), Pasadena, USA, and the Groupe de Recherche en Géodésie Spatiale (GRGS), Toulouse, France. For this purpose, we compare these excitations functions first to the mass term obtained from observed Earth's rotation variations free of the motion term and, second, to the mass term estimated from geophysical fluids models. We confirm the large improvement of the CSR solution, and we show that the GRGS estimate is also well correlated with the geodetic observations. Significant discrepancies exist between the solutions of each centre. The source of these differences is probably related to the data processing strategy. We also consider residuals computed after removing the geophysical models or the gravimetric solutions from the geodetic mass term. We show that the residual excitation based on models is smoother than the gravimetric data, which are still noisy. Still, they are comparable for the χ2 component. It appears that χ2 residual signals using GFZ and JPL data have less variability. Finally, for assessing the impact of the geophysical fluids models choice on our results, we checked two different oceanic excitation series. We show the significant differences in the residuals correlations, especially for the χ1 more sensitive to the oceanic signals.

  17. Assessing sequential data assimilation techniques for integrating GRACE data into a hydrological model

    KAUST Repository

    Khaki, M.

    2017-07-06

    The time-variable terrestrial water storage (TWS) products from the Gravity Recovery And Climate Experiment (GRACE) have been increasingly used in recent years to improve the simulation of hydrological models by applying data assimilation techniques. In this study, for the first time, we assess the performance of the most popular data assimilation sequential techniques for integrating GRACE TWS into the World-Wide Water Resources Assessment (W3RA) model. We implement and test stochastic and deterministic ensemble-based Kalman filters (EnKF), as well as Particle filters (PF) using two different resampling approaches of Multinomial Resampling and Systematic Resampling. These choices provide various opportunities for weighting observations and model simulations during the assimilation and also accounting for error distributions. Particularly, the deterministic EnKF is tested to avoid perturbing observations before assimilation (that is the case in an ordinary EnKF). Gaussian-based random updates in the EnKF approaches likely do not fully represent the statistical properties of the model simulations and TWS observations. Therefore, the fully non-Gaussian PF is also applied to estimate more realistic updates. Monthly GRACE TWS are assimilated into W3RA covering the entire Australia. To evaluate the filters performances and analyze their impact on model simulations, their estimates are validated by independent in-situ measurements. Our results indicate that all implemented filters improve the estimation of water storage simulations of W3RA. The best results are obtained using two versions of deterministic EnKF, i.e. the Square Root Analysis (SQRA) scheme and the Ensemble Square Root Filter (EnSRF), respectively improving the model groundwater estimations errors by 34% and 31% compared to a model run without assimilation. Applying the PF along with Systematic Resampling successfully decreases the model estimation error by 23%.

  18. The Impact of Atmospheric Modeling Errors on GRACE Estimates of Mass Loss in Greenland and Antarctica

    Science.gov (United States)

    Hardy, Ryan A.; Nerem, R. Steven; Wiese, David N.

    2017-12-01

    Systematic errors in Gravity Recovery and Climate Experiment (GRACE) monthly mass estimates over the Greenland and Antarctic ice sheets can originate from low-frequency biases in the European Centre for Medium-Range Weather Forecasts (ECMWF) Operational Analysis model, the atmospheric component of the Atmospheric and Ocean Dealising Level-1B (AOD1B) product used to forward model atmospheric and ocean gravity signals in GRACE processing. These biases are revealed in differences in surface pressure between the ECMWF Operational Analysis model, state-of-the-art reanalyses, and in situ surface pressure measurements. While some of these errors are attributable to well-understood discrete model changes and have published corrections, we examine errors these corrections do not address. We compare multiple models and in situ data in Antarctica and Greenland to determine which models have the most skill relative to monthly averages of the dealiasing model. We also evaluate linear combinations of these models and synthetic pressure fields generated from direct interpolation of pressure observations. These models consistently reveal drifts in the dealiasing model that cause the acceleration of Antarctica's mass loss between April 2002 and August 2016 to be underestimated by approximately 4 Gt yr-2. We find similar results after attempting to solve the inverse problem, recovering pressure biases directly from the GRACE Jet Propulsion Laboratory RL05.1 M mascon solutions. Over Greenland, we find a 2 Gt yr-1 bias in mass trend. While our analysis focuses on errors in Release 05 of AOD1B, we also evaluate the new AOD1B RL06 product. We find that this new product mitigates some of the aforementioned biases.

  19. Evaluating water storage variations in the MENA region using GRACE satellite data

    KAUST Repository

    Lopez, Oliver

    2013-12-01

    Terrestrial water storage (TWS) variations over large river basins can be derived from temporal gravity field variations observed by the Gravity Recovery and Climate Experiment (GRACE) satellites. These signals are useful for determining accurate estimates of water storage and fluxes over areas covering a minimum of 150,000 km2 (length scales of a few hundred kilometers) and thus prove to be a valuable tool for regional water resources management, particularly for areas with a lack of in-situ data availability or inconsistent monitoring, such as the Middle East and North Africa (MENA) region. This already stressed arid region is particularly vulnerable to climate change and overdraft of its non-renewable freshwater sources, and thus direction in managing its resources is a valuable aid. An inter-comparison of different GRACE-derived TWS products was done in order to provide a quantitative assessment on their uncertainty and their utility for diagnosing spatio-temporal variability in water storage over the MENA region. Different processing approaches for the inter-satellite tracking data from the GRACE mission have resulted in the development of TWS products, with resolutions in time from 10 days to 1 month and in space from 0.5 to 1 degree global gridded data, while some of them use input from land surface models in order to restore the original signal amplitudes. These processing differences and the difficulties in recovering the mass change signals over arid regions will be addressed. Output from the different products will be evaluated and compared over basins inside the MENA region, and compared to output from land surface models.

  20. Water storage changes in North America retrieved from GRACE gravity and GPS data

    Directory of Open Access Journals (Sweden)

    Hansheng Wang

    2015-07-01

    Full Text Available As global warming continues, the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management. In North America as elsewhere in the world, changes in water resources strongly impact agriculture and animal husbandry. From a combination of Gravity Recovery and Climate Experiment (GRACE gravity and Global Positioning System (GPS data, it is recently found that water storage from August, 2002 to March, 2011 recovered after the extreme Canadian Prairies drought between 1999 and 2005. In this paper, we use GRACE monthly gravity data of Release 5 to track the water storage change from August, 2002 to June, 2014. In Canadian Prairies and the Great Lakes areas, the total water storage is found to have increased during the last decade by a rate of 73.8 ± 14.5 Gt/a, which is larger than that found in the previous study due to the longer time span of GRACE observations used and the reduction of the leakage error. We also find a long term decrease of water storage at a rate of −12.0 ± 4.2 Gt/a in Ungava Peninsula, possibly due to permafrost degradation and less snow accumulation during the winter in the region. In addition, the effect of total mass gain in the surveyed area, on present-day sea level, amounts to −0.18 mm/a, and thus should be taken into account in studies of global sea level change.

  1. Evaluating Water Storage Variations in the MENA region using GRACE Satellite Data

    Science.gov (United States)

    Lopez, O.; Houborg, R.; McCabe, M. F.

    2013-12-01

    Terrestrial water storage (TWS) variations over large river basins can be derived from temporal gravity field variations observed by the Gravity Recovery and Climate Experiment (GRACE) satellites. These signals are useful for determining accurate estimates of water storage and fluxes over areas covering a minimum of 150,000 km2 (length scales of a few hundred kilometers) and thus prove to be a valuable tool for regional water resources management, particularly for areas with a lack of in-situ data availability or inconsistent monitoring, such as the Middle East and North Africa (MENA) region. This already stressed arid region is particularly vulnerable to climate change and overdraft of its non-renewable freshwater sources, and thus direction in managing its resources is a valuable aid. An inter-comparison of different GRACE-derived TWS products was done in order to provide a quantitative assessment on their uncertainty and their utility for diagnosing spatio-temporal variability in water storage over the MENA region. Different processing approaches for the inter-satellite tracking data from the GRACE mission have resulted in the development of TWS products, with resolutions in time from 10 days to 1 month and in space from 0.5 to 1 degree global gridded data, while some of them use input from land surface models in order to restore the original signal amplitudes. These processing differences and the difficulties in recovering the mass change signals over arid regions will be addressed. Output from the different products will be evaluated and compared over basins inside the MENA region, and compared to output from land surface models.

  2. Ground Pollution Science

    International Nuclear Information System (INIS)

    Oh, Jong Min; Bae, Jae Geun

    1997-08-01

    This book deals with ground pollution science and soil science, classification of soil and fundamentals, ground pollution and human, ground pollution and organic matter, ground pollution and city environment, environmental problems of the earth and ground pollution, soil pollution and development of geological features of the ground, ground pollution and landfill of waste, case of measurement of ground pollution.

  3. Improved regional sea-level estimates from Ice Sheets, Glaciers and land water storage using GRACE time series and other data

    Science.gov (United States)

    He, Z.; Velicogna, I.; Hsu, C. W.; Rignot, E. J.; Mouginot, J.; Scheuchl, B.; Fettweis, X.; van den Broeke, M. R.

    2017-12-01

    Changes in ice sheets, glaciers and ice caps (GIC) and land water mass cause regional sea level variations that differ significantly from a uniform re-distribution of mass over the ocean, with a decrease in sea level compared to the global mean sea level contribution (GMSL) near the sources of mass added to the ocean and an increase up to 30% larger than the GMSL in the far field. The corresponding sea level fingerprints (SLF) are difficult to separate from ocean dynamics on short time and spatial scales but as ice melt continues, the SLF signal will become increasingly dominant in the pattern of regional sea level rise. It has been anticipated that it will be another few decades before the land ice SLF could be identified in the pattern of regional sea level rise. Here, we combine 40 years of observations of ice sheet mass balance for Antarctica (1975-present) and Greenland (1978-present), along with surface mass balance reconstructions of glacier and ice caps mass balance (GIC) from 1970s to present to determine the contribution to the SLF from melting land ice (MAR and RACMO). We compare the results with observations from GRACE for the time period 2002 to present for evaluation of our approach. Land hydrology is constrained by GRACE data for the period 2002-present and by the GLDAS-NOAH land hydrology model for the longer time period. Over the long time period, we find that the contribution from land ice dominates. We quantify the contribution to the total SLF from Greenland and Antarctica in various parts of the world over the past 40 years. More important, we compare the cumulative signal from SLF with tide gauge records around the world, corrected for earth dynamics, to determine whether the land ice SLF can be detected in that record. Early results will be reported at the meeting. This work was performed at UC Irvine and at Caltech's Jet Propulsion Laboratory under a contract with NASA's Cryospheric Science Program.

  4. Regionally Optimized GRACE Processing and Inter-comparison on the Antarctic Ice Sheet

    Science.gov (United States)

    Mohajerani, Y.; Velicogna, I.; Sutterley, T. C.; Rignot, E. J.

    2017-12-01

    The Antarctic ice sheet is losing mass at an accelerating rate, with a sea level contribution that changed from 0.08mm/yr from 1992 to 2001 to 0.4mm/yr from 2002 to 2011. While most of this contribution comes from West Antarctica, Totten Glacier has the largest discharge of ice in East Antarctica, with a sea level rise potential of 3.9 m. Furthermore, the drainage basin of Totten Glacier, along the neighboring Moscow University Glacier are below sea level, extending hundreds of kilometers inland. Therefore, obtaining regional estimates of both western and eastern Antarctic basins are of critical importance. The GRACE (Gravity Recovery and Climate Experiment) satellite has been providing mass balance time-series from geoid changes since 2002. Several mascon and harmonic GRACE solutions are available from different processing centers. Here, we evaluate the various solutions across the ice sheet and a new set of regionally optimized mascons to study the mass balance of Totten and Moscow University glaciers. We obtain a trend of -16.5±4.1Gt/yr with an acceleration of -2.0±1.8Gt/yr2 for the two glaciers for the period April 2002 to December 2016 using the Ivins et al (2013) GIA model (errors include leakage, GIA, and regression errors). We compare the results with the Mass Budget Method that combines ice discharge (D) and surface mass balance (SMB) from two models: 1) RACMO2.3, and 2) MAR3.6.4. MBM/RACMO2.3 shows the best agreement with the GRACE estimates. Within the common period from April 2002 to December 2015, the MBM/RACMO2.3 and MAR3.6.4 results are -15.6±1.8Gt/yr and -6.7±1.5Gt/yr respectively, while the GRACE time-series has a trend of -14.8±2.7 Gt/yr. We extend the study to the Getz Ice Shelf, the third largest ice shelf in West Antarctica after Ronne and Ross West ice shelves. We compare our gravity-derived mass estimates, the mass budget estimates, and the volume changes from altimetry data to compare the estimates and obtain a multi-sensor assessment

  5. GRACE-based estimates of water discharge over the Yellow River basin

    Directory of Open Access Journals (Sweden)

    Qiong Li

    2016-05-01

    Full Text Available As critical component of hydrologic cycle, basin discharge is a key issue for understanding the hydrological and climatologic related to water and energy cycles. Combining GRACE gravity field models with ET from GLDAS models and precipitation from GPCP, discharge of the Yellow River basin are estimated from the water balance equation. While comparing the results with discharge from GLDAS model and in situ measurements, the results reveal that discharge from Mosaic and CLM GLDAS model can partially represent the river discharge and the discharge estimation from water balance equation could reflect the discharge from precipitation over the Yellow River basin.

  6. Faith and grace in the thought of Tanabe Hajime and of Søren Kierkegaard

    OpenAIRE

    Henneberg, Peter

    2010-01-01

    The subject matter of this essay is to compare the conceptions which Søren Kierkegaard and Tanabe Hajime have of the notions of religious faith and of divine grace. The investigation was triggered by the observation that Tanabe’s philosophy owes much to the thought of Kierkegaard, and by the fact that Kierkegaard has been trained as a Danish Protestant theologian while Tanabe adopted for himself positions of Japanese Pure Land Buddhism. After a rigorous analysis of the notions of faith and...

  7. High resolution time-lapse gravity field from GRACE for hydrological modelling

    DEFF Research Database (Denmark)

    Krogh, Pernille Engelbredt

    Calibration of large scale hydrological models have traditionally been performed using point observations, which are often sparsely distributed. The Gravity Recovery And Climate Experiment (GRACE) mission provides global remote sensing information about mass fluxes with unprecedented accuracy...... than for the mascon only solution, but later than the GLDAS/Noah TWS and the CNES/GRGS SH solutions. The deviations are 10–20 days. From this point of view, the tuning of hydrological models with KBRR data is certainly feasible, though highly time consuming and complicated at the moment. The method...

  8. Improvement of the GRACE star camera data based on the revision of the combination method

    Science.gov (United States)

    Bandikova, Tamara; Flury, Jakob

    2014-11-01

    The new release of the sensor and instrument data (Level-1B release 02) of the Gravity Recovery and Climate Experiment (GRACE) had a substantial impact on the improvement of the overall accuracy of the gravity field models. This has implied that improvements on the sensor data level can still significantly contribute to arriving closer to the GRACE baseline accuracy. The recent analysis of the GRACE star camera data (SCA1B RL02) revealed their unexpectedly higher noise. As the star camera (SCA) data are essential for the processing of the K-band ranging data and the accelerometer data, thorough investigation of the data set was needed. We fully reexamined the SCA data processing from Level-1A to Level-1B with focus on the combination method of the data delivered by the two SCA heads. In the first step, we produced and compared our own combined attitude solution by applying two different combination methods on the SCA Level-1A data. The first method introduces the information about the anisotropic accuracy of the star camera measurement in terms of a weighing matrix. This method was applied in the official processing as well. The alternative method merges only the well determined SCA boresight directions. This method was implemented on the GRACE SCA data for the first time. Both methods were expected to provide optimal solution characteristic by the full accuracy about all three axes, which was confirmed. In the second step, we analyzed the differences between the official SCA1B RL02 data generated by the Jet Propulsion Laboratory (JPL) and our solution. SCA1B RL02 contains systematically higher noise of about a factor 3-4. The data analysis revealed that the reason is the incorrect implementation of algorithms in the JPL processing routines. After correct implementation of the combination method, significant improvement within the whole spectrum was achieved. Based on these results, the official reprocessing of the SCA data is suggested, as the SCA attitude data

  9. Greenland inland ice melt-off: Analysis of global gravity data from the GRACE satellites

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Andersen, Ole Baltazar; Svendsen, Peter L.

    2011-01-01

    This paper gives an introductory analysis of gravity data from the GRACE (Gravity Recovery And Climate Experiment) twin satellites. The data consist of gravity data in the form of 10-day maximum values of 1◦ by 1◦ equivalent water height (EWH) in meters starting at 29 July 2002 and ending at 25...... August 2010. Results focussing on Greenland show statistically significant mass loss interpreted as inland ice melt-off to the SE and NW with an acceleration in the melt-off occurring to the NW and a possible deceleration to the SE. Also, there are strong indications of a transition taking place...

  10. La dialectique du nouveau et du même dans God's Grace de Bernard Malamud

    OpenAIRE

    Chard-Hutchinson, Martine

    2017-01-01

    What's the use avoiding rats and horror, hiding from Cops and dentists' drills ? Somebody will invent Buchenwald next door. Alan Ginzberg "If it's all right with you," he addressed the gorilla in gratitude, "I'd like to call you George after my late wife's father, who was an accomplished dentist, a wonderful man. He often fixed people's teeth for nothing." Bernard Malamud God's Grace, le dernier roman achevé de Bernard Malamud, est une histoire "pleine de fureur et de bruit" qui se présente ...

  11. Monthly gravity field recovery from GRACE orbits and K-band measurements using variational equations approach

    Directory of Open Access Journals (Sweden)

    Changqing Wang

    2015-07-01

    Full Text Available The Gravity Recovery and Climate Experiment (GRACE mission can significantly improve our knowledge of the temporal variability of the Earth's gravity field. We obtained monthly gravity field solutions based on variational equations approach from GPS-derived positions of GRACE satellites and K-band range-rate measurements. The impact of different fixed data weighting ratios in temporal gravity field recovery while combining the two types of data was investigated for the purpose of deriving the best combined solution. The monthly gravity field solution obtained through above procedures was named as the Institute of Geodesy and Geophysics (IGG temporal gravity field models. IGG temporal gravity field models were compared with GRACE Release05 (RL05 products in following aspects: (i the trend of the mass anomaly in China and its nearby regions within 2005–2010; (ii the root mean squares of the global mass anomaly during 2005–2010; (iii time-series changes in the mean water storage in the region of the Amazon Basin and the Sahara Desert between 2005 and 2010. The results showed that IGG solutions were almost consistent with GRACE RL05 products in above aspects (i–(iii. Changes in the annual amplitude of mean water storage in the Amazon Basin were 14.7 ± 1.2 cm for IGG, 17.1 ± 1.3 cm for the Centre for Space Research (CSR, 16.4 ± 0.9 cm for the GeoForschungsZentrum (GFZ and 16.9 ± 1.2 cm for the Jet Propulsion Laboratory (JPL in terms of equivalent water height (EWH, respectively. The root mean squares of the mean mass anomaly in Sahara were 1.2 cm, 0.9 cm, 0.9 cm and 1.2 cm for temporal gravity field models of IGG, CSR, GFZ and JPL, respectively. Comparison suggested that IGG temporal gravity field solutions were at the same accuracy level with the latest temporal gravity field solutions published by CSR, GFZ and JPL.

  12. "Tugboat Annie:" nursing's hero of Pearl Harbor--Grace Lally (1897-1983).

    Science.gov (United States)

    Hawkins, J W; Matthews, I

    1991-01-01

    In 1991 we will mark the 50th anniversary of the Japanese attack on Pearl Harbor. Few nurses know that the Chief Nurse aboard the USS Solace, the only hospital ship in port on that fateful day, played a critical role in caring for the survivors. Grace Lally's calm, professional manner, along with her sensitivity to the needs of her patients, her 12 nurses, and the crew of the Solace made her a hero. This study is an investigation of her role on December 7, 1941, and her contributions as a career military nurse.

  13. Pascal’s Wager and the dispute about the nature of Grace

    Directory of Open Access Journals (Sweden)

    Lech Gruszecki

    2017-07-01

    Full Text Available Pascal’s Wager is one of the most interesting and original arguments for the existence of God. It does not invoke advanced metaphysical concepts; instead, it employs the methods and concepts of probability calculus. Its argumentative power mainly rests on the appropriate interpretation of the determinants of human existence, which are taken to include our cognitive, moral and physical limitations. The article discusses different aspects of Pascal’s reasoning. In particular, it examines the wager in the context of Grace as something that Pascal himself believed in.

  14. GRACE Gravity Satellite Observations of Terrestrial Water Storage Changes for Drought Characterization in the Arid Land of Northwestern China

    Directory of Open Access Journals (Sweden)

    Yanping Cao

    2015-01-01

    Full Text Available Drought is a complex natural hazard which can have negative effects on agriculture, economy, and human life. In this paper, the primary goal is to explore the application of the Gravity Recovery and Climate Experiment (GRACE gravity satellite data for the quantitative investigation of the recent drought dynamic over the arid land of northwestern China, a region with scarce hydrological and meteorological observation datasets. The spatiotemporal characteristics of terrestrial water storage changes (TWSC were first evaluated based on the GRACE satellite data, and then validated against hydrological model simulations and precipitation data. A drought index, the total storage deficit index (TSDI, was derived on the basis of GRACE-recovered TWSC. The spatiotemporal distributions of drought events from 2003 to 2012 in the study region were obtained using the GRACE-derived TSDI. Results derived from TSDI time series indicated that, apart from four short-term (three months drought events, the study region experienced a severe long-term drought from May 2008 to December 2009. As shown in the spatial distribution of TSDI-derived drought conditions, this long-term drought mainly concentrated in the northwestern area of the entire region, where the terrestrial water storage was in heavy deficit. These drought characteristics, which were detected by TSDI, were consistent with local news reports and other researchers’ results. Furthermore, a comparison between TSDI and Standardized Precipitation Index (SPI implied that GRACE TSDI was a more reliable integrated drought indicator (monitoring agricultural and hydrological drought in terms of considering total terrestrial water storages for large regions. The GRACE-derived TSDI can therefore be used to characterize and monitor large-scale droughts in the arid regions, being of special value for areas with scarce observations.

  15. An Improved GRACE Terrestrial Water Storage Assimilation System For Estimating Large-Scale Soil Moisture and Shallow Groundwater

    Science.gov (United States)

    Girotto, M.; De Lannoy, G. J. M.; Reichle, R. H.; Rodell, M.

    2015-12-01

    The Gravity Recovery And Climate Experiment (GRACE) mission is unique because it provides highly accurate column integrated estimates of terrestrial water storage (TWS) variations. Major limitations of GRACE-based TWS observations are related to their monthly temporal and coarse spatial resolution (around 330 km at the equator), and to the vertical integration of the water storage components. These challenges can be addressed through data assimilation. To date, it is still not obvious how best to assimilate GRACE-TWS observations into a land surface model, in order to improve hydrological variables, and many details have yet to be worked out. This presentation discusses specific recent features of the assimilation of gridded GRACE-TWS data into the NASA Goddard Earth Observing System (GEOS-5) Catchment land surface model to improve soil moisture and shallow groundwater estimates at the continental scale. The major recent advancements introduced by the presented work with respect to earlier systems include: 1) the assimilation of gridded GRACE-TWS data product with scaling factors that are specifically derived for data assimilation purposes only; 2) the assimilation is performed through a 3D assimilation scheme, in which reasonable spatial and temporal error standard deviations and correlations are exploited; 3) the analysis step uses an optimized calculation and application of the analysis increments; 4) a poor-man's adaptive estimation of a spatially variable measurement error. This work shows that even if they are characterized by a coarse spatial and temporal resolution, the observed column integrated GRACE-TWS data have potential for improving our understanding of soil moisture and shallow groundwater variations.

  16. Downscaling GRACE Remote Sensing Datasets to High-Resolution Groundwater Storage Change Maps of California’s Central Valley

    Directory of Open Access Journals (Sweden)

    Michelle E. Miro

    2018-01-01

    Full Text Available NASA’s Gravity Recovery and Climate Experiment (GRACE has already proven to be a powerful data source for regional groundwater assessments in many areas around the world. However, the applicability of GRACE data products to more localized studies and their utility to water management authorities have been constrained by their limited spatial resolution (~200,000 km2. Researchers have begun to address these shortcomings with data assimilation approaches that integrate GRACE-derived total water storage estimates into complex regional models, producing higher-resolution estimates of hydrologic variables (~2500 km2. Here we take those approaches one step further by developing an empirically based model capable of downscaling GRACE data to a high-resolution (~16 km2 dataset of groundwater storage changes over a portion of California’s Central Valley. The model utilizes an artificial neural network to generate a series of high-resolution maps of groundwater storage change from 2002 to 2010 using GRACE estimates of variations in total water storage and a series of widely available hydrologic variables (PRISM precipitation and temperature data, digital elevation model (DEM-derived slope, and Natural Resources Conservation Service (NRCS soil type. The neural network downscaling model is able to accurately reproduce local groundwater behavior, with acceptable Nash-Sutcliffe efficiency (NSE values for calibration and validation (ranging from 0.2445 to 0.9577 and 0.0391 to 0.7511, respectively. Ultimately, the model generates maps of local groundwater storage change at a 100-fold higher resolution than GRACE gridded data products without the use of computationally intensive physical models. The model’s simulated maps have the potential for application to local groundwater management initiatives in the region.

  17. Reconciling ocean mass content change based on direct and inverse approaches by utilizing data from GRACE, altimetry and Swarm

    Science.gov (United States)

    Rietbroek, R.; Uebbing, B.; Lück, C.; Kusche, J.

    2017-12-01

    Ocean mass content (OMC) change due to the melting of the ice-sheets in Greenland and Antarctica, melting of glaciers and changes in terrestrial hydrology is a major contributor to present-day sea level rise. Since 2002, the GRACE satellite mission serves as a valuable tool for directly measuring the variations in OMC. As GRACE has almost reached the end of its lifetime, efforts are being made to utilize the Swarm mission for the recovery of low degree time-variable gravity fields to bridge a possible gap until the GRACE-FO mission and to fill up periods where GRACE data was not existent. To this end we compute Swarm monthly normal equations and spherical harmonics that are found competitive to other solutions. In addition to directly measuring the OMC, combination of GRACE gravity data with altimetry data in a global inversion approach allows to separate the total sea level change into individual mass-driven and steric contributions. However, published estimates of OMC from the direct and inverse methods differ not only depending on the time window, but also are influenced by numerous post-processing choices. Here, we will look into sources of such differences between direct and inverse approaches and evaluate the capabilities of Swarm to derive OMC. Deriving time series of OMC requires several processing steps; choosing a GRACE (and altimetry) product, data coverage, masks and filters to be applied in either spatial or spectral domain, corrections related to spatial leakage, GIA and geocenter motion. In this study, we compare and quantify the effects of the different processing choices of the direct and inverse methods. Our preliminary results point to the GIA correction as the major source of difference between the two approaches.

  18. Can mountain glacier melting explains the GRACE-observed mass loss in the southeast Tibetan Plateau: From a climate perspective?

    Science.gov (United States)

    Song, Chunqiao; Ke, Linghong; Huang, Bo; Richards, Keith S.

    2015-01-01

    The southeast Tibetan Plateau (SETP) includes the majority of monsoonal temperate glaciers in High Mountain Asia (HMA), which is an important source of water for the upper reaches of several large Asian river systems. Climatic change and variability has substantial impacts on cryosphere and hydrological processes in the SETP. The Gravity Recovery and Climate Experiment (GRACE) gravimetry observations between 2003 and 2009 suggest that there was an average mass loss rate of - 5.99 ± 2.78 Gigatonnes (Gt)/yr in this region. Meanwhile, the hydrological data by model calculations from the GLDAS/Noah and CPC are used to estimate terrestrial water storage (TWS) changes with a slight negative trend of about - 0.3 Gt/yr. The recent studies (Kääb et al., 2012; Gardner et al., 2013) reported the thinning rates of mountain glaciers in HMA based on the satellite laser altimetry, and an approximate estimation of the glacier mass budget in the SETP was 4.69 ± 2.03 Gt/yr during 2003-2009. This estimate accounted for a large proportion ( 78.3%) of the difference between the GRACE TWS and model-calculated TWS changes. To better understand the cause of sharp mass loss existing in the SETP, the correlations between key climatic variables (precipitation and temperature) and the GRACE TWS changes are examined at different timescales between 2003 and 2011. The results show that precipitation is the leading factors of abrupt, seasonal and multi-year undulating signals of GRACE TWS anomaly time series, but with weak correlations with the inter-annual trend and annual mass budget of GRACE TWS. In contrast, the annual mean temperature is tightly associated with the annual net mass budget (r = 0.81, p < 0.01), which indirectly suggests that the GRACE-observed mass loss in the SETP may be highly related to glacial processes.

  19. Application of EOF/PCA-based methods in the post-processing of GRACE derived water variations

    Science.gov (United States)

    Forootan, Ehsan; Kusche, Jürgen

    2010-05-01

    Two problems that users of monthly GRACE gravity field solutions face are 1) the presence of correlated noise in the Stokes coefficients that increases with harmonic degree and causes ‘striping', and 2) the fact that different physical signals are overlaid and difficult to separate from each other in the data. These problems are termed the signal-noise separation problem and the signal-signal separation problem. Methods that are based on principal component analysis and empirical orthogonal functions (PCA/EOF) have been frequently proposed to deal with these problems for GRACE. However, different strategies have been applied to different (spatial: global/regional, spectral: global/order-wise, geoid/equivalent water height) representations of the GRACE level 2 data products, leading to differing results and a general feeling that PCA/EOF-based methods are to be applied ‘with care'. In addition, it is known that conventional EOF/PCA methods force separated modes to be orthogonal, and that, on the other hand, to either EOFs or PCs an arbitrary orthogonal rotation can be applied. The aim of this paper is to provide a common theoretical framework and to study the application of PCA/EOF-based methods as a signal separation tool due to post-process GRACE data products. In order to investigate and illustrate the applicability of PCA/EOF-based methods, we have employed them on GRACE level 2 monthly solutions based on the Center for Space Research, University of Texas (CSR/UT) RL04 products and on the ITG-GRACE03 solutions from the University of Bonn, and on various representations of them. Our results show that EOF modes do reveal the dominating annual, semiannual and also long-periodic signals in the global water storage variations, but they also show how choosing different strategies changes the outcome and may lead to unexpected results.

  20. Use of GRACE Terrestrial Water Storage Retrievals to Evaluate Model Estimates by the Australian Water Resources Assessment System

    Science.gov (United States)

    van Dijk, A. I. J. M.; Renzullo, L. J.; Rodell, M.

    2011-01-01

    Terrestrial water storage (TWS) estimates retrievals from the Gravity Recovery and Climate Experiment (GRACE) satellite mission were compared to TWS modeled by the Australian Water Resources Assessment (AWRA) system. The aim was to test whether differences could be attributed and used to identify model deficiencies. Data for 2003 2010 were decomposed into the seasonal cycle, linear trends and the remaining de-trended anomalies before comparing. AWRA tended to have smaller seasonal amplitude than GRACE. GRACE showed a strong (greater than 15 millimeter per year) drying trend in northwest Australia that was associated with a preceding period of unusually wet conditions, whereas weaker drying trends in the southern Murray Basin and southwest Western Australia were associated with relatively dry conditions. AWRA estimated trends were less negative for these regions, while a more positive trend was estimated for areas affected by cyclone Charlotte in 2009. For 2003-2009, a decrease of 7-8 millimeter per year (50-60 cubic kilometers per year) was estimated from GRACE, enough to explain 6-7% of the contemporary rate of global sea level rise. This trend was not reproduced by the model. Agreement between model and data suggested that the GRACE retrieval error estimates are biased high. A scaling coefficient applied to GRACE TWS to reduce the effect of signal leakage appeared to degrade quantitative agreement for some regions. Model aspects identified for improvement included a need for better estimation of rainfall in northwest Australia, and more sophisticated treatment of diffuse groundwater discharge processes and surface-groundwater connectivity for some regions.

  1. Characterization of spatio-temporal patterns for various GRACE- and GLDAS-born estimates for changes of global terrestrial water storage

    Science.gov (United States)

    Yang, Tao; Wang, Chao; Yu, Zhongbo; Xu, Feng

    2013-10-01

    Since the launch in March 2002, the Gravity Recovery and Climate Experiment (GRACE) satellite mission has provided us with a new method to estimate terrestrial water storage (TWS) variations by measuring earth gravity change with unprecedented accuracy. Thus far, a number of standardized GRACE-born TWS products are published by different international research teams. However, no characterization of spatio-temporal patterns for different GRACE hydrology products from the global perspective could be found. It is still a big challenge for the science community to identify the reliable global measurement of TWS anomalies due to our limited knowledge on the true value. Hence, it is urgently necessary to evaluate the uncertainty for various global estimates of the GRACE-born TWS changes by a number of international research organizations. Toward this end, this article presents an in-depth analysis for various GRACE-born and GLDAS-based estimates for changes of global terrestrial water storage. The work characterizes the inter-annual and intra-annual variability, probability density variations, and spatial patterns among different GRACE-born TWS estimates over six major continents, and compares them with results from GLDAS simulations. The underlying causes of inconsistency between GRACE- and GLDAS-born TWS estimates are thoroughly analyzed with an aim to improve our current knowledge in monitoring global TWS change. With a comprehensive consideration of the advantages and disadvantages among GRACE- and GLDAS-born TWS anomalies, a summary is thereafter recommended as a rapid reference for scientists, end-users, and policy-makers in the practices of global TWS change research. To our best knowledge, this work is the first attempt to characterize difference and uncertainty among various GRACE-born terrestrial water storage changes over the major continents estimated by a number of international research organizations. The results can provide beneficial reference to usage of

  2. Homocysteine enhances the predictive value of the GRACE risk score in patients with ST-elevation myocardial infarction.

    Science.gov (United States)

    Fan, Yan; Wang, Jianjun; Zhang, Sumei; Wan, Zhaofei; Zhou, Dong; Ding, Yanhong; He, Qinli; Xie, Ping

    2017-09-01

    The present study aims to investigate whether the addition of homocysteine level to the Global Registry of Acute Coronary Events (GRACE) risk score enhances its predictive value for clinical outcomes in ST-elevation myocardial infarction (STEMI). A total of 1143 consecutive patients with STEMI were included in this prospective cohort study. Homocysteine was detected, and the GRACE score was calculated. The predictive power of the GRACE score alone or combined with homocysteine was assessed by the receiver operating characteristic (ROC) analysis, methods of net reclassification improvement (NRI) and integrated discrimination improvement (IDI). During a median follow-up period of 36.7 months, 271 (23.7%) patients reached the clinical endpoints. It showed that the GRACE score and homocysteine could independently predict all-cause death [GRACE: HR=1.031 (1.024-1.039), p<0.001; homocysteine: HR=1.023 (1.018-1.028), p<0.001] and MACE [GRACE: HR=1.008 (1.005-1.011), p<0.001; homocysteine: HR=1.022 (1.018-1.025), p<0.001]. When they were used in combination to assess the clinical outcomes, the area under the ROC curve significantly increased from 0.786 to 0.884 (95% CI=0.067-0.128, Z=6.307, p<0.001) for all-cause death and from 0.678 to 0.759 (95% CI=0.055-0.108, Z=5.943, p<0.001) for MACE. The addition of homocysteine to the GRACE model improved NRI (all-cause death: 0.575, p<0.001; MACE: 0.621, p=0.008) and IDI (all-cause death: 0.083, p<0.001; MACE: 0.130, p=0.016), indicating effective discrimination and reclassification. Both the GRACE score and homocysteine are significant and independent predictors for clinical outcomes in patients with STEMI. A combination of them can develop a more predominant prediction for clinical outcomes in these patients.

  3. Communication grounding facility

    International Nuclear Information System (INIS)

    Lee, Gye Seong

    1998-06-01

    It is about communication grounding facility, which is made up twelve chapters. It includes general grounding with purpose, materials thermal insulating material, construction of grounding, super strength grounding method, grounding facility with grounding way and building of insulating, switched grounding with No. 1A and LCR, grounding facility of transmission line, wireless facility grounding, grounding facility in wireless base station, grounding of power facility, grounding low-tenton interior power wire, communication facility of railroad, install of arrester in apartment and house, install of arrester on introduction and earth conductivity and measurement with introduction and grounding resistance.

  4. On the capability of Swarm for surface mass variation monitoring: Quantitative assessment based on orbit information from CHAMP, GRACE and GOCE

    Science.gov (United States)

    Baur, Oliver; Weigelt, Matthias; Zehentner, Norbert; Mayer-Gürr, Torsten; Jäggi, Adrian

    2014-05-01

    In the last decade, temporal variations of the gravity field from GRACE observations have become one of the most ubiquitous and valuable sources of information for geophysical and environmental studies. In the context of global climate change, mass balance of the Arctic and Antarctic ice sheets gained particular attention. Because GRACE has outlived its predicted lifetime by several years already, it is very likely that a gap between GRACE and its successor GRACE follow-on (supposed to be launched in 2017, at the earliest) occurs. The Swarm mission - launched on November 22, 2013 - is the most promising candidate to bridge this potential gap, i.e., to directly acquire large-scale mass variation information on the Earth's surface in case of a gap between the present GRACE and the upcoming GRACE follow-on projects. Although the magnetometry mission Swarm has not been designed for gravity field purposes, its three satellites have the characteristics for such an endeavor: (i) low, near-circular and near-polar orbits, (ii) precise positioning with high-quality GNSS receivers, (iii) on-board accelerometers to measure the influence of non-gravitational forces. Hence, from an orbit analysis point of view the Swarm satellites are comparable to the CHAMP, GRACE and GOCE spacecraft. Indeed and as data analysis from CHAMP has been shown, the detection of annual signals and trends from orbit analysis is possible for long-wavelength features of the gravity field, although the accuracy associated with the inter-satellite GRACE measurements cannot be reached. We assess the capability of the (non-dedicated) mission Swarm for mass variation detection in a real-case environment (opposed to simulation studies). For this purpose, we "approximate" the Swarm scenario by the GRACE+CHAMP and GRACE+GOCE constellations. In a first step, kinematic orbits of the individual satellites are derived from GNSS observations. From these orbits, we compute monthly combined GRACE+CHAMP and GRACE

  5. Incorporation of GRACE Data into a Bayesian Model for Groundwater Drought Monitoring

    Science.gov (United States)

    Slinski, K.; Hogue, T. S.; McCray, J. E.; Porter, A.

    2015-12-01

    Groundwater drought, defined as the sustained occurrence of below average availability of groundwater, is marked by below average water levels in aquifers and reduced flows to groundwater-fed rivers and wetlands. The impact of groundwater drought on ecosystems, agriculture, municipal water supply, and the energy sector is an increasingly important global issue. However, current drought monitors heavily rely on precipitation and vegetative stress indices to characterize the timing, duration, and severity of drought events. The paucity of in situ observations of aquifer levels is a substantial obstacle to the development of systems to monitor groundwater drought in drought-prone areas, particularly in developing countries. Observations from the NASA/German Space Agency's Gravity Recovery and Climate Experiment (GRACE) have been used to estimate changes in groundwater storage over areas with sparse point measurements. This study incorporates GRACE total water storage observations into a Bayesian framework to assess the performance of a probabilistic model for monitoring groundwater drought based on remote sensing data. Overall, it is hoped that these methods will improve global drought preparedness and risk reduction by providing information on groundwater drought necessary to manage its impacts on ecosystems, as well as on the agricultural, municipal, and energy sectors.

  6. Results and Error Estimates from GRACE Forward Modeling over Greenland, Canada, and Alaska

    Science.gov (United States)

    Bonin, J. A.; Chambers, D. P.

    2012-12-01

    Forward modeling using a weighted least squares technique allows GRACE information to be projected onto a pre-determined collection of local basins. This decreases the impact of spatial leakage, allowing estimates of mass change to be better localized. The technique is especially valuable where models of current-day mass change are poor, such as over Greenland and Antarctica. However, the accuracy of the forward model technique has not been determined, nor is it known how the distribution of the local basins affects the results. We use a "truth" model composed of hydrology and ice-melt slopes as an example case, to estimate the uncertainties of this forward modeling method and expose those design parameters which may result in an incorrect high-resolution mass distribution. We then apply these optimal parameters in a forward model estimate created from RL05 GRACE data. We compare the resulting mass slopes with the expected systematic errors from the simulation, as well as GIA and basic trend-fitting uncertainties. We also consider whether specific regions (such as Ellesmere Island and Baffin Island) can be estimated reliably using our optimal basin layout.

  7. Evaluation of Release-05 GRACE time-variable gravity coefficients over the ocean

    Directory of Open Access Journals (Sweden)

    D. P. Chambers

    2012-10-01

    Full Text Available The latest release of GRACE (Gravity Recovery and Climate Experiment gravity field coefficients (Release-05, or RL05 are evaluated for ocean applications. Data have been processed using the current methodology for Release-04 (RL04 coefficients, and have been compared to output from two different ocean models. Results indicate that RL05 data from the three Science Data Centers – the Center for Space Research (CSR, GeoForschungsZentrum (GFZ, and Jet Propulsion Laboratory (JPL – are more consistent among themselves than the previous RL04 data. Moreover, the variance of residuals with the output of an ocean model is 50–60% lower for RL05 data than for RL04 data. A more optimized destriping algorithm is also tested, which improves the results slightly. By comparing the GRACE maps with two different ocean models, we can better estimate the uncertainty in the RL05 maps. We find the standard error to be about 1 cm (equivalent water thickness in the low- and mid-latitudes, and between 1.5 and 2 cm in the polar and subpolar oceans, which is comparable to estimated uncertainty for the output from the ocean models.

  8. Water Storage Changes over the Tibetan Plateau Revealed by GRACE Mission

    Science.gov (United States)

    Guo, Jinyun; Mu, Dapeng; Liu, Xin; Yan, Haoming; Sun, Zhongchang; Guo, Bin

    2016-04-01

    We use GRACE gravity data released by the Center for Space Research (CSR) and the Groupe de Recherches en Geodesie Spatiale (GRGS) to detect the water storage changes over the Tibetan Plateau (TP). A combined filter strategy is put forward to process CSR RL05 data to remove the effect of striping errors. After the correction for GRACE by GLDAS and ICE-5G, we find that TP has been overall experiencing the water storage increase during 2003-2012. During the same time, the glacier over the Himalayas was sharply retreating. Interms of linear trends, CSR's results derived by the combined filter are close to GRGS RL03 with the Gaussian filter of 300-km window. The water storage increasing rates determined from CSR's RL05 products in the interior TP, Karakoram Mountain, Qaidam Basin, Hengduan Mountain, and middle Himalayas are 9.7, 6.2, 9.1,-18.6, and-20.2 mm/yr, respectively. These rates from GRGS's RL03 products are 8.6, 5.8, 10.5,-19.3 and-21.4 mm/yr, respectively.

  9. Eternal extended inflation and graceful exit from old inflation without Jordan-Brans-Dicke

    Science.gov (United States)

    Linde, Andrei

    1990-10-01

    Recently a possible solution to the graceful exit problem of the old inflation was proposed in the context of the Jordan-Brans-Dicke theory (extended inflation). In this paper we will argue that inflation in this theory occurs in a most natural way if it starts near the Planck density, as in the standard version of chaotic inflation. With most natural initial conditions, the inflationary universe in the JBD theory enters the stage of permanent reproduction of new inflationary domains (eternal extended inflation). In order to realize the extended inflation scenario at least two classical scalar fields driving inflation are necessary, as distinct from the simplest versions of new and chaotic inflation. It is shown that in the theory of two scalar fields one can solve the graceful exit problem even without modifying the Einstein gravity theory, due to the possibility that the decay rate of the false rate vacuum in old inflation depends on the value of the second scalar field and hence on time. Address after 1 September 1990: Physics Department, Stanford University, Varian Building, Stanford, CA 94305, USA.

  10. Graceful Failure, Engineering, and Planning for Extremes: The Engineering for Climate Extremes Partnership (ECEP)

    Science.gov (United States)

    Bruyere, C. L.; Tye, M. R.; Holland, G. J.; Done, J.

    2015-12-01

    Graceful failure acknowledges that all systems will fail at some level and incorporates the potential for failure as a key component of engineering design, community planning, and the associated research and development. This is a fundamental component of the ECEP, an interdisciplinary partnership bringing together scientific, engineering, cultural, business and government expertise to develop robust, well-communicated predictions and advice on the impacts of weather and climate extremes in support of decision-making. A feature of the partnership is the manner in which basic and applied research and development is conducted in direct collaboration with the end user. A major ECEP focus is the Global Risk and Resilience Toolbox (GRRT) that is aimed at developing public-domain, risk-modeling and response data and planning system in support of engineering design, and community planning and adaptation activities. In this presentation I will outline the overall ECEP and GRIP activities, and expand on the 'graceful failure' concept. Specific examples for direct assessment and prediction of hurricane impacts and damage potential will be included.

  11. Long term ice sheet mass change rates and inter-annual variability from GRACE gravimetry.

    Science.gov (United States)

    Harig, C.

    2017-12-01

    The GRACE time series of gravimetry now stretches 15 years since its launch in 2002. Here we use Slepian functions to estimate the long term ice mass trends of Greenland, Antarctica, and several glaciated regions. The spatial representation shows multi-year to decadal regional shifts in accelerations, in agreement with increases in radar derived ice velocity. Interannual variations in ice mass are of particular interest since they can directly link changes in ice sheets to the drivers of change in the polar ocean and atmosphere. The spatial information retained in Slepian functions provides a tool to determine how this link varies in different regions within an ice sheet. We present GRACE observations of the 2013-2014 slowdown in mass loss of the Greenland ice sheet, which was concentrated in specific parts of the ice sheet and in certain months of the year. We also discuss estimating the relative importance of climate factors that control ice mass balance, as a function of location of the glacier/ice cap as well as the spatial variation within an ice sheet by comparing gravimetry with observations of surface air temperature, ocean temperature, etc. as well as model data from climate reanalysis products.

  12. GRACE Detected Rise of Groundwater in the Sahelian Niger River Basin

    Science.gov (United States)

    Werth, S.; White, D.; Bliss, D. W.

    2017-12-01

    West African regions along the Niger River experience climate and land cover changes that affect hydrological processes and therewith the distribution of fresh water resources (WR). This study provides an investigation of long-term changes in terrestrial water storages (TWS) of the Niger River basin and its subregions by analyzing a decade of satellite gravity data from the Gravity Recovery and Climate Experiment (GRACE) mission. The location of large trends in TWS maps of differently processed GRACE solutions points to rising groundwater stocks. Soil moisture data from a global land surface model allow separating the effect of significantly increasing amount of WR from that of TWS variations. Surface water variations from a global water storage model validated with observations from altimetry data were applied to estimate the groundwater component in WR. For the whole Niger, a rise in groundwater stocks is estimated to be 93 ± 61 km3 between January 2003 and December 2013. A careful analysis of uncertainties in all data sets supports the significance of the groundwater rise. Our results confirm previous observations of rising water tables, indicating that effects of land cover changes on groundwater storage are relevant on basin scales. Areas with rising water storage are stocking a comfortable backup to mitigate possible future droughts and to deliver water to remote areas. This has implications for Niger water management strategies. Increasing groundwater recharges may be accompanied by reduction in water quality. This study helps to inform authority's decision to mitigate its negative impacts on local communities.

  13. Recovery of the Three-Gorges Reservoir Impoundment Signal from ICESat altimetry and GRACE

    Science.gov (United States)

    Carabajal, C. C.; Boy, J.; Luthcke, S. B.; Harding, D. J.; Rowlands, D. D.; Lemoine, F. G.

    2006-12-01

    The Three Gorges Dam along the Yangtze River in China is one of the largest dams in the world. The water impoundment of the Three-Gorges Reservoir started in June 2003, and the volume of water will continuously increase up to about 40 km3 in 2009, over a length of about 600 km. Although water-level changes along the Yangtze River and the Three Gorges Reservoir are measured by in situ water gauges, access to these data can be quite difficult. Estimates of inland water height and extent can also be recovered from altimetry measurements performed from satellite platforms, such as those acquired by the Geoscience laser Altimetry System (GLAS) on board the Ice, Cloud and Land Elevation Satellite (ICESat). ICESat has produced a comprehensive, highly precise, set of along-track elevation measurements, every three months since its launch in 2003, which intersect the Yangtze River along its East-West extent. In addition, the water impoundment of major artificial reservoirs induces variations of global geodetic quantities, such as the gravity field and Earth rotation (Chao, 1995, Boy & Chao, 2002). Water level changes within the reservoir are compared to GRACE (Gravity Recovery And Climate Experiment) recovered water mass changes. In addition, we compare the GRACE observations of mass change in the Yangtze region to hydrological changes computed from different global soil-moisture and snow models, such as GLDAS (Global Land Data Assimilation System).

  14. Design and baseline data from the Gratitude Research in Acute Coronary Events (GRACE) study.

    Science.gov (United States)

    Huffman, Jeff C; Beale, Eleanor E; Beach, Scott R; Celano, Christopher M; Belcher, Arianna M; Moore, Shannon V; Suarez, Laura; Gandhi, Parul U; Motiwala, Shweta R; Gaggin, Hanna; Januzzi, James L

    2015-09-01

    Positive psychological constructs, especially optimism, have been linked with superior cardiovascular health. However, there has been minimal study of positive constructs in patients with acute coronary syndrome (ACS), despite the prevalence and importance of this condition. Furthermore, few studies have examined multiple positive psychological constructs and multiple cardiac-related outcomes within the same cohort to determine specifically which positive construct may affect a particular cardiac outcome. The Gratitude Research in Acute Coronary Events (GRACE) study examines the association between optimism/gratitude 2weeks post-ACS and subsequent clinical outcomes. The primary outcome measure is physical activity at 6months, measured via accelerometer, and key secondary outcome measures include levels of prognostic biomarkers and rates of nonelective cardiac rehospitalization at 6months. These relationships will be analyzed using multivariable linear regression, controlling for sociodemographic, medical, and negative psychological factors; associations between baseline positive constructs and subsequent rehospitalizations will be assessed via Cox regression. Overall, 164 participants enrolled and completed the baseline 2-week assessment; the cohort had a mean age of 61.5+/?10.5years and was 84% men; this was the first ACS for 58% of participants. The GRACE study will determine whether optimism and gratitude are prospectively and independently associated with physical activity and other critical outcomes in the 6months following an ACS. If these constructs are associated with superior outcomes, this may highlight the importance of these constructs as independent prognostic factors post-ACS. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Improving Soil Moisture Estimation through the Joint Assimilation of SMOS and GRACE Satellite Observations

    Science.gov (United States)

    Girotto, Manuela

    2018-01-01

    Observations from recent soil moisture dedicated missions (e.g. SMOS or SMAP) have been used in innovative data assimilation studies to provide global high spatial (i.e., approximately10-40 km) and temporal resolution (i.e., daily) soil moisture profile estimates from microwave brightness temperature observations. These missions are only sensitive to near-surface soil moisture 0-5 cm). In contrast, the Gravity Recovery and Climate Experiment (GRACE) mission provides accurate measurements of the entire vertically integrated terrestrial water storage (TWS) column but, it is characterized by low spatial (i.e., 150,000 km2) and temporal (i.e., monthly) resolutions. Data assimilation studies have shown that GRACE-TWS primarily affects (in absolute terms) deeper moisture storages (i.e., groundwater). In this presentation I will review benefits and drawbacks associated to the assimilation of both types of observations. In particular, I will illustrate the benefits and drawbacks of their joint assimilation for the purpose of improving the entire profile of soil moisture (i.e., surface and deeper water storages).

  16. Eternal extended inflation and graceful exit from old inflation without Jordan-Brans-Dicke

    International Nuclear Information System (INIS)

    Linde, A.

    1990-01-01

    Recently a possible solution to the graceful exit problem of the old inflation was proposed in the context of the Jordan-Brans-Dicke theory (extended inflation). In this paper we will argue that inflation in this theory occurs in a most natural way if it starts near the Planck density, as in the standard version of chaotic inflation. With most natural initial conditions, the inflationary universe in the JBD theory enters the stage of permanent reproduction of new inflationary domains (eternal extended inflation). In order to realize the extended inflation scenario at least two classical scalar fields driving inflation are necessary, as distinct from the simplest versions of new and chaotic inflation. It is shown that in the theory of two scalar fields one can solve the graceful exit problem even without modifying the Einstein gravity theory, due to the possibility that the decay rate of the false vacuum in old inflation depends on the value of the second scalar field and hence on time. (orig.)

  17. 'Grounded' Politics

    DEFF Research Database (Denmark)

    Schmidt, Garbi

    2012-01-01

    play within one particular neighbourhood: Nørrebro in the Danish capital, Copenhagen. The article introduces the concept of grounded politics to analyse how groups of Muslim immigrants in Nørrebro use the space, relationships and history of the neighbourhood for identity political statements....... The article further describes how national political debates over the Muslim presence in Denmark affect identity political manifestations within Nørrebro. By using Duncan Bell’s concept of mythscape (Bell, 2003), the article shows how some political actors idealize Nørrebro’s past to contest the present...... ethnic and religious diversity of the neighbourhood and, further, to frame what they see as the deterioration of genuine Danish identity....

  18. Characterizing hydrological activities over Yangtze River basin using the new HUST-Grace2016 model, MODIS, and NCEP/NCAR data

    Science.gov (United States)

    Zhou, H.; Luo, Z.; Tangdamrongsub, N.; He, L.

    2017-12-01

    Accurate TWS estimation is important to evaluate the situation of the water resource over the Yangtze River basin. This study exploits the TWS observation from the new gravity model, HUST-Grace06, which is developed by a new low-frequency noise processing strategy. A novel GRACE post-processing approach is proposed to enhance the quality of the TWS estimate, and the improved TWS is used to characterize the hydrological activities over the Yangtze River basin. The approach includes the effective noise reduction and the leakage error mitigation based on forward modeling. The HUST-Grace06 derived TWS presents good agreement with the CSR mascon solution as well as the PCR-GLOBWB hydrological model. Particularly, our solution provides remarkable performance in identifying the extreme climate events e.g., flood and drought over the Yangtze River basin. In addition, for the first time, the NCEP/NCAR reanalysis data is incorporated with GRACE in the exploration of the climate induced hydrological activities. The comparison between GRACE and the MODIS-derived NDVI data is also conducted to investigate their connection regarding temporal and spatial distribution. The analysis suggests that the terrestrial reflectance data can be used to represent the TWS information. Importantly, such information can be used to fill the missing data in case of the early termination of GRACE or during the prelaunch of the GRACE Follow-On mission.

  19. The potential of GRACE gravimetry to detect the heavy rainfall-induced impoundment of a small reservoir in the upper Yellow River

    Science.gov (United States)

    Yi, Shuang; Song, Chunqiao; Wang, Qiuyu; Wang, Linsong; Heki, Kosuke; Sun, Wenke

    2017-08-01

    Artificial reservoirs are important indicators of anthropogenic impacts on environments, and their cumulative influences on the local water storage will change the gravity signal. However, because of their small signal size, such gravity changes are seldom studied using satellite gravimetry from the Gravity Recovery and Climate Experiment (GRACE). Here we investigate the ability of GRACE to detect water storage changes in the Longyangxia Reservoir (LR), which is situated in the upper main stem of the Yellow River. Three different GRACE solutions from the CSR, GFZ, and JPL with three different processing filters are compared here. We find that heavy precipitation in the summer of 2005 caused the LR water storage to increase by 37.9 m in height, which is equivalent to 13.0 Gt in mass, and that the CSR solutions with a DDK4 filter show the best performance in revealing the synthetic gravity signals. We also obtain 109 pairs of reservoir inundation area measurements from satellite imagery and water level changes from laser altimetry and in situ observations to derive the area-height ratios for the LR. The root mean square of GRACE series in the LR is reduced by 39% after removing synthetic signals caused by mass changes in the LR or by 62% if the GRACE series is further smoothed. We conclude that GRACE data show promising potential in detecting water storage changes in this ˜400 km2 reservoir and that a small signal size is not a restricting factor for detection using GRACE data.

  20. 26 CFR 5.856-1 - Extensions of the grace period for foreclosure property by a real estate investment trust.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Extensions of the grace period for foreclosure property by a real estate investment trust. 5.856-1 Section 5.856-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) TEMPORARY INCOME TAX REGULATIONS UNDER THE REVENUE ACT OF 1978 § 5.856-1...

  1. Quantifying the resolution level where the GRACE satellites can separate Greenland's glacial mass balance from surface mass balance

    Science.gov (United States)

    Bonin, J. A.; Chambers, D. P.

    2015-09-01

    Mass change over Greenland can be caused by either changes in the glacial dynamic mass balance (DMB) or the surface mass balance (SMB). The GRACE satellite gravity mission cannot directly separate the two physical causes because it measures the sum of the entire mass column with limited spatial resolution. We demonstrate one theoretical way to indirectly separate cumulative SMB from DMB with GRACE, using a least squares inversion technique with knowledge of the location of the glaciers. However, we find that the limited 60 × 60 spherical harmonic representation of current GRACE data does not provide sufficient resolution to adequately accomplish the task. We determine that at a maximum degree/order of 90 × 90 or above, a noise-free gravity measurement could theoretically separate the SMB from DMB signals. However, current GRACE satellite errors are too large at present to separate the signals. A noise reduction of a factor of 10 at a resolution of 90 × 90 would provide the accuracy needed for the interannual cumulative SMB and DMB to be accurately separated.

  2. Distributed fault slip model for the 2011 Tohoku-Oki earthquake from GNSS and GRACE/GOCE satellite gravimetry

    NARCIS (Netherlands)

    Fuchs, Martin Johann; Hooper, Andrew; Broerse, D.B.T.; Bouman, Johannes

    2016-01-01

    The Gravity Recovery and Climate Experiment (GRACE) mission (launched 2002) and the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) mission (March 2009 to November 2013) collected spaceborne gravity data for the preseismic and postseismic periods of the 2011 Tohoku-Oki

  3. Modelling the Earth's static and time-varying gravity field using a combination of GRACE and GOCE data

    NARCIS (Netherlands)

    Farahani, H.H.

    2013-01-01

    The main focus of the thesis is modelling the static and time-varying parts of the Earth's gravity field at the global scale based on data acquired by the Gravity Recovery And Climate Experiment (GRACE) and Gravity field and steady-state Ocean Circulation Explorer (GOCE). In addition, a new

  4. Distributed fault slip model for the 2011 Tohoku-Oki earthquake from GNSS and GRACE/GOCE satellite gravimetry

    NARCIS (Netherlands)

    Fuchs, Martin Johann; Hooper, Andrew; Broerse, Taco|info:eu-repo/dai/nl/411299344; Bouman, Johannes

    The Gravity Recovery and Climate Experiment (GRACE) mission (launched 2002) and the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) mission (March 2009 to November 2013) collected spaceborne gravity data for the preseismic and postseismic periods of the 2011 Tohoku-Oki earthquake.

  5. Improved GRACE regional mass balance estimates of the Greenland ice sheet cross-validated with the input-output method

    NARCIS (Netherlands)

    Xu, Zheng; Schrama, Ernst J. O.; van der Wal, Wouter; van den Broeke, Michiel; Enderlin, Ellyn M.

    2016-01-01

    In this study, we use satellite gravimetry data from the Gravity Recovery and Climate Experiment (GRACE) to estimate regional mass change of the Greenland ice sheet (GrIS) and neighboring glaciated regions using a least squares inversion approach. We also consider results from the input–output

  6. Improved GRACE regional mass balance estimates of the Greenland ice sheet cross-validated with the input–output method

    NARCIS (Netherlands)

    Xu, Z.; Schrama, E.J.O.; van der Wal, W.; van den Broeke, MR; Enderlin, EM

    2016-01-01

    In this study, we use satellite gravimetry data from the Gravity Recovery and Climate Experiment (GRACE) to estimate regional mass change of the Greenland ice sheet (GrIS) and neighboring glaciated regions using a least squares inversion approach. We also consider results from the input–output

  7. Terrestrial water storage changes over the Pearl River Basin from GRACE and connections with Pacific climate variability

    Directory of Open Access Journals (Sweden)

    Zhicai Luo

    2016-05-01

    Full Text Available Time-variable gravity data from the Gravity Recovery and Climate Experiment (GRACE satellite mission are used to study terrestrial water storage (TWS changes over the Pearl River Basin (PRB for the period 2003–Nov. 2014. TWS estimates from GRACE generally show good agreement with those from two hydrological models GLDAS and WGHM. But they show different capability of detecting significant TWS changes over the PRB. Among them, WGHM is likely to underestimate the seasonal variability of TWS, while GRACE detects long-term water depletions over the upper PRB as was done by hydrological models, and observes significant water increases around the Longtan Reservoir (LTR due to water impoundment. The heavy drought in 2011 caused by the persistent precipitation deficit has resulted in extreme low surface runoff and water level of the LTR. Moreover, large variability of summer and autumn precipitation may easily trigger floods and droughts in the rainy season in the PRB, especially for summer, as a high correlation of 0.89 was found between precipitation and surface runoff. Generally, the PRB TWS was negatively correlated with El Niño-Southern Oscillation (ENSO events. However, the modulation of the Pacific Decadal Oscillation (PDO may impact this relationship, and the significant TWS anomaly was likely to occur in the peak of PDO phase as they agree well in both of the magnitude and timing of peaks. This indicates that GRACE-based TWS could be a valuable parameter for studying climatic influences in the PRB.

  8. High-Resolution Assimilation of GRACE Terrestrial Water Storage Observations to Represent Local-Scale Water Table Depths

    Science.gov (United States)

    Stampoulis, D.; Reager, J. T., II; David, C. H.; Famiglietti, J. S.; Andreadis, K.

    2017-12-01

    Despite the numerous advances in hydrologic modeling and improvements in Land Surface Models, an accurate representation of the water table depth (WTD) still does not exist. Data assimilation of observations of the joint NASA and DLR mission, Gravity Recovery and Climate Experiment (GRACE) leads to statistically significant improvements in the accuracy of hydrologic models, ultimately resulting in more reliable estimates of water storage. However, the usually shallow groundwater compartment of the models presents a problem with GRACE assimilation techniques, as these satellite observations account for much deeper aquifers. To improve the accuracy of groundwater estimates and allow the representation of the WTD at fine spatial scales we implemented a novel approach that enables a large-scale data integration system to assimilate GRACE data. This was achieved by augmenting the Variable Infiltration Capacity (VIC) hydrologic model, which is the core component of the Regional Hydrologic Extremes Assessment System (RHEAS), a high-resolution modeling framework developed at the Jet Propulsion Laboratory (JPL) for hydrologic modeling and data assimilation. The model has insufficient subsurface characterization and therefore, to reproduce groundwater variability not only in shallow depths but also in deep aquifers, as well as to allow GRACE assimilation, a fourth soil layer of varying depth ( 1000 meters) was added in VIC as the bottom layer. To initialize a water table in the model we used gridded global WTD data at 1 km resolution which were spatially aggregated to match the model's resolution. Simulations were then performed to test the augmented model's ability to capture seasonal and inter-annual trends of groundwater. The 4-layer version of VIC was run with and without assimilating GRACE Total Water Storage anomalies (TWSA) over the Central Valley in California. This is the first-ever assimilation of GRACE TWSA for the determination of realistic water table depths, at

  9. Characterizing Drought and Flood Events over the Yangtze River Basin Using the HUST-Grace2016 Solution and Ancillary Data

    Directory of Open Access Journals (Sweden)

    Hao Zhou

    2017-10-01

    Full Text Available Accurate terrestrial water storage (TWS estimation is important to evaluate the situation of the water resources over the Yangtze River Basin (YRB. This study exploits the TWS observation from the new temporal gravity field model, HUST-Grace2016 (Huazhong University of Science and Technology, which is developed by a new low-frequency noise processing strategy. A novel GRACE (Gravity Recovery and Climate Experiment post-processing approach is proposed to enhance the quality of the TWS estimate, and the improved TWS is used to characterize the drought and flood events over the YRB. The HUST-Grace2016-derived TWS presents good agreement with the CSR (Center for Space Research mascon solution as well as the PCR-GLOBWB (PCRaster Global Water Balance hydrological model. Particularly, our solution provides remarkable performance in identifying the extreme climate events e.g., flood and drought over the YRB and its sub-basins. The comparison between GRACE-derived TWS variations and the MODIS-derived (Moderate Resolution Imaging Spectroradiometer inundated area variations is then conducted. The analysis demonstrates that the terrestrial reflectance data can provide an alternative way of cross-comparing and validating TWS information in Poyang Lake and Dongting Lake, with a correlation coefficient of 0.77 and 0.70, respectively. In contrast, the correlation is only 0.10 for Tai Lake, indicating the limitation of cross-comparison between MODIS and GRACE data. In addition, for the first time, the NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research vertical velocity data is incorporated with GRACE TWS in the exploration of the climate-induced hydrological activities. The good agreement between non-seasonal NCEP/NCAR vertical velocities and non-seasonal GRACE TWSs is found in flood years (2005, 2010, 2012 and 2016 and drought years (2006, 2011 and 2013. The evidence shown in this study may contribute to the

  10. On the use of the GRACE normal equation of inter-satellite tracking data for estimation of soil moisture and groundwater in Australia

    Directory of Open Access Journals (Sweden)

    N. Tangdamrongsub

    2018-03-01

    Full Text Available An accurate estimation of soil moisture and groundwater is essential for monitoring the availability of water supply in domestic and agricultural sectors. In order to improve the water storage estimates, previous studies assimilated terrestrial water storage variation (ΔTWS derived from the Gravity Recovery and Climate Experiment (GRACE into land surface models (LSMs. However, the GRACE-derived ΔTWS was generally computed from the high-level products (e.g. time-variable gravity fields, i.e. level 2, and land grid from the level 3 product. The gridded data products are subjected to several drawbacks such as signal attenuation and/or distortion caused by a posteriori filters and a lack of error covariance information. The post-processing of GRACE data might lead to the undesired alteration of the signal and its statistical property. This study uses the GRACE least-squares normal equation data to exploit the GRACE information rigorously and negate these limitations. Our approach combines GRACE's least-squares normal equation (obtained from ITSG-Grace2016 product with the results from the Community Atmosphere Biosphere Land Exchange (CABLE model to improve soil moisture and groundwater estimates. This study demonstrates, for the first time, an importance of using the GRACE raw data. The GRACE-combined (GC approach is developed for optimal least-squares combination and the approach is applied to estimate the soil moisture and groundwater over 10 Australian river basins. The results are validated against the satellite soil moisture observation and the in situ groundwater data. Comparing to CABLE, we demonstrate the GC approach delivers evident improvement of water storage estimates, consistently from all basins, yielding better agreement on seasonal and inter-annual timescales. Significant improvement is found in groundwater storage while marginal improvement is observed in surface soil moisture estimates.

  11. On the use of the GRACE normal equation of inter-satellite tracking data for estimation of soil moisture and groundwater in Australia

    Science.gov (United States)

    Tangdamrongsub, Natthachet; Han, Shin-Chan; Decker, Mark; Yeo, In-Young; Kim, Hyungjun

    2018-03-01

    An accurate estimation of soil moisture and groundwater is essential for monitoring the availability of water supply in domestic and agricultural sectors. In order to improve the water storage estimates, previous studies assimilated terrestrial water storage variation (ΔTWS) derived from the Gravity Recovery and Climate Experiment (GRACE) into land surface models (LSMs). However, the GRACE-derived ΔTWS was generally computed from the high-level products (e.g. time-variable gravity fields, i.e. level 2, and land grid from the level 3 product). The gridded data products are subjected to several drawbacks such as signal attenuation and/or distortion caused by a posteriori filters and a lack of error covariance information. The post-processing of GRACE data might lead to the undesired alteration of the signal and its statistical property. This study uses the GRACE least-squares normal equation data to exploit the GRACE information rigorously and negate these limitations. Our approach combines GRACE's least-squares normal equation (obtained from ITSG-Grace2016 product) with the results from the Community Atmosphere Biosphere Land Exchange (CABLE) model to improve soil moisture and groundwater estimates. This study demonstrates, for the first time, an importance of using the GRACE raw data. The GRACE-combined (GC) approach is developed for optimal least-squares combination and the approach is applied to estimate the soil moisture and groundwater over 10 Australian river basins. The results are validated against the satellite soil moisture observation and the in situ groundwater data. Comparing to CABLE, we demonstrate the GC approach delivers evident improvement of water storage estimates, consistently from all basins, yielding better agreement on seasonal and inter-annual timescales. Significant improvement is found in groundwater storage while marginal improvement is observed in surface soil moisture estimates.

  12. Gravity changes in mid-west Greenland from GOCE gravity model and gradient data using ground and airborne gravity

    DEFF Research Database (Denmark)

    Tscherning, Carl Christian; Herceg, Matija; Fredenslund Levinsen, Joanna

    GOCE TRF (terrestrial reference frame) vertical anomalous gradients (Tzz) from two periods have been used to determine gravity anomalies changes in mid-west Greenland, where a large mass-loss has been detected using GRACE (Fig. 1). As additional data were used the GOCE DIR-3 model and ground...... gravity at the coast on solid rock, where no mass loss is expected. The methods of Least-Squares Collocation (LSC) and the Reduced Point Mass (RPM) methods have been used, however only LSC included the ground data....

  13. Coseismic and post-seismic signatures of the Sumatra 2004 December and 2005 March earthquakes in GRACE satellite gravity

    Science.gov (United States)

    Panet, I.; Mikhailov, V.; Diament, M.; Pollitz, F.; King, G.; de Viron, O.; Holschneider, M.; Biancale, R.; Lemoine, J.-M.

    2007-01-01

    The GRACE satellite mission has been measuring the Earth's gravity field and its temporal variations since 2002 April. Although these variations are mainly due to mass transfer within the geofluid envelops, they also result from mass displacements associated with phenomena including glacial isostatic adjustment and earthquakes. However, these last contributions are difficult to isolate because of the presence of noise and of geofluid signals, and because of GRACE's coarse spatial resolution (>400 km half-wavelength). In this paper, we show that a wavelet analysis on the sphere helps to retrieve earthquake signatures from GRACE geoid products. Using a wavelet analysis of GRACE geoids products, we show that the geoid variations caused by the 2004 December (Mw = 9.2) and 2005 March (Mw = 8.7) Sumatra earthquakes can be detected. At GRACE resolution, the 2004 December earthquake produced a strong coseismic decrease of the gravity field in the Andaman Sea, followed by relaxation in the area affected by both the Andaman 2004 and the Nias 2005 earthquakes. We find two characteristic timescales for the relaxation, with a fast variation occurring in the vicinity of the Central Andaman ridge. We discuss our coseismic observations in terms of density changes of crustal and upper-mantle rocks, and of the vertical displacements in the Andaman Sea. We interpret the post-seismic signal in terms of the viscoelastic response of the Earth's mantle. The transient component of the relaxation may indicate the presence of hot, viscous material beneath the active Central Andaman Basin. ?? 2007 The Authors Journal compilation ?? 2007 RAS.

  14. Analysis of Groundwater Anomalies Estimated by GRACE and GLDAS Satellite-based Hydrological Model in the Gulf of Mexico

    Science.gov (United States)

    Lotfata, A.; Ambinakudige, S.

    2017-12-01

    Coastal regions face a higher risk of flooding. A rise in sea-level increases flooding chances in low-lying areas. A major concern is the effect of sea-level rise on the depth of the fresh water/salt water interface in the aquifers of the coastal regions. A sea-level change rise impacts the hydrological system of the aquifers. Salt water intrusion into fresh water aquifers increase water table levels. Flooding prone areas in the coast are at a higher risk of salt water intrusion. The Gulf coast is one of the most vulnerable flood areas due to its natural weather patterns. There is not yet a local assessment of the relation between groundwater level and sea-level rising. This study investigates the projected sea-level rise models and the anomalous groundwater level during January 2002 to December 2016. We used the NASA Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) satellite data in the analysis. We accounted the leakage error and the measurement error in GRACE data. GLDAS data was used to calculate the groundwater storage from the total water storage estimated using GRACE data (ΔGW=ΔTWS (soil moisture, surface water, groundwater, and canopy water) - ΔGLDAS (soil moisture, surface water, and canopy water)). The preliminary results indicate that the total water storage is increasing in parts of the Gulf of Mexico. GRACE data show high soil wetness and groundwater levels in Mississippi, Alabama and Texas coasts. Because sea-level rise increases the probability of flooding in the Gulf coast and affects the groundwater, we will analyze probable interactions between sea-level rise and groundwater in the study area. To understand regional sea-level rise patterns, we will investigate GRACE Ocean data along the Gulf coasts. We will quantify ocean total water storage, its salinity, and its relationship with the groundwater level variations in the Gulf coast.

  15. Can GRACE Explain Some of the Main Interannual Polar Motion Signatures?

    Science.gov (United States)

    Adhikari, S.; Ivins, E. R.; Larour, E. Y.

    2016-12-01

    GRACE has provided a series of monthly solutions for water mass transport that now span a 14-year period. A natural question to ask is how much of this mass transport information might be used to reconstruct, theoretically, the non-tidal and non-Chandlerian polar motion at interannual time scales. Reconstruction of the pole position at interannual time scales since 2002 has been performed by Chen et al. (2013, GRL) and Adhikari and Ivins (2016, Science Advances). (The main feature of polar motion that has been evolving since the mid 1990's is the increasing dominance of Greenland ice mass loss.) Here we discuss this reconstruction and the level of error that occurs because of missing information about the spherical harmonic degree 1 and 2 terms and the lack of terms associated with angular momentum transfer in the Louiville equations. Using GRACE observations and complementary solutions of self-attraction/loading problem on an elastically compressible rotating earth, we show that ice mass losses from polar ice sheets, and when combined with changes in continental hydrology, explain nearly the entire amplitude (83±23%) and mean directional shift (within 5.9±7.6°) of recently observed eastward polar motion. We also show that decadal scale pole variations are directly linked to global changes in continental hydrology. The energy sources for such motions are likely to be associated with decadal scale ocean and atmospheric oscillations that also drive 20th century continental wet-dry variability. Interannual variability in pole position, therefore, offers a tool for assessing past stability of our climate, and for the future, now faced with an increased intensity in the water cycle and more vulnerable to ice sheet instability. Figure caption: Observed and reconstructed mean annual pole positions with respect to the 2003-2015 mean position. Blue error band is associated with the reconstructed solution; red signifies additional errors that are related to uncertainty in

  16. GRACE gravity data help constraining seismic models of the 2004 Sumatran earthquake

    Science.gov (United States)

    Cambiotti, G.; Bordoni, A.; Sabadini, R.; Colli, L.

    2011-10-01

    The analysis of Gravity Recovery and Climate Experiment (GRACE) Level 2 data time series from the Center for Space Research (CSR) and GeoForschungsZentrum (GFZ) allows us to extract a new estimate of the co-seismic gravity signal due to the 2004 Sumatran earthquake. Owing to compressible self-gravitating Earth models, including sea level feedback in a new self-consistent way and designed to compute gravitational perturbations due to volume changes separately, we are able to prove that the asymmetry in the co-seismic gravity pattern, in which the north-eastern negative anomaly is twice as large as the south-western positive anomaly, is not due to the previously overestimated dilatation in the crust. The overestimate was due to a large dilatation localized at the fault discontinuity, the gravitational effect of which is compensated by an opposite contribution from topography due to the uplifted crust. After this localized dilatation is removed, we instead predict compression in the footwall and dilatation in the hanging wall. The overall anomaly is then mainly due to the additional gravitational effects of the ocean after water is displaced away from the uplifted crust, as first indicated by de Linage et al. (2009). We also detail the differences between compressible and incompressible material properties. By focusing on the most robust estimates from GRACE data, consisting of the peak-to-peak gravity anomaly and an asymmetry coefficient, that is given by the ratio of the negative gravity anomaly over the positive anomaly, we show that they are quite sensitive to seismic source depths and dip angles. This allows us to exploit space gravity data for the first time to help constraining centroid-momentum-tensor (CMT) source analyses of the 2004 Sumatran earthquake and to conclude that the seismic moment has been released mainly in the lower crust rather than the lithospheric mantle. Thus, GRACE data and CMT source analyses, as well as geodetic slip distributions aided

  17. Use of GRACE determined secular gravity rates for glacial isostatic adjustment studies in North-America

    Science.gov (United States)

    van der Wal, Wouter; Wu, Patrick; Sideris, Michael G.; Shum, C. K.

    2008-10-01

    Monthly geopotential spherical harmonic coefficients from the GRACE satellite mission are used to determine their usefulness and limitations for studying glacial isostatic adjustment (GIA) in North-America. Secular gravity rates are estimated by unweighted least-squares estimation using release 4 coefficients from August 2002 to August 2007 provided by the Center for Space Research (CSR), University of Texas. Smoothing is required to suppress short wavelength noise, in addition to filtering to diminish geographically correlated errors, as shown in previous studies. Optimal cut-off degrees and orders are determined for the destriping filter to maximize the signal to noise ratio. The halfwidth of the Gaussian filter is shown to significantly affect the sensitivity of the GRACE data (with respect to upper mantle viscosity and ice loading history). Therefore, the halfwidth should be selected based on the desired sensitivity. It is shown that increase in water storage in an area south west of Hudson Bay, from the summer of 2003 to the summer of 2006, contributes up to half of the maximum estimated gravity rate. Hydrology models differ in the predictions of the secular change in water storage, therefore even 4-year trend estimates are influenced by the uncertainty in water storage changes. Land ice melting in Greenland and Alaska has a non-negligible contribution, up to one-fourth of the maximum gravity rate. The estimated secular gravity rate shows two distinct peaks that can possibly be due to two domes in the former Pleistocene ice cover: west and south east of Hudson Bay. With a limited number of models, a better fit is obtained with models that use the ICE-3G model compared to the ICE-5G model. However, the uncertainty in interannual variations in hydrology models is too large to constrain the ice loading history with the current data span. For future work in which GRACE will be used to constrain ice loading history and the Earth's radial viscosity profile, it is

  18. Aging Gracefully.

    Science.gov (United States)

    Waldorf, Heidi A

    2017-06-01

    At the Annual Meeting of the American Academy of Dermatology in 2016, I directed the symposium entitled ‘Aging Gracefully’ for the second time. The symposium’s primary learning objective was to give the audience a framework for managing aesthetic patients. In the last decade, there has been a significant increase in the options for and availability of noninvasive and minimally invasive rejuvenation. With that has been an associated surge in interest by physicians and patients. And, as the number of procedures across the globe increases, so too do the number of aesthetically poor outcomes. Most come from practitioners doing paint-by-numbers treatment. As experts in skin biology and treatment, dermatologists should practice the highest-level cosmetic as well as general dermatology. The faculty presented information to aid practitioners how best to approach patients and formulate a cosmetic plan. The faculty discussed important considerations based on patient gender, age, and skin type. Updated information on the science of cosmeceuticals and the benefits of early noninvasive intervention was presented as were next generation devices and alternatives to standard therapies. The faculty have kindly condensed their AAD presentations for this supplement. I thank L’Oréal and the Journal of Drugs in Dermatology for giving us the opportunity to present this information to a wider audience in this e-supplement. Heidi A. Waldorf MD Director of Laser & Cosmetic Dermatology, The Mount Sinai Hospital, New York, NY Icahn School of Medicine of Mount Sinai, New York, NY Waldorf Dermatology Aesthetics, Nanuet, NY

  19. Minimalism's Grace.

    Science.gov (United States)

    Mills, Mark

    2003-01-01

    Notes that central to the short story form are three tools of fiction: voice; point of view; and setting. Discusses examples of short stories by famous authors. Explains that the very short story has become popular with high school and college teachers as a way to pique students' interest in writing fiction and in analyzing complex longer stories…

  20. Crossing borders: displacement and the constitution od subjectivity in "Alias Grace", by Margaret Atwood

    Directory of Open Access Journals (Sweden)

    Thiago M. Moyano

    2018-04-01

    Full Text Available ABSTRACT: In the poststructuralist turn, a less unified and universalizing concept of space as merely a meaningless stage is proposed. Such notion, as Michel Foucault announced in the 1970s, will no longer be perceived by its fixity or a simply referential aspect, acquiring, among different forums of discussion in the Humanities, a dynamic character. In parallel fashion, studies concerning the constitution of subjectivity point towards its oscillating status, showing how the subject is the product of multiple discourses, which makes any demarcating of solid frontiers, a hard task. The present work aims at analyzing the novel Alias Grace (1996 by Margaret Atwood, under the light of spatial criticism, as well as Gender theory, deconstructing essentialisms around women. In this novel, Atwood gives voice to the historical figure Grace Marks, young Irish immigrant in the XIX century, which becomes mentor and accomplice of the murder of her employer, Thomas Kinnear, and his mistress and governess of the house, Nancy Montgomery. The author constructs a self-aware character-narrator who will know how to manipulate, through language, the many contexts in which she finds herself in, reversing the hierarchy of discourse, re-signifying her allegedly inferior position. Works by Philip Wegner and Neil Smith around the notion of space, Lorna McLean and Marilyn Barber about the Irish immigration in Canada, as well as Linda Hutcheon, Chris Weedon, and Jane Flax’s theories will be the theoretical apparatus of this investigation. KEYWORDS: Gender, Space, Post-colonialism, Margaret Atwood. __________________________________ RESUMO: A guinada Pós-estruturalista de meados do século XX propôs uma visão menos unificada e universalizante do conceito de espaço, este visto anteriormente como um mero cenário. Tal noção, conforme prenunciava Foucault nos anos 1970, não mais será compreendida por sua fixidez ou valor referencial, adquirindo, nos mais variados f

  1. Explorations Around "Graceful Failure" in Transportation Infrastructure: Lessons Learned By the Infrastructure and Climate Network (ICNet)

    Science.gov (United States)

    Jacobs, J. M.; Thomas, N.; Mo, W.; Kirshen, P. H.; Douglas, E. M.; Daniel, J.; Bell, E.; Friess, L.; Mallick, R.; Kartez, J.; Hayhoe, K.; Croope, S.

    2014-12-01

    Recent events have demonstrated that the United States' transportation infrastructure is highly vulnerable to extreme weather events which will likely increase in the future. In light of the 60% shortfall of the $900 billion investment needed over the next five years to maintain this aging infrastructure, hardening of all infrastructures is unlikely. Alternative strategies are needed to ensure that critical aspects of the transportation network are maintained during climate extremes. Preliminary concepts around multi-tier service expectations of bridges and roads with reference to network capacity will be presented. Drawing from recent flooding events across the U.S., specific examples for roads/pavement will be used to illustrate impacts, disruptions, and trade-offs between performance during events and subsequent damage. This talk will also address policy and cultural norms within the civil engineering practice that will likely challenge the application of graceful failure pathways during extreme events.

  2. Gracing incidence small angle neutron scattering of incommensurate magnetic structures in MnSi thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, Birgit; Pfleiderer, Christian; Boeni, Peter [Physik Department, Technische Universitaet Muenchen (Germany); Zhang, Shilei; Hesjedal, Thorsten [Clarendon Laboratory, Department of Physics, University of Oxford (United Kingdom); Khaydukov, Yury; Soltwedel, Olaf; Keller, Thomas [Max-Planck-Institut fuer Festkoerperforschung (Germany); Max Planck Society, Outstation at FRM-II (Germany); Muehlbauer, Sebastian [Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany); Chacon, Alfonso [Physik Department, Technische Universitaet Muenchen (Germany); Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany)

    2015-07-01

    The topological stability of skyrmions in bulk samples of MnSi and the observation of spin transfer torque effects at ultra-low current densities have generated great interest in skyrmions in chiral magnets as a new route towards next generation spintronics devices. Yet, the formation of skyrmions in MBE grown thin films of MnSi reported in the literature is highly controversial. We report gracing incidence small angle neutron scattering (GISANS) of the magnetic order in selected thin films of MnSi grown by state of the art MBE techniques. In combination with polarised neutron reflectometry (PNR) and magnetisation measurements of the same samples our data provide direct reciprocal space information of the incommensurate magnetic order, clarifying the nature of magnetic phase diagram.

  3. Equivalent water height extracted from GRACE gravity field model with robust independent component analysis

    Science.gov (United States)

    Guo, Jinyun; Mu, Dapeng; Liu, Xin; Yan, Haoming; Dai, Honglei

    2014-08-01

    The Level-2 monthly GRACE gravity field models issued by Center for Space Research (CSR), GeoForschungs Zentrum (GFZ), and Jet Propulsion Laboratory (JPL) are treated as observations used to extract the equivalent water height (EWH) with the robust independent component analysis (RICA). The smoothing radii of 300, 400, and 500 km are tested, respectively, in the Gaussian smoothing kernel function to reduce the observation Gaussianity. Three independent components are obtained by RICA in the spatial domain; the first component matches the geophysical signal, and the other two match the north-south strip and the other noises. The first mode is used to estimate EWHs of CSR, JPL, and GFZ, and compared with the classical empirical decorrelation method (EDM). The EWH STDs for 12 months in 2010 extracted by RICA and EDM show the obvious fluctuation. The results indicate that the sharp EWH changes in some areas have an important global effect, like in Amazon, Mekong, and Zambezi basins.

  4. Uncertainty estimates of a GRACE inversion modelling technique over Greenland using a simulation

    Science.gov (United States)

    Bonin, Jennifer; Chambers, Don

    2013-07-01

    The low spatial resolution of GRACE causes leakage, where signals in one location spread out into nearby regions. Because of this leakage, using simple techniques such as basin averages may result in an incorrect estimate of the true mass change in a region. A fairly simple least squares inversion technique can be used to more specifically localize mass changes into a pre-determined set of basins of uniform internal mass distribution. However, the accuracy of these higher resolution basin mass amplitudes has not been determined, nor is it known how the distribution of the chosen basins affects the results. We use a simple `truth' model over Greenland as an example case, to estimate the uncertainties of this inversion method and expose those design parameters which may result in an incorrect high-resolution mass distribution. We determine that an appropriate level of smoothing (300-400 km) and process noise (0.30 cm2 of water) gets the best results. The trends of the Greenland internal basins and Iceland can be reasonably estimated with this method, with average systematic errors of 3.5 cm yr-1 per basin. The largest mass losses found from GRACE RL04 occur in the coastal northwest (-19.9 and -33.0 cm yr-1) and southeast (-24.2 and -27.9 cm yr-1), with small mass gains (+1.4 to +7.7 cm yr-1) found across the northern interior. Acceleration of mass change is measurable at the 95 per cent confidence level in four northwestern basins, but not elsewhere in Greenland. Due to an insufficiently detailed distribution of basins across internal Canada, the trend estimates of Baffin and Ellesmere Islands are expected to be incorrect due to systematic errors caused by the inversion technique.

  5. Estimating a Global Hydrological Carrying Capacity Using GRACE Observed Water Stress

    Science.gov (United States)

    An, K.; Reager, J. T.; Famiglietti, J. S.

    2013-12-01

    Global population is expected to reach 9 billion people by the year 2050, causing increased demands for water and potential threats to human security. This study attempts to frame the overpopulation problem through a hydrological resources lens by hypothesizing that observed groundwater trends should be directly attributed to human water consumption. This study analyzes the relationships between available blue water, population, and cropland area on a global scale. Using satellite data from NASA's Gravity Recovery and Climate Experiment (GRACE) along with land surface model data from the Global Land Data Assimilation System (GLDAS), a global groundwater depletion trend is isolated, the validity of which has been verified in many regional studies. By using the inherent distributions of these relationships, we estimate the regional populations that have exceeded their local hydrological carrying capacity. Globally, these populations sum to ~3.5 billion people that are living in presently water-stressed or potentially water-scarce regions, and we estimate total cropland is exceeding a sustainable threshold by about 80 million km^2. Key study areas such as the North China Plain, northwest India, and Mexico City were qualitatively chosen for further analysis of regional water resources and policies, based on our distributions of water stress. These case studies are used to verify the groundwater level changes seen in the GRACE trend . Tfor the many populous, arid regions of the world that have already begun to experience the strains of high water demand.he many populous, arid regions of the world have already begun to experience the strains of high water demand. It will take a global cooperative effort of improving domestic and agricultural use efficiency, and summoning a political will to prioritize environmental issues to adapt to a thirstier planet. Global Groundwater Depletion Trend (Mar 2003-Dec 2011)

  6. Approach of regional gravity field modeling from GRACE data for improvement of geoid modeling for Japan

    Science.gov (United States)

    Kuroishi, Y.; Lemoine, F. G.; Rowlands, D. D.

    2006-12-01

    The latest gravimetric geoid model for Japan, JGEOID2004, suffers from errors at long wavelengths (around 1000 km) in a range of +/- 30 cm. The model was developed by combining surface gravity data with a global marine altimetric gravity model, using EGM96 as a foundation, and the errors at long wavelength are presumably attributed to EGM96 errors. The Japanese islands and their vicinity are located in a region of plate convergence boundaries, producing substantial gravity and geoid undulations in a wide range of wavelengths. Because of the geometry of the islands and trenches, precise information on gravity in the surrounding oceans should be incorporated in detail, even if the geoid model is required to be accurate only over land. The Kuroshio Current, which runs south of Japan, causes high sea surface variability, making altimetric gravity field determination complicated. To reduce the long-wavelength errors in the geoid model, we are investigating GRACE data for regional gravity field modeling at long wavelengths in the vicinity of Japan. Our approach is based on exclusive use of inter- satellite range-rate data with calibrated accelerometer data and attitude data, for regional or global gravity field recovery. In the first step, we calibrate accelerometer data in terms of scales and biases by fitting dynamically calculated orbits to GPS-determined precise orbits. The calibration parameters of accelerometer data thus obtained are used in the second step to recover a global/regional gravity anomaly field. This approach is applied to GRACE data obtained for the year 2005 and resulting global/regional gravity models are presented and discussed.

  7. Global seasonal strain and stress models derived from GRACE loading, and their impact on seismicity

    Science.gov (United States)

    Chanard, K.; Fleitout, L.; Calais, E.; Craig, T. J.; Rebischung, P.; Avouac, J. P.

    2017-12-01

    Loading by continental water, atmosphere and oceans deforms the Earth at various spatio-temporal scales, inducing crustal and mantelic stress perturbations that may play a role in earthquake triggering.Deformation of the Earth by this surface loading is observed in GNSS position time series. While various models predict well vertical observations, explaining horizontal displacements remains challenging. We model the elastic deformation induced by loading derived from GRACE for coefficients 2 and higher. We estimate the degree-1 deformation field by comparison between predictions of our model and IGS-repro2 solutions at a globally distributed network of 700 GNSS sites, separating the horizontal and vertical components to avoid biases between components. The misfit between model and data is reduced compared to previous studies, particularly on the horizontal component. The associated geocenter motion time series are consistent with results derived from other datasets. We also discuss the impact on our results of systematic errors in GNSS geodetic products, in particular of the draconitic error.We then compute stress tensors time series induced by GRACE loads and discuss the potential link between large scale seasonal mass redistributions and seismicity. Within the crust, we estimate hydrologically induced stresses in the intraplate New Madrid Seismic Zone, where secular stressing rates are unmeasurably low. We show that a significant variation in the rate of micro-earthquakes at annual and multi-annual timescales coincides with stresses induced by hydrological loading in the upper Mississippi embayment, with no significant phase-lag, directly modulating regional seismicity. We also investigate pressure variations in the mantle transition zone and discuss potential correlations between the statistically significant observed seasonality of deep-focus earthquakes, most likely due to mineralogical transformations, and surface hydrological loading.

  8. Temporal and spatial variabilities of Antarctic ice mass changes inferred by GRACE in a Bayesian framework

    Science.gov (United States)

    Wang, L.; Davis, J. L.; Tamisiea, M. E.

    2017-12-01

    The Antarctic ice sheet (AIS) holds about 60% of all fresh water on the Earth, an amount equivalent to about 58 m of sea-level rise. Observation of AIS mass change is thus essential in determining and predicting its contribution to sea level. While the ice mass loss estimates for West Antarctica (WA) and the Antarctic Peninsula (AP) are in good agreement, what the mass balance over East Antarctica (EA) is, and whether or not it compensates for the mass loss is under debate. Besides the different error sources and sensitivities of different measurement types, complex spatial and temporal variabilities would be another factor complicating the accurate estimation of the AIS mass balance. Therefore, a model that allows for variabilities in both melting rate and seasonal signals would seem appropriate in the estimation of present-day AIS melting. We present a stochastic filter technique, which enables the Bayesian separation of the systematic stripe noise and mass signal in decade-length GRACE monthly gravity series, and allows the estimation of time-variable seasonal and inter-annual components in the signals. One of the primary advantages of this Bayesian method is that it yields statistically rigorous uncertainty estimates reflecting the inherent spatial resolution of the data. By applying the stochastic filter to the decade-long GRACE observations, we present the temporal variabilities of the AIS mass balance at basin scale, particularly over East Antarctica, and decipher the EA mass variations in the past decade, and their role in affecting overall AIS mass balance and sea level.

  9. Ocean Bottom Pressure Seasonal Cycles and Decadal Trends from GRACE Release-05: Ocean Circulation Implications

    Science.gov (United States)

    Johnson, G. C.; Chambers, D. P.

    2013-12-01

    Ocean mass variations are important for diagnosing sea level budgets, the hydrological cycle and global energy budget, as well as ocean circulation variability. Here seasonal cycles and decadal trends of ocean mass from January 2003 to December 2012, both global and regional, are analyzed using GRACE Release 05 data. The trend of global flux of mass into the ocean approaches 2 cm decade-1 in equivalent sea level rise. Regional trends are of similar magnitude, with the North Pacific, South Atlantic, and South Indian oceans generally gaining mass and other regions losing mass. These trends suggest a spin-down of the North Pacific western boundary current extension and the Antarctic Circumpolar Current in the South Atlantic and South Indian oceans. The global average seasonal cycle of ocean mass is about 1 cm in amplitude, with a maximum in early October and volume fluxes in and out of the ocean reaching 0.5 Sv (1 Sv = 1 × 106 m3 s-1) when integrated over the area analyzed here. Regional patterns of seasonal ocean mass change have typical amplitudes of 1-4 cm, and include maxima in the subtropics and minima in the subpolar regions in hemispheric winters. The subtropical mass gains and subpolar mass losses in the winter spin up both subtropical and subpolar gyres, hence the western boundary current extensions. Seasonal variations in these currents are order 10 Sv, but since the associated depth-averaged current variations are only order 0.1 cm s-1, they would be difficult to detect using in situ oceanographic instruments. a) Amplitude (colors, in cm) and b) phase (colors, in months of the year) of an annual harmonic fit to monthly GRACE Release 05 CSR 500 km smoothed maps (concurrently with a trend and the semiannual harmonic). The 97.5% confidence interval for difference from zero is also indicated (solid black line). Data within 300 km of coastlines are not considered.

  10. Effect of Numerical Error on Gravity Field Estimation for GRACE and Future Gravity Missions

    Science.gov (United States)

    McCullough, Christopher; Bettadpur, Srinivas

    2015-04-01

    In recent decades, gravity field determination from low Earth orbiting satellites, such as the Gravity Recovery and Climate Experiment (GRACE), has become increasingly more effective due to the incorporation of high accuracy measurement devices. Since instrumentation quality will only increase in the near future and the gravity field determination process is computationally and numerically intensive, numerical error from the use of double precision arithmetic will eventually become a prominent error source. While using double-extended or quadruple precision arithmetic will reduce these errors, the numerical limitations of current orbit determination algorithms and processes must be accurately identified and quantified in order to adequately inform the science data processing techniques of future gravity missions. The most obvious numerical limitation in the orbit determination process is evident in the comparison of measured observables with computed values, derived from mathematical models relating the satellites' numerically integrated state to the observable. Significant error in the computed trajectory will corrupt this comparison and induce error in the least squares solution of the gravitational field. In addition, errors in the numerically computed trajectory propagate into the evaluation of the mathematical measurement model's partial derivatives. These errors amalgamate in turn with numerical error from the computation of the state transition matrix, computed using the variational equations of motion, in the least squares mapping matrix. Finally, the solution of the linearized least squares system, computed using a QR factorization, is also susceptible to numerical error. Certain interesting combinations of each of these numerical errors are examined in the framework of GRACE gravity field determination to analyze and quantify their effects on gravity field recovery.

  11. Water Availability in the Tigris-Euphrates River Basin and the Middle East from GRACE

    Science.gov (United States)

    Voss, K.; Famiglietti, J. S.; Lo, M.; de Linage, C.; Swenson, S. C.; Rodell, M.

    2010-12-01

    As water security becomes more tenuous, conflicts and disputes over the appropriate management and allocation of transboundary water resources are sure to arise. In particular, the Middle East faces extreme scarcity as a result of both natural climate variations and the impacts of water management decisions and policies. A recent drought, which began in 2007, caused regional hardships as precious water resources dwindled and collaboration between nations failed to accommodate shared needs. In this work, the area surrounding the Tigris and Euphrates River Basin was selected as a case study to evaluate trends in fresh water availability. Because few complete datasets exist for precipitation, streamflow, evapotranspiration, groundwater or surface water in the area, remote sensing techniques, including GRACE and altimetry, as well as land-surface models were utilized to develop an understanding of the regional hydrology. These observations and model results were used to estimate trends in total water storage and its individual components - soil moisture, snow water equivalent, surface water and groundwater. GRACE data show a clear decrease in total water storage in the Middle East from January 2003 to December 2009, and indicate that the selected region experienced a total volume loss of 143 km3 of water. Supporting datasets suggest that approximately two-thirds of this was a loss of groundwater. These results highlight the impacts of drought conditions on groundwater consumption and of agricultural expansion on available water resources in the region. Furthermore, they raise important political issues regarding water use in transboundary river basins and aquifers, while amplifying the need for increased monitoring and datasets for the core components of the water budget.

  12. Combination of GRACE monthly gravity field solutions from different processing strategies

    Science.gov (United States)

    Jean, Yoomin; Meyer, Ulrich; Jäggi, Adrian

    2018-02-01

    We combine the publicly available GRACE monthly gravity field time series to produce gravity fields with reduced systematic errors. We first compare the monthly gravity fields in the spatial domain in terms of signal and noise. Then, we combine the individual gravity fields with comparable signal content, but diverse noise characteristics. We test five different weighting schemes: equal weights, non-iterative coefficient-wise, order-wise, or field-wise weights, and iterative field-wise weights applying variance component estimation (VCE). The combined solutions are evaluated in terms of signal and noise in the spectral and spatial domains. Compared to the individual contributions, they in general show lower noise. In case the noise characteristics of the individual solutions differ significantly, the weighted means are less noisy, compared to the arithmetic mean: The non-seasonal variability over the oceans is reduced by up to 7.7% and the root mean square (RMS) of the residuals of mass change estimates within Antarctic drainage basins is reduced by 18.1% on average. The field-wise weighting schemes in general show better performance, compared to the order- or coefficient-wise weighting schemes. The combination of the full set of considered time series results in lower noise levels, compared to the combination of a subset consisting of the official GRACE Science Data System gravity fields only: The RMS of coefficient-wise anomalies is smaller by up to 22.4% and the non-seasonal variability over the oceans by 25.4%. This study was performed in the frame of the European Gravity Service for Improved Emergency Management (EGSIEM; http://www.egsiem.eu) project. The gravity fields provided by the EGSIEM scientific combination service (ftp://ftp.aiub.unibe.ch/EGSIEM/) are combined, based on the weights derived by VCE as described in this article.

  13. Antarctic Mass Loss from GRACE from Space- and Time-Resolved Modeling with Slepian Functions

    Science.gov (United States)

    Simons, F. J.; Harig, C.

    2013-12-01

    The melting of polar ice sheets is a major contributor to global sea-level rise. Antarctica is of particular interest since most of the mass loss has occurred in West Antarctica, however updated glacial isostatic adjustment (GIA) models and recent mass gains in East Antarctica have reduced the continent-wide integrated decadal trend of mass loss. Here we present a spatially and temporally resolved estimation of the Antarctic ice mass change using Slepian localization functions. With a Slepian basis specifically for Antarctica, the basis functions maximize their energy on the continent and we can project the geopotential fields into a sparse set of orthogonal coefficients. By fitting polynomial functions to the limited basis coefficients we maximize signal-to-noise levels and need not perform smoothing or destriping filters common to other approaches. In addition we determine an empirical noise covariance matrix from the GRACE data to estimate the uncertainty of mass estimation. When applied to large ice sheets, as in our own recent Greenland work, this technique is able to resolve both the overall continental integrated mass trend, as well as the spatial distribution of the mass changes over time. Using CSR-RL05 GRACE data between Jan. 2003 and Jan 2013, we estimate the regional accelerations in mass change for several sub-regions and examine how the spatial pattern of mass has changed. The Amundsen Sea coast of West Antarctica has experienced a large acceleration in mass loss (-26 Gt/yr^2). While mass loss is concentrated near Pine Island and Thwaites glaciers, it has also increased along the coast further towards the Ross ice shelf.

  14. Prediction of GWL with the help of GRACE TWS for unevenly spaced time series data in India : Analysis of comparative performances of SVR, ANN and LRM

    Science.gov (United States)

    Mukherjee, Amritendu; Ramachandran, Parthasarathy

    2018-03-01

    Prediction of Ground Water Level (GWL) is extremely important for sustainable use and management of ground water resource. The motivations for this work is to understand the relationship between Gravity Recovery and Climate Experiment (GRACE) derived terrestrial water change (ΔTWS) data and GWL, so that ΔTWS could be used as a proxy measurement for GWL. In our study, we have selected five observation wells from different geographic regions in India. The datasets are unevenly spaced time series data which restricts us from applying standard time series methodologies and therefore in order to model and predict GWL with the help of ΔTWS, we have built Linear Regression Model (LRM), Support Vector Regression (SVR) and Artificial Neural Network (ANN). Comparative performances of LRM, SVR and ANN have been evaluated with the help of correlation coefficient (ρ) and Root Mean Square Error (RMSE) between the actual and fitted (for training dataset) or predicted (for test dataset) values of GWL. It has been observed in our study that ΔTWS is highly significant variable to model GWL and the amount of total variations in GWL that could be explained with the help of ΔTWS varies from 36.48% to 74.28% (0.3648 ⩽R2 ⩽ 0.7428) . We have found that for the model GWL ∼ Δ TWS, for both training and test dataset, performances of SVR and ANN are better than that of LRM in terms of ρ and RMSE. It also has been found in our study that with the inclusion of meteorological variables along with ΔTWS as input parameters to model GWL, the performance of SVR improves and it performs better than ANN. These results imply that for modelling irregular time series GWL data, ΔTWS could be very useful.

  15. Development of KSC program for investigating and generating field failure rates. Volume 2: Recommended format for reliability handbook for ground support equipment

    Science.gov (United States)

    Bloomquist, C. E.; Kallmeyer, R. H.

    1972-01-01

    Field failure rates and confidence factors are presented for 88 identifiable components of the ground support equipment at the John F. Kennedy Space Center. For most of these, supplementary information regarding failure mode and cause is tabulated. Complete reliability assessments are included for three systems, eight subsystems, and nine generic piece-part classifications. Procedures for updating or augmenting the reliability results presented in this handbook are also included.

  16. Monitoring climate and man-made induced variations in terrestrial water storage (TWS) across Africa using GRACE data

    Science.gov (United States)

    Ahmed, M. E.; Sultan, M.; Wahr, J. M.; Yan, E.; Bonin, J. A.; Chouinard, K.

    2012-12-01

    It is common practice for researchers engaged in research related to climate change to examine the temporal variations in relevant climatic parameters (e.g., temperature, precipitation) and to extract and examine drought indices reproduced from one or more such parameters. Drought indices (meteorological, agricultural and hydrological) define departures from normal conditions and are used as proxies for monitoring water availability. Many of these indices exclude significant controlling factor(s), do not work well in specific settings and regions, and often require long (≥50 yr) calibration time periods and substantial meteorological data, limiting their application in areas lacking adequate observational networks. Additional uncertainties are introduced by the models used in computing model-dependent indices. Aside from these uncertainties, none of these indices measure the variability in terrestrial water storage (TWS), a term that refers to the total vertically integrated water content in an area regardless of the reservoir in which it resides. Inter-annual trends in TWS were extracted from monthly Gravity Recovery and Climate Experiment (GRACE) data acquired (04/2002 to 08/2011) over Africa and correlated (in a GIS environment) with relevant temporal remote sensing, geologic, hydrologic, climatic, and topographic datasets. Findings include the following: (1) large sectors of Africa are undergoing statistically significant variations (+36 mm/yr to -16 mm/yr) due to natural and man-made causes; (2) warming of the tropical Atlantic ocean apparently intensified Atlantic monsoons and increased precipitation and TWS over western and central Africa's coastal plains, proximal mountainous source areas, and inland areas as far as central Chad; (3) warming in the central Indian Ocean decreased precipitation and TWS over eastern and southern Africa; (4) the high frequency of negative phases of the North Atlantic Oscillation (NAO) increased precipitation and TWS over

  17. The potential of GRACE gravimetry to detect the heavy rainfall-induced impoundment of a small reservoir in the upper Yellow River

    OpenAIRE

    Yi, Shuang; Song, Chunqiao; Wang, Qiuyu; Wang, Linsong; Heki, Kosuke; Sun, Wenke

    2017-01-01

    Artificial reservoirs are important indicators of anthropogenic impacts on environments, and their cumulative influences on the local water storage will change the gravity signal. However, because of their small signal size, such gravity changes are seldom studied using satellite gravimetry from the Gravity Recovery and Climate Experiment (GRACE). Here we investigate the ability of GRACE to detect water storage changes in the Longyangxia Reservoir (LR), which is situated in the uppe...

  18. Interannual variability in water storage over 2003-2008 in the Amazon Basin from GRACE space gravimetry, in situ river level and precipitation data

    OpenAIRE

    Xavier , L.; Becker , M.; Cazenave , A.; Longuevergne , L.; Llovel , W.; Rotunno Filho , Otto Correa

    2012-01-01

    International audience; We investigate the interannual variability over 2003-2008 of different hydrological parameters in the Amazon river basin: (1) vertically-integrated water storage from the GRACE space gravimetry mission, (2) surface water level of the Amazon River and its tributaries from in situ gauge stations, and (3) precipitation. We analyze the spatio-temporal evolution of total water storage from GRACE and in situ river level along the Amazon River and its main tributaries and not...

  19. Estimating geocenter motion and barystatic sea-level variability from GRACE observations with explicit consideration of self-attraction and loading effects

    Science.gov (United States)

    Bergmann-Wolf, Inga; Dobslaw, Henryk

    2016-04-01

    Estimating global barystatic sea-level variations from monthly mean gravity fields delivered by the Gravity Recovery and Climate Experiment (GRACE) satellite mission requires additional information about geocenter motion. These variations are not available directly due to the mission implementation in the CM-frame and are represented by the degree-1 terms of the spherical harmonics expansion. Global degree-1 estimates can be determined with the method of Swenson et al. (2008) from ocean mass variability, the geometry of the global land-sea distribution, and GRACE data of higher degrees and orders. Consequently, a recursive relation between the derivation of ocean mass variations from GRACE data and the introduction of geocenter motion into GRACE data exists. In this contribution, we will present a recent improvement to the processing strategy described in Bergmann-Wolf et al. (2014) by introducing a non-homogeneous distribution of global ocean mass variations in the geocenter motion determination strategy, which is due to the effects of loading and self-attraction induced by mass redistributions at the surface. A comparison of different GRACE-based oceanographic products (barystatic signal for both the global oceans and individual basins; barotropic transport variations of major ocean currents) with degree-1 terms estimated with a homogeneous and non-homogeneous ocean mass representation will be discussed, and differences in noise levels in most recent GRACE solutions from GFZ (RL05a), CSR, and JPL (both RL05) and their consequences for the application of this method will be discussed. Swenson, S., D. Chambers and J. Wahr (2008), Estimating geocenter variations from a combination of GRACE and ocean model output, J. Geophys. Res., 113, B08410 Bergmann-Wolf, I., L. Zhang and H. Dobslaw (2014), Global Eustatic Sea-Level Variations for the Approximation of Geocenter Motion from GRACE, J. Geod. Sci., 4, 37-48

  20. Gravity Recovery and Climate Experiment (GRACE) detection of water storage changes in the Three Gorges Reservoir of China and comparison with in situ measurements

    Science.gov (United States)

    Wang, Xianwei; de Linage, Caroline; Famiglietti, James; Zender, Charles S.

    2011-12-01

    Water impoundment in the Three Gorges Reservoir (TGR) of China caused a large mass redistribution from the oceans to a concentrated land area in a short time period. We show that this mass shift is captured by the Gravity Recovery and Climate Experiment (GRACE) unconstrained global solutions at a 400 km spatial resolution after removing correlated errors. The WaterGAP Global Hydrology Model (WGHM) is selected to isolate the TGR contribution from regional water storage changes. For the first time, this study compares the GRACE (minus WGHM) estimated TGR volume changes with in situ measurements from April 2002 to May 2010 at a monthly time scale. During the 8 year study period, GRACE-WGHM estimated TGR volume changes show an increasing trend consistent with the TGR in situ measurements and lead to similar estimates of impounded water volume. GRACE-WGHM estimated total volume increase agrees to within 14% (3.2 km3) of the in situ measurements. This indicates that GRACE can retrieve the true amplitudes of large surface water storage changes in a concentrated area that is much smaller than the spatial resolution of its global harmonic solutions. The GRACE-WGHM estimated TGR monthly volume changes explain 76% (r2 = 0.76) of in situ measurement monthly variability and have an uncertainty of 4.62 km3. Our results also indicate reservoir leakage and groundwater recharge due to TGR filling and contamination from neighboring lakes are nonnegligible in the GRACE total water storage changes. Moreover, GRACE observations could provide a relatively accurate estimate of global water volume withheld by newly constructed large reservoirs and their impacts on global sea level rise since 2002.

  1. Improved predictive value of GRACE risk score combined with platelet reactivity for 1-year cardiovascular risk in patients with acute coronary syndrome who underwent coronary stent implantation.

    Science.gov (United States)

    Li, Shan; Liu, Hongbin; Liu, Jianfeng; Wang, Haijun

    2016-11-01

    Both high platelet reactivity (HPR) and Global Registry of Acute Coronary Events (GRACE) risk score have moderate predictive value for major adverse cardiovascular disease (CVD) events in patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI), whereas the prognostic significance of GRACE risk score combined with platelet function testing remains unclear. A total of 596 patients with non-ST elevation ACS who underwent PCI were enrolled. The P2Y 12 reaction unit (PRU) value was measured by VerifyNow P2Y 12 assay and GRACE score was calculated by GRACE risk 2.0 calculator. Patients were stratified by a pre-specified cutoff value of PRU 230 and GRACE score 140 to assess 1-year risk of cardiovascular death, non-fatal myocardial infarction (MI), and stent thrombosis. Seventy-two (12.1%) patients developed CVD events during 1-year follow-up. Patients with CVD events had a higher PRU value (244.6 ± 50.9 vs. 203.7 ± 52.0, p risk independently. Compared to patients with normal platelet reactivity (NPR) and GRACE score risk (HR: 5.048; 95% CI: 2.268-11.237; p risk score yielded superior risk predictive capacity beyond GRACE score alone, which is shown by improved c-statistic value (0.871, p = 0.002) as well as net reclassification improvement (NRI 0.263, p risk of adverse CVD events. The combination of platelet function testing and GRACE score predicted 1-year CVD risk better.

  2. Relation of the aortic stiffness with the GRACE risk score in patients with the non ST-segment elevation myocardial infarction.

    Science.gov (United States)

    Omer, Gedikli; Gokhan, Aksan; Adem, Uzun; Sabri, Demircan; Korhan, Soylu

    2014-01-01

    Current guidelines recommend clinical risk scoring systems for the patients diagnosed and determinated treatment strategy with in Non-ST-elevation elevation myocardial infarction (NSTEMI). Previous studies demonstrated association between aortic elasticity properties, stiffness and severity CAD. However, the associations between Aortic stiffness, elasticity properties and clinical risk scores have not been investigated. In the present study we have evaluated the relation between the Global Registry of Acute Coronary Events (GRACE) risk score and aortic stiffness in patients with NSTEMI. We prospectively analyzed 87 consecutive patients with NSTEMI. Aortic elastic parameter and stiffness parameter were calculated from the echocardiographically derived thoracic aortic diameters (mm/m(2)), and the measurement of pulse pressure obtained by cuff sphygmomanometry. We have categorized the patients in to two groups as low ((n = 45) (GRACE risk score ≤ 140)) and high ((n = 42) (GRACE risk score > 140)) risk group according to GRACE risk score and compare the both groups. Table 1 shows baseline characteristics of patients. Our study showed that Aortic strain was significantly low (3.5 ± 1.4, 7.9 ± 2.3 respectively, p < 0.001) and aortic stiffness index was significantly high (3.9 ± 0.38; 3 ± 0.35, respectively, p < 0.001) in the high risk group values compared to those with low risk group. The aortic stiffness index was the only independent predictor of GRACE risk score (OR: 119.390; 95% CI: 2.925-4872.8; p = 0.011) in multivariate analysis. We found a significant correlation between aortic stiffness, impaired elasticity and GRACE risk score. Aortic stiffness index was the only independent variable of the high GRACE risk score. The inclusion of aortic stiffness into the GRACE risk score could allow improved risk classification of patients with ACS at admission and this may be important in the diagnosis, follow up and treatment of the patients.

  3. [Prediction value of deceleration capacity of rate and GRACE risk score on major adverse cardiac events in patients with acute myocardial infarction].

    Science.gov (United States)

    Gao, L; Chen, Y D; Shi, Y J; Xue, H; Wang, J L

    2016-07-24

    To investigate the prediction value of deceleration capacity of rate (DC) and GRACE risk score for cardiovascular events in AMI patients. Consecutive AMI patients with sinus rhythm hospitalized in our department during August 2012 to August 2013 were included in this prospective study. 24-hour ECG Holter monitoring was performed within 1 week, and the DC value was analyzed, GRACE risk score was acquired with the application of GRACE risk score calculator. Patients were followed up for more than 1 year and major adverse cardiac events (MACE) were obtained. Analysised the Kaplan Meier survival according to DC and GRACE score risk stratification respectively. A total of 157 patients were enrolled in the study (average age: (58.9±12.7)years old). The average follow-up was (20.54±2.85) months. Mortality during follow-up was significantly higher in patients with DC>2.5 compared to patients with DC≤2.5 (Prisk stratification was 0.898 (95%CI 0.840-0.940, Prisk stratification was 0.786 (95%CI 0.714-0.847, Prisk stratification was 0.708 (95%CI 0.652-0.769, Prisk patients than those with intermediate and low risk patients according to DC risk stratification in intermediate and low risk patients by GRACE risk stratification (Prisk stratification is superior to GRACE risk score on outcome assessment in this AMI patient cohort.

  4. A systematic grounded approach to the development of complex interventions: the Australian WorkHealth Program--arthritis as a case study.

    Science.gov (United States)

    Reavley, Nicola; Livingston, Jenni; Buchbinder, Rachelle; Bennell, Kim; Stecki, Chris; Osborne, Richard Harry

    2010-02-01

    Despite demands for evidence-based research and practice, little attention has been given to systematic approaches to the development of complex interventions to tackle workplace health problems. This paper outlines an approach to the initial stages of a workplace program development which integrates health promotion and disease management. The approach commences with systematic and genuine processes of obtaining information from key stakeholders with broad experience of these interventions. This information is constructed into a program framework in which practice-based and research-informed elements are both valued. We used this approach to develop a workplace education program to reduce the onset and impact of a common chronic disease - osteoarthritis. To gain information systematically at a national level, a structured concept mapping workshop with 47 participants from across Australia was undertaken. Participants were selected to maximise the whole-of-workplace perspective and included health education providers, academics, clinicians and policymakers. Participants generated statements in response to a seeding statement: Thinking as broadly as possible, what changes in education and support should occur in the workplace to help in the prevention and management of arthritis? Participants grouped the resulting statements into conceptually coherent groups and a computer program was used to generate a 'cluster map' along with a list of statements sorted according to cluster membership. In combination with research-based evidence, the concept map informed the development of a program logic model incorporating the program's guiding principles, possible service providers, services, training modes, program elements and the causal processes by which participants might benefit. The program logic model components were further validated through research findings from diverse fields, including health education, coaching, organisational learning, workplace interventions

  5. PV Systems Reliability Final Technical Report: Ground Fault Detection

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flicker, Jack David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We have examined ground faults in PhotoVoltaic (PV) arrays and the efficacy of fuse, current detection (RCD), current sense monitoring/relays (CSM), isolation/insulation (Riso) monitoring, and Ground Fault Detection and Isolation (GFID) using simulations based on a Simulation Program with Integrated Circuit Emphasis SPICE ground fault circuit model, experimental ground faults installed on real arrays, and theoretical equations.

  6. The effect of signal leakage and glacial isostatic rebound on GRACE-derived ice mass changes in Iceland

    DEFF Research Database (Denmark)

    Sørensen, Louise Sandberg; Jarosch, Alexander H.; Adalgeirsdottir, Gudfinna

    2017-01-01

    Monthly gravity field models from the GRACE satellite mission are widely used to determine ice mass changes of large ice sheets as well as smaller glaciers and ice caps. Here, we investigate in detail the ice mass changes of the Icelandic ice caps as derived from GRACE data. The small size...... of the Icelandic ice caps, their location close to other rapidly changing ice covered areas and the low viscosity of the mantle below Iceland make this especially challenging. The mass balance of the ice caps is well constrained by field mass balance measurements, making this area ideal for such investigations. We...... the Little Ice Age (∼ 1890 AD). To minimize the signal that leaks towards Iceland from Greenland, we employ an independent mass change estimate of the Greenland Ice Sheet derived from satellite laser altimetry. We also estimate the effect of post Little Ice Age glacial isostatic adjustment, from knowledge...

  7. Development of an Electromechanical Ground Support System for NASA's Payload Transfer Operations: A Case Study of Multidisciplinary Work in the Space Shuttle Program

    Directory of Open Access Journals (Sweden)

    Felix A. Soto Toro

    2013-04-01

    Full Text Available Space shuttle Atlantis was launched from Kennedy Space Center on July 8, 2011 and landed on July 21, 2011, the final flight of the 30-year Shuttle Program. The development and support of the Space Transportation System (STS had required intensive coordination by scientists and engineers from multiple program disciplines. This paper presents a case study of a typical multidisciplinary effort that was proposed in the late 1990

  8. Modes of Arctic Ocean Change from GRACE, ICESat and the PIOMAS and ECCO2 Models of the Arctic Ocean

    Science.gov (United States)

    Peralta Ferriz, C.; Morison, J. H.; Bonin, J. A.; Chambers, D. P.; Kwok, R.; Zhang, J.

    2012-12-01

    EOF analysis of month-to-month variations in GRACE derived Arctic Ocean bottom pressure (OBP) with trend and seasonal variation removed yield three dominant modes. The first mode is a basin wide variation in mass associated with high atmospheric pressure (SLP) over Scandinavia mainly in winter. The second mode is a shift of mass from the central Arctic Ocean to the Siberian shelves due to low pressure over the basins, associated with the Arctic Oscillation. The third mode is a shift in mass between the Eastern and Western Siberian shelves, related to strength of the Beaufort High mainly in summer, and to eastward alongshore winds on the Barents Sea in winter. The PIOMAS and ECCO2 modeled OBP show fair agreement with the form of these modes and provide context in terms of variations in sea surface height SSH. Comparing GRACE OBP from 2007 to 2011 with GRACE OBP from 2002 to 2006 reveals a rising trend over most of the Arctic Ocean but declines in the Kara Sea region and summer East Siberian Sea. ECCO2 bears a faint resemblance to the observed OBP change but appears to be biased negatively. In contrast, PIOMAS SSH and ECCO2 especially, show changes between the two periods that are muted but similar to ICESat dynamic ocean topography and GRACE-ICESat freshwater trends from 2005 through 2008 [Morison et al., 2012] with a rising DOT and freshening in the Beaufort Sea and a trough with decreased freshwater on the Russian side of the Arctic Ocean. Morison, J., R. Kwok, C. Peralta-Ferriz, M. Alkire, I. Rigor, R. Andersen, and M. Steele (2012), Changing Arctic Ocean freshwater pathways, Nature, 481(7379), 66-70.

  9. Assessing Drought Impacts on Water Storage using GRACE Satellites and Regional Groundwater Modeling in the Central Valley of California

    Science.gov (United States)

    Scanlon, B. R.; Zhang, Z.; Save, H.; Faunt, C. C.; Dettinger, M. D.

    2015-12-01

    Increasing concerns about drought impacts on water resources in California underscores the need to better understand effects of drought on water storage and coping strategies. Here we use a new GRACE mascons solution with high spatial resolution (1 degree) developed at the Univ. of Texas Center for Space Research (CSR) and output from the most recent regional groundwater model developed by the U.S. Geological Survey to evaluate changes in water storage in response to recent droughts. We also extend the analysis of drought impacts on water storage back to the 1980s using modeling and monitoring data. The drought has been intensifying since 2012 with almost 50% of the state and 100% of the Central Valley under exceptional drought in 2015. Total water storage from GRACE data declined sharply during the current drought, similar to the rate of depletion during the previous drought in 2007 - 2009. However, only 45% average recovery between the two droughts results in a much greater cumulative impact of both droughts. The CSR GRACE Mascons data offer unprecedented spatial resolution with no leakage to the oceans and no requirement for signal restoration. Snow and reservoir storage declines contribute to the total water storage depletion estimated by GRACE with the residuals attributed to groundwater storage. Rates of groundwater storage depletion are consistent with the results of regional groundwater modeling in the Central Valley. Traditional approaches to coping with these climate extremes has focused on surface water reservoir storage; however, increasing conjunctive use of surface water and groundwater and storing excess water from wet periods in depleted aquifers is increasing in the Central Valley.

  10. Inferring Large-Scale Terrestrial Water Storage Through GRACE and GPS Data Fusion in Cloud Computing Environments

    Science.gov (United States)

    Rude, C. M.; Li, J. D.; Gowanlock, M.; Herring, T.; Pankratius, V.

    2016-12-01

    Surface subsidence due to depletion of groundwater can lead to permanent compaction of aquifers and damaged infrastructure. However, studies of such effects on a large scale are challenging and compute intensive because they involve fusing a variety of data sets beyond direct measurements from groundwater wells, such as gravity change measurements from the Gravity Recovery and Climate Experiment (GRACE) or surface displacements measured by GPS receivers. Our work therefore leverages Amazon cloud computing to enable these types of analyses spanning the entire continental US. Changes in groundwater storage are inferred from surface displacements measured by GPS receivers stationed throughout the country. Receivers located on bedrock are anti-correlated with changes in water levels from elastic deformation due to loading, while stations on aquifers correlate with groundwater changes due to poroelastic expansion and compaction. Correlating linearly detrended equivalent water thickness measurements from GRACE with linearly detrended and Kalman filtered vertical displacements of GPS stations located throughout the United States helps compensate for the spatial and temporal limitations of GRACE. Our results show that the majority of GPS stations are negatively correlated with GRACE in a statistically relevant way, as most GPS stations are located on bedrock in order to provide stable reference locations and measure geophysical processes such as tectonic deformations. Additionally, stations located on the Central Valley California aquifer show statistically significant positive correlations. Through the identification of positive and negative correlations, deformation phenomena can be classified as loading or poroelastic expansion due to changes in groundwater. This method facilitates further studies of terrestrial water storage on a global scale. This work is supported by NASA AIST-NNX15AG84G (PI: V. Pankratius) and Amazon.

  11. On the estimation of physical height changes using GRACE satellite mission data – A case study of Central Europe

    Directory of Open Access Journals (Sweden)

    Godah Walyeldeen

    2017-12-01

    Full Text Available The dedicated gravity satellite missions, in particular the GRACE (Gravity Recovery and Climate Experiment mission launched in 2002, provide unique data for studying temporal variations of mass distribution in the Earth’s system, and thereby, the geometry and the gravity fi eld changes of the Earth. The main objective of this contribution is to estimate physical height (e.g. the orthometric/normal height changes over Central Europe using GRACE satellite mission data as well as to analyse them and model over the selected study area. Physical height changes were estimated from temporal variations of height anomalies and vertical displacements of the Earth surface being determined over the investigated area. The release 5 (RL05 GRACE-based global geopotential models as well as load Love numbers from the Preliminary Reference Earth Model (PREM were used as input data. Analysis of the estimated physical height changes and their modelling were performed using two methods: the seasonal decomposition method and the PCA/ EOF (Principal Component Analysis/Empirical Orthogonal Function method and the differences obtained were discussed. The main fi ndings reveal that physical height changes over the selected study area reach up to 22.8 mm. The obtained physical height changes can be modelled with an accuracy of 1.4 mm using the seasonal decomposition method.

  12. Deriving Scaling Factors Using a Global Hydrological Model to Restore GRACE Total Water Storage Changes for China's Yangtze River Basin

    Science.gov (United States)

    Long, Di; Yang, Yuting; Yoshihide, Wada; Hong, Yang; Liang, Wei; Chen, Yaning; Yong, Bin; Hou, Aizhong; Wei, Jiangfeng; Chen, Lu

    2015-01-01

    This study used a global hydrological model (GHM), PCR-GLOBWB, which simulates surface water storage changes, natural and human induced groundwater storage changes, and the interactions between surface water and subsurface water, to generate scaling factors by mimicking low-pass filtering of GRACE signals. Signal losses in GRACE data were subsequently restored by the scaling factors from PCR-GLOBWB. Results indicate greater spatial heterogeneity in scaling factor from PCR-GLOBWB and CLM4.0 than that from GLDAS-1 Noah due to comprehensive simulation of surface and subsurface water storage changes for PCR-GLOBWB and CLM4.0. Filtered GRACE total water storage (TWS) changes applied with PCR-GLOBWB scaling factors show closer agreement with water budget estimates of TWS changes than those with scaling factors from other land surface models (LSMs) in China's Yangtze River basin. Results of this study develop a further understanding of the behavior of scaling factors from different LSMs or GHMs over hydrologically complex basins, and could be valuable in providing more accurate TWS changes for hydrological applications (e.g., monitoring drought and groundwater storage depletion) over regions where human-induced interactions between surface water and subsurface water are intensive.

  13. Influence of the Three Gorges Project on the Water Resource Components of Poyang Lake Watershed: Observations from TRMM and GRACE

    Directory of Open Access Journals (Sweden)

    Xiaobin Cai

    2015-01-01

    Full Text Available The Three Gorges Project (TGP has received many criticisms about its potential effects on the changes in the downstream ecosystems. Poyang Lake is the largest body of water downstream of the TGP, and it is not immune to these changes. TRMM and GRACE data were introduced in this study to estimate river-lake water exchange, from which the hydrological responses of Poyang Lake could be identified. A significant decreasing trend of the runoff coefficient has been observed since 2003, resulting in 6.02 km3 more water discharge from the lake into the Yangtze River than under normal conditions. No significant interannual changes occurred in the water level or local precipitation, and GRACE observations revealed that groundwater discharge appeared to be the most likely compensation for the water loss. A novel approach, namely, the groundwater abnormality index (GAI, was developed to depict the water exchange using GRACE and surface water observations. Lower than normal GAIs were found between 2003 and 2005, reaching a minimum of −29.26 in October 2003, corresponding to ten times of the mean GAI during 2006–2012, clearly indicating a significant water exchange in Poyang Lake Basin from groundwater to surface water after the TGP impoundment.

  14. Application of the Regional Water Mass Variations from GRACE Satellite Gravimetry to Large-Scale Water Management in Africa

    Directory of Open Access Journals (Sweden)

    Guillaume Ramillien

    2014-08-01

    Full Text Available Time series of regional 2° × 2° Gravity Recovery and Climate Experiment (GRACE solutions of surface water mass change have been computed over Africa from 2003 to 2012 with a 10-day resolution by using a new regional approach. These regional maps are used to describe and quantify water mass change. The contribution of African hydrology to actual sea level rise is negative and small in magnitude (i.e., −0.1 mm/y of equivalent sea level (ESL mainly explained by the water retained in the Zambezi River basin. Analysis of the regional water mass maps is used to distinguish different zones of important water mass variations, with the exception of the dominant seasonal cycle of the African monsoon in the Sahel and Central Africa. The analysis of the regional solutions reveals the accumulation in the Okavango swamp and South Niger. It confirms the continuous depletion of water in the North Sahara aquifer at the rate of −2.3 km3/y, with a decrease in early 2008. Synergistic use of altimetry-based lake water volume with total water storage (TWS from GRACE permits a continuous monitoring of sub-surface water storage for large lake drainage areas. These different applications demonstrate the potential of the GRACE mission for the management of water resources at the regional scale.

  15. How well are the climate indices related to the GRACE-observed total water storage changes in China?

    Science.gov (United States)

    Devaraju, B.; Vishwakarma, B.; Sneeuw, N. J.

    2017-12-01

    The fresh water availability over land masses is changing rapidly under the influence of climate change and human intervention. In order to manage our water resources and plan for a better future, we need to demarcate the role of climate change. The total water storage change in a region can be obtained from the GRACE satellite mission. On the other hand, many climate change indicators, for example ENSO, are derived from sea surface temperature. In this contribution we investigate the relationship between the total water storage change over China with the climate indices using statistical time-series decomposition techniques, such as Seasonal and Trend decomposition using Loess (STL), Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA). The anomalies in climate variables, such as sea surface temperature, are responsible for anomalous precipitation and thus an anomalous total water storage change over land. Therefore, it is imperative that we use a GRACE product that can capture anomalous water storage changes with unprecedented accuracy. Since filtering decreases the sensitivity of GRACE products substantially, we use the data-driven method of deviation for recovering the signal lost due to filtering. To this end, we are able to obtain the spatial fingerprint of individual climate index on total water storage change observed over China.

  16. Ground water '89

    International Nuclear Information System (INIS)

    1989-01-01

    The proceedings of the 5th biennial symposium of the Ground Water Division of the Geological Society of South Africa are presented. The theme of the symposium was ground water and mining. Papers were presented on the following topics: ground water resources; ground water contamination; chemical analyses of ground water and mining and its influece on ground water. Separate abstracts were prepared for 5 of the papers presented. The remaining papers were considered outside the subject scope of INIS

  17. Developing sustainable management scenarios for Saharan and Arabian aquifer systems using GRACE data

    Science.gov (United States)

    Ahmed, M.; Sultan, M.; Save, H.

    2016-12-01

    Three sources (CSR and JPL Mascons solutions; CSR spherical harmonic fields) of monthly (04/2002 to 03/2016) GRACE-derived TWS estimates were used to develop sustainable utilization scenarios for Saharan and Arabian aquifer systems. These aquifer systems include the Saq Aquifer System in Saudi Arabia (SAS; area: 0.46×106 km2), Nubian Aquifer System in Egypt (NAS; area: 0.66×106 km2), and the Northwestern Saharan Aquifer System in Algeria, Tunisia, and Libya (NWSAS; area: 1.2×106 km2). Piecewise trend analysis of GRACE-derived TWS time series over SAS showed steady-state TWS conditions (0.47 mm/yr; 0.22 km3/yr) during 2002-2006 (Stage I), significant TWS depletion (-13.36 mm/yr; -6.15 km3/yr) during 2006-2012 (Stage II), and signs of replenishment (-3.00 mm/yr; -1.60 km3/yr) during 2012-2016 (Stage III). The pronounced depletion in Stage II is largely related to excessive groundwater extraction mainly for irrigation purposes (2006: irrigated areas/extraction: 502,338 hectare/8.4 km3/yr) compared to those reported in Stage III (2015: irrigated areas/extraction: 326,719 hectare/7.9 km3/yr). Sustainable utilization of SAS waters can be achieved if extraction is reduced to 7.7 km3/yr. The NWSAS showed steady-state conditions (0.02 mm/yr; 0.02 km3/yr) during the 2002-2006 period followed by significant TWS depletions (-4.90 mm/yr; -5.85 km3/yr) due to progressive increase in groundwater extraction (1970: 0.6 km3/yr; 2000: 2.5 km3/yr; 2010: 3 km3/yr). Sustainable utilization of the NWSAS can be achieved if extraction is reduced to 2.5 km3/yr. Trend analysis of GRACE-derived TWS time series over NAS reveals a good correspondence with fluctuations in Lake Nasser Levels (LNL) (2002-2007: LNL/TWS: 177 m/-2.72 mm/yr; 2008-2012: LNL/TWS: 175 m/-7.35 mm/yr; 2013-2016: LNL/TWS: 179 m/11.35 mm/yr) suggesting a causal effect. Given that the average annual (04/2002 to 03/2016) depletion in TWS is -3.24 mm/yr (-2.13 km3/yr), and the average annual extraction is 2.50 km3/yr, we

  18. Investigation of the applicability of a functional programming model to fault-tolerant parallel processing for knowledge-based systems

    Science.gov (United States)

    Harper, Richard

    1989-01-01

    In a fault-tolerant parallel computer, a functional programming model can facilitate distributed checkpointing, error recovery, load balancing, and graceful degradation. Such a model has been implemented on the Draper Fault-Tolerant Parallel Processor (FTPP). When used in conjunction with the FTPP's fault detection and masking capabilities, this implementation results in a graceful degradation of system performance after faults. Three graceful degradation algorithms have been implemented and are presented. A user interface has been implemented which requires minimal cognitive overhead by the application programmer, masking such complexities as the system's redundancy, distributed nature, variable complement of processing resources, load balancing, fault occurrence and recovery. This user interface is described and its use demonstrated. The applicability of the functional programming style to the Activation Framework, a paradigm for intelligent systems, is then briefly described.

  19. GRACE gravity field modeling with an investigation on correlation between nuisance parameters and gravity field coefficients

    Science.gov (United States)

    Zhao, Qile; Guo, Jing; Hu, Zhigang; Shi, Chuang; Liu, Jingnan; Cai, Hua; Liu, Xianglin

    2011-05-01

    The GRACE (Gravity Recovery And Climate Experiment) monthly gravity models have been independently produced and published by several research institutions, such as Center for Space Research (CSR), GeoForschungsZentrum (GFZ), Jet Propulsion Laboratory (JPL), Centre National d’Etudes Spatiales (CNES) and Delft Institute of Earth Observation and Space Systems (DEOS). According to their processing standards, above institutions use the traditional variational approach except that the DEOS exploits the acceleration approach. The background force models employed are rather similar. The produced gravity field models generally agree with one another in the spatial pattern. However, there are some discrepancies in the gravity signal amplitude between solutions produced by different institutions. In particular, 10%-30% signal amplitude differences in some river basins can be observed. In this paper, we implemented a variant of the traditional variational approach and computed two sets of monthly gravity field solutions using the data from January 2005 to December 2006. The input data are K-band range-rates (KBRR) and kinematic orbits of GRACE satellites. The main difference in the production of our two types of models is how to deal with nuisance parameters. This type of parameters is necessary to absorb low-frequency errors in the data, which are mainly the aliasing and instrument errors. One way is to remove the nuisance parameters before estimating the geopotential coefficients, called NPARB approach in the paper. The other way is to estimate the nuisance parameters and geopotential coefficients simultaneously, called NPESS approach. These two types of solutions mainly differ in geopotential coefficients from degree 2 to 5. This can be explained by the fact that the nuisance parameters and the gravity field coefficients are highly correlated, particularly at low degrees. We compare these solutions with the official and published ones by means of spectral analysis. It is

  20. Seismic Safety Margins Research Program, Phase I. Project II: seismic input. Compilation, assessment and expansion of the strong earthquake ground motion data base

    Energy Technology Data Exchange (ETDEWEB)

    Crouse, C B; Hileman, J A; Turner, B E; Martin, G R

    1980-04-01

    A catalog has been prepared which contains information for: (1) world-wide, ground-motion accelerograms, (2) the accelerograph sites where these records were obtained, and (3) the seismological parameters of the causative earthquakes. The catalog is limited to data for those accelerograms which have been digitized and published. In addition, the quality and completeness of these data are assessed. This catalog is unique because it is the only publication which contains comprehensive information on the recording conditions of all known digitized accelerograms. However, information for many accelerograms is missing. Although some literature may have been overlooked, most of the missing data has not been published. Nevertheless, the catalog provides a convenient reference and useful tool for earthquake engineering research and applications.

  1. Grounding Adult Education Research in Rural Areas : Reflections on the Development of a Research Program at the University of Limpopo in South Africa

    NARCIS (Netherlands)

    Zeelen, Jacques; Rampedi, Makgwana; van der Linden, Josje

    Mission statements of universities in developing countries usually include serving the surrounding communities. Often this service does not reach beyond lip service. This article puts into context the experience of developing an adult education research program responding to the needs of the

  2. Denuded Data! Grounded Theory Using the NUDIST Computer Analysis Program: In Researching the Challenge to Teacher Self-Efficacy Posed by Students with Learning Disabilities in Australian Education.

    Science.gov (United States)

    Burroughs-Lange, Sue G.; Lange, John

    This paper evaluates the effects of using the NUDIST (Non-numerical, Unstructured Data Indexing, Searching and Theorising) computer program to organize coded, qualitative data. The use of the software is discussed within the context of the study for which it was used: an Australian study that aimed to develop a theoretical understanding of the…

  3. Programming

    International Nuclear Information System (INIS)

    Jackson, M.A.

    1982-01-01

    The programmer's task is often taken to be the construction of algorithms, expressed in hierarchical structures of procedures: this view underlies the majority of traditional programming languages, such as Fortran. A different view is appropriate to a wide class of problem, perhaps including some problems in High Energy Physics. The programmer's task is regarded as having three main stages: first, an explicit model is constructed of the reality with which the program is concerned; second, this model is elaborated to produce the required program outputs; third, the resulting program is transformed to run efficiently in the execution environment. The first two stages deal in network structures of sequential processes; only the third is concerned with procedure hierarchies. (orig.)

  4. Programming

    OpenAIRE

    Jackson, M A

    1982-01-01

    The programmer's task is often taken to be the construction of algorithms, expressed in hierarchical structures of procedures: this view underlies the majority of traditional programming languages, such as Fortran. A different view is appropriate to a wide class of problem, perhaps including some problems in High Energy Physics. The programmer's task is regarded as having three main stages: first, an explicit model is constructed of the reality with which the program is concerned; second, thi...

  5. Procedures for ground-water investigations

    International Nuclear Information System (INIS)

    1992-12-01

    This manual was developed by the Pacific Northwest Laboratory (PNL) to document the procedures used to carry out and control the technical aspects of ground-water investigations at the PNL. Ground-water monitoring procedures are developed and used in accordance with the PNL Quality Assurance Program

  6. Ground Truth Annotation in T Analyst

    DEFF Research Database (Denmark)

    2015-01-01

    This video shows how to annotate the ground truth tracks in the thermal videos. The ground truth tracks are produced to be able to compare them to tracks obtained from a Computer Vision tracking approach. The program used for annotation is T-Analyst, which is developed by Aliaksei Laureshyn, Ph...

  7. Does simplicity compromise accuracy in ACS risk prediction? A retrospective analysis of the TIMI and GRACE risk scores.

    Directory of Open Access Journals (Sweden)

    Krishna G Aragam

    Full Text Available BACKGROUND: The Thrombolysis in Myocardial Infarction (TIMI risk scores for Unstable Angina/Non-ST-elevation myocardial infarction (UA/NSTEMI and ST-elevation myocardial infarction (STEMI and the Global Registry of Acute Coronary Events (GRACE risk scores for in-hospital and 6-month mortality are established tools for assessing risk in Acute Coronary Syndrome (ACS patients. The objective of our study was to compare the discriminative abilities of the TIMI and GRACE risk scores in a broad-spectrum, unselected ACS population and to assess the relative contributions of model simplicity and model composition to any observed differences between the two scoring systems. METHODOLOGY/PRINCIPAL FINDINGS: ACS patients admitted to the University of Michigan between 1999 and 2005 were divided into UA/NSTEMI (n = 2753 and STEMI (n = 698 subpopulations. The predictive abilities of the TIMI and GRACE scores for in-hospital and 6-month mortality were assessed by calibration and discrimination. There were 137 in-hospital deaths (4%, and among the survivors, 234 (7.4% died by 6 months post-discharge. In the UA/NSTEMI population, the GRACE risk scores demonstrated better discrimination than the TIMI UA/NSTEMI score for in-hospital (C = 0.85, 95% CI: 0.81-0.89, versus 0.54, 95% CI: 0.48-0.60; p<0.01 and 6-month (C = 0.79, 95% CI: 0.76-0.83, versus 0.56, 95% CI: 0.52-0.60; p<0.01 mortality. Among STEMI patients, the GRACE and TIMI STEMI scores demonstrated comparably excellent discrimination for in-hospital (C = 0.84, 95% CI: 0.78-0.90 versus 0.83, 95% CI: 0.78-0.89; p = 0.83 and 6-month (C = 0.72, 95% CI: 0.63-0.81, versus 0.71, 95% CI: 0.64-0.79; p = 0.79 mortality. An analysis of refitted multivariate models demonstrated a marked improvement in the discriminative power of the TIMI UA/NSTEMI model with the incorporation of heart failure and hemodynamic variables. Study limitations included unaccounted for confounders inherent to observational, single institution

  8. Simulated earthquake ground motions

    International Nuclear Information System (INIS)

    Vanmarcke, E.H.; Gasparini, D.A.

    1977-01-01

    The paper reviews current methods for generating synthetic earthquake ground motions. Emphasis is on the special requirements demanded of procedures to generate motions for use in nuclear power plant seismic response analysis. Specifically, very close agreement is usually sought between the response spectra of the simulated motions and prescribed, smooth design response spectra. The features and capabilities of the computer program SIMQKE, which has been widely used in power plant seismic work are described. Problems and pitfalls associated with the use of synthetic ground motions in seismic safety assessment are also pointed out. The limitations and paucity of recorded accelerograms together with the widespread use of time-history dynamic analysis for obtaining structural and secondary systems' response have motivated the development of earthquake simulation capabilities. A common model for synthesizing earthquakes is that of superposing sinusoidal components with random phase angles. The input parameters for such a model are, then, the amplitudes and phase angles of the contributing sinusoids as well as the characteristics of the variation of motion intensity with time, especially the duration of the motion. The amplitudes are determined from estimates of the Fourier spectrum or the spectral density function of the ground motion. These amplitudes may be assumed to be varying in time or constant for the duration of the earthquake. In the nuclear industry, the common procedure is to specify a set of smooth response spectra for use in aseismic design. This development and the need for time histories have generated much practical interest in synthesizing earthquakes whose response spectra 'match', or are compatible with a set of specified smooth response spectra

  9. Ground System Extensibility Considerations

    Science.gov (United States)

    Miller, S. W.; Greene, E.

    2017-12-01

    The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). The Joint Polar Satellite System will replace the afternoon orbit component and ground processing system of the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS). Developed and maintained by Raytheon Intelligence, Information and Services (IIS), the CGS is a multi-mission enterprise system serving NOAA, NASA and their national and international partners, such as NASA's Earth Observation System (EOS), NOAA's current POES, the Japan Aerospace Exploration Agency's (JAXA) Global Change Observation Mission - Water (GCOM-W1), and DoD's Defense Meteorological Satellite Program (DMSP). The CGS provides a wide range of support to a number of national and international missions, including command and control, mission management, data acquisition and routing, and environmental data processing and distribution. The current suite of CGS-supported missions has demonstrated the value of interagency and international partnerships to address global observation needs. With its established infrastructure and existing suite of missions, the CGS is extensible to a wider array of potential new missions. This paper will describe how the inherent scalability and extensibility of the CGS enables the addition of these new missions, with an eye on global enterprise needs in the 2020's and beyond.

  10. Graceful Degradation in 3GPP MBMS Mobile TV Services Using H.264/AVC Temporal Scalability

    Directory of Open Access Journals (Sweden)

    Thomas Wiegand

    2009-01-01

    Full Text Available These days, there is an increasing interest in Mobile TV broadcast services shown by customers as well as service providers. One general problem of Mobile TV broadcast services is to maximize the coverage of users receiving an acceptable service quality, which is mainly influenced by the user's position and mobility within the cell. In this paper, graceful degradation is considered as an approach for improved service availability and coverage. We present a layered transmission approach for 3GPP's Release 6 Multimedia and Broadcast Service (MBMS based on temporal scalability using H.264/AVC Baseline Profile. A differentiation in robustness between temporal quality layers is achieved by unequal error protection approach based on either application layer Forward Error Correction (FEC or unequal transmit power for the layers or even a combination of both. We discuss the corresponding MBMS service as well as network settings and define measures allowing for evaluating the amount of users reached with a certain mobile terminal play-out quality while considering the network cell capacity usage. Using simulated 3GPP Rel. 6 network conditions, we show that if the service and network settings are chosen carefully, a noticeable extension of the coverage of the MBMS service can be achieved.

  11. Using NASA's GRACE and SMAP satellites to measure human impacts on the water cycle

    Science.gov (United States)

    Reager, J. T., II; Castle, S.; Turmon, M.; Famiglietti, J. S.; Fournier, S.

    2017-12-01

    Two satellite missions, the Gravity Recovery and Climate Experiment (GRACE) mission and the Soil Moisture Active Passive (SMAP) mission are enabling the measurement of the dynamic state of the water cycle globally, offering a unique opportunity for the study of human impacts on terrestrial hydrology and an opportunity to quantify the direct augmentation of natural cycles by human activities. While many model-data fusion studies aim to apply observations to improve model performance, we present recent studies on measuring the multi-scale impacts of human activities by differencing or contrasting model simulations and observations. Results that will be presented include studies on: the measurement of human impacts on evapotranspiration in the Colorado River Basin; the estimation of the human portion of groundwater depletion in the Southwestern U.S.; and the influence of irrigation on runoff generation in the Mississippi River basin. Each of these cases has a unique implications for the sustainable use of natural resources by humans, and indicate the relevant extent and magnitude of human influence on natural processes, suggesting their importance for inclusion in hydrology and land-surface models.

  12. Seasonal variations in shallow Alaska seismicity and stress modulation from GRACE derived hydrological loading

    Science.gov (United States)

    Johnson, C. W.; Fu, Y.; Burgmann, R.

    2017-12-01

    Shallow (≤50 km), low magnitude (M≥2.0) seismicity in southern Alaska is examined for seasonal variations during the annual hydrological cycle. The seismicity is declustered with a spatio-temporal epidemic type aftershock sequence (ETAS) model. The removal of aftershock sequences allows detailed investigation of seismicity rate changes, as water and ice loads modulate crustal stresses throughout the year. The GRACE surface loads are obtained from the JPL mass concentration blocks (mascons) global land and ocean solutions. The data product is smoothed with a 9˚ Gaussian filter and interpolated on a 25 km grid. To inform the surface loading model, the global solutions are limited to the region from -160˚ to -120˚ and 50˚ to 70˚. The stress changes are calculated using a 1D spherical layered earth model at depth intervals of 10 km from 10 - 50 km in the study region. To evaluate the induced seasonal stresses, we use >30 years of earthquake focal mechanisms to constrain the background stress field orientation and assess the stress change with respect to the principal stress orientation. The background stress field is assumed to control the preferred orientation of faulting, and stress field perturbations are expected to increase or decrease seismicity. The number of excess earthquakes is calculated with respect to the background seismicity rates. Here, we present preliminary results for the shallow seismicity variations and quantify the seasonal stresses associated with changes in hydrological loading.

  13. Tidal signatures of the thermospheric mass density and zonal wind at midlatitude: CHAMP and GRACE observations

    Directory of Open Access Journals (Sweden)

    C. Xiong

    2015-02-01

    Full Text Available By using the accelerometer measurements from CHAMP and GRACE satellites, the tidal signatures of the thermospheric mass density and zonal wind at midlatitudes have been analyzed in this study. The results show that the mass density and zonal wind at southern midlatitudes are dominated by a longitudinal wave-1 pattern. The most prominent tidal components in mass density and zonal wind are the diurnal tides D0 and DW2 and the semidiurnal tides SW1 and SW3. This is consistent with the tidal signatures in the F region electron density at midlatitudes as reported by Xiong and Lühr (2014. These same tidal components are observed both in the thermospheric and ionospheric quantities, supporting a mechanism that the non-migrating tides in the upper atmosphere are excited in situ by ion–neutral interactions at midlatitudes, consistent with the modeling results of Jones Jr. et al. (2013. We regard the thermospheric dynamics as the main driver for the electron density tidal structures. An example is the in-phase variation of D0 between electron density and mass density in both hemispheres. Further research including coupled atmospheric models is probably needed for explaining the similarities and differences between thermospheric and ionospheric tidal signals at midlatitudes.

  14. Characterization of Terrestrial Water Dynamics in the Congo Basin Using GRACE and Satellite Radar Altimetry

    Science.gov (United States)

    Lee, Lyongki; Beighley, R. Edward; Alsdorf, Douglas; Jung, Hahn Chul; Shum, C. K.; Duan, Jianbin; Guo, Junyi; Yamazaki, Dai; Andreadis, Konstantinos

    2011-01-01

    The Congo Basin is the world's third largest in size (approximately 3.7 million km^2), and second only to the Amazon River in discharge (approximately 40,200 cms annual average). However, the hydrological dynamics of seasonally flooded wetlands and floodplains remains poorly quantified. Here, we separate the Congo wetland into four 3 degree x 3 degree regions, and use remote sensing measurements (i.e., GRACE, satellite radar altimeter, GPCP, JERS-1, SRTM, and MODIS) to estimate the amounts of water filling and draining from the Congo wetland, and to determine the source of the water. We find that the amount of water annually filling and draining the Congo wetlands is 111 km^3, which is about one-third the size of the water volumes found on the mainstem Amazon floodplain. Based on amplitude comparisons among the water volume changes and timing comparisons among their fluxes, we conclude that the local upland runoff is the main source of the Congo wetland water, not the fluvial process of river-floodplain water exchange as in the Amazon. Our hydraulic analysis using altimeter measurements also supports our conclusion by demonstrating that water surface elevations in the wetlands are consistently higher than the adjacent river water levels. Our research also highlights differences in the hydrology and hydrodynamics between the Congo wetland and the mainstem Amazon floodplain.

  15. Migrating pattern of deformation prior to the Tohoku-Oki earthquake revealed by GRACE data

    Science.gov (United States)

    Panet, Isabelle; Bonvalot, Sylvain; Narteau, Clément; Remy, Dominique; Lemoine, Jean-Michel

    2018-05-01

    Understanding how and when far-field continuous motions lead to giant subduction earthquakes remains a challenge. An important limitation comes from an incomplete description of aseismic mass fluxes at depth along plate boundaries. Here we analyse Earth's gravity field variations derived from GRACE satellite data in a wide space-time domain surrounding the Mw 9.0 2011 Tohoku-Oki earthquake. We show that this earthquake is the extreme expression of initially silent deformation migrating from depth to the surface across the entire subduction system. Our analysis indeed reveals large-scale gravity and mass changes throughout three tectonic plates and connected slabs, starting a few months before March 2011. Before the Tohoku-Oki earthquake rupture, the gravity variations can be explained by aseismic extension of the Pacific plate slab at mid-upper mantle depth, concomitant with increasing seismicity in the shallower slab. For more than two years after the rupture, the deformation propagated far into the Pacific and Philippine Sea plate interiors, suggesting that subduction accelerated along 2,000 km of the plate boundaries in March 2011. This gravitational image of the earthquake's long-term dynamics provides unique information on deep and crustal processes over intermediate timescales, which could be used in seismic hazard assessment.

  16. From grass to grace: How SLMTA revolutionised the Bamenda Regional Hospital Laboratory in Cameroon

    Directory of Open Access Journals (Sweden)

    Siyem C. Nkwawir

    2014-11-01

    Objectives: To evaluate the results of SLMTA implementation at BRHL and discuss lessons learned. Method: In 2010, the SLMTA programme was rolled out in Cameroon to improve laboratory quality management systems in five laboratories, including BRHL. Three workshops were conducted (the first centralised, the remaining two on-site at each laboratory and improvement projects were implemented after each workshop with the assistance of mentors. Audits were used in order to evaluate performance and to identify areas for further improvement. Results: BRHL had the lowest score (18% amongst the cohort at the baseline audit and the highest (81% at the official Stepwise Laboratory Quality Improvement Process Towards Accreditation (SLIPTA audit conducted in August 2013 by the African Society for Laboratory Medicine. Improvements were observed in each of the 12 Quality System Essentials; improvement was especially noteworthy in the areas of facilities and safety, and purchasing and inventory. Staff investment and pride in the quality of laboratory services increased. Conclusion: BRHL’s remarkable improvement was achieved with a combination of SLMTA training activities, intensive on-site mentorship and the collective focus of all laboratory staff. The experience at Bamenda Hospital illustrates what can be achieved when a laboratory successfully harnesses the energy of its staff and implements changes to improve the quality of services in a transformation taking them from grass to grace.

  17. EGSIEM combination service: combination of GRACE monthly K-band solutions on normal equation level

    Science.gov (United States)

    Meyer, Ulrich; Jean, Yoomin; Arnold, Daniel; Jäggi, Adrian

    2017-04-01

    The European Gravity Service for Improved Emergency Management (EGSIEM) project offers a scientific combination service, combining for the first time monthly GRACE gravity fields of different analysis centers (ACs) on normal equation (NEQ) level and thus taking all correlations between the gravity field coefficients and pre-eliminated orbit and instrument parameters correctly into account. Optimal weights for the individual NEQs are commonly derived by variance component estimation (VCE), as is the case for the products of the International VLBI Service (IVS) or the DTRF2008 reference frame realisation that are also derived by combination on NEQ-level. But variance factors are based on post-fit residuals and strongly depend on observation sampling and noise modeling, which both are very diverse in case of the individual EGSIEM ACs. These variance factors do not necessarily represent the true error levels of the estimated gravity field parameters that are still governed by analysis noise. We present a combination approach where weights are derived on solution level, thereby taking the analysis noise into account.

  18. Modeling of Thermospheric Neutral Density Variations in Response to Geomagnetic Forcing using GRACE Accelerometer Data

    Science.gov (United States)

    Calabia, A.; Matsuo, T.; Jin, S.

    2017-12-01

    The upper atmospheric expansion refers to an increase in the temperature and density of Earth's thermosphere due to increased geomagnetic and space weather activities, producing anomalous atmospheric drag on LEO spacecraft. Increased drag decelerates satellites, moving their orbit closer to Earth, decreasing the lifespan of satellites, and making satellite orbit determination difficult. In this study, thermospheric neutral density variations due to geomagnetic forcing are investigated from 10 years (2003-2013) of GRACE's accelerometer-based estimates. In order to isolate the variations produced by geomagnetic forcing, 99.8% of the total variability has been modeled and removed through the parameterization of annual, LST, and solar-flux variations included in the primary Empirical Orthogonal Functions. The residual disturbances of neutral density variations have been investigated further in order to unravel their relationship to several geomagnetic indices and space weather activity indicators. Stronger fluctuations have been found in the southern polar cap, following the dipole-tilt angle variations. While the parameterization of the residual disturbances in terms of Dst index results in the best fit to training data, the use of merging electric field as a predictor leads to the best forecasting performance. An important finding is that modeling of neutral density variations in response geomagnetic forcing can be improved by accounting for the latitude-dependent delay. Our data-driven modeling results are further compared to modeling with TIEGCM.

  19. NRC Task Force report on review of the Federal/State program for regulation of commercial low-level radioactive waste burial grounds. Analysis of public comments

    International Nuclear Information System (INIS)

    1977-09-01

    Correspondence after publication of NUREG-0217 in the Federal Register is listed by docket. A summary of the comments is given. Comments on the task force conclusions on federal/state roles, comprehensive regulator program, and need to study alternatives, provide adequate capacity, and avoid proliferation are analyzed. A breakdown of the comments of states, industry, and others on the task force conclusions and recommendations is tabulated

  20. Ground water and energy

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    This national workshop on ground water and energy was conceived by the US Department of Energy's Office of Environmental Assessments. Generally, OEA needed to know what data are available on ground water, what information is still needed, and how DOE can best utilize what has already been learned. The workshop focussed on three areas: (1) ground water supply; (2) conflicts and barriers to ground water use; and (3) alternatives or solutions to the various issues relating to ground water. (ACR)

  1. Improving estimates of water resources in a semi-arid region by assimilating GRACE data into the PCR-GLOBWB hydrological model

    Science.gov (United States)

    Tangdamrongsub, Natthachet; Steele-Dunne, Susan C.; Gunter, Brian C.; Ditmar, Pavel G.; Sutanudjaja, Edwin H.; Sun, Yu; Xia, Ting; Wang, Zhongjing

    2017-04-01

    An accurate estimation of water resources dynamics is crucial for proper management of both agriculture and the local ecology, particularly in semi-arid regions. Imperfections in model physics, uncertainties in model land parameters and meteorological data, as well as the human impact on land changes often limit the accuracy of hydrological models in estimating water storages. To mitigate this problem, this study investigated the assimilation of terrestrial water storage variation (TWSV) estimates derived from the Gravity Recovery And Climate Experiment (GRACE) data using an ensemble Kalman filter (EnKF) approach. The region considered was the Hexi Corridor in northern China. The hydrological model used for the analysis was PCR-GLOBWB, driven by satellite-based forcing data from April 2002 to December 2010. The impact of the GRACE data assimilation (DA) scheme was evaluated in terms of the TWSV, as well as the variation of individual hydrological storage estimates. The capability of GRACE DA to adjust the storage level was apparent not only for the entire TWSV but also for the groundwater component. In this study, spatially correlated errors in GRACE data were taken into account, utilizing the full error variance-covariance matrices provided as a part of the GRACE data product. The benefits of this approach were demonstrated by comparing the EnKF results obtained with and without taking into account error correlations. The results were validated against in situ groundwater data from five well sites. On average, the experiments showed that GRACE DA improved the accuracy of groundwater storage estimates by as much as 25 %. The inclusion of error correlations provided an equal or greater improvement in the estimates. In contrast, a validation against in situ streamflow data from two river gauges showed no significant benefits of GRACE DA. This is likely due to the limited spatial and temporal resolution of GRACE observations. Finally, results of the GRACE DA study

  2. Application of GRACE to the assessment of model-based estimates of monthly Greenland Ice Sheet mass balance (2003-2012)

    Science.gov (United States)

    Schlegel, Nicole-Jeanne; Wiese, David N.; Larour, Eric Y.; Watkins, Michael M.; Box, Jason E.; Fettweis, Xavier; van den Broeke, Michiel R.

    2016-09-01

    Quantifying the Greenland Ice Sheet's future contribution to sea level rise is a challenging task that requires accurate estimates of ice sheet sensitivity to climate change. Forward ice sheet models are promising tools for estimating future ice sheet behavior, yet confidence is low because evaluation of historical simulations is challenging due to the scarcity of continental-wide data for model evaluation. Recent advancements in processing of Gravity Recovery and Climate Experiment (GRACE) data using Bayesian-constrained mass concentration ("mascon") functions have led to improvements in spatial resolution and noise reduction of monthly global gravity fields. Specifically, the Jet Propulsion Laboratory's JPL RL05M GRACE mascon solution (GRACE_JPL) offers an opportunity for the assessment of model-based estimates of ice sheet mass balance (MB) at ˜ 300 km spatial scales. Here, we quantify the differences between Greenland monthly observed MB (GRACE_JPL) and that estimated by state-of-the-art, high-resolution models, with respect to GRACE_JPL and model uncertainties. To simulate the years 2003-2012, we force the Ice Sheet System Model (ISSM) with anomalies from three different surface mass balance (SMB) products derived from regional climate models. Resulting MB is compared against GRACE_JPL within individual mascons. Overall, we find agreement in the northeast and southwest where MB is assumed to be primarily controlled by SMB. In the interior, we find a discrepancy in trend, which we presume to be related to millennial-scale dynamic thickening not considered by our model. In the northwest, seasonal amplitudes agree, but modeled mass trends are muted relative to GRACE_JPL. Here, discrepancies are likely controlled by temporal variability in ice discharge and other related processes not represented by our model simulations, i.e., hydrological processes and ice-ocean interaction. In the southeast, GRACE_JPL exhibits larger seasonal amplitude than predicted by the

  3. Hanford site ground water protection management plan

    International Nuclear Information System (INIS)

    1994-10-01

    Ground water protection at the Hanford Site consists of preventative and remedial measures that are implemented in compliance with a variety of environmental regulations at local, state, and federal levels. These measures seek to ensure that the resource can sustain a broad range of beneficial uses. To effectively coordinate and ensure compliance with applicable regulations, the U.S. Department of Energy has issued DOE Order 5400.1 (DOE 1988a). This order requires all U.S. Department of Energy facilities to prepare separate ground water protection program descriptions and plans. This document describes the Ground Water Protection Management Plan (GPMP) for the Hanford Site located in the state of Washington. DOE Order 5400.1 specifies that the GPMP covers the following general topical areas: (1) documentation of the ground water regime; (2) design and implementation of a ground water monitoring program to support resource management and comply with applicable laws and regulations; (3) a management program for ground water protection and remediation; (4) a summary and identification of areas that may be contaminated with hazardous waste; (5) strategies for controlling hazardous waste sources; (6) a remedial action program; and (7) decontamination, decommissioning, and related remedial action requirements. Many of the above elements are currently covered by existing programs at the Hanford Site; thus, one of the primary purposes of this document is to provide a framework for coordination of existing ground water protection activities. The GPMP provides the ground water protection policy and strategies for ground water protection/management at the Hanford Site, as well as an implementation plan to improve coordination of site ground water activities

  4. Transitions in midwestern ground water law

    International Nuclear Information System (INIS)

    Bowman, J.A.; Clark, G.R.

    1989-01-01

    The evolution of ground-water law in eight states in the Midwest (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, and Wisconsin) is examined, and a review of transitions in ground-water doctrines is presented. Two underlying themes in changing ground-water management are communicated. First, ground-water law is evolving from private property rules of capture based on the absolute ownership doctrines to rules requiring conservation and sharing of ground water as a public resource. Second, in both courts and state legislatures, a proactive role of ground-water management is emerging, again, with an emphasis on sharing. Both of these trends are apparent in the Midwest. In the last decade midwestern states have (1) seen significant shifts in court decisions on ground-water use with greater recognition of the reciprocal or mutually dependent nature of ground-water rights, and (2) seen increased legislative development of comprehensive ground-water management statutes that emphasize the reciprocal liabilities of ground-water use. These trends are examined and ground-water management programs discussed for eight states in the Midwest

  5. PAST: Programa para el proyecto y análisis de sistemas de puesta a tierra. (Primera parte; SistPTEx: Program for the project and analysis of grounding system. (First part.

    Directory of Open Access Journals (Sweden)

    Angel Cecilio Valcárcel Rojas

    2011-05-01

    Full Text Available resistencia de contacto a tierra de diferentes configuraciones de electrodos, desde métodos aproximados, métodos semiexactos, hasta métodos que garantizan muy buenos niveles de exactitud. El desarrollo alcanzado por la computación ha permitido el rescate de algoritmos relativamente antiguos como los basados en la teoría de las imágenes de Maxwell, hasta el desarrollo de métodos basados en la teoría de los elementos finitos. En este trabajo se exponen las características y bondades de un programa para el proyecto y análisis de sistemas de puesta a tierra para cualquier instalación eléctrica, aplicando la teoría de las imágenes de Maxwell.  During the historical development of electrical engineering, have developed many methods for calculating the contact resistance grounding electrodes of different configurations, from approximate methods, semi exact methods up methods which guarantee good levels of exactness. The development achieved by the computer has enabled the rescue of relatively old algorithms, such as those based on the theory of Maxwell’s images, until the development of methods based on the theory of finite elements. In this paper we describe the features and benefits of a program for the design and analysis of grounding systems for any electrical installation, using the theory of Maxwell’s images.

  6. Measurement of ground motion in various sites

    International Nuclear Information System (INIS)

    Bialowons, W.; Amirikas, R.; Bertolini, A.; Kruecker, D.

    2007-04-01

    Ground vibrations may affect low emittance beam transport in linear colliders, Free Electron Lasers (FEL) and synchrotron radiation facilities. This paper is an overview of a study program to measure ground vibrations in various sites which can be used for site characterization in relation to accelerator design. Commercial broadband seismometers have been used to measure ground vibrations and the resultant database is available to the scientific community. The methodology employed is to use the same equipment and data analysis tools for ease of comparison. This database of ground vibrations taken in 19 sites around the world is first of its kind. (orig.)

  7. Hydrology signal from GRACE gravity data in the Nelson River basin, Canada: a comparison of two approaches

    Science.gov (United States)

    Li, Tanghua; Wu, Patrick; Wang, Hansheng; Jia, Lulu; Steffen, Holger

    2018-03-01

    The Gravity Recovery and Climate Experiment (GRACE) satellite mission measures the combined gravity signal of several overlapping processes. A common approach to separate the hydrological signal in previous ice-covered regions is to apply numerical models to simulate the glacial isostatic adjustment (GIA) signals related to the vanished ice load and then remove them from the observed GRACE data. However, the results of this method are strongly affected by the uncertainties of the ice and viscosity models of GIA. To avoid this, Wang et al. (Nat Geosci 6(1):38-42, 2013. https://doi.org/10.1038/NGEO1652; Geodesy Geodyn 6(4):267-273, 2015) followed the theory of Wahr et al. (Geophys Res Lett 22(8):977-980, 1995) and isolated water storage changes from GRACE in North America and Scandinavia with the help of Global Positioning System (GPS) data. Lambert et al. (Postglacial rebound and total water storage variations in the Nelson River drainage basin: a gravity GPS Study, Geological Survey of Canada Open File, 7317, 2013a, Geophys Res Lett 40(23):6118-6122, https://doi.org/10.1002/2013GL057973, 2013b) did a similar study for the Nelson River basin in North America but applying GPS and absolute gravity measurements. However, the results of the two studies in the Nelson River basin differ largely, especially for the magnitude of the hydrology signal which differs about 35%. Through detailed comparison and analysis of the input data, data post-processing techniques, methods and results of these two works, we find that the different GRACE data post-processing techniques may lead to this difference. Also the GRACE input has a larger effect on the hydrology signal amplitude than the GPS input in the Nelson River basin due to the relatively small uplift signal in this region. Meanwhile, the influence of the value of α , which represents the ratio between GIA-induced uplift rate and GIA-induced gravity-rate-of-change (before the correction for surface uplift), is more obvious in

  8. George Washington: A Grounded Leader

    Science.gov (United States)

    2011-04-08

    placed in this book two years after the death of his father likely indicating he was now beginning to take possession of key documents that he...these truths would become part of the strong foundation upon which George would continue to build after the death ofhis father. As George moved into...men and women admired. He was both an I impressive horseman at a time when these talents truly counted, and became an extraordinarily graceful

  9. Mass-induced sea level variations in the Red Sea from GRACE, steric-corrected altimetry, in situ bottom pressure records, and hydrographic observations

    Science.gov (United States)

    Feng, W.; Lemoine, J.-M.; Zhong, M.; Hsu, H. T.

    2014-08-01

    An annual amplitude of ∼18 cm mass-induced sea level variations (SLV) in the Red Sea is detected from the Gravity Recovery and Climate Experiment (GRACE) satellites and steric-corrected altimetry from 2003 to 2011. The annual mass variations in the region dominate the mean SLV, and generally reach maximum in late January/early February. The annual steric component of the mean SLV is relatively small (mass-induced SLV. In situ bottom pressure records at the eastern coast of the Red Sea validate the high mass variability observed by steric-corrected altimetry and GRACE. In addition, the horizontal water mass flux of the Red Sea estimated from GRACE and steric-corrected altimetry is validated by hydrographic observations.

  10. Monthly gravity field solutions based on GRACE observations generated with the Celestial Mechanics Approach

    Science.gov (United States)

    Meyer, Ulrich; Jäggi, Adrian; Beutler, Gerhard

    2012-09-01

    The main objective of the Gravity Recovery And Climate Experiment (GRACE) satellite mission consists of determining the temporal variations of the Earth's gravity field. These variations are captured by time series of gravity field models of limited resolution at, e.g., monthly intervals. We present a new time series of monthly models, which was computed with the so-called Celestial Mechanics Approach (CMA), developed at the Astronomical Institute of the University of Bern (AIUB). The secular and seasonal variations in the monthly models are tested for statistical significance. Calibrated errors are derived from inter-annual variations. The time-variable signal can be extracted at least up to degree 60, but the gravity field coefficients of orders above 45 are heavily contaminated by noise. This is why a series of monthly models is computed up to a maximum degree of 60, but only a maximum order of 45. Spectral analysis of the residual time-variable signal shows a distinctive peak at a period of 160 days, which shows up in particular in the C20 spherical harmonic coefficient. Basic filter- and scaling-techniques are introduced to evaluate the monthly models. For this purpose, the variability over the oceans is investigated, which serves as a measure for the noisiness of the models. The models in selected regions show the expected seasonal and secular variations, which are in good agreement with the monthly models of the Helmholtz Centre Potsdam, German Research Centre for Geosciences (GFZ). The results also reveal a few small outliers, illustrating the necessity for improved data screening. Our monthly models are available at the web page of the International Centre for Global Earth Models (ICGEM).

  11. From Drought to Recovery: a GRACE-Based Assessment of Groundwater Storage Variations in California

    Science.gov (United States)

    McEvoy, A.; Famiglietti, J. S.; Liu, P. W.; Reager, J. T., II

    2017-12-01

    The 2011-2015 drought in California was the most severe on record and significantly depleted state water reserves. However, after the consecutive wet winters of 2015-16 and 2016-17, water storage in reservoirs, soil, snowpack, and aquifers began recovering and the state government lifted the drought emergency for all California counties except four. But is the drought really "over"? Quantifiable metrics of groundwater storage are necessary to provide such evidence, yet in situ measurements are sparse at best. Here we holistically test whether California state water resources have fully recovered in the Sacramento, San Joaquin, and Tulare Lake basins of California, using remote sensing satellite observations, in situ measurements, and numerical models. Specifically, we partition water storage into four components of the terrestrial water cycle: soil moisture, snow water equivalent, surface water, and groundwater. We derive soil moisture and snow water equivalent from the North American Land Data Assimilation System (NLDAS) and we use the California Data Exchange Center (CDEC) network to measure in situ reservoir storage. To estimate changes in groundwater storage, we subtract these three components from the total water storage derived from the Gravity Recovery and Climate Experiment (GRACE) satellite. Preliminary results show that the groundwater storage plummeted to a record low during the 2011-2015 drought. The results also show a rapid recovery in total water storage from 2015-2017. Moreover, we find that groundwater accounts for, on average, 60% of the total water storage variations in the study basins. Our results hold social significance when placed in the context of arid California: Did the groundwater recover? Is this the largest recovery that California can expect? Finally, our results have implications for the utility of remote sensing to inform water resource management decisions.

  12. Understanding linkages between global climate indices and terrestrial water storage changes over Africa using GRACE products.

    Science.gov (United States)

    Anyah, R O; Forootan, E; Awange, J L; Khaki, M

    2018-09-01

    Africa, a continent endowed with huge water resources that sustain its agricultural activities is increasingly coming under threat from impacts of climate extremes (droughts and floods), which puts the very precious water resource into jeopardy. Understanding the relationship between climate variability and water storage over the continent, therefore, is paramount in order to inform future water management strategies. This study employs Gravity Recovery And Climate Experiment (GRACE) satellite data and the higher order (fourth order cumulant) statistical independent component analysis (ICA) method to study the relationship between terrestrial water storage (TWS) changes and five global climate-teleconnection indices; El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Madden-Julian Oscillation (MJO), Quasi-Biennial Oscillation (QBO) and the Indian Ocean Dipole (IOD) over Africa for the period 2003-2014. Pearson correlation analysis is applied to extract the connections between these climate indices (CIs) and TWS, from which some known strong CI-rainfall relationships (e.g., over equatorial eastern Africa) are found. Results indicate unique linear-relationships and regions that exhibit strong linkages between CIs and TWS. Moreover, unique regions having strong CI-TWS connections that are completely different from the typical ENSO-rainfall connections over eastern and southern Africa are also identified. Furthermore, the results indicate that the first dominant independent components (IC) of the CIs are linked to NAO, and are characterized by significant reductions of TWS over southern Africa. The second dominant ICs are associated with IOD and are characterized by significant increases in TWS over equatorial eastern Africa, while the combined ENSO and MJO are apparently linked to the third ICs, which are also associated with significant increase in TWS changes over both southern Africa, as well as equatorial eastern Africa. Copyright © 2018

  13. Dissatisfaction of Compact Picard Condition (CPC) with GRACE satellite data and its treatment by Generalized Tikhonov in Sobolev subspace

    Science.gov (United States)

    AllahTavakoli, Y.; Bagheri, H.; Safari, A.; Sharifi, M.

    2012-04-01

    This paper is mainly aiming to prove that the stripy noises in the map of earth's surface mass-density changes derived from GRACE Satellites gravimetry, is due to a dissatisfaction of Compact Picard Condition (CPC) with the GRACE data in the inversion of the Newton Integral Equation over the thin layer of earth; and hence the paper proposes the regularization strategies as efficient tools to treat the Ill-posedness and consequently to de-strip the data. First of all, we preferred to slightly modify the mathematical model of earth's surface mass-density changes developed creatively first by J. Wahr and et.al (1998), according to the all their previous assumptions plus taking into consideration the effect of the earth topography. By the modification we expect that some uncertainties in the prior model have been reduced to some extent. Then we analyzed the CPC on the model and we demonstrated how to perform Generalized Tikhonov regularization in Sobolev subspace for overcoming the instability of the problem. Then we applied the strategy in some simulations and case studies to validate our ideas. The simulations confirm that the stripy noises in the GRACE-derived map of the mass-density changes are due to the CPC dissatisfaction and furthermore the case studies show that Generalized Tikhonov regularization in Sobolev subspace is an influential filtering tool to de-strip the noisy data. Also, the case studies interestingly show that the effect of the topography is comparable to the effect of the load Love numbers on the Wahr's model; hence it may be taken into consideration when the load Love numbers have been taken into account.

  14. Assessment of the hydrologic setting and mass transport within Saharan and Arabian Aquifers using GRACE, geochemical, geophysical and subsurface data

    Science.gov (United States)

    Sultan, M.; Sturchio, N. C.; Ahmed, M.; Saleh, S.; Mohamed, A.; Abuabdullah, M. M.; Emil, M. K.; Bettadpur, S. V.; Save, H.; Fathy, K.; Chouinard, K.

    2016-12-01

    A better understanding of the hydrologic setting, mass transport, origin, evolution, utilization, sustainability, and paleo-climatic recharge conditions of Saharan and Arabian aquifers was achieved by integrating observation from monthly (04/2002 to 03/2016) Gravity Recovery and Climate Experiment (GRACE)-derived Terrestrial Water Storage (TWS) from multiple GRACE solutions (mascons and spherical harmonic fields) with others from geochemical (solute chemistry), isotopic (O, H, Sr), geochronologic (Chlorine-36, Krypton-81), geophysical (aerogravity and aeromagnetic), and subsurface data. The investigated aquifers are: (1) Nubian Sandstone Aquifer System (NSAS; area: 2×106 km2) in northeast Africa and, (2) Mega Aquifer System (MAS; area: 1.1×106 km2) in Arabia. Our findings indicate the NSAS and MAS were largely recharged in previous wet climatic Pleistocene periods, as evidenced by the groundwater ages (up to 1 million years), yet they receive modest local recharge during interleaving dry periods in areas of relatively high (≥ 20 mm/yr) precipitation. In Sudan and Chad (southern NSAS), the average annual precipitation (AAP) is 95 mm/yr and the recharge is estimated at 3.2 x 109 m3/yr ( 7% of AAP); in the southwest parts of the MAS, the recharge at the foothills of the Red Sea mountains is 1.8 x 109 m3/yr (10% of AAP). Uplifts and/or shear zones orthogonal to groundwater flow impede the south to north flow in the NSAS as evidenced by the large differences in GRACE-derived TWS trends, groundwater ages, and isotopic compositions on either side of the east-west trending Uweinat-Aswan uplift. Similarly west to east groundwater flow in the MAS is impeded and impounded up-gradient from the N-S and/or NW-SE trending basement structures, reactivated during Red Sea opening. Shear zones subparallel to groundwater flow act as preferred flow pathways, as is the case with the NE-SW trending Pelusium shear zone which channels groundwater from the Kufra sub-basin (Libya

  15. A New Model of the Mean Albedo of the Earth: Estimation and Validation from the GRACE Mission and SLR Satellites.

    Science.gov (United States)

    Deleflie, F.; Sammuneh, M. A.; Coulot, D.; Pollet, A.; Biancale, R.; Marty, J. C.

    2017-12-01

    This talk provides new results of a study that we began last year, and that was the subject of a poster by the same authors presented during AGU FM 2016, entitled « Mean Effect of the Albedo of the Earth on Artificial Satellite Trajectories: an Update Over 2000-2015. »The emissivity of the Earth, split into a part in the visible domain (albedo) and the infrared domain (thermic emissivity), is at the origin of non gravitational perturbations on artificial satellite trajectories. The amplitudes and periods of these perturbations can be investigated if precise orbits can be carried out, and reveal some characteristics of the space environment where the satellite is orbiting. Analyzing the perturbations is, hence, a way to characterize how the energy from the Sun is re-emitted by the Earth. When led over a long period of time, such an approach enables to quantify the variations of the global radiation budget of the Earth.Additionally to the preliminary results presented last year, we draw an assessment of the validity of the mean model based on the orbits of the GRACE missions, and, to a certain extent, of some of the SLR satellite orbits. The accelerometric data of the GRACE satellites are used to evaluate the accuracy of the models accounting for non gravitational forces, and the ones induced by the albedo and the thermic emissivity in particular. Three data sets are used to investigate the mean effects on the orbit perturbations: Stephens tables (Stephens, 1980), ECMWF (European Centre for Medium-Range Weather Forecasts) data sets and CERES (Clouds and the Earth's Radiant Energy System) data sets (publickly available). From the trajectography point of view, based on post-fit residual analysis, we analyze what is the data set leading to the lowest residual level, to define which data set appears to be the most suitable one to derive a new « mean albedo model » from accelerometric data sets of the GRACE mission. The period of investigation covers the full GRACE

  16. Antoine Ó Flatharta’s Elviad: from Grásta i Meiriceá to Grace in America

    OpenAIRE

    John L. Murphy

    2006-01-01

    Antoine Ó Flatharta bilingually charts media-saturated global impacts upon Galway’s Gaelic-speakers. His play in Irish,Grásta i Meiriceá (1990) features two young Irishmen who journey by bus on a pilgrimage to Elvis’ Graceland. In its 1993 English adaptation, Grace in America, the pair meets relatives who emigrated to 1940s Buffalo. Reading these plays by applying Seamus Deane’s “primordial nomination,” Edward Said’s “cartographical impulse,” Declan Kiberd’s “spiritual tourism,” and socioling...

  17. Predictive values of D-dimer assay, GRACE scores and TIMI scores for adverse outcome in patients with non-ST-segment elevation myocardial infarction

    Science.gov (United States)

    Satilmisoglu, Muhammet Hulusi; Ozyilmaz, Sinem Ozbay; Gul, Mehmet; Ak Yildirim, Hayriye; Kayapinar, Osman; Gokturk, Kadir; Aksu, Huseyin; Erkanli, Korhan; Eksik, Abdurrahman

    2017-01-01

    Purpose To determine the predictive values of D-dimer assay, Global Registry of Acute Coronary Events (GRACE) and Thrombolysis in Myocardial Infarction (TIMI) risk scores for adverse outcome in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Patients and methods A total of 234 patients (mean age: 57.2±11.7 years, 75.2% were males) hospitalized with NSTEMI were included. Data on D-dimer assay, GRACE and TIMI risk scores were recorded. Logistic regression analysis was conducted to determine the risk factors predicting increased mortality. Results Median D-dimer levels were 349.5 (48.0–7,210.0) ng/mL, the average TIMI score was 3.2±1.2 and the GRACE score was 90.4±27.6 with high GRACE scores (>118) in 17.5% of patients. The GRACE score was correlated positively with both the D-dimer assay (r=0.215, P=0.01) and TIMI scores (r=0.504, P=0.000). Multivariate logistic regression analysis revealed that higher creatinine levels (odds ratio =18.465, 95% confidence interval: 1.059–322.084, P=0.046) constituted the only significant predictor of increased mortality risk with no predictive values for age, D-dimer assay, ejection fraction, glucose, hemoglobin A1c, sodium, albumin or total cholesterol levels for mortality. Conclusion Serum creatinine levels constituted the sole independent determinant of mortality risk, with no significant values for D-dimer assay, GRACE or TIMI scores for predicting the risk of mortality in NSTEMI patients. PMID:28408834

  18. Identification of Outliers in Grace Data for Indo-Gangetic Plain Using Various Methods (Z-Score, Modified Z-score and Adjusted Boxplot) and Its Removal

    Science.gov (United States)

    Srivastava, S.

    2015-12-01

    Gravity Recovery and Climate Experiment (GRACE) data are widely used for the hydrological studies for large scale basins (≥100,000 sq km). GRACE data (Stokes Coefficients or Equivalent Water Height) used for hydrological studies are not direct observations but result from high level processing of raw data from the GRACE mission. Different partner agencies like CSR, GFZ and JPL implement their own methodology and their processing methods are independent from each other. The primary source of errors in GRACE data are due to measurement and modeling errors and the processing strategy of these agencies. Because of different processing methods, the final data from all the partner agencies