WorldWideScience

Sample records for balance mass

  1. Greenland Ice Sheet Mass Balance

    Science.gov (United States)

    Reeh, N.

    1984-01-01

    Mass balance equation for glaciers; areal distribution and ice volumes; estimates of actual mass balance; loss by calving of icebergs; hydrological budget for Greenland; and temporal variations of Greenland mass balance are examined.

  2. Mass balance assessment using GPS

    Science.gov (United States)

    Hulbe, Christina L.

    1993-01-01

    Mass balance is an integral part of any comprehensive glaciological investigation. Unfortunately, it is hard to determine at remote locations where there is no fixed reference. The Global Positioning System (GPS) offers a solution. Simultaneous GPS observations at a known location and the remote field site, processed differentially, will accurately position the camp site. From there, a monument planted in the firn atop the ice can also be accurately positioned. Change in the monument's vertical position is a direct indicator of ice thickness change. Because the monument is not connected to the ice, its motion is due to both mass balance change and to the settling of firn as it densifies into ice. Observations of relative position change between the monument and anchors at various depths within the firn are used to remove the settling effect. An experiment to test this method has begun at Byrd Station on the West Antarctic Ice Sheet and the first epoch of observations was made. Analysis indicates that positioning errors will be very small. It appears likely that the largest errors involved with this technique will arise from ancillary data needed to determine firn settling.

  3. 14 CFR 23.659 - Mass balance.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Mass balance. 23.659 Section 23.659 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... Surfaces § 23.659 Mass balance. The supporting structure and the attachment of concentrated mass...

  4. 14 CFR 29.659 - Mass balance.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Mass balance. 29.659 Section 29.659... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Rotors § 29.659 Mass balance. (a) The rotor... flutter at any speed up to the maximum forward speed. (b) The structural integrity of the mass...

  5. 14 CFR 27.659 - Mass balance.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Mass balance. 27.659 Section 27.659... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Rotors § 27.659 Mass balance. (a) The rotors... flutter at any speed up to the maximum forward speed. (b) The structural integrity of the mass...

  6. Reanalysing glacier mass balance measurement series

    OpenAIRE

    Zemp, M.; E. Thibert; Huss, M.; Stumm, D.; Rolstad Denby, C.; Nuth, C.; S. U. Nussbaumer; G. Moholdt; A. Mercer; Mayer, C.; Joerg, P. C.; P. Jansson; B. Hynek; Fischer, A.; Escher-Vetter, H.

    2013-01-01

    Glacier-wide mass balance has been measured for more than sixty years and is widely used as an indicator of climate change and to assess the glacier contribution to runoff and sea level rise. Until recently, comprehensive uncertainty assessments have rarely been carried out and mass balance data have often been applied using rough error estimation or without consideration of errors. In this study, we propose a framework for reanalysing glacier mass balance series that includes conceptual and ...

  7. Mass balance gradients and climatic change

    OpenAIRE

    Oerlemans, J.; Hoogendoorn, N.C.

    1989-01-01

    It is generally assumed that the mass-balance gradient on glaciers is more or less conserved under climatic change. In studies of the dynamic response of glaciers to climatic change, one of the following assumptions is normally made: (i) the mass-balance perturbation is independent of altitude or (ii) the mass-balance profile does not change - it simply shifts up and down. Observational evidence for such an approach is not convincing; on some glaciers the inter-annual changes in mass balance ...

  8. On the Mass Balance of Asphaltene Precipitation

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Lira-Galeana, C.; Stenby, Erling Halfdan

    2001-01-01

    In the evaluation of experimental data as well as in calculation of phase equilibria the necessity of the application of mass balances is obvious. In the case of asphaltenes the colloidal nature of these compounds may highly affect the mass balance. In the present paper several experiments are pe...

  9. Surface melt dominates Alaska glacier mass balance

    Science.gov (United States)

    Larsen Chris F; Burgess, E; Arendt, A.A.; O'Neel, Shad; Johnson, A.J.; Kienholz, C.

    2015-01-01

    Mountain glaciers comprise a small and widely distributed fraction of the world's terrestrial ice, yet their rapid losses presently drive a large percentage of the cryosphere's contribution to sea level rise. Regional mass balance assessments are challenging over large glacier populations due to remote and rugged geography, variable response of individual glaciers to climate change, and episodic calving losses from tidewater glaciers. In Alaska, we use airborne altimetry from 116 glaciers to estimate a regional mass balance of −75 ± 11 Gt yr−1 (1994–2013). Our glacier sample is spatially well distributed, yet pervasive variability in mass balances obscures geospatial and climatic relationships. However, for the first time, these data allow the partitioning of regional mass balance by glacier type. We find that tidewater glaciers are losing mass at substantially slower rates than other glaciers in Alaska and collectively contribute to only 6% of the regional mass loss.

  10. Mass-balance parameters derived from a synthetic network of mass-balance glaciers

    OpenAIRE

    Machguth, Horst; Haeberli, Wilfried; Paul, Frank

    2012-01-01

    Glacier mass-balance parameters such as the equilibrium-line altitude (ELA) play an important role when working with large glacier samples. While the number of observational mass-balance series to derive such parameters is limited, more and more modeled data are becoming available. Here we explore the possibilities of analyzing such ‘synthetic’ mass-balance data with respect to mass-balance parameters. A simplified energy-balance model is driven by bias-corrected regional climate model output...

  11. Miniature Piezoelectric Macro-Mass Balance

    Science.gov (United States)

    Sherrit, Stewart; Trebi-Ollennu, Ashitey; Bonitz, Robert G.; Bar-Cohen, Yoseph

    2010-01-01

    Mass balances usually use a strain gauge that requires an impedance measurement and is susceptible to noise and thermal drift. A piezoelectric balance can be used to measure mass directly by monitoring the voltage developed across the piezoelectric balance, which is linear with weight or it can be used in resonance to produce a frequency change proportional to the mass change (see figure). The piezoelectric actuator/balance is swept in frequency through its fundamental resonance. If a small mass is added to the balance, the resonance frequency shifts down in proportion to the mass. By monitoring the frequency shift, the mass can be determined. This design allows for two independent measurements of mass. Additionally, more than one sample can be verified because this invention allows for each sample to be transported away from the measuring device upon completion of the measurement, if required. A piezoelectric actuator, or many piezoelectric actuators, was placed between the collection plate of the sampling system and the support structure. As the sample mass is added to the plate, the piezoelectrics are stressed, causing them to produce a voltage that is proportional to the mass and acceleration. In addition, a change in mass delta m produces a change in the resonance frequency with delta f proportional to delta m. In a microgravity environment, the spacecraft could be accelerated to produce a force on the piezoelectric actuator that would produce a voltage proportional to the mass and acceleration. Alternatively, the acceleration could be used to force the mass on the plate, and the inertial effects of the mass on the plate would produce a shift in the resonance frequency with the change in frequency related to the mass change. Three prototypes of the mass balance mechanism were developed. These macro-mass balances each consist of a solid base and an APA 60 Cedrat flextensional piezoelectric actuator supporting a measuring plate. A similar structure with 3 APA

  12. Greenland mass balance from GRACE

    OpenAIRE

    Velicogna, I.; Wahr, J.

    2005-01-01

    We use 22 monthly GRACE (Gravity Recovery and Climate Experiment) gravity fields to estimate the linear trend in Greenland ice mass during 2002-2004. We recover a decrease in total ice mass of 82 ± 28 km3 of ice per year, consistent with estimates from other techniques. Our uncertainty estimate is dominated by the effects of GRACE measurement errors and errors in our post glacial rebound (PG) correction. The main advantages of GRACE are that it is sensitive to the entire ice sheet, and that i...

  13. Greenland ice sheet mass balance: a review

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Aschwanden, Andy; Bjørk, Anders A.;

    2015-01-01

    Over the past quarter of a century the Arctic has warmed more than any other region on Earth, causing a profound impact on the Greenland ice sheet (GrIS) and its contribution to the rise in global sea level. The loss of ice can be partitioned into processes related to surface mass balance...

  14. Composting: Mass Balances and Product Quality

    DEFF Research Database (Denmark)

    Boldrin, Alessio; Christensen, Thomas Højlund; Körner, I.;

    2011-01-01

    While the basic processes involved in composting of waste are described in Chapter 9.1 and the main composting technologies are presented in Chapter 9.2, this chapter focuses on mass balances, environmental emissions, unit process inventories and the quality of the compost produced. Understanding...

  15. Anaerobic Digestion: Mass Balances and Products

    DEFF Research Database (Denmark)

    Møller, Jacob; Christensen, Thomas Højlund; Jansen, Jes la Cour

    2011-01-01

    While the basic processes involved in anaerobic digestion of waste are described in Chapter 9.4 and the main digestion technologies are presented in Chapter 9.5, this chapter focuses on mass balances, gas production and energy aspects, environmental emissions and unit process inventories...

  16. Quantifying mass balance processes on the Southern Patagonia Icefield

    DEFF Research Database (Denmark)

    Schaefer, M.; Machguth, Horst; Falvey, M.;

    2014-01-01

    We present surface mass balance simulations of the Southern Patagonia Icefield driven by downscaled reanalysis data. The simulations were validated and interpreted using geodetic mass balances, measured point balances and a complete velocity field of 5 the Icefield from spring 2004. The high...... measured accumulation of snow as well as the high measured ablation is reproduced by the model. The overall modeled surface mass balance was positive and increasing during 1975–2011. Subtracting the surface mass balance from geodetic balances, calving fluxes were inferred. Mass losses of the SPI due to...... spatially distributed accumulation measurements can help to reduce the uncertainties of the different terms in the mass balance of the Southern Patagonia Icefield....

  17. Uncertainties and re-analysis of glacier mass balance measurements

    OpenAIRE

    Zemp, M.; E. Thibert; Huss, M.; Stumm, D.; Rolstad Denby, C.; Nuth, C.; S. U. Nussbaumer; G. Moholdt; A. Mercer; Mayer, C.; Joerg, P. C.; P. Jansson; B. Hynek; Fischer, A.; Escher-Vetter, H.

    2013-01-01

    Glacier-wide mass balance has been measured for more than sixty years and is widely used as an indicator of climate change and to assess the glacier contribution to runoff and sea level rise. Until present, comprehensive uncertainty assessments have rarely been carried out and mass balance data have often been applied using rough error estimation or without error considerations. In this study, we propose a framework for re-analyzing glacier mass balance series including conceptual and ...

  18. A nitrogen mass balance for California

    Science.gov (United States)

    Liptzin, D.; Dahlgren, R. A.

    2010-12-01

    Human activities have greatly altered the global nitrogen cycle and these changes are apparent in water quality, air quality, ecosystem and human health. However, the relative magnitude of the sources of new reactive nitrogen and the fate of this nitrogen is not well established. Further, the biogeochemical aspects of the nitrogen cycle are often studied in isolation from the economic and social implications of all the transformations of nitrogen. The California Nitrogen Assessment is an interdisciplinary project whose aim is evaluating the current state of nitrogen science, practice, and policy in the state of California. Because of the close proximity of large population centers, highly productive and diverse agricultural lands and significant acreage of undeveloped land, California is a particularly interesting place for this analysis. One component of this assessment is developing a mass balance of nitrogen as well as identifying gaps in knowledge and quantifying uncertainty. The main inputs of new reactive nitrogen to the state are 1) synthetic nitrogen fertilizer, 2) biological nitrogen fixation, and 3) atmospheric nitrogen deposition. Permanent losses of nitrogen include 1) gaseous losses (N2, N2O, NHx, NOy), 2) riverine discharge, 3) wastewater discharge to the ocean, and 4) net groundwater recharge. A final term is the balance of food, feed, and fiber to support the human and animal populations. The largest input of new reactive nitrogen to California is nitrogen fertilizer, but both nitrogen fixation and atmospheric deposition contribute significantly. Non-fertilizer uses, such as the production of nylon and polyurethane, constitutes about 5% of the synthetic N synthesized production. The total nitrogen fixation in California is roughly equivalent on the 400,000 ha of alfalfa and the approximately 40 million ha of natural lands. In addition, even with highly productive agricultural lands, the large population of livestock, in particular dairy cows

  19. Quantifying mass balance processes on the Southern Patagonia Icefield

    DEFF Research Database (Denmark)

    Schaefer, M.; Machguth, Horst; Falvey, M.;

    2015-01-01

    We present surface mass balance simulations of the Southern Patagonia Icefield (SPI) driven by downscaled reanalysis data. The simulations were evaluated and interpreted using geodetic mass balances, measured point balances and a complete velocity field of the icefield for spring 2004. The high...... measured accumulation of snow of up to 15.4m w.e. yr(-1) (meters water equivalent per year) as well as the high measured ablation of up to 11m w.e. yr(-1) is reproduced by the model. The overall modeled surface mass balance was positive and increasing during 1975-2011. Subtracting the surface mass balance...... from geodetic balances, calving fluxes were inferred. Mass losses of the SPI due to calving were strongly increasing from 1975-2000 to 2000-2011 and higher than losses due to surface melt. Calving fluxes were inferred for the individual glacier catchments and compared to fluxes estimated from velocity...

  20. Variability of surface mass balance in the Mizuho Plateau, Antarctica

    OpenAIRE

    Kazuhide, SATOW

    1985-01-01

    On the basis of the data of surface mass balance along the traverse routes in 1968-1983,mean and variation of the annual balance were obtained in the Mizuho Plateau, Antarctica. A year-to-year variation of the surface mass balance showed a general increase during the period of the measurement. The climatic effect and the effect of surface microrelief, such as sastrugi and dunes, on the mass balance variability were assessed. The former prevailed in a high accumulation zone of the coastal regi...

  1. Surface Mass Balance of the Columbia Glacier, Alaska, 1978 and 2010 Balance Years

    Science.gov (United States)

    O'Neel, Shad

    2012-01-01

    Although Columbia Glacier is one of the largest sources of glacier mass loss in Alaska, surface mass balance measurements are sparse, with only a single data set available from 1978. The dearth of surface mass-balance data prohibits partitioning of the total mass losses between dynamics and surface forcing; however, the accurate inclusion of calving glaciers into predictive models requires both dynamic and climatic forcing of total mass balance. During 2010, the U.S. Geological Survey collected surface balance data at several locations distributed over the surface of Columbia Glacier to estimate the glacier-wide annual balance for balance year 2010 using the 2007 area-altitude distribution. This report also summarizes data collected in 1978, calculates the 1978 annual surface balance, and uses these observations to constrain the 2010 values, particularly the shape of the balance profile. Both years exhibit balances indicative of near-equilibrium surface mass-balance conditions, and demonstrate the importance of dynamic processes during the rapid retreat.

  2. Mass balance and exergy analysis of a fast pyrolysis system

    Science.gov (United States)

    Mass balance closure and exergetic efficiency is evaluated for a bench scale fast pyrolysis system. The USDA Agricultural Research Service (ARS) has developed this system for processing energy crops and agricultural residues for bio-oil (pyrolysis oil or pyrolysis liquids) production. Mass balance c...

  3. Evapotranspiration: Mass balance measurements compared with flux estimation methods

    Science.gov (United States)

    Evapotranspiration (ET) may be measured by mass balance methods and estimated by flux sensing methods. The mass balance methods are typically restricted in terms of the area that can be represented (e.g., surface area of weighing lysimeter (LYS) or equivalent representative area of neutron probe (NP...

  4. Mass and heat balance approach for oil sand flowsheets

    Energy Technology Data Exchange (ETDEWEB)

    Salama, A.I.A. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2009-07-01

    Plant flowsheet mass balance is carried out in many industrial applications to evaluate overall plant performance and to optimize plant recoveries. This information is necessary for improving the economics of the operation and improving profitability. Flowsheet mass balance begins with the collection of plant stream samples using well-known sampling schemes. Stream samples collected using ASTM sampling standards are then analyzed using ASTM analytical techniques to characterize stream components which often contain sampling and analytical errors. The paper presented an approach for oil sands flowsheet mass and heat balance where different objective functions were presented depending on the nature of the stream error distributions. Hot water or steam is used to heat plant streams in oil sands extraction and froth treatment plants. As such, an approach is needed to integrate mass and heat balance. The mass and heat balance approach proposed in this paper integrated mass and heat balance and optimized the deviations/errors between the raw/observed and estimated data sets. The estimated data set was constrained to satisfy mass and heat balance conditions around the flowsheet internal nodes. Stream normalization and stream normalization conditions were forced. The relationship between the flowsheet independent, dependent, and reference streams were identified. The number of the independent stream mass splits was expressed in terms of the number of streams, number of nodes, and number of reference streams. 9 refs., 3 tabs., 2 figs.

  5. Juneau Icefield Mass Balance Program 1946–2011

    Directory of Open Access Journals (Sweden)

    M. Pelto

    2013-05-01

    Full Text Available The mass balance records of the Lemon Creek Glacier and Taku Glacier observed by the Juneau Icefield Research Program are the longest continuous glacier mass balance data sets in North America. On Taku Glacier annual mass balance averaged +0.40 m a−1 from 1946–1985 and −0.08 m a−1 from 1986–2011. The recent mass balance decline has resulted in the cessation of the long term thickening of the glacier. Mean annual mass balance on Lemon Creek Glacier has declined from −0.30 m a−1 for the 1953–1985 period to −0.60 m a−1 during the 1986–2011 period. The overall mass balance change is −26.6 m water equivalent, a 29 m of ice thinning over the 55 yr. Probing transects above the transient snow line (TSL indicate a consistent balance gradient from year to year. Observations of the rate of summer TSL rise on Lemon Creek and Taku Glacier indicate a comparatively consistent rate of 3.8 to 4.1 m d−1. The relationship between TSL on Lemon Creek and Taku Glacier to other Juneau Icefield glaciers, Norris, Mendenhall, Herbert, and Eagle, is strong with correlations exceeding 0.82 in all cases. doi:10.5065/D6NZ85N3

  6. A portable, automated, inexpensive mass and balance calibration system

    International Nuclear Information System (INIS)

    Reliable mass measurements are essential for a nuclear production facility or process control laboratory. DOE Order 5630.2 requires that traceable standards be used to calibrate and monitor equipment used for nuclear material measurements. To ensure the reliability of mass measurements and to comply with DOE traceability requirements, a portable, automated mass and balance calibration system is used at the Savannah River Plant. Automation is achieved using an EPSON HX-20 notebook computer, which can be operated via RS232C interfacing to electronic balances or function with manual data entry if computer interfacing is not feasible. This economical, comprehensive, user-friendly system has three main functions in a mass measurement control program (MMCP): balance certification, calibration of mass standards, and daily measurement of traceable standards. The balance certification program tests for accuracy, precision, sensitivity, linearity, and cornerloading versus specific requirements. The mass calibration program allows rapid calibration of inexpensive mass standards traceable to certified Class S standards. This MMCP permits daily measurement of traceable standards to monitor the reliability of balances during routine use. The automated system verifies balance calibration, stores results for future use, and provides a printed control chart of the stored data. Another feature of the system permits three different weighing routines that accommodate their need for varying degrees of reliability in routine weighing operations

  7. Open complex-balanced mass action chemical reaction networks

    NARCIS (Netherlands)

    Rao, Shodhan; van der Schaft, Arjan; Jayawardhana, Bayu

    2014-01-01

    We consider open chemical reaction networks, i.e. ones with inflows and outflows. We assume that all the inflows to the network are constant and all outflows obey the mass action kinetics rate law. We define a complex-balanced open reaction network as one that admits a complex-balanced steady state.

  8. Nitrate mass balance in the Padež stream watershed

    OpenAIRE

    Česnik, Katarina

    2014-01-01

    Graduation thesis analyzes changes in nitrate mass balance in a forested watersheds. The nitrate mass balance changes occur manly because of hydrological and biogeochemical mechanisms. The studied area, the Padež stream watershed, is mainly covered with forest. Between years 2006 and 2007 the hydrometeorological conditions and streamwater chemistry of Padež stream were continuously monitored. The differences in streamwater nitrate concentrations and nitrate concentrations in precipitations an...

  9. Quantifying mass balance processes on the Southern Patagonia Icefield

    OpenAIRE

    Schaefer, M.; Machguth, H.; M. Falvey; Casassa, G.; Rignot, E

    2015-01-01

    We present surface mass balance simulations of the Southern Patagonia Icefield (SPI) driven by downscaled reanalysis data. The simulations were evaluated and interpreted using geodetic mass balances, measured point balances and a complete velocity field of the icefield for spring 2004. The high measured accumulation of snow of up to 15.4 m w.e. yr−1 (meters water equivalent per year) as well as the high measured ablation of up to 11 m w.e. yr−1 is reproduced by the model. Th...

  10. A Simple Watt Balance for the Absolute Determination of Mass

    Science.gov (United States)

    Quinn, Terry; Quinn, Lucas; Davis, Richard

    2013-01-01

    A watt balance is an electromechanical device that allows a mass to be determined in terms of measurable electrical and mechanical quantities, themselves traceable to the fundamental constants of physics. International plans are well advanced to redefine the unit of mass, the kilogram, in terms of a fixed numerical value for the Planck constant. A…

  11. Mass balance at partial run of quartzite carbothermal reduction

    Directory of Open Access Journals (Sweden)

    J. Węgrzyn

    2016-04-01

    Full Text Available Mass balance for the process of incomplete carbothermal reduction of SiO2 to SiC thermogravimetric studies was presented. Tests were performed for the molar ratio of C/SiO2 = 3 at a temperature of 1 500 °C under an argon flow in the range from 0,1 to 3,4 dm3/min. Mass balance includes the loss due to escape of SiO and the mass of reactants C and SiO2 due to stopping the reaction. The weight gain of Al2O3 crucible was found and also the formation of crust layer on the surface of the samples. The crucible weight gain and the weight of crust layer created were taken into account in mass balance.

  12. 50 years of mass balance observations at Vernagtferner, Eastern Alps

    Science.gov (United States)

    Braun, Ludwig; Mayer, Christoph

    2016-04-01

    The determination and monitoring of the seasonal and annual glacier mass balances of Vernagtferner, Austria, started in 1964 by the Commission of Glaciology, Bavarian Academy of Sciences. Detailed and continuous climate- and runoff measurements complement this mass balance series since 1974. Vernagtferner attracted the attention of scientists since the beginning of the 17th century due to its rapid advances and the resulting glacier lake outburst floods in the Ötztal valley. This is one reason for the first photogrammetric survey in 1889, which was followed by frequent topographic surveys, adding up to more than ten digital elevation models of the glacier until today. By including the known maximum glacier extent at the end of the Little Ice Age in 1845, the geodetic glacier volume balances cover a time span of almost 170 years. The 50 years of glacier mass balance and 40 years of water balance in the drainage basin are therefore embedded in a considerably longer period of glacier evolution, allowing an interpretation within an extended frame of climatology and ice dynamics. The direct mass balance observations cover not only the period of alpine-wide strong glacier mass loss since the beginning of the 1990s. The data also contain the last period of glacier advances between 1970 and 1990. The combination of the observed surface mass exchange and the determined periodic volumetric changes allows a detailed analysis of the dynamic reaction of the glacier over the period of half a century. The accompanying meteorological observations are the basis for relating these reactions to the climatic changes during this period. Vernagtferner is therefore one of the few glaciers in the world, where a very detailed glacier-climate reaction was observed for many decades and can be realistically reconstructed back to the end of the Little Ice Age.

  13. The climatic mass balance of Svalbard glaciers: a 10-year simulation with a coupled atmosphere-glacier mass balance model

    Science.gov (United States)

    Aas, Kjetil S.; Dunse, Thorben; Collier, Emily; Schuler, Thomas V.; Berntsen, Terje K.; Kohler, Jack; Luks, Bartłomiej

    2016-05-01

    In this study we simulate the climatic mass balance of Svalbard glaciers with a coupled atmosphere-glacier model with 3 km grid spacing, from September 2003 to September 2013. We find a mean specific net mass balance of -257 mm w.e. yr-1, corresponding to a mean annual mass loss of about 8.7 Gt, with large interannual variability. Our results are compared with a comprehensive set of mass balance, meteorological, and satellite measurements. Model temperature biases of 0.19 and -1.9 °C are found at two glacier automatic weather station sites. Simulated climatic mass balance is mostly within about 100 mm w.e. yr-1 of stake measurements, and simulated winter accumulation at the Austfonna ice cap shows mean absolute errors of 47 and 67 mm w.e. yr-1 when compared to radar-derived values for the selected years 2004 and 2006. Comparison of modeled surface height changes from 2003 to 2008, and satellite altimetry reveals good agreement in both mean values and regional differences. The largest deviations from observations are found for winter accumulation at Hansbreen (up to around 1000 mm w.e. yr-1), a site where sub-grid topography and wind redistribution of snow are important factors. Comparison with simulations using 9 km grid spacing reveal considerable differences on regional and local scales. In addition, 3 km grid spacing allows for a much more detailed comparison with observations than what is possible with 9 km grid spacing. Further decreasing the grid spacing to 1 km appears to be less significant, although in general precipitation amounts increase with resolution. Altogether, the model compares well with observations and offers possibilities for studying glacier climatic mass balance on Svalbard both historically as well as based on climate projections.

  14. A reconciled estimate of ice-sheet mass balance

    DEFF Research Database (Denmark)

    Shepherd, Andrew; Ivins, Erik R; A, Geruo;

    2012-01-01

    We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good...... agreement between different satellite methods--especially in Greenland and West Antarctica--and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 ± 49, +14...... ± 43, -65 ± 26, and -20 ± 14 gigatonnes year(-1), respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year(-1) to the rate of global sea-level rise....

  15. Mass balance at partial run of quartzite carbothermal reduction

    OpenAIRE

    J. Węgrzyn

    2016-01-01

    Mass balance for the process of incomplete carbothermal reduction of SiO2 to SiC thermogravimetric studies was presented. Tests were performed for the molar ratio of C/SiO2 = 3 at a temperature of 1 500 °C under an argon flow in the range from 0,1 to 3,4 dm3/min. Mass balance includes the loss due to escape of SiO and the mass of reactants C and SiO2 due to stopping the reaction. The weight gain of Al2O3 crucible was found and also the formation of crust layer on the surface of the samples. T...

  16. A Reconciled Estimate of Ice-Sheet Mass Balance

    Science.gov (United States)

    Shepherd, Andrew; Ivins, Erik R.; Geruo, A.; Barletta, Valentia R.; Bentley, Mike J.; Bettadpur, Srinivas; Briggs, Kate H.; Bromwich, David H.; Forsberg, Rene; Galin, Natalia; Horwath, Martin; Jacobs, Stan; Joughin, Ian; King, Matt A.; Lenaerts, Jan T. M.; Li, Jilu; Ligtenberg, Stefan R. M.; Luckman, Adrian; Luthcke, Scott B.; McMillan, Malcolm; Meister, Rakia; Milne, Glenn; Mouginot, Jeremie; Muir, Alan; Nicolas,Julien P.; Paden, John; Payne, Antony J.; Pritchard, Hamish; Rignot, Eric; Rott, Helmut; Sorensen, Louise Sandberg; Scambos, Ted A.; Yi, Dohngui; Zwally, H. Jay

    2012-01-01

    We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods-especially in Greenland and West Antarctica-and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 plus or minus 49, +14 plus or minus 43, -65 plus or minus 26, and -20 plus or minus 14 gigatonnes year(sup -1), respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 plus or minus 0.20 millimeter year(sup -1) to the rate of global sea-level rise.

  17. Effect of mass asymmetry on the mass dependence of balance energy

    OpenAIRE

    Goyal, Supriya

    2011-01-01

    We demonstrate the role of the mass asymmetry on the balance energy (Ebal) by studying asymmetric reactions throughout the periodic table and over entire colliding geometry. Our results, which are almost independent of the system size and as well as of the colliding geometries indicate a sizeable effect of the asymmetry of the reaction on the balance energy.

  18. Modeling energy and mass balance of Shallap Glacier, Peru

    Directory of Open Access Journals (Sweden)

    W. Gurgiser

    2013-11-01

    Full Text Available We calculated the distributed surface mass and energy balance of Shallap Glacier, Cordillera Blanca, Peru (9° S, 77° W, 4700–5700 m a.s.l., ~ 7 km2, on hourly time steps for two years (September 2006–August 2008 using a process-based model and meteorological measurements as input. Model parameter combinations were optimized against 21 temporal readings of 20 stakes in the ablation zone of the glacier. Uncertainty caused by model input parameters and parameterization schemes was estimated using a leave-one out cross-validation scheme, which yields values of root mean square deviation (RMSD of surface height change < 1 m (< 10% of the measured amplitude for all stakes. With the best parameter combination (smallest RMSD applied, the modeled annual surface mass balance of the glacier was −0.32 ± 0.4 m w.e. (water equivalent for September 2006–August 2007 and 0.51 ± 0.56 m w.e. for September 2007–August 2008. While the mass balance above 5000 m was similar in both years (Δ 0.33 ± 0.68 m w.e. due to similar annual sums of solid precipitation, a difference of 1.97 ± 0.68 m w.e. was calculated for the lower parts of the glacier. This difference is associated with more frequent occurrence of higher snow line altitudes during the first year, which was mainly caused by a higher fraction of liquid precipitation due to higher mean air temperatures. As the net shortwave budget was found to be the main source for ablation throughout the year at Shallap Glacier, lower surface albedo especially caused by lower solid precipitation amounts explains most of the difference in modeled ablation and mass balance between the two years.

  19. Towards remote monitoring of sub-seasonal glacier mass balance

    OpenAIRE

    Huss, Matthias; Sold, Leo; Hoelzle, Martin; Stokvis, Mazzal; Salzmann, Nadine; Farinotti Daniel; Zemp, Michael

    2013-01-01

    This study presents a method that allows continuous monitoring of mass balance for remote or inaccessible glaciers, based on repeated oblique photography. Hourly to daily pictures from two automatic cameras overlooking two large valley glaciers in the Swiss Alps are available for eight ablation seasons (2004–11) in total. We determine the fraction of snow-covered glacier surface from orthorectified and georeferenced images and combine this information with simple accumulation and melt modelli...

  20. Modeling energy and mass balance of Shallap Glacier, Peru

    Directory of Open Access Journals (Sweden)

    W. Gurgiser

    2013-08-01

    Full Text Available We calculated the distributed surface mass and energy balance of Shallap Glacier, Cordillera Blanca, Peru (9° S, 77° W, 4700–5700 m a.s.l., ∼ 7 km2 on hourly time steps for two years (September 2006–August 2008 using a process-based model and meteorological measurements as input. Model parameter combinations were optimized against 21 temporal readings of 20 stakes in the ablation zone of the glacier. Uncertainty caused by model input parameters and parameterization schemes was estimated using a leave-one-out cross-validation scheme and yields values of root mean square deviation (RMSD of surface height change < 1m (< 10% of the measured amplitude for all stakes. With the best parameter combination (smallest RMSD applied, the modeled annual surface mass balance of the glacier was −0.32 ± 0.4 m w.e. for September 2006–August 2007 and 0.51 ± 0.56 m w.e. for September 2007–August 2008. While the mass balance above 5000 m was similar in both years (Δ 0.35 ± 0.68 m w.e. due to similar annual sums of solid precipitation, a difference of ∼ 2 ± 0.68 m w.e. was calculated for the lower parts of the glacier. This difference is associated with more frequent occurrence of higher snow line altitudes during the first year, which was mainly caused by a higher fraction of liquid precipitation due to higher mean air temperatures. As the net shortwave budget was found to be the main source for ablation throughout the year at Shallap Glacier, lower surface albedo caused by higher snow line altitudes explains most of the difference in modeled ablation and mass balance between the two years.

  1. Hypsometric control on glacier mass balance sensitivity in Alaska

    Science.gov (United States)

    McGrath, D.; Sass, L.; Arendt, A. A.; O'Neel, S.; Kienholz, C.; Larsen, C.; Burgess, E. W.

    2015-12-01

    Mass loss from glaciers in Alaska is dominated by strongly negative surface balances, particularly on small, continental glaciers but can be highly variable from glacier to glacier. Glacier hypsometry can exert significant control on mass balance sensitivity, particularly if the equilibrium line altitude (ELA) is in a broad area of low surface slope. In this study, we explore the spatial variability in glacier response to future climate forcings on the basis of hypsometry. We first derive mass balance sensitivities (30-70 m ELA / 1° C and 40-90 m ELA / 50% decrease in snow accumulation) from the ~50-year USGS Benchmark glaciers mass balance record. We subsequently assess mean climate fields in 2090-2100 derived from the IPCC AR5/CMIP5 RCP 6.0 5-model mean. Over glaciers in Alaska, we find 2-4° C warming and 10-20% increase in precipitation relative to 2006-2015, but a corresponding 0-50% decrease in snow accumulation due to rising temperatures. We assess changes in accumulation area ratios (AAR) to a rising ELA using binned individual glacier hypsometries. For an ELA increase of 150 m, the mean statewide AAR drops by 0.45, representing a 70% reduction in accumulation area on an individual glacier basis. Small, interior glaciers are the primary drivers of this reduction and for nearly 25% of all glaciers, the new ELA exceeds the glacier's maximum elevation, portending eventual loss. The loss of small glaciers, particularly in the drier interior of Alaska will significantly modify streamflow properties (flashy hydrographs, earlier and reduced peak flows, increased interannual variability, warmer temperatures) with poorly understood downstream ecosystem and oceanographic impacts.

  2. Milligram mass metrology using an electrostatic force balance

    Science.gov (United States)

    Shaw, Gordon A.; Stirling, Julian; Kramar, John A.; Moses, Alexander; Abbott, Patrick; Steiner, Richard; Koffman, Andrew; Pratt, Jon R.; Kubarych, Zeina J.

    2016-10-01

    Although mass is typically defined within the International System of Units (SI) at the kilogram level, the pending SI redefinition provides an opportunity to realize mass at any scale using electrical metrology. We propose the use of an electromechanical balance to realize mass at the milligram level using SI electrical units. An integrated concentric-cylinder vacuum gap capacitor allows us to leverage the highly precise references available for capacitance, voltage and length to generate an electrostatic reference force. Weighing experiments performed on 1 mg and 20 mg artifacts show the same or lower uncertainty than similar experiments performed by subdividing the kilogram. The measurement is currently limited by the stability of the materials that compose the mass artifacts and the changes in adsorbed layers on the artifact surfaces as they are transferred from vacuum to air.

  3. The Ice Sheet Mass Balance Inter-comparison Exercise

    Science.gov (United States)

    Shepherd, A.; Ivins, E. R.

    2015-12-01

    Fluctuations in the mass of ice stored in Antarctica and Greenland are of considerable societal importance. The Ice Sheet Mass Balance Inter-Comparison Exercise (IMBIE) is a joint-initiative of ESA and NASA aimed at producing a single estimate of the global sea level contribution to polar ice sheet losses. Within IMBIE, estimates of ice sheet mass balance are developed from a variety of satellite geodetic techniques using a common spatial and temporal reference frame and a common appreciation of the contributions due to external signals. The project brings together the laboratories and space agencies that have been instrumental in developing independent estimates of ice sheet mass balance to date. In its first phase, IMBIE involved 27 science teams, and delivered a first community assessment of ice sheet mass imbalance to replace 40 individual estimates. The project established that (i) there is good agreement between the three main satellite-based techniques for estimating ice sheet mass balance, (ii) combining satellite data sets leads to significant improvement in certainty, (iii) the polar ice sheets contributed 11 ± 4 mm to global sea levels between 1992 and 2012, and (iv) that combined ice losses from Antarctica and Greenland have increased over time, rising from 10% of the global trend in the early 1990's to 30% in the late 2000's. Demand for an updated assessment has grown, and there are now new satellite missions, new geophysical corrections, new techniques, and new teams producing data. The period of overlap between independent satellite techniques has increased from 5 to 12 years, and the full period of satellite data over which an assessment can be performed has increased from 19 to 40 years. It is also clear that multiple satellite techniques are required to confidently separate mass changes associated with snowfall and ice dynamical imbalance - information that is of critical importance for climate modelling. This presentation outlines the approach

  4. Mass balance of the Lambert Glacier basin, East Antarctica

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Since it is the largest glacier system in Antarctica, the Lambert Glacier basin plays an important role in the mass balance of the overall Antarctic ice sheet. The observed data and shallow core studies from the inland traverse investigations in recent years show that there are noticeable differences in the distribution and variability of the snow accumulation rate between east and west sides. On the east side, the accumulation is higher on the average and has increased in the past decades, while on the west side it is contrary. The ice movement measurement and the ice flux calculation indicate that the ice velocity and the flux are larger in east than in west, meaning that the major part of mass supply for the glacier is from the east side. The mass budget estimate with the latest data gives that the integrated accumulation over the upstream area of the investigation traverse route is larger than the outflow ice flux by 13%, suggesting that the glacier basin is in a positive mass balance state and the ice thickness will increase if the present climate is keeping.

  5. Selenium mass balance in the Great Salt Lake, Utah

    Science.gov (United States)

    Diaz, X.; Johnson, W.P.; Naftz, D.L.

    2009-01-01

    A mass balance for Se in the south arm of the Great Salt Lake was developed for September 2006 to August 2007 of monitoring for Se loads and removal flows. The combined removal flows (sedimentation and volatilization) totaled to a geometric mean value of 2079??kg Se/yr, with the estimated low value being 1255??kg Se/yr, and an estimated high value of 3143??kg Se/yr at the 68% confidence level. The total (particulates + dissolved) loads (via runoff) were about 1560??kg Se/yr, for which the error is expected to be ?? 15% for the measured loads. Comparison of volatilization to sedimentation flux demonstrates that volatilization rather than sedimentation is likely the major mechanism of selenium removal from the Great Salt Lake. The measured loss flows balance (within the range of uncertainties), and possibly surpass, the measured annual loads. Concentration histories were modeled using a simple mass balance, which indicated that no significant change in Se concentration was expected during the period of study. Surprisingly, the measured total Se concentration increased during the period of the study, indicating that the removal processes operate at their low estimated rates, and/or there are unmeasured selenium loads entering the lake. The selenium concentration trajectories were compared to those of other trace metals to assess the significance of selenium concentration trends. ?? 2008 Elsevier B.V.

  6. Quantifying the Mass Balance of Ice Caps on Severnaya Zemlya, Russian High Arctic. I: Climate and Mass Balance of the Vavilov Ice Cap

    OpenAIRE

    Bassford, R. P.; Siegert, M.J.; Dowdeswell, J.A.; Oerlemans, J.; A. F. Glazovsky; Macheret, Y.Y.

    2006-01-01

    Due to their remote location within the Russian High Arctic, little is known about the mass balance of ice caps on Severnaya Zemlya now and in the past. Such information is critical, however, to building a global picture of the cryospheric response to climate change. This paper provides a numerical analysis of the climate and mass balance of the Vavilov Ice Cap on October Revolution Island. Mass balance model results are compared with available glaciological and climatological data. A referen...

  7. Global application of a surface mass balance model using gridded climate data

    OpenAIRE

    R. H. Giesen; Oerlemans, J.

    2012-01-01

    Global applications of surface mass balance models have large uncertainties, as a result of poor climate input data and limited availability of mass balance measurements. This study addresses several possible consequences of these limitations for the modelled mass balance. This is done by applying a simple surface mass balance model that only requires air temperature and precipitation as input data, to glaciers in different regions. In contrast to other models used in global applications...

  8. Calibration of a surface mass balance model for global-scale applications

    OpenAIRE

    R. H. Giesen; Oerlemans, J.

    2012-01-01

    Global applications of surface mass balance models have large uncertainties, as a result of poor climate input data and limited availability of mass balance measurements. This study addresses several possible consequences of these limitations for the modelled mass balance. This is done by applying a simple surface mass balance model that only requires air temperature and precipitation as input data, to glaciers in different regions. In contrast to other models used in global applications, thi...

  9. Towards a re-assessment of the surface mass balance of the Greenland ice sheet

    OpenAIRE

    van den Broeke M.; Ettema J.; van de Berg W. J.; van Meijgaard E.

    2009-01-01

    At present, the mass balance and especially the surface mass balance of the Greenland Ice Sheet (GrIS) are poorly known. Current methods to determine GrIS surface mass balance as well as the inherent uncertainties are discussed. Special emphasis is placed on the increasingly important role of regional atmospheric climate models, which explicitly calculate the individual components of the surface mass balance: (solid) precipitation, melt and subsequent runoff, sublimation/deposition and refree...

  10. Modelled climate sensitivity of the mass balance of Morteratschgletscher and its dependence on albedo parameterization

    NARCIS (Netherlands)

    Klok, E.J.; Oerlemans, J.

    2004-01-01

    This paper presents a study of the climate sensitivity of the mass balance of Morteratschgletscher in Switzerland, estimated from a two-dimensional mass balance model. Since the albedo scheme chosen is often the largest error source in mass balance models, we investigated the impact of using differe

  11. Calibration of a surface mass balance model for global-scale applications

    NARCIS (Netherlands)

    Giesen, R. H.; Oerlemans, J.

    2012-01-01

    Global applications of surface mass balance models have large uncertainties, as a result of poor climate input data and limited availability of mass balance measurements. This study addresses several possible consequences of these limitations for the modelled mass balance. This is done by applying a

  12. Balancing mass and momentum in the Local Group

    CERN Document Server

    Diaz, Jonathan D; Irwin, Mike; Belokurov, Vasily; Evans, Wyn

    2014-01-01

    In the rest frame of the Local Group (LG), the total momentum of the Milky Way (MW) and Andromeda (M31) should balance to zero. We use this fact to constrain new solutions for the solar motion with respect to the LG centre-of-mass, the total mass of the LG, and the individual masses of M31 and the MW. Using the set of remote LG galaxies at $>350$ kpc from the MW and M31, we find that the solar motion has amplitude $V_{\\odot}=299\\pm 15 {\\rm ~km~s^{-1}}$ in a direction pointing toward galactic longitude $l_{\\odot}=98.4^{\\circ}\\pm 3.6^{\\circ}$ and galactic latitude $b_{\\odot}=-5.9^{\\circ}\\pm 3.0^{\\circ}$. The velocities of M31 and the MW in this rest frame give a direct measurement of their mass ratio, for which we find $\\log_{10} (M_{\\rm M31}/M_{\\rm MW})=0.36 \\pm 0.29$. We combine these measurements with the virial theorem to estimate the total mass within the LG as $M_{\\rm LG}=(2.5\\pm 0.4)\\times 10^{12}~{\\rm M}_{\\odot}$. Our value for $M_{\\rm LG}$ is consistent with the sum of literature values for $M_{\\rm MW}...

  13. Energy and Mass Balance At Gran Campo Nevado, Patagonia, Chile

    Science.gov (United States)

    Schneider, C.; Kilian, R.; Casassa, G.

    The Gran Campo Nevado (GCN) Ice Cap on Peninsula Muñoz Gamero, Chile, is lo- cated in the southernmost part of the Patagonian Andes at 53S. It comprises an ice cap and numerous outlet glaciers which mostly end in proglacial lakes at sea level. The total ice covered area sums up to approximately 250 km2. GCN forms the only major ice body between the Southern Patagonian Icefield and the Street of Magallan. Its almost unique location in the zone of the all-year westerlies makes it a region of key interest in terms of glacier and climate change studies of the westwind zone of the Southern Hemisphere. Mean annual temperature of approximately +5C at sea level and high precipitation of about 8.000 mm per year lead to an extreme turn-over of ice mass from the accumulation area of the GCN Ice Cap to the ablation areas of the outlet glaciers. Since October 1999 an automated weather station (AWS) is run continuously in the area at Bahia Bahamondes for monitoring climate parameters. From February to April 2000 an additional AWS was operated on Glaciar Lengua a small outlet glacier of GCN to the north-west. Ablation has been measured at stakes during the same pe- riod. The aim of this study, was to obtain point energy and mass balance on Glaciar Lengua. The work was conducted as part of the international and interdisciplinary working group SGran Campo NevadoT and supported by the German Research Foun- & cedil;dation (DFG). Energy balance was calculated using the bulk approach formulas and calibrated to the measured ablation. It turns out, that sensible heat transfer is the major contribution to the energy balance. Since high cloud cover rates prevail, air tempera- ture is the key factor for the energy balance of the glacier. Despite high rain fall rates, energy input from rain fall is of only minor importance to the overall energy balance. From the energy balance computed, it was possible to derive summer-time degree-day factors for Glaciar Lengua. With data from the nearby

  14. Mass balance assessment for mercury in Lake Champlain

    Science.gov (United States)

    Gao, N.; Armatas, N.G.; Shanley, J.B.; Kamman, N.C.; Miller, E.K.; Keeler, G.J.; Scherbatskoy, T.; Holsen, T.M.; Young, T.; McIlroy, L.; Drake, S.; Olsen, Bill; Cady, C.

    2006-01-01

    A mass balance model for mercury in Lake Champlain was developed in an effort to understand the sources, inventories, concentrations, and effects of mercury (Hg) contamination in the lake ecosystem. To construct the mass balance model, air, water, and sediment were sampled as a part of this project and other research/monitoring projects in the Lake Champlain Basin. This project produced a STELLA-based computer model and quantitative apportionments of the principal input and output pathways of Hg for each of 13 segments in the lake. The model Hg concentrations in the lake were consistent with measured concentrations. Specifically, the modeling identified surface water inflows as the largest direct contributor of Hg into the lake. Direct wet deposition to the lake was the second largest source of Hg followed by direct dry deposition. Volatilization and sedimentation losses were identified as the two major removal mechanisms. This study significantly improves previous estimates of the relative importance of Hg input pathways and of wet and dry deposition fluxes of Hg into Lake Champlain. It also provides new estimates of volatilization fluxes across different lake segments and sedimentation loss in the lake. ?? 2006 American Chemical Society.

  15. Deducing high-altitude precipitation from glacier mass balance measurements

    Science.gov (United States)

    Giesen, Rianne H.; Immerzeel, Walter W.; Wanders, Niko

    2016-04-01

    The spatial distribution of precipitation in mountainous terrain is generally not well known due to underrepresentation of gauge observations at higher elevations. Precipitation tends to increase with elevation, but since observations are mainly performed in the valleys, the vertical precipitation gradient cannot be deduced from these measurements. Furthermore, the spatial resolution of gridded meteorological data is often too coarse to resolve individual mountain chains. Still, a reliable estimate of high-elevation precipitation is required for many hydrological applications. We present a method to determine the vertical precipitation gradient in mountainous terrain, making use of glacier mass balance observations. These measurements have the advantage that they provide a basin-wide precipitation estimate at high elevations. The precipitation gradient is adjusted until the solid precipitation over the glacier area combined with the calculated melt gives the measured annual glacier mass balance. Results for the glacierized regions in Central Europe and Scandinavia reveal spatially coherent patterns, with predominantly positive precipitation gradients ranging from -4 to +28 % (100 m)‑1. In some regions, precipitation amounts at high elevations are up to four times as large as in the valleys. A comparison of the modelled winter precipitation with observed snow accumulation on glaciers shows a good agreement. Precipitation measured at the few high-altitude meteorological stations is generally lower than our estimate, which may result from precipitation undercatch. Our findings will improve the precipitation forcing for glacier modelling and hydrological studies in mountainous terrain.

  16. Mass-balance model for predicting nitrate in ground water

    Science.gov (United States)

    Frimpter, Michael H.; Donohue, John J.; Rapacz, Michael V.

    1990-01-01

    A mass-balance accounting model can be used to guide the management of septic systems and fertilizers to control the degradation of ground-water quality in zones of an aquifer that contribute water to public-supply wells. The nitrate concentration of the mixture in the well can be predicted for steady-state conditions by calculating the concentration that results from the total weight of nitrogen and total volume of water entering the zone of contribution to the well. These calculations will allow water-quality managers to predict the nitrate concentrations that would be produced by different types and levels of development, and to plan development accordingly. Computations for different development schemes provide a technical basis for planners and managers to compare water-quality effects and to select alternatives that limit nitrate concentration in wells.

  17. Maintaining Atmospheric Mass and Water Balance Within Reanalysis

    Science.gov (United States)

    Takacs, Lawrence L.; Suarez, Max; Todling, Ricardo

    2015-01-01

    This report describes the modifications implemented into the Goddard Earth Observing System Version-5 (GEOS-5) Atmospheric Data Assimilation System (ADAS) to maintain global conservation of dry atmospheric mass as well as to preserve the model balance of globally integrated precipitation and surface evaporation during reanalysis. Section 1 begins with a review of these global quantities from four current reanalysis efforts. Section 2 introduces the modifications necessary to preserve these constraints within the atmospheric general circulation model (AGCM), the Gridpoint Statistical Interpolation (GSI) analysis procedure, and the Incremental Analysis Update (IAU) algorithm. Section 3 presents experiments quantifying the impact of the new procedure. Section 4 shows preliminary results from its use within the GMAO MERRA-2 Reanalysis project. Section 5 concludes with a summary.

  18. The mass balance of the Greenland ice sheet: sensitivity to climate change as revealed by energy-balance modelling

    NARCIS (Netherlands)

    Oerlemans, J.

    1991-01-01

    The sensitivity of the mass balance of the Greenland ice sheet to climate change is studied with an energy-balance model of the ice/snow surface, applied at 200 m elevation intervals for four characteristic regions of the ice sheet. Solar radiation, longwave radiation, turbulent heat fluxes and refr

  19. Greenland Ice sheet mass balance from satellite and airborne altimetry

    Science.gov (United States)

    Khan, S. A.; Bevis, M. G.; Wahr, J. M.; Wouters, B.; Sasgen, I.; van Dam, T. M.; van den Broeke, M. R.; Hanna, E.; Huybrechts, P.; Kjaer, K.; Korsgaard, N. J.; Bjork, A. A.; Kjeldsen, K. K.

    2013-12-01

    Ice loss from the Greenland Ice Sheet (GrIS) is dominated by loss in the marginal areas. Dynamic induced ice loss and its associated ice surface lowering is often largest close to the glacier calving front and may vary from rates of tens of meters per years to a few meters per year over relatively short distances. Hence, high spatial resolution data are required to accurately estimate volume changes. Here, we estimate ice volume change rate of the Greenland ice sheet using data from Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter during 2003-2009 and CryoSat-2 data during 2010-2012. To improve the volume change estimate we supplement the ICESat and CryoSat data with altimeter surveys from NASA's Airborne Topographic Mapper (ATM) during 2003-2012 and NASA's Land, Vegetation and Ice Sensor (LVIS) during 2007-2012. The Airborne data are mainly concentrated along the ice margin and therefore significantly improve the estimate of the total volume change. Furthermore, we divide the GrIS into six major drainage basins and provide volume loss estimates during 2003-2006, 2006-2009 and 2009-2012 for each basin and separate between melt induced and dynamic ice loss. In order to separate dynamic ice loss from melt processes, we use SMB values from the Regional Atmospheric Climate Model (RACMO2) and SMB values from a positive degree day runoff retention model (Janssens & Huybrechts 2000, Hanna et al. 2011 JGR, updated for this study). Our results show increasing SMB ice loss over the last decade, while dynamic ice loss increased during 2003-2009, but has since been decreasing. Finally, we assess the estimated mass loss using GPS observations from stations located along the edge of the GrIS and measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite gravity mission. Hanna, E., et al. (2011), Greenland Ice Sheet surface mass balance 1870 to 2010 based on Twentieth Century Reanalysis, and links with global climate forcing, J. Geophys. Res

  20. A California Nitrogen Mass Balance: Uncertainties and information needs

    Science.gov (United States)

    Liptzin, D.; Dahlgren, R. A.

    2011-12-01

    The goal of the California Nitrogen (N) Assessment (CNA) is to evaluate the current state of N science, practice, and policy in the state of California. One component is to develop a N mass balance for the state. Because the CNA is an assessment, evaluating the data quality and quantifying uncertainty are also part of the mass balance . We estimate that a total of 1500 Gg of new reactive N is added to California every year. Of this new N, only about half of the N leaves the state while the rest is retained. The main inputs of new reactive N to California are, in order of importance: synthetic N fertilizer, fossil fuel combustion, and biological N fixation. The three largest N outputs from the state are, in order of importance, atmospheric advection, wastewater discharge to the ocean, and riverine discharge to the ocean. Approximately half of the stored N leaches to groundwater, with the other half divided between soils and vegetation, reservoirs, and urban landscapes. These N flows vary not just in magnitude, but also in the uncertainty associated with them. There was no trend in the tonnage of fertilizer sold from 1981-2001, but the 2002-2007 average has remained higher (760 Gg N) than the long-term average (520 Gg N). Bottom up calculations based on crop acreage and fertilization rates are more consistent with the 1980-2001 average suggesting a problem with the sales data. The emission of NOx from fossil fuel burning is one of the most well established flows of N. The production of ammonia and nitrous oxide from fossil fuel combustion is significantly lower than NOx, but there is less evidence to support the emissions inventories. Rates of biological N fixation are speculative with evidence more limited in natural lands than croplands. For most crops it appears that N fixation rates are strongly related to plant production, suggesting that using a single rate across large regions may be inappropriate. In addition, many studies either only measure aboveground N

  1. Mass Balance Re-analysis of Findelengletscher, Switzerland; Benefits of Extensive Snow Accumulation Measurements

    OpenAIRE

    Sold, Leo; Huss, Matthias; Machguth, Horst; Joerg, Philip C.; Leysinger Vieli, Gwendolyn; Linsbauer, Andreas; Salzmann, Nadine; Zemp, Michael; Hoelzle, Martin

    2016-01-01

    A re-analysis is presented here of a 10 year mass balance series at Findelengletscher, a temperate mountain glacier in Switzerland. Calculating glacier-wide mass balance from the set of glaciological point balance observations using conventional approaches, such as the profile or contour method, resulted in significant deviations from the reference value given by the geodetic mass change over a 5 year period. This is attributed to the sparsity of observations at high elevations and to the ina...

  2. Spatial patterns of North Atlantic Oscillation influence on mass balance variability of European glaciers

    OpenAIRE

    Marzeion, B.; A. Nesje

    2012-01-01

    We present and validate a set of minimal models of glacier mass balance variability. The most skillful model is then applied to reconstruct 7735 individual time series of mass balance variability for all glaciers in the European Alps and Scandinavia. Subsequently, we investigate the influence of atmospheric variability associated with the North Atlantic Oscillation (NAO) on the glaciers' mass balances.

    We find a spatial coherence in the glaciers' sensitivity to NA...

  3. The Orographic Climate Factors Contributing to the Mass Balance of Small Glaciers in North-Iceland

    OpenAIRE

    Halkola, Kaisa

    2005-01-01

    This report is a result of a master thesis project. The project was launched to get more information of the factors affecting the mass balance of small glaciers in Northern Iceland. Observations on the glaciers were analysed in comparison with previous estimations of mass balance (Eythorsson and Sigtryggsson, 1971), a degree-day mass-balance model (MBT) and an atmospheric model MM5 (National Centre for Atmospheric Research (NCAR) / Pennsylvania State University).

  4. Daily physical activity as determined by age, body mass and energy balance

    OpenAIRE

    Klaas R Westerterp

    2015-01-01

    Aim Insight into the determinants of physical activity, including age, body mass and energy balance, facilitates the design of intervention studies with body mass and energy balance as determinants of health and optimal performance. Methods An analysis of physical activity energy expenditure in relation to age and body mass and in relation to energy balance, where activity energy expenditure is derived from daily energy expenditure as measured with doubly labelled water and body movement is m...

  5. Re-analysis of seasonal mass balance at Abramov glacier 1968–2014

    OpenAIRE

    Martina Barandun; Matthias Huss; Leo Sold; D. Farinotti; Erlan Azisov; Nadine Salzmann; Ryskul Usubaliev; Alexandr Merkushkin; Martin Hoelzle

    2016-01-01

    Abramov glacier, located in the Pamir Alay, Kyrgyzstan, is a reference glacier within the Global Terrestrial Network for Glaciers. Long-term glaciological measurements exist from 1968 to 1998 and a mass-balance monitoring programme was re-established in 2011. In this study we re-analyse existing mass-balance data and use a spatially distributed mass-balance model to provide continuous seasonal time series of glacier mass balance covering the period 1968–2014. The model is calibrated to season...

  6. Fe and Cu isotope mass balances in the human body

    Science.gov (United States)

    Balter, V.; Albarede, F.; Jaouen, K.

    2011-12-01

    The ranges of the Fe and Cu isotope compositions in the human body are large, i.e. ~3% and ~2%, respectively. Both isotopic fractionations appear to be mainly controlled by redox conditions. The Fe and Cu isotope compositions of the tissues analyzed so far plot on a mixing hyperbolae between a reduced and an oxidized metals pools. The reduced metals pool is composed by erythrocytes, where Fe is bounded to hemoglobin as Fe(II) and Cu to superoxide-dismutase as Cu(I). The oxidized metals pool is composed by hepatocytes, where Fe and Cu are stored as Fe(III) ferritin and as Cu(II) ceruloplasmine, respectively. The position of each biological component in the δ56Fe-δ65Cu diagram therefore reflects the oxidation state of Fe and Cu of the predominant metal carrier protein and allows to quantify Fe and Cu fluxes between organs using mass balance calculations. For instance, serum and clot Fe and Cu isotope compositions show that current biological models of erythropoiesis violates mass conservation requirements, and suggest hidden Fe and Cu pathways during red blood cells synthesis. The results also show that a coupled Fe-Cu strong gender isotopic effect is observed in various organs. The isotopic difference between men and women is unlikely to be due to differential dietary uptake or endometrium loss, but rather reflects the effect of menstrual losses and a correlative solicitation of hepatic stores. We speculate that thorough studies of the metabolism of stable isotopes in normal conditions is a prerequisite for the understanding of the pathological dysregulations.

  7. Radiocarbon mass balance for a Magnox nuclear power station

    International Nuclear Information System (INIS)

    Highlights: • First comprehensive assessment of C-14 arisings in a Magnox nuclear power station. • C-14 production in graphite and coolant gas quantified by activation modelling. • Principal C-14 production pathway is via C-13 with a small contribution from N-14. • C-14 mass balance model provides a basis for analyses on other reactors. - Abstract: Nuclear power generation in the United Kingdom is based principally on graphite-moderated gas-cooled reactors. The mass of irradiated graphite associated with these reactors, including material from associated experimental, prototype and plutonium production reactors, exceeds 96,000 tonnes. One of the principal long-lived radionuclides produced during graphite irradiation is radiocarbon (C-14). Its potential as a hazard must be taken into account in decommissioning and graphite waste management strategies. While C-14 production processes are well-understood, radionuclide distributions and concentrations need to be characterised. A common misconception is that generic statements can be made about C-14 precursors and their location. In fact, the composition of the original manufactured material, the chemical environment of the graphite during service and its irradiation history will all influence C-14 levels. The analysis presented here provides the first assessment of the principal C-14 activation pathways for a UK Magnox reactor. Activation modelling has been used to predict C-14 production rates in both the graphite core and the carbon dioxide coolant over a selected period of operation and the results compared with monitored site C-14 discharges. Principal activation routes have been identified, which should inform future graphite waste management strategies relating to radiocarbon

  8. Stable isotope mass balance of lakes: a contemporary perspective

    Science.gov (United States)

    Gibson, J. J.; Birks, S. J.; Yi, Y.

    2016-01-01

    The theoretical basis for application of stable isotope mass balance of lakes is described for a range of climatic situations including low latitude, high latitude, high altitude, continental and coastal systems, as well as cases where the atmospheric boundary layer is significantly modified by the lake evaporation process. The effects of seasonality on isotopic offset between precipitation and atmospheric vapour and the slope of the local evaporation line are described. Atmospheric feedback and its role in labelling the isotopic composition of the Laurentian Great Lakes and tropical lakes is discussed. Several important considerations are suggested to improve parameterization of quantitative paleoclimatic reconstructions including use of assumptions that are appropriate for the climatic setting, for the atmospheric feedback situation, for salinity, and headwater setting. Potential for use of dual-isotopes to trace past changes in seasonality and input, and a dual-lake index method that can potentially be used to trace connectivity of lakes are presented. In cases where modern or paleo-evaporation systems may be under-defined there are inherent limitations in the degree of quantification that can be attained.

  9. Mass balance of reaction products from irradiated TCE vapor

    International Nuclear Information System (INIS)

    Trichloroethylene (TCE) vapor, at a concentration of 3,000 ppmv in synthetic air, was sealed in Tedlar bags and irradiated with a 3.7 MeV electron beam. Bags of dry vapor and vapor at 90% relative humidity were irradiated. Doses up to 11 megarads (11 MR) were applied. Each bag was chemically analyzed for reaction products and a mass balance of the chlorine and carbon was obtained within the 11 MR dose range. The results of these radiolysis experiments and chemical analysis show that, given the proper treatment, the TCE concentration is reduced to below detection limit and the reaction products of the organic carbon and chlorine are carbon monoxide (CO), carbon dioxide (CO2), chlorine gas (Cl2) and hydrochloric acid (HCl). No detectable amounts of dichloroacetyl chloride (DCAC) or phosgene (PG) remained in the sample after proper treatment. DCAC and PG were found only as intermediary oxidation products of the TCE. High energy ionizing radiation, as electron beams and bremsstrahlung, is a new treatment technology for destroying toxic compounds and hazardous wastes. A demonstration of complete destruction of organic products, using this treatment at standard temperature and pressure, is expected to help implement the use of this technology

  10. Glacier crevasses: Observations, models, and mass balance implications

    Science.gov (United States)

    Colgan, William; Rajaram, Harihar; Abdalati, Waleed; McCutchan, Cheryl; Mottram, Ruth; Moussavi, Mahsa S.; Grigsby, Shane

    2016-03-01

    We review the findings of approximately 60 years of in situ and remote sensing studies of glacier crevasses, as well as the three broad classes of numerical models now employed to simulate crevasse fracture. The relatively new insight that mixed-mode fracture in local stress equilibrium, rather than downstream advection alone, can introduce nontrivial curvature to crevasse geometry may merit the reinterpretation of some key historical observation studies. In the past three decades, there have been tremendous advances in the spatial resolution of satellite imagery, as well as fully automated algorithms capable of tracking crevasse displacements between repeat images. Despite considerable advances in developing fully transient three-dimensional ice flow models over the past two decades, both the zero stress and linear elastic fracture mechanics crevasse models have remained fundamentally unchanged over this time. In the past decade, however, multidimensional and transient formulations of the continuum damage mechanics approach to simulating ice fracture have emerged. The combination of employing damage mechanics to represent slow upstream deterioration of ice strength and fracture mechanics to represent rapid failure at downstream termini holds promise for implementation in large-scale ice sheet models. Finally, given the broad interest in the sea level rise implications of recent and future cryospheric change, we provide a synthesis of 10 mechanisms by which crevasses can influence glacier mass balance.

  11. Role of isospin degree of freedom on the mass dependence of balance energy

    OpenAIRE

    Gautam, Sakshi; Sood, Aman D.

    2010-01-01

    The effect of isospin degree of freedom on balance energy and its mass dependence has been studied for the mass range between 50 and 350. Our results shows the dominance of Coulomb potential in isospin effects.

  12. The mass balance of the Greenland ice sheet: sensitivity to climate change as revealed by energy-balance modelling

    OpenAIRE

    Oerlemans, J.

    1991-01-01

    The sensitivity of the mass balance of the Greenland ice sheet to climate change is studied with an energy-balance model of the ice/snow surface, applied at 200 m elevation intervals for four characteristic regions of the ice sheet. Solar radiation, longwave radiation, turbulent heat fluxes and refreezing of melt water in the snow pack are treated separately. The daily cycle is fully resolved. For the climatology chosen as input (mainly from work by A. Ohmura), the, mean specific balance prod...

  13. Mass balance, meteorological, and runoff measurements at South Cascade Glacier, Washington, 1992 balance year

    Science.gov (United States)

    Krimmel, R.M.

    1993-01-01

    Values of winter snow accumulation and summer snow, firn, and ice ablation were measured at South Cascade Glacier, WA, to determine the winter and net balance for the 1992 balance year. The 1992 winter balance, averaged over the glacier, was 1.91 m, and the net balance was -2.01 m. This extremely negative balance continued a trend of negative balance years beginning in 1977. Air temperature (at 1,615 m and 1,867 m), barometric pressure, precipitation, and runoff from this glacier basin and an adjacent non-glacierized basin were also continuously measured. This report makes all these data, in tabular, graphical, and machine-readable forms, available to users.

  14. Mass balance of Glaciar Zongo, Bolivia, between 1956 and 2006, using glaciological, hydrological and geodetic methods

    OpenAIRE

    Soruco, Alvaro; Vincent, C; Francou, Bernard; P. Ribstein; Berger, Thomas; Sicart, Jean-Emmanuel; Wagnon, Patrick; Arnaud, Yves; Favier, V.; Lejeune, Y.

    2009-01-01

    The longest continuous glaciological mass-balance time-series in the intertropical zone of South America goes back to 1991 on Glaciar Zongo, Bolivia. Photogrammetric and hydrological data have been used to (1) check the specific net balance over long periods and (2) extend the mass-balance time series over the last 50 years. These data reveal a bias in the glaciological mass balance which can be explained by the field-measurement sampling network. Our study shows a large temporal variability ...

  15. Climate - glacier links on Bogerbreen, Svalbard : Glacier mass balance investigations in central Spitsbergen 2004 / 2005

    OpenAIRE

    2006-01-01

    Abstract Glaciers are key indicators for climate change. Mass balance studies form the important link between advances and retreats of glaciers to changes in climate. Mass balance studies were performed in the balance year 2004/05 on Bogerbreen as part of my Master thesis. Bogerbreen is a valley glacier with a size of 3.3 km² located in central Spitsbergen, Svalbard at 78 degrees north and 15 degrees east. The direct glaciological method was applied to measure winter mass balance using sno...

  16. Mass-balance ecosystem model of the East China Sea

    Institute of Scientific and Technical Information of China (English)

    Jiahua Cheng; William W.L. Cheung; Tony J. Pitcher

    2009-01-01

    Using the Ecopath mass-balance trophodynamic model, this paper analyzed the trophic levels, flows, food web structure and ecosys-tem maturity of the East China Sea, and identified ecologically important functional groups in the ecosystem. The model is based on fishery resource surveys of the East China Sea in 2000, studies on diet composition and global databases such as FishBase and the Sea Around Us Project Database. The results showed that trophic levels of the functional groups are between 2.86 and 4.37, with an average of 3.32. Anchocy (Engraulis japonicus), small fishes and benthic crustaceans such as shrimps and crabs are important groups in terms of the trophic structure and flow dynamics in the East China Sea. Energy flows of most groups are between specific trophic levels, except file fish (Thamnaconus spp.), pomfret (Pampus spp.) and cephalopods. Trophic transfer efficiency of levels Ⅱ,Ⅲ,Ⅳ and more than Ⅴ are 11.8%, 21.1%, 17.4% and 22.1-22.5%, respectively. Effects of fishery-the largest 'consumer' of the ecosystem -are much stronger than those exerted by biological groups in the system. The model suggests that the current fishery can further reduce the complexity of the ecosystem. Evaluations of the system indices suggest that maturity of the ecosystem is low. The conclusion of this model indicates that it was the overfishing that caused the ecosystem of the East China Sea declined, which should be taken into account as a critical reference for fisheries management in the future.

  17. Mass balance investigation of alpine glaciers through LANDSAT TM data

    Science.gov (United States)

    Bayr, Klaus J.

    1989-01-01

    An analysis of LANDSAT Thematic Mapper (TM) data of the Pasterze Glacier and the Kleines Fleisskees in the Austrian Alps was undertaken and compared with meteorological data of nearby weather stations. Alpine or valley glaciers can be used to study regional and worldwide climate changes. Alpine glaciers respond relatively fast to a warming or cooling trend in temperature through an advance or a retreat of the terminus. In addition, the mass balance of the glacier is being affected. Last year two TM scenes of the Pasterze Glacier of Aug. 1984 and Aug. 1986 were used to study the difference in reflectance. This year, in addition to the scenes from last year, one MSS scene of Aug. 1976 and a TM scene from 1988 were examined for both the Pasterze Glacier and the Kleines Fleisskees. During the overpass of the LANDSAT on 6 Aug. 1988 ground truthing on the Pasterze Glacier was undertaken. The results indicate that there was considerable more reflectance in 1976 and 1984 than in 1986 and 1988. The climatological data of the weather stations Sonnblick and Rudolfshuette were examined and compared with the results found through the LANDSAT data. There were relations between the meteorological and LANDSAT data: the average temperature over the last 100 years showed an increase of .4 C, the snowfall was declining during the same time period but the overall precipitation did not reveal any significant change over the same period. With the use of an interactive image analysis computer, the LANDSAT scenes were studied. The terminus of the Pasterze Glacier retreated 348 m and the terminus of the Kleines Fleisskees 121 m since 1965. This approach using LANDSAT MSS and TM digital data in conjunction with meteorological data can be effectively used to monitor regional and worldwide climate changes.

  18. Can we close the long term mass balance equation for pollutants in highway ponds?

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael R.

    2007-01-01

    The paper discusses the prospects of finding the long term mass balance on basis of short term simulations. A step in this process is to see to which degree the mass balance equation can be closed by measurements. Accordingly the total accumulation of heavy metals and PAH's in 8 Danish detention ...

  19. Midlatitude Forcing Mechanisms for Glacier Mass Balance Investigated Using General Circulation Models

    NARCIS (Netherlands)

    Reichert, B.K.; Bengtsson, L.; Oerlemans, J.

    2001-01-01

    A process-oriented modeling approach is applied in order to simulate glacier mass balance for individual glaciers using statistically downscaled general circulation models (GCMs). Glacier-specific seasonal sensitivity characteristics based on a mass balance model of intermediate complexity are used

  20. Mass balance, energy and exergy analysis of bio-oil production by fast pyrolysis

    Science.gov (United States)

    Mass, energy and exergy balances are analyzed for bio-oil production in a bench scale fast pyrolysis system developed by the USDA’s Agricultural Research Service (ARS) for the processing of commodity crops to fuel intermediates. Because mass balance closure is difficult to achieve due, in part, to ...

  1. Spatial patterns of North Atlantic Oscillation influence on mass balance variability of European glaciers

    Directory of Open Access Journals (Sweden)

    B. Marzeion

    2012-06-01

    Full Text Available We present and validate a set of minimal models of glacier mass balance variability. The most skillful model is then applied to reconstruct 7735 individual time series of mass balance variability for all glaciers in the European Alps and Scandinavia. Subsequently, we investigate the influence of atmospheric variability associated with the North Atlantic Oscillation (NAO on the glaciers' mass balances.

    We find a spatial coherence in the glaciers' sensitivity to NAO forcing which is caused by regionally similar mechanisms relating the NAO forcing to the mass balance: in southwestern Scandinavia, winter precipitation causes a correlation of mass balances with the NAO. In northern Scandinavia, temperature anomalies outside the core winter season cause an anti-correlation between NAO and mass balances. In the western Alps, both temperature and winter precipitation anomalies lead to a weak anti-correlation of mass balances with the NAO, while in the eastern Alps, the influences of winter precipitation and temperature anomalies tend to cancel each other, and only on the southern side a slight anti-correlation of mass balances with the NAO prevails.

  2. Greenland surface mass-balance observations from the ice-sheet ablation area and local glaciers

    DEFF Research Database (Denmark)

    Machguth, Horst; Thomsen, Henrik; Weidick, Anker;

    2016-01-01

    Glacier surface mass-balance measurements on Greenland started more than a century ago, but no compilation exists of the observations from the ablation area of the ice sheet and local glaciers. Such data could be used in the evaluation of modelled surface mass balance, or to document changes in g...

  3. Net mass balance calculations for the Shirase Drainage Basin, east Antarctica, using the mass budget method

    Science.gov (United States)

    Nakamura, Kazuki; Yamanokuchi, Tsutomu; Doi, Koichiro; Shibuya, Kazuo

    2016-06-01

    We quantify the mass budget of the Shirase drainage basin (SHI), Antarctica, by separately estimating snow accumulation (surface mass balance; SMB) and glacier ice mass discharge (IMD). We estimated the SMB in the SHI, using a regional atmospheric climate model (RACMO2.1). The SMB of the mainstream A flow region was 12.1 ± 1.5 Gt a-1 for an area of 1.985 × 105 km2. Obvious overestimation of the model round the coast, ∼0.5 Gt a-1, was corrected for. For calculating the IMD, we employed a 15-m resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with a digital elevation model (DEM) to determine the heights at the grounding line (GL), after comparison with the interpolated Bamber DEM grid heights; the results of this are referred to as the measured heights. Ice thickness data at the GL were inferred by using a free-board relationship between the measured height and the ice thickness, and considering the measured firn depth correction (4.2 m with the reference ice density of 910 kg m-3) for the nearby blue-ice area. The total IMD was estimated to be 14.0 ± 1.8 Gt a-1. Semi-empirical firn densification model gives the estimate within 0.1-0.2 Gt a-1 difference. The estimated net mass balance, -1.9 Gt a-1, has a two-σ uncertainty of ±3.3 Gt a-1, and probable melt water discharge strongly suggests negative NMB, although the associated uncertainty is large.

  4. Hybrid inventory, gravimetry and altimetry (HIGA mass balance product for Greenland and the Canadian Arctic

    Directory of Open Access Journals (Sweden)

    W. Colgan

    2014-01-01

    Full Text Available We present a novel inversion algorithm that generates a mass balance field that is simultaneously consistent with independent observations of glacier inventory derived from optical imagery, cryosphere-attributed mass changes derived from satellite gravimetry, and ice surface elevation changes derived from airborne and satellite altimetry. We use this algorithm to assess mass balance across Greenland and the Canadian Arctic over the December 2003 to December 2010 period at 26 km resolution. We assess a total mass loss of 316 ± 37 Gt a−1 over Greenland and the Canadian Arctic, with 217 ± 20 Gt a−1 being attributed to the Greenland Ice Sheet proper, and 38 ± 6 Gt a−1 and 50 ± 8 Gt a−1 being attributed to peripheral glaciers in Greenland and the Canadian Arctic, respectively. These absolute values are dependent on the gravimetry-derived spherical harmonic representation we invert. Our attempt to validate local values of algorithm-inferred mass balance reveals a paucity of in situ observations. At four sites, where direct comparison between algorithm-inferred and in situ mass balance is valid, we find an RMSD of 0.18 m WE a−1. Differencing algorithm-inferred mass balance with previously modelled surface mass balance, in order to solve the ice dynamic portion of mass balance as a residual, allows the transient glacier continuity equation to be spatially partitioned across Greenland.

  5. Extrapolating glacier mass balance to the mountain-range scale: the European Alps 1900–2100

    OpenAIRE

    Huss, M.

    2012-01-01

    This study addresses the extrapolation of in-situ glacier mass balance measurements to the mountain-range scale and aims at deriving time series of area-averaged mass balance and ice volume change for all glaciers in the European Alps for the period 1900–2100. Long-term mass balance series for 50 Swiss glaciers based on a combination of field data and modelling, and WGMS data for glaciers in Austria, France and Italy are used. A complete glacier inventory is available for the year 2003. Mass ...

  6. Mass Balance of a Maritime Glacier on the Southeast Tibetan Plateau and Its Climatic Sensitivity

    Science.gov (United States)

    Yang, W.

    2014-12-01

    Based on glacio-meteorological measurements and mass-balance stake records during the five-year period of 2005-2010 on the southeast Tibetan Plateau, an energy-mass balance model was applied to study the surface mass balance of the Parlung No. 94 Glacier, as well as its response to regional climate conditions. The primary physical parameters involved in the model were locally calibrated by using relevant glacio-meteorological datasets. The good agreement between the snowpack height/mass balance simulations and the in-situ measurements available from a total of 12 monitoring stakes over this glacier confirmed the satisfactory performance of the energy-mass balance model. Results suggested that the recent state of the Parlung No. 94 Glacier was far removed from the 'ideal' climatic regime leading to zero mass balance, with its annual mass balance of approximately -0.9 m w.e. during 2005-2010. Climatic sensitivity experiments were also carried out to interpret the observed mass-balance changes, and the experiments demonstrated that the maritime glaciers concerned herein were theoretically more vulnerable to ongoing climate warming on the Tibetan Plateau than potential changes in the amount of precipitation. A plausible causal explanation for the recent glacier shrinkage in this region was concerned with the increasing air temperature. Moreover, both the mass balance simulations and the field measurements indicated that the mass accumulation over this maritime glacier occurred primarily in the boreal spring. Such "spring-accumulation type" glaciers are presumed to be distributed mainly within a narrow wedge-shaped region along the Brahmaputra River. Climatic sensitivities of the glacier mass balanceare also found to be closely linked to the regional precipitation seasonality that is simultaneously modulated by various atmospheric circulation patterns, such as the southern westerlies, the Bay of Bengal vortex in the spring season and the Indian monsoon in the summer

  7. Glacier modeling in support of field observations of mass balance at South Cascade Glacier, Washington, USA

    Science.gov (United States)

    Josberger, Edward G.; Bidlake, William R.

    2010-01-01

    The long-term USGS measurement and reporting of mass balance at South Cascade Glacier was assisted in balance years 2006 and 2007 by a new mass balance model. The model incorporates a temperature-index melt computation and accumulation is modeled from glacier air temperature and gaged precipitation at a remote site. Mass balance modeling was used with glaciological measurements to estimate dates and magnitudes of critical mass balance phenomena. In support of the modeling, a detailed analysis was made of the "glacier cooling effect" that reduces summer air temperature near the ice surface as compared to that predicted on the basis of a spatially uniform temperature lapse rate. The analysis was based on several years of data from measurements of near-surface air temperature on the glacier. The 2006 and 2007 winter balances of South Cascade Glacier, computed with this new, model-augmented methodology, were 2.61 and 3.41 mWE, respectively. The 2006 and 2007 summer balances were -4.20 and -3.63 mWE, respectively, and the 2006 and 2007 net balances were -1.59 and -0.22 mWE. PDF version of a presentation on the mass balance of South Cascade Glacier in Washington state. Presented at the American Geophysical Union Fall Meeting 2010.

  8. Hybrid inventory, gravimetry and altimetry (HIGA) mass balance product for Greenland and the Canadian Arctic

    OpenAIRE

    Colgan, W.; W. Abdalati; Citterio, M.; Csatho, B.; X. Fettweis; Luthcke, S.; G. Moholdt; M. Stober

    2014-01-01

    We present a novel inversion algorithm that generates a mass balance field that is simultaneously consistent with independent observations of glacier inventory derived from optical imagery, cryosphere-attributed mass changes derived from satellite gravimetry, and ice surface elevation changes derived from airborne and satellite altimetry. We use this algorithm to assess mass balance across Greenland and the Canadian Arctic over the December 2003 to December ...

  9. Impact parameter dependence of isospin effects on the mass dependence of balance energy

    OpenAIRE

    Gautam, Sakshi; Sood, Aman D.

    2010-01-01

    We study the effect of isospin degree of freedom on the balance energy as well as its mass dependence throughout the mass range 48-270 for two sets of isobaric systems with N/Z = 1 and 1.4 using isospin-dependent quantum molecular dynamics (IQMD) model. Our fndings reveal the dominance of Coulomb repulsion in isospin effects on balance energy as well as its mass dependence throughout the range of the colliding geometry.

  10. Mass balance of the Greenland ice sheet (2003-2008) from ICESat data

    DEFF Research Database (Denmark)

    Sørensen, Louise Sandberg; Simonsen, Sebastian Bjerregaard; Nielsen, Karina;

    2011-01-01

    ICESat has provided surface elevation measurements of the ice sheets since the launch in January 2003, resulting in a unique dataset for monitoring the changes of the cryosphere. Here, we present a novel method for determining the mass balance of the Greenland ice sheet, derived from ICESat...... studies of the Greenland ice sheet mass balance, based on different remote-sensing techniques....... altimetry data. Three different methods for deriving elevation changes from the ICESat altimetry dataset are used. This multi-method approach provides a method to assess the complexity of deriving elevation changes from this dataset. The altimetry alone can not provide an estimate of the mass balance...

  11. Paradox applications integration ATP's for MAC and mass balance programs

    International Nuclear Information System (INIS)

    The K Basins Materials Accounting (MAC) and Material Balance (MBA) database system were set up to run under one common applications program. This Acceptance Test Plan (ATP) describes how the code was to be tested to verify its correctness. The scope of the tests is minimal, since both MAC and MBA have already been tested in detail as stand-alone programs

  12. Calibration of a surface mass balance model for global-scale applications

    Directory of Open Access Journals (Sweden)

    R. H. Giesen

    2012-12-01

    Full Text Available Global applications of surface mass balance models have large uncertainties, as a result of poor climate input data and limited availability of mass balance measurements. This study addresses several possible consequences of these limitations for the modelled mass balance. This is done by applying a simple surface mass balance model that only requires air temperature and precipitation as input data, to glaciers in different regions. In contrast to other models used in global applications, this model separately calculates the contributions of net solar radiation and the temperature-dependent fluxes to the energy balance. We derive a relation for these temperature-dependent fluxes using automatic weather station (AWS measurements from glaciers in different climates. With local, hourly input data, the model is well able to simulate the observed seasonal variations in the surface energy and mass balance at the AWS sites. Replacing the hourly local data by monthly gridded climate data removes summer snowfall and winter melt events and, hence, influences the modelled mass balance most on locations with a small seasonal temperature cycle. Modelled winter mass balance profiles are fitted to observations on 82 glaciers in different regions to determine representative values for the multiplication factor and vertical gradient of precipitation. For 75 of the 82 glaciers, the precipitation provided by the climate dataset has to be multiplied with a factor above unity; the median factor is 2.5. The vertical precipitation gradient ranges from negative to positive values, with more positive values for maritime glaciers and a median value of 1.5 mm a−1 m−1. With calibrated precipitation, the modelled annual mass balance gradient closely resembles the observations on the 82 glaciers, the absolute values are matched by adjusting either the incoming solar radiation, the temperature-dependent flux or the air temperature. The mass balance

  13. Global application of a surface mass balance model using gridded climate data

    Directory of Open Access Journals (Sweden)

    R. H. Giesen

    2012-04-01

    Full Text Available Global applications of surface mass balance models have large uncertainties, as a result of poor climate input data and limited availability of mass balance measurements. This study addresses several possible consequences of these limitations for the modelled mass balance. This is done by applying a simple surface mass balance model that only requires air temperature and precipitation as input data, to glaciers in different regions. In contrast to other models used in global applications, this model separately calculates the contributions of net solar radiation and the temperature-dependent fluxes to the energy balance. We derive a relation for these temperature-dependent fluxes using automatic weather station (AWS measurements from glaciers in different climates. With local, hourly input data, the model is well able to simulate the observed seasonal variations in the surface energy and mass balance at the AWS sites. Replacing the hourly local data by monthly gridded climate data removes summer snowfall and winter melt events and hence influences the modelled mass balance most on locations with a small seasonal temperature cycle. Representative values for the multiplication factor and vertical gradient of precipitation are determined by fitting modelled winter mass balance profiles to observations on 80 glaciers in different regions. For 72 of the 80 glaciers, the precipitation provided by the climate data set has to be multiplied with a factor above unity; the median factor is 2.55. The vertical precipitation gradient ranges from negative to positive values, with more positive values for maritime glaciers and a median value of 1.5 mm a−1 m. With calibrated precipitation, the modelled annual mass balance gradient closely resembles the observations on the 80 glaciers, the absolute values are matched by adjusting either the incoming solar radiation, the temperature-dependent flux or the air temperature. The mass balance sensitivity to

  14. Calibration of a surface mass balance model for global-scale applications

    Science.gov (United States)

    Giesen, R. H.; Oerlemans, J.

    2012-12-01

    Global applications of surface mass balance models have large uncertainties, as a result of poor climate input data and limited availability of mass balance measurements. This study addresses several possible consequences of these limitations for the modelled mass balance. This is done by applying a simple surface mass balance model that only requires air temperature and precipitation as input data, to glaciers in different regions. In contrast to other models used in global applications, this model separately calculates the contributions of net solar radiation and the temperature-dependent fluxes to the energy balance. We derive a relation for these temperature-dependent fluxes using automatic weather station (AWS) measurements from glaciers in different climates. With local, hourly input data, the model is well able to simulate the observed seasonal variations in the surface energy and mass balance at the AWS sites. Replacing the hourly local data by monthly gridded climate data removes summer snowfall and winter melt events and, hence, influences the modelled mass balance most on locations with a small seasonal temperature cycle. Modelled winter mass balance profiles are fitted to observations on 82 glaciers in different regions to determine representative values for the multiplication factor and vertical gradient of precipitation. For 75 of the 82 glaciers, the precipitation provided by the climate dataset has to be multiplied with a factor above unity; the median factor is 2.5. The vertical precipitation gradient ranges from negative to positive values, with more positive values for maritime glaciers and a median value of 1.5 mm a-1 m-1. With calibrated precipitation, the modelled annual mass balance gradient closely resembles the observations on the 82 glaciers, the absolute values are matched by adjusting either the incoming solar radiation, the temperature-dependent flux or the air temperature. The mass balance sensitivity to changes in temperature is

  15. Global application of a surface mass balance model using gridded climate data

    Science.gov (United States)

    Giesen, R. H.; Oerlemans, J.

    2012-04-01

    Global applications of surface mass balance models have large uncertainties, as a result of poor climate input data and limited availability of mass balance measurements. This study addresses several possible consequences of these limitations for the modelled mass balance. This is done by applying a simple surface mass balance model that only requires air temperature and precipitation as input data, to glaciers in different regions. In contrast to other models used in global applications, this model separately calculates the contributions of net solar radiation and the temperature-dependent fluxes to the energy balance. We derive a relation for these temperature-dependent fluxes using automatic weather station (AWS) measurements from glaciers in different climates. With local, hourly input data, the model is well able to simulate the observed seasonal variations in the surface energy and mass balance at the AWS sites. Replacing the hourly local data by monthly gridded climate data removes summer snowfall and winter melt events and hence influences the modelled mass balance most on locations with a small seasonal temperature cycle. Representative values for the multiplication factor and vertical gradient of precipitation are determined by fitting modelled winter mass balance profiles to observations on 80 glaciers in different regions. For 72 of the 80 glaciers, the precipitation provided by the climate data set has to be multiplied with a factor above unity; the median factor is 2.55. The vertical precipitation gradient ranges from negative to positive values, with more positive values for maritime glaciers and a median value of 1.5 mm a-1 m. With calibrated precipitation, the modelled annual mass balance gradient closely resembles the observations on the 80 glaciers, the absolute values are matched by adjusting either the incoming solar radiation, the temperature-dependent flux or the air temperature. The mass balance sensitivity to changes in temperature is

  16. Reconstructing the mass balance of Brewster Glacier, New Zealand, using MODIS-derived glacier-wide albedo

    OpenAIRE

    Sirguey, Pascal; Still, Holly; Cullen, Nicolas J.; Dumont, Marie; Arnaud, Yves; Conway, Jonathan P.

    2016-01-01

    In New Zealand, direct measurements of mass balance are sparse due to the inaccessibility of glaciers in the Southern Alps and the logistical difficulties associated with maintaining a mass balance record. In order to explore the benefit of remotely sensed imaging to monitor mass balance in the Southern Alps, this research assesses the relationship between measurements of glacier surface albedo derived from MODerate resolution Imaging Spectroradiometer (MODIS) and mass balance observations us...

  17. Spent Nuclear Fuel (SNF) Project Multi Canister Overpack (MCO) Process Flow Diagram Mass Balance Calculations

    Energy Technology Data Exchange (ETDEWEB)

    KLEM, M.J.

    2000-09-08

    The purpose of this calculation document is to develop the bases for the material balances of the Multi-Canister Overpack (MCO) Level 1 Process Flow Diagram (PFD). The attached mass balances support revision two of the PFD for the MCO and provide future reference.

  18. Mass balance model for Hammerfest LNG plant Snøhvit

    OpenAIRE

    Lauvdal, Anders

    2007-01-01

    The goal of the task is to develop and test a mass balance model for the entire Snøhvit facility which makes it possible to balance all streams inn and out. The model is implemented in an excel sheet. Also production rate calculations for LNG, LPG and condensate are made based on updated well and field data.

  19. Exploring uncertainty in glacier mass balance modelling with Monte Carlo simulation

    NARCIS (Netherlands)

    Machguth, H.; Purves, R.S.; Oerlemans, J.; Hoelzle, M.; Paul, F.

    2008-01-01

    By means of Monte Carlo simulations we calculated uncertainty in modelled cumulative mass balance over 400 days at one particular point on the tongue of Morteratsch Glacier, Switzerland, using a glacier energy balance model of intermediate complexity. Before uncertainty assessment, the model was tun

  20. Production of resonances in a thermal model: invariant-mass spectra and balance functions

    OpenAIRE

    Florkowski, W.; Broniowski, W.; Bozek, P.

    2004-01-01

    We present a calculation of the pi+ pi- invariant-mass correlations and the pion balance functions in the single-freeze-out model. A satisfactory agreement with the data for Au+Au collisions is found.

  1. USGS Alaska Benchmark Glacier Mass Balance Data - Phase 1; Gulkana and Wolverine Glaciers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Since the late 1950s, USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Similar measurements began at Sperry Glacier,...

  2. BALANCE

    Science.gov (United States)

    Carmichael, H.

    1953-01-01

    A torsional-type analytical balance designed to arrive at its equilibrium point more quickly than previous balances is described. In order to prevent external heat sources creating air currents inside the balance casing that would reiard the attainment of equilibrium conditions, a relatively thick casing shaped as an inverted U is placed over the load support arms and the balance beam. This casing is of a metal of good thernnal conductivity characteristics, such as copper or aluminum, in order that heat applied to one portion of the balance is quickly conducted to all other sensitive areas, thus effectively preventing the fornnation of air currents caused by unequal heating of the balance.

  3. Quantifying the Mass Balance of Ice Caps on Severnaya Zemlya, Russian High Arctic. I: Climate and Mass Balance of the Vavilov Ice Cap

    NARCIS (Netherlands)

    Bassford, R.P.; Siegert, M.J.; Dowdeswell, J.A.; Oerlemans, J.; Glazovsky, A.F.; Macheret, Y.Y.

    2006-01-01

    Due to their remote location within the Russian High Arctic, little is known about the mass balance of ice caps on Severnaya Zemlya now and in the past. Such information is critical, however, to building a global picture of the cryospheric response to climate change. This paper provides a numerical

  4. Basin-scale partitioning of Greenland ice sheet mass balance components (2007-2011)

    DEFF Research Database (Denmark)

    Andersen, M.L.; Stenseng, Lars; Skourup, Henriette;

    2015-01-01

    of the gate. Using a 1961-1990 reference climatology SMB field from the MAR regional climate model, we quantify ice sheet mass balance within eighteen basins. We find a 2007-2011 mean D of 515±57 Gtyr-1. We find a 2007-2011 mean total mass balance of -262±21 Gtyr-1, which is equal to a 0.73 mm yr-1 global sea...

  5. Comparison of direct and geodetic mass balances on a multi-annual time scale

    Directory of Open Access Journals (Sweden)

    A. Fischer

    2011-02-01

    Full Text Available The geodetic mass balances of six Austrian glaciers over 19 periods between 1953 and 2006 are compared to the direct mass balances over the same periods. For two glaciers, Hintereisferner and Kesselwandferner, case studies showing possible reasons for discrepancies between the geodetic and the direct mass balance are presented. The mean annual geodetic mass balance for all periods is −0.5 m w.e. a−1, the mean annual direct mass balance −0.4 m w.e. a−1. The mean cumulative difference is −0.6 m w.e., the minimum −7.3 m w.e., and the maximum 5.6 m w.e. The accuracy of geodetic mass balance may depend on the accuracy of the DEMs, which ranges from 2 m w.e. for photogrammetric data to 0.02 m w.e. for airborne laser scanning (LiDAR data. Basal melt, seasonal snow cover, and density changes of the surface layer also contribute up to 0.7 m w.e. to the difference between the two methods over the investigated period of 10 yr. On Hintereisferner, the fraction of area covered by snow or firn has been changing within 1953–2006. The accumulation area is not identical with the firn area, and both are not coincident with areas of volume gain. Longer periods between the acquisition of the DEMs do not necessarily result in a higher accuracy of the geodetic mass balance. Trends in the difference between the direct and the geodetic data vary from glacier to glacier and can differ systematically for specific glaciers under specific types of climate forcing. Ultimately, geodetic and direct mass balance data are complementary, and great care must be taken when attempting to combine them.

  6. A synthesis of the Antarctic surface mass balance during the last 800 yr

    OpenAIRE

    Frezzotti, M.; C. Scarchilli; Becagli, S.; Proposito, M.; S. Urbini

    2013-01-01

    Global climate models suggest that Antarctic snowfall should increase in a warming climate and mitigate rises in the sea level. Several processes affect surface mass balance (SMB), introducing large uncertainties in past, present and future ice sheet mass balance. To provide an extended perspective on the past SMB of Antarctica, we used 67 firn/ice core records to reconstruct the temporal variability in the SMB over the past 800 yr and, in greater detail, over the last 200 yr.

  7. A synthesis of the antarctic surface mass balance during the last eight centuries

    OpenAIRE

    Frezzotti, M.; C. Scarchilli; Becagli, S.; Proposito, M.; S. Urbini

    2012-01-01

    Global climate models suggest that Antarctic snowfall should increase in a warming climate and mitigate sea level rise, mainly due to the greater moisture-holding capacity of the warmer atmosphere. Several processes act on snow accumulation or surface mass balance (SMB), introducing large uncertainties in the past, present, and future ice sheet mass balance. To provide an extended past perspective of the SMB of Antarctica, we used 66 firn/ice core records to reconstruct the temporal vari...

  8. Interannual to decadal time-scale variations in glacier mass balance [abstract

    OpenAIRE

    Walters, Roy A.

    1996-01-01

    EXTRACT (SEE PDF FOR FULL ABSTRACT): The mass balance of glaciers depends on the seasonal variation in precipitation, temperature, and insolation. For glaciers in western North America, these meteorological variables are influenced by the large-scale atmospheric circulation over the northern Pacific Ocean. The purpose of this study is to gain a better understanding of the relationship between mass balance at glaciers in western North America and the large-scale atmospheric effects at inte...

  9. Higher surface mass balance of the Greenland ice sheet revealed by high-resolution climate modeling

    OpenAIRE

    Ettema, J.; M. R. van den Broeke; van Meijgaard, E.; Van De Berg, W. J.; Bamber, Jonathan L.; Box, J. E.; Bales, R. C.

    2009-01-01

    High-resolution (∼11 km) regional climate modeling shows total annual precipitation on the Greenland ice sheet for 1958-2007 to be up to 24% and surface mass balance up to 63% higher than previously thought. The largest differences occur in coastal southeast Greenland, where the much higher resolution facilitates capturing snow accumulation peaks that past five-fold coarser resolution regional climate models missed. The surface mass balance trend over the full 1958-2007 period reveals the cla...

  10. Mass-balance reconstruction for Glacier No. 354, Tien Shan, from 2003 to 2014

    OpenAIRE

    2016-01-01

    This study presents a reconstruction of the seasonal mass balance of Glacier No. 354, located in the Akshiirak range, Kyrgyzstan, from 2003 to 2014. We use a distributed accumulation and temperature-index melt model driven by daily air temperature and precipitation from a nearby meteorological station. The model is calibrated with in situ measurements of the annual mass balance collected from 2011 to 2014. The snow-cover depletion pattern observed using satellite imagery provides additional i...

  11. The influence of changes in glacier extent and surface elevation on modeled mass balance

    OpenAIRE

    Paul, F.

    2010-01-01

    Glaciers are widely recognized as unique demonstration objects for climate change impacts, mostly due to the strong change of glacier length in response to small climatic changes. However, glacier mass balance as the direct response to the annual atmospheric conditions can be better interpreted in meteorological terms. When the climatic signal is deduced from long-term mass balance data, changes in glacier geometry (i.e. surface extent and elevation) must be considered as such adjustments ...

  12. Re-analysing eleven years of mass balance observations at Langenferner, Ortler-Cevedale Group, Italy

    Science.gov (United States)

    Galos, Stephan; Klug, Christoph; Rieg, Lorenzo; Sauter, Tobias; Gurgiser, Wolfgang; Kaser, Georg

    2016-04-01

    Long term surface mass balance records of glaciers are of peculiar scientific interest as they reflect the most direct link between the observed glacier changes and the underlying atmospheric forcing. Consequently they provide a unique source of information which is used in a wide range of different models (climate-, mass- or energy balance-, sea level rise- or run-off models). However, both inhomogeneities and unknown error ranges in the observational series limit the usefulness of respective datasets. Hence, the homogenization of long term records, as well as the availability of solid error values can significantly improve the quality of data and is therefore of crucial interest to the community. The surface mass balance of Langenferner / Vedretta Lunga, a small valley glacier in the Italian Eastern Alps, has been measured since the hydrological year 2003/04. The resulting series of annual mass balances was homogenized using a process based mass balance model in order to calculate the annual mass balance for points without stake measurements during the first observation years. A detailed error analysis was performed considering all significant sources of uncertainties involved in the mass balance determination applying the direct glaciological method. The homogenized mass balance values differ from the initial series mainly during the first measurement years when the number of measurements in the upper glacier parts was low and consequently large errors in the spatial extrapolation of measurements were made due to a lack of knowledge about changes in the upper glacier part. Hence the largest errors in mass balance calculation at Langenferner / Vedretta Lunga originate from inaccurate spatial extrapolation of point measurements, while other effects such as errors due to surface roughness play a role on the point scale but are canceled out by the high number of measurement points on the glacier wide scale. A comparison of the surface mass balance to the geodetic

  13. Modelled mass balance of Xibu glacier, Tibetan Plateau: sensitivity to climate change

    OpenAIRE

    Caidong, Caidong; Sorteberg, Asgeir

    2010-01-01

    Due to a lack of in situ measurements, model-based studies of glacier mass balance in the Tibetan Plateau are very limited. An energy-balance model is applied to analyse the mass-balance sensitivity of Xibu glacier, in the Nyainqêntanglha mountain range, to climatic change. A sensitivity calculation shows that a temperature change of ±1°C or a precipitation change of ±35% changes the equilibrium-line altitude (ELA) by 140±125 m. We use a clustering method to link local weather parameter...

  14. SURFACE MASS BALANCE, SUBLIMATION AND SNOW TEMPERATURES AT DOME FUJI STATION, ANTARCTICA, IN 1995

    OpenAIRE

    カメダ, タカオ; アズマ, ノブヒコ; フルカワ, テルオ; アゲタ, ユタカ; タカハシ, シュウヘイ; Takao, KAMEDA; Nobuhiko, AZUMA; Teruo, FURUKAWA; Yutaka, AGETA; Shuhei, TAKAHASHI

    1997-01-01

    This paper focuses on the first year-round observations of surface mass balance, sublimation and snow temperatures at Dome Fuji Station. This station was newly established at the highest point (77°19′01″S, 39°42′12″E; 3810m) in Queen Maud Land, Antarctica by the Japanese Antarctic Research Expedition. It was found that average surface mass balance by the stake method was +2.5g(cm)^ from 25 January 1995 to 30 January 1996 (370 days), of which about 95% of the positive balance was obtained from...

  15. Glacier mass-balance fluctuations in the Pacific Northwest and Alaska, USA

    Science.gov (United States)

    Josberger, E.G.; Bidlake, W.R.; March, R.S.; Kennedy, B.W.

    2007-01-01

    The more than 40 year record of net and seasonal mass-balance records from measurements made by the United States Geological Survey on South Cascade Glacier, Washington, and Wolverine and Gulkana Glaciers, Alaska, shows annual and interannual fluctuations that reflect changes in the controlling climatic conditions at regional and global scales. As the mass-balance record grows in length, it is revealing significant changes in previously described glacier mass-balance behavior, and both inter-glacier and glacier-climate relationships. South Cascade and Wolverine Glaciers are strongly affected by the warm and wet maritime climate of the northeast Pacific Ocean. Their net balances have generally been controlled by winter accumulation, with fluctuations that are strongly related to the Pacific Decadal Oscillation (PDO). Recently, warm dry summers have begun to dominate the net balance of the two maritime glaciers, with a weakening of the correlation between the winter balance fluctuations and the PDO. Non-synchronous periods of positive and negative net balance for each glacier prior to 1989 were followed by a 1989-2004 period of synchronous and almost exclusively negative net balances that averaged -0.8 m for the three glaciers.

  16. Glacier mass-balance fluctuations in the Pacific Northwest and Alaska, USA

    Science.gov (United States)

    Josberger, Edward G.; Bidlake, William R.; March, Rod S.; Kennedy, Ben W.

    2007-10-01

    The more than 40 year record of net and seasonal mass-balance records from measurements made by the United States Geological Survey on South Cascade Glacier, Washington, and Wolverine and Gulkana Glaciers, Alaska, shows annual and interannual fluctuations that reflect changes in the controlling climatic conditions at regional and global scales. As the mass-balance record grows in length, it is revealing significant changes in previously described glacier mass-balance behavior, and both inter-glacier and glacier-climate relationships. South Cascade and Wolverine Glaciers are strongly affected by the warm and wet maritime climate of the northeast Pacific Ocean. Their net balances have generally been controlled by winter accumulation, with fluctuations that are strongly related to the Pacific Decadal Oscillation (PDO). Recently, warm dry summers have begun to dominate the net balance of the two maritime glaciers, with a weakening of the correlation between the winter balance fluctuations and the PDO. Non-synchronous periods of positive and negative net balance for each glacier prior to 1989 were followed by a 1989-2004 period of synchronous and almost exclusively negative net balances that averaged -0.8 m for the three glaciers.

  17. Mass balance of the Amitsulôq ice cap, West Greenland

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Bøggild, Carl Egede; Olesen, Ole B.;

    2007-01-01

    We present detailed mass balance measurements from the Amitsulôq ice cap in West Greenland spanning from 1982 to 1990. The data includes summer and winter balances from 26 stake locations distributed over five transects covering the whole ice cap. The mass balance measurements are combined...... with a recent satellite-derived digital elevation model to calculate the specific balance, which is in turn compared to discharge data from the adjacent Tasersiaq basin. The correlation between specific summer balance and discharge is R2 = 0.93 indicating that the basin discharge is dominated by glacial...... meltwater, linking the hydropower potential of the basin closely to the fate of the adjoining Greenland ice-sheet margin....

  18. Compact Sensitive Piezoelectric Mass Balance for Measurement of Unconsolidated Materials in Space

    Science.gov (United States)

    Sherrit, Stewart; Trebi-Ollennu, Ashitey; Bonitz, Robert; Bar-Cohen, Yoseph; Yen, Jesse T.

    2010-01-01

    In many in-situ instruments information about the mass of the sample could aid in the interpretation of the data and portioning instruments might require an accurate sizing of the sample mass before dispensing the sample. In addition, on potential sample return missions a method to directly assess the captured sample size would be required to determine if the sampler could return or needs to continue attempting to acquire sample. In an effort to meet these requirements piezoelectric balances were developed using flextensional actuators which are capable of monitoring the mass using two methods. A piezoelectric balance could be used to measure mass directly by monitoring the voltage developed across the piezoelectric which is linear with force, or it could be used in resonance to produce a frequency change proportional to the mass change. In this case of the latter, the piezoelectric actuator/balance would be swept in frequency through its fundamental resonance. If a mass is added to the balance the resonance frequency would shift down proportionally to the mass. By monitoring the frequency shift the mass could be determined. This design would allow for two independent measurements of the mass. In microgravity environments spacecraft thrusters could be used to provide acceleration in order to produce the required force for the first technique or to bring the mass into contact with the balance in the second approach. In addition, the measuring actuators, if driven at higher voltages, could be used to fluidize the powder to aid sample movement. In this paper, we outline some of our design considerations and present the results of a few prototype balances that we have developed.

  19. Reconstructing mass balance of Garabashi Glacier (1800–2005 using dendrochronological data

    Directory of Open Access Journals (Sweden)

    E. A. Dolgova

    2013-01-01

    Full Text Available The exploration whether tree-ring data can be effectually applied for the mass balance reconstruction in Caucasus was the main goal of this research. Tree-ring width and maximum density chronologies of pine (Pinus sylvestris L. at seven high-elevation sites in Northern Caucasus were explored for this purpose. As well as in other places of the temperate zone tree- ring width has complex climate signal controlled both temperature and precipitation. Instrumental mass balance records of Garabashi Gglacier started at 1983s. It is well known that Caucasus glaciers intensively retreat in the last decades and according to instrumental data mass balance variations are mostly controlled by the ablation, i.e. summer temperature variations. Maximum density chronology has statistically significant correlation with mass balance due to summer temperature sensitivity and great input of ablation to total mass balance variations. To include in our reconstruction different climatically sensitive parameters, stepwise multiple regression model was used. The strongest relation (r = 0.88; r2 = 0.78; p < 0.05 between two ring-width and one maximum density chronologies was identified. Cross-validation test (r = 0.79; r2 = 0.62; p < 0.05 confirmed model adequacy and it allowed to reconstruct Garabashi Glacier mass balance for 1800–2005ss. Reconstructed and instrumental mass balance values coincide well except the most recent period in 2000s, when the reconstructed mass balance slightly underestimated the real values. However even in this period it remained negative as well as the instrumental records. The bias can be explained by the weak sensitivity of the chronologies to winter precipitation (i.e. accumulation. The tree-ring based mass balance reconstruction was compared with one based on meteorological data (since 1905s. Both reconstructions have good interannual agreement (r = 0.53; p < 0.05 particularly for the period between 1975 and 2005. According to the

  20. Insight into glacier climate interaction: reconstruction of the mass balance field using ice extent data

    Science.gov (United States)

    Visnjevic, Vjeran; Herman, Frédéric; Licul, Aleksandar

    2016-04-01

    With the end of the Last Glacial Maximum (LGM), about 20 000 years ago, ended the most recent long-lasting cold phase in Earth's history. We recently developed a model that describes large-scale erosion and its response to climate and dynamical changes with the application to the Alps for the LGM period. Here we will present an inverse approach we have recently developed to infer the LGM mass balance from known ice extent data, focusing on a glacier or ice cap. The ice flow model is developed using the shallow ice approximation and the developed codes are accelerated using GPUs capabilities. The mass balance field is the constrained variable defined by the balance rate β and the equilibrium line altitude (ELA), where c is the cutoff value: b = max(βṡ(S(z) - ELA), c) We show that such a mass balance can be constrained from the observed past ice extent and ice thickness. We are also investigating several different geostatistical methods to constrain spatially variable mass balance, and derive uncertainties on each of the mass balance parameters.

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

    DEFF Research Database (Denmark)

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

    Global warming is predicted to have a profound impact on the Greenland Ice Sheet (GrIS) and its contribution to future sea-level rise. The GrIS has seen dramatic changes over the last two decades and mass loss has been accelerating, owing to a combination of increased runoff and discharge of ice ...

  2. A high-resolution record of Greenland mass balance

    Science.gov (United States)

    McMillan, Malcolm; Leeson, Amber; Shepherd, Andrew; Briggs, Kate; Armitage, Thomas W. K.; Hogg, Anna; Kuipers Munneke, Peter; Broeke, Michiel; Noël, Brice; Berg, Willem Jan; Ligtenberg, Stefan; Horwath, Martin; Groh, Andreas; Muir, Alan; Gilbert, Lin

    2016-07-01

    We map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat-2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) with airborne measurements. With the aid of regional climate and firn modeling, we compute high spatial and temporal resolution records of Greenland mass evolution, which correlate (R = 0.96) with monthly satellite gravimetry and reveal glacier dynamic imbalance. During 2011-2014, Greenland mass loss averaged 269 ± 51 Gt/yr. Atmospherically driven losses were widespread, with surface melt variability driving large fluctuations in the annual mass deficit. Terminus regions of five dynamically thinning glaciers, which constitute less than 1% of Greenland's area, contributed more than 12% of the net ice loss. This high-resolution record demonstrates that mass deficits extending over small spatial and temporal scales have made a relatively large contribution to recent ice sheet imbalance.

  3. Mass Balance. Operational Control Tests for Wastewater Treatment Facilities. Instructor's Manual [and] Student Workbook.

    Science.gov (United States)

    Carnegie, John W.

    This module describes the process used to determine solids mass and location throughout a waste water treatment plant, explains how these values are used to determine the solids mass balance around single treatment units and the entire system, and presents calculations of solids in pounds and sludge units. The instructor's manual contains a…

  4. The pattern of anthropogenic signal emergence in Greenland Ice Sheet surface mass balance

    NARCIS (Netherlands)

    Fyke, J.G.; Vizcaino, M.; Lipscomb, W.H.

    2014-01-01

    Surface mass balance (SMB) trends influence observed Greenland Ice Sheet (GrIS) mass loss, but the component of these trends related to anthropogenic forcing is unclear. Here we study the simulated spatial pattern of emergence of an anthropogenically derived GrIS SMB signal between 1850 and 2100 usi

  5. Greenland high-elevation mass balance: inference and implication of reference period (1961–90) imbalance

    OpenAIRE

    Colgan, W.; J. Box; Andersen, M.; Fettweis, Xavier; Csatho, B.; Fausto, R.; As, D.; Wahr, J.

    2015-01-01

    We revisit the input–output mass budget of the high-elevation region of the Greenland ice sheet evaluated by the Program for Arctic Regional Climate Assessment (PARCA). Our revised reference period (1961–90) mass balance of 54 48 Gt a–1 is substantially greater than the 0 21 Gt a–1 assessed by PARCA, but consistent with a recent, fully independent, input–output estimate of high-elevation mass balance (41 61 Gt a–1). Together these estimates infer a reference period high-elevation specif...

  6. Can we close the long term mass balance equation for pollutants in highway ponds?

    OpenAIRE

    Bentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael R.

    2007-01-01

    The paper discusses the prospects of finding the long term mass balance on basis of short term simulations. A step in this process is to see to which degree the mass balance equation can be closed by measurements. Accordingly the total accumulation of heavy metals and PAH's in 8 Danish detention ponds only receiving runoff from highways have been measured. The result shows that the incoming mass of heavy metals from short term runoff events is accumulated. This is not observable in the same m...

  7. Use of mass and toxicity balances in risk-based corrective action decisions at contaminated sites

    International Nuclear Information System (INIS)

    The contaminated groundwater at a sour gas plant facility was studied to identify the chemicals of environmental concern. Simple mass balance principles were used to determine the proportion of organic carbon, organic nitrogen and MicrotoxR toxicity that can be attributed to two process chemicals that have contaminated several sour gas plants in western Canada. The two process chemicals are sulfolane and diisopropanolamine (DIPA). The organic carbon balance was calculated by determining the molar contribution of sulfolane and DIPA relative to the mass of carboxylic acid-corrected dissolved organic carbon. Organic carbon balances ranged from 44 to 96 per cent. The organic nitrogen balance was calculated by determining the molar contribution of DIPA relative to the mass of ammonium ion-corrected dissolved Kjeldahl nitrogen. The nitrogen balances were highly variable between 8 to 48 per cent for samples with organic nitrogen concentrations between 10 and 32 mg/L. The MicrotoxR toxicity balance was calculated by determining the proportions of toxicity that could be accounted for by pure phase sulfolane and DIPA. The MicrotoxR toxicity balance for samples that showed significant toxicity ranged from 71 to 122 per cent

  8. Present and future mass standards for the LNE watt balance and the future dissemination of the mass unit in France

    Science.gov (United States)

    Pinot, Patrick; Beaudoux, Florian; Bentouati, Djilali; Espel, Patrick; Madec, Tanguy; Thomas, Matthieu; Silvestri, Zaccari; Ziane, Djamel; Piquemal, François

    2016-08-01

    The value of the Planck constant h was determined in 2014 by means of the LNE watt balance experiment. The relative standard uncertainty was 31 parts in 108. This first determination was performed in air with a 500 g mass standard made from XSH Alacrite. The main uncertainty components in air associated with the mass involve the calibration, the mass stability, the buoyancy correction and the magnetic interaction correction. The combined relative uncertainty due to the mass is 7.2 parts in 108. The use in 2016 of a mass standard made from platinum iridium alloy significantly reduces the component of uncertainty arising from the mass standard for a Planck constant measurement either in air or under vacuum. The relative uncertainty due to this contribution is estimated to be about 3 parts in 108 in air and one part in 108 under vacuum. The future system for the dissemination of the mass unit using the LNE watt balance will be based on a primary realization with three 500 g mass standards made from platinum–iridium alloy, pure iridium and Udimet 720 respectively, coupled with a pool of kilograms made from different materials. Pure iridium and Udimet 720 are new materials to make reference mass standards proposed by CNAM and LNE respectively and have never been used by any NMI for manufacturing mass standards until now. Some new results concerning their surface behavior are given.

  9. Assessing streamflow sensitivity to variations in glacier mass balance

    Science.gov (United States)

    O'Neel, Shad; Hood, Eran; Arendt, Anthony; Sass, Louis

    2014-01-01

    The mountains ringing the Gulf of Alaska (GOA) receive upwards of 4–8 m yr−1 of precipitation (Simpson et al.2005; Weingartner et al. 2005; O’Neel 2012), much of which runs off into productive coastal waters. The alpine landscape is heavily glacierized, and storage and turnover of water by glaciers substantially influences the regional surface water balance (Neal et al. 2010). In turn, the land-to-ocean flux of freshwater impacts the biogeochemistry, physical oceanography, freshwater and marine ecology of the downstream components of the GOA ecosystem (e.g., Royer et al. 2001; Hood and Scott 2008). In this way, the links between terrestrial and ocean ecosystems along the GOA have widespread impacts on regional socioeconomic issues including water and hydropower resources, fish populations, and sea level change (Dorava and Milner 2000; Royer and Grosch 2006; Cherry et al. 2010; Gardner et al. 2013). Moreover, predicting future changes in physical, chemical and biological processes in near-shore ecosystems along the GOA hinges, in part, on developing a robust understanding of water storage and transfer by glaciers through streams to the ocean.

  10. Balance Mechanism Design of Single Cylinder Engine Based on Continuous Mass Distribution of Connecting Rod

    Institute of Scientific and Technical Information of China (English)

    YANG Chen; HAO Zhiyong; ZHENG Guangtai

    2009-01-01

    For a single cylinder engine, the total unbalanced inertial forces occur in the engine block, which results in engine's vibration and deteriorated noise. In order to eliminate the unbalanced forces, counterweight and primary balance shaft should be attached to the cylinder block so that engine durability and ride comfortability may be fur-ther improved. Traditionally one third of connecting rod assembly's mass is treated as reciprocating mass, and two thirds as rotating mass when designing balance mechanism. In this paper, a new method based on the multibody dynamics simulation is introduced to separate the reciprocating mass and rotating mass of connecting rod assembly. The model consists of crankshaft, connecting rod, piston and the simulation is performed subsequently. According to the simulation results of the main bearing loads, the reciprocating mass and rotating mass are separated. Finally a new balance mechanism is designed and simulation results show that it completely balances inertial forces to im-prove the engine's noise vibration and harshness performance.

  11. Trends and variability in the global dataset of glacier mass balance

    Science.gov (United States)

    Medwedeff, William G.; Roe, Gerard H.

    2016-06-01

    Glacier mass balance (i.e., accumulation and ablation) is the most direct connection between climate and glaciers. We perform a comprehensive evaluation of the available global network of mass-balance measurements. Each mass-balance time series is decomposed into a trend and the variability about that trend. Observed variability ranges by an order of magnitude, depending on climate setting (i.e., maritime vs continental). For the great majority of glaciers, variability is well characterized by normally distributed, random fluctuations that are uncorrelated between seasons, or in subsequent years. The magnitude of variability for both summer and winter is well correlated with mean wintertime balance, which reflects the climatic setting. Collectively, summertime variability exceeds wintertime variability, except for maritime glaciers. Trends in annual mass balance are generally negative, driven primarily by summertime changes. Approximately 25 % of annual-mean records show statistically significant negative trends when judged in isolation. In aggregate, the global trend is negative and significant. We further evaluate the magnitude of trends relative to the variability. We find that, on average, trends are approximately -0.2 standard deviations per decade, although there is a broad spread among individual glaciers. Finally, for two long records we also compare mass-balance trends and variability with nearby meteorological stations. We find significant differences among stations meaning caution is warranted in interpreting any point measurement (such as mass balance) as representative of region-wide behavior. By placing observed trends in the context of natural variability, the results are useful for interpreting past glacial history, and for placing constraints on future predictability.

  12. The influence of changes in glacier extent and surface elevation on modeled mass balance

    Directory of Open Access Journals (Sweden)

    F. Paul

    2010-12-01

    Full Text Available Glaciers are widely recognized as unique demonstration objects for climate change impacts, mostly due to the strong change of glacier length in response to small climatic changes. However, glacier mass balance as the direct response to the annual atmospheric conditions can be better interpreted in meteorological terms. When the climatic signal is deduced from long-term mass balance data, changes in glacier geometry (i.e. surface extent and elevation must be considered as such adjustments form an essential part of the glacier reaction to new climatic conditions. In this study, a set of modelling experiments is performed to assess the influence of changes in glacier geometry on mass balance for constant climatic conditions. The calculations are based on a simplified distributed energy/mass balance model in combination with information on glacier extent and surface elevation for the years 1850 and 1973/1985 for about 60 glaciers in the Swiss Alps. The results reveal that over this period about 50–70% of the glacier reaction to climate change (here a one degree increase in temperature is "hidden" in the geometric adjustment, while only 30–50% can be measured as the long-term mean mass balance. For larger glaciers, the effect of the areal change is partly reduced by a lowered surface elevation, which results in a slightly more negative balance despite a potential increase of topographic shading. In view of several additional reinforcement feedbacks that are observed in periods of strong glacier decline, it seems that the climatic interpretation of long-term mass balance data is rather complex.

  13. The influence of changes in glacier extent and surface elevation on modeled mass balance

    Directory of Open Access Journals (Sweden)

    F. Paul

    2010-06-01

    Full Text Available Glaciers are widely recognized as unique demonstration objects for climate change impacts, mostly due to the strong change of glacier length in response to small climatic changes. However, glacier mass balance as the direct response to the annual atmospheric conditions can be better interpreted in meteorological terms. When the climatic signal is deduced from long-term mass balance data, changes in glacier geometry (i.e. surface extent and elevation must be considered as such adjustments form an essential part of the glacier reaction to new climatic conditions. In this study, a set of modeling experiments is performed to assess the influence of changes in glacier geometry on mass balance for constant climatic conditions. The calculations are based on a simplified distributed energy/mass balance model in combination with information on glacier extent and surface elevation for the years 1850 and 1973/1985 for a larger sample of glaciers in the Swiss Alps. The results reveal that about 50–70% of the glacier reaction to climate change (here a one degree increase in temperature is "hidden" in the geometric adjustment, while only 30–50% can be measured as the long-term mean mass balance. Thereby, changes in glacier extent alone have an even stronger effect, but they are partly compensated for by a lowered surface elevation which gives on average a slightly more negative balance despite an increase of topographic shading. In view of several additional reinforcement feedbacks that are observed in periods of strong glacier decline, it seems that the climatic interpretation of mass balance data is also rather complex.

  14. Overview of Ice-Sheet Mass Balance and Dynamics from ICESat Measurements

    Science.gov (United States)

    Zwally, H. Jay

    2010-01-01

    The primary purpose of the ICESat mission was to determine the present-day mass balance of the Greenland and Antarctic ice sheets, identify changes that may be occurring in the surface-mass flux and ice dynamics, and estimate their contributions to global sea-level rise. Although ICESat's three lasers were planned to make continuous measurements for 3 to 5 years, the mission was re-planned to operate in 33-day campaigns 2 to 3 times each year following failure of the first laser after 36 days. Seventeen campaigns were conducted with the last one in the Fall of 2009. Mass balance maps derived from measured ice-sheet elevation changes show that the mass loss from Greenland has increased significantly to about 170 Gt/yr for 2003 to 2007 from a state of near balance in the 1990's. Increased losses (189 Gt/yr) from melting and dynamic thinning are over seven times larger'than increased gains (25 gt/yr) from precipitation. Parts of the West Antarctic ice sheet and the Antarctic Peninsula are losing mass at an increasing rate, but other parts of West Antarctica and the East Antarctic ice sheet are gaining mass at an increasing rate. Increased losses of 35 Gt/yr in Pine Island, Thwaites-Smith, and Marie-Bryd.Coast are more than balanced by gains in base of Peninsula and ice stream C, D, & E systems. From the 1992-2002 to 2003-2007 period, the overall mass balance for Antarctica changed from a loss of about 60 Gt/yr to near balance or slightly positive.

  15. Mass-balance Approach to Interpreting Weathering Reactions in Watershed Systems

    Science.gov (United States)

    Bricker, O. P.; Jones, B. F.; Bowser, C. J.

    2003-12-01

    The mass-balance approach is conceptually simple and has found widespread applications in many fields over the years. For example, chemists use mass balance (Stumm and Morgan, 1996) to sum the various species containing an element in order to determine the total amount of that element in the system (free ion, complexes). Glaciologists use mass balance to determine the changes in mass of glaciers ( Mayo et al., 1972 and references therein). Groundwater hydrologists use this method to interpret changes in water balance in groundwater systems ( Rasmussen and Andreasen, 1959; Bredehoeft et al., 1982; Heath, 1983; Konikow and Mercer, 1988; Freeze and Cherry, 1979; Ingebritsen and Sanford, 1998). This method has also been used to determine changes in chemistry along a flow path ( Plummer et al., 1983; Bowser and Jones, 1990) and to quantify lake hydrologic budgets using stable isotopes ( Krabbenhoft et al., 1994). Blum and Erel (see Chapter 5.12) discuss the use of strontium isotopes, Chapelle (see Chapter 5.14) treats carbon isotopes in groundwater, and Kendall and Doctor (see Chapter 5.11) and Kendall and McDonnell (1998) discuss the use of stable isotopes in mass balance. Although the method is conceptually simple, the parameters that define a mass balance are not always easy to measure. Watershed investigators use mass balance to determine physical and chemical changes in watersheds ( Garrels and Mackenzie, 1967; Plummer et al., 1991; O'Brien et al., 1997; Drever, 1997). Here we focus on describing the mass-balance approach to interpret weathering reactions in watershed systems including shallow groundwater.Because mass balance is simply an accounting of the flux of material into a system minus the flux of material out of the system, the geochemical mass-balance approach is well suited to interpreting weathering reactions in watersheds (catchments) and in other environmental settings (Drever, 1997). It is, perhaps, the most accurate and reliable way of defining

  16. An improved technique for the reconstruction of former glacier mass-balance and dynamics

    Science.gov (United States)

    Carr, Simon; Coleman, Christopher

    2007-11-01

    The recognition of past glacier extent and dynamics is a fundamental aspect of investigations of the climatic sensitivity of glaciers, especially when examining short-lived climate events such as the Younger Dryas or Little Ice Age. Existing approaches to the reconstruction of glacier form and dynamics depend on speculative reasoning of key glacier dynamic parameters, including the role of basal slip and subglacial deformation in glacier mass-transfer. This study reviews approaches to glacier reconstruction, derivation of former glacier equilibrium line altitudes (ELA's) and estimation of mass-balance and dynamics, concluding that most reconstructions of glacier mass-balance are compromised by a lack of glaciological considerations. An alternative approach to glacier reconstruction is presented, demonstrated and discussed, by which an empirical relationship between ablation gradient and mass loss at the ELA is used to derive mass-balance, mass-flux through the ELA and average balance velocity at the ELA. This 'glaciological' approach is applied to four reconstructed glaciers to test previous interpretations that each reflects Younger Dryas glaciation in the UK. The study concludes that this approach provides a more robust technique for reconstructing former glacier dynamics, and may be applied to test geomorphological interpretations of former mountain glaciation.

  17. Investigating glacial mass balance variability around the Prince Gustav Channel

    Science.gov (United States)

    Royston, Samantha; Gudmundsson, Hilmar; Clarke, Lucy; Fox, Adrian

    2015-04-01

    Glaciers on the Antarctic Peninsula have shown a varied response to recent climatic change. Most commonly, AP tidewater glaciers have retreated at the calving front and their flow rate has accelerated, increasing the contribution to sea level rise. Here, we utilise the results from a new photogrammetric technique that unlocks the archives of aerial photography from the 1940's to present, to investigate the driving mechanisms of glacier mass change on the AP over this period. Surface DEMs at different epochs have been derived using the new technique for a number of individual glacier basins. A higher-order vertically-integrated ice stream model is used to investigate the driving mechanisms of change for the area around the Prince Gustav Channel, incorporating basins covered by the new datasets. The Prince Gustav Ice Shelf collapsed in January 1995, followed by significant frontal retreat and speed up of its tributary glaciers. Additionally, significant changes have been observed for non-tributary glaciers such as Whisky Glacier on James Ross Island. Here, we investigate the sensitivity of this region's glaciers to ice shelf collapse, atmospheric and oceanic variability.

  18. Re-analysis of Alaskan benchmark glacier mass-balance data using the index method

    Science.gov (United States)

    Van Beusekom, Ashely E.; O'Nell, Shad R.; March, Rod S.; Sass, Louis C.; Cox, Leif H.

    2010-01-01

    At Gulkana and Wolverine Glaciers, designated the Alaskan benchmark glaciers, we re-analyzed and re-computed the mass balance time series from 1966 to 2009 to accomplish our goal of making more robust time series. Each glacier's data record was analyzed with the same methods. For surface processes, we estimated missing information with an improved degree-day model. Degree-day models predict ablation from the sum of daily mean temperatures and an empirical degree-day factor. We modernized the traditional degree-day model and derived new degree-day factors in an effort to match the balance time series more closely. We estimated missing yearly-site data with a new balance gradient method. These efforts showed that an additional step needed to be taken at Wolverine Glacier to adjust for non-representative index sites. As with the previously calculated mass balances, the re-analyzed balances showed a continuing trend of mass loss. We noted that the time series, and thus our estimate of the cumulative mass loss over the period of record, was very sensitive to the data input, and suggest the need to add data-collection sites and modernize our weather stations.

  19. Evaluation of a mass-balance approach to determine consumptive water use in northeastern Illinois

    Science.gov (United States)

    Mills, Patrick C.; Duncker, James J.; Over, Thomas M.; Marian Domanski,; ,; Engel, Frank

    2014-01-01

    A principal component of evaluating and managing water use is consumptive use. This is the portion of water withdrawn for a particular use, such as residential, which is evaporated, transpired, incorporated into products or crops, consumed by humans or livestock, or otherwise removed from the immediate water environment. The amount of consumptive use may be estimated by a water (mass)-balance approach; however, because of the difficulty of obtaining necessary data, its application typically is restricted to the facility scale. The general governing mass-balance equation is: Consumptive use = Water supplied - Return flows.

  20. Seasonal and annual mass balances of Mera and Pokalde glaciers (Nepal Himalaya since 2007

    Directory of Open Access Journals (Sweden)

    P. Wagnon

    2013-07-01

    Full Text Available In the Everest region, Nepal, ground-based monitoring programs were started on the debris-free Mera Glacier (27.7° N, 86.9° E; 5.1 km2, 6420 to 4940 m a.s.l. in 2007 and on the small Pokalde Glacier (27.9° N, 86.8° E; 0.1 km2, 5690 to 5430 m a.s.l., ∼ 25 km North of Mera Glacier in 2009. These glaciers lie on the southern flank of the central Himalaya under the direct influence of the Indian monsoon and receive more than 80% of their annual precipitation in summer (June to September. Despite a large inter-annual variability with glacier-wide mass balances ranging from −0.77± 0.40 m w.e. in 2011–2012 (Equilibrium-line altitude (ELA at ∼ 6055 m a.s.l. to + 0.46 ± 0.40 m w.e. in 2010–2011 (ELA at ∼ 5340 m a.s.l., Mera Glacier has been shrinking at a moderate mass balance rate of −0.10± 0.40 m w.e. yr−1 since 2007. Ice fluxes measured at two distinct transverse cross sections at ∼ 5350 m a.s.l. and ∼ 5520 m a.s.l. confirm that the mean state of this glacier over the last one or two decades corresponds to a limited mass loss, in agreement with remotely-sensed region-wide mass balances of the Everest area. Seasonal mass balance measurements show that ablation and accumulation are concomitant in summer which in turn is the key season controlling the annual glacier-wide mass balance. Unexpectedly, ablation occurs at all elevations in winter due to wind erosion and sublimation, with remobilized snow likely being sublimated in the atmosphere. Between 2009 and 2012, the small Pokalde Glacier lost mass more rapidly than Mera Glacier with respective mean glacier-wide mass balances of −0.72 and −0.26 ± 0.40 m w.e. yr−1. Low-elevation glaciers, such as Pokalde Glacier, have been usually preferred for in-situ observations in Nepal and more generally in the Himalayas, which may explain why compilations of ground-based mass balances are biased toward negative values compared with the regional mean under the present-day climate.

  1. Hybrid inventory, gravimetry and altimetry (HIGA) mass balance product for Greenland and the Canadian Arctic

    DEFF Research Database (Denmark)

    Colgan, W.; Abdalati, W.; Citterio, M.;

    2015-01-01

    We present a novel inversion algorithm that generates a mass balance field that is simultaneously consistent with independent observations of glacier inventory derived from optical imagery, cryosphere-attributed mass trends derived from satellite gravimetry, and ice surface elevation trends derived...... from airborne and satellite altimetry. We use this algorithm to assess mass balance across Greenland and the Canadian Arctic over the Sep-2003 to Oct-2009 period at 26 km resolution. We evaluate local algorithm-inferred mass balance against forty in situ point observations. This evaluation yields...... an RMSE of 0.15 mWE/a, and highlights a paucity of in situ observations from regions of high dynamic mass loss and peripheral glaciers. We assess mass losses of 212 ± 67 Gt/a to the Greenland ice sheet proper, 38 ± 11 Gt/a to peripheral glaciers in Greenland, and 42 ± 11 Gt/a to glaciers in the Canadian...

  2. Mass-Balance Constraints on Nutrient Cycling in Tropical Seagrass Beds

    NARCIS (Netherlands)

    Erftemeijer, P.L.A.; Middelburg, J.J.

    1995-01-01

    A relatively simple mass balance model is presented to study the cycling of nutrients (nitrogen and phosphorus) in tropical seagrass beds. The model is based on quantitative data on nutrient availability, seagrass primary production, community oxygen metabolism, seagrass tissue nutrient contents, se

  3. Combining satellite altimetry and gravimetry data to improve Antarctic mass balance and gia estimates

    NARCIS (Netherlands)

    Gunter, B.C.; Didova, O.; Riva, R.E.M.; van den Broeke, M.R.; Ligtenberg, S.R.M.; Lenaerts, J.T.M.; King, M.; Urban, T.

    2012-01-01

    This study explores an approach that simultaneously estimates Antarctic mass balance and glacial isostatic adjustment (GIA) through the combination of satellite gravity and altimetry data sets. The results improve upon previous efforts by incorporating reprocessed data sets over a longer period of t

  4. THE LAKE MICHIGAN MASS BALANCE PROJECT: QUALITY ASSURANCE PLAN FOR MATHEMATICAL MODELLING

    Science.gov (United States)

    This report documents the quality assurance process for the development and application of the Lake Michigan Mass Balance Models. The scope includes the overall modeling framework as well as the specific submodels that are linked to form a comprehensive synthesis of physical, che...

  5. Elevation change and remote-sensing mass-balance methods on the Greenland ice sheet

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Reeh, Niels; Christensen, Erik Lintz;

    differential GPS instruments and corrected for pitch, roll and crab using an Inertial Navigation System. Knowledge of elevation change and ice thickness alone does not provide mass balance, but when combined with the surface velocity field obtained from satellite repeat-track interferometric synthetic aperture...

  6. Monthly solutions of ice sheet mass balance at basin scale – and their associated uncertainties

    DEFF Research Database (Denmark)

    Sørensen, Louise Sandberg; Barletta, Valentina Roberta; Forsberg, René

    2012-01-01

    There are still discrepancies in published ice sheet mass balance results, even between ones based on the same data sets. It can be difficult to conclude from where the discrepancies arise, and it is therefore important to cross calibrate methods, data and models in order to determine...

  7. Future climate warming increases Greenland ice sheet surface mass balance variability

    NARCIS (Netherlands)

    Fyke, J.G.; Vizcaino, M.; Lipscomb, W.; Price, S.

    2014-01-01

    The integrated surface mass balance (SMB) of the Greenland ice sheet (GrIS) has large interannual variability. Long-term future changes to this variability will affect GrIS dynamics, freshwater fluxes, regional oceanography, and detection of changes in ice volume trends. Here we analyze a simulated

  8. Mass Balance Model, A study of contamination effects in AMS 14C sample analysis

    NARCIS (Netherlands)

    Prokopiou, Markella

    2010-01-01

    In this training thesis a background correction analysis, also known as mass balance model, was implemented to study the contamination effects in AMS 14C sample processing. A variety of backgrounds and standards with sizes ranging from 50 μg C to 1500 μg

  9. Transdermal administration of radiolabelled [14C]rotigotine by a patch formulation: A mass balance trial

    NARCIS (Netherlands)

    Cawello, W.; Wolff, H.M.; Meuling, W.J.A.; Horstmann, R.; Braun, M.

    2007-01-01

    Background and objective: The dopamine agonist rotigotine has been formulated in a silicone-based transdermal system for once-daily administration. The objective of the present study was to characterise the mass balance of rotigotine in humans after administration of a single transdermal patch conta

  10. Computer Aided Mass Balance Analysis for AC Electric Arc Furnace Steelmaking

    Institute of Scientific and Technical Information of China (English)

    (ü)nal Camdali; Murat Tunc

    2005-01-01

    A mass balance analysis was undertaken for liquid steel production using a computer program specially developed for the AC electric arc furnace at an important alloy steel producer in Turkey. The data obtained by using the computer program were found to be very close to the actual production ones.

  11. Nitrate Removal in Two Relict Oxbow Urban Wetlands: A 15N Mass-balance Approach

    Science.gov (United States)

    A 15N-tracer method was used to quantify nitrogen (N) removal processes in two relict oxbow wetlands located adjacent to the Minebank Run restored stream reach in Baltimore County (Maryland, USA) during summer 2009 and early spring 2010. A mass-balance approach was used to determ...

  12. High variability of climate and surface mass balance induced by Antarctic ice rises

    NARCIS (Netherlands)

    Lenaerts, Jan; Brown, Joel; van den Broeke, Michiel; Matsuoka, Kenichi; Drews, Reinhard; Callens, Denis; Philippe, Morgane; Gorodetskaya, I.V.; van Meijgaard, E.; Tijm - Reijmer, Catharina; Pattyn, F.; van Lipzig, N.P.M.

    2014-01-01

    Ice rises play key roles in buttressing the neighbouring ice shelves and potentially provide palaeoclimate proxies from ice cores drilled near their divides. Little is known, however, about their influence on local climate and surface mass balance (SMB). Here we combine 12 years (2001–12) of regiona

  13. Microbial transglutaminase production by Streptoverticillium mobaraense: Analysis of amino acid metabolism using mass balances

    NARCIS (Netherlands)

    Zhu, Y.; Rinzema, A.; Bonarius, H.P.J.; Tramper, J.; Bol, J.

    1998-01-01

    Metabolic flows, especially those of amino acids, were determined and analyzed at different stages of a batch fermentation for microbial transglutaminase production by Streptoverticillium mobaraense. The method is mainly based on mass balances and measurements of amino acids and other metabolites. T

  14. Influence of Persistent Wind Scour on the Surface Mass Balance of Antarctica

    Science.gov (United States)

    Das, Indrani; Bell, Robin E.; Scambos, Ted A.; Wolovick, Michael; Creyts, Timothy T.; Studinger, Michael; Fearson, Nicholas; Nicolas, Julien P.; Lenaerts, Jan T. M.; vandenBroeke, Michiel R.

    2013-01-01

    Accurate quantification of surface snow accumulation over Antarctica is a key constraint for estimates of the Antarctic mass balance, as well as climatic interpretations of ice-core records. Over Antarctica, near-surface winds accelerate down relatively steep surface slopes, eroding and sublimating the snow. This wind scour results in numerous localized regions (Antarctica. The scour zones are persistent because they are controlled by bedrock topography. On the basis of our Dome A observations, we develop an empirical model to predict wind-scour zones across the Antarctic continent and find that these zones are predominantly located in East Antarctica. We estimate that approx. 2.7-6.6% of the surface area of Antarctica has persistent negative net accumulation due to wind scour, which suggests that, across the continent, the snow mass input is overestimated by 11-36.5 Gt /yr in present surface-mass-balance calculations.

  15. The seasonal in-situ mass balance, temperature and precipitation of Yala Glacier, Langtang Valley, Nepal, from 2011 to 2015

    Science.gov (United States)

    Stumm, Dorothea; Fujita, Koji; Gurung, Tika; Joshi, Sharad; Litt, Maxime; Shea, Joseph; Sherpa, Mingma; Sinisalo, Anna; Wagnon, Patrick

    2016-04-01

    In-situ glacier mass balance measurements are still scarce in the Hindu Kush Himalayan (HKH) region and little is known about the seasonal balances. The glaciers in the Nepalese Himalaya have been considered summer accumulation glacier types because of the assumption that the majority of the accumulation occurs in the summer months during the monsoon. The glacier mass balance of Yala Glacier in the Langtang Valley of Nepal has been measured using the glaciological method since autumn 2011. Stakes were measured biannually in pre- and post-monsoon, usually in early May and in November, respectively. The measured mass balance gradient for the summer balance was larger than the winter balance, which is typical for glaciers with distinct ablation and accumulation seasons. On Yala Glacier, the summer balance was negative, and the winter balance was positive in all years with measurements. However, the annual net balance was negative for all four mass balance years from 2011 to 2015. The mass balances were further compared to temperature and precipitation data measured at nearby climate stations during the same time periods. In October 2013 and 2014, the Central Himalayas received large amounts of precipitation brought by the cyclones Phailin and Hudhud. These precipitation events contributed to the summer balance since the measurements were taken after the cyclones passed. In conclusion, on Yala Glacier accumulation processes dominated ablation processes during the winter, and ablation processes dominated during the summer, which could be explained by the low elevation range of Yala Glacier and precipitation from westerlies in the winter. Hence, this should be kept in mind when using the term 'summer accumulation glacier' for Yala Glacier. For future research in the HKH region, seasonal mass balances should be measured, and the processes impacting the mass balance and the role of winter precipitation should be investigated for other glaciers in the HKH region.

  16. Processes governing the mass balance of Chhota Shigri Glacier (Western Himalaya, India assessed by point-scale surface energy balance measurements

    Directory of Open Access Journals (Sweden)

    M. F. Azam

    2014-06-01

    Full Text Available Recent studies revealed that Himalayan glaciers have been shrinking at an accelerated rate since the beginning of the 21st century. However the climatic causes for this shrinkage remain unclear given that surface energy balance studies are almost nonexistent in this region. In this study, a point-scale surface energy balance analysis was performed using in-situ meteorological data from the ablation zone of Chhota Shigri Glacier over two separate periods (August 2012 to February 2013 and July to October 2013 in order to understand the response of mass balance to climate change. Energy balance numerical modeling provides quantification of the surface energy fluxes and identification of the factors affecting glacier mass balance. The computed ablation was validated by stake observations. During summer-monsoon period, net radiation was the primary component of the surface energy balance with 82% of the total heat flux which was complimented with turbulent sensible and latent heat fluxes with a share of 13% and 5%, respectively. A striking feature of energy balance is the positive turbulent latent heat flux, thus condensation or re-sublimation of moist air at the glacier surface takes place, during summer-monsoon period which is characterized by relatively high air temperature, high relative humidity and almost permanent melting surface. The impact of Indian summer monsoon on Chhota Shigri Glacier mass balance has also been assessed. This analysis demonstrates that the intensity of snowfall events during the summer-monsoon season plays a key role on surface albedo, in turn on melting, and thus is among the most important drivers controlling the annual mass balance of the glacier. Summer-monsoon air temperature, controlling the precipitation phase (rain vs. snow and thus albedo, counts, indirectly, also among the most important drivers for the glacier mass balance.

  17. Mass balance performance of a 300 MW CFB boiler burning blend fuel with different mixing ratio

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yang; Chao, Junnan; Yang, Hairui; Lv, Junfu; Zhang, Hai; Liu, Qing; Yue, Guangxi [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering; Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering

    2013-07-01

    In order to predict the mass balance of a 300 MWe circulating fluidized bed (CFB) boiler under design process, the ash formation and attrition characteristic of the design fuel mixed with gangue, middling and slime were investigated with Tsinghua own process. In addition, the mass balance in this CFB boiler was simulated with 1D mass balance model, giving the ratio of the ashes, particle size distribution of circulating solid materials and solid circulating rat, Gs. By comparing the residence time distribution and the burn out time required for different size, the minimum bed pressure drop (BPD) or bed inventory in the furnace was determined for different mixing ratio among the three coals. The results show that under each mixing ratio, the solid circulating flux and solid suspension density in the upper furnace can meet the requirement of heating transfer. However, the minimum BPD or bed inventory required to meet the burn out time of the coarse solids was different. For in the case with the ratio among gangue, middling and slime as 5:3:2, the lowest value is 12 kPa, which will cause serious erosion and more power consumption. Because the middling has lower ash content, higher reactivity and better ash formation, increasing the proportion of the middling (1:5:4) will decrease the BPD greatly to 5 kPa, not only meet the requirements of material balance and burn time for coarse solids easily, but also realize the energy saving operation.

  18. Gulkana Glacier, Alaska-Mass balance, meteorology, and water measurements, 1997-2001

    Science.gov (United States)

    March, Rod S.; O'Neel, Shad

    2011-01-01

    The measured winter snow, maximum winter snow, net, and annual balances for 1997-2001 in the Gulkana Glacier basin are determined at specific points and over the entire glacier area using the meteorological, hydrological, and glaciological data. We provide descriptions of glacier geometry to aid in estimation of conventional and reference surface mass balances and descriptions of ice motion to aid in the understanding of the glacier's response to its changing geometry. These data provide annual estimates for area altitude distribution, equilibrium line altitude, and accumulation area ratio during the study interval. New determinations of historical area altitude distributions are given for 1900 and annually from 1966 to 2001. As original weather instrumentation is nearing the end of its deployment lifespan, we provide new estimates of overlap comparisons and precipitation catch efficiency. During 1997-2001, Gulkana Glacier showed a continued and accelerated negative mass balance trend, especially below the equilibrium line altitude where thinning was pronounced. Ice motion also slowed, which combined with the negative mass balance, resulted in glacier retreat under a warming climate. Average annual runoff augmentation by glacier shrinkage for 1997-2001 was 25 percent compared to the previous average of 13 percent, in accordance with the measured glacier volume reductions.

  19. Exploring uncertainty in glacier mass balance modelling with Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    H. Machguth

    2008-06-01

    Full Text Available By means of Monte Carlo simulations we calculated uncertainty in modelled cumulative mass balance over 400 days at one particular point on the tongue of Morteratsch Glacier, Switzerland, using a glacier energy balance model of intermediate complexity. Before uncertainty assessment, the model was tuned to observed mass balance for the investigated time period and its robustness was tested by comparing observed and modelled mass balance over 11 years, yielding very small deviations. Both systematic and random uncertainties are assigned to twelve input parameters and their respective values estimated from the literature or from available meteorological data sets. The calculated overall uncertainty in the model output is dominated by systematic errors and amounts to 0.7 m w.e. or approximately 10% of total melt over the investigated time span. In order to provide a first order estimate on variability in uncertainty depending on the quality of input data, we conducted a further experiment, calculating overall uncertainty for different levels of uncertainty in measured global radiation and air temperature. Our results show that the output of a well calibrated model is subject to considerable uncertainties, in particular when applied for extrapolation in time and space where systematic errors are likely to be an important issue.

  20. Exploring uncertainty in glacier mass balance modelling with Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    H. Machguth

    2008-12-01

    Full Text Available By means of Monte Carlo simulations we calculated uncertainty in modelled cumulative mass balance over 400 days at one particular point on the tongue of Morteratsch Glacier, Switzerland, using a glacier energy balance model of intermediate complexity. Before uncertainty assessment, the model was tuned to observed mass balance for the investigated time period and its robustness was tested by comparing observed and modelled mass balance over 11 years, yielding very small deviations. Both systematic and random uncertainties are assigned to twelve input parameters and their respective values estimated from the literature or from available meteorological data sets. The calculated overall uncertainty in the model output is dominated by systematic errors and amounts to 0.7 m w.e. or approximately 10% of total melt over the investigated time span. In order to provide a first order estimate on variability in uncertainty depending on the quality of input data, we conducted a further experiment, calculating overall uncertainty for different levels of uncertainty in measured global radiation and air temperature. Our results show that the output of a well calibrated model is subject to considerable uncertainties, in particular when applied for extrapolation in time and space where systematic errors are likely to be an important issue.

  1. The spatial and temporal variability of the surface mass balance in Antarctica: results from a regional climate model

    NARCIS (Netherlands)

    Lipzig, N.P.M. van; Meijgaard, E. van; Oerlemans, J.

    2002-01-01

    A 14 year integration with a regional atmospheric model (RACMO) is used to obtain detailed information on the Antarctic surface mass balance and to understand the mechanisms that are responsible for the spatial and temporal distribution of the surface mass balance. The model (Δx = 55 km) uses the pa

  2. The role of crystallization-driven exsolution on the sulfur mass balance in volcanic arc magmas

    Science.gov (United States)

    Su, Yanqing; Huber, Christian; Bachmann, Olivier; Zajacz, Zoltán; Wright, Heather M.; Vazquez, Jorge A.

    2016-01-01

    The release of large amounts of sulfur to the stratosphere during explosive eruptions affects the radiative balance in the atmosphere and consequentially impacts climate for up to several years after the event. Quantitative estimations of the processes that control the mass balance of sulfur between melt, crystals, and vapor bubbles is needed to better understand the potential sulfur yield of individual eruption events and the conditions that favor large sulfur outputs to the atmosphere. The processes that control sulfur partitioning in magmas are (1) exsolution of volatiles (dominantly H2O) during decompression (first boiling) and during isobaric crystallization (second boiling), (2) the crystallization and breakdown of sulfide or sulfate phases in the magma, and (3) the transport of sulfur-rich vapor (gas influx) from deeper unerupted regions of the magma reservoir. Vapor exsolution and the formation/breakdown of sulfur-rich phases can all be considered as closed-system processes where mass balance arguments are generally easier to constrain, whereas the contribution of sulfur by vapor transport (open system process) is more difficult to quantify. The ubiquitous “excess sulfur” problem, which refers to the much higher sulfur mass released during eruptions than what can be accounted for by amount of sulfur originally dissolved in erupted melt, as estimated from melt inclusion sulfur concentrations (the “petrologic estimate”), reflects the challenges in closing the sulfur mass balance between crystals, melt, and vapor before and during a volcanic eruption. In this work, we try to quantify the relative importance of closed- and open-system processes for silicic arc volcanoes using kinetic models of sulfur partitioning during exsolution. Our calculations show that crystallization-induced exsolution (second boiling) can generate a significant fraction of the excess sulfur observed in crystal-rich arc magmas. This result does not negate the important role of

  3. Simulation and reconstruction of parameters of streamflow and glacier mass balance in the Northern Caucasus

    Directory of Open Access Journals (Sweden)

    V. G. Konovalov

    2014-01-01

    Full Text Available The work was aimed at numerical modeling of spatial-temporal variability of the river Terek seasonal (April to September streamflow characteristics and long-term fluctuations of components of annual glacier mass balances in this basin and on the adjacent territories. Mass balance of glaciers Djankuat and Garabashi was calculated. Simulation was performed by means of stochastic modeling and discrete data presenting fields of main meteorological parameters (precipitation, air temperature and humidity having effect on the streamflow. Realization of this approach is complicated by the fact that spatial representativeness of hydrological and meteorological sites are not corresponding one to another. Data on the runoff is clearly related to the total drainage area closed by a gauging station. And for this data we study a relationship with meteorological parameters which are measured at a non-regular observational network whose spatial representativeness is unknown. These stations are generally located beyond the area under investigation (Fig. 2. Similar problem exists when we analyze a relationship between components of the mass balance of individual glaciers (Djankuat and Garabashi and the above climate characteristics measured at some stations located on the whole Caucasus territory. The same takes place when long-term indices of width and density of tree annual rings obtained in upper reaches of the river Kuban’ are used for analysis of variations of the runoff and the glacier mass balance in the river Terek basin located at a distance of 100-150 km from the Kuban’ dendrologic sites.To solve the problem we used a wide number of factors which directly (various information about the climate or indirectly (indices of the climate dryness, wood ring characteristics characterize conditions of formation of annual and seasonal river runoff and components of glacier mass balance in the North Caucasus. Use of all obtained information made possible the

  4. The role of crystallization-driven exsolution on the sulfur mass balance in volcanic arc magmas

    Science.gov (United States)

    Su, Y.; Huber, Christian; Bachmann, Olivier; Zajacz, Zoltán.; Wright, Heather; Vazquez, Jorge

    2016-08-01

    The release of large amounts of sulfur to the stratosphere during explosive eruptions affects the radiative balance in the atmosphere and consequentially impacts climate for up to several years after the event. Quantitative estimations of the processes that control the mass balance of sulfur between melt, crystals, and vapor bubbles is needed to better understand the potential sulfur yield of individual eruption events and the conditions that favor large sulfur outputs to the atmosphere. The processes that control sulfur partitioning in magmas are (1) exsolution of volatiles (dominantly H2O) during decompression (first boiling) and during isobaric crystallization (second boiling), (2) the crystallization and breakdown of sulfide or sulfate phases in the magma, and (3) the transport of sulfur-rich vapor (gas influx) from deeper unerupted regions of the magma reservoir. Vapor exsolution and the formation/breakdown of sulfur-rich phases can all be considered as closed-system processes where mass balance arguments are generally easier to constrain, whereas the contribution of sulfur by vapor transport (open system process) is more difficult to quantify. The ubiquitous "excess sulfur" problem, which refers to the much higher sulfur mass released during eruptions than what can be accounted for by amount of sulfur originally dissolved in erupted melt, as estimated from melt inclusion sulfur concentrations (the "petrologic estimate"), reflects the challenges in closing the sulfur mass balance between crystals, melt, and vapor before and during a volcanic eruption. In this work, we try to quantify the relative importance of closed- and open-system processes for silicic arc volcanoes using kinetic models of sulfur partitioning during exsolution. Our calculations show that crystallization-induced exsolution (second boiling) can generate a significant fraction of the excess sulfur observed in crystal-rich arc magmas. This result does not negate the important role of vapor

  5. Analysis of the mass balance time series of glaciers in the Italian Alps

    Science.gov (United States)

    Carturan, Luca; Baroni, Carlo; Brunetti, Michele; Carton, Alberto; Dalla Fontana, Giancarlo; Salvatore, Maria Cristina; Zanoner, Thomas; Zuecco, Giulia

    2016-03-01

    This work presents an analysis of the mass balance series of nine Italian glaciers, which were selected based on the length, continuity and reliability of observations. All glaciers experienced mass loss in the observation period, which is variable for the different glaciers and ranges between 10 and 47 years. The longest series display increasing mass loss rates, which were mainly due to increased ablation during longer and warmer ablation seasons. The mean annual mass balance (Ba) in the decade from 2004 to 2013 ranged from -1788 to -763 mm w.e. yr-1. Low-altitude glaciers with low range of elevation are more out of balance than the higher, larger and steeper glaciers, which maintain residual accumulation areas in their upper reaches. The response of glaciers is mainly controlled by the combination of October-May precipitations and June-September temperatures, but rapid geometric adjustments and atmospheric changes lead to modifications in their response to climatic variations. In particular, a decreasing correlation of Ba with the June-September temperatures and an increasing correlation with October-May precipitations are observed for some glaciers. In addition, the October-May temperatures tend to become significantly correlated with Ba, possibly indicating a decrease in the fraction of solid precipitation, and/or increased ablation, during the accumulation season. Because most of the monitored glaciers have no more accumulation area, their observations series are at risk due to their impending extinction, thus requiring a replacement soon.

  6. Estimation of Greenland's Ice Sheet Mass Balance Using ICESat and GRACE Data

    Science.gov (United States)

    Slobbe, D.; Ditmar, P.; Lindenbergh, R.

    2007-12-01

    Data of the GRACE gravity mission and the ICESat laser altimetry mission are used to create two independent estimates of Greenland's ice sheet mass balance over the full measurement period. For ICESat data, a processing strategy is developed using the elevation differences of geometrically overlapping footprints of both crossing and repeated tracks. The dataset is cleaned using quality flags defined by the GLAS science team. The cleaned dataset reveals some strong, spatially correlated signals that are shown to be related to physical phenomena. Different processing strategies are used to convert the observed temporal height differences to mass changes for 6 different drainage systems, further divided into a region above and below 2000 meter elevation. The results are compared with other altimetry based mass balance estimates. In general, the obtained results confirm trends discovered by others, but we also show that the choice of processing strategy strongly influences our results, especially for the areas below 2000 meter. Furthermore, GRACE based monthly variations of the Earth's gravity field as processed by CNES, CSR, GFZ and DEOS are used to estimate the mass balance change for North and South Greenland. It is shown that our results are comparable with recently published GRACE estimates (mascon solutions). On the other hand, the estimates based on GRACE data are only partly confirmed by the ICESat estimates. Possible explanations for the obvious differences will be discussed.

  7. 3D viscosity maps for Greenland and effect on GRACE mass balance estimates

    Science.gov (United States)

    van der Wal, Wouter; Xu, Zheng

    2016-04-01

    The GRACE satellite mission measures mass loss of the Greenland ice sheet. To correct for glacial isostatic adjustment numerical models are used. Although generally found to be a small signal, the full range of possible GIA models has not been explored yet. In particular, low viscosities due to a wet mantle and high temperatures due to the nearby Iceland hotspot could have a significant effect on GIA gravity rates. The goal of this study is to present a range of possible viscosity maps, and investigate the effect on GRACE mass balance estimates. Viscosity is derived using flow laws for olivine. Mantle temperature is computed from global seismology models, based on temperature derivatives for different mantle compositions. An indication for grain sizes is obtained by xenolith findings at a few locations. We also investigate the weakening effect of the presence of melt. To calculate gravity rates, we use a finite-element GIA model with the 3D viscosity maps and the ICE-5G loading history. GRACE mass balances for mascons in Greenland are derived with a least-squares inversion, using separate constraints for the inland and coastal areas in Greenland. Biases in the least-squares inversion are corrected using scale factors estimated from a simulation based on a surface mass balance model (Xu et al., submitted to The Cryosphere). Model results show enhanced gravity rates in the west and south of Greenland with 3D viscosity maps, compared to GIA models with 1D viscosity. The effect on regional mass balance is up to 5 Gt/year. Regional low viscosity can make present-day gravity rates sensitivity to ice thickness changes in the last decades. Therefore, an improved ice loading history for these time scales is needed.

  8. 20 years of mass balances on the Piloto glacier, Las Cuevas river basin, Mendoza, Argentina

    Science.gov (United States)

    Leiva, J. C.; Cabrera, G. A.; Lenzano, L. E.

    2007-10-01

    Climatic changes of the 20th century have altered the water cycle in the Andean basins of central Argentina. The most visible change is seen in the mountain glaciers, with loss of part of their mass due to decreasing thickness and a substantial recession in the last 100 years. This paper briefly describes the results of glacier mass balance research since 1979 in the Piloto Glacier at the Cajón del Rubio, in the headwaters of Las Cuevas River, presenting new results for the period 1997-2003. Very large interannual variability of net annual specific balance is evident, due largely to variations in winter snow accumulation, with a maximum net annual value of + 151 cm w.e. and a minimum value of - 230 cm w.e. Wet El Niño years are normally associated with positive net annual balances, while dry La Niña years generally result in negative balances. Within the 24-year period, 67% of the years show negative net annual specific balances, with a cumulative mass balance loss of - 10.50 m water equivalent (w.e.). Except for exceptions normally related to El Niño events, a general decreasing trend of winter snow accumulation is evident in the record, particularly after 1992, which has a strong effect in the overall negative mass balance values. The glacier contribution to Las Cuevas River runoff is analysed based on the Punta de Vacas River gauge station for a hypothetical year without snow precipitation (YWSP), when the snowmelt component is zero. Extremely dry years similar to a YWSP have occurred in 1968-1969, 1969-1970 and 1996-1997. The Punta de Vacas gauge station is located 62 km downstream from Piloto Glacier, and the basin contains 3.0% of uncovered glacier ice and 3.7% of debris-covered ice. The total glacier contribution to Las Cuevas River discharge is calculated as 82 ± 8% during extremely dry years. If glacier wastage continues at the present trend as observed during the last 2 decades, it will severely affect the water resources in the arid central Andes of

  9. Reconstructing glacier mass balances in the Central Andes of Chile and Argentina using local and regional hydro-climatic data

    Directory of Open Access Journals (Sweden)

    M. H. Masiokas

    2015-09-01

    Full Text Available Despite the great number and variety of glaciers in southern South America, in situ glacier mass balance records are extremely scarce and glacier–climate relationships are still poorly understood in this region. Here we use the longest (> 35 years and most complete in situ mass balance record, available for glaciar Echaurren Norte in the Andes at ~34° S, to develop a minimal glacier surface mass balance model that relies on nearby monthly precipitation and air temperature data as forcing. This basic model is able to explain 78 % of the variance in the annual glacier mass balance record over the 1978–2013 calibration period. An attribution assessment indicates that precipitation variability constitutes the most important forcing modulating annual glacier mass balances at this site. A regionally-averaged series of mean annual streamflow records from both sides of the Andes is then used to estimate, through simple linear regression, this glacier's annual mass balance variations since 1909. The reconstruction model captures 68 % of the observed glacier mass balance variability and shows three periods of sustained positive mass balances embedded in an overall negative trend totaling almost −42 m w.eq. over the past 105 years. The three periods of sustained positive mass balances (centered in the 1920s–1930s, in the 1980s and in the first decade of the 21st century coincide with several documented glacier advances in this region. Similar trends observed in other shorter glacier mass balance series suggest the glaciar Echaurren Norte reconstruction is representative of larger-scale conditions and could be useful for more detailed glaciological, hydrological and climatological assessments in this portion of the Andes.

  10. Twenty-one years of mass balance observations along the K-transect, West Greenland

    Directory of Open Access Journals (Sweden)

    R. S. W. van de Wal

    2012-08-01

    Full Text Available A 21-yr record is presented of surface mass balance measurements along the K-transect. The series covers the period 1990–2011. Data are available at eight sites along a transect over an altitude range of 380–1850 m at approximately 67° N in West Greenland. The surface mass balance gradient is on average 3.8 × 10−3 m w.e. m−1, and the mean equilibrium line altitude is 1553 m a.s.l. Only the lower three sites within 10 km of the margin up to an elevation of 700 m experience a significant increasing trend in the ablation over the entire period. Data are available at: doi:10.1594/PANGAEA.779181.

  11. Twenty-one years of mass balance observations along the K-transect, West Greenland

    Directory of Open Access Journals (Sweden)

    R. S. W. van de Wal

    2012-05-01

    Full Text Available A 21-yr record is presented of surface mass balance measurements along the K-transect. The series covers the period 1990–2011. Data are available at 8 sites along a transect over an altitude range of 390–1850 m at approximately 67° N in West Greenland. The surface mass balance gradient is on average 3.8 × 10−3 m w.e. m−1, and the mean equilibrium line altitude is 1553 m a.s.l. Only the lower 3 sites within 10 km of the margin experience a significant increasing trend in the ablation over the entire period. Data are available at: http://doi.pangaea.de/10.1594/PANGAEA.779181.

  12. Low-Level waste phase 1 melter testing off gas and mass balance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, C.N.

    1996-06-28

    Commercially available melter technologies were tested during 1994-95 as part of a multiphase program to test candidate technologies for vitrification of the low-level waste (LLW) stream to be derived from retrieval and pretreatment of Hanford Site tank wastes. Seven vendors were selected for Phase 1 testing to demonstrate vitrification of a high sodium content liquid LLW simulant. The tested melter technologies included four Joule-heated melters, a carbon electrode melter, a combustion melter, and a plasma melter. Various dry and slurry melter feed preparation processes were also tested. Various feed material samples, product glass samples, and process offgas streams were characterized to provide data for evaluation of process decontamination factors and material mass balances for each vitrification technology. This report describes the melter mass balance evaluations and results for six of the Phase 1 LLW melter vendor demonstration tests.

  13. Geometric changes and mass balance of the Austfonna ice cap, Svalbard

    Directory of Open Access Journals (Sweden)

    G. Moholdt

    2010-01-01

    Full Text Available The dynamics and mass balance regime of the Austfonna ice cap, the largest glacier on Svalbard, deviates significantly from most other glaciers in the region and is not fully understood. We have compared ICESat laser altimetry, airborne laser altimetry, GNSS surface profiles and radio echo-sounding data to estimate elevation change rates for the periods 1983–2007 and 2002–2008. The data sets indicate a pronounced interior thickening of up to 0.5 m y−1, at the same time as the margins are thinning at a rate of 1–3 m y−1. The southern basins are thickening at a higher rate than the northern basins due to a higher accumulation rate. The overall volume change in the 2002–2008 period is estimated to be −1.3±0.5 km3 w.e. y−1 (or −0.16±0.06 m w.e. y−1 where the entire net loss is due to a rapid retreat of the calving fronts. Since most of the marine ice loss occurs below sea level, Austfonna's current contribution to sea level change is close to zero. The geodetic results are compared to in-situ mass balance measurements which indicate that the 2004–2008 surface net mass balance has been slightly positive (0.05 m w.e. y−1 though with large annual variations. Similarities between local net mass balances and local elevation changes indicate that most of the ice cap is slow-moving and not in dynamic equilibrium with the current climate. More knowledge is needed about century-scale dynamic processes in order to predict the future evolution of Austfonna based on climate scenarios.

  14. Reconciling high-altitude precipitation in the upper Indus basin with glacier mass balances and runoff

    OpenAIRE

    Immerzeel, W. W.; N. Wanders; A. F. Lutz; J. M. Shea; M. F. P. Bierkens

    2015-01-01

    Mountain ranges in Asia are important water suppliers, especially if downstream climates are arid, water demands are high and glaciers are abundant. In such basins, the hydrological cycle depends heavily on high-altitude precipitation. Yet direct observations of high-altitude precipitation are lacking and satellite derived products are of insufficient resolution and quality to capture spatial variation and magnitude of mountain precipitation. Here we use glacier mass balances t...

  15. Contributions of GPS occultations to Antarctica ice sheet mass balance studies

    OpenAIRE

    S. J. Ge; Shum, C.K.; Jens Wickert

    2002-01-01

    Antarctica is the coldest, stormiest and the most remote continent on Earth. Nearly 75% of the world's fresh water is trapped in the Antarctic ice sheets, which could significantly raise the global sea level if the ice sheets would melt. The continental ice sheet mass balance budget remains one of the largest uncertainties in the understanding of the causes of global sea level rise. Advanced gravity mapping satellite missions, such as CHAMP, GRACE and GOCE, are anticipated to provide signi...

  16. Slow Pyrolysis vs Gasification :mass and energy balances using a predictive model

    OpenAIRE

    Jung, Céline Gisèle; Fontana, André

    2007-01-01

    When the recovery of mixed plastics is not economically viable, the main issue today is land filling or incineration. The present study shows the opportunities in producing gaseous or liquid substitution fuels by pyrolysis or gasification. By both processes, the issued fuels characteristics are quite different so that the application fields have to be optimized. If plastics are mixed with other waste, sorting could be too expensive. Using our predictive model, pyrolysis mass balance could be ...

  17. Base flow separation: A comparison of analytical and mass balance methods

    Science.gov (United States)

    Lott, Darline A.; Stewart, Mark T.

    2016-04-01

    Base flow is the ground water contribution to stream flow. Many activities, such as water resource management, calibrating hydrological and climate models, and studies of basin hydrology, require good estimates of base flow. The base flow component of stream flow is usually determined by separating a stream hydrograph into two components, base flow and runoff. Analytical methods, mathematical functions or algorithms used to calculate base flow directly from discharge, are the most widely used base flow separation methods and are often used without calibration to basin or gage-specific parameters other than basin area. In this study, six analytical methods are compared to a mass balance method, the conductivity mass-balance (CMB) method. The base flow index (BFI) values for 35 stream gages are obtained from each of the seven methods with each gage having at least two consecutive years of specific conductance data and 30 years of continuous discharge data. BFI is cumulative base flow divided by cumulative total discharge over the period of record of analysis. The BFI value is dimensionless, and always varies from 0 to 1. Areas of basins used in this study range from 27 km2 to 68,117 km2. BFI was first determined for the uncalibrated analytical methods. The parameters of each analytical method were then calibrated to produce BFI values as close to the CMB derived BFI values as possible. One of the methods, the power function (aQb + cQ) method, is inherently calibrated and was not recalibrated. The uncalibrated analytical methods have an average correlation coefficient of 0.43 when compared to CMB-derived values, and an average correlation coefficient of 0.93 when calibrated with the CMB method. Once calibrated, the analytical methods can closely reproduce the base flow values of a mass balance method. Therefore, it is recommended that analytical methods be calibrated against tracer or mass balance methods.

  18. Materials, Capital, Direct/Indirect Substitution and Mass Balance Production Functions

    OpenAIRE

    Bergh, van den, H.

    1998-01-01

    A foundation is provided for a correct and accurate analysis of the relationship between monetary values and physical dimensions in economic production. A distinction is proposed between direct and indirect substitution. Linked to this, a classification is offered of various types of substitutability and complementarity relationships between production factors. It is argued that the neoclassical production function may be consistent with mass balance, but is unsuitable for a detailed and accu...

  19. Quantification of colloidal and aqueous element transfer in soils: The dual-phase mass balance model

    Science.gov (United States)

    Bern, Carleton R.; Thompson, Aaron; Chadwick, Oliver A.

    2015-01-01

    Mass balance models have become standard tools for characterizing element gains and losses and volumetric change during weathering and soil development. However, they rely on the assumption of complete immobility for an index element such as Ti or Zr. Here we describe a dual-phase mass balance model that eliminates the need for an assumption of immobility and in the process quantifies the contribution of aqueous versus colloidal element transfer. In the model, the high field strength elements Ti and Zr are assumed to be mobile only as suspended solids (colloids) and can therefore be used to distinguish elemental redistribution via colloids from redistribution via dissolved aqueous solutes. Calculations are based upon element concentrations in soil, parent material, and colloids dispersed from soil in the laboratory. We illustrate the utility of this model using a catena in South Africa. Traditional mass balance models systematically distort elemental gains and losses and changes in soil volume in this catena due to significant redistribution of Zr-bearing colloids. Applying the dual-phase model accounts for this colloidal redistribution and we find that the process accounts for a substantial portion of the major element (e.g., Al, Fe and Si) loss from eluvial soil. In addition, we find that in illuvial soils along this catena, gains of colloidal material significantly offset aqueous elemental loss. In other settings, processes such as accumulation of exogenous dust can mimic the geochemical effects of colloid redistribution and we suggest strategies for distinguishing between the two. The movement of clays and colloidal material is a major process in weathering and pedogenesis; the mass balance model presented here is a tool for quantifying effects of that process over time scales of soil development.

  20. Estimating the avalanche contribution to the mass balance of debris covered glaciers

    OpenAIRE

    Banerjee, A.; Shankar, R.

    2014-01-01

    Avalanche from high head walls dominates the net accumulation in many debris covered glaciers in the Himalaya. These avalanche contributions are difficult to directly measure and may cause a systematic bias in glaciological mass balance measurements. In this paper we develop a method to estimate the avalanche contribution using available data, within the context of an idealised flowline model of the glacier. We focus on Hamtah glacier in Western Himalaya ...

  1. Chloride-mass-balance for predicting increased recharge after land-use change

    OpenAIRE

    Gee, G.W.; Z. F. Zhang; Tyler, S.W.; Albright, W.H.; Singleton, M.J.

    2004-01-01

    The chloride-mass-balance (CMB) method has been used extensively to estimate recharge in arid and semi-arid environments. Required data include estimates of annual precipitation, total chloride input (from dry fallout and precipitation), and pore-water chloride concentrations. Typically, CMB has been used to estimate ancient recharge but recharge from recent land-use change has also been documented. Recharge rates below a few mm/yr are reliably detected with CMB; however, estimates above...

  2. Linking glacier annual mass balance and glacier albedo retrieved from MODIS data

    OpenAIRE

    Dumont, M; Gardelle, J.; P. Sirguey; A. Guillot; Six, D.; Rabatel, A.; Y. Arnaud

    2012-01-01

    Albedo is one of the variables controlling the mass balance of temperate glaciers. Multispectral imagers, such as MODerate Imaging Spectroradiometer (MODIS) on board the TERRA and AQUA satellites, provide a means to monitor glacier surface albedo. In this study, different methods to retrieve broadband glacier surface albedo from MODIS data are compared. The effect of multiple reflections due to the rugged topography and of the anisotropic reflection of snow and ...

  3. Material-mass Balance of Smallholder Oil Palm Processing in the Niger Delta, Nigeria

    OpenAIRE

    Elijah I. Ohimain; Sylvester C. Izah; Francis A.U. Obieze

    2013-01-01

    This study evaluates the material-mass balance of smallholder oil palm processing in Niger Delta Nigeria. Ten smallholder oil palm processing mills were randomly sampled. Measuring scale was used to measure the weight of the Fresh Fruit Bunch (FFB) and all the processing intermediates/products including Threshed Fresh Fruit (TFF), Palm Pressed Fibre (PPF), Palm Kernel Shell (PKS), Empty Fruit Bunch (EFB), Crude Palm Oil (CPO), chaff and nut. During the study period (13-22 April 2012), 8 of th...

  4. A mass balance study of the phytoremediation of perchloroethylene-contaminated groundwater

    OpenAIRE

    James, C Andrew; Xin, Gang; Doty, Sharon L.; Muiznieks, Indulis; Newman, Lee; Strand, Stuart E

    2009-01-01

    A mass balance study was performed under controlled field conditions to investigate the phytoremediation of perchloroethylene (PCE) by hybrid poplar trees. Water containing 7–14 mg L−1 PCE was added to the test bed. Perchloroethylene, trichloroethylene, and cis-dichloroethylene were detected in the effluent at an average of 0.12 mg L−1, 3.9 mg L−1, and 1.9 mg L−1, respectively. The total mass of chlorinated ethenes in the water was reduced by 99%. Over 95% of the recovered chlorine was as fre...

  5. Long term mass balance of the Helheim and Kangerdlugssuaq glaciers in

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Fitzner, Antje; Kjær, Kurt;

    2013-01-01

    Observations over the past decade show huge ice loss associated with speeding up of glaciers in southeast Greenland in 2003, followed by a deceleration in 2006. These short-term episodic dynamic perturbations have a major impact on the mass balance at decadal scale. However, to improve the projec......Observations over the past decade show huge ice loss associated with speeding up of glaciers in southeast Greenland in 2003, followed by a deceleration in 2006. These short-term episodic dynamic perturbations have a major impact on the mass balance at decadal scale. However, to improve...... the projection of future sea level rise, a long-term data record that reveals the mass balance between episodic events is required. Here, we extend the observational record of marginal thinning of Helheim glacier (HG) and Kangerdlugssuaq glacier (KG) from 7 to 30 years. Our measurements reveal that, although...... in air temperature suggest that both outlet glaciers respond immediately to small fluctuations in both the SST and air temperature. Furthermore, we compare our observations of ice flow speed and elevation changes with predictions based on the The Parallel Ice Sheet Model (PISM) software....

  6. A Range Correction for Icesat and Its Potential Impact on Ice-sheet Mass Balance Studies

    Science.gov (United States)

    Borsa, A. A.; Moholdt, G.; Fricker, H. A.; Brunt, Kelly M.

    2014-01-01

    We report on a previously undocumented range error in NASA's Ice, Cloud and land Elevation Satellite (ICESat) that degrades elevation precision and introduces a small but significant elevation trend over the ICESat mission period. This range error (the Gaussian-Centroid or 'G-C'offset) varies on a shot-to-shot basis and exhibits increasing scatter when laser transmit energies fall below 20 mJ. Although the G-C offset is uncorrelated over periods less than1 day, it evolves over the life of each of ICESat's three lasers in a series of ramps and jumps that give rise to spurious elevation trends of -0.92 to -1.90 cm yr(exp -1), depending on the time period considered. Using ICESat data over the Ross and Filchner-Ronne ice shelves we show that (1) the G-C offset introduces significant biases in ice-shelf mass balance estimates, and (2) the mass balance bias can vary between regions because of different temporal samplings of ICESat.We can reproduce the effect of the G-C offset over these two ice shelves by fitting trends to sample-weighted mean G-C offsets for each campaign, suggesting that it may not be necessary to fully repeat earlier ICESat studies to determine the impact of the G-C offset on ice-sheet mass balance estimates.

  7. Mass Balance of Perfluorinated Alkyl Acids in a Pristine Boreal Catchment.

    Science.gov (United States)

    Filipovic, Marko; Laudon, Hjalmar; McLachlan, Michael S; Berger, Urs

    2015-10-20

    Mass balances of ten individual perfluorinated alkyl acids (PFAAs) in two nested pristine catchments in Northern Sweden with different sizes and hydrological functions were assembled for 2011-2012. Concentrations of PFAAs in rain and snowmelt, as well as in streamwater at the outlet of the two watersheds were measured and used to calculate PFAA atmospheric inputs to and riverine outputs from the catchments. The results generally showed a great excess of PFAA inputs for both catchments over the whole study year. However, during the spring flood period, the inputs and outputs were within a factor of 2 for several PFAAs and the streamwater showed PFAA patterns resembling the patterns in rain (as opposed to snowmelt), suggesting that snowmelt water infiltrating the ground had displaced water from the previous summer. Comparison of PFAA mass balances between the two catchments further suggested that atmospheric inputs of short-chain (replacement) perfluoroalkyl carboxylic acids had increased in the years before sampling, while inputs of the legacy perfluorooctane sulfonic acid had decreased. Overall, the mass balances indicate that a considerable portion of the PFAAs deposited from the atmosphere are stored in soil and may be released to surface and marine water environments in the future. PMID:26390224

  8. The footprint of Asian monsoon dynamics in the mass and energy balance of a Tibetan glacier

    Directory of Open Access Journals (Sweden)

    T. Mölg

    2012-08-01

    Full Text Available Determinations of glacier-wide mass and energy balance are still scarce for the remote mountains of the Tibetan Plateau, where field measurements are challenging. Here we run and evaluate a physical, distributed mass balance model for Zhadang glacier (central Tibet, 30° N, based on in-situ measurements over 2009–2011 and an uncertainty estimate by Monte Carlo and ensemble strategies. The model application aims to provide the first quantification of how the Indian Summer Monsoon (ISM impacts an entire glacier over the various stages of the monsoon's annual cycle. We find a strong and systematic ISM footprint on the interannual scale. Early (late monsoon onset causes higher (lower accumulation, and reduces (increases the available energy for ablation primarily through changes in absorbed shortwave radiation. By contrast, only a weak footprint exists in the ISM cessation phase. Most striking though is the core monsoon season: local mass and energy balance variability is fully decoupled from the active/break cycle that defines large-scale atmospheric variability during the ISM. Our results demonstrate quantitatively that monsoon onset strongly affects the ablation season of glaciers in Tibet. However, we find no direct ISM impact on the glacier in the main monsoon season, which has not been acknowledged so far. This result also adds cryospheric evidence that regional modification of the large-scale monsoon flow prevails on the Tibetan Plateau in summer.

  9. Relative appendicular skeletal muscle mass is associated with isokinetic muscle strength and balance in healthy collegiate men.

    Science.gov (United States)

    Kim, Sung-Eun; Hong, Ju; Cha, Jun-Youl; Park, Jung-Min; Eun, Denny; Yoo, Jaehyun; Jee, Yong-Seok

    2016-11-01

    There are few studies on the relationship between skeletal muscle mass and balance in the young ages. We investigated the relationship between appendicular skeletal muscle mass, isokinetic muscle strength of lower extremity, and balance among healthy young men using relative skeletal muscle index. Thirty men were grouped according to relative appendicular skeletal muscle mass index: higher skeletal muscle group (n = 15) and lower skeletal muscle group (n = 15). Static and dynamic balance abilities were measured using the following: a test where participants stood on one leg with eyes closed, a modified Clinical Test of Sensory Interaction on Balance (mCTSIB) with eyes open and eyes closed, a stability test, and limits of stability test. The muscle strength of lower extremities was measured with an isokinetic analyser in hip, knee, and ankle joints. Participants with higher appendicular skeletal muscle mass were significantly more stable in maintaining dynamic balance than those with lower appendicular skeletal muscle mass. Moreover, appendicular skeletal muscle mass index was positively correlated with dynamic balance ability. Participants with higher appendicular skeletal muscle mass had stronger strength in the lower extremity, and there were significant differences in the isokinetic torque ratios between groups. From these results, it can be inferred that higher appendicular skeletal muscle mass relates to muscle strength and the alteration in the peak torque ratio of the lower extremity, contributing to the maintenance of balance.

  10. 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.

  11. Region-wide glacier mass balances over the Pamir-Karakoram-Himalaya during 1999–2011

    Directory of Open Access Journals (Sweden)

    J. Gardelle

    2013-03-01

    Full Text Available The recent evolution of Pamir-Karakoram-Himalaya (PKH glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To overcome the lack of region-wide mass balance data, we compared the 2000 Shuttle Radar Topography Mission (SRTM digital elevation model (DEM to recent (2008–2011 DEMs derived from SPOT5 stereo-imagery for 8 sites spread from Pamir to eastern Himalaya. The region-wide glacier mass balances were contrasted during the last decade, with moderate mass losses in eastern and central Himalaya (−0.21 ± 0.10 m yr−1 w.e. to −0.29 ± 0.09 m yr−1 w.e. and larger losses in western Himalaya (−0.41 ± 0.11 m yr−1 w.e.. Recently reported slight mass gain of glaciers in central Karakoram is confirmed for a larger area (+0.10 ± 0.19 m yr−1 w.e. and, new, also observed for glaciers in western Pamir (+0.14 ± 0.10 m yr−1 w.e.. We propose that the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers is estimated at −0.12 ± 0.06 m yr−1 w.e. In contrast to Indus, the relative glacier imbalance contribution to Brahmaputra and Ganges discharges is higher than previously modeled glacier seasonal contribution.

  12. North Cascade Glacier Annual Mass Balance Record Analysis 1984-2013

    Science.gov (United States)

    Pelto, M. S.

    2014-12-01

    The North Cascade Glacier Climate Project (NCGCP) was founded in 1983 to monitor 10 glaciers throughout the range and identify their response to climate change. The annual observations include mass balance, terminus behavior, glacier surface area and accumulation area ratio (AAR). Annual mass balance (Ba) measurements have been continued on the 8 original glaciers that still exist. Two glaciers have disappeared: the Lewis Glacier and Spider Glacier. In 1990, Easton Glacier and Sholes Glacier were added to the annual balance program to offset the loss. One other glacier Foss Glacier has declined to the extent that continued measurement will likely not be possible. Here we examine the 30 year long Ba time series from this project. All of the data have been reported to the World Glacier Monitoring Service (WGMS). This comparatively long record from glaciers in one region conducted by the same research program using the same methods offers some useful comparative data. Degree day factors for melt of 4.3 mm w.e.°C-1d-1 for snow and 6.6 mm w.e.°C-1d-1 for ice has been determined from 412 days of ablation observation. The variation in the AAR for equilibrium Ba is small ranging from 60 to 67. The mean annual balance of the glaciers from 1984-2013 is -0.45 ma-1, ranging from -0.31 to -0.57 ma-1 for individual glacier's. The correlation coefficient of Ba is above 0.80 between all glaciers including the USGS benchmark glacier, South Cascade Glacier. This indicates that the response is to regional climate change, not local factors. The mean annual balance of -0.45 ma-1 is close to the WGMS global average for this period -0.50 ma-1. The cumulative loss of 13.5 m w.e. and 15 m of ice thickness represents more than 20% of the volume of the glaciers.

  13. Glacier albedo decrease in the European Alps: potential causes and links with mass balances

    Science.gov (United States)

    Di Mauro, Biagio; Julitta, Tommaso; Colombo, Roberto

    2016-04-01

    Both mountain glaciers and polar ice sheets are losing mass all over the Earth. They are highly sensitive to climate variation, and the widespread reduction of glaciers has been ascribed to the atmospheric temperature increase. Beside this driver, also ice albedo plays a fundamental role in defining mass balance of glaciers. In fact, dark ice absorbs more energy causing faster glacier melting, and this can drive to more negative balances. Previous studies showed that the albedo of Himalayan glaciers and the Greenland Ice Sheet is decreasing with important rates. In this contribution, we tested the hypothesis that also glaciers in the European Alps are getting darker. We analyzed 16-year time series of MODIS (MODerate resolution Imaging Spectrometer) snow albedo from Terra (MOD13A1, 2000-2015) and Aqua (MYD13A1, 2002-2015) satellites. These data feature a spatial resolution of 500m and a daily temporal resolution. We evaluated the existence of a negative linear and nonlinear trend of the summer albedo values both at pixel and at glacier level. We also calculated the correlation between MODIS summer albedo and glacier mass balances (from the World Glaciological Monitoring Service, WGMS database), for all the glaciers with available mass balance during the considered period. In order to estimate the percentage of the summer albedo that can be explained by atmospheric temperature, we correlated MODIS albedo and monthly air temperature extracted from the ERA-Interim reanalysis dataset. Results show that decreasing trends exist with a strong spatial variability in the whole Alpine chain. In large glaciers, such as the Aletch (Swiss Alps), the trend varies significantly also within the glacier, showing that the trend is higher in the area across the accumulation and ablation zone. Over the 17 glaciers with mass balance available in the WGMS data set, 11 gave significant relationship with the MODIS summer albedo. Moreover, the comparison between ERA-Interim temperature

  14. Quantification of Submarine Groundwater Discharge Using a Radon (222-Rn) Mass Balance and Hydrogeological Modelling

    Science.gov (United States)

    Petermann, Eric; Stollberg, Reiner; Scholten, Jan; Knöller, Kay; Schubert, Michael

    2016-04-01

    Apart from river and surface water runoff subsurface discharge of groundwater plays a key role in coastal water and matter budgets. Two major forms of submarine groundwater discharge (SGD) can be distinguished: (i) pure freshwater discharge from continental aquifers that are connected to the coastal sea driven by a positive hydraulic gradient (fresh SGD) and (ii) re-circulation of seawater that has penetrated permeable coastal sediments (re-circulated SGD), e.g. driven by tidal pumping. The localization of SGD zones and the quantification of SGD fluxes is of high interest for coastal water management due to potential threats related to SGD, namely (i) the detrimental impact of discharging nutrient- or contaminant-laden groundwater on coastal seawater quality, an aspect that is of relevance along coastlines which are impacted by agriculture, industry or intense urbanization, and (ii) the loss of freshwater to the ocean, an issue that is of major relevance in all coastal areas with (seasonally) limited freshwater availability. In this work, we discuss estimates for the total (fresh + re-circulated) SGD fluxes derived from a mass balance of the radioactive noble gas radon (222-Rn) with estimates of fresh SGD fluxes derived by hydrogeological modelling. The precision of the mass balance results depends on the adequate determination of the mass balance source and sink terms. These terms are calculated based on field observations of environmental tracers (salinity, δ18O, 222-Rn, 223-Ra, 224-Ra, 226-Ra) in seawater and porewater, as well as on meteorological data. The numerical hydrogeological model estimates groundwater flow based on groundwater monitoring data, river flow data, groundwater recharge estimates, tidal dynamics, and density effects along the freshwater/seawater interface. We compare these two independent methodological approaches of SGD flux estimation, discuss results regarding their relevance for the regional water balance and reason the implications of

  15. The mid-cretaceous water bearer: Isotope mass balance quantification of the Albian hydrologic cycle

    Science.gov (United States)

    Ufnar, David F.; Gonzalez, Luis A.; Ludvigson, Greg A.; Brenner, Richard L.; Witzke, B.J.

    2002-01-01

    A latitudinal gradient in meteoric ??18O compositions compiled from paleosol sphaerosiderites throughout the Cretaceous Western Interior Basin (KWIB) (34-75??N paleolatitude) exhibits a steeper, more depleted trend than modern (predicted) values (3.0??? [34??N latitude] to 9.7??? [75??N] lighter). Furthermore, the sphaerosiderite meteoric ??18O latitudinal gradient is significantly steeper and more depleted (5.8??? [34??N] to 13.8??? [75??N] lighter) than a predicted gradient for the warm mid-Cretaceous using modern empirical temperature-??18O precipitation relationships. We have suggested that the steeper and more depleted (relative to the modern theoretical gradient) meteoric sphaerosiderite ??18O latitudinal gradient resulted from increased air mass rainout effects in coastal areas of the KWIB during the mid-Cretaceous. The sphaerosiderite isotopic data have been used to constrain a mass balance model of the hydrologic cycle in the northern hemisphere and to quantify precipitation rates of the equable 'greenhouse' Albian Stage in the KWIB. The mass balance model tracks the evolving isotopic composition of an air mass and its precipitation, and is driven by latitudinal temperature gradients. Our simulations indicate that significant increases in Albian precipitation (34-52%) and evaporation fluxes (76-96%) are required to reproduce the difference between modern and Albian meteoric siderite ??18O latitudinal gradients. Calculations of precipitation rates from model outputs suggest mid-high latitude precipitation rates greatly exceeded modern rates (156-220% greater in mid latitudes [2600-3300 mm/yr], 99% greater at high latitudes [550 mm/yr]). The calculated precipitation rates are significantly different from the precipitation rates predicted by some recent general circulation models (GCMs) for the warm Cretaceous, particularly in the mid to high latitudes. Our mass balance model by no means replaces GCMs. However, it is a simple and effective means of obtaining

  16. Active tuned mass damper in vehicles. Integrated mass and energy balance; Mechatronische Schwingungstilger in Fahrzeugen. Ganzheitliche Massen- und Energiebilanz

    Energy Technology Data Exchange (ETDEWEB)

    Granzow, Sebastian

    2012-04-02

    The number of mechatronic automotive applications is growing rapidly and becoming more and more important. On the other hand, the automotive industry is faced with the ambitious challenge to significantly reduce CO{sub 2}-emissions. The vehicle mass is as a part of the driving resistance is a starting point. New innovative approaches are required for lightweight constructions. Taking the two aspects together, this leads inevitably to the question: Is it possible to support automotive lightweight construction by using mechatronic systems? The Mechatronic vibration absorber is a combination of a mechanical oscillating system with an electronically controllable force component. This allows a broadband and situation-dependent influence of vehicle vibration behavior. Mechatronic vibration absorbers are suitable to compensate a loss of riding comfort due to a reduction of the body mass. Essential for this is a multidisciplinary simulation environment. The mechatronic vibration absorber, including appropriate control systems, the nonlinear chassis and the elastic body characteristics, inclusive of mutual interactions are mapped in the simulation environment Matlab. In addition to the representation of the oscillating vehicle the determination of the total energy requirements is necessary. To achieve a CO{sub 2}-reduction target, the overall energy balance of lightweight and the electrical vibration absorber energy, which is offered by the vehicle, is required. The question of the real vibration absorber energy needs to be discussed in the context of the individual driving behavior. Ultimately, the overall energy balance is inherently dependent of the individual driving behavior.

  17. Reconciling high-altitude precipitation in the upper Indus basin with glacier mass balances and runoff

    Science.gov (United States)

    Immerzeel, Walter; Wanders, Niko; Lutz, Arthur; Shea, Joseph; Bierkens, Marc

    2016-04-01

    Mountain ranges in Asia are important water suppliers, especially if downstream climates are arid, water demands are high and glaciers are abundant. In such basins, the hydrological cycle depends heavily on high-altitude precipitation. Yet direct observations of high-altitude precipitation are lacking and satellite derived products are of insufficient resolution and quality to capture spatial variation and magnitude of mountain precipitation. Here we use glacier mass balances to inversely infer the high-altitude precipitation in the upper Indus basin and show that the amount of precipitation required to sustain the observed mass balances of large glacier systems is far beyond what is observed at valley stations or estimated by gridded precipitation products. An independent validation with observed river flow confirms that the water balance can indeed only be closed when the high altitude precipitation on average is more than twice as high and in extreme cases up to a factor of 10 higher than previously thought. We conclude that these findings alter the present understanding of high-altitude hydrology and will have an important bearing on climate change impact studies, planning and design of hydropower plants and irrigation reservoirs as well as the regional geopolitical situation in general.

  18. Antarctic Ice-Sheet Mass Balance from Satellite Altimetry 1992 to 2001

    Science.gov (United States)

    Zwally, H. Jay; Brenner, Anita C.; Cornejo, Helen; Giovinetto, Mario; Saba, Jack L.; Yi, Donghui

    2003-01-01

    A major uncertainty in understanding the causes of the current rate of sea level rise is the potential contributions from mass imbalances of the Greenland and Antarctic ice sheets. Estimates of the current mass balance of the Antarctic ice sheet are derived from surface- elevation changes obtained from 9 years of ERS - 1 & 2 radar altimeter data. Elevation time-series are created from altimeter crossovers among 90-day data periods on a 50 km grid to 81.5 S. The time series are fit with a multivariate linear/sinusoidal function to give the average rate of elevation change (dH/dt). On the major Rome-Filchner, Ross, and Amery ice shelves, the W d t are small or near zero. In contrast, the ice shelves of the Antarctic Peninsula and along the West Antarctic coast appear to be thinning significantly, with a 23 +/- 3 cm per year surface elevation decrease on the Larsen ice shelf and a 65 +/- 4 cm per year decrease on the Dotson ice shelf. On the grounded ice, significant elevation decreases are obtained over most of the drainage basins of the Pine Island and Thwaites glaciers in West Antarctica and inland of Law Dome in East Antarctica. Significant elevation increases are observed within about 200 km of the coast around much of the rest of the ice sheet. Farther inland, the changes are a mixed pattern of increases and decreases with increases of a few centimeters per year at the highest elevations of the East Antarctic plateau. The derived elevation changes are combined with estimates of the bedrock uplift from several models to provide maps of ice thickness change. The ice thickness changes enable estimates of the ice mass balances for the major drainage basins, the overall mass balance, and the current contribution of the ice sheet to global sea level change.

  19. Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Siyu; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Huang, J.; Huang, Zhongwei; Bi, Jianrong; Zhang, Wu; Shi, Jinsen; Yang, Lei; Li, Deshuai; Li, Jinxin

    2014-12-01

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust mass balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.

  20. Mass balance of Mars' residual south polar cap from CTX images and other data

    Science.gov (United States)

    Thomas, P. C.; Calvin, W.; Cantor, B.; Haberle, R.; James, P. B.; Lee, S. W.

    2016-04-01

    Erosion of pits in the residual south polar cap (RSPC) of Mars concurrent with deposition and fluctuating cap boundaries raises questions about the mass balance and long term stability of the cap. Determining a mass balance by measurement of a net gain or loss of atmospheric CO2 by direct pressure measurements (Haberle, R.M. et al. [2014]. Secular climate change on Mars: An update using one Mars year of MSL pressure data. American Geophysical Union (Fall). Abstract 3947), although perhaps the most direct method, has so far given ambiguous results. Estimating volume changes from imaging data faces challenges, and has previously been attempted only in isolated areas of the cap. In this study we use 6 m/pixel Context Imager (CTX) data from Mars year 31 to map all the morphologic units of the RSPC, expand the measurement record of pit erosion rates, and use high resolution images to place limits on vertical changes in the surface of the residual cap. We find the mass balance in Mars years 9-31 to be -6 to +4 km3/♂y, or roughly -0.039% to +0.026% of the mean atmospheric CO2 mass/♂y. The indeterminate sign results chiefly from uncertainty in the amounts of deposition or erosion on the upper surfaces of deposits (as opposed to scarp retreat). Erosion and net deposition in this period appear to be controlled by summertime planetary scale dust events, the largest occurring in MY 9, another, smaller one in MY 28. The rates of erosion and the deposition observed since MY 9 appear to be consistent with the types of deposits and erosional behavior found in most of the residual cap. However, small areas (deposits may require extended periods (>100 ♂y) of depositional and/or erosional conditions different from those occurring in the period since MY 9, although these environmental differences could be subtle.

  1. Energy and mass balance in the three-phase interstellar medium

    Science.gov (United States)

    Wang, Zhong; Cowie, Lennox L.

    1988-01-01

    Details of the energy and mass balances are considered in the context of a three-phase interstellar medium. The rates of mass exchange between the different phases are derived based on the pressure variations created by supernova remnant expansions. It is shown that the pressure-confined warm and cold gases have stable temperatures under a variety of interstellar conditions. The three-phase quasi-static configuration is found to be a natural outcome, and both warm and cold phases generally contribute about half of the total mass density to the diffuse interstellar gas. The model is also likely to be self-regulatory in the sense that variations of the input parameters do not strongly alter the general result, which is consistent with most current observations. The consequences of extreme conditions on this model are considered, and the possible implications for interstellar medium in other galaxies are briefly discussed.

  2. Mass Balance of the West Antarctic Ice-Sheet from ICESat Measurements

    Science.gov (United States)

    Zwally, H. Jay; Li, Jun; Robins, John; Saba, Jack L.; Yi, Donghui

    2011-01-01

    Mass balance estimates for 2003-2008 are derived from ICESat laser altimetry and compared with estimates for 1992-2002 derived from ERS radar altimetry. The net mass balance of 3 drainage systems (Pine Island, Thwaites/Smith, and the coast of Marie Bryd) for 2003-2008 is a loss of 100 Gt/yr, which increased from a loss of 70 Gt/yr for the earlier period. The DS including the Bindschadler and MacAyeal ice streams draining into the Ross Ice Shelf has a mass gain of 11 Gt/yr for 2003-2008, compared to an earlier loss of 70 Gt/yr. The DS including the Whillans and Kamb ice streams has a mass gain of 12 Gt/yr, including a significant thickening on the upper part of the Kamb DS, compared to a earlier gain of 6 Gt/yr (includes interpolation for a large portion of the DS). The other two DS discharging into the Ronne Ice Shelf and the northern Ellsworth Coast have a mass gain of 39 Gt/yr, compared to a gain of 4 Gt/yr for the earlier period. Overall, the increased losses of 30 Gt/yr in the Pine Island, Thwaites/Smith, and the coast of Marie Bryd DSs are exceeded by increased gains of 59 Gt/yr in the other 4 DS. Overall, the mass loss from the West Antarctic ice sheet has decreased to 38 Gt/yr from the earlier loss of 67 Gt/yr, reducing the contribution to sea level rise to 0.11 mm/yr from 0.19 mm/yr

  3. Uncertainty in modeling dust mass balance and radiative forcing from size parameterization

    Directory of Open Access Journals (Sweden)

    C. Zhao

    2013-07-01

    Full Text Available This study examines the uncertainties in simulating mass balance and radiative forcing of mineral dust due to biases in the dust size parameterization. Simulations are conducted quasi-globally (180° W–180° E and 60° S–70° N using the WRF-Chem model with three different approaches to represent dust size distribution (8-bin, 4-bin, and 3-mode. The biases in the 3-mode or 4-bin approaches against a relatively more accurate 8-bin approach in simulating dust mass balance and radiative forcing are identified. Compared to the 8-bin approach, the 4-bin approach simulates similar but coarser size distributions of dust particles in the atmosphere, while the 3-mode approach retains more fine dust particles but fewer coarse dust particles due to its prescribed σg of each mode. Although the 3-mode approach yields up to 10 days longer dust mass lifetime over the remote oceanic regions than the 8-bin approach, the three size approaches produce similar dust mass lifetime (3.2 days to 3.5 days on quasi-global average, reflecting that the global dust mass lifetime is mainly determined by the dust mass lifetime near the dust source regions. With the same global dust emission (∼6000 Tg yr-1, the 8-bin approach produces a dust mass loading of 39 Tg, while the 4-bin and 3-mode approaches produce 3% (40.2 Tg and 25% (49.1 Tg higher dust mass loading, respectively. The difference in dust mass loading between the 8-bin approach and the 4-bin or 3-mode approaches has large spatial variations, with generally smaller relative difference (-2 and atmospheric warming (0.39∼0.96 W m-2 and in a tremendous difference of a factor of ∼10 in dust TOA cooling (-0.24∼-2.20 W m-2. An uncertainty of a factor of 2 is quantified in dust emission estimation due to the different size parameterizations. This study also highlights the uncertainties in modeling dust mass and number loading, deposition fluxes, and radiative forcing resulting from different size

  4. The equilibrium flow and mass balance of the Taku Glacier, Alaska 1950–2006

    Directory of Open Access Journals (Sweden)

    K. F. Sprenke

    2008-05-01

    Full Text Available The Taku Glacier, Alaska has advanced 7.5 km since the late nineteenth century, while all other primary outlet glaciers of the Juneau Icefield are in retreat. The Juneau Icefield Research Program has completed field work on the Taku Glacier annually since 1946. The collected observations of surface mass balance, glacier velocity and glacier thickness at Profile IV 29 km above the terminus and 4 km above the equilibrium line provide a means to assess the equilibrium nature of the Taku Glacier. Velocity measured over a twelve month span and annual summer velocity measurements completed at a Profile IV from 1950–2006 indicate insignificant variations in velocity seasonally or from year to year. The consistency of velocity over the 56-year period indicates that in the vicinity of the equilibrium line, the flow of the Taku Glacier has been in an equilibrium state. Surface mass balance was positive from 1946–1988 averaging +0.42 m a−1. This led to glacier thickening. From 1988–2006 an important change has occurred and annual balance has been −0.14 m a−1, and the glacier thickness has ceased increasing along Profile IV. Field measurements of ice depth and surface velocity allow calculation of the volume flux at Profile IV. Volume flux is then compared with the surface balance flux from the region of the glacier above Profile IV, determined annually in the field. Above Profile IV the observed mean surface flux is 5.50×108 m3/a (±5%, while the calculated volume flux range flowing through profile IV is 5.00–5.47×108 m3/a. The mean surface flux has been greater than the volume flux, which has led to slow thickening of the Taku Glacier up to 1988. The thickening has not led to a change in the flow of Taku Glacier at Profile IV.

  5. Mass balance, meteorological, ice motion, surface altitude, and runoff data at Gulkana Glacier, Alaska, 1992 balance year

    Science.gov (United States)

    March, R.S.; Trabant, D.C.

    1996-01-01

    The 1992 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier basin were evaluated on the basis of meteorological, hydrological, and glaciological data measured in the basin and are reported herein. Averaged over the glacier, the measured winter snow balance was 0.97 meters on March 26, 1992; the maximum winter snow balance was 1.05 meters on May 19, 1992; the net balance (from September 8, 1991 to August 17, 1992) was -0.29 meters; and the annual balance (October 1, 1991 to September 30, 1992) was -0.38 meters. Ice surface, motion, and altitude changes measured at three index sites document seasonal changes in ice speed and glacier thickness. Annual stream runoff was 1.24 meters averaged over the basin.

  6. Mass balance, meteorological, ice motion, surface altitude, and runoff data at Gulkana Glacier, Alaska, 1994 balance year

    Science.gov (United States)

    March, Rod S.

    1998-01-01

    The 1994 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier basin were evaluated on the basis of meteorological, hydrological, and glaciological data obtained in the basin. Averaged over the glacier, the measured winter snow balance was 1.34 meters on April 29, 1994, 0.9 standard deviation above the long-term average; the maximum winter snow balance, 1.43 meters, was reached on April 18, 1994; the net balance (from September 8, 1993 to September 17, 1994) was -0.72 meter, 0.7 standard deviation below the long-term average. The annual balance (October 1, 1992, to September 30, 1993) was -0.88 meter. Ice-surface motion and altitude changes measured at three index sites document seasonal ice speed and glacier-thickness changes. Annual stream runoff was 1.93 meters averaged over the basin, approximately equal to the long-term average.

  7. Mass balance of nitrogen and potassium in urban groundwater in Central Africa, Yaounde/Cameroon.

    Science.gov (United States)

    Kringel, R; Rechenburg, A; Kuitcha, D; Fouépé, A; Bellenberg, S; Kengne, I M; Fomo, M A

    2016-03-15

    Mass flow of nutrients from innumerous latrines and septic tanks was assessed to best describe the groundwater quality situation in the urban environment of Yaounde. 37 groundwater samples were taken at the end of dry season 2012 and analysed for nutrient related (NO3(-), NH4(+), NO2(-), K(+), Cl(-), HPO4(2-) and TOC) and physico-chemical ambient parameters. A survey on waste water discharge close to water points constrained point sources from sanitation. The results showed that the median of nitrate concentration exceeds the WHO limit. We realized that EC increases from the geogenic background to very high levels in the urban area within short distance, suggesting anthropogenic input. Dug wells showed nitrate and ammonium in equivalent concentrations, indicating incomplete nitrification and mandating their inclusion into water type classification. The mass turnover of nutrients in urban groundwater scales high in comparison to national statistical figures on fertilizer import for 2012. A mass N,K balance for infiltration water overestimates observed concentrations by a factor of 4.5. The marked balance gap is attributed to dynamic non-equilibrium between input and output. Unresolved questions like a) urban sanitation, b) hygiene & health and c) environmental protection urgently call for closing the nutrient cycle. In the light of Cameroonian strategies on rural development, tackling the groundwater nutrient, urban agriculture, food--NEXUS might partially restore urban and periurban ecosystem services under economical constraints and thus improve living conditions.

  8. A mass balance study of the phytoremediation of perchloroethylene-contaminated groundwater

    International Nuclear Information System (INIS)

    A mass balance study was performed under controlled field conditions to investigate the phytoremediation of perchloroethylene (PCE) by hybrid poplar trees. Water containing 7-14 mg L-1 PCE was added to the test bed. Perchloroethylene, trichloroethylene, and cis-dichloroethylene were detected in the effluent at an average of 0.12 mg L-1, 3.9 mg L-1, and 1.9 mg L-1, respectively. The total mass of chlorinated ethenes in the water was reduced by 99%. Over 95% of the recovered chlorine was as free chloride in the soil, indicating near-complete dehalogenation of the PCE. Transpiration, volatilization, and accumulation in the trees were all found to be minor loss mechanisms. In contrast, 98% of PCE applied to an unplanted soil chamber was recovered as PCE in the effluent water or volatilized into the air. These results suggest that phytoremediation can be an effective method for treating PCE-contaminated groundwater in field applications. - A chlorine balance performed on a planted test bed with PCE-contaminated water demonstrated VOC mass reduction of 99% and complete dechlorination.

  9. Mass balance of nitrogen and potassium in urban groundwater in Central Africa, Yaounde/Cameroon.

    Science.gov (United States)

    Kringel, R; Rechenburg, A; Kuitcha, D; Fouépé, A; Bellenberg, S; Kengne, I M; Fomo, M A

    2016-03-15

    Mass flow of nutrients from innumerous latrines and septic tanks was assessed to best describe the groundwater quality situation in the urban environment of Yaounde. 37 groundwater samples were taken at the end of dry season 2012 and analysed for nutrient related (NO3(-), NH4(+), NO2(-), K(+), Cl(-), HPO4(2-) and TOC) and physico-chemical ambient parameters. A survey on waste water discharge close to water points constrained point sources from sanitation. The results showed that the median of nitrate concentration exceeds the WHO limit. We realized that EC increases from the geogenic background to very high levels in the urban area within short distance, suggesting anthropogenic input. Dug wells showed nitrate and ammonium in equivalent concentrations, indicating incomplete nitrification and mandating their inclusion into water type classification. The mass turnover of nutrients in urban groundwater scales high in comparison to national statistical figures on fertilizer import for 2012. A mass N,K balance for infiltration water overestimates observed concentrations by a factor of 4.5. The marked balance gap is attributed to dynamic non-equilibrium between input and output. Unresolved questions like a) urban sanitation, b) hygiene & health and c) environmental protection urgently call for closing the nutrient cycle. In the light of Cameroonian strategies on rural development, tackling the groundwater nutrient, urban agriculture, food--NEXUS might partially restore urban and periurban ecosystem services under economical constraints and thus improve living conditions. PMID:26789374

  10. Climate, not atmospheric deposition, drives the biogeochemical mass-balance of a mountain watershed

    Science.gov (United States)

    Baron, Jill S.; Heath, Jared

    2014-01-01

    Watershed mass-balance methods are valuable tools for demonstrating impacts to water quality from atmospheric deposition and chemical weathering. Owen Bricker, a pioneer of the mass-balance method, began applying mass-balance modeling to small watersheds in the late 1960s and dedicated his career to expanding the literature and knowledge of complex watershed processes. We evaluated long-term trends in surface-water chemistry in the Loch Vale watershed, a 660-ha. alpine/subalpine catchment located in Rocky Mountain National Park, CO, USA. Many changes in surface-water chemistry correlated with multiple drivers, including summer or monthly temperature, snow water equivalent, and the runoff-to-precipitation ratio. Atmospheric deposition was not a significant causal agent for surface-water chemistry trends. We observed statistically significant increases in both concentrations and fluxes of weathering products including cations, SiO2, SO4 2−, and ANC, and in inorganic N, with inorganic N being primarily of atmospheric origin. These changes are evident in the individual months June, July, and August, and also in the combined June, July, and August summer season. Increasingly warm summer temperatures are melting what was once permanent ice and this may release elements entrained in the ice, stimulate chemical weathering with enhanced moisture availability, and stimulate microbial nitrification. Weathering rates may also be enhanced by sustained water availability in high snowpack years. Rapid change in the flux of weathering products and inorganic N is the direct and indirect result of a changing climate from warming temperatures and thawing cryosphere.

  11. Meta-analysis of mass balances examining chemical fate during wastewater treatment.

    Science.gov (United States)

    Heidler, Jochen; Halden, Rolf U

    2008-09-01

    Mass balances are an instructive means for investigating the fate of chemicals during wastewater treatment. In addition to the aqueous-phase removal efficiency (phi), they can inform on chemical partitioning, transformation, and persistence, as well as on the chemical loading to streams and soils receiving, respectively, treated effluent and digested sewage sludge (biosolids). Release rates computed on a per-capita basis can serve to extrapolate findings to a larger scale. This review examines over a dozen mass balances conducted for various organic wastewater contaminants, including prescription drugs, estrogens, fragrances, antimicrobials, and surfactants of differing sorption potential (hydrophobicity), here expressed as the 1-octanol-water partition coefficient (K(OW)) and the organic carbon normalized sorption coefficient (K(OC)). Major challengesto mass balances are the collection of representative samples and accurate quantification of chemicals in sludge. A meta-analysis of peer-reviewed data identified sorption potential as the principal determinant governing chemical persistence in biosolids. Occurrence data for organic wastewater compounds detected in digested sludge followed a simple nonlinear model that required only K(OW) or K(OC) as the input and yielded a correlation coefficient of 0.9 in both instances. The model predicted persistence in biosolids for the majority (> 50%) of the input load of organic wastewater compounds featuring a log10 K(OW) value of greater than 5.2 (log10 K(OC) > 4.4). In contrast, hydrophobicity had no or only limited value for estimating, respectively, phi and the overall persistence of a chemical during conventional wastewater treatment.

  12. Modeling and experimental validation of water mass balance in a PEM fuel cell stack

    DEFF Research Database (Denmark)

    Liso, Vincenzo; Araya, Samuel Simon; Olesen, Anders Christian;

    2016-01-01

    Polymer electrolyte membrane (PEM) fuel cells require good hydration in order to deliver high performance and ensure long life operation. Water is essential for proton conductivity in the membrane which increases by nearly six orders of magnitude from dry to fully hydrated. Adequate water...... management in PEM fuel cell is crucial in order to avoid an imbalance between water production and water removal from the fuel cell. In the present study, a novel mathematical zero-dimensional model has been formulated for the water mass balance and hydration of a polymer electrolyte membrane. This model...

  13. Mass and Energy Balances of Dry Thermophilic Anaerobic Digestion Treating Swine Manure Mixed with Rice Straw

    OpenAIRE

    Sheng Zhou; Jining Zhang; Guoyan Zou; Shohei Riya; Masaaki Hosomi

    2015-01-01

    To evaluate the feasibility of swine manure treatment by a proposed Dry Thermophilic Anaerobic Digestion (DT-AD) system, we evaluated the methane yield of swine manure treated using a DT-AD method with rice straw under different C/N ratios and solid retention time (SRT) and calculated the mass and energy balances when the DT-AD system is used for swine manure treatment from a model farm with 1000 pigs and the digested residue is used for forage rice production. A traditional swine manure trea...

  14. Dynamics and mass balance of El Chichón crater lake, Mexico.

    OpenAIRE

    Rouwet, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Taran, Y.; Instituto de Geofisica, UNAM, Coyoacan, Mexico, D.F. 04510; Inguaggiato, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Varley, N.; Universidad de Colima, Colima, México

    2004-01-01

    The mass balance of El Chichón crater lake is controlled by precipitations, evaporation and seepage through the lake bottom. The main non-meteoric source of water and Cl for the lake is a boiling spring (Soap Pool) discharging saline and neutral water with a variable flow rate from 0 to 30 kg/s inside the El Chichón crater. Variations in lake volume over time were approximately determined from digitized photographic views of the lake using an empirical relationship between depth of t...

  15. Dynamics and mass balance of El Chichón crater lake, Mexico

    OpenAIRE

    Dmitri Rouwet; Yuri A. Taran; Nicholas R. Varley

    2004-01-01

    The mass balance of El Chichón crater lake is controlled by precipitations, evaporation and seepage through the lake bottom. The main non-meteoric source of water and Cl for the lake is a boiling spring (Soap Pool) discharging saline and neutral water with a variable flow rate from 0 to 30 kg/s inside the El Chichón crater. Variations in lake volume over time were approximately determined from digitized photographic views of the lake using an empirical relationship between depth of the lake a...

  16. Well-posedness and exact controllability of the mass balance equations for an extrusion process

    Science.gov (United States)

    Diagne, Mamadou; Shang, Peipei; Wang, Zhiqiang

    2016-07-01

    In this paper, we study the well-posedness and exact controllability of a physical model for a food extrusion process in the isothermal case. The model expresses the mass balance in the extruder chamber and consists of a hyperbolic Partial Differential Equation (PDE) and a nonlinear Ordinary Differential Equation (ODE) whose dynamics describes the evolution of a moving interface. By suitable change of coordinates and fixed point arguments, we prove the existence, uniqueness and regularity of the solution, and finally the exact controllability of the coupled system.

  17. NETPATH-WIN: an interactive user version of the mass-balance model, NETPATH

    Science.gov (United States)

    El-Kadi, A. I.; Plummer, L.N.; Aggarwal, P.

    2011-01-01

    NETPATH-WIN is an interactive user version of NETPATH, an inverse geochemical modeling code used to find mass-balance reaction models that are consistent with the observed chemical and isotopic composition of waters from aquatic systems. NETPATH-WIN was constructed to migrate NETPATH applications into the Microsoft WINDOWS® environment. The new version facilitates model utilization by eliminating difficulties in data preparation and results analysis of the DOS version of NETPATH, while preserving all of the capabilities of the original version. Through example applications, the note describes some of the features of NETPATH-WIN as applied to adjustment of radiocarbon data for geochemical reactions in groundwater systems.

  18. Evaluation of total phosphorus mass balance in the lower Boise River and selected tributaries, southwestern Idaho

    Science.gov (United States)

    Etheridge, Alexandra B.

    2013-01-01

    he U.S. Geological Survey (USGS), in cooperation with Idaho Department of Environmental Quality, developed spreadsheet mass-balance models for total phosphorus using results from three synoptic sampling periods conducted in the lower Boise River watershed during August and October 2012, and March 2013. The modeling reach spanned 46.4 river miles (RM) along the Boise River from Veteran’s Memorial Parkway in Boise, Idaho (RM 50.2), to Parma, Idaho (RM 3.8). The USGS collected water-quality samples and measured streamflow at 14 main-stem Boise River sites, two Boise River north channel sites, two sites on the Snake River upstream and downstream of its confluence with the Boise River, and 17 tributary and return-flow sites. Additional samples were collected from treated effluent at six wastewater treatment plants and two fish hatcheries. The Idaho Department of Water Resources quantified diversion flows in the modeling reach. Total phosphorus mass-balance models were useful tools for evaluating sources of phosphorus in the Boise River during each sampling period. The timing of synoptic sampling allowed the USGS to evaluate phosphorus inputs to and outputs from the Boise River during irrigation season, shortly after irrigation ended, and soon before irrigation resumed. Results from the synoptic sampling periods showed important differences in surface-water and groundwater distribution and phosphorus loading. In late August 2012, substantial streamflow gains to the Boise River occurred from Middleton (RM 31.4) downstream to Parma (RM 3.8). Mass-balance model results indicated that point and nonpoint sources (including groundwater) contributed phosphorus loads to the Boise River during irrigation season. Groundwater exchange within the Boise River in October 2012 and March 2013 was not as considerable as that measured in August 2012. However, groundwater discharge to agricultural tributaries and drains during non-irrigation season was a large source of discharge and

  19. Integrated configurable equipment selection and line balancing for mass production with serial-parallel machining systems

    Science.gov (United States)

    Battaïa, Olga; Dolgui, Alexandre; Guschinsky, Nikolai; Levin, Genrikh

    2014-10-01

    Solving equipment selection and line balancing problems together allows better line configurations to be reached and avoids local optimal solutions. This article considers jointly these two decision problems for mass production lines with serial-parallel workplaces. This study was motivated by the design of production lines based on machines with rotary or mobile tables. Nevertheless, the results are more general and can be applied to assembly and production lines with similar structures. The designers' objectives and the constraints are studied in order to suggest a relevant mathematical model and an efficient optimization approach to solve it. A real case study is used to validate the model and the developed approach.

  20. The potential role of mass balance models for the management of upwelling ecosystems

    DEFF Research Database (Denmark)

    Jarre, Astrid

    1998-01-01

    Upwelling ecosystems are productive fishing grounds, contributing >30% to the world's catch of marine fish. A set of seven trophic mass balance models of productive subsystems of the four largest upwelling areas is used to demonstrate key features of the modeling process and the analysis...... set of species interactions, and its impact can thus be readily compared to that of other piscivores in the ecosystem. This approach consequently allows us to assess the ecological sustainability of a fishery. It therefore addresses the Code of Conduct for Responsible Fisheries recently published...

  1. Using a Mass Balance to Determine the Potency Loss during the Production of a Pharmaceutical Blend

    OpenAIRE

    Mackaplow, Michael B.

    2010-01-01

    The manufacture of a blend containing the active pharmaceutical ingredient (API) and inert excipients is a precursor for the production of most pharmaceutical capsules and tablets. However, if there is a net water gain or preferential loss of API during production, the potency of the final drug product may be less than the target value. We use a mass balance to predict the mean potency loss during the production of a blend via wet granulation and fluidized bed drying. The result is an explici...

  2. Mass balance, meteorological, ice motion, surface altitude, runoff, and ice thickness data at Gulkana Glacier, Alaska, 1995 balance year

    Science.gov (United States)

    March, Rod S.

    2000-01-01

    The 1995 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier basin were evaluated on the basis of meteorological, hydrological, and glaciological data obtained in the basin. Averaged over the glacier, the measured winter snow balance was 0.94 meter on April 19, 1995, 0.6 standard deviation below the long-term average; the maximum winter snow balance, 0.94 meter, was reached on April 25, 1995; the net balance (from September 18, 1994 to August 29, 1995) was -0.70 meter, 0.76 standard deviation below the long-term average. The annual balance (October 1, 1994, to September 30, 1995) was -0.86 meter. Ice-surface motion and altitude changes measured at three index sites document seasonal ice speed and glacier-thickness changes. Annual stream runoff was 2.05 meters averaged over the basin, approximately equal to the long-term average. The 1976 ice-thickness data are reported from a single site near the highest measurement site (180 meters thick) and from two glacier cross profiles near the mid-glacier (270 meters thick on centerline) and low glacier (150 meters thick on centerline) measurement sites. A new area-altitude distribution determined from 1993 photogrammetry is reported. Area-averaged balances are reported from both the 1967 and 1993 area-altitude distribution so the reader may directly see the effect of the update. Briefly, loss of ablation area between 1967 and 1993 results in a larger weighting being applied to data from the upper glacier site and hence, increases calculated area-averaged balances. The balance increase is of the order of 15 percent for net balance.

  3. Herfried Hoinkes: pioneer of degree-day methods to calculate glacier mass-balance from air temperature

    OpenAIRE

    R. J. Braithwaite

    2015-01-01

    Herfried Hoinkes (1916 to 1975) was a glacier researcher and university teacher who made great contributions to the early development of modern glaciology but I concentrate on his work on the mass balance of an Austrian glacier Hintereisferner. In a series of paper from 1962 to 1975, he showed that the mass balance is strongly correlated with positive degree-day (PDD) totals extrapolated from a nearby climate station. He achieved further improvements in correlations by accounting for fresh sn...

  4. Critical loads for nitrogen to avoid eutrophication: assessment of the mass balance approach using the Aber site, N. Wales

    OpenAIRE

    B. A. Emmett; Reynolds, B.

    1995-01-01

    The nitrogen critical load to avoid eutrophication has been calculated for a 32 year old stand of Sitka spruce in N.Wales which has been intensively studied for 4 years. Default and measured values for the mass balance equation have been used to calculate a range of probable nitrogen critical load values which have then been compared to the range estimated from methods other than the mass balance approach.

  5. Batura-Glacier - mass balance and 'Karakoram Anomaly' (Upper Hunza, Karakoram)

    Science.gov (United States)

    Boerst, U.; Winiger, M.; Bookhagen, B.

    2013-12-01

    In line with an almost worldwide trend the (non-surging) glaciers in the Hindukush-Karakoram-Himalaya Range manifest a remarkable down melting of their tongues and retreating of their terminuses in the last few decades. A series of recent studies prove an overall negative mass balance for most of the Himalayan glaciers. Contrary to these statements various publications register stable or positive mass balances for a number of glaciers located in the NW-Karakoram Mountains - postulating the so-called 'Karakoram-Anomaly'. Unlike the many investigations in the Himalaya, the Karakoram records very few detailed local investigations emphasizing the spatial and temporal development of glaciers. This presentation focuses on the Batura Glacier in NW-Karakorum in Gilgit-Baltistan (Pakistan). With a west-to-east extension of ~ 57 km and an elevation range of 5.3 km (2.500 - 7.800 masl), the Batura Glacier belongs to the worldwide largest glaciers in the mid and low latitudes. Detailed mapping and further ground-based investigations have been carried out in the 1920ies, 1953/59, 1974/5 and in the past few years by different research teams. In order to determine the glacier's mass balance for the last 50 years we relied on Digital Elevation Models (DEMs): digitized maps from 1959 and 1974 are compared to DEMs derived through stereogrammetry from ASTER-scenes for 2001, 2006, 2008, 2010 and 2011. The ASTER-DEMs were post-processed with various correction methods and techniques to insure the relative DEM comparability and include corrections for aspect, altitude, and tilt. Next, we calculated surface differences from the ice and snow-free areas with respect to the SRTM C-Band DEM. Our remote sensing techniques are supplemented by differential GPS measurements and ice-surface profiles from 2013 as well as by multi-temporal photography matching. Preliminary results indicate a significant down melting of the glacier tongue from 1959 to the present day and acceleration during the past

  6. A mass-balance model to separate and quantify colloidal and solute redistributions in soil

    Science.gov (United States)

    Bern, C.R.; Chadwick, O.A.; Hartshorn, A.S.; Khomo, L.M.; Chorover, J.

    2011-01-01

    Studies of weathering and pedogenesis have long used calculations based upon low solubility index elements to determine mass gains and losses in open systems. One of the questions currently unanswered in these settings is the degree to which mass is transferred in solution (solutes) versus suspension (colloids). Here we show that differential mobility of the low solubility, high field strength (HFS) elements Ti and Zr can trace colloidal redistribution, and we present a model for distinguishing between mass transfer in suspension and solution. The model is tested on a well-differentiated granitic catena located in Kruger National Park, South Africa. Ti and Zr ratios from parent material, soil and colloidal material are substituted into a mixing equation to quantify colloidal movement. The results show zones of both colloid removal and augmentation along the catena. Colloidal losses of 110kgm-2 (-5% relative to parent material) are calculated for one eluviated soil profile. A downslope illuviated profile has gained 169kgm-2 (10%) colloidal material. Elemental losses by mobilization in true solution are ubiquitous across the catena, even in zones of colloidal accumulation, and range from 1418kgm-2 (-46%) for an eluviated profile to 195kgm-2 (-23%) at the bottom of the catena. Quantification of simultaneous mass transfers in solution and suspension provide greater specificity on processes within soils and across hillslopes. Additionally, because colloids include both HFS and other elements, the ability to quantify their redistribution has implications for standard calculations of soil mass balances using such index elements. ?? 2011.

  7. Sugarcane bagasse pretreatment using three imidazolium-based ionic liquids; mass balances and enzyme kinetics

    Directory of Open Access Journals (Sweden)

    Karatzos Sergios

    2012-08-01

    Full Text Available Abstract Background Effective pretreatment is key to achieving high enzymatic saccharification efficiency in processing lignocellulosic biomass to fermentable sugars, biofuels and value-added products. Ionic liquids (ILs, still relatively new class of solvents, are attractive for biomass pretreatment because some demonstrate the rare ability to dissolve all components of lignocellulosic biomass including highly ordered (crystalline cellulose. In the present study, three ILs, 1-butyl-3-methylimidazolium chloride ([C4mim]Cl, 1-ethyl-3-methylimidazolium chloride ([C2mim]Cl, 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc are used to dissolve/pretreat and fractionate sugarcane bagasse. In these IL-based pretreatments the biomass is completely or partially dissolved in ILs at temperatures greater than 130°C and then precipitated by the addition of an antisolvent to the IL biomass mixture. For the first time mass balances of IL-based pretreatments are reported. Such mass balances, along with kinetics data, can be used in process modelling and design. Results Lignin removals of 10% mass of lignin in bagasse with [C4mim]Cl, 50% mass with [C2mim]Cl and 60% mass with [C2mim]OAc, are achieved by limiting the amount of water added as antisolvent to 0.5 water:IL mass ratio thus minimising lignin precipitation. Enzyme saccharification (24 h, 15FPU yields (% cellulose mass in starting bagasse from the recovered solids rank as: [C2mim]OAc(83% > >[C2mim]Cl(53% = [C4mim]Cl(53%. Composition of [C2mim]OAc-treated solids such as low lignin, low acetyl group content and preservation of arabinosyl groups are characteristic of aqueous alkali pretreatments while those of chloride IL-treated solids resemble aqueous acid pretreatments. All ILs are fully recovered after use (100% mass as determined by ion chromatography. Conclusions In all three ILs regulated addition of water as an antisolvent effected a polysaccharide enriched precipitate since some of the lignin

  8. Improving Surface Mass Balance Over Ice Sheets and Snow Depth on Sea Ice

    Science.gov (United States)

    Koenig, Lora Suzanne; Box, Jason; Kurtz, Nathan

    2013-01-01

    Surface mass balance (SMB) over ice sheets and snow on sea ice (SOSI) are important components of the cryosphere. Large knowledge gaps remain in scientists' abilities to monitor SMB and SOSI, including insufficient measurements and difficulties with satellite retrievals. On ice sheets, snow accumulation is the sole mass gain to SMB, and meltwater runoff can be the dominant single loss factor in extremely warm years such as 2012. SOSI affects the growth and melt cycle of the Earth's polar sea ice cover. The summer of 2012 saw the largest satellite-recorded melt area over the Greenland ice sheet and the smallest satellite-recorded Arctic sea ice extent, making this meeting both timely and relevant.

  9. The pattern of anthropogenic signal emergence in Greenland Ice Sheet surface mass balance

    Science.gov (United States)

    Fyke, Jeremy G.; Vizcaíno, Miren; Lipscomb, William H.

    2014-08-01

    Surface mass balance (SMB) trends influence observed Greenland Ice Sheet (GrIS) mass loss, but the component of these trends related to anthropogenic forcing is unclear. Here we study the simulated spatial pattern of emergence of an anthropogenically derived GrIS SMB signal between 1850 and 2100 using the Community Earth System Model. We find emergence timing heterogeneity, with a bimodal structure reflecting interior snowfall increases against a background of low SMB variability, and peripheral surface melting increases against a backdrop of high SMB variability. We also find a nonemerging intermediate region. We conclude that (1) a bimodal pattern of GrIS SMB change will unambiguously reflect the impact of anthropogenic forcing; (2) present-day peripheral and interior SMB trends likely have an underlying anthropogenically forced component; (3) local emergence occurs well before emergence of a spatially integrated signal; and (4) the GrIS summit region may be an ideal location for monitoring regional/global climate change.

  10. Densification and refreezing in the percolation zone of the Greenland Ice Sheet: implications for mass balance measurements

    OpenAIRE

    Parry, Victoria

    2009-01-01

    In order to increase coverage, mass balance changes of the world’s ice sheets are increasingly derived from surface elevation changes measured via satellite. Across the percolation zone of the Greenland Ice Sheet, meltwater, percolation and refreezing cause a re-distribution of mass through densification which may result in elevation change with no associated mass loss. Therefore, densification processes need to be quantified, spatially and temporally, and accounted for in mass...

  11. Mass balance, meteorological, ice motion, surface altitude, and runoff data at Gulkana Glacier, Alaska, 1993 balance year

    Science.gov (United States)

    March, Rod; Trabant, Dennis

    1997-01-01

    The 1993 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier basin were evaluated on the basis of meteorological, hydrological, and glaciological data measured in the basin and are reported herein. Averaged over the glacier, the measured winter snow balance was 0.81 meter on March 31, 1993, 1.2 standard deviations below the long-term average; the maximum winter snow balance, 0.84 meter, was reached on May 10, 1993 and remained until May 11, 1993; the net balance (from August 18, 1992 to September 8, 1993) was 1.80 meters, the most negative balance year on record at 2.8 standard deviations below the long-term average. The annual balance (October 1, 1992 to September 30, 1993) was 1.64 meters. Ice-surface motion and altitude changes measured at three index sites document seasonal ice speed and glacier thickness changes. Annual stream runoff was 1.996 meters averaged over the basin, 0.2 standard deviations above the long-term average.

  12. Mass balance of the Greenland ice sheet - a study of ICESat data, surface density and firn compaction modelling

    DEFF Research Database (Denmark)

    Sørensen, L. S.; Simonsen, Sebastian Bjerregaard; Nielsen, K.;

    2010-01-01

    ICESat has provided surface elevation measurements of the ice sheets since the launch in January 2003, resulting in a unique data set for monitoring the changes of the cryosphere. Here we present a novel method for determining the mass balance of the Greenland ice sheet derived from ICESat...... in estimating the mass balance of the Greenland ice sheet. We find firn dynamics and surface densities to be important factors in deriving the mass loss from remote sensing altimetry. The volume change derived from ICESat data is corrected for firn compaction, vertical bedrock movement and an intercampaign...... boundary conditions. We find an annual mass loss of the Greenland ice sheet of 210 ± 21 Gt yr-1 in the period from October 2003 to March 2008. This result is in good agreement with other studies of the Greenland ice sheet mass balance, based on different remote sensing techniques....

  13. Impact of sublimation losses in the mass balance of glaciers in semi-arid mountain regions

    Science.gov (United States)

    Ayala, Alvaro; Pellicciotti, Francesca; Burlando, Paolo; MacDonell, Shelley; McPhee, James

    2016-04-01

    Glaciers in semiarid mountain regions may lose an important part of their winter snow accumulation through sublimation processes that are enhanced by the high-elevation, intense radiation and dry atmosphere of these environments. As glaciers in these regions secure freshwater resources to lower valleys during summer and drought periods, it is important to advance in a detailed quantification of their sublimation losses. However, logistical concerns and complex meteorological features make the measuring and modelling of glacier mass balances a difficult task. In this study, we estimated the spring-summer mass balances of Tapado and Juncal Norte glaciers in the semiarid Andes of north-central Chile by running a distributed energy balance model that accounts for melt, refreezing and sublimation from the surface and blowing snow. Meteorological input data were available from on-glacier Automatic Weather Stations (AWS) that were installed during the ablation season of years 2005-06, 2008-09, 2013-14 and 2014-15. Snow pits, ablation stakes and a time-lapse camera that provided surface albedo were also available. Distributed air temperature and wind speed were dynamically downscaled from NASA MERRA reanalysis using the software WINDSIM and validated against the data from the AWSs. The rest of the meteorological variables were distributed using statistical relations with air temperature derived from the AWSs data. Initial snow conditions were estimated using satellite images and distributed manual snow depth measurements. Preliminary results show that total ablation diminishes with elevation and that, during the early ablation season (October-November), melt is the main ablation component below 4500 m with sublimation dominating the ablation above this elevation. Above 4500 m an important fraction of meltwater refreezes during night. As the ablation season advances (December-February), melt extends to higher elevations, refreezing plays a smaller role and sublimation is

  14. Uncertainty analysis on simple mass balance model to calculate critical loads for soil acidity

    International Nuclear Information System (INIS)

    Simple mass balance equations (SMBE) of critical acid loads (CAL) in forest soil were developed to assess potential risks of air pollutants to ecosystems. However, to apply SMBE reliably at large scales, SMBE must be tested for adequacy and uncertainty. Our goal was to provide a detailed analysis of uncertainty in SMBE so that sound strategies for scaling up CAL estimates to the national scale could be developed. Specifically, we wanted to quantify CAL uncertainty under natural variability in 17 model parameters, and determine their relative contributions in predicting CAL. Results indicated that uncertainty in CAL came primarily from components of base cation weathering (BCw; 49%) and acid neutralizing capacity (46%), whereas the most critical parameters were BCw base rate (62%), soil depth (20%), and soil temperature (11%). Thus, improvements in estimates of these factors are crucial to reducing uncertainty and successfully scaling up SMBE for national assessments of CAL. - A comprehensive uncertainty analysis, with advanced techniques and full list and full value ranges of all individual parameters, was used to examine a simple mass balance model and address questions of error partition and uncertainty reduction in critical acid load estimates that were not fully answered by previous studies

  15. A mass balance study on nitrification and deammonification in vertical flow constructed wetlands treating landfill leachate.

    Science.gov (United States)

    Sun, G; Austin, D

    2007-01-01

    A laboratory-scale, mass-balance study was carried out on the transformation of nitrogenous pollutants in four vertical flow wetland columns. Landfill leachate containing low organic matter, but a high concentration of ammoniacal-nitrogen, was treated under dissolved oxygen concentrations close to saturation. Influent total nitrogen (TN) comprised ammoniacal-nitrogen with less than 1% nitrate and nitrite, negligible organic nitrogen, and very low BOD. Nitrification occurred in three of the four columns. There was a substantial loss of total nitrogen (52%) in one column, whereas other columns exhibited zero to minor losses (< 12%). Nitrogen loss under study conditions was unexpected. Two hypotheses are proposed to account for it: (1) either the loss of TN is attributed to nitrogen transformation into a form (provisionally termed alpha-nitrogen) that is undetectable by the analytical methods used; or (2) the loss is caused by microbial denitrification or deammonification. By elimination and stoichiometric mass balance calculations, completely autotrophic nitrogen-removal over nitrite (CANON) deammonification is confirmed as responsible for nitrogen loss in one column. This result reveals that CANON can be native to aerobic engineered wetland systems treating high ammonia, low organic content wastewater.

  16. Stable climate and surface mass balance in Svalbard over 1979–2013 despite the Arctic warming

    Directory of Open Access Journals (Sweden)

    C. Lang

    2015-01-01

    (Model for Interdisciplinary Research on Climate global model (MARMIROC5 from the CMIP5 (Coupled Model Intercomparison Project database, we have modelled the climate and surface mass balance of Svalbard at a 10 km resolution over 1979–2013. The integrated total surface mass balance (SMB over Svalbard modelled by MARERA is negative (−1.6 Gt yr−1 with a large interannual variability (7.1 Gt but, unlike over Greenland, there has been no acceleration of the surface melt over the past 35 years because of the recent change in atmospheric circulation bringing northwesterly flows in summer over Svalbard, contrasting the recent observed Arctic warming. However, in 2013, the atmospheric circulation changed to a south–southwesterly flow over Svalbard causing record melt, SMB (−20.4 Gt yr−1 and summer temperature. MIROC5 is significantly colder than ERA-Interim over 1980–2005 but MARMIROC5 is able to improve the near-surface MIROC5 results by simulating not significant SMB differences with MARERA over 1980–2005. On the other hand, MIROC5 does not represent the recent atmospheric circulation shift in summer and induces in MARMIROC5 a significant trend of decreasing SMB (−0.6 Gt yr−2 over 1980–2005.

  17. Geochemical investigation of weathering processes in a forested headwater catchment: Mass-balance weathering fluxes

    Science.gov (United States)

    Jones, B.F.; Herman, J.S.

    2008-01-01

    Geochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and oxyhydroxides, and solute fluxes (Meunier and Velde, 1979). The chemical composition of the clay-mineral product is often ignored. However, in earlier investigations, the saprolitic weathering profile at the South Fork Brokenback Run (SFBR) watershed, Shenandoah National Park, Virginia, was characterized extensively in terms of its mineralogical and chemical composition (Piccoli, 1987; Pochatila et al., 2006; Jones et al., 2007) and its basic hydrology. O'Brien et al. (1997) attempted to determine the contribution of primary mineral weathering to observed stream chemistry at SFBR. Mass-balance model results, however, could provide only a rough estimate of the weathering reactions because idealized mineral compositions were utilized in the calculations. Making use of detailed information on the mineral occurrence in the regolith, the objective of the present study was to evaluate the effects of compositional variation on mineral-solute mass-balance modelling and to generate plausible quantitative weathering reactions that support both the chemical evolution of the surface water and ground water in the catchment, as well as the mineralogical evolution of the weathering profile. ?? 2008 The Mineralogical Society.

  18. Long term mass balance of the Helheim and Kangerdlugssuaq glaciers in southeast Greenland

    Science.gov (United States)

    Khan, Shfaqat Abbas; Fitzner, Antje; Kjær, Kurt; Korsgaard, Niels; Aschwanden, Andy; Bjørk, Anders; Bevan, Suzanne; Kjeldsen, Kristian; Bueler, Edward; Luckman, Adrian; van den Broeke, Michiel

    2013-04-01

    Observations over the past decade show huge ice loss associated with speeding up of glaciers in southeast Greenland in 2003, followed by a deceleration in 2006. These short-term episodic dynamic perturbations have a major impact on the mass balance at decadal scale. However, to improve the projection of future sea level rise, a long-term data record that reveals the mass balance between episodic events is required. Here, we extend the observational record of marginal thinning of Helheim glacier (HG) and Kangerdlugssuaq glacier (KG) from 7 to 30 years. Our measurements reveal that, although the frontal portion of HG thinned by more than 100 m during 2003-2006, it thickened by more than 50 m during 1981-1997. During the same periods, KG was stable until 1998 and experienced major thinning only after 2003. Analyses of their sensitivity to sea surface temperature (SST) anomalies and variations in air temperature suggest that both outlet glaciers respond immediately to small fluctuations in both the SST and air temperature. Furthermore, we compare our observations of ice flow speed and elevation changes with predictions based on the The Parallel Ice Sheet Model (PISM) software.

  19. Long Term Sea Level Change and Water Mass Balance in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    RONG Zengrui; LIU Yuguang; ZONG Haibo; XIU Peng

    2009-01-01

    Sea level anomalies observed by altimeter during the 1993-2006 period, thermosterie sea level anomalies estimated by using subsurface temperature data produced by Ishii and SODA reanalysis data, tide gauge records and HOAPS freshwater flux data were analyzed to investigate the long term sea level change and the water mass balance in the South China Sea. The altimeter-observed sea level showed a rising rate of (3.5±0.9)mm yr-1 during the period 1993-2006, but this figure was considered to have been highly distorted by the relatively short time interval and the large inter-decadal variability, which apparently exists in both the thermosteric sea level and the observed sea level. Long term thermosteric sea level from 1945 to 2004 gave a rising rate of 0.15±0.06 mmyr-1. Tide gauge data revealed this discrepancy and the regional distributions of the sea-level trends. Both the 'real' and the thermosteric sea level showed a good correspondence to ENSO: decreasing during E1 Nifio years and increasing during La Nina years. Amplitude and phase differences between the 'real' sea level and the thermosteic sea level were substantially revealed on both seasonal and interannual time scales. As one of the possible factors, the freshwater flux might play an important role in balancing the water mass.

  20. Distributed modeling of snow cover mass and energy balance in the Rheraya watershed (High Atlas, Morocco)

    Science.gov (United States)

    Marchane, Ahmed; Gascoin, Simon; Jarlan, Lionel; Hanich, Lahoucine

    2016-04-01

    The mountains of the High Moroccan Atlas represent an important source of water for the neighboring arid plains. Despite the importance of snow in the regional water balance, few studies were devoted to the modeling of the snow cover at the watershed scale. This type of modeling is necessary to characterize the contribution of snowmelt to water balance and understanding its sensitivity to natural and human-induced climate fluctuations. In this study, we applied a spatially-distributed model of the snowpack evolution (SnowModel, Liston & Elder 2006) on the Rheraya watershed (225 km²) in the High Atlas in order to simulate the mass and energy balance of the snow cover and the evolution of snow depth over a full season (2008-2009). The model was forced by 6 meteorological stations. The model was evaluated locally at the Oukaimeden meteorological station (3230 m asl) where snow depth is recorded continuously. To evaluate the model at the watershed scale we used the daily MODIS snow cover products and a series of 15 cloud-free optical images acquired by the FORMOSAT-2 satellite at 8-m resolution from February to June 2009. The results showed that the model is able to simulate the snow depth in the Oukaimeden station for the 2008-2009 season, and also to simulate the spatial and temporal variation of of the snow cover area in the watershed Rheraya. Based on the model output we examine the importance of the snow sublimation on the water balance at the watershed scale.

  1. Dual-sensor mapping of mass balance on Russia's northernmost ice caps

    Science.gov (United States)

    Nikolskiy, D.; Malinnikov, V.; Sharov, A.; Ukolova, M.

    2012-04-01

    Mass balance of Russia's northernmost ice caps is poorly known and scarcely mapped. Thorough information about glacier fluctuations in the outer periphery of Russian shelf seas is both lacking and highly desired since it may constitute the relevant benchmark for judging and projecting climate change impacts in the entire Arctic. The present study is focussed on geodetic measurements and medium-scale mapping of the mass balance on a dozen insular ice caps, some large and some smaller, homogeneously situated along the Eurasian boundary of Central Arctic Basin. The study region extends for approx. 2.200 km from Victoria and Arthur islands in the west across Rudolph, Eva-Liv, Ushakova, Schmidt and Komsomolets islands in the north to Bennett and Henrietta islands in the east thereby comprising the most distant and least studied ice caps in the Russian Arctic. The situation of insular ice masses close to the edge of summer minimum sea ice proved helpful in analysing spatial asymmetry of glacier accumulation signal. The overall mapping of glacier elevation changes and quantification of mass balance characteristics in the study region was performed by comparing reference elevation models of study glaciers derived from Russian topographic maps 1:200,000 (CI = 20 or 40 m) representing the glacier state as in the 1950s-1960s with modern elevation data obtained from satellite radar interferometry and lidar altimetry. In total, 14 ERS and 4 TanDEM-X high-quality SAR interferograms of 1995/96 and 2011 were acquired, processed in the standard 2-pass DINSAR manner, geocoded, calibrated, mosaicked and interpreted using reference elevation models and co-located ICESat altimetry data of 2003-2010. The DINSAR analysis revealed the existence of fast-flowing outlet glaciers at Arthur, Rudolph, Eva-Liv and Bennett islands. The calculation of separate mass-balance components is complicated in this case because of generally unknown glacier velocities and ice discharge values for the mid-20

  2. A LEGO Watt Balance: An apparatus to demonstrate the definition of mass based on the new SI

    CERN Document Server

    Chao, L S; Newell, D B; Pratt, J R; Sineriz, G; Seifert, F; Cao, A; Haddad, D; Zhang, X

    2014-01-01

    A global effort to redefine our International System of Units (SI) is underway and the change to the new system is expected to occur in 2018. Within the newly redefined SI, the present base units will still exist but be derived from fixed numerical values of seven reference constants. More specifically, the unit of mass, the kilogram, will be realized through a fixed value of the Planck constant $h$. For instance, a watt balance can be used to realize the kilogram unit of mass within a few parts in $10^8$. Such a balance has been designed and constructed at the National Institute of Standards and Technology. For educational outreach and to demonstrate the principle, we have constructed a LEGO tabletop watt balance capable of measuring a gram size mass to 1 % relative uncertainty. This article presents the design, construction, and performance of the LEGO watt balance and its ability to determine $h$

  3. Recent evolution and mass balance of Cordón Martial glaciers, Cordillera Fueguina Oriental

    Science.gov (United States)

    Strelin, Jorge; Iturraspe, Rodolfo

    2007-10-01

    Past and present glacier changes have been studied at Cordón Martial, Cordillera Fueguina Oriental, Tierra del Fuego, providing novel data for the Holocene deglaciation history of southern South America and extrapolating as well its future behavior based on predicted climatic changes. Regional geomorphologic and stratigraphic correlations indicate that the last glacier advance deposited the ice-proximal ("internal") moraines of Cordón Martial, around 330 14C yr BP, during the Late Little Ice Age (LLIA). Since then glaciers have receded slowly, until 60 years ago, when major glacier retreat started. There is a good correspondence for the past 100 years between the surface area variation of four small cirque glaciers at Cordón Martial and the annual temperature and precipitation data of Ushuaia. Between 1984 and 1998, Martial Este Glacier lost 0.64 ± 0.02 × 10 6 m 3 of ice mass (0.59 ± 0.02 × 10 6 m 3 w.e.), corresponding to an average ice thinning of 7.0 ± 0.2 m (6.4 ± 0.2 m w.e), according to repeated topographic mapping. More detailed climatic data have been obtained since 1998 at the Martial Este Glacier, including air temperature, humidity and solar radiation. These records, together with the monthly mass balance measured since March 2000, document the annual response of the Martial Este Glacier to the climate variation. Mass balances during hydrological years were positive in 2000, negative in 2001 and near equilibrium in 2002. Finally, using these data and the regional temperature trend projections, modeled for different future scenarios by the Atmosphere-Ocean Model (GISS-NASA/GSFC), potential climatic-change effects on this mountain glacier were extrapolated. The analysis shows that only the Martial Este Glacier may survive this century.

  4. Does mechanistic modeling of filter strip pesticide mass balance and degradation processes affect environmental exposure assessments?

    Science.gov (United States)

    Muñoz-Carpena, Rafael; Ritter, Amy; Fox, Garey A; Perez-Ovilla, Oscar

    2015-11-01

    Vegetative filter strips (VFS) are a widely adopted practice for limiting pesticide transport from adjacent fields to receiving waterbodies. The efficacy of VFS depends on site-specific input factors. To elucidate the complex and non-linear relationships among these factors requires a process-based modeling framework. Previous research proposed linking existing higher-tier environmental exposure models with a well-tested VFS model (VFSMOD). However, the framework assumed pesticide mass stored in the VFS was not available for transport in subsequent storm events. A new pesticide mass balance component was developed to estimate surface pesticide residue trapped in the VFS and its degradation between consecutive runoff events. The influence and necessity of the updated framework on acute and chronic estimated environmental concentrations (EECs) and percent reductions in EECs were investigated across three, 30-year U.S. EPA scenarios: Illinois corn, California tomato, and Oregon wheat. The updated framework with degradation predicted higher EECs than the existing framework without degradation for scenarios with greater sediment transport, longer VFS lengths, and highly sorbing and persistent pesticides. Global sensitivity analysis (GSA) assessed the relative importance of mass balance and degradation processes in the context of other input factors like VFS length (VL), organic-carbon sorption coefficient (Koc), and soil and water half-lives. Considering VFS pesticide residue and degradation was not important if single, large runoff events controlled transport, as is typical for higher percentiles considered in exposure assessments. Degradation processes become more important when considering percent reductions in acute or chronic EECs, especially under scenarios with lower pesticide losses.

  5. Glacial changes and glacier mass balance at Gran Campo Nevado, Chile during recent decades

    Science.gov (United States)

    Schneider, C.; Schnirch, M.; Kilian, R.; Acuña, C.; Casassa, G.

    2003-04-01

    /2001 and 8.5 m in 2001/2002. This is in excellent accordance (+/-4%) with measurements at 12 m-long ablation stakes that have been drilled into the glacier. The DEM and a GIS layer defining glacier boundaries provide the basis for the distributed calculation of glacier mass balance. It was computed from the degree-day-model by applying elevation-corrected temperature and precipitation data to each grid point of the DEM. Furthermore, weather station data from Punta Arenas and Faro Evangelistas since 1905 enables to estimate the mass balance of Glaciar Lengua for almost one century. The derived mass balance record indicates a slightly negative mass balance during most of the 20th century. This in excellent agreement with the result obtained from aerial photography and GIS. The work was conducted as part of the international and interdisciplinary working group “Gran Campo Nevado” and was supported by the German Research Foundation (DFG).

  6. Sensitivity of annual mass balance gradient and Hypsometry to the changing climate: the case of Dokriani Glacier, central Himalaya, India

    Science.gov (United States)

    Pratap, B.

    2015-12-01

    The glacier mass balance is undelayed, unfiltered and direct method to assess the impact of climate change on the glaciers. Many studies suggest that some of the Himalayan glaciers have lost their mass at an increased rate during the past few decades. Furthermore, the mass balance gradient and hypsometric analysis are important to understand the glacier response towards climatic perturbations. Our long term in-situ monitoring on the Dokriani Glacier provides great insights to understand the variability in central Himalayan glaciers. We report the relationship between glacier hypsometry and annual mass balance gradient (12 years) to understand the glacier's response towards climate change. Dokriani Glacier in the Bhagirathi basin is a small (7 km2) NNW exposed glacier in the western part of central Himalaya, India. The study analysed the annual balance, mass balance gradient and length changes observed during first decade of 21st century (2007-2013) and compare with the previous observations of 1990s (1992-2000). A large spatial variability in the mass balance gradients of two different periods has been observed. The equilibrium-line altitude (ELA) was fluctuated between 5000 and 5100 m a.s.l. and the derived time averaged ELA (ELAn) and balance budget ELA (ELA0) were 5075 and 4965 m a.s.l respectively during 1992-2013. The observed time-averaged accumulation-area ratio (AARn) and balance budget AAR (AAR0) were 0.67 and 0.72 respectively during 1992-2013. The higher value of AAR comprises due to flat and broader accumulation area (4.50 km2) of the glacier. Although, having larger accumulation area, the glacier has faced strong mass wasting with average annual ablation of -1.82 m w.e. a-1 in the ablation zone as compare to residual average annual accumulation of 0.41 m w.e. a-1. Based on the annual mass balance series (12 years) Dokriani Glacier has continuous negative annual balances with monotonically negative cumulative mass loss of -3.86 m w.e with the average

  7. Greenland Ice Sheet Mass Balance: Distribution of Increased Mass Loss with Climate Warming; 2003-07 Versus 1992-2002

    Science.gov (United States)

    Zwally, H. Jay; Li, Jun; Benner, Anita C.; Beckley, Matthew; Cornejo, Helen G.; DiMarzio, John; Giovinetto, Mario B.; Neumann, Thomas A.; Robbins, John; Saba, Jack L.; Yi, Donghui; Wang, Weili

    2011-01-01

    We derive mass changes of the Greenland ice sheet (GIS) for 2003-07 from ICESat laser altimetry and compare them with results for 1992-2002 from ERS radar and airborne laser altimetry. The GIS continued to grow inland and thin at the margins during 2003 07, but surface melting and accelerated flow significantly increased the marginal thinning compared with the 1990s. The net balance changed from a small loss of 7 plus or minus 3 Gt a 1(sup -1) in the 1990s to 171 plus or minus 4 Gt a (sup -1) for 2003-07, contributing 0.5 mm a(sup -1) to recent global sea-level rise. We divide the derived mass changes into two components: (1) from changes in melting and ice dynamics and (2) from changes in precipitation and accumulation rate. We use our firn compaction model to calculate the elevation changes driven by changes in both temperature and accumulation rate and to calculate the appropriate density to convert the accumulation-driven changes to mass changes. Increased losses from melting and ice dynamics (17-206 Gt a(sup-1) are over seven times larger than increased gains from precipitation (10 35 Gt a(sup-1) during a warming period of approximately 2 K (10 a)(sup -1) over the GIS. Above 2000m elevation, the rate of gain decreased from 44 to 28 Gt a(sup-1), while below 2000m the rate of loss increased from 51 to 198 Gt a(sup-1). Enhanced thinning below the equilibrium line on outlet glaciers indicates that increased melting has a significant impact on outlet glaciers, as well as accelerating ice flow. Increased thinning at higher elevations appears to be induced by dynamic coupling to thinning at the margins on decadal timescales.

  8. Linking glacier annual mass balance and glacier albedo retrieved from MODIS data

    Directory of Open Access Journals (Sweden)

    M. Dumont

    2012-07-01

    Full Text Available Albedo is one of the variables controlling the mass balance of temperate glaciers. Multispectral imagers, such as MODerate Imaging Spectroradiometer (MODIS on board the TERRA and AQUA satellites, provide a means to monitor glacier surface albedo. In this study, different methods to retrieve broadband glacier surface albedo from MODIS data are compared. The effect of multiple reflections due to the rugged topography and of the anisotropic reflection of snow and ice are particularly investigated. The methods are tested on the Saint Sorlin Glacier (Grandes Rousses area, French Alps. The accuracy of the retrieved albedo is estimated using both field measurements, at two automatic weather stations located on the glacier, and albedo values derived from terrestrial photographs. For summers 2008 and 2009, the Root Mean Square Deviation (RMSD between field measurements and the broadband albedo retrieved from MODIS data at 250 m spatial resolution was found to be 0.052 or about 10% relative error. The RMSD estimated for the MOD10 daily albedo product is about three times higher. One decade (2000–2009 of MODIS data were then processed to create a time series of albedo maps of Saint Sorlin Glacier during the ablation season. The annual mass balance of Saint Sorlin Glacier was compared with the minimum albedo value (average over the whole glacier surface observed with MODIS during the ablation season. A strong linear correlation exists between the two variables. Furthermore, the date when the average albedo of the whole glacier reaches a minimum closely corresponds to the period when the snowline is located at its highest elevation, thus when the snowline is a good indicator of the glacier equilibrium line. This indicates that this strong correlation results from the fact that the minimal average albedo values of the glacier contains a considerable information regarding the relative share of areal surfaces between the ablation zone (i.e. ice with generally

  9. Recycled Uranium Mass Balance Project Y-12 National Security Complex Site Report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    This report has been prepared to summarize the findings of the Y-12 National Security Complex (Y-12 Complex) Mass Balance Project and to support preparation of associated U. S. Department of Energy (DOE) site reports. The project was conducted in support of DOE efforts to assess the potential for health and environmental issues resulting from the presence of transuranic (TRU) elements and fission products in recycled uranium (RU) processed by DOE and its predecessor agencies. The United States government used uranium in fission reactors to produce plutonium and tritium for nuclear weapons production. Because uranium was considered scarce relative to demand when these operations began almost 50 years ago, the spent fuel from U.S. fission reactors was processed to recover uranium for recycling. The estimated mass balance for highly enriched RU, which is of most concern for worker exposure and is the primary focus of this project, is summarized in a table. A discrepancy in the mass balance between receipts and shipments (plus inventory and waste) reflects an inability to precisely distinguish between RU and non-RU shipments and receipts involving the Y-12 Complex and Savannah River. Shipments of fresh fuel (non-RU) and sweetener (also non-RU) were made from the Y-12 Complex to Savannah River along with RU shipments. The only way to distinguish between these RU and non-RU streams using available records is by enrichment level. Shipments of {le}90% enrichment were assumed to be RU. Shipments of >90% enrichment were assumed to be non-RU fresh fuel or sweetener. This methodology using enrichment level to distinguish between RU and non-RU results in good estimates of RU flows that are reasonably consistent with Savannah River estimates. Although this is the best available means of distinguishing RU streams, this method does leave a difference of approximately 17.3 MTU between receipts and shipments. Slightly depleted RU streams received by the Y-12 Complex from ORGDP and

  10. Chemical mass balance source apportionment of fine and PM10 in the Desert Southwest, USA

    Directory of Open Access Journals (Sweden)

    Andrea L. Clements

    2016-03-01

    Full Text Available The Desert Southwest Coarse Particulate Matter Study was undertaken in Pinal County, Arizona, to better understand the origin and impact of sources of fine and coarse particulate matter (PM in rural, arid regions of the U.S. southwestern desert. The desert southwest experiences some of the highest PM10 mass concentrations in the country. To augment previously reported results, 6-week aggregated organic speciation data that included ambient concentrations of n-alkanes, polycyclic aromatic hydrocarbons, organic acids, and saccharides were used in chemical mass balance modeling (CMB. A set of re-suspended soil samples were analyzed for specific marker species to provide locally-appropriate source profiles for the CMB analysis. These profiles, as well as previously collected plant and fungal spore profiles from the region, were combined with published source profiles for other relevant sources and used in the CMB analysis. The six new region-specific source profiles included both organic and inorganic species for four crustal material sources, one plant detritus source, and one fungal spore source.Results indicate that up to half of the ambient PM2.5 was apportioned to motor vehicles with the highest regional contribution observed in the small urban center of Casa Grande. Daily levels of apportioned crustal material accounted for up to 50% of PM2.5 mass with the highest contributions observed at the sites closest to active agricultural areas. Apportioned secondary PM, biomass burning, and road dust typically contributed less than 35% as a group to the apportioned PM2.5 mass. Crustal material was the primary source apportioned to PM10 and accounted for between 50–90% of the apportioned mass. Of the other sources apportioned to PM10, motor vehicles and road dust were the largest contributors at the urban and one of the rural sites, whereas road dust and meat cooking operations were the largest contributors at the other rural site.

  11. The development of an efficient mass balance approach for the purity assignment of organic calibration standards.

    Science.gov (United States)

    Davies, Stephen R; Alamgir, Mahiuddin; Chan, Benjamin K H; Dang, Thao; Jones, Kai; Krishnaswami, Maya; Luo, Yawen; Mitchell, Peter S R; Moawad, Michael; Swan, Hilton; Tarrant, Greg J

    2015-10-01

    The purity determination of organic calibration standards using the traditional mass balance approach is described. Demonstrated examples highlight the potential for bias in each measurement and the need to implement an approach that provides a cross-check for each result, affording fit for purpose purity values in a timely and cost-effective manner. Chromatographic techniques such as gas chromatography with flame ionisation detection (GC-FID) and high-performance liquid chromatography with UV detection (HPLC-UV), combined with mass and NMR spectroscopy, provide a detailed impurity profile allowing an efficient conversion of chromatographic peak areas into relative mass fractions, generally avoiding the need to calibrate each impurity present. For samples analysed by GC-FID, a conservative measurement uncertainty budget is described, including a component to cover potential variations in the response of each unidentified impurity. An alternative approach is also detailed in which extensive purification eliminates the detector response factor issue, facilitating the certification of a super-pure calibration standard which can be used to quantify the main component in less-pure candidate materials. This latter approach is particularly useful when applying HPLC analysis with UV detection. Key to the success of this approach is the application of both qualitative and quantitative (1)H NMR spectroscopy. PMID:26342310

  12. Mass, energy, and exergy balance analysis of chemical looping with oxygen uncoupling (CLOU) process

    International Nuclear Information System (INIS)

    Highlights: • A CLOU reactor system using a CuO-based OC and coal as fuel is analyzed. • Possible operational regions for the chosen OC are identified. • Different heat balance scenarios are investigated. • The second-law efficiency of the system is evaluated. • Various design aspects and process modelling relationships are discussed. - Abstract: Chemical looping with oxygen uncoupling (CLOU) is a promising concept for efficient combustion of solid fuels with an inherent capture of the greenhouse gas CO2. This paper presents a CLOU process scheme with stoichiometric mass, energy, and exergy balances. A CLOU reactor system using medium volatile bituminous coal as fuel and silica-supported CuO as an oxygen carrier is analyzed. The analysis includes the estimation of various design and operational parameters, thermal considerations, and evaluation of the overall performance. The operation of a reactor system of two interacting circulating fluidized beds (CFBs) is greatly influenced by the hydrodynamics. For the CuO oxygen carrier, the hydrodynamic operating range appeared feasible considering the maximum solid circulation rates in current CFB boilers. Depending upon the reactor temperatures, oxygen carrier inventories of 400–680 kg/MW in the system were found necessary for stoichiometric combustion of the fuel. The temperature difference between the reactors should not exceed 50 °C, as otherwise, problems may arise with the heat balance. Exergetic efficiencies in the range of 63–70% were obtained for different combinations of relevant design parameters. It is evident that the possible operating conditions in the system are closely related to the properties of the chosen oxygen carrier. However, the calculation procedure and design criteria presented here are applicable to any oxygen carrier to be used in the process

  13. Cloud effects on the surface energy and mass balance of Brewster Glacier, New Zealand

    Directory of Open Access Journals (Sweden)

    J. P. Conway

    2015-02-01

    Full Text Available A thorough understanding of the influence of clouds on glacier surface energy balance (SEB and surface mass balance (SMB is critical for forward and backward modelling of glacier–climate interactions. A validated 22 month time series of SEB/SMB was constructed for the ablation zone of the Brewster Glacier, using high quality radiation data to carefully evaluate SEB terms and define clear-sky and overcast conditions. A fundamental change in glacier SEB in cloudy conditions was driven by increased effective sky emissivity and surface vapour pressure, rather than the minimal change in air temperature and wind speed. During overcast conditions, positive net longwave radiation and latent heat fluxes allowed melt to be maintained through a much greater length of time compared to clear-sky conditions, and led to similar melt in each sky condition. The sensitivity of SMB to changes in air temperature was greatly enhanced in overcast compared to clear-sky conditions due to more frequent melt and the occurrence of precipitation, which enabled a strong accumulation–albedo feedback. During the spring and autumn seasons, the sensitivity during overcast conditions was strongest. There is a need to include the effects of atmospheric moisture (vapour, cloud and precipitation on melt processes when modelling glacier–climate interactions.

  14. Effects of Extratropical Cyclone Frequency and Intensity on mass balance of the Greenland Ice Sheet

    Science.gov (United States)

    Auger, J.; Birkel, S. D.; Maasch, K. A.; Mayewski, P. A.

    2014-12-01

    Significant Arctic-wide warming over the past decade is thought to result in part from a weakening of the equator-pole thermal gradient in the atmosphere. Francis and Vavrus (2012) and others link Arctic amplification, or enhanced Arctic warming, to decreasing extratropical cyclone (ETC) speeds, and increasing northward meridional heat transports. Here, we are using the latest high-resolution reanalysis models (ASR, JRA-55, CFSR, ERA-Interim, MERRA) to evaluate how Arctic amplification may be impacting the mass balance of the Greenland Ice Sheet. Our approach is to assess synoptic-scale changes in circulation as represented by changes in storm tracks and storm intensities in the North Atlantic region. As part of this work, we are validating the reanalysis models against existing accumulation, ablation, and meteorological station data available across Greenland, and therefore hope to gain insights on model performance and applicability to the problem domain.

  15. BALANCE : a computer program for calculating mass transfer for geochemical reactions in ground water

    Science.gov (United States)

    Parkhurst, David L.; Plummer, L. Niel; Thorstenson, Donald C.

    1982-01-01

    BALANCE is a Fortran computer designed to define and quantify chemical reactions between ground water and minerals. Using (1) the chemical compositions of two waters along a flow path and (2) a set of mineral phases hypothesized to be the reactive constituents in the system, the program calculates the mass transfer (amounts of the phases entering or leaving the aqueous phase) necessary to account for the observed changes in composition between the two waters. Additional constraints can be included in the problem formulation to account for mixing of two end-member waters, redox reactions, and, in a simplified form, isotopic composition. The computer code and a description of the input necessary to run the program are presented. Three examples typical of ground-water systems are described. (USGS)

  16. A synthesis of the antarctic surface mass balance during the last eight centuries

    Directory of Open Access Journals (Sweden)

    M. Frezzotti

    2012-02-01

    Full Text Available Global climate models suggest that Antarctic snowfall should increase in a warming climate and mitigate sea level rise, mainly due to the greater moisture-holding capacity of the warmer atmosphere. Several processes act on snow accumulation or surface mass balance (SMB, introducing large uncertainties in the past, present, and future ice sheet mass balance. To provide an extended past perspective of the SMB of Antarctica, we used 66 firn/ice core records to reconstruct the temporal variability over the past eight centuries and in greater detail over the last two centuries. Our SMB reconstructions show that the changes over most of Antarctica are statistically negligible and the current SMB is not exceptionally high compared with the last eight centuries. However, a clear increase in accumulation of more than 10 % has occurred in high SMB coastal regions and over the highest part of the East Antarctic ice divide since 1960s. To explain the different behaviours between the coastal/ice divide sites and rest of Antarctica, we suggest that a higher frequency of blocking-anticyclones increases the precipitation at coastal sites, leading to the advection of moist air at the highest areas, whereas blowing snow and/or erosion have significant negative impacts on the SMB at windy sites. Eight centuries of SMB stacked records mirror the total solar irradiance, suggesting a link between the southern position of the Pacific Intertropical Convergence Zone and atmospheric circulation in Antarctica through the generation and propagation of a large-scale atmospheric wave train. Decadal records of the last eight centuries show that the observed increase in accumulation is not anomalous at the continental scale; indeed, high accumulation periods have also occurred in the past, during the 1370s and 1610s.

  17. Climatic Forcing of Glacier Surface Mass Balance Changes Along North-Central Peru: A Modeling Perspective

    Science.gov (United States)

    Mark, B. G.; Fernandez, A.

    2015-12-01

    Most tropical glaciers are Peru, where they are key water sources for communities in mountain environments and beyond. Thus, their sustained shrinkage portrays these glaciers as archetype of global warming impacts on the local scale. However, there is still no deep understanding on the mechanism connecting temperature and these glaciers. Among others, the effect of temperature on the glacier surface mass balance (GSMB) can be expressed within accumulation regimes and hence in surface albedo, or in ablation dynamics through incoming longwave energy (LE). Here, we report a study combining statistical analyses of reanalysis data (~30km grid-cell), regional climate modeling and glacier mass balance simulations at high resolution (2km) to analyze long-term (30 years) and seasonal GSMB along north-central Peru. Our goal is to mechanistically understand climate change impact on these glaciers. Results suggest temperature as the main factor controlling GSMB changes through the lapse rate (LR). Correlations of GSMB with LR, humidity and zonal wind point to vertical homogenization of temperature, causing LE to increase, despite this flux always remaining negative. This "less negative" LE multiplies the impact of the seasonal fluctuation in albedo, thereby enhancing total ablation. As this mechanism only needs a relative increase in temperature, it may even occur in subfreezing conditions. Model output also indicates that turbulent fluxes are small, largely cancelling out. This suggests that the impact of LE is more likely to occur compared to either turbulent fluxes changes or shifts in the proportion of sublimation versus melt, which we find to be regionally stable. These findings imply that glaciers in north-central Peru are sensitive to subtle changes in temperature. We discuss the implications for process-based understanding and how this non-linear and somewhat hidden effect of temperature reduces the skill of temperature index models to simulate GSMB in the Tropics.

  18. Occurrence, spatiotemporal distribution, mass balance and ecological risks of antibiotics in subtropical shallow Lake Taihu, China.

    Science.gov (United States)

    Zhou, Li-Jun; Wu, Qinglong L; Zhang, Bei-Bei; Zhao, Yong-Gang; Zhao, Bi-Ying

    2016-04-20

    The objective of this study was to evaluate the occurrence, spatiotemporal distribution, mass balance and ecological risks of 43 commonly used human and veterinary antibiotics in both aqueous and sedimentary phases in a large subtropical shallow lake, Lake Taihu. In the aqueous phase, sulfonamides (2.64-344 ng L(-1)), lincomycin (ND to 53.8 ng L(-1)) and florfenicol (0.15-963 ng L(-1)) were the main compounds with high concentrations and detection frequencies. In the sedimentary phase, fluoroquinolones (ND to 174 ng g(-1), dry weight) and tetracyclines (ND to 39.6 ng g(-1), dry weight) were the predominant compounds. Antibiotic concentrations in Lake Taihu were generally lower relative to data documented in previous studies on China and other countries. The composition of antibiotics showed that livestock wastewater might be the main source of antibiotics in Lake Taihu, followed by domestic wastewater. Antibiotics in the lake water showed slight spatial variation in summer and significant spatial variation in winter; whereas, antibiotic concentrations in the sediments varied obviously, with high concentrations found in the sites close to potential pollution sources. Mass balance showed that sediments are an important sink and potential source for fluoroquinolones and tetracyclines. In addition to antibiotics' physicochemical properties, the spatiotemporal distribution of antibiotics in the lake was influenced by both pollution sources and lake hydrodynamics. The environmental risk assessment results showed that sulfamethoxazole could pose high risks on the algae in the aquatic ecosystem, followed by tetracyclines (algae) and fluoroquinolones (bacteria). Overall, our study reveals complex compositions and clear spatiotemporal dynamics in Lake Taihu, which were the consequence of pollution sources and lake hydrodynamics. PMID:27048777

  19. Source identification and mass balance studies of mercury in Lake An-dong, S. Korea

    Science.gov (United States)

    Han, J.; Byeon, M.; Yoon, J.; Park, J.; Lee, M.; Huh, I.; Na, E.; Chung, D.; Shin, S.; Kim, Y.

    2009-12-01

    In this study, mercury and methylmercury were measured in atmospheric, tributary, open-lake water column, sediment, planktons and fish samples in the catchments area of Lake An-dong, S. Korea. Lake An-dong, an artificial freshwater lake is located on the upstream of River Nak-dong. It has 51.5 km2 of open surface water and 1.33 year of hydraulic residence time. It is a source of drinking water for 0.3 million S. Koreans. Recently, the possibilities of its mercury contamination became an issue since current studies showed that the lake had much higher mercury level in sediment and certain freshwater fish species than any other lakes in S. Korea. This catchments area has the possibilities of historical mercury pollution by the location of more than 50 abandoned gold mines and Young-poong zinc smelter. The objective of this study was to develop a mercury mass balance and identify possible mercury sources in the lake. The results of this study are thus expected to offer valuable insights for the sources of mercury loading through the watershed. In order to estimate the mercury flux, TGM, RGM and particulate mercury were measured using TEKRAN 2537 at the five sites surrounding Lake An-dong from May, 2009 with wet and dry deposition. The fate and transport of mercury in water body were predicted by using EFDC (Environmental Dynamic Fluid Code) and Mercury module in WASP7 (Water quality analysis program) after subsequent distribution into water body, sediments, followed by bioaccumulation and ultimate uptake by humans. The mercury mass balance in Young-poong zinc smelter was also pre-estimated by measuring mercury content in zinc ores, emission gases, sludge, wastewater and products.

  20. Multilevel spatiotemporal validation of snow/ice mass balance and runoff modeling in glacierized catchments

    Science.gov (United States)

    Hanzer, Florian; Helfricht, Kay; Marke, Thomas; Strasser, Ulrich

    2016-08-01

    In this study, the fully distributed, physically based hydroclimatological model AMUNDSEN is set up for catchments in the highly glacierized Ötztal Alps (Austria, 558 km2 in total). The model is applied for the period 1997-2013, using a spatial resolution of 50 m and a temporal resolution of 1 h. A novel parameterization for lateral snow redistribution based on topographic openness is presented to account for the highly heterogeneous snow accumulation patterns in the complex topography of the study region. Multilevel spatiotemporal validation is introduced as a systematic, independent, complete, and redundant validation procedure based on the observation scale of temporal and spatial support, spacing, and extent. This new approach is demonstrated using a comprehensive set of eight independent validation sources: (i) mean areal precipitation over the period 1997-2006 derived by conserving mass in the closure of the water balance, (ii) time series of snow depth recordings at the plot scale, (iii-iv) multitemporal snow extent maps derived from Landsat and MODIS satellite data products, (v) the snow accumulation distribution for the winter season 2010/2011 derived from airborne laser scanning data, (vi) specific surface mass balances for three glaciers in the study area, (vii) spatially distributed glacier surface elevation changes for the entire area over the period 1997-2006, and (viii) runoff recordings for several subcatchments. The results indicate a high overall model skill and especially demonstrate the benefit of the new validation approach. The method can serve as guideline for systematically validating the coupled components in integrated snow-hydrological and glacio-hydrological models.

  1. New considerations on the mass and energy balances in one-dimensional two-phase flow at steady state

    Energy Technology Data Exchange (ETDEWEB)

    Collado, F.J. [Zaragoza Univ. (Spain). Dept. de Ingenieria Mecanica; Munoz, M. [Zaragoza Univ. (Spain). Dept. de Ingenieria Mecanica

    1997-08-01

    A new equation to be added to the classical mass balance expressions for two-phase flow is presented. It is based on the definition of new differential control volumes of variable length which are proportional to the gas velocity in a compressible flow. The new equation is equivalent to the gas-solids velocity ratio being constant throughout the duct, and it is used to derive a new expression of the energy balance for a two-phase, non-reacting flow. Through this energy balance, new correlations for the pressure drop in pneumatic conveying lines are obtained, showing an excellent agreement with experimental data from the high-pressure research facility of the Institute of Gas Technology, Chicago, IL. Finally, a more general equation, which is also valid for the mass balance of reacting flows, is supplied. (orig.)

  2. Detailed comparison of the geodetic and direct glaciological mass balances on an annual time scale at Hintereisferner, Austria

    Science.gov (United States)

    Klug, Christoph; Bollmann, Erik; Galos, Stephan; Kaser, Georg; Prinz, Rainer; Rieg, Lorenzo; Sailer, Rudolf

    2016-04-01

    The quantification of glacier mass changes is fundamental for glacier monitoring and provides important information for climate change assessments, hydrological applications and sea-level changes. On Alpine glaciers two methods of measuring glacier mass changes are widely applied: the direct glaciological method and the geodetic method. Over the last decades several studies compared the mass balance estimates obtained by both methods to identify and correct stochastic and systematic errors. In almost all of these studies, the time span for comparison between the two methods is about one decade or longer. On Hintereisferner (HEF; Ötztal Alps, Austria) mass balance measurements were initiated in the glaciological year 1952/53, resulting in a consistent mass balance data set with an estimated accuracy of ±0.2 m w.e. a-1. Furthermore, 11 airborne laser scanning (ALS) campaigns were conducted between 2001 and 2011 at HEF, all consistent in accuracy as well as in precision (± 0.04 to 0.10 m for slopes ≤ 50°). This is a world-wide unique ALS dataset of a glacierized alpine catchment. Flight campaigns were performed close to the end of the hydrological year (30th September). Resulting data provide high quality topographic information to derive glacier mass changes by applying the geodetic method. On sub-decadal time-scales such method comparisons are rare, or reveal unexplainable large discrepancies between both mass balance methods. In this study we estimate stochastic and systematic uncertainties of the ALS data for processing volume changes, and quantify methodological differences, such as density assumptions, unequal measurement dates, crevasses and glacier dynamics. Hence, we present a method to compare direct glaciological and geodetic mass balances on an annual basis. In a first step, we calculate the annual geodetic mass balance of HEF between 2001 and 2011, resulting in a thickness change map of the glacier. In a second step, the snow cover, which has

  3. Overview and Assessment of Antarctic Ice-Sheet Mass Balance Estimates: 1992-2009

    Science.gov (United States)

    Zwally, H. Jay; Giovinetto, Mario B.

    2011-01-01

    Mass balance estimates for the Antarctic Ice Sheet (AIS) in the 2007 report by the Intergovernmental Panel on Climate Change and in more recent reports lie between approximately ?50 to -250 Gt/year for 1992 to 2009. The 300 Gt/year range is approximately 15% of the annual mass input and 0.8 mm/year Sea Level Equivalent (SLE). Two estimates from radar altimeter measurements of elevation change by European Remote-sensing Satellites (ERS) (?28 and -31 Gt/year) lie in the upper part, whereas estimates from the Input-minus-Output Method (IOM) and the Gravity Recovery and Climate Experiment (GRACE) lie in the lower part (-40 to -246 Gt/year). We compare the various estimates, discuss the methodology used, and critically assess the results. We also modify the IOM estimate using (1) an alternate extrapolation to estimate the discharge from the non-observed 15% of the periphery, and (2) substitution of input from a field data compilation for input from an atmospheric model in 6% of area. The modified IOM estimate reduces the loss from 136 Gt/year to 13 Gt/year. Two ERS-based estimates, the modified IOM, and a GRACE-based estimate for observations within 1992 2005 lie in a narrowed range of ?27 to -40 Gt/year, which is about 3% of the annual mass input and only 0.2 mm/year SLE. Our preferred estimate for 1992 2001 is -47 Gt/year for West Antarctica, ?16 Gt/year for East Antarctica, and -31 Gt/year overall (?0.1 mm/year SLE), not including part of the Antarctic Peninsula (1.07% of the AIS area). Although recent reports of large and increasing rates of mass loss with time from GRACE-based studies cite agreement with IOM results, our evaluation does not support that conclusion

  4. Re-assessment of recent (2008–2013 surface mass balance over Dome Argus, Antarctica

    Directory of Open Access Journals (Sweden)

    Minghu Ding

    2016-04-01

    Full Text Available At Dome Argus, East Antarctica, the surface mass balance (SMB from 2008 to 2013 was evaluated using 49 stakes installed across a 30×30 km area. Spatial analysis showed that at least 12 and 20 stakes are needed to obtain reliable estimates of SMB at local scales (a few hundred square metres and regional scales (tens of square kilometres, respectively. The estimated annual mean SMB was 22.9±5.9 kg m−2 yr−1, including a net loss by sublimation of −2.22±0.02 kg m−2 yr−1 and a mass gain by deposition of 1.37±0.01 kg m−2 yr−1. Therefore, ca. 14.3% of precipitation was modified after deposition, which should be considered when interpreting snow or ice core records produced by future drilling projects. The surface snow density and SMB in the western portion of Dome Argus are higher than in other areas, and these differences are likely related to the katabatic wind, which is strengthened by topography in this sector. A new digital elevation model (DEM of Dome Argus was generated, confirming that both peaks of the dome can be considered as the summit of the East Antarctic Ice Sheet. Findings from this study should be valuable for validating SMB estimates obtained from regional climate models and DEMs established using remote-sensing data.

  5. Glacier mass balance in high-arctic areas with anomalous gravity

    Science.gov (United States)

    Sharov, A.; Rieser, D.; Nikolskiy, D.

    2012-04-01

    All known glaciological models describing the evolution of Arctic land- and sea-ice masses in changing climate treat the Earth's gravity as horizontally constant, but it isn't. In the High Arctic, the strength of the gravitational field varies considerably across even short distances under the influence of a density gradient, and the magnitude of free air gravity anomalies attains 100 mGal and more. On long-term base, instantaneous deviations of gravity can have a noticeable effect on the regime and mass budget of glaciological objects. At best, the gravity-induced component of ice mass variations can be determined on topographically smooth, open and steady surfaces, like those of arctic planes, regular ice caps and landfast sea ice. The present research is devoted to studying gravity-driven impacts on glacier mass balance in the outer periphery of four Eurasian shelf seas with a very cold, dry climate and rather episodic character of winter precipitation. As main study objects we had chosen a dozen Russia's northernmost insular ice caps, tens to hundreds of square kilometres in extent, situated in a close vicinity of strong gravity anomalies and surrounded with extensive fields of fast and/or drift ice for most of the year. The supposition about gravitational forcing on glacioclimatic settings in the study region is based on the results of quantitative comparison and joint interpretation of existing glacier change maps and available data on the Arctic gravity field and solid precipitation. The overall mapping of medium-term (from decadal to half-centennial) changes in glacier volumes and quantification of mass balance characteristics in the study region was performed by comparing reference elevation models of study glaciers derived from Russian topographic maps 1:200,000 (CI = 20 or 40 m) representing the glacier state as in the 1950s-1980s with modern elevation data obtained from satellite radar interferometry and lidar altimetry. Free-air gravity anomalies were

  6. Freshwater mass balance and exchange of water masses with the open sea: the Mljet Lakes (Croatia, Adriatic Sea)

    Science.gov (United States)

    Martincic, Urska; Bezak, Nejc; Zagar, Dusan; Makovec, Tihomir; Lucic, Davor; Onofri, Vladimir; Malacic, Vlado

    2016-04-01

    Two karstic seawater lakes (Veliko - Big and Malo - Small Lake) located in the National Park Mljet on the Mljet Island in Croatia were investigated in this study. The Small and the Big Lake cover 0.25 and 1.45 km2, respectively. The two lakes are connected to each other and to the sea by narrow channels. The connecting channel between the Big Lake and the sea is 12 m wide and 3 m deep. The connection to the Small Lake leads through another artificial channel (2.7 m wide and 0.8 m deep). The average salinity of the Big and the Small lake is 37.75 and 36.9, respectively, and the average salinity of the open sea is 38.5. While previous studies have been conducted due to the lakes' unique ecosystem and the karstic characteristics of the area, the main aim of this study was to determine the freshwater mass balance and exchange of water masses with the nearby sea. Several measurement campaigns were performed between 2008 and 2015 when meteorological parameters as well as salinity, water temperature and water velocities in both lakes and the channels were observed. A perpetual year was determined using available meteorological data. The contribution of the surface runoff to both lakes was modelled using the hydrological rainfall-runoff HEC-HMS model. Curve number parameter was estimated using the CLC Corine Land cover and geomorphological maps. Evaporation from the lake was calculated using the Verburg, Kondo and Coare equations. We found that the annual evaporation approximately equals the annual rainfall to the lake surface (cca. 550-600 mm). From the hydrological model and the difference between precipitation and evaporation from the lake surface we calculated the annual net excess of freshwater between 0.5 106 and 0.7 106 m3. The average salinity in both lakes is lower than the salinity in the sea; therefore, we hypothesize that the excess water should be discharged either through the channel between the Big Lake and the open sea or through underwater karstic sink

  7. Mass, energy and material balances of SRF production process. Part 3: solid recovered fuel produced from municipal solid waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2015-02-01

    This is the third and final part of the three-part article written to describe the mass, energy and material balances of the solid recovered fuel production process produced from various types of waste streams through mechanical treatment. This article focused the production of solid recovered fuel from municipal solid waste. The stream of municipal solid waste used here as an input waste material to produce solid recovered fuel is energy waste collected from households of municipality. This article presents the mass, energy and material balances of the solid recovered fuel production process. These balances are based on the proximate as well as the ultimate analysis and the composition determination of various streams of material produced in a solid recovered fuel production plant. All the process streams are sampled and treated according to CEN standard methods for solid recovered fuel. The results of the mass balance of the solid recovered fuel production process showed that 72% of the input waste material was recovered in the form of solid recovered fuel; 2.6% as ferrous metal, 0.4% as non-ferrous metal, 11% was sorted as rejects material, 12% as fine faction and 2% as heavy fraction. The energy balance of the solid recovered fuel production process showed that 86% of the total input energy content of input waste material was recovered in the form of solid recovered fuel. The remaining percentage (14%) of the input energy was split into the streams of reject material, fine fraction and heavy fraction. The material balances of this process showed that mass fraction of paper and cardboard, plastic (soft) and wood recovered in the solid recovered fuel stream was 88%, 85% and 90%, respectively, of their input mass. A high mass fraction of rubber material, plastic (PVC-plastic) and inert (stone/rock and glass particles) was found in the reject material stream.

  8. Future projections of Greenland's ice loss accounting for changes in surface mass balance and dynamic discharge

    Science.gov (United States)

    Fürst, J. J.; Goelzer, H.; Huybrechts, P.

    2012-04-01

    Under future climate change, the Greenland Ice Sheet (GrIS) is highly vulnerable as its margins are relatively warm compared to Antarctica making them relatively prone for summer melting. A rise of about three degrees in annual average temperature over Greenland is expected to lead to irreversible ice sheet melting, which makes the GrIS a sensitive element in the Earth's climate system. Moreover, extended coverage and improved observation techniques have revealed high variations in dynamical ice discharge from outlet glaciers around the entire ice sheet. During the last decade, this dynamic discharge has contributed to almost half of the total mass loss. Since variations of the dynamic discharge are limited to the GrIS margin, direct inland transmission of these perturbations is necessary to significantly alter the overall GIS evolution on short time scales. Gradients in membrane stresses hold the potential for direct horizontal coupling and thus concerns are raised whether direct signal transmission has a significant impact on the ice interior. Because of strong mutual feedbacks between surface mass balance and marginal ice dynamics, our aim is to account for changes in both to assess the future GrIS contribution to sea level rise. For this purpose, we use a three-dimensional ice sheet model with a Blatter/Pattyn dynamic core that allows for direct signal transmission in ice flow. The surface mass balance is calculated by a positive degree-day model, which accounts for internal accumulation and temporary water storage in the snow cover. The model is initialised by calibrating a glacial cycle spin-up to the present day geometry. For the last half of the 20th century we force the ice sheet model with reanalysis data of surface temperature and precipitation. Future climate scenarios are taken from general circulation models and used in anomaly mode in the positive degree-day model. These scenarios are based on the representative concentration pathways that were

  9. Reconstruction of Glacier Mass Balance and Sensitivity Tests to Climate Change: A case study of Ålfotbreen and Nigardsbreen

    OpenAIRE

    Wangdui, Wangdui

    2011-01-01

    A physically-based one dimensional CROCUS snow model was applied to simulate the surface mass balances of Ålfotbreen (1964-2009) and Nigardsbreen (1962-2009) in southern Norway. The required hourly meteorological input data (9 parameters) are obtained from daily data of meteorological observation from stations surrounding the glaciers combined with NCEP 6 hourly reanalysis data to get the diurnal cycle. The results of simulations show that the model was able to simulate the mass balance of Ål...

  10. Mass Balance Modeling for Electric Arc Furnace and Ladle Furnace System in Steelmaking Facility in Turkey

    Institute of Scientific and Technical Information of China (English)

    (I)smail Ekmek(c)i; Ya(s)ar Yetisken; (U)nal (C)amdali

    2007-01-01

    In the electric arc furnace (EAF) steel production processes, scrap steel is principally used as a raw material instead of iron ore. In the steelmaking process with EAF, scrap is first melted in the furnace and then the desired chemical composition of the steel can be obtained in a special furnace such as ladle furnace (LF). This kind of furnace process is used for the secondary refining of alloy steel. LF furnace offers strong heating fluxes and enables precise temperature control, thereby allowing for the addition of desired amounts of various alloying elements. It also provides outstanding desulfurization at high-temperature treatment by reducing molten steel fluxes and removing deoxidation products. Elemental analysis with mass balance modeling is important to know the precise amount of required alloys for the LF input with respect to scrap composition. In present study, chemical reactions with mass conservation law in EAF and LF were modeled altogether as a whole system and chemical compositions of the final steel alloy output can be obtained precisely according to different scrap compositions, alloying elements ratios, and other input amounts. Besides, it was found that the mass efficiency for iron element in the system is 95.93%. These efficiencies are calculated for all input elements as 8.45% for C, 30.31% for Si, 46.36% for Mn, 30.64% for P, 41.96% for S, and 69.79% for Cr, etc. These efficiencies provide valuable ideas about the amount of the input materials that are vanished or combusted for 100 kg of each of the input materials in the EAF and LF system.

  11. Assessment of Antarctic Ice-Sheet Mass Balance Estimates: 1992 - 2009

    Science.gov (United States)

    Zwally, H. Jay; Giovinetto, Mario B.

    2011-01-01

    Published mass balance estimates for the Antarctic Ice Sheet (AIS) lie between approximately +50 to -250 Gt/year for 1992 to 2009, which span a range equivalent to 15% of the annual mass input and 0.8 mm/year Sea Level Equivalent (SLE). Two estimates from radar-altimeter measurements of elevation change by European Remote-sensing Satellites (ERS) (+28 and -31 Gt/year) lie in the upper part, whereas estimates from the Input-minus-Output Method (IOM) and the Gravity Recovery and Climate Experiment (GRACE) lie in the lower part (-40 to -246 Gt/year). We compare the various estimates, discuss the methodology used, and critically assess the results. Although recent reports of large and accelerating rates of mass loss from GRACE=based studies cite agreement with IOM results, our evaluation does not support that conclusion. We find that the extrapolation used in the published IOM estimates for the 15 % of the periphery for which discharge velocities are not observed gives twice the rate of discharge per unit of associated ice-sheet area than the 85% faster-moving parts. Our calculations show that the published extrapolation overestimates the ice discharge by 282 Gt/yr compared to our assumption that the slower moving areas have 70% as much discharge per area as the faster moving parts. Also, published data on the time-series of discharge velocities and accumulation/precipitation do not support mass output increases or input decreases with time, respectively. Our modified IOM estimate, using the 70% discharge assumption and substituting input from a field-data compilation for input from an atmospheric model over 6% of area, gives a loss of only 13 Gt/year (versus 136 Gt/year) for the period around 2000. Two ERS-based estimates, our modified IOM, and a GRACE-based estimate for observations within 1992 to 2005 lie in a narrowed range of +27 to - 40 Gt/year, which is about 3% of the annual mass input and only 0.2 mm/year SLE. Our preferred estimate for 1992-2001 is - 47 Gt

  12. Mass, energy and material balances of SRF production process. Part 2: SRF produced from construction and demolition waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2014-11-01

    In this work, the fraction of construction and demolition waste (C&D waste) complicated and economically not feasible to sort out for recycling purposes is used to produce solid recovered fuel (SRF) through mechanical treatment (MT). The paper presents the mass, energy and material balances of this SRF production process. All the process streams (input and output) produced in MT waste sorting plant to produce SRF from C&D waste are sampled and treated according to CEN standard methods for SRF. Proximate and ultimate analysis of these streams is performed and their composition is determined. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. By mass balance means the overall mass flow of input waste material stream in the various output streams and material balances mean the mass flow of components of input waste material stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. The results from mass balance of SRF production process showed that of the total input C&D waste material to MT waste sorting plant, 44% was recovered in the form of SRF, 5% as ferrous metal, 1% as non-ferrous metal, and 28% was sorted out as fine fraction, 18% as reject material and 4% as heavy fraction. The energy balance of this SRF production process showed that of the total input energy content of C&D waste material to MT waste sorting plant, 74% was recovered in the form of SRF, 16% belonged to the reject material and rest 10% belonged to the streams of fine fraction and heavy fraction. From the material balances of this process, mass fractions of plastic (soft), paper and cardboard, wood and plastic (hard) recovered in the SRF stream were 84%, 82%, 72% and 68% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC) and rubber material was found in the reject material

  13. Mass, energy and material balances of SRF production process. Part 1: SRF produced from commercial and industrial waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2014-08-01

    This paper presents the mass, energy and material balances of a solid recovered fuel (SRF) production process. The SRF is produced from commercial and industrial waste (C&IW) through mechanical treatment (MT). In this work various streams of material produced in SRF production process are analyzed for their proximate and ultimate analysis. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. Here mass balance describes the overall mass flow of input waste material in the various output streams, whereas material balance describes the mass flow of components of input waste stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. A commercial scale experimental campaign was conducted on an MT waste sorting plant to produce SRF from C&IW. All the process streams (input and output) produced in this MT plant were sampled and treated according to the CEN standard methods for SRF: EN 15442 and EN 15443. The results from the mass balance of SRF production process showed that of the total input C&IW material to MT waste sorting plant, 62% was recovered in the form of SRF, 4% as ferrous metal, 1% as non-ferrous metal and 21% was sorted out as reject material, 11.6% as fine fraction, and 0.4% as heavy fraction. The energy flow balance in various process streams of this SRF production process showed that of the total input energy content of C&IW to MT plant, 75% energy was recovered in the form of SRF, 20% belonged to the reject material stream and rest 5% belonged with the streams of fine fraction and heavy fraction. In the material balances, mass fractions of plastic (soft), plastic (hard), paper and cardboard and wood recovered in the SRF stream were 88%, 70%, 72% and 60% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC), rubber material and non

  14. Mass and Energy Balances for Black Liquor Gasification with Borate Autocausticization

    Energy Technology Data Exchange (ETDEWEB)

    Arosenius, Anna-Karin

    2007-01-15

    Gasification of black liquor is considered to be a promising alternative technique for recovery of black liquor in kraft pulping. Compared to the conventional recovery process, i.e. combustion of black liquor in a recovery boiler, the primary advantage of gasification is the potential to produce biofuels and chemicals. The causticizing demand is though higher for the gasification technology. If the existing lime kiln can not handle the extra load, partial borate autocausticizing may be an alternative. In this work, the energy balance for a kraft pulp mill using black liquor gasification and partial borate autocausticization is compared with a mill using gasification and extended lime causticizing and also with a mill having a conventional recovery cycle. Additionally, the chemical costs for the partial borate autocausticizing is compared to the investment cost of the larger lime kiln. Mass and energy balances are based on the updated reference mill in the MISTRA Research Program, 'The Eco-Cyclic Pulp Mill', producing 2000 ADt of pulp per day. The results show that less energy is released to steam production in a gasifier than in a recovery boiler and instead energy is released in chemical form in the produced syn gas. Using partial borate autocausticizing, the demand of external energy is lowered in the lime kiln compared to extended lime causticization. The borate autocausticization, taking place in the gasifier with black liquor as energy source, only demands a third of the energy saved in the lime kiln. On the other hand the chemical costs for the borate autocausticization exceeds the investment cost for a larger lime kiln after five years.

  15. Mass Balance of Arctic Sea Ice North of Svalbard during N-ICE2015

    Science.gov (United States)

    Rösel, A.; Gerland, S.; King, J.; Itkin, P.

    2015-12-01

    The N-ICE2015 cruise, led by the Norwegian Polar Institute, was a drift experiment with the research vessel R/V Lancefrom January to June 2015, where the ship started the drift North of Svalbard at 83°14.45' N, 21°31.41' E. The drift was repeated as soon as the vessel drifted free. Altogether during the 6 month, 4 ice stations where installed and the complex ocean-sea ice-atmosphere system was studied with an interdisciplinary approach. During the N-ICE2015 cruise, extensive ice thickness and snow depth measurements were performed during both, winter and summer conditions. Total ice and snow thickness was measured with ground-based and airborne electromagnetic instruments like EM31, GEM, and EM-bird; snow depth was measured with a GPS snow depth probe. Additionally, ice mass balance and snow buoys were deployed. Snow and ice thickness measurements were performed on repeated transects to quantify the ice growth or loss as well as the snow accumulation and melt rate. Additionally, we collected independent values on surveys to determine the general ice thickness distribution. In terms of mass balance, average snow depths of 32 cm on first year ice, and 52 cm on multiyear ice were measured in January, the mean snow depth on all ice types even increased until end of March to 49 cm. The average total ice and snow thickness in winter conditions was 1.92 cm. During winter, we found an unusual small growth rate on multiyear ice of about 15 cm in 2 months, due to above-average snow depths and some extraordanary storm events that came along with mild temperatures. In contrast thereto, we were also able to study new ice formation and thin ice on refrozen leads. In summer conditions an enormous melt rate, mainly driven by a warm Atlantic water inflow in the marginal ice zone, was observed during two ice stations with melt rates of up to 20 cm per 24 hours. The here presented dataset is a mandatory parameter for understanding the ocean-ice-atmosphere interactions, for

  16. Mass balance of the Greenland ice sheet – a study of ICESat data, surface density and firn compaction modelling

    Directory of Open Access Journals (Sweden)

    L. S. Sørensen

    2010-10-01

    Full Text Available ICESat has provided surface elevation measurements of the ice sheets since the launch in January 2003, resulting in a unique data set for monitoring the changes of the cryosphere. Here we present a novel method for determining the mass balance of the Greenland ice sheet derived from ICESat altimetry data.

    Four different methods for deriving the elevation changes from the ICESat altimetry data set are used. This multi method approach gives an understanding of the complexity associated with deriving elevation changes from the ICESat altimetry data set.

    The altimetry can not stand alone in estimating the mass balance of the Greenland ice sheet. We find firn dynamics and surface densities to be important factors in deriving the mass loss from remote sensing altimetry. The volume change derived from ICESat data is corrected for firn compaction, vertical bedrock movement and an intercampaign elevation bias in the ICESat data. Subsequently, the corrected volume change is converted into mass change by surface density modelling. The firn compaction and density models are driven by a dynamically downscaled simulation of the HIRHAM5 regional climate model using ERA-Interim reanalysis lateral boundary conditions.

    We find an annual mass loss of the Greenland ice sheet of 210 ± 21 Gt yr−1 in the period from October 2003 to March 2008. This result is in good agreement with other studies of the Greenland ice sheet mass balance, based on different remote sensing techniques.

  17. Lake Michigan Mass Balance Study Post Audit: Integrated, Multi-media PCB Modeling and Forecasting for Lake Trout

    Science.gov (United States)

    The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

  18. SOURCE APPORTIONMENT OF PM 2.5 AND CARBON IN SEATTLE USING CHEMICAL MASS BALANCE AND POSITIVE MATRIX FACTORIZATION

    Science.gov (United States)

    Three years of PM2.5 speciated data were collected and chemically analyzed using the IMPROVE protocol at the Beacon Hill site in Seattle. The data were analyzed by the Chemical Mass Balance Version 8 (CMB8) and Positive Matrix Factorization (PMF) source apportionment models. T...

  19. Contemporary (1960–2012) Evolution of the Climate and Surface Mass Balance of the Greenland Ice Sheet

    NARCIS (Netherlands)

    van Angelen, J. H.; van den Broeke, M. R.; Wouters, B.; Lenaerts, J. T M

    2013-01-01

    We assess the contemporary (1960–2012) surface mass balance (SMB) of the Greenland ice sheet (GrIS), its individual components and trends. We use output of the high-resolution (11 km) regional atmospheric climate model (RACMO2), evaluated with automatic weather stations and GRACE data. A persistent

  20. A Simplified Model of Human Alcohol Metabolism That Integrates Biotechnology and Human Health into a Mass Balance Team Project

    Science.gov (United States)

    Yang, Allen H. J.; Dimiduk, Kathryn; Daniel, Susan

    2011-01-01

    We present a simplified human alcohol metabolism model for a mass balance team project. Students explore aspects of engineering in biotechnology: designing/modeling biological systems, testing the design/model, evaluating new conditions, and exploring cutting-edge "lab-on-a-chip" research. This project highlights chemical engineering's impact on…

  1. Process monitoring and modeling of a continuous pharmaceutical from powder to tablet process Line using a mass & energy balance

    DEFF Research Database (Denmark)

    Beer, Thomas De; Mortier, Séverine Thérèse F.C.; Gernaey, Krist;

    2014-01-01

    The intention to shift from batch to continuous production processes within the pharmaceutical industry enhances the need to monitor and control the process in-line and real-time to continuously guarantee the end-product quality. Mass and energy balances have been successfully applied to a drying...

  2. On the importance of sublimation to an alpine snow mass balance in the Canadian Rocky Mountains

    Directory of Open Access Journals (Sweden)

    M. K. MacDonald

    2010-07-01

    Full Text Available A modelling study was undertaken to evaluate the contribution of sublimation to an alpine snow mass balance in the Canadian Rocky Mountains. Snow redistribution and sublimation by wind, snowpack sublimation and snowmelt were simulated for two winters over an alpine ridge transect located in the Canada Rocky Mountains. The resulting snowcover regimes were compared to those from manual snow surveys. Simulations were performed using physically based blowing snow (PBSM and snowpack ablation (SNOBAL models. A hydrological response unit (HRU-based spatial discretization was used rather than a more computationally expensive fully-distributed one. The HRUs were set up to follow an aerodynamic sequence, whereby eroded snow was transported from windswept, upwind HRUs to drift accumulating, downwind HRUs. That snow redistribution by wind can be adequately simulated in computationally efficient HRUs over this ridge has important implications for representing snow transport in large-scale hydrology models and land surface schemes. Alpine snow sublimation losses, in particular blowing snow sublimation losses, were significant. Snow mass losses to sublimation as a percentage of cumulative snowfall were estimated to be 20–32% with the blowing snow sublimation loss amounting to 17–19% of cumulative snowfall. This estimate is considered to be a conservative estimate of the blowing snow sublimation loss in the Canadian Rocky Mountains because the study transect is located in the low alpine zone where the topography is more moderate than the high alpine zone and windflow separation was not observed. An examination of the suitability of PBSM's sublimation estimates in this environment and of the importance of estimating blowing snow sublimation on the simulated snow accumulation regime was conducted by omitting sublimation calculations. Snow accumulation in HRUs was overestimated by 30% when neglecting blowing snow sublimation calculations.

  3. Effect of enhanced manganese oxidation in the hyporheic zone on basin-scale geochemical mass balance

    Science.gov (United States)

    Harvey, J.W.; Fuller, C.C.

    1998-01-01

    cumulative effect of hyporheic exchange in Pinal Creek basin was to remove approximately 20% of the dissolved manganese flowing out of the drainage basin. Our results illustrate that the cumulative significance of reactive uptake in the hyporheic zone depends on the balance between chemical reaction rates, hyporheic porewater residence time, and turnover of streamflow through hyporheic flow paths. The similarity between the hyporheic reaction timescale (1??(s) ??? 1.3 hours), and the hyporheic porewater residence timescale (t(s) ??? 8 min) ensured that there was adequate time for the reaction to progress. Furthermore, it was the similarity between the turnover length for stream water flow through hyporheic flow paths (L(s) = stream velocity/storage-zone exchange coefficient ??? 1.3 km) and the length of Pinal Creek (L ??? 7 km), which ensured that all stream water passed through hyporheic flow paths several times. As a means to generalize our findings to other sites where similar types of hydrologic and chemical information are available, we suggest a cumulative significance index for hyporheic reactions, R(s) = ??(s)t(s)L/L(s) (dimensionless); higher values indicate a greater potential for hyporheic reactions to influence geochemical mass balance. Our experience in Pinal Creek basin suggests that values of R(s) > 0.2 characterize systems where hyporheic reactions are likely to influence geochemical mass balance at the drainage-basin scale.

  4. Aquatic worms eat sludge: Mass balances and processing of worm faeces

    International Nuclear Information System (INIS)

    Reduction of the amount of waste sludge from waste water treatment plants (WWTPs) can be achieved with the aquatic worm Lumbriculus variegatus in a new reactor concept. In addition to reducing the amount of waste sludge, further processing of produced worm faeces and released nutrients should also be considered. This study gives the mass balances for sludge consumed by L. variegatus, showing the fate of the consumed organic material, nutrients and heavy metals associated with the sludge. A distinction is made between conversion into worm biomass, release as dissolved metabolites and what remains in the worm faeces. The results showed that 39% of the nitrogen and 12% of the phosphorus in the sludge digested by the worms are used in the formation of new worm biomass, which has potential for reuse. Experiments showed that settling of the worm faeces leads to a factor 2.5 higher solids concentration, compared to settling of waste sludge. This could lead to a 67% reduction of the volumetric load on thickening equipment. The worm reactor is expected to be most interesting for smaller WWTPs where a decrease on the volumetric load on sludge handling operations will have most impact.

  5. A mass balance approach to assess carbon dioxide evolution during erosional events

    International Nuclear Information System (INIS)

    The accelerated greenhouse effect and the degradation of land resources by water and wind erosion are two major, yet interrelated global environmental challenges. Accelerated decomposition of soil organic carbon (SOC) in cultivated soils results in decline in SOC stocks over time and also contributes to increased levels of CO2 in the atmosphere. Off-site transport of SOC in runoff waters during erosional events also contributes to SOC depletion, but there is a paucity of data in the literature documenting erosional SOC losses and the fate of eroded SOC. In this paper, we present a mass balance approach to compute CO2 evolved from mineralization of SOC during transport and deposition of eroded soils. Erosion-induced CO2 emission rates ranging between 6 and 52 g C m-2 yr-1 were computed using data on SOC stocks and dynamics from a series of long-term experiments conducted across a range of ecological regions. For the cropland of the world, we estimated an annual flux of 0.37 Pg CO2 -C to the atmosphere due to water erosion. This flux is significant and suggests that water erosion must be taken into consideration when constructing global and regional C budgets. Through its contribution to atmospheric CO2 increase, water erosion can have a positive feedback on the accelerated greenhouse effect. (author)

  6. Characterization and mass balance of trace elements in an iron ore sinter plant

    Directory of Open Access Journals (Sweden)

    Lucas Ladeira Lau

    2016-04-01

    Full Text Available Environmental legislation is becoming more restrictive in several industrial sectors, especially in the steel industry, which is well known for its large pollution potential. With the recent growth of interest in effects of trace elements on the environment and health, the inclusion of emission limits on these elements in this legislation has become increasingly popular. This article aims to describe the partitioning of trace elements between the products (sinter and plant emissions in an iron ore sinter plant, aiming to better understand the behavior of these elements in the sintering process to eventually support interventions to modify these partitions. Chemical characterization of several sintering inputs was initially performed, revealing that the steel-making residues contained large concentrations of trace elements, whereas low concentrations were observed in the flux. Based on the trace element concentrations, we analyzed the injection of trace elements in a sintering pilot using a sintering mixture. Mass balance was then used to determine the theoretical partitioning of trace elements in the sinter and emissions; cadmium, nickel, lead, mercury, and copper exhibited greater tendencies to concentrate in atmospheric emissions.

  7. Mass and Energy Balances of Dry Thermophilic Anaerobic Digestion Treating Swine Manure Mixed with Rice Straw

    Directory of Open Access Journals (Sweden)

    Sheng Zhou

    2015-01-01

    Full Text Available To evaluate the feasibility of swine manure treatment by a proposed Dry Thermophilic Anaerobic Digestion (DT-AD system, we evaluated the methane yield of swine manure treated using a DT-AD method with rice straw under different C/N ratios and solid retention time (SRT and calculated the mass and energy balances when the DT-AD system is used for swine manure treatment from a model farm with 1000 pigs and the digested residue is used for forage rice production. A traditional swine manure treatment Oxidation Ditch system was used as the study control. The results suggest that methane yield using the proposed DT-AD system increased with a higher C/N ratio and shorter SRT. Correspondently, for the DT-AD system running with SRT of 80 days, the net energy yields for all treatments were negative, due to low biogas production and high heat loss of digestion tank. However, the biogas yield increased when the SRT was shortened to 40 days, and the generated energy was greater than consumed energy when C/N ratio was 20:1 and 30:1. The results suggest that with the correct optimization of C/N ratio and SRT, the proposed DT-AD system, followed by using digestate for forage rice production, can attain energy self-sufficiency.

  8. Stable climate and surface mass balance in Svalbard over 1979–2013 despite the Arctic warming

    Directory of Open Access Journals (Sweden)

    C. Lang

    2014-08-01

    Full Text Available With the help of the regional climate model MAR forced by the ERA-Interim reanalysis (MARERA and the MIROC5 global model (MARMIROC5 from the CMIP5 database, we have modelled the climate and surface mass balance of Svalbard at a 10 km resolution over 1979–2013. The integrated total SMB over Svalbard modelled by MARERA is negative (−1.6 Gt yr−1 with a large interannual variability (7.1 Gt but, unlike over Greenland, there has been no acceleration of the surface melt over the past 35 years because of the recent change in atmospheric circulation bringing northerly flows in summer over Svalbard, contrasting the recent observed Arctic warming. However, in 2013, the atmospheric circulation changed to a southwesterly flow over Svalbard causing a record of melt, SMB (−20.4 Gt yr−1 and summer temperature. MIROC5 is significantly colder than ERA-Interim over 1980–2005 but MARMIROC5 is able to improve the near-surface MIROC5 results by simulating not significant SMB differences with MARERA over 1980–2005. On the other hand, MIROC5 does not represent the recent atmospheric circulation shift in summer and induces in MARMIROC5 a significant trend of decreasing SMB (−0.6 Gt yr−2 over 1980–2005.

  9. An updated and quality controlled surface mass balance dataset for Antarctica

    Directory of Open Access Journals (Sweden)

    V. Favier

    2012-09-01

    Full Text Available We present an updated and quality controlled surface mass balance (SMB database for the Antarctic ice sheet. We retrieved a total of 5284 SMB data documented with important meta-data, to which a filter was applied to discard data with limited spatial and temporal representativeness, too small measurement accuracy, or lack of quality control. A total of 3438 reliable data was obtained, which is about four times more than by applying the same data filtering process to previously available databases. New important data with high spatial resolution are now available over long traverses, and at low elevation in some areas. However, the quality control led to a considerable reduction in the spatial density of data in several regions, particularly over West Antarctica. Over interior plateaus, where the SMB is low, the spatial density of measurements remained high. This quality controlled dataset was compared to results from ERA-Interim reanalysis to assess model representativeness over Antarctica, and also to identify large areas where data gaps impede model validation. Except for very few areas (e.g. Adelie Land, the elevation range between 200 m and 1000 m a.s.l. is not correctly sampled in the field, and measurements do not allow a thorough validation of models in regions with complex topography, where the highest scattering of SMB values is reported. Clearly, increasing the spatial density of field measurements at low elevations, in the Antarctic Peninsula and in West Antarctica remains a scientific priority.

  10. Nitrogen losses from dairy manure estimated through nitrogen mass balance and chemical markers

    Science.gov (United States)

    Hristov, Alexander N.; Zaman, S.; Vander Pol, M.; Ndegwa, P.; Campbell, L.; Silva, S.

    2009-01-01

    Ammonia is an important air and water pollutant, but the spatial variation in its concentrations presents technical difficulties in accurate determination of ammonia emissions from animal feeding operations. The objectives of this study were to investigate the relationship between ammonia volatilization and ??15N of dairy manure and the feasibility of estimating ammonia losses from a dairy facility using chemical markers. In Exp. 1, the N/P ratio in manure decreased by 30% in 14 d as cumulative ammonia losses increased exponentially. Delta 15N of manure increased throughout the course of the experiment and ??15N of emitted ammonia increased (p mass balance approach, approximately half of the N excreted by dairy cows (Bos taurus) could not be accounted for in 24 h. Using N/P and N/K ratios in fresh and 24-h manure, an estimated 0.55 and 0.34 (respectively) of the N excreted with feces and urine could not be accounted for. This study demonstrated that chemical markers (P, K) can be successfully used to estimate ammonia losses from cattle manure. The relationship between manure ??15N and cumulative ammonia loss may also be useful for estimating ammonia losses. Although promising, the latter approach needs to be further studied and verified in various experimental conditions and in the field. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  11. Basin Excavation, Lower Crust, Composition, and Bulk Moon Mass balance in Light of a Thin Crust

    Science.gov (United States)

    Jolliff, B. L.; Korotev, R. L.; Ziegler, R. A.

    2013-01-01

    New lunar gravity results from GRAIL have been interpreted to reflect an overall thin and low-density lunar crust. Accordingly, crustal thickness has been modeled as ranging from 0 to 60 km, with thinnest crust at the locations of Crisium and Moscoviense basins and thickest crust in the central farside highlands. The thin crust has cosmochemical significance, namely in terms of implications for the Moon s bulk composition, especially refractory lithophile elements that are strongly concentrated in the crust. Wieczorek et al. concluded that the bulk Moon need not be enriched compared to Earth in refractory lithophile elements such as Al. Less Al in the crust means less Al has been extracted from the mantle, permitting relatively low bulk lunar mantle Al contents and low pre- and post-crust-extraction values for the mantle (or the upper mantle if only the upper mantle underwent LMO melting). Simple mass-balance calculations using the method of [4] suggests that the same conclusion might hold for Th and the entire suite of refractory lithophile elements that are incompatible in olivine and pyroxene, including the KREEP elements, that are likewise concentrated in the crust.

  12. A heuristic simulation model of Lake Ontario circulation and mass balance transport

    Science.gov (United States)

    McKenna, J.E., Jr.; Chalupnicki, M.A.

    2011-01-01

    The redistribution of suspended organisms and materials by large-scale currents is part of natural ecological processes in large aquatic systems but can contribute to ecosystem disruption when exotic elements are introduced into the system. Toxic compounds and planktonic organisms spend various lengths of time in suspension before settling to the bottom or otherwise being removed. We constructed a simple physical simulation model, including the influence of major tributaries, to qualitatively examine circulation patterns in Lake Ontario. We used a simple mass balance approach to estimate the relative water input to and export from each of 10 depth regime-specific compartments (nearshore vs. offshore) comprising Lake Ontario. Despite its simplicity, our model produced circulation patterns similar to those reported by more complex studies in the literature. A three-gyre pattern, with the classic large counterclockwise central lake circulation, and a simpler two-gyre system were both observed. These qualitative simulations indicate little offshore transport along the south shore, except near the mouths of the Niagara River and Oswego River. Complex flow structure was evident, particularly near the Niagara River mouth and in offshore waters of the eastern basin. Average Lake Ontario residence time is 8 years, but the fastest model pathway indicated potential transport of plankton through the lake in as little as 60 days. This simulation illustrates potential invasion pathways and provides rough estimates of planktonic larval dispersal or chemical transport among nearshore and offshore areas of Lake Ontario. ?? 2011 Taylor & Francis.

  13. Primary Pollutants Monitoring and Modeling Using Chemical Mass Balance (CMB Around Fahaheel Residential Area

    Directory of Open Access Journals (Sweden)

    S. M. Al-Salem

    2008-01-01

    Full Text Available Four major sources of air pollution were identified and modeled using Chemical Mass Balance (CMB around a residential area. The sources were identified as MAA refinery, downtown area, upstream facilities and main highway road. The sources were analyzed using a series of concentration roses (unfiltered and filtered executed from the data collected. Data collected included primary and secondary pollutants levels as well as major metrological parameters. The model gave a 91% and 89% match at the receptor point for the identified sources in two different durations. Metrological conditions and chemical fingerprints were adapted into the model to minimize the error and mismatch. Seasonal variation analysis was established by choosing the two months that represent the seasonal distribution in the year. Local and international rules and regulations were cross referenced in order to evaluate the air quality of the area under investigation. A number of violations in terms of ambient levels of primary and secondary pollutants were found and reported in this study.

  14. Mass, energy, entropy and exergy rate balance in a ranque-hilsh vortex tube

    Directory of Open Access Journals (Sweden)

    Edorta Carrascal

    2013-12-01

    Full Text Available The purpose of this paper is to exhibit a laboratory practicum designed for the subject of Thermodynamics at the Department of Thermal Engineering of the University of the Basque Country. With reference to one of the problems stated in the text of Moran, Shapiro, Boettner, Bailey (2012, the balances of mass, energy, entropy and exergy are applied in a particular Control Volume, and the ideal gas model is used. Using a Ranque-Hilsh vortex tube (Ranque, 1934, the division of a compressed air flow into two streams at a lower pressure is achieved; one hot  whose temperature can exceed 100 °C and another cold that can reach temperatures below -40 °C. Therefore an air flow is divided into two, one hot and one cold stream, without any thermal interaction with hot or cold focuses. The vortex tube operation can serve to expose the bases of the first and second law of thermodynamics. Even, this practical lab can be used to give sense to one of the most known theoretical experiments in thermodynamics, such as the one of Maxwell's demon (Lewins & Bejan, 1999; Liew, Zeegers, Kuerten & Michalek, 2012. On the other hand once a compressed air source is provided, the material needed to prepare the lab is simple and affordable and it has a very interesting and suggestive appeal.

  15. Mass balance to assess the efficiency of a mechanical-biological treatment

    International Nuclear Information System (INIS)

    Using mechanical-biological treatment of residual municipal solid waste, it is possible to significantly lower landfill volume and gas and leachate emissions. Moreover, the landfill characteristics are improved. The performance of the Mende (France) mechanical-biological treatment plant is assessed via mass balances coupled with manual sorting according to the MODECOMTM methodology and biochemical methane potential after 90 days of incubation. The site includes mechanical sorting operations, a rotary sequential bioreactor, controlled aerobic stabilisation corridors, maturation platforms, and a sanitary landfill site for waste disposal in separated cells. Results showed that several steps could be improved: after a first sieving step, about 12% of the potentially biodegradable matter is landfilled directly without any treatment; mechanical disintegration of papers and cardboards in the rotary sequential bioreactor is insufficient and leads to a high proportion of papers and cardboards being landfilled without further treatment. Two fine fractions go through stabilisation and maturation steps. At the end of the maturation step, about 54% of the potentially biodegradable matter is degraded. The biochemical methane potential after 90 days of incubation is reduced by 81% for one of the two fine fractions and reduced by 88% for the other one. Considering the whole plant, there is a reduction of nearly 20% DM of the entering residual municipal solid waste

  16. Emissions of the city of Augsburg determined using the mass balance method

    Energy Technology Data Exchange (ETDEWEB)

    Kalthoff, N.; Corsmeier, U.; Schmidt, K.; Kottmeier, C.; Fiedler, F. [Universitaet Karlsruhe (Germany). Institut fuer Meteorologie und Klimaforschung; Habram, M.; Slemr, F. [Fraunhofer Institut fuer Atmospharische Umweltforschung, Garmisch (Germany)

    2002-07-01

    Air quality models require emission data of air pollutants with high temporal and spatial resolution. The highly resolved emissions are calculated by complex emission models and may thus be subject to considerable uncertainties. To assess the uncertainty of the emission model calculations, emissions of the city of Augsburg in southern Germany were determined experimentally on several days in October 1998 using the technique of mass balance. Two algorithms were used to estimate the CO and NO{sub x} emissions from the data measured by two research aircraft, two tethered balloons, and an airship on the lateral surface enclosing the area of investigation. The two algorithms provided results which agree within the calculated uncertainties. The differences can be attributed mainly to the different interpolation methods applied to the layer between the lowest flight level and the ground. The measurements show that on the different weekdays both CO and NO{sub x} emissions varied by about a factor of two which is much larger than the variability predicted by the emission model. Higher than predicted CO emissions were observed on Saturday, 10 October 1998, whereas NO{sub x} emissions on 10 October were substantially smaller than predicted by the emission model. (author)

  17. Isotopic mass balance of Manzala Lake as indicators of present and past hydrogeological processes in Egypt

    International Nuclear Information System (INIS)

    Lakes are very important part of the aquatic ecosystem, which represent about 15% of the total commercial fishing areas in Egypt. Manzala lake is considered one of the largest lakes in Egypt. It is located in the north-eastern edge of the Nile delta and suffering from industrial and agricultural pollutions. The most serious source of pollution may be from Port Said and Damietta wastes, which dumped regularly into the lake. The main object of the present study is to investigate the hydrochemical and isotopic features of the lake waters and to compare the parameters deduced in the present and previous investigations in order to improve the current knowledge of the dynamic change during this time. The stable isotope (oxygen-18) component mass balance approach was used to find out the evaporation rate and the seepage from the groundwater to the lake. The data showed that the seepage rate from the groundwater to the lake was 305.54 x 106 m3/y (about 2% higher than previous study) since the amounts of drainage water became higher. The evaporation rate was 2185.844 x 106 m3/y (about 5% less than previous study). This is due to the reduction in the lake size. Although these rates are relatively small, yet they indicate an alarm for pollution propagation around the lake, which would increase with time

  18. Mass balance evolution of Martial Este Glacier, Tierra del Fuego (Argentina for the period 1960–2099

    Directory of Open Access Journals (Sweden)

    M. Buttstädt

    2009-12-01

    Full Text Available The Martial Este Glacier in southern Tierra del Fuego was studied in order to estimate the surface mass balance from 1960 until 2099. For this reason a degree-day model was calibrated. Air temperature and precipitation data obtained from 3 weather stations as well as glaciological measurements were applied. The model was driven using a vertical air temperature gradient of 0.69 K/100 m, a degree-day factor for snow of 4.7 mm w.e. K−1 day−1, a degree-day factor for ice of 9.4 mm w.e. K−1 day−1 and a precipitation gradient of 22%/100 m. For the purpose of surface mass balance reconstruction for the time period 1960 until 2006 a winter vertical air temperature gradient of 0.57 K/100 m and a summer vertical air temperature gradient of 0.71 K/100 m were added as well as a digital terrain model. The key finding is an almost continuous negative mass balance of −772 mm w.e. a−1 throughout this period. While the calculation of the mass balance for the period 1960–2006 is based on instrumental records, the mass balance for the years 2007 until 2099 was estimated based on the IPCC SRES A2-scenario. To accomplish this estimation, the dataset of the global climate model HadCM3 was statistically downscaled to fit local conditions at Martial Este Glacier. Subsequently, the downscaled air temperature and precipitation were applied to a volume-area scaling glacier change model. Findings reveal an enduring deglaciation resulting in a surface area reduction of nearly 93% until 2099. This implicates that the Martial Este Glacier might be melted off at the beginning of the 22nd century.

  19. Mass balance and surface velocity reconstructions of two reference Caucasus glaciers

    Science.gov (United States)

    Rybak, Oleg; Kaminskaia, Mariia; Kutuzov, Stanislav; Lavrentiev, Ivan; Morozova, Polina; Popovnin, Victor; Rybak, Elena

    2016-04-01

    Total glacial volume of the Greater Caucasus exceeds 40 cubic km and its area exceeds 1 thousand square km. During the 20th century, mountain glaciers at the Greater Caucasus were continuously degrading. According to various estimates, their area reduced more than one-third and their volume almost by half. The process of degradation was accompanied by growing population and economical development on surrounding territories. In the 21st century under proceeding global warming, a tendency of shrinking of area and volume of glaciation is obviously expected to continue. Working out of strategy of sustainable economic development of the region is the main motivation for elaboration of predictions of glaciers' evolution in the changing environment. Growing demand of fresh water is the basic challenge for the local economy, and efficient planning of water resources is impossible without knowing future state of glaciation. Therefore our research aims at obtaining accurate evaluation of probable future change of the most prominent mountain glaciers of the Greater Caucasus in forthcoming decades and at studying impacts of changing characteristics of glaciation on the run-off in the area. Initially, we focus on two so-called reference glaciers - Marukh (Western Caucasus) and Djankuat (Central Caucasus). Intensive field observations on both of them have been conducted during the last half of the century and essential amount of detailed relevant information has been collected on their geometry change and on mass balance. Besides, meteorological measurements were episodically carried out directly on the glaciers providing enough data for correlation of the local weather conditions with the data from the closest meteorological stations. That is why studying of response of Marukh and Djankuat on the environmental change can be accurately verified, which is crucial for understanding mechanisms driving evolution of large glaciated area in the Caucasus. As the instrument of research

  20. Greenland ice sheet surface mass-balance modeling in a 131-year perspective, 1950-2080

    Energy Technology Data Exchange (ETDEWEB)

    Mernild, Sebastian Haugard [Los Alamos National Laboratory; Liston, Glen [COLORADO STATE UNIV.; Hiemstra, Christopher [COLORADO STATE UNIV.; Christensen, Jens [DANISH METEOROLOGICAL INS.

    2009-01-01

    Fluctuations in the Greenland Ice Sheet (GrIS) surface mass-balance (SMB) and freshwater influx to the surrounding oceans closely follow climate fluctuations and are of considerable importance to the global eustatic sea level rise. SnowModel, a state-of-the-art snow-evolution modeling system, was used to simulate variations in the GrIS melt extent, surface water balance components, changes in SMB, and freshwater influx to the ocean. The simulations are based on the IPCC scenario AlB modeled by the HIRHAM4 RCM (using boundary conditions from ECHAM5 AOGCM) from 1950 through 2080. In-situ meteorological station (GC-Net and WMO DMI) observations from inside and outside the GrIS were used to validate and correct RCM output data before it was used as input for SnowModel. Satellite observations and independent SMB studies were used to validate the SnowModel output and confirm the model's robustness. We simulated a {approx}90% increase in end-of-summer surface melt extent (0.483 x 10{sup 6} km{sup 2}) from 1950 to 2080, and a melt index (above 2,000-m elevation) increase of 138% (1.96 x 10{sup 6} km{sup 2} x days). The greatest difference in melt extent occured in the southern part of the GrIS, and the greatest changes in the number of melt days was seen in the eastern part of the GrIS ({approx}50-70%) and was lowest in the west ({approx}20-30%). The rate of SMB loss, largely tied to changes in ablation processes, lead to an enhanced average loss of 331 km{sup 3} from 1950 to 2080, an average 5MB level of -99 km{sup 3} for the period 2070-2080. GrIS surface freshwater runoff yielded an eustatic rise in sea level from 0.8 {+-} 0.1 (1950-1959) to 1.9 {+-} 0.1 mm (2070-2080) sea level equivalent (SLE) y{sup -1}. The accumulated GrIS freshwater runoff contribution from surface melting equaled 160 mm SLE from 1950 through 2080.

  1. Quantifying groundwater dependence of a sub-polar lake cluster in Finland using an isotope mass balance approach

    Science.gov (United States)

    Isokangas, E.; Rozanski, K.; Rossi, P. M.; Ronkanen, A.-K.; Kløve, B.

    2015-03-01

    A stable isotope study of 67 kettle lakes and ponds situated on an esker aquifer (90 km2) in northern Finland was carried out to determine the role and extent of groundwater inflow in groundwater-dependent lakes. Distinct seasonal fluctuations in the δ18O and δ2H values of lakes are the result of seasonal ice cover prohibiting evaporation during the winter. An iterative isotope mass balance approach was used to calculate the inflow-to-evaporation ratios (ITOT/E) of all 67 lakes during the summer of 2013 when the isotopic compositions of the lakes were approaching a steady-state. The balance calculations were carried out independently for 2H and 18O data. Since evaporation rates were derived independently of any mass balance considerations, it was possible to determine the total inflow (ITOT) and mean turnover time (MTT) of the lakes. Furthermore, the groundwater seepage rates to all studied lakes were calculated. A quantitative measure was introduced for the dependence of a lake on groundwater (G index) that is defined as the percentage contribution of groundwater inflow to the total inflow of water to the given lake. The G index values of the lakes studied ranged from ca. 39 to 98%, revealing generally large groundwater dependency among the studied lakes. This study shows the effectiveness of applying an isotope mass balance approach to quantify the groundwater reliance of lakes situated in a relatively small area with similar climatic conditions.

  2. A model study of the energy and mass balance of Chhota Shigri glacier in the Western Himalaya, India

    Directory of Open Access Journals (Sweden)

    F. Pithan

    2011-01-01

    Full Text Available The impact of climate change on Himalaya mountain glaciers is increasingly subject of public and scientific debate. However, observational data are sparse and important knowledge gaps remain in the understanding of what drives changes in these glaciers' mass balances. The present study investigates the glacier regime on Chhota Shigri, a benchmark glacier for the observation of climate change in the monsoon-arid transition zone of Western Himalaya. Results of an energy-balance model driven by reanalysis data and the observed mass balances from three years on 50 m altitude intervals across the glacier display a correlation coefficient of 0.974. Contrary to prior assumptions, monsoon precipitation accounts for a quarter to a third of total accumulation. It has an additional importance because it lowers the surface albedo during the ablation season. Results confirm radiation as the main energy source for melt on Himalaya glaciers. Latent heat flux acts as an important energy sink in the pre-monsoon season. Mass balance is most sensitive to changes in atmospheric humidity, changing by 900 mm w.e. per 10% change in humidity. Temperature sensitivity is 220 mm w.e.K−1. Model results using 21st century anomalies from a regional climate model based on the SRES A2 scenario suggest that a monsoon increase might offset the effect of warming.

  3. Estimation of Groundwater Recharge at Pahute Mesa using the Chloride Mass-Balance Method

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Clay A [DRI; Hershey, Ronald L [DRI; Healey, John M [DRI; Lyles, Brad F [DRI

    2013-07-01

    Groundwater recharge on Pahute Mesa was estimated using the chloride mass-balance (CMB) method. This method relies on the conservative properties of chloride to trace its movement from the atmosphere as dry- and wet-deposition through the soil zone and ultimately to the saturated zone. Typically, the CMB method assumes no mixing of groundwater with different chloride concentrations; however, because groundwater is thought to flow into Pahute Mesa from valleys north of Pahute Mesa, groundwater flow rates (i.e., underflow) and chloride concentrations from Kawich Valley and Gold Flat were carefully considered. Precipitation was measured with bulk and tipping-bucket precipitation gauges installed for this study at six sites on Pahute Mesa. These data, along with historical precipitation amounts from gauges on Pahute Mesa and estimates from the PRISM model, were evaluated to estimate mean annual precipitation. Chloride deposition from the atmosphere was estimated by analyzing quarterly samples of wet- and dry-deposition for chloride in the bulk gauges and evaluating chloride wet-deposition amounts measured at other locations by the National Atmospheric Deposition Program. Mean chloride concentrations in groundwater were estimated using data from the UGTA Geochemistry Database, data from other reports, and data from samples collected from emplacement boreholes for this study. Calculations were conducted assuming both no underflow and underflow from Kawich Valley and Gold Flat. Model results estimate recharge to be 30 mm/yr with a standard deviation of 18 mm/yr on Pahute Mesa, for elevations >1800 m amsl. These estimates assume Pahute Mesa recharge mixes completely with underflow from Kawich Valley and Gold Flat. The model assumes that precipitation, chloride concentration in bulk deposition, underflow and its chloride concentration, have been constant over the length of time of recharge.

  4. Precursors predicted by artificial neural networks for mass balance calculations: Quantifying hydrothermal alteration in volcanic rocks

    Science.gov (United States)

    Trépanier, Sylvain; Mathieu, Lucie; Daigneault, Réal; Faure, Stéphane

    2016-04-01

    This study proposes an artificial neural networks-based method for predicting the unaltered (precursor) chemical compositions of hydrothermally altered volcanic rock. The method aims at predicting precursor's major components contents (SiO2, FeOT, MgO, CaO, Na2O, and K2O). The prediction is based on ratios of elements generally immobile during alteration processes; i.e. Zr, TiO2, Al2O3, Y, Nb, Th, and Cr, which are provided as inputs to the neural networks. Multi-layer perceptron neural networks were trained on a large dataset of least-altered volcanic rock samples that document a wide range of volcanic rock types, tectonic settings and ages. The precursors thus predicted are then used to perform mass balance calculations. Various statistics were calculated to validate the predictions of precursors' major components, which indicate that, overall, the predictions are precise and accurate. For example, rank-based correlation coefficients were calculated to compare predicted and analysed values from a least-altered test dataset that had not been used to train the networks. Coefficients over 0.87 were obtained for all components, except for Na2O (0.77), indicating that predictions for alkali might be less performant. Also, predictions are performant for most volcanic rock compositions, except for ultra-K rocks. The proposed method provides an easy and rapid solution to the often difficult task of determining appropriate volcanic precursor compositions to rocks modified by hydrothermal alteration. It is intended for large volcanic rock databases and is most useful, for example, to mineral exploration performed in complex or poorly known volcanic settings. The method is implemented as a simple C++ console program.

  5. A Mass balance mercury budget for a mine-dominated lake: Clear Lake, California

    Science.gov (United States)

    Suchanek, T.H.; Cooke, J.; Keller, K.; Jorgensen, S.; Richerson, P.J.; Eagles-Smith, C. A.; Harner, E.J.; Adam, D.P.

    2009-01-01

    The Sulphur Bank Mercury Mine (SBMM), active intermittently from 1873-1957 and now a USEPA Superfund site, was previously estimated to have contributed at least 100 metric tons (105 kg) of mercury (Hg) into the Clear Lake aquatic ecosystem. We have confirmed this minimum estimate. To better quantify the contribution of the mine in relation to other sources of Hg loading into Clear Lake and provide data that might help reduce that loading, we analyzed Inputs and Outputs of Hg to Clear Lake and Storage of Hg in lakebed sediments using a mass balance approach. We evaluated Inputs from (1) wet and dry atmospheric deposition from both global/regional and local sources, (2) watershed tributaries, (3) groundwater inflows, (4) lakebed springs and (5) the mine. Outputs were quantified from (1) efflux (volatilization) of Hg from the lake surface to the atmosphere, (2) municipal and agricultural water diversions, (3) losses from out-flowing drainage of Cache Creek that feeds into the California Central Valley and (4) biotic Hg removal by humans and wildlife. Storage estimates include (1) sediment burial from historic and prehistoric periods (over the past 150-3,000 years) from sediment cores to ca. 2.5m depth dated using dichloro diphenyl dichloroethane (DDD), 210Pb and 14C and (2) recent Hg deposition in surficial sediments. Surficial sediments collected in October 2003 (11 years after mine site remediation) indicate no reduction (but a possible increase) in sediment Hg concentrations over that time and suggest that remediation has not significantly reduced overall Hg loading to the lake. Currently, the mine is believed to contribute ca. 322-331 kg of Hg annually to Clear Lake, which represents ca. 86-99% of the total Hg loading to the lake. We estimate that natural sedimentation would cover the existing contaminated sediments within ca. 150-300 years. ?? 2008 Springer Science+Business Media B.V.

  6. Waste assay and mass balance for the decontamination and volume reduction system at LANL

    Energy Technology Data Exchange (ETDEWEB)

    Gruetzmacher, Kathleen M.; Ferran, Scott G.; Garner, Scott E.; Romero, Mike J.; Christensen, Davis V.; Bustos, Roland M.

    2003-07-01

    The Decontamination and Volume Reduction System (DVRS) operated by the Solid Waste Operations (SWO) Group at Los Alamos National Laboratory (LANL) processes large volume, legacy radioactive waste items. Waste boxes, in sizes varying from 4 ft x 4 ft x 8 ft to 10 ft x 12 ft x 40 ft, are assayed prior to entry into the processing building. Inside the building, the waste items are removed from their container, decontaminated and/or size reduced if necessary, and repackaged for shipment to the Waste Isolation Pilot Plant (WIPP) or on-site low-level waste disposal. The repackaged items and any secondary waste produced (e.g., personal protective equipment) are assayed again at the end of the process and a mass balance is done to determine whether there is any significant hold-up material left in the DVRS building. The DVRS building is currently classed as a radiological facility, with a building limit of 0.52 Ci of Pu239 and Am241, and 0.62 Ci of Pu238, the most common radionuclides processed. This requires tight controls on the flow of nuclear material. The large volume of the initial waste packages, the (relatively) small amounts of radioactive material in them, and the tight ceiling on the building inventory require accurate field measurements of the nuclear material. This paper describes the radioactive waste measurement techniques, the computer modeling used to determine the amount of nuclear material present in a waste package, the building inventory database, and the DVRS process itself. Future plans include raising the limit on the nuclear material inventory allowed in the building to accommodate higher activity waste packages. All DOE sites performing decontamination and decommissioning of radioactive process equipment face challenges related to waste assay and inventory issues. This paper describes an ongoing operation, incorporating lessons learned over the life of the project to date.

  7. Fate, mass balance, and transport of phosphorus in the septic system drainfields.

    Science.gov (United States)

    Mechtensimer, Sara; Toor, Gurpal S

    2016-09-01

    Septic systems can be a potential source of phosphorus (P) in shallow groundwater. Our objective was to investigate the fate, mass balance, and transport of P in the drainfield of a drip-dispersal septic system. Drainfields were replicated in lysimeters (152.4 cm long, 91.4 cm wide, and 91.4 cm high). Leachate and effluent samples were collected over 67 events (n = 15 daily; n = 52 weekly flow-weighted) and analyzed for total P (TP), orthophosphate (PO4P), and other P (TP - PO4P). Mean TP was 15 mg L(-1) (84% PO4P; 16% other P) in the effluent and 0.16 mg L(-1) (47% PO4P, 53% other P) in the leachate. After one year, 46.8 g of TP was added with effluent and rainfall to each drainfield, of which, 95% in the drainfield. Effluent dispersal increased water extractable P (WEP) in the drainfield from 10 mg kg(-1). Using the P sorption maxima of sand (118 mg kg(-1)) and soil (260 mg kg(-1)), we estimated that ∼18% of the drainfield P sorption capacity was saturated after one year of effluent dispersal. We conclude that despite the low leaching potential of P dispersed with effluent in the first year of drainfield operation, a growing WEP pool in the drainfield and low P sorption capacity of Florida's sandy soils may have the potential to transport P to shallow groundwater in long-running septic systems. PMID:27288645

  8. Mass Balance Model for Sustainable Phosphorus Recovery in a US Wastewater Treatment Plant.

    Science.gov (United States)

    Venkatesan, Arjun K; Hamdan, Abdul-Hakeem M; Chavez, Vanessa M; Brown, Jasmine D; Halden, Rolf U

    2016-01-01

    In response to limited phosphorus (P) reserves worldwide, several countries have demonstrated the prospect of recovering significant amounts of P from wastewater treatment plants (WWTPs). This technique uses enhanced biological P removal (EBPR) to concentrate P in sludge followed by chemical precipitation of P as struvite, a usable phosphate mineral. The present study models the feasibility of this enhanced removal and recovery technique in a WWTP in Arizona with design parameters typical of infrastructure in the United States. A mass balance was performed for existing treatment processes and modifications proposed to estimate the quantity of P that could be recovered under current and future flow conditions. Modeling results show that about 71 to 96% of the P being lost potentially could be recovered as struvite. About 491 ± 64 t yr of struvite may be recovered after process modification, which corresponds to $150,000 ± $20,000 yr in P sales to fertilizer industries. The process was projected to be economically feasible, with a payback period of 45 ± 30 yr in the studied WWTP and a much shorter duration of 3 ± 1 yr for WWTPs already using an EBPR process. Furthermore, modeling results suggest that P recovery can improve the quality of biosolids by favorably reducing the P:N ratio. Implementation of this strategy at US WWTPs may increase national security by reducing dependence of limited P resources. Considering all aspects of the recovery process with respect to environmental, economic, and social implications, the examined technique is concluded to represent a cost-attractive and sustainable method for P management in US WWTPs.

  9. Bulk arc strain, crustal thickening, magma emplacement, and mass balances in the Mesozoic Sierra Nevada arc

    Science.gov (United States)

    Cao, Wenrong; Paterson, Scott; Saleeby, Jason; Zalunardo, Sean

    2016-03-01

    Quantifying crustal deformation is important for evaluating mass balance, material transfer, and the interplay between tectonism and magmatism in continental arcs. We present a dataset of >650 finite strain analyses compiled from published works and our own studies with associated structural, geochronologic, and geobarometric information in central and southern Sierra Nevada, California, to quantify the arc crust deformation. Our results show that Mesozoic tectonism results in 65% arc-perpendicular bulk crust shortening under a more or less plane strain condition. Mesozoic arc magmatism replaced ∼80% of this actively deforming arc crust with plutons requiring significantly greater crustal thickening. We suggest that by ∼85 Ma, the arc crust thickness was ∼80 km with a 30-km-thick arc root, resulting in a ∼5 km elevation. Most tectonic shortening and magma emplacement must be accommodated by downward displacements of crustal materials into growing crustal roots at the estimated downward transfer rate of 2-13 km/Myr. The downward transfer of crustal materials must occur in active magma channels, or in "escape channels" in between solidified plutons that decrease in size with time and depth resulting in an increase in the intensity of constrictional strain with depth. We argue that both tectonism and magmatism control the thickness of the crust and surface elevation with slight modification by surface erosion. The downward transported crustal materials initially fertilize the MASH zone thus enhancing to the generation of additional magmas. As the crustal root grows it may potentially pinch out and cool the mantle wedge and thus cause reduction of arc magmatism.

  10. Dynamics and Mass Balance of Riiser-Larsen Ice Shelf, Antarctica, and its Drainage Area

    Science.gov (United States)

    Klauke, S.; Oelke, C.; Kleiner, T.; Lange, M. A.; Baessler, M.; Dietrich, R.

    2006-12-01

    A coupled finite difference ice sheet/ice shelf model is used to investigate the flow regime of Riiser-Larsen ice shelf, Eastern Weddell Sea, Antarctica, and its drainage area. The model takes into account higher order terms that are neglected in the popular shallow ice approximation. The modeled region has a total area of roughly 130 · 103 km2. The model grid consists of 2.5 km × 2.5 km cells horizontally, and of 10 sigma layers vertically. As input data for the simulation, a new DEM is derived mainly from recent ICESat/GLAS laser-altimetry data. In the ice sheet part of the modeled area, ice thickness data are taken from the BEDMAP data set. For the ice shelf, the thickness distribution is computed from the DEM by assuming isostatic equilibrium. For this purpose, vertical density variations inside the ice shelf are derived by comparison of GLAS altimetry data with airborne RES ice thickness measurements from the EPICA mission. The modeled ice flow velocity is compared with interferometrically derived surface flow velocities from ERS-SAR scenes of the ice sheet and with published in-situ measurements of the ice shelf. In order to minimize the difference between modeled and measured velocities, the boundary conditions and free parameters of the flow model are adjusted. The boundary condition at the ice-rock interface turns out to play a crucial role in optimizing the agreement. Thus, the basal sliding velocity of the ice body is calculated from the basal temperature and the basal shear stress following a widely used relation originally proposed by Weertman, and by adjusting its parameters. In the ice shelf, the viscosity of the ice is used as a tuning parameter and is adjusted to maximize the agreement with in-situ measurements. From the result of the simulation with an optimal set of parameters a mass flow over the grounding line of roughly 2 · 1013 kg yr-1 is derived. The comparison with published surface accumulation data suggests a stable mass balance for

  11. Coupled heat/mass-balance model for analyzing correlation between excess AlF3 concentration and aluminum electrolyte temperature

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-bo; QU Xiang-dong; ZHOU Jie-min

    2009-01-01

    The influence of aluminum electrolyte component on its temperature is an important issue within the field of aluminum reduction with pre-baked cells. The characteristic correlation between excess AlF3 concentration and aluminum electrolyte temperature was explored through the modeling of heat and mass transfer processes in industrial pre-baked aluminum reduction cells. A coupled heat/mass-balance model was derived theoretically from the mass and energy balance of an electrolysis cell, and then was simplified properly into a practical expression. The model demonstrates that if environmental temperature and Al2O3 concentration keep constant, the excess AlF3 concentration decreases with the aluminum electrolyte temperature linearly and its decrease rate is dependent on the heat transfer property of aluminum electrolyte, side wall and cell shell. Secondly, experiments were conducted on site with two industrial cells in an aluminum electrolysis plant. Excess AlF3 concentration and aluminum electrolyte temperature were obtained simultaneously together with other parameters such as Al2O3, CaF2, MgF2 and LiF concentrations. Results show that the maximum absolute error between the tested value and the calculated value of excess AlF3 concentration using the proposed model is less than 2%. This reveals that the coupled heat/mass-balance model can appropriately characterize the correlation between excess AlF3 concentration and aluminum electrolyte temperature with good accuracy and practicability.

  12. Mass balance evolution on two glaciers in the ecuadorian Andes (0°28'S) since the mid-20th century

    Science.gov (United States)

    Basantes, Ruben; Rabatel, Antoine; Alvarez, Danilo; Francou, Bernard; Galarraga, Remigio; Maisincho, Luis; Caceres, Bolivar

    2014-05-01

    The glacier mass balance evolution on two glaciers (Antisana Glacier 12 and Antisana Glacier 15α) in the tropical Andes is presented. To this end, photogrammetry technique was applied on aerial images taken at five dates: 1956, 1965, 1979, 1997 and 2009. For each date, digital elevation models (DEMs) were generated with an average vertical accuracy of ±2.2 m. The spatiotemporal volume variation of the glaciers is calculated through the elevations differences between DEMs and a density factor. The outcomes show that after 1970s the glaciers have experimented a strong recession even if a noticeable increase in mass was detected between 1965 and 1979. From 1979 to 1997, the ablation rates have dramatically increased and the average annual mass balance reached very negative values (-1.1 m w.e. yr-1 for Antisana Glacier 15α and -0.8 m w.e. yr-1 for Antisana Glacier 12). In the last study period, from 1997 to 2009, the glaciers average annual mass balances were less negative (-0.6 m w.e. yr-1 for Antisana Glacier 12 and -0.2 m w.e. yr-1 for Antisana Glacier 15α). The later matched with the period of conventional observations allowing compare the results given by both methodologies, i.e. geodetic and glaciological methods. However, some morphological constraints affecting the figures observed in the glaciological mass balance must be considered. Finally, we performed an analysis of the relationship between the glacier changes and the climate conditions over the study periods in order to understand how climate has impacted the glacier retreat in this region. For such an aim, local climate variables, i.e. temperature and precipitation, as well as regional indices, i.e. Pacific Decadal Oscillation (PDO) and Multivariate ENSO Index (MEI) have been used. The outcomes show a high correlation between the climate signals and the glacier behavior at both annual and decadal time scales.

  13. A Mass Balance Model for Designing Green Roof Systems that Incorporate a Cistern for Re-Use

    OpenAIRE

    Manoj Chopra; Martin Wanielista; Mike Hardin

    2012-01-01

    Green roofs, which have been used for several decades in many parts of the world, offer a unique and sustainable approach to stormwater management. Within this paper, evidence is presented on water retention for an irrigated green roof system. The presented green roof design results in a water retention volume on site. A first principle mass balance computer model is introduced to assist with the design of these green roof systems which incorporate a cistern to capture and reuse runoff waters...

  14. A case-study on the accuracy of mass balances for xenobiotics in full-scale wastewater treatment plants.

    Science.gov (United States)

    Majewsky, Marius; Farlin, Julien; Bayerle, Michael; Gallé, Tom

    2013-04-01

    Removal efficiencies of micropollutants in wastewater treatment plants (WWTPs) are usually evaluated from mass balance calculations using a small number of observations drawn from short sampling campaigns. Since micropollutant loads can vary greatly in both influent and effluent and reactor tanks exhibit specific hydraulic residence times, these short-term approaches are particularly prone to yield erroneous removal values. A detailed investigation of micropollutant transit times at full-scale and on how this affects mass balancing results was still lacking. The present study used hydraulic residence time distributions to scrutinize the match of influent loads to effluent loads of 10 polar micropollutants with different influent dynamics in a full-scale WWTP. Prior hydraulic modeling indicated that a load sampled over one day in the effluent is composed of influent load fractions of five preceding days. Results showed that the error of the mass balance can be reduced with increasing influent sampling duration. The approach presented leads to a more reliable estimation of the removal efficiencies of those micropollutants which can be constantly detected in influents, such as pharmaceuticals, but provides no advantage for pesticides due to their sporadic occurrence. The mismatch between sampled influent and effluent loads was identified as a major error source and an explanation was provided for the occurrence of negative mass balances regularly reported. This study indicates that the accurate determination of global removal values is only feasible in full-scale investigations with sampling durations much longer than 1 day. In any case, the uncertainty of these values needs to be reported when used in removal assessment, model selection or validation. PMID:23474799

  15. Mass-energy balance analysis for estimation of light energy conversion in an integrated system of biological H2 production

    OpenAIRE

    A.I. Gavrisheva; B.F. Belokopytov; V.I. Semina; E.S. Shastik; T.V. Laurinavichene; A.A. Tsygankov

    2015-01-01

    The present study investigated an integrated system of biological H2 production, which includes the accumulation of biomass of autotrophic microalgae, dark fermentation of biomass, and photofermentation of the dark fermentation effluent. Particular emphasis was placed on the estimation of the conversion efficiency of light into hydrogen energy at each stage of this system. For this purpose, the mass and energy balance regularities were applied. The efficiency of the energy transformation from...

  16. Estimation of air–water gas exchange coefficient in a shallow lagoon based on 222Rn mass balance

    International Nuclear Information System (INIS)

    The radon-222 mass balance is now commonly used to quantify water fluxes due to Submarine Groundwater Discharge (SGD) in coastal areas. One of the main loss terms of this mass balance, the radon evasion to the atmosphere, is based on empirical equations. This term is generally estimated using one among the many empirical equations describing the gas transfer velocity as a function of wind speed that have been proposed in the literature. These equations were, however, mainly obtained from areas of deep water and may be less appropriate for shallow areas. Here, we calculate the radon mass balance for a windy shallow coastal lagoon (mean depth of 6 m and surface area of 1.55*108 m2) and use these data to estimate the radon loss to the atmosphere and the corresponding gas transfer velocity. We present new equations, adapted to our shallow water body, to express the gas transfer velocity as a function of wind speed at 10 m height (wind range from 2 to 12.5 m/s). When compared with those from the literature, these equations fit particularly well with the one of Kremer et al. (2003). Finally, we emphasize that some gas transfer exchange may always occur, even for conditions without wind. - Highlights: • We used, for the first time, a radon mass balance approach to determine gas transfer exchange in a shallow area. • We were more particularly able to highlight that gas transfer occurred for low wind or for conditions without winds. • We also expressed new expressions for the gas transfer coefficient as a function of wind speed in shallow areas

  17. Theory of the generalized chloride mass balance method for recharge estimation in groundwater basins characterised by point and diffuse recharge

    OpenAIRE

    N. Somaratne; Smettem, K. R. J.

    2014-01-01

    Application of the conventional chloride mass balance (CMB) method to point recharge dominant groundwater basins can substantially under-estimate long-term average annual recharge by not accounting for the effects of localized surface water inputs. This is because the conventional CMB method ignores the duality of infiltration and recharge found in karstic systems, where point recharge can be a contributing factor. When point recharge is present in groundwater basins,...

  18. Estimating Natural Recharge by Means of Chloride Mass Balance in a Volcanic Aquifer: Northeastern Gran Canaria (Canary Islands, Spain)

    OpenAIRE

    Gema Naranjo; Tatiana Cruz-Fuentes; María del Carmen Cabrera; Emilio Custodio

    2015-01-01

    The chloride mass balance method was used to estimate the average diffuse groundwater recharge on northeastern Gran Canaria (Canary Islands), where the largest recharge to the volcanic island aquifer occurs. Rainwater was sampled monthly in ten rainwater collectors to determine the bulk deposition rate of chloride for the 2008-2014 period. Average chloride deposition decreases inwardly from more than 10 g center dot m(-2)center dot year(-1) to about 4 g center dot m(-2)center dot year(-1). Th...

  19. Catchment conceptualisation for examining applicability of chloride mass balance method in an area of historical forest clearance

    OpenAIRE

    H. Guan; Love, A.; C. T. Simmons; Ding, Z; Hutson, J

    2009-01-01

    Among various approaches for estimating groundwater recharge, chloride mass balance (CMB) method is one of the most frequently used, in particular, for arid and semiarid regions. Widespread native vegetation clearance, common history in many areas globally, has changed land surface boundary condition, posing a question whether the current system has reached new chloride equilibrium for CMB application. To examine CMB applicability for catchments, conceptual catchment types of various chloride...

  20. Catchment conceptualisation for examining applicability of chloride mass balance method in an area with historical forest clearance

    OpenAIRE

    H. Guan; Love, A. J.; C. T. Simmons; Hutson, J; Ding, Z

    2010-01-01

    Of the various approaches for estimating groundwater recharge, the chloride mass balance (CMB) method is one of the most frequently used, especially for arid and semiarid regions. Widespread native vegetation clearance, common in many areas globally, has changed the land surface boundary condition, posing the question as to whether the current system has reached new chloride equilibrium, required for a CMB application. Although a one-dimensional CMB can be applied at a point where the water a...

  1. Aquifer Recharge Estimation through Atmospheric Chloride Mass Balance at Las Cañadas Caldera, Tenerife, Canary Islands, Spain

    OpenAIRE

    Rayco Marrero-Diaz; Alcalá, Francisco J.; Nemesio M. Pérez; Dina L. López; Gladys V. Melián; Eleazar Padrón; Germán D. Padilla

    2015-01-01

    The atmospheric chloride mass balance (CMB) method was used to estimate net aquifer recharge in Las Cañadas Caldera, an endorheic summit aquifer area about 2000 m a.s.l. with negligible surface runoff, which hosts the largest freshwater reserve in Tenerife Island, Canary Islands, Spain. The wet hydrological year 2005–2006 was selected to compare yearly atmospheric chloride bulk deposition and average chloride content in recharge water just above the water table, both deduced from periodical...

  2. Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model

    OpenAIRE

    Angelen, J. H.; Lenaerts, J. T. M.; S. Lhermitte; X. Fettweis; P. Kuipers Munneke; M. R. van den Broeke; van Meijgaard, E.

    2012-01-01

    We present a sensitivity study of the surface mass balance (SMB) of the Greenland Ice Sheet, as modeled using a regional atmospheric climate model, to various parameter settings in the albedo scheme. The snow albedo scheme uses grain size as a prognostic variable and further depends on cloud cover, solar zenith angle and black carbon concentration. For the control experiment the overestimation of absorbed shortwave radiation (+6%) at the K-transect (west Greenland) for the period 2004–2009 is...

  3. Application of a contaminant mass balance method at an old landfill to assess the impact on water resources

    DEFF Research Database (Denmark)

    Thomsen, Nanna Isbak; Milosevic, Nemanja; Bjerg, Poul Løgstrup

    2012-01-01

    Old and unlined landfill sites pose a risk to groundwater and surface water resources. While landfill leachate plumes in sandy aquifers have been studied, landfills in clay till settings and their impact on receiving water bodies are not well understood. In addition, methods for quantitatively...... linking soil and groundwater contamination to surface water pollution are required. This paper presents a method which provides an estimate of the contaminant mass discharge, using a combination of a historical investigation and contaminant mass balance approach. The method works at the screening level...

  4. Material-mass Balance of Smallholder Oil Palm Processing in the Niger Delta, Nigeria

    Directory of Open Access Journals (Sweden)

    Elijah I. Ohimain

    2013-03-01

    Full Text Available This study evaluates the material-mass balance of smallholder oil palm processing in Niger Delta Nigeria. Ten smallholder oil palm processing mills were randomly sampled. Measuring scale was used to measure the weight of the Fresh Fruit Bunch (FFB and all the processing intermediates/products including Threshed Fresh Fruit (TFF, Palm Pressed Fibre (PPF, Palm Kernel Shell (PKS, Empty Fruit Bunch (EFB, Crude Palm Oil (CPO, chaff and nut. During the study period (13-22 April 2012, 8 of the mills processed 90-400 bunches of Dura variety, while the remaining 2 mills processed 65-200 bunches of Tenera variety. During the batch processing of Dura variety, the proportion of the intermediate products computed in relation to the weight of the FFB (100% are as follows; TFF (66.0-75.0%, mesocarp (44.8-51.1%, nuts (19.0-27.5%, kernel (5.7-7.2%, water in mesocarp (9.0-12.1% and water in nut (2.4-3.4%, EFB (23.7-32.4%, chaff (0.8-2.4%, Palm Kernel Shell (PKS (10.0-18.8%, Palm Press Fibre (PPF (23.2-28.1% and Crude Palm Oil (CPO (9.4-12.8%. For the Tenera varieties, the compositions are as follows; TFF (70.9-72.9%, mesocarp (56.4-58.0%, nuts (14.5-14.9%, kernel (5.5-5.6%, water in mesocarp (10.1-10.4% and water in the nut (1.9-2.1%, EFB (25.7-28.2%, chaff (0.9-1.4%, PKS (6.8-7.5%, (19.1-20.3% and CPO (26.0-28.2%. This result shows that Tenera produces more oil and less wastes compared to the Dura variety. The solid wastes fractions are used as energy sources during the processing of oil palm and as filling materials for upgrading access roads to palm plantations. Except the huge volume of wastes (71.8-90.6% generated by smallholder oil palm processors is effectively utilized, the process will be unsustainable.

  5. Atmospheric Ammonia Emissions and a Nitrogen Mass Balance for a Dairy

    Science.gov (United States)

    Rumburg, B. P.; Mount, G. H.; Filipy, J. M.; Lamb, B.; Yonge, D.; Wetherelt, S.

    2003-12-01

    Atmospheric ammonia (NH3) emissions have many impacts on the environment and human health. Environmental NH3 impacts include terrestrial and aquatic eutrophication, soil acidification, and aerosol formation. Aerosols affect global radiative transfer and have been linked to human health effects. The global emissions of NH3 are estimated to be 45 Tg N yr-1 (Dentener and Crutzen, 1994) with most of the emissions coming from domestic animals. The largest per animal emission come from dairy cows at 33 kg N animal{-1} year{-1} versus 10 kg N animal{-1} {-1} for cattle. On a global scale the emissions uncertainty is about 25%, but local emissions are highly uncertain (Bouwman et al., 1997). Local emissions determination is required for proper treatment in air pollution models. The main sources of emission from dairies are the cow stalls where urea and manure react to form NH3, the storage lagoons where NH3 is the end product of microbial degradation and the disposal of the waste. There have been numerous studies of NH3 emissions in Europe but farming practices are quite different in Europe than in the U.S.. The impact of these differences on emissions is unknown. We have been studying the NH3 emissions from the Washington State University dairy for three years to develop a detailed emission model for use in a regional air pollution model. NH3 is measured using a short-path spectroscopic absorption near 200 nm with a sensitivity of a few ppbv and a time resolution of a few seconds. The open air short-path method is advantageous because it is self calibrating and avoids inlet wall adherence which is a major problem for most NH3 measurement techniques. A SF6 tracer technique has been used to measure fluxes from the three main emission sources: the cow stalls, anaerobic lagoon and the waste application to grass fields using a sprinkler system. Estimated yearly emissions from each source will be compared to a nitrogen mass balance model for the dairy.

  6. [Characteristic of Mercury Emissions and Mass Balance of the Typical Iron and Steel Industry].

    Science.gov (United States)

    Zhang, Ya-hui; Zhang, Cheng; Wang, Ding-yong; Luo, Cheng-zhong; Yang, Xi; Xu, Feng

    2015-12-01

    To preliminarily discuss the mercury emission characteristics and its mass balance in each process of the iron and steel production, a typical iron and steel enterprise was chosen to study the total mercury in all employed materials and estimate the input and output of mercury during the steel production process. The results showed that the mercury concentrations of input materials in each technology ranged 2.93-159.11 µg · kg⁻¹ with the highest level observed in ore used in blast furnace, followed by coal of sintering and blast furnace. The mercury concentrations of output materials ranged 3.09-18.13 µg · kg⁻¹ and the mercury concentration of dust was the highest, followed by converter slag. The mercury input and the output in the coking plant were 1346.74 g · d⁻¹ ± 36.95 g · d⁻¹ and 177.42 g · d⁻¹ ± 13.73 g · d⁻¹, respectively. In coking process, mercury mainly came from the burning of coking coal. The sintering process was the biggest contributor for mercury input during the iron and steel production with the mercury input of 1075. 27 g · d⁻¹ ± 60.89 g · d⁻¹ accounting for 68.06% of the total mercury input during this production process, and the ore powder was considered as the main mercury source. For the solid output material, the output in the sintering process was 14.15 g · d⁻¹ ± 0.38 g · d⁻¹, accounting for 22.61% of the total solid output. The mercury emission amount from this studied iron and steel enterprise was estimated to be 553.83 kg in 2013 with the emission factor of 0.092 g · t⁻¹ steel production. Thus, to control the mercury emissions, iron and steel enterprises should combine with production practice, further reduce energy consumption of coking and sintering, or improve the quality of raw materials and reduce the input of mercury.

  7. Steady-state mass balance model for mercury in the St. Lawrence River near Cornwall, Ontario, Canada

    International Nuclear Information System (INIS)

    We have developed a local mass balance model for the St. Lawrence River near Cornwall, Ontario that describes the fate and transport of mercury in three forms, elemental, divalent, and methylated, in a five compartment environment (air, water, sediments, periphyton, and benthos). Our objective was to construct a steady-state mass balance model to determine the dominant sources and sinks of mercury in this environment. We compiled mercury concentrations, fluxes, and transformation rates from previous studies completed in this section of the river to develop the model. The inflow of mercury was the major source to this system, accounting for 0.42 mol month−1, or 95.5% of all mercury inputs, whereas outflow was 0.28 mol month−1, or 63.6% of all losses, and sediment deposition was 0.12 mol month−1, or 27.3% of all losses. Uncertainty estimates were greatest for advective fluxes in surface water, porewater, periphyton, and benthic invertebrates. -- Highlights: ► Inflow accounted for 95.5% of all mercury inputs to the St. Lawrence River near Cornwall. ► Major losses of mercury were by outflow (63%) and sedimentation (27%). ► Sediments account for over 94% of all mercury in the system. -- A steady-state mass balance model is presented for mercury species in the St. Lawrence River near Cornwall, Ontario

  8. Modeling mass balance and volume of Xiao Dongkemadi glacier in the Central Tibetan Plateau from 1989 to 2050

    Science.gov (United States)

    Duan, K.

    2015-12-01

    The Tibetan Plateau (TP) holds ten thousands of alpine glaciers in mid-latitude, which have shrunk with an accelerating retreat rate recently. Here, we applied a temperature-index distributed mass-balance model coupled with a volume-area scaling method to Xiao Dongkemadi Glacier (XDG) in the central TP, to assess its response to climate change. The result shows the simulated mass balance is in a good agreement with observations (R2=0.75, p<0.001) during the period of 1989-2012. The simulated mean annual mass balance (-213 mm w.e.) is close to the observation (-233 mm w.e.), indicating the model can be used to estimate the glacier variation in the future. Then the model was forced by the output of RegCM4 under the climate scenarios RCP4.5 and RCP8.5 from 2013 to 2050. The simulated terminus elevation of the glacier will rise from 5454m a.s.l. in 2013 to 5533m a.s.l. (RCP4.5) and 5543m a.s.l (RCP8.5) in 2050. XDG will lose its volume with an increasing rate of 600-700m3 a-1 during the period of 1989-2050, indicating the melting water will enhance the river runoff. But for the long term, the contribution to the river runoff will decrease for shrinkage of glacier scale.

  9. The Mass Balance of Glacier No. 1 at the Headwaters of the Urumqi River in Relation to Northern Hemisphere Teleconnection Patterns

    Directory of Open Access Journals (Sweden)

    Feifei Yuan

    2016-03-01

    Full Text Available Most small glaciers in the world have significantly decreased their volume during the last century, which has caused water shortage problems. Glacier No. 1, at the headwaters of the Urumqi River, Tianshan, China, has been monitored since 1959 and similarly has experienced significant mass and volume losses over the last few decades. Thus, we examined the trend and potential abrupt changes of the mass balance of Glacier No. 1. Principal component analysis and singular value decomposition were used to find significant relations between the mass balance of Glacier No. 1 and Northern Hemisphere teleconnection patterns using climate indices. It was found that the mass balance of Glacier No. 1 had a significantly decreasing trend corresponding to −14.5 mm/year from 1959 to 2010. A change point was detected in 1997 with 99% confidence level. Two time periods with different mass balances were identified as 1959–1996 and 1997–2010. The mass balance for the first period was −136.4 mm/year and up to −663.9 mm/year for the second period. The mass balance of Glacier No. 1 is positively related to the Scandinavian Pattern (SCA, and negatively related to the East Atlantic Pattern (EA. These relationships are useful in better understanding the interaction between glacier mass balance and climate variability.

  10. Electrode Mass Balancing as an Inexpensive and Simple Method to Increase the Capacitance of Electric Double-Layer Capacitors

    Science.gov (United States)

    Andres, Britta; Engström, Ann-Christine; Blomquist, Nicklas; Forsberg, Sven; Dahlström, Christina; Olin, Håkan

    2016-01-01

    Symmetric electric double-layer capacitors (EDLCs) have equal masses of the same active material in both electrodes. However, having equal electrode masses may prevent the EDLC to have the largest possible specific capacitance if the sizes of the hydrated anions and cations in the electrolyte differ because the electrodes and the electrolyte may not be completely utilized. Here we demonstrate how this issue can be resolved by mass balancing. If the electrode masses are adjusted according to the size of the ions, one can easily increase an EDLC’s specific capacitance. To that end, we performed galvanostatic cycling to measure the capacitances of symmetric EDLCs with different electrode mass ratios using four aqueous electrolytes— Na2SO4, H2SO4, NaOH, and KOH (all with a concentration of 1 M)—and compared these to the theoretical optimal electrode mass ratio that we calculated using the sizes of the hydrated ions. Both the theoretical and experimental values revealed lower-than-1 optimal electrode ratios for all electrolytes except KOH. The largest increase in capacitance was obtained for EDLCs with NaOH as electrolyte. Specifically, we demonstrate an increase of the specific capacitance by 8.6% by adjusting the electrode mass ratio from 1 to 0.86. Our findings demonstrate that electrode mass balancing is a simple and inexpensive method to increase the capacitance of EDLCs. Furthermore, our results imply that one can reduce the amount of unused material in EDLCs and thus decrease their weight, volume and cost. PMID:27658253

  11. Glaciers in a changing global climate: first results of worldwide glacier mass balance measurements 2000/2001

    Science.gov (United States)

    Frauenfelder, R.; Hoelzle, M.; Haeberli, W.

    2003-04-01

    Glacier signals from mountain areas are key elements of early detection strategies for dealing with possible man-induced climate change. The IPCC Third Assessment Report indeed defines mountain glaciers as one of the best natural indicators of atmospheric warming with the highest reliability ranking. In the chain of processes linking climate and glacier fluctuations, glacier length variation is the indirect/delayed response, whereas glacier mass change is the direct/undelayed reaction. Internationally coordinated long-term monitoring of glaciers started in 1894. The responsibility to collect and publish standardized data has been assumed since 1986 by the World Glacier Monitoring Service (WGMS). This work is primarily being carried out under the auspices of the International Commission on Snow and Ice (ICSI/IAHS) and the Federation of Astronomical and Geophysical Services (FAGS/ICSU). The WGMS maintains data exchange with the ICSU World Data Center A (WDC-A) for Glaciology in Boulder, Colorado. Corresponding data bases and measurement networks form an essential part of the Global Terrestrial Network for Glaciers (GTN-G: operated by the WGMS) as a pilot project within the Global Terrestrial Observing System (GTOS/GCOS). A network of 60 glacier mass balance observations provides information on presently observed rates of change in glacier mass, corresponding acceleration trends and regional distribution patterns. A preliminary calculation of the mass balance observations in 2000/2001 relating to 23 selected data sets provide a mean specific (annual) net balance of -367 mm w.e., 26 % of the observed balances were positive. The corresponding mean in six mountain ranges was -571 mm w.e. Such values indicate that mass losses in 2000/2001 have been less extreme than in the extraordinary years before but are still strongly negative. Over the past two decades glacier melt appears to continue at a considerable and possibly even an accelerating rate. The observed average

  12. A Preliminary Model for Spacecraft Propulsion Performance Analysis Based on Nuclear Gain and Subsystem Mass-Power Balances

    Science.gov (United States)

    Chakrabarti, Suman; Schmidt, George R.; Thio, Y. C.; Hurst, Chantelle M.

    1999-01-01

    A preliminary model for spacecraft propulsion performance analysis based on nuclear gain and subsystem mass-power balances are presented in viewgraph form. For very fast missions with straight-line trajectories, it has been shown that mission trip time is proportional to the cube root of alpha. Analysis of spacecraft power systems via a power balance and examination of gain vs. mass-power ratio has shown: 1) A minimum gain is needed to have enough power for thruster and driver operation; and 2) Increases in gain result in decreases in overall mass-power ratio, which in turn leads to greater achievable accelerations. However, subsystem mass-power ratios and efficiencies are crucial: less efficient values for these can partially offset the effect of nuclear gain. Therefore, it is of interest to monitor the progress of gain-limited subsystem technologies and it is also possible that power-limited systems with sufficiently low alpha may be competitive for such ambitious missions. Topics include Space flight requirements; Spacecraft energy gain; Control theory for performance; Mission assumptions; Round trips: Time and distance; Trip times; Vehicle acceleration; and Minimizing trip times.

  13. Mass balance of the Greenland ice sheet (2003-2008) from ICESat data - the impact of interpolation, sampling and firn density

    DEFF Research Database (Denmark)

    Sørensen, L. S.; Simonsen, Sebastian Bjerregaard; Nielsen, K.;

    2011-01-01

    ICESat has provided surface elevation measurements of the ice sheets since the launch in January 2003, resulting in a unique dataset for monitoring the changes of the cryosphere. Here, we present a novel method for determining the mass balance of the Greenland ice sheet, derived from ICESat...... of the Greenland ice sheet mass balance, based on different remote-sensing techniques....... altimetry data. Three different methods for deriving elevation changes from the ICESat altimetry dataset are used. This multi-method approach provides a method to assess the complexity of deriving elevation changes from this dataset. The altimetry alone can not provide an estimate of the mass balance...

  14. Estimation of groundwater recharge using the chloride mass-balance method, Pingtung Plain, Taiwan

    Science.gov (United States)

    Ting, Cheh-Shyh; Kerh, Tienfuan; Liao, Chiu-Jung

    Due to rapid economic growth in the Pingtung Plain of Taiwan, the use of groundwater resources has changed dramatically. Over-pumping of the groundwater reservoir, which lowers hydraulic heads in the aquifers, is not only affecting the coastal area negatively but has serious consequences for agriculture throughout the plain. In order to determine the safe yield of the aquifer underlying the plain, a reliable estimate of groundwater recharge is desirable. In the present study, for the first time, the chloride mass-balance method is adopted to estimate groundwater recharge in the plain. Four sites in the central part were chosen to facilitate the estimations using the ion-chromatograph and Thiessen polygon-weighting methods. Based on the measured and calculated results, in all sites, including the mountain and river boundaries, recharge to the groundwater is probably 15% of the annual rainfall, excluding recharge from additional irrigation water. This information can improve the accuracy of future groundwater-simulation and management models in the plain. Résumé Du fait de la croissance économique rapide de la plaine de Pingtung à Taiwan, l'utilisation des ressources en eau souterraine s'est considérablement modifié. La surexploitation des aquifères, qui a abaissé le niveau des nappes, n'affecte pas seulement la région côtière, mais a de sérieuses répercutions sur l'agriculture dans toute la plaine. Afin de déterminer les ressources renouvelables de l'aquifère sous la plaine, une estimation précise de la recharge de la nappe est nécessaire. Dans cette étude, le taux de recharge de la nappe a d'abord été estimé au moyen d'un bilan de matière de chlorure. Quatre sites de la partie centrale ont été sélectionnés pour réaliser ces estimations, à l'aide d'un chromatographe ionique et de la méthode des polygones de Thiessen. A partir des résultats mesurés et calculés, à chaque site, et en prenant comme limites les montagnes et les rivi

  15. Dissolved Carbon Flux and Mass Balance From a Wetland-Dominated Karstic Headwater Catchment

    Science.gov (United States)

    Duval, T. P.; Waddington, J. M.; Branfireun, B. A.

    2009-05-01

    The stream-borne dissolved carbon efflux of peatland-draining catchments is dominated by organic carbon, whereas inorganic carbon dominates the flux from calcareous bedrock catchments. The export of dissolved carbon from calcareous bedrock catchments with significant wetland coverage has not previously been determined. This study documents the spatiotemporal variability of dissolved carbon (inorganic + organic) along a headwater stream in southern Ontario, Canada, as it drains three distinct wetland types: a calcareous fen, a riparian cedar swamp, and a cattail marsh. Upon emergence from the groundwater seeps, the spring water contained 28 times more CO2 than in equilibrium with the atmosphere. This supersaturation decreased to just 5 times equilbrium as the stream leaves the catchment through the marsh, representing a decrease in CO2 concentration of 11 mg L-1, lost to the atmosphere as exsolution. The groundwater seeps contained an average of 1.25±0.75 mg L-1 of dissolved organic carbon (DOC) from May to November 2007, one of the driest years on record in the region. At the catchment outlet through the marsh, DOC concentrations were slightly higher and more variable during the same period at 2.27±1.29 mg L-1, as a fall flushing event resulted in concentrations > 7 mg L-1. This DOC concentration is small compared to the 58.72±3.9 mg L-1 of dissolved inorganic carbon (DIC, as bicarbonate ion) contained within the water leaving the catchment. At 0.21 and 0.17 g m-2 d-1 from May-July and August-November 2007, respectively, the DIC dominated the carbon flux out of the watershed, compared with 0.007 and 0.008 g m- 2 d-1 DOC and 0.015 and 0.009 g m-2 d-1 CO2 exsolution during the same period. Results of the 2007 season will be contrasted to the 2008 season, one of the wettest on record. The watershed is underlain by Silurian dolomite that exhibits karst fractures, resulting in a complex subsurface hydrogeology that influences carbon transport and mass balances

  16. Reconnaissance Estimates of Recharge Based on an Elevation-dependent Chloride Mass-balance Approach

    Energy Technology Data Exchange (ETDEWEB)

    Charles E. Russell; Tim Minor

    2002-08-31

    Significant uncertainty is associated with efforts to quantity recharge in arid regions such as southern Nevada. However, accurate estimates of groundwater recharge are necessary to understanding the long-term sustainability of groundwater resources and predictions of groundwater flow rates and directions. Currently, the most widely accepted method for estimating recharge in southern Nevada is the Maxey and Eakin method. This method has been applied to most basins within Nevada and has been independently verified as a reconnaissance-level estimate of recharge through several studies. Recharge estimates derived from the Maxey and Eakin and other recharge methodologies ultimately based upon measures or estimates of groundwater discharge (outflow methods) should be augmented by a tracer-based aquifer-response method. The objective of this study was to improve an existing aquifer-response method that was based on the chloride mass-balance approach. Improvements were designed to incorporate spatial variability within recharge areas (rather than recharge as a lumped parameter), develop a more defendable lower limit of recharge, and differentiate local recharge from recharge emanating as interbasin flux. Seventeen springs, located in the Sheep Range, Spring Mountains, and on the Nevada Test Site were sampled during the course of this study and their discharge was measured. The chloride and bromide concentrations of the springs were determined. Discharge and chloride concentrations from these springs were compared to estimates provided by previously published reports. A literature search yielded previously published estimates of chloride flux to the land surface. {sup 36}Cl/Cl ratios and discharge rates of the three largest springs in the Amargosa Springs discharge area were compiled from various sources. This information was utilized to determine an effective chloride concentration for recharging precipitation and its associated uncertainty via Monte Carlo simulations

  17. Antarctic Ice Sheet Surface Mass Balance Estimates from 2003 TO 2015 Using Icesat and CRYOSAT-2 Data

    Science.gov (United States)

    Xie, Huan; Hai, Gang; Chen, Lei; Liu, Shijie; Liu, Jun; Tong, Xiaohua; Li, Rongxing

    2016-06-01

    An assessment of Antarctic ice sheet surface mass balance from 2003 to 2015 has been carried out using a combination of ICESat data from 2003 to 2009 and CryoSat-2 data from 2010 to 2015. Both data sets are of L2 and are currently processed separately using different models. First, a repeat-track processing method that includes terms accounting for the trend and the first order fit of topography is applied to repeat-track measurements of all ICESat Campaigns. It uses the Least Squares fitting of the model to all observations in a box of 500 m x 500 m. The estimated trends in these boxes are then averaged inside a 30 km x 30 km cell. Similarly, the cells are used to estimate basin and ice sheet level surface elevation change trends. Mass balance calculating is performed at the cell level by multiplying the ice density by the volume change and then extended to the basin and the ice sheet level. Second, in CryoSat-2 data processing we applied a model within a cell of 5 km x 5 km considering that CryoSat-2 does not maintain repeated tracks. In this model the elevation trend, and a higher order topography are solved in an iterative way using the least squares technique. The mass change is computed at the cell level in the same way as the ICESat data. GIA correction is applied for both ICESat and CryoSat-2 estimates. Detailed information about the data processing, elevation and mass balance changes, and comparison with other studies will be introduced.

  18. Mass-balance modelling results of groundwater data collected at Olkiluoto over the period 2004-2007

    International Nuclear Information System (INIS)

    Olkiluoto has been selected as a repository site for final disposal of spent nuclear waste produced in Finland. An understanding of the hydrogeochemical groundwater conditions and their evolution is essential in evaluating the long-term safety of the repository. The performance of technical barriers and the migration of potentially released radionuclides depend on the chemical conditions. A prerequisite for understanding these factors is the ability to specify the water-rock interactions, which control chemical conditions in the groundwater. The objective of this study is to present mass-balance studies of the samples collected over the period 2004 - 2007. A total of 178 groundwater samples have been collected over this period (84 groundwater observation tubes, 88 from deep multipackered boreholes and 6 from the ONKALO) which provided a comprehensive dataset on dissolved chemical species and isotopes. The PHREEQC program was used in the mass-balance calculations in order to develop geochemical interpretations of water-rock interactions, isotope-chemical evolution and the mixing of palaeowater types. A model of the hydrogeochemical evolution in different parts of the crystalline bedrock at Olkiluoto has been created and the significance of chemical reactions and groundwater mixing along different flow paths calculated. The changes in hydrogeochemical interpretations and chemical and isotopic calculations indicate that pH seems to be dominantly controlled by thermodynamic equilibrium with calcite in fractures and there are indications that this process may also occur in the overburden layer. Oxic redox conditions, prevailing in recharging groundwater, change abruptly to sulphidic conditions close to the surface, generally in the overburden. The results from the mass-balance calculations correspond and support the earlier conceptions of groundwater mixing, the origin of salinity and the hydrogeochemical evolution. The fractions of glacial meltwater indicated in these

  19. Assessing the links between Greenland Ice Sheet Surface Mass Balance and Arctic climate using Climate Models and Observations

    Science.gov (United States)

    Mottram, Ruth; Rodehacke, Christian; Boberg, Fredrik; Langen, Peter; Sloth Madsen, Marianne; Høyer Svendsen, Synne; Yang, Shuting; Hesselbjerg Christensen, Jens; Olesen, Martin

    2016-04-01

    Changes in different parts of the Arctic cryosphere may have knock-on effects on other parts of the system. The fully coupled climate model EC-Earth, which includes the ice sheet model PISM, is a useful tool to examine interactions between sea ice, ice sheet, ocean and atmosphere. Here we present results from EC-Earth experimental simulations that show including an interactive ice sheet model changes ocean circulation, sea ice extent and regional climate with, for example, a dampening of the expected increase in Arctic temperatures under the RCP scenarios when compared with uncoupled experiments. However, the relatively coarse resolution of the climate model likely influences the calculated surface mass balance forcing applied to the ice sheet model and it is important therefore to evaluate the model performance over the ice sheet. Here, we assess the quality of the climate forcing from the GCM to the ice sheet model by comparing the energy balance and surface mass balance (SMB) output from EC-Earth with that from a regional climate model (RCM) run at very high resolution (0.05 degrees) over Greenland. The RCM, HIRHAM5, has been evaluated over a wide range of climate parameters for Greenland which allows us to be confident it gives a representative climate forcing for the Greenland ice sheet. To evaluate the internal variability in the climate forcing, we compare simulations from HIRHAM5 forced with both the EC-Earth historical emissions and the ERA-Interim reanalysis on the boundaries. The EC-Earth-PISM RCP8.5 scenario is also compared with an EC-Earth run without an ice sheet to assess the impact of an interactive ice sheet on likely future changes. To account for the resolution difference between the models we downscale both EC-Earth and HIRHAM5 simulations with a simple offline energy balance model (EBM).

  20. Understanding the distribution, degradation and fate of organophosphate esters in an advanced municipal sewage treatment plant based on mass flow and mass balance analysis.

    Science.gov (United States)

    Liang, Kang; Liu, Jingfu

    2016-02-15

    Although organophosphate esters (OPEs) in the ambient environment are from sewage treatment plants due to the discharge of effluent and application of sludge, the distribution, degradation and fate of OPEs in advanced municipal sewage treatment plants remain unclear. This work focused on the use of mass flow and mass balance analysis to understand the behaviors and fate of 14 OPEs in an advanced municipal sewage treatment plant. OPEs were detected in all sewage water and sludge samples with total OPEs (ΣOPEs) concentrations of 1399 ± 263 ng/L in raw sewage aqueous phase, 833 ± 175 ng/L in tertiary effluent aqueous phase, and 315 ± 89 ng/g dry weight in dewatered sludge. The dissolved concentrations of ΣOPEs significantly decreased during biological treatment, whereas negligible decrease was observed in mechanical and physical-chemical treatments. For individual OPE, the chlorinated tris(2-chloroethyl) phosphate (TCEP) and tris(2-chloroisopropyl) phosphate (TCPP) did not decrease but increased during both biological treatment and physical-chemical treatment. Mass flow analysis indicated the total removal efficiency of ΣOPEs in aqueous phase was 40.5%, and the polarity-specific removal efficiencies for individual OPE were positively related to their solid-water partition coefficients (Kd). Furthermore, mass balance results showed that 53.1% and 6.3% of the initial OPE mass flow were eventually transferred to the effluents and dewatered sludge, respectively, while the remaining 39.9% and 0.7% were lost due to biodegradation and physical-chemical treatment, respectively. It was indicated that the activated sludge treatment system with anaerobic/anoxic/aerobic bioreactors was a major factor in the removal of OPEs from the raw sewage, while transfer to dewatered sludge governed by hydrophobic interactions was limited during the sewage treatment. Meanwhile, the degradation difference of OPEs in activated sludge treatment was more related with their molecular

  1. Mass Balance Assessment for Six Neonicotinoid Insecticides During Conventional Wastewater and Wetland Treatment: Nationwide Reconnaissance in United States Wastewater.

    Science.gov (United States)

    Sadaria, Akash M; Supowit, Samuel D; Halden, Rolf U

    2016-06-21

    Occurrence and removal of six high-production high-volume neonicotinoids was investigated in 13 conventional wastewater treatment plants (WWTPs) and one engineered wetland. Flow-weighted daily composites were analyzed by isotope dilution liquid chromatography tandem mass spectrometry, revealing the occurrence of imidacloprid, acetamiprid, and clothianidin at ng/L concentrations in WWTP influent (60.5 ± 40.0; 2.9 ± 1.9; 149.7 ± 289.5, respectively) and effluent (58.5 ± 29.1; 2.3 ± 1.4; 70.2 ± 121.8, respectively). A mass balance showed insignificant removal of imidacloprid (p = 0.09, CI = 95%) and limited removal of the sum of acetamiprid and its degradate, acetamiprid-N-desmethyl (18 ± 4%, p = 0.01, CI = 95%). Clothianidin was found only intermittently, whereas thiamethoxam, thiacloprid, and dinotefuran were never detected. In the wetland, no removal of imidacloprid or acetamiprid was observed. Extrapolation of data from 13 WWTPs to the nation as a whole suggests annual discharges on the order of 1000-3400 kg/y of imidacloprid contained in treated effluent to surface waters nationwide. This first mass balance and first United States nationwide wastewater reconnaissance identified imidacloprid, acetamiprid, and clothianidin as recalcitrant sewage constituents that persist through wastewater treatment to enter water bodies at significant loadings, potentially harmful to sensitive aquatic invertebrates. PMID:27196423

  2. Recent mass balance of the Purogangri Ice Cap, central Tibetan Plateau, by means of differential X-band SAR interferometry

    Directory of Open Access Journals (Sweden)

    N. Neckel

    2013-10-01

    Full Text Available Due to their remoteness, altitude and harsh climatic conditions, little is known about the glaciological parameters of ice caps on the Tibetan Plateau. This study presents a geodetic mass balance estimate of the Purogangri Ice Cap, Tibet's largest ice field between 2000 and 2012. We utilized data from the actual TerraSAR-X mission and its add-on for digital elevation measurements and compared it with elevation data from the Shuttle Radar Topography Mission. The employed data sets are ideal for this approach as both data sets were acquired at X-band at nearly the same time of the year and are available at a fine grid spacing. In order to derive surface elevation changes we employed two different methods. The first method is based on differential synthetic radar interferometry while the second method uses common DEM differencing. Both approaches revealed a slightly negative mass budget of −44 ± 15 and −38 ± 23 mm w.eq. a−1 (millimeter water equivalent respectively. A slightly negative trend of −0.15 ± 0.01 km2 a−1 in glacier extent was found for the same time period employing a time series of Landsat data. Overall, our results show an almost balanced mass budget for the studied time period. Additionally, we detected one continuously advancing glacier tongue in the eastern part of the ice cap.

  3. Sea level changes from monthly solutions of ice sheet mass balance

    DEFF Research Database (Denmark)

    Barletta, Valentina Roberta; Sørensen, Louise Sandberg; Forsberg, René

    We present mass change time series at basin scale for both Greenland and Antarctica, de-rived from GRACE data, and use these data to find the associated global sea level changes. We use two independent methods for GRACE ice mass loss estimation, including use of different GIA models and estimatio...

  4. Changes in the Mass Balance of the Greenland Ice Sheet in a Warming Climate During 2003-2009

    Science.gov (United States)

    Zwally, H. Jay; Luthcke, Scott

    2010-01-01

    Mass changes of the Greenland ice sheet (GIS) derived from ICESat and GRACE data both show that the net mass loss from GIS during 2003-2009 is about 175 Gt/year, which contributes 0.5mm/yr global sea-level rise. The rate of mass loss has increased significantly since the 1990's when the GIS was close to mass balance. Even though the GIS was close to mass balance during the 1990's, it was already showing characteristics of responding to8 warmer climate, specifically thinning at the margins and thickening inland at higher elevations. During 2003-2009, increased ice thinning due to increases in melting and acceleration of outlet glaciers began to strongly exceed the inland thickening from increases in accumulation. Over the entire GIS, the mass loss between the two periods, from increased melting and ice dynamics, increased by about 190 Gt/year while the mass gain, from increased precipitation and accumulation, increased by only about 15Gt/year. These ice changes occurred during a time when the temperature on GIS changed at rate of about 2K/decade. The distribution of elevation and mass changes derived from ICESat have high spatial resolution showing details over outlet glaciers, by drainage systems, and by elevation. However, information on the seasonal cycle of changes from ICESat data is limited, because the ICESat lasers were only operated during two to three campaigns per year of about 35 days duration each. In contrast, the temporal resolution of GRACE data, provided by the continuous data collection, is much better showing details of the seasonal cycle and the inter-annual variability. The differing sensitivity of the ICESat altimetry and the GRACE gravity methods to motion of the underlying bedrock from glacial isostatic adjustment (GIA) is used to evaluate the GIA corrections provided by models. The two data types are also combined to make estimates of the partitioning of the mass gains and losses among accumulation, melting, and ice discharge from outlet

  5. Ocean Basalt Simulator version 1 (OBS1): Trace element mass balance in adiabatic melting of a pyroxenite-bearing peridotite

    Science.gov (United States)

    Kimura, Jun-Ichi; Kawabata, Hiroshi

    2015-01-01

    present a new numerical trace element mass balance model for adiabatic melting of a pyroxenite-bearing peridotite for estimating mantle potential temperature, depth of melting column, and pyroxenite fraction in the source mantle for a primary ocean basalt/picrite. The Ocean Basalt Simulator version 1 (OBS1) uses a thermodynamic model of adiabatic melting of a pyroxenite-bearing peridotite with experimentally/thermodynamically parameterized liquidus-solidus intervals and source mineralogy. OBS1 can be used to calculate a sequence of adiabatic melting with two melting models, including (1) melting of peridotite and pyroxenite sources with simple mixing of their fractional melts (melt-melt mixing model), and (2) pyroxenite melting, melt metasomatism in the host peridotite, and melting of the metasomatized peridotite (source-metasomatism model). OBS1 can be used to explore (1) the fractions of peridotite and pyroxenite, (2) mantle potential temperature, (3) pressure of termination of melting, (4) degree of melting, and (5) residual mode of the sources. In order to constrain these parameters, the model calculates a mass balance for 26 incompatible trace elements in the sources and in the generated basalt/picrite. OBS1 is coded in an Excel spreadsheet and runs with VBA macros. Using OBS1, we examine the source compositions and conditions of the mid-oceanic ridge basalts, Loihi-Koolau basalts in the Hawaiian hot spot, and Jurassic Shatsky Rise and Mikabu oceanic plateau basalts and picrites. The OBS1 model shows the physical conditions, chemical mass balance, and amount of pyroxenite in the source peridotite, which are keys to global mantle recycling.

  6. Quantifying groundwater dependence of a sub-polar lake cluster in Finland using an isotope mass balance approach

    Directory of Open Access Journals (Sweden)

    E. Isokangas

    2014-08-01

    Full Text Available A stable isotope study of 67 kettle lakes and ponds situated on an esker aquifer (90 km2 in northern Finland was carried out in the summer of 2013 to determine the role of groundwater inflow in groundwater-dependent lakes. Distinct seasonal fluctuations in the δ18O and δ2H values of lakes are the result of seasonal ice cover prohibiting evaporation during the winter. An isotope mass balance approach was used to calculate the inflow-to-evaporation ratios (ITOT/E of all 67 lakes during the summer of 2013 when the isotopic compositions of the lakes were approaching a steady-state. The normalised relative humidity needed in this approach came from assuming a terminal lake situation for one of the lakes showing the highest isotope enrichment. Since evaporation rates were derived independently of any mass balance considerations, it was possible to determine the total inflow (ITOT and mean turnover time (MTT of the lakes. Furthermore, the groundwater seepage rates of those lakes revealing no visible surface inflow were calculated. Here, a quantitative measure was introduced for the dependence of a lake on groundwater (G index that is defined as the percentage contribution of groundwater inflow to the total inflow of water to the given lake. The G index values of the lakes studied ranged from 27.8–95.0%, revealing large differences in groundwater dependency among the lakes. This study shows the effectiveness of applying an isotope mass balance approach to quantify the groundwater reliance of lakes situated in a relatively small area with similar climatic conditions.

  7. Use of geomorphic, hydrologic, and nitrogen mass balance data to model ecosystem nitrate retention in tidal freshwater wetlands

    Directory of Open Access Journals (Sweden)

    E. D. Seldomridge

    2012-02-01

    Full Text Available Geomorphic characteristics have been used as scaling parameters to predict water and other fluxes in many systems. In this study, we combined geomorphic analysis with in-situ mass balance studies of nitrate retention (NR to evaluate which geomorphic scaling parameters best predicted NR in a tidal freshwater wetland ecosystem. Geomorphic characteristics were measured for 267 individual marshes that constitute the freshwater tidal wetland ecosystem of the Patuxent River, Maryland. Nitrate retention was determined from mass balance measurements conducted at the inlets of marshes of varying size (671, 5705, and 536 873 m2 over a period of several years. Mass balance measurements indicate that NR is proportional to total water flux over the tidal cycle. Relationships between estimated tidal prism (total water volume for spring tides and various geomorphic parameters (marsh area, total channel length, and inlet width were defined and compared to field data. From these data, NR equations were determined for each geomorphic parameter, and used to estimate NR for all marshes in the ecosystem for a reference spring (high tide. The resulting ecosystem NR estimates were evaluated for: (a accuracy and completeness of geomorphic data, (b relationship between the geomorphic parameters and hydrologic flux, and (c the ability to adapt the geomorphic parameter to varying tidal conditions. This analysis indicated that inlet width data were the most complete and provided the best estimate of ecosystem nitrate retention. Predictions based on marsh area were significantly lower than the inlet width-based predictions. Cumulative probability distributions of nitrate retention indicate that the largest 3–4 % of the marshes retained half of the total nitrate for the ecosystem.

  8. Use of geomorphic, hydrologic, and nitrogen mass balance data to model ecosystem nitrate retention in tidal freshwater wetlands

    Directory of Open Access Journals (Sweden)

    E. D. Seldomridge

    2012-07-01

    Full Text Available Geomorphic characteristics have been used as scaling parameters to predict water and other fluxes in many systems. In this study, we combined geomorphic analysis with in-situ mass balance studies of nitrate retention (NR to evaluate which geomorphic scaling parameters best predicted NR in a tidal freshwater wetland ecosystem. Geomorphic characteristics were measured for 267 individual marshes that constitute the freshwater tidal wetland ecosystem of the Patuxent River, Maryland. Nitrate retention was determined from mass balance measurements conducted at the inlets of marshes of varying size (671, 5705, and 536 873 m2 over a period of several years. Mass balance measurements indicate that NR is proportional to total water flux over the tidal cycle. Relationships between estimated tidal prism (calculated water volume for spring tides and various geomorphic parameters (marsh area, total channel length, and inlet width were defined using measurements from air photos and compared to field data. From these data, NR equations were determined for each geomorphic parameter, and used to estimate NR for all marshes in the ecosystem for a reference spring (high tide. The resulting ecosystem NR estimates were evaluated for (a accuracy and completeness of geomorphic data, (b relationship between the geomorphic parameters and hydrologic flux, and (c the ability to adapt the geomorphic parameter to varying tidal conditions. This analysis indicated that inlet width data were the most complete and provided the best estimate of ecosystem nitrate retention. Predictions based on marsh area were significantly lower than the inlet width-based predictions. Cumulative probability distributions of nitrate retention indicate that the largest 3–4% of the marshes retained half of the total nitrate for the ecosystem.

  9. Mass balance and near-surface ice temperature structure of Baishui Glacier No.1 in Mt.Yulong

    Institute of Scientific and Technical Information of China (English)

    DU Jiankuo; HE Yuanqing; LI Shuang; WANG Shijin; NIU Hewen; XIN Huijuan; PU Tao

    2013-01-01

    The accumulation and ablation of a glacier directly reflect its mass income and wastage,and ice temperature indicates glacier's climatic and dynamic conditions.Glaciological studies at Baishui Glacier No.1 in Mt.Yulong are important for estimating recent changes of the cryosphere in Hengduan Mountains.Increased glacier ablation and higher ice temperatures can cause the incidents of icefall.Therefore,it is important to conduct the study of glacier mass balance and ice temperature,but there are few studies in relation to glacier's mass balance and active-layer temperature in China's monsoonal temperate glacier region.Based on the field observations of mass balance and glacier temperature at Baishui Glacier No.1,its accumulation,ablation,net balance and near-surface ice temperature structure were analyzed and studied in this paper.Results showed that the accumulation period was ranged from October to the following mid-May,and the ablation period occurred from mid-May to October,suggesting that the ablation period of temperate glacier began about 15 days earlier than that of continental glaciers,while the accumulation period began about 15 days later.The glacier ablation rate was 6.47 cm d-1 at an elevation of 4600 m between June 23 and August 30,and it was 7.4 cm d-1 at 4800 m between June 26 and July 11 in 1982,moreover,they respectively increased to 9.2 cm d-1 and 10.8 cm d-1 in the corresponding period and altitude in 2009,indicating that glacier ablation has greatly intensified in the past years.The temperature of the main glacier body was close to melting point in summer,and it dropped from the glacier surface and reached a minimum value at a depth of 4-6 m in the ablation zone.The temperature then rose to around melting point with the depth increment.In winter,the ice temperature rose gradually with the increasing depth,and close to melting point at the depth of 10 m.Compared with the data from 1982,the glacier temperature has risen in the ablation zone in

  10. The Impact of a Mild Sub-Critical Hydrothermal Carbonization Pretreatment on Umbila Wood. A Mass and Energy Balance Perspective

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Cuvilas

    2015-03-01

    Full Text Available Over the last years, the pretreatment of biomass as a source of energy has become one of the most important steps of biomass conversion. In this work the effect of a mild subcritical hydrothermal carbonization of a tropical woody biomass was studied. Results indicate considerable change in carbon content from 52.78% to 65.1%, reduction of oxygen content from 41.14% to 28.72% and ash slagging and fouling potential. Even though decarboxylation, decarbonylation and dehydration reactions take place, dehydration is the one that prevails. The mass and energy balance was affected by the treatment conditions than the severity of the treatment.

  11. A daily, 1-km resolution dataset of downscaled Greenland ice sheet surface mass balance (1958–2015)

    OpenAIRE

    Noël, Brice; Van De Berg, Willem Jan; Machguth, Horst; Lhermitte, Stef; Howat, Ian; Fettweis, Xavier; Broeke, Michiel R.

    2016-01-01

    This study presents a dataset of daily, 1-km resolution Greenland ice sheet (GrIS) surface mass balance (SMB) covering the period 1958–2015. Using elevation dependence, the high-resolution product is statistically downscaled from the native daily output of the polar regional climate model RACMO2.3 at 11-km. The dataset includes all individual SMB components projected to a down-sampled version of the Greenland Ice Mapping Project (GIMP) digital elevation model and ice mask. The 1-km mask...

  12. Indirect measurement of Delta outflow using ultrasonic velocity meters and comparison with mass-balance calculated outflow

    Science.gov (United States)

    Oltmann, Richard N.

    1998-01-01

    A measurement of the quantity of water flowing from the Sacramento-San Joaquin Delta into Suisun Bay (Delta outflow) has been desired by those studying and managing the San Francisco Bay/Delta estuary since the 1920s.  Historically, Delta outflow has been estimated using a mass-balance calculation that uses measured Delta inflows and exports, and imprecise estimates of consumptive use for the approximately 2,000 small agricultural diversions with the Delta.  The DWR has estimated Delta outflow for 1929 to present using the computer program DAYFLOW.

  13. Further Support of the Reliability of the Limit on Photon Mass Given by the Rotating Torsion Balance Experiment

    Institute of Scientific and Technical Information of China (English)

    刘琳霞; 邓罡

    2012-01-01

    We consider there is a vacancy in the plasma in the solar system, and calculate the vector potential produced by the magnetic field frozen in the plasma. The result shows that, in the vacancy, the vector potential produced by the magnetic field frozen in the plasma is much less than the large scale cosmic vector potential. This means if our earth is in such a vacancy, the total vector potential on the surface of the earth is dominated by the cosmic magnetic vector potential, which gives a further support of the reliability of the limit on photon mass given by rotating torsion balance experiment [Phys. Rev. Lett. 90 (2003) 081801].

  14. Development of an in vivo animal model for skin penetration in hairless rats assessed by mass balance

    DEFF Research Database (Denmark)

    Simonsen, Lene; Petersen, Mads B; Benfeldt, Eva;

    2002-01-01

    acid and (14)C-butyl salicylate were topically applied. Rapid and differentiated percutaneous absorption of both compounds were shown by urinary excretion data. For (14)C-salicylic acid the amount on the skin surface, in the stratum corneum and in the viable skin was determined. Total mass balance...... rat and free mobility throughout the test period. By consecutive tape stripping, monitored by measurements of transepidermal water loss and confirmed by histological examination of skin biopsies, 10 tape strippings were found to remove the stratum corneum completely. For assessment of the model, (14)C-salicylic...

  15. Investigating ice cliff evolution and contribution to glacier mass-balance using a physically-based dynamic model

    Science.gov (United States)

    Buri, Pascal; Miles, Evan; Ragettli, Silvan; Brun, Fanny; Steiner, Jakob; Pellicciotti, Francesca

    2016-04-01

    Supraglacial cliffs are a surface feature typical of debris-covered glaciers, affecting surface evolution, glacier downwasting and mass balance by providing a direct ice-atmosphere interface. As a result, melt rates can be very high and ice cliffs may account for a significant portion of the total glacier mass loss. However, their contribution to glacier mass balance has rarely been quantified through physically-based models. Most cliff energy balance models are point scale models which calculate energy fluxes at individual cliff locations. Results from the only grid based model to date accurately reflect energy fluxes and cliff melt, but modelled backwasting patterns are in some cases unrealistic, as the distribution of melt rates would lead to progressive shallowing and disappearance of cliffs. Based on a unique multitemporal dataset of cliff topography and backwasting obtained from high-resolution terrestrial and aerial Structure-from-Motion analysis on Lirung Glacier in Nepal, it is apparent that cliffs exhibit a range of behaviours but most do not rapidly disappear. The patterns of evolution cannot be explained satisfactorily by atmospheric melt alone, and are moderated by the presence of supraglacial ponds at the base of cliffs and by cliff reburial with debris. Here, we document the distinct patterns of evolution including disappearance, growth and stability. We then use these observations to improve the grid-based energy balance model, implementing periodic updates of the cliff geometry resulting from modelled melt perpendicular to the ice surface. Based on a slope threshold, pixels can be reburied by debris or become debris-free. The effect of ponds are taken into account through enhanced melt rates in horizontal direction on pixels selected based on an algorithm considering distance to the water surface, slope and lake level. We use the dynamic model to first study the evolution of selected cliffs for which accurate, high resolution DEMs are available

  16. Climate, glacier mass balance and runoff (1993-2005) for the Mittivakkat Glacier catchment, Ammassalik Island, SE Greenland, and in a long term perspective (1898-1993)

    DEFF Research Database (Denmark)

    Mernild, Sebastian H.; Kane, D.L.; Hansen, Birger;

    2008-01-01

    Climate, glacier mass balance and runoff are investigated in the Low-Arctic Mittivakkat Glacier catchment on Ammassalik Island, Southeast Greenland. High-resolution meteorological data from the catchment covering 1993-2005 and standard synoptic meteorological data from the nearby town of Tasiilaq....... The calculated glacier net mass balance indicates an average glacier loss of 550±530 mm w.eq. yr-1, and 89 out of 105 mass balance years show a negative net mass balance. For the 106-yr period average runoff was estimated to be 1957±254 mm w.eq. yr-1.......Climate, glacier mass balance and runoff are investigated in the Low-Arctic Mittivakkat Glacier catchment on Ammassalik Island, Southeast Greenland. High-resolution meteorological data from the catchment covering 1993-2005 and standard synoptic meteorological data from the nearby town of Tasiilaq...... temperatures (MAAT) occur in the coastal area, indicating an approximately 20-d shorter thawing period. The higher lying glacier area, in contrast, experiences an increasing MAAT, an approximately 40-d longer thawing period and a 60-d longer snow-free period. The Mittivakkat Glacier net mass balance has been...

  17. Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

    Science.gov (United States)

    Engling, G.; He, J.; Betha, R.; Balasubramanian, R.

    2014-08-01

    Biomass burning activities commonly occur in Southeast Asia (SEA), and are particularly intense in Indonesia during the dry seasons. The effect of biomass smoke emissions on air quality in the city state of Singapore was investigated during a haze episode in October 2006. Substantially increased levels of airborne particulate matter (PM) and associated chemical species were observed during the haze period. Specifically, the enhancement in the concentration of molecular tracers for biomass combustion such as levoglucosan by as much as two orders of magnitude and the diagnostic ratios of individual organic compounds indicated that biomass burning emissions caused a regional smoke haze episode due to their long-range transport by prevailing winds. With the aid of air mass backward trajectories and chemical mass balance modeling, large-scale forest and peat fires in Sumatra and Kalimantan were identified as the sources of the smoke aerosol, exerting a significant impact on air quality in downwind areas, such as Singapore.

  18. Assessing the regional impact of Indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

    Directory of Open Access Journals (Sweden)

    G. Engling

    2014-01-01

    Full Text Available Biomass burning activities commonly occur in Southeast Asia (SEA, and are particularly intense in Indonesia during dry seasons. The effect of biomass smoke emissions on air quality in the city state of Singapore was investigated during a haze episode in October 2006. Substantially increased levels of airborne particulate matter (PM and associated chemical species were observed during the haze period. Specifically, the enhancement in the concentration of molecular tracers for biomass combustion such as levoglucosan by as much as two orders of magnitude and diagnostic ratios of individual organic compounds indicated that biomass burning emissions caused a regional smoke haze episode due to their long-range transport by prevailing winds. With the aid of air mass back trajectories and chemical mass balance modeling, large-scale forest and peat fires in Sumatra and Kalimantan were identified as the sources of the smoke aerosol, exerting a significant impact on air quality in downwind areas, such as Singapore.

  19. Effect of GIA models with 3D composite mantle viscosity on GRACE mass balance estimates for Antarctica

    Science.gov (United States)

    van der Wal, Wouter; Whitehouse, Pippa L.; Schrama, Ernst J. O.

    2015-03-01

    Seismic data indicate that there are large viscosity variations in the mantle beneath Antarctica. Consideration of such variations would affect predictions of models of Glacial Isostatic Adjustment (GIA), which are used to correct satellite measurements of ice mass change. However, most GIA models used for that purpose have assumed the mantle to be uniformly stratified in terms of viscosity. The goal of this study is to estimate the effect of lateral variations in viscosity on Antarctic mass balance estimates derived from the Gravity Recovery and Climate Experiment (GRACE) data. To this end, recently-developed global GIA models based on lateral variations in mantle temperature are tuned to fit constraints in the northern hemisphere and then compared to GPS-derived uplift rates in Antarctica. We find that these models can provide a better fit to GPS uplift rates in Antarctica than existing GIA models with a radially-varying (1D) rheology. When 3D viscosity models in combination with specific ice loading histories are used to correct GRACE measurements, mass loss in Antarctica is smaller than previously found for the same ice loading histories and their preferred 1D viscosity profiles. The variation in mass balance estimates arising from using different plausible realizations of 3D viscosity amounts to 20 Gt/yr for the ICE-5G ice model and 16 Gt/yr for the W12a ice model; these values are larger than the GRACE measurement error, but smaller than the variation arising from unknown ice history. While there exist 1D Earth models that can reproduce the total mass balance estimates derived using 3D Earth models, the spatial pattern of gravity rates can be significantly affected by 3D viscosity in a way that cannot be reproduced by GIA models with 1D viscosity. As an example, models with 1D viscosity always predict maximum gravity rates in the Ross Sea for the ICE-5G ice model, however, for one of the three preferred 3D models the maximum (for the same ice model) is found

  20. High-resolution simulations of the surface mass balance of Greenland at the end of this century

    Directory of Open Access Journals (Sweden)

    G. Krinner

    2007-09-01

    Full Text Available We present atmospheric general circulation model simulations of the present (1981–2005 and future (2081–2100 climate according to the SRES A1B greenhouse gas scenario. Focusing on Greenland, we use a stretched grid in the global model, thereby reaching a horizontal grid spacing of 60 km in the region of interest. This allows to capture reasonably the escarpment zone of the ice sheet. For the end of this century, the model suggests a precipitation increase in the central region of Greenland, which is overcompensated for by a strong increase of meltwater production in the lower areas. We calculate the changes of water fluxes into the adjacent seas according the simulated surface mass balances changes. The calculated freshwater flux at the end of the 21st century appears too weak to induce a significant reduction of the meridional overturning circulation in the North Atlantic. The resulting surface mass balance decrease between the last decades of the 20th and 21st centuries is equivalent to a positive contribution of 0.8 mm yr−1 to global eustatic sea-level rise.

  1. On Deriving Requirements for the Surface Mass Balance forcing of a Greenland Ice Sheet Model using Uncertainty Analyses

    Science.gov (United States)

    Schlegel, N.; Larour, E. Y.; Box, J. E.

    2015-12-01

    During July of 2012, the percentage of the Greenland surface exposed to melt was the largest in recorded history. And, even though evidence of increased melt rates had been captured by remote sensing observations throughout the last decade, this particular event took the community by surprise. How Greenland ice flow will respond to such an event or to increased frequencies of extreme melt events in the future is unclear, as it requires detailed comprehension of Greenland surface climate and the ice sheet's sensitivity to associated uncertainties. With established uncertainty quantification (UQ) tools embedded within the Ice Sheet System Model (ISSM), we conduct decadal-scale forward modeling experiments to 1) quantify the spatial resolution needed to effectively force surface mass balance (SMB) in various regions of the ice sheet and 2) determine the dynamic response of Greenland outlet glaciers to variations in SMB. First, we perform sensitivity analyses to determine how perturbations in SMB affect model output; results allow us to investigate the locations where variations most significantly affect ice flow, and on what spatial scales. Next, we apply Monte-Carlo style sampling analyses to determine how errors in SMB propagate through the model as uncertainties in estimates of Greenland ice discharge and regional mass balance. This work is performed at the California Institute of Technology's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration's Cryosphere Program.

  2. Estimating Natural Recharge by Means of Chloride Mass Balance in a Volcanic Aquifer: Northeastern Gran Canaria (Canary Islands, Spain

    Directory of Open Access Journals (Sweden)

    Gema Naranjo

    2015-05-01

    Full Text Available The chloride mass balance method was used to estimate the average diffuse groundwater recharge on northeastern Gran Canaria (Canary Islands, where the largest recharge to the volcanic island aquifer occurs. Rainwater was sampled monthly in ten rainwater collectors to determine the bulk deposition rate of chloride for the 2008–2014 period. Average chloride deposition decreases inwardly from more than 10 g·m−2·year−1 to about 4 g·m−2·year−1. The application of the chloride mass balance method resulted in an estimated average recharge of about 28 hm3/year or 92 mm/year (24% of precipitation in the study area after subtracting chloride loss with surface runoff. The average storm runoff was estimated to be 12 hm3/year (9% of precipitation for the 1980–2014 period. Runoff was sampled during scarce rainy periods, which produce surface water flow. Average recharge varies from less than a few mm/year near the coast up to 270 mm/year in the highlands (about 33% of average rainfall, with a close-to-linear increase inwardly of about 18 mm·year−1·km−1. Recharge rate uncertainty corresponds to an estimated CV of 0.3–0.4 because of the short data series available.

  3. Comparison of mass balance, energy consumption and cost of composting facilities for different types of organic waste

    International Nuclear Information System (INIS)

    Mass balance, energy consumption and cost are basic pieces of information necessary for selecting a waste management technology. In this study, composting facilities that treat different types of organic waste were studied by questionnaire survey and via a chemical analysis of material collected at the facilities. The mass balance was calculated on a dry weight basis because the moisture content of organic waste was very high. Even though the ratio of bulking material to total input varied in the range 0-65% on a dry basis, the carbon and ash content, carbon/nitrogen ratio, heavy metal content and inorganic nutrients in the compost were clearly influenced by the different characteristics of the input waste. The use of bulking material was not correlated with ash or elemental content in the compost. The operating costs were categorised into two groups. There was some economy of scale for wages and maintenance cost, but the costs for electricity and fuel were proportional to the amount of waste. Differences in operating costs can be explained by differences in the process characteristics.

  4. A mass balance approach to the fate of viruses in a municipal wastewater treatment plant during summer and winter seasons.

    Science.gov (United States)

    Ulbricht, Katharina; Selinka, Hans-Christoph; Wolter, Stefanie; Rosenwinkel, Karl-Heinz; Nogueira, Regina

    2014-01-01

    In contrast to previous discussion on general virus removal efficiency and identifying surrogates for human pathogenic viruses, this study focuses on virus retention within each step of a wastewater treatment plant (WWTP). Additionally, the influence of weather conditions on virus removal was addressed. To account for the virus retention, this study describes a mass balance of somatic coliphages (bacterial viruses) in a municipal WWTP, performed in the winter and summer seasons of 2011. In the winter season, the concentration of coliphages entering the WWTP was about 1 log lower than in summer. The mass balance in winter revealed a virus inactivation of 85.12 ± 13.97%. During the summer season, virus inactivation was significantly higher (95.25 ± 3.69%, p-value <0.05), most likely due to additional virus removal in the secondary clarifier by insolation. Thus, a total removal of coliphages of about 2.78 log units was obtained in summer compared to 1.95 log units in winter. Rainfall events did not statistically correlate with the concentrations of coliphages entering the WWTP in summer. PMID:24473307

  5. Calculating carbon mass balance from unsaturated soil columns treated with CaSO₄₋minerals: test of soil carbon sequestration.

    Science.gov (United States)

    Han, Young-Soo; Tokunaga, Tetsu K

    2014-12-01

    Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment.

  6. Balanced conditions or slight mass gain of glaciers in the Lahaul and Spiti region (northern India, Himalaya during the nineties preceded recent mass loss

    Directory of Open Access Journals (Sweden)

    C. Vincent

    2013-04-01

    Full Text Available The volume change of the Chhota Shigri Glacier (India, 32° 20 N, 77° 30' E between 1988 and 2010 has been determined using in situ geodetic measurements. This glacier has experienced only a slight mass loss between 1988 and 2010 (−3.8 ± 2.0 m w.e. (water equivalent corresponding to −0.17 ± 0.09 m w.e. yr−1. Using satellite digital elevation models (DEM differencing and field measurements, we measure a negative mass balance (MB between 1999 and 2010 (−4.8 ± 1.8 m w.e. corresponding to −0.44 ± 0.16 m w.e. yr−1. Thus, we deduce a slightly positive or near-zero MB between 1988 and 1999 (+1.0 ± 2.7 m w.e. corresponding to +0.09 ± 0.24 m w.e. yr−1. Furthermore, satellite DEM differencing reveals that the MB of the Chhota Shigri Glacier (−0.39 ± 0.15 m w.e. yr−1 has been only slightly less negative than the MB of a 2110 km2 glaciarized area in the Lahaul and Spiti region (−0.44 ± 0.09 m w.e. yr−1 during 1999−2011. Hence, we conclude that the ice wastage is probably moderate in this region over the last 22 yr, with near equilibrium conditions during the nineties, and an ice mass loss after. The turning point from balanced to negative mass budget is not known but lies probably in the late nineties and at the latest in 1999. This positive or near-zero MB for Chhota Shigri Glacier (and probably for the surrounding glaciers of the Lahaul and Spiti region during at least part of the 1990s contrasts with a recent compilation of MB data in the Himalayan range that indicated ice wastage since 1975. However, in agreement with this compilation, we confirm more negative balances since the beginning of the 21st century.

  7. Model of operating and balancing assembly line in a mass customization environment

    Institute of Scientific and Technical Information of China (English)

    Wei Dong; Jin Ye; Wang Rong; Wang Zheng

    2003-01-01

    The successful implementation of mass customization lies on reengineering technology and management methods to organize the production. Especially in assembly phase, various product con figurations, due-time penalties and order-driven strategy challenge the traditional operation and man agement of assembly lines. The business features and the operation pattern of assembly line based on mass customization are analyzed. And the research emphatically studies various technologic factors to improve customer satisfaction and their corresponding implement methods in operating assembly line.In addition, the models are proposed for operating assembly line under dynamic process environment in mass customization. A genetic approach is developed to provide the optimal solution to the models.The effectiveness of the proposed approach is evaluated with an industrial application.

  8. The use of mass and energy balances for observation in process plant diagnosis

    International Nuclear Information System (INIS)

    A method is described that uses the invariant mass and energy conservation laws in order to extract a detailed pattern of mass and energy flows from the instrumentation of a process plant. The basic feature of the method is that it is applicable to a large range of plant operational situations, such as those initiated by unforeseen failures during sequential operations. The authors' intensions with this interim progress report are to describe the basic ideas behind the method, as well as to discuss some of its implications for man-computer cooperation in process plant diagnosis. (author)

  9. Estimation of glacier mass balance: An approach based on satellite-derived transient snowlines and a temperature index driven by meteorological observations

    Science.gov (United States)

    Tawde, S. A.; Kulkarni, A. V.; Bala, G.

    2015-12-01

    In the Himalaya, large area is comprised of glaciers and seasonal snow, mainly due to its high elevated mountain ranges. Long term and continuous assessment of glaciers in this region is important for climatological and hydrological applications. However, rugged terrains and severe weather conditions in the Himalaya lead to paucity in field observations. Therefore, in recent decades, glacier dynamics are extensively monitored using remote sensing in inaccessible terrain like Himalaya. Estimation of glacier mass balance using empirical relationship between mass balance and area accumulation ratio (AAR) requires an accurate estimate of equilibrium-line altitude (ELA). ELA is defined as the snowline at the end of the hydrological year. However, identification of ELA, using remote sensing is difficult because of temporal gaps, cloud cover and intermediate snowfall on glaciers. This leads to large uncertainty in glacier mass-balance estimates by the conventional AAR method that uses satellite-derived highest snowline in ablation season as an ELA. The present study suggests a new approach to improve estimates of ELA location. First, positions of modelled snowlines are optimized using satellite-derived snowlines in the early melt season. Secondly, ELA at the end of the glaciological year is estimated by the melt and accumulation models driven using in situ temperature and precipitation records. From the modelled ELA, mass balance is estimated using the empirical relationship between AAR and mass balance. The modelled mass balance is validated using field measurements on Chhota Shigri and Hamtah glaciers, Himachal Pradesh, India. The new approach shows a substantial improvement in glacier mass-balance estimation, reducing bias by 46% and 108% for Chhota Shigiri and Hamtah glaciers respectively. The cumulative mass loss reconstructed from our approach is 0.85 Gt for nine glaciers in the Chandra basin from 2001 to 2009. The result of the present study is in agreement with

  10. Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA)

    Science.gov (United States)

    Jepsen, S.M.; Voss, C.I.; Walvoord, M.A.; Rose, J.R.; Minsley, B.J.; Smith, B.D.

    2013-01-01

    Many lakes in northern high latitudes have undergone substantial changes in surface area over the last four decades, possibly as a result of climate warming. In the discontinuous permafrost of Yukon Flats, interior Alaska (USA), these changes have been non-uniform across adjacent watersheds, suggesting local controls on lake water budgets. Mechanisms that could explain the decreasing mass of one lake in Yukon Flats since the early 1980s, Twelvemile Lake, are identified via a scoping analysis that considers plausible changes in snowmelt mass and infiltration, permafrost distribution, and climate warming. Because predicted changes in evaporation (2 cmyr-1) are inadequate to explain the observed 17.5 cmyr-1 reduction in mass balance, other mechanisms are required. The most important potential mechanisms are found to involve: (1) changes in shallow, lateral groundwater flow to the lake possibly facilitated by vertical freeze-thaw migration of the permafrost table in gravel; (2) increased loss of lake water as downward groundwater flow through an open talik to a permeable subpermafrost flowpath; and (3) reduced snow meltwater inputs due to decreased snowpack mass and increased infiltration of snowmelt into, and subsequent evaporation from, fine-grained sediment mantling the permafrost-free lake basin.

  11. New Balancing Equipment for Mass Production of Small and Medium-Sized Electrical Machines

    DEFF Research Database (Denmark)

    Argeseanu, Alin; Ritchie, Ewen; Leban, Krisztina Monika

    2010-01-01

    The level of vibration and noise is an important feature. It is good practice to explain the significance of the indicators of the quality of electrical machines. The mass production of small and medium-sized electrical machines demands speed (short typical measurement time), reliability...

  12. Analysis of Antarctic Ice-Sheet Mass Balance from ICESat Measurements

    Science.gov (United States)

    Zwally, H. Jay; Li, Jun; Robbins, John; Saba, Jack L.; Yi, Donghui

    2011-01-01

    If protoplanets formed from 10 to 20 kilometer diameter planetesimals in a runaway accretion process prior to their oligarchic growth into the terrestrial planets, it is only logical to ask where these planetesimals may have formed in order to assess the initial composition of the Earth. We have used Weidenschilling's model for the formation of comets (1997) to calculate an efficiency factor for the formation of planetesimals from the solar nebula, then used this factor to calculate the feeding zones that contribute to material contained within 10, 15 and 20 kilometer diameter planetesimals at 1 A.V. as a function of nebular mass. We find that for all reasonable nebular masses, these planetesimals contain a minimum of 3% water as ice by mass. The fraction of ice increases as the planetesimals increase in size and as the nebular mass decreases, since both factors increase the feeding zones from which solids in the final planetesimals are drawn. Is there really a problem with the current accretion scenario that makes the Earth too dry, or is it possible that the nascent Earth lost significant quantities of water in the final stages of accretion?

  13. TBP and diluent mass balances in the PUREX Plant at Hanford, 1955--1991

    International Nuclear Information System (INIS)

    The purpose of this report is to develop an estimate of the quantities of tributyl phosphate and diluent discharged in aqueous waste streams to the tank farms from the Hanford Purex Plant over its operating life. Purex was not the sole source of organics in the tank farms, but was a major contributor. Tributyl phosphate (TBP) and diluent, which changed from Shell E-2342 reg-sign to Soltrol-170 reg-sign and then to normal paraffin hydrocarbon (NPH), were organic chemicals used in the Purex solvent extraction process at Hanford to separate plutonium and uranium from spent nuclear fuels. This report is an estimate of the material balances for these chemicals in the Purex Plant at Hanford over its entire operating life. The Purex Plant had cold start up in November 1955 and shut down in 1990. It's process used a solution of 30 vol% TBP in diluent

  14. Reconstruction of the 1979–2006 Greenland ice sheet surface mass balance using the regional climate model MAR

    Directory of Open Access Journals (Sweden)

    X. Fettweis

    2007-10-01

    Full Text Available Results from a 28-year simulation (1979–2006 over the Greenland ice sheet (GrIS reveal an increase of solid precipitation (+0.4±2.5 km3 yr−2 and run-off (+7.9±3.3 km3 yr−2 of surface meltwater. The net effect of these competing factors is a significant Surface Mass Balance (SMB loss of −7.2±5.1 km3 yr−2. The contribution of changes in the net water vapour flux (+0.02±0.09 km3 yr−2 and rainfall (+0.2±0.2 km3 yr−2 to the SMB variability is negligible. The meltwater supply has increased because the GrIS surface has been warming up +2.4°C since 1979. Sensible heat flux, latent heat flux and net solar radiation have not varied significantly over the last three decades. However, the simulated downward infrared flux has increased by 9.3 W m−2 since 1979. The natural climate variability (e.g. the North Atlantic Oscillation does not explain these changes. The recent global warming, due to the greenhouse gas concentration increase induced by human activities, could be a cause of these changes. The doubling of surface meltwater flux into the ocean over the period 1979–2006 suggests that the overall ice sheet mass balance has been increasingly negative, given the likely meltwater-induced acceleration of outlet glaciers. This study suggests that increased melting overshadows over an increased accumulation in a warming scenario and that the GrIS is likely to keep losing mass in the future. An enduring GrIS melting will probably affect in the future an certain effect on the stability of the thermohaline circulation and the global sea level rise.

  15. Reconstruction of the 1979–2006 Greenland ice sheet surface mass balance using the regional climate model MAR

    Directory of Open Access Journals (Sweden)

    X. Fettweis

    2007-07-01

    Full Text Available Results from a 28-year simulation (1979–2006 over the Greenland ice sheet (GIS reveal an increase of the solid precipitation (+0.4±2.5 km3 yr−2 and the run-off (+7.9±3.3 km3 yr−2 of surface melt water. The net effect of these competing factors leads to a significant Surface Mass Balance (SMB loss rate of −7.2±5.1 km3 yr−2. The contribution of changes in the net water vapour fluxes (+0.02±0.09 km3 yr−2 and rainfall (+0.2±0.2 km3 yr−2 to the SMB variability is negligible. The melt water supply has increased because the GIS surface has been warming up +2.4°C since 1979. Latent heat flux, sensible heat flux and net solar radiation have not varied significantly over the last three decades. However, the simulated downward infra-red flux has increased by 9.3 W m−2 since 1979. The natural climate variability (e.g. the North Atlantic Oscillation does not explain these changes on the GIS. The recent global warming, due to the greenhouse gas concentration increase induced by the human activities, could be a cause of these changes. The doubling of the surface melt water flux into the ocean over the period 1979–2006 suggests that the overall ice sheet mass balance has been increasingly negative, given the probable meltwater-induced outlet glacier acceleration. This study suggests that an increased melting dominates over an increased accumulation in a warming scenario and that the GIS would likely continue to loose mass in the future. A GIS melting would have an effect on the stability of the thermohaline circulation (THC and the global sea level rise.

  16. Mass Balance of the Northern Antarctic Peninsula and its Ongoing Response to Ice Shelf Loss

    Science.gov (United States)

    Scambos, T. A.; Berthier, E.; Haran, T. M.; Shuman, C. A.; Cook, A. J.; Bohlander, J. A.

    2012-12-01

    An assessment of the most rapidly changing areas of the Antarctic Peninsula (north of 66°S) shows that ice mass loss for the region is dominated by areas affected by eastern-Peninsula ice shelf losses in the past 20 years. Little if any of the mass loss is compensated by increased snowfall in the northwestern or far northern areas. We combined satellite stereo-image DEM differencing and ICESat-derived along-track elevation changes to measure ice mass loss for the Antarctic Peninsula north of 66°S between 2001-2010, focusing on the ICESat-1 period of operation (2003-2009). This mapping includes all ice drainages affected by recent ice shelf loss in the northeastern Peninsula (Prince Gustav, Larsen Inlet, Larsen A, and Larsen B) as well as James Ross Island, Vega Island, Anvers Island, Brabant Island and the adjacent west-flowing glaciers. Polaris Glacier (feeding the Larsen Inlet, which collapsed in 1986) is an exception, and may have stabilized. Our method uses ASTER and SPOT-5 stereo-image DEMs to determine dh/dt for elevations below 800 m; at higher elevations ICESat along-track elevation differencing is used. To adjust along-track path offsets between its 2003-2009 campaigns, we use a recent DEM of the Peninsula to establish and correct for cross-track slope (Cook et al., 2012, doi:10.5194/essdd-5-365-2012; http://nsidc.org/data/nsidc-0516.html) . We reduce the effect of possible seasonal variations in elevation by using only integer-year repeats of the ICESat tracks for comparison. Mass losses are dominated by the major glaciers that had flowed into the Prince Gustav (Boydell, Sjorgren, Röhss), Larsen A (Edgeworth, Bombardier, Dinsmoor, Drygalski), and Larsen B (Hektoria, Jorum, and Crane) embayments. The pattern of mass loss emphasizes the significant and multi-decadal response to ice shelf loss. Areas with shelf losses occurring 30 to 100s of years ago seem to be relatively stable or losing mass only slowly (western glaciers, northernmost areas). The

  17. Problems of the rotating-torsion-balance limit on the photon mass

    OpenAIRE

    Goldhaber, Alfred Scharff; Nieto, Michael Martin

    2003-01-01

    We discuss the problems (and the promise) of the ingenious method introduced by Lakes, and recently improved on by Luo, to detect a possible small photon mass $\\mu$ by measuring the ambient magnetic vector potential from large scale magnetic fields. We also point out how an improved ``indirect'' limit can be obtained using modern measurements of astrophysical magnetic fields and plasmas and that a good ``direct'' limit exists using properties of the solar wind.

  18. Thickening and Thinning of Antarctic Ice Shelves and Tongues and Mass Balance Estimates

    Science.gov (United States)

    Zwally, H. Jay; Li, Jun; Giovinetto, Mario; Robbins, John; Saba, Jack L.; Yi, Donghui

    2011-01-01

    Previous analysis of elevation changes for 1992 to 2002 obtained from measurements by radar altimeters on ERS-l and 2 showed that the shelves in the Antarctic Peninsula (AP) and along the coast of West Antarctica (WA), including the eastern part of the Ross Ice Shelf, were mostly thinning and losing mass whereas the Ronne Ice shelf also in WA was mostly thickening. The estimated total mass loss for the floating ice shelves and ice tongues from ice draining WA and the AP was 95 Gt/a. In contrast, the floating ice shelves and ice tongues from ice draining East Antarctica (EA), including the Filchner, Fimbul, Amery, and Western Ross, were mostly thickening with a total estimated mass gain of 142 Gt/a. Data from ICESat laser altimetry for 2003-2008 gives new surface elevation changes (dH/dt) with some similar values for the earlier and latter periods, including -27.6 and -26.9 cm a-Ion the West Getz ice shelf and -42.4 and - 27.2 cm/a on the East Getz ice shelf, and some values that indicate more thinning in the latter period, including -17.9 and -36.2 cm/a on the Larsen C ice shelf, -35.5 and -76.0 cm/a on the Pine Island Glacier floating, -60.5 and -125.7 .cm/a on the Smith Glacier floating, and -34.4 and -108.9 cm/a on the Thwaites Glacier floating. Maps of measured dH/dt and estimated thickness change are produced along with mass change estimates for 2003 - 2008.

  19. On the Mathematical Structure of Balanced Chemical Reaction Networks Governed by Mass Action Kinetics

    OpenAIRE

    der Schaft, Arjan van; Rao, Shodhan; Jayawardhana, Bayu

    2011-01-01

    Motivated by recent progress on the interplay between graph theory, dynamics, and systems theory, we revisit the analysis of chemical reaction networks described by mass action kinetics. For reaction networks possessing a thermodynamic equilibrium we derive a compact formulation exhibiting at the same time the structure of the complex graph and the stoichiometry of the network, and which admits a direct thermodynamical interpretation. This formulation allows us to easily characterize the set ...

  20. Vanadium methyl-bipyridine organoligand and its influence on energy balance and organs mass.

    Science.gov (United States)

    Krośniak, Mirosław; Francik, Renata; Wojtanowska-Krośniak, Agnieszka; Tedeschi, Cinzia; Krasoń-Nowak, Małgorzata; Chłopicka, Joanna; Gryboś, Ryszard

    2014-09-01

    In the treatment of lifestyle diseases, including metabolic syndrome and type 2 diabetes, it is important to lower body mass and fat tissue, and consequently, to increase insulin-sensitivity. Unfortunately, it often happens that low-energy diet which would lower overweight is not observed and, thus, it does not bring the expected effects. This paper discusses the influence of three diets-control, high-fructose, and high-fatty diet-on absorption of energy from food in order to transform it into body mass. The kJ/g ratio which describes this process has been calculated. In the tested diets, the addition of fructose (79.13 ± 2.47 kJ/g) or fat (82.48 ± 2.28 kJ/g) results in higher transformation of energy into body mass than in the case of control diet (89.60 ± 1.86 kJ/g). The addition of Na[VO(O2)2(4,4′-Me2-2,2′-bpy)]•8H2O (where 4,4′-Me2-2,2′-bpy = 4,4′-dimethyl-2,2′-bipyridine) results in statistical increase of that ratio: fructose diet (86.88 ± 0.44 kJ/g), fat diet (104.68 ± 3.01 kJ/g), and control diet (115.98 ± 0.56 kJ/g), respectively. Fat diet statistically influences the decrease of kidney mass in comparison to the other diets. The application of the tested vanadium compound results also in the statistical decrease of the fatty liver caused by fructose and fat diet.

  1. Using bioprocess stoichiometry to build a plant-wide mass balance based steady-state WWTP model.

    Science.gov (United States)

    Ekama, G A

    2009-05-01

    Steady-state models are useful for design of wastewater treatment plants (WWTPs) because they allow reactor sizes and interconnecting flows to be simply determined from explicit equations in terms of unit operation performance criteria. Once the overall WWTP scheme is established and the main system defining parameters of the individual unit operations estimated, dynamic models can be applied to the connected unit operations to refine their design and evaluate their performance under dynamic flow and load conditions. To model anaerobic digestion (AD) within plant-wide WWTP models, not only COD and nitrogen (N) but also carbon (C) fluxes entering the AD need to be defined. Current plant-wide models, like benchmark simulation model No 2 (BSM2), impose a C flux at the AD influent. In this paper, the COD and N mass balance steady-state models of activated sludge (AS) organics degradation, nitrification and denitrification (ND) and anaerobic (AD) and aerobic (AerD) digestion of wastewater sludge are extended and linked with bioprocess transformation stoichiometry to form C, H, O, N, chemical oxygen demand (COD) and charge mass balance based models so that also C (and H and O) can be tracked through the whole WWTP. By assigning a stoichiometric composition (x, y, z and a in C(x)H(y)O(z)N(a)) to each of the five main influent wastewater organic fractions and ammonia, these, and the products generated from them via the biological processes, are tracked through the WWTP. The model is applied to two theoretical case study WWTPs treating the same raw wastewater (WW) to the same final sludge residual biodegradable COD. It is demonstrated that much useful information can be generated with the relatively simple steady-state models to aid WWTP layout design and track the different products exiting the WWTP via the solid, liquid and gas streams, such as aerobic versus anaerobic digestion of waste activated sludge, N loads in recycle streams, methane production for energy recovery

  2. Mass balance evaluation of polybrominated diphenyl ethers in landfill leachate and potential for transfer from e-waste.

    Science.gov (United States)

    Danon-Schaffer, Monica N; Mahecha-Botero, Andrés; Grace, John R; Ikonomou, Michael

    2013-09-01

    Previous research on brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) has largely focussed on their concentrations in the environment and their adverse effects on human health. This paper explores their transfer from waste streams to water and soil. A comprehensive mass balance model is developed to track polybrominated diphenyl ethers (PBDEs), originating from e-waste and non-e-waste solids leaching from a landfill. Stepwise debromination is assumed to occur in three sub-systems (e-waste, aqueous leachate phase, and non-e-waste solids). Analysis of landfill samples and laboratory results from a solid-liquid contacting chamber are used to estimate model parameters to simulate an urban landfill system, for past and future scenarios. Sensitivity tests to key model parameters were conducted. Lower BDEs require more time to disappear than high-molecular weight PBDEs, since debromination takes place in a stepwise manner, according to the simplified reaction scheme. Interphase mass transfer causes the decay pattern to be similar in all three sub-systems. The aqueous phase is predicted to be the first sub-system to eliminate PBDEs if their input to the landfill were to be stopped. The non-e-waste solids would be next, followed by the e-waste sub-system. The model shows that mass transfer is not rate-limiting, but the evolution over time depends on the kinetic degradation parameters. Experimental scatter makes model testing difficult. Nevertheless, the model provides qualitative understanding of the influence of key variables.

  3. Geochemical mass balance and elemental transport during the weathering of the black shale of Shuijingtuo formation in Northeast Chongqing, China.

    Science.gov (United States)

    Ling, Sixiang; Wu, Xiyong; Zhao, Siyuan; Liao, Xin; Ren, Yong; Zhu, Baolong

    2014-01-01

    An understanding of the processes that control the behavior of major elements with respect to weathering profile is essential to calculate the mobility, redistribution, and mass fluxes of elements. Hence, this study aims to determine the geochemical mass balance, strain, elemental correlation, and transport in weathering profiles. We constructed three weathering profiles for the black shale of Shujingtuo formation. As per the principal component analysis of major elements, density, and pH values, the first component represents the "elemental factor" and the second denotes the "external factor." The "depletion" pattern is a mass transportation pattern, and Na, K, and Mg are depleted along transect relative to the composition of fresh rock. Fe is redeposited at the bottom half of the saprock zone, whereas Al is accumulated at the regolith zone. The Fe and Al patterns are attributed to the "depletion-addition" and "addition" patterns, respectively. The strain in profiles A and B demonstrates the expansion at the regolith zone and part of the saprock zone. In profile C, however, these zones collapsed at all depths. In chemical weathering, Na, K, Ca, Mg, and Si are depleted in the following order: valley (C) > near mountaintop (B) > ridge (A).

  4. Geochemical Mass Balance and Elemental Transport during the Weathering of the Black Shale of Shuijingtuo Formation in Northeast Chongqing, China

    Directory of Open Access Journals (Sweden)

    Sixiang Ling

    2014-01-01

    Full Text Available An understanding of the processes that control the behavior of major elements with respect to weathering profile is essential to calculate the mobility, redistribution, and mass fluxes of elements. Hence, this study aims to determine the geochemical mass balance, strain, elemental correlation, and transport in weathering profiles. We constructed three weathering profiles for the black shale of Shujingtuo formation. As per the principal component analysis of major elements, density, and pH values, the first component represents the “elemental factor” and the second denotes the “external factor.” The “depletion” pattern is a mass transportation pattern, and Na, K, and Mg are depleted along transect relative to the composition of fresh rock. Fe is redeposited at the bottom half of the saprock zone, whereas Al is accumulated at the regolith zone. The Fe and Al patterns are attributed to the “depletion–addition” and “addition” patterns, respectively. The strain in profiles A and B demonstrates the expansion at the regolith zone and part of the saprock zone. In profile C, however, these zones collapsed at all depths. In chemical weathering, Na, K, Ca, Mg, and Si are depleted in the following order: valley (C > near mountaintop (B > ridge (A.

  5. Evolution of the Digital Society Reveals Balance between Viral and Mass Media Influence

    Science.gov (United States)

    Kleineberg, Kaj-Kolja; Boguñá, Marián

    2014-07-01

    Online social networks (OSNs) enable researchers to study the social universe at a previously unattainable scale. The worldwide impact and the necessity to sustain the rapid growth of OSNs emphasize the importance of unraveling the laws governing their evolution. Empirical results show that, unlike many real-world growing networked systems, OSNs follow an intricate path that includes a dynamical percolation transition. In light of these results, we present a quantitative two-parameter model that reproduces the entire topological evolution of a quasi-isolated OSN with unprecedented precision from the birth of the network. This allows us to precisely gauge the fundamental macroscopic and microscopic mechanisms involved. Our findings suggest that the coupling between the real preexisting underlying social structure, a viral spreading mechanism, and mass media influence govern the evolution of OSNs. The empirical validation of our model, on a macroscopic scale, reveals that virality is 4-5 times stronger than mass media influence and, on a microscopic scale, individuals have a higher subscription probability if invited by weaker social contacts, in agreement with the "strength of weak ties" paradigm.

  6. Cloud effects on surface energy and mass balance in the ablation area of Brewster Glacier, New Zealand

    Science.gov (United States)

    Conway, J. P.; Cullen, N. J.

    2016-02-01

    The effect of clouds on glacier surface energy balance (SEB) has received increased attention in the last decade, but how clouds interact with other meteorological forcing to influence surface mass balance (SMB) is not as well understood. This paper resolves the SEB and SMB at a site in the ablation zone of Brewster Glacier over a 22-month period, using high-quality radiation data to carefully evaluate SEB terms and define clear-sky and overcast conditions. A fundamental change in glacier SEB in cloudy conditions was driven by increased effective sky emissivity and surface vapour pressure, rather than a minimal change in air temperature and wind speed. During overcast conditions, positive net long-wave radiation and latent heat fluxes allowed melt to be maintained through a much greater length of time compared to clear-sky conditions, and led to similar melt in each sky condition. The sensitivity of SMB to changes in air temperature was greatly enhanced in overcast compared to clear-sky conditions due to more frequent melt and changes in precipitation phase that created a strong albedo feedback. During the spring and autumn seasons, the sensitivity during overcast conditions was strongest. To capture these processes, future attempts to explore glacier-climate interactions should aim to resolve the effects of atmospheric moisture (vapour, cloud, and precipitation) on melt as well as accumulation, through enhanced statistical or physically based methods.

  7. Efficient fractionation of spruce by SO(2)-ethanol-water treatment: closed mass balances for carbohydrates and sulfur.

    Science.gov (United States)

    Iakovlev, Mikhail; van Heiningen, Adriaan

    2012-08-01

    SO(2)-ethanol-water (SEW) lignocellulosic fractionation has the potential to overcome the present techno-economic barriers that hinder the commercial implementation of renewable transportation fuel production. In this study, SEW fractionation of spruce wood chips is examined for its ability to separate the main wood components, hemicelluloses, lignin, and cellulose, and the potential to recover SO(2) and ethanol from the spent fractionation liquid. Therefore, overall sulfur and carbohydrate mass balances are established. 95-97 % of the charged SO(2) remains in the liquid and can be fully recovered by distillation. During fractionation, hemicelluloses and lignin are effectively dissolved, whereas cellulose is preserved in the solid (fibre) phase. Hemicelluloses are hydrolysed, producing up to 50 % monomeric sugars, whereas dehydration and oxidation of carbohydrates are insignificant. The latter is proven by the closed carbohydrate material balances as well as by the near absence of corresponding by-products (furfural, hydroxymethylfurfural (HMF) and aldonic acids). In addition, acid methanolysis/GC and acid hydrolysis/high performance anion exchange chromatography (HPAEC) methods for the carbohydrate determination are compared. PMID:22740146

  8. Effect of body mass and melanism on heat balance in Liolaemus lizards of the goetschi clade.

    Science.gov (United States)

    Moreno Azócar, Débora Lina; Bonino, Marcelo Fabián; Perotti, María Gabriela; Schulte, James A; Abdala, Cristian Simón; Cruz, Félix Benjamín

    2016-04-15

    The body temperature of ectotherms depends on the environmental temperatures and behavioral adjustments, but morphology may also have an effect. For example, in colder environments, animals tend to be larger and to show higher thermal inertia, as proposed by Bergmann's rule and the heat balance hypothesis (HBH). Additionally, dark coloration increases solar radiation absorption and should accelerate heat gain (thermal melanism hypothesis, TMH). We tested Bergmann's rule, the HBH and the TMH within the ITALIC! Liolaemus goetschilizard clade, which shows variability in body size and melanic coloration. We measured heating and cooling rates of live and euthanized animals, and tested how morphology and color affect these rates. Live organisms show less variable and faster heating rates compared with cooling rates, suggesting behavioral and/or physiological adjustments. Our results support Bergmann's rule and the HBH, as larger species show slower heating and cooling rates. However, we did not find a clear pattern to support the TMH. The influence of dorsal melanism on heating by radiation was masked by the body size effect in live animals, and results from euthanized individuals also showed no clear effects of melanism on heating rates. Comparison among three groups of live individuals with different degrees of melanism did not clarify the influence of melanism on heating rates. However, when euthanized animals from the same three groups were compared, we observed that darker euthanized animals actually heat faster than lighter ones, favoring the TMH. Although unresolved aspects remain, body size and coloration influenced heat exchange, suggesting complex thermoregulatory strategies in these lizards, probably regulated through physiology and behavior, which may allow these small lizards to inhabit harsh weather environments. PMID:26896550

  9. Oxygen isotope mass balance of atmospheric nitrate at Dome C, East Antarctica, during the OPALE campaign

    Science.gov (United States)

    Savarino, Joël; Vicars, William C.; Legrand, Michel; Preunkert, Suzanne; Jourdain, Bruno; Frey, Markus M.; Kukui, Alexandre; Caillon, Nicolas; Gil Roca, Jaime

    2016-03-01

    Variations in the stable oxygen isotope composition of atmospheric nitrate act as novel tools for studying oxidative processes taking place in the troposphere. They provide both qualitative and quantitative constraints on the pathways determining the fate of atmospheric nitrogen oxides (NO + NO2 = NOx). The unique and distinctive 17O excess (Δ17O = δ17O - 0.52 × δ18O) of ozone, which is transferred to NOx via oxidation, is a particularly useful isotopic fingerprint in studies of NOx transformations. Constraining the propagation of 17O excess within the NOx cycle is critical in polar areas, where there exists the possibility of extending atmospheric investigations to the glacial-interglacial timescale using deep ice core records of nitrate. Here we present measurements of the comprehensive isotopic composition of atmospheric nitrate collected at Dome C (East Antarctic Plateau) during the austral summer of 2011/2012. Nitrate isotope analysis has been here combined for the first time with key precursors involved in nitrate production (NOx, O3, OH, HO2, RO2, etc.) and direct observations of the transferrable Δ17O of surface ozone, which was measured at Dome C throughout 2012 using our recently developed analytical approach. Assuming that nitrate is mainly produced in Antarctica in summer through the OH + NO2 pathway and using concurrent measurements of OH and NO2, we calculated a Δ17O signature for nitrate on the order of (21-22 ± 3) ‰. These values are lower than the measured values that ranged between 27 and 31 ‰. This discrepancy between expected and observed Δ17O(NO3-) values suggests the existence of an unknown process that contributes significantly to the atmospheric nitrate budget over this East Antarctic region. However, systematic errors or false isotopic balance transfer functions are not totally excluded.

  10. Effect of body mass and melanism on heat balance in Liolaemus lizards of the goetschi clade.

    Science.gov (United States)

    Moreno Azócar, Débora Lina; Bonino, Marcelo Fabián; Perotti, María Gabriela; Schulte, James A; Abdala, Cristian Simón; Cruz, Félix Benjamín

    2016-04-15

    The body temperature of ectotherms depends on the environmental temperatures and behavioral adjustments, but morphology may also have an effect. For example, in colder environments, animals tend to be larger and to show higher thermal inertia, as proposed by Bergmann's rule and the heat balance hypothesis (HBH). Additionally, dark coloration increases solar radiation absorption and should accelerate heat gain (thermal melanism hypothesis, TMH). We tested Bergmann's rule, the HBH and the TMH within the ITALIC! Liolaemus goetschilizard clade, which shows variability in body size and melanic coloration. We measured heating and cooling rates of live and euthanized animals, and tested how morphology and color affect these rates. Live organisms show less variable and faster heating rates compared with cooling rates, suggesting behavioral and/or physiological adjustments. Our results support Bergmann's rule and the HBH, as larger species show slower heating and cooling rates. However, we did not find a clear pattern to support the TMH. The influence of dorsal melanism on heating by radiation was masked by the body size effect in live animals, and results from euthanized individuals also showed no clear effects of melanism on heating rates. Comparison among three groups of live individuals with different degrees of melanism did not clarify the influence of melanism on heating rates. However, when euthanized animals from the same three groups were compared, we observed that darker euthanized animals actually heat faster than lighter ones, favoring the TMH. Although unresolved aspects remain, body size and coloration influenced heat exchange, suggesting complex thermoregulatory strategies in these lizards, probably regulated through physiology and behavior, which may allow these small lizards to inhabit harsh weather environments.

  11. Uncertainty of solute flux estimation in ungauged small streams: potential implications for input-output nutrient mass balances at stream reach scale

    Directory of Open Access Journals (Sweden)

    A. Butturini

    2005-01-01

    Full Text Available Input-output mass balances within stream reaches provide in situ estimates of stream nutrient retention/release under a wide spectrum of hydrological conditions. Providing good estimates of the mass balances for nutrients depends on precise hydrological monitoring and good chemical characterisation of stream water at the input and output ends of the stream reach. There is a need to optimise the hydrological monitoring and the frequencies of water sampling to yield precise annual mass balances, so as to avoid undue cost - high resolution monitoring and subsequent chemical analysis can be labour intensive and costly. In this paper, simulation exercises were performed using a data set created to represent the instantaneous discharge and solute dynamics at the input and output ends of a model stream reach during a one year period. At the output end, stream discharge and water chemistry were monitored continuously, while the input end was assumed to be ungauged; water sampling frequency was changed arbitrarily. Instantaneous discharge at the ungauged sampling point was estimated with an empirical power model linking the discharge to the catchment area (Hooper, 1986. The model thus substitutes for the additional gauge station. Simulations showed that 10 days was the longest chemical sampling interval which could provide reach annual mass balances of acceptable precision. Presently, the relationship between discharge and catchment area is usually assumed to be linear but simulations indicate that small departures from the linearity of this relationship could cause dramatic changes in the mass balance estimations.

  12. Simulation of rock mass balance of two typical altered rocks in Wulong gold deposit of Liaoning, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Wulong gold deposit hosted in granite and fine-grained diorite dikes, is a typical gold deposit of quartz vein type. Granite and fine-grained diorite dikes in the ore deposit were altered by metallogenic fluid.Based on the altered zoning, the samples of petrochemistry were collected and major and trace elements were analyzed systematically. Calculation of rock mass balance shows that the major elements (SiO2, K2 O, P2O5,Fe2 O3) in the two typical altered rocks are clearly added into the altered system, and that trace elements (V,Y, Zr, Ni, Co, Sr) assume an increasing and decreasing tendencies in the altered granite and altered diorite dike, respectively. The fluid/rock ratios are 30.17-181.00 and 115.44-692.67 respectively for altered granite and altered diorite dike, they have profoundly effects on metallogenesis.

  13. Brief Communication: Upper-air relaxation in RACMO2 significantly improves modelled interannual surface mass balance variability in Antarctica

    Science.gov (United States)

    van de Berg, Willem Jan; Medley, Brooke

    2016-03-01

    The Regional Atmospheric Climate Model (RACMO2) has been a powerful tool for improving surface mass balance (SMB) estimates from GCMs or reanalyses. However, new yearly SMB observations for West Antarctica show that the modelled interannual variability in SMB is poorly simulated by RACMO2, in contrast to ERA-Interim, which resolves this variability well. In an attempt to remedy RACMO2 performance, we included additional upper-air relaxation (UAR) in RACMO2. With UAR, the correlation to observations is similar for RACMO2 and ERA-Interim. The spatial SMB patterns and ice-sheet-integrated SMB modelled using UAR remain very similar to the estimates of RACMO2 without UAR. We only observe an upstream smoothing of precipitation in regions with very steep topography like the Antarctic Peninsula. We conclude that UAR is a useful improvement for regional climate model simulations, although results in regions with steep topography should be treated with care.

  14. Moisture and drug solid-state monitoring during a continuous drying process using empirical and mass balance models

    DEFF Research Database (Denmark)

    Fonteyne, Margot; Gildemyn, Delphine; Peeters, Elisabeth;

    2014-01-01

    Classically, the end point detection during fluid bed drying has been performed using indirect parameters, such as the product temperature or the humidity of the outlet drying air. This paper aims at comparing those classic methods to both in-line moisture and solid-state determination by means...... of Process Analytical Technology (PAT) tools (Raman and NIR spectroscopy) and a mass balance approach. The six-segmented fluid bed drying system being part of a fully continuous from-powder-to-tablet production line (ConsiGma™-25) was used for this study. A theophylline:lactose:PVP (30:67.5:2.5) blend...... was chosen as model formulation. For the development of the NIR-based moisture determination model, 15 calibration experiments in the fluid bed dryer were performed. Six test experiments were conducted afterwards, and the product was monitored in-line with NIR and Raman spectroscopy during drying...

  15. Mass-energy balance analysis for estimation of light energy conversion in an integrated system of biological H2 production

    Directory of Open Access Journals (Sweden)

    A.I. Gavrisheva

    2015-12-01

    Full Text Available The present study investigated an integrated system of biological H2 production, which includes the accumulation of biomass of autotrophic microalgae, dark fermentation of biomass, and photofermentation of the dark fermentation effluent. Particular emphasis was placed on the estimation of the conversion efficiency of light into hydrogen energy at each stage of this system. For this purpose, the mass and energy balance regularities were applied. The efficiency of the energy transformation from light into the microalgal biomass did not exceed 5%. The efficiency of the energy transformation from biomass to biological H2 during the dark fermentation stage stood at about 0.3%. The photofermentation stage using the model fermentation effluent could improve this estimation to 11%, resulting in an overall efficiency 0.55%. Evidently, this scheme is counterproductive for light energy bioconversion due to numerous intermediate steps even if the best published data would be taken into account.

  16. Increasing meltwater discharge from the Nuuk region of the Greenland ice sheet and implications for mass balance (1960-2012)

    DEFF Research Database (Denmark)

    van As, Dirk; Langer Andersen, Morten; Petersen, Dorthe;

    2014-01-01

    We assess the runoff and surface mass balance (SMB) of the Greenland ice sheet in the Nuuk region (southwest) using output of two regional climate models (RCMs) evaluated by observations. The region encompasses six glaciers that drain into Godthåbsfjord. RCM data (1960-2012) are resampled to a high...... of the marine-terminating glaciers, the region lost 10-20km3w.e. a-1 in 2010-12. If 2010 melting prevails during the remainder of this century, a low-end estimate of sea-level rise of 5mm is expected by 2100 from this relatively small section (2.6%) of the ice sheet alone....

  17. Atmospheric bromine flux from the coastal Abu Dhabi sabkhat: A ground-water mass-balance investigation

    Science.gov (United States)

    Wood, W.W.; Sanford, W.E.

    2007-01-01

    A solute mass-balance study of ground water of the 3000 km2 coastal sabkhat (salt flats) of the Emirate of Abu Dhabi, United Arab Emirates, documents an annual bromide loss of approximately 255 metric tons (0.0032 Gmoles), or 85 kg/km2. This value is an order of magnitude greater than previously published direct measurements from the atmosphere over an evaporative environment of a salar in Bolivia. Laboratory evidence, consistent with published reports, suggests that this loss is by vapor transport to the atmosphere. If this bromine flux to the atmosphere is representative of the total earth area of active salt flats then it is a significant, and generally under recognized, input to the global atmospheric bromide flux.

  18. Theory of the generalized chloride mass balance method for recharge estimation in groundwater basins characterised by point and diffuse recharge

    Directory of Open Access Journals (Sweden)

    N. Somaratne

    2014-01-01

    Full Text Available Application of the conventional chloride mass balance (CMB method to point recharge dominant groundwater basins can substantially under-estimate long-term average annual recharge by not accounting for the effects of localized surface water inputs. This is because the conventional CMB method ignores the duality of infiltration and recharge found in karstic systems, where point recharge can be a contributing factor. When point recharge is present in groundwater basins, recharge estimation is unsuccessful using the conventional CMB method with, either unsaturated zone chloride or groundwater chloride. In this paper we describe a generalized CMB that can be applied to groundwater basins with point recharge. Results from this generalized CMB are shown to be comparable with long-term recharge estimates obtained using the watertable fluctuation method, groundwater flow modelling and Darcy flow calculations. The generalized CMB method provides an alternative, reliable long-term recharge estimation method for groundwater basins characterised by both point and diffuse recharge.

  19. Mass and heat flux balance of La Soufrière volcano (Guadeloupe) from aerial infrared thermal imaging

    Science.gov (United States)

    Gaudin, Damien; Beauducel, François; Coutant, Olivier; Delacourt, Christophe; Richon, Patrick; de Chabalier, Jean-Bernard; Hammouya, Gilbert

    2016-06-01

    La Soufrière of Guadeloupe is an active volcano of Lesser Antilles that is closely monitored due to a high eruptive hazard potential. Since 1992 it exhibits a medium-level but sustained background hydrothermal activity with low-energy and shallow seismicity, hot springs temperature increase and high flux acidic gas fumaroles at the summit. The problem of estimating the heat balance and quantifying the evolution of hydrothermal activity has become a key challenge for surveillance. This work is the first attempt of a global mapping and quantification of La Soufrière thermal activity performed in February 2010 using aerial thermal infrared imagery. After instrument calibration and data processing, we present a global map of thermal anomalies allowing to spot the main active sites: the summit area (including the fumaroles of Tarissan Pit and South Crater), the Ty Fault fumarolic zone, and the hot springs located at the vicinity of the dome. In a second step, we deduce the mass and the energy fluxes released by the volcano. In particular, we propose a simple model of energy balance to estimate the mass flux of the summit fumaroles from their brightness temperature and size. In February 2010, Tarissan Pit had a 22.8 ± 8.1 kg s -1 flux (1970 ± 704 tons day -1), while South Crater vents had a total of 19.5 ± 4.0 kg s -1 (1687 ± 348 tons day -1). Once converted into energy flux, summit fumaroles represent 98% of the 106 ± 30 MW released by the volcano, the 2% remaining being split between the hot springs and the thermal anomalies at the summit and at the Ty Fault fumarolic zone. These values are in the high range of the previous estimations, highlighting the short-term variability of the expelled fluxes. Such a heat flux requires the cooling of 1500 m 3 of magma per day, in good agreement with previous geochemical studies.

  20. Methane mass balance at three landfill sites: What is the efficiency of capture by gas collection systems?

    International Nuclear Information System (INIS)

    Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill volume. This paper presents the results of extensive field campaigns at three landfill sites to elucidate the total methane balance and provide field measurements to quantify these pathways. We assessed the overall methane mass balance in field cells with a variety of designs, cover materials, and gas management strategies. Sites included different cell configurations, including temporary clay cover, final clay cover, geosynthetic clay liners, and geomembrane composite covers, and cells with and without gas collection systems. Methane emission rates ranged from -2.2 to >10,000 mg CH4 m-2 d-1. Total methane oxidation rates ranged from 4% to 50% of the methane flux through the cover at sites with positive emissions. Oxidation of atmospheric methane was occurring in vegetated soils above a geomembrane. The results of these studies were used as the basis for guidelines by the French environment agency (ADEME) for default values for percent recovery: 35% for an operating cell with an active landfill gas (LFG) recovery system, 65% for a temporary covered cell with an active LFG recovery system, 85% for a cell with clay final cover and active LFG recovery, and 90% for a cell with a geomembrane final cover and active LFG recovery

  1. Mass balance and isotope effects during nitrogen transport through septic tank systems with packed-bed (sand) filters

    Science.gov (United States)

    Hinkle, S.R.; Böhlke, J.K.; Fisher, L.H.

    2008-01-01

    Septic tank systems are an important source of NO3- to many aquifers, yet characterization of N mass balance and isotope systematics following septic tank effluent discharge into unsaturated sediments has received limited attention. In this study, samples of septic tank effluent before and after transport through single-pass packed-bed filters (sand filters) were evaluated to elucidate mass balance and isotope effects associated with septic tank effluent discharge to unsaturated sediments. Chemical and isotopic data from five newly installed pairs and ten established pairs of septic tanks and packed-bed filters serving single homes in Oregon indicate that aqueous solute concentrations are affected by variations in recharge (precipitation, evapotranspiration), NH4+ sorption (primarily in immature systems), nitrification, and gaseous N loss via NH3 volatilization and(or) N2 or N2O release during nitrification/denitrification. Substantial NH4+ sorption capacity was also observed in laboratory columns with synthetic effluent. Septic tank effluent ??15N-NH4+ values were almost constant and averaged + 4.9??? ?? 0.4??? (1 ??). In contrast, ??15N values of NO3- leaving mature packed-bed filters were variable (+ 0.8 to + 14.4???) and averaged + 7.2??? ?? 2.6???. Net N loss in the two networks of packed-bed filters was indicated by average 10-30% decreases in Cl--normalized N concentrations and 2-3??? increases in ??15N, consistent with fractionation accompanying gaseous N losses and corroborating established links between septic tank effluent and NO3- in a local, shallow aquifer. Values of ??18O-NO3- leaving mature packed-bed filters ranged from - 10.2 to - 2.3??? (mean - 6.4??? ?? 1.8???), and were intermediate between a 2/3 H2O-O + 1/3 O2-O conceptualization and a 100% H2O-O conceptualization of ??18O-NO3- generation during nitrification.

  2. Nitrogen attenuation in the Connecticut River, northeastern USA; a comparison of mass balance and N2 production modeling approaches

    Science.gov (United States)

    Smith, T.E.; Laursen, A.E.; Deacon, J.R.

    2008-01-01

    Two methods were used to measure in-stream nitrogen loss in the Connecticut River during studies conducted in April and August 2005. A mass balance on nitrogen inputs and output for two study reaches (55 and 66 km), at spring high flow and at summer low flow, was computed on the basis of total nitrogen concentrations and measured river discharges in the Connecticut River and its tributaries. In a 10.3 km subreach of the northern 66 km reach, concentrations of dissolved N2 were also measured during summer low flow and compared to modeled N2 concentrations (based on temperature and atmospheric gas exchange rates) to determine the measured "excess" N2 that indicates denitrification. Mass balance results showed no in-stream nitrogen loss in either reach during April 2005, and no nitrogen loss in the southern 55 km study reach during August 2005. In the northern 66 km reach during August 2005, however, nitrogen output was 18% less than the total nitrogen inputs to the reach. N2 sampling results gave an estimated rate of N2 production that would remove 3.3% of the nitrogen load in the river over the 10.3 km northern sub-reach. The nitrogen losses measured in the northern reach in August 2005 may represent an approximate upper limit for nitrogen attenuation in the Connecticut River because denitrification processes are most active during warm summer temperatures and because the study was performed during the annual low-flow period when total nitrogen loads are small. ?? 2008 Springer Science+Business Media B.V.

  3. Contents and mass balances of cadmium and arsenic in a wastewater-fed fish pond of Hoang Mai, Hanoi, Vietnam.

    Science.gov (United States)

    Marcussen, Helle; Ha, Le Thai; Polprasert, Chongrak; Holm, Peter E

    2012-01-01

    Wastewater-fed aquatic production has been practiced since the 1960s in peri-urban Hanoi. Wastewater is used as a cheap and reliable source of both water and nutrients but there is a risk that it may lead to accumulation of potentially toxic elements (PTEs) in the production systems and produce and thereby constitute a food safety risk. This study investigates the cadmium (Cd) and arsenic (As) concentrations in water, sediment, plant and fish of a wastewater fed-fish pond in Hoang Mai district, Hanoi, Vietnam. Cd concentrations in the water were lower than the Vietnamese quality guidelines (0.8-1.8 μg Cd/L) for protection of aquatic life but As concentrations in inlet and outlet water of 44.3 and 21.3 μg/L, respectively both were higher that the guidelines (20 μg As/L) and may cause toxicity to fish in the pond and the surrounding vegetable farms using the outlet water for irrigation. The concentrations of Cd and As in fish and Cd in water spinach did not constitute a food safety risk. However, As concentrations in water spinach may be of concern. A mass balance estimate for the fish pond showed that about 12% of the incoming As accumulate in suspended particular matters, 40% settle down to the sediment, less than 0.1% accumulate in the fish and water spinach and 48% overflow with the pond effluent. The concentrations of Cd were too low to make a mass balance for the fish pond. PMID:22934996

  4. Three-Dimensional Structure and Energy Balance of a Coronal Mass Ejection

    Science.gov (United States)

    Lee, J.-Y.; Raymond, J. C.; Ko, Y.-K.; Kim, K.-S.

    2009-01-01

    UVCS observed Doppler-shifted material of a partial halo coronal mass ejection (CME) on 2001 December 13. The observed ratio of [O VJ/O V] is a reliable density diagnostic important for assessing the state of the plasma. Earlier UVCS observations of CMEs found evidence that the ejected plasma is heated long after the eruption. This paper investigated the heating rates, which represent a significant fraction of the CME energy budget. The parameterized heating and radiative and adiabatic cooling have been used to evaluate the temperature evolution of the CME material with a time-dependent ionization state model. Continuous heating is required to match the UVCS observations. To match the O VI bright knots, a higher heating rate is required such that the heating energy is greater than the kinetic energy.

  5. Processes governing the mass balance of Chhota Shigri Glacier (western Himalaya, India) assessed by point-scale surface energy balance measurements

    OpenAIRE

    Azam, M. F.; P. Wagnon; Vincent, C; Ramanathan, Al.; Favier, V.; Mandal, A; Pottakkal, J. G.

    2014-01-01

    Some recent studies revealed that Himalayan glaciers were shrinking at an accelerated rate since the beginning of the 21st century. However, the climatic causes for this shrinkage remain unclear given that surface energy balance studies are almost nonexistent in this region. In this study, a point-scale surface energy balance analysis was performed using in situ meteorological data from the ablation zone of Chhota Shigri Glacier over two separate periods (August 2012 to February 2013 and July...

  6. Processes governing the mass balance of Chhota Shigri Glacier (Western Himalaya, India) assessed by point-scale surface energy balance measurements

    OpenAIRE

    Azam, M. F.; P. Wagnon; Vincent, C; AL. Ramanathan; Mandal, A; Pottakkal, J. G.

    2014-01-01

    Recent studies revealed that Himalayan glaciers have been shrinking at an accelerated rate since the beginning of the 21st century. However the climatic causes for this shrinkage remain unclear given that surface energy balance studies are almost nonexistent in this region. In this study, a point-scale surface energy balance analysis was performed using in-situ meteorological data from the ablation zone of Chhota Shigri Glacier over two separate periods (Aug...

  7. Mass balance and life cycle assessment of the waste electrical and electronic equipment management system implemented in Lombardia Region (Italy)

    International Nuclear Information System (INIS)

    Waste electrical and electronic equipment (WEEE) is one of the fastest growing waste streams in Europe, whose content of hazardous substances as well as of valuable materials makes the study of the different management options particularly interesting. The present study investigates the WEEE management system in Lombardia Region (Italy) in the year 2011 by applying the life cycle assessment (LCA) methodology. An extensive collection of primary data was carried out to describe the main outputs and the energy consumptions of the treatment plants. Afterwards, the benefits and burdens associated with the treatment and recovery of each of the five categories in which WEEE is classified according to the Italian legislation (heaters and refrigerators — R1, large household appliances — R2, TV and monitors — R3, small household appliances — R4 and lighting equipment — R5) were evaluated. The mass balance of the treatment and recovery system of each of the five WEEE categories showed that steel and glass are the predominant streams of materials arising from the treatment; a non-negligible amount of plastic is also recovered, together with small amounts of precious metals. The LCA of the regional WEEE management system showed that the benefits associated with materials and energy recovery balance the burdens of the treatment processes, with the sole exception of two impact categories (human toxicity-cancer effects and freshwater ecotoxicity). The WEEE categories whose treatment and recovery resulted more beneficial for the environment and the human health are R3 and R5. The contribution analysis showed that overall the main benefits are associated with the recovery of metals, as well as of plastic and glass. Some suggestions for improving the performance of the system are given, as well as an indication for a more-in-depth analysis for the toxicity categories and a proposal for a new characterisation method for WEEE. - Highlights: • The WEEE management system in

  8. Mass balance and life cycle assessment of the waste electrical and electronic equipment management system implemented in Lombardia Region (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Biganzoli, L., E-mail: laura.biganzoli@mail.polimi.it; Falbo, A.; Forte, F.; Grosso, M.; Rigamonti, L.

    2015-08-15

    Waste electrical and electronic equipment (WEEE) is one of the fastest growing waste streams in Europe, whose content of hazardous substances as well as of valuable materials makes the study of the different management options particularly interesting. The present study investigates the WEEE management system in Lombardia Region (Italy) in the year 2011 by applying the life cycle assessment (LCA) methodology. An extensive collection of primary data was carried out to describe the main outputs and the energy consumptions of the treatment plants. Afterwards, the benefits and burdens associated with the treatment and recovery of each of the five categories in which WEEE is classified according to the Italian legislation (heaters and refrigerators — R1, large household appliances — R2, TV and monitors — R3, small household appliances — R4 and lighting equipment — R5) were evaluated. The mass balance of the treatment and recovery system of each of the five WEEE categories showed that steel and glass are the predominant streams of materials arising from the treatment; a non-negligible amount of plastic is also recovered, together with small amounts of precious metals. The LCA of the regional WEEE management system showed that the benefits associated with materials and energy recovery balance the burdens of the treatment processes, with the sole exception of two impact categories (human toxicity-cancer effects and freshwater ecotoxicity). The WEEE categories whose treatment and recovery resulted more beneficial for the environment and the human health are R3 and R5. The contribution analysis showed that overall the main benefits are associated with the recovery of metals, as well as of plastic and glass. Some suggestions for improving the performance of the system are given, as well as an indication for a more-in-depth analysis for the toxicity categories and a proposal for a new characterisation method for WEEE. - Highlights: • The WEEE management system in

  9. Performance of human mass balance studies with stable isotope-labeled drug and continuous flow-isotope ratio mass spectrometry: a progress report.

    Science.gov (United States)

    Browne, T R; Szabo, G K; Ajami, A; Browne, D G

    1998-04-01

    We propose performing human mass balance studies by administering stable isotope labeled (13C or 15N) drug and quantitating excess (above background) 13C or 15N in urine, serum, and feces by continuous flow-isotope ratio mass spectrometry (CF-IRMS). Theoretical calculations and empirical data (dynamic range, linearity, sensitivity, precision, accuracy) are presented to establish that commercially available CF-IRMS instruments can quantitate stable isotope labeled (one or two 15N or 13C labels) drug concentrations of 1.0 microg/mL or greater in urine, serum (15N), or feces. More than two 13C labels may be necessary to quantitate 1.0 microg/mL of drug in serum. Three volunteers received 650 mg of 15N13C2-acetaminophen, and urine was collected for 72 hours. Percent of administered label recovered in urine from the three subjects was 97.4, 78.9, and 95.4 for 13C and 90.3, 77.0, and 90.6 for 15N. Fecal recovery of label for one subject was 0.9% (13C2) and 1.1% (15N). Serum pharmacokinetic values obtained by counting 13C or 15N in one subject were as expected for acetaminophen. This method appears to be promising, and further validation is ongoing. PMID:9590457

  10. Evolution of Popocatépetl volcano's glaciers in Mexico with and without volcanic activity: diagnosis from a minimal mass balance model

    Science.gov (United States)

    Ontiveros-Gonzalez, G.; Cortes Ramos, J.; Delgado Granados, H.

    2013-05-01

    This work describes the influence of eruptive activity on the evolution of the glacial cover on Popocatepetl volcano. Here, we try to answer a simple question: what had happened if this glacier had not been affected by the volcanic activity? In order to answer this question we modeled the mass balance evolution of this glacier using meteorological data and a minimal mass balance model developed for glaciers elsewhere. For this model we assumed no volcanic activity. These results were compared with measurements available for the actual situation at Popocatépetl Volcano. It was possible to separate the influence of the volcanic activity on the evolution of this glacier system considering two scenarios: one was modeled with a simulation of the mass balance where volcanic activity does not affect, and a second scenario is based on the documented studies developed around the glacial disappearance of the glaciers.

  11. Carbon and Isotopic Mass Balance Models of Oasis Valley-Fortymile Canyon Groundwater Basin, Southern Nevada

    Science.gov (United States)

    White, Art F.; Chuma, Nancy J.

    1987-04-01

    Environmental isotopes and carbon chemistry provide means of differentiating various recharge areas, flow paths, and ages of groundwater in portions of the Nevada Test Site and vicinity. Regional δD/δ18O trends are offset from the present-day meteoric line by a deuterium depletion of 5‰, suggesting paleoclimatic changes. Partial pressures of CO2 and the 18O and 13C data indicate solubility and isotopic equilibrium between the gas and water in the soil zone with progressive exchange with underlying groundwater in the shallow alluvium of Oasis Valley. Application of a closed system CO2 model using the EQ3NR/EQ6 reaction path simulator successfully reproduces chemical compositions observed in the alluvium in the Amargosa Desert and in the deep tuff aquifer beneath Pahute Mesa and Yucca Mountain. Initial PCO2 input to the soil zone during recharge was calculated to range from 0.03 to 0.10 atm, which is comparable to measured soil CO2 pressures in Oasis Valley. Results are compared for 14C ages using the δ13C dilution correction and a mass action correction term relating predicted and calculated ionic activity products of CaCO3. Results are generally comparable with discrepancies attributed to anomalous δ13C values.

  12. Textile protection of snow and ice: Measured and simulated effects on the energy- and mass balance

    Science.gov (United States)

    Olefs, Marc; Lehning, Michael

    2010-05-01

    Measurements and simulations of the energy fluxes and mass changes of an artificially covered snow and ice surface (geotextile material) and a reference plot within an Austrian glacier ski resort are presented and compared. A modified version of the snow cover model SNOWPACK is used to successfully reproduce the artificially compacted and the additionally covered snow cover in a physically based way. Supplementary measurements of crucial material properties of the 0.0045 m thin geotextile serve as model input as well. Results indicate that the shortwave reflectivity of the covers is responsible for half the performance (47%). Thermal insulation of the material (14%) and a negative latent heat flux due to evaporation of precipitation from the cover surface (10%) have almost the same contribution. An assumed layer of air between the cover and the snow and ice surface (thickness 0.075 m to 0.12 m) adds the rest, which is at the upper limit of observations and may therefore also compensate for model errors. This generally explains the high performance of the method in glacier skiing resorts and, most importantly, an altitude dependant application limit of the method: the method becomes less effective at lower altitudes, where sensible heat fluxes become more important compared to short wave radiation.

  13. Mass Balance Changes and Ice Dynamics of Greenland and Antarctic Ice Sheets from Laser Altimetry

    Science.gov (United States)

    Babonis, G. S.; Csatho, B.; Schenk, T.

    2016-06-01

    During the past few decades the Greenland and Antarctic ice sheets have lost ice at accelerating rates, caused by increasing surface temperature. The melting of the two big ice sheets has a big impact on global sea level rise. If the ice sheets would melt down entirely, the sea level would rise more than 60 m. Even a much smaller rise would cause dramatic damage along coastal regions. In this paper we report about a major upgrade of surface elevation changes derived from laser altimetry data, acquired by NASA's Ice, Cloud and land Elevation Satellite mission (ICESat) and airborne laser campaigns, such as Airborne Topographic Mapper (ATM) and Land, Vegetation and Ice Sensor (LVIS). For detecting changes in ice sheet elevations we have developed the Surface Elevation Reconstruction And Change detection (SERAC) method. It computes elevation changes of small surface patches by keeping the surface shape constant and considering the absolute values as surface elevations. We report about important upgrades of earlier results, for example the inclusion of local ice caps and the temporal extension from 1993 to 2014 for the Greenland Ice Sheet and for a comprehensive reconstruction of ice thickness and mass changes for the Antarctic Ice Sheets.

  14. Does infection tilt the scales? Disease effects on the mass balance of an invertebrate nutrient recycler.

    Science.gov (United States)

    Narr, Charlotte F; Frost, Paul C

    2015-12-01

    While parasites are increasingly recognized as important components of ecosystems, we currently know little about how they alter ecosystem nutrient availability via host-mediated nutrient cycling. We examined whether infection alters the flow of nutrients through hosts and whether such effects depend upon host diet quality. To do so, we compared the mass specific nutrient (i.e., nitrogen and phosphorus) release rates, ingestion rates, and elemental composition of uninfected Daphnia to those infected with a bacterial parasite, P. ramosa. N and P release rates were increased by infection when Daphnia were fed P-poor diets, but we found no effect of infection on the nutrient release of individuals fed P-rich diets. Calculations based on the first law of thermodynamics indicated that infection should increase the nutrient release rates of Daphnia by decreasing nutrient accumulation rates in host tissues. Although we found reduced nutrient accumulation rates in infected Daphnia fed all diets, this reduction did not increase the nutrient release rates of Daphnia fed the P-rich diet because infected Daphnia fed this diet ingested nutrients more slowly than uninfected hosts. Our results thus indicate that parasites can significantly alter the nutrient use of animal consumers, which could affect the availability of nutrients in heavily parasitized environments. PMID:26298190

  15. Mass balance, meteorology, area altitude distribution, glacier-surface altitude, ice motion, terminus position, and runoff at Gulkana Glacier, Alaska, 1996 balance year

    Science.gov (United States)

    March, Rod S.

    2003-01-01

    The 1996 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier Basin were evaluated on the basis of meteorological, hydrological, and glaciological data. Averaged over the glacier, the measured winter snow balance was 0.87 meter on April 18, 1996, 1.1 standard deviation below the long-term average; the maximum winter snow balance, 1.06 meters, was reached on May 28, 1996; and the net balance (from August 30, 1995, to August 24, 1996) was -0.53 meter, 0.53 standard deviation below the long-term average. The annual balance (October 1, 1995, to September 30, 1996) was -0.37 meter. Area-averaged balances were reported using both the 1967 and 1993 area altitude distributions (the numbers previously given in this abstract use the 1993 area altitude distribution). Net balance was about 25 percent less negative using the 1993 area altitude distribution than the 1967 distribution. Annual average air temperature was 0.9 degree Celsius warmer than that recorded with the analog sensor used since 1966. Total precipitation catch for the year was 0.78 meter, 0.8 standard deviations below normal. The annual average wind speed was 3.5 meters per second in the first year of measuring wind speed. Annual runoff averaged 1.50 meters over the basin, 1.0 standard deviation below the long-term average. Glacier-surface altitude and ice-motion changes measured at three index sites document seasonal ice-speed and glacier-thickness changes. Both showed a continuation of a slowing and thinning trend present in the 1990s. The glacier terminus and lower ablation area were defined for 1996 with a handheld Global Positioning System survey of 126 locations spread out over about 4 kilometers on the lower glacier margin. From 1949 to 1996, the terminus retreated about 1,650 meters for an average retreat rate of 35 meters per year.

  16. Modelling the geometry of a moving laser melt pool and deposition track via energy and mass balances

    International Nuclear Information System (INIS)

    The additive manufacturing technique of laser direct metal deposition allows multiple tracks of full density metallic material to be built to form complex parts for rapid tooling and manufacture. Practical results and theoretical models have shown that the geometries of the tracks are governed by multiple factors. Original work with single layer cladding identified three basic clad profiles but, so far, models of multiple layer, powder-feed deposition have been based on only two of them. At higher powder mass flow rates, experimental results have shown that a layer's width can become greater than the melt pool width at the substrate surface, but previous analytical models have not been able to accommodate this. In this paper, a model based on this third profile is established and experimentally verified. The model concentrates on mathematical analysis of the melt pool and establishes mass and energy balances based on one-dimensional heat conduction to the substrate. Deposition track limits are considered as arcs of circles rather than of ellipses, as used in most established models, reflecting the dominance of surface tension forces in the melt pool, and expressions for elongation of the melt pool with increasing traverse speed are incorporated. Trends in layer width and height with major process parameters are captured and predicted layer dimensions correspond well to the experimental values

  17. Extent of Low-accumulation 'Wind Glaze' Areas on the East Antarctic Plateau: Implications for Continental Ice Mass Balance

    Science.gov (United States)

    Scambos, Theodore A.; Frezzotti, Massimo; Haran, T.; Bohlander, J.; Lenaerts, J. T. M.; Van Den Broeke, M. R.; Jezek, K.; Long, D.; Urbini, S.; Farness, K.; Neumann, T.; Albert, M.; Winther, J.-G.

    2012-01-01

    Persistent katabatic winds form widely distributed localized areas of near-zero net surface accumulation on the East Antarctic ice sheet (EAIS) plateau. These areas have been called 'glaze' surfaces due to their polished appearance. They are typically 2-200 square kilometers in area and are found on leeward slopes of ice-sheet undulations and megadunes. Adjacent, leeward high-accumulation regions (isolated dunes) are generally smaller and do not compensate for the local low in surface mass balance (SMB). We use a combination of satellite remote sensing and field-gathered datasets to map the extent of wind glaze in the EAIS above 1500m elevation. Mapping criteria are derived from distinctive surface and subsurface characteristics of glaze areas resulting from many years of intense annual temperature cycling without significant burial. Our results show that 11.2 plus or minus 1.7%, or 950 plus or minus 143 x 10(exp 3) square kilometers, of the EAIS above 1500m is wind glaze. Studies of SMB interpolate values across glaze regions, leading to overestimates of net mass input. Using our derived wind-glaze extent, we estimate this excess in three recent models of Antarctic SMB at 46-82 Gt. The lowest-input model appears to best match the mean in regions of extensive wind glaze.

  18. 21st century projections of surface mass balance changes for major drainage systems of the Greenland ice sheet

    International Nuclear Information System (INIS)

    Outputs from the regional climate model Modèle Atmosphérique Régionale at a spatial resolution of 25 km are used to study 21st century projected surface mass balance (SMB) over six major drainage basins of the Greenland ice sheet (GrIS). The regional model is forced with the outputs of three different Earth System Models (CanESM2, NorESM1 and MIROC5) obtained when considering two greenhouse gas future scenarios with levels of CO2 equivalent of, respectively, 850 and >1370 ppm by 2100. Results indicate that the increase in runoff due to warming will exceed the increased precipitation deriving from the increase in evaporation for all basins, with the amount of net loss of mass at the surface varying spatially. Basins along the southwest and north coast are projected to have the highest sensitivity of SMB to increasing temperatures. For these basins, the global temperature anomaly corresponding to a decrease of the SMB below the 1980–99 average (when the ice sheet was near the equilibrium) ranges between +0.60 and +2.16 °C. For the basins along the northwest and northeast, these values range between +1.50 and +3.40 °C. Our results are conservative as they do not account for ice dynamics and changes in the ice sheet topography. (letter)

  19. Previously hidden low-energy ions: a better map of near-Earth space and the terrestrial mass balance

    Science.gov (United States)

    André, Mats

    2015-12-01

    This is a review of the mass balance of planet Earth, intended also for scientists not usually working with space physics or geophysics. The discussion includes both outflow of ions and neutrals from the ionosphere and upper atmosphere, and the inflow of meteoroids and larger objects. The focus is on ions with energies less than tens of eV originating from the ionosphere. Positive low-energy ions are complicated to detect onboard sunlit spacecraft at higher altitudes, which often become positively charged to several tens of volts. We have invented a technique to observe low-energy ions based on the detection of the wake behind a charged spacecraft in a supersonic ion flow. We find that low-energy ions usually dominate the ion density and the outward flux in large volumes in the magnetosphere. The global outflow is of the order of 1026 ions s-1. This is a significant fraction of the total number outflow of particles from Earth, and changes plasma processes in near-Earth space. We compare order of magnitude estimates of the mass outflow and inflow for planet Earth and find that they are similar, at around 1 kg s-1 (30 000 ton yr-1). We briefly discuss atmospheric and ionospheric outflow from other planets and the connection to evolution of extraterrestrial life.

  20. Garnet and clinopyroxene pseudomorphs: example of local mass balance in the Caledonides of western Norway.

    Science.gov (United States)

    Centrella, Stephen; Austrheim, Håkon; Putnis, Andrew

    2015-04-01

    The Precambrian granulite facies rocks of Lindås Nappe, Bergen Arcs, Caledonides of W.Norway are partially hydrated at amphibolites and eclogite facies conditions. The Lindås Nappe outcrop over an area of ca 1000 km2 where relict granulite facies lenses make up only ca 10%. At Hillandsvatnet, garnetite displays sharp hydration fronts across which the granulite facies assemblage composed of garnet (70%) and clinopyroxene (30%) is replaced by an amphibolite facies mineralogy defined by chlorite, epidote and amphibole. This setting allows us to assess the mechanism of fluid transport through an initially low permeability rock and how this induces changes of texture and element transport. The replacement of garnet and clinopyroxene is pseudomorphic so that the grain shapes of the garnet and clinopyroxene are preserved even if when they are completely replaced. This requires that the reactive fluids must pass through the solid crystal grains and this can be achieved by an interface coupled dissolution-precipitation mechanism. Porosity generation is a key feature of this mechanism (Putnis and Austrheim 2012). The porosity is not only a consequence of reduction in solid molar volume but depends on the relative solubilities of parent and product phases in the reactive fluid. Putnis et al. 2007 and Xia et al. 2009 have shown that even in pseudomorphic reactions where the molar volume increases, porosity may still be generated by the reaction. This is fundamental in understanding the element mobility and the mass transfer in a low permeability rock even more when the bulk rock composition of these two rocks stay unchanged; except a gain in water during amphibolitisation. The textural evolution during the replacement of garnet by pargasite, epidote and chlorite and pyroxene by hornblende and quartz in our rock sample conforms to that expected by a coupled dissolution-precipitation mechanism. SEM and Microprobe analysis coupled with the software XMapTools V 1.06.1 .(Lanari

  1. Operational System for Estimating Compaction of Arctic Glacial Firn and Surface Mass Balance

    Science.gov (United States)

    Crowell, J. M.; Behar, A.; Howat, I. M.; de la Peña, S.; Thanga, J.

    2015-12-01

    NASA and other agencies are invested in obtaining measurements of Greenland Ice Sheet surface elevation with the objective of constraining the ice sheet's contribution to present and future sea level rise. However, a major limitation of repeat altimetry measurements, such as air and space-based surveys, is that variations in the density of surface accumulation and the firn layer must be constrained in order to relate changes in ice thickness to the overall ice sheet mass imbalance. The temporal variability of accumulation thickness and firn compaction rate is poorly constrained, particularly in regions subject to surface melt and refreezing. Additionally, recent warming and extreme melt events may be substantially changing the density of the firn, affecting altimeter measurements. This knowledge gap about snow accumulation and firn density, therefore, is a critical challenge to the ICESat-2 mission objectives. Our in-situ sensor packages, dubbed the Compaction Reconnaissance of Arctic Glacial Snow (CRAGS), will aid the deconvolution of surface change observations, with the goal of providing an operational system in concert with the launch of ICESat-2. The CRAGS prototype was deployed in April 2014 at 69.0754N, -45.6603E, and two fully-equipped systems were deployed in April 2015 at 69.0952N, -46.4446E and 69.0527N, -44.4281E. CRAGS is a tower system equipped with three instruments for measuring snow accumulation: a strain sensor, a sonar, and a snow scale. These systems will be taking measurements for at least two more years, but they are designed to last longer with limited maintenance. The use of a modular tower design allows for them to be extended higher for many years of observations. This method will supplement air and space-based observations, providing the polar science community with valuable ground-truth data regarding the state of the interior of the Greenland ice sheet.

  2. The mass balance calculation of hydrothermal alteration in Sarcheshmeh porphyry copper deposit

    Directory of Open Access Journals (Sweden)

    Mohammad Maanijou

    2013-10-01

    Full Text Available Sarcheshmeh porphyry copper deposit is located 65 km southwest of Rafsanjan in Kerman province. The Sarcheshmeh deposit belongs to the southeastern part of Urumieh-Dokhtar magmatic assemblage (i.e., Dehaj-Sarduyeh zone. Intrusion of Sarcheshmeh granodiorite stock in faulted and thrusted early-Tertiary volcano-sedimentary deposits, led to mineralization in Miocene. In this research, the mass changes and element mobilities during hydrothermal process of potassic alteration were studied relative to fresh rock from the deeper parts of the plutonic body, phyllic relative to potassic, argillic relative to phyllic and propylitic alteration relative to fresh andesites surrounding the deposit. In the potassic zone, enrichment in Fe2O3 and K2O is so clear, because of increasing Fe coming from biotite alteration and presence of K-feldspar, respectively. Copper and molybdenum enrichments resulted from presence of chalcopyrite, bornite and molybdenite mineralization in this zone. Enrichment of SiO2 and depletion of CaO, MgO, Na2O and K2O in the phyllic zone resulted from leaching of sodium, calcium and magnesium from the aluminosilicate rocks and alteration of K-feldspar to sericite and quartz. In the argillic zone, Al2O3, CaO, MgO, Na2O and MnO have also been enriched in which increasing Al2O3 may be from kaolinite and illite formation. Also, enrichment in SiO2, Al2O3 and CaO in propylitic alteration zone can be attributed to the formation of chlorite, epidote and calcite as indicative minerals of this zone.

  3. Application and validation of long-range terrestrial laser scanning to monitor the mass balance of very small glaciers in the Swiss Alps

    Science.gov (United States)

    Fischer, Mauro; Huss, Matthias; Kummert, Mario; Hoelzle, Martin

    2016-06-01

    Due to the relative lack of empirical field data, the response of very small glaciers (here defined as being smaller than 0.5 km2) to current atmospheric warming is not fully understood yet. Investigating their mass balance, e.g. using the direct glaciological method, is a prerequisite to fill this knowledge gap. Terrestrial laser scanning (TLS) techniques operating in the near infrared range can be applied for the creation of repeated high-resolution digital elevation models and consecutive derivation of annual geodetic mass balances of very small glaciers. This method is promising, as laborious and potentially dangerous field measurements as well as the inter- and extrapolation of point measurements can be circumvented. However, it still needs to be validated. Here, we present TLS-derived annual surface elevation and geodetic mass changes for five very small glaciers in Switzerland (Glacier de Prapio, Glacier du Sex Rouge, St. Annafirn, Schwarzbachfirn, and Pizolgletscher) and two consecutive years (2013/14-2014/15). The scans were acquired with a long-range Riegl -6000 especially designed for surveying snow- and ice-covered terrain. Zonally variable conversion factors for firn and bare ice surfaces were applied to convert geodetic volume to mass changes. We compare the geodetic results to direct glaciological mass balance measurements coinciding with the TLS surveys and assess the uncertainties and errors included in both methods. Average glacier-wide mass balances were negative in both years, showing stronger mass losses in 2014/15 (-1.65 m w.e.) compared to 2013/14 (-0.59 m w.e.). Geodetic mass balances were slightly less negative but in close agreement with the direct glaciological ones (R2 = 0.91). Due to the dense in situ measurements, the uncertainties in the direct glaciological mass balances were small compared to the majority of measured glaciers worldwide (±0.09 m w.e. yr-1 on average), and similar to uncertainties in the TLS-derived geodetic mass

  4. Reconstruction of mass balance of Nevado Coropuna glaciers (Southern Peru) for Late Pleistocene, Little Ice Age and the present.

    Science.gov (United States)

    Ubeda, J.; Palacios, D.

    2009-04-01

    The Nevado Coropuna volcanic complex (15th 31'S-72 ° 39 ° W) is the quaternary stratovolcano northernmost of the central volcanic zone (CVZ) in the western flank of the Central Andes (Southern Peru). This consists in four adjacent volcanic buildings that are occupied over 5.100-5.700 masl by a system of glaciers covering an area of 47 Km2 in 2007 (Ubeda et al, 2008). The maximum expansion of glaciers during the Pleistocene affected an area of ~449 Km2, dropping to altitudes around 3.600-4800 m (Ubeda et al, 2007). In this work were mapped several hundreds of moraines which constitute a record of climate change since the last glacial maximum (LGM). Current glacier system is formed by dozen of glaciers descending slope down in all directions. Coropuna complex is an excellent laboratory for to investigate the control that climate change, tectonics and volcanism exert on the dynamics of glaciers, a scale of tens of years (by studying current glaciers) and also of tens of thousands of years (by analyzing the geomorphological evidence of its evolution in the past). Ubeda et al. (2008) analyzed the evolution of eighteen glaciers of Nevado Coropuna using indicators as surfaces and Equilibrium Line Altitudes (ELAs) of ice masses in 2007, 1986, 1955, Little the Ice Age (LIA) and Last Glacial Maximum (LGM). The glaciers were grouped into two sets: NE group (seven glaciers) and SE group (eleven glaciers). The work included statistical series of ELAs in each phase, estimates by Area x Altitud Balance Ratio (AABR) method, which was proposed by Osmaston (2005), in addition with estimates of timing (~17Cl36 Ka) and magnitude (~ 782-911 m) of ELA depression during LGM. The work included statistical series of ELAs in each phase, estimates by the method Area x Altitud Balance Ratio (AABR) proposed by Osmaston (2005), and in addition estimates of the timing (~17Cl36 Ka) and magnitude (~ 782-911 m) of ELA depression during LGM. The objective of this work is to estimate the current

  5. PGC-1α is important for maintaining the balance of muscle mass and myofiber types in unloaded muscle atrophy

    Science.gov (United States)

    Chen, Xiaoping; He, Jian; Wang, Fei; Zhang, Peng; Liu, Hongju; Li, Wenjiong

    2016-07-01

    PGC-1α, a transcriptional co-activator, has been shown mainly to determine the development of oxidative myofibers in skeletal muscle. However, whether PGC-1α functions to regulate the unloaded muscle atrophy and composition of myofiber types keeps unclear. MCK-PGC-1α overexpression transgenic mice (TG) and its wild type littermates (WT) were subjected to hindlimb unloading (HU) and induced unloaded muscle atrophy. After 14 days of HU, the mass of gastrocnemius, soleus, and plantaris muscles in WT mice decreased 17.9%, 28.2%, and 14.8%, respectively (Pmuscles. PGC-1α transgenic mice showed a 14.0% (Pmuscles mass after HU. To further confirm the effect of PGC-1α over-expression on the muscle mass loss under HU, change rate of muscle-body weight ratio was calculated, and the results indicated that the reduction of change rate of muscle-body weight ratio in PGC-1α transgenic gastrocnemius and soleus was significantly less than in WT mice (Pmuscle atrophy and myofiber switching from oxidative to glycolytic associated with a decrease in pSmad3 level after 14 days of HU. Importantly, overexpression of PGC-1α in C2C12 myoblasts protected PGC-1α-transfected myotubes from atrophy in vitro and the effect could be partially blocked by inducing pSmad3 with constitutively activated Smad3(C.A. smad3) transfection. Therefore, this study demonstrated a novel role and mechanism for PGC-1α in maintaining the balance of muscle mass and myofiber type MHCs in unloaded muscle atrophy via suppressing Smad3 activation. This report may prompt a hopeful therapeutic strategy for maintaining muscle mass and fiber type composition in disused muscle atrophies such as space weightlessness- or immobilization-induced muscle atrophy. Acknowledgments This work was supported by the Natural Sciences Foundation of China (31171144, 81272177 and 31171148), the State Key Laboratory Grant of Space Medicine Fundamentals and Application (SMFA13A01), and the National Key Laboratory Grant of Human

  6. Influence of secondary settling tank performance on suspended solids mass balance in activated sludge systems.

    Science.gov (United States)

    Patziger, M; Kainz, H; Hunze, M; Józsa, J

    2012-05-01

    Secondary settling is the final step of the activated sludge-based biological waste water treatment. Secondary settling tanks (SSTs) are therefore an essential unit of producing a clear effluent. A further important function of SSTs is the sufficient thickening to achieve highly concentrated return sludge and biomass within the biological reactor. In addition, the storage of activated sludge is also needed in case of peak flow events (Ekama et al., 1997). Due to the importance of a high SST performance the problem has long been investigated (Larsen, 1977; Krebs, 1991; Takács et al., 1991; Ekama et al., 1997; Freimann, 1999; Patziger et al., 2005; Bürger et al., 2011), however, a lot of questions are still to solve regarding e.g. the geometrical features (inflow, outflow) and operations (return sludge control, scraper mechanism, allowable maximum values of surface overflow rates). In our study we focused on SSTs under dynamic load considering both the overall unsteady behaviour and the features around the peaks, investigating the effect of various sludge return strategies as well as the inlet geometry on SST performance. The main research tool was a FLUENT-based novel mass transport model consisting of two modules, a 2D axisymmetric SST model and a mixed reactor model of the biological reactor (BR). The model was calibrated and verified against detailed measurements of flow and concentration patterns, sludge settling, accompanied with continuous on-line measurement of in- and outflow as well as returned flow rates of total suspended solids (TSS) and water. As to the inlet arrangement a reasonable modification of the geometry could result in the suppression of the large scale flow structures of the sludge-water interface thus providing a significant improvement in the SST performance. Furthermore, a critical value of the overflow rate (q(crit)) was found at which a pronounced large scale circulation pattern develops in the vertical plane, the density current in

  7. Influence of secondary settling tank performance on suspended solids mass balance in activated sludge systems.

    Science.gov (United States)

    Patziger, M; Kainz, H; Hunze, M; Józsa, J

    2012-05-01

    Secondary settling is the final step of the activated sludge-based biological waste water treatment. Secondary settling tanks (SSTs) are therefore an essential unit of producing a clear effluent. A further important function of SSTs is the sufficient thickening to achieve highly concentrated return sludge and biomass within the biological reactor. In addition, the storage of activated sludge is also needed in case of peak flow events (Ekama et al., 1997). Due to the importance of a high SST performance the problem has long been investigated (Larsen, 1977; Krebs, 1991; Takács et al., 1991; Ekama et al., 1997; Freimann, 1999; Patziger et al., 2005; Bürger et al., 2011), however, a lot of questions are still to solve regarding e.g. the geometrical features (inflow, outflow) and operations (return sludge control, scraper mechanism, allowable maximum values of surface overflow rates). In our study we focused on SSTs under dynamic load considering both the overall unsteady behaviour and the features around the peaks, investigating the effect of various sludge return strategies as well as the inlet geometry on SST performance. The main research tool was a FLUENT-based novel mass transport model consisting of two modules, a 2D axisymmetric SST model and a mixed reactor model of the biological reactor (BR). The model was calibrated and verified against detailed measurements of flow and concentration patterns, sludge settling, accompanied with continuous on-line measurement of in- and outflow as well as returned flow rates of total suspended solids (TSS) and water. As to the inlet arrangement a reasonable modification of the geometry could result in the suppression of the large scale flow structures of the sludge-water interface thus providing a significant improvement in the SST performance. Furthermore, a critical value of the overflow rate (q(crit)) was found at which a pronounced large scale circulation pattern develops in the vertical plane, the density current in

  8. Snowpack and snowmelt modeling of a subarctic catchment in northern Quebec, Canada, using an energy and mass balance approach

    Science.gov (United States)

    Oreiller, M.; Rousseau, A. N.; Minville, M.

    2012-12-01

    There is a growing interest in modeling snowpack evolution and spring runoff in northern Quebec, Canada, where there are several large-scale hydropower complexes. This region (49th to 55th degree north), characterized by boreal forest, lakes and wetlands, is highly remote and snowpack observations are very sparse. The objective of this study is to improve the snow module of HYDROTEL, a distributed continuous hydrological model currently used to predict inflows to large hydropower reservoirs of the region, with the help of continuous in-situ measurements of snow water equivalent. Up to now HYDROTEL has relied on a mixed degree-day/energy balance method to simulate accumulation and depletion of the snow cover. This approach has the advantage of requiring a small number of input data, but under changing climate conditions such as those recently experienced unusually high temperature in late winter or rain-on-snow events it has a tendency to generate unreliable results. We thus implemented a completely physically-based snow module, CROCUS, and try to determine whether HYDROTEL could benefit from an energy and mass balance approach. CROCUS, originally developed for snowpack simulations in the French Alps, has been adapted to the specific environmental characteristics of the boreal region. The simulation can now be validated with snow water equivalent collected by a GMON sensor, which evaluates absorption of the natural ground gamma radiation by the snowpack. The number of input data required by CROCUS is more important (seven meteorological variables on an hourly basis instead of two on a daily basis for the current version of HYDROTEL's snow module) which makes it more complex to use and at this points too complex to be implemented directly as a subroutine in HYDROTEL. However, this study shows that HYDROTEL is much more effective at predicting winter and spring runoff when using CROCUS as the snow module.

  9. Mass balance and life cycle assessment of the waste electrical and electronic equipment management system implemented in Lombardia Region (Italy).

    Science.gov (United States)

    Biganzoli, L; Falbo, A; Forte, F; Grosso, M; Rigamonti, L

    2015-08-15

    Waste electrical and electronic equipment (WEEE) is one of the fastest growing waste streams in Europe, whose content of hazardous substances as well as of valuable materials makes the study of the different management options particularly interesting. The present study investigates the WEEE management system in Lombardia Region (Italy) in the year 2011 by applying the life cycle assessment (LCA) methodology. An extensive collection of primary data was carried out to describe the main outputs and the energy consumptions of the treatment plants. Afterwards, the benefits and burdens associated with the treatment and recovery of each of the five categories in which WEEE is classified according to the Italian legislation (heaters and refrigerators - R1, large household appliances - R2, TV and monitors - R3, small household appliances - R4 and lighting equipment - R5) were evaluated. The mass balance of the treatment and recovery system of each of the five WEEE categories showed that steel and glass are the predominant streams of materials arising from the treatment; a non-negligible amount of plastic is also recovered, together with small amounts of precious metals. The LCA of the regional WEEE management system showed that the benefits associated with materials and energy recovery balance the burdens of the treatment processes, with the sole exception of two impact categories (human toxicity-cancer effects and freshwater ecotoxicity). The WEEE categories whose treatment and recovery resulted more beneficial for the environment and the human health are R3 and R5. The contribution analysis showed that overall the main benefits are associated with the recovery of metals, as well as of plastic and glass. Some suggestions for improving the performance of the system are given, as well as an indication for a more-in-depth analysis for the toxicity categories and a proposal for a new characterisation method for WEEE. PMID:25913003

  10. Catchment conceptualisation for examining applicability of chloride mass balance method in an area with historical forest clearance

    Directory of Open Access Journals (Sweden)

    H. Guan

    2010-07-01

    Full Text Available Of the various approaches for estimating groundwater recharge, the chloride mass balance (CMB method is one of the most frequently used, especially for arid and semiarid regions. Widespread native vegetation clearance, common in many areas globally, has changed the land surface boundary condition, posing the question as to whether the current system has reached new chloride equilibrium, required for a CMB application. Although a one-dimensional CMB can be applied at a point where the water and chloride fluxes are locally in steady state, the CMB method is usually applied at a catchment scale owing to significant lateral flows in mountains. The applicability of the CMB method to several conceptual catchment types of various chloride equilibrium conditions is examined. The conceptualisation, combined with some local climate conditions, is shown to be useful in assessing whether or not a catchment has reached new chloride equilibrium. The six conceptual catchment types are tested with eleven selected catchments in the Mount Lofty Ranges (MLR, a coastal hilly area in South Australia having experienced widespread historical forest clearance. The results show that six of the eleven catchments match a type VI chloride balance condition (chloride non-equilibrium with a gaining stream, with the ratios of stream chloride output (O over atmospheric chloride input (I, or catchment chloride O/I ratios, ranging from 2 to 4. Two catchments match a type V chloride balance condition (chloride non-equilibrium with a losing stream, with catchment chloride O/I ratios about 0.5. For these type V and type VI catchments, the CMB method is not applicable. The results also suggest that neither a chloride O/I ratio less than one nor a low seasonal fluctuation of streamflow chloride concentration (a factor below 4 guarantees a chloride equilibrium condition in the study area. A large chloride O/I value (above one and a large fluctuation of streamflow chloride

  11. Catchment conceptualisation for examining applicability of chloride mass balance method in an area of historical forest clearance

    Directory of Open Access Journals (Sweden)

    H. Guan

    2009-11-01

    Full Text Available Among various approaches for estimating groundwater recharge, chloride mass balance (CMB method is one of the most frequently used, in particular, for arid and semiarid regions. Widespread native vegetation clearance, common history in many areas globally, has changed land surface boundary condition, posing a question whether the current system has reached new chloride equilibrium for CMB application. To examine CMB applicability for catchments, conceptual catchment types of various chloride equilibrium conditions are defined. The conceptualization, combined with some local climate conditions, is demonstrated to be useful in examining whether a catchment has reached new chloride equilibrium. The six conceptual catchment types are tested with eleven selected catchments in the Mount Lofty Ranges (MLR, a coastal hilly area in South Australia having experienced historical widespread forest clearance. The results show that six of the eleven catchments match type VI chloride balance condition (chloride non-equilibrium with a gaining stream, with the ratio of stream chloride output over atmospheric chloride input (catchment chloride O/I ranging from 2 to 4. Two catchments match type V chloride balance condition (chloride non-equilibrium with a losing stream, with catchment chloride O/I values about 0.5. For these catchments, the CMB method is not appropriate to apply. The results also suggest that neither a below-one chloride O/I value nor a low seasonal fluctuation of streamflow chloride concentration (a factor below 4 guarantees a chloride equilibrium condition in the study area. But a large chloride O/I value (above one and a large fluctuation of streamflow chloride concentration (a factor of 10 and above generally indicates either a chloride disequilibrium, or cross-catchment water transfer, or both, for which CMB is not applicable. Based on the regression between chloride O/I values and annual precipitation for type VI catchments, a catchment with

  12. Ice flow dynamics and mass balance of Vatnajökull outlet glaciers observed by X-band SAR Data

    Science.gov (United States)

    Nagler, T.; Rott, H.; Magnússon, E.; Floricioiu, D.; Mueller, F.; Scharrer, K.

    2012-04-01

    Several outlet glaciers of the major ice caps in Iceland are affected by sub-glacial outburst floods, so-called jökulhlaups. Sources of these outbreaks are water accumulations beneath the glacier due to geothermal or volcanic activity. One component of the project NorthHydrology, carried out within the ESA STSE (Support to Science Element) programme, addresses techniques and applications of satellite data for studying drainage mechanisms and water outbreaks of sub-glacial lakes in Iceland. Such events are usually related to surface deformation and changes in ice velocities, sometimes occurring already well ahead of the peak of the flood wave. High resolution repeat pass SAR data are able to deliver spatially detailed information on surface motion and displacement, which are highly relevant for advancing the understanding of glacier hydraulics and jökulhlaup processes. A template matching technique is applied to data stacks of TerraSAR-X and Cosmo-SkyMed amplitude images acquired between summer 2008 to summer 2010 in order to study the ice dynamics and mass balance of outlet glaciers of Vatnajökull in Iceland. This technique requires distinct and stable surface features, as usually available on ice surfaces of glaciers. Main outlet glaciers, investigated in the project, are Breidamerkurjökull and Skeiderarjökull, with the fronts terminating close to the coast. The lower terminus of these glaciers exhibits significant melting during summer, and sometimes even during winter. At these glaciers in-situ data on ice velocity and surface elevation changes have been recorded at in situ GPS stations, operated by University of Iceland. The ice motion field was derived using ascending and descending repeat pass SAR images. In order to retrieve the 3D ice motion vector, effects of surface melt are taken into account by modelling the ablation. Combining maps of displacement shifts from ascending and descending passes and compensating for surface lowering due to melt, maps

  13. The ghost component of the mass balances at the Critical Zone scale: the chemical reactivity of immobile water

    Science.gov (United States)

    Nsir, K.; Mercury, L.; Azaroual, M.; Coquet, Y.

    2014-12-01

    The critical zone (CZ) is characterized by the duality between mass transport processes such as diffusion and flow of gases, fluids, and solids and localized bio-geochemical interactions especially linked to the "immobile" capillary/adsorbed water. Open questions are towards the role of capillarity onto reactive mechanisms: is there a geochemical signature of capillary water that can change the bio-geochemical balance? The research efforts focused on this issue to develop modeling tools integrating capillary effects at the soil-profile or CZ scale. Water suction gains geochemical significance when ranging from 20 to 200 MPa, meaning high tension and low amount of stretched water with its specific thermophysical properties (Mercury and Tardy, 2001; Mercury et al., 2003; 2004; Pettenati et al., 2008). Therefore, our interest is directed to the dry end of the water retention curve (WRC). The recent model from Silva and Grifoll (2007) proposed a full-range soil-water retention functions, extending the description to the adsorbed films down to the monolayer thickness. At this stage, it becomes possible to evaluate the role of both capillary pockets and adsorbed films at all water content in the geochemical dynamics of non-saturated soils. We developed from that point by fitting the WRC not through a continuous porous network, but through a decomposition into two porous domains (immobile/mobile domains), each with its own potential-water content law. This amounts to treat the WRC according to an intrinsic dual porosity scheme, and make easier to involve chemical effects at each potential-water content couple. A simple test simulation is developed with calcite rock kinetically interacting with immobile and mobile water, themselves connected by diffusive and advective gradients in the limits of the immobile-mobile contact area. The reactive transport simulations are run with HP1 (Jacques and Šimůnek, 2005). The mass balance exporting toward groundwater is calculated with

  14. A regional mass balance model based on total ammoniacal nitrogen for estimating ammonia emissions from beef cattle in Alberta Canada

    Science.gov (United States)

    Chai, Lilong; Kröbel, Roland; Janzen, H. Henry; Beauchemin, Karen A.; McGinn, Sean M.; Bittman, Shabtai; Atia, Atta; Edeogu, Ike; MacDonald, Douglas; Dong, Ruilan

    2014-08-01

    Animal feeding operations are primary contributors of anthropogenic ammonia (NH3) emissions in North America and Europe. Mathematical modeling of NH3 volatilization from each stage of livestock manure management allows comprehensive quantitative estimates of emission sources and nutrient losses. A regionally-specific mass balance model based on total ammoniacal nitrogen (TAN) content in animal manure was developed for estimating NH3 emissions from beef farming operations in western Canada. Total N excretion in urine and feces was estimated from animal diet composition, feed dry matter intake and N utilization for beef cattle categories and production stages. Mineralization of organic N, immobilization of TAN, nitrification, and denitrification of N compounds in manure, were incorporated into the model to account for quantities of TAN at each stage of manure handling. Ammonia emission factors were specified for different animal housing (feedlots, barns), grazing, manure storage (including composting and stockpiling) and land spreading (tilled and untilled land), and were modified for temperature. The model computed NH3 emissions from all beef cattle sub-classes including cows, calves, breeding bulls, steers for slaughter, and heifers for slaughter and replacement. Estimated NH3 emissions were about 1.11 × 105 Mg NH3 in Alberta in 2006, with a mean of 18.5 kg animal-1 yr-1 (15.2 kg NH3-N animal-1 yr-1) which is 23.5% of the annual N intake of beef cattle (64.7 kg animal-1 yr-1). The percentage of N intake volatilized as NH3-N was 50% for steers and heifers for slaughter, and between 11 and 14% for all other categories. Steers and heifers for slaughter were the two largest contributors (3.5 × 104 and 3.9 × 104 Mg, respectively) at 31.5 and 32.7% of total NH3 emissions because most growing animals were finished in feedlots. Animal housing and grazing contributed roughly 63% of the total NH3 emissions (feedlots, barns and pastures contributed 54.4, 0.2 and 8.1% of

  15. Antarctic ice-mass balance 2002 to 2011: regional re-analysis of GRACE satellite gravimetry measurements with improved estimate of glacial-isostatic adjustment

    Directory of Open Access Journals (Sweden)

    I. Sasgen

    2012-09-01

    Full Text Available We present regional-scale mass balances for 25 drainage basins of the Antarctic Ice Sheet (AIS from satellite observations of the Gravity and Climate Experiment (GRACE for the years 2002–2011. Satellite gravimetry estimates of the AIS mass balance are strongly influenced by mass movement in the Earth interior caused by ice advance and retreat during the last glacial cycle. Here, we develop an improved glacial-isostatic adjustment (GIA estimate for Antarctica using newly available GPS uplift rates, allowing us to more accurately separate GIA-induced trends in the GRACE gravity fields from those caused by current imbalances of the AIS. Our revised GIA estimate is considerably lower than previous predictions, yielding an (upper estimate of apparent mass change of 48 ± 18 Gt yr−1. Therefore, our AIS mass balance of −103 ± 23 Gt yr−1 is considerably less negative than previous GRACE estimates. The Northern Antarctic Peninsula and the Amundsen Sea Sector exhibit the largest mass loss (−25 ± 6 Gt yr−1 and −126 ± 11 Gt yr−1, respectively. In contrast, East Antarctica exhibits a slightly positive mass balance (19 ± 16 Gt yr−1, which is, however, mostly the consequence of compensating mass anomalies in Dronning Maud and Enderby Land (positive and Wilkes and George V Land (negative due to interannual accumulation variations. In total, 7% of the area constitute more than half of the AIS imbalance (53%, contributing −151 ± 9 Gt yr−1 to global mean sea-level change. Most of this imbalance is caused by long-term ice-dynamic speed up expected to prevail in the future.

  16. Simulating the climatic mass balance of Svalbard glaciers from 2003 to 2013 with a high-resolution coupled atmosphere-glacier model

    Directory of Open Access Journals (Sweden)

    K. S. Aas

    2015-10-01

    Full Text Available In this study we simulate the climatic mass balance of Svalbard glaciers with a coupled atmosphere-glacier model with 3 km grid spacing, from September 2003 to September 2013. We find a mean specific net mass balance of −167 mm w.e. yr−1, corresponding to a mean annual mass loss of about 5.7 Gt, with large interannual variability. Our results are compared with a comprehensive set of mass balance, meteorological and satellite measurements. Model temperature biases of 0.17 and −1.9 °C are found at two glacier automatic weather station sites. Simulated climatic mass balance is mostly within about 0.1 m w.e. yr−1 of stake measurements, and simulated winter accumulation at the Austfonna ice cap shows mean absolute errors of 0.05 and 0.06 m w.e. yr−1 when compared to radar-derived values for the selected years 2004 and 2006. Comparison of surface height changes from 2003 to 2008 from model, and satellite altimetry reveals good agreement in both mean values and regional differences. The largest deviations from observations are found for winter accumulation at Hansbreen (up to around 1 m w.e. yr−1, a site where sub-grid topography and wind redistribution of snow are important factors. Comparison with simulations using a 9 km grid spacing reveal considerable differences on regional and local scales. In addition, the 3 km grid spacing allows for a much more detailed comparison with observations than what is possible with a 9 km grid spacing. Further decreasing the grid spacing to 1 km appears to be less significant, although in general precipitation amounts increase with resolution. Altogether, the model compares well with observations and offers possibilities for studying glacier climatic mass balance on Svalbard both historically as well as based on climate projections.

  17. Volume changes of Vatnajökull ice cap, Iceland, due to surface mass balance, ice flow, and subglacial melting at geothermal areas

    DEFF Research Database (Denmark)

    Magnússon, Eyjólfur; Björnson, Helgi; Dall, Jørgen;

    2005-01-01

    We present observed changes in the geometry of western Vatnajökull over a period of about ten years which are caused by the surface mass balance, ice flow (both during surges and quiescent periods), and basal melting due to geothermal and volcanic activity. Comparison of two digital elevation...

  18. Future surface mass balance of the Antarctic ice sheet and its influence on sea level change, simulated by a regional atmospheric climate model

    NARCIS (Netherlands)

    Ligtenberg, S.R.M.; van de Berg, W.J.; van den Broeke, M.R.; Rae, J.G.L.; van Meijgaard, E.

    2013-01-01

    A regional atmospheric climate model with multi-layer snow module (RACMO2) is forced at the lateral boundaries by global climate model (GCM) data to assess the future climate and surface mass balance (SMB) of the Antarctic ice sheet (AIS). Two different GCMs (ECHAM5 until 2100 and HadCM3 until 2200)

  19. Occurrence and simulation of trihalomethanes in swimming pool water: A simple prediction method based on DOC and mass balance.

    Science.gov (United States)

    Peng, Di; Saravia, Florencia; Abbt-Braun, Gudrun; Horn, Harald

    2016-01-01

    Trihalomethanes (THM) are the most typical disinfection by-products (DBPs) found in public swimming pool water. DBPs are produced when organic and inorganic matter in water reacts with chemical disinfectants. The irregular contribution of substances from pool visitors and long contact time with disinfectant make the forecast of THM in pool water a challenge. In this work occurrence of THM in a public indoor swimming pool was investigated and correlated with the dissolved organic carbon (DOC). Daily sampling of pool water for 26 days showed a positive correlation between DOC and THM with a time delay of about two days, while THM and DOC didn't directly correlate with the number of visitors. Based on the results and mass-balance in the pool water, a simple simulation model for estimating THM concentration in indoor swimming pool water was proposed. Formation of THM from DOC, volatilization into air and elimination by pool water treatment were included in the simulation. Formation ratio of THM gained from laboratory analysis using native pool water and information from field study in an indoor swimming pool reduced the uncertainty of the simulation. The simulation was validated by measurements in the swimming pool for 50 days. The simulated results were in good compliance with measured results. This work provides a useful and simple method for predicting THM concentration and its accumulation trend for long term in indoor swimming pool water.

  20. Dual-core mass-balance approach for evaluating mercury and210Pb atmospheric fallout and focusing to lakes

    Science.gov (United States)

    Van Metre, P.C.; Fuller, C.C.

    2009-01-01

    Determining atmospheric deposition rates of mercury and other contaminants using lake sediment cores requires a quantitative understanding of sediment focusing. Here we present a novel approach that solves mass-balance equations for two cores algebraically to estimate contaminant contributions to sediment from direct atmospheric fallout and from watershed and in-lake focusing. The model is applied to excess 210Pb and Hg in cores from Hobbs Lake, a high-altitude lake in Wyoming. Model results for excess 210Pb are consistent with estimates of fallout and focusing factors computed using excess 210Pb burdens in lake cores and soil cores from the watershed and model results for Hg fallout are consistent with fallout estimated using the soil-core-based 210Pb focusing factors. The lake cores indicate small increases in mercury deposition beginning in the late 1800s and large increases after 1940, with the maximum at the tops of the cores of 16-20 ??g/m 2year. These results suggest that global Hg emissions and possibly regional emissions in the western United States are affecting the north-central Rocky Mountains. Hg fallout estimates are generally consistent with fallout reported from an ice core from the nearby Upper Fremont Glacier, but with several notable differences. The model might not work for lakes with complex geometries and multiple sediment inputs, but for lakes with simple geometries, like Hobbs, it can provide a quantitative approach for evaluating sediment focusing and estimating contaminant fallout.

  1. A Mass Balance Model for Designing Green Roof Systems that Incorporate a Cistern for Re-Use

    Directory of Open Access Journals (Sweden)

    Manoj Chopra

    2012-11-01

    Full Text Available Green roofs, which have been used for several decades in many parts of the world, offer a unique and sustainable approach to stormwater management. Within this paper, evidence is presented on water retention for an irrigated green roof system. The presented green roof design results in a water retention volume on site. A first principle mass balance computer model is introduced to assist with the design of these green roof systems which incorporate a cistern to capture and reuse runoff waters for irrigation of the green roof. The model is used to estimate yearly stormwater retention volume for different cistern storage volumes. Additionally, the Blaney and Criddle equation is evaluated for estimation of monthly evapotranspiration rates for irrigated systems and incorporated into the model. This is done so evapotranspiration rates can be calculated for regions where historical data does not exist, allowing the model to be used anywhere historical weather data are available. This model is developed and discussed within this paper as well as compared to experimental results.

  2. Aquifer Recharge Estimation through Atmospheric Chloride Mass Balance at Las Cañadas Caldera, Tenerife, Canary Islands, Spain

    Directory of Open Access Journals (Sweden)

    Rayco Marrero-Diaz

    2015-05-01

    Full Text Available The atmospheric chloride mass balance (CMB method was used to estimate net aquifer recharge in Las Cañadas Caldera, an endorheic summit aquifer area about 2000 m a.s.l. with negligible surface runoff, which hosts the largest freshwater reserve in Tenerife Island, Canary Islands, Spain. The wet hydrological year 2005–2006 was selected to compare yearly atmospheric chloride bulk deposition and average chloride content in recharge water just above the water table, both deduced from periodical sampling. The potential contribution of chloride to groundwater from endogenous HCl gas may invalidate the CMB method. The chloride-to-bromide molar ratio was an efficient tracer used to select recharge water samples having atmospheric origin of chloride. Yearly net aquifer recharge was 631 mm year−1, i.e., 69% of yearly precipitation. This result is in agreement with potential aquifer recharge estimated through an independent lumped-parameter rainfall-runoff model operated by the Insular Water Council of Tenerife. This paper illustrates basic procedures and routines to use the CMB method for aquifer recharge in active volcanic oceanic islands having sparse-data coverage and groundwater receiving contribution of endogenous halides.

  3. Present-day and future Antarctic ice sheet climate and surface mass balance in the Community Earth System Model

    Science.gov (United States)

    Lenaerts, Jan T. M.; Vizcaino, Miren; Fyke, Jeremy; van Kampenhout, Leo; van den Broeke, Michiel R.

    2016-09-01

    We present climate and surface mass balance (SMB) of the Antarctic ice sheet (AIS) as simulated by the global, coupled ocean-atmosphere-land Community Earth System Model (CESM) with a horizontal resolution of {˜ }1° in the past, present and future (1850-2100). CESM correctly simulates present-day Antarctic sea ice extent, large-scale atmospheric circulation and near-surface climate, but fails to simulate the recent expansion of Antarctic sea ice. The present-day Antarctic ice sheet SMB equals 2280 ± 131 {Gt year^{-1}}, which concurs with existing independent estimates of AIS SMB. When forced by two CMIP5 climate change scenarios (high mitigation scenario RCP2.6 and high-emission scenario RCP8.5), CESM projects an increase of Antarctic ice sheet SMB of about 70 {Gt year^{-1}} per degree warming. This increase is driven by enhanced snowfall, which is partially counteracted by more surface melt and runoff along the ice sheet's edges. This intensifying hydrological cycle is predominantly driven by atmospheric warming, which increases (1) the moisture-carrying capacity of the atmosphere, (2) oceanic source region evaporation, and (3) summer AIS cloud liquid water content.

  4. Anthropogenic impact on Antarctic surface mass balance, currently masked by natural variability, to emerge by mid-century

    Science.gov (United States)

    Previdi, Michael; Polvani, Lorenzo M.

    2016-09-01

    Global and regional climate models robustly simulate increases in Antarctic surface mass balance (SMB) during the twentieth and twenty-first centuries in response to anthropogenic global warming. Despite these robust model projections, however, observations indicate that there has been no significant change in Antarctic SMB in recent decades. We show that this apparent discrepancy between models and observations can be explained by the fact that the anthropogenic climate change signal during the second half of the twentieth century is small compared to the noise associated with natural climate variability. Using an ensemble of 35 global coupled climate models to separate signal and noise, we find that the forced SMB increase due to global warming in recent decades is unlikely to be detectable as a result of large natural SMB variability. However, our analysis reveals that the anthropogenic impact on Antarctic SMB is very likely to emerge from natural variability by the middle of the current century, thus mitigating future increases in global sea level.

  5. Cross check of the new economic and mass balance features of the fuel cycle scenario code TR_EVOL

    Directory of Open Access Journals (Sweden)

    Merino-Rodríguez Iván

    2016-01-01

    Full Text Available Versatile computational tools with up to date capabilities are needed to assess current nuclear fuel cycles or the transition from the current status of the fuel cycle to the more advanced and sustainable ones. This work is intended to cross check the new capabilities of the fuel cycle scenario code TR_EVOL. This process has been divided in two stages. The first stage is dedicated to check the improvements in the nuclear fuel mass balance estimation using the available data for the Spanish nuclear fuel cycle. The second stage has been focused in verifying the validity of the TR_EVOL economic module, comparing results to data published by the ARCAS EU project. A specific analysis was required to evaluate the back-end cost. Data published by the waste management responsible institutions was used for the validation of the methodology. Results were highly satisfactory for both stages. In particular, the economic assessment provides a difference smaller than 3% regarding results published by the ARCAS project (NRG estimations. Furthermore, concerning the back-end cost, results are highly acceptable (7% difference for a final disposal in a once-through scenario and around 11% for a final disposal in a reprocessing strategy given the significant uncertainties involved in design concepts and related unit costs.

  6. Septic systems as hot-spots of pollutants in the environment: Fate and mass balance of micropollutants in septic drainfields.

    Science.gov (United States)

    Yang, Yun-Ya; Toor, Gurpal S; Wilson, P Chris; Williams, Clinton F

    2016-10-01

    Septic systems, a common type of onsite wastewater treatment systems, can be an important source of micropollutants in the environment. We investigated the fate and mass balance of 17 micropollutants, including wastewater markers, hormones, pharmaceuticals and personal care products (PPCPs) in the drainfield of a septic system. Drainfields were replicated in lysimeters (1.5m length, 0.9m width, 0.9m height) and managed similar to the field practice. In each lysimeter, a drip line dispersed 9L of septic tank effluent (STE) per day (equivalent to 32.29L/m(2) per day). Fourteen micropollutants in the STE and 12 in the leachate from drainfields were detected over eight months. Concentrations of most micropollutants in the leachate were low (85% of the added micropollutants except for sucralose were attenuated in the drainfield. We discovered that sorption was the key mechanism for retention of carbamazepine and partially for sulfamethoxazole, whereas microbial degradation likely attenuated acetaminophen in the drainfield. This data suggests that sorption and microbial degradation limited transport of micropollutants from the drainfields. However, the leaching of small amounts of micropollutants indicate that septic systems are hot-spots of micropollutants in the environment and a better understanding of micropollutants in septic systems is needed to protect groundwater quality. PMID:27312276

  7. Coupling of climate models and ice sheet models by surface mass balance gradients: application to the Greenland Ice Sheet

    Directory of Open Access Journals (Sweden)

    M. M. Helsen

    2012-03-01

    Full Text Available It is notoriously difficult to couple surface mass balance (SMB results from climate models to the changing geometry of an ice sheet model. This problem is traditionally avoided by using only accumulation from a climate model, and parameterizing the meltwater run-off as a function of temperature, which is often related to surface elevation (Hs. In this study, we propose a new strategy to calculate SMB, to allow a direct adjustment of SMB to a change in ice sheet topography and/or a change in climate forcing. This method is based on elevational gradients in the SMB field as computed by a regional climate model. Separate linear relations are derived for ablation and accumulation, using pairs of Hs and SMB within a minimum search radius. The continuously adjusting SMB forcing is consistent with climate model forcing fields, also for initially non-glaciated areas in the peripheral areas of an ice sheet. When applied to an asynchronous coupled ice sheet – climate model setup, this method circumvents traditional temperature lapse rate assumptions. Here we apply it to the Greenland Ice Sheet (GrIS. Experiments using both steady-state forcing and glacial-interglacial forcing result in realistic ice sheet reconstructions.

  8. Chemical mass balance estimation of arsenic in atmospheric dust fall out in an urban residential area, Raipur, Central India

    Directory of Open Access Journals (Sweden)

    G. Balakrishna

    2010-11-01

    Full Text Available The components and quantities of atmospheric dust fallout have been reported to be the pollution indicator of large urban areas. The multiplicity and complexity of sources of atmospheric dusts in urban regions has put forward the need of source apportionment of these sources indicating their contribution to specific environmental receptor. The study presented here is focused on investigation of source contribution estimates of Arsenic in urban dust fallout in an urban-industrial area, Raipur, India. Source-receptor based representative sampling plan using longitudinal study design has been adopted. Six sampling sites have been identified on the basis of land use for development plan of anthropogenic activities and factors related to the transportation and dispersion pattern of atmospheric dusts. Source apportionment has been done using Chemical Mass Balance (CMB 8. Good fit parameters and relative source contribution has been analyzed and documented. Dominance of coal fired industries sources on arsenic levels measured at selected ambient residential receptors compared to line sources has been observed. Road-traffic has shown highest contribution of dust at indoor houses and out door-street automobile exhaust has shows highest contribution for arsenic. The results of CMB output and regression data of source-receptor dust matrices have shown comparable pattern.

  9. Titanium Mass-balance Analysis of Paso Robles Soils: Elemental Gains and Losses as Affected by Acid Alteration Fluids

    Science.gov (United States)

    Sutter, Brad; Ming, Douglas W.

    2010-01-01

    The Columbia Hills soils have been exposed to aqueous alteration in alkaline [1] as well as acid conditions [2,3]. The Paso Robles class soils are bright soils that possess the highest S concentration of any soil measured on Mars [2]. Ferric-sulfate detection by Moessbauer analysis indicated that acid solutions were involved in forming these soils [4]. These soils are proposed to have formed by alteration of nearby rock by volcanic hydrothermal or fumarolic activity. The Paso Robles soils consist of the original Paso Robles-disturbed-Pasadena (PR-dist), Paso Robles- PasoLight (PR-PL), Arad-Samra, Arad-Hula, Tyrone- Berker Island1 and Tyrone-MountDarwin [2 ,3. ]Chemical characteristics indicate that the PR-dist and PR-PL soils could be derived from acid weathering of local Wishstone rocks while the Samra and Hula soils are likely derived from local Algonquin-Iroquet rock [3]. The Paso Robles soils were exposed to acidic sulfur bearing fluids; however, little else is known about the chemistry of the alteration fluid and its effects on the alteration of the proposed parent materials. The objectives of this work are to conduct titanium normalized mass-balance analysis to1) assess elemental gains and losses from the parent materials in the formation of the Paso Robles soils and 2) utilize this information to indicate the chemical nature of the alteration fluids.

  10. The Alteration History of Clovis Class Rocks in Gusev Crater as Determined by Ti-Normalzed Mass Balance Analysis

    Science.gov (United States)

    Sutter, Brat; Ming, Douglas W.; Niles, P. B.; Golden, D. C.

    2012-01-01

    The West Spur Clovis class rocks in Gusev Crater are some of the most altered rocks in Gusev Crater and likely contain a mixed sulfate and phyllosilicate mineralogy [1,2]. The high S and Cl content of the Clovis rocks suggests that acidic vapors or fluids of H2SO4 and HCl reacted with the Clovis parent rock to form Ca, Mg,- sulfates, iron-oxyhydroxides and secondary aluminosilicates (approx.60 wt.%) of a poorly crystalline nature (e.g., allophane) [1]. Up to 14-17 wt.% phyllosilicates (e.g., kaolinite, chlorite, serpentine) are hypothesized to exist in the Clovis materials suggesting that Clovis parent materials while possibly exposed to acidic pHs were likely neutralized by basalt dissolution which resulted in mildly acidic pHs (4-6) [1, 2]. This work proposes that subsequent to the alteration of the Clovis rocks, alteration fluids became concentrated in ions resulting in the addition of silicate and salts. The objective of this work is to utilize Ti-normalized mass balance analysis to evaluate (1) mineral gains and losses and (2) elemental gains and losses in the Clovis rocks. Results of this work will be used evaluate the nature of geochemical conditions that affect phyllosilicate and sulfate formation at Gusev crater.

  11. Biomethanation of vegetable market waste in an anaerobic baffled reactor: Effect of effluent recirculation and carbon mass balance analysis.

    Science.gov (United States)

    Gulhane, Madhuri; Khardenavis, Anshuman A; Karia, Sneha; Pandit, Prabhakar; Kanade, Gajanan S; Lokhande, Satish; Vaidya, Atul N; Purohit, Hemant J

    2016-09-01

    In the present study, feasibility of biomethanation of vegetable market waste in a 4-chambered anaerobic baffled reactor (ABR) was investigated at 30d hydraulic retention time and organic loading rate of 0.5gVS/L/d for one year. Indicators of process stability viz., butyrate/acetate and propionate/acetate ratios were consistent with phase separation in the different chambers, which remained unaltered even during recirculation of effluent. Chemical oxygen demand (COD) and volatile solids (VS) removal efficiencies were observed to be consistently high (above 90%). Corresponding biogas and methane yields of 0.7-0.8L/g VS added/d and 0.42-52L/g VS added/d respectively were among the highest reported in case of AD of vegetable waste in an ABR. Process efficiency of the ABR for vegetable waste methanation, which is indicated by carbon recovery factor showed that, nearly 96.7% of the input carbon considered for mass balance was accounted for in the product. PMID:27133362

  12. Evaluating the potential for environmental pollution from chromated copper arsenate (CCA)-treated wood waste: a new mass balance approach.

    Science.gov (United States)

    Mercer, T G; Frostick, L E

    2014-07-15

    The potential for pollution from arsenic, chromium and copper in chromated copper arsenate (CCA) treated wood waste was assessed using two lysimeter studies. The first utilised lysimeters containing soil and CCA wood waste mulch exposed to natural conditions over a five month period. The second study used the same lysimeter setup in a regulated greenhouse setting with a manual watering regime. Woodchip, soil and leachate samples were evaluated for arsenic, chromium and copper concentrations. Resultant concentration data were used to produce mass balances, an approach thus far unused in such studies. This novel analysis revealed new patterns of mobility and distribution of the elements in the system. The results suggest that CCA wood waste tends to leach on initial exposure to a leachant and during weathering of the wood. When in contact with soil, metal(loid) transport is reduced due to complexation reactions. With higher water application or where the adsorption capacity of the soil is exceeded, the metal(loid)s are transported through the soil column as leachate. Overall, there was an unexplained loss of metal(loid)s from the system that might be attributed to volatilisation of arsenic and plant uptake. This suggests a hitherto unidentified risk to both the environment and human health. PMID:24858049

  13. Technical note: An improved estimate of uncertainty for source contribution from effective variance Chemical Mass Balance (EV-CMB) analysis

    Science.gov (United States)

    Shi, Guo-Liang; Zhou, Xiao-Yu; Feng, Yin-Chang; Tian, Ying-Ze; Liu, Gui-Rong; Zheng, Mei; Zhou, Yang; Zhang, Yuan-Hang

    2015-01-01

    The CMB (Chemical Mass Balance) 8.2 model released by the USEPA is a commonly used receptor model that can determine estimated source contributions and their uncertainties (called default uncertainty). In this study, we propose an improved CMB uncertainty for the modeled contributions (called EV-LS uncertainty) by adding the difference between the modeled and measured values for ambient species concentrations to the default CMB uncertainty, based on the effective variance least squares (EV-LS) solution. This correction reconciles the uncertainty estimates for EV and OLS regression. To verify the formula for the EV-LS CMB uncertainty, the same ambient datasets were analyzed using the equation we developed for EV-LS CMB uncertainty and a standard statistical package, SPSS 16.0. The same results were obtained by both ways indicate that the equation for EV-LS CMB uncertainty proposed here is acceptable. In addition, four ambient datasets were studies by CMB 8.2 and the source contributions as well as the associated uncertainties were obtained accordingly.

  14. Chemical and sewage sludge co-incineration in a full-scale MSW incinerator: toxic trace element mass balance.

    Science.gov (United States)

    Biganzoli, Laura; Grosso, Mario; Giugliano, Michele; Campolunghi, Manuel

    2012-10-01

    Co-incineration of sludges with MSW is a quite common practice in Europe. This paper illustrates a case of co-incineration of both sewage sludges and chemical sludges, the latter obtained from drinking water production, in a waste-to-energy (WTE) plant located in northern Italy and equipped with a grate furnace, and compares the toxic trace elements mass balance with and without the co-incineration of sludges. The results show that co-incineration of sewage and chemical sludges does not result in an increase of toxic trace elements the total release in environment, with the exception of arsenic, whose total release increases from 1 mg t(fuel) (-1) during standard operation to 3 mg t(fuel) (-1) when sludges are co-incinerated. The increase of arsenic release is, however, attributable to the sole bottom ashes, where its concentration is five times higher during sludge co-incineration. No variation is observed for arsenic release at the stack. This fact is a further guarantee that the co-incineration of sludges, when performed in a state-of-the-art WTE plant, does not have negative effects on the atmospheric environment. PMID:22584266

  15. The effect of adjusting model inputs to achieve mass balance on time-dynamic simulations in a food-web model of Lake Huron

    Science.gov (United States)

    Langseth, Brian J.; Jones, Michael L.; Riley, Stephen C.

    2014-01-01

    Ecopath with Ecosim (EwE) is a widely used modeling tool in fishery research and management. Ecopath requires a mass-balanced snapshot of a food web at a particular point in time, which Ecosim then uses to simulate changes in biomass over time. Initial inputs to Ecopath, including estimates for biomasses, production to biomass ratios, consumption to biomass ratios, and diets, rarely produce mass balance, and thus ad hoc changes to inputs are required to balance the model. There has been little previous research of whether ad hoc changes to achieve mass balance affect Ecosim simulations. We constructed an EwE model for the offshore community of Lake Huron, and balanced the model using four contrasting but realistic methods. The four balancing methods were based on two contrasting approaches; in the first approach, production of unbalanced groups was increased by increasing either biomass or the production to biomass ratio, while in the second approach, consumption of predators on unbalanced groups was decreased by decreasing either biomass or the consumption to biomass ratio. We compared six simulation scenarios based on three alternative assumptions about the extent to which mortality rates of prey can change in response to changes in predator biomass (i.e., vulnerabilities) under perturbations to either fishing mortality or environmental production. Changes in simulated biomass values over time were used in a principal components analysis to assess the comparative effect of balancing method, vulnerabilities, and perturbation types. Vulnerabilities explained the most variation in biomass, followed by the type of perturbation. Choice of balancing method explained little of the overall variation in biomass. Under scenarios where changes in predator biomass caused large changes in mortality rates of prey (i.e., high vulnerabilities), variation in biomass was greater than when changes in predator biomass caused only small changes in mortality rates of prey (i.e., low

  16. Estimating Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

    Directory of Open Access Journals (Sweden)

    X. Fettweis

    2012-08-01

    Full Text Available We report future projections of Surface Mass Balance (SMB over the Greenland ice sheet (GrIS obtained with the regional climate model MAR, forced by the outputs of three CMIP5 General Circulation Models (GCMs when considering two different warming scenarios (RCP 4.5 and RCP 8.5. The GCMs selected in this study have been chosen according to their ability to simulate the current climate over Greenland. Our results indicate that in a warmer climate (i the mass gained due to increased precipitation over GrIS does not compensate the mass lost through increased run-off; (ii the surface melt increases non-linearly with rising temperatures due to the positive feedback between surface albedo and melt, associated with the expansion of bare ice zones which, in addition, decreases the ice sheet refreezing capacity; (iii most of the precipitation is expected to fall as rainfall in summer, which further increases surface melt; (iv no considerable change is expected on the length of the melting season, since heavier winter snowfall dampens the melt increase at the end of spring; (v the increase of meltwater run-off versus temperature anomalies is dependent of the GCM-forced MAR ability to simulate the current climate; (vi the MAR-simulated SMB changes can be approximated using the annual accumulated snowfall and summer 600 hPa temperature increase simulated by the forcing GCMs. In view of the large range in the CMIP5 future projections for the same future scenario, the GCM-based SMB approximations allow us to estimate what future projections are most likely within the CMIP5 multi-model ensemble. In 2100, the ensemble mean projects a sea level rise, resulting from a GrIS SMB decrease, estimated to be +4 ± 2 cm and +9 ± 4 cm for the RCP 4.5 and RCP 8.5 scenarios, respectively. The GrIS SMB should remain positive with respect to RCP 4.5 scenario and becomes negative around 2070 in the case of the RCP 8.5 scenario since a global warming >+3 °C is needed

  17. Assessing the potential contribution of blowing snow to the mass balance of glaciers in the Cariboo Mountains of British Columbia, Canada

    Science.gov (United States)

    Yadghar, A.; Ainslie, B.; Jackson, P. L.; Dery, S. J.

    2009-05-01

    The difference between snow accumulation and ice ablation determines the mass balance of glaciers, with snowfall as the dominant input. However, blowing snow is another important term in glacier mass balance. Blowing snow occurs when loose particles of snow at the surface are entrained by winds exceeding a certain threshold for transport. The role of blowing snow in the surface mass balance of glaciers in the Cariboo Mountains (the northern extension of the Columbia Mountains) of British Columbia, Canada is assessed in this study. The regional atmospheric modeling system (RAMS) model is used to simulate several case studies of blowing snow in the region of interest. The simulations are validated with meteorological data from a mesoscale network (mesonet) of high-elevation automatic weather stations (AWSs) entitled the Cariboo Alpine Mesonet (CAMnet) that has been developed in the region since 2006. The mass divergence (convergence) fields from the RAMS simulations provide an indication of the blowing snow erosion (accumulation) areas. These are then compared with the spatial distribution of glaciers in the Cariboo Mountains. Our results suggest that snow drift may contribute significantly to the mass budget of glaciers in the region.

  18. Analysis of the ecosystem structure of Laguna Alvarado, western Gulf of Mexico, by means of a mass balance model

    Science.gov (United States)

    Cruz-Escalona, V. H.; Arreguín-Sánchez, F.; Zetina-Rejón, M.

    2007-03-01

    Alvarado is one of the most productive estuary-lagoon systems in the Mexican Gulf of Mexico. It has great economic and ecological importance due to high fisheries productivity and because it serves as a nursery, feeding, and reproduction area for numerous populations of fishes and crustaceans. Because of this, extensive studies have focused on biology, ecology, fisheries (e.g. shrimp, oysters) and other biological components of the system during the last few decades. This study presents a mass-balanced trophic model for Laguna Alvarado to determine it's structure and functional form, and to compare it with similar coastal systems of the Gulf of Mexico and Mexican Pacific coast. The model, based on the software Ecopath with Ecosim, consists of eighteen fish groups, seven invertebrate groups, and one group each of sharks and rays, marine mammals, phytoplankton, sea grasses and detritus. The acceptability of the model is indicated by the pedigree index (0.5) which range from 0 to 1 based on the quality of input data. The highest trophic level was 3.6 for marine mammals and snappers. Total system throughput reached 2680 t km -2 year -1, of which total consumption made up 47%, respiratory flows made up 37% and flows to detritus made up 16%. The total system production was higher than consumption, and net primary production higher than respiration. The mean transfer efficiency was 13.8%. The mean trophic level of the catch was 2.3 and the primary production required to sustain the catch was estimated in 31 t km -2 yr -1. Ecosystem overhead was 2.4 times the ascendancy. Results suggest a balance between primary production and consumption. In contrast with other Mexican coastal lagoons, Laguna Alvarado differs strongly in relation to the primary source of energy; here the primary producers (seagrasses) are more important than detritus pathways. This fact can be interpreted a response to mangrove deforest, overfishing, etc. Future work might include the compilation of

  19. Application of mass and energy balance regularities in fermentation. Reprinted from Biotechnology and Bioengineering, Vol. XX, No. 10, Pages 1595-1621 (1978).

    Science.gov (United States)

    Erickson, L E; Minkevich, I G; Eroshin, V K

    2000-03-20

    Material and energy balances for fermentation processes are developed based on the facts that the heat of reaction per electron transferred to oxygen for a wide variety of organic molecules, the number of available electrons per carbon atom in biomass, and the weight fraction carbon in biomass are relatively constant. Mass-energy balance equations are developed which relate the biomass energetic yield coefficient to sets of variables which may be determined experimentally. Organic substrate consumption, biomass production, oxygen consumption, carbon dioxide production, heat evolution, and nitrogen consumption are considered as measured variables. Application of the balances using direct and indirect methods of yield coefficient estimation is illustrated using experimental results from the literature. Product formation is included in the balance equations and the effect of product formation on biomass yield estimates is examined. Application of mass-energy balances in the optimal operation of continuous single-cell protein production facilities is examined, and the variation of optimal operating conditions with changes in yield are illustrated for methanol as organic substrate.

  20. Improved determination of dynamic balance using the centre of mass and centre of pressure inclination variables in a complete golf swing cycle.

    Science.gov (United States)

    Choi, Ahnryul; Sim, Taeyong; Mun, Joung Hwan

    2016-01-01

    Golf requires proper dynamic balance to accurately control the club head through a harmonious coordination of each human segment and joint. In this study, we evaluated the ability for dynamic balance during a golf swing by using the centre of mass (COM)-centre of pressure (COP) inclination variables. Twelve professional, 13 amateur and 10 novice golfers participated in this study. Six infrared cameras, two force platforms and SB-Clinic software were used to measure the net COM and COP trajectories. In order to evaluate dynamic balance ability, the COM-COP inclination angle, COM-COP inclination angular velocity and normalised COM-COP inclination angular jerk were used. Professional golfer group revealed a smaller COM-COP inclination angle and angular velocity than novice golfer group in the lead/trail direction (P < 0.01). In the normalised COM-COP inclination angular jerk, the professional golfer group showed a lower value than the other two groups in all directions. Professional golfers tend to exhibit improved dynamic balance, and this can be attributed to the neuromusculoskeletal system that maintains balance with proper postural control. This study has the potential to allow for an evaluation of the dynamic balance mechanism and will provide useful basic information for swing training and prevention of golf injuries. PMID:26264189

  1. Water stable isotope tracers in the Blautopf catchment (southern Germany) linked to a mass balance of polyaromatic hydrocarbons

    International Nuclear Information System (INIS)

    Full text: In a pollutant mass balance on the Blautopf Catchment ('Schwaebische Alb', Southern Germany), we observed retention by soils of more than 82 % of the atmospherically deposited polyaromatic hydrocarbons. Furthermore, the largest fluxes of the transported pollutants were detected in the Blautopf discharge during peak runoff such as after snow melt events. To understand the hydrology of the system, we studied the dynamics of water discharge of the catchment using stable isotopes (δ18O and δ2H) in precipitation, cave seepage and the Blautopf spring. The latter is the only outlet of the system and represents the groundwater, which shows a highly variable discharge (0.3 to 32 m3 s-1) as expected for fast responsive karst systems. Isotopically, the rainfall showed a seasonal cycle with δ18O values between -2.6 and -22.6 permille during summer and winter, respectively. In contrast to this, the isotopic signals of the cave seepage water and the discharge seemed completely buffered and ranged around an average δ18O value of -10 permille. This value also closely matched the amount weighted average of the precipitation. The isotopic similarity between cave seepage and discharge water indicated that most of the mixing already occurred in the vadose zone that has up to 150 meters of thickness. The latter can be divided into the compartments soil, epikarst and rock matrix that all have good storage capacities. The method revealed new aspects about the flow paths and mixing of the infiltrated water and associated pollutants and helped constrain the risk to the local groundwater. (author)

  2. The Greenland ice sheet: modelling the surface mass balance from GCM output with a new statistical downscaling technique

    Directory of Open Access Journals (Sweden)

    M. Geyer

    2013-06-01

    Full Text Available The aim of this study is to derive a realistic estimation of the Surface Mass Balance (SMB of the Greenland ice sheet (GrIS through statistical downscaling of Global Coupled Model (GCM outputs. To this end, climate simulations performed with the CNRM-CM5.1 Atmosphere-Ocean GCM within the CMIP5 (Coupled Model Intercomparison Project phase 5 framework are used for the period 1850–2300. From the year 2006, two different emission scenarios are considered (RCP4.5 and RCP8.5. Simulations of SMB performed with the detailed snowpack model Crocus driven by CNRM-CM5.1 surface atmospheric forcings serve as a reference. On the basis of these simulations, statistical relationships between total precipitation, snow-ratio, snowmelt, sublimation and near-surface air temperature are established. This leads to the formulation of SMB variation as a function of temperature variation. Based on this function, a downscaling technique is proposed in order to refine 150 km horizontal resolution SMB output from CNRM-CM5.1 to a 15 km resolution grid. This leads to a much better estimation of SMB along the GrIS margins, where steep topography gradients are not correctly represented at low-resolution. For the recent past (1989–2008, the integrated SMB over the GrIS is respectively 309 and 243 Gt yr–1 for raw and downscaled CNRM-CM5.1. In comparison, the Crocus snowpack model forced with ERA-Interim yields a value of 245 Gt yr–1. The major part of the remaining discrepancy between Crocus and downscaled CNRM-CM5.1 SMB is due to the different snow albedo representation. The difference between the raw and the downscaled SMB tends to increase with near-surface air temperature via an increase in snowmelt.

  3. An investigation into the sensitivity of the atmospheric chlorine and bromine loading using a globally averaged mass balance model

    Science.gov (United States)

    Dowdell, David C.; Matthews, G. Peter; Wells, Ian

    Two globally averaged mass balance models have been developed to investigate the sensitivity and future level of atmospheric chlorine and bromine as a result of the emission of 14 chloro- and 3 bromo-carbons. The models use production, growth, lifetime and concentration data for each of the halocarbons and divide the production into one of eight uses, these being aerosol propellants, cleaning agents, blowing agents in open and closed cell foams, non-hermetic and hermetic refrigeration, fire retardants and a residual "other" category. Each use category has an associated emission profile which is built into the models to take into account the proportion of halocarbon retained in equipment for a characteristic period of time before its release. Under the Montreal Protocol 3 requirements, a peak chlorine loading of 3.8 ppb is attained in 1994, which does not reduce to 2.0 ppb (the approximate level of atmospheric chlorine when the ozone hole formed) until 2053. The peak bromine loading is 22 ppt, also in 1994, which decays to 12 ppt by the end of next century. The models have been used to (i) compare the effectiveness of Montreal Protocols 1, 2 and 3 in removing chlorine from the atmosphere, (ii) assess the influence of the delayed emission assumptions used in these models compared to immediate emission assumptions used in previous models, (iii) assess the relative effect on the chlorine loading of a tightening of the Montreal Protocol 3 restrictions, and (iv) calculate the influence of chlorine and bromine chemistry as well as the faster phase out of man-made methyl bromide on the bromine loading.

  4. Quantifying Salinization of the Upper-Middle Rio Grande Using a Basin-Scale Water and Chloride Mass Balance Model

    Science.gov (United States)

    Mills, S. K.; Phillips, F. M.; Hogan, J. F.; Hendrickx, J. M.

    2002-12-01

    The Rio Grande is clearly undergoing salinization, manifested by a 50-fold increase in total dissolved solids content between its headwaters in Colorado and the U.S.-Mexico border. To elucidate the causes of this salinization, we conducted an eight-day synoptic sampling campaign in August 2001. This sampling included the river, its major tributaries, and major irrigation drain inflows. Along 1200 km between the river headwaters in Colorado and Fort Quitman, Texas, we collected 110 water samples with an average interval of ~10 km between sampling locales. In the laboratory, samples were analyzed for major constituents including chloride, as well as for bromide and the 36Cl/Cl ratio. Isotopic fingerprinting using the 36Cl/Cl ratio indicates that meteoric waters and deep sedimentary brines respectively account for most of the water and most of the salt inflow to the Rio Grande. The meteoric end member has a 36Cl/Cl ratio of 1100 and a Cl/Br ratio of 30; the brine end member has a 36Cl/Cl ratio of 35 and a Cl/Br ratio of 1150. Using these end member chemistries with USGS stream flow gauging data, we constructed a water- and salt- instantaneous mass balance model of the Rio Grande for the eight-day sampling interval. This model indicates that most water losses from the Rio Grande are due to evaporation from Elephant Butte reservoir, open water evaporation from irrigation ditches, and evapotranspiration of riparian and ditch-bank vegetation. The model also emphasizes the significance of salt input due to deep brine discharge to the river, particularly at the downstream ends of local sedimentary basins of the Rio Grande rift. The Rio Grande receives a smaller amount of salt from saline drains near El Paso, which may be acquiring salt from deep brine discharge as they cross over faults or other structural fluid conduits.

  5. Using a mass balance to understand the geology and geochemistry of a reservoir receiving and discharging acid mine drainage

    International Nuclear Information System (INIS)

    Howard-Williams Lake is a 14.5 acre reservoir located in an abandoned coal mine in Perry County, Ohio. With a pH of 3.0 and acidity values of 300--400 mg/L, the reservoir has no plants or fish currently surviving in the lake. Reclamation of spoil piles adjacent to the lake to the north in the late 1980s was not successful in reducing the acidity of the lake. Currently, papermill sludge is being used on the reclaimed area to the north to promote vegetation, but the reservoir has shown no signs of improving. The goal of this project is to transform the lake into a fishable and swimmable one. The reservoir is receiving about 175 gallons per minute of acid mine drainage, not including seepage into the lake, from eight different sources. Three of the sources account for about 165 gallons per minute of the surface water that enters the lake. These inflows have relatively low acidity readings, which range from 66 mg/L to 568 mg/L. The other five sources of acid mine drainage have much lower flowrates, but have acidity values as high as 3,000 mg/L. Samples of all of the surface inflows and the outflow of the lake were taken and sent to a laboratory and tested for the following parameters: total acidity as CaCO3, total alkalinity as CaCO2, specific conductivity, total suspended solids, sulfate, chloride calcium, magnesium, sodium, potassium, total iron, total manganese, aluminum, and hardness. During sampling of the surface inflows, volumetric flowrates were measured for each inflow. Once the flowrates and the concentrations of the various parameters were known, a mass balance could be constructed which would show how much of each parameter was entering the lake each day. These data were then used to gain an understanding of the geochemistry and geology of the site

  6. Trace element mass balance in hydrous adiabatic mantle melting: The Hydrous Adiabatic Mantle Melting Simulator version 1 (HAMMS1)

    Science.gov (United States)

    Kimura, Jun-Ichi; Kawabata, Hiroshi

    2014-06-01

    numerical mass balance calculation model for the adiabatic melting of a dry to hydrous peridotite has been programmed in order to simulate the trace element compositions of basalts from mid-ocean ridges, back-arc basins, ocean islands, and large igneous provinces. The Excel spreadsheet-based calculator, Hydrous Adiabatic Mantle Melting Simulator version 1 (HAMMS1) uses (1) a thermodynamic model of fractional adiabatic melting of mantle peridotite, with (2) the parameterized experimental melting relationships of primitive to depleted mantle sources in terms of pressure, temperature, water content, and degree of partial melting. The trace element composition of the model basalt is calculated from the accumulated incremental melts within the adiabatic melting regime, with consideration for source depletion. The mineralogic mode in the primitive to depleted source mantle in adiabat is calculated using parameterized experimental results. Partition coefficients of the trace elements of mantle minerals are parameterized to melt temperature mostly from a lattice strain model and are tested using the latest compilations of experimental results. The parameters that control the composition of trace elements in the model are as follows: (1) mantle potential temperature, (2) water content in the source mantle, (3) depth of termination of adiabatic melting, and (4) source mantle depletion. HAMMS1 enables us to obtain the above controlling parameters using Monte Carlo fitting calculations and by comparing the calculated basalt compositions to primary basalt compositions. Additionally, HAMMS1 compares melting parameters with a major element model, which uses petrogenetic grids formulated from experimental results, thus providing better constraints on the source conditions.

  7. Variability in New Shortening Estimates from Southern Peru (12-14S); Implications for Mass Balance of the Andean Plateau.

    Science.gov (United States)

    Gotberg, N.; McQuarrie, N.

    2008-12-01

    One of the fundamental questions of interest with regards to the Andean Plateau is the mass balance of material needed to create and sustain a 3-4 km high plateau. Is crustal shortening sufficient to support an isostatically compensated crust of 60-70km? We present new estimates of shortening across the northern margin of the Andean Plateau. The cross section extent, from the eastern edge of the volcanic arc to foreland basin, is approximately one half of the physiographic width of the Andean Plateau in Peru. Cross sectional shortening estimates in southern Peru (12-14°S) provide a best estimate of 123 km or 40% shortening with an absolute minimum estimate of 86 km or 30% and absolute maximum estimate of 275 km or 60%. We determined the maximum and minimum shortening estimates using the cross sectional area and possible variations in assumptions made about the amount of erosion, detachment dip, involvement of basement thrusts and displacement along faults. The best estimate of shortening is well short of the required 240-300km of shortening needed in order to account for a 60-70km thick crust under the entire plateau. This suggests that for an isostatically equilibrated crust either 1) there is a significant amount of shortening (~150km) in the western half of the plateau which, is hidden by the volcanic arc or 2) crustal material is being added to the Peruvian section of the Andean Plateau either through lower crustal flow or a process of magmatic underplating followed by differentiation and delamination.

  8. Source Apportionment of Elemental Carbon Across the San Francisco Bay Area Using Combined Radiocarbon and Chemical Mass Balances

    Science.gov (United States)

    Yoon, S.; Fairley, D.; Sheesley, R. J.

    2014-12-01

    The San Francisco Bay Area is impacted by ambient particulate matter (PM) from a variety of sources including motor vehicles, biomass burning, off-road vehicles, industry, and meat cooking. Ambient PM, especially fine PM (diameter less than 2.5μm, PM2.5), is known to negatively impact health. Elemental Carbon (EC) is one of the major constituents of PM2.5. It not only negatively affects health but is also a powerful short-lived climate forcer. The State of California and Bay Area Air Quality Management District (BAAQMD) have made efforts in regulating contribution of EC from diesel trucks and wood burning, respectively. These and other efforts have assisted in significantly reducing the annual average PM2.5 concentrations approximately 30% since 2005 and 70% since 1990. Despite these improvements, to better determine the relative contribution of contemporary vs. fossil carbon, radiocarbon source apportionment of EC was conducted on PM2.5 collected in the Bay Area. Measurements of the abundance of 14C in the EC fractions are used to quantify the relative contributions of fossil carbon (fossil fuel combustion, including motor vehicle exhaust) and contemporary carbon (biomass combustion and meat cooking). This comprehensive study included seven sites in the Bay Area and 12 months of sampling starting November 2011 through October 2012. The samples were composited to represent winter (November-February) and non-winter (March-October). In addition to radiocarbon analysis, Chemical Mass Balance (CMB) analysis using bulk PM2.5 composition and selected trace gases was used to understand the split among gasoline, natural gas, and diesel exhaust. Preliminary apportionment of the seven sites shows roughly equal contributions of fossil fuel and biomass burning/cooking for both winter and non-winter samples. There is evidence that the diesel contribution to EC, in particular, has decreased substantially over the last decade.

  9. Evaluation of mass balance, 4D-Var, and hybrid approaches to constraining NOx emissions using OMI NO2 remote sensing measurements.

    Science.gov (United States)

    Qu, Z.

    2015-12-01

    Nitrogen oxides (NOx) contribute to photochemical smog, tropospheric ozone and aerosol, and human health problems. Remote sensing observations provide a valuable means of constraining emissions of NOx, and thus improving our ability to use air quality models for further understanding these issues. Traditional top-down estimates have provided important constraints for NOx emission inventories in China, but are either time-consuming (e.g., 4D-Var) or only crudely represent the influence of atmospheric transport and chemistry (e.g., mass balance). Here, we combine mass balance and 4D-Var approaches, and investigate the improvements in simulated NOx column density over China. Scaling factors derived from the mass balance approach with OMI observations are first applied to NOx emissions. In this process, a smoothing kernel is used to account for emissions from adjacent grid cells, and optimized NOx emissions are derived using maximum likelihood estimation, which weigh top-down and bottom up estimates by their relative errors. This is followed by subsequent inversion using an adjoint-based 4D-Var approach with GEOS-Chem at the 0.5x0.667 degree resolution. We consider the correlations between errors in neighboring grid cells by using off-diagonal terms in scaling factors' error covariance matrix. An optimal value of the regularization parameter is selected using an L-curve and minimization of total error. We compare the solutions obtained using this hybrid approach with that obtained from standard 4D-Var, as well as to the direct solution from the mass balance approach itself. Differences between these methods in specific grid cells are investigated. We demonstrate the effect of transport and chemistry on the performance of mass balance and 4D-Var, identifying cases where the smoothing kernel and weighting errors in mass balance can cause the scaling factor to be in a direction that occasionally increases residual error. This study shows potential to facilitate decadal

  10. Alternate strategies to obtain mass balance without the use of radiolabeled compounds: application of quantitative fluorine (19F) nuclear magnetic resonance (NMR) spectroscopy in metabolism studies.

    Science.gov (United States)

    Mutlib, Abdul; Espina, Robert; Atherton, James; Wang, Jianyao; Talaat, Rasmy; Scatina, JoAnn; Chandrasekaran, Appavu

    2012-03-19

    Nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in the quantitation of small and large molecules. Recently, we demonstrated that (1)H NMR could be used to quantitate drug metabolites isolated in submilligram quantities from biological sources. It was shown that these metabolites, once quantitated by NMR, were suitable to be used as reference standards in quantitative LC/MS-based assays, hence circumventing the need for radiolabeled material or synthetic standards to obtain plasma exposure estimates in humans and preclinical species. The quantitative capabilities of high-field NMR is further demonstrated in the current study by obtaining the mass balance of fluorinated compounds using (19)F-NMR. Two fluorinated compounds which were radio-labeled with carbon-14 on metabolically stable positions were dosed in rats and urine and feces collected. The mass balance of the compounds was obtained initially by counting the radioactivity present in each sample. Subsequently, the same sets of samples were analyzed by (19)F-NMR, and the concentrations determined by this method were compared with data obtained using radioactivity counting. It was shown that the two methods produced comparable values. To demonstrate the value of this analytical technique in drug discovery, a fluorinated compound was dosed intravenously in dogs and feces and urine collected. Initial profiling of samples showed that this compound was excreted mainly unchanged in feces, and hence, an estimate of mass balance was obtained using (19)F-NMR. The data obtained by this method was confirmed by additional quantitative studies using mass spectrometry. Hence cross-validations of the quantitative (19)F-NMR method by radioactivity counting and mass spectrometric analysis were demonstrated in this study. A strategy outlining the use of fluorinated compounds in conjunction with (19)F-NMR to understand their routes of excretion or mass balance in animals is proposed. These

  11. Mass balance of the Greenland ice sheet (2003–2008 from ICESat data – the impact of interpolation, sampling and firn density

    Directory of Open Access Journals (Sweden)

    L. S. Sørensen

    2011-03-01

    Full Text Available ICESat has provided surface elevation measurements of the ice sheets since the launch in January 2003, resulting in a unique dataset for monitoring the changes of the cryosphere. Here, we present a novel method for determining the mass balance of the Greenland ice sheet, derived from ICESat altimetry data.

    Three different methods for deriving elevation changes from the ICESat altimetry dataset are used. This multi-method approach provides a method to assess the complexity of deriving elevation changes from this dataset.

    The altimetry alone can not provide an estimate of the mass balance of the Greenland ice sheet. Firn dynamics and surface densities are important factors that contribute to the mass change derived from remote-sensing altimetry. The volume change derived from ICESat data is corrected for changes in firn compaction over the observation period, vertical bedrock movement and an intercampaign elevation bias in the ICESat data. Subsequently, the corrected volume change is converted into mass change by the application of a simple surface density model, in which some of the ice dynamics are accounted for. The firn compaction and density models are driven by the HIRHAM5 regional climate model, forced by the ERA-Interim re-analysis product, at the lateral boundaries.

    We find annual mass loss estimates of the Greenland ice sheet in the range of 191 ± 23 Gt yr−1 to 240 ± 28 Gt yr−1 for the period October 2003 to March 2008. These results are in good agreement with several other studies of the Greenland ice sheet mass balance, based on different remote-sensing techniques.

  12. An MINLP Model that Includes the Effect of Temperature and Composition on Property Balances for Mass Integration Networks

    Directory of Open Access Journals (Sweden)

    Arturo Jiménez-Gutiérrez

    2014-08-01

    Full Text Available The synthesis of water networks based on properties has commonly ignored the effect of temperature on the property balances that are part of the formulation. When wide differences of temperatures are observed within the process, such an effect might yield significant errors in the application of conventional property balances. In this work, a framework for the development of water networks that include temperature effects on property balances is presented. The approach is based on the inclusion of constants in the property operators that are commonly used to carry out the property balances. An additional term to take care of composition effects is also included. The resulting approach is embedded into a formulation based on a mixed-integer nonlinear programming model for the design of water networks. A case study is presented that shows that the proposed approach yields an improvement in the prediction of the resulting properties for the integrated network, thus affecting the optimal solution.

  13. Development of heat and mass balance analysis code in out-of-pile hydrogen production system for HTTR heat utilization system (contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Yoshitomo; Inagaki, Yoshiyuki; Hayashi, Koji; Suyama, Kazumasa [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    1999-03-01

    A heat and mass balance analysis code has been developed to examine test conditions, to investigate transient behavior etc. in the out-of-pile hydrogen production system for the HTTR heat utilization system. The code can analyze temperature, mass and pressure profiles of helium and process gases and behavior of the control system under both static state (case of steady operation) and dynamic state (case of transient operation). This report describes analytical methods, basic equations and constitution of the code, and how to make of the input data, estimate of the analytical results and so on. (author)

  14. Assessment of interannual variations in the surface mass balance of 18 Svalbard glaciers from the Moderate Resolution Imaging Spectroradiometer/Terra albedo product

    OpenAIRE

    W. Greuell; Kohler, J.; F. Obleitner; Glowacki, P.; Melvold, K.; Bernsen, E.; J. Oerlemans

    2007-01-01

    We estimate annual anomalies of the surface mass balance of glaciers on Svalbard for the period 2000–2005 (six years), by calculating the so-called ‘‘satellite-derived mass balance’’ (Bsat) from time series of satellite-derived surface albedos. The method needs no other input variables. Surface albedos are extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra albedo product. We validate the MODIS albedos by comparing them with in situ measurements on Kongsvegen, and w...

  15. Assessing modeled Greenland surface mass balance in the GISS Model E2 and its sensitivity to surface albedo

    Science.gov (United States)

    Alexander, Patrick; LeGrande, Allegra N.; Koenig, Lora S.; Tedesco, Marco; Moustafa, Samiah E.; Ivanoff, Alvaro; Fischer, Robert P.; Fettweis, Xavier

    2016-04-01

    The surface mass balance (SMB) of the Greenland Ice Sheet (GrIS) plays an important role in global sea level change. Regional Climate Models (RCMs) such as the Modèle Atmosphérique Régionale (MAR) have been employed at high spatial resolution with relatively complex physics to simulate ice sheet SMB. Global climate models (GCMs) incorporate less sophisticated physical schemes and provide outputs at a lower spatial resolution, but have the advantage of modeling the interaction between different components of the earth's oceans, climate, and land surface at a global scale. Improving the ability of GCMs to represent ice sheet SMB is important for making predictions of future changes in global sea level. With the ultimate goal of improving SMB simulated by the Goddard Institute for Space Studies (GISS) Model E2 GCM, we compare simulated GrIS SMB against the outputs of the MAR model and radar-derived estimates of snow accumulation. In order to reproduce present-day climate variability in the Model E2 simulation, winds are constrained to match the reanalysis datasets used to force MAR at the lateral boundaries. We conduct a preliminary assessment of the sensitivity of the simulated Model E2 SMB to surface albedo, a parameter that is known to strongly influence SMB. Model E2 albedo is set to a fixed value of 0.8 over the entire ice sheet in the initial configuration of the model (control case). We adjust this fixed value in an ensemble of simulations over a range of 0.4 to 0.8 (roughly the range of observed summer GrIS albedo values) to examine the sensitivity of ice-sheet-wide SMB to albedo. We prescribe albedo from the Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A3 v6 to examine the impact of a more realistic spatial and temporal variations in albedo. An age-dependent snow albedo parameterization is applied, and its impact on SMB relative to observations and the RCM is assessed.

  16. A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye

    KAUST Repository

    Gaffney, E.A.

    2010-01-01

    Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model for the mass and solute balance of the tears, with parameter estimation based on extensive data from the literature which permits the influence of tear evaporation, lacrimal flux and blink rate on tear osmolarity to be explored. In particular the nature of compensatory events has been estimated in aqueous-deficient (ADDE) and evaporative (EDE) dry eye. The model reproduces observed osmolarities of the tear meniscus for the healthy eye and predicts a higher concentration in the tear film than meniscus in normal and dry eye states. The differential is small in the normal eye, but is significantly increased in dry eye, especially for the simultaneous presence of high meniscus concentration and low meniscus radius. This may influence the interpretation of osmolarity values obtained from meniscus samples since they need not fully reflect potential damage to the ocular surface caused by tear film hyperosmolarity. Interrogation of the model suggests that increases in blink rate may play a limited role in compensating for a rise in tear osmolarity in ADDE but that an increase in lacrimal flux, together with an increase in blink rate, may delay the development of hyperosmolarity in EDE. Nonetheless, it is predicted that tear osmolarity may rise to much higher levels in EDE than ADDE before the onset of tear film breakup, in the absence of events at the ocular surface which would independently compromise tear film stability. Differences in the predicted responses of the pre-ocular tears in ADDE compared to EDE or hybrid disease to defined conditions suggest that no single, empirically-accessible variable can act as a surrogate for tear film concentration and the potential for ocular surface damage. This emphasises the need to measure

  17. A downscaled 1 km dataset of daily Greenland ice sheet surface mass balance components (1958-2014)

    Science.gov (United States)

    Noel, B.; Van De Berg, W. J.; Fettweis, X.; Machguth, H.; Howat, I. M.; van den Broeke, M. R.

    2015-12-01

    The current spatial resolution in regional climate models (RCMs), typically around 5 to 20 km, remains too coarse to accurately reproduce the spatial variability in surface mass balance (SMB) components over the narrow ablation zones, marginal outlet glaciers and neighbouring ice caps of the Greenland ice sheet (GrIS). In these topographically rough terrains, the SMB components are highly dependent on local variations in topography. However, the relatively low-resolution elevation and ice mask prescribed in RCMs contribute to significantly underestimate melt and runoff in these regions due to unresolved valley glaciers and fjords. Therefore, near-km resolution topography is essential to better capture SMB variability in these spatially restricted regions. We present a 1 km resolution dataset of daily GrIS SMB covering the period 1958-2014, which is statistically downscaled from data of the polar regional climate model RACMO2.3 at 11 km, using an elevation dependence. The dataset includes all individual SMB components projected on the elevation and ice mask from the GIMP DEM, down-sampled to 1 km. Daily runoff and sublimation are interpolated to the 1 km topography using a local regression to elevation valid for each day specifically; daily precipitation is bi-linearly downscaled without elevation corrections. The daily SMB dataset is then reconstructed by summing downscaled precipitation, sublimation and runoff. High-resolution elevation and ice mask allow for properly resolving the narrow ablation zones and valley glaciers at the GrIS margins, leading to significant increase in runoff estimate. In these regions, and especially over narrow glaciers tongues, the downscaled products improve on the original RACMO2.3 outputs by better representing local SMB patterns through a gradual ablation increase towards the GrIS margins. We discuss the impact of downscaling on the SMB components in a case study for a spatially restricted region, where large elevation

  18. Ideal climatic variables for the present-day geometry of the Gregoriev Glacier, Inner Tien Shan, Kyrgyzstan, derived from GPS data and energy-mass balance measurements

    Directory of Open Access Journals (Sweden)

    K. Fujita

    2011-03-01

    Full Text Available We conducted 2 yr (2005–2007 of in situ meteorological and glaciological observations on the Gregoriev Glacier, a flat-top glacier within the Inner Tien Shan, Kyrgyzstan. Differential GPS surveys reveal a vertical surface deletion at the summit of the glacier. Based on snow density data and an energy-mass balance model, we estimate that the annual precipitation and summer mean temperature required to maintain the glacier in the modern state are 289 mm and −3.85 °C at the glacier summit (4600 m above sea level, a.s.l., respectively. The good agreement between the long-term estimated and observed precipitation at a nearby station in the Tien Shan (292 mm at 3614 m a.s.l. for the period 1930–2002 suggests that the glacier dynamics have been regulated by the long-term average accumulation. The glacier mass-balance, reconstructed based on meteorological data from the Tien Shan station for the past 80 yr, explains the observed fluctuations in glacier extent, particularly the negative mass balance in the 1990s.

  19. Perioperative growth hormone treatment increases nitrogen and fluid balance and results in short-term and long-term conservation of lean tissue mass

    DEFF Research Database (Denmark)

    Jensen, Martin Bach; Kissmeyer-Nielsen, Peter; Laurberg, Søren

    1998-01-01

    , 3.6 kg (2.1, 5.1) lean tissue mass, and 0.5 kg (-0.1, 1.2) fat mass. These reductions persisted 3 mo later. Compared with placebo, GH improved nitrogen balance, changes in lean tissue mass [gain of 4.0 kg (1.9, 6.0), P=0.001], and changes in total tissue mass [gain of 3.2 kg (1.6, 4.9), P=0.......001], but increased the loss of fat mass [loss of 0.7 kg (0.0, 1.5), P=0.049] on postoperative day 7. Three months later, the placebo-treated patients had lost 2.4 kg (0.7, 4.2) more lean tissue mass than GH-treated patients (P=0.009), whereas changes in total tissue and fat mass were not significantly different....... Hence, GH treatment enhanced the long-term regain of lean tissue mass....

  20. 南极冰盖物质平衡最新研究进展%An up to date review on the mass balance over Antarctica

    Institute of Scientific and Technical Information of China (English)

    丁明虎

    2013-01-01

    The assessment of mass balance in Antarctica is one of the basic issues for global sea level change under climate change. During the past decades, scientists have conducted many in-situ measurements in the major glacier basins of Antarctica, under the guidance of ITASE (International Trans Antarctic Scientific Expedition) and ISMASS (Ice Sheet Mass Balance and Sea Level) projects. Furthermore, the data collected by satellite altimeter and gravity sensor, hastened the study on mass balance over Antarctica significantly. However, both of the methods have its own limitations, such as the post-rebound effect for GRACE satellite. The combination of in-situ measurement and satellite will be the emphasis in future studies. This paper will focus on the mass balance and provide the up to date researches.%探明南极冰盖物质平衡状况,对研究全球变暖背景下海平面变化具有重要意义,也是南极冰川学的重要基础工作.在ITASE计划(International Trans Antarctic Scientific Expedition)和ISMASS计划(Ice Sheet Mass Balance and Sea Level)的指导下,各国科学家对南极几个主要流域进行了大范围的实地观测,获取了一些重要成果.此外,由于极地测高卫星和重力卫星的应用,南极冰盖整体物质平衡状况评估在近期得到长足发展.无论是实地研究还是卫星遥感,都有其局限性,两者结合可以弥补各自的缺陷,是未来研究的主要发展方向,但目前仍未引起足够的重视.因此,本文综述了南极冰盖物质平衡研究的最新研究进展,将有关研究分局域和洲际尺度进行了介绍,并对国内的研究提出建议.

  1. 广义质量替代的曲柄群机构动平衡%Dynamic balancing of crank group mechanism based on generalized mass substitution

    Institute of Scientific and Technical Information of China (English)

    刘言松; 曹巨江

    2016-01-01

    根据曲柄群机构中连杆桁架的质心分布特点,利用广义质量替代法将连杆桁架质量向曲柄与连杆桁架的3个铰接点替代,从而将曲柄群机构分解为若干个I类和II类曲柄单元,把曲柄群机构的动平衡问题转化为I类曲柄单元的动平衡问题。计算表明。当 I 类曲柄单元实现动平衡时,曲柄群机构也实现了动平衡。结论对简化曲柄群机构的结构,减少该机构的基础振动具有较好的指导意义。%According to the distribution characteristics of center of mass of the crank group mechanism,the mechanism is broken into some crank units named class I crank unit or class II crank unit,by generalized mass substitution in which the mass of the connecting rod truss is substituted on the 3 hinged points,and the dynamic balancing of the crank group mecha-nism is converted to the dynamic balance of class I crank unit.The calculation example shows that the crank group mechanism is a dynamic balancing mechanism when each class I crank unit is a dynamic balancing rotor.The conclusions may be helpful for reducing the foundation vibration of the mechanism and simplifying the structure in the design of the crank group mechanism.

  2. Modelagua, a new interactive program of inverse mass-balance model for hydrogeochemical studies -- an example of its application in Aguascalientes, Mexico

    Science.gov (United States)

    Gonzalez, P.; Fagundo, J.; Fagundo, R.; Suárez, M.; Melian, C.; Cortes, A.; Ramos, J. A.

    2003-04-01

    The geochemical models consists on the application of physical-chemical principles to the interpretation of hydrogeochemical systems. This methodology has been developed according to two approaches: a) the inverse one, mass-balance, that uses a well-known data of the chemical composition of the water and the rock with the objective of identifying in a quantitative way the geochemical reactions that give origin to this composition, and b) the direct one that in the basis of some well-known initial conditions of the water-rock system, it predicts the characteristics of the resulting solution of the performance of hypothetical chemical reactions. With the reference of interactive programs such as BALANCE and NETPATH, for modelling net geochemical mass-balance reactions between an initial and final water along a hydrologic flow path, which also computes the mixing proportion of two initial waters and net geochemical reactions that can account for the observed composition of a final water, an interactive program of inverse model has been developed (MODELAGUA) that not only allow starting from well-known data of the chemical composition of the water and the rock to identify in a quantitative way the geochemical reactions that give origin to this composition, but allow to do analysis of mixture of waters and net geochemical reactions that can account for the observed composition of a final water, making use of natural tracer whose geochemical behavior allows them to be used as conservative ions. In this work is presented MODELAGUA, as a new interactive program of inverse model mass-balance and an example in Aguascalientes, Mexico of its application.

  3. Investigation of chamber methods and a micrometeorological mass balance method for quantifying greenhouse gas emissions from animal manure

    Science.gov (United States)

    Park, Kyu-Hyun

    Various measurement methods to quantify greenhouse gas (GHG) emissions from manure storage or treatment facilities have been used. However, it is difficult to directly compare emission data measured with different methods, which causes uncertainties in national GHG inventories. In the micrometeorological mass balance (MMB) method, a gas flux consists of a horizontal mean flux (MF) and horizontal turbulent flux (TF) terms. In Chapter 2, methane (GH4 ) TF measurements obtained using a sonic anemometer and a tunable diode laser trace gas analyzer are presented. Contrary to previous studies in wind tunnels and flat-level field conditions, an overestimation of only 0.5% was observed by only considering the MF term. This means the MMB method without consideration of TF is suitable in complex field conditions with uneven topography, and farm buildings. In Chapter 3, the MMB method was compared to a floating chamber method. Of these, the floating chamber method has been extensively used for CH4 flux quantification. The MMB method, although providing advantages such as spatial integration of fluxes, requires fast response trace gas analyzers which are not widely available. The mean ratio of CH4 flux measured with the floating chamber method to that measured using the MMB method was 1.25, ranging from 1.07 to 1.83. Flux overestimation by the floating chamber could have been caused by location of the chamber and potential disturbances by the chamber. Frequent changes of the chamber location, use of several chambers, and/or avoiding chamber placement on 'hot spots' are recommended to decrease flux overestimation. In Chapter 4, CH4 fluxes measured with a mega chamber and eight small chambers during the in-vessel composting phase showed similar temporal variation, while nitrous oxide (N2O) fluxes were, significantly lower for the small chambers. The ratios of CH4 fluxes measured with a mega chamber to eight small chambers during the in-vessel composting phase were 0.72 and 1

  4. Barrow real-time sea ice mass balance data: ingestion, processing, dissemination and archival of multi-sensor data

    Science.gov (United States)

    Grimes, J.; Mahoney, A. R.; Heinrichs, T. A.; Eicken, H.

    2012-12-01

    Sensor data can be highly variable in nature and also varied depending on the physical quantity being observed, sensor hardware and sampling parameters. The sea ice mass balance site (MBS) operated in Barrow by the University of Alaska Fairbanks (http://seaice.alaska.edu/gi/observatories/barrow_sealevel) is a multisensor platform consisting of a thermistor string, air and water temperature sensors, acoustic altimeters above and below the ice and a humidity sensor. Each sensor has a unique specification and configuration. The data from multiple sensors are combined to generate sea ice data products. For example, ice thickness is calculated from the positions of the upper and lower ice surfaces, which are determined using data from downward-looking and upward-looking acoustic altimeters above and below the ice, respectively. As a data clearinghouse, the Geographic Information Network of Alaska (GINA) processes real time data from many sources, including the Barrow MBS. Doing so requires a system that is easy to use, yet also offers the flexibility to handle data from multisensor observing platforms. In the case of the Barrow MBS, the metadata system needs to accommodate the addition of new and retirement of old sensors from year to year as well as instrument configuration changes caused by, for example, spring melt or inquisitive polar bears. We also require ease of use for both administrators and end users. Here we present the data and processing steps of using sensor data system powered by the NoSQL storage engine, MongoDB. The system has been developed to ingest, process, disseminate and archive data from the Barrow MBS. Storing sensor data in a generalized format, from many different sources, is a challenging task, especially for traditional SQL databases with a set schema. MongoDB is a NoSQL (not only SQL) database that does not require a fixed schema. There are several advantages using this model over the traditional relational database management system (RDBMS

  5. Multicompartment ecosystem mass balances as a tool for understanding and managing the biogeochemical cycles of human ecosystems.

    Science.gov (United States)

    Baker, L A; Hope, D; Xu, Y; Edmonds, J

    2001-10-09

    Nitrogen remains a ubiquitous pollutant in surface and groundwater throughout the United States, despite 30 years of pollution control efforts. A detailed multicompartment N balance for the Central Arizona-Phoenix ecosystem is used to illustrate how an ecosystem-level approach can be used to develop improved N management strategies. The N balance is used to demonstrate how nitrate in pumped groundwater used for crop irrigation could be used to reduce inputs of commercial fertilizer and decrease N leaching to aquifers. Effectively managing N pollution also will require an understanding of the complex factors that control the N balance, including targeted regulations, individual human behavior, land-use conversion, and other ecosystem management practices that affect the N balance. These sometimes countervailing factors are illustrated with several scenarios of wastewater treatment technology and population growth in the Phoenix area. Management of N eventually must be coupled to management of other elements, notably carbon, phosphorus, and salts. We postulate that an ecosystem framework for pollution management will result in strategies that are more effective, fairer, and less expensive than current approaches.

  6. On the impact of using downscaled reanalysis data instead of direct measurements for modeling the mass balance of a tropical glacier (Cordillera Blanca, Peru)

    Science.gov (United States)

    Galos, Stephan; Hofer, Marlis; Marzeion, Ben; Mölg, Thomas; Großhauser, Martin

    2013-04-01

    Due to their setting, tropical glaciers are sensitive indicators of mid-tropospheric meteorological variability and climate change. Furthermore these glaciers are of particular interest because they respond faster to climatic changes than glaciers located in mid- or high-latitudes. As long-term direct meteorological measurements in such remote environments are scarce, reanalysis data (e.g. ERA-Interim) provide a highly valuable source of information. Reanalysis datasets (i) enable a temporal extension of data records gained by direct measurements and (ii) provide information from regions where direct measurements are not available. In order to properly derive the physical exchange processes between glaciers and atmosphere from reanalysis data, downscaling procedures are required. In the present study we investigate if downscaled atmospheric variables (air temperature and relative humidity) from a reanalysis dataset can be used as input for a physically based, high resolution energy and mass balance model. We apply a well validated empirical-statistical downscaling model, fed with ERA-Interim data, to an automated weather station (AWS) on the surface of Glaciar Artesonraju (8.96° S | 77.63° W). The downscaled data is then used to replace measured air temperature and relative humidity in the input for the energy and mass balance model, which was calibrated using ablation data from stakes and a sonic ranger. In order to test the sensitivity of the modeled mass balance to the downscaled data, the results are compared to a reference model run driven solely with AWS data as model input. We finally discuss the results and present future perspectives for further developing this method.

  7. Linking morphodynamic response with sediment mass balance on the Colorado River in Marble Canyon: issues of scale, geomorphic setting, and sampling design

    Science.gov (United States)

    Grams, Paul E.; Topping, David J.; Schmidt, John C.; Hazel, Joseph E., Jr.; Kaplinski, Matt

    2013-01-01

    Measurements of morphologic change are often used to infer sediment mass balance. Such measurements may, however, result in gross errors when morphologic changes over short reaches are extrapolated to predict changes in sediment mass balance for long river segments. This issue is investigated by examination of morphologic change and sediment influx and efflux for a 100 km segment of the Colorado River in Grand Canyon, Arizona. For each of four monitoring intervals within a 7 year study period, the direction of sand-storage response within short morphologic monitoring reaches was consistent with the flux-based sand mass balance. Both budgeting methods indicate that sand storage was stable or increased during the 7 year period. Extrapolation of the morphologic measurements outside the monitoring reaches does not, however, provide a reasonable estimate of the magnitude of sand-storage change for the 100 km study area. Extrapolation results in large errors, because there is large local variation in site behavior driven by interactions between the flow and local bed topography. During the same flow regime and reach-average sediment supply, some locations accumulate sand while others evacuate sand. The interaction of local hydraulics with local channel geometry exerts more control on local morphodynamic response than sand supply over an encompassing river segment. Changes in the upstream supply of sand modify bed responses but typically do not completely offset the effect of local hydraulics. Thus, accurate sediment budgets for long river segments inferred from reach-scale morphologic measurements must incorporate the effect of local hydraulics in a sampling design or avoid extrapolation altogether.

  8. Decadal region-wide and glacier-wide mass balances derived from multi-temporal ASTER satellite digital elevation models. Validation over the Mont-Blanc area

    Science.gov (United States)

    Berthier, Etienne; Cabot, Vincent; Vincent, Christian; Six, Delphine

    2016-06-01

    Since 2000, a vast archive of stereo-images has been built by the Advanced Spaceborne Thermal Emission and Reflection (ASTER) satellite. Several studies already extracted glacier mass balances from multi-temporal ASTER digital elevation models (DEMs) but they lacked accurate independent data for validation. Here, we apply a linear regression to a time series of 3D-coregistered ASTER DEMs to estimate the rate of surface elevation changes (dh/dtASTER) and geodetic mass balances of Mont-Blanc glaciers (155 km²) between 2000 and 2014. Validation using field and spaceborne geodetic measurements reveals large errors at the individual pixel level (> 1 m a-1) and an accuracy of 0.2-0.3 m a-1 for dh/dtASTER averaged over areas larger than 1 km². For all Mont-Blanc glaciers, the ASTER region-wide mass balance (-1.05±0.37 m water equivalent (w.e.) a-1) agrees remarkably with the one measured using Spot5 and Pléiades DEMs (-1.06±0.23 m w.e. a-1) over their common 2003-2012 period. This multi-temporal ASTER DEM strategy leads to smaller errors than the simple differencing of two ASTER DEMs. By extrapolating dh/dtASTER to mid-February 2000, we infer a mean penetration depth of about 9±3 m for the C-band Shuttle Radar Topographic Mission (SRTM) radar signal, with a strong altitudinal dependency (range 0-12 m). This methodology thus reveals the regional pattern of glacier surface elevation changes and improves our knowledge of the penetration of the radar signal into snow and ice.

  9. Geodetic mass balance record with rigorous uncertainty estimates deduced from aerial photographs and lidar data - Case study from Drangajökull ice cap, NW Iceland

    Science.gov (United States)

    Magnússon, E.; Muñoz-Cobo Belart, J.; Pálsson, F.; Ágústsson, H.; Crochet, P.

    2016-01-01

    In this paper we describe how recent high-resolution digital elevation models (DEMs) can be used to extract glacier surface DEMs from old aerial photographs and to evaluate the uncertainty of the mass balance record derived from the DEMs. We present a case study for Drangajökull ice cap, NW Iceland. This ice cap covered an area of 144 km2 when it was surveyed with airborne lidar in 2011. Aerial photographs spanning all or most of the ice cap are available from survey flights in 1946, 1960, 1975, 1985, 1994 and 2005. All ground control points used to constrain the orientation of the aerial photographs were obtained from the high-resolution lidar DEM. The lidar DEM was also used to estimate errors of the extracted photogrammetric DEMs in ice- and snow-free areas, at nunataks and outside the glacier margin. The derived errors of each DEM were used to constrain a spherical semivariogram model, which along with the derived errors in ice- and snow-free areas were used as inputs into 1000 sequential Gaussian simulations (SGSims). The simulations were used to estimate the possible bias in the entire glaciated part of the DEM and the 95 % confidence level of this bias. This results in bias correction varying in magnitude between 0.03 m (in 1975) and 1.66 m (in 1946) and uncertainty values between ±0.21 m (in 2005) and ±1.58 m (in 1946). Error estimation methods based on more simple proxies would typically yield 2-4 times larger error estimates. The aerial photographs used were acquired between late June and early October. An additional seasonal bias correction was therefore estimated using a degree-day model to obtain the volume change between the start of 2 glaciological years (1 October). This correction was largest for the 1960 DEM, corresponding to an average elevation change of -3.5 m or approx. three-quarters of the volume change between the 1960 and the 1975 DEMs. The total uncertainty of the derived mass balance record is dominated by uncertainty in the volume

  10. Generalized mass action systems: Complex balancing equilibria and sign vectors of the stoichiometric and kinetic-order subspaces

    OpenAIRE

    Müller, Stefan; Regensburger, Georg

    2012-01-01

    Mass action systems capture chemical reaction networks in homogeneous and dilute solutions. We suggest a notion of generalized mass action systems that admits arbitrary nonnegative power-law rate functions and serves as a more realistic model for reaction networks in intracellular environments. In addition to the chemical complexes and the related stoichiometric subspace, we introduce corresponding kinetic complexes, which represent the nonnegative exponents in the rate functions and determin...

  11. Using The Balance Function To Search For Late Hadronization In Gold+gold Collisions At A Center Of Mass Energy Of 130 Gev Per Nucleon Pair

    CERN Document Server

    Tonjes, M B

    2002-01-01

    Relativistic heavy ion physics is the study of nuclear matter interacting at high energies and densities. The collisions of gold nuclei at the Relativistic Heavy Ion Collider (RHIC) provide a source of high density matter for the study and creation of a novel state of matter, the Quark-Gluon Plasma (QGP). The data set studied in this dissertation is taken from Au+Au interactions at a center of mass energy of 130 GeV, measured in summer 2000. This is the first such data produced at RHIC. The analysis presented here focuses upon the measurement of balance functions, which are new observables in the field of heavy ion physics. The balance function for heavy ion physics is introduced in Bass, Danielewicz, and Pratt, Phys. Rev. Lett. 85, 2689 (2000). The data were taken with the STAR (Solenoidal Tracker At RHIC) detector, with analysis performed on charged particles in a pseudorapidity region of |η| < 1.3. The balance function measured for conserving charge/anti- charge pion pairs as a function of r...

  12. Multivariate Analysis, Mass Balance Techniques, and Statistical Tests as Tools in Igneous Petrology: Application to the Sierra de las Cruces Volcanic Range (Mexican Volcanic Belt)

    Science.gov (United States)

    Velasco-Tapia, Fernando

    2014-01-01

    Magmatic processes have usually been identified and evaluated using qualitative or semiquantitative geochemical or isotopic tools based on a restricted number of variables. However, a more complete and quantitative view could be reached applying multivariate analysis, mass balance techniques, and statistical tests. As an example, in this work a statistical and quantitative scheme is applied to analyze the geochemical features for the Sierra de las Cruces (SC) volcanic range (Mexican Volcanic Belt). In this locality, the volcanic activity (3.7 to 0.5 Ma) was dominantly dacitic, but the presence of spheroidal andesitic enclaves and/or diverse disequilibrium features in majority of lavas confirms the operation of magma mixing/mingling. New discriminant-function-based multidimensional diagrams were used to discriminate tectonic setting. Statistical tests of discordancy and significance were applied to evaluate the influence of the subducting Cocos plate, which seems to be rather negligible for the SC magmas in relation to several major and trace elements. A cluster analysis following Ward's linkage rule was carried out to classify the SC volcanic rocks geochemical groups. Finally, two mass-balance schemes were applied for the quantitative evaluation of the proportion of the end-member components (dacitic and andesitic magmas) in the comingled lavas (binary mixtures). PMID:24737994

  13. Multivariate analysis, mass balance techniques, and statistical tests as tools in igneous petrology: application to the Sierra de las Cruces volcanic range (Mexican Volcanic Belt).

    Science.gov (United States)

    Velasco-Tapia, Fernando

    2014-01-01

    Magmatic processes have usually been identified and evaluated using qualitative or semiquantitative geochemical or isotopic tools based on a restricted number of variables. However, a more complete and quantitative view could be reached applying multivariate analysis, mass balance techniques, and statistical tests. As an example, in this work a statistical and quantitative scheme is applied to analyze the geochemical features for the Sierra de las Cruces (SC) volcanic range (Mexican Volcanic Belt). In this locality, the volcanic activity (3.7 to 0.5 Ma) was dominantly dacitic, but the presence of spheroidal andesitic enclaves and/or diverse disequilibrium features in majority of lavas confirms the operation of magma mixing/mingling. New discriminant-function-based multidimensional diagrams were used to discriminate tectonic setting. Statistical tests of discordancy and significance were applied to evaluate the influence of the subducting Cocos plate, which seems to be rather negligible for the SC magmas in relation to several major and trace elements. A cluster analysis following Ward's linkage rule was carried out to classify the SC volcanic rocks geochemical groups. Finally, two mass-balance schemes were applied for the quantitative evaluation of the proportion of the end-member components (dacitic and andesitic magmas) in the comingled lavas (binary mixtures). PMID:24737994

  14. Estimating the unknown components of nutrient mass balances for forestry plantations in mine rehabilitation, Upper Hunter Valley, New South Wales, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Mercuri, A.M.; Duggin, J.A.; Daniel, H.; Lockwood, P.V.; Grant, C.D. [University of New England, Armidale, NSW (Australia)

    2006-04-15

    Commercial forestry plantations as a postmining land use in the Upper Hunter Valley of New South Wales, Australia are restricted by both the poor nutrient availability of mining substrates and low regional rainfall. An experiment was conducted to investigate whether municipal waste products and saline groundwater from coal mining operations could improve early tree growth without impacting on the environment through salt accumulation and/or nutrient enrichment and changes in groundwater quality. Potential impacts were investigated by quantifying the nutrient cycling dynamics within the plantation using an input - output mass balance approach for exchangeable calcium, exchangeable magnesium, exchangeable potassium, exchangeable sodium, nitrogen, and phosphorus. Measured inputs to and outputs from the available nutrient pool in the 0 - 30 cm of the overburden subsystem were used to estimate the net effect of unmeasured inputs and outputs (termed 'residuals'). Residual values in the mass balance of the irrigated treatments demonstrated large leaching losses of exchangeable Ca, Mg, K, and Na. Between 96% and 103% of Na applied in saline mine-water irrigation was leached below the 0-30-cm soil profile zone. The fate of these salts beyond 30 cm is unknown, but results suggest that irrigation with saline mine water had minimal impact on the substrate to 30 cm over the first 2 years since plantation establishment. Accumulations of N and P were detected for the substrate amendments, suggesting that organic amendments (particularly compost) retained the applied nutrients with very little associated losses, particularly through leaching.

  15. Surface terrain characteristics and monsoon season mass balance of debris-covered glaciers in the Khumbu Himal, Nepal, obtained from high resolution Pléiades imagery.

    Science.gov (United States)

    Klug, Christoph; Nicholson, Lindsey; Rieg, Lorenzo; Sailer, Rudolf; Wirbel, Anna

    2016-04-01

    Debris-covered glaciers in the eastern Himalaya have pronounced surface relief consisting of hummocks and hollows, ice cliffs, lakes and former lake beds. This relief and spatially variable surface properties are expected to influence the spatially distributed surface energy balance and related ice mass loss and atmospheric interactions, but only a few studies have so far explicitly examined the nature of the surface terrain and its textures . In this work we present a new high-resolution digital terrain model (DTM) of a portion of the Khumbu Himal in the eastern Nepalese Himalaya, derived from Pléiades satellite imagery sampled in spring 2015. We use this DTM to study the terrain characteristics of five sample glaciers and analyse the inter- and intra- glacier variability of terrain characteristics in the context of glacier flow velocities and surface changes presented in previous studies in the area. In parallel to this analysis we also present the seasonal geodetic mass balance between spring and fall 2015, and relate it to the terrain properties, surface velocity and limited knowledge of the local lapse rates in meteorological conditions during this monsoon season.

  16. Transfer and Mass Balance of Ellagitannins, Anthocyanins, Flavan-3-ols, and Flavonols during the Processing of Red Raspberries (Rubus idaeus L.) to Juice.

    Science.gov (United States)

    Sójka, Michał; Macierzyński, Jakub; Zaweracz, Wojciech; Buczek, Maria

    2016-07-13

    The putative health benefits of raspberries and raspberry-based products are potentially attributable to the presence of polyphenolic compounds, such as ellagitannins, anthocyanins, flavanols, and flavonols. Their content in the products of raspberry processing into juice may be affected by the fruit cultivar, technological process parameters, and the properties of the polyphenolics themselves. The objective of the study was to investigate the composition and quantity of the above polyphenolics in raspberries and the products of their processing (that is, juice and press cake